Household Radioactivity

[BFLOOD@SLAC.Stanford.EDU (Bob Flood)]

Lantern mantles (is that spelled right?): some do, some don't. Not all
manufacturers use thorium - use a frisker in the store when you shop!

Speaking of throium, it's been used in lenses to obtain precise refraction
characteristics. Manufacturers are careful about how much they use these
days, but you may find measurable amounts in old camera lenses, binoculars,
or telescopes.

Potassium: cosmic neutrons traveling thru the atmosphere are moderated just
about the right amount to be very effective at activating potassium. A fixed
percentage of all potassium (I forget the percent, others may remember
better than I) is radioactive, whether the container is a KCl salt
substitute or a banana.

Watches/clocks: luminous dials use tritium/prometheum NOW! If you have your
grandfather's or father's luminous dial watch, it may be radium and the dose
rate on contact could be s few mrem/h (I have seen such a beast).

The smoke detector use of Am is probably the best case of that horrible
killer radiation doing something useful without harming a soul (with the
possible exception of reporters in need of someone being harmed in order to
make a living).
Bob Flood
Unless otherwise noted, all opinions are mine alone.
(415) 926-3793
bflood@slac.stanford.edu