|alpha particles emitted from a radioactive isotope|
|ionizing radiation consisting of a stream of alpha particles|
alpha ray n.
A stream of alpha particles or a single high-speed alpha particle.
A stream of alpha particles.
Particles sent out by some radioactive nuclei, each particle consisting of two protons and two neutrons bound together. Alpha particles carry a positive charge. (See beta radiation and gamma radiation.)
Note: Alpha radiation, unlike gamma radiation, has low penetrating power; it can be stopped by clothing.