Compact electrostatic ion pump

A system, comprising:

• an electron source configured to inject electrons;
• an electrode assembly coupled to the electron source, wherein the electrode assembly comprises:
• an outer electrode defining an inner volume and a central axis extending from a top of the outer electrode to a bottom of the outer electrode, wherein the outer electrode is configured to receive injected electrons through at least one aperture, and wherein the outer electrode comprises a wall defining an inner surface curved toward the central axis near the top and the bottom of the outer electrode;
• the at least one aperture being disposed on a curved portion of said inner surface curved toward the central axis;
• and
• an inner electrode positioned in the inner volume,
• wherein the electrode assembly is configured to electrostatically confine the electrons within an internal volume defined by the electrode assembly,
• wherein the outer electrode and inner electrode are configured to electrostatically confine the received electrons in orbits around the inner electrode in response to an electric potential between the outer electrode and the inner electrode,
• wherein the electron source is coupled to the electrode assembly and configured to inject the electrons through the at least one aperture, and
• wherein the system does not include a component configured to generate an electron-confining magnetic field.

A method, comprising:

• receiving, by an ion pump and from an electron source, electrons through at least one aperture, wherein the ion pump comprises:
• an outer electrode defining an inner volume and configured to receive injected electrons through the at least one aperture, wherein the outer electrode comprises a wall defining an inner surface, and wherein a diameter of the inner surface at an axial middle of the outer electrode is greater than each of a diameter of the inner surface at a top of the outer electrode and a diameter of the inner surface at a bottom of the outer electrode;
• the at least one aperture being disposed on a curved portion of said inner surface curved toward the central axis;
• and
• an inner electrode positioned in the inner volume;
• and
• creating, by the ion pump, an electric potential between the outer electrode and the inner electrode,
• wherein the electric potential is configured to confine the electrons in orbits around the inner electrode, and
• wherein the ion pump does not include a component configured to generate an electron-confining magnetic field.