These past few weeks, the world's eyes have been closely monitoring the situation in Japan. After a devastating earthquake and tsunami, the country now faces issues from a damaged nuclear power plant. Just this past week actually, radiation particles reached Colorado (though in very, very miniscule amounts). The radiation here isn't harmful at its current levels, but it certainly makes this tragedy hit a little closer to home. We at SparkFun have many ties to Japan and are keeping everyone there in our thoughts.
The SparkFun Geiger counter.
Shigeru Kobayashi, he of Arduino fame and a SparkFun customer, lives in Japan and has experienced the tragedy first-hand. Shigeru wanted a way that he could monitor the radiation levels at his home and compare them to other regions. So he bought a SparkFun Geiger counter and mated it to an Arduino board and a wireless LAN converter. He then interfaced the counter with Pachube.
Shigeru's project in its enclosure.
The results are impressive and give him an excellent way to monitor the radiation his family experiences at their home in Japan. Here is an article he wrote detailing how he used the counter. It is a Google translation from Japanese, so be forewarned that some parts of it might seem a little fuzzy. The general explanation, however, is excellent. Great work, Shigeru - and stay safe!
One final note, if you are interested in the SparkFun Geiger counter, they are currently out of stock. We are working on building more, but as you can imagine, our supplier is under heavy demand right now. We will get more in stock as soon as we can.
relevent and
relevent
just as relevant.
FYI, the first link I posted was actually the source for the XKCD post.
Take note, all, that you'll want to remove the red cover and expose the tube window to air. There's not a chance an alpha will get through all that, and even betas will get backscattered to an unnecessary degree. Luckily this isn't an energy-sensitive detector (it is basically a diode that has an avalanche breakdown whenever a particle or gamma photon comes through the window, but the current isn't proportional to the particle energy like a solid state detector is), but it'll still be a problem if you're backscattering 80% of the betas that would otherwise come in.
Thanks @alexw for catching that! Yes, you definitely need to remove the red cap to properly detect alpha and beta. The reason for the cap is to protect the thin layer of mica on the end window during shipping.
Also, the enclosure will block events as well. You really need the end window exposed to properly detect alpha and beta. Gamma is a whole different beast than charged particles.
We've probably exceeded our lifetime dose of UV radiation many times over & are a few sunny days away from death, yet this meter only detects the radiation there's hardly any of.
I spent about 3 years within a 150ft of a nuclear reactor. I was stationed on an SSN early in my navy career. My exposure underway was actually less than being in port unless I spent a lot of time aft where the diesel tank doesn't provide additional shielding, but even then I was still nowhere close to my exposure limits.
What I find amusing about this is people are buying up old cold war era civil defense meters and all but a couple of models only detect high energy gamma emissions that would be expected from a nuclear attack. I was trying to bid on one of those old units to gut and use as a project enclosure but even with the broken ones I was getting outbid rather quickly.
The particles seen in the US will be primarily be alpha and beta anyway so those gamma units are pretty useless.
I'm also in Japan and on the waitlist for one of these, looking forward to it very much.
Check here http://www.goldmine-elec-products.com/prodinfo.asp?number=C6986
They have some other kits but make sure the tube used detects at least beta and even better if you can find an alpha/beta tube. They have a lot of gamma only tubes that won't be as useful.
If you want to go "the next step" with detecting/measuring ionizing radiation, you'll want to build a scintillation probe. A scintillator is far more sensitive than a Geiger tube. A scintillation probe is typically a combination of a 'scintillator' material (there are many types) optically coupled to a photomultiplier tube. In addition to being much more sensitive than a G-M tube, with appropriate electronics it can discriminate between various isotopes. A project I did is at:
http://tech.groups.yahoo.com/group/GeigerCounterEnthusiasts/files/Dentillator%20project/
Pete
I just got my Geiger Counter on Pachube a couple days ago, located in South San Diego county. I'm using an Arduino, XBee+USB, XBee+Explorer, SBM-20 Russian Geiger Muller Tube, and plan on replacing the XBee's with Ethernet or Wifi.
Real-time radiation monitor radspot.org made with Geiger Counter, Arduino and GPS. Source code available as well.
I recently came across a twitter feed of one of our Geiger counters mounted to a roof of a house near the coast in Monterey, California. It's got a live view as well as logs.
I'm one of the folks who were lucky enough to get one of these before they sold out. I've interfaced mine to an 18F2520 and an LCD, because I didn't want to risk mucking up the firmware on the working counter board. I am working on getting it calibrated to read in mRh and υSv, but currently am just using CPM. For those who are interested in a very human connection to events in Japan, I recommend the feed from Katz at Yokoso News http://yokosonews.com/live/ .
For anyone who is curious about the current status of the reactor and the region, Nuclear Energy Institute provides a fast updating news source with lots of information.
http://nei.cachefly.net/newsandevents/information-on-the-japanese-earthquake-and-reactors-in-that-region/
disclaimer: NEI = nuclear industry lobby
Radioactivity emitted from Nuclear fuel is both particular and EMR. Alpha and Beta particles are ejected bits of the atom while Gamma radiation is an electromagnetic wave of very short wavelength.
Alpha radiation consists of two protons and two neutrons bound together into a particle identical to a helium nucleus. Beta radiation consists of high speed electrons or positrons. Not all Geiger counters will respond to all three types of radiation.
Why is it people say "radiation particles"? Particles of radioactive material would be ok. Or radioactive particles. Or even radioactivity. Typically, there is some radioactive matter that has been wind-born or, in Japan, from contaminated ground water seepage. The better articles I've read talk about detecting cesium or iodine isotopes.
As morbid as that sounds the iodine might not be such a bad idea.