Gamma-ray spectra from thermal neutron capture on gadolinium-155 and natural gadolinium
Tomoyuki Tanaka, K. Hagiwara, Enrico Gazzola, Ali Ajmi, I. Ou, Takashi Sudo, Pretam Kumar Das, Mandeep Singh Reen, Rohit Dhir, Y. Koshio, M. Sakuda, A. Kimura, Shôji Nakamura, Nobuyuki Iwamoto, Hideo Harada, G. Collazuol, S. Lorenz, Michael Wurm, William Focillon, Michel Gonin, T. Yano
Abstract
Abstract Natural gadolinium is widely used for its excellent thermal neutron capture cross section, because of its two major isotopes: $^{\rm 155}$Gd and $^{\rm 157}$Gd. We measured the $\gamma$-ray spectra produced from the thermal neutron capture on targets comprising a natural gadolinium film and enriched $^{\rm 155}$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 analyzed data of the $^{\rm 155}$Gd($n, \gamma$) reaction are used to improve our previously developed model (ANNRI-Gd model) for the $^{\rm 157}$Gd($n, \gamma$) reaction [K. Hagiwara et al. [ANNRI-Gd Collaboration], Prog. Theor. Exp. Phys. 2019, 023D01 (2019)], and its performance confirmed with the independent data from the $^{\rm nat}$Gd($n, \gamma$) reaction. This article completes the development of an efficient Monte Carlo model required to simulate and analyze particle interactions involving the thermal neutron captures on gadolinium in any relevant future experiments.