Abstract:
Background: The precompound emission process in light-ion fusion interactions has been a topic of considerable interest to nuclear physicists for many years. Although widespread theoretical and experimental efforts
have been devoted to understand the reaction dynamics of precompound emission, no systematic study has been
carried out to determine the driving input parameters in such reactions.
Purpose: The importance of this study has large impact on reaction dynamics. In order to get parameters
describing the precompound emission, excitation functions have been measured by using an α-particle beam
on 141Pr target nuclei. Further, a sensitive analysis of excitation functions has been performed to investigate the
systematics of the precompound process with mass number of target nuclei.
Method: The off-line γ -ray-spectrometry-based activation technique has been used for the measurement of
the excitation functions. The presently measured excitation functions on the system α + 141Pr (and those
experimental values taken from literature on the α + 51V, α + 55Mn, α + 93Nb, α + 121Sb, and α + 123Sb
systems) have been analyzed within the framework of compound and precompound emissions by using model
code ALICE.
Results: The analysis performed by using code ALICE with the same set of precompound parameters indicates
that the experimentally measured excitation functions could be reproduced only when the precompound
emission, simulated theoretically, has been taken into account. The influence of various important precompound
parameters of the code ALICE with their physically accepted values for these systems has been judged and a
systematics on precompound emission process is achieved with mass number of the target nuclei.
Conclusions: The developed systematics for α-induced reactions on target nuclei 51V, 55Mn, 93Nb, 121Sb, 123Sb,
and 141Pr indicates that the precompound process is governed by the excitation energy available to the nucleons
at the surface the composite systems. Furthermore, mass number of the target nuclei may also play an important
role in precompound process at low projectile energies.
