Multichannel transport of ions into the vacuum system of a mass spectrometer

• Main Authors: JOCHEN FRANZEN, CHRISTIAN GEBHARDT, ANDREAS BREKENFELD
• Format: Patent
• Language: English
• Published: 30.09.2009
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

The invention relates to the transport of ions generated in gases near atmospheric pressure into the vacuum system of a mass spectrometer. The invention uses a multichannel plate 4 with hundreds of thousands of very short and narrow microchannels, whose total gas throughput is no higher than that of a conventional single capillary. The large-area take-up of ions in the gas flow greatly increases the transfer yield. Providing the microchannels with a resistive coating prevents the inside surfaces becoming charged and allows uniform potential gradients to be generated, thereby allowing gas-dynamic focusing of ions in an electric decelerating field. An ion funnel 5 can separate the ions from the gas flow in the vacuum and focus them. Preferably at least two multichannel plates are provided one behind the other, from between which gas may be evacuated at an intermediate pressure. Staged multichannel plate arrangements of this type reduce pumping requirements.