Geiger counters, radiation detectors, lets see 'em

Brangdon

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On the side note, I consider the aspect of monitoring radiation an exercise in futility... even if you know its presence, what could you do?
Manage your exposure. Many of the dangerous materials also have short half-lives. After a nuke event, you can hope to shelter in place (if you can get plenty of mass between you and outside), and after a couple of weeks it could be safe to go out again. Depending on how bad the radiation levels are, you might want to limit your outdoors time to 10 minutes, an hour, or whatever.

(For example, Iodine-131 has a half-life of about 8 days. Tellurium 129 has a half-life of 6 days.)
 

OttaMattaPia

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I was thinking about getting the watch mentioned on here...just for 'kicks' so to speak (I collect watches anyway). But as some one mentioned above...these detectors in practice would be, em difficult to use to use to any real effect I guess. I work in radiation physics, and we have to calibrate our instruments twice a day (day/night shift), and you also need counting efficiencies for accuracy. You need different instruments, or probes for alpha...then beta/gamma, and neutron separate.

Just think people may get worried, as we get high readings, low reading from day to day...background varies a lot with location, and after it rains etc (radon). Dont get me wrong, they maybe good, and from my gadget loving side I would get one :p but by the time you would pick up meaningful radiation readings, you would probably already be in trouble. Unless you are near 'sources' quite a lot?

Saying that, some of our gear is...retro to say the least :)

Old thread....but I just got one of these (the new version) GCM-300E Plus V4
Pretty darn accurate little devices. I was able to determine the amount of radiation coming from my smoke detectors. One 50msv and one 62msv

Also, like someone else pointed out....you don't need exact, precise, scientific numbers.....just to know if there's an unusually high count. And you should put distance between you and that source.
Today, you have absolutely no idea what's in the truck next to you or where a source of radiation may be.

I like to throw it in a pocket and just carry it with me. It automatically alerts me if a preset level is reached. So far that hasn't happened but I do get occasional spikes.
I also check salmon and all seafood I get.

It was $100 delivered.
Another tool in the chest....like my L6 and other lights.
 

magellan

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Interesting thread.

We bought a Geiger counter a couple of years ago for the first time. Haven't seen it for a while, but if it turns up I'll post a photo.
 

TinderBox (UK)

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I considered getting one, But different radiation types require different detection tubes, so basically you want to detect the really deadly stuff, some radiation wont even penetrate your skin or clothing and the life of some radiation is very short.

I would check what type of meters Japan is using since Fukushima, though the general public might be getting sold the wrong type of meter, If this happened to China i would not buy any because of all the unscrupulous sellers, saving face over honesty.

John.
 

broadgage

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IMHO there is a lot to be said to possession of a Geiger counter, and preferably more than one.
More than one is desirable for a second opinion so as to avoid a false sense of security, or indeed a needless panic.

Most types are not terribly accurate, but that is not the idea, it is to give warning of levels significantly in excess of normal.

There is a lot that can be done if an abnormally high count is detected, even without any elaborate preps.
Firstly try and find out from media reports and your own observations if the problem is localised or regional.

If you sea or hear an explosion and the count rate trebles or worse, that suggests a terrorist attack or some form of fairly serious accident. Get someplace else URGENTLY. Even a few miles should help for a localised incident. In an urban area you might be able to simply take a bus or taxi away from danger if you act promptly before a few thousand others have the same idea.

For a regional event that can not be realistically escaped from, then shelter in place. Whilst construction standards vary a lot, as a VERY ROUGH GUIDE it may be said that being indoors in an inner room of a normal home reduces the dose to about one tenth of that received outside.
A domestic type of semi basement, or the inner parts of a modern office block reduce the dose to about one hundredth of that in the open.
A deep concrete basement of substantial construction, but NOT incorporating any specific radiation protective measures may reduce the dose to one thousandth of that received outside.
A purpose made shelter would give still better protection.

I have a couple of small and relatively cheap Geiger counters, "GEM RADALERT II" these are simple to use and give a simple bargraph display of coloured LEDs.
GREEN=NORMAL
YELLOW-PREPARE TO PANIC
RED=PANIC.

I purchased these new about 10? years ago. At the time these were issued to some members of the emergency services, and were selected for being simple and robust. The only control setting is a choice of averaging over 10 seconds, quicker if immediate danger is suspected, or 10 minutes which is much more accurate but you have to wait 10 minutes before getting a result.
These use a standard 9 volt battery and fit in a shirt pocket.
They detect the radiation from tritium lights if placed very close.

I also have a couple of larger and more sophisticated Geiger counters with a digital display, that can show dose rate per hour, or total dose per day/work shift, or simple number of counts. These operate silently OR with an audible "beep" for each count, and also have a programmable alarm that sounds when the dose rate or the total dose exceeds the programmed limit. These instruments require some knowledge of radiation physics to get best use. They also use standard 9 volt batteries and fit in a large coat or overall pocket.

http://www.perspectiveinstruments.co.uk/ These are ones that I have. The larger model is now discontinued.
 
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vadimax

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Always wanted to have something like that. Finally, the decision is made:



A US-made equivalent would cost me twice the price.
 

vadimax

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The Update: after watching multiple reviews I have changed my order to RadiaScan-701A:



It features more sensitive and fast sensor, counts alpha radiation, calculates surface radioactive pollution.

Negative moment: OLED screen is an overkill and consumes batteries.
 
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vadimax

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Damn, I better never knew that. Chinese "tritium" tubes contain krypton 85 (a byproduct of nuclear reactors) instead of tritium which is way more expensive. This way their radioactivity is 6 times higher over the natural radiation background:

https://youtu.be/mokuWl0ud1I

And, of course, even if they were with tritium, they are way overpriced.
 

mattheww50

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Tritium does NOT produce gamma radiation. Tritum Decays via Beta emission, which is simply an electron, and it is at very low energy (18kv), which is less then the energy of most of the electrons that were used in cathode ray tubes like TV sets. Most color television used something between 20 and 25Kv. Beta particles can ionize, so a Geiger counter can detect them. The problem is that at such a low energy, very few can get through the glass wall of the Geiger-Mueller tub to ionize. The mean free path of such a beta ray in air at sea level is literally a few centimeters. As a result of the very low energy emission, it can be used in a variety of applications very near living things (such as emergency exit signs in aircraft), with essentially no danger to any living thing. Essentially there is no radiation exposure because even a layer of dead cells on the surface of the skin is enough to stop almost all of the beta particles.
 

vadimax

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Tritium does NOT produce gamma radiation. Tritum Decays via Beta emission, which is simply an electron, and it is at very low energy (18kv), which is less then the energy of most of the electrons that were used in cathode ray tubes like TV sets. Most color television used something between 20 and 25Kv. Beta particles can ionize, so a Geiger counter can detect them. The problem is that at such a low energy, very few can get through the glass wall of the Geiger-Mueller tub to ionize. The mean free path of such a beta ray in air at sea level is literally a few centimeters. As a result of the very low energy emission, it can be used in a variety of applications very near living things (such as emergency exit signs in aircraft), with essentially no danger to any living thing. Essentially there is no radiation exposure because even a layer of dead cells on the surface of the skin is enough to stop almost all of the beta particles.

Perhaps, you have misunderstood my post. You are absolutely right when you are talking Tritium. The video was about Chinese "Tritium" tubes that contain not Tritium, but Krypton 85 which emits beta radiation of much higher energy (it penetrates the tube glass, the polymer body of a keychain light, and needs 7 layers of 0.11 mm aluminum foil to block it entirely.
 
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