The total kinetic energy release and fragment mass distributions in the fast neutron induced fission of actinide nuclei

The total kinetic energy release and fission mass distributions for the fast neutron (En=3-100 MeV) induced fission of 232Th, 233U, 235U, 237Np, 239Pu, 240Pu, 242Pu and 241Am have been measured using the LANSCE facility. The fission fragments were detected using Si PIN diode detectors. The actinide targets were made by vapor deposition leading to high quality targets. The TKE distributions were Gaussian in shape. In the case of 233U and 235U, our measurements agree with prior work. Our measurements for 232Th are unique. Our data agree with Viola scaling. The variances of the TKE distributions are larger than predicted by conventional models of scission. The heavy mass peak remains constant in position due to the influence of the N=88 and Z=50 shells. The GEF model predictions agree with the data in general as do the CGMF model predictions.