TL and EPR studies of CaSO4:Dy phosphor to investigate its efficacy in measurement of food irradiation dose at sub-ambient temperatures

The effects of sub-ambient temperatures of irradiation and dose response of CaSO4:Dy phosphor was investigated. The irradiation dose in the range 0.5–7.0 kGy was chosen to meet the requirement of commercial food irradiation at low temperature. Commercially available phosphor showed no significant change in glow curve structure with low temperature of irradiation. In order to enhance the sensitivity of the low temperature glow peak (142 °C), the phosphor was subjected to different post-preparation thermal treatments at 700–900 °C. The change in glows and improvement in dose response characteristics were explained by Electron Paramagnetic Resonance (EPR) spectroscopy. At sub-ambient temperature of irradiation, the behavior of thermally treated CaSO4:Dy phosphor with increasing dose revealed improved linear response of the low temperature glow peak and could be an efficient dosimetry system for the food commodities irradiated at low temperatures.