Münster 2017 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 56: Neutrinophysik 4 (Doppelbetazerfall und Massen)

T 56.8: Vortrag

Dienstag, 28. März 2017, 18:35–18:50, VSH 118

Ion detection, blocking and removal in the KATRIN experiment — •Manuel Klein for the KATRIN collaboration — Karlsruhe Institute of Technology

The KArlsruhe TRItium Neutrino (KATRIN) experiment aims at the model independent measurement of the electron neutrino mass. It is designed for a neutrino mass sensitivity of 0.2 eV (90% CL) after three years of measurement time. KATRIN measures the end point of the tritium beta-decay spectrum using a MAC-E filter and a Windowless Gaseous Tritium Source (WGTS). While neutral tritium gas molecules are pumped through the WGTS, the decay electrons are guided to the detector by a magnetic field. Tritium ions, however, would also follow the magnetic field lines to the Pre- and Main Spectrometer (PS and MS), where they could cause background by ionisation and contamination. Preventing this is imperative for KATRIN measurements.

Concepts of ion detection, blocking and removal were tested successfully during KATRIN First Light measurements in November 2016. Deuterium ions were detected with either the MS or PS at high voltage via secondary electrons, produced when the ions ionised residual gas. The ions were blocked in the beamtube by applying a positive potential with ring electrodes. Also, the ions were removed with dipole electrodes via E× B-drift or with the PS at negative potential, moving the ions non-adiabatically into the PS walls. These results show that the methods of ion detection, blocking and removal work as intended.

Supported by BMBF (Ø5A14VK2) and by the Helmholtz Association.