Neutralizer filament replacement procedure

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This post will detail the neutralizer filament replacement procedure for the Physical Electronics (PHI) 04-085 and 04-090 neutralizers that are commonly found on many PHI X-ray photoelectron spectrometers and Static SIMS systems.

Before you can replace the filament you need a new filament. We also recommend having the deflection ceramic on hand, as well, since the deflection ceramic is usually cracked when you remove it as part of the neutralizer filament replacement procedure. The neutralizer ceramic and neutralizer filament are readily available from RBD Instruments dot com.


This procedure assumes that the system has been vented and the neutralizer is on a clean work area. Use clean tools and wear gloves while working on the neutralizer to prevent any oil contamination on the neutralizer parts. Tip: Use UHV aluminum foil to keep the work area clean, and fold up the ends of the aluminum foil to make a tray that will trap any small parts that you may drop during the procedure.  The pictures at the bottom of the post are helpful.

  1. Remove the 4 screws that hold down the exit aperture.
  2. Remove the exit aperture.
  3. Remove the 4 shoulder washer ceramics from the deflection plates.
  4. Lift up the 4 deflection plates and position the wires so that you can remember where they go back to later.
  5. Remove the deflection ceramic. If it is not in broken into pieces you can reuse it.
  6. Lift up the anode aperture and position the wire to the side. There is a groove in the filament housing so it can only go back one way.
  7. Remove the three screws at the bottom of the filament housing. Tip: Scribe the side of the filament housing to help you remember the orientation later.
  8. Remove the filament housing. Note that the anode ceramic will still be inside the filament housing.
  9. Remove the wehnelt cap.
  10. Hold the filament in place and slide the filament connectors down and off of the filament posts.
  11. Remove the filament.
  12. Install the new filament. While holding the filament in place slide the filament connectors on.
  13. Install the wehnelt cap (carefully) over the filament.
  14. Install the filament housing over the wehnelt cap and install then tighten the three screws that hold the filament housing to the neutralizer support base.   Make sure that the tip of the filament is centered in the wehnelt cap.
  15. Install the wehnelt ceramic over the wehnelt cap and center the wehnelt cap within the ceramic. If necessary, loosen the three filament housing screws to adjust the housing position a little bit, and then re-tighten them.
  16. Install the anode aperture ceramic.
  17. Install the deflection ceramic.
  18. Move the deflection plates into position and install the shoulder washer ceramics into the deflection plates.
  19. Place the exit aperture on top and install the screws to hold the exit aperture on top of the shoulder washer ceramics. This can be a little tricky.
  20. With the top screws tightened only slightly, adjust the space between all four deflection plates so that they are even, and tighten the four screws.

Installation is complete! When you burn in the new filament, start out with a low emission value and increase it until the filament is just starting to glow orange. Let the neutralizer outgas in that mode for an hour or so, then slowly bring the filament up to the normal emission setting as needed.

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  1. Pingback: 72-030 Neutralizer Current limit procedure | RBD TechSpot

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