This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit

Ahmad, M.

Chant, N.S.

Devins, D.W.

Flanders, B.S.

Friesel, D.L.

Madey, R.

Pella, P.J.

Roos, P.G.

Watson, J.W.

English

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NEUTRON KNOCKOUT REACTIONS 
M. Ahmad, B.S. Flanders, R. Madey, P.J. Pella, and J.W. Watson 
Kent State University, Kent, Ohio 44242 
N.S. Chant and P.G. Roos 
University of Maryland, College Park, Maryland 20742 
D.W. Devins and D.L. Friesel 
Indiana University Cyclotron Facility, Bloomington, Indiana 47405 
Our first (p,pn) neutron knockout experiment was knockout of lp1l2, lp312, and 1s112 neutrons. Figure 2 
performed at the IUCF in July 1980. The targets chosen presents our analyzing power data for these three hole 
for that project were 40~a, 48~a, and *H. The primary states. Also shown in Figs. 1 and 2 are ~istorted-Wave 
objective of this project was to study the "valence" Impulse-Approximation (DWIA) calculations made with the 
neutrons for the calcium isotopes, i.e., the lf712, "THREEDEE" code of Chant et al.4 These calculations 
ld312, 2s112, ana ld5/2 neutron states. A short utilize Elton and Swift wave function^,^ Indiana global 
article1 was published presenting a preliminary optical potentials, and the free p-n t-matrix at the 
analysis of these data; a manuscript describing the final state p-n rest energy. Spectroscopic factors 2, 
completed analysis of these data is in preparation. 4, and 2, respectively, were used for the DWIA 
This work was the Ph.D. dissertation2 project of KSU calculations; these values are the full (2j+l) 
graduate student M. Ahmad, who received his Ph.D. in allowed shell-model strengths. The shapes of the DWIA 
December 1982. 
One of the important results from our July 1980 
(p,pn) experiments on 
that we had the capabi 
4 0 ~ a  and 4 8 ~ a  was the realization 
. 1 4  - g .s .  
.lity to study neutron "deep-hole 
states", i.e., the knockout of inner-shell neutrons in 
addition to valence neutrons. We therefore undertook a 
e x c . = 6 . 2  M e V  
second (p,pn) project at the IUCF in January 1982. 
This experiment was a survey of the (p,pn) reaction on 
targets covering a broad range of A, namely 9 ~ e ,  160, rn 
**~i, 58~i, and 90~r. This second (p,pn) experiment is I I 
eXC.=27.3 M e V  
the Ph.D. dissertation of KSU graduate student P. 
D W I A  
Pella. These measurements were made with a polarized s112 x 2 
beam in a fixed coplanar geometry with 8, - Op = 35O. 
This geometry is optimally momentum-matched for neutron 
2'0 4'0 6'0 8'0 l b o  
separation energies of about 30 MeV; in addition, the T~ ( M e V )  
analyzing power signatures3 for j = R + 112 and Figure 1. Triply differential cross sections for the 
j = -112 states should be strong for this geometry. 160(p,pn)150 reaction at 150 MeV, for knockout of 
1~112, 1~312, and 1sl/2 neutrons. The solid lines are 
Figure 1 shows triply differential cross sections Distorted-Wave Impulse-Approximation (DWIA) 
calculations normalized by spectroscopic factors of 2, 
and analyzing powers for the 160(p,pn)150 reaction for 4, and 2, respectively, which are the full (2j+l) 
allowed shell-model strengths. 
e t .  a ~ , ~  they a r e  q u i t e  d i f f e r e n t .  This r e s u l t  is i n  
e x c .  6 . 2  M e V  
- .2 
Figure 2. Analyzing powers f o r  t h e  160(p,pn)150 
r e a c t i o n  a t  150 MeV f o r  knockout of 1p112, 1 ~ 3 1 2 ,  and 
1s112 neutrons. The s o l i d  l i n e s  a r e  DWIA ca lcu la t ions .  
c ross  sec t ions  a r e  i n  good o v e r a l l  agreement with the  
da ta ;  the  shapes of the  DWIA analyzing powers a r e  not. 
Although both t h e  experimental and DWIA analyzing 
powers show s t rong  j -s ignatures ,  a s  suggested by Jacob 
marked con t ras t  t o  r e s u l t s  from polar ized (p,  2p) 
experiments7s8 where t h e  DWIA c a l c u l a t i o n s  and t h e  d a t a  
appear t o  be i n  good agreement; i t  is  q u i t e  poss ib le ,  
however, t h a t  p a r t  of the  agreement between DWIA and 
experiment f o r  (p,2p) r eac t ions  is imposed by the  
necessary symmetries r e s u l t i n g  from de tec t ion  of 
i d e n t i c a l  p a r t i c l e s  i n  a symmetric geometry. 
Analysis of the  da ta  on t h e  o the r  t a r g e t s  is i n  
progress.  
1)  J.W. Watson, M, Ahmad, D.W. Devins, B.S. Flanders,  
D.L. F r i e s e l ,  N.S. Chant, P.G. Roos, and J. 
Wastel l ,  Phys. Rev. C Z ,  961 (1982). 
2) M. Ahmad, Ph.D. d i s s e r t a t i o n ,  Kent S t a t e  
Univers i ty ,  1982. 
3) G, Jacob, Th.A. J. Maris, C. Schneider,  and M.R. 
Teodro, Nucl. Phys. A257, 517 (1976). 
4) N. S. Chant, P. Kitching, P.G. Roos, and L. Antonuk, 
Phys. Rev. Let t .  43, 495 (1979). 
5) L.R.B. El ton and A. Swif t ,  Nucl. Phys. e, 52 
(1967). 
6) P. Schwandt, H.O. Meyer, W.W. Jacobs, A.D. Bacher, 
S.E. Vigdor, M.D. Kaitchuck, and T.R. Donoghue, 
Phys. Rev. C 26, 55 (1982). 
7) P. Kitching, C.A. Mi l l e r ,  W.C. Mi l l e r ,  W.C. Olsen, 
D.A. Hutcheon, W.J.  McDonald, and A.W. S t e t z ,  Nucl. 
Phys. A340, 423 (1980). 
8) L. Antonuk, P. Kitching, C.A. Mi l l e r ,  D.A. 
Hutcheon, W. J. McDonald, G.C. Neilson, and W.C. 
Olsen, Nucl. Phys. A370, 389 (1981). 


Neutron Knockout Reactions

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Neutron Knockout Reactions

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