Dielectric changes and thermoluminescence of sodium chloride and lithium fluoride irradiated with X-rays

Abstract

The dielectric changes exhibited by sodium chloride and lithium fluoride on heating after X-ray irradiation have been measured at a frequency of 500 Kc/sec. The thermoluminescence has also been recorded. It is observed that the dielectric loss of both the samples increases during thermal bleaching. The difference between the dielectric losses of the crystals before and after colouration i.e.Δ tan δ, for different stages of thermal bleaching is found to show steps, the temperature regions of which agree with the temperatures of the glow peaks. It is presumed that this observed excess dielectric loss is due to the large number of vacancies created by the destruction of colour centres at the corresponding glow peak temperatures.