The gamma ray response of alanine film dosimeters at low temperatures

The response of alanine film EPR dosimeters was studied for low temperature gamma irradiation conditions (77–293K) in the dose interval from 6.3 to 80kGy. It was found that the response of the dosimeter decreases with decreased irradiation temperature and saturates at lower doses for lower irradiation temperatures. The analysis of the EPR signal suggests that the radical species formed at low temperature are the same as those used for dosimetry at room temperature, but with different concentrations. Their concentrations evolve as the temperature of the sample increases until the usual EPR signal used at room temperature is obtained. ► Alanine film dosimeters EPR response was studied at low irradiation temperatures. ► Changes in EPR signal with irradiation and measurement temperature were investigated. ► The temperature coefficient of the dosimeter obtained was 0.26%±0.02%. ► The EPR signal induced by irradiation is produced by two radical species. ► Radicals produced at low temperature irradiation are the same as those produced at room temperature but in different concentrations.