[ RadSafe ] Gamma background radiation at ground level

[McNaughton, Michael]

I agree with Ted. During the spring, we see a gradual increase in terrestrial radiation as the snow melts. We can even measure the thickness of the snow.

(By the way, on rare occasions we also detect radiation from LANL, amounting to less than 1% of the background radiation.)

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Ted de Castro
Sent: Wednesday, February 23, 2011 2:36 PM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Gamma background radiation at ground level



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.