Mass and isotopic yield distributions of fission-like events in the F 19 + Tm 169 system at low energies

Abstract

In the present work, 22 fission-like residues with mass number 67 A 156 produced via complete fusionfission and/or incomplete fusion-fission have been identified and their production cross sections measured at three projectile energies, viz., 92.0 ± 1.8, 102.5 ± 1.5, and 105.4 ± 1.6 MeV in the 19F + 169Tm system. The absolute cross section of each fission-like residue is measured by recoil-catcher activation technique using offline γ -ray spectroscopy. The data have been analyzed to deduce the parameters for isotopic yield and isobaric charge distributions. The deduced isotopic yields for indium (107,108,109,110mIn) and neodymium (134,135,137,139Nd) isotopes are reproduced by Gaussian distribution and their variance is in good agreement with that reported in literature. The mass distributions of fission-like residues at three energies are also found to be Gaussian peaked, which confirms their production via deexcitation of a compound nucleus through complete fusion-fission and/or incomplete fusion-fission processes. It has been observed that, the mass variance (σ2 M ) values of fission fragments for two different systems, 12C + 169Tm and 19F + 169Tm, at nearly the same excitation energy and angular momentum are distinctly different, indicating the importance of the entrance channel effect in fission reaction dynamics. The theoretically calculated isobaric charge dispersion parameters for these residues are found to be in good agreement with those obtained from the experimental data