Source: http://www1.jinr.ru/Preprints/prepr_2017_eng.html
Timestamp: 2019-04-20 18:53:56+00:00

Document:
We present new results of the analysis of top-quark differential cross sections obtained by the CMS Collaboration in ρρ collisions within the z-scaling approach. The spectra are measured over a wide range of collision energy &Sqrt;s=7, 8, 13 TeV and transverse momentum ρT = 30–500 GeV/c of top-quark using leptonic and jet decay modes. Flavor independence of the scaling function ψ(z) is verified in the new kinematic range. The results of analysis of the top-quark spectra obtained at the LHC are compared with similar spectra measured in ρρ collisions at the Tevatron energy &Sqrt;s = 1,96 TeV. A tendency to saturation of ψ(z) for the process at low z and a power-law behavior of ψ(z) at high z is observed. The measurements of high ρT spectra of the top-quark production at the highest LHC energy is of interest for verification of self-similarity of particle production, understanding the flavor origin, and search for new physics symmetries with top-quark probe.
Dedovich T. G., Tokarev M. V.
Analysis of samples containing fractal and background events is performed using the method of systems of equations of P-adic coverages (SePaC) and Box Counting (BC) method. The features of these methods are studied. The procedures to indicate the existence of fractals in the combined sample, reconstruct fractals, estimate a fraction of fractals and estimate background in the extracted sample are suggested. The results of a comparative analysis of combined fractal samples using these methods are presented.
Pepelyshev Yu. N., Tsogtsaikhan Ts.
In this paper, we present the results of a study on pulse energy noise dynamics of the IBR-2M in the fuel burnup for a significant period of the reactor operation, starting from the date of its commissioning in 2011 and until the end of 2016. It is shown that the pulse energy noise during operation of the IBR-2M with burnup to about ∼1100 MW·day changes significantly by both the spectral component and the level. The standard deviation of the random power fluctuations did not exceed 5% and was less than allowable. In addition, the low level of low-frequency noise (∼1,6%) indicates the absence of sign of vibrational instability of the reactor and a substantial margin of burnup until instability.
The systematic study of the kinetics of UV-induced gene and structural mutations in eukaryotic cells was carried out on the basis of model yeast S. cerevisiae. A variety of genetic assays (all types of base pair substitutions, frameshifts, forward mutations canl, chromosomal and plasmid rearrangements) in haploid strains were used. Yeast cells were treated by UV-C light of fluence of energy up to 200 J/m2. The kinetics of the induced gene and structural mutations is represented by a linear-quadratic and exponential functions. The slope of curves in log-log plots was not constant, had the value 2-4 and depended on the interval of doses. It was suggested that it is the superposition and dynamics of different pathways form the mutagenic responses of eukaryotic cells to UV-C light that cause the high-order curves.
A formula is obtained for calculating the ion concentration profile in biological membranes. It is assumed that spherical ions move in an aqueous solution under the influence of an electric field and a concentration gradient. The friction force follows the Stokes law. The ions are covered with hydrate shells consisting of a dipole of water molecules which change their effective radius and friction. It is shown that if the friction force at the membrane inlet is stronger than at its outlet, then the ions can move by active transport. Analysis of the hydration allows the development of an analytical model of active and passive ion transport in membranes. The calculations are consistent with the concentration profile of Na+1, K+1 and Cl-1 measured in frog and squid cells.
The service life of the IBR-2 reactor, one of the leading pulse neutron sources in the world, is expected to end in 2032. Modern trends in sciences where neutrons are used, possible variants of a concept for a new neutron source and its potential position in the world neutron landscape are discussed. The flagship experiments for a new neutron source in the fields of condensed matter research, fundamental and nuclear physics are proposed.
Dolya S. N., Sarkhadov I.
This article considers the possibility of pulsed acceleration in a spiral waveguide of a proton beam with the current Ib = 0,7 A. The accelerator consists of three parts. The energy of the proton injection is 50 keV. In the first part of the accelerator having the length Lacc1 &approx; 1,4 m, the protons are accelerated up to the energy &varepsilon; 1fin = 0,8 MeV. In this section of the accelerator, consumption of high-frequency power is P1 = 0,8 MW. In the second part of the accelerator with the length Lacc2 &approx; 2 m, the protons are accelerated up to the energy &varepsilon; 2fin = 5 MeV. Consumption of high-frequency power in the second part of the accelerator is P2 = 4 MW. The third part of the accelerator consists of 8 sections, each being 7 m long. Radial focusing of the proton beam in this accelerator is carried out with the magnetic field intensity H = 10 , generated by a superconducting solenoid.
Agapov A. V., Mitsyn G. V.
The article considers the design and construction of a multichannel magnetic field measuring system using Hall sensors elaborated at the Medico-Technical Complex of the DLNP, JINR. The developed system allows monitoring magnetic induction fluctuations of the bending electromagnets of the proton therapy beamline. The thermostatic and power supply modules have been designed to solve the problem of thermal instability of Hall sensors. The set-point temperature of working volume of the Hall sensors is about 40°C with an accuracy of &pm; 0.05°С; and the precision of supply voltage is &pm; 1 mV. The multichannel magnetic field measuring system is routinely used in the proton therapy treatment sessions implementing the “quality assurance” of treatment.
Zinchenko Al. I. et al.
Requirements were considered and recommendations were formulated for the later technical design of the magnet for the SPD set-up. It has been shown that to get magnetic field homogeneity in the 1% limits for the whole inner solenoid volume, one has to use additional coils which must be placed in the end faces of the solenoid. The superconducting magnet is preferred to the warm version due to the lower weight and occupied volume of the coil, and the absence of the heat evacuation problem also.
Butenko A. V. et al.
Generation of magnetic field in the units of the booster synchrotron for the NICA project is one of the most important conditions for getting the required parameters and qualitative accelerator operation. Research of linear and nonlinear dynamics of the 197Au31+ ion beam in the booster was carried out with the MADX program. Analytical estimation of magnetic field errors tolerance and numerical computation of dynamic aperture of the booster DFO-magnetic lattice is presented. Closed orbit distortion with random errors of magnetic fields and errors in layout of the booster units was evaluated.
When developing charged particle detectors based on straw tubes working in vacuum, a special technique is needed for their mechanical properties evaluation. An experimental method of strained pressurized straw tube mechanical properties study is presented. The performed measurement results are in agreement with the approximate calculations taking into account the known uncertainties of the wall material parameters. It is shown that the difference between the tube wall longitudinal tension and the pressure force applied to the tube cross section area defines both the straw tube transverse stability and the lowest value of its oscillation frequency.
Derenovskaya О. Yu., Ivanov V. V., Ogorodnikova D. S.
Currently the CBM experiment is being developed in GSI (Darmstadt, Germany) at the FAIR accelerator complex of an international collaboration with JINR. Measurements of the J/ψ → e+e– decays are the key objectives of the CBM experiment, the registration of such decays is planned to be held in real-time experiment. The current paper presents criteria that provide an effective selection of signal events for Au + Au collisions at 10A GeV. This energy corresponds to the first stage of the CBM experiment.
(3q) + (3q) → (6q)cnf. It is admitted that central pp collisions in a definite range of the initial energy can lead to creation of an intermediate compound system where the hexa-quark dibaryon can be formed. Criteria for the selection of central collision events and for manifestation of the quark-structure dibaryon production are proposed.
Lenivenko V. V., Palichik V. V.
The algorithm for track reconstruction in the multiwire proportional chambers (MWPC) of the BM@N experiment is described. Beam tracks before the interaction with the target and trajectories of charged particles after the interaction are reconstructed using Nuclotron experimental data with deuteron and carbon beams colliding with the carbon and copper targets. Trajectories are extrapolated to the interaction point and to the drift chambers. Efficiencies of MWPCs have been obtained. Beam parameters (transverse dimensions, the angular spread) have been measured.
The avalanche breakdown and Geiger mode of the silicon p–n junction is considered. A precise physically motivated method is proposed for determining the avalanche breakdown voltage of silicon photomultipliers (SiPM). The method is based on measuring the dependence of the relative photon detection efficiency (PDErel) on the bias voltage when one type of carriers (electron or hole) is injected into the avalanche multiplication zone of the p–n junction. The injection of electrons or holes from the base region of the SiPM semiconductor structure is performed using short-wave or long-wave light. At a low overvoltage (1–2 V) the detection efficiency is linearly dependent on the bias voltage; therefore, extrapolation to zero PDErel value determines the SiPM avalanche breakdown voltage with an accuracy within a few millivolts.
Izosimov I. N. et al.
The experimental measurement data on the fine structure of beta-decay strength function Sβ (E) in spherical, transition, and deformed nuclei are analyzed. Modern high-resolution nuclear spectroscopy methods made it possible to identify the splitting of peaks in Sβ (E) for deformed nuclei. By analogy with splitting of the peak of E1 giant dipole resonance (GDR) in deformed nuclei, the peaks in Sβ (E) are split into two components from the axial nuclear deformation. In this report, the fine structure of Sβ (E) is discussed. Splitting of the peaks connected with the oscillations of neutrons against protons (E1 GDR), of proton holes against neutrons (peaks in Sβ (E) of β+/EC decay), and of protons against neutron holes (peaks in Sβ(E) of β– decay) is discussed.
Кiselev М. А. et al.
Small-angle X-ray scattering has been used to characterize the Phospholipid Transport Nanosystem (PTNS) at the PTNS concentrations in water of 25%, 31.25%, and 37.5%. The vesicle's average radius, size polydispersity, bilayer thickness, and internal structure were evaluated from the experiment via applications of two models for the photon scattering density distribution. Two independent methods were used for the calculation of the SAXS spectra: the form factor of the heterogeneous spherical shell and the method of separated form factors. Two methods of the spectra calculation and two models for the approximation of the photon scattering length density evaluation provide coincident results, which demonstrate the decrease in the vesicle radius, thickness of the bilayer, and thickness of the hydrocarbon chains region at the increase in the maltose concentration in water.
Terekhin A. A. et al.
The results of the differential cross section elastic dp-scattering measurements at 700 MeV/nucleon, performed at the Internal Target Station at the JINR Nuclotron, are presented. The data were obtained for angular range 70–120° in the c.m.s. The angular dependence is compared with the world experimental data at close energies as well as with the theoretical calculations performed within the framework of the relativistic multiple scattering theory.
An experimental method for the compensation of the noise originated by the laser ray angular oscillations was proposed and experimentally proved for the Precision Laser Inclinometer (PLI). The PLI noise spectral density was reduced by factor 30x and reached 10–8 rad/Hz1/2 level at the frequency of 5 ¢erdot; 10-5 Hz. The angular noise of a laser ray leaving the one-mode optical fiber in the vacuum and in stabilized temperature conditions has been measured. The amplitude of the oscillations for one-day observation reached 0.46 μrad.
For the Precision Laser Inclinometer (PLI) using the I-20A oil, a high-frequency 4~Hz boundary was determined for reliable detection of the Earth surface angular vibrations. The proposed method makes use of the microseismic signal and its processing to expand the PLI working interval for signal reception and allows one to record the narrow frequency-band signals originated by the Earth surface angular oscillations caused by industrial sources.
To reach a sensitivity level of ∼ 10-9 rad for the Precision Laser Inclinometer (PLI) for the registration of the Earth surface angular oscillation in the low frequency band of [10-6 Hz; 10-4 Hz] the temperature stability of the CERN Transfer Tunnel No. 1 has been investigated. The daily temperature variation was 0,082 °С for the air and 0,005 °С for the concrete floor. The last result opened the possibility to observe the Earth surface inclination caused by Moon and Sun if the PLI is thermally stabilized by the massive monolithic concrete floor of the tunnel.
A finite rank separable approach(FRSA) based on the quasi-particle random phase approximation with Skyrme interactions has been extended to describe charge-exchange excitation modes. The central and tensor residual interaction in both the particle-hole and particle-particle channel and the coupling between one- and two-phonon configurations are taken into account in the framework of the FRSA model. We study the effect of taking into account effective interactions in the particle--particle channel on beta-decay characteristics and the multi-neutron emission probabilities in the beta decay of 126,128,130,132Cd.
The neutron emission of the β-decay of 74,76,78,80Ni is studied with the Skyrme interaction taking into account the tensor terms. Calculations are performed within the quasiparticle random phase approximation. The coupling between one- and two-phonon terms in the wave functions of the low-energy 1+ states of the daughter nuclei is taken into account. It is shown that the strength decrease of the neutron-proton tensor interaction leads to the substantial increase of the half-life and the neutron-emission probability.
Ananiev V. D., Pepelyshev Yu. N., Rogov A. D.
The neutron-physical aspect of optimization of the IBR-2 pulsed reactor is considered in respect of whether it is possible in principle to design and construct reactor with a higher neutron flux density in beams, and if yes, how much higher it could be? The calculations have shown that the thermal neutron flux density in the beams can theoretically be increased up to (2.0–2.5)· 1013 cm–2 · s–1, and the cold neutron flux can be enhanced by three orders of magnitude. The latter is due to the fact that owing to the design peculiarities of the biological shield, the cold moderator at IBR-2 is used very inefficiently. It is shown that the increase in the flux density of thermal and cold neutrons is possible only if the reactor design is changed completely (decrease in the core volume, replacement of the fuel type with a denser one, and change in the system of beam extraction from the radial to tangential one). The technical implementation of these requirements for a such type of the reactor poses a significant problem. To sum up, the IBR-2 design developed by NIKIET in 1968 for generating short pulses of thermal (not cold) neutrons with an average flux density of ∼ 1013 cm -2 · s-1 was surprisingly well optimized.
A method for forming a continuous flux of monochromatic positrons with a controlled time of arrival at the target, independent of the start time in a limited start time interval, is suggested. Such an ordered positron flux (OPF) allows one to construct an experimental setup for studies of solid matter structure by positron annihilation spectroscopy (PAS) in its most efficient version — the Positron Annihilation Lifetime Spectroscopy (PALS). Simultaneously, by varying the potential of the target, one can control the energy of the positrons on the target and, accordingly, the depth of their penetration into the sample under study, measuring the distribution of defects in depth with high resolution.
The activation experiment was performed using the accelerated beam of the Phasotron accelerator at the Joint Institute for Nuclear Research (JINR). The natural uranium spallation target QUINTA was irradiated with protons of energy 660 MeV. Monte Carlo simulations were performed using the FLUKA and Geant4 codes. The number of leakage neutrons from the sections of the uranium target surrounded by the lead shielding and the number of leakage neutrons from the lead shield were determined. The total number of fissions in the setup QUINTA were determined. Experimental values of reaction rates for the produced nuclei in the 127I sample were obtained, and several values of the reaction rates were compared with the results of simulations by the FLUKA and Geant4 codes. The experimentally determined fluence of neutrons in the energy range of 10–200 MeV using the (n, xn) reactions in the 127I(NaI) sample was compared with the results of simulations. Possibility of transmutation of the long-lived radionuclide 129I in the QUINTA setup was estimated.
The use of laser radiation with tunable wavelength allows selective excitation of actinide / lanthanide species with subsequent registration of luminescence / chemiluminescence for their detection. This work is devoted to applications of the time-resolved laser-induced luminescence spectroscopy (TRLIF) and time-resolved laser-induced chemiluminescence spectroscopy (TRLIC) for detection of lanthanides and actinides in solutions. It is shown that a multistep scheme of chemiluminescence excitation provides highly sensitive and highly selective TRLIC procedure of detection of lanthanides and actinides in solutions.
Kovalchuk O. E. et al.
The results of irradiation of natural diamonds with fast 14.1 MeV neutrons, which are produced during the operation of a neutron separator for dry enrichment of kimberlite ore by the tagged neutron method, are discussed.
Bulavin M. V. et al.
The current paper covers results of the measurements of the fast neutron flux density by the method of neutron activation analysis (NAA) and measurements of the fluence equivalent to 1 MeV on the radiation damages of silicon detectors (Si-detectors), as well as γ-doses with usage of film-monitors at a considerable distance (3–8 m) from the IBR-2 water moderator WM-303 on the experimental beamline No.3. The results obtained can be used for determining the coordinates of the samples installed on the radiation research facility for beamline No. 3 aimed at their irradiation within the range of fluences from ∼ 5 ¢erdot; 1011 to 1015 n/cm2 (or with the flux density from ∼ 5 ¢erdot; 105 to 109 n/cm2/s).
Shabalin E. P. et al.
The basic concept and parameters of an advanced neutron source assigned for experiments using extracted beams based on the fission of neptunium isotope 237Np are presented. It is asserted that the highly intense source will possess unique properties both in the reactor and booster modes of operation, i.e., as a multiplying target of a proton accelerator. It will surpass all pulsed neutron facilities for neutron spectroscopy of modern times.
Revenko R. V. et al.
In order to investigate the secondary emission monitor for measuring the beam profile, a test of the profiler was performed on the extracted beam of the accelerator IC-100 of the Flerov Laboratory of Nuclear Reactions (FLNR JINR). The beam of 132Xe24+ ions with an energy of 1.2 MeV/A was used. The intensity varied from 10 to 100 nA. The measurements of the profile were carried out at different beam intensities in order to estimate the lower limit of the sensitivity of the monitor. As a result of the tests, it may be concluded that the lower intensity limit can be estimated at several hundredths of nA (∼ 0.05e nA).
A new arrangement of converters in the working volume of proportional and drift chambers is proposed for effective detection of X-rays. Positions and geometrical parameters of the converters entirely agree with kinematics of photoelectric absorption of gamma-rays by atoms. The preliminary experimental test confirms the possibility of significantly increasing the gamma detection efficiency of gas-filled detectors.
Panova T. D. et al.
The neutron activation analysis (NAA) of three samples of human remains of the XVI-XVII centuries from the necropolises of the Moscow Kremlin has been carried out at FLNP JINR. The samples were irradiated at two facilities — at the IREN source of resonance neutrons and at the IBR-2 reactor. Spectra of induced activity of the irradiated samples were measured by using the automatic measurement system developed at FLNP JINR. This system consists of a high-purity germanium detector with spectrometric electronics, a sample changer, and a control software. Mass fractions of arsenic, mercury and other elements were calculated by relative and absolute NAA methods. The obtained values confirmed the fact of an acute mercury poisoning of the first wife of Tsar Ivan Vasilievich the Terrible — Tsarina Anastasia Romanovna. Increased mercury content was detected in the bone remains of the son of Tsar Ivan the Terrible, Tsarevich Ivan Ivanovich, and Prince M. V. Skopin-Shuisky. The obtained results allow us to introduce into scientific circulation the exact values of mass fraction of mercury, arsenic and some other elements in the samples from the graves of Russian historical figures of the second half of XVI – early XVII centuries.
Angular distributions of protons, deuterons, tritons, and alpha particles emitted in the reaction 2H + 9Be at Elab = 19.5 MeV were measured to shed light on the internal cluster structure of 9Be and to study possible cluster transfer of 5He. The analyses suggest a significant contribution of a five-nucleon transfer in the 9Be (d, 4He)7Li reaction channel.
Были измерены инклюзивные энергетические спектры легких заряженных частиц, испускаемых при взаимодействии Ta-мишени с пучком 48Ca при энергиях 261 и 471 МэВ. Продукты реакции регистрировались с помощью ΔE – E телескопа, помещенного в фокальную плоскость магнитного спектрометра, расположенного под прямым углом относительно направления пучка. Во всех реакциях исследованы легкие заряженные частицы с энергией, близкой к соответствующему рассчитанному кинематическому пределу для выходного канала с двумя телами, с относительно большой вероятностью. Полученные результаты позволяют сделать некоторые выводы о механизме реакции, связанной с испусканием легких заряженных частиц.
Yuldasheva M. B., Yuldashev O.I.
Justification of a boundary least squares method with harmonic basis of a high order, which was formulated earlier by the authors, is given for 3D. For the linear div-curl systems with the Dirichlet conditions as well as with the mixed boundary conditions, weak formulations in spaces of piecewise-polynomial gradients of harmonic functions are obtained. Properties of bilinear forms and approximating properties of the basis are investigated. The h-convergence of approximate solutions is proved. In contrast to the primal formulation of the discontinuous Galerkin method, in this method the choice of a penalty weight function is not required.
The aim of this work is investigation of possibilities of using high-order harmonic basis for solving some magnetostatic problems. We consider known methods with our basis and the approach earlier elaborated by the authors. We present numerical results of their comparison when solving a linear problem on sequences of meshes with various parameters h and p. For a nonlinear problem with respect to two scalar potentials, it is shown that this model, in the suggested new weak formulation, keeps the property of monotonicity. From the results of this work it may be concluded that the harmonic basis gives more exact approximations on adaptive meshes for the considered magnetostatic problems in comparison with the usual approach.
Shabalin E. P., Rzjanin M. V.
Modern tendency in neutron research supposes development and construction of highly intense pulsed neutron sources. The pulsed reactor charged with fissionable isotope of neptunium-237 might be an option of the facility referred to in the text. The given work deals with analysis of power pulses dynamics of the neptunium reactor which accounts for fast temperature reactivity feedback within a single pulse. The problem was resolved with application of the simplified model of one-frequency oscillator combined with the point reactor kinetic equation neglecting delayed neutrons. It was shown that the calculated estimate of power pulse in nuclear accident appears to be less than one order of magnitude of that calculated without account for fast temperature reactivity feedback.
Nguyen N. A. et al.
For the purpose of enhancement of the experimental data set on the cascade intensities of two gamma quanta emitted step by step after radiative capture of thermal neutrons, the 171Yb (nth, 2γ) reaction was investigated. In the analysis of the cascade intensities a structure change of the observed levels of the 172Yb nucleus was discovered depending on the excitation energy, and the most probable breaking thresholds were obtained for four Cooper pairs of neutrons below neutron binding energy.
Mokrov Yu. V. et al.
The calculated results of the correspondence of indication of the dosimeter based on the 10B-counter with polyethylene moderator to the ambient dose equivalent behind the IBR-2M are presented. It was shown that the instrument can be used to measure the ambient dose with the uncertainty 25% in radiation monitoring at the reactor IBR-2M. The average value of the correction coefficient for this dosimeter behind the shield is 0.93.
The results of the indication correction for albedo dosimeters DVGN-01 using a spherical albedo system and of neutron spectra are presented. The measurements were carried out behind the IBR-2M shielding. The neutron spectra were measured in two places and the correction coefficients for DVGN-01 readout were estimated by these spectra. A good agreement was shown for the coefficients obtained with the help of these spectra and by the method of spherical albedo system. This is a real evidence of the correction method reliability.
Participation of the JINR group in the research at the Tevatron, Fermilab, is described. In their work on the upgraded CDF Run II detector, the emphasis was placed on top-quark physics. The JINR group took an active part in the analysis of the CDF data, specifically in measuring the top quark in the dilepton and lepton–jet modes, measuring the top-quark charge, and searching for the Higgs boson. The JINR group made a decisive contribution to the operation of the scintillation counter subsystem of the CDF muon trigger and a solid contribution to the trigger based on the vertex silicon detector for selection of events with secondary vertices and to the electromagnetic calorimeter preconverter. The group participated in the construction, upgrading, and operation of the system of scintillation counters and developed a system for the on-line monitoring of their parameters to ensure their effective operation in Run II. The work of the JINR scientists was highly appreciated by the international CDF collaboration.
Golubkov Е. А. et al.
The first results of startup and adjustment of the second accelerating section of the electron linear accelerator with an S-band traveling wave ( f = 2856 MHz) — the driver of the IREN facility (a neutron source of JINR FLNP)– are discussed. Key parameters of the accelerating system, RF power sources, modulators, accelerated beam, and neutron fluxes are presented.
Guzilov I. A. et al.
The results of testing the first prototype of the powerful pulse multibeam S-band klystron developed by DBT company are presented. Under the cathode voltage of 51.7 kV, beam current 205 А, and the measured RF peak pulse power 7 MW, the efficiency of the klystron reached 66.0%.
It is shown that when the parent nucleus has n–n Borromean halo structure, then after Gamow–Teller(GT) β–decay of parent state or after M1 γ decay of Isobar-Analogue Resonance (IAR) the states with n–p tango halo structure or mixed n–p tango + n–n Borromean halo structure can be populated. Resonances in the GT β–decay strength function Sβ(E) of halo nuclei may have n–p tango halo structure or mixed n–p tango + n–n Borromean halo structure. Correct interpretation of halo structure is important in experiments on β–decay study, treatment of M1 γ decay of IAR, and charge-exchange nuclear reactions analysis.
The properties of silicon and silicon carbide (SiC) detectors after their irradiation by different doses of xenon ions are presented. The irradiation of detectors was carried out at the IC-100 cyclotron at the Flerov Laboratory of Nuclear Reactions of JINR. It is shown that the degradation of spectroscopy characteristics of SiC detectors takes place at higher dose than the similar Si detectors used at experiments.
Every electronic system working in demanding conditions requires specific cooling system. To establish appropriate operating conditions for the TOF detector, it is necessary to measure and control the temperature. For this purpose, Pt100 resistance thermometer is used. We present one of the methods to verify functioning of the mentioned device.
The purpose of this project is to develop a control system for variable-energy positron beam's power supply unit. To solve this problem, proper hardware is chosen. In order to control the hardware, the software, divided into two separate programs, is developed. The paper explains what features the software delivers, why LabVIEW was used, and why the programs are divided.
Multi-Purpose Detector (MPD) is a part of the NICA project at JINR (Dubna). Among many control systems, Slow Control System (SCS) is dedicated to handle and control the parameters of detectors which vary with relatively slow sample rate and do not depend on the experiment. This paper describes the network analyzer used in the MPD supply racks as well as automation program made in LabVIEW. This device analyzes the main supply network parameters, e.g., current, power or voltage of each of 64 supply racks. Rack consists of many control subsystems, e.g., temperature control, gas control, and many others. In order to make these subsystems coherent in terms of data transmission, LabVIEW environment has been used. The network analyzer LabVIEW automation program is one part of the whole coherent automation system, containing a variety of subVI's connected by cluster links.
One of the main points of the project of technology and construction in the superconducting systems, being the part of the experiment on the electron cooling system of Nuclotron-based Ion Collider fAcility (NICA) project, is monitoring of the temperature, the liquid helium level in the cryostat, and magnetic field. In this paper, temperature monitoring system has been discussed. It is controled to protect against adverse heat supply. Therefore, the construction of temperature monitoring system should distinguish itself in terms of a large number of sensitive sensors, high accuracy of the sensor calibration. The following paper presents a prototype of the temperature monitoring system for the NICA project.
Neutron monitoring around high-energy accelerators cannot be organized only on the basis of standard (produced in the Russian Federation) dosimeters and neutron radiometers, since their operating range is limited by the neutron energy of ≈ 10 MeV. At the same time, higher-energy neutrons can make a significant contribution to the personnel dose both directly behind the accelerator shield and in the fields of scattered radiation in the environment. In this paper, we propose a method for measuring the ambient dose of neutrons in the neutron energy range of 10-2 MeV to 1 GeV based on two polyethylene spheres (3 and 10 inches in diameter with a lead converter $(10″ + Pb)) with slow neutron detectors inside. This method can be used mainly in fixed stations for area radiation monitoring around accelerators.
The SONIX+ software complex is designed as a unified control software for neutron spectrometers. At present, it is installed at the instruments of the IBR-2 reactor at the FLNP, JINR, as well as in a number of other centers of the Russian Federation — about 20 installations alltogether. The Python programming language is selected as the control language for scripting experimental procedure in the complex. The interpreter module is its most important part. This allowed not only to describe the instrument procedure specifics but also to include elements of preliminary processing of the results of measurements in a script. The work is devoted to the evolution of the script interpreter module — the most important element of the complex, reflecting the increasing complexity of both the instruments themselves and the measurement methodology.
The work is devoted to the development trends of the Sonix+ software complex, which is used as instrument control software at the IBR-2 reactor at the FLNP. Currently, the complex includes programs for direct control of beam experiments, the WebSonix system for remote measurement supervision and the Journal program for automatic registration of measurements. Development of all these components will be continued. The appearance of new devices in the setup, first of all, DAQ controllers Delidaq2 with USB3 interface, will be supported within the existing structure. Enhancement of network services is aimed at increasing the security, stability in operation and ease of use. Considerable attention will be paid to the development and implementation of the concept of a centralized repository of measurement results.
The aim of the project was determining the fast neutron flux density by using data from the Quinta experiment (E + T RAW collaboration), which took place on 4 December 2015 at the Veksler and Baldin Laboratory of High Energy Physics (VBLHEP), the Joint Institute for Nuclear Research (JINR). The experimental assembly based on natural uranium and an aluminum cover was irradiated by a 660 MeV proton beam from the Phasotron, DLNP, JINR. To gain the knowledge about the neutron flux inside the experimental assembly, nuclear threshold reactions of (n, xn) type were used. This paper describes the Quinta assembly, experimental results, calibration procedure and average high energy neutron calculation based on yttrium (Y-89) isotopes production. In the future, results and conclusions from an experiment like this could be useful to design accelerator-driven subcritical systems (ADS) or other 4th generation fast reactors. The paper is based on the 2016 Student Summer Practice work at JINR.
A numerical model of ionization in the plasma ion source, allowing for the electron impact and Penning effect, is presented. The influence of the Penning effect on the ionization efficiency is investigated. It is shown that the carrier gas can improve the ionization efficiency several times compared to the pure electron ionization case. Changes of the yield from the Penning ionization are investigated as a function of the carrier gas concentration, degree of ionization, and concentration of carrier gas atoms in the metastable state.
Volkov A. D. et al.
The theoretical analysis and results of testing the influence of internal pressure on the tension of welded thin-wall tubes from Mylar — straws, used for the creation of track detectors — are presented. Investigations have shown that under certain conditions the straw tension remains constant. A significant effect on the straw tension is exerted by a pressure difference on the end caps. Depending on the design of the gas supply, the pressure drop may be absent. Under this condition in a vacuum straw will be affected by a transverse stress, that partially reduces its creep, which increases the service life of the straw. At the same time in a vacuum straw is affected by a transverse stress, which partially reduces its creep that increases the service life of the straw. The presence of a pressure difference can contribute to an increase in creep. The test results of the pressure influence confirm the obtained dependences, which can be relied upon in the creation of straw detectors for operation in vacuum. A specific technique for measuring a real straw's Poisson ratio is proposed. This value is required to evaluate the effect of pressure on the tension of welded straws. Its value for the straw tubes of the COMET detector is 0.338.
A holistic description means a single algorithmic approach to the formation of the equations for the lepton sector. The sequence of the actions required for formulation of free lepton equations was established on the basis of group-theoretical analysis of the Dirac (1928), Pauli (1932) and Majorana (1937) equations. The given sequence of actions is called below the Dirac algorithm. A generalization of the Dirac algorithm was found for unstable leptons. As a result, we obtained three types of equations. Two of them are connected with the unstable charged leptons (μ±, τ±), the third is connected with a massive unstable neutrino. Lorentz invariance and the covariance of the unstable equation recording are performed with the same degree of rigor as for the Dirac equation. One of the consequences of the developed by us approach was the discovery of the individual structure of each lepton equation. Other consequences of taking into account the structure of the leptons are as follows: the existence of massive unstable neutrino is predicted; the existence of «doublets» for τ±-leptons, i.e. (τ*)±-leptons, is predicted; a primary structural classification of leptons was made up.

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