SHARING A PAIR OF ELECTRODES BETWEEN EXCITATION AND DETECTION IN A FOURIER-TRANSFORM ION-CYCLOTRON RESONANCE MASS-SPECTROMETER

Time-sharing of electrodes between excitation and detection for Fourie r transform (FT) study of the coherent cyclotron motion of ions is dis cussed, together with the choice of a suitable commutation device. A p ractical implementation is described, and the application to an open-e nd, flat, ion cyclotron resonance cell presented. In addition, the swi tching technique described is useful to minimise ion losses due to res istive damping at the magnetron frequencies, and could also be used in conventional FT ion cyclotron resonance cells for quadrupolar excitat ion and detection, and for ion axialization.