Behavior and size distribution of natural radioactive ions

The existence, qualitative constitution, and mobility distribution of short-lived decay products of radon in the form of positive small ions were investigated with a mobility analyzer. The activity was analyzed by α-spectroscopy. The decay curves of the activity corresponding to different critical mobilities were compared with the theoretical decay curves of short-lived decay products of radon. The small radioactive ions with critical mobilities about kc = 0.133 cm sq · sec-1 · volt-1 are carrying RaA:RaB:RaC in radioactive equilibrium, while ions with critical mobilities about kc = 3.98 cm sq · sec-1 · volt-1 are carrying presumably RaA. It seems that there is no strict limit between those two extreme cases.