Thermoluminescent response of lithium fluoride to high energy photons

Abstract

The thermoluminescent response per rad in water for 1*1*6 mm 7Li enriched lithium fluoride rods was measured for 60Co gamma -rays and X-ray beams of 35, 50 and 65 MV. A 10% decrease in sensitivity to the high energy X-ray beams was found when compared to the sensitivity to 60Co gamma -rays. No difference was observed between the sensitivities at 35, 50 and 65 MV. All measurements were made at approximately 400 rads which is within the linear part of the dose-response curve. The absolute dose in water was measured with a ferrous sulphate dosimetry system. Cavity theory calculations can be used to explain the decrease in sensitivity to the high energy X-ray beams as being due to a decrease in dose in lithium fluoride rather than due to a decrease in thermoluminescence. Calculated and measured sensitivities agree within the level of systematic errors.