Radon migration from subsurface soil to atmosphere using Crank Nicholson differencing scheme

Radon is a radioactive noble gas produced in the naturally occurring decay series namely thorium series, actinium series and uranium series. While the decay of ²³²Th produces isotope ²²⁰Rn with half life of 55.6 sec, ²³⁵U decay produces radioisotope ²¹⁹Rn with half life of 3.96 sec and ²³⁸U decay produces ²²⁶Ra which produces ²²²Rn with half life of 3.82 days. ²²²Rn is relatively long lived and hence is a major health hazard among all sources of radiation. Proper estimation of ²²²Rn concentration in inhabited regions is therefore essential for dose estimation due to inhalation. The source of this radon isotope is decay of ²²⁶Ra produced in the ²³⁸U decay series which is present in most of the soil types