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

Bacher, A.D.

Collins, S.F.

Friesel, D.L.

Jones, W.P.

Li, Qingli

Nann, H.

Officer, V.C.

Shute, G.G.

Spicer, B.M.

Wastell, J.M.R.

English

IUScholarWorks

STUDY OF THREE-PARTICLE-ONE-HOLE STATES I N  14c WITH THE l lB(a , p ) 1 4 ~  REACTION AT 120 MEV 
Qingl i  Li*, H. Nann, A.D. Bacher, D.L. F r i e s e l ,  and W. P. Jones 
Indiana Univers i ty  Cyclotron F a c i l i t y ,  Bloomington, Indiana 47405 
B.M. Spicer ,  G.G. Shute, V.C. Of f i ce r ,  S.F. Co l l ins ,  and J.M.R. Wastell  
Univers i ty  of Melbourne, Aus t ra l i a  
Recently the re  has been considerable  i n t e r e s t  i n  capable of populating f i n a l  s t a t e s  with sp ins  up t o  8-, 
m-par t ic len-hole  s t a t e s .  The most d i r e c t  evidence which r e s u l t  from coupling t h e  t r ans fe r red  (ldgI2) 
1312 
t h a t  a given s t a t e  has a predominant mpnh conf igurat ion t o  the  sp in  312- of the  t a r g e t  nucleus B. 
conf igurat ion comes from m u l t i n u c l e o n  t r a n s f e r  data .  The reac t  ion  products were momentum-analyzed and 
I f  a s t a t e  is s t rong ly  exc i t ed  i n  a s t r i p p i n g  reac t ion  subsequently detected i n  the  f o c a l  plane of the  QDDM 
t h a t  adds m p a r t i c l e s  t o  a t a r g e t  nucleus which magnetic spectrometer with a posi t ion-sensi t ive  h e l i c a l  
contains  the  appropr ia t e  n holes  and is weakly exc i t ed  proport ional  d e t e c t o r  followed by two p l a s t i c  
i n  a l l  simpler r eac t ions ,  then t h a t  s t a t e  c l e a r l y  s c i n t i l l a t o r s  f o r  p a r t i c l e  i d e n t i f i c a t i o n .  The t a r g e t  
contains  a l a r g e  mpnh component. consis ted of a s e l f  -supporting llB f o i l ,  enriched t o  
A recent  study of the  l 3 c ( a S p ) l 6 ~  react ion1 >98%, with a th ickness  of about 0.38 mg/cm2. Three 
(Ea=120 MeV) showed t h a t  only r e l a t i v e l y  few of the  d i f f e r e n t  magnetic f i e l d  s e t t i n g s  were required t o  
known s t a t e s  of 1 6 ~  were s e l e c t i v e l y  exci ted.  The cover the  e x c i t a t i o n  energy region from 6 t o  21 MeV. 
s t r e n g t h  of population of these  s t a t e s  r e f l e c t s  a t  Figure 1 shows a composite spectrum of th ree  such b i t e s  
l e a s t  semi-quant i ta t ively  or  perhaps even quan t i t a -  a t  @lab = 10'. An o v e r a l l  r e so lu t ion  of about 50 keV 
t i v e l y  the  s t r e n g t h  of 3p-3h components i n  them. was obtained. As one can see ,  only a few s t a t e s  a r e  
We extended the  i n v e s t i g a t i o n  of mpnh s t a t e s  with s e l e c t i v e l y  exci ted.  
t h e  (a ,p)  r eac t ion  t o  the  mass-14 system by measuring Angular d i s t r i b u t i o n s  of the  s t ronges t  
angular d i s t r i b u t i o n s  of the  l lB(a ,p)  14c reac t ion  a t  t r a n s i t i o n s  leading t o  s t a t e s  a t  6.73, 7.01, 10.74, 
120 MeV bombarding energy. Due t o  the  momentum 14.87, and 16.44 MeV i n  14c a r e  shown i n  Fig. 2. 
mismatch i n  the  ( a sp )  r eac t ion  a t  120 MeV i nc iden t  Three d i f f e r e n t  angular  p a t t e r n s  can be recognized, 
energy, high-spin s t a t e s ,  3p-lh i n  nature ,  a r e  expected rep resen t ing  th ree  d i f f e r e n t  o r b i t a l  angular momentum 
t o  be s t rong ly  exci ted.  Therefore t h i s  r eac t ion  is  t r ans fe r s .  
CHANNEL NUMBER 
Figure I. Composite proton spectrum of the  l 1 ~ ( a S p ) l 4 c  r eac t ion  a t  120 Mev. 
1 2 1  
Figure 2. Angular d i s t r i b u t i o n s  f o r  t he  l 1 ~ ( a S p ) l 4 c  
r eac t ion .  
Pre l iminary  DWBA c a l c u l a t i o n s  have been performed 
assuming a c l u s t e r  t r a n s f e r .  The quantum numbers of 
t h e  c l u s t e r  were assumed t o  s a t i s f y  the  r e l a t i o n  2N+L=4 
f o r  a {(P1/2)2d5/2) t r a n s f e r ,  2N+L=5 f o r  a 
{P1/2(d5/2)2} t r a n s f e r  and 2N+L=6 f o r  a (d5/2)3 
t r a n s f e r .  The r e s u l t s  a r e  shown as s o l i d  l i n e s  i n  
Fig. 2. The experimental  shapes a r e  q u i t e  we l l  
accounted for .  Microscopic DWBA c a l c u l a t i o n s  a r e  i n  
progress .  
* Permanent address:  I n s t i t u t e  of Atomic Energy, 
Academia S in ica ,  P.O. Box 275, Be i j ing ,  China. 
1)  H. Nann and D.W. Devins, IUCF S c i e n t i f i c  and 
Technical Report, 1981 (p. 80). 


Study of Three-Particle-One-Hole States in 14-C with the 11-B(a,p)14-C Reaction at 120 MeV

https://scholarworks.iu.edu/dspace/bitstream/2022/2715/1/iucf_1982_121-122.pdf

Study of Three-Particle-One-Hole States in 14-C with the 11-B(a,p)14-C Reaction at 120 MeV

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