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 1.Geiger Counter World Map(www.GMCmap.com)
 EPA Radnet data on GMCmap
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luminus

1 Posts

Posted - 06/11/2020 :  17:42:03  Show Profile  Reply with Quote
I was wondering if GQ would be interested in displaying EPA's Radnet data on GMCmap. I think it is doable but somewhat cumbersome. The data is publicly available at https://cdxnode64.epa.gov/radnet-public/query.do

I am not yet sure about the deployable stations, but the stationary stations have an RTS DDA-02 Dual Detector, which consists of an alpha/beta detector and a Gamma detector. The Alpha/Beta detector is a silicon detector. The gamma detector is a 2" x 2" Sodium Iodide crystal with a Hamamatsu R1306 photomultiplier. So the gamma detector is a scintillation counter, which means that the Radnet stations can sense almost every single gamma ray photon being emitted from radioactive particles trapped in its air filter.

I don't understand why there is no alpha/beta data on the EPA's website. So let's focus on the gamma-ray counts coming from the scintillator. Their scintillator has the following operational characteristics:

energy range: 70 keV to 2.5 MeV
sensitivity: 960 cpm/uR/h (count per minute to microRoentgen per hour) (960000 cpm/mR/h)
maximum working range: 5000 uR/h (5 mR/h)

That means that, with a background radiation of 0.025 mR/h, it will detect 24000 cpm, as opposed to a SBM-20, which will detect 33 cpm (22 cps/mR/h x 60 seconds per minute x 0.025 mR/h).

Since radnet data is more sensitive, it will need to be converted. Also, since count data is available per energy range, it will have to be added up. So, after adding it up, I suggest dividing the result by, say, 800 to get a count equivalent to the sensitivity of a geiger-counter.

Finally, take into account that each radnet station makes its count per minute data available every hour, but spread accross nine energy ranges, as mentioned earlier. By the way, the corresponding energy ranges per channel are:

2: 100-200 keV
3: 200-400 keV
4: 400-600 keV
5: 600-800 keV
6: 800-1000 keV
7: 1000-1400 keV
8: 1400-1800 keV
9: 1800-2200 keV
10: 2200-2800 keV

So, what do you think?

Reply #1

EmfDev

1438 Posts

Posted - 06/12/2020 :  08:41:47  Show Profile  Reply with Quote
Hi luminus, that is a good idea. We will discuss this and see if it is possible.
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