This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

Collins, J.C.

Daehnick, W.W.

Foster, C.C.

Friesel, D.L.

Jacobs, W.W.

Jones, W.P.

Kailas, S.

Schwandt, P.

English

IUScholarWorks (Indiana University)

DEUTERON ELASTIC SCATTERING CROSS-SECTION MEASUREMENTS FOR S i ,  4 0 ~ a  AND 2 0 8 ~ b  AT 79 MeV C.C. Fos ter ,  J . C .  Col l ins ,  D.L. F r i e s e l ,  W.W. Jacobs, W.P. Jones, S. Kai las ,  P. Schwandt, and W.W. Daehnick* D i f f e r e n t i a l  cross-sect ion angular  d i s t r i b u t i o n s ,  i n  t he  angular  range 6' O L  5 90°, f o r  e l a s t i c  s ca t -  t e r i n g  of 79.2 MeV deuterons from S i ,  4 0 ~ a  nd 2 0 8 ~ b  have been measured using the  QDDM spectrograph.  An ex te rna l  monitor counter  which cons is ted  of a  one inch th i ck  Na(1) s c i n t i l l a t o r  coupled t o  a  RCA 8575 photo- m u l t i p l i e r  tube wi th  a  s p e c i a l l y  designed r a t e  insens i -  t i v e  tube base was developed f o r  t h i s  work. I n  addi- t i on ,  a  newly designed i n t e r n a l  Faraday Cup, s p l i t  i n t o  l e f t  and r i g h t  ha lves ,  was used t o  s t o p  the  beam i n  t h e  spectrograph s c a t t e r i n g  chamber. A computer code, which samples t h e  l e f t - r i g h t  cu r r en t  unbalance from t h i s  cup, au tomat ica l ly  a d j u s t s  t h e  cu r r en t  i n  t h e  l a s t  ho r i zon ta l  beam-line s t e e r e r  t o  keep the  beam centered on the  Faraday Cup. Measurements of e l a s t i c  alpha Ed - 79.2 MeV ELASTIC SCATTERING A EXPERIMENT - PREDICTION (Ed = 80 MeV) O.M. PRESCRIPTION "E" ' CHILDS And DAEHNICK s c a t t e r i n g  a t  12  t o  18  MeV have been made a t  t h e  Universi ty of P i t t sburgh i n  order  t o  b e t t e r  determine t a r g e t  th icknesses  f o r  t he  t a r g e t s  used i n  t h e  e l a s t i c  deuteron study.  Data reduct ion  is s u f f i c i e n t l y  complete a t  t h i s  time t o  al low presenta t ion  i n  t h i s  r epo r t  of prelimin- a ry  absolu te  cross-section angular  d i s t r i bu t ions .  The r e s u l t s  f o r  S i  and 4 0 ~ a  r e  shown i n  Figures 1 and 2  (with f 5% r e l a t i v e  and + 10% absolu te  u n c e r t a i n t i e s )  and a  pre l iminary  r e l a t i v e  cross-sec t ion  angular  d is -  t r i b u t i o n  (+ 5% r e l a t i v e  uncer ta in ty)  f o r  2 0 8 ~ b  i s  shown i n  Figure 3 .  P r i o r  t o  measurement of these  d i s t r i b u t i o n s  o p t i c a l  model p red i c t i ons  based on t h e  g lobal  parameter p r e s c r i p t i o n  "El' of Childs and ~ a e h n i c k l )  were made. These a r e  shown a s  a  s o l i d  l i n e  4 0  Ca (d,d140ca Ed  = 79.2 MeV ELASTIC SCATTERING A EXPERIMENT - PREDICTION (Ed = 8 0  MeV ) O.M. PRESCRIPTION "E' CHILDS And DAEHNICK I&*' 1; i o  ;o ;o ;o A 7; :o % A 1  B, (DEGREES ) F i g u r e  I .  F i g u r e  2 .  I I I I , a r e  included i n  Table 1. I 208 ~ b ( d , d ) ~ ' ~ ~ b  E d  = 79.2 MeV t ELASTIC SCATTERING 1 -A- EXPERIMENT 1 - PREDICTION (Ed = 80 MeV) O.M. PRESCRIPTION "E* CHILDS And DAEHNICK 0 10 20 30 40 50 60 70 80 90 8,. (DEGREES) Table 1. Global Deuteron Opt ica l  Model Parameter P re sc r ip t ions  .Q F i g u r e  3. VsO= 5.5 on each f igu re .  I n  the  case  of 2 0 8 ~ b ,  t h e  angular  d is -  t r i b u t i o n  has  been normalized t o  t h e  p red i c t i on  a t  ecm = 27 degrees.  The qua l i t y  of agreement between predic ted  and measured d i s t r i b u t i o n s  is  seen t o  be reasonably good f o r  S i  and 4 0 ~ a ,  although t h e r e  a r e  regions of  f a i r l y  l a r g e  disagreement. I n  t he  case  of 2 0 8 ~ b ,  t he re  is a  peak near 8 = 33 degrees i n  t he  measured angular  cm d i s t r i b u t i o n  which is  not  seen i n  t h e  predic ted  d is -  t r i b u t i o n .  Recent ca l cu l a t i ons  show t h a t  this peak is  b e t t e r  reproduced i f  parameter s e t  "C" of Childs and ~ a e h n i c k l )  is used. As soon a s  d a t a  reduct ion  is com- p le ted  a  systematic o p t i c a l  model ana lys i s  of  these  da t a  w i l l  be performed. A t  p resent  the  r e s u l t s  indi -  c a t e  t h a t  one can obta in  somewhat reasonable deuteron o p t i c a l  model parameters from the  p re sc r ip t ions  "El1 and "C" of Childs and Dachnick extended from the  energy range (17 to  52 MeV) of t h e i r  d a t a  base t o  80 MeV and t h a t  p re sc r ip t ion  "C" is probably the  b e t t e r  p re sc r ip t -  i on  t o  use. For convenience p re sc r ip t ions  "c" and "E" * a l l  imaginary depths Wv, WD a r e  e i t h e r  a s  s t a t e d  above o r  zero,  whichever is g rea t e r .  *University of P i t t sburgh,  P i t t sburgh,  PA 15260 1 )  J . D .  Childs,  Ph.D. Thesis ,  Univ. of P i t t sburgh,  1976 (unpub .) . 

Deuteron Elastic Scattering Cross-Section Measurements for Si, 40-Ca, and 208-Pb at 79 MeV

https://scholarworks.iu.edu/dspace/bitstream/2022/2923/1/iucf_1978_32-33.pdf

Deuteron Elastic Scattering Cross-Section Measurements for Si, 40-Ca, and 208-Pb at 79 MeV

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