What I learned from buying a Geiger Counter

How much radiation are we really exposed to?

The interesting thing about a Geiger counter, unlike other measuring tools like a thermometer or a light sensor, is it measures something that otherwise is completely undetectable to us. It’s like having a six sense, you really gain information about the environment that you did not have before. The first thing I realized is that we’re constantly bombarded with radiation all the time, whether your outside or inside, night or day, you’re taking hits every second. The main source in general is cosmic radiation, from the sun and deep space we’re getting little particles flying at us all the time. This radiation usually fluctuates between 10 and 20 CPM (Counts per minute). After turning it on for a while and coming to terms with the fact that we’re all being radiated every moment of our lives, I was curious about finding real sources of radiation.

I’ve taking the Geiger counter to a lake and walked around, I’ve held it up to some big rocks that people put to border their front yard as I heard Granite can sometimes contain increased amounts of radiation. I’ve taken it around large brick buildings and regular concrete buildings and so far I haven’t been able to detect any real difference in radiation anywhere. At first I thought that some places might have been getting higher radiation levels than others but there’s just random fluctuations in the amount of radiation you’re getting at any given time. You might get a reading of 21 and then if you wait there for 20 minutes you’ll get a reading of 8. There’s a constant flux of the amount of radiation passing through us.

I went to Magnuson Park building 27 near Seattle which used to be a naval base that used to house some radioactive materials. Interestingly enough not to make any kind of weapon but to coat instruments so pilots could see them in the dark. I walked around a bit but I couldn’t detect any difference between the average radiation you get everywhere. Apparently in 2015 there was a cleanup project to make sure the radiation levels were low and it was deemed safe. In order to get really accurate readings you’re supposed to take your Geiger counter and hold it very low to the grounds the lower the better but I prefer not to walk around drying a bunch of attention to myself in public places.

I’ve heard certain rocks can happen to contain larger amounts of Uranium that average, but I haven’t found anything. I quickly learned for the most part, walking around with a Geiger counter is pretty uninteresting. The easiest thing most people can do to find some elevated levels of radiation and and check the smoke detector in their house. I tried two, one of them didn’t seem to give off too much radiation, but one of them gave me about 30 CPM which is higher than I normally get anywhere else. Smoke detectors use a tiny amount of a radioactive isotope called Americium-241.

I was curious to see something more though, so I finally found a shop that sold Uranium glass. Uranium glass is regular glass that has had Uranium added to it before being melted. It actually looks very cool and glows under a UV light.

At one point the CPM got above 50, which is more than twice the high end of what I normally see. Even this radiation level is pretty safe, and the further away you are from something emitting radiation the safer you are as the inverse-square law applies here. The manufacturing of this type of glass stopped during the cold war when almost all of mined Uranium was going towards the creation of nuclear weapons. Although it’s fairly safe, it’s not recommended to eat off of as you don’t want acid from foods, abrasion or chips freeing Uranium and it getting into your body.

There is another item, vintage Fiestaware, particularly the bright red-orange color produced between 1936–1943 and 1959–1972. It is radioactive due to uranium oxide in the glaze. You can find this on Ebay and sometimes in second hand shops, but I haven’t been able to locate any there so far. These actually radiate between 1000 CPM and 30,000 CPM. This sounds alarming but it’s actually not too dangerous. Like Uranium glass you don’t want to eat off of it, or be in close proximity to it for long periods of time. You wouldn’t want it sitting on your night stand.

Riding on an airplane will get you 100-300 CPM, living in Denver will get you about 30-100 CPM. In everyday life, radiation is not something you have to worry about. Almost. There is one thing. If you have or especially live in a basement, they can fill up with Radon gas which is naturally produced underground. While the radiation isn’t that high in CPM terms, it can decay into particles that can get into your lungs. Modern houses should have vented basements so this kind of gas doesn’t build up, but if you live in an older house you may want to buy a Radon test kit.

So what about serious levels of radiation? There is a place called Hanford in Washington state that was built during the Manhattan Project during World War 2 to produce Plutonium. A lot of it leaked into the ground and groundwater. Normally the radiation levels aren’t too intense, but there are some areas that are restricted to the public where the CPM up to 20,000 to 100,000 CPM.

Then there is of course, Chernobyl. The site of the worst nuclear accident in history. Most Geiger counters are going to max out at around 100,000, and if you are right at the site of the nuclear reactor, or especially the Elephant’s foot, you are going to getting doses in the trillions. Although no one would be able to detect it as none of your electronics would be working at this location. You wouldn’t be working either, as death certain within a few minutes.

At this point, CPM isn’t really a way to measure this level of radiation, the Elephant’s foot is around 10,000 Sv/hour. While a Geiger counter measures how much radiation is being emitted by an object, the Sievert (Sv) specifically measures the potential health risk on a human body. In a nuclear reactor you can have 10,000 to 100,000+ Sv/hour levels of radiation. And of course you have a nuclear bomb going off, where the radiation during the time of impact would reach millions to billions of Sv/hour. This is a bit misleading though as the explosion is very short lived, so you would never actually get an hours worth of radiation from it.

While standing right next to a nuclear bomb detonating is the highest amount of radiation that will ever occur on earth, I think. I can’t predict the future. There is something even higher. If a super nova went off at the distance of the sun, it would produce around 100,000,000,000,000 Sv/hour. This dose would of course destroy all life on Earth, aside from the radiation, it would also blow the atmosphere of Earth into space.

Lucky for us there is no chance of the Sun going super nova.