A NEW AND SIMPLE TIME-OF-FLIGHT MASS FILTER FOR CW ION SOURCES

A mechanically and electronically simple device for recording time-of-flight mass spectra with continuous (cw) ion sources is demonstrated. The principle of operation involves modulation of a cw ion beam by manipulation of beam energy as opposed to deflection across an aperture. The technique works by tagging pulses of ions within a cw ion beam with higher beam energy and separating them from the cw ion beam by virtue of their higher beam energy. Configurations as a mass filter or to record time-of-flight spectra in real time are reported. The technique might find use for mass analysis at the end of an existing cw ion beam or to produce a high-frequency, high-intensity, mass selected, pulsed ion beam at a short distance from a cw ion source.