RE: Radon-222 and Radon-220 (thoron) Measurement and Action Level

["Redmond, Randy (RXQ) " <RXQ@Y12.doe.gov>]

	I want to thank everyone who provided me information on the

measurement of radon and thoron (and their daughters).  



	NCRP Report No. 97, chapter 8 has excellent information on the

measurement of individual radon daughters using gross alpha counting.  One

method is the "Tsivoglou."  The Tsivoglou method can be used to determine

the radon-222 alpha daughter concentrations - the formulas are listed in

NCRP Report No. 97.  The Tsivoglou was extended to include radon-220

(thoron) daughters; however, the two "extended" formulas are not included in

NCRP Report No. 97.  I have searched the WEB and cannot locate the two

additional formulas.  Anyone know a reference for these?



	Another question for the group (I'm looking for a quick and dirty

way to determine if I have a radon-220 issue).  

	-  Pull a sample on a filter (for example, Whatman-41, AW-19,

Fluoropore)

	-  If I "assume" the radon-220 and its daughters are in equilibrium,

and 

	-  allow the radon-222 daughters to decay, and

	-  gross alpha count the filter,

	will the Bi-212 activity (corrected for decay), pretty closely

approximate the radon-220 activity?



Randy Redmond

BWXT Y-12 L.L.C.

Y-12 National Security Complex

Radiological Control Organization

Email:  rxq@Y12.doe.gov

Phone:  865-574-5640

Fax:  865-574-0117







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