[ RadSafe ] Gamma background radiation at ground level

Ted de Castro tdc at xrayted.com
Wed Feb 23 15:35:36 CST 2011

On 2/23/2011 9:21 AM, McNaughton, Michael wrote:
> Filipe: background from terrestrial radiation is 5 to 15 microR/h, depending on the type of soil. Background from cosmic radiation is 5 to 10 microR/h depending on the altitude.  The supernova caused an increase of 0.5 microR/h at all locations so the increase was 2% to 5%. During a storm, gammas from Bi-214 and Pb-214 cause up to a factor of 2 increase, depending on the rate of the rain or snow fall.

AND - water saturation of the ground during a rain storm/rainy season 
LOWERS the background rate measured.  Data I took at a California site 
showed a short increase at the start of rainfall (washout) but a 
continued decrease as the rain continued, leveling off at saturation 
(shielding).  There was also a clear annual pattern - generally seeming 
to reflect ground moisture.

I was not able to detect supernova or solar x-ray bursts.

> Mike McNaughton
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Felipe Gaitan
> Sent: Wednesday, February 23, 2011 9:59 AM
> To: The International Radiation Protection (Health Physics) Mailing List
> Subject: Re: [ RadSafe ] Gamma background radiation at ground level
> Mike - What's the relative increase (%) in these two examples? Thanks, Felipe
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