Advanced trap spectroscopy using the glow rate technique based on bleaching of color centers

The glow rate technique (GRT) is the extension of the known heating rate me thod to the full glow curve. The GRT Re the fractional glow technique (FGT) offers a procedure for evaluation of the mean activation energy as a funct ion of temperature in the case of arbitrary thermostimulated relaxation kin etics represented by trap distribution function. The experimental procedure involves at least two subsequent measurements of thermostimulated recombin ation kinetics at different heating rates. The extension of the GRT to the direct measurements of thermostimulated bleaching of the radiation-induced color centers is presented. The experimental procedure involves measurements of the decay of radiation- induced absorption spectra of color centers in preliminary irradiated mater ials during linear heating. Procedure for evaluation of the trap energy and frequency factor spectrum is considered in the paper. Results of the application of GRT for analysis of the parameters of thermos timulated decay of color centers are presented in the case of decay of the radiation-induced defects in LiBaF3 crystals irradiated by X-rays. It is sh own that decay of F-type centers occurs in two steps, the activation energy slightly decreasing from 0.660 +/- 0.003 eV in the first step (300-370 K) to 0.615 +/- 0.003 eV (400-480 K) in the second step. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.