The re-estimation of absorbed doses of less than 1 rad measured with lithium fluoride thermoluminescent dosemeters

The technique of ultraviolet light bleaching for the re-estimation of the absorbed dose of radiation received by lithium fluoride thermoluminescence dosemeters has been extended to the extruded ribbon and PTFE disc form of dosemeter. The threshold of detection for the re-estimation of absorbed dose was found to be 1-1 rad for the PTFE disc dosemeters and 2-8 rad for the extruded ribbon dosemeters. A further study of this technique has revealed that by raising the temperature of the dosemeter during bleaching the threshold for re-estimated absorbed doses may be substantially reduced. The optimum temperature was found to be 80 degrees C and the practical threshold for the re-estimation of absorbed dose using a PTFE disc dosemeter was determined as 750 mrad.