Live real-time monitoring map of radiation counts in the USA

You mean we’re not extrapolating averages across large intervening regions devoid of any volunteer’s gieger counter?!

Here’s the iPhone app you’ve all been waiting for. the iPhone iMeter….it’ll meter anything you need to meter on your iPhone!
It’s accurate, reliable, instant unit conversion, portable, affordable, NIST traceable (no, it’s a different NIST..), and best of all, it’s only $.99 at the ap store.
Just point your phone at whatever you’re needing to measure, and slide your finger up on the screen to give the desired reading.
THIS is the ultimate alarmist tool! I use it all the time to detect B.S., or show people how CO2 is rising as we speak. Now, measure GoreRads in situ, in real time, and scare everyone with claims of dangerous something-or-other whenever you want to.
http://www.apptism.com/apps/imeter
(believe it or not, I’ve actually convinced a few people that it’s real…..groan….)

Geiger counters of this sort are good when looking for gross radiation levels, but do not tell you how that may translate into exposure rate which is the measure of potential dose (not necessarily the dose you are actually getting). I prefer what is called a microR meter for measuring my background levels. The microR meter is much more sensitive and the reading is easier to interpret for significance.
Anyway, if you insist on buying a Geiger counter, here are some tips:
When using a Geiger counter like this, seeing spikes of two or three times normal background is not unusual, so don’t panic if it does this. Background radiation varies considerably from daylight to night time, so expect this. If you move the meter around, expect variation. I don’t know about this particular meter, but just the motion of moving the meter will swing the needle on some meters (geotropism) and give you a false reading. The detector should be facing up if you are measuring background airborne contamination such as we may get from Japan. However, areas with relatively high radon levels may cause deposition of radon daughter products on the detector causing elevated counts over time, so I put a piece of tissue over the detector (I lose alpha counts doing this). Be careful where you put the meter, you may be in a naturally “hot” area. Be careful what you bring around the meter, there are lots of things in our personal worlds that can cause elevated counts.
You can distinguish alpha, beta or gamma emissions by doing the following:
1) put a piece of tissue paper over the detector. If the counts drop dramatically you are measuring an alpha emitter. Side window detectors, such as seen on the old Civil Defense meters, won’t detect alpha particles. Even pancake detectors such as used by the Inspector above have a very low efficiency for alpha particle detection. So if you see a dramatic drop when you put tissue over the detector, you have a serious radiation problem.
2) Put a 3/8 inch piece of plastic or wood over the detector. If the counts drop dramatically you are measuring a beta emitter such I-131 (also a gamma emitter so it may be a little confusing). The pancake probe on the Inspector is typically about 30% efficient.
3) If the counts don’t drop much after doing the above, you are measuring a gamma emitter such as Cs-137. Most of your normal background counts are X-ray/gamma emissions from the sun and natural radioactive materials that are all around us.
If you spill something on the detector, don’t try to clean it yourself – guaranteed you will ruin the detector. Have the manufacturer replace it. If your Geiger counter has a cable for the detector, it is not unusual to see the cable go bad and it will peg your meter. Don’t stick your tongue to an attached cable – there is about 500-1000 volts running through it. The window on a pancake or end window detector is fragile – I had a stalk of stiff grass break one ( I won’t say how many I’ve broken).
How do you know your detector is calibrated properly? You won’t. However, if you can get hold of a source of radiation such as old, orange FiestaWare, you can see if there is any change in your detector over time. It is critical, if you do this trick, to make sure you maintain the same geometry each time, i.e. the exact same distance from meter to source and exact same location of source relative to detector. With a uranium source such as found in FiestaWare, you should see very, very little decrease in counts over a year or more.
The above are just a few things you need to understand when using a Geiger counter. If you do not get decent training on how to properly use a meter like this, I personally think you are wasting your money, but it is your money and I like most of the companies that make radiation detectors so be my guest. Proper training also includes a course on how radioactive atoms and radiation interact with matter and, by extension, the detector.

For the Tokyo Geiger counter readings – I hope they’re not taking those readings INSIDE their office building. If you read their site literally, that’s what they are doing – and that won’t be representative of the dose rate outside. For that matter, you’ll get a boatload of building effects on the plume pathway in a city – can easily wind up with some spots significantly higher dose rates and others significantly lower, all based on how the wind is blowing through the city & around and over the buildings, and how each building is causing turbulence, flow disruptions, pathway deviations, etc.