Alpha and beta dose-rate determination using a gas proportional counter

Abstract

The use of proportional gas detectors for determination of the alpha (α) and beta (β) dose rate (due to U, Th and K) of pottery and sediment samples in luminescence and ESR dating was investigated. Alpha and beta count-rate measurements on standard powders of U, Th and K at two different counter voltages, low voltage in which the system detects α-particles only and high voltage in which the system can detect and distinguish between both α- and β-particles using different pulse height regions, allow the determination of conversion coefficients that relate count rates to dose rates in samples. The conversion coefficients were applied to the alpha and beta count rates measured on different types of test samples. Analysis of the results shows a remarkable accuracy in the evaluation of the beta dose rates. However, under both measurement conditions (low and high voltage), the alpha dose rates were found to deviate from the expected values to the extent that this procedure must be considered unusable at present.