TIME-OF-FLIGHT MASS SPECTROMETER

摘要

Provided is a time-of-flight mass spectrometer having an ideal reflectron which eliminates energy dependency of the flight time of ions having the same m/z while ensuring a high degree of design freedom. An electric field created by the reflectron is virtually divided into a decelerating region (B) for decelerating ions and a reflecting region (C) for reflecting ions. The decelerating region (B) is defined by one or more kinds of potential distributions arrange along a central axis, such as a one-stage uniform decelerating electric field or two-stage uniform decelerating electric fields. As for the reflecting region (C), its potential distribution is determined so that, for an ion having a certain mass-to-charge ratio which has departed from a predetermined point with initial energy higher than U d , the total flight time required for the ion to travel through a free-flight region (A) and the decelerating region (B) into the reflecting region (C), turn around in this reflecting region (C) and return to the original point will be equal to the total flight time required for an ion of the same mass-to-charge ratio to make a round trip in which the ion turns around at a point of the reference potential value at the boundary between the decelerating region (B) and the reflecting region (C) or in the decelerating region (B).