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Conference proceedings front matter may contain various advertisements, welcome messages, committee or program information, and other miscellaneous conference information. This may in some cases also include the cover art, table of contents, copyright statements, title-page or half title-pages, blank pages, venue maps or other general information relating to the conference that was part of the original...
At the l3th International Conference on High-Power Particle Beams held June 2000 in Nagaoka, Japan, we presented a paper entitled «Pulsed Power: Sandia's plans for the new millennium». In that presentation we described the status of pulsed power at Sandia and our vision for moving forward in an uncertain budgetary environment. The ensuing four years have proven to be very productive and we have advanced...
The physics and methods of production of picosecond electron beams are described. The main parameters of such beams and their possible application in the production of high-power microwaves, ultrawideband pulsed radiation, and picosecond high-power pulsed X-rays are discussed.
An overview of progress made in the development of intense electron beam diode for deep penetration radiographic applications is given. The Atomic Weapons Establishment (A WE) has a requirement to develop intense (1000 R at 1 m), fast duration (50 ns) Bremsstrahlung X-ray sources from small areas (<2 mm diameter uniformly filled disc equivalent) at high peak energies (> 10 MeV). In order...
Self-magnetic-pinched diode behavior at 1.5–2 MV was diagnosed using a variety of electrical, radiation, and optical diagnostics. Results are compared with LSP code predictions. Good code-experiment agreement is observed for the most part. A practical diagnostic of electron incidence angles is demonstrated. Optical measurements show the importance of the anode plasma in contributing to gap closure...
The charged-particle dynamics in self-magnetically pinched diodes are examined with the particle-in-cell code LSP. It is shown that the self-electric and magnetic fields determine the electron angles of incidence on the target which, in turn, determine the angular distribution of the emitted X-rays. At low voltages and currents, the self-magnetic field is negligible and the electron flow is space-charge...
Traditionally, paraxial diodes for intense, high brightness, X-ray radiography have utilized a gas-filled cell for electron beam focusing. The spot size for beams produced from such diodes is limited by the decay of the plasma return current, which causes the minimum beam spot location to drift upstream from the converter. Recent simulations using the LSP code have suggested that this drift can be...
Gas-filled focusing cells are routinely used to transport high energy density electron beams for use in flash X-ray radiography experiments. A quantitative description of the underlying physics governing their operation on pulsed-power accelerators is presented. This is followed by a discussion of methods to improve the focal intensity on target to create brighter X-ray sources.
The graphite is a well-known material for explosive emission cathodes due to the high stability and practically unlimited resource of emission ability. Such merits are resulted from the fact that during the explosive electron emission (EEE) topography with nanometer microtips develops and it mainly conserves on the graphite after the process. We have shown previously that nanometer scale tips of 10...
The beam forming with necessary parameters is one of the most important problems at electron beams applying in the technologic aims (the material processing) and electromagnetic radiation generation. The essential effect on this process can have the magnetic field of the branching-off systems suchlike a collector or an anode-grid (systems with a virtual cathode). In this paper the results of theoretical...
The operation features and the main physical parameters of different modifications of hollow anode (HA) plasma sources based either on multi-arc, or on magnetron-like, or on ferroelectric plasma source (FPS) ignition are described. It was found that these HA sources produce in the vicinity of the HA output grid a satisfactory unifonn plasma with a density n≈ 5×1012 cm−3. It was found that during the...
The paper summarizes the recent experiments on the injection and transport across applied B-field of an intense, wide cross-section (∼10 cm) H+ plasma (PB) and ion (IB) beam of 60 to 120 eV and 60 to 120 keV energy, respectively, in vacuum and ambient magnetized H+ plasma of temperature Ti∼5 eV and density of 1012−1013 cm−3. With current densities of 10–30 A/cm2, the PB and IB propagated were undeflected...
In previous work [I] it was shown that transportation of intense electron beams in vacuum by applied magnetic field leads to precession of the beam concerning the axis of the transport channel. The beam precession was investigated by different diagnostics (Faraday cups, current probes, X-ray detectors). It was found that frequency, amplitude and onset time of the beam precession strongly depends on...
The stationary states of an electron beam in a homogeneous drift tube have been studied based on the laws of conservation of energy and z-component of the field and particle momentum fluxes. The theoretical conclusions made in this work agree well with experimental findings (Sinus-7) and with results of simulations by the PIC code KARAT.
The concept of ion accelerator, based on space charge slow wave excitation in overlimiting high current relativistic electron beam (REB) subjected to temporal and spatial modulation has been theoretically and experimentally investigated. Analytical theoretical model and 2.5-D electromagnetic code has been elaborated and applied for study of physical phenomena of low frequency modulation of REB current...
Results of theoretical and experimental investigations on generation of the relativistic (∼1 MeV) electron beam with duration up to 10 µS by strongly elongated ribbon diodes are presented for wide band of their transverse size 10÷140 cm and for the beam current 3÷50 kA, respectively.
New understanding of mechanism of the runaway electrons beam generation in gases is presented. It is shown that the Townsend mechanism of the avalanche electron multiplication is valid even for the strong electric fields when the electron ionization friction on gas may be neglected. The non-local criterion for runaway electrons has been proposed. This criterion leads to the universal two-valued voltage...
The collective oscillations of the charge streams occur at gap with the E×B-field (crossed electric and magnetic fields) by means of the exchanges by momentum and energy between the electrons (ions) and the E×B-field. The crossed field contains the energy density (εE2/2) and the momentum density (εE×B). The auto-excitation and self-organization of the streams occur due to secondary emission of the...
Electron beam is generated by cylindrical multipoint explosive emission cathode 28 cm in diameter and 35 cm in length. The source was made according to triode scheme. Electron kinetic energy is 120 keV, beam current 2 kA, pulse duration 30 µs. The source is applied for modification of the outer surface of fuel cladding elements. Temporal and spatial characteristics of an electron flow are presented.
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