Pleiades Publishing Ltd

In the design of powerful laser-plasma sources of extreme ultraviolet radiation with a gas jet as the target, the problem of degradation of gas nozzles is topical. Degradation is observed due to insufficient distance from the generation zone of the laser-induced spark to the nozzle exit. The comprehensive solution to this problem is proposed by forming the laser-induced spark in the density jumps that are generated upon deceleration of the supersonic gas jet. In such a density jump, the laser-induced spark is obtained and measurements of emission radiation intensity are performed.

The dispersion of surface plasma oscillations of a Ge(111)-(2×8) single crystal face was studied by electron energy loss spectroscopy. The experimental data are indicative of a reduced density in the surface layer, which confirms the existing adatom model of the 2×8 surface superstructure.

It is suggested to use a longitudinal magnetic field for changing the polarization of particles (electrons, positrons, muons) in the beam of a storage ring. The change from vertical to longitudinal polarization by single or multiple switching of the longitudinal field for a certain time interval is considered.

The process of voltage distribution over serially connected elements of a high-power semiconductor current interrupter in the stage of current breakage is studied within the framework of a previously developed physicomathematical model. It is established that a mechanism is operative that provides for the voltage drop leveling between unit structures of the p +-p-n-n + type with various depths X p of the p-n junctions. The mechanism is related to the fact that the formation of a strong field region on the stage of current breakage in the unit structures with larger X p begins later, but the expansion of this region proceeds faster than the same processes in the units with smaller X p .

The feasibility of efficient focusing of high-power pulsed X-ray radiation generated by explosive electron emission from carbon nanoclusters is shown by direct experiments with the use of polycapillary X-ray optics. It is shown that the X-ray spot in the focus of the polycapillary lens can be reduced to 1/20 of its initial size.

The first results obtained in engineering research into power heterostructure field-effect transistors operating under zero gate bias are detailed. At a frequency of 10 GHz in pulse mode under gate voltages ranging from −0.2 to +0.2 V, transistors with L-shaped gates with a length of about 0.3 μm and a width of 0.8 mm exhibited a specific power in excess of 1.6 W/mm at a gain in excess of 11 dB and a power-added efficiency of more than 40%.