A database, including a map layer of ecosystems of the Lake Baikal basin, has been compiled at a scale of 1 : 500 000. The area is divided into 71 types of mesocombinations of plant communities and their anthropogenically transformed variants, which reflect natural units, corresponding to the level of urochishche/suburochishche of landscapes. A digital map layer of morphogenetic relief types (31 were specified) was elaborated to reflect the spatial variability of the distinguished geobotanical units. The map layer of the soil cover of the basin was based on interpolation of various published thematic data and supplemented by archived and long-term data of terrain survey of the soil cover performed by the Joint Russian–Mongolian Complex Biological Expedition of the Russian Academy of Sciences and of the Mongolian Academy of Sciences. The prepared database includes spatial data on ecosystems and their anthropogenic disturbance for nine model polygons (at a scale larger than 1 : 200 000) and eight test plots (at a scale of 1 : 5000–1 : 10 000), as well as 1757 geobotanical descriptions made by the authors earlier. The 5.1 GB spatial database is a cartographic web service located at https://mon-exp.nextgis.com/resource/ . It is intended for open use on any personal computer, workstation, notebook, tablet, and smartphone with Windows and Android OS, including mobile ones with Internet access.

The article outlines the main causes and effects of the destabilization of ecosystems in the Lake Baikal basin. They were identified via long-term monitoring based on large-scale mapping and landscape and soil-geobotanical studies on a network of model polygons and key sites established in areas with increased ecological tension. The degree of disturbance of the natural environment of the region is assessed, the main factors of degradation are revealed, and the pattern of degradation processes is determined in different types of terrestrial ecosystems in the Baikal basin.

A two-dimensional thermal-neutron detector developed for a small-angle diffractometer by the Petersburg Nuclear Physics Institute is described. The detector, with a sensitive area of 600 × 600 mm2, is based on a multiwire proportional chamber. A gas mixture containing 3He is the neutron converter. A new technology for manufacturing electrodes has been developed and used to increase both the gas purity and the lifetime of the detector without refilling its working volume under the experimental conditions. Data acquisition is carried out by the readout system based on the method of cathode-strip data readout to an LC delay line, which is located inside the detector. The detector is operable in a vacuum owing to its design.

The differential cross sections of the ( p, p ′) inelastic reaction on nuclei 12 C, 28 Si, 40 Ca, and 56 Fe at the initial proton energy of 1 GeV were measured over a wide range of the scattered proton momenta at a laboratory angle of Θ = 21°. Scattered protons were detected by means of the magnetic spectrometer equipped with a polarimeter based on multiwire proportional chambers. Momentum intervals were observed in which the ratios of the scattering cross sections off the nuclei do not depend on the scattered proton momentum (i.e., scaling).

The problem of finding and characterizing minimal sets of dequantizers and quantizers applied in the mapping of operators onto functions is considered, for finite-dimensional quantum systems. The general properties of such sets are determined. An explicit description of all the minimum self-dual sets of dequantizers and quantizers for a qubit system is derived.

The polarization of secondary protons in the (p, p’) inelastic reactions on 40Ca and 12C nuclei at the initial proton energy of 1 GeV was measured over a wide range of scattered-proton momenta at a laboratory angle of Θ = 21°. The reaction cross sections were also measured. Scattered protons were detected by means of magnetic spectrometer equipped with a polarimeter based on multiwire-proportional chambers. A structure in the polarization and cross-section data, which is probably related to scattering off nucleon correlations in the nuclei involved, was observed.

Multi-wire proportional chambers filled with the He + CF4 gas mixture with a delay line readout are widely used for thermal neutron detection, especially in Small-Angle Neutron Scattering (SANS) instruments [1–3]. The purpose of the discussed work was to find a set of strongly interrelated detector design parameters with the aim to improve the detector performance. After careful consideration of important detector parameters, such as the space resolution, the efficiency and differential and integral nonlinearity, a satisfactory solution was found. In order to guarantee a reliable and optimal operation of the neutron detector, a wide range of scientific and technological investigations was carried out to: • improve and optimize the detector mechanical characteristics, simulations of the detector pressure behavior up to 10 bar were performed; • minimize the detector outgassing, a new technology for fabrication of the detector electrodes was successfully developed. It has opened a way to improve the gas purity by a few orders of magnitude; • minimize the gas leakage to a level smaller than 0.03 % per day, the detector gas sealing technology was improved. This paper describes general approaches and technological solutions that have allowed us to develop thermal neutron detectors for the SANS diffractometers “Vector” and “Membrana-2” at the VVR-M reactor of PNPI. The required parameters of the detector are listed in Table 1.

The polarization of the secondary protons (P1,2) in the (p,2p) reaction with the S - shell protons of nuclei 4He, 6Li, 12C, 28Si, 40Ca was measured at 1 GeV unpolarized proton beam. The spin correlation parameters Cij for the 4He and 12C targets also were for the first time obtained. The polarization measurements were performed by means of a two - arm magnetic spectrometer each arm of which was equipped with multiwire - proportional chambers polarimeter.

The manufacturing line for the development and fabrication of position-sensitive detectors of thermal neutrons has been organized at the Petersburg Nuclear Physics Institute of the Russian Academy of Sciences. Three detectors with sensitive regions 300 × 170 (prototype), 200 × 200, and 300 × 300 mm in size have been constructed to date. The detectors represent multiwire proportional chambers with cathode data readout to a delay line. The devices are filled with the 3He/CF4 gas mixture. These detectors are intended for modernizing the detector systems of the Vector and Membrana-2 diffractometers (VVR-M reactor, Konstantinov Petersburg Nuclear Physics Institute of the Russian Academy of Sciences, Gatchina, Russia).

A two-dimensional thermal neutron detector for neutron diffraction experiments has been developed and designed at the St. Petersburg Nuclear Physics Institute, Russian Academy of Sciences. The detector is based on a multiwire proportional chamber with cathode-strip delay line readout. The detector aperture is 170 × 300 mm 2 and the anode wire spacing is 4 mm. The chamber is filled with a 1.5 atm 3 He + 2 atm CF 4 gas mixture. To conserve high purity of the gas mixture, all electrodes are made of quartz glass. The spatial resolution of the detector is 2.5 mm and the detection efficiency is 60% for 9 Å neutrons.

The rate of nuclear muon capture by the proton has been measured using a new technique based on a time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas, which is key to avoiding uncertainties from muonic molecule formation. The capture rate from the hyperfine singlet ground state of the microp atom was obtained from the difference between the micro(-) disappearance rate in hydrogen and the world average for the micro(+) decay rate, yielding Lambda(S)=725.0+/-17.4 s(-1), from which the induced pseudoscalar coupling of the nucleon, g(P)(q(2)=-0.88m(2)(micro))=7.3+/-1.1, is extracted.

The rate of nuclear muon capture by the proton has been measured using a new technique based on a time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas, which is key to avoiding uncertainties from muonic molecule formation.The capture rate from the hyperfine singlet ground state of the p atom was obtained from the difference between the ÿ disappearance rate in hydrogen and the world average for the decay rate, yielding S 725:0 17:4 s ÿ1 , from which the induced pseudoscalar coupling of the nucleon, g P q 2 ÿ0:88m 2 7:3 1:1, is extracted.

The polarization of protons emitted in (p,2p) reactions has been measured for three kinds of targets at 1 GeV. The values of the polarization that we obtain are significantly smaller than the values predicted using the nucleon-nucleon (NN) interaction in free space, and the discrepancy between the two is seen to increase monotonically as a function of the effective mean density, which is defined as a measure of the sensitivity of a reaction to density-dependent terms of the interaction. The experimental data are also compared with a model calculation that includes a relativistic effect, and it is found that inclusion of this effect is able to account for about half of the density-dependent discrepancy between the experimental results and the values predicted with the free space NN interaction. These results, in conjunction with the previous results at 392 MeV, indicate that this discrepancy is not caused by a contribution of multistep processes and provide further evidence that there exists a medium effect.

We have measured polarizations P of outgoing protons in (p, 2p) reactions at an incident energy of 1 GeV for three kinds of targets. The experimental result shows a distinct reduction from IA calculation values using NN interaction in free space and the reduction is found to be monotonic to the effective mean density estimated with DWIA. This is consistent with the previous result obtained at 392 MeV, though the incident energy is quite different. We have also measured an angular distribution of the polarization for C-12 target. All of the data, including both for forward nd backward outgoing protons, show similar reduction from the IA calculation, though, again, outgoing energies are quite different from 130 MeV to 890 MeV. From these results, it is concluded that these reductions are nuclear structure or interaction originated and not caused by the reaction mechanism such as multi-step processes or distortions.

The project for a precision measurement of the μp-capture rate (μCAP experiment) is based on an application of a multi-wire proportional chamber (MWPC) operating in ultra-pure hydrogen at 10bar pressure. A special test setup was constructed at PNPI to investigate the MWPC performance under the expected experimental conditions. The aging studies of the MWPCs were performed with intense irradiation from an α-source (241Am) and a β-source (90Sr). After 45 days of continuous irradiation by α-particles no changes in the currents, in the signal shapes, and in the counting rates were observed. It was demonstrated that the MWPCs can operate without degradation at least up to accumulated charges of 0.1C/cm wire. These irradiation conditions are much more severe than in the real experiment. During the study of the MWPC we have observed an appearance of short duration signals with amplitudes an order of magnitude larger than those of normal signals from the α-particles. The number of such signals (“streamers”) strongly depend on HV. We shall continue these tests in the future with the goal of obtaining more detailed information about aging properties of MWPCs operating with high-pressure hydrogen.

This work was carried out as part of a project aiming at a greatly improved measurement of the muon capture rate from the singlet state of the μp atom. The experiment will be performed at the intense muon beam of PSI using a new experimental method allowing high precision measurements of the lifetime of muons stopped in ultra-pure deuterium-depleted hydrogen (protium). The basic element of the detector is a time projection chamber operating in hydrogen gas at 10bar pressure. The arrival times and trajectories of the incoming muons and the outgoing decay electrons are measured with this device providing effective suppression of background. The system of chambers and electronics is designed for the large muon stop rates required for attaining high statistical accuracy. During four beam periods at PSI, data were taken. Also, various studies of the MWPC performance in hydrogen were made including ageing studies of the chambers under irradiation with stopped muons and with alpha and beta sources. It was demonstrated that the MWPCs can operate in pure hydrogen under 10 bar pressure with gas gains up to 5000, which is sufficient for the detection of relativistic electrons.