Indoor and outdoor gamma dose rates were evaluated around a prospective uranium mining region –
Gogi, South India through (i) direct measurements using a GM based gamma dose survey meter,
(ii) integrated measurement days using CaSO4:Dy based thermo luminescent dosimeters (TLDs), and
(iii) analyses of 273 soil samples for 226Ra, 232Th, and 40K activity concentration using HPGe gamma
spectrometry. The geometric mean values of indoor and outdoor gamma dose rates were 104 nGy h1
and 97 nGy h1, respectively with an indoor to outdoor dose ratio of 1.09. The gamma dose rates and
activity concentrations of 226Ra, 232Th, and 40K varied significantly within a small area due to the highly
localized mineralization of the elements. Correlation study showed that the dose estimated from the soil
radioactivity is better correlated with that measured directly using the portable survey meter, when compared
to that obtained from TLDs. This study showed that in a region having localized mineralization
in situ measurements using dose survey meter provide better representative values of gamma dose rates.
2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND