In this work, we present the first spectroscopic measurements of conversion electrons originating from the decay of metastable gaseous 83mKr with the Karlsruhe Tritium Neutrino (KATRIN) experiment. ...The obtained results represent one of the major commissioning milestones for the subsequent direct neutrino mass measurement with KATRIN. The successful campaign demonstrates the functionalities of the KATRIN beamline. Precise measurement of the narrow K-32, L3-32, and N2,3-32 conversion electron lines allowed to verify the eV-scale energy resolution of the KATRIN main spectrometer necessary for competitive measurement of the absolute neutrino mass scale.
The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to determine the effective anti-electron neutrino mass with a sensitivity of 0.2eV/c2 by using the kinematics of tritium β-decay. It is crucial ...to have a high signal rate which is achieved by a windowless gaseous tritium source producing 1011β-electrons per second. These are guided adiabatically to the spectrometer section where their energy is analyzed. In order to maintain a low background rate below 0.01cps, one essential criteria is to permanently reduce the flow of neutral tritium molecules between the source and the spectrometer section by at least 14 orders of magnitude. A differential pumping section downstream from the source reduces the tritium flow by seven orders of magnitude, while at least another factor of 107 is achieved by the cryogenic pumping section where tritium molecules are adsorbed on an approximately 3K cold argon frost layer. In this paper, the results of the cryogenic pumping section commissioning measurements using deuterium are discussed. The cryogenic pumping section surpasses the requirement for the flow reduction of 107 by more than one order of magnitude. These results verify the predictions of previously published simulations.
•Measurement of the reduction factor of KATRIN’s cryogenic pumping section with deuterium.•Safe tritium retention can be concluded.•More than 108 gas flow reduction.
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