Thermoluminescence of X-ray irradiated KBr and KBr:Cu crystals

The thermoluminescence of X-ray irradiated KBr and KBr:Cu crystals has been studied in the temperature range 300-510 K. Four glow peaks with first order kinetics are observed at 359, 377, 392 and 409 K for a warming rate 40 K min-1. The trap depths for the above peaks are respectively 0.86, 0.97, 1.00 and 1.05 eV. The 377 K peak is related to the presence of Cu + ions in the crystal. Based on the identification of the filled traps with F-centres in different local environments, the thermal excitation energy of the F-centres to the relaxed excited state is deduced to be 1.7 eV for KBr ( and 2.0 eV for KCl).