(...) Uranium or thorium ores are easily found in mineralogic collections... very nice radio-sources ;o) Of course precise calibration is another story! See for example (URL) (19 years ago, 30-Jun-05, to lugnet.robotics.rcx)
(...) Much easier than that - run down to the local camping store and buy some gas lantern mantles. Unless they've changed something in the last five years or so, they incorperate a reasonable amount of Th-232 which makes geiger counters click (...) (19 years ago, 30-Jun-05, to lugnet.robotics.rcx)
(...) Also you are likely to get a reasonable reading from Smoke detectors - though please dont dismantle the one that could save your neck! Danny (19 years ago, 30-Jun-05, to lugnet.robotics.rcx)
