| 摘要 |
In an ion reflector (4) configured from a plurality of electrodes, electrodes 42 disposed in a second stage region (S2) for reflecting ions after deceleration are formed thinner than electrodes (41) disposed in a first stage region (S1) for decelerating the ions. The thin electrodes suppress unevenness of potential, in particular, in a path away from the center axis of the reflector, which results in improvement of isochronism of an ion packet passing on the path. The thick electrodes (41, 43) disposed in the first stage region (S1) prevents stretching of the grid electrodes (G1, G2) from being affected, and unevenness of potential in the first stage region (S1) hardly affects isochronism of the ions. By appropriately adjusting thicknesses and a pitch of the electrodes (41, 42, 43, 44) adjacent to one another so as to align intervals between the electrodes (41, 42, 43, 44), it is possible to use spacers having the same size in common. Since the number of electrodes in the first stage region (S1) can be reduced, an increase in costs is suppressed. Consequently, it is possible to bring an electric field of an ion reflection region closer to an ideal state and improve mass-resolving power while suppressing costs. |
