Do your tubes work?

Abex (UK) takes pride in offering fully tested tubes.  Our 100% testing and screening process is designed to weed-out any tubes that fall below a useful level of performance, while grading the others according to a simple scale - "A", "B", or "C".  Any tube falling below Grade C are clearly identified as non-functional.

Are "Grade C" tubes of any use?

Grade "C" is the lowest level of performance which we deem useful for recreational (non-professional) purposes.  This should not be interpreted as "useless", which they certainly are not.  Any tubes which fail our strict test programme are sold for display/educational purposes only, and will be clearly identified as "non-functional".  A grade "C" tube is ideal for wildlife at an entry-level price.

Are your tubes guaranteed?

If you purchase one of our graded tubes, it will be covered by our standard 30 day warranty.  We will refund/replace at our discretion if we are happy that the tube has not been abused or misused in any way.  Intensifier tubes are very sensitive to optical damage, which is why our testing and screening process is complemented by comprehensive test data logging to assist in the unlikely event of problems occurring.

Gen 1, 2 or 3?

Image intensifier tubes are classified by "generation".  "Gen 2" differs from "Gen 1" by the insertion of a "Micro Channel Plate" just in front of the phosphor screen.  This plate boosts the gain of the tube, typically by 100's or even 1000's, and is possibly the most important technical enhancement to be seen since image intensifiers were invented.  "Gen 3" technology utilises a different material (Gallium Arsenide) in the photocathode, which principally affects the spectral response.  The resulting enhanced performance at infra-red wavelengths is important for military applications, but of little benefit otherwise.

Are Gen 1 tubes less sensitive?

No, they can be more sensitive than Gen 2&3.  This is because the micro channel plate used in Gen 2&3 tubes is a mesh of fine holes, and some electrons emitted by the photocathode will be lost when they strike the boundary between holes.  The loss can be between 10% and 20%.  The terms "sensitivity" and "gain" must be considered separately.  In most cases, Gen 2 tubes will have much higher gain and deliver superior performance, even though they may be slightly less sensitive.

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