Patents by Inventor Stephen E. Sampayan

Stephen E. Sampayan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10270368
    Abstract: A multi-stage electric voltage converter is disclosed. The converter comprises a voltage source and multiple stages. Each stage of the multiple stages comprises a first and a second and a third switch, and a capacitor, wherein the capacitor is coupled to the voltage source by the first and the second switches and each stage is coupled to a different stage or to an output of the multi-stage electric voltage converter by the third switch so as to allow the capacitor to be charged by the voltage source when the first and the second switches are closed and the third switch is open, and to allow the capacitor to be connected to the output of the multi-stage electric voltage converter when the first and the second switches are open and the third switch is closed.
    Type: Grant
    Filed: December 2, 2016
    Date of Patent: April 23, 2019
    Assignee: Lawrence Livermore National Security, LLC
    Inventor: Stephen E. Sampayan
  • Patent number: 10134927
    Abstract: A photoconductive switch consisting of an optically actuated photoconductive material, e.g. a wide bandgap semiconductor such as SiC, situated between opposing electrodes. The electrodes are created using various methods in order to maximize reliability by reducing resistive heating, current concentrations and filamentation, and heating and ablation due to the light source. This is primarily accomplished by the configuration of the electrical contact geometry, choice of contacts metals, annealing, ion implantation, creation of recesses within the SiC, and the use of coatings to act as encapsulants and anti-reflective layers.
    Type: Grant
    Filed: July 8, 2016
    Date of Patent: November 20, 2018
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: Lars Voss, Mihail Bora, George Caporaso, Adam Conway, Hoang T. Nguyen, Rebecca J. Nikolic, Stephen E. Sampayan, Sangtae Park
  • Publication number: 20180159443
    Abstract: A multi-stage electric voltage converter is disclosed. The converter comprises a voltage source and multiple stages. Each stage of the multiple stages comprises a first and a second and a third switch, and a capacitor, wherein the capacitor is coupled to the voltage source by the first and the second switches and each stage is coupled to a different stage or to an output of the multi-stage electric voltage converter by the third switch so as to allow the capacitor to be charged by the voltage source when the first and the second switches are closed and the third switch is open, and to allow the capacitor to be connected to the output of the multi-stage electric voltage converter when the first and the second switches are open and the third switch is closed.
    Type: Application
    Filed: December 2, 2016
    Publication date: June 7, 2018
    Inventor: Stephen E. Sampayan
  • Publication number: 20180013029
    Abstract: A photoconductive switch consisting of an optically actuated photoconductive material, e.g. a wide bandgap semiconductor such as SiC, situated between opposing electrodes. The electrodes are created using various methods in order to maximize reliability by reducing resistive heating, current concentrations and filamentation, and heating and ablation due to the light source. This is primarily accomplished by the configuration of the electrical contact geometry, choice of contacts metals, annealing, ion implantation, creation of recesses within the SiC, and the use of coatings to act as encapsulants and anti-reflective layers.
    Type: Application
    Filed: July 8, 2016
    Publication date: January 11, 2018
    Inventors: Lars Voss, Mihail Bora, George Caporaso, Adam Conway, Hoang T. Nguyen, Rebecca J. Nikolic, Stephen E. Sampayan, Sangtae Park
  • Patent number: 9500601
    Abstract: Apparatus, systems, and methods that provide an X-ray interrogation system having a plurality of stationary X-ray point sources arranged to substantially encircle an area or space to be interrogated. A plurality of stationary detectors are arranged to substantially encircle the area or space to be interrogated, A controller is adapted to control the stationary X-ray point sources to emit X-rays one at a time, and to control the stationary detectors to detect the X-rays emitted by the stationary X-ray point sources.
    Type: Grant
    Filed: March 4, 2014
    Date of Patent: November 22, 2016
    Assignee: Lawrence Livermore National Security, LLC
    Inventor: Stephen E. Sampayan
  • Publication number: 20150187470
    Abstract: A photoconductive switch and optical transconductance varistor having a photoconductive region e.g. a wide bandgap semiconductor material substrate between opposing electrodes. An optical waveguide is arranged to surround the photoconductive region for directing conduction-inducing radiation into the photoconductive region. And an optical diffusion element is arranged to diffuse/disperse the radiation prior to entering the optical waveguide and into the substrate, for uniformly illuminating the substrate for conduction.
    Type: Application
    Filed: March 12, 2015
    Publication date: July 2, 2015
    Inventors: Stephen E. Sampayan, Hoang T. Nguyen, Scott D. Nelson
  • Publication number: 20140270054
    Abstract: Apparatus, systems, and methods that provide an X-ray interrogation system having a plurality of stationary X-ray point sources arranged to substantially encircle an area or space to be interrogated. A plurality of stationary detectors are arranged to substantially encircle the area or space to be interrogated, A controller is adapted to control the stationary X-ray point sources to emit X-rays one at a time, and to control the stationary detectors to detect the X-rays emitted by the stationary X-ray point sources.
    Type: Application
    Filed: March 4, 2014
    Publication date: September 18, 2014
    Inventor: Stephen E. Sampayan
  • Patent number: 8749949
    Abstract: In a structure or device having a pair of electrical conductors separated by an insulator across which a voltage is placed, resistive layers are formed around the conductors to force the electric potential within the insulator to distribute more uniformly so as to decrease or eliminate electric field enhancement at the conductor edges. This is done by utilizing the properties of resistive layers to allow the voltage on the electrode to diffuse outwards, reducing the field stress at the conductor edge. Preferably, the resistive layer has a tapered resistivity, with a lower resistivity adjacent to the conductor and a higher resistivity away from the conductor. Generally, a resistive path across the insulator is provided, preferably by providing a resistive region in the bulk of the insulator, with the resistive layer extending over the resistive region.
    Type: Grant
    Filed: October 31, 2011
    Date of Patent: June 10, 2014
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: George J. Caporaso, Stephen E. Sampayan, David M. Sanders
  • Patent number: 8655125
    Abstract: A photo-conductive switch package module having a photo-conductive substrate or wafer with opposing electrode-interface surfaces, and at least one light-input surface. First metallic layers are formed on the electrode-interface surfaces, and one or more optical waveguides having input and output ends are bonded to the substrate so that the output end of each waveguide is bonded to a corresponding one of the light-input surfaces of the photo-conductive substrate. This forms a waveguide-substrate interface for coupling light into the photo-conductive wafer. A dielectric material such as epoxy is then used to encapsulate the photo-conductive substrate and optical waveguide so that only the metallic layers and the input end of the optical waveguide are exposed. Second metallic layers are then formed on the first metallic layers so that the waveguide-substrate interface is positioned under the second metallic layers.
    Type: Grant
    Filed: June 28, 2011
    Date of Patent: February 18, 2014
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: James S. Sullivan, David M. Sanders, Steven A. Hawkins, Stephen E. Sampayan
  • Patent number: 8563930
    Abstract: A system and method for producing modulated electrical signals. The system uses a variable resistor having a photoconductive wide bandgap semiconductor material construction whose conduction response to changes in amplitude of incident radiation is substantially linear throughout a non-saturation region to enable operation in non-avalanche mode. The system also includes a modulated radiation source, such as a modulated laser, for producing amplitude-modulated radiation with which to direct upon the variable resistor and modulate its conduction response. A voltage source and an output port, are both operably connected to the variable resistor so that an electrical signal may be produced at the output port by way of the variable resistor, either generated by activation of the variable resistor or propagating through the variable resistor. In this manner, the electrical signal is modulated by the variable resistor so as to have a waveform substantially similar to the amplitude-modulated radiation.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: October 22, 2013
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: John Richardson Harris, George J. Caporaso, Stephen E. Sampayan
  • Patent number: 8125089
    Abstract: An improved photoconductive switch having a SIC or other wide band gap substrate material, such as GaAs and field-grading liners composed of preferably SiN formed on the substrate adjacent the electrode perimeters or adjacent the substrate perimeters for grading the electric fields.
    Type: Grant
    Filed: November 23, 2010
    Date of Patent: February 28, 2012
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: George J. Caporaso, Stephen E. Sampayan, James S. Sullivan, David M. Sanders
  • Publication number: 20110101376
    Abstract: An improved photoconductive switch having a SIC or other wide band gap substrate material, such as GaAs and field-grading liners composed of preferably SiN formed on the substrate adjacent the electrode perimeters or adjacent the substrate perimeters for grading the electric fields.
    Type: Application
    Filed: November 23, 2010
    Publication date: May 5, 2011
    Applicant: Lawrence Livermore National Security, LLC
    Inventors: George J. Caporaso, Stephen E. Sampayan, James S. Sullivan, David M. Sanders
  • Patent number: 7893541
    Abstract: An improved photoconductive switch having a SiC or other wide band gap substrate material, such as GaAs and field-grading liners composed of preferably SiN formed on the substrate adjacent the electrode perimeters or adjacent the substrate perimeters for grading the electric fields.
    Type: Grant
    Filed: October 24, 2006
    Date of Patent: February 22, 2011
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: George J. Caporaso, Stephen E. Sampayan, James S. Sullivan, David M. Sanders
  • Patent number: 7710051
    Abstract: A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (˜70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.
    Type: Grant
    Filed: October 24, 2006
    Date of Patent: May 4, 2010
    Assignee: Lawrence Livermore National Security, LLC
    Inventors: George J. Caporaso, Yu-Jiuan Chen, Steven A. Hawkins, Stephen E. Sampayan, Arthur C. Paul
  • Publication number: 20100060207
    Abstract: A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (˜70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.
    Type: Application
    Filed: October 24, 2006
    Publication date: March 11, 2010
    Applicant: The Regents of the University of California
    Inventors: George J. Caporaso, Yu-Jiuan Chen, Steven A. Hawkins, Stephen E. Sampayan
  • Publication number: 20100032580
    Abstract: A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (˜70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.
    Type: Application
    Filed: July 30, 2009
    Publication date: February 11, 2010
    Inventors: George J. Caporaso, Yu-Jiuan Chen, Steven A. Hawkins, Stephen E. Sampayan
  • Publication number: 20090261258
    Abstract: A system and method for producing modulated electrical signals. The system uses a variable resistor having a photoconductive wide bandgap semiconductor material construction whose conduction response to changes in amplitude of incident radiation is substantially linear throughout a non-saturation region to enable operation in non-avalanche mode. The system also includes a modulated radiation source, such as a modulated laser, for producing amplitude-modulated radiation with which to direct upon the variable resistor and modulate its conduction response. A voltage source and an output port, are both operably connected to the variable resistor so that an electrical signal may be produced at the output port by way of the variable resistor, either generated by activation of the variable resistor or propagating through the variable resistor. In this manner, the electrical signal is modulated by the variable resistor so as to have a waveform substantially similar to the amplitude-modulated radiation.
    Type: Application
    Filed: April 17, 2009
    Publication date: October 22, 2009
    Inventors: John Richardson Harris, George J. Caporaso, Stephen E. Sampayan
  • Patent number: 7173385
    Abstract: A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: February 6, 2007
    Assignee: The Regents of the University of California
    Inventors: George J. Caporaso, Stephen E. Sampayan, Hugh C. Kirbie
  • Patent number: 6331194
    Abstract: A method for building hollow insulator cylinders that can have each end closed off with a high voltage electrode to contain a vacuum. A series of fused-silica round flat plates are fabricated with a large central hole and equal inside and outside diameters. The thickness of each is related to the electron orbit diameter of electrons that escape the material surface, loop, and return back. Electrons in such electron orbits can support avalanche mechanisms that result in surface flashover. For example, the thickness of each of the fused-silica round flat plates is about 0.5 millimeter. In general, the thinner the better. Metal, such as gold, is deposited onto each top and bottom surface of the fused-silica round flat plates using chemical vapor deposition (CVD). Eutectic metals can also be used with one alloy constituent on the top and the other on the bottom. The CVD, or a separate diffusion step, can be used to defuse the deposited metal deep into each fused-silica round flat plate.
    Type: Grant
    Filed: July 8, 1997
    Date of Patent: December 18, 2001
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Stephen E. Sampayan, Michael L. Krogh, Steven C. Davis, Derek E. Decker, Ben Z. Rosenblum, David M. Sanders, Juan M. Elizondo-Decanini
  • Patent number: 6278239
    Abstract: A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.
    Type: Grant
    Filed: June 10, 1998
    Date of Patent: August 21, 2001
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: George J. Caporaso, Stephen E. Sampayan, Hugh C. Kirbie