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Re: Radiation lesson

> From: Wright Huntley <jwwiii at pacbell_net>
> Subject: 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),

	The shorter the wavelength, the more the ionisation, because each
photon has more energy.  This refers to electromagnetic radiation.

> Particle bombardment with neutrons and electrons (alpha and beta "rays") 

	Alpha particles are helium nuclei.  Neutrons aren't ionising
themselves, _but_...

> penetrate some materials and can cause residual radioactivity if they actually
> split atoms into unstable isotopes.

	Neutrons can cause fission of uranium, thorium and plutonium (if you
hit the right isotope).  They are readily absorbed by _lots_ of other elements,
causing the formation of a higher mass number isotope of the same element.
_That_ may well be unstable (usually a beta emitter).  The phenomenon is
very useful for analytical purposes - I've used it.

> The kind used for killing salmonella in
> ground beef is most unlikely to ever do that. It takes a pretty big
> accelerator.

	Usually pretty hard gamma rays from very high energy electrons.
Anything that kills bacteria is going to finish off the plants, I think.

Paul Sears        Ottawa, Canada