Edit 6 weeks later: with use, I think I actually like and recommend the cheaper one more.
I own both of the above Geiger counter / radiation detectors. (Note: they’re measuring different samples here.)
The one on the left is the EcoTest Terra-P. It’s made in Ukraine and costs 200 dollars on Amazon, get it here. (and ONLY get it there. That’s the manufacturer’s store on Amazon. And there are a lot of fake versions of these.) It’s the most popular one in Ukraine, a place that is no stranger to radiation.
The one on the right is the Waysear no-name one. Well, the name is on it in Chinese and I can’t read it. But it’s a great tool for the 80 bucks it costs. Get it here on Amazon. (And again, only get it there, that’s the manufacturer’s store on Amazon.)
I bought these when I found out the governor of Wyoming, the state where I live, was planning to store Nuclear waste 40 miles upwind from me. It would maybe be safe just sitting there, but not if there’s a fire, bomb, terrorist action, etc.
That plan is on and off again. Currently it’s off, but it could be on at any time. They say they’ll get ten million bucks a year for it after paying to take care of it (probably by the lowest bidder). The State should just legalize weed. They’d make ten million a month just ganking people with the weed taxes. But Wyoming will probably be the last state to do so. Because people who want to park nuclear waste 40 miles upwind know what’s best for our health.
But as I started reading about nuclear power (after I watched the HBO series, Chernobyl), I decided I should have a Geiger counter (or two). These are the two inexpensive ones I’d recommend. If you can only afford the cheaper one, get it. If you can afford both, get both. More on that later….
I also recommend you get a very weak radioactive source to test them, so you know that they work, and you can confirm down the line that they still work. I wouldn’t keep the source in your bedroom, but keep them out of the reach of children. I recommend a small piece of uranium ore, you can get that on Amazon for 40 dollars here, or for even less, here. Here’s some I bought on eBay, though eBay can be a crap shoot. Though I’ve had good luck with this guy and this guy and this guy.
Don’t touch the ore, and wash your hands after handling them. Don’t get any flakes or dust from them anywhere, don’t breathe it. Uranium is radioactive (mild in ore), but is also toxic to ingest, in the same way that lead is toxic.
For a weaker test source, you can try uranium marbles. 14 bucks here. Those have no dust that will flake off, unlike ore.
Also, check around your house with your counter. A lot of things are radioactive. Even old dishware, like antique Fiestaware.
One common item that’s radioactive (and “hotter”, more radioactive, than a lot of uranium ore) is older Thorium lantern mantels for kerosene or white gas camping lanterns. 
If you get these, keep them in the package. Not only are they radioactive, thorium is a bit toxic outside the radioactivity, like lead.
Note that there is background radiation in the world, from radioactive decay deep underground, to gamma rays coming from space. In fact, you get more of that when you’re in an airplane, because there’s less air above you to block it.
Background radiation on earth ranges from .1 microsievert (uSv) to .3 microsivert. But .3 would be high. Where a guy I know lives in Maine, his background is .1 and where I live in Wyoming (where a lot of the uranium in America is mined) it’s about .15
In my basement it’s .18 because we have a radon problem (though it’s mitigated, it used to be higher.)
If you have radon, check the air filter in your basement furnace. That’s about .23 uSv there at our place when it’s time to change the filter, because the filter traps radon. Radon is a byproduct of natural decay of uranium, but can occur in houses in areas with no deposits of uranium or other rocks. It can also exist where bricks in construction are made out of gravel containing some amount of uranium ore. With underground uranium, radon comes from deep within the earth and rises because of heat in the earth. And because, even though radon is the heaviest elemental gas, it’s far lighter than rock and dirt. But once cooled near the surface, it settles in basements because it’s so much heavier than air.
.
When the USA made the atomic bomb, they thought they’d have a monopoly on the atomic bomb, because they thought uranium only occurred in a few states in the US South West and Mountain West. Turns out, uranium is fairly common all over the world:
Here are the main USA deposits of uranium:
Some granite rock used in kitchen counters is naturally slightly radioactive. So if you have granite, check it with your counter. More info on that here.
EXPOSURE
If the background ever shows as is over .5 uSv on your Geiger counter for a sustained period of time, that’s probably time to worry. But still not absolutely dangerous, especially if for a short time.
Radiation poisoning is dependent on:
1. Strength of source
2. Distance from source
3. Amount of time you’re exposed.
It’s also dependent on the type of exposure. Being near a gram of uranium 238 metal for a few minutes won’t harm you. But if you machined that, it would burn and produce radioactive vapor. If you breathed that vapor, it could make you very sick, and also possibly give you cancer years down the line.
Note that Geiger counters can give a false reading for a few seconds when you first put it against something (sort of a proximity effect) but will go down quickly if the sample is not radioactive. If it is radioactive it stays near the reading. And the reading of something radioactive will fluctuate. That’s why both of these Geiger counters give averages.
Try not to put the back of your counter on a radioactive source, it may leave physical dust or particles that will give a false higher reading on things. If this does happen, wipe off with a barely-moist napkin, then wipe with a dry napkin or paper towel. Do not get liquid in the unit.
There is a misnomer about radioactivity (actually a lot of them.) Exposing something to radiation does not make them radioactive. People who were exposed to radiation at Chernobyl were shown in the HBO series as being “untouchable.” If they still had fallout or radioactive particles on them, touching them could harm you. But if they’d taken a very good shower, and their clothes were thrown away, they would not be radioactive and you could hug them. (Though it might be painful to them because of radiation burns).
The damage to them is already done from the initial exposure. But they would not be contagious.
Hint: if you get exposed to radiation, bathe with soap and wash your hair with shampoo, but do not use conditioner. Conditioner makes some of the fallout stick to your hair.
Fallout is a physical thing, ranging in size from ash like you’d have from a fireplace, down to dust to microscopic particles. But it can be washed off of you.
I got some sheet lead on amazon and made a box to keep the samples in. I just took a small cheap aluminum briefcase type box and lined the insides with the lead. I taped it down with duct tape, completely covering it. I wore disposable gloves to do this, and wore a particle mask. Remember, lead is toxic. But it does a great job of blocking radioactivity. This is 1/64th of an inch thick. You can get thicker, but it will be almost impossible to bend at 1/16th, and very difficult at 1/32nd of an inch. If you need thicker than 1/64th of an inch (doubtful with the samples I mention), get 1/64th and double thick it. Yes. Double thick it.
Here’s a pic of the box about half-way through adding the lead to the box:
THE ADVANTAGES OF THE ECOTEST UNIT ARE:
–It’s more accurate by 15 or 20% than the Waysear unit.
–It gives a reading of all-time radiation exposure over time (on the second screen). It’s reset when you change the batteries. (Sieverts are cumulative: 1 millisievert per hour exposure for 24 hours would be 24 millisieverts.)
–You can sort of choose when to measure alpha rays. There’s a compartment on the back aside from the battery compartment that covers the fragile Geiger tube. It’s lined with lead. If you take that off, you can detect alpha rays.
–It comes with batteries. Cheap ones, but it will work right out of the box.
–It sort of works when off. It’s supposed to be in a sleep state when off and will sometimes sound the alarm when it goes over the threshold. But the threshold is set at .3 and you can’t change it. Well you can change it, but it resets when you turn it off. But I’ve had it wake me up with a false alarm, since the threshold is so low.
–Long battery life.
–Small. Fits in any pocket.
Pro tip for this unit:
The little metal conductor that ties the two batteries together at one end falls out easily. Don’t worry, just put it back in.
It doesn’t have to connect inside, it is only to connect the two batteries on that end.
Here’s a PDF of the manual for this unit.
It can read much higher amounts of radiation. The cheaper unit only goes to 99.99 uSv.
THE ADVANTAGES OF THE WAYSEAR UNIT ARE:
It’s less than half the price of the Ecotest unit. And it’s accurate enough to tell you “all clear” or “yikes.”
–It takes a reading fast. like starts showing in 5 seconds or so.
–More sturdy construction than Ecotest.
–Backlit screen. Can see in any light.
–You can leave it on, it doesn’t shut off.
–You can change the threshold. (I love that.) Use the button that looks like a thermometer for that. The settings you can set are .5, 1, 2, and 5 microsieverts.
–The clicks and alarm are quieter.
–Simpler interface. None of that “one button for 4 functions” crap.
–Detects x-rays along with gamma and beta. The yellow one detects gamma and beta, but not x-rays.
–You can mute alarm, so fun for undercover, checking books in the library or whatever. Use the button that looks like a speaker for that.
–You don’t have to take off the back cover thing to read beta particles. It measures a total of beta, gamma, and x-rays. (The Ecotest does not detect x-rays.)
–Long battery life.
Note, it does not come with batteries. You’ll need to get two AA batteries. (not AAA like the yellow one.)
I’m not linking the manual here, it’s fairly useless, but the unit is much more intuitive, and I basically tell you how to use it in this post.
More on the Ecotest unit:
That’s the only drawback, and it’s a tiny one. Also you cannot skip the start screen, you have to start the middle arrow key every time to start taking a reading. Still, tiny issue compared to all the pluses.
Top number is current reading. Bottom number and graph below that are the average since you started taking a reading.
When it stops blinking, it has the average.
After 8 minutes, you’ll hear one beep, when it’s got an average. (shown continuously in the graph at the bottom of the screen).
Takes 2 or maybe 3 minutes. Will still change a little from there, but that’s your average.
If I didn’t explain clearly, hold the right button down for 5 seconds to turn it on. Do the same to turn it off, though it will turn off after a while on its own.
That’s what the 4th reading is, the second clock: to leave it on for hours to check an area, and not have it turn off after a few min. Haven’t tried that yet.
These units will not tell you what KIND of radioactive material you’re measuring. For that you need a scintillation counter, which costs a lot more. They also won’t detect minute normal amounts in food, that requires very expensive gear.
These units will not detect the Americium in a smoke detector or the tritium in a gun site, unless you break them open. And I REALLY do not recommend you do that. Toxic!
WHAT TO DO IF THERE IS A RADIOACTIVE LEAK WHERE YOU LIVE
It doesn’t mean certain death. If it’s a high amount, STAY INSIDE. Some isotopes have a half life of millions of years, but some of the more prevalent ones, Iodine-131, has a half life of 8 days. Stay inside, tape shut any doors or windows that leak a little wind, and turn on your radio to find out what’s happening. Though the radio might not be accurate. The Soviet Union didn’t tell people near Chernobyl right away. I lived 60 miles upwind from the 3-Mile Island plant when that was leaking radiation. I was at boarding school, and the school didn’t tell us about it because they didn’t want us to worry. (This was pre-Internet).
I bought some iodine 130-mg pills. If there IS a radioactive event where you live, taking ONE of these a day will help prevent thyroid cancer, which is a common effect of radioactive accidents. Do not take MORE than one a day, it doesn’t help, and can harm. “People at risk of exposure to environmental radioactive iodine (iodine-131) in fallout may be instructed to take non-radioactive potassium iodide tablets. The typical adult dose FOR RADIATION PROTECTION is one 130 mg per 24 hour (from here.) That is MUCH higher than the normal daily dose, and that much should only be taken when radiation threat is happening. And take t for a week. Normal dose is 220 MICROgrams. Radiation dose is 130 MILLIgrams per person per day for one to two weeks.
If you want to go prospecting for uranium (and other radioactive) ores, it can be helpful to have a UV (black light) flashlight. I got this one for 12 bucks. I love it. Takes 3 AA batteries, and puts out a lot of UV (as well as some visible, and a little heat. It kinda burns through batteries, by the way.) It’s safe to shine on things, but do not look into it or shine it on animals’ eyes. It’s not dangerous like a laser, but it is a very bright light you mostly can’t see. I’ve shined it into my eyes. Looking into it from a foot away feels like looking into an older car headlight at a dozen feet. So don’t do that.
Some radioactive ores will fluoresce (glow brightly) under a UV light. Some will not. And a lot of non-radioactive minerals will fluoresce under a UV light. So if you go looking, you could shine this on rocks, and if they do fluoresce, check them with your Geiger counter.
The UV flashlight is just a lot of fun too. You’d be amazed how many things in a home fluoresce, often different colors than they are in regular light. Also, you can find pee, spit, blood, semen, real pearls, and scorpions. The UV flashlight can also be used to see if US (and other country)’s paper money is counterfeit. Supposedly this doesn’t work correctly on the 100 dollar US bill, but all the other US bills have strips that are different colors and in different positions for each bill:
Here’s a short video on doing this with US bills.
Here’s a video on doing this with bills of many different companies.
If you’re not in the USA, google
UV light detecting counterfeit bills from (your country.)
WHAT YOUR GEIGER COUNTER READINGS MEAN
Note that these are in MICROsiverts, not MILLIsieverts. 1000 micro = 1 milli. Both of the Geiger counters above measures in microsieverts. Though the second page of the ecotest (the page that shows accumulated dose) is in Microsieverts.
In the HBO show Chernobyl, they’re using a (less used now) unit called roentgens.
1 roentgen = 9329 micro-sieverts. Here’s a conversion calculator: https://converter.eu/radiation_exposure/
|
Event
|
Radiation reading, millisievert (mSv)
|
|---|---|
| Single dose, fatal within weeks | 10,000 |
| Typical dosage recorded in those Chernobyl workers who died within a month | 6,000 |
| Single does which would kill half of those exposed to it within a month | 5,000 |
| Single dosage which would cause radiation sickness, including nausea, lower white blood cell count. Not fatal | 1,000 |
| Accumulated dosage estimated to cause a fatal cancer many years later in 5% of people | 1,000 |
| Max radiation levels recorded at Fukushima plant yesterday, per hour | 400 |
| Exposure of Chernobyl residents who were relocated after the blast in 1986 | 350 |
| Recommended limit for radiation workers every five years | 100 |
| Lowest annual dose at which any increase in cancer is clearly evident | 100 |
| CT scan: heart | 16 |
| CT scan: abdomen & pelvis | 15 |
| Dose in full-body CT scan | 10 |
| Airline crew flying New York to Tokyo polar route, annual exposure | 9 |
| Natural radiation we’re all exposed to, per year | 2 |
| CT scan: head | 2 |
| Spine x-ray | 1 |
| Radiation per hour detected at Fukushimia site, 12 March | 1 |
| Mammogram breast x-ray | .40 |
| Chest x-ray | .10 |
| Dental x-ray | .01 |
———
Fun facts:
Uranium is named after the planet Uranus.
Plutonium is named after Pluto.
RIght… but while the Terra-P lasts for years at least, the Chinese crap stops working after a year. Or, should I say, it shoots straight to 99.99 upon turned on. Very useful.