Varian Medical Systems, Inc.

Varian Associates, Inc.

Varian Medical Systems Technologies, Inc.

Clifford K Nishimoto

Gary Fredric Virshup

David H Humber

Stephen G Bandy

Paul D Moore

Michael C Green

James Russell Boye

Steve Bandy

Ross A LaRue

Christopher Webb

Steve G Bandy

Embodiments include an X-ray cathode filament, filament system, process to manufacture the filament and process to use the filament, where the filament includes a planar substrate, such as of tungsten, having a top surface coated with a coating of carburized tungsten (e.g., WC) and thoria (ThO). A first electron beam is emitted from the coating through a thermionic effect at a first temperature, such as when the filament is heated to between 1700 and 1900 degrees Celsius by running an electrical current through the filament. At this temperature, a second electron beam may be caused by (1) a reaction that includes creating thorium (Th) in the coating, and (2) the thorium diffusing to uncoated surfaces of the substrate from which the second electron beam is emitted. The filament may also have slots forming a zipper shape, forming a square switchback shape, or forming a rectangular labyrinth shape to reduce the current required to heat the filament.

Filament for X-ray cathode

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 integrated bearing assembly is provided, comprising a bearing housing defining an axial cavity in which a shaft is disposed. The shaft is rotatably supported by at least two bearing sets. The axial cavity defines three regions, each having distinct diameters. A pair of first regions defines cavity diameters sufficient to receive the bearing sets. A pair of second regions defines cavity diameters such that a small gap is defined between the inner surface of the cavity and the shaft. The third region cooperates with the shaft to define a cylindrical volume containing a coolant. Wettable coatings are utilized in the cylindrical volume to allow free flow of, and maximum contact with, the coolant. Non-wettable coatings are provided in the second regions to contain the coolant. The second regions also function as bearing spacers, thus simplifying bearing assembly design, assembly, and performance.

Integrated bearing assembly

A field emission device (100) uses single crystals in order to eliminate grain boundaries within some or all of the electrodes (103, 104, and 205). The elimination of grain boundaries reduces susceptibility to damage, improves stability of the device (100), and improves uniformity and reproducibility among devices. In a preferred embodiment, the emitter and gate electrodes (103 and 104 respectively) are formed from a single crystal thin film (302). In other embodiments, other structures are employed wherein one or more of the electrodes (103, 104, and 205) are formed from single crystals.

Growing community of inventors

San Jose, CA, United States of America

Clifford K Nishimoto