METHOD AND APPARATUS FOR IMPROVED SENSITIIVITY IN A MASS SPECTROMETER

摘要

An ion source and an ion guide chamber are provided. The ion guide chamber having a gas flow, the gas flow having a longitudinal velocity and a transverse velocity. The ion guide chamber having an exit aperture and at least one ion guide. The at least one ion guide having an entrance end and an exit end with an exit cross-section wherein the exit cross-section is sized to be smaller in area than the entrance cross-section. The at least one ion guide having a plurality of elongated electrodes wherein a gap between the elongated electrodes and the shape of the elongated electrodes in the vicinity of the gap are essentially the same along the length of the at least one ion guide for confining the ions in the vicinity of the gap by a combination of the transverse velocity of the gas and the RF voltage.

主权项

1. A mass spectrometer comprising:
an ion source for generating a beam of ions; an ion guide chamber for receiving the ions from the ion source, the ion source chamber having a gas flow wherein the ions are entrained in the gas flow, the gas flow having a longitudinal velocity and a transverse velocity; the ion guide chamber further comprising an exit aperture for passing the ions from the ion guide chamber; at least one ion guide located in the ion guide chamber, the at least one ion guide having an entrance end and a predetermined entrance cross-section defining an internal volume; the at least one ion guide having an exit end and an exit cross-section wherein the exit cross-section is sized to be smaller in area than the entrance cross-section; a power supply for providing an RF voltage to the at least one ion guide; and the at least one ion guide comprising at least one multipole ion guide having a plurality of elongated electrodes wherein a gap between the elongated electrodes and the shape of the elongated electrodes in the vicinity of the gap are essentially the same along the length of the at least one ion guide for confining the ions in the vicinity of the gap by a combination of the transverse velocity of the gas and the RF voltage.