Heidelberg 2015 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 43: Astroparticle Physics 2
HK 43.4: Vortrag
Mittwoch, 25. März 2015, 15:30–15:45, M/HS4
Work function studies of gold surfaces with a Kelvin Probe for the Rear Section of the KATRIN experiment — •Kerstin Schönung and Martin Babutzka for the KATRIN collaboration — Karlsruhe Institute of Technology
The KArlsruhe TRItium Neutrino-Experiment KATRIN will perform a model-independent measurement of the electron antineutrino mass. Therefore the energy spectrum of the beta electrons of a gaseous molecular tritium source will be examined. To achieve the desired sensitivity of 0.2 eV/c2 (90 % CL) the plasma potential of the tritium gas must be temporally and spatially stable within σ < 20 meV. Therefore the work function of the so called Rear Wall which defines the plasma potential must be known even more precisely and the temporal changes must be investigated.
A common instrument to measure the work function of a surface with a precision of a few meV is a Kelvin Probe. Therefore such a system was built up at the Tritium Laboratory Karlsruhe. In the talk the working principle of a Kelvin Probe and the setup will be presented. Additionally the results of the commissioning of the system as well as the results of the first work function measurements at Rear Wall like samples will be discussed.