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DLD4040 R2.55 & R3.54 Manual | Surface Concept GmbH
• Turn on the high voltage carefully. The voltage increase should not exceed 400V per minute. A schematic
sketch on how to ramp the voltages during the “Start-Up” procedure is given in
.
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).
High voltage sparks may seriously damage the detector anode/meander 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.
If sparking occurs, turn down the high voltage immediately and wait some time (up to
5 min.). Start the “Start-Up” procedure again with an increased ramp time. Turn off the
high voltage completely, stop the procedure and call SURFACE CONCEPT for further
assistance, if it is not possible to reach the operation voltage without sparking.
Figure 3: Schematic sketch on voltage ramping during “Start-Up” procedure.
The detector starting operation voltage for “MCP-B” is given in the specification sheet.
The voltage for “U_DLD” is fixed to “MCP-B” + 400V, when using the Surface Concept
HV Power Supply. It cannot be changed by the user and is therefore always increasing/
decreasing together with the voltage for “MCP-B” .
The voltage for “MCP-B” is always given in reference to the MCP front voltage “MCP-F”
(which corresponds to the external reference voltage of the Surface Concept HV Power
Supply). Depending on the detector setup the voltage difference between “U_DLD” and
“MCP-B” can be different than 400V.
Note
