| T O P I C R E V I E W |
| Phildel |
Posted - 04/07/2023 : 15:58:18
I extracted and averaged 1min CPM counts from my GMC500 and plotted them Feb2019 to Mar2023 of Sunbury Australia.
The detector has never been re-calibrated and I was wondering if my 2019/20 upward drift was the device or was there a general increase in background CPM.
Interestingly Jan22 and Jan23 show a significant dip (summertime).
Any observations welcome and any idea where to get the device re-calibrated in Australia?
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| 2 L A T E S T R E P L I E S (Newest First) |
| igel |
Posted - 04/23/2023 : 01:37:47
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| GBG12 |
Posted - 04/10/2023 : 18:02:55
Some of the gamma logging sites in the USA run by their federal Environment Protection Agency (EPA) show a similar seasonal variation. It's hard to pin down a definite reason, but soil saturation makes sense. Surface radiation is a combination of sky source (what's left of solar and cosmic after being altered by the atmosphere) and ground-source (from rocks and Radon gas seeping up). Rain or snow can seasonally saturate the soils, blocking Radon seepage. Were Jan 2022 and Jan 2023 higher precipitation times in Sunbury? |
