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Gallium arsenide
The photosensitive material used in the photocathodes of Gen 3 intensifier tubes. It is far more sensitive than the multialkali cathodes in Gen 2 tubes.
Gen 2
NVIS intensifier tube technology that uses a multialkali photocathode and multichannel plate (MCP) intensifier. Gen 2 NVIS is now only used for ground operations.
Gen 3
NVIS intensifier tube technology that uses a gallium arsenide photocathode and multichannel plate (MCP) intensifier. Gen 3 tubes are more sensitive than Gen 2 and are used in NVIS for aviation.
Image intensifier tube
See Intensifier tube.
Infrared (IR)
Electromagnetic energy outside the visible band with wavelengths between 700 and 1,500 nanometers.
Intensifier tube
A vacuum tube device that converts visible and infrared light to electrons, multiplies the electrons, and then converts them to a visible image on a phosphor screen.
Luminance
A unit of lighting measurement identical to radiance except that it is based on the visual (photopic) brightness of a light source rather than the total brightness. It is expressed in lumens (rather than watts) per steradian per surface unit. A commonly used alternative unit is the footlambert (fL). See Radiance below.
Microchannel plate (MCP)
An MCP is a thin disk of tiny glass tubes or microchannels (about 10 microns in diameter) fused together like a wafer. Inside the channels are coated with an electron emission film connected to input and output electrodes. An electron striking the input side of a channel causes a cascade of electron emissions, multiplying the electron output. Tubes with an MCP intensifier (Gen 2 and 3) are often called wafer tubes.
MIL-L-85762A
A tri-service specification that defined NVIS-compatible illumination for aircraft interiors. Superseded in February 2001 by MIL-STD-3009 (see below).
MIL-STD-3009
The current version of the NVIS-compatible lighting standard, effective February 2001. As stated in its Foreword, “This new document was derived from MIL-L-85762A as a way to preserve this widely accepted standard definition, and to comply with the Perry directive. In compliance with the Perry directive, this document no longer contains the lighting system design requirements that were in MIL-L-85762; it now deals only with interface and performance requirements.” To download a complete copy of MIL-STD-3009 in PDF format, click here (584 KB).
Minus-blue filter
A filter that cuts off any visible light below a certain wavelength. See Class A and Class B, above.
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