Hydrogen ion source with a cold magnetron cathode and magnetic plasma compression

A hydrogen ion source designed for the injector of a 16-MeV linear proton accelerator with an average beam current of ∼100 μA is presented. New design approaches allowing an improvement in the operating parameters of the ion source are proposed. The results of experimental tests of a source prototype operating in a pulsed mode with a repetition rate of 1–10 Hz and pulse duration of 100–600 μs are described.     

Ion source with a cold magnetron cathode and magnetic plasma compression

The operating principles, design, and characteristics of an ion source with a cold magnetron cathode and magnetic plasma compression are described. The source is intended for the injector of a linear proton accelerator.     

Operational characteristics of a plasma cathode with a grid stabilization in a two-stage ion source

The discharge characteristics and the parameters of the cathode plasma in a two-stage ion source with a grid plasma cathode and a magnetic trap in the anode region are investigated. It is shown that an increase in the gas pressure and the accompanying increase in the reverse ion current in the bipolar diode between the cathode and anode plasmas lead to an increase in the cathode plasma potential and a transition of the cathode into the regime of electron emission from the open plasma boundary. The dependence of the ion current extracted from the anode plasma on the area of the exit aperture of the hollow cathode and the mesh size of the grid plasma cathode is explained. The conditions at which the ion emission current from the anode plasma is maximum are determined. The potential difference at the bipolar diode is measured by using the probe method. It is shown that, when the gas pressures reaches a critical value determined by the mesh size of the grid plasma cathode, the discharge passes into a contracted operating mode, in which the ion current extracted from the anode plasma decreases severalfold.     

Design of triode extraction system for a dual hollow cathode ion source

A triode extraction system is designed for a dual hollow cathode ion source being developed at the Institute of Heavy Ion Physics,Peking University.Basic parameters of the plasma are selected after examining the operation principle of the ion source,then the triode extraction system is designed and optimized by using software PBGUNS (for Particle Beam GUN Simulations).The physical design of the system is given in this paper.     

Design of triode extraction system for a dual hollow cathode ion source

A triode extraction system is designed for a dual hollow cathode ion source being developed at the Institute of Heavy Ion Physics, Peking University. Basic parameters of the plasma are selected after examining the operation principle of the ion source, then the triode extraction system is designed and optimized by using software PBGUNS (for Particle Beam GUN Simulations). The physical design of the system is given in this paper.     

High-voltage pulsed discharge in an electron source with a plasma cathode

The nature of and mechanism for producing a high-voltage discharge in an electron source with a plasma cathode are investigated. The possibility of generating pulsed electron currents with an amplitude of 10³–10⁴ A and a length of 10^–6 sec is considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 117–121, October, 1973.The authors thank B. M. Koval'chuk for help in developing the experimental arrangement and G. A. Mesyates for constant attention to the work and discussion of the results.     

Interaction of cathode plasma with the cathode surface in an electron source with explosive electron emission

The interaction of the plasma formed at emission centers of an electron source using explosive electron emission with the cathode surface is studied. It is found that the plasma flux does not flow around obstacles located in its path and is effectively deionized upon incidence on the wall.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 26–29, November, 1981.     

Generation of a homogeneous plasma and wide ion beams in a penning system with a nonequipotential cathode

A study is made of the possibility of controlling the spatial distribution of the degree of ionization in a modified Penning cell with a cathode divided into several sections that are at different potentials. It is shown that an almost uniform plasma can be produced when applying an optimal potential of the control electrode. This enables the generation of wide ion beams in this system. An ion extraction efficiency of several tens of percent is achieved, which is substantially higher than in conventional ion sources.     

Characteristics of a multi-keV monochromatic point x-ray source based on vacuum diode with laser-produced plasma as cathode

Temporal, spatial and spectral characteristics of a multi-keV monochromatic point x-ray source based on vacuum diode with laser-produced plasma as cathode are presented. Electrons from a laser-produced aluminium plasma were accelerated towards a conical point tip titanium anode to generate K-shell x-ray radiation. Approximately 10₁₀ photons/pulse were generated in x-ray pulses of ∼18 to ∼28 ns duration from a source of ∼300 μm diameter, athυ = 4.51 keV (K _α emission of titanium), with a brightness of ∼10²⁰ photons/cm²/s/sr. This was sufficient to record single-shot x-ray radiographs of physical objects on a DEF-5 x-ray film kept at a distance of up to ∼10 cm.     

强流磁约束金属离子注入源

设计和制造了适合工业应用的强流金属离子源。离子源的电弧阴、阳电极之间和放电室壁采用永磁体阵列形成导流、屏蔽磁场,改进了电弧的放电特性和提高等离子体密度。离子注入源在加速电压为30kV、50 Hz 条件时,平均束流流强约为30mA,调试结果表明附加磁场提高了离子源性能。     

Discharge initiation in a hollow-cathode plasma source of electrons

Experimental results on discharge initiation in a hollow-cathode plasma source of electrons are reported. The discharge is initiated by ions flowing out from the accelerating gap into the discharge region. The ions are generated by a high-voltage glowing discharge occurring in the accelerating gap at a pressure of more than 2 Pa and a voltage of no less than 2 kV. It is shown that an increase in the ion-electron emission coefficient, which can be raised by properly choosing the gas-metal pair, decreases the threshold ion current initiating the discharge at a fixed discharge voltage.     

Energy losses and scattering of fast electrons in a dense plasma

This paper describes an algorithm for the calculation of specific energy losses and multiple scattering of fast electrons in a plasma, taking into account the interaction of the electrons of the beam with the bound and free plasma electrons and with the plasma. Results are presented of calculations for aluminum and lead plasmas with density 0.001-1 of normal and with temperature up to 1 keV for initial electron kinetic energy of 1 MeV. The energy-loss distribution in an aluminum plasma is calculated by the Monte-Carlo method.Tomsk Polytechnic University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 112–116, September, 1993.     

Transition radiation of fast electrons as a broadband vacuum-ultraviolet radiation source

The characteristics of a possible radiation source in the vacuum-ultraviolet and soft X-ray range based on the transition radiation of electrons with an energy of about 100 keV are calculated. The possibilities of enhancing the radiation yield in the geometry of the glancing interaction of electrons with a target are analyzed. The possibility of creating a source with a yield on the order of 10^?5 photon/(eV sr) per electron is demonstrated.     

Extension of the gas-pressure operating range and increase in the lifetime of the plasma cathode grid of an ion source

A new scheme of a gas-discharge system is proposed for a basket-type ion source with a plasma cathode in which the electrons are emitted from the expanded anode part of a constricted hollow-cathode glow discharge bounded by a grid electrode. The modified electrode system of the ion source made it possible to enlarge the surface area of the plasma cathode grid and the aperture of its cells, thereby providing stable ion emission from the discharge plasma within a wide gas-pressure range and substantially (by one order of magnitude) increasing the grid lifetime. The operation of the plasma cathode in the free and forced emission modes is examined, and the energy efficiency of ion generation in the gas-discharge system under study is evaluated.     

Limiting operating pressure in a plasma source of electrons with hollow-cathode discharge

Results of an experimental study of the correlation between the accelerating gap parameters in a plasma source of electrons and the limiting magnitudes of the gas pressure and the voltage applied to the gap are presented. It has been found that the electron beam increases the electrical strength of the gap.     

Interaction of a plasma source with an ambient plasma

Summary Plasma sources are used to control spacecraft potential and, in general, to improve the electrical contact between a charged body and the space plasma. In the present paper we address the problem of the interaction of a plasma source with the ambient plasma. The source is supposed to be positively charged with respect to the ambient. A self-consistent collisionless one-dimensional fluid model is sketched and some of the results obtained are then presented and discussed. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

Electrostatic double layers in a warm negative ion plasma with nonextensive electrons

The electrostatic double layer (DL) structures are studied in negative ion plasma with nonextensive electrons q-distribution. The extended Korteweg–de Vries (EKdV) equation is derived using a reductive perturbation method. It is found that both fast (compressive) and slow (rarefactive) ion acoustic (IA) DLs can propagate in such type of plasmas. The effects of various plasma physical parameters; such as nonextensivity of electrons, presence of negative ions, temperature of both positive and negative ions and different mass ratios of positive to negative ions on the formation of DL structures are discussed in detail with numerical illustrations.     

Child''s law for fast ion emission from a laser-generated plasma

Observations have been made of fast ions emitted from a laser generated plasma. Ion flux and energy have been measured as functions of laser intensity and laser focusing position. The fast ion flux is shown to obey Child's law.     

The segmented hollow cathode discharge: a pumping source for UVmetal ion lasers

We have investigated the operation of a high-voltage segmented hollow cathode discharge which is an efficient pumping source for ultraviolet metal ion lasers. We present the photographically recorded visual appearance of the discharge and the spatial distribution of the ionization source obtained from Monte Carlo simulation of the electrons' motion. Both results show that the high voltage of the segmented hollow cathode discharge and the curved cathode surfaces result in a strong focusing of the fast electrons even at the relatively high operating pressure