Converting Measured Exposure/Dose Rates to Effective Dose Equivalent

["Leo M. Lowe" <llowe@senes.ca>]

It is often necessary to convert measured exposure  rates to effective dose 

equivalent for comparison to regulatory limits.  For example,  an exposure 

rate of 1 microroentgen/h (uR/h) due to U-238 series radionuclides in the 

ground equates to an effective dose equivalent rate for adults of about 0.6 

urem/h (0.006 uSv/h).  The conversion is approximately the same (within a 

few percent) for the natural Th-232 series.



My question relates to converting measurements, made with tissue equivalent 

survey meters, to effective dose equivalent.  The response of such meters 

is purportedly based on the deep dose equivalent from a uniparallel 

direction beam.  For the specific case of measurements above a large planar 

source containing natural uranium (or natural thorium), does anyone have 

any information on  the conversion between the measured dose rate (reported 

in uSv/h) and the effective dose equivalent (in uSv/h)?



I get Radsafe in digest mode.  Please feel free to respond directly to me.



Thanks,

Leo M. Lowe, Ph.D., P.Phys.



SENES Consultants Limited

llowe@senes.ca

www.senes.ca

Tel: (905) 764-9380

Fax:(905) 764-9386



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