WorldWideScience

Sample records for warm-dense matter experiments

  1. Ion Beam Driven Warm Dense Matter Experiments

    Science.gov (United States)

    Bieniosek, F. M.; Henestroza, E.; Leitner, M. A.; Lidia, S. M.; Logan, B. G.; More, R. M.; Ni, P. A.; Seidl, P. A.; Waldron, W. L.; Barnard, J. J.

    2008-11-01

    We report plans and experimental results in ion beam-driven warm dense matter (WDM) experiments. Initial experiments use a 0.3 MeV K+ beam from the NDCX-I accelerator. The WDM conditions are to be achieved by longitudinal and transverse neutralized drift compression to provide a hot spot on the target with a 1-mm beam spot size, and 2-ns pulse length. As a technique for heating matter to high energy density, intense ion beams can deliver precise and uniform beam energy deposition, in a relatively large sample size, and can heat any solid-phase target material. The range of the beams in solid targets is less than 1 micron, which can be lengthened by using reduced density porous targets. We have developed a WDM target chamber and target diagnostics including a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial experiments will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  2. Ion-beam-driven warm dense matter experiments

    Science.gov (United States)

    Bieniosek, F. M.; Barnard, J. J.; Friedman, A.; Henestroza, E.; Jung, J. Y.; Leitner, M. A.; Lidia, S.; Logan, B. G.; More, R. M.; Ni, P. A.; Roy, P. K.; Seidl, P. A.; Waldron, W. L.

    2010-08-01

    As a technique for heating matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition to a relatively large sample. The US heavy ion fusion science program has developed techniques for heating and diagnosing warm dense matter (WDM) targets. We have developed a WDM target chamber and a suite of target diagnostics including a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments heat targets by both the compressed and uncompressed parts of the NDCX-I beam, and explore measurement of temperature, droplet formation and other target parameters. Continued improvements in beam tuning, bunch compression, and other upgrades are expected to yield higher temperature and pressure in the WDM targets. Future experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  3. Warm Dense Matter Experiments Driven by Ion Beams

    Science.gov (United States)

    Bieniosek, F. M.; Henestroza, E.; Jung, J. Y.; Leitner, M. A.; Lidia, S.; Logan, B. G.; More, R. M.; Ni, P. A.; Roy, P. K.; Seidl, P. A.; Waldron, W. L.; Barnard, J. J.; Friedman, A.

    2009-11-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. We present results from warm dense matter (WDM) experiments at NDCX-I. The 0.3 MeV, 30-mA K^+ beam from the NDCX-I accelerator heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam to a spot size ˜ 1 mm, and compressed pulse length ˜ 2 ns. The uncompressed beam flux is >=500 kW/cm^2, and the compressed pulse flux is > 5 MW/cm^2. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. Future plans include construction of the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-4 MeV lithium ion beam. We have developed a target chamber and target diagnostics including a fast multi-channel optical pyrometer, optical streak camera, and high-speed gated cameras. We compare measurements of temperature, droplet formation and other target parameters with model predictions. Continued improvements in beam tuning, bunch compression, and other upgrades are expected to yield higher flux on target.

  4. Warm Dense Matter: An Overview

    Energy Technology Data Exchange (ETDEWEB)

    Kalantar, D H; Lee, R W; Molitoris, J D

    2004-04-21

    This document provides a summary of the ''LLNL Workshop on Extreme States of Materials: Warm Dense Matter to NIF'' which was held on 20, 21, and 22 February 2002 at the Wente Conference Center in Livermore, CA. The warm dense matter regime, the transitional phase space region between cold material and hot plasma, is presently poorly understood. The drive to understand the nature of matter in this regime is sparking scientific activity worldwide. In addition to pure scientific interest, finite temperature dense matter occurs in the regimes of interest to the SSMP (Stockpile Stewardship Materials Program). So that obtaining a better understanding of WDM is important to performing effective experiments at, e.g., NIF, a primary mission of LLNL. At this workshop we examined current experimental and theoretical work performed at, and in conjunction with, LLNL to focus future activities and define our role in this rapidly emerging research area. On the experimental front LLNL plays a leading role in three of the five relevant areas and has the opportunity to become a major player in the other two. Discussion at the workshop indicated that the path forward for the experimental efforts at LLNL were two fold: First, we are doing reasonable baseline work at SPLs, HE, and High Energy Lasers with more effort encouraged. Second, we need to plan effectively for the next evolution in large scale facilities, both laser (NIF) and Light/Beam sources (LCLS/TESLA and GSI) Theoretically, LLNL has major research advantages in areas as diverse as the thermochemical approach to warm dense matter equations of state to first principles molecular dynamics simulations. However, it was clear that there is much work to be done theoretically to understand warm dense matter. Further, there is a need for a close collaboration between the generation of verifiable experimental data that can provide benchmarks of both the experimental techniques and the theoretical capabilities

  5. Diagnostics for heavy ion beam driven Warm dense matter experiments

    Science.gov (United States)

    Ni, Pavel; Bieniosek, Frank; Lidia, Steve; Seidl, Peter; Waldron, Will

    2009-11-01

    A set of diagnostic has been developed for the WDM experiments at Berkeley. The diagnostics are aimed at the in-situ measurement of temperature, expansion velocity and pressure of a WDM sample.A specially developed two-channel pyrometer probes color temperatures at 750 nm,1000 nm and 1400 nm, with 75 ps temporal resolution. The system has a broad dynamic range with a lower limit ˜2000 K and upper limit ˜100000 K. The pyrometer design is based on custom spectrally selective beam splitters and can be upgraded up to seven channels. Continuous target emission from 450 nm to 850 nm is recorder by a custom spectrometer, consisting of a high dynamic range Hamamatsu streak camera and a holographic grating. The system is calibrated absolutely with a tungsten ribbon lamp (NIST traceable). The various sweeping times of the streak unit allows for temporal resolution varying from 1 ps to 1 us. The spectrometer has a lower sensitivity than the pyrometer and applied in experiments with higher temperatures. Hydrodynamic expansion velocity of a target's free surface is measured by a commercially available all- fiber Doppler shift laser interferometer (VISAR). The installed delay etalon allows for velocity detection with 2 m/s precision and 0.5 ns resolution.

  6. Beam Steering, Focusing and Compression for Warm-Dense Matter Experiments

    Science.gov (United States)

    Lidia, S. M.; Anders, A.; Cohen, R. H.; Coleman, J. E.; Dorf, M.; Gilson, E. P.; Grote, D. P.; Jung, J. Y.; Leitner, M.; Logan, B. G.; Roy, P. K.; Sefkow, A. B.; Seidl, P. A.; Waldron, W. L.; Welch, D. R.

    2008-11-01

    The Heavy-Ion Fusion Sciences Virtual National Laboratory is pursuing an approach to target heating experiments in the Warm Dense Matter regime, using space-charge-dominated ion beams that are simultaneously longitudinally bunched and transversely focused. Axial compression leading to ˜100X current amplification and simultaneous radial focusing have led to encouraging energy deposition approaching, but still short of, the intensities required for eV-range target heating experiments. We present measurements from the Neutralized Drift Compression Experiment to reach the necessary higher beam intensities, including: (1) axial compression and radial focusing; (2) spatial and temporal distribution of energy deposition at the target plane; and (3) centroid motion of the beam spot through the pulse.

  7. DPIS for warm dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, K.; Kanesue, T.; Horioka, K.; Okamura, M.

    2010-05-23

    Warm Dense Matter (WDM) offers an challenging problem because WDM, which is beyond ideal plasma, is in a low temperature and high density state with partially degenerate electrons and coupled ions. WDM is a common state of matter in astrophysical objects such as cores of giant planets and white dwarfs. The WDM studies require large energy deposition into a small target volume in a shorter time than the hydrodynamical time and need uniformity across the full thickness of the target. Since moderate energy ion beams ({approx} 0.3 MeV/u) can be useful tool for WDM physics, we propose WDM generation using Direct Plasma Injection Scheme (DPIS). In the DPIS, laser ion source is connected to the Radio Frequency Quadrupole (RFQ) linear accelerator directly without the beam transport line. DPIS with a realistic final focus and a linear accelerator can produce WDM.

  8. Progress in beam focusing and compression for warm-dense matter experiments

    Science.gov (United States)

    Seidl, P. A.; Anders, A.; Bieniosek, F. M.; Barnard, J. J.; Calanog, J.; Chen, A. X.; Cohen, R. H.; Coleman, J. E.; Dorf, M.; Gilson, E. P.; Grote, D. P.; Jung, J. Y.; Leitner, M.; Lidia, S. M.; Logan, B. G.; Ni, P.; Roy, P. K.; Van den Bogert, K.; Waldron, W. L.; Welch, D. R.

    2009-07-01

    The Heavy-Ion Fusion Sciences Virtual National Laboratory is pursuing an approach to target heating experiments in the warm-dense matter regime, using space-charge-dominated ion beams that are simultaneously longitudinally bunched and transversely focused. Longitudinal beam compression by large factors has been demonstrated in the Neutralized Drift Compression Experiment (NDCX) with controlled ramps and forced neutralization. Using an injected 30-mA K + ion beam with initial kinetic energy 0.3 MeV, axial compression leading to ˜50-fold current amplification and simultaneous radial focusing to beam radii of a few mm have led to encouraging energy deposition approaching the intensities required for eV-range target heating experiments. We discuss the status of several improvements to our Neutralized Drift Compression Experiment and associated beam diagnostics that are under development to reach the necessary higher beam intensities, including (1) greater axial compression via a longer velocity ramp using a new bunching module with approximately twice the available volt seconds (Vs); (2) improved centroid control via beam steering dipoles to mitigate aberrations in the bunching module; (3) time-dependent focusing elements to correct considerable chromatic aberrations; and (4) plasma injection improvements to establish a plasma density always greater than the beam density, expected to be >10 13 cm -3.

  9. Proton acceleration experiments and warm dense matter research using high power lasers

    Energy Technology Data Exchange (ETDEWEB)

    Roth, M; Alber, I; Guenther, M; Harres, K [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Bagnoud, V [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Brown, C R D [Plasma Physics Group, Imperial College London, SW7 2BZ (United Kingdom); Clarke, R; Heathcote, R; Li, B [STFC, Rutherford Appleton Laboratory (RAL), Chilton, Didcot, OX14 OQX (United Kingdom); Daido, H [Photo Medical Research Center, JAEA, Kizugawa-City, Kyoto 619-0215 (Japan); Fernandez, J; Flippo, K; Gaillard, S; Gauthier, C [Los Alamos National Laboratory (LANL), Los Alamos, NM 87545 (United States); Geissel, M [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Glenzer, S; Kritcher, A; Kugland, N; LePape, S [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Gregori, G, E-mail: markus.roth@physik.tu-darmstadt.d [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2009-12-15

    The acceleration of intense proton and ion beams by ultra-intense lasers has matured to a point where applications in basic research and technology are being developed. Crucial for harvesting the unmatched beam parameters driven by the relativistic electron sheath is the precise control of the beam. In this paper we report on recent experiments using the PHELIX laser at GSI, the VULCAN laser at RAL and the TRIDENT laser at LANL to control and use laser accelerated proton beams for applications in high energy density research. We demonstrate efficient collimation of the proton beam using high field pulsed solenoid magnets, a prerequisite to capture and transport the beam for applications. Furthermore, we report on two campaigns to use intense, short proton bunches to isochorically heat solid targets up to the warm dense matter state. The temporal profile of the proton beam allows for rapid heating of the target, much faster than the hydrodynamic response time thereby creating a strongly coupled plasma at solid density. The target parameters are then probed by x-ray Thomson scattering to reveal the density and temperature of the heated volume. This combination of two powerful techniques developed during the past few years allows for the generation and investigation of macroscopic samples of matter in states present in giant planets or the interior of the earth.

  10. Results from an Orion proton heating experiment for Warm Dense Matter studies

    Science.gov (United States)

    Allan, Peter; James, Steven; Brown, Colin; Hobbs, Lauren; Hill, Matthew; Hoarty, David; Chen, Hui; Hazi, Andy; AWE Team; LLNL Team

    2014-10-01

    The properties of warm dense matter covering densities and temperatures in the ranges 0.1-10x solid and 1-100eV, fall between ideal plasma and condensed matter theories. Studies have highlighted uncertainties in EoS predictions using methods based on the Thomas-Fermi and ion-cell models. In particular, such models predict large departures from ideal gas behaviour for low Z material at low densities and temperatures. In an extension of previous work, material has been isochorically heated using short-pulse laser-generated proton beams. Here, the method of Foord et al. was used toinfer isentropes oflow Z materials and provide data to validate model predictions. Earlier measurements were limited by the eV backlighterenergy to relatively low densities and pressures below 1.5Mbar, and were conducted in cylindrical geometry. More recent experiments performed at the Orion laser use a parabolic crystal imaging system in order to measure to higher pressures by probing planar expansion of aluminium foils at 1.8keV. The imaging system is described and results are presented showing a spatial resolution of 6um, which was then streaked to give temporal resolution of 10ps. Preliminary analysis of the foil expansion indicates a peak temperature of 30eV. The proton and ion spectra used to heat the sample were measured by a magnetic spectrometer and a Thomson parabola. These results are presented and the effect on the measured expansion discussed. Plans for future measurements are discussed in the light of results obtained so far.

  11. Frontiers and challenges in warm dense matter

    CERN Document Server

    Desjarlais, Michael; Redmer, Ronald; Trickey, Samuel

    2014-01-01

    Warm Dense Matter (WDM) occupies a loosely defined region of phase space intermediate between solid, liquid, gas, and plasma, and typically shares characteristics of two or more of these phases. WDM is generally associated with the combination of strongly coupled ions and moderately degenerate electrons, and careful attention to quantum physics and electronic structure is essential. The lack of a small perturbation parameter greatly limits approximate attempts at its accurate description. Since WDM resides at the intersection of solid state and high energy density physics, many high energy density physics (HEDP) experiments pass through this difficult region of phase space. Thus, understanding and modeling WDM is key to the success of experiments on diverse facilities. These include the National Ignition Campaign centered on the National Ignition Facility (NIF), pulsed-power driven experiments on the Z machine, ion-beam-driven WDM experiments on the NDCX-II, and fundamental WDM research at the Linear Coherent...

  12. Modeling warm dense matter experiments using the 3D ALE-AMR code and the move toward exascale computing

    Directory of Open Access Journals (Sweden)

    Koniges Alice

    2013-11-01

    Full Text Available The Neutralized Drift Compression Experiment II (NDCX II is an induction accelerator planned for initial commissioning in 2012. The final design calls for a 3 MeV, Li+ ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and transverse dimension of order 1 mm. The NDCX II will be used in studies of material in the warm dense matter (WDM regime, and ion beam/hydrodynamic coupling experiments relevant to heavy ion based inertial fusion energy. We discuss recent efforts to adapt the 3D ALE-AMR code to model WDM experiments on NDCX II. The code, which combines Arbitrary Lagrangian Eulerian (ALE hydrodynamics with Adaptive Mesh Refinement (AMR, has physics models that include ion deposition, radiation hydrodynamics, thermal diffusion, anisotropic material strength with material time history, and advanced models for fragmentation. Experiments at NDCX-II will explore the process of bubble and droplet formation (two-phase expansion of superheated metal solids using ion beams. Experiments at higher temperatures will explore equation of state and heavy ion fusion beam-to-target energy coupling efficiency. Ion beams allow precise control of local beam energy deposition providing uniform volumetric heating on a timescale shorter than that of hydrodynamic expansion. We also briefly discuss the effects of the move to exascale computing and related computational changes on general modeling codes in fusion.

  13. Demonstration of space-resolved x-ray Thomson scattering capability for warm dense matter experiments on the Z accelerator

    Science.gov (United States)

    Ao, T.; Harding, E. C.; Bailey, J. E.; Lemke, R. W.; Desjarlais, M. P.; Hansen, S. B.; Smith, I. C.; Geissel, M.; Maurer, A.; Reneker, J.; Romero, D.; Sinars, D. B.; Rochau, G. A.; Benage, J. F.

    2016-03-01

    Experiments on the Sandia Z pulsed-power accelerator have demonstrated the ability to produce warm dense matter (WDM) states with unprecedented uniformity, duration, and size, which are ideal for investigations of fundamental WDM properties. For the first time, space-resolved x-ray Thomson scattering (XRTS) spectra from shocked carbon foams were recorded on Z. The large (>20 MA) electrical current produced by Z was used to launch Al flyer plates up to 25 km/s. The impact of the flyer plate on a CH2 foam target produced a shocked state with an estimated pressure of 0.75 Mbar, density of 0.52 g/cm3, and temperature of 4.3 eV. Both unshocked and shocked portions of the foam target were probed with 6.2 keV x-rays produced by focusing the Z-Beamlet laser onto a nearby Mn foil. The data are composed of three spatially distinct spectra that were simultaneously captured with a single spectrometer with high spectral (4.8 eV) and spatial (190 μm) resolutions. Detailed spectral information from three target locations is provided simultaneously: the incident x-ray source, the scattered signal from unshocked foam, and the scattered signal from shocked foam.

  14. Experimental Studies of the Transport Parameters of Warm Dense Matter

    Energy Technology Data Exchange (ETDEWEB)

    Chouffani, Khalid [Idaho State Univ., Pocatello, ID (United States)

    2014-12-01

    There is a need to establish fundamental properties of matter and energy under extreme physical conditions. Although high energy density physics (HEDP) research spans a wide range of plasma conditions, there is one unifying regime that is of particular importance and complexity: that of warm dense matter, the transitional state between solid state condensed matter and energetic plasmas. Most laboratory experimental conditions, including inertial confinement implosion, fall into this regime. Because all aspects of laboratory-created high-energy-density plasmas transition through the warm dense matter regime, understanding the fundamental properties to determine how matter and energy interact in this regime is an important aspect of major research efforts in HEDP. Improved understanding of warm dense matter would have significant and wide-ranging impact on HEDP science, from helping to explain wire initiation studies on the Sandia Z machine to increasing the predictive power of inertial confinement fusion modeling. The central goal or objective of our proposed research is to experimentally determine the electrical resistivity, temperature, density, and average ionization state of a variety of materials in the warm dense matter regime, without the use of theoretical calculations. Since the lack of an accurate energy of state (EOS) model is primarily due to the lack of experimental data, we propose an experimental study of the transport coefficients of warm dense matter.

  15. Thermal conductivity measurements of proton-heated warm dense matter

    Science.gov (United States)

    McKelvey, A.; Fernandez-Panella, A.; Hua, R.; Kim, J.; King, J.; Sio, H.; McGuffey, C.; Kemp, G. E.; Freeman, R. R.; Beg, F. N.; Shepherd, R.; Ping, Y.

    2015-06-01

    Accurate knowledge of conductivity characteristics in the strongly coupled plasma regime is extremely important for ICF processes such as the onset of hydrodynamic instabilities, thermonuclear burn propagation waves, shell mixing, and efficient x-ray conversion of indirect drive schemes. Recently, an experiment was performed on the Titan laser platform at the Jupiter Laser Facility to measure the thermal conductivity of proton-heated warm dense matter. In the experiment, proton beams generated via target normal sheath acceleration were used to heat bi-layer targets with high-Z front layers and lower-Z back layers. The stopping power of a material is approximately proportional to Z2 so a sharp temperature gradient is established between the two materials. The subsequent thermal conduction from the higher-Z material to the lower-Z was measured with time resolved streaked optical pyrometry (SOP) and Fourier domain interferometry (FDI) of the rear surface. Results will be used to compare predictions from the thermal conduction equation and the Wiedemann-Franz Law in the warm dense matter regime. Data from the time resolved diagnostics for Au/Al and Au/C Targets of 20-200 nm thickness will be presented.

  16. Ab initio thermodynamic results for warm dense matter

    Science.gov (United States)

    Bonitz, Michael

    2016-10-01

    Warm dense matter (WDM) - an exotic state where electrons are quantum degenerate and ions may be strongly correlated - is ubiquitous in dense astrophysical plasmas and highly compressed laboratory systems including inertial fusion. Accurate theoretical predictions require precision thermodynamic data for the electron gas at high density and finite temperature around the Fermi temperature. First such data have been obtained by restricted path integral Monte Carlo (restricted PIMC) simulations and transformed into analytical fits for the free energy. Such results are also key input for novel finite temperature density functional theory. However, the RPIMC data of Ref. 1 are limited to moderate densities, and even there turned out to be surprisingly inaccurate, which is a consequence of the fermion sign problem. These problems were recently overcome by the development of alternative QMC approaches in Kiel (configuration PIMC and permutation blocking PIMC) and Imperial College (Density matrix QMC). The three methods have their strengths and limitations in complementary parameter regions and provide highly accurate thermodynamic data for the electronic contributions in WDM. While the original results were obtained for small particle numbers, recently accurate finite size corrections were derived allowing to compute ab initio thermodynamic data with an unprecedented accuracy of better than 0.3 percent. This provides the final step for the use as benchmark data for experiments and models of Warm dense matter. Co-authors: T. Schoof, S. Groth, T. Dornheim, F. D. Malone, M. Foulkes, and T. Sjostroem, Funded by: DFG via SFB-TR24 and project BO1366-10.

  17. Warm dense matter and Thomson scattering at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Faeustlin, Roland Rainer

    2010-05-15

    X-ray free electron lasers are powerful tools to investigate moderately to strongly correlated solid density low temperature plasmas, named warm dense matter. These plasmas are of most interest for astrophysics and laser plasma interaction, particularly inertial confinement fusion. This work utilizes the ultrashort soft x-ray pulse duration and high brilliance of the free electron laser in Hamburg, FLASH, to generate warm dense matter and to study its ultrafast processes. The techniques applied are absorption measurement, emission spectroscopy and Thomson scattering. Radiative hydrodynamics and Thomson scattering simulations are used to investigate the impact of temperature and density gradients in the sample and to fit the experimental data. The measurements result in a comprehensive picture of soft x-ray matter interaction related to warm dense matter and yield insight into ultrafast equilibration and relaxation mechanisms, in particular impact ionization and radiative recombination. (orig.)

  18. A multi-wavelength streak-optical-pyrometer for warm-dense matter experiments at NDCX-I and NDCX-II

    Science.gov (United States)

    Ni, P. A.; Bieniosek, F. M.; Henestroza, E.; Lidia, S. M.

    2014-01-01

    We report on a multi-wavelength streak-optical-pyrometer (SOP) developed the for warm-dense-matter (WDM) experiments at the existing NDCX-I facility and the NDCX-II facility currently being commissioned at LBNL. The SOP served as the primary temperature diagnostic in the recent NDCX-I experiments, in which an intense K+ beam was used to heat different metal samples into WDM states. The SOP consists of a spectral grating (visible and near-infrared spectral range) and a fast, high-dynamic-range optical streak camera. The instrument is calibrated absolutely with a NIST-traceable tungsten ribbon lamp and can itself be considered as an absolutely calibrated, time-resolving spectrometer. The sample temperature is determined from fitting the recorded thermal spectrum into the Planck formula multiplied by a model of emissivity.

  19. A multi-wavelength streak-optical-pyrometer for warm-dense matter experiments at NDCX-I and NDCX-II

    Energy Technology Data Exchange (ETDEWEB)

    Ni, P.A., E-mail: pani@lbl.gov; Bieniosek, F.M.; Henestroza, E.; Lidia, S.M.

    2014-01-01

    We report on a multi-wavelength streak-optical-pyrometer (SOP) developed the for warm-dense-matter (WDM) experiments at the existing NDCX-I facility and the NDCX-II facility currently being commissioned at LBNL. The SOP served as the primary temperature diagnostic in the recent NDCX-I experiments, in which an intense K{sup +} beam was used to heat different metal samples into WDM states. The SOP consists of a spectral grating (visible and near-infrared spectral range) and a fast, high-dynamic-range optical streak camera. The instrument is calibrated absolutely with a NIST-traceable tungsten ribbon lamp and can itself be considered as an absolutely calibrated, time-resolving spectrometer. The sample temperature is determined from fitting the recorded thermal spectrum into the Planck formula multiplied by a model of emissivity.

  20. Observations of Plasmons in Warm Dense Matter

    Energy Technology Data Exchange (ETDEWEB)

    Glenzer, S H; Landen, O L; Neumayer, P; Lee, R W; Widmann, K; Pollaine, S W; Wallace, R J; Gregori, G; Holl, A; Bornath, T; Thiele, R; Schwarz, V; Kraeft, W; Redmer, R

    2006-09-05

    We present the first collective x-ray scattering measurements of plasmons in solid-density plasmas. The forward scattering spectra of a laser-produced narrow-band x-ray line from isochorically heated beryllium show that the plasmon frequency is a sensitive measure of the electron density. Dynamic structure calculations that include collisions and detailed balance match the measured plasmon spectrum indicating that this technique will enable new applications to determine the equation of state and compressibility of dense matter.

  1. Optical diagnostic of warm dense matter at NDCXI

    Science.gov (United States)

    Ni, Pavel; Bieniosek, Frank; Barnard, John; Henestroza, Enrique; Lidia, Steve; More, Dick

    2010-11-01

    This work is related to recently warm dense matter experiments at Lawrence Berkeley National Laboratory (LBNL), Neutralized Drift Compression Experiment (NDCX) accelerator, which delivers a 30-mA, 350-keV K^+ ion beam. Using the recently-developed technique of neutralized drift compression, the beam is simultaneously compressed longitudinally by a factor of 50, and focused transversely down to a 1 mm spot. The beam pulse is used to pulse heat various target materials, including Al, W, C, Pt and Si, above 3000 K driving samples into two-phase, liquid-vapor states. The next generation accelerator, NDCX-II, is being built and scheduled to be accomplished in 2012. This new machine will, utilize 2 MeV Li+ ions, to heat 2 micrometer thick metal targets up to 1,5 eV in 0.5 ns. This will allow us investigate near critical points properties of matter. The talk will focus on diagnostics aspects of WDM at NDCX. The fielded diagnostics include a specially developed three-channel optical pyrometer which probes color temperatures of the target at 750 nm, 1000 nm and 1500 nm, with 75 ps temporal resolution. Continuous target emission from 450 nm to 850 nm is recorded by a custom spectrometer, consisting of a high dynamic range Hamamatsu streak camera and a holographic grating. Free expansion of the sample is measured by a VISAR. Future diagnostics for the NDX-II user facility will be also discussed.

  2. Intense Ion Beam for Warm Dense Matter Physics

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Joshua Eugene [Univ. of California, Berkeley, CA (United States)

    2008-01-01

    The Neutralized Drift Compression Experiment (NDCX) at Lawrence Berkeley National Laboratory is exploring the physical limits of compression and focusing of ion beams for heating material to warm dense matter (WDM) and fusion ignition conditions. The NDCX is a beam transport experiment with several components at a scale comparable to an inertial fusion energy driver. The NDCX is an accelerator which consists of a low-emittance ion source, high-current injector, solenoid matching section, induction bunching module, beam neutralization section, and final focusing system. The principal objectives of the experiment are to control the beam envelope, demonstrate effective neutralization of the beam space-charge, control the velocity tilt on the beam, and understand defocusing effects, field imperfections, and limitations on peak intensity such as emittance and aberrations. Target heating experiments with space-charge dominated ion beams require simultaneous longitudinal bunching and transverse focusing. A four-solenoid lattice is used to tune the beam envelope to the necessary focusing conditions before entering the induction bunching module. The induction bunching module provides a head-to-tail velocity ramp necessary to achieve peak axial compression at the desired focal plane. Downstream of the induction gap a plasma column neutralizes the beam space charge so only emittance limits the focused beam intensity. We present results of beam transport through a solenoid matching section and simultaneous focusing of a singly charged K+ ion bunch at an ion energy of 0.3 MeV. The results include a qualitative comparison of experimental and calculated results after the solenoid matching section, which include time resolved current density, transverse distributions, and phase-space of the beam at different diagnostic planes. Electron cloud and gas measurements in the solenoid lattice and in the vicinity of intercepting diagnostics are also presented. Finally

  3. Non-equilibrium Warm Dense Gold: Experiments and Simulations

    Science.gov (United States)

    Ng, Andrew

    2015-11-01

    This talk is an overview of a series of studies of non-equilibrium Warm Dense Matter using a broad range of measured properties of a single material, namely Au, as comprehensive benchmarks for theory. The measurements are made in fs-laser pump-probe experiments. For understanding lattice stability, our investigation reveals a solid phase at high energy density. This leads to the calculation of lattice dynamics using MD simulations and phonon hardening in DFT-MD simulations. For understanding electron transport in two-temperature states, AC conductivity is used to evaluate DFT-MD and Kubo-Greenwood calculations while DC conductivity is used to test Ziman calculations in a DFT average atom model. The electron density is also used to assess electronic structure calculations in DFT simulations. In our latest study of electron kinetics in states with a non-Fermi-Dirac distribution, three-body recombination is found to have a significant effect on electron thermalizaiton time. This is driving an effort to develop electron kinetics simulations using the Boltzmann equation method.

  4. ION BEAM HEATED TARGET SIMULATIONS FOR WARM DENSE MATTER PHYSICS AND INERTIAL FUSION ENERGY

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, J.J.; Armijo, J.; Bailey, D.S.; Friedman, A.; Bieniosek, F.M.; Henestroza, E.; Kaganovich, I.; Leung, P.T.; Logan, B.G.; Marinak, M.M.; More, R.M.; Ng, S.F.; Penn, G.E.; Perkins, L.J.; Veitzer, S.; Wurtele, J.S.; Yu, S.S.; Zylstra, A.B.

    2008-08-01

    Hydrodynamic simulations have been carried out using the multi-physics radiation hydrodynamics code HYDRA and the simplified one-dimensional hydrodynamics code DISH. We simulate possible targets for a near-term experiment at LBNL (the Neutralized Drift Compression Experiment, NDCX) and possible later experiments on a proposed facility (NDCX-II) for studies of warm dense matter and inertial fusion energy related beam-target coupling. Simulations of various target materials (including solids and foams) are presented. Experimental configurations include single pulse planar metallic solid and foam foils. Concepts for double-pulsed and ramped-energy pulses on cryogenic targets and foams have been simulated for exploring direct drive beam target coupling, and concepts and simulations for collapsing cylindrical and spherical bubbles to enhance temperature and pressure for warm dense matter studies are described.

  5. Ion Beam Heated Target Simulations for Warm Dense Matter Physics and Inertial Fusion Energy

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, J J; Armijo, J; Bailey, D S; Friedman, A; Bieniosek, F M; Henestroza, E; Kaganovich, I; Leung, P T; Logan, B G; Marinak, M M; More, R M; Ng, S F; Penn, G E; Perkins, L J; Veitzer, S; Wurtele, J S; Yu, S S; Zylstra, A B

    2008-08-12

    Hydrodynamic simulations have been carried out using the multi-physics radiation hydrodynamics code HYDRA and the simplified one-dimensional hydrodynamics code DISH. We simulate possible targets for a near-term experiment at LBNL (the Neutralized Drift Compression Experiment, NDCX) and possible later experiments on a proposed facility (NDCX-II) for studies of warm dense matter and inertial fusion energy related beam-target coupling. Simulations of various target materials (including solids and foams) are presented. Experimental configurations include single pulse planar metallic solid and foam foils. Concepts for double-pulsed and ramped-energy pulses on cryogenic targets and foams have been simulated for exploring direct drive beam target coupling, and concepts and simulations for collapsing cylindrical and spherical bubbles to enhance temperature and pressure for warm dense matter studies are described.

  6. Ultrabright x-ray laser scattering for dynamic warm dense matter physics

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, L. B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Univ. of California, Berkeley, CA (United States); Lee, H. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Doppner, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Galtier, E. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nagler, B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Heimann, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fortmann, C. [QuantumWise A/S, Koebenhavn (Denmark); LePape, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mao, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Millot, M. [Univ. of California, Berkeley, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pak, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Turnbull, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chapman, D. A. [AWE plc, Reading (United Kingdom); Univ. of Warwick, Coventry (United Kingdom); Gericke, D. O. [AWE plc, Reading (United Kingdom); Vorberger, J. [Max Planck Institute for the Physics of Complex Systems, Dresden (Germany); White, T. [Univ. of Oxford, Oxford (United Kingdom); Gregori, G. [Univ. of Oxford, Oxford (United Kingdom); Wei, M. [General Atomics, San Diego, CA (United States); Barbrel, B. [Univ. of California, Berkeley, CA (United States); Falcone, R. W. [Univ. of California, Berkeley, CA (United States); Kao, C. -C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nuhn, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Welch, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Zastrau, U. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Friedrich-Schiller-Univ., Jena (Germany); Neumayer, P. [GSI Helmhltzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Hastings, J. B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Glenzer, S. H. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-03-23

    In megabar shock waves, materials compress and undergo a phase transition to a dense charged-particle system that is dominated by strong correlations and quantum effects. This complex state, known as warm dense matter, exists in planetary interiors and many laboratory experiments (for example, during high-power laser interactions with solids or the compression phase of inertial confinement fusion implosions). Here, we apply record peak brightness X-rays at the Linac Coherent Light Source to resolve ionic interactions at atomic (ångström) scale lengths and to determine their physical properties. Our in situ measurements characterize the compressed lattice and resolve the transition to warm dense matter, demonstrating that short-range repulsion between ions must be accounted for to obtain accurate structure factor and equation of state data. Additionally, the unique properties of the X-ray laser provide plasmon spectra that yield the temperature and density with unprecedented precision at micrometre-scale resolution in dynamic compression experiments.

  7. Road of warm dense noble metals to the plasma state: Ab initio theory of the ultrafast structural dynamics in warm dense matter

    Science.gov (United States)

    Kabeer, Fairoja Cheenicode; Zijlstra, Eeuwe S.; Garcia, Martin E.

    2014-03-01

    Intense ultrashort extreme ultraviolet (XUV) pulses can be used to create warm dense matter in the laboratory, which then develops to a plasma state. So far, however, it is unknown, whether this transition occurs via heat transfer from hot electrons to cold atoms or nonthermally due to a lattice instability. Here we computed the response of the phonon spectra of copper and silver to the presence of XUV-excited core holes and core holes together with very hot electrons. We found that the average interatomic bonds become stronger in the warm dense state. We discuss why these findings support the above-mentioned heat transfer scenario.

  8. Droplet evolution in expanding flow of warm dense matter

    CERN Document Server

    Armijo, Julien; 10.1103/PhysRevE.83.051507

    2011-01-01

    We propose a simple, self-consistent kinetic model for the evolution of a mixture of droplets and vapor expanding adiabatically in vacuum after rapid, almost isochoric heating. We study the evolution of the two-phase fluid at intermediate times between the molecular and the hydrodynamic scales, focusing on out-of-equilibrium and surface effects. We use the van der Waals equation of state as a test bed to implement our model and study the phenomenology of the upcoming second neutralized drift compression experiment (NDCX-II) at Lawrence Berkeley National Laboratory (LBNL) that uses ion beams for target heating.We find an approximate expression for the temperature difference between the droplets and the expanding gas and we check it with numerical calculations. The formula provides a useful criterion to distinguish the thermalized and nonthermalized regimes of expansion. In the thermalized case, the liquid fraction grows in a proportion that we estimate analytically, whereas, in case of too rapid expansion, a s...

  9. A pulsed power hydrodynamics approach to exploring properties of warm dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Reinovsky, Robert Emil [Los Alamos National Laboratory

    2008-01-01

    Pulsed Power Hydrodynamics, as an application of low-impedance, pulsed power, and high magnetic field technology developed over the last decade to study advanced hydrodynamic problems, instabilities, turbulence, and material properties, can potentially be applied to the study of the behavior and properties of warm dense matter (WDM) as well. Exploration of the properties, such as equation of state and conductivity, of warm dense matter is an emerging area of study focused on the behavior of matter at density near solid density (from 10% of solid density to a few times solid density) and modest temperatures ({approx}1-10 eV). Warm dense matter conditions can be achieved by laser or particle beam heating of very small quantities of matter on timescales short compared to the subsequent hydrodynamic expansion timescales (isochoric heating) and a vigorous community of researchers is applying these techniques using petawatt scale laser systems, but the microscopic size scale of the WDM produced in this way limits access to some physics phenomena. Pulsed power hydrodynamics techniques, either through high convergence liner compression of a large volume, modest density, low temperature plasma to densities approaching solid density or through the explosion and subsequent expansion of a conductor (wire) against a high pressure (density) gas background (isobaric expansion) techniques both offer the prospect for producing warm dense matter in macroscopic quantities. However, both techniques demand substantial energy, proper power conditioning and delivery, and an understanding of the hydrodynamic and instability processes that limit each technique. Similarly, liner compression of normal density material, perhaps using multiple reflected shocks can provide access to the challenging region above normal density -- again with the requirement of very large amounts of driving energy. In this paper we will provide an introduction to techniques that might be applied to explore this

  10. The Korringa-Kohn-Rostoker Method Applied to Warm Dense Matter

    Science.gov (United States)

    Finkenstadt, Daniel; Newnam, Charles E.; Wilson, Brian G.

    2012-02-01

    The electronic structure, EOS and transport properties of warm electrons in an amorphous or disordered configuration of ions is not well described by either solid-state or plasma models. Such warm, dense systems share the characteristic of the solid state that multi-center scattering effects are of paramount importance in forming bands of valence states. Theoretical treatment of the EOS of warm, dense matter therefore requires a way to include significant occupation of higher energy and angular momentum channel continuum states. We are extending the Green's function Kohn-Korringa-Rostoker code MECCA as an all-electron (non-pseudo potential) method that treats arbitrary mixtures of atoms on an ab-initio basis over a broad range of conditions, from cold, solid matter up to hot plasmas at extreme (ICF) compression. Specific examples of Aluminum and Boron-Nitride will be discussed.

  11. Short intense ion pulses for materials and warm dense matter research

    CERN Document Server

    Seidl, Peter A; Lidia, Steven M; Persaud, Arun; Stettler, Matthew; Takakuwa, Jeffrey H; Waldron, William L; Schenkel, Thomas; Barnard, John J; Friedman, Alex; Grote, David P; Davidson, Ronald C; Gilson, Erik P; Kaganovich, Igor D

    2015-01-01

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment-II at Lawrence Berkeley National Laboratory, by generating beam spots size with radius r < 1 mm within 2 ns FWHM and approximately 10^10 ions/pulse. To enable the short pulse durations and mm-scale focal spot radii, the 1.2 MeV Li+ ion beam is neutralized in a 1.6-meter drift compression section located after the last accelerator magnet. An 8-Tesla short focal length solenoid compresses the beam in the presence of the large volume plasma near the end of this section before the target. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including selected topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Here we describe the accelerator commissioning and time-resolved ionoluminescence measurements of yttrium aluminium perovskite using the fully integrated accel...

  12. Short intense ion pulses for materials and warm dense matter research

    Science.gov (United States)

    Seidl, Peter A.; Persaud, Arun; Waldron, William L.; Barnard, John J.; Davidson, Ronald C.; Friedman, Alex; Gilson, Erik P.; Greenway, Wayne G.; Grote, David P.; Kaganovich, Igor D.; Lidia, Steven M.; Stettler, Matthew; Takakuwa, Jeffrey H.; Schenkel, Thomas

    2015-11-01

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment-II at Lawrence Berkeley National Laboratory, by generating beam spots size with radius r<1 mm within 2 ns FWHM and approximately 1010 ions/pulse. To enable the short pulse durations and mm-scale focal spot radii, the 1.2 MeV Li+ ion beam is neutralized in a 1.6-meter drift compression section located after the last accelerator magnet. An 8-Tesla short focal length solenoid compresses the beam in the presence of the large volume plasma near the end of this section before the target. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including selected topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Here we describe the accelerator commissioning and time-resolved ionoluminescence measurements of yttrium aluminum perovskite using the fully integrated accelerator and neutralized drift compression components.

  13. Short intense ion pulses for materials and warm dense matter research

    Energy Technology Data Exchange (ETDEWEB)

    Seidl, Peter A., E-mail: PASeidl@lbl.gov [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Persaud, Arun; Waldron, William L. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Barnard, John J. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Davidson, Ronald C. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Friedman, Alex [Lawrence Livermore National Laboratory, Livermore, CA (United States); Gilson, Erik P. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Greenway, Wayne G. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Grote, David P. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Kaganovich, Igor D. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Lidia, Steven M.; Stettler, Matthew; Takakuwa, Jeffrey H.; Schenkel, Thomas [Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2015-11-11

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment-II at Lawrence Berkeley National Laboratory, by generating beam spots size with radius r<1 mm within 2 ns FWHM and approximately 10{sup 10} ions/pulse. To enable the short pulse durations and mm-scale focal spot radii, the 1.2 MeV Li{sup +} ion beam is neutralized in a 1.6-meter drift compression section located after the last accelerator magnet. An 8-Tesla short focal length solenoid compresses the beam in the presence of the large volume plasma near the end of this section before the target. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including selected topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Here we describe the accelerator commissioning and time-resolved ionoluminescence measurements of yttrium aluminum perovskite using the fully integrated accelerator and neutralized drift compression components.

  14. Betatron x-rays from laser plasma accelerators: a new probe for warm dense matter at LCLS

    Science.gov (United States)

    Albert, Felicie

    2016-10-01

    Betatron x-ray radiation, driven by electrons from laser-wakefield acceleration, has unique properties to probe high energy density (HED) plasmas and warm dense matter. Betatron radiation is produced when relativistic electrons oscillate in the plasma wake of a laser pulse. Its properties are similar to those of synchrotron radiation, with a 1000 fold shorter pulse. This presentation will focus on the experimental challenges and results related to the development of betatron radiation for x-ray absorption spectroscopy of HED matter at large-scale laser facilities. A detailed presentation of the source mechanisms and characteristics in the blowout regime of laser-wakefield acceleration will be followed by a description of recent experiments performed at the Linac Coherent Light Source (LCLS). At LCLS, we have recently commissioned the betatron x-ray source driven by the MEC short pulse laser (1 J, 40 fs). The source is used as a probe for investigating the X-ray absorption near edge structure (XANES) spectrum at the K- or L-edge of iron and silicon oxide driven to a warm dense matter state (temperature of a few eV and solid densities). The driver is either LCLS itself or an optical laser. These experiments demonstrate the capability to study the electron-ion equilibration mechanisms in warm dense matter with sub-picosecond resolution. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and supported by the Laboratory Directed research and development program under tracking codes 13-LW-076, 16-ERD-041 and by the Office of Fusion Energy Sciences under SCW1476 and SCW1569.

  15. Study of the Warm Dense Matter with XANES spectroscopy - Applications to planetary interiors

    Science.gov (United States)

    Denoeud, Adrien

    With the recent discovery of many exoplanets, modelling the interior of these celestial bodies is becoming a fascinating scientific challenge. In this context, it is crucial to accurately know the equations of state and the macroscopic and microscopic physical properties of their constituent materials in the Warm Dense Matter regime (WDM). Moreover, planetary models rely almost exclusively on physical properties obtained using first principles simulations based on density functional theory (DFT) predictions. It is thus of paramount importance to validate the basic underlying mechanisms occurring for key planetary constituents (metallization, dissociation, structural modifications, phase transitions, etc....) as pressure and temperature both increase. In this work, we were interested in two materials that can be mainly found in the Earth-like planets: silica, or SiO2, as a model compound of the silicates that constitute the major part of their mantles, and iron, which is found in abundance in their cores. These two materials were compressed and brought to the WDM regime by using strong shock created by laser pulses during various experiments performed on the LULI2000 (Palaiseau, France) and the JLF (Livermore, US) laser facilities and on the LCLS XFEL (Stanford, US). In order to penetrate this dense matter and to have access to its both ionic and electronic structures, we have probed silica and iron with time-resolved X-ray Absorption Near Edge Structure (XANES). In parallel with these experiments, we performed quantum molecular dynamics simulations based on DFT at conditions representative of the region investigated experimentally so as to extract the interesting physical processes and comprehend the limits of the implemented models. In particular, these works allowed us to highlight the metallization processes of silica in temperature and the structural changes of its liquid in density, as well as to more constrain the melting curve of iron at very high pressures.

  16. Optical conductivity of warm dense matter in wide frequency range within quantum statistical and kinetic approach

    CERN Document Server

    Veysman, M; Winkel, M; Reinholz, H

    2016-01-01

    Fundamental properties of warm dense matter are described by the dielectric function, which gives access to the frequency-dependent electrical conductivity, absorption, emission and scattering of radiation, charged particles stopping and further macroscopic properties. Different approaches to the dielectric function and the related dynamical collision frequency are compared in a wide frequency range. The high-frequency limit describing inverse bremsstrahlung and the low-frequency limit of the dc conductivity are considered. Sum rules and Kramers-Kronig relation are checked for the generalized linear response theory and the standard approach following kinetic theory. The results are discussed in application to aluminum, xenon and argon plasmas.

  17. Ion potential in warm dense matter: wake effects due to streaming degenerate electrons.

    Science.gov (United States)

    Moldabekov, Zhandos; Ludwig, Patrick; Bonitz, Michael; Ramazanov, Tlekkabul

    2015-02-01

    The effective dynamically screened potential of a classical ion in a stationary flowing quantum plasma at finite temperature is investigated. This is a key quantity for thermodynamics and transport of dense plasmas in the warm-dense-matter regime. This potential has been studied before within hydrodynamic approaches or based on the zero temperature Lindhard dielectric function. Here we extend the kinetic analysis by including the effects of finite temperature and of collisions based on the Mermin dielectric function. The resulting ion potential exhibits an oscillatory structure with attractive minima (wakes) and, thus, strongly deviates from the static Yukawa potential of equilibrium plasmas. This potential is analyzed in detail for high-density plasmas with values of the Brueckner parameter in the range 0.1≤r(s)≤1 for a broad range of plasma temperature and electron streaming velocity. It is shown that wake effects become weaker with increasing temperature of the electrons. Finally, we obtain the minimal electron streaming velocity for which attraction between ions occurs. This velocity turns out to be less than the electron Fermi velocity. Our results allow for reliable predictions of the strength of wake effects in nonequilibrium quantum plasmas with fast streaming electrons showing that these effects are crucial for transport under warm-dense-matter conditions, in particular for laser-matter interaction, electron-ion temperature equilibration, and stopping power.

  18. Pair potentials for warm dense matter and their application to x-ray Thomson scattering in aluminum and beryllium

    Science.gov (United States)

    Harbour, L.; Dharma-wardana, M. W. C.; Klug, D. D.; Lewis, L. J.

    2016-11-01

    Ultrafast laser experiments yield increasingly reliable data on warm dense matter, but their interpretation requires theoretical models. We employ an efficient density functional neutral-pseudoatom hypernetted-chain (NPA-HNC) model with accuracy comparable to ab initio simulations and which provides first-principles pseudopotentials and pair potentials for warm-dense matter. It avoids the use of (i) ad hoc core-repulsion models and (ii) "Yukawa screening" and (iii) need not assume ion-electron thermal equilibrium. Computations of the x-ray Thomson scattering (XRTS) spectra of aluminum and beryllium are compared with recent experiments and with density-functional-theory molecular-dynamics (DFT-MD) simulations. The NPA-HNC structure factors, compressibilities, phonons, and conductivities agree closely with DFT-MD results, while Yukawa screening gives misleading results. The analysis of the XRTS data for two of the experiments, using two-temperature quasi-equilibrium models, is supported by calculations of their temperature relaxation times.

  19. Importance of finite-temperature exchange correlation for warm dense matter calculations

    Science.gov (United States)

    Karasiev, Valentin V.; Calderín, Lázaro; Trickey, S. B.

    2016-06-01

    The effects of an explicit temperature dependence in the exchange correlation (XC) free-energy functional upon calculated properties of matter in the warm dense regime are investigated. The comparison is between the Karasiev-Sjostrom-Dufty-Trickey (KSDT) finite-temperature local-density approximation (TLDA) XC functional [Karasiev et al., Phys. Rev. Lett. 112, 076403 (2014), 10.1103/PhysRevLett.112.076403] parametrized from restricted path-integral Monte Carlo data on the homogeneous electron gas (HEG) and the conventional Monte Carlo parametrization ground-state LDA XC [Perdew-Zunger (PZ)] functional evaluated with T -dependent densities. Both Kohn-Sham (KS) and orbital-free density-functional theories are used, depending upon computational resource demands. Compared to the PZ functional, the KSDT functional generally lowers the dc electrical conductivity of low-density Al, yielding improved agreement with experiment. The greatest lowering is about 15% for T =15 kK. Correspondingly, the KS band structure of low-density fcc Al from the KSDT functional exhibits a clear increase in interband separation above the Fermi level compared to the PZ bands. In some density-temperature regimes, the deuterium equations of state obtained from the two XC functionals exhibit pressure differences as large as 4% and a 6% range of differences. However, the hydrogen principal Hugoniot is insensitive to the explicit XC T dependence because of cancellation between the energy and pressure-volume work difference terms in the Rankine-Hugoniot equation. Finally, the temperature at which the HEG becomes unstable is T ≥7200 K for the T -dependent XC, a result that the ground-state XC underestimates by about 1000 K.

  20. Thermal density functional theory, ensemble density functional theory, and potential functional theory for warm dense matter

    Science.gov (United States)

    Pribram-Jones, Aurora

    Warm dense matter (WDM) is a high energy phase between solids and plasmas, with characteristics of both. It is present in the centers of giant planets, within the earth's core, and on the path to ignition of inertial confinement fusion. The high temperatures and pressures of warm dense matter lead to complications in its simulation, as both classical and quantum effects must be included. One of the most successful simulation methods is density functional theory-molecular dynamics (DFT-MD). Despite great success in a diverse array of applications, DFT-MD remains computationally expensive and it neglects the explicit temperature dependence of electron-electron interactions known to exist within exact DFT. Finite-temperature density functional theory (FT DFT) is an extension of the wildly successful ground-state DFT formalism via thermal ensembles, broadening its quantum mechanical treatment of electrons to include systems at non-zero temperatures. Exact mathematical conditions have been used to predict the behavior of approximations in limiting conditions and to connect FT DFT to the ground-state theory. An introduction to FT DFT is given within the context of ensemble DFT and the larger field of DFT is discussed for context. Ensemble DFT is used to describe ensembles of ground-state and excited systems. Exact conditions in ensemble DFT and the performance of approximations depend on ensemble weights. Using an inversion method, exact Kohn-Sham ensemble potentials are found and compared to approximations. The symmetry eigenstate Hartree-exchange approximation is in good agreement with exact calculations because of its inclusion of an ensemble derivative discontinuity. Since ensemble weights in FT DFT are temperature-dependent Fermi weights, this insight may help develop approximations well-suited to both ground-state and FT DFT. A novel, highly efficient approach to free energy calculations, finite-temperature potential functional theory, is derived, which has the

  1. Calculations on the stopping power of a heterogeneous Warm Dense Matter

    CERN Document Server

    Casas, David; Schnürer, Matthias; Barriga-Carrasco, Manuel D; Morales, Roberto; González-Gallego, Luis

    2015-01-01

    The stopping power of Warm Dense Matter (WDM) is estimated by means of the individual contributions of free electrons and bound electrons existing in this special kind of matter, located between classical and degenerate plasmas. For free electrons, the dielectric formalism, well described in previous works of our research group, is used to estimate free electron stopping power. For bound electrons, mean excitation energy of ions is used. Excitation energies are obtained through atomic calculations of the whole atom or, shell by shell in order to estimate their stopping power. Influence of temperature and density is analyzed in case of an impinging projectile. This influence became important for low projectile velocities and negligible for high ones. Using both analysis, the stopping power of an extended WDM is inferred from a dynamical calculation of energy transferred from the projectile to the plasma, where the Bragg peak and stopping range are calculated. Finally, this theoretical framework is used to stud...

  2. The ion potential in warm dense matter: wake effects due to streaming degenerate electrons

    CERN Document Server

    Moldabekov, Zhandos; Bonitz, Michael; Ramazano, Tlekkabul

    2014-01-01

    The effective dynamically screened potential of a classical ion in a stationary flowing quantum plasma at finite temperature is investigated. This is a key quantity for thermodynamics and transport of dense plasmas in the warm dense matter regime. To compute this potential a linear response description of the electrons via the Mermin dielectric function is utilized with electron-electron collisions taken into account via a relaxation time approximation. The ion potential strongly deviates from the static Yukawa potential exhibiting the familiar oscillatory structure with attractive minima (wake potential). This potential is analyzed in detail for high-density plasmas with values of the Brueckner parameter in the range $0.1 \\le r_s \\le 1$, for a broad range of plasma temperature and electron streaming velocity. It is shown that wake effects become weaker with increasing temperature of the electrons. Finally, we obtain the minimal electron streaming velocity for which attraction between ions occurs. This veloci...

  3. Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Warm Dense Matter

    Science.gov (United States)

    Militzer, Burkhard; Driver, Kevin

    2011-10-01

    We analyze the applicability of two first-principles simulation techniques, path integral Monte Carlo (PIMC) and density functional molecular dynamics (DFT-MD), to study the regime of warm dense matter. We discuss the advantages as well as the limitations of each method and propose directions for future development. Results for dense, liquid helium, where both methods have been applied, demonstrate the range of each method's applicability. Comparison of the equations of state from simulations with analytical theories and free energy models show that DFT is useful for temperatures below 100000 K and then PIMC provides accurate results for all higher temperatures. We characterize the structure of the liquid in terms of pair correlation functions and study the closure of the band gap with increasing density and temperature. Finally, we discuss simulations of heavier elements and demonstrate the reliability are both methods in such cases with preliminary results.

  4. Input energy measurement toward warm dense matter generation using intense pulsed power generator

    Science.gov (United States)

    Hayashi, R.; Ito, T.; Ishitani, T.; Tamura, F.; Kudo, T.; Takakura, N.; Kashine, K.; Takahashi, K.; Sasaki, T.; Kikuchi, T.; Harada, Nob.; Jiang, W.; Tokuchi, A.

    2016-05-01

    In order to investigate properties of warm dense matter (WDM) in inertial confinement fusion (ICF), evaluation method for the WDM with isochoric heating on the implosion time-scale using an intense pulsed power generator ETIGO-II (∼1 TW, ∼50 ns) has been considered. In this study, the history of input energy into the sample is measured from the voltage and the current waveforms. To achieve isochoric heating, a foamed aluminum with pore sizes 600 μm and with 90% porosity was packed into a hollow glass capillary (ø 5 mm × 10 mm). The temperature of the sample is calculated from the numerical calculation using the measured input power. According to the above measurements, the input energy into a sample and the achievable temperature are estimated to be 300 J and 6000 K. It indicates that the WDM state is generated using the proposed method with ICF implosion time-scale.

  5. Accelerator and Ion Beam Tradeoffs for Studies of Warm Dense Matter

    CERN Document Server

    Barnard, John J; Callahan, Debra; Davidson, Ronald C; Friedman, Alex; Grant-Logan, B; Grisham, Larry; Lee, Edward; Lee, Richard; Olson, Craig; Rose, David; Santhanam, Parthiban; Sessler, Andrew M; Staples, John W; Tabak, Max; Welch, Dale; Wurtele, Jonathan; Yu, Simon

    2005-01-01

    One approach to heat a target to "Warm Dense Matter" conditions (similar, for example, to the interiors of giant planets or certain stages in Inertial Confinement Fusion targets), is to use intense ion beams as the heating source. By consideration of ion beam phase space constraints, both at the injector, and at the final focus, and consideration of simple equations of state, approximate conditions at a target foil may be calculated. Thus target temperature and pressure may be calculated as a function of ion mass, ion energy, pulse duration, velocity tilt, and other accelerator parameters. We examine the variation in target performance as a function of various beam and accelerator parameters, in the context of several different accelerator concepts, recently proposed for WDM studies.

  6. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Mo, M. Z., E-mail: mmo09@slac.stanford.edu; Shen, X.; Chen, Z.; Li, R. K.; Dunning, M.; Zheng, Q.; Weathersby, S. P.; Reid, A. H.; Coffee, R.; Makasyuk, I.; Edstrom, S.; McCormick, D.; Jobe, K.; Hast, C.; Glenzer, S. H.; Wang, X. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Sokolowski-Tinten, K. [Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, D-47048 Duisburg (Germany)

    2016-11-15

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 μm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined. This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime.

  7. Restricted Path-Integral Molecular Dynamics for Simulating the Correlated Electron Plasma in Warm Dense Matter

    Science.gov (United States)

    Kapila, Vivek; Deymier, Pierre; Runge, Keith

    2011-10-01

    Several areas of study including heavy ion beam, large scale laser, and high pressure or Thomson scattering studies necessitate a fundamental understanding of warm dense matter (WDM) i.e. matter at high temperature and high density. The WDM regime, however, lacks any adequate highly developed class of simulation methods. Recent progress to address this deficit has been the development of orbital-free Density Functional Theory (ofDFT). However, scant benchmark information is available on temperature and pressure dependence of simple but realistic models in WDM regime. The present work aims to fill this critical gap using the restricted path-integral molecular dynamics (rPIMD) method. Within the discrete path integral representation, electrons are described as harmonic necklaces. Quantum exchange takes the form of cross linking between electron necklaces. The fermion sign problem is addressed by restricting the density matrix to positive values. The molecular dynamics algorithm is employed to sample phase space. Here, we focus on the behavior of strongly correlated electron plasmas under WDM conditions. We compute the kinetic and potential energies and compare them to those obtained with the ofDFT method. Several areas of study including heavy ion beam, large scale laser, and high pressure or Thomson scattering studies necessitate a fundamental understanding of warm dense matter (WDM) i.e. matter at high temperature and high density. The WDM regime, however, lacks any adequate highly developed class of simulation methods. Recent progress to address this deficit has been the development of orbital-free Density Functional Theory (ofDFT). However, scant benchmark information is available on temperature and pressure dependence of simple but realistic models in WDM regime. The present work aims to fill this critical gap using the restricted path-integral molecular dynamics (rPIMD) method. Within the discrete path integral representation, electrons are described as

  8. Theory of complex fluids in the warm-dense-matter regime, and application to phase-transitions in liquid carbon

    CERN Document Server

    Dharma-wardana, M W C

    2016-01-01

    Using data from recent laser-shock experiments and related density-functional molecular-dynamics simulations on carbon, we demonstrate that the ionic structures predicted within the neutral-pseudo-atom approach for a complex liquid in the warm-dense matter regime are in good agreement with available data, even where transient covalent bonding dominates ionic correlations. Evidence for an unusual phase transition of a liquid $\\to$ vapor with an abrupt decrease in ionization occurring simultaneously is presented. Here a covalently-bonded metallic-liquid, i.e., carbon of density 1.0 g/cm$^3$, transits to a disordered mono-atomic fluid at 7 eV. Other transitions where the mean ionization $Z$ drops abruptly are also uncovered

  9. The generation of warm dense matter samples using pulsed-power generators

    Science.gov (United States)

    Gourdain, P. A.; Seyler, C. E.; Knapp, P. F.

    2016-10-01

    Warm dense matter (WDM) bridges the gap between plasma and condensed matter, with densities similar to that of a solid, but temperature on the order of 1 eV. WDM is key to understanding the formation of gaseous giants, Mega-Earths, planetary collisions and inertial fusion implosions. Yet, the quantum properties of WDM and how they are expressed at the macroscopic level are mostly unknown. This paper uses 3-dimensional numerical simulations to show that cm-scale WDM samples can be generated by pulsed-power machines using a fast plasma closing switch, which virtually eliminates the mixing of WDM with other states of matter, allowing the measurement of its physical properties using line average diagnostics. A pre-ionized gas puff is imploded onto a central metal rod. Initially, most of the discharge current flows inside the gas shell. When the shell reaches the rod the full current switches to the rod in less than 10 ns. The subsequent compression produces WDM. We will discuss how an existing platform to generate cm-scale WDM at 20MA on the Z-machine at Sandia National Laboratories. This research is sponsored by DOE.

  10. Atomistic study of mixing at high Z / low Z interfaces at Warm Dense Matter Conditions

    Science.gov (United States)

    Haxhimali, Tomorr; Glosli, James; Rudd, Robert; Lawrence Livermore National Laboratory Team

    2016-10-01

    We use atomistic simulations to study different aspects of mixing occurring at an initially sharp interface of high Z and low Z plasmas in the Warm/Hot Dense Matter regime. We consider a system of Diamond (the low Z component) in contact with Ag (the high Z component), which undergoes rapid isochoric heating from room temperature up to 10 eV, rapidly changing the solids into warm dense matter at solid density. We simulate the motion of ions via the screened Coulomb potential. The electric field, the electron density and ionizations level are computed on the fly by solving Poisson equation. The spatially varying screening lengths computed from the electron cloud are included in this effective interaction; the electrons are not simulated explicitly. We compute the electric field generated at the Ag-C interface as well as the dynamics of the ions during the mixing process occurring at the plasma interface. Preliminary results indicate an anomalous transport of high Z ions (Ag) into the low Z component (C); a phenomenon that is partially related to the enhanced transport of ions due to the generated electric field. These results are in agreement with recent experimental observation on Au-diamond plasma interface. This work was performed under the auspices of the US Dept. of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344.

  11. Quantum molecular dynamics study of expanded beryllium: evolution from warm dense matter to atomic fluid.

    Science.gov (United States)

    Li, Dafang; Liu, Haitao; Zeng, Siliang; Wang, Cong; Wu, Zeqing; Zhang, Ping; Yan, Jun

    2014-07-31

    By performing quantum molecular dynamics (QMD) simulations, we investigate the equation of states, electrical and optical properties of the expanded beryllium at densities two to one-hundred lower than the normal solid density, and temperatures ranging from 5000 to 30000 K. With decreasing the density of Be, the optical response evolves from the one characteristic of a simple metal to the one of an atomic fluid. By fitting the optical conductivity spectra with the Drude-Smith model, it is found that the conducting electrons become localized at lower densities. In addition, the negative derivative of the electrical resistivity on temperature at density about eight lower than the normal solid density demonstrates that the metal to nonmetal transition takes place in the expanded Be. To interpret this transition, the electronic density of states is analyzed systematically. Furthermore, a direct comparison of the Rosseland opacity obtained by using QMD and the standard opacity code demonstrates that QMD provides a powerful tool to validate plasma models used in atomic physics approaches in the warm dense matter regime.

  12. Generation and characterization of warm dense matter isochorically heated by laser-induced relativistic electrons in a wire target

    Science.gov (United States)

    Schönlein, A.; Boutoux, G.; Pikuz, S.; Antonelli, L.; Batani, D.; Debayle, A.; Franz, A.; Giuffrida, L.; Honrubia, J. J.; Jacoby, J.; Khaghani, D.; Neumayer, P.; Rosmej, O. N.; Sakaki, T.; Santos, J. J.; Sauteray, A.

    2016-05-01

    We studied the interaction of a high-intensity laser with mass-limited Ti-wires. The laser was focused up to 7× 1020 \\text{W/cm}2 , with contrast of 10-10 to produce relativistic electrons. High-spatial-resolution X-ray spectroscopy was used to measure isochoric heating induced by hot electrons propagating along the wire up to 1 mm depth. For the first time it was possible to distinguish surface target regions heated by mixed plasma mechanisms from those heated only by the hot electrons that generate warm dense matter with temperatures up to 50 eV. Our results are compared to simulations that highlight both the role of electron confinement inside the wire and the importance of resistive stopping powers in warm dense matter.

  13. Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Q., E-mail: qji@lbl.gov; Seidl, P. A.; Waldron, W. L.; Takakuwa, J. H.; Persaud, A.; Schenkel, T. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Friedman, A.; Grote, D. P.; Barnard, J. J. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-02-15

    The neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ∼1 eV using intense, short pulses (∼1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He{sup +} ions leads to more uniform energy deposition of the target material than Li{sup +} ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li{sup +} ions from a hot plate type ion source. He{sup +} beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. The accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.

  14. Pump-probe studies of radiation induced defects and formation of warm dense matter with pulsed ion beams

    Science.gov (United States)

    Schenkel, T.; Persaud, A.; Gua, H.; Seidl, P. A.; Waldron, W. L.; Gilson, E. P.; Kaganovich, I. D.; Davidson, R. C.; Friedman, A.; Barnard, J. J.; Minior, A. M.

    2014-10-01

    We report results from the 2nd generation Neutralized Drift Compression Experiment at Berkeley Lab. NDCX-II is a pulsed, linear induction accelerator designed to drive thin foils to warm dense matter (WDM) states with peak temperatures of ~ 1 eV using intense, short pulses of 1.2 MeV lithium ions. Tunability of the ion beam enables pump-probe studies of radiation effects in solids as a function of excitation density, from isolated collision cascades to the onset of phase-transitions and WDM. Ion channeling is an in situ diagnostic of damage evolution during ion pulses with a sensitivity of channeled ions tracks lattice disorder evolution with a resolution of ~ 1 ns using fast current measurements. We will discuss pump-probe experiments with pulsed ion beams and the development of diagnostics for WDM and multi-scale (ms to fs) access to the materials physics of collision cascades e.g. in fusion reactor materials. Work performed under auspices of the US DOE under Contract No. DE-AC02-05CH11231.

  15. A single-shot spatial chirp method for measuring initial AC conductivity evolution of femtosecond laser pulse excited warm dense matter

    Science.gov (United States)

    Chen, Z.; Hering, P.; Brown, S. B.; Curry, C.; Tsui, Y. Y.; Glenzer, S. H.

    2016-11-01

    To study the rapid evolution of AC conductivity from ultrafast laser excited warm dense matter (WDM), a spatial chirp single-shot method is developed utilizing a crossing angle pump-probe configuration. The pump beam is shaped individually in two spatial dimensions so that it can provide both sufficient laser intensity to excite the material to warm dense matter state and a uniform time window of up to 1 ps with sub-100 fs FWHM temporal resolution. Temporal evolution of AC conductivity in laser excited warm dense gold was also measured.

  16. Visualizing expanding warm dense matter heated by laser-generated ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Woosuk [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-24

    This PowerPoint presentation concluded with the following. We calculated the expected heating per atom and temperatures of various target materials using a Monte Carlo simulation code and SESAME EOS tables. We used aluminum ion beams to heat gold and diamond uniformly and isochorically. A streak camera imaged the expansion of warm dense gold (5.5 eV) and diamond (1.7 eV). GXI-X recorded all 16 x-ray images of the unheated gold bar targets proving that it could image the motion of the gold/diamond interface of the proposed target.

  17. Optical conductivity of warm dense matter within a wide frequency range using quantum statistical and kinetic approaches

    Science.gov (United States)

    Veysman, M.; Röpke, G.; Winkel, M.; Reinholz, H.

    2016-07-01

    Fundamental properties of warm dense matter are described by the dielectric function, which gives access to the frequency-dependent electrical conductivity; absorption, emission, and scattering of radiation; charged particles stopping; and further macroscopic properties. Different approaches to the dielectric function and the related dynamical collision frequency are compared in a wide frequency range. The high-frequency limit describing inverse bremsstrahlung and the low-frequency limit of the dc conductivity are considered. Sum rules and Kramers-Kronig relation are checked for the generalized linear response theory and the standard approach following kinetic theory. The results are discussed in application to aluminum, xenon, and argon plasmas.

  18. Unified first principles description from warm dense matter to ideal ionized gas plasma: electron-ion collisions induced friction.

    Science.gov (United States)

    Dai, Jiayu; Hou, Yong; Yuan, Jianmin

    2010-06-18

    Electron-ion interactions are central to numerous phenomena in the warm dense matter (WDM) regime and at higher temperature. The electron-ion collisions induced friction at high temperature is introduced in the procedure of ab initio molecular dynamics using the Langevin equation based on density functional theory. In this framework, as a test for Fe and H up to 1000 eV, the equation of state and the transition of electronic structures of the materials with very wide density and temperature can be described, which covers a full range of WDM up to high energy density physics. A unified first principles description from condensed matter to ideal ionized gas plasma is constructed.

  19. Analysis of laser shock experiments on precompressed samples using a quartz reference and application to warm dense hydrogen and helium

    CERN Document Server

    Brygoo, Stephanie; Loubeyre, Paul; Lazicki, Amy E; Hamel, Sebastien; Qi, Tingting; Celliers, Peter M; Coppari, Federica; Eggert, Jon H; Fratanduono, Dayne E; Hicks, Damien G; Rygg, J Ryan; Smith, Raymond F; Swift, Damian C; Collins, Gilbert W; Jeanloz, Raymond

    2015-01-01

    Megabar (1 Mbar = 100 GPa) laser shocks on precompressed samples allow reaching unprecedented high densities and moderately high 10000-100000K temperatures. We describe here a complete analysis framework for the velocimetry (VISAR) and pyrometry (SOP) data produced in these experiments. Since the precompression increases the initial density of both the sample of interest and the quartz reference for pressure-density, reflectivity and temperature measurements, we describe analytical corrections based on available experimental data on warm dense silica and density-functional-theory based molecular dynamics computer simulations. Using our improved analysis framework we report a re-analysis of previously published data on warm dense hydrogen and helium, compare the newly inferred pressure, density and temperature data with most advanced equation of state models and provide updated reflectivity values.

  20. Monte-Carlo approach to calculate the ionization of warm dense matter within particle-in-cell simulations

    CERN Document Server

    Wu, D; Yu, W; Fritzsche, S

    2016-01-01

    A physical model based on Monte-Carlo approach is proposed to calculate the ionization dynamics of warm dense matters within particle-in-cell simulations, where impact ionization, electron-ion recombination and ionization potential depression (IPD) by surrounding plasmas are taken into consideration self-consistently. When compared with other models, which are applied in the literature for plasmas near thermal equilibrium, the temporal relaxation of ionizations can also be simulated by the proposed model with the final thermal equilibrium determined by the competition between impact ionization and its inverse process, i.e., electron-ion recombination. Our model is general and can be applied for both single elements and alloys with quite different compositions. The proposed model is implemented into a particle-in-cell (PIC) simulation code, and the average ionization degree of bulk aluminium varying with temperature is calculated, showing good agreement with the data provided by FLYCHK code.

  1. Very low electron temperature in warm dense matter formed by focused picosecond soft x-ray laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Ishino, Masahiko, E-mail: ishino.masahiko@jaea.go.jp; Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Yamagiwa, Mitsuru [Quantum Beam Science Center, Japan Atomic Energy Agency, 8-1-7, Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Pikuz, Tatiana [Joint Institute for High Temperatures, Russian Academy of Sciences, 13-2, Izhorskaya Street, Moscow 125412 (Russian Federation); Graduate School of Engineering, Osaka University, 1-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Skobelev, Igor [Joint Institute for High Temperatures, Russian Academy of Sciences, 13-2, Izhorskaya Street, Moscow 125412 (Russian Federation); National Research Nuclear University, Moscow Engineering Physics Institute, 31, Kashirskoe Shosse, Moscow 115409 (Russian Federation); Faenov, Anatoly [Joint Institute for High Temperatures, Russian Academy of Sciences, 13-2, Izhorskaya Street, Moscow 125412 (Russian Federation); Institute for Academic Initiatives, Osaka University, 1-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Inogamov, Nail [Landau Institute for Theoretical Physics, Russian Academy of Sciences, 1-A, Akademika Semenova av., Chernogolovka, Moscow Region 142432 (Russian Federation)

    2014-11-14

    We investigated the optical emission from the ablating surfaces induced by the irradiations of soft x-ray laser (SXRL) pulses with the aim of estimation of the maximum electron temperature. No emission signal in the spectral range of 400–800 nm could be observed despite the formation of damage structures on the target surfaces. Hence, we estimated an upper limit for the electron temperature of 0.4–0.7 eV for the process duration of 100–1000 ps. Our results imply that the ablation and/or surface modification by the SXRL is not accompanied by plasma formation but is induced by thermo-mechanical pressure, which is so called a spallative ablation. This spallative ablation process occurs in the low electron temperature region of a non-equilibrium state of warm dense matter.

  2. The impact of three dimensional MHD instabilities on the generation of warm dense matter using a MA-class linear transformer driver

    Science.gov (United States)

    Gourdain, P.-A.; Seyler, C. E.

    2017-09-01

    Warm dense matter is difficult to generate since it corresponds to a state of matter which pressure is order of magnitude larger than can be handled by natural materials. A diamond anvil can be used to pressurize matter up to one Gbar, this matter is at high density but at room temperature. High power lasers and heavy ion beams can generate warm dense matter on time scales where measuring quasi-static transport coefficients such as viscosity or heat conduction proves difficult since both experimental techniques relies on inertial confinement. We present here a third method to generate warm dense matter. It uses a pulsed-power driver which current rise time is substantially shortened by using a plasma opening switch, limiting the development of electrothermal instabilities. The switch relies on the implosion of a gas puff Z-pinch which carries most of the discharge current until the pinch reaches the sample. After that, the sample is compressed until it reaches the warm dense matter regime. Three-dimensional magnetohydrodynamics computations show that if the density of the gas is low enough no detectable instabilities (e.g. kinks and sausages modes) impede the remainder of the implosion.

  3. Probing warm dense lithium by inelastic X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Saiz, E.; Riley, D. [School of Mathematics and Physics, Queen' s University of Belfast, Belfast (United Kingdom); Gregori, G. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford (United Kingdom); Gregori, G.; Clarke, R.J.; Neely, D.; Notley, M.M.; Spindloe, C. [Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX (United Kingdom); Gericke, D.O.; Vorberger, J.; Wunsch, K. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry (United Kingdom); Barbrel, B.; Koenig, M. [Laboratoire pour l' Utilisation des Laser Intenses, Ecole Polytechnique - Universite Paris-6, 91 - Palaiseau (France); Freeman, R.R.; Weber, R.L.; Van Woerkom, L. [Department of Physics, The Ohio State University, Columbus, Ohio (United States); Glenzer, S.H.; Landen, O.L.; Neumayer, P.; Price, D. [Lawrence Livermore National Laboratory, Livermore, California (United States); Khattak, F.Y. [Department of Physics, Kohat University of Science and Technology, Kohat-26000, NWFP (Pakistan); Pelka, A.; Roth, M.; Schollmeier, M. [Institut fur Kernphysik, Technische Universitat Darmstadt (Germany)

    2008-10-15

    One of the grand challenges of contemporary physics is understanding strongly interacting quantum systems comprising such diverse examples as ultracold atoms in traps, electrons in high-temperature superconductors and nuclear matter. Warm dense matter, defined by temperatures of a few electron volts and densities comparable with solids, is a complex state of such interacting matter. Moreover, the study of warm dense matter states has practical applications for controlled thermonuclear fusion, where it is encountered during the implosion phase, and it also represents laboratory analogues of astrophysical environments found in the core of planets and the crusts of old stars. Here we demonstrate how warm dense matter states can be diagnosed and structural properties can be obtained by inelastic X-ray scattering measurements on a compressed lithium sample. Combining experiments and ab initio simulations enables us to determine its microscopic state and to evaluate more approximate theoretical models for the ionic structure. (authors)

  4. Monte-Carlo approach to calculate the proton stopping in warm dense matter within particle-in-cell simulations

    CERN Document Server

    Wu, D; Yu, W; Fritzsche, S

    2016-01-01

    A Monte-Carlo approach to proton stopping in warm dense matter is implemented into an existing particle-in-cell code. The model is based on multiple binary-collisions among electron-electron, electron-ion and ion-ion, taking into account contributions from both free and bound electrons, and allows to calculate particle stopping in much more natural manner. At low temperature limit, when ``all'' electron are bounded at the nucleus, the stopping power converges to the predictions of Bethe-Bloch theory, which shows good consistency with data provided by the NIST. With the rising of temperatures, more and more bound electron are ionized, thus giving rise to an increased stopping power to cold matter, which is consistent with the report of a recently experimental measurement [Phys. Rev. Lett. 114, 215002 (2015)]. When temperature is further increased, with ionizations reaching the maximum, lowered stopping power is observed, which is due to the suppression of collision frequency between projected proton beam and h...

  5. Electron transport calculations in warm dense matter using scattering cross sections

    CERN Document Server

    Burrill, D J; Charest, M R J; Starrett, C E

    2015-01-01

    The Ziman formulation of electrical conductivity is tested in warm and hot dense matter using the pseudo-atom molecular dynamics method. Several implementation options that have been widely used in the literature are systematically tested through a comparison to accurate but expensive Kohn-Sham density functional theory molecular dynamics (KS-DFT-MD) calculations. The comparison is made for several elements and mixtures and for a wide range of temperatures and densities, and reveals a preferred method that generally gives very good agreement with the KSDFT-MD results, but at a fraction of the computational cost.

  6. Simulation of the Correlated Electron Plasma in the Warm Dense Matter Regime by Restricted Path-Integral Molecular Dynamics

    Science.gov (United States)

    Kapila, Vivek; Deymier, Pierre; Runge, Keith

    2012-02-01

    Warm dense matter (WDM) can be characterized by electron temperatures of a few eV and densities an order of magnitude or more beyond ambient. This regime currently lacks any adequate highly developed class of simulation methods. Recent developments in orbital-free Density Functional Theory (ofDFT) aim to provide such a simulation method, however, little benchmark information is available on temperature and pressure dependence of simple but realistic models in WDM regime. The present work aims to fill this critical gap using the restricted path-integral molecular dynamics (rPIMD) method. Within the discrete path integral representation, electrons are described as harmonic necklaces, while, quantum exchange takes the form of cross linking between electron necklaces. The fermion sign problem is addressed by restricting the density matrix to positive values and a molecular dynamics algorithm is employed to sample phase space. Here, we focus on the behavior of strongly correlated electron plasmas under WDM conditions. We compute the kinetic and potential energies and compare them to those obtained with the ofDFT method.

  7. Monte Carlo approach to calculate proton stopping in warm dense matter within particle-in-cell simulations

    Science.gov (United States)

    Wu, D.; He, X. T.; Yu, W.; Fritzsche, S.

    2017-02-01

    A Monte Carlo approach to proton stopping in warm dense matter is implemented into an existing particle-in-cell code. This approach is based on multiple electron-electron, electron-ion, and ion-ion binary collision and accounts for both the free and the bound electrons in the plasmas. This approach enables one to calculate the stopping of particles in a more natural manner than existing theoretical treatment. In the low-temperature limit, when "all" electrons are bound to the nucleus, the stopping power coincides with the predictions from the Bethe-Bloch formula and is consistent with the data from the National Institute of Standard and Technology database. At higher temperatures, some of the bound electrons are ionized, and this increases the stopping power in the plasmas, as demonstrated by A. B. Zylstra et al. [Phys. Rev. Lett. 114, 215002 (2015)], 10.1103/PhysRevLett.114.215002. At even higher temperatures, the degree of ionization reaches a maximum and thus decreases the stopping power due to the suppression of collision frequency between projected proton beam and hot plasmas in the target.

  8. Bayesian inference of x-ray diffraction spectra from warm dense matter with the one-component-plasma model

    Science.gov (United States)

    Clérouin, Jean; Desbiens, Nicolas; Dubois, Vincent; Arnault, Philippe

    2016-12-01

    We show that the Bayesian inference of recently measured x-ray diffraction spectra from laser-shocked aluminum [L. B. Fletcher et al., Nat. Photon. 9, 274 (2015), 10.1038/nphoton.2015.41] with the one-component-plasma (OCP) model performs remarkably well at estimating the ionic density and temperature. This statistical approach requires many evaluations of the OCP static structure factor, which were done using a recently derived analytic fit. The atomic form factor is approximated by an exponential function in the diffraction window of the first peak. The electronic temperature is then estimated from a comparison of this approximated form factor with the electronic structure of an average atom model. Out-of-equilibrium states, with electrons hotter than ions, are diagnosed for the spectra obtained early after the pump, whereas at a late time delay the plasma is at thermal equilibrium. Apart from the present findings, this OCP-based modeling of warm dense matter has an important role to play in the interpretation of x-ray Thomson scattering measurements currently performed at large laser facilities.

  9. Warm dense crystallography

    Science.gov (United States)

    Valenza, Ryan A.; Seidler, Gerald T.

    2016-03-01

    The intense femtosecond-scale pulses from x-ray free electron lasers (XFELs) are able to create and interrogate interesting states of matter characterized by long-lived nonequilibrium semicore or core electron occupancies or by the heating of dense phases via the relaxation cascade initiated by the photoelectric effect. We address here the latter case of "warm dense matter" (WDM) and investigate the observable consequences of x-ray heating of the electronic degrees of freedom in crystalline systems. We report temperature-dependent density functional theory calculations for the x-ray diffraction from crystalline LiF, graphite, diamond, and Be. We find testable, strong signatures of condensed-phase effects that emphasize the importance of wide-angle scattering to study nonequilibrium states. These results also suggest that the reorganization of the valence electron density at eV-scale temperatures presents a confounding factor to achieving atomic resolution in macromolecular serial femtosecond crystallography (SFX) studies at XFELs, as performed under the "diffract before destroy" paradigm.

  10. Density functional theory approach for calculation of dielectric properties of warm dense matter

    Science.gov (United States)

    Saitov, Ilnur

    2015-06-01

    The reflectivity of shocked xenon was measured in the experiments of Mintsev and Zaporoghets for wavelength 1064 nm. But there is no adequate theoretical explanation of these reflectivity results in the framework of the standard methods of nonideal plasma theory. The assumption of significant width to the shock front gives a good agreement with the experimental data. However, there are no evidences of this effect in the experiment. Reflectivity of shocked compressed xenon plasma is calculated in the framework of the density functional theory approach as in. Dependencies on the frequency of incident radiation and on the plasma density are analyzed. The Fresnel formula for the reflectivity is used. The longitudinal expression in the long wavelength limit is applied for the calculation of the imaginary part of the dielectric function. The real part of the dielectric function is calculated by means of the Kramers-Kronig transformation. The approach for the calculation of plasma frequency is developed.

  11. OSIRIS Modeling of High Energy Electron Transport in Warm Dense Matter

    Science.gov (United States)

    May, J.; Yabuuchi, T.; McGuffey, C.; Wei, Ms; Beg, F.; Mori, Wb

    2016-10-01

    In experiments on the Omega EP laser, a high intensity laser beam (eA /me c > 1) is focused onto a gold foil, generating relativistic electrons. Behind the Au foil is a layer of plastic foam through which the electrons are allowed to transport, and on the far side of the CH from the gold is a copper foil; electron fluence is measured by recording the k- α from that foil. The foam layer is either pre-ionized via a shock launched from an ablator irradiated earlier with a beam perpendicular to the high intensity beam; or the foam is in the solid state when the high intensity beam is switched on. In the latter case the foam - which has an initial density of 200mg /cm3 - heats to a temperature of 40eV and rarifies to a density of 30mg /cm3 . Results show an order of magnitude decrease in k- α when the CH layer is pre-ionized compared to cold CH. OSIRIS simulations indicate that the primary explanation for the difference in transport seen in the experiment is the partial resistive collimation of the beam in the higher density material, caused by collisional resistivity. The effect seems to be mostly caused by the higher density itself, with temperature having minimal effect. The authors acknowledge the support of the Department of Energy under contract DE-NA 0001833 and the National Science Foundation under contract ACI 1339893.

  12. Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter.

    Science.gov (United States)

    Johnson, W R; Nilsen, J

    2016-03-01

    The influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity and also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.

  13. Electron-ion and ion-ion potentials for modeling warm-dense-matter: applications to laser-heated or shock-compressed Al and Si

    CERN Document Server

    Dharma-wardana, M W C

    2012-01-01

    The pair-interactions U_{ij}(r) determine the thermodynamics and linear transport properties of matter via the pair-distribution functions (PDFs), i.e., g_{ij}(r). Great simplicity is achieved if U_{ij}(r) could be directly used to predict material properties via classical simulations, avoiding many-body wavefunctions. Warm dense matter (WDM) is encountered in quasi-equilibria where the electron temperature $T_e$ differs from the ion temperature T_i, as in laser-heated or in shock-compressed matter. The electron PDFs g_{ee}(r) as perturbed by the ions are used to evaluate fully non-local exchange-correlation corrections to the free energy, using Hydrogen as an example. Electron-ion potentials for ions with a bound core are discussed with Al and Si as examples, for WDM with T_e \

  14. Average-atom model for two-temperature states and ionic transport properties of aluminum in the warm dense matter regime

    Science.gov (United States)

    Hou, Yong; Fu, Yongsheng; Bredow, Richard; Kang, Dongdong; Redmer, Ronald; Yuan, Jianmin

    2017-03-01

    The average-atom model combined with the hyper-netted chain approximation is an efficient tool for electronic and ionic structure calculations for warm dense matter. Here we generalize this method in order to describe non-equilibrium states with different electron and ion temperature as produced in laser-matter interactions on ultra-short time scales. In particular, the electron-ion and ion-ion correlation effects are considered when calculating the electron structure. We derive an effective ion-ion pair-potential using the electron densities in the framework of temperature-depended density functional theory. Using this ion-ion potential we perform molecular dynamics simulations in order to determine the ionic transport properties such as the ionic diffusion coefficient and the shear viscosity through the ionic velocity autocorrelation functions.

  15. Semi-analytical calculations for parameters of boiling layer in isetropic expansion of warm dense matter with van der Waals equation of state

    CERN Document Server

    Borovikov, Dmitry

    2012-01-01

    Features and parameters of \\boiling" liquid layer, which arises under conditions of isentropic expansion of warm dense matter (WDM), are stud- ied with the use of simplest van der Waals equation of state (EOS). Advan- tage of this EOS is possibility of demonstrable and semi-analytical descrip- tion of thermo- and hydrodynamics of the process. Idealized self-similar case of behavior of matter on interception of equilibrium (not metastable) isoentropic curve and boundary of gas-liquid coexistence curve (binodal) is analyzed. The possibility of formation of such "liquid layer" was studied previously in [1] during solving the problem of ablation of metal surface under the action of strong laser radiation. Peculiarity of such "freezing" of finite portion of expanding matter in the state, which corresponds to the binodal of gas-liquid or/and other phase transitions|so called "phase freezeout"and prospects of applications of this phenomenon for intended generation of uniform and extensive zone of previously unexplor...

  16. Electron-ion and ion-ion potentials for modeling warm dense matter: Applications to laser-heated or shock-compressed Al and Si.

    Science.gov (United States)

    Dharma-wardana, M W C

    2012-09-01

    The pair interactions Uij(r) determine the thermodynamics and linear transport properties of matter via the pair-distribution functions (PDFs), i.e., gij(r). Great simplicity is achieved if Uij(r) could be directly used to predict material properties via classical simulations, avoiding many-body wave functions. Warm dense matter (WDM) is encountered in quasiequilibria where the electron temperature Te differs from the ion temperature Ti, as in laser-heated or in shock-compressed matter. The electron PDFs gee(r) as perturbed by the ions are used to evaluate fully nonlocal exchange-correlation corrections to the free energy, using hydrogen as an example. Electron-ion potentials for ions with a bound core are discussed with Al and Si as examples, for WDM with Te≠Ti, and valid for times shorter than the electron-ion relaxation time. In some cases the potentials develop attractive regions and then become repulsive and "Yukawa-like" for higher Te. These results clarify the origin of initial phonon hardening and rapid release. Pair potentials for shock-heated WDM show that phonon hardening would not occur in most such systems. Defining meaningful quasiequilibrium static transport coefficients consistent with the dynamic values is addressed. There seems to be no meaningful "static conductivity" obtainable by extrapolating experimental or theoretical σ(ω,Ti,Te) to ω→0, unless Ti→Te as well. Illustrative calculations of quasistatic resistivities R(Ti,Te) of laser-heated as well as shock-heated aluminum and silicon are presented using our pseudopotentials, pair potentials, and classical integral equations. The quasistatic resistivities display clear differences in their temperature evolutions, but are not the strict ω→0 limits of the dynamic values.

  17. Evidence for out-of-equilibrium states in warm dense matter probed by X-ray Thomson scattering

    CERN Document Server

    Clerouin, J; Robert, G; Ticknor, C; Kress, J; Collins, L

    2014-01-01

    A recent and unexpected discrepancy between \\textit{ab initio} simulations and the interpretation of a laser shock experiment on aluminum, probed by X-ray Thomson scattering (XRTS), is addressed. The ion-ion structure factor deduced from the XRTS elastic peak (ion feature) is only compatible with a strongly coupled out-of-equilibrium state. Orbital free molecular dynamics simulations with ions colder than the electrons are employed to interpret the experiment. The relevance of decoupled temperatures for ions and electrons is discussed. The possibility that it mimics a transient, or metastable, out-of-equilibrium state after melting is also suggested.

  18. Uniform heating of materials into the warm dense matter regime with laser-driven quasi-monoenergetic ion beams

    CERN Document Server

    Bang, W; Bradley, P A; Vold, E L; Boettger, J C; Fernández, J C

    2015-01-01

    In a recent experiment on the Trident laser facility, a laser-driven beam of quasi-monoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 eV and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable on Trident, with a finite energy spread of (delta E)/E ~ 20%, are expected to heat the targets more uniformly than a beam of 140 MeV aluminum ions with zero energy spread. The robustness of the expected heating uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.

  19. Electron and ion dynamics study of iron in warm dense matter regime by time-resolved XAS measurements and from first-principles

    Science.gov (United States)

    Ogitsu, T.; Fernandez-Paãella, A.; Correa, A.; Engelhorn, K.; Barbrel, B.; Prendergast, D. G.; Pemmaraju, D.; Beckwith, M.; Kraus, D.; Hamel, S.; Cho, B. I.; Jin, L.; Wong, J.; Heinman, P.; Collins, G. W.; Falcone, R.; Ping, Y.

    2016-10-01

    We present a study of the electron-phonon coupling of warm dense iron upon femtosecond laser excitation by time-resolved x-ray absorption near edge spectroscopy (XANES). The dynamics of iron in electron-ion non-equilibrium conditions was studied using ab-initio density-functional-theory (DFT) simulations combined with the Two Temperature Model (TTM) where spatial inhomogeneity of electron (and ion) temperature(s) due to short ballistic electron transport length in iron was explicitly taken into consideration. Detailed comparison between our simulation results and experiments indicates that the ion temperature dependence on specific heat and on electron-phonon coupling also plays a relevant role in modeling the relaxation dynamics of electrons and ions. These results are the first experimental evidence of the suppression of the electron-phonon coupling factor of a transition metal at electron temperatures ranging 5000- 10000 K. This work was performed under DOE contract DE-AC52-07NA27344 with support from OFES Early Career program and LLNL LDRD program.

  20. Simulations of nonequilibrium warm dense gold produced by ultrafast heating

    Science.gov (United States)

    Holst, B.; Recoules, V.; Torrent, M.; Chen, Z.; Sametoglu, V.; Tsui, Y. Y.; Kirkwood, S. E.; Reid, M.; Mazevet, S.; Ng, A.

    2013-03-01

    The interaction of femtosecond laser pulses with metals produces nonequilibrium states consisting of hot electrons and cold ions. These can last for many picoseconds before relaxing to a thermodynamic equilibrium. Recent experiments using a chirped pulse probe technique provided AC conductivity data of gold at a sufficient time resolution to observe this relaxation process. We developed an ab-initio model that characterizes thermodynamic properties of warm dense matter states in nonequilibrium. Our theoretical scheme combines a standard two temperature model with temperature dependent material parameters and an energy transfer rate that are obtained by means of ab-initio simulations. This enables us to give a prediction for the temperature evolution during the relaxation process. Additionally, we derive the AC conductivity of the nonequilibrium states from our simulations using the Kubo-Greenwood formula. It is used to test our model against measurements. We observe agreement with experiment using an energy relaxation rate, that is smaller than predicted, giving us reason to revisit its determination. We can furthermore provide thermodynamical and structural data of nonequilibrium warm dense gold which are not accessible in experiment.

  1. Laser shocks on helium, hydrogen and diamond: an experimental study of the warm dense matter zone; Chocs laser sur l'helium, l'hydrogene et le diamant: une etude experimentale de la 'Warm Dense Matter'

    Energy Technology Data Exchange (ETDEWEB)

    Brygoo, St

    2006-11-15

    The purpose of this work was to develop a new approach of laser shocks on pre-compressed targets in order to collect data concerning the equation of state in the warm dense matter zone of the phase diagram. The accuracy of the measurement has been increased by the use of a new metrology based on quartz. Quartz is considered as a standard for the measurement of both the pressure and the density, a model of an isentropic relaxation based on a Grueneisen type approximation has been developed. By combining laser shocks with diamond anvil cells and by using this new metrology, we have investigated the following systems: diamond, helium, hydrogen, deuterium and hydrogen-helium mixtures. The results for helium agree very well with the predictions of the Saumon-Chabrier model. The results for deuterium are consistent with the latest results found in literature. As for the results concerning hydrogen, they have showed the limits of the quartz-based metrology. In fact, by being so little dense we are at the limit of the application range of the quartz relaxation. A mixture of helium-hydrogen (50 %) has been investigated, no sign of phase separation has been found.

  2. \\emph{Ab initio} Quantum Monte Carlo simulation of the warm dense electron gas

    CERN Document Server

    Dornheim, Tobias; Malone, Fionn; Schoof, Tim; Sjostrom, Travis; Foulkes, W M C; Bonitz, Michael

    2016-01-01

    Warm dense matter is one of the most active frontiers in plasma physics due to its relevance for dense astrophysical objects as well as for novel laboratory experiments in which matter is being strongly compressed e.g. by high-power lasers. Its description is theoretically very challenging as it contains correlated quantum electrons at finite temperature---a system that cannot be accurately modeled by standard analytical or ground state approaches. Recently several breakthroughs have been achieved in the field of fermionic quantum Monte Carlo simulations. First, it was shown that exact simulations of a finite model system ($30 \\dots 100$ electrons) is possible that avoid any simplifying approximations such as fixed nodes [Schoof {\\em et al.}, Phys. Rev. Lett. {\\bf 115}, 130402 (2015)]. Second, a novel way to accurately extrapolate these results to the thermodynamic limit was reported by Dornheim {\\em et al.} [Phys. Rev. Lett. {\\bf 117}, 156403 (2016)]. As a result, now thermodynamic results for the warm dense...

  3. Comprehensive Studies of Ultrafast Laser Excited Warm Dense Gold

    Science.gov (United States)

    Chen, Zhijiang; Mo, Mianzhen; Russell, Brandon; Tsui, Ying; Wang, Xijie; Ng, Andrew; Glenzer, Siegfried

    2016-10-01

    Isochoric excitation of solids by ultrafast laser pulses is an important approach to generate warm dense matter in laboratory. Electrical conductivity, structural dynamics and lattice stabilities are the most important properties in ultrafast laser excited warm dense matter. To investigate these properties, we have developed multiple advanced capabilities at SLAC recently, including the measurement of semi-DC electrical conductivity with ultrafast THz radiation, the study of solid and liquid structural dynamics by ultrafast electron diffraction (UED), and the investigation of lattice stability using frequency domain interferometry (FDI) on both front and rear surfaces. Due to the non-reversible nature in exciting solid to warm dense matter, all these diagnostics are implemented with single-shot approaches, reducing the uncertainties due to shot-to-shot fluctuations. In this talk, we will introduce these novel capabilities and present some highlighted studies in warm dense gold, which was uniformly excited by ultrafast laser pulses at 400nm. We appreciate the supports from DOE FES under FWP #100182.

  4. Novel diagnostics for warm dense matter: application to shock compressed target; Nouveaux diagnostics pour l'etude de la matiere dense et chaude: application aux cibles comprimees par choc laser

    Energy Technology Data Exchange (ETDEWEB)

    Ravasio, A

    2007-03-15

    In this work, we present 3 novel diagnostics for warm dense plasma (WDM) investigations: hard X-ray radiography, proton radiography and X-ray Thomson scattering. Each of these techniques is applied in shock compression experiments. The main objective consists in accessing a new parameter, in addition to shock and particle velocity, for EOS (Equation of State) measurements. In the first chapter we give a deep description of WDM states as strongly coupled and Fermi degenerate states. Then, we introduce how we have generated a WDM state in our experiment: the shock wave. We, in particular, illustrate its formation in the classical laser-matter interaction regime. In the second chapter the principles of standard probing techniques are presented. We see that energetic probe sources are necessary to investigate high Z dense plasmas. The third chapter is dedicated to X-ray radiography results. We report on a first direct density measurement of a shock compressed high Z target using K{alpha} hard X-ray radiation. These results are of great interests as they allow an in-situ characterization of high Z material, impossible with standard techniques. We show that probing a well known material as Al will allow the comparison between our data and the results from already validated simulations. In the fourth chapter, we present the results obtained from proton radiography on low density carbon foam. The data analysis will require the development of a specific Monte-Carlo code to simulate the proton propagation through the shocked target. The comparison of the simulations with the experimental data show a low dependency on density. The fifth chapter is devoted to X-ray Thomson scattering results. For the first time, we have performed collective x-ray Thomson scattering measurement from a shock compressed target, accessing to electron density and temperature. The obtained results are compared with simulated x-ray scattered spectra. The novel technique is then used in the

  5. Interband and intraband electron kinetics in non-thermal warm dense gold

    Science.gov (United States)

    Brennan Brown, Shaughnessy; Chen, Zhijiang; Curry, Chandra; Hering, Philippe; Hoffmann, Matthias C.; Ng, Andrew; Reid, Matthew; Tsui, Ying Y.; Glenzer, Siegfried H.

    2015-11-01

    Single-state warm dense matter may be produced via isochoric heating of thin metal foils using ultrafast high-power lasers. Previous experiments have confirmed that electron temperatures exceed ion temperatures during the initial picoseconds following excitation; however, electron kinetics in non-thermal states preceding establishment of a well-defined electron thermal distribution remain little understood. X-ray and optical probing techniques provide necessary resolution to investigate these electronic properties. Here, we will present a study of electron kinetics in warm dense gold produced by irradiating free-standing 30 nm Au foils with a 400 nm FWHM, 45 fs Ti:Sapphire laser system at SLAC National Accelerator Laboratory. The temporal evolutions of AC conductivity for 400 nm and 800 nm laser pulses are simultaneously determined with sub-100 fs resolution, providing insight into the 5 d-6 s/ p interband and 6 s / p intraband transitions respectively. Our results suggest that Auger decay and three-body recombination play important roles in electron thermalization of warm dense gold.

  6. Wave packet molecular dynamics simulations of warm dense hydrogen

    CERN Document Server

    Knaup, M; Toepffer, C; Zwicknagel, G

    2003-01-01

    Recent shock-wave experiments with deuterium in a regime where a plasma phase-transition has been predicted and their theoretical interpretation are the matter of a controversial discussion. In this paper, we apply 'wave packet molecular dynamics' (WPMD) simulations to investigate warm dense hydrogen. The WPMD method was originally used by Heller for a description of the scattering of composite particles such as simple atoms and molecules; later it was applied to Coulomb systems by Klakow et al. In the present version of our model the protons are treated as classical point-particles, whereas the electrons are represented by a completely anti-symmetrized Slater sum of periodic Gaussian wave packets. We present recent results for the equation of state of hydrogen at constant temperature T = 300 K and of deuterium at constant Hugoniot E - E sub 0 + 1/2(1/n - 1/n sub 0)(p + p sub 0) = 0, and compare them with the experiments and several theoretical approaches.

  7. Thermophysical properties of warm dense hydrogen

    CERN Document Server

    Holst, Bastian; Desjarlais, Michael P

    2007-01-01

    We study the thermophysical properties of warm dense hydrogen using quantum molecular dynamics simulations. New results are presented for the pair distribution functions, the equation of state, the Hugoniot curve, and the reflectivity. We compare with available experimental data and predictions of the chemical picture. Especially, we discuss the nonmetal-to-metal transition which occurs at about 40 GPa in the dense fluid.

  8. Generation of warm dense matter and strongly coupled plasmas using the High Radiation on Materials facility at the CERN Super Proton Synchrotron

    CERN Document Server

    Tahir, N A; Brugger, M; Assmann, R; Shutov, A; Lomonosov, I V; Gryaznov, V; Piriz, A R; Udrea, S; Hoffmann, D H H; Fortov, V E; Deutsch, C

    2009-01-01

    A dedicated facility named High Radiation on Materials (HiRadMat) is being constructed at CERN to study the interaction of the 450 GeV protons generated by the Super Proton Synchrotron (SPS) with fixed solid targets of different materials. The main purpose of these future experiments is to study the generation and propagation of thermal shock waves in the target in order to assess the damage caused to the equipment, including collimators and absorbers, in case of an accident involving an uncontrolled release of the entire beam at a given point. Detailed numerical simulations of the beam-target interaction of several cases of interest have been carried out. In this paper we present simulations of the thermodynamic and the hydrodynamic response of a solid tungsten cylindrical target that is facially irradiated with the SPS beam with nominal parameters. These calculations have been carried out in two steps. First, the energy loss of the protons is calculated in the solid target using the FLUKA code (Fasso et al....

  9. Plasmon resonance in warm dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Thiele, R; Bornath, T; Fortmann, C; Holl, A; Redmer, R; Reinholz, H; Ropke, G; Wierling, A; Glenzer, S H; Gregori, G

    2008-02-21

    Collective Thomson scattering with extreme ultraviolet light or x-rays is shown to allow for a robust measurement of the free electron density in dense plasmas. Collective excitations like plasmons appear as maxima in the scattering signal. Their frequency position can directly be related to the free electron density. The range of applicability of the standard Gross-Bohm dispersion relation and of an improved dispersion relation in comparison to calculations based on the dielectric function in random phase approximation is investigated. More important, this well-established treatment of Thomson scattering on free electrons is generalized in the Born-Mermin approximation by including collisions. We show that, in the transition region from collective to non-collective scattering, the consideration of collisions is important.

  10. Warm dense mater: another application for pulsed power hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Reinovsky, Robert Emil [Los Alamos National Laboratory

    2009-01-01

    Pulsed Power Hydrodynamics (PPH) is an application of low-impedance pulsed power, and high magnetic field technology to the study of advanced hydrodynamic problems, instabilities, turbulence, and material properties. PPH can potentially be applied to the study of the properties of warm dense matter (WDM) as well. Exploration of the properties of warm dense matter such as equation of state, viscosity, conductivity is an emerging area of study focused on the behavior of matter at density near solid density (from 10% of solid density to slightly above solid density) and modest temperatures ({approx}1-10 eV). Conditions characteristic of WDM are difficult to obtain, and even more difficult to diagnose. One approach to producing WDM uses laser or particle beam heating of very small quantities of matter on timescales short compared to the subsequent hydrodynamic expansion timescales (isochoric heating) and a vigorous community of researchers are applying these techniques. Pulsed power hydrodynamic techniques, such as large convergence liner compression of a large volume, modest density, low temperature plasma to densities approaching solid density or through multiple shock compression and heating of normal density material between a massive, high density, energetic liner and a high density central 'anvil' are possible ways to reach relevant conditions. Another avenue to WDM conditions is through the explosion and subsequent expansion of a conductor (wire) against a high pressure (density) gas background (isobaric expansion) techniques. However, both techniques demand substantial energy, proper power conditioning and delivery, and an understanding of the hydrodynamic and instability processes that limit each technique. In this paper we will examine the challenges to pulsed power technology and to pulsed power systems presented by the opportunity to explore this interesting region of parameter space.

  11. Rapid heating of matter using high power lasers

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Woosuk [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-08

    This slide presentation describes motivation (uniform and rapid heating of a target, opportunity to study warm dense matter, study of nuclear fusion reactions), rapid heating of matter with intense laser-driven ion beams, visualization of the expanding warm dense gold and diamond, and nuclear fusion experiments using high power lasers (direct heating of deuterium spheres (radius ~ 10nm) with an intense laser pulse.

  12. Thermal conductivity measurements of warm dense iron at the LCLS

    Science.gov (United States)

    McKelvey, A.; Jiang, S.; Collins, G.; Shepherd, R.; Hau-Riege, S. P.; Hill, M. P.; Brown, C. R. D.; Floyd, E.; Fyrth, J. D.; Skidmore, J. W.; Hua, R.; Beg, F. N.; Kim, M.; Cho, B.; Lee, J.; King, J.; Freeman, R. R.; Lee, H. J.; Galtier, E.; Audebert, P.; Levy, A.; Ping, Y.

    2016-10-01

    Accurate knowledge of conductivity characteristics in the strongly coupled plasma regime is extremely important for ICF processes such as the onset of hydrodynamic instabilities, thermonuclear burn propagation waves, shell mixing, and efficient x-ray conversion of indirect drive schemes. Recently, an experiment was performed at the LCLS at SLAC to measure the thermal conductivity of warm dense iron. The experiment used 6.8 keV x-rays to differentially heat thin bi-layer Au/Fe targets and establish a prompt temperature gradient at the layer interface. We used a SOP and a FDI to measure the rear layer's time-resolved temperature, expansion velocity, and reflectivity. Data from the time-resolved diagnostics for 100 nm Au and 50 to 100 nm Fe targets will be presented along with analysis and comparison with various models in the strongly coupled plasma regime. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

  13. Equation of state and transport properties of warm dense helium via quantum molecular dynamics simulations

    Science.gov (United States)

    Li, Zhi-Guo; Cheng, Yan; Chen, Qi-Feng; Chen, Xiang-Rong

    2016-05-01

    The equation of state, self-diffusion, and viscosity coefficients of helium have been investigated by quantum molecular dynamics (QMD) simulations in the warm dense matter regime. Our simulations are validated through the comparison with the reliable experimental data. The calculated principal and reshock Hugoniots of liquid helium are in good agreement with the gas-gun data. On this basis, we revisit the issue for helium, i.e., the possibility of the instabilities predicted by chemical models at around 2000 GPa and 10 g/cm3 along the pressure isotherms of 6309, 15 849, and 31 623 K. Our calculations show no indications of instability in this pressure-temperature region, which reconfirm the predictions of previous QMD simulations. The self-diffusion and viscosity coefficients of warm dense helium have been systematically investigated by the QMD simulations. We carefully test the finite-size effects and convergences of statistics, and obtain numerically converged self-diffusion and viscosity coefficients by using the Kubo-Green formulas. The present results have been used to evaluate the existing one component plasma models. Finally, the validation of the Stokes-Einstein relationship for helium in the warm dense regime is discussed.

  14. Soft X-ray spectrometer design for warm dense plasma measurements on DARHT Axis-I

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, Nicholas Bryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Perry, John Oliver [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Coleman, Joshua Eugene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-11

    A preliminary design study is being performed on a soft X-ray spectrometer to measure K-shell spectra emitted by a warm dense plasma generated on Axis-I of the Dual-Axis Radiographic Hydrodynamic Testing (DARHT) facility at Los Alamos National Laboratory. The 100-ns-long intense, relativistic electron pulse with a beam current of 1.7 kA and energy of 19.8 MeV deposits energy into a thin metal foil heating it to a warm dense plasma. The collisional ionization of the target by the electron beam produces an anisotropic angular distribution of K-shell radiation and a continuum of both scattered electrons and Bremsstrahlung up to the beam energy of 19.8 MeV. The principal goal of this project is to characterize these angular distributions to determine the optimal location to deploy the soft X-ray spectrometer. In addition, a proof-of-principle design will be presented. The ultimate goal of the spectrometer is to obtain measurements of the plasma temperature and density to benchmark equation-of-state models of the warm dense matter regime.

  15. Time-resolved X-ray Absorption Spectroscopy for Electron Transport Study in Warm Dense Gold

    Science.gov (United States)

    Lee, Jong-Won; Bae, Leejin; Engelhorn, Kyle; Heimann, Philip; Ping, Yuan; Barbrel, Ben; Fernandez, Amalia; Beckwith, Martha Anne; Cho, Byoung-Ick; GIST Team; IBS Team; LBNL Collaboration; SLAC Collaboration; LLNL Collaboration

    2015-11-01

    The warm dense Matter represents states of which the temperature is comparable to Fermi energy and ions are strongly coupled. One of the experimental techniques to create such state in the laboratory condition is the isochoric heating of thin metal foil with femtosecond laser pulses. This concept largely relies on the ballistic transport of electrons near the Fermi-level, which were mainly studied for the metals in ambient conditions. However, they were barely investigated in warm dense conditions. We present a time-resolved x-ray absorption spectroscopy measured for the Au/Cu dual layered sample. The front Au layer was isochorically heated with a femtosecond laser pulse, and the x-ray absorption changes around L-edge of Cu, which was attached on the backside of Au, was measured with a picosecond resolution. Time delays between the heating of the `front surface' of Au layer and the alternation of x-ray spectrum of Cu attached on the `rear surface' of Au indicate the energetic electron transport mechanism through Au in the warm dense conditions. IBS (IBS-R012-D1) and the NRF (No. 2013R1A1A1007084) of Korea.

  16. Soft X-Ray Thomson Scattering in Warm Dense Hydrogen at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Faustlin, R R; Toleikis, S; Bornath, T; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gode, S; Gregori, G; Irsig, R; Laarmann, T; Lee, H J; Li, B; Meiwes-Broer, K; Mithen, J; Przystawik, A; Redlin, H; Redmer, R; Reinholz, H; Ropke, G; Tavella, F; Thiele, R; Tiggesbaumker, J; Uschmann, I; Zastrau, U; Tschentscher, T

    2009-07-15

    We present collective Thomson scattering with soft x-ray free electron laser radiation as a method to track the evolution of warm dense matter plasmas with {approx}200 fs time resolution. In a pump-probe scheme an 800 nm laser heats a 20 {micro}m hydrogen droplet to the plasma state. After a variable time delay in the order of ps the plasma is probed by an x-ray ultra violet (XUV) pulse which scatters from the target and is recorded spectrally. Alternatively, in a self-Thomson scattering experiment, a single XUV pulse heats the target while a portion of its photons are being scattered probing the target. From such inelastic x-ray scattering spectra free electron temperature and density can be inferred giving insight on relaxation time scales in plasmas as well as the equation of state. We prove the feasibility of this method in the XUV range utilizing the free electron laser facility in Hamburg, FLASH. We recorded Thomson scattering spectra for hydrogen plasma, both in the self-scattering and in the pump-probe mode using optical laser heating.

  17. Laboratory measurements of the resistivity of warm dense plasmas

    Science.gov (United States)

    Booth, Nicola; Robinson, Alex; Hakel, Peter; Gregori, Ginaluca; Rajeev, Pattathil; Woolsey, Nigel

    2015-11-01

    In this talk we will present a method for studying material resistivity in warm dense plasmas in the laboratory in which we interrogate the microphysics of the low energy electron distributions associated with an anisotropic return current. Through experimental measurements of the polarization of the Ly- α doublet emission (2s1 / 2-2p1 / 2,3/2 transitions) of sulphur, we determine the resistivity of a sulphur-doped plastic target heated to warm dense conditions by an ultra-intense laser at relativistic intensities, I ~ 5 ×1020 Wcm-2. We describe a method of exploiting classical x-ray scattering to separately measure both the π- and σ- polarizations of Ly-α1 spectral emission in a single shot. These measurements make it possible to explore fundamental material properties such as resistivity in warm and hot dense plasmas through matching plasma physics modelling to atomic physics calculations of the experimentally measured large, positive, polarisation.

  18. Measurement of Electron-Ion Relaxation in Warm Dense Copper

    Science.gov (United States)

    Cho, B. I.; Ogitsu, T.; Engelhorn, K.; Correa, A. A.; Ping, Y.; Lee, J. W.; Bae, L. J.; Prendergast, D.; Falcone, R. W.; Heimann, P. A.

    2016-01-01

    Experimental investigation of electron-ion coupling and electron heat capacity of copper in warm and dense states are presented. From time-resolved x-ray absorption spectroscopy, the temporal evolution of electron temperature is obtained for non-equilibrium warm dense copper heated by an intense femtosecond laser pulse. Electron heat capacity and electron-ion coupling are inferred from the initial electron temperature and its decrease over 10 ps. Data are compared with various theoretical models.

  19. Stopping of deuterium in warm dense deuterium from Ehrenfest time-dependent density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Magyar, R.J.; Shulenburger, L.; Baczewski, A.D. [Sandia National Laboratories - Multi-scale Physics 1444 MS 1322, Albuquerque, NM (United States)

    2016-06-15

    In these proceedings, we show that time-dependent density functional theory is capable of stopping calculations at the extreme conditions of temperature and pressure seen in warm dense matter. The accuracy of the stopping curves tends to be up to about 20% lower than empirical models that are in use. However, TDDFT calculations are free from fitting parameters and assumptions about the model form of the dielectric function. This work allows the simulation of ion stopping in many materials that are difficult to study experimentally. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Time evolution of electron structure in femtosecond heated warm dense molybdenum.

    Science.gov (United States)

    Recoules, V.; Dorchies, F.; Bouchet, J.; Fourment, C.; Leguay, P. M.; Cho, B. I.; Engelhorn, K.; Nakatsutsumi, M.; Ozkan, C.; Tshentscher, T.; Harmand, M.; Toleikis, S.; Stormer, M.; Galtier, E.; Lee, H. J.; Nagler, B.; Heimann, P. A.; Gaudin, J.

    2015-11-01

    The time evolution of the electron structure is investigated in a molybdenum foil heated up to the warm dense matter regime by a femtosecond laser pulse, through time-resolved XANES spectroscopy. Spectra are measured with independent control of temperature and density. They are successfully compared with ab initio quantum molecular dynamic calculations and an analytical model. We demonstrate that the observed white line in the L3-edge reveals the time evolution of the electron density of state from the solid to the hot (a few eV) and expanding liquid.

  1. Observations of non-collective x-ray scattering in warm dense carbon plasma

    Science.gov (United States)

    Lihua, Bao; Jiyan, Zhang; Xiaoding, Zhang; Yang, Zhao; Yongkun, Ding

    2012-12-01

    An experiment for observing the spectrally resolved non-collective x-ray scattering in warm dense carbon plasma is presented in this paper. The experiment used Ta M-band x-rays to heat a foamed carbon cylinder sample isochorically and measured the scattering spectrum with a HOPG crystal spectrometer. The spectrum was compared with the calculation results using a Born-Mermin-approximation model. The best fitting was found at an electron temperature of Te=34 eV and an electron density of ne=1.6×1023cm-3.

  2. Equation of state and opacities for warm dense matter

    Directory of Open Access Journals (Sweden)

    Cotelo Manuel

    2013-11-01

    Full Text Available This work presents recent developments in the calculation of opacity and equation of state tables suitable for including in the radiation hydrodynamic code ARWEN [1] to study processes like ICF or X-ray secondary sources. For these calculations we use the code bigbart to compute opacities in LTE conditions, with self-consistent data generated with the Flexible Atomic Code (FAC [2]. Non-LTE effects are approximately taken into account by means of the new RADIOM model developed in [3], which makes use of existing LTE data tables. We use the screened-hydrogenic model [4] to derive the Equation of State (EOS using the population and energy of each level.

  3. The ab initio equation of state of hydrogen in the warm dense matter and its application to the implosion of targets for the inertial confinement fusion; Equation d'etat ab initio de l'hydrogene dans la matiere dense et tiede et application a l'implosion de cibles pour la fusion par confinement inertiel

    Energy Technology Data Exchange (ETDEWEB)

    Caillabet, L.

    2011-03-25

    In the field of the inertial confinement fusion (ICF), the equation of state (EoS) of the hydrogen and its isotopes is one of the most important properties to know. The EoS based on chemical models have difficulty in giving an unambiguous description of the hydrogen in the strong coupled and partial degenerate regime, called Warm Dense Matter (WDM). Indeed, these models use potential with adjustable parameters to describe the many body interactions which are important in the WDM. On the other hand, the ab initio methods resolve almost exactly the quantum many body problem and are thus particularly relevant in this domain. In the first part of this thesis, we describe how we built a table of a multi-phase EoS of the hydrogen, using ab initio methods in the field of the WDM. We show in particular that this EoS is in very good agreement with most of the available experimental data (principal Hugoniot, sound velocity in the molecular fluid, melting curve at low pressure, measurements of multiple shocks). In the second part, we present a direct application of our EoS by showing its influence on the criteria of ignition and combustion of two target designs for ICF: a self-ignited target which will be used on the Laser MegaJoule (LMJ), and a shock-ignited target. We show in particular that the optimization of the laser pulse allowing maximizing the thermonuclear energy is strongly dependent on the precision of the EoS in the strong coupled and degenerate domain. (author) [French] Dans le domaine de la fusion par confinement inertiel (FCI), l'equation d'etat (EoS) de l'hydrogene et de ses isotopes est tres certainement une des proprietes les plus importantes a connaitre. Les EoS basees sur des modeles chimiques peinent a donner une description univoque de l'hydrogene dans le domaine de couplage et de degenerescence partiels, appele matiere dense et tiede, ou Warm Dense Matter (WDM). En effets, ces modeles utilisent des potentiels ad hoc pour decrire les

  4. First-Principles Calculation of Principal Hugoniot and K-Shell X-ray Absorption Spectra for Warm Dense KCl

    CERN Document Server

    Zhao, Shijun; Kang, Wei; Li, Zi; Zhang, Ping; He, Xian-Tu

    2015-01-01

    Principal Hugoniot and K-shell X-ray absorption spectra of warm dense KCl are calculated using the first-principles molecular dynamics method. Evolution of electronic structures as well as the influence of the approximate description of ionization on pressure (caused by the underestimation of the energy gap between conduction bands and valence bands) in the first-principles method are illustrated by the calculation. Pressure ionization and thermal smearing are shown as the major factors to prevent the deviation of pressure from global accumulation along the Hugoniot. In addition, cancellation between electronic kinetic pressure and virial pressure further reduces the deviation. The calculation of X-ray absorption spectra shows that the band gap of KCl persists after the pressure ionization of the $3p$ electrons of Cl and K taking place at lower energy, which provides a detailed understanding to the evolution of electronic structures of warm dense matter.

  5. Impact of First-Principles Property Calculations of Warm-Dense Deuterium/Tritium on Inertial Confinement Fusion Target Designs

    Science.gov (United States)

    Hu, S. X.

    2014-10-01

    Accurate knowledge of the properties of warm dense deuterium/tritium (DT) is essential to reliably design inertial confinement fusion (ICF) implosions. In the warm-dense-matter regime, routinely accessed by low-adiabat ICF implosions, strong-coupling and degeneracy effects play an important role in determining plasma properties. Using first-principles methods of both path-integral Monte Carlo and quantum molecular-dynamics (QMD), we have performed systematic investigation of the equation of state, thermal conductivity, and opacity for DT over a wide range of densities and temperatures. These first-principles properties have been incorporated into our hydrocodes. When compared to hydro simulations using standard plasma models, significant differences in 1-D target performance have been identified for simulations of DT implosions. For low-adiabat (α Administration under Award Number DE-NA0001944.

  6. Equilibration dynamics and conductivity of warm dense hydrogen

    Science.gov (United States)

    Zastrau, U.; Sperling, P.; Becker, A.; Bornath, T.; Bredow, R.; Döppner, T.; Dziarzhytski, S.; Fennel, T.; Fletcher, L. B.; Förster, E.; Fortmann, C.; Glenzer, S. H.; Göde, S.; Gregori, G.; Harmand, M.; Hilbert, V.; Holst, B.; Laarmann, T.; Lee, H. J.; Ma, T.; Mithen, J. P.; Mitzner, R.; Murphy, C. D.; Nakatsutsumi, M.; Neumayer, P.; Przystawik, A.; Roling, S.; Schulz, M.; Siemer, B.; Skruszewicz, S.; Tiggesbäumker, J.; Toleikis, S.; Tschentscher, T.; White, T.; Wöstmann, M.; Zacharias, H.; Redmer, R.

    2014-07-01

    We investigate subpicosecond dynamics of warm dense hydrogen at the XUV free-electron laser facility (FLASH) at DESY (Hamburg). Ultrafast impulsive electron heating is initiated by a ≤300-fs short x-ray burst of 92-eV photon energy. A second pulse probes the sample via x-ray scattering at jitter-free variable time delay. We show that the initial molecular structure dissociates within (0.9±0.2) ps, allowing us to infer the energy transfer rate between electrons and ions. We evaluate Saha and Thomas-Fermi ionization models in radiation hydrodynamics simulations, predicting plasma parameters that are subsequently used to calculate the static structure factor. A conductivity model for partially ionized plasma is validated by two-temperature density-functional theory coupled to molecular dynamic simulations and agrees with the experimental data. Our results provide important insights and the needed experimental data on transport properties of dense plasmas.

  7. Bremsstrahlung and Line Spectroscopy of Warm Dense Aluminum Plasma Generated by EUV Free Electron Laser

    Energy Technology Data Exchange (ETDEWEB)

    Zastrau, U; Fortmann, C; Faustlin, R; Bornath, T; Cao, L F; Doppner, T; Dusterer, S; Forster, E; Glenzer, S H; Gregori, G; Holl, A; Laarmann, T; Lee, H; Meiwes-Broer, K; Przystawik, A; Radcliffe, P; Redmer, R; Reinholz, H; Ropke, G; Tiggesbaumker, J; Thiele, R; Truong, N X; Uschmann, I; Toleikis, S; Tschentscher, T; Wierling, A

    2008-03-07

    We report on the novel creation of a solid density aluminum plasma using free electron laser radiation at 13.5 nm wavelength. Ultrashort pulses of 30 fs duration and 47 {micro}J pulse energy were focused on a spot of 25 {micro}m diameter, yielding an intensity of 3 x 10{sup 14} W/cm{sup 2} on the bulk Al-target. The radiation emitted from the plasma was measured using a high resolution, high throughput EUV spectrometer. The analysis of both bremsstrahlung and line spectra results in an estimated electron temperature of (30 {+-} 10) eV, which is in very good agreement with radiation hydrodynamics simulations of the laser-target-interaction. This demonstrates the feasibility of exciting plasmas at warm dense matter conditions using EUV free electron lasers and their accurate characterization by EUV spectroscopy.

  8. A proposed experimental platform for measuring the properties of warm dense mixtures: Testing the applicability of the linear mixing model

    Science.gov (United States)

    Hawreliak, James

    2017-06-01

    This paper presents a proposed experimental technique for investigating the impact of chemical interactions in warm dense liquid mixtures. It uses experimental equation of state (EOS) measurements of warm dense liquid mixtures with different compositions to determine the deviation from the linear mixing model. Statistical mechanics is used to derive the EOS of a mixture with a constant pressure linear mixing term (Amagat's rule) and an interspecies interaction term. A ratio between the particle density of two different compositions of mixtures, K(P, T)i: ii, is defined. By comparing this ratio for a range of mixtures, the impact of interspecies interactions can be studied. Hydrodynamic simulations of mixtures with different carbon/hydrogen ratios are used to demonstrate the application of this proposed technique to multiple shock and ramp compression experiments. The limit of the pressure correction that can be measured due to interspecies interactions using this methodology is determined by the uncertainty in the density measurement.

  9. Shock-adiabatic to quasi-isentropic compression of warm dense helium up to 150 GPa

    Science.gov (United States)

    Zheng, J.; Chen, Q. F.; Gu, Y. J.; Li, J. T.; Li, Z. G.; Li, C. J.; Chen, Z. Y.

    2017-06-01

    Multiple reverberation compression can achieve higher pressure, higher temperature, but lower entropy. It is available to provide an important validation for the elaborate and wider planetary models and simulate the inertial confinement fusion capsule implosion process. In the work, we have developed the thermodynamic and optical properties of helium from shock-adiabatic to quasi-isentropic compression by means of a multiple reverberation technique. By this technique, the initial dense gaseous helium was compressed to high pressure and high temperature and entered the warm dense matter (WDM) region. The experimental equation of state (EOS) of WDM helium in the pressure-density-temperature (P-ρ -T) range of 1 -150 GPa , 0.1 -1.1 g c m-3 , and 4600-24 000 K were measured. The optical radiations emanating from the WDM helium were recorded, and the particle velocity profiles detecting from the sample/window interface were obtained successfully up to 10 times compression. The optical radiation results imply that dense He has become rather opaque after the 2nd compression with a density of about 0.3 g c m-3 and a temperature of about 1 eV. The opaque states of helium under multiple compression were analyzed by the particle velocity measurements. The multiple compression technique could efficiently enhanced the density and the compressibility, and our multiple compression ratios (ηi=ρi/ρ0,i =1 -10 ) of helium are greatly improved from 3.5 to 43 based on initial precompressed density (ρ0) . For the relative compression ratio (ηi'=ρi/ρi -1) , it increases with pressure in the lower density regime and reversely decreases in the higher density regime, and a turning point occurs at the 3rd and 4th compression states under the different loading conditions. This nonmonotonic evolution of the compression is controlled by two factors, where the excitation of internal degrees of freedom results in the increasing compressibility and the repulsive interactions between the

  10. Quantum molecular dynamics simulations of equation of state of warm dense ethane

    Science.gov (United States)

    Li, Chuan-Ying; Wang, Cong; Li, Yong-Sheng; Li, Da-Fang; Li, Zi; Zhang, Ping

    2016-09-01

    The equation of state of warm dense ethane is obtained using quantum molecular dynamics simulations based on finite-temperature density functional theory for densities from 0.1 g / cm 3 to 3.1 g / cm 3 and temperatures from 0.1 eV to 5.17 eV. The calculated pressure and internal energy are fitted with cubic polynomials in terms of density and temperature. Specific density-temperature-pressure tracks such as the principal and double shock Hugoniot curves along with release isentropes are predicted which are fundamental for the analysis and interpretation of high-pressure experiments. The principal and double shock Hugoniot curves are in agreement with the experimental data from the Sandia Z-Machine [Magyar et al., Phys. Rev. B 91, 134109 (2015)].

  11. First-principles calculations of X-ray absorption spectra for warm dense methane

    Science.gov (United States)

    Li, Zi; Wang, Cong; Li, Dafang; Kang, Wei; Zhang, Ping

    2017-09-01

    X-ray absorption spectrum is a powerful tool for atomic structure detection on materials under extreme conditions. Here, we perform first-principles molecular dynamics and X-ray absorption spectrum calculations for warm dense methane under thermodynamical conditions along a Hugoniot curve. From the molecular dynamics trajectories, the detailed atomic structures are examined for each condition. The carbon K-shell X-ray absorption spectrum is calculated, and its change with temperature and pressure is discussed. The methane systems under extreme conditions may contain radicals CHx (x = 1,2,3), molecules CH4, and carbon chains CmHn (m,n >1). These various products show quite different contributions to the total X-ray spectrum due to the different atomic and electronic structures. The change of the total X-ray spectrum along the Hugoniot curve is then attributed to the change of the products induced by the temperature and pressure. Some clear signatures on the X-ray absorption spectrum under different thermodynamical conditions are proposed, which provide useful information for future X-ray experiments.

  12. Probing warm dense silica with betatron radiation - Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Kotick, Jordan [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-24

    Laser wakefield acceleration (LWFA) has been shown to produce short X-ray pulses from oscillations of electrons within the plasma wake. These betatron X-rays pulses have a broad, synchrotron-like energy spectrum and a duration on the order of the driving laser pulse, thereby enabling probing of ultrafast interactions. Using the 1 J, 40fs short-pulse laser at the Matter in Extreme Conditions experimental station at LCLS, we have implemented LWFA to generate and subsequently characterized betatron X-rays. A scintillator and lanex screen were used to measure the charge fluence and energy spectrum of the produced electron beam.

  13. Enhanced relativistic-electron-beam energy loss in warm dense aluminum.

    Science.gov (United States)

    Vaisseau, X; Debayle, A; Honrubia, J J; Hulin, S; Morace, A; Nicolaï, Ph; Sawada, H; Vauzour, B; Batani, D; Beg, F N; Davies, J R; Fedosejevs, R; Gray, R J; Kemp, G E; Kerr, S; Li, K; Link, A; McKenna, P; McLean, H S; Mo, M; Patel, P K; Park, J; Peebles, J; Rhee, Y J; Sorokovikova, A; Tikhonchuk, V T; Volpe, L; Wei, M; Santos, J J

    2015-03-01

    Energy loss in the transport of a beam of relativistic electrons in warm dense aluminum is measured in the regime of ultrahigh electron beam current density over 2×10^{11}  A/cm^{2} (time averaged). The samples are heated by shock compression. Comparing to undriven cold solid targets, the roles of the different initial resistivity and of the transient resistivity (upon target heating during electron transport) are directly observable in the experimental data, and are reproduced by a comprehensive set of simulations describing the hydrodynamics of the shock compression and electron beam generation and transport. We measured a 19% increase in electron resistive energy loss in warm dense compared to cold solid samples of identical areal mass.

  14. Ab Initio Quantum Monte Carlo Simulation of the Warm Dense Electron Gas in the Thermodynamic Limit

    Science.gov (United States)

    Dornheim, Tobias; Groth, Simon; Sjostrom, Travis; Malone, Fionn D.; Foulkes, W. M. C.; Bonitz, Michael

    2016-10-01

    We perform ab initio quantum Monte Carlo (QMC) simulations of the warm dense uniform electron gas in the thermodynamic limit. By combining QMC data with the linear response theory, we are able to remove finite-size errors from the potential energy over the substantial parts of the warm dense regime, overcoming the deficiencies of the existing finite-size corrections by Brown et al. [Phys. Rev. Lett. 110, 146405 (2013)]. Extensive new QMC results for up to N =1000 electrons enable us to compute the potential energy V and the exchange-correlation free energy Fxc of the macroscopic electron gas with an unprecedented accuracy of |Δ V |/|V |,|Δ Fxc|/|F |xc˜10-3 . A comparison of our new data to the recent parametrization of Fxc by Karasiev et al. [Phys. Rev. Lett. 112, 076403 (2014)] reveals significant deviations to the latter.

  15. Resolving electrical conductivities from collisionally damped plasmons in isochorically heated warm dense aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Sperling, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fletcher, L. B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Chung, H. -K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gamboa, E. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lee, H. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Omarbakiyeva, Y. [International IT Univ., Almaty (Kazakhstan); Univ. Rostock (Germany); Reinholz, H. [Univ. Rostock (Germany); ; Univ. of Western Australia, Crawley, WA (Australia); Ropke, G. [Univ. Rostock (Germany); Rosmej, S. [Univ. Rostock (Germany); Zastrau, U. [European XFEL, Hamburg (Germany); Glenzer, S. H. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-03-29

    We measure the highly-resolved inelastic x-ray scattering spectrum of isochorically ultrafast heated aluminum. In the x-ray forward scattering spectra the electron temperature could be measured from the down- and upshifted plasmon, where the electron density of ne = 1:8 1023 cm3 is known a priori. We have studied the plasmon damping by applying electron-particle collision models beyond the Born approximation determining the electrical conductivity of warm dense aluminum.

  16. Experimental measurements of the collisional absorption of XUV radiation in warm dense aluminium

    Science.gov (United States)

    Kettle, B.; Dzelzainis, T.; White, S.; Li, L.; Dromey, B.; Zepf, M.; Lewis, C. L. S.; Williams, G.; Künzel, S.; Fajardo, M.; Dacasa, H.; Zeitoun, Ph.; Rigby, A.; Gregori, G.; Spindloe, C.; Heathcote, R.; Riley, D.

    2016-08-01

    The collisional (or free-free) absorption of soft x rays in warm dense aluminium remains an unsolved problem. Competing descriptions of the process exist, two of which we compare to our experimental data here. One of these is based on a weak scattering model, another uses a corrected classical approach. These two models show distinctly different behaviors with temperature. Here we describe experimental evidence for the absorption of 26-eV photons in solid density warm aluminium (Te≈1 eV). Radiative x-ray heating from palladium-coated CH foils was used to create the warm dense aluminium samples and a laser-driven high-harmonic beam from an argon gas jet provided the probe. The results indicate little or no change in absorption upon heating. This behavior is in agreement with the prediction of the corrected classical approach, although there is not agreement in absolute absorption value. Verifying the correct absorption mechanism is decisive in providing a better understanding of the complex behavior of the warm dense state.

  17. Equations of state and transport properties of warm dense beryllium: a quantum molecular dynamics study.

    Science.gov (United States)

    Wang, Cong; Long, Yao; Tian, Ming-Feng; He, Xian-Tu; Zhang, Ping

    2013-04-01

    We have calculated the equations of state, the viscosity and self-diffusion coefficients, and electronic transport coefficients of beryllium in the warm dense regime for densities from 4.0 to 6.0 g/cm(3) and temperatures from 1.0 to 10.0 eV by using quantum molecular dynamics simulations. The principal Hugoniot curve is in agreement with underground nuclear explosive and high-power laser experimental results up to ~20 Mbar. The calculated viscosity and self-diffusion coefficients are compared with the one-component plasma model, using effective charges given by the average-atom model. The Stokes-Einstein relationship, which connects viscosity and self-diffusion coefficients, is found to hold fairly well in the strong coupling regime. The Lorenz number, which is the ratio between thermal and electrical conductivities, is computed via Kubo-Greenwood formula and compared to the well-known Wiedemann-Franz law in the warm dense region.

  18. Decay of Langmuir wave in dense plasmas and warm dense matter

    CERN Document Server

    Son, S; Moon, Sung Joon

    2010-01-01

    The decays of the Langmuir waves in dense plasmas are computed using the dielectric function theory widely used in the solid state physics. Four cases are considered: a classical plasma, a Maxwellian plasma, a degenerate quantum plasma, and a partially degenerate plasma. The result is considerably different from the conventional Landau damping theory.

  19. Variational Average-Atom in Quantum Plasmas (VAAQP) - Recent progress, virial theorem and applications to the equation-of-state of warm dense Be

    Science.gov (United States)

    Piron, R.; Blenski, T.

    2011-12-01

    The Variational Average-Atom in Quantum Plasmas (VAAQP) code is based on a fully variational theory of dense plasmas in equilibrium in which the neutrality of the Wigner-Seitz ion sphere is not required, contrary to the INFERNO model. We report on some recent progress in the VAAQP model and numerical code. Three important points of the virial theorem derivation are emphasized and explained. The virial theorem is also used as an important tool allowing us to check the formulas and numerical methods used in the code. Applications of the VAAQP code are shown using as an example the equation-of-state of beryllium in the warm dense matter regime. Comparisons with the INFERNO model, and with available experimental data on the principal Hugoniot are also presented.

  20. Evolution of Elastic X-ray Scattering in Laser-Shocked Warm Dense Li

    Energy Technology Data Exchange (ETDEWEB)

    Kugland, N L; Gregori, G; Bandyopadhyay, S; Brenner, C; Brown, C; Constantin, C; Glenzer, S H; Khattak, F; Kritcher, A L; Niemann, C; Otten, A; Pasley, J; Pelka, A; Roth, M; Spindloe, C; Riley, D

    2009-06-02

    We have studied the dynamics of warm dense Li with near-elastic x-ray scattering. Li foils were heated and compressed using shock waves driven by 4 ns long laser pulses. Separate 1 ns long laser pulses were used to generate a bright source of 2.96 keV Cl Ly-{alpha} photons for x-ray scattering, and the spectrum of scattered photons was recorded at a scattering angle of 120{sup o} using a HOPG crystal operated in the von Hamos geometry. A variable delay between the heater and backlighter laser beams measured the scattering time evolution. Comparison with radiation hydrodynamics simulations shows that the plasma is highly coupled during the first several nanoseconds, then relaxes to a moderate coupling state at later times. Near-elastic scattering amplitudes have been successfully simulated using the screened one-component plasma model. Our main finding is that the near-elastic scattering amplitudes are quite sensitive to the mean ionization state {bar Z}, and by extension to the choice of ionization model in the radiation-hydrodynamics simulations used to predict plasma properties within the shocked Li.

  1. The complex ion structure of warm dense carbon measured by spectrally resolved x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, D.; Barbrel, B.; Falcone, R. W. [Department of Physics, University of California, Berkeley, California 94720 (United States); Vorberger, J. [Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden (Germany); Helfrich, J.; Frydrych, S.; Ortner, A.; Otten, A.; Roth, F.; Schaumann, G.; Schumacher, D.; Siegenthaler, K.; Wagner, F.; Roth, M. [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstraße 9, 64289 Darmstadt (Germany); Gericke, D. O.; Wünsch, K. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Bachmann, B.; Döppner, T. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Bagnoud, V.; Blažević, A. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); and others

    2015-05-15

    We present measurements of the complex ion structure of warm dense carbon close to the melting line at pressures around 100 GPa. High-pressure samples were created by laser-driven shock compression of graphite and probed by intense laser-generated x-ray sources with photon energies of 4.75 keV and 4.95 keV. High-efficiency crystal spectrometers allow for spectrally resolving the scattered radiation. Comparing the ratio of elastically and inelastically scattered radiation, we find evidence for a complex bonded liquid that is predicted by ab-initio quantum simulations showing the influence of chemical bonds under these conditions. Using graphite samples of different initial densities we demonstrate the capability of spectrally resolved x-ray scattering to monitor the carbon solid-liquid transition at relatively constant pressure of 150 GPa. Showing first single-pulse scattering spectra from cold graphite of unprecedented quality recorded at the Linac Coherent Light Source, we demonstrate the outstanding possibilities for future high-precision measurements at 4th Generation Light Sources.

  2. Spin-resolved correlations in the warm-dense homogeneous electron gas

    Science.gov (United States)

    Arora, Priya; Kumar, Krishan; Moudgil, R. K.

    2017-04-01

    We have studied spin-resolved correlations in the warm-dense homogeneous electron gas by determining the linear density and spin-density response functions, within the dynamical self-consistent mean-field theory of Singwi et al. The calculated spin-resolved pair-correlation function gσσ'(r) is compared with the recent restricted path-integral Monte Carlo (RPIMC) simulations due to Brown et al. [Phys. Rev. Lett. 110, 146405 (2013)], while interaction energy Eint and exchange-correlation free energy Fxc with the RPIMC and very recent ab initio quantum Monte Carlo (QMC) simulations by Dornheim et al. [Phys. Rev. Lett. 117, 156403 (2016)]. g↑↓(r) is found to be in good agreement with the RPIMC data, while a mismatch is seen in g↑↑(r) at small r where it becomes somewhat negative. As an interesting result, it is deduced that a non-monotonic T-dependence of g(0) is driven primarily by g↑↓(0). Our results of Eint and Fxc exhibit an excellent agreement with the QMC study due to Dornheim et al., which deals with the finite-size correction quite accurately. We observe, however, a visible deviation of Eint from the RPIMC data for high densities ( 8% at rs = 1). Further, we have extended our study to the fully spin-polarized phase. Again, with the exception of high density region, we find a good agreement of Eint with the RPIMC data. This points to the need of settling the problem of finite-size correction in the spin-polarized phase also. Interestingly, we also find that the thermal effects tend to oppose spatial localization as well as spin polarization of electrons. Supplementary material in the form of one zip file available from the Journal web page at http://https://doi.org/10.1140/epjb/e2017-70532-y

  3. {\\em Ab initio} Quantum Monte Carlo simulation of the warm dense electron gas in the thermodynamic limit

    CERN Document Server

    Dornheim, Tobias; Sjostrom, Travis; Malone, Fionn D; Foulkes, W M C; Bonitz, Michael

    2016-01-01

    We perform \\emph{ab initio} quantum Monte Carlo (QMC) simulations of the warm dense uniform electron gas in the thermodynamic limit. By combining QMC data with linear response theory we are able to remove finite-size errors from the potential energy over the entire warm dense regime, overcoming the deficiencies of the existing finite-size corrections by Brown \\emph{et al.}~[PRL \\textbf{110}, 146405 (2013)]. Extensive new QMC results for up to $N=1000$ electrons enable us to compute the potential energy $V$ and the exchange-correlation free energy $F_{xc}$ of the macroscopic electron gas with an unprecedented accuracy of $|\\Delta V|/|V|, |\\Delta F_{xc}|/|F|_{xc} \\sim 10^{-3}$. A comparison of our new data to the recent parametrization of $F_{xc}$ by Karasiev {\\em et al.} [PRL {\\bf 112}, 076403 (2014)] reveals significant inaccuracies of the latter.

  4. The LZ dark matter experiment

    Science.gov (United States)

    McKinsey, D. N.; LZ Collaboration

    2016-05-01

    The LUX and ZEPLIN collaborations have merged to construct a 7 tonne two-phase Xe dark matter detector, known as LUX-ZEPLIN or LZ. Chosen as one of the Generation 2 suite of dark matter direct detection experiments, LZ will probe spin-independent WIMP-nucleon cross sections down to 2 × 10-48 cm2 at 50 GeV/c2 within 3 years of operation, covering a substantial range of theoretically-motivated dark matter candidates. Along with dark matter interactions with Xe nuclei, LZ will also be sensitive to solar neutrinos emitted by the pp fusion process in the sun, neutrinos emitted by a nearby supernova and detected by coherent neutrino-nucleus scattering, certain classes of axions and axion-like particles, and neutrinoless double-beta decay of 136Xe. The design of LZ is presented, along with its expected backgrounds and projected sensitivity.

  5. The DAMIC Dark Matter Experiment

    Energy Technology Data Exchange (ETDEWEB)

    de Mello Neto, J. R.T. [Federal Univ. of Rio de Janeiro (Brazil). et al

    2015-10-07

    The DAMIC (DArk Matter In CCDs) experiment uses high-resistivity, scientific-grade CCDs to search for dark matter. The CCD’s low electronic noise allows an unprecedently low energy threshold of a few tens of eV; this characteristic makes it possible to detect silicon recoils resulting from interactions of low-mass WIMPs. In addition, the CCD’s high spatial resolution and the excellent energy response results in very effective background identification techniques. The experiment has a unique sensitivity to dark matter particles with masses below 10 GeV/c2. Previous results have motivated the construction of DAMIC100, a 100 grams silicon target detector currently being installed at SNOLAB. The mode of operation and unique imaging capabilities of the CCDs, and how they may be exploited to characterize and suppress backgrounds are discussed, as well as physics results after one year of data taking.

  6. Variational-average-atom-in-quantum-plasmas (VAAQP) code and virial theorem: Equation-of-state and shock-Hugoniot calculations for warm dense Al, Fe, Cu, and Pb

    Science.gov (United States)

    Piron, R.; Blenski, T.

    2011-02-01

    The numerical code VAAQP (variational average atom in quantum plasmas), which is based on a fully variational model of equilibrium dense plasmas, is applied to equation-of-state calculations for aluminum, iron, copper, and lead in the warm-dense-matter regime. VAAQP does not impose the neutrality of the Wigner-Seitz ion sphere; it provides the average-atom structure and the mean ionization self-consistently from the solution of the variational equations. The formula used for the electronic pressure is simple and does not require any numerical differentiation. In this paper, the virial theorem is derived in both nonrelativistic and relativistic versions of the model. This theorem allows one to express the electron pressure as a combination of the electron kinetic and interaction energies. It is shown that the model fulfills automatically the virial theorem in the case of local-density approximations to the exchange-correlation free-energy. Applications of the model to the equation-of-state and Hugoniot shock adiabat of aluminum, iron, copper, and lead in the warm-dense-matter regime are presented. Comparisons with other approaches, including the inferno model, and with available experimental data are given. This work allows one to understand the thermodynamic consistency issues in the existing average-atom models. Starting from the case of aluminum, a comparative study of the thermodynamic consistency of the models is proposed. A preliminary study of the validity domain of the inferno model is also included.

  7. Variational-average-atom-in-quantum-plasmas (VAAQP) code and virial theorem: equation-of-state and shock-Hugoniot calculations for warm dense Al, Fe, Cu, and Pb.

    Science.gov (United States)

    Piron, R; Blenski, T

    2011-02-01

    The numerical code VAAQP (variational average atom in quantum plasmas), which is based on a fully variational model of equilibrium dense plasmas, is applied to equation-of-state calculations for aluminum, iron, copper, and lead in the warm-dense-matter regime. VAAQP does not impose the neutrality of the Wigner-Seitz ion sphere; it provides the average-atom structure and the mean ionization self-consistently from the solution of the variational equations. The formula used for the electronic pressure is simple and does not require any numerical differentiation. In this paper, the virial theorem is derived in both nonrelativistic and relativistic versions of the model. This theorem allows one to express the electron pressure as a combination of the electron kinetic and interaction energies. It is shown that the model fulfills automatically the virial theorem in the case of local-density approximations to the exchange-correlation free-energy. Applications of the model to the equation-of-state and Hugoniot shock adiabat of aluminum, iron, copper, and lead in the warm-dense-matter regime are presented. Comparisons with other approaches, including the inferno model, and with available experimental data are given. This work allows one to understand the thermodynamic consistency issues in the existing average-atom models. Starting from the case of aluminum, a comparative study of the thermodynamic consistency of the models is proposed. A preliminary study of the validity domain of the inferno model is also included.

  8. The DRIFT Dark Matter Experiments

    CERN Document Server

    Daw, E; Fox, J R; Gauvreau, J -L; Ghag, C; Harmon, L J; Harton, J L; Gold, M; Lee, E R; Loomba, D; Miller, E H; Murphy, A St J; Paling, S M; Landers, J M; Phan, N; Pipe, M; Pushkin, K; Robinson, M; Sadler, S W; Snowden-Ifft, D P; Spooner, N J C; Walker, D; Warner, D

    2011-01-01

    The current status of the DRIFT (Directional Recoil Identification From Tracks) experiment at Boulby Mine is presented, including the latest limits on the WIMP spin-dependent cross-section from 1.5 kg days of running with a mixture of CS2 and CF4. Planned upgrades to DRIFT IId are detailed, along with ongoing work towards DRIFT III, which aims to be the world's first 10 m3-scale directional Dark Matter detector.

  9. Revisiting metallization boundary of warm dense helium in a wide ρ-T regime from ab initio study

    Science.gov (United States)

    Zhang, Wei; Li, Zhiguo; Fu, Zhijian; Dai, Jiayu; Chen, Qifeng; Cai, Lingcang

    2017-02-01

    The knowledge of the metallization of warm dense helium has important implications for understanding the thermal histories, stellar structure and magnetic field environment of giant planets. However, it is also a pendent scientific topic. For a revisiting into the properties of warm dense helium, we performed extensive quantum Langevin molecular dynamic simulations and electronic structure calculations to study helium over a very wide range of density (ρ = 1~24 g/cm3) and temperature (T = 10~160 kK). The dependencies of helium band gap on ρ and T were presented and a metallization boundary of helium was thus determined by gap closure. Such a boundary is further identified by the calculated electrical conductivity and optical reflectivity based on Kubo-Greenwood formula: along the boundary, the electrical conductivities are found to be 7.0 × 105~1.3 × 106 Ω‑1 m‑1 and the optical reflectivity value at 532 nm is about 0.55, which are typical values for true metal.

  10. DEAP-3600 dark matter experiment

    CERN Document Server

    Fatemighomi, Nasim

    2016-01-01

    DEAP-3600 is a single phase liquid argon (LAr) dark matter experiment, located 2 km underground at SNOLAB, in Sudbury, Canada. The detector has 1 tonne fiducial mass of LAr. The target sensitivity to spin-independent scattering of 100 GeV weakly interacting massive particles (WIMPs) is 10$^{-46}$ cm$^{2}$. The DEAP-3600 background target is $<$ 0.6 background events in the WIMP region of interest in 3 tonne-years. The strategies to achieve this background include pulse shape discrimination to mitigate electron recoil and using ultra low radioactive materials for detector construction. Furthermore, to reduce neutron and alpha backgrounds, the DEAP-3600 acrylic vessel was sanded in situ to mitigate radon exposure of surfaces during construction and fabrication. The experiment is currently in the commissioning phase and will begin physics data taking later this year. This paper presents an overview of the experiment, its cross-section sensitivity to WIMPs and its current status.

  11. Results of the upgraded Neutralized Drift Compression Experiment

    Science.gov (United States)

    Lidia, Steven M.; Bieniosek, F. M.; Gilson, E. P.; Roy, P. K.; Ni, P.; Seidl, P. A.; van den Bogert, K.; Waldron, W. L.

    2009-11-01

    Recent changes to the NDCX beamline offer the promise of higher current compressed bunches, with correspondingly greater fluence delivered to the target plane for ion-beam driven warm dense matter experiments. We report modeling and commissioning results of the upgraded NDCX beamline that includes a new induction bunching module with approximately twice the volt-seconds and greater tuning flexibility, combined with a longer neutralized drift compression channel.

  12. X-ray scattering as a probe for warm dense mixtures and high-pressure miscibility

    CERN Document Server

    Wünsch, K; Gregori, G; Gericke, D O

    2010-01-01

    We demonstrate the abilities of elastic x-ray scattering to yield information on dense matter with multiple ion species and on the microscopic mixing in dense materials. Based on partial structure factors from ab initio simulations, a novel approach for the elastic scattering feature is applied to dense hydrogen-beryllium and hydrogen-helium mixtures. The scattering signal differs significantly between single species, real microscopic mixtures, and two separate fluids in the scattering volume.

  13. Solenoid transport of a heavy ion beam for warm dense matterstudies and inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Armijo, Julien

    2006-10-01

    From February to July 2006, I have been doing research as a guest at Lawrence Berkeley National Laboratory (LBNL), in the Heavy Ion Fusion group. This internship, which counts as one semester in my master's program in France, I was very pleased to do it in a field that I consider has the beauty of fundamental physics, and at the same time the special appeal of a quest for a long-term and environmentally-respectful energy source. During my stay at LBNL, I have been involved in three projects, all of them related to Neutralized Drift Compression Experiment (NDCX). The first one, experimental and analytical, has consisted in measuring the effects of the eddy currents induced by the pulsed magnets in the conducting plates of the source and diagnostic chambers of the Solenoid Transport Experiment (STX, which is a subset of NDCX). We have modeled the effect and run finite-element simulations that have reproduced the perturbation to the field. Then, we have modified WARP, the Particle-In-Cell code used to model the whole experiment, in order to import realistic fields including the eddy current effects and some details of each magnet. The second project has been to take part in a campaign of WARP simulations of the same experiment to understand the leakage of electrons that was observed in the experiment as a consequence to some diagnostics and the failure of the electrostatic electron trap. The simulations have shown qualitative agreement with the measured phenomena, but are still in progress. The third project, rather theoretical, has been related to the upcoming target experiment of a thin aluminum foil heated by a beam to the 1-eV range. At the beginning I helped by analyzing simulations of the hydrodynamic expansion and cooling of the heated material. But, progressively, my work turned into making estimates for the nature of the liquid/vapor two-phase flow. In particular, I have been working on criteria and models to predict the formation of droplets, their size

  14. Thermoelectric transport properties of warm dense molybdenum from first-principles simulations

    Science.gov (United States)

    French, Martin; Haill, Thomas; Desjarlais, Michael; Mattsson, Thomas

    2013-10-01

    Molybdenum, with its high melting point, significant electrical conductivity, and high material strength, is a technologically important material in general and has in particular recently been proposed as a driver material in high-pressure strength experiments on Sandia's Z-machine. To simulate and understand the processes in these experiments with magneto-hydrodynamic simulations, accurate models for the electrical and thermal conductivity are needed for a wide range of thermodynamic parameters. Here, we present novel results for the electrical and thermal conductivity of molybdenum in various states ranging from the solid to the dense plasma phase. The results were obtained with first-principles simulation techniques that combine density functional theory with molecular dynamics and linear response theory. We find good agreement between our theoretical results and available experimental data. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.

  15. Thermal conduction study of warm dense aluminum by proton differential heating

    Science.gov (United States)

    Ping, Y.; Kemp, G.; McKelvey, A.; Fernandez-Panella, A.; Shepherd, R.; Collins, G.; Sio, H.; King, J.; Freeman, R.; Hua, R.; McGuffey, C.; Kim, J.; Beg, F.

    2016-10-01

    A differential heating platform has been developed for thermal conduction study (Ping et al. PoP 2015), where a temperature gradient is induced and subsequent heat flow is probed by time-resolved diagnostics. An experiment using proton differential heating has been carried out at Titan laser for Au/Al targets. Two single-shot time-resolved diagnostics are employed, SOP (streaked optical pyrometry) for surface temperature and FDI (Fourier Domain Interferometry) for surface expansion. Hydrodynamic simulations show that after 15ps, absorption in underdense plasma needs to be taken into account to correctly interpret SOP data. Comparison between simulations with different thermal conductivity models and a set of data with varying target thickness will be presented. This work was performed under DOE contract DE-AC52-07NA27344 with support from OFES Early Career program and LLNL LDRD program.

  16. DAMIC: a novel dark matter experiment

    CERN Document Server

    Aguilar-Arevalo, Alexis A; Butner, Melissa J; Cancelo, Gustavo; Chavarria, Alvaro; D'Olivo, Juan Carlos; Vigil, Juan Cruz Estrada; Moroni, Guillermo Fernandez; Izraelevitch, Federico; Kilminster, Ben; Lawson, Ian T; Marsal, Fernando; Molina, Jorge; Privitera, Paolo; Schwarz, Tom; Haro, Miguel Sofo; Tiffenberg, Javier; Trillaud, Frederic; Zhou, Jing

    2013-01-01

    DAMIC (Dark Matter in CCDs) is a novel dark matter experiment that has unique sensitivity to dark matter particles with masses below 10 GeV. Due to its low electronic readout noise (R.M.S. ~3 e-) this instrument is able to reach a detection threshold below 0.5 keV nuclear recoil energy, making the search for dark matter particles with low masses possible. We report on early results and experience gained from a detector that has been running at SNOLAB from Dec 2012. We also discuss the measured and expected backgrounds and present the plan for future detectors to be installed in 2014.

  17. DAMIC: a novel dark matter experiment

    Energy Technology Data Exchange (ETDEWEB)

    Tiffenberg, Javier; Bertou, Xavier [Centro Atomico Bariloche; Butner, Melissa J. [Fermilab; Cancelo, Gustavo [Fermilab; Chavarria, Alvaro [Chicago U., KICP; D' Olivo, Juan Carlos [Mexico U., ICN; Estrada Vigil, Juan Cruz [Fermilab; Moroni, Guillermo Fernandez [Bahia Blanca, U. Natl. Del Sur; Izraelevitch, Federico [Fermilab; Kilminster, Ben [Zurich U.; Lawson, Ian T. [SNOLAB, Lively; Marsal, Fernando [Asuncion Natl. U.; Molina, Jorge [Asuncion Natl. U.; Privitera, Paolo [Chicago U., KICP; Schwarz, Tom [Michigan U.; Sofo haro, Miguel [Centro Atomico Bariloche; Tiffenberg, Javier [Fermilab; Trillaud, Frederic [Mexico U.; Zhou, Jing [Chicago U., KICP

    2013-10-24

    DAMIC (Dark Matter in CCDs) is a novel dark matter experiment that has unique sensitivity to dark matter particles with masses below 10 GeV. Due to its low electronic readout noise (R.M.S. ~3 e-) this instrument is able to reach a detection threshold below 0.5 keV nuclear recoil energy, making the search for dark matter particles with low masses possible. We report on early results and experience gained from a detector that has been running at SNOLAB from Dec 2012. We also discuss the measured and expected backgrounds and present the plan for future detectors to be installed in 2014.

  18. Dark Matter and Experiments for its Identification

    Directory of Open Access Journals (Sweden)

    V. Singh

    2015-08-01

    Full Text Available After Fritz Zwicky, through various theoretical models, several dark matter events have been proposed. But none of them is yet discovered. Recent experiment shows that only around 5% of the total matters present in the whole universe are visual. Rest matter is still unknown to us by any present experimental tools. This leads that detection of dark matter is one of the very challenging & curios goal for experimental physicists. For the search of suitable dark matter candidates and for rear physics events, High Purity Germanium detectors, Spherical gaseous chamber detector and few more hybrid-detectors are suitable for these purposes. We proposed that any suitable detector hosted under deep sea water will be more effective than the under ground or mountain caverns.

  19. Dark matter direct-detection experiments

    Science.gov (United States)

    Marrodán Undagoitia, Teresa; Rauch, Ludwig

    2016-01-01

    In recent decades, several detector technologies have been developed with the quest to directly detect dark matter interactions and to test one of the most important unsolved questions in modern physics. The sensitivity of these experiments has improved with a tremendous speed due to a constant development of the detectors and analysis methods, proving uniquely suited devices to solve the dark matter puzzle, as all other discovery strategies can only indirectly infer its existence. Despite the overwhelming evidence for dark matter from cosmological indications at small and large scales, clear evidence for a particle explaining these observations remains absent. This review summarises the status of direct dark matter searches, focusing on the detector technologies used to directly detect a dark matter particle producing recoil energies in the keV energy scale. The phenomenological signal expectations, main background sources, statistical treatment of data and calibration strategies are discussed.

  20. Dark matter direct-detection experiments

    CERN Document Server

    Undagoitia, Teresa Marrodan

    2015-01-01

    In the past decades, several detector technologies have been developed with the quest to directly detect dark matter interactions and to test one of the most important unsolved questions in modern physics. The sensitivity of these experiments has improved with a tremendous speed due to a constant development of the detectors and analysis methods, proving uniquely suited devices to solve the dark matter puzzle, as all other discovery strategies can only indirectly infer its existence. Despite the overwhelming evidence for dark matter from cosmological indications at small and large scales, a clear evidence for a particle explaining these observations remains absent. This review summarises the status of direct dark matter searches, focussing on the detector technologies used to directly detect a dark matter particle producing recoil energies in the keV energy scale. The phenomenological signal expectations, main background sources, statistical treatment of data and calibration strategies are discussed.

  1. Boosted Dark Matter at Neutrino Experiments

    CERN Document Server

    Necib, Lina; Wongjirad, Taritree; Conrad, Janet M

    2016-01-01

    Current and future neutrino experiments can be used to discover dark matter, not only in searches for dark matter annihilating to neutrinos, but also in scenarios where dark matter itself scatters off Standard Model particles in the detector. In this work, we study the sensitivity of different neutrino detectors to a class of models called boosted dark matter, in which a subdominant component of a dark sector acquires a large Lorentz boost today through annihilation of a dominant component in a dark matter-dense region, such as the galactic center or dwarf spheroidal galaxies. This analysis focuses on the sensitivity of different neutrino detectors, specifically the Cherenkov-based Super-K and the future argon-based DUNE to boosted dark matter that scatters off electrons. We study the dependence of the expected limits on the experimental features, such as energy threshold, volume and exposure in the limit of constant scattering amplitude. We highlight experiment-specific features that enable current and futur...

  2. The Light Dark Matter eXperiment

    Science.gov (United States)

    Colegrove, Owen; LDMX Collaboration

    2017-01-01

    The Light Dark Matter eXperiment (LDMX) proposes a high-statistics search for low-mass dark matter at a new experimental facility, Dark Sector Experiments at LCLS-II (DASEL), at SLAC. LDMX employs the missing momentum technique, where electrons scattering in a thin target can produce dark matter via ``dark bremsstrahlung'' that are not observed in the detector. To identify these rare signal events, LDMX individually tags incoming beam-energy electrons, unambiguously associates them with low energy, moderate transverse-momentum recoils of the incoming electron, and establishes the absence of any additional forward-recoiling charged particles or neutral hadrons. LDMX will employ low mass tracking to tag incoming beam-energy electrons with high purity and cleanly reconstruct recoils. A high-speed, granular calorimeter with MIP sensitivity is used to reject the high rate of bremsstrahlung background at trigger level while working in tandem with a hadronic calorimeter to veto rare photo nuclear reactions. Ultimately, LDMX aims to probe thermal dark matter over most of the viable sub-GeV mass range to a decisive level of sensitivity. This talk will summarize the current status of the LDMX design and performance studies and progress in developing the DASEL beamline.

  3. The XENONnT Dark Matter Experiment

    Science.gov (United States)

    Aprile, Elena; Xenon Collaboration

    2017-01-01

    With XENON1T ready to search for dark matter with the highest sensivity of any experiment to-date the XENON collaboration started to secure funding and resources to upgrade the detector by the end of 2018- phase which we refer to as XENONnT. The XENONnT experiment will utilize the already-built-and-tested XENON1T infrastructures, such as the cryogenic system, Kr distillation system and Xe storage and recovery system, with the main upgrade of the time projection chamber (TPC). The upgraded XENONnT detector will be filled with 7.5-ton ultra-pure liquid xenon, tripling the active liquid xenon target mass of XENON1T. About 500 low-radioactive three-inch R11410 PMTs will be used. Background from internal sources such as radon will be reduced. It will enable another order of magnitude improvement in dark matter search sensitivity compared to that of XENON1T, or accumulate statistics if a positive dark matter signal is observed by XENON1T. The detailed TPC upgrade plan, the background control and reduction techniques, the predicted sensitivity reach will be presented.

  4. The Compressed Baryonic Matter Experiment at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Heuser, Johann M.

    2013-05-02

    The Compressed Baryonic Matter (CBM) experiment will explore the phase diagram of strongly interacting matter in the region of high net baryon densities. The experiment is being laid out for nuclear collision rates from 0.1 to 10 MHz to access a unique wide spectrum of probes, including rarest particles like hadrons containing charm quarks, or multi-strange hyperons. The physics programme will be performed with ion beams of energies up to 45 GeV/nucleon. Those will be delivered by the SIS-300 synchrotron at the completed FAIR accelerator complex. Parts of the research programme can already be addressed with the SIS-100 synchrotron at the start of FAIR operation in 2018. The initial energy range of up to 11 GeV/nucleon for heavy nuclei, 14 GeV/nucleon for light nuclei, and 29 GeV for protons, allows addressing the equation of state of compressed nuclear matter, the properties of hadrons in a dense medium, the production and propagation of charm near the production threshold, and exploring the third, strange dimension of the nuclide chart. In this article we summarize the CBM physics programme, the preparation of the detector, and give an outline of the recently begun construction of the Facility for Antiproton and Ion Research.

  5. The MiniCLEAN Dark Matter Experiment

    CERN Document Server

    Hime, Andrew

    2011-01-01

    The MiniCLEAN dark matter experiment will exploit a single-phase liquid-argon detector instrumented with photomultiplier tubes submerged in the cryogen with nearly 4pi coverage of a 500 kg (150 kg) target (fiducial) mass. The high light yield and unique properties of the scintillation time-profile provide effective defense against radioactive background through pulse-shape discrimination and event-position reconstruction. The detector is designed also for a liquid-neon target that allows for an independent verification of signal and background and a test of the expected dependence of the WIMP-nucleus interaction rate.

  6. The DEAP-3600 Dark Matter Experiment

    CERN Document Server

    ,

    2015-01-01

    The DEAP-3600 experiment uses 3.6 tons of liquid argon for a sensitive dark matter search, with a sensitivity to the spin-independent WIMP-nucleon cross-section of $10^{-46}$ cm$^2$ at 100 GeV WIMP mass. This high sensitivity is achievable due to the large target mass and the very low backgrounds in the spherical acrylic detector design as well as at the unique SNOLAB facility in Sudbury, Canada. Pulse shape discrimination is used to reject electromagnetic backgrounds from the WIMP induced nuclear recoil signal. We started taking commissioning data in early 2015 with vacuum and later gas inside the detector. Argon fill is expected in winter 2015. An overview and status of the DEAP-3600 experiment are presented in this paper, with an emphasis on control and mitigation of detector backgrounds.

  7. Simultaneous induction acceleration and bunching in the Neutralized Drift Compression Experiment

    Science.gov (United States)

    Seidl, Peter; Bazouin, G.; Lidia, S. M.; Roy, P. K.; Waldron, W. L.

    2009-11-01

    The Neutralized Drift Compression Experiment uses a ramped, bipolar induction module waveform to compress the beam to nanosecond bunches for the study of warm dense matter (WDM). We have recently explored beam dynamics and possible beamline modifications required to simultaneously compress and accelerate the beam using a unipolar waveform. This has the advantage of a higher energy deposition in the target, and mimics beam manipulations in next-generation ion accelerators for WDM experiments. We report modeling and experimental results of this beam manipulation on the NDCX beamline with the new induction bunching module with approximately twice the volt-seconds.

  8. STATUS OF THE NEUTRALIZED DRIFT COMPRESSION EXPERIMENT (NDCX-II)

    Energy Technology Data Exchange (ETDEWEB)

    Waldron, W.L.; Kwan, J.W.

    2011-04-21

    The Neutralized Drift Compression Experiment (NDCX-II) is an 11 M$ induction accelerator project currently in construction at Lawrence Berkeley National Laboratory for warm dense matter (WDM) experiments investigating the interaction of ion beams with matter at elevated temperature and pressure. The machine consists of a lithium injector, induction accelerator cells, diagnostic cells, a neutralized drift compression line, a final focus solenoid, and a target chamber. The induction cells and some of the pulsed power systems have been reused from the decommissioned Advanced Test Accelerator at Lawrence Livermore National Laboratory after refurbishment and modification. The machine relies on a sequence of acceleration waveforms to longitudinally compress the initial ion pulse from 600 ns to less than 1 ns in {approx} 12 m. Radial confinement of the beam is achieved with 2.5 T pulsed solenoids. In the initial hardware configuration, 50 nC of Li{sup +} will be accelerated to 1.25 MeV and allowed to drift-compress to a peak current of {approx}40 A. The project started in the summer of 2009. Construction of the accelerator will be completed in the fall of 2011 and will provide a worldwide unique opportunity for ion-driven warm dense matter experiments as well as research related to novel beam manipulations for heavy ion fusion drivers.

  9. Results from the LUX dark matter experiment

    Energy Technology Data Exchange (ETDEWEB)

    Horn, Markus, E-mail: markus.horn@yale.edu [Yale University, Dept. of Physics, 217 Prospect St., New Haven CT 06511 (United States); Akerib, D.S [Case Western Reserve University, Dept. of Physics, 10900 Euclid Ave, Cleveland, OH 44106 (United States); Araújo, H.M. [Imperial College London, High Energy Physics, Blackett Laboratory, London SW7 2BZ (United Kingdom); Bai, X. [South Dakota School of Mines and Technology, 501 East St Joseph St., Rapid City SD 57701 (United States); Bailey, A.J. [Imperial College London, High Energy Physics, Blackett Laboratory, London SW7 2BZ (United Kingdom); Balajthy, J. [University of Maryland, Dept. of Physics, College Park, MD 20742 (United States); Bernard, E. [Yale University, Dept. of Physics, 217 Prospect St., New Haven CT 06511 (United States); Bernstein, A. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94551 (United States); Bradley, A. [Case Western Reserve University, Dept. of Physics, 10900 Euclid Ave, Cleveland, OH 44106 (United States); Byram, D. [University of South Dakota, Dept. of Physics, 414E Clark St., Vermillion, SD 57069 (United States); Cahn, S.B. [Yale University, Dept. of Physics, 217 Prospect St., New Haven CT 06511 (United States); Carmona-Benitez, M.C. [University of California Santa Barbara, Dept. of Physics, Santa Barbara, CA (United States); Chan, C.; Chapman, J.J. [Brown University, Dept. of Physics, 182 Hope St., Providence, RI 02912 (United States); Chiller, A.A.; Chiller, C. [University of South Dakota, Dept. of Physics, 414E Clark St., Vermillion, SD 57069 (United States); Currie, A. [Imperial College London, High Energy Physics, Blackett Laboratory, London SW7 2BZ (United Kingdom); Viveiros, L. de [LIP-Coimbra, Department of Physics, University of Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); Dobi, A. [University of Maryland, Dept. of Physics, College Park, MD 20742 (United States); and others

    2015-06-01

    The LUX (Large Underground Xenon) experiment aims at the direct detection of dark matter particles via their collisions with xenon nuclei. The 370 kg two-phase liquid xenon time projection chamber measures simultaneously the scintillation and ionization from interactions in the target. The ratio of these two signals provides very good discrimination between potential nuclear recoil and electronic recoil signals to search for WIMP-nucleon scattering. The LUX detector operates at the Sanford Underground Research Facility (Lead, South Dakota, USA) since February 2013. First results were presented in late 2013 setting the world's most stringent limits on WIMP-nucleon scattering cross-sections over a wide range of WIMP masses. A 300 day run beginning in 2014 will further improve the sensitivity and new calibration techniques will reduce systematics for the WIMP signal search.

  10. Revisiting First-Year College Students' Mattering: Social Support, Academic Stress, and the Mattering Experience

    Science.gov (United States)

    Rayle, Andrea Dixon; Chung, Kuo-Yi

    2008-01-01

    In this study, Nancy Schlossberg's (1989) theory of college students' mattering to others was revisited. Mattering is the experience of others depending on us, being interested in us, and being concerned with our fate. The relationships of gender, mattering to college friends and the college environment, and friend and family social support with…

  11. Dynamic properties of the energy loss of multi-MeV charged particles traveling in two-component warm dense plasmas

    Science.gov (United States)

    Fu, Zhen-Guo; Wang, Zhigang; Li, Meng-Lei; Li, Da-Fang; Kang, Wei; Zhang, Ping

    2016-12-01

    The energy loss of multi-MeV charged particles moving in two-component warm dense plasmas (WDPs) is studied theoretically beyond the random-phase approximation. The short-range correlations between particles are taken into account via dynamic local field corrections (DLFC) in a Mermin dielectric function for two-component plasmas. The mean ionization states are obtained by employing the detailed configuration accounting model. The Yukawa-type effective potential is used to derive the DLFC. Numerically, the DLFC are obtained via self-consistent iterative operations. We find that the DLFC are significant around the maximum of the stopping power. Furthermore, by using the two-component extended Mermin dielectric function model including the DLFC, the energy loss of a proton with an initial energy of ˜15 MeV passing through a WDP of beryllium with an electronic density around the solid value ne≈3 ×1023cm-3 and with temperature around ˜40 eV is estimated numerically. The numerical result is reasonably consistent with the experimental observations [A. B. Zylsta et al., Phys. Rev. Lett. 111, 215002 (2013), 10.1103/PhysRevLett.111.215002]. Our results show that the partial ionization and the dynamic properties should be of importance for the stopping of charged particles moving in the WDP.

  12. A simple and effective simulation for electrical conductivity of warm dense titanium%温稠密钛电导率计算

    Institute of Scientific and Technical Information of China (English)

    付志坚; 贾丽君; 夏继宏; 唐可; 李召红; 权伟龙; 陈其峰

    2016-01-01

    A linear mixture rule has been used to calculate the electrical conductivity of warm dense titanium plasmas in the density and temperature ranges of 10−5–10 g·cm−3 and 104–3 × 104 K, in which the interactions among electrons, atoms, and ions are considered systemically. In the first place, the coupling and degeneracy parameters of titanium plasma are shown as a function of density and temperature in the warm dense range. The warm dense titanium plasmas span from weakly coupled, nondegenerate region to strongly coupled, degenerate domain in the whole density and temperature regime. The titanium plasma becomes strongly coupled plasma at higher than 0.22 g·cm−3 and almost in the whole temperature range where the coupling parameter Γii > 1. In particular, the Coulomb interactions become stronger at higher than 0.56 g cm−3 where 10 1. The influence of temperature on the coupling and degeneracy parameters is less than that of the density, and the plasma composition is calculated by the nonideal Saha equation felicitously. Thus the ionization degree decreases with increasing density at lower density, which is due to the thermal ionization in that regime where the free electrons have sufficiently high thermal energy. Meanwhile, the ionization degree increases with the increase of density at higher than 0.1 g·cm−3, in which the pressure ionization takes place in the region where the electrons have sufficiently high density and the collisions increase rapidly. There is a minimum for the ionization degree at about 0.1 g·cm−3, while the maximum ionization degree reaches 4 at 10 g·cm−3. In the whole temperature regime, the titanium plasma is mostly in the partial plasma domain at lower than 1 g·cm−3, and becomes completely ionized at higher than 1 g·cm−3. The calculated conductivity is in reasonable agreement with the experimental data. At a fixed temperature, there is a minimum in each of the ionization curves at lower than 3 × 104 K. And the

  13. Generation of intense X-radiation and high-energy-density matter by laser-accelerated electrons; Erzeugung von intensiver Roentgenstrahlung und Materie hoher Energiedichte durch Laserbeschleunigte Elektronen

    Energy Technology Data Exchange (ETDEWEB)

    Schoenlein, Andreas

    2015-07-01

    Aim of this thesis was to study the processes of the interaction between highly intense short-pulse laser and matter. The focus lied thereby on the generation of intense X-radiation and warm dense matter. The studies performed for this thesis comprehend thereby the influence of laser parameters like energy, pulse length, focus size, and intensity as well as the influence of the target geometry on the interaction and generation of high-energy-density matter. In this thesis for this two selected experiments are presented. First a silver foil was used as target, in order to study the generation of radiation at 21 keV. Both bremsstrahlung and characteristic X-radiation were used in order to characterize the interaction. For the second experiment freely standing titanium wires were used as target. Hereby the focus lied on the characterization of the heated matter.

  14. Using XFELs for Probing of Complex Interaction Dynamics of Ultra-Intense Lasers with Solid Matter

    CERN Document Server

    Kluge, Thomas; Huang, Lingen; Metzkes, Josefine; Schramm, Ulrich; Bussmann, Michael; Cowan, Thomas E

    2013-01-01

    We demonstrate the potential of X-ray free-electron lasers (XFEL) to advancethe understanding of complex plasma dynamics by allowing for the first time nanometer and femtosecond resolution at the same time in plasma diagnostics. Plasma phenomena on such short timescales are of high relevance for many fields of physics, in particular in the ultra-intense ultra-short laser interaction with matter. Highly relevant yet only partially understood phenomena may become directly accessible in experiment. These include relativistic laser absorption at solid targets, creation of energetic electrons and electron transport in warm dense matter, including the seeding and development of surface and beam instabilities, ambipolar expansion, shock formation, and dynamics at the surfaces or at buried layers. We demonstrate the potentials of XFEL plasma probing for high power laser matter interactions using exemplary the small angle X-ray scattering technique, focusing on general considerations for XFEL probing.

  15. Review of dark matter direct detection experiments

    Indian Academy of Sciences (India)

    Rupak Mahapatra

    2012-11-01

    Matter, as we know it, makes up less than 5% of the Universe. Various astrophysical observations have confirmed that one quarter of the Universe and most of the matter content in the Universe is made up of dark matter. The nature of dark matter is yet to be discovered and is one of the biggest questions in physics. Particle physics combined with astrophysical measurements of the abundance gives rise to a dark matter candidate called weakly interacting massive particle (WIMP). The low density of WIMPs in the galaxies and the extremely weak nature of the interaction with ordinary matter make detection of the WIMP an extraordinarily challenging task, with abundant fakes from various radioactive and cosmogenic backgrounds with much stronger electromagnetic interaction. The extremely weak nature of the WIMP interaction dictates detectors that have extremely low naturally occurring radioactive background, a large active volume (mass) of sensitive detector material to maximize statistics, a highly efficient detector-based rejection mechanism for the dominant electromagnetic background and sophisticated analysis techniques to reject any residual background. This paper reviews currently available major technologies being pursued by various collaborations, with special emphasis on the cryogenic Ge detector technology used by the Cryogenic Dark Matter Search Collaboration (CDMS).

  16. Diagnostics for ion beam driven high energy density physics experiments.

    Science.gov (United States)

    Bieniosek, F M; Henestroza, E; Lidia, S; Ni, P A

    2010-10-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K(+) beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  17. The C-4 Dark Matter Experiment

    CERN Document Server

    Bonicalzi, R M; Colaresi, J; Fast, J E; Fields, N E; Fuller, E S; Hai, M; Hossbach, T W; Kos, M S; Orrell, J L; Overman, C T; Reid, D J; VanDevender, B A; Wiseman, C; Yocum, K M

    2012-01-01

    We describe the experimental design of C-4, an expansion of the CoGeNT dark matter search to four identical detectors each approximately three times the mass of the p-type point contact germanium diode presently taking data at the Soudan Underground Laboratory. Expected reductions of radioactive backgrounds and energy threshold are discussed, including an estimate of the additional sensitivity to low-mass dark matter candidates to be obtained with this search.

  18. The C-4 dark matter experiment

    Science.gov (United States)

    Bonicalzi, R. M.; Collar, J. I.; Colaresi, J.; Fast, J. E.; Fields, N. E.; Fuller, E. S.; Hai, M.; Hossbach, T. W.; Kos, M. S.; Orrell, J. L.; Overman, C. T.; Reid, D. J.; VanDevender, B. A.; Wiseman, C.; Yocum, K. M.

    2013-06-01

    We describe the experimental design of C-4, an expansion of the CoGeNT dark matter search to four identical detectors each approximately three times the mass of the p-type point contact germanium diode presently taking data at the Soudan Underground Laboratory. Expected reductions of radioactive backgrounds and energy threshold are discussed, including an estimate of the additional sensitivity to low-mass dark matter candidates to be obtained with this search.

  19. The Large Hadron Collider and the Super Proton Synchrotron at CERN as Tools to Generate Warm Dense Matter and Non–Ideal Plasmas

    CERN Document Server

    Tahir, N A; Shutov, A; Lomonosov, I V; Gryaznov, V; Piriz, A R; Deutsch, C; Fortov, V E

    2011-01-01

    The largest accelerator in the world, the Large Hadron Collider (LHC) at CERN, has entered into commission- ing phase. It is expected that when this impressive machine will become fully operational, it will generate two counter rotating 7 TeV/c proton beams that will be made to collide, leading to an unprecedented luminosity of 1034 cm−2s−1. Total energy stored in each LHC beam is about 362 MJ, sufficient to melt 500 kg copper. Safety of operation is a very critical issue when working with such extremely powerful beams. It is important to know the consequences of an accidental release of the beam energy in order to design protection system for the equipment. For this purpose we have carried out extensive numerical simulations of the interaction of one full LHC beam with copper and graphite targets which are materials of practical importance. Our calculations have shown that the LHC protons will penetrate up to about 35 m in solid copper and 10 m in solid graphite. A very interesting outcome of this work i...

  20. The Large Hadron Collider and the Super Proton Synchrotron at CERN as Tools to Generate Warm Dense Matter and Non-Ideal Plasmas

    CERN Document Server

    Tahir, N A; Deutsch, C; Gryaznov, V; Lomonosov, I V; Shutov, A; Piriz, A R; Fortov, V E; Geissel, H; Redmer, R

    2011-01-01

    The largest accelerator in the world, the Large Hadron Collider (LHC) at CERN, has entered into commissioning phase. It is expected that when this impressive machine will become fully operational, it will generate two counter rotating 7 TeV/c proton beams that will be made to collide, leading to an unprecedented luminosity of 10(34) cm(-2)s(-1). Total energy stored in each LHC beam is about 362 MJ, sufficient to melt 500 kg copper. Safety of operation is a very critical issue when working with such extremely powerful beams. It is important to know the consequences of an accidental release of the beam energy in order to design protection system for the equipment. For this purpose we have carried out extensive numerical simulations of the interaction of one full LHC beam with copper and graphite targets which are materials of practical importance. Our calculations have shown that the LHC protons will penetrate up to about 35 m in solid copper and 10 m in solid graphite. A very interesting outcome of this work i...

  1. Prospects of warm dense matter research at HiRadMat facility at CERN using 440 MeV SPS proton beam

    CERN Document Server

    Tahir, N A; Schmidt, R; Shutov, A; Piriz, A R

    2013-01-01

    In this paper we present numerical simulations of heating of a solid copper cylinder by the 440 GeV proton beam delivered by the Super Proton Synchrotron (SPS) at CERN. The beam is made of 288 proton bunches while each bunch comprises of 1.15$1011 so that the total number of protons in the beam is about 1.3$1013. The bunch length is 0.5 ns while two neighboring bunches are separated by 25 ns so that the beam duration is 7.2 ms. Particle intensity distribution in the transverse direction is a Gaussian and the beam can be focused to a spot size with s 1⁄4 0.1 mme1.0 mm. In this paper we present results using two values of s, namely 0.2 mm and 0.5 mm, respectively. The target length is 1.5 m with a radius 1⁄4 5 cm and is facially irradiated by the beam. The energy deposition code FLUKA and the two-dimensional hydrodynamic code BIG2 are employed using a suitable iteration time to simulate the hydrodynamic and the thermodynamic response of the target. The primary purpose of this work was to design fixed target...

  2. Direct detection experiments explained with mirror dark matter

    Science.gov (United States)

    Foot, R.

    2014-01-01

    Recently, the CDMS/Si experiment has observed a low energy excess of events in their dark matter search. In light of this new result we update the mirror dark matter explanation of the direction detection experiments. We find that the DAMA, CoGeNT, CRESST-II and CDMS/Si data can be simultaneously explained by halo ∼Fe‧ interactions provided that vrot≈200 km/s. Other parameter space is also possible. Forthcoming experiments, including CDMSlite, CDEX, COUPP, LUX, C-4, … should be able to further scrutinize mirror dark matter and closely related hidden sector models in the near future.

  3. Direct detection experiments explained with mirror dark matter

    CERN Document Server

    Foot, R

    2014-01-01

    Recently, the CDMS/Si experiment has observed a low energy excess of events in their dark matter search. In light of this new result we update the mirror dark matter explanation of the direction detection experiments. We find that the DAMA, CoGeNT, CRESST-II and CDMS/Si data can be simultaneously explained by halo $\\sim Fe'$ interactions provided that $v_{rot} \\approx 200$ km/s. Other parameter space is also possible. Forthcoming experiments, including CDMSlite, CDEX, COUPP, LUX, C-4,... should be able to further scrutinize mirror dark matter and closely related hidden sector models in the near future.

  4. Fundamental statistical limitations of future dark matter direct detection experiments

    NARCIS (Netherlands)

    Strege, C.; Trotta, F.; Bertone, G.; Peter, A.H.G.; Scott, P.

    2012-01-01

    We discuss irreducible statistical limitations of future ton-scale dark matter direct detection experiments. We focus in particular on the coverage of confidence intervals, which quantifies the reliability of the statistical method used to reconstruct the dark matter parameters and the bias of the r

  5. The Adolescent Mattering Experience: Gender Variations in Perceived Mattering, Anxiety, and Depression

    Science.gov (United States)

    Dixon, Andrea L.; Scheidegger, Corey; McWhirter, J. Jeffries

    2009-01-01

    Individuals who perceive that they matter to others are likely to experience lower anxiety and depression levels. The effects of young adolescents' perceived mattering on their anxiety and depression levels were examined. Results indicated that female adolescents reported lower anxiety levels but greater depression levels than did male…

  6. Simulations and experiments of intense ion beam current density compression in space and timea)

    Science.gov (United States)

    Sefkow, A. B.; Davidson, R. C.; Gilson, E. P.; Kaganovich, I. D.; Anders, A.; Coleman, J. E.; Leitner, M.; Lidia, S. M.; Roy, P. K.; Seidl, P. A.; Waldron, W. L.; Yu, S. S.; Welch, D. R.

    2009-05-01

    The Heavy Ion Fusion Science Virtual National Laboratory has achieved 60-fold longitudinal pulse compression of ion beams on the Neutralized Drift Compression Experiment (NDCX) [P. K. Roy et al., Phys. Rev. Lett. 95, 234801 (2005)]. To focus a space-charge-dominated charge bunch to sufficiently high intensities for ion-beam-heated warm dense matter and inertial fusion energy studies, simultaneous transverse and longitudinal compression to a coincident focal plane is required. Optimizing the compression under the appropriate constraints can deliver higher intensity per unit length of accelerator to the target, thereby facilitating the creation of more compact and cost-effective ion beam drivers. The experiments utilized a drift region filled with high-density plasma in order to neutralize the space charge and current of an ˜300 keV K+ beam and have separately achieved transverse and longitudinal focusing to a radius 2 MeV) ion beam user-facility for warm dense matter and inertial fusion energy-relevant target physics experiments.

  7. Dark Matter Searches and Prospects at the ATLAS Experiment

    CERN Document Server

    Taylor, Wendy; The ATLAS collaboration

    2017-01-01

    Despite the recent discovery of the Higgs boson contributing to the success of the Standard Model, the large excess of dark matter in the Universe remains one of the outstanding questions in science. This excess cannot be explained by Standard Model particles. A compelling hypothesis is that dark matter comprises particles that can be produced at the LHC, called Weakly Interacting Massive Particles (WIMPs). This talk presents a number of ATLAS searches for WIMP dark matter, outlining the main theoretical benchmarks and issues in terms of complementarity with direct and indirect detection experiments, and presents the prospects for dark matter searches at future LHC runs.

  8. Dark matter at the SHiP experiment

    Directory of Open Access Journals (Sweden)

    Timiryasov Inar

    2016-01-01

    Full Text Available We study prospects of dark matter searches in the SHiP experiment. SHiP (Search for Hidden Particles is the recently proposed fixed target experiment which will exploit the high-intensity beam of 400 GeV protons from the CERN SPS. In addition to the hidden sector detector, SHiP will be equipped with the ντ detector, which presumably would be sensitive to dark matter particles. We describe appropriate production and detection channels and estimate SHiP’s sensitivity for a scalar dark matter coupled to the Standard model through the vector mediator.

  9. The Cryogenic Dark Matter Search low ionization-threshold experiment

    Energy Technology Data Exchange (ETDEWEB)

    Basu Thakur, Ritoban [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2014-01-01

    Over 80 years ago we discovered the presence of Dark Matter in our universe. Endeavors in astronomy and cosmology are in consensus with ever improving precision that Dark Matter constitutes an essential 27% of our universe. The Standard Model of Particle Physics does not provide any answers to the Dark Matter problem. It is imperative that we understand Dark Matter and discover its fundamental nature. This is because, alongside other important factors, Dark Matter is responsible for formation of structure in our universe. The very construct in which we sit is defined by its abundance. The Milky Way galaxy, hence life, wouldn't have formed if small over densities of Dark Matter had not caused sufficient accretion of stellar material. Marvelous experiments have been designed based on basic notions to directly and in-directly study Dark Matter, and the Cryogenic Dark Matter Search (CDMS) experiment has been a pioneer and forerunner in the direct detection field. Generations of the CDMS experiment were designed with advanced scientific upgrades to detect Dark Matter particles of mass O(100) GeV/c2. This mass-scale was set primarily by predictions from Super Symmetry. Around 2013 the canonical SUSY predictions were losing some ground and several observations (rather hints of signals) from various experiments indicated to the possibility of lighter Dark Matter of mass O(10) GeV/c2. While the SuperCDMS experiment was probing the regular parameter space, the CDMSlite experiment was conceived to dedicatedly search for light Dark Matter using a novel technology. "CDMSlite" stands for CDMS - low ionization threshold experiment. Here we utilize a unique electron phonon coupling mechanism to measure ionization generated by scattering of light particles. Typically signals from such low energy recoils would be washed under instrumental noise. In CDMSlite via generation of Luke-Neganov phonons we can detect the small ionization energies, amplified in

  10. Validity - a matter of resonant experience

    DEFF Research Database (Denmark)

    Revsbæk, Line

    across researcher’s past experience from the case study and her own life. The autobiographic way of analyzing conventional interview material is exemplified with a case of a junior researcher researching newcomer innovation of others, drawing on her own experience of being newcomer in work community...

  11. Capturing experience: a matter of contextualising events

    NARCIS (Netherlands)

    Nack, F.-M.

    2004-01-01

    This paper explores the notion of experience in the context of dynamic and interactive environments, such as web-based musea, where neither the individual user requirements nor the requested material can be predicted in advance. A definition of experiences for the particular context is introduced on

  12. Capturing experience - a matter of contextualising events

    NARCIS (Netherlands)

    Nack, F.-M.

    2003-01-01

    This paper explores the notion of experience in the context of dynamic and interactive environments, such as web-based musea, where neither the individual user requirements nor the requested material can be predicted in advance. A definition of experiences for the particular context is introduced on

  13. Exploring Mbar shock conditions and isochorically heated aluminum at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, L. B. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Physics Department, University of California Berkeley, Berkeley, California 94709 (United States); Lee, H. J.; Gauthier, M.; Galtier, E.; Nagler, B.; Heimann, P.; Hastings, J. B.; Glenzer, S. H. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Barbrel, B.; Falcone, R. W. [Physics Department, University of California Berkeley, Berkeley, California 94709 (United States); Döppner, T.; LePape, S.; Ma, T.; Pak, A.; Turnbull, D. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); White, T.; Gregori, G. [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Wei, M. [General Atomics, San Diego, California 87544 (United States); Zastrau, U. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Institute for Optics and Quantum Electronics, Friedrich-Schiller-University, 07743 Jena (Germany)

    2014-11-15

    Recent experiments performed at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (LCLS) have demonstrated the first spectrally resolved measurements of plasmons from isochorically heated aluminum. The experiments have been performed using a seeded 8-keV x-ray laser beam as a pump and probe to both volumetrically heat and scatter x-rays from aluminum. Collective x-ray Thomson scattering spectra show a well-resolved plasmon feature that is down-shifted in energy by 19 eV. In addition, Mbar shock pressures from laser-compressed aluminum foils using velocity interferometer system for any reflector have been measured. The combination of experiments fully demonstrates the possibility to perform warm dense matter studies at the LCLS with unprecedented accuracy and precision.

  14. An Overview of Dark Matter Experiments at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    James Boyce

    2012-09-01

    Dark Matter research at Jefferson Lab started in 2006 with the LIght Pseudoscalar and Scalar Search (LIPSS) collaboration to check the validity of results reported by the PVLAS collaboration. In the intervening years interest in dark matter laboratory experiments has grown at Jefferson Lab. Current research underway or in planning stages probe various mass regions covering 14 orders of magnitude: from 10{sup -6} eV to 100 MeV. This presentation will be an overview of our dark matter efforts, three of which focus on the hypothesized A' gauge boson.

  15. Why Death Matters: Understanding Gameworld Experience

    Directory of Open Access Journals (Sweden)

    Lisbeth Klastrup

    2007-06-01

    Full Text Available This article presents a study of the staging and implementation of death and the death penalty in a number of popular MMOGs and relates it to players general experience of gameworlds. Game mechanics, writings and stories by designers and players, and the results of an online survey are analysed and discussed. The study shows that the death penalty is implemented much in the same way across worlds; that death can be both trivial and non-trivial, part of the grind of everyday life, or essential in the creation of heroes, depending on context. In whatever function death may serves, it is argued that death plays an important part in the shaping and emergence of the social culture of a world, and in the individual players experience of life within it.

  16. Dark matter effective field theory scattering in direct detection experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schneck, K.; Cabrera, B.; Cerdeno, D. G.; Mandic, V.; Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins, R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, Priscilla B.; Daal, M.; Di Stefano, P. C.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, Jeter C.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, W.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.

    2015-05-01

    We examine the consequences of the effective eld theory (EFT) of dark matter-nucleon scattering or current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral di*erences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.

  17. Dark matter effective field theory scattering in direct detection experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schneck, K.; Cabrera, B.; Cerdeño, D. G.; Mandic, V.; Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins, R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.

    2015-05-18

    We examine the consequences of the effective field theory (EFT) of dark matter-nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. Here. we demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. In conclusion, we discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.

  18. Dark matter effective field theory scattering in direct detection experiments

    CERN Document Server

    Schneck, K; Cerdeno, D G; Mandic, V; Rogers, H E; Agnese, R; Anderson, A J; Asai, M; Balakishiyeva, D; Barker, D; Thakur, R Basu; Bauer, D A; Billard, J; Borgland, A; Brandt, D; Brink, P L; Bunker, R; Caldwell, D O; Calkins, R; Chagani, H; Chen, Y; Cooley, J; Cornell, B; Crewdson, C H; Cushman, P; Daal, M; Di Stefano, P C F; Doughty, T; Esteban, L; Fallows, S; Figueroa-Feliciano, E; Godfrey, G L; Golwala, S R; Hall, J; Harris, H R; Hofer, T; Holmgren, D; Hsu, L; Huber, M E; Jardin, D M; Jastram, A; Kamaev, O; Kara, B; Kelsey, M H; Kennedy, A; Leder, A; Loer, B; Asamar, E Lopez; Lukens, P; Mahapatra, R; McCarthy, K A; Mirabolfathi, N; Moffatt, R A; Mendoza, J D Morales; Oser, S M; Page, K; Page, W A; Partridge, R; Pepin, M; Phipps, A; Prasad, K; Pyle, M; Qiu, H; Rau, W; Redl, P; Reisetter, A; Ricci, Y; Roberts, A; Saab, T; Sadoulet, B; Sander, J; Schnee, R W; Scorza, S; Serfass, B; Shank, B; Speller, D; Toback, D; Upadhyayula, S; Villano, A N; Welliver, B; Wilson, J S; Wright, D H; Yang, X; Yellin, S; Yen, J J; Young, B A; Zhang, J

    2015-01-01

    We examine the consequences of the effective field theory (EFT) of dark matter-nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.

  19. The Inner Experience of Living Matter

    DEFF Research Database (Denmark)

    Sørensen, Asger

    The dialectical aspect in the work of George Bataille is often neglected. At the suggestion of Foucault and Derrida, Bataille is most often even taken to be a non-dialectical thinker. But Bataille worked intensely with Hegel's ideas, his thought was expressed in Hegelian terms, and both his...... epistemology and his ontology can be considered a determinate negation of Hegel's position in the Phenomenology. This is shown, first, by analyzing Bataille's notions of `inner experience', and, second, by showing how Bataille extends dialectics to the natural, non-human realm, and even conceives the link...

  20. Direct Dark Matter Search with the CRESST II Experiment

    CERN Document Server

    Schieck, J; Bento, A; Bucci, C; Canonica, L; Defay, X; Erb, A; Feilitzsch, F v; Iachellini, N Ferreiro; Gorla, P; Guetlein, A; Hauff, D; Jochum, J; Kiefer, M; Kluck, H; Kraus, H; Lanfranchi, J-C; Loebell, J; Mancuso, M; Muenster, A; Pagliarone, C; Petricca, F; Potzel, W; Pröbst, F; Puig, R; Reindl, F; Schaeffner, K; Schoenert, S; Seidel, W; Stahlberg, M; Stodolsky, L; Strandhagen, C; Strauss, R; Tanzke, A; Thi, H H Trinh; Turkoglu, C; Uffinger, M; Ulrich, A; Usherov, I; Wawoczny, S; Willers, M; Wueustrich, M; Zoeller, A

    2016-01-01

    The quest for the particle nature of dark matter is one of the big open questions of modern physics. A well motivated candidate for dark matter is the so-called WIMP - a weakly interacting massive particle. Recently several theoretically well-motivated models with dark matter candidates in a mass region below the WIMP mass-scale gained also a lot of interest, theoretically and experimentally. The CRESST II experiment located at the Gran Sasso laboratory in Italy is optimised for the detection of the elastic scattering of these low-mass dark matter particles with ordinary matter. We show the results obtained with an improved detector setup with increased radio purity and enhanced background rejection and the results obtained with a dedicated low-threshold analysis of a single conventional detector module. The limit achieved is the most stringent limit achieved for direct dark matter experiments in the mass region below 1.8 GeV/$c^{2}$. We will discuss the expected performance for new small CRESST-type detector...

  1. Search for inelastic dark matter with the CDMS II experiment

    CERN Document Server

    Ahmed, Z; Arrenberg, S; Bailey, C N; Balakishiyeva, D; Baudis, L; Bauer, D A; Brink, P L; Bruch, T; Bunker, R; Cabrera, B; Caldwell, D O; Cooley, J; Silva, E do Couto e; Cushman, P; Daal, M; DeJongh, F; Di Stefano, P; Dragowsky, M R; Duong, L; Fallows, S; Figueroa-Feliciano, E; Filippini, J; Fox, J; Fritts, M; Golwala, S R; Hall, J; Hennings-Yeomans, R; Hertel, S A; Holmgren, D; Hsu, L; Huber, M E; Kamaev, O; Kiveni, M; Kos, M; Leman, S W; Liu, S; Mahapatra, R; Mandic, V; McCarthy, K A; Mirabolfathi, N; Moore, D; Nelson, H; Ogburn, R W; Phipps, A; Pyle, M; Qiu, X; Ramberg, E; Rau, W; Razeti, M; Reisetter, A; Resch, R; Saab, T; Sadoulet, B; Sander, J; Schnee, R W; Seitz, D N; Serfass, B; Sundqvist, K M; Tarka, M; Wikus, P; Yellin, S; Yoo, J; Young, B A; Zhang, J

    2010-01-01

    Results are presented from a reanalysis of the entire five-tower data set acquired with the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory, with an exposure of 969 kg-days. The analysis window was extended to a recoil energy of 150 keV, and an improved surface-event background-rejection cut was defined to increase the sensitivity of the experiment to the inelastic dark matter (IDM) model. Three dark matter candidates were found between 25 keV and 150 keV. The probability to observe three or more background events in this energy range is 11%. Due to the occurrence of these events the constraints on the IDM parameter space are slightly less stringent than those from our previous analysis, which used a narrower energy window of 10-100 keV.

  2. Challenges in QCD matter physics -The scientific programme of the Compressed Baryonic Matter experiment at FAIR

    Science.gov (United States)

    Ablyazimov, T.; Abuhoza, A.; Adak, R. P.; Adamczyk, M.; Agarwal, K.; Aggarwal, M. M.; Ahammed, Z.; Ahmad, F.; Ahmad, N.; Ahmad, S.; Akindinov, A.; Akishin, P.; Akishina, E.; Akishina, T.; Akishina, V.; Akram, A.; Al-Turany, M.; Alekseev, I.; Alexandrov, E.; Alexandrov, I.; Amar-Youcef, S.; Anđelić, M.; Andreeva, O.; Andrei, C.; Andronic, A.; Anisimov, Yu.; Appelshäuser, H.; Argintaru, D.; Atkin, E.; Avdeev, S.; Averbeck, R.; Azmi, M. D.; Baban, V.; Bach, M.; Badura, E.; Bähr, S.; Balog, T.; Balzer, M.; Bao, E.; Baranova, N.; Barczyk, T.; Bartoş, D.; Bashir, S.; Baszczyk, M.; Batenkov, O.; Baublis, V.; Baznat, M.; Becker, J.; Becker, K.-H.; Belogurov, S.; Belyakov, D.; Bendarouach, J.; Berceanu, I.; Bercuci, A.; Berdnikov, A.; Berdnikov, Y.; Berendes, R.; Berezin, G.; Bergmann, C.; Bertini, D.; Bertini, O.; Beşliu, C.; Bezshyyko, O.; Bhaduri, P. P.; Bhasin, A.; Bhati, A. K.; Bhattacharjee, B.; Bhattacharyya, A.; Bhattacharyya, T. K.; Biswas, S.; Blank, T.; Blau, D.; Blinov, V.; Blume, C.; Bocharov, Yu.; Book, J.; Breitner, T.; Brüning, U.; Brzychczyk, J.; Bubak, A.; Büsching, H.; Bus, T.; Butuzov, V.; Bychkov, A.; Byszuk, A.; Cai, Xu; Cãlin, M.; Cao, Ping; Caragheorgheopol, G.; Carević, I.; Cătănescu, V.; Chakrabarti, A.; Chattopadhyay, S.; Chaus, A.; Chen, Hongfang; Chen, LuYao; Cheng, Jianping; Chepurnov, V.; Cherif, H.; Chernogorov, A.; Ciobanu, M. I.; Claus, G.; Constantin, F.; Csanád, M.; D'Ascenzo, N.; Das, Supriya; Das, Susovan; de Cuveland, J.; Debnath, B.; Dementiev, D.; Deng, Wendi; Deng, Zhi; Deppe, H.; Deppner, I.; Derenovskaya, O.; Deveaux, C. A.; Deveaux, M.; Dey, K.; Dey, M.; Dillenseger, P.; Dobyrn, V.; Doering, D.; Dong, Sheng; Dorokhov, A.; Dreschmann, M.; Drozd, A.; Dubey, A. K.; Dubnichka, S.; Dubnichkova, Z.; Dürr, M.; Dutka, L.; Dželalija, M.; Elsha, V. V.; Emschermann, D.; Engel, H.; Eremin, V.; Eşanu, T.; Eschke, J.; Eschweiler, D.; Fan, Huanhuan; Fan, Xingming; Farooq, M.; Fateev, O.; Feng, Shengqin; Figuli, S. P. D.; Filozova, I.; Finogeev, D.; Fischer, P.; Flemming, H.; Förtsch, J.; Frankenfeld, U.; Friese, V.; Friske, E.; Fröhlich, I.; Frühauf, J.; Gajda, J.; Galatyuk, T.; Gangopadhyay, G.; García Chávez, C.; Gebelein, J.; Ghosh, P.; Ghosh, S. K.; Gläßel, S.; Goffe, M.; Golinka-Bezshyyko, L.; Golovatyuk, V.; Golovnya, S.; Golovtsov, V.; Golubeva, M.; Golubkov, D.; Gómez Ramírez, A.; Gorbunov, S.; Gorokhov, S.; Gottschalk, D.; Gryboś, P.; Grzeszczuk, A.; Guber, F.; Gudima, K.; Gumiński, M.; Gupta, A.; Gusakov, Yu.; Han, Dong; Hartmann, H.; He, Shue; Hehner, J.; Heine, N.; Herghelegiu, A.; Herrmann, N.; Heß, B.; Heuser, J. M.; Himmi, A.; Höhne, C.; Holzmann, R.; Hu, Dongdong; Huang, Guangming; Huang, Xinjie; Hutter, D.; Ierusalimov, A.; Ilgenfritz, E.-M.; Irfan, M.; Ivanischev, D.; Ivanov, M.; Ivanov, P.; Ivanov, Valery; Ivanov, Victor; Ivanov, Vladimir; Ivashkin, A.; Jaaskelainen, K.; Jahan, H.; Jain, V.; Jakovlev, V.; Janson, T.; Jiang, Di; Jipa, A.; Kadenko, I.; Kähler, P.; Kämpfer, B.; Kalinin, V.; Kallunkathariyil, J.; Kampert, K.-H.; Kaptur, E.; Karabowicz, R.; Karavichev, O.; Karavicheva, T.; Karmanov, D.; Karnaukhov, V.; Karpechev, E.; Kasiński, K.; Kasprowicz, G.; Kaur, M.; Kazantsev, A.; Kebschull, U.; Kekelidze, G.; Khan, M. M.; Khan, S. A.; Khanzadeev, A.; Khasanov, F.; Khvorostukhin, A.; Kirakosyan, V.; Kirejczyk, M.; Kiryakov, A.; Kiš, M.; Kisel, I.; Kisel, P.; Kiselev, S.; Kiss, T.; Klaus, P.; Kłeczek, R.; Klein-Bösing, Ch.; Kleipa, V.; Klochkov, V.; Kmon, P.; Koch, K.; Kochenda, L.; Koczoń, P.; Koenig, W.; Kohn, M.; Kolb, B. W.; Kolosova, A.; Komkov, B.; Korolev, M.; Korolko, I.; Kotte, R.; Kovalchuk, A.; Kowalski, S.; Koziel, M.; Kozlov, G.; Kozlov, V.; Kramarenko, V.; Kravtsov, P.; Krebs, E.; Kreidl, C.; Kres, I.; Kresan, D.; Kretschmar, G.; Krieger, M.; Kryanev, A. V.; Kryshen, E.; Kuc, M.; Kucewicz, W.; Kucher, V.; Kudin, L.; Kugler, A.; Kumar, Ajit; Kumar, Ashwini; Kumar, L.; Kunkel, J.; Kurepin, A.; Kurepin, N.; Kurilkin, A.; Kurilkin, P.; Kushpil, V.; Kuznetsov, S.; Kyva, V.; Ladygin, V.; Lara, C.; Larionov, P.; Laso García, A.; Lavrik, E.; Lazanu, I.; Lebedev, A.; Lebedev, S.; Lebedeva, E.; Lehnert, J.; Lehrbach, J.; Leifels, Y.; Lemke, F.; Li, Cheng; Li, Qiyan; Li, Xin; Li, Yuanjing; Lindenstruth, V.; Linnik, B.; Liu, Feng; Lobanov, I.; Lobanova, E.; Löchner, S.; Loizeau, P.-A.; Lone, S. A.; Lucio Martínez, J. A.; Luo, Xiaofeng; Lymanets, A.; Lyu, Pengfei; Maevskaya, A.; Mahajan, S.; Mahapatra, D. P.; Mahmoud, T.; Maj, P.; Majka, Z.; Malakhov, A.; Malankin, E.; Malkevich, D.; Malyatina, O.; Malygina, H.; Mandal, M. M.; Mandal, S.; Manko, V.; Manz, S.; Marin Garcia, A. M.; Markert, J.; Masciocchi, S.; Matulewicz, T.; Meder, L.; Merkin, M.; Mialkovski, V.; Michel, J.; Miftakhov, N.; Mik, L.; Mikhailov, K.; Mikhaylov, V.; Milanović, B.; Militsija, V.; Miskowiec, D.; Momot, I.; Morhardt, T.; Morozov, S.; Müller, W. F. J.; Müntz, C.; Mukherjee, S.; Muñoz Castillo, C. E.; Murin, Yu.; Najman, R.; Nandi, C.; Nandy, E.; Naumann, L.; Nayak, T.; Nedosekin, A.; Negi, V. S.; Niebur, W.; Nikulin, V.; Normanov, D.; Oancea, A.; Oh, Kunsu; Onishchuk, Yu.; Ososkov, G.; Otfinowski, P.; Ovcharenko, E.; Pal, S.; Panasenko, I.; Panda, N. R.; Parzhitskiy, S.; Patel, V.; Pauly, C.; Penschuck, M.; Peshekhonov, D.; Peshekhonov, V.; Petráček, V.; Petri, M.; Petriş, M.; Petrovici, A.; Petrovici, M.; Petrovskiy, A.; Petukhov, O.; Pfeifer, D.; Piasecki, K.; Pieper, J.; Pietraszko, J.; Płaneta, R.; Plotnikov, V.; Plujko, V.; Pluta, J.; Pop, A.; Pospisil, V.; Poźniak, K.; Prakash, A.; Prasad, S. K.; Prokudin, M.; Pshenichnov, I.; Pugach, M.; Pugatch, V.; Querchfeld, S.; Rabtsun, S.; Radulescu, L.; Raha, S.; Rami, F.; Raniwala, R.; Raniwala, S.; Raportirenko, A.; Rautenberg, J.; Rauza, J.; Ray, R.; Razin, S.; Reichelt, P.; Reinecke, S.; Reinefeld, A.; Reshetin, A.; Ristea, C.; Ristea, O.; Rodriguez Rodriguez, A.; Roether, F.; Romaniuk, R.; Rost, A.; Rostchin, E.; Rostovtseva, I.; Roy, Amitava; Roy, Ankhi; Rożynek, J.; Ryabov, Yu.; Sadovsky, A.; Sahoo, R.; Sahu, P. K.; Sahu, S. K.; Saini, J.; Samanta, S.; Sambyal, S. S.; Samsonov, V.; Sánchez Rosado, J.; Sander, O.; Sarangi, S.; Satława, T.; Sau, S.; Saveliev, V.; Schatral, S.; Schiaua, C.; Schintke, F.; Schmidt, C. J.; Schmidt, H. R.; Schmidt, K.; Scholten, J.; Schweda, K.; Seck, F.; Seddiki, S.; Selyuzhenkov, I.; Semennikov, A.; Senger, A.; Senger, P.; Shabanov, A.; Shabunov, A.; Shao, Ming; Sheremetiev, A. D.; Shi, Shusu; Shumeiko, N.; Shumikhin, V.; Sibiryak, I.; Sikora, B.; Simakov, A.; Simon, C.; Simons, C.; Singaraju, R. N.; Singh, A. K.; Singh, B. K.; Singh, C. P.; Singhal, V.; Singla, M.; Sitzmann, P.; Siwek-Wilczyńska, K.; Škoda, L.; Skwira-Chalot, I.; Som, I.; Song, Guofeng; Song, Jihye; Sosin, Z.; Soyk, D.; Staszel, P.; Strikhanov, M.; Strohauer, S.; Stroth, J.; Sturm, C.; Sultanov, R.; Sun, Yongjie; Svirida, D.; Svoboda, O.; Szabó, A.; Szczygieł, R.; Talukdar, R.; Tang, Zebo; Tanha, M.; Tarasiuk, J.; Tarassenkova, O.; Târzilă, M.-G.; Teklishyn, M.; Tischler, T.; Tlustý, P.; Tölyhi, T.; Toia, A.; Topil'skaya, N.; Träger, M.; Tripathy, S.; Tsakov, I.; Tsyupa, Yu.; Turowiecki, A.; Tuturas, N. G.; Uhlig, F.; Usenko, E.; Valin, I.; Varga, D.; Vassiliev, I.; Vasylyev, O.; Verbitskaya, E.; Verhoeven, W.; Veshikov, A.; Visinka, R.; Viyogi, Y. P.; Volkov, S.; Volochniuk, A.; Vorobiev, A.; Voronin, Aleksey; Voronin, Alexander; Vovchenko, V.; Vznuzdaev, M.; Wang, Dong; Wang, Xi-Wei; Wang, Yaping; Wang, Yi; Weber, M.; Wendisch, C.; Wessels, J. P.; Wiebusch, M.; Wiechula, J.; Wielanek, D.; Wieloch, A.; Wilms, A.; Winckler, N.; Winter, M.; Wiśniewski, K.; Wolf, Gy.; Won, Sanguk; Wu, Ke-Jun; Wüstenfeld, J.; Xiang, Changzhou; Xu, Nu; Yang, Junfeng; Yang, Rongxing; Yin, Zhongbao; Yoo, In-Kwon; Yuldashev, B.; Yushmanov, I.; Zabołotny, W.; Zaitsev, Yu.; Zamiatin, N. I.; Zanevsky, Yu.; Zhalov, M.; Zhang, Yifei; Zhang, Yu; Zhao, Lei; Zheng, Jiajun; Zheng, Sheng; Zhou, Daicui; Zhou, Jing; Zhu, Xianglei; Zinchenko, A.; Zipper, W.; Żoładź, M.; Zrelov, P.; Zryuev, V.; Zumbruch, P.; Zyzak, M.

    2017-03-01

    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (√{s_{NN}}= 2.7-4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials ( μ_B > 500 MeV), effects of chiral symmetry, and the equation of state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2024, in the context of the worldwide efforts to explore high-density QCD matter.

  3. A NEW EXPERIMENT SEARCHING FOR DARK MATTER AT CERN

    CERN Multimedia

    2016-01-01

    The NA64 experiment started operations at CERN’s North Area earlier this year. It uses a unique setup to hunt down a specific type of dark matter particle called the dark photon. Some theories suggest that dark matter consists of a family of new particles and forces. In addition to gravity, dark-matter particles could interact with visible matter through a new force, which has so far escaped detection. Just as the electromagnetic force is carried by the photon, this dark force is thought to be transmitted by a particle called the dark photon. It is predicted to have a subtle interaction (a “mixing”, in particle-physics jargon) with the regular photon and therefore act as a mediator between visible and dark matter. CERN’s NA64 experiment looks for signatures of this visible-dark interaction using a simple but powerful physics concept: the conservation of energy. A beam of electrons coming from the Super Proton Synchrotron accelerator, whose initial energy is very precisely known (100 G

  4. Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

    CERN Document Server

    ,

    2016-01-01

    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram ...

  5. Boosted Dark Matter at the Deep Underground Neutrino Experiment

    CERN Document Server

    Alhazmi, Haider; Mohlabeng, Gopolang; Park, Jong-Chul

    2016-01-01

    We investigate the detection prospects of a non-standard dark sector in the context of boosted dark matter. We consider a scenario where two stable particles have a large mass difference and the heavier particle accounts for most of dark matter in our current universe. The heavier candidate is assumed to have no interaction with the standard model particles at tree-level, hence evading existing constraints. Although subdominant, the lighter dark matter particles are efficiently produced via pair-annihilation of the heavier ones in the center of the Galaxy or the Sun. The large Lorentz boost enables detection of the non-minimal dark sector in large volume terrestrial experiments via exchange of a light dark photon with electrons or nuclei. Various experiments designed for neutrino physics and proton decay are examined in detail, including Super-K and Hyper-K. In this study, we focus on the sensitivity of the far detector at the Deep Underground Neutrino Experiment for boosted dark matter produced in the center...

  6. Dark matter effective field theory scattering in direct detection experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schneck, K.; Cabrera, B.; Cerdeño, D. G.; Mandic, V.; Rogers, H. E.; Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Brandt, D.; Brink, P. L.; Bunker, R.; Caldwell, D. O.; Calkins, R.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Morales Mendoza, J. D.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Roberts, A.; Saab, T.; Sadoulet, B.; Sander, J.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.

    2015-05-18

    We examine the consequences of the effective field theory (EFT) of dark matter–nucleon scattering for current and proposed direct detection experiments. Exclusion limits on EFT coupling constants computed using the optimum interval method are presented for SuperCDMS Soudan, CDMS II, and LUX, and the necessity of combining results from multiple experiments in order to determine dark matter parameters is discussed. We demonstrate that spectral differences between the standard dark matter model and a general EFT interaction can produce a bias when calculating exclusion limits and when developing signal models for likelihood and machine learning techniques. We also discuss the implications of the EFT for the next-generation (G2) direct detection experiments and point out regions of complementarity in the EFT parameter space.

  7. Integrating In Dark Matter Astrophysics at Direct Detection Experiments

    CERN Document Server

    Friedland, Alexander

    2013-01-01

    We study the capabilities of the MAJORANA DEMONSTRATOR, a neutrinoless double-beta decay experiment currently under construction at the Sanford Underground Laboratory, as a light WIMP detector. For a cross section near the current experimental bound, the MAJORANA DEMONSTRATOR should collect hundreds or even thousands of recoil events. This opens up the possibility of simultaneously determining the physical properties of the dark matter and its local velocity distribution, directly from the data. We analyze this possibility and find that allowing the dark matter velocity distribution to float considerably worsens the WIMP mass determination. This result is traced to a previously unexplored degeneracy between the WIMP mass and the velocity dispersion. We simulate spectra using both isothermal and Via Lactea II velocity distributions and comment on the possible impact of streams. We conclude that knowledge of the dark matter velocity distribution will greatly facilitate the mass and cross section determination f...

  8. Direct dark matter detection: The diurnal variation in directional experiments

    CERN Document Server

    Vergados, J D

    2011-01-01

    We present some theoretical results relevant to the direct dark matter detection experiments, paying particular attention to directional experiments, i.e. experiments in which, not only the energy but the direction of the recoiling nucleus is observed. In directional experiments the detection rate depends on the angle between the line observation and the sun's direction of motion. Since, however, the direction of observation is fixed with respect the earth, while the Earth is rotating around its axis, in a directional experiment the angle between the direction of observation and the Sun's direction of motion will change during the day. So the observed signal in such experiments will exhibit a very interesting and characteristic periodic diurnal variation.

  9. Geneva University: Dark matter Search with the CDMS experiment

    CERN Multimedia

    Université de Genève

    2011-01-01

    Geneva University Physics Department 24, quai Ernest-Ansermet CH-1211 Geneva 4 Tel: (022) 379 62 73 Fax: (022) 379 69 92   Wednesday 21 September 2011 PARTICLE PHYSICS SEMINAR at 17.00 hrs – Stückelberg Auditorium “ Dark matter Search with the CDMS experiment ” Par Dr. Sebastian Arrenberg, Université de Zürich The Cryogenic Dark Matter Search experiment (CDMS) employs a total of 30 germanium and silicon detectors at the Soudan Underground Laboratory to detect weakly interacting massive particles (WIMPs) via their scattering from the target nuclei. Previous CDMS results, released in December 2009, set the world leading limit on the spin-independent WIMP-nucleon cross section above WIMP masses of ~50 GeV/c2 assuming elastic scattering.  In a subsequent analysis we investigated the inelastic dark matter scenario which was proposed to reconcile the disagreement between the results of DAMA/LIBRA and other existing dark matter searc...

  10. Signatures of Hierarchical Clustering in Dark Matter Detection Experiments

    CERN Document Server

    Stiff, D; Frieman, Joshua A

    2001-01-01

    In the cold dark matter model of structure formation, galaxies are assembled hierarchically from mergers and the accretion of subclumps. This process is expected to leave residual substructure in the Galactic dark halo, including partially disrupted clumps and their associated tidal debris. We develop a model for such halo substructure and study its implications for dark matter (WIMP and axion) detection experiments. We combine the Press-Schechter model for the distribution of halo subclump masses with N-body simulations of the evolution and disruption of individual clumps as they orbit through the evolving Galaxy to derive the probability that the Earth is passing through a subclump or stream of a given density. Our results suggest that it is likely that the local complement of dark matter particles includes a 1-5% contribution from a single clump. The implications for dark matter detection experiments are significant, since the disrupted clump is composed of a `cold' flow of high-velocity particles. We desc...

  11. Results from the DarkSide-50 Dark Matter Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Alden [Univ. of California, Los Angeles, CA (United States)

    2016-01-01

    While there is tremendous astrophysical and cosmological evidence for dark matter, its precise nature is one of the most significant open questions in modern physics. Weakly interacting massive particles (WIMPs) are a particularly compelling class of dark matter candidates with masses of the order 100 GeV and couplings to ordinary matter at the weak scale. Direct detection experiments are aiming to observe the low energy (<100 keV) scattering of dark matter off normal matter. With the liquid noble technology leading the way in WIMP sensitivity, no conclusive signals have been observed yet. The DarkSide experiment is looking for WIMP dark matter using a liquid argon target in a dual-phase time projection chamber located deep underground at Gran Sasso National Laboratory (LNGS) in Italy. Currently filled with argon obtained from underground sources, which is greatly reduced in radioactive 39Ar, DarkSide-50 recently made the most sensitive measurement of the 39Ar activity in underground argon and used it to set the strongest WIMP dark matter limit using liquid argon to date. This work describes the full chain of analysis used to produce the recent dark matter limit, from reconstruction of raw data to evaluation of the final exclusion curve. The DarkSide- 50 apparatus is described in detail, followed by discussion of the low level reconstruction algorithms. The algorithms are then used to arrive at three broad analysis results: The electroluminescence signals in DarkSide-50 are used to perform a precision measurement of ii longitudinal electron diffusion in liquid argon. A search is performed on the underground argon data to identify the delayed coincidence signature of 85Kr decays to the 85mRb state, a crucial ingredient in the measurement of the 39Ar activity in the underground argon. Finally, a full description of the WIMP search is given, including development of cuts, efficiencies, energy scale, and exclusion

  12. Searching for light dark matter with the SLAC millicharge experiment.

    Science.gov (United States)

    Diamond, M; Schuster, P

    2013-11-27

    New sub-GeV gauge forces ("dark photons") that kinetically mix with the photon provide a promising scenario for MeV-GeV dark matter and are the subject of a program of searches at fixed-target and collider facilities around the world. In such models, dark photons produced in collisions may decay invisibly into dark-matter states, thereby evading current searches. We reexamine results of the SLAC mQ electron beam dump experiment designed to search for millicharged particles and find that it was strongly sensitive to any secondary beam of dark matter produced by electron-nucleus collisions in the target. The constraints are competitive for dark photon masses in the ~1-30 MeV range, covering part of the parameter space that can reconcile the apparent (g-2)(μ) anomaly. Simple adjustments to the original SLAC search for millicharges may extend sensitivity to cover a sizable portion of the remaining (g-2)(μ) anomaly-motivated region. The mQ sensitivity is therefore complementary to ongoing searches for visible decays of dark photons. Compared to existing direct-detection searches, mQ sensitivity to electron-dark-matter scattering cross sections is more than an order of magnitude better for a significant range of masses and couplings in simple models.

  13. New results from the LUX Dark Matter experiment

    Science.gov (United States)

    Carmona-Benitez, Carmen; LUX Collaboration

    2016-03-01

    LUX (Large Underground Xenon) is a dark matter direct detection experiment deployed at the 4850' level of the Sanford Underground Research Facility (SURF) in Lead, SD, operating a 370 kg dual-phase xenon TPC. LUX has already proved itself to be the most sensitive dark matter detector in the world. Now, we report the results of a new analysis of the data collected during LUX's first three-month run in 2013, dramatically improving our sensitivity in the low WIMP-mass range. The new analysis lowers the analysis threshold for dark matter search thanks to two new calibrations: an injected tritium β source, and a neutron generator providing tagged nuclear recoils down to 1 . 1keV . It also includes advances on the single-photon calibration, event-reconstruction algorithms and background modeling in an enlarged fiducial volume. This new analysis gives the most stringent limits on the spin-independent WIMP-nucleon cross section in the mass range above 4GeVc-2 , with a minimum of 0 . 4 zb at 33GeVc-2 WIMP mass. This talk will provide an overview of the experiment, focusing on the recent science results.

  14. First Dark Matter Results from the XENON100 Experiment

    CERN Document Server

    Aprile, E; Arneodo, F; Askin, A; Baudis, L; Behrens, A; Brown, E; Cardoso, J M R; Choi, B; Cline, D B; Fattori, S; Ferella, A D; Giboni, K -L; Hugenberg, K; Kish, A; Lam, C W; Lamblin, J; Lang, R F; Lim, K E; Lopes, J A M; Undagoitia, T Marrodán; Mei, Y; Fernandez, A J Melgarejo; Ni, K; Oberlack, U; Orrigo, S E A; Pantic, E; Plante, G; Ribeiro, A C C; Santorelli, R; Santos, J M F dos; Schumann, M; Shagin, P; Teymourian, A; Thers, D; Tziaferi, E; Wang, H; Weinheimer, C

    2010-01-01

    The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso in Italy, is designed to search for dark matter WIMPs scattering off 62 kg of liquid xenon in an ultra-low background dual-phase time projection chamber. In this letter, we present first dark matter results from the analysis of 11.17 live days of non-blind data, acquired in October and November 2009. In the selected fiducial target of 40 kg, and within the pre-defined signal region, we observe no events and hence exclude spin-independent WIMP-nucleon elastic scattering cross-sections above 3 x 10^-44 cm^2 for 50 GeV/c^2 WIMPs at 90% confidence level. Below 20 GeV/c^2, this result challenges the interpretation of the CoGeNT or DAMA signals as being due to spin-independent, elastic, light mass WIMP interactions.

  15. Physics from solar neutrinos in dark matter direct detection experiments

    CERN Document Server

    Cerdeño, David G; Jubb, Thomas; Machado, Pedro A N; Vincent, Aaron C; hm, Céline Bøe

    2016-01-01

    The next generation of dark matter direct detection experiments will be sensitive to both coherent neutrino-nucleus and neutrino-electron scattering. This will enable them to explore aspects of solar physics, perform the lowest energy measurement of the weak angle to date, and probe contributions from new theories with light mediators. In this article, we compute the projected nuclear and electron recoil rates expected in several dark matter direct detection experiments due to solar neutrinos, and use these estimates to infer errors on future measurements of the neutrino fluxes, weak mixing angle and solar observables, as well as to constrain new physics in the neutrino sector. The combined rates of solar neutrino events in second generation experiments (SuperCDMS and LZ) can yield a measurement of the pp flux to 2.5% accuracy via electron recoil, and slightly improve the boron-8 flux determination. Assuming a low-mass argon phase, projected tonne-scale experiments like DARWIN can reduce the uncertainty on bo...

  16. Final Results of the PICASSO Dark Matter Search Experiment

    CERN Document Server

    Behnke, E; Bhattacharjee, P; Dai, X; Das, M; Davour, A; Debris, F; Dhungana, N; Farine, J; Fines-Neuschild, M; Gagnebin, S; Giroux, G; Grace, E; Jackson, C M; Kamaha, A; Krauss, C B; Lafrenière, M; Laurin, M; Lawson, I; Lessard, L; Levine, I; Marlisov, D; Martin, J -P; Mitra, P; Noble, A J; Plante, A; Podviyanuk, R; Pospisil, S; Scallon, O; Seth, S; Starinski, N; Stekl, I; Wichoski, U; Zacek, V

    2016-01-01

    The PICASSO dark matter search experiment operated an array of 32 superheated droplet detectors containing 3.2 kg of C$_{4}$F$_{10}$ and collected an exposure of 231.4 kg days at SNOLAB between March 2012 and January 2014. We report on the final results of this experiment which includes for the first time the complete data set and improved analysis techniques including acoustic localization to allow fiducialization and removal of higher activity regions within the detectors. No signal consistent with dark matter was observed. We set limits for spin-dependent interactions on protons of $\\sigma_p^{SD}$ = 1.32 $\\times$ 10$^{-2}$ pb (90% C.L.) at a WIMP mass of 20 GeV/c$^{2}$. In the spin-independent sector we exclude cross sections larger than $\\sigma_p^{SI}$ = 4.86 $\\times$ 10$^{-5 }$ pb (90% C.L.) in the region around 7 GeV/c$^{2}$. The pioneering efforts of the PICASSO experiment have paved the way forward for a next generation detector incorporating much of this technology and experience into larger mass bub...

  17. 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

  18. Status and prospects of the China Dark Matter Experiment

    Science.gov (United States)

    Liu, Shukui; Yue, Qian

    2015-05-01

    The China Dark Matter Experiment (CDEX) pursues direct searches of light Weakly Interacting Massive Particles (WIMPs) at the China Jinping Underground Laboratory (CJPL), which is the deepest operating laboratory for astroparticle research in the world. Results from a prototype CDEX-0 20 g germanium detector array and CDEX-1 994 g pPCGe(p-type Point Contact Germanium) detector are reported. The new result from CDEX-1 pPCGe excludes the CoGeNT-2013 allowed region with an identical detector technique. CDEX-10 with a PCGearray of 10 kg target mass range enclosed in a liquid argon anti-Compton detector is being constructed and tested. The CDEX program evolves into the targets of "CDEX-1T Experiment". The CDEX-1T experiment will be located in CJPL-II which is under construction and will be finished by the end of 2016.

  19. LHC experiments present new results at Quark Matter 2011 Conference

    CERN Multimedia

    CERN Press Office

    2011-01-01

    The three LHC experiments that study lead ion collisions all presented their latest results today at the annual Quark Matter conference, held this year in Annecy, France. The results are based on analysis of data collected during the last two weeks of the 2010 LHC run, when the LHC switched from protons to lead-ions. All experiments report highly subtle measurements, bringing heavy-ion physics into a new era of high precision studies.   Events recorded by the ALICE experiment from the first lead ion collisions (Nov-Dec 2010). “These results from the LHC lead ion programme are already starting bring new understanding of the primordial universe,” said CERN Director General Rolf Heuer. “The subtleties they are already seeing are very impressive.” In its infancy, just microseconds after the Big Bang, the universe consisted of a plasma of quarks and gluons (QGP), the fundamental building blocks of matter. By colliding heavy ions, physicists can turn back time an...

  20. Status of the DAMIC direct dark matter search experiment

    CERN Document Server

    Aguilar-Arevalo, A; Bertou, X; Boule, D; Butner, M; Cancelo, G; Vázquez, A Castañeda; Chavarría, A E; Neto, J R T de Melo; Dixon, S; D'Olivo, J C; Estrada, J; Moroni, G Fernandez; Torres, K P Hernández; Izraelevitch, F; Kavner, A; Kilminster, B; Lawson, I; Liao, J; López, M; Molina, J; Moreno-Granados, G; Pena, J; Privitera, P; Sarkis, Y; Scarpine, V; Schwartz, T; Haro, M Sofo; Tiffenberg, J; Machado, D Torres; Trillaud, F; You, X; Zhou, J

    2015-01-01

    The DAMIC experiment uses fully depleted, high resistivity CCDs to search for dark matter particles. With an energy threshold $\\sim$50 eV$_{ee}$, and excellent energy and spatial resolutions, the DAMIC CCDs are well-suited to identify and suppress radioactive backgrounds, having an unrivaled sensitivity to WIMPs with masses $<$6 GeV/$c^2$. Early results motivated the construction of a 100 g detector, DAMIC100, currently being installed at SNOLAB. This contribution discusses the installation progress, new calibration efforts near the threshold, a preliminary result with 2014 data, and the prospects for physics results after one year of data taking.

  1. Status of the DAMIC Direct Dark Matter Search Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Arevalo, A.; et al.

    2015-09-30

    The DAMIC experiment uses fully depleted, high resistivity CCDs to search for dark matter particles. With an energy threshold $\\sim$50 eV$_{ee}$, and excellent energy and spatial resolutions, the DAMIC CCDs are well-suited to identify and suppress radioactive backgrounds, having an unrivaled sensitivity to WIMPs with masses $<$6 GeV/$c^2$. Early results motivated the construction of a 100 g detector, DAMIC100, currently being installed at SNOLAB. This contribution discusses the installation progress, new calibration efforts near the threshold, a preliminary result with 2014 data, and the prospects for physics results after one year of data taking.

  2. New Results from the Cryogenic Dark Matter Search Experiment

    CERN Document Server

    Armel, M S; Baudis, L; Bauer, D A; Bolozdynya, A I; Brink, P L; Bunker, R; Cabrera, B; Caldwell, D O; Castle, J P; Chang, C L; Clarke, R M; Crisler, M B; Cushman, P B; Davies, A K; Dixon, R; Driscoll, D D; Duong, L; Emes, J; Ferril, R; Gaitskell, R J; Golwala, S R; Haldeman, M; Hellmig, J; Hennessey, M; Holmgren, D; Huber, M E; Kamat, S; Kurylowicz, M; Lu, A; Mahapatra, R; Mandic, V; Martinis, J M; Meunier, P; Mirabolfathi, N; Nam, S W; Nelson, H; Nelson, R; Ogburn, R W; Perales, J; Perera, T A; Perillo-Isaac, M C; Rau, W; Reisetter, A; Ross, R R; Saab, T; Sadoulet, B; Sander, J; Savage, C; Schnee, R W; Seitz, D N; Shutt, T A; Smith, G; Spadafora, A L; Thompson, J P F; Tomada, A; Wang, G; Yellin, S; Young, B A

    2003-01-01

    Using improved Ge and Si detectors, better neutron shielding, and increased counting time, the Cryogenic Dark Matter Search (CDMS) experiment has obtained stricter limits on the cross section of weakly interacting massive particles (WIMPs) elastically scattering from nuclei. Increased discrimination against electromagnetic backgrounds and reduction of neutron flux confirm WIMP-candidate events previously detected by CDMS were consistent with neutrons and give limits on spin-independent WIMP interactions which are >2X lower than previous CDMS results for high WIMP mass, and which exclude new parameter space for WIMPs with mass between 8-20 GeV/c^2.

  3. Experiments on extreme states of matter towards HIF at FAIR

    Directory of Open Access Journals (Sweden)

    Sharkov Boris

    2013-11-01

    Full Text Available The Facility for Antiproton and Ion Research in Europe (FAIR will provide worldwide unique accelerator and experimental facilities allowing for a large variety of unprecedented frontier research in extreme state of matter physics and applied science. Indeed, it is the largest basic research project on the roadmap of the European Strategy Forum of Research Infrastructures (ESFRI, and it is cornerstone of the European Research Area. FAIR offers to scientists from the whole world an abundance of outstanding research opportunities, broader in scope than any other contemporary large-scale facility worldwide. More than 2500 scientists are involved in setting up and exploiting the FAIR facility. They will push the frontiers of our knowledge in plasma, nuclear, atomic, hadron and applied physics far ahead, with important implications also for other fields in science such as cosmology, astro and particle physics, and technology. It includes 14 initial experiments, which form the four scientific pillars of FAIR. The main thrust of intense heavy ion and laser beam-matter interaction research focuses on the structure and evolution of extreme state of matter on both a microscopic and on a cosmic scale.

  4. Experiments on extreme states of matter towards HIF at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Sharkov, Boris, E-mail: boris.sharkov@fair-center.eu [FAIR GmbH, Planckstrasse 1, 64291 Darmstadt (Germany); Varentsov, Dmitry [GSI Helmholtzzentrum für Schwerionenforshung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany)

    2014-01-01

    The Facility for Antiproton and Ion Research in Europe (FAIR) will provide worldwide unique accelerator and experimental facilities allowing for a large variety of unprecedented frontier research in extreme state of matter physics and applied science. Indeed, it is the largest basic research project on the roadmap of the European Strategy Forum of Research Infrastructures (ESFRI), and it is cornerstone of the European Research Area. FAIR offers to scientists from the whole world an abundance of outstanding research opportunities, broader in scope than any other contemporary large-scale facility worldwide. More than 2500 scientists are involved in setting up and exploiting the FAIR facility. They will push the frontiers of our knowledge in plasma, nuclear, atomic, hadron and applied physics far ahead, with important implications also for other fields in science such as cosmology, astro and particle physics, and technology. It includes 14 initial experiments, which form the four scientific pillars of FAIR. The main thrust of intense heavy ion and laser beam-matter interaction research focuses on the structure and evolution of extreme state of matter on both a microscopic and on a cosmic scale.

  5. The AMS-02 Experiment and the Dark Matter Search

    CERN Document Server

    Masi, Nicolo

    AMS-02 is running after great scientific goals since one year and a half: a final setting up for dark matter searches has been achieved, allowing to study the so important antiparticle to particle ratios, which will probably be the first dark matter signals ever corroborated. Even if primary cosmic rays fluxes are subjected to a lot of uncertainties sources, some statements can be done and have been written down about dark matter properties: DM should be a heavy Majorana fermion or Spin 0 or 1 boson, with a mass from about 1 TeV to 10 TeV - unveiling a new TeV-ish search age - which could be able to originate antiparticle fluxes enhancements at high energies, both for positrons and antiprotons. All the observations, direct and indirect, point to these new paradigms or can be traced back to them quite easily. These enhancements perfectly fall into the research window of AMS-02, allowing the experiment to attack each today credible theory. Also an investigation of the Sommerfeld effect-associated dark boson wil...

  6. Model-independent approach for dark matter phenomenology: Signatures in linear colliders and cosmic positron experiments

    Indian Academy of Sciences (India)

    Shigeki Matsumoto; Nobuchika Okada

    2007-11-01

    We have studied the phenomenology of dark matter at the ILC and cosmic positron experiments based on model-independent approach. We have found a strong correlation between dark matter signatures at the ILC and those in the indirect detection experiments of dark matter. Once the dark matter is discovered in the positron experiments such as the PAMELA, its nature will be investigated in detail at the ILC.

  7. Update on the MiniCLEAN Dark Matter Experiment

    CERN Document Server

    Rielage, K; Bodmer, M; Bourque, R; Buck, B; Butcher, A; Caldwell, T; Chen, Y; Coakley, K; Flores, E; Formaggio, J A; Gastler, D; Giuliani, F; Gold, M; Grace, E; Griego, J; Guerrero, N; Guiseppe, V; Henning, R; Hime, A; Jaditz, S; Kachulis, C; Kearns, E; Kelsey, J; Klein, J R; Latorre, A; Lawson, I; Linden, S; Lopez, F; McKinsey, D N; MacMullin, S; Mastbaum, A; Mei, D -M; Monroe, J; Nikkel, J A; Oertel, J; Gann, G D Orebi; Palladino, K; Perumpilly, G; Rodriguez, L; Schnee, R; Seibert, S; Walding, J; Wang, B; Wang, J; Zhang, C

    2014-01-01

    The direct search for dark matter is entering a period of increased sensitivity to the hypothetical Weakly Interacting Massive Particle (WIMP). One such technology that is being examined is a scintillation only noble liquid experiment, MiniCLEAN. MiniCLEAN utilizes over 500 kg of liquid cryogen to detect nuclear recoils from WIMP dark matter and serves as a demonstration for a future detector of order 50 to 100 tonnes. The liquid cryogen is interchangeable between argon and neon to study the A$^{2}$ dependence of the potential signal and examine backgrounds. MiniCLEAN utilizes a unique modular design with spherical geometry to maximize the light yield using cold photomultiplier tubes in a single-phase detector. Pulse shape discrimination techniques are used to separate nuclear recoil signals from electron recoil backgrounds. MiniCLEAN will be spiked with additional $^{39}$Ar to demonstrate the effective reach of the pulse shape discrimination capability. Assembly of the experiment is underway at SNOLAB and an...

  8. Exploring the mirror matter interpretation of the DAMA experiment: Has the dark matter problem been solved?

    OpenAIRE

    Foot, R.

    2004-01-01

    The self consistency between the impressive DAMA annual modulation signal and the differential energy spectrum is an important test for dark matter candidates.Mirror matter-type dark matter passes this test while other dark matter candidates, including standard (spin-independent) WIMPs and mini-electric charged particle dark matter, do not do so well.We argue that the unique properties of mirror matter-type dark matter seem to be just those required to fully explain the data, suggesting that ...

  9. Testing Light Dark Matter Coannihilation With Fixed-Target Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Izaguirre, Eder [Brookhaven Natl. Lab.; Kahn, Yonatan [Princeton U.; Krnjaic, Gordan [Fermilab; Moschella, Matthew [Princeton U.

    2017-03-20

    In this paper, we introduce a novel program of fixed-target searches for thermal-origin Dark Matter (DM), which couples inelastically to the Standard Model. Since the DM only interacts by transitioning to a heavier state, freeze-out proceeds via coannihilation and the unstable heavier state is depleted at later times. For sufficiently large mass splittings, direct detection is kinematically forbidden and indirect detection is impossible, so this scenario can only be tested with accelerators. Here we propose new searches at proton and electron beam fixed-target experiments to probe sub-GeV coannihilation, exploiting the distinctive signals of up- and down-scattering as well as decay of the excited state inside the detector volume. We focus on a representative model in which DM is a pseudo-Dirac fermion coupled to a hidden gauge field (dark photon), which kinetically mixes with the visible photon. We define theoretical targets in this framework and determine the existing bounds by reanalyzing results from previous experiments. We find that LSND, E137, and BaBar data already place strong constraints on the parameter space consistent with a thermal freeze-out origin, and that future searches at Belle II and MiniBooNE, as well as recently-proposed fixed-target experiments such as LDMX and BDX, can cover nearly all remaining gaps. We also briefly comment on the discovery potential for proposed beam dump and neutrino experiments which operate at much higher beam energies.

  10. Purification for the XENONnT dark matter experiment

    Science.gov (United States)

    Brown, Ethan; Xenon Collaboration

    2017-01-01

    The XENON1T experiment uses 3.5 tons of liquid xenon in a cryogenic detector to search for dark matter. Its upgrade, XENONnT, will similarly house 7.5 tons of liquid xenon. Operation of these large detectors requires continual purification of the xenon in an external purifier, and the need for less than part per billion level oxygen in the xenon, coupled with the large quantity of xenon to be purified, places high demands on the rate of flow through this purification system. Building on the success of the XENON10 and XENON100 experiments, XENON1T circulates gaseous xenon through heated getters at a rate of up to 100 SLPM, pushing commercial pumps to their limits moving this large quantity of gas without interruption for several years. Two upgrades are considered for XENONnT. A custom high-capacity magnetic piston pump based on the one developed for the EXO200 experiment has been scaled up to support the high demands of this much larger experiment. Additionally, a liquid phase circulation and purification system that purifies the cryogenic liquid directly is being developed, which takes advantage of the much smaller volumetric flow demands of liquid relative to gas. The implementation of both upgrades will be presented. Supported by the National Science Foundation.

  11. Unconventional Ideas for Axion and Dark Matter Experiments

    CERN Document Server

    Caspers, Fritz

    2015-01-01

    In this contribution an entirely different way compared to conventional approaches for axion, hidden photon and dark matter (DM) detection is proposed for discussion. The idea is to use living plants which are known to be very sensitive to all kind of environmental parameters, as detectors. A possible observable in such living plants could be the natural bio-photon level, a kind of metabolism related chemoluminescence. Another observable might be morphological changes or systematic leave movements. However a big problem for such kind of experiment would be the availability of a known, controllable and calibrated DM source. The objective of this small paper is primarily to trigger a debate and not so much to present a well-defined and clearly structured proposal.

  12. Reducing 68Ge Background in Dark Matter Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T.; Orrell, John L.

    2011-03-01

    Experimental searches for dark matter include experiments with sub-0.5 keV-energy threshold high purity germanium detectors. Experimental efforts, in partnership with the CoGeNT Collaboration operating at the Soudan Underground Laboratory, are focusing on energy threshold reduction via noise abatement, reduction of backgrounds from cosmic ray generated isotopes, and ubiquitous environmental radioactive sources. The most significant cosmic ray produced radionuclide is 68Ge. This paper evaluates reducing this background by freshly mining and processing germanium ore. The most probable outcome is a reduction of the background by a factor of two, and at most a factor of four. A very cost effective alternative is to obtain processed Ge as soon as possible and store it underground for 18 months.

  13. Reducing 68Ge Background in Dark Matter Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T.; Orrell, John L.

    2011-03-01

    Experimental searches for dark matter include experiments with sub-0.5 keV-energy threshold high purity germanium detectors. Experimental efforts, in partnership with the CoGeNT Collaboration operating at the Soudan Underground Laboratory, are focusing on energy threshold reduction via noise abatement, reduction of backgrounds from cosmic ray generated isotopes, and ubiquitous environmental radioactive sources. The most significant cosmic ray produced radionuclide is 68Ge. This paper evaluates reducing this background by freshly mining and processing germanium ore. The most probable outcome is a reduction of the background by a factor of two, and at most a factor of four. A very cost effective alternative is to obtain processed Ge as soon as possible and store it underground for 18 months.

  14. Observing Dark Worlds: A crowdsourcing experiment for dark matter mapping

    CERN Document Server

    Harvey, David; Noah-Vanhoucke, Joyce; Hamner, Ben; Salimans, Tim

    2013-01-01

    We present the results and conclusions from the citizen science competition `Observing Dark Worlds', where we asked participants to calculate the positions of dark matter halos from 120 catalogues of simulated weak lensing galaxy data, using computational methods. In partnership with Kaggle (http://www.kaggle.com), 357 users participated in the competition which saw 2278 downloads of the data and 3358 submissions. We found that the best algorithms improved on the benchmark code, LENSTOOL by > 30% and could measure the positions of > 3x10^14MSun halos to less than 5'' and < 10^14MSun to within 1'. In this paper, we present a brief overview of the winning algorithms with links to available code. We also discuss the implications of the experiment for future citizen science competitions.

  15. Nanostructured Soft Matter Experiment, Theory, Simulation and Perspectives

    CERN Document Server

    Zvelindovsky, Andrei V

    2007-01-01

    This book provides an interdisciplinary overview of a new and broad class of materials under the unifying name Nanostructured Soft Matter. It covers materials ranging from short amphiphilic molecules to block copolymers, proteins, colloids and their composites, microemulsions and bio-inspired systems such as vesicles. The book considers several fundamental questions, including: how self-assembly of various soft materials with internal structure at the nanoscale can be understood, controlled and in future used in the newly emerging field of soft nanotechnology. The book offers readers a view on the subject from different perspectives, combining modern experimental approaches from physical chemistry and physics with various theoretical techniques from physics, mathematics and the most advanced computer modelling. It is the first book of this sort in the field. All chapters are written by leading international experts, bringing together experience from Canada, Germany, Great Britain, Japan, the Netherlands, Russ...

  16. Simulations of ultrafast x-ray laser experiments

    Science.gov (United States)

    Fortmann-Grote, C.; Andreev, A. A.; Appel, K.; Branco, J.; Briggs, R.; Bussmann, M.; Buzmakov, A.; Garten, M.; Grund, A.; Huebl, A.; Jurek, Z.; Loh, N. D.; Nakatsutsumi, M.; Samoylova, L.; Santra, R.; Schneidmiller, E. A.; Sharma, A.; Steiniger, K.; Yakubov, S.; Yoon, C. H.; Yurkov, M. V.; Zastrau, U.; Ziaja-Motyka, B.; Mancuso, A. P.

    2017-06-01

    Simulations of experiments at modern light sources, such as optical laser laboratories, synchrotrons, and free electron lasers, become increasingly important for the successful preparation, execution, and analysis of these experiments investigating ever more complex physical systems, e.g. biomolecules, complex materials, and ultra-short lived states of matter at extreme conditions. We have implemented a platform for complete start-to-end simulations of various types of photon science experiments, tracking the radiation from the source through the beam transport optics to the sample or target under investigation, its interaction with and scattering from the sample, and registration in a photon detector. This tool allows researchers and facility operators to simulate their experiments and instruments under real life conditions, identify promising and unattainable regions of the parameter space and ultimately make better use of valuable beamtime. In this paper, we present an overview about status and future development of the simulation platform and discuss three applications: 1.) Single-particle imaging of biomolecules using x-ray free electron lasers and optimization of x-ray pulse properties, 2.) x-ray scattering diagnostics of hot dense plasmas in high power laser-matter interaction and identification of plasma instabilities, and 3.) x-ray absorption spectroscopy in warm dense matter created by high energy laser-matter interaction and pulse shape optimization for low-isentrope dynamic compression.

  17. Terrestrial effects on dark matter-electron scattering experiments

    DEFF Research Database (Denmark)

    Emken, Timon; Kouvaris, Chris; Shoemaker, Ian M.

    2017-01-01

    techniques involving detection of dark matter-electron scattering offer new sensitivity to sub-GeV dark matter. Typically however it is implicitly assumed that the dark matter is not altered as it traverses the Earth to arrive at the detector. In this paper we study in detail the effects of terrestrial...

  18. A Large Scale Double $\\beta$ and Dark Matter Experiment GENIUS

    CERN Document Server

    Hellmig, J

    1997-01-01

    The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated the large potential of double beta decay to search for new physics beyond the Standard Model. To increase by a major step the present sensitivity for double beta decay and dark matter search much bigger source strengths and much lower backgrounds are needed than used in experiments under operation at present or under construction. We present here a study of a project proposed recently, which would operate one ton of 'naked' enriched GErmanium-detectors in liquid NItrogen as shielding in an Underground Setup (GENIUS). It improves the sensitivity to neutrino masses to 0.01 eV. A ten ton version would probe neutrino masses even down to 10^-3 eV. The first version would allow to test the atmospheric neutrino problem, the second at least part of the solar neutrino problem. Both versions would allow in addition significant contributions to testing several classes of GUT models. These are especially tests of R-parity breaking supersymmetry mo...

  19. Discretising the velocity distribution for directional dark matter experiments

    CERN Document Server

    Kavanagh, Bradley J

    2015-01-01

    Dark matter (DM) direct detection experiments which are directionally-sensitive may be the only method of probing the full velocity distribution function (VDF) of the Galactic DM halo. We present an angular basis for the DM VDF which can be used to parametrise the distribution in order to mitigate astrophysical uncertainties in future directional experiments and extract information about the DM halo. This basis consists of discretising the VDF in a series of angular bins, with the VDF being only a function of the DM speed $v$ within each bin. In contrast to other methods, such as spherical harmonic expansions, the use of this basis allows us to guarantee that the resulting VDF is everywhere positive and therefore physical. We present a recipe for calculating the event rates corresponding to the discrete VDF for an arbitrary number of angular bins $N$ and investigate the discretisation error which is introduced in this way. For smooth, Standard Halo Model-like distribution functions, only $N=3$ angular bins ar...

  20. Phonon Sensor Dynamics for Cryogenic Dark Matter Search Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Yen, Jeffrey [Stanford Univ., CA (United States)

    2015-01-01

    Understanding the quasiparticle diffusion process inside sputtered aluminum (Al thin films (~ 0.1-1 μm is critical for the Cryogenic Dark Matter Search (CDMS experiment to further optimize its detectors to directly search for dark matter. An initial study with Al films was undertaken by our group ~ 20 years ago, but some important questions were not answered at the time. This thesis can be considered a continuation of that critical study. The CDMS experiment utilizes high purity silicon and germanium crystals to simultaneously measure ionization and phonons created by particle interactions. In addition to describing some of the rich physics involved in simultaneously detecting ionization and phonons with a CDMS detector, this thesis focuses on the detailed physics of the phonon sensors themselves, which are patterned onto CDMS detector surfaces. CDMS detectors use thin sputtered Al films to collect phonon energy when it propagates to the surfaces of the detector crystals. The phonon energy breaks Cooper pairs and creates quasiparticles (qps). These qps diffuse until they get trapped in an proximitized “overlap” region where lower-Tc tungsten films connect to the Al film. These tungsten films are the transition edge sensors (W-TESs CDMS uses to readout phonon signals. We performed a wide range of experiments using several sets of test devices designed and fabricated specifically for this work. The devices were used mostly to study quasiparticle (qp transport in Al films and qp transmission through Al/W interfaces. The results of this work are being used to optimize the design of detectors for SuperCDMS SNOLAB. This thesis is intended for CDMS collaborators who are interested in knowing more about the detailed fundamentals of how our phonon sensors work so they can take full advantage of their benefits. However, this work can also be read by general readers who are interested in particle detection using TES technology. This thesis contains eight chapters. The

  1. Composite dark matter and direct-search experiments

    CERN Document Server

    Wallemacq, Quentin

    2015-01-01

    We reinterpret the results of the direct searches for dark matter in terms of composite dark matter, i.e. dark matter particles that form neutral bound states, generically called dark atoms, either with ordinary particles, or with other dark matter particles. Three different scenarios are investigated: the O-helium scenario, milli- interacting dark matter and dark anti-atoms. In each of them, dark matter interacts sufficiently strongly with terrestrial matter to be stopped in it before reaching underground detectors. As they drift towards the center of the earth by gravity, these thermal dark atoms are radiatively captured by the atoms of the active medium of underground detectors, which causes the emission of photons that produce the signals through their interactions with the electrons of the medium. This provides a way of reinterpreting the results in terms of electron recoils instead of nuclear recoils. The detailed study of the interactions of O-helium with ordinary matter shows that it is not an accepta...

  2. Effects of Subject-Area Degree and Classroom Experience on New Chemistry Teachers' Subject Matter Knowledge

    Science.gov (United States)

    Nixon, Ryan S.; Campbell, Benjamin K.; Luft, Julie A.

    2016-01-01

    Science teachers need to understand the subject matter they teach. While subject matter knowledge (SMK) can improve with classroom teaching experience, it is problematic that many secondary science teachers leave the profession before garnering extensive classroom experience. Furthermore, many new science teachers are assigned to teach science…

  3. Searches for dark matter beyond mono-jets at the ATLAS experiment

    CERN Document Server

    Wang, Rui; The ATLAS collaboration

    2017-01-01

    Dark matter can be sought in complementary experiments: direct detection, indirect detection and colliders all contribute to a comprehensive set of searches for weakly interacting massive particles (WIMPs). This talk underlines the searches for Dark Matter by the ATLAS experiment in the context of this complementarity, using models that include a mediator particle between SM and DM.

  4. Direct Dark Matter Search with the XENON100 Experiment

    Science.gov (United States)

    Mei, Yuan

    Dark matter, a non-luminous, non-baryonic matter, is thought to constitute 23 % of the matter-energy components in the universe today. Except for its gravitational effects, the existence of dark matter has never been confirmed by any other means and its nature remains unknown. If a hypothetical Weakly Interacting Massive Particle (WIMP) were in thermal equilibrium in the early universe, it could have a relic abundance close to that of dark matter today, which provides a promising particle candidate of dark matter. Minimal Super-Symmetric extensions to the standard model predicts a stable particle with mass in the range 10 GeV/c2 to 1000 GeV/c2, and spin-independent cross-section with ordinary matter nucleon sigmax power of liquid xenon, as well as a 99 kg liquid xenon active veto, the electromagnetic radiation background is greatly suppressed. By utilizing the difference of (S2/S1) between electronic recoil and nuclear recoil, the expected WIMP signature, a small nuclear recoil energy deposition, could be discriminated from electronic recoil background with high efficiency. XENON100 achieved the lowest background rate (< 2.2 x 10--2 events/kg/day/keV) in the dark matter search region (< 40 keV) among all direct dark matter detectors. With 11.2 days of data, XENON100 already sets the world's best spin-independent WIMP-nucleon cross-section limit of 2.7 x 10--44 cm2 at WIMP mass 50 GeV/c 2. With 100.9 days of data, XENON100 excludes WIMP-nucleon cross-section above 7.0 x 10--45 cm2 for a WIMP mass of 50 GeV/c2 at 90% confidence level.

  5. First results from the LUX Dark Matter Experiment

    CERN Document Server

    CERN. Geneva

    2013-01-01

    Discovery of the nature of dark matter is internationally recognized as one of the greatest contemporary challenges in science, fundamental to our understanding of the Universe. The most compelling candidates for dark matter are Weakly Interacting Massive Particles (WIMPs) that arise naturally in several models of physics beyond the Standard Model. The discovery of galactic WIMPs would therefore enlighten two of the outstanding problems of modern physics - the matter composition of the Universe and the extrapolation of the Standard Model of particle physics to GUT scales. Although no definitive signal has yet been discovered, the worldwide race towards direct detection has been dramatically accelerated by the remarkable progress and evolution of liquid xenon (LXe) time projection chambers (TPCs). They have shifted the scale of target mass by orders of magnitude whilst simultaneously reducing backgrounds to unprecedented low levels, becoming the leaders of the field and offering the most promising prospects fo...

  6. Dark Matter search with the AMS-02 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Cardano, Francesco Maria [University of Perugia, Via Pascoli n. 1, Perugia (Italy)], E-mail: cardano@fisica.unipg.it

    2008-04-01

    Late astrophysical and cosmological measurements have shown how {approx}83% of matter of the Universe is dark and non-baryonic. Supersymmetric extensions of the Standard Model can provide a good candidate as main component of Dark Matter in the neutralino {chi}. In this framework, the magnetic spectrometer AMS-02 has been conceived for the precision measurement on board of the ISS of composition and energy spectrum of cosmic rays over a wide energy range, providing the potential to detect contribution to charged particle fluxes from neutralino annihilation. Due to the general faintness of expected Dark Matter contributions to cosmic ray spectra, interesting research channels are those for which the standard astrophysical background is expected to be low, like antimatter ones. Results of various MC analysis of AMS potential in the measurement of positron, antiproton and antideuteron fluxes are presented.

  7. The XENON1T Dark Matter Search Experiment

    CERN Document Server

    Aprile, Elena

    2012-01-01

    The worldwide race towards direct dark matter detection in the form of Weakly Interacting Massive Particles (WIMPs) has been dramatically accelerated by the remarkable progress and evolution of liquid xenon time projection chambers (LXeTPCs). With a realistic discovery potential, XENON100 has already reached a sensitivity of $7\\times10^{-45}\\,\

  8. Dynamic properties of interfaces in soft matter: Experiments and theory

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2011-01-01

    The dynamic properties of interfaces often play a crucial role in the macroscopic dynamics of multiphase soft condensed matter systems. These properties affect the dynamics of emulsions, of dispersions of vesicles, of biological fluids, of coatings, of free surface flows, of immiscible polymer

  9. Krypton and radon background in the PandaX-I dark matter experiment

    Science.gov (United States)

    Li, S.; Chen, X.; Cui, X.; Fu, C.; Ji, X.; Lin, Q.; Liu, J.; Liu, X.; Tan, A.; Wang, X.; Xiao, M.; Xie, P.

    2017-02-01

    We discuss an in-situ evaluation of the 85Kr, 222Rn, and 220Rn background in PandaX-I, a 120-kg liquid xenon dark matter direct detection experiment. Combining with a simulation, their contributions to the low energy electron-recoil background in the dark matter search region are obtained.

  10. Recent Results in Dark Matter Direct Detection Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, Christopher Michael [Univ. of Chicago, IL (United States)

    2012-08-01

    In this dissertation, we study the original excess of low energy events observed by the Co- GeNT collaboration and the annual modulation reported by the DAMA/LIBRA collaboration, and discuss whether these signals could both be the result of the same elastically scattering dark matter particle. We find that, without channeling but when taking into account uncertainties in the relevant quenching factors, a dark matter candidate with a mass of approximately ~7.0 GeV and a cross section with nucleons of σDM-N ~2 x 10-40 cm2 could account for both of these observations. We also compare the region of parameter space favored by DAMA/LIBRA and CoGeNT to the constraints from XENON 10, XENON 100, and CDMS (Si).

  11. XMASS experiment, dark matter search with liquid xenon detector

    Energy Technology Data Exchange (ETDEWEB)

    Minamino, Akihiro, E-mail: minamino@scphys.kyoto-u.ac.j [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan)

    2010-11-01

    The XMASS Collaboration is developing liquid xenon detector for the purpose of direct detection of dark matter in the universe. A prototype detector was developed at Kamioka Observatory to test the basic performance of single phase liquid xenon detector. With the detector, the physical properties of liquid xenon were measured, and the performance of vertex and energy reconstruction and the self-shielding power of liquid xenon for background {gamma}-rays were confirmed.

  12. Effect of gravitational focusing on annual modulation in dark-matter direct-detection experiments.

    Science.gov (United States)

    Lee, Samuel K; Lisanti, Mariangela; Peter, Annika H G; Safdi, Benjamin R

    2014-01-10

    The scattering rate in dark-matter direct-detection experiments should modulate annually due to Earth's orbit around the Sun. The rate is typically thought to be extremized around June 1, when the relative velocity of Earth with respect to the dark-matter wind is maximal. We point out that gravitational focusing can alter this modulation phase. Unbound dark-matter particles are focused by the Sun's gravitational potential, affecting their phase-space density in the lab frame. Gravitational focusing can result in a significant overall shift in the annual-modulation phase, which is most relevant for dark matter with low scattering speeds. The induced phase shift for light O(10)  GeV dark matter may also be significant, depending on the threshold energy of the experiment.

  13. Direct detection prospects of dark vectors with xenon-based dark matter experiments

    CERN Document Server

    An, Haipeng; Pospelov, Maxim; Pradler, Josef; Ritz, Adam

    2015-01-01

    Dark matter experiments primarily search for the scattering of WIMPs on target nuclei of well shielded underground detectors. The results from liquid scintillator experiments furthermore provide precise probes of very light and very weakly coupled particles that may be absorbed by electrons. In these proceedings we summarize previously obtained constraints on long-lived dark matter vector particles $V$ (dark photons) in the $0.01-100$ keV mass range. In addition, we provide a first projected sensitivity reach for the upcoming XENON1T dark matter search to detect dark photons.

  14. Dynamical response of dark matter to galaxy evolution affects direct-detection experiments

    Science.gov (United States)

    Petersen, Michael S.; Katz, Neal; Weinberg, Martin D.

    2016-12-01

    Over a handful of rotation periods, dynamical processes in barred galaxies induce nonaxisymmetric structure in dark matter halos. Using n -body simulations of a Milky Way-like barred galaxy, we identify both a trapped dark matter component, a shadow bar, and a strong response wake in the dark matter distribution that affects the predicted dark matter detection rates for current experiments. The presence of a baryonic disk, together with well-known dynamical processes (e.g. spiral structure and bar instabilities), increases the dark matter density in the disk plane. We find that the magnitude of the combined stellar and shadow bar evolution, when isolated from the effect of the axisymmetric gravitational potential of the disk, accounts for >30 % of this overall increase in disk-plane density. This is significantly larger than that of previously claimed deviations from the standard halo model. The dark matter density and kinematic wakes driven by the Milky Way bar increase the detectability of dark matter overall, especially for the experiments with higher vmin . These astrophysical features increase the detection rate by more than a factor of 2 when compared to the standard halo model and by a factor of 10 for experiments with high minimum recoil energy thresholds. These same features increase (decrease) the annual modulation for low (high) minimum recoil energy experiments. We present physical arguments for why these dynamics are generic for barred galaxies such as the Milky Way rather than contingent on a specific galaxy model.

  15. Tritium calibration of the LUX dark matter experiment

    Science.gov (United States)

    Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bradley, A.; Bramante, R.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; de Viveiros, L.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Manalaysay, A. G.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Ott, R. A.; Palladino, K. J.; Pangilinan, M.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Young, S. K.; Zhang, C.; LUX Collaboration

    2016-04-01

    We present measurements of the electron-recoil (ER) response of the LUX dark matter detector based upon 170 000 highly pure and spatially uniform tritium decays. We reconstruct the tritium energy spectrum using the combined energy model and find good agreement with expectations. We report the average charge and light yields of ER events in liquid xenon at 180 and 105 V /cm and compare the results to the NEST model. We also measure the mean charge recombination fraction and its fluctuations, and we investigate the location and width of the LUX ER band. These results provide input to a reanalysis of the LUX run 3 weakly interacting massive particle search.

  16. Exploring SUSY light Higgs boson scenarios via dark matter experiments

    CERN Document Server

    Das, Debottam; Mambrini, Yann

    2010-01-01

    We examine the dark matter phenomenology in supersymmetric light higgs boson scenarios, adapting nonuniversal Higgs masses at the gauge coupling unification scale. The correct relic density is obtained mostly through the annihilation into a pseudoscalar $A$, which gives high values for the self-annihilation cross-section at present times. Our analysis shows that most part of the $A$ pole region can produce detectable gamma-rays and antiproton signals, and still be compatible with with recent direct detection data from XENON100 and CDMS-II.

  17. Transport of laser accelerated proton beams and isochoric heating of matter

    Energy Technology Data Exchange (ETDEWEB)

    Roth, M; Alber, I; Guenther, M; Harres, K [Inst. fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Bagnoud, V [GSI Helmholtzzentrum f. Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Brown, C; Gregori, G [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Clarke, R; Heathcote, R; Li, B [STFC, Rutherford Appleton Laboratory, Chilton, Didcot, OX14 OQX (United Kingdom); Daido, H [Photo Medical Research Center, JAEA, Kizugawa-City, Kyoto 619-0215 (Japan); Fernandez, J; Flippo, K; Gaillard, S; Gauthier, C [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Glenzer, S; Kritcher, A; Kugland, N; LePape, S [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Makita, M, E-mail: markus.roth@physik.tu-darmstadt.d [School of Mathematics and Physics, Queen' s University of Belfast, Belfast BT7 1NN (United Kingdom)

    2010-08-01

    The acceleration of intense proton and ion beams by ultra-intense lasers has matured to a point where applications in basic research and technology are being developed. Crucial for harvesting the unmatched beam parameters driven by the relativistic electron sheath is the precise control of the beam. We report on recent experiments using the PHELIX laser at GSI, the VULCAN laser at RAL and the TRIDENT laser at LANL to control and use laser accelerated proton beams for applications in high energy density research. We demonstrate efficient collimation of the proton beam using high field pulsed solenoid magnets, a prerequisite to capture and transport the beam for applications. Furthermore we report on two campaigns to use intense, short proton bunches to isochorically heat solid targets up to the warm dense matter state. The temporal profile of the proton beam allows for rapid heating of the target, much faster than the hydrodynamic response time thereby creating a strongly coupled plasma at solid density. The target parameters are then probed by X-ray Thomson scattering (XRTS) to reveal the density and temperature of the heated volume. This combination of two powerful techniques developed during the past few years allows for the generation and investigation of macroscopic samples of matter in states present in giant planets or the interior of the earth.

  18. The Scientific Reach of Multi-Ton Scale Dark Matter Direct Detection Experiments

    CERN Document Server

    Newstead, Jayden L; Krauss, Lawrence M; Dent, James B; Ferrer, Francesc

    2013-01-01

    The next generation of large scale WIMP direct detection experiments have the potential to go beyond the discovery phase and reveal detailed information about both the particle physics and astrophysics of dark matter. We report here on early results arising from the development of a detailed numerical code modeling the proposed DARWIN detector, involving both liquid argon and xenon targets. We incorporate realistic detector physics, particle physics and astrophysical uncertainties and demonstrate to what extent two targets with similar sensitivities can remove various degeneracies and allow a determination of dark matter cross sections and masses while also probing rough aspects of the dark matter phase space distribution. We find that, even assuming dominance of spin-independent scattering, multi-ton scale experiments still have degeneracies that depend sensitively on the dark matter mass, and on the possibility of isospin violation and inelasticity in interactions. We find that these experiments are best ab...

  19. Searches for Dark Matter with the ATLAS experiment

    CERN Document Server

    Lundberg, Olof; The ATLAS collaboration

    2015-01-01

    ATLAS is a multi-purpose detector aimed at fully exploiting the discovery potential of the proton-proton collisions at a center of mass energy of 8-14 TeV provided by CERN Large Hadron Collider. It is able to precisely identify and measure the properties of electrons, muons, photons, taus and hadronic jets. Thanks to an excellent hermeticity it is able to infer the production of neutrinos and dark matter particles from conservation of momentum using the missing energy observable. This talk will focus on the results of several dedicated searches for WIMP Dark Matter using the ATLAS detector. Among these searches are the so called "Mono-X" searches looking for signatures with large missing momentum recoiling against a gauge boson. We also present searches for decays of the Higgs boson into invisible states and searches for final states with missing transverse energy and third generation quarks. The results are interpreted in terms of Effective Field Theories as well as Simplified Models, and limits on nucleon-W...

  20. Tritium calibration of the LUX dark matter experiment

    CERN Document Server

    Akerib, D S; Bai, X; Bailey, A J; Balajthy, J; Beltrame, P; Bernard, E P; Bernstein, A; Biesiadzinski, T P; Boulton, E M; Bradley, A; Bramante, R; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chapman, J J; Chiller, A A; Chiller, C; Currie, A; Cutter, J E; Davison, T J R; de Viveiros, L; Dobi, A; Dobson, J E Y; Druszkiewicz, E; Edwards, B N; Faham, C H; Fiorucci, S; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C R; Hanhardt, M; Haselschwardt, S J; Hertel, S A; Hogan, D P; Horn, M; Huang, D Q; Ignarra, C M; Ihm, M; Jacobsen, R G; Ji, W; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, N A; Lee, C; Lenardo, B G; Lesko, K T; Lindote, A; Lopes, M I; Malling, D C; Manalaysay, A G; Mannino, R L; Marzioni, M F; McKinsey, D N; Mei, D M; Mock, J; Moongweluwan, M; Morad, J A; Murphy, A St J; Nehrkorn, C; Nelson, H N; Neves, F; O`Sullivan, K; Oliver-Mallory, K C; Ott, R A; Palladino, K J; Pangilinan, M; Pease, E K; Phelps, P; Reichhart, L; Rhyne, C; Shaw, S; Shutt, T A; Silva, C; Solovov, V N; Sorensen, P; Stephenson, S; Sumner, T J; Szydagis, M; Taylor, D J; Taylor, W; Tennyson, B P; Terman, P A; Tiedt, D R; To, W H; Tripathi, M; Tvrznikova, L; Uvarov, S; Verbus, J R; Webb, R C; White, J T; Whitis, T J; Witherell, M S; Wolfs, F L H; Young, S K; Zhang, C

    2015-01-01

    We present measurements of the electron-recoil (ER) response of the LUX dark matter detector based upon 170,000 highly pure and spatially-uniform tritium decays. We reconstruct the tritium energy spectrum using the combined energy model and find good agreement with expectations. We report the average charge and light yields of ER events in liquid xenon at 180 V/cm and 105 V/cm and compare the results to the NEST model. We also measure the mean charge recombination fraction and its fluctuations, and we investigate the location and width of the LUX ER band. These results provide input to a re-analysis of the LUX Run3 WIMP search.

  1. Patient experiences of inpatient hospital care: a department matter and a hospital matter.

    NARCIS (Netherlands)

    Krol, M.W.; Boer, D. de; Sixma, H.; Hoek, L. van der; Rademakers, J.J.D.J.M.; Delnoij, D.M.

    2015-01-01

    Objective: To examine the added value of measuring and possibly presenting patient experiences at the department level, in addition to the hospital level, and to explore the possibility that patient experiences differ according to the ‘type’ of hospital department. Design: Secondary analysis of data

  2. Deployment and post-deployment experiences in OEF/OIF veterans: relationship to gray matter volume.

    Directory of Open Access Journals (Sweden)

    Robin L Aupperle

    Full Text Available BACKGROUND: Combat-related PTSD has been associated with reduced gray matter volume in regions of the prefrontal and temporal cortex, hippocampus, insula, and amygdala. However, the relationship between gray matter volume and specific deployment and post-deployment experiences has not been investigated. The aim of this study was to delineate how such experiences may contribute to structural brain changes for combat veterans. METHODS: Operation Iraqi Freedom/Operation Enduring Freedom veterans (N = 32 completed magnetic resonance imaging, the Deployment Risk and Resilience Inventory, Alcohol Use Disorders Identification Test, and Clinical Administered PTSD Scale. Voxel-wise Huber robust multiple regressions were used to quantify the relationship between gray matter volume and deployment experiences (combat experiences, military social support and post-deployment symptoms (PTSD, alcohol use. RESULTS: There was an interaction between severity of combat experiences and military social support for orbitofrontal gyrus gray matter volume. Specifically, individuals with more orbitofrontal gyrus gray matter volume reported less combat experiences and higher unit support. Individuals with more severe PTSD symptoms showed reduced gray matter volume within a large temporal region (inferior temporal and parahippocampal gyrus. CONCLUSIONS: The identified association between unit support and orbitofrontal gyrus volume supports two potential resilience mechanisms to be delineated with future longitudinal studies. First, individuals with larger orbitofrontal gyrus may engage in greater quality of social interactions and thus experience combat as less stressful. Second, individuals who experience greater unit support may preserve a larger orbitofrontal gyrus, serving to "protect" them from aversive consequences of combat.

  3. Background studies for the EDELWEISS dark matter experiment

    CERN Document Server

    Armengaud, E; Beno\\^\\it, A; Bergé, L; Bergmann, T; Blümer, J; Broniatowski, A; Brudanin, V; Censier, B; Chapellier, M; Charlieux, F; Couedo, F; Coulter, P; Cox, G A; De Jesus, M; Domange, J; Drilien, A -A; Dumoulin, L; Eitel, K; Filosofov, D; Fourches, N; Gascon, J; Gerbier, G; Gros, M; Henry, S; Hervé, S; Heuermann, G; Holtzer, N; Juillard, A; Kleifges, M; Kluck, H; Kozlov, V; Kraus, H; Kudryavtsev, V A; Sueur, H Le; Loaiza, P; Marnieros, S; Menshikov, A; Navick, X-F; Nones, C; Olivieri, E; Pari, P; Paul, B; Rigaut, O; Robinson, M; Rozov, S; Sanglard, V; Schmidt, B; Scorza, S; Siebenborn, B; Semikh, S; Tcherniakhovski, D; Torrento-Coello, A S; Vagneron, L; Walker, R J; Weber, M; Yakushev, E; Zhang, X

    2013-01-01

    The EDELWEISS-II collaboration has completed a direct search for WIMP dark matter using cryogenic Ge detectors (400 g each) and 384 kg$\\times$days of effective exposure. A cross-section of $4.4 \\times 10^{-8}$ pb is excluded at 90% C.L. for a WIMP mass of 85 GeV. The next phase, EDELWEISS-III, aims to probe spin-independent WIMP-nucleon cross-sections down to a few $\\times10^{-9}$ pb. We present here the study of gamma and neutron background coming from radioactive decays in the set-up and shielding materials. We have carried out Monte Carlo simulations for the completed EDELWEISS-II setup with GEANT4 and normalised the expected background rates to the measured radioactivity levels (or their upper limits) of all materials and components. The expected gamma-ray event rate in EDELWEISS-II at 20-200 keV agrees with the observed rate of 82 events/kg/day within the uncertainties in the measured concentrations. The calculated neutron rate from radioactivity of 1.0-3.1 events (90% C.L.) at 20-200 keV in the EDELWEIS...

  4. Do Qualification, Experience and Age Matter for Principals Leadership Styles?

    Directory of Open Access Journals (Sweden)

    Muhammad Javed Sawati

    2013-07-01

    Full Text Available The main focus of present study was to find out the prevalent leadership styles of principals in government schools of Khyber Pakhtunkhwa and to find relationship of leadership styles with qualifications, age and experience of the principals. On the basis of analyzed data, four major leadership styles of the principals were identified as Eclectic, Democratic, Autocratic, and Free-rein. However, a small proportion of the principal had no dominant leadership style. This study shows that principals’ leadership styles have no significant correlation with age, experience and qualification.

  5. Perrault's experiments, a matter of soil hydrology and epistemology

    Science.gov (United States)

    Barontini, Stefano; Berta, Andrea; Settura, Matteo

    2017-04-01

    The studies conducted in the second half of the Sixteenth Century were crucial both for the hydrological knowledge and for the modern epistemology. In fact thanks to the new experiment-based scientific approach the Sun was about to be fully recognized as the engine of the hydrological cycle instead of an endogenous engine placed in the depths of the Earth, and the original Aristotelic approach to the description of the nature, based on the the four qualities (hot and cold, dry and moist), was got over. At the same time, the questions posed on the hydrological cycle and on the soil hydrology, which are hardly reproducible by means of a controlled laboratory model, severely tested the modern scientific approach at its beginning, and contributed to the development of modern epistemology. Perrault's classical book De l'origine des fontaines (On the origin of springs, 1674) is deeply rooted in these debates. In this book he performed experiments and collected many observations both to assess the water balance at the basin scale and to understand the water movement in the upper soil layers. Particularly he performed four experiments to understand whether the water could spontaneously rise within the soil from the water table and originate springs (1st and 2nd experiment), how deep the rainfall could percolate through the soil and recharge the groundwater table (3rd one), and whether salty water remained salty when rising into the soil by capillary action (4th one). In order to do so he filled with different soils a leaden pipe, 65cm long, and observed their performances against capillary rise, infiltration, percolation and water-content redistribution. The great detail of the experimental report allowed us to quantitatively re-experience the first three ones in the laboratory, with comparable results to Perrault's ones. Moreover it allowed us to recognize both the omitted data which would be needed for a complete repeatability, and the observations which leaded Perrault

  6. Radon backgrounds in the DRIFT-II directional dark matter experiments

    CERN Document Server

    Daw, E; Gauvreau, J -L; Gold, M; Harmon, L J; Landers, J M; Lee, E R; Loomba, D; Miller, E H; Murphy, A StJ; Paling, S M; Pipe, M; Robinson, M; Sadler, S; Scarff, A; Snowden-Ifft, D P; Spooner, N J C; Walker, D

    2013-01-01

    Low pressure gas Time Projection Chambers being developed for directional Dark Matter searches offer a technology with high particle identification power, combined with poten- tial to produce a definitive detection of galactic Weakly Interacting Massive Particle (WIMP) Dark Matter. A source of background events in such experiments, able to mimic genuine WIMP in- duced nuclear recoil tracks, arises from potential radon contamination and the recoils that result from associated daughter nuclei, termed Radon Progeny Recoils (RPRs). We present here experi- mental data from a long-term study of this background using the DRIFT-II directional dark matter experiment at the Boulby Underground Laboratory. By detailed examination of event classes in both spatial and time coordinates using 5.5 years of data we show ability to determine the origin of 4 specific background populations and describe development of new technology and mitigation strategies to suppress them.

  7. Dark matter searches with the CDMS II experiment

    Energy Technology Data Exchange (ETDEWEB)

    Saab, T. [Department of Physics, University of Florida, Gainesville, FL 32611 (United States); Collaboration: CDMS Collaboration

    2014-06-24

    The CDMS II experiment ran between 2003 and 2009. A total of 30 germanium and silicon ZIP detectors were operated, producing a high quality set of data that has been analyzed for evidence of and placed leading constraints on standard, low-mass, electron-recoil, and annually modulating WIMP interactions. This article will describe the general operation principles behind the CDMS detectors, report on the results of major Ge and Si detector analyses, and describe the current and future activities of the SuperCDMS program.

  8. Physics reach of the XENON1T dark matter experiment

    CERN Document Server

    Aprile, E; Agostini, F; Alfonsi, M; Amaro, F D; Anthony, M; Arazi, L; Arneodo, F; Balan, C; Barrow, P; Baudis, L; Bauermeister, B; Berger, T; Breur, P; Breskin, A; Brown, A; Brown, E; Bruenner, S; Bruno, G; Budnik, R; Bütikofer, L; Cardoso, J M R; Cervantes, M; Cichon, D; Coderre, D; Colijn, A P; Conrad, J; Contreras, H; Cussonneau, J P; Decowski, M P; de Perio, P; Di Gangi, P; Di Giovanni, A; Duchovni, E; Fattori, S; Ferella, A D; Fieguth, A; Franco, D; Fulgione, W; Galloway, M; Garbini, M; Geis, C; Goetzke, L W; Greene, Z; Grignon, C; Gross, E; Hampel, W; Hasterok, C; Itay, R; Kaether, F; Kaminsky, B; Kessler, G; Kish, A; Landsman, H; Lang, R F; Lellouch, D; Levinson, L; Calloch, M Le; Levy, C; Lindemann, S; Lindner, M; Lopes, J A M; Lyashenko, A; Macmullin, S; Manfredini, A; Undagoitia, T Marrodán; Masbou, J; Massoli, F V; Mayani, D; Fernandez, A J Melgarejo; Meng, Y; Messina, M; Micheneau, K; Miguez, B; Molinario, A; Murra, M; Naganoma, J; Oberlack, U; Orrigo, S E A; Pakarha, P; Pelssers, B; Persiani, R; Piastra, F; Pienaar, J; Plante, G; Priel, N; Rauch, L; Reichard, S; Reuter, C; Rizzo, A; Rosendahl, S; Rupp, N; Santos, J M F dos; Sartorelli, G; Scheibelhut, M; Schindler, S; Schreiner, J; Schumann, M; Lavina, L Scotto; Selvi, M; Shagin, P; Simgen, H; Stein, A; Thers, D; Tiseni, A; Trinchero, G; Tunnell, C; von Sivers, M; Wall, R; Wang, H; Weber, M; Wei, Y; Weinheimer, C; Wulf, J; Zhang, Y

    2015-01-01

    The XENON1T experiment is currently in the commissioning phase at the Laboratori Nazionali del Gran Sasso, Italy. In this article we study the experiment's expected sensitivity to the spin-independent WIMP-nucleon interaction cross section, based on Monte Carlo predictions of the electronic and nuclear recoil backgrounds. The total electronic recoil background in $1$ tonne fiducial volume and ($1$, $12$) keV electronic recoil equivalent energy region, before applying any selection to discriminate between electronic and nuclear recoils, is $(1.80 \\pm 0.15) \\cdot 10^{-4}$ ($\\rm{kg} \\cdot day \\cdot keV)^{-1}$, mainly due to the decay of $^{222}\\rm{Rn}$ daughters inside the xenon target. The nuclear recoil background in the corresponding nuclear recoil equivalent energy region ($4$, $50$) keV, is composed of $(0.6 \\pm 0.1)$ ($\\rm{t} \\cdot y)^{-1}$ from radiogenic neutrons, $(1.8 \\pm 0.3) \\cdot 10^{-2}$ ($\\rm{t} \\cdot y)^{-1}$ from coherent scattering of neutrinos, and less than $0.01$ ($\\rm{t} \\cdot y)^{-1}$ from...

  9. The Dynamical Response of Dark Matter to Galaxy Evolution Affects Direct-Detection Experiments

    CERN Document Server

    Petersen, Michael S; Weinberg, Martin D

    2016-01-01

    Over a handful of rotation periods, dynamical processes in barred galaxies induce non-axisymmetric structure in dark matter halos. Using n-body simulations of a Milky Way-like barred galaxy, we identify both a trapped dark-matter component, a shadow bar, and a strong response wake in the dark-matter distribution that affects the predicted dark-matter detection rates for current experiments. The presence of a baryonic disk together with well-known dynamical processes (e.g. spiral structure and bar instabilities) increase the dark matter density in the disk plane. We find that the magnitude of the combined stellar and shadow bar evolution, when isolated from the effect of the axisymmetric gravitational potential of the disk, accounts for >30% of this overall increase in disk-plane density. This is significantly larger that of previously claimed deviations from the standard halo model. The dark-matter density and kinematic wakes driven by the Milky Way bar increase the detectability of dark matter overall, espec...

  10. Undergraduate Laboratory Experiment: Measuring Matter Antimatter Asymmetries at the Large Hadron Collider

    CERN Document Server

    Parkes, Chris; Gutierrez, J

    2015-01-01

    This document is the student manual for a third year undergraduate laboratory experiment at the University of Manchester. This project aims to measure a fundamental difference between the behaviour of matter and antimatter through the analysis of data collected by the LHCb experiment at the Large Hadron Collider. The three-body dmecays $B^\\pm \\rightarrow h^\\pm h^+ h^-$, where $h^\\pm$ is a $\\pi^\\pm$ or $K^\\pm$ are studied. The inclusive matter antimatter asymmetry is calculated, and larger asymmetries are searched for in localized regions of the phase-space.

  11. Can Tonne-Scale Direct Detection Experiments Discover Nuclear Dark Matter?

    CERN Document Server

    Butcher, A; Monroe, J; West, S M

    2016-01-01

    Models of nuclear dark matter propose that the dark sector contains large composite states consisting of dark nucleons in analogy to Standard Model nuclei. We examine the direct detection phenomenology of a particular class of nuclear dark matter model at the current generation of tonne-scale liquid noble experiments, in particular DEAP-3600 and XENON1T. In our chosen nuclear dark matter scenario distinctive features arise in the recoil energy spectra due to the non-point-like nature of the composite dark matter state. We calculate the number of events required to distinguish these spectra from those of a standard point-like WIMP state with a decaying exponential recoil spectrum. In the most favourable regions of nuclear dark matter parameter space, we find that a few tens of events are needed to distinguish nuclear dark matter from WIMPs at the $3\\,\\sigma$ level in a single experiment. Given the total exposure time of DEAP-3600 and XENON1T we find that at best a $2\\,\\sigma$ distinction is possible by these e...

  12. Leptophilic Dark Matter in Direct Detection Experiments and in the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, Joachim; Niro, Viviana; Schwetz, Thomas; Zupan, Jure

    2010-11-01

    Dark matter interacting predominantly with leptons instead of nuclear matter has received a lot of interest recently. In this talk, we investigate the signals expected from such 'leptophilic Dark Matter' in direct detection experiments and in experiments looking for Dark Matter annihilation into neutrinos in the Sun. In a model-independent framework, we calculate the expected interaction rates for different scattering processes, including elastic and inelastic scattering off atomic electron shells, as well as loop-induced scattering off atomic nuclei. In those cases where the last effect dominates, leptophilic Dark Matter cannot be distinguished from conventional WIMPs. On the other hand, if inelastic scattering off the electron shell dominates, the expected event spectrum in direct detection experiments is different and would provide a distinct signal. However, we find that the signals in DAMA and/or CoGeNT cannot be explained by invoking leptophilic DM because the predicted and observed energy spectra do not match, and because of neutrino bounds from the Sun.

  13. Phases of Strongly Interacting Matter in the Brahms Experiment

    Science.gov (United States)

    Staszel, P.

    2007-11-01

    We review results obtained by the BRAHMS experiment at the Relativistic Heavy Ion Collider (RHIC) for the systems of Au + Au and Cu + Cu colliding at √ {sNN} = 200 GeV and at 62.4 GeV, and p + p colliding at √ {sNN} = 200 GeV. The observed number of charged particles produced per unit of rapidity in the central rapidity region indicates that a high energy density system is produced at the initial stage of the Au + Au reaction. Analysis of anti-particle to particle ratios as a function of rapidity and collision energy reveal that particle populations at the chemical freeze-out stage for heavy-ion reactions at and above SPS energies are controlled by the baryon chemical potential. We present rapidity dependent bar {p}/π - ratios within 0 < y < 3 for Au + Au and Cu + Cu at √ {sNN} = 200 GeV. The ratios are enhanced in nucleus-nucleus collisions as compared to p + p collisions. The particle ratios are discussed in terms of their system size and rapidity dependence. From comparison of RAA for different systems and energies it is found that RAA increases with decreasing collision energy, decreasing system size, and when going towards more peripheral collisions. However, RAA shows only a very weak dependence on rapidity (for 0 < y < 3.2), both for pions and protons.

  14. Interplay and Characterization of Dark Matter Searches at Colliders and in Direct Detection Experiments

    CERN Document Server

    Malik, Sarah A.; Araujo, Henrique; Belyaev, A.; Bœhm, Céline; Brooke, Jim; Buchmueller, Oliver; Davies, Gavin; De Roeck, Albert; de Vries, Kees; Dolan, Matthew J.; Ellis, John; Fairbairn, Malcolm; Flaecher, Henning; Gouskos, Loukas; Khoze, Valentin V.; Landsberg, Greg; Newbold, Dave; Papucci, Michele; Sumner, Timothy; Thomas, Marc; Worm, Steven

    2015-01-01

    In this White Paper we present and discuss a concrete proposal for the consistent interpretation of Dark Matter searches at colliders and in direct detection experiments. Based on a specific implementation of simplified models of vector and axial-vector mediator exchanges, this proposal demonstrates how the two search strategies can be compared on an equal footing.

  15. Students' Experiences and Perceptions of In-Depth Approaches in Teaching and Understanding Subject Matter

    Science.gov (United States)

    Doumas, Kyriaki

    2012-01-01

    Students' experiences and perceptions of good teaching and understanding in literature and physics during one school year were investigated through in-depth interviews with students in eight Greek high school classes in the first, second and third grade. The pedagogical quality of in-depth teaching and understanding of subject matter, as described…

  16. CP violation and matter effect for a variable earth density in very long baseline experiments

    Energy Technology Data Exchange (ETDEWEB)

    Brahmachari, Biswajoy; Choubey, Sandhya E-mail: sandhya@he.sissa.it; Roy, Probir

    2003-11-03

    The perturbative treatment of subdominant oscillation and matter effect in neutrino beams/superbeams, propagating over long baselines and being used to look for CP violation, is studied here for a general matter density function varying with distance. New lowest order analytic expressions are given for different flavour transition and survival probabilities in a general neutrino mixing basis and a variable earth matter density profile. It is demonstrated that the matter effect in the muon neutrino (antineutrino) flavour survival probability vanishes to this order, provided the depletion, observed for atmospheric muon neutrinos and antineutrinos at super-Kamiokande, is strictly maximal. This result is independent of the earth density profile and the distance L between the source and the detector. In the general variable density case we show that one cannot separate the matter induced asymmetry from a genuine CP effect by keeping two detectors at distances L{sub 1} and L{sub 2} from the source while maintaining a fixed ratio L{sub 1}/E{sub 1}=L{sub 2}/E{sub 2}. This needs to be done numerically and we estimate the asymmetry generated by the earth matter effect with particular density profiles and some chosen parameters for very long baseline neutrino oscillation experiments.

  17. Experience-dependent plasticity in white matter microstructure: Reasoning training alters structural connectivity

    Directory of Open Access Journals (Sweden)

    Allyson P Mackey

    2012-08-01

    Full Text Available Diffusion tensor imaging (DTI techniques have made it possible to investigate white matter plasticity in humans. Changes in DTI measures, principally increases in fractional anisotropy (FA, have been observed following training programs as diverse as juggling, meditation, and working memory. Here, we sought to test whether three months of reasoning training could alter white matter microstructure. We recruited participants (n=23 who were enrolled in a course to prepare for the Law School Admission Test (LSAT, a test that places strong demands on reasoning skills, as well as age- and IQ-matched controls planning to take the LSAT in the future (n=22. DTI data were collected at two scan sessions scheduled three months apart. In trained participants but not controls, we observed decreases in radial diffusivity (RD in white matter connecting frontal cortices, and in mean diffusivity (MD within frontal and parietal lobe white matter. Further, participants exhibiting larger gains on the LSAT exhibited greater decreases in MD in the right internal capsule. In summary, reasoning training altered multiple measures of white matter structure in young adults. While the cellular underpinnings are unknown, these results provide evidence of experience-dependent white matter changes that may not be limited to myelination.

  18. Testing keV sterile neutrino dark matter in future direct detection experiments

    CERN Document Server

    Campos, Miguel D

    2016-01-01

    We determine constraints on sterile neutrino warm dark matter through direct detection experiments, taking XENON100 and its future stages as example. If keV-scale sterile neutrinos scatter inelastically with bound electrons of the target material, an electron recoil signal is generated. This can be used to set limits on the sterile neutrino mass and its mixing with the active sector. While not competitive with astrophysical constraints from X-ray data, the constraints are the first direct laboratory bounds on sterile neutrino warm dark matter, and will be in some parts of parameter space the strongest limits on keV-scale neutrinos.

  19. Evaluation of (alpha,n) Induced Neutrons as a Background for Dark Matter Experiments

    CERN Document Server

    Mei, D -M; Hime, A

    2008-01-01

    Neutrons from ($\\alpha$,n) reaction through thorium and uranium decays are important sources of background for direct dark matter detection. Neutron yield and energy spectrum from a range of materials that are used to build dark matter detectors are calculated and tabulated. In addition to thorium and uranium decays, we found that $\\alpha$ particles from samarium that is often doped in the window material of photomultiplier (PMT) are also an important source of neutron yield. The results in this paper can be used as the input in the Monte Carlo simulation for many materials that will be used for next generation experiments.

  20. Results of the Search for Strange Quark Matter and Q-balls with the SLIM Experiment

    CERN Document Server

    Cecchini, S; Di Ferdinando, D; Errico, M; Fabbri, F; Giacomelli, G; Giacomelli, R; Giorgini, M; Kumar, A; McDonald, J; Mandrioli, G; Manzoor, S; Margiotta, A; Medinaceli, E; Patrizii, L; Pinfold, J L; Popa, V; Qureshi, I E; Saavedra, O; Sahnoun, Z; Sirri, G; Spurio, M; Togo, V; Valieri, C; Velarde, A; Zanini, A

    2008-01-01

    The SLIM experiment at the Chacaltaya high altitude laboratory was sensitive to nuclearites and Q-balls, which could be present in the cosmic radiation as possible Dark Matter components. It was sensitive also to strangelets, i.e. small lumps of Strange Quark Matter predicted at such altitudes by various phenomenological models. The analysis of 427 m^2 of Nuclear Track Detectors exposed for 4.22 years showed no candidate event. New upper limits on the flux of downgoing nuclearites and Q-balls at the 90% C.L. were established. The null result also restricts models for strangelets propagation through the Earth atmosphere.

  1. Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aprile, E.; Contreras, H.; Goetzke, L.W.; Fernandez, A.J.M.; Messina, M.; Plante, G.; Rizzo, A. [Columbia University, Physics Department, New York, NY (United States); Agostini, F. [INFN-Laboratori Nazionali del Gran Sasso (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Bologna Univ., Department of Physics and Astrophysics, Bologna (Italy); INFN, Bologna (Italy); Alfonsi, M. [Nikhef and the University of Amsterdam, Amsterdam (Netherlands); Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Arazi, L.; Budnik, R.; Duchovni, E.; Gross, E.; Itay, R.; Landsman, H.; Lellouch, D.; Levinson, L.; Priel, N.; Vitells, O. [Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel); Arisaka, K.; Lyashenko, A.; Meng, Y.; Pantic, E.; Teymourian, A.; Wang, H. [University of California, Physics and Astronomy Department, Los Angeles, CA (United States); Arneodo, F.; Di Giovanni, A. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Auger, M.; Barrow, P.; Baudis, L.; Behrens, A.; Galloway, M.; Kessler, G.; Kish, A.; Mayani, D.; Pakarha, P.; Piastra, F. [University of Zurich, Physik-Institut, Zurich (Switzerland); Balan, C.; Cardoso, J.M.R.; Lopes, J.A.M.; Santos, J.M.F. dos [University of Coimbra, Department of Physics, Coimbra (Portugal); Bauermeister, B.; Fattori, S.; Geis, C.; Grignon, C.; Oberlack, U.; Schindler, S. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Beltrame, P. [Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel); University of Edinburgh, Edinburgh (United Kingdom); Brown, A.; Lang, R.F.; Macmullin, S.; Pienaar, J.; Reichard, S.; Reuter, C. [Purdue University, Department of Physics and Astronomy, West Lafayette, IN (United States); Brown, E.; Levy, C. [Rensselaer Polytechnic Institute, Department of Physics, Applied Physics and Astronomy, Troy, NY (United States); Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Bruenner, S.; Hampel, W.; Kaether, F.; Lindemann, S.; Lindner, M.; Undagoitia, T.M.; Rauch, L.; Schreiner, J.; Simgen, H.; Weber, M. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Bruno, G. [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L' Aquila (Italy); Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Buetikofer, L.; Coderre, D.; Schumann, M. [University of Bern, Albert Einstein Center for Fundamental Physics, Bern (Switzerland); Colijn, A.P.; Decowski, M.P.; Tiseni, A.; Tunnell, C. [Nikhef and the University of Amsterdam, Amsterdam (Netherlands); Cussonneau, J.P.; Le Calloch, M.; Masbou, J.; Lavina, L.S.; Thers, D. [Universite de Nantes, Subatech, Ecole des Mines de Nantes, CNRS/In2p3, Nantes (France); Ferella, A.D.; Fulgione, W.; Laubenstein, M. [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L' Aquila (Italy); Fieguth, A.; Murra, M.; Rosendahl, S.; Weinheimer, C. [Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Garbini, M.; Massoli, F.V.; Sartorelli, G.; Selvi, M. [Bologna Univ., Department of Physics and Astrophysics, Bologna (Italy); INFN, Bologna (Italy); Miguez, B.; Molinario, A.; Trinchero, G. [INFN-Torino and Osservatorio Astrofisico di Torino, Turin (Italy); Naganoma, J.; Shagin, P.; Wall, R. [Rice University, Department of Physics and Astronomy, Houston, TX (United States); Orrigo, S.E.A. [University of Coimbra, Department of Physics, Coimbra (Portugal); IFIC, CSIC-Universidad de Valencia, Valencia (Spain); Persiani, R. [Universite de Nantes, Subatech, Ecole des Mines de Nantes, CNRS/In2p3, Nantes (FR); Bologna Univ., Department of Physics and Astrophysics, Bologna (IT); INFN, Bologna (IT); Collaboration: XENON Collaboration

    2015-11-15

    The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410 has been developed by Hamamatsu for dark matter direct detection experiments using liquid xenon as the target material. We present the results from the joint effort between the XENON collaboration and the Hamamatsu company to produce a highly radio-pure photosensor (version R11410-21) for the XENON1T dark matter experiment. After introducing the photosensor and its components, we show the methods and results of the radioactive contamination measurements of the individual materials employed in the photomultiplier production. We then discuss the adopted strategies to reduce the radioactivity of the various PMT versions. Finally, we detail the results from screening 286 tubes with ultra-low background germanium detectors, as well as their implications for the expected electronic and nuclear recoil background of the XENON1T experiment. (orig.)

  2. Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aprile, E. [Physics Department, Columbia University, New York, NY (United States); Agostini, F. [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L’Aquila (Italy); Department of Physics and Astrophysics, University of Bologna and INFN-Bologna, Bologna (Italy); Alfonsi, M. [Nikhef and the University of Amsterdam, Science Park, Amsterdam (Netherlands); Institut für Physik & Exzellenzcluster PRISMA, Johannes Gutenberg-Universität Mainz, Mainz (Germany); Arazi, L. [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot (Israel); Collaboration: XENON Collaboration; and others

    2015-11-23

    The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410 has been developed by Hamamatsu for dark matter direct detection experiments using liquid xenon as the target material. We present the results from the joint effort between the XENON collaboration and the Hamamatsu company to produce a highly radio-pure photosensor (version R11410-21) for the XENON1T dark matter experiment. After introducing the photosensor and its components, we show the methods and results of the radioactive contamination measurements of the individual materials employed in the photomultiplier production. We then discuss the adopted strategies to reduce the radioactivity of the various PMT versions. Finally, we detail the results from screening 286 tubes with ultra-low background germanium detectors, as well as their implications for the expected electronic and nuclear recoil background of the XENON1T experiment.

  3. Directional resolution of dish antenna experiments to search for WISPy dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Jaeckel, Joerg; Knirck, Stefan [Institut für theoretische Physik, Universität Heidelberg,Philosophenweg 16, 69120 Heidelberg (Germany)

    2016-01-04

    Dark matter consisting of very light and very weakly interacting particles such as axions, axion-like particles and hidden photons could be detected using reflective surfaces. On such reflectors some of the dark matter particles are converted into photons and, given a suitable geometry, concentrated on the detector. This technique offers sensitivity to the direction of the velocity of the dark matter particles. In this note we investigate how far spherical mirrors can concentrate the generated photons and what this implies for the resolution in directional detection as well as the sensitivity of discovery experiments not aiming for directional resolution. Finally we discuss an improved setup using a combination of a reflecting plane with focussing optics.

  4. Directional Resolution of Dish Antenna Experiments to Search for WISPy Dark Matter

    CERN Document Server

    Jaeckel, Joerg

    2015-01-01

    Dark matter consisting of very light and very weakly interacting particles such as axions, axion-like particles and hidden photons could be detected using reflective surfaces. On such reflectors some of the dark matter particles are converted into photons and, given a suitable geometry, concentrated on the detector. This technique offers sensitivity to the direction of the velocity of the dark matter particles. In this note we investigate how far spherical mirrors can concentrate the generated photons and what this implies for the resolution in directional detection as well as the sensitivity of discovery experiments not aiming for directional resolution. Finally we discuss an improved setup using a combination of a reflecting plane with focussing optics.

  5. Directional resolution of dish antenna experiments to search for WISPy dark matter

    Science.gov (United States)

    Jaeckel, Joerg; Knirck, Stefan

    2016-01-01

    Dark matter consisting of very light and very weakly interacting particles such as axions, axion-like particles and hidden photons could be detected using reflective surfaces. On such reflectors some of the dark matter particles are converted into photons and, given a suitable geometry, concentrated on the detector. This technique offers sensitivity to the direction of the velocity of the dark matter particles. In this note we investigate how far spherical mirrors can concentrate the generated photons and what this implies for the resolution in directional detection as well as the sensitivity of discovery experiments not aiming for directional resolution. Finally we discuss an improved setup using a combination of a reflecting plane with focussing optics.

  6. Action Video Game Experience Related to Altered Large-Scale White Matter Networks.

    Science.gov (United States)

    Gong, Diankun; Ma, Weiyi; Gong, Jinnan; He, Hui; Dong, Li; Zhang, Dan; Li, Jianfu; Luo, Cheng; Yao, Dezhong

    2017-01-01

    With action video games (AVGs) becoming increasingly popular worldwide, the cognitive benefits of AVG experience have attracted continuous research attention over the past two decades. Research has repeatedly shown that AVG experience can causally enhance cognitive ability and is related to neural plasticity in gray matter and functional networks in the brain. However, the relation between AVG experience and the plasticity of white matter (WM) network still remains unclear. WM network modulates the distribution of action potentials, coordinating the communication between brain regions and acting as the framework of neural networks. And various types of cognitive deficits are usually accompanied by impairments of WM networks. Thus, understanding this relation is essential in assessing the influence of AVG experience on neural plasticity and using AVG experience as an interventional tool for impairments of WM networks. Using graph theory, this study analyzed WM networks in AVG experts and amateurs. Results showed that AVG experience is related to altered WM networks in prefrontal networks, limbic system, and sensorimotor networks, which are related to cognitive control and sensorimotor functions. These results shed new light on the influence of AVG experience on the plasticity of WM networks and suggested the clinical applicability of AVG experience.

  7. Action Video Game Experience Related to Altered Large-Scale White Matter Networks

    Directory of Open Access Journals (Sweden)

    Diankun Gong

    2017-01-01

    Full Text Available With action video games (AVGs becoming increasingly popular worldwide, the cognitive benefits of AVG experience have attracted continuous research attention over the past two decades. Research has repeatedly shown that AVG experience can causally enhance cognitive ability and is related to neural plasticity in gray matter and functional networks in the brain. However, the relation between AVG experience and the plasticity of white matter (WM network still remains unclear. WM network modulates the distribution of action potentials, coordinating the communication between brain regions and acting as the framework of neural networks. And various types of cognitive deficits are usually accompanied by impairments of WM networks. Thus, understanding this relation is essential in assessing the influence of AVG experience on neural plasticity and using AVG experience as an interventional tool for impairments of WM networks. Using graph theory, this study analyzed WM networks in AVG experts and amateurs. Results showed that AVG experience is related to altered WM networks in prefrontal networks, limbic system, and sensorimotor networks, which are related to cognitive control and sensorimotor functions. These results shed new light on the influence of AVG experience on the plasticity of WM networks and suggested the clinical applicability of AVG experience.

  8. A simulation-based study of the neutron backgrounds for NaI dark matter experiments

    CERN Document Server

    Jeon, Eunju

    2015-01-01

    Among the direct search experiments for weakly interacting massive particle (WIMP) dark matter, the DAMA experiment observed an annual modulation signal interpreted as WIMP interactions with a significance of 9.2$\\sigma$. Recently, Jonathan Davis claimed that the DAMA modulation may be interpreted on the basis of the neutron scattering events induced by the muons and neutrinos together. We tried to simulate the neutron backgrounds at the Gran Sasso and Yangyang laboratory with and without the polyethylene shielding to quantify the effects of the ambient neutrons on the direct detection experiments based on the crystals.

  9. Effects of subject-area degree and classroom experience on new chemistry teachers' subject matter knowledge

    Science.gov (United States)

    Nixon, Ryan S.; Campbell, Benjamin K.; Luft, Julie A.

    2016-07-01

    Science teachers need to understand the subject matter they teach. While subject matter knowledge (SMK) can improve with classroom teaching experience, it is problematic that many secondary science teachers leave the profession before garnering extensive classroom experience. Furthermore, many new science teachers are assigned to teach science subjects for which they do not hold a degree. This study investigates the SMK of new secondary science teachers assigned to teach chemistry in their first three years of teaching. These new teachers do not have the advantage of years of experience to develop their SMK and half hold a degree in biology rather than chemistry. This qualitative study explores the effects of holding a degree in the subject area one teaches as well as classroom teaching experience on teachers' SMK for two chemistry topics, conservation of mass and chemical equilibrium. Qualitative analysis of semi-structured interviews indicated that the SMK of teachers who had a chemistry degree and more extensive classroom experience was more coherent, chemistry-focused, and sophisticated than that of teachers who lacked this preparation and experience. This study provides evidence that new science teachers' SMK is influenced by both holding a degree in the subject area and having classroom experience.

  10. Distinguishing Supersymmetry From Universal Extra Dimensions or Little Higgs Models With Dark Matter Experiments

    CERN Document Server

    Hooper, D; Hooper, Dan; Zaharijas, Gabrijela

    2007-01-01

    There are compelling reasons to think that new physics will appear at or below the TeV-scale. It is not known what form this new physics will take, however. Although The Large Hadron collider is very likely to discover new particles associated with the TeV-scale, it may be difficult for it to determine the nature of those particles, whether superpartners, Kaluza-Klein modes or other states. In this article, we consider how direct and indirect dark matter detection experiments may provide information complementary to hadron colliders, which can be used to discriminate between supersymmetry, models with universal extra dimensions, and Little Higgs theories. We find that, in many scenarios, dark matter experiments can be effectively used to distinguish between these possibilities.

  11. Characteristics and applications of isotopes in products from organic matter in sedimentary rocksby simulated thermal experiments

    Institute of Scientific and Technical Information of China (English)

    陈安定; 张文正; 徐永昌

    1995-01-01

    Isotopic compositions of carbon in the products obtained respectively from 25 sedimentary rocks at an early stage of maturation by the simulated thermogenetic hydrocarbons experiments have been determined. The fractional effect of methane carbon isotope during the thermal maturation of organic matter is observed. Based on the experimental data, the relative equations between δ13C and R0 were established and have been used for differentiation of origins of various kinds of natural gases in the Shan-Gan-Ning Basin.

  12. Ultra-fast X-ray absorption spectroscopy for the study of matter in transient regime; Spectroscopie d'absorption ultra-rapide de rayonnement X pour l'etude de la matiere en regime transitoire

    Energy Technology Data Exchange (ETDEWEB)

    Lecherbourg, L

    2007-12-15

    In this work, we study the physics of dense matter, plasmas or solids, using X-ray absorption spectroscopy. Through the use of sources produced by laser-matter interaction, we have measured the absorption spectra of aluminum and bromine plasmas, as well as those of vanadium dioxide (VO{sub 2}). The measurement of absorption coefficients allows us to probe the dense matter and to study its properties. The experiments are carried out following the same principle: they use the same experimental set-up, called pump-probe. When the matter is dense, the absorption properties of an atom are modified by the surrounding environment. In a plasma, it is mainly the bound- bound transitions which are altered: the shapes of those spectral rays are modified. In a solid, the position of the neighbouring atoms in relation to the absorbing atom modify the structure of absorption levels (bound-free transition). The study of this structure allows us to measure the parameters of the material, and provides information such as the state of the electronic band or the interatomic gaps. The experiments carried out at the LULI have allowed us to probe plasmas in the relatively unknown regime of the Warm Dense Matter. One of the key parameters is that the plasma is characterised independently (FDI diagnostic). It allows for a better comparison of the measured absorption against a calculation made with the numerical model OPA-S. The experiments carried out at INRS have led to the realisation of an experimental system having the characteristics which allow the study of the dynamics of solids showing ultra-fast phase transition. For those experiments, we have used vanadium dioxide as a model system allowing us to test the feasibility of the method. (author)

  13. Short-pulse, compressed ion beams at the Neutralized Drift Compression Experiment

    Science.gov (United States)

    Seidl, P. A.; Barnard, J. J.; Davidson, R. C.; Friedman, A.; Gilson, E. P.; Grote, D.; Ji, Q.; Kaganovich, I. D.; Persaud, A.; Waldron, W. L.; Schenkel, T.

    2016-05-01

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory, with 1-mm beam spot size within 2.5 ns full-width at half maximum. The ion kinetic energy is 1.2 MeV. To enable the short pulse duration and mm-scale focal spot radius, the beam is neutralized in a 1.5-meter-long drift compression section following the last accelerator cell. A short-focal-length solenoid focuses the beam in the presence of the volumetric plasma that is near the target. In the accelerator, the line-charge density increases due to the velocity ramp imparted on the beam bunch. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including select topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Below the transition to melting, the short beam pulses offer an opportunity to study the multi-scale dynamics of radiation-induced damage in materials with pump-probe experiments, and to stabilize novel metastable phases of materials when short-pulse heating is followed by rapid quenching. First experiments used a lithium ion source; a new plasma-based helium ion source shows much greater charge delivered to the target.

  14. Soil Organic Matter Dynamics in the Rothamsted Long-term Experiments

    Science.gov (United States)

    MacDonald, A.; Poulton, P.

    2009-04-01

    Soil science research at Rothamsted dates from 1843 when John Bennet Lawes and Joseph Henry Gilbert started the first of a series of what became long-term field experiments. The main object of these experiments was to examine the effect of inorganic and organic fertilisers and manures on crop yield and soil fertility. These "Classical Field Experiments" included studies on winter wheat (Broadbalk 1843), spring barley (Hoos Barley 1852) and permanent grassland (Park Grass 1856). Additional experiments were established in the 20th century to examine the value of ley-arable cropping, including the Highfield and Fosters Ley-arable experiments (1948) and the Woburn Ley-arable experiment (1938). More recently, the effects of incorporating organic manures and cereal straw have been examined. Early results quickly showed the benefits of inorganic N and P fertilisers on crop production, but the effects of contrasting land uses and management practices on soil properties emerged more slowly. Measurements of soil organic carbon (C) and nitrogen (N) in soils taken at intervals from the long-term experiments indicate that the rate of soil organic matter (SOM) accumulation is controlled largely by the balance between the rate of organic matter inputs and its oxidation rate, and that these are strongly influenced by land use and management, soil texture (especially clay content) and climate. A recent examination of soil organic C data from two long-term grassland experiments in the UK (including Park Grass) indicates that any changes observed in soil organic C under long-term grasslands over the past 40 years are more likely to be due to changes in land use and management rather than climate change. Data from the Rothamsted Long-term experiments have been used to develop and test biogeochemical models of C and N dynamics. In particular, the Roth-C model has successfully simulated soil C dynamics in the long-term experiments at Rothamsted and elsewhere. This model uses several

  15. Detector Simulation and WIMP Search Analysis for the Cryogenic Dark Matter Search Experiment

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, Kevin [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2013-06-01

    Astrophysical and cosmological measurements on the scales of galaxies, galaxy clusters, and the universe indicate that 85% of the matter in the universe is composed of dark matter, made up of non-baryonic particles that interact with cross-sections on the weak scale or lower. Hypothetical Weakly Interacting Massive Particles, or WIMPs, represent a potential solution to the dark matter problem, and naturally arise in certain Standard Model extensions. The Cryogenic Dark Matter Search (CDMS) collaboration aims to detect the scattering of WIMP particles from nuclei in terrestrial detectors. Germanium and silicon particle detectors are deployed in the Soudan Underground Laboratory in Minnesota. These detectors are instrumented with phonon and ionization sensors, which allows for discrimination against electromagnetic backgrounds, which strike the detector at rates orders of magnitude higher than the expected WIMP signal. This dissertation presents the development of numerical models of the physics of the CDMS detectors, implemented in a computational package collectively known as the CDMS Detector Monte Carlo (DMC). After substantial validation of the models against data, the DMC is used to investigate potential backgrounds to the next iteration of the CDMS experiment, known as SuperCDMS. Finally, an investigation of using the DMC in a reverse Monte Carlo analysis of WIMP search data is presented.

  16. Positronium Portal into Hidden Sector: A new Experiment to Search for Mirror Dark Matter

    CERN Document Server

    Crivelli, Paolo; Gendotti, Ulisse; Gninenko, Sergei; Rubbia, Andre

    2010-01-01

    The understanding of the origin of dark matter has great importance for cosmology and particle physics. Several interesting extensions of the standard model dealing with solution of this problem motivate the concept of hidden sectors consisting of SU(3)xSU(2)_LxU(1)_Y singlet fields. Among these models, the mirror matter model is certainly one of the most interesting. The model explains the origin of parity violation in weak interactions, it could also explain the baryon asymmetry of the Universe and provide a natural ground for the explanation of dark matter. The mirror matter could have a portal to our world through photon-mirror photon mixing (epsilon). This mixing would lead to orthopositronium (o-Ps) to mirror orthopositronium oscillations, the experimental signature of which is the apparently invisible decay of o-Ps. In this paper, we describe an experiment to search for the decay o-Ps -> invisible in vacuum by using a pulsed slow positron beam and a massive 4pi BGO crystal calorimeter. The developed hi...

  17. Radon Mitigation for the SuperCDMS-SNOLAB Dark Matter Experiment

    Science.gov (United States)

    Street, Joseph; SuperCDMS Collaboration

    2016-03-01

    Experiments that seek to detect very rare processes, such as interactions of the dark matter particles thought to make up 85% of the mass of the universe, may suffer background interactions from radon daughters that have plated out onto detector surfaces. To reduce these backgrounds, an ultra-low-radon cleanroom was built at the South Dakota School of Mines & Technology. Cleanroom air is supplied by an optimized vacuum-swing-adsorption radon mitigation system that has achieved a > 300 × reduction from an input activity of 58.6 +/- 0.7 Bq/m3 to a cleanroom activity of 0.13 +/- 0.06 Bq/m3. Expected backgrounds due to radon daughters for the SuperCDMS dark matter search will be presented.

  18. The WArP Experiment: A Double-Phase Argon Detector for Dark Matter Searches

    Directory of Open Access Journals (Sweden)

    Andrea Zani

    2014-01-01

    Full Text Available Cryogenic noble liquids emerged in the previous decade as one of the best media to perform WIMP dark matter searches, in particular due to the possibility to scale detector volumes to multiton sizes. The WArP experiment was then developed as one of the first to implement the idea of coupling Argon in liquid and gas phase, in order to discriminate β/γ-interactions from nuclear recoils and then achieve reliable background rejection. Since its construction, other projects spawned, employing Argon and Xenon and following its steps. The WArP 100l detector was assembled in 2008 at the Gran Sasso National Laboratories (LNGS, as the final step of a years-long R&D programme, aimed at characterising the technology of Argon in double phase for dark matter detection. Though it never actually performed a physics run, a technical run was taken in 2011, to characterise the detector response.

  19. a Next-Generation Cavity Microwave Experiment to Search for Dark-Matter Axions

    Science.gov (United States)

    Bibber, K. Van; Stöffl, W.; Anthony, P. L.; Sikivie, P.; Sullivan, N. S.; Tanner, D. B.; Železný, V.; Golubev, N. A.; Kazachenko, O. V.; Kravchuk, L. V.; Kuzmin, V.; Romanov, G. V.; Sekachev, I. V.; Rosenberg, L. J.; Hagmann, C.; Moltz, D. M.; Nezrick, F.; Turner, M. S.; Villa, F.

    We propose a large-scale experimental search for dark-matter axions which may constitute an important fraction of our own galactic halo. As shown by Sikivie,1 dark-matter axions may be detected by their stimulated conversion into monochromatic microwave photons in a tunable high-Q cavity inside a strong magnetic field. The principal improvement in power sensitivity over two earlier pilot experiments (×25) derives from the large-volume high field superconducting magnet (the NASA SUMMA coils). The improvement in mass range (1.5 to 12.6 μeV) will result from the use of several microwave cavity arrays, of 2n cavities each, over the course of the experimental program, rather than a single cavity. We are participating in a joint venture with the Institute for Nuclear Research of the Russian Academy of Sciences to do R&D on metalized precision-formed ceramic microwave cavities for the axion search.

  20. The Cryogenic Dark Matter Search (CDMS-II) Experiment: First Results from the Soudan Mine

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Clarence Leeder [Stanford Univ., CA (United States)

    2004-09-01

    There is an abundance of evidence that the majority of the mass of the universe is in the form of non-baryonic non-luminous matter that was non-relativistic at the time when matter began to dominate the energy density. Weakly Interacting Massive Particles, or WIMPs, are attractive cold dark matter candidates because they would have a relic abundance today of ~0.1 which is consistent with precision cosmological measurements. WIMPs are also well motivated theoretically. Many minimal supersymmetric extensions of the Standard Model have WIMPs in the form of the lightest supersymmetric partner, typically taken to be the neutralino. The CDMS II experiment searches for WIMPs via their elastic scattering off of nuclei. The experiment uses Ge and Si ZIP detectors, operated at <50 mK, which simultaneously measure the ionization and athermal phonons produced by the scattering of an external particle. The dominant background for the experiment comes from electromagnetic interactions taking place very close to the detector surface. Analysis of the phonon signal from these interactions makes it possible to discriminate them from interactions caused by WIMPs. This thesis presents the details of an important aspect of the phonon pulse shape analysis known as the ''Lookup Table Correction''. The Lookup Table Correction is a position dependent calibration of the ZIP phonon response which improves the rejection of events scattering near the detector surface. The CDMS collaboration has recently commissioned its experimental installation at the Soudan Mine. This thesis presents an analysis of the data from the first WIMP search at the Soudan Mine. The results of this analysis set the world's lowest exclusion limit making the CDMS II experiment at Soudan the most sensitive WIMP search to this date.

  1. The Axion Dark Matter Experiment: Big Science with a (relatively) Small Team

    Science.gov (United States)

    Carosi, Gianpaolo

    2016-03-01

    The idea of the solitary physicist tinkering alone in a lab was my image of how science was done growing up (mostly influenced by popular culture). Of course this is not generally how experimental physics is done now days with examples of experiments at the LHC now involving thousands of scientists. In this talk I will describe my experience in a relatively modest project, the Axion Dark Matter eXperiment (ADMX), which involves only a few dozen scientists at various universities and national labs. I will outline ADMX's humble beginnings at Lawrence Livermore National Laboratory (LLNL), where it began in the mid-1990s, and describe how the collaboration has evolved and grown throughout the years, as we pursue our elusive quarry: the dark-matter axion. Supported by DOE Grants DE-FG02-97ER41029, DE-FG02-96ER40956, DE- AC52-07NA27344, DE-AC03-76SF00098, and the Livermore LDRD program.

  2. Observational constraints of stellar collapse: Diagnostic probes of nature's extreme matter experiment

    Directory of Open Access Journals (Sweden)

    Chris L. Fryer

    2014-04-01

    Full Text Available Supernovae are Nature's high-energy, high density laboratory experiments, reaching densities in excess of nuclear densities and temperatures above 10 MeV. Astronomers have built up a suite of diagnostics to study these supernovae. If we can utilize these diagnostics, and tie them together with a theoretical understanding of supernova physics, we can use these cosmic explosions to study the nature of matter at these extreme densities and temperatures. Capitalizing on these diagnostics will require understanding a wide range of additional physics. Here we review the diagnostics and the physics neeeded to use them to learn about the supernova engine, and ultimate nuclear physics.

  3. Observational Constraints of Stellar Collapse: Diagnostic Probes of Nature's Extreme Matter Experiment

    CERN Document Server

    Fryer, C L; Grefenstette, B W; Wong, T -W

    2014-01-01

    Supernovae are Nature's high-energy, high density laboratory experiments, reaching densities in excess of nuclear densities and temperatures above 10MeV. Astronomers have built up a suite of diagnostics to study these supernovae. If we can utilize these diagnostics, and tie them together with a theoretical understanding of supernova physics, we can use these cosmic explosions to study the nature of matter at these extreme densities and temperatures. Capitalizing on these diagnostics will require understanding a wide range of additional physics. Here we review the diagnostics and the physics needed to use them to learn about the supernova engine, and ultimate nuclear physics.

  4. CALIS - a CALibration Insertion System for the DarkSide-50 dark matter search experiment

    Energy Technology Data Exchange (ETDEWEB)

    Agnes, P.; et al.

    2012-12-28

    This paper describes the design, fabrication, commissioning and use of a CALibration source Insertion System (CALIS) in the DarkSide-50 direct dark matter search experiment. CALIS deploys radioactive sources into the liquid scintillator veto to characterize the detector response and detection efficiency of the DarkSide-50 Liquid Argon Time Projection Chamber, and the surrounding 30 t organic liquid scintillator neutron veto. It was commissioned in September 2014 and has been used successfully in several gamma and neutron source campaigns since then. A description of the hardware and an excerpt of calibration analysis results are given below.

  5. CALIS - a CALibration Insertion System for the DarkSide-50 dark matter search experiment

    CERN Document Server

    Agnes, P; Alexander, T; Alton, A K; Asner, D M; Back, H O; Baldin, B; Biery, K; Bocci, V; Bonfini, G; Bonivento, W; Bossa, M; Bottino, B; Brigatti, A; Brodsky, J; Budano, F; Bussino, S; Cadeddu, M; Cadonati, L; Cadoni, M; Calaprice, F; Canci, N; Candela, A; Caravati, M; Cariello, M; Carlini, M; Catalanotti, S; Cavalcante, P; Chepurnov, A; Cicalo, C; Cocco, A G; Covone, G; D'Angelo, D; D'Incecco, M; Davini, S; De Cecco, S; De Deo, M; De Vincenzi, M; Derbin, A; Devoto, A; Di Eusanio, F; Di Pietro, G; Dionisi, C; Edkins, E; Empl, A; Fan, A; Fiorillo, G; Fomenko, K; Forster, G; Franco, D; Gabriele, F; Galbiati, C; Giagu, S; Giganti, C; Giovanetti, G K; Goretti, A M; Granato, F; Grandi, L; Gromov, M; Guan, M; Guardincerri, Y; Hackett, B R; Herner, K; Hughes, D; Humble, P; Hungerford, E V; Ianni, Al; Ianni, An; James, I; Johnson, T N; Jollet, C; Keeter, K; Kendziora, C L; Koh, G; Korablev, D; Korga, G; Kubankin, A; Li, X; Lissia, M; Loer, B; Lombardi, P; Longo, G; Ma, Y; Machulin, I N; Mandarano, A; Mari, S M; Maricic, J; Marini, L; Martoff, C J; Meregaglia, A; Meyers, P D; Milincic, R; Miller, J D; Montanari, D; Monte, A; Mount, B J; Muratova, V N; Musico, P; Napolitano, J; Agasson, A Navrer; Odrowski, S; Orsini, M; Ortica, F; Pagani, L; Pallavicini, M; Pantic, E; Parmeggiano, S; Pelczar, K; Pelliccia, N; Pocar, A; Pordes, S; Pugachev, D A; Qian, H; Randle, K; Ranucci, G; Razeti, M; Razeto, A; Reinhold, B; Renshaw, A L; Rescigno, M; Riffard, Q; Romani, A; Rossi, B; Rossi, N; Rountree, D; Sablone, D; Saggese, P; Saldanha, R; Sands, W; Savarese, C; Schlitzer, B; Segreto, E; Semenova, D A; Shields, E; Singh, P N; Skorokhvatov, M D; Smirnov, O; Sotnikov, A; Stanford, C; Suvorov, Y; Tartaglia, R; Tatarowicz, J; Testera, G; Tonazzo, A; Trinchese, P; Unzhakov, E V; Verducci, M; Vishneva, A; Vogelaar, B; Wada, M; Walker, S; Wang, H; Wang, Y; Watson, A W; Westerdale, S; Wilhelmi, J; Wojcik, M M; Xiang, Xi; Xiao, X; Xu, J; Yang, C; Zec, A; Zhong, W; Zhu, C; Zuzel, G

    2016-01-01

    This paper describes the design, fabrication, commissioning and use of a CALibration source Insertion System (CALIS) in the DarkSide-50 direct dark matter search experiment. CALIS deploys radioactive sources into the liquid scintillator veto to characterize the detector response and detection efficiency of the DarkSide-50 Liquid Argon Time Projection Chamber, and the surrounding 30 t organic liquid scintillator neutron veto. It was commissioned in September 2014 and has been used successfully in several gamma and neutron source campaigns since then. A description of the hardware and an excerpt of calibration analysis results are given below.

  6. Organic matter degradation in Chilean sediments - following nature's own degradation experiment

    DEFF Research Database (Denmark)

    Langerhuus, Alice Thoft; Niggemann, Jutta; Lomstein, Bente Aagaard

    .000 year old sediments. Since the microbial activity in the deep sediments is very low, it is still not possible to measure it directly. Following nature’s own experiment back in time will provide us with new insights about the microbial activity in the deeply buried sediments. Poster presentation Session...... in length, respectively. The objective of this study was to assess the degradability of the organic matter from the sediment surface to the deep sediments. This was done by analysing amino acids (both L- and D-isomers) and amino sugars in the sediment cores, covering a timescale of 15.000 years. Diagenetic...

  7. General experiments concerning particle-matter interactions; Experiences interdisciplinaires d'interaction particule-matiere

    Energy Technology Data Exchange (ETDEWEB)

    Dauvergne, D

    2006-07-15

    The author gathers in this document several papers he has already published in order to shed light on different aspects concerning ion-crystal interactions. This document is divided into 3 chapters. In the first chapter the author presents results obtained from experiments dedicated to charge exchanges and energy released by heavy ions in channeling conditions. Different processes involved in ion-electron interactions are considered: The tri-electronic recombination, the electron capture through nuclear excitation (NEEC), resonant transfer and excitation (RTE), resonant transfer and double excitation (RTDE) and electron impact ionization (EII). The second chapter deals with the measurement of nuclear fission times through crystal blocking experiments. The crystal blocking technique allows the measurement in a model-independent way of the recoil distance covered by the excited nucleus during the whole fission process (starting from the initial collision and ending at the scission point). The last chapter is dedicated to the photon impact ionization through the conversion of a high-energy photon into an electron-positron pair.

  8. Dark matter in Draco and the Local Group Implications for direct detection experiments

    CERN Document Server

    Moore, B; Stadel, J; Quinn, T; Lake, G; Ghigna, S; Governato, F; Moore, Ben; Calcaneo-Roldan, Carlos; Stadel, Joachim; Quinn, Tom; Lake, George; Ghigna, Sebastiano; Governato, Fabio

    2001-01-01

    We use a cosmological simulation of the Local Group to make quantitative and speculative predictions for direct detection experiments. Cold dark matter (CDM) halos form via a complex series of mergers, accretion events and violent relaxation which precludes the formation of significant caustic features predicted by axially symmetric collapse. The halo density profiles are combined with observational constraints on the galactic mass distribution to constrain the local density of cold dark matter to lie in the range 0.18 <~ rho_CDM(R_solar)/GeV cm^-3 <~ 0.30. In velocity space, coherent streams of dark matter from tidally disrupted halos fill the halo and provide a tracer of the merging hierarchy. The particle velocities within triaxial CDM halos cannot be approximated by a simple Maxwellian distribution and is radially biased at the solar position. The detailed phase space structure within the solar system will depend on the early merger history of the progenitor halos and the importance of major mergers...

  9. A Low-Threshold Analysis of Data from the Cryogenic Dark Matter Search Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Bunker, Raymond [Univ. of California, Santa Barbara, CA (United States)

    2011-12-01

    Although dark matter appears to constitute over 80% of the matter in the Universe, its composition is a mystery. Astrophysical observations suggest that the luminous portions of the Galaxy are embedded in a halo of darkmatter particles. Weakly Interacting Massive Particles (WIMPs) are the most studied class of dark-matter candidates and arise naturally within the context of many weak-scale supersymmetric theories. Direct-detection experiments like the Cryogenic Dark Matter Search (CDMS) strive to discern the kinetic energy of recoiling nuclei resulting from WIMP interactions with terrestrial matter. This is a considerable challenge in which the low (expected) rate of WIMP interactions must be distinguished from an overwhelming rate due to known types of radiation. An incontrovertible positive detection has remained elusive. However, a few experiments have recorded data that appear consistent with a low-mass WIMP. This thesis describes an attempt to probe the favored parameter space. To increase sensitivity to low-mass WIMPs, a low-threshold technique with improved sensitivity to small energy depositions is applied to CDMS shallowsite data. Four germanium and two silicon detectors were operated between December 2001 and June 2002, yielding 118 days of exposure. By sacrificing some of the CDMS detectors’ ability to discriminate signal from background, energy thresholds of ~1 and ~2 keV were achieved for three of the germanium and both silicon detectors, respectively. A large number of WIMP candidate events are observed, most of which can be accounted for by misidentification of background sources. No conclusive evidence for a low-mass WIMP signal is found. The observed event rates are used to set upper limits on the WIMPnucleon scattering cross section as a function of WIMP mass. Interesting parameter space is excluded for WIMPs with masses below ~9GeV/c2. Under standard assumptions, the parameter space favored by interpretations of other experiments

  10. What can(not) be measured with ton-scale dark matter direct detection experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pato, Miguel, E-mail: migpato@physik.uzh.ch [Institute for Theoretical Physics, University of Zürich, Winterthurerstrasse 190, CH-8057 (Switzerland)

    2011-10-01

    Direct searches for dark matter have prompted in recent years a great deal of excitement within the astroparticle physics community, but the compatibility between signal claims and null results of different experiments is far from being a settled issue. In this context, we study here the prospects for constraining the dark matter parameter space with the next generation of ton-scale detectors. Using realistic experimental capabilities for a wide range of targets (including fluorine, sodium, argon, germanium, iodine and xenon), the role of target complementarity is analysed in detail while including the impact of astrophysical uncertainties in a self-consistent manner. We show explicitly that a multi-target signal in future direct detection facilities can determine the sign of the ratio of scalar couplings f{sub n}/f{sub p}, but not its scale. This implies that the scalar-proton cross-section is left essentially unconstrained if the assumption f{sub p} ∼ f{sub n} is relaxed. Instead, we find that both the axial-proton cross-section and the ratio of axial couplings a{sub n}/a{sub p} can be measured with fair accuracy if multi-ton instruments using sodium and iodine will eventually come online. Moreover, it turns out that future direct detection data can easily discriminate between elastic and inelastic scatterings. Finally, we argue that, with weak assumptions regarding the WIMP couplings and the astrophysics, only the dark matter mass and the inelastic parameter (i.e. mass splitting) may be inferred from the recoil spectra — specifically, we anticipate an accuracy of tens of GeV (tens of keV) in the measurement of the dark matter mass (inelastic parameter)

  11. Recent Experiments At Ndcx-II: Irradiation Of Materials Using Short, Intense Ion Beams

    CERN Document Server

    Seidl, P A; Persaud, A; Feinberg, E; Ludewigt, B; Silverman, M; Sulyman, A; Waldron, W L; Schenkel, T; Barnard, J J; Friedman, A; Grote, D P; Gilson, E P; Kaganovich, I D; Stepanov, A; Treffert, F; Zimmer, M

    2016-01-01

    We present an overview of the performance of the Neutralized Drift Compression Experiment-II (NDCX-II) accelerator at Berkeley Lab, and summarize recent studies of material properties created with nanosecond and millimeter-scale ion beam pulses. The scientific topics being explored include the dynamics of ion induced damage in materials, materials synthesis far from equilibrium, warm dense matter and intense beam-plasma physics. We summarize the improved accelerator performance, diagnostics and results of beam-induced irradiation of thin samples of, e.g., tin and silicon. Bunches with over 3x10^10 ions, 1- mm radius, and 2-30 ns FWHM duration have been created. To achieve these short pulse durations and mm-scale focal spot radii, the 1.2 MeV He+ ion beam is neutralized in a drift compression section which removes the space charge defocusing effect during final compression and focusing. Quantitative comparison of detailed particle-in-cell simulations with the experiment play an important role in optimizing acc...

  12. Short-Pulse, Compressed Ion Beams at the Neutralized Drift Compression Experiment

    CERN Document Server

    Seidl, Peter A; Davidson, Ronald C; Friedman, Alex; Gilson, Erik P; Grote, David; Ji, Qing; Kaganovich, I D; Persaud, Arun; Waldron, William L; Schenkel, Thomas

    2016-01-01

    We have commenced experiments with intense short pulses of ion beams on the Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory, with 1-mm beam spot size within 2.5 ns full-width at half maximum. The ion kinetic energy is 1.2 MeV. To enable the short pulse duration and mm-scale focal spot radius, the beam is neutralized in a 1.5-meter-long drift compression section following the last accelerator cell. A short-focal-length solenoid focuses the beam in the presence of the volumetric plasma that is near the target. In the accelerator, the line-charge density increases due to the velocity ramp imparted on the beam bunch. The scientific topics to be explored are warm dense matter, the dynamics of radiation damage in materials, and intense beam and beam-plasma physics including select topics of relevance to the development of heavy-ion drivers for inertial fusion energy. Below the transition to melting, the short beam pulses offer an opportunity to study the multi-scale dynam...

  13. Constraints on the Interactions between Dark Matter and Baryons from the X-ray Quantum Calorimetry Experiment

    CERN Document Server

    Erickcek, Adrienne L; McCammon, Dan; McGuire, Patrick C

    2007-01-01

    Although the rocket-based X-ray Quantum Calorimetry (XQC) experiment was designed for X-ray spectroscopy, the minimal shielding of its calorimeters, its low atmospheric overburden, and its low-threshold detectors make it among the most sensitive instruments for detecting or constraining strong interactions between dark matter particles and baryons. We use Monte Carlo simulations to obtain the precise limits the XQC experiment places on spin-independent interactions between dark matter and baryons, improving upon earlier analytical estimates. We find that the XQC experiment rules out a wide range of nucleon-scattering cross sections centered around one barn for dark matter particles with masses between 0.01 and 10^5 GeV. Our analysis also provides new constraints on cases where only a fraction of the dark matter strongly interacts with baryons.

  14. Investigation of water-soluble organic matter extracted from shales during leaching experiments

    Science.gov (United States)

    Zhu, Yaling; Vieth-Hillebrand, Andrea; Wilke, Franziska D. H.; Horsfield, Brian

    2017-04-01

    The huge volumes and unknown composition of flowback and produced waters cause major public concerns about the environmental and social compatibility of hydraulic fracturing and the exploitation of gas from unconventional reservoirs. Flowback and produced waters contain not only residues of fracking additives but also chemical species that are dissolved from the shales themselves during fluid-rock interaction. Knowledge of the composition, size and structure of dissolved organic carbon (DOC) as well as the main controls on the release of DOC are a prerequisite for a better understanding of these interactions and its effects on composition of flowback and produced water. Black shales from four different geological settings and covering a maturity range Ro = 0.3-2.6% were extracted with deionized water. The DOC yields were found to decrease rapidly with increasing diagenesis and remain low throughout catagenesis. Four DOC fractions have been qualitatively and quantitatively characterized using size-exclusion chromatography. The concentrations of individual low molecular weight organic acids (LMWOA) decrease with increasing maturity of the samples except for acetate extracted from the overmature Posidonia shale, which was influenced by hydrothermal brines. The oxygen content of the shale organic matter also shows a significant influence on the release of organic acids, which is indicated by the positive trend between oxygen index (OI) and the concentrations of formate and acetate. Based on our experiments, both the properties of the organic matter source and the thermal maturation progress of the shale organic matter significantly influence the amount and quality of extracted organic compounds during the leaching experiments.

  15. PandaX: a liquid xenon dark matter experiment at CJPL

    Science.gov (United States)

    Cao, XiGuang; Chen, Xun; Chen, YunHua; Cui, XiangYi; Fang, DeQing; Fu, ChangBo; Giboni, Karl L.; Gong, HaoWei; Guo, GuoDong; He, Ming; Hu, Jie; Huang, XingTao; Ji, XiangDong; Ju, YongLin; Li, ShaoLi; Lin, Qing; Liu, HuaXuan; Liu, JiangLai; Liu, Xiang; Lorenzon, Wolfgang; Ma, YuGang; Mao, YaJun; Ni, KaiXuan; Pushkin, Kirill; Ren, XiangXiang; Schubnell, Michael; Shen, ManBing; Shi, YuJie; Stephenson, Scott; Tan, AnDi; Tarlé, Greg; Wang, HongWei; Wang, JiMing; Wang, Meng; Wang, XuMing; Wang, Zhou; Wei, YueHuan; Wu, ShiYong; Xiao, MengJiao; Xiao, Xiang; Xie, PengWei; Ye, Tao; You, YingHui; Zen, XiongHui; Zhang, Hua; Zhang, Tao; Zhao, HaiYing; Zhao, Li; Zhou, XiaoPeng; Zhu, ZhongHua

    2014-08-01

    PandaX is a large liquid-xenon detector experiment usable for direct dark-matter detection and 136Xe double-beta decay search. The central vessel was designed to accommodate a staged target volume increase from initially 120 kg (stage I) to 0.5 t (stage II) and eventually to a multi-ton scale. The experiment is located in the Jinping Deep-Underground Laboratory in Sichuan, China. The detector operates in dual-phase mode, allowing detection of both prompt scintillation, and ionization charge through proportional scintillation. In this paper a detailed description of the stage I detector design and performance as well as results established during the commissioning phase are presented.

  16. Operating the GridPix detector in dark matter search experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schön, R., E-mail: rolfs@nikhef.nl [National Institute for Subatomic Physics Nikhef, Science Park 105, 1098 XG, Amsterdam (Netherlands); Alfonsi, M. [National Institute for Subatomic Physics Nikhef, Science Park 105, 1098 XG, Amsterdam (Netherlands); Hemink, G. [National Institute for Subatomic Physics Nikhef, Science Park 105, 1098 XG, Amsterdam (Netherlands); University of Twente, Drienerloolaan 5, 7522 NB, Enschede (Netherlands); Decowski, M.P.; Bakel, N. van; Graaf, H. van der [National Institute for Subatomic Physics Nikhef, Science Park 105, 1098 XG, Amsterdam (Netherlands)

    2013-08-01

    The DARWIN (dark matter WIMP search with noble liquids) design study aims to use liquid argon and liquid xenon targets to look for nuclear recoils due to weakly interacting massive particles (WIMPs). To measure the recoil energy in dual-phase noble gas time projection chambers the combination of scintillation and ionisation detection is used to discriminate nuclear from electron recoils. Current experiments use an array of photomultiplier tubes to detect the primary scintillation and the ionisation electrons via secondary scintillation in the gas phase. Within the research framework for DARWIN, one candidate for an alternative direct charge readout is GridPix, a micro-pattern gaseous detector composed of a Micromegas-like amplification grid over the Timepix 65k pixel readout chip. It can achieve a single-electron detection efficiency of up to 98% and has thus great potential to identify the ionisation electrons in dark matter search experiments. The main challenges for this application are low outgassing, thermal robustness, and operation in pure (thus quencher-free) noble gas. To investigate its applicability we operated a GridPix detector in an argon cryostat. We proved GridPix's performance in pure argon. The gas amplification was confirmed in pure argon in the broad temperature range from 300 K down to 87 K. Additionally, we discuss results of thermal tests of GridPix devices at liquid xenon temperature in a dry nitrogen atmosphere.

  17. First Results from the Cryogenic Dark Matter Search Experiment at the Deep Site

    Energy Technology Data Exchange (ETDEWEB)

    Mandic, Vuk [Univ. of California, Berkeley, CA (United States)

    2004-06-01

    The Cryogenic Dark Matter Search (CDMS) experiment is designed to search for dark matter in the form of the Weakly Interacting Massive Particles (WIMPs). For this purpose, CDMS uses detectors based on crystals of Ge and Si, operated at the temperature of 20 mK, and providing a two-fold signature of an interaction: the ionization and the athermal phonon signals. The two signals, along with the passive and active shielding of the experimental setup, and with the underground experimental sites, allow very effective suppression and rejection of different types of backgrounds. This dissertation presents the commissioning and the results of the first WIMP-search run performed by the CDMS collaboration at the deep underground site at the Soudan mine in Minnesota. We develop different methods of suppressing the dominant background due to the electron-recoil events taking place at the detector surface and we apply these algorithms to the data set. These results place the world's most sensitive limits on the WIMP-nucleon spin-independent elastic-scattering cross-section. Finally, they examine the compatibility of the supersymmetric WIMP-models with the direct-detection experiments (such as CDMS) and discuss the implications of the new CDMS result on these models.

  18. "What matters most:" a cultural mechanism moderating structural vulnerability and moral experience of mental illness stigma.

    Science.gov (United States)

    Yang, Lawrence H; Chen, Fang-pei; Sia, Kathleen Janel; Lam, Jonathan; Lam, Katherine; Ngo, Hong; Lee, Sing; Kleinman, Arthur; Good, Byron

    2014-02-01

    To understand Chinese immigrants' experiences with mental illness stigma and mental health disparities, we integrate frameworks of 'structural vulnerability' and 'moral experience' to identify how interaction between structural discrimination and cultural engagements might shape stigma. Fifty Chinese immigrants, including 64% Fuzhounese immigrants who experienced particularly harsh socio-economical deprivation, from two Chinese bilingual psychiatric inpatient units in New York City were interviewed from 2006 to 2010 about their experiences of mental illness stigma. Interview questions were derived from 4 stigma measures, covering various life domains. Participants were asked to elaborate their rating of measure items, and thus provided open-ended, narrative data. Analysis of the narrative data followed a deductive approach, guided by frameworks of structural discrimination and "what matters most" - a cultural mechanism signifying meaningful participation in the community. After identifying initial coding classifications, analysis focused on the interface between the two main concepts. Results indicated that experiences with mental illness stigma were contingent on the degree to which immigrants were able to participate in work to achieve "what mattered most" in their cultural context, i.e., accumulation of financial resources. Structural vulnerability - being situated in an inferior position when facing structural discrimination - made access to affordable mental health services challenging. As such, structural discrimination increased healthcare spending and interfered with financial accumulation, often resulting in future treatment nonadherence and enforcing mental health disparities. Study participants' internalizing their structurally-vulnerable position further led to a depreciated sense of self, resulting in a reduced capacity to advocate for healthcare system changes. Paradoxically, the multi-layered structural marginalization experienced by Chinese

  19. Dark Matter Search in a Beam-Dump eXperiment (BDX) at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Battaglieri, M. [Univ. of Genova (Italy). National Institute for Nuclear Physics. et al

    2016-07-05

    MeV-GeV dark matter (DM) is theoretically well motivated but remarkably unexplored. This proposal presents the MeV-GeV DM discovery potential for a $\\sim$1 m$^3$ segmented CsI(Tl) scintillator detector placed downstream of the Hall A beam-dump at Jefferson Lab, receiving up to 10$^{22}$ electrons-on-target (EOT) in 285 days. This experiment (Beam-Dump eXperiment or BDX) would be sensitive to elastic DM-electron and to inelastic DM scattering at the level of 10 counts per year, reaching the limit of the neutrino irreducible background. The distinct signature of a DM interaction will be an electromagnetic shower of few hundreds of MeV, together with a reduced activity in the surrounding active veto counters. A detailed description of the DM particle $\\chi$ production in the dump and subsequent interaction in the detector has been performed by means of Monte Carlo simulations. Different approaches have been used to evaluate the expected backgrounds: the cosmogenic background has been extrapolated from the results obtained with a prototype detector running at INFN-LNS (Italy), while the beam-related background has been evaluated by GEANT4 Monte Carlo simulations. The proposed experiment will be sensitive to large regions of DM parameter space, exceeding the discovery potential of existing and planned experiments in the MeV-GeV DM mass range by up to two orders of magnitude.

  20. The distribution of tritium between water and suspended matter in a laboratory experiment exposing sediment to tritiated water.

    Science.gov (United States)

    Jean-Baptiste, Philippe; Fourré, Elise

    2013-02-01

    Following recent suggestions regarding the strong affinity of tritiated water for organic matter in suspended particulates and sediments, two equilibration experiments between sediment organic matter (dry and fresh) and tritiated water were performed to look for potential tritium bio-concentration. The T/H ratios measured at the end of both experiments are lower in the sediment organic matter than in the water, indicating that only a fraction of the hydrogen pool (between 14% and 20%) within the sediment equilibrated with the tritiated water. These results are consistent with the widely used concept of exchangeable and non-exchangeable tritium pools in organic matter and show no sign of tritium bio-accumulation in the sediment relative to water. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. VUV light reflectivity measurements from PTFE in Liquid Xenon for the LZ Dark Matter experiment

    Science.gov (United States)

    Pushkin, Kirill; LZ Collaboration

    2016-03-01

    The LUX-Zeplin (LZ) collaboration is the next generation of the experiment to search for Dark Matter in the Universe with a dual-phase detector based on liquid xenon (LXe) with a target mass of 7 ton. LXe dual phase detectors are very sensitive probes to search for WIMP dark matter interactions. The LZ collaboration is conducting R&D to study VUV light reflectivity from PTFE (Teflon) in LXe. Teflon is used in dual phase detectors both as an electrical insulator and as reflector of VUV scintillation light (~175 nm) to improve photon detection with photomultiplier tubes (PMTs). However, experimental data for the reflectance of VUV light from PTFE in LXe is not sufficiently conclusive. We present a new technique of measuring the light reflectivity from PTFE by varying the fractional area of the PMT in the detector. PTFE reflectivity measurements were performed as a function of Teflon wall thickness in the range of 2 mm to 9.5 mm. The method, apparatus and experimental results will be presented.

  2. Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches

    Energy Technology Data Exchange (ETDEWEB)

    Akerib, D.S.; et al.

    2017-02-08

    The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of $^{238}$U$_{e}$~$<$1.6~mBq/kg, $^{238}$U$_{l}$~$<$0.09~mBq/kg, $^{232}$Th$_{e}$~$=0.28\\pm 0.03$~mBq/kg, $^{232}$Th$_{l}$~$=0.25\\pm 0.02$~mBq/kg, $^{40}$K~$<$0.54~mBq/kg, and $^{60}$Co~$<$0.02~mBq/kg (68\\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of $0.160\\pm0.001$(stat)$\\pm0.030$(sys) counts.

  3. Low radioactivity argon dark matter search results from the DarkSide-50 experiment

    CERN Document Server

    Agnes, P; Albuquerque, I F M; Alexander, T; Alton, A K; Arisaka, K; Back, H O; Baldin, B; Biery, K; Bonfini, G; Bossa, M; Bottino, B; Brigatti, A; Brodsky, J; Budano, F; Bussino, S; Cadeddu, M; Cadonati, L; Cadoni, M; Calaprice, F; Canci, N; Candela, A; Cao, H; Cariello, M; Carlini, M; Catalanotti, S; Cavalcante, P; Chepurnov, A; Cocco, A G; Covone, G; Crippa, L; D'Angelo, D; D'Incecco, M; Davini, S; De Cecco, S; De Deo, M; De Vincenzi, M; Derbin, A; Devoto, 25 A; Di Eusanio, F; Di Pietro, G; Edkins, E; Empl, A; Fan, A; Fiorillo, G; Fomenko, K; Forster, G; Franco, D; Gabriele, F; Galbiati, C; Giganti, C; Goretti, A M; Granato, F; Grandi, L; Gromov, M; Guan, M; Guardincerri, Y; Hackett, B R; Herner, K; Hungerford, E V; Ianni, Al; Ianni, An; James, I; Jollet, C; Keeter, K; Kendziora, C L; Kobychev, V; Koh, G; Korablev, D; Korga, G; Kubankin, A; Li, X; Lissia, M; Lombardi, P; Luitz, S; Ma, Y; Machulin, I N; Mandarano, A; Mari, S M; Maricic, J; Marini, L; Martoff, C J; Meregaglia, A; Meyers, P D; Miletic, T; Milincic, R; Montanari, D; Monte, A; Montuschi, M; Monzani, M; Mosteiro, P; Mount, B J; Muratova, V N; Musico, P; Napolitano, J; Nelson, A; Odrowski, S; Orsini, M; Ortica, F; Pagani, L; Pallavicini, M; Pantic, E; Parmeggiano, S; Pelczar, K; Pelliccia, N; Perasso, S; Pocar, A; Pordes, S; Pugachev, D A; Qian, H; Randle, K; Ranucci, G; Razeto, A; Reinhold, B; Renshaw, A L; Romani, A; Rossi, B; Rossi, N; Rountree, D; Sablone, D; Saggese, P; Saldanha, R; Sands, W; Sangiorgio, S; Savarese, C; Segreto, E; Semenov, D A; Shields, E; Singh, P N; Skorokhvatov, M D; Smallcomb, M; Smirnov, O; Sotnikov, A; Stanford, C; Suvorov, Y; Tartaglia, R; Tatarowicz, J; Testera, G; Tonazzo, A; Trinchese, P; Unzhakov, E V; Vishneva, A; Vogelaar, B; Wada, M; Walker, S; Wang, H; Wang, Y; Watson, A W; Westerdale, S; Wilhelmi, J; Wojcik, M M; Xiang, X; Xu, J; Yang, C; Yoo, J; Zavatarelli, S; Zec, A; Zhong, W; Zhu, C; Zuzel, G

    2015-01-01

    The DarkSide-50 dark matter search reports the first results obtained using a target of low-radioactivity argon extracted from underground sources. The experiment is located at the Laboratori Nazionali del Gran Sasso and uses a two-phase time projection chamber as a detector. A total of 155 kg of low radioactivity argon has been obtained, and we have determined that underground argon is depleted in Ar-39 by a factor (1.4 +- 0.2) x 10^3 relative to atmospheric argon. The underground argon was also found to contain (2.05 +- 0.13) mBq/kg of Kr-85. We found no evidence for dark matter in the form of WIMPs in 70.9 live-days of data with a fiducial mass of (36.9 +- 0.6) kg. When combined with our preceding search with an atmospheric argon target, we set a 90 % C.L. upper limit on the WIMP-nucleon spin-independent cross section of 2.0 x 10^-44 cm^2 (8.6 x 10^-44 cm^2, 8.0 x 10^-43 cm^2 ) for a WIMP mass of 100 GeV/c^2 (1 TeV/c^2 , 10 TeV/c^2 ).

  4. First dark matter search results from the PandaX-I experiment

    Science.gov (United States)

    Xiao, MengJiao; Xiao, Xiang; Zhao, Li; Cao, XiGuang; Chen, Xun; Chen, YunHua; Cui, XiangYi; Fang, DeQing; Fu, ChangBo; Giboni, Karl L.; Gong, HaoWei; Guo, GuoDong; Hu, Jie; Huang, XingTao; Ji, XiangDong; Ju, YongLin; Lei, SiAo; Li, ShaoLi; Lin, Qing; Liu, HuaXuan; Liu, JiangLai; Liu, Xiang; Lorenzon, Wolfgang; Ma, YuGang; Mao, YaJun; Ni, KaiXuan; Pushkin, Kirill; Ren, XiangXiang; Schubnell, Michael; Shen, ManBing; Stephenson, Scott; Tan, AnDi; Tarlé, Greg; Wang, HongWei; Wang, JiMin; Wang, Meng; Wang, XuMing; Wang, Zhou; Wei, YueHuan; Wu, ShiYong; Xie, PengWei; You, YingHui; Zeng, XiongHui; Zhang, Hua; Zhang, Tao; Zhu, ZhongHua

    2014-11-01

    We report on the first dark-matter (DM) search results from PandaX-I, a low threshold dual-phase xenon experiment operating at the China JinPing Underground Laboratory. In the 37-kg liquid xenon target with 17.4 live-days of exposure, no DM particle candidate event was found. This result sets a stringent limit for low-mass DM particles and disfavors the interpretation of previously-reported positive experimental results. The minimum upper limit, 3.7 × 10-44 cm2, for the spin-independent isoscalar DM-particle-nucleon scattering cross section is obtained at a DM-particle mass of 49GeV/c2 at 90% confidence level.

  5. First dark matter search results from the PandaX-I experiment

    CERN Document Server

    Xiao, Mengjiao; Zhao, Li; Cao, Xiguang; Chen, Xun; Chen, Yunhua; Cui, Xiangyi; Fang, Deqing; Fu, Changbo; Giboni, Karl L; Gong, Haowei; Guo, Guodong; Hu, Jie; Huang, Xingtao; Ji, Xiangdong; Ju, Yonglin; Lei, Siao; Li, Shaoli; Lin, Qing; Liu, Huaxuan; Liu, Jianglai; Liu, Xiang; Lorenzon, Wolfgang; Ma, Yugang; Mao, Yajun; Ni, Kaixuan; Pushkin, Kirill; Ren, Xiangxiang; Schubnell, Michael; Shen, Manbing; Stephenson, Scott; Tan, Andi; Tarle, Greg; Wang, Hongwei; Wang, Jimin; Wang, Meng; Wang, Xuming; Wang, Zhou; Wei, Yuehuan; Wu, Shiyong; Xie, Pengwei; You, Yinghui; Zeng, Xionghui; Zhang, Hua; Zhang, Tao; Zhu, Zhonghua

    2014-01-01

    We report on the first dark-matter (DM) search results from PandaX-I, a low threshold dual-phase xenon experiment operating at the China Jinping Underground Laboratory. In the 37-kg liquid xenon target with 17.4 live-days of exposure, no DM particle candidate event was found. This result sets a stringent limit for low-mass DM particles and disfavors the interpretation of previously-reported positive experimental results. The minimum upper limit, $3.7\\times10^{-44}$\\,cm$^2$, for the spin-independent isoscalar DM-particle-nucleon scattering cross section is obtained at a DM-particle mass of 49\\,GeV/c$^2$ at 90\\% confidence level.

  6. Low-mass dark matter search results from full exposure of PandaX-I experiment

    CERN Document Server

    Xiao, Xiang; Tan, Andy; Chen, Yunhua; Cui, Xiangyi; Fang, Deqing; Fu, Changbo; Giboni, Karl L; Gong, Haowei; Guo, Guodong; He, Ming; Ji, Xiangdong; Ju, Yonglin; Lei, Siao; Li, Shaoli; Lin, Qing; Liu, Huaxuan; Liu, Jianglai; Liu, Xiang; Lorenzon, Wolfgang; Ma, Yugang; Mao, Yajun; Ni, Kaixuan; Pushkin, Kirill; Ren, Xiangxiang; Schubnell, Michael; Shen, Manbing; Shi, Yuji; Stephenson, Scott; Wang, Hongwei; Wang, Jiming; Wang, Meng; Wang, Siguang; Wang, Xuming; Wang, Zhou; Wu, Shiyong; Xiao, Mengjiao; Xie, Pengwei; Yan, Binbin; You, Yinghui; Zeng, Xionghui; Zhang, Tao; Zhao, Li; Zhou, Xiaopeng; Zhu, Zhonghua

    2015-01-01

    We report the results of a weakly-interacting massive particle (WIMP) dark matter search using the full 80.1\\;live-day exposure of the first stage of the PandaX experiment (PandaX-I) located in the China Jin-Ping Underground Laboratory. The PandaX-I detector has been optimized for detecting low-mass WIMPs, achieving a photon detection efficiency of 9.6\\%. With a fiducial liquid xenon target mass of 54.0\\,kg, no significant excess event were found above the expected background. A profile likelihood analysis confirms our earlier finding that the PandaX-I data disfavor all positive low-mass WIMP signals reported in the literature under standard assumptions. A stringent bound on the low mass WIMP is set at WIMP mass below 10\\,GeV/c$^2$, demonstrating that liquid xenon detectors can be competitive for low-mass WIMP searches.

  7. First dark matter search results from the PandaX-I experiment

    Institute of Scientific and Technical Information of China (English)

    XIAO MengJiao; XIAO Xiang; ZHAO Li; CAO XiGuang; CHEN Xun; CHEN YunHua; CUI XiangYi

    2014-01-01

    We report on the first dark-matter (DM) search results from PandaX-Ⅰ,a low threshold dual-phase xenon experiment operating at the China JinPing Underground Laboratory.In the 37-kg liquid xenon target with 17.4 live-days of exposure,no DM particle candidate event was found.This result sets a stringent limit for low-mass DM particles and disfavors the interpretation of previously-reported positive experimental results.The minimum upper limit,3.7 × 10-44 cm2,for the spin-independent isoscalar DM-particle-nucleon scattering cross section is obtained at a DM-particle mass of 49 GeV/c2 at 90% confidence level.

  8. Gender matters: Experiences and consequences of digital dating abuse victimization in adolescent dating relationships.

    Science.gov (United States)

    Reed, Lauren A; Tolman, Richard M; Ward, L Monique

    2017-08-01

    Digital dating abuse (DDA) behaviors include the use of digital media to monitor, control, threaten, harass, pressure, or coerce a dating partner. In this study, 703 high school students reported on the frequency of DDA victimization, whether they were upset by these incidents, and how they responded. Results suggest that although both girls and boys experienced DDA at similar rates of frequency (with the exception of sexual coercion), girls reported that they were more upset by these behaviors. Girls also expressed more negative emotional responses to DDA victimization than boys. Although DDA is potentially harmful for all youth, gender matters. These findings suggest that the experience and consequences of DDA may be particularly detrimental for girls. Copyright © 2017 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  9. First Results from Dark Matter Search Experiment in the Nokogiriyama Underground Cell

    CERN Document Server

    Ootani, W; Miuchi, K; Inoue, Y; Watanabe, T; Yoshida, M; Ito, Y; Ootuka, Y

    1999-01-01

    An experiment to search for hypothetical particle dark matter using cryogenic thermal detector, or bolometer is ongoing. The bolometer consists of eight pieces of 21 g LiF absorbers and sensitive NTD germanium thermistors attached to them and is installed in the Nokogiriyama underground cell which is a shallow depth site ($\\sim 15$ m w.e.). We report on the results from the first running for about ten days using this arrayed bolometer system together with appropriate shieldings and muon veto counters. From the obtained energy spectra the exclusion limits for the cross section of the elastic neutralino-proton scattering are derived under commonly accepted astrophysical assumptions. The sensitivity for the light neutralino with a mass below 5 GeV is improved by this work.

  10. Long-term lysimeter experiment to analyze the influence of the climate change on matter fluxes

    Science.gov (United States)

    Pütz, Thomas; Groh, Jannis; Wollschläger, Ute; Gerke, Horst; Priesack, Eckart; Kiese, Ralf; Borg, Erik; Vereecken, Harry

    2015-04-01

    Based on the TERENO SoilCan infrastructure, a long-term large-scale experiment was designed to study the effects of climate change on terrestrial systems. The water and matter fluxes in soil are the main focuses of SoilCan. In the frame of SoilCan, fully automated lysimeter systems were installed on several highly equipped experimental field sites of the TERENO-observatories and the relevant status variables of each ecosystem were monitored (e.g. climate, hydrology, biosphere-atmosphere exchange, biodiversity, etc.). In total, 90 lysimeters (1.5 m depth, 1m2 surface) were filled with soil monoliths at the four TERENO-observatories and were instrumented with TDRs, tensiometers, temperature sensors, soil heat flux plates, and CO2 sensors. For the controlling of the lower boundary condition, suction candle rakes were installed into the lysimeter bottoms. In combination with bi-directional pumps and tanks, the water content of the lysimeters was adjusted to the surrounded original field sites. To simulate the expected climate change, 48 lysimeters were transferred along temperature and rainfall gradients within the respective observatories and between the observatories, based on the principle 'Space for Time'. In case of the "Rur" observatory, three intensively instrumented field sites ("Wüstebach", "Rollesbroich" und "Selhausen") were equipped with lysimeter stations. These three field sites include different land uses, "Wüstebach" as a forest site, "Rollesbroich" as a grassland and "Selhausen" as an arable site. In order to standardize the agronomic management, the crop rotation at the arable lysimeters comprised winter wheat - winter rye - winter barley - oats. For investigation of the matter flux, soil solutions and leachates were regularly sampled. The water balances and the dynamics of the carbon and nitrogen fluxes in the first two years of the experiment will be presented.

  11. Hydrogen dynamics in soil organic matter as determined by 13C and 2H labeling experiments

    Science.gov (United States)

    Paul, Alexia; Hatté, Christine; Pastor, Lucie; Thiry, Yves; Siclet, Françoise; Balesdent, Jérôme

    2016-12-01

    Understanding hydrogen dynamics in soil organic matter is important to predict the fate of 3H in terrestrial environments. One way to determine hydrogen fate and to point out processes is to examine the isotopic signature of the element in soil. However, the non-exchangeable hydrogen isotopic signal in soil is complex and depends on the fate of organic compounds and microbial biosyntheses that incorporate water-derived hydrogen. To decipher this complex system and to understand the close link between hydrogen and carbon cycles, we followed labeled hydrogen and labeled carbon throughout near-natural soil incubations. We performed incubation experiments with three labeling conditions: 1 - 13C2H double-labeled molecules in the presence of 1H2O; 2 - 13C-labeled molecules in the presence of 2H2O; 3 - no molecule addition in the presence of 2H2O. The preservation of substrate-derived hydrogen after 1 year of incubation (ca. 5 % in most cases) was lower than the preservation of substrate-derived carbon (30 % in average). We highlighted that 70 % of the C-H bonds are broken during the degradation of the molecule, which permits the exchange with water hydrogen. Added molecules are used more for trophic resources. The isotopic composition of the non-exchangeable hydrogen was mainly driven by the incorporation of water hydrogen during microbial biosynthesis. It is linearly correlated with the amount of carbon that is degraded in the soil. The quantitative incorporation of water hydrogen in bulk material and lipids demonstrates that non-exchangeable hydrogen exists in both organic and mineral-bound forms. The proportion of the latter depends on soil type and minerals. This experiment quantified the processes affecting the isotopic composition of non-exchangeable hydrogen, and the results can be used to predict the fate of tritium in the ecosystem or the water deuterium signature in organic matter.

  12. Academically Successful African American Male Urban High School Students' Experiences of Mattering to Others at School

    Science.gov (United States)

    Tucker, Catherine; Dixon, Andrea; Griddine, Ke'Shana

    2010-01-01

    Mattering to others has been shown to be a key construct of mental health and wellness. Emerging research links interpersonal mattering and school climate. In this study, the authors use transcendental phenomenology to explore how interpersonal mattering impacts the academic achievement of urban African American males who are academically…

  13. Simulations of radiation pressure experiments narrow down the energy and momentum of light in matter.

    Science.gov (United States)

    Bethune-Waddell, Max; Chau, Kenneth J

    2015-12-01

    Consensus on a single electrodynamic theory has yet to be reached. Discord was seeded over a century ago when Abraham and Minkowski proposed different forms of electromagnetic momentum density and has since expanded in scope with the gradual introduction of other forms of momentum and force densities. Although degenerate sets of electrodynamic postulates can be fashioned to comply with global energy and momentum conservation, hope remains to isolate a single theory based on detailed comparison between force density predictions and radiation pressure experiments. This comparison is two-fold challenging because there are just a handful of quantitative radiation pressure measurements over the past century and the solutions developed from different postulates, which consist of approximate expressions and inferential deductions, are scattered throughout the literature. For these reasons, it is appropriate to conduct a consolidated and comprehensive re-analysis of past experiments under the assumption that the momentum and energy of light in matter are degenerate. We create a combined electrodynamic/fluid dynamic simulation testbed that uses five historically significant sets of electrodynamic postulates, including those by Abraham and Minkowski, to model radiation pressure under diverse configurations with minimal assumptions. This leads to new interpretations of landmark investigations of light momentum, including the Balazs thought experiment, the Jones-Richards and Jones-Leslie measurements of radiation pressure on submerged mirrors, observations of laser-deformed fluid surfaces, and experiments on optical trapping and tractor beaming of dielectric particles. We discuss the merits and demerits of each set of postulates when compared to available experimental evidence and fundamental conservation laws. Of the five sets of postulates, the Abraham and Einstein-Laub postulates provide the greatest consistency with observations and the most physically plausible

  14. Search for WIMP dark matter in VBF- and monojet topologies with the ATLAS experiment at 13 TeV

    Energy Technology Data Exchange (ETDEWEB)

    Geisler, Manuel Patrice [Kirchhoff-Institut fuer Physik, Heidelberg (Germany)

    2016-07-01

    The cosmological evidence for Dark Matter is strong, however the nature of Dark Matter is still unknown and it has yet to be detected directly. The presented search with the ATLAS experiment at the LHC, CERN, focuses on WIMP (weakly interacting massive particles) Dark Matter candidates. Different kinds of final states are investigated: both so-called monojets and final states with at least two jets of high transverse momenta and a significant amount of missing transverse momentum. The inclusion of the two-jet selection criteria enhances the sensitivity of this search to vector boson fusion topologies. Furthermore, the selection criteria are optimized in order to suppress background processes that mimic the production of Dark Matter particles. In this talk, further techniques of the search are presented, and aspects of the analysis performed with the 2015 dataset of proton-proton collision at √(s)=13 TeV are covered.

  15. A Detailed Look at the First Results from the Large Underground Xenon (LUX) Dark Matter Experiment

    CERN Document Server

    Szydagis, M; Araujo, H M; Bai, X; Bailey, A J; Balajthy, J; Bernard, E; Bernstein, A; Bradley, A; Byram, D; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chapman, J J; Chiller, A A; Chiller, C; Coffey, T; Currie, A; de Viveiros, L; Dobi, A; Dobson, J; Druszkiewicz, E; Edwards, B; Faham, C H; Fiorucci, S; Flores, C; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C; Hertel, S A; Horn, M; Huang, D Q; Ihm, M; Jacobsen, R G; Kazkaz, K; Knoche, R; Larsen, N A; Lee, C; Lindote, A; Lopes, M I; Malling, D C; Mannino, R; McKinsey, D N; Mei, D -M; Mock, J; Moongweluwan, M; Morad, J; Murphy, A St J; Nehrkorn, C; Nelson, H; Neves, F; Ott, R A; Pangilinan, M; Parker, P D; Pease, E K; Pech, K; Phelps, P; Reichhart, L; Shutt, T; Silva, C; Solovov, V N; Sorensen, P; O'Sullivan, K; Taylor, D; Tennyson, B; Tiedt, D R; Tripathi, M; Uvarov, S; Verbus, J R; Walsh, N; Webb, R; White, J T; Witherell, M S; Wolfs, F L H; Woods, M; Zhang, C

    2014-01-01

    LUX, the world's largest dual-phase xenon time-projection chamber, with a fiducial target mass of 118 kg and 10,091 kg-days of exposure thus far, is currently the most sensitive direct dark matter search experiment. The initial null-result limit on the spin-independent WIMP-nucleon scattering cross-section was released in October 2013, with a primary scintillation threshold of 2 phe, roughly 3 keVnr for LUX. The detector has been deployed at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, and is the first experiment to achieve a limit on the WIMP cross-section lower than $10^{-45}$ cm$^{2}$. Here we present a more in-depth discussion of the novel energy scale employed to better understand the nuclear recoil light and charge yields, and of the calibration sources, including the new internal tritium source. We found the LUX data to be in conflict with low-mass WIMP signal interpretations of other results.

  16. An Experiment and Detection Scheme for Cavity-Based Light Cold Dark Matter Particle Searches

    Directory of Open Access Journals (Sweden)

    Masroor H. S. Bukhari

    2017-01-01

    Full Text Available A resonance detection scheme and some useful ideas for cavity-based searches of light cold dark matter particles (such as axions are presented, as an effort to aid in the on-going endeavors in this direction as well as for future experiments, especially in possibly developing a table-top experiment. The scheme is based on our idea of a resonant detector, incorporating an integrated tunnel diode (TD and GaAs HEMT/HFET (High-Electron Mobility Transistor/Heterogeneous FET transistor amplifier, weakly coupled to a cavity in a strong transverse magnetic field. The TD-amplifier combination is suggested as a sensitive and simple technique to facilitate resonance detection within the cavity while maintaining excellent noise performance, whereas our proposed Halbach magnet array could serve as a low-noise and permanent solution replacing the conventional electromagnets scheme. We present some preliminary test results which demonstrate resonance detection from simulated test signals in a small optimal axion mass range with superior signal-to-noise ratios (SNR. Our suggested design also contains an overview of a simpler on-resonance dc signal read-out scheme replacing the complicated heterodyne read-out. We believe that all these factors and our propositions could possibly improve or at least simplify the resonance detection and read-out in cavity-based DM particle detection searches (and other spectroscopy applications and reduce the complications (and associated costs, in addition to reducing the electromagnetic interference and background.

  17. Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab

    CERN Document Server

    Battaglieri, M; Caiffi, B; Celentano, A; De Vita, R; Fanchini, E; Marsicano, L; Musico, P; Osipenko, M; Panza, F; Ripani, M; Santopinto, E; Taiuti, M; Bellini, V; Bondí, M; De Napoli, M; Mammoliti, F; Leonora, E; Randazzo, N; Russo, G; Sperduto, M; Sutera, C; Tortorici, F; Baltzell, N; Dalton, M; Freyberger, A; Girod, F X; Kubarovsky, V; Pasyuk, E; Smith, E S; Stepanyan, S; Ungaro, M; Whitlatch, T; Izaguirre, E; Krnjaic, G; Snowden-Ifft, D; Loomba, D; Carpinelli, M; Sipala, V; Schuster, P; Toro, N; Essig, R; Wood, M H; Holtrop, M; Paremuzyan, R; De Cataldo, G; De Leo, R; Di Bari, D; Lagamba, L; Nappi, E; Perrino, R; Balossino, I; Barion, L; Ciullo, G; Contalbrigo, M; Lenisa, P; Movsisyan, A; Spizzo, F; Turisini, M; De Persio, F; Cisbani, E; Garibaldi, F; Meddi, F; Urciuoli, G M; Hasch, D; Lucherini, V; Mirazita, M; Pisano, S; Simi, G; D'Angelo, A; Lanza, L; Rizzo, A; Schaerf, C; Zonta, I; Filippi, A; Fegan, S; Kunkel, M; Bashkanov, M; Beltrame, P; Murphy, A; Smith, G; Watts, D; Zachariou, N; Zana, L; Glazier, D; Ireland, D; McKinnon, B; Sokhan, D; Colaneri, L; Pereira, S Anefalos; Afanasev, A; Briscoe, B; Strakovsky, I; Kalantarians, N; Weinstein, L; Adhikari, K P; Dunne, J A; Dutta, D; Fassi, L El; Ye, L; Hicks, K; Cole, P; Dobbs, S; Fanelli, C

    2016-01-01

    MeV-GeV dark matter (DM) is theoretically well motivated but remarkably unexplored. This proposal presents the MeV-GeV DM discovery potential for a $\\sim$1 m$^3$ segmented CsI(Tl) scintillator detector placed downstream of the Hall A beam-dump at Jefferson Lab, receiving up to 10$^{22}$ electrons-on-target (EOT) in 285 days. This experiment (Beam-Dump eXperiment or BDX) would be sensitive to elastic DM-electron and to inelastic DM scattering at the level of 10 counts per year, reaching the limit of the neutrino irreducible background. The distinct signature of a DM interaction will be an electromagnetic shower of few hundreds of MeV, together with a reduced activity in the surrounding active veto counters. A detailed description of the DM particle $\\chi$ production in the dump and subsequent interaction in the detector has been performed by means of Monte Carlo simulations. Different approaches have been used to evaluate the expected backgrounds: the cosmogenic background has been extrapolated from the result...

  18. Dance Experience and Associations with Cortical Gray Matter Thickness in the Aging Population

    Directory of Open Access Journals (Sweden)

    Shai Porat

    2016-10-01

    Full Text Available Introduction: We investigated the effect dance experience may have on cortical gray matter thickness and cognitive performance in elderly participants with and without mild cognitive impairment (MCI. Methods: 39 cognitively normal and 48 MCI elderly participants completed a questionnaire regarding their lifetime experience with music, dance, and song. Participants identified themselves as either dancers or nondancers. All participants received structural 1.5-tesla MRI scans and detailed clinical and neuropsychological evaluations. An advanced 3D cortical mapping technique was then applied to calculate cortical thickness. Results: Despite having a trend-level significantly thinner cortex, dancers performed better in cognitive tasks involving learning and memory, such as the California Verbal Learning Test-II (CVLT-II short delay free recall (p = 0.004, the CVLT-II long delay free recall (p = 0.003, and the CVLT-II learning over trials 1-5 (p = 0.001. Discussion: Together, these results suggest that dance may result in an enhancement of cognitive reserve in aging, which may help avert or delay MCI.

  19. Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab

    CERN Document Server

    Battaglieri, M; De Vita, R; Izaguirre, E; Krnjaic, G; Smith, E; Stepanyan, S; Bersani, A; Fanchini, E; Fegan, S; Musico, P; Osipenko, M; Ripani, M; Santopinto, E; Taiuti, M; Schuster, P; Toro, N; Dalton, M; Freyberger, A; Girod, F -X; Kubarovsky, V; Ungaro, M; De Cataldo, G; De Leo, R; Di Bari, D; Lagamba, L; Nappi, E; Perrino, R; Carpinelli, M; Sipala, V; Aiello, S; Bellini, V; De Napoli, M; Giusa, A; Mammoliti, F; Leonora, E; Noto, F; Randazzo, N; Russo, G; Sperduto, M; Sutera, C; Ventura, C; Barion, L; Ciullo, G; Contalbrigo, M; Lenisa, P; Movsisyan, A; Spizzo, F; Turisini, M; De Persio, F; Cisbani, E; Fanelli, C; Garibaldi, F; Meddi, F; Urciuoli, G M; Pereira, S Anefalos; De Sanctis, E; Hasch, D; Lucherini, V; Mirazita, M; Montgomery, R; Pisano, S; Simi, G; D'Angelo, A; Lanza, L Colaneri L; Rizzo, A; Schaerf, C; Zonta, I; Calvo, D; Filippi, A; Holtrop, M; Peremuzyan, R; Glazier, D; Ireland, D; McKinnon, B; Afanasev, D Sokhan A; Briscoe, B; Kalantarians, N; Fassi, L El; Weinstein, L; Beltrame, P; Murphy, A; Watts, D; Zana, L; Hicks, K

    2014-01-01

    MeV-GeV dark matter (DM) is theoretically well motivated but remarkably unexplored. This Letter of Intent presents the MeV-GeV DM discovery potential for a 1 m$^3$ segmented plastic scintillator detector placed downstream of the beam-dump at one of the high intensity JLab experimental Halls, receiving up to 10$^{22}$ electrons-on-target (EOT) in a one-year period. This experiment (Beam-Dump eXperiment or BDX) is sensitive to DM-nucleon elastic scattering at the level of a thousand counts per year, with very low threshold recoil energies ($\\sim$1 MeV), and limited only by reducible cosmogenic backgrounds. Sensitivity to DM-electron elastic scattering and/or inelastic DM would be below 10 counts per year after requiring all electromagnetic showers in the detector to exceed a few-hundred MeV, which dramatically reduces or altogether eliminates all backgrounds. Detailed Monte Carlo simulations are in progress to finalize the detector design and experimental set up. An existing 0.036 m$^3$ prototype based on the s...

  20. Dance Experience and Associations with Cortical Gray Matter Thickness in the Aging Population.

    Science.gov (United States)

    Porat, Shai; Goukasian, Naira; Hwang, Kristy S; Zanto, Theodore; Do, Triet; Pierce, Jonathan; Joshi, Shantanu; Woo, Ellen; Apostolova, Liana G

    2016-01-01

    We investigated the effect dance experience may have on cortical gray matter thickness and cognitive performance in elderly participants with and without mild cognitive impairment (MCI). 39 cognitively normal and 48 MCI elderly participants completed a questionnaire regarding their lifetime experience with music, dance, and song. Participants identified themselves as either dancers or nondancers. All participants received structural 1.5-tesla MRI scans and detailed clinical and neuropsychological evaluations. An advanced 3D cortical mapping technique was then applied to calculate cortical thickness. Despite having a trend-level significantly thinner cortex, dancers performed better in cognitive tasks involving learning and memory, such as the California Verbal Learning Test-II (CVLT-II) short delay free recall (p = 0.004), the CVLT-II long delay free recall (p = 0.003), and the CVLT-II learning over trials 1-5 (p = 0.001). Together, these results suggest that dance may result in an enhancement of cognitive reserve in aging, which may help avert or delay MCI.

  1. The evolution of future geogenic matter fluxes due Enhanced Weathering: Results from the Antwerp Experiment

    Science.gov (United States)

    Hartmann, Jens; Weiss, Andreas; Struyf, Eric; Schoelynck, Jonas; Meire, Patrick; Amann, Thorben

    2015-04-01

    Understanding the evolution of geogenic matter fluxes in soils due the application of rock products ontop of soils is relevant to evaluate alteration of soil solutions and saturation states of solutes. In the future the practice of applying rock products will continue and areas affected will likely spread (Hartmann et al., 2013). This trend will likely be fuelled by attempts to optimize carbon dioxide removal by increasing biomass production, soil organic carbon stocks, increase crop production or afforestation. All those efforts demand a certain amount of geogenic nutrients, which need to be replaced. To investigate the release patterns and the downward transport of an array of elements, and to study their fate as well as reaction processes, altered through this practice, a mesocosm experiment was established at Antwerp University. Extended results will be presented (c.f., Weiss et al., 2014) focusing on the release and transport of DIC (dissolved inorganic carbon) and Mg (magnesium) in the soil column downwards after the application of 22 kg m-2 olivine powder. Elevated DIC and Mg concentrations are detected in case of olivine is applied to mesocosms with wheat and barley, if compared to the mesocsoms without plants, and without olivine. The change patterns in concentrations and fluxes will be discussed. Hartmann, J., et al. (2013) Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification. Reviews of Geophysics; 51(2), 113-149. doi: 10.1002/rog.20004 Weiss, A., et al. (2014) The overlooked compartment of the critical-zone-complex, considering the evolution of future geogenic matter fluxes: Agricultural topsoils. Procedia Earth and Planetary Science, 10, 339-342. doi:10.1016/j.proeps.2014.08.032

  2. Warm, Dense Plasma Characterization by X-ray Thomson Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Landen, O L; Glenzer, S H; Cauble, R C; Lee, R W; Edwards, J E; Degroot, J S

    2000-07-18

    We describe how the powerful technique of spectrally resolved Thomson scattering can be extended to the x-ray regime, for direct measurements of the ionization state, density, temperature, and the microscopic behavior of dense cool plasmas. Such a direct measurement of microscopic parameters of solid density plasmas could eventually be used to properly interpret laboratory measurements of material properties such as thermal and electrical conductivity, EUS and opacity. In addition, x-ray Thomson scattering will provide new information on the characteristics of rarely and hitherto difficult to diagnose Fermi degenerate and strongly coupled plasmas.

  3. 直接探测暗物质和中国暗物质实验%Dark matter direct detection and China dark matter experiment

    Institute of Scientific and Technical Information of China (English)

    刘书魁; 岳骞

    2015-01-01

    暗物质探测已成为当今科学最重要的课题之一.弱相互作用重粒子(weakly interacting massive particles, WIMPs)是众多理论模型中最有可能的暗物质候选者之一.暗物质直接探测原理是:WIMPs与地面探测器的靶核通过弱相互作用,发生弹性散射,反冲核被弹出,探测器将反冲核能量记录下来,得到暗物质与探测器相互作用的信号.文章介绍了国际上主流的暗物质直接探测的方法、现状以及未来直接探测的路线.还介绍了世界最深地下实验室——中国锦屏地下实验室的现状和二期扩建情况.文章最后详细介绍了中国暗物质合作组的研究历程、探测技术、研究取得的成果和未来规划.%The nature of dark matter in our universe is one of the most challenging prob-lems in science today. A most probable class of dark matter is the weakly interacting massive parti-cles (WIMPs), which exhibit a wide range of features. Current experiments searching for dark matter aim for direct detection via the elastic scattering off ordinary matter in terrestrial detectors. This paper will present the main methods, status and roadmap for the direct detection of dark mat-ter. The world's deepest laboratory, China Jinping underground laboratory and its extension, will also be described. Finally, we will give a detailed introduction to the research history, detection technologies, current results, and future prospects of China dark matter experiment (CDEX).

  4. Uncoupling of bacterial and terrigenous dissolved organic matter dynamics in decomposition experiments.

    Directory of Open Access Journals (Sweden)

    Daniel P R Herlemann

    Full Text Available The biodegradability of terrigenous dissolved organic matter (tDOM exported to the sea has a major impact on the global carbon cycle, but our understanding of tDOM bioavailability is fragmentary. In this study, the effects of preparative tDOM isolation on microbial decomposition were investigated in incubation experiments consisting of mesocosms containing mesohaline water from the Baltic Sea. Dissolved organic carbon (DOC consumption, molecular DOM composition, bacterial activities, and shifts in bacterial community structure were compared between mesocosms supplemented with riverine tDOM, either as filtered, particle-free river water or as a concentrate obtained by lyophilization/tangential ultrafiltration, and those containing only Baltic Sea water or river water. As shown using ultra-high-resolution mass spectrometry (15 Tesla Fourier-transform ion cyclotron resonance mass spectrometry, FT-ICR-MS covering approximately 4600 different DOM compounds, the three DOM preparation protocols resulted in distinct patterns of molecular DOM composition. However, despite DOC losses of 4-16% and considerable bacterial production, there was no significant change in DOM composition during the 28-day experiment. Moreover, tDOM addition affected neither DOC degradation nor bacterial dynamics significantly, regardless of the tDOM preparation. This result suggested that the introduced tDOM was largely not bioavailable, at least on the temporal scale of our experiment, and that the observed bacterial activity and DOC decomposition mainly reflected the degradation of unknown, labile, colloidal and low-molecular weight DOM, both of which escape the analytical window of FT-ICR-MS. In contrast to the different tDOM preparations, the initial bacterial inoculum and batch culture conditions determined bacterial community succession and superseded the effects of tDOM addition. The uncoupling of tDOM and bacterial dynamics suggests that mesohaline bacterial communities

  5. Effects of Conceptual Change Texts and Laboratory Experiments on Fourth Grade Students' Understanding of Matter and Change Concepts

    Science.gov (United States)

    Durmus, Jale; Bayraktar, Sule

    2010-01-01

    The purpose of this study was to investigate whether conceptual change texts and laboratory experiments are effective in overcoming misconceptions and whether the concepts were acquired permanently when these methods were utilized. In this study, we addressed some topics from the "Matter and Change" unit in science and technology class of…

  6. Technical Results from the Surface Run of the LUX Dark Matter Experiment

    CERN Document Server

    Akerib, D S; Bernard, E; Bernstein, A; Bradley, A; Byram, D; Cahn, S B; Carmona-Benitez, M C; Chapman, J J; Coffey, T; Dobi, A; Dragowsky, E; Druszkiewicz, E; Edwards, B; Faham, C H; Fiorucci, S; Gaitskell, R J; Gibson, K R; Gilchriese, M; Hall, C; Hanhardt, M; Ihm, M; Jacobsen, R G; Kastens, L; Kazkaz, K; Knoche, R; Larsen, N; Lee, C; Lesko, K T; Lindote, A; Lopes, M I; Lyashenko, A; Malling, D C; Mannino, R; McKinsey, D N; Mei, D; Mock, J; Moongweluwan, M; Morii, M; Nelson, H; Neves, F; Nikkel, J A; Pangilinan, M; Pech, K; Phelps, P; Rodionov, A; Shutt, T; Silva, C; Skulski, W; Solovov, V N; Sorensen, P; Stiegler, T; Sweany, M; Szydagis, M; Taylor, D; Tripathi, M; Uvarov, S; Verbus, J R; de Viveiros, L; Walsh, N; Webb, R; White, J T; Wlasenko, M; Wolfs, F L H; Woods, M; Zhang, C

    2012-01-01

    We present the results of the three-month above-ground commissioning run of the Large Underground Xenon (LUX) experiment at the Sanford Underground Research Facility located in Lead, South Dakota, USA. LUX is a 370 kg liquid xenon detector that will search for cold dark matter in the form of Weakly Interacting Massive Particles (WIMPs). The commissioning run, conducted with the detector immersed in a water tank, validated the integration of the various sub-systems in preparation of the underground deployment. Using the data collected, we report excellent light collection properties, achieving 8 photoelectrons per keV for 662 keV electron recoils without an applied electric field, measured in the center of the WIMP target. We also find good energy and position resolution in relatively high-energy interactions from a variety of internal and external sources. Finally, we have used the commissioning data to tune the optical properties of our simulation and report updated sensitivity projections for spin-independe...

  7. Progress in characterization of the Photomultiplier Tubes for XENON1T Dark Matter Experiment

    CERN Document Server

    Lyashenko, Alexey

    2015-01-01

    We report on the progress in characterization of the Hamamatsu model R11410-21 Photomultiplier tubes (PMTs) for XENON1T dark matter experiment. The absolute quantum efficiency (QE) of the PMT was measured at low temperatures down to -110 $^0$C (a typical the PMT operation temperature in liquid xenon detectors) in a spectral range from 154.5 nm to 400 nm. At -110 $^0$C the absolute QE increased by 10-15\\% at 175 nm compared to that measured at room temperature. A new low power consumption, low radioactivity voltage divider for the PMTs is being developed. The measurement results showed that the PMT with the current version of the divider demonstrated a linear response (within 5\\%) down to 5$\\cdot$10$^4$ photoelectrons at a rate of 200 Hz. The radioactive contamination induced by the PMT and the PMT voltage divider materials satisfies the requirements for XENON1T detector not to exceed a total radioactive contamination in the detector of 0.5 evts/year/1tonn. Most of the PMTs received from the manufacturer showe...

  8. Recovery and Reutilization of Waste Matter from Coffee Preparation. An Experiment for Environmental Science Courses

    Science.gov (United States)

    Orecchio, Santino

    2001-12-01

    This work is designed as an experience for organic and analytical chemistry laboratories in environmental science courses. Coffee grounds were chosen because they are easily available, they are a fine example of a waste product, and the students are familiar with them. The coffee bean is a source of a number of by-products. By comparing the physicochemical characteristics of coffee oil (from the grounds) with those of common oils, it is found that coffee oil shows similarity to palm oil. We hydrolysed the coffee oil and obtained a soap that had good detergent and foaming properties similar to olive oil soap or commercial products. Another beneficial aspect of the coffee bean results from the high content in organic matter (C = 48.9%) of the degreased coffee grounds, which allows their utilization to improve the fertility of soils. The total nitrogen content of the residue is higher than that of many composts and is similar to the nitrogen content of some commercial products employed for house plants. The economical, technical, and environmental advantages that frequently can derive from the recovery of some by-products of foods and beverages, such as the coffee grounds in this example, are evident.

  9. The cryogenic system for the Panda-X dark matter search experiment

    Science.gov (United States)

    Gong, H.; Giboni, K. L.; Ji, X.; Tan, A.; Zhao, L.

    2013-01-01

    Panda-X is a liquid xenon dual-phase detector for the Dark Matter Search. The first modestly-sized module will soon be installed in the China JinPing Deep Underground Laboratory in Sichuan province, P.R. China. The cryogenic system is designed to handle much larger detectors, even the final version in the ton scale. Special attention has been paid to the reliability, serviceability, and adaptability to the requirements of a growing experiment. The system is cooled by a single Iwatani PC150 Pulse Tube Refrigerator. After subtracting all thermal losses, the remaining cooling power is still 82 W. The fill speed was 0.75 g/s, but could be boosted by LN2 assisted cooling to 3.3 g/s. For the continuous recirculation and purification through a hot getter, a heat exchanger was employed to reduce the required cooling power. The recirculation speed is limited to 2.9 g/s by the gas pump. At this speed, recirculation only adds 18.5 W to the heat load of the system, corresponding to a 95.2 % efficiency of the heat exchanger.

  10. Searches for Dark Matter and Large Extra Dimensions in Monojet Final States with the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00286734

    This thesis presents searches for evidence for Weakly Interacting Massive Particles (WIMPs) and Extra Dimensions in proton-proton collisions recorded by the ATLAS experiment at the CERN Large Hadron Collider (LHC). The WIMP is one of the main candidates to constitute the particle content of Dark Matter. Extra Dimensions are introduced in several theories in order to explain the apparent weakness of gravity when compared to the other interactions in Nature. Theories with WIMPs as well as Extra Dimensions can manifest themselves at the LHC, with experimental signatures characterized by an energetic hadronic jet associated with large missing momentum. These signatures are known as monojet signatures, and are investigated in this thesis. The first analysis is performed using L = 20.3 fb$^{-1}$~of proton-proton collisions at $\\sqrt{s}$ = 8 TeV recorded in the ATLAS Run 1. The second analysis is performed using L = 3.2 fb$^{-1}$~of proton-proton collisions at $\\sqrt{s}$ = 13 TeV recorded in the ATLAS Run 2. No sign...

  11. A Comprehensive Study of Low-Energy Response for Xenon-Based Dark Matter Experiments

    CERN Document Server

    Wang, L

    2016-01-01

    We report a comprehensive study of the energy response to low-energy recoils in dual-phase xenon-based dark matter experiments. The average energy expended per electron-ion (e-ion) pair ($W_{i}$-value), quenching factors, and recombination involving energy response are extracted through the physics mechanisms behind each process. We derive the variation of the $W_{i}$-value using the exciton-to-ion ratio ($\\frac{N_{ex}}{N_{i}}$) as a function of recoil energy with the mean ionization potential. We show the scintillation quenching follows the form of Birks' law for electronic recoils at zero field. A recombination model is developed to explain the recombination probability as a function of recoil energy at zero field and non-zero field. The role of e-ion recombination is discussed for both parent recombination and volume recombination. We find that the volume recombination under non-zero field is constrained by a plasma effect, which is caused by a high density of charge carriers along the ionization track for...

  12. The Matter in Extreme Conditions (MEC) instrument at LCLS

    Science.gov (United States)

    Nagler, Bob

    2015-06-01

    The last five years have seen the commissioning of and first user experiments on both the Free Electron Laser in Hamburg (FLASH) and the Linac Coherent Light Source (LCLS) in Stanford, and more are slated to come online in the next couple of years . The high photon frequency (i.e. larger than the plasma frequency of solid density), short pulse length (i.e. 10s to 100s of femtoseconds) and large photon number per pulse (i.e. 1012 photons per pulse) make it an ideal source to create and study states of matter at high energy density, a long-standing scientific challenge. Indeed, while matter in extreme conditions, which for the purpose of this talk we define as states under pressure up to hundreds of GPa and with temperatures ranging between 1eV and 1000eV, has been studied through dynamic shock compression and there has been significant progress made over many decades. However, large uncertainties still exist in the atomic structure and crystallographic structure, existence of high pressure phases, scattering factors, and equation of state of matter in extreme conditions. The Matter in Extreme Condition (MEC) instrument at LCLS is designed to overcome the unique experimental challenges that the study of matter in extreme conditions bring. It combines a suite of diagnostics and high power and energy optical lasers, which are standard fare in this research field, with the unmatched LCLS X-ray beam, to create an instrument that will be at the forefront of, and have a major impact on MEC science, in particular in the field of high pressure, warm dense matter, high energy density, and ultra-high intensity laser-matter interaction studies. The LCLS beam allows for unique investigation in all these extreme states using diagnostic methods such as X-ray Thomson Scattering, X-ray emission spectroscopy, X-ray diffraction, X-ray absorption spectroscopy, X-ray phase-contrast imaging, and pumping specific absorption lines to study (dense) plasma kinetics. Augmented with optical

  13. CP violation and matter effect for a variable earth density in very long baseline experiments

    CERN Document Server

    Brahmachari, B; Roy, P; Brahmachari, Biswajoy; Choubey, Sandhya; Roy, Probir

    2003-01-01

    The perturbative treatment of subdominant oscillation and the matter effect in neutrino beams/superbeams, propagating over long baselines and being used to look for CP violation, is studied here for a general matter density function varying with distance. New lowest order analytic expressions are given for different flavour transition and survival probabilities in a general neutrino mixing basis and a variable earth matter density profile. It is demonstrated that the matter effect in the muon neutrino (antineutrino) flavour survival probability vanishes to this order, provided the depletion, observed for atmospheric muon neutrinos and antineutrinos at super-Kamiokande, is strictly maximal. This result is independent of the earth density profile and the distance L between the source and the detector. In the general variable density case we show that one cannot separate the matter induced asymmetry from a genuine CP effect by keeping two detectors at distances $L_1$ and $L_2$ from the source while maintaining a...

  14. Persistence of soil organic matter as an ecosystem property: implications for experiments, feedbacks, and modeling

    Science.gov (United States)

    Schmidt, M. W.; Torn, M. S.

    2012-12-01

    Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily—and this limits our ability to predict how soils will respond to land use or climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we summarize recent understanding and propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming. Numerical models of soil carbon cycling are used to attribute carbon sources and sinks, predict climate-ecosystem feedbacks, and evaluate biofuel and sequestration strategies. Current ecosystem models rest heavily on the concept of recalcitrance and most models partition plant input into pools of different turnover time solely on the basis of plant tissue chemistry. However, recent research enabled by isotopic, spectroscopic, and molecular marker tools finds little evidence that recalcitrance or selective preservation determine the long residence time of SOM. Without the assumption that recalcitrance or molecular structure control decomposition rates, the framework of these models is no longer justified. Some improvements can be made easily; in other areas, research is needed to translate recent findings into new parameters, for example, to predict the effect of organo-mineral interactions and soil depth on decomposition rates. In this presentation, we will describe a new view of soil carbon cycling that is consistent with the new generation of observations, discuss suggested improvements to soil carbon models, and explore the implications for the vulnerability of soil organic carbon.

  15. Prospects for detecting dark matter with neutrino telescopes in light of recent results from direct detection experiments

    Science.gov (United States)

    Halzen, Francis; Hooper, Dan

    2006-06-01

    Direct detection dark matter experiments, lead by the CDMS Collaboration, have placed increasingly stronger constraints on the cross sections for elastic scattering of weakly interacting massive particles (WIMPs) on nucleons. These results impact the prospects for the indirect detection of dark matter using neutrino telescopes. With this in mind, we revisit the prospects for detecting neutrinos produced by the annihilation of WIMPs in the Sun. We find that the latest bounds do not seriously limit the models most accessible to next generation kilometer-scale neutrino telescopes such as IceCube. This is largely due to the fact that models with significant spin-dependent couplings to protons are the least constrained and, at the same time, the most promising because of the efficient capture of WIMPs in the Sun. We identify models where dark matter particles are beyond the reach of any planned direct detection experiments while within reach of neutrino telescopes. In summary, we find that, even when contemplating recent direct detection results, neutrino telescopes still have the opportunity to play an important as well as complementary role in the search for particle dark matter.

  16. The Interplay Between Collider Searches For Supersymmetric Higgs Bosons and Direct Dark Matter Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Carena, Marcela; Hooper, Dan; /Fermilab; Vallinotto, Alberto; /Fermilab /Chicago U. /Paris, Inst. Astrophys.

    2006-11-01

    In this article, we explore the interplay between searches for supersymmetric particles and Higgs bosons at hadron colliders (the Tevatron and the LHC) and direct dark matter searches (such as CDMS, ZEPLIN, XENON, EDELWEISS, CRESST, WARP and others). We focus on collider searches for heavy MSSM Higgs bosons (A, H, H{sup {+-}}) and how the prospects for these searches are impacted by direct dark matter limits and vice versa. We find that the prospects of these two experimental programs are highly interrelated. A positive detection of A, H or H{sup {+-}} at the Tevatron would dramatically enhance the prospects for a near future direct discovery of neutralino dark matter. Similarly, a positive direct detection of neutralino dark matter would enhance the prospects of discovering heavy MSSM Higgs bosons at the Tevatron or the LHC. Combining the information obtained from both types of experimental searches will enable us to learn more about the nature of supersymmetry.

  17. Dark Matter Results from First 98.7-day Data of PandaX-II Experiment

    CERN Document Server

    Tan, Andi; Cui, Xiangyi; Chen, Xun; Chen, Yunhua; Fang, Deqing; Fu, Changbo; Giboni, Karl; Giuliani, Franco; Gong, Haowei; Hu, Shouyang; Huang, Xingtao; Ji, Xiangdong; Ju, Yonglin; Lei, Siao; Li, Shaoli; Li, Xiaomei; Li, Xinglong; Liang, Hao; Lin, Qing; Liu, Huaxuan; Liu, Jianglai; Lorenzon, Wolfgang; Ma, Yugang; Mao, Yajun; Ni, Kaixuan; Ren, Xiangxiang; Schubnell, Michael; Shen, Manbin; Shi, Fang; Wang, Hongwei; Wang, Jiming; Wang, Meng; Wang, Qiuhong; Wang, Siguang; Wang, Xuming; Wang, Zhou; Wu, Shiyong; Xiao, Xiang; Xie, Pengwei; Yan, Binbin; Yang, Yong; Yue, Jianfeng; Zeng, Xionghui; Zhang, Hongguang; Zhang, Hua; Zhang, Huanqiao; Zhang, Tao; Zhao, Li; Zhou, Jing; Zhou, Ning; Zhou, Xiaopeng

    2016-01-01

    We report the WIMP dark matter search results using the first physics-run data of the PandaX-II 500 kg liquid xenon dual-phase time-projection chamber, operating at the China JinPing Underground Laboratory. No dark matter candidate is identified above background. In combination with the data set during the commissioning run, with a total exposure of 3.3$\\times10^4$ kg-day,the most stringent limit to the spin-independent interaction between the ordinary and WIMP dark matter is set for a range of dark matter mass between 3.5 and 1000 GeV/c$^2$. The best upper limit on the scattering cross section is found $2.5\\times 10^{-46}$ cm$^2$ for the WIMP mass 40 GeV/c$^2$ at 90% confidence level.

  18. Fate of lignin, cutin and suberin in soil organic matter fractions - an incubation experiment

    Science.gov (United States)

    Mueller, Carsten W.; Mueller, Kevin E.; Freeman, Katherine H.; Ingrid, Kögel-Knabner

    2010-05-01

    The turnover of soil organic matter (SOM) is controlled by its chemical composition, its spatial accessibility and the association with the mineral phase. Separation of bulk soils by physical fractionation and subsequent chemical analysis of these fractions should give insights to how compositional differences in SOM drive turnover rates of different size-defined carbon pools. The main objective of this study was to elucidate the relative abundance and recalcitrance of lignin, cutin and suberin in aggregated bulk soils and SOM fractions in the course of SOM decomposition. Bulk soils and physically-separated size fractions (sand, silt and clay) of the Ah horizon of a forest soil (under Picea abies L.Karst) were parallel incubated over a period of one year. In order to differentiate between particulate OM (POM) and mineral-associated SOM the particle size fractions were additionally separated by density after the incubation experiment. We used solid-state 13C-CPMAS NMR spectroscopy and GC-MS (after copper oxide oxidation and solvent extraction) to analyze the composition of the incubated samples. The abundance and isotopic composition (including 13C and 14C) of the respired CO2 further enabled us to monitor the dynamics of SOM mineralization. This approach allowed for differentiating between C stabilization of soil fractions due to accessibility/aggregation and to biochemical recalcitrance at different scales of resolution (GC-MS, NMR). We found a relative enrichment of alkyl C and decreasing lignin contents in the order of sand < silt < clay by 13C-NMR spectroscopy and GC-MS within soils and fractions before the incubation, resulting in increased lipid to lignin ratios with decreasing particle size. An accumulation of aliphatic C compounds was especially found for the small silt and clay sized particulate OM (POM). For the fresh particulate OM (POM) of the sand fraction a clear decay of lignin was observed in the course of the incubation experiment, indicated by

  19. Dark Matter searches with Mono-X signatures at the ATLAS experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00377126; The ATLAS collaboration

    2016-01-01

    At the LHC dark matter particles can be produced in association with Standard Model particles coming from initial state radiation. Searches for such processes using events with jets, photons or massive gauge bosons recoiling against large missing transverse momentum in ATLAS at 13 TeV are presented. These ``mono-X'' signatures provide powerful probes to dark matter production at the LHC, allowing for the interpretation of results in terms of simplified models with pair production of WIMPs.

  20. Search for mirror dark matter in a laboratory experiment with ultracold neutrons

    CERN Document Server

    Serebrov, A P; Dovator, N A; Dmitriev, S P; Fomin, A K; Geltenbort, P; Kharitonov, A G; Krasnoschekova, I A; Lasakov, M S; Murashkin, A N; Shmelev, G E; Varlamov, V E; Vassiljev, A V; Zherebtsov, O M; Zimmer, O

    2008-01-01

    Mirror matter is considered as a candidate for dark matter. To investigate this possibility an experimental search for neutron - mirror neutron transitions has been carried out using storage of ultracold neutrons in a trap with different magnetic fields. As a result, a new limit for the neutron - mirror neutron oscillation time tau_osc has been obtained, tau_osc >= 448 s (90% C.L.). As a side result, some restriction of the presence of a mirror magnetic field in the range 0 - 1200 nT has been obtained.

  1. Optimization of a transition radiation detector for the compressed baryonic matter experiment

    Energy Technology Data Exchange (ETDEWEB)

    Arend, Andreas

    2014-07-01

    The Transition Radiation Detector (TRD) of the compressed baryonic matter (CBM) experiment at FAIR has to provide electron-pion separation as well as charged-particle tracking. Within this work, thin and symmetric Multi-Wire Proportional Chambers (MWPCs) without additional drift region were proposed. the proposed prototypes feature a foil-based entrance window to minimize the material budget and to reduce the absorption probability of the generated TR photon. Based on the conceptual design of thin and symmetric MWPCs without drift region, multiple prototypes were constructed and their performance presented within this thesis. With the constructed prototypes of generations II and III the geometries of the wire and cathode planes were determined to be 4+4 mm and 5+5 mm. Based on the results of a performed test beam campaign in 2011 with this prototypes new prototypes of generation IV were manufactured and tested in a subsequent test beam campaign in 2012. Prototypes of different radiators were developed together with the MWPC prototypes. Along with regular foil radiators, foam-based radiator types made of polyethylene foam were utilized. Also radiators constructed in a sandwich design, which used different fiber materials confined with solid foam sheets, were used. For the prototypes without drift region, simulations of the electrostatic and mechanical properties were performed. The GARFIELD software package was used to simulate the electric field and to determine the resulting drift lines of the generated electrons. The mean gas amplification depending on the utilized gas and the applied anode voltage was simulated and the gas-gain homogeneity was verified. Since the thin foil-based entrance window experiences a deformation due to pressure differences inside and outside the MWPC, the variation on the gas gain depending on the deformation was simulated. The mechanical properties focusing on the stability of the entrance window was determined with a finiteelement

  2. Challenging "Size Matters" Messages: An Exploration of the Experiences of Critical Obesity Scholars in Higher Education

    Science.gov (United States)

    Cameron, Erin

    2016-01-01

    Given that postsecondary institutions are increasingly seen as sites to promote health, critical scholars are calling attention to how the contemporary Western weight-centred health paradigm reinforces a "size matters" message that is fueling harmful attitudes towards and judgments of bodies. As such, research that highlights strategies…

  3. Operating the GridPix detector in dark matter search experiments

    NARCIS (Netherlands)

    Schön, R.; Alfonsi, M.; Hemink, G.; Decowski, M.P.; van Bakel, N.; van der Graaf, H.

    2013-01-01

    The DARWIN (dark matter WIMP search with noble liquids) design study aims to use liquid argon and liquid xenon targets to look for nuclear recoils due to weakly interacting massive particles (WIMPs). To measure the recoil energy in dual-phase noble gas time projection chambers the combination of sci

  4. Production of low-background CuSn6-bronze for the CRESST dark-matter-search experiment.

    Science.gov (United States)

    Majorovits, B; Kader, H; Kraus, H; Lossin, A; Pantic, E; Petricca, F; Proebst, F; Seidel, W

    2009-01-01

    One of the most intriguing open questions in modern particle physics is the nature of the dark matter in our universe. As hypothetical weakly interacting massive particles (WIMPs) do interact with ordinary matter extremely rarely, their observation requires a very low-background detector environment regarding radioactivity as well as an advanced detector technique that allows for active discrimination of the still present radioactive contaminations. The CRESST experiment uses detectors operating at milli-Kelvin temperature. Energy deposition in the detectors is recorded via the simultaneous measurement of a phonon-mediated signal and scintillation emitted by the CaWO(4) crystal targets. The entire setup is made of carefully selected materials. In this note we report on the development of ultra-pure bronze (CuSn(6)) wire in small quantities for springs and clamps that are currently being used in the CRESST II setup.

  5. Matter-enhanced CP violation and Dirac unitarity triangles in a low-energy medium-baseline neutrino oscillation experiment

    CERN Document Server

    Xing, Zhi-zhong

    2016-01-01

    The strength of CP violation in an accelerator-based neutrino oscillation experiment is characterized by the matter-corrected parameter \\widetilde{\\cal J}, a counterpart of the fundamental Jarlskog invariant \\cal J. We find a unique range of the neutrino beam energy, E \\lesssim 0.3 GeV, in which the size of \\widetilde{\\cal J} can be amplified as compared with that of {\\cal J}. The ratio \\widetilde{\\cal J}/{\\cal J} peaks at the resonance energy E_* \\simeq 0.14 GeV (or 0.12 GeV) for the normal (or inverted) neutrino mass hierarchy. In the complex plane we show how the three Dirac unitarity triangles of lepton flavor mixing are deformed due to the matter corrections. The probabilities of \

  6. Overestimation of Crop Root Biomass in Field Experiments Due to Extraneous Organic Matter

    Science.gov (United States)

    Hirte, Juliane; Leifeld, Jens; Abiven, Samuel; Oberholzer, Hans-Rudolf; Hammelehle, Andreas; Mayer, Jochen

    2017-01-01

    Root biomass is one of the most relevant root parameters for studies of plant response to environmental change, soil carbon modeling or estimations of soil carbon sequestration. A major source of error in root biomass quantification of agricultural crops in the field is the presence of extraneous organic matter in soil: dead roots from previous crops, weed roots, incorporated above ground plant residues and organic soil amendments, or remnants of soil fauna. Using the isotopic difference between recent maize root biomass and predominantly C3-derived extraneous organic matter, we determined the proportions of maize root biomass carbon of total carbon in root samples from the Swiss long-term field trial “DOK.” We additionally evaluated the effects of agricultural management (bio-organic and conventional), sampling depth (0–0.25, 0.25–0.5, 0.5–0.75 m) and position (within and between maize rows), and root size class (coarse and fine roots) as defined by sieve mesh size (2 and 0.5 mm) on those proportions, and quantified the success rate of manual exclusion of extraneous organic matter from root samples. Only 60% of the root mass that we retrieved from field soil cores was actual maize root biomass from the current season. While the proportions of maize root biomass carbon were not affected by agricultural management, they increased consistently with soil depth, were higher within than between maize rows, and were higher in coarse (>2 mm) than in fine (≤2 and >0.5) root samples. The success rate of manual exclusion of extraneous organic matter from root samples was related to agricultural management and, at best, about 60%. We assume that the composition of extraneous organic matter is strongly influenced by agricultural management and soil depth and governs the effect size of the investigated factors. Extraneous organic matter may result in severe overestimation of recovered root biomass and has, therefore, large implications for soil carbon modeling and

  7. Overestimation of Crop Root Biomass in Field Experiments Due to Extraneous Organic Matter.

    Science.gov (United States)

    Hirte, Juliane; Leifeld, Jens; Abiven, Samuel; Oberholzer, Hans-Rudolf; Hammelehle, Andreas; Mayer, Jochen

    2017-01-01

    Root biomass is one of the most relevant root parameters for studies of plant response to environmental change, soil carbon modeling or estimations of soil carbon sequestration. A major source of error in root biomass quantification of agricultural crops in the field is the presence of extraneous organic matter in soil: dead roots from previous crops, weed roots, incorporated above ground plant residues and organic soil amendments, or remnants of soil fauna. Using the isotopic difference between recent maize root biomass and predominantly C3-derived extraneous organic matter, we determined the proportions of maize root biomass carbon of total carbon in root samples from the Swiss long-term field trial "DOK." We additionally evaluated the effects of agricultural management (bio-organic and conventional), sampling depth (0-0.25, 0.25-0.5, 0.5-0.75 m) and position (within and between maize rows), and root size class (coarse and fine roots) as defined by sieve mesh size (2 and 0.5 mm) on those proportions, and quantified the success rate of manual exclusion of extraneous organic matter from root samples. Only 60% of the root mass that we retrieved from field soil cores was actual maize root biomass from the current season. While the proportions of maize root biomass carbon were not affected by agricultural management, they increased consistently with soil depth, were higher within than between maize rows, and were higher in coarse (>2 mm) than in fine (≤2 and >0.5) root samples. The success rate of manual exclusion of extraneous organic matter from root samples was related to agricultural management and, at best, about 60%. We assume that the composition of extraneous organic matter is strongly influenced by agricultural management and soil depth and governs the effect size of the investigated factors. Extraneous organic matter may result in severe overestimation of recovered root biomass and has, therefore, large implications for soil carbon modeling and estimations

  8. A Search for Weakly Interacting Particles with the Cryogenic Dark Matter Search Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Bruch, Tobias [Univ. of Zurich (Switzerland)

    2010-01-01

    Dark matter particles cannot only be detected directly in laboratories, but also indirectly by their annihilation products. Previous predictions of the neutrino flux from WIMP annihilation in the Earth and the Sun have assumed that galactic dark matter is distributed according to the SHM. Although the dark disc has a local density comparable to the dark halo, its higher phase space density at low velocities greatly enhances capture rates in the Sun and Earth. For typical dark disc properties, the resulting muon flux from the Earth is increased by three orders of magnitude over the SHM, while for the Sun the increase is one order of magnitude. This significantly increases the prospects of neutrino telescopes to fix or constrain parameters in WIMP models. The flux from the Earth is extremely sensitive to the detailed properties of the dark disc, while the flux from the Sun is more robust.

  9. The Electron Recoil Response of the XENON1T Dark Matter Experiment

    Science.gov (United States)

    Shockley, Evan; Xenon1T Collaboration

    2017-01-01

    XENON1T employs a two-phase xenon TPC to search for dark matter by detecting scintillation light produced by nuclear recoils in a 2 ton active volume of liquid xenon. However, nuclear recoils are not the only recoils that can occur since radiogenic electronic recoils are possible. Our only way of differentiating nuclear and electronic recoils is by comparing the relative fraction of scintillation (S1) and ionization (S2) signals. For the first Science Run of XENON1T, we must understand the response of our detector to S1 and S2 signals at the low keV energies where dark matter will present itself. Therefore, I will be discussing the current understanding of our signal and detection mechanisms at these energies. This work includes work using sources such as the Rn220 technique developed by XENON collaborators for understanding our rejection of electronic recoils.

  10. Matter Scatter and Energy Anarchy. The Second Law of Thermodynamics is Simply Common Experience.

    Science.gov (United States)

    Ross, Keith A.

    1988-01-01

    Shows that the second law of thermodynamics is in the common experience of many people and if taught first, before the law of conservation, can result in fewer misconceptions among pupils. Stresses the use of common experiences in teaching. (CW)

  11. Applications of an Y-88/Be photo-neutron calibration source to Dark Matter and Neutrino Experiments

    CERN Document Server

    Collar, J I

    2013-01-01

    The low-energy monochromatic neutron emission from an Y-88/Be source can be exploited to mimic the few keVnr nuclear recoils expected from low-mass Weakly Interacting Massive Particles (WIMPs) and coherent scattering of neutrinos off nuclei. Using this source, a ~<10% quenching factor is measured for sodium recoils below 24 keVnr in NaI[Tl]. This is considerably smaller than the 30% typically adopted in the interpretation of the DAMA/LIBRA dark matter experiment, resulting in an increase of its tension with other negative searches. The method is illustrated for other target materials (superheated and noble liquids).

  12. Predicting medical school and internship success: does the quality of the research and clinical experience matter?

    Science.gov (United States)

    Paolino, Nathalie D; Artino, Anthony R; Saguil, Aaron; Dong, Ting; Durning, Steven J; DeZee, Kent J

    2015-04-01

    This article explores specific aspects of self-reported clinical and research experience and their relationship to performance in medical training. This is a retrospective cohort study conducted at the Uniformed Services University. The American Medical College Application Service application was used to discern students' self-reported clinical and research experience. Two authors applied a classification scheme for clinical and research experience to the self-reported experiences. Study outcomes included medical school grade point average (GPA), U.S. Medical Licensing Examination (USMLE) scores, and intern expertise and professionalism scores. A linear regression analysis was conducted for each outcome while controlling for prematriculation GPA. Data were retrieved on 1,020 matriculants. There were several statistically significant but small differences across outcomes when comparing the various categories of clinical experience with no clinical experience. The technician-level experience group had a decrease of 0.1 in cumulative GPA in comparison to students without self-reported clinical experience (p = 0.004). This group also performed 5 points lower on the USMLE Step 2 than students who did not report clinical experience (p = 0.013). The various levels of self-reported research experience were unrelated to success in medical school and graduate medical education. These findings indicate that self-reported technician-level clinical experience is related to a small reduction in typically reported outcomes in medical school. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  13. Lab-in-a-box @ school: Exiting hands-on experiments in soft matter physics

    Science.gov (United States)

    Jacobs, Karin; Brinkmann, Martin; Müller, Frank

    2015-03-01

    Soft materials like liquids and polymers are part of everyday life, yet at school, this topic is rarely touched. Within the priority program SPP 1064 'Nano- and Microfluidics' of the German Science Foundation, we designed an outreach project that allows pupils (age 14 to 18) to perform hands-on experiments (www.labinabox.de). The experiments allow them e.g. to feel viscosity and viscoelasticity, experience surface tension or see structure formation. We call the modus operandi 'subjective experiments' to contrast them with the scientifically objective experiments, which pupils often describe as being boring. Over a dozen different experiments under the topic 'physics of fluids' are collected in a big box that travels to the school. Three other topics of boxes are available, 'physics of light, 'physics of liquid crystals', and 'physics of adhesion and friction'. Each experiment can be performed by 1-3 pupils within 10 - 20 min. That way, each scholar can perform 6 to 8 different small experiments within one topic. 'Subjective experiments' especially catch the attention of girls without disadvantaging boys. Both are fascinated by the hands-on physics experience and are therefore eager to perform also 'boring' objective experiments. Morover, before/after polls reveal that their interest in physics has greatly advanced. The project can easily be taken over and/or adapted to other topics in the natural sciences. Financial support of the German Science Foundation DFG is acknowledged.

  14. Unveiling the nature of dark matter with high redshift 21 cm line experiments

    OpenAIRE

    Evoli, Carmelo; Mesinger, Andrei; Ferrara, Andrea

    2014-01-01

    Observations of the redshifted 21 cm line from neutral hydrogen will open a new window on the early Universe. By influencing the thermal and ionization history of the intergalactic medium (IGM), annihilating dark matter (DM) can leave a detectable imprint in the 21 cm signal. Building on the publicly available 21cmFAST code, we compute the 21 cm signal for a 10 GeV WIMP DM candidate. The most pronounced role of DM annihilations is in heating the IGM earlier and more uniformly than astrophysic...

  15. Dark Matter Searches and Combined Interpretations at the ATLAS Experiment at 13 TeV

    CERN Document Server

    Beacham, James; The ATLAS collaboration

    2016-01-01

    Dark matter (DM) particles can be produced at the LHC in association with other particles, which mainly come from initial state radiation. Searches for such phenomena in events with jets, photons, electroweak gauge bosons or Higgs bosons recoiling against large missing transverse momentum (originating from DM particles) in ATLAS at 13 TeV are presented. The results are interpreted in the framework of simplified models with pair production of Weakly Interacting Massive Particles (WIMPs) and effective field theories. Constraints from dijet searches are compared with results from the “Mono-X” searches, providing combined interpretation in the framework of simplified model.

  16. FPGA-based Trigger System for the LUX Dark Matter Experiment

    CERN Document Server

    Akerib, D S; Bai, X; Bailey, A J; Balajthy, J; Beltrame, P; Bernard, E P; Bernstein, A; Biesiadzinski, T P; Boulton, E M; Bradley, A; Bramante, R; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chapman, J J; Chiller, A A; Chiller, C; Currie, A; Cutter, J E; Davison, T J R; de Viveiros, L; Dobi, A; Dobson, J E Y; Druszkiewicz, E; Edwards, B N; Faham, C H; Fiorucci, S; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C R; Hanhardt, M; Haselschwardt, S J; Hertel, S A; Hogan, D P; Horn, M; Huang, D Q; Ignarra, C M; Ihm, M; Jacobsen, R G; Ji, W; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, N A; Lee, C; Lenardo, B G; Lesko, K T; Lindote, A; Lopes, M I; Malling, D C; Manalaysay, A G; Mannino, R L; Marzioni, M F; McKinsey, D N; Mei, D -M; Mock, J; Moongweluwan, M; Morad, J A; Murphy, A St J; Nehrkorn, C; Nelson, H N; Neves, F; O'Sullivan, K; Oliver-Mallory, K C; Ott, R A; Palladino, K J; Pangilinan, M; Pease, E K; Phelps, P; Reichhart, L; Rhyne, C; Shaw, S; Shutt, T A; Silva, C; Skulski, W; Solovov, V N; Sorensen, P; Stephenson, S; Sumner, T J; Szydagis, M; Taylor, D J; Taylor, W; Tennyson, B P; Terman, P A; Tiedt, D R; To, W H; Tripathi, M; Tvrznikova, L; Uvarov, S; Verbus, J R; Webb, R C; White, J T; Whitis, T J; Witherell, M S; Wolfs, F L H; Yen, M; Yin, J; Young, S K; Zhang, C

    2015-01-01

    LUX is a two-phase (liquid/gas) xenon time projection chamber designed to detect nuclear recoils resulting from interactions with dark matter particles. Signals from the detector are processed with an FPGA-based digital trigger system that analyzes the incoming data in real-time. It enables first pass selection of events of interest based on their pulse shape characteristics, pulse separation, and 3D localization. This document is an overview of the systems capabilities, its inner workings, and its performance.

  17. Extraction of Physics Signals Near Threshold with Germanium Detectors in Neutrino and Dark Matter Experiments

    CERN Document Server

    Soma, A K; Lin, F K; Singh, M K; Jiang, H; Liu, S K; Singh, L; Wu, Y C; Yang, L T; Zhao, W; Agartioglu, M; Asryan, G; Chuang, Y C; Deniz, M; Hsu, C L; Hsu, Y H; Huang, T R; Li, H B; Li, J; Liao, F T; Liao, H Y; Lin, C W; Lin, S T; Ma, J L; Sharma, V; Shen, Y T; Singh, V; Su, J; Subrahmanyam, V S; Tseng, C H; Wang, J J; Wong, H T; Xu, Y; Yang, S W; Yu, C X; Yuan, X C; Yue, Q; Zeyre, M

    2014-01-01

    Germanium ionization detectors with sensitivities as low as 100 eVee open new windows for the studies of neutrino and dark matter physics. The physics motivations of sub-keV germanium detectors are summarized. The amplitude of physics signals is comparable to those due to fluctuations of the pedestal electronic noise. Various experimental issues have to be attended before the promises of this new detector technique can be fully exploited. These include quenching factors, energy definition and calibration, signal triggering and selection together with their associated inefficiencies derivation. The efforts and results of an R&D program to address these challenges are presented.

  18. Search for Exotic Forms of Strange Matter in the ALICE Experiment

    CERN Document Server

    Coffin, J P; CERN. Geneva; Fintz, P; Guillaume, G; Jundt, F; Michalon, A; Rami, F; Roy, C

    1995-01-01

    abstractINT-95-49 Simulations have been performed with the aim to estimate the minimum yield within an event required for an exotic form of strange matter (Strangelet/Memo's) to be seen with the central part of the ALICE detector. The calculations are restricted to specific assumptions on the Strangelet characteristics: Z=0-2. A≅2-15 GeV/c2, and ~10-20s and 10-7s for the charge, mass and lifetime, respectively.

  19. 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

  20. New upper limit on strange quark matter abundance in cosmic rays with the PAMELA space experiment.

    Science.gov (United States)

    Adriani, O; Barbarino, G C; Bazilevskaya, G A; Bellotti, R; Boezio, M; Bogomolov, E A; Bongi, M; Bonvicini, V; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carlson, P; Casolino, M; Castellini, G; De Donato, C; De Santis, C; De Simone, N; Di Felice, V; Formato, V; Galper, A M; Karelin, A V; Koldashov, S V; Koldobskiy, S; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malakhov, V; Marcelli, L; Martucci, M; Mayorov, A G; Menn, W; Mergè, M; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Munini, R; Osteria, G; Palma, F; Panico, B; Papini, P; Pearce, M; Picozza, P; Ricci, M; Ricciarini, S B; Sarkar, R; Scotti, V; Simon, M; Sparvoli, R; Spillantini, P; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G; Voronov, S A; Yurkin, Y T; Zampa, G; Zampa, N

    2015-09-11

    In this work we present results of a direct search for strange quark matter (SQM) in cosmic rays with the PAMELA space spectrometer. If this state of matter exists it may be present in cosmic rays as particles, called strangelets, having a high density and an anomalously high mass-to-charge (A/Z) ratio. A direct search in space is complementary to those from ground-based spectrometers. Furthermore, it has the advantage of being potentially capable of directly identifying these particles, without any assumption on their interaction model with Earth's atmosphere and the long-term stability in terrestrial and lunar rocks. In the rigidity range from 1.0 to ∼1.0×10^{3}  GV, no such particles were found in the data collected by PAMELA between 2006 and 2009. An upper limit on the strangelet flux in cosmic rays was therefore set for particles with charge 1≤Z≤8 and mass 4≤A≤1.2×10^{5}. This limit as a function of mass and as a function of magnetic rigidity allows us to constrain models of SQM production and propagation in the Galaxy.

  1. Low Background Stainless Steel for the Pressure Vessel in the PandaX-II Dark Matter Experiment

    CERN Document Server

    Zhang, Tao; Ji, Xiangdong; Liu, Jianglai; Liu, Xiang; Wang, Xuming; Yao, Chunfa; Yuan, Xunhua

    2016-01-01

    We report on the custom produced low radiation background stainless steel and the welding rod for the PandaX experiment, one of the deep underground experiments to search for dark matter and neutrinoless double beta decay using xenon. The anthropogenic 60 Co concentration in these samples is at the range of 1 mBq/kg or lower. We also discuss the radioactivity of nuclear-grade stainless steel from TISCO which has a similar background rate. The PandaX-II pressure vessel was thus fabricated using the stainless steel from CISRI and TISCO. Based on the analysis of the radioactivity data, we also made discussions on potential candidate for low background metal materials for future pressure vessel development.

  2. Low background stainless steel for the pressure vessel in the PandaX-II dark matter experiment

    Science.gov (United States)

    Zhang, T.; Fu, C.; Ji, X.; Liu, J.; Liu, X.; Wang, X.; Yao, C.; Yuan, Xunhua

    2016-09-01

    We report on the custom produced low radiation background stainless steel and the welding rod for the PandaX experiment, one of the deep underground experiments to search for dark matter and neutrinoless double beta decay using xenon. The anthropogenic 60Co concentration in these samples is at the range of 1 mBq/kg or lower. We also discuss the radioactivity of nuclear-grade stainless steel from TISCO which has a similar background rate. The PandaX-II pressure vessel was thus fabricated using the stainless steel from CISRI and TISCO. Based on the analysis of the radioactivity data, we also made discussions on potential candidate for low background metal materials for future pressure vessel development.

  3. Communication with Parents and Peers on Sexual Matters: the Experience of Adolescents in the Northeastern of China

    Institute of Scientific and Technical Information of China (English)

    Li-ying ZHANG; Iqbal Shah; Wendy Baldwin

    2006-01-01

    Objective To analyze the status of parent-child communication on sexual matters and its relationship to the sexual behaviors of adolescents.Methods The data were obtained from a study which was conducted in Changchun city of China in 2001. Unmarried adolescents aged 15-19 years old(322 males and 360 females) were selected for this analysis.Results Ten percent of adolescents reported having experience of sexual intercourse (16% of male and 5% of female). The percentages of adolescents communicating with peers, mothers and fathers were 35%, 30% and 17%, respectively. Males were more likely to talk about sexual issues with peer, while females were more likely to talk with mothers. Significant difference was also noted between the ratio of communication on sexual matters and having a girl/boy friend with peers and with parents. There was a statistically significant relationship between sexual experience and communication with fathers among male adolescents. Despite the fact that parents are the most closest care providers, adolescents obtained most of the sex information from "reading materials"and from "teachers ", but not from their parents. There was an age difference in the main source of obtaining sexual information. Younger adolescents obtained sexual information mainly from teachers while older adolescents mainly from reading materials.Conclusion In addition to schools and reading materials, parents should serve as an important source of information on sexual education as well.

  4. Graduate Social Work Education and Cognitive Complexity: Does Prior Experience Really Matter?

    Science.gov (United States)

    Simmons, Chris

    2014-01-01

    This study examined the extent to which age, education, and practice experience among social work graduate students (N = 184) predicted cognitive complexity, an essential aspect of critical thinking. In the regression analysis, education accounted for more of the variance associated with cognitive complexity than age and practice experience. When…

  5. Understanding statin non-adherence: knowing which perceptions and experiences matter to different patients.

    NARCIS (Netherlands)

    Wouters, H.; Dijk, L. van; Geers, H.C.J.; Winters, N.A.; Geffen, E.C.G. van; Stiggelbout, A.M.; Bouvy, M.L.

    2016-01-01

    Background: Non-adherence to statins is substantial and is associated with numerous perceptions and experiences. However, time limits in clinical practice constrain in depth explorations of these perceptions and experiences. Objectives: To propose and examine a strategy aimed at an efficient

  6. FPGA-based trigger system for the LUX dark matter experiment

    Science.gov (United States)

    Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bradley, A.; Bramante, R.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; de Viveiros, L.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Manalaysay, A. G.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O`Sullivan, K.; Oliver-Mallory, K. C.; Ott, R. A.; Palladino, K. J.; Pangilinan, M.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Skulski, W.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Yin, J.; Young, S. K.; Zhang, C.

    2016-05-01

    LUX is a two-phase (liquid/gas) xenon time projection chamber designed to detect nuclear recoils resulting from interactions with dark matter particles. Signals from the detector are processed with an FPGA-based digital trigger system that analyzes the incoming data in real-time, with just a few microsecond latency. The system enables first pass selection of events of interest based on their pulse shape characteristics and 3D localization of the interactions. It has been shown to be > 99 % efficient in triggering on S2 signals induced by only few extracted liquid electrons. It is continuously and reliably operating since its full underground deployment in early 2013. This document is an overview of the systems capabilities, its inner workings, and its performance.

  7. ZnWO_4 crystals as detectors for double beta decay and dark matter experiments

    CERN Document Server

    Danevich, F A; Nagorny, S S; Poda, D V; Tretyak, V I; Yurchenko, S S; Zdesenko, Y G; Zdesenko, Yu.G.

    2004-01-01

    Energy resolution, alpha/beta ratio, and the pulse shape discrimination ability of the ZnWO_4 crystal scintillators were studied. The radioactive contamination of a ZnWO_4 crystal was investigated in the Solotvina Underground Laboratory. Possibilities to apply ZnWO_4 crystals for the dark matter and double beta decay searches are discussed. New improved half-life limits on double beta decay in zinc isotopes were established, in particular, for EC\\beta^+ decay of 64-Zn as: T_1/2^2nu > 8.9 10^18 yr and T_1/2^0nu > 3.6 10^18 yr, both at 68% CL.

  8. ZnWO{sub 4} crystals as detectors for 2{beta} decay and dark matter experiments

    Energy Technology Data Exchange (ETDEWEB)

    Danevich, F.A. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine)]. E-mail: danevich@kinr.kiev.ua; Kobychev, V.V. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Nagorny, S.S. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Poda, D.V. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Tretyak, V.I. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Yurchenko, S.S. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine); Zdesenko, Yu.G. [Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680 Kiev (Ukraine)

    2005-06-01

    Energy resolution, {alpha}/{beta} ratio, and the pulse shape discrimination ability of the ZnWO{sub 4} crystal scintillators were studied. The radioactive contamination of a ZnWO{sub 4} crystal was investigated in the Solotvina Underground Laboratory. Possibilities to apply ZnWO{sub 4} crystals for the dark matter and double beta decay searches are discussed. New improved half-life limits on double beta decay in zinc isotopes were established, in particular, for -bar {beta}{sup +} decay of {sup 64}Zn as: T{sub 1/2}{sup 2{nu}}>=8.9x10{sup 18} years and T{sub 1/2}{sup 0{nu}}>=3.6x10{sup 18} years, both at 68% CL.

  9. PandaX: A Liquid Xenon Dark Matter Experiment at CJPL

    CERN Document Server

    Cao, X G; Chen, Y H; Cui, X Y; Fang, D Q; Fu, C B; Giboni, K L; Gong, H W; Guo, G D; He, M; Hu, J; Huang, X T; Ji, X D; Ju, Y L; Li, S L; Lin, Q; Liu, H X; Liu, J L; Liu, X; Lorenzon, W; Ma, Y G; Mao, Y J; Ni, K X; Pushkin, K; Ren, X X; Schubnell, M; Shen, M B; Shi, Y J; Stephenson, S; Tan, A D; Tarle, G; Wang, H W; Wang, J M; Wang, M; Wang, X M; Wang, Z; Wei, Y H; Wu, S Y; Xiao, M J; Xiao, X; Xie, P W; Ye, T; You, Y H; Zeng, X H; Zhang, H; Zhang, T; Zhao, H Y; Zhao, L; Zhou, X P; Zhu, Z H

    2014-01-01

    PandaX is a large upgradable liquid-xenon detector system that can be used for both direct dark-matter detection and $^{136}$Xe double-beta decay search. It is located in the Jinping Deep-Underground Laboratory in Sichuan, China. The detector operates in dual-phase mode, allowing detection of both prompt scintillation, and ionization charge through proportional scintillation. The central time projection chamber will be staged, with the first stage accommodating a target mass of about 120\\,kg. In stage II, the target mass will be increased to about 0.5\\,ton. In the final stage, the detector can be upgraded to a multi-ton target mass. In this paper a detailed description of the stage-I detector design and performance results established during the commissioning phase is presented.

  10. UV degradation of the optical properties of acrylic for neutrino and dark matter experiments

    Energy Technology Data Exchange (ETDEWEB)

    Littlejohn, B; Heeger, K M; Wise, T [Physics Department, University of Wisconsin, Madison, WI, 53706 (United States); Gettrust, E; Lyman, M [Madison West High School, Madison, WI, 53726 (United States)], E-mail: littlejohn@wisc.edu

    2009-09-15

    UV-transmitting (UVT) acrylic is a commonly used light-propagating material in neutrino and dark matter detectors as it has low intrinsic radioactivity and exhibits low absorption in the detectors' light producing regions, from 350 nm to 500 nm. Degradation of optical transmittance in this region lowers light yields in the detector, which can affect energy reconstruction, resolution, and experimental sensitivities. We examine transmittance loss as a result of short- and long-term UV exposure for a variety of UVT acrylic samples from a number of acrylic manufacturers. Significant degradation peaking at 343 nm was observed in some UVT acrylics with as little as three hours of direct sunlight, while others exhibited softer degradation peaking at 310 nm over many days of exposure to sunlight. Based on their measured degradation results, safe time limits for indoor and outdoor UV exposure of UVT acrylic are formulated.

  11. Cosmic Ray Experiments and the Implications for Indirect Detection of Dark Matter

    Science.gov (United States)

    Mitchell, John W.; Ormes, Jonathan F.; Streitmatter, Robert E.

    2013-01-01

    Detection of cosmic-ray antiprotons was first reported by Golden et al. in 1979 and their existence was firmly established by the BESS and IMAX collaborations in the early 1990s. Increasingly precise measurements of the antiproton spectrum, most recently from BESS-Polar and PAMELA, have made it an important tool for investigating cosmic-ray transport in the galaxy and heliosphere and for constraining dark-matter models. The history of antiproton measurements will be briefly reviewed. The current status will be discussed, focusing on the results of BESS-Polar II and their implications for the possibility of antiprotons from primordial black hole evaporation. The current results of the BESS-Polar II antihelium search are also presented.

  12. Direct dark matter detection with the DarkSide-50 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pagani, Luca [Univ. of Genoa (Italy)

    2017-01-01

    The existence of dark matter is known because of its gravitational effects, and although its nature remains undisclosed, there is a growing indication that the galactic halo could be permeated by weakly interacting massive particles (WIMPs) with mass of the order of $100$\\,GeV/c$^2$ and coupling with ordinary matter at or below the weak scale. In this context, DarkSide-50 aims to direct observe WIMP-nucleon collisions in a liquid argon dual phase time-projection chamber located deep underground at Gran Sasso National Laboratory, in Italy. In this work a re-analysis of the data that led to the best limit on WIMP-nucleon cross section with an argon target is done. As starting point of the new approach, the energy reconstruction of events is considered: a new energy variable is developed where anti-correlation between ionization and scintillation produced by an interaction is taken into account. As first result, a better energy resolution is achieved. In this new energy framewor k, access is granted to micro-physics parameters fundamental to argon scintillation such as the recombination and quenching as a function of the energy. The improved knowledge of recombination and quenching allows to develop a new model for distinguish between events possibly due to WIMPs and backgrounds. In light of the new model, the final result of this work is a more stringent limit on spin independent WIMP-nucleon cross section with an argon target. This work was supervised by Marco Pallavicini and was completed in collaboration with members of the DarkSide collaboration.

  13. Experience matters: The impact of doing versus watching on infants’ subsequent perception of tool use events

    Science.gov (United States)

    Sommerville, Jessica A.; Hildebrand, Elina A.; Crane, Catharyn C.

    2008-01-01

    Prior work suggests that active experience impacts infants’ understanding of simple actions. The present studies compared the impact of active and observational experience on infants’ ability to identify the goal of a novel tool use event. Infants received active practice and training using a cane to retrieve an out-of-reach toy, or matched observational experience, prior to taking part in a habituation paradigm that assessed infants’ ability to identify the goal of another person’s tool use acts. Active training alone facilitated 10-month-old infants’ ability to identify the goal of the tool use event. Active experience using tools may enable infants to build motor representations of tool use events that subsequently guide action perception and support action understanding. PMID:18793059

  14. "EGM" (Electrostatics of Granular Matter): A Space Station Experiment to Examine Natural Particulate Systems

    Science.gov (United States)

    Marshall, J.; Sauke, T.; Buehler, M.; Farrell, W.; Green, R.; Birchenough, A.

    1999-01-01

    A granular-materials experiment is being developed for a 2002 launch for Space Station deployment. The experiment is funded by NASA HQ and managed through NASA Lewis Research Center. The experiment will examine electrostatic aggregation of coarse granular materials with the goals of (a) obtaining proof for an electrostatic dipole model of grain interactions, and (b) obtaining knowledge about the way aggregation affects the behavior of natural particulate masses: (1) in unconfined dispersions (clouds such as nebulae, aeolian dust palls, volcanic plumes), (2) in semi-confined, self-loaded masses as in fluidized flows (pyroclastic surges, avalanches) and compacted regolith, or (3) in semi-confined non-loaded masses as in dust layers adhering to solar cells or space suits on Mars. The experiment addresses both planetary/astrophysical issues as well as practical concerns for human exploration of Mars or other solar system bodies. Additional information is contained in the original.

  15. EARTHWORM PONTOSCOLEXCORETHRURUS AND NITROGEN MINERALIZATION RATE IN INCUBATION EXPERIMENT WITH DIFFERENT QUALITY ORGANIC MATTERS FROM SUGARAGRO-INDUSTRY WASTE

    Directory of Open Access Journals (Sweden)

    J.B.Naik

    2014-02-01

    Full Text Available To investigate the effect of earthworm inoculation on N mineralization rates of different quality organic matters from sugar agro-industry waste, we conducted a green house incubation experiment for 14 weeks in pots containing 7 kg dry soil. There are 12 treatment combinations.Factor I waswith (P and without inoculation of P.corethrurus (N. Factor II was the type of OM which consisted of six levels: (1 without application of OM (control, (2 cow manure (CM, (3 filter cake (FC, (4 sugarcane trash (ST, (5 a mixture of CM + FC and (6 a mixture of CM + ST. The treatments were arranged in a factorial randomized block design with three replications. The amount of released N-NH4 +and N-NO3 - or mineral N was measured during incubation time from 1, 2, 4, 8, and 14 weeks after inoculation of earthworms. There was a significant effect of earthworm inoculation on N mineralization rate of different quality organic matters. Overall, rate of net N mineralization were higher in treatments with earthworm inoculation than without earthworm inoculation and the magnitude of the increase appears to dependent on the quality of organic matters. The largest difference were seen on ST and CM+ST treatments with the increase by 90 % and 157 % and the constant of N mineralization rate by 0.0147 and 0.0180 week-1 for the treatment with earthwormsinoculation.These results suggested that application of sugar agro-industry waste although having low quality can improve soil N availability in sugarcane land when aided by P.corethrurus activity.

  16. Experience matters: Dogs (Canis familiaris) infer physical properties of objects from movement clues.

    Science.gov (United States)

    Kuroshima, Hika; Nabeoka, Yukari; Hori, Yusuke; Chijiiwa, Hitomi; Fujita, Kazuo

    2017-03-01

    Reasoning about physical properties of objects such as heaviness by observing others' actions toward them is important and useful for adapting to the environment. In this study, we asked whether domestic dogs (Canis familiaris) can use a human's action to infer a physical property of target objects. In Experiment 1, dogs watched an experimenter opening two differently loaded swinging doors with different corresponding degrees of effort, and then were allowed to open one of the doors. Dogs chose randomly between the two doors. In Experiment 2, we gave new dogs the same test as in Experiment 1, but only after giving them experience of opening the doors by themselves, so that they already knew that the doors could be either light or heavy. In this test the dogs reliably chose the light door. These results indicate that dogs are able to infer physical characteristics of objects from the latters' movement caused by human action, but that this inferential reasoning requires direct own experience of the objects.

  17. Probing ultrafast dynamics of condensed matter with pump and probe experiments with X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Giles, Carlos; Celestre, Rafael; Tasca, Kelin R.; Vescovi, Rafael; Faria, Guilherme; Dias, Carlos S.; Tomm, Natasha; Cordeiro, Cristiano M.B. [Universidade Estadual de Campinas (IFGW/UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin; Silva, Rene Nome [Universidade Estadual de Campinas (IQ/UNICAMP), SP (Brazil). Inst. de Quimica

    2012-07-01

    Full text: In this presentation we will describe recent advances in the route to start ultrafast studies with X-rays in Brazil. From one side pump and probe experiments using synchrotron radiation facilities will be described, showing how the thermal expansion of an invar alloy is not occurring at the picosecond time scales after heating the sample with a femtosecond infrared laser pulse. We will also describe the experimental setup at the LNLS in Campinas were we probe the fast response of a piezoelectric material to a 1 ns electric pulse recorded by a pump and probe X-ray diffraction experiment at the XRD2 LNLS beamline. We will also present the first results of the production of sub-picosecond X-ray pulses using an amplified infrared laser at the Ultrafast Laboratory of DEQ/IFGW. The instrumentation developed at UNICAMP together with the first setup for a pump and probe experiment will be presented. Characteristic radiation of various targets (TiK{alpha}, FeK{alpha}, CuK{alpha}) have been measured at a repetition rate of 1 kHz showing unambiguously our capability of producing a pulsed X-ray source for time resolved x-ray diffraction experiments. Experiments to measure the pulse width of the X-ray radiation are under development and the latest results will be presented. All these efforts open the path to the nucleation of a research group in ultrafast studies using X-rays in Brazil. (author)

  18. "Phase freezeout" in isentropically expanding matter

    CERN Document Server

    Iosilevskiy, Igor

    2014-01-01

    Features of isentropic expansion of warm dense matter (WDM) created by intense energy fluxes (strong shock compression or instant isochoric heating by laser or heavy ions) are under discussion in situation when ($i$) -- thermodynamic trajectory of such expansion crosses binodal of liquid-gas phase transition, and ($ii$) -- expansion within the two-phase region is going along equilibrium branch (not metastable one) of the two-phase mixture isentrope. It is known in the plane case that because of break in the expansion isentrope at binodal point (in $P-V$ plane) i.e. jump of sound velocity in this point, there appears extended zone ("boiling layer") of uniformity in expanding material with constant thermodynamic and kinematic parameters. It corresponds just to the state on this binodal of boiling liquid. The point is that because of self-similarity of such expansion (in plane case) this boiling layer contains finite and fixed part of whole expanding material. This property makes it possible (at least formally) ...

  19. First results of the IGEX dark matter experiment at the Canfranc Underground Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Cebrian, S.; Morales, A.; Aalseth, C.E.; Avignone, F.T.; Brodzinski, R.L.; Garcia, E.; Gonzalez, D.; Hensley, W.K.; Irastorza, I.G.; Kirpichnikov, I.V.; Klimenko, A.A.; Miley, H.S.; Morales, J.; Ortiz de Solorzano, A.; Osetrov, S.B.; Pogosov, V.S.; Puimedon, J.; Reeves, J.H.; Sarsa, M.L.; Scopel, S.; Smolnikov, A.A.; Tamanyan, A.G.; Vasenko, A.A.; Vasiliev, S.I.; Villar, J.A

    2001-04-01

    The enriched {sup 76}Ge double-beta decay detectors from the International Germanium EXperiment (IGEX), operating in the Canfranc Underground Laboratory with an overbuden of 2450 m.w.e., were recently upgraded to use them also in a search for WIMPs. This paper presents a description of the experiment and the data analysis as well as a new exclusion plot, {sigma}(m), derived from the IGEX data for WIMP-nucleon spin-independent interaction. To obtain this result, 30 days of data from one 2-kg IGEX detector, with an energy threshold E{sub thr} {approx} 4 keV, have been considered. These results improve the exclusion limits derived from other conventional ionization germanium experiments in the {approx} 50 GeV DAMA region.

  20. Dark matter search in the Milano Double Beta experiment and prospects for the CUORE project

    CERN Document Server

    Guiliani, A; Brofferio, C; Bucci, C; Capelli, S; Cremonesi, O; Fiorini, Ettore; Nucciotti, A; Pavan, M M; Pedretti, M; Pessina, G; Pirro, S; Pobes, C; Previtali, E; Sisti, M; Vanzini, M; Zanotti, L

    2002-01-01

    A Double Beta Decay experiment performed by the Milano group at the Laboratori Nazionali del Gran Sasso (Mi DBD experiment) consists of 20 TeO sub 2 crystals operated as bolometers at T approx = 10mK. An 89-day low-threshold background spectrum, collected with two 340 g bolometers, was selected and analyzed to search for a possible WIMP signal. The exclusion plot in a WIMP mass -- cross section plane was evaluated, assuming WIMP-nucleus spin-independent interaction. WIMP-nucleon cross sections larger than 10 sup - sup 4 pb are excluded between 30 and 100 GeV WIMP masses. The planned expansions of the present experiment, named CUORICINO and CUORE, are presented in terms of sensitivity to WIMP search, considering also the seasonal modulation approach, made possible by the large masses of the future arrays (40 kg for CUORICINO and 760 kg for CUORE).

  1. "What's (the) Matter?", A Show on Elementary Particle Physics with 28 Demonstration Experiments

    CERN Document Server

    Dreiner, Herbi K; Borzyszkowski, Mikolaj; Braun, Maxim; Faßbender, Alexander; Hampel, Julia; Hansen, Maike; Hebecker, Dustin; Heepenstrick, Timo; Heinz, Sascha; Hortmanns, Katharina; Jost, Christian; Kortmann, Michael; Kruckow, Matthias U; Leuteritz, Till; Lütz, Claudia; Mahlberg, Philip; Müllers, Johannes; Opferkuch, Toby; Paul, Ewald; Pauli, Peter; Rossbach, Merlin; Schaepe, Steffen; Schiffer, Tobias; Schmidt, Jan F; Schüller-Ruhl, Jana; Schürmann, Christoph; Ubaldi, Lorenzo; Wagner-Carena, Sebastian

    2016-01-01

    We present the screenplay of a physics show on particle physics, by the Physikshow of Bonn University. The show is addressed at non-physicists aged 14+ and communicates basic concepts of elementary particle physics including the discovery of the Higgs boson in an entertaining fashion. It is also demonstrates a successful outreach activity heavily relying on the university physics students. This paper is addressed at anybody interested in particle physics and/or show physics. This paper is also addressed at fellow physicists working in outreach, maybe the experiments and our choice of simple explanations will be helpful. Furthermore, we are very interested in related activities elsewhere, in particular also demonstration experiments relevant to particle physics, as often little of this work is published. Our show involves 28 live demonstration experiments. These are presented in an extensive appendix, including photos and technical details. The show is set up as a quest, where 2 students from Bonn with the aid...

  2. Darkside-20k: A 20 ton Liquid Argon Dark Matter Experiment

    Science.gov (United States)

    Back, Henning; Darkside-20k Collaboration

    2016-03-01

    The Darkside-20k detector is the next step in the Darkside dark matter search program at the Laboratori Nazionali del Gran Sasso in Italy. The Darkside detectors have grown in fiducial mass starting with 10kg in Darkside10, to 50 kg in Darkside50, and finally a proposed 20,000 kg fiducial mass, Darkside20k. The Darkside detectors are dual-phase argon TPCs that combine the very powerful scintillation pulse-shape analysis and ionization information to discriminate against background events. Two unique aspects to the Darkside program is the use of an external neutron veto based on borated liquid scintillator, and the use of low radioactivity argon from underground sources as the target. Argon from the atmosphere has an 39Ar activity of 1Bq/kg, which would be the limiting background, but the underground argon is essentially free of 39Ar. Additionally, the detector is placed in a water Cherenkov muon veto. Combining all these techniques allows Darkside-20k to achieve a background-free 100 t-yr exposure accumulated in a 5 yr run. Darkside-20k is expected to start operations in 2020 with data taking starting in 2021, and will be sensitive to WIMP-nucleon interaction cross sections of 1×10-47 cm2 (1x10-46 cm2) for WIMPs of 1 TeV/c2 (10 TeV/c2) mass.

  3. Unveiling the nature of dark matter with high redshift 21 cm line experiments

    CERN Document Server

    Evoli, Carmelo; Ferrara, Andrea

    2014-01-01

    Observations of the redshifted 21 cm line from neutral hydrogen will open a new window on the early Universe. By influencing the thermal and ionization history of the intergalactic medium (IGM), annihilating dark matter (DM) can leave a detectable imprint in the 21 cm signal. Building on the publicly available 21cmFAST code, we compute the 21 cm signal for a 10 GeV WIMP DM candidate. The most pronounced role of DM annihilations is in heating the IGM earlier and more uniformly than astrophysical sources of X-rays. This leaves several unambiguous, qualitative signatures in the redshift evolution of the large-scale ($k\\approx0.1$ Mpc$^{-1}$) 21 cm power amplitude: (i) the local maximum (peak) associated with IGM heating can be lower than the other maxima; (ii) the heating peak can occur while the IGM is in emission against the cosmic microwave background (CMB); (iii) there can be a dramatic drop in power (a global minimum) corresponding to the epoch when the IGM temperature is comparable to the CMB temperature. ...

  4. The AMANDA Experiment status and prospects for indirect Dark Matter detection

    CERN Document Server

    Bergström, L

    1996-01-01

    At the AMANDA South Pole site, four new holes were drilled to depths 2050 m to 2180 m and instrumented with 86 photomultipliers (PMTs) at depths 1520-2000 m. Of these PMTs 79 are working, with 4-ns timing resolution and noise rates 300 to 600 Hz. Various diagnostic devices were deployed and are working. An observed factor 60 increase in scattering length and a sharpening of the distribution of arrival times of laser pulses relative to measurements at 800-1000 m showed that air bubbles are absent below 1500 m. Absorption lengths are 100 to 150 m at wavelengths in the blue and UV to 337 nm. Muon coincidences are seen between the SPASE air shower array and the AMANDA PMTs at 800-1000 m and 1500-1900 m. The muon track rate is 30 Hz for 8-fold triggers and 10 Hz for 10-fold triggers. The present array is the nucleus for a future expanded array. The potential of AMANDA for SUSY dark matter search through the detection of high-energy neutrinos from the centre of the Sun or Earth is discussed.

  5. Race Has Always Mattered: An Intergeneration Look at Race, Space, Place, and Educational Experiences of Blacks

    Directory of Open Access Journals (Sweden)

    Denise G. Yull

    2014-01-01

    Full Text Available Within school settings race continues to be one of the most formidable obstacles for Black children in the United States (US school system. This paper expands the discussions of race in education by exploring how the social links among race, space, and place provide a lens for understanding the persistence of racism in the educational experiences of Black children. This paper examines how differences in a rural versus urban geographical location influence a student’s experience with race, racism, and racial identity across four generations of Black people in the context of school and community. Implications for research and practice are discussed.

  6. Children's Views Matter Too! A Pilot Project Assessing Children's and Adolescents' Experiences of Clinical Psychology Services

    Science.gov (United States)

    Gordon, Michael; Russo, Kate

    2009-01-01

    This pilot study explored the experiences and understanding of clinical psychology practices and services of children and adolescents attending clinical psychology outpatient appointments. Fifteen young participants took part in the study. A content analysis indicated that young children and adolescents have an appropriate understanding of the…

  7. Does Teaching Experience Matter? Examining Biology Teachers' Prior Knowledge for Teaching in an Alternative Certification Program

    Science.gov (United States)

    Friedrichsen, Patricia J.; Abell, Sandra K.; Pareja, Enrique M.; Brown, Patrick L.; Lankford, Deanna M.; Volkmann, Mark J.

    2009-01-01

    Alternative certification programs (ACPs) have been proposed as a viable way to address teacher shortages, yet we know little about how teacher knowledge develops within such programs. The purpose of this study was to investigate prior knowledge for teaching among students entering an ACP, comparing individuals with teaching experience to those…

  8. Children's Views Matter Too! A Pilot Project Assessing Children's and Adolescents' Experiences of Clinical Psychology Services

    Science.gov (United States)

    Gordon, Michael; Russo, Kate

    2009-01-01

    This pilot study explored the experiences and understanding of clinical psychology practices and services of children and adolescents attending clinical psychology outpatient appointments. Fifteen young participants took part in the study. A content analysis indicated that young children and adolescents have an appropriate understanding of the…

  9. Board Games Play Matters: A Rethinking on Children's Aesthetic Experience and Interpersonal Understanding

    Science.gov (United States)

    Chou, Mei-Ju

    2017-01-01

    There has been a growing awareness of the contribution of play to the young children's learning and development. This study aims to investigate the implement of board games play on children's aesthetic experience and interpersonal understanding in Montessori and Constructivist classrooms. With the underlying framework follows a developmentally…

  10. Does Teaching Experience Matter? Examining Biology Teachers' Prior Knowledge for Teaching in an Alternative Certification Program

    Science.gov (United States)

    Friedrichsen, Patricia J.; Abell, Sandra K.; Pareja, Enrique M.; Brown, Patrick L.; Lankford, Deanna M.; Volkmann, Mark J.

    2009-01-01

    Alternative certification programs (ACPs) have been proposed as a viable way to address teacher shortages, yet we know little about how teacher knowledge develops within such programs. The purpose of this study was to investigate prior knowledge for teaching among students entering an ACP, comparing individuals with teaching experience to those…

  11. Understanding Statin Non-Adherence: Knowing Which Perceptions and Experiences Matter to Different Patients.

    Directory of Open Access Journals (Sweden)

    Hans Wouters

    Full Text Available Non-adherence to statins is substantial and is associated with numerous perceptions and experiences. However, time limits in clinical practice constrain in depth explorations of these perceptions and experiences.To propose and examine a strategy aimed at an efficient assessment of a wide array of perceptions and experiences regarding the efficacy, side effects, and practical problems of statins. Furthermore, to assess associations between this wide array of experiences and perceptions and non-adherence and to examine whether patients' 'perceived self-efficacy' moderated these associations.Patients were recruited through community pharmacies. A wide array of specific patient perceptions and experiences was efficiently assessed using the electronic Tailored Medicine Inventory that allows people to skip irrelevant questions. Adherence was measured through self-report and pharmacy refill data.Of the two-hundred twenty-nine patients who participated (mean age 63.9, standard deviation 10.2, 40%-70% doubted the necessity of or lacked knowledge about the efficacy of statins, 20%-35% of the patients were worried about joint and muscle side effects or had experienced these, and 23% had encountered practical problems regarding information about statins, intake of tablets, the package, or the blister. Experiencing more practical problems was associated with increased unintentional non-adherence (Odds ratio 1.54, 95%CI:1.13-2.10, P < 0.01, whereas worrying about side effects was associated with increased intentional non-adherence (Odds ratio 1.90, 95%CI:1.17-3.08, P < 0.01. Higher 'perceived self-efficacy' did not moderate these associations.Insight into patients' specific barriers with regard to appropriate statin use may reveal personal reasons for being non-adherent. The Tailored Medicine Inventory is a promising tool to devise individualized intervention strategies aimed at improving adherence by the clinician-patient alliance.

  12. Understanding Statin Non-Adherence: Knowing Which Perceptions and Experiences Matter to Different Patients.

    Science.gov (United States)

    Wouters, Hans; Van Dijk, Liset; Geers, Harm C J; Winters, Nina A; Van Geffen, Erica C G; Stiggelbout, Anne M; Bouvy, Marcel L

    2016-01-01

    Non-adherence to statins is substantial and is associated with numerous perceptions and experiences. However, time limits in clinical practice constrain in depth explorations of these perceptions and experiences. To propose and examine a strategy aimed at an efficient assessment of a wide array of perceptions and experiences regarding the efficacy, side effects, and practical problems of statins. Furthermore, to assess associations between this wide array of experiences and perceptions and non-adherence and to examine whether patients' 'perceived self-efficacy' moderated these associations. Patients were recruited through community pharmacies. A wide array of specific patient perceptions and experiences was efficiently assessed using the electronic Tailored Medicine Inventory that allows people to skip irrelevant questions. Adherence was measured through self-report and pharmacy refill data. Of the two-hundred twenty-nine patients who participated (mean age 63.9, standard deviation 10.2), 40%-70% doubted the necessity of or lacked knowledge about the efficacy of statins, 20%-35% of the patients were worried about joint and muscle side effects or had experienced these, and 23% had encountered practical problems regarding information about statins, intake of tablets, the package, or the blister. Experiencing more practical problems was associated with increased unintentional non-adherence (Odds ratio 1.54, 95%CI:1.13-2.10, P non-adherence (Odds ratio 1.90, 95%CI:1.17-3.08, P patients' specific barriers with regard to appropriate statin use may reveal personal reasons for being non-adherent. The Tailored Medicine Inventory is a promising tool to devise individualized intervention strategies aimed at improving adherence by the clinician-patient alliance.

  13. Development of cryogenic CMOS Readout ASICs for the Point-Contact HPGe Detectors for Dark Matter Search and Neutrino Experiments

    Science.gov (United States)

    Deng, Zhi; He, Li; Liu, Feng; Liu, Yinong; Xue, Tao; Li, Yulan; Yue, Qian

    2017-05-01

    The paper presents the developments of two cryogenic readout ASICs for the point-contact HPGe detectors for dark matter search and neutrino experiments. Extremely low noise readout electronics were demanded and the capability of working at cryogenic temperatures may bring great advantages. The first ASIC was a monolithic CMOS charge sensitive preamplifier with its noise optimized for ∼1 pF input capacitance. The second ASIC was a waveform recorder based on switched capacitor array. These two ASICs were fabricated in CMOS 350 nm and 180 nm processes respectively. The prototype chips were tested and showed promising results. Both ASICs worked well at low temperature. The preamplifier had achieved ENC of 10.3 electrons with 0.7 pF input capacitance and the SCA chip could run at 9 bit effective resolution and 25 MSPS sampling rate.

  14. Tunable microstrip SQUID amplifiers for the Gen 2 Axion Dark Matter eXperiment (ADMX)

    Science.gov (United States)

    O'Kelley, Sean; Hilton, Gene; Clarke, John; ADMX Collaboration

    2016-03-01

    We present a series of tunable microstrip SQUID (Superconducting Quantum Interference Device) amplifiers (MSAs) for installation in ADMX. The axion dark matter candidate is detected via Primakoff conversion to a microwave photon in a high-Q (~100,000) tunable microwave cavity cooled with a dilution refrigerator in a 7-tesla magnetic field. The microwave photon frequency ν is a function of the unknown axion mass, so both the cavity and amplifier must be scanned over a wide frequency range. An MSA is a linear, phase-preserving amplifier consisting of a square washer loop, fabricated from a thin Nb film, incorporating two Josephson tunnel junctions with resistive shunts to prevent hysteresis. The input is coupled via a microstrip made from a square Nb coil deposited over the washer with an intervening insulating layer. Tunability is achieved by terminating the microstrip with GaAs varactors that operate below 100 mK. By varying the varactor capacitance with a bias voltage, the resonant frequency is varied by up to a factor of 2. We demonstrate several devices operating below 100 mK, matched to the discrete operating bands of ADMX at frequencies ranging from 560 MHz to 1 GHz. The MSAs exhibit gains exceeding 20 dB and the associated noise temperatures, measured with a hot/cold load, approach the standard quantum limit (hν/kB) . Supported by DOE Grants DE - FG02 - 97ER41029, DE - FG02 - 96ER40956, DE - AC52 - 07NA27344, DE - AC03 - 76SF00098, and the Livermore LDRD program.

  15. Data acquisition and analysis for the Edelweiss dark matter search experiment; Acquisition et analyse des donnees pour l'experience de recherche de matiere noire EDELWEISS

    Energy Technology Data Exchange (ETDEWEB)

    Fiorucci, S

    2005-09-01

    The EDELWEISS experiment aims to detect WIMPs, hypothetical and elusive particles which could possibly amount for all or part of the dark matter in the universe. For that purpose, it uses cryogenic germanium detectors able to record both the rise in temperature and the ionisation created by a WIMP interaction in the semi-conductor crystal bulk. This thesis work focuses on the last data taking campaign of phase I of the experiment. It is centered around three main points. In a first part, we present the elaboration of a new numerical acquisition system, based on a heat channel trigger, contrary to the previous system which was based on an ionisation channel trigger. In a second part, we expose the complete analysis of the data acquired with this new system, from the calibration of each measurement channel to the extraction of a result in terms of sensitivity to a WIMP signal. Lastly, we dedicate a whole chapter to a further analysis of the high energy data, as well as to the interpretation of the different radioactive backgrounds we observe, in order to prepare the next phase of the experiment due to begin at the end of 2005. (author)

  16. Probing properties of hot and dense QCD matter with heavy flavor in the PHENIX experiment at RHIC

    Directory of Open Access Journals (Sweden)

    Nouicer Rachid

    2015-01-01

    Full Text Available Hadrons carrying heavy quarks, i.e. charm or bottom, are important probes of the hot and dense medium created in relativistic heavy ion collisions. Heavy quarkantiquark pairs are mainly produced in initial hard scattering processes of partons. While some of the produced pairs form bound quarkonia, the vast majority hadronize into particles carrying open heavy flavor. Heavy quark production has been studied by the PHENIX experiment at RHIC via measurements of single leptons from semi-leptonic decays in both the electron channel at mid-rapidity and in the muon channel at forward rapidity. A large suppression and azimuthal anisotropy of single electrons have been observed in Au + Au collisions at 200 GeV. These results suggest a large energy loss and flow of heavy quarks in the hot, dense matter. The PHENIX experiment has also measured J/ψ production at 200 GeV in p + p, d + Au, Cu + Cu and Au + Au collisions, both at mid- and forward-rapidities, and additionally Cu + Au and U + U at forward-rapidities. In the most energetic collisions, more suppression is observed at forward rapidity than at central rapidity. This can be interpreted either as a sign of quark recombination, or as a hint of additional cold nuclear matter effects. The centrality dependence of nuclear modification factor, RAA(pT, for J/ψ in U + U collisions at √sNN = 193 GeV shows a similar trend to the lighter systems, Au + Au and Cu + Cu, at similar energy 200 GeV.

  17. X-ray diffraction at Matter in Extreme Conditions endstation

    Science.gov (United States)

    Xing, Zhou; Galtier, Eric; Lee, Hae Ja; Nagler, Bob

    2015-11-01

    Understanding dynamic response at the atomic level under extreme conditions is highly sought after goal to science frontiers studying warm dense matter, high pressure, geoscience, astrophysics, and planetary science. Thus it is of importance to determine the high pressure phases or metastable phases of material under shock compression. In situ X-ray diffraction technique using LCLS free electron laser X-ray is a powerful tool to record structural behavior and microstructure evolution in dense matter. Shock-induced compression and phase transitions of material lead to changes of the lattice spacing or evolution of new X-ray diffraction patterns. In this talk, we describe a platform dedicated for the X-ray diffraction studies at Matter in Extreme Conditions (MEC), which can be used to reconstruct a complete diffraction pattern from numerous detectors, optimize detector positioning in a timely manner, extract the lattice spacing profiles and texture features. This platform is available to the user community for real-time analysis. We will also discuss experimental results, using this platform, on the crystalline silicon phase transitions up to 60 GPa.

  18. Design, scale-up and characterization of the data acquisition system for the ANAIS dark matter experiment

    CERN Document Server

    Oliván, M A

    2016-01-01

    The ANAIS project has been a long time effort devoted to carry out an experiment to detect dark matter annual modulation with very low background NaI(Tl) detectors. It is expected to be fully commissioned along 2016. This experiment could confirm the DAMA/LIBRA positive signal with the same target and technique. This work was devoted to the design, implementation and characterization of a data acquisition system suitable for the ANAIS experiment, having in mind the ANAIS requirements: very low energy threshold, a background as low as possible in the region of interest, a high enough exposure and a rigorous parameter control in order to monitor systematics. This work describes the Photomultiplier Tubes used by the ANAIS modules and the algorithms and protocol developed in order to pass quality tests to all units. It presents the design and implementation of the electronic front-end for the ANAIS modules and muon tagging system along with the data acquisition software. The analysis software was adapted from the...

  19. First results from the LUX dark matter experiment at the Sanford Underground Research Facility

    CERN Document Server

    Akerib, D S; Bai, X; Bailey, A J; Balajthy, J; Bedikian, S; Bernard, E; Bernstein, A; Bolozdynya, A; Bradley, A; Byram, D; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chapman, J J; Chiller, A A; Chiller, C; Clark, K; Coffey, T; Currie, A; Curioni, A; Dazeley, S; de Viveiros, L; Dobi, A; Dobson, J; Dragowsky, E M; Druszkiewicz, E; Edwards, B; Faham, C H; Fiorucci, S; Flores, C; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C; Hanhardt, M; Hertel, S A; Horn, M; Huang, D Q; Ihm, M; Jacobsen, R G; Kastens, L; Kazkaz, K; Knoche, R; Kyre, S; Lander, R; Larsen, N A; Lee, C; Leonard, D S; Lesko, K T; Lindote, A; Lopes, M I; Lyashenko, A; Malling, D C; Mannino, R; McKinsey, D N; Mei, D -M; Mock, J; Moongweluwan, M; Morad, J; Morii, M; Murphy, A St J; Nehrkorn, C; Nelson, H; Neves, F; Nikkel, J A; Ott, R A; Pangilinan, M; Parker, P D; Pease, E K; Pech, K; Phelps, P; Reichhart, L; Shutt, T; Silva, C; Skulski, W; Sofka, C J; Solovov, V N; Sorensen, P; Stiegler, T; O`Sullivan, K; Sumner, T J; Svoboda, R; Sweany, M; Szydagis, M; Taylor, D; Tennyson, B; Tiedt, D R; Tripathi, M; Uvarov, S; Verbus, J R; Walsh, N; Webb, R; White, J T; White, D; Witherell, M S; Wlasenko, M; Wolfs, F L H; Woods, M; Zhang, C

    2013-01-01

    The Large Underground Xenon (LUX) experiment, a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), was cooled and filled in February 2013. We report results of the first WIMP search dataset, taken during the period April to August 2013, presenting the analysis of 85.3 live-days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of $7.6 \\times 10^{-46}$ cm$^{2}$ at a WIMP mass of 33 GeV/c$^2$. We find that the LUX data are in strong disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.

  20. Latest results of the direct dark matter search with the EDELWEISS-2 experiment

    CERN Document Server

    ,

    2010-01-01

    EDELWEISS-2 is a Ge-bolometer experiment located in the underground laboratory Laboratoire Souterrain de Modane (LSM, France). For the second phase of the experiment, the collaboration has developed new cryogenic detectors with an improved background rejection (interleaved electrodes design, Phys. Lett. B681 (2009) 305). A continuous operation of ten of these bolometers at LSM together with an active muon veto shielding has been achieved. First results based on an effective exposure of 144 kg \\dot d taken in 2009 have been published recently (Phys. Lett. B687 (2010) 29), the acquired data set has since then been doubled. The already published data correspond to an improvement in sensitivity of about 15 compared to EDELWEISS-1. We present and discuss the latest bolometer data including the identification of muon-induced background events and special measurements of muon-induced neutrons in LSM.

  1. Reading That Matters : A Literature Review on Meaningful Reading Experiences in the EFL Classroom

    OpenAIRE

    Henriksson, Martina

    2015-01-01

    This thesis is a literature review on literature reading in the English as a Foreign Language (EFL) and the English as a Second Language (ESL) classroom, of mainly upper secondary schools. The underlying objective for this work is that meaningful reading experiences can have a positive impact on a developing young individual on his or her way into adulthood. The aim of this thesis is to explore what theories and methods are used when trying to create prerequisites for meaningful reading exper...

  2. Representational Momentum for the Human Body: Awkwardness Matters, Experience Does Not

    OpenAIRE

    Wilson, Margaret; Lancaster, Jessy; Emmorey, Karen

    2010-01-01

    Perception of the human body appears to involve predictive simulations that project forward to track unfolding body-motion events. Here we use representational momentum (RM) to investigate whether implicit knowledge of a learned arbitrary system of body movement such as sign language influences this prediction process, and how this compares to implicit knowledge of biomechanics. Experiment 1 showed greater RM for sign language stimuli in the correct direction of the sign than in the reverse d...

  3. The Aesthetic Experience of the Literary Artwork: A Matter of Form and Content?

    OpenAIRE

    Verheyen, Leen

    2015-01-01

    Ever since the introduction of aesthetics in philosophy, the literary arts have posed a challenge to common notions of aesthetic experience. In this paper, I will focus on the problems that arise when a formalist approach to aesthetics is confronted with literature. My main target is Peter Kivy's ‘essay in literary aesthetics’ Once-Told Tales, in which Kivy defends formalism and concludes from this approach that literature is a non-aesthetic art form. Contrary to Kivy, I will claim that we ha...

  4. Size matter! A choice architectural field experiment in reducing food waste

    OpenAIRE

    Guldborg Hansen, Pelle; Maaløe Jespersen, Andreas; Skov, Laurits Rohden

    2015-01-01

    Objectives We examined how a reduction in plate size would affect the amount of food waste from leftovers in a field experiment at a standing lunch for 220 CEOs. Methods A standing lunch for 220 CEOs in the Danish Opera House was arranged to feature two identical buffets with plates of two different sizes. One buffet featured standard sized plates that served as control (standard size as provided by the caterer, 27cm). A second buffet featured smaller sized plates (24cm) that served as the in...

  5. First results from the LUX dark matter experiment at the Sanford underground research facility.

    Science.gov (United States)

    Akerib, D S; Araújo, H M; Bai, X; Bailey, A J; Balajthy, J; Bedikian, S; Bernard, E; Bernstein, A; Bolozdynya, A; Bradley, A; Byram, D; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chapman, J J; Chiller, A A; Chiller, C; Clark, K; Coffey, T; Currie, A; Curioni, A; Dazeley, S; de Viveiros, L; Dobi, A; Dobson, J; Dragowsky, E M; Druszkiewicz, E; Edwards, B; Faham, C H; Fiorucci, S; Flores, C; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C; Hanhardt, M; Hertel, S A; Horn, M; Huang, D Q; Ihm, M; Jacobsen, R G; Kastens, L; Kazkaz, K; Knoche, R; Kyre, S; Lander, R; Larsen, N A; Lee, C; Leonard, D S; Lesko, K T; Lindote, A; Lopes, M I; Lyashenko, A; Malling, D C; Mannino, R; McKinsey, D N; Mei, D-M; Mock, J; Moongweluwan, M; Morad, J; Morii, M; Murphy, A St J; Nehrkorn, C; Nelson, H; Neves, F; Nikkel, J A; Ott, R A; Pangilinan, M; Parker, P D; Pease, E K; Pech, K; Phelps, P; Reichhart, L; Shutt, T; Silva, C; Skulski, W; Sofka, C J; Solovov, V N; Sorensen, P; Stiegler, T; O'Sullivan, K; Sumner, T J; Svoboda, R; Sweany, M; Szydagis, M; Taylor, D; Tennyson, B; Tiedt, D R; Tripathi, M; Uvarov, S; Verbus, J R; Walsh, N; Webb, R; White, J T; White, D; Witherell, M S; Wlasenko, M; Wolfs, F L H; Woods, M; Zhang, C

    2014-03-07

    The Large Underground Xenon (LUX) experiment is a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota). The LUX cryostat was filled for the first time in the underground laboratory in February 2013. We report results of the first WIMP search data set, taken during the period from April to August 2013, presenting the analysis of 85.3 live days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6 × 10(-46) cm(2) at a WIMP mass of 33 GeV/c(2). We find that the LUX data are in disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.

  6. Novelty vs. familiarity principles in preference decisions: Task-context of past experience matters

    Directory of Open Access Journals (Sweden)

    Hsin-I eLiao

    2011-03-01

    Full Text Available Our preferences are shaped by past experience in many ways, but a systematic understanding of the factors is yet to be achieved. For example, studies of the mere exposure effect show that experience with an item leads to increased liking (familiarity preference, but the exact opposite tendency is found in other studies utilizing dishabituation (novelty preference. Recently, it has been found that image category affects whether familiarity or novelty preference emerges from repeated stimulus exposure (Park, Shimojo, and Shimojo, PNAS 2010. Faces elicited familiarity preference, but natural scenes elicited novelty preference. In their task, preference judgments were made throughout all exposures, raising the question of whether the task-context during exposure was involved. We adapt their paradigm, testing if passive exposure or objective judgment task-contexts lead to different results. Results showed that after passive viewing, familiar faces were preferred, but no preference bias in either direction was found with natural scenes, or with geometric figures (control. After exposure during the objective judgment task, familiar faces were preferred, novel natural scenes were preferred, and no preference bias was found with geometric figures. The overall results replicate the segregation of preference biases across object categories and suggest that the preference for familiar faces and novel natural scenes are modulated by task-context memory at different processing levels or selection involvement. Possible underlying mechanisms of the two types of preferences are discussed.

  7. Early experiences matter: lasting effect of concentrated disadvantage on children's language and cognitive outcomes.

    Science.gov (United States)

    Lloyd, Jennifer E V; Li, Leah; Hertzman, Clyde

    2010-03-01

    A small but provocative literature suggests that neighbourhood socioeconomic conditions experienced by children early in life influence a variety of health and developmental outcomes later in life. We contribute to this literature by testing the degree to which neighbourhood socioeconomic conditions that children experience in Kindergarten influence their later language and cognitive outcomes in early adolescence, over and above current neighbourhood context and various child-level covariates including scores on a Kindergarten measure of school readiness. Cross-classified random effects modelling (CCREM) analyses were performed on a study population of 2648 urban children residing throughout the province of British Columbia, Canada, who were followed longitudinally from Kindergarten (age 5/6) to Grade 7 (age 12/13). Findings demonstrate that neighbourhood concentrated disadvantage experienced during Kindergarten has a durable, negative effect on children's reading comprehension outcomes seven years later-providing evidence that early social contextual experiences play a critical role in the lives of children. Possible explanations and future directions are discussed.

  8. Does Choice of Multicriteria Method Matter? An Experiment in Water Resources Planning

    Science.gov (United States)

    Hobbs, Benjamin F.; Chankong, Vira; Hamadeh, Wael; Stakhiv, Eugene Z.

    1992-07-01

    Many multiple criteria decision making methods have been proposed and applied to water planning. Their purpose is to provide information on tradeoffs among objectives and to help users articulate value judgments in a systematic, coherent, and documentable manner. The wide variety of available techniques confuses potential users, causing inappropriate matching of methods with problems. Experiments in which water planners apply more than one multicriteria procedure to realistic problems can help dispel this confusion by testing method appropriateness, ease of use, and validity. We summarize one such experiment where U.S. Army Corps of Engineers personnel used several methods to screen urban water supply plans. The methods evaluated include goal programming, ELECTRE I, additive value functions, multiplicative utility functions, and three techniques for choosing weights (direct rating, indifference tradeoff, and the analytical hierarchy process). Among the conclusions we reach are the following. First, experienced planners generally prefer simpler, more transparent methods. Additive value functions are favored. Yet none of the methods are endorsed by a majority of the participants; many preferred to use no formal method at all. Second, there is strong evidence that rating, the most commonly applied weight selection method, is likely to lead to weights that fail to represent the trade-offs that users are willing to make among criteria. Finally, we show that decisions can be as or more sensitive to the method used as to which person applies it. Therefore, if who chooses is important, then so too is how a choice is made.

  9. Development of a super-resolution optical microscope for directional dark matter search experiment

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrov, A., E-mail: andrey.alexandrov@na.infn.it [INFN - Napoli, I-80125 Napoli (Italy); LPI - Lebedev Physical Institute of the Russian Academy of Sciences, RUS-119991 Moscow (Russian Federation); Asada, T. [Nagoya University, J-464-8602 Nagoya (Japan); Consiglio, L.; D' Ambrosio, N. [INFN - Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy); De Lellis, G. [INFN - Napoli, I-80125 Napoli (Italy); University of Naples, I-80125 Napoli (Italy); Di Crescenzo, A. [INFN - Napoli, I-80125 Napoli (Italy); Di Marco, N. [INFN - Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy); Furuya, S.; Hakamata, K.; Ishikawa, M.; Katsuragawa, T.; Kuwabara, K.; Machii, S.; Naka, T. [Nagoya University, J-464-8602 Nagoya (Japan); Pupilli, F. [INFN - Laboratori Nazionali di Frascati, I-00044 Frascati (RM) (Italy); Sirignano, C. [University of Padova and INFN, Padova (PD), 35131 Italy (Italy); Tawara, Y. [Nagoya University, J-464-8602 Nagoya (Japan); Tioukov, V. [INFN - Napoli, I-80125 Napoli (Italy); Umemoto, A.; Yoshimoto, M. [Nagoya University, J-464-8602 Nagoya (Japan)

    2016-07-11

    Nuclear emulsion is a perfect choice for a detector for directional DM search because of its high density and excellent position accuracy. The minimal detectable track length of a recoil nucleus in emulsion is required to be at least 100 nm, making the resolution of conventional optical microscopes insufficient to resolve them. Here we report about the R&D on a super-resolution optical microscope to be used in future directional DM search experiments with nuclear emulsion as a detector media. The microscope will be fully automatic, will use novel image acquisition and analysis techniques, will achieve the spatial resolution of the order of few tens of nm and will be capable of reconstructing recoil tracks with the length of at least 100 nm with high angular resolution.

  10. Search for chameleon scalar fields with the axion dark matter experiment.

    Science.gov (United States)

    Rybka, G; Hotz, M; Rosenberg, L J; Asztalos, S J; Carosi, G; Hagmann, C; Kinion, D; van Bibber, K; Hoskins, J; Martin, C; Sikivie, P; Tanner, D B; Bradley, R; Clarke, J

    2010-07-30

    Scalar fields with a "chameleon" property, in which the effective particle mass is a function of its local environment, are common to many theories beyond the standard model and could be responsible for dark energy. If these fields couple weakly to the photon, they could be detectable through the afterglow effect of photon-chameleon-photon transitions. The ADMX experiment was used in the first chameleon search with a microwave cavity to set a new limit on scalar chameleon-photon coupling βγ excluding values between 2×10(9) and 5×10(14) for effective chameleon masses between 1.9510 and 1.9525  μeV.

  11. Ethnicity matters for undergraduate majors in challenges, experiences, and perceptions of psychology.

    Science.gov (United States)

    Lott, Bernice; Rogers, Margaret R

    2011-04-01

    In this investigation of a national sample of undergraduate psychology majors, we directly compare the experiences and perceptions of students of color with those of European Americans. Our aim was to identify factors that might contribute to our discipline's educational pipeline, in which the relative lack of ethnic diversity is a recognized problem. We found that students of color and European American majors are similar in a number of ways but also different in others. Students of color are challenged by less encouragement from and interaction with faculty, perceive a lack of respect, and wish to see more attention to diversity in curriculum, research, faculty, and textbooks. It is not surprising that students of color were significantly less satisfied than European Americans with their studies in psychology.

  12. Experience matters: prior exposure to plant toxins enhances diversity of gut microbes in herbivores.

    Science.gov (United States)

    Kohl, Kevin D; Dearing, M D

    2012-09-01

    For decades, ecologists have hypothesised that exposure to plant secondary compounds (PSCs) modifies herbivore-associated microbial community composition. This notion has not been critically evaluated in wild mammalian herbivores on evolutionary timescales. We investigated responses of the microbial communities of two woodrat species (Neotoma bryanti and N. lepida). For each species, we compared experienced populations that independently converged to feed on the same toxic plant (creosote bush, Larrea tridentata) to naïve populations with no exposure to creosote toxins. The addition of dietary PSCs significantly altered gut microbial community structure, and the response was dependent on previous experience. Microbial diversity and relative abundances of several dominant phyla increased in experienced woodrats in response to PSCs; however, opposite effects were observed in naïve woodrats. These differential responses were convergent in experienced populations of both species. We hypothesise that adaptation of the foregut microbiota to creosote PSCs in experienced woodrats drives this differential response.

  13. Experience teaches plants to learn faster and forget slower in environments where it matters.

    Science.gov (United States)

    Gagliano, Monica; Renton, Michael; Depczynski, Martial; Mancuso, Stefano

    2014-05-01

    The nervous system of animals serves the acquisition, memorization and recollection of information. Like animals, plants also acquire a huge amount of information from their environment, yet their capacity to memorize and organize learned behavioral responses has not been demonstrated. In Mimosa pudica-the sensitive plant-the defensive leaf-folding behaviour in response to repeated physical disturbance exhibits clear habituation, suggesting some elementary form of learning. Applying the theory and the analytical methods usually employed in animal learning research, we show that leaf-folding habituation is more pronounced and persistent for plants growing in energetically costly environments. Astonishingly, Mimosa can display the learned response even when left undisturbed in a more favourable environment for a month. This relatively long-lasting learned behavioural change as a result of previous experience matches the persistence of habituation effects observed in many animals.

  14. Using discrete choice experiments to understand preferences for quality of life. Variance-scale heterogeneity matters.

    Science.gov (United States)

    Flynn, Terry Nicholas; Louviere, Jordan J; Peters, Tim J; Coast, Joanna

    2010-06-01

    Health services researchers are increasingly using discrete choice experiments (DCEs) to model a latent variable, be it health, health-related quality of life or utility. Unfortunately it is not widely recognised that failure to model variance heterogeneity correctly leads to bias in the point estimates. This paper compares variance heterogeneity latent class models with traditional multinomial logistic (MNL) regression models. Using the ICECAP-O quality of life instrument which was designed to provide a set of preference-based general quality of life tariffs for the UK population aged 65+, it demonstrates that there is both mean and variance heterogeneity in preferences for quality of life, which covariate-adjusted MNL is incapable of separating. Two policy-relevant mean groups were found: one group that particularly disliked impairments to independence was dominated by females living alone (typically widows). Males who live alone (often widowers) did not display a preference for independence, but instead showed a strong aversion to social isolation, as did older people (of either sex) who lived with a spouse. Approximately 6-10% of respondents can be classified into a third group that often misunderstood the task. Having a qualification of any type and higher quality of life was associated with smaller random component variances. This illustrates how better understanding of random utility theory enables richer inferences to be drawn from discrete choice experiments. The methods have relevance for all health studies using discrete choice tasks to make inferences about a latent scale, particular QALY valuation exercises that use DCEs, best-worst scaling and ranking tasks. Copyright 2010 Elsevier Ltd. All rights reserved.

  15. Detailed Characterization of Nuclear Recoil Pulse Shape Discrimination in the DarkSide-50 Direct Dark Matter Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Edkins, Erin Elisabeth [Univ. of Hawaii, Honolulu, HI (United States)

    2017-05-01

    While evidence of non-baryonic dark matter has been accumulating for decades, its exact nature continues to remain a mystery. Weakly Interacting Massive Particles (WIMPs) are a well motivated candidate which appear in certain extensions of the Standard Model, independently of dark matter theory. If such particles exist, they should occasionally interact with particles of normal matter, producing a signal which may be detected. The DarkSide-50 direct dark matter experiment aims to detect the energy of recoiling argon atoms due to the elastic scattering of postulated WIMPs. In order to make such a discovery, a clear understanding of both the background and signal region is essential. This understanding requires a careful study of the detector's response to radioactive sources, which in turn requires such sources may be safely introduced into or near the detector volume and reliably removed. The CALibration Insertaion System (CALIS) was designed and built for this purpose in a j oint effort between Fermi National Laboratory and the University of Hawaii. This work describes the design and testing of CALIS, its installation and commissioning at the Laboratori Nazionali del Gran Sasso (LNGS) and the multiple calibration campaigns which have successfully employed it. As nuclear recoils produced by WIMPs are indistinguishable from those produced by neutrons, radiogenic neutrons are both the most dangerous class of background and a vital calibration source for the study of the potential WIMP signal. Prior to the calibration of DarkSide-50 with radioactive neutron sources, the acceptance region was determined by the extrapolation of nuclear recoil data from a separate, dedicated experiment, ScENE, which measured the distribution of the pulse shape discrimination parameter, $f_{90}$, for nuclear recoils of known energies. This work demonstrates the validity of the extrapolation of ScENE values to DarkSide-50, by direct comparison of the $f_{90}$ distributio n of nuclear

  16. Neutron background at the Canfranc Underground Laboratory and its contribution to the IGEX-DM dark matter experiment

    CERN Document Server

    Carmona, J M; García, E; Irastorza, I G; Luzón, G; Morales, A; Morales, J; De Solorzano, A O; Puimedón, J; Sarsa, M L; Villar, J A

    2004-01-01

    A quantitative study of the neutron environment in the Canfranc Underground Laboratory has been performed. The analysis is based on a complete set of simulations and, particularly, it is focused on the IGEX-DM dark matter experiment. The simulations are compared to the IGEX-DM low energy data obtained with different shielding conditions. The results of the study allow us to conclude, with respect to the IGEX-DM background, that the main neutron population, coming from radioactivity from the surrounding rock, is practically eliminated after the implementation of a suitable neutron shielding. The remaining neutron background (muon-induced neutrons in the shielding and in the rock) is substantially below the present background level thanks to the muon veto system. In addition, the present analysis gives us a further insight on the effect of neutrons in other current and future experiments at the Canfranc Underground Laboratory. The comparison of simulations with the body of data available has allowed to set the ...

  17. Dark matter scattering on electrons: Accurate calculations of atomic excitations and implications for the DAMA and XENON experiments

    Science.gov (United States)

    Roberts, Benjamin; Dzuba, Vladimir; Flambaum, Victor; Gribakin, Gleb; Pospelov, Maxim; Stadnik, Yevgeny

    2017-01-01

    Atoms can become ionised during the scattering of a slow, heavy particle off a bound electron. Such an interaction involving leptophilic WIMP dark matter is a potential explanation for the anomalous 9 sigma annual modulation in the DAMA direct detection experiment. We show that due to non-analytic, cusp-like behavior of Coulomb functions close to the nucleus leads to an effective atomic structure enhancement. Crucially, we also show that electron relativistic effects are important. With this in mind, we perform high-accuracy relativistic calculations of atomic ionisation. We scan the parameter space: the DM mass, the mediator mass, and the effective coupling strength, to determine if there is any region that could potentially explain the DAMA signal. While we find that the modulation fraction of all events with energy deposition above 2 keV in NaI can be quite significant, reaching 50%, the relevant parts of the parameter space are excluded by the XENON10 and XENON100 experiments.

  18. Status and Early Results from the Axion Dark Matter eXperiment - High Frequency (ADMX-HF)

    Science.gov (United States)

    Lewis, Samantha; ADMX-HF Collaboration

    2016-03-01

    The axion was originally proposed as a solution to the Strong-CP problem of the Standard Model. A sufficiently light axion (1 - 1000 μ eV) also represents an excellent cold dark matter candidate. Such axions may be detected by their resonant conversion to photons in a high- Q microwave cavity permeated by a strong magnetic field. Previous experiments have probed the first decade in mass using this method. ADMX-HF was designed and built as an innovation test-bed and a data pathfinder for the second decade in mass range. The experiment, initially configured with a 9-tesla magnet, dilution refrigerator, 2-liter tunable copper cavity, and a Josephson Parametric Amplifier, is now operational with a system noise temperature approximately twice the Standard Quantum Limit. Preliminary data in the 25 μ eV range (on the order of 6 GHz in resonant frequency) will be presented, as well as an overview of ongoing R&D on new cavity and amplifier technologies that will be validated in situ within the next few years. This work was supported by the NSF, under Grants PHY-1067242 and PHY-1306729, the US DOE under Contract DE-AC52-07NA27344, and an award from the Heising-Simons Foundation.

  19. 'Trust and teamwork matter': community health workers' experiences in integrated service delivery in India.

    Science.gov (United States)

    Mishra, Arima

    2014-01-01

    A comprehensive and integrated approach to strengthen primary health care has been the major thrust of the National Rural Health Mission (NRHM) that was launched in 2005 to revamp India's rural public health system. Though the logic of horizontal and integrated health care to strengthen health systems has long been acknowledged at policy level, empirical evidence on how such integration operates is rare. Based on recent (2011-2012) ethnographic fieldwork in Odisha, India, this article discusses community health workers' experiences in integrated service delivery through village-level outreach sessions within the NRHM. It shows that for health workers, the notion of integration goes well beyond a technical lens of mixing different health services. Crucially, they perceive 'teamwork' and 'building trust with the community' (beyond trust in health services) to be critical components of their practice. However, the comprehensive NRHM primary health care ideology - which the health workers espouse - is in constant tension with the exigencies of narrow indicators of health system performance. Our ethnography shows how monitoring mechanisms, the institutionalised privileging of statistical evidence over field-based knowledge and the highly hierarchical health bureaucratic structure that rests on top-down communications mitigate efforts towards sustainable health system integration.

  20. Does substrate coarseness matter for foraging ants? An experiment with Lasius niger (Hymenoptera; Formicidae).

    Science.gov (United States)

    Bernadou, Abel; Fourcassié, Vincent

    2008-03-01

    We investigated whether workers of the ant species Lasius niger are able to sense and discriminate the coarseness of the substrate on which they walk. First, we studied the way in which substrate coarseness affects the ants' locomotory behaviour. Second, we investigated the spontaneous preference of ants for substrates of different coarseness. And third, we tested with a differential conditioning procedure the ants' capacity to learn to associate a given coarseness with a food reward. The locomotory behaviour of ants differed according to substrate coarseness: ants moved significantly faster and had more sinuous trajectories on a fine than on a coarse substrate. No spontaneous preference for a substrate of a given coarseness was observed and, even after 20 successive conditioning trials, there was little evidence of the effect of experience on substrate coarseness discrimination. Overall however, ants trained on fine sand made significantly more correct choice than those trained on coarse sand. We discuss these results and argue that in L. niger substrate coarseness may be more important at the collective level, by interacting with the chemical properties of the pheromone trail used in mass recruitment to food source, than at the individual level.

  1. Accounting for Attribute-Level Non-Attendance in a Health Choice Experiment: Does it Matter?

    Science.gov (United States)

    Erdem, Seda; Campbell, Danny; Hole, Arne Risa

    2015-07-01

    An extensive literature has established that it is common for respondents to ignore attributes of the alternatives within choice experiments. In most of the studies on attribute non-attendance, it is assumed that respondents consciously (or unconsciously) ignore one or more attributes of the alternatives, regardless of their levels. In this paper, we present a new line of enquiry and approach for modelling non-attendance in the context of investigating preferences for health service innovations. This approach recognises that non-attendance may not just be associated with attributes but may also apply to the attribute's levels. Our results show that respondents process each level of an attribute differently: while attending to the attribute, they ignore a subset of the attribute's levels. In such cases, the usual approach of assuming that respondents either attend to the attribute or not, irrespective of its levels, is erroneous and could lead to misguided policy recommendations. Our results indicate that allowing for attribute-level non-attendance leads to substantial improvements in the model fit and has an impact on estimated marginal willingness to pay and choice predictions.

  2. Early experiences matter: a review of the effects of prenatal environment on offspring characteristics in poultry.

    Science.gov (United States)

    Dixon, L M; Sparks, N H C; Rutherford, K M D

    2016-03-01

    Early life experiences can be important in determining offspring phenotypes and may influence interaction with the environment and hence health, welfare, and productivity. The prenatal environment of poultry can be divided into the pre-lay environment and the egg storage/incubation environment, both of which can affect offspring outcomes. The ability to separate maternal and egg/incubation effects makes birds well suited to this type of research. There are many factors, including feeding and nutrition, environmental conditions, husbandry practices, housing system, social environment, infectious environment, and maternal health status, that can influence both the health and performance and behavior and cognition of the offspring. There are some aspects of the environments that can be changed to produce beneficial effects in the offspring, like addition of certain additives to feed or short changes in incubation temperatures, while other aspects should be avoided to reduce negative effects, such as unpredictable feeding and lighting regimens. Measures of offspring characteristics may prove to be a useful method of assessing parent stock welfare if known stressors result in predictable offspring outcomes. This has the advantage of assessing the parent environment without interfering with the animals and possibly affecting their responses and could lead to improved welfare for the animals.

  3. Family matters: how mothers of adolescent parents experience adolescent pregnancy and parenting.

    Science.gov (United States)

    Dallas, Constance

    2004-01-01

    Family support has been demonstrated to be essential for successful long-term outcomes of low-income, African American adolescent mothers and their children [Apfel, N., & Seitz, V. (1996). Urban girls: Resisting stereotypes, creating identities. NY: New York University Press]. Family support may also be essential for the continued paternal involvement of unmarried, low-income, African American adolescent fathers. Twenty mothers of unmarried, low-income, African American adolescent parents were individually interviewed for this qualitative study to describe the experiences of paternal grandmothers (mothers of adolescent fathers) and maternal grandmothers (mothers of adolescent mothers) during transition to fatherhood for unmarried, low-income, African American adolescent fathers. Findings are presented according to the six factors of transition conditions from the nursing model of transitions [Schumacher, K., & Meleis, A. I. (1994). Image, 26, 119-127]: meanings, expectations, level of knowledge and skill, the environment, level of planning, and emotional and physical well-being. Findings indicate that transition to parenthood and grandparenthood is often abrupt and complicated for unmarried, low-income, African American adolescent parents and their families. Paternal and maternal grandmothers continue to act as primary parents for their adolescents while compensating for the lack of skills and attributes for the adolescents' children. Findings from this study can be used to design developmentally and culturally appropriate health care interventions that can support these families during this complex process.

  4. Assessment of backgrounds of the ANAIS experiment for dark matter direct detection

    CERN Document Server

    Amare, J; Cuesta, C; Garcia, E; Martinez, M; Olivan, M A; Ortigoza, Y; de Solorzano, A Ortiz; Puimedon, J; Sarsa, M L; Villar, J A; Villar, P

    2016-01-01

    A large effort has been carried out to characterize the background of sodium iodide crystals within the ANAIS (Annual modulation with NaI Scintillators) project. In this paper, the background models developed for three 12.5-kg NaI(Tl) detectors produced by Alpha Spectra Inc. and operated at the Canfranc Underground Laboratory are presented together with an evaluation of the background prospects for the full experiment. Measured spectra from threshold to high energy in different conditions are well described by the models based on quantified activities. At the region of interest, crystal bulk contamination is the dominant background source. Contributions from 210Pb, 40K, 22Na and 3H are the most relevant. Those from 40K and 22Na could be efficiently suppressed thanks to anticoincidence operation in a crystals matrix or inside a Liquid Scintillator Veto (LSV), while that from 210Pb has been reduced by improving crystal production methods and 3H production could be reduced by shielding against cosmic rays during...

  5. Assessment of backgrounds of the ANAIS experiment for dark matter direct detection

    Energy Technology Data Exchange (ETDEWEB)

    Amare, J.; Cebrian, S.; Garcia, E.; Olivan, M.A.; Ortigoza, Y.; Ortiz de Solorzano, A.; Puimedon, J.; Sarsa, M.L.; Villar, J.A.; Villar, P. [Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Zaragoza (Spain); Laboratorio Subterraneo de Canfranc, Huesca (Spain); Cuesta, C. [Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Zaragoza (Spain); Laboratorio Subterraneo de Canfranc, Huesca (Spain); University of Washington, Department of Physics, Center for Experimental Nuclear Physics and Astrophysics, Seattle, WA (United States); Martinez, M. [Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Zaragoza (Spain); Laboratorio Subterraneo de Canfranc, Huesca (Spain); Universita di Roma La Sapienza, Rome (Italy)

    2016-08-15

    A large effort has been carried out to characterize the background of sodium iodide crystals within the Annual modulation with NaI Scintillators (ANAIS) project. In this paper, the background models developed for three 12.5 kg NaI(Tl) scintillators produced by Alpha Spectra Inc. and operated at the Canfranc Underground Laboratory are presented together with an evaluation of the background prospects for the full experiment. Measured spectra from threshold to high energy in different conditions are well described by the models based on quantified activities. At the region of interest, crystal bulk contamination is the dominant background source. Contributions from {sup 210}Pb, {sup 40}K, {sup 22}Na and {sup 3}H are the most relevant. Those from {sup 40}K and {sup 22}Na could be efficiently suppressed thanks to anticoincidence operation in a crystals matrix or inside a liquid scintillator veto (LSV), while that from {sup 210}Pb has been reduced by improving crystal production methods and {sup 3}H production could be reduced by shielding against cosmic rays during production. Assuming the activities of the last characterized detector, for nine crystals with a total mass of 112.5 kg the expected background rate is 2.5 counts/(keV kg day) in the region from 1 to 4 keV, which could be reduced at 1.4 counts/(keV kg day) by using a LSV. (orig.)

  6. Direct searches for non-baryonic dark matter; Experiences de detection directe de la matiere sombre non baryonique

    Energy Technology Data Exchange (ETDEWEB)

    Di Stefano, Philippe E. [Max-Planck-Institut fuer Physik, Munich (Germany)]. E-mail: distefano@mppmu.mpg.de

    2001-10-01

    Since the mid-1980s, non-accelerator particle physics experiments have been searching for weakly interacting massive particles which could solve the dark matter enigma first pointed out some 70 years ago. The low event rate and energies expected pose a formidable experimental challenge. The first detectors were ionization devices, soon followed by scintillation detectors able to reject a small portion of the photon and electron radioactive backgrounds. The performance of these early generations of detectors has now been matched by new cryogenic detectors in which a simultaneous reading of phonons and charge allows a very efficient rejection of the background. These devices, along with recently developed simultaneous phonon and scintillation techniques could provide cryogenic devices with a decisive advantage. (author) [French] La question astrophysique de la matiere sombre, posee dans les annees trente, attire depuis une quinzaine d'annees des experiences de physique des particules hors accelerateur tentant d'y repondre par la mise en evidence de particules lourdes et interagissant faiblement. Le faible taux et la basse energie des evenements attendus rendent la tache ardue. Les premiers detecteurs employes furent a ionisation, puis a scintillation, ceux-ci disposant d'une methode rudimentaire pour rejeter le fond electromagnetique. Ces deux premieres generations d'experiences massives sont aujourd'hui rattrapees par des nouveaux detecteurs cryogeniques associant une mesure de l'ionisation a un signal phonons, qui permettent de rejeter le fond electromagnetique tres efficacement. Ces dispositifs, et de recents developpements de mesure simultanee de scintillation et de phonons, pourraient donner l'avantage aux detecteurs cryogeniques. (author)

  7. D-D Neutron Generator Calibrations and Hardware in the LUX-ZEPLIN Dark Matter Search Experiment

    Science.gov (United States)

    Taylor, Will; Lux-Zeplin Collaboration

    2016-03-01

    The LUX-ZEPLIN (LZ) dark matter search experiment will be a two-phase liquid/gas xenon time projection chamber with 7 tonnes of active liquid xenon (LXe) located at the 4850 ft level of the Sanford Underground Research Facility in Lead, SD. LZ will utilize an in-situ, absolute calibration of nuclear recoils (NR) in LXe using mono-energetic 2.45 MeV neutrons produced by a D-D neutron generator. This technique was used in the LUX detector to measured the NR charge yield in LXe (Qy) to 0.7 keV recoil energy and the NR light yield in LXe (Ly) to recoil energies of 1.1 keV - both of which were the lowest energy measurements achieved in the field. These absolute, ultra-low energy calibrations of the NR signal yields in LXe provide clear measurements of the detector response used for the WIMP search analysis. The improvements made for LZ will include shorter neutron pulse times, multiple neutron conduit configurations, and lower energy neutrons. The upgrades allow for even lower energy measurements of the nuclear recoil response in LXe and an independent measurement of Ly, as well as providing less uncertainty in energy reconstruction. In addition to discussing the physics of the neutron calibrations, I will describe the hardware systems used to implement them.

  8. Radiation hardness investigation of avalanche photodiodes for the Projectile Spectator Detector readout at the Compressed Baryonic Matter experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kushpil, Vasilij [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež (Czech Republic); Mikhaylov, Vasily, E-mail: mikhaylov@ujf.cas.cz [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež (Czech Republic); Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Prague (Czech Republic); Kushpil, Svetlana; Tlustý, Pavel; Svoboda, Ondrej; Kugler, Andrej [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež (Czech Republic)

    2015-07-01

    In this paper, we discuss results of avalanche photodiodes radiation tests for Projectile Spectator Detector at future Compressed Baryonic Matter experiment. The tests were carried out in Nuclear Physics Institute of ASCR in Řež using the cyclotron facility. Secondary neutron beam was used for irradiation because the main radiation damage in the Projectile Spectator Detector is caused by neutrons. Two types of the avalanche photodiodes from Zecotek and Ketek manufacturers were investigated. Special attention was given to the noise investigation and self-annealing after the irradiation. We have irradiated two Ketek PM3375 diodes with equivalent dose for 1 MeV neutrons equal to 2.5±0.2×10{sup 12} n/cm{sup 2}, and single Zecotek MAPD-3N diode with equivalent dose for 1 MeV neutrons equal to 3.4±0.2×10{sup 12} n/cm{sup 2}. All the types of the diodes have shown an increasing level of the noise after the irradiation. From that we can conclude that those avalanche photodiodes are not able to detect single photons anymore due to high noise levels.

  9. Dark Matter Detection in Space

    OpenAIRE

    Feng, Jonathan L.

    2004-01-01

    I review prospects for detecting dark matter in space-based experiments, with an emphasis on recent developments. I propose the ``Martha Stewart criterion'' for identifying dark matter candidates that are particularly worth investigation and focus on three that satisfy it: neutralino dark matter, Kaluza-Klein dark matter, and superWIMP gravitino dark matter.

  10. Current Issues in Finite-T Density-Functional Theory and Warm-Correlated Matter

    Directory of Open Access Journals (Sweden)

    M. W. C. Dharma-wardana

    2016-03-01

    Full Text Available Finite-temperature density functional theory (DFT has become of topical interest, partly due to the increasing ability to create novel states of warm-correlated matter (WCM.Warm-dense matter (WDM, ultra-fast matter (UFM, and high-energy density matter (HEDM may all be regarded as subclasses of WCM. Strong electron-electron, ion-ion and electron-ion correlation effects and partial degeneracies are found in these systems where the electron temperature Te is comparable to the electron Fermi energy EF. Thus, many electrons are in continuum states which are partially occupied. The ion subsystem may be solid, liquid or plasma, with many states of ionization with ionic charge Zj. Quasi-equilibria with the ion temperature Ti ≠ Te are common. The ion subsystem in WCM can no longer be treated as a passive “external potential”, as is customary in T = 0 DFT dominated by solid-state theory or quantum chemistry. Many basic questions arise in trying to implement DFT for WCM. Hohenberg-Kohn-Mermin theory can be adapted for treating these systems if suitable finite-T exchange-correlation (XC functionals can be constructed. They are functionals of both the one-body electron density ne and the one-body ion densities ρj. Here, j counts many species of nuclei or charge states. A method of approximately but accurately mapping the quantum electrons to a classical Coulomb gas enables one to treat electron-ion systems entirely classically at any temperature and arbitrary spin polarization, using exchange-correlation effects calculated in situ, directly from the pair-distribution functions. This eliminates the need for any XC-functionals. This classical map has been used to calculate the equation of state of WDM systems, and construct a finite-T XC functional that is found to be in close agreement with recent quantum path-integral simulation data. In this review, current developments and concerns in finite-T DFT, especially in the context of non-relativistic warm-dense

  11. TLC: The Experience Matters

    Science.gov (United States)

    Steele, William; Kuban, Caelan

    2012-01-01

    Only as adults witness the world experienced by traumatized children can they develop appropriate interventions that lead to healing and resilience. This article highlights the philosophy and programs of the National Institute for Trauma and Loss in Children. The National Institute for Trauma and Loss in Children (TLC) was founded in 1990 by…

  12. Does direct experience matter?

    DEFF Research Database (Denmark)

    Miralles, Francesc; Giones, Ferran; Gozun, Brian

    2017-01-01

    Entrepreneurial behavior research has used intention models to explain how an individual’s beliefs shape the attitudes and motivations that influence entrepreneurial intention. Nevertheless, as entrepreneurship promotion initiatives become global, it becomes relevant to explore the consequences o...

  13. TLC: The Experience Matters

    Science.gov (United States)

    Steele, William; Kuban, Caelan

    2012-01-01

    Only as adults witness the world experienced by traumatized children can they develop appropriate interventions that lead to healing and resilience. This article highlights the philosophy and programs of the National Institute for Trauma and Loss in Children. The National Institute for Trauma and Loss in Children (TLC) was founded in 1990 by…

  14. Status of Dark Matter Indirect Detection and Collider Detection Experiments%暗物质间接探测和对撞机探测实验现状

    Institute of Scientific and Technical Information of China (English)

    姚道新; 余钊焕; 蔡成丰; 王青; 张宏浩; 方锡岩

    2012-01-01

    综述了暗物质间接探测和对撞机探测实验的现状和最新进展,并对现有主要实验的最新结果和限制进行了归纳总结.自2008年以来,宇宙线正负电子谱的反常超出被多个实验组相继报道出来.尽管存在一些争议,暗物质效应是这些超出现象的一种自然解释.另一方面,反质子-质子比和γ射线观测结果均未呈现反常信号,这为暗物质的性质给出很强的限制.此外,也可以通过对撞机探测实验上的零信号来限制暗物质性质.在不久的将来,AMS-02和LHC的新数据可能会为暗物质研究提供新的启示.%The current status and recent progress of dark matter indirect detection and collider detection experiments are briefly reviewed. The main results and constraints of new experiments are shown. Since 2008, anomalous excesses of cosmic-ray electron and positron spectra have been reported by several ex periment collaborations. Despite of some arguments, these excesses can be explained naturally by dark matter effect. On the other hand, both antiproton to proton ratio and gamma-ray results show no anoma lous signal and give strong constraints on dark matter. Additionally, constraints on dark matter can be derived from the zero signals from collider detection experiments. In the near future, new results of AMS 02 and LHC may give us some inspirations for dark matter researches.

  15. Probing the MSSM explanation of the muon g-2 anomaly in dark matter experiments and at a 100 TeV $pp$ collider

    CERN Document Server

    Kobakhidze, Archil; Wu, Lei

    2016-01-01

    We investigate the prospect of current and future dark matter and collider experiments in probing anomalous magnetic moment of the muon, $(g-2)_\\mu$, within the Minimal Supersymmetric Standard Model (MSSM). Imposing constraints from currently available Higgs data, dark matter relic density, PandaX-II/LUX-2016 experiments and LHC searches for dilepton and tripleton events, we find a range of MSSM parameters with the lightest neutralino $m_{\\widetilde{\\chi}^0_{1}}<800$ GeV and the lightest chargino $m_{\\widetilde{\\chi}^\\pm_{1}}<940$ GeV which can accommodate the measured value of $(g-2)_{\\mu}$ within $2\\sigma$ range. We also observe that a large portion of this parameter space cannot fully account for the observed dark matter abundance (within $3\\sigma$ range) and additional dark matter components beyond MSSM are presumably needed. Further to this we demonstrate that the most of the currently allowed parameter space (except for the compressed region) can be fully probed via searches for trilepton events a...

  16. Dark Matter Results from First 98.7 Days of Data from the PandaX-II Experiment.

    Science.gov (United States)

    Tan, Andi; Xiao, Mengjiao; Cui, Xiangyi; Chen, Xun; Chen, Yunhua; Fang, Deqing; Fu, Changbo; Giboni, Karl; Giuliani, Franco; Gong, Haowei; Guo, Xuyuan; Han, Ke; Hu, Shouyang; Huang, Xingtao; Ji, Xiangdong; Ju, Yonglin; Lei, Siao; Li, Shaoli; Li, Xiaomei; Li, Xinglong; Liang, Hao; Lin, Qing; Liu, Huaxuan; Liu, Jianglai; Lorenzon, Wolfgang; Ma, Yugang; Mao, Yajun; Ni, Kaixuan; Ren, Xiangxiang; Schubnell, Michael; Shen, Manbin; Shi, Fang; Wang, Hongwei; Wang, Jimin; Wang, Meng; Wang, Qiuhong; Wang, Siguang; Wang, Xuming; Wang, Zhou; Wu, Shiyong; Xiao, Xiang; Xie, Pengwei; Yan, Binbin; Yang, Yong; Yue, Jianfeng; Zeng, Xionghui; Zhang, Hongguang; Zhang, Hua; Zhang, Huanqiao; Zhang, Tao; Zhao, Li; Zhou, Jing; Zhou, Ning; Zhou, Xiaopeng

    2016-09-16

    We report the weakly interacting massive particle (WIMP) dark matter search results using the first physics-run data of the PandaX-II 500 kg liquid xenon dual-phase time-projection chamber, operating at the China JinPing underground laboratory. No dark matter candidate is identified above background. In combination with the data set during the commissioning run, with a total exposure of 3.3×10^{4}  kg day, the most stringent limit to the spin-independent interaction between the ordinary and WIMP dark matter is set for a range of dark matter mass between 5 and 1000  GeV/c^{2}. The best upper limit on the scattering cross section is found 2.5×10^{-46}  cm^{2} for the WIMP mass 40  GeV/c^{2} at 90% confidence level.

  17. Changes of Organic Matter, N, P and K Content of Soils in Red Soil Areas Under Long-Term Experiment

    Institute of Scientific and Technical Information of China (English)

    JIANG Duan-sheng; ZENG Xi-bai; GAO Ju-sheng; LI Lian-fang

    2008-01-01

    The content of organic matter (OM), nitrogen (N), phosphorus (P), and potassium (K) in the three selected soils, including Calcaric Purpli-Orthic Primosols (purple sand-shale parent material), Dystric Turbi-Anthric Primosols (quaternary red clay parent material) and Typic Udi-Sandic Primosols (granite parent material) were studied under a long-term experiment by using crop straw and inorganic fertilizers at the Hunan Red Soil Experiment Station of Chinese Academy of Agricultural Sciences. The results showed that the contents of OM, N, P and K in the three selected soils increased after 23 years application of crop straw and inorganic fertilizers, but the contents increased much less when crop straw or inorganic fertilizers was applied alone. The nutrient contents in the three soils developed from granite changed more remarkably than those in the soil derived from quaternary red clay and purple sand-shale. It was also found that the contents of OM, N, and P increased slightly in the treatments without applying fertilizers or returning the crop straw to the root bed. Combined application of inorganic fertilizers and crop straw could remarkably increase the contents of OM, alkali- hydrolyzable N and available K, the positive correlation between application of organic fertilizers and increase of OM in soil did not always happened, it provided evidence for the relation between appropriate C/N ratio and accumulation of OM in soil. The increase of nutrient content was influenced by the soil properties. By comparing the contents of nutrient in 0-20 cm depth in the three different soils, it was concluded that the most increases of OM, alkali-hydrolyzable N, and available P were observed in Typic Udi-Sandic Primosols with the average increase by 3.03, 27.38, and 21.73 mg kg-1, respectively. The available K increased in Dystric Turbi-Anthric Primosols with the average increase by 25.82 mg kg-1, while it decreased in Calcaric Purpli-Orthic Primosols and Typic Udi

  18. Organic matter production response to CO2 increase in open subarctic plankton communities: Comparison of six microcosm experiments under iron-limited and -enriched bloom conditions

    Science.gov (United States)

    Yoshimura, Takeshi; Sugie, Koji; Endo, Hisashi; Suzuki, Koji; Nishioka, Jun; Ono, Tsuneo

    2014-12-01

    Increase in seawater pCO2 and the corresponding decrease in pH caused by the increasing atmospheric CO2 concentration (i.e., ocean acidification) may affect organic matter production by phytoplankton communities. Organic matter production forms the basis of marine food webs and plays a crucial role in oceanic CO2 uptake through the biological carbon pump, and hence will potentially affect future marine ecosystem dynamics. However, responses of organic matter production in open ocean plankton ecosystems to CO2 increase have not been fully examined. We conducted on-deck microcosm experiments using high nutrient, low chlorophyll (HNLC) waters in the western subarctic Pacific and oceanic Bering Sea basin in summer 2008 and 2009, respectively, to examine the impacts of elevated CO2 on particulate and dissolved organic matter (i.e., POM and DOM, respectively) production. Iron deficient natural plankton communities were incubated for 7-14 days under multiple CO2 levels with and without iron enrichments (hereafter +Fe and -Fe treatments, respectively). By combining with our previous experiments at two sites, we created a comprehensive dataset on responses of organic matter production to CO2 increase during macronutrient replete conditions in HNLC waters. Significant differences in net particulate organic carbon production among CO2 treatments were observed only in the -Fe treatments, whereas that in net dissolved organic carbon production were mainly observed in the +Fe treatments, suggesting that CO2 may affect different processes depending on the Fe nutritional status. However, impacts of CO2 were not consistent among experiments and were much smaller than the consistent positive effects of Fe enrichment. In contrast, no significant differences among the CO2 treatments were observed for organic carbon partitioning into POM and DOM, and carbon to nitrogen ratio of net produced POM. We conclude that CO2 does not play a primary role, but could have secondary effects on

  19. Deep-sea nematodes actively colonise sediments, irrespective of the presence of a pulse of organic matter: results from an in-situ experiment.

    Directory of Open Access Journals (Sweden)

    Katja Guilini

    Full Text Available A colonisation experiment was performed in situ at 2500 m water depth at the Arctic deep-sea long-term observatory HAUSGARTEN to determine the response of deep-sea nematodes to disturbed, newly available patches, enriched with organic matter. Cylindrical tubes,laterally covered with a 500 µm mesh, were filled with azoic deep-sea sediment and (13C-labelled food sources (diatoms and bacteria. After 10 days of incubation the tubes were analysed for nematode response in terms of colonisation and uptake. Nematodes actively colonised the tubes, however with densities that only accounted for a maximum of 2.13% (51 ind.10 cm(-2 of the ambient nematode assemblages. Densities did not differ according to the presence or absence of organic matter, nor according to the type of organic matter added. The fact that the organic matter did not function as an attractant to nematodes was confirmed by the absence of notable (13C assimilation by the colonising nematodes. Overall, colonisation appears to be a process that yields reproducible abundance and diversity patterns, with certain taxa showing more efficiency. Together with the high variability between the colonising nematode assemblages, this lends experimental support to the existence of a spatio-temporal mosaic that emerges from highly localised, partially stochastic community dynamics.

  20. Phase-space structure in the local dark matter distribution and its signature in direct detection experiments

    NARCIS (Netherlands)

    Vogelsberger, Mark; Helmi, Amina; Springel, Volker; White, Simon D. M.; Wang, Jie; Frenk, Carlos S.; Jenkins, Adrian; Ludlow, Aaron; Navarro, Julio F.

    2009-01-01

    We study predictions for dark matter (DM) phase-space structure near the Sun based on high-resolution simulations of six galaxy haloes taken from the Aquarius project. The local DM density distribution is predicted to be remarkably smooth; the density at the Sun differs from the mean over a best-fit

  1. Phase-space structure in the local dark matter distribution and its signature in direct detection experiments

    NARCIS (Netherlands)

    Vogelsberger, Mark; Helmi, Amina; Springel, Volker; White, Simon D. M.; Wang, Jie; Frenk, Carlos S.; Jenkins, Adrian; Ludlow, Aaron; Navarro, Julio F.

    2008-01-01

    We study predictions for dark matter phase-space structure near the Sun based on high-resolution simulations of six galaxy halos taken from the Aquarius Project. The local DM density distribution is predicted to be remarkably smooth; the density at the Sun differs from the mean over a best-fit ellip

  2. First results from the DarkSide-50 dark matter experiment at Laboratori Nazionali del Gran Sasso

    Energy Technology Data Exchange (ETDEWEB)

    Agnes, P.; Alexander, T.; Alton, A.; Arisaka, K.; Back, H. O.; Baldin, B.; Biery, K.; Bonfini, G.; Bossa, M.; Brigatti, A.; Brodsky, J.; Budano, F.; Cadonati, L.; Calaprice, F.; Canci, N.; Candela, A.; Cao, H.; Cariello, M.; Cavalcante, P.; Chavarria, A.; Chepurnov, A.; Cocco, A. G.; Crippa, L.; D' Angelo, D.; D' Incecco, M.; Davini, S.; De Deo, M.; Derbin, A.; Devoto, A.; Di Eusanio, F.; Di Pietro, G.; Edkins, E.; Empl, A.; Fan, A.; Fiorillo, G.; Fomenko, K.; Forster, G.; Franco, D.; Gabriele, F.; Galbiati, C.; Goretti, A.; Grandi, L.; Gromov, M.; Guan, M. Y.; Guardincerri, Y.; Hackett, B.; Herner, K.; Hungerford, E. V.; Ianni, Al.; Ianni, An.; Jollet, C.; Keeter, K.; Kendziora, C.; Kidner, S.; Kobychev, V.; Koh, G.; Korablev, D.; Korga, G.; Kurlej, A.; Li, P. X.; Loer, B.; Lombardi, P.; Love, C.; Ludhova, L.; Luitz, S.; Ma, Y. Q.; Machulin, I.; Mandarano, A.; Mari, S.; Maricic, J.; Marini, L.; Martoff, C. J.; Meregaglia, A.; Meroni, E.; Meyers, P. D.; Milincic, R.; Montanari, D.; Monte, A.; Montuschi, M.; Monzani, M. E.; Mosteiro, P.; Mount, B.; Muratova, V.; Musico, P.; Nelson, A.; Odrowski, S.; Okounkova, M.; Orsini, M.; Ortica, F.; Pagani, L.; Pallavicini, M.; Pantic, E.; Papp, L.; Parmeggiano, S.; Parsells, R.; Pelczar, K.; Pelliccia, N.; Perasso, S.; Pocar, A.; Pordes, S.; Pugachev, D.; Qian, H.; Randle, K.; Ranucci, G.; Razeto, A.; Reinhold, B.; Renshaw, A.; Romani, A.; Rossi, B.; Rossi, N.; Rountree, S. D.; Sablone, D.; Saggese, P.; Saldanha, R.; Sands, W.; Sangiorgio, S.; Segreto, E.; Semenov, D.; Shields, E.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Stanford, C.; Suvorov, Y.; Tartaglia, R.; Tatarowicz, J.; Testera, G.; Tonazzo, A.; Unzhakov, E.; Vogelaar, R. B.; Wada, M.; Walker, S.; Wang, H.; Wang, Y.; Watson, A.; Westerdale, S.; Wojcik, M.; Wright, A.; Xiang, X.; Xu, J.; Yang, C. G.; Yoo, J.; Zavatarelli, S.; Zec, A.; Zhu, C.; Zuzel, G.

    2015-04-01

    We report the first results of DarkSide-50, a direct search for dark matter operating in the underground Laboratori Nazionali del Gran Sasso (LNGS) and searching for the rare nuclear recoils possibly induced by weakly interacting massive particles (WIMPs). The dark matter detector is a Liquid Argon Time Projection Chamber with a (46.4±0.7) kg active mass, operated inside a 30 t organic liquid scintillator neutron veto, which is in turn installed at the center of a 1 kt water Cherenkov veto for the residual flux of cosmic rays. We report here the null results of a dark matter search for a View the MathML source exposure with an atmospheric argon fill. This is the most sensitive dark matter search performed with an argon target, corresponding to a 90% CL upper limit on the WIMP-nucleon spin-independent cross section of 6.1×10-44 cm2 for a WIMP mass of 100 Gev/c2

  3. First Results from the DarkSide-50 Dark Matter Experiment at Laboratori Nazionali del Gran Sasso

    CERN Document Server

    Agnes, P; Alton, A; Arisaka, K; Back, H O; Baldin, B; Biery, K; Bonfini, G; Bossa, M; Brigatti, A; Brodsky, J; Budano, F; Cadonati, L; Calaprice, F; Canci, N; Candela, A; Cao, H; Cariello, M; Cavalcante, P; Chavarria, A; Chepurnov, A; Cocco, A G; Crippa, L; D'Angelo, D; D'Incecco, M; Davini, S; De Deo, M; Derbin, A; Devoto, A; Di Eusanio, F; Di Pietro, G; Edkins, E; Empl, A; Fan, A; Fiorillo, G; Fomenko, K; Forster, G; Franco, D; Gabriele, F; Galbiati, C; Goretti, A; Grandi, L; Gromov, M; Guan, M Y; Guardincerri, Y; Hackett, B; Herner, K; Hungerford, E V; Ianni, Al; Ianni, An; Jollet, C; Keeter, K; Kendziora, C; Kidner, S; Kobychev, V; Koh, G; Korablev, D; Korga, G; Kurlej, A; Li, P X; Loer, B; Lombardi, P; Love, C; Ludhova, L; Luitz, S; Ma, Y Q; Machulin, I; Mandarano, A; Mari, S; Maricic, J; Marini, L; Martoff, C J; Meregaglia, A; Meroni, E; Meyers, P D; Milincic, R; Montanari, D; Montuschi, M; Monzani, M E; Mosteiro, P; Mount, B; Muratova, V; Musico, P; Nelson, A; Odrowski, S; Okounkova, M; Orsini, M; Ortica, F; Pagani, L; Pallavicini, M; Pantic, E; Papp, L; Parmeggiano, S; Parsells, R; Pelczar, K; Pelliccia, N; Perasso, S; Pocar, A; Pordes, S; Pugachev, D; Qian, H; Randle, K; Ranucci, G; Razeto, A; Reinhold, B; Renshaw, A; Romani, A; Rossi, B; Rossi, N; Rountree, S D; Sablone, D; Saggese, P; Saldanha, R; Sands, W; Sangiorgio, S; Segreto, E; Semenov, D; Shields, E; Skorokhvatov, M; Smirnov, O; Sotnikov, A; Stanford, C; Suvorov, Y; Tartaglia, R; Tatarowicz, J; Testera, G; Tonazzo, A; Unzhakov, E; Vogelaar, R B; Wada, M; Walker, S; Wang, H; Wang, Y; Watson, A; Westerdale, S; Wojcik, M; Wright, A; Xiang, X; Xu, J; Yang, C G; Yoo, J; Zavatarelli, S; Zec, A; Zhu, C; Zuzel, G

    2015-01-01

    We report the first results of DarkSide-50, a direct search for dark matter operating in the underground Laboratori Nazionali del Gran Sasso (LNGS) and searching for the rare nuclear recoils possibly induced by weakly interacting massive particles (WIMPs). The dark matter detector is a Liquid Argon Time Projection Chamber with a (46.4+-0.7) kg active mass, operated inside a 30 t organic liquid scintillator neutron veto, which is in turn installed at the center of a 1 kt water Cherenkov veto for the residual flux of cosmic rays. We report here the null results of a dark matter search for a (1422+-67) kg d exposure with an atmospheric argon fill. This is the most sensitive dark matter search performed with an argon target, corresponding to a 90% CL upper limit on the WIMP-nucleon spin-independent cross section of 6.1x10^-44 cm^2 for a WIMP mass of 100 GeV/c^2.

  4. First results from the DarkSide-50 dark matter experiment at Laboratori Nazionali del Gran Sasso

    Directory of Open Access Journals (Sweden)

    P. Agnes

    2015-04-01

    Full Text Available We report the first results of DarkSide-50, a direct search for dark matter operating in the underground Laboratori Nazionali del Gran Sasso (LNGS and searching for the rare nuclear recoils possibly induced by weakly interacting massive particles (WIMPs. The dark matter detector is a Liquid Argon Time Projection Chamber with a (46.4±0.7 kg active mass, operated inside a 30 t organic liquid scintillator neutron veto, which is in turn installed at the center of a 1 kt water Cherenkov veto for the residual flux of cosmic rays. We report here the null results of a dark matter search for a (1422±67 kgd exposure with an atmospheric argon fill. This is the most sensitive dark matter search performed with an argon target, corresponding to a 90% CL upper limit on the WIMP-nucleon spin-independent cross section of 6.1×10−44 cm2 for a WIMP mass of 100 Gev/c2.

  5. A description of the Galactic Center excess in the Minimal Supersymmetric Standard Model and the Dark Matter signatures for the LHC and direct and indire ct detection experiments

    CERN Document Server

    Caron, Sascha; Hendriks, Luc; de Austri, Roberto Ruiz; Weniger, Christoph

    2015-01-01

    Observations with the Fermi Large Area Telescope (LAT) indicate an excess in gamma rays originating from the center of our Galaxy. A possible explanation for this excess is the annihilation of Dark Matter particles. We have investigated the annihilation of neutralinos as Dark Matter candidates within the phenomenological Minimal Supersymmetric Standard Model (pMSSM). An iterative particle filter approach was used to search for solutions within the pMSSM. We found solutions that are consistent with astroparticle physics and collider experiments, and provide a reasonable fit to the energy spectrum of the excess. The neutralino is a Bino/Higgsino mixture and a mass in the range $84-92$~GeV yielding a Dark Matter relic density $0.06 < \\Omega h^2 <0.13$. These pMSSM solutions make clear forecasts for LHC, direct and indirect DM detection experiments. If the pMSSM explanation of the excess seen by Fermi-LAT is correct, a DM signal might be discovered soon.

  6. Commissioning of the ArDM experiment at the Canfranc underground laboratory: first steps towards a tonne-scale liquid argon time projection chamber for Dark Matter searches

    Science.gov (United States)

    Calvo, J.; Cantini, C.; Crivelli, P.; Daniel, M.; Di Luise, S.; Gendotti, A.; Horikawa, S.; Montes, B.; Mu, W.; Murphy, S.; Natterer, G.; Nguyen, K.; Periale, L.; Quan, Y.; Radics, B.; Regenfus, C.; Romero, L.; Rubbia, A.; Santorelli, R.; Sergiampietri, F.; Viant, T.; Wu, S.

    2017-03-01

    The Argon Dark Matter (ArDM) experiment consists of a liquid argon (LAr) time projection chamber (TPC) sensitive to nuclear recoils, resulting from scattering of hypothetical Weakly Interacting Massive Particles (WIMPs) on argon targets. With an active target mass of 850 kg ArDM represents an important milestone towards developments for large LAr Dark Matter detectors. Here we present the experimental apparatus currently installed underground at the Laboratorio Subterráneo de Canfranc (LSC), Spain. We show data on gaseous or liquid argon targets recorded in 2015 during the commissioning of ArDM in single phase at zero E-field (ArDM Run I). The data confirms the overall good and stable performance of the ArDM tonne-scale LAr detector.

  7. Clinical and neuroimaging findings in children with gray matter heterotopias: A single institution experience of 36 patients.

    Science.gov (United States)

    Hung, Po-Cheng; Wang, Huei-Shyong; Chou, Ming-Liang; Lin, Kuang-Lin; Hsieh, Meng-Ying; Wong, Alex M-C

    2016-09-01

    To describe the clinical spectrum and neuroimaging features of childhood gray matter heterotopias in a single tertiary hospital in Taiwan. We retrospectively reviewed the medical records and magnetic resonance images (MRI) of 36 patients with gray matter heterotopias, 19 females and 17 males, between July 1999 and June 2014. The MRI morphologic findings of gray matter heterotopias were recorded along with the presence of associated cerebral malformations. The clinical, electrophysiological and associated systemic malformation data were also recorded. A total of 36 patients were included in the study. Their ages ranged from 1 month to 18 years with a mean age of 3 years 6 months. According to the location of gray matter heterotopias, patients were classified into two groups: periventricular (26) and band (10). The phenotypic spectrum in our population differed from that described previously. In the periventricular group, additional cerebral malformations were found in 18/26 (69%) and systemic malformations in 14/26 (54%). In the band group, additional cerebral malformations were found in 5/10 (50%) and systemic malformations in 2/10 (20%). The majority of patients had developmental delay and intellectual deficit. Twenty-two patients suffered from epileptic seizures with 12 developing refractory epilepsy. In periventricular heterotopias, the most common associated cerebral malformation was ventriculomegaly, followed by agenesis of corpus callosum. Congenital heart disease was the most common additional systemic malformation. However, the most common associated cerebral malformation was pachygyria in band form. The majority of patients had developmental delay, intellectual deficit, especially in band heterotopias. Copyright © 2016 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  8. Dark Matter

    OpenAIRE

    Einasto, Jaan

    2013-01-01

    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...

  9. Theoretical models for describing longitudinal bunch compression in the neutralized drift compression experiment

    Directory of Open Access Journals (Sweden)

    Adam B. Sefkow

    2006-09-01

    Full Text Available Heavy ion drivers for warm dense matter and heavy ion fusion applications use intense charge bunches which must undergo transverse and longitudinal compression in order to meet the requisite high current densities and short pulse durations desired at the target. The neutralized drift compression experiment (NDCX at the Lawrence Berkeley National Laboratory is used to study the longitudinal neutralized drift compression of a space-charge-dominated ion beam, which occurs due to an imposed longitudinal velocity tilt and subsequent neutralization of the beam’s space charge by background plasma. Reduced theoretical models have been used in order to describe the realistic propagation of an intense charge bunch through the NDCX device. A warm-fluid model is presented as a tractable computational tool for investigating the nonideal effects associated with the experimental acceleration gap geometry and voltage waveform of the induction module, which acts as a means to pulse shape both the velocity and line density profiles. Self-similar drift compression solutions can be realized in order to transversely focus the entire charge bunch to the same focal plane in upcoming simultaneous transverse and longitudinal focusing experiments. A kinetic formalism based on the Vlasov equation has been employed in order to show that the peaks in the experimental current profiles are a result of the fact that only the central portion of the beam contributes effectively to the main compressed pulse. Significant portions of the charge bunch reside in the nonlinearly compressing part of the ion beam because of deviations between the experimental and ideal velocity tilts. Those regions form a pedestal of current around the central peak, thereby decreasing the amount of achievable longitudinal compression and increasing the pulse durations achieved at the focal plane. A hybrid fluid-Vlasov model which retains the advantages of both the fluid and kinetic approaches has been

  10. Characterization and performance of germanium detectors with sub-keV sensitivities for neutrino and dark matter experiments

    Science.gov (United States)

    Soma, A. K.; Singh, M. K.; Singh, L.; Kumar, G. Kiran; Lin, F. K.; Du, Q.; Jiang, H.; Liu, S. K.; Ma, J. L.; Sharma, V.; Wang, L.; Wu, Y. C.; Yang, L. T.; Zhao, W.; Agartioglu, M.; Asryan, G.; Chang, Y. Y.; Chen, J. H.; Chuang, Y. C.; Deniz, M.; Hsu, C. L.; Hsu, Y. H.; Huang, T. R.; Jia, L. P.; Kerman, S.; Li, H. B.; Li, J.; Liao, F. T.; Liao, H. Y.; Lin, C. W.; Lin, S. T.; Marian, V.; Ruan, X. C.; Sevda, B.; Shen, Y. T.; Singh, M. K.; Singh, V.; Sonay, A.; Su, J.; Subrahmanyam, V. S.; Tseng, C. H.; Wang, J. J.; Wong, H. T.; Xu, Y.; Yang, S. W.; Yu, C. X.; Yue, Q.; Zeyrek, M.

    2016-11-01

    Germanium ionization detectors with sensitivities as low as 100 eVee (electron-equivalent energy) open new windows for studies on neutrino and dark matter physics. The relevant physics subjects are summarized. The detectors have to measure physics signals whose amplitude is comparable to that of pedestal electronic noise. To fully exploit this new detector technique, various experimental issues including quenching factors, energy reconstruction and calibration, signal triggering and selection as well as evaluation of their associated efficiencies have to be attended. The efforts and results of a research program to address these challenges are presented.

  11. Active matter

    Science.gov (United States)

    Ramaswamy, Sriram

    2017-05-01

    The study of systems with sustained energy uptake and dissipation at the scale of the constituent particles is an area of central interest in nonequilibrium statistical physics. Identifying such systems as a distinct category—Active matter—unifies our understanding of autonomous collective movement in the living world and in some surprising inanimate imitations. In this article I present the active matter framework, briefly recall some early work, review our recent results on single-particle and collective behaviour, including experiments on active granular monolayers, and discuss new directions for the future.

  12. Experience Matters: The Impact of Doing versus Watching on Infants' Subsequent Perception of Tool-Use Events

    Science.gov (United States)

    Sommerville, Jessica A.; Hildebrand, Elina A.; Crane, Catharyn C.

    2008-01-01

    Prior work suggests that active experience affects infants' understanding of simple actions. The present studies compared the impact of active and observational experience on infants' ability to identify the goal of a novel tool-use event. Infants either received active training and practice in using a cane to retrieve an out-of-reach toy or had…

  13. The origin of dark matter, matter-anti-matter asymmetry, and inflation

    CERN Document Server

    Mazumdar, Anupam

    2011-01-01

    A rapid phase of accelerated expansion in the early universe, known as inflation, dilutes all matter except the vacuum induced quantum fluctuations. These are responsible for seeding the initial perturbations in the baryonic matter, the non-baryonic dark matter and the observed temperature anisotropy in the cosmic microwave background (CMB) radiation. To explain the universe observed today, the end of inflation must also excite a thermal bath filled with baryons, an amount of baryon asymmetry, and dark matter. We review the current understanding of inflation, dark matter, mechanisms for generating matter-anti-matter asymmetry, and the prospects for testing them at ground and space based experiments.

  14. Matter in Extreme Conditions Instrument - Conceptual Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Boyce, R.F.; Boyce, R.M.; Haller, G.; Hastings, J.B.; Hays, G.; Lee, H.J.; /SLAC; Lee, R.W.; /LLNL, Livermore; Nagler, B.; /Rutherford; Scharfenstein, M.; Marsh, D.; White, W.E.; /SLAC

    2009-12-09

    The SLAC National Accelerator Laboratory (SLAC), in collaboration with Argonne National Laboratory (ANL), Lawrence Livermore National Laboratory (LLNL), and the University of California at Los Angeles (UCLA), is constructing a Free-Electron Laser (FEL) research facility. The FEL has already met its performance goals in the wavelength range 1.5 nm - 0.15 nm. This facility, the Linac Coherent Light Source (LCLS), utilizes the SLAC 2-Mile Linear Accelerator (linac) and will produce sub-picosecond pulses of short wavelength X-rays with very high peak brightness and almost complete transverse coherence. The final one-third of the SLAC linac is used as the source of electrons for the LCLS. The high energy electrons are transported across the SLAC Research Yard, into a tunnel which houses a long undulator. In passing through the undulator, the electrons are bunched by the force of their own synchrotron radiation and produce an intense, monochromatic, spatially coherent beam of X-rays. By varying the electron energy, the FEL X-ray wavelength is tunable from 1.5 nm to 0.15 nm. The LCLS includes two experimental halls as well as X-ray optics and infrastructure necessary to create a facility that can be developed for research in a variety of disciplines such as atomic physics, materials science, plasma physics and biosciences. This Conceptual Design Report, the authors believe, confirms the feasibility of designing and constructing an X-ray instrument in order to exploit the unique scientific capability of LCLS by creating extreme conditions and study the behavior of plasma under those controlled conditions. This instrument will address the Office of Science, Fusion Energy Sciences, mission objective related to study of Plasma and Warm Dense Matter as described in the report titled LCLS, the First Experiments, prepared by the LCLS Scientific Advisory Committee (SAC) in September 2000. The technical objective of the LCLS Matter in Extreme Conditions (MEC) Instrument project is

  15. Matter in Extreme Conditions Instrument - Conceptual Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Boyce, R.F.; Boyce, R.M.; Haller, G.; Hastings, J.B.; Hays, G.; Lee, H.J.; /SLAC; Lee, R.W.; /LLNL, Livermore; Nagler, B.; /Rutherford; Scharfenstein, M.; Marsh, D.; White, W.E.; /SLAC

    2009-12-09

    The SLAC National Accelerator Laboratory (SLAC), in collaboration with Argonne National Laboratory (ANL), Lawrence Livermore National Laboratory (LLNL), and the University of California at Los Angeles (UCLA), is constructing a Free-Electron Laser (FEL) research facility. The FEL has already met its performance goals in the wavelength range 1.5 nm - 0.15 nm. This facility, the Linac Coherent Light Source (LCLS), utilizes the SLAC 2-Mile Linear Accelerator (linac) and will produce sub-picosecond pulses of short wavelength X-rays with very high peak brightness and almost complete transverse coherence. The final one-third of the SLAC linac is used as the source of electrons for the LCLS. The high energy electrons are transported across the SLAC Research Yard, into a tunnel which houses a long undulator. In passing through the undulator, the electrons are bunched by the force of their own synchrotron radiation and produce an intense, monochromatic, spatially coherent beam of X-rays. By varying the electron energy, the FEL X-ray wavelength is tunable from 1.5 nm to 0.15 nm. The LCLS includes two experimental halls as well as X-ray optics and infrastructure necessary to create a facility that can be developed for research in a variety of disciplines such as atomic physics, materials science, plasma physics and biosciences. This Conceptual Design Report, the authors believe, confirms the feasibility of designing and constructing an X-ray instrument in order to exploit the unique scientific capability of LCLS by creating extreme conditions and study the behavior of plasma under those controlled conditions. This instrument will address the Office of Science, Fusion Energy Sciences, mission objective related to study of Plasma and Warm Dense Matter as described in the report titled LCLS, the First Experiments, prepared by the LCLS Scientific Advisory Committee (SAC) in September 2000. The technical objective of the LCLS Matter in Extreme Conditions (MEC) Instrument project is

  16. Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Warren, B.

    2012-12-01

    We present results from the grant entitled, Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions. The research significantly advanced the understanding of basic high-energy density science (HEDS) on ultra intense laser and particle beam plasma interactions. This advancement in understanding was then used to to aid in the quest to make 1 GeV to 500 GeV plasma based accelerator stages. The work blended basic research with three-dimensions fully nonlinear and fully kinetic simulations including full-scale modeling of ongoing or planned experiments. The primary tool was three-dimensional particle-in-cell simulations. The simulations provided a test bed for theoretical ideas and models as well as a method to guide experiments. The research also included careful benchmarking of codes against experiment. High-fidelity full-scale modeling provided a means to extrapolate parameters into regimes that were not accessible to current or near term experiments, thereby allowing concepts to be tested with confidence before tens to hundreds of millions of dollars were spent building facilities. The research allowed the development of a hierarchy of PIC codes and diagnostics that is one of the most advanced in the world.

  17. X-ray diagnostics for laser matter interaction experiments; Diagnostics X pour les experiences d'interaction laser-matiere

    Energy Technology Data Exchange (ETDEWEB)

    Troussel, Ph

    2000-07-01

    Advances in the field of laser-driven inertially confined thermonuclear fusion research since the early 1990's are reviewed. It covers the experimental techniques used to study the interaction of laser radiation with matter and high density plasma. A high performance instrumentation (diagnostics) for observation of X radiation (from a few eV to a few keV) will be required to understand the physical processes involved in the interaction. This paper is a three-part: first part, describes diagnostics metrology realized around different X-ray sources (synchrotron, laser plasma...); a second part, synthesizes theoretical and experimental X-ray optics studies and show the interest for direct applications as X-ray spectroscopy and X-ray imaging around laser-produced plasma; a third part, is a review of high resolution X-ray imaging, performances of these optical system were summarized. (author)

  18. MSW student perceptions of sexual health as relevant to the profession: Do social work educational experiences matter?

    Science.gov (United States)

    Winter, Virginia Ramseyer; O'Neill, Elizabeth; Begun, Stephanie; Kattari, Shanna K; McKay, Kimberly

    2016-09-01

    Many social work clients are at an increased risk for negative outcomes related to sexual behavior, including unwanted pregnancies and sexually transmitted infections (STIs). However, there is a dearth of literature on social work student experiences with these topics in social work classrooms and their perceptions about the topic's relevance to their practice. The purpose of this study is to explore relationships between experiences with STIs and contraception as topics in social work education and practica experiences on student perceptions toward sexual health as a relevant topic for social work. Among a national sample of MSW students (N = 443), experiences with STIs and contraception as topics in practica was significantly related to perceptions toward sexual health's relevance to social work. Findings and implications are discussed.

  19. Travel in the heart of matter: the Atlas experiment at CERN, pop-up book; Voyage au coeur de la matiere: l'experience Atlas au CERN, Livre anime

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Emma; Radevsky, Anton; Blanche, Eugenie

    2011-12-01

    This 'pop-up' book, fully illustrated, proposes a travel towards the birth of the universe through Atlas, one of the four particle physics experiments at the Large Hadron Collider at CERN (LHC). The ATLAS detector is searching for new discoveries in the head-on collisions of protons of extraordinarily high energy. ATLAS will learn about the basic forces that have shaped our Universe since the beginning of time and that will determine its fate. Among the possible unknowns are the search for the Higgs boson, the origin of mass, the extra dimensions of space, the unification of fundamental forces, and evidence for dark matter candidates in the Universe

  20. Dark Matter Constituents

    CERN Document Server

    Bergström, L

    2005-01-01

    As cosmology has entered a phase of precision experiments, the content of the universe has been established to contain interesting and not yet fully understood components, namely dark energy and dark matter. While the cause and exact nature of the dark energy remains mysterious, there is greater hope to connect the dark matter to current models of particle physics. Supersymmetric models provide several excellent candidates for dark matter, with the lightest neutralino the prime example. This and other dark matter candidates are discussed, and prospects for their detection summarized. Some methods of detection are explained, and indications of signals in present data are critically examined.

  1. Designing Recreational Virtual Environments for Older Adult Nursing Home Residents - How Nature And Content Matter For Improving Augmented Exercise Experiences

    DEFF Research Database (Denmark)

    Bruun-Pedersen, Jon Ram; Serafin, Stefania; Maculewicz, Justyna

    2016-01-01

    In this paper, we discuss the design for restorative virtual environments (RVEs), specifically developed to augment rehabilitation exercise for older adult users living at nursing homes, in order to increase exercise motivation. User evaluations on these RVE designs suggest that the soundscapes did...... not have a noticeable role for user experience. Moreover, soundscapes might simply be perceived congruent with the visuals, and thus seamlessly accepted by users as an inherent part of the augmented exercise experience....

  2. Cleaning up dark matter

    CERN Multimedia

    Bignami, Giovanni Fabrizio

    2006-01-01

    "An experiment in Italy has found tantalizing but puzzling evidence for axions, one if the leading candidates for dark matter. The authors explain how a pair of spinning neutron stars should settle the issue once and for all." (3 pages)

  3. Analysing soft matter

    Directory of Open Access Journals (Sweden)

    Tom McLeish

    2005-09-01

    Full Text Available A new volume on soft materials ranges broadly across systems and techniques, experiment, and theory. Despite a lack of coherence, there is much of interest, which conveys the energy within soft-matter science, says

  4. Does Scale Matter? The Role of Vegetation in Controlling Morphodynamics in Large- and Small-Scale Delta Experiments

    Science.gov (United States)

    Piliouras, A.; Kim, W.

    2015-12-01

    Experimental deltas are often braided systems with highly mobile channels that rapidly rework the topset surface. Plants can aid in decreasing channel mobility and creating more stable distributary networks. Here we compare two sets of experiments that used alfalfa as a proxy for delta vegetation to determine the effects of plants on delta and channel dynamics. One set of experiments was conducted with relatively low water and sediment discharge, and the second had an order of magnitude higher water discharge than the first. We found that the low discharge experiments had multiple small bifurcating channels that could easily be annealed by floods and were not capable of removing vegetation. This resulted in relatively uniform sediment delivery to the shoreline, thus forming a smooth shoreline planform pattern. The high discharge experiments had a more two-way feedback between the channels and plants, in which the plants constricted the flow into channels and the resulting strong channels were able to erode vegetated banks. The flow constriction created two dominant channels that were more persistent than in the low discharge experiments. This resulted in a highly irregular shoreline punctuated by a few active lobes of deposition. Much of this variability was a function of channel depth, since channels must be deeper than plant roots in order to effectively erode vegetated banks. Thus, the scale at which we choose to model deltas may give drastically different results, as our two sets of experiments showed a range of delta geometries, shoreline rugosity, and channel networks. For deltas in particular, it is important to understand this variability as we plan coastal restoration efforts and try to predict the optimal discharge conditions to build new deltas on the coast.

  5. Probing the Supersymmetric Inflaton and Dark Matter link via the CMB, LHC and XENON1T experiments

    CERN Document Server

    hm, Céline Bœ; Mazumdar, Anupam; Pukartas, Ernestas

    2012-01-01

    The primordial inflation dilutes all matter except the quantum fluctuations which we see in the cosmic microwave background (CMB) radiation. Therefore the last phases of inflation must be embedded within a beyond the Standard Model (SM) sector where the inflaton can directly excite the SM quarks and leptons. In this paper we consider two inflaton candidates LLe and udd whose decay can naturally excite all the relevant degrees of freedom besides thermalizing the lightest supersymmetric particle (LSP) during and after reheating. In particular, we present the regions of the parameter space which can yield successful inflation with the right temperature anisotropy in the CMB, the observed relic density for the neutralino LSP, and the recent Higgs mass constraints from LHC within the MSSM with non-universal Higgs masses -- referred to as the NUHM2 model. We found that in most scenarios, the LSP seems strongly mass degenerated with the next to lightest LSP (NLSP) and the branching ratio B_s -> mu^+ mu^- very close ...

  6. First background-free limit from a directional dark matter experiment: results from a fully fiducialised DRIFT detector

    CERN Document Server

    Battat, J B R; Daw, E; Dorofeev, A; Ezeribe, A C; Gauvreau, J -L; Gold, M; Harton, J L; Landers, J M; Law, E; Lee, E R; Loomba, D; Lumnah, A; Matthews, J A J; Miller, E H; Monte, A; Mouton, F; Murphy, A StJ; Paling, S M; Phan, N; Robinson, M; Sadler, S W; Scarff, A; Schuckman, F; Snowden-Ifft, D P; Spooner, N J C; Telfer, S; Vahsen, S E; Walker, D; Warner, D; Yuriev, L

    2014-01-01

    The addition of O2 to gas mixtures in time projection chambers containing CS2 has recently been shown to produce multiple negative ions that travel at slightly different velocities. This allows a measurement of the absolute position of ionising events in the z (drift) direction. In this work, we apply the z-fiducialisation technique to a directional dark matter search. In particular, we present results from a 46.3 live-day source-free exposure of the DRIFT-IId detector run in this completely new mode. With full-volume fiducialisation, we have achieved the first background-free operation of a directional detector. The resulting exclusion curve for spin-dependent WIMP-proton interactions reaches 0.9 pb at 100 GeV/c2, a factor of 2 better than our previous work. We describe the automated analysis used here, and argue that detector upgrades, implemented after the acquisition of these data, will bring an additional factor of >3 improvement in the near future.

  7. Does the number of choice sets matter? Results from a web survey applying a discrete choice experiment

    DEFF Research Database (Denmark)

    Bech, Mickael; Kjær, Trine; Lauridsen, Jørgen Trankjær

    2011-01-01

    Optimising the design of discrete choice experiments (DCE) involves maximising not only the statistical efficiency, but also how the nature and complexity of the experiment itself affects model parameters and variance. The present paper contributes by investigating the impact of the number of DCE...... in standard deviations for WTP estimates or goodness-of-fit statistics. Respondents exposed to 17 choice sets had somewhat higher response variance compared to those exposed to 5 choice sets, indicating that cognitive burden may increase with the number of choice sets beyond a certain threshold. Overall, our...

  8. Dark matter

    OpenAIRE

    Einasto, J.

    2011-01-01

    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. Properties of dark matter particles determine the structure of the cosmic web.

  9. Accurate Exchange-Correlation Energies for the Warm Dense Electron Gas.

    Science.gov (United States)

    Malone, Fionn D; Blunt, N S; Brown, Ethan W; Lee, D K K; Spencer, J S; Foulkes, W M C; Shepherd, James J

    2016-09-09

    The density matrix quantum Monte Carlo (DMQMC) method is used to sample exact-on-average N-body density matrices for uniform electron gas systems of up to 10^{124} matrix elements via a stochastic solution of the Bloch equation. The results of these calculations resolve a current debate over the accuracy of the data used to parametrize finite-temperature density functionals. Exchange-correlation energies calculated using the real-space restricted path-integral formalism and the k-space configuration path-integral formalism disagree by up to ∼10% at certain reduced temperatures T/T_{F}≤0.5 and densities r_{s}≤1. Our calculations confirm the accuracy of the configuration path-integral Monte Carlo results available at high density and bridge the gap to lower densities, providing trustworthy data in the regime typical of planetary interiors and solids subject to laser irradiation. We demonstrate that the DMQMC method can calculate free energies directly and present exact free energies for T/T_{F}≥1 and r_{s}≤2.

  10. Accurate exchange-correlation energies for the warm dense electron gas

    OpenAIRE

    Malone, FD; Blunt, NS; Brown, EW; Lee, DKK; Spencer, JS; Foulkes, WMC; Shepherd, JJ

    2016-01-01

    Density matrix quantum Monte Carlo (DMQMC) is used to sample exact-on-average $N$-body density matrices for uniform electron gas systems of up to 10$^{124}$ matrix elements via a stochastic solution of the Bloch equation. The results of these calculations resolve a current debate over the accuracy of the data used to parametrize finite-temperature density functionals. Exchange-correlation energies calculated using the real-space restricted path-integral formalism and the $k$-space configurati...

  11. Ab initio study of thermodynamically consistent equation of state of warm dense aluminum plasma

    Science.gov (United States)

    Gao, Xiang; Chen, Liang; Valencia, Ramón; Xia, Weiyi; Gao, Weiwei; Han, Xiao-Ying; Li, Jia-Ming; Zhang, Peihong

    2016-09-01

    Thermodynamically consistent equation of state (EOS) of two-temperature aluminum across a wide range of parameter space (compression ratio ratios V0/V up to 4, electronic temperatures Te up to 1 500 000 K, and ionic temperature Tion up to 10 000 000 K for Te up to 40 000 K) is investigated from the free energy calculations using density functional theory (DFT) based first-principles electronic structure methods. Our results can serve as a stringent benchmark for the present EOS model and database, where various approximations are adopted, used in hydrodynamic simulations as well as developing new EOS models. We find that the Thomas-Fermi model for the electronic pressure overestimates the EOS within the present parameter space, whereas the Thomas-Fermi model with exchange corrections are in good agreement with our results for Te greater than 600 000 K. The ionic pressure for a given ionic temperature Tion is found to be nearly independent of the electronic temperature at high temperatures, which can be modeled with kinetic theory for Tion larger than 1 000 000 K for various Te. The asymptotic behavior of the electronic contributions to the plasma pressure is further analyzed and casted into a compact analytical form with a few fitting parameters. This analytical form is physically well motivated and reproduces the desired asymptotic behaviors of the EOS within the interested parameter space. Therefore, our results can be conveniently used for modeling important properties and processes of high energy density systems.

  12. Family matters : The experiences and opinions of family members of persons with (severe) or profound intellectual disabilities

    NARCIS (Netherlands)

    Luijkx, Jorien

    2016-01-01

    “I love my sister, but sometimes I don’t”. This is one of the statements made in the study focused on the experiences of family members of people with (profound) intellectual (and multiple) disabilities (both of individuals living in a residential facility as persons living at home). In recent years

  13. Experiments on the photophoretic motion of chondrules and dust aggregates -Indications for the transport of matter in protoplanetary disks

    DEFF Research Database (Denmark)

    Wurm, Gerhard; Teiser, Jens; Bischoff, Addi;

    2010-01-01

    In a set of 16 drop tower experiments the motion of sub-millimeter to millimeter-sized particles under microgravity was observed. Illumination by a halogen lamp induced acceleration of the particles due to photophoresis. Photophoresis on dust-free chondrules, on chondrules, glass spheres and meta...

  14. Associations between Child Sexual Abuse and Negative Sexual Experiences and Revictimization among Women: Does Measuring Severity Matter?

    Science.gov (United States)

    Loeb, Tamra B.; Gaines, Tommi; Wyatt, Gail E.; Zhang, Muyu; Liu, Honghu

    2011-01-01

    Women with histories of child sexual abuse (CSA) are more likely than those without such experiences to report a variety of negative sexual outcomes. This study examines the explanatory power of a CSA summed composite versus dichotomous (presence/absence) measurement in predicting a comprehensive negative sexual behavior outcome. Study…

  15. 'My culture haunts me no matter where I go': Iranian-American women discussing sexual and acculturation experiences.

    Science.gov (United States)

    Rashidian, Mitra; Hussain, Rafat; Minichiello, Victor

    2013-01-01

    Iranian-American womens' perceptions of their sexual-selves and gender roles are influenced both by the cultural context of their life experience in Iran and their acculturation in the USA. In a qualitative study, using narrative as methodology and a feminist theoretical framework, individual interviews were conducted with 24 first-generation Iranian-American women in southern California. The narratives revealed that these Iranian-American women felt attached to their home culture while also having a desire to distinguish themselves from it. In so doing, they realised that their individual sexual-selves and gender roles stemmed from their life experiences, such as home culture memories and new cultural exposures. The degrees of adjustment during the acculturation process provided women with challenges in dealing with the consequences of new experiences and the shame and guilt of shedding old cultural norms. Acculturation offered these Iranian-American women a fuller understanding of their gender role and sexual-self perceptions. An understanding of cultural impact on women's life experiences may assist healthcare professionals in their efforts to assist women in determining innovative intervention where the needs of gender role and sexual-self-concept are concerned.

  16. When Gray Matters More than Black or White: The Schooling Experiences of Black-White Biracial Students

    Science.gov (United States)

    Williams, Rhina Maria Fernandes

    2013-01-01

    Although research is scant, there is a growing interest in the manifestation of the racial and cultural context on the schooling of biracial students. The purpose of this qualitative research study was to explore the schooling experiences of 10 Black-White biracial students. Specifically, the goals of the study were to (a) identify the factors…

  17. Giving voice to quality and safety matters at board level: A qualitative study of the experiences of executive nurses working in England and Wales.

    Science.gov (United States)

    Jones, Aled; Lankshear, Annette; Kelly, Daniel

    2016-07-01

    Recent reports into egregious failing in the quality and safety of healthcare in the UK have focussed on the ability of executive boards to discharge their duties effectively. Inevitably the role of executive nurses, whose remit frequently includes responsibility for quality and safety, has become the object of increased scrutiny. However, limited evidence exists about the experiences of the UK's most senior nurses of working at board level. We aimed to generate empirical evidence on the experiences of executive nurses working at board level in England and Wales. We posed two research questions: What are the experiences of nurse executives working at board level? What strategies and/or processes do nurse executives deploy to ensure their views and concerns about quality and safety are taken into account at board level? Qualitative interviews using semi-structured interviews. NHS England and Wales. Purposive sample of 40 executive board nurses. Semi-structured interviews followed by a process of thematic data analysis using NVivo10 and feedback on early findings from participants. Our findings are presented under three headings: the experiences of executive nurses working with supportive, engaged boards; their experiences of being involved with unsupportive, avoidant boards with a poor understanding of safety, quality and the executive nursing role and the strategies deployed by executive nurses to ensure that the nursing voice was heard at board. Two prominent and interrelated discursive strategies were used by executive nurses - briefing and building relationships and preparing and delivering a credible case. Considerable time and effort were invested in these strategies which were described as having significant impact on individual board members and collective board decision making. These strategies, when viewed through the lens of the concept of "groupthink", can be seen to protect executive nurses from accusations by board colleagues of disloyalty whislt also

  18. Development of optical quality assurance procedures for the sensors of silicon tracking system (STS) detector of the compressed baryonic matter experiment (CBM) at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Lavrik, Evgeny [Eberhard-Karls Universitaet Tuebingen, Tuebingen (Germany); Collaboration: CBM-Collaboration

    2015-07-01

    The CBM experiment aims to study the properties of nuclear matter at high net-baryon densities. The STS is the key detector to reconstruct charged particle tracks created in heavy-ion interactions. In order to assure the quality of about 1300 silicon sensors, highly efficient and highly automated procedures need to be developed. In this contribution we report on a microscope camera based optical inspection system, used to scan along the individual sensors to recognize and classify sensor defects. Examples of these defects are: photo-resist residues, top metallization layer lithography defects, surface scratches. In order to separate and classify these defects various image-processing algorithms are used, including: pattern recognition, object classification, etc.

  19. What Matters Most to Whom: Racial, Ethnic, and Language Differences in the Health Care Experiences Most Important to Patients.

    Science.gov (United States)

    Collins, Rebecca L; Haas, Ann; Haviland, Amelia M; Elliott, Marc N

    2017-09-19

    Some aspects of patient experience are more strongly related to overall ratings of care than others, reflecting their importance to patients. However, little is known about whether the importance of different aspects of this experience differs across subgroups. To determine whether the aspects of health care most important to patients differ according to patient race, ethnicity, and language preference. In response to the 2013 Medicare Consumer Assessment of Health Plans Study (CAHPS) survey, patients rated their overall health care and completed items measuring five patient experience domains. We estimated a linear regression model to assess associations between overall rating of care and the 5 domains, testing for differences in these relationships for race/ethnicity/language groups, controlling for covariates. In total 242,782 Medicare beneficiaries, age 65 years or older. Overall rating of health care, composite patient experience scores for: doctor communication, getting needed care, getting care quickly, customer service, and care coordination. A joint test of the interactions between the composite scores and the 5 largest racial/ethnic/language subgroups was statistically significant (P <0.0001), suggesting the importance of domains varied across subgroups. Doctor communication had the strongest relationship with care ratings for non-Hispanic whites and English-preferring Hispanics. Getting needed care had the strongest relationship for Spanish-preferring Hispanics and Asian/Pacific Islanders. Doctor communication and getting care quickly were strongest for African Americans. Tailoring quality improvement programs to the factors most important to the racial, ethnic, and language mix of the patient population of the practice, hospital, or plan may more efficiently reduce disparities and improve quality.

  20. Does palliative care education matter to medical students? The experience of attending an undergraduate course in palliative care.

    Science.gov (United States)

    Centeno, Carlos; Ballesteros, Montse; Carrasco, José Miguel; Arantzamendi, María

    2016-03-01

    Palliative care (PC) education has become a priority in many European countries where PC is quickly developing. There remains, however, a lack of information on acceptability and medical students' experiences in PC education. This kind of information is important because it could encourage universities to adapt their curricula appropriately to the demographic and societal necessity. To explore medical students' reactions to an optional PC course using their reflective written comments. 316 medical students at the University of Navarra, over a period of 4 years, wrote evaluative comments regarding their experience and what they perceived as the course's contribution to their education. With these comments, a qualitative thematic analysis was carried out. With a response ratio of 90%, five main themes were identified: (1) The course helped medical students to become and act as doctors, (2) The benefits of having a holistic view of the patient and taking the family into account, (3) PC opens up a new a field of knowledge, (4) The course makes students think and reflect on their personal development and encourages them to deepen humanistic aspects of their practice, (5) The practical aspect is essential in PC learning. In addition, significantly, students used vigorous and positive expressions when writing about their experiences. The subject of PC turns out to be very important to students, who almost unanimously evaluated their experience positively and highlighted the benefits of attending a PC course. Students especially reported being surprised by the humane and holistic features of the course, and they found that what they learned in the course is applicable to all patients and prepares them to work better as doctors. Participants recommend the course for all undergraduate students as a core component of the curricula. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. 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

  2. Maintaining physical exercise as a matter of synchronising practices: Experiences and observations from training in Mixed Martial Arts.

    Science.gov (United States)

    Blue, Stanley

    2016-11-25

    This paper is concerned with the establishment, maintenance, and decline of physical exercise practices. Drawing on experiences and observations taken from a carnal ethnography and rhythmanalysis of the practices involved in training in Mixed Martial Arts (MMA), I argue that maintaining this physical exercise practice is not straightforwardly an outcome of individual commitment, access to facilities, or the availability of free time. It rather depends on the synchronisation of practices: those of MMA, those that support MMA, and those that more broadly make up everyday life. This research suggests that increasing rates of physical activity might be better fostered through facilitating the integration of combinations of healthy activities into everyday life.

  3. The LVD Core Facility: a study of LVD as muon veto and active shielding for dark matter experiments

    CERN Document Server

    Selvi, Marco

    2008-01-01

    In this study we explore the possibility of using the existing structure of a running experiment, the LVD supernova observatory at the INFN Gran Sasso National Laboratory, as an active shield and veto for the muon-induced background. In our vision LVD could become (without affecting in any way its main purpose of SN neutrino telescope) a host for a relatively compact but massive experiment looking for rare events. The empty volume that can be obtained removing 2 modules from the most internal part of the detector is 2.1m x 6.2m x 2.8m; we will call it LVD Core Facility (LVD-CF). We have evaluated the active vetoing and shielding power of LVD, with a detailed MC simulation (based on Geant4) of the detector and the rock that surrounds it. The results show that the flux of neutrons that are not associated with a visible muon in LVD is very low; it results reduced by a factor 50, equivalent to the one present in a much deeper underground laboratory, i.e. Sudbury. Moreover we present the results of on-going measur...

  4. 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....

  5. Memory Matters

    Science.gov (United States)

    ... Emergency Room? What Happens in the Operating Room? Memory Matters KidsHealth > For Kids > Memory Matters A A ... of your complex and multitalented brain. What Is Memory? When an event happens, when you learn something, ...

  6. Simulations of beam-matter interaction experiments at the CERN HiRadMat facility and prospects of high-energy-density physics research.

    Science.gov (United States)

    Tahir, N A; Burkart, F; Shutov, A; Schmidt, R; Wollmann, D; Piriz, A R

    2014-12-01

    In a recent publication [Schmidt et al., Phys. Plasmas 21, 080701 (2014)], we reported results on beam-target interaction experiments that have been carried out at the CERN HiRadMat (High Radiation to Materials) facility using extended solid copper cylindrical targets that were irradiated with a 440-GeV proton beam delivered by the Super Proton Synchrotron (SPS). On the one hand, these experiments confirmed the existence of hydrodynamic tunneling of the protons that leads to substantial increase in the range of the protons and the corresponding hadron shower in the target, a phenomenon predicted by our previous theoretical investigations [Tahir et al., Phys. Rev. ST Accel. Beams 25, 051003 (2012)]. On the other hand, these experiments demonstrated that the beam heated part of the target is severely damaged and is converted into different phases of high energy density (HED) matter, as suggested by our previous theoretical studies [Tahir et al., Phys. Rev. E 79, 046410 (2009)]. The latter confirms that the HiRadMat facility can be used to study HED physics. In the present paper, we give details of the numerical simulations carried out to understand the experimental measurements. These include the evolution of the physical parameters, for example, density, temperature, pressure, and the internal energy in the target, during and after the irradiation. This information is important in order to determine the region of the HED phase diagram that can be accessed in such experiments. These simulations have been done using the energy deposition code fluka and a two-dimensional hydrodynamic code, big2, iteratively.

  7. Release of Reactive Halogen Species from Sea-Salt Aerosols under Tropospheric Conditions with/without the Influence of Organic Matter in Smog-Chamber Experiments

    Science.gov (United States)

    Balzer, N.; Behnke, W.; Bleicher, S.; Krueger, H.; Ofner, J.; Siekmann, F.; Zetzsch, C.

    2008-12-01

    Experiments to investigate the release of reactive halogen species from sea-salt aerosol and the influence of organic matter were performed in an aerosol smog-chamber (3500 l), made of Teflon film (FEP 200A, Dupont). Smog chamber facilities at lowered temperature (coolable down to -25°C) enable us to simulate these reactions under polar, tropospheric conditions. First experiments were performed to investigate the production of atomic Br and Cl without the impact of organic aerosol. Br and Cl play an important role in atmospheric ozone depletion, particularly regarding ozone depletion events (bromine explosion) during polar spring. In these studies, the aerosol was generated by atomizing salt solutions containing the typical Br/Cl ratio of 1/660 in seawater by an ultrasonic nebulizer and increasing the Br content up to sixfold. To ensure the aqueous surface of the aerosol, the experiments were performed at relative humidities above 76%. We determined the atomic Cl and OH-radical concentrations from the simultaneous consumption of four reference hydrocarbons. The Br-radical concentration was calculated on the basis of ozone depletion. Organic aerosol may take part in these reaction cycles by halogenation and production of volatile organic halogens. Further experiments are planned to add organic aerosol for mechanistic and kinetic studies on the influence of secondary organic aerosols (SOA) and humic-like substances (HULIS) on bromine explosion. The formation of the secondary organic aerosol and the determination of possible halogenated gaseous and solid organic products will be studied using longpath-FTIR, DRIFTS, ATR-FTIR, GC-FID, GC-ECD, GC-MS, TPD-MS and DMA-CNC.

  8. Does Money Really Matter? Estimating Impacts of Family Income on Young Children's Achievement With Data From Random-Assignment Experiments

    Science.gov (United States)

    Duncan, Greg J.; Morris, Pamela A.; Rodrigues, Chris

    2011-01-01

    Social scientists do not agree on the size and nature of the causal impacts of parental income on children's achievement. We revisit this issue using a set of welfare and antipoverty experiments conducted in the 1990s. We utilize an instrumental variables strategy to leverage the variation in income and achievement that arises from random assignment to the treatment group to estimate the causal effect of income on child achievement. Our estimates suggest that a $1,000 increase in annual income increases young children's achievement by 5%–6% of a standard deviation. As such, our results suggest that family income has a policy-relevant, positive impact on the eventual school achievement of preschool children. PMID:21688900

  9. Interaction of Polar and Nonpolar Organic Pollutants with Soil Organic Matter: Sorption Experiments and Molecular Dynamics Simulation

    CERN Document Server

    Ahmed, Ashour A; Aziz, Saadullah G; Hilal, Rifaat H; Elroby, Shaaban A; Al-Youbi, Abdulrahman O; Leinweber, Peter; Kühn, Oliver

    2014-01-01

    The fate of organic pollutants in the environment is influenced by several factors including the type and strength of their interactions with soil components especially SOM. However, a molecular level answer to the question How organic pollutants interact with SOM? is lacking. In order to explore mechanisms of this interaction, we have developed a new SOM model followed by carrying out molecular dynamics (MD) simulations in parallel with sorption experiments. The new SOM model comprises free SOM functional groups (carboxylic acid and naphthalene) as well as SOM cavities (with two different sizes), representing the soil voids, containing the same SOM functional groups. To examine the effect of the hydrophobicity on the interaction, the organic pollutants hexachlorobenzene (HCB, non-polar) and sulfanilamide (SAA, polar) were considered. The experimental and the theoretical outcomes explored four major points regarding sorption of SAA and HCB on soil. 1. The interaction depends on the SOM chemical composition mo...

  10. Choice of experimental venue matters in ecotoxicology studies: Comparison of a laboratory-based and an outdoor mesocosm experiment.

    Science.gov (United States)

    Mikó, Zsanett; Ujszegi, János; Gál, Zoltán; Imrei, Zoltán; Hettyey, Attila

    2015-10-01

    The heavy application of pesticides and its potential effects on natural communities has attracted increasing attention to inadvertent impacts of these chemicals. Toxicologists conventionally use laboratory-based tests to assess lethal concentrations of pesticides. However, these tests often do not take into account indirect, interactive and long-term effects, and tend to ignore different rates of disintegration in the laboratory and under natural conditions. Our aim was to investigate the importance of the experimental venue for ecotoxicology tests. We reared tadpoles of the agile frog (Rana dalmatina) in the laboratory and in outdoor mesocosms and exposed them to three initial concentrations of a glyphosate-based herbicide (0, 2 and 6.5 mg a.e./L glyphosate), and to the presence or absence of caged predators (dragonfly larvae). The type of experimental venue had a large effect on the outcome: The herbicide was less lethal to tadpoles reared in outdoor mesocosms than in the laboratory. Further, while the herbicide had a negative effect on development time and on body mass in the laboratory, tadpoles exposed to the herbicide in mesocosms were larger at metamorphosis and developed faster in comparison to those reared in the absence of the herbicide. The effect of the herbicide on morphological traits of tadpoles also differed between the two venues. Finally, in the presence of the herbicide, tadpoles tended to be more active and to stay closer to the bottom of laboratory containers, while tadpole behaviour shifted in the opposite direction in outdoor mesocosms. Our results demonstrate major discrepancies between results of a classic laboratory-based ecotoxicity test and outcomes of an experiment performed in outdoor mesocosms. Consequently, the use of standard laboratory tests may have to be reconsidered and their benefits carefully weighed against the difficulties of performing experiments under more natural conditions. Tests validating experimentally estimated

  11. Estimating the Distribution of Colored Dissolved Organic Matter During the Southern Ocean Gas Exchange Experiment Using Four-Dimensional Variational Data Assimilation

    Science.gov (United States)

    Del Castillo, C. E.; Dwivedi, S.; Haine, T. W. N.; Ho, D. T.

    2017-01-01

    We diagnosed the effect of various physical processes on the distribution of mixed-layer colored dissolved organic matter (CDOM) and a sulfur hexauoride (SF6) tracer during the Southern Ocean Gas Exchange Experiment (SO GasEx). The biochemical upper ocean state estimate uses in situ and satellite biochemical and physical data in the study region, including CDOM (absorption coefcient and spectral slope), SF6, hydrography, and sea level anomaly. Modules for photobleaching of CDOM and surface transport of SF6 were coupled with an ocean circulation model for this purpose. The observed spatial and temporal variations in CDOM were captured by the state estimate without including any new biological source term for CDOM, assuming it to be negligible over the 26 days of the state estimate. Thermocline entrainment and photobleaching acted to diminish the mixed-layer CDOM with time scales of 18 and 16 days, respectively. Lateral advection of CDOM played a dominant role and increased the mixed-layer CDOM with a time scale of 12 days, whereas lateral diffusion of CDOM was negligible. A Lagrangian view on the CDOM variability was demonstrated by using the SF6 as a weighting function to integrate the CDOM elds. This and similar data assimilation methods can be used to provide reasonable estimates of optical properties, and other physical parameters over the short-term duration of a research cruise, and help in the tracking of tracer releases in large-scale oceanographic experiments, and in oceanographic process studies.

  12. Estimating the distribution of colored dissolved organic matter during the Southern Ocean Gas Exchange Experiment using four-dimensional variational data assimilation

    Science.gov (United States)

    Del Castillo, C. E.; Dwivedi, S.; Haine, T. W. N.; Ho, D. T.

    2017-03-01

    We diagnosed the effect of various physical processes on the distribution of mixed-layer colored dissolved organic matter (CDOM) and a sulfur hexafluoride (SF6) tracer during the Southern Ocean Gas Exchange Experiment (SO GasEx). The biochemical upper ocean state estimate uses in situ and satellite biochemical and physical data in the study region, including CDOM (absorption coefficient and spectral slope), SF6, hydrography, and sea level anomaly. Modules for photobleaching of CDOM and surface transport of SF6 were coupled with an ocean circulation model for this purpose. The observed spatial and temporal variations in CDOM were captured by the state estimate without including any new biological source term for CDOM, assuming it to be negligible over the 26 days of the state estimate. Thermocline entrainment and photobleaching acted to diminish the mixed-layer CDOM with time scales of 18 and 16 days, respectively. Lateral advection of CDOM played a dominant role and increased the mixed-layer CDOM with a time scale of 12 days, whereas lateral diffusion of CDOM was negligible. A Lagrangian view on the CDOM variability was demonstrated by using the SF6 as a weighting function to integrate the CDOM fields. This and similar data assimilation methods can be used to provide reasonable estimates of optical properties, and other physical parameters over the short-term duration of a research cruise, and help in the tracking of tracer releases in large-scale oceanographic experiments, and in oceanographic process studies.

  13. Dark matter searches

    CERN Document Server

    Baudis, Laura

    2015-01-01

    One of the major challenges of modern physics is to decipher the nature of dark matter. Astrophysical observations provide ample evidence for the existence of an invisible and dominant mass component in the observable universe, from the scales of galaxies up to the largest cosmological scales. The dark matter could be made of new, yet undiscovered elementary particles, with allowed masses and interaction strengths with normal matter spanning an enormous range. Axions, produced non-thermally in the early universe, and weakly interacting massive particles (WIMPs), which froze out of thermal equilibrium with a relic density matching the observations, represent two well-motivated, generic classes of dark matter candidates. Dark matter axions could be detected by exploiting their predicted coupling to two photons, where the highest sensitivity is reached by experiments using a microwave cavity permeated by a strong magnetic field. WIMPs could be directly observed via scatters off atomic nuclei in underground, ultr...

  14. Production, partitioning and stoichiometry of organic matter under variable nutrient supply during mesocosm experiments in the tropical Pacific and Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    J. M. S. Franz

    2012-11-01

    Full Text Available Oxygen-deficient waters in the ocean, generally referred to as oxygen minimum zones (OMZ, are expected to expand as a consequence of global climate change. Poor oxygenation is promoting microbial loss of inorganic nitrogen (N and increasing release of sediment-bound phosphate (P into the water column. These intermediate water masses, nutrient-loaded but with an N deficit relative to the canonical N:P Redfield ratio of 16:1, are transported via coastal upwelling into the euphotic zone. To test the impact of nutrient supply and nutrient stoichiometry on production, partitioning and elemental composition of dissolved (DOC, DON, DOP and particulate (POC, PON, POP organic matter, three nutrient enrichment experiments were conducted with natural microbial communities in shipboard mesocosms, during research cruises in the tropical waters of the southeast Pacific and the northeast Atlantic. Maximum accumulation of POC and PON was observed under high N supply conditions, indicating that primary production was controlled by N availability. The stoichiometry of microbial biomass was unaffected by nutrient N:P supply during exponential growth under nutrient saturation, while it was highly variable under conditions of nutrient limitation and closely correlated to the N:P supply ratio, although PON:POP of accumulated biomass generally exceeded the supply ratio. Microbial N:P composition was constrained by a general lower limit of 5:1. Channelling of assimilated P into DOP appears to be the mechanism responsible for the consistent offset of cellular stoichiometry relative to inorganic nutrient supply and nutrient drawdown, as DOP build-up was observed to intensify under decreasing N:P supply. Low nutrient N:P conditions in coastal upwelling areas overlying O2-deficient waters seem to represent a net source for DOP, which may stimulate growth of diazotrophic phytoplankton. These results demonstrate that microbial nutrient assimilation and

  15. Optical response of highly reflective film used in the water Cherenkov muon veto of the XENON1T dark matter experiment

    Science.gov (United States)

    Geis, Ch.; Grignon, C.; Oberlack, U.; Ramírez García, D.; Weitzel, Q.

    2017-06-01

    The XENON1T experiment is the most recent stage of the XENON Dark Matter Search, aiming for the direct detection of dark matter candidates, such as the Weakly Interacting Massive Particles (WIMPs). The projected sensitivity for the spin-independent WIMP-nucleon elastic scattering cross-section is σ ≈ 2 × 10-47 cm2 for a WIMP mass of mχ = 50 GeV/c2. To reach its projected sensitivity, the background has to be reduced by two orders of magnitude compared to its predecessor XENON100. This requires a water Cherenkov muon veto surrounding the XENON1T TPC, both to shield external backgrounds and to tag muon-induced energetic neutrons through detection of a passing muon or the secondary shower induced by a muon interacting in the surrounding rock. The muon veto is instrumented with 84 8'' PMTs with high quantum efficiency (QE) in the Cherenkov regime and the walls of the watertank are clad with the highly reflective DF2000MA foil by 3M. Here, we present a study of the reflective properties of this foil, as well as the measurement of its wavelength shifting (WLS) properties. Furthermore, we present the impact of reflectance and WLS on the detection efficiency of the muon veto, through the use of a Monte Carlo simulation carried out with the Geant4 toolkit. The measurements yield a specular reflectance of ≈100% for wavelengths larger than 400 nm, while ≈90% of the incoming light below 370 nm is absorbed by the foil. Approximately 3-7.5% of the light hitting the foil within the wavelength range 250 nm leads to an increase of the efficiency of approximately 0.5%.

  16. Collisional and collision-less surface heating in intense laser matter interaction

    Science.gov (United States)

    Kemp, Andreas; Divol, Laurent

    2015-11-01

    We explore the interaction of high-contrast intense sub-100 fs laser pulses with solid density tar- gets, using numerically converged collisional particle-in-cell simulations in one two and three dimen- sions. We observe a competition between two mechanisms that can lead to plasma heating. Inverse bremsstrahlung at solid density on one hand, and electrons scattering off plasma waves on the other, can both heat the skin layer to keV temperatures on a femtosecond time scale, facilitating a heat wave and a source of MeV electrons that penetrate and heat the bulk target. Collision-less effects heat the surface effectively starting at the relativistic intensity threshold, independent of plasma density. Our numerical results show that a high-contrast 1J/100fs laser can drive a solid target into the warm dense matter regime. This system is suitable to ab-initio modeling and experimental probing. Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  17. Analysis of Molecular Geochemistry of Soil Organic Matter from 17-year Reciprocal Transplant Experiment in Arid Ecosystem: Simulated Climate Pertubation

    Science.gov (United States)

    Hess, N. J.; Tfaily, M.; Bailey, V. L.; McCue, L. A.

    2014-12-01

    Successful development of chemical profiles that link soil carbon vulnerability and resilience to climate change would greatly facilitate assessment of soil ecosystems response to global climate change. Additionally these signatures could be used to support the design of sustainable agricultural and food/energy crop security practices. We test this possibility using soils obtained from a 17-year reciprocal soil transplant experiment between two elevations in the arid environment of eastern Washington [1]. 30-cm diameter soil cores were reciprocally transplanted between the upper and lower sites. Cores were also transplanted in place to control for disturbance. Extracted subcores were incubated in environmental chambers and measured microbial respiration revealed statically a significant decrease in respiratory response as a function of temperature in cores transferred from low elevation to high elevation. We use ultra high resolution mass spectrometry to identify thousands of organic molecules and changes in geochemistry that would indicate the vulnerability of the soil ecosystem to climate perturbation. In our experiments we used methanol extraction followed by direct injection to 12 T ESI FT-ICR MS to identify about 4000 of individual compounds in about 200 mg soils at sub ppm mass accuracy. Chemical formulae were assigned to approximately 65% of the measured peaks using a modified Kujawinski pipeline and second order Kendrick transformations [2] resulted in approximately 75% assigned peaks. Our preliminary analysis finds that while the bulk C content of soils from the cooler, wetter conditions at the upper elevation is approximately twice that of the warmer, drier conditions at lower elevation, the molecular soil geochemistry is remarkably similar. Detailed analysis reveals subtle differences in the lipid, carbohydrate, and condensed hydrocarbon compositional makeup of the soil. Additionally, of the more than 17,000 individual compounds identified approximately

  18. Role of minerals in the thermal alteration of organic matter. III. Generation of bitumen in laboratory experiments

    Energy Technology Data Exchange (ETDEWEB)

    Huizinga, B.J.; Tannenbaum, E.; Kaplan, I.R.

    1987-01-01

    A series of pyrolysis experiments, utilizing two different immature kerogens (from the Monterey and Green River Formations) mixed with common sedimentary minerals (calcite, illite, or Na-montmorillonite), was conducted to study the impact of the mineral matrix on the bitumen that was generated. Calcite has no significant influence on the thermal evolution of bitumen and also shows virtually no adsorption capacity for any of the pyrolysate. In contrast, montmorillonite and illite, to a lesser extent, alter bitumen during dry pyrolysis. Montmorillonite and illite also display strong adsorption capacities for the polar constituents of bitumen. By this process, hydrocarbons are substantially concentrated within the pyrolysate that is not strongly adsorbed on the clay matrices. The effects of the clay minerals are significantly reduced during hydrous pyrolysis. The strong adsorption capacities of montmorillonite and illite, as well as their thermocatalytic properties, may in part explain why light oils and gases are generated from certain argillaceous source-rock assemblages, whereas heavy immature oils are often derived from carbonate source rocks.

  19. The role of minerals in the thermal alteration of organic matter. III - Generation of bitumen in laboratory experiments

    Science.gov (United States)

    Huizinga, Bradley J.; Tannenbaum, Eli; Kaplan, I. R.

    A series of pyrolysis experiments, utilizing two different immature kerogens (from the Monterey and Green River Formations) mixed with common sedimentary minerals (calcite, illite, or Na-montmorillonite), was conducted to study the impact of the mineral matrix on the bitumen that was generated. Calcite has no significant influence on the thermal evolution of bitumen and also shows virtually no adsorption capacity for any of the pyrolysate. In contrast, montmorillonite (M) and illite, to a lesser extent, alter bitumen during dry pyrolysis. M and illite also display strong adsorption capacities for the polar constituents of bitumen. By this process, hydrocarbons are substantially concentrated within the pyrolysate that is not strongly adsorbed on the clay matrices. The effects of the clay minerals are significantly reduced during hydrous pyrolysis. The strong adsorption capacities of M and illite, as well as their thermocatalytic properties, may in part explain why light oils and gases are generated from certain argillaceous source-rock assemblages, whereas heavy immature oils are often derived from carbonate source rocks.

  20. People and Teams Matter in Organizational Change: Professionals’ and Managers’ Experiences of Changing Governance and Incentives in Primary Care

    Science.gov (United States)

    Allan, Helen T; Brearley, Sally; Byng, Richard; Christian, Sara; Clayton, Julie; Mackintosh, Maureen; Price, Linnie; Smith, Pam; Ross, Fiona

    2014-01-01

    ObjectivesTo explore the experiences of governance and incentives during organizational change for managers and clinical staff. Study SettingThree primary care settings in England in 2006–2008. Study DesignData collection involved three group interviews with 32 service users, individual interviews with 32 managers, and 56 frontline professionals in three sites. The Realistic Evaluation framework was used in analysis to examine the effects of new policies and their implementation. Principal FindingsIntegrating new interprofessional teams to work effectively is a slow process, especially if structures in place do not acknowledge the painful feelings involved in change and do not support staff during periods of uncertainty. ConclusionsEliciting multiple perspectives, often dependent on individual occupational positioning or place in new team configurations, illuminates the need to incorporate the emotional as well as technocratic and system factors when implementing change. Some suggestions are made for facilitating change in health care systems. These are discussed in the context of similar health care reform initiatives in the United States. PMID:23829292