Filar ion cyclotron resonance ion trap: Spatially multiplexed dipolar and quadrupolar excitation for simultaneous ion axialization and detection

A novel Fourier transform ion cyclotron resonance ion trap consists of two conventional solid ‘‘end cap’’ electrodes and four ‘‘filar’’ electrodes, each composed of two interdigitated ‘‘combs.’’ The filar trap provides for ion dipolar excitation and ejection, dipolar detection, quadrupolar axialization, and various combinations in a single trap without additional voltage divider circuitry and signal switching between operating modes, because two different functions can be conducted simultaneously by use of two spatially multiplexed electrodes. The filar electrodes produce simulated dipolar and quadrupolar potential fields which are nearly indistinguishable (near the trap center) from those produced by solid electrodes.