Transparent protective materials are an important component of nuclear radiation protection equipment and a key factor in reducing radiation damage to the eye lenses of radiation workers.

This study aims to prepare polymethyl methacrylate (PMMA) doped with gadolinium element and explore its shielding properties against neutron and gamma rays.

Firstly, samples of PMMA doped with gadolinium element were prepared by intrinsic polymerization of gadolinium-containing PMMA, and the PMMA samples with different Gd(MA)₃ content were applied to both experimental test and simulation calculation. Then, the ²⁵²Cf neutron source (moderated by 12 cm polyethylene) and ³He counting tube detector were employed to test the effect of Gd(MA)₃ content on the neutron shielding performance of samples whilst the ²⁴¹Am gamma source and high-purity germanium (HPGe) detector were used to explore the effect of different Gd(MA)₃ content on the 59.5 keV γ ray shielding performance of samples. Simultaneously, the MCNP software was applied to the validation of gadolinium-containing PMMA neutron shielding performance experiments, and analyze the effect of different Gd(MA)₃ content on the neutron shielding performance of PMMA against ²⁵²Cf. Finally, both thermogravimetric analysis (TGA) curves and tensile properties of PMMA doped with different Gd(MA)₃ contents were compared and analyzed.

The results show that the shielding properties of the PMMA against ²⁵²Cf neutrons (moderated by 12 cm polyethylene) are continuously improved with the increase of Gd(MA)₃ content. However, when the Gd(MA)₃ content exceeds 10%, no obvious improvement in shielding performance is observed whereas the shielding performance against gamma rays is improved continuously. The PMMA containing 10% Gd(MA)₃ has absorption cross-section of for ²⁵²Cf neutrons whilst linear attenuation coefficient of PMMA containing 30% Gd(MA)₃ for 59.5 keV (²⁴¹Am) gamma ray is 2.10 cm^-1. With the increase of the thickness of PMMA, its neutron shielding performance increases exponentially, 90.2% of ²⁵²Cf fast neutrons are shielded by PMMA with a thickness of 10 cm and a Gd(MA)₃ content of 10%.

PMMA doped with gadolinium can effectively enhances its shielding properties against thermal neutrons and gamma rays while maintaining good visible light transmittance and improving the heat resistance of the material, but its mechanical strength is reduced. The results of this study provide valuable information for the development of apparent neutron/gamma shielding equipment.