Patent ID: 10062558

Abstract:
A technique for improving the efficiency of injecting ions into the electrode unit of a funnel structure having high ion-transport efficiency is provided to improve the overall ion-transport efficiency. From an ionization chamber 1 for ionizing a sample under atmospheric pressure, ions are injected through a straight capillary pipe 3 into the inner space of the electrode unit 10 of a funnel structure composed of ring electrodes in a first intermediate vacuum chamber 4. The space for setting the capillary pipe 3 is formed by replacing one or more ring electrodes with C-shaped electrodes whose circumference portion is partially removed. Each C-shaped electrode is arranged so that the ions will be injected perpendicularly to the ion-transport direction. The injected ions lose energy due to collision cooling, become converged onto the ion-beam axis C due to the ion-confining effect of a radio-frequency electric field, and efficiently move toward the exit aperture along a potential gradient created by a direct-current electric field. The gas stream carrying the ions passes through the gaps of the ring electrodes, without increasing the gas pressure at the exit of the ring-electrode inner space and thereby deteriorating the degree of vacuum in the next stage.