The KATRIN experiment is designed to measure the mass of the electron neutrino directly with a sensitivity of 0.2 eV. It is a next generation tritium beta-decay experiment scaling up the size and precision of previous experiments by an order of magnitude as well as the intensity of the tritium beta source. The project is located at the Forschungszentrum Karlsruhe (FZK) in Germany and involves collaborators from all over the world.
The ASTeC vacuum science group has been involved in 3 key areas of the machine, the Tritium transport section, the main spectrometer and the focal plane detector (FPD). This paper focuses on the design of the FPD highlighting the requirement for XHV and the use of Monte-Carlo modelling to determine a suitable design. The paper will also discuss the technological challenges that have been overcome, such as the operation of sensitive vacuum equipment in large stray magnetic fields (10000 Gauss) and how the low temperature 'in-situ' bakeout requirement has been overcome in order to achieve satisfactory outgassing rates for XHV.
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