Submillisecond Electron Beam Research Articles

TREATMENT OF SILUMIN SURFACE BY A MODULATED SUBMILLISECOND ELECTRON BEAM

TREATMENT OF SILUMIN SURFACE BY A MODULATED SUBMILLISECOND ELECTRON BEAM

Controlling the Specimen Surface Temperature During Irradiation With a Submillisecond Electron Beam Produced by a Plasma-Cathode Electron Source

In this article, the experimental and theoretical data are presented which demonstrate the possibility of controlling the specimen surface temperature during irradiation with a submillisecond electron beam produced by a plasma-cathode electron source. The specimen surface temperature is controlled by modulating the beam current via appropriate short-time variations in the emission plasma parameters. The temperature ripple factor, measuring less than 5% in our experiments, is defined as the product of the specimen surface temperature and the discretization degree of the beam current and its pulse duration. The efficiency of the method of temperature control is confirmed by numerical simulations. The proposed method opens the way to new applications of plasma-cathode electron sources in science and technology.

The deflection of a wide electron beam from the longitudinal axis of the source with a plasma cathode and plasma anode

An electron source with a plasma cathode based on a low-pressure arc discharge having a grid (layer) stabilization of the emission (cathode) plasma boundary and the open edge of the anode plasma has been used to study the deflection of a broad intense submillisecond electron beam from the electron source axis by a leading magnetic field. Measurements of the energy density distribution of the generated electron beam were made both under conditions of its deflection and in the mode of “direct” transport, when the collector target is in direct line of sight from the emission electrode. It was experimentally shown that the stability of the electron source operation with a beam deflection significantly increases. It allows to expand the range of beam parameters, which opens up new possibilities for use the electron source for both scientific and technological purposes.

Structure and Properties of Electro-Explosive TiC–Ni–Mo Coatings of Die Steel after Electron-Beam Treatment

In this paper, we studied the phase and elemental composition of the surface layer of die steel 5KhNM subjected to electro-explosive sputtering deposited composite TiC–Ni–Mo coating and subsequent pulsed irradiation with a high-intensity submillisecond electron beam. The modes of electron-beam processing providing the formation of a dense, with a mirror gloss, surface layer with a submicrocrystalline structure based on titanium carbide and intermetallic compounds based on Mo, Ni, and Ti are determined. The electron-beam processing of an electro-explosive coating in the melting mode is shown to lead to the formation of a structurally uniform and concentration-uniform surface layer. TiC–Ni–Mo coatings have a 1.26 times higher wear resistance compared to die steel 5KhNM used as a substrate. The microhardness of the formed coatings is 450–2400 HV, the nanohardness is 25.5 GPa, and the modulus of elasticity is E = 398 GPa.

Formation and Transportation of an Intense Sub-Millisecond Electron Beam in a Longitudinal Magnetic Field in the Source with a Mesh Plasma Cathode

The limiting parameters of an intense sub-millisecond electron beam generated in the source with a plasma cathode on the basis of a low-pressure multi-arc discharge with mesh stabilization of the cathode (emission) plasma boundary and mobile anode (beam) plasma boundary are investigated. It is demonstrated that the limiting parameters of the electron beam in the examined electrode system are limited by its energy content on a level of about 4 kJ the excess of which leads to an electric breakdown of the accelerating gap. The optimal pressures are determined at which the beam during its transportation in the longitudinal magnetic field with a preset configuration has maximal parameters for the given electrode system. Different mechanisms of electric breakdown initiation and methods for increasing the electric strength of the high-voltage accelerating gap in this electrode system are discussed.

Generation and transport of submillisecond intense electron beams in plasma cathode vacuum diodes

The paper reports on a comparative study of two different types of diode system for producing intense submillisecond electron beam in a source with low-pressure arc plasma emitter. The first is a planar multi-aperture diode comprising cathode and anode performed as molybdenum grids with 241 round openings of few millimeters in diameter. In the second system electrons are accelerated in a sheath between the grid-stabilized cathode plasma and the open boundary of beam-generated anode plasma. It was demonstrated in experiments that latter system should be advantageous in terms of maximally achievable beam current and total beam energy content, but there are drawbacks connected with slow anode plasma build-up that require further study.

Generation of a submillisecond electron beam with a high-density current in a plasma-emitter diode under the conditions of open plasma boundary emission

The generation of a 250-μs-wide electron beam in a plasma-emitter diode is studied experimentally. A plasma was produced by a pulsed arc discharge in hydrogen. The electron beam is extracted from a circular emission hole 3.8 mm in diameter under open plasma boundary conditions. The beam accelerated in the diode gap enters into a drift space in the absence of an external magnetic field through a hole 4.1 mm in diameter made in the anode. The influence of electron current deposition at the edge of the anode hole on the beam’s maximum attainable current, above which the diode gap breaks down, is studied for different accelerating voltages and diode gaps. The role of processes occurring on the surface of the electrodes is shown. For an accelerating voltage of 32 kV, a mean emission current density of 130 A/cm2 is achieved. The respective mean strength of the electric field in the acceleration gap is 140 kV/cm. Using the POISSON-2 software package, the numerical simulation of the diode performance is carried out and the shape of steady plasma emission boundaries in the cathode and anode holes is calculated. The influence of the density of the ion current from the anode plasma surface on the maximum attainable current of the electron beam is demonstrated.

Novel Injector of Intense Long Pulse Electron Beam for Linear Plasma Devices

A novel high-power (10 MW) sub-millisecond electron beam is developed for injection into the open (linear) plasma devices. The beam is produced by extraction of electrons from a plasma of pulsed arc discharge in hydrogen. The beam is extracted and accelerated with multiaperture diode-type electron optical system with 241 small round apertures, which are arranged in a hexagon-al pattern. The injector prototype was installed into the end plasma tank of GOL-3 multiple mirror trap and tested to produce an electron beam with up to 100 keV electron energy, about 100 A total beam current and 0.7 ms or longer pulse duration. In a series of preliminary experiments the electron beam was injected into the GOL-3 plasma chamber filled with deuterium gas with a density of 1014-1015cm-3 and transported in a corrugated magnetic field (<B> up to 1.4 T) along the trap at a distance of 12 m.