| Reply #1
ullix
Germany
1171 Posts |
 Posted - 06/25/2017 : 00:31:46
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I got such significant discrepancies in count rates only with my light-sensitive tube. See the in-depth discussion here: http://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=4540
Follow that post to verify that your tube is NOT light-sensitive!
CPM=7000 is not lethal but also not negligible ( see calculation here http://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=4568) . Are you sure that your source could even give off such a high level of radiation? What kind is the source? Is it beta or gamma?
The tube itself adapts to a new radiation level within a millisecond or less, because that is how long a single pulse lasts. But in CPM mode the counter sums up all the events over the past minute, and hence it should adapt to a new rate level within exactly 1 minute. Compare with picture for a change from 550CPM to background. If it takes longer, then something else is going on.
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GMC-320 Plus high counting
