Thermoluminescent dosimetry of high-let radiations and its application in radiation protection

The application of the so-called track structure theory (the Katz model) to the description of high-LET dosimetry using the TLD-700 (7LiF; Mg,Ti) thermoluminescent dosimeters is described. To explain the supralinearity in the response of this dosimeter to low-LET radiations (X or γ-rays) the pre-existence of so-called 1-hit and 2-hit trap structures is assumed, their respective signals are increasing linearly or quadratically with dose. In general, a c-hit detector is characterized in track structure theory by 3 phenomenological parameters, two of which (characteristic dose and ''hittedness'') fully specify the low-LET response of the dosimeter, and addition of the third parameter (radius of sensitive site) enables one to calculate the response of the dosimeter to any high-LET radiation (heavy charged particles, heavy ions, etc.). It follows from the theory that detectors supralinear in their response to low-LET radiation may show an efficiency exceeding 1 for identical doses of high-LET radiations, which is seen experimentally in LiF. A review of c-hit detector theory is given, followed by results of calculations which show that the predictions of the nodel agree with most of the experimental data for lithium fluoride. The concept of ''rem-equivalent'' dosimetry is introduced, i.e. the development of a thermoluminescent dosimeter the signal of which could directly correspond to the degree of damage in a given biological material following its irradiation. (author)