USA As Represented by Secretary of the Navy

The United States of America

Steven H Gold

Arne W Fliflet

David Lewis, Iii

Ralph W Bruce

Phillip A Sprangle

Antonio C Ting

Manfred Kahn

Daniel F Gordon

Bahman Hafizi

Victor L Granatstein

Lynn K Kurihara

Joseph R Penano

Henry Philip Freund

Avraham Gover

An electron injector including an electron source and a conducting grid situated close to the electron source, one or more RF accelerating/bunching cavities operating at the same fundamental RF frequency; a DC voltage source configured to bias the cathode at a small positive voltage with respect to the grid; a first RF drive configured to apply an RF signal between the cathode and grid at the fundamental and third harmonic RF frequencies; and a second RF drive configured to apply an RF drive signal to the accelerating/bunching cavities. Electrons are emitted by the cathode and travel through the grid to the accelerating/bunching cavities for input into an RF linac. The first RF drive applies a first RF drive signal at the fundamental frequency of the linac plus higher harmonics thereof to the gap between the cathode and the grid to cause the emitted electrons to form electron bunches and the second RF drive applies a second RF drive signal to the accelerating/bunching cavities on the other side of the grid to further accelerate and optimize the size of the electron bunches. Because the applied RF signals contain at the fundamental linac frequency, the electrons are bunched at that frequency and each RF bucket of the linac is filled with an electron bunch.

High average current, high quality pulsed electron injector

A method for joining similar materials to create multi-component assemblies so the joint materials share similar physical, chemical, and electrical characteristics with the base materials. The method includes aligning the materials, applying joining material, focusing a microwave beam on the joint area to initially heat the joint area to allow the joining material to soften and fill physical discontinuities while the surrounding surfaces remains cool, rapidly heating the joint area to the reactive area of the joining material, rapidly cooling the joint area and maintaining the joint area at a recrystallization temperature. The materials can be ceramics such as aluminum oxide.

Microwave assisted reactive brazing of ceramic materials

A method of forming a nanocrystalline metal, comprising the steps of: providing a reaction mixture comprising a metal precursor and an alcohol solvent; continuously flowing the reaction mixture through a reactor; applying microwave or millimeter-wave energy to the reaction mixture; wherein the microwave or millimeter-wave energy is localized to the vicinity of the reaction mixture; and heating the reaction mixture with the microwave or millimeter-wave energy so that the alcohol solvent reduces the metal precursor to a metal; wherein the heating occurs in the reactor.

Microwave assisted continuous synthesis of nanocrystalline powders and coatings using the polyol process

A high power, highly efficient, phase-stable frequency-multiplying magnicon microwave amplifier is disclosed having efficiencies that exceed 60%. The magnicon amplifier has an output cavity that receives an electron beam that is deflection modulated by the drive, gain and penultimate cavities of the magnicon amplifier. The output cavity is dimensioned so as to operate in a TM.sub.m10 mode, where m is an even integer greater than two. The output cavity is selected to preferably have an operating frequency f.sub.o which is twice the cyclotron frequency f.sub.c of the output cavity.

Magnicon amplifier operated at the second harmonic of the cyclotron

A gyroklystron device includes an electron beam source, a plurality of bunching cavities and an output cavity. A first bunching cavity has an input coupling aperture for receiving an rf signal from an rf signal injecting source. Each of the bunching cavities has a first pair of substantially uniform-angle slots of a preselected angle, which are diametrically opposed, and extend axially, parallel to the direction of the electron beam and extend into drift regions on both sides of the cavities. The first pair of slots control the Q of a desired mode and higher order modes. A second and third pair of slots are diametrically opposed and extend axially, parallel to the direction of the first pair of slots, but are rotated 90 degrees circumferentially from the first pair of slots. These slots control the axial profile of any mode that leaks out beyond the desired mode and control the length of field interaction with the electron beam. The second and third pair of slots begin in the walls of drift regions just beyond the first pair of slots, and have a preselected angle at their beginning and the angle increases in size along an axial distance away from the cavities. An outer vacuum jacket lined with rf absorbing material is also included such that rf energy leaving through the slots will not return.

Gyroklystron device having multi-slot bunching cavities

A free electron laser for use with a short-pulse relativistic electron source. The device includes a resonant optical cavity in which a spatially-periodic magnetic field is produced by a wiggle magnet assembly. An input optical beam having a wavelength lying within the gate bandwidth of the free electron laser interaction is injected into the cavity. A beam of relativistic electrons produced by a short-pulse source, such as an RF-linac, is injected into the cavity. The electron beam and the input optical beam interact under the influence of the magnetic field to amplify the input optical beam.

Free electron laser injection oscillator

A microwave circular polarizer having two matched waveguide arms with a first arm having a twist in a first rotational sense and with a second arm having a twist in a second (reverse) rotational sense, and a hybrid coupler receiving radiation signals from the two arms. A left-hand 45.degree. twist in one arm and a right-hand 45.degree. twist in the other arm ensure that orthogonal linearly polarized components of an incident radiation field are combined in the hybrid coupler so as to direct a right circularly polarized signal out of one of the remaining ports of the hybrid coupler, and to direct a left circularly polarized signal from the other remaining port of the hybrid coupler.

Microwave circular polarization analyzer

A free electron laser for emitting coherent radiation. The laser includes a wiggler magnet for producing a spatially periodic magnetic field in a drift region into which relativistic electrons are injected in a predetermined direction. An axial magnet is provided which generates an axial magnetic field parallel to the above predetermined direction. The axial field is tapered in field strength within a uniform wiggler region, wherein the wiggler field is of uniform and constant magnitude, such that the tapered field acts to oppose the change in axial electron velocity resulting from the free electron laser interaction as electrons travel through the drift region. The tapered axial field acts to enhance power output and efficiency.

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New Carrollton, MD, United States of America

Steven H Gold