Dresden 2017 – wissenschaftliches Programm

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VA: Fachverband Vakuumphysik und Vakuumtechnik

VA 2: Large Vacuum Systems

VA 2.2: Vortrag

Montag, 20. März 2017, 11:45–12:15, HSZ 301

Performance of the KATRIN Cryogenic Pumping Section — •Carsten Röttele and KATRIN Collaboration — Karlsruhe Institute of Technology (KIT), IEKP, Postfach 3640, 76021 Karlsruhe

The Karlsruhe Tritium Neutrino (KATRIN) experiment uses the kinematics of electrons from the tritium β-decay to determine the effective neutrino mass with a sensitivity of m_ν= 200 meV/c² (90% C.L.). Produced in the windowless gaseous tritium source (WGTS), the β-electrons are magnetically guided through the beam lines of the transport and pumping section to the spectrometer, where their energy is analysed. The transport and pumping section comprises two parts, the differential pumping section (DPS) and the cryogenic pumping section (CPS). Tritium decaying inside the spectrometer would increase the background rate. Therefore the pumping sections have to reduce the tritium flow from the WGTS by at least 14 orders of magnitude. This talk introduces the CPS, which has been designed to reduce the tritium flow by more than seven orders of magnitude. The tritium is cryosorbed on a 3-K-cold layer of argon frost that covers the gold-coated stainless steel surface of the beam tubes with an area of about 2.5 m². The temperature distribution along the cold trap, which is important for the effective reduction factor, has been simulated with COMSOL multiphysics. Results of the simulation will be presented and compared with first experimental data. This work was supported by GRK1694, BMBF (05A14VK2), KSETA and the Helmholtz Association.