Geiger Counters & Dosimeters

[Omega]

Thanks a lot, Appin. I am looking at FNIRSI GC-01 Geiger Counter and Dose Monitor because it is quite cheap. Do you know if they are reliable and work well? I don't mind replacing it in 5-6 years, but this is something different from what I knew long time ago

[steptoe]

Sorry just jumping in here as far as i know you need to understand the machine and know what your looking at to understand it a bit like radar ops it takes years to learn you do not just pick it up and go oh look it is safe like in the movies .
The reason i say is i had to have many scans and some very weird stuff pumped in to my body and one guy came in in full hazmat suit with a lead gown over and holding a small case at arms length he opened it and loaded it in a syrigne type thing and i kid you not the thing was giving off a light glow like a night fishing float lol after the op i get told do not go near children or near pregnant women for 7 to 14 days .

I was told then that it was high doseages of radioactive liquid and that doing it was high risk as the amount of scans as well , i think andy might know something on geigers i am sure but again if your thinking in the event of ww3 you can grab it and run round going safe zone not safe i don't think it works like that , i could be wrong but don't throw money at something if you do not know how or why you need it .

It is people getting scared now with all the chat online and on the you tube channels people are panicing , if ww3 happens and i can not see how it will not i doubt it would go to nukes because if it does we are all going to kiss our backsides good bye .

[Appin]

You do need some understanding but a working knowledge of the basics would probably see you right.

Having the ability to make basic measurements of radiation would allow you to take cover without waiting for official channels to decide they had better do something.

It is worth keeping in mind that both the UKWMO ( YK warning and monitoring organisation) and the ROC(Royal Observer Corps) were stood down over 30 years ago.

There is no formal siren network. There are “arrangements “ with broadcasters. A mobile phone network based system using what is called Cell Broadcast is due to come into use imminently. Concerns about cell networks reliability during power cuts are widely known.

I have some formal training on geiger counters etc. If people want I could write guide covering the basics?

[Appin]

I have taken a look at the FNIRSI GC-01 Geiger counter.
A few random thoughts.

Manufactured in China so any guarantee is probably worthless and I would not trust the calibration.

The measured dose range quoted is odd. Some reviews suggest the GM tube is poor quality. If so tube life may be poor.

Also keep in mind geiger tubes are not ideal for measuring doses if used they need to be energy compensated. More modern dosimeters use solid state detectors.

At a basic level it can give counts per minute and that is useful. Anything that is going to measure doses accurately is going to cost.

[Arzosah]

I do find this interesting, but I'm not in the market for buying right now. I had a look round, even so. And .... https://www.anythingradioactive.com/nuc ... guy-figure Look at his little face what a great find!

I'll get my coat, but I really loved it!

[tarmactatt]

I've a couple of Geiger counters mostly for scientific interest rather than prepping.

Some thoughts:

1) Generally, you get what you pay for.

2) Decide what you want to measure- alpha needs a mica window tube. Most of the SBM-20 tubes do gamma and some "stronger" beta.

3) The idea of detecting "contamination" in food and water is generally overrated, unless you've SERIOUS contamination, a regular GM counter won't detect it. You'd need a lead lined gamma spectroscopy set up (£££££).

4) Generally the dose/dose rate value on the screen of these counters is calibrated to specific isotopes, as the energy emitted is different for each one. Don't get hung up on dose, look at the Counts Per Minute reading, if you know what your background normally is, you'll get a good idea of whats irregular. More clicks = more radiation.

Suggestions:

eBay DIY kits- I think shipped from a guy in Israel, I've one with an SBT-11A mica window tube and it's good fun. Most common builds use the rugged SBM-20 tube. It does involve minor assembly and you'll have to make/3D print/source a case. The mica window is fragile.

I've also a DIY kit that runs a big SBM-19 tube, makes more clicks than the smaller SBM-20 tubes, which is more satisfying when detecting small levels of radiation in eg. Granite worktops.

The GQ GMC-500+(?) type counters were some of the most popular early Chinese Geiger counters, I don't have any experience with them but they look okay, if a tad expensive for what they are.

The FNIRSI counters are pretty cheap, again no first hand experience, they look okay though.

The Bosean FS5000 is my most recent addition to the "collection". Build quality is okay, bit plasticy, the software is usable. I've seen a site somewhere where someone is programming custom software, it doesn't look straightforward but when the software is ready i might spend time to try and download and upgrade the software.

Used Series 900 Mini Monitor, these used to be very good value for money on eBay but now go for high prices. Prices vary on condition, meter face and included probe. Gold standard for gamma (+some beta) would be a scintillation probe, but these are expensive.

Radiacode devices are different to Geiger counters, they are more expensive but seem pretty popular on Reddit etc.

Hope the above helps!

[GillyBee]

I think it all boils down to what benefit you think you might get from having a Geiger Counter. I was working at Philips in the eighties and got to DIY an early handheld one just after Chernobyl. The only thing I could really use it for was to wave over the lamb in Sainsburys which was a cuase of tabloid concern.
So one might help if foraging in a post nuclear apocalypse to select less contaminated food/drink - but you would need to be able to test for the different types of radiation and they need different machines to test.
Or you may decide that if it is that bad you should just get out of Dodge as fast as you can using our "safer" preps and not worry about carrying around a GM counter.

[GeraldTheBonzai]

I have a GQ GMC500+. Have also used higher end, more professional kit in the past. It's ok as something to have in the house but I wouldn't rely on it for anything serious.

Mine can connect to the internet and publish data to www.gmcmap.com. Lets me compare my background CPM to other devices in the local area plus europe etc. So if there was a Chernobyl type incident, I could probably see it ( not that I could do anything about it other than take precautions). It also has a dosimeter built in.

These devices can be fiddly to set up - you have to get the tube voltages just right. I had a lot of issues when I first got it with silly CPM until I did some research and made adjustments. So it's good for an order of magnitude type reading.

On an aside, if you want to check that it's working, you can pick up thorium gas mantles for a few £ off of ebay. These are mildly radioactive (beta) so you can use it as a test source.