| T O P I C R E V I E W |
| Kcp30228 |
Posted - 04/12/2023 : 14:11:43
Hello all! I purchased a GMC-500 sometime last October. I have had some autunite samples in a sealed vial for several years. It's about 2 or 3 g of flakes. When I 1st took a reading with my new Geiger counter it would read about 2000 counts per minute. As the months went by the count got lower and lower. I just thought it was the flakes "decaying"… Anyway, I also started noticing that my background atmospheric count went from about 30 counts per minute to eventually going to one count or even just 0. I sent my Geiger counter back and they replaced it. My background count registers around 20 counts per minute. My autunite flakes are registering around 300 counts per minute. Why would that sample go from 2000 CPM down to 300 in less than 6 months?
I'm very new to this hobby and I'm learning a lot. Should I expect that sample count to drop so rapidly? What would be the best way to check that my equipment is functioning properly? Would it be a good idea to purchase a verifiable check source such as cobalt 64 cesium 137 with laboratory certified numbers to check against a my device?
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| 4 L A T E S T R E P L I E S (Newest First) |
| Bobakman |
Posted - 05/07/2023 : 17:00:36
If you are looking for ore or rocks rather, I highly recommend this seller he has some of the oldest antiques that you could possibly own LOL!
Bob
https://www.bonanza.com/booths/Rockhound_Steve
And for a bit of flashback US history on an old American pastime watch this film.
https://youtu.be/fCdB1Wdc5VI |
| StevenL |
Posted - 04/28/2023 : 14:37:51
quote:
Originally posted by Kcp30228
quote:
Originally posted by ullix
If I am not mistaken then Autunite is an Uranium based mineral. If so, and your sample is not contaminated with any other radioactive substance, then we are talking Megayears of half-life. Meaning, you won't see a change in activity in your lifetime!
Can you post a photo of your sample, and how you position the counter for measurement?
Since you are new to this hobby I strongly recommend to not spend any money to purchase hot "certified" radiators! Once you got them, you would do what with them? Which result would tell you good or bad?
There are things in and around your house, which you can use to determine whether your sample is problematic or the counter defect. See my article "Potty Training" from:
https://sourceforge.net/projects/geigerlog/files/Articles/
I appreciate your feedback. Autunite is a uranium bearing source. I kind of played around with it a little bit more today. It's not like it's spitting out hundreds of curies of energetic particles. I should explain that I mostly paralyzed from an accident. I need help with all of this stuff. It turns out my nurse did not position the flakes/vial as close to my GM tube as when I 1st took a reading last October. I repositioned it today and the number is more or less where it should be. Yesterday it was a few inches from the device. Today it is sitting right on top of the device. Remarkable difference in detection numbers. Thank you for the link. I'll check it out this evening.
Hello Kcp, I am fairly new to this sector as well, doing lots of learning. Thanks for posting this info. Ullix is very helpful, and I have greatly benefited from reading Potty training, and I am now using Geigerlog.
My main goal at the moment is to properly characterize my background, and define the Poisson probability function so that I can integrate and calculate the probability that any given new reading is background or not.
Then I will start looking for local low rad sources, around the house. One day I may try to get some ores, but not for now.
Steven Lightfoot
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| Kcp30228 |
Posted - 04/13/2023 : 13:36:37
quote:
Originally posted by ullix
If I am not mistaken then Autunite is an Uranium based mineral. If so, and your sample is not contaminated with any other radioactive substance, then we are talking Megayears of half-life. Meaning, you won't see a change in activity in your lifetime!
Can you post a photo of your sample, and how you position the counter for measurement?
Since you are new to this hobby I strongly recommend to not spend any money to purchase hot "certified" radiators! Once you got them, you would do what with them? Which result would tell you good or bad?
There are things in and around your house, which you can use to determine whether your sample is problematic or the counter defect. See my article "Potty Training" from:
https://sourceforge.net/projects/geigerlog/files/Articles/
I appreciate your feedback. Autunite is a uranium bearing source. I kind of played around with it a little bit more today. It's not like it's spitting out hundreds of curies of energetic particles. I should explain that I mostly paralyzed from an accident. I need help with all of this stuff. It turns out my nurse did not position the flakes/vial as close to my GM tube as when I 1st took a reading last October. I repositioned it today and the number is more or less where it should be. Yesterday it was a few inches from the device. Today it is sitting right on top of the device. Remarkable difference in detection numbers. Thank you for the link. I'll check it out this evening.
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| ullix |
Posted - 04/13/2023 : 04:46:19
If I am not mistaken then Autunite is an Uranium based mineral. If so, and your sample is not contaminated with any other radioactive substance, then we are talking Megayears of half-life. Meaning, you won't see a change in activity in your lifetime!
Can you post a photo of your sample, and how you position the counter for measurement?
Since you are new to this hobby I strongly recommend to not spend any money to purchase hot "certified" radiators! Once you got them, you would do what with them? Which result would tell you good or bad?
There are things in and around your house, which you can use to determine whether your sample is problematic or the counter defect. See my article "Potty Training" from:
https://sourceforge.net/projects/geigerlog/files/Articles/
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