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Measurements of the energy of an electron beam in an electron beam source with an explosive-emission cathode, a plasma anode and a foil window, providing the extraction of an electron beam with a cross-section of (100–200) cm2 into the atmosphere, have been performed. The high voltage source was a Marx generator based long lines with matched loads. The energy values were calculated from the results of measurements of the temperature of a beam collector placed in vacuum using thermistors and an infrared imager. At an accelerating voltage of ~ 200 kV, a current of (1–2) kA, and an electron beam duration of 5 μs, the maximum values of the energy released in the collector with a cross section of 74 cm2 were (650–850) J/pulse. A decrease in the current and energy of the beam was recorded approximately by a factor of two after passing through an AMG-2n aluminum-magnesium foil with a thickness of 30 μm. The use of infrared imager for recording the beam structure in the plane of the output window in air has been tested.

The results of experiments on obtaining high-current radially converging extended electron beams in a vacuum diode of an electron accelerator, which is intended for excitation of a gas laser, are presented. To reduce the magnetic field in the diode and its influence on the beam formation, in addition to magnetically shielding plates that sectionalize the diode into two magnetically shielded diodes, small-diameter rod current returns were used. Cathodes with wide concave emitting units, which provided a high degree of filling the output windows with the electron beam, were used. The rods are installed in holes between the emitting units and connect the cell ribs to the vacuum-chamber wall. A significant decrease in the angles of electron entry into the foil was observed. It is shown experimentally that mounting the current returns results in a decrease in the magnetic field in the diode, while breakdowns and a decrease in the electron-beam current-pulse duration are absent. At a diode voltage of 550 kV, electron beams with a current of 240 kA, a beam energy in the diode of 20 kJ, and an extracted-beam energy transported through the foil of 6.5 kJ were obtained. The possibility of increasing the electron-beam energy, which is transferred from the diode to the gas-filled cell, by a factor of at least 1.2 was demonstrated.

The results of the experimental studies of the high-power e-beam accelerator producing six radially convergent electron beams are presented. The studies are aimed to increase the energy of the electron beam transported through the foil into the gas-filled chamber by using the rod-shaped current returns in the diode at small inter-electrode gaps. Installation of these rod current returns shields the periphery regions of the diode from the current field in the central part thus reducing the field at the diode edge. The inter-electrode distance, the shape, and the sizes of the cathodes are chosen by taking into account the magnetic field reduction in the diode. It is shown that in such type of the diode the electrons impact the foil almost normally to its surface, and the electron beams enter the output windows completely. Such type of the diode allows increasing the efficiency of the electron beam energy transfer into the gas by 30%.

Results of the physical simulation and numerical calculations of magnetic field of the high-power vacuum diode with a large electron-beam cross section in the absence and with diode-installed return-current conductors in the form of rods are given. It is shown that the use of rods decreases the magnetic induction at the edge of the beam, while the field in the central part of the diode increases. It is found that the distribution of the magnetic field in the interelectrode cathode-anode gap in the presence of rods depends on the gap length between the back side of the cathode and the walls of the vacuum chamber. The location of the rods that halves the induction of the magnetic field at the edge of the cathode with the reasonable induction increase in the central part is found.

The design and results of tests of a generator developed for obtaining a current of positive polarity with a duration of the first half-period of 110–130 ns, an amplitude of 40–70 kA in the single-pulse mode, and an amplitude of 30 kA at a pulse repetition rate of 10 Hz for 5 min in an inductive-resistive load of 300 nH, 1 Ω are presented. The setup has been assembled according to a scheme with an intermediate energy storage. The primary storage is a 10-stage Marx generator, and a capacitor with water insulation performs the function of the intermediate storage.

An excimer laser system having an output aperture diameter of 40 cm and consisting of five lasers, three of which are excited by an electric discharge and the remaining two by an electron beam, is built. The first laser produces a 308-nm radiation with a duration of 200—250 ns, a spectral linewidth of 0.9 cm-1 and the beam divergence close to the diffraction limit. This pulse is amplified in the active media of the other lasers. As a result, radiation with an energy of 5 J, spectral linewidth 0.9 cm-1 and beam divergence 37 μrad is produced at the output of the third laser. The output energy of the entire system amounts to 330 J and the pulse duration is 200—250 ns.

Two-high power excimer laser systems with square (25 × 25 cm) and circular (with a diameter of 40 cm) cross sections of the output laser beam are described. The first (second) system consists of four (five) excimer lasers. The experimental results on the generation of the high-quality high-power laser pulses are presented. Laser beams with a pulse duration of 1–250 ns, a divergence of 0.01 mrad, a spectral line width of 0.01 cm−1, and a pulse energy of up to 330 J are obtained.

Schemes of high-power electron-beam-pumped pulsed lasers on dense gases and the experimental results on the lasing on XeCl*, KrF*, and HF molecules are presented. The energy input and the kinetic processes in the active medium of the electron-beam-excited XeCl laser are calculated. Radiation pulse energies of 1900, 200, and 90 J are obtained at wavelengths of 308 nm, 2.8 μm, and 249 nm, respectively.

A 308-nm XeCl laser with an active volume of 600 L is studied experimentally. The laser is pumped by a radially convergent electron beam from an accelerator with vacuum insulation. The output energy of 1.9 kJ and power of ~7 GW are achieved upon pumping the Ar—Xe—HCl mixture. The laser pulse FWHM is ~250 ns.

A high-current accelerator for pumping of the 200-L excimer laser is developed, providing electron energy of 550 keV, a diode current of 320 kA, and an e-beam current of 250 kA. The high-voltage part of the accelerator consists of two linear transformers with a stored energy of 98 kJ. To reduce the influence of the self-magnetic field on e-beam formation, the vacuum diode is divided into six separate magnetically isolated diodes.

Experimental and theoretical investigations were made of the excitation and emission from a high-power HF laser pumped by a nonchain chemical reaction initiated by a radially converging electron beam. The distribution of the specific radiation energy in the output beam was determined and the distribution of the input energy over the laser chamber cross section was calculated for various gas mixtures. The space-charge field influenced the input energy distribution. The output radiation energy of a mixture of the SF6 : H2=8 : 1 composition was ~115 J at a pressure of 0.45bar when the active volume was ~30 litres, the efficiency relative to the input energy was ~7%—8%, and the distribution of the radiation energy over the output beam cross section was relatively uniform. For the same input energy, because of the high density of SF6, a pressure jump in SF6— H2(D2) mixtures resulting from the combined effect of the electron beam injection and the chemical reaction was several times less than in active mixtures of exciplex lasers.

When a voltage pulse is applied to an interelectrode vacuum gap, bunches of transient plasma are formed on the cathode which are efficient emitters of charged particles. The present review gives the results of investigations of the cathode-plasma emissivity, the stability conditions of the high-voltage discharge phase, the mass-charge composition of the cathode plasma and its relationship to the threshold current of the cathode material, and the conditions for forming an anode plasma and its influence on the duration of the high-voltage discharge phase. Examples are given in which the results are used to create a wide range of electron and ion beams and current beakers.

A high-power compact laser using XeCl* and KrF* molecules has been constructed and tested. At an output pulse length ~300 ns at half-maximum, output energies of 110 and 90 J were obtained at the wavelengths λ =308 and 249 nm, respectively. When the electron beam is injected from four sides into a mixture at a pressure between 1 and 3 atm, the energy density of the radiation is uniform over the cross section of the output beam.

A 250 J/210 ns four-stage XeCl laser system named Photons has been developed. Five lasers in MOPA chains characterized by different pumping techniques are described. Also, the main experimental results of the Photons are given.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The results of the experimental study of UV and IR lasers pumped by electron beams are presented. The accelerators with radially convergent electron beam for pumping gas mixtures under pressure up to 3 atm were used. Laser radiation energies of up to 2 kJ, 200 J, 100 J, 50 J have been obtained at the wavelengths of 308 nm, ~2.8 μm, 250 nm and 1.73 μm, 2.03 μm, correspondingly.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The results are presented of experimental and theoretical investigations of excitation and generation of the HF laser pumped by nonchain chemical reaction initiated by a beam of electrons as well as of the KrF and XeCl lasers pumped by beams of electrons. The effect of the volume charge field on the distribution of energy over the cross section of a laser cell and of the radiant energy density over the cross section of an output laser beam in mixtures with different concentrations of halogen is analyzed. The output energy density distribution over the beam cross section for lasers excited by the radially convergent beam of electrons and the total pump energy are determined. The pump energy distribution over the laser cell cross section and the total pump energy in various gas mixtures are calculated.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The results of an experimental study of the laser action on XeCl*, KrF*, and N2 molecules and by the atomic transitions of xenon and neon are presented. Laser radiation energies of 110, 90, 3, 100, 50, and 0.5 J have been obtained at (lambda) equals 308, 249, 358, 1730, 2030, and 585 nm, respectively. The experiments were carried out on two accelerators producing radially convergent electron beams, that pumped laser chambers 20 mm in diameter with a beam current of FWHM duration 0.3, 30, and 100 microsecond(s) .© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Linear electric circuit with constant parameters becomes a nonlinear one with parameters variable in time after vacuum discharge gap is connected to it. Change of discharge parameters occurs by cycle. Full vacuum discharge cycle includes predischarge, spark, arc phases and current break phase (Fig. 1). Discharge development by incomplete cycle as well as development of one and the same discharge by several parallel channels with different cycles are possible. Every moment discharge current I is limited by one ofthe factors and namely - cathode emission ability L, plasma emission ability I, vacuum gap conductivity P. outer circuit resistance R -but it can not be limited by simultaneous infidence of several these factors. Fragment of the scheme (Fig.2) reflecting succession of turning on of current limiting factors may present how the process ofevery discharge goes on.

A 308-nm XeCl laser with an active volume of 200 L is described and the results of its tests are presented. The output energy of 660 J is obtained by pumping the Ar : Xe : HCl = 1520 : 40 : 2-Torr mixture. The FWHM laser pulse duration is ~350 ns. The nonuniformity of the laser-radiation density distribution over the cross section of the output beam in the near-field zone is within 10%. An accelerator that forms a radially converging electron beam with an electron energy of up to 550 keV, a vacuum-diode current of up to 320kA, a beam-current pulse duration of ~1 μs, and a beam current of up to 250 kA is used to pump the system. Two linear transformers with a 98-kJ energy stored in the primary storage serve as high-voltage sources. To reduce the effect of the self-magnetic field on the beam formation, the vacuum diode is divided into six diodes magnetically insulated from each other.

The efficiency of gas liberation from the anode in the high-voltage stage of a vacuum discharge is measured. At the beam current density ? 10 A · cm-2, the gas liberation factor reaches ~1-10 molecule/electron. Gas liberation from the anode is the main factor that induces the discharge to go to a low-voltage arc stage and causes the limitation of the beam current duration. On lowering the concentration of the gas liberated in the electrode gap, the beam current duration is limited by spontaneous breaks of current and reaches ~-1 s.