ionizing radiation

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun High-energy radiation capable of producing ionization in substances through which it passes. It includes nonparticulate radiation, such as x-rays, and radiation produced by energetic charged particles, such as alpha and beta rays, and by neutrons, as from a nuclear reaction.

from the GNU version of the Collaborative International Dictionary of English.

• noun rays of rapidly moving subatomic particles, x-reys, or gamma rays, sufficiently energetic to cause ionization when absorbed by matter.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun High-energy radiation that is capable of causing ionization in substances through which it passes; also includes high-energy particles.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun high-energy radiation capable of producing ionization in substances through which it passes