Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.