Ion source including an electric discharge chamber body divided by a partition, having an anode electrode therein, into a main discharge chamber and a subsidiary discharge chamber. The subsidiary discharge chamber has a filament mounted therein aligned with at least one small opening through the partition wall and the anode electrode. An inert gas opening is provided into the subsidiary discharge chamber. An electric discharge gas opening and an ion outlet opening are provided to the main discharge chamber. Magnets are provided outside of the chamber body for creating a magnetic field extending nearly along an axis of the at least one small opening in the anode electrode.

Double-chamber ion source

A Freeman type electron bombardment ion source includes dual filament electrodes positioned in an arc chamber having a slit for extraction of an ion beam. The filament electrodes are symmetrically positioned with respect to the extraction slit. The filament electrode currents are equal in magnitude and oppositely directed. As a result, lateral magnetic fields in the region of the extraction slit are substantially eliminated.

Dual filament ion source with improved beam characteristics

An improved ion source is provided with multiple filaments and wiring for selectively connecting various combinations of filaments to a current source. In one embodiment an additional filament is a spare filament which is connected to the current source when the primary filament burns out. This decreases down time due to filament replacement. In another embodiment, an additional filament operates simultaneously with a primary filament to provide a more homogenous electron cloud and to increase filament life.

Multiple filament enhanced ion source

A method and apparatus for operating a multi-hot-cathode ionization gauge is provided to increase the operational lifetime of the ionization gauge in gaseous process environments. In example embodiments, the life of a spare cathode is extended by heating the spare cathode to a temperature that is insufficient to emit electrons but that is sufficient to decrease the amount of material that deposits on its surface or is optimized to decrease the chemical interaction between a process gas and a material of the at least one spare cathode. The spare cathode may be constantly or periodically heated. In other embodiments, after a process pressure passes a given pressure threshold, plural cathodes may be heated to a non-emitting temperature, plural cathodes may be heated to a lower emitting temperature, or an emitting cathode may be heated to a temperature that decreases the electron emission current.

Method and apparatus for maintaining emission capabilities of hot cathodes in harsh environments

A method includes providing an electron gun having a first head with a thermionic electron source and an accelerating electrode, and further includes replacing the first head with a second head having a power rating substantially different than that of the first head, and subsequently operating the electron gun without replacing the accelerating electrode. The electron gun may further include a platform spaced apart from the accelerating electrode and having an adjustably located locating member that engages a reference member on the head to position the head in three dimensions relative to the accelerating electrode. The platform may be adjustably spaced from the accelerating electrode in order vary the distance between the electron source and the accelerating electrode.

Method and apparatus for use an electron gun employing a thermionic source of electrons

An electron bombardment ion source of the Freeman type incorporates an electrode having multiple segments which are electrically connected in parallel to provide increased surface area for constant cross section.

Charles R. Kalbfus

Papers

Dual filament ion source