Three New Videos from Photonis

Photonis has released new videos describing the latest improvements in its image intensifiers.  

A little background might be useful to those with little exposure to image intensifiers.

First, Photonis itself. Those of you who are interested in the whole complex story can find it here. The original Photonis was a renamed spinoff of Philips that subsequently acquired a few other companies including Burle, the renamed spinoff of RCA's vacuum tube operation. Recently, the Photonis Group renamed itself Exosens but still uses Photonis as the brand for its image intensifiers.

Image intensifiers are vacuum tubes that have at one end a surface that emits electrons on receipt of photons, some sort of acceleration and electron multiplication mechanism and a phosphor at the other end to produce a brighter visible image. As new developments have been applied to intensifiers, various generations have been assigned.

Gen 0 - See this (somewhat irreverent) link. (Not real, of course.) Sometimes the first low-gain tubes are called Gen 0.

Gen 1 - Light hitting an alkali photocathode produces electrons that are accelerated and electrostatically focused by a metal cone on to a curved phosphor. These invert the image, which is reverted by the optics - 1930s - 1960s.

Gen 2 - Proximity-focused electrons from the photocathode hit a microchannel plate in which they are multiplied. The electron output is proximity-focused on a flat phosphor. Some of these still have the focusing cone to provide image inversion. 1970s

Gen 3 - The alkali photocathode is replaced by a cesium-coated gallium arsenide membrane. 1970s-1990s

Gen 4 - Photocathode improvements of various types and, typically, electronic gating. Strictly speaking, these are still Gen 3. 2000s+

The videos showing tubes Photonis characterizes as Gen 4+:

1 - Demonstration of electronic gating

2 - Demonstration of performance

3 - Demonstration of halo improvements