Abstract: A variable spot size x-ray tube comprises a cathode having an electron emitting surface providing an electron beam that travels essentially along the tube axis of symmetry to an anode. The anode, spaced from the cathode, includes a target, the front surface of which is disposed at an oblique angle with respect to the axis of symmetry. The potential of the anode is generally positive with respect to that of the cathode. The cathode is heated to a temperature at which electrons are emitted by the thermionic emission process. Current from the cathode can be controlled by varying the cathode temperature if the cathode is operated in the temperature limited region. The incident electron beam forms a spot on the target surface whereupon x-rays are produced in response to impingement of the electron beam on the target. The x-rays propagate outwardly from the target spot through a vacuum window to form a beam of x-radiation outside the x-ray tube.

Abstract: An electron gun for use in remediation of hazardous volatile organic compounds is provided. The electron gun comprises a cathode having a concave emitting surface and a dome-shaped focusing electrode concentrically surrounding the emitting surface. The focusing electrode has an inwardly protruding lip portion that extends at least partially into a beam focusing region defined in front of the emitting surface. A target grid is spaced from the cathode and a negative voltage is applied between the emitting surface and the target. The target grid has a surface area that is substantially larger than an associated surface area of the emitting surface. An electron beam is provided by the emitting surface in response to the negative voltage, and is focused into a broad diverging beam by the focusing electrode. The electron gun may be configured for temperature limited emission or space charge limited emission.

Abstract: A flood beam electron gun is provided for use in remediation of hazardous volatile organic compounds (VOC) contained within a detoxification vessel. The flood beam electron gun comprises an electron emitter having a rounded emitting surface providing a conical electron beam. A control grid is spaced from and disposed substantially parallel to the emitting surface. The control grid has a plurality of holes disposed in a first pattern providing an array of individual electron beams from the conical electron beam of the emitter. An intermediate electrode is spaced from the emitter and the control grid, and has an aperture therethrough providing a substantially parallel flow of the array of individual electron beams. A target grid is spaced from the intermediate electrode and opposite from the cathode and control grid. The target grid has a plurality of holes disposed in a second pattern that is proportional to and substantially larger than the first pattern.

Abstract: An advanced center post (ACP) gun is provided which is capable of producing either a large orbit or small orbit electron beam. The gun comprises an annular shaped cathode, a control electrode adjacent the cathode, and an annular anode having an opening therethrough. A center post is disposed axially within the center region of the cathode and the control electrode along a center line of the electron gun and interaction region of a microwave device. The anode is shaped in conjunction with the center post to control position of equipotential lines of an electric field provided in an inter-electrode space between the cathode and the anode so that an electron beam emitted by the cathode converges at the anode opening. The control electrode provides electrostatic focusing of the beam to further control the beam convergence. Multiple polepieces provide accurate control of the magnetic field in the interaction region to shape the beam and control the orbit size and velocity spread.

Abstract: An electron collector is provided for collecting spent electrons generated by a cathode of an electron gun after passage through an interaction region of a microwave device. The collector comprises a bucket having internal walls which define an enclosed region having an entrance aperture through which electrons pass after exiting the microwave device. An electrode is disposed proximate the entrance aperture within the enclosed region. A positive potential is applied to the electrode with respect to the microwave device. The potential forms a substantially ion-free region at the entrance aperture which promotes the efficient dispersal of the spent electrons due to space charge.

Abstract: An electron beam focusing system is provided within a microwave amplification tube formed from a plurality of magnetic polepieces interposed by non-magnetic spacers. The tube has an axially disposed beam tunnel which permits projection of the electron beam therethrough. A magnetic field is induced in the tube having lines of flux which flow through the polepieces along a magnetic axis. Heat formed within the circuit flows through the spacers to an external planar surface along a thermal axis, which is non-coincident with said magnetic axis. In an alternative embodiment, a plurality of the tubes can be combined into a common system for focusing a plurality of electron beams. The tubes within the common system share heat sinks which attach to the planar surfaces.

Abstract: A Pierce electron gun is provided having a cathode, a focusing electrode surrounding the cathode, and an anode disposed a fixed distance from the cathode and having an opening therethrough. The electron gun has at least one grading electrode disposed between the focusing electrode and the anode. The grading electrode controls shape of equipotential lines of an electric potential difference provided between the anode and the cathode, to purposely reduce field gradient levels formed by the electric potential difference. The grading electrode further has a double radial bend having an inner radial curve of a first radius and an outer radial curve of a second radius.

Abstract: A high-power switch tube is shown constructed from a plurality of electron guns each gun having a cathode and an anode. Between the cathode and anode is mounted a shadow grid closest to the cathode beyond which is mounted a control grid, a screen grid, and, in some applications, by a suppressor grid. Each anode is formed with an anode cavity having an opening that is smaller in dimension than the largest dimension of the cavity thus forming a Faraday cage collector which prevents secondary emission problems.

Abstract: An improved grid arrangement is shown for a gridded electron gun wherein the control grid and/or shadow grid is provided with tapering grid vanes which reduce the amount of voltage required to cut off the electron beam. Alternately, a fewer number of grid vanes may be utilized to accomplish the same cutoff of the electron beam thus reducing the loading on the cathode and improving the transmission of the electron beam.

Abstract: An improved dual-mode electron gun includes a close-in and a further control grid to control the laminar flow of electrons which pass from the smooth spherical surface of a cathode toward an annular anode. In the high mode of operation, the close-in grid is maintained, for example, at +36 volts while the further grid is maintained at +250 volts. During the low mode of operation, the close-in grid is maintained at -36 volts while the further grid potential is +250 volts. The two control grids are divided into inner circular and an outer annular areas. The close-in grid has more conductive elements in its outer annular area than in the same area of the further grid. The two grids are then aligned so that the close-in grid functions as a control grid to block the flow of electrons from the outer annular area during the low mode of operation and as a shadow grid for the further control grid during both low and high modes of operation.

Abstract: A high power pulsed electron beam is produced in a system comprised of an electron gun having a heated cathode, control grid, focus ring, and a curved drift tube. The drift tube is maintained at a high positive voltage with respect to the cathode to accelerate electrons passing through the focus ring and to thereby eliminate space charge. A coil surrounding the curved drift tube provides a magnetic field which maintains the electron beam focused about the axis of the tube and imparts motion on electrons in a spiral path for shallow penetration of the electrons into a target. The curvature of the tube is selected so there is no line of sight between the cathode and a target holder positioned within a second drift tube spaced coaxially from the curved tube. The second tube and the target holder are maintained at a reference voltage that decelerates the electrons.

Abstract: An electronic countermeasures system for use at an operating frequency, f, includes a receiving antenna, a transmitting antenna, and first and second turnstile junctions, in which each of the junctions comprises the geometry of four rectangular ridged waveguides arranged as arms in the shape of a cross, and a fifth cylindrical quadridge waveguide opening into the common intersection of said arms and extending orthogonal to such formed cross and with each of two opposed ones of the waveguide arms including a short circuit termination, the effective distance between such short circuit terminations being equal to one-half wavelength at the operating frequency.