Validating the Bohr hypothesis: Comparing fission-product yields from photon-induced fission of ²⁴⁰Pu and neutron-induced fission of Pu

¹ Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
² Duke University, Department of Physics, Box 90308, Durham, NC 27708-0308, USA
³ Triangle Universities Nuclear Laboratory, Durham, NC 27708, USA

^* e-mail: silano1@llnl.gov

Published online: 30 September 2020

Abstract

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 ²⁴⁰Pu nucleus with the same excitation energy: neutron induced fission of ²³⁹Pu at E_n = 4.6 MeV and photon-induced fission of ²⁴⁰Pu at E_γ = 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 γ-ray Source (Hl_γS) facility. The first results comparing the FPYs from these two reactions will be presented. Implications for validating the Bohr hypothesis will be discussed.