GdO is often used as an absorber in nuclear fuel shielding because of its excellent neutron absorption capacity. However, Gd element releases prompt gamma rays when absorbing neutrons, which threatens the safety of personnel and equipment. In this paper, a new absorber, GdO@W core-shell powder, is proposed, which can simultaneously absorb thermal neutrons and prompt gamma rays. Firstly, MCNP5 software was used to explore the influence of tungsten layer thickness on γ-ray attenuation ratio, and the thickness of tungsten layer required to shield prompt γ-ray was obtained. Then, in order to explore an effective tungsten plating method, GdO@W core-shell powders were prepared by three methods: powder coverage sintering, sol-gel method and immersion method. The GdO@W core-shell powders prepared by the above three methods were observed and analyzed by SEM and EDS. The results show that the core-shell powder prepared by immersion method is more uniform and dense. Finally, the composition and shell thickness of the GdO@W core-shell powder prepared by immersion method was further studied. The results show that the W layer thickness is about 200–600 nm, and there is a diffusion zone between the shell and the core, resulting in new phases GdWO and GdWO. The prepared GdO@W core-shell powder in this paper.can be used as a co-absorber of neutron and gamma rays for shielding composites.

中文翻译：

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中子和伽马射线共屏蔽吸收剂Gd2O3@W核壳粉末的制备及界面分析

GdO因其优异的中子吸收能力而常被用作核燃料屏蔽中的吸收剂。然而，Gd元素在吸收中子时会释放瞬发伽马射线，威胁人员和设备的安全。本文提出了一种新型吸收剂GdO@W核壳粉末，它可以同时吸收热中子和瞬发伽马射线。首先利用MCNP5软件探究钨层厚度对γ射线衰减比的影响，得到屏蔽瞬发γ射线所需的钨层厚度。然后，为了探索一种有效的镀钨方法，通过粉末覆盖烧结、溶胶凝胶法和浸渍法三种方法制备了GdO@W核壳粉末。采用SEM和EDS对上述三种方法制备的GdO@W核壳粉末进行观察和分析。结果表明，浸渍法制备的核壳粉末更加均匀致密。最后，进一步研究了浸渍法制备的GdO@W核壳粉末的组成和壳层厚度。结果表明，W层厚度约为200-600 nm，壳与核之间存在扩散区，产生新相GdWO和GdWO。本文制备的GdO@W核壳粉末可用作屏蔽复合材料的中子和伽马射线共吸收剂。