Photoactivated Radiation-Stimulated Luminescence from Scintillator–Silica Disk Pellet for Detecting Tritium β-Particles

Photoactivated radiation-stimulated luminescence (PARSL) from a scintillator–silica disk pellet for detecting β-particles was studied in terms of the pellet structure related to light scattering and trap sites based on excited electron accumulation, and the stimulation of photoactivated 3H β-particles by luminescence was demonstrated. The structure, which had some pores on the disk pellet and its cross section, exhibited excited light scattering on both the surface and inside of the disk pellet, as revealed by scanning electron microscopy and the transmittance of light. The accumulation of electrons excited by light and β-particle irradiations in the trap sites was confirmed by measurements of the thermoluminescence glow curves and emission spectra. The photostimulated luminescence (PSL) from the stored electrons upon β-particle irradiation produced a PSL image. The PARSL from 3H β-particles was demonstrated to be useful for detecting 3H β-particles by pre-light-emitting diode (LED) light irradiation to measure the net count rate, scintillation spectra, and wave-height spectra. The PARSL mechanism was proposed to involve excitation and emission processes. (1) LED light at 365 nm excited scintillator–silica disk pellets, resulting in the emission of fluorescence. (2) Part of the excited electrons were stored at the trap level of the scintillator–silica disk pellets. (3) β-particles stimulated the stored electrons in the trap sites to release luminescence.