Emittance may refer to:
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Beam emittance
In accelerator physics, emittance is a property of a charged particle beam. It refers to the area occupied by the beam in a position-and-momentum phase space.
Each particle in a beam can be described by its position and momentum along each of t ...
, the area occupied by a beam in a position-and-momentum phase space
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Radiant emittance, the radiant flux emitted by a surface per unit area
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Thermal emittance, emissivity of a surface
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