Dosimetric Characteristics of LiF:Mg,Cu,P Phosphors - A Track Structure Interpretation

Abstract

Abstract New sintered LiF:Mg,Cu,P detectors with different concentrations of Cu and P are being investigated in this laboratory. These detectors are about 10-30 times more sensitive than LiF:Mg,Ti to gamma ray (60Co, 137Cs) doses and, unlike LiF:Mg,Ti, show no supralinearity up to saturation above 200 Gy of gamma rays, thus being amenable to a 1-hit interpretation, in terms of Katz's track structure theory. Values of model parameters, Eo=200 Gy and ao=20 nm, were estimated after fitting the 1-hit expression to a number of measured X ray and gamma ray dose responses and fitting to the reported measurements of relative efficiency of LiF:Mg,Cu,P after proton and alpha particle irradiations. The gamma ray dose response of LiF:Mg,Ti (e.g. peak 5 in TLD-700) can be described by a mixture of 1-hit and 2-hit expressions, but for model interpretations of exposures to low energy ions, only the 1-hit 'trap' (estimated values: Eo=600 Gy, a=20nm) need be considered. Thus, a quantitative model basis is provided for interpreting the response of LiF:Mg,Cu,P to heavy charged particles and neutrons against the responses of 'classic' LiF:Mg,Ti to the same radiations.