Publications

Which current pulsed accelerator technology was developed during the late 60`s through the late 80`s to satisfy the needs of various military related applications such as effects simulators, particle beam devices, free electron lasers, and as drivers for Inertial Confinement Fusion devices. The emphasis in these devices is to achieve very high peak power levels, with pulse lengths on the order of a few 10`s of nanoseconds, peak currents of up to 10`s of MA, and accelerating potentials of up to 10`s of MV. New which average power systems, incorporating thermal management techniques, are enabling the potential use of high peak power technology in a number of diverse industrial application areas such as materials processing, food processing, stack gas cleanup, and the destruction of organic contaminants. These systems employ semiconductor and saturable magnetic switches to achieve short pulse durations that can then be added to efficiently give MV accelerating, potentials while delivering average power levels of a few 100`s of kilowatts to perhaps many megawatts. The Repetitive High Energy Puled Power project is developing short-pulse, high current accelerator technology capable of generating beams with kJ`s of energy per pulse delivered to areas of 1000 cm{sup 2} or more using ions, electrons, or x-rays. Modular technology is employed to meet the needs of a variety of applications requiring from 100`s of kV to MV`s and from 10`s to 100`s of kA. Modest repetition rates, up to a few 100`s of pulses per second (PPS), allow these machines to deliver average currents on the order of a few 100`s of mA. The design and operation of the second generation 300 kW RHEPP-II machine, now being brought on-line to operate at 2.5 MV, 25 kA, and 100 PPS will be described in detail as one example of the new high average power, high current pulsed accelerator technology.

Short-pulse accelerator technology developed during the early 1960's through the late 1980's is being extended to high average power systems capable of use in industrial and environmental applications. Processes requiring high dose levels and/or high volume throughput will require systems with beam power levels from several hundreds of kilowatts to megawatts. Beam accelerating potentials can range from less than 1 MeV to as much as 10 MeV depending on the type of beam, depth of penetration required, and the density of the product being treated. This paper addresses the present status of a family of high average power systems, with output beam power levels up to 200 kW, now in operation that use saturable core switches to achieve output pulse widths of 50 to 80 nanoseconds. Inductive adders and field emission cathodes are used to generate beams of electrons or x-rays at up to 2.5 MeV over areas of 1000 cm2. Similar high average power technology is being used at ≤ 1 MeV to drive repetitive ion beam sources for treatment of material surfaces over 100's of cm2. © 1995.

A series of test has evaluated the current-carrying characteristics of several proposed detonator strong safety link (DSSL) drive cables to conduct current into an electrically simulated radiation case enclosure. The drive cables tested included a dielectric cable made up of either one or two braided Kevlar threads in a polysulfone sleeve, an existing DSSL conductive drive cable similar to a bicycle shift cable, with and without an external ground-strap diversion feature, and the flex circuit hook assembly used for DSSL instrumentation purposes. Each of the test samples was connected to a 200-kV, 30-kA Marx generator and terminated inside an electrically simulated radiation case enclosure. Two lengths of drive cables (4 and 13 in.) within the simulated radiation case were tested for each type. The results indicate that the conductive drive cables without an external short-circuit diversion feature conducted about 5 to 9 times as much current into the simulated radiation case as either the dielectric drive cables or the conductive drive cables with an external short-circuit feature. Surprisingly, the flex circuit hook assemblies, both the short and long cables, conducted nearly 100% of the available current into the simulated radiation case enclosure. The next series of experiments will repeat the tests at the SNL Lightning Facility in order to scale the results up to the maximum lightning threat levels of 200 kA. 18 figs., 1 tab.