This work was supported by National Science Foundation Grant PHY 75-00289 and Indiana Universit

Castaneda, C.M.

Jha, S.

Macias, E.S.

Smith, H.A. Jr.

Ward, T.E.

English

IUScholarWorks

RADIOACTIVE DECAY STUDIES OF NUCLEI PRODUCED FROM BOMBARDMENT BY INTERMEDIATE-ENERGY NEUTRONS 
H.A. Smith, Jr., T.E. Ward, C.M. Castaneda, E.S. Macias*, and S. .Jha** 
We have r ecen t ly  i n s t a l l e d  a pneumatic s o l i d  
t a r g e t  t r anspor t  ( rabbi t )  system f o r  neutron ir- 
rad i a t i on  of gram q u a n t i t i e s  of t a r g e t  ma te r i a l .  
The "rabbit"  p r o j e c t i l e  cons i s t s  of a 2.7-cm del-  
r i n  sphere which contains t he  t a r g e t  ma te r i a l  and 
can be posi t ioned wi th in  1 cm of t h e  back of t h e  
Faraday cup i n  t he  i so tope  production a r e a  beam 
dump. The arrangement is  depicted schematical ly 
i n  Figure 1. Over t he  pas t  few months we have 
WEAWREO NEUTRON FLUX (4") ON TARGET Per PROTON v A  
AS A F W C T l O N  OF PROTON BW ENERGY 
A target I K F  (Beam I n  bemHne) focuss d on 
1w 150 2W 
PROTON BW ENERGY (MeV) 
measured the  neutron f lux,Qn, on t a r g e t  f o r  a v a r i e t y  Figure 2. 
of proton beam energies  and focusing condi t ions ,  mizing the  Faraday cup current .  The r e s u l t s  f o r  
by bombarding A1 samples and using the  known an accumulated s o  f a r  a r e  summarized i n  Figure 2,  
c ross  section1) f o r  t h e  production of 15-hour where we compare t h e  s p e c i f i c  neutron f l u x  
24 2 4 ~ a  by the  2 7 ~ l ( n , o , )  Na reac t ion .  Optimum (n/cm2/sec per  PA of proton beam) wi th  t h a t  ob- 
focus of t he  proton beam on the  center  of  t he  ta ined  a t  t he  Brookhaven Medium-Energy In t ense  
Faraday cup is accomplished by minimizing t h e  Neutron (MEIN) f ac i l i t y1 ) .  It is c l e a r  t h a t  a s  
cur rent  s i g n a l  from an  annular  s t o p  (immediately t he  proton beam energy increases  and t h e  e f f e c t i v e  
upstream of t he  Faraday cup s top )  whi le  maxi- r ad i a t i ng  cen te r  of t he  Faraday cup moves c l o s e r  t o  
t he  t a r g e t  i r r a d i a t i o n  pos i t i on ,  t he  c lo se  geometry 
of  t h i s  f a c i l i t y  r e s u l t s  i n  6 t o  10  times the  
D e l r i n  Sphere 
"Rabbi tl' 
T 
2.7 an 
L 
Sample 
Rabbi 
7 
s p e c i f i c  neutron f l u x  ava i l ab l e  a t  t he  MEIN f a c i l i t y .  
We have performed some prel iminary i r r a d i a t i o n s  
of 15'Tb and 8 9 ~  and have observed the  r e s i d u a l  
a c t i v i t y  o f f - l i ne .  Our ob jec t ive  i n  these  p a r t i c u l a r  
Tube 
bombardments is  t o  "map out" t he  neutron-induced 
I r r a d i a t i o n  
Posi t ion U - ,  Beamaxis 
be in^ Current 
Faraday Cup Current 
y i e l d s  over a wide mass range a s  groundwork f o r  
eventual  production and s tudy of as-yet undiscovered 
neutron-rich i so topes .  Most of  these  l a t t e r  s t u d i e s  
await  t he  i n s t a l l a t i o n  of  more complete radio- 
chemistry f a c i l i t i e s  i n  t h e  t r a i l e r s  southwest of  t h e  
Figure 1. 
i so tope  production area .  
*Washington Universi ty;  S t .  Louis, Mo . 63130 
**University of Cincinnat i ,  Cinc innat i ,  Ohio 45221 
1 )  S. Katcoff e t  a l . ,  Nucl. I n s t r .  Meth. 129, 473 
(1975). 


Radioactive Decay Studies of Nuclei Produced from Bombardment by Intermediate-Energy Neutrons

https://scholarworks.iu.edu/dspace/bitstream/2022/3043/1/iucf_1976_91-92.pdf

Radioactive Decay Studies of Nuclei Produced from Bombardment by Intermediate-Energy Neutrons

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