geiger counters

[Ross]

This isn't in freedom and self reliance for a reason My boy (and future geologist) has inherited a rock and mineral sample collection from my Uncle who was a geologist who passed away several years ago. Unfortunately my Aunt is not a geologist and to be frank there are lots (hundreds of pounds of samples) that could contain radioactive minerals. I don't want to assume they're all safe I know he has at least one sample of uraninite, and my boy will find school uses for the detector I'm looking at. Trouble is I don't know a decent detector from Hoover vacuum cleaner. Anyone know if this will do what we'll need? Fortuantely I do have access to family who should know this stuff too, but the mroe info I have the better choice I'll make!
eBay link

Poratabliity is a non issue the boy has a better laptop than most of us homesteaders will ever see.

[Explorer]

A Geiger counter detects the presence of radioactive material, it is not a highly accurate instrument. (The detection is on a relative scale.)
Just about any one will serve the purpose of detection for surface samples. There should still be surplus counters (cheap) still available as they were plentiful in the 60's.

The amount of radioactivity in any naturally occurring surface sample is very small. Wash hands after handling or wear rubber gloves, absolutely do not let him grind the samples without breathing protection. A local university should have a counter and maybe a student who can come over to help you.

[ace admirer]

if you want to purchase try this www.sciplus.com otherwise i would try local high school lab, community college to gain access to one.

[antiquestuff]

Originally Posted by Ross

This isn't in freedom and self reliance for a reason My boy (and future geologist) has inherited a rock and mineral sample collection from my Uncle who was a geologist who passed away several years ago. Unfortunately my Aunt is not a geologist and to be frank there are lots (hundreds of pounds of samples) that could contain radioactive minerals. I don't want to assume they're all safe I know he has at least one sample of uraninite, and my boy will find school uses for the detector I'm looking at. Trouble is I don't know a decent detector from Hoover vacuum cleaner. Anyone know if this will do what we'll need? Fortuantely I do have access to family who should know this stuff too, but the mroe info I have the better choice I'll make!
eBay link

Poratabliity is a non issue the boy has a better laptop than most of us homesteaders will ever see.

That thing is very expensive for your purpose. Just search "geiger counter". Search for US auctions too. Old Civil Defense geiger counters are pretty cheap. Just see that it works: ask questions about it.

If you're worried about a dose of radiation you're getting, find a dosimeter (you'll need it and the charger). they're cheap too.

[wr]

Ross, I know there are a couple industrial radiography companies in your area. The equipment they use is way better than the average guy on the street can afford but they also upgrade every couple years and the older equipment lays in a box in the back room. Your son would likely want two pieces from them, he'd want what the industry calls a rad-tad which is the little box that beeps in increasing loudness and frequency the closer he comes to radiation and likely a dosimeter which is like a tiny telescope that shows how much radiation is being emitted. I would recomend hitting the phone book and looking under industrial radiography or non destructive testing to find the appropriate companies and I'm betting you'll get what you want cheap or free. I used to work in the industry but haven't for years and it's been 25 years since I worked with any companies down your way so nothing is coming to mind at the moment. There is a difference in the quality of equipment, the better quality, the more sensative it is.

[Cygnet]

My grandfather used a chunk of uranium as a doorstop for years. It was heavy. I think it's in my back yard now in a pile of other rocks; I'd have to check to see for sure.

Uranium ore is fairly low in radioactivity; it has to be refined before it's dangerous. That said, all you probably need to do is call the local geology department of a nearby college. They'd surely have someone on staff who could help you.

Leva

[MELOC]

i saw an interesting episode of CSI yesterday where the investigators needed to check for radioactive particles in some evidence. they exposed the item to photographic film. the radiation showed up as bright spots. since the object was exposed to the film in total darkness it showed no detail from light, only the x-rays from the radioactive substance were exposed.

so if you can find a way to expose a sample on some photographic paper or maybe some poloroid film, that may be useful.

[Ross]

Thanks guys the boy does want to be a geologist so i don't mind spending a bit to get him something useful. My stepFIL worked at NRC so I'll ask him.

[reitenger]

I'll have to look in the building this weekend, I think I still have a military surplus one running around here. If I do, i'd sell it to you fairly cheap. I used to work heavy equipment repair, and one of our clients was a facility that handled a lot of radioactive stuff, so I would check out their equipment before I would touch it. They had to bury a couple of pieces because they would max the meter.

[Oldotaku]

Old Civil Defense geiger counters are pretty cheap. Just see that it works: ask questions about it.

If you do decide to go the used Civil Defense counter route, the machine you want is a CDV-700, preferably NOT an Electro-Neutronics unit. The other members of the CDV family of counters are "War Meters", or insensitive ion chamber meters, that measure up to 500 R (600 R is a lethal dose). Meters to avoid are CDV-710, -715, -717, and -720. There are other meters in the CDV family, but are considered rare collectors items, and are priced even higher than the GM-10 you're looking at now.

Another alternative are the Russian "dosimeters", or pocket-sized geiger counters, also available on Ebay. Harbor Freight also had one for a while for $50, but some of the Ebay ones are as little as $20 plus shipping.

Beware of getting meters made much before 1965 or so, as they will have tube technology, and will probably require two 67.5 volt or 90 volt batteries ($20-$40 each), in addition to one or more D-cells. They may also have 1B85 geiger counter tubes, which are notoriously thin-walled and prone to collapse, becoming useless. Even more expensive are the Precision Scintillators, like the 111B gun-style detector. While being incredibly sensitive, the detector element was poorly sealed, converting the machine into a doorstop. You can't find that out until you've invested nearly $100 in batteries though .

[dale]

your local fire dept may have one or two laying around... i know ours do and we never use them...

just a thought
dale

[amelia]

Check out www.radmeters4u.com. There's a lot of good information there.

[Ross]

Thanks again all, the link was very informative (I was given it by Comfortably Numb as well) but the equipment isn't really what I need. These survey meters will tell you if there's been a nuclear accident, but can't give you much information about a mineral sample, especially about a low level of radioactivity. I ordered the GM10 as it is a real geiger counter and has software to chart both decay and exposure (acts as a dosemeter too)It also can record alpha beta and gamma radiation which the survey meters only cover the 2 seriously problematic ones. Still if your interest is in the mineral as a sample all three become important! I'm sure if my boy stays at the geology thing (as he has for 12 of his 14 years) it won't be his last one and at $188 delivered its not such a terrible expense. If I did want a survey meter radmeters4u.com would be the place I'd buy one from, and they're not really alot more than I spent