Preprints and Communications

Here you can find JINR preprints and communications in pdf format starting from 1999.
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2012

P10-2012-1 (2.661.239) Kulakov I.S. et al. Perfomance Analysis of a Cellular Automaton Algorithm for the Solution of the Track Reconstruction Problem on a Manycore Server at LIT, JINR The results of the tests for the tracks reconstruction efficiency, the speed of the algorithm and its scalability with respect to the number of cores of the server with two Intel Xeon E5640 CPUs (in total 8 physical or 16 logical cores) are presented and discussed. E2-2012-2 (168.559) Lyuboshitz V.L., Lyuboshitz V.V. Lepton Mixing under the Lepton-Charge Nonconservation, Neutrino Masses and Oscillations and the «Forbidden» Decay The lepton-charge (Le, L, L) nonconserving interaction leads to the mixing of the electron, muon, and tau neutrinos, which manifests itself in spatial oscillations of a neutrino beam, and also to the mixing of the electron, negative muon, and - lepton, which, in particular, may be the cause of the «forbidden» radiative decay of the negative muon into the electron and quantum. Under the assumption that the nondiagonal elements of the mass matrices for neutrinos and ordinary leptons, connected with the lepton-charge nonconservation, are the same, and by performing joint analysis of the experimental data on neutrino oscillations and experimental restriction for the probability of the decay per unit time, the following estimate for the lower bound of neutrino mass has been obtained: m() > 1.5 eV/c2. P10-2012-7 (307.777) Slepov I.P., Ososkov G.A., Rogachevsky O. Informational Support for Software Development of the MPD Experiment at the NICA Collider The article presents a web-site which carries information for users and software developers of the MPD experiment at the NICA collider. It describes usage of the content management system Drupal for the site creation and tools useful for the software developers of the experiment. E2-2011-8 (100.061) Beshtoev Kh.M. About Direct CP Violation in the System of K0 mesons This work is devoted to computation of the parameter of direct CP violation by the weak interactions in the system of K0 mesons at K10-, K20-meson mixings and oscillations via KS-, KL-meson states. P13-2012-11 (2.971.770) Kruchonak U. et al. The Device for Measuring Light Attenuation in the WLS Fibers The device that allows accurate and fast measurement of optical characteristics (light output and attenuation length) of wavelength shifting (WLS) fibers is described. This device was used for test and selection of fibers for the Target Tracker detector of OPERA experiment. After modification the device was used for the studying and selection of WLS fibers for the electromagnetic calorimeter ECAL0 of the COMPASS detector. E2-2012-12 (265.731) Tokarev M.V., Zborovsk On Self-Similarity of Top Production at Tevatron Results of analysis of D 1.0 fb1 data on top-quark differential cross section measurements at the Fermilab Tevatron collider at = 1960 GeV in the framework of z-scaling approach are presented. Flavour independence of the scaling function (z) observed in pp and interactions over a wide collision energy range = 19-1960 GeV is verified. This property of (z) was found for different hadrons from meson up to particle. The flavour independence of (z) is used as indication to self-similarity of top-quark production. A tendency to saturation of (z) at low z for top-quark is demonstrated. The momentum fractions x1 of the incoming (anti)protons as a function of the scaled transverse momentum pT/m and masses of heavy mesons are studied. We anticipate that data on low- and high-pT inclusive spectra of top-quark production at Tevatron and LHC energies could be of interest for verification of the self-similarity over a wide range of masses and different flavour content of produced particles. E1-2012-13 (930.639) Baatar Ts. et al. A Possible Study of the Phase Transition in -C Interaction at 40 GeV/c In this paper we consider the momentum and angular characteristics of protons and - mesons produced in -C interactions at 40 GeV/c as a function of the cumulative number nk (or the four-dimensional momentum transfer t). Analysis carried out in this paper indicates possible appearance of the phase transition of nuclear matter. P8-2012-14 (2.877.207) Agapov N.N. et al. Development and Reconstruction of VBLHEP Cryogenic System for NICA Accelerator Complex (2012-2015) A new NICA accelerator complex (Nuclotron-based Ion Collider fAcility), presently under construction at JINR, will be, upon its completion in 2016, among the most advanced research instruments of the physics community. The facility is aimed to provide collider experiments with heavy ions up to uranium (gold at the beginning stage) with a centre of mass energy up to 11 GeV/u and an average luminosity up to 1027 cm-2 s-1. The NICA cryogenics will be based on the modernized liquid helium plant that was built in the early 1990s for the superconducting synchrotron known as Nuclotron. The main goals of the modernization are increasing of the total refrigerator capacity from 4000 to 8000 W at 4.5 K, creating a new distribution system of liquid helium, and ensuring the shortest possible cooldown time. These goals will be achieved by the use of an additional 1000 l/h helium liquefier and «satellite» refrigerators located in close proximity to the accelerator rings. We demonstrate helium flow diagrams with major new components and discuss a system of liquid nitrogen that will be used for shield refrigerating at 77 K and at the first stage of cooling down of three accelerator rings with total length of about 1 km and «cold» mass of 220 t. P13-2012-16 (236.117) Pepelyshev Yu.N. et al. Experimental Estimations of the Kinetics Parameters of the IBR-2М Reactor by Stochastic Noises Experimental investigations of stochastic fluctuations of pulse energy of the IBR-2M reactor have been carried out which allowed us to obtain some of the parameters of the reactor kinetics. At different levels of average power a sequence of values of pulse energy was recorded with the calculation of the distribution parameters. An ionization chamber with boron installed near the active zone was used as a neutron detector. The research results allowed us to estimate the average lifetime of prompt neutrons = (6.53 0.2) 10-8 s, absolute power of the reactor and intensity of the source of spontaneous neutrons Ssp (6.72 0.12) 106 s-1. It was shown that the experimental results are close to the calculated ones. E1-2012-17 (605.859) Piyadin S.M. et al. First Extraction of the 3.42A GeV 12C Beam for Studies of Baryonic Matter at the Nuclotron The results of the first extraction of the 3.42A GeV 12C beam at the Nuclotron and its transportation to the experimental area are presented. It is demonstrated that the beam parameters are sufficient for the first phase of the experiments on the studies of the dense baryonic matter at the Nuclotron. E2-2012-19 (1.264.336) Tokarev M.V., Dedovich T.G., Zborovsk I. Self-Similarity of Jet Production in pp and Collisions at RHIC, Tevatron, and LHC Self-similarity of jet production in pp and collisions is studied in the framework of z scaling. Inclusive jet transverse momentum distributions measured by the STAR Collaboration at RHIC, the CDF and D Collaborations at Tevatron, and the CMS and ATLAS Collaborations at LHC are analyzed. The experimental spectra are compared with next-to-leading order QCD calculations in pT and z presentations. It is shown that self-similar features of jet cross sections manifested by the z scaling give strong restriction on the scaling function (z) at high z. New results on energy and angular independence and asymptotic behavior of (z) are discussed. The obtained results are considered as confirmation of self-similarity of jet production, fractality of hadron structure, and locality of constituent interactions at small scales. P17-2012-23 (895.577) Eremin R.A. et al. Molecular Dynamics Simulations of Monocarboxylic Acid Solutions in Decalin Pure decalin solutions are investigated using the molecular dynamics simulation method at different contents of stereoisomers. Limiting solutions of monocarboxylic acids with different length of the hydrocarbon chains are studied. A comparison of the features of the structural organization of decalin stereoisomers in the vicinity of saturated (myristic and stearic) and non-saturated (oleic) acid molecules is carried out. The limiting partial molar volumes of the acids are calculated using radial distribution functions. In contrast to earlier data on benzene, a significant difference in the volumes of stearic and oleic acids is observed and explained by the more complex molecular structure of decalin, which is sensitive to the bending of the non-saturated acid molecule. P9-2012-24 (2.683.863) Denisov Yu.N. et al. Computer Modeling of the Acceleration of Low Charge Krypton Ions in Cyclotron CYTRACK The basic results of numeric simulations of krypton ion motion with decreased charge in cyclotron CYTRACK are presented. Cyclotron CYTRACK is the first world industrial cyclotron dedicated to produce the track membranes. Computer modeling confirms the possibility of 84Kr+11 ion acceleration in the formed magnetic field with increase of the magnetic field level by 1.6% on the sixth harmonic of the accelerating system. Beam energy will be sufficient for exposure of the film with thickness 10 m. P9-2012-28 (576.122) Zhabitsky V.M. Transient Beam Response in Synchrotrons with a Digital Transverse Feedback System The transient beam response on an externally applied impulse force in synchrotrons with a digital transverse feedback system is studied. Experimental data from the LHC on damping of coherent transverse oscillations excited by the discrete-time unit impulse are analysed. Good agreement on the measured and theoretically predicted decrements has been obtained. A method of feedback fine tuning, based on measurements of bunch response to harmonic excitation impulse, is discussed. E14-2012-31 (390.955) Kalabegishvili T. et al. Synthesis of Gold Nanoparticles by Blue-Green Algae Spirulina platensis The synthesis of gold nanoparticles by one of the many popular microorganisms - blue-green algae Spirulina platensis was studied. The complex of optical and analytical methods was applied for investigation of experimental samples after exposure to chloroaurate (HAuCl4) solution at different doses and for different time intervals. To characterize formed gold nanoparticles UV-vis, TEM, SEM, EDAX, and XRD were used. It was shown that after 1.5-2 days of exposure the extracellular formation of nanoparticles of spherical form and the distribution peak within the interval of 20-30 nm took place. To determine gold concentrations in the Spirulina platensis biomass, neutron activation analysis (NAA) and atomic absorption spectrometry (AAS) were applied. The results obtained evidence that the concentration of gold accumulated by Spirulina biomass is rapidly growing in the beginning, followed by some increase for the next few days. The obtained substance of Spirulina biomass with gold nanoparticles may be used for medical, pharmaceutical, and technological purposes. E5-2012-38 (214.779) Zhidkov P.E. On Weak Solutions of the Initial Value Problem for the Equation utt=a(x, t)uxx + f(t, x, u, ut, ux) For the equation of the kind indicated in the title, it is assumed roughly speaking that and and that there exist 0 < a1 < a2 and a3 > 0 such that a1 a(x, t) a2 and | a(x, t)| a3 for any . The function f is assumed to be continuously differentiable and satisfying f(t, x, 0, r, s) 0. The initial data are assumed to be in . The existence and uniqueness of a local weak -solution is proved. In addition, in the special case f(t, x, u, ut, ux) = -|uq-1|u, q 1 the existence of a global weak solution is proved. E1-2012-39 (63.061) Kukhtin V.V. et al. New Approaches for Searching for the Dirac Magnetic Monopole Three new approaches, not applied earlier, are proposed to search for the Dirac monopole - an object whose existence was proposed by P. Dirac more than 80 years ago to explain the electrical charge quantization. The first approach assumes that the monopole must be accelerated by a magnetic field, and such acceleration is constant in the magnetic field which is homogeneous and constant. The conclusion about the object movement nature can be drawn by measuring the time marks for equidistant registering planes. The second approach is supposed to reconstruct the movement trajectory in the homogeneous and permanent electrical field, which is the circle or its part for the magnetic monopole. The third approach is based on the constancy of energy losses by Dirac monopole due to medium ionization in the multilayer passive dielectric tracking detectors placed in the homogeneous and permanent electrical field. P13-2012-41 (1.216.862) Ananiev V.D. et al. Physical Start-up of the IBR-2 Modernized Reactor Here we present the main results of the investigation of the IBR-2 reactor after the completion of its modernization, which was carried out within the framework of the program of the physical start-up of the reactor in 2010-2011 operated at a low power of up to 30 kW. The IBR-2 reactor was shut down in 2006 since it reached its design service life limits. A considerable part of the reactor main equipment was replaced except for a biological shield, reactivity modulator and technological systems. According to the results of the physical start-up of the modernized IBR-2 reactor the critical loading of the core was 64 fuel assemblies. The remaining uncharged five cells will ensure the reactor service life for no less than 20 years. The efficiency of the control roads of the reactor safety system and the operating speed of the emergency protection system units meet the nuclear safety requirements. The imitation of the accidents connected with the failures of various technological systems that maintain normal functioning of the reactor has demonstrated that in all cases the reactivity insertion rate is less than the acceptable value and the emergency protection system units in any situation will decrease the reactor power to a safe level during the period between pulses. The fast neutron pulse shape is close to Gaussian with a halfwidth at maximum of (220 3) s. Mean square values of the pulse energy fluctuations do not exceed 5%. The technological systems of the reactor during the physical start-up operated trouble free. P13-2012-42 (294.132) Ananiev V.D. et al. First Power of the IBR-2 Modernized Reactor We present the main results of the investigation of the modernized IBR-2 reactor carried out within the framework of the program of the power start-up of the reactor in 2011 operated at a power of up to rated 2 MW. According to the results of the power start-up the reactor and its technological systems operated without fail. The new safety control system meets all design objectives and makes it possible to decrease the reactor power to a safe level during the period between pulses. All fast feedbacks (power, flow and isothermal effect) are negative at all levels of power and sodium coolant flow rate through the core. Pulse energy fluctuations are small (5.9% mean square) and considerably less than those of IBR-2 before its shutdown for modernization. The full width at half maximum is (200 4) s, which is less than for IBR-2 in 2004 ((245 4) s). The peak pulse power is 1830 MW, background between pulses 8.6% of mean power. The above-mentioned parameters allow the reactor to maintain its safe and efficient operation at a power of 2 MW at a pulse repetition rate of 5 s-1. P13-2012-46 (475.174) Bogdzel A.A. et al. Experiment Automation System for a Neutron Powder Diffractometer The study is concerned with the modernization of a detector system and a control system of the neutron powder diffractometer (NPD) on the GEK-5 channel of the VVR-c reactor (Obninsk branch of the Karpov Institute of Physical Chemistry). In the course of the work a PC-connected hardware-software complex providing for data acquisition and accumulation, as well as for experiment control, has been created. The main modules of the automation system of NPD and the software complex Sonix+ developed in FLNP, JINR, are briefly described. As a result of the modernization the luminosity of the diffractometer has increased and the measurement process has become fully automated. P6-2012-48 (170.040) Rakhimov A.V. et al. Purification of Selenium from Thorium, Uranium, Radium, Actinium and Potassium Impurities for the Low Background Measurements The new generation of rare event searches experiments requires a new level of very high radiopurity. Main impurities come from the natural long-lived radionuclides Th, U, Ra, Ac and K. In the frame of this field purification of Se polluted with those radioimpurities was carried out taking special care of radiopurity of any reagent used. Аn instrumental neutron activation analysis of bidistillated water, deionized water and nitric acid was performed. These reagents were used during the process of selenium purification from impurities of Th, U, Ra, Ac and K using the reverse method. Distribution coefficients of 234Th, 230U, 223Ra, 225Ac on the cation-exchange resin DOWEX 50W-X8 in different concentrations of selenium and nitric acid were experimentally measured. The technique of selenium purification from Th, U, Ra, Ac and K was developed. The developed technique of selenium purification has a simple technology of execution and minimal number of reagents (water, nitric acid) which possess a high degree of cleanliness. Operations applied during purification (elution, evaporation) practically exclude losses of a target product (chemical yields of Se > 99 %). Based on this technique test purification of 100 g selenium was carried out. The efficiency of this technique was confirmed by low background spectrometry of purified selenium sample. E7-2012-58 (178.277) Oganessian Yu. Ts. et al. New Insights into the 243Am + 48Ca Reaction Products Previously Observed in the Experiments on Elements 113, 115, and 117. II We continued experiments on measuring excitation functions of the reaction 243Am + 48Ca and investigation of radioactive properties of isotopes of element 115 that were started in 2010-2011, now at two projectile energies of 241 and 254 MeV. At the lowest energy of 48Ca, we registered seven decay chains of 288115 and three decay chains of the 2n-evaporation product, 298115, which was also observed previously in the reaction 249Bk + 48Ca as the daughter nucleus of the decay of 293117. At the beam energy of 254 MeV one decay chain of 287115 was detected. Altogether thirty-one decay chains originating from 288115 were established as the product of the 3n-evaporation channel by measuring the excitation function at five excitation energies of the compound nucleus 291115. The decay properties of all the newly observed nuclei 287115, 288115 and their descendant nuclides are in full agreement with those we measured in 2003. The -particle energies and decay times of the isotopes 289115, 285113, and 281Rg produced in cross reactions with the two target nuclei 243Am and 249Bk agree well to provide cross bombardment evidence for the discovery of the new elements 113, 115, and 117.

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