Evaluation of delayed neutron yields and time spectra from photofission of ²³⁸U induced by <i>Bremsstrahlung</i> photons below 9 MeV

Few data exist regarding the yields and time spectra of delayed neutrons from photofission reaction on actinides. In this paper, we report characteristics both six-group eight-group neutron models for 238 U induced by a Bremsstrahlung photon spectrum with an end-point energy at 9 MeV. This study was conducted using MeV linear electron accelerator housed SAPHIR platform located CEA Paris-Saclay, France. A reference sample depleted uranium positioned inside detection block, previously designed optimized Monte Carlo simulation, made high-density polyethylene covered cadmium including ten one meter-long 3 He proportional counters. Based consistent set half-lives proposed Spriggs et al. as early 1999 neutroninduced fission, our description in eight groups is first published photofission. These new results bring valuable information to scarce available literature represent useful inputs development photofission-based nuclear measurement systems they meet significant interest fields data, radioactive waste package characterization security-related applications.