Isotopes for fundamental research in 83Kr for KATRIN

6 Contents Introduction The advantage of radioisotopic standards compared to other physical standards is the independence of their properties from outer conditions. They are neither sensitive to temperature change nor to progress of time. They serve as influence-free-etalon. That is why their use is advantageous in fundamental research, where high precision is required. For instance in direct neutrino mass measurement experiments utilizing tritium β-decay. In this process a helium ion, an electron and an electron antineutrino are emitted: T → 3 He + + e − + ¯ ν e. Since a 3 He ion is massive, almost all energy is carried away by the electron and the antineutrino. Careful analysis of the electron kinetic energy at the right end of the β-spectrum (endpoint region) can bring the information about the neutrino mass. The Karlsruhe Tritium Neutrino mass experiment (KATRIN) is a next generation tritium β-decay experiment, which aims to determine the electron an-tineutrino mass with one order of magnitude better than the Mainz and Troitsk experiments, namely at 0.3-0.35 eV/c 2. If no mass signal is observed, an upper limit for the neutrino mass of 0.2 eV/c 2 (90% C.L.) will be set. The KATRIN spectrometer is a realisation of a MACE Filter (Magnetic Adiabatic Collimator combined with Electrostatic Filter) concept, to filter electrons at the endpoint interval of 18.6 keV of the tritium β-spectrum. A potential of 18.6 kV will be applied to the central electrode of the main spectrometer. The smearing out of this potential leads to imprecise knowledge about the neutrino mass. Consequently it was decided to control the potential with a high voltage divider and a nuclear standard at 3 ppm precision. The 83m Kr possessing 17.8 keV conversion electron 8 Contents line, which is only 0.8 keV less than the tritium β-decay endpoint is an ideal candidate for the role of a standard. The retarding voltage will be applied to the main spectrometer and a smaller spectrometer called a monitor spectrometer. On the monitor spectrometer the conversion electron line from 83m Kr will be observed continuously. A potential of 800 V will be applied to a 83m Kr source to give additional kinetic energy to the conversion electrons. In this work the production of 83m Kr from its parent isotope 83 Rb and the emanation of 83m Kr for the purposes of the KATRIN experiment is studied. The second part of the current thesis …