RE: airfilters and radon daughters - Thoron vs. radon

["Marthaller, Chris" <Chris.Marthaller@wipp.ws>]

As I understand the situation, it is the particulate daughters that are of

concern in filter media.  The Rn decay chain from the Thorium series decay

has a much longer apparent half-life than the Rn decay chain from either the

Actinium or Uranium series decay.  All of the daughters must be taken into

account for decay purposes.  The different series decay is also the reasons

that to alpha to beta ratios can vary widely 

 



Chris A. Marthaller, RRPT 

Sr. Training Coordinator, WIPP 

(505) 234-8661 

Chris.Marthaller@wipp.ws 

I alone am to blame for my statements. 

"If we keep doing what we are doing, we will keep getting what we are

getting." ANON 





Thoron [Rn-220] has a half life of only 56  seconds vs. Rn-222 at 3.8 days.

Thoron airborne levels are accordingly usually quite negligible [often

thoron does not even escape to any degree from the soil, or thorium bearing

rock,  or building materials due to its very short half life vs. Rn-222] so

the thoron progeny in air would almost always be very low as well. 







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