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Thread: Gamma Scout question

  1. #1 Gamma Scout question 
    New Member
    Join Date
    Jun 2011
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    Japan
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    Hi, I'm a Gamma Scout owner in Japan with a question for ppl familar with the device.

    My question is: how reliable is the geiger counter? The official figures in my area are much lower around 0.06~0.08 micro sievert per hour whereas the indoor readings on my GS show numbers up to 0.5 micro svt/hr sometimes during peak time.

    I've seen that readings are often vastly different from a counter to a counter; eg Inspector seems to show a little higher figure than others, GS included (because Inspector's the most sensitive??).

    It'd be greatly appreciated if someone familar with Gamma Scout could tell me just how reliable GS is, and if we should be afraid of the high readings and get out now. I understand that a scintillation counter would be more reliable but for now we do not have one.

    Thanks in advance,
    greentaco2


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  3. #2  
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    Join Date
    Aug 2011
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    Jusat saw your post. I got a GS2, and I seem to have the same problem: GS has consistently higher mcSv/h values than other device. A few indicators that it's the translation from CPM to mcSv/hr are
    a) i roughly get the same CPM as the folks at Safecast (around 40-50 CPM in central Tokyo). You can check this when you download the data to the computer. However Safecast translate CPM into mcSv/h using a factor of 350 (see First Safecast mobile recon Safecast and they continue to do so. My GS translates using a factor of 106, i.e. while my CPM readings are identical, the mcSv/h readings are higher by a factor of 3.
    b) GS do advise that around 106 is the correct factor. http://www.gamma-scout.com/Download/...GM_16mai11.xls
    c) Safecast advise that they use a more sensitive pancake probe, i.e. they would pick up more CPM... this does not sound right as I get similar CPM values to them with my less senstive GS2. The GS would have to report only 1/3 of counts if the pancake probe was that much more accurate.
    d) in northern Germany, the GS2 measured mcSv/h are 0.08-0.012, which is consistent with official figures there.

    Can we compare our figures? I would feel slightly better if I knew that at least between our two GS we would get similar readings, i.e. it's not miscalibration (which is unlikely given that they are supposed to be calibrated, and the test in Germany shows good figures)

    Thanks!


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