The kinetics of TL peaks and its effect on the dose versus temperature plot

THE THERMOLUMINESCENCE (TL) DOSE RESPONSE OF COMPOSITE PEAK 5 IN LIF:MG,TI (TLD-100): DEPENDENCE ON THE ORDER OF KINETICS

A seeming contradiction in the prediction of the spatially correlated trapping center/luminescent center model applied to LiF:Mg,Ti has been the linear/supralinear behavior of the dose response of glow peak 5a. In the TC/LC model, the localised electron-hole recombination, giving rise to glow peak 5a, is expected to result in an extended region of linear dose response. Deconvolution of the glow curves based on first order kinetic peak shapes results, however, in a dose response of peak 5a, which closely resembles the linear/supralinear dose response of peak 5. It is demonstrated herein that when general-order kinetics peak shapes are used for peak 5a, the analysis can result in a linear dose response of glow peak 5a up to dose levels as high as 30 Gy, well beyond the 1-Gy onset of supralinearity of peak 5. The extended linearity suggests a resolution of the contradiction.

EPR dosimetry with tooth enamel: A review

When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed.