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 2.GQ Geiger Muller Counter
 Test sources, negative ion generators, radioactive
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2 Posts

Posted - 09/20/2018 :  08:56:14  Show Profile  Reply with Quote
Hi, just picked up a GQ GMC300EPlus and I知 trying to make sure it痴 working properly. I知 getting somewhere between 15 and 35 CPM just walking around my house, but I want to see if I can make it spike. I have a bag of Brazil nuts that appear to do nothing. Tested my smoke detectors and the only thing it did was to set them off. I tried some supplements I have that have iodine and potassium (I know it痴 the wrong isotope I知 sure). Bananas do nothing.

Also I am interested in negative ions. I know that many of those trendy negative ion bracelets produce negative ions,.. but that would be because they are using radioactive materials in there production. Some of those bracelets produce as high as 2000 CPM. I obviously would not buy one of these, but I have a powered negative ion generator that I am concerned might be laced with radioactive materials. I have tested it with my GQ GMC300EPlus and it does not respond at all. This is why I want to make sure this type of Geiger counter is capable of detecting something of this nature.

Thank you

Signatures are a lie.
Reply #1


1255 Posts

Posted - 09/20/2018 :  16:52:29  Show Profile  Reply with Quote
All your source are very low radiation, you need to use Timed Count to compare with regular back ground level. Longer Timed Count period, the more differences you can see.

The smoke detector only has very little Gamma radiation.

Here is one of the picture showed how a smoke detector sensor used to test the unit:

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Reply #2


64 Posts

Posted - 09/20/2018 :  16:54:00  Show Profile  Reply with Quote
Common items to measure include:
- thorium lantern mantles (not all have thorium - measure in the store);
- a container of potassium salt; you need a good amount;
- uranium glass (vaseline glass) beads; easy to order from eastern Europe (I store mine in a lead lined container when not in use);
- Old Fiesta ware dishes.

Smoke detectors can be used with Alpha detectors, but the 300Eplus does not measure that type of radiation. Also the internal source shielding has to be destroyed first; it's designed not to leak radiation. Alpha emitting material is dangerous to handle (ingested particles can cause cancer).
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Reply #3


438 Posts

Posted - 09/21/2018 :  00:39:03  Show Profile  Reply with Quote
Your counter is behaving exactly as it should!

Smoke detectors with radioactive materials inside are not permitted in private homes in Germany, and only with restrictions in industrial settings. The typical smoke detector is based on an optical system completely without radioactivity.

Those which do contain radioactivity are mostly based on Am241, which is an alpha emitter. Its daughter nuclides as well. Only later down in the decay chain are also beta and gamma emitters.

With respect to household items and their radioactivity, you will find helpful information in these articles of mine taking advantage of Potassium's property to contain a radioactive isotop K40:
"GeigerLog-Potty Training for Your Geiger Counter-v1.0.pdf" for download here:

and in particular for measuring Potassium in bananas :
"GeigerLog-Going Banana-v1.0.pdf" from here:

Brazil nuts, potentially containing Ra, will also be mostly alpha radiation. Some decay products of it will have beta and also gamma radiation, but it will be at least as challenging to measure as the Potassium in bananas.

Learn about the Poisson distribution (also in above articles) to understand the statistical challenge. Good luck!
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Reply #4


2 Posts

Posted - 09/21/2018 :  09:24:24  Show Profile  Reply with Quote
Thanks everyone. I am guessing I need a pancake probe type of Geiger counter for looking at questionable ion generators. I will try using timed mode on my ion generators... but I知 not sure I知 going to trust the results. Correct me if I知 wrong, but this model is a Scintillation counter.

Signatures are a lie.
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Reply #5


438 Posts

Posted - 09/21/2018 :  23:45:42  Show Profile  Reply with Quote
What do you mean with "ion generators"? Those units sold for "air purification" in home appliances? I think this is basically a hoax. But let's look at the physics.

Which model is a scintillation counter? The 300E+ uses a Geiger-Mller tube; very different from a scintillation counter, which costs quite a bit more!

But the physics will apply to both.

Ion generators of the above type, may generate voltages up to several 10000 Volt. Thus the energies theoretically possible to achieve from such voltages are some 10000 eV (electron Volt) or some 0.01 MeV.

If these were beta particles, or even gamma particles, they would not be able to cross the wall of a Geiger-Mller tube (or the encasing of a scintillation counter). But these are ions, which would need far higher energies, like several Giga-electron-Volts to have the range in matter needed to traverse the tube wall. At best you find such energies at nuclear institutions like CERN near Geneva, in experiments done in big pipes in a tunnel at high vacuum!

Ions from these ion generators will have zero effect on a Geiger counter!

If you find an effect it could be from electrical interference of the ion generator with the electronics of the Geiger counter, but has nothing to do with radioactive effects.
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Reply #6


United Kingdom
334 Posts

Posted - 09/22/2018 :  11:23:02  Show Profile  Reply with Quote
Well explained, ullix. I also didn't know what obis was talking about in reference to ion generators.

About particle accelerators, for ions I prefer your facility in Darmstadt (near Frankfurt) called GSI/FAIR, which accelerates up to uranium ions and even create non-existing elements. CERN is "only" for high energy crazy physics, usually stopping at the atomic number of lead ;-)
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