[ RadSafe ] Determining Radon

[John Andrews]

cobdw at tds.net wrote:

>Our soil remediation project just acquired a PCM-2.  This is a whole body gas proportional frisker set up to detect alpha and beta contamination.  Since we are a soil remediation project, we are subject to radon gas. Per our procedures, we are required to report all personal skin and clothing contaminations with the exception of contamination due to radon gas.  I was wondering if anyone out there has had experience with this type of instrument in detecting radon gas and what methodology is used in the field to determine if the alarms are due to radon or real contamination?  Please keep in mind that we do not have a count room available with the gamma spec. capabilities.  We are limited to field instruments only.  
>
>Thank you in advance for all replies to this inquiry.
>
>Douglas Coble
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Contamination from radon is primarily alpha activity from the 
daughters.  These daughters have a half life of about 30 minutes.  The 
appropriate action on contamination is to detain the person for about 
one half life and recount.  If the activity drops by about half, then 
the proximate source is radon gas.  Some history of these readings 
should be maintained and used to document subsequent actions or changed 
protocols.

A gamma-ray spectrometer system would be really helpful in analyzing for 
radon daughters on air samples in the area where some contamination is 
suspected.

Don't feel alone in this process.  It is an ongoing problem for many 
operations.

John Andrews, Knoxville, Tennessee