Evolution of Analytical Methods for Radon Measurement in India

This paper discusses the different methods and instruments followed in India for the estimation of 222 Rn, 220 Rn, 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.