Bulletin of the Lebedev Physics Institute最新文献

The paper presents a method that allows full-fledged resource-intensive 3D PIC simulation of the interaction of laser radiation with a large volume of cluster/droplet medium to be reduced to a series of simpler calculations by partitioning the interaction region into small zones. It is shown how normalization of the resulting spectra of accelerated ions can to used to dramatically decrease the number of necessary calculations by interpolating the obtained data.

Based on numerical simulation within the finite element method, a hybrid midwave IR photodetector is designed, in which incident electromagnetic radiation is converted into localized surface plasmons that act as an intermediary for excitation transfer to the semiconductor part of the detector. The near-field of surface plasmons allows to utilize thin InAsSb absorption layers to suppress the diffusion component of dark current and its associated noise and to increase quantum efficiency. The developed design taking into account manufacturing considerations is adapted to produce IR detectors that permit matrix format and have high detectivity at temperatures accessible for cascade Peltier elements.

Using spreading resistance microscopy (SRM) under atmospheric conditions, we demonstrate a stable contrast of the electrical properties on the cleaved cross-section of an undoped InAs/GaSb type-II superlattice with a period of 7.5 nm. It is shown that this contrast is a consequence of the difference in the conductivity of the InAs and GaSb layers of the superlattice. A simple and effective method is proposed for monitoring the structure and electron‒hole subsystem of InAs/GaSb superlattices used in modern IR photodetectors.

The νGeN experimental setup, with a low-threshold germanium spectrometer as its basic element, is deployed at Unit 3 of the Kalinin Nuclear Power Plant, at a distance of 11 m from the centre of the reactor core. The experiment aims to observe coherent elastic scattering of neutrinos off germanium nuclei, as well as to search for antineutrino electromagnetic properties. This paper presents an estimate of νGeN sensitivity to the antineutrino magnetic moment based on the 98 kg day reactor-OFF dataset. The expected limit is 5.3 × 10⁻¹¹ μ_B at the 90% confidence level for the exposition of 198 kg day with the reactor ON and 98 kg day with the reactor OFF. The projected sensitivity for the 1100 kg day reactor-ON dataset is 2.6 × 10⁻¹¹ μ_B.

We report our results on light absorption and scattering cross sections of composite spherical nanoparticles with a bimetallic core and an outer shell of molecular aggregates of cyanine dyes exhibiting two excitonic resonances. Calculations have been performed within the framework of the extended Mie theory by taking into account the frequency-dependent and size-dependent dielectric functions of gold and silver. It is shown that for such three-layer particles, a specific regime of strong plasmon-exciton coupling is achieved, when the induced transparency effect is manifested simultaneously at two different wavelengths. The spectral distance between two identified dips of induced transparency turns out to be 150 nm.

The results of experiments on measuring the magnetic field from the azimuthal component of the current during the explosion of thin wires in high-current generators are presented. The discharge was excited by high-voltage pulses of 20 kV, 500 ns, with current up to 8 kA. Laser, X-ray tenegrams from other similar experiments are given. An assumption is made that the appearance of strata in such discharges is caused by the appearance of the spiral component of the current in the discharge, which leads to the splitting of the plasma column of the discharge into strata under the action of the Ampere forces between the resulting current coils.

Electric currents arising in a nonlinear transmission line during the propagation of an electromagnetic KdV soliton are analyzed. An analytical expression for calculating the current soliton is obtained. It is shown that it has a classical profile, which in the approximation of small amplitudes is described by the soliton solution of the KdV equation. The voltage profiles between the ends of a section of one of the line conductors are also calculated; they are shown to have the form of symmetric bipolar pulses.

Probably, annihilation of atoms from magnetic monopoles (2.4 GeV) and their transitions in the Lyman series (1.8, 2.1, and 2.25 GeV) could result in a gamma-ray excess in our galactic center, which was observed by the Fermi observatory. Monopoles of GeV energies can form in the magnetospheres of magnetars and be blown out of them. At the galactic scale, atoms from magnetic monopoles (g⁺g^‒) are part of dark matter.

We propose a simple noncontact spectral method for determining the presence or absence of milk pasteurization. The method is based on the pasteurization temperature dependence of luminescence spectra of milk excited by ultraviolet radiation in the wavelength range of 300‒420 nm.

The experimental results of irradiation of the isotopically enriched [¹³⁵Ba]BaCO₃ targets by protons with an initial energy of 30 MeV are presented. The cross-sections of lanthanum and barium radioisotopes formed as a result of ¹³⁵Ba(p, x) nuclear reactions were measured and compared with theoretical data for the first time. The possibility of production of ¹³⁵La and ¹³³La for their further medical use was shown.