Abstract: A free electron laser (FEL) is disclosed in which the phase of the output electromagnetic beam is inherently adjustable without the use of any extraneous optical phase shifting materials. This is accomplished by implementing the FEL as a pair of series-connected wiggler cavity sections, and varying the relative phases of the bunched electron flow in the first cavity section relative to the second. In a preferred embodiment a series of electrodes are provided in a transition region between the two cavity sections, and variable voltages are applied to the electrodes to electrostatically control the electron transit time through the transition region, and the electron velocity upon exiting from that region. This translates into a control over phase and frequency.

Abstract: A system for instantaneously ionizing and continuously delivering energy in the form of surface waves to a low pressure gas or mixture of low pressure gases, comprising a source of rf energy, a discharge container, (such as a fluorescent lamp discharge tube), an rf shield, and a coupling device responsive to rf energy from the source to couple rf energy directly and efficiently to the gas or mixture of gases to ionize at least a portion of the gas or gases and to provide energy to the gas or gases in the form of surface waves. The majority of the rf power is transferred to the gas or gases near the inner surface of the discharge container to efficiently transfer rf energy as excitation energy for at least one of the gases. The most important use of the invention is to provide more efficient fluorescent and/or ultraviolet lamps.

Abstract: In gyrotron devices, pitch factor and efficiency are directly proportional. When the pitch factor is increased, however, a larger starting current is needed. The available power supply thus limits the pitch factor and subsequently, the efficiency of the device. The present invention is a gyrotron device in which the pitch factor is adjustable. When starting the gyrotron the pitch factor is set to a low level and only a small starting current is required. After the device has been started, the pitch factor can be increased to increase the oscillation efficiency.

Abstract: The magnetomotive force of a current produces a magnetic field in magnetic material which encircles the current. Although magnetic material attracts a current, material having vanes repels the current because of magnetic flux lines produced between the vanes. The magnetic material is symmetrically arranged, and consists of pairs of radial, magnetic vanes connected by a magnetic member encircling the current. The magnetic member has a uniformly-distributed coil whose ampere-turns oppose the magnetomotive force of the current. The number of magnetic members is n. The angular spacing of the vanes equals 180/n. The coil ampere-turns equals l(n-1)/n, where l is the current. The guiding of the current occurs for one-half of the area of the plane on which the magnetic material is located. To obtain guiding for the other half, a second plane has magnetic material similar to that on the original plane, but rotated by the angle 180/n.

Abstract: Certain applications require a CRT display to be well shielded against emitting RF electromagnetic energy. A shield placed at the neck portion of a CRT envelope inhibits RF emissions from being transmitted through the face portion of the CRT. The shield comprises longitudinal conductors for suppressing transverse magnetic (TM.sub.01, TM.sub.02 . . . ) mode emissions and circular conductors for suppressing transverse electric (TE.sub.01, TE.sub.02 . . . ) mode emissions. Placing the shield at the rear of the CRT envelope eliminates the need for covering the face portion of the CRT with an optically transparent screen. To eliminate RF emissions from the CRT display the housing is provided with a contiguous RF emission shield that is connected to the shield on the neck of the CRT. Alternatively, an internal RF emission shield would enclose the video circuitry which includes all potential sources of undesired RF emission.

Abstract: This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles.

Abstract: A sub-nanosecond rise time megavolt pulse generator is disclosed. The generator utilizes an induction energy store together with electron beams for generating a sub-nanosecond high voltage pulse wave-front. The electron beams are deflected to establish the wave-front. In a preferred form multiple electron beams together with a waveguide of particular shape provide simultaneous converging wave-fronts that are directed to a local area.

Abstract: An apparatus and method for generating high power electro magnetic radiation in the millimeter or submillimeter range axial injection and adiabatic compression of an electron beam using large electric fields in an evacuated AXIOM (Axial Injection Orbitron Maser).

Abstract: A device (10) for producing high-powered and coherent microwaves is described. The device comprises an evacuated, cylindrical, and hollow real cathode (20) that is driven to inwardly field emit relativistic electrons. The electrons pass through an internally disposed cylindrical and substantially electron-transparent cylindrical anode (24), proceed toward a cylindrical electron collector electrode (26), and form a cylindrical virtual cathode (32). Microwaves are produced by spatial and temporal oscillations of the cylindrical virtual cathode (32), and by electrons that reflex back and forth between the cylindrical virtual cathode (32) and the cylindrical real cathode (20).

Abstract: A foilless intense relativistic electron beam generator uses an ionized cnel to guide electrons from a cathode passed an anode to a remote location.

Abstract: The present invention provides a vircator with improved efficiency. An elongated anode is aligned with an elongated cathode so as to produce an elongated virtual cathode when a direct current voltage source is electrically connected to the elongated cathode. A surface wave having a velocity near the velocity of light will be produced on the virtual cathode. Waveguide means enclosing the virtual cathode is disposed so as to propagate microwave radiation in a direction parallel to the direction of elongation of the cathode, anode and virtual cathode. The waveguide is designed to match the phase velocity of the microwave to the velocity of the virtual cathode surface wave.

Abstract: An IREB is guided through a curved path by ionizing a channel in a gas with electrons from a filament, and confining the electrons to the center of the path with a magnetic field extending along the path. The magnetic field is preferably generated by a solenoid extending along the path.

Abstract: A method and apparatus are disclosed for producing microwave radiation wherein a generally stable, high-beta, relativistic electron plasma is formed and magnetically confined in a magnetic mirror region of a suitable enclosure, a convectively unstable wave then being created in the confined plasma for producing a pulse of relatively intense microwave radiation at a frequency near a local electron gyrofrequency of the plasma, the plasma preferably being formed by simultaneous multiple-frequency electron cyclotron heating and upper off-resonant heating using microwave power at frequencies above the electron gyrofrequency of the plasma.

Abstract: An external cavity klystron vacuum tube has a ceramic cylindrical wall surrounded by an external cavity within which is an output probe. The cylindrical wall section is sealed at its ends to other components of the tube--to enable the interior to be evacuated--by sealing means such as to avoid a sharp edge projecting inwardly towards the interior of the cavity.

Abstract: An improved radiation source is disclosed, exploiting the spontaneous radiation generated from the interaction of an electron beam and a conductive grating. Conditions are defined for generating coherent or noncoherent radiation, and for extending the tunability of the radiation source from millimeter, IR, visible and UV wavelengths to x-ray wavelengths, and for generating multiple wavelengths simultaneously. Conditions are disclosed for enhancing the intensity of the spontaneous radiation, anf for modulating the radiation.

Abstract: An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Abstract: A device for guiding an electron beam from an electron gun to a microwave resonator in a microwave source operating according to the gyrotron principle, including a beam duct for guiding the electron beam, wherein the beam duct encloses the electron beam and has an electrically highly conductive surface area. For damping unwanted wave modes inside the beam duct, a plurality of damping openings are provided in the surface area of the beam duct. The characteristic aperture size (a) of the damping openings is larger than the wavelength of the modes to be damped. A particularly simple implementation employs wire mesh with an appropriate mesh size used as the material for the surface area of the beam duct.

Abstract: An electron gun for emitting a modulated electron beam. The gun includes an evacuated envelope having an output end with a photocathode positioned in the envelope and responsive to light to emit electrons. An anode is positioned between the photocathode and the output end for accelerating the electrons emitted by the photocathode. The gun further includes a source of potential interconnecting the anode and the photocathode for maintaining the anode electrostatically positive relative to the photocathode. A first laser provides a first laser beam at a first frequency illuminating the photocathode, and a second laser provides a second laser beam at a second frequency illuminating the photocathode at the same time. The first frequency differs from the second frequency by a beat frequency, whereby the photocathode provides the electron beam with the electrons spacially bunched in accordance with the beat frequency. A method of providing a modulated electron beam is also disclosed.

Abstract: A helix type traveling wave tube comprises an evacuated envelope containing an electron gun assembly at one end thereof for forming and projecting a beam of electrons over an elongated beam path to an electron collector electrode at the opposite end of the envelope. A helix slow-wave circuit is arranged along the beam path intermediate the electron gun and the beam collector for electromagnetic interaction with the beam. In order to extract an amplified signal from the downstream end of the slow wave circuit, there is provided an coaxial line including an outer conductor air-tightly fixed at one end thereof to the evacuated envelope and an inner conductor having one end connected to an output end of the slow wave circuit. An output waveguide is air-tightly fixed to the other end of the coaxial line outer conductor in such a manner the other end of the coaxial line inner conductor extending into the output waveguide.

Abstract: A source of coherent radiation. The source includes an evacuated drift tube having an input end for receiving a beam of relativistic electrons and an output end for providing coherent radiation. A relativistic electron supply provides the beam of electrons to the drift tube input end, and a magnetic field is provided for causing the relativistic electrons to spiral. An azimuthal wiggler causes the spiraling electrons to undergo accelerations while an axial magnetic field is provided for controlling the gyroradii of the spiraling electrons acted upon by the wiggler.

Abstract: An ion or electron beam is steered or focussed by a circular magnetic field produced by passing a large electrical current through a straight conducting wire, the magnetic field being co-axial with the wire. Annular beams of charged particles coaxial with the straight wire can be focussed onto a circular spot or, depending upon the entry radius of the annular beam and the magnetic field strength, can be induced to follow a looping trajectory. The effect of the steering or focussing system can be enhanced by the provision of a cylindrical conductor which is co-axial with the straight conducting wire such that the particle beam passes between the wire and the cylindrical conductor. The beam steering or focussing systems is applicable to the fields of beam current density intensification, ion implantation, ion separation and free electron lasers.

Abstract: A coupler employing two similar sections of waveguide which extend coliney in longitudinal succession. Adjacent ends of the guide sections are spaced apart to form a gap in the boundary of the sections. A third section of waveguide is disposed external to and coaxial with at least a part of each of the two waveguide sections to provide a boundary surrounding the gap. Electromagnetic energy propagating down one of the two similar sections of waveguide in a first mode and entering the gap is converted partly to a plurality of other modes. The converted energy is reconverted to the first mode upon reaching the other of the two similar sections of waveguide. The electric field pattern exciting the section of waveguide at the end of the gap and propagating down it is exclusively in the first mode.

Abstract: Four broad metal vanes form two pairs of contoured metal sheets arranged symmetrically about orthogonal planes of a discharge device to provide a uniform and properly shaped electric field for a discharge region between opposed slab electrodes situated between upper and lower pairs of the vanes in proximity to electrode edges. The electrodes border the region inside a housing having dielectric wall portions interposed between broad surface portions of the vanes and the discharge region located intermediate the electrodes. The electric field is delineated by the vanes so as to inhibit discharge tracking on the wall portions bounding the discharge region.

Abstract: A generator of short electromagnetic waves is provided with a novel form of resonant cavity having improved mode selectivity. The reflecting walls of the cavity correspond to a surface of revolution and the meridian planes include four discrete mirror zones which face each other and are positioned so that the centers of the mirror zones form the vertex of a polygon and the normals to said mirror zones at the centers are bisectors of the angles formed at the vertices of the polygon.

Abstract: A generator for producing an intense relativistic electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

Abstract: A spherical RF source tube which requires no magnetic fields for its operation which consists of two concentric spherical shells. The inner shell, which is open and which is nearly transparent to electrons, is charged positively with respect to the grounded outer shell, which is solid. The outer shell contains ports for the vacuum system, for the high voltage bushing that supports the inner shell, for the output coupling devices, and for plasma devices used in starting and maintaining operation.

Abstract: A gyrotron device comprising a magnetron injection gun for emitting a sectionally-ring-shaped electron beam, a superconducting coil for applying magnetic field to the electron beam emitted from the gun, a ring-shaped resonator mirror for quasi-optically reflecting and resonating those electromagnetic waves which are oscillated when the electron beam passes along the magnetic lines of force generated by the superconducting coil and which propagate in the radial direction, while radially emitting a portion of the electromagnetic waves, and a plurality of transmission mirrors for quasi-optically reflecting and transmitting the electromagnetic waves which have been emitted in the radial direction of the resonator mirror.

Abstract: This transformer (9) is formed by a waveguide, of approximately elliptical cross-section, and with increasing eccentricity (e) along the axis (z) of the transformer. This transformer (9) is connected on one side to the cavity (1) of a gyrotron (11) and on the other side to a section of guide (13) having the same cross-section as the final cross-section of the transformer and of which the cross-section is constant along the axis (z) of the transformer.The transformer receives from the gyrotron cavity a complex mode, of TE.sub.on type, and changes said mode into a mode in which the electrical field is approximately parallel to a given direction (z). A system of two mirrors (M.sub.3 and M.sub.4) enables a single beam of plane waves (19) to be obtained from the two beams of plane waves (14 and 15) obtained at the output of the section of waveguide (13).

Abstract: A device for converting the kinetic energy of an intense relativistic electron beam (IREB) into trains of multi-gigawatt AC electrical pulses comprising a foilless diode for generating an IREB and injecting the IREB into one end of a drift tube. The device further includes a modulating circuit for modulating the IREB current while in the drift tube to obtain longitudinally spaced bunches of electrons, and a coaxial transmission line with the end of its center conductor disposed across the other end of the drift tube in the path of the IREB. A gap is disposed between the end of the drift tube and the end of the center conductor. The modulated IREB induces a voltage in the coaxial transmission line. This voltage appears across the gap to slow down the electrons and to convert the kinetic energy of the IREB into electrical energy that propagates along the coaxial transmission line.

Abstract: A novel window assembly with improved cooling capabilities for use in high power microwave tube and waveguide apparatus is disclosed. A septum with a circular central aperture is disposed between two parallel windows. Cooling fluid is circulated in from the periphery of one of said windows, flows toward the central region, through the aperture in the septum, and then out at the periphery of the second of said windows. This arrangement results in an increased cooling fluid velocity thereby increasing the cooling effectiveness of the window assembly. By adding surface features such as bumps, channels and the like to the septum, one can additionally increase local cooling fluid velocity in areas of the window assembly subject to greater localized heating. This is particularly useful in gyrotron tubes, where the energy impinging on the window surface is in the circular-electric-field mode and areas of the window surface are known to be subject to greater thermal stress.

Abstract: A tube for amplifying high-frequency multi-kilowatt, amplitude-modulated signals utilizes a linear beam of electrons which is density-modulated by a permeable control grid spaced close to a thermionic cathode. The beam is focused through a drift tube having two axially spaced gaps, each coupled to a resonant circuit such as a hollow cavity. The first circuit is tuned to a resonant frequency higher than the signal frequency to produce velocity-modulation bunching of the beam electrons in phase with the density-modulation from the grid. The second circuit is tuned to the signal frequency and its energy is coupled out to an external load. The grid modulation is Class B or Class C so there is no current between the electron bunches. The floating bunching circuit can thus, by velocity modulation, produce very dense bunches to excite the output circuit, providing very high conversion efficiency.

Abstract: A cyclotron resonance maser system includes coaxial coupling between coaxial wave guides. Such coupling is provided between an outer coaxial waveguide through which a gyrotron electron beam passes in generating or amplifying microwaves and an inner coaxial waveguide terminating in an annular window. The coupling separates the microwaves from the electron beam before the collector region of the gyrotron so that the collector dimensions are not related to, and hence restricted by, the wavelength of the output microwaves. The particular preferred coupling includes substantially axial slots in the common wall between the respective waveguides which slots provide selective coupling between the waveguides in the desired modes and limiting mode conversion. The coupling is preferably between a TE.sub.On or TE.sub.ml mode in the outer input waveguide and a TE.sub.On' mode in the inner, output waveguide, n and n' being integers greater than 1. A preferred resonant cavity limits the generated microwaves to a TE.sub.

Abstract: A free electron laser in which the electron beam 12 is sent through the field of a quadrupole magnet 16 which may be untapered or tapered. The beam 12 is sent through the magnet 16 spaced from the symmetry axis of the magnet's poles 22 but on the focusing plane 20 of the quadrupole magnet 16.

Abstract: Method and apparatus for modulating coherent radiation generated by an orotron in accordance with a low voltage control signal applied to the diffraction grating to vary the grating-to-cathode voltage from the cathode-to-collector voltage over a selected voltage range determined by the maximum and minimum values of the control voltage. For amplitude modulation, the grating-to-cathode voltage is varied within a voltage range between a lower voltage at which the orotron output power starts to fall abruptly and a cutoff voltage at which coherent radiation ceases. For frequency modulation, the grating-to-cathode voltage is varied within a voltage range, including the point of maximum power output, where there is a minimum change of output power with a change in the grating-to-cathode voltage.

Abstract: An autogenerating apparatus provides secondary intense relativistic current beam pulses in response to an injected beam pulse. One or more electromagnetic energy storage devices are provided in conjunction with gaps along a beam propagation path for the injected beam pulse. For injected beam pulses which are no longer than double the transit time of electromagnetic waves within the storage devices (which may be resonant cavities), distinct secondary beam pulses are generated by each of the energy storage devices. The beam propagation path, together with the one or more gaps provided therein, operates as a pulse forming transmission line cavity, in which the separate cavities associated with the gaps provide delays for electromagnetic waves generated at the gaps. After doubly traversing the cavity, the electromagnetic waves cause the gap to generate the secondary beam pulses, which are thus delayed by a time interval equal to the double transit time for the induced wave within the cavity.

Abstract: A method and apparatus for increasing the power output and efficiency of an orotron generating near millimeter wavelength radiation. In accordance with a theory of orotron operation described herein and confirmed experimentally, the ribbon-like electron beam utilized in the orotron has a very high current density to effect a large increase in orotron output power and efficiency due to space-charge effects in the beam. In the preferred embodiment, the high density electron beam is generated by a closely-packed rectangular array of field-emission cathodes.

Abstract: An electron beam device which includes a vacuum enclosure which houses an electron gun for producing an annular beam of helically rotating electrons, an iris-loaded waveguide which is supplied with high frequency power and serves to create a high frequency electromagnetic field along the axis of the beam which has a longitudinal electric field component along the beam axis, and a resonator which abstracts high frequency energy from the beam. A coil surrounds the vacuum enclosure to provide a magnetic field of increasing strength with distance downstream in the region of the iris-loaded waveguards whereby the angular velocity of the electrons in the beam is increased with little change in the axial velocity.

Abstract: A technique for accelerating charged particles using an intense traveling electromagnetic wave such as produced by appropriate wavelength lasers. Low energy electrons injected into the focal region of an intense, polarized laser beam are rapidly accelerated in the direction of the beam by the ponderomotive force of the radiation field. The particles reach maximum energy in a distance comparable to the Rayleigh range of a tightly focussed, visible wavelength, diffraction limited pulsed laser. At this point, a combination of induced transverse velocity drifts and/or the rapidly decreasing electric field strengths due to the expanding laser beam envelope cause the particles to enter a low radiation field region before significant deceleration can occur. The resulting device possesses unique advantages and properties not present in existing accelerators.

Abstract: A wide-band distributed coupler for coupling rf energy from an input waveguide into a tapered interaction waveguide in a traveling-wave amplifier comprising a plurality of channel filters connecting between the input and interaction waveguides, with each filter coupled to the interaction waveguide at the appropriate cross-sectional position along its tapered length where the interaction waveguide cutoff frequency approximately matches the wave frequency propagated by the filter. Each filter comprises, in one embodiment, a main coaxial cavity tuned to a distinct center frequency, a first simple isolation cavity for coupling rf energy between the input waveguide and the main cavity, and at least one second simple isolation cavity for coupling energy between the main cavity and the tapered interaction waveguide. This coupler is compatible both in bandwidth and geometry with the tapered interaction waveguide.

Abstract: A tilt-angle electron gun provides a conical beam of electrons for injection into an axially aligned magnetic field of a gyrotron tube. The beam is formed by an electrostatic lens system for focussing and accelerating the electrons within a magnetically shielded region. The conical beam is substantially monoenergetic and laminar so that after injection into the magnetic field the resulting hollow beam has gyrating electrons which have an axial velocity spread sufficiently low for high efficiency gyrotron amplification.

Abstract: A method and apparatus for suppressing lower order cyclotron harmonics in order to permit resonance within a quasi-optical gyrotron/gyroklystron configuration of a desired higher order harmonic. In the gyrotron/gyroklystron configuration at least one open resonator defined by at least two mirrors is positioned downstream from an electron beam source for receiving therethrough the beam of electrons and for exchanging energy therewith. This method includes the steps of choosing a mirror radius size .rho. for the mirrors forming the at least one open resonator which is large enough relative to the spot size of a desired radiation cyclotron harmonic .omega..sub.n so that the harmonic .omega..sub.n oscillates within the at least one resonator, but small enough so that the spot size for the next lower cyclotron harmonic .omega..sub.m is larger than the mirror so that the harmonic .omega..sub.m does not oscillate due to diffraction losses.

Abstract: An RF cyclotron maser type traveling-wave amplifier including an integral active circulator. The amplifier includes a tapered interaction waveguide having a cross-section which gradually increases from a small first end to a larger second end thereof. The waveguide is capable of supporting first and second orthogonal polarization modes therein with approximately the same propagation characteristics for the two modes. A beam of mildly relativistic electrons having helical electron motion is directed into the small first end to axially propagate within the waveguide toward the larger second end. A tapered magnetic field is generated within the waveguide in a direction approximately parallel to the axis of the waveguide. The magnetic field is profiled to near grazing interaction with the second polarization mode of the waveguide. An input electromagnetic wave in the first polarization mode is launched into the larger second end of the waveguide to propagate toward the first end thereof.

Abstract: A complex cavity gyrotron designed for stable operation at high order modes. The device comprises circuitry for generating an annular electron beam, a coupled cavity disposed coaxially with the electron beam and having a first and second adjacent coaxial sections with the dimensions of these coaxial sections adjusted so that different modes with the same azimuthal eigen number but different radial eigen numbers are simultaneously resonant at approximately the same frequency in the two sections, and circuitry for generating an axial magnetic field within the cavity. Few, if any, combinations of modes other than the combination chosen will simultaneously resonate in the cavity thereby effecting higher order mode suppression. The present design has a low susceptibility to beam velocity spread and is effective for any combination of modes with identical azimuthal eigen numbers.

Abstract: A simple method and apparatus are disclosed for producing high power gigat level millimeter radiation from an intensely oscillating relativistic turbulent electron plasma created in and beyond the gap of a high voltage diode configuration. The diode is comprised of an explosive cathode emitter and an extended anode structure connected to the inner and outer conductors, respectively, of a high voltage pulse line under conditions of space charge saturation. The gap spacing and voltage determine the dominate mode of the turbulent longitudinal waves which are directly converted into free transverse waves polarized parallel to the electron beam. A simple coaxial reflector-antenna system is also utilized to direct and focus the resultant radiation.

Abstract: A gyromagnetron amplifier for radiation at millimeter wavelengths comprising a tapered waveguide tube with longitudinally running vanes in the walls of the tube with the number of vanes chosen to coincide with a desired cyclotron harmonic frequency to be amplified. A beam of spiralling mildly relativistic electrons with an energy of 100 keV or less is directed into the small end of the tapered waveguide tube. A tapered axial magnetic field is set up within the waveguide tube with a low value appropriate to the amplification of a cyclotron harmonic frequency. An electromagnetic wave to be amplified is launched into the waveguide tube to co-propagate and be amplified by the spiralling electron beam. This device is characterized by a wide bandwidth, a low operating magnetic field, a relatively low operating beam voltage, with high power, and the capability of continuous wave operation.

Abstract: This invention concerns a microwave generator. For the purpose of maintaining synchronism between the microwave and electrons, at high energy levels (e.g. 0.5 to 1 MeV), the first part of the generator comprises a cylindrical wave guide, the section of which increases in radius along the direction of propagation of the electron beam. Such generators can be used to obtain millimeter and submillimeter waves, with high transverse evergy (e.g. approximately 10 MeV).

Abstract: A diffraction radiation generator in which a ribbon electron beam is directed over a diffraction grating within an open resonator at a selected velocity to generate coherent radiation. After passing through the open resonator, the ribbon beam is directed through aligned slits in two or more conductive elements to a collector. Progressively negative voltages relative to the grating voltage can be applied to the elements and the collector to decelerate the electrons forming the ribbon beam and thus minimize heating of the collector and increase the operating efficiency of the generator. Also, the elements and the collector can be utilized to analyze the ribbon beam.

Abstract: The improved free electron laser device for scanning a spatial field is generally comprised of a drift tube and a rotatable mandrel. The mandrel is concentrically disposed in the tube so as to define an annular space therebetween. A series of canted mirrors of grooved-like configuration are formed about the mandrel in predetermined spaced relationship to each other and at a predetermined angle to a plane transverse of the mandrel. These mirrors function to reflect and phase redistribute various waves of the wave front so as to form a plurality of asymmetric diffraction patterns in the annular space. By reason of the nutating effect of the canted and rotating mirrors, the projected beam conically and continuously scans a region of the spatial field. In order to minimize the effect of skew waves, a series of circumferentially spaced and longitudinally extending rib-like baffles can be affixed to the tube interior between adjoining mirrors.

Abstract: A low inductance magnetic wiggler for use in electron beam type lasers generates a high intensity spatially periodic magnetic field. The wiggler is formed as a plurality of closed conductive loops having their centers spaced along a common axis. Adjacent loops are connected by a conductor extending parallel to the axis, the connecting conductors being positioned alternately on diametrically opposite sides of the loops.

Abstract: An improved method and structure is disclosed for adjusting the magnetic field generated by a group of electromagnet poles spaced along the path of a charged particle beam to compensate for energy losses in the charged particles which comprises providing more than one winding on at least some of the electromagnet poles; connecting one respective winding on each of several consecutive adjacent electromagnet poles to a first power supply, and the other respective winding on the electromagnet pole to a different power supply in staggered order; and independently adjusting one power supply to independently vary the current in one winding on each electromagnet pole in a group whereby the magnetic field strength of each of a group of electromagnet poles may be changed in smaller increments.