EFFECTS OF BLEACHING ON THE SENSITIVITY TO DOSE OF THE INFRARED-STIMULATED LUMINESCENCE OF POTASSIUM-RICH FELDSPARS FROM YNYSLAS, WALES

Reduction of the luminescence signal to a residual level before irradiation is an inherent part of the regeneration methods of equivalent dose (ED) determination, but is likely to lead to changes in the sensitivity of the dosimeter. Sensitivity changes caused by different methods of reduction of the infrared-stimulated luminescence (IRSL) signal have been investigated by subjecting potassium-rich feldspars extracted from modern dune sand from Ynyslas, on the Dyfi Estuary in Wales, to repeated cycles of removal of the luminescence signal and beta irradiation. The methods used to remove the signal were exposure to natural sunlight, a solar simulator and infrared-emitting diodes with a wavelength of 880 Delta 80 nm and heating to 450 degrees C.