Grading of Intensifier tubes

Image intensifiers are easily damaged by exposure to bright light.  The damage which results from such exposure is not repairable.

The most common type of defect seen in ex-military night scopes is the small dark spots that result from the use of battlefield laser range-finding equipment.  These spots are permanent "burns" in the photocathode, but are of little consequence to the recreational user.  The majority of the image will still be crisp and well focused, with little or no loss of gain or sensitivity.  If there are a large number of spots, or if the individual spots are very large, they can be quite obtrusive and render the tube unsuitable for demanding applications.  However, for many applications, even relatively serious burns do not render the tube useless.  Eventually, accumulated damage may degrade the tube to a point where it is considered of no further use.

The second type of defect which can occur with all types of intensifier tubes a gradual loss of sensitivity with use.  This is rarely seen with ex-military units, which are generally "retired" as a result of range-finder burns long before they get chance to "wear out".

We sell ex-military scopes loosely described as "new" or "used", which refers to the condition of the housing, not the condition of the tube.  We test every unit to ensure satisfactory performance, which should be at least meeting the standard of Grade "B".

We also sell bare tubes graded as "A", "B", or "C".  Grade "A" is basically the level of performance which could be expected of a new tube.  We consider "Grade C" to be the worst level of performance acceptable for general or recreational purposes.