In this device, photons are detected by a photocathode similar to that in an image intensifier.    From Wordnik.com. Reference

In vidicons, the photosensitive surface stores charge rather than liberating electrons as in a photocathode.    From Wordnik.com. Reference

They have an input photocathode followed by a micro-channel plate electron multiplier and a phosphorescent output screen.    From Wordnik.com. Reference

Low levels of ambient light pass through a photocathode that converts the light photons to electrons, then amplifies them.    From Wordnik.com.  [Defense Industry Daily] Reference

Night vision equipment gathers light and then directs light into the photocathode tube which can convert the photons to electrons.    From Wordnik.com.  [Best Syndication -] Reference

Requiring over 460 manufacturing steps, the Generation III intensifier is typically characterized by a gallium arsenide (GaAs) photocathode.    From Wordnik.com.  [Defense Industry Daily] Reference

The photon sensitivity of the GaAs photocathode extends into the near-infrared region, where night sky illumination and contrast ratios are highest.    From Wordnik.com.  [Defense Industry Daily] Reference

First, an automatic gated power supply system regulates the photocathode voltage, allowing the device to adapt instantaneously to changing light conditions.    From Wordnik.com.  [Defense Industry Daily] Reference

Generally, a reduction of the gain of the intensification stage is employed to limit the noise although intensified CCD cameras are available with a cooled photocathode.    From Wordnik.com. Reference

The output from the metal channel dynode chain is a current proportional to the number of photons striking the photocathode and to the voltage drops along the dynode channel.    From Wordnik.com. Reference

The contribution of these components to the noise created by the statistical nature of the photon flux depends on the gain of the device and the temperature of the photocathode.    From Wordnik.com. Reference

Timing and synchronizing the many components of an NGLS, including its photocathode laser, is a problem facing not just light-source designers but other accelerator designers as well.    From Wordnik.com.  [PhysOrg.com - latest science and technology news stories] Reference

These devices respond when photons impinge on a photocathode and liberate electrons that are accelerated toward an electron multiplier composed of a series of curved plates, known as dynodes.    From Wordnik.com. Reference

Thermal noise from the photocathode as well as electron multiplication noise from the microchannel plate reduce the signal-to-noise in an intensified CCD camera to below that of a slow-scan CCD.    From Wordnik.com. Reference

The photocathode in the latest generation of these devices, while similar to that in photomultiplier tubes, has a higher quantum efficiency (up to 50 percent) in the blue-green end of the spectrum.    From Wordnik.com. Reference

The number of collectable photoelectrons depends on light collection efficiency, which depends on the geometry of the detector, and from the quantum efficiency of the photocathode (usually about 20%).    From Wordnik.com.  [Scientific Blogging] Reference

The advantages of this device over a cooled, slow-scan CCD are the additional gain and accompanying speed; the main disadvantages are the lower quantum efficiency of the photocathode and diminished dynamic range.    From Wordnik.com. Reference

Spectral sensitivity depends on the chemical composition of the photocathode; the best devices often incorporate gallium-arsenide and are sensitive to ultraviolet, visible, and infrared light in the wavelength range from 300 to 850 nanometers (Figure 3).    From Wordnik.com. Reference

Sealed to an input window that minimizes veiling glare, the photocathode generates an electron current which is proximity focused onto a phosphor screen, where the electron energy is converted into green light that can then be relayed to the eye or sensor through an output window.    From Wordnik.com.  [Defense Industry Daily] Reference

Two of the curves (the lower curves in Figure 3) were generated with PMTs having photocathode compositions utilizing either gallium-arsenide-phosphide (Ga-AS-P) or gallium-arsenide (Ga-As) alloys, while the third curve represents the response of a silicon photodiode with a ultraviolet-transparent window.    From Wordnik.com. Reference