Fission fragment mass distribution in 32 S + 144 Sm

The fission fragment mass distribution (FFMD) is one of the important observables to understand the fusion fission mechanism involved in the heavy ion induced reactions. The fusion fission process is guided by the potential energy landscape of the fissioning system. The symmetric fission of actinide fissioning systems at relatively higher excitation energy could easily be explained by liquid drop model (LDM). Incorporation of shell correction in LDM could explain the asymmetric nature of the fission fragment mass distribution at low excitation energy. A few years back, Andreyev et al., reported asymmetric fission with mass ratio 100/80 in -delayed fission of Hg [1]. Though, conventional shell effect predicts the symmetric splitting in Zr with semi magic configuration (N=50, Z=40). This observation prompted a series of theoretical and experimental investigations. Theoretical calculations by Moller et al. showed that this behaviour is not only restricted to Hg but also is expected for many other nuclei in this mass region ~180 [2]. With an objective to investigate the nature of fission fragment mass distribution around the mass region A~180, measurement has been carried out in S+Sm reaction with excitation energy of the compound nucleus (Pt) in the range of 40-50 MeV.