Positron emission

Encyclopedia : P : PO : POS : Positron emission

Nuclear processes
Radioactive decay processes
Alpha decay
Beta decay
Cluster decay
Double beta decay
Double electron capture
Electron capture
Gamma radiation
Internal conversion
Isomeric transition
Neutron emission
Positron emission
Proton emission
Spontaneous fission
Nucleosynthesis
Neutron Capture
* The R-process
* The S-process
Proton capture:
* The P-process
* The Rp-process
Spallation

Nuclear processes
Radioactive decay processes Alpha decay Beta decay Cluster decay Double beta decay Double electron capture Electron capture Gamma radiation Internal conversion Isomeric transition Neutron emission Positron emission Proton emission Spontaneous fission Nucleosynthesis Neutron Capture * The R-process * The S-process Proton capture: * The P-process * The Rp-process Spallation

Positron emission is a type of beta decay, sometimes referred to as "beta plus" (β⁺). In beta plus decay, a proton is converted to a neutron via the weak nuclear force and a beta plus particle (a positron) and a neutrino are emitted. Isotopes which emit positrons include Carbon-11, Nitrogen-13, Oxygen-15 and Fluorine-18; for example:

[^\hbox\;\to\;^\hbox\;+\;e^+\;+\;\nu_e.]

These isotopes are used in positron emission tomography, a technique used for medical imaging.

Electron capture is a competing decay mode in this process and is energetically favoured, but as the energy difference goes up so does the branching ratio towards positron emission.

Positron emission

See also