Gamma rays

Paul Ulrich Villard discovered gamma rays while studying uranium radiation. These rays were even more pentrating than x-rays and characterized by their short wavelength, distinguishing them from alpha and beta rays.
 Paul Ulrich Villard France 1900 Gamma rays

Paul Ulrich Villard discovered gamma rays while studying uranium radiation. These rays were even more pentrating than x-rays and characterized by their short wavelength, distinguishing them from alpha and beta rays.