Interview with Dr. Alexei Nefedov

Interview with Dr. Nefedov about UHV Multichamber XPS - IR system installed at Karlsruhe Institute of Technology.

Interview with Dr. Alexei Nefedov

from Karlsruhe Institute of Technology in Germany

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1. Dr. Alexei Nefedov, You ordered a multitechnique UHV system with integrated IR technique. Why did You choose this configuration? What is the goal of your research?

Yes, we ordered a multi-technique UHV system, where the IR spectrometer being a central part of this system. All other techniques such as XPS/UPS/Auger spectroscopy, thermodesorption spectroscopy (TDS), LEED, etc. are standard techniques and they are available for studies in many research laboratories. Infra-red adsorption spectroscopy (IRAS) is also the standard technique, but it is usually applied at ambient conditions. A few yeas ago your company developed a special ultra-high vacuum chamber for IR-spectrometer that allows to carry out IRAS experiments under UHV conditions at low (T=100K) temperatures. Now with this system we are making the next step. Firstly, a new LHe cryostat was developed for the IR chamber, secondly the FTIR spectrometer Bruker VERTEX 80v was combined with other surface analytical techniques (electron spectroscopies, LEED, TDS). This exclusive combination enables us to carry out high quality IR spectroscopy measurements both in reflection-absorption at grazing incidence on well-defined, perfectly flat substrates and in transmission for polycrystalline powder. All these analytical techniques, together with an opportunity to prepare samples and modify them under UHV conditions, allow us to carry out experiments, which could not be done elsewhere. The main goal of our research is the study of molecular interactions on surfaces of solid matter which are in contact with natural and technical systems. In particular, an essential aim of the research consists in a better understanding of the chemical-physical processes of the interaction of small molecules such as CO, CO2, O2, H2O, organic hydrocarbons, etc. on the metal oxide surfaces. Another direction is in material science, and studies on the surface chemistry of nanometer-scale new oxide materials for the development of highly efficient solid fuel cells are in our focus as well.


2. How do you rate our transferring system? Used for transferring between two distribution chambers, does it meet your expectations?

I have used your transfer system during the last 2 years and it absolutely satisfies my requirements. Yes, the transfer system is quite delicate and it is necessary to be very careful and attentive during its operation, however after a quite short training any scientist can safely transfer samples from one chamber to another within less than 1 minute.


3. During tests on the helium manipulator in the IR chamber we went down to a temperature of 28 K with our standard PTS sample holder, which was much lower than the original specification, are You happy about the solution and results?

We achieved temperatures of 28 K with the use of another cryostat developed by PREVAC, but the cryostat developed for the IR chamber has a quite complicate geometry, therefore to reach such temperatures, it was initially much more difficult. But here I would like to mention another parameter, namely the cooling rate. Before we needed at least 45 minutes to reach the lowest temperatures, but with this cryostat it takes not more than 15 minutes. It is really fantastic! All results exceed my expectations.


4. You work on several of PREVAC's systems at different research centers, can You tell us something about You experience with PREVAC's equipment?

I am familiar with PREVAC systems installed at the University of Bochum and the University of Heidelberg but most of my experience is with the NEXAFS/XPS system installed at the synchrotron facility BESSY in Berlin. The synchrotron NEXAFS/XPS system must operate continuously for a few weeks or even months without interruption for e.g. service work or repair. Secondly, the system must be really "user-friendly", because at the synchrotron facility some users come to perform experiments without any understanding about this machine and they must become familiar with its operation after only a short training period. Fortunately, the PREVAC system installed at BESSY fits these requirements perfectly, not only for me, but my colleagues using this system as well, we are extremely satisfied with it.


5. Could You tell us something about your co-workers? What are their responsibilities? What are their impressions about the system?

Yes, of course, with great pleasure. Since it is absolutely clear that such a system could be operated by a team effort only, such a team was already organized during designing of the system and all members of the team, namely Ms. Maria Buchholz, Dr. Carsten Natzeck , Dr. Hikmet Sezen and Mr. Stefan Heissler, brought their own experience to the design process. They all are experienced scientists; Dr. Natzeck and Dr. Sezen are specialists in photoemission spectroscopy, Ms. Buchholz and Mr. Heissler are experts in IR spectroscopy. Together they have experience in the operation of several PREVAC machines, since they have already carried out experiments in Bochum (IR spectrometer) and at BESSY in Berlin (NEXAFS/XPS system). Ms. Buchholz, Dr. Sezen and Dr. Natzeck came with me to visit PREVAC, Mr. Heissler will join during the tests in Karlsruhe.



Dr. Carsten Natzeck: For me as a future manager responsible for this powerful system, the professional implementation of specific customer demands is very impressive. The excellent functional high-precision manipulator transfer system is particularly noteworthy.






Dr. Hikmet Sezen: Our new PREVAC system provides us many innovative prospects to conduct never attempted scientific experiments up to now and to study surface phenomena with many vacuum techniques under continuous UHV conditions. It is important to note that the system has a very adaptable design for possible expansion and modification in the future.





 Ms. Maria Buchholz: The whole system is really impressive. I like the user-friendly and easy transfer system, this is a big advantage when working alone with the system. I am looking forward to our first results.







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