Author Archives: Randy

660 Scanning Auger Bake-out procedure

Posted on by
Reply

660 Scanning Auger Bake-out procedure.

This procedure is written for the PHI 660 scanning Auger system but also works for the 600 scanning Auger systems as well.

  1. Ion pumps must be on and the system vacuum should be in the mid to low 10-7 range (or better)..
  2. Make sure that the card rack power supply is OFF. Also make sure that these units are OFF:
  • 20-610 High Voltage Supply
  • 20-622 Gun control
  • 11-065 Ion gun supply
  • Balzers Thermo Valve Control  (gas valve also needs to be closed)
  1. The DIGIII ion gauge control and Boostivac ion pump control  should be ON.
  2. Remove all cables that are above the table top. These include the Auger analyzer, SIMS analyzer (if so equipped), 96A V/F preamp, 1182 or 1120 amplifier discriminator, and the 97 SED preamp.   TIP: Make sure that the cables are labeled as you remove them.
  3. When removing the 97 SED preamp be careful not break the feedthrough pins!  Also when you put it back on after the bake-out make sure it is flush with the flange and then use a flat blade screwdriver to tighten the screws – snug plus 1/8 to 1/4 turn.
  4. Remove the filament cap on the top of the analyzer (3 screws at the base, do not unscrew the cable!).
  5. All of the cables above the table top should now be removed.
  6. Remove the wooden tabletops.
  7. Pull up on the table top switches.  Note that in some cases the switches need to be pulled all the way up, but in other cases they may just need to spring up after the table tops are removed.  If the bake-out timer does not start, check the table top switches.
  8. Wipe off any fingerprints from the system with Isopropanol (work it may, shine it must!).
  9. Cover all of the windows with aluminum foil. Also cover the stage micrometers and any exposed feedthroughs. If you are uncertain – cover it just to be safe.
  10. Place the bakeout blanket over the vacuum chamber. These blankets have fiberglass in them so use gloves and avoid exposure as much as possible when handling the blanket.  Also some of the blankets use metal Velcro – be careful or your arms will get cut!!
  11. Secure the blanket as well as you can. IMPORTANT: The V1 gate valve should be outside the blanket. Use aluminum foil to seal any gaps in the blanket. If possible cool the V1 gate valve with a small fan.
  12. Turn off the turbo pump.
  13. Turn off the Auto Valve Control
  14. Set the bakeout timer for 8 to 12 hours (8 hours is usually enough)
  15. Press the bakeout ON button and the ovens should come on. If not, check that the table top switches are not being held down by the blanket.
  16. The DIGIII setpoint 4 controls the ovens. If the pressure in the system goes above set point 4 (usually 2 to 4 X 10-6 Torr) then the ovens will shut off until the vacuum recovers.
  17. Once you verify that the system is baking then it can be left unattended until the bakeout is complete.

 

After the Bake-out.

 

  1. After the bakeout is complete, the first step is to remove the bakeout blanket.   If the system is still very hot, then open the blanket just a little bit and let it cool down for an hour or two until just warm. Then remove the blanket.
  2. Install the table tops.
  3. Turn on the AVC.
  4. Make sure that the card rack power and all units (20-610, 20-622, 11-065 and Thermo Valve) are still OFF.
  5. Re-connect all cables and preamps to the system. Use EXTREME CARE when installing the 97 SED preamp.

Once all of the cables have been connected it is safe to turn on the system normally.

It is recommended that the Lab6 filament and 11-065 ion gun control emission current be turned up very slowly the first time that they are used after bakeout in order to give them time to outgas.

How to clean a nude ion gauge

Posted on by
Reply

The ceramic feedthroughs on the nude ion gauges commonly used in vacuum chambers can become coated over time which results in non-accurate or unstable readings.  The following procedure can be used to clean the coating off of the ceramics.  Install a new filament assembly on the clean feedthrough flange and voila! – You have a rebuilt ion gauge.  RBD provides the filament assemblies for a wide variety of ion gauges.  If you can’t or don’t have the time to clean the feedthrough assembly on your coated ion gauge, RBD also provides complete ion gauges at great prices. The RBD Instruments ion gauge filaments and complete gauges can be found at this link – Low Cost Ion Gauge Filaments

 

dirty-ion-gauge-feedthrough

dirty-ion-gauge-feedthrough

cleaned-ion-gauge-feedthrough

cleaned-ion-gauge-feedthrough

 

 

 

 

 

 

 

 

 

Ion gauge cleaning procedure

Note: This procedure can be used to clean the tungsten and carbon coating off of the ion gauge ceramic feedthroughs. It is not intended for ion gauges that are contaminated with oil. If your ion gauge is contaminated with oil it should be replaced.

  1. Tape a used gasket to the flange. This is to ensure that the knife edge is protected (rule # 1).
  2. With the ion gauge flange pointing down, sandblast the ceramics with clean alumina. Avoid the grid.
  3. With the ion gauge flange pointing down, sandblast the ceramics and metal can with clean glass beads. Avoid the grid.
  4. With the ion gauge flange pointing down, move the sand blast nozzle as far away from the ion gauge as possible and sand blast the grid lightly with clean glass beads to remove any black contamination from the grid. You not want to get the nozzle too close to the grid as the air blast will damage the grid and or bend the collector wire.
  5. Shake off any excess blast material.
  6. Rinse off the ion gauge flange with water.
  7. If necessary, straighten any of the grid wires that may be bent out of position
  8. With the ion gauge flange facing down, place the ion gauge into a beaker filled with 5% Alconox or another lab detergent and water. Ultrasonic for 5-10 minutes. Warm water works best.
  9. Remove from beaker and rinse well with water.
  10. Place ion gauge flange face down in a beaker of DI water with no soap.
  11. Ultrasonic for 5-10 minutes
  12. Remove from water and rinse thoroughly with DI water.
  13. Dunk once into Isopropanol (to remove the water).
  14. Blow off excess Isopropanol (especially from inside the cap where the collector wire is located) and then dry in an air oven for 1 hour at up to 200C.
  15. Install new filament assembly.

Rebuild is complete!

When you install the ion gauge back into your vacuum chamber you will need to run it through one or two degas cycles.

Also check out the RBD Techspot blog post on how to install an ion gauge filament.

15-255G Filament Change Procedure

Posted on by
2

This post explains how to replace the C75-010 tungsten filament used in the Physical Electronics 15-255G double pass CMA.    Refer to the pictures below for more details.  RBD Instruments provides the C75-010 filaments as well as any other parts that you may need for your 15-255G analyzer.  We also offer a complete analyzer rebuild service that includes a new filament and electron multiplier.

15-255G Filament Change Procedure

 Use gloves, de-magnetize all tools and clean all tools with Isopropanol.  Set up a work area with UHV aluminum foil.  Or use regular aluminum foil and clean it with isopropanol.

Set analyzer on stand or use manuals and support analyzer on handles, facing up.

  1. Remove outer magnetic shield (3 screws)
  2. Remove inner magnetic shield (4 screws)
  3. Carefully remove conical ceramic cover.   Note that sometimes the conical ceramic will stick inside the cover. Be careful not to let it fall out if it does stick. If it falls out an breaks a replacement conical ceramic is expensive!
  4. Remove conical ceramic and carefully set it on the aluminum foil.
  5. Carefully lift inner cylinder up and off of the electron gun assembly. Note: If the inner cylinder does not move freely, use a heat gun to expand the inner cylinder so that it will slide off. Do not force it! Be careful not to damage the grids.
  6. Look at the electron gun detail to familiarize yourself with the electron gun assembly.
  7. Remove the deflection cover (3 small flat head screws)
  8. Remove the deflection support screws (4 flat head)
  9. Remove the deflection support post that is located between the two ceramic posts.
  10. Tilt the electron gun out and down so that you can access the bottom plate of the electron gun.
  11. Remove the three long screws that hold the electron gun assembly together.
  12. Remove the V1 emission screw
  13. Remove the 2 filament couplers from the filament posts. You will need a .048 4 spline wrench.
  14. Remove the 3 filament support ceramics.
  15. Remove the filament whenelt cap assembly. Note the orientation of the emission tab and filament posts as when you put the new filament in it will need to have the same orientation.
  16. Remove the 3 screws that hold the filament base on and remove the filament.
  17. Install the new filament in the same orientation as the old filament into the emission cap.
  18. Install the 3 screws and the filament base and tighten slightly.
  19. Position the filament so that it is centered in the hole and tighten the 3 screws. This is best done using a microscope. For best results the tip of the filament should be perfectly centered.
  20. Install the filament assembly on top of the 3 filament support ceramics and use the 3 long screws to hold the assembly together. The three long screws need to be tightened firmly so that they all have the same distance with respect to the base.
  21. Reconnect the V1 wire
  22. Reconnect the filament couplers.
  23. Install the deflection support post, screws and cover.
  24. Ohm out the connections to the filament and V1.
  25. Degauss the gun assembly.
  26. Install the inner cylinder over the electron gun assembly.  Line up the dead spots on the ceramic tubes.
  27. Reinstall the upper outer cylinder.
  28. Carefully install the conical ceramic. The resistor part should be 180 degrees out from the center flat ceramic. Ohm out OC (outer cylinder) to ground and make sure it has the correct resistance of 600 k ohms +/- 100 k ohms.
  29. Install the conical cover and tighten the screws firmly and evenly.
  30. Install the inner magnetic shield
  31. Degauss the analyzer.
  32. Install the outer magnetic shield.
  33. Degauss the analyzer. Installation complete.

 

This slideshow requires JavaScript.