Varian Medical Systems, Inc.

Varex Imaging Corporation

Varian Medical Systems Technologies, Inc.

Paul D Moore

Gary Fredric Virshup

David H Humber

Clifford K Nishimoto

Stephen G Bandy

Kasey Otho Greenland

Christopher F Artig

James Russell Boye

Robert C Treseder

David S K Lee

John E Postman

An example embodiment includes a cathode assembly. The cathode assembly includes a cathode head, a filament, a focusing structure, and a non-rectilinear focusing aperture. The cathode head defines a filament slot. The filament is positioned in the filament slot that is capable of emitting electrons by thermionic emission. The focusing structure is positioned at least partially between the filament and an anode. The non-rectilinear focusing aperture is defined in the focusing structure. The non-rectilinear focusing aperture is configured to shape an emission profile of electrons emitted by the filament.

Focusing structures with non-rectilinear focusing apertures

One example embodiment includes methods for making electron emitters. The electron emitter comprises a conductive member that defines a plurality of filament segments that are integral with each other. Each filament segment includes an intermediate portion and an interconnecting portion attached to an adjacent filament segment. The intermediate portions are substantially coplanar with each other and each intermediate portion includes a substantially planar electron emission surface.

Electron emitter and method of making same

One example embodiment includes an electron emitter. The electron emitter comprises a conductive member that defines a plurality of filament segments that are integral with each other. Each filament segment includes an intermediate portion and an interconnecting portion attached to an adjacent filament segment. The intermediate portions are substantially coplanar with each other and each intermediate portion includes a substantially planar electron emission surface.

An electron emitter assembly, and methods of assembly, is disclosed. The emitter assembly includes an electron emitter that is secured to a support device in a manner such that the emitter is substantially thermally isolated from the support device.

Electron emitter apparatus and method of assembly

An electron emitter assembly for use in an x-ray emitting device or other electron emitter-containing device is disclosed. In one embodiment, an x-ray tube is disclosed, including a vacuum enclosure that houses both an anode having a target surface, and a cathode positioned with respect to the anode. The cathode includes an electron emitter assembly for emitting a beam of electrons during tube operation. The electron emitter assembly comprises a refractory metal foil with a plurality of shaped rung structures for emitting an electron beam that maximizes flux while simultaneously focusing the electron beam in two dimensions. Focusing occurs primarily through an electrical field shaped by the electron emitter assembly and through balancing current density, electrical resistance, and heat loss through thermal conduction to control the regions that emit electrons. Furthermore, the refractory metal foil can be configured with a modified work function for preferential electron emission.

Thermionic emitter designed to control electron beam current profile in two dimensions

An electron emitter assembly for use in an x-ray emitting device or other electron emitter-containing device is disclosed. In one embodiment, an x-ray tube is disclosed, including a vacuum enclosure that houses both an anode having a target surface, and a cathode positioned with respect to the anode. The cathode includes an electron emitter having a plurality of substantially parallel emission surfaces that collectively emit a beam of electrons for impingement on the target anode. In one aspect, the plurality of substantially parallel emission surfaces are angled relative focusing region so as to provide a substantially uniform thermal load on the target anode. In another aspect, the electron emitter includes a plurality of cut-outs that accommodate thermal expansion in the plane of the emitter. Accommodating thermal expansion in the plane of the emitter prevents distortions to the emitter that would tend to alter the focusing of the electrons on the target anode. Providing a substantially uniform thermal load on the target anode and preventing thermal distortion of the emitter lead to higher x-ray flux and better focusing for higher quality x-ray images.

Thermionic emitter designed to provide uniform loading and thermal compensation

A composite stator is disclosed for use with rotationally driven apparatus, particularly high voltage x-ray tubes. The composite stator generally comprises a core, a plurality of motor windings, and a retaining band. The core is comprised of two or more core sections having slots defined therein for receiving the motor windings. The motor windings are wound through and between the slots of the core sections, after which the core sections are joined together to form the core. The core sections are maintained in an assembled configuration by the retaining band. The motor windings are interconnected to comprise the electromagnetic pole pairs of the composite stator, thereby allowing the stator to induce the rotation of the rotor assembly of the high voltage x-ray tube.

Growing community of inventors

Salt Lake City, UT, United States of America

Paul D Moore