This device allows for acquisition of alpha particle energy spectra, in order to distinguish alpha particles originating from radon and radon progeny decays, as well as those originating from thoron and its progeny decays.
The increase in dose rate at a given time is a function of the amount of progeny decaying, which in turn is a balance between deposition of progeny by rainfall and radioactive decay.
Once in the lung tissue, deposited radon progeny decays to generate alpha-particles, which damage DNA both directly and through generation of free radicals [ 51].
But the progeny of the decay may include lighter supersymmetric particles that cannot disintegrate any further, and are called, with uncharacteristic lack of luster, L.S.P.'s, for "lightest supersymmetric particles".
We included decay of progeny by using weighted averaged rainfall intensity, where the weight decreases back in time.
Moreover, given the very short half-lives of many of the progeny of the 238U decay series (such as 214Pb and 214Bi) it is reasonable to assume that such species may be present, however fleetingly, at some point between production and consumption of an STP.
The second group comprises the decay products or progeny of the primordial elements, which are collected into radionuclide groups known as decay series, including the 238U series, 232Th series and actinium series of radionuclides.
The radionuclides 134Cs (τ = 2 years) and 131I (τ = 8 days) would be expected to have decayed to their progeny in the time scale between recent nuclear reactor incidents (e.g. Chernobyl in 1986) and the date of this study (2008 2010).
Thoron has a half-life of 55 sec, but radon has a half-life of 4 days; therefore, the very short half-life of thoron prevents it from diffusing very far before it decays to thoron progeny.
The absorbed dose calculation included the decay of 227Th and its progeny 223Ra, 219Rn, 215Po, 211Pb, 211Bi, and 207Tl for an initial activity of 1 MBq and an integration period of 1920 h.
