A Micromachined Magnet-Less RF Electron Trap

This paper reports a magnet-less enhanced-efficiency electron trapping module (E
³
TM) that uses micromachined components to provide electron trapping using only RF electric fields. The structure of the E
³
TM is comprised of five microfabricated elements that include two perforated electrodes. Importantly, the electrode perforations are only 130 μm in diameter in order to control the fringing electric field near the electrodes. The microfabricated elements enable a large volume efficiency, with the device occupying a volume of 1.63 cm
³
, of which 75.7% is available for the trap. The electron density as measured by proxy with a small probe near the center of the RF electron trap is approximated as 2.24×10
⁶
cm
^-3
when the E
³
TM is tuned to and operated at 96.9 MHz, and is approximated as 2.16 × 10
⁶
cm
^-3
when tuned to and operated at 141.3 MHz. This trap could potentially be used to enable a magnet-less ion pump for maintaining ultra-high vacuum in chip-scale atomic clocks or other atomic microsystems that are sensitive to magnetic fields.