Proton-beam profiling using radiophotoluminescent glass-based hybrid radiation monitoring system

Radiation detectors are generally classified as active or passive, each offering distinct advantages for beam monitoring applications. In proton-beam radiation therapy, accurate beam profiling and long-term dose recording are essential for quality assurance and system optimization. In this paper, a hybrid radiation monitoring system that combines both active and passive approaches based on radiophotoluminescent (RPL) glass is presented. Custom silver-doped phosphate RPL glass was fabricated and irradiated with a 45-MeV proton beam. Optical luminescence induced by proton irradiation was captured using a UV excitation source and a CMOS camera system, and the beam profiles were analyzed using an image processing technique. The measured Bragg-peak position showed less than 1% deviation from Geant4-based Monte Carlo simulation results, indicating a high spatial accuracy. The RPL glass exhibited a linear dose response up to approximately 400 Gy, above which saturation effects were observed. Luminescent centers remained stable for more than 1 month after the irradiation and were fully reset by thermal annealing at 400 °C for 1 h, thereby enabling repeated use. These results indicate that RPL glass can provide both direct optical visualization and passive dose recording within a single platform. Thus, this approach offers a practical and reusable method for proton-beam profiling, with potential applications in quality assurance, accelerator diagnostics, and radiation research.