Parametric-mode-excitation/dipole-mode-detection Fourier-transform–ion-cyclotron-resonance spectrometry

A new excitation/detection scheme for Fourier-transform–ion-cyclotron-resonance (FT-ICR) studies is described. The ions are created in the center of a hyperbolic Penning trap and excited to a large magnetron radius. Parametric-mode excitation is used to drive the cyclotron motion. The ions are detected in the conventional dipole-mode detection scheme by use of a segmented ring electrode. Since the resonance frequencies of excitation (ν+−ν−) and detection (ν+, the reduced cyclotron frequency) differ by the magnetron frequency (ν−), this method allows the simultaneous excitation and detection of the ion motion.