Build-up of radiophotoluminescence (RPL) in Ag-doped phosphate glass in real-time both during and after exposure to ionizing radiation: A proposed model.

ABSTRACT The build-up of radiophotoluminescence (RPL) from Ag-doped alkali-phosphate glass (from Chiyoda Technol Corporation, Japan) was measured both during and immediately following irradiation. The post-irradiation build-up curve was measured at several different temperatures and could be described by the sum of two exponential functions of time. The two processes are thermally activated, with activation energies of 0.45 eV and 0.17 eV, and their relative contributions were observed to behave in opposite senses as the temperature increases. Thermal quenching of the RPL signal with increasing temperature was also observed. The real-time RPL signal during irradiation could be described by the convolution of an intrinsic growth function and the build-up curve. A model is proposed wherein Ag2+-pairs and Ag2+ centers contribute to the RPL signal. A set of non-linear differential equations was written to describe the build-up process and numerical solution of these equations yielded simulated results which qualitatively matched the observed experimental data.