Total prompt γ-ray emission in fission

C.Y Wu,H.Y Lee,A Chyzh,R.A Henderson,J.L Ullmann,E Kwan,J.M O'Donnell,R.C Haight,A.C Hayes-Sterbenz,T.A Bredeweg

doi:10.1051/epjconf/201714604037

Abstract

The total prompt γ-ray energy distributions were measured for the neutron-induced fission of 235U, 239,241Pu at incident neutron energy of 0.025 eV–100 keV, and the spontaneous fission of 252Cf using the Detector for Advanced Neutron Capture Experiments (DANCE) array in coincidence with the detection of fission fragments by a parallel-plate avalanche counter. Corrections were made to the measured distribution by unfolding the two-dimension spectrum of total prompt γ-ray energy vs multiplicity using a simulated DANCE response matrix. A summary of this work is presented with the emphasis on the comparison of total prompt fission γ-ray energy between our results and previous ones. The mean values of the total prompt γ-ray energy ⟨Eγ,tot⟩, determined from the unfolded distributions, are ∼20% higher than those derived from measurements using single γ-ray detector for all the fissile nuclei studied.

Highlights

The total prompt γ -ray emission in fission accounts for about 40% of the total energy released by γ -ray emission that makes up about 10% of the total energy released in reactor core
We reported the total prompt γ -ray energy distributions for those isotopes, obtained by unfolding the measured two-dimensional spectrum of total γ -ray energy vs multiplicity [15]
The prompt γ rays emitted in fission were detected by the Detector for Advanced Neutron Capture Experiments (DANCE) array in coincidence with the detection of fission fragments by a compact parallel-plate avalanche counters (PPAC) [12]

Summary

Introduction

The total prompt γ -ray emission in fission accounts for about 40% of the total energy released by γ -ray emission that makes up about 10% of the total energy released in reactor core. The heating in nuclear reactors attributed to the total γ -ray emission in fission is underestimated up to 28% using the evaluated data for the main reaction channels, 235U(n,f) and 239Pu(n,f) [1]. This discrepancy is significantly greater than 7.5%, an upper bound of the uncertainty deemed necessary to adequately model the heat deposit in the fuel core [2, 3]. The majority of measurements made for the prompt γ -ray emission in fission always employed a single or a few γ -ray detectors. A single NaI detector was used by Verbinski et al [4] more than 40 years ago and the cerium-doped LaBr3, CeBr3, and LaBr3 detectors were used recently by Billnert et al [1] and Oberstedt et al [5, 6]

Methods

Results

Conclusion