Proton Dose Dependence of Radio-photoluminescence Properties of Ag-doped Na–Al Phosphate Glasses

Ag-doped Na-Al phosphate glasses have been used in commercial personal dosimeters for X-rays, γ-rays, and β-rays owing to their radio-photoluminescence (RPL) properties.The RPL behavior in this material when irradiated with high-linear-energy-transfer (LET) radiation has been investigated; however, there are unclear points such as LET quenching.In this study, the proton (3.14 MeV, 22.1 keV/μm) dose dependence of the RPL properties of Ag-doped Na-Al phosphate glasses was investigated as a first step to elucidate the RPL mechanism under high-LET exposure.The optical absorption spectra suggested the formation of Ag 0 , Ag 2+ , Ag 3 2+ , and the phosphorous-oxygen hole center (POHC) by proton irradiation.In the photoluminescence spectra with an excitation wavelength of 310 nm, broad emission peaking at 650 nm corresponding to Ag 2+ and Ag 2 + was observed after proton irradiation.Furthermore, the formation of Ag 2+ , Ag 2 + , POHC, and peroxy-radical by proton irradiation was revealed in the electron spin resonance spectra.Interestingly, the peroxy-radical signal in Ag-doped phosphate glasses has not been observed in previous studies where the glasses were irradiated with high doses of low-LET radiation, and it is possible that the peroxy-radical is formed only when the glasses are irradiated with high-LET radiation.