Evolution of Analytical Methods for Radon Measurement in India

This paper discusses the different methods and instruments followed in India for the estimation of ²²²Rn, ²²⁰Rn, and their progeny. Radon concentration is either directly measured from radon alpha or its progeny alpha emissions. The duration of sampling, necessary information and specific application influence the selection of a particular monitor. In India, we use indigenously developed instruments like scintillation cells, LLRDs, electrostatic collection instruments, electret ion chamber, pulse ionization chamber-based Alpha Guard, electrostatic collection of Radon progeny atoms by RAD7 and Radon Scout Plus for the measurement of these carcinogenic gases. Scintillation cell-based measurement is found to be most reliable for the mine environment whereas highly sensitive instruments like ionization chamber and silicon detector are preferred for continuous radon tracking. Solid-state nuclear track detectors have also been used for long-term radon estimation covering the diurnal and seasonal variations.