Variation with depth of dose distributions in single grains of quartz extracted from an irradiated concrete block

Most attempts to apply retrospective dosimetry using luminescence methods to building materials have made use of heated (sensitised) items such as brick or tile ceramic. Unfired materials, such as mortar and concrete, are much more widespread in the industrial environment, but unfortunately these cannot be assumed to contain a negligible dose at the time of construction. We have analysed the dose distributions derived from optically stimulated luminescence (OSL) measurements of single grains of quartz extracted from two industrially produced concrete blocks, one unirradiated and the other irradiated normal to one face in the laboratory using Cs-137 gamma photons. The OSL dose-depth profile for the irradiated block was determined by measuring the dose distributions from single quartz grains extracted from slices taken across the block and compared with that predicted using Monte Carlo calculations. Despite measured doses in grains extracted from the unirradiated concrete of up to 140 Gy, we show that it is possible to detect accrued doses of about 100 mGy from grains extracted from the bulk concrete, and about 50 mGy in grains extracted from the surface of the block. (C) 2003 Elsevier Ltd. All rights reserved.