Determination of the absorption coefficient of solids in the short-wave region of the millimeter band

A technique for measuring the absorption coefficient of solids in the short-wave region of the millimeter band is described. The absorption coefficients of six materials were measured at a wavelength = 2mm.The authors express their gratitude for the interest of Academician A. M. Prokhorov, in whose laboratory this work was done. The authors also wish to thank E. A. Vinogradov for his assistance.     

Diagrammatic method for the calculation of short-range order effects in an ordering binary alloy

A statistical thermodynamic theory of short-range order effects in an ordering binary alloy with an arbitrary composition and an arbitrary radius of the interatomic interaction has been constructed in the approximation of ring diagrams for the free energy. For concreteness, a solid solution, which orders according to the Cu₃Au type, has been considered. A formula has been obtained for the Fourier components of the correlation parameters, which is valid for a wide range of variation of concentration and temperature of the alloy. Correlation parameters of the system Cu₃Au with a stoichiometric composition have been calculated according to this formula for given values of the displacement energy for various coordination spheres at several values of temperature and the interaction radius.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 62–67, August, 1988.The authors thank D. M. Sedrakyan and É. M. Kazaryan for a discussion of the results.     

Reconstruction of the scattering potential from the high-energy differential cross section

A simple equation is derived for use in reconstructing the scattering potential from the angular distribution of scattered particles at a given energy. This equation is useful in the classical approximation of small angles and in the semiclassical quantum-mechanical treatment. Experimental data and this equation are used to reconstruct the interaction potentials for the scattering of helium, neon, and argon ions by atoms from the same group in various combinations, at 25, 50, and 100 keV. The simplicity of the equation allows potentials to be found at distances larger than were found previously by Everhart and Lane and with a smaller error in the approximate numerical calculations.Translated from Izvestiya VUZ. Fizika, No. 8, pp. 118–123, August, 1970.The authors thank O. M. Tsoi for assistance in the numerical calculations.     

Radiation of an electron in the quantum field of a nonmonochromatic electromagnetic wave

This study considers the radiation of an electron upon its interaction with one photon and a vacuum of all remaining photons of a quantum plane nonmonochromatic electromagnetic wave. Consideration of the vacuum of an infinite number of photons leads to a change in the spectrum and differential probability of radiation. In the case of a low-intensity plane wave the corresponding finite corrections are calculated, reflecting the role of the vacuum in the process under consideration.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 120–127, July, 1978.The authors thank V. G. Bagrov and D. M. Gitman for their valuable advice on the questions considered in this study.     

Quantum numbers for the problem of two coulomb centers

A complete set of commuting operators and the corresponding complete set of quantum numbers are found for the motion of an electron in the field of two Coulomb centers. The symmetry group of the H ₂ ⁺ ion is found.Translated from Izvestiya VUZ. Fizika, Vol. 11, No. 8, pp. 23–27, August, 1968.In conclusion, the authors thank Ya. A. Smorodinskii for useful discussions.     

On the transformation of the stokes parameters for backscattering of electromagnetic waves

Expressions are derived for the interaction matrices which describe the transformation of the Stokes parameters for backscattering of a plane quasimonochromatic electromagnetic wave by an arbitrary statistical object or by an isotropic object. By means of the matrices that have been found the determination of the mutual correlation of the orthogonal components of the scattered field must be considered in an arbitrarily chosen polarization basis for arbitrary elliptic polarization of the incident wave. For the isotropic object the modulus and argument of the generalized correlation coefficient of the linear orthogonal components of the scattered field are obtained.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 15, No. 4, pp. 601–610, April, 1972.The authors thank E. M. Kuchkov for his unfailing attention to the work.     

π-Meson scattering on nucleons. II

The interaction constants are determined for the interaction of-mesons and nucleons described by anomalous equations. The experimental data on-meson scattering on nucleons and the data obtained when studying the shell structure of the atomic nucleus are used. The magnitude of the values found for the interaction constants is acceptable.The authors thank M. Plchová for carefully carrying out the series of numerical calculations.     

Radiation of a scalar particle in the field of two oppositely directed electromagnetic travelling waves

The radiation of a charged spinless particle in a field of two linearly polarized, oppositely directed electromagnetic travelling waves is treated in the small-field approximation. Equations are derived for the radiation probability, and the polarization properties of the radiation are studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, Vol. 12, No. 1, pp. 69–73, January, 1969.The authors thank Professor I. M. Ternov for interest in this study and useful discussions.     

Calculation of the trapping parameters from combined measurements of thermostimulated currents and the thermodepolarization of the photoelectret state

The Garlick and Gibson model for a combined examination of thermostimulated currents in normal and photoelectret regimes is developed in this paper. A method is proposed for calculating the combination of parameters characterizing a trap (activation energy, concentration, degree of filling, frequency factor, and so on). A monogram was calculated to give rapid evaluation of the degree of filling of the traps. The proposed methods are applied to single crystals of lead oxide.Translated from Izvestiya Vysshikh Uchebnykh Zavedeni, Fizika, No. 10, pp. 29–33, October 1974.The authors would like to thank V. M. Lyubin for some useful discussions and very valuable comments, and A. E. Gel'man and B. S. Medved' for carrying out the computer calculations.     

Simultaneous np and pp phase shift analysis at 18.2 and 9.9 mev and the question of additivity of Coulomb and nuclear phase shift

The simultaneous phase-shift analysis of np and pp data is performed at 18.2 and 9.7 MeV. Three and four sets of phase-shifts are obtained, respectively. The previously obtained nuclear potentials for non-mixing states of the two-nucleon system are used to calculate the maximum error in the simultaneous phase-shift analysis, due to the assumption on the additivity of the Coulomb and nuclear phase-shifts. Optimal experiments are planned for a further specification of the experimental quantities.In conclusion the authors thank J. Bystrický, L. I. Lapidus, R. M. Ryndin and P. Winternitz for helpful discussions and E. Dudova, J. Fingerova, A. M. Fokina and L. F. Graczeva for their assistance.     

Quenching of the spin-dependent scattering of weakly interacting massive particles on heavy nuclei

We present calculations of the quenching of the spin-dependent elastic scattering cross section for dark matter WIMPs on heavy nuclei. The theory of finite Fermi systems was used to describe the behavior of the nuclear spin matrix elements in the nuclear medium. The results of the calculations for planned dark matter detector nuclei are not only always smaller than corresponding single particle estimations but in some cases also differ from the ones obtained by using measured nuclear magnetic moments.One of the authors (M.A.N.) wants to thank the Max-Planck-Institut für Kernphysik (Heidelberg, Germany) for the hospitality during the time in which this work was carried out, and the Deutscher Akademischer Austauschdienst (DAAD) for financial support.     

The measurement of the local electron density by means of direct reading microwave interferometer

The present paper describes a microwave X-band interferometer in which a Lecher-wire system has been applied. The interferometer is suitable for dynamic and local measurements of the electron density in plasma. The sensitivity of the interferometer for 50 mm path of microwaves in plasma is about 4×10⁹ cm^–3. The spatial resolutions in two directions perpendicular to the Lecher line axis is about 10 mm and 5 mm.One of the authors of the present paper, M. ícha, wishes to thank for the support obtained from Polish Academy of Sciences during the course of this work. The authors would like to thank Mr. K. Wykretowicz for his help in preparing the experimental apparatus.     

On the use of large pixel PIN diode array in plasma diagnostics

Silicon PIN diodes tailored for x-ray diagnostics of high-temperature plasmas were investigated. Their spectral responsivity was determined from the direct calibration of the diodes by x-rays and indirectly through the bombardment by monoenergetic electrons, the accuracy of the calibration amounts to 11.5 %. The single diodes are used in combination with an absorption foil technique, the large pixel PIN diode array was utilized in a compact spectrometer for monitoring the electron temperature and density of laser produced plasma. The construction of the spectrometer and an example of experimental results are presented.The authors would like to thank M. Chvojka, B. Kralíková, K. Maek, J. Skála and other scientists from the staff of laser system Perun for the assistance in interaction experiments and E. Tegeler and M. Krumrey of the Radiometric Laboratory of the Physikalisch-Technische Bundesanstalt at the electron storage ring BESSY for measuring the diode responsivity in VUV spectral region.     

M1-transitions and the mutual orientation of the unpaired nucleons in odd-odd nuclei

Experimental lifetimes and branching ratiosB(M1)/B(E2) are used to determine reduced M1-transition probabilities between collective-band levels withI=1 in^{102, 104, 106}Ag and in the odd-odd isotopes of La, Pr, Pm and Tl. The extractedB(M1) values are compared with calculations in the framework of the quasiclassical approximation and the model axial rotor+two quasiparticles. The reduced M1-transition probabilities along with the magnetic moments were found to depend on the mutual orientation of the angular momenta of the unpaired nucleons in the odd-odd nuclei.The authors would like to thank the staffs of Cyclotron Laboratory of P.T.I. in St. Petersburg and the Nuclear Moments Laboratory of I.N.R. in Kiev for assistance in the experiments. One of us (A.I.L.) wishes to thank the Sektion Physik of the Ludwig Maximilians Universität München for its hospitality and financial support.     

Focusing and decreasing the effective emittance of hollow charge particle beams by octupole magnetic lenses

A possibility to focus a (hollow) charged particle ring beam and to decrease the effective emittance by the octupole magnetic lenses is shown. The particle dynamics was studied in the case of collective accelerator (KUTI-20) ion beam. The calculation confirmed the fitness of octupole lenses in the hollow beam optics.The authors thank prof. V. P. Sarantsev and dr. A. D. Dymnikov for valuable discussions.     

XeI and XeII radiative lifetimes and transition probabilities

The lifetimes of ten levels of the xenon atom and two levels of the ion were measured. The probabilities for several transitions are calculated. The effective decay cross section is calculated for collisions for the 2p₈ level of the xenon atom.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 3, pp.24–29, March, 1971.The authors thank V. S. Mel'chenko for assistance in this study.     

Localizability of massless particles in the framework of the conformal group

Localizability of massless particles in the framework of the conformal group is given by means of imprimitivity systems for particular representations of the Sitter groupSO ₀(4, 1).Dedicated to Professor Ivan Úlehla on the ocassion of his sixtieth birthday.The authors wish to thank Professors M. Flato and W. Schmid for stimulating discussions.     

Intermittency in the Fisher's droplet model

Intermittent behaviour of fragment multiplicity distributions in the nuclear liquid-gas phase transition is studied in terms of the droplet model of Fisher. The anomalous fractal dimensions are compared with data on heavy ion reactions and classical molecular dynamics simulations. A signature of the transition in the anomalous fractal dimensions is shown.We thank Profs. S. Ayik, M. Di Toro and V. Kondratyev for discussions. One of us (T.K.) acknowledges the support of INFN-LNS.     

A poblem of forced diffusion in a region with a moving boundary

A solution is found for a boundary problem of the equation of forced diffusion in a semi-infinite region with a moving boundary, with the dependence of the mass-exchange coefficient taken into account. The solution is obtained in the form of series of the Liebnitz type, which makes it convenient for numerical calculations.The authors wish to thank Professor G. M. Bartenev for his interest in this work and discussion of the results.     

Approximate calculation of the effective cross section and optical characteristics of dyes in the region of the electronic absorption bands

An approximate method is described for calculating the effective cross section for light absorption by dye molecules and for calculating the absorptance on the basis of experimental data.Translated from Izvestiya VUZ. Fizika, No. 12, pp. 113–120, December, 1969.The authors thank V. M. Korovina for furnishing the experimental data used in these calculations.