We have a UHV ion gun that has become sporadically erratic. The main problem is, it quits after a short time of operation. The window of operating time is getting shorter. I suspect this is due to a conductive film building up on the insulators. We may have to break vacuum and spend either much time or much money to rebuild the gun.
Before we do this, I seem to recall that UHV systems can be baked in a low pressure of O2 background to try to burn off contaminates from insulators on electron and ion guns.
Does anyone have a procedure to reference or share to address this? I would also be just as glad to hear the method is the equivalent of a myth so that I can put my thoughts aside.
Dear jeffrey, we have had a duo-plasmatron source from PHI in operation in the past. After each contact to laboratory air, i.e. after each time we have opened the vacuum chamber, this source needs to be operated with Oxygen instead of the noble gases usually employed. We have had a service technician who showed me this trick - and it seems to work. Maybe the same procedure may also work with your gun? I would suggest to check the manual whether or not your gun may be operated with oxygen as sputter gas. If the latter applies, it could be a chance ... Good luck, and keep us updated about your progress
Dirk
Dear Jeffrey,
If you are using the ion gun as a "ion milling system", may other materials are being deposit onto the gun window. In this case, you really need break the vacuum to open the system to clean up the components. This usually doesn't happen very offen (or should not happen), if your system have to be turned off frequently, you may have other issues. In the case to evacuate the chamber again, I would say that you have to bake it in high vacuum to eliminate the adsorbed gas on the inner wall. Also, check the vacuum pumps (mechanical, turbo and cryo ones), sometimes we have back flux of hydrocarbons from them into the system, which may compromise the operation of the ion gun.
When you find the problem and its solution, share with us, please!
Best.
Thanks for the comments so far.
As a follow up, the ion gun is used for charge neutralization in XPS and for sputter profiling. It is a PHI 5000 v1 instrument. The ion gun sat for a long period unused and has had rather frequent exposure to air.
Thank you to everyone who responded. The problem was related to a leak on the feed line to the ion gun. It has been resolved.
We have since discovered the problem. A flange to the Ar cylinder had a leak. We were likely saturating the ion gun with inappropriate amounts of air. Now that we have fixed the leak, the sporadic behavior has since disappeared. Thank you to all for inputs, and consider this question closed.
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