The design and operating principle of a pulsed proton source based on a Penning-type reflective discharge with a cold hollow cathode is described. Gas-discharge systems with a small aperture hollow cathode ensure the formation of inhomogeneous plasma with increased density on the discharge chamber axis and in the emission electrode area and are characterized by a relatively low discharge voltage. Such a discharge system fully meets the requirements for plasma generators of charged particle beam sources with high current density. The results of studies on the influence of key parameters of the discharge system: working gas pressure, magnetic field induction, geometry of the hollow cathode on the discharge, and emission characteristics of the source are presented.

Pure boron coatings have been deposited on stainless-steel substrates using a planar magnetron with a thermally insulated target of pure crystalline boron in a direct current discharge of up to 50 mA in an argon atmosphere. The magnetron was designed to be used as a component in an electron-ion-plasma test bench for in situ monitoring of boron deposition growth using synchrotron radiation from the VEPP-3 electron storage ring at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences. Using this magnetron, we have fabricated boron films with thickness up to 1.5 μm and studied their surface morphology, mechanical properties, and coating composition.

We describe here the electrode system, design, and parameters of an ion source based on a Penning-type hollow-cathode reflex discharge developed for generation of proton beams. Especially for proton beam generation, a modified geometry of both hollow and reflex cathodes was fabricated. The working gas is molecular hydrogen. Ion extraction and beam formation are performed using a three-electrode single-aperture optical system with a 3-mm diameter emission aperture. At an accelerating voltage of 33-35 kV and a discharge current of 0.55 A in continuous mode, the ion beam current was 15-17 mA, and in pulsed mode, at a discharge current of about 2 A, the beam current was 55 mA. The beam consists mainly of H+, H-2(+), and H-3(+) ions, with the proton (H+) fraction up to 27% in continuous mode and 40% in pulsed mode

The features of the probe technique are described and the results of measuring the parameters of plasma generated by a planar magnetron sputtering system with a pure boron target during coating deposition are presented. A feature of probe measurements was the use of heating the collecting surface of a single Langmuir probe. Heating led to a decrease in the electrical resistance of the boron film on the surface, which made it possible to carry out in situ probe measurements of the magnetron discharge plasma parameters during the entire process of boron coating. Keywords: plasma parameters, probe method, planar magnetron, boron films.

The paper presents the results of a study of the current-voltage characteristics and optical emission spectra of plasma of a atmospheric pressure pulsed discharge plasma at a frequency of several tens of kilohertz and a pulse duration of up to 10 μs, in the mode of generation of plasma flows containing metal particles. The features of the plasma generator conclude in combination of the design of electrodes, as well as the modes of electric and gas supply of the discharge system. The cathode is a crucible containing a melting insert which allows the discharge operation in a low-current form with a current of 40 mA to 1 A, at a sufficiently high voltage of 150 to 200 V, without transition to arc discharge mode. Such parameters make it possible to generate atomic flows of a melting cathode insert, which are blown out by a jet of working argon gas, pumped at a flow rate of 1 l/min, outside the discharge system. The entry of a metal component into a gas-discharge plasma affects the parameters of the discharge operation, as well as the properties of its optical emission. In the context of this phenomenon, the spectral distributions of the intensity of optical radiation corresponding to the lines of magnesium, indium, and zinc were investigated, as well as their time dependence during the current pulse period operation, in relation to the identification of physical features leading to stable generation of flows of metal atoms at atmospheric pressure.

Представлен сравнительный анализ процессов функционирования и нанесения покрытий вакуумным и газовым магнетроном в частотно-импульсном режиме самораспыления с медной и серебряной мишенями.Осо бенностью проведенных исследований является использование единого устройства, функционирующего при различных давлениях аргона: 2 10-3 Торр и 10-5 Торр.Сравнение характеристик устройства при таких давлени ях и свойств полученных покрытий на поверхности образцов показало

In this study, boron thin films were deposited on metal substrates using planar direct current (DC) magnetron sputtering with a pure boron target. Boron has high electrical resistance, severely impeding its application in a magnetron discharge; however, it is a semiconductor and its resistance decreases as the temperature increases. We used a planar magnetron with a boron target that was heated in a DC discharge current up to 50 mA in argon and nitrogen at a pressure of 2-3 mTorr. For these discharge parameters, at a distance of 5 cm from the target the boron deposition rate was about 150 nm/h. Thin boron films with thickness up to 1 μm were obtained and their surface morphology was studied. The deposition technique and the properties of the films are discussed.

Planar magnetrons with a heated crystalline boron target are promising for depositing boron coatings intended for a wide range of scientific and industrial applications. The promotion of this type of magnetrons requires an in-depth investigation of the coating deposition process. A new version of such a magnetron is created for the vacuum electron-ion-plasma (VEIP) test installation for in situ synchrotron radiation monitoring of the boron coating synthesis. The paper proposes the design and parameters for this magnetron and discusses the boron coating deposition using the VEIP test installation.

Investigation of the processes involved in the synthesis of magnesium oxide and zinc oxide powders using the thermal effects of an atmospheric-pressure glow discharge plasma in an inert gas flow are described. The discharge operates in a repetitively pulsed mode with pulse repetition rate of several tens of kilohertz and pulse duration up to 12 mu s, discharge current of 600 mA and voltage up to 300 V. These parameters lead to thermal erosion of magnesium or zinc inserts in a molybdenum crucible. The chemical and phase composition of the erosion products were determined using TEM/EDS and X-ray diffraction analysis, and the composition of the plasma was assessed by optical emission spectrometry. This experimental approach allows fabrication of powders of these metal oxides with characteristic particle size 10-50 nm, and the formation of coatings of these materials in a one-step process.

The features of the probe technique are described and the results of measuring the parameters of plasma generated by a planar magnetron sputtering system with a pure boron target during coating deposition are presented. A feature of probe measurements was the use of heating the collecting surface of a single Langmuir probe. Heating led to a decrease in the electrical resistance of the boron film on the surface, which made it possible to carry out in situ probe measurements of the magnetron discharge plasma parameters during the entire process of boron coating.

In an ion source based on a pulsed planar magnetron sputtering discharge with gas (argon) feed, the fraction of metal ions in the ion beam decreases with decreasing gas pressure, down to the minimum possible working pressure of the magnetron sputtering discharge. The use of a supplementary vacuum arc plasma injector provides stable operation of the pulsed magnetron sputtering discharge at extremely low pressure and without gas feed. Under these conditions, the pressure dependence of the gaseous ion fraction displays a maximum (is nonmonotonic).

В докладе представлены результаты исследований импульсных источников электронов (электронных пушек), разрядный механизм которых основан на несамостоятельном высоковольтном тлеющем разряде. Электронные пушки с несамостоятельным высоковольтным разрядом можно разделить на два основных типа: системы с чисто ионно-электронной эмиссией с массивного (зачастую плоского) катода, бомбардируемого ионами, и системы с полым катодом. В последнем типе электронной пушки плазма, которая генерируется внутри полого катода вследствие бомбардировки ионным пучком, действует как эмиттер электронного пучка. Источником бомбардирующих ионов является анодная плазма вспомогательного разряда. Ионы извлекаются из этой плазмы и ускоряются к катоду, имеющему высокий плавающий потенциал в несколько десятков кВ. Электроны, эмитируемые катодом, ускоряются тем же полем по направлению к аноду. Анодная плазма, ее параметры, характер и устойчивость горения разряда является определяющими в работе электронного источника с ВТР, поэтому в докладе определенное внимание уделено генератору анодной плазмы, построенному на основе геометрии плазменного ускорителя с замкнутым дрейфом электронов. С помощью зондовых методов исследования измерены основные локальные параметры анодной плазмы – температура электронов и концентрация ионов.

The paper reports on recent experimental studies of the operation of a vacuum arc ion source with a hot pressed lanthanum hexaboride (LaB6) rod cathode which has a low porosity and almost perfect density (4.65 g/cm 3 ). Under normal conditions the resistivity of LaB6, being a refractory ceramic material, is very low and its conductivity is similar to that of metals, and the behavior of cathode spots on the surface of LaB6 is the same as their behavior on pure metals. From cathode spots, the vapors, charged particle flows, a large flow of macroparticles and small cathode fragments is emitted. Such macroparticles bombard the electrodes of the ion-optical system of the source and evaporate, forming a dense plasma, with the result that the acceleration gap is broken down within several milliseconds after vacuum arc extinction. For reducing the flow of macroparticles, the discharge system of the source is equipped with a mechanical direct-flow filter in the region of cathode plasma expansion. The loss of plasma in the filter is compensated by the fields of a permanent magnet and solenoid. The vacuum arc source produces a pulsed (about 300 μs) boron–lanthanum ion beam with a current of 600 mA and diameter of 4 cm with no gas supply.

We describe our work on tungsten disilicide film deposition by planar magnetron sputtering at low operating gas pressure (down to 0.08 Pa). The sputter target was a tungsten disilicide composite with diameter 125 mm, and the DC magnetron current 0.1-1 A. We have explored the dependence of film homogeneity over the 100 mm diameter substrate on substrate temperature and distance from the magnetron, and the spatial distribution of ion current density and the effect of operating pressure on the roughness and resistivity of the films.

The principle of operation and the characteristics of the experimental equipment intended for the generation of boron ion plasma and beams are presented. The equipment comprises a vacuum arc source of boron ions with boron isotope separation in a magnetic field and a plasma generator for deposition of boron-containing coatings based on a planar magnetron sputter. Common to this equipment is the use of lanthanum hexaboride cathodes, but for planar magnetron, a pure boron cathode heated in the discharge is also used. It is shown that, when silicon wafer is implanted with beams of 10 B + and 11 B + boron isotope ions with doses of 10 14 –10 16 ion/cm 2 , the isotopic effect of the diode properties of the implanted surface is observed. The results of studies of the properties of the obtained boron-containing coatings on model materials: stainless steel, crystal silicon, and E110 (Zr–1Nb) reactor alloy are presented.

The article presents the results of recent experimental studies of spontaneous electron beam modulation with a frequency of several tens of megahertz in a plasma-filled diode. The diode comprises a plasma cathode with a grid-stabilized emission boundary and a plasma anode with an open (conditionally electrodeless) movable boundary. The cathode plasma is formed by a cathodic arc and the anode plasma by toroidal plasma generators based on an anode-layer closed drift thruster. According to our previous studies, the beam current starts to modulate as the arc current goes above 50–55 A at an accelerating voltage of 12–22 kV. Here, we analyze how such electron beam modulation and its frequency are influenced by the grid geometry at a current of about 100–110 A and what methods can be used for its removal. The idea of removal consists in decreasing the effect of the accelerating voltage on the cathode plasma, for example, via a negative current feedback. It is shown that the most efficient modulation suppression is attained when the negative feedback is frequency-dependent and that the modulation frequency decreases to its complete disappearance as the grid mesh size is decreased.

Experiments are reported demonstrating the generation of a wide-aperture electron beam with high-frequency modulation in a plasma-cathode electron source with a diode-type bipolar plasma-filled optical system. The plasma optical system is formed by a plasma cathode (plasma electron emitter) with a grid-stabilized emission surface and a lengthy plasma anode with an open movable plasma boundary. The system with its low impedance and high perveance can provide the required electron beam power density at a relatively low accelerating voltage (tens of kilovolts). The plasma in its anode region is produced by a plasma dynamic device based on a closed drift accelerator. The plasma cathode presents a hollow plasma electron emitter with a vacuum arc plasma generator on the inside. The electron source operates in repetitive pulsed mode at a pulse duration of 100 μs, pulse repetition frequency of 10 pps, and electron emission current of up to 140 A. The experiments show that the beam in the acceleration gap of the plasma optical system gets into high-frequency modulation mostly at an accelerating voltage of 10÷20 kV and arc current greater than 60 A. High-frequency modulation is also observed in the emission current with no plasma in the anode region of the plasma optical system. The basic modulation frequencies are about 18 and 54 MHz.

The report presents an experimental studies of a pulsed vacuum arc discharge operation with pure boron and lanthanum hexaboride cathodes. For the experiments reported here, the arc discharge triggering was carried out due to breakdown on a ceramic button installed in the center of the cathode surface. Pure boron and LaB6 cathodes were tested. The pure boron cathode is a cast rod. The lanthanum hexaboride cathode is a hot pressed rod with small porosity (not more than 1%). Pure boron is a non-metallic element, but a semiconductor with a very high resistivity (2 MOhm×cm) under normal conditions, therefore for the stable discharge operation requires the cathode preheating up to high temperatures. A strong temperature dependence of resistivity and relatively low thermal conductivity lead to the fact that the cathode spot is localized in one place. Lanthanum hexaboride, although it is considered a refractory ceramic material, differs from pure boron in that it has a very low resistivity under normal conditions. Therefore, there is no need to preheat of the cathode for the arc discharge operation. Another difference is that LaB6 has a metallic type of conductivity and behavior of the cathode spots on the surface of the LaB6 cathode is similar to the behavior of the spots on a pure metal cathode. The vacuum arc with boron containing cathodes is accompanied by a large flow of hot droplets - macroparticles, as well as small cathode fragments.

A boron ion plasma can be used to form monoisotopic ion beams containing 100% of 10 B+ or 11 B + ions. In the present work, we study one of the methods that is used to generate such plasmas and which is based on a vacuum arc discharge with a lanthanum hexaboride cathode. Using an ion source based on a vacuum arc discharge and a magnetic separator, we obtained compositionally uniform ion beams of boron isotopes with atomic masses 10 and 11 a.m.u. We performed a separate implantation of 10 B + and 11 B + ions on silicon and zirconium-niobium alloy surfaces with exposition doses up to 5·10 15 cm -2 . The secondary ion mass spectroscopy (SIMS) technique was used to study the implantation profiles of subsurface areas of the materials treated by ion beams. Using identical operation conditions of the vacuum arc as in the case of the ion implantation, the cathode erosion products were deposited on a silicon surface. The scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDS) techniques were employed to analyse the surface microstructure of the cathode and deposited coating as well as their elemental composition.

We have investigated an atmospheric pressure discharge in the argon flow using magnesium, zinc, and boron carbide electrodes and determined the conditions for emission of the aerosol consisting of cathode material nanoparticles suspended in the gas mixture of argon and air. It has been experimentally demonstrated that for the discharge operating in the pulsed mode at a frequency up to 100 kHz and mean power up to 80 W, below the current level required for the transition to atmospheric pressure arc with cathode spots (from several milliamperes to 0.5 A), there exists an operating regime under which the cathode material takes part in the discharge maintenance and formation of the plasma flow. The coatings, produced as a result of aerosol condensation, have been studied using scanning and transmission electron microscopy. Elemental composition of the coatings has been studied using an energy-dispersion spectrometer. With the help of the employed techniques, we have determined that the coatings consist of nanoparticles, of the sizes varying from several to tens of nanometers, agglomerated in larger particles that include, in approximately equal parts, atoms of the cathode material and oxygen. The obtained result opens up new possibilities in generation of combined gas-metal flows under atmospheric pressure for the purpose of producing ultra-disperse powders.