12
4 Operation of the DLD
Mistakes, which lead to complete wrong measurement results, can happen very easily
while taking the detector to operation. Therefore it is strongly advised to read the
following sections completely before taking the detector to operation and to strictly
follow all given advices within it.
All operation voltages for the detector are given within the detectors specification sheet.
Due to gain degradation it will become necessary to increase the operation voltage from
time to time. Please refer to
for detailed information.
4.1 “Start Up” Procedure for First Time Operation
Note
4.1.1 “Start Up“ Procedure
Follow this procedure when taken the detector to operation the first time and after every venting.
• Finish the complete cabling as described in
and as described in the manual of the HV Power
Supply.
• Turn on the TDC.
• Start your end-user software (e.g. GUI software) and within this software the rate meter, if available. For
details see your end-user software manual.
• Be sure, that the vacuum pressure at the detector is remarkably below 1E-6mbar, otherwise the micro
channel 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.
Ion gauges and ion pump are both sources for electrons and ions. Ion pumps can also
be a source for X-rays. They can produce so many particles/X-rays that the detector is in
a complete overload, even when they are not facing the detector directly. This will wear
out the MCPs very fast. Turn off ion pumps and ion gauges before turning on the high
voltage of the detector.
• 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
Figure 3
.
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).
DLD8080 R4.30 & R4.31 Manual | Surface Concept GmbH
