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SolarSurveyMonitor
Mexico
14 Posts |
 Posted - 05/19/2019 : 11:44:29
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I'm at sea level now, kinda desert environment but noticed weird readings. I got uncommon readings yesterday and was in doubt that the GM tube is photosensitive. On areas with solar light reflected I got readings about 60~110 CPM. Then I rotated counter for a moment to get tube lit with solar rays and started to click up to 500~600 CPM. (What a discovery!)
Today I just surveyed 28.86295373640999,-112.00699800256348 and got 40~50 CPM @ 1 m above ground. CSV log: https://drive.google.com/file/d/1yjV5gh4eg5y7ij-TTlHXnp_upi6pI043/view
A concern is if those readings are accurate, I'm guessing lots of beta radiation, or a hole in ozone layer, perhaps other things.
@ 12:42 GMT -7 indoors 38~49 CPM, 12:43 down to 12~23 CPM. |
Edited by - SolarSurveyMonitor on 05/19/2019 11:48:53
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| Reply #1
EmfDev
2250 Posts |
Posted - 05/20/2019 : 08:35:24
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| There are report before that some M4011 tube are sensitive to light. I think also if the voltage is too high, it can affect the reading. |
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| Reply #2
SolarSurveyMonitor
Mexico
14 Posts |
Posted - 05/22/2019 : 07:54:55
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| Ok, I looked around and I found posts about this issue. It's mostly sensitive to from early blue wavelenght to UV, like CFLs and bug killer lamps. On darkrooms doesn't seem to affect true readings. Testing with gas mantles has the same average ~750 CPM as I tested weeks ago. |
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| Reply #3
EmfDev
2250 Posts |
Posted - 05/22/2019 : 09:12:54
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| In a normal room with lights on are the readings the same compared to when you turned the lights off? |
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| Reply #4
SolarSurveyMonitor
Mexico
14 Posts |
Posted - 05/23/2019 : 22:21:12
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| Almost same. Because (device) average CPM varies about 1.3 CPM, I I'd like to test it further along some days with different types of light, CFLs, LED, incandescent, to collect sustained evidence. By the way, on GMC-300E+ 4.50, what's the time frame for calculating average CPM? |
Edited by - SolarSurveyMonitor on 05/23/2019 22:24:34 |
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| Reply #5
EmfDev
2250 Posts |
Posted - 05/24/2019 : 08:20:40
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Average CPM is the total counts (since you turned on the device) divided by the total number of seconds times 60.
Maybe try to use the Timed count feature and check total counts with in a time interval like 1 day instead of just the CPM. |
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Sensitivity of GMC-300E+
