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1-Channel MCP Detector MCPD25 Manual
1-Channel MCP Detector MCPD25 Manual | Surface Concept GmbH
4.1.2 Dark Count Rate Measurement
• Check the detector output by means of any electronics and software or with an oscilloscope where the
input is terminated with 50Ohm.
• The dark count rate without any source should be as given in the specification sheet.
4.1.3 Standard Detector Measurement
• After finishing the dark count rate measurement with a satisfying result, you may now start carefully
with an electron or light source observing the detector output.
Turn off the high voltage before performing any changes of the cabling.
Use this procedure for all later operation when the detector has already been operated in vacuum
before and has not been vented in between.
• Finish the complete cabling as described in
.
• Be sure, that the vacuum pressure at the detector is remarkably below 1E-6mbar, otherwise the
microchannel plates might be damaged by a local discharging (in general: the lower the pressure, the
longer the lifetime of the MCPs).
• Turn off all sources for electrons, ions, light or X-rays that might hit the detector.
• Turn up the high voltage carefully and stepwise within 2 - 3 minutes to the operation voltage. The
starting operation voltage is specified in the specification sheet of the detector.
• Watch the vacuum pressure while increasing the high voltage; turn the voltages back, if an unusual
increase is observed in the pressure (indicator for high voltage sparking).
4.2 Standard Operation Procedure
4.2.1 Operation with MCP Front Side terminated to GROUND
High voltage sparks may seriously damage the detector anode or the MCPs. Observe the
chamber pressure carefully every time the high voltage is turned on. Switch off the high
voltage immediately in case of a temporary pressure rise by an order of magnitude or
more. This indicates high voltage sparking.
