| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce a turnaround time in which ions are emitted from an ion trap, thereby improving a mass resolution. <P>SOLUTION: In the final stage of a cooling process before ion emission, a frequency of square wave voltage applied to a ring electrode in order to form a capture electric field is raised for a period of several cycles. As a result, a confinement potential inside an ion trap becomes shallow and the speed of captured ions drops. Accordingly, a turnaround time of ions in which the application of square wave voltage is halted and an acceleration electric field is thereby formed is shortened, and a variation in flight times of ions with the same mass-to-charge ratio is reduced. For reasons that the confinement potential becomes shallow, icons expand spatially, but, if a time in which a frequency is raised is predetermined so that the expansion will settle within an energy width correctable by a TOFMS, it is possible to improve a mass resolution. <P>COPYRIGHT: (C)2012,JPO&INPIT |
