Applicability and performance of an imaging plate at subzero temperatures

The performance of imaging plates (IPs) has not been studied at temperatures lower than 0. °C. In the present study, an IP was irradiated with gamma rays emitted from the mineral monazite at temperatures between -80 and 30. °C to determine its fundamental properties. The IP response as a function of irradiation time was found to be linear, suggesting that the IP works properly at low temperatures. Fading, an effect which should be considered at temperatures of more than 0. °C, was not observed at -30 and -80. °C. Furthermore, the fading-corrected PSL value of the IP irradiated at -80. °C was lower than at other temperatures (30, 5 and -30. °C). This can be explained by thermostimulated luminescence (TSL). Since the only intensive TSL peak in the temperature range from -80 to 30. °C is present at about -43. °C, some of the electrons trapped at F centers recombine with holes through the process of TSL before the stored radiation image is read out at room temperature. This finding suggests that the apparent sensitivity of the IP is lower at -80. °C although it is similar to sensitivities between -30 and 30. °C. This low sensitivity should be corrected to perform quantitative measurements.