Radiofrequency Mass Spectrometer

Abstract

A mass spectrometer tube using velocity selection is described. The tube has parallel plane grids made with knitted wire nets with a large percentage of open area. The grids are arranged in groups of three, and radiofrequency alternating potential is applied to the middle grid of each group. Stopping potentials are used to turn back all ions except those with the selected mass. The spectrometer has sufficient resolution for ordinary gas analysis requirements and is simpler, more compact, and more rugged than magnetic beam deflection devices.