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wz
2 Posts |
 Posted - 08/15/2013 : 05:55:12
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Hello, I just recieved my new GMC 300 yesterday. The background readings here are averaging about 20 cpm.
I have an Aladdin mantle lamp, and the mantles are known to be radioactive, so that was the first thing I tested.
The lamp has a mantle but no chimney installed. Itis stored in a closed cabinet.
I opened the cabinet and held the '300 very close to the mantle,soon it was alarming, and after about a munite the reading peaked at 811 cpm, sorta alarming to me.
I then went around my place checking things in my shop and various stone and ceramics and read nothing other than background of around 20 cpm.
Went back about 1 hour later to the cabinet and the max reading of the mantle was 210 cpm.
This morning, still same background reading. I checked the mantle again for a munite or so and the leak reading was just 43 cpm.
Can you explain the different readings of the lamp mantle?
Thanks, Wayne
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| Reply #1
ZLM
1261 Posts |
Posted - 08/15/2013 : 08:07:46
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The distance and the position will affect the result.
The Geiger tube on GMC-300 is close to the lower keys. Try to place this part close to your source should get higher reading. |
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| Reply #2
wz
2 Posts |
Posted - 08/15/2013 : 15:30:06
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The distance and position were the same on all 3 tests, right up against the case directly behind the keys.
Could the turbulence of opening the doors have removed residual accumulated dust or gasses cause a variation of the lamp mantle's emittance?
Just checked the lamp again, 12 hours since last test, got a peak reading of 270 cpm. |
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| Reply #3
ZLM
1261 Posts |
Posted - 08/16/2013 : 17:25:34
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It is possible.
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3 diff. readings, same sample
