An investigation of field fading in LiF (TLD-700) in an environmental monitoring programme

An examination of the maximum amount of fading in LiF (TLD-700) in relation to the ambient temperature under actual environmental conditions is described. In an environmental radiation monitoring programme extending for seven consecutive approximately two-month periods, pre-exposed thermoluminescence dosemeters (TLD's) were packaged with those that were initially blank. At the end of a given monitoring period, a recovered value for the pre-exposure was obtained, and the fading determined. In the worst case, the fading was no greater than 7.0%. That the fading tracks the ambient temperature is both illustrated and discussed; its implications are noted and recommendations for minimising it are offered. In addition, the results are shown to exhibit good agreement with trends predicted by the theory of Randall and Wilkins. (author)