[en] High power, phase coherent pulses are generated by superconducting apparatus which includes a superconducting cavity resonator that is pumped by a low power microwave source while being isolated from a load. Switching of the cavity to an emitting mode is accomplished in 5 to 10 nanoseconds by firing a gas discharge tube that acts to couple the activity to the load while decoupling it from the pumping source

[en] Earlier Microwave Measurements of the ETA Accelerating Cells has uncovered eleven resonances in the frequency range of 0 > 850 MHz. The Q values of these modes ranged from 14 to 70. A three phase program directed at substantially reducing these Q values is reported. In particular the dampening methods described below resulted in a decrease of Q value from 40 to 5 for the beam breakup mode (TM₁₁₀) with a corresponding reduction for most of the other cavity modes

[en] Experiments at the Lawrence Livermore National Laboratory (LLNL), University of California, in conjunction with the University of California at Davis have shown induction linear accelerators (linacs) to be suitable for radiation processing of food. Here we describe how it might be possible to optimize this technology developded for the Department of Defense to serve in radiation processing. The possible advantages of accelerator-produced radiation over the use of radioisotopes include a tailor-made energy spectrum that can provide much deeper penetration and thereby better dose uniformity

[en] Several techniques using small radius collimating pipes with and without axial magnetic fields to measure the brightness of an extracted 1 - 2 kA, 1 - 1.5 MeV electron beam will be described. The output beam of the High Brightness Test Stand as measured by one of these techniques is in excess of 2 x 10⁵ amp/cm²/steradian. 5 refs., 4 figs

[en] This patent describes an apparatus capable of acceleration of electrons to energies of at least 1 MeV at currents of at least 100 A over a time interval of at most 1 μsec. and pulse repetition rates of up to 20 kilohertz, the apparatus comprising: an electron beam injector for generating focused beam of electrons of energy substantially ≥0.1 MeV; substantially identical accelerator modules, each module serving to receive the beam of electrons and to increase their kinetic energies by substantially 0.1-1.0 MeV, each module having a module axis that is coaxial with the axis of the electron beam injector, each accelerator module comprising: a toroid of ferromagnetic material, with the axis of the toroid being coaxial with the electron beam injector axis and with the inner diameter of the toroid being sufficient to allow the electron beam produced by the electron beam injector to pass through the hollow center of the toroid along the toroid axis; and a hollow cylindrical electrical conductor, with cylinder axis coaxial with the toroid axis, adjacent to the toroid and making at least one complete turn around the toroid generator, for thereby transporting a voltage pulse about the toroid and abruptly changing the magnetic induction of the toroid ferromagnetic material

[en] A pulse-forming network for generating an initial voltage pulse of duration substantially one microsecond or greater and for reforming the pulse as a voltage pulse with a time duration of no more than 100 nanoseconds and pulse rise time and pulse fall time of at most 20 nanoseconds each and delivering the pulse to a predetermined electrical load is described comprising: a voltage pulse source having an output terminal and capable of producing a sequence of one or more output pulses of current at least 20 kamps, voltage at least 20 kV and pulse duration substantially one μsec or greater; a first capacitor having two terminals, with one terminal thereof being grounded and with a second terminal being operatively associated with the output terminal of the voltage pulse source; a first saturable inductor having two terminals and with inductances satisfying L/sup (unsat)/L/sup (sat)/≥100, with a first terminal thereof operatively associated with the second terminal of the first capacitor; a pulse transmission line having an associated impedance of substantially two ohms, with a first terminal thereof operatively associated with a second terminal of the first saturable inductor; a second saturable inductor having two terminals and with inductances satisfying L/sup (unsat)/L/sup (sat)/≥100, with a first terminal thereof operatively associated with a second terminal of the pulse transmission line and with a second terminal thereof electrically connected to a load; and a grounded, electrically conducting tube substantially surrounding the electrical connection between the second saturable inductor and the load

[en] The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability

[en] The principal undertaking of the Beam Research Program over the past decade has been the investigation of propagating intense self-focused beams. Recently, the major activity of the program has shifted toward the investigation of converting high quality electron beams directly to laser radiation. During the early years of the program, accelerator development was directed toward the generation of very high current (>10 kA), high energy beams (>50 MeV). In its new mission, the program has shifted the emphasis toward the production of lower current beams (>3 kA) with high brightness (>10⁶ A/(rad-cm)²) at very high average power levels. In efforts to produce these intense beams, the state of the art of linear induction accelerators (LIA) has been advanced to the point of satisfying not only the current requirements but also future national needs

[en] The use of magnetic switches to generate high power pulses has opened up a whole new spectrum of possibilities. Here we describe an investigation into the maximum repetition rates possible with these devices

[en] Low-pressure switches and magnetic switches have been tested as possible replacements for the high-pressure switches currently used on Experimental Test Accelerator (ETA) and Advanced Test Accelerator (ATA). When the low-pressure switch is used with a low-impedance transmission line, runaway electrons form a pinched-electron beam which damages the anode. We have tested the use of the low-pressure switch as the first switch in the pulsed-power chain; i.e., the switch would be used to connect a charged capacitor across the primary winding of a step-up transformer. An inductor with a saturating core is connected in series so that, initially, there is a large inductive voltage drop. As a result, there is a small voltage across the switch. By the time the inductor core saturates, the switch has developed sufficient ionization so that the switch voltage remains small, even with peak current, and an electron beam is not produced. A 15 μF capacitor was used with charge voltages up to 50 kV. The time-to-current maximum was 5 to 8 μs. The current terminated at about 50 μs, and the voltage could be reapplied at about 100 μs