[en] Presented here are design criteria for a full scale (70 cm) WIP electron gun system capable of long run operation with the following specifications: foil area approx. 70 x 1 cm, electron beam current density approx. 1 A/cm², pulse length < 200 ns FWHM, pulse tail < 25f f pulse energy, average current approx. 2 ma/cm², voltage -150 kV, voltage droop < 10%, Rep rate approx. 10 KHz, power approx. 20 kW, run time approx. 30 min, and jitter approx. 10 μs

[en] This Proposal is an updated version of FWP submitted in March 1992. Significant work has been done since the original proposal, and much of this is reported on in this update. In addition there have been several changes made, some in response to suggestions made by the three reviews sent to us in December, 1992. The new information and changes include: Technical information on the proposed design of the magnetron gun, the magnet, acceleration gap, and electrical system (including a comment on efficiency loss due to high-voltage leakage current). Modification of the phase I and II tests to allow operation of the gun and klystron off the axis of the magnet, thus simulating the magnet situation when multiple beams are used. Modification of phases III and IV to test a cluster of three beams: first a three beam gun, and then three beams with a klystron on one of them. We have added a phase V which would be the testing of a full three-beam demonstration klystron. The mod-anode pulser would now be located on the high voltage deck instead of externally. Power for the pulser and other high voltage components would now be provided by an isolation transformer instead of from a lead battery. We believe these changes have improved the proposed program and thank the reviewers for their constructive suggestions. The design is still evolving. Relatively little work has been done on the detailed klystron design, and none on the beam dump

[en] This invention relates to a pulsed electron gun comprising a leak-tight insulating tube closed at one end. A voltage of several tens of kilovolts is applied by cables to the ends of the tube. Among its other features this gun includes a conducting tube fitted inside an insulating tube on the same centre line, in a leak-tight manner to it. This conducting tube forms the grid support, and the bottom of the well so formed being closed by a conducting plate insulated from the conducting tube by an insulating ring, this plate becomes the support of the gun cathode. The grid support is part of the vacuum containment so formed. The electron linear accelerator comprising such a pulsed electron gun is also described

[en] Using a plane-frustum of conus cathode geometry, a cold cathode glow discharge electron gun is obtained. The electron beam originates in the plane surface of the cathode, while the plasma originates in the inner surface of the frustum of conus. The optimum pressure of operating was found to be around 0.1 mm.Hg. (author)

[en] A ring-shaped electrode with numerous functions has been tested: it provides angular confinement of the electron emission and protects the tip against breakdown; the lifetime of the tip may reach a thousand hours. The qualities of the field-emitted beam are preserved as is shown by the results obtained when a transmission electron microscope was equipped with this device. In spite of their remarkable properties such as high brightness and low energy spread, field-emission sources of electrons have had rather poor commercial success up to now. This can be understood because of the technological problems associated with their use and particularly, with the vacuum requirements. In practice it seems that the real difficulties are to achieve a sufficiently stable and high beam current and to obtain a reasonable cathode lifetime. The technique presented here does not solve all the problems but it is a new approach to a part of the solution. (orig.)

[en] In the high-voltage power supply system of the electron beam evaporator steep current rises and drops in the case of short circuits are avoided. For this purpose a pulse protection filter is installed in the circuit leading to the cathode. It consists of a capacitor connected parallel to the junction cathode/anode, a choke, a free-running diode blocked in the direction to the cathode, and a discharge resistor. (DG)

[en] The invention is an apparatus for producing a beam of electrical particles including a housing containing a gas at low pressure, two separated electrodes, and a grid transparent to the particles between the two electrodes. The grid is located nearer one electrode. The pressure-distance product of the grid with the two electrodes lies below the negative slope region of the Paschen curve. Means is provided for applying a first voltage of one polarity between the first electrode and the grid, not sufficient to produce a self-supporting discharge between the electrode and grid; and means is also provided for applying a second voltage, of the same polarity but lower than the first voltage, between the grid and the second electrode to produce a self-supporting discharge. (LL)

[en] This paper describes the development of an electron gun for a sheet beam klystron. Initially intended for accelerator applications, the gun can operate at a higher perveance than one with a cylindrically symmetric beam. Results of 2D and 3D simulations are discussed

[en] Tests of the Boeing Average Power Laser Experiment (APLE) injector have demonstrated first-time operation of a photocathode RF gun electron accelerator at 25% duty factor. The multi-alkali photocathode was illuminated by a frequency-doubled, mode-locked ND:YLF laser. The cathode was placed in the first cell of four single-cell cavities resonant at 433 MHz. The 4 cavities accelerated the beam to 5 MeV. The pulse duration was 8.3 ms and the repetition rate was 30 Hz. True average beam currents of up to 35 mA have been accelerated to 5 MeV for an average beam power of 170 kilowatts. The 35 mA beam current exceeded previous photocathode performance by a factor of 1000

[en] Charge lifetime of strained superlattice Gallium Arsenide photocathodes in dc guns is limited by ion back bombardment. In this work, we propose and present simulation results for an offset anode scheme to increase charge lifetime in dc guns. In this scheme, the axial symmetry of the cathode-anode configuration is broken by offsetting the anode transversely, while keeping the laser spot on the electrostatic center. This eliminates the bombardment of high energy ions on the cathode and enables maximum usage of the available cathode area. Depending on the size of the available cathode area, this method can increase the charge lifetime by an order of magnitude compared to the current best alternative method. An anode assembly, capable of in-vacuum movement, is required for this method, which has been designed and fabricated at Brookhaven National Laboratory. Authors: