bremsstrahlung

noun

brems·​strah·​lung ˈbrem(p)-ˌshträ-ləŋ 

: the electromagnetic radiation produced by the sudden deceleration of a charged particle in an intense electric field (as of an atomic nucleus)

also : the process that produces such radiation

Word History

Etymology

German, literally, decelerated radiation

First Known Use

1935, in the meaning defined above