| T O P I C R E V I E W |
| EmilyParker |
Posted - 08/25/2025 : 17:49:36
Hi everyone,
I’ve been using a GMC-600+ for about a year now, mostly for environmental checks, mineral samples, and some small sources. It’s been working fine so far, but I’m curious about the actual long-term durability of the Geiger Muller tube inside.
- Has anyone here used GMC-300/500/600 units continuously for several years?
- Do GM tubes tend to degrade noticeably over time or with the number of measurements?
- What are the first signs that a tube is wearing out—lower counts, noise, or obvious inaccuracy?
Would love to hear from anyone with real long-term experience (3–5 years or more).
Thanks in advance! |
| 2 L A T E S T R E P L I E S (Newest First) |
| Kaninbjerget |
Posted - 08/26/2025 : 08:46:09
Tube life is typically 1*10^9 for glass tubes or 1*10^10 counts for metal tubes - but look it up for your specific tube. Do the math. I believe I calculated lifetime for a J305/J321/M4011 with normal background radiation on my place if I remember correctly to be in the order of 60-70 years.
So if powered on just for background measurement I'll expect high voltage PSU to die first. But it's lifetime will be very dependent on design and component quality. Sometimes literally two cents in manufacture cost is gladly traded for many years less in lifetime (dependent on failure mode it might be able to be repaired rather easily).
How tube will degrade I'm not sure of though. Whether it'll decline slowly and at some level it's considered too worn or it'll remain more or less stable until the very end and decline rapidly.. Anybody knows? |
| Jadeye |
Posted - 08/26/2025 : 05:26:58
I have a GMC-500+, and I had it since the August of 2019, so for 6 years now. It is basically constantly running as a continuous monitoring station submitting data to the radiation map. I didn't experience any issues with the GM tubes inside of it (I had an issue with the Wi-Fi module which had to be desoldered and then replaced with the same type, which I did myself).
I never used it to measure sources with high beta or gamma radiation though, only those usually thorium isotope containing quack bracelets/medals, which are a bit above normal background radiation, and also tested some X-ray equipment a few times.
My experience may not help to answer your questions fully, but for me it seems these devices are quite durable, even the battery is still the original and working fine – and you can usually easily purchase replacement batteries and tubes if that becomes necessary. |
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