This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit

Jacobs, W.W.

Jones, W.P.

Marrs, R.E.

Miller, D.W.

Vigdor, S.E.

English

IUScholarWorks

DEEP HOLE STATES I N  THE MIRROR NUCLEI 23Mg AND 2 3 ~ a  
W.W. Jacobs, S.E. Vigdor, W.P. Jones, R.E. Marrs, and D.W. Mi l l e r  
The mir ror  r eac t ions  2 4 ~ g  (d, t )  2 3 ~ g  and i n i t i a l  c a l cu l a t i ons  show a s u b s t a n t i a l  R-dependence 
2 4 ~ g ( d ,  %e) 2 3 ~ a  have been s tudied  a t  Ed = 76 MeV, of t h e  (d , t )  and (d,3He) angular  d i s t r i b u t i o n s ,  and 
wi th  s p e c i a l  emphasis on the  region of e x c i t a t i o n  t h a t  t he  d a t a  f o r  t h e  l a r g e s t  peaks i n  t he  high 
between 8 and 12 MeV, where comparison of e a r l i e r  e x c i t a t i o n  region do appear t o  be c h a r a c t e r i s t i c  of 
(p, d) l land  (d , 3 ~ e )  2 ) r e s u l t s  sugges ts  pronounced R = 1 t r a n s f e r .  This i s  i n  q u a l i t a t i v e  agreement 
d iscrepancies  i n  t h e  spectrum of major l p - she l l  wi th  prel iminary shell-model ca lcula t ions3)  which 
neutron-hole vs.  proton-hole fragments. Comparison p r e d i c t  a concent ra t ion  o f  t h e  l p  -hole s t r e n g t h  312 
of t h e  (d,  t )  and (d, 3 ~ e )  r e s u l t s  should al low us i n  t h i s  region.  The shell-model c a l c u l a t i o n s  per- 
t o  d i s t i n g u i s h  whether t he  previous d iscrepancies  formed t o  da t e  do n o t ,  however, inc lude  Coulomb 
r e f l e c t  t r u e  d i f f e r ences  i n  t h e  s t r u c t u r e  of  t h e  e f f e c t s  i n  t he  r e s i d u a l  i n t e r a c t i o n .  Such ca lcula-  
mir ror  n u c l e i  a t  h igh  e x c i t a t i o n ,  o r  a r i s e  i n s t ead  t i o n s  a r e  needed before  one can judge whether t he  
from d i f f e r ences  i n  r eac t ion  mechanism o r  m i s -  apparent  anomalies a t  high e x c i t a t i o n  i n  f i g .  1 a r e  
i d e n t i f i c a t i o n  of peaks. l i k e l y  t o  r e s u l t  simply from t h e  Coulomb force .  
I n  t h e  present  s tudy,  spec t r a  were obtained up We a r e  planning f u r t h e r  measurements on o t h e r  
t o  a t  l e a s t  1 5  MeV e x c i t a t i o n ,  i n  t h e  angular  range sd-shel l  n u c l e i  a s  p a r t  of a sys temat ic  s tudy of 
6' 5 Olab 5 50°, using both t h e  QDDM spectrograph p-shell  ho l e  s t rength .  We a r e  i n t e r e s t e d  i n  
(% 80 keV re so lu t ion )  and s i l i con -de t ec to r  te lescopes  p a r t i c u l a r  i n  see ing  i f  s i m i l a r  d i f f e r ences  i n  
(%120-150 keV re so lu t ion ) .  Representat ive QDDM high-excitat ion mir ror  s t a t e s  p e r s i s t  i n  n u c l e i  
spec t r a  a r e  shown i n  Fig. 1. These spec t r a  r evea l  c l o s e r  t o  s h e l l  c lo su re  (e. g.,  3 9 ~ a  vs.  3 9 ~ )  . 
considerable fragmentation of  t h e  s t r eng th  i n  t he  
1) D.W. Mi l l e r ,  D.W. Devins, R.E. Pollock,  R. 
region Ex = 8-12 MeV. The l a r g e s t  sharp peaks i n  Kouzes, and V.C. Of f i ce r ,  Bull .  Am. Phys. Soc. 
21, 978 (1976). 
-
t h i s  region (corresponding t o  maximum c r o s s  s ec t ions  
2) M. A r d i t i ,  L. Bimbot, H. Doubre, N. F r a sca r i a ,  
between 0.1 and 1.0 mb/sr) appear t o  have mir ror  J.P. Garron, M. Riou, and D. Royer, Nucl. Phys. 
A165, 129 (1971) ; E. K r h e r ,  G. Mairle,  and 
-
counterpar ts ,  bu t  w i th  s u b s t a n t i a l l y  g r e a t e r  s c a t t e r  G. Kaschl, Nucl. Phys. A.165, 353 (1971). 
(from s t a t e  t o  s t a t e )  i n  t he  Coulomb energy d i f f e r -  3) So m r i ~ u u ,  p r i v a t e  c~mmunication. 
ences and r e l a t i v e  s t r eng ths  than one observes f o r  
s t a t e s  below 6 MeV e x c i t a t i o n  (see  f i g .  1 ) .  
Data reduction and DWBA a n a l y s i s  of t he  r e s u l t s  
a r e  s t i l l  i n  progress.  It i s  encouraging t h a t  
Ed = 76 MeV 
EXCITATION ENERGY (MeV) 
Figure 1. Representative (d, t )  and ( d , 3 ~ e )  spectra acquired with a 2 4 ~ g  target and the QDDM spectrograph. 
The energy resolution is  2 80 keV. The spectra are compositions of several smaller energy b i tes  
taken with different f i e l d  settings; the lowest energy b i t e  has a large background due to  high 
counting rate.  


Deep Hole States in the Mirror Nuclei 23-Mg and 23-Na

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Deep Hole States in the Mirror Nuclei 23-Mg and 23-Na

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