München 2009 – scientific programme

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T: Fachverband Teilchenphysik

T 101: Niederenergie-Neutrinophysik & Suche nach dunkler Materie 2

T 101.7: Talk

Tuesday, March 10, 2009, 18:20–18:35, A140

The Penning trap between the pre- and main spectrometers of the KATRIN experiment — •Ferenc Glück — Universität Karlsruhe (TH), Institut für experimentelle Kernphysik

The purpose of the KATRIN experiment is to measure in a model independent way the neutrino mass down to 0.2 eV, using electrostatic retardation with magnetic adiabatic collimation. In standard operation mode, there is an 18 kV deep Penning trap between the pre- and the main spectrometers of the experiment. In this trap, a Penning-type discharge could ignite, and this could cause a large background. Using a detailed Monte Carlo simulation, with electron trajectory calculations, electron collisions with residual gas molecules and synchrotron radiation, we computed the ionization rate of the electrons inside the trap. Due to electron trapping, a strong electron multiplication process takes place. One incoming primary electron, together with the many trapped secondary electrons, creates about 100 million positive ions in the Penning trap. These ions produce background secondary electrons inside the main spectrometer. The electron trapping, multiplication and thus the production of the large background could be prevented by inserting a thin wire into the trap; this wire could be either fixed or movable.

Supported by BMBF grant under label 05A08VK2