Upon beginning the review of this product, my pet cat ran over my keyboard as I was trying to run a test, and I was heard to remark "That stupid cat wrecked my dryer lint radiation experiment!" As soon as my brain registered what I said, I knew it was sad confirmation that I am indeed one of the world's biggest nerds.

Seriously though, besides being nerd fodder, the GM-10 radiation detector would do an excellent job in industrial applications, classrooms, and for the general hobbyist. Why? Because it's well-designed, easy-to-use, and works, that's why!

Before we get into how the GM-10 works, let's look at the unit first;

The design is small, yet not at all delicate. I would not worry about students handling this unit at all - it has a very durable case - but as with all such detectors, they have a delicate tube inside so you probably don't want to drop it.

The GM-10 now ships with a USB connection so you can hook up to a PC or Mac easily.

You'll also recieve the software (MacOS 7.6-9.2.1... OSX not supported) on CD for your GM-10, called "RAD" (Radiation Acquisition and Display) - check out the cool icon!

Using the GM-10 is really very simple - plug it into your computer, and start up the software. The unit does not require a power cord, so if you've got a laptop, you can easily collect remote data. If your speakers are working, you'll immediately hear the clicking sound of radiation counts recorded by the detector.

So what are you detecting? The GM-10 will detect alpha, beta, gamma and x-ray radiation. Want some ideas for radiation sources? Black Cat Systems has put together a fascinating page describing common sources of radiation, a must read before you start playing with your detector (it's a must read, regardless!)

Listening to the speakers alone gives you a good idea of the amount of radiation present; the GM-10 reported about 10-14 counts per minute (CPM) for my household background radiation. But you can also see the radiation levels constantly updated in a digital display, and an automatically updated graph (please click on the image for a full-size view);

The above is an example of the sensitvity of the GM-10, I placed some salt substitute (potassium iodide) in front of the detector, and the graph showed a jump in radiation levels over the next couple of minutes.

I couldn't resist tearing apart my smoke detector to expose the radioactive Americium inside. I got a massive spike in rad levels, over 18,000 CPM, before I lost my nerve and put it back into the smoke detector housing!

The graph display will auto-scale to show all of your CPM on the Y-axis, which is a nice touch. I did have the small problem of the last digit being cut off in the display when the GM-10 reported 5 digit numbers, so there appear to be some small bugs to be worked out. It would also be nice to be able to compare data runs in the graph window, but the display is only capable of reporting the current data run. You can however, record the data to a file (just raw data in a simpletext file), then use a speadsheet to display multiple data runs.

The bottom of the display has six easy access tabs that hold a wealth of features. The basic graph controls are there, but you can also fill under the curve which is a nice way to clearly see changing levels. There is also a trend selection that is supposed to draw a best-fit line, but it wouldn't work for me. I like the time-stamp feature, but be sure to enable it before you start a data collection run, because it will clear your data if you press it after the fact.

Simple statistics and recording controls are included, but you also get the ability automatically to upload images of the graph via ftp, allowing you to report real-time radiation numbers over the web - cool!

On the whole, this is a tremendous bargain and a very capable detector, I look forward to using it in physics class and reporting experimental results to y'all! The RAD software is still a little rough around the edges, but knowing how hard the author has worked at producing exceptional pieces of Black Cat Software such as The Atomic Mac, I wouldn't be suprised to see the bugs ironed out quickly.

So order youself a GM-10!

Updated May 5, 2002

I recently received my vaseline glass bead from BlackCatSystems - they sell them as a safe source of radiation for use with their GM-10 radiation detector. Although there is a great demo of it on the excellent BlackCat radiation page, I couldn't resist playing with it myself - here's what the bead looks like:

And here's what it looks like when exposed to UV light - cool!

My camera didn't do the eerie green glow justice! Besides being a cool glowing bead, I can't wait to give it a try with the GM-10 radiation detector in physics 30 class. I'll be sure to report the results to you!

Updated January 7, 2002

Some more details...

a neat note for those of you who might want to convert the counts per minute of radiation into an actual radiation amount:

"BTW - for the GM-10 1 CPM works out to be about one (0.95) microRem for gammas (energy dependent of course), which is pretty handy."

He also refers to a VERY interesting set of radiation detector readings on a plane flight:

"Take a look at my updated radiation experimentation page where I have a graph of data I took last week with a GM-10 aboard an airplane flight from Baltimore to San Francisco. 30 times background! Might be interesting for some of your readers. (Radiation due to cosmic rays that normally are blocked by the atmosphere)"

I wonder how Chris got that little mysterious radiation detector box past security?!?

Updated February 28, 2002

You may have already read the review of the affordable GM-10 radiation detector from BlackCatSystems. Well, the ever-industrious creator of the GM-10 has come up with a bigger brother - it's the GM-45:

The GM-45 is more sensitive than the GM-10, as the creator puts it:

"Just a quick note to let you know the GM-45 is available. It's like the GM-10 except it has a *huge* pancake style GM tube, almost 2 inches in diameter. This results in many more cpm for a given sample."

At $299 US, the GM-45 is ridiculously low-priced for a sensitive radiation detector - a perfect solution for high school physics. Visit the GM-10 and GM-45 page for more information, and note that on the same page you can also order vaseline glass beads as a safe and convenient (and interesting) radiation source.