Wuppertal 2015 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
T: Fachverband Teilchenphysik
T 71: Niederenergie Neutrinophysik V
T 71.5: Vortrag
Mittwoch, 11. März 2015, 17:50–18:05, I.13.70 (HS 27)
Investigation of UV-laser induced electrons in the KATRIN main spectrometer — •Johannes Weis and Daniel Hilk for the KATRIN collaboration — Institut für experimentelle Kernphysik, KIT, Karlsruhe
The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to determine the effective mass of the electron anti neutrino with a sensitivity of 200 meV/c2 via the precise measurement of the tritium beta decay spectrum close to its endpoint energy of 18.6 keV. To achieve the desired sensitivity a very low background rate of 10−2 electrons per second is necessary. Cosmic muons produce a large number of secondary electrons at the inner surface of the KATRIN main spectrometer. These secondary electrons are mostly suppressed via magnetic shielding effects, however some of these electrons can reach the focal plane detector and contribute to the background. In order to shield these electrons, an electrostatic retarding potential is produced by a dual-layer wire electrode system, installed at the inner surface of the spectrometer vessel.
An UV laser system is used to generate a large number of low-energy secondary electrons via photoelectric effect at dedicated positions inside the main spectrometer vessel. These electrons are used to investigate the efficiency of the electrostatic shielding for different electrode potentials. This talk presents measurement results recently obtained in context of the second commissioning phase of the main spectrometer. This work was supported by the BMBF under grant no. 05A11VK3 and by the Helmholtz Association.