Dresden 2017 – wissenschaftliches Programm

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VA: Fachverband Vakuumphysik und Vakuumtechnik

VA 4: Poster Session

VA 4.2: Poster

Montag, 20. März 2017, 14:45–16:00, P2-OG3

Simulation of thermal and radioactive impacts on the CPS performance — •Lutz Schimpf and KATRIN Collaboration — Karlsruhe Institute of Technology (KIT), IEKP, Postfach 3640, 76021 Karlsruhe

The transport section of the Karslruhe Tritium Neutrino experiment (KATRIN) has two main tasks, which are the adiabatic guidance of the β-electrons from the Windowless Gaseous Tritium Source to the spectrometer section and to lower the tritium flow into the spectrometer section by at least 14 orders of magnitude. This huge reduction of the tritium flow is achieved by a reduction of seven orders of magnitude in the Differential Pumping Section and another seven orders in the Cryogenic Pumping Section (CPS). Two thirds of the beam tube inside the CPS is being operated at a temperature of 3K to adsorb the tritium molecules on a argon frost layer. The pumping performance during an operation interval of 60 days does strongly dependent on the homogeneity and the temporal stability of the beam tube temperature, as well as on the radioactive impact of tritium β decays inside the argon frost. To investigate these time and geometry dependent problems a custom-made simulation program has been developed. This program, based on time dependent desorption probabilities, is used to simulate the time distribution of the gas migration along the beam tubes, and to calculate its suppression factor. Simulation results will be presented both for deuterium used during commissioning and for tritium used in standard operation. This work has been supported by BMBF (05A14VK2), KSETA and the Helmholtz Association.