- 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, and 242Pu have been measured using the LANSCE facility. The neutron energies were deduced from time-of- flight measurements. The fission fragments were detected using Si PIN diode detectors, giving us the fragment energies. The actinide targets were made by vapor deposition leading to high quality targets, that were thin and uniform with reduced impurities. Corrections were made to the data for pulse height defect and the fragment energy loss in the target and its backing. The TKE distributions were Gaussian in shape and their mean value as a function of incoming neutron energy could be fitted with second order polynomials. 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 constant position of the heavy mass peak is interpreted as being 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.
|Funding Statement (additional comments about funding)
- The work described in this paper is the result of the efforts of several students and post-doctoral fellows in my research group. The principal contributors were J. S. Barrett, J. King, R. Yanez, A. Pica, A. Chemey, M. Silveira, and L. Yao. Financial support of the research was provided by the Stockpile Stewardship Academic Alliance, the U.S. Dept. of Energy, Office of Nuclear Physics, and the Lawrence Livermore National Laboratory. This manuscript is based upon work supported in part by the U.S. Dept. of Energy, Office of Science, Office of Nuclear Physics, under award number DEFG06-97ER41026.