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Figure 7: Example of a) a partial overload and b) a heavy (global) overload.
It is easy to mistake a massive global overload for no signal at all. To distinguish between
these two, check the pressure. A pressure increase indicates an overload.
Note
The DLD has been calibrated for an optimized MCP voltage and it is strongly advised to use this optimized
voltage value for operation. It is given in the specification sheet. A change of the MCP voltage can lead
to artifacts within the images (see
). The MCP voltage should only be increased to compensate a
decrease in amplification of the MCP stack do to degradation. MCPs degradation is recognizable by a slow
permanent decrease of the count rate and happens either due to overloads or due to the normal behavior
in the burn-in phase. In such a case a new detector working voltage should be determined by making a
detector voltage scan or in the worst case: the MCPs must be replaced. For further detailed information on
MCP degradation and detector working voltages see
Figure 8: Example of a) an overvoltage on the MCPs and b) an undervoltage at high count rates.
DLD8080 R4.30 & R4.31 Manual | Surface Concept GmbH
