Sublinear response of peak 5 in LiF:Mg,Ti to low energy protons and carbon ions

Abstract

This work analyses experimentally and mathematically the heavy charged particle (HCP) thermoluminescence (TL) fluence response of sensitised LiF:Mg,Ti (TLD-100) peak 5 to 0.91, 2.95 and 4.32 MeV protons and 10.3 and 11.8 MeV carbon ions. Supralinearity was suppressed by sensitising the TLD-100 chips following a pre-exposure/annealing treatment. HCP irradiations took place using a Pelletron accelerator at fluences that ranged from about 6 × 108 to 3 × 1011 cm−2 and from 3 × 107 to 1 × 1011 cm−2 for protons and carbons, respectively. Results were compared to a Monte Carlo simulation of the Extended Track Interaction Model (ETIM) performed for each particle-energy combination. Experimental data show that the onset and behaviour of the HCP-TL fluence response function is weakly energy dependent for each ion type, in agreement with previously reported data of sensitised TLD-100 irradiated with low energy helium ions. ETIM fails to predict this behaviour showing instead a strong energy dependence of the simulated HCP-TL fluence response function.