Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)
O 35.97: Poster
Dienstag, 27. März 2012, 18:15–21:45, Poster B
Investigations of the Patch Effect with a Scanning Kelvin Probe — •Gertrud Konrad1,2, Stefan Baessler3, Iain Baikie4, Henry Bonner3, Werner Heil2, Rachel Hodges3, Thorsten Lauer2, Sean McGovern3, and Xuying Tong3 — 1Atominstitut, TU Wien, Austria — 2Universität Mainz, Germany — 3University of Virginia, Charlottesville, USA — 4KP Technology Ltd., Wick, UK
Precision measurements of observables in neutron beta decay address important open questions of particle physics and cosmology, and are generally complementary to direct searches for new physics beyond the Standard Model in high-energy physics.
The analysis of the decay protons is based on a precise energy measurement, by means of an electrostatic filter or by TOF measurement. Then the electric potential between the decay and filter regions has to be known with an accuracy of better than 10 mV. Possible inhomogeneities of the work function (WF) at the electrode surface vary the electric field distribution. On the inside of a cylindrical electrode, a spatial variation of order of 100 meV over a distance of several cm was found. A scanning Kelvin probe (SKP) has been used to map the WF, with a spatial resolution of 2 mm and a WF resolution of 1 − 3 meV. To minimize the WF variations, different surface materials, treatments, and coatings are being investigated. A platinized surface yielded a RMS WF value of better than 10 meV. Coating adhesion and surface roughness have a significant influence on the measured WF values.
The physics motivation, the SKP technique as well as the status of the investigation will be presented in this talk.