A two-dimensional
radiation detector in which the electron image produced by a photo-emitting surface, usually a photocathode,
is focused in the plane of a defining aperture. Magnetic or electric fields scan this
image across the defining aperture.
Source:
PAC, 1995, 67, 1745
(Nomenclature, symbols, units and their usage in spectrochemical analysis-XI. Detection
of radiation (IUPAC Recommendations 1995))
on page 1756