Determination of fission product yield distribution in ²³⁵U(n_th,f) and its detailed comparison with GEF calculations

The availability of the General Fission (GEF) code helps in the reliable determination of fission product (FP) yields, angular momentum distributions, isomeric yields and various fission parameters. The information obtained by the GEF code can be used for a detailed comparison with experimentally obtained yields to investigate the role of single particle effects in governing the yields of fission products in the fission of actinides. In the present study, thermal neutron induced fission of ²³⁵U reaction was carried out followed by off-line gamma-ray spectrometry to measure the yields of the FPs for comparison with the prediction of the GEF code. In the present study, a special emphasis has been given to the short-lived fission products to expand the range of neutron and proton numbers of the fission products for a detailed comparison with calculations of the GEF code to investigate the role of single particle effects. The present calculations consider various modes of decay such as beta decay, partial beta decay to isomers, and beta delayed neutron emission. The output obtained by the code was found to be in good agreement, on the average, with the experimental data. However, a strong deviation was observed around N~88, indicating stronger role of N~88 shell than the prediction of the GEF code. An enhancement in the fission product yield compared to the prediction of the GEF code was also observed near the symmetric mass region. Further study near Z~54 region using the data from radiochemically separated samples and determination of overall mass distribution is in progress