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Thermo Fisher Scientific

No Beam after opening column valve


No beam after opening column valve


Titan G2 60-300


These are possible resolutions for the issue:

  • Replace valve block


These are possible causes for the issue:

  • Valve block defect


  1. Beam cannot be found after user normal operation, FEG emission is 44uA (SFEG)
  2. Reloaded alignment file and rechecked gun tilt and gun shift
  3. Inserted Oxford detector and counts is about 300, so no beam reaching detector
  4. All the LEDs on IPB is on
  • The IPB has 9 green LEDS (H1 to H9) and all of them must be lit to indicate that all safeties are present and not activated. In that case the lenses can be switched on.
  • IPB H10 and H11 indicate that the Beam deflection safeties are present and not activated. H10 is Vac or Vcp, H11 is Goniometer X ray safety.
  1. In blanker page, found beam is not blocked when the holder is inserted with valve opening
  2. All apertures are set to the biggest size, and its position were verified per 4022 190 61349, moved C2 AAS all the way and cannot find the beam
  3. Corrector PC shows no issue
  4. Fianally found that during opening/closing vac, the pneumatics sounds abnormal. Vc is actually not opened and therefore blocked the beam

WI 4022 190 61349
WI 103649


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