ION TRAP MASS SPECTROGRAPH

摘要

While applying a rectangular wave voltage to a ring electrode (21) such that ions already captured by an ion trap (20) are not diffused, frequency of the rectangular wave voltage is increased temporarily at such a timing as the ions generated in response to short time laser light irradiation reach an ion inlet (25). Consequently, Mathieu parameter q_z lowers and since the potential well becomes shallow, the ions can enter the ion trap (20) easily. On the other hand, the ions captured already are diffused easily but since the frequency of the rectangular wave voltage decreases before the ions deviate from a stable track, scattering of ions can be avoided. The quantity of ion can thereby be increased without reducing the captured ions by introducing new ions additionally, and signal strength in one time mass spectrometry can be increased by performing mass separation/detection subsequently. Consequently, the number of repeating times of mass spectrometry for integrating the mass profile is decreased and the signal strength can be increased while shortening the measuring time.