The image contrast of an 9″ image intensifier is to place a circular X-ray shielded lead plate equal to 10% of the effective area of the input plane at the center of the 9″ image intensifier. The ratio of the maximum brightness of the part without the lead plate screen to the brightness of the part covered by the line plate is observed from the output screen. This is called image contrast.
Therefore, the greater the image contrast of the 9″ image intensifier, the better the image contrast, the better the image effect of the 9″ image intensifier, and the quality of the 9″ image intensifier can be guaranteed. The image contrast of the 9″ image intensifier is generally 6:1, 12:1, 15:1 or higher.
The brand of 9″ image intensifier includes Newheek, Thales, Toshiba and so on.