Omicron UHV system at OEPV/KAUST


​During my PhD at KAUST, I had the chance to experience the installation of the first ultrahigh vacuum multiprobe and MBE systems on campus in 2011, which have formed a major part of my life as a PhD student. I have been part of the commissioning and installation of the system, hands-on training from the visiting engineers from Omicron, maintenance of the system (calibrations, changing filaments, diagnosing leakage and bake-outs), designing and installing upgrades and running experiments with special focus on photo-electron spectroscopy (XPS and UPS).
Working with a UHV systems might appear complicated task at the first, considering the shiny stainless steel chamber, dozens of tubing and electrical wiring, various view ports, gas cylinders and manifolds and radiation warnings all over the system, as if it was a submarine or a spaceship! However, once you master a UHV system and the various attached component, it becomes the most joyful instrument you will ever deal with.
My expertise with the Omicron UHV system have developed through shadowing the installation engineers and providing assistance from moving the huge crates around, installing the various components, loading materials, diagnosing errors, changing filaments to pumping down the system and baking-out. After the commissioning and the installation phase, I was one of three PhD student who were involved in the extensive training provided by Dr. Deler Langernberg; which involved samples loading, heating or cooling the sample stage, calibration of various components, XPS and UPS experiments and data analysis, usage of mass spectrometers, sputtering, charge neutralizing and molecular beam epitaxy. This was an enriching training, but only formed the foundation of my system experience. 
Due the multi-component nature of the system, it required a proper management and maintenance cycle. A team formed with the name UHV team was formed in our lab, it involved me and two other PhD students. The role of the team was to create standard operating procedures, provide training for future users, discuss urgent issues and either solve them or liaison with the suppliers, in addition to assuring the system pressure is maintained by designing a form based logbook for each component and experiment done in the system. The team spirit and collaborative work in the UHV team have sustained the UHV system in our lab running without issues or delays for the past 5 years. 
In addition, I was exposed to designing new UHV components for specific experiments with the assistance of Dr. Habib Katsiev. The design aimed to having a filament close to the proximity of the sample stage to crack molecular gases to the atomic species. After a long discussion of the design, I was in charge of ordering the components (z-arm translators, feedthroughs, fliaments), and then the assembly of the components and installation to the system was done under the supervision of Dr. Katsiev. 

System Description
•Organic MBE/MBD with in-situ RHEED and ellipsometry
• X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS) with sputtering and charge neutralizing capabilities
• Variable temperature STM/STS and Q-Plus nc-AFM
• Sample transfer to/from nitrogen glove box (solution-processing, device fabrication and testing)

My perspective of UHV systems
The best way to deal and understand with such systems is for the user to divide they system in various component, study the working principle of each component separately, 
  • Pumping system (Pressure gauges and pumps)
  • various smaller machines (Evaporation sources, radiation sources, analyzers, spectrometers) 
  • All these machines are tightly connected in a set of chambers. 
  • The chambers are tightly attached to each other by various tubing an connections, with optional separation via gate valves.
  • Translation components to move samples around the system.
Always visually (physically if possible) follow the tubes from the pumps to the valve to the chamber or to any point in the system to identify what would be the safest procedure to run the experiment without affecting the vacuum in the system. ​
Before opening any gate valve, check the chambers/connections that are connected to the gate you need to open, and make sure that the pressure on each side of this gate is equal.