Vintage radioactive wrist watches - Is Radium really nasty?

[Katie Wasserman]

(01-19-2015 07:22 PM)jebem Wrote:  But the readings are real and gives us enough information about the radiation around us. For instance, inside home the background radiation is about 8 to 10 CPM and this value seems to be the usual in many places around the world.

This is typical for sea level readings from the tube you're using. If you buy an LND-712 you'll see somewhat higher readings as it's more sensitive, I find about 12 to 14 CPM is typical. I also have a much better GM tube counter that uses a 2 inch pancake style tube (with a mica window) that gives background counts of around 35 CPM. This one is calibrated too so I have something to compare my DYI counters to. I also have a few small radiations sources to test with.