Alexander Schiesser, student at the Institute for Physical Chemistry at the TU Darmstadt, created a gadget with which the adsorption heat of small organic molecules (e.g. isopropanol) can be measured by monocrystals (e.g. platinum (111)).
The ultra high vacuum gadget consists of several components.
1. With the aid of the microcalorimeter, the heat quantities are detected, which arise when a molecule hits a previously cleaned surface in the ultra-high vacuum. The functionality can be compared to that of a motion detector, which also responds to thermal radiation.
2. A gas meter generates gas pulses which contain only 10E13 molecules.
3. The gas is in turn measured by means of a quadrupole mass spectrometer.
Overall view of the ultra high vacuum gadget
In order to obtain the maximum possible accurate measuring values, it is important that the components of the gadget (mainly stainless steel) emit only a low amount of gas at this low pressure, but remain flexible. The igus® plain bearings were able to render an excellent service here. They provide for the necessary flexibility and simultaneous precision despite the particularly very high temperatures (up to 180°C during baking out of the gadget).
The system finds application in the determination of surface reactions and could assist in the manufacture of made-to-order catalyzers.