WorldWideScience

Sample records for neutron matter exotica

  1. Exotica in CMS

    CERN Document Server

    AUTHOR|(CDS)2072123

    2015-01-01

    Selected results on exotica searches with the CMS detector are presented. The main topics are dark matter, boosted objects, long-lived particles and classic narrow resonance searches. Most of the analyses were performed with data recorded at at centre-of-mass energy of 8 TeV, but first results obtained at 13 TeV are also shown.

  2. Neutrons for probing matter

    International Nuclear Information System (INIS)

    Torres, F. Ed.; Mazzucchetti, D.

    2008-01-01

    The authors tell the story of the French Orphee reactor located in Saclay from the decision to build it in the seventies, to its commissioning in 1980, to its upgrading in the nineties and to its today's operating life. As early as its feasibility studies Orphee has been designed as a dual-purpose reactor: scientific research for instance in crystallography and magnetism, and industrial uses like neutron radiography, silicon doping or radionuclide production. This book is divided into 4 parts: 1) the neutron: an explorer of the matter, 2) the Orphee reactor: a neutron source, 3) the adventurers of the matter: Leon Brillouin laboratory's staff, and 4) the perspectives for neutrons

  3. Neutron stars as cosmic neutron matter laboratories

    International Nuclear Information System (INIS)

    Pines, D.

    1986-01-01

    Recent developments which have radically changed our understanding of the dynamics of neutron star superfluids and the free precession of neutron stars are summarized, and the extent to which neutron stars are cosmic neutron matter laboratories is discussed. 17 refs., 1 tab

  4. Neutron matter, symmetry energy and neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, Gandolfi [Los Alamos National Laboratory (LANL); Steiner, Andrew W [ORNL

    2016-01-01

    Recent progress in quantum Monte Carlo with modern nucleon-nucleon interactions have enabled the successful description of properties of light nuclei and neutron-rich matter. Of particular interest is the nuclear symmetry energy, the energy cost of creating an isospin asymmetry, and its connection to the structure of neutron stars. Combining these advances with recent observations of neutron star masses and radii gives insight into the equation of state of neutron-rich matter near and above the saturation density. In particular, neutron star radius measurements constrain the derivative of the symmetry energy.

  5. First Run 2 Searches for Exotica at CMS

    CERN Document Server

    Başeğmez du Pree, S

    2016-01-01

    An overview of the first results of the experimental searches for exotica at the CMS experiment with 13 TeV collision data is presented. The results cover various models with different topologies such as searches for new heavy resonances, extra space dimensions, black holes and dark matter. The analysis results with 13 TeV data are emphasized, corresponding to an integrated luminosity in the range of 2.1–2.8 fb

  6. LHCb Exotica and Higgs searches

    CERN Multimedia

    Lucchesi, Donatella

    2016-01-01

    The unique phase space coverage and features of the LHCb detector at the LHC makes it an ideal environment to probe complementary New Physics parameter regions. In particular, recently developed jet tagging algorithms are ideal for searches involving $b$ and $c$ jets. This poster will review different jet-related exotica searches together with the efforts in the search for a Higgs boson decaying to a pair of heavy quarks.

  7. Thermodynamics of neutron-rich nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    López, Jorge A., E-mail: jorgelopez@utep.edu [Department of Physics, University of Texas at El Paso, El Paso, Texas 79968, U.S.A (United States); Porras, Sergio Terrazas, E-mail: sterraza@uacj.mx; Gutiérrez, Araceli Rodríguez, E-mail: al104010@alumnos.uacj.mx [Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, Chihuahua, México (Mexico)

    2016-07-07

    This manuscript presents methods to obtain properties of neutron-rich nuclear matter from classical molecular dynamics. Some of these are bulk properties of infinite nuclear matter, phase information, the Maxwell construction, spinodal lines and symmetry energy.

  8. Differential rotation of viscous neutron matter

    International Nuclear Information System (INIS)

    Nitsch, J.; Pfarr, J.; Heintzmann, H.

    1976-08-01

    The reaction of homogeneous sphere of neutron matter set in rotational motion under the influence of an external torque acting on its surface is investigated. For neutron matter with a typical neutron star density of 10 15 gcm -3 and a temperature varying between 10 6 and 10 9 K originally in uniform rotation, a time dependent differential motion sets in, which lasts a time scale of hours to some decades, resulting finally in co-rotation. During these times the braking index of a magnetic neutron sphere very sensitively depends on time

  9. Thermal and magnetic properties of neutron matter

    International Nuclear Information System (INIS)

    Abd-Alla, M.; Ragab, H.S.; Hassan, M.Y.M.

    1990-01-01

    The Thomas-Fermi model is used to calculate the equation of state of thermal polarized neutron matter applying Seyler-Blanchard interaction. The resulting equation of state is stiff and has a small dependence on both the temperature and the spin excess parameter. We expand the Fermi integrals in powers of temperature up to second order to examine the T 2 approximation for neutron matter. It is found to be reliable up to T = 10 MeV. We also studied the ferromagnetic transition in neutron matter. We found a ferromagnetic transition at density ρ ≅ 2ρ0. This ferromagnetic transition is found to have a small dependence on both the temperature and the spin excess parameter. We also studied the dependence of the effective mass and the sound velocity for polarized neutron matter on temperature. (author). 36 refs, 17 figs

  10. The behaviour of neutron bursts in matter

    International Nuclear Information System (INIS)

    Syros, C.

    1978-01-01

    An exact method is developed for solving the time-dependent linear transport equation for neutrons. The problem of finding the behaviour of neutron bursts in matter have been considered. The method leads to a new kind of perturbation theory applicable to the transport theoretical reactor dynamics. Applications of the theory are given for discontinuously or continuously distributed initial values of the neutron population. The boundary and initial conditions are exactly fulfilled. (author)

  11. Thermal compression modulus of polarized neutron matter

    International Nuclear Information System (INIS)

    Abd-Alla, M.

    1990-05-01

    We applied the equation of state for pure polarized neutron matter at finite temperature, calculated previously, to calculate the compression modulus. The compression modulus of pure neutron matter at zero temperature is very large and reflects the stiffness of the equation of state. It has a little temperature dependence. Introducing the spin excess parameter in the equation of state calculations is important because it has a significant effect on the compression modulus. (author). 25 refs, 2 tabs

  12. Quark matter droplets in neutron stars

    Science.gov (United States)

    Heiselberg, H.; Pethick, C. J.; Staubo, E. F.

    1993-01-01

    We show that, for physically reasonable bulk and surface properties, the lowest energy state of dense matter consists of quark matter coexisting with nuclear matter in the presence of an essentially uniform background of electrons. We estimate the size and nature of spatial structure in this phase, and show that at the lowest densities the quark matter forms droplets embedded in nuclear matter, whereas at higher densities it can exhibit a variety of different topologies. A finite fraction of the interior of neutron stars could consist of matter in this new phase, which would provide new mechanisms for glitches and cooling.

  13. Magnetic properties of neutron-star matter

    Energy Technology Data Exchange (ETDEWEB)

    Chao, N C [PERNAMBUCO UNIV., RECIFE (BRAZIL). INSTITUTO DE FISICA; CLARK, J W [WASHINGTON UNIV., ST. LOUIS, MO. (USA)

    1975-08-01

    An array of qualitative and quantitative evidence is presented to the effect that neutron-star matter in its ground state is antiferromagnetic rather than ferromagnetic. The energy of pure neutron matter is evaluated as a function of spin polarization by a two-body Jastrow procedure, for densities up to five times that of ordinary nuclear matter. The anti-ferromagnetic state is energetically preferred to states with non-zero spin polarization, and lies considerably lower in energy than the ferromagnetic state. The magnetic susceptibility of the material is calculated as a function of density in the same approximation, with results which are in good agreement with independent estimates.

  14. Magnetic properties of neutron-star matter

    International Nuclear Information System (INIS)

    Chao, N.C.

    1975-01-01

    An array of qualitative and quantitative evidence is presented to the effect that neutron-star matter in its ground state is antiferromagnetic rather than ferromagnetic. The energy of pure neutron matter is evaluated as a function of spin polarization by a two-body Jastrow procedure, for densities up to five times that of ordinary nuclear matter. The anti-ferromagnetic state is energetically preferred to states with non-zero spin polarization, and lies considerably lower in energy than the ferromagnetic state. The magnetic susceptibility of the material is calculated as a function of density in the same approximation, with results which are in good agreement with independent estimates [pt

  15. Neutron rich matter, neutron stars, and their crusts

    International Nuclear Information System (INIS)

    Horowitz, C J

    2011-01-01

    Neutron rich matter is at the heart of many fundamental questions in Nuclear Physics and Astrophysics. What are the high density phases of QCD? Where did the chemical elements come from? What is the structure of many compact and energetic objects in the heavens, and what determines their electromagnetic, neutrino, and gravitational-wave radiations? Moreover, neutron rich matter is being studied with an extraordinary variety of new tools such as Facility for Rare Isotope Beams (FRIB) and the Laser Interferometer Gravitational Wave Observatory (LIGO). We describe the Lead Radius Experiment (PREX) that is using parity violation to measure the neutron radius in 208Pb. This has important implications for neutron stars and their crusts. Using large scale molecular dynamics, we model the formation of solids in both white dwarfs and neutron stars. We find neutron star crust to be the strongest material known, some 10 billion times stronger than steel. It can support mountains on rotating neutron stars large enough to generate detectable gravitational waves. Finally, we describe a new equation of state for supernova and neutron star merger simulations based on the Virial expansion at low densities, and large scale relativistic mean field calculations.

  16. Constraining neutron star matter with Quantum Chromodynamics

    CERN Document Server

    Kurkela, Aleksi; Schaffner-Bielich, Jurgen; Vuorinen, Aleksi

    2014-01-01

    In recent years, there have been several successful attempts to constrain the equation of state of neutron star matter using input from low-energy nuclear physics and observational data. We demonstrate that significant further restrictions can be placed by additionally requiring the pressure to approach that of deconfined quark matter at high densities. Remarkably, the new constraints turn out to be highly insensitive to the amount --- or even presence --- of quark matter inside the stars.

  17. Neutron stars with spin polarized self-interacting dark matter

    OpenAIRE

    Rezaei, Zeinab

    2018-01-01

    Dark matter, one of the important portion of the universe, could affect the visible matter in neutron stars. An important physical feature of dark matter is due to the spin of dark matter particles. Here, applying the piecewise polytropic equation of state for the neutron star matter and the equation of state of spin polarized self-interacting dark matter, we investigate the structure of neutron stars which are influenced by the spin polarized self-interacting dark matter. The behavior of the...

  18. The neutrino opacity of neutron rich matter

    Energy Technology Data Exchange (ETDEWEB)

    Alcain, P.N., E-mail: pabloalcain@gmail.com [Departamento de Física, FCEyN, UBA and IFIBA, Conicet, Pabellón 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); IFIBA-CONICET (Argentina); Dorso, C.O. [Departamento de Física, FCEyN, UBA and IFIBA, Conicet, Pabellón 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); IFIBA-CONICET (Argentina)

    2017-05-15

    The study of neutron rich matter, present in neutron star, proto-neutron stars and core-collapse supernovae, can lead to further understanding of the behavior of nuclear matter in highly asymmetric nuclei. Heterogeneous structures are expected to exist in these systems, often referred to as nuclear pasta. We have carried out a systematic study of neutrino opacity for different thermodynamic conditions in order to assess the impact that the structure has on it. We studied the dynamics of the neutrino opacity of the heterogeneous matter at different thermodynamic conditions with semiclassical molecular dynamics model already used to study nuclear multifragmentation. For different densities, proton fractions and temperature, we calculate the very long range opacity and the cluster distribution. The neutrino opacity is of crucial importance for the evolution of the core-collapse supernovae and the neutrino scattering.

  19. Neutron slowing-down time in matter

    Energy Technology Data Exchange (ETDEWEB)

    Chabod, Sebastien P., E-mail: sebastien.chabod@lpsc.in2p3.fr [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut Polytechnique de Grenoble, 38000 Grenoble (France)

    2012-03-21

    We formulate the neutron slowing-down time through elastic collisions in a homogeneous, non-absorbing, infinite medium. Our approach allows taking into account for the first time the energy dependence of the scattering cross-section as well as the energy and temporal distribution of the source neutron population in the results. Starting from this development, we investigate the specific case of the propagation in matter of a mono-energetic neutron pulse. We then quantify the perturbation on the neutron slowing-down time induced by resonances in the scattering cross-section. We show that a resonance can induce a permanent reduction of the slowing-down time, preceded by two discontinuities: a first one at the resonance peak position and an echo one, appearing later. From this study, we suggest that a temperature increase of the propagating medium in presence of large resonances could modestly accelerate the neutron moderation.

  20. Asymmetric nuclear matter and neutron star properties

    International Nuclear Information System (INIS)

    Engvik, L.; Hjorth-Jensen, M.; Osnes, E.; Bao, G.; Oestgaard, E.

    1994-06-01

    Properties of neutron stars such as mass and radius, using a relativistic Dirac-Brueckner-Hartree-Fock approach, are calculated. Modern meson-exchange potential models are used to evaluate the G-matrix for asymmetric nuclear matter. For pure neutron matter the maximum mass is found to be M max ∼ 2.4M for a radius R ∼ 12 km. With a proton fraction of 30% the result is M max ∼ 2.1M for a radius R ∼ 10.5 km, close to the experimental values. The implications are discussed. 20 refs., 3 figs

  1. Quasiparticle Interactions in Neutron Matter for Applications in Neutron Stars

    Science.gov (United States)

    Wambach, J.; Anisworth, T. L.; Pines, D.

    1993-01-01

    A microscopic model for the quaisiparticle interaction in neutron matter is presented. Both particle-particle (pp) and particle-hole (ph) correlation are are included. The pp correlations are treated in semi-empirical way, while ph correlations are incorporated by solving coupled two-body equations for the particle hole interaction and the scattering amplitude on the Fermi sphere. The resulting integral equations self-consistently sum the ph reducible diagrams. Antisymmetry is kept at all stages and hence the forward-scattering sum rules are obeyed. Results for Landau parameters and transport coefficients in a density regime representing the crust of a neutron star are presented. We also estimate the S-1 gap parameter for neutron superfluidity and comment briefly on neutron-star implications.

  2. Response functions of superfluid neutron matter

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jochen; Sedrakian, Armen [Institut fuer Theoretische Physik, Goethe Universitaet, 60438 Frankfurt/Main (Germany)

    2011-07-01

    We investigate the response of pair-correlated neutron matter under conditions relevant to neutron stars to external weak probes and compute its neutrino emissivity in vector and axialvector channels. To derive the response functions we sum up an infinite chain of particle-hole ladder diagrams within finite-temperature Green's function theory. The polarization tensor of matter is evaluated in the limit of small momentum transfers. The calculated neutrino emission via the weak neutral current processes of pair-breaking and recombination of Cooper-pairs in neutron stars causes a cooling of their baryonic interior, and represents an important mechanism for the thermal evolution of the star within a certain time domain.

  3. Dark matter, neutron stars, and strange quark matter.

    Science.gov (United States)

    Perez-Garcia, M Angeles; Silk, Joseph; Stone, Jirina R

    2010-10-01

    We show that self-annihilating weakly interacting massive particle (WIMP) dark matter accreted onto neutron stars may provide a mechanism to seed compact objects with long-lived lumps of strange quark matter, or strangelets, for WIMP masses above a few GeV. This effect may trigger a conversion of most of the star into a strange star. We use an energy estimate for the long-lived strangelet based on the Fermi-gas model combined with the MIT bag model to set a new limit on the possible values of the WIMP mass that can be especially relevant for subdominant species of massive neutralinos.

  4. Neutron beams. Understanding and characterizing matter

    International Nuclear Information System (INIS)

    Pepy, G.

    2007-01-01

    This article treats of the numerous methods that use the undulatory properties of neutrons (their scattering in matter). Content: 1 - structure of crystallized matter: determination of a magnetic structure, hydrogen localization inside an alloy, 3D mapping of internal stresses inside materials, determination of the crystallographic structure, structure of a monocrystal by 4 circles diffraction; 2 - reflectometry, surface profiles: super-mirrors for neutron guides, giant magnetoresistance thin film devices; 3 - small angle scattering: protein and polyelectrolyte complexes, ropes integrity and microstructure, aggregates growth inside irradiated steels, microstructural evolution of defects inside race car engine pistons; 4 - dynamics: collective mode dynamics - three axis spectrometer, Mn Te magnons in thin film, scattering dynamics - quasi-elastic time-of-flight spectrometer, water diffusion inside cement. (J.S.)

  5. Neutron matter properties using generalized Skyrme force

    International Nuclear Information System (INIS)

    Mansour, H.M.M.; Ramadan, Kh.A.

    2002-01-01

    The generalized Skyrme potential is used to calculate the properties of neutron matter in the form of the Thomas–Fermi model. The binding energy per particle, spin symmetry energy, free energy, pressure, entropy, sound velocity and magnetic susceptibility are calculated as a function of density ρ. The results are comparable with those obtained by Friedman and Pandharipande, who used the Urbana v 14 potential plus an effective repulsive three-body force. (author)

  6. Hyperon-mixed neutron star matter and neutron stars

    International Nuclear Information System (INIS)

    Nishizaki, Shigeru; Takatsuka, Tatsuyuki; Yamamoto, Yasuo

    2002-01-01

    Effective Σ - n and Σ - Σ - interactions are derived from the G-matrix calculations for {n+Σ - } matter and employed in the investigation of hyperon mixing in neutron star matter. The threshold densities ρ t (Y) at which hyperons start to appear are between 2ρ 0 and 3ρ 0 (where ρ 0 is the normal nuclear density) for both Λ and Σ - , and their fractions increase rapidly with baryon density, reaching 10% already for ρ≅ρ t + ρ 0 . The mechanism of hyperon mixing and single-particle properties, such as the effective mass and the potential depth, are analyzed taking into account the roles of YN and NN interactions. The resulting equation of state is found to be too soft to sustain the observed neutron star mass M obs =1.44(solar mass). We discuss the reason for this and stress the necessity of the ''extra repulsion'' for YN and YY interactions to resolve this crucial problem. It is remarked that ρ t (Y) would be as large as 4ρ 0 for neutron stars compatible with M obs . A comment is given regarding the effects on the Y-mixing problem from a less attractive ΛΛ interaction, newly suggested by the NAGARA event. (author)

  7. Neutron matter, neutron pairing, and neutron drops based on chiral effective field theory interactions

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Thomas

    2016-10-19

    The physics of neutron-rich systems is of great interest in nuclear and astrophysics. Precise knowledge of the properties of neutron-rich nuclei is crucial for understanding the synthesis of heavy elements. Infinite neutron matter determines properties of neutron stars, a final stage of heavy stars after a core-collapse supernova. It also provides a unique theoretical laboratory for nuclear forces. Strong interactions are determined by quantum chromodynamics (QCD). However, QCD is non-perturbative at low energies and one presently cannot directly calculate nuclear forces from it. Chiral effective field theory circumvents these problems and connects the symmetries of QCD to nuclear interactions. It naturally and systematically includes many-nucleon forces and gives access to uncertainty estimates. We use chiral interactions throughout all calculation in this thesis. Neutron stars are very extreme objects. The densities in their interior greatly exceed those in nuclei. The exact composition and properties of neutron stars is still unclear but they consist mainly of neutrons. One can explore neutron stars theoretically with calculations of neutron matter. In the inner core of neutron stars exist very high densities and thus maybe exotic phases of matter. To investigate whether there exists a phase transition to such phases even at moderate densities we study the chiral condensate in neutron matter, the order parameter of chiral symmetry breaking, and find no evidence for a phase transition at nuclear densities. We also calculate the more extreme system of spin-polarised neutron matter. With this we address the question whether there exists such a polarised phase in neutron stars and also provide a benchmark system for lattice QCD. We find spin-polarised neutron matter to be an almost non-interacting Fermi gas. To understand the cooling of neutron stars neutron pairing is of great importance. Due to the high densities especially triplet pairing is of interest. We

  8. Phase transitions in nuclear matter and consequences for neutron stars

    International Nuclear Information System (INIS)

    Kaempfer, B.

    1983-04-01

    Estimates of the minimal bombarding energy necessary to reach the quark gluon phase in heavy ion collisions are presented within a hydrodynamical scenario. Further, the consequences of first-order phase transitions from nuclear/neutron matter to pion-condensed matter or quark matter are discussed for neutron stars. (author)

  9. Particulate matter and neutron activation analysis

    International Nuclear Information System (INIS)

    Otoshi, Tsunehiko

    2003-01-01

    In these years, economy of East Asian region is rapidly growing, and countries in this region are facing serious environmental problems. Neutron activation analysis is known as one of high-sensitive analytical method for multi elements. And it is a useful tool for environmental research, particularly for the study on atmospheric particulate matter that consists of various constituents. Elemental concentration represents status of air, such as emission of heavy metals from industries and municipal incinerators, transportation of soil derived elements more than thousands of kilometers, and so on. These monitoring data obtained by neutron activation analysis can be a cue to evaluate environment problems. Japanese government launched National Air Surveillance Network (NASN) employing neutron activation analysis in 1974, and the data has been accumulated at about twenty sampling sites. As a result of mitigation measure of air pollution sources, concentrations of elements that have anthropogenic sources decreased particularly at the beginning of the monitoring period. However, even now, concentrations of these anthropogenic elements reflect the characteristics of each sampling site, e.g. industrial/urban, rural, and remote. Soil derived elements have a seasonal variation because of the contribution of continental dust transported by strong westerly winds prevailing in winter and spring season. The health effects associated with trace elements in particulate matter have not been well characterized. However, there is increasing evidence that particulate air pollution, especially fine portion of particles in many different cities is associated with acute mortality. Neutron activation analysis is also expected to provide useful information to this new study field related to human exposures and health risk. (author)

  10. Hyperon-mixed neutron star matter and neutron stars

    CERN Document Server

    Nishizaki, S; Yamamoto, Y

    2002-01-01

    Effective SIGMA sup - n and SIGMA sup -SIGMA sup - interactions are derived from the G-matrix calculations for left brace n+SIGMA sup -right brace matter and employed in the investigation of hyperon mixing in neutron star matter. The threshold densities rho sub t (Y) at which hyperons start to appear are between 2 rho sub 0 and 3 rho sub 0 (where rho sub 0 is the normal nuclear density) for both LAMBDA and SIGMA sup - , and their fractions increase rapidly with baryon density, reaching 10% already for rho approx = rho sub t + rho sub 0. The mechanism of hyperon mixing and single-particle properties, such as the effective mass and the potential depth, are analyzed taking into account the roles of YN and NN interactions. The resulting equation of state is found to be too soft to sustain the observed neutron star mass M sub o sub b sub s =1.44(solar mass). We discuss the reason for this and stress the necessity of the ''extra repulsion'' for YN and YY interactions to resolve this crucial problem. It is remarked ...

  11. Physics of dense matter, neutron stars, and supernova

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1989-02-01

    Nuclear and astrophysical evidence on the equation of state of dense matter is examined. The role of hyperonization of matter in the development of proto-neutron stars is briefly discussed. 7 refs., 4 figs

  12. Λ, Σ, and Ξ hyperons in neutron matter

    International Nuclear Information System (INIS)

    Kohno, M.

    2013-01-01

    Hyperon single-particle potentials are calculated in pure neutron matter in the framework of the lowest-order Brueckner theory, using two recent baryon–baryon interactions, the SU 6 quark-model potential and the potential derived from the chiral effective field theory. These properties are important for understanding neutron star matter on the basis of underlying baryon–baryon interactions. Because the calculated potential of Σ − is strongly repulsive and that of Ξ − is also repulsive, these hyperons are unlikely to appear in neutron star matter. The Λ potential is attractive enough to appear in high neutron matter as has been commonly expected in microscopic calculations. After showing important contributions of three-nucleon forces in neutron matter, analogous repulsive contributions to the Λ potential from the Σ ⁎ excitation are estimated by evaluating second-order diagrams

  13. Neutron matter within QCD sum rules

    Science.gov (United States)

    Cai, Bao-Jun; Chen, Lie-Wen

    2018-05-01

    The equation of state (EOS) of pure neutron matter (PNM) is studied in QCD sum rules (QCDSRs ). It is found that the QCDSR results on the EOS of PNM are in good agreement with predictions by current advanced microscopic many-body theories. Moreover, the higher-order density terms in quark condensates are shown to be important to describe the empirical EOS of PNM in the density region around and above nuclear saturation density although they play a minor role at subsaturation densities. The chiral condensates in PNM are also studied, and our results indicate that the higher-order density terms in quark condensates, which are introduced to reasonably describe the empirical EOS of PNM at suprasaturation densities, tend to hinder the appearance of chiral symmetry restoration in PNM at high densities.

  14. Many-body theory of nuclear and neutron star matter

    Energy Technology Data Exchange (ETDEWEB)

    Pandharipande, V R; Akmal, A; Ravenhall, D G [Dept. of Physics, Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)

    1998-06-01

    We present results obtained for nuclei, nuclear and neutron star matter, and neutron star structure obtained with the recent Argonne v{sub 18} two- nucleon and Urbana IX three-nucleon interactions including relativistic boost corrections. These interactions predict that matter will undergo a transition to a spin layered phase with neutral pion condensation. We also consider the possibility of a transition to quark matter. (orig.)

  15. Many-body theory of nuclear and neutron star matter

    International Nuclear Information System (INIS)

    Pandharipande, V.R.; Akmal, A.; Ravenhall, D.G.

    1998-01-01

    We present results obtained for nuclei, nuclear and neutron star matter, and neutron star structure obtained with the recent Argonne v 18 two- nucleon and Urbana IX three-nucleon interactions including relativistic boost corrections. These interactions predict that matter will undergo a transition to a spin layered phase with neutral pion condensation. We also consider the possibility of a transition to quark matter. (orig.)

  16. Pion condensation in cold dense matter and neutron stars

    International Nuclear Information System (INIS)

    Haensel, P.; Proszynski, M.

    1982-01-01

    We study possible influence, on the neutron star structure, of a pion condensation occurring in cold dense matter. Several equations of state with pion-condensed phase are considered. The models of neutron stars are calculated and confronted with existing observational data on pulsars. Such a confrontation appears to rule out the models of dense matter with an abnormal self-bound state, and therefore it seems to exclude the possibility of the existence of abnormal superheavy neutron nuclei and abnormal neutron stars with a liquid pion-condensed surface

  17. On the capture of dark matter by neutron stars

    International Nuclear Information System (INIS)

    Güver, Tolga; Erkoca, Arif Emre; Sarcevic, Ina; Reno, Mary Hall

    2014-01-01

    We calculate the number of dark matter particles that a neutron star accumulates over its lifetime as it rotates around the center of a galaxy, when the dark matter particle is a self-interacting boson but does not self-annihilate. We take into account dark matter interactions with baryonic matter and the time evolution of the dark matter sphere as it collapses within the neutron star. We show that dark matter self-interactions play an important role in the rapid accumulation of dark matter in the core of the neutron star. We consider the possibility of determining an exclusion region of the parameter space for dark matter mass and dark matter interaction cross section with the nucleons as well as dark matter self-interaction cross section, based on the observation of old neutron stars. We show that for a dark matter density of 10 3 GeV/cm 3 and dark matter mass m χ ∼< 10 GeV, there is a potential exclusion region for dark matter interactions with nucleons that is three orders of magnitude more stringent than without self-interactions. The potential exclusion region for dark matter self-interaction cross sections is many orders of magnitude stronger than the current Bullet Cluster limit. For example, for high dark matter density regions, we find that for m χ ∼ 10 GeV when the dark matter interaction cross section with the nucleons ranges from σ χn ∼ 10 −52 cm 2 to σ χn ∼ 10 −57 cm 2 , the dark matter self-interaction cross section limit is σ χχ ∼< 10 −33 cm 2 , which is about ten orders of magnitude stronger than the Bullet Cluster limit

  18. High-Energy Neutron Backgrounds for Underground Dark Matter Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Syracuse Univ., NY (United States)

    2016-01-01

    Direct dark matter detection experiments usually have excellent capability to distinguish nuclear recoils, expected interactions with Weakly Interacting Massive Particle (WIMP) dark matter, and electronic recoils, so that they can efficiently reject background events such as gamma-rays and charged particles. However, both WIMPs and neutrons can induce nuclear recoils. Neutrons are then the most crucial background for direct dark matter detection. It is important to understand and account for all sources of neutron backgrounds when claiming a discovery of dark matter detection or reporting limits on the WIMP-nucleon cross section. One type of neutron background that is not well understood is the cosmogenic neutrons from muons interacting with the underground cavern rock and materials surrounding a dark matter detector. The Neutron Multiplicity Meter (NMM) is a water Cherenkov detector capable of measuring the cosmogenic neutron flux at the Soudan Underground Laboratory, which has an overburden of 2090 meters water equivalent. The NMM consists of two 2.2-tonne gadolinium-doped water tanks situated atop a 20-tonne lead target. It detects a high-energy (>~ 50 MeV) neutron via moderation and capture of the multiple secondary neutrons released when the former interacts in the lead target. The multiplicity of secondary neutrons for the high-energy neutron provides a benchmark for comparison to the current Monte Carlo predictions. Combining with the Monte Carlo simulation, the muon-induced high-energy neutron flux above 50 MeV is measured to be (1.3 ± 0.2) ~ 10-9 cm-2s-1, in reasonable agreement with the model prediction. The measured multiplicity spectrum agrees well with that of Monte Carlo simulation for multiplicity below 10, but shows an excess of approximately a factor of three over Monte Carlo prediction for multiplicities ~ 10 - 20. In an effort to reduce neutron backgrounds for the dark matter experiment SuperCDMS SNO- LAB, an active neutron veto was developed

  19. Condensed matter and materials research using neutron diffraction and spectroscopy: reactor and pulsed neutron sources

    International Nuclear Information System (INIS)

    Bisanti, Paola; Lovesey, S.W.

    1987-05-01

    The paper provides a short, and partial view of the neutron scattering technique applied to condensed matter and materials research. Reactor and accelerator-based neutron spectrometers are discussed, together with examples of research projects that illustrate the puissance and modern applications of neutron scattering. Some examples are chosen to show the range of facilities available at the medium flux reactor operated by Casaccia ENEA, Roma and the advanced, pulsed spallation neutron source at the Rutherford Appleton Laboratory, Oxfordshire. (author)

  20. Advanced spallation neutron sources for condensed matter research

    International Nuclear Information System (INIS)

    Lovesey, S.W.; Stirling, G.C.

    1984-03-01

    Advanced spallation neutron sources afford significant advantages over existing high flux reactors. The effective flux is much greater than that currently available with reactor sources. A ten-fold increase in neutron flux will be a major benefit to a wide range of condensed matter studies, and it will realise important experiments that are marginal at reactor sources. Moreover, the high intensity of epithermal neutrons open new vistas in studies of electronic states and molecular vibrations. (author)

  1. Self-energy dispersion effects on neutron matter superfluidity

    International Nuclear Information System (INIS)

    Zuo Wei

    2001-01-01

    The effects of the dispersion and ground state correlation of the single particle self-energy on neutron matter superfluidity have been investigated in the framework of the Extended Brueckner-Hartree-Fock and the generalized BCS approaches. A sizable reduction of the energy gap is found due to the energy dependence of the self-energy. And the inclusion of the ground state correlations in the self-energy suppresses further the neutron matter superfluidity

  2. Nuclear symmetry energy and stability of matter in neutron stars

    International Nuclear Information System (INIS)

    Kubis, Sebastian

    2007-01-01

    It is shown that the nuclear symmetry energy is the key quantity in the stability consideration in neutron star matter. The symmetry energy controls the position of crust-core transition and also may lead to new effects in the inner core of neutron star

  3. Limits on Self-Interacting Dark Matter from Neutron Stars

    DEFF Research Database (Denmark)

    Kouvaris, C.

    2012-01-01

    We impose new severe constraints on the self-interactions of fermionic asymmetric dark matter based on observations of nearby old neutron stars. Weakly interacting massive particle (WIMP) self-interactions mediated by Yukawa-type interactions can lower significantly the number of WIMPs necessary...... for gravitational collapse of the WIMP population accumulated in a neutron star. Even nearby neutron stars located at regions of low dark matter density can accrete a sufficient number of WIMPs that can potentially collapse, form a mini black hole, and destroy the host star. Based on this, we derive constraints...

  4. Neutron stars at the dark matter direct detection frontier

    Science.gov (United States)

    Raj, Nirmal; Tanedo, Philip; Yu, Hai-Bo

    2018-02-01

    Neutron stars capture dark matter efficiently. The kinetic energy transferred during capture heats old neutron stars in the local galactic halo to temperatures detectable by upcoming infrared telescopes. We derive the sensitivity of this probe in the framework of effective operators. For dark matter heavier than a GeV, we find that neutron star heating can set limits on the effective operator cutoff that are orders of magnitude stronger than possible from terrestrial direct detection experiments in the case of spin-dependent and velocity-suppressed scattering.

  5. Matter and Radiation in Strong Magnetic Fields of Neutron Stars

    International Nuclear Information System (INIS)

    Lai, D

    2006-01-01

    Neutron stars are found to possess magnetic fields ranging from 10 8 G to 10 15 G, much larger than achievable in terrestrial laboratories. Understanding the properties of matter and radiative transfer in strong magnetic fields is essential for the proper interpretation of various observations of magnetic neutron stars, including radio pulsars and magnetars. This paper reviews the atomic/molecular physics and condensed matter physics in strong magnetic fields, as well as recent works on modeling radiation from magnetized neutron star atmospheres/surface layers

  6. Can dark matter explain the braking index of neutron stars?

    DEFF Research Database (Denmark)

    Kouvaris, C.; Perez-Garcia, M. A.

    2014-01-01

    We explore a new mechanism of slowing down the rotation of neutron stars via accretion of millicharged dark matter. We find that this mechanism yields pulsar braking indices that can be substantially smaller than the standard n similar to 3 of the magnetic dipole radiation model for millicharged...... dark matter particles that are not excluded by existing experimental constraints thus accommodating existing observations....

  7. Recent Results on SUSY and Exotica Searches at the LHC

    CERN Document Server

    Grout, Zara Jane; The ATLAS collaboration

    2015-01-01

    A review is presented of searches for Beyond the Standard Model (BSM) physics at the ATLAS and CMS experiments at the Large Hadron Collider (LHC) with emphasis on most recent results. This includes a summary of Supersymmetry searches covering strong, electroweak, and R-parity violating scenarios, and a range of exotica searches including heavy boson searches, extra dimensions, and long-lived particles. The status of BSM physics after the first data-taking period (Run 1) of the LHC and the prospects for the second data-taking period (Run 2), beginning in 2015, are discussed.

  8. Recent Results on SUSY and Exotica Searches at the LHC

    Directory of Open Access Journals (Sweden)

    Grout Zara

    2015-01-01

    Full Text Available A review is presented of searches for Beyond the Standard Model (BSM physics at the ATLAS and CMS experiments at the Large Hadron Collider (LHC with emphasis on most recent results. This includes a summary of Supersymmetry searches covering strong, electroweak, and R-parity violating scenarios, and a range of exotica searches including heavy boson searches, extra dimensions, and long-lived particles. The status of BSM physics after the first data-taking period (Run 1 of the LHC and the prospects for the second data-taking period (Run 2, beginning in 2015, are discussed.

  9. Use of ultracold neutrons for condensed-matter studies

    Energy Technology Data Exchange (ETDEWEB)

    Michaudon, A.

    1997-05-01

    Ultracold neutrons have such low velocities that they are reflected by most materials at all incident angles and can be stored in material bottles for long periods of time during which their intrinsic properties can be studied in great detail. These features have been mainly used for fundamental-physics studies including the detection of a possible neutron electric dipole moment and the precise determination of neutron-decay properties. Ultracold neutrons can also play a role in condensed-matter studies with the help of high-resolution spectrometers that use gravity as a strongly dispersive medium for low-velocity neutrons. Such studies have so far been limited by the low intensity of existing ultracold-neutron sources but could be reconsidered with more intense sources, which are now envisaged. This report provides a broad survey of the properties of ultracold neutrons (including their reflectivity by different types of samples), of ultracold-neutron spectrometers that are compared with other high-resolution instruments, of results obtained in the field of condensed matter with these instruments, and of neutron microscopes. All these subjects are illustrated by numerous examples.

  10. Use of ultracold neutrons for condensed-matter studies

    International Nuclear Information System (INIS)

    Michaudon, A.

    1997-05-01

    Ultracold neutrons have such low velocities that they are reflected by most materials at all incident angles and can be stored in material bottles for long periods of time during which their intrinsic properties can be studied in great detail. These features have been mainly used for fundamental-physics studies including the detection of a possible neutron electric dipole moment and the precise determination of neutron-decay properties. Ultracold neutrons can also play a role in condensed-matter studies with the help of high-resolution spectrometers that use gravity as a strongly dispersive medium for low-velocity neutrons. Such studies have so far been limited by the low intensity of existing ultracold-neutron sources but could be reconsidered with more intense sources, which are now envisaged. This report provides a broad survey of the properties of ultracold neutrons (including their reflectivity by different types of samples), of ultracold-neutron spectrometers that are compared with other high-resolution instruments, of results obtained in the field of condensed matter with these instruments, and of neutron microscopes. All these subjects are illustrated by numerous examples

  11. Quark matter inside neutron stars in an effective chiral model

    International Nuclear Information System (INIS)

    Kotlorz, A.; Kutschera, M.

    1994-02-01

    An effective chiral model which describes properties of a single baryon predicts that the quark matter relevant to neutron stars, close to the deconfinement density, is in a chirally broken phase. We find the SU(2) model that pion-condensed up and down quark matter is preferred energetically at neutron star densities. It exhibits spin ordering and can posses a permanent magnetization. The equation of state of quark matter with chiral condensate is very well approximated by bag model equation of the state with suitably chosen parameters. We study quark cores inside neutron stars in this model using realistic nucleon equations of state. The biggest quark core corresponds to the second order phase transition to quark matter. Magnetic moment of the pion-condensed quark core is calculated. (author). 19 refs, 10 refs, 1 tab

  12. Effect of accelerated matter in neutron optics

    International Nuclear Information System (INIS)

    Frank, A. I.; Geltenbort, P.; Jentschel, M.; Kustov, D. V.; Kulin, G. V.; Nosov, V. G.; Strepetov, A. N.

    2008-01-01

    Results of experiments aimed at observing the change in the energy of a neutron traversing an accelerated refractive sample are reported. The experiments were performed with ultracold neutrons, the energy transfer in these experiments being ±(2-6) x 10 -10 eV. The results suggest the existence of the effect and agree with theoretical predictions to a precision higher than 10%. A similar effect was previously predicted for the change in the frequency of an electromagnetic wave traversing an accelerated dielectric slab. In all probability, the effect has a very general nature, but it is presently observed only in neutron optics.

  13. Condensed matter research using pulsed neutron sources: a bibliography

    International Nuclear Information System (INIS)

    Mildner, D.F.R.; Stirling, G.C.

    1976-05-01

    This report is an updated revision of RL-75-095 'Condensed Matter Research Using Pulsed Neutron Sources: A Bibliography'. As before, the survey lists published papers concerning (a) the production of high intensity neutron pulses suitable for thermal neutron scattering research, (b) moderating systems for neutron thermalization and pulse shaping, (c) techniques and instrumentation for diffraction and inelastic scattering at pulsed sources, and (d) their application to research problems concerning the structural and dynamical properties of condensed matter. Papers which deal with the white beam time-of-flight technique at steady state reactors have also been included. A number of scientists have brought to the author's attention papers which have been published since the previous edition. They are thanked and encouraged to continue the cooperation so that the bibliography may be updated periodically. (author)

  14. Dark Matter Interpretation of the Neutron Decay Anomaly.

    Science.gov (United States)

    Fornal, Bartosz; Grinstein, Benjamín

    2018-05-11

    There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

  15. Dark Matter Interpretation of the Neutron Decay Anomaly.

    OpenAIRE

    Fornal, B; Grinstein, B

    2018-01-01

    There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

  16. Neutron star matter equation of state: current status and challenges

    Science.gov (United States)

    Ohnishi, Akira

    2014-09-01

    Neutron star matter has a variety of constituents and structures depending on the density; neutron-rich nuclei surounded by electrons and drip neutrons in the crust, pasta nuclei at the bottom of inner crust, and uniform isospin-asymmetric nuclear matter in a superfluid state in the outer core. In the inner core, the neutron Fermi energy becomes so large that exotic constituents such as hyperons, mesons and quarks may emerge. Radioactive beam and hypernuclear experiments provide information on the symmetry energy and superfluidity in the crust and outer core and on the hyperon potentials in the inner core, respectively. Cold atom experiments are also helpful to understand pure neutron matter, which may be simulated by the unitary gas. An equation of state (EOS) constructed based on these laboratory experiments has to be verified by the astronomical observations such as the mass, radius, and oscillations of neutron stars. One of the key but missing ingredients is the three-baryon interactions such as the hyperon-hyperon-nucleon (YYN) interaction. YYN interaction is important in order to explain the recently discovered massive neutron stars consistently with laboratory experiments. We have recently found that the ΛΛ interaction extracted from the ΛΛ correlation at RHIC is somewhat stronger than that from double Λ hypernuclei. Since these two interactions corresponds to the vacuum and in-medium ΛΛ interactions, respectively, the difference may tell us a possible way to access the YYN interaction based on experimental data. In the presentation, after a review on the current status of neutron star matter EOS studies, we discuss the necessary tasks to pin down the EOS. We also present our recent study of ΛΛ interaction from correlation data at RHIC.

  17. Dark Matter Interpretation of the Neutron Decay Anomaly

    OpenAIRE

    Fornal, Bartosz; Grinstein, Benjamín

    2018-01-01

    There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

  18. Dark Matter Interpretation of the Neutron Decay Anomaly

    Science.gov (United States)

    Fornal, Bartosz; Grinstein, Benjamín

    2018-05-01

    There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

  19. Phase transitions in neutron matter and dynamics of neutron stars

    International Nuclear Information System (INIS)

    Migdal, A.B.; Chernoutsan, A.I.; Mishustin, I.N.

    1980-01-01

    The neutron star dynamics during the formation of the superdense core is considered, and the instability conditions with respect to this formation are described. Within the framework of a simple model the equation of motion of the superdense core radius is investigated, its solutions in a simple model are found analytically for some limiting cases, and the results of numerical solution of the equation of motion are presented. The possible ways for the envelope to be blown off are considered

  20. Nuclear matter in neutron star crust

    International Nuclear Information System (INIS)

    Kido, Toshihiko; Maruyama, Toshiki; Chiba, Satoshi; Niita, Koji

    2000-01-01

    Properties of nuclear matter below the nuclear saturation density is analyzed by numerical simulations with the periodic boundary condition. The equation of state at these densities is softened by the formation of cluster(s) internal density of which is nearly equal to the saturation density. The structure of nuclear matter shows some exotic shapes with variation of the density. Furthermore, it is found that the symmetry parameter a sym (ρ) is not a linear function of density at low density region. (author)

  1. Magnetization of dense neutron matter in a strong magnetic field

    International Nuclear Information System (INIS)

    Isaev, A.A.; Yang, J.

    2010-01-01

    Spin polarized states in neutron matter at a strong magnetic field up to 1018 G are considered in the model with the Skyrme effective interaction. Analyzing the self consistent equations at zero temperature, it is shown that a thermodynamically stable branch of solutions for the spin polarization parameter as a function of the density corresponds to the negative spin polarization when the majority of neutron spins are oriented oppositely to the direction of the magnetic field. In addition, beginning from some threshold density dependent on the magnetic field strength, the self-consistent equations have also two other branches of solutions for the spin polarization parameter with the positive spin polarization. The free energy corresponding to one of these branches turns out to be very close to the free energy corresponding to the thermodynamically preferable branch with the negative spin polarization. As a consequence, at a strong magnetic field, the state with the positive spin polarization can be realized as a metastable state at the high density region in neutron matter which changes into a thermodynamically stable state with the negative spin polarization with decrease in the density at some threshold value. The calculations of the neutron spin polarization parameter, energy per neutron, and chemical potentials of spin-up and spin-down neutrons as functions of the magnetic field strength show that the influence of the magnetic field remains small at the field strengths up to 1017 G.

  2. Neutron stars as probes of extreme energy density matter

    Indian Academy of Sciences (India)

    2015-05-07

    May 7, 2015 ... Neutron stars have long been regarded as extraterrestrial laboratories from which we can learn about extreme energy density matter at low temperatures. In this article, some of the recent advances made in astrophysical observations and related theory are highlighted. Although the focus is on the much ...

  3. Neutron stars as probes of extreme energy density matter

    Indian Academy of Sciences (India)

    2015-05-07

    May 7, 2015 ... and the orbital period decay due to the emission of gravitational radiation. ˙P = −. 192π ... masses severely restrict the EoS of neutron star matter. Masses ..... (9) Is unstable burning of carbon (C) the real cause of superbursts?

  4. Proton impurity in the neutron matter: a nuclear polaron problem

    Energy Technology Data Exchange (ETDEWEB)

    Kutschera, M [Institute of Nuclear Physics, Cracow (Poland); Wojcik, W [Politechnika Krakowska, Cracow (Poland)

    1992-10-01

    We study interactions of a proton impurity with density oscillations of the neutron matter in a Debye approximation. The proton-phonon coupling is of the deformation-potential type at long wavelengths. It is weak at low density and increases with the neutron matter density. We calculate the proton`s effective mass perturbatively for a weak coupling, and use a canonical transformation technique for stronger couplings. The proton`s effective mass grows significantly with density, and at higher densities the proton impurity can be localized. This behaviour is similar to that of the polaron in solids. We obtain properties of the localized proton in the strong coupling regime from variational calculations, treating the neutron in the Thomas-Fermi approximation. (author). 14 refs, 8 figs.

  5. Neutron scattering in soft matter physics and chemistry

    International Nuclear Information System (INIS)

    White, J.W.

    1999-01-01

    Recent experiments area of soft matter science show that self assembly on the micron scale as well as the nanometer scale can be directed chemically. This lecture illustrates how such processes can be studied using the contrast variation available in neutron scattering through isotopic replacement and the techniques of neutron small angle scattering and neutron reflectivity. Related dynamical information at nanometer resolution and on time scales between a nanosecond and a few tenths of a picosecond will become accessible with brighter neutron sources. The examples presented concern the template induced crystallisation of zeolites, the liquid crystal template induced synthesis of mesoporous materials and the structure of thin films at the air water interface. (J.P.N.)

  6. Observational Constraints on Quark Matter in Neutron Stars

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We study the observational constraints of mass and redshift on the properties of the equation of state (EOS) for quark matter in compact stars based on the quasi-particle description. We discuss two scenarios: strange stars and hybrid stars. We construct the equations of state utilizing an extended MIT bag model taking the medium effect into account for quark matter and the relativistic mean field theory for hadron matter. We show that quark matter may exist in strange stars and in the interior of neutron stars. The bag constant is a key parameter that affects strongly the mass of strange stars. The medium effect can lead to the stiffer hybrid-star EOS approaching the pure hadronic EOS, due to the reduction of quark matter, and hence the existence of heavy hybrid stars. We find that a middle range coupling constant may be the best choice for the hybrid stars being compatible with the observational constraints.

  7. Neutron matter with a model interaction

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Shaginyan, V.R.

    2000-01-01

    An infinite system of neutrons interacting by a model pair potential is considered. We investigate a case when this potential is sufficiently strong attractive, so that its scattering length a tends to infinity, a →-∞. It appeared, that if the structure of the potential is simple enough, including no finite parameters, reliable evidences can be presented that such a system is completely unstable at any finite density. The incompressibility as a function of the density is negative, reaching zero value when the density tends to zero. If the potential contains a sufficiently strong repulsive core then the system possesses an equilibrium density. The main features of a theory describing such systems are considered. (orig.)

  8. Neutron matter with a model interaction

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya. [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; A.F. Ioffe Physical-Technical Institute, 194021 St. Petersburg (Russian Federation); Shaginyan, V.R. [Petersburg Institute of Nuclear Physics, 188350 Gatchina (Russian Federation); Department of Physics, University of Washington, Seattle, WA 98195 (United States)

    2000-05-01

    An infinite system of neutrons interacting by a model pair potential is considered. We investigate a case when this potential is sufficiently strong attractive, so that its scattering length a tends to infinity, a {yields}-{infinity}. It appeared, that if the structure of the potential is simple enough, including no finite parameters, reliable evidences can be presented that such a system is completely unstable at any finite density. The incompressibility as a function of the density is negative, reaching zero value when the density tends to zero. If the potential contains a sufficiently strong repulsive core then the system possesses an equilibrium density. The main features of a theory describing such systems are considered. (orig.)

  9. Bookshelf (''Neutrons, Nuclei and Matter'', by J. Byrne)

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, P. G.

    1994-09-15

    Time was when a neophyte wanting to do experiments with neutrons would be told first to read D.J. Hughes' classic ''Pile Neutron Research'' (1952). The book by J. Byrne is in many respects a modern equivalent, although if you were to send your student away with it, you will risk not seeing him or her again for a considerable time. What is immediately striking is that the book, rich in information and quite long, is cross-disciplinary and touches essentially all the main areas of modern physics. It covers parts of particle physics, such as the internal structure of the neutron, time-reversal violation as revealed by the (still hypothetical) electric dipole moment of the neutron, and the coupling constants for the weak interaction. From the field of basic quantum physics there are chapters on neutron optics, wave phenomena with neutrons and on the applications of these in solid-state physics. Other chapters again delve deeply into nuclear structure, nuclear reaction theory, as well as their applications: nuclear reactors and nuclear energy. At a time with specialization rampant and many physicists tending to believe that venturing outside their own cloisters is uninteresting and even dangerous, it is a pleasure to come across a book that is basically just about physics. J. Byrne of Sussex has for long been active in neutron research at the British-French-German Institut Laue-Langevin (ILL) research reactor in Grenoble, where he has worked on subjects such as weak interactions and fundamental symmetries. He has clearly intended ''Neutrons, Nuclei and Matter'' as a vade-mecum that will allow the practitioner to find the necessary information and formulas. But I believe that many others not directly engaged in neutron research will gain new insight from its many examples. To take just one case, I had not been aware of the simple physical principles that permit cold neutrons to be stored in a bottle. (The main point is that a medium containing nuclei with positive

  10. Exploring matter with neutrons. highlights in research at the ILL

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    Neutrons are excellent probes of all kinds of matter. They are more penetrating than X-rays and provide complementary information on structure and dynamics. There are many variations of the neutron scattering process which gives the technique its wide applicability to many kinds of materials. This report briefly reviews the latest uses of this technique applied to: (i) Biology (cellulose, biological membranes and lipid membranes), (ii) Soft matter (ultrathin polymer films, the flowing of detergents and pastes), (iii) Liquids and glasses (glass transition, sound propagation in water), (iv) Chemistry and structure (the many phases of water), (v) Materials (alloys, helium bubbles in steel), (vi) Thin films (magnetic spirals in very thin films, giant magnetoresistance), (vii) Magnetism (molecular magnets, magnetic phase transitions, glassy magnets), and (viii) superfluid helium in porous media. (A.C.)

  11. Exploring matter with neutrons. highlights in research at the ILL

    International Nuclear Information System (INIS)

    2000-01-01

    Neutrons are excellent probes of all kinds of matter. They are more penetrating than X-rays and provide complementary information on structure and dynamics. There are many variations of the neutron scattering process which gives the technique its wide applicability to many kinds of materials. This report briefly reviews the latest uses of this technique applied to: i) Biology (cellulose, biological membranes and lipid membranes), ii) Soft matter (ultrathin polymer films, the flowing of detergents and pastes), iii) Liquids and glasses (glass transition, sound propagation in water), iv) Chemistry and structure (the many phases of water), v) Materials (alloys, helium bubbles in steel), vi) Thin films (magnetic spirals in very thin films, giant magnetoresistance), vii) Magnetism (molecular magnets, magnetic phase transitions, glassy magnets), and viii) superfluid helium in porous media. (A.C.)

  12. Proton mixing in -condensed phase of neutron star matter

    Energy Technology Data Exchange (ETDEWEB)

    Takatsuka, Tatsuyuki

    1984-08-01

    The mixing of protons in neutron star matter under the occurrence of condensation is studied in the framework of the ALS (Alternating Layer Spin) model and with the effective interaction approach. It is found that protons are likely to mix under the situation and cause a remarkable energy gain from neutron matter as the density increases. The extent of proton mixing becomes larger by about a factor (1.5-2.5) according to the density rho asymptotically equals (2-5)rho0, rho0 being the nuclear density, as compared with that for the case without pion condensation. The reason can be attributed to the two-dimensional nature of the Fermi gas state characteristic of the nucleon system under condensation.

  13. Pure Neutron Matter Constraints and Nuclear Symmetry Energy

    International Nuclear Information System (INIS)

    Fattoyev, F J; Newton, W G; Xu, Jun; Li, Bao-An

    2013-01-01

    In this review, we will discuss the results of our recent work [1] to study the general optimization of the pure isovector parameters of the popular relativistic mean-field (RMF) and Skyrme-Hartree-Fock (SHF) nuclear energy-density functionals (EDFs), using constraints on the pure neutron matter (PNM) equation of state (EoS) from recent ab initio calculations. By using RMF and SHF parameterizations that give equivalent predictions for ground-state properties of doubly magic nuclei and properties of symmetric nuclear matter (SNM) and PNM, we found that such optimization leads to broadly consistent symmetry energy J and its slope parameter L at saturation density within a tight range of α(J) sym , (b) the symmetry energy at supra-saturation densities, and (c) the radius of neutron stars.

  14. Naturalness in an Effective Field Theory for Neutron Star Matter

    International Nuclear Information System (INIS)

    Razeira, Moises; Vasconcellos, Cesar A.Z.; Bodmann, Bardo E.J.; Coelho, Helio T.; Dillig, Manfred

    2004-01-01

    High density hadronic matter is studied in a generalized relativistic multi-baryon lagrangian density. By comparing the predictions of our model with estimates obtained within a phenomenological naive dimensional analysis based on the naturalness of the coefficients of the theory, we show that naturalness plays a major role in effective field theory and, in combination with experiment, could represent a relevant criterium to select a model among others in the description of global static properties of neutron stars

  15. Model of superdense matter and its application to neutron stars

    International Nuclear Information System (INIS)

    Pedico, R.D.

    1976-01-01

    A phenomenological model of superdense baryonic matter at zero temperature is developed and the resulting equation of state is employed in the calculation of neutron star masses and moments of inertia. The strong interactions between the baryons are described by couplings to one scalar and one vector field. These fields are not identified with observed mesons. Only a particular class of diagrams, constructed from tadpole terms, is retained in this investigation. It is argued that these terms contain the leading order density dependence of any set of diagrams that can be built up from fundamental two baryon-one meson vertices. The two parameters in the model, the coupling strengths, are fixed by the requirement that the accepted binding energy of infinite nuclear matter be reproduced at nuclear density. These couplings are used to calculate a forward proton-neutron cross section, which is found to agree with experimental data over a limited energy range. A pressure-energy density equation of state is generated for an electrically neutral system of electrons, muons, and the lowest mass baryon octet. The constituents are held in chemical equilibrium by the weak interactions. The equation of state exhibits a broad phase transition encompassing nuclear density, which leads to neutron stars containing a nearly incompressible core surrounded by a significantly less dense shell. The masses and moments of inertia of these model neutron stars are in good agreement with observational data for pulsars

  16. Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

    Science.gov (United States)

    Mohapatra, Rabindra N.; Nussinov, Shmuel

    2018-01-01

    The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n -n‧ mixing parameter δ and n -n‧ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ ≤ 2 ×10-27 GeV and Δ ≤10-24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.

  17. Ultra-dense neutron star matter, strange quark stars, and the nuclear equation of state

    International Nuclear Information System (INIS)

    Weber, F.; Meixner, M.; Negreiros, R.P.; Malheiro, M.

    2007-01-01

    With central densities way above the density of atomic nuclei, neutron stars contain matter in one of the densest forms found in the universe. Depending of the density reached in the cores of neutron stars, they may contain stable phases of exotic matter found nowhere else in space. This article gives a brief overview of the phases of ultra-dense matter predicted to exist deep inside neutron stars and discusses the equation of state (EoS) associated with such matter. (author)

  18. Larvicidal activity of Lawsonia inermis and Murraya exotica leaves extract on filarial vector, Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    K. Dass

    2014-06-01

    Full Text Available Extensive use of synthetic and chemical insecticides to control mosquitoes result in environment hazards and development of resistance in vector species. This research work is about an alternative mosquito control method that is considered as safe to environment and non-target species and also bio-degradable. Hence an attempt was made to study the larvicidal effect of the extract of Lawsonia inermis and Murraya exotica leaves on III and IV instar larva and pupa of Culex quinquefasciatus. The LC50 value of Murraya exotica for III and IV instar larvae and pupae is 135.539 ppm, 154.361 ppm and 178.571 ppm respectively. Likewise for Lawsonia inermis it is 139.057 for III instar, 163.630 for IV instar and 188.151 for the pupa. Of these, two plants Murraya exotica plant extract is more effective than the Lawsonia inermis.

  19. Spin-polarized neutron matter at different orders of chiral effective field theory

    OpenAIRE

    Sammarruca, F.; Machleidt, R.; Kaiser, N.

    2015-01-01

    Spin-polarized neutron matter is studied using chiral two- and three-body forces. We focus, in particular, on predictions of the energy per particle in ferromagnetic neutron matter at different orders of chiral effective field theory and for different choices of the resolution scale. We discuss the convergence pattern of the predictions and their cutoff dependence. We explore to which extent fully polarized neutron matter behaves (nearly) like a free Fermi gas. We also consider the more gener...

  20. Evolution of newborn neutron stars: role of quark matter nucleation

    International Nuclear Information System (INIS)

    Bombaci, Ignazio; Logoteta, Domenico; Providencia, Constança; Vidaña, Isaac

    2011-01-01

    A phase of strong interacting matter with deconfined quarks is expected in the core of massive neutron stars. We study the quark deconfinement phase transition in cold (T = 0) and hot β-stable hadronic matter. Assuming a first order phase transition, we calculate and compare the nucleation rate and the nucleation time due to thermal and quantum nucleation mechanisms. We show that above a threshold value of the central pressure a pure hadronic star (HS) is metastable to the conversion to a quark star (QS) (i.e. hybrid star or strange star). We introduce the concept of critical mass M cr for cold HSs and proto-hadronic stars (PHSs), and the concept of limiting conversion temperature for PHSs. We show that PHSs with a mass M cr could survive the early stages of their evolution without decaying to QSs. Finally, we discuss the possible evolutionary paths of proto-hadronic stars.

  1. Finite size effects in neutron star and nuclear matter simulations

    Energy Technology Data Exchange (ETDEWEB)

    Giménez Molinelli, P.A., E-mail: pagm@df.uba.ar; Dorso, C.O.

    2015-01-15

    In this work we study molecular dynamics simulations of symmetric nuclear and neutron star matter using a semi-classical nucleon interaction model. Our aim is to gain insight on the nature of the so-called “finite size effects”, unavoidable in this kind of simulations, and to understand what they actually affect. To do so, we explore different geometries for the periodic boundary conditions imposed on the simulation cell: cube, hexagonal prism and truncated octahedron. For nuclear matter simulations we show that, at sub-saturation densities and low temperatures, the solutions are non-homogeneous structures reminiscent of the “nuclear pasta” phases expected in neutron star matter simulations, but only one structure per cell and shaped by specific artificial aspects of the simulations—for the same physical conditions (i.e. number density and temperature) different cells yield different solutions. The particular shape of the solution at low enough temperature and a given density can be predicted analytically by surface minimization. We also show that even if this behavior is due to the imposition of periodic boundary conditions on finite systems, this does not mean that it vanishes for very large systems, and it is actually independent of the system size. We conclude that, for nuclear matter simulations, the cells' size sets the only characteristic length scale for the inhomogeneities, and the geometry of the periodic cell determines the shape of those inhomogeneities. To model neutron star matter we add a screened Coulomb interaction between protons, and perform simulations in the three cell geometries. Our simulations indeed produce the well known nuclear pasta, with (in most cases) several structures per cell. However, we find that for systems not too large results are affected by finite size in different ways depending on the geometry of the cell. In particular, at the same certain physical conditions and system size, the hexagonal prism yields a

  2. Chemical Composition and Toxicity against Sitophilus zeamais and Tribolium castaneum of the Essential Oil of Murraya exotica Aerial Parts

    Directory of Open Access Journals (Sweden)

    Zhi Long Liu

    2010-08-01

    Full Text Available In our screening program for new agrochemicals from Chinese medicinal herbs, Murraya exotica was found to possess insecticidal activity against the maize weevil, Sitophilus zeamais and red flour beetle, Tribolium castaneum. The essential oil of aerial parts of M. exotica was obtained by hydrodistillation and investigated by GC and GC-MS. The main components of M. exotica essential oil were spathulenol (17.7%, a-pinene (13.3%, caryophyllene oxide (8.6%, and a-caryophyllene (7.3%. Essential oil of M. exotica possessed fumigant toxicity against S. zeamais and T. castaneum adults with LC50 values of 8.29 and 6.84 mg/L, respectively. The essential oils also show contact toxicity against S. zeamais and T. castaneum adults with LD50 values of 11.41 and 20.94 mg/adult, respectively.

  3. Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

    Directory of Open Access Journals (Sweden)

    Rabindra N. Mohapatra

    2018-01-01

    Full Text Available The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n−n′ mixing parameter δ and n−n′ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ≤2×10−27 GeV and Δ≤10−24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.

  4. Search for dark matter effects on gravitational signals from neutron star mergers

    Science.gov (United States)

    Ellis, John; Hektor, Andi; Hütsi, Gert; Kannike, Kristjan; Marzola, Luca; Raidal, Martti; Vaskonen, Ville

    2018-06-01

    Motivated by the recent detection of the gravitational wave signal emitted by a binary neutron star merger, we analyse the possible impact of dark matter on such signals. We show that dark matter cores in merging neutron stars may yield an observable supplementary peak in the gravitational wave power spectral density following the merger, which could be distinguished from the features produced by the neutron components.

  5. arXiv Search for Dark Matter Effects on Gravitational Signals from Neutron Star Mergers

    CERN Document Server

    Ellis, John; Hütsi, Gert; Kannike, Kristjan; Marzola, Luca; Raidal, Martti; Vaskonen, Ville

    2018-06-10

    Motivated by the recent detection of the gravitational wave signal emitted by a binary neutron star merger, we analyse the possible impact of dark matter on such signals. We show that dark matter cores in merging neutron stars may yield an observable supplementary peak in the gravitational wave power spectral density following the merger, which could be distinguished from the features produced by the neutron components.

  6. Search for dark matter effects on gravitational signals from neutron star mergers

    OpenAIRE

    Ellis, John; Hektor, Andi; Hütsi, Gert; Kannike, Kristjan; Marzola, Luca; Raidal, Martti; Vaskonen, Ville

    2018-01-01

    Motivated by the recent detection of the gravitational wave signal emitted by a binary neutron star merger, we analyse the possible impact of dark matter on such signals. We show that dark matter cores in merging neutron stars may yield an observable supplementary peak in the gravitational wave power spectral density following the merger, which could be distinguished from the features produced by the neutron components.

  7. arXiv Dark Matter Effects On Neutron Star Properties

    CERN Document Server

    Ellis, John; Kannike, Kristjan; Marzola, Luca; Raidal, Martti; Vaskonen, Ville

    2018-06-14

    We study possible effects of a dark matter (DM) core on the maximum mass of a neutron star (NS), on the mass-radius relation and on the NS tidal deformability parameter $\\Lambda$. We show that all these quantities would in general be reduced in the presence of a DM core. In particular, our calculations indicate that the presence of a DM core with a mass fraction $\\sim 5\\%$ could affect significantly the interpretation of these NS data as constraints on the nuclear equation of state (EOS), potentially excluding some EOS models on the basis of the measured mass of PSR J0348+0432, while allowing other EOS models to become consistent with the LIGO/Virgo upper limit on $\\Lambda$. Specific scenarios for generating such DM cores are explored in an Appendix.

  8. Falsification of Leggett's model using neutron matter waves

    International Nuclear Information System (INIS)

    Hasegawa, Yuji; Sponar, Stephan; Durstberger-Rennhofer, Katharina; Badurek, Gerald; Schmitzer, Claus; Bartosik, Hannes; Klepp, Jürgen

    2012-01-01

    According to Bell's theorem, no theory based on the joint assumption of realism and locality can reproduce certain predictions of quantum mechanics. Another class of realistic models, proposed by Leggett, that demands realism but abandons reliance on locality, is predicted to be in conflict with quantum mechanics. In this paper, we report on an experimental test of a contextual realistic model analogous to the model of Leggett performed with matter waves, more precisely with neutrons. Correlation measurements of the spin-energy entangled single-particle system show violation of a Leggett-type inequality by more than 7.6 standard deviations. Our experimental data falsify the contextual realistic model and are fully in favor of quantum mechanics. (paper)

  9. Three-Nucleon Forces and Triplet Pairing in Neutron Matter

    Science.gov (United States)

    Papakonstantinou, P.; Clark, J. W.

    2017-12-01

    The existence of superfluidity of the neutron component in the core of a neutron star, associated specifically with triplet P-wave pairing, is currently an open question that is central to interpretation of the observed cooling curves and other neutron-star observables. Ab initio theoretical calculations aimed at resolving this issue face unique challenges in the relevant high-density domain, which reaches beyond the saturation density of symmetrical nuclear matter. These issues include uncertainties in the three-nucleon (3N) interaction and in the effects of strong short-range correlations—and more generally of in-medium modification of nucleonic self-energies and interactions. A survey of existing solutions of the gap equations in the triplet channel demonstrates that the net impact on the gap magnitude of 3N forces, coupled channels, and mass renormalization shows extreme variation dependent on specific theoretical inputs, in some cases even pointing to the absence of a triplet gap, thus motivating a detailed analysis of competing effects within a well-controlled model. In the present study, we track the effects of the 3N force and in-medium modifications in the representative case of the ^3P_2 channel, based on the Argonne v_{18} two-nucleon (2N) interaction supplemented by 3N interactions of the Urbana IX family. Sensitivity of the results to the input interaction is clearly demonstrated. We point out consistency issues with respect to the simultaneous treatment of 3N forces and in-medium effects, which warrant further investigation. We consider this pilot study as the first step toward a systematic and comprehensive exploration of coupled-channel ^3P F_2 pairing using a broad range of 2N and 3N interactions from the current generation of refined semi-phenomenological models and models derived from chiral effective field theory.

  10. Inelastic and quasielastic neutron scattering studies on soft matter and biomolecules

    International Nuclear Information System (INIS)

    Kanaya, Toshiji

    2015-01-01

    Some characteristic features of soft matter and biomolecules in the inelastic and quasielastic neutron scattering (INS and QENS) studies are described. In order to clarify the current situation of the studies the research history on soft matter and biomolecules by INS and QENS are described. As examples of the studies of slow dynamics of soft matter, neutron spin echo studies on breathing mode of polymer micelle and static and dynamics fluctuations in polymer gels. (author)

  11. Searching for dark matter with neutron star mergers and quiet kilonovae

    Science.gov (United States)

    Bramante, Joseph; Linden, Tim; Tsai, Yu-Dai

    2018-03-01

    We identify new astrophysical signatures of dark matter that implodes neutron stars (NSs), which could decisively test whether NS-imploding dark matter is responsible for missing pulsars in the Milky Way galactic center, the source of some r -process elements, and the origin of fast-radio bursts. First, NS-imploding dark matter forms ˜10-10 solar mass or smaller black holes inside neutron stars, which proceed to convert neutron stars into ˜1.5 solar mass black holes (BHs). This decreases the number of neutron star mergers seen by LIGO/Virgo (LV) and associated merger kilonovae seen by telescopes like DES, BlackGEM, and ZTF, instead producing a population of "black mergers" containing ˜1.5 solar mass black holes. Second, dark matter-induced neutron star implosions may create a new kind of kilonovae that lacks a detectable, accompanying gravitational signal, which we call "quiet kilonovae." Using DES data and the Milky Way's r-process abundance, we constrain quiet kilonovae. Third, the spatial distribution of neutron star merger kilonovae and quiet kilonovae in galaxies can be used to detect dark matter. NS-imploding dark matter destroys most neutron stars at the centers of disc galaxies, so that neutron star merger kilonovae would appear mostly in a donut at large radii. We find that as few as ten neutron star merger kilonova events, located to ˜1 kpc precision could validate or exclude dark matter-induced neutron star implosions at 2 σ confidence, exploring dark matter-nucleon cross-sections 4-10 orders of magnitude below current direct detection experimental limits. Similarly, NS-imploding dark matter as the source of fast radio bursts can be tested at 2 σ confidence once 20 bursts are located in host galaxies by radio arrays like CHIME and HIRAX.

  12. Cardioacceleratory Neurons of the Isopod Crustacean, Ligia exotica : Visualization of Peripheral Projection onto the Heart Muscle

    OpenAIRE

    Akira, Sakurai; Hiroshi, Yamagishi; Institute of Biological Sciences, University of Tsukuba; Institute of Biological Sciences, University of Tsukuba

    1998-01-01

    Innervation of the heart muscle by the cardioacceleratory neurons was morphologically and electrophysiologically examined in the isopod crustacean, Ligia exotica. Intracellular injection of neurobiotin into the first and second cardioacceleratory neurons(CA1 and CA2)revealed their peripheral axonal projections. Inside the heart, the CA1 and CA2 axons ran along the trunk of the cardiac ganglion. Finely arborized branches with many varicosities arose from the axon and projected over the heart m...

  13. Out of Asia: mitochondrial evolutionary history of the globally introduced supralittoral isopod Ligia exotica.

    Science.gov (United States)

    Hurtado, Luis A; Mateos, Mariana; Wang, Chang; Santamaria, Carlos A; Jung, Jongwoo; Khalaji-Pirbalouty, Valiallah; Kim, Won

    2018-01-01

    The native ranges and invasion histories of many marine species remain elusive due to a dynamic dispersal process via marine vessels. Molecular markers can aid in identification of native ranges and elucidation of the introduction and establishment process. The supralittoral isopod Ligia exotica has a wide tropical and subtropical distribution, frequently found in harbors and ports around the globe. This isopod is hypothesized to have an Old World origin, from where it was unintentionally introduced to other regions via wooden ships and solid ballast. Its native range, however, remains uncertain. Recent molecular studies uncovered the presence of two highly divergent lineages of L. exotica in East Asia, and suggest this region is a source of nonindigenous populations. In this study, we conducted phylogenetic analyses (Maximum Likelihood and Bayesian) of a fragment of the mitochondrial 16S ribosomal (r)DNA gene using a dataset of this isopod that greatly expanded previous representation from Asia and putative nonindigenous populations around the world. For a subset of samples, sequences of 12S rDNA and NaK were also obtained and analyzed together with 16S rDNA. Our results show that L. exotica is comprised of several highly divergent genetic lineages, which probably represent different species. Most of the 16S rDNA genetic diversity (48 haplotypes) was detected in East and Southeast Asia. Only seven haplotypes were observed outside this region (in the Americas, Hawai'i, Africa and India), which were identical or closely related to haplotypes found in East and Southeast Asia. Phylogenetic patterns indicate the L. exotica clade originated and diversified in East and Southeast Asia, and only members of one of the divergent lineages have spread out of this region, recently, suggesting the potential to become invasive is phylogenetically constrained.

  14. Skyrme interaction and the properties of cold and hot neutron matter

    International Nuclear Information System (INIS)

    Mansour, H.M.M.; Hassan, M.Y.M.; Ramadan, S.

    1986-08-01

    The binding energy per particle, effective mass, magnetic susceptibility, etc for neutron matter are calculated using the Skyrme interaction SKII. Relativistic corrections to the non-relativistic Skyrme effective interaction to order 1/C 2 are also used to calculate the corrections for the binding energy of neutron matter. The correction is very small for small values of k h and increases as k n is increased. The thermal properties of neutron matter are calculated also using SKII force. The temperature dependences of the volume and spin pressure are determined. The results obtained show a similar trend as previous theoretical estimates by different methods of calculation. (author)

  15. The effect of the scalar-isovector meson field on hyperon-rich neutron star matter

    International Nuclear Information System (INIS)

    Mi, Aijun; Zuo, Wei; Li, Ang

    2008-01-01

    We investigate the effect of the scalar-isovector δ-meson field on the equation of state (EOS) and composition of hyperonic neutron star matter, and the properties of hyperonic neutron stars within the framework of the relativistic mean field theory. The influence of the δ-field turns out to be quite different and generally weaker for hyperonic neutron star matter as compared to that for npeμ neutron star matter. We find that inclusion of the δ-field enhances the strangeness content slightly and consequently moderately softens the EOS of neutron star matter in its hyperonic phase. As for the composition of hyperonic star matter, the effect of the δ-field is shown to shift the onset of the negatively-charged (positively-charged) hyperons to slightly lower (higher) densities and to enhance (reduce) their abundances. The influence of the δ-field on the maximum mass of hyperonic neutron stars is found to be fairly weak, whereas inclusion of the δ-field turns out to enhance sizably both the radii and the moments of inertia of neutron stars with given masses. It is also shown that the effects of the δ-field on the properties of hyperonic neutron stars remain similar in the case of switching off the Σ hyperons. (author)

  16. High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter

    International Nuclear Information System (INIS)

    Monkenbusch, M.; Richter, D.

    2007-01-01

    Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

  17. Mesonic and Quark Degrees of Freedom in the Neutron Star Matter

    International Nuclear Information System (INIS)

    Kubis, S.; Kutschera, M.; Niemiec, J.; Stachniewicz, S.

    1999-01-01

    Full text: It is expected that mesonic and quark degrees of freedom may play an important role in the physics of dense matter in neutron stars. Any conclusions, however, as to the presence of e.g. meson condensates and/or quark matter inside neutron stars are subject to uncertainties which reflect incompatible model predictions at a purely nucleon level. In our project, as far as mesonic contributions to the equation of state of dense matter are concerned, we focus on the role of kaons and the isovector scalar meson a 0 (980). We find that a threshold density for the kaon condensate to form is very sensitive to a high density behaviour of the electron chemical potential, which is not well known due to uncertainties of nucleon-nucleon interactions. An important effect of the inclusion of the a 0 meson is a splitting of proton and neutron masses in the neutron star matter. A proper construction of the nucleon-quark phase transition in dense neutron star matter predicts that nucleons and quarks coexist over a finite range of pressure, with quarks (nucleons) filling gradually larger (smaller) fraction of space. We find, using a simple bag-model equation of state for the quark matter, that properties of such a mixed quark-nucleon phase are determined by the behaviour of nucleon matter isobars which is sensitive to the nuclear symmetry energy at high densities. We study also implications of the presence of a mixed phase for the structure of neutron stars. (author)

  18. Solid neutron matter the energy density in the relativistic harmonic approximation

    International Nuclear Information System (INIS)

    Cattani, M.; Fernandes, N.C.

    A relativistic expression for the energy density as a function of particle density for solid neutron matter is obtained using Dirac's equation with a truncated harmonic potential. Ultrabaric and superluminous effects are not found in our approach [pt

  19. Symmetry Parameter Constraints from a Lower Bound on Neutron-matter Energy

    Energy Technology Data Exchange (ETDEWEB)

    Tews, Ingo [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195-1550 (United States); Lattimer, James M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Ohnishi, Akira [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Kolomeitsev, Evgeni E., E-mail: itews@uw.edu, E-mail: james.lattimer@stonybrook.edu, E-mail: ohnishi@yukawa.kyoto-u.ac.jp, E-mail: e.kolomeitsev@gsi.de [Faculty of Natural Sciences, Matej Bel University, Tajovskeho 40, SK-97401 Banska Bystrica (Slovakia)

    2017-10-20

    We propose the existence of a lower bound on the energy of pure neutron matter (PNM) on the basis of unitary-gas considerations. We discuss its justification from experimental studies of cold atoms as well as from theoretical studies of neutron matter. We demonstrate that this bound results in limits to the density-dependent symmetry energy, which is the difference between the energies of symmetric nuclear matter and PNM. In particular, this bound leads to a lower limit to the volume symmetry energy parameter S {sub 0}. In addition, for assumed values of S {sub 0} above this minimum, this bound implies both upper and lower limits to the symmetry energy slope parameter L , which describes the lowest-order density dependence of the symmetry energy. A lower bound on neutron-matter incompressibility is also obtained. These bounds are found to be consistent with both recent calculations of the energies of PNM and constraints from nuclear experiments. Our results are significant because several equations of state that are currently used in astrophysical simulations of supernovae and neutron star mergers, as well as in nuclear physics simulations of heavy-ion collisions, have symmetry energy parameters that violate these bounds. Furthermore, below the nuclear saturation density, the bound on neutron-matter energies leads to a lower limit to the density-dependent symmetry energy, which leads to upper limits to the nuclear surface symmetry parameter and the neutron-star crust–core boundary. We also obtain a lower limit to the neutron-skin thicknesses of neutron-rich nuclei. Above the nuclear saturation density, the bound on neutron-matter energies also leads to an upper limit to the symmetry energy, with implications for neutron-star cooling via the direct Urca process.

  20. Constraining the EOS of Neutron-Rich Nuclear Matter and Properties of Neutron Stars with Heavy-Ion Reactions

    International Nuclear Information System (INIS)

    Li Baoan; Worley, Aaron; Chen, L.-W.; Ko, Che Ming; Krastev, Plamen G.; Wen Dehua; Xiao Zhigang; Zhang Ming; Xu Jun; Yong Gaochan

    2009-01-01

    Heavy-ion reactions especially those induced by radioactive beams provide useful information about the density dependence of the nuclear symmetry energy, thus the Equation of State of neutron-rich nuclear matter, relevant for many astrophysical studies. The latest developments in constraining the symmetry energy at both sub- and supra-saturation densities from analyses of the isopsin diffusion and the π - /π + ratio in heavy-ion collisions using the IBUU04 transport model are discussed. Astrophysical ramifications of the partially constrained symmetry energy on properties of neutron star crusts, gravitational waves emitted by deformed pulsars and the w-mode oscillations of neutron stars are presented briefly.

  1. Properties of nuclear and neutron matter using D1 Gogny force

    International Nuclear Information System (INIS)

    Mansour, H.M.M.; Ramadan, Kh.A.; Hammad, M.

    2004-01-01

    In the present work, we investigate the equation of state of hot and cold nuclear and neutron matter using the Gogny effective interaction. The binding energy per particle, symmetry energies, free energy, and pressure are calculated as a function of the density ρ, fm -3 , for the nuclear and neutron matter. The results are comparable with previous theoretical estimates using the Seyler-Blanchard effective interaction and the famous calculation of Friedman and Pandharipande using a realistic interaction

  2. Softness of Nuclear Matter and the Production of Strange Particles in Neutron Stars

    Institute of Scientific and Technical Information of China (English)

    陈伟; 文德华; 刘良钢

    2003-01-01

    In the various models, we study the influences of the softness of nuclear matter, the vacuum fluctuation ofnucleons and σ mesons on the production of strange particles in neutron stars. Wefind that the stiffer the nuclear matter is, the more easily the strange particles is produced in neutron stars. The vacuum fluctuation of nucleons has large effect on strange particle production while that of σ meson has little effect on it.

  3. Interaction of neutrons with the matter in the laser field

    International Nuclear Information System (INIS)

    Zaretskij, D.F.; Lomonosov, V.V.

    1980-01-01

    The interactions of neutrons with the molecules, atoms and nuclei in the presence of the coherent electromagnetic radiation are considered. There are two effects which are discussed in detail: 1) the ''acceleration'' of thermal neutrons passed through the excited by the resonance laser wave molecular gas; 2) the induced by the laser field the slow neutron capture accompanied by the compound nucleus level excitation. The given effects, if they are experimentally detected, give the possibility to control the neutron flux (spectrum change, polarization, spatial modulation and etc.) and change the interaction cross sections of thermal and resonance neutrons with nuclei due to excitation of p levels of the compound nucleus [ru

  4. A pulsed neutron facility for condensed matter research

    International Nuclear Information System (INIS)

    Hobbis, L.C.W.; Rees, G.H.; Stirling, G.C.

    1977-06-01

    The scientific and technical basis of the project is presented, as follows: broad synopsis of the proposal for a spallation neutron facility; description of neutron scattering and current work in the UK; scientific applications of the Spallation Neutron Source; discussion of various types of neutron sources; outline description of the SNS and its neutron performance parameters; appendix dealing in more detail with utilization (solid state physics, fluids and amorphous solids, structure determination, molecular and biological sciences); appendix dealing in more detail with the project design (800 MeV synchrotron, target station, shielding, radioactivity and radiation damage, utilization, overall programme). (U.K.)

  5. Properties of Localized Protons in Neutron Star Matter at Finite Temperatures

    Science.gov (United States)

    Szmaglinski, A.; Kubis, S.; Wójcik, W.

    2014-02-01

    We study properties of the proton component of neutron star matter for realistic nuclear models. Vanishing of the nuclear symmetry energy implies proton-neutron separation in dense nuclear matter. Protons which form admixture tend to be localized in potential wells. Here, we extend the description of proton localization to finite temperatures. It appears that the protons are still localized at temperatures typical for hot neutron stars. That fact has important astrophysical consequences. Moreover, the temperature inclusion leads to unexpected results for the behavior of the proton localized state.

  6. Paul Scherrer Institute Scientific Report 1998. Volume III: Condensed Matter Research with Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, Juerg; Castellazzi, Denise; Bucher-Zimmermann, Claudia [eds.

    1999-09-01

    As a consequence of a major reorganisation at PSI, a new department has been formed with the groups focussing on research of condensed matter. The activities of the Laboratory of Neutron Scattering (jointly operated with the Swiss Federal Institute of Technology, ETH Zuerich), the Condensed Matter Theory Group, and the Group for Low Temperature Facilities, are described in this annual report figs., tabs., refs.

  7. Paul Scherrer Institute Scientific Report 1998. Volume III: Condensed Matter Research with Neutrons

    International Nuclear Information System (INIS)

    Schefer, Juerg; Castellazzi, Denise; Bucher-Zimmermann, Claudia

    1999-01-01

    As a consequence of a major reorganisation at PSI, a new department has been formed with the groups focussing on research of condensed matter. The activities of the Laboratory of Neutron Scattering (jointly operated with the Swiss Federal Institute of Technology, ETH Zuerich), the Condensed Matter Theory Group, and the Group for Low Temperature Facilities, are described in this annual report

  8. Instability of quark matter core in a compact newborn neutron star ...

    Indian Academy of Sciences (India)

    with moderately strong magnetic field strength, which populates only the electron's Landau levels, then in the β-equilibrium condition, the quark core is energetically much more unstable than the neutron matter of identical physical condition. Keywords. Landau diamagnetism; quark matter; quark star. PACS Nos 26.60.

  9. Neutron beams for the study of condensed matter: a view of the first half-century

    International Nuclear Information System (INIS)

    Bacon, G.E.

    1982-01-01

    Neutron diffraction was first demonstrated in 1936 but awaited the development of the nuclear reactor before becoming a practical technique for the study of condensed matter. Neutrons have unique advantages for the location of hydrogen atoms, the recognition of magnetic architecture and the study of crystal vibrations and atomic and molecular motions. The techniques available exploit the optical properties of neutrons over a wavelength range from 0.5 to 500 A. Progress has gone hand in hand with a steady increase of reactor flux over 50 years but future improvements may depend on pulsed linear accelerators as the source of neutrons. (author)

  10. Neutrino propagation in neutron matter and the nuclear equation of state

    CERN Document Server

    Margueron, J; Nguyen Van Giai; Jiang, W

    2001-01-01

    We study the propagation of neutrinos inside dense matter under the conditions prevailing in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme type and Gogny type) are first discussed. It is found that for many interactions, spin and/or isospin instabilities occur at densities larger than the saturation density of nuclear matter. From this study we select two representative interactions, SLy230b and D1P. We calculate the response functions in pure neutron matter where nuclear correlations are described at the Hartree-Fock plus RPA level. These response functions allow us to evaluate neutrino mean free paths corresponding to neutral current processes.

  11. Neutrons: The kinder, gentler probe of condensed matter

    International Nuclear Information System (INIS)

    Axe, J.D.

    1989-01-01

    Neutrons play an increasingly important role in the characterization of advanced modern materials. They provide information that complements rather than competes with that provided by other scattering probes. Although neutrons require heroic efforts to produce, the techniques for using them are not particularly difficult, and with the advent of sufficient user friendly facilities, are becoming a routine tool in the arsenal of expanding numbers of materials scientists. 10 refs., 5 figs

  12. Thermal neutron scattering studies of condensed matter under high pressures

    International Nuclear Information System (INIS)

    Carlile, C.J.; Salter, D.C.

    1978-01-01

    Although temperature has been used as a thermodynamic variable for samples in thermal neutron scattering experiments since the inception of the neutron technique, it is only in the last decade that high pressures have been utilised for this purpose. In the paper the problems particular to this field of work are outlined and a review is made of the types of high-pressure cells used and the scientific results obtained from the experiments. 103 references. (author)

  13. Neutron scattering for studies of soft matter at SNS and HFIR

    International Nuclear Information System (INIS)

    Smith, Gregory S.

    2013-01-01

    In this talk, we will present an overview of the scientific program of the Structure and Dynamics of Soft Matter Group, in the Biology and Soft Matter Division of the Neutron Sciences Directorate. From the broader area of soft materials research, the group members have chosen four main areas of scientific focus including: Confinement and Low-Dimensional Systems, Structure and Dynamics of Colloids, Nanoparticle-Polymer Composites, Transport in Membranes, and New Neutron Techniques for soft matter science. We will present several examples of neutron scattering experimental studies in each of these areas highlighting the experimental and theoretical (or modeling) capabilities of the group at both HFIR and SNS. Example topics to be discussed include SANS, reflectometry, and/or quasielastic studies of membranes on patterned interfaces, dynamics and structure of soft colloidal materials (including both polymeric dendrimers and biomimetic materials), gas confinement in mesoporous structures, transport in polyelectrolyte thin films, and development of spin-echo SANS concepts. (author)

  14. On the thermal properties of neutron matter with spin up excess

    International Nuclear Information System (INIS)

    Ramadan, S.; Montasser, S.S; Hassan, M.Y.M.

    1988-01-01

    The schematic model of pure hard core neutron matter proposed by Dabrowski et al. is generalized to finite temperature, where the attractive part of nuclear forces is treated as a perturbation. We calculate the potential energy, the energy per neutron, the volume and symmetry pressure, the magnetic susceptibility, the effective mass and the velocity of sound as a function of temperature. Our results are compared with previous calculations. 31 refs., 3 figs. (author)

  15. Exact solution of equations for proton localization in neutron star matter

    Science.gov (United States)

    Kubis, Sebastian; Wójcik, Włodzimierz

    2015-11-01

    The rigorous treatment of proton localization phenomenon in asymmetric nuclear matter is presented. The solution of proton wave function and neutron background distribution is found by the use of the extended Thomas-Fermi approach. The minimum of energy is obtained in the Wigner-Seitz approximation of a spherically symmetric cell. The analysis of four different nuclear models suggests that the proton localization is likely to take place in the interior of a neutron star.

  16. On the thermal properties of neutron matter with spin up excess

    International Nuclear Information System (INIS)

    Ramadan, S.; Montasser, S.S.; Hassan, M.Y.M.

    1986-07-01

    The schematic model of pure hard core neutron matter proposed by Dabrowski et al. is generalized to finite temperature, where the attractive part of nuclear forces is treated as a perturbation. We calculate the potential energy, the energy per neutron, the volume and symmetry pressure, the magnetic susceptibility, the effective mass and the velocity of sound as a function of temperature. Our results are compared with previous calculations. (author)

  17. Use of cold neutrons for condensed matter research at the neutron guide laboratory ELLA in Juelich

    International Nuclear Information System (INIS)

    Schaetzler, R.; Monkenbusch, M.

    1998-01-01

    Cold neutrons produced in the FRJ-2 DIDO reactor are guided into the external hall ELLA. It hosts 10 instruments that are red by three major neutron guides. Cold neutrons allow for diffraction and small angle scattering experiments resolving mesoscopic structures (1 to 100 nm). Contrast variation by isotopic substitution in chemically identical species yields information uniquely accessible bi neutrons. Inelastic scattering of cold neutrons allows investigating slow molecular motions because the low neutron velocity results in large relative velocity changes even at small energy transfers. The SANS machines and the HADAS reflectometer serve as structure probes and the backscattering BSS1 and spin-echo spectrometers NSE as main dynamics probes. Besides this the diffuse scattering instrument DNS and the lattice parameter determination instrument LAP deal mainly with crystals and their defects. Finally the beta-NMR and the EKN position allow for methods other than scattering employing nuclear reactions for solid state physics, chemistry and biology/medicine. (author)

  18. Neutron star evolution and the structure of matter at high density

    International Nuclear Information System (INIS)

    Soyeur, Madeleine.

    1981-09-01

    The structure and properties of neutron stars are determined by the state of cold nuclear matter at high density. In order to investigate the behavior of matter inside neutron stars, observables sensitive to their internal structure have to be calculated and confronted to observations. The thermal radiation of neutron stars seems to be a good candidate to be such observable. It can be shown that the neutrino luminosity of neutron stars, responsible for their cooling in the early stages of their evolution is strongly dependent on possible phase transitions to superfluid nucleons, to pion condensation or to quark matter. The specific heat of matter is also not the same in the various phases expected at high density and is particularly sensitive to the nucleon superfluidity. At present, both the theoretical estimates and the observations of the thermal properties of neutron stars are still quite preliminary. In particular, large uncertainties due to possible reheating mechanisms and magnetic field effects make the theoretical interpretation of the steady radiation of pulsars quite difficult

  19. A new nonlinear mean-field model of neutron star matter

    CERN Document Server

    Miyazaki, K

    2005-01-01

    A new relativistic mean-field model of neutron star matter is developed. It is a generalization of the Zimanyi-Moszkowski (ZM) model based on the constituent quark picture of baryons. The renormalized meson-hyperon coupling constants in medium are uniquely determined in contrast to the naive extention of ZM model and so the application of the model to high-density neutron star (NS) matter is possible. Our results of the particle composition and the mass-radius relation of NSs agree well with those obtained from the phenomenologically-determined realistic equation-of-state.

  20. Study of Neutrino-Induced Neutrons in Dark Matter Detectors for Supernova Burst Neutrinos

    Science.gov (United States)

    Kwan, Newton; Scholberg, Kate

    2017-09-01

    When supernova burst neutrinos (1-50 MeV) pass through the Earth, they occasionally interact with the passive shielding surrounding dark matter detectors. When the neutrinos interact, one or two roughly 2 MeV neutrons are scattered isotropically and uniformly, often leaving undetected. Occasionally, these neutrino-induced neutrons (NINs) interact with the detector and leave a background signal similar to a WIMP. The purpose of this study is to understand the effects of NINs on active dark matter detectors during a supernova burst.

  1. Neutron matter at next-to-next-to-next-to-leading order in chiral effective field theory.

    Science.gov (United States)

    Tews, I; Krüger, T; Hebeler, K; Schwenk, A

    2013-01-18

    Neutron matter presents a unique system for chiral effective field theory because all many-body forces among neutrons are predicted to next-to-next-to-next-to-leading order (N(3)LO). We present the first complete N(3)LO calculation of the neutron matter energy. This includes the subleading three-nucleon forces for the first time and all leading four-nucleon forces. We find relatively large contributions from N(3)LO three-nucleon forces. Our results provide constraints for neutron-rich matter in astrophysics with controlled theoretical uncertainties.

  2. Equation of state of dense nuclear matter and neutron star structure from nuclear chiral interactions

    Science.gov (United States)

    Bombaci, Ignazio; Logoteta, Domenico

    2018-02-01

    Aims: We report a new microscopic equation of state (EOS) of dense symmetric nuclear matter, pure neutron matter, and asymmetric and β-stable nuclear matter at zero temperature using recent realistic two-body and three-body nuclear interactions derived in the framework of chiral perturbation theory (ChPT) and including the Δ(1232) isobar intermediate state. This EOS is provided in tabular form and in parametrized form ready for use in numerical general relativity simulations of binary neutron star merging. Here we use our new EOS for β-stable nuclear matter to compute various structural properties of non-rotating neutron stars. Methods: The EOS is derived using the Brueckner-Bethe-Goldstone quantum many-body theory in the Brueckner-Hartree-Fock approximation. Neutron star properties are next computed solving numerically the Tolman-Oppenheimer-Volkov structure equations. Results: Our EOS models are able to reproduce the empirical saturation point of symmetric nuclear matter, the symmetry energy Esym, and its slope parameter L at the empirical saturation density n0. In addition, our EOS models are compatible with experimental data from collisions between heavy nuclei at energies ranging from a few tens of MeV up to several hundreds of MeV per nucleon. These experiments provide a selective test for constraining the nuclear EOS up to 4n0. Our EOS models are consistent with present measured neutron star masses and particularly with the mass M = 2.01 ± 0.04 M⊙ of the neutron stars in PSR J0348+0432.

  3. Computational methods for the nuclear and neutron matter problems. Progress report

    International Nuclear Information System (INIS)

    Kalos, M.H.

    1979-01-01

    A brief report is given of progress on the development of Monte Carlo methods for the treatment of both simplified and realistic models of extensive neutron and nuclear matter and, eventually, of finite nuclei. A wide class of algorithms that may allow the efficient sampling of the integrands required in calculating the energy expectations with useful trial wave functions was devised

  4. Characterization of airborne particulate matter in Santiago, Chile. Part 6: elemental determination by neutron activation analysis

    International Nuclear Information System (INIS)

    Cassorla, V.; Rojas, X.; Andonie, O.; Gras, N.

    1995-01-01

    Instrumental neutron activation analysis was used for the chemical characterization of airborne particulate matter from some locations in the city of Santiago, Chile. The following elements were determined: Al, As, Br, Ca, Cl, Co, Cu, Cr, Fe, Mn, Na, Sb, Sc, V y Zn. The accuracy of the experimental procedure was evaluated using a standard reference material. (author). 3 refs, 3 figs, 4 tabs

  5. Equation of state for neutron matter in the Quark Compound Bag model

    Science.gov (United States)

    Krivoruchenko, M. I.

    2017-11-01

    The equation of state for neutron matter is derived in the framework of the Quark Compound Bag model, in which the nucleon-nucleon interaction is generated by the s-channel exchange of six-quark Jaffe-Low primitives.

  6. Zero Sound in Neutron Stars with Dense Quark Matter under Strong Magnetic Fields

    DEFF Research Database (Denmark)

    Kouvaris, Christoforos

    2009-01-01

    We study a neutron star with a quark matter core under extremely strong magnetic fields. We investigate the possibility of an Urca process as a mechanism for the cooling of such a star. We found that apart from very particular cases, the Urca process cannot occur. We also study the stability...

  7. X-ray luminosity by matter accretion on a neutron star

    Energy Technology Data Exchange (ETDEWEB)

    Baroni, L [Bologna Univ. (Italy). Ist. di Fisica; Fortini, P L [Instituto di Astronomia, Bologna (Italy); Gualdi, C; Callegari, G [Ferrara Univ. (Italy). Ist. di Fisica

    1980-11-20

    When the accretion rate on a non magnetic neutron star is determined by stellar wind and not by overflowing the Roche lobe, it is shown that X-ray luminosity cannot exceed 10sup(36)-10sup(37) erg/sec. This very low limit is essentially set by radiation pressure which causes an effective braking on the falling matter.

  8. Rapid Cooling of the Neutron Star in Cassiopeia A Triggered by Neutron Superfluidity in Dense Matter

    International Nuclear Information System (INIS)

    Page, Dany; Prakash, Madappa; Lattimer, James M.; Steiner, Andrew W.

    2011-01-01

    We propose that the observed cooling of the neutron star in Cassiopeia A is due to enhanced neutrino emission from the recent onset of the breaking and formation of neutron Cooper pairs in the 3 P 2 channel. We find that the critical temperature for this superfluid transition is ≅0.5x10 9 K. The observed rapidity of the cooling implies that protons were already in a superconducting state with a larger critical temperature. This is the first direct evidence that superfluidity and superconductivity occur at supranuclear densities within neutron stars. Our prediction that this cooling will continue for several decades at the present rate can be tested by continuous monitoring of this neutron star.

  9. Use of ORELA to produce neutrons for scattering studies on condensed matter

    International Nuclear Information System (INIS)

    Peelle, R.W.; Lewis, T.A.; Mihalczo, J.T.; Mook, H.A.; Moon, R.M.

    1975-09-01

    The Oak Ridge Electron Linear Accelerator (ORELA) is evaluated as a source of neutrons for condensed matter research. Two options are assessed: (1) use of the present target arrangement with minor modifications; and (2) the construction of a new target and experiment facility designed for condensed matter research and equipped with a subcritical fission booster. The expected source strength and time behavior are discussed, including the fundamentals of moderator design. The effect on the programs presently using the linac are considered. It is concluded that a special-purpose neutron source facility using pulsed electrons from ORELA and containing a subcritical booster could be built to make a cost-effective neutron scattering facility of great power and utility. (auth)

  10. Signatures of field induced spin polarization of neutron star matter in seismic vibrations of paramagnetic neutron star

    International Nuclear Information System (INIS)

    Bastrukov, S I; Yang, J; Podgainy, D V; Weber, F

    2003-01-01

    A macroscopic model of the dissipative magneto-elastic dynamics of viscous spin polarized nuclear matter is discussed in the context of seismic activity of a paramagnetic neutron star. The source of the magnetic field of such a star is attributed to Pauli paramagnetism of baryon matter promoted by a seed magnetic field frozen into the star in the process of gravitational collapse of a massive progenitor. Particular attention is given to the effect of shear viscosity of incompressible stellar material on the timing of non-radial torsional magneto-elastic pulsations of the star triggered by starquakes. By accentuating the fact that this kind of vibration is unique to the seismology of a paramagnetic neutron star we show that the high-frequency modes decay faster than the low-frequency modes. The obtained analytic expressions for the period and relaxation time of this mode, in which the magnetic susceptibility and viscosity enter as input parameters, are then quantified by numerical estimates for these parameters taken from early and current works on transport coefficients of dense matter. It is found that the effect of viscosity is crucial for the lifetime of magneto-torsion vibrations but it does not appreciably affect the periods of this seismic mode which fall in the realm of periods of pulsed emission of soft gamma-ray repeaters and anomalous x-ray pulsars - young super-magnetized neutron stars, radiating, according to the magnetar model, at the expense of the magnetic energy release. Finally, we present arguments that the long periodic pulsed emission of these stars in a quiescent regime of radiation can be interpreted as a manifestation of weakly damped seismic magneto-torsion vibrations exhibiting the field induced spin polarization of baryon matter

  11. International Conference on Polarised Neutrons for Condensed Matter Investigations (PNCMI 2016)

    International Nuclear Information System (INIS)

    2017-01-01

    The present volume of the Journal of Physics: Conference Series represents Proceedings of the 11th International Conference on Polarised Neutrons for Condensed Matter Investigation (PNCMI) held in Freising, Germany from July 4–7, 2016. The conference attended by more than 120 scientists from various academic, government, and industrial institutions in Europe, Asia and the Americas was organized by the Jülich Centre for Neutron Science of the Forschungszentrum Jülich. The PNCMI-2016 continuoued the successful previous conferences in this series covering the latest condensed matter investigations using polarised neutrons and state-of-the-art methodologies, from effective polarization of neutron beams to wide-angle polarization analysis, as well as applications for novel instrumentation and experiments, with emphasis on prospects for new science and new instrument concepts. The conference program included invited and contributed oral presentations and posters which demonstrated the activities using polarized neutrons all over the world and showed the deep interest in developing the topic. The presentations tackled all area of science including multiferroic and chirality, strongly correlated electron systems, superconductors, frustrated and disordered systems, magnetic nanomaterials, thin films and multilayers, soft matter and biology, imaging, as well as further developments in polarized neutron techniques and methods, including nuclear polarisation, Larmor techniques and depolarisation methods.. We would like to thank all speakers for their presentations and all attendees for their participation. We would also like to gratefully acknowledge the financial support by J-PARC and AIRBUS DS as Premium Sponsors and Swiss Neutronics, ISIS, LLB, PSI and Mirrotron as Standard Sponsors of this conference. The next PNCMI will take place in Great Britain in 2018 and will be organized by ISIS. Alexander Ioffe (Conference Chair) Thomas Gutberlet (Conference Secretary) (paper)

  12. Nanotubes based neutron generator for calibration of neutrino and dark matter detectors

    Science.gov (United States)

    Chepurnov, A. S.; Ionidi, V. Y.; Kirsanov, M. A.; Kitsyuk, E. P.; Klenin, A. A.; Kubankin, A. S.; Oleinik, A. N.; Pavlov, A. A.; Shchagin, A. V.

    2017-12-01

    The compact 2.45 MeV fast neutron generator with a reduced supply voltage for calibration of low-background neutrino and dark matter detectors was tested. The generator is based on an array of carbon nanotubes. Neutron generation is carried out by applying a high voltage in the range of +10 to + 25 kV to a nanotube array, which cause an ionization of deuterium molecules with the following acceleration of ions in the direction of the grounded target covered by a deuterated polyethylene film. The d(d,n)3He nuclear reaction happens as the result of ions collisions with the target. The dependences of the neutron yield as functions of the applied voltage were obtained for two different types of carbon nanotubes array. It is shown that the type of nanotubes array does not influence significantly on the neutron yield.

  13. New relativistic effective interaction for finite nuclei, infinite nuclear matter, and neutron stars

    Science.gov (United States)

    Kumar, Bharat; Patra, S. K.; Agrawal, B. K.

    2018-04-01

    We carry out the study of finite nuclei, infinite nuclear matter, and neutron star properties with the newly developed relativistic force, the Institute of Physics Bhubaneswar-I (IOPB-I). Using this force, we calculate the binding energies, charge radii, and neutron-skin thickness for some selected nuclei. From the ground-state properties of superheavy nuclei (Z =120 ), it is noticed that considerable shell gaps appear at neutron numbers N =172 , 184, and 198, manifesting the magicity at these numbers. The low-density behavior of the equation of state for pure neutron matter is compatible with other microscopic models. Along with the nuclear symmetry energy, its slope and curvature parameters at the saturation density are consistent with those extracted from various experimental data. We calculate the neutron star properties with the equation of state composed of nucleons and leptons in β -equilibrium, which are in good agreement with the x-ray observations by Steiner [Astrophys. J. 722, 33 (2010), 10.1088/0004-637X/722/1/33] and Nättilä [Astron. Astrophys. 591, A25 (2016), 10.1051/0004-6361/201527416]. Based on the recent observation of GW170817 with a quasi-universal relation, Rezzolla et al. [Astrophys. J. Lett. 852, L25 (2018), 10.3847/2041-8213/aaa401] have set a limit for the maximum mass that can be supported against gravity by a nonrotating neutron star in the range 2.01 ±0.04 ≲M (M⊙)≲2.16 ±0.03 . We find that the maximum mass of the neutron star for the IOPB-I parametrization is 2.15 M⊙ . The radius and tidal deformability of a canonical neutron star of mass 1.4 M⊙ are 13.2 km and 3.9 ×1036g cm2s2 , respectively.

  14. Diffusive instability of a kaon condensate in neutron star matter

    International Nuclear Information System (INIS)

    Kubis, Sebastian

    2004-01-01

    The beta equilibrated dense matter with kaon condensate is analyzed with respect to extended stability conditions, including charge fluctuations. This kind of the diffusive instability appeared to be common property in the kaon condensation case. Results for three different nuclear models are presented

  15. The Equation of State of Neutron Star Matter in Strong Magnetic Fields

    International Nuclear Information System (INIS)

    Broderick, A.; Prakash, M.; Lattimer, J. M.

    2000-01-01

    We study the effects of very strong magnetic fields on the equation of state (EOS) in multicomponent, interacting matter by developing a covariant description for the inclusion of the anomalous magnetic moments of nucleons. For the description of neutron star matter, we employ a field-theoretical approach, which permits the study of several models that differ in their behavior at high density. Effects of Landau quantization in ultrastrong magnetic fields (B>10 14 G) lead to a reduction in the electron chemical potential and a substantial increase in the proton fraction. We find the generic result for B>10 18 G that the softening of the EOS caused by Landau quantization is overwhelmed by stiffening due to the incorporation of the anomalous magnetic moments of the nucleons. In addition, the neutrons become completely spin polarized. The inclusion of ultrastrong magnetic fields leads to a dramatic increase in the proton fraction, with consequences for the direct Urca process and neutron star cooling. The magnetization of the matter never appears to become very large, as the value of |H/B| never deviates from unity by more than a few percent. Our findings have implications for the structure of neutron stars in the presence of large frozen-in magnetic fields. (c) 2000 The American Astronomical Society

  16. The Equation of State of Neutron Star Matter in Strong Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, A; Prakash, M; Lattimer, J M

    2000-07-01

    We study the effects of very strong magnetic fields on the equation of state (EOS) in multicomponent, interacting matter by developing a covariant description for the inclusion of the anomalous magnetic moments of nucleons. For the description of neutron star matter, we employ a field-theoretical approach, which permits the study of several models that differ in their behavior at high density. Effects of Landau quantization in ultrastrong magnetic fields (B>10{sup 14} G) lead to a reduction in the electron chemical potential and a substantial increase in the proton fraction. We find the generic result for B>10{sup 18} G that the softening of the EOS caused by Landau quantization is overwhelmed by stiffening due to the incorporation of the anomalous magnetic moments of the nucleons. In addition, the neutrons become completely spin polarized. The inclusion of ultrastrong magnetic fields leads to a dramatic increase in the proton fraction, with consequences for the direct Urca process and neutron star cooling. The magnetization of the matter never appears to become very large, as the value of |H/B| never deviates from unity by more than a few percent. Our findings have implications for the structure of neutron stars in the presence of large frozen-in magnetic fields. (c) 2000 The American Astronomical Society.

  17. Paul Scherrer Institute Scientific Report 2000. Volume III: Condensed Matter Research with Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, Juerg; Castellazzi, Denise; Shea-Braun, Margit [eds.

    2001-07-01

    This year started with a highlight for the Swiss Spallation Neutron Source SINQ located at PSI: The thermal neutron flux exceeded the value of 10{sup 14} n cm{sup -2} s{sup 1} which may be considered as the critical limit for an advanced medium-flux neutron source. The excellent performance attracted a large number of external users to participate at the neutron scattering programme. The major part of this annual report gives an overview on the scientific activities of the staff members of the Laboratory of Neutron Scattering (jointly operated with the Swiss Federal Institute of Technology, ETH Zurich). The research topics covered diverse areas such as strongly correlated electron systems including high-temperature superconductors, low-dimensional and quantum magnetism, materials research on soft and hard matter including multilayers. Progress in 2000 in these topical areas as well as the activities of the Condensed Matter Theory Group, and the Group for Low Temperature Facilities, is described in this report. A list of scientific publications in 2000 is also provided.

  18. Paul Scherrer Institute Scientific Report 2000. Volume III: Condensed Matter Research with Neutrons

    International Nuclear Information System (INIS)

    Schefer, Juerg; Castellazzi, Denise; Shea-Braun, Margit

    2001-01-01

    This year started with a highlight for the Swiss Spallation Neutron Source SINQ located at PSI: The thermal neutron flux exceeded the value of 10 14 n cm -2 s 1 which may be considered as the critical limit for an advanced medium-flux neutron source. The excellent performance attracted a large number of external users to participate at the neutron scattering programme. The major part of this annual report gives an overview on the scientific activities of the staff members of the Laboratory of Neutron Scattering (jointly operated with the Swiss Federal Institute of Technology, ETH Zurich). The research topics covered diverse areas such as strongly correlated electron systems including high-temperature superconductors, low-dimensional and quantum magnetism, materials research on soft and hard matter including multilayers. Progress in 2000 in these topical areas as well as the activities of the Condensed Matter Theory Group, and the Group for Low Temperature Facilities, is described in this report. A list of scientific publications in 2000 is also provided

  19. Neutron research on condensed matter: a study of the facilities and scientific opportunities in the United States

    International Nuclear Information System (INIS)

    1977-01-01

    An in-depth review of the present status and future potential of the applications of low-energy neutron scattering to research in the condensed-matter sciences, including physics, chemistry, biology, and metallurgy is presented. The study shows that neutron scattering technology has proven to be of enormous importance to research in the above areas and especially to those of solid-state physics and chemistry. The main emphasis is on the scattering of low-energy neutrons by condensed matter. Since the same type of neutron source facilities can be used for the study of radiation damage, this related topic has also been included

  20. Workbook on reactor neutron activation analysis (NAA) of airborne particulate matter (APM)

    International Nuclear Information System (INIS)

    Tian Weizhi

    2000-01-01

    This publication presents general aspects of reactor neutron activation analysis (NAA) applied to measurement of elemental composition of airborne particulate matter. It presents an introduction to the NAA, its' basic principles and brief history of the method and discusses its' advantages and disadvantages. This publication also presents experimental procedures of NAA including sampling and sample preparation; preparation of calibration standard samples; reactor neutron irradiation; gamma-spectroscopy of the irradiated samples; quantification and presentation of analytical results. The publication pays attention to the quality assurance and quality control procedures including internal quality control, analysis of certified reference materials, and interlaboratory and multi-method comparison studies, control charts

  1. Spin ordered phase transitions in neutron matter under the presence of a strong magnetic field

    International Nuclear Information System (INIS)

    Isayev, A.A.; Yang, J.

    2011-01-01

    In dense neutron matter under the presence of a strong magnetic field, considered in the model with the Skyrme effective interaction, there are possible two types of spin ordered states. In one of them the majority of neutron spins are aligned opposite to magnetic field (thermodynamically preferable state), and in other one the majority of spins are aligned along the field (metastable state). The equation of state, incompressibility modulus and velocity of sound are determined in each case with the aim to find the peculiarities allowing to distinguish between two spin ordered phases.

  2. Magnetization of neutron star matter and implications in physics of soft gamma repeaters

    Energy Technology Data Exchange (ETDEWEB)

    Kondratyev, V N [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-01-01

    The magnetization of neutron star matter is considered within the thermodynamic formalism. The quantization effects are demonstrated to result in sharp abrupt magnetic field dependence of nuclide magnetic moments. Accounting for inter-nuclide magnetic coupling we show that such anomalies give rise to erratic jumps in magnetotransport of neutron star crusts. The properties of such a noise are favorably compared with burst statistics of Soft Gamma Repeaters. PACS: 97.60.Jd, 21.10.Dr, 26.60.+c, 95.30.Ky. (author)

  3. Plan for the future of neutron research on condensed matter: an Argonne National Laboratory report prepared in response to the Report of the Review Panel on Neutron Scattering

    International Nuclear Information System (INIS)

    1981-01-01

    The Review Panel on Neutron Scattering has recommended an expanded budget to allow systematic development of the field. An alternative plan for the future of neutron research on condensed matter is presented here, in case it is not possible to fund the expanded budget. This plan leads, in a rational and logical way, to a world-class neutron source that will ensure the vitality of the field and exploit the many benefits that state-of-the-art neutron facilities can bring to programs in the materials and biological sciences. 2 tables

  4. Bookshelf (''Neutrons, Nuclei and Matter'', by J. Byrne)

    International Nuclear Information System (INIS)

    Hansen, P.G.

    1994-01-01

    Time was when a neophyte wanting to do experiments with neutrons would be told first to read D.J. Hughes' classic ''Pile Neutron Research'' (1952). The book by J. Byrne is in many respects a modern equivalent, although if you were to send your student away with it, you will risk not seeing him or her again for a considerable time. What is immediately striking is that the book, rich in information and quite long, is cross-disciplinary and touches essentially all the main areas of modern physics. It covers parts of particle physics, such as the internal structure of the neutron, time-reversal violation as revealed by the (still hypothetical) electric dipole moment of the neutron, and the coupling constants for the weak interaction. From the field of basic quantum physics there are chapters on neutron optics, wave phenomena with neutrons and on the applications of these in solid-state physics. Other chapters again delve deeply into nuclear structure, nuclear reaction theory, as well as their applications: nuclear reactors and nuclear energy. At a time with specialization rampant and many physicists tending to believe that venturing outside their own cloisters is uninteresting and even dangerous, it is a pleasure to come across a book that is basically just about physics. J. Byrne of Sussex has for long been active in neutron research at the British-French-German Institut Laue-Langevin (ILL) research reactor in Grenoble, where he has worked on subjects such as weak interactions and fundamental symmetries. He has clearly intended ''Neutrons, Nuclei and Matter'' as a vade-mecum that will allow the practitioner to find the necessary information and formulas. But I believe that many others not directly engaged in neutron research will gain new insight from its many examples. To take just one case, I had not been aware of the simple physical principles that permit cold neutrons to be stored in a bottle. (The main point is that a

  5. arXiv Gravitational-wave constraints on the neutron-star-matter Equation of State

    CERN Document Server

    Annala, Eemeli; Kurkela, Aleksi; Vuorinen, Aleksi

    The LIGO/Virgo detection of gravitational waves originating from a neutron-star merger, GW170817, has recently provided new stringent limits on the tidal deformabilities of the stars involved in the collision. Combining this measurement with the existence of two-solar-mass stars, we generate a generic family of neutron-star-matter Equations of State (EoSs) that interpolate between state-of-the-art theoretical results at low and high baryon density. Comparing the results to ones obtained without the tidal-deformability constraint, we witness a dramatic reduction in the family of allowed EoSs. Based on our analysis, we conclude that the maximal radius of a 1.4-solar-mass neutron star is 13.6 km, and that smallest allowed tidal deformability of a similar-mass star is $\\Lambda(1.4 M_\\odot) = 120$.

  6. Gravitational-Wave Constraints on the Neutron-Star-Matter Equation of State

    Science.gov (United States)

    Annala, Eemeli; Gorda, Tyler; Kurkela, Aleksi; Vuorinen, Aleksi

    2018-04-01

    The detection of gravitational waves originating from a neutron-star merger, GW170817, by the LIGO and Virgo Collaborations has recently provided new stringent limits on the tidal deformabilities of the stars involved in the collision. Combining this measurement with the existence of two-solar-mass stars, we generate a generic family of neutron-star-matter equations of state (EOSs) that interpolate between state-of-the-art theoretical results at low and high baryon density. Comparing the results to ones obtained without the tidal-deformability constraint, we witness a dramatic reduction in the family of allowed EOSs. Based on our analysis, we conclude that the maximal radius of a 1.4-solar-mass neutron star is 13.6 km, and that the smallest allowed tidal deformability of a similar-mass star is Λ (1.4 M⊙)=120 .

  7. arXiv Gravitational-wave constraints on the neutron-star-matter Equation of State

    CERN Document Server

    Annala, Eemeli; Kurkela, Aleksi; Vuorinen, Aleksi

    2018-04-26

    The detection of gravitational waves originating from a neutron-star merger, GW170817, by the LIGO and Virgo Collaborations has recently provided new stringent limits on the tidal deformabilities of the stars involved in the collision. Combining this measurement with the existence of two-solar-mass stars, we generate a generic family of neutron-star-matter equations of state (EOSs) that interpolate between state-of-the-art theoretical results at low and high baryon density. Comparing the results to ones obtained without the tidal-deformability constraint, we witness a dramatic reduction in the family of allowed EOSs. Based on our analysis, we conclude that the maximal radius of a 1.4-solar-mass neutron star is 13.6 km, and that the smallest allowed tidal deformability of a similar-mass star is Λ(1.4  M⊙)=120.

  8. Neutron and synchrotron radiation for condensed matter studies. Volume 1: theory, instruments and methods

    International Nuclear Information System (INIS)

    Baruchel, J.; Hodeau, J.L.; Lehmann, M.S.; Regnard, J.R.; Schlenker, C.

    1993-01-01

    This book provides the basic information required by a research scientist wishing to undertake studies using neutrons or synchrotron radiation at a Large Facility. These lecture notes result from 'HERCULES', a course that has been held in Grenoble since 1991 to train young scientists in these fields. They cover the production of neutrons and synchrotron radiation and describe all aspects of instrumentation. In addition, this work outlines the basics of the various fields of research pursued at these Large Facilities. It consists of a series of chapters written by experts in the particular fields. While following a progression and constituting a lecture course on neutron and x-ray scattering, these chapters can also be read independently. This first volume will be followed by two further volumes concerned with the applications to solid state physics and chemistry, and to biology and soft condensed matter properties

  9. Neutron star properties and the relativistic nuclear equation of state of many-baryon matter

    International Nuclear Information System (INIS)

    Weber, F.; Weigel, M.K.

    1989-01-01

    A relativistic model of baryons interacting via the exchange of σ-, ω-, π- and ρ-mesons (scalar-vector-isovector (SVI) theory) is used to describe the properties of both dense and superdense matter. For the theoretical frame, we used the temperature-dependent Green's function formalism. The equation of state (EOS) is calculated for nuclear as well as neutron matter in the Hartree (H) and Hartree-Fock (HF) approximation. The existence of phase transitions has been investigated. The isotherms of pressure as a function of density show for nuclear matter a critical temperature of about T c HF =16.6 MeV. (As in the usual scalar-vector (SV) theory, the phase transition is absent for neutron matter. A phase transition of both many-baryon systems in the high-pressure and high-density region, which has been found within the SV many-baryon theory, appears in the SVI theory too. The calculated maximum stable masses of neutron stars depend on 1. the underlying parameter set and/or 2. on the chosen approximation (i.e., H, HF; SV-, SVI theory, respectively). Hartree calculations lead to a mass stability limit of M max H ≤2.87 M sun (M max H ≤2.44 M sun when hyperons are taken into account). For the HF calculations we obtained M max HF ≤3.00 M sun (M max HF ≤2.85 M sun ). The corresponding maximum radii are (same notation as above) R H ≤13.2 km (R H ≤11.8 km), R HF ≤14.0 km (R HF ≤13.94 km).) The influence of the approximations, parameter sets and hyperons on the neutron star's moment of inertia is exhibited. (orig.)

  10. Relaxation of the chiral imbalance in dense matter of a neutron star

    Directory of Open Access Journals (Sweden)

    Dvornikov Maxim

    2016-01-01

    Full Text Available Using the quantum field theory methods, we calculate the helicity flip of an electron scattering off protons in dense matter of a neutron star. The influence of the electroweak interaction between electrons and background nucleons on the helicity flip is examined. We also derive the kinetic equation for the chiral imbalance. The derived kinetic equation is compared with the results obtained by other authors.

  11. Equation of state of neutron-rich nuclear matter from chiral effective field theory

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Norbert; Strohmeier, Susanne [Technische Universitaet Muenchen (Germany)

    2016-07-01

    Based on chiral effective field theory, the equation of state of neutron-rich nuclear matter is investigated systematically. The contributing diagrams include one- and two-pion exchange together with three-body terms arising from virtual Δ(1232)-isobar excitations. The proper expansion of the energy per particle, anti E(k{sub f},δ) = anti E{sub n}(k{sub f}) + δB{sub 1}(k{sub f}) + δ{sup 5/3}B{sub 5/3}(k{sub f}) + δ{sup 2}B{sub 2}(k{sub f}) +.., for the system with neutron density ρ{sub n} = k{sub f}{sup 3}(1-δ)/3π{sup 2} and proton density ρ{sub p} = k{sub f}{sup 3}δ/3π{sup 2} is performed analytically for the various interaction contributions. One observes essential structural differences to the commonly used quadratic approximation. The density dependent coefficient B{sub 1}(k{sub f}) turns out to be unrelated to the isospin-asymmetry of nuclear matter. The coefficient B{sub 5/3}(k{sub f}) of the non-analytical δ{sup 5/3}-term receives contributions from the proton kinetic energy and from the one- and two-pion exchange interactions. The physical consequences for neutron star matter are studied.

  12. General analysis for experimental studies of time-reversal-violating effects in slow neutron propagation through polarized matter

    International Nuclear Information System (INIS)

    Lamoreaux, S.K.; Golub, R.

    1994-01-01

    A general technique is developed for the analysis of proposed experimental studies of possible P,T-violating effects in the neutron-nucleus interaction based on low-energy neutron transmission through polarized matter. The analysis is applied to proposed experimental schemes and we determine the levels at which the absolute neutron polarization, magnetic fields, and target polarization must be controlled in order for these experiments to obtain a given sensitivity to P,T-violating effects

  13. Asymmetric nuclear matter and neutron star properties within the extended Brueckner theory

    Energy Technology Data Exchange (ETDEWEB)

    Hassaneen, Khaled S.A. [Sohag University, Physics Department, Faculty of Science, Sohag (Egypt); Taif University, Physics Department, Faculty of Science, Taif (Saudi Arabia)

    2017-01-15

    Microscopically, the equation of state (EOS) and other properties of asymmetric nuclear matter at zero temperature have been investigated extensively by adopting the non-relativistic Brueckner-Hartree-Fock (BHF) and the extended BHF approaches by using the self-consistent Green's function approach or by including a phenomenological three-body force. Once three-body forces are introduced, the phenomenological saturation point is reproduced and the theory is applied to the study of neutron star properties. We can calculate the total mass and radius for neutron stars using various equations of state at high densities in β-equilibrium without hyperons. A comparison with other microscopic predictions based on non-relativistic and density-dependent relativistic mean-field calculations has been done. It is found that relativistic EOS yields however larger mass and radius for neutron star than predictions based on non-relativistic approaches. Also the three-body force plays a crucial role to deduce the theoretical value of the maximum mass of neutron stars in agreement with recent measurements of the neutron star mass. (orig.)

  14. Finite temperature effects on anisotropic pressure and equation of state of dense neutron matter in an ultrastrong magnetic field

    International Nuclear Information System (INIS)

    Isayev, A. A.; Yang, J.

    2011-01-01

    Spin-polarized states in dense neutron matter with the recently developed Skyrme effective interaction (BSk20 parametrization) are considered in the magnetic fields H up to 10 20 G at finite temperature. In a strong magnetic field, the total pressure in neutron matter is anisotropic, and the difference between the pressures parallel and perpendicular to the field direction becomes significant at H>H th ∼10 18 G. The longitudinal pressure decreases with the magnetic field and vanishes in the critical field 10 18 c 19 G, resulting in the longitudinal instability of neutron matter. With increasing temperature, the threshold H th and critical H c magnetic fields also increase. The appearance of the longitudinal instability prevents the formation of a fully spin-polarized state in neutron matter and only the states with moderate spin polarization are accessible. The anisotropic equation of state is determined at densities and temperatures relevant to the interiors of magnetars. The entropy of strongly magnetized neutron matter turns out to be larger than the entropy of nonpolarized matter. This is caused by some specific details in the dependence of the entropy on the effective masses of neutrons with spin up and spin down in a polarized state.

  15. Equation of State of Dense Matter and Consequences for Neutron Stars

    Directory of Open Access Journals (Sweden)

    Thomas A. W.

    2013-12-01

    Full Text Available There is currently tremendous interest in the role of hyperons and other exotic forms of matter in neutron stars. This is particularly so following the measurement by Demorest et al. of a star with a mass almost 2 solar masses. Given that we know of no physical mechanism to stop the occurrence of hyperons at matter in beta–equilibrium above roughly 3 times nuclear matter density, we discuss the constraints on the possible maximum mass when hyperons are included in the equation of state. The discussion includes a careful assessment of the constraints from low energy nuclear properties as well as the properties of hypernuclei. The model within which these calculations are carried out is the quark-meson coupling (QMC model, which is derived starting at the quark level.

  16. Sensitivity of the moment of inertia of neutron stars to the equation of state of neutron-rich matter

    International Nuclear Information System (INIS)

    Fattoyev, F. J.; Piekarewicz, J.

    2010-01-01

    The sensitivity of the stellar moment of inertia to the neutron-star matter equation of state is examined using accurately calibrated relativistic mean-field models. We probe this sensitivity by tuning both the density dependence of the symmetry energy and the high-density component of the equation of state, properties that are at present poorly constrained by existing laboratory data. Particularly attractive is the study of the fraction of the moment of inertia contained in the solid crust. Analytic treatments of the crustal moment of inertia reveal a high sensitivity to the transition pressure at the core-crust interface. This may suggest the existence of a strong correlation between the density dependence of the symmetry energy and the crustal moment of inertia. However, no correlation was found. We conclude that constraining the density dependence of the symmetry energy - through, for example, the measurement of the neutron skin thickness in 208 Pb - will place no significant bound on either the transition pressure or the crustal moment of inertia.

  17. Spin-polarized states in neutron matter in a strong magnetic field

    International Nuclear Information System (INIS)

    Isayev, A. A.; Yang, J.

    2009-01-01

    Spin-polarized states in neutron matter in strong magnetic fields up to 10 18 G are considered in the model with the Skyrme effective interaction. By analyzing the self-consistent equations at zero temperature, it is shown that a thermodynamically stable branch of solutions for the spin-polarization parameter as a function of density corresponds to the negative spin polarization when the majority of neutron spins are oriented opposite to the direction of the magnetic field. Besides, beginning from some threshold density dependent on magnetic field strength, the self-consistent equations also have two other branches of solutions for the spin-polarization parameter with the positive spin polarization. The free energy corresponding to one of these branches turns out to be very close to that of the thermodynamically preferable branch. As a consequence, in a strong magnetic field, the state with the positive spin polarization can be realized as a metastable state in the high-density region in neutron matter, which, under decreasing density, at some threshold density changes to a thermodynamically stable state with the negative spin polarization.

  18. Neutron optical potentials in unstable nuclei and the equation of state of asymmetric nuclear matter

    International Nuclear Information System (INIS)

    Oyamatsu, K.; Iida, K.

    2003-01-01

    Neutron single particle potential is one of the basic macroscopic properties to describe structure and reactions of nuclei in nuclear reactors and in the universe. However, the potential is quite uncertain for unstable nuclei primarily because the equation of state (EOS) of asymmetric nuclear matter is not known well. The present authors studied systematically the empirical EOS of asymmetric nuclear matter using a macroscopic nuclear model; about two hundred EOS's having empirically allowed values of L (symmetry energy density derivative coefficient) and K 0 (incompressibility) were obtained from the fittings to masses and radii of stable nuclei. It was suggested that the L value could be determined from global (Z, A) dependence of nuclear radii. In the present study, the single particle potential is examined assuming kinetic energies of non-interacting Fermi gases. The potential in a nucleus can be calculated easily, once the density distribution is solved using the effective nuclear interaction (EOS). Neutron and proton single particle potentials are calculated systematically for 80 Ni using the two hundred EOS's. It is found that the neutron-proton potential difference has clear and appreciable L dependence, while the potential for each species does not show such simple dependence on L. (author)

  19. Effects of Brown-Rho scalings in nuclear matter, neutron stars and finite nuclei

    Science.gov (United States)

    Kuo, T. T. S.; Dong, Huan

    2011-01-01

    We have carried out calculations for nuclear matter, neutron stars and finite nuclei using NN potentials with and without the medium-dependent modifications based on the Brown-Rho (BR) scalings. Using the Vlow-k low-momentum interactions derived from such potentials, the equations of state (EOS) for symmetric and asymmetric nuclear matter, for densities up to ~ 5ρ0, are calculated using a RPA method where the particle-particle hole-hole ring diagrams are summed to all orders. The medium effects from both a linear BR scaling (BR1) and a non-linear one (BR2) are considered, and they both are essential for our EOSs to reproduce the nuclear matter saturation properties. For densities ρ below ρ0, results from BR1 and BR2 are close to each other. For higher densities, the EOS given by BR2 is more desirable and is well reproduced by that given by the interaction (Vlow-k+TBF) where Vlow-k is the unsealed low-momentum interaction and TBF is an empirical Skyrme three-body force. The moment of inertia of neutron stars is ~ 60 and ~ 25Modotkm2 respectively with and without the inclusion of the above BR2 medium effects. Effects from the BR scaling are important for the long half-life, ~ 5000yrs, of the 14C - 14N β-decay.

  20. Phenomenological neutron star equations of state. 3-window modeling of QCD matter

    Energy Technology Data Exchange (ETDEWEB)

    Kojo, Toru [University of Illinois at Urbana-Champaign, Department of Physics, Urbana, Illinois (United States)

    2016-03-15

    We discuss the 3-window modeling of cold, dense QCD matter equations of state at density relevant to neutron star properties. At low baryon density, n{sub B} neutron star radii. At high density, n{sub B} >or similar 5n{sub s}, we use the percolated quark matter equations of state which must be very stiff to pass the two-solar mass constraints. The intermediate domain at 2 matter, and the equations of state are inferred by interpolating hadronic and percolated quark matter equations of state. Possible forms of the interpolation are severely restricted by the condition on the (square of) speed of sound, 0 ≤ c{sub s}{sup 2} ≤ 1. The characteristics of the 3-window equation of state are compared with those of conventional hybrid and self-bound quark matters. Using a schematic quark model for the percolated domain, it is argued that the two-solar mass constraint requires the model parameters to be as large as their vacuum values, indicating that the gluon dynamics remains strongly non-perturbative to n{sub B} ∝ 10n{sub s}. The hyperon puzzle is also briefly discussed in light of quark descriptions. (orig.)

  1. 1S0 proton superfluidity in neutron star matter: Impact of bulk properties

    International Nuclear Information System (INIS)

    Tanigawa, Tomonori; Matsuzaki, Masayuki; Chiba, Satoshi

    2004-01-01

    We study the 1 S 0 proton pairing gap in neutron star matter putting emphasis on influence of the Dirac effective mass and the proton fraction on the gap within the relativistic Hartree-Bogoliubov model. The gap equation is solved using the Bonn-B potential as a particle-particle channel interaction. It is found that the maximal pairing gap Δ max is 1-2 MeV, which has a strong correlation with the Dirac effective mass. Hence we suggest that it serves as a guide to narrow down parameter sets of the relativistic effective field theory. Furthermore, the more slowly protons increase with density in the core region of neutron stars, the wider the superfluid range and the slightly lower the peak of the gap become

  2. Neutrino-'pasta' scattering: The opacity of nonuniform neutron-rich matter

    International Nuclear Information System (INIS)

    Horowitz, C.J.; Perez-Garcia, M.A.; Piekarewicz, J.

    2004-01-01

    Neutron-rich matter at subnuclear densities may involve complex structures displaying a variety of shapes, such as spherical, slablike, and/or rodlike shapes. These phases of the nuclear pasta are expected to exist in the crust of neutron stars and in core-collapse supernovae. The dynamics of core-collapse supernovae is very sensitive to the interactions between neutrinos and nucleons/nuclei. Indeed, neutrino excitation of the low-energy modes of the pasta may allow for a significant energy transfer to the nuclear medium, thereby reviving the stalled supernovae shock. The linear response of the nuclear pasta to neutrinos is modeled via a simple semiclassical simulation. The transport mean free path for μ and τ neutrinos (and antineutrinos) is expressed in terms of the static structure factor of the pasta, which is evaluated using Metropolis Monte Carlo simulations

  3. Unveiling the equation of state of nuclear matter with binary neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Galeazzi, F.; Rezzolla, L. [Frankfurt Univ., Frankfurt am Main (Germany). Inst. for Theoretical Physics

    2016-11-01

    2015 marked the hundred anniversary of Albert Einstein's lecture at the Prussian Academy of Science in which he introduced, for the first time, the famous field equations which became the core of his theory of general relativity. This masterpiece of 20th century science has proven extremely solid in all its predictions from the precession of the perihelion of Mercury to the observation of gravitational lensing in distant galaxies, to the more mundane time-delay corrections required by the global positioning system. One last piece of the puzzle is although still missing and comprise the direct measurement of the gravitational wave (GW) radiation emitted by any accelerating mass. These ripples in the spacetime fabric are extremely weak even when produced in the most extreme of the conditions as the ones present during the mergers of two black holes or neutron stars. For this reason they have eluded experimental scientists for almost four decades. But things are about to change, last year a new array of advanced gravitational wave detectors, namely advanced LIGO and Virgo came online in late September and they are expected to observe up to 40 events per year involving the mergers of two compact objects. Despite the high sensitivity of this generation of ground base interferometers, it is still necessary to use accurate gravitational waveforms models to extract all the information from the signal produced by the detector. In this project we focus on the merger of two neutron stars which orbit together in a binary system. The nonlinear nature of the Einstein equations coupled with the complex microphysics behind neutron star matter requires the use of sophisticated codes which uses advanced numerical techniques to produce accurate results. By using the GW signals calculated in our numerical simulations we will be able to strongly link the properties of neutron star matter to a precise set of observable frequencies from the detector. This information, together with

  4. Intrinsic neutron background of nuclear emulsions for directional Dark Matter searches

    Science.gov (United States)

    Alexandrov, A.; Asada, T.; Buonaura, A.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Di Vacri, M. L.; Furuya, S.; Galati, G.; Gentile, V.; Katsuragawa, T.; Laubenstein, M.; Lauria, A.; Loverre, P. F.; Machii, S.; Monacelli, P.; Montesi, M. C.; Naka, T.; Pupilli, F.; Rosa, G.; Sato, O.; Strolin, P.; Tioukov, V.; Umemoto, A.; Yoshimoto, M.

    2016-07-01

    Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP signal. In this paper we provide an estimation of the contribution to this background from the intrinsic radioactive contamination of nuclear emulsions. We also report the neutron-induced background as a function of the read-out threshold, by using a GEANT4 simulation of the nuclear emulsion, showing that it amounts to about 0.06 per year per kilogram, fully compatible with the design of a 10 kg × year exposure.

  5. PIXE and neutron activation analysis: intercomparison in the elemental concentration of airborne particulate matter

    International Nuclear Information System (INIS)

    Cassorla, V.; Rojas, X.; Gras, N.; Chuaqui, L.; Dinator, M.I.; Morales, J.R.; Llona, F.; Romo-Kroeger, C.

    1993-01-01

    Two nuclear analytical techniques, neutron activation analysis (NAA) and proton induced X-ray emission (PIXE), were used to determine major and trace elements in airborne particulate matter collected during the first fortnight of June 1991 at the La Reina Nuclear Center. NAA detected the presence of 15 elements in the samples. PIXE, for the same samples, allowed the detection of 12 elements. The elements determined by both techniques were Al, Ca, Mn, Fe, Cu, and Zn. A good correlation between results for these elements for each of the two techniques was demonstrated. (author)

  6. Cold dilute neutron matter on the lattice. II. Results in the unitary limit

    International Nuclear Information System (INIS)

    Lee, Dean; Schaefer, Thomas

    2006-01-01

    This is the second of two articles that investigate cold dilute neutron matter on the lattice using pionless effective field theory. In the unitary limit, where the effective range is zero and scattering length is infinite, simple scaling relations relate thermodynamic functions at different temperatures. When the second virial coefficient is properly tuned, we find that the lattice results obey these scaling relations. We compute the energy per particle, pressure, spin susceptibility, dineutron correlation function, and an upper bound for the superfluid critical temperature

  7. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  8. Probing Extreme-density Matter with Gravitational-wave Observations of Binary Neutron Star Merger Remnants

    Energy Technology Data Exchange (ETDEWEB)

    Radice, David [Institute for Advanced Study, 1 Einstein Drive, Princeton, NJ 08540 (United States); Bernuzzi, Sebastiano [Department of Mathematical, Physical and Computer Sciences, University of Parma, I-43124 Parma (Italy); Pozzo, Walter Del [Dipartimento di Fisica “Enrico Fermi,” Università di Pisa, Pisa I-56127 (Italy); Roberts, Luke F. [NSCL/FRIB and Department of Physics and Astronomy, Michigan State University, 640 S Shaw Lane, East Lansing, MI 48824 (United States); Ott, Christian D. [TAPIR, Walter Burke Institute for Theoretical Physics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States)

    2017-06-20

    We present a proof-of-concept study, based on numerical-relativity simulations, of how gravitational waves (GWs) from neutron star merger remnants can probe the nature of matter at extreme densities. Phase transitions and extra degrees of freedom can emerge at densities beyond those reached during the inspiral, and typically result in a softening of the equation of state (EOS). We show that such physical effects change the qualitative dynamics of the remnant evolution, but they are not identifiable as a signature in the GW frequency, with the exception of possible black hole formation effects. The EOS softening is, instead, encoded in the GW luminosity and phase and is in principle detectable up to distances of the order of several megaparsecs with advanced detectors and up to hundreds of megaparsecs with third-generation detectors. Probing extreme-density matter will require going beyond the current paradigm and developing a more holistic strategy for modeling and analyzing postmerger GW signals.

  9. Probing Extreme-density Matter with Gravitational-wave Observations of Binary Neutron Star Merger Remnants

    International Nuclear Information System (INIS)

    Radice, David; Bernuzzi, Sebastiano; Pozzo, Walter Del; Roberts, Luke F.; Ott, Christian D.

    2017-01-01

    We present a proof-of-concept study, based on numerical-relativity simulations, of how gravitational waves (GWs) from neutron star merger remnants can probe the nature of matter at extreme densities. Phase transitions and extra degrees of freedom can emerge at densities beyond those reached during the inspiral, and typically result in a softening of the equation of state (EOS). We show that such physical effects change the qualitative dynamics of the remnant evolution, but they are not identifiable as a signature in the GW frequency, with the exception of possible black hole formation effects. The EOS softening is, instead, encoded in the GW luminosity and phase and is in principle detectable up to distances of the order of several megaparsecs with advanced detectors and up to hundreds of megaparsecs with third-generation detectors. Probing extreme-density matter will require going beyond the current paradigm and developing a more holistic strategy for modeling and analyzing postmerger GW signals.

  10. Nucleation of Quark Matter in Neutron Stars:. Role of Color Superconductivity

    Science.gov (United States)

    Bombaci, Ignazio; Lugones, Germán; Vidaña, Isaac

    2008-02-01

    Pure hadronic compact stars ("neutron stars") above a critical mass Mcr are metastable1,2 for the conversion to quark stars (hybrid or strange stars). This conversion process liberates an enormous amount of energy (Econv ~ 1053 ergs), which could power some of the observed gamma ray bursts.1-3 In cold deleptonized hadronic stars, the conversion process is triggered by the quantum nucleation of a quark matter drop in the stellar center. These drops can be made up of normal (i.e. unpaired) quark matter, or color superconducting quark matter, depending on the details of the equation of state of quark and hadronic matter.4 In this talk, we present the results of recent calculations5 of the effects of color superconductivity on the conversion of hadronic stars to quark stars. In particular, we study the dependence of the critical mass Mcr and conversion energy Econv on the quark-quark pairing gap Δ, the bag constant B, and the surface tension σ of the quark-hadron interface.

  11. Paul Scherrer Institute Scientific Report 1999. Volume III: Condensed Matter Research with Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, Juerg; Castellazzi, Denise; Shea-Braun, Margit [eds.

    2000-07-01

    This year was a period of consolidation of the operation at the spallation source of PSI and its scientific exploitation at an increasing number of instruments. The major part of this annual report gives an overview of the research activities in the Laboratory of Neutron Scattering (jointly operated with the Swiss Federal Institute of Technology, ETH Zurich) of our department, mainly emphasizing highly correlated electron systems and the investigation of magnetism. The activities on multilayers and surfaces, a basic research object by itself, is however also to a large extent motivated by the development of optical components for neutron- and X-ray instrumentation. While most of the solid-state work has been done with neutrons, some contributions deal with other probes, like muons and synchrotron light, exploiting the unique possibilities at PSI, to take advantage of the complementary nature of the different probes. Progress in 1999 in these topical areas as well as the activities of the Condensed Matter Theory Group, and the Group for Low Temperature Facilities, is described in this report. A list of scientific publications in 1999 is also provided.

  12. Equation of state for dense nucleonic matter from metamodeling. II. Predictions for neutron star properties

    Science.gov (United States)

    Margueron, Jérôme; Hoffmann Casali, Rudiney; Gulminelli, Francesca

    2018-02-01

    Employing recently proposed metamodeling for the nucleonic matter equation of state, we analyze neutron star global properties such as masses, radii, momentum of inertia, and others. The impact of the uncertainty on empirical parameters on these global properties is analyzed in a Bayesian statistical approach. Physical constraints, such as causality and stability, are imposed on the equation of state and different hypotheses for the direct Urca (dUrca) process are investigated. In addition, only metamodels with maximum masses above 2 M⊙ are selected. Our main results are the following: the equation of state exhibits a universal behavior against the dUrca hypothesis under the condition of charge neutrality and β equilibrium; neutron stars, if composed exclusively of nucleons and leptons, have a radius of 12.7 ±0.4 km for masses ranging from 1 up to 2 M⊙ ; a small radius lower than 11 km is very marginally compatible with our present knowledge of the nuclear empirical parameters; and finally, the most important empirical parameters which are still affected by large uncertainties and play an important role in determining the radius of neutrons stars are the slope and curvature of the symmetry energy (Lsym and Ksym) and, to a lower extent, the skewness parameters (Qsat /sym).

  13. Paul Scherrer Institute Scientific Report 1999. Volume III: Condensed Matter Research with Neutrons

    International Nuclear Information System (INIS)

    Schefer, Juerg; Castellazzi, Denise; Shea-Braun, Margit

    2000-01-01

    This year was a period of consolidation of the operation at the spallation source of PSI and its scientific exploitation at an increasing number of instruments. The major part of this annual report gives an overview of the research activities in the Laboratory of Neutron Scattering (jointly operated with the Swiss Federal Institute of Technology, ETH Zurich) of our department, mainly emphasizing highly correlated electron systems and the investigation of magnetism. The activities on multilayers and surfaces, a basic research object by itself, is however also to a large extent motivated by the development of optical components for neutron- and X-ray instrumentation. While most of the solid-state work has been done with neutrons, some contributions deal with other probes, like muons and synchrotron light, exploiting the unique possibilities at PSI, to take advantage of the complementary nature of the different probes. Progress in 1999 in these topical areas as well as the activities of the Condensed Matter Theory Group, and the Group for Low Temperature Facilities, is described in this report. A list of scientific publications in 1999 is also provided

  14. Microscopic study of {sup 1}S{sub 0} superfluidity in dilute neutron matter

    Energy Technology Data Exchange (ETDEWEB)

    Pavlou, G.E.; Mavrommatis, E. [National and Kapodistrian University of Athens, Physics Department, Division of Nuclear and Particle Physics, Athens (Greece); Moustakidis, C. [Aristotelian University of Thessaloniki, Department of Theoretical Physics, Thessaloniki (Greece); Clark, J.W. [Washington University, McDonnell Center for the Space Sciences and Department of Physics, St. Louis, MO (United States); University of Madeira, Center for Mathematical Sciences, Funchal (Portugal)

    2017-05-15

    Singlet S-wave superfluidity of dilute neutron matter is studied within the correlated BCS method, which takes into account both pairing and short-range correlations. First, the equation of state (EOS) of normal neutron matter is calculated within the Correlated Basis Function (CBF) method in the lowest cluster order using the {sup 1}S{sub 0} and {sup 3}P components of the Argonne V{sub 18} potential, assuming trial Jastrow-type correlation functions. The {sup 1}S{sub 0} superfluid gap is then calculated with the corresponding component of the Argonne V{sub 18} potential and the optimally determined correlation functions. The dependence of our results on the chosen forms for the correlation functions is studied, and the role of the P-wave channel is investigated. Where comparison is meaningful, the values obtained for the {sup 1}S{sub 0} gap within this simplified scheme are consistent with the results of similar and more elaborate microscopic methods. (orig.)

  15. S-pairing in neutron matter: I. Correlated basis function theory

    International Nuclear Information System (INIS)

    Fabrocini, Adelchi; Fantoni, Stefano; Illarionov, Alexey Yu.; Schmidt, Kevin E.

    2008-01-01

    S-wave pairing in neutron matter is studied within an extension of correlated basis function (CBF) theory to include the strong, short range spatial correlations due to realistic nuclear forces and the pairing correlations of the Bardeen, Cooper and Schrieffer (BCS) approach. The correlation operator contains central as well as tensor components. The correlated BCS scheme of [S. Fantoni, Nucl. Phys. A 363 (1981) 381], developed for simple scalar correlations, is generalized to this more realistic case. The energy of the correlated pair condensed phase of neutron matter is evaluated at the two-body order of the cluster expansion, but considering the one-body density and the corresponding energy vertex corrections at the first order of the Power Series expansion. Based on these approximations, we have derived a system of Euler equations for the correlation factors and for the BCS amplitudes, resulting in correlated nonlinear gap equations, formally close to the standard BCS ones. These equations have been solved for the momentum independent part of several realistic potentials (Reid, Argonne v 14 and Argonne v 8 ' ) to stress the role of the tensor correlations and of the many-body effects. Simple Jastrow correlations and/or the lack of the density corrections enhance the gap with respect to uncorrelated BCS, whereas it is reduced according to the strength of the tensor interaction and following the inclusion of many-body contributions

  16. Design of a versatile detector for the detection of charged particles, neutrons and gamma rays. Neutron interaction with the matter

    International Nuclear Information System (INIS)

    Perez P, J.J.

    1991-01-01

    The Fostron detector detects charged particles, neutrons and gamma rays with a reasonable discrimination power. Because the typical detectors for neutrons present a great uncertainty in the detection, this work was focused mainly to the neutron detection in presence of gamma radiation. Also there are mentioned the advantages and disadvantages of the Fostron detector

  17. Parity-even and time-reversal-odd neutron optical potential in spinning matter induced by gravitational torsion

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, A.N., E-mail: ivanov@kph.tuwien.ac.at [Atominstitut, Technische Universität Wien, Stadionallee 2, A-1020 Wien (Austria); Snow, W.M., E-mail: wsnow@indiana.edu [Indiana University, Bloomington, IN 47408 (United States); Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408 (United States)

    2017-01-10

    Recent theoretical work has shown that spin 1/2 particles moving through unpolarized matter which sources torsion fields experience a new type of parity-even and time-reversal-odd optical potential if the matter is spinning in the lab frame. This new type of optical potential can be sought experimentally using the helicity dependence of the total cross sections for longitudinally polarized neutrons moving through a rotating cylindrical target. In combination with recent experimental constraints on short-range P-odd, T-even torsion interactions derived from polarized neutron spin rotation in matter one can derive separate constraints on the time components of scalar and pseudoscalar torsion fields in matter. We estimate the sensitivity achievable in such an experiment and briefly outline some of the potential sources of systematic error to be considered in any future experimental search for this effect.

  18. Parity-even and time-reversal-odd neutron optical potential in spinning matter induced by gravitational torsion

    Directory of Open Access Journals (Sweden)

    A.N. Ivanov

    2017-01-01

    Full Text Available Recent theoretical work has shown that spin 1/2 particles moving through unpolarized matter which sources torsion fields experience a new type of parity-even and time-reversal-odd optical potential if the matter is spinning in the lab frame. This new type of optical potential can be sought experimentally using the helicity dependence of the total cross sections for longitudinally polarized neutrons moving through a rotating cylindrical target. In combination with recent experimental constraints on short-range P-odd, T-even torsion interactions derived from polarized neutron spin rotation in matter one can derive separate constraints on the time components of scalar and pseudoscalar torsion fields in matter. We estimate the sensitivity achievable in such an experiment and briefly outline some of the potential sources of systematic error to be considered in any future experimental search for this effect.

  19. Advantage of nonlinear relativistic mean-field model in studying neutron star matter

    CERN Document Server

    Miyazaki, K

    2006-01-01

    We test the extended Zimanyi-Moszkowski model of relativistic nuclear matter for reproducing the density dependence of the symmetry energy, the direct URCA constraint M_{G}^{DU} \\geq 1.5M_{\\odot} on the gravitational mass of neutron star (NS), the large radii of NSs in RX J1856.5-3754 and qLMXB X7, the massive NSs in PSR J0751+1807 and 4U1700-37, and the baryonic mass of J0737-3039B. The two sets of NN\\rho coupling constant are considered. The first (EZM1) is the same as the Bonn A potential. The second (EZM2) is chosen so as to reproduce the symmetry energy E_s=32MeV of nuclear matter. The EZM1 can pass 6 tests among 7, while the EZM2 passes 5 tests. We can therefore conclude that the EZM model has unique and excellent features and is the most prospective one for studying the dense baryonic matter.

  20. Fast neutron spectrometry by bolometers lithium target for the reduction of background experiences of direct detection of dark matter

    International Nuclear Information System (INIS)

    Gironnet, J.

    2010-01-01

    Fast neutron spectrometry is a common interest for both direct dark matter detection and for nuclear research centres. Fast neutrons are usually detected indirectly. Neutrons are first slowed down by moderating materials for being detected in low energy range. Nevertheless, these detection techniques are and are limited in energy resolution. A new kind of fast neutron spectroscopy has been developed at the Institut d'Astrophysique Spatiale (IAS) in the aim of having a better knowledge of neutron backgrounds by the association of the bolometric technique with neutron sensitive crystals containing Li. Lithium-6 is indeed an element which has one the highest cross section for neutron capture with the 6 Li(n,α) 3 H reaction. This reaction releases 4,78 MeV tagging energetically each neutron capture. In particular for fast neutrons, the total energy measured by the bolometer would be the sum of this energy reaction and of the incoming fast neutron energy. To validate this principle, a spectrometer for fast neutrons, compact and semi-transportable, was built in IAS. This cryogenic detector, operated at 300 - 400 mK, consists of a 0.5 g LiF 95% 6 Li enriched crystal read out by a NTD-Ge sensor. This PhD thesis was on the study of the spectrometer characteristics, from the first measurements at IAS, to the measurements in the nuclear research centre of the Paul Scherrer Institute (PSI) until the final calibration with the Amande instrument of the Institut de Radioprotection et de Surete Nucleaire (IRSN). (author)

  1. On the existence of combined condensation of neutral and charged pions in neutron matter

    International Nuclear Information System (INIS)

    Muto, Takumi; Tatsumi, Toshitaka

    1987-01-01

    Combined condensation of neutral and charged pions at high-density neutron matter is studied in an approach based on the chiral symmetry. Energy density in the combined π 0 -π c condensed phase to be considered as most energetically favored is derived in a realistic calculation, where we take into account the isobar Δ (1232) degrees of freedom, baryon-baryon short-range correlations described in terms of the Landau-Migdal parameter g', and form factors in the π-baryon vertex. Characteristic features of this phase are discussed in comparison with those of the pure π 0 or the pure π c condensation. The combined π 0 -π c condensed phase sets in at baryon density (3 ∼ 5) times the nuclear density ρ 0 depending on g' after the appearance of the pure π c condensed phase. (author)

  2. Response functions of cold neutron matter: density, spin and current fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jochen; Sedrakian, Armen [Institut fuer Theoretische Physik, Goethe-Universitaet, Frankfurt am Main (Germany)

    2014-07-01

    We study the response of a single-component pair-correlated baryonic Fermi-liquid to density, spin, and their current perturbations. A complete set of response functions is calculated in the low-temperature regime. We derive the spectral functions of collective excitations associated with the density, density-current, spin, and spin-current perturbations. The dispersion relations of density and spin fluctuations are determined and it is shown that the density fluctuations lead to exciton-like undamped bound states, whereas the spin excitations correspond to diffusive modes above the pair-breaking threshold. The contribution of the collective pair-breaking modes to the specific heat of neutron matter at subnuclear densities is computed and is shown to be comparable to that of the degenerate electron gas at not too low temperatures.

  3. Globular cluster neutron stars and the determination of the dense matter equation of state

    Science.gov (United States)

    Guillot, Sebastien

    2016-09-01

    Combining measurements of the mass and radius of multiple neutron stars (NSs) represents the most promising way to determine the equation of state of dense NS matter. NSs in quiescent low-mass x-ray binaries (qLMXB) located in globular clusters have placed useful constraints on the equation of state. The statistical approaches combining measurements from multiple NSs can be further improved by the addition of more NS observations. We propose here to obtain a high signal to noise spectrum of the qLMXB in M30, the only low-absorption globular cluster qLMXBs that does not have deep X-ray observations, and which requires Chandra unmatched angular resolution. The 300 ks proposed observation will permit measurement of the NS radius with 12-15% uncertainties.

  4. Collection of size fractionated particulate matter sample for neutron activation analysis in Japan

    International Nuclear Information System (INIS)

    Otoshi, Tsunehiko; Nakamatsu, Hiroaki; Oura, Yasuji; Ebihara, Mitsuru

    2004-01-01

    According to the decision of the 2001 Workshop on Utilization of Research Reactor (Neutron Activation Analysis (NAA) Section), size fractionated particulate matter collection for NAA was started from 2002 at two sites in Japan. The two monitoring sites, ''Tokyo'' and ''Sakata'', were classified into ''urban'' and ''rural''. In each site, two size fractions, namely PM 2-10 '' and PM 2 '' particles (aerodynamic particle size between 2 to 10 micrometer and less than 2 micrometer, respectively) were collected every month on polycarbonate membrane filters. Average concentrations of PM 10 (sum of PM 2-10 and PM 2 samples) during the common sampling period of August to November 2002 in each site were 0.031mg/m 3 in Tokyo, and 0.022mg/m 3 in Sakata. (author)

  5. Probing the neutron star interior and the Equation of State of cold dense matter with the SKA

    NARCIS (Netherlands)

    Watts, A.; Xu, R.; Espinoza, C.; Andersson, N.; Antoniadis, J.; Antonopoulou, D.; Buchner, S.; Dai, S.; Demorest, P.; Freire, P.; Hessels, J.; Margueron, J.; Oertel, M.; Patruno, A.; Possenti, A.; Ransom, S.; Stairs, I.; Stappers, B.

    2015-01-01

    With an average density higher than the nuclear density, neutron stars (NS) provide a unique testground for nuclear physics, quantum chromodynamics (QCD), and nuclear superfluidity. Determination of the fundamental interactions that govern matter under such extreme conditions is one of the major

  6. Constraining properties of high-density matter in neutron stars with magneto-elastic oscillations

    Science.gov (United States)

    Gabler, Michael; Cerdá-Durán, Pablo; Stergioulas, Nikolaos; Font, José A.; Müller, Ewald

    2018-05-01

    We discuss torsional oscillations of highly magnetized neutron stars (magnetars) using two-dimensional, magneto-elastic-hydrodynamical simulations. Our model is able to explain both the low- and high-frequency quasi-periodic oscillations (QPOs) observed in magnetars. The analysis of these oscillations provides constraints on the breakout magnetic-field strength, on the fundamental QPO frequency, and on the frequency of a particularly excited overtone. By performing a new set of simulations, we are able to derive for the first time empirical relations for a self consistent model including a superfluid core which describe these constraints quantitatively. We use these relations to generically constrain properties of high-density matter in neutron stars, employing Bayesian analysis. In spite of current uncertainties and computational approximations, our model-dependent Bayesian posterior estimates for SGR 1806-20 yield a magnetic-field strength \\bar{B}˜ 2.1^{+1.3}_{-1.0}× 10^{15} G and a crust thickness of Δ r = 1.6^{+0.7}_{-0.6} km, which are both in remarkable agreement with observational and theoretical expectations, respectively (1σ error bars are indicated). Our posteriors also favour the presence of a superfluid phase in the core, a relatively low stellar compactness, M/R star, and high shear speeds at the base of the crust, cs > 1.4 × 108 cm s-1. Although the procedure laid out here still has large uncertainties, these constraints could become tighter when additional observations become available.

  7. Comparison of neutron activation analysis with other instrumental methods for elemental analysis of airborne particulate matter

    International Nuclear Information System (INIS)

    Regge, P. de; Lievens, F.; Delespaul, I.; Monsecour, M.

    1976-01-01

    A comparison of instrumental methods, including neutron activation analysis, X-ray fluorescence spectrometry, atomic absorption spectrometry and emission spectrometry, for the analysis of heavy metals in airborne particulate matter is described. The merits and drawbacks of each method for the routine analysis of a large number of samples are discussed. The sample preparation technique, calibration and statistical data relevant to each method are given. Concordant results are obtained by the different methods for Co, Cu, Ni, Pb and Zn. Less good agreement is obtained for Fe, Mn and V. The results are not in agreement for the elements Cd and Cr. Using data obtained on the dust sample distributed by Euratom-ISPRA within the framework of an interlaboratory comparison, the accuracy of each method for the various elements is estimated. Neutron activation analysis was found to be the most sensitive and accurate of the non-destructive analysis methods. Only atomic absorption spectrometry has a comparable sensitivity, but requires considerable preparation work. X-ray fluorescence spectrometry is less sensitive and shows biases for Cr and V. Automatic emission spectrometry with simultaneous measurement of the beam intensities by photomultipliers is the fastest and most economical technique, though at the expense of some precision and sensitivity. (author)

  8. Accretion of matter onto highly magnetized neutron stars: Final report, July 1-September 30, 1985

    International Nuclear Information System (INIS)

    Hernquist, L.

    1986-06-01

    A final report is given of two research projects dealing with magnetic fields of neutron stars. These are the modulation of thermal x-rays from cooling neutron stars and plasma instabilities in neutron star accretion columns

  9. On the properties of nuclear matter with an excess of neutrons, spin-up neutrons and spin-up protons using effective nucleon-nucleon potential

    International Nuclear Information System (INIS)

    Hassan, M.Y.; Ramadan, S.

    1978-01-01

    The binding energy of nuclear matter with an excess of neutrons, with spin-up neutrons and spin-up protons (characterized by the corresponding parameters αsub(tau)=(N-Z)/A, αsub(n)=(N(up)-N(down))/A, and αsub(p)=(Z(up)-Z(down))/A) contains three symmetry energies: the isospin symmetry energy epsilon sub(tau), the spin symmetry energy epsilon sub(sigma) and the spin-isospin symmetry energy epsilon sub(sigma tau). These energies are calculated using velocity-dependent effective potential of s-wave interaction, which was developed by Dzhibuti and Mamasakhlisov. The spin, isospin and spin-isospin dependent parts of the single-particle potential in nuclear matter are also calculated using the same effective nucleon-nucleon potentials. The spin-spin part of the optical model potential is estimated. (author)

  10. Shear viscosity of neutron-rich nucleonic matter near its liquid–gas phase transition

    International Nuclear Information System (INIS)

    Xu, Jun; Chen, Lie-Wen; Ko, Che Ming; Li, Bao-An; Ma, Yu Gang

    2013-01-01

    Within a relaxation time approach using free nucleon–nucleon cross sections modified by the in-medium nucleon masses that are determined from an isospin- and momentum-dependent effective nucleon–nucleon interaction, we investigate the specific shear viscosity (η/s) of neutron-rich nucleonic matter near its liquid–gas phase transition. It is found that as the nucleonic matter is heated at fixed pressure or compressed at fixed temperature, its specific shear viscosity shows a valley shape in the temperature or density dependence, with the minimum located at the boundary of the phase transition. Moreover, the value of η/s drops suddenly at the first-order liquid–gas phase transition temperature, reaching as low as 4–5 times the KSS bound of ℏ/4π. However, it varies smoothly for the second-order liquid–gas phase transition. Effects of the isospin degree of freedom and the nuclear symmetry energy on the value of η/s are also discussed

  11. Characterisation of air particulate matter in Klang Valley by neutron activation analysis technique

    International Nuclear Information System (INIS)

    Mohd Suhaimi Hamzah; Shamsiah Abd Rahman; Mohd Khalid Matori; Abd Khalik Wood

    2000-01-01

    Air particulate matter is known to affect human health, impairs visibility and can cause climate change. Study on air particulate matter in term of particle size and chemical contents is very important to indicate the quality of air in a sampling area. Information on concentration of important constituents in air particles can be used to identify some of emission sources which contribute to the pollution problem. The data collected may also be, used as a basis to design a strategy in order to overcome the air pollution problem in the area. The study involved sampling of air dust at two stations, one in Bangi and the other in Kuala Lumpur using Gent Stack Sampler units. Each sampler capable of collecting air particle sizes smaller than 2.5 micron (PM 2.5) and between 2.5 - O micron on two different filters simultaneously. The filters were measured for their mass, elemental carbon and elemental concentrations using analytical equipment or techniques including reflectometer and Neutron Activation Analysis. The results of analysis on samples collected in 1997-1998 are discussed. (author)

  12. Properties of nuclear and neutron matter in a relativistic Hartree-Fock theory

    International Nuclear Information System (INIS)

    Horowitz, C.J.; Serot, B.D.

    1983-01-01

    Relativistic-Hartree-Fock (HF) equations are derived for an infinite system of mesons and baryons in the framework of a renormalizable relativistic quantum field theory. The derivation is based on a diagrammatic approach and Dyson's equation for the baryon propagator. The result is a set of coupled, nonlinear integral equations for the baryon self-energy with a self-consistency condition on the single-particle spectrum. The HF equations are solved for nuclear and neutron matter in the Walecka model, which contains neutral scalar and vector mesons. After renormalizing model parameters to reproduce nuclear matter saturation properties, HF results at low to moderate densities are similar to those in the mean-field (Hartree) approximation. Self-consistent exchange corrections to the Hartree equation of state become negligible at high densities. Rho- and pi-meson exchanges are incorporated using a renormalizable gauge-theory model. A chiral transformation of the lagrangian is used to replace the pseudoscalar πN coupling with a pseudovector coupling, for which one-pion exchange is a reasonable first approximation. This transformation maintains the model's renormalizability so that corrections may be evaluated. Pion exchange has a small effect on the HF results of the Walecka model and brings HF results in closer in closer agreement with the mean-field theory. The diagrammatic techniques used here retain the mesonic degrees of freedom and are simple enough to be extended to more refined self-consistent approximations. (orig.)

  13. Sampling and analytical methodologies for instrumental neutron activation analysis of airborne particulate matter

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-01

    The IAEA supports a number of projects having to do with the analysis of airborne particulate matter by nuclear techniques. Most of this work involves the use of activation analysis in its various forms, particularly instrumental neutron activation analysis (INAA). This technique has been widely used in many different countries for the analysis of airborne particulate matter, and there are already many publications in scientific journals, books and reports describing such work. The present document represents an attempt to summarize the most important features of INAA as applied to the analysis of airborne particulate matter. It is intended to serve as a set of guidelines for use by participants in the IAEA's own programmes, and other scientists, who are not yet fully experienced in the application of INAA to airborne particulate samples, and who wish either to make a start on using this technique or to improve their existing procedures. The methodologies for sampling described in this document are of rather general applicability, although they are presented here in a way that takes account of the particular requirements arising from the use of INAA as the analytical technique. The analytical part of the document, however, is presented in a form that is applicable only to INAA. (Subsequent publications in this series are expected to deal specifically with other nuclear related techniques such as energy dispersive X ray fluorescence (ED-XRF) and particle induced X ray emission (PIXE) analysis). Although the methods and procedures described here have been found through experience to yield acceptable results, they should not be considered mandatory. Any other procedure used should, however, be chosen to be capable of yielding results at least of equal quality to those described.

  14. Sampling and analytical methodologies for instrumental neutron activation analysis of airborne particulate matter

    International Nuclear Information System (INIS)

    1992-01-01

    The IAEA supports a number of projects having to do with the analysis of airborne particulate matter by nuclear techniques. Most of this work involves the use of activation analysis in its various forms, particularly instrumental neutron activation analysis (INAA). This technique has been widely used in many different countries for the analysis of airborne particulate matter, and there are already many publications in scientific journals, books and reports describing such work. The present document represents an attempt to summarize the most important features of INAA as applied to the analysis of airborne particulate matter. It is intended to serve as a set of guidelines for use by participants in the IAEA's own programmes, and other scientists, who are not yet fully experienced in the application of INAA to airborne particulate samples, and who wish either to make a start on using this technique or to improve their existing procedures. The methodologies for sampling described in this document are of rather general applicability, although they are presented here in a way that takes account of the particular requirements arising from the use of INAA as the analytical technique. The analytical part of the document, however, is presented in a form that is applicable only to INAA. (Subsequent publications in this series are expected to deal specifically with other nuclear related techniques such as energy dispersive X ray fluorescence (ED-XRF) and particle induced X ray emission (PIXE) analysis). Although the methods and procedures described here have been found through experience to yield acceptable results, they should not be considered mandatory. Any other procedure used should, however, be chosen to be capable of yielding results at least of equal quality to those described

  15. Confinement of quasi-particles in a condensed matter system: an inelastic neutron scattering study

    International Nuclear Information System (INIS)

    Bera, A.K.

    2016-01-01

    The confinement of quasi particles, a well-known phenomenon in particle physics, can also be realized in a condensed matter system. In particle physics, baryons and mesons are produced by the confinement of quarks, where quarks are bound together by a strong interaction (gauge field) that grows stronger with increasing distance and, therefore, the quarks never exist as individual particles. The condensed matter analogue, confinement of magnetic quasiparticles (spinons) can be illustrated in quasi-one-dimensional spin-1/2 chains. We demonstrate experimentally such spinon confinement in the weakly coupled spin-1/2 XXZ antiferromagnetic chain compound SrCo_2V_2O_8 by single crystal inelastic neutron scattering. The compound SrCo_2V_2O_8 belongs to the general family SrM_2V_2O_8 (M = Ni, Co and Mn), having four-fold screw chains of edge sharing MO_6 octahedra along the crystallographic c axis. In the pure 1D magnetic state of SrCo_2V_2O_8 (above the 3D magnetic ordering temperature T_N =5 K) two spinons (excitations of individual chains) are created by a spin flip, and those spinons propagate independently by subsequent spin flips without any cost of energy. However, below the T_N, two spinons are bound together by weak interchain interactions since the separation between them frustrates the interchain interactions. The interchain interactions play the role of an attractive potential (equivalent to the gauge field), proportional to the distance between spinons, and result in confinement of spinons into bound pairs. (author)

  16. Nuclear ``pasta'' structures in low-density nuclear matter and properties of the neutron-star crust

    Science.gov (United States)

    Okamoto, Minoru; Maruyama, Toshiki; Yabana, Kazuhiro; Tatsumi, Toshitaka

    2013-08-01

    In the neutron-star crust, nonuniform structure of nuclear matter—called the “pasta” structure—is expected. From recent studies of giant flares in magnetars, these structures might be related to some observables and physical quantities of the neutron-star crust. To investigate the above quantities, we numerically explore the pasta structure with a fully three-dimensional geometry and study the properties of low-density nuclear matter, based on the relativistic mean-field model and the Thomas-Fermi approximation. We observe typical pasta structures for fixed proton number fraction and two of them for cold catalyzed matter. We also discuss the crystalline configuration of “pasta.”

  17. Investigation of static and dynamic properties of condensed matter by using neutron scattering

    International Nuclear Information System (INIS)

    Davidovic, M.

    1997-01-01

    Possibilities of using neutron scattering for investigating microscopic properties of materials are analyzed. Basic neutron scattering theory is presented and its use in structure and dynamics analyses of condense systems. (author)

  18. Neutron stars, fast pulsars, supernovae and the equation of state of dense matter

    International Nuclear Information System (INIS)

    Glendening, N.K.

    1989-01-01

    We discuss the prospects for obtaining constraints on the equation of state from astrophysical sources. Neutron star masses although few are known at present, provide a very direct constraint in as much as the connection to the equation of state involves only the assumption that Einstein's general theory of relativity is correct at the macroscopic scale. If the millisecond pulses briefly observed in the remnant of SN1987A can be attributed to uniform rotation of a pulsar, then a very severe constraint is placed on the equation of state. The theory again is very secure. The precise nature of the constraint is not yet understood, but it appears that the equation of state must be neither too soft nor stiff, and it may be that there is information not only on the stiffness of the equation of state but on its shape. Supernovae simulations involve such a plethora of physical processes including those involved in the evolution of the precollapse configuration, not all of them known or understood, that they provide no constraint at the present time. Not even the broad category of mechanism for the explosion is agreed upon (prompt shock, delayed shock, or nuclear explosion). In connection with very fast pulsars, we include some speculations on pure quark matter stars, and on possible scenarios for understanding the disappearance of the fast pulsar in SN1987A. 47 refs., 16 figs., 1 tab

  19. Testing universal relations of neutron stars with a nonlinear matter-gravity coupling theory

    International Nuclear Information System (INIS)

    Sham, Y.-H.; Lin, L.-M.; Leung, P. T.

    2014-01-01

    Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different physical quantities of NSs can exist. Lau et al. found that the frequency of the f-mode oscillation, the mass, and the moment of inertia are connected by universal relations. More recently, Yagi and Yunes discovered the I-Love-Q universal relations among the mass, the moment of inertia, the Love number, and the quadrupole moment. In this paper, we study these universal relations in the Eddington-inspired Born-Infeld (EiBI) gravity. This theory differs from general relativity (GR) significantly only at high densities due to the nonlinear coupling between matter and gravity. It thus provides us an ideal case to test how robust the universal relations of NSs are with respect to the change of the gravity theory. Due to the apparent EOS formulation of EiBI gravity developed recently by Delsate and Steinhoff, we are able to study the universal relations in EiBI gravity using the same techniques as those in GR. We find that the universal relations in EiBI gravity are essentially the same as those in GR. Our work shows that, within the currently viable coupling constant, there exists at least one modified gravity theory that is indistinguishable from GR in view of the unexpected universal relations.

  20. Testing Universal Relations of Neutron Stars with a Nonlinear Matter-Gravity Coupling Theory

    Science.gov (United States)

    Sham, Y.-H.; Lin, L.-M.; Leung, P. T.

    2014-02-01

    Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different physical quantities of NSs can exist. Lau et al. found that the frequency of the f-mode oscillation, the mass, and the moment of inertia are connected by universal relations. More recently, Yagi and Yunes discovered the I-Love-Q universal relations among the mass, the moment of inertia, the Love number, and the quadrupole moment. In this paper, we study these universal relations in the Eddington-inspired Born-Infeld (EiBI) gravity. This theory differs from general relativity (GR) significantly only at high densities due to the nonlinear coupling between matter and gravity. It thus provides us an ideal case to test how robust the universal relations of NSs are with respect to the change of the gravity theory. Due to the apparent EOS formulation of EiBI gravity developed recently by Delsate and Steinhoff, we are able to study the universal relations in EiBI gravity using the same techniques as those in GR. We find that the universal relations in EiBI gravity are essentially the same as those in GR. Our work shows that, within the currently viable coupling constant, there exists at least one modified gravity theory that is indistinguishable from GR in view of the unexpected universal relations.

  1. Neutron stars, fast pulsars, supernovae and the equation of state of dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Glendening, N.K.

    1989-06-01

    We discuss the prospects for obtaining constraints on the equation of state from astrophysical sources. Neutron star masses although few are known at present, provide a very direct constraint in as much as the connection to the equation of state involves only the assumption that Einstein's general theory of relativity is correct at the macroscopic scale. If the millisecond pulses briefly observed in the remnant of SN1987A can be attributed to uniform rotation of a pulsar, then a very severe constraint is placed on the equation of state. The theory again is very secure. The precise nature of the constraint is not yet understood, but it appears that the equation of state must be neither too soft nor stiff, and it may be that there is information not only on the stiffness of the equation of state but on its shape. Supernovae simulations involve such a plethora of physical processes including those involved in the evolution of the precollapse configuration, not all of them known or understood, that they provide no constraint at the present time. Not even the broad category of mechanism for the explosion is agreed upon (prompt shock, delayed shock, or nuclear explosion). In connection with very fast pulsars, we include some speculations on pure quark matter stars, and on possible scenarios for understanding the disappearance of the fast pulsar in SN1987A. 47 refs., 16 figs., 1 tab.

  2. Recent Progress in Constraining the Equation of State of Dense Neutron-Rich Nuclear Matter with Heavy-Ion Reactions

    International Nuclear Information System (INIS)

    Li Baoan; Chen Liewen; Wen Dehua; Xiao Zhigang; Xu Chang; Yong Gaochan; Zhang Ming

    2010-01-01

    The nuclear symmetry energy E sym (ρ) is the most uncertain part of the Equation of State (EOS) of dense neutron-rich nuclear matter. In this talk, we discuss the underlying physics responsible for the uncertain E sym (ρ) especially at supra-saturation densities, the circumstantial evidence for a super-soft E sym (ρ) from analyzing π - /π + ratio in relativistic heavy-ion collisions and its impacts on astrophysics and cosmology.

  3. Tidal capture of a primordial black hole by a neutron star: implications for constraints on dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Pani, Paolo [CENTRA, Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais 1, Lisboa, 1049 Portugal (Portugal); Loeb, Abraham, E-mail: paolo.pani@tecnico.ulisboa.pt, E-mail: aloeb@cfa.harvard.edu [Institute for Theory and Computation, Harvard-Smithsonian CfA, 60 Garden Street, Cambridge, MA, 02138 (United States)

    2014-06-01

    In a close encounter with a neutron star, a primordial black hole can get gravitationally captured by depositing a considerable amount of energy into nonradial stellar modes of very high angular number l. If the neutron-star equation of state is sufficiently stiff, we show that the total energy loss in the point-particle approximation is formally divergent. Various mechanisms — including viscosity, finite-size effects and the elasticity of the crust — can damp high-l modes and regularize the total energy loss. Within a short time, the black hole is trapped inside the star and disrupts it by rapid accretion. Estimating these effects, we predict that the existence of old neutron stars in regions where the dark-matter density ρ{sub DM}∼>10{sup 2}(σ/km s{sup −1}) GeV cm{sup −3} (where σ is the dark-matter velocity dispersion) limits the abundance of primordial black holes in the mass range 10{sup 17} g∼matter constituent.

  4. I. Nuclear and neutron matter calculations with isobars. II. A model calculation of Fermi liquid parameters for liquid 3He

    International Nuclear Information System (INIS)

    Ainsworth, T.L.

    1983-01-01

    The Δ(1232) plays an important role in determining the properties of nuclear and neutron matter. The effects of the Δ resonance are incorporated explicitly by using a coupled channel formalism. A method for constraining a lowest order variational calculation, appropriate when nucleon internal degrees of freedom are made explicity, is presented. Different N-N potentials were calculated and fit to phase shift data and deuteron properties. The potentials were constructed to test the relative importance of the Δ resonance on nuclear properties. The symmetry energy and incompressibility of nuclear matter are generally reproduced by this calculation. Neutron matter results lead to appealing neutron star models. Fermi liquid parameters for 3 He are calculated with a model that includes both direct and induced terms. A convenient form of the direct interaction is obtained in terms of the parameters. The form of the direct interaction ensures that the forward scattering sum rule (Pauli principle) is obeyed. The parameters are adjusted to fit the experimentally determined F 0 /sup s/, F 0 /sup a/, and F 1 /sup s/ Landau parameters. Higher order Landau parameters are calculated by the self-consistent solution of the equations; comparison to experiment is good. The model also leads to a preferred value for the effective mass of 3 He. Of the three parameters only one shows any dependence on pressure. An exact sum rule is derived relating this parameter to a specific summation of Landau parameters

  5. On the properties of nuclear matter with an excess of neutrons, of spin-up neutrons and of spin-up protons using the Skyrme interaction

    International Nuclear Information System (INIS)

    Hassan, M.Y.M.; Ramadan, S.

    1983-11-01

    The binding energy of nuclear matter with an excess of neutrons, of spin-up neutrons, and of spin-up protons (characterized by the corresponding parameters, αsub(tau)=(N-Z/A), αsub(n)=(Nup-Ndown)/A, and αsub(rho)=(Zup-Zdown)/A), contains three symmetry energies: the isospin symmetry energy Esub(tau), the spin symmetry energy Esub(σ), and spin-isospin symmetry energy Esub(σtau). General expressions for Esub(σ), Esub(tau) and Esub(σtau) are given in the case of the Skyrme interaction. These values are compared with previous results obtained by Dabrowski and Haensel (DH) with Brueckner-Gammel-Thaler, the Hamada-Johnston, and the Reid soft core nucleon-nucleon potentials. The spin, isospin and spin-isospin dependent parts of the single-particle potential in nuclear matter are also calculated using the Skyrme interaction. The spin, isospin and spin-isospin incompressibility are calculated using the Skyrme interaction. The spin-spin part of the optical model potential is estimated. The results are compared with those of Dabrowski and Haensel (DH) and Hassan and Ramadan. (author)

  6. Asymmetry of neutrino emission from neutron beta-decay in superdense matter and strong magnetic field

    International Nuclear Information System (INIS)

    Kauts, V.L.; Savochkin, A.M.; Studenikin, A.I.

    2006-01-01

    Exact solution of Dirac equation for charged particles in homogenous magnetic field for computation of probability in presence of degenerate magnetized Fermi-gas consisting of protons, neutrons, and electrons has been used. Angular distribution of antineutrino momenta is investigated. Values of main parameters of medium is realistic for physics of neutron stars. This investigation may be applied for consideration of cooling of neutron stars [ru

  7. Simulations of the muon-induced neutron background of the EDELWEISS-II experiment for Dark Matter search

    International Nuclear Information System (INIS)

    Horn, O.M.

    2007-01-01

    In modern astroparticle physics and cosmology, the nature of Dark Matter is one of the central problems. Particle Dark Matter in form of WIMPs is favoured among many proposed candidates. The EDELWEISS direct Dark Matter search uses Germanium bolometers to detect these particles by nuclear recoils. Here, the use of two signal channels on an event-by-event basis, namely the heat and ionisation signal, enables the detectors to discriminate between electron and nuclear recoils. This technique leaves neutrons in the underground laboratory as the main background for the experiment. Besides (α,n) reactions of natural radioactivity, neutrons are produced in electromagnetic and hadronic showers induced by cosmic ray muons in the surrounding rock and shielding material of the Germanium crystals. To reach high sensitivities, the EDELWEISS-II experiment, as well as other direct Dark Matter searches, has to efficiently suppress this neutron background. The present work is devoted to study the muon-induced neutron flux in the underground laboratory LSM and the interaction rate within the Germanium crystals by using the Monte Carlo simulation toolkit Geant4. To ensure reliable results, the implemented physics in the toolkit regarding neutron production is tested in a benchmark geometry and results are compared to experimental data and other simulation codes. Also, the specific energy and angular distribution of the muon flux in the underground laboratory as a consequence of the asymmetric mountain overburden is implemented. A good agreement of the simulated muon flux is shown in a comparison to preliminary experimental data obtained with the EDELWEISS-II muon veto system. Furthermore, within a detailed geometry of the experimental setup, the muon-induced background rate of nuclear recoils in the bolometers is simulated. Coincidences of recoil events in the Germanium with an energy deposit of the muoninduced shower in the plastic scintillators of the veto system are studied to

  8. Simulations of the muon-induced neutron background of the EDELWEISS-II experiment for Dark Matter search

    Energy Technology Data Exchange (ETDEWEB)

    Horn, O M

    2007-12-21

    In modern astroparticle physics and cosmology, the nature of Dark Matter is one of the central problems. Particle Dark Matter in form of WIMPs is favoured among many proposed candidates. The EDELWEISS direct Dark Matter search uses Germanium bolometers to detect these particles by nuclear recoils. Here, the use of two signal channels on an event-by-event basis, namely the heat and ionisation signal, enables the detectors to discriminate between electron and nuclear recoils. This technique leaves neutrons in the underground laboratory as the main background for the experiment. Besides ({alpha},n) reactions of natural radioactivity, neutrons are produced in electromagnetic and hadronic showers induced by cosmic ray muons in the surrounding rock and shielding material of the Germanium crystals. To reach high sensitivities, the EDELWEISS-II experiment, as well as other direct Dark Matter searches, has to efficiently suppress this neutron background. The present work is devoted to study the muon-induced neutron flux in the underground laboratory LSM and the interaction rate within the Germanium crystals by using the Monte Carlo simulation toolkit Geant4. To ensure reliable results, the implemented physics in the toolkit regarding neutron production is tested in a benchmark geometry and results are compared to experimental data and other simulation codes. Also, the specific energy and angular distribution of the muon flux in the underground laboratory as a consequence of the asymmetric mountain overburden is implemented. A good agreement of the simulated muon flux is shown in a comparison to preliminary experimental data obtained with the EDELWEISS-II muon veto system. Furthermore, within a detailed geometry of the experimental setup, the muon-induced background rate of nuclear recoils in the bolometers is simulated. Coincidences of recoil events in the Germanium with an energy deposit of the muoninduced shower in the plastic scintillators of the veto system are studied

  9. Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly

    Directory of Open Access Journals (Sweden)

    Yakhshiev U.T.

    2010-04-01

    Full Text Available The neutron-proton mass difference in (isospin asymmetric nuclear matter and finite nuclei is studied in the framework of a medium-modified Skyrme model. The proposed effective Lagrangian incorporates both the medium influence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking effect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it markedly decreases in neutron matter. Furthermore, the possible interplay between the effective nucleon mass in finite nuclei and the Nolen-Schiffer anomaly is discussed. In particular, we find that a correct description of the properties of mirror nuclei leads to a stringent restriction of possible modifications of the nucleon’s effective mass in nuclei.

  10. Modern trends in position-sensitive neutron detectors development for condensed matter research

    International Nuclear Information System (INIS)

    Belushkin, A.V.

    2007-01-01

    Detecting neutrons is a more complicated task compared to the detection of ionizing particles or ionizing radiation. This is why the variety of neutron detectors is much more limited. Meanwhile, different types of neutron experiments pose specific and often contradictory requirements for detector characteristics. For experiments on the high-intensity neutron sources, the high counting rate is one of the key issues. This is very important, for example, for small-angle neutron scattering and neutron reflectometry. For other experiments, characteristics like detection efficiency, high position resolution, high time resolution, neutron/gamma discrimination, large-area imaging, or compactness, are very important. Today, the cost of the detector also became one of the most important factors. There is no single type of detector which satisfies all the above criteria. Therefore, compromise is inevitable and some of the characteristics are trade off in favor of others. The present report gives an overview of detector systems presently operating at the leading neutron scattering facilities as well as some development work around the globe

  11. Tool for the study of matter - the spallation neutron source. Werkzeug zur Erforschung der Materie - die Spallations-Neutronenquelle

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    It deals with the optimal use of a whole series of matter penetrating radiation types at the construction of a spallation neutron source which the Kernforschungsanlage Juelich will realize in agreement with its associated. This new big science device for the fundamental research in the Federal Republic of Germany shall as the most modern and intense source of neutrons, protons, pions, muons, and neutrinos permits to proceed in the fields of solid state physics, chemistry, molecular biology, intermediate-energy nuclear physics, radiochemistry and radiopharmacology, medicine, and materials science to virgin territory and to provide top research. All interested German groups of researchers and also scientists of foreign countries shall be able to work with this directive big science device.

  12. Moment of inertia, quadrupole moment, Love number of neutron star and their relations with strange-matter equations of state

    Science.gov (United States)

    Bandyopadhyay, Debades; Bhat, Sajad A.; Char, Prasanta; Chatterjee, Debarati

    2018-02-01

    We investigate the impact of strange-matter equations of state involving Λ hyperons, Bose-Einstein condensate of K- mesons and first-order hadron-quark phase transition on moment of inertia, quadrupole moment and tidal deformability parameter of slowly rotating neutron stars. All these equations of state are compatible with the 2 M_{solar} constraint. The main findings of this investigation are the universality of the I- Q and I -Love number relations, which are preserved by the EoSs including Λ hyperons and antikaon condensates, but broken in the presence of a first-order hadron-quark phase transition. Furthermore, it is also noted that the quadrupole moment approaches the Kerr value of a black hole for maximum-mass neutron stars.

  13. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J.

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  14. Time projection chambers with integrated pixels and their application to fast neutron detection and dark matter searches

    Energy Technology Data Exchange (ETDEWEB)

    Seong, I.S., E-mail: issung83@gmail.com; Beamer, K.; Hedges, M.T.; Jaegle, I.; Rosen, M.D.; Ross, S.J.; Thorpe, T.N.; Vahsen, S.E.; Yamaoka, J.

    2013-12-21

    We present our most recent work on the use of integrated silicon pixel electronics to read out gas-filled Time Projection Chambers (TPCs). Such detectors have great promise to measure the direction and energy of neutral particles via nuclear recoils that ionize the gas. We report on ongoing studies and refinement of the first prototype constructed at the University of Hawaii. We present data on the detection of alpha particles and fast neutrons using Ar:CO{sub 2} (70:30) and He:CO{sub 2} (70:30) gas, respectively. We also present plans and sensitivity estimates for a future Dark Matter search based on the technology under study.

  15. A simple testable model of baryon number violation: Baryogenesis, dark matter, neutron-antineutron oscillation and collider signals

    Science.gov (United States)

    Allahverdi, Rouzbeh; Dev, P. S. Bhupal; Dutta, Bhaskar

    2018-04-01

    We study a simple TeV-scale model of baryon number violation which explains the observed proximity of the dark matter and baryon abundances. The model has constraints arising from both low and high-energy processes, and in particular, predicts a sizable rate for the neutron-antineutron (n - n bar) oscillation at low energy and the monojet signal at the LHC. We find an interesting complementarity among the constraints arising from the observed baryon asymmetry, ratio of dark matter and baryon abundances, n - n bar oscillation lifetime and the LHC monojet signal. There are regions in the parameter space where the n - n bar oscillation lifetime is found to be more constraining than the LHC constraints, which illustrates the importance of the next-generation n - n bar oscillation experiments.

  16. Computational methods for the nuclear and neutron matter problems: Final report

    International Nuclear Information System (INIS)

    Kalos, M.H.; Chen, J.M.C.

    1988-01-01

    This paper discusses the following topics: variational Monte Carlo study of oxygen 16; microscopic calculations of alpha-neutron scattering; exact Monte Carlo treatment of the fermion problem; and random field method

  17. Study of the Condensed Matter Dynamics by the Deep Inelastic Neutron Technique

    International Nuclear Information System (INIS)

    Blostein, Juan Jeronimo

    2004-01-01

    physical phenomena.For the special case of light water/ heavy water mixtures we present calculations that reproduce the behavior of the reported anomalies on the hydrogen-deuterium neutron cross section rate.We present total cross section measurements of such liquid mixtures, in total agreement with the expected values, whereby we conclude that the purported anomalous cross sections (reported after employing the convolution approximation in the eVS data treatment) do not exist.The absence of anomalies in the total cross sections of those liquid mixtures provides a clear evidence of the invalidity of the convolution formalism usually employed in the eVS data treatment. In view of the main motivation that originated the eVS technique, and the clear invalidity of the convolution formalism, we present for the first time the exact formalism to obtain the nuclear impulse distributions in condensed matter systems, starting form the experimentally observed intensity profiles.Such formalism, valid for an arbitrary impulse distribution, does not require the harmonic potential hypothesis, and involves an integration kernel that depends analytically only on the instrumental characteristics, and is independent of the sample characteristics. Our work, besides assessing the magnitude of the inaccuracy of the convolution formalism, establishes the basis for a correct treatment of the experimental data obtained with this technique.On the experimental side, we implemented successfully the eVS technique in the linear accelerator pulsed neutron facility at the Bariloche Atomic Center, thus being the second laboratory in the world to employ it regularly.Monte Carlo simulation presented in this thesis, show the importance to adequately select the sample thickness, and to correct by multiple scattering, attenuation and detector efficiency effects, and also to employ the exact formalism.To this end it is necessary to characterize in detail the different elements that compose the experimental

  18. Neutron techniques

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1986-01-01

    The way in which neutrons interact with matter such as slowing-down, diffusion, neutron absorption and moderation are described. The use of neutron techniques in industry, in moisture gages, level and interface measurements, the detection of blockages, boron analysis in ore feedstock and industrial radiography are discussed. (author)

  19. Paul Scherrer Institut Scientific Report 2001. Volume III: Condensed Matter Research with Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, J; Castellazzi, D; Shea-Braun, M [eds.

    2002-03-01

    The SINQ-facility stopped operation at the end of the year 2001 for the scheduled shut down. By that time the spallation target of the 'Cannelloni'-type (D{sub 2}O-cooled steel pins filled with lead) had received a total charge of more then 10 Ah at an average proton current higher than 1 mA. Thereby nearly 4 mols of neutrons had been released from this target. The two operational years with this target delivered the neutrons for about 300 experiments. During this operational period not one single interrupt caused by the spallation target has been recorded -indeed a convincing evidence for the reliability of this system. The probes inserted into the target and some of its parts will now soon be available to the materials scientists for careful investigation. SINQ as a continuous spallation neutron source was considered to be a 'high risk' project. Furthermore it was often accompanied with the suspicion to represent the 'worst of two worlds' - meaning that this facility would suffer from the disadvantages but not benefit from the advantage of a spallation neutron source - the pulse structure. According to our operational experience these fears are not justified provided the various concerns have been properly taken into consideration during design and construction. This report testifies what can be achieved at a continuous spallation neutron source. We believe that these research activities compare well with those from a beam-tube reactor of medium flux. A list of scientific publications in 2000 is also provided.

  20. Paul Scherrer Institut Scientific Report 2001. Volume III: Condensed Matter Research with Neutrons

    International Nuclear Information System (INIS)

    Schefer, J.; Castellazzi, D.; Shea-Braun, M.

    2002-03-01

    The SINQ-facility stopped operation at the end of the year 2001 for the scheduled shut down. By that time the spallation target of the 'Cannelloni'-type (D 2 O-cooled steel pins filled with lead) had received a total charge of more then 10 Ah at an average proton current higher than 1 mA. Thereby nearly 4 mols of neutrons had been released from this target. The two operational years with this target delivered the neutrons for about 300 experiments. During this operational period not one single interrupt caused by the spallation target has been recorded -indeed a convincing evidence for the reliability of this system. The probes inserted into the target and some of its parts will now soon be available to the materials scientists for careful investigation. SINQ as a continuous spallation neutron source was considered to be a 'high risk' project. Furthermore it was often accompanied with the suspicion to represent the 'worst of two worlds' - meaning that this facility would suffer from the disadvantages but not benefit from the advantage of a spallation neutron source - the pulse structure. According to our operational experience these fears are not justified provided the various concerns have been properly taken into consideration during design and construction. This report testifies what can be achieved at a continuous spallation neutron source. We believe that these research activities compare well with those from a beam-tube reactor of medium flux. A list of scientific publications in 2000 is also provided

  1. A review on the relativistic effective field theory with parameterized couplings for nuclear matter and neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, C. A. Zen, E-mail: cesarzen@cesarzen.com [Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, 91501-970, Porto Alegre (Brazil); International Center for Relativistic Astrophysics Network (ICRANet), Piazza della Repubblica 10, 65122 Pescara (Italy)

    2015-12-17

    Nuclear science has developed many excellent theoretical models for many-body systems in the domain of the baryon-meson strong interaction for the nucleus and nuclear matter at low, medium and high densities. However, a full microscopic understanding of nuclear systems in the extreme density domain of compact stars is still lacking. The aim of this contribution is to shed some light on open questions facing the nuclear many-body problem at the very high density domain. Here we focus our attention on the conceptual issue of naturalness and its role in shaping the baryon-meson phase space dynamics in the description of the equation of state (EoS) of nuclear matter and neutrons stars. In particular, in order to stimulate possible new directions of research, we discuss relevant aspects of a recently developed relativistic effective theory for nuclear matter within Quantum Hadrodynamics (QHD) with genuine many-body forces and derivative natural parametric couplings. Among other topics we discuss in this work the connection of this theory with other known effective QHD models of the literature and its potentiality in describing a new physics for dense matter. The model with parameterized couplings exhausts the whole fundamental baryon octet (n, p, Σ{sup −}, Σ{sup 0}, Σ{sup +}, Λ, Ξ{sup −}, Ξ{sup 0}) and simulates n-order corrections to the minimal Yukawa baryon couplings by considering nonlinear self-couplings of meson fields and meson-meson interaction terms coupled to the baryon fields involving scalar-isoscalar (σ, σ∗), vector-isoscalar (ω, Φ), vector-isovector (ϱ) and scalar-isovector (δ) virtual sectors. Following recent experimental results, we consider in our calculations the extreme case where the Σ{sup −} experiences such a strong repulsion that its influence in the nuclear structure of a neutron star is excluded at all. A few examples of calculations of properties of neutron stars are shown and prospects for the future are discussed.

  2. A device for combined neutron-photon processes in condensed matter

    International Nuclear Information System (INIS)

    Stoeckli, A.; Isacson, A.; Koch, M.; Furrer, A.

    1985-01-01

    A device has been developed for performing neutron scattering experiments with simultaneous irradiation by light at low temperatures. The light source is a halogen lamp which yields broad bands of wavelengths between 400 and 1000 nm by using appropriate filters. The light is guided by a series of lenses to the sample, which is mounted in a cooling system. A mechanical chopper may be inserted into the light beam in order to create light pulses with frequencies between 0.05 Hz and 5 Hz, and the neutron counts resulting from the dark and light experiments are separately stored. Our device has been used to study the light-induced dynamical behaviour of photosynthetic chlorophyll systems by neutron spectroscopy. (author)

  3. Neutron propagation in moving matter: the Fizeau experiment with massive particles

    International Nuclear Information System (INIS)

    Klein, A.G.; Opat, G.I.; Cimmino, A.

    1981-01-01

    Using a two-slit neutron interferometer, the authors have mesured the shift of the interference pattern induced by the motion of a quartz rod. The measured shift is found to be in agreement with the quantum mechanical prediction derived from a relativity argument. Some peculiarities of the case of massive particles as compared with the classic Fizeau photon case are discussed

  4. Paul Scherrer Institut Scientific Report 2001. Volume III: Condensed Matter Research with Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, J.; Castellazzi, D.; Shea-Braun, M. (eds.)

    2002-03-01

    The SINQ-facility stopped operation at the end of the year 2001 for the scheduled shut down. By that time the spallation target of the 'Cannelloni'-type (D{sub 2}O-cooled steel pins filled with lead) had received a total charge of more then 10 Ah at an average proton current higher than 1 mA. Thereby nearly 4 mols of neutrons had been released from this target. The two operational years with this target delivered the neutrons for about 300 experiments. During this operational period not one single interrupt caused by the spallation target has been recorded -indeed a convincing evidence for the reliability of this system. The probes inserted into the target and some of its parts will now soon be available to the materials scientists for careful investigation. SINQ as a continuous spallation neutron source was considered to be a 'high risk' project. Furthermore it was often accompanied with the suspicion to represent the 'worst of two worlds' - meaning that this facility would suffer from the disadvantages but not benefit from the advantage of a spallation neutron source - the pulse structure. According to our operational experience these fears are not justified provided the various concerns have been properly taken into consideration during design and construction. This report testifies what can be achieved at a continuous spallation neutron source. We believe that these research activities compare well with those from a beam-tube reactor of medium flux. A list of scientific publications in 2000 is also provided.

  5. Exploring matter through photons and neutrons: from biological molecules to designer materials

    International Nuclear Information System (INIS)

    Chidambaram, R.; Hosur, M.V.; Ramanadham, M.; Godwal, B.K.

    2000-01-01

    Understanding structure-property relationships of naturally occurring materials has been the aim of scientific research for centuries. The discovery of short wavelength x-rays and neutrons in the 20th century provided a means of studying molecular structure. The methodology of x-ray and neutron diffraction has been successfully applied to determine structures of molecules across disciplines of physics, chemistry, biology, biochemistry and medicine. Typical applications in physics include study of phase transformations, elasticity measurements, magnetic structure, surface scattering etc. In chemistry, the applications have ranged from routine structure determinations of reaction intermediates or natural products to refinement of quantum chemical parameters of atomic and molecular charge densities. The science of crystallography has had a profound effect on the disciplines of biology and medicine. A whole new discipline and industry was created when the structure of DNA was discovered through x-ray diffraction

  6. Effect Of Superfluidity And Differential Rotation Of Quark Matter On Magetic Field Evolution in Neutron Star And Black Hole

    Science.gov (United States)

    Aurongzeb, Deeder

    2010-11-01

    Anomalous X-ray pulsars and soft gamma-ray repeaters reveal that existence of very strong magnetic field(> 10e15G) from neutron stars. It has been estimated that at the core the magnitude can be even higher at the center. Apart from dynamo mechanism it has been shown that color locked ferromagnetic phase [ Phys. Rev. D. 72,114003(2005)] can be a possible origin of magnetic field. In this study, we explore electric charge of strange quark matter and its effect on forming chirality in the quark-gluon plasma. We show that electromagnetic current induced by chiral magnetic effect [(Phys. Rev. D. 78.07033(2008)] can induce differential rotation in super fluid quark-gluon plasma giving additional boost to the magnetic field. The internal phase and current has no effect from external magnetic field originating from active galactic nuclei due to superconducting phase formation which screens the fields due to Meissner effect. We show that differential motion can create high radial electric field at the surface making all radiation highly polarized and directional including thermal radiation. As the electric field strength can be even stronger for a collapsing neutron star, the implication of this study to detect radiation from black holes will also be discussed. The work was partly completed at the University of Texas at austin

  7. Constraining the Dense Matter Equation of State with ATHENA-WFI observations of Neutron Stars in Quiescent LMXBs

    Science.gov (United States)

    Guillot, Sebastien; Oezel, F.

    2015-09-01

    The study of neutron star quiescent low-mass X-ray binaries (qLMXBs) will address one of the main science goals of the Athena x-ray observatory. The study of the soft X-ray thermal emission from the neutron star surface in qLMXBs is a crucial tool to place constrains on the dense matter equation of state. I will briefly review this method, its strength and current weaknesses and limitations, as well as the current constraints on the equation of state from qLMXBs. The superior sensitivity of Athena will permit the acquisition of unprecedentedly high signal-to-noise spectra from these sources. It has been demonstrated that a single qLMXB, even with high S/N, will not place useful constraints on the EoS. However, a combination of qLMXBs spectra has shown promises of obtaining tight constraints on the equation of state. I will discuss the expected prospects for observations of qLMXBs inside globular clusters -- those that Athena will be able to resolve. I will also present the constraints on the equation of state that Athena will be able to obtain from these qLMXBs and from a population of qLMXBs in the field of the Galaxy, with distance measurements provided by Gaia.

  8. SECULAR EVOLUTION OF COMPACT BINARIES NEAR MASSIVE BLACK HOLES: GRAVITATIONAL WAVE SOURCES AND OTHER EXOTICA

    International Nuclear Information System (INIS)

    Antonini, Fabio; Perets, Hagai B.

    2012-01-01

    The environment near supermassive black holes (SMBHs) in galactic nuclei contains a large number of stars and compact objects. A fraction of these are likely to be members of binaries. Here we discuss the binary population of stellar black holes and neutron stars near SMBHs and focus on the secular evolution of such binaries, due to the perturbation by the SMBH. Binaries with highly inclined orbits with respect to their orbit around the SMBH are strongly affected by secular Kozai processes, which periodically change their eccentricities and inclinations (Kozai cycles). During periapsis approach, at the highest eccentricities during the Kozai cycles, gravitational wave (GW) emission becomes highly efficient. Some binaries in this environment can inspiral and coalesce at timescales much shorter than a Hubble time and much shorter than similar binaries that do not reside near an SMBH. The close environment of SMBHs could therefore serve as a catalyst for the inspiral and coalescence of binaries and strongly affect their orbital properties. Such compact binaries would be detectable as GW sources by the next generation of GW detectors (e.g., advanced-LIGO). Our analysis shows that ∼0.5% of such nuclear merging binaries will enter the LIGO observational window while on orbits that are still very eccentric (e ∼> 0.5). The efficient GW analysis for such systems would therefore require the use of eccentric templates. We also find that binaries very close to the SMBH could evolve through a complex dynamical (non-secular) evolution, leading to emission of several GW pulses during only a few years (though these are likely to be rare). Finally, we note that the formation of close stellar binaries, X-ray binaries, and their merger products could be induced by similar secular processes, combined with tidal friction rather than GW emission as in the case of compact object binaries.

  9. Vortex matter beyond SANS. Neutron studies of vortex structures covering a length scale of 0.01 ti 10 μm

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, Tommy

    2017-01-09

    This thesis is concerned with different generic types of vortex matter arising in the intermediate state of the type-I superconductor lead, the intermediate mixed state of the type-II superconductor niobium, and the helimagnetic phase of the compound manganese silicide. It is demonstrated and explained how a combination of i) the radiographic techniques neutron grating interferometry and neutron diffractive imaging with ii) scattering methods such as small-angle-neutron scattering and ultra-small-angle neutron scattering can provide novel insight into the bulk behavior of these vortex systems. By means of the used scattering methods, detailed information on the morphology of the vortex phases covering a length scale of 0.01 to 10 μm are obtained, while the radiographic approaches additionally map the spatial distribution of vortices within the sample. In particular, this thesis focuses on the strong influences of demagnetization, geometric barriers and pinning on the vortex configuration.

  10. Vortex matter beyond SANS. Neutron studies of vortex structures covering a length scale of 0.01 ti 10 μm

    International Nuclear Information System (INIS)

    Reimann, Tommy

    2017-01-01

    This thesis is concerned with different generic types of vortex matter arising in the intermediate state of the type-I superconductor lead, the intermediate mixed state of the type-II superconductor niobium, and the helimagnetic phase of the compound manganese silicide. It is demonstrated and explained how a combination of i) the radiographic techniques neutron grating interferometry and neutron diffractive imaging with ii) scattering methods such as small-angle-neutron scattering and ultra-small-angle neutron scattering can provide novel insight into the bulk behavior of these vortex systems. By means of the used scattering methods, detailed information on the morphology of the vortex phases covering a length scale of 0.01 to 10 μm are obtained, while the radiographic approaches additionally map the spatial distribution of vortices within the sample. In particular, this thesis focuses on the strong influences of demagnetization, geometric barriers and pinning on the vortex configuration.

  11. Numerical generalized vibration density of states evaluation for inelastic neutron scattering in solid matter

    CERN Document Server

    Kazmianec, V; Aranghel, D

    2002-01-01

    A computational method for improved evaluation of the generalized vibration density of states (GVDS) is proposed. It is based on Fast Fourier Transform (FPT) technique and gives the possibility for more precise analyses of the neutron double differential scattering cross section. The method was applied to zirconium hydride investigation. The results were presented for ZrH sub 1 sub . sub 6 U sub 0 sub . sub 3 sub 2 sample at various temperatures on time-of-flight (TOF) Spectrometry at IBR-2 reactor of JINR-Dubna and were compared to GVDS values obtained by traditional single-phonon approximation method

  12. Neutron and X-ray Scattering Study of Structure and Dynamics of Condensed Matters

    Science.gov (United States)

    Fujii, Yasuhiko

    In this article, I have reviewed a series of research on a various phase transitions such as (1) structural phase transitions of perovskite compounds driven by soft phonons, (2) pressure-induced molecular dissociation and metallization observed in solid halogens, and (3) the “Devil's Flower” type phase diagram observed in two compounds with frustrating interactions. Also commented is on the so-called “Small Science at Large Facility” typically symbolized by neutron and synchrotron radiation experiments like the present research.

  13. Investigation on trace elements in crude oil and organic matter extracted from rocks with instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Ding Zuguo; Chai Zhifang

    1990-01-01

    Solvent extraction, column chromatography and instrumental neutron activation analysis(INAA) have been used to investigate the trace elements in crude oil, organic matter extracted from rocks and their related fractions. With these methods, about 70 crude oil samples from eight different oil fields in China and 6 extracted asphaltene samples of the lower paleozoic from the upper Yangtze region have been analyzed, and about 40 elements of interest have been determined. Those elements include Al, As, Au, Ba, Br, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, Ir, Mg, Mn, Mo, Na, Ni, Rb, Re, S, Sb, Sc, Se, Sr, Th, Zn, V and parts of REE. The experimental results show that the method possesses several advantages, i.e. non-destructive, multi-elements, sensitive, precise and accurate. Without ashing samples, the loss of volatile elements such as Cl, S, Se and Sb are avoided. The column chromatography makes it possible to study the distributions of trace elements in different fractions of crude oil and organic matter extracted. Meanwhile, the characters of trace elements in them have also been discussed

  14. Hunting for neutral, long-lived exotica at the LHC using a missing transverse energy signature

    International Nuclear Information System (INIS)

    Belyaev, Alexander; Moretti, Stefano; Nickel, Kilian; Thomas, Marc C.; Tomalin, Ian

    2016-01-01

    Searches at the Large Hadron Collider (LHC) for neutral, long-lived particles have historically relied on the detection of displaced particles produced by their decay within the detector volume. In this paper we study the potential of the complementary signature comprising of the missing transverse energy (E T miss ) signal, traditionally used to look for dark matter, e.g., the lightest supersymmetric particle (LSP), to extend the LHC coverage to models with long-lived (LL) particles when they decay outside the detector. Using CMS and ATLAS analyses at the 8 TeV LHC, we set an upper limit at the 95% confidence level (CL) on the production cross sections for two specific scenarios: (i) a model with a heavy non-standard model Higgs boson decaying to a LL scalar and (ii) an R-parity violating (RPV) SUSY model with a LL neutralino. We show that this method can significantly extend the LHC sensitivity to neutral, LL particles with arbitrary large lifetimes and that the limits obtained from a E T miss signal are comparable to those from displaced particle searches for decay distances above a few meters. Results obtained in this study do not depend on the specific decay channel of the LL particle and therefore are model-independent in this sense. We provide limits for the whole two-dimensional plane in terms of the mass of the LL particle and the mass of the mediator up to masses of 2 TeV including particular benchmarks studied in the original experimental papers. We have made these limits available in the form of a grid which can be used for the interpretation of various other new physics models.

  15. Computational methods for the nuclear and neutron matter problem. Progress report

    International Nuclear Information System (INIS)

    Kalos, M.H.; Carlson, J.; Panoff, R.; Schmidt, K.

    1985-10-01

    A new method is presented for treating fermion systems by Monte Carlo methods. This method is based on the concept of a ''mirror potential,'' which is a many-body potential that forces the Monte Carlo iteration to have a stable anti-symmetric component. The potential may be determined from the wave function and, within the framework of Green's Function Monte Carlo (GFMC), from the random walk whose density converges to the wave function. Further work has been given to the variational study of light nuclei. In particular, microscopic calculations of alpha-neutron scattering were performed. Techniques were also developed for performing variational calculations of heavier nuclei interacting with realistic interactions. A series of calculations on liquid 3 He at its experimental equilibrium density has also been done. 42 refs

  16. Neutron radiative capture reactions on nuclei of relevance to 0νββ, dark matter and neutrino/antineutrino searches

    Science.gov (United States)

    Tornow, W.; Bhike, Megha

    2015-05-01

    A program is underway at the Triangle Universities Nuclear Laboratory (TUNL) to measure the neutron capture cross section in the 0.5 to 15 MeV energy range on nuclei whose radioactive daughters could potentially create backgrounds in searches for rare events. Here, we refer to neutrino-less double-beta decay and dark-matter searches, and to detectors built for neutrino and/or antineutrino studies. Neutron capture cross-section data obtained by using the activation method are reported for 40Ar, 74,76Ge, 128,130Te and 136Xe and compared to model calculations and evaluations.

  17. Neutron radiative capture reactions on nuclei of relevance to 0νββ, dark matter and neutrino/antineutrino searches

    Directory of Open Access Journals (Sweden)

    Tornow W.

    2015-01-01

    Full Text Available A program is underway at the Triangle Universities Nuclear Laboratory (TUNL to measure the neutron capture cross section in the 0.5 to 15 MeV energy range on nuclei whose radioactive daughters could potentially create backgrounds in searches for rare events. Here, we refer to neutrino-less double-beta decay and dark-matter searches, and to detectors built for neutrino and/or antineutrino studies. Neutron capture cross-section data obtained by using the activation method are reported for 40Ar, 74,76Ge, 128,130Te and 136Xe and compared to model calculations and evaluations.

  18. Neutron radiative capture reactions on nuclei of relevance to 0νββ, dark matter and neutrino/antineutrino searches

    OpenAIRE

    Tornow W.; Bhike Megha

    2015-01-01

    A program is underway at the Triangle Universities Nuclear Laboratory (TUNL) to measure the neutron capture cross section in the 0.5 to 15 MeV energy range on nuclei whose radioactive daughters could potentially create backgrounds in searches for rare events. Here, we refer to neutrino-less double-beta decay and dark-matter searches, and to detectors built for neutrino and/or antineutrino studies. Neutron capture cross-section data obtained by using the activation method are reported for 40Ar...

  19. Determination of trace elements in total particulate matter of cigarette smoke by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Mishra, U.C.; Shaikh, G.N.

    1985-01-01

    Cigarette smoke contains many trace elements hazardous for human body. Tobacco samples were analyzed for their trace element contents and the results were reported earlier. This paper presents results on the trace element content analyzed in cigarette smoke using an automatic smoking machine developed in laboratory to simulate actual smoking pattern. The trace element levels in the total particulate matter samples of the cigarette smoke collected on filter papers were measured and compared with those of cigarette smoke condensate reported in the literature. Both methods of collection give comparable results. (author)

  20. Neutron transport

    International Nuclear Information System (INIS)

    Berthoud, Georges; Ducros, Gerard; Feron, Damien; Guerin, Yannick; Latge, Christian; Limoge, Yves; Santarini, Gerard; Seiler, Jean-Marie; Vernaz, Etienne; Coste-Delclaux, Mireille; M'Backe Diop, Cheikh; Nicolas, Anne; Andrieux, Catherine; Archier, Pascal; Baudron, Anne-Marie; Bernard, David; Biaise, Patrick; Blanc-Tranchant, Patrick; Bonin, Bernard; Bouland, Olivier; Bourganel, Stephane; Calvin, Christophe; Chiron, Maurice; Damian, Frederic; Dumonteil, Eric; Fausser, Clement; Fougeras, Philippe; Gabriel, Franck; Gagnier, Emmanuel; Gallo, Daniele; Hudelot, Jean-Pascal; Hugot, Francois-Xavier; Dat Huynh, Tan; Jouanne, Cedric; Lautard, Jean-Jacques; Laye, Frederic; Lee, Yi-Kang; Lenain, Richard; Leray, Sylvie; Litaize, Olivier; Magnaud, Christine; Malvagi, Fausto; Mijuin, Dominique; Mounier, Claude; Naury, Sylvie; Nicolas, Anne; Noguere, Gilles; Palau, Jean-Marc; Le Pallec, Jean-Charles; Peneliau, Yannick; Petit, Odile; Poinot-Salanon, Christine; Raepsaet, Xavier; Reuss, Paul; Richebois, Edwige; Roque, Benedicte; Royer, Eric; Saint-Jean, Cyrille de; Santamarina, Alain; Serot, Olivier; Soldevila, Michel; Tommasi, Jean; Trama, Jean-Christophe; Tsilanizara, Aime; Behar, Christophe; Provitina, Olivier; Lecomte, Michael; Forestier, Alain; Bender, Alexandra; Parisot, Jean-Francois; Finot, Pierre

    2013-10-01

    This bibliographical note presents a reference book which addresses the study of neutron transport in matter, the study of conditions for a chain reaction and the study of modifications of matter composition due to nuclear reactions. This book presents the main nuclear data, their measurement, assessment and processing, and the spallation. It proposes an overview of methods applied for the study of neutron transport: basic equations and their derived forms, deterministic methods and Monte Carlo method of resolution of the Boltzmann equation, methods of resolution of generalized Bateman equations, methods of time resolution of space kinetics coupled equations. It presents the main calculation codes, discusses the qualification and experimental aspects, and gives an overview of neutron transport applications: neutron transport calculation of reactors, neutron transport coupled with other disciplines, physics of fuel cycle, criticality

  1. High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter; La spectroscopie de neutrons a haute resolution-un outil pour l'etude de la dynamique des polymeres et de la matiere molle

    Energy Technology Data Exchange (ETDEWEB)

    Monkenbusch, M.; Richter, D. [Institut fur Festkorperforschung (IFF), Forschungszentrum Julich, Julich (Germany)

    2007-09-15

    Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

  2. Report on the meeting of the working groups on neutron scattering applied to studying condensed matter, and neutron scattering and complementary methods applied in chemistry and biology

    International Nuclear Information System (INIS)

    1985-06-01

    The present volume consists of 55 lectures. The subjects are: 1) Elastic neutron diffraction, 2) Lattice dynamics, 3) Diffusion, 4) Polymers, 5) Biology, 6) Methods and tools, 7) Magnetism. For distinct papers see hints under relevant topics. (BHO)

  3. Design of a versatile detector for the detection of charged particles, neutrons and gamma rays. Neutron interaction with the matter; Diseno de un detector versatil para la deteccion de particulas cargadas, neutrones y rayos gamma. Interaccion neutronica con la materia

    Energy Technology Data Exchange (ETDEWEB)

    Perez P, J J [Comision Nacional de Seguridad Nuclear y Salvaguardias, Mexico, D.F. (Mexico)

    1991-07-01

    The Fostron detector detects charged particles, neutrons and gamma rays with a reasonable discrimination power. Because the typical detectors for neutrons present a great uncertainty in the detection, this work was focused mainly to the neutron detection in presence of gamma radiation. Also there are mentioned the advantages and disadvantages of the Fostron detector.

  4. Concluding Remarks: Connecting Relativistic Heavy Ion Collisions and Neutron Star Mergers by the Equation of State of Dense Hadron- and Quark Matter as signalled by Gravitational Waves

    Science.gov (United States)

    Hanauske, Matthias; Steinheimer, Jan; Bovard, Luke; Mukherjee, Ayon; Schramm, Stefan; Takami, Kentaro; Papenfort, Jens; Wechselberger, Natascha; Rezzolla, Luciano; Stöcker, Horst

    2017-07-01

    The underlying open questions in the fields of general relativistic astrophysics and elementary particle and nuclear physics are strongly connected and their results are interdependent. Although the physical systems are quite different, the 4D-simulation of a merger of a binary system of two neutron stars and the properties of the hot and dense matter created in high energy heavy ion collisions, strongly depend on the equation of state of fundamental elementary matter. Neutron star mergers represent optimal astrophysical laboratories to investigate the QCD phase structure using a spectrogram of the post-merger phase of the emitted gravitational waves. These studies can be supplemented by observations from heavy ion collisions to possibly reach a conclusive picture on the QCD phase structure at high density and temperature. As gravitational waves (GWs) emitted from merging neutron star binaries are on the verge of their first detection, it is important to understand the main characteristics of the underlying merging system in order to predict the expected GW signal. Based on numerical-relativity simulations of merging neutron star binaries, the emitted GW and the interior structure of the generated hypermassive neutron stars (HMNS) have been analyzed in detail. This article will focus on the internal and rotational HMNS properties and their connection with the emitted GW signal. Especially, the appearance of the hadon-quark phase transition in the interior region of the HMNS and its conjunction with the spectral properties of the emitted GW will be addressed and confronted with the simulation results of high energy heavy ion collisions.

  5. Dark Matter

    Indian Academy of Sciences (India)

    As if this was not enough, it turns out that if our knowledge of ... are thought to contain dark matter, although the evidences from them are the .... protons, electrons, neutrons ... ratio of protons to neutrons was close to unity then as they were in ...

  6. VESUVIO: a novel instrument for performing spectroscopic studies in condensed matter with eV neutrons at the ISIS facility

    Science.gov (United States)

    Senesi, R.; Andreani, C.; Bowden, Z.; Colognesi, D.; Degiorgi, E.; Fielding, A. L.; Mayers, J.; Nardone, M.; Norris, J.; Praitano, M.; Rhodes, N. J.; Stirling, W. G.; Tomkinson, J.; Uden, C.

    2000-03-01

    The VESUVIO project aims to provide unique prototype instrumentation at the ISIS-pulsed neutron source and to establish a routine experimental and theoretical program in neutron scattering spectroscopy at eV energies. This instrumentation will be specifically designed for high momentum, (20 Å-11 eV) inelastic neutron scattering studies of microscopic dynamical processes in materials and will represent a unique facility for EU researchers. It will allow to derive single-particle kinetic energies and single-particle momentum distributions, n(p), providing additional and/or complementary information to other neutron inelastic spectroscopic techniques.

  7. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

    The thermal neutron absorption coefficient is essentially different from the X-ray absorption coefficient. Each substance has a characteristic absorption coefficient regardless of its density. Neutron deams have the following features: (1) neutrons are not transmitted efficiently by low molecular weight substances, (2) they are transmitted efficiently by heavy metals, and (3) the transmittance differs among isotopes. Thus, neutron beams are suitable for cheking for foreign matters in heavy metals and testing of composites consisting of both heavy and light materials. A neutron source generates fast neutrons, which should be converted into thermal neutrons by reducing their energy. Major neutron souces include nuclear reactors, radioisotopes and particle accelerators. Photographic films and television systems are mainly used to observe neutron transmission images. Computers are employed for image processing, computerized tomography and three-dimensional analysis. The major applications of neutron radiography include inspection of neclear fuel; evaluation of material for airplane; observation of fuel in the engine and oil in the hydraulic systems in airplanes; testing of composite materials; etc. (Nogami, K.)

  8. Requirements of data acquisition and analysis for condensed matter studies at the weapons neutron research/proton storage ring facility

    International Nuclear Information System (INIS)

    Johnson, M.W.; Goldstone, J.A.; Taylor, A.D.

    1982-11-01

    With the completion of the proton storage ring (PSR) in 1985, the subsquent increase in neutron flux, and the continuing improvement in neutron scattering instruments, a significant improvement in data acquisition and data analysis capabilities will be required. A brief account of the neutron source is given together with the associated neutron scattering instruments. Based on current technology and operating instruments, a projection for 1985 to 1990 of the neutron scattering instruments and their main parameters are given. From the expected data rates and the projected instruments, the size of data storage is estimated and the user requirements are developed. General requirements are outlined with specific requirements in user hardware and software stated. A project time scale to complete the data acquisition and analysis system by 1985 is given

  9. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    of desired information. In the course, an introduction into the method and an overview on selected instruments at large scale facilities will be presented. Examples will be given that illustrate the potential of the method, mostly based on organic films. Results from the investigation of layered films......Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... films or films with magnetic properties. The reason is the peculiar property of neutron light since the mass of a neutron is close to the one of a proton, and since it bears a magnetic moment. The optical properties of matter, when interacting with neutrons, are described by a refractive index...

  10. [A new taxonomic system of the genus Murraya (Rutaceae) based on integration of morphology-based taxonomy and chemotaxonomy; and a philological survey on M. exotica in view of the relationship between Okinawa and China].

    Science.gov (United States)

    Kinoshita, Takeshi

    2014-01-01

    This review concerns the taxonomic status of the genus Murraya in tribe Clausenae, subfamily Aurantioideae, family Rutaceae, and presents a new system integrating both morphology-based taxonomy and chemotaxonomy. This genus has been morphologically divided into the sects Murraya and Bergera. This dichotomy is justified by the noticeable difference of secondary metabolites with 3-prenylindoles in Murraya and carbazoles in Bergera. As for other metabolites of genus Murraya, coumarins are found in both sects, but differ clearly in types; 8-prenylcoumarins occur throughout the sect Murraya whereas geranylated furocoumarins are known from some species of the sect Bergera. As far as chemical properties are concerned, sect Bergera is much closer to genus Clausena than sect Murraya, suggesting the dichotomy of genus Murraya to be generic rather than sectional. 8-Prenylcoumarins characterizing sect Murraya play a decisive role in the distinction of M. exotica from M. paniculata that occurs most widely in subtropical and tropical Asia and is well known for morphologic as well as chemical diversity. Though the morphological difference between the two species is slight only in leaves and leaflets, the distinction is well substantiated by the following chemical feature: 7-OMe-8-prenylcoumarins occur in M. exotica whereas 5,7-di-OMe-8-prenylcoumarins in M. paniculata. Sect Murraya has a very close relation to genus Merrillia that is chemically characterized by similar types of 8-prenylcoumarins, and is also related to a certain extent to genus Micromelum. M. exotica is philologically surveyed in view of the delicate relationships between Okinawa, the only habitat of this plant in Japan, and China in order to clarify its historical background.

  11. First 5 tower WIMP-search results from the Cryogenic Dark Matter Search with improved understanding of neutron backgrounds and benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Hennings-Yeomans, Raul [Case Western Reserve Univ., Cleveland, OH (United States)

    2009-02-01

    Non-baryonic dark matter makes one quarter of the energy density of the Universe and is concentrated in the halos of galaxies, including the Milky Way. The Weakly Interacting Massive Particle (WIMP) is a dark matter candidate with a scattering cross section with an atomic nucleus of the order of the weak interaction and a mass comparable to that of an atomic nucleus. The Cryogenic Dark Matter Search (CDMS-II) experiment, using Ge and Si cryogenic particle detectors at the Soudan Underground Laboratory, aims to directly detect nuclear recoils from WIMP interactions. This thesis presents the first 5 tower WIMP-search results from CDMS-II, an estimate of the cosmogenic neutron backgrounds expected at the Soudan Underground Laboratory, and a proposal for a new measurement of high-energy neutrons underground to benchmark the Monte Carlo simulations. Based on the non-observation of WIMPs and using standard assumptions about the galactic halo [68], the 90% C.L. upper limit of the spin-independent WIMPnucleon cross section for the first 5 tower run is 6.6 × 10-44cm2 for a 60 GeV/c2 WIMP mass. A combined limit using all the data taken at Soudan results in an upper limit of 4.6×10-44cm2 at 90% C.L.for a 60 GeV/c2 WIMP mass. This new limit corresponds to a factor of ~3 improvement over any previous CDMS-II limit and a factor of ~2 above 60 GeV/c 2 better than any other WIMP search to date. This thesis presents an estimation, based on Monte Carlo simulations, of the nuclear recoils produced by cosmic-ray muons and their secondaries (at the Soudan site) for a 5 tower Ge and Si configuration as well as for a 7 supertower array. The results of the Monte Carlo are that CDMS-II should expect 0.06 ± 0.02+0.18 -0.02 /kgyear unvetoed single nuclear recoils in Ge for the 5 tower configuration, and 0.05 ± 0.01+0.15 -0.02 /kg-year for the 7 supertower configuration. The systematic error is based on the available

  12. Production of neutrons up to 18 MeV in high-intensity, short-pulse laser matter interactions

    Energy Technology Data Exchange (ETDEWEB)

    Higginson, D. P. [Mechanical and Aerospace Engineering, University of California-San Diego, La Jolla, California 92093 (United States); Lawrence Livermore National Laboratory, Livermore, California 94440 (United States); McNaney, J. M.; Swift, D. C.; Mackinnon, A. J.; Patel, P. K. [Lawrence Livermore National Laboratory, Livermore, California 94440 (United States); Petrov, G. M.; Davis, J. [Naval Research Laboratory, Plasma Physics Division, Washington, DC 20375 (United States); Frenje, J. A. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Jarrott, L. C.; Tynan, G.; Beg, F. N. [Mechanical and Aerospace Engineering, University of California-San Diego, La Jolla, California 92093 (United States); Kodama, R.; Nakamura, H. [Institute of Laser Engineering, Osaka University, 2-5 Yamada-oka, Suita, Osaka 454-0871 (Japan); Lancaster, K. L. [STFC Rutherford Appleton Laboratory, Chilton, Oxon OX11OQX (United Kingdom)

    2011-10-15

    The generation of high-energy neutrons using laser-accelerated ions is demonstrated experimentally using the Titan laser with 360 J of laser energy in a 9 ps pulse. In this technique, a short-pulse, high-energy laser accelerates deuterons from a CD{sub 2} foil. These are incident on a LiF foil and subsequently create high energy neutrons through the {sup 7}Li(d,xn) nuclear reaction (Q = 15 MeV). Radiochromic film and a Thomson parabola ion-spectrometer were used to diagnose the laser accelerated deuterons and protons. Conversion efficiency into protons was 0.5%, an order of magnitude greater than into deuterons. Maximum neutron energy was shown to be angularly dependent with up to 18 MeV neutrons observed in the forward direction using neutron time-of-flight spectrometry. Absolutely calibrated CR-39 detected spectrally integrated neutron fluence of up to 8 x 10{sup 8} n sr{sup -1} in the forward direction.

  13. Preparative isolation and purification of hainanmurpanin, meranzin, and phebalosin from leaves of Murraya exotica L. using supercritical fluid extraction combined with consecutive high-speed countercurrent chromatography.

    Science.gov (United States)

    Yan, Rongwei; Shen, Jie; Liu, Xiaojing; Zou, Yong; Xu, Xinjun

    2018-05-01

    The objective of this study was to develop a consecutive preparation method for the isolation and purification of hainanmurpanin, meranzin, and phebalosin from leaves of Murraya exotica L. The process involved supercritical fluid extraction with CO 2 , solvent extraction, and two-step high-speed countercurrent chromatography. Pressure, temperature, and the volume of entrainer were optimized as 27 MPa, 52°C, and 60 mL by response surface methodology in supercritical fluid extraction with CO 2 , and the yield of the crude extracts was 7.91 g from 100 g of leaves. Subsequently, 80% methanol/water was used to extract and condense the three compounds from the crude extracts, and 4.23 g of methanol/water extracts was obtained. Then, a two-step high-speed countercurrent chromatography procedure was developed for the isolation of the three target compounds from methanol/water extracts, including conventional high-speed countercurrent chromatography for further enrichment and consecutive high-speed countercurrent chromatography for purification. The yield of concentrates from high-speed countercurrent chromatography was 2.50 g from 4.23 g of methanol/water extracts. Finally, the consecutive high-speed countercurrent chromatography produced 103.2 mg of hainanmurpanin, 244.7 mg of meranzin, and 255.4 mg of phebalosin with purities up to 97.66, 99.36, and 98.64%, respectively, from 900 mg of high-speed countercurrent chromatography concentrates in one run of three consecutive sample loadings without exchanging a solvent system. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Determination of elemental concentrations in airborne particulate matter in the City of Santiago de Chile, through neutron activation analysis using epithermal neutrons and Compton suppression system

    International Nuclear Information System (INIS)

    Rojas S, Ximena

    1995-01-01

    In order to optimize the Neutron-Activation Analysis (NAA) technique currently carried out in our country, the present work was carried out in the United States where irradiations with epithermal neutrons and a Compton suppression system were used, which allowed the characterization of aerosols of the city of Santiago de Chile. With this purpose, 54 filters of polycarbonate membranes were analysed with aerosols collected in an area of the capital during Spring 1993 and Winter of 1994. As a result, an improvement in the detection limits was observed, specially in elements such as Ni and Zn, which are not easily detectable through NAA. The application of both systems also permits the usage of this technique in geological and biological samples, where the presence of Na, Al and Cl obstruct the determination of some elements. The determined elements in both fractions were Mn, V, Cu, As, Sb, Co, Br, Cl, Ni, Zn, Ca, Al, Na and Fe. (author). 8 refs., 7 figs., 9 tabs

  15. Mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter within the relativistic impulse approximation

    International Nuclear Information System (INIS)

    Jiang Weizhou; Li Baoan; Chen Liewen

    2007-01-01

    The mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter are investigated using the nucleon optical potential obtained within the relativistic impulse approximation with the empirical nucleon-nucleon scattering amplitudes and the nuclear densities obtained in the relativistic mean-field model. It is found that the isospin-splitting of nucleon mean free paths, sensitive to the imaginary part of the symmetry potential, changes its sign at certain high kinetic energy. The in-medium nucleon-nucleon cross sections are analytically and numerically demonstrated to be essentially independent of the isospin asymmetry of the medium and increase linearly with density in the high-energy region where the relativistic impulse approximation is applicable

  16. Neutrons as a probe

    International Nuclear Information System (INIS)

    Iizumi, Masashi

    1993-01-01

    As an introduction to the symposium a brief overview will be given about the features of neutrons as a probe. First it will be pointed out that the utilization of neutrons as a probe for investigating the structural and dynamical properties of condensed matters is a benign gift eventuated from the release of atomic energy initiated by Enrico Fermi exactly half century ago. Features of neutrons as a probe are discussed in accordance with the four basic physical properties of neutrons as an elementary particle; (1) no electric charge (the interaction with matter is nuclear), (2) the mass of neutron is 1 amu, (3) spin is 1/2 and (4) neutrons have magnetic dipole moment. Overview will be given on the uniqueness of neutrons as a probe and on the variety in the way they are used in the wide research area from the pure science to the industrial applications. (author)

  17. Introduction to neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Lattimer, James M. [Dept. of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2015-02-24

    Neutron stars contain the densest form of matter in the present universe. General relativity and causality set important constraints to their compactness. In addition, analytic GR solutions are useful in understanding the relationships that exist among the maximum mass, radii, moments of inertia, and tidal Love numbers of neutron stars, all of which are accessible to observation. Some of these relations are independent of the underlying dense matter equation of state, while others are very sensitive to the equation of state. Recent observations of neutron stars from pulsar timing, quiescent X-ray emission from binaries, and Type I X-ray bursts can set important constraints on the structure of neutron stars and the underlying equation of state. In addition, measurements of thermal radiation from neutron stars has uncovered the possible existence of neutron and proton superfluidity/superconductivity in the core of a neutron star, as well as offering powerful evidence that typical neutron stars have significant crusts. These observations impose constraints on the existence of strange quark matter stars, and limit the possibility that abundant deconfined quark matter or hyperons exist in the cores of neutron stars.

  18. Principles of neutron reflection

    International Nuclear Information System (INIS)

    Felcher, G.P.

    1988-08-01

    Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs

  19. Workshop on Probing Frontiers in Matter with Neutron Scattering, Wrap-up Session Chaired by John C. Browne on December 14, 1997, at Fuller Lodge, Los Alamos, New Mexico

    International Nuclear Information System (INIS)

    Mezei, F.; Thompson, J.

    1998-01-01

    The Workshop on Probing Frontiers in Matter with Neutron Scattering consisted of a series of lectures and discussions about recent highlights in neutron scattering. In this report, we present the transcript of the concluding discussion session (wrap-up session) chaired by John C. Browne, Director of Los Alamos National Laboratory. The workshop had covered a spectrum of topics ranging from high T c superconductivity to polymer science, from glasses to molecular biology, a broad review aimed at identifying trends and future needs in condensed matter research. The focus of the wrap-up session was to summarize the workshop participants' views on developments to come. Most of the highlights presented during the workshop were the result of experiments performed at the leading reactor-based neutron scattering facilities. However, recent advances with very high power accelerators open up opportunities to develop new approaches to spallation technique that could decisively advance neutron scattering research in areas for which reactor sources are today by far the best choice. The powerful combination of neutron scattering and increasingly accurate computer modeling emerged as another area of opportunity for research in the coming decades

  20. Workshop on Probing Frontiers in Matter with Neutron Scattering, Wrap-up Session Chaired by John C. Browne on December 14, 1997, at Fuller Lodge, Los Alamos, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mezei, F.; Thompson, J.

    1998-12-01

    The Workshop on Probing Frontiers in Matter with Neutron Scattering consisted of a series of lectures and discussions about recent highlights in neutron scattering. In this report, we present the transcript of the concluding discussion session (wrap-up session) chaired by John C. Browne, Director of Los Alamos National Laboratory. The workshop had covered a spectrum of topics ranging from high T{sub c} superconductivity to polymer science, from glasses to molecular biology, a broad review aimed at identifying trends and future needs in condensed matter research. The focus of the wrap-up session was to summarize the workshop participants' views on developments to come. Most of the highlights presented during the workshop were the result of experiments performed at the leading reactor-based neutron scattering facilities. However, recent advances with very high power accelerators open up opportunities to develop new approaches to spallation technique that could decisively advance neutron scattering research in areas for which reactor sources are today by far the best choice. The powerful combination of neutron scattering and increasingly accurate computer modeling emerged as another area of opportunity for research in the coming decades.

  1. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  2. Instrumental neutron activation analysis as a tool for assessing the solubility of soil mineral matter in strong acid

    International Nuclear Information System (INIS)

    Steinnes, E.; Naeumann, R.

    2004-01-01

    Fifty samples of natural surface soils with high but variable organic matter content were analyzed for 13 elements (Na, Al, K, Sc, V, Cr, Mn, Fe, Co, Zn, Sr, Ba, La) by INAA. The same samples were analyzed for the 'total-recoverable' fraction of these elements by ICP-OES after decomposition with 7M HNO 3 , and the results are compared. The data are discussed separately for two groups of samples with organic matter contents of respectively >80% and Mn (77)>La (60)>Fe = Zn (53)>V (33)>Cr (29)>Sc (25)>Al = Ba (17)>Sr (13)>K (5)>Na (2). The results are in good agreement with corresponding literature data for mineral soils in the case of Al, K, Sc, V, Cr, Fe, and La. In the case of Na, Mn, Co, Zn, Sr, and Ba the present surface soils showed significantly higher 'total-recoverable' fractions than the previously studied subsoils. Possible reasons for these differences are discussed. INAA remains a convenient reference technique for determination of total concentrations with the rapidly increasing use of strong mineral acids in environmental studies of elements. (author)

  3. Stars of strange matter

    International Nuclear Information System (INIS)

    Bethe, H.A.; Brown, G.E.; Cooperstein, J.

    1987-01-01

    We investigate suggestions that quark matter with strangeness per baryon of order unity may be stable. We model this matter at nuclear matter densities as a gas of close packed Λ-particles. From the known mass of the Λ-particle we obtain an estimate of the energy and chemical potential of strange matter at nuclear densities. These are sufficiently high to preclude any phase transition from neutron matter to strange matter in the region near nucleon matter density. Including effects from gluon exchange phenomenologically, we investigate higher densities, consistently making approximations which underestimate the density of transition. In this way we find a transition density ρ tr > or approx.7ρ 0 , where ρ 0 is nuclear matter density. This is not far from the maximum density in the center of the most massive neutron stars that can be constructed. Since we have underestimated ρ tr and still find it to be ∝7ρ 0 , we do not believe that the transition from neutron to quark matter is likely in neutron stars. Moreover, measured masses of observed neutron stars are ≅1.4 M sun , where M sun is the solar mass. For such masses, the central (maximum) density is ρ c 0 . Transition to quark matter is certainly excluded for these densities. (orig.)

  4. High-pressure cells for study of condensed matter by diffraction and inelastic neutron scattering at low temperatures and in strong magnetic fields

    Science.gov (United States)

    Sadykov, R. A.; Strassle, Th; Podlesnyak, A.; Keller, L.; Fak, B.; Mesot, J.

    2017-12-01

    We have developed and implemented series of new original clamp high-pressure cells for neutron diffraction and inelastic neutron scattering at low temperatures. The cells design allows one to place them in the standard cryostats or cryomagnets used on neutron sources. Some results obtained for ZnCr2Se4 are demonstrated as an example.

  5. Neutron beams. Tracks analysis, imaging and medicine

    International Nuclear Information System (INIS)

    Pepy, G.

    2006-01-01

    Thermal neutron beams can supply informations about the arrangement of atoms and molecules and about their movement inside the matter. This article treats of the preparation of thermal neutron beams and of the applications that use their penetration and matter activation properties: 1 - thermal neutrons production; 2 - basic properties of thermal neutrons: neutrons scattering, absorbing materials, activating materials, transparent materials, preparation of a neutron beam; 3 - tracks measurement by activation: activation method, measurement of marine pollution by heavy elements, historical evolution of glass composition; 4 - neutron radiography: neutronography, neutronoscopy: viscosity measurement; 5 - cancer treatment. (J.S.)

  6. The search for QCD exotica

    International Nuclear Information System (INIS)

    Dzierba, A.R.

    1995-01-01

    One of the open questions in non-perturbative QCD has to do with the existence of meson states predicted by the theory other than qq states. These include four-quark states (q 2 q 2 or molecules like KK), states of pure glue (glueballs: gg or ggg) and mixed or hybrid states (qqg). The prima facie candidate for a non-qq state would be one possessing exotic quantum numbers, J PC , not consistent with a qq combination. Examples include J PC =0 +- , 0-- , -+ ,hor-ellipsis Remarkably, states with exotic quantum numbers have not been found despite intensive searches. The case for a possible sighting of an exotic J Jc = 1 -+ state decaying into ηπ O , made a few years ago, seems to be dissolving. Yet, the evidence for non-qq states is clearly present. Conventional qq nonets are over-subscribed, states have been found with decay modes or production characteristics peculiar for qq. The experimental lesson we have learned is that information from a number of complementary processes must be brought together in order to understand the meson spectrum. Information has come from e + e - ,γγ, γγ, and pp collisions, from vector meson decays and from peripheral and central hadroproduction. This talk will review the status of the experimental search. I will especially point out how new technology is being brought to bear on the re-visit of the light quark sector. New instrumentation allows for sophisticated and selective triggers. The recent explosion in computing power allows us to analyze data with unprecedented statistics. Preliminary results from a recently completed, ultra-high statistics experiment using the Multiparticle Spectrometer at Brookhaven Lab will be presented. I will also describe the extension of the search to CEBAF, where an approved experiment there will study the sub-structure of scalar mesons via the radiative decays of the ER meson

  7. Intense fusion neutron sources

    International Nuclear Information System (INIS)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-01-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 10 15 -10 21 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 10 20 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  8. Intense fusion neutron sources

    Science.gov (United States)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  9. Elemental quantification of airborne particulate matter by instrumental neutron activation analysis and induced coupled plasma mass spectrometry analysis

    International Nuclear Information System (INIS)

    Hidayat, Achmad; Djojosubroto, Harjoto; Rukihati; Sutisna

    1999-01-01

    Airborne particulate were collected using Gent sampler for PM 10 and using high volume sampler for total suspended particulate (TSP). PM 10 sampling was carried out in Bandung during period of January to December 1997. Whereas TSP samples were collected at Serpong (rural area) and Jakarta (urban area) during period of May and July 1995. The concentration of the PM 10 in the air is independent to the level of the rainfall. The levels of the PM 10 and the PM 2.5 are lower than the maximum permissible levels set by the US Environmental Protection Agency in July 1997. The element detected using short lived radioactivity measurement in PM 10 and PM 2.5 were Al, Na, V, Mn, Br and Cl. Bromine concentration in both coarse and fine fractions was high, and the enrichment factor for bromine in these fraction was found between 2,000 - 10,000. The elemental concentrations of particulate matter obtained by ICP-MS was found that the Ag, Al, As, Ba, Cd, Co, Cr, Cs, Cu, Fe, In, K, Mg, Mn, Na, Ni, Pb, Rb, V and Zn in samples from Serpong area, were lower than those in samples taken from Jakarta area. The level of Pb concentrations in TSP samples from Serpong and Jakarta area were lower than Pb concentration proposed Indonesian standard of 2 μg/m 3 . The data obtained by INAA no significant different to those obtained by ICP-MS. Therefore comparative data can be obtained by these techniques. (author)

  10. Neutron Stars and Pulsars

    CERN Document Server

    Becker, Werner

    2009-01-01

    Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only review...

  11. Interaction of the radiation with matter

    International Nuclear Information System (INIS)

    2013-01-01

    This third chapter presents the ionization, excitation, activation and radiation breaking; radiation directly and indirectly ionizing; interaction of the electromagnetic radiation with matter; interaction of neutrons with matter; interaction of radiation directly ionizing with matter; interaction of electrons with matter, interaction of alpha particle with matter; interaction of fission fragments with matter; travel time and integrated processes of interaction: energy dissipation

  12. Neutron reflectivity

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.

  13. Dence Cold Matter

    Directory of Open Access Journals (Sweden)

    Stavinskiy Alexey

    2014-04-01

    Full Text Available Possible way to create dense cold baryonic matter in the laboratory is discussed. The density of this matter is comparable or even larger than the density of neutron star core. The properties of this matter can be controlled by trigger conditions. Experimental program for the study of properties of dense cold matter for light and heavy ion collisions at initial energy range √sNN~2-3GeV is proposed..

  14. Dynamics of Soft Matter

    CERN Document Server

    García Sakai, Victoria; Chen, Sow-Hsin

    2012-01-01

    Dynamics of Soft Matter: Neutron Applications provides an overview of neutron scattering techniques that measure temporal and spatial correlations simultaneously, at the microscopic and/or mesoscopic scale. These techniques offer answers to new questions arising at the interface of physics, chemistry, and biology. Knowledge of the dynamics at these levels is crucial to understanding the soft matter field, which includes colloids, polymers, membranes, biological macromolecules, foams, emulsions towards biological & biomimetic systems, and phenomena involving wetting, friction, adhesion, or micr

  15. Neutron detectors for the ESS diffractometers

    Czech Academy of Sciences Publication Activity Database

    Stefanescu, I.; Christensen, M.; Fenske, J.; Hall-Wilton, R.; Henry, P. F.; Kirstein, O.; Muller, M.; Nowak, G.; Pooley, D.; Raspino, D.; Rhodes, N.; Šaroun, Jan; Schefer, J.; Schooneveld, E.; Sykora, J.; Schweika, W.

    2017-01-01

    Roč. 12, JAN (2017), č. článku P01019. ISSN 1748-0221 R&D Projects: GA MŠk LM2015048 Institutional support: RVO:61389005 Keywords : instrumentation for neutron sources * neutron diffraction detectors * neutron detectors (cold, thermal, fast neutrons) Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.220, year: 2016

  16. Biological effects of neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ogiu, Toshiaki; Ohmachi, Yasushi; Ishida, Yuka [National Inst. of Radiological Sciences, Chiba (JP)] [and others

    2003-03-01

    Although the occasion to be exposed to neutrons is rare in our life, except for nuclear accidents like in the critical accident at Tokai-mura in 1999, countermeasures against accident should be always prepared. In the Tokai-mura accident, residents received less than 21 mSv of neutrons and gamma rays. The cancer risks and fetal effects of low doses of neutrons were matters of concern among residents. The purpose of this program is to investigate the relative biological effectiveness (RBE) for leukemias, and thereby to assess risks of neutrons. Animal experiments are planed to obtain the following RBEs: (1) RBE for the induction of leukemias in mice and (2) RBE for effects on fetuses. Cyclotron fast neutrons (10 MeV) and electrostatic accelerator-derived neutrons (2 MeV) are used for exposure in this program. Furthermore, cytological and cytogenetic analyses will be performed. (author)

  17. Prospects of Constraining the Dense Matter Equation of State from Timing Analysis of Pulsars in Double Neutron Star Binaries: The Cases of PSR J0737 ‒ 3039A and PSR J1757 ‒ 1854

    Directory of Open Access Journals (Sweden)

    Manjari Bagchi

    2018-02-01

    Full Text Available The Lense-Thirring effect from spinning neutron stars in double neutron star binaries contributes to the periastron advance of the orbit. This extra term involves the moment of inertia of the neutron stars. The moment of inertia, on the other hand, depends on the mass and spin of the neutron star, as well as the equation of state of the matter. If at least one member of the double neutron star binary (better the faster one is a radio pulsar, then accurate timing analysis might lead to the estimation of the contribution of the Lense-Thirring effect to the periastron advance, which will lead to the measurement of the moment of inertia of the pulsar. The combination of the knowledge on the values of the moment of inertia, the mass and the spin of the pulsar will give a new constraint on the equation of state. Pulsars in double neutron star binaries are the best for this purpose as short orbits and moderately high eccentricities make the Lense-Thirring effect substantial, whereas tidal effects are negligible (unlike pulsars with main sequence or white-dwarf binaries. The most promising pulsars are PSR J0737 − 3039A and PSR J1757 − 1854. The spin-precession of pulsars due to the misalignment between the spin and the orbital angular momentum vectors affect the contribution of the Lense-Thirring effect to the periastron advance. This effect has been explored for both PSR J0737 − 3039A and PSR J1757 − 1854, and as the misalignment angles for both of these pulsars are small, the variation in the Lense-Thirring term is not much. However, to extract the Lense-Thirring effect from the observed rate of the periastron advance, more accurate timing solutions including precise proper motion and distance measurements are essential.

  18. Other applications of neutron beams in material sciences

    International Nuclear Information System (INIS)

    Novion, C.H. de

    1997-01-01

    The various applications of neutron beams are reviewed. The different mechanisms involved in neutron interaction with matter are explained. We notice that generally neutron radiation effects are unfavorable but can be turned into efficient tools to add new structures or properties to materials, silicon doping is an example. The basis principles of neutron activation analysis and neutron radiography are described. (A.C.)

  19. Other applications of neutron beams in material sciences; Autres utilisations des faisceaux de neutrons en science des materiaux

    Energy Technology Data Exchange (ETDEWEB)

    Novion, C.H. de

    1997-12-31

    The various applications of neutron beams are reviewed. The different mechanisms involved in neutron interaction with matter are explained. We notice that generally neutron radiation effects are unfavorable but can be turned into efficient tools to add new structures or properties to materials, silicon doping is an example. The basis principles of neutron activation analysis and neutron radiography are described. (A.C.)

  20. Neutron Star Physics and EOS

    Directory of Open Access Journals (Sweden)

    Lattimer James M.

    2016-01-01

    Full Text Available Neutron stars are important because measurement of their masses and radii will determine the dense matter equation of state. They will constrain the nuclear matter symmetry energy, which controls the neutron star matter pressure and the interior composition, and will influence the interpretation of nuclear experiments. Astrophysical observations include pulsar timing, X-ray bursts, quiescent low-mass X-ray binaries, pulse profiles from millisecond pulsars, neutrino observations from gravitational collapse supernovae,and gravitational radiation from compact object mergers. These observations will also constrain the neutron star interior, including the properties of superfluidity there, and determine the existence of a possible QCD phase transition.

  1. Interpretations of galactic center gamma-ray excess confronting the PandaX-II constraints on dark matter-neutron spin-dependent scatterings in the NMSSM

    Science.gov (United States)

    Shang, Liangliang; He, Yangle; Lian, Jingwei; Pan, Yusi

    2018-05-01

    The Weakly Interacting Massive Particle (WIMP) has been one of the most attractive candidates for Dark Matter (DM), and the lightest neutralino (\\widetilde{χ }^0_1) in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) is an interesting realization of the WIMP framework. The Galactic Center Excess (GCE) indicated from the analysis of the photon data of the Fermi Large Area Telescope (Fermi-LAT) in the gamma-ray wavelength ≲ 1 fm, can be explained by WIMP DM annihilations in the sky, as shown in many existing works. In this work we consider an interesting scenario in the Z_3-NMSSM where the singlet S and Singlino \\widetilde{S}^0 components play important roles in the Higgs and DM sector. Guided by our analytical arguments, we perform a sophisticated scan over the NMSSM parameter space by considering various observables such as the Standard Model (SM) Higgs data measured by the ATLAS and CMS experiments at the Large Hadron Collider (LHC), and the B-physics observables BR(B_s→ X_sγ ) and BR(B_s→ μ ^+μ ^-). We first collect samples which can explain the GCE well while passing all constraints we consider except for the DM direct detection (DD) bounds from XENON1T and PandaX-II experiments. We analyze the features of these samples suitable for the GCE interpretation and find that \\widetilde{χ }^0_1 DM are mostly Singlino-like and annihilation products are mostly the bottom quark pairs \\bar{b}b through a light singlet-like CP-odd Higgs A_1. Moreover, a good fit to the GCE spectrum generically requires sizable DM annihilation rates 0 in today's Universe. However, the correlation between the coupling C_{A_1 b\\bar{b}} in 0 and the coupling C_{Z \\widetilde{χ }^0_1 \\widetilde{χ }^0_1} in DM-neutron Spin Dependent (SD) scattering rate σ ^{SD}_{\\widetilde{χ }^0_1-N} makes all samples we obtain for GCE explanation get excluded by the PandaX-II results. Although the DM resonant annihilation scenarios may be beyond the reach of our analytical

  2. BR2 reactor neutron beams

    International Nuclear Information System (INIS)

    Neve de Mevergnies, M.

    1977-01-01

    The use of reactor neutron beams is becoming increasingly more widespread for the study of some properties of condensed matter. It is mainly due to the unique properties of the ''thermal'' neutrons as regards wavelength, energy, magnetic moment and overall favorable ratio of scattering to absorption cross-sections. Besides these fundamental reasons, the impetus for using neutrons is also due to the existence of powerful research reactors (such as BR2) built mainly for nuclear engineering programs, but where a number of intense neutron beams are available at marginal cost. A brief introduction to the production of suitable neutron beams from a reactor is given. (author)

  3. Pulsed spallation Neutron Sources

    International Nuclear Information System (INIS)

    Carpenter, J.M.

    1994-01-01

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology

  4. Pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Carpenter, J.M.

    1996-01-01

    This paper reviews the early history of pulsed spallation neutron source development ar Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provide a few examples of applications in fundamental condensed matter physics, materials science and technology

  5. Nuclear polarization and neutrons

    International Nuclear Information System (INIS)

    Glaettli, H.

    1985-01-01

    Different possibilities for the use of polarized nuclei in thermal neutron scattering on condensed matter are reviewed. Highly polarized nuclei are the starting point for studying dipolar magnetic order. Systematic measurement of spin-dependent scattering lengths is possible on samples with polarized nuclei. Highly polarized hydrogen should help to unravel complicated structures in chemistry and biology. The use of polarized proton targets as an energy-independent neutron polarizer in the thermal and epithermal region should be considered afresh. (author)

  6. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

    A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

  7. Monte-Carlo method for studying the slowing down of neutrons in a thin plate of hydrogenated matter; Methode de Monte-Carlo pour l'etude du ralentissement des neutrons dans une plaque mince de matiere hydrogenee

    Energy Technology Data Exchange (ETDEWEB)

    Ribon, P; Michaudon, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The studies of interaction of slow neutrons with atomic nuclei by means of the time of flight methods are made with a pulsed neutron source with a broad energy spectrum. The measurement accuracy needs a high intensity and an output time as short as possible and well defined. If the neutrons source is a target bombarded by the beam of a pulsed accelerator, it is usually required to slow down the neutrons to obtain a sufficient intensity at low energies. The purpose of the Monte-Carlo method which is described in this paper is to study the slowing down properties, mainly the intensity and the output time distribution of the slowed-down neutrons. The choice of the method and parameters studied is explained as well as the principles, some calculations and the program organization. A few results given as examples were obtained in the line of this program, the limits of which are principally due to simplifying physical hypotheses. (author) [French] l'etude de l'interaction des neutrons lents avec les noyaux atomiques par la methode du temps de vol s'effectue avec une source pulsee de neutrons dont le spectre en energie est assez etendu. La precision des mesures demande que la source soit intense et que la duree d'emission des neutrons soit breve et bien definie. Si la source est une cible bombardee par le faisceau de particules d'un accelerateur pulse, il est generalement indispensable de ralentir les neutrons pour avoir une intensite suffisante a basse energie. Nous presentons ici une methode de Monte-Carlo pour l'etude detaillee de ce ralentissement, notamment l'intensite et la distribution des temps de sortie des neutrons ralentis. Cette presentation comprend: la justification du choix de la methode de Monte-Carlo, les principes generaux, les differentes etapes du calcul et du programme ecrit pour le calculateur electronique IBM 7090. Nous indiquons aussi les restrictions qui sont apportees au domaine d'application de ce programme et qui proviennent surtout des

  8. Neutron imaging plates

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1995-01-01

    Imaging plates have been used in the field of medical diagnosis since long ago, but their usefulness was verified as the two-dimensional detector for analyzing the X-ray crystalline structure of high bio molecules like protein, and they have contributed to the remarkable progress in this field. The great contribution is due to the excellent features, such as the detection efficiency of about 100%, the positional resolution smaller than 0.2 mm, the dynamic range of five digits, and the area of several hundreds mm square. The neutron imaging plates have not yet obtained the sufficient results. It was planned to construct the neutron diffractometer for biological matters, and to put imaging plate neutron detectors (IP-ND) to practical use as the detector. The research on the development of IP-NDs was carried out, and the IPp-NDs having the performance comparable with that for X-ray were able to be produced. Imaging plates are the integral type two-dimensional radiation detector using photostimulated luminescence matters, and their principle is explained. As to neutron imaging plates, the converter, neutron detection efficiency and the flight of secondary particles in photo-stimulated luminescence matters are described. As for the present state of development of neutron imaging plates, the IP-NDs made for trial, the dynamic range, the positional resolution, the detection efficiency and the kinds of converters, and the application of IP-NDs are reported. (K.I.)

  9. Thermal neutron source study

    International Nuclear Information System (INIS)

    Holden, T.M.

    1983-05-01

    The value of intense neutron beams for condensed matter research is discussed with emphasis on the complementary nature of steady state and pulsed neutron sources. A large body of information on neutron sources, both existing and planned, is then summarized under four major headings: fission reactors, electron accelerators with heavy metal targets, pulsed spallation sources and 'steady state' spallation sources. Although the cost of a spallation source is expected to exceed that of a fission reactor of the same flux by a factor of two, there are significant advantages for a spallation device such as the proposed Electronuclear Materials Test Facility (EMTF)

  10. Deep inelastic neutron scattering

    International Nuclear Information System (INIS)

    Mayers, J.

    1989-03-01

    The report is based on an invited talk given at a conference on ''Neutron Scattering at ISIS: Recent Highlights in Condensed Matter Research'', which was held in Rome, 1988, and is intended as an introduction to the techniques of Deep Inelastic Neutron Scattering. The subject is discussed under the following topic headings:- the impulse approximation I.A., scaling behaviour, kinematical consequences of energy and momentum conservation, examples of measurements, derivation of the I.A., the I.A. in a harmonic system, and validity of the I.A. in neutron scattering. (U.K.)

  11. Bibliography for thermal neutron scattering

    International Nuclear Information System (INIS)

    Sakamoto, M.; Chihara, J.; Nakahara, Y.; Kadotani, H.; Sekiya, T.

    1976-12-01

    It contains bibliographical references to measurements, calculations, reviews and basic studies on thermal neutron scatterings and dynamical properties of condensed matter. About 2,700 documents up to the end of 1975 are covered. (auth.)

  12. The quark matter

    International Nuclear Information System (INIS)

    Rho, Mannque.

    1980-04-01

    The present status of our understanding of the physics of hadronic (nuclear or neutron) matter under extreme conditions, in particular at high densities is discussed. This is a problem which challenges three disciplines of physics: nuclear physics, astrophysics and particle physics. It is generally believed that we now have a correct and perhaps ultimate theory of the strong interactions, namely quantum chromodynamics (QCD). The constituents of this theory are quarks and gluons, so highly dense matters should be describable in terms of these constituents alone. This is a question that addresses directly to the phenomenon of quark confinement, one of the least understood aspects in particle physics. For nuclear physics, the possibility of a phase change between nuclear matter and quark matter introduces entirely new degrees of freedom in the description of nuclei and will bring perhaps a deeper understanding of nuclear dynamics. In astrophysics, the properties of neutron stars will be properly understood only when the equation of state of 'neutron' matter at densities exceeding that of nuclear matter can be realiably calculated. Most fascinating is the possibility of quark stars existing in nature, not entirely an absurd idea. Finally the quark matter - nuclear matter phase transition must have occured in the early stage of universe when matter expanded from high temperature and density; this could be an essential ingredient in the big-bang cosmology

  13. Physics of Neutron Star Crusts

    Directory of Open Access Journals (Sweden)

    Chamel Nicolas

    2008-12-01

    Full Text Available The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.

  14. Neutron scattering: history, present state and perspectives

    International Nuclear Information System (INIS)

    Belushkin, A.V.

    1999-01-01

    The paper reminds some milestones in development of condensed matter research with neutrons. Present status of the investigations in this field is briefly outlined. An analysis is given on the situation and future prospects in different neutron sources development in Russia and in the world. The next generation neutron sources projects in Japan, USA and Europe are reviewed

  15. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

    Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

  16. The advanced neutron source

    International Nuclear Information System (INIS)

    Hayter, J.B.

    1994-01-01

    The Advanced Neutron Source (ANS), slated for construction start in 1994, will be a multipurpose neutron research laboratory serving academic and industrial users in chemistry, biology, condensed matter physics, nuclear and fundamental physics, materials science and engineering, and many other fields. It will be centered on the world's highest flux neutron beam reactor, operating at 330 MW, with careful design integration between the neutron source and the experiment systems. Many instruments will be situated in low backgrounds at distances up to 80 m from the reactor, using neutron guides with tailored neutron optical coatings for beam transport. Apart from the many stations for neutron scattering research, specialized stations will also be provided for isotope separation on-line, experiments with liquid hydrogen targets, neutron optical techniques such as interferometry, activation analysis, depth profiling, and positron production. Careful consideration has been given to providing a good research environment for visiting scientists, including easy access to the experimental areas, while maintaining a highly secure nuclear facility. This paper will describe the reactor and experimental facilities and give some examples of the types of research for which ANS has been designed

  17. American Conference on Neutron Scattering 2014

    International Nuclear Information System (INIS)

    Dillen, J. Ardie

    2014-01-01

    Scientists from the around the world converged in Knoxville, TN to have share ideas, present technical information and contribute to the advancement of neutron scattering. Featuring over 400 oral/poster presentations, ACNS 2014 offered a strong program of plenary, invited and contributed talks and poster sessions covering topics in soft condensed matter, hard condensed matter, biology, chemistry, energy and engineering applications in neutron physics - confirming the great diversity of science that is enabled by neutron scattering.

  18. American Conference on Neutron Scattering 2014

    Energy Technology Data Exchange (ETDEWEB)

    Dillen, J. Ardie [Materials Research Society, Warrendale, PA (United States)

    2014-12-31

    Scientists from the around the world converged in Knoxville, TN to have share ideas, present technical information and contribute to the advancement of neutron scattering. Featuring over 400 oral/poster presentations, ACNS 2014 offered a strong program of plenary, invited and contributed talks and poster sessions covering topics in soft condensed matter, hard condensed matter, biology, chemistry, energy and engineering applications in neutron physics – confirming the great diversity of science that is enabled by neutron scattering.

  19. Neutron star structure from QCD

    CERN Document Server

    Fraga, Eduardo S; Vuorinen, Aleksi

    2016-01-01

    In this review article, we argue that our current understanding of the thermodynamic properties of cold QCD matter, originating from first principles calculations at high and low densities, can be used to efficiently constrain the macroscopic properties of neutron stars. In particular, we demonstrate that combining state-of-the-art results from Chiral Effective Theory and perturbative QCD with the current bounds on neutron star masses, the Equation of State of neutron star matter can be obtained to an accuracy better than 30% at all densities.

  20. ACCELERATING COMPACT OBJECT MERGERS IN TRIPLE SYSTEMS WITH THE KOZAI RESONANCE: A MECHANISM FOR 'PROMPT' TYPE Ia SUPERNOVAE, GAMMA-RAY BURSTS, AND OTHER EXOTICA

    International Nuclear Information System (INIS)

    Thompson, Todd A.

    2011-01-01

    White dwarf-white dwarf (WD-WD) and neutron star-neutron star (NS-NS) mergers may produce Type Ia supernovae and gamma-ray bursts (GRBs), respectively. A general problem is how to produce binaries with semi-major axes small enough to merge in significantly less than the Hubble time (t H ), and thus accommodate the observation that these events closely follow episodes of star formation. I explore the possibility that such systems are not binaries at all, but actually coeval, or dynamical formed, triple systems. The tertiary induces Kozai oscillations in the inner binary, driving it to high eccentricity, and reducing its gravitational wave (GW) merger timescale. This effect significantly increases the allowed range of binary period P such that the merger time is t merge H . In principle, Chandrasekhar-mass binaries with P ∼ 300 days can merge in ∼ H if they contain a prograde solar-mass tertiary at high enough inclination. For retrograde tertiaries, the maximum P such that t merge ∼ H is yet larger. In contrast, P ∼< 0.3 days is required in the absence of a tertiary. I discuss implications of these findings for the production of transients formed via compact object binary mergers. Based on the statistics of solar-type binaries, I argue that many such binaries should be in triple systems affected by the Kozai resonance. If true, expectations for the mHz GW signal from individual sources, the diffuse background, and the foreground for GW experiments like LISA are modified. This work motivates future studies of triples systems of A, B, and O stars, and new types of searches for WD-WD binaries in triple systems.

  1. Transport properties of dense matter

    International Nuclear Information System (INIS)

    Itoh, Naoki; Mitake, Shinichi; Iyetomi, Hiroshi; Ichimaru, Setsuo

    1983-01-01

    Transport coefficients, electrical and thermal conductivities in particular, are essential physical quantities for the theories of stellar structure. Since the discoveries of pulsars and X-ray stars, an accurate evaluation of the transport coefficients in the dense matter has become indispensable to the quantitative understanding of the observed neutron stars. The authors present improved calculations of the electrical and thermal conductivities of the dense matter in the liquid metal phase, appropriate to white dwarfs and neutron stars. (Auth.)

  2. Spallation Neutron Sources For Science And Technology

    International Nuclear Information System (INIS)

    Comsan, M.N.H.

    2011-01-01

    Spallation Neutron Facilities Increasing interest has been noticed in spallation neutron sources (SNS) during the past 20 years. The system includes high current proton accelerator in the GeV region and spallation heavy metal target in the Hg-Bi region. Among high flux currently operating SNSs are: ISIS in UK (1985), SINQ in Switzerland (1996), JSNS in Japan (2008), and SNS in USA (2010). Under construction is the European spallation source (ESS) in Sweden (to be operational in 2020). The intense neutron beams provided by SNSs have the advantage of being of non-reactor origin, are of continuous (SINQ) or pulsed nature. Combined with state-of-the-art neutron instrumentation, they have a diverse potential for both scientific research and diverse applications. Why Neutrons? Neutrons have wavelengths comparable to interatomic spacings (1-5 A) Neutrons have energies comparable to structural and magnetic excitations (1-100 meV) Neutrons are deeply penetrating (bulk samples can be studied) Neutrons are scattered with a strength that varies from element to element (and isotope to isotope) Neutrons have a magnetic moment (study of magnetic materials) Neutrons interact only weakly with matter (theory is easy) Neutron scattering is therefore an ideal probe of magnetic and atomic structures and excitations Neutron Producing Reactions Several nuclear reactions are capable of producing neutrons. However the use of protons minimises the energetic cost of the neutrons produced solid state physics and astrophysics Inelastic neutron scattering

  3. Outline of spallation neutron source engineering

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Noboru [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2001-01-01

    Slow neutrons such as cold and thermal neutrons are unique probes which can determine structures and dynamics of condensed matter in atomic scale. The neutron scattering technique is indispensable not only for basic sciences such as condensed matter research and life science, but also for basic industrial technology in 21 century. It is believed that to survive in the science-technology competition in 21 century would be almost impossible without neutron scattering. However, the intensity of neutrons presently available is much lower than synchrotron radiation sources, etc. Thus, R and D of intense neutron sources become most important. The High-Intensity Proton Accelerator Project is now being promoted jointly by Japan Atomic Energy Research Institute and High Energy Accelerator Research Organization, but there has so far been no good text which covers all the aspects of pulsed spallation neutron sources. The present review was prepare aiming at giving a better understanding on pulsed spallation neutron sources not only to neutron source researchers but also more widely to neutron scattering researchers and accelerator scientists in this field. The contents involve, starting from what is neutron scattering and what neutrons are necessary for neutron scattering, what is the spallation reaction, how to produce neutrons required for neutron scattering more efficiently, target-moderator-reflector neutronics and its engineering, shielding, target station, material issues, etc. The author have engaged in R and D of pulsed apallation neutron sources and neutron scattering research using them over 30 years. The present review is prepared based on the author's experiences with useful information obtained through ICANS collaboration and recent data from the JSNS (Japanese Spallation Neutron Source) design team. (author)

  4. Structure and stability of warm cores in neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez Cabanell, J M [Departamento de Mecanica y Astronomia, Facultad de Matematicas, Burjasot-Valencia (Spain)

    1981-12-01

    Relativistic equations of structure are solved using Lamb's equations of state for warm neutron degenerate matter. The stability of isothermal cores in neutron stars is discussed and also the possible compatibility of the results obtained with experimental evidence is shown.

  5. Flipped neutrino emissivity from strange matter

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, A.; Dutta, S. (Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India))

    1994-04-15

    Energy loss due to wrong helicity sterile neutrinos through spin flip processes leads to rapid cooling of nascent neutron stars. The observed cooling of neutron stars associated with SN 1987A seems to preclude the existence of Dirac neutrinos with a mass in excess of 20 keV. Assuming that nuclear matter in the core of the neutron star undergoes a phase transition to quark matter leading to a strange star or a neutron star with a strange matter core, we examine the emission of flipped Dirac neutrinos for two dominant processes: quark-neutrino scattering [[ital q]+[nu][sub [minus

  6. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  7. Neutron background estimates in GESA

    Directory of Open Access Journals (Sweden)

    Fernandes A.C.

    2014-01-01

    Full Text Available The SIMPLE project looks for nuclear recoil events generated by rare dark matter scattering interactions. Nuclear recoils are also produced by more prevalent cosmogenic neutron interactions. While the rock overburden shields against (μ,n neutrons to below 10−8 cm−2 s−1, it itself contributes via radio-impurities. Additional shielding of these is similar, both suppressing and contributing neutrons. We report on the Monte Carlo (MCNP estimation of the on-detector neutron backgrounds for the SIMPLE experiment located in the GESA facility of the Laboratoire Souterrain à Bas Bruit, and its use in defining additional shielding for measurements which have led to a reduction in the extrinsic neutron background to ∼ 5 × 10−3 evts/kgd. The calculated event rate induced by the neutron background is ∼ 0,3 evts/kgd, with a dominant contribution from the detector container.

  8. Epithermal neutron instrumentation at ISIS

    International Nuclear Information System (INIS)

    Gorini, G; Festa, G; Andreani, C

    2014-01-01

    The advent of pulsed neutron sources makes available high epithermal neutron fluxes (in the energy range between 500 meV and 100 eV). New dedicated instrumentation, such as Resonance Detectors, was developed at ISIS spallation neutron source in the last years to apply the specific properties of this kind of neutron beam to the study of condensed matter. New detection strategies like Filter Difference method and Foil Cycling Technique were also developed in parallel to the detector improvement at the VESUVIO beamline. Recently, epithermal neutron beams were also used at the INES beamline to study elemental and isotopic composition of materials, with special application to cultural heritage studies. In this paper we review a series of epithermal neutron instrumentation developed at ISIS, their evolution over time and main results obtained

  9. Assessment of occupational exposure and contamination by means of airborne particulate matter and biomonitors using k0 instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Menezes, M.A. de B.C.; Pereira Maia, E.C.; Filho, S.S.; Albinati, C.

    2002-01-01

    In order to assess the elemental concentration level in a galvanizing industry and alert for the need to assess the outcome of a long-term exposure, scalp hair and toenail samples were used as bioindicators and the industry environment was evaluated through airborne particulate matter. The elemental concentration results have pointed out a high exposure to pollutant at workplaces and a high elemental concentration in biomonitors suggesting endogenous contamination. The majority of the elements determined in airborne particulate matter were also determined in hair and toenail samples. The results evidence the efficiency of these matrixes as biomonitors and the importance to carry out the airborne particulate matter sampling in parallel to these biomonitors mainly in occupational epidemiological studies. (author)

  10. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

    The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

  11. How neutron stars constrain the nuclear equation of state

    Directory of Open Access Journals (Sweden)

    Hell Thomas

    2014-03-01

    Full Text Available Recent neutron star observations set new constraints for the equation of state of baryonic matter. A chiral effective field theory approach is used for the description of neutron-dominated nuclear matter present in the outer core of neutron stars. Possible hybrid stars with quark matter in the inner core are discussed using a three-flavor Nambu–Jona-Lasinio model.

  12. Neutron Star Interiors and Topology Change

    Directory of Open Access Journals (Sweden)

    Peter K. F. Kuhfittig

    2013-01-01

    Full Text Available Quark matter is believed to exist in the center of neutron stars. A combined model consisting of quark matter and ordinary matter is used to show that the extreme conditions existing in the center could result in a topology change, that is, in the formation of wormholes.

  13. Slow neutron scattering experiments

    International Nuclear Information System (INIS)

    Moon, R.M.

    1985-01-01

    Neutron scattering is a versatile technique that has been successfully applied to condensed-matter physics, biology, polymer science, chemistry, and materials science. The United States lost its leadership role in this field to Western Europe about 10 years ago. Recently, a modest investment in the United States in new facilities and a positive attitude on the part of the national laboratories toward outside users have resulted in a dramatic increase in the number of US scientists involved in neutron scattering research. Plans are being made for investments in new and improved facilities that could return the leadership role to the United States. 23 references, 4 figures, 3 tables

  14. Imaging with Polarized Neutrons

    Directory of Open Access Journals (Sweden)

    Nikolay Kardjilov

    2018-01-01

    Full Text Available Owing to their zero charge, neutrons are able to pass through thick layers of matter (typically several centimeters while being sensitive to magnetic fields due to their intrinsic magnetic moment. Therefore, in addition to the conventional attenuation contrast image, the magnetic field inside and around a sample can be visualized by detecting changes of polarization in a transmitted beam. The method is based on the spatially resolved measurement of the cumulative precession angles of a collimated, polarized, monochromatic neutron beam that traverses a magnetic field or sample.

  15. Expectations for neutrons as microscopic probes

    International Nuclear Information System (INIS)

    Date, M.

    1993-01-01

    Neutrons have been used as microscopic probes to study structural and dynamical properties of various materials. In this paper I shall give a comparative study of the neutron research in the condensed matter physics with other typical microscopic methods such as X-rays, laser optics, magnetic resonances, Moessbauer effect and μSR. It is emphasized that the neutron study will extensively be important in future beyond the condensed matter physics. Chemistry, biology, earth sciences, material engineerings and medical sciences will become new frontiers for neutron study. (author)

  16. Nucleons, Nuclear Matter and Quark Matter: A unified NJL approach

    Energy Technology Data Exchange (ETDEWEB)

    S. Lawley; W. Bentz; A.W. Thomas

    2006-02-10

    We use an effective quark model to describe both hadronic matter and deconfined quark matter. By calculating the equations of state and the corresponding neutron star properties, we show that the internal properties of the nucleon have important implications for the properties of these systems.

  17. Nucleons, nuclear matter and quark matter: a unified NJL approach

    Energy Technology Data Exchange (ETDEWEB)

    Lawley, S [Special Research Centre for the Subatomic Structure of Matter, University of Adelaide, Adelaide SA 5005 (Australia); Bentz, W [Department of Physics, School of Science, Tokai University Hiratsuka-shi, Kanagawa 259-1292 (Japan); Thomas, A W [Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

    2006-05-01

    We use an effective quark model to describe both hadronic matter and deconfined quark matter. By calculating the equations of state and the corresponding neutron star properties, we show that the internal properties of the nucleon have important implications for the properties of these systems.

  18. Condensed matter physics

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The condensed matter physics research in the Physics Department of Risoe National Laboratory is predominantly experimental utilising diffraction of neutrons and x-rays. The research topics range from studies of structure, excitations and phase transitions in model systems to studies of ion transport, texture and recrystallization kinetics with a more applied nature. (author)

  19. The world’s first pelletized cold neutron moderator at a neutron scattering facility

    Energy Technology Data Exchange (ETDEWEB)

    Ananiev, V.; Belyakov, A.; Bulavin, M.; Kulagin, E.; Kulikov, S.; Mukhin, K.; Petukhova, T.; Sirotin, A.; Shabalin, D.; Shabalin, E.; Shirokov, V.; Verhoglyadov, A., E-mail: verhoglyadov_al@mail.ru

    2014-02-01

    In July 10, 2012 cold neutrons were generated for the first time with the unique pelletized cold neutron moderator CM-202 at the IBR-2M reactor. This new moderator system uses small spherical beads of a solid mixture of aromatic hydrocarbons (benzene derivatives) as the moderating material. Aromatic hydrocarbons are known as the most radiation-resistant hydrogenous substances and have properties to moderate slow neutrons effectively. Since the new moderator was put into routine operation in September 2013, the IBR-2 research reactor of the Frank Laboratory of Neutron Physics has consolidated its position among the world’s leading pulsed neutron sources for investigation of matter with neutron scattering methods.

  20. The Dark Side of Neutron Stars

    DEFF Research Database (Denmark)

    Kouvaris, Christoforos

    2013-01-01

    We review severe constraints on asymmetric bosonic dark matter based on observations of old neutron stars. Under certain conditions, dark matter particles in the form of asymmetric bosonic WIMPs can be eectively trapped onto nearby neutron stars, where they can rapidly thermalize and concentrate...... in the core of the star. If some conditions are met, the WIMP population can collapse gravitationally and form a black hole that can eventually destroy the star. Based on the existence of old nearby neutron stars, we can exclude certain classes of dark matter candidates....

  1. Neutron Dosimetry

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2001-01-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding

  2. Neutron Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F

    2001-04-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding.

  3. Introduction to neutron scattering. Lecture notes of the introductory course

    International Nuclear Information System (INIS)

    Furrer, A.

    1996-01-01

    These proceedings enclose ten papers presented at the 1. European Conference on Neutron scattering (ECNS '96). The aim of the Introductory Course was fourfold: - to learn the basic principles of neutron scattering, - to get introduced into the most important classes of neutron scattering instruments, -to learn concepts and their transformation into neutron scattering experiments in various fields of condensed matter research, - to recognize the limitations of the neutron scattering technique as well as to the complementarity of other methods. figs., tabs., refs

  4. A 15-year forward look at neutron facilities in JINR

    International Nuclear Information System (INIS)

    Aksenov, V.L.

    2017-01-01

    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. [ru

  5. Electron volt neutron spectrometers

    International Nuclear Information System (INIS)

    Pietropaolo, A.; Senesi, R.

    2011-01-01

    The advent of pulsed neutron sources has made available intense fluxes of epithermal neutrons (500 meV ≤E≤100 eV ). The possibility to open new investigations on condensed matter with eV neutron scattering techniques, is related to the development of methods, concepts and devices that drive, or are inspired by, emerging studies at this energy scale. Electron volt spectrometers have undergone continuous improvements since the construction of the first prototype instruments, but in the last decade major breakthroughs have been accomplished in terms of resolution and counting statistics, leading, for example, to the direct measurement of the proton 3-D Born–Oppenheimer potential in any material, or to quantitatively probe nuclear quantum effects in hydrogen bonded systems. This paper reports on the most effective methods and concepts for energy analysis and detection, as well as devices for the optimization of electron volt spectrometers for different applications. This is set in the context of the progress made up to date in instrument development. Starting from early stages of development of the technique, particular emphasis will be given to the Vesuvio eV spectrometer at the ISIS neutron source, the first spectrometer where extensive scientific, as well as research and development programmes have been carried out. The potential offered by this type of instrumentation, from single particle excitations to momentum distribution studies, is then put in perspective into the emerging fields of eV spectroscopy applied to cultural heritages and neutron irradiation effects in electronics. - Highlights: ► Neutron spectrometers at eV energies. ► Methods and techniques for eV neutrons counting at spallation sources. ► Scattering, imaging and radiation hardness tests with multi-eV neutrons.

  6. Neutron radiography

    International Nuclear Information System (INIS)

    Hrdlicka, Z.

    1977-01-01

    Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

  7. Neutron physics entering the 21st century

    International Nuclear Information System (INIS)

    Aksenov, V.L.

    2000-01-01

    The objectives of present-day neutron physics are neutron-aided investigations of fundamental interactions and symmetries, high excited states of nuclei, crystalline and magnetic structures, dynamic excitations in solids and liquids over a wide range of energies. The state-of-art and perspectives of the solution of most topical and principle problems of neutron physics are analyzed. The main conclusion is that neutron physics provides rich information for nuclear particle physics, physics of nucleus, condensed matter physics, chemistry, biology, materials science, and earth sciences. In the next century, however, new higher flux neutron sources must be created. By the year 2010 the number of nuclear reactors used for physical research will reduce to 10-15 reactors over the world. Trends in the development of neutron sources are analyzed. The possibilities of leading neutron research centers in the world are considered and most promising projects of neutron sources are discussed. (author)

  8. Industrial applications of neutron diffraction

    International Nuclear Information System (INIS)

    Felcher, G.P.

    1989-01-01

    Neutron diffraction (or, to be more general, neutron scattering) is a most versatile and universal tool, which has been widely employed to probe the structure, the dynamics and the magnetism of condensed matter. Traditionally used for fundamental research in solid state physics, this technique more recently has been applied to problems of immediate industrial interest, as illustrated in examples covering the main fields of endeavour. 14 refs., 14 figs

  9. Material science and neutron scattering

    International Nuclear Information System (INIS)

    1983-01-01

    Neutron scattering experiments complete and extend the condensed matter studies made with X and gamma rays. Then story show a permanent evolution of the instrumentation, methods and experimental techniques to improve the result quality. This is more especially important as neutron sources are weaker than photon and electron sources. Progress in this research domain is due, in most part, to discovery and development of materials for the different measurement device components [fr

  10. The neutron

    International Nuclear Information System (INIS)

    Kredov, B.M.

    1979-01-01

    The history of the neutron is displayed on the basis of contributions by scientists who produced outstanding results in neutron research (part 1), of summarizing discoveries and theories which led to the discovery of the neutron and the resulting development of nuclear physics (part 2), and of fundamental papers written by Rutherford, Chadwick, Iwanenko, and others (appendix). Of interest to physicists, historians, and students

  11. An introduction to neutron transport

    International Nuclear Information System (INIS)

    Wiesenfeld, Bernard

    2015-01-01

    Neutron transport science is the study of neutron transport in a nuclear reactor and of associated nuclear reactions, notably fission reactions. Heat released by these reactions can be used for several purposes: electricity production, hydrogen production, sea water desalination, urban heating, naval propulsion, space propulsion, and so on. This publication contains the course proposed at Mines ParisTech and at the Arts et Metiers ParisTech. It is an introduction to neutron transport science and aims at presenting fundamental physical principles of this original branch of nuclear physics, a so called 'low energies' branch whereas 'high energy' nuclear physics focuses on elementary particles. It addresses complex computation methods which have been developed during the last decades with computation codes of always higher performance. The first part presents elements of atom physics: origin of matter, properties of nuclei and atoms, notion of quantum mechanics, interaction between radiation and matter (ray absorption, Compton Effect and scattering, photoelectric effect). The second part introduces neutron transport by addressing the following issues: nuclear structure, the various aspects of the interaction between neutrons and matter, the evolution of the reactivity of a reactor in normal operation, the chain fission reaction kinetics, and neutron slowing down. The third part addresses various aspects of neutron transport calculation: expression of neutron assessment, scattering approximation, critical condition of a nuclear reactor, introduction to transport theory, peculiarities of fast breeder reactors. The last chapter 'from theory to practice' addresses the approach of the neutron scientist, proposes an overview of the main calculation codes, and presents fields of application (within or without nuclear fission)

  12. MAGNETIC NEUTRON SCATTERING

    Energy Technology Data Exchange (ETDEWEB)

    ZALIZNYAK,I.A.; LEE,S.H.

    2004-07-30

    Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern

  13. Dark matter in our Galaxy. I

    International Nuclear Information System (INIS)

    Tucker, W.; Tucker, K.

    1989-01-01

    Research concerned with the existence and nature of dark matter is examined. The first evidence of dark matter discovered by Oort in 1932 during the study of galactic rotation and observations by Bahcall in 1984 using tracer stars are discussed. Stars, gas, dust, rocks, white dwarfs, neutron stars, black holes, and red and brown dwarfs are investigated as possible forms of dark matter. The date reveal that gas, dust, neutron stars, black holes, rocks, and comets can not be dark matter; however, brown, red, or white dwarfs could be possible forms of dark matter

  14. Applications of thermal neutron scattering

    International Nuclear Information System (INIS)

    Kostorz, G.

    1978-01-01

    Although in the past neutrons have been used quite frequently in the study of condensed matter, a more recent development has lead to applications of thermal neutron scattering in the investigation of more practical rather than purely academic problems. Physicists, chemists, materials scientists, biologists, and others have recognized and demonstrated that neutron scattering techniques can yield supplementary information which, in many cases, could not be obtained with other methods. The paper illustrates the use of neutron scattering in these areas of applied research. No attempt is made to present all the aspects of neutron scattering which can be found in textbooks. From the vast amount of experimental data, only a few examples are presented for the study of structure and atomic arrangement, ''extended'' structure, and dynamic phenomena in substances of current interest in applied research. (author)

  15. Strange matter and Big Bang helium synthesis

    International Nuclear Information System (INIS)

    Madsen, J.; Riisager, K.

    1985-01-01

    Stable strange quark matter produced in the QCD phase transition in the early universe will trap neutrons and repel protons, thus reducing primordial helium production, Ysub(p). For reasonable values of Ysub(p), the radius of strange droplets must exceed 10 -6 cm if strange matter shall solve the dark-matter problem without spoiling Big Bang helium synthesis. (orig.)

  16. Simulation of neutron background for DINO experiment

    International Nuclear Information System (INIS)

    Meghna, K.K.; Bhattacharjee, Pijushpani; Bhattacharya, Satyaki

    2017-01-01

    Various cosmological observations such as rotation curve of galaxies, gravitational lensing etc. establish the existence of a non-luminous matter known as Dark Matter which constitutes about 27% of the matter content of the universe. Despite the evidence for the existence of dark matter, its constituents are still unknown. In underground laboratories, neutrons can be generated mainly by spontaneous fission of U and radiogenic processes, such as by U / Th (α;n) reactions on the rock materials and by cosmogenic processes, such as interaction of cosmic ray muons with rock and shielding materials. We have estimated the flux of both the cosmogenic and the radiogenic neutrons for Jaduguda laboratory facility

  17. Neutrons and the new Standard Model

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey-Musolf, M.J., E-mail: mjrm@physics.wisc.ed [Department of Physics, University of Wisconsin-Madison, Madison, WI 53706 (United States); Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)

    2009-12-11

    Fundamental symmetry tests with neutrons can provide unique information about whatever will be the new Standard Model of fundamental interactions. I review two aspects of this possibility: searches for the permanent electric dipole moment of the neutron and its relation to the origin of baryonic matter, and precision studies of neutron decay that can probe new symmetries. I discuss the complementarity of these experiments with other low-energy precision tests and high energy collider searches for new physics.

  18. On Fallback Disks around Young Neutron Stars

    Science.gov (United States)

    Alpar, M. Ali; Ertan, Ü.; Erkut, M. H.

    2006-08-01

    Some bound matter in the form of a fallback disk may be an initial parameter of isolated neutron stars at birth, which, along with the initial rotation rate and dipole (and higher multipole) magnetic moments, determines the evolution of neutron stars and the categories into which they fall. This talk reviews the possibilities of fallback disk models in explaining properties of isolated neutron stars of different categories. Recent observations of a fallback disk and observational limits on fallback disks will also be discussed.

  19. Fast neutron dosimetry

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.; Pearson, D.W.

    1991-01-01

    During 1988--1990 the magnetic resonance dosimetry project was completed, as were the 250 MeV proton shielding measurements. The first cellular experiment using human cells in vitro at the 1 GeV electron storage ring was also accomplished. More detail may be found in DOE Report number-sign DOE/EV/60417-002 and the open literature cited in the individual progress subsections. We report Kinetic Energy Released in Matter (KERMA), factor measurements in several elements of critical importance to neutron radiation therapy and radiation protection for space habitation and exploration for neutron energies below 30 MeV. The results of this effort provide the only direct measurements of the oxygen and magnesium kerma factors above 20 MeV neutron energy, and the only measurements of the iron kerma factor above 15 MeV. They provide data of immediate relevance to neutron radiotherapy and impose strict criteria for normalizing and testing nuclear models used to calculate kerma factors at higher neutron energies

  20. Neutron Stars: Laboratories for Fundamental Physics Under ...

    Indian Academy of Sciences (India)

    DEBADES BANDYOPADHYAY

    2017-09-07

    Sep 7, 2017 ... Abstract. We discuss different exotic phases and components of matter from the crust to the core of neutron stars based on theoretical models for equations of state relevant to core collapse supernova simulations and neutron star merger. Parameters of the models are constrained from laboratory ...

  1. The use of neutron activation analysis for particle size fractionation and chemical characterization of trace elements in urban air particulate matter

    International Nuclear Information System (INIS)

    Rizzio, E.; Bergamaschi, G.; Profumo, A.; Gallorini, M.

    2001-01-01

    The concentration of more than 25 trace elements have been determined in total air particulate matter and in the size segregated fractions from the urban area of Pavia (North Italy). The PM10 fraction was also collected and analyzed. A study of the solubility in water and in physiological solution of the trace elements contained in the PM10 was also carried out. The resulting solutions were further submitted to column chromatography using Chelex 100 to perform a preliminary chemical characterization. INAA was used as the main analytical technique. ET-AAS was used for all Pb and Cd measurements and, in some cases, for the analysis of V, Mn, Cu and Ni. (author)

  2. Moments of inertia of neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Greif, Svenja Kim; Hebeler, Kai; Schwenk, Achim [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (Germany)

    2016-07-01

    Neutron stars are unique laboratories for matter at extreme conditions. While nuclear forces provide systematic constraints on properties of neutron-rich matter up to around nuclear saturation density, the composition of matter at high densities is still unknown. Recent precise observations of 2 M {sub CircleDot} neutron stars made it possible to derive systematic constraints on the equation of state at high densities and also neutron star radii. Further improvements of these constraints require the observation of even heavier neutron stars or a simultaneous measurement of mass and radius of a single neutron star. Since the precise measurement of neutron star radii is an inherently difficult problem, the observation of moment of inertia of neutron stars provides a promising alternative, since they can be measured by pulsar timing experiments. We present a theoretical framework that allows to calculate moments of inertia microscopically, we show results based on state of the art equations of state and illustrate how future measurements of moments of inertia allow to constrain the equation of state and other properties of neutron stars.

  3. PREFACE: IUMRS-ICA 2008 Symposium, Sessions 'X. Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science' and 'Y. Frontier of Polymeric Nano-Soft-Materials - Precision Polymer Synthesis, Self-assembling and Their Functionalization'

    Science.gov (United States)

    Takahara, Atsushi; Kawahara, Seiichi

    2009-09-01

    Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science (Symposium X of IUMRS-ICA2008) Toshiji Kanaya, Kohji Tashiro, Kazuo Sakura Keiji Tanaka, Sono Sasaki, Naoya Torikai, Moonhor Ree, Kookheon Char, Charles C Han, Atsushi Takahara This volume contains peer-reviewed invited and contributed papers that were presented in Symposium X 'Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science' at the IUMRS International Conference in Asia 2008 (IUMRS-ICA 2008), which was held on 9-13 December 2008, at Nagoya Congress Center, Nagoya, Japan. Structure analyses of soft materials based on synchrotron radiation (SR) and neutron beam have been developed steadily. Small-angle scattering and wide-angle diffraction techniques clarified the higher-order structure as well as time dependence of structure development such as crystallization and microphase-separation. On the other hand, reflectivity, grazing-incidence scattering and diffraction techniques revealed the surface and interface structural features of soft materials. From the viewpoint of strong interests on the development of SR and neutron beam techniques for soft materials, the objective of this symposium is to provide an interdisciplinary forum for the discussion of recent advances in research, development, and applications of SR and neutron beams to soft matter science. In this symposium, 21 oral papers containing 16 invited papers and 14 poster papers from China, India, Korea, Taiwan, and Japan were presented during the three-day symposium. As a result of the review of poster and oral presentations of young scientists by symposium chairs, Dr Kummetha Raghunatha Reddy (Toyota Technological Institute) received the IUMRS-ICA 2008 Young Researcher Award. We are grateful to all invited speakers and many participants for valuable contributions and active discussions. Organizing committee of Symposium (IUMRS-ICA 2008) Professor Toshiji Kanaya (Kyoto University) Professor Kohji

  4. Small angle scattering from soft matter-application to complex mixed systems; Diffusion de neutrons aux petits angles par la matiere molle-application aux systemes mixtes

    Energy Technology Data Exchange (ETDEWEB)

    Boue, F.; Cousin, F.; Gummel, J.; Carrot, G.; El Harrak, A. [CEA Saclay, Lab. Leon Brillouin, CNRS, 91 - Gif-sur-Yvette (France); Oberdisse, J. [Montpellier-2 Univ., Lab. des Colloides, Verres et Nanomateriaux, UMR 5587, 34 (France)

    2007-09-15

    The advantage of small angle neutron scattering associated with isotopic labelling through deuteration is illustrated in the case of mixed systems, created by associating already well-known systems of characteristic structures; this is also important for applications. Our first mixed system associates charged polymer chains, polyelectrolyte (here polystyrene sulfonate, PSS), with oppositely charged particles, proteins (here lysozyme). Different fractions of deuterated water (D{sub 2}O) mixed with normal water are used to match the scattering length density of the protein or of the polymer in non-deuterated or deuterated version. First, this allows us to separate the protein and the polymer signal: we can then distinguish a case where the structures of each species alone in water are hardly modified by mixing, except for interconnections yielding a gel, and a case inducing complete change into a structure common to both species, made of aggregated globules. Secondly, using, for counter-ions of the poly-ions, deuterated Tetramethylammonium, together with matching both protein and polymer, we establish unambiguously the counter-ion release into the solvent. Thirdly, matching only a fraction of polymer chains, the other being deuterated, we extrapolate at zero deuterated fraction their form factor and describe the chain conformation inside the complexes. Fourthly, we illustrate the possibilities of modelling the signal on a second example of mixed system: a nano-composite made of silica particles surrounded by polymer dispersed into a deuterated polymer matrix. Chains are then visible in such reinforced polymer system, in particular when it is submitted to elongation: we discuss a possible model for an ideal system, introducing the scattering contribution from deformed chains. (authors)

  5. Polarizing beam-splitter device at a pulsed neutron source

    International Nuclear Information System (INIS)

    Itoh, Shinichi; Takeda, Masayasu.

    1996-01-01

    A polarizing beam-splitter device was designed using Fe/Si supermirrors in order to obtain two polarized neutron beam lines, from one unpolarized neutron beam line, with a practical beam size for investigating the properties of condensed matter. This device was mounted after a guide tube at a pulsed neutron source, and its performance was investigated. (author)

  6. Equation of state of dense baryonic matter

    International Nuclear Information System (INIS)

    Weber, F.; Weigel, M.K.

    1989-01-01

    In a previous investigation we treated nuclear matter as well as neutron matter at zero and finite temperatures in the frame of different relativistic field theoretical models, but with the restriction to nucleons as the only present baryons. This approach is extended by including a larger fraction of baryons and mesons, necessary for a description of baryon matter under extreme conditions. The equation of state (EOS) is calculated in both the Hartree and Hartree-Fock (HF) approximations for dense nuclear as well as neutron matter. Self-interactions of the σ field up to fourth order have been taken into account. For the treatment of many-baryon matter in the HF approach the parameters of the theory had to be readjusted. A phase transition of both many-baryon systems (neutron as well as nuclear matter) in the high-pressure and high-energy-density region has been found. (author)

  7. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C [Knoxville, TN; Jardret,; Vincent, D [Powell, TN

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  8. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

    This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

  9. Neutron spectometers

    International Nuclear Information System (INIS)

    Poortmans, F.

    1977-01-01

    Experimental work in the field of low-energy neutron physics can be subdivided into two classes: 1)Study of the decay process of the compound-nucleus state as for example the study of the capture gamma rays and of the neutron induced fission process; 2)Study of the reaction mechanism, mainly by measuring the reaction cross-sections and resonance parameters. These neutron cross-sections and resonance parameters are also important data required for many technological applications especially for reactor development programmes. In general, the second class of experiments impose other requirements on the neutron spectrometer than the first class. In most cases, a better neutron energy resolution and a broader neutron energy range are required for the study of the reaction mechanism than for the study of various aspects of the decay process. (author)

  10. Characterization of weak, fair and strong neutron absorbing materials by means of neutron transmission: Beam hardening effect

    Science.gov (United States)

    Kharfi, F.; Bastuerk, M.; Boucenna, A.

    2006-09-01

    The characterization of neutron absorbing materials as well as quantification of neutron attenuation through matter is very essential in various fields, namely in shielding calculation. The objective of this work is to describe an experimental procedure to be used for the determination of neutron transmission through different materials. The proposed method is based on the relation between the gray value measured on neutron radiography image and the corresponding inducing neutron beam. For such a purpose, three kinds of materials (in shape of plate) were investigated using thermal neutrons: (1) boron-alloyed stainless steel as strong absorber; (2) copper and steel as fair absorbers and (3) aluminum as weak absorber. This work is not limited to the determination of neutron transmission through matters; it is also spread out to the measure of the surface density of the neutron absorbing elements (ρs) as a function of thickness of neutron absorbing material such as boron-alloyed stainless steel. The beam hardening effect depending on material thickness was also studied using the neutron transmission measurements. A theoretical approach was used to interpret the experimental results. The neutron transmission measurements were performed at the Neutron Radiography and Tomography facility of the Atomic Institute of the Austrian Universities in Vienna. Finally, a Maxwellian neutron distribution of incident neutron beam was used in the theoretical calculations of neutron energy shift in order to compare with experiments results. The obtained experimental results are in a good agreement with the developed theoretical approach.

  11. Neutron exposure

    International Nuclear Information System (INIS)

    Prillinger, G.; Konynenburg, R.A. van

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. In chapter 6, LWR-PV neutron transport calculations and dosimetry methods and how they are combined to evaluate the neutron exposure of the steel of pressure vessels are discussed. An effort to correlate neutron exposure parameters with damage is made

  12. Atmospheric neutrons

    International Nuclear Information System (INIS)

    Preszler, A.M.; Moon, S.; White, R.S.

    1976-01-01

    Additional calibrations of the University of California double-scatter neutron and additional analysis corrections lead to the slightly changed neutron fluxes reported here. The theoretical angular distributions of Merker (1975) are in general agreement with our experimental fluxes but do not give the peaks for vertical upward and downward moving neutrons. The theoretical neutron escape current J 2 /sub pi/ (Merker, 1972; Armstrong et al., 1973) is in agreement with the experimental values from 10 to 100 MeV. Our experimental fluxes agree with those of the Kanbach et al. (1974) in the overlap region from 70 to 100 MeV

  13. Neutron Albedo

    CERN Document Server

    Ignatovich, V K

    2005-01-01

    A new, algebraic, method is applied to calculation of neutron albedo from substance to check the claim that use of ultradispersive fuel and moderator of an active core can help to gain in size and mass of the reactor. In a model of isotropic distribution of incident and reflected neutrons it is shown that coherent scattering on separate grains in the case of thermal neutrons increases transport cross section negligibly, however it decreases albedo from a wall of finite thickness because of decrease of substance density. A visible increase of albedo takes place only for neutrons with wave length of the order of the size of a single grain.

  14. Theoretical challenges in neutron scattering

    International Nuclear Information System (INIS)

    Lovesey, S.W.

    1985-07-01

    Topics in the interpretation of neutron scattering experiments from paramagnets and quantum fluids are used to illustrate the puissance of the technique in condensed matter research, and to record some fundamental shortcomings in the available theory of many-particle systems. (author)

  15. Neutron moisture measurement in materials

    International Nuclear Information System (INIS)

    Thony, J.L.

    1985-01-01

    This method is generally used for soil moisture determination but also for moisture in building materials. After a review of neutron interaction with matter (elastic and inelastic scattering, radiative capture and absorption with emission of charged particles) and of the equipment (source, detector and counting), gravimetric and chemical calibration are described and accuracy of measurement is discussed. 5 refs [fr

  16. Bibliography for thermal neutron scattering

    International Nuclear Information System (INIS)

    Sakamoto, Masanobu; Chihara, Junzo; Gotoh, Yorio; Kadotani, Hiroyuki; Sekiya, Tamotsu.

    1979-09-01

    Bibliographic references are given for measurements, calculations, reviews and basic studies of thermal neutron scattering and dynamical properties of condensed matter. This is the sixth edition covering 3,326 articles collected up to 1978. The edition being the final issue of the present bibliography series, a forthcoming edition will be published in a new form of bibliography. (author)

  17. Delta isobars in neutron stars

    Directory of Open Access Journals (Sweden)

    Pagliara Giuseppe

    2015-01-01

    Full Text Available The appearance of delta isobars in beta-stable matter is regulated by the behavior of the symmetry energy at densities larger than saturation density. We show that by taking into account recent constraints on the density derivative of the symmetry energy and the theoretical and experimental results on the excitations of delta isobars in nuclei, delta isobars are necessary ingredients for the equations of state used for studying neutron stars. We analyze the effect of the appearance of deltas on the structure of neutron stars: as in the case of hyperons, matter containing delta is too soft for allowing the existence of 2M⊙ neutron stars. Quark stars on the other hand, could reach very massive configurations and they could form from a process of conversion of hadronic stars in which an initial seed of strangeness appears through hyperons.

  18. Flipped neutrino emissivity from strange matter

    International Nuclear Information System (INIS)

    Goyal, A.; Dutta, S.

    1994-01-01

    Energy loss due to wrong helicity sterile neutrinos through spin flip processes leads to rapid cooling of nascent neutron stars. The observed cooling of neutron stars associated with SN 1987A seems to preclude the existence of Dirac neutrinos with a mass in excess of 20 keV. Assuming that nuclear matter in the core of the neutron star undergoes a phase transition to quark matter leading to a strange star or a neutron star with a strange matter core, we examine the emission of flipped Dirac neutrinos for two dominant processes: quark-neutrino scattering [q+ν - (bar ν + )→q+ν + (bar ν - )] and the quark neutrino pair bremsstrahlung process [q+q→q+q+ν - bar ν - (ν+bar ν + )]. We determine the composition of quark matter just after core bounce and examine the effect of neutrino degeneracy on the emission rate and mean free path of the wrong helicity neutrinos

  19. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  20. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1994-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  1. CMS Heavy Flavor spectroscopy and exotica

    CERN Document Server

    Pompili, Alexis

    2016-01-01

    In the last 13 years the discovered quarkonium-like states have renewed the interest in hadron spectroscopy and the LHC experiments are highly contributing to this field.Two relevant contributions by the CMS Collaboration to the exotic heavy flavour spectroscopy are discussed.The first study concerns the production of the $X(3872)$, either prompt or from beauty hadron decays. The cross-section ratio of the $X(3872)$ with respect to the $\\psi(2S)$ in the $J/\\psi \\pi \\pi$ decay channel and the fraction of $X(3872)$ coming from \\textit{B}-hadron decays are measured as a function of transverse momentum ($p_{T}$), covering unprecedentedly high values of $p_{T}$. Moreover the prompt $X(3872)$ cross section times branching fraction is extracted differentially in $p_{T}$, for the first time in central rapidity region, and compared to the theoretical predictions available. Finally the dipion invariant mass spectrum of the $J/\\psi \\pi \\pi$ system, in the $X(3872)$ decay, is also investigated.The second study concerns t...

  2. QCD spectroscopy at GSI: exotica and charmonia

    International Nuclear Information System (INIS)

    Barnes, T.; Tennessee Univ., Knoxville, TN

    2001-01-01

    In this talk I give a short summary of the basics of conventional and exotic meson spectroscopy, and consider in particular those issues in the charmonium and charmonium hybrid sectors which can be addressed by a future antiproton facility at GSI. (orig.)

  3. From hadrons to quarks in neutron stars: a review

    Science.gov (United States)

    Baym, Gordon; Hatsuda, Tetsuo; Kojo, Toru; Powell, Philip D.; Song, Yifan; Takatsuka, Tatsuyuki

    2018-05-01

    In recent years our understanding of neutron stars has advanced remarkably, thanks to research converging from many directions. The importance of understanding neutron star behavior and structure has been underlined by the recent direct detection of gravitational radiation from merging neutron stars. The clean identification of several heavy neutron stars, of order two solar masses, challenges our current understanding of how dense matter can be sufficiently stiff to support such a mass against gravitational collapse. Programs underway to determine simultaneously the mass and radius of neutron stars will continue to constrain and inform theories of neutron star interiors. At the same time, an emerging understanding in quantum chromodynamics (QCD) of how nuclear matter can evolve into deconfined quark matter at high baryon densities is leading to advances in understanding the equation of state of the matter under the extreme conditions in neutron star interiors. We review here the equation of state of matter in neutron stars from the solid crust through the liquid nuclear matter interior to the quark regime at higher densities. We focus in detail on the question of how quark matter appears in neutron stars, and how it affects the equation of state. After discussing the crust and liquid nuclear matter in the core we briefly review aspects of microscopic quark physics relevant to neutron stars, and quark models of dense matter based on the Nambu–Jona–Lasinio framework, in which gluonic processes are replaced by effective quark interactions. We turn then to describing equations of state useful for interpretation of both electromagnetic and gravitational observations, reviewing the emerging picture of hadron-quark continuity in which hadronic matter turns relatively smoothly, with at most only a weak first order transition, into quark matter with increasing density. We review construction of unified equations of state that interpolate between the reasonably well

  4. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

    A safety rod for a nuclear reactor has an inner end portion having a gamma absorption coefficient and neutron capture cross section approximately equal to those of the adjacent shield, a central portion containing materials of high neutron capture cross section and an outer end portion having a gamma absorption coefficient at least equal to that of the adjacent shield

  5. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

    Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

  6. Neutron holography

    International Nuclear Information System (INIS)

    Beynon, T.D.

    1986-01-01

    the paper concerns neutron holography, which allows an image to be constructed of the surfaces, as well as the interiors, of objects. The technique of neutron holography and its applications are described. Present and future use of the method is briefly outlined. (U.K.)

  7. Neutron stars velocities and magnetic fields

    Science.gov (United States)

    Paret, Daryel Manreza; Martinez, A. Perez; Ayala, Alejandro.; Piccinelli, G.; Sanchez, A.

    2018-01-01

    We study a model that explain neutron stars velocities due to the anisotropic emission of neutrinos. Strong magnetic fields present in neutron stars are the source of the anisotropy in the system. To compute the velocity of the neutron star we model its core as composed by strange quark matter and analice the properties of a magnetized quark gas at finite temperature and density. Specifically we have obtained the electron polarization and the specific heat of magnetized fermions as a functions of the temperature, chemical potential and magnetic field which allow us to study the velocity of the neutron star as a function of these parameters.

  8. Examining the possibility to observe neutron dark decay in nuclei

    Science.gov (United States)

    Pfützner, M.; Riisager, K.

    2018-04-01

    As proposed recently by Fornal and Grinstein, neutrons can undergo a dark matter decay mode which has not yet been observed. Such a decay could explain the existing discrepancy between two different methods of neutron lifetime measurements. If such neutron decay is possible, then it should occur also in nuclei with sufficiently low neutron binding energy. We examine a few nuclear candidates for the dark neutron decay and we consider the possibilities of their experimental identification. In more detail we discuss the case of 11Be which appears as the most promising nucleus for the observation of neutron dark decay.

  9. Examining the possibility to observe neutron dark decay in nuclei

    DEFF Research Database (Denmark)

    Pfutzner, M.; Riisager, K.

    2018-01-01

    also in nuclei with sufficiently low neutron binding energy. We examine a few nuclear candidates for the dark neutron decay and we consider the possibilities of their experimental identification. In more detail we discuss the case of Be-11 which appears as the most promising nucleus for the observation......As proposed recently by Fornal and Grinstein, neutrons can undergo a dark matter decay mode which has not yet been observed. Such a decay could explain the existing discrepancy between two different methods of neutron lifetime measurements. If such neutron decay is possible, then it should occur...... of neutron dark decay....

  10. Cracking on anisotropic neutron stars

    Science.gov (United States)

    Setiawan, A. M.; Sulaksono, A.

    2017-07-01

    We study the effect of cracking of a local anisotropic neutron star (NS) due to small density fluctuations. It is assumed that the neutron star core consists of leptons, nucleons and hyperons. The relativistic mean field model is used to describe the core of equation of state (EOS). For the crust, we use the EOS introduced by Miyatsu et al. [1]. Furthermore, two models are used to describe pressure anisotropic in neutron star matter. One is proposed by Doneva-Yazadjiev (DY) [2] and the other is proposed by Herrera-Barreto (HB) [3]. The anisotropic parameter of DY and HB models are adjusted in order the predicted maximum mass compatible to the mass of PSR J1614-2230 [4] and PSR J0348+0432 [5]. We have found that cracking can potentially present in the region close to the neutron star surface. The instability due cracking is quite sensitive to the NS mass and anisotropic parameter used.

  11. Magnetic properties of strongly asymmetric nuclear matter

    International Nuclear Information System (INIS)

    Kutschera, M.; Wojcik, W.

    1988-01-01

    We investigate stability of neutron matter containing a small proton admixture with respect to spin fluctuations. We establish conditions under which strongly asymmetric nuclear matter could acquire a permanent magnetization. It is shown that if the protons are localized, the system becomes unstable to spin fluctuations for arbitrarily weak proton-neutron spin interactions. For non-localized protons there exists a threshold value of the spin interaction above which the system can develop a spontaneous polarization. 12 refs., 2 figs. (author)

  12. Neutron source

    International Nuclear Information System (INIS)

    Cason, J.L. Jr.; Shaw, C.B.

    1975-01-01

    A neutron source which is particularly useful for neutron radiography consists of a vessel containing a moderating media of relatively low moderating ratio, a flux trap including a moderating media of relatively high moderating ratio at the center of the vessel, a shell of depleted uranium dioxide surrounding the moderating media of relatively high moderating ratio, a plurality of guide tubes each containing a movable source of neutrons surrounding the flux trap, a neutron shield surrounding one part of each guide tube, and at least one collimator extending from the flux trap to the exterior of the neutron source. The shell of depleted uranium dioxide has a window provided with depleted uranium dioxide shutters for each collimator. Reflectors are provided above and below the flux trap and on the guide tubes away from the flux trap

  13. The Diversity of Neutron Stars

    Science.gov (United States)

    Kaplan, David L.

    2004-12-01

    Neutron stars are invaluable tools for exploring stellar death, the physics of ultra-dense matter, and the effects of extremely strong magnetic fields. The observed population of neutron stars is dominated by the >1000 radio pulsars, but there are distinct sub-populations that, while fewer in number, can have significant impact on our understanding of the issues mentioned above. These populations are the nearby, isolated neutron stars discovered by ROSAT, and the central compact objects in supernova remnants. The studies of both of these populations have been greatly accelerated in recent years through observations with the Chandra X-ray Observatory and the XMM-Newton telescope. First, we discuss radio, optical, and X-ray observations of the nearby neutron stars aimed at determining their relation to the Galactic neutron star population and at unraveling their complex physical processes by determining the basic astronomical parameters that define the population---distances, ages, and magnetic fields---the uncertainties in which limit any attempt to derive basic physical parameters for these objects. We conclude that these sources are 1e6 year-old cooling neutron stars with magnetic fields above 1e13 Gauss. Second, we describe the hollow supernova remnant problem: why many of the supernova remnants in the Galaxy have no indication of central neutron stars. We have undertaken an X-ray census of neutron stars in a volume-limited sample of Galactic supernova remnants, and from it conclude that either many supernovae do not produce neutron stars contrary to expectation, or that neutron stars can have a wide range in cooling behavior that makes many sources disappear from the X-ray sky.

  14. Chemical shift of neutron resonances and some ideas on neutron resonances and scattering theory

    International Nuclear Information System (INIS)

    Ignatovich, V.K.; )

    2002-01-01

    The dependence of positions of neutron resonances in nuclei in condensed matter on chemical environment is considered. A possibility of theoretical description of neutron resonances, different from R-matrix theory is investigated. Some contradictions of standard scattering theory are discussed and a new approach without these contradictions is formulated [ru

  15. Quantifying Matter

    CERN Document Server

    Angelo, Joseph A

    2011-01-01

    Quantifying Matter explains how scientists learned to measure matter and quantify some of its most fascinating and useful properties. It presents many of the most important intellectual achievements and technical developments that led to the scientific interpretation of substance. Complete with full-color photographs, this exciting new volume describes the basic characteristics and properties of matter. Chapters include:. -Exploring the Nature of Matter. -The Origin of Matter. -The Search for Substance. -Quantifying Matter During the Scientific Revolution. -Understanding Matter's Electromagnet

  16. Nuclei in a neutron star

    International Nuclear Information System (INIS)

    Oyamatsu, K.; Yamada, M.

    1994-01-01

    We report on the recent progress in understanding the matter in the crust of a neutron star. For nuclides in the outer crust, recently measured masses of neutron-rich nuclei enable us to determine more accurately the stable nuclide as a function of the matter density. In the inner crust, the compressible liquid-drop model predicts successive change of the nuclear shape, from sphere to cylinder, slab, cylindrical hole and spherical hole at densities just before the transition to uniform matter. In order to go beyond the liquiddrop model, we performed the Thomas-Fermi calculation paying special attention to the surface diffuseness, and have recently calculated the shell energies of the non-spherical nuclei. We have found from these studies that all these non-spherical nuclei exist stably in the above order even if we include the surface diffuseness and shell energies. (author)

  17. Neutrons for science

    International Nuclear Information System (INIS)

    Jacrot, B.

    2006-01-01

    In 1967, France and Germany decided to cooperate together for the construction and implementation of a nuclear reactor devoted to research works in physics, chemistry and biology. The Laue-Langevin Institute project was born with the mission of supplying to researchers an intense neutron beam source for the analysis of condensed matter. Great Britain rapidly joined the project, progressively followed by other European countries and making up the Laue-Langevin Institute a successful example of European cooperation. This success demonstrates that such a gathering of forces and competences allow to carry out ambitious projects with the best neutron source in the world. This book tells us the genesis of this project and shows how a suitable organization has permitted to optimize the reactor use. It describes also the portrait of three personalities that have played a key role in this success: J. Horowitz, H. Maier-Leibnitz and L. Neel. (J.S.)

  18. Structure of neutron stars

    International Nuclear Information System (INIS)

    Cheong, C.K.

    1974-01-01

    Structure of neutron stars consisting of a cold and catalyzed superdense matter were investigated by integrating the equations for hydrostatic equilibrium based on the General Relativity theory. The equations of state were obtained with the help of semiempirical nuclear mass formulae. A large phase transition was found between the nuclear and subnuclear density regions. The density phase transition points were calculated as 6.2 x 10 11 and 3.8 x 10 13 g/cm 3 . Due to such a large phase transition, the equation of state practically consists of two parts: The nuclear and subnuclear phases wich are in contact under the thermodynamical equilibrium at the corresponding pressure. Some macroscopic properties of neutron stars are discussed. (Author) [pt

  19. New sources and instrumentation for neutron science

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Alina, E-mail: a.gil@ajd.czest.pl [Faculty of Mathematical and Natural Sciences, JD University, Al. Armii Krajowej 13/15, 42-200 Czestochowa (Poland)

    2011-04-01

    Neutron-scattering research has a lot to do with our everyday lives. Things like medicine, food, electronics, cars and airplanes have all been improved by neutron-scattering research. Neutron research also helps scientists improve materials used in a multitude of different products, such as high-temperature superconductors, powerful lightweight magnets, stronger, lighter plastic products etc. Neutron scattering is one of the most effective ways to obtain information on both, the structure and the dynamics of condensed matter. Most of the world's neutron sources were built decades ago, and although the uses and demand for neutrons have increased throughout the years, few new sources have been built. The new construction, accelerator-based neutron source, the spallation source will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. In this paper it will be described what neutrons are and what unique properties make them useful for science, how spallation source is designed to produce neutron beams and the experimental instruments that will use those beams. Finally, it will be described how past neutron research has affected our everyday lives and what we might expect from the most exciting future applications.

  20. New sources and instrumentation for neutron science

    International Nuclear Information System (INIS)

    Gil, Alina

    2011-01-01

    Neutron-scattering research has a lot to do with our everyday lives. Things like medicine, food, electronics, cars and airplanes have all been improved by neutron-scattering research. Neutron research also helps scientists improve materials used in a multitude of different products, such as high-temperature superconductors, powerful lightweight magnets, stronger, lighter plastic products etc. Neutron scattering is one of the most effective ways to obtain information on both, the structure and the dynamics of condensed matter. Most of the world's neutron sources were built decades ago, and although the uses and demand for neutrons have increased throughout the years, few new sources have been built. The new construction, accelerator-based neutron source, the spallation source will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. In this paper it will be described what neutrons are and what unique properties make them useful for science, how spallation source is designed to produce neutron beams and the experimental instruments that will use those beams. Finally, it will be described how past neutron research has affected our everyday lives and what we might expect from the most exciting future applications.

  1. Virtual experiments: the ultimate aim of neutron ray-tracing simulations

    Czech Academy of Sciences Publication Activity Database

    Lefmann, K.; Willendrup, P.K.; Šaroun, Jan

    2008-01-01

    Roč. 16, 3 & 4 (2008), s. 97-111 ISSN 1023-8166 Institutional research plan: CEZ:AV0Z10480505 Keywords : Monte Carlo simulations * neutron scattering * neutron instrumentation Subject RIV: BM - Solid Matter Physics ; Magnetism

  2. Neutron therapy

    International Nuclear Information System (INIS)

    Riesler, Rudi

    1995-01-01

    Standard radiotherapy uses Xrays or electrons which have low LET (linear energy transfer); in contrast, particles such as neutrons with high LET have different radiobiological responses. In the late 1960s, clinical trials by Mary Catterall at the Hammersmith Hospital in London indicated that fast neutron radiation had clinical advantages for certain malignant tumours. Following these early clinical trials, several cyclotron facilities were built in the 1980s for fast neutron therapy, for example at the University of Washington, Seattle, and at UCLA. Most of these newer machines use extracted cyclotron proton beams in the range 42 to 66 MeV with beam intensities of 15 to 60 microamps. The proton beams are transported to dedicated therapy rooms, where neutrons are produced from beryllium targets. Second-generation clinical trials showed that accurate neutron beam delivery to the tumour site is more critical than for photon therapy. In order to achieve precise beam geometries, the extracted proton beams have to be transported through a gantry which can rotate around the patient and deliver beams from any angle; also the neutron beam outline (''field shape'') must be adjusted to extremely irregular shapes using a flexible collimation system. A therapy procedure has to be appropriately organized, with physicians, radiotherapists, nurses, medical physicists and other staff in attendance; other specialized equipment, such as CT or MRI scanners and radiation simulators must be made available. Neutron therapy is usually performed only in radiation oncology departments of major medical centres

  3. Neutron Skins and Neutron Stars in the Multimessenger Era

    Science.gov (United States)

    Fattoyev, F. J.; Piekarewicz, J.; Horowitz, C. J.

    2018-04-01

    The historical first detection of a binary neutron star merger by the LIGO-Virgo Collaboration [B. P. Abbott et al., Phys. Rev. Lett. 119, 161101 (2017), 10.1103/PhysRevLett.119.161101] is providing fundamental new insights into the astrophysical site for the r process and on the nature of dense matter. A set of realistic models of the equation of state (EOS) that yield an accurate description of the properties of finite nuclei, support neutron stars of two solar masses, and provide a Lorentz covariant extrapolation to dense matter are used to confront its predictions against tidal polarizabilities extracted from the gravitational-wave data. Given the sensitivity of the gravitational-wave signal to the underlying EOS, limits on the tidal polarizability inferred from the observation translate into constraints on the neutron-star radius. Based on these constraints, models that predict a stiff symmetry energy, and thus large stellar radii, can be ruled out. Indeed, we deduce an upper limit on the radius of a 1.4 M⊙ neutron star of R⋆1.4Pb 208 to the symmetry energy, albeit at a lower density, we infer a corresponding upper limit of about Rskin208≲0.25 fm . However, if the upcoming PREX-II experiment measures a significantly thicker skin, this may be evidence of a softening of the symmetry energy at high densities—likely indicative of a phase transition in the interior of neutron stars.

  4. Neutron radiography

    International Nuclear Information System (INIS)

    Alaa eldin, M.T.

    2011-01-01

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H 2 O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  5. Neutronics codes

    International Nuclear Information System (INIS)

    Buckel, G.

    1983-01-01

    The objectives are the development, testing and cultivation of reliable, efficient and user-optimized neutron-physical calculation methods and conformity with users' requirements concerning design of power reactors, planning and analysis of experiments necessary for their protection as well as research on physical key problems. A short outline of available computing programmes for the following objectives is given: - Provision of macroscopic group constants, - Calculation of neutron flux distribution in transport theory and diffusion approximation, - Evaluation of neutron flux-distribution, - Execution of disturbance calculations for the determination reactivity coefficients, and - graphical representation of results. (orig./RW) [de

  6. Evolution of Neutron Stars and Observational Constraints

    Directory of Open Access Journals (Sweden)

    Lattimer J.

    2010-10-01

    Full Text Available The structure and evolution of neutron stars is discussed with a view towards constraining the properties of high density matter through observations. The structure of neutron stars is illuminated through the use of several analytical solutions of Einstein’s equations which, together with the maximally compact equation of state, establish extreme limits for neutron stars and approximations for binding energies, moments of inertia and crustal properties as a function of compactness. The role of the nuclear symmetry energy is highlighted and constraints from laboratory experiments such as nuclear masses and heavy ion collisions are presented. Observed neutron star masses and radius limits from several techniques, such as thermal emissions, X-ray bursts, gammaray flares, pulsar spins and glitches, spin-orbit coupling in binary pulsars, and neutron star cooling, are discussed. The lectures conclude with a discusson of proto-neutron stars and their neutrino signatures.

  7. Kaon condensates, nuclear symmetry energy and cooling of neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Kubis, S. E-mail: kubis@alf.ifj.edu.pl; Kutschera, M

    2003-06-02

    The cooling of neutron stars by URCA processes in the kaon-condensed neutron star matter for various forms of nuclear symmetry energy is investigated. The kaon-nucleon interactions are described by a chiral Lagrangian. Nuclear matter energy is parametrized in terms of the isoscalar contribution and the nuclear symmetry energy in the isovector sector. High density behaviour of nuclear symmetry energy plays an essential role in determining the composition of the kaon-condensed neutron star matter which in turn affects the cooling properties. We find that the symmetry energy which decreases at higher densities makes the kaon-condensed neutron star matter fully protonized. This effect inhibits strongly direct URCA processes resulting in slower cooling of neutron stars as only kaon-induced URCA cycles are present. In contrast, for increasing symmetry energy direct URCA processes are allowed in the almost whole density range where the kaon condensation exists.

  8. Kaon condensates, nuclear symmetry energy and cooling of neutron stars

    International Nuclear Information System (INIS)

    Kubis, S.; Kutschera, M.

    2003-01-01

    The cooling of neutron stars by URCA processes in the kaon-condensed neutron star matter for various forms of nuclear symmetry energy is investigated. The kaon-nucleon interactions are described by a chiral Lagrangian. Nuclear matter energy is parametrized in terms of the isoscalar contribution and the nuclear symmetry energy in the isovector sector. High density behaviour of nuclear symmetry energy plays an essential role in determining the composition of the kaon-condensed neutron star matter which in turn affects the cooling properties. We find that the symmetry energy which decreases at higher densities makes the kaon-condensed neutron star matter fully protonized. This effect inhibits strongly direct URCA processes resulting in slower cooling of neutron stars as only kaon-induced URCA cycles are present. In contrast, for increasing symmetry energy direct URCA processes are allowed in the almost whole density range where the kaon condensation exists

  9. BPS Skyrmions as neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Adam, C., E-mail: adam@fpaxp1.usc.es [Departamento de Física de Partículas, Universidad de Santiago de Compostela and Instituto Galego de Física de Altas Enerxias (IGFAE), E-15782 Santiago de Compostela (Spain); Naya, C.; Sanchez-Guillen, J.; Vazquez, R. [Departamento de Física de Partículas, Universidad de Santiago de Compostela and Instituto Galego de Física de Altas Enerxias (IGFAE), E-15782 Santiago de Compostela (Spain); Wereszczynski, A. [Institute of Physics, Jagiellonian University, Reymonta 4, Kraków (Poland)

    2015-03-06

    The BPS Skyrme model has been demonstrated already to provide a physically intriguing and quantitatively reliable description of nuclear matter. Indeed, the model has both the symmetries and the energy–momentum tensor of a perfect fluid, and thus represents a field theoretic realization of the “liquid droplet” model of nuclear matter. In addition, the classical soliton solutions together with some obvious corrections (spin–isospin quantization, Coulomb energy, proton-neutron mass difference) provide an accurate modeling of nuclear binding energies for heavier nuclei. These results lead to the rather natural proposal to try to describe also neutron stars by the BPS Skyrme model coupled to gravity. We find that the resulting self-gravitating BPS Skyrmions provide excellent results as well as some new perspectives for the description of bulk properties of neutron stars when the parameter values of the model are extracted from nuclear physics. Specifically, the maximum possible mass of a neutron star before black-hole formation sets in is a few solar masses, the precise value of which depends on the precise values of the model parameters, and the resulting neutron star radius is of the order of 10 km.

  10. Neutron scattering

    International Nuclear Information System (INIS)

    Furrer, A.

    1993-01-01

    This report contains the text of 16 lectures given at the Summer School and the report on a panel discussion entitled ''the relative merits and complementarities of x-rays, synchrotron radiation, steady- and pulsed neutron sources''. figs., tabs., refs

  11. Neutron storage

    International Nuclear Information System (INIS)

    Strelkov, A.V.

    2004-01-01

    The report is devoted to neutron storage (NS) and describes the history of experiments on the NS development. Great attention is paid to ultracold neutron (UCN) storage. The experiments on the UCN generation, transport, spectroscopy, storage and detection are described. Experiments on searching the UCN electric-dipole moment and electric charge are continued. Possible using of UCN for studying the nanoparticles is discussed [ru

  12. Neutron radiography

    International Nuclear Information System (INIS)

    Bayon, G.

    1989-01-01

    Neutronography or neutron radiography, a non-destructive test method which is similar in its principle to conventional X-ray photography, presently occupies a marginal position among non-destructive test methods (NDT) (no source of suitable performance or cost). Neutron radiography associated with the ORPHEE reactor permits industrial testing; it can very quickly meet a cost requirement comparable to that of conventional test methods. In 1988, 2500 parts were tested on this unit [fr

  13. Quark Deconfinement in Rotating Neutron Stars

    Directory of Open Access Journals (Sweden)

    Richard D. Mellinger

    2017-01-01

    Full Text Available In this paper, we use a three flavor non-local Nambu–Jona-Lasinio (NJL model, an improved effective model of Quantum Chromodynamics (QCD at low energies, to investigate the existence of deconfined quarks in the cores of neutron stars. Particular emphasis is put on the possible existence of quark matter in the cores of rotating neutron stars (pulsars. In contrast to non-rotating neutron stars, whose particle compositions do not change with time (are frozen in, the type and structure of the matter in the cores of rotating neutron stars depends on the spin frequencies of these stars, which opens up a possible new window on the nature of matter deep in the cores of neutron stars. Our study shows that, depending on mass and rotational frequency, up to around 8% of the mass of a massive neutron star may be in the mixed quark-hadron phase, if the phase transition is treated as a Gibbs transition. We also find that the gravitational mass at which quark deconfinement occurs in rotating neutron stars varies quadratically with spin frequency, which can be fitted by a simple formula.

  14. Neutron detector

    International Nuclear Information System (INIS)

    Endo, Hiroshi.

    1993-01-01

    The device of the present invention detects neutrons in a reactor container under a high temperature and reduces the noise level in an FBR type reactor. That is, the detection section comprises a high heat resistant vessel containing a scintillator therein for detecting neutrons. Neutron signals sent from the detection section are inputted to a neutron measuring section by way of a signal transmission section. The detection section is disposed at the inside of the reactor container. Further, the signal transmission section is connected optically to the detection section. With such a constitution, since the detection section comprising the high temperature resistant vessel is disposed at the inside of the reactor container, neutron fluxes can be detected and measured at high sensitivity even under a high temperature circumstance. Since the signal transmission section is optically connected to the detection section, influence of radiation rays upon transmission of the neutron detection signals can be reduced. Accordingly, the noise level can be kept low. (I.S.)

  15. Neutron Scattering

    International Nuclear Information System (INIS)

    Fayer, Michael J.; Gee, Glendon W.

    2005-01-01

    The neutron probe is a standard tool for measuring soil water content. This article provides an overview of the underlying theory, describes the methodology for its calibration and use, discusses example applications, and identifies the safety issues. Soil water makes land-based life possible by satisfying plant water requirements, serving as a medium for nutrient movement to plant roots and nutrient cycling, and controlling the fate and transport of contaminants in the soil environment. Therefore, a successful understanding of the dynamics of plant growth, nutrient cycling, and contaminant behavior in the soil requires knowledge of the soil water content as well as its spatial and temporal variability. After more than 50 years, neutron probes remain the most reliable tool available for field monitoring of soil water content. Neutron probes provide integrated measurements over relatively large volumes of soil and, with proper access, allow for repeated sampling of the subsurface at the same locations. The limitations of neutron probes include costly and time-consuming manual operation, lack of data automation, and costly regulatory requirements. As more non-radioactive systems for soil water monitoring are developed to provide automated profiling capabilities, neutron-probe usage will likely decrease. Until then, neutron probes will continue to be a standard for reliable measurements of field water contents in soils around the globe

  16. Physics of neutron star interiors

    International Nuclear Information System (INIS)

    Blaschke, D.

    2001-01-01

    Neutron stars are the densest observable bodies in our universe. Born during the gravitational collapse of luminous stars - a birth heralded by spectacular supernova explosions - they open a window on a world where the state of the matter and the strength of the fields are anything but ordinary. This book is a collection of pedagogical lectures on the theory of neutron stars, and especially their interiors, at the forefront of current research. It adresses graduate students and researchers alike, and should be particularly suitable as a text bridging the gap between standard textbook material and the research literature

  17. Neutron-neutron probe for uranium exploration

    International Nuclear Information System (INIS)

    Smith, R.C.

    1979-01-01

    A neutron activation probe for assaying the amount of fissionable isotopes in an ore body is described which comprises a casing which is movable through a borehole in the ore body, a neutron source and a number of delayed neutron detectors arranged colinearly in the casing below the neutron source for detecting delayed neutrons

  18. German neutron scattering conference. Programme and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas (ed.)

    2012-07-01

    The German Neutron Scattering Conference 2012 - Deutsche Neutronenstreutagung DN 2012 offers a forum for the presentation and critical discussion of recent results obtained with neutron scattering and complementary techniques. The meeting is organized on behalf of the German Committee for Research with Neutrons - Komitee Forschung mit Neutronen KFN - by the Juelich Centre for Neutron Science JCNS of Forschungszentrum Juelich GmbH. In between the large European and international neutron scattering conferences ECNS (2011 in Prague) and ICNS (2013 in Edinburgh), it offers the vibrant German and international neutron community an opportunity to debate topical issues in a stimulating atmosphere. Originating from ''BMBF Verbundtreffen'' - meetings for projects funded by the German Federal Ministry of Education and Research - this conference series has a strong tradition of providing a forum for the discussion of collaborative research projects and future developments in the field of research with neutrons in general. Neutron scattering, by its very nature, is used as a powerful probe in many different disciplines and areas, from particle and condensed matter physics through to chemistry, biology, materials sciences, engineering sciences, right up to geology and cultural heritage; the German Neutron Scattering Conference thus provides a unique chance for exploring interdisciplinary research opportunities. It also serves as a showcase for recent method and instrument developments and to inform users of new advances at neutron facilities.

  19. German neutron scattering conference. Programme and abstracts

    International Nuclear Information System (INIS)

    Brueckel, Thomas

    2012-01-01

    The German Neutron Scattering Conference 2012 - Deutsche Neutronenstreutagung DN 2012 offers a forum for the presentation and critical discussion of recent results obtained with neutron scattering and complementary techniques. The meeting is organized on behalf of the German Committee for Research with Neutrons - Komitee Forschung mit Neutronen KFN - by the Juelich Centre for Neutron Science JCNS of Forschungszentrum Juelich GmbH. In between the large European and international neutron scattering conferences ECNS (2011 in Prague) and ICNS (2013 in Edinburgh), it offers the vibrant German and international neutron community an opportunity to debate topical issues in a stimulating atmosphere. Originating from ''BMBF Verbundtreffen'' - meetings for projects funded by the German Federal Ministry of Education and Research - this conference series has a strong tradition of providing a forum for the discussion of collaborative research projects and future developments in the field of research with neutrons in general. Neutron scattering, by its very nature, is used as a powerful probe in many different disciplines and areas, from particle and condensed matter physics through to chemistry, biology, materials sciences, engineering sciences, right up to geology and cultural heritage; the German Neutron Scattering Conference thus provides a unique chance for exploring interdisciplinary research opportunities. It also serves as a showcase for recent method and instrument developments and to inform users of new advances at neutron facilities.

  20. The Behavior of Matter under Extreme Conditions

    NARCIS (Netherlands)

    Paerels, F.; Méndez, M.; Agueros, M.; Baring, M.; Barret, D.; Bhattacharyya, S.; Cackett, E.; Cottam, J.; Diaz Trigo, M.; Fox, D.; Garcia, M.; Gotthelf, E.; Hermsen, W.; Ho, W.; Hurley, K.; Jonker, P.; Juett, A.; Kaaret, P.; Kargaltsev, O.; Lattimer, J.; Matt, G.; Özel, F.; Pavlov, G.; Rutledge, R.; Smith, R.; Stella, L.; Strohmayer, T.; Tananbaum, H.; Uttley, P.; van Kerkwijk, M.; Weisskopf, M.; Zane, S.

    2009-01-01

    The cores of neutron stars harbor the highest matter densities known to occur in nature, up to several times the densities in atomic nuclei. Similarly, magnetic field strengths can exceed the strongest fields generated in terrestrial laboratories by ten orders of magnitude. Hyperon-dominated matter,

  1. HNC variational calculations of boson matter

    International Nuclear Information System (INIS)

    Lantto, L.J.; Jackson, A.D.; Siemens, P.J.

    1977-01-01

    A simple and reliable numerical technique is given for determining the two-body distribution function which minimizes the HNC energy of boson matter. Numerical results are presented for the neutron matter homework problem and the 4 He Lennard-Jones potential. The resulting distribution function is found to have proper asymptotic behaviour and yields reasonable binding energies. (Auth.)

  2. Neutron stars with kaon condensation in relativistic effective model

    International Nuclear Information System (INIS)

    Wu, Chen; Ma, Yugang; Qian, Weiliang; Yang, Jifeng

    2013-01-01

    Relativistic mean-field theory with parameter sets FSUGold and IU-FSU is extended to study the properties of neutron star matter in β equilibrium by including Kaon condensation. The mixed phase of normal baryons and Kaon condensation cannot exist in neutron star matter for the FSUGold model and the IU-FSU model. In addition, it is found that when the optical potential of the K - in normal nuclear matter U K ≳ -100 MeV, the Kaon condensation phase is absent in the inner cores of the neutron stars. (author)

  3. Renormalization group approach to superfluid neutron matter

    Energy Technology Data Exchange (ETDEWEB)

    Hebeler, K.

    2007-06-06

    In the present thesis superfluid many-fermion systems are investigated in the framework of the Renormalization Group (RG). Starting from an experimentally determined two-body interaction this scheme provides a microscopic approach to strongly correlated many-body systems at low temperatures. The fundamental objects under investigation are the two-point and the four-point vertex functions. We show that explicit results for simple separable interactions on BCS-level can be reproduced in the RG framework to high accuracy. Furthermore the RG approach can immediately be applied to general realistic interaction models. In particular, we show how the complexity of the many-body problem can be reduced systematically by combining different RG schemes. Apart from technical convenience the RG framework has conceptual advantage that correlations beyond the BCS level can be incorporated in the flow equations in a systematic way. In this case however the flow equations are no more explicit equations like at BCS level but instead a coupled set of implicit equations. We show on the basis of explicit calculations for the single-channel case the efficacy of an iterative approach to this system. The generalization of this strategy provides a promising strategy for a non-perturbative treatment of the coupled channel problem. By the coupling of the flow equations of the two-point and four-point vertex self-consistency on the one-body level is guaranteed at every cutoff scale. (orig.)

  4. Variational theory of nuclear and neutron matter

    International Nuclear Information System (INIS)

    Pandharipande, V.R.; Wiringa, R.B.

    1989-06-01

    In these lectures we will discuss attempts to solve the A = 3 to ∞ nuclear many-body problems with the variational method. We choose the form of a variational wave function Χ v (1, 2 hor-ellipsis A) to describe the ground state. The Χ v and the ground-state energy E v are obtained by minimizing E v = left-angle Χ v |H|Χ v right-angle/left-angle Χ v |Χ v right-angle with respect to variations in Χ v . If the form of the variational wave function is chosen properly we can expect Χ v ∼ Χ 0 and E v ∼ E 0 where Χ 0 and E 0 are the exact ground-state wave function and energy. In general E v ≥ E 0 in variational calculations. 63 refs., 11 figs

  5. Variational theory of nuclear and neutron matter

    Energy Technology Data Exchange (ETDEWEB)

    Pandharipande, V.R.; Wiringa, R.B. (Illinois Univ., Urbana, IL (USA). Dept. of Physics; Argonne National Lab., IL (USA))

    1989-06-01

    In these lectures we will discuss attempts to solve the A = 3 to {infinity} nuclear many-body problems with the variational method. We choose the form of a variational wave function {Chi}{sub v}(1, 2{hor ellipsis}A) to describe the ground state. The {Chi}{sub v} and the ground-state energy E{sub v} are obtained by minimizing E{sub v} = {l angle}{Chi}{sub v}{vert bar}H{vert bar}{Chi}{sub v}{r angle}/{l angle}{Chi}{sub v}{vert bar}{Chi}{sub v}{r angle} with respect to variations in {Chi}{sub v}. If the form of the variational wave function is chosen properly we can expect {Chi}{sub v} {approx} {Chi}{sub 0} and E{sub v} {approx} E{sub 0} where {Chi}{sub 0} and E{sub 0} are the exact ground-state wave function and energy. In general E{sub v} {ge} E{sub 0} in variational calculations. 63 refs., 11 figs.

  6. Isotope dilution mass spectrometry as the primary method of measurement for the amount of matter. Application to cadmium determination in biological materials and comparison with instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Munoz, Luis; Gras, Nuri; Quejido, Alberto; Ferrada, Carlos

    2001-01-01

    A primary method of measurement as defined by the Consultative Committee on the Quantity of Matter (Comite Consultatif pour la Quantite de Matiere, CCQM) of the International Bureau of Weights and Measurements (Bureau International des Poids et Mesures, BIPM), is one whose measurement process is perfectly known, has valid theoretical foundations and is fully described and answers to an equation that relates what is measured with what is intended to be measured without any significant empirical correction factors. It is also a method that has insignificant systematic errors, where only magnitudes from the International System of Units (SI) are used and where, preferably, the uncertainties are small ones. They are, therefore, procedures that do not need instrumental calibration. The absolute methods of measurement allow a chain of traceability to be formed between the result obtained and the magnitude of the SI assigned to what is measured. So the results are said to be traceable to the SI. One of the methods that meets these requirements and is recognized as the primary method by the CCQM is Isotope Dilution Mass Spectrometry (IDMS). Through a project of Technical Cooperation with the International Atomic Energy Agency in the area of Chemical Metrology, the CCHEN obtained training in CIEMAT, Spain, in IDMS and its applications to the analysis of biological samples. This work describes the first experience carried out entirely in Chilean laboratories, applying IDMS to the determination of cadmium in the biological reference materials Oyster Tissue 15566-A from the NIST, United States, Dogfish Liver, DOLT-2 from the NRC-CNRC, Canada and Poplar Leaves GBW07604 from the NRCC, China. The samples were traced with an isotope enriched spike 111 Cd and then shaken to obtain the isotopic exchange. Once dissolved, the isotopic relationship 111 Cd/ 114 Cd was determined in the samples using mass spectrometry with plasma source. These results were compared with those obtained

  7. Dark Matter

    Directory of Open Access Journals (Sweden)

    Einasto J.

    2011-06-01

    Full Text Available I give a review of the development of the concept of dark matter. The dark matter story passed through several stages from a minor observational puzzle to a major challenge for theory of elementary particles. Modern data suggest that dark matter is the dominant matter component in the Universe, and that it consists of some unknown non-baryonic particles. Dark matter is the dominant matter component in the Universe, thus properties of dark matter particles determine the structure of the cosmic web.

  8. Magnetic field devices for neutron spin transport and manipulation in precise neutron spin rotation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado-Velázquez, M. [Posgrado en Ciencias Físicas, Universidad Nacional Autónoma de México, 04510 (Mexico); Barrón-Palos, L., E-mail: libertad@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 (Mexico); Crawford, C. [University of Kentucky, Lexington, KY 40506 (United States); Snow, W.M. [Indiana University, Bloomington, IN 47405 (United States)

    2017-05-11

    The neutron spin is a critical degree of freedom for many precision measurements using low-energy neutrons. Fundamental symmetries and interactions can be studied using polarized neutrons. Parity-violation (PV) in the hadronic weak interaction and the search for exotic forces that depend on the relative spin and velocity, are two questions of fundamental physics that can be studied via the neutron spin rotations that arise from the interaction of polarized cold neutrons and unpolarized matter. The Neutron Spin Rotation (NSR) collaboration developed a neutron polarimeter, capable of determining neutron spin rotations of the order of 10{sup −7} rad per meter of traversed material. This paper describes two key components of the NSR apparatus, responsible for the transport and manipulation of the spin of the neutrons before and after the target region, which is surrounded by magnetic shielding and where residual magnetic fields need to be below 100 μG. These magnetic field devices, called input and output coils, provide the magnetic field for adiabatic transport of the neutron spin in the regions outside the magnetic shielding while producing a sharp nonadiabatic transition of the neutron spin when entering/exiting the low-magnetic-field region. In addition, the coils are self contained, forcing the return magnetic flux into a compact region of space to minimize fringe fields outside. The design of the input and output coils is based on the magnetic scalar potential method.

  9. Fundamental neutron physics at a 1 MW long pulse spallation neutron source

    International Nuclear Information System (INIS)

    Greene, G.L.

    1995-01-01

    Modern neutron sources and modern neutron science share a common origin in mid twentieth century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for the study of condensed matter with modern neutron sources being primarily used (and primarily justified) as tools for condensed matter research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities carried out at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high flux neutron facilities. Future sources, particularly high power spallation sources, offer exciting possibilities for the continuation of this program of research

  10. The weak conversion rate in quark matter

    International Nuclear Information System (INIS)

    Heiselberg, H.

    1992-01-01

    The weak conversion rate of strange to down quarks, s + u ↔ u + d, is calculated analytically for degenerate u, d and s quark matter to leading orders in temperature and deviations from chemical equilibrium. The rate is applied to burning of neutron matter into quark matter, to evaporation from quark nuggets in the early universe, for estimating the lifetime of strangelets, and to pulsar glitches

  11. Nondiffractive applications of neutrons at the spallation source SINQ

    International Nuclear Information System (INIS)

    Lehmann, E.

    1996-01-01

    The paper delivers an overview about experiments with neutrons from the spallation source SINQ which are not especially devoted to neutron scattering. A total of six experimental facilities are under construction using thermal as well as cold neutrons. Starting with some general considerations about the interaction of neutrons with matter, the principles, boundary conditions and the experimental set up of these experiments are described briefly. Some more details are given for the neutron radiography facility NEUTRA as the author's special interest and research field. (author) 7 figs., 2 tabs., 9 refs

  12. Nondiffractive applications of neutrons at the spallation source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    The paper delivers an overview about experiments with neutrons from the spallation source SINQ which are not especially devoted to neutron scattering. A total of six experimental facilities are under construction using thermal as well as cold neutrons. Starting with some general considerations about the interaction of neutrons with matter, the principles, boundary conditions and the experimental set up of these experiments are described briefly. Some more details are given for the neutron radiography facility NEUTRA as the author`s special interest and research field. (author) 7 figs., 2 tabs., 9 refs.

  13. neutron radiography

    International Nuclear Information System (INIS)

    Barton, J.P.

    1993-01-01

    Neutron radiography (or radiology) is a diverse filed that uses neutrons of various energies, subthermal, thermal, epithermal or fast in either steady state or pulsed mode to examine objects for industrial, medical, or other purposes, both microscopic and macroscopic. The applications include engineering design, biological studies, nondestructive inspection and materials evaluation. In the past decade, over 100 different centers in some 30 countries have published reports of pioneering activities using reactors, accelerators and isotopic neutron sources. While film transparency and electronic video are most common imaging methods for static or in motion objects respectively, there are other important data gathering techniques, including track etch, digital gauging and computed tomography. A survey of the world-wide progress shows the field to be gaining steadily in its diversity, its sophistication and its importance. (author)

  14. Production and applications of neutrons using particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Chichester, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2009-11-01

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  15. A pulsed neutron Ramsey's method

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Y. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan)]. E-mail: yasuhiro.masuda@kek.jp; Ino, T. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Jeong, S.C. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Muto, S. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Skoy, V. [Joint Institute for Nuclear Reasearch, 141980 Dubna (Russian Federation); Watanabe, Y. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan)

    2005-02-15

    A Ramsey's method with pulsed neutrons is proposed. A Ramsey signal, which is a neutron spin rotation about a static magnetic field for a time interval between two separated oscillatory fields, is observed as a function of a neutron time of flight (TOF) in this method. The neutron spin rotation or the RF oscillation is used as a clock of the neutron velocity measurement which ranges from cold to epithermal neutron energies. This method together with the TOF measurement can be used for neutron inelastic scattering experiments. In addition, this method can be applied to the measurement of magnetic and pseudomagnetic fields in matter, and also to neutron spin manipulation for spin dependent scattering.

  16. NEUTRONIC REACTOR

    Science.gov (United States)

    Wigner, E.P.; Weinberg, A.W.; Young, G.J.

    1958-04-15

    A nuclear reactor which uses uranium in the form of elongated tubes as fuel elements and liquid as a coolant is described. Elongated tubular uranium bodies are vertically disposed in an efficient neutron slowing agent, such as graphite, for example, to form a lattice structure which is disposed between upper and lower coolant tanks. Fluid coolant tubes extend through the uranium bodies and communicate with the upper and lower tanks and serve to convey the coolant through the uranium body. The reactor is also provided with means for circulating the cooling fluid through the coolant tanks and coolant tubes, suitable neutron and gnmma ray shields, and control means.

  17. Neutron dosimeter

    International Nuclear Information System (INIS)

    Bartko, J.; Schoch, K.F. Jr.; Congedo, T.V.; Anderson, S.L. Jr.

    1989-01-01

    This patent describes a nuclear reactor. It comprises a reactor core; a thermal shield surrounding the reactor core; a pressure vessel surrounding the thermal shield; a neutron dosimeter positioned outside of the thermal shield, the neutron dosimeter comprising a layer of fissile material and a second layer made of a material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose; and means, outside the pressure vessel and electrically connected to the layer of second material, for measuring electrical conductivity of the layer of second material

  18. Development of resonant detectors for epithermal neutron spectroscopy at pulsed neutron sources

    International Nuclear Information System (INIS)

    Tardocchi, M.; Pietropaolo, A.; Senesi, R.; Andreani, C.; Gorini, G.

    2004-01-01

    New perspectives for epithermal neutron spectroscopy are opened by the development of new detectors for inverse geometry time of flight spectrometers at pulsed neutron sources. One example is the Very Low Angle Detector (VLAD) bank planned to be delivered, within the next 4 years, within the eVERDI project, on the neutron spectrometer VESUVIO, at the ISIS pulsed neutron source (UK). VLAD will extend the (q,ω) kinematical region for neutron scattering to low wavefactor transfer (q -1 ) still keeping energy transfer >1 eV, thus allowing the investigations of new experimental studies in condensed matter systems. The technique being developed for detection of epithermal neutrons, within this low q and high-energy transfer region, is the Resonance Detection Technique. In this work, the state of the detector development will be presented with special focus on the results obtained with some prototype detectors, namely YAP scintillators and cadmium-zinc-telluride semiconductors

  19. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi; Oda, Masahiro; Takahashi, Kenji; Ohkubo, Kohei; Tasaka, Kanji; Tsuruno, Akira; Matsubayashi, Masahito.

    1993-01-01

    This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

  20. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  1. The technological development of neutron radiography

    International Nuclear Information System (INIS)

    Garrett, D.A.; Berger, H.

    1977-01-01

    Neutron radiography is a relatively recent technological development in the annals of non-destructive evaluation. It promises to play a role of increasing importance as the technology is further developed. The technique is placed in prospective with regard to other non-destructive evaluation methods in this paper. The history of the development of neutron radiography is traced to the early work of Becker, Bothe and the Joliot-Curies in Europe, and to the work of Chadwick in Great Britain. Details of the experiments which led to the discovery of the neutron by Chadwick in 1932, nuclear properties and energy classifications of neutrons, and the various interactions of neutrons with matter are discussed in detail. A history of neutron radiography is presented which outlines the early experiments by Kallmann and Kuhn; these experiments led to the production of the first neutron radiograph in Germany in 1938. The paper continues with a description of the general techniques that are characteristic of the neutron radiographic process. The breadth and extent of present neutron radiographic technology is discussed as a conclusion of the paper. (author)

  2. Exotic phases in neutron stars

    International Nuclear Information System (INIS)

    Li, A.; Burgio, G.F.; Lombardo, U.; Peng, G.X.

    2008-01-01

    The appearance of exotic phases in neutron stars is studied. The possible transition from hadron to quark phase is studied within the density dependent mass quark model, and the kaon condensation within the Nelson and Kaplan model. In both cases a microscopic approach is adopted for dense hadron matter. From the study of the possible coexistence between the two phases it is found that the hybrid phase may strongly hinder the onset of kaon condensation. (author)

  3. Neutron spectroscopy at the turn of the century

    CERN Document Server

    Popov, Yu P

    2003-01-01

    Neutron spectrometry is a powerful method of investigating atomic nuclei and condensed matter. Such investigations provide necessary data for a very wide spectrum of scientific and technological applications from the fundamental problems of the structure of matter and nucleosynthesis in the Universe to atomic power technologies and the structure of condensed matter. The most frequently utilized is the time-of-flight (TOF) method for powerful pulsed neutron sources. However, in many cases, one can use more effective, simpler and cheaper methods. For example, for astrophysics and radioactive waste transmutation problems, it is sufficient to know an average resonance cross section or "resonance integrals" for capture and fission reactions for neutron spectra specific to neutron fluxes in stars or in the active zone of a transmutation reactor. In these cases, the slow-down neutron spectroscopy (SDNS) methods in lead and graphite moderators will be useful. Compared to the TOF method, the lead SDNS gives a 10/sup 3...

  4. Preliminary examination of the applicability of imaging plates to fast neutron radiography

    International Nuclear Information System (INIS)

    Matsubayashi, Masahito; Hibiki, Takashi; Mishima, Kaichiro; Yoshii, Koji; Okamoto, Koji

    2001-01-01

    Fast neutron radiography is an attractive non-destructive inspection technique because of the excellent penetration characteristics of fast neutrons in matter. However, the difficulty of detecting fast neutrons reduces this attractive feature. As an experiment to overcome the difficulty, imaging plates were applied to fast neutron radiography. A simple combination of two sheets of imaging plates and a sheet of polyethylene as a proton emitter was examined with the (fast neutron, thermal neutron and gamma ray) FTG discriminator proposed by Yoneda et al. . The experimental results showed that the method could be applicable to fast neutron radiography with effective discrimination of γ-rays

  5. Polarized neutron scattering research: the beginning

    International Nuclear Information System (INIS)

    Mezei, F.

    2005-01-01

    The visionary idea of using neutron scattering for the study of magnetic phenomena in condensed matter was proposed by Bloch in 1936, mere 4 years after the neutron was discovered. It was based on one of the surprises the neutron presented the scientific community with: it is neutral, yet it has a magnetic moment, which latter was then not yet directly observed though. Although the first results proved to be mathematically wrong, due to a non-trivial ambiguity of classical electromagnetism theory, which could only be settled by neutron beam experiments 15 years later, the recognition lead to the advent of a most productive area of modern research, which culminated in the development of the powerful and sophisticated techniques of polarized neutron scattering. This recollection traces the early milestones of the development of the field in strong interaction between theory and experiment

  6. Solid Matter

    CERN Document Server

    Angelo, Joseph A

    2011-01-01

    Supported by a generous quantity of full-color illustrations and interesting sidebars, Solid Matter introduces the basic characteristics and properties of solid matter. It briefly describes the cosmic connection of the elements, leading readers through several key events in human pre-history that resulted in more advanced uses of matter in the solid state. Chapters include:. -Solid Matter: An Initial Perspective. -Physical Behavior of Matter. -The Gravity of Matter. -Fundamentals of Materials Science. -Rocks and Minerals. -Metals. -Building Materials. -Carbon Earth's Most Versatile Element. -S

  7. 40 years of neutron physics in Dubna

    International Nuclear Information System (INIS)

    Aksenov, V.L.

    2000-01-01

    This publication is based on the report presented by the author at the jubilee meeting of the 88th session of the Scientific Council of the Joint Institute for Nuclear Research (JINR) on June 8, 2000 devoted to the 40th anniversary of neutron investigations in Dubna. JINR is one of the world leading scientific centers in the use of neutrons for the investigation of fundamental interactions and symmetries, the structure of atomic nuclei, and the condensed state of matter. Scientists from 30 countries conduct experiments at the JINR neutron sources

  8. Accelerators for condensed matter research

    International Nuclear Information System (INIS)

    Williams, P.R.

    1990-01-01

    The requirement for high energy, high luminosity beams has stimulated the science and engineering of accelerators to a point where they open up opportunities for new areas of scientific application to benefit from the advances driven by particle physics. One area of great importance is the use of electron or positron storage rings as a source of intense VUV or X-ray synchrotron radiation. An accelerator application that has grown in prominence over the last 10 years has been spallation neutron sources. Neutrons offer an advantage over X-rays as a condensed matter probe because the neutron energy is usually of the same order as the room temperature thermal energy fluctuations in the sample being studied. Another area in which accelerators are playing an increasingly important role in condensed matter research concerns the use of Mu mesons, Muons, as a probe. This paper also presents a description of the ISIS Spallation Neutron Source. The design and status of the facility are described, and examples are given of its application to the study of condensed matter. (N.K.)

  9. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

    The method of operating a water-cooled neutronic reactor having a graphite moderator is described which comprises flowing a gaseous mixture of carbon dioxide and helium, in which the helium comprises 40--60 volume percent of the mixture, in contact with the graphite moderator. 2 claims, 4 figures

  10. Progress report on neutron scattering at JAERI

    Energy Technology Data Exchange (ETDEWEB)

    Morii, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-10-01

    In the first half of fiscal year 1997, JRR-3M was operated for 97 days followed by a long term shut down for its annual maintenance. Three days were lost out of 100 scheduled operation days, due to a trouble in irradiation facility. Neutron scattering research activities at the JRR-3M have been extended from that of fiscal year 1996. In the Research Group for Quantum Condensed Matter System, experimental study under high pressures, low temperatures and high fields as well as coupling of these conditions were planned to find new quantum condensed matter systems. And, obtained experimental results were immediately provided to theorists for their investigations. In cooperation with new group, Research Group for Neutron Scattering of Strongly Correlated Electron Systems and Research Group for Neutron Scattering at Ultralow Temperatures were carrying neutron scattering experiments at JRR-3M. Research Group for Neutron Crystallography in Biology had opened a way for investigating biomatter neutron diffraction research with high experimental accuracy by growing a millimeter-class large single crystal. In fiscal year 1997, 39 research projects were conducted by these four groups and other staffs in JAERI, 27 projects collaborated with university researchers and 3 projects collaborated with private enterprises were also conducted as complementary researches. 2117 days of machine times were requested to use 8 neutron scattering instruments this year, which corresponded to 1.51 times larger than those planned at its beginning. (G.K.)

  11. Sequía inminente de neutrones en Europa

    CERN Multimedia

    Ruiz de Elvira, Malen

    2002-01-01

    Four regions hope for the new European installation of spallation, waiting for a political decision. Europe cannot lose its actual and great supremacy in the field of researches using neutrons to illuminate the matter and find its secrets

  12. Revisiting Field Burial by Accretion onto Neutron Stars

    Indian Academy of Sciences (India)

    Dipanjan Mukherjee

    2017-09-12

    Sep 12, 2017 ... review the recent work on magnetic confinement of accreted matter on neutron stars poles. We present ..... hours to days, see Brown & Bildsten 1998) where the ...... Radhakrishnan, V., Srinivasan, G. 1984, in: Second Asian-.

  13. Radiography and tomography with polarized neutrons

    International Nuclear Information System (INIS)

    Treimer, Wolfgang

    2014-01-01

    Neutron imaging became important when, besides providing impressive radiographic and tomographic images of various objects, physical, quantification of chemical, morphological or other parameters could be derived from 2D or 3D images. The spatial resolution of approximately 50 µm (and less) yields real space images of the bulk of specimens with more than some cm 3 in volume. Thus the physics or chemistry of structures in a sample can be compared with scattering functions obtained e.g. from neutron scattering. The advantages of using neutrons become more pronounced when the neutron spin comes into play. The interaction of neutrons with magnetism is unique due to their low attenuation by matter and because their spin is sensitive to magnetic fields. Magnetic fields, domains and quantum effects such as the Meissner effect and flux trapping can only be visualized and quantified in the bulk of matter by imaging with polarized neutrons. This additional experimental tool is gaining more and more importance. There is a large number of new fields that can be investigated by neutron imaging, not only in physics, but also in geology, archeology, cultural heritage, soil culture, applied material research, magnetism, etc. One of the top applications of polarized neutron imaging is the large field of superconductivity where the Meissner effect and flux pinning can be visualized and quantified. Here we will give a short summary of the results achieved by radiography and tomography with polarized neutrons. - Highlights: • Radiography and tomography with polarized neutrons yield new results concerning the suppressed Meissner effect and magnetic flux trapping. • Suppressed Meissner effect was observed in pure lead samples and niobium. • Trapped magnetic fields in cylindrical Pb samples are squeezed around the rod axis. • The shape and the amount of trapped fields could be determined and quantified

  14. Radiography and tomography with polarized neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Treimer, Wolfgang, E-mail: treimer@helmholtz-berlin.de [University of Applied Sciences, Beuth Hochschule für Technik Berlin, Department Mathematics Physics and Chemistry, Luxemburgerstr. 10, D-13353 Berlin (Germany); Helmholtz Zentrum für Materialien und Energie, Department G – GTOMO, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany)

    2014-01-15

    Neutron imaging became important when, besides providing impressive radiographic and tomographic images of various objects, physical, quantification of chemical, morphological or other parameters could be derived from 2D or 3D images. The spatial resolution of approximately 50 µm (and less) yields real space images of the bulk of specimens with more than some cm{sup 3} in volume. Thus the physics or chemistry of structures in a sample can be compared with scattering functions obtained e.g. from neutron scattering. The advantages of using neutrons become more pronounced when the neutron spin comes into play. The interaction of neutrons with magnetism is unique due to their low attenuation by matter and because their spin is sensitive to magnetic fields. Magnetic fields, domains and quantum effects such as the Meissner effect and flux trapping can only be visualized and quantified in the bulk of matter by imaging with polarized neutrons. This additional experimental tool is gaining more and more importance. There is a large number of new fields that can be investigated by neutron imaging, not only in physics, but also in geology, archeology, cultural heritage, soil culture, applied material research, magnetism, etc. One of the top applications of polarized neutron imaging is the large field of superconductivity where the Meissner effect and flux pinning can be visualized and quantified. Here we will give a short summary of the results achieved by radiography and tomography with polarized neutrons. - Highlights: • Radiography and tomography with polarized neutrons yield new results concerning the suppressed Meissner effect and magnetic flux trapping. • Suppressed Meissner effect was observed in pure lead samples and niobium. • Trapped magnetic fields in cylindrical Pb samples are squeezed around the rod axis. • The shape and the amount of trapped fields could be determined and quantified.

  15. Methods for absorbing neutrons

    Science.gov (United States)

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  16. Cool quark matter

    CERN Document Server

    Kurkela, Aleksi

    2016-07-20

    We generalize the state-of-the-art perturbative Equation of State of cold quark matter to nonzero temperatures, needed in the description of neutron star mergers and core collapse processes. The new result is accurate to order g^5 in the gauge coupling, and is based on a novel framework for dealing with the infrared sensitive soft field modes of the theory. The zero Matsubara mode sector is treated using a dimensionally reduced effective theory, while the soft non-zero modes are resummed using the Hard Thermal Loop approximation. This combination of known effective descriptions offers unprecedented access to small but nonzero temperatures, both in and out of beta equilibrium.

  17. Ultimate energy density of observable cold baryonic matter.

    Science.gov (United States)

    Lattimer, James M; Prakash, Madappa

    2005-03-25

    We demonstrate that the largest measured mass of a neutron star establishes an upper bound to the energy density of observable cold baryonic matter. An equation of state-independent expression satisfied by both normal neutron stars and self-bound quark matter stars is derived for the largest energy density of matter inside stars as a function of their masses. The largest observed mass sets the lowest upper limit to the density. Implications from existing and future neutron star mass measurements are discussed.

  18. Basic research for developing the quantitative neutron radiography

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi; Ikeda, Yasushi; Ohkubo, Kohei; Tasaka, Kanji; Yoneda, Kenji; Fujine, Shigenori.

    1992-01-01

    This investigation concerns the basic research and development on quantitative neutron radiography by using a honeycomb collimator which reduces the effect due to scattered neutrons in objective matter. On the observation of the hydrogenate materials such as metal hydrides, water and hydrocarbons by neutron radiography, scattered neutrons from these objectives make the quantitativeness of the neutron radiographic image lower grade. In order to improve the quantitativeness of the image, a honeycomb collimator, which is a honeycomb structure of neutron absorbing material, was introduced to the conventional neutron radiography system. By setting the neutron-absorbing honeycomb collimator between objective and imaging system, neutrons scattered in the objective were absorbed by the honeycomb material and attenuated before coming to the imaging system, but neutrons which were transmitted the objective sample without any interaction reached the imaging system and formed the image of the sample. As the image by purely transmitted neutrons is intrinsic due to the neutronic character of the sample, the image data give the quantitative information. In the present experiment, aluminum honeycomb which was coated with boron nitride was prepared and used in order to image the standard stepwise samples for the evaluation of the quantitative grade of the newly proposed neutron radiography method. From the comparison between macroscopic total cross section and the attenuation coefficient of the thermal neutron for aluminum, copper and hydrocarbons, it was confirmed that they were fairly consistent each other. It can be concluded that the newly proposed neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improves remarkably the quantitativeness of the neutron radiography technique. (author)

  19. Speech Matters

    DEFF Research Database (Denmark)

    Hasse Jørgensen, Stina

    2011-01-01

    About Speech Matters - Katarina Gregos, the Greek curator's exhibition at the Danish Pavillion, the Venice Biannual 2011.......About Speech Matters - Katarina Gregos, the Greek curator's exhibition at the Danish Pavillion, the Venice Biannual 2011....

  20. Memory Matters

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Memory Matters KidsHealth / For Kids / Memory Matters What's in ... of your complex and multitalented brain. What Is Memory? When an event happens, when you learn something, ...

  1. Basic of Neutron NDA

    Energy Technology Data Exchange (ETDEWEB)

    Trahan, Alexis Chanel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-15

    The objectives of this presentation are to introduce the basic physics of neutron production, interactions and detection; identify the processes that generate neutrons; explain the most common neutron mechanism, spontaneous and induced fission and (a,n) reactions; describe the properties of neutron from different sources; recognize advantages of neutron measurements techniques; recognize common neutrons interactions; explain neutron cross section measurements; describe the fundamental of 3He detector function and designs; and differentiate between passive and active assay techniques.

  2. Applications of neutron scattering to the study of magnetic materials

    International Nuclear Information System (INIS)

    Koehler, W.C.

    1976-01-01

    The types of interactions that neutrons undergo with condensed matter are reviewed and those properties of neutrons that make them an ideal probe for the study of magnetism on a microscopic scale are discussed. Following a very brief survey of experimental methods, a few illustrative examples of specific investigations are described in sufficient detail to illustrate the power of the techniques. Views as to the future directions that may be taken by neutron scattering are presented

  3. Role of strangeness to the neutron star mass and cooling

    Science.gov (United States)

    Lee, Chang-Hwan; Lim, Yeunhwan; Hyun, Chang Ho; Kwak, Kyujin

    2018-01-01

    Neutron star provides unique environments for the investigation of the physics of extreme dense matter beyond normal nuclear saturation density. In such high density environments, hadrons with strange quarks are expected to play very important role in stabilizing the system. Kaons and hyperons are the lowest mass states with strangeness among meson and bayron families, respectively. In this work, we investigate the role of kaons and hyperons to the neutron star mass, and discuss their role in the neutron star cooling.

  4. Phase transitions in dense matter

    Science.gov (United States)

    Dexheimer, Veronica; Hempel, Matthias; Iosilevskiy, Igor; Schramm, Stefan

    2017-11-01

    As the density of matter increases, atomic nuclei disintegrate into nucleons and, eventually, the nucleons themselves disintegrate into quarks. The phase transitions (PT's) between these phases can vary from steep first order to smooth crossovers, depending on certain conditions. First-order PT's with more than one globally conserved charge, so-called non-congruent PT's, have characteristic differences compared to congruent PT's. In this conference proceeding we discuss the non-congruence of the quark deconfinement PT at high densities and/or temperatures relevant for heavy-ion collisions, neutron stars, proto-neutron stars, supernova explosions, and compact-star mergers.

  5. Hadron physics and the structure of neutron stars

    International Nuclear Information System (INIS)

    Kutschera, M.

    1996-09-01

    The equation of state of hadronic matter in neutron stars is briefly reviewed. Uncertainties regarding the stiffness and composition of hadronic matter are discussed. Importance of poorly known short range interactions of nucleons and hyperons is emphasized. Condensation of meson fields and the role of subhadronic degrees of freedom is considered. Empirical constraints on the equation of state emerging from observations of neutron stars are discussed. The nature of the remnant of SN1987A is considered. (author)

  6. The research of condensed matter physics by using intense proton accelerator

    International Nuclear Information System (INIS)

    Endoh, Yasuo

    1990-01-01

    The present article covers the application of intense protons to basic condensed matter physics. Major recent neutron scattering activities in condensed matter physics are first outlined, emphasizing the fact that the contribution of accelerator base science has a tremendous impact on this basic science. Application of spallation neutrons to condensed matter physics is discussed in relation to such subjects as high energy (epithermal) excitations and small angle neutron scattering. Then the specific subject of high Tc superconductor is addressed, focusing on how neutrons as well as muons provide experimental results that serve significantly in exploring the mechanism of exotic high Tc superconductivity. Techniques for neutron polarization must be developed in the future. The neutron spin reflectivity ratio has been shown to be a sensitive probe of surface depth profile of magnetization. Another new method is neutron depolarization to probe bulk magnetic induction throughout a slab which neutrons pass through. (N.K.)

  7. Neutron physics and the theory of liquids 1956-1976

    International Nuclear Information System (INIS)

    Schofield, P.

    1980-01-01

    A review is given of work carried out in the Theoretical Division, Harwell from 1956-1976 on neutron thermalization and scattering, resulting from different fuel composition and temperatures within nuclear reactor cores, and the use of thermal neutron scattering as a probe of the structure and dynamics of condensed matter. (UK)

  8. Relativistic Processes and the Internal Structure of Neutron Stars

    International Nuclear Information System (INIS)

    Alvarez-Castillo, D. E.; Kubis, S.

    2011-01-01

    Models for the internal composition of Dense Compact Stars are reviewed as well as macroscopic properties derived by observations of relativistic processes. Modeling of pure neutron matter Neutron Stars is presented and crust properties are studied by means of a two fluid model.

  9. Energy-dispersive study of the interaction of fast neutrons with matter. Common final report of the DFG projects GR 1674/2 and FR 575/5 together with the institute for nuclear and particle physics, technical university Dresden; Energiedispersive Untersuchung der Wechselwirkung schneller Neutronen mit Materie. Gemeinsamer Abschlussbericht der DFG Projekte GR 1674/2 und FR 575/5, zusammen mit dem Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden

    Energy Technology Data Exchange (ETDEWEB)

    Altstadt, E.; Beckert, C. [Forschungszentrum Rossendorf e.V. (FZR) (Germany). Inst. fuer Sicherheitsforschung; Beyer, R. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (DE). Inst. fuer Kern- und Hadronenphysik] [and others

    2005-04-01

    In this final report on the research project ''Energy-dispersive study of the interaction of fast neutrons with matter, especially materials for fusion and materials from fission reactors the status reached after three years promotion is described. The aim of this project is the construction and first usage of a very complex time-of-flight system for the study of the interaction of fast neutrons with construction materials for fusion and fission reactors as well as with long-lived radioisotopes. Furthermore astrophysically relevant experiments on problems of the element synthesis shall be performed. The whole project is devided into two sections: 1. Development, construction and test of a pulsed photoneutron source at the ELBE accelerator of the FZ Rossendorf, 2. Application of the photoneutron sources for measurements of cross sections induced by fast, energy-selected neutrons.

  10. Dark Matter

    Indian Academy of Sciences (India)

    What You See Ain't What. You Got, Resonance, Vol.4,. No.9,1999. Dark Matter. 2. Dark Matter in the Universe. Bikram Phookun and Biman Nath. In Part 11 of this article we learnt that there are compelling evidences from dynamics of spiral galaxies, like our own, that there must be non-luminous matter in them. In this.

  11. Hyperon-mixed neutron stars

    International Nuclear Information System (INIS)

    Takatsuka, Tatsuyuki

    2004-01-01

    Hyperon mixing in neutron star matter is investigated by the G-matrix-based effective interaction approach under the attention to use the YN and the YY potentials compatible with hypernuclear data and is shown to occur at densities relevant to neutron star cores, together with discussions to clarify the mechanism of hyperon contamination. It is remarked that developed Y-mixed phase causes a dramatic softening of the neutron star equation of state and leads to the serious problem that the resulting maximum mass M max for neutron star model contradicts the observed neutron star mass (M max obs = 1.44 M Θ ), suggesting the necessity of some extra repulsion'' in hypernuclear system. It is shown that the introduction of three-body repulsion similar to that in nuclear system can resolve the serious situation and under the consistency with observation (M max > M obs ) the threshold densities for Λ and Σ - are pushed to higher density side, from 2ρ 0 to ∼ 4ρ 0 (ρ 0 being the nuclear density). On the basis of a realistic Y-mixed neutron star model, occurrence of Y-superfluidity essential for ''hyperon cooling'' scenario is studied and both of Λ- and Σ - -superfluids are shown to be realized with their critical temperatures 10 8-9 K, meaning that the hyperon cooling'' is a promising candidate for a fast non-standard cooling demanded for some neutron stars with low surface temperature. A comment is given as to the consequence of less attractive ΛΛ interaction suggested by the ''NAGARA event'' ΛΛ 6 He. (author)

  12. A matter of quarks

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Quarks are understood to interact through the 'colour' force, carried by gluons. Under normal conditions these quarks are confined - frozen together in 'colourless' states such as protons, neutrons and other strongly interacting particles. However if the quarks are compressed tightly together and/or are 'heated' by increasing their energy, they should eventually break loose from their colour bonds to form a new kind of matter – the so-called quark-gluon plasma. Although QGP has not yet been synthesized in the Laboratory, it was most likely the stuff of the Universe 10 -5 second after the Big Bang. Thus the search for this 'new' matter is attracting a growing number of physicists, theorists and experimenters from both the particle physics and nuclear physics fields

  13. Hyperons in dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Dapo, Haris

    2009-01-28

    The hyperon-nucleon YN low momentum effective interaction (V{sub low} {sub k}) allows for an extensive study of the behavior of hyperons in dense matter, together with an investigation of effects of the presence of hyperons on dense matter. The first step towards this goal is the construction of the matrix elements for the hyperon-nucleon low momentum potential. In order to assess the different properties of hyperons within these potentials we calculate the hyperon single-particle potentials in the Hartree-Fock approximation for all of the interactions. Their dependence on both momentum and density, is studied. The single-particle potentials are then used to determine the chemical potential of hyperons in neutron stars. For nucleonic properties, the nucleon-nucleon V{sub low} {sub k} can be used with the caveat that the calculation of the ground-state energy of symmetric nuclear matter does not correctly reproduce the properties of matter at saturation. With the nucleon-nucleon V{sub low} {sub k} one is unable to reach the densities needed for the calculation of neutron star masses. To circumvent this problem we use two approaches: in the first one, we parametrize the entire nucleonic sector. In the second one, we replace only the three-body force. The former will enable us to study neutron star masses, and the latter for studying the medium's response to the external probe. In this thesis we take the external probe to be the neutrino. By combining this parametrization with the YN V{sub low} {sub k} potential, we calculate the equation of state of equilibrated matter. Performing the calculation in the Hartree-Fock approximation at zero temperature, the concentrations of all particles are calculated. From these we can ascertain at which densities hyperons appear for a wide range of parameters. Finally, we calculate the masses of neutron stars with these concentrations. For the calculation of the medium's response to an external probe, we replace the three

  14. Hyperons in dense matter

    International Nuclear Information System (INIS)

    Dapo, Haris

    2009-01-01

    The hyperon-nucleon YN low momentum effective interaction (V low k ) allows for an extensive study of the behavior of hyperons in dense matter, together with an investigation of effects of the presence of hyperons on dense matter. The first step towards this goal is the construction of the matrix elements for the hyperon-nucleon low momentum potential. In order to assess the different properties of hyperons within these potentials we calculate the hyperon single-particle potentials in the Hartree-Fock approximation for all of the interactions. Their dependence on both momentum and density, is studied. The single-particle potentials are then used to determine the chemical potential of hyperons in neutron stars. For nucleonic properties, the nucleon-nucleon V low k can be used with the caveat that the calculation of the ground-state energy of symmetric nuclear matter does not correctly reproduce the properties of matter at saturation. With the nucleon-nucleon V low k one is unable to reach the densities needed for the calculation of neutron star masses. To circumvent this problem we use two approaches: in the first one, we parametrize the entire nucleonic sector. In the second one, we replace only the three-body force. The former will enable us to study neutron star masses, and the latter for studying the medium's response to the external probe. In this thesis we take the external probe to be the neutrino. By combining this parametrization with the YN V low k potential, we calculate the equation of state of equilibrated matter. Performing the calculation in the Hartree-Fock approximation at zero temperature, the concentrations of all particles are calculated. From these we can ascertain at which densities hyperons appear for a wide range of parameters. Finally, we calculate the masses of neutron stars with these concentrations. For the calculation of the medium's response to an external probe, we replace the three-body force with a density-dependent interaction. This

  15. Comprehensive asymmetric dark matter model

    Science.gov (United States)

    Lonsdale, Stephen J.; Volkas, Raymond R.

    2018-05-01

    Asymmetric dark matter (ADM) is motivated by the similar cosmological mass densities measured for ordinary and dark matter. We present a comprehensive theory for ADM that addresses the mass density similarity, going beyond the usual ADM explanations of similar number densities. It features an explicit matter-antimatter asymmetry generation mechanism, has one fully worked out thermal history and suggestions for other possibilities, and meets all phenomenological, cosmological and astrophysical constraints. Importantly, it incorporates a deep reason for why the dark matter mass scale is related to the proton mass, a key consideration in ADM models. Our starting point is the idea of mirror matter, which offers an explanation for dark matter by duplicating the standard model with a dark sector related by a Z2 parity symmetry. However, the dark sector need not manifest as a symmetric copy of the standard model in the present day. By utilizing the mechanism of "asymmetric symmetry breaking" with two Higgs doublets in each sector, we develop a model of ADM where the mirror symmetry is spontaneously broken, leading to an electroweak scale in the dark sector that is significantly larger than that of the visible sector. The weak sensitivity of the ordinary and dark QCD confinement scales to their respective electroweak scales leads to the necessary connection between the dark matter and proton masses. The dark matter is composed of either dark neutrons or a mixture of dark neutrons and metastable dark hydrogen atoms. Lepton asymmetries are generated by the C P -violating decays of heavy Majorana neutrinos in both sectors. These are then converted by sphaleron processes to produce the observed ratio of visible to dark matter in the universe. The dynamics responsible for the kinetic decoupling of the two sectors emerges as an important issue that we only partially solve.

  16. Characteristics of neutron irradiation facility and dose estimation method for neutron capture therapy at Kyoto University research reactor institute

    International Nuclear Information System (INIS)

    Kobayashi, T.; Sakurai, Y.; Kanda, K.

    2001-01-01

    The neutron irradiation characteristics of the Heavy Water Neutron Irradiation Facility (HWNIF) at the Kyoto University Research Reactor Institute (KIJRRI) for boron neutron capture therapy (BNCT), is described. The present method of dose measurement and its evaluation at the KURRI, is explained. Especially, the special feature and noticeable matters were expounded for the BNCT with craniotomy, which has been applied at present only in Japan. (author)

  17. Neutronic measurements of radioactive waste; Les mesures neutroniques des dechets radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Perot, B

    1997-12-31

    This document presents the general matters involved in the radioactive waste management and the different non destructive assays of radioactivity. The neutronic measurements used in the characterization of waste drums containing emitters are described with more details, especially the active neutronic interrogation assays with prompt or delayed neutron detection: physical principle, signal processing and evaluation of the detection limit. (author).

  18. A two-solar-mass neutron star measured using Shapiro delay

    NARCIS (Netherlands)

    Demorest, P.B.; Pennucci, T.; Ransom, S.M.; Roberts, M.S.E.; Hessels, J.W.T.

    2010-01-01

    Neutron stars are composed of the densest form of matter known to exist in our Universe, the composition and properties of which are still theoretically uncertain. Measurements of the masses or radii of these objects can strongly constrain the neutron star matter equation of state and rule out

  19. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2013-01-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, nanostructures investigated by small-angle neutron scattering, structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic neutron scattering, strongly correlated electrons, polymer dynamics, applications of neutron scattering. (HSI)

  20. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2012-01-01

    The following topics are dealt with: Neutron scattering in contemporary research, neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  1. Pulsed neutron generator

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Bykovskii, Yu.A.; Vergun, I.I.; Kozlovskii, K.I.; Kozyrev, Yu.P.; Leonov, R.K.; Simagin, B.I.; Tsybin, A.S.; Shikanov, A.Ie.

    1986-03-01

    The paper describes a new device for generating pulsed neutron fields, utilized in nuclear geophysics for carrying out pulsed neutron logging and activation analysis under field conditions. The invention employs a sealed-off neutron tube with a laser ion source which increases neutron yield to the level of 10 neutrons per second or higher. 2 refs., 1 fig

  2. Neutron scattering

    International Nuclear Information System (INIS)

    1991-02-01

    The annual report on hand gives an overview of the research work carried out in the Laboratory for Neutron Scattering (LNS) of the ETH Zuerich in 1990. Using the method of neutron scattering, it is possible to examine in detail the static and dynamic properties of the condensed material. In accordance with the multidisciplined character of the method, the LNS has for years maintained a system of intensive co-operation with numerous institutes in the areas of biology, chemistry, solid-state physics, crystallography and materials research. In 1990 over 100 scientists from more than 40 research groups both at home and abroad took part in the experiments. It was again a pleasure to see the number of graduate students present, who were studying for a doctorate and who could be introduced into the neutron scattering during their stay at the LNS and thus were in the position to touch on central ways of looking at a problem in their dissertation using this modern experimental method of solid-state research. In addition to the numerous and interesting ways of formulating the questions to explain the structure, nowadays the scientific programme increasingly includes particularly topical studies in connection with high temperature-supraconductors and materials research

  3. Neutron radiotherapy

    International Nuclear Information System (INIS)

    Thomas, F.J.

    1987-01-01

    The rationale for the application of neutron radiation for the treatment of malignancies is well established based on radiobiological studies. These factors include the presence of tissue hypoxia, radiation response as a function of cell cycle kinetics, the repair capacity of the malignant cells and the regeneration of malignant cells during a fractionated course of radiation. Despite the constraints under which the clinical trials to date have been conducted, promising results have been obtained. Randomized trials have demonstrated that neutron therapy is the treatment of choice for inoperable salivary gland carcinomas. A randomized trial of the RTOG has demonstrated a probable advantage for neutron radiation in the treatment of advanced prostate carcinomas but is yet to be confirmed. An improvement in local control has also been observed for selected sarcomas. Equivocal or contradictory results have been obtained for squamous cell carcinomas of the head and neck, bronchogenic carcinomas, advanced rectal, transitional cell carcinomas of the bladder and cervical carcinomas. The practical consequences of these radiobiological and clinical observations on the current generation of clinical trials is discussed

  4. Neutron star structure: Theory, observation, and speculation

    International Nuclear Information System (INIS)

    Pandharipande, V.R.; Pines, D.; Smith, R.A.

    1976-01-01

    The broad physical aspects of the neutron-neutron interaction in dense matter are reviewed, and an examination is made of the extent to which the equation of state of neutron star matter is influenced by phase transitions which have been proposed for the high-density regime. The dependence of the maximum neutron star mass and the stellar structure on the neutron-neutron interaction is studied through calculations of the equation of state of neutron matter based on four different models for this interaction: the Reid (R) and Bethe-Johnson (BJ) models, a tensor-interaction (TI) model which assumes that the attraction between nucleons comes from the higher order contribution of the pion-exchange tensor interaction, and a mean field (MF) model which assumes that all the attraction between nucleons is due to the exchange of an effective scalar meson. It is shown that the harder equations of state which result from the BJ, TI, and MF models give rise to significant modifications in the structure of neutron stars; heavy neutron stars (approximately-greater-than1 M/sub sun/) have both larger radii and thicker crusts than were predicted using the R model.These stars are used as a basis for comparing theory with observation for the mass and structure of neutron stars such as the Crab and Vela pulsars, and the compact X-ray sources Her X-1 and Vela X-1. We find that both theory and observation tend to favor an equation of state that is stiff in the region of 10 14 --10 15 g cm -3 and that a neutron star such as Her X-1 (Mapprox.1.3 M/sub sun/) has a radius of the order of 15 km with a crust thickness of order 5 km. Based on starquake theory, it is concluded that the Crab pulsar could have a mass as large as 1.3 M/sub sun/, with a critical strain angle approx.10 -3 , comparable to that suggested for Her X-1. The possibility of solid-core neutron stars and some of their observational consequences is discussed

  5. The dark side of matter

    International Nuclear Information System (INIS)

    Cline, D.

    2003-01-01

    The number of baryons (protons and neutrons) of the universe can be deduced from the relative abundances of light elements (deuterium, helium and lithium) that were generated during the very first minutes of the cosmic history. This calculation has shown that the baryonic matter represents only 5% of the total mass of the universe. As for neutrinos (hot dark matter), their very low mass restraints their contribution to only 0,3%. The spinning movement of galaxies requires the existence of huge quantity of matter that seems invisible (black matter). Astrophysicists have recently discovered that the universal expansion is accelerating and that the space geometry is euclidean, from these 2 facts they have deduced a value of the mass-energy density that implies the existence of something different from dark matter called dark energy and that is expected to represent about 70% of the mass of the universe. Physicists face the challenge of detecting black matter and black energy. The first attempt for detecting black matter began in 1997 when the UKDMC detector entered into service. Now more than half a dozen of detectors are searching for dark matter but till now in vain. A new generation of detectors (CDMS-2, ZEPLIN-2, CRESST-2 and Edelweiss-2) combining detection, new methods of particle discrimination and the study of the evolution of the signal over very long periods of time are progressively entering into operation. (A.C.)

  6. Quark Condensate in the Strange Matter

    Institute of Scientific and Technical Information of China (English)

    LU Chang-Fang; LU" Xiao-Fu

    2003-01-01

    In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including N, Σ, Ξ, and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The results show that the chiral symmetry is restored partially when the strange matter density increases and that 〈π→2〉 plays a very important role in the strange matter which may approach the constituents of the neutron stars. In addition, we can find that the strange matter density where the π-condensate emerges leads to the ratio of the nucleon number to baryon number.

  7. Quark matter in astrophysics and cosmology

    International Nuclear Information System (INIS)

    Olinto, A.V.

    1987-10-01

    We dicuss the role of quark matter in astrophysics and cosmology. The implications of the dynamics of the quark-hadron phase transition in the early universe for the element abundances from big bang nucleosynthesis and the composition of the dark matter in the universe are addressed. We discuss the possibility of deciding on an equation of state for high density matter by observing the cooling of a neutron star remnant of SN1987A. Quark matter models for the Centauros events, Cygnus X-3 cosmic ray events, high energy gamma-ray bursts and the solar neutrino problem are described. 25 refs., 3 figs

  8. Neutron quality factor

    International Nuclear Information System (INIS)

    1995-06-01

    Both the International Commission on Radiological Protection (ICRP) and the National Council on Radiation Protection and Measurements (NCRP) have recommended that the radiation quality weighting factor for neutrons (Q n , or the corresponding new modifying factor, w R ) be increased by a value of two for most radiation protection practices. This means an increase in the recommended value for Q n from a nominal value of 10 to a nominal value of 20. This increase may be interpreted to mean that the biological effectiveness of neutrons is two times greater than previously thought. A decision to increase the value of Q n will have a major impact on the regulations and radiation protection programs of Federal agencies responsible for the protection of radiation workers. Therefore, the purposes of this report are: (1) to examine the general concept of open-quotes quality factorclose quotes (Q) in radiation protection and the rationale for the selection of specific values of Q n ; and (2) to make such recommendations to the Federal agencies, as appropriate. This report is not intended to be an exhaustive review of the scientific literature on the biological effects of neutrons, with the aim of defending a particular value for Q n . Rather, the working group examined the technical issues surrounding the current recommendations of scientific advisory bodies on this matter, with the aim of determining if these recommendations should be adopted by the Federal agencies. Ultimately, the group concluded that there was no compelling basis for a change in Q n . The report was prepared by Federal scientists working under the auspices of the Science Panel of the Committee on Interagency Radiation Research and Policy Coordination (CIRRPC)

  9. Small angle neutron scattering

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of

  10. Recent advances in fast neutron radiography for cargo inspection

    International Nuclear Information System (INIS)

    Sowerby, B.D.; Tickner, J.R.

    2007-01-01

    Fast neutron radiography techniques are attractive for screening cargo for contraband such as narcotics and explosives. Neutrons have the required penetration, they interact with matter in a manner complementary to X-rays and they can be used to determine elemental composition. Compared to neutron interrogation techniques that measure secondary radiation (neutron or gamma-rays), neutron radiography systems are much more efficient and rapid and they are much more amenable to imaging. However, for neutron techniques to be successfully applied to cargo screening, they must demonstrate significant advantages over well-established X-ray techniques. This paper reviews recent developments and applications of fast neutron radiography for cargo inspection. These developments include a fast neutron and gamma-ray radiography system that utilizes a 14 MeV neutron generator as well as fast neutron resonance radiography systems that use variable energy quasi-monoenergetic neutrons and pulsed broad energy neutron beams. These systems will be discussed and compared with particular emphasis on user requirements, sources, detector systems, imaging ability and performance

  11. Rotating relativistic neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Weber, F.; Glendenning, N.K.

    1991-07-21

    Models of rotating neutron stars are constructed in the framework of Einstein's theory of general relativity. For this purpose a refined version of Hartle's method is applied. The properties of these objects, e.g. gravitational mass, equatorial and polar radius, eccentricity, red- and blueshift, quadrupole moment, are investigated for Kepler frequencies of 4000 s{sup {minus}1} {le} {Omega}{sub K} {le} 9000 s{sup {minus}1}. Therefore a self-consistency problem inherent in the determination of {Omega}{sub K} must be solved. The investigation is based on neutron star matter equations of state derived from the relativistic Martin-Schwinger hierarch of coupled Green's functions. By means of introducing the Hartree, Hartree-Fock, and ladder ({Lambda}) approximations, models of the equation of state derived. A special feature of the latter approximation scheme is the inclusion of dynamical two-particle correlations. These have been calculated from the relativistic T-matrix applying both the HEA and Bonn meson-exchange potentials of the nucleon-nucleon force. The nuclear forces of the former two treatments are those of the standard scalar-vector-isovector model of quantum hadron dynamics, with parameters adjusted to the nuclear matter data. An important aspect of this work consists in testing the compatibility of different competing models of the nuclear equation of state with data on pulsar periods. By this the fundamental problem of nuclear physics concerning the behavior of the equation of state at supernuclear densities can be treated.

  12. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  13. Role of pions and hyperons in neutron stars and supernovae

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1987-05-01

    Neutron stars are studied in the framework of nuclear relativistic field theory. Hyperons and pions significantly soften the equation of state of neutron star matter at moderate and high density. We conjecture that they are responsible for the softening that is found to be crucial to the bounce scenario in supernova calculations. Hyperons reduce the limiting mass of neutron stars predicted by theory by one half solar mass or more, which is a large effect compared to the range in which theories of matter predict this limit to fall. 6 refs., 2 figs

  14. Industrial and technological applications of neutrons

    International Nuclear Information System (INIS)

    Fontana, M.; Rustichelli, F.

    1992-01-01

    Owing to the construction of intense neutron sources and to the remarkable progress in acquisition and elaboration equipment, neutron scattering techniques have been employed more and more not only in basic research, but also in technological areas and for the solution of specific industrial problems. This is shown by the saturation of neutron beam time available at the main European sources and by an analysis of the users' distribution. Furthermore, the condensed-matter scientific community uses neutron scattering much more often now as a reference method and as an irreplaceable complement to other already well-established techniques. The aim of this Enrico Fermi course, on which the book is based, is to provide an up-to-date picture of the main results obtained (or obtainable) by means of neutron techniques in applied research. Emphasis is placed on the information and help these techniques can offer in some major areas of condensed-matter physics and materials science and to their possible developments in the near future. The volume is basically organized in topical subjects: for each one a brief introduction to the fundamentals is given, followed by examples of the concrete or potential applications. The first half deals mainly with applications of neutron scattering to materials science (metallurgy, magnetic materials, superconductors), while the second half mainly deals with polymers, micellar fluids, interfaces and liquid crystals

  15. Some applications of polarized inelastic neutron scattering

    Indian Academy of Sciences (India)

    A brief account of applications of polarized inelastic neutron scattering in condensed matter research is given. ... the itinerant antiferromagnet chromium we demonstrate that the dynamics of the longitudinal and transverse excitations are very different, resolving a long standing puzzle concerning the slope of their dispersion.

  16. National facility for neutron beam research

    Indian Academy of Sciences (India)

    In this talk, the growth of neutron beam research (NBR) in India over the past five decades is traced beginning with research at Apsara. A range of problems in condensed matter physics could be studied at CIRUS, followed by sophisticated indegenous instrumentation and research at Dhruva. The talk ends with an overview ...

  17. General principles of neutron activation analysis

    International Nuclear Information System (INIS)

    Dostal, J.; Elson, C.

    1980-01-01

    Aspects of the principles of atomic and nuclear structure and the processes of radioactivity, nuclear transformation, and the interaction of radiations with matter which are of direct relevance to neutron activation analysis and its application to geologic materials are discussed. (L.L.)

  18. Instrumentation to handle thermal polarized neutron beams

    NARCIS (Netherlands)

    Kraan, W.H.

    2004-01-01

    In this thesis we investigate devices needed to handle the polarization of thermal neutron beams: Ï/2-flippers (to start/stop Larmor precession) and Ï-flippers (to reverse polarization/precession direction) and illustrate how these devices are used to investigate the properties of matter and of the

  19. An effective equation of state for dense matter with strangeness

    International Nuclear Information System (INIS)

    Balberg, S.; Gal, A.

    1997-01-01

    An effective equation of state which generalizes the Lattimer-Swesty equation for nuclear matter is presented for matter at supernuclear densities including strange baryons. It contains an adjustable baryon potential energy density, based on models of local potentials for the baryon-baryon interactions. The features of the equation rely on the properties of nuclei for the nucleon-nucleon interactions, and mainly on experimental data from hypernuclei for the hyperon-nucleon and hyperon-hyperon interactions. The equation is used to calculate equilibrium compositions and thermodynamic properties of high density matter with strangeness in two astrophysical contexts: neutron star matter (transparent to neutrinos) and proto-neutron star matter (opaque to neutrinos). The effective equation of state reproduces typical properties of high density matter found in theoretical microscopic models. Of these, the main result is that hyperons appear in both types of matter at about twice the nuclear saturation density, and that their appearance significantly softens the equation of state. The range of maximal masses of neutron stars found in a comprehensive parameter survey is 1.4-1.7 M s un. Another typical result is that the maximal mass of a proto-neutron star with strange baryons is higher than that of an evolved neutron star (opposite to the case of nuclear matter), setting the stage for a ''delayed collapse'' scenario. (orig.)

  20. D matter

    International Nuclear Information System (INIS)

    Shiu, Gary; Wang Liantao

    2004-01-01

    We study the properties and phenomenology of particlelike states originating from D branes whose spatial dimensions are all compactified. They are nonperturbative states in string theory and we refer to them as D matter. In contrast to other nonperturbative objects such as 't Hooft-Polyakov monopoles, D-matter states could have perturbative couplings among themselves and with ordinary matter. The lightest D particle (LDP) could be stable because it is the lightest state carrying certain (integer or discrete) quantum numbers. Depending on the string scale, they could be cold dark matter candidates with properties similar to that of WIMPs or wimpzillas. The spectrum of excited states of D matter exhibits an interesting pattern which could be distinguished from that of Kaluza-Klein modes, winding states, and string resonances. We speculate about possible signatures of D matter from ultrahigh energy cosmic rays and colliders

  1. High energy neutron radiography

    International Nuclear Information System (INIS)

    Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

    1996-01-01

    High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

  2. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  3. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  4. 2016 American Conference on Neutron Scattering (ACNS)

    International Nuclear Information System (INIS)

    Woodward, Patrick

    2017-01-01

    The 8th American Conference on Neutron Scattering (ACNS) was held July 10-14, 2016 in Long Beach California, marking the first time the meeting has been held on the west coast. The meeting was coordinated by the Neutron Scattering Society of America (NSSA), and attracted 285 attendees. The meeting was chaired by NSSA vice president Patrick Woodward (the Ohio State University) assisted by NSSA president Stephan Rosenkranz (Argonne National Laboratory) together with the local organizing chair, Brent Fultz (California Institute of Technology). As in past years the Materials Research Society assisted with planning, logistics and operation of the conference. The science program was divided into the following research areas: (a) Sources, Instrumentation, and Software; (b) Hard Condensed Matter; (c) Soft Matter; (d) Biology; (e) Materials Chemistry and Materials for Energy; (f) Engineering and Industrial Applications; and (g) Neutron Physics.

  5. 2016 American Conference on Neutron Scattering (ACNS)

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, Patrick [Materials Research Society, Warrendale, PA (United States)

    2017-02-09

    The 8th American Conference on Neutron Scattering (ACNS) was held July 10-14, 2016 in Long Beach California, marking the first time the meeting has been held on the west coast. The meeting was coordinated by the Neutron Scattering Society of America (NSSA), and attracted 285 attendees. The meeting was chaired by NSSA vice president Patrick Woodward (the Ohio State University) assisted by NSSA president Stephan Rosenkranz (Argonne National Laboratory) together with the local organizing chair, Brent Fultz (California Institute of Technology). As in past years the Materials Research Society assisted with planning, logistics and operation of the conference. The science program was divided into the following research areas: (a) Sources, Instrumentation, and Software; (b) Hard Condensed Matter; (c) Soft Matter; (d) Biology; (e) Materials Chemistry and Materials for Energy; (f) Engineering and Industrial Applications; and (g) Neutron Physics.

  6. Dark Matter

    International Nuclear Information System (INIS)

    Holt, S. S.; Bennett, C. L.

    1995-01-01

    These proceedings represent papers presented at the Astrophysics conference in Maryland, organized by NASA Goddard Space Flight Center and the University of Maryland. The topics covered included low mass stars as dark matter, dark matter in galaxies and clusters, cosmic microwave background anisotropy, cold and hot dark matter, and the large scale distribution and motions of galaxies. There were eighty five papers presented. Out of these, 10 have been abstracted for the Energy Science and Technology database

  7. Continuous energy Neutron Transport Monte Carlo Simulator Project: Decomposition of the neutron energy spectrum by target nuclei tagging

    Energy Technology Data Exchange (ETDEWEB)

    Barcellos, Luiz Felipe F.C.; Bodmann, Bardo E.J.; Vilhena, Marco T.M.B., E-mail: luizfelipe.fcb@gmail.com, E-mail: bardo.bodmann@ufrgs.br, E-mail: mtmbvilhena@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Grupo de Estudos Nucleares; Leite, Sergio Q. Bogado, E-mail: sbogado@ibest.com.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    In this work a Monte Carlo simulator with continuous energy is used. This simulator distinguishes itself by using the sum of three probability distributions to represent the neutron spectrum. Two distributions have known shape, but have varying population of neutrons in time, and these are the fission neutron spectrum (for high energy neutrons) and the Maxwell-Boltzmann distribution (for thermal neutrons). The third distribution has an a priori unknown and possibly variable shape with time and is determined from parametrizations of Monte Carlo simulation. It is common practice in neutron transport calculations, e.g. multi-group transport, to consider that the neutrons only lose energy with each scattering reaction and then to use a thermal group with a Maxwellian distribution. Such an approximation is valid due to the fact that for fast neutrons up-scattering occurrence is irrelevant, being only appreciable at low energies, i.e. in the thermal energy region, in which it can be regarded as a Maxwell-Boltzmann distribution for thermal equilibrium. In this work the possible neutron-matter interactions are simulated with exception of the up-scattering of neutrons. In order to preserve the thermal spectrum, neutrons are selected stochastically as being part of the thermal population and have an energy attributed to them taken from a Maxwellian distribution. It is then shown how this procedure can emulate the up-scattering effect by the increase in the neutron population kinetic energy. Since the simulator uses tags to identify the reactions it is possible not only to plot the distributions by neutron energy, but also by the type of interaction with matter and with the identification of the target nuclei involved in the process. This work contains some preliminary results obtained from a Monte Carlo simulator for neutron transport that is being developed at Federal University of Rio Grande do Sul. (author)

  8. Dark Matter

    International Nuclear Information System (INIS)

    Bashir, A.; Cotti, U.; De Leon, C. L.; Raya, A; Villasenor, L.

    2008-01-01

    One of the biggest scientific mysteries of our time resides in the identification of the particles that constitute a large fraction of the mass of our Universe, generically known as dark matter. We review the observations and the experimental data that imply the existence of dark matter. We briefly discuss the properties of the two best dark-matter candidate particles and the experimental techniques presently used to try to discover them. Finally, we mention a proposed project that has recently emerged within the Mexican community to look for dark matter

  9. Neutron Therapy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutron Therapy Facility provides a moderate intensity, broad energy spectrum neutron beam that can be used for short term irradiations for radiobiology (cells)...

  10. Hot neutron stars at birth and energy release

    International Nuclear Information System (INIS)

    Takatsuka, Tatsuyuki

    1994-01-01

    For the discussion of hot neutron stars at birth, it is necessary to calculate the equation of state for a so-called 'supernova matter' consisting of a neutron-rich nuclear matter and degenerated leptons. One of the aims of this paper is to obtain the realistic results for the equation of state. In 10-20s after the birth, new born hot neutron stars are cooled down by neutrino diffusion process, and gradually contract to usual cold neutron starts. It is another aim of this paper to determine how much energy is released during this cooling stage. The points to which attention was paid are explained. A three-nucleon interaction was introduced phenomenologically, as a two-nucleon interaction is insufficient to satisfy the empirical saturation property of symmetric nuclear matters. The separation of uncertain part from well-known part has the merit to clarify the dependence of the results on the present theoretical uncertainties. The validity of the simplified calculation as an approximation for the exact calculation is discussed. The results by both calculations were compared for the case of hot symmetric nuclear matters. The comparison of the density profiles for a hot neutron star and a cold neutron star is shown. The binding energy for hot and cold neutron stars was plotted. These results are examined. (K.I.)

  11. Matter composition at high density by effective scaled lagrangian

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Chang Ho; Min, Dong Pil [Dept. of Physics, Seoul National Univ., Seoul (Korea, Republic of)

    1998-06-01

    We investigate the matter composition at around the neutron star densities with a model lagrangian satisfying Brown-Rho scaling law. We calculate the neutron star properties such as maximum mass, radius, hyperon compositions and central density. We compare our results with those of Walecka model. (orig.)

  12. Calculations of neutron spectra after neutron-neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, B E [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Stephenson, S L [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Howell, C R [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Mitchell, G E [North Carolina State University, Raleigh, NC 27695-8202 (United States); Tornow, W [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Furman, W I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lychagin, E V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Muzichka, A Yu [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nekhaev, G V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Strelkov, A V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Sharapov, E I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Shvetsov, V N [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2004-09-01

    A direct neutron-neutron scattering length, a{sub nn}, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of a{sub nn} will not only help resolve conflicting results of a{sub nn} by indirect means, but also in comparison to the proton-proton scattering length, a{sub pp}, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum-Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal-thermal and thermal-epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

  13. Effective interaction: From nuclear reactions to neutron stars

    Indian Academy of Sciences (India)

    pact stars. The nuclear EoS for β-equilibrated neutron star (NS) matter obtained using density-dependent effective nucleon–nucleon interaction satisfies the constraints from the observed flow data from heavy-ion collisions. The energy density of quark matter is lower than that of the nuclear EoS at higher densities implying ...

  14. A Double-Crystal Monochromator for Neutron Stress Diffractometry

    Czech Academy of Sciences Publication Activity Database

    Em, V.; Balagurov, A. M.; Glazkov, V. P.; Karpov, I. D.; Mikula, Pavol; Miron, N. F.; Somenkov, V. A.; Sumin, V. V.; Šaroun, Jan; Shushunov, M. N.

    2017-01-01

    Roč. 60, č. 4 (2017), s. 526-532 ISSN 0020-4412 Institutional support: RVO:61389005 Keywords : neutron diffraction * double-crystal * monochromator Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.437, year: 2016

  15. Merger of binary neutron stars: Gravitational waves and electromagnetic counterparts

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Masaru

    2016-12-15

    Late inspiral and merger phases of binary neutron stars are the valuable new experimental fields for exploring nuclear physics because (i) gravitational waves from them will bring information for the neutron-star equation of state and (ii) the matter ejected after the onset of the merger could be the main site for the r-process nucleosynthesis. We will summarize these aspects of the binary neutron stars, describing the current understanding for the merger process of binary neutron stars that has been revealed by numerical-relativity simulations.

  16. Observational constraints on neutron star masses and radii

    Energy Technology Data Exchange (ETDEWEB)

    Coleman Miller, M. [University of Maryland, Department of Astronomy and Joint Space-Science Institute, College Park, MD (United States); Lamb, Frederick K. [University of Illinois at Urbana-Champaign, Center for Theoretical Astrophysics and Department of Physics, Urbana, IL (United States); University of Illinois at Urbana-Champaign, Department of Astronomy, Urbana, IL (United States)

    2016-03-15

    Precise and reliable measurements of the masses and radii of neutron stars with a variety of masses would provide valuable guidance for improving models of the properties of cold matter with densities above the saturation density of nuclear matter. Several different approaches for measuring the masses and radii of neutron stars have been tried or proposed, including analyzing the X-ray fluxes and spectra of the emission from neutron stars in quiescent low-mass X-ray binary systems and thermonuclear burst sources; fitting the energy-dependent X-ray waveforms of rotation-powered millisecond pulsars, burst oscillations with millisecond periods, and accretion-powered millisecond pulsars; and modeling the gravitational radiation waveforms of coalescing double neutron star and neutron star - black hole binary systems. We describe the strengths and weaknesses of these approaches, most of which currently have substantial systematic errors, and discuss the prospects for decreasing the systematic errors in each method. (orig.)

  17. Advances in 14 MeV neutron activation analysis by means of a new intense neutron source

    International Nuclear Information System (INIS)

    Pepelnik, R.; Fanger, H.-U.; Michaelis, W.; Anders, B.

    1982-01-01

    A new intense 14 MeV neutron generator with cylindrical acceleration structure has been put in operation at the GKSS Research Center Geesthacht. The sealed neutron tube is combined with a fast pneumatic rabbit system with particular capabilities for neutron activation analysis involving short-lived reaction products. The sample transfer time is less than 140 ms. The maximum neutron flux available for activation is 5.2x10 10 n/cm 2 s. Theoretical sensitivity predictions made in a previous study have been verified for some important trace elements. As a first application, samples of freeze-dried suspended matter and fishes of the Elbe river were analyzed. (author)

  18. Gravitational effects of condensate dark matter on compact stellar objects

    International Nuclear Information System (INIS)

    Li, X.Y.; Wang, F.Y.; Cheng, K.S.

    2012-01-01

    We study the gravitational effect of non-self-annihilating dark matter on compact stellar objects. The self-interaction of condensate dark matter can give high accretion rate of dark matter onto stars. Phase transition to condensation state takes place when the dark matter density exceeds the critical value. A compact degenerate dark matter core is developed and alter the structure and stability of the stellar objects. Condensate dark matter admixed neutron stars is studied through the two-fluid TOV equation. The existence of condensate dark matter deforms the mass-radius relation of neutron stars and lower their maximum baryonic masses and radii. The possible effects on the Gamma-ray Burst rate in high redshift are discussed

  19. A weight limit emerges for neutron stars

    Science.gov (United States)

    Cho, Adrian

    2018-02-01

    Astrophysicists have long wondered how massive a neutron star—the corpse of certain exploding stars—could be without collapsing under its own gravity to form a black hole. Now, four teams have independently deduced a mass limit for neutron stars of about 2.2 times the mass of the sun. To do so, all four groups analyzed last year's blockbuster observations of the merger of two neutron stars, spied on 17 September 2017 by dozens of observatories. That approach may seem unpromising, as it might appear that the merging neutron stars would have immediately produced a black hole. However, the researchers argue that the merger first produced a spinning, overweight neutron star momentarily propped up by centrifugal force. They deduce that just before it collapsed, the short-lived neutron star had to be near the maximum mass for one spinning as a solid body. That inference allowed them to use a scaling relationship to estimate the maximum mass of a nonrotating, stable neutron star, starting from the total mass of the original pair and the amount of matter spewed into space.

  20. Neutron therapy in the 21. century

    International Nuclear Information System (INIS)

    Kroc, Thomas K.; Welsh, James S.

    2015-01-01

    The question of whether or not neutron therapy works has been answered. It is a qualified yes, as is the case with all of radiation therapy. But, neutron therapy has not kept pace with the rest of radiation therapy in terms of beam delivery techniques. Modern photon and proton based external beam radiotherapy routinely implements image-guidance, beam intensity-modulation and 3-dimensional treatment planning. The current iteration of fast neutron radiotherapy does not. Addressing these deficiencies, however, is not a matter of technology or understanding, but resources. The future of neutron therapy lies in better understanding the interaction processes of radiation with living tissue. A combination of radiobiology and computer simulations is required in order to optimise the use of neutron therapy. The questions that need to be answered are: Can we connect the macroscopic with the microscopic? What is the optimum energy? What is the optimum energy spectrum? Can we map the sensitivity of the various tissues of the human body and use that knowledge to our advantage? And once we gain a better understanding of the above radiobiological issues will we be able to capitalise on this understanding by precisely and accurately delivering fast neutrons in a manner comparable to what is now possible with photons and protons? This presentation will review the accomplishments to date. It will then lay out the questions that need to be answered for neutron therapy to truly be a 21. century therapy. (authors)