Abstract: Some electrons reflected from the collector of a klystron form a beam current flowing back toward the input end of the tube. This beam is modulated and can carry a regenerate signal which distorts the tube's performance when amplifying a television signal. The reflected electrons are removed by a spiralling transverse magnetic field having a pitch equal to the cyclotron wavelength in the axial magnetic field used to focus the beam. The rotative sense of the spiral is such that forward-going beam electrons are not affected but returning electrons are accelerated in their cyclotron orbits until they are driven outside the beam and are collected.

Abstract: A power amplifier including a klystron is stabilized against variations in output power with a simplified servo-loop system and cooperating temperature compensation. The system is fully solid-state, digital, and includes an operator-presettable initial power selector, a power output sensor, comparator logic, variable attenuation responsive to error signals indicative of deviation from the preset power, and temperature compensation means, for assured accuracy and stability.

Abstract: An efficient relatively high-power inductive output linear electron beam tube with broad-band capabilities is disclosed which is density modulated with a grid applying to the beam an RF modulating signal. The grid has a large active area which may be of the order of ten square inches, is closely spaced one-twentieth the grid diameter or less to a thermionic cathode, and is comprised of a plurality of curved thin narrow elongated members. With the aid of an annular anode downstream of the grid, the beam is accelerated by DC potential of at least several kilovolts. A high-isolation input signal means includes adjacent but physically and electrically isolated wide-diameter, axially reduced annular cathode and grid lead means for leading both the DC beam-accelerating potential into the cathode, and the modulating RF signal into the grid with minimal impedance.

Abstract: In a microwave electron tube such as a gyrotron, a hollow beam of electrons passes thru the interaction cavity into an output waveguide carrying the generated energy in a mode with circular electric fields. According to the invention, the beam is caused to expand, passing thru a gap in the waveguide to be collected on a larger, surrounding collector. The collector energy is thus reduced. The wave energy jumps the gap and continues down the waveguide. Wave energy leaking into the collector may be absorbed by lossy material therein or be carried off by waveguides to external loads.

Abstract: A solenoidal magnet coil is used to generate an axial field for focusing a beam of electrons through a linear-beam electron tube. In high-power tubes, the coil typically cannot extend over the entire length of the focused electron beam because it would interfere with the waveguide used to carry out the generated wave power. Thus the axial magnetic field strength falls off near the output end, a region in which it would be desirable to have it uniform or even slightly increasing. Very often the coil is foil-wound and its output end has a notch to allow passage of the waveguide. A similar notch 180 degrees away compensates the sideways distortion of field caused by displacement of coil current away from the notch impediment. In the non-notched regions the current spreads throughout the coil cross-section, but there is still a fall-off of field strength on the axis due to current displacement away from the output end.

Abstract: A slow-wave circuit suitable for a high-frequency traveling-wave tube has an array of metallic ladder rungs extending transversely across an elongated envelope and not in contact with the envelope except at the ends of the rungs. The envelope has a cross-shaped section to provide a fundamental backward wave. The rungs preferably have aligned apertures to pass a beam of electrons in traveling-wave interaction with the circuit.By making the rungs transversely broader than a critical value, the lowest passband of the circuit has poles of impedance at both its ends, whereby more efficient interaction is obtained, along with greater stability.

Abstract: This invention concerns a slow-wave circuit which is electrically equivalent to the well-known folded-waveguide or coupled-cavity circuit with staggered coupling slots. The central portion of the circuit is a metallic ladder. The ladder rungs are wide and flat to form the equivalent of flat cavities. The rungs have axially aligned holes thru their centers for beam passage. A pair of coupling ladders are joined to opposite sides of the central ladder. They have apertures or recesses spaced at twice the pitch of the central ladder; the recesses are aligned to provide a coupling duct between each pair of adjacent cavities, and cavity-closing walls at the ends of the pair. The coupling recesses in the two coupling ladders are staggered by the cavity pitch so that the coupling ducts are on alternating sides of the cavities.

Abstract: In a Gyrotron electron tube, oscillating motion perpendicular to the axis of a linear electron beam is produced by a helical component of magnetic field. The length along the beam of the helical field is critically chosen so that electrons at various radii from the axis all acquire equal transverse energy.

Abstract: High-power linear-beam electron tubes require an extended uniform magnetic field to focus their beam in an elongated cylinder. When permanent magnets are used to energize the magnet structure, there is inevitably a leakage field outside the main flux-return path. The leakage field can refocus the beam in the tube's collector, damaging it. When the collector has air-cooling fins, it is not practical to shield it completely with magnetic material. In the invention, the leakage field is reduced by making the energizing magnet at the collector end axially magnetized and the magnet at the cathode end radially magnetized. Also, a shield around the outside of the fins may be added.

Abstract: A simplified, compact, flat microwave frequency converter assembly utilizes a flat quad diode bridge, and has two pairs of opposed flat conductors, each with a respective one of the opposed conductors on a respective side of a flat dielectric substrate . Each of the pair extends orthogonally from their intersection at the bridge. The bridge is connected at opposite corners thereof to adjacent ends of the conductors at the intersection on a first side of the substrate. These first-side conductors are in electrical continuity with a conductive layer extending about the periphery of the substrate on the first side thereof. This layer is, in turn, in contact with a conductive carrier plate by means of which the layer is grounded. On the second side of the substrate, each of the pair of capacitors affixed to the substrate is connected between respective opposite corners of the bridge, and the adjacent ends of the conductors of one of said pairs.

Abstract: A window assembly for a hollow waveguide of circular cross-section, with improved bandwidth and cooling capability for handling high microwave power transmissions over wide frequency ranges, is disclosed. A plate or disc of dielectric of refractive index n.sub.1 extends sealingly across the waveguide and has two parallel faces which exhibit a pattern of corrugations. One of these faces is in contact with a dielectric fluid of refractive index n.sub.2, and means are provided for cooling and circulating the fluid over said one face. Each of the corrugations extends into the fluid a distance proportional to the inverse of the geometric mean of the product of the refractive indices n.sub.1, n.sub.2. In a preferred embodiment, a second plate is included, separated from the first by a region in which said dielectric fluid is circulated, and in which at least both the faces in contact with the fluid are corrugated.

Abstract: A window assembly for ridged waveguide has a slab of dielectric extending clear across the waveguide cross-section. The slab may be perpendicular to the waveguide or cross it at an angle. The waveguide ridge or ridges are notched so that the dielectric slab passes through the notch. Inductive tuning posts may be added to make a broadband match. The window assembly has an excellent match over more than an octave frequency range.

Abstract: Relatively wide workpieces, such as auto grilles, are rapidly conveyed into and from a vacuum processing chamber provided with entry and exit air locks and vacuum isolation valves, in which thin metallic coatings are deposited uniformly over workpiece surfaces. The gate member of the valve is supported for sliding vertical movement, as well as limited outward and inward movement for sealing the chamber opening, at the protruding ends of an elongated member backing the gate. Air cylinders act directly on these ends to close the gate. A linkage and air cylinder above the gate vertically propels the gate. The processing chamber is provided with several side by side arrays of sputtering sources with circular cathodes, the workpieces moving thereunder at a steady rate orthogonally to the arrays.

Abstract: A system for the automated handling and transfer of wafers individually and repetitively to and between processing stations and cassettes. A track-like conveyor engages a cassette holding a plurality of wafers in vertically facing alignment, to move same horizontally past a loading station of a processing chamber. A vertically moveable blade passes between the conveyor tracks and through the cassette to engage a wafer edgewise from below and move same upwardly to the processing chamber entrance. Vacuum means mounted to the door of the chamber entrance engages and holds the wafer during insertion into the chamber by closure of the door. Clip means are mounted within the periphery of an aperture of a vertical support plate just within the chamber entrance, to engage edgewise the wafer and support it within the plate aperture while in the processing chamber. The wafer is removed after processing by operating the foregoing apparatus in reverse order.

Abstract: A dispenser cathode is fabricated by covering a reservoir of electron emitting material with a perforated metal foil having an appropriate pattern of pore-sized apertures thereon for providing uniform electron emission from the cathode surface. The electron emitting material is in the form of a pellet of barium oxide impregnated with a wax or resinous material to minimize chemical reduction of the barium oxide in air. The impregnated barium oxide pellet is sandwiched between the apertured foil and a support structure to which the foil is welded. During tube bake-out or subsequently during cathode activation, the wax or resinous material evaporates and barium oxide migrates through the apertures to cover the surface of the foil in a uniform manner. The desired pattern of apertures in the foil is achieved by photolithography, or by forming the foil (e.g., by chemical vapor deposition, sputter deposition, evaporation, or sintering) on a substrate containing an array of protruding posts.

Abstract: An assembly is provided for protectively supporting semiconductor wafers individually within a support while permitting processing of both faces of the wafer, as well as facilitating rapid insertion and removal of wafers into the support, and movement of wafers between processing stations. The assembly includes a plate-like support through which is defined an aperture of diameter larger than the wafer, and a plurality of clips mounted within the periphery of the aperture and the plane thereof and resiliently gripping edgewise a wafer inserted into the aperture and supporting same within the plane of the aperture. Each clip extends centrally inwardly of the aperture and terminates in an arcuate portion within which the edge of the wafer is retained, and defines a flat portion generally parallel to the aperture plane.

Abstract: In a traveling wave tube (TWT) with a non-dispersive interaction circuit such as a helix, the length of the circuit in wavelengths, and hence the gain of the tube, varies with the frequency. The variations of gain over a very wide bandwidth can cause oscillation problems. The invention provides an inverse variation with frequency of the physical length over which the circuit interacts with the beam. This is done by resonant attenuators coupling to the interaction circuit over various lengths depending on their resonant frequency, the attenuation being enough to effectively remove the interaction circuit wave. The attenuators are preferably formed of resonant sections of slow-wave circuit deposited on longitudinal ceramic rods such as the helix support rods.

Abstract: In traveling wave tubes with broad bandwidth, such as an octave or more, the gain varies by many dB across the band. One or more lossy circuits inside the tube coupled to the interaction helix-type slow-wave circuit are resonant at frequencies within the operating band. They provide a loss varying with frequency to compensate for the gain variation. The resonant circuits are typically metallized patterns on a dielectric rod which may be a support rod for the interaction circuit. Compared to an external gain equilizer in the drive circuit of the TWT, the internal equalizer is cheaper and provides a better noise figure.

Abstract: A real-time ultrasonic imaging system is disclosed which includes an array of transducers adapted for propagating ultrasonic energy into a body to be ultrasonically examined and for receiving reradiated energy from points within the body. A plurality of signal channels each includes a transmitter branch and a receiver branch associated with respective transmit and receive transducers, or both branches may share a single transducer. A transmitter branch activates a transducer to propagate the sonic energy and a receiver branch receives from the transducer electrical signals corresponding to the reradiated energy. Memory means in each receiver branch receive and store data indicative of the signal level passed to the channel by its associated transducer. Display means are provided for receiving the data from the memory means in each of the channels and for combining and processing such data to effect a real-time display of the bodily portion being examined.

Abstract: Disclosed is an apparatus for simultaneously winding multiple strands of wire into turns about a toroidal core in rapid fashion. The apparatus includes a U-shaped wire receiving channel having a semi-circular portion with a gap and a pair of open-ended legs. The ends of the channel legs are positioned adjacent opposite sides of a rotatably mounted drum which is driven by a resilient endless belt engaging approximately one half of its annular outer surface. A toroidal core is supplied and rigidly supported in the gap by a core feeding mechanism. A grooved gap crosser is thereafter extended through the central opening of the core to bridge the gap and complete the channel. A pair of pinch roller type feed/brake mechanisms propel and guide the leading ends of the wires into the channel, through the core opening, and up one channel leg to the drum.