Monitoring environmental dose rate using Risoe TL/OSL readers with built-in sources: recommendations for users

Measurements were carried out to quantify the dose rate delivered to samples due to leakage and cross-talk of the beta and alpha sources in various models of Risoe TL/OSL readers; additionally the offset time was calculated. Highly sensitive [alpha]-Al sub(2)O sub(3):C and CaF sub(2):Mn dosemeters were used to investigate the impact on low environmental dose-rate assessment. The effect is shown to depend on the energy response of the detectors, the source strength and the reader design of the equipment. It was tested, if the scattered radiation of the closed source can be utilised to extend the dose range downwards to lower doses, as the dose rates of the built-in sources of Risoe TL/OSL readers often exceed the practical values for ultra-low-dose measurements. The results and their consequences for environmental dose-rate assessment are discussed.