Monitoring radon and its progeny in the environment of the vertical 15 UD Pelletron accelerator facility

Abstract

Environmental radioactivity due to radon and its progenies in the ambient air at the vertical 15 UD Pelletron accelerator facility of the Inter University Accelerator Centre, New Delhi, India was evaluated to calculate the annual effective dose to the workers and users. The radon activity was measured with an active monitor. The activity concentrations of the radon progenies were measured simultaneously using grab aerosol sampling and absolute beta counting. The effect of in situ meteorological parameters such as the temperature and relative humidity along the height of the Pelletron tower on the activity of radon and its progenies was studied. The measurements were carried out in the winter and rainy seasons. The values for the temperature, relative humidity (in percentage), radon activity concentration, radon Equilibrium Equivalent Concentration (EEC), annual exposure, annual inhalation and annual effective dose were recorded/calculated for locations with air conditioning and without air conditioning. Elements such as 218Po, 214Pb, 214Bi, radon and EEC activity concentrations were found to decrease with the height and relative humidity and increase with increasing temperatures. The dose levels observed in the facility were below the International Commission on Radiological Protection (ICRP) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommendations, even for the general public (1.2 mSv).