Off-line commissioning of a non-destructive FT-ICR detection system for monitoring the ion concentration in the KATRIN beamline

Neutrino oscillations have recently proved the existence of massive neutrinos. Since then the measurement of the rest mass of the neutrino remains an open question. The Karlsruhe Tritium Neutrino KATRIN experiment aims to obtain the electron antineutrino rest mass with a sensitivity of 0.2 eV with a confident level of 95%. In the KATRIN beamline various positive ions are formed by β-decay and ionization processes (T⁺, He⁺, (³HeT)⁺, T⁺₂ ), followed by chemical reactions which also produce T⁺₃ , T⁺₅ and even larger cluster ions. The partial removal of these contaminations will be done along the transport section of the experiment. The presence and the concentrations of these contaminats have to be known when evaluating the β spectrum. To identify and measure these concentrations two identical Penning trap systems using the Fourier Transform-Ion Cyclotron Resonance (FT-ICR) method will be installed into the KATRIN beamline. The off-line commissioning of these Penning traps is the main topic of the work presented here. A test setup was built at the Max-Planck-Institute for Nuclear Physics in Heidelberg where a 3-pole cylindrical Penning trap and its electronics were tested inside a 4.7-T superconducting magnet. Measurements of the coherence time of the ion motion at different pressures, the detection limit of the tested Penning trap and its electronics, and a mass measurement for the determination of the accuracy of the tested Penning trap system are part of the characterization