Radalert 100 Digital Radiation Monitor

I got my Medcom Radalert 100 Radiation Monitor (Geiger Counter) earlier this month (June 2012), and I've had a chance to play with it a bit. As far as I can tell, it performs accurately (but then I'm a teacher, not a nuclear technician).The baseline radiation in my area is reported to be 12CPM, and the Radalert 100 measures it between 10 and 12 CPM (counts per minute) every time I turn it on. I tested bananas to see if they are slightly radioactive (15+ CPM) due to the Potassium-40 content -- as I'd read somewhere -- and, yes, it's true.I dug up an old model smoke detector, and carefully disassembled it (which, incidentally, several federal agency websites recommended NOT doing). I found the small sample of Americium-241, in a metal-lined, plastic "can", with the metal cap. After removing the lid, and using the Radalert's mica ("alpha") window at the front of the Radalert, I rested the radalert flush on the edge of the "can" (positioning it about 1.5 cm directly above the Americium),and I got a much stronger reading (120 CPM). I verified there was some Alpha radiation by placing a sheet of standard typing paper (folded into a 4-thickness sheet) between the mica window and the Americium sample. Within a minute, the reading dropped from 120 down to 90 CPM. (Paper is an effective barrier to alpha particles.) I was expecting a much higher ratio of Alpha-to-Gamma particles (than 30:90), but now I have something new to research this weekend; this opens a new hobby for me and my kids: "nuclear energy" -- and possibly survival strategies in a post-Fukushima world. (Note: I duct-taped the metal lid back on the protective can, and the radiation immediately dropped to a little more than the banana had; I stowed the smoke detector safely away, out in the shed, away from my curious children. Be careful if you things like this; read several legitimate websites to understand the risks, BEFORE doing it.)I was pleased to see that the RadAlert 100 measured both the stronger Gamma radiation, AND the weaker Alpha radiation of the Americium. (Apparently this is what distinguishes true "Geiger counters" from simple "gamma radiation monitors," which are much cheaper to buy, but largely ignore alpha and beta radiation.) I am quite satisfied with my RadAlert 100.If anyone has tips for learning more about this device (or sources of useful information on the general topic of radiation -measuring, -hazards and -protective-measures), please drop me a line at: [email protected] Thanks! -- Dennis