The unified interaction model: Simulations of TL dose response and experimental verification of intended dose response linearity by postirradiation photon excitation

The Unified Interaction Model (UNIM) simulates the linear/supralinear dose response of the glow peaks of LiF:Mg,Ti (TLD-100) and other thermoluminescent materials and the dependence of the supralinearity on photon/electron energy. The UNIM is based on the radiation action of spatially correlated trapping centres (TCs) and luminescent centres (LCs), which results in localised (geminate) electron/hole recombination by quantum mechanical tunnelling. The linear dose response is mainly attributed to geminate recombination. UNIM simulations of the dose response of glow peak 5 in LiF:Mg,Ti following 500 and 8 keV electron/photon irradiation are discussed. In addition, simulations of postirradiation photo-excitation that redistribute the electrons and holes in the various TCs and LCs are demonstrated to extend the region of linear dose response and reduce the supralinearity. Experimental verification of dose-response linearity for levels of dose ≤ 30 Gy following both 3.65 and 5 eV photon excitation is presented. (authors)