Investigation of Radiation Damage in Iron Phosphate Glasses by Soft X-Ray Absorption Spectroscopy: A Powerful Tool for Surface Characterization

Abstract

Soft X-ray absorption spectroscopy, at the Fe L2,3 edge, in total electron yield mode (TEY), was employed to study radiation stability of iron phosphate glasses. Iron phosphate glasses are the potential matrix for immobilisation of high-level radioactive waste (fission products and minor actinides) from nuclear fuel reprocessing. Due to radioactive nature of waste, the radiation stability of immobilising matrix is a point of concern. In order to investigate radiation stability of the phosphate glasses, the surrogate method of ion irradiation was used. Fe2O3–P2O5 glasses, with and without B2O3 modification, were bombarded with Au+1 ions (Energy: 750 keV; Fluence: 2 × 1015 ions/cm2). Due to shorter penetration of ions inside matrix, most of the damage arises within a few 100 nm of the surface. Therefore, surface sensitive technique SXAS in TEY is employed to probe ion beam induced damages close to surface. It is found that boron-doped iron phosphate glass is more radiation-resistant than base iron phosphate glass.