Thermoluminescent responses of Li3B7O12:Cu to proton beam

A thermoluminescent (TL) phosphor Li3B7O12:Cu was irradiated by a proton beam at NIRS-HIMAC in Japan. Irradiation was performed at different water-equivalent depths using range shifters made of polymethyl methacrylate. The thermoluminescent responses of Li3B7O12:Cu were analysed, focusing on the TL efficiency and glow curve. The irradiated samples were heated from room temperature to 200°C at 0.16°C s(-1). The high-temperature area of the glow curve under proton irradiation changed in comparison with that under (60)Co gamma-ray irradiation. The relative TL efficiency of the main peak slightly varied between 0.8 and 1.1. The relationship between the relative TL efficiency of the main peak and the high-temperature area ratio (HTR) value, the relative TL ratio of the main peak to the high-temperature area, showed approximate linearity for proton dosimetry. Using correction based on the HTR method, the TL phosphor Li3B7O12:Cu can become a useful dosimetric tool for therapeutic proton beams.