Time-of-flight mass spectrometer using an imaging detector and a rotating electric field

Katayama, Atsushi ; Kameo, Yutaka ; Nakashima, Mikio

A new technique is described for minor isotope analysis by using a rotating electric field and an imaging detector. The rotating electric field is generated by cylindrically arranged six plane electrodes with multi-phase sinusoidal wave voltage. When ion packets that are discriminated by time-of-flight enter the rotating electric field, these are circularly deflected and make a spiral image on fluorescent screen of detector. This spiral image represents m/z values data as position of ions and abundance of ions as brightness. For minor isotopes analysis, the micro channel plate detector is used under gate control operation to remove from influence of high intensity of major isotopes.