Muon diagnostics of the Earth’s atmosphere and magnetosphere

A method of distant monitoring of the Earth’s magnetosphere and atmosphere is described, which is based on the close correlation between the modulations in the flux of atmospheric muons detected at the Earth’s surface and the dynamic processes in the Earth’s magnetosphere and atmosphere and implies the use of large-area muon hodoscopes with high angular accuracy of muon detection. The results of the analysis of the experimental data obtained on the muon hodoscopes used at the Moscow Engineering Physics Institute show that muon detection at the Earth’s surface in the hodoscopic mode gives a qualitatively new information about the main sources of muon flux modulation.     

Muon Tomography of Large-Scale Objects

Physics of Atomic Nuclei - Cosmic ray muons arriving from the upper hemisphere to the Earth’s surface, are currently used to develop methods of muonography (analogous to radiography) of the...     

Principle of maximal randomness and parity violation in turbulence

We show that in the self-consistent equations for equal-time correlation functions of velocity fluctuations obtained in the model of developed turbulence based on the maximal randomness principle, infrared divergences are absent from all orders of the perturbation theory. We analyze the additional ultraviolet (UV) divergences that appear in the two-loop approximation of the self-consistent equations. We show that in the system with conserved parity, these divergences can be eliminated using the existing ambiguity in the solution. In the case of parity violation in the system, the UV divergences have a logarithmic form, which can indicate a deviation from the Kolmogorov scaling.     

Wide-aperture muon detector for diagnostics of the Earth’s atmosphere and magnetosphere

A wide-aperture large-area multilayered muon hodoscope is being constructed above the water Cherenkov calorimeter NEVOD (Moscow Engineering Physics Institute). This hodoscope is aimed at studying the processes in the Earth’s atmosphere and magnetosphere that lead to variations in the muon flux at the ground level. The structure of the detector and its data acquisition and triggering systems are described. Some preliminary results of the analysis of the data obtained using the first two supermodules of the system in the continuous series of measurements during 2005–2006 are discussed.     

Delocalization of Longitudinal Acoustic-Like Excitations in DNA Due to Structural Effects

Terahertz-frequency phonon-like modes in DNA have been widely studied both experimentally and theoretically in recent years. However, current theoretical models turn out to fail to reproduce some basic properties of these modes. Using a generalized hydrodynamics approach and the results of inelastic X-ray scattering measurements, we propose a model to describe structural effects due to wavenumber dependence of the static structure factor in the dynamics of longitudinal acoustic-like excitations in DNA. Our analysis qualitatively suggests that on a length scale corresponding to a wavenumber region between the positions of the maximum and the minimum of the dispersion relation for the excitation frequency, structural effects may induce a tendency of delocalization of the dynamics. This proposal is consistent with the recent experimental observations of delocalized terahertz-frequency DNA phonon-like modes that seem to be relevant to biological function.

     

Measurements of integrated muon intensity at large zenith angles

Data from the DECOR coordinate detector on the integrated intensity of muons that have a threshold energy of 1.2 to 2 GeV are analyzed over the zenith-angle interval 60°–90°. Experimental results in these intervals of zenith angles and threshold energies were obtained for the first time. In the interval θ ≤ 80°, the integrated intensity at E _min = 1.5 GeV as a function of the cosine of the zenith angle is described by a power-law function characterized by an exponent value of n = 1.884 ± 0.005, which is close to the value obtained in earlier experiments.     

Representation of the β-function and anomalous dimensions by nonsingular integrals: Proof of the main relation

A method for calculating the β-function and anomalous dimensions, convenient for numerical calculations in the ?-expansion framework, was previously proposed, and the relation underlying the method was verified up to the four-loop approximation. We prove this relation in all orders of the perturbation theory.     

Evaluated benchmark experiments at critical assemblies simulating features of an HTHR at the ASTRA facility

The design of the ASTRA facility and critical assemblies that simulate physics features of modular high-temperature reactors (HTHR-Ms) with a graphite moderator and reflectors loaded with fuel particles having multilayer ceramic coatings is described in detail. Geometrical dimensions of the main elements and regions of the critical assemblies, composition of the materials used, and experimental results for various configurations of the critical assemblies are presented. A detailed computational benchmark model allowing for the structural and compositional features of the critical assembly configurations in question is developed on the basis of all the above data. The results are to be used for verification of the neutronics codes used for calculations of high-temperature helium-cooled reactors.     

HYDRA hydroacoustic antenna in the NEVOD experimental complex

The main characteristics of the HYDRA hydroacoustic antenna intended for the detection of signals generated by cores of extensive air showers in a water Cherenkov detector involved in the NEVOD experimental complex are considered. Primary attention is focused on the calibration of antenna sensors and on the selection of an optimum trigger that ensures an effective detection of acoustic signals generated by cores of extensive air showers in the water volume of the Cherenkov detector.