Nikon 9350 manual

photocathode. This dim light consists of energy in both the visible and near-infrared portions of the electromagnetic spectrum.

2.When the light impinges on the photocathode (the light sensitive portion of the image intensifier) electrons are emitted with amplitude determined by the photocathode's spectral responsivity and the amount of light energy. Because of the image intensifier's internal electrical field, these electrons are accelerated toward the microchannel plate assembly, the image intensifier's amplification mechanism.

3.The microchannel plate is a glass plate with millions of tiny closely-spaced channels bored through it. The plate is coated with a special substance that produces secondary electron emission when impinged by an electron. Due to the potential difference across the plate, an incident electron enters a channel and frees other electrons from the channel wall. These electrons are accelerated along the channel in turn striking the channel surface again and again, giving rise to more and more electrons. Eventually this cascade process yields a cloud of several thousand electrons, which emerge from the rear of the plate.

4.Electrons exiting the microchannel plate strike a phosphor that emits light proportional to the amount of electrons hitting it. The image is green because the selected phosphor glows green when charged. The green color is selected because the human eye can differentiate more shades of green than any other color.

5.Because the image is inverted, a fiber optic "twister" is used to rotate the image 180°.

6.A special relay optic focuses the image properly to match the image plane requirements of video and 35mm SLR cameras.

Image intensifiers exhibit several key features designed to optimize their use, as follows:

Automatic Brightness Control (ABC): An electronic feature that automatically reduces voltages to the MCP to keep the image intensifier’s brightness within optimal limits and protect the image intensifier. The effect of this can be seen when rapidly changing from low-light to high-light conditions; the image gets brighter and then after a momentary delay, suddenly dims to a constant level.

Bright-Source Protection (BSP): An electronic function that reduces the voltage to the photocathode when the image intensifier is exposed to bright light sources such as room lights or car lights. It protects the image intensifier from damage and enhances its life.

Equivalent Background Illumination (EBI): This describes the amount of light you see from the output of the image intensifier when there is no light input. It increases with increasing temperature. EBI is measured in lumens per square centimeters and determines the light level, which equals the image intensifier’s noise level. Below this light level, objects will be masked by EBI. The lower value of EBI, the better.

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