Further studies on higher temperature TL glow peaks of 7LiF:Mg,Ti

Abstract

Thermoluminescence (TL) characteristics of the higher temperature peaks of LiF:Mg,Ti, which exhibit a unique property of high relative response to high LET radiation, were studied in view of some recent findings and discussions. By making separate readouts of dosimetric peaks (mainly peak 5) and higher temperature peaks (mainly peak 7), the precision in TL measurements, reusability and, fading were found comparable for the TL readouts in the two regions. However, the intensity of higher temperature peaks was found to be susceptible to the annealing treatments. In the standard annealing treatment of LiF:Mg,Ti, namely, 400 °C for 1 h followed by 100 °C for 2 h, the intensity of the higher temperature glow peaks was significantly affected when the second step of lower temperature annealing treatment at 100 °C for 2 h was not used. The dose response function f( D) of higher temperature peaks to gamma rays in the range from 30 to 150 mGy was found to be within about 10% (−4 and +9%) but above 200 mGy it increased sharply. The intricacies of dosimetry of mixed fields of low and high LET radiation are discussed.