Dipolar and quadrupolar detection using an FT-ICR MS setup at the MPIK Heidelberg

Abstract

Dipolar and single-phase two-electrode quadrupolar detection schemes have been investigated at a Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) setup built for the KATRIN experiment at the Max-Planck-Institute for Nuclear Physics (MPIK) in Heidelberg. We present first experimental results of Li-7(+) signals from a cylindrical Penning trap configuration for both detection schemes. While the prominent signal of the conventional dipolar detection scheme marks the reduced cyclotron frequency, the main signal for the quadrupolar detection appears at the sum of the reduced cyclotron frequency and the magnetron frequency. For ideal trapping fields, this sum frequency equals the ion cyclotron frequency nu(c) = qB/(2 pi m). Sidebands due to the combined motions of the cyclotron mode and magnetron mode are observed by quadrupolar detection which allows the determination of the respective combinations of eigenfrequencies.