Abstract: An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.

Abstract: A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

Abstract: A novel design scheme for the compensation circuitry of solid-state Marx modulators has been described for enhancing the compensation ability of the compensation cells of solid-state Marx modulators and simplifying the entire circuitry of the modulator. High-speed solid-state switches are adopted in the new compensation cell for the control of the compensation actions. Inductive components and diodes are adopted in the design scheme to smooth the flattop of the voltage pulse output by the Marx modulator.

Abstract: A photoelectron linear accelerator for producing a low emittance polarized electron beam. The linear accelerator includes a tube having a cylindrical wall, said wall being perforated to allow gas to flow to a pressure chamber containing ultra high vacuum pumps located outside the accelerator. The RF accelerator cavity comprises of two concentric cylindrical regions having different outside diameters and different lengths.

Abstract: A novel design scheme for the compensation circuitry of solid-state Marx modulators has been described for enhancing the compensation ability of the compensation cells of the Marx modulators and simplifying the entire circuitry. High-speed solid-state switches are adopted in the compensation circuitry for the control of the compensation actions. Inductive components and diodes are used in the design scheme to smooth voltage curve.

Abstract: A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

Abstract: A pulse source generates both terahertz radiation (T-rays) and X-rays consecutively at high peak intensity using the same electron beam generated in an RF photoinjector and two different extractors/radiators for the T- and X-rays.

Abstract: A pulse source generates both terahertz radiation (T-rays) and X-rays consecutively at high peak intensity using the same electron beam generated in an RF photoinjector and two different extractors/radiators for the T- and X-rays.

Abstract: A sub-mm wave source based on Cherenkov resonant radiation of a microbunched electron beam radiating coherently in a dielectric-loaded pipe. The microbunched electron beam is produced in a pulse photoinjector by illuminating a metal photocathode with sub-ps or multi-ps intensity-modulated laser beam with a beat wave or multiplexing at terahertz frequencies, the photoelectrons generated at the photocathode being accelerated by an electric field and sub-wavelength focused by magnetic field to propagate through a resonant radiator comprising a corrugated wall or smooth-wall metal capillary pipe internally coated with dielectric and attached to an antenna.

Abstract: A sub-mm wave source based on Cherenkov resonant radiation of a microbunched electron beam radiating coherently in a dielectric-loaded pipe. The microbunched electron beam is produced in a pulse photoinjector by illuminating a metal photocathode with sub-ps or multi-ps intensity-modulated laser beam with a beat wave or multiplexing at terahertz frequencies, the photoelectrons generated at the photocathode being accelerated by an electric field and sub-wavelength focused by magnetic field to propagate through a resonant radiator comprising a corrugated wall or smooth-wall metal capillary pipe internally coated with dielectric and attached to an antenna.

Abstract: A device for generating a plurality of laser pulses from a recirculating single laser pulse in an optical delay line that is capable of partially transmitting the trapped pulse out of the delay line. The energy of the partially reflected trapped pulse is restored before beginning another round trip in the delay line. The time structure of an output pulse train thus generated by the device comprises a sequence of macro pulses, each comprising a plurality of micro pulses.

Abstract: A coupler for converting rf power traveling in the TM01 mode in a circular waveguide to the TE10 mode in a rectangular waveguide. The circular waveguide has an extension comprising an evanescent tube through the coupler allowing the propagation of a particle beam but disallowing the propagation of rf wave in the tube.

Abstract: This invention relates to radiofrequency (rf) cavities and couplers that comprise metallic or dielectric rods to provide specified concentration of field patterns for the operating modes in the interaction region, for applications in particle accelerators, pulsed rf power sources, amplifiers, mode converters and power couplers.

Abstract: A photoelectron linear accelerator for producing a low emittance polarized electric beam. The accelerator includes a tube having an inner wall, the inner tube wall being coated by a getter material. A portable, or demountable, cathode plug is mounted within said tube, the surface of said cathode having a semiconductor material formed thereon.

Abstract: A photoelectron linear accelerator for producing a low emittance polarized electron beam. The linear accelerator includes a tube having an inner wall, the inner tube wall being coated by a getter material. A portable, or demountable, cathode plug is mounted within said tube, the surface of said cathode having a semiconductor material formed thereon.

Abstract: A compact high energy photoelectron injector integrates the photocathode directly into a multicell linear accelerator with no drift space between the injection and the linac. High electron beam brightness is achieved by accelerating a tightly focused electron beam in an integrated, multi-cell, X-band rf linear accelerator (linac). The photoelectron linac employs a Plane-Wave-Transformer (PWT) design which provides strong cell-to-cell coupling, easing manufacturing tolerances and costs.

Abstract: A device which improves the electrical and thermomechanical performance of an RF cavity, for example, in a disk-loaded accelerating structure. A washer made of polycrystalline diamond is brazed in the middle to a copper disk washer and at the outer edge to the plane wave transformer tank wall, thus dissipating heat from the copper disk to the outer tank wall while at the same time providing strong mechanical support to the metal disk. The washer structure eliminates the longitudinal connecting rods and cooling channels used in the currently available cavities, and as a result minimizes problems such as shunt impedance degradation and field distortion in the plane wave transformer, and mechanical deflection and uneven cooling of the disk assembly.

Abstract: A planar RF accelerating structure for charged particles preferably wherein the accelerating field is independent of the transverse position of the particle beam. In a first embodiment, the RF structure has a "tugboat" design to provide a capacitive loading effect; in a second embodiment, the structure has a "barbell" shape to provide an inductive loading effect. In both configurations, the axial electric field is substantially constant, or assumes a prescribed profile other than the typical half-sine distribution of a conventional rectangular cavity.

Abstract: A device for maintaining a high-energy laser pulse within a recirculating optical delay line for a period time to optimize the interaction of the pulse with an electron beam pulse train comprising closely spaced electron micropulses. The delay line allows a single optical pulse to interact with many of the electron micropulses in a single electron beam macropulse in sequence and for the introduction of additional optical pulses to interact with the micropulses of additional electron beam macropulses.

Abstract: A digital-to analogue converter for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration.