Surface processes in hydrogen permeation through metal membranes

The phenomenon of hydrogen permeation through metals is considered as a complex of interphase and diffusion processes. Basic principles of application of the hydrogen permeation technique to studies of various stages of hydrogen interaction with metals are formulated. An analysis is made of possible errors of the permeation technique when used to measure the characteristics of hydrogen diffusion through metals originating from the finite rate of the interphase processes. The permeation of nonequilibrium and corrosion-produced hydrogen through metal membranes, and the hydrogen permeability of multilayer systems are considered.     

Cluster of scintillation counters for the shower array in the NEVOD EAS project

A shower array for investigations of primary cosmic rays in the knee region in the energy spectrum of extensive air showers is being designed on the basis of the NEVOD experimental complex. Features of the cluster organization of the array and the results of the study of the characteristics of both the basic scintillation counter and the counter cluster, which is the basic element for triggering, detecting, and data collection and treatment systems, are discussed.     

Muon calibration of the cherenkov water detector NEVOD

The problem of calibrating a Cherenkov water detector (CWD) and the possibilities for its use based on the example of the CWD NEVOD are discussed. Results of the calibration of quasi-spherical modules in water volume by means of vertical muons selected by scintillation telescopes and compared to the results from measurements performed at test facilities are presented.     

Energy spectrum of cascade showers generated in water by near-horizontal muons

We discuss measuring cascade shower energy using the NEVOD Cherenkov water detector with a spatial lattice of quasi-spherical modules (QSMs). Dense QSM spacing makes it possible to reconstruct a number of cascade particles along the shower axis from the PMT response amplitude. Our cascade curve reconstruction technique is applied to showers generated by near-horizontal high-energy muons selected using the DECOR coordinate detector deployed around NEVOD. The first results from cascade energy spectrum measurements are reported.     

Detection of GLE of December 13, 2006, using the muon hodoscope

GLE of December 13, 2006, is analyzed based on the data of the muon hodoscope located at MEPhI (Moscow). The setup supermodules registered that the muon flux intensity started increasing at 0254 UTC. An increase at a maximum (0300 UTC) was 0.61 ± 0.09% (for the 10-min data), which is larger than six standard deviations. The detection of the muon flux in the hodoscope mode for the first time made it possible to obtain the two-dimensional images of an increase in the muon flux. A comparison of the muon hodoscope and neutron monitor data makes it possible to conclude that the muon event was caused by a highly collimated bunch of the solar proton fast component.     

Cascade showers in the NEVOD Cherenkov water detector

A technique for measuring the cascade shower energy in the NEVOD Cherenkov water detector with a spatial lattice of quasi-spherical modules is discussed. The technique allows the number of cascade particles that move near the shower axis to be reconstructed on the basis of analysis of response amplitudes of triggered photomultiplier tubes. The technique of cascade-curve reconstruction was applied to cascade showers generated by near-horizontal high-energy muons extracted by means of the DECOR coordinate-tracking detector arranged around the Cherenkov water detector. The first results of measuring the energy spectrum of cascade showers of 10–1000 GeV are presented.     

Interaction of graphite with atomic hydrogen

The kinetics of sorption of atomic hydrogen by pyrolytic, quasi-single-crystal, and RGT commercial-grade graphite was studied. The processes of sorption and subsequent thermal outgassing are shown to proceed in a similar manner for all the three types of graphite. Thermal desorption spectra obtained during linear heating of hydrogen-saturated samples have two peaks. A mathematical model including features of the thermal desorption kinetics that are observed when heating is terminated is suggested. According to this model, two types of traps with binding energies of 2.4 and 4.1 eV are present in graphite. The physical justification of the model is given.     

Profiling of energy deposition fields in a modular HTHR with annular core: Computational/experimental studies at the ASTRA critical facility

The paper presents the results obtained from the computational/experimental studies of the spatial distribution of the ²³⁵U fission reaction rate in a critical assembly with an annular core and poison profiling elements inserted into the inner graphite reflector. The computational analysis was carried out with the codes intended for design computation of an HTHR-type reactor.     

NEVOD–DECOR Experiment on the Measurement of the Energy Deposit of Cosmic Ray Muon Bundles

Physics of Atomic Nuclei - In comparison with calculations, the excess of multimuon events found in many experiments at ultrahigh energies of extensive air showers (EASs) cannot be explained using...     

Representation of Renormalization Group Functions By Nonsingular Integrals in a Model of the Critical Dynamics of Ferromagnets: The Fourth Order of The ε-Expansion

Using the representation for renormalization group functions in terms of nonsingular integrals, we calculate the dynamical critical exponents in the model of critical dynamics of ferromagnets in the fourth order of the ε-expansion. We calculate the Feynman diagrams using the sector decomposition technique generalized to critical dynamics problems.