Abstract: A method and apparatus for analyzing ions by determining times of flight including using a collision cell to activate ions toward fragmentation and a deflector to direct ions away from their otherwise intended or parallel course. Deflectors are used as gates, so that particular ions may be selected for deflection, while others are allowed to continue along their parallel or otherwise straight path, from the ion source, through a flight tube, and eventually, to a detector. According to the present invention, a postselector, in the form of two deflection plates is used as an ion deflector and is encountered by ions after the collision cell as they progress through the spectrometer.

Abstract: In an ion cyclotron resonance mass spectrometer, ion cyclotron resonance signals at higher harmonics of cyclotron frequency are employed to increase the resolution of ICR mass spectrometer without increasing the magnetic field. The detection electrodes consist of M (where M is an integer) identical electrodes arranged in M-fold symmetry about the axis of the coherent cyclotron motion of the observed ions. In an ion cyclotron having four points of voltage in space, the cyclotron electrodes are set up in clockwise symmetric fashion. To increase the resolution in signal detection resulting from the potential induced by ions moving in orbits in the specrometer, the first and third voltages are added and the second and fourth voltages are subtracted from the sum of the first and third voltages.