Bonn 2020 – wissenschaftliches Programm
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T 92.3: Vortrag
Freitag, 3. April 2020, 11:30–11:45, H-HS II
Background reduction with the shifted analyzing plane configuration in KATRIN — •Alexey Lokhov — University of Muenster, 48149 Muenster, Germany — Institute for Nuclear Research RAS, 117312, Moscow, Russia
To measure the effective electron antineutrino mass mv with a sensitivity of 0.2 eV/c2 the KATRIN experiment requires the level of background of about 10 mcps. One of the sources of the background electrons are the Rydberg atoms, created in the decay of Po-210, entering the spectrometer and ionized by thermal radiation. This yields low-energy electrons, almost uniformly distributed over the vessel volume.
We present here a technique to reduce this volume-dependent background of the KATRIN main spectrometer by using a specific configuration of the electromagnetic fields (so called shifted analyzing plane with a reduced fluxtube), that effectively decreases the volume of the fluxtube of electrons while preserving the energy resolution and allowing for the required neutrino mass sensitivity. The dedicated tests, which were performed recently, investigated the background reduction in this configuration and studied the EM fields at the shifted analyzing plane by calibration measurements using the Kr-83m conversion electrons and electron gun as reference sources.