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Radiation lesson.



Electromagnetic radiation comes in lots of useful forms. 

The kind most used for sterilizing is usually called ionizing radiation. That
can be anything from visible light and UV through soft to hard x-rays. While
capable of inducing serious chemical changes, and certainly of destroying
living tissue (right dose and wavelengths), it does *not* leave any residual
radioactivity. [Even mild, long-term exposure can induce mutations and thus be
carcinogenic (like visible light and long-wave UV causing skin problems).]

Much of ionizing radiation is poor at penetrating many solids, but all
materials seem to have windows that allow some radiation through (just like
glass passes sunlight). Lead, gold, and other heavy metals tend to be the most
opaque at all wavelengths.

Particle bombardment with neutrons and electrons (alpha and beta "rays") may
penetrate some materials and can cause residual radioactivity if they actually
split atoms into unstable isotopes. The kind used for killing salmonella in
ground beef is most unlikely to ever do that. It takes a pretty big
accelerator.

None of them can be used on packages of widely different thickness and
contents to reliably kill microorganisms, so quit worrying about shipping
stuff in boxes. OK? They ain't gonna do it any time soon. Letters, maybe.
Boxes, no.

The morons we elect to office, and the dimwit bureaucrats they like to hire
don't usually know very much physics. They do know they can get away with
extracting more money from you and hiring more underlings if they can scare
the pants off of you. 

Please don't encourage them. Perhaps a bit more tongue-in-cheek humor (like my
.sig) is exactly what they deserve. (^_^; * 

Wright
_____________
* Japanese smiley. Same as (^_^) but sweating.

-- 
Wright Huntley 510 612-1467 - 879 Clara Drive, Palo Alto CA  94303

Bush just signed the Civil Liberty Elimination Act (the terrorists'
fondest wish), so:

                 For FBI Carnivore Use Only:
Anthrax can be spread by explosion from ammonium nitrate and
diesel fuel. Nuclear devices not required. Smallpox is different.
See E-Bay for ceramic knives that don't trigger metal detectors, too.
They are great for stopping hijackers, cold. Don't tell them, OK?