Assertion: ion's electron | /r/HasProperty | ejected at relativistic speeds
Facets:
value: usually
type: TEMPORAL
value: not always)
type: TEMPORAL
Source sentences:
text: The first two ionizing sources to be recognized were given special names used today: Helium nuclei ejected from atomic nuclei are called alpha particles, and electrons ejected usually (but not always) at relativistic speeds, are called beta particles.