Effect of dose fractionation and dose rate dependence for some thermoluminescence dosimeters

Abstract

Nanomaterial (Ba0·88Sr0·12SO4)99.8%:Eu0.2% (B88n) thermoluminescence (TL) dosimeter exhibits promising characteristics for radiation dosimetry. In this work, the effect of dose fractionation and different dose rates were studied in such nanomaterial dosimeter comparing to the reference TL dosimeter (TLD-100). The effect of dose fractionation was studied at a reference dose of 12.7 mGy fractionated over 1, 2 and 3 weeks while the effect of different dose rates was investigated at 2.529, 5.457 and 419.4 mGy/h at the dose range from 0.21 to 1000 mGy. Results show that there is no significant difference due to the dose fractionation. Dose response curves at different dose rates were determined to evaluate the uncertainty due to dose rate effect. B88n dosimeter showed linear response at different dose rates. The small value of the uncertainty percentage owing to the variation of dose rates, 0.44%, indicates an insignificant effect of the dose rate variation. The result of fading at different dose rates over the course of 50 days revealed that there is a negligible fading, lies within the uncertainty of the TL/B88n measurements. By studying the effect of the dose rate of gamma radiation over four orders of magnitude, it has been found that B88n has less dependency than TLD-100. A computerized glow curve deconvolution (CGCD) of the glow curves of irradiated B88n to very low doses using general order kinetic GOK model shows six overlapped sub glow peaks. The 6th peak saturates at very low dose, lower than 0.2 mGy. The results from current study showed that B88n nanomaterial dosimeter has numerous advantages such as negligible fading, independence on both dose rates and dose fractionations, making it an excellent candidate for radiation dosimetry.