[labnetwork] SEM Liner Tube Voltage Issue

[Liu, Bangzhi]

There is a special tool you can get from Zeiss to pull the liner tube out from the bottom once you remove the end cap. You can order it directly from Zeiss.

One thing simple you can try is vacuuming the column from the bottom if you suspect there is a particle flying into the column, which happened occasionally in our case. A good vacuuming could suck it out.

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From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Nicki Shaw <nashaw at uwaterloo.ca>
Sent: Monday, March 3, 2025 5:08:04 PM
To: labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
Subject: [labnetwork] SEM Liner Tube Voltage Issue

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Hello,
We are troubleshooting a SEM column issue on our FIB-SEM following a planned power interruption. In short, any advice regarding the disassembly of a Gemini SEM column or liner tube troubleshooting/maintenance would be greatly appreciated.
The tool in question is a ZEISS Auriga 40, and we have observed the following:

  *
The SEM image is significantly rotated relative to the expected alignment, despite the scan rotation being off.
  *
The Inlens detector does not get a signal, but the SESI detector gets a signal with some apertures. The emission view shows that the apertures are significantly misaligned, despite no manual changes being performed.
  *
The image rotation improves as SEM voltage is increased, becoming nearly correct at 21 kV—at which point the liner tube shuts off.

During troubleshooting, we measured the liner tube voltage:

  *   When running the liner without connecting it to the column (with a resistor in place to draw current), the voltage ramps normally.
  *   When the liner is connected to the column, the voltage plateaus at 600–700 V instead of reaching the expected 8000 V.

We have checked:

  *   The liner tube cable and relay box connections.
  *   The power module and associated lens control boards.

Given these observations, it seems likely that there is a voltage leak inside the column affecting the liner tube voltage. Has anyone encountered a similar issue, or can provide insight into further troubleshooting steps? We are considering opening the column to check for a short but have not attempted any disassembly other than replacing the filament.
Any advice would be greatly appreciated!
All the best,
Nicki
Senior Facility Microscopist
Quantum-Nano Fabrication and Characterization Facility (QNFCF)
200 University Ave W | Waterloo, Ontario | N2L 3G1
Office: QNC 1611
P: +1 519-888-4567 ext. 42022
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