# US 2017/0287671 A1 · Angled Flat Emitter For High Power Cathode With Electrostatic Emission Control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0287671 A1 - Document ID: US20170287671A1 - Status: Published application - Kind: A1 - Application number: 15/086,257 - Filed: 2016-03-31 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Sergio Lemaitre - Web page: https://patentgrep.com/patent/US20170287671A1 ## CPC - H01J 35/06: Cathodes - H01J 35/065: {Field emission, photo emission or secondary emission cathodes} - A61B 6/032: {Transmission computed tomography [CT]} - H01J 35/045: {Electrodes for controlling the current of the cathode ray, e.g. control grids} - H01J 35/147: {Spot size control} - A61B 6/40: Arrangements for generating radiation specially adapted for radiation diagnosis - A61B 6/56: {Details of data transmission or power supply, e.g. use of slip rings} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract In the present invention, a computed tomography system, an X-ray tube used therein and a cathode assembly disposed in the X-ray tube, as well as an associated method of use, is provided that includes a gantry and the X-ray tube coupled to the gantry. The X-ray tube includes the cathode assembly having a pair of emitters for generating an electron beam, where the pair of emitters are disposed in the casing at angles with respect to one another. The X-ray tube further includes a focusing electrode for focusing the electron beam, an extraction electrode which electrostatically controls the intensity of the electron beam, a target for generating X-rays when impinged upon by the electron beam and a magnetic focusing assembly located between the cathode assembly and the target for focusing the electron beam towards the target. ## Claims ### Claim 1 A cathode assembly for an X-ray tube, the cathode assembly comprising: at least two emitters disposed at an angle relative to one another, each emitter configured to emit an electron beam therefrom. ### Claim 2 (depends on 1) The cathode assembly of claim 1, wherein the angle is in the range of 4 to 12 degrees. ### Claim 3 (depends on 1) The cathode assembly of claim 1, wherein the at least two emitters comprises a pair of flat emitters. ### Claim 4 (depends on 1) The cathode assembly of claim 1, wherein the at least two emitters do not include a septum between the emitters. ### Claim 5 (depends on 1) The cathode assembly of claim 1, wherein at least a portion of the at least two emitters is curved. ### Claim 6 An X-ray tube comprising: a cathode assembly comprising at least two emitters disposed at an angle relative to one another, each emitter configured to generate an electron beam; a focusing electrode adjacent the cathode assembly for focusing the electron beams; an extraction electrode spaced from the focusing electrode opposite the cathode assembly for controlling the intensity of the electron beams; a magnetic assembly spaced from the extraction electrode opposite the focusing electrode; and a target spaced from the magnetic assembly opposite the extraction electrode. ### Claim 7 (depends on 6) The X-ray tube of claim 6 wherein an electric field is generated between the focusing electrode and the extraction electrode which controls the intensity of the electron beams. ### Claim 8 (depends on 6) The X-ray tube of claim 6 wherein the magnetic assembly comprises one or more multipole magnets. ### Claim 9 (depends on 8) The X-ray tube of claim 8, wherein the one or more multipole magnets comprise one or more quadrupole magnets, one or more dipole magnets, or combinations thereof. ### Claim 10 (depends on 6) The X-ray tube of claim 6, wherein an intensity of the electron beams is controlled via an electric field generated between the focusing electrode and the extraction electrode. ### Claim 11 (depends on 6) The X-ray tube of claim 6, wherein the at least two emitters do not include a septum between the emitters. ### Claim 12 (depends on 6) The X-ray tube of claim 6, wherein the extraction electrode is spaced from about 20 mm to about 40 mm from the magnetic assembly. ### Claim 13 A method for focusing an electron beam emitted from an X-ray tube, the method comprising the steps of: providing an X-ray tube including a cathode assembly in which is disposed at least two emitters disposed at an angle relative to one another, each emitter configured to generate an electron beam therefrom, a focusing electrode adjacent the cathode assembly, an extraction electrode spaced from the focusing electrode opposite the cathode assembly, a magnetic assembly spaced from the extraction electrode opposite the focusing electrode and a target spaced from the magnetic assembly opposite the extraction electrode capable of generating X-rays when impinged upon by the electron beams; passing an emission current through at least one of the emitters to generate an electron beam; and passing a focusing current through the magnetic assembly to focus the electron beam onto the target. ### Claim 14 (depends on 13) The method of claim 13, wherein the emission current is between 0.5 A to 2 A. ### Claim 15 (depends on 13) The method of claim 13, wherein the emission current is between 1 A to 2 A. ### Claim 16 (depends on 13) The method of claim 13, further comprising the step of applying a biasing voltage to the extraction electrode to control the intensity of the electron beams. ### Claim 17 (depends on 13) The method of claim 13, wherein the at least two emitters comprises a pair of flat emitters. ### Claim 18 (depends on 13) The method of claim 13, wherein the step of passing the emission current through at least one of the at least two emitters comprises simultaneously passing the emission current through at least two of the at least two emitters. ### Claim 19 A computed tomography system, comprising; a gantry; an X-ray tube coupled to the gantry, the X-ray tube including a cathode assembly comprising at least two emitters for generating an electron beam, the emitters disposed therein at an angle with respect to one another, a focusing electrode for focusing the electron beam; an extraction electrode which controls the intensity of the electron beam; a target for generating X-rays when impinged upon by the electron beam; a magnetic assembly located between the cathode assembly and the target for focusing the electron beam towards the target; an X-ray controller for providing power and timing signals to the X-ray tube; and one or more detector elements for detecting attenuated X-ray beam from an imaging object. ### Claim 20 (depends on 19) The system of claim 19 wherein the at least two emitters comprises a pair of flat emitters.