There are thermal optics of different shapes and sizes and four generations. Gen 0 and Gen 1 are based on creating an electrostatic field and accelerating photons to intensify. They distort the image around the edges, and while Gen 0 always needs IR, Gen 1 was the first to amplify residual light, albeit little. Super Gen 1+ improves performance and corrects distortion somewhat. It is the best option today. A common characteristic is that they stay on for a while after turning them off because they hold some charge.
The processing in the Gen 2 and Gen 3 Thermal Optics
Gen 2 and Gen 3 thermal opticsturn off immediately, are much smaller, and consume much less current. Both use a microchannel plate (MCP) to improve gain and resolution, and Gen 3 adds an ion barrier to extend tube life.
Gen 1 and Gen 2 photocathodes are both the same (Tri-Alkaline), while Gen 3 uses a Gallium Arsenide photocathode, up to three times more sensitive. For night vision device storage, this comes perfect.
The fake Claims
Be careful with thermal optics claiming to be ITT (US) Gen 2+ because only Gen 3 thermal opticshave been made in the United States for ten years. In all probability, they will come from liquidation balances of the American army. Hopefully, they will have spent years on an unused shelf but with outdated technology. At worst, they will have many hours of use and minimal life.
Although the third generation is the most sensitive, its use in residual light situations offers a whitish, low-contrast image. They do not contribute anything to cheaper equipment. Only in remote rural areas are they used to the full.
The latest development is self-gating thermal optics. They are designed to reduce reflections and glare when there are spotlights or when moving from dark to bright areas. They are not intended for use in continuous daylight.
In night vision, it is more accurate than in many other products that you get what you pay for. The performance improvement is spectacular as you go up the scale of the intensifier thermal optics, but the price increase is also stunning.
Generation 0 – Typically uses an S-1 photocathode with a response peak in the green-blue zone and 60 µA / lm photosensitivity. They are based on the creation of a strong electrostatic field to accelerate the electrons. This type of tube distorts the image a lot and always needs the help of emitted IR light.
The Best Use of the Gen 1
Generation 1 – Typically uses an S-10 or S-20 photocathode with photosensitivity of 120-200 µA / lm. They are based on the creation of a strong electrostatic field to accelerate the electrons. Being much more sensitive, they are the first ones who do not always need IR help (they see something more than the naked eye).
Gen 1s has high-voltage power supplies, edge distortion, and decent low-light behaviour. The tube holds some charge and is still visible for a few seconds after turning it off. The tube’s gain is usually 100-500x with a resolution of 25-30 lp / mm, although some manufacturers put higher figures. They have high consumption, and it is common to see regular spots. Thermal optics made and Belarus account for 95% of the market. The average service life is about 1,000 hours.