the electromagnetic radiation given off by a high-energy particle, as an electron, when suddenly accelerated or retarded by an electric field or by another charged particle, as an atomic nucleus
See bremsstrahlung in American Heritage Dictionary 4
(brĕmˈshträˌləng)
noun
The electromagnetic radiation produced by a change in the velocity of an electrically charged subatomic particle, such as an electron, as when it collides with another object.