Accurate calibration of a laboratory beta particle dose rate for dating purposes

This paper describes a novel method for calibration of the dose rate provided by a beta source used for luminescence dating. The calibration has been performed using an in-house calibration quartz that is given a dose in a Co-60 gamma ray facility. The gamma dose to the calibration quartz was calculated using Fricke dosimetry on simultaneously irradiated Fricke solution and Monte-Carlo simulations. An overall uncertainty in the dose to quartz of 0.6% (1 sigma) was achieved. The single aliquot regenerative dose (SAR) procedure was used to determine the irradiation time of the beta source needed to deliver the same dose to the sample. Results for a range of doses were combined by plotting irradiation time versus dose. A fit through the data points yielded the dose rate provided by the beta source at the sample position. This procedure resulted in an overall uncertainty in the beta dose rate of 0.9% (1 sigma). The beta dose rate was found to be in perfect agreement with an independent calibration using irradiated quartz provided by the Nordic Laboratory for Luminescence dating.