Abstract: A high voltage gas switch includes a gas-tight housing containing an ionizable gas at a preselected gas pressure. The gas switch includes a gas-tight housing containing an ionizable gas at a gas pressure selected based upon a Paschen curve for the ionizable gas, where the Paschen curve plots breakdown voltages of the ionizable gas as a function of gas pressure multiplied by grid-to-anode distance, and where values of gas pressure multiplied by grid-to-anode distance increase over at least a portion of the Paschen curve in conjunction with increasing breakdown voltages. The gas switch also includes an anode disposed within the gas-tight housing, a cathode disposed within the gas-tight housing, and a control grid positioned between the anode and the cathode, where the control grid is spaced apart from the anode by a grid-to-anode distance selected based upon a desired operating voltage.

Abstract: A gas switch includes an anode and a cathode spaced apart from the anode, wherein the cathode includes a conduction surface. The gas switch also includes a plurality of magnets arranged to generate a magnetic field that defines an annular path over a portion of the conduction surface at a radial distance from a switch axis, and a control grid positioned between the anode and the cathode. In operation, the control grid is arranged to establish a conducting plasma between the anode and the cathode, wherein, in the presence of the conducting plasma, a voltage drop between the anode and the cathode is less than 150 volts, and wherein the conducting plasma forms a cathode spot that circles the annular path.

Abstract: Embodiments of the present disclosure relate to a spark gap device that includes a first electrode having a first surface and a second electrode having a second surface offset from and facing the first surface. The spark gap device also includes a light source configured to emit light toward at least the first surface such that photons emitted by the light source when the spark gap is operated are incident on the first surface and cause electron emission from the first surface. The light source includes a discharge probe having a third electrode sealed in a tube filled with an inert gas. The spark gap device may not include a radioactive component.

Abstract: An approach is disclosed for generating seed electrons at a spark gap in the absence of 85Kr. The present approach utilizes the photo-electric effect, using a light source with a specific nominal wave length (or range of wavelengths) at a specific level of emitted flux to generate seed electrons.

Abstract: A var compensator circuit is provided. The var compensator circuit includes a gas tube switch and a reactive impedance. The gas tube switch is configured to be coupled to a transmission line. The transmission line is configured to deliver real power and reactive power to a load at an alternating current (AC) line voltage. The reactive impedance is configured to be coupled to the transmission line at the AC line voltage through the gas tube switch. The reactive impedance is configured to modify the reactive power configured to be delivered to the load.

Abstract: A direct current (DC)-DC converter includes a transformer and a gas tube-switched inverter circuit. The transformer includes a primary winding and a secondary winding. The gas tube-switched inverter circuit includes first and second inverter load terminals and first and second inverter input terminals. The first and second inverter load terminals are coupled to the primary winding. The first and second inverter input terminals are couplable to a DC node. The gas tube-switched inverter circuit further includes a plurality of gas tube switches respectively coupled between the first and second inverter load terminals and the first and second inverter input terminals. The plurality of gas tube switches is configured to operate to generate an alternating current (AC) voltage at the primary winding.

Abstract: Embodiments of the present disclosure relate to a spark gap device that includes a first electrode having a first surface and a second electrode having a second surface offset from and facing the first surface. The spark gap device also includes a cantilevered component coupled to the first electrode that is configured to generate a field emission, a corona discharge or both, to emit light toward at least the first surface such that photons are incident on the first surface and cause electron emission from the first surface. The spark gap device may not include a radioactive component.

Abstract: An approach is disclosed for generating seed electrons at a spark gap in the absence of 85Kr. The present approach utilizes the photo-electric effect, using a light source with a specific nominal wave length (or range of wavelengths) at a specific level of emitted flux to generate seed electrons.

Abstract: Embodiments of the present disclosure relate to a spark gap device that includes a first electrode having a first surface and a second electrode having a second surface offset from and facing the first surface. The spark gap device also includes a light source configured to emit light toward at least the first surface such that photons emitted by the light source when the spark gap is operated are incident on the first surface and cause electron emission from the first surface. The light source includes a discharge probe having a third electrode sealed in a tube filled with an inert gas. The spark gap device may not include a radioactive component.

Abstract: Embodiments of the present disclosure relate to a spark gap device that includes a first electrode having a first surface and a second electrode having a second surface offset from and facing the first surface. The spark gap device also includes a cantilevered component coupled to the first electrode that is configured to generate a field emission, a corona discharge or both, to emit light toward at least the first surface such that photons are incident on the first surface and cause electron emission from the first surface. The spark gap device may not include a radioactive component.

Abstract: A var compensator circuit is provided. The var compensator circuit includes a gas tube switch and a reactive impedance. The gas tube switch is configured to be coupled to a transmission line. The transmission line is configured to deliver real power and reactive power to a load at an alternating current (AC) line voltage. The reactive impedance is configured to be coupled to the transmission line at the AC line voltage through the gas tube switch. The reactive impedance is configured to modify the reactive power configured to be delivered to the load.

Abstract: The present approach relates to generating seed electrons at a spark gap in the absence of 85Kr. The present approach utilizes electron emission from a triple-point instead to provide seed electrons to reduce the statistical time lag of a spark gap. In one such implementation, a spark gap a spark gap may be fabricated and/or operated without a radioactive component without otherwise changing its overall form or function of the spark gap.

Abstract: A direct current (DC)-DC converter includes a transformer and a gas tube-switched inverter circuit. The transformer includes a primary winding and a secondary winding. The gas tube-switched inverter circuit includes first and second inverter load terminals and first and second inverter input terminals. The first and second inverter load terminals are coupled to the primary winding. The first and second inverter input terminals are couplable to a DC node. The gas tube-switched inverter circuit further includes a plurality of gas tube switches respectively coupled between the first and second inverter load terminals and the first and second inverter input terminals. The plurality of gas tube switches is configured to operate to generate an alternating current (AC) voltage at the primary winding.

Abstract: A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to “switch on” one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and “switch off” the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

Abstract: In one aspect of the present invention, a photovoltaic device is provided. The photovoltaic device includes a window layer and an absorber layer disposed on the window layer, wherein the absorber layer includes a first region and a second region, the first region disposed adjacent to the window layer. The absorber layer further includes a first additive and a second additive, wherein a concentration of the first additive in the first region is greater than a concentration of the first additive in the second region, and wherein a concentration of the second additive in the second region is greater than a concentration of the second additive in the first region. Method of making a photovoltaic device is also provided.

Abstract: A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to “switch on” one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and “switch off” the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

Abstract: A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to “switch on” a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and “switch off” the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.

Abstract: A cold-cathode switching device is presented. The cold-cathode switching device (100) includes a housing (110) defining a chamber (111); an ionizable gas (112) disposed in the chamber; and a plurality of electrodes (120) disposed in the chamber. The plurality of electrodes includes a cathode (124) and an anode (122) defining a discharge gap, and wherein at least one of the cathode and anode comprises a material (140) that is liquid at an operating temperature of the cathode or the anode.

Abstract: A power converter including at least one switching device is presented. The power converter is configured to convert an input parameter to an output parameter by periodically activating and deactivating the switching device. The switching device includes: (i) a chamber including an ionizable gas; (ii) a cathode and an anode defining a discharge gap disposed in the chamber; (iii) a magnet assembly configured to generate a first magnetic field such that a plasma is maintained in the discharge gap; and (iv) an electromagnet configured to generate, in response to a deactivation signal, a second magnetic field such that at least a portion of the plasma in the discharge gap is disrupted to deactivate the switching device. A method of power conversion and a switching device are also presented.

Abstract: A phase-contrast imaging system and method. An embodiment of the invention includes a plurality of X-ray emitters for transmitting X-rays through an object to a detector. Adjacent X-ray emitters may be activated at different times to prevent confounding of X-ray striking on the detector. Each X-ray emitter can be operated independently to provide different flux outputs for reducing overall patient dose.