INDC(IND)-35G - IAEA Nuclear Data Services

-32-
£>J is a factor which arises due to proton neutron distinguishability.
§. is the single particle level density and is taken to be ft/13.Atia
the reduced mass of V-par*Jole and Sy is its apin. T>> is the life time
of n-exciton state and is given by
where \ is the ttansition rate to the next higher excitcn state and
is given by • . _—-»
IKF is the average squared matrix element ana is taken to bev
dependent on average energy per exciton as given by Kalbach'-'
in equation (4) is given as follows,
Sn in equation (2) is the term responsible for depletion and is
given by
in equation (1) is related with Dn as follows
Inverse reaction cross sections have beerL.obtained by the parametrisation
developed by Chatterjee *t al B ' to get Wilmore-Hodgaon ^)
optical mode' reaction cross sections. At energy lower than 2 MeV
their parsv ; nation is not accurate. 9@pce at these energies an
expression --•,- in by Blelt and Weisskopf 10 ' is usedby matching the
cross Hectic " *t 2 MeV.
Equilibrium Component
The equilibrium component is calculated according to the Weisskopf
model neglecting angular momentum. The probability of neutron emission
with energy € is given as follows.
p ~ e. ) is the level density at the excitation
energy U and is given by
- C e
C is taken to be constant, any slow variation in C is neglected, a