Boron Isotopes in the PAMELA Experiment

Analysis of the isotope composition of nuclei in galactic cosmic rays (GCR) in the PAMELA orbital international experiment allows studying the problems of cosmic-ray origin and propagation in our Galaxy. PAMELA magnetic spectrometer data provided the significant progress in the study of the light nuclei isotope composition of GCR from H to Be in the energy range ∼0.1–1 GeV/nucleon. This makes it possible to estimate the contribution of local (∼100 pc) young (∼10⁶ years) interstellar sources (LISS) into GCR fluxes from supernova explosions. The analysis of boron (B) isotope fluxes in the GCR has so far been carried out only in the energy range ∼0.08–0.17 GeV/nucleon in the space experiments Voyager, Ulysses, ACE. In the present contribution the attempt was done to determine the ¹¹B/¹⁰B ratio in the energy range ∼0.1–1.0 GeV/nucleon for the first time on the base of 2006–2014 PAMELA data using the measurements of the detected nuclei rigidities, velocities and ionization losses in a multilayer calorimeter. The new PAMELA results are consistent with existing as experimental data and those expected from simulations. However the statistical and systematic measurement uncertainties do not allow to separate the local boron source contributions into GCR fluxes. The preliminary results of the boron isotope flux analysis in GCR (¹⁰B, ¹¹B spectra and ¹¹B/¹⁰B ratio dependences on the rigidity and energy) are presented as well as the existing measurement data and simulation results.

     

Laser Fabrication and Fragmentation of Selenium Nanoparticles in Aqueous Media

Physics of Wave Phenomena - The formation of selenium nanoparticles by laser ablation of its target in pure water and water containing biocompatible surfactants has been experimentally...     

Solar modulation of cosmic deuteron fluxes in the PAMELA experiment

The preliminary results from measurements of deuteron fluxes in galactic cosmic rays (GCR) in the vicinity of the Earth in 2006–2009 are presented. The results are obtained by analyzing data from the PAMELA experiment aboard the Resurs DK-1 satellite. High-precision detection instruments provided an opportunity to identify GCR deuterons and measure their spectrum in the energy interval of 90–650MeV/nucleon. Spectra averaged over six-month intervals from the summer of 2006 to the summer of 2009 (the solar activity minimum) are presented. The influence of solar modulation on the observed spectrum is clearly seen in the results.     

Effects of 2 particle–2 hole configurations on dipole states in neutron-rich <Emphasis Type="Italic">N</Emphasis> = 80–84 isotones

Starting from the Skyrme interaction SLy4 we study the effects of 2 particle–2 hole configurations on the low-energy electric dipole response in ^130–134Sn. It is shown that the pygmy dipole resonance properties are correlated with the neutron skin thickness. The two-phonon configurations give a considerable contribution to the low-lying E1 strength.     

Description of low-lying state structures with Skyrme interaction

We use the quasiparticle random phase approximation to study properties of the low-lying 2⁺ states in the even-even nuclei around ¹³²Sn. Starting from a Skyrme interaction in the particle-hole channel and a density-dependent zero-range interaction in the particle-particle channel, the calculation within the finite-rank separable approximation for the residual interaction is performed.     

Observation of solar-magnetospheric and geophysical effects on the electron and proton fluxes detected by the satellite-borne ARINA instrument

New results are presented on the observations of bursts and variations in high-energy charged-particle fluxes in the near-Earth space by the ARINA instrument operated onboard the Resurs-DK1 satellite since 2006.     

Structures of distorted phases and critical and noncritical atomic displacements of elpasolite Rb<Subscript>2</Subscript>KInF<Subscript>6</Subscript> during phase transitions

The structures of all three phases of the Rb₂KInF₆ crystal have been determined from the experimental X-ray diffraction data for the powder sample. The refinement of the profile and structural parameters has been carried out by the technique implemented in the DDM program, which minimizes the differences between the derivatives of the calculated and measured X-ray intensities over the entire profile of the X-ray diffraction pattern. The results obtained have been discussed using the group-theoretical analysis of the complete order-parameter condensate, which takes into account the critical and noncritical atomic displacements and permits the interpretation of the experimental data obtained previously. It has been reliably established that the sequence of changes in the symmetry during phase transitions in Rb₂KInF₆ can be represented as $ Fm\bar 3m\xrightarrow[{0,0,\phi }]{{11 - 9\left( {\Gamma _4^ + } \right)}}{{I114} \mathord{\left/ {\vphantom {{I114} {m\xrightarrow[{\left( {\psi ,\phi ,\phi } \right)}]{{11 - 9\left( {\Gamma _4^ + } \right) \oplus 10 - 3\left( {X_3^ + } \right)}}{{P12_1 } \mathord{\left/ {\vphantom {{P12_1 } {n1}}} \right. \kern-\nulldelimiterspace} {n1}}}}} \right. \kern-\nulldelimiterspace} {m\xrightarrow[{\left( {\psi ,\phi ,\phi } \right)}]{{11 - 9\left( {\Gamma _4^ + } \right) \oplus 10 - 3\left( {X_3^ + } \right)}}{{P12_1 } \mathord{\left/ {\vphantom {{P12_1 } {n1}}} \right. \kern-\nulldelimiterspace} {n1}}}} $ Fm\bar 3m\xrightarrow[{0,0,\phi }]{{11 - 9\left( {\Gamma _4^ + } \right)}}{{I114} \mathord{\left/ {\vphantom {{I114} {m\xrightarrow[{\left( {\psi ,\phi ,\phi } \right)}]{{11 - 9\left( {\Gamma _4^ + } \right) \oplus 10 - 3\left( {X_3^ + } \right)}}{{P12_1 } \mathord{\left/ {\vphantom {{P12_1 } {n1}}} \right. \kern-\nulldelimiterspace} {n1}}}}} \right. \kern-\nulldelimiterspace} {m\xrightarrow[{\left( {\psi ,\phi ,\phi } \right)}]{{11 - 9\left( {\Gamma _4^ + } \right) \oplus 10 - 3\left( {X_3^ + } \right)}}{{P12_1 } \mathord{\left/ {\vphantom {{P12_1 } {n1}}} \right. \kern-\nulldelimiterspace} {n1}}}} .     

Trapped Positrons and Electrons in the Inner Radiation Belt According to Data of the PAMELA Experiment

Measurements of secondary-electron and secondary-positron fluxes below the geomagnetic cutoff in near-Earth space were performed by means of the PAMELA magnetic spectrometer installed on board the Resurs-DK1 satellite launched on June 15, 2006, in an elliptical orbit of inclination 70° and altitude 350 to 600 km. This spectrometer permits measuring the fluxes of electrons and positrons over a wide energy range, as well as determining their spatial distributions to a precision of about 2°. A calculation of particle trajectories in the geomagnetic field makes it possible to separate electrons and positrons originating from cosmic-ray interactions in the Earth’s magnetosphere. The spatial distributions of quasitrapped, trapped, and short-lived albedo positrons and electrons of energy above 70 MeV in the radiation belt were analyzed. The ratio of the electron-to-positron fluxes and the energy spectra of the electrons and positrons in question are indicative of different productionmechanisms for stably trapped and quasitrapped secondary particles.     

Second Harmonic Generation in Thin Zinc Sulfide Films

Optical second harmonic generation, mechanical stresses, and structure are investigated in thin polycrystalline zinc sulfide films. The resulting data indicate that there is no correlation between the mechanical stresses and the quadratic optical nonlinearity. In view of the X-ray diffraction results, the nature of the nonlinearity is explained using the model of a nanotextured film consisting of crystallites with the sphalerite or wurtzite structure. It is shown that this model allows satisfactory agreement between calculations and experiment.     

Formation of Polymer Nanolayers with Special Properties at Polymer Surfaces

A principal possibility of the utilization of polymer peroxides for the modification of polymer surfaces that provides an immobilization of the tailored quantity of peroxide groups at them has been established. The processes of polymer surface activation with following “grafting from” or “grafting to” utilizing immobilized peroxide groups has been studied using a FTIR-ATR spectroscopy, ellipsometry and measurements of contact angles. The proposed technique of polymer surface activation is based on the universal ability of carbon chain polymer to participate the free radical reactions.