Miniaturized magnet-less RF electron trap. I. Modeling and analysis

Ionization of trace gases by electron impact followed by ion extraction is an important pumping approach in ultrahigh vacuum (UHV) systems, which operate at nTorr pressure levels. However, pumping efficiency can only be achieved if the lifetime of electrons is sufficiently long to allow ionizing collisions with neutral species. In miniaturized systems, the electron lifetime is limited due to wall collisions. A traditional approach for an extended electron lifetime via trapping uses crossed electric and magnetic fields. These magnetic fields are undesirable in certain miniaturized systems such as atomic clocks. In this paper, the authors report a method and miniaturized structure for electron trapping in UHV conditions, which does not rely on magnetic fields. Electrons from an electron-beam source are transferred through a grid electrode into a central region of the device where they are trapped in lengthened trajectories using applied radio frequency (RF) electric fields. This paper describes analytical a...