MASS SPECTROSCOPE

摘要

One virtual rod electrode is composed of electrode blanks arranged in the direction of an ion optical axis. A virtual quadrupole rod-type ion transport optical system (30) is constituted by placing four virtual rod electrodes around the ion optical axis. In one virtual rod electrode, the distance between adjacent electrode blanks is set wide in the first half region (30A) and set narrow in the second half region (30B). The wider the distance between electrodes, the more the number of high-order multipole filed components becomes, therefore ion acceptance increases, and ions coming from a previous stage can be efficiently accepted. On the other hand, the narrower the distance between electrodes, the relatively more the number of quadrupole field components becomes, therefore ion beam focusing improves, and ions can be efficiently introduced into, for example, a quadrupole mass filter at a subsequent stage. This contributes to the improved sensitivity and precision of mass spectroscopy.