In situ measurements of the sub-surface gamma dose from Chernobyl fallout

Methods of estimating external radiation exposure of soil-dwelling organisms are currently of much research and regulatory interest. In this paper, we report the first in situ measurements of the sub-surface gamma dose rate for ¹³⁷Cs contaminated land that quantify variation in dose rate with depth. Two contrasting sites have been investigated. The first site comprised a mineral type soil with a low percentage of organic matter and the second site chosen was in a peat-bog. The different soil compositions afford different ¹³⁷Cs mobility and this results in variations in the measured gamma dose-rate with soil depth. For each site the paper reports the measured dose rates, the ¹³⁷Cs activity depth profile, the ¹³⁷Cs inventory and a description of the soil-characteristics. It is suggested that these data can be used to produce estimates of the sub-surface gamma dose rate in other sites of ¹³⁷Cs contamination.