Micro-channel plate CRT: Difference between revisions

Micro-channel plate CRT (view source)

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-The micro-channel plate (MCP) is an extra element that can be included in a [[CRT]] to improve the brightness of the
+The micro-channel plate (MCP) is form of secondary electron multiplier that can be included in a [[CRT]] to improve the brightness of the
-trace at high sweep rates.  Typically it sits directly behind the face of the CRT.
+trace, which is needed particularly at high sweep rates.  Typically it sits directly behind the face of the CRT.  It requires its own bias voltage.
-It requires its own bias voltage.
-MCPs have finite life and careful biasing is necessary to get the full life.
+The electron beam passes through the deflection plates before it hits the micro-channel plate, which consists of parallel channels
+offset at a slight angle to the beam. The inside walls of these channels are coated with resistive material, with an acceleration voltage
+on the order of 1 kV applied between back and front of the plate. Electrons entering a channel hit the wall where they initiate a cascade
+of secondary electron emission like in a photomultiplier. At the exit of the channels, a final acceleration voltage propels the beam across
+a small gap toward the CRT's phosphor coating.  In a typical MCP CRT like the [[T7100]], the channels have 25 μm diameters.
+MCP amplification deteriorates in proportion to total charge passed per channel or unit of area, making them
+particularly prone to a form of burn-in.
+Careful biasing along with beam current/time limiting mechanisms are necessary to achieve the full life time.
+The MCP enables an improved system bandwidth overall.
 MCP tubes are used in the following Tektronix products: