Multichannel transport of ions into a mass spectrometer vacuum system

• Main Authors: JOCHEN FRANZEN, CHRISTIAN GEBHARDT, ANDREAS BREKENFELD
• Format: Patent
• Language: English
• Published: 30.08.2006
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

The invention relates to methods and devices for the transport of ions generated in gases near atmospheric pressure into the vacuum system of a mass spectrometer. Instead of the single capillary customary in commercial instruments, the invention uses a multichannel plate with hundreds of thousands of very short and narrow capillaries, whose total gas throughput is no higher than that of a normal single capillary. The large-area take-up of ions in the gas flow greatly increases the transfer yield. If the channels are conductive, this prevents the inside surfaces becoming charged. An ion funnel can separate the ions from the gas flow in the vacuum and focus them. Gas-dynamic focusing in an electric decelerating field reduces ion losses caused by wall collisions and prevents very light ions (protons, water clusters) from entering the vacuum. Staged multichannel plates reduce pumping requirements.