A blog on the repair, operation and calibration of surface analysis systems and components including electron spectrometers, sputter ion guns and vacuum related hardware. Click on the Index tab below to see a list of all posts. Visit our website at http://www.rbdinstruments.com
Category Archives: General Optics and Vacuum
General information on repair, maintenance, and operation of both PHI (Physical Electronics) and other manufacturers’ systems and components
The original channeltron and channel plate electron multipliers for the older PHI (Physical Electronics) AES and XPS systems are still available through Photonis. The cost of these parts has increased substantially in the last few years, so be prepared for sticker shock the next time you need a channeltron or a set of channel plates!
Here are the Photonis part numbers for the different PHI systems:
Model Number
Where used
Photonis Part Number
4831G
15-255G, 25-120, 25-120A, 25-130, 25-270 and 25-260 cylindrical mirror analyzers. 06-600 SIMS, 590 through 660 scanning AES systems
30129
4839
10-150 and 10-155 CMA
30131
4821
5100, 5300 and 5400 XPS systems 10-360 SCA single channel detector
30117
PSD detector channel plate matched set EDR
5400 XPS system 10-360 SCA PSD position sensitive detector
30300
MCD chevron plate set EDR
5500 through 5800 XPS 10-360 SCA MCD 16 channel detector
30410
For a quotation you can call 1-508-347-4000 or request a quotation at this URL –
Recently, I have seen the same problem on several 32-095 and 32-096 X-ray source controls which are used on older Physical Electronics PHI X-ray photo electron spectroscopy systems.
The issue is that C9, a 680 uF electrolytic capacitor blows out and the electrolytic material leaks out on the board. Left unattended, the electrolytic etches and oxidizes the traces on the board.
If you have an older PHI XPS system that uses a 32-095 or 32-095 X-ray source control you should pull if out of the rack, remove the cover and inspect the board immediately.
If corrosion is present, then remove the board and remove C9. Note the polarity of C9 as the + indicator on the board may be etched away. Then, carefully clean the corrosion from the board as best as you can. If in the shop I use some Alconox and let it sit on the board for a while, then rinse with DI water and let the board dry overnight. In the field I have used isopropanol or methanol and cotton swabs. Note that if the traces are corroded badly then they may come off the board as you clean it. If so, you will need to use some fine copper wire to rebuild the traces.
Once the board is clean and dry, replace C9 with a new one. I will dig into this issue some more and try to determine why this problem occurs so often and come up with a permanent solution. In the meantime, I would recommend that the C9 capacitor be replaced every 5 years.
The pictures below show where C9 is located on the control board and what the corrosion looks like.
Update 5-28-23 – We tried this on two different pump set ups and it seemed to work well at first. But on one of the set ups the fine mesh O-ring became clogged with small Zeolite pieces and plugged up the line. We removed the Zeolite from that set up, the other one is working fine so far. It could be a function of the mesh size, we will continue to monitor set up #2.
Molecular sieve traps use zeolite pellets to adsorb water vapor, oil vapor and other gas molecules. They are particularly useful in preventing the back-streaming of oil vapor from the rotary vane pump into the turbo pump and vacuum chamber.
Molecular sieve oil mist trap
Molecular sieve traps are placed between the rotary vane backing pump and the turbo pump. Most molecular sieve traps also have built in heaters that are used to regenerate the zeolite once it becomes saturated with contaminants.
If you have an oil filled rotary vane pump, a molecular sieve trap is a must. However, molecular sieve traps can be relatively expensive running from $500.00 to $1,000.00 or more depending on the size.
This blog post shows a way to use existing flexible metal hose to make a molecular sieve trap for a lot less.
The general idea is to fill an existing flexible metal hose which is connected between the roughing pump and the turbo pump with zeolite pellets.
Step one is to remove the flexible metal hose.
Next, insert a mesh screen centering ring on the end of the flexible metal hose that is closest to the roughing pump. Connect the flexible metal hose to the roughing pump.
Once the flexible metal hose is filled completely (leave a little bit of room at the top) connect the flexible metal hose back to the turbo pump roughing port using another mesh screen centering ring.
Finally, label the flexible metal hose to indicate that the flexible metal hose is filled with Zeolite pellets.
That way when the flexible metal hose is removed at some point in the future who ever removes it will know that they need to remove the top of the flexible metal hose first and to empty the Zeolite pellets before removing the flexible metal hose from the roughing pump. You can also hold the bottom centering ring as the flexible metal hose is removed from the roughing pump. (That is one advantage that a regular sieve tap has is that the Zeolite pellets are contained and will not spill out when the sieve trap is removed from the backing pump).
In the experiment where I tried this idea the turbo pump and backing pump worked normally, there was no noticeable increase in the pumping time. At some point in the future when the Zeolite needs to be baked out heating tape could be used. Or the Zeolite pellets could just be replaced with new ones. Note that the volume of Zeolite pellets in the flexible metal hose is much less than what a regular sieve trap has, so the amount of adsorption would be reduced proportionally. Even so I think that this is worth considering, especially in situations where there is no existing molecular sieve trap installed.
Total cost for the two mesh screen centering rings and the Zeolite pellets was under $90.00 Finally, if you are not familiar with LDS you should check them out. They have a wide selection of vacuum related hardware at good prices and fun categories like REALLY Cheap Stuff and Surplus items. https://www.ldsvacuumshopper.com/drypumps1.html
