Validating The Bohr Hypothesis: Comparing Fission-Product Yields From Photon-Induced Fission Of Pu-240 And Neutron-Induced Fission Of (Pu)-P-239

The Bohr hypothesis, one of the most fundamental assumptions in nuclear fission theory, states that the decay of a compound nucleus with a given excitation energy, spin and parity is independent of its formation. Using fission product yields (FPYs) as a sensitive probe, we have performed new high precision test of the combined effects of the entrance channel, spin and parity on the fission process. Two different reactions were used in a self-consistent manner to produce a compound Pu-240 nucleus with the same excitation energy: neutron induced fission of Pu-239 at E-n = 4.6 MeV and photon-induced fission of Pu-240 at E-gamma = 11.2 MeV. The FPYs from these two reactions were measured using quasimonoenergetic neutron beams from the TUNL's FN tandem Van de Graaff accelerator and quasimonenergetic photon beams from the High Intensity gamma-ray Source (HI gamma S) facility. The first results comparing the FPYs from these two reactions will be presented. Implications for validating the Bohr hypothesis will be discussed.