Development of a miniature time-of-flight mass/charge spectrometer for ion beam source analyzing

Abstract

To diagnose the vacuum arc discharge process, a miniature time-of-flight mass spectrometer (TOF MS) with compact structure was developed for cathodic vacuum arc discharge ion source. An orthogonal acceleration region and an angle reflector were employed for the miniature TOF MS instrument. Especially, a small extraction hole in the acceleration region was set for getting relative high mass resolution, an ion detector with a large rectangular effective area were designed for getting wide ion kinetic energy distribution measurement capability. The compact size of the TOF MS is 413mm×250mm×414mm, the mass resolution is 600 (FWHM) and the detection range of ion kinetic energy is two orders of magnitude. A copper cathodic vacuum arc discharge ion source was tested and the charge states of Cu ions from 1+ to 3+ were detected. The miniature TOF MS was successfully developed with relative high mass resolution and wide ion kinetic energy distribution measurement capability which could be used to diagnose the cathodic vacuum arc discharge plasma.