Nanostructured silicon field emitter array-based high-vacuum magnetic-less ion pump for miniaturized atomic spectroscopy sensors

We report the design, fabrication, and characterization of a novel magnetic-less ion pump architecture for generation and maintenance of high vacuum in small systems that is compatible with alkali-vapor cells for laser-cooled atomic sensors. The pump uses a nanostructured silicon field emitter array to generate a beam of electrons that fragments the gas molecules into ions, which are captured by a high-voltage getter. In a proof-of-concept demonstration with a 200 cm³ vacuum chamber, pressures as low as 3.0×10^-7 Torr were generated, corresponding to a 25% decrease of the pressure inside the chamber. The field emission cathode does not degrade when operated in the presence of rubidium vapor at a pressure as high as 7×10^-6 Torr, making the pump technology compatible with laser-cooled alkali atom clocks and inertial sensors.