Direct excitation of high temperature thermoluminescence (HTTL) in quartz by low temperature X-irradiation

It is generally accepted that the high temperature thermoluminescence (HTTL ) in quartz in the temperature range 450-700 K cannot be excited by irradia tion below about 200 K. Still some crystals in our laboratory were excitabl e at low temperatures. This effect is shown to be produced by irradiations in the history of the crystal at temperatures mainly in the range 300-400 K . These irradiations were found to produce deep electron traps (DETs) stabl e above 750 K. Irradiation in the range 300-400 K was found to produce the DETs and to fill up only part of them by electrons. The latter are conseque ntly emitted as HTTL. The remaining empty DETs can then trap electrons even by low-temperature irradiations. Under suitable repeated irradiations the concentration of the empty DETs rises and with it grows the intensity of th e low temperature excited HTTL. Some characteristics of the DETs and their filling and emptying by irradiation are described and discussed. The model offered for the HTTL was found to be usable in explaining unsolved problems related to the HTTL. (C) 3000 Elsevier Science B.V. All rights reserved.