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 analysed 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, 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 analyse particle interactions involving the thermal neutron captures on gadolinium in any relevant future experiments.

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来自钆 155 和天然钆的热中子捕获的伽马射线光谱

天然钆因其两种主要同位素：$^{\rm 155}$Gd 和 $^{\rm 157}$Gd，因其优异的热中子捕获截面而被广泛使用。我们测量了由包含天然钆薄膜和富集的 $^{\rm 155}$Gd（在 Gd$_{2}$O$_{3}$粉末）在 0.11 MeV 到 8.0 MeV 的能量范围内，使用 MLF, J-PARC 的 ANNRI 锗光谱仪。$^{\rm 155}$Gd(n, $\gamma$) 反应的最新分析数据用于改进我们先前开发的模型（ANNRI-Gd 模型），用于 $^{\rm 157}$Gd( n, $\gamma$) 反应，其性能得到 $^{\rm nat}$Gd(n, $\gamma$) 反应的独立数据证实。