emission (redirected from Positron emission)

emission /emis·sion/ (e-mish´un)

1. discharge (1).

2. an involuntary discharge of semen.

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nocturnal emission  reflex emission of semen during sleep.

positron emission  a form of radioactive decay in which a positron (β+) and neutrino are ejected from the nucleus as a proton is transformed into a neutron. Collision of the positron with an electron causes annihilation of both particles and conversion of their masses into energy in the form of two 0.511 MeV gamma rays.

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e·mis·sion (-mshn)

n.

A discharge of fluid from a living body, usually a seminal discharge.

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emission

[imish′ən]

Etymology: L, emittere, to send out

a discharge or release of something, as a fluid from the body, electronic signals from a radio transmitter, or an alpha or beta particle from an atomic nucleus during radioactive decay.

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emission

a discharge.

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emission

The release of a gas, fluid or solid. See Alpha emission Otoacoustic emission.