A new reference block for field gamma spectrometry applications in ESR and luminescence dating

Abstract

A new granite-doped concrete block with 60 cm x 60 cm x 60 cm dimensions has been built at CENIEH, Burgos, Spain, for dosimetry calibration and cross-referencing purposes. Independent evaluations of the block’s gamma dose rate using passive Al2O3:C dosimeters and various field gamma spectrometer (NaI) probes produce consistent results of 1495 ± 51 μGy a-1 and 1514 ± 43 μGy a-1 (or 1537 ± 19 μGy a-1, depending on the evaluation procedure employed), respectively. Bulk radioelement concentrations calculated from field gamma spectrometry using the Windows method are as follows: K = 1.58 ± 0.08 %, U = 4.26 ± 0.28 ppm, and Th = 12.62 ± 0.72 ppm. This new block complements existing dosimetry reference materials accessible at other laboratories and is available for the broader trapped charge dating community to use for instrument calibration, reproducibility assessments and intercomparison studies.