-----BEGIN PGP SIGNED MESSAGE-----
>> An Alpha particle will kill or mutate any cell it hits, a rare neutrino that hits
>> would be almost as deadly.
>Robert J. Bradbury <email@example.com> On Monday, August 02, 1999 >John, I'm almost certain this is incorrect.
> Radiation doses are moderated by virtually all intervening mass.
>The denser the mass the quicker the moderation. An alpha particle
>is a helium nucleus and gets moderated much quicker than other
>forms of radiation (because it is bigger and interacts more quickly).
A few inches of air or the thinnest tissue paper will stop an Alpha particle that's why Plutonium, a moderately strong emitter of Alpha particles, is pretty harmless as long as it's in one big lump (but not too big!) outside the body; only the surface material can gives off free particles and even those are stopped after a short distance. Plutonium only becomes the most deadly poison on the planet when it's in the form of a fine powder and is ingested into the body, either by eating it or breathing it into the lungs, because every Alpha particle then emitted will hit a living cell someplace and kill it, or far worse, mutate it. No cell can escape the massive damage of an alpha particle.
John K Clark firstname.lastname@example.org
-----BEGIN PGP SIGNATURE-----
Version: PGP for Personal Privacy 5.5.5
-----END PGP SIGNATURE-----