All optics and optronics
This group holds the image intensifier tubes and assemblies at the heart of the night vision sights, goggles and periscopes in the catalogue. Formats run from 18 mm Gen II+ and Gen III tubes, inverting and non-inverting, such as HD 2100, HD 2102 and HD 1520A, through the 25 mm HD 1400 and HD 1400 E10 assemblies, to the 40 mm HD 1430 single-stage tube and the Gen I cascade tubes HD 1211A, HD 1270 and HD 25/25. Each entry lists photocathode sensitivity, luminous gain, limiting resolution, MTF and MTTF as published.
Gen I three-stage electrostatically focused image intensifier with 18 mm S25 photocathode and aluminized phosphor screen.
Gen I two-stage electrostatically focused image intensifier tube with S25 photocathode, aluminized phosphor screen and automatic brightness control.
25 mm image intensifier assembly with microchannel electron multiplier, extended red S25 photocathode, ABC and bright source protection.
25 mm image intensifier assembly variant with aluminized phosphor screen, external gain control circuit, ABC and bright source protection.
Single stage electrostatically focused image intensifier with 40 mm useful diameter for the AN/VSG-2 tank system, powered from an external high voltage supply.
18 mm inverting Gen III image intensifier tube with GaAs extended red photocathode, MCP amplifier, ABC and bright source protection.
18 mm inverting Gen II+ image intensifier tube with S25 extended red photocathode on glass input window, MCP amplifier and fibre optic screen.
18 mm non-inverting Gen II+ image intensifier tube with S25 extended red photocathode, MCP amplifier and fibre optic phosphor screen.
Gen I three-stage electrostatically focused image intensifier with 23 mm photocathode, three image modules and automatic brightness control.
Tenders normally fix the format (18 mm, 25 mm or 40 mm), the generation, whether the tube is inverting or non-inverting, and minimum values for photocathode sensitivity in uA/lm, limiting resolution in lp/mm, signal-to-noise ratio and MTTF in hours. Where a figure of merit is required it is the product of resolution and signal-to-noise ratio. Automatic brightness control and bright source protection are specified as functions rather than numbers. Quoting the equivalent label where one exists makes cross-reference to legacy documentation straightforward.
HD 2100 and HD 2102 are 18 mm Gen II+ tubes with an S25 extended red photocathode, the first inverting and the second non-inverting. HD 1520A is the 18 mm Gen III tube with a GaAs photocathode and a 10000 hour MTTF. HD 1400 and HD 1400 E10 are 25 mm assemblies, the E10 adding an external gain control circuit. HD 1430 is a 40 mm single-stage tube for the AN/VSG-2 tank system, while HD 1211A, HD 1270 and HD 25/25 are Gen I cascade tubes, three-stage except the two-stage HD 1270.
An inverting tube such as HD 2100 turns the image upside down internally, so the host device's optics are designed to correct it, while a non-inverting tube such as HD 2102 delivers an upright image. The two are not interchangeable in a given housing, so the tender should state which type the equipment requires.
The NNS, RIS and TKN-1MS entries list HD 2100 or HD 1520 tubes, TPN-1MS uses HD 2100, TKN-3B and TVNE-4VMS use HD 1520, and the M66 A2 MS and TVN-2MS driver periscopes list the HD 1400 M variant. Tube supply for these devices can therefore be aligned with the same designations.
