Gamma Ray Spectra from Thermal Neutron Capture on Gadolinium-155 and Natural Gadolinium

Abstract

Natural gadolinium is widely used for its excellent thermal neutron capture cross section, because of its two major isotopes: ${}^{155}$Gd and ${}^{157}$Gd. We measured the $\gamma$-ray spectra produced from the thermal neutron capture on targets comprising a natural gadolinium film and enriched ${}^{155}$Gd (in Gd${}_2$O${}_3$ powder) in the energy range from 0.11 MeV to 8.0 MeV, using the ANNRI germanium spectrometer at MLF, J-PARC. The freshly analysed data of the ${}^{155}$Gd(n, $\gamma$) reaction are used to improve our previously developed model (ANNRI-Gd model) for the ${}^{157}$Gd(n, $\gamma$) reaction, and its performance confirmed with the independent data from the ${}^{\mathrm{nat}}$Gd(n, $\gamma$) reaction. This article completes the development of an efficient Monte Carlo model required to simulate and analyse particle interactions involving the thermal neutron captures on gadolinium in any relevant future experiments.

14 pages. arXiv admin note: text overlap with arXiv:1809.02664