The use of calcium silicate bricks for retrospective dosimetry

Abstract

The suitability of calcium silicate bricks (CSBs) for the retrospective measurement of gamma dose using luminescence techniques has been investigated. Bricks of this type are distinguished from fired clay bricks by containing negligible clay and requiring comparatively low temperature treatment during manufacture. They have been used widely in the construction of buildings in the Former Soviet Union since the 1970s but hitherto have not been used for retrospective dosimetry measurements. A procedure based on the use of the 210°C thermoluminescence (TL) peak of quartz was tested with granular quartz extracted from three types of CSB, one of which had been taken from a settlement downwind of Chernobyl. The degree to which the residual geological TL signal within the temperature range of the 210°C TL peak had been reduced during manufacture varied with brick type; the levels of residual TL corresponded, in the samples tested, to absorbed doses in the range (<5 mGy–100 mGy). The TL sensitivity of the quartz was generally sufficient to measure absorbed doses of 20 mGy and above. An estimate of the cumulative fallout dose obtained with the CSB from the contaminated settlement was in good agreement with that obtained in a previous study based on measurements with a fired clay brick from the same building.