Calculation of -delayed fission and neutron emission probabilities with the use of gross theory and KTUY mass formula

Tachibana, Takahiro*; Koura, Hiroyuki   ; Chiba, Satoshi

Probabilities of the -delayed neutron emission are important information for decay heat calculation and, recently, the effect of the -delayed fission to the r-process nucleosynthesis is a quite interesting topic. We make an improvement of the calculation of the probabilities of -delayed fission and neutron emission for nuclei in the region far from the experimentally known nuclides. The probabilities of -delayed fission and neutron emission are estimated by using the gross theory of nuclear -decay. This theory includes the allowed (Fermi and Gamow-Teller) and first-forbidden transitions. In order to estimate the decay width and , we improve the calculation of nuclear level density formula by Kawano et. al. to take into account the effects of collective motion. We adopted the KTUY mass model for obtaining -values, neutron separation energies and fission barrier heights. The shell and the paring energies are also obtained by KTUY mass model for the calculation of the nuclear level density. We will apply these data to an r-process network calculation and briefly discuss the effect of nuclear fission to the r-process abundance in the presentation.