(Submitted February 09, 1998)
I know that gamma rays were discovered shortly after alpha and beta particles,
but who is given credit for the discovery?
Paul Villard, a French physicist, is credited with discovering gamma
rays. Most sources put this in 1900, although I've seen a few sources
use 1898. Villard recognized them as different from X-rays (discovered
in 1896 by Roentgen) because the gamma rays had a much greater penetrating
depth. It wasn't until 1914 that Rutherford showed that they were
a form of light with a much shorter wavelength than X-rays.
A good web site on the history of the discovery of radiation, written by
Michael Fowler at University of Virginia, is:
for Ask an Astrophysicist