Ion velocities in vacuum arc plasmas have been measured for most conducting elements of the Periodic Table. The method is based on drift time measurements via delay between current modulation and ion flux modulation. A correlation has found element-specific velocity average charge state; however, differently charged ions same element approximately velocity. These findings contradict potential hump model but are agreement with a gasdynamic that describes acceleration as driven by pressure...

We have investigated the charge state distributions of metal ions produced in a high current vacuum arc plasma located strong magnetic field. The was varied over range 200 A to 4 kA and field from zero up 10 kG. In general, effect both is push distribution higher states-the mean ion increased new states are formed. These effects explained terms power input (higher temperature) delayed freezing during expansion process.

Abstract This paper presents a review of physical principles, design, and performances plasma-cathode direct current (dc) electron beam guns operated in so called fore-vacuum pressure (1–15 Pa). That operation range was not reached before for any kind sources. A number unique parameters the e-beam were obtained, such as energy (up to 25 kV), dc 0.5 A), total power 7 kW). For generation at these relatively high pressures, following special features are important: probability electrical...

Vacuum arc ion sources have been made and used by a large number of research groups around the world over past twenty years. The first generation vacuum (dubbed “Mevva,” for metal vapor arc) was developed at Lawrence Berkeley National Laboratory in 1980s. This paper considers design, performance parameters, some applications new modified version this kind source which we called Mevva-V.Ru. produces broad beams ions an extraction voltage up to 60 kV time-averaged beam current milliampere...

We report on measurements of the charge state distributions ions formed in a vacuum arc plasma magnetic field. A ion source was used for formation and beam extraction, spectra were investigated using both time-of-flight diagnostics. find that states all metal species are significantly increased by field up to 6 kG. New high created, mean distribution is about 30% at 3.75 kG 50% The results important fundamentally as well being relevance applications such implantation accelerator injection.

The ion current from different cathode materials was measured for 50-500 A of arc current. normalized by the found to depend on material, with values in range 5% 19%. generally greater elements low cohesive energy. erosion rates were determined and charge states, which previously same source. absolute ranged 16-173 /spl mu/g/C.

In the irradiation of an insulated target by electron beam produced a plasma-cathode source operating in fore-vacuum pressure range (5–15 Pa), potential is much lower than energy, offering possibility direct treatment insulating materials. It found that non-conducting moderately high range, charge on surface neutralized mainly ions from volume discharge established between negatively charged and grounded walls vacuum chamber. This allows (heating, melting, welding) ceramics other semiconductor

We describe the design, electronics, and test results of a simple low-cost time-of-flight ion charge-to-mass analyzer that is suitable for source characterization. The method selects short-time sample beam whose composition then separated according to velocity detected by remote Faraday cup. detachable device has been used rapid analysis beams accelerated voltages up about 100kV.

Cathodic arc plasmas are considered fully ionized and they contain multiply charged ions, yet gaseous metal neutrals can be present. It is shown that cause a significant reduction of the ion charge states as measured far from cathode spots. Several materials were used to study evolution mean state function time after ignition. The type material, current amplitude, intentionally increased background gas, additional surfaces placed near plasma flow, other factors influence degree because all...

This paper presents the results of time-of-flight mass spectrometry studies elemental and mass-to-charge state compositions metal ion beams produced by a vacuum arc source with compound cathode (WC–Co0.5, Cu–Cr0.25, Ti–Cu0.1). We found that beam composition agrees well stoichiometric material from which is derived, maximum charge different plasma components determined ionization capability electrons within spot plasma, common to all components. The spectrum features greater fraction multiply...

The angular distribution of the different cathode materials and gaseous ion flow from vacuum arc plasma is investigated. A metal-vapor-vacuum-arc-type source a time-of-flight mass spectrometer were used. experiments performed using range materials, including C, Al, Zn, Cu, Ti, Co, Cr, W, Pb, <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{Cu}_{0.7}\hbox{Cr}_{0.3}$</tex></formula> ,...

We present research results on vacuum arc plasma produced with multicomponent cathode made of several different elements. The ion mass-to-charge-state spectra the plasmas were studied by time-of-flight spectrometry. angular distributions species measured, and kinetic energy their directed (streaming) motion was determined. It is shown that fractional composition ions components in flow from spot closely matches content these composite cathode. charge states various are determined average...

We report on our work directed towards increasing the power density of focused electron beam produced by a forevacuum-pressure plasma-cathode source at pressure 10–30 Pa. have optimized geometry plasma discharge system, emission channel and acceleration gap, simultaneously increased voltage. The achieved was 106 W cm−2, an order magnitude greater than that typical forevacuum sources, is quite sufficient to allow use these beams for treatment high-temperature bulk dielectrics.

The industrial quadrupole RGA-100 residual gas analyzer was modified for the research of electron beam-generated plasma at forevacuum pressure range. standard ionizer replaced by three electrode extracting unit. We made optimization operation parameters in order to provide maximum values measured currents any ion species. successfully tested with beam argon, nitrogen, oxygen, and hydrocarbons.

The status of experimental research and ongoing development plasma cathode electron guns in recent years is reviewed, including some novel upgrades applications to various technological fields. attractiveness this kind e-gun due its capability creating high current, broad or focused beams, both pulsed steady-state modes operation. An important characteristic the gun absence a thermionic cathode, feature which leads long lifetime reliable operation even presence aggressive background gas...

Reviews the properties of electron emission from a gas discharge plasma. Interest in plasma is due to possibility creating reliable and effective sources high-current beams. The constricted arc discharge, vacuum superdense glow crossed E*H fields are used for creation surface. Grid stabilization surface stabilize parameters. Electron current switching increase cathode efficiency. controlled by variation concentration, electrode potential magnetic field. beam source, with 200 keV energy...

The noise of the burning voltage cathodic arcs in vacuum was analyzed for a range cathode materials (C, Mg, Ti, V, Ni, Cu, Zr, Nb, Ag, Hf, Ta, W, Pt, Bi, and Si). Cathodic were generated coaxial plasma source, measured with broadband measuring system. Each measurement by fast Fourier transform, revealing power spectrum ∼1∕f2 all over several orders magnitude frequency f (brown noise). absence any characteristic time down to possible cutoffs at high frequencies supports fractal model spots....