| 摘要 |
In this invention, an ion reflector (32) has a configuration in which multiple flat electrodes (321) are aligned, each flat electrode having a rectangular opening (322). The arrangement of each portion is defined in such a manner that the central axis line (322A) of the opening (322) in the long edge direction is positioned in a plane containing a central axis line (X axis) in the ion emission direction, and a straight line (Y axis) linking a central position (4A) on the detection surface of the detector (4) to an ion distribution mass center position (2A) in an ion trap (2). In this manner, when the electric potential distribution along the central axis of an ion reflector (32) is such that a portion of the reflection electric field is turned into a non-uniform electric field so as to improve isosynchronism among an ion group to be detected, a region that is an ideal electric potential distribution for realizing isosynchronism spreads in the Y-axis direction, facilitating settling of an ion flight trajectory into a region that is an ideal electric potential distribution. In addition, while emitted ions spread widely in the Y-axis direction during flight, passage of the spread ion through the region that is an ideal electric potential distribution is also facilitated. This allows high isosynchronism and high mass resolution to be achieved. |
