Russian-German beamline at BESSY II - Experimental station

Experimental Station

You can find the description of the RGL-station here.

In November 2010 the experimental station at the Russian-German beam line of the BESSY-II facility has been deeply upgraded and is now ready for your experiments. The new instrumentation is very flexible and we expect reliable performance for the whole variety of experiments of our user community. Having several preparation chambers, fast-load systems, a number of insertion devises such as a flash-machine, a cleavage system, a heating stage, a gas-inlet system etc., the station is a powerful instrument allowing to study fundamental properties of matter. Furthermore, an analytical chamber has been configured in a way that it now allows to study a particular physical process or a chemical reaction in real-time.

Technical design concept of the experimental station at the Russian-German beamline at BESSY-II facility
Experimental station. General view

The experimental station (RGL-station) is equipped with PHOIBOS 150 electron-energy analyzer with the 2D CCD detector system (SPECS GmbH), which simultaneously offers both energy and angular resolution and allows band mapping as well as high resolution XPS/UPS. The MCP-LEED system (Omicron GmbH) allows to explore LEED from rather delicate systems like organic molecules and electrically insulating surfaces. The specific advantage of the multi-channel plate (MCP) detector is that it allows electron beam currents down to 0.1 nA. The endstation includes a new cryo manipulator (lowest temperature about 20K) which allows polar and azimuthal rotations of the sample and motions along the x, y, and z axes. It is operated by a set of stepping motors allowing easy handling of the sample with a joystick and quite user-friendly computer interface. The following brief description shall help our user community to elaborate, prepare and perform sophisticated research programs at the renewed RGL equipment.

The experimental station consists of three chambers. The upper one is positioned right above the analytical chamber and dedicated for "clean" experiments with rather delicate and reactive materials like rare-earth elements. It is equipped with a quartz microbalance, flanges to mount evaporators (CF35 and CF63), a gas inlet system, a flash-machine, a wobble stick, an ion gun, a few windows, a manipulator and a fast-entry system. Here, thin films can be deposited in-situ from Knudsen cell-type evaporators. Surfaces of bulk samples can be prepared by several methods: (a) cleaving; (b) sputtering; (c) heating up to 2000°C; (d) scraping.

Measurements are done in the analytical chamber, which is equipped with (i) a PHOIBOS 150 electron-energy analyzer, (ii) an MCP-LEED system, (iii) a partial yield electron detector and (iv) an X-ray tube. A port for the installation of a fluorescence detector is foreseen. Optionally, a few flanges CF63/CF35 can be used to mount evaporator sources. This allows time-dependent experiments where metal deposition and PE data acquisition are done simultaneously. It is important to note that only rather non-reactive materials like Ag, Au etc. can be used for this purpose.

The Russian-German dipole beam line was proven to be highly suited for spectroscopic investigations of "fragile" organic and biological molecules which generally show enhanced sensitivity to x-ray damage effects. In order to handle these systems the "side" preparation chamber was elaborated. Basically, it has a similar set of insertion devices as the "top" one, however, it is believed that such delicate materials like organic molecules, polymers, proteins, DNA etc will only be treated in this instrument.

The analyzer.

Operation modes:
- angular integrated
- with angular resolution

- range of operation
0 to 3500 eV
- energy resolution
better than 7 meV
- angular resolution
better than 1°
Energy Analyzer Series PHOIBOS 100/150

The descriptions and manuals for analyzer (d, m), programm for measurements (m) and for LEED in "side" preparation chamber (d, m) are available.