alpha (alpha) particle

(redirected from alpha a particle)

al·pha (α) par·ti·cle

(al'fă pahr'ti-kĕl)
A particle consisting of two neutrons and two protons, with a positive charge (2e+); emitted energetically from the nuclei of unstable isotopes of high atomic number (elements of mass number from 82 up); identical to the helium nucleus.