I. N. Konovalov

Relativistic Gigawatt BWT microwave pulse duration increased upon treating the slow-wave structure surface with a low-energy high-current electron beam

A new method of insulator surface treatment, which allows the electric strength of the material to be increased, is proposed and verified. Using this method for treating the slow-wave structure of a relativistic backward wave tube (BWT), the microwave pulse duration was increased from ∼6 to ∼30 ns at an output BWT radiation power of 3 GW.

High-power excimer laser systems

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.

Wide-aperture electric-discharge XeCl lasers

Experimental results of long-pulse generation in X-ray preionized XeCl lasers with the 9x7 cm2 and 5.4x3 cm2 apertures are described. The lasers operate in the Ne-Xe-HCl mixture with the pressure up to 4 atm. Paper-oil pulse forming lines and a rail-gap switch for the discharge pumping were used. A 3.5 and 10 J output with the optical pulse duration of 250-300 ns (FWHM) has been extracted.

KrF laser system with a wide range of wavelength tuning

Development of KrF laser system for lidar designed for detection of the compound molecules containing a nitric oxide is presented. The system consists of the master oscillator and the amplifier operating at pulse repetition rate up to 100 Hz. Laser radiation having energy up to 0.2 J and bandwidth of 2 pm is smoothly tuned in a spectral range of 247.6-249.5 nm.

The development of a long-pulse excimer laser system

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.

Stability of discharge in excimer gas media with high specific pump powers

The results of studies on the formation of a volume discharge in an electric-discharge XeCl laser with a maximum specific pumping power of 4.7 MW/cm3 are presented. It is shown that with a half-cycle duration of discharge current of 20 ns, the radiation pulse duration on the base is 100 ns. A good agreement between the experimental and numerical results obtained with the XeCl laser was demonstrated. Plasma-chemical processes occurring in a volume discharge at a maximum electron concentration in the plasma of ~ 7×1015 cm-3 are considered.

A wide-aperture x-ray source with high intensity and uniformity of radiation

The results of experimental research on an x-ray source intended for preionizing the laser mixture in wide-aperture electric-discharge excimer lasers are presented. An experimental prototype of the source in which an x-ray radiation pulse is formed in an inverted-type vacuum diode during braking of accelerated electrons in a tantalum foil has been developed. It is shown that the use of a metal-dielectric cathode allows generation of x rays with nonuniformity of the intensity distribution within limits of 10% at an energy of quanta no higher than 55 keV and a radiation exposure dose 160 mR.

Experimental study on a long-pulse excimer laser system

A four-stage XeCl laser system named Photons has been developed for studying laser interaction with materials. The Photons are outlined and preliminary results characterizing the system are given. The master oscillator Photon-1 can provide “seed” light with laser energy of about 40mJ, pulse duration of about 250ns and good beam quality of nearly diffraction-limited divergence angle and narrow line width less than 1 cm-1 for whole system. The output energy of laser system of 251J has been obtained by four-stage amplification. The synchronization among five lasers is realized by the combination of low voltage timer, high voltage synchronic generators and compensated cables. The demonstration shows Photons good operation with low jitter of less than ±20ns.

Generation in electric-discharge XeCl lasers of a high energy long pulses

Experimental results of long-pulse generation in X-ray preionized XeCl lasers with a 9 x 7 cm2 and 5.4 x 3 cm2 apertures are described. Lasers operate at Ne-Xe-HCl mixture with pressure up to 4 atm. Paper-oil pulse forming lines and rail-gap switch for discharge pump was used. An 2 - 10 J output with optical pulse duration of 250 - 300 ns (FWHM) have been extracted. Problems and peculiarities of long laser pulse formation are discussed.

10-J long-pulse electric-discharge XeCl laser

An X-ray preionized XeCl laser with a large aperture (9x7 cm) is described. Laser operates at Ne-Xe-HCl mixture with pressure up to 4 atm. Paper-oil pulse forming lines and rail-gap switch for discharge pump was used. 10 J output with optical pulse duration up to 300 ns (FWHM) have been extracted from active volume 5.4 l with an electric efficiency 1.2%.