Study of a deposition-based direct thoron progeny sensor (DTPS) technique for estimating equilibrium equivalent thoron concentration (EETC) in indoor environment

Inhalation exposures due to radon and thoron (222Rn and 220Rn): Do they differ in high and normal background radiation areas in India?

“…It measures time integrated 222 Rn, 220 Rn gas activity concentration. The detectors used for 222 Rn and 220 Rn progeny measurements were Direct Radon/Thoron progeny sensors (DRPS, DTPS) (Mishra et al, 2008(Mishra et al, , 2009a. These are energy degrader mounted SSNTDs, to selectively register the alpha particles emitted from the deposited progeny atoms on the surface of the detectors.…”

Outdoor thoron and progeny in a thorium rich area with old decommissioned mines and waste rock

“…Another and more reasonable explanation is that integrative TnP measurements are biased by a higher than assumed deposition velocity. Deposition velocity increases with increasing air velocity as well as with an increasing unattached fraction (Lai and Nazaroff, 2000;Mishra and Mayya, 2008;Porstend€ orfer, 1994), and outdoor conditions probably involve bias compared to indoor calibration. Whether this can explain the entire difference between the two measurement techniques is however uncertain.…”

“…Thoron equilibrium factors (F) therefore involve large uncertainties and measurements of thoron gas concentration are not suitable for dose assessment purposes (UNSCEAR, 2000(UNSCEAR, , 2006. Dose assessment should rather be based on direct measurements of TnP (Bangotra et al, 2015;Janik et al, 2013;Mayya et al, 2012;Mishra and Mayya, 2008).…”

Measurement of 220Rn/222Rn progeny deposition velocities on surfaces and their comparison with theoretical models

“…It is thus necessary to have a fresh look at these by developing accurate measurement methods and applying theoretical models to the data. To improve measurement reliability, it is more prudent to carry out long term, time integrated measurements of deposition velocity using passive track detectors (Mishra & Mayya, 2008). To apply theoretical models, it is necessary to measure as many environmental parameters as are possible along with deposition velocity.…”