Measurements of radon flux and soil-gas radon concentration along the Main Central Thrust, Garhwal Himalaya, using SRM and RAD7 detectors

Radon in the Earth's crust or soil matrix is free to move only if its atoms find their way into pores or capillaries of the matrix. Rn-222 atoms from solid mineral grains get into air, filling pores through emanation process. Then Rn-222 enters into the atmosphere from air-filled pores by exhalation process. The estimation of radon flux from soil surface is an important parameter for determining the source term for radon concentration modeling. In the present investigation, radon fluxes and soil-gas radon concentration have been measured along and around the Main Central Thrust (MCT) in Uttarkashi district of Garhwal Himalaya, India, by using Scintillation Radon Monitor (SRM) and RAD7 devices, respectively. The soil radon gas concentration measured by RAD7 with soil probe at the constant depth was found to vary from 12 +/- 3 to 2330 +/- 48 Bq center dot m(-3) with geometrical mean value of 302 +/- 84 Bq center dot m(-3). Th significance of this work is its usefulness from radiation protection point of view.