20 PI-MAX/PI-MAX2 System Manual Version 5.F
3. Since the voltage at the MCP output is much more positive, most of the electrons
accelerate into the MCP channels and, if they hit the channel walls, will generate
additional electrons, resulting in electron gain. The amount of gain is adjusted by
increasing or decreasing the voltage at the MCP output.
4. When the electrons exit the channels they are further accelerated by a constant high
voltage (5-8 kV) and strike the phosphor coating on the fluorescent screen causing it
to release photons. Because of the MCP gain, there are now many photons for each
photon that struck the photocathode surface.
5. The photons released by the coating are transferred to the surface of the CCD (via
fiberoptic or lens), pass through the input window, and produce charge at the pixels
they strike. Note that fiberoptic coupling is not only the most efficient coupling
possible, but lens-coupling effects such as vignetting are eliminated.
6. Charge accumulates in the pixel wells until the intensifier is gated off (the
photocathode is more positive than the MCP input).
7. At that point, the accumulated charge is shifted to the serial register where it is read
out to an on-chip amplifier that converts the charge to an analog voltage.
8. This voltage is input to the selected analog-to-digital (A/D) converter where it is
digitally encoded. The conversion speed and the quality of the data are dependent on
the A/D selected (High Speed or Low Noise).
9. The digitized information is transmitted from the camera head through the TAXI
cable to the interface card in the host computer where it is stored in RAM.
10. The application software retrieves the information from RAM, processes it, displays
it, and/or stores it to a file according to user-defined settings.
Safety Information
Safety Related Symbols Used in This Manual
Caution! The use of this symbol on equipment indicates that one or
more nearby items should not be operated without first consulting the
manual. The same symbol appears in the manual adjacent to the text
that discusses the hardware item(s) in question.
Caution! Risk of electric shock! The use of this symbol on
equipment indicates that one or more nearby items pose an electric
shock hazard and should be regarded as potentially dangerous. This
same symbol appears in the manual adjacent to the text that discusses
the hardware item(s) in question.
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