Alpha particles (named after and denoted by the first letter in the
Greek alphabet, α) consist of two
protons and two
neutrons bound together into a particle identical to a
helium nucleus; hence, it can be written as He2+ or 42He. They are a highly
ionizing form of
particle radiation, and have low penetration. The
alpha particle mass is 6.644656×10-27 kg, which is equivalent to the energy of 3.72738
GeV. The charge of an alpha particle is equal to +2e, where e is the magnitude of charge on an electron, e=1.602176462x10-19C.
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