Prompt fissionγ-rays from the reactions²⁵²Cf(SF) and²³⁵U(n_th, f) – new data

Abstract

Abstract. We present new spectral data of prompt -ray emission from the spontaneous fission of 252 Cf. This work was performed in direct response to an OECD/NEA high priority data request. We discuss the impact of our new data on evaluated nuclear data tables not only for this nuclide, but also for 238 U and 241 Pu, which are always produced in a reactor. Furthermore, we will show results from our investigation of prompt -ray emission from the reaction 235 U(n th , f), measured in at the Centre for Energy Research of the Hungarian Academy of Sciences in Budapest, Hungary. Spectral data obtained with three different detectors are consistent and led to an uncertainty on total energy and multiplicity considerably smaller than requested by the OECD/NEA.

Statistical study of the prompt-fission γ -ray spectrum for U238(n, f ) in the fast-neutron region

“…The state-ofthe-art scintillation detectors made of LaBr 3 (Ce) (50.8 mm × 50.8 mm and 76.2 mm × 76.2 mm in diameter and length) have excellent time resolution (300 ps for coincidence γ -rays from 60 Co) and good energy resolution (3% at 661 keV). These detectors were used in several recent measurements of PFGS from different fissioning systems [10,11,13,14] and are used in this work as the main reference detectors to facilitate the comparison. The BaF 2 scintillators had a high detection threshold at around 400 keV so results from these detectors are excluded from the analysis and not presented in this work.…”

“…While recent measurements have focused on thermalneutron-induced fission [10][11][12] and spontaneous fission [13,14], very little PFG information exists for fast-neutroninduced fission [15,16]. In this work PFGS and their average characteristics for fast-neutron-induced fission on 238 Uw e r e studied at energies of 1.9 MeV and 4.8 MeV to gain information on the possible energy dependence of PFG characteristics below second chance fission at 6 MeV.…”