At present, there are two kinds of image intensifiers, one for super Gen.2 image intensifier ,The other is The Gen.3 image intensifier, the super Gen.2 image intensifier, represented by the French company Photonis. The Gen.3 image intensifiers is represented by the American ITT company (now part of Elbit).
There are many similarities in these two kinds of tubes .The shape, weight, power consumption and interface dimensions of the two image intensifiers are identical. Moreover, the two kinds of image intensifiers use the same set of parameters to describe their performance, and most of the parameters, such as the limit resolution, gain, signal to noise ratio, etc.
If only from the literal understanding of “generation,” since it is the difference between “generation,” the main performance parameters of the super Gen.2 and the Gen.3 of image intensifiers should be different. And the lower generation image intensifier must be replaced by the higher generation image intensifier, that is, the super Gen.2 image intensifier must be replaced by the Gen.3 image intensifier, but the actual situation is not so.
The first Gen.3 of image intensifiers originated in the United States and began mass production in 1985. The super Gen.2 image intensifier originated in France and began mass production in 1990, so far, the super Gen.2 and the Gen.3 image intensifier tubes have been developed for 32 years. In the past 32 years, the Gen.2 Image Intensifier and the Gen.3 image intensifier have been showed a state of parallel development, and from the current situation, there is no sign that the super Gen.2 image intensifier is replaced by the Gen.3 image intensifier. Although the super Gen.2 image intensifier and the Gen.3 image intensifier have little difference in performance . In fact , The super Gen.2and Gen.3 image intensifier are two different technologies, the difference or comparison is in its cathode.The Gen.3 has a GaAs photo cathode,so the cathode sensitivity of the third generation tube is higher than the the super Gen.2 tubes.However the cathode of the Gen.3 is easily destroyed by the positive ions generated by the ionization of the channel plate, and the life is thus shortened, Beside MCP of Gen.3 is plated with an anti-ion anti-break film,because of which , the resolution is to some extent sacrificed,and the noise become larger.
