Summaries of FY 1978 Research in Nuclear Physics, Summaries of Nuclear Physics

Download Summaries of FY 1978 Research in Nuclear Physics and more Summaries Nuclear Physics in PDF only on Docsity! DOE/ER-0020 U C -2 & 34c SUM M ARIES OF FY 1978 RESEARCH IN NUCLEAR PHYSICS - NOTICE- Thfr i t f o i t wai »* o f woik ipow o rtd by i'nU«d S u w i CovemfiHrtL Nehtur the United l u w i i>oi th« O'nJrtd S l» i« D fpu fm en i u\ Fjw igy, Mr in y o f ih*H em-.loyeei, not i f ty o f (heir f t ib c o n ifid o r i, o f lh*i» em ptoyK*, irufcei any *» ir»n ty , ix p i t u or PmpUfii <* ittu m e i w y k j i l liab ility o» iHporwbllMy for the i to j r ic y , compkieneH <a u teA ilnm o f »ny in forrm U W , ip p |r , ,u * ' P ^ y t i or process d *c ld # d , or repr«KA& iha« H i u # wouW n<r. ( f t f ito te p r iv ite ly o w ttd r ith t t _ _ _ _ _ _ _ _ December 1978 U.S. Department of Energy Office of Energy Research Division of Nuciear Physics Washington, DC 20645 TABLE OP CONTENTS A . I N T R O D U C T I O N 1 B . MEDIUM ENE RGY N U C L E A R P H Y S I C S - RE SE A RCH 2 A r g o n n e N a t i o n a l L a b o r a t o r y 1 1 « . 3 B r o o k h a v e n N a t i o n a l L a b o r a t o r y 5 C a l i f o r n i a , U n i v e r s i t y o f / L o s A n g e l e s 7 C a l i f o r n i a I n s t i t u t e o f T e c h n o l o g y 9 C a r n e g i e - i l e l l o n U n i v e r s i t y , .................................. ...... 10 Case W e s t e r n R e s e r v e U n i v e r s i t y t . 12 C h i c a g o , U n i v e r s i t y o f f , , , ...................................................................... 13 C o l o r a d o , U n i v e r s i t y o f , , , ...................................................................... 14 H o u s t o n , U n i v e r s i t y o f , , ............................................................................. 15 I d a h o N u c l e a r E n g i n e e r i n g L a b o r a t o r y ......................................... , 16 J o h n s H o p k i n s U n i v e r s i t y o f ................................................................................. 1 7 L a w r e nc e B e r k e l e y L a b o r a t o r y ............................................................................ 18 L a w r enc e L i v e r m o r e L a b o r a t o r y ........................................................................... 21 Los Alamos S c i e n t i f i c L a b o r a t o r y .................................. . . . . 22 M a s s a c h u s e t t s , U n i v e r s i t y g f ...................................................... ...... , , , 29 M a s s a c h u s e t t s I n s t i t u t e o f T e c h n o l o g y ................................................ 30 M i n n e s o t a , U n i v e r s i t y o f , ............................................................. 36 M o n t a n a , U n i v e r s i t y o f , . ... ............................................................................ 37 Mew M e x i c o , U n i v e r s i t y o f <. . ............................................................................. 38 New M e x i c o S t a t e U n i v e r s i t y , , ............................................................... ...... 39 N o r t h w e s t e r n U n i v e r s i t y .............................................................................................. Oak R i d g e N a t i o n a l L a b o r a t o r y y P e n n s y l v a n i a , U n i v e r s i t y o f ................................................................................. P r l n c e t u n U n i v e r s i t y , , , , ............................................................................ P u rd u e U n i v e r s i t y .................................. ...... .......................................................................... R i c e U n i v e r s i t y ................................................................................. ........................................ J® R o c h e s t e r , U n i v e r s i t y o f , , ............................................................................. Tem pl e U n i v e r s i t y .................................. ................................................................................ ^ T ex a s A&M U n i v e r s i t y ..............................................................................................., T e x a s , U n i v e r s i t y o f .......................................................................................... j?’ V a s s a r C o l l e g e .................................................................... ^ V i r g i n i a , U n i v e r s i t y o f ......................................... . ......................................... ^ W a s h i n g t o n , U n i v e r s i t y o f ............................................................. ...... . . . ^ Wy omi ng, U n i v e r s i t y o f ............................................................................................... Y a l e U n i v e r s i t y ........................... , 0 . MEDIUM E N E RG Y N U C L E A R P H Y S I C S - O P E R A T I O N S 59 P age L o s Alamos S c i e n t i f i c L a b o r a t o r y 60 M a s s a c h u s e t t s I n s t i t u t e o f T e c h n o l o g y , , , ........................... ^3 T h i s r e p o r t c o n t a i n s summaries o f p ro g r a ms f un de d i n F i s c a l Y e a r 1 9 7 8 by t h e D i v i s i o n o f N u c l e a r P h y s i c s , O f f i c e o f H i g h E n e r g y and N u c l e a r P h y s i c s , U . S . D e p a r t m e n t o f E n e r g y . A l l d o l l a r f i g u r e s r e f e r t o o p e r a t i n g f u n d s o n l y and do n o t i n c l u d e c a p i t a l e q ui p me n t ( e q u i p m e n t whose t i t l e v e s t s i n t he U n i t e d S t a t e s G o v e r nm e nt ) o r c o n s t r u c t i o n f u n d s . The l o n g r a n g e g o a l and o b j e c t i v e s o f N u c l e a r P h y s i c s a r e as f o l l o w s : , L o n g r an g e g o a l : T o a t t a i n d e e p e r u n d e r s t a n d i n g o f t h e s t r u c t u r e and p r o p e r t i e s o f a t o m i c n u c l e i and t h e laws g o v e r n i n g t h e i r m o t i o n s and i n t e r a c t i o n s t h r o u g h e x p e r i m e n t a l medium e n e r g y and h e a v y i o n n u c l e a r r e s e a r c h and t h e o r e t i c a l s t u d i e s . N u c l e a r P h y s i c s - s u p p o r t e d b a s i c r e s e a r c h p r o v i d e s u n d e r l y i n g s c i e n t i f i c k nowl edge w h i c h i s e s s e n t i a l f o r t h e d e v e l o p m e n t o f advanced n u c l e a r e n e r g y t e c h n o l o g i e s . M a j o r o b j e c t i v e s : 1 . To p u r su e f r o n t i e r n u c l e a r r e s e a r c h s t u d i e s o f t h e i n t e r ­ a c t i o n s o f n u c l e i w i t h p ro b e s o f h e a v y i o n s and o f medium e n e r g y p r i m a r y and s e c o n d a r y p a r t i c l e s ; 2 . To o p e r a t e t h e n a t i o n a l a c c e l e r a t o r f a c i l i t i e s ( C l i n t o n P . A n d e r s o n Meson P h y s i c s F a c i l i t y ( L A M P F ) , W i l l i a m H . B a t e s E l e c t r o n F a c i l i t y , B r o o k h a v e n D o u b l e MP Tandem F a c i l i t y , S u p e r H I L A C / B e v a l a c , and Ho i 1 f i e l d Heavy I o n R e s ea rc h F a c i l i t y ) and o t h e r a c c e l e r a t o r f a c i l i t i e s as j u s t i f i e d b y s c i e n t i f i c demand and t e c h n i c a l f e a s i b i l i t y ; 3 . T o e q u i p e x p e r i m e n t a l a r e a s a t t h e s e f a c i l i t i e s i n o r d e r t o e x p l o i t f u l l y t h e r e s e a r c h c a p a b i l i t i e s o f f e r e d by t h e a v a i l " a b l e beams o f n u c l e a r p r o j e c t i l e s . R e q u i r e m e n t s i n c l u d e m a g n e t i c s p e c t r o m e t e r s , beam t r a n s p o r t l i n e s , h i g h r e s o l u t i o n d e t e c t o r s and o f f - l i n e and o n - l i n e c o m p u t e r - b a s e d d a t a s y s t e m s ; 4 . T o advance r e s e a r c h c a p a b i l i t y 1 n t h i s area by d e v e l o p i n g i mp ro ve d a c c e l e r a t o r beams. T h es e impro veme nt s w o u l d be 1n t h e e n e r g y , i n t e n s i t y , r e s o l u t i o n and v a r i e t y o f beams. 5. To d e v e l o p p h y s i c a l t h e o r i e s a b l e t o d e s c r i b e and t o p r e d i c t p r o p e r t i e s o f n u c l e i and n u c l e a r i n t e r a c t i o n s . T o g u i d e e x p e r i m e n t a l r e s e a r c h a l o n g t h o s e l i n e s t h a t w i l l b e s t t e s t t h e o r y and w i l l be most l i k e l y t o p r o v i d e new i n s i g h t i n t o n u c l e a r phenomena; 6 . T o e s t a b l i s h a p o s i t i o n o f l e a d e r s h i p i n n u c l e a r r e s e a r c h f o r t h e U n i t e d S t a t e s ; and 7 . To i d e n t i f y p r a c t i c a l a p p l i c a t i o n s , p a r t i c u l a r l y t h o s e which r e l a t e t o e n e r g y t e c h n o l o g y , r e s u l t i n g f ro m medium e n e r g y and h ea vy i o n r e s e a r c h s t u d i e s and t o t r a n s f e r t h e s e r e s u l t s t o t h e a p p r o p r i a t e s c i e n t i f i c d i s c i p l i n e o r t e c h n o l o g y . I t s h o u l d be n o t e d t h a t an a p p r e c i a b l e pro gr am o f n u c l e a r r e s e a r c h ( l o w e n e r g y , l i g h t i o n r e s e a r c h ; i s o t o p e s e p a r a t i o n and p r e p a r a t i o n f o r r e s e a r c h u s e ; h e a v y e l e m e n t c h e m i s t r y r e s e a r c h ; d a t a c o m p i l a t i o n and e v a l u a t i o n ; and n e u t r o n and f i s s i o n r e s e a r c h ) 1 s a l s o s u p p o r t e d by t h e D e pa rt m e n t o f E n e r g y 1 n t h e D i v i s i o n o f N u c l e a r S c i e n c e s , O f f i c e o f B a s i c E n e r g y S c i e n c e s . INTRODUCTION BLANK PAGE MEDIUM ENERGY NUCLEAR PHYSICS (HK 03 0 1 ) I n c l u d e s a l l c o s t s a s s o c i a t e d w i t h e x p e r i m e n t a l N u c l e a r P h y s i c s a c t i v i t i e s c a r r i e d o u t a t f a c i l i t i e s w i t h maximum p r i m a r y beam e n e r g y ( p e r n u c l e o n o r e l e c t r o n ) i n e x c e s s o f t h e p i o n p r o d u c t i o n t h r e s h o l d and w i t h p r i m a r y beam p a r t i c l e n o t more m a s s i v e t h a n h e l i u m - 4 . MEDIUM E NE RGY N U CL E A R PHY SI CS - RESEARCH (HK 03 01 0 1 ) I n c l u d e s a l l c o s t s o f n u c l e a r and s u b n u c l e a r r e s e a r c h c a r r i e d o u t w i t h l i g h t i o n s a t f a c i l i t i e s h a v i n g a maximum p r i m a r y beam e n e r g y ( p e r n u c l e o n o r e l e c t r o n ) i n e x c e s s o f t h e p i o n p r o d u c t i o n t h r e s h o l d b u t n o t e x c e e d i n g 1 0 , 0 0 0 MeV. A l s o i n c l u d e s a l l c o s t s o f e x p e r i m e n t a l n u c l e a r and s u b n u c l e a r r e s e a r c h c a r r i e d o u t a t f a c i l i t i e s h a v i n g p r i m a r y beam e n e r g i e s beyond 1 0 , 0 0 0 MeV ( p e r n u c l e o n o r e l e c t r o n ) where t h e i n t e r e s t i s more f o r n u c l e a r s t r u c t u r e s t u d y t h a n f o r e l e m e n t a r y p a r t i c l e s t u d y . BROOKHAVEN NATIONAL LABORATORY Chemistry Department $ 413,000 "Studies of Light Fragment Production and of Pion Interactions" Y. Y. (Thu, J. B. Cumraing, P. E. Haustein, J. Hudis, S. Katcoff, and L. Retnsberg The aim of this work is to understand the fundamental processes involved in the interactions of high energy projectiles with complex nuclei. Studies of these reactions lie at the interface between nuclear physics and elementary particle physics, and they often involve using knowledge from one area to learn something new in the other. Various target elements of low, medium, and high Z are bombarded with protons (800 MeV at LAMPF, 28 GsV at the AGS, and 400 GeV at FNAL), and with mesons (50-500 MeV at LAMPF, greater than 500 MeV at the AGS). Measurements are made of the charges and masoes of the particles produced, and their production cross sections, energy spectra, and angular distributions. As a follow-up to the previous observation that light fragments were ejected from heavy elements preferentially at sideward angles, a two counter-telescope experiment was initiated at the AGS to measure masses of the partners of these fragments. The observed mast, distribution— nearly flat from A s* 20 to 120— , when considered together with the energy spectrum and broad angular correlation, provides strong evidence that many of the light fragments result from multifragment break-up of the target nucleus. Radiochemical studies were also performed which showed that the sideward peaking persists to products with mass A w 100. A study of the spallation of copper by 50- to 350-MeV tt* mesons at LAMPF was completed. The experimental results are in good overall agreement with predictions of a theoretical model (the VEGAS code, developed initially at BNL) which assumes that the production and decay of nucleon isobars are important in determining the energy transferred betwaen an incident pion and a nucleus in this energy region. Similar spallation measurements have been performed with ir~ mesons from the AGS at higher energies (500- to 1570-MeV) which are well above the T ■ 3/2 resonance and which encompass the first T ■ 1/2 resonances in the ir”-nucleon cross section. These studies when combined with the LAMPF work reveal smooth gradual changes of spallation yields toward asymptotic behavior of the type previously observed in proton and heavy-ion reactions. Specific effects of the higher resonances were not observed. Other pion studies seek to obtain cross sections for double charge exchange reactions such as ®̂̂ Bi(Tr+,ir“xn)209-x^t< unique properties of the LAMPF proton beam— its fine time-structure and high current- continue to be exploited to produce, detect, and identify new nuclides in a collaborative experiment. Following the discovery of several new neutron-rich nuclides, both the target and detector system have been changed in order to search for new proton-rich nuclides. Major collaborators: Carnegie-MelLon Univ., LASL, LBL, 0RNL, and Texas A&M Univ. BROOKHAVEN NATIONAL LABORATORY Physics Department $382,000 "Medium Energy Nuclear Structure Probes" H. Palevsky, R. E. Chrien, Morgan May, Rossanna Regget und Richard Sutter Two major efforts are underway. First, a spectrometer has been fabricated at BNL to take advantage of the intense separated K beam available at the Alternating Gradient Synchrotron (AGS) to study "hypernuclel". Tha "hypernucleus" is a new nuclear species created by transforming one of the constituent nucleons into a lambda hyperon, through the (K“, tt“) interaction. The novel features of this new nuclear species come about because the A introduces one unit of the strangeness quantum number into the nucleon orbit.. The A thus moves within the nuclear volume free of the restrictions imposed by the Pauli principle in a normal nucleus. Considerable theoretical interest arises in this because uf the possi­ bility of the strangeness-exchange reactions producing analog states built on the strangeness quantum number much as the isobaric analogs are based on the isopin quantum number. Approximately one half of the approved experiment Z/646 at the AGS has been completed. This work is concerned with the interactions of K“'s with I2C and the emission of of tt***8 associated with formation of the carbon hypernucleus. This first measurement verified that we obtained the expected counting rates and that they were at least an order of magnitude greater than originally pub~ llshed by the Heidelberg Group at CERN. The results also showed that the so-called analog state in carbon is more than a single state and may be a combination of two or three states. We also obtrined angular distributions for the states formed. One of the original aims of doing angular distributions of the emitted -rr's was to identify the orbit in which the A is -formed. From our data we can r eady see that the so-called analog state at 10 MeV excitation is ormed by the ingoing K interacting with p-wave neutrons to form p-wave A hypernucleus, whereas the ground state is formed when the K interacts with a p-wave neutron to form a s-wave hypernucleus. We are now in the process of completing the second half of our experiment Which concerns the formation of 2 hypernuclei in deuterium. In the second effort, the BNL group is a supporter and user of the high resolution proton spectrometer at Los Alamos. The High Resolution Spectrometer (HRS) uses 800-MeV protons to probe nuclear structure by elastic, quaai-elastic, and inelastic scattering of these protons. The first measurement with the HRS spectrometer at Los Alamos was started in FY 1978. This was the measurement of the quasi-free scattering of protons from a series of elements in ascending mass number from Li to Pb. At the high energy end of the spectrum we see evidence of heavier clusters in the nucleus. In particular we identify mass 2 aud mass 4 clusters. Major collaborators: Princeton, MIT, Univ. of Houston, Carnegie-Mellon Univ., Vassar, LASL, UCLA, and Univ. of Texas. " S t u d i e s In P a r t i c l e P h y s i c s " R. P. Haddock and B. M. K. Nefk.ens Re s e a r c h u n d e r t h i s c o n t r a c t c o n t i n u e s t o u mp h a s i z e : (1) e x p e r i m e n t a l t e s t s o f t i me r e v e r s a l i n v a r i a n c e and c h a r g e s ymmet ry ; (2) e x p e r i m e n t a l d e t e r m i n a t i o n o f e l e c t r o m a g n e t i c p r o p e r t i e s o f l o w - l y i n g n u c l e o n r e s o n a n c e s and (3) mea s u r e me n t o f f u n d a m e n t a l n u c l c o n - n u c l e o n and p i o n - n u c l e o n i n t e r ­ a c t i o n p a r a m e t e r s . P r i o r i t y ha s been g i v e n t o a n a l y s i s and p a r t i a l pub­ l i c a t i o n o f r e s u l t s f rom two 1 8 4 - i n c h C y c l o t r o n e x p e r i m e n t s (pp -► ppy a t T,)=730 MeV and v -'p n^py i n t h e A (1232) r e g i o n ) and t o a n a l y s i s f o r LAMPF Expt , #90 "A T e s t o f Time R e v e r s a l I n v a r i a n c e In S i n g l e Pi on P h o t o - P r o d u c t i o n Through A S t ud y o f R e c i p r o c i t y In t h e R e a c t i o n s ti" MeV yT and n+ TVHe3y . " O b j e c t i v e o f t h e pp b r e m s s t r a h l i n g e x p e r i m e n t i s i n f o r m a t i o n on N-N s c a t t e r i n g a m p l i t u d e s i n a r e g i o n where t h e t o t a l c r o s s s e c t i o n h a s a v e r y s t r o n g i n e l a s t i c component . For pho t on e n e r g i e s be low 80 MeV t h e UCLA d a t a a r e i n q u a n t i t a t i v e a g r e e me n t w i t h e x t e r n a l e m i s s i o n domi na nc e mode l s , up b r e m s s t r a h l u n g r e s u l t s c o v e r i n g 18 photon a n g l e s ( o v e r 100 pho t on s p e c t r a ) f o r i n c i d e n t p i o n e n e r g i e s o f 269, 298, and 324 MeV have been s u b m i t t e d t o Phys . Rev. O b j e c t i v e s o f t h i s e x p e r i ­ ment i n c l u d e t e s t o f e x t e r n a l e m i s s i o n dominance and s o f t pho t on a p p r o x ­ i m a t i o n m o d e l s , meas u r emen t o f tip o f f - m a s s - s h e ' l l a m p l i t u d e s , and d e t e r ­ m i n a t i o n o f t h e A m a g n e t i c d i p o l e moment. A f t e r some d i f f i c u l t i e s w i t h t h e o r e t i c a l i n t e r p r e t a t i o n , t h i s t h i r d r e s u l t l ias been a c h i e v e d ! In p a r t i c u l a r , t h i s UCLA e x p e r i m e n t f i n d s 4 . 7 < < 6 , 7 hn i n good a g r e e me n t w i t h SU (6) p r e d i c t i o n s b a f e d on t h e model o f P. Pa s c u a l and R. T a r r a c h ( Nuc l . Phys . B134, 133 ( 1 9 7 8 , ) . O b j e c t i v e s o f LAMPF Expt . 090 a r e : (1 ) mea s u r eme n t o f tT 3H and Ti"3He e l a s t i c s c a t t e r i n g , c h a r g e e x c h a n g e , and r a d i a t i v e c a p t u r e c r o s s s e c t i o n s i n t h e ( 3 , 3 ) r e s o n a n c e r e g i o n ’, (2) t e s t o f m u l t i p l e s c a t t e r i n g t h e o r i e s f o r t h e t h r e e n u c l e o n s ys t e m; and (3) t e s t o f t i me r e v e r s a l i n v a r i a n c e and c h a r g e i nde pe nde nc e s y mm e t r i e s . In t e r ms o f new e x p e r i m e n t s , a s u b s t a n t i a l p o r t i o n o f t h i s u s e r g r o u p ' s e f f o r t s a r e b e i n g d e v o t e d t o LAMPF Expt . 0363 "Measurement o f i n+p E l a s t i c S c a t t e r i n g . " Exp t . 0363 i s d e s i g n e d to o b t a i n a c omp l e t e s e t o f •n±p c h a r g e e x c h a n g e , r a d i a t i v e c a p t u r e , and e l a s t i c s c a t t e r i n g measurement s o v e r t h e 300 t o 600 MeV i n c i d e n t p i o n e n e r g y r a n g e w i t h bo t h p o l a r i z e d and u n p o l a r i z e d t a r g e t s . C e n t r a l o b j e c t i v e i s a r e l i a b l e s e t o f e n e r g y i n d e p e n d e n t and d e p e n d e n t p h a s e s h i f t s . A l s o , t h i s group i s wor k i ng on TRIUMF Expt . 109 - - a mea s u r eme n t o f pd -> 3Hey f o r 400 to 500 MeV i n c i d e n t p r o t o n s t o t e s t t ime r e v e r s a l i n v a r i a n c e . Re c e n t Bonn work on t h e i n v e r s e r e a c t i o n ( y + 3He -► p+d) a r e i n s i g n i f i c a n t d i s a g r e e m e n t w i t h p r e v i o u s l y a c c e p t e d Ca l , Tech d a t a . Th-, Cal Tech d a t a a g r e e w i t h e x i s t i n g p+d -* 3He+y d a t a ; t h u s t h e new, more a c c u r a t e r e s u l t s r a i s e t h e p o s s i b i l i t y o f a v i o l a t i o n o f t i me r e v e r s a l i n v a r i a n c e . U N IV E R S IT Y 0 I: C A L IFORNIA AT LOS ANG ELES......................................................................... $ 2 6 9 ,2 4 5 P h y s T c s ’ D e p a r t m e n t Major c o l l a b o r a t o i >: -10- C A R N E G I F - M E L L O N U N I V E R S I T Y , ........................................................................................................................ $ 2 9 9 , 8 0 0 P h y s ic s Departm ent " E x p e r i m e n t a l N u c l e a r P h y s i c s a t Medium E n e r g i e s w i t h P i o n s and Kaons" P . D . B a r n e s , ft. A . E 1 s e n s t e 1 n , and W. R . Wharton A t t h e p r e s e n t t i me r e s e a r c h wo r k under t h i s c o n t r a c t e mp ha si z es e x p e r i m e n t a l I n v e s t i g a t i o n s o f t h e r e a c t i o n mechanisms t h r o u g h w h ic h p i o n s and kaons I n t e r a c t w i t h n u c l e i . H o w e v e r , 1 t r emai ns t h e l o n g ­ t er m goal o f ' t h i s g ro up a l s o t o use meson p ro be s t o e x t r a c t new and un iqu e i n f o r m a t i o n on n u c l e a r s t r u c t u r e . C u r r e n t a c t i v i t i e s I n c l u d e : LAMPF E x p t . #246 " S t u d i e s o f n f S c a t t e r i n g a t 50 MeV f ro m L i g h t N u c l e i " . A l l r e s u l t s have been s u b m i t t e d f o r p u b l i c a t i o n . These a n g u l a r d i f f e r e n t i a l c r o b s s e c t i o n d a t a c l e a r l y I n d i c a t e t h a t some o f t h e more s i m p l e t h e o r e t i c a l d e s c r i p t i o n s u s i n g f r e e u - n u c l e o n a m p l i t u d e s a r e i n a d e q u a t e t o d e s c r i b e q u a n t i t a ­ t i v e l y i t - n u c l e u s s c a t t e r i n g . LAMPF E x p t . # 1 9 1 % + - N u c l e u s I n e l a s t i c S c a t t e r i n g t o G i a n t R e s o n a n c e s " . The o b j e c t i v e 1s t o s ea r c h f o r e x c i t a t i o n c g i a n t n u c l e a r r es o n a nc e s i n p l o n - n u c l e u s s c a t t e r i n g . The r e l a t i v e l y low mass and h i g h 1s o s p1n o f t h e p i o n , as compared t o more c o n ­ v e n t i o n a l p and a p ro be s o f g i a n t r e s o n a n c e s , p ro mi ses i n t e r e s t ­ i n g r e s u l t s . L a r g e bumps 1 n t h e e n e r g y s p e c t r a o f Mg, C a , N 1 , and Cu between 10 and 20 MeV h ave been o b s e r v e d as a f u n c t i o n o f s c a t t e r i n g a n g l e f o r I n c i d e n t p i o n e n e r g i e s o f 67 MeV. LAMPF E x p t . #23 "A S u r v e y o f P 1 o n - N u c l e u s E l a s t i c and I n e l a s t i c S c a t t e r i n g § t 180 M e V " . A n g u l a r d i s t r i b u t i o n s f o r e l a s t i c and I n e l a s t i c it and v~ s c a t t e r i n g have been a c cu m u l a t e d f o r t a r & e t s o f 89Y , 92Mo and 1 I 8S n . T h e a n g u l a r r an ge s t u d i e d was 1 5 ° s e s 1 0 0 ° , C a r e f u l e x a m i n a t i o n o f t h e ir+/ V r a t i o s f o r I n e l a s t i c s c a t t e r i n g h o p e f u l l y w i l l l e a d t o i n f o r m a t i o n a b o u t t h e e x t e n t t o wh ic h l o w - l y i n g I n e l a s t i c e x c i t a t i o n s i n t h e s e n u c l e i can be d e s c r i b e d i n t erms o f v a l e n c e n e u t r o n s o r p r o t o n s . AGS E x p t . #646 " S t u d i e s o f t h e ( K “ ,tr“ ) R e a c t i o n " . T he kaon s p e c t r o m e t e r a t BNL has been c o mp l e te d and s u c c e s s f u l l y t e s t e d o n - l i n e . C M l H e v e l o p e d w i r e chambers a r e a p a r t o f t h i s a p p a r a t u s . U s e f u l d a t a f o r t h e ^ 2C ( K “ , t T ) ^ C r e a c t i o n has been a c c u m u la te d and 1s b e i n g a n a l y z e d . I n a d d i t i o n , t h e r e a c t i o n K’ +d + E ' + u + n ( s p e c t a t o r ) has been e x a m i n e d . F u r t h e r wo r k on b ot h o f t h e s e s t u d i e s w i l l t a k e p l a c e 1n t h e n e a r f u t u r e . AGS E x p t . #692 "Measurement o f K * E l a s t i c S c a t t e r i n g From S e l e c t e d N u c l e i a t 650 t o 1000 M e V / c " . The o b j e c t i v e 1 s d e t e r m i n a t i o n o f k a o n - n u c l e u s e l a s t i c s c a t t e r i n g p a r a m e t e r s . These d a t a w i l l be t h e f i r s t p r e c i s i o n measurements o f t h i s t y p e and w i l l i n c l u d e a n g u l a r d i s t r i b u t i o n s . M a j o r c o l l a b o r a t o r s : U n i v . o f C o l o r a d o , New M e xi c o S t a t e U n i v . , L A S L , C o l l e g e o f W i l i l a i n and M a r y , U n i v . o f Wyoming, Cat T e c h , U n i v . o f W a s h i n g t o n , U n i v . o f W i s c o n s i n , B N L , and U n i v . o f H o u s t o n . .11. CARNEGIE-MELLON UNIVERSITY................................ $ 33,000 Chemistry Department "Experimental Nuclear and Radiochemistry" P. J. Karol This endeavor entails the investigation of deep nuclear spallation reactions induced by high-energy light particles on cwiplex nuclei. Experimental studies involve activation of various medium to heavy mass targets bombarded by pi-mesons, protons *nd alpv i particles. A variety of radiochemical and radiometric technique* are employed to quantify the product yield spectrum with particular amphasis being placed on spallation products far from yield maxima. Necessarily these involve radioisotopes of short half-life and Low yield so that rapid radiochemical techniques are being developed and employed. Irradiations are performed predominantly at the Clinton P. Anderson Los Alamos Meson Physics Facility although occasional use of other facilities such as Argonne, Brookhaven, Bevelac or SREL prove valuable. Botpbairdments of several medium mass target elements with 190 MeV , 800 MeV protons and 28 GeV protons have been executed. Theoretical modifications to the cascade and evaporation phases of the high-energy nuclear reaction mechanism will be examined at a fairly fundamental level. The initial theoretical thrust will be directed at the evaporative behavior of very high-temperature nuclei and how such bohavior might become evident in spallation processes. Major collaborators: No major collaborators to date. I -12- CASE WESTERN RESERVE UNIVERSITY . ............................. $165,000 Physics Department "Studies of the Spin Dependence of Proton-Proton Interactions" H. B. Willard, P, R. Bevington, and H. W. Baer Our LAMPF Users group is continuing the investigation of the proton-proton interaction by the method of polarized beaus and polarized targets. Triple scattering and initial state spin correlation parameters are being measured. This series o* experiments is intended to shed light on the strong nuclear force, the spin dependence of the interaction, and symmetries involved. Polarization in p-D elastic scattering is under study. Asytiimotries in pion production produced by a polarized proton beam and liquid hydrogen target are planned to be investigated. In addition, we plan to investigate few nucleon systems by observing u° particles in the final state. Support­ ing instrumentation and techniques are part of the program. Single and double pion momentum spectra have been observed for pp collisions at 800 MeV. Total reaction cross sections on carbon, three calcium isotopes, and lead have been measured. The polarization analyzing power of proton-proton elastic scat­ tering at 428, 643, and 796 MeV has been studied. Results for the Ayy(u) spin correlation parameter in p-p elastic scattering have been obtained at 643 and 796 MeV. Progress on the n° spectrometer continues. Major collaborators: Los Alamos Scientific Laboratory University of Idaho -15 - "Meson P r o d u c t i o n and R e a c t i o n s a t Medium E n e r g i e s • B . W. Mayss I I , E . V , H u n g e r f o r d I I I , and J . C . A l l r e d T h i s g r o u p has been c o n d u c t i n g e x p e r i m e n t a l i n v e s t i g a t i o n s o f p i o n - n u c l e u s i n t e r a c t i o n s 1n t h e ( 3 , 3 ) r e s o n a n c e r e g i o n and o f p i o n p r o d u c t i o n 1n p r o t o n - ( f e w n u c l e o n s y s t e m ) c o l l i s i o n s . T h e s e s t u d i e s a r e b e i n g e x t e n d e d t o k a o n - n u c l e u s i n t e r a c t i o n s . D at a t a k i n g i s c o m p l e t e , aRd a n a l y s i s and j o u r n a l p u b l i c a t i o n w o r k 1s un de r way f o r : L A MP F E x p t . #80 “ F o r w a r d E l a s t i c S c a t t e r i n g o f * + and it" f r o m 13C , ^ 0 , ^ C a , 2 ° eP b " . T h e s e s t u d i e s e m p h a s i z e a m p l i t u d e s f r o m C o u l o m b - n u c l e a r i n t e r f e r e n c e d a t a and t o t a l c r o s s ' - s e c t i o n d a t a . A l s o , i t * d a t a on !+0Ca and If8Ca were t a k e n t o examine d i f f e r e n c e s 1n n e u t r o n and p r o t o n m a t t e r r a d i f . LAMPF E x p t . #81 " S t u d y o f N e u t r o n - P r o t o n and P r o t o n - P r o t o n C o i n c i d e n c e S p e c t r a f ro m p +d * n+ p+p R e a c t i o n " . T h e s e k i n e m a t i c a l l y c o m p l e t e e x p e r i m e n t s p r o v i d e b o t h q u a s i - f r e e s c a t t e r i n g d a t a and f i n a l s t a t e I n t e r a c t i o n d a t a t o t e s t S i m p l e I m p u l s e A p p r o x i m a t i o n , S p e c t a t o r M o d e l , and F i n a l S t a t e I n t e r a c t i o n t h e o r e t i c a l d e s c r i p t i o n s o f p+d s c a t t e r i n g as w e l l as t o p r o v i d e b a s i c n uc' leon- n uc l eo r , i n t e r a c t i o n d a t a . LAMPF E x p t . #1 97 " I n v e s t i g a t i o n o f t h e Ch ar ge Sy mme t ri c R e a c t i o n s p + d * 3He+ir° and p + d >3H+ir T h i s work p r o v i d e s k i n e m a t i c a l l y c o m p l e t e d a t a on t h e i m p o r t a n t ( p , i r ) r e ­ a c t i o n 1n a r e l a t i v e l y s i m p l e n u c l e a r s y s t e m . C u r r e n t w or k e mp ha si z e s p i o n p r o d u c t i o n r e s e a r c h a t LAMPF and I n i t i a t i o n o f k a o n - n u c l e u s d a t a t a k i n g a t A G S . I n p a r t i c u l a r , wo r k a t t h e AGS w i l l i n c l u d e : AGS E x p t . #646 " H y p e r n u c l e a r S p e c t r o s c o p y o f S t a t e s Formed b y t h e C o h e r e n t I n t e r a c t i o n g f K w i t h N u c l e i " . A n g u l a r d i s t r i b u t i o n s f o r t h e ( K “ , n “ ) r e a c t i o n w i l l be t a k e n w i t h P a l e v s k y ' s e n e r g y l o s s s p e c t r o m e t e r s y s t e m . AGS E x g t . _ # 7 2 8 S e a r c h f o r a EN bound s t a t e by o b s e r v i n g t h e ( K , 7r” ) r e a c t i o n on 2H . AGS E x p t . #692 "The Measurement o f t h e K1 E l a s t i c S c a t t e r i n g From S e l e c t e d N u c l e i A t ^ 0 0 M e V / c " . The o b j e c t i v e i s d a t a on g l o b a l o p t i c a l p o t e n t i a l p a r a m e t e r s f o r { ( - nu cl eus s c a t t e r i n g ; t e n t a t i v e t a r g e t s a r e C and C a . M a j o r c o l l a b o r a t o r s : R 1 c e U n i v e r s i t y , Case We st e r n R e s er v e U n i v e r s i t y , L A S L , B N L , P r i n c e t o n , V a s s a r , K I T , and C a r n e g l e - M e l l o n . UN’i VERS ITY OF HOUSTON....................... ............................................ $160,000 D e p a r tm e n t -16 - " N u c l e a r L e v e l - S c h e m e s S t u d i e s U t i l i z i n g LAMPF and U N I S O R ” R . L . H e a t h , R , C . G r e e n w o o d , R . G . H e l m e r and C . W. R e i c h T h i s p ro gr am has as o b j e c t i v e s t h e g e n e r a t i o n o f new n u c l e a r - s t r u c t u r e d a t a on n u c l i d e s f a r o f f t h e l i n e o f s t a b i l i t y and the c h a r a c t e r i z a t i o n and I n t e r p r e t a t i o n o f t h e s e d a t a t o t e s t c u r r e n t t h e o r i e s and d e v e l o p new c o n c e p t s . T he s e a r e impl ement ed t h r o u g h s t u d y o f t h e r a d i a t i o n s a m l t t e d 1 n t h e decay o f n e u t r o n - d e f i c i e n t n u c l i d e s . T h e p r i m a r y means f o r p r o d u c i n g t h e s e n u c l i d e s a r e p r o t o n - i nd u ce d r e a c t i o n s on L A MPK . Work has c o n t i n u e d on t h e decay schemes o f 1S0Tb and l 51T b , n e a r t h e N-v 90 r e g i o n where t h e t r a n s i t i o n to s t r o n g l y d ef or me d e q u i l i b r i u m n u c l e a r shapes t a k e s p l a c e . The a n a l y s i s o f e x t e n s i v e y -y c o i n c i d e n c e d at a on 15C>Tb was c o m p l e t e d and t h e m a j o r f e a t u r e s o f t h i s complex ( Q e ^ 4 . 7 MeV) d e : a y scheme were e s t a b l i s h e d . P a r t i c u l a r a t t e n t i o n was f o c u s e d on t h a t p o r t i o n o f t h e 1S0Gd l e v e l scheme l y i n g w i t h i n ^ 0 . 6 MeV o f t h e Q - v a l u e . The l a c k o f s u i t a b l e p r e c i s e Y-ray e n e r g y - c a l i b r a t l o n s t a n d a r d s 1n t h e e n e r g y r e g i o n near 4 . 5 MeV hampered t h i s s t u d y . T o h e l p a l l e v i a t e t h i s d e f i c i e n c y , p r e c i s e e n e r g y v a l u e s were measured f o r t h e 4 7 4 2 - and t h e 4 8 5 2 - keV y r a y s f ro m t h e decay o f 8 eR b . I n a d d i t i o n , I n v o l v e m e n t 1n t h e p r opo se d e f f o r t t o p r od uc o r a d i o a c t i v e sampl es 1n t h e LAMPF beam dump t o s e r v e as t a r g e t s f o r c h a r g e d - p a r t l c l e - Induced r e a c t i o n s p e c t r o s c o p y c o n t i n u e d t h i s f i s c a l v e a r . A number o f d i s c u s s i o n s w er e h e l d w i t h i n t e r e s t e d p e r s o n n e l f ro m L A S L and o t h e r l a b o r a t o r i e s i n o r d e r t o d e t e r m i n e t h e scope o f such a p r o g r a m . M a j o r c o l l a b o r a t o r s : L o s Alamos S c i e n t i f i c L a b o r a t o r y {M. E . B u n ke r ) IDAHO NUCLEAR ENGINEERING LABORATORY ............................ ...........................$ 16,000 -17- JOHNS H O P K I N S U N I V E R S I T Y ..................................................................................................... ........................................... $ 5 0 , 0 0 0 " N u c l e a r Moments and N u c l e a r S t r u c t u r e " L . M a d a n s k y , Y . K . L e e , and J . C . W a l k e r We have u n d e r t a k e n a p r o j e c t t o measure a c c u r a t e l y ( t o a b o u t 5 ppm) t h e p i o n i c x - r a y e n e r g i e s o f l i g h t e l e m e n t s such as S 1 , P , T i 1n o r d e r t o d e t e r m i n e t h e p l o n i c mass t o e q ua l p r e c i s i o n . I n t h e c o u r s e o f w o r k , we a r e a l s o e x p l o r i n g t h e q u e s t i o n s o f t h e c o r r e c t n e s s o f t h e c a l c u l a t i o n s o f t h e vacuum p o l a r i z a t i o n , t h e s t r o n a i n t e r a c t i o n e f f e c t s and t h e e l e c t r o n s c r e e n i n g c o r r e c t i o n s 1n t h e p H <c x - r a y l i n e e n e r g i e s . We a l s o a r e p u r s u i n g a s t u d y o f h^gh s p i n , c l e a r s t a t e s i n du ce d by p i o n c a p t u r e . O u r work on "-autron-gamma c o i n c i d e n c e s t u d i e s f o l l o w i n g n e g a t i v e p i o n c a p t u r e i n t a n t a l u m and holmlum we r e p a r t i a l l y c o m p l e t e d a t N e v i s S y n c h r o t r o n . The r e s u l t s show a s t r i k i n g c o r r e l a t i o n b et ween n e u t r o n e n e r g y and n e u t r o n m u l t i p l i c i t y . We p r o p o s e t o c o n t i n u e the p ro gr am a t o t h e r s u i t a b l e a c c e l e r a t o r s . Some f u t u r e e x p e r i m e n t s a r e a l s o b e i n g p la nn e d f o r n u c l e a r e x c i t a t i o n s t u d i e s f o l l o w i n g K-meson c a p t u r e . M a j o r c o l l a b o r a t o r s : J . D u g a n , C . S . Wu C ol umb ia U n i v e r s i t y D . L u Y a l e U n i v e r s i t y -20- LAWRENCE BERKELEY LABORATORY R e c e n t a c c o m p l i s h m e n t s i n c l u d e : 1 . H e s o n i c Atoms T h e a b s o r p t i o n c o e f f i c i e n t o f k a o n i c p o t a s s i u m x - r a y s has been measured i n e r b i u m f o r t h e t r a n s i t i o n n * 6 -*■ 5 . T h e se x - r a y s f a l l on t h e e r b i u m K- ed g e w h i c h a l l o w s us t o a c c u r a t e l y d e t e r ­ mine t h e i r e n e r g y . The n e g a t i v e kaon mass can be c a l c u l a t e d f ro m t h e x - r a y e n e r g y . I n c o o p e r a t i o n w i t h t h e U n i v e r s i t y o f V i c t o r i a g r o u p a t T P . I U M F , t h e p l o n i c x - r a y i n t e n s i t i e s o f 60 chemi ca l e l e m e nt s have been m e a s u r e d . 2 . I n v e s t i g a t i o n s on t h e S t r u c t u r e o f L i g h t N u c l e i Work has c o n t i n u e d on d a t a a n a l y s i s and p u b l i c a t i o n o f r e s u l t s f ro m o u r e a r l i e r measurements o f f o r w a r d e l a s t i c s c a t t e r i n g 1n t h e p-**He s y s t e m a t ( e q u i v a l e n t ) p r o t o n e n e r g i e s o f 0 . 4 , 1 . 0 5 , 2 . 6 8 , and 4 . 8 9 G e V . The s t u d y o f f o r w a r d e l a s t i c s c a t t e r i n g has been e x t e n d e d t o i n c l u d e measurements o f p - 3He a t 2 . 6 8 G e V . ( 0 . l < t < 0 . 7 6 ) , and d - d a t 4 . 1 8 GeV ( 0 . 0 8 < t < 2 . 0 9 ( G e V / c 2 ) ) , I n a c o l l a b o r a t i v e e x p e r i ­ ment a t A N L , measurements we r e made o f : 1 ) p o l a r i z a t i o n i n e l a s t i c p - p and p - n s c a t t e r i n g a t 1 . 0 3 G e V. The p - n measure ment s a r e t h e f i r s t t o be done i n t h i s e n e r g y r a n g e , and 2 ) p o l a r i z a t i o n i n b a c k ­ ward e l a s t i c p - d s c a t t e r i n g a t 0 . 6 8 , 1 . 0 3 , and 1 . 5 3 G e V . An e x t e n s i o n o f t h i s pro gr am w i l l p e r m i t measurement o f f o r w a r d and backward e l a s t i c p - d s c a t t e r i n g u s i n g A N L 1 s p o l a r i z e d d e u t e r o n beam t o s t u d y t h e D - s t a t e and N * components o f t h e d e u t e r o n wave f u n c t i o n . 3 . R a d i a t i v e P1 on C a p t u r e , P i o n S c a t t e r i n g and Muon Decay W i t h an i m p r o v e d , h i g h r e s o l u t i o n , p a i r - s p e c t r o m e t e r t h e t r i t i u m Y - s p e c t r u m r e s u l t i n g f r o m p i o n c a p t u r e has been d e t e r m i n e d w i t h g r e a t l y i m p r o v e d a c c u r a c y . P r e l i m i n a r y r e s u l t s , w i t h a f a c t o r o f 10 more good e v e n t s t h a n e a r l i e r w o r k , a r e i n b a s i c agr ee me nt w i t h t h e e a r l i e r e f f o r t . H o w e v e r , we see no e v i d e n c e f o r a p o s s i b l e bound s t a t e o f 3 n e u t r o n s . Co mp l et e a n a l y s i s o f t h e d a t a w i l l a l l o w much more a c c u r a t e n u c l e o n s t r u c t u r e c o n s t a n t s t o be e x t r a c t e d f o r com­ p a r i s o n w i t h t h e o r y o f t h e t h r e e - b o d y s y s t e m . 4 . A N e u t r i n o E x p e r i m e n t t o T e s t Muon C o n s e r v a t i o n A n e x p e r i m e n t a l s t u d y o f t h e n a t u r e o f n e u t r i n o s f r o m muon d e c a y i s un de r way a t L A M P F . The e x p e r i m e n t i s d e s i g n e d t o d i s t i n g u i s h between an a d d i t i v e and a m u l t i p l i c a t i v e muon c o n s e r v a t i o n l a w . M a j o r c o l l a b o r a t o r s : U C L A ( G . I g o ) , U n i v e r s i t y o f M i n n e s o t a (M. M a r s h a k ) , A N L ( R . K l e m ) , U n i v e r s i t y o f V i c t o r i a ( R . P e a r c e ) , CERN ( C . S a b e v ) , C e n t r a l W a s h i n g t o n U n i v e r s i t y (W. C . S p e r r y ) , Or egon S t a t s U n i v e r s i t y ( A . S t e t z ) , U n i v e r s i t y o f T o k y o (M„ K o i k e ) , I KO Amsterdam ( A . W a p s t r a ) , L A S L ( H . B a e r ) , U n i v e r s i t y o f Z u r i c h ( P . T r u o l ) , S I N ( G . S t r a s s n e r ) . -2i- " P r e c i s i o n , H 1 g h - R e s o l u t i o n E l e c t r o n S c a t t e r i n g a t t h e Ba te s L i n a c " B . L . Berman The a v a i l a b i l i t y o f t h e B a t e s H n a c and t h e e n e r g y - l o s s s p e c t r o ­ m e t e r t h e r e makes p o s s i b l e e l e c t r o n - s c a t t e r i n g measurements o f a p r e c i s i o n n o t p o s s i b l e h e r e t o f o r e , and t h u s opens new v i s t a s 1n t h e f i e l d and c r e a t e s t h e o p p o r t u n i t y f o r o b t a i n i n g and e x ­ p l o i t i n g a new g e n e r a t i o n o f e l e c t r o n - s c a t t e r i n g d a t a . L L L and M I T have begun a s e r i e s o f c o l l a b o r a t i v e e x p e r i m e n t s wh ic h i n v o l v e t h e use o f t h e c he m i ca l and m e t a l l u r g i c a l c a p a b i l i t i e s o f L L L t o m a n u f a c t u r e t h i n p r e c i s i o n s c a t t e r i n g t a r g e t s f o r use a t t h e B a t e s f a c i l i t y , We have p e r f o r m e d such measurements on the i m p o r t a n t r a r e I s o t o p e s o f o x y g e n . We hope t o c o n t i n u e t h e s e s t u d i e s , and t o e x t e n d them t o t h e r a r e s i l i c o n I s o t o p e s . T h i n t a r g e t s o f B e O , e n r i c h e d 1n 1 7 0 a n d / o r 18 0 , were m a n u f a c t u r e d a t L L L ( f r o m H 20 s a m p l e s ) , and e l e c t r o n - s c a t t e r i n g d a t a have been o b t a i n e d a t B a t e s 1n 1 9 7 6 and 1 9 7 7 . A l s o , new BeO t a r g e t s , s y n t h e s i z e d f ro m h i g h l y e n r i c h e d ( ^ 9 0 % ) 170 g a s , have been m a n u f a c t u r e d a t L L L f o r use 1n s e v e r a l measurements s c h e d u l e d f o r 1 9 7 8 - 7 9 , i n c l u d i n g 1 8 0 ° e l e c t r o n s c a t t e r i n g a t B a t e s w i t h t h e new magnet s y s t e m t h e r e . T h i n S i O * t a r g e t s , u s i n g m a t e r i a l e n r i c h e d t o 95% i n t h e r a r e I s o t o p e s 29Si and 30S i > a r e now b e i n g m a n u f a c t u r e d a t L L L . The f i r s t i m p o r t a n t r e s u l t s on t h e oxy ge n i s o t o p e s now have been s u b m i t t e d f o r p u b l i c a t i o n . T he s e i n r l u d e ( a ) t h e p r e c i s i o n measurement o f t h e c h a r g e d i s t r i b u t i o n s f o r 170 and 10O wh ic h showed t h a t , w h e r e ­ as t h e c h a r g e d i s t r i b u t i o n f o r 170 i s a l m o s t i d e n t i c a l t o t h a t f o r 160 , t h e c h a r g e d i s t r i b u t i o n f o r 180 i s s u b s t a n t i a l l y l a r g e r ; t h a t 1s , a d d in g a s i n g l e v a l e n c e n e u t r o n t o a 160 c o r e h a r d l y p e r t u r b s t h e p r o t o n d i s ­ t r i b u t i o n t h e r e i n , b u t a d d i n g a p a i r o f ( v a l e n c e ) n e u t r o n s causes a s t r o n g r e a r r a n g e m e n t o f t h e p r o t o n s - a r e s u l t w h ic h was f o r es ha do w ed by o u r e a r l i e r p r o t o n - s c a t t e r i n g measurements a t I n d i a n a ; and ( b ) t h e d i s c o v e r y , v i a t h e b a c k - a n g l e e l e c t r o n - s c a t t e r i n g measurements a t Ba t es o f t h e ma gne t- 1 z a t 1 o n - d e n s 1 t y d i s t r i b u t i o n f o r l 70 , t h a t t h e M3 component was s u p p r e s s e d t o a d e g re e f a r beyond t h e a b i l i t y o f any t h e o r y t o e x p l a i n , and t h a t t h e h i g h - m o m e n t u m - t r a n s f e r s i d e o f t h e M5 component was s i m i l a r l y e n h a n c e d ; t h i s r e s u l t i s c o m p l e t e l y new and as y e t we know o f no p h y s i c a l mechanism c a p a b l e o f p r o d u c i n g such e f f e c t s , t h u s showi ng t h a t more t h e o r e t i c a l e f f o r t i s needed on a s u b j e c t h e r e ­ t o f o r e t h o u g h t t o be w e l l u n d e r s t o o d . M a j o r c o l l a b o r a t o r s : MI T LAWRENCE LIVERMORE LABORATORY........................................................... $ 25,000 -2 2 - " N u c l e a r and P a r t i c l e P h y s i c s R e s e a r c h " L . R o s e n , D. N a g l e , L . A g n e w , 0 . Amann, D . Bowman, R . Bur man, D. C o c h r a n , P . C h a m b e r l a i n , M. C o o p e r , J , f-'rarik, P . G r a m , C . H o f f m a n , G , H o f f m a n , R . M a c e k , R . M i s c h k e , C. M o r r i s , J . P o t t e r , R . R e d w i n e , J . S p e n c e r , N . T a n a k a , and H . T h l e s s e n T h i s t a s k c o v e r s t h e b a s i c r e s e a r c h a c t i v i t i e s o f t h e Me d iu m - E n e r g y P h y s i c s D i v i s i o n p e r s o n n e l a t L A M P F , n a m e l y , I n v e s t i g a t i n g t h e p r o p e r t i e s o f n u c l e i and p a r t i c l e s and t h e i r s t r u c t u r e and i n t e r a c t i o n s , p a r t i c u l a r l y 1n t h e me d i u m- en erg y r e g i o n . T h i s i s t h e s c i e n t i f i c b a s i s o f t h e LAMPF p r o j e c t . T h e r e a r e v e r y few u s e r g ro up s wh ic h a r e c o m p l e t e l y s e l f - s u f f i c i e n t . Many o f them have r e s i d e n t g r a d u a t e s t u d e n t s and p o s t d o c t o r a l f e l l o w s who need some h e l p and g u i d a n c e . The LAMPF r e s i d e n t s t a f f p r o ­ v i d e s g u i d a nc e and s u p p o r t f o r t h e s e a c t i v i t i e s . T h ey a l s o c a r r y o u t t h e i r own r e s e a r c h p r o g r a m . L A S I. i n c o l l a b o r a t i o n w i t h U n i v e r s i t y o f C hi ca g o and S t a n f o r d U n i v e r s i t y has c omp le t ed a new s e a r c h f o r t h e r a r e decay y + e y . T he s c i e n t i f i c i n t e r e s t i n t h i s s e a r c h i s c o n n e c t e d w i t h t h e e x t r a o r d i n a r y r e c e n t s u cce ss e s o f gauge t h e o r i e s i n u n i f y i n g t h e weak and e l e c t r o m a g n e t i c I n t e r a c t i o n s , i n p r e d i c t i n g weak n e u t r a l c u r r e n t s , e t c . A p r e d i c t i o n wh ic h has n o t been v e r i f i e d i s t h a t t h e p h y s i c a l muon w i l l n o t be a pur e quantum s t a t e , b u t w i l l have an a d m i x t u r e o f muon and e l e c t r o n number; and hence t h e d ec ay u+ey can p ro ceed a t some ( v e r y s m a l l ) r a t e . I n t e r e s t was a l s o h e i g h t e n e d by a p re ma tur e r e p o r t f ro m t h e Swiss I n s t i t u t e f o r N u c l e a r S t u d i e s a y e a r ago t h a t t h e d ec ay had a c t u a l l y been o b s e r v e d a t a l e v e l o f two p a r t s i n a b i l l i o n . L A S L t h e r e u p o n u n d e r t o o k t o r e p e a t t h e e x p e r i m e n t w i t h t e n t i m e s more s e n s i t i v i t y , n a m e l y , one p a r t i n t e n b i l l i o n , and has by now a c h i e v e d t h i s g o a l . As s u c h , i t i s t h e most s e n s i t i v e y d ec ay e x p e r i m e n t e v e r c o m p l e t e d . The i mprovement was made p o s s i b l e b y t h e i n t e n s e beams a t L A M P F , whi ch p r o v i d e d more d ec ay s t o e x a m i n e , p l u s more p r e c i s e methods o f r e j e c t i n g s p u r i o u s e v e n t s . No such decays have been o b s e r v e d . ( T h e S wi ss have now p u b l i s h e d t h e i r r e s u l t , and see no bona f i d e e v e n t s , b u t a t a l e v e l t w e n t y t i m es l e s s s e n s i t i v e t h a n t h e L A S L - C h i c a g o - S t a r i f o r d r e s u l t . ) The p r e s e n t r e s u l t r u l e s o u t c e r t a i n c l a s s e s o f gauge m o d e l s , b u t most models s t i l l p r e d i c t t h e e f f e c t a t some l e v e l . LAMPF and S t a n f o r d a re c o n s i d e r i n g how a f u r t h e r improvement o f a hundred i n s e n s i t i v i t y may be a c h i e v e d . T h i s a p p e a r s t o be p o s s i b l e . A p p r o x i m a t e l y 100 e v e n t s f ro m t h e r e a c t i o n v e+0>-p+p+e" have been o b s e r v e d i n an e x p e r i m e n t u s i n g t h e n e u t r i n o s c r e a t e d 1n t h e LAMPF beam s t o p . T h i s r e s u l t was p a r t o f an o n - g o i n g s t u d y o f l e p t o n - n u m b e r c o n s e r v a t i o n by a gro up o f p h y s i c i s t s f r o m L A S L , Y a l e and Bern U n i v e r s i t i e s , L B ! . , N R C - O t t a w a , and S a c l a y . I n t h e l e p t o n - n u m b e r c o n s e r v a t i o n e x p e r i m e n t , t h e t y p e o f n e u t r i n o o m i t t e d 1n muon -d e ca y i s d e t e r m i n e d f r o m n e u t r i n o I n t e r a c t i o n s i n a l a r g e w a t e r C e r e n k o v d e t e c t o r . F o r t h e measurement o f t h e v e+D r e a c t i o n — t h e i n v e r s e o f t h e " p e p " r e a c t i o n t h a t o c c u r s 1 n t h e s o l a r e n e r g y c y c l e — t h e C e r e nk o v d e t e c t o r was f i l l e d w i t h 6 .6 t o n s o f h e a v y w a t e r . C o m p l e t e l y s u r r o u n d i n g t h e d e t e c t o r was a c osmic r a y a n t i - c o i n c i d e n c e s h i e l d , composed o f a s andwi ch o f p l a s t i c s c i n t i l l a t o r s , l e a d s h i e l d i n g , and d r i f t c h am b e rs , w hi ch reduced c os m i c r a y e v e n t s by a LOS ALAMOS S C IENTIFIC LABORATORY .................................................... $2,060,000 RFOTvls'ion LOS ALAMOS SC IE NTIF1C LABOk TORY MF*DT7TsTo7i $453,000 " P r a c t i c a l A p p l i c a t i o n s R e s e a r c h a t L A H P F " J . B r a d b u r y , K. H a n s o n , A . H a r v e y , R . H e f f n e r , M. L e o n , and M. S c h i l l a c i C u r r e n t a p p l i e d r e s e a r c h p ro gr ams a t L A MP F I n c l u d e : s o l i d - s t a t e p h y s i c s and m a t e r i a l s a n a l y s i s ( m u o ns , p r o t o n s , n e u t r o n s ) , c h em i c a l e f f e c t s on meson c a p t u r e ( m u o n s ) , r a d i o i s o t o p e p r o d u c t i o n (beam s t o p p r o t o n s ) , r a d i a t i o n b i o l o g y and c a n c e r t h e r a p y ( p i m e s o n s ) , r a d i a t i o n damage s t u d i e s ( p r o t o n s , n e u t r o n s ) , D O D - r e l a t e d s t u d i e s ( p u l s e d n e u t r o n s ) , and e l e c t r o n u c l e a r f u e l b r e e d i n g f e a s i b i l i t y e x p e r i m e n t s . M u o n - S p i n R o t a t i o n ( u S R ) R e s e a r c h M u o n d e p o l a r i z a t i o n measure ment s as a f u n c t i o n o f t e m p e r a t u r e ha ve been made f o r a number o f samples i n c l u d i n g A 1 , C u , V , and N b , some doped w i t h known q u a n t i t i e s o f i m p u r i t i e s . T h e r e s u l t s i n d i c a t e t h a t a t l o w t e m p e r a t u r e s i n Cu t h e muons a r e c l e a r l y l o c a l i z e d a t o c t a h e d r a l i n t e r s t i t i a l s i t e s b u t s u r p r i s i n g l y . . . t h i s b e h a v i o r 1 s n o t o b s e r v e d i n A 1 . By v a r y i n g i m p u r i t y c o n c e n t r a t i o n s 1n V and N b , i t was a s c e r t a i n e d t h a t even a t low t e m p e r a t u r e ( l O ^ K ) muon d e p o l a r i z a t i o n i s d o m i n a t e d by t r a p s a s s o c i a t e d w i t h i m p u r i t i e s . D i f f u s i o n s t u d i e s u s i n g uSR a r e u n d e r w a y w h i c h may i mp ro ve o u r u n d e r s t a n d i n g o f h y d r o g e n d i f f u s i o n i n m e t a l s . P r o t o n Computed T omography R e s i d u a T e n e r g y measurements on a n e a r l y m on oc hr om a ti c 200 MeV p r o t o n beam p a s s i n g t h r o u g h an inhomogeneous sampl e f r o m a number o f d i r e c t i o n s have been us ed t o o b t a i n t h e d e n s i t y d i s t r i b u t i o n w i t h i n t h e s a mp le . The same sample was i n v e s t i g a t e d w i t h a commerci al x - r a y CT s c a n n e r . F o r t h e same d e n s i t y r e s o l u t i o n ( ^ 0 . 5 % ) , t h e p r o t o n scan d e l i v e r e d a b o u t 5 t i m e s l e s s dose t o t h e sampl e t h a n t h e x - r a y s c a n . An e x p e r i m e n t now b e i n g p l a n n e d w i l l d e t e r m i n e w h e t h e r i n a d d i t i o n t o t h i s dose a d v a n t a g e , p r o t o n s p os s e ss a s i g n i f i c a n t a d v a n t a g e i n i m p r o v i n g c o n t r a s t . Muonic X- R a. y A n a l y s i s ( u X R ) T h e c a s c a d e x - r a y s p e c t r a p r o d u c e d when n e g a t i v e muons a r e c a p t u r e d i n a s am p le h av e been shown t o p r o v i d e i n f o r m a t i o n on t h e e l e m e n t a l c o m p o s i t i o n o f t h e sample and a l s o t h e c h e m i c a l e n v i r o n m e n t i n t h e c a p t u r e r e g i o n . Recent e f f o r t has been d i r e c t e d t o w a r d e l u c i d a t i n g c h e m i c a l e f f e c t s and a p p l y i n g t h e t e c h n i q u e t o s e l o c t e d p r a c t i c a l a n a l y t i c a l p r o b l e m s . R a d i a t i o n Damage S e v e r a l e T e c t r i e a 1 c o m p o n e n t s , i n c l u d i n g c a b l e s and c o n n e c t o r s , have r e c e i v e d n e u t r o n I r r a d i a t i o n s a t t h e beam s t o p r a d i a t i o n e f f e c t s f a c i l i t y ( R E F ) as p a r t o f a p r o g r a m t o i n v e s t i g a t e damage e f f e c t s on c r i t i c a l components used a t L A M P F . C e r a m i c vacuum t u b e s e c t i o n s we r e e x po se d t o 100 MeV p r o t o n p u l s e s a t t h e r e q u e s t o f R u t h e r f o r d L a b o r a t o r y t o d e t e r m i n e c r a c k i n g and s h a t t e r i n g t h r e s h o l d s . M a j o r c o l l a b o r a t o r s : J . R e i d y ( U n i v e r s i t y o f M i s s i s s i p p i ) , A . C o u l t e r ( U n i v e r s i t y o f A l a b a m a ) , M. R i c k e y ( I n d i a n a U n i v e r s i t y ) , H. Knowles ( W a s h i n g t o n S t a t e U n i v e r s i t y ) , M. K l i g e r m a n e t a l . ( U n i v e r s i t y o f New M e x i c o ) , A . D e n i s o n ( U n i v e r s i t y o f W y o m i n g ) , W. Cooke (Memphis S t a t e U n i v e r s i t y ) , W. K o s s l e r ( C o l l e g e o f W i l l i a m and M a r y ) , W. G a u s t e r ( S a n d l a L a b o r a t o r i e s ) , T . B l e w e t t ( A r g o n n e N a t i o n a l L a b o r a t o r y ) * A . F i o r y ( B e l l L a b o r a t o r i e s ) . -26 - "Medium E n e r g y N e u t r o n P h y s i c s R e s ea rc h and Mu on lc X - r a y S t u d i e s o f N u c l e a r S t r u c t u r e " 0 . E . Si mmons, B . E . B o n n e r , E . B . S h e r a , H . D . W o h l f a h r t , and M. V . Hoehn N e u t r o n P h y s i c s D ie p r i m a r y s c f e n t i f 1e o b j e c t i v e 1s t h e e x p e r i m e n t a l s t u d y o f t h e r t u c l e o n - n u c l e o n ( N - N ) f o r c e w i t h emphasis on t h e i s o s p l n - z e r o i n t e r ­ a c t i o n as m a n i f e s t e d 1n n e u t r o n - p r o t o n s c a t t e r i n g . The e v e n t u a l r e ­ s u l t w i l l be a q u a n t i t a t i v e measure o f t h e s c a t t e r i n g a m p l i t u d e s a t e n e r g i e s t h a t a r e f e a s i b l e t o o b t a i n a t L A M P F . The e x p e r i m e n t a l p r o ­ gram i n c l u d e s I n e l a s t i c as w e l l as e l a s t i c I n t e r a c t i o n s and e x t e n d s t o n e u t r o n s c a t t e r i n g f r o m l i g h t n u c l e a r t a r g e t s . I n r e c e n t e x p e r i ­ ments t h e e n e r g y dependence o f s c a t t e r i n g phenomena has been p u r s u e d by a t i m e - o f - f l i g h t method wh ic h has added I m p o r t a n t new I n f o r m a t i o n on n - p and n - d s c a t t e r i n g . The c o m p l e x i t y o f t h e N - N f o r c e 1s such t h a t s p i n p o l a r i z a t i o n e x p e r i m e n t s a r e n e c e s s a r y f o r f u l l u n d e r ­ s t a n d i n g . A p o l a r i z e d t a r g e t system has been d e v e l o p e d t h a t w i l l e n a b l e measurements t o be made on t h e s c a t t e r i n g o f p o l a r i z e d n eu­ t r o n s f r o m p o l a r i z e d p r o t o n s . Such e x p e r i m e n t s have n o t y e t been p e r f o r m e d a t medium e n e r g y and a r e e x p e c t e d t o p r o v i d e i m p o r t a n t new i n f o r m a t i o n . R ec e n t I n v e s t i g a t i o n s have i n c l u d e d : np d i f f e r e n t i a l c r o s s s e c t i o n s a t 800 MeV; np and nd b a c k - a n g l e s c a t t e r i n g f r o m 200 t o 800 M e V; s t u d i e s o f np p i o n p r o d u c t i o n l e a d i n g t o a f i n a l - s t a t e d e u t e r o n ; np a n a l y z i n g power f r o m 400 t o 800 MeV. Muo n l c X - r a y S t u d i e s TR e e x p e r i m e n t a l program c e n t e r s around t h e use o f t h e I n t e n s e s t o p p e d muon beam o f LAMPF t o s t u d y a v a r i e t y o f s t a b l e n u c l e i , w i t h t h e g o a l o f o b t a i n i n g new i n f o r m a t i o n on n u c l e a r c h ar g e d i s t r i b u t i o n s . Emphasis 1s p l a c e d on t h e d e v e lo p me n t and e x p l o i t a t i o n o f n o v e l ways i n w h i c h muons can be used t o s t u d y n u c l e a r p r o p e r t i e s and upon s y s t e m a t i c s t u d i e s o f sequences o f n u c l e i known f r o m o t h e r w o rk t o e x h i b i t I n t e r e s t i n g v a r i a t i o n s o f n u c l e a r p a r a m e t e r s . P r e c i s e v a l u e s o f r a d i a l c h a r g e d i s t r i b u t i o n p a r a m e t e r a r e b e i n g d e t e r m i n e d f o r e s s e n t i a l l y a l l s t a b l e I s o t o p e s I n t h e l f 7/ 2 , 2 P i / 2 . 2 p 3/ 2 » and I f 5/ ĵ s h e l l s . The muonic x - r a y d a t a , when combined w i t h e l e c t r o n s c a t t e r i n g r e s u l t s , y i e l d a h i g h l y p r e c i s e and m o d e l - i n d e p e n d e n t d e s c r i p t i o n o f t h e c har ge d i s t r i b u t i o n s o f t h e s e n u c l e i . A second a r e a o f s t u d y c e n t e r s on t h e d e f or me d and t r a n s i t i o n - r e g i o n n u c l e i . H er e t h e h i g h I n t e n s i t y o f t h e LAMPF a c c e l e r a t o r i s e s p e c i a l l y s i g n i f i c a n t s i n c e t h e amount o f a v a i l a b l e t a r g e t m a t e r i a l 1 s o f t e n v e r y l i m i t e d . I n t h e t r a n s i t i o n n u c l e i , muonic x - r a y measurements can r e v e a l 1n d e t a i l how t h e c h a r g e d i s t r i b u t i o n changes 1n p r o g r e s s i n g f r o m s p h e r i c a l t o d e f or me d n u c l e i . F o r e x a m p l e , 1n o u r r e c e n t muonic s t u d y o f t h e Os i s o t o p e s we have been a b l e t o show t h a t t h e e l e c t r i c m u l t i p o l e moments o f t h e s e n u c l e i a r e n o t a c c u r a t e l y p r e d i c t e d b y t h e b e s t e x i s t i n g m i c r o ­ s c o p i c t h e o r y . M a j o r c o l l a b o r a t o r s : U n i v e r s i t y o f T e x a s , T e x a s A&M U n i v e r s i t y , Case W e s t e r n R e s e r v e U n i v e r s i t y , Pu rd u e U n i v e r s i t y , F l o r i d a S t a t e U n i v e r s i t y , U n i v e r s i t y o f M a i n z ( G e r m a n y ) , and U n i v e r s i t y o f F r i b o u r g ( S w i t z e r l a n d ) . LOS ALAMOS SC IEN T IF IC LABORATORY...................................................... $300,000 FTTvTsTori LOS ALAMOS SC IEN T IF IC LABORATORY CNC OivTsTon $390,000 " N u c l e a r C h e m i s t r y R e s e a r c h a t L A M P F " B . J . D r o p e s k y , J . D . K n i g h t , C . J . O r t h , and G . W . B u t l e r The n u c l e a r c h e m i s t r y r e s e a r c h p ro g r a m a t L A MP F i s n a t i o n a l i n scope and p r e s e n t l y c o n s i s t s o f 19 e x p e r i m e n t s . T h es e i n v o l v e t h e p a r ­ t i c i p a t i o n o f some 64 s c i e n t i s t s , t w o - t h i r d s o f whom a r e f r o m 17 d i f f e r e n t U . S . i n s t i t u t i o n s , w h i l e t h e r e m a i n i n g a r e l . A S L r e s e a r c h e r s . The i n t e r a c t i o n s o f b o t h f a s t and s t o p p e d p i o n s r e s u l t i n g i n p r o t o n and n e u t r o n k n o c k - o u t , s i n g l e and d o u b l e c h a r g e e x c h a n g e , s p a l l a t i o n , f r a g m e n t a t i o n , and f i s s i o n a r e u n d e r i n v e s t i g a t i o n . The e s t a b l i s h m e n t o f good p l o n - b e a m m o n i t o r c r o s s s e c t i o n s has e n a b l e r e a c t i o n p r o b ­ a b i l i t i e s t o be p u t on an a b s o l u t e b a s i s . F o r t u n a t e l y , a s o p h i s t i c a t e d m o d e l , t h e I SOBAR v e r s i o n o f t h e V EGAS I n t r a n u c l e a r c a s c a d e c o d e , has been a v a i l a b l e f o r t e s t i n g a g a i n s t o b s e r v e d p i o n - i n d u c e d phenomena. The v a r i e t y o f p i o n a c t i v a t i o n e x p e r i m e n t s can be e x p e c t e d t o i n c r e a s e s t i l l f u r t h e r as t h e beam i n t e n s i t i e s a p p r o a c h t h e i r m a xi ma. P l a n s a r e a l s o b e i n g made t o e x p l o r e s e v e r a l i n - b e a m c o u n t e r - t e l e s c o p e t e c h n i q u e s t o c o m p l e m e n t t h e a c t i v a t i o n s t u d i e s by e x a m i n i n g s e l e c t e d a s p e c t s o f p i o n i n t e r a c t i o n s . Me as ur eme n ts o f p ro mpt y - r a y s f o l l o w i n g f a s t p i o n I n t e r a c t i o n s a r e b e i n g made. The i n v e s t i g a t i o n o f t h e compl ex e x t r a - n u c l e a r phenomena ( c h e m i c a l e f f e c t s ) a s s o c i a t e d w i t h t h e s t o p p i n g o f n e g a t i v e muons i n m a t t e r i s b e i n g v i g o r o u s l y p ur s u e d i n o r d e r t o o b t a i n i n s i g h t s and d a t a l e a d i n g t o q u a n t i t a t i v e models i n terms o f known c h e m i c a l s t r u c t u r e and w i t h t h e hope o f d e v e l o p i n g t e c h n i q u e s t o o b t a i n new i n f o r m a t i o n on c h e m i c a l s y s t e m s . Meas ur ement o f t h e mean muon l i f e - t i m e i n i n t e r a c t i o n s w i t h a c t i n i d e e l e m e n t s has been e x t e n d e d f ro m l o o k i n g a t d e c a y e l e c t r o n s t o i n c l u d e o b s e r v i n g n e u t r o n e m i s s i o n and f i s s i o n - t ' r a g m e n t e m i s s i o n . A l s o , n e u t r o n and p r o t o n k n o c k - o u t r e a c t i o n s i n d u c e d b y t h e e l e c t r o m a g n e t i c i n t e r a c t i o n o f f a s t muoris Mave r e c e n t l y been i n v e s t i g a t e d . A d v a n t a g e 1s a l s o b e i n g t a k e n o f t h e p r o t o n beam t o s t u d y i n t e r m e d i a t e e n e r g y r e a c t i o n s w i t h c omp le x n u c l e i t o an e x t e n t n o t p o s s i b l e b e f o r e . A t t h e T h i n T a r g e t F a c i l i t y , on t h e main p r o t o n b eam, i m p o r t a n t u s e i s made o f b o t h t h e u n i q u e l y h i g h i n t e n s i t y and t h e m i c r o s t r u c t u r e o f t h e beam t o me a su re t h e y i e l d s <)f l i g h t f r a g m e n t s ( t o A -V 4 0 ) e m i t t e d f r o m u r a n i u m and some l o w e r Z / t a r g e t s t o i d e n t i f y n ew , p a r t i c l e - s t a b l e n u c l i d e s , a n d , h o p e f u l l y , t o measure d i r e c t l y some n u c l e a r m a s s e s . N u c l e a r s p e c t r o s c o p y , r a d i o c h e m i s t r y , and i s o t o p e s e p a r a t i o n e x p e r t i s e c o n t i n u e t o be b r o u g h t t o b e a r on s t u d i e s o f an i m p o r t a n t n e u t r o n - d e f i c i e n t r e g i o n o f t h e n u c l e a r mass s u r f a c e by c o n s t r u c t i o n o f t h e d e c a y schemes o f many r a d i o n u c l i d e s pro duced t h r o u g h p r o t o n - i n d u c e d s p a l l a t i o n . The i n t e n s e f l u x o f e n e r g e t i c n e u t r o n s f r o m t h e L A M P F beam s t o p i s b e i n g e x p l o i t e d t o p r o d u c e new n e u t r o n - r i c h , s h o r t - l i v e d n u c l i d e s f o r c h a r a c t e r i z a t i o n . M a j o r c o l l a b o r a t o r s : B r o o k h a v e n N a t i o n a l L a b o r a t o r y ( H u d i s , H a u s t e i n , Remsberg) P u r d u e U n i v e r s i t y ( P o r l l e ) P r i n c e t o n U n i v e r s i t y (Naumann) L a w r e n c e B e r k e l e y L a b o r a t o r y ( P o s k a n z e r ) I d a h o N a t i o n a l E n g i n e e r i n g L a b o r a t o r y ( R e i c h , H e a t h ) Iowa S t a t e U n i v e r s i t y ( H 1 1 1 ) U n i v e r s i t y o f R o c h e s t e r ( H u i z e n g a ) T e x a s A&M U n i v e r s i t y ( N a t o w i t z ) U n i v e r s i t y o f O k l a h o m a ( P e t r y ) " E x p e r i m e n t a l R e s e a r c h : E l e c t r o m a g n e t i c I n t e r a c t i o n s and N u c l e a r S t r u c t u r e P h y s i c s " P . Demos, J . H e i s e n b e r g , W. C. B a r b e r , A , B e r n s t e i n , W. B e r t o z z i , I . B l o m q v i s t , D. I ngham, S . K o w a l s k i , 0 . M a t t h e w s , F . N . R a d , W. S a p p , C. P . S a r g e n t , W. T u r c h i n e t z , C. W i l l i a m s o n MASSACHUSETTS INSTITUTE OF TECHNOLOGY................................................... $1,140,000 This report covers the experimental research program in medium energy nuclear structure physics at MIT. The major part of the program is carried out at the Bates Linear Accelerator and i n ­ volves the study of electromagnetically-induced phenomena in nuclei. Some work is carried out at other accelerator fa c i l i t ie s and includes programs in hadronic scattering and hadron-induced reactions. Of the research at Bates, some is carried out inde­ pendently by MIT p hy sic ists , and some in collaboration with scientists from other institutions . A large component of the research at Bates is carried out independently by users from other in s t it u t io n s . The experiments at Bates are concerned with the two broad categories of electron scattering and electro- and photo-induced reactions. The electron scattering program encompasses elastic scattering and inelastic scattering to discrete states , and deeply inelastic scattering in the quasi-elastic region, involving nucleon knock­ out and pion production. The photoreaction program thus far has involved mostly studies o f the (y,ir) and the (y»p) processes, although some (y ,XN) studies of multinucleon emission are underway using induced radioactivity as the reaction indicator and some exploratory measurements have been made in (y ,d ) and (y»tl spectra. The electron, as an electromagnetic probe, possesses the advantage of employing an interaction which is well understood compared to the strong interaction of the hadronic probes. Used in electron scattering experiments on n u cle i , it carries the additional f l e x ­ ib i l ity of allowing the transferred momentum to be varied independently of the transferred energy. Also , due to the weakness of the electromagnetic interaction , the process and its representa­ tion are re lat ively uncomplicated. The spatial structure of the nuclear one-body charge, current and magnetization densities responsible for the scattering may be determined from the measured elastic and inelastic cross-sections with good precision . Electron Scattering Research The high resolution (Ap/p - 10"**) and high electron beam currents (~ lOOya) available with the MIT energy-loss spectrometer at Bates have permitted the measurement of many new or previously unob­ servable states in nuclei . The recent inclusion of specialized magnets designed by the University of Massachusetts group for 180 scattering allows greatly increased sensitivity in the measurement of the magnetic and electric current properties of the nucleus, in p articular for the nuclear ground state , for which measurements of these e f fects are usually overpowered at low momentum transfer and at angles forward of 180° by scattering from the static charge of the nucleus. -31- MASSACHUSETTS INSTITUTE OF TECHNOLOGY The measurements of nuclear ground state magnetization densities include work on 9Be, 170 and 101Ta, by an MIT group; work on 27A1, 93Nb and 25Mg by a group from the University of Massachusetts; work on l l s In and 3*K by a group including personnel from MIT and IKO Amsterdam; and work on H i by a Mainz , Saskatoon, MIT group. The Be results agree well with previous measurements from Amster­ dam and Stanford (HEPL) t and serve to confirm the capability and excellent quality of the 180° magnet system. The 170 data , which span the momentum transfer range 0 .S < q « 2 ,8 fm" 1 show unexpected behaviour. The shape of the Ml form factor d if fe rs considerably from that expected for a single d5/2 neutron model; the M3 form factor is greatly suppressed; and the data reveal a surplus of cross-section at the higher momen­ tum transfers , where none of the magnetic multipolarities are predicted to contribute s ignificantly . The measurements on l70 are part of a broader program underway to understand better the unusual electric and magnetic properties of the oxygen isotopes. The work on 181Ta, similarly, is part of the MIT program of study on the rotational nuclei . Taken together with the 180 ° scattering measurements from even-even rotational nucle i , the scattering from tantalum at 180° is shown to be ent ire ­ ly magnetic at q > 1 fm . Presuming this to be due to the magnetization produced by the valence nucleon of 181Ta, the data are in rough agreement with a theoretical treatment using a de ­ formed density-dependent Hartree-Fock model, but disagree (factor > 10) with a calculation which assumes the valence nucleon to move in a spherical potential . There appears to be good sen­ s it iv it y in the measurements, which are being extended in this and similar n u cle i , to the details of the nuclear deformation* In further studies of magnetic scattering, transitions of high multipolarity have been observed in 2ltMg, 28S i , 58N i , 5l*Fe and 208Pb. In 2^Mg and 28Si these have been seen as single strong transitions to 6 states (University of Toronto and MIT measure­ ments) , in 58Ni and 5l*Fe to groups of 8 " states (University of Massachusetts and M I T ) , and to states clearly identified for the first time as 12” and 1 4 " states in 208Pb (University of New Hampshire, University of V ir g in ia , M IT ) . Except for the 208Pb nucleus, which shows its expected strong shell model behaviour, the measured strengths of the other states observed in the rest of the above nuclei disagree with shell model predictions , possibly because of fragmentation of the strengths among many weak states , which are not included in the available theory. Electron scattering measurements have been completed by an MIT group of the ground state rotational bands of the deformed even- even nuclei 1” °Nd, 1S6Gd, l66Er, 176Yb, 2 32Th and 2 38U. Comparisons of the cross*section data with density-dependent Hartree-Fock calculations show generally agreement for the 0 and 2 states . The 4 + state measurements are not as well pre­ dicted by this theory, and agreement with the 6+ state cross sections is poor. -32- Certain vibrational levels observed in this work have been found to be represented successfully by small amplitude surface oscillations about a deformed nuclear core. In particular , c a l ­ culations based on this model were in good agreement with the measured form factors of the three observed members of the Kn * O' octupole band in 2 3 8U. A Physical Review Letter describing this result has been published. A comparison of data from the above work ( 2 * states in I 50Nd) was made also with calculations based on the interacting boson approximation model (IBA) . These showed a discrepancy which has beon interpreted as due to an unknown 1“ state unresolved from one of the 2 + levels. A picture consistent with the data following this interpretation has been published (Phys. Rev. Letters) . Measurements made on the odd-even deformed nuclei 167Er, l75Lu and 181Ta have shown features similar to those of the even-even nuclei . The form factors of these nuclei , additionally, exhibit differences when compared with those of their even-even partners which seem to show the polarizing effects of the odd nucleon upon the nuclear core . Rotational bands are under study also in a,*Mg (University of Toronto and M IT ) , in l,0Ca (Northwestern University, University of Lowell and M IT ) , and in 19F (Catholic University, Chalk River Laboratory, M IT) . The ground state rotational band in 2 **Mg is o f particular interest , showing properties in the form factor of its 4 + member which require an intrinsic spin (K»0 and K* * 2 mixing) of the !lartree-Fock model. The focus of interest in **°Ca is the rota­ tional band built on the 3 .353 MeV 0 level , using detailed shell model calculations to examine its particle-hole structure. The measurements, which have been completed and published, show good agreement of the ground-state rotational band form factors with theory, (variation-after-proiection Hartree-Fock) for q < 1 .7 fm . In other work, extended experiments on 207Pb and 208Pb have resolved more than 100 levels in these nuclei (University of New Hampshire et a l ) . In 2 0 7Pb analysis has been made and published (Phys. Rev. Letters) of specific neutron-hole and neutron-particle transitions which display strong longitudinal form factors due to core polarization induced by the neutron in transition . It is hoped that the data may give information on the neutron-proton interaction . Some thirty levels observed in 2 08Pb have shown mainly longitudinal form factors. The weak states among these are of particular interest , clearly exhibiting a single particle- hole nature. Many other experiments are curr3ntly underway in the electron-scattering program. Examples are: the charge-density comparisons of l 60 , *70 , and l80 (Lawrence Livermor$ Laboratory and M IT ) ; the transverse form factor of the f irst 2 state in l2C (University of Massachusetts); the single particle and collective MASS AC HU SETTS INSTITUTE OF TECHNOLOGY -35 - Construction of that magnet has been undertaken by the RPI physicists of the collaboration . The instrument will prrnit ex­ periments over a broad range of pion energies, from the near threshold region to beyond the ( 3 , 3 ) resonance and will be used in the measurement of differential-cross sections, for the exam­ ination of d iscrete nuclear excitations and for quasi-free photopion production studies. M a j o r c o l l a b o r a t o r s : Amsterdam F r e e U n i v . ( N e t h e r l a n d s ) , B o s t o n U n i v . C a t h d l i c Uni v T , C h a l k R i v e * ' N a t i o n a l L a b o r a t o r y ( C a n a d a ) , F l o r i d a S t a t e U n i v . , G e o r g e Mason U n i v . , U n i v e r s i t y o f Gl a sg o w ( U n i t e d K i n g d o m ) , IKO ( N e t h e r l a n d s ) , U n i v . o f I l l i n o i s , L a w r e n c e L i v e r m o r e L a b o r a t o r y , L o u i s i a n a S t a t e U n i v . , L o w e l l S t a t e U n i v . , U n i v . o f M a i n z (W. G e r m a n y ) , U n i v . o f M a s s a c h u s e t t s , U n i v , o f M o n t r e a l ( C a n a d a ) , N a t i o n a l Bu re a u o f S t a n d a r d s , U n i v . o f New H a m p s h i r e , N o r t h w e s t e r n U n i v . , N a v a l R e s e a r c h L a b o r a t o r y , Oak R i d g e N a t i o n a l L a b o r a t o r y , R e n s s e l a e r P o l y t e c h n i c I n s t i t u t e , U n i v . of S a s k a t o o n ( C a n a d a ) , U n i v . o f T o r o n t o ( C a n a d a ) , V a n d e r b i l t U n i v . , U n i v . of V i r g i n i a , V i r g i n i a S t a t e U n i v . , C o l l e g e o f W i l l i a m and M a r y , U n i v . o f W i s c o n s i n , W o r c e s t e r P o l y t e c h n i c I n s t i t u t e , U n i v . o f Wyoming, and Y a l e U n i v . MASSACHUSETTS INSTITUTE OF TECHNOLOGY UNIVERSITY OF MINNESOTA...... ScHooT~oT W y sics and Astronomy $ 80,000 "Nuclear Structure Studios at Intermediate Energies Using Protons and Pions" N. Ilintz and D. Dehnhard Our efforts emphasize study of nuclear structure using medium energy proton and pion probes. Priority is currently being given to elastic 'and inelastic scattering with both unpolarized and polarized (proton) beams using the HRS and EPICS spectrometers. Computer programs are being adapt.d to analyze the data with optical model, KtfT, DW8A and coupled channels reaction theories, Current efforts include: 1) Analysis of inelastic proton data on four nickel Isotopes from LAMPF Exp *139 (completed), 2) Analysis of inelastic proton data on six s-d shell nuclei (19p to 32S) from LAMPF Exp #178 (completed Aug. ’78). 3) Analysis of inelastic proton data on singly closed shell nuclei (5 targets) to search for high spin "orbit flip" states from LAMPP Exp #347 (completed Aug. *78). 4) Participation in LAMPF Exps #311 and #355, elastic scattering of polarized protons to large momentum transfer. LAMPP Exp #183, Inelastic Proton Scattering from Heavy Deformed Nuclei (Sm"to U) to study high multipoles in nuclear shape and to compare neutron deformations with proton deformations (from electron scattering). LAMPF Exp #411, to measure spin-.flip probabilities in inelastic scattering"to"collective magnetic states. 7) Exp #232„ "Inelastic Pion Scattering by ^*Mg and ^Mg". This~T!i a stucFy of elastic and inelastic tt+ and it scattering to low lying rotational and vibrational states. LAMPF Exp #369, "Inelastic Pion Scattering by 170". Special emphasis will be placed on a comparison of the inelastic ir+ and it" cross sections for the first excited state of 17q (i/2+). Thus this experiment allows a study of a transition that involves mainly the promotion of a single neutron from the lds/2 to the 2si/2 shells and large differences are expected between inelastic tt4 and it cross sections. Major collaborators: H. A. Thiessen, G. W. Hoffman, C. L. Morris, LASL; G. S, Blanpiod, New Mexico State Univ.; J. Moss, Texas ASM; and C. Glasshauser, Rutgers(on exp #411.) - 3 7 - " T o t a l P i o n C r o s s S e c t i o n Me a s u r e me n ts ' 1 M. J . J a k o b s o n and R . H . J e p p e se n The o b j e c t i v e s o f LAMPF E x p t . #Z " T o t a l P i o n C r o s s S e c t i o n s " a r e : 1 ) a c c u r a t e (±1%) d e t e r m i n a t i o n o f » t o t a l c r o s s - s e c t i o n s i n t h e ( 3 , 3 ) r e g i o n and be l ow f o r a r e p r e s e n t a t i v e s ampl e o f n u c l i d e s ; 2) e x p l o r a t i o n o f t h e u s e f u l n e s s o f such d a t a f o r e x t r a c t i o n o f d i f f e r e n c e s i n RMS r a d i i f o r d i s t r i b u t i o n s o f n e u t r o n s bound i n n u c l e i ; and 3) e x ­ t r a c t i o n o f p i o n - n u c l e u s i n t e r a c t i o n i n f o r m a t i o n ( e . g . t e s t o f t h e v a r i o u s v e r s i o n s o f o p t i c a l p o t e n t i a l s ) . T o t a l p i o n c r os s s e c t i o n wo r k i s t o be c o n t i n u e d , The t o t a l c r o s s s e c t i o n d i f f e r e n c e s f o r p a i r s o f i s o t o p e s o f a number o f e l e m e n t s have been measured and t h e s i g n i f i c a n c e o f t h e r e s u l t s i s b e i n g e v a l u a t e d ( 6L i , 7 L i ; 10B , n 8 ; 3?C , 1 3 C ; i 8 0 , 180 ; t* ° C a , t4tfC a , t<8C a . ) A l s o , some e f f o r t i s t o be expended on t h e measurement o f e l a s t i c c r o s s s e c t i o n s f o r 208 pb e n e r g i e s n e a r t h e Coulomb b a r r i e r and on p i o n s t o p p i n g power 1 r* l i g h t and h e a v y e l e m e n t s f o r e n e r g i e s up t o 100 MeV. T h e C a lc i u m i s o t o p e d i f f e r e n c e s have been p u b l i s h e d , The P i o n C r o s s s e c t i o n measurements f o r a l i g n e d 165Ho a r e a l s o p u b l i s h e d . T a r g e t s and e n e r g i e s t o be p u b ­ l i s h e d f o r tri i n c l u d e ^He 2 3 - 9 0 Me V; * 2C , ! 3 C 2 3 - 2 4 0 MeV. ® L 1 , 7 L i * Be « B 1 * 8 , 4 3 * 2 1 6 MeV; * « 0 , 1 8 0 , * * ° C a , ‘♦“ C a , * *e Ca . 4 3 - 2 4 0 Me V; <45S c , s i y , 2 ?A 1 , CUj S n , P b , 6 0 - 2 1 5 MeV. M a j o r c o l l a b o r a t o r s : M, C o o p e r , D . C . H a g e r m a n , and R. R e d w i n e , MP D i v i s i o n , L o s Alamos S c i e n t i f i c L a b o r a t o r y ; 1 . H a l p e r n , U n i v e r s i t y o f W a s h i n g t o n ; G , B u r l e s o n , K . J o h n s o n , New M e x i c o S t a t e U n i v . , H . M e y e r , U n i v e r s i t y o f B a s e l ; R . M a r r s , I n d i a n a U n i v e r s i t y ; J . C a h i r c o , S t a n f o r d U n i v e r s i t y ; S . A . B e c k e r , B . A , W a t s o n , and R . R , F i s h e r , L o c k ­ heed P a l o A 1 t o R e s e a r c h C e n t e r ; and H . M a r s h a k , N a t i o n a l Bu re a u o f S t a n d a r d s UNIVERS IT Y OF MONTANA, , , , ......................................................................... ............................... $ 1 6 ,7 0 4 d e p a r tm e n t o O h y s l c s a n d A s tro n o m y " N u c l e a r S t r u c t u r e S t u d i e s w i t h Medium E n e r g y P r o b e s " K. K . S e t h T he p r i m a r y t h r u s t o f r e s e a r c h un de r t h i s c o n t r a c t 1 s t o use medium e n e r g y p r o b e s - p l o n s , p r o t o n s , and e l e c t r o n s t o s t u d y a s p e c t s o f n u c l e a r s t r u c t u r e whi ch a r e n o t a c c e s s i b l e t o h e a v i e r o r l o w e r e n e r g y p r o j e c t i l e s , A v e r y s t r o n g component o f o u r r e s e a r c h r e l a t e s t o t h e d e l i n e a t i o n o f t h e s e p a r a t e r o l e s o f n e u t r o n s and p r o t o n s 1n t h e s t r u c t u r e o f n u c l e i , b o t h 1n g ro un d s t a t e m a t t e r d i s t r i b u t i o n s and e x c i t e d s t a t e d e f o r m a t i o n s . T o ­ wards t h i s end we ha ve been h e a v i l y i n v o l v e d i n LAMPF HRS and E P I C S e x p e r l - m e n t s - - # 1 4 : "ir and ti“ E l a s t i c and I n e l a s t i c S c a t t e r i n g f r o m i e 0 " ; #9: "»r+ and it" E l a s t i c and I n e l a s t i c S c a t t e r i n g f r o m 1, 2C a " ; # 1 3 9 : " P r o t o n S c a t t e r i n g S u r v e y w i t h H R S " j and # 3 1 1 : " E l a s t i c S c a t t e r i n g S u r v e y U s i n g P o l a r i z e d P r o t o m " . I n c o n j u n c t i o n w i t h p r e c i s i o n i n f o r m a t i o n on p r o t o n d i s t r i b u t i o n s f ro m e l e c t r o n s c a t t e r i n g , t h e e l a s t i c s c a t t e r i n g r e s u l t s f r o m t h e above e x p e r i m e n t s , p a r t i c u l a r l y # 3 1 1 , have g i v e n p r e c i s i o n i n f o r m a t i o n on n e u t r o n d i s t r i b u t i o n s 1n t h e gro und s t a t e s o f n u c l e i f r o m 1 2 C t o 20 eP b , E x p e r i m e n t #14 h a s , i n a d d i t i o n , shown t h a t s e p a r a t e d e f o r m a t i o n s o f n e u t r o n and p r o t o n components o f e x c i t e d s t a t e s o f 180 can be o b t a i n e d by t h e c o m p a r a t i v e s t u d y o f n and n " I n e l a s t i c s c a t t e r i n g . S i m i l a r i n f o r m a t i o n on s t a t e s o f 4 2Ca i s e x p e c t e d f r o m t h e j u s t c o m p l e t e d e x p t , #9. We a r e v e r y d e e p l y c om m it t ed t o t h e s t u d y o f d o u b l e c h a r g e exchange ( O C X) r e a c t i o n s (ir+ , 0 and ( t t “ , t t + ) on n u c l e i . T h es e r e a c t i o n s have no a n a l o g u e s i n c l a s s i c a l n u c l e a r p h y s i c s and t h e y a r e e x p e c t e d t o l e a d t o u n i q u e I n f o r m a t i o n on c o r r e l a t i o n s 1n n u c l e i and on p i o n d y na mi c s I n t h e n u c l e a r medium. We have j u s t c om p l et e d LAMPF E x p t . #13 " S t u d y o f n I nduced D o u b l e Charge E x c h an g e R e a c t i o n s " . T h e p r e l i m i n a r y r e s u l t s l o o k e x t r e m e l y I n t e r e s t i n g and w i l l u n d o u b t e d l y c o n t r i b u t e s i g n i f i c a n t l y t o t h e t h e o r e t ­ i c a l u n d e r s t a n d i n g o f t h i s compl ex r e a c t i o n . We have a l s o s u c ce e de d , i n m e a s u r i n g t h e mass o f t h e v e r y " e x o t i c " n u c l e u s 1 8 C by t h e (n",ir ) r e a c t i o n on 180 . U s i n g t h e h i g h r e s o l u t i o n s p e c t r o m e t e r , H R S , we a r e s t u d y i n g p i o n p r o d u c t i o n r e a c t i o n s ( p , n ) and ( p , i r ) w i t h p o l a r i z e d and u n p o l a r i z e d beams. T h es e i n v o l v e : E x p t . #1 0 /2 33 combinded v e r s i o n o f " S e a r c h f o r (p ,tt) R e a c t i o n s w i t h HRS" and " S e a r c h f o r A - C o n f 1 g u r a t 1 o n s i n N u c l e i " ; E x p t , #395 " ( p , i r + ) R e a c t i o n on 160 and ‘♦°Ca"i and £ x p t . #405 " ( p , i r “ ) R e a c t i o n on 1 2 C and 13C " . O n l y a smal l p a r t o f # 1 0 / 2 3 3 , ( p , i r + ) r e a c t i o n on h yd r o g e n and d e u t e r i u m , has been done so f a r . Q u i t e s u r p r i s i n g l y , t h e a sy mmet ry f o r D ( p , t r + ) shows s t r o n g s t r u c t u r e w h i l e t h a t f o r H ( p , w ) 1s e s s e n t i a l l y f l a t . C u r r e n t work a l s o i n c l u d e s two o t h e r p i o n - n u c l e u s e x p e r i m e n t s a t LAMPF and B AT E S E x p t # 7 5 - 5 " E l e c t r o n S c a t t e r i n g S t u d i e s o f Low L y i n g S t a t e s o f * * ° C a , 72G e , 9 ° Z r , and 9*Mo" and B A T E S E x p t . # 7 8 - 7 " A C o m p r eh e ns i ve S t u d y o f *t0Ca by I n e l a s t i c E l e c t r o n S c a t t e r i n g " . M a j o r c o l l a b o r a t o r s : L os Alamos S c i e n t i f i c L a b o r a t o r y , U C L A , U n i v e r s i t y o f T e x a s a t . A u s t i n , New Me x ic o S t a t e U n i v e r s i t y . - 4 0 - NORTHWESTERN U N IV E R S IT Y .............................................................................................................. $ 8 5 ,0 0 0 D e p a r tm e n t o f P h y s ic s and A s tro n o m y -41 - " I n t e r a c t i o n s o f L o w - E n e r g y P i o n s w i t h N u c l e i " F , E , B e r t r a n d , E , E . G r o s s , and C . A . Ludemann T h e p r o g r a m c o n s i s t s o f t h r e e p a r t s : i ) I n v e s t i g a t i o n o f t h e p i o n - a b s o r p t i o n me c hanis m u s i n g t h e n + + d r e a c t i o n , 1 1 ) e l a s t i c s c a t t e r i n g o f * ' , v " f r o m c omp le x n u c l e i , 1 1 1 ) I n e l a s t i c s c a t t e r i n g o f n , n * f r o m n u c l e i . T he s e e x p e r i m e n t s a r e p e r f o r m e d u s i n g p i o n beams f r o m t h e l o w - e n e r g y p i o n chan ne l a t L A M P F . A b s o l u t e d i f f e r e n t i a l c r o s s s e c t i o n s ha ve been measured f o r t h e n + + d -*■ p + p r e a c t i o n a t p i o n e n e r g i e s o f 4 0 , 5 0 , and 60 MeV. T h e se d a t a h av e r e c e n t l y been p u b l i s h e d . The a n g u l a r d i s t r i b u t i o n s o f t h e e m i t t e d p r o t o n s a r e a d e q u a t e l y f i t t e d by t h e u s u a l f u n c t i o n a l f o r m C0. + C * c o s 2e w i t h t h e a d d i t i o n o f a smal l c o s ^ e t er m y i e l d i n g o n l y a s l i g h t i m p r o v e m e n t . T h e I n t e g r a t e d c r o s s s e c t i o n s , wh ic h a r e much more a c c u r a t e t h a n t h e o l d e r d a t a , I n d i c a t e t h e p o s s i b i l i t y o f s t r u c t u r e 1 n t h e p 1 o n - a b s o r p t 1 o n v s . pion-momentum c u r v e . D u r i n g CY 1 9 7 9 we w i l l t a k e a d d i t i o n a l measurements a t l o w e r it'1' e n e r g i e s t o i n v e s t i g a t e t h i s p o s s i b l e s t r u c t u r e . E l a s t i c s c a t t e r i n g d i f f e r e n t i a l c r o s s s e c t i o n s have been o b t a i n e d a t t h r o e ir+ e n e r g i e s { 5 0 , 4 0 , and 30 MeV) f r o m f i v e t a r g e t s ( 12C , 160 , ^ C a , ■* °2r , and 206 P b ) . T h e c r o s s s e c t i o n s we r e d e t e r m i n e d w i t h an a b s o l u t e u n c e r t a i n t y o f ±7% o r l e s s . Meas urement s were made u s i n g an a r r a y o f t e n p l a s t i c s c i n t i l l a t o r d e t e c t o r t e l e s c o p e s . A l l o f t h e s e d a t a h a v e now been a n a l y z e d . C o m p ar i s o n o f t h e d a t a w i t h a f i r s t o r d e r o p t i c a l - m o d e l p o t e n t i a l y i e l d s good f i t s , p r o v i d e d t h e s t r e n g t h p a r a m e t e r s o f t h e K i s s l l n g e r p o t e n t i a l a r e a l l o w e d t o v a r y f r o m t h e f r e e Tt+ - n u c l e u s v a l u e . P r e l i m i n a r y a n a l y s i s shows t h e p o s s i b l e e x i s t e n c e o f an A - d e p e n d e n c e i n t h e r e a l p a r t o f t h e s t r e n g t h p a r a m e t e r s . T h e v a l u e o f t h e i m a g i n a r y p a r t s o f t h e p a r a m e t e r s shows l i t t l e change as a f u n c t i o n o f t a r g e t m a ss . D u r i n g CY 1 9 7 9 e l a s t i c s c a t t e r i n g m e a s u r e ­ ments w i l l be made on t h e same n u c l e i u s i n g 20-MeV v . I n a d d i t i o n , measure ment s u t i l i z i n g a m a g n e t i c s p e c t r o m e t e r w i l l be made o f b o t h tt and 7r“ e l a s t i c s c a t t e r i n g a n g u l a r d i s t r i b u t i o n s f o r p i o n s o f 60 t o 80 M e V , i n c i d e n t on s e v e r a l t a r g e t s . U s i n g t h e r e c e n t l y c o m p l e t e d " B i c e n t e n n i a l S p e c t r o m e t e r " , i n e l a s t i c s c a t t e r i n g m e as u re me n ts h av e been made on a f e w n u c l e i . Measurements o f t h e tr+ n u c l e a r c o n t i n u u m ( up t o % 25 MeV o f e x c i t a t i o n e n e r g y ) we r e made u s i n g 50-MeV tt on 160 , t* 0C a , 60 N 1 , and 208 P b . T he s e r e s u l t s h a ve been p u b l i s h e d . R e c e n t l y , I n e l a s t i c rr s c a t t e r i n g t o l o w - 1 y 1 n g 2 and 3“ s t a t r - s has been m e a s u r e d . These d a t a a r e c u r r e n t l y un d er a n a l y s i s . M a j o r c o l l a b o r a t o r s : L o s A la mo s S c i e n t i f i c l a b o r a t o r y , Ur, ' e r s l t y o f S o u t h C a r o l i n a , V i r g i . P o l y t e c h n i c I n s t i t u t e and S t a t e U n i v i i t y . OAK RIDGE NATIONAL LABORATORY............................................................. $ 75,000 U N I V E R S I T Y O F P E N N S Y L V A N I A , P h y s i c s D e p a r t m e n t -42 - 29,300 " R e s e a r c h I n V e r y H i g h Fnc o j , , a r P h y s i c s " S. Fr anke l and W. F r a t f The o b j e c t o f t h i s r e s e a r c h 1s t o o b t a i n e x p e r i m e n t a l I n f o r m a t i o n , t o c a r r y o u t p h e n o m e n o l o g i c a l i n v e s t i g a t i o n s o f t h e n a t u r e o f v e r y h i g h momentum components o f t h e n u c l e a r wave f u n c t i o n , t o d e v e l o p methods f o r e x t r a c t i n g such i n f o r m a t i o n f r o m I n c l u s i v e c r o ss s e c t i o n s , arid t o s t u d y mechanisms f o r h i g h e n e r g y n u c l e a r c o l l i s i o n s . The most r e c e n t l y c o mp l e te d e x p e r i m e n t s a r e : L AMPF 346 " St udy o f H i g h Moment um Components i n Nuc l e i U s i n g a Po l a r i zed F r o t o r T T e aifr T F f T ' e x p e r i m e n t was' W e f T r s t measurement o f a n d T y ~ f f n g"powe’r i n t h e r e a c t i o n p + A - + ( p , d , t ) + X f o r d e t e c t e d p a r t i c l e s 1n k i n e m a t i c r e g i o n s wh ic h r e q u i r e h i g h I n t e r n a l n u c l e o n momenta, We o b s e r v e d l a r g e n e g a t i v e a n a l y z i n g powers a t low momenta 1n L i 6 w h ic h became v e r y l a r g e and p o s i t i v e as t h e e n e r g y o f t h e d e t e c t e d p r o t o n i n c r e a s e d . S t r o n g A d e p endent e f f e c t s were o b s e r v e d . T h i s e x p e r i m e n t a l s o measured t h e f i r s t a n a l y z i n g powers f o r q u a s i - f r e e s c a t t e r i n g . F E RM I L A B 592 " P r o p os a l f o r E x p e r i m e n t a l S t u d y o f t he R e l a t i o n s h i p B e t ween Had ronTc" an'* N u d e a r S c a l i n g a t V e r y H i g h “E n e r g i e s 11 R c o m p ' l e t T L 5 GeV s p e c t T o m e t e r was b u i l t and I n s t a l l e d a t Fermi l a b t o s t u d y t h e r e a c t i o n p + A + ( p , d , t , H e 3 , H e 4 ,Tr » T r" , K , K " ) + X u s i n g 400 GeV p r o t o n s . The e x p e r i m e n t i s p r e s e n t l y b e i n g a n a l y z e d . The aims o f t h i s e x p e r i m e n t a r e t o use t h e s e i n c l u s i v e r e a c t i o n s and t h e known i n c l u s i v e r e a c t i o n s on f r e e p r o t o n t a r g e t s t o e x t r a c t n u c l e a r s t r u c t u r e f u n c t i o n s f o r n u c l e i f r o m L i t o P b . T he s e w i l l be compared w i t h t h e s t r u c t u r e f u n c t i o n s o b t a i n e d a t 0 . 8 G e V . E x p e r i m e n t s p l a n n ed f o r t h e n e a r f u t u r e i n c l u d e : LAMPF 258 T h i s e x p e r i m e n t w i l l measure t h e i n v a r i a n t mass d i s t r i b u t i o n o f t h e f i n a l s t a t e p r o d uc e d i n t h e r e a c t i o n p + A + p + X by m e a s u r i n g c o i n c i d e n c e s between t h e " b a c k w a r d l y " p ro duced p r o t o n s 1n a low r e s o l u t i o n s p e c t r o m e t e r ( u n d e r c o n s t r u c t i o n ) a . , ' t h e f o r w a r d p a r t i c l e s i n t h e e x i s t i n g Hi gh R e s o l u t i o n S p e c t r o m e t e r . F E RM I L A B " D e t e r m i n a t i o n o f t h e N a t u r e o f N u c l e a r J e t s " We are p r o p o s i n g t o s t u d y t h e f o r w a r d n u c l e a r j e t s 1n c o i n c i d e n c e w i t h t h e backward p r o t o n s o b s e r v e d 1n F E R M I L A B 59 2 . T he p u r po s e 1s t o d e t e r m i n e t h e mechanisms w i t h i n t h e n u c l e u s t h a t p r o v i d e t h e l a r g e n u c l e a r r e c o i l momenta demanded by o u r F e r m l l a b d a t a . FERMI L A S , S L A C , SACLAY We are now p l a n n i n g t o s t a r t t o use l e p t o n pro bes f o r " T h e s t u d y ~ o f n u c l e a r s t r u c t u r e f u n c t i o n s . M a j o r c o l l a b o r a t o r s : G. L e k s i n : A . V , A r e f i e v , Y . D . B a y u k o v , V , I . E f r e m e n k o , N . A . N i k i f o r o v , V . T c h l s t l l i n , and Y . M, Z a j t z e v , I n s t i t u t e o f T h e o r e t i c a l and E x p e r i m e n t a l P h y s i c s , Moscow. * U, B. COVEIlNMENT PllfNTlNO OFFICE : 1916 SOI-128/7JS -45- " S t u d y o f Muonlc A to ms " R . M, S t e f f e n We p l a n c o n t i n u a t i o n o f o u r s y s t e m a t i c I n v e s t i g a t i o n , b y p r e c i s e m u on lc x - r a y s o e c t . r o s c o p y , o f t h e c h ar g e r a d i i o f n u c l e i 1n t h e mass r e g i o n f ro m A ■ 40 t o A ■ 1 30 and o f t h e n u c l e a r s t r u c t u r e e f f e c t s 1n t h e t r a n s i t i o n r e g i o n s wher e n u c l e i change t h e i r s h a p e s , 1 , e , , t h e Sm- Gd and t h e H f - W - O s - P t r e g i o n s . I n p a r t i c u l a r , t h e c h a r g e r a d i i o f a l l s t a b l e P d , C d , and T e I s o t o p e s a r e p r o p o s e d t o be d e t e r m i n e d w i t h an a c c u r a c y o f + 1 0’ 18 m o r b e t t e r . I n a d d i t i o n , t h e q u a d r u p o l e moments o f t h e g r o un d s t a t e s o f t h e odd - A I s o t o p e s o f Pd and In w i l l be a c c u r a t e l y d e t e r m i n e d . The muo n lc atoms o f H f , W and P t w i l l be s t u d i e d w i t h h i g h p r e c i s i o n 1n o r d e r t o e x t r a c t t h e n u c l e a r c har ge m u l t i p o l e moments o f t h e e x c i t e d s t a t e s 1n a m o d e l - I n d e p e n d e n t w a y . T h e p r o b l e m o f t h e n u c l e a r p o l a r i z a t i o n c o r r e c t i o n w i l l be s t u d i e d 1n g r e a t d e t a i l b y e x p e r i m e n t a l and t h e o r e t i c a l mea ns , T h e f e a s i b i l i t y s t u d y o f u s i n g f i n e l y d i s p e r s e d t a r g e t m a t e r i a l 1n l i q u i d H2 1n o r d e r t o enhance t h e p r o b a b i l i t y o f p r o ­ d u c i n g muonlc atoms 1n t h e t a r g e t m a t e r i a l w i l l be c o n t i n u e d . The e f f e c t i v e c har ge r a d 1 1 o f 34 s t a b l e I s o t o p e s 1n t h e mass r e g i o n f ro m A ■ 40 t o A » 70 h av e been d e t e r m i n e d w i t h a c c u r a c i e s o f + 1 0 ' 18 m o r b e t t e r . S u r p r i s i n g l y I n t e r e s t i n g s y s t e m a t i c t r e n d s o f t h e I s o t o p e and I s o t o n e s h i f t s have been d i s c o v e r e d . The I so me r s h i f t o f t h e 2 . 6 1 MeV 3” s t a t e 1 n 20 ePb has been me a su re d. The o u a d r u p o l e c har ge d i s t r i b u t i o n moments o f t h e e x c i t e d s t a t e o f 1 8 6 * 1 8 f l * 190 * 1920s have been d e t e r m i n e d and f o u n d t o d i s a g r e e w i t h t h e r e s u l t s p r e d i c t e d by t h e p a i r i n g - p l u s - q u a d r u p o l e f o r c e model o f Kumar and B a r a n g e r . C u r r e n t l y o u r r e s e a r c h e m p h a s i z e s : 1 ) p r e c i s e d e t e r m i n a t i o n o f t h e e q u i v a l e n t c h a r g e r a d 1 1 and o f t h e I s o t o p e s h i f t s 1n t h e Cd and Te I s o t o p e s ; 2 ) measurement o f t h e n u c l e a r monopole and q u a d r u p o l e moments 1n * 50Sm, 152 Sm, 1860 s , 1900 s , 1920s and t h e Gd n u c l e i ; 3 ) d e t e r m i n a t i o n o f t h e n u c l e a r m a t t e r d i s t r i b u t i o n 1n t h e e v e n - A Cd n u c l e i b y p l o n i c X - r a y m e a su r e m en t s; and 4 ) s t u d y o f t h e t r a n s f e r o f muons s t o p p e d 1n l i q u i d h y dr og en t o h e av y a t o m s . M a j o r c o l l a b o r a t o r s : E . B . Sher a and H . D. W o h l f a h r t , L A S L PURDUE UNI VERSITY............................................................................. $ 50,000 Phys 1 cs C^paTrtmerlt * RICE UNIVERSITY............................... $303,533 P h y s ic s T5epartrnent "Intermediate Energy Nuclear Physics Studies" G. C. Phillips and G. S. Mutchler "4 6 ” This program emphasizes basic studies of nuclear structure and reaction mechanisms at intermediate energies* It espec­ ially concentrates on experiments leading to an understand­ ing of the N-N force and the roles played by inelastic channels such as N-a / A-A/ etc. Current work concentrates on the study of pion production amplitudes from nucleon- nucleon collisions in kinematically-complete two-arm ex­ periments. The study of these amplitudes began with LAMPF Experiment E-81, "Study of Neutron-Proton and Proton-Proton Coincidence Spectra from pd and pp Reactions," which clearly demonstrated the dominance of the reaction pp*A++n in pion production at 800 MeV. These studies are continuing in LAMPF Experiment E-336, "Study of the Spin Dependence of Proton-Proton Pion Production Reactions" through the spin dependence of the reaction pp*A++m in LAMPF Experiment E-366, "Non-resonant pion Production in the Reaction np*Mr~pp"; and, in future experiments, through the reactions np+nptr0 and pp̂ ppTr0* Work on LAMPF Experiment E-80, "Forward Elastic Scattering of and ir~ from 1*C, *3c, 4°Ca, 208pjyi has been brought to the final stages of analysis. Small angle elastic cross-sections covering the nuclear- Coulomb interference region and total cross-sections were measured for l«C, Ca, and 4®Ca at incident pion energies spanning the (3,3) resonance. These results provide funda­ mental information on both real and imaginary parts of pion- nucleus scattering amplitudes in the (3,3) resonance region. Data taking has been completed for LAMPF Experiment E-82, "Investigation of Pion Induced Reactions on Light Elements with Three Particles in the Final State,” SFtEL Experiment IC-54 0, "An Investigation of the Total Inelastic Pion Scat­ tering Spectrum for Energies Across the (3,3) Resonance;" and LAMPF Experiment E-341, "Study of pd+dtr+n Reaction Mechanisms." The SREL work resulted in pion inelastic scat­ tering data through 80 MeV excitation energy in the 12c tar­ get nuclei. Objectives included examination of the giant resonance region by means of pion scattering and extraction of total absorption cross-sections. Data analysis is now in progress. Experiments E-82 and E-341 are investigating quan­ titatively the dominant role of the A+{' in medium energy pion production and scattering reactions, fundamental amplitudes for understanding pion-nucleus scattering, and the ability of Glauber theory to describe both elastic and inelastic data. Major collaborators University of Houston UNIVERSITY OF ROCHESTER bepar tment of them i s try $24,000 "Muon-Induced Reactions on Actinide Nuclei" J.R. Huizenga Investigation of heavy muonic atoms is of considerable interest from several points of view: (i) Recently developed theories on muon capture predict a strong rate dependence on the neutron excess. Examination of capture rates for actin~ ide nuclei provides a test of these theories for very neutron~ rich nuclei, (ii) Since the energies of muonic transitions between the low-lying atomic states are larger than the neutron-binding energies and the fission barriers, radiation- less muonic cascade transitions may result in neutron emis­ sion or fission in the presence of the bound muon. (iii) The presence of the muon itself leads to a perturbation of the double-humped fission barrier owing to the muon-nuclear Cou­ lomb interaction. The present LAMPF study aims at under­ standing the several above processes occurring after a muon is stopped in the target. To date, capture rates have been reported for 232Th, 2 ^ ljU # 2 3 8 u and 2 3 9Pu by detecting elec­ trons from the normal .leptonic decay of the bound muon and for 232Th, 2 35U, 2 38U, 2^ 7Np, 2 3 9Pu and 21*2Pu by detecting neutrons. Analysis of the capture rates for 23^Th, 2 35u , 2 38u, 2 37Np, 2 Pu and 2t,2Pu by counting of fission frag­ ments is in progress. In the future we plan to study the nuclear Auger process in heavy muonic atoms. Major Collaborators W. K . H e n s l e y - L os Alamos S c i e n t i f i c L a b o r a t o r y D. W. P e r r y - L o s Alamos S c i e n t i f i c L a b o r a t o r y 0 . C . Browne - L awrence L i v e r m o r e L a b o r a t o r y -50 - " S t u d y o f t h e N e u t r o n - P r o t o n I n t e r a c t i o n 1n t h e 3 0 0 - 7 0 0 MeV E n e r g y R e g i o n " I . C . N o r t h c l l f f e , J . C . H l e b e r t , G . G l a s s , and T . S . B h a t l a T he o b j e c t i v e s o f t h i s w o r k a r e : t o d e t e r m i n e t h e s p e c t r u m o f n e u t r o n s p ro duc ed 1n 5 0 0 - 8 0 0 MeV p r o t o n bombardment o f d e u t e r i u m and o t h e r l i g h t e l e m e n t s ; t o use t h e mos t s u i t a b l e r e a c t i o n f o r t h e d e v e l o p m e n t o f m o n o e n e r g e t l c n e u t r o n beams needed t o s t u d y t h e n e u t r o n - p r o t o n i n t e r a c t i o n 1n t h e 5 0 0 - 8 0 0 MeV e n e r g y r e g i o n ; t o measure t h e d i f f e r e n t i a l c r o s s s e c t i o n s f o r e l a s t i c n e u t r o n - p r o t o n s c a t t e r i n g and f o r p i o n p r o d u c t i o n 1n n e u t r o n - p r o t o n c o l l i s i o n s a t 5 0 0 - 8 0 0 MeV; t o measure t h e n e u t r o n - p r o t o n p o l a r i z a t i o n and s p 1 n - c o r r e l a t 1 o n p a r a m e t e r s a t 500- 800 MeV. T h es e measure ment s w i l l c o n s t i t u t e a c o m p l e t e d e t e r m i n a t i o n o f t h e n e u t r o n - p r o t o n I n t e r a c t i o n 1n t h a t e n e r g y r e g i o n , r e a l i z i n g one o f t h e f u n d a me n t al g o a l s o f i n t e r ­ m e d i a t e e n e r g y p h y s i c s . T he 5 00 - 80 0 MeV n e u t r o n beams w i l l a l s o be used t o s t u d y t h e s p e c t r a o f c h a r g e d p a r t i c l e s p ro d uc e d i n n e u t r o n bombardment o f v a r i o u s n u c l e i . The e x p e r i m e n t s w i l l be c a r r i e d o u t a t t h e L os Alamos Meson P h y s i c s F a c i l i t y u s i n g a m a g n e t i c s p e c t r o m e t e r , m u l t i w i r e p r o p o r t i o n a l c o u n t e r s , s c i n t i l l a t i o n c o u n t e r s , a p o l a r i z e d h y dr o ge n t a r g e t , and o t h e r a p p r o p r i a t e i n s t r u m e n t a t i o n . R ec en t r e s u l t s i n c l u d e : D i f f e r e n t i a l c r o s s s e c t i o n f o r np e l a s t i c s c a t t e r i n g and a n g u l a r d i s t r i b u t i o n f o r np ►dn0 a t 4 6 3 , 6 4 7 and 800 Me V; c r o s s s e c t i o n s f o r np c h a r g e - e x c h a n g e and nD b a c k - a n g l e e l a s t i c s c a t t e r i n g 2 0 0 - 8 0 0 MeV; c r o s s s e c t i o n s f o r np n p r o - d u c t l c n a t 800 MeV; n e u t r o n s p e c t r a f ro m 6 4 7 and 800 MeV p r o t o n bombardment o f * H , 2H and v a r i o u s s o l i d t a r g e t s ; p and d s p e c t r a f r o m 800 HeV n e u t r o n bombardment o f v a r i o u s t a r g e t s . M a j o r c o l l a b o r a t o r s : J , E , Simmons and B , E , B o n n e r , L os Alamos S c i e n t i f i c L a b o r a t o r y P . J . R i l e y and C. L , H o l l a s , U n i v e r s i t y o f T e x a s M. W, M c N a u g h t o n , Case W e s t e r n R e s e r v e U n i v e r s i t y TEXAS A&M U N IV E R S IT Y ...................................................................................................................... $ 1 2 5 ,0 0 0 Phys'1 cs G e p a r tm e n t -51- U N T V E R S I T Y O F T E X A S AT A U S T I N ...................................................................................................................... $ 3 5 , 3 9 5 P h y s 1 cs 6e p a r t m e n t "M&'dlum E n e r g y Measurements o f n » p P a r a m e t e r s " P . J . R H e y L o n s t e r m o b j e c t i v e 1s a c c u r a t e and c o m p l e t e measurement o f n e u t r o n - p r o t o n s c a t t e r i n g p a r a m e t e r s I n t h e medium e n e r g y r a n g e . R e s e a r c h 1n p r o g r e s s I n c l u d e s measurement o f p o l a r i z a t i o n p a r a m e t e r s , a n g u l a r d i f f e r e n t i a l c r o s s - s e c t i o n s , I n e l a s t i c ( p i o n p r o d u c t i o n ) s c a t t e r i n g , and c h ar g e exchange c r o s s - s e c t i o n s . P r i o r i t y 1s c u r r e n t l y g i v e n t o d e t e r m i n a t i o n o f n e u t r o n - p r o t o n p o l a r i z a t i o n p a ra m et e rs u s i n g t h e P D i v i s i o n p o l a r i z e d p r o t o n t a r g e t . S p e c i f i c e x p e r i m e n t s a t v a r i o u s s t a g e s o f e x e c u t i o n I n c l u d e : L A MPF E x p t . #262 " T e s t o f I s o s p i n I n v a r i a n c e i n t h e R e a c t i o n n p* -dn°" L A MP F E x p t . 0263 " Me asur ement o f t h e E n e r g y and A n g u l a r V a r i a t i o n o f t h e np Char ge E x c h a n g e C ro s s S e c t i o n " L AMPF E x p t . #264 "Measurement o f t h e E n e r g y V a r i a t i o n o f t h e nD E l a s t i c D i f f e r e n t i a l C r o s s S e c t i o n n e a r 180 " L AMPF E x p t . § 65 " N e u t r o n - P r o t o n P o l a r i z a t i o n Meas urement s U s i n g a P o l a r i z e d T a r g e t : Phase I . The n - p P o l a r i z a t i o n O b s e r v a b l e P ( ©) " L AMPF E x p t . if 66 " N e u t r o n - P r o t o n P o l a r i z a t i o n Meas urement s w i t h a P o l a r i z e d T a r g e t : Phase I I . The N - P S p i n C o r r e l a t i o n O b s e r v a b l e , CNN <0 ) « LAMPF E x p t . #360 " T h e Measurement o f t h e P o l a r i z a t i o n T r a n s f e r C o e f f i c i e n t s D+ and A ' a t 800 MeV f o r t h e R e a c t i o n d ( p , n ) 2 p , 6 L 1 ( p , n ) B e , Snd V f p , " ) 5 S " M a j o r c o l l a b o r a t o r s : L os Alamos S c i e n t i f i c L a b o r a t o r y ( G r o u p P - 7 : B . E . Bo nner and J . E , Simmons) T e x a s A&M U n i v e r s i t y ( L . C , N o r t h c l i f f e ) " H i g h R e s o l u t i o n P 1 o n - N u c l e a r S c a t t e r i n g Measurements and 800 MeV P r o t o n Induced N u c l e a r R e a c t i o n s " C . F . Moore* W. J . B r a 1 t h w a 1 t e » and G . W. H o f f ma nn O u r I n t e r m e d i a t e e n e r g y e x p e r i m e n t a l n u c l e a r p h y s i c s p ro gr am e mp ha s iz es r e s e a r c h w i t h t h e H i g h R e s o l u t i o n S p e c t r o m e t e r ( HRS) and t h e E n e r g e t i c P i o n Channel and S p e c t r o m e t e r ( E P I C S ) a t t h e U s Alamos C l i n t o n P . A n d er s o n Meson P h y s i c s F a c i l i t y ( L A M P F ) . E x p e r i m e n t s a r e g e n e r a l l y co n ce r ne d w i t h i n e l a s t i c s c a t t e r i n g o f 800 MeV p r o t o n s and 5 0 - 3 0 0 MeV p i o n s f r o m complex n u c l e i t o examine s p e c i f i c f i n a l s t a t e s i n t h e s e n u c l e i . The o b j e c t i v e o f t h i s work i s t o b e t t e r u n d e r s t a n d n u c l e a r s t r u c t u r e and n u c l e a r i n t e r a c t i o n s w i t h I n t e r m e d i a t e e n e r g y p r o t o n s and p i o n s . R e c e n t e f f o r t s have I n c l u d e d LAMPF ( H R S ) E x p t . # 3 1 1 " E l a s t i c S c a t t e r i n g S u r v e y U s i n g P o l a r i z e d P r o t o n s , " and LAMPF ( E P I C S ) E x p t . 4$30 " E P I C S Tuneup P r o p o s a l : P i o n Carbon S c a t t e r i n g . " R e s u l t s o f LAMPF * ( E P I C S c h a n n e l ) E x p t . #265 " S t u d y o f Prompt N u c l e a r D e e x d t a t i o n Gamms| Rays f r o m P1 on I n t e r a c t i o n s w i t h 6 » 7L1 and 12C" have been p u b l i s h e d . E x p t . 0 3 1 1 d a t a 0 2 » l 3C . ' ♦ M 2 » ‘* t* , t»8Caj ' * M 8 . 5 0 T 1 , 5 6 , 6 ^ 1 , 90Z r , U M ^ s n , 5l4F e , and 20» P b a n g u l a r d i f f e r e n t i a l c r o s s - s e c t i o n and a n a l y z i n g power d a t a a t 800 MeV o v e r t h e 3 ° t o 23° ( l a b ) r a n g e ) a r e b e i ng v e r y s u c c e s s f u l l y a n a l y z e d i n terms o f t h e K e r m a n - M c M a n u s - T h a U r f o r m a l i s m . From #31 1 d a t a , e x t r a c t i o n o f r e l i a b l e , q u a n t i t a t i v e n e u t r o n d e n s i t y d i s t r i b u t i o n and s p l n - o r b l t p o t e n t i a l i n f o r m a t i o n a p p e a r s p r o m i s i n g . As p a r t o f LAMPF ( H RS ) E x p t . #355 " F u r t h e r E l a s t i c S c a t t e r i n g Cro s s S e c t i o n and A n a l y z i n g Power Measurements on 2O0Pb and 1 1 6 * 12l‘ S n , " t h e s e I n v e s t i g a t i o n s a r e b ei ng e x t e n d e d t o 3 5 ° . A c e n t r a l o b j e c t i v e o f #355 1s t o u n d e r s t a n d t h e s ou rc es o f KMT s h o r t c o m i n g s i n r e p r o d u c i n g a n a l y z i n g power d a t a a t l arg t- ( g r e a t e r t h a n 1 5 ° l a b ) a n g l e s . We a l s o p l a n work on LAMPF ( HRS ) E x p t . #347 " S e a r c h f o r ' O r b i t F l i p ' S t a t e s by I n e l a s t i c P r o t o n S c a t t e r i n g " and LAMPF (HRS) E x p t . #354 " S c a t t e r i n g o f 800 MeV P r o ­ t o n s From 12C -an d 1 3 C a t Momentum T r a n s f e r s G r e a t e r t han F o u r F e r m 1 s ‘ l . " E P I C S t u ne u p work ( # 1 3 0 ) on 1 2 C showed s t r o n g p e a k i n g a t 1 9 . 2 MeV e x c i t a t i o n f o r 164 MeV i n o f t i e n t p i o n s . T h i s p e a k i n g 1s n o t I m m e d i a t e l y u n d e r s t a n d a b l e i n terms o f .Mown 1 2 C s t a t e s . To e x p l o r e t h i s p e a ki n g 1n more q u a n t i t a ­ t i v e d e t a i l , we p l a n d a t a t a k i n g on LAMPF ( E P I C S E x p t . #368 " I n e l a s t i c P1 on S c a t t e r i n g To t h e 1 9 . 2 ± 0 . 3 MeV s t a t e I n 12C " . A l s o , t h e #130 r e s u l t s f o r it i n e ' f a s j i c s c a t t e r i n g f r o m 180 w i l l be p ur su ed w i t h LAMPF ( E P I C S ) E x p t . #229 "it v s . rr" I n e l a s t i c E x c i t a t i o n o f L o w - l y i n g C o l l e c t i v e S t a t e s i n N“ 28 N u c l e i . ir~ T h e c e n t r a l o b j e c t i v e o f #229 i s t o e x p l o r e t h e s e l e c t i v i t y o f v * ( i t " ) i n e l a s t i c s c a t t e r i n g f o r e x c i t a t i o n o f s t a t e s whose s t r u c t u r e o r d e f o r m a t i o n g r e a t l y d i f f e r s f ro m t h e g ro u n d s t a t e . M a j o r c o l l a b o r a t o r s ; H . A . T h 1 e s i ; e n , C h r i s t o p h e r L . M o r r i s , and James Amann - L A S L G e orge Bu r lt f co n and G a r y B l a n p l e d - New M e x i c o S t a t e U n i v e r s i t y J e r r y P e t e $ , o n and D i c k B o u d r i e - U n i v e r s i t y o f C o l o r a d o '* * # < n t z - U n i v e r s i t y o f M i n n e s o t a Ge or ge I g o - U n i v e r s i t y o f C a l i f o r n i a a t L os A n g e l e s - 5 2 - UNIVERSITY OF TEXAS AT A U S T IN ................................................................................................ $ 7 0 ,0 0 0 P h y s k s D e p a r tm e n t ~ “ U N IV E R S ITY OF V IR G IN IA $ 1 5 5 ,0 0 0 " E x p e r i m e n t s on t h e N u c l e a r I n t e r a c t i o n s o f P i o n s " R . C. M l n e h a r t a nd K . 0 . H . Z i o c k We a r e s t u d y i n g p i o n I n t e r a c t i o n s w i t h n u c l e i p r i m a r i l y u s i n g t he f a c i l i t i e s o f L o s A lamo s Meson P h y s i c s F a c i l i t y . The p u r p o s e o f t h e s e e x p e r i m e n t s I s t o e l u c i d a t e t h e b e h a v i o r o f p i o n s i n n u c l e a r m a t t e r and t o o b t a i n new I n f o r m a t i o n on n u c l e a r s t r u c t u r e . P r oc e s s e s s t u d i e d w i l l i n c l u d e e l a s t i c s c a t t e r i n g f ro m d e u t e r i u m , h e l i u m I s o t o p e s and c a l ­ ci um i s o t o p e s . We s h a l l a l s o s t u d y p i o n a b s o r p t i o n r e a c t i o n s and k n o c k - o u t p r o c e s s e s 1n l i g h t n u c l e i , T h e s e i n c l u d e (rr, n p ) , ( r r , t t A) , ( n , A ) , (ti+ , p ) r e a c t i o n s . We a l s o w i l l measure t h e ( n “ , ttc)inass d i f f e r e n c e t o new p r e c i s i o n . R e c en t r e s u l t s h a ve I n c l u d e d : p u b l i s h e d 7td e l a s t i c s c a t t e r i n g a t f o u r e n e r g i e s ; p u b l i s h e d r e s u l t s on ( it , Tip) i n t e r a c t i o n s 1n n u c l e i , measured Trd 2p a t 7 e n e r g i e s w i t h h i g h p r e c i s i o n ; measured e l a s t i c and c h ar g e e x c h an ge s c a t t e r i n g f o r p i ons 1n ^He and 3mj p u b l i s h e d r e s u l t s on s t u d i e s o f c l u s t e r e f f e c t s i n n u c l e a r p i o n c a p t u r e , I n c l u s i v e c r o s s s e c t i o n s f o r p a r t i c l e p r o d u c t i o n i n p , d , a c o l l i s i o n s w i t h n u c l e i ; measured r e a c t i o n s i nd u c e d by e n e r g e t i c a l p h a p a r t i c l e s ; measured ( n ‘ , N ) and ( t T . t j o ) i n ^ H e / ^ H e ; and measured n .■* e l a s t i c , q u a s l - f r e e and d o u b l e c har ge e x ch an ge s c a t t e r i n g i n c a l c i u m i s o t o p e s . M a j o r c o l l a b o r a t o r s : L A M P F , U C L A , U n i v . o f T e x a s , New M e x i c o S t a t e U n i v e r s i t y -56 - "Interactions of Pions with Nuclei" I. Halpern and J. G. Cramer Our main interests in intermediate energy physics center on the pion and the contributions it can make to our understanding of nuclear structure and reaction mechanisms by virtue of its unique properties (e.g., its low mass among the hadronic probes, its availability with both charge signs, etc,.,). A run on total inelastic scattering of positive pions to continuum energies was completed in June. It confirmed the "giant resonance’1 structures we saw last year in nickel and it showed oven stronger ones in magnesium and calcium. The spectra for heavier targets (e.g., Zr, Sn, Pb) were smoother than those for the light ones and showed no strong resonances above 10 MeV. In general, observed resonances are more conspicuous in the forward than in the backward hemisphere. The resonances in calcium were much less apparent at an incident energy of 85 MeV than at 67 MeV, We are in the process of trying to understand the nature of these resonances and of the integrated Inelastic scattering cross-sections. Older work still being pursued includes the analysis of data comparing total pion cross-sections on isotopes and the explanation of excitation curves for production from 12C and 12C by positive and negative pions. Prof. Cramer has a continuing interest in relativistic effects of the Coulomb interaction, particularly as they apply to the scattering of pions and other spin-zero projectiles from high Z target nuclei. Theo­ retical investigations of such effects in the coming year may lead to experimental investigations later on. Stimulated by interesting tandem results we have gotten on inelast-ic proton analyzing powers in the continuum, we have begun to explore the opportunities for similar investigations at the higher energies available at TRIUMF. UNIVERSITY OF WASHINGTON.. ..................................... $ 90,000 Major collaborators; Carnegie Mellon University of Wisconsin LASLUniversity of Alberta - 5 7 - " P 1 o n - N u c 1 e o n I n t e r a c t i o n s And Me so n lc A to ms " G , A . R e b k a , J r . and R. Kunselman A s e r i e s o f e x p e r i m e n t s has been I n i t i a t e d a t I A M P F t o s t u d y s e v e r a l c h a r g e s t a t e s o f t h e r e a c t i o n n e a r t h e i r t h r e s ­ h o l d s and t o compare t h e a v e r a g e m od ul i o f t h e m a t r i x e l e me n t s e x t r a p o l a t e d t o t h r e s h o l d w i t h t he p r e d i c t i o n s o f s o f t p i o n t h e o r y . T n es e e x p e r i m e n t s w i l l t e s t t h e a p p l i c a b i l i t y o f t h e t h e o r y t o t h e r e a c t i o n s and w i l l a l s o p r o v i d e more I n f o r m a t i o n a b o u t t h e p r o c e s s e s j u s t a bo ve t h r e s h o l d t h a n has p r e v i o u s l y been a v a i l a b l e . We ha ve measured d^cr/dftdT f o r t h e r r mesons 1n t h e c e n t e r o f momentum f o r TT“ p^ir"ir+ n a t s i x e n e r g i e s between 229 and 356 MeV w i t h a d o u b l y f o c u s i n g m a g n e t i c s p e c t r o m e t e r * and t h e s e d o u b l y d i f f e r e n t i a l c r o s s s e c t i o n s have been I n t e g r a t e d t o f i n d t h e r e a c t i o n c r o s s s e c t i o n , An a d d i t i o n a l e x p e r i m e n t now 1n p r o g r e s s w i l l meas ure t h e c r o s s s e c t i o n s f o r t h i s r e a c t i o n a t 200 a n d ’ 229 MeV t o r e d u c e t h e u n c e r t a i n t y 1n t h e p r o c e s s o f e x t r a p o l a t i o n . T h es e e x p e r i m e n t s a r e e x p e c t e d t o y i e l d t h e most a c c u r a t e measurements a v a i l a b l e f o r t h e S w a v e , I s o s c a l a r and I s o t e n s o r tttt s c a t t e r i n g l e n g t h s . ' I n a second s e r i e s o f e x p e r i ­ ments w i t h t h e same a p p a r a t u s , t h e c r o s s s e c t i o n f o r - n i - d o u b l e c h a r g e exc han ge 1n t h e d i s i n t e g r a t i o n o f u 0» “ ° C a , M8Ca and 200Pb w i l l be measured t o s t u d y t h e d o u b l e s c a t t e r i n g t e r m 1n n u c l e i . A t h i r d s e r i e s o f e x p e r i m e n t s w i l l s e a rc h f o r p r o ­ t o n s e m i t t e d i n u" c a p t u r e by n u c l e i . I n e x p e r i m e n t s a t t h e B a t e s A c c e l e r a t o r , t h e n u c l e a r s t r u c t u r e o f * 02W and 18I ,W w i l l be s t u d i e d t h r o u g h i n e l a s t i c e l e c t r o n s c a t t e r i n g , We a r e u s i n g muonic x - r a y measurements t o d e t e r m i n e n u c l e a r e l e c t r i c c har ge d i s t r i b u t i o n p a r a m et e r s and a r e u s i n g h a d r o n l c ( p i o n s , k a o n s , and a n t i p r o t o n s ) x - r a y measurements t o measure s t r o n g I n t e r a c t i o n e n e r g y s h i f t s and w i d t h s and t o d e t e r m i n e 1 s o t o p 1 c changes 1n n e u t r o n r a d 1 1 . C u r r e n t work I n c l u d e s : 1 . ) muonic x - r a y e x p e r i m e n t s on def ormed n u c l e i i n t h e t r a n s ­ i t i o n r e g i o n ; 2 . ) p i o n l c x - r a y e x p e r i m e n t s w i t h t h e Cal Tech b e n t c r y s t a l s £ e c t r o m e t e r t o t e s t t h e p i o n as a K l e i n G or do n p a r t i c l e ; 3 . ) pp x - r a y e x p e r i m e n t s a t t h e AGS t o d e t e r m i n e s t r o n g I n t e r a c t i o n s h i f t and w i d t h p a r a m e t e r s i n t h e I s s t a t e ; and 4 . ) p i o n i c x - r a y e x p e r i m e n t s on med1um-Z n u c l e i . M a j o r c o l l a b o r a t o r s : l o s Al amo s S c i e n t i f i c L a b o r a t o r y W i l l i a m and Mar y U n i v e r s i t y o f V i r g i n i a C a l i f o r n i a I n s t i t u t e o f T e c h n o l o g y Or eg on S t a t e U n i v e r s i t y M a s s a c h u s e t t s I n s t i t u t e o f T e c h n o l o g y U N IVERS1TV OF WYOMING...................................................................................................................... $ 1 2 5 ,0 0 0 P h y s ic s D e p a r tm e n t LOS ALAMOS SCIENTIFIC LABORATORY, MPDivision $18,760,000 "Fac ility Oporation, Development, Maintenance and User Support" L. E. Agnew, J. F, Anann, J. Bergstein, J, A, Bridge, A. A. 8rowman, R. D. Drown, E. D. Bush, H. S, Butler, R. L. Cady, E, P. Chamberlin, D.R.F. Cochran, K. R, Crandall, R, A. DeHaven, J. E. Donahue, P. R. Franke, A. J, Gjovlg, D. L. Grisham, D. C. Hagerman, R, A, Hamm, V. E. Hart, R, E. Harris, J. F. Harrison, R. E, H i l l , E, W. Hoffman, G, W. Hoffmann, R, A, Jameson, 0, J, Jarmer, R. Kandarian, S. P. Koczan, T. Kozlowski, J. D. L itt le , R. J. Macek, D. R. Machen, C. E. ‘langer, 0. R, McConnell, C. L. Morris, R. H. Newell, J. K, Novak, M, A. Oothoudt, D. G. Perry, T. M, Putnam, S. E. Rlslove, L. Rosen, 0. R. Sander, G. H. Sanders, E, J. Schneider, D. D, Slrrmonds, R. R. Stevens, Jr., G. R, Swain N. Tanaka, H, A. Thlessen, R. T. Tregellas, 0. B. van Dyck, J. D. Wallace, R. F Warner, R, D, Werbeck I. INTRODUCTION LAMPF Is unique 1n that i t combines the hiqhest current proton accel­ erator in the world with a very versatile experimental fa c i l ity so that many different fields of experimental research can be served simultaneously. The very high current requires great strength in applied physics, enainearing and technology 1n order to effectively operate and further develop the fac il ity . Similarly, the diverse nature of the exnorimental program requires exnert support 1n many different technical fields. The overall format of this report imolles that the operation of this fa c i l i ty is distinct and apart from the research program. This Impression is quite misleading since the success of the research program denends strongly on successful operation and development of the fa c i l ity . Conversely, success­ ful ooeratlon of the fa c i l ity would be oointless, even a contradiction, with­ out a successful research orogram. Section I I below gives an overall description of the scooe and status of the LAMPF fac il ity . Section I I I oives a more detailed scope-of-work state­ ments for many of the activities that are a part of the operation of LAHPF. I I . SCOPE AND STATUS OF THE FACILITY LAMPF 1s the major laboratory in the United States for experimental work in medium energy physics. The fa c i l ity represents the state-of-the-art 1n nearly a ll important aspects of its performance. At the time of writing an H+ current of 360 yA (nearly 300 kW of beam power) and a simultaneous H" current of a few microamperes are routinely available for the experimental program. As required, the H" beam can be polarized to provide a few nano- amperes of current., A maximum duty factor of 7*$ is available. Typically, 10 to 13 separate experimental teams make use of the fa c i l ity at the same time. Production beam 1s scheduled for these users some 4000 hours per year. Beam ava i lab i l ity 1s 1 n excess of 803$ which 1s very good considering the complexity of the fa c i l i ty . The extremely large proton currents used at LAMPF are d if f icu lt to produce and to use. Tuning of the accelerator 1s very demanding since, in addition to the high intensity requirement, the quality of the beam must be excellent. The amount of beam lost 1n the accelerator and beam switchyard must be limited to a very low level since a ll components in this part of the f a c i l i t y must be accessible for hands-on maintenance without significant radia­ tion exposure to maintenance oersonnel. In the target cells the proton beam -61- I I , SCOPE AND STATUS OF THE FACILITY (Continued) produces large amounts of undesirable radiation and sign ificant heat loads in addition to the desired meson beams. The resulting radioactive environment presents a d if f icu lt engineering problem 1n reoions accessible only by remote handling techniaues, Figure 1 1s a simplified plan view of the experimental area, This figure includes a tabulation of channel Intensities. The experimental program for the fa c i l ity is based on the recomtienda- tions of a Program Advisory Committee (PAC) who review proposals for experi­ ments submitted by the scientific conrnunity. After a particular experiment is recommended by the PAC and approved by the LAMPF Director* scheduling and experimental support is arranned throunh the LAMPF Scheduling Committee (LSC), Development of the fa c i l ity is directed through an Exoerimental Area Development Committee (LADC) and an Accelerator Development Committee (ADC); members of these committees come from the senior LASL s ta ff associated with LAHPF. A Technical Advlsiory Committee (TAP) provides a formal route for the LAMPF Users Organization to make recommendations for further development of LAI'tPF. Near-term development ooals for the fa c i l ity include hioher H+, H", and polarized beam Intensities, further increases in duty factor, more time*' sharing options so that use of the fac1Htv is made more flexible, and con­ tinued improvements of the permanent spectrometers and secondary beams. I I I . MAJOR ACTIVITIES 1. Facil i ty Operation In a fac i l ity as complex as LAMPF i t is essential that the operation be done by well-trained, professional operators. Their major responsibility 1s the safe operation of the fa c i l ity combined with maximum beam availab ility. In order to fu l f i l l this responsibility they tune the accelerator and primary beam lines, control access to many beam areas, act as lia ison for experimental support problems, do on-line maintenance, and generally oversee the LAMPF site (particularly outside normal working hours). In addition to actual operation and on-line maintenance of the machine, operations activ it ies include: performance of experiments and measurements required for further development of the accelerator, development and documenta­ tion of accelerator operating and on-line repair procedures, maintenance of operating records, periodic testing of interlocks, contingency assistance to experimenters, and training of operating personnel. An operations support prooram 1s closely allied with the actual opera­ tion of the machine and includes: maintenance and repair of local Instrumenta­ tion and control computer interfacing equipment distributed throughout the fa c i l ity , paging and interphone systems, closed-circuit television equipment, a distributed pulse-viewing system, and beam-intensity and loss-monitoring equipment. Interlock systems for personnel safety and machine protection are also maintained, improved, and extended to new experimental areas as needed. During FY 1978 the H+ beam intensity was increased to 360 yA and an average beam ava ilab ility of over 80% was achieved. The H“ beam intensity S lOuA PROTON BEAM HIGH RESOLUTION PROTON SPECTROMETER (HRS) SEAM STOP NEUTRONS external PROTON AM (E.5® BEAM AREA 8 LAMPF BEAMS M E X K t a u m u AKIAS BEAM AREA C ISOTOPE PRODUCTION ft radiation effects FORWARD NEUTRON SEAM PIPES S 10 f t A H'BEAM 8 0 0 McV J mA PROTON BEAM 8 0 0 M«V T T F c o p p e r BEAM STOP N m sTnznos PULSED PROTON BEAM TO WEAPONS NEUTRON RESEARCH AREA { WNR) BEAM A R EA A CHANNEL ENERGY {MeV) BEAM CHANNEL ENERGY {MeV} SEAM LOW ENERGY PJ0N 0 - 3 0 0 3 x l0 V /s OS 8 x108 t ~/s NEUTRONS (AREA B ) 795 I0*n/cm 2 -s HIGH ENERGY PION CP3) {00-600 4*\<?r+/s OR 6 s I0 8 t ' / j NEUTRONS (BEAM STOP) 1 - 2 0 I0,5n/cm2 - * EPICS WON BEAM 5 0 * 3 0 0 2 * S 0 * ir ^ OR 5 x» 7t '/i * NEUTRONS {BEAM PIPE) 1 -8 0 0 K pn /S tt? STOPPED MUON 0 - 1 6 5 10 V / l ° * 3 * K > V * BIOMEDICAL 0 - 1 0 0 10*1r“/» TEST CHANNEL 5 0 - 6 0 0 5 * t o V % OR 6 x ICST */ t NEUTRINOS 2 0 - 5 0 3 * 1 0 7 r /c » H * - CHANNEL INTENSITIES QUOTED AOOVE ARE FULL OPEN RATES AT ImA PftOTON CUftftENT AND THE H0UXWHN6 TMQET THCX*£S$£S A -1 3 c * CAMK3N «■ ^ . # D ' IASI. iUXMAMO««CtaMt»CU«C^ATOMY Fig. 1 A-2 |(M CMSON *-5 ScmCAIMOW -65- r>. Direct Support for Users (continued) Each approved LAMPF experiment is assigned an experiment engineer, who is placed in contact with the Research team well In advance of the scheduled beam run'. This engineer helps coordinate the timely preparation and setup of the experiments. The LAf'Pr Electronics Equipment Pool (LEEP) has an inventory of 2600 items representing an investment of S1.83M. Experimenters withdraw equipment from the pool when they begin to mount an experiment. This equipment has been reconditioned and tested before 1t 1s Issued and 1t is maintained during the course of the experiment after which i t Is returned to the pool. A committee of experimenters advises the LEEP personnel on new equipment to purchase or develop. During FY 1P78, a total of *5220” worth of new equipment was added to the LEliP pool. Most of this expenditure was for HIM and CAMAC modules, but some of it went for other equipment such as a disk pack cleaner and delay boxes. In addition, several devices recently introduced on the commercial market were ordered for evaluation. The LAMPF Experimental Maqnet Pool Includes about QO units, procured primarily from other fa c i l it ie s through excess property. When the magnets are removed from storane and placed in use for the f i r s t time, they are extensively refurbished and tested in preparation for Installation in the experimental area. The magnets are catalogued and described 1n the Pool Magnet List that 1s up­ dated and distributed to reflect new additions or more detailed operating parameters. A pool of maqnet stands, target and detector mounts, instrument arms, and remote-control mechanisms 1s now well established and continues to expand. A magnet measurement service capable of precision field mapping 1s provided, A model and oroduction shop has been set up to support the LAMPF experi­ mentalists' pnrtlcle-detector requirements. Sc intillation detectors, optical piping, light interfaces, and multiwire proportional counters (MWPCs) are currently being supplied to the user experimentalists. In addition, th is shop supplies the haros used along the accelerator and beam lines for beam- diagnostic purposes. A metrology fa c i l i t y 1s maintained to provide an optical calibration service, to lend optical instrumentation to the experimentalists for on-line use, and to provide support for the experiment engineers in preci­ sion aligning the experimental apparatus. Shop fa c i l i t ie s , a hot-cell fa c i l i ty , a tool crib, and supplies of commonly used stock items are provided in the main experimental hall. Techni­ cal assistance in the mounting of experiments Is made available, including crane and fo rk l i f t service, mechanical assembly and weldina, water systems, gas systems, liquid nitrogen supplies, and many other services as required. Through the establishment of a modest drawing account for each outside experiment, a means for scheduled experiments to make direct use of LASL f a c i l ­ it ie s, support organizations, and general stores for immediate and essential needs that arise during the preparation and performance of an experiment has been provided. III. MAJOR ACTIVITIES -66- III. MAJOR ACTIVITIES 6. Cryogenics Support . A pool of refrigeration equipment 1s provided for experiments using liquid hydrogen and other cryogenic tarqets. Tho high-power liquid deuterium system used for neutron production is maintained. Cryogenics engineering and technical assistance are provided as regulred to design, construct, In sta ll, and operate existing or new equipment, Twenty-two cryogenic target systems were built and operated for 14 experiments during FY 1978. Much of the hardware of the standard 10-W refrigeration systems was replumbed and improved substantially. A simulator system for a microprocessor controller was designed and is belno constructed. Improved versions of other electronic control systems have been designed. Considerable effort was devoted to cryogenic engineering for future experi­ ments. A cryogenic shop/laboratory with suitable safety equipment was con­ structed. The HERA polarized proton target system, consisting of a 25-kG super­ conducting magnet and a polarized proton target cryostat, was received from CEN-Saclay, The magnet and polarized target cryostat were tested and inte­ grated with the various auxiliary support systems (3lle and Ĥe pumplnq systems, 3lle gas-handling system, microwave, and NMR systems). A system for recovery of the helium gas used in polarized target ooeration has been placed into service. 7. .Computer Support The computer systems grouo 1s charged with the development of a compre­ hensive computer-based data-acquisition and analysis system to support the pro­ gram of experimental nuclear nhvslcs. The activ it ies covered In this effort include (1) the purchase of computers and peripheral devices* {?.) the develop­ ment of general-purpose and specialized software, (3) the exploitation of the CAMAC standard for interfacing experimental apparatus to computers, (4) the development of a 24-h maintenance service for the equipment, (5) the manage­ ment and maintenance of an electronics equipment pool for LAMPF users, and (6) the development of a state-of-the-art electronics capability to support the system. A three-day study of the requirements for a data-analysls fa c i l i ty was held 1n FY 1977. A dozen specialists drawn from a ll sectors of the LAMPF user community met to review the present status of the data-analysis problem and attempted to forecast future needs. A number of recommendations were made 1n a report (LA-7034-MS) that was presented to the users at their annual meeting 1n November. Procurement actions were initiated for the acquisition of equip­ ment to respond to the recommendations of the study. An order was P l a c e d for a PDP-11/70 to upgrade the PDP-11/45 as the Terminal computer. The present POP-11/45 will b e "moved to P3-East to replace the PDP-11/34 that w i l l be used on the control computer. An order was nlaced for a computer to support the development of software for the data-acqu1s1t1on computers, The paperwork for the purchase of a VAX-11/780 was submitted. This is the f i r s t major step toward a fa c i l i ty to handle the data-analysis load at LAMPF. The general data- acquisition program Q was adopted by most of the experimental teams. This program was designed to provide users with all the software functions commonly used to acquire, preprocess, display, record, and analyze data. A large effort was concentrated on documentation of the program and the resulting manuals were 7. Computer Support (continued) dtstrlbuted .to the user. A.number.of Improvements.were made .1n Q as.the • result of user feedback and several major enhancements are in progress. 8. Targets The mesons and neutrons delivered to secondary beams 1n Areas A and B are produced by targets 1n the proton beams. Graphite targets are used at three locations in Area A for the pion and muon beams, and both liquid deute­ rium and beryllium targets are used to produce neutron beams in Area B, Especially d if f icu lt requirements are placed on the pion production targets because of LAMPF's Intense beams, These targets must operate at high temperatures 1n a vacuum, must survive intense radiation levels, and must be inserted remotely. At the f i r s t two target stations on the main beam line, rotating target wheels made of a standard type of graphite are used. Energy deposited in the target by the beam is distributed evenly around the circum­ ference of the wheel and is radiated away at temperatures up to 1500°C, Dur­ ing FY 1978, these target systems were rebuilt with new drive mechanisms and special high-temperature bearings for increased re liab ility , Pyrolytic graphite, which is denser and has more favorable strength and thermal conduction properties than standard graphite, is used for pi bn production at the third target station on the main beam line. This target serves the Biomedical P1on Channel. Extensive efforts have lead to the recent development of a technologically-advanced water cooling system for the bio­ medical target that is based on a high-performance graphite-to-metal bonding method. In Area B, high-quality neutron beams with a wfell-resolved high-energy spike 1n the forward direction are generated by 3- to 5-pA proton beams on a liquid deuterium target. A "white" spectrum of neutrons produced from rela­ tively thick beryllium tarqets is also aval 9• Primary and Secondary Beam Lines The primary beam lines deliver LAMPF's h1qh~1ntensit.y beams to three pion production targets, several irradiation stations, a hiqh-energy neutron fa c i l ity , and the beam stops 1n a safe and reliable fashion for routine multiple-use operation. In Line A, operation at very nigh Intensity requires extreme precision in beam tuning and the full utilization of advanced radiation- hardened diagnostic devices. Several-fold redundancy in protection against faulty beam control, magnet current faults, and vacuum and water systems failure 1s provided. The secondary beam lines 1n Area A (low- and high-energy pion channels and a stopped muon channel) and. in Area B (the external proton beam and the high-energy neutron beams) provide the Intense high-quality beams of pions, muons, protons, and neutrons for medium-encrgy physics‘and nuclear chemistry research at LAMPF. A test channel in Area A provides a moderate quality beam of charged particles for development and testing of experimental apparatus. These fa c i l it ie s cover a very broad range of exoerlmental requirements and simultaneously serve experiments at each channel. A number of Improvements in primary beam*l1ne components, diagnostics, monitoring Instrumentation, beam-11ne protection instrumentation, and’optical -67- III. MAJOR ACTIVITIES 14. Control,Computer- (continued) replacing tiie present computer with a new one having higher parformance, a more modern arghitecture, and better maintenance fa c i l it ie s . The general plan 1s to surround the present SEL-840 with Inte lligent I/O processors that can communicate with both the present and future control computers and then phase out the present computer. The pace of this project 1s slow because the SEL-840 must be on-Une to the accelerator throughout the year, and this commitment leaves only a limited amount of scheduled downtime in whiut to accomplish each step of the changeover* However, all main subsystems (the disk* RIU» console, and Master Timer) received attention during the past year. Work continued on the third operator's console that will be tota lly Interfaced through CAMAC. The develonment work on the CAMAC-based, general- purpose information bus (GPIB) controller and Its integration with the function- button panel was completed. A keyboard Interface to the GPIB was designed, bu ilt , and tested. A color character scope with a CAMAC Interface was pur­ chased, Installed, and tested. When the supporting system software 1s com­ pleted 1t will be possible to do a GPIB system analysis using the CAMAC/GPIB controller, function-button panel, keyboard, and color display. The knob/ readout panels and trackball are next on the l i s t of developments. The f ir s t generation of a new Master Timer was completed and Integrated Into the control system. The timer is organized around a microprocessor which, before every pulse, examines reouests for timing signals from up to 23 gate generator modules and produces the appropriate signals on the next pulse. The new unit can operate in various modes, I.e . , 1t can impose different constrain­ ing relations among the various timing signals. This feature will become increas­ ingly important as the complexity of accelerator operations grows in response to the demands of the experimental program. A major effort was invested in software to support all the new devices. The Master Timer, the new disk system, and the third console, Including the color display, required several levels of systems programs 1n more than one computer. These developments were Intermixed with diagnostic work to identify and correct computer faults. A rich variety of application programs was written 1n response to requests from the Operations staff. 01 splays and auto­ mated procedures dominated the 11st. The software maintenance activ it ies touched almost every program 1n the repertoire. The spectrum of modifications resulted from the discovery of errors, new modes of operations, slow responses, revisions of procedures, and changes 1n accelerator hardware. The extension of the accelerator control systems along the main beam lines, to provide for effective delivery of beam to the targets in the experi­ mental area and the development of instrumentation and controls for the second­ ary beam lines, 1s essential to the operation of the experimental fa c i l it ie s . The activ it ie s associated with this work Include: (1) the completion of the local computer controls for the primary and secondary beam lines, (2) the development of computer programs for operating and monitoring of the beam-line equipment, (3) the expansion of the sate llite computer network for beam diag­ nostic instrumentation, (4) the extension of the accelerator timing system into the experimental areas, (5) the development of a computer-based beam-11ns protection system, and (6) the maintenance of all the instrumentation and con­ tro ls in the experimental areas. -70- III, MAJOR ACTIVITIES 15. Beam Diagnostics Activ it ie s Beam diagnostic equipment provides the beam Information needed to tune th e 'fac il ity and to characterise different beams formed during development work. This equipment must be reliable, accurate, and suitable for the h1gh-1ntensity beams used at LAMPF. Thr act iv it ie s required are repair, preventive mainte­ nance, calibration, development of special check-out equipment and procedures and upgrading various devices. S k i l ls needed for this activity Include systems engineering, circuit and instrumentation design, electronics fabrication, vacuum and alignment support, mechanical design and fabrication, and materials technology expertise. During FY 1978 a nonintercepting {team Position Monitor system was in ­ stalled on the accelerator that permits accurate measurement of beam position at high intensity, emittance and wire scanner devices received study on l i f e ­ time and accuracy at; higher currents, and an accurate method of measuring beam-phase width at 121 MeV was developed. 16. Radio Frequency Power Systems The r f systems supply the power to accelerate the beam. These are divided into four categories: (2) 805-MHz hiah-power rf, (2) 201.25-MHz high- power r f , (3) low-level rf, and (4) phase and amplitude control. There are some 108 separate r f subsystems. All of these must operate simultaneously near peak performance to satisfy the requirements for acceptable beam. To achieve this level of performance with good ava ilab ility requires: (1) diag­ nosing and correcting weak points in system design, (2) training and main­ taining a highly skilled crew that can be available at any time to repair failures in a minimum amount of tine, (3) develooino preventive maintenance procedures and schedules to minimize machine failures durinp operational peri­ ods, (4) ensurinq that adequate spare parts are available in the event of fa ilures, and (5) taking advantage of any advances in the state-of-the-art that will Improve performance and re l iab i l ity of the systems. Upgrading the rf systems is accomplished through modification of spare units that are then cycled into the machine during maintenance periods, thus releasing more units for modification. Work was done on recabling, marking cables and components, and documenting the rf source room and the At system 1n order to improve performance and Increase maintainability. Effort was put into studies and minor changes to improve stab ility of the At system and accel­ erator tank resonance controllers. Problems that developed with the high-power r f transmission lines in the 201.25-MHz system and the closed-loop controllers on the buncher cavities due to the higher rf duty factors and higher peak beam intensities were resolved by design changes to the hardware. Changes to the machine fast-protect system to avoid theproblems of transients on the closed- loop controllers required redesign and Installation of new detection hardware on a ll of the r f systems. The 805-MHz solid-state IFA design was enlarged to include a strip-11ne fast phase shifter In the same package. Construction and installation of these new units was well under way by the end of FY 1978. Modifications to the r f system that resulted in significant energy savings were made. Capacitors were procured and Installed to Increase the size of the r f energy storage banks. This change Increases overall system efficiency, thus generating a new energy savings and also enables the systems to better handle the higher Intensity, high-duty beams being run in the machine. An effort was also made to attempt to standardize gain and set up of the r f system components 1n order to reduce the control margin needed for the equipment. -71“ III. MAJOR ACTIVITIES 16. Radio Frequency Power Systems (continued) This procedure, along with reductions in delay times used for building fields 1n the cavity, resulted in additional energy savings. 17. Injectors There are three injectors in use that provide simultaneous H+ and H“ beams with the option of either polarized or unpolarized H- beams. These injectors require a continuing maintenance effort. A number of development programs are 1n progress that are aimed at Improving the performance of existing systems, implementing new systems to provide greater f le x ib i l i ty in modulating injector beams, and 1n designing and testing new 1on sources to meet antic i­ pated requirements for brighter beams at higher intensities. During FY 1978, development on the H+ source was directed at optimizing the performance of the LAMPF duoplasmatron to produce high brightness and this has resulted 1n an Increase of injected beam brightness by a factor of three. The operation of the H~ Injectors continued with half of the H“ beam time being devoted to polarized and the other half to unpolarized beams. Polarized beam currents of a few nA on targets have been produced while unpolarized beams up to 6 pA have been supplied, Considerable effort was spent in improving the transverse emlttance of the unpolarized H“ beam to permit simultaneous operation with the higher Intensity H+ beams now required. A fast-sp1n-f11p capability has been Installed on the polarized ion Injector and 1s now being used to provide suitable polarized beams for experiments looking for parity violation, Develop­ ment of higher intensity polarized beams by optimizing accel-decel geometry 1s continuing. 18. Klystron and Vacuum Pump Rebuilding The l i f e of klystrons at LAMPF has been surprisingly long; one klystron has demonstrated 1n excess of 40,000 hours of operation. However, 1n view of the large number (44) of klystrons used and the fact that these tubes are manu­ factured specially for LAMPF, I t i s an operational and economic necessity to operate an 1n-house klystron rebuilding fa c i l ity . This fa c i l i ty 1s 1n routine operation rebuilding approximately one tube per month. As further experience Is gained 1n tube rebuilding, both tube design and the repair fa c i l i t y will be upgraded as required. In connection with this rebuilding a modest effort is made on Improved tube design. The swltchtubes used 1n the klystron modulators require reprocessing several times to maximize their total l i fe . This work is done in the klystron repair shop. Some 127,000 l ite rs per second of pumping capacity (176 ion pumps) are operational in the fa c i l ity . One hundred forty-three of these pumps are associated with the accelerator, with the remainder installed on the main and secondary beam lines. Operational experience indicates that these pumps have a normal l i fe expectancy of three years. An ion-pump rebuild fa c i l i t y pro­ vides replacements for the active units. Two large brazing furnaces are used routinely in the rebuilding program, on work in support of experiments, and for general fabrication. -72- III. MAJOR ACTIVITIES (HK 03 02) Includes a ll costs associated with experimental Nuclear Physics activ it i carried out at fa c i l i t ie s with primary beam particles more massive than helium-4, ’ HEAVY ION NUCLEAR PHYSICS ' HEAVY ION NUCLEAR PHYSICS - RESEARCH (HK 03 02 01) Includes a ll costs of heavy-iori nuclear research activities. Heavy-Ion Physics Research ................................ K, L. Wolf* B. B. Back, I. Ahmad, A. M. Friedman, 0. P. Unik This program is directed to obtaining a comprehensive understanding of the interactions which take place during co ll is ion between heavy nuclei ranging from intermediate to re la t iv is t ic energies. A collaborative effort with the Universities of Rochester and Maryland (RAM Group) continues at the LBL Super HILAC studying deep Inelastic processes with very heavy ions below 8.5 MeV/nucleon. Recent measurements have shown that the neutrons emitted from deep inelastic events are predominately due to evaporation processes from post-sdssion fragments. Studies of the 56pe + 20901 reaction have shown an apparent departure from the "universal" energy dissipation vs charge dispersion relation­ ship. Resonances have been observed 1n the energy spectrum of products resulting from the 56Fe + 56Fe reaction which may be indicative of an entirely new reaction mechanism. Another multllaboratory collaboration, led by ANL and including MSU, University of Maryland and LBL is conducting experiments at the LBL 88-inch cyclotron. Complex three body correlation experiments studying the >&0 + 23°U reaction at 20 MeV/nucleon are used to determine the linear momentum transfer for events with projectle-like reaction products (°Li to <»0). The results, to date, show that this mechanism 1s neither fragmentation nor deep in­ e lastic transfer, but a new process with an intermediate momentum transfer. Re lativ istic heavy-ion research, performed at the LBL Bevelac in collaboration with LBL staff, u tilizes i r crocs section measurements to provide Information on collective phenomena, Fermi motion, and tests of several co llis ion models. In the reaction 40a + 40ca ->■ tt+ + X at 1.05 GeV/nucleon, there is a strong indication of the nuclear fireball mechanism being operative. Several other interesting effects have also been observed which are interpreted 1n terms of nuclear shadowing and i r absorption 1n nuclear matter at high density and temperature. Experiments with high-prec1s1on beams from the ANL Superconducting Linac, when available, will emphasize gawna-ray and ligh t charged-particle multip lic ity measurements to provide a detailed understanding of the excitation energy balance and angular mr -ntum transfer 1n heavy-1 on reactions as well as the nature of high-sp ,i states in nuclei. ARGONNE NATIONAL LABORATORY ............................................................... $151*000 TFiefnfs'try bfvTsfon Superconducting Linac Development G. T. Garvey, P, R. Fields, L. f), Bollinger, K, w. Shepard, R, Benaroya, A, H. Jaffey, T. K, Khoe, P. Markovich, C, II, Scheibelhut, T, P, Wangler This program, carried out jo intly by the Chemistry and Physics Divisions, is concerned with investigations of the general aspects of applications of superconducting technology to the acceleration of heavy ions, Most of the recent ac t iv it ie s have been related to the development of an accelerating structure of the sp l it -r in g type made of niobium, Specific tasks, some of which are ongoing, include development of (1) a good rf joint, (2) a new superconducting materia1, consisting of niobium sheet that is explosively bonded to copper, (3) resonator-diagnostic techniques (4) a new kind of phase-control device, and (5) beam-dynamics computer programs, Since FY 1976, there has been a companion project (see "Heavy-Ion Energy Dooster") concerned with the specific task of adding a small superconduct ing linac as an energy booster for heavy ions from the FN tandem Van de Grasff accelerator, This booster project will be completed by the end of FY 1979, ARGONNE NATIONAL LABORATORY ................................................................... $415,000 PRyslcs T5Tvision/Chemistry Division During FY 1978, the effort in the Superconducting-Linac Development Program is focussed on the specific developmental needs of the heavy- ion energy booster. I t is planned that this approach will continue during the f i r s t part of FY 1979, but then, when the booster project has been completed, the nature of the developmental program will change substantially; the level of effort will be somewhat reduced, and the function of the group will be broadened to include: (1) a less focussed program of development of superconducting-1 inac tech­ nology, including investigations of basic technical problems that have necessarily been bypassed during the booster-construction phase, (2) the solution of problems of specific interest for the booster, (3) the transfer of the new rf technology to other in stitu t ions, and (4) the investigation of other technologies of interest to the nuclear science community. AftGOMl NA1JOHAI LABORATORY Heavy-Ion research at the Tandem and Superconducting Linac Accelerators The high-resolution study of Inelastic scattering has produced a set of data of unique quality. It Is proving to be an Interesting testing ground for the Indirect effects of strongly-coupled channels In direct reactions, and tends to confirm the qualitative picture that has been evolving from the study of the more macroscopic features of direct processes, The Investigation of high angular momentum states is one of the major frontiers in nuclear physics, An important advance 1n this field came in the discovery by a Danish-German-US(Argonne) co!laboratlon of high- spin 1somer1sm--a feature of nuclear structure that holds out consider­ able promise for the future and has great potential in connection with the pulsed beam of the superconducting Hnac f*n*»rav booster. An important activity during this period has been the design and partial implementation of an experimental beam line to carry out research with the heavy-ion beams from the superconducting energy booster to the tandem, The objective is to have a working experi­ mental system when the booster becomes available for research 1n late 1978, The in it ia l beam line 1s at 0% requiring no bendir*} magnet after the linac sections, It is designed to have carefu’ily controlled beam optics 1n order to allow focusing of the beam at any one of four potential beam stations along it, The vacuum system is designed to be free of organic contaminants, in order to reduce problems associated with carbon contamination, The beam stations will be occupied by a 65-inch scattering chamber, a single-arm chamber suitable for simultaneous charged-particle and neutron time-of-flight measurements, a gamma-ray multiplicity counter and a He-jet system for the study of delayed radiations. Tills set of experimental stations will allow for a strong in it ia l program in heavy-ion research on the superconducting linac. In the f ir s t experimental use of the Hnac (September 1978), an 160 beam was used to study the fragmentation of l,0Ca in a small temporary scattering chamber on the zero-degree beam line. The pulsed character of the beam was used to measure the velocity and hence the mass of reaction products, -81- Nuclear Reactions Induced by Energetic Heavy long J. 8, Cuoaing, P, E, Hausteln, J. Hudia, S, Katcoff aHOOKHAVP* HAT I OH AI, LABORATORY < ..................... , , , 5131,000 Cheftl8try~ Departoent A few years ago it becatse apparent that Che nuclear interactions of high-energy heavy ions were siailar in many ways to those of protons, Although studies of eaitted particles did reveal more copious (mission of more energetic light fragments for incident heavy ions, evidence for predicted new processes ouch as shock wave# or states of abnormal density has not »ateriali?,ed, The BNL research seeks a comprehensive understanding of the more usual types of reactions as well as evidence for novel processes through measurements of radioisotopes produced by irradiation of targets with heavy ions and by the use of nuclear track techniques, Data from similar experijaents with energetic protons and w masons are valuable for comparison with the heavy ion results within the framework of a theory originally developed to account for elementary particle interactions. This theory predicta the onset of asymptotic behavior in which target-fragmentation cross sections beconie energy Independent, and dependence on the bombarding particle is only via a total cross election term. Experimental cross section surveys of the interaction of various heavy ions with copper have shown broad mass regions where such predictions appear valid. Attention la now being focused on the measurement of more detailed properties — the mean kinetic energy of and the Momentum transferred to selected products, Significant differences in the latter quantity when reactions of 25-GeV ions are compared with those of 28-GeV protons are Interpreted as indicating deviations from limiting behavior at 2,1 GeV/nucleon. The dependence of such deviations on energy and projectile type Is being further explored^in experiments with lower energy £ons fln£j high- and low-energy He Ions. As techniques improve and heavy-ion beam intensities increase, direct measurements of product angular distributions and energy spectra are planned. These are of special Interest in light of the novel, sideward peaked angular distributions reported recently for reactions Induced by very high energy protons. Cross section surveys will be extended to Kr and Xe projectiles if these become available. BROOKHAVKN NATIONAL UBORATORVPhysica Department $1,292,000 Heavy-ion Physics with the Tandem Van de Graaff Facility N. P. Samioa, M. Blurae, A. W. Sunyar, A, Z, Schwarsachild, D. E. Alburger, C, Baktash, J. Barrette, P. D. Bond, C. Chasman, F. der Mateosian, D. Horn, 0. C, Kiatner, S. Ktibono, M. J. LeVine, C. K. Lister, J. W. Olness, E. K. Warburton, H. E. Wegner The baaic questions in heavy-ion nuclear phyaice are concerned with (a) the way in which large pieces of nuclear matter interact with one another in regions of energy, angular momentum, and even denaity not present for stable nuclei near their ground atatea, (b) how mat- ter, energy and angular momentum pass between such aggregates, and (c) the manner by which excess matter, energy and angular momentum is disposed of by the residues of heavy-ion induced reactions. The Tandem Van de Graaff Facility provides unique capabilities for studying these fundamental problems of nuclear physics. Continu­ ously adjustable high energies and a great variety of different heavy projectiles, combined with the excellent beam characteristics of Van de Graaff accelerators, offer new opportunities tor probing the prop­ erties of nuclear states in a totally new region of angular momentum ae well as Investigating the dynamics of such new nuclear reactions. The rich diversity of available heavy-ion beams makes it possible to carry out a multi-faceted heavy-ion experimental program at the Tande* Facility. This experimental program is carried out both by the resident staff and by an outside user community with approximately equal alloca­ tions of beam time. Crucial to the success of the entire experimental program is the availability of Important analytic tools such as the QDDD spectrometer with its large solid angJe, forward angle capability and superior focal-plane detector energy resolution, as well as data- collection and data-analysis capability of the on-line Tandem computer system. General areas of research which art currently being actively pursued include: studies of states of high angular momentum produced by heavy-ion compound nuclear reactions, studies of heavy-ion direct reaction mechanisms, production of "exotic" nuclei far from the line of ntability and spectroscopic studies of their level structures, and ex­ amination of heavy-ion induced fission and fusion processes. In addi­ tion, heavy-ion beams are used for investigations of atomic processes such as x-ray production by heavy ions and the energy-loss mechanisms of heavy ione In matter. The range of ion species and energies as well as the variety of major pieces of experimental equipment and data ac­ cumulation systems make possible many experiments that cannot be car­ ried out elsewhere. Heavy-ion reactions result in the excitation of a rich variety of nuclear states and afford unique methods to Investigate OF PB-Jf9 M * * L ± P £ ANGC.US ..................................... $ 60,000 Apartment o f Physics ~ Relativistie Heavy Ion Nuclear Reactions G. v. fgo, J. B, Carrol 1 At the Bevalac, re la t iv ist ic heavy ion probes, % 2 GeV/N l<0Ar and “ C have been used to measure the rapidity dependence of bght-ion, s i ngl e-part I c 1 e inclusive reactions on light nuclear targets,. The associated multiplicity distribution of high-energy, singly and doubly charged particles were measured. The principal conclusions of this experiment are: 1) the shape of the rapidity distributions are insensitive to the multiplicity, J?) no enhancements in the rapidity distributions were found which could be attributed to coherent (shock waves for instance} phenomenons; and 3) the single-particle inclusive spectra arc* in good agreement with the "firestreak" model. (The "fire* streak" model has been found to be capable of explaining single-particle inclusive data taken under a broad variety of experimental conditions, i.e. various beam energies, targets, projectiles, and in a large range of the rapidity region). CARHEGJf-MELLON UNJ VERS J T Y .................. .............................. 1103,500 Department of Chemistry Nuclear Research with Heavy Jons H, Kaplan The research program is directed towards experimental studies of nuclear reactions Induccd by heavy ions in complex nuclei. It Involves a collaboration between Carnegie-Melioii University and SUNY at Stony Brook and utilizes the SuperfULAC and 88" Cyclotron accelerator fa c i l it ie s of the Lawrence Berkeley Laboratory, Our emphasis is on the detection and measurement of light charged particles emitted in deeply inelastic collis ions using counter tele­ scopes to record both the singles events and the coincidences with heavy fragments. The identification of JH, 2H, 3M, and ''He particles is accomplished by means of three-element Si surface barrier detector telescopes, and energy spectra and angular distributions are obtained. Heavy fragments from the reactions are measured with gas-ionization chamger telescopes which provide atomic number identification and fragment energies, Correlations between light charged particles and heav.v fragments, and between two heavy-fragment partners, provide detailed insights into the dynamics of the reaction mechanism, The l igh t particles evaporated from fu lly accelerated fragments yield information on the excitation energies and spins of the equilibrated reaction products, whereas those particles which are emitted prior to thermal equilibration give us a view of the early stages of the reaction. Parallel studies of charged particle emission and fission in closely related compound nucleus reactions allow us to model the de-excitation properties of heavy nuclei at high energy and spin. These models can then serve as experimental calibrations and input for theoretical calculations which are needed for interpreting the more complex deeply inelastic processes observed in nuclear reactions of very heavy ions. V -87- § t O R G ! A J NSTJ TUTE O r K C H N O L O G V % 7 2 , 4 2 8 department of Chemistry' Nuclear and X-ray Spectroscopy with Radioactive Sources R, W, Fink, J. t. Wood This program H a systematic study of nuclei far from stab il ity with radioactive sources produced with heavy ions from the Oak Ridge Isochron­ ous Cyclotron and mass-separated on-Hne by the UNISOR fac ility . Such experiments complement in-beam reaction spectroscopy (which is confined to high-spin states) and are the only means of exploring the low-spin structure of nuclei far from stab ility . This research investigates; (1) core-particle coupling models and the role of the Fermi energy; ( 2 ) shapes of transitional nuclei; (3) pairing correlations in transitional nuclei; (4) shape and pairing isomerism; (5) shell model intruder states; and (6) proton-neutron correlations; as well as a search for new radio­ active nuclides. Currently the emphasis is on transitional regions bordering Z * 82 (Isotopes of Pt, Au, tig, T1, Bi, and Po), These studies are complemented on-campus by related work on x-rays from radioactive sources (fluorescence and Coster-Kronig yields for 1 * 64-83), lifetimes of certain nuclear excited states, computer codes for data analysis, and radioactive nuclides produced in the 5 MW Georgia Tech Research Reactor, ihmna b? w . u < immow Nuclear l>t ience D i v i s i o n W . O O O Coulomb \.m . 1 t i o n arid In-Beam Spectroscopy P. M. Diamond, T, fj. Stephens Our aim is to study and to understand some of the important aspects of run. r s t ructu re , and e sp e c ia l ) / the changes induced by high amiular momentum, We m e beams of very heavy Ions ('•0Ar through ;" ‘/‘f,b) from the SuperHlLAC and of sna i l or Ions ( ' ’He through ,,0A r) from the 88" cyclotron. We have exp lo ited the e s p e c i a l l y useful p ropert ie s of tieavy ions, namely, t he i r la rge nuclear charge, the ir large l inea r momentum lead ing to large re co i l v e l o c i t i e s of the st ruck target nuc le i , and the largo amounts of angula r momentum they may b r ing to a compound system, The high charge makes the heav iest ions those o f choice for Coulomb e xc i t a t ion s tud ie s of the h ighest spin s ta te s p o s s ib le , for Coulomb- induced f i s s i o n s tu d ie s , and for the t ran s ien t production of super­ c r i t i c a l nucle i during the c o l l i s i o n of the p r o j e c t i l e with a h igh -? target nucleus. The la rge i c c o i l v e l o c i t i e s given to product nuclei al low for l i f e t im e determinations of exc ited s ta te s in the 10“ l c - l ( r 1<< second range by r e c o i 1-d i s tance Doppler s h i f t and Doppler-broadened l ineshape a n a l y s i s . The high angular momentum imparted to a reaction product leads to the production of nuclei in sp in s ta te s greater than fjOfi, and s tud ie s of the de -exc i ta t ion of these s ta te s by continuum y - rays g ives information about the moment o f i ne r t ia and the shape of these nuc le i as a funct ion of spin, This I s one of the most recent and e x c i t i n g f i e l d s of' nuclear s t ru c tu re , and inc ludes a number of evo lv ing techniques, such as m u l t i p l i c i t y f i l t e r s , 7 -ray sum spectrometers, y - ray po la r im e te r s , Compton-suppressed spectrom­ eters , and the use of convcrs ion -e lectron spectrometers ir. the continuum region, Heaviest Hement Research A. Ghiorso, J, M. Ji itschke, M. Numia The ob ject ive of t in s project i s to extend our knowledge of the heaviest elements, Hew technologies and new c a p a b i l i t i e s of the LuperHILAC make i t p o s s ib le in p r in c ip le to create new elements, but many ba rr ie r s present themselves. The world-wide f a i l u r e of recent attempts to p ro ­ duce superheavy elements via fusion or other types of react ions has been quite d i sappo in t in g and makes i t c lear that a better understanding of the basic phys ics of heavy-ion c o l l i s i o n s is nocded. A s ta r t in th i s d i re c t ion has been made by our recent experiments with the doubly-magic nuc le i 4,0Ca, ,,f,Ca, and ? 0 "Pb. Another approach to the hypothesized superheavy element “i s land " is to t ry and extend the “co a s t l i n e " above element 106 so as to better under­ stand the reasons for the f a i l u r e s to reach the is land, The time-tr ied technique of bombarding the heaviest element ava i lab le with the l i g h te s t s u i t ab le p r o je c t i l e s u f f e r s from the handicap of m in iscu le cross sect ion but can be used for at lea s t element 107. An a l ternate method i s the use cf heavier p r o j e c t i l e s to bombard ?0GPb and ? °°Bi and th i s tech­ nique w i l l be explored soon, A la rge ly unexplored path to the synthe s i s o new isotopes and perhaps even new elements has emerged through the discovery of the deep in e l a s t i c react ions, Since many of these nuc l ides w i l l be sh o r t - l i v e d and w i l l decay predominantly by spontaneous f i s s i o n , the i r id e n t i f i c a t i o n as to A and 1 w i l l present a d i f f i c u l t experimental problem, We are therefore preparing an instrument which w i l l y i e l d information about the mass of a nucleus before i t decays, This device w i l l be e spe c ia l l y helpful f o r those cases where the angular d i s t r i b u t i o n of the reaction products i s too broad for use in conventional magnetic instruments, RHCf. B jm U Y .LABOVJORY........................................................ WS.OOO ear Science Division* -92- Instrumentation Service for Nuclear Science F. S. Goulding, G. Haller, D. Landis, M, Maier, C. Maples, R, Pehl The scope of this program is to provide general services in connection with all electronic instruments and computers used in Nuclear Science Division programs. In addition to maintenance of a ll community equip­ ment ( i.e ., shared by groups), this includes operation of an equipment pool, maintaining f i le s of drawings and records on instruments and providing operating manuals and a consulting service for a ll aspects of instruments and detectors used in research programs. The experi­ mental programs covered include LBL and outside users at the SuperHlLAC, 88" Cyclotron and the Bevalac accelerators. A major component in this project is the provision of a software system and service for the Mod, Comp. IV data acquisition systems at the SuperHlLAC (three systems) and the 88" Cyclotron. This work has recently been expanded to include the development of general-purpose data acquisition systems for use in experiments at the Bevalac. LAWRENCE BERKELEY LABORATORY ........................................................... $370,000 * Nuclear Science~l)ivision * Additional funding provided under Nuclear Sciences.* $75,000