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.