Development of a calibration facility for measurements of the thoron activity concentration

An extensive indoor 222Rn/220Rn monitoring in North-East India

“…The thoron concentration is highly inhomogeneous and is strongly dependent on the distance from the source (Nuccetelli and Bochicchio, 1998;Gargioni et al, 2003). It is poorly dependent on the ventilation rate because its decay constant (64 h −1 ) is much higher than normal ventilation rates (∼ 1 h −1 ), whereas the behaviour of the thoron daughter products, due to their longer half-lives, is similar to radon progeny.…”

Reference fields and calibration techniques for Rn-220 measuring instruments

“…The characterization of the 220 Rn atmosphere was performed using a multi-wire ionization chamber (MWIC) operating in pulse mode and is described elsewhere [9]. The uniformity of the 220 Rn reference fields was studied by measuring the 216 Po counts directly deposited on the surface of two Passivated-Implanted Planar Silicon (PIPS) detectors placed at several distances from the source, ranging from 1.5 to 44 cm.…”

“…In the past few years, a number of facilities for calibrating thoron measuring systems have been developed [5][6][7][8][9]. The basic set-up, common to all systems, consists of an airtight reference volume in which the thoron atmosphere is produced, a thoron source or thoron supply system, and several devices to monitor the thoron activity concentration and the environmental parameters.…”

Influence of environmental changes on integrating radon detectors: results of an intercomparison exercise

“…The monitor was calibrated at the Physikalisch-Technische Bundesanstalt (PTB) by comparing the reading with a calibrated ATMOS from the PTB. The measurement procedure and the calibration facility from PTB (6) . The uncertainty A. VARGAS and X. ORTEGA contribution from the reference instrument is $5% (PTB certificate) and a 5% contribution is added due to the calibration of the instrument used for measuring thoron concentrations in the chamber.…”