[ RadSafe ] Infinite Thickness of KCl

[Dixon, John E. (CDC/ONDIEH/NCEH)]

Erik,

This could be a candidate case for MicroShield. You could set the photon energy for K-40 and alter the source thickness manually and then run the program. This would take several iterations. For this case, I would not use the transmission factor relationship since you are searching for the thickness of source material which is going to emit gammas no matter what the thickness. You just need to find the thickness where the fluence appears not to change.

John Dixon

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Nielsen.Erik at epamail.epa.gov
Sent: Tuesday, August 30, 2011 12:50 PM
To: radsafe at health.phys.iit.edu
Cc: liste de distribution pour les RADIOCHIMISTEs
Subject: [ RadSafe ] Infinite Thickness of KCl

I am trying to determine the infinite thickness of the 1460 keV gamma 
emission (10.5% abundance) of a planar source of KCl (416 pCi/g) and a 
density of 1.98 g/cc.

In other words, what is the thickness of a KCl planar source where any 
additional thickness does not increase the surface dose rate?

I have scoured my references but have not located the appropriate formula 
for calculating this value.

I would appreciate any references or suggestions for an appropriate 
calculation.

Erik C. Nielsen
USEPA, National Air and Radiation Environmental Laboratory
540 South Morris Ave.
Montgomery, AL 36115
Phone 334-270-3475
Fax 334-270-3454

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