Investigating the influence of a Forbush decrease on the detected flux of high-energy muons

The effect of Forbush decreases was studied for a flux of high-energy muons with a threshold of 220 GeV detected by the Baksan Underground Scintillation Telescope (BUST) of the Institute for Nuclear Research, Russian Academy of Sciences.     

Experimental test of the nonlinearity of the characteristics of the piezoelectric transducer of the phase modulator of a fiber ring interferometer at small sinusoidal deformations

We show that the level of the second harmonic of sinusoidal modulation resulting from the non-linearity of the characteristics of piezoelectric transducer does not exceed0.005–0.0005% for deformations ranging from10−8 to10−6. The influence of the nonlinearity of the characteristics of a piezoelectric transducer used as a modulator of the optical length of the loop of a fiber ring interferometer on the accuracy parameters of the latter is analyzed. It is shown that the given level of the second harmonic does not lead to a significant shift of the zero of the interference of counterpropagating waves at the interferometer output. Institute of Applied Physics, Russian Academy of Sciences; Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 2, pp. 198–200, February 1999.     

Experimental observations of the stepped Cu-atom ionization in the active medium of a Cu laser

An optogalvanic effect in a pulsed copper-vapor laser is discovered and investigated. It is found that the generalized deexcitation rate constant of the resonance level to the ionization state of the active medium is <σv>∼ (3±1)·10⁻⁷ cm³·s⁻¹. An optothermal effect caused by the hysteresis of the optogalvanic phenomenon is found experimentally. The feasibility of measuring the stepped ionization constants of resonance and metastable states for a number of metal atoms in a pulse-discharge plasma is discussed. Institute of Physics of Semiconductors of the Siberian Branch of the Russian Academy of Sciences; Institute of Atmospheric Optics of the Siberian Branch of the Russian Academy of Sciences; Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences; Tomsk State University. Translated from Izvestiya Vysshikh Uchebhykh Zavedenii, Fizika, No. 8, pp. 57–62, August, 1999.     

Electron beamexcitation of wide-aperture XeCl lasers

This paper presents the results of studies aimed at seeking efficient modes of electron beam excitation ofXeCl lasers with an active volume of some tens of liters. It has been shown that a lasing efficiency of about 4% is realized at an excitation pulse duration of 300 ns with a power of 200–400 kW/cm³. Institute of High-Current Electronics, Siberian Division of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 29–33, April, 2000.     

Conceptual basis for regional monitoring of climatoecological measurements

A discussion is presented of the scientific, technological, and instrumental aspects of regional monitoring of climatoecological measurements of the Earth's atmosphere. By way of an example we present the observed trends in measurements of the average annual temperature in Tomsk, the Siberian region, and Russia over a period of several decades, and also the trends in the amount of cloud cover and the overall ozone content in the territory of Russia. Institute of Optical Monitoring, Siberian Branch of the Russian Academy of Sciences, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 61–70, September, 1998.     

Static multipole polarizability of atoms and ions in the Thomas-Fermi model

A method based on the Thomas-Fermi model for the electrostatic potential is proposed to calculate the multipole polarizabilities α _K of atoms and ions. In the case of highly charged ions an equation having a simple analytical form is derived. The dipole α₁ and quadrupole α₂ polarizabilities of atoms and ions with more than half-filled electron shells are calculated. Translated from Trudy Fizicheskogo Instituta im. P. N. Lebedeva, Lebedev Physics Institute, Russian Academy of Sciences, Moscow, Vol. 195, pp. 179–194, 1989.     

Experimental equation of state of the shape memory alloy Ti50Ni48Fe2 AT 0-8 GPa and 298 K

The influence of hydrostatic pressures (up to 8 GPa) at 298 K on the pressure curves of the volume and volume elastic modulus of the B2 phase of Ti₅₀Ni₄₈Fe₂ single crystals is investigated by an ultrasonic pulse-phase technique. It is proposed on analysis of the results that the alloy undergoes a B2→R martensitic, transition at 4.0–5.4 GPa. It is shown that the universal equation of state accurately describes the pressure dependence of volume over the entire pressure range. Institute of Strength Physics and Materials Science, Siberian Division, Russian Academy of Sciences. Institute of High-Pressure Physics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 48–53, August, 1997.     

Resonance laser actions as an efficient method for control of the gas and plasma states

The results obtained by the authors in studies of the mechanical action of resonance laser light on gas and plasma are briefly reviewed. L. V. Kirenskii Institute of Physics of the Siberian Branch of the Russian Academy of Sciences; Institute of Computational Modeling of the Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 96–105, August, 1999.     

Gas-filled position-sensitive detectors of thermal neutrons at the Konstantinov Petersburg Nuclear Physics Institute of the Russian Academy of Sciences

The manufacturing line for the development and fabrication of position-sensitive detectors of thermal neutrons has been organized at the Petersburg Nuclear Physics Institute of the Russian Academy of Sciences. Three detectors with sensitive regions 300 × 170 (prototype), 200 × 200, and 300 × 300 mm in size have been constructed to date. The detectors represent multiwire proportional chambers with cathode data readout to a delay line. The devices are filled with the ³He/CF₄ gas mixture. These detectors are intended for modernizing the detector systems of the Vector and Membrana-2 diffractometers (VVR-M reactor, Konstantinov Petersburg Nuclear Physics Institute of the Russian Academy of Sciences, Gatchina, Russia).     

Snow cover radiometry in the near millimeter wavelength range

The results of field and laboratory measurements of the thermal emission of the snow cover at wavelengths 1.3–0.87, 2.2, and 3.3 mm are presented. The potential of this wavelength range for sounding the boundaries and top layer condition of the snow cover, including the melting state, is analyzed and the results of the sounding are reported. Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 9, pp. 1113–1125, September, 1997.     

Powerful pulsed electrophysical transformers from the Institute of High-Current Electronics,Siberian Branch of the Russian Academy of Sciences

Problems in the creation and exploitation of powerful pulsed electrophysical transformers, developed at the Institute of High-Current Electronics, Siberian Branch of the Russian Academy of Sciences, are discussed. The power of the largest installations is 2.5·10¹² W (pulsed). The small size, the outside location of the main components requiring maintenance, and the absence of large volumes of transformer oil make the pulsed transformers competitive with pulsed voltage generators. Institute of High-Current Electronics, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 58–66, December, 1995.     

Powerful pulsed source of seismic oscillations

A source of seismic oscillations for surface and borehole seismic prospecting is described. The source was developed at the Institute of High-Current Electronics Siberian Branch, Russian Academy of Sciences. The results of preliminary field tests are reported, and the prospects for further improvement are discussed. Deceased Institute of High-Current Electronics, Siberian Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 100–104, December, 1997.     

The role of excited species in UV-laser materials ablation

UV-laser ablation is described in terms of a two-level system in which the excitation energy is dissipated via stimulated emission, thermal relaxation, and activated desorption of excited species. For thermal relaxation times t _T>10^–9 s and E* E (activation energies for excited-state and ground-state species) the model predicts high ablation rates at moderate surface temperatures, typically below 2000° C.On leave from General Physics Institute, Russian Academy of Sciences, 117942 Moscow, RussiaOn leave from Institute of Applied Physics, Russian Academy of Sciences, 603600 Nizhnii Novgorod, RussiaOn leave from L.D. Landau Theoretical Physics Institute, Russian Academy of Sciences, 142432 Chernogolovka, Moscow region, Russia     

Laser separation of rare isotopes in industrial-scale quantities

The series of investigations into laser isotope separation by the atomic vapor laser isotope separation (AVLIS) method, carried out at the Institute of General Physics of the Russian Academy of Sciences and the Scientific-Production Firm LAD in the last 4–5 years, is discussed. Basic physical problems solved in the development of facilities capable of producting high-enrichment¹⁶⁸Yb on an industrial scale are pointed out. Some units of the facility are briefly described, on which the following¹⁶⁸Yb concentrations are achieved: 90–95% in plasma, up to 62% on the collector, and up to 45% in wastes. The production rate of enriched ytterbium reaches 5–10 mg/h (more than a gram per month). Institute of General Physics of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 82–87, August, 1999.     

Integrable chain of electrons coupled with squeezed phonons

The exact wave function for a one-dimensional chain of electrons coupled with squeezed phonons is obtained. The ground state energy and the gap in the electron spectrum are calculated. It is shown that there exists an optimal phonon number n ^ph≠0 for the ground state of the system. The results are generalized for a system of correlated electrons. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 3, 140–145 (10 August 1996) On leave from Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, 31 Leninskii prosp., GSP-1, Moscow, 117907, Russia Published in English in the original Russian journal. Edited by Steve Torstveit.     

High-power electron ring beams as x-ray sources for uniform irradiation of large-area objects

The paper substantiates the use of high-current megavolt diodes with a ring cathode and a high aspect ratio (R/d≫1) as radiation sources for irradiating objects with a large area (500–1000 cm²). The size of the irradiated area is shown to depend weakly on the nature of the angular dependence of the radiator for moderate energies (0.5–1.5 MeV) of accelerated electrons. Institute of Strong-Current Electronics, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 40–44, December, 1995.     

Microwave radiometry of the snow cover and frozen soil at a frequency of 3.95 GHZ

The influence of stratigraphy of the snow cover on its radio-brightness temperature in the centimeter interval of the microwave range is considered. It is shown that the observed angular distributions of radio-brightness temperature are related to the structural variations of the snow cover. The possibility of developing a method for remote monitoring of the internal layers of the snow cover is discussed for the purpose of predicting avalanche hazard in mountains. Institute of Space Research, Russian Academy of Sciences, Moscow, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 8, pp. 1050–1059, August, 1997.     

Features of evolution of the substructure in the creep of dispersion-hardened nickel

A study is made of the laws governing high-temperature creep and the evolution of the substructure in dispersion-hardened alloy Ni — 3 vol. % HfO₂ during its free annealing and creep. The polygonized substructure was formed in the alloy prior to annealing. An analysis is made of structural transformations at different structural levels and the mechanism of high-temperature creep in the alloy. Institute of the Physics of Strength and Materials Science, Siberian Branch of the Russian Academy of Sciences. All-Republic Engineering-Technical Center, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 83–89, March, 1998.     

Experiments with wire arrays at a submicrosecond current risetime

Experiments with wire arrays of the z-pinch geometry consisting of copper and tungsten wires of length up to 8 cm have been performed on the GIT-12 generator at a current pulse risetime of ∼300 ns and ∼1 μs. These modes were compared as to the efficiency of the wire array implosion. For the 300-ns pulse a ∼5-nH/cm change in inductance has been achieved. It has been demonstrated that the lifetime of the plasma precursor is proportional to the current risetime. Institute of High Current Electronics, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 81–90, December, 1999.     

High-power Čerenkov microwave oscillators utilizing High-Current nanosecond Electron beams

A short review is given of results obtained at the Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences on generating high-power microwave radiation. Most of the research was devoted to a study of stimulated Čerenkov radiation from relativistic electron beams. It is shown that the efficiency of a relativistic 3-cm backward wave tube with a nonuniform coupling resistance can reach 35%. High-frequency radiation was discovered in the emission spectrum of the Čerenkov oscillators and it was shown that the nature of the radiation was associated with the stimulated scattering of low-frequency radiation by the relativistic electrons. Radiation with a power of 500 MW was obtained in the 8-mm wavelength range using a two-beam Čerenkov oscillator. High-current pulse-periodic nanosecond accelerators with a charging device utilizing a Tesla transformer were used in the experiments. The possibility was demonstrated of generating high-power microwave radiation with a pulse-repetition frequency of up to 100 Hz. An average power of ∼500 W was achieved from the relativistic oscillators. A relativistic backward wave tube with a high-current electron beam was used to make a prototype nanosecond radar device. Some of the results presented were obtained jointly with the Russian Academy of Sciences Institute of Applied Physics. Questions concerning multiwave Čerenkov interaction are not considered in this paper. Institute of High-Current Electronics, Siberian Branch of the Russian Academy of Sciences, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 5–20, December, 1996.