A vacuum tube containing a photosensitive area, or target, and an electron gun to
read the signal from the target. The silicon target consists of a two-dimensional
array of Si-photodiodes having a common
cathode and isolated anodes.
Irradiation of the target causes the production of electron-hole pairs which, by recombination,
leads to a depletion of the surface charge.
Source:
PAC, 1995, 67, 1745
(Nomenclature, symbols, units and their usage in spectrochemical analysis-XI. Detection
of radiation (IUPAC Recommendations 1995))
on page 1757