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Sample records for central diffractive heavy

  1. Central diffraction at ALICE

    NASA Astrophysics Data System (ADS)

    Lämsä, J. W.; Orava, R.

    2011-02-01

    The ALICE experiment is shown to be well suited for studies of exclusive final states from central diffractive reactions. The gluon-rich environment of the central system allows detailed QCD studies and searches for exotic meson states, such as glueballs, hybrids and new charmonium-like states. It would also provide a good testing ground for detailed studies of heavy quarkonia. Due to its central barrel performance, ALICE can accurately measure the low-mass central systems with good purity. The efficiency of the Forward Multiplicity Detector (FMD) and the Forward Shower Counter (FSC) system for detecting rapidity gaps is shown to be adequate for the proposed studies. With this detector arrangement, valuable new data can be obtained by tagging central diffractive processes.

  2. INELASTIC DIFFRACTION AT HEAVY ION COLLIDERS.

    SciTech Connect

    WHITE, S.

    2005-01-01

    The heavy ion physics approach to global event characterization has led us to instrument the forward region in the PHENIX experiment at RHIC. In heavy ion collisions this coverage yields a measurement of the ''spectator'' energy and its distribution about the beam direction. This energy flow is the basis of event-by-event determination of the centrality and reaction plane which are key to analyzing particle production in heavy ion collisions. These same tools have also enabled a unique set of measurements on inelastic diffraction with proton, deuteron and gold ion beams in the PHENIX experiment. We present first new results on this topic and discuss briefly the opportunity for diffractive physics with Heavy Ion beams at the LHC.

  3. Central collisions of heavy ions

    SciTech Connect

    Fung, Sun-yiu.

    1992-10-01

    This report describes the activities of the Heavy Ion Physics Group at the University of California, Riverside from October 1, 1991 to September 30, 1992. During this period, the program focused on particle production at AGS energies, and correlation studies at the Bevalac in nucleus-nucleus central collisions. As part of the PHENIX collaboration, contributions were made to the Preliminary Conceptual Design Report (pCDR), and work on a RHIC silicon microstrip detector R D project was performed.

  4. Diffractive excitation of heavy flavors: Leading twist mechanisms

    SciTech Connect

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan; Tarasov, A. V.

    2007-08-01

    Diffractive production of heavy flavors is calculated within the light-cone dipole approach. Novel leading twist mechanisms are proposed, which involve both short and long transverse distances inside the incoming hadron. Nevertheless, the diffractive cross section turns out to be sensitive to the primordial transverse momenta of projectile gluons, rather than to the hadronic size. Our calculations agree with the available data for diffractive production of charm and beauty, and with the observed weak variation of the diffraction-to-inclusive cross section ratios as function of the hard scale.

  5. Communication: Heavy atom quantum diffraction by scattering from surfaces.

    PubMed

    Moix, Jeremy M; Pollak, Eli

    2011-01-01

    Typically one expects that when a heavy particle collides with a surface, the scattered angular distribution will follow classical mechanics. The heavy mass usually assures that the coherence length of the incident particle in the direction of the propagation of the particle (the parallel direction) will be much shorter than the characteristic lattice length of the surface, thus leading to a classical description. Recent work on molecular interferometry has shown that extreme collimation of the beam creates a perpendicular coherence length which is sufficiently long so as to observe interference of very heavy species passing through a grating. Here we show, using quantum mechanical simulations, that the same effect will lead to quantum diffraction of heavy particles colliding with a surface. The effect is robust with respect to the incident energy, the angle of incidence, and the mass of the particle. PMID:21218990

  6. Diffractive Higgs production from intrinsic heavy flavors in the proton

    SciTech Connect

    Brodsky, Stanley J.; Kopeliovich, Boris; Schmidt, Ivan; Soffer, Jacques

    2006-06-01

    We propose a novel mechanism for exclusive diffractive Higgs production pp{yields}pHp in which the Higgs boson carries a significant fraction of the projectile proton momentum. This mechanism will provide a clear experimental signal for Higgs production due to the small background in this kinematic region. The key assumption underlying our analysis is the presence of intrinsic heavy flavor components of the proton bound state, whose existence at the high light-cone momentum fraction x has growing experimental and theoretical support. We also discuss the implications of this picture for exclusive diffractive quarkonium and other channels.

  7. Diffractive Higgs Production from Intrinsic Heavy Flavors in the Proton

    SciTech Connect

    Brodsky, Stanley J.; Kopeliovich, Boris; Schmidt, Ivan; Soffer, Jacques

    2006-03-31

    We propose a novel mechanism for exclusive diffractive Higgs production pp {yields} pHp in which the Higgs boson carries a significant fraction of the projectile proton momentum. This mechanism will provide a clear experimental signal for Higgs production due to the small background in this kinematic region. The key assumption underlying our analysis is the presence of intrinsic heavy flavor components of the proton bound state, whose existence at high light-cone momentum fraction x has growing experimental and theoretical support. We also discuss the implications of this picture for exclusive diffractive quarkonium and other channels.

  8. Central diffractive resonance production at the LHC

    NASA Astrophysics Data System (ADS)

    Fiore, Roberto; Jenkovszky, Laszlo; Schicker, Rainer

    2016-07-01

    Central production of resonances resulting from the scattering of Pomerons in the central rapidity region of proton-proton scattering is studied. Estimates for relevant cross sections are presented. L.J. gratefully acknowledges an EMMI visiting Professorship at the University of Heidelberg for completion of this work. He is grateful to the organizers of this meeting for their hospitality and support. His work was supported also by DOMUS, Hungarian Academy of Sciences

  9. Single and Central Diffractive Higgs Production at the LHC

    SciTech Connect

    Ducati, M. B. Gay; Machado, M. M.; Silveira, G. G.

    2011-07-15

    The single and central diffractive production of the Standard Model Higgs boson is computed using the diffractive factorization formalism, taking into account a parametrization for the Pomeron structure function provided by the H1 Collaboration. We compute the cross sections at NLO accuracy for the gluon fusion process, since it is the leading mechanism for the Higgs boson production. The gap survival probability is also introduced to include the rescattering corrections due to spectator particles present in the interaction. The diffractive ratios are predicted for proton-proton collisions at the LHC, since the beam luminosity is favorable to the Higgs boson detection. These results provide updated estimations for the fraction of single and central diffractive events in the LHC kinematical regime.

  10. Estimate of the single diffractive heavy quark production in heavy ion collisions at the CERN LHC

    SciTech Connect

    Gay Ducati, M. B.; Machado, M. M.; Machado, M. V. T.

    2010-03-01

    The single diffractive cross section for heavy quarks production is calculated at next-to-leading order (for nucleus-nucleus collisions. Such processes are expected to occur at the LHC, where the nuclei involved are lead at {radical}(s)=5.5 TeV and calcium at {radical}(s)=6.3 TeV. We start using the hard diffractive factorization formalism, taking into account a recent experimental parametrization for the Pomeron structure function (DPDF). Absorptive corrections are accounted for by the multiple Pomeron contributions considering a gap survival probability, where its theoretical uncertainty for nuclear collisions is discussed. We estimate the diffractive ratios for the single diffraction process in nuclear coherent/incoherent collisions at the LHC.

  11. Microbial Diffraction Gratings as Optical Detectors for Heavy Metal Pollutants

    NASA Technical Reports Server (NTRS)

    Noever, David; Matsos, Helen; Brittain, Andrew; Obenhuber, Don; Cronise, Raymond; Armstrong, Shannon

    1996-01-01

    As a significant industrial pollutant, cadmium is implicated as the cause of itai-itai disease. For biological detection of cadmium toxicity, an assay device has been developed using the motile response of the protozoa species, Tetrahymena pyriformis. This mobile protozoa measures 50 microns in diameter, swims at 10 body lengths per second, and aggregates into macroscopically visible patterns at high organism concentrations. The assay demonstrates a Cd(+2) sensitivity better than 1 micro-M and a toxicity threshold to 5 micro-M, thus encouraging the study of these microbial cultures as viable pollution detectors. Using two-dimensional diffraction patterns within a Tetrahymena culture, the scattered light intensity varies with different organism densities (population counts). The resulting density profile correlates strongly with the toxic effects at very low dosages for cadmium (less than 5 ppm) and then for poison protection directly (with nickel and copper antagonists competing with cadmium absorption). In particular, copper dosages as low as 0.1-0.5 mM Cu have shown protective antagonism against cadmium, have enhanced density variability for cultures containing 1 mM Cd(+2) and therefore have demonstrated the sensitivity of the optical detection system. In this way, such microbial diffraction patterns give a responsive optical measure of biological culture changes and toxicity determination in aqueous samples of heavy metals and industrial pollutants.

  12. Diffractive heavy flavor production-including W/sup +-/ and Z/sup 0/

    SciTech Connect

    White, A.R.

    1986-01-01

    It is shown that when the Pomeron has the semiperturbative origin in QCD, diffractive heavy quark production is independent from, and not suppressed relative to, the perturbative gluon fusion process. It is emphasized that anomalously large diffractive heavy flavor cross-sections could anticipate correspondingly large cross-sections for the diffractive production of W/sup +-/ and Z/sup 0/-providing distinctive evidence for the dynamical nature of the electroweak Higgs sector.

  13. Central Diffractive Processes at the Tevatron, RHIC and LHC

    SciTech Connect

    Harland-Lang, L. A.; Stirling, W. J.; Khoze, V. A.; Ryskin, M. G.

    2011-07-15

    Central exclusive production (CEP) processes in high-energy hadron collisions offer a very promising framework for studying both novel aspects of QCD and new physics signals. We report on the results of a theoretical study of the CEP of heavy quarkonia ({chi} and {eta}) at the Tevatron, RHIC and LHC (see for details [1]-[3]). These processes provide important information on the physics of bound states and can probe the current ideas and methods of QCD, such as effective field theories and lattice QCD.

  14. Diffractive heavy quark production in AA collisions at the LHC at NLO

    SciTech Connect

    Machado, M. M.; Ducati, M. B. Gay; Machado, M. V. T.

    2011-07-15

    The single and double diffractive cross sections for heavy quarks production are evaluated at NLO accuracy for hadronic and heavy ion collisions at the LHC. Diffractive charm and bottom production is the main subject of this work, providing predictions for CaCa, PbPb and pPb collisions. The hard diffraction formalism is considered using the Ingelman-Schlein model where a recent parametrization for the Pomeron structure function (DPDF) is applied. Absorptive corrections are taken into account as well. The diffractive ratios are estimated and theoretical uncertainties are discussed. Comparison with competing production channels is also presented.

  15. Hadron spectroscopy in diffractive and central production processes at COMPASS

    SciTech Connect

    Jasinski, Prometeusz Kryspin

    2011-07-15

    COMPASS is a fixed-target experiment using secondary high-energetic hadron beams provided by the CERN SPS. In 2008 and 2009, a large amount of data has been collected with a 190 GeV/c pion beam for the investigation of the hadron spectrum in diffractive and central production processes. A big variety of observed final states, including {pi}{sup -}{pi}{sup +}{pi}{sup -}, {pi}{sup -}{pi}{sup 0}{pi}{sup 0}, {pi}{sup -}{eta}{eta}, {pi}{sup -}K{sub s}K{sub s}, {pi}{sup -}K{sup +}K{sup -}, K{sup -}{pi}{sup +}{pi}{sup -}, and centrally produced 4{pi}, is being analysed. The potential for systematic spectroscopic studies especially concerning the existence and nature of spin-exotic, hybrid and glueball states is discussed. In addition, we show the first results from the data set collected with a proton beam in 2008. These data indicate the chance of COMPASS to contribute to the field of baryon spectroscopy.

  16. Setup for in situ x-ray diffraction study of swift heavy ion irradiated materials

    SciTech Connect

    Kulriya, P. K.; Singh, F.; Tripathi, A.; Ahuja, R.; Kothari, A.; Dutt, R. N.; Mishra, Y. K.; Kumar, Amit; Avasthi, D. K.

    2007-11-15

    An in situ x-ray diffraction (XRD) setup is designed and installed in the materials science beam line of the Pelletron accelerator at the Inter-University Accelerator Centre for in situ studies of phase change in swift heavy ion irradiated materials. A high vacuum chamber with suitable windows for incident and diffracted X-rays is integrated with the goniometer and the beamline. Indigenously made liquid nitrogen (LN{sub 2}) temperature sample cooling unit is installed. The snapshots of growth of particles with fluence of 90 MeV Ni ions were recorded using in situ XRD experiment, illustrating the potential of this in situ facility. A thin film of C{sub 60} was used to test the sample cooling unit. It shows that the phase of the C{sub 60} film transforms from a cubic lattice (at room temperature) to a fcc lattice at around T=255 K.

  17. Seasonal impact on beach morphology and the status of heavy mineral deposition - central Tamil Nadu coast, India

    NASA Astrophysics Data System (ADS)

    Joevivek, V.; Chandrasekar, N.

    2014-02-01

    The aim of the present research was to investigate the seasonal impact on nearshore beach dynamics and the status of heavy mineral distribution along central Tamil Nadu coast, India. Beach profile measurements were made in 10 profiling sites between Thirukadaiyur and Velankanni on monthly and seasonal basis from January 2011 to July 2012. Using beach profile data, variation in beach width, slope and volumetric changes have been calculated. Beach slope and nearshore wave parameters were used to quantify the longshore sediment transport rate. Beaches between Thirukadaiyur and Karaikkal attained predominant transport rate in northern direction whereas, the rest of the beaches are in southern direction. The seasonal action of wind and wave currents create nearshore bar during northeast (NE) monsoon and frequent berms at tidal zone during southwest (SW) monsoon. Surface sediment samples were collected in each location for quantifying the heavy mineral weight percentage during the period of pre- and post-Thane cyclone. Sediments were also studied by X-ray diffraction (XRD) to evaluate the changes and occurrence of heavy minerals in beach sands. The XRD results show that sediments in the study area have enriched heavy mineral distribution even after strong cyclonic event. It confirms the redistribution of heavy mineral deposits present in the coast. The results suggested that monsoonal action has influenced the seasonal changes in beach morphology and it does not affect the heavy mineral distribution.

  18. Residual Stress Analysis of Overspeeded Disk with Central Hole by X-ray Diffraction

    NASA Technical Reports Server (NTRS)

    Good, James N

    1948-01-01

    An X-ray - diffraction analysis of residual surface stresses after plastic strain was introduced in a parallel-sided 3S-O aluminum disk with a central hole by two types of centrifugal overspeed is reported. Both tangential and radial stresses were generally tensile with large local variations near the hole where surface stresses may have been partly superficial. These stresses were both tensile and compressive dependent on the distance from the disk center when mass compression was effected near the hole.

  19. Central diffraction in proton-proton collisions at √s = 7TeV with ALICE at LHC

    NASA Astrophysics Data System (ADS)

    Reidt, Felix; Alice Collaboration

    2013-04-01

    A double-gap topology is used for filtering central-diffractive events from a protonproton minimum-bias data sample at a centre-of-mass energy Central diffraction in proton-proton collisions at √s = 7TeV. This topology is defined by particle activity in the ALICE central barrel and absence of particle activity outside. The fraction of events satisfying the double-gap requirement RDG is found to be 7.63±0.02(st at.)±0.87(syst.)×10-4. The background of this double-gap fraction is estimated by studying the contributions of non-diffractive, single-and double-diffractive dissociation processes as modelled by Monte Carlo event generators, and is found to be about 10%.

  20. Single- and central-diffractive production of open charm and bottom mesons at the LHC: Theoretical predictions and experimental capabilities

    NASA Astrophysics Data System (ADS)

    Łuszczak, Marta; Maciuła, Rafał; Szczurek, Antoni

    2015-03-01

    We discuss diffractive production of open charm and bottom mesons at the LHC. The differential cross sections for single- and central-diffractive mechanisms for c c ¯ and b b ¯ pair production are calculated in the framework of the Ingelman-Schlein model corrected for absorption effects. In this approach, one assumes that the Pomeron has a well-defined partonic structure, and that the hard process takes place in a Pomeron-proton or proton-Pomeron (single diffraction) or Pomeron-Pomeron (central diffraction) process. Here, leading-order gluon-gluon fusion and quark-antiquark annihilation partonic subprocesses are taken into consideration, which are calculated within standard collinear approximation. Both Pomeron flux factors as well as parton distributions in the Pomeron are taken from the H1 Collaboration analysis of diffractive structure function and diffractive dijets at HERA. The extra corrections from subleading Reggeon exchanges are explicitly calculated and are also taken into consideration. Several quark-level differential distributions are shown. The hadronization of charm and bottom quarks is taken into account by means of fragmentation function technique. Predictions for single- and central-diffractive production in the case of inclusive D and B mesons, as well as D D ¯ pairs, are presented, including detector acceptance of the ATLAS, CMS, and LHCb collaborations. The experimental aspects of possible standard and dedicated measurements are carefully discussed.

  1. X-ray diffraction studies of phase transformations in heavy-metal fluoride glasses

    NASA Technical Reports Server (NTRS)

    Bansal, N. P.; Doremus, R. H.

    1985-01-01

    Powder X-ray diffraction and differential scanning calorimetry studies of the crystallization properties of five ZrF4-based glass compositions have indicated that the crystalline phase in Zr-Ba-La-Pb fluoride glass is beta-BaZrF6; no such identification of crystal phases was obtainable, however, for the other glasses. Reversible polymorphic phase transformations occur in Zr-Ba-La-Li and Zr-Ba-La-Na fluoride glasses, upon heating to higher temperatures.

  2. High-resolution x-ray diffraction study of the heavy-fermion compound YbBiPt

    NASA Astrophysics Data System (ADS)

    Ueland, B. G.; Saunders, S. M.; Bud'ko, S. L.; Schmiedeshoff, G. M.; Canfield, P. C.; Kreyssig, A.; Goldman, A. I.

    2015-11-01

    YbBiPt is a heavy-fermion compound possessing significant short-range antiferromagnetic correlations below a temperature of T*=0.7 K , fragile antiferromagnetic order below TN=0.4 K , a Kondo temperature of TK≈1 K , and crystalline-electric-field splitting on the order of E /kB=1 -10 K . Whereas the compound has a face-centered-cubic lattice at ambient temperature, certain experimental data, particularly those from studies aimed at determining its crystalline-electric-field scheme, suggest that the lattice distorts at lower temperature. Here, we present results from high-resolution, high-energy x-ray diffraction experiments which show that, within our experimental resolution of ≈6 -10 ×10-5Å , no structural phase transition occurs between T =1.5 and 50 K . In combination with results from dilatometry measurements, we further show that the compound's thermal expansion has a minimum at ≈18 K and a region of negative thermal expansion for 9 ≲T ≲18 K . Despite diffraction patterns taken at 1.6 K which indicate that the lattice is face-centered cubic and that the Yb resides on a crystallographic site with cubic point symmetry, we demonstrate that the linear thermal expansion may be modeled using crystalline-electric-field level schemes appropriate for Yb3 + residing on a site with either cubic or less than cubic point symmetry.

  3. Analysis of Soil Heavy Metal Pollution and Pattern in Central Transylvania

    PubMed Central

    Suciu, Ioan; Cosma, Constantin; Todică, Mihai; Bolboacă, Sorana D.; Jäntschi, Lorentz

    2008-01-01

    The concentration of five soil heavy metals (Pb, Co, Cr, Cu, Hg) was measured in forty sampling sites in central Transylvania, Romania, regions known as centres of pollution due to the chemical and metallurgical activities. The soil samples were collected from locations where the ground is not sliding and the probability of alluvial deposits is small. The concentration of heavy metals was measured by using the Inductively Coupled Plasma Spectrometry method. Data were verified by using the Neutron Activation Analysis method. In some locations, the concentration for the investigated heavy metals exceeds the concentration admitted by the Romanian guideline. The highest concentration of lead (1521.8 ppm) and copper (1197.6 ppm) was found in Zlatna. The highest concentration of chromium was found in Târnăveni (1080 ppm). The maximum admitted concentrations in the sensitive areas revealed to be exceed from five to forty times. PMID:19325760

  4. Central Limit Theorems for Linear Statistics of Heavy Tailed Random Matrices

    NASA Astrophysics Data System (ADS)

    Benaych-Georges, Florent; Guionnet, Alice; Male, Camille

    2014-07-01

    We show central limit theorems (CLT) for the linear statistics of symmetric matrices with independent heavy tailed entries, including entries in the domain of attraction of α-stable laws and entries with moments exploding with the dimension, as in the adjacency matrices of Erdös-Rényi graphs. For the second model, we also prove a central limit theorem of the moments of its empirical eigenvalues distribution. The limit laws are Gaussian, but unlike the case of standard Wigner matrices, the normalization is the one of the classical CLT for independent random variables.

  5. Central collisions of heavy ions. Progress report, October 1, 1991--September 31, 1992

    SciTech Connect

    Fung, Sun-yiu

    1992-10-01

    This report describes the activities of the Heavy Ion Physics Group at the University of California, Riverside from October 1, 1991 to September 30, 1992. During this period, the program focused on particle production at AGS energies, and correlation studies at the Bevalac in nucleus-nucleus central collisions. As part of the PHENIX collaboration, contributions were made to the Preliminary Conceptual Design Report (pCDR), and work on a RHIC silicon microstrip detector R&D project was performed.

  6. High-resolution x-ray diffraction study of the heavy-fermion compound YbBiPt

    DOE PAGESBeta

    Ueland, B. G.; Iowa State Univ., Ames, IA; Saunders, S. M.; Iowa State Univ., Ames, IA; Bud'ko, S. L.; Iowa State Univ., Ames, IA; Schmiedeshoff, G. M.; Canfield, P. C.; Iowa State Univ., Ames, IA; Kreyssig, A.; et al

    2015-11-30

    In this study, YbBiPt is a heavy-fermion compound possessing significant short-range antiferromagnetic correlations below a temperature of T*=0.7K, fragile antiferromagnetic order below TN = 0.4K, a Kondo temperature of TK ≈ 1K, and crystalline-electric-field splitting on the order of E/kB = 1 – 10K. Whereas the compound has a face-centered-cubic lattice at ambient temperature, certain experimental data, particularly those from studies aimed at determining its crystalline-electric-field scheme, suggest that the lattice distorts at lower temperature. Here, we present results from high-resolution, high-energy x-ray diffraction experiments which show that, within our experimental resolution of ≈ 6 – 10 × 10–5 Å,more » no structural phase transition occurs between T = 1.5 and 50 K. In combination with results from dilatometry measurements, we further show that the compound's thermal expansion has a minimum at ≈ 18 K and a region of negative thermal expansion for 9 ≲ T ≲ 18 K. Despite diffraction patterns taken at 1.6 K which indicate that the lattice is face-centered cubic and that the Yb resides on a crystallographic site with cubic point symmetry, we demonstrate that the linear thermal expansion may be modeled using crystalline-electric-field level schemes appropriate for Yb3+ residing on a site with either cubic or less than cubic point symmetry.« less

  7. High-resolution x-ray diffraction study of the heavy-fermion compound YbBiPt

    SciTech Connect

    Ueland, B. G.; Saunders, S. M.; Bud'ko, S. L.; Schmiedeshoff, G. M.; Canfield, P. C.; Kreyssig, A.; Goldman, A. I.

    2015-11-30

    In this study, YbBiPt is a heavy-fermion compound possessing significant short-range antiferromagnetic correlations below a temperature of T*=0.7K, fragile antiferromagnetic order below TN = 0.4K, a Kondo temperature of TK ≈ 1K, and crystalline-electric-field splitting on the order of E/kB = 1 – 10K. Whereas the compound has a face-centered-cubic lattice at ambient temperature, certain experimental data, particularly those from studies aimed at determining its crystalline-electric-field scheme, suggest that the lattice distorts at lower temperature. Here, we present results from high-resolution, high-energy x-ray diffraction experiments which show that, within our experimental resolution of ≈ 6 – 10 × 10–5 Å, no structural phase transition occurs between T = 1.5 and 50 K. In combination with results from dilatometry measurements, we further show that the compound's thermal expansion has a minimum at ≈ 18 K and a region of negative thermal expansion for 9 ≲ T ≲ 18 K. Despite diffraction patterns taken at 1.6 K which indicate that the lattice is face-centered cubic and that the Yb resides on a crystallographic site with cubic point symmetry, we demonstrate that the linear thermal expansion may be modeled using crystalline-electric-field level schemes appropriate for Yb3+ residing on a site with either cubic or less than cubic point symmetry.

  8. High-resolution x-ray diffraction study of the heavy-fermion compound YbBiPt

    NASA Astrophysics Data System (ADS)

    Ueland, B. G.; Saunders, S. M.; Bud'Ko, S. L.; Schmiedeshoff, G. M.; Canfield, P. C.; Kreyssig, A.; Goldman, A. I.

    YbBiPt is a heavy-fermion compound possessing significant short-range antiferromagnetic correlations below T* = 0 . 7 K, fragile antiferromagnetic order below TN = 0 . 4 K, a Kondo temperature of TK ~ 1 K, and crystalline-electric-field splitting (CEF) on the order of E /kB = 1 - 10 K. Its lattice is face-centered cubic at ambient temperature, but certain data, particularly those from studies aimed at determining the CEF level scheme, suggest that the lattice distorts at lower temperature. Here, we present results from high-energy x-ray diffraction experiments which show that, within our experimental resolution of ~ 6 - 10 ×10-5 Å, no structural phase transition occurs between 1 . 5 and 50 K. Despite this result, we demonstrate that the compound's thermal expansion may be modeled using CEF level schemes appropriate for Yb3+ residing on a site with either cubic or less than cubic point symmetry. Work at the Ames Laboratory was supported by the US DOE, BES, DMSE, under Contract No. DE-AC02-07CH11358. Work at Occidental College was supported by the NSF under DMR-1408598. This research used resources at the Advanced Photon Source a US DOE, Office of Science, User Facility.

  9. Suppression of High pT Hadrons at Midrapidity in Central Heavy Ion Collisions from Phenix

    NASA Astrophysics Data System (ADS)

    Bumazhnov, V.

    2015-06-01

    Hard scattered partons lose a significant fraction of their energy traversing the medium created in high energy collisions of heavy nuclei, resulting in yields suppression of final state high pT hadrons. Results from the PHENIX experiment at RHIC on the suppression of high pT hadrons at midrapidity in central Au+Au and Cu+Cu collisions at √ {s_{NN}} = 200 ;{textrm{GeV}} are presented. In addition, results on direct photon yields, which don't suffer energy loss due to the strong nuclear force, and suppression of the high pT electrons and positrons from the decays of hadrons containing open heavy quarks are presented for Au+Au and d+Au collisions too.

  10. Electron backscattering diffraction analysis of an ancient wootz steel blade from central India

    SciTech Connect

    Barnett, M.R. Sullivan, A.; Balasubramaniam, R.

    2009-04-15

    The electron backscattering diffraction technique was used to analyse the nature of carbides present in an ancient wootz steel blade. Bulky carbides, pro-eutectoid carbide along the prior austenite grain boundaries and fine spheroidized carbides were detected. Electron backscattering diffraction was employed to understand the texture of these carbides. The orientations of the cementite frequently occur in clusters, which points to a common origin of the members of the cluster. For the bands of coarse cementite, the origin is probably large coarse particles formed during the original cooling of the wootz cake. Pearlite formed earlier in the forging process has led to groups of similarly oriented fine cementite particles. The crystallographic texture of the cementite is sharp whereas that of the ferrite is weak. The sharp cementite textures point to the longevity of the coarse cementite throughout the repeated forging steps and to the influence of existing textured cementite on the nucleation of new cementite during cooling.

  11. Temporal distribution of heavy metal concentrations in oysters Crassostrea rhizophorae from the central Venezuelan coast.

    PubMed

    Alfonso, Juan A; Handt, Helga; Mora, Abrahan; Vásquez, Yaneth; Azocar, José; Marcano, Eunice

    2013-08-15

    The oyster Crassostrea rhizophorae is a bivalve abundant in Venezuelan estuaries and consumed by local populations. No known values have been reported on trace metals in oysters from the central Venezuelan coast. We report the concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V and Zn in the soft parts of C. rhizophorae, which were collected bimonthly between March 2008 and March 2009, at two sampling areas from the Central Venezuelan Coast: Buche estuary and Mochima estuary. Our results show that for each metal there is a similar temporal variation pattern. The concentrations of the heavy metals reported in this work are useful as reliable baselines and can be used for comparison in future environment studies. Concentrations in C. rhizophorae from the Buche estuary can be interpreted to be high on a global scale for Cd, Cu, Ni and Mn, indicating atypically raised bioavailabilities. PMID:23746942

  12. Tracing isospin with the {pi}{sup -}/{pi}{sup +} ratio in central heavy ion collisions

    SciTech Connect

    Zhang Ming; Xiao Zhigang; Zhu Shengjiang

    2010-10-15

    Within an isospin- and momentum-dependent hadronic transport model, we have investigated the isospin mixing with the probe of the {pi}{sup -}/{pi}{sup +} ratio in central isospin asymmetric {sup 96}Ru+{sup 96}Zr collision at an incident energy of 400 MeV/u. The isospin equilibrium is not reached according to the asymmetrical distribution of the {pi}{sup -}/{pi}{sup +} ratio with rapidity. In comparison with the nucleon observable, it suggests that the pion ratio {pi}{sup -}/{pi}{sup +} is a promising observable to probe the relaxation of isospin degree of freedom in central heavy ion collisions without being strongly affected by the surface effect. Because of the small system size and rather strong effect of rescattering on pions, the isospin mixing shows insignificant dependence on the stiffness of the symmetry energy in the relevant colliding system.

  13. The environment quality of heavy metals in sediments from the central Bohai Sea.

    PubMed

    Liu, Ming; Zhang, Aibin; Liao, Yongjie; Chen, Bin; Fan, Dejiang

    2015-11-15

    The heavy metals (Cu, Co, Ni, Zn, Cr, Pb, Cd) in surface and core sediments from the central Bohai Sea were analyzed to evaluate the temporal/spatial distribution and pollution status. Cd exhibited gradual increase vertically, while others were stable or declined slightly in core sediments. In surface sediments, metals showed higher values in 'central mud area of the Bohai Sea' and the coastal area of the Bohai Bay. Cd and Pb also had high levels in the northeastern part of Bohai Sea. Both the contamination factors (CFs) and the geo-accumulation index (Igeo) indicated that Cu, Co, Ni, and Cr were not at pollution levels, while Pb, Zn, and Cd indicated moderate contamination. Compared with sediment quality guidelines (SQGs), Cu, Zn, Cr, Pb, and Cd were likely to produce occasional adverse biological effects, while Ni showed possible ecotoxicological risks. The combined levels of the metals have a 21% probability of being toxic. PMID:26362454

  14. Central collisions of heavy ions. Progress report, October 1, 1992--August 31, 1993

    SciTech Connect

    Fung, Sun-yiu

    1993-08-01

    This report describes the activities of the Heavy Ion Physics Group at the University of California, Riverside from October 1, 1992 to August 31, 1993. During this period, our AGS E802/E859/E866 experiments focused on strange particle production, and the fluctuation phenomenon associated with correlation studies in nucleus nucleus central collisions. We have designed and are implementing a new detector to replace the Target Multiplicity Array (TMA) for the E866 runs. As part of the PHENIX collaboration, we contributed to the Conceptual Design Report (CDR), and worked on a RHIC silicon microstrip detector R&D project, the central core of the multiplicity-vertex detector (MVD). In the coming year, we planned to complete the New Multiplicity Array (NMA) detector for the gold projectile E866 experiment, and analyzed the data associated with this new system. We are continuing our efforts in the preparation of the PHENIX detector system.

  15. Using dynamical downscaling to examine mechanisms contributing to the intensification of Central U.S. heavy rainfall events

    NASA Astrophysics Data System (ADS)

    Harding, Keith J.; Snyder, Peter K.

    2015-04-01

    The frequency and intensity of heavy rainfall events have increased in the Central U.S. over the last several decades, and model projections from dynamical downscaling suggest a continuation with climate change. In this study, we examine how climate change might affect mechanisms related to the development of heavy rainfall events that occur on the scale of mesoscale convective systems over the Central U.S. To accomplish these goals, we incorporate dynamical downscaled simulations of two Coupled Model Intercomparison Project phase 5 models in the Weather Research and Forecasting model that accurately simulate heavy rainfall events. For each model, a set of heavy rainfall events that match the frequency, timing, and intensity of observed events are objectively identified in historical and future simulations. We then examine multimodel composites of select atmospheric fields during these events in simulations of historical and future scenarios, enabling an identification of possible physical mechanisms that could contribute to the intensification of heavy rainfall events with climate change. Simulations show that additional moisture is transported into convective updrafts during heavy rain events in future simulations, driving stronger evaporative cooling from the entrainment of drier midtropospheric air. This results in the formation of a stronger low-level cold pool, which enhances moisture convergence above the cold pool and increases rainfall rates during future heavy precipitation events. In addition, a warmer profile in future simulations might allow for heavier rainfall rates as a deeper atmospheric column can support additional collision-coalescence of liquid hydrometeors.

  16. Evaluate the radioactivity along the central thimble hole of a decommissioned heavy water research reactor using TLD approach.

    PubMed

    Lee, Lun-Hui; Sher, Hai-Feng; Lu, I-Hsin; Pan, Lung-Kwang

    2012-04-01

    The radioactivity along the central thimble hole of a decommissioned heavy water research reactor, TRR, was evaluated using TLD approach. The decay radionuclide was verified to be Co-60. The dose along the TRR central thimble hole was detected and revised by performing an unfolding analysis. The revised data reduced to 70-90% of the original data (for example, the maximum dose rate was reduced from 6447 to 4831 mSv/h,) and were more reliable. PMID:22197461

  17. Neutron diffraction study of magnetic field induced behavior in the heavy Fermion Ce3Co4Sn13

    SciTech Connect

    Christianson, Andrew D; Goremychkin, E. A.; Gardner, J. S.; Kang, H. J.; Chung, J.-H.; Manuel, P.; Thompson, J. D.; Sarrao, J. L.; Lawrence, J. M.

    2008-01-01

    The specific heat of Ce3Co4Sn13 exhibits a crossover from heavy Fermion behavior with antiferromagnetic correlations at low field to single impurity Kondo behavior above 2 T. We have performed neutron diffraction measurements in magnetic fields up to 6 Tesla on single crystal samples. The (001) position shows a dramatic increase in intensity in field which appears to arise from static polarization of the 4f level and which at 0.14 K also exhibits an anomaly near 2T reflecting the crossover to single impurity behavior.

  18. Three-dimensional circulation structures leading to heavy summer rainfall over central North China

    NASA Astrophysics Data System (ADS)

    Sun, Wei; Yu, Rucong; Li, Jian; Yuan, Weihua

    2016-04-01

    Using daily and hourly rain gauge records and Japanese 25 year reanalysis data over 30 years, this work reveals two major circulation structures leading to heavy summer rainfall events in central North China (CNC), and further analyzes the effects of the circulations on these rainfall events. One circulation structure has an extensive upper tropospheric warm anomaly (UTWA) covering North China (NC). By strengthening the upper anticyclonic anomaly and lower southerly flows around NC, the UTWA plays a positive role in forming upper level divergence and lower level moisture convergence. As a result, the warm anomalous circulation has a solid relationship with large-scale, long-duration rainfall events with a diurnal peak around midnight to early morning. The other circulation structure has an upper tropospheric cold anomaly (UTCA) located in the upper stream of NC. Contributed to by the UTCA, a cold trough appears in the upper stream of NC and an unstable configuration with upper (lower) cold (warm) anomalies forms around CNC. Consequently, CNC is covered by strong instability and high convective energy, and the cold anomalous circulation is closely connected with local, short-duration rainfall events concentrated from late afternoon to early nighttime. The close connections between circulation structures and typical rainfall events are confirmed by two independent converse analysis processes: from circulations to rainfall characteristics, and from typical rainfall events to circulations. The results presented in this work indicate that the upper tropospheric temperature has significant influences on heavy rainfall, and thus more attention should be paid to the upper tropospheric temperature in future analyses.

  19. Two major circulation structures leading to heavy summer rainfall over central North China

    NASA Astrophysics Data System (ADS)

    Sun, Wei; Li, Jian; Yu, Rucong; Yuan, Weihua

    2015-05-01

    Using daily and hourly rain gauge records and Japanese 25 year reanalysis data over 30 years, this paper reveals two major circulation structures leading to heavy summer rainfall events in central North China (CNC), and further analyzes the effects of the circulations on these rainfall events. One circulation structure has an extensive upper tropospheric warm anomaly (UTWA) covering North China (NC). By strengthening the upper anticyclonic anomaly and lower southerly flows around NC, the UTWA plays a positive role in forming upper level divergence and lower level moisture convergence. As a result, the warm anomalous circulation has a solid relationship with large-scale, long-duration rainfall events with a diurnal peak around midnight to early morning. The other circulation structure has an upper tropospheric cold anomaly (UTCA) located in the upper stream of NC. Contributed to by the UTCA, a cold trough appears in the upper stream of NC and an unstable configuration with upper (lower) cold (warm) anomalies forms around CNC. Consequently, CNC is covered by strong instability and high convective energy, and the cold anomalous circulation is closely connected with local, short-duration rainfall events concentrated from late afternoon to early nighttime. The close connections between circulation structures and typical rainfall events are confirmed by two independent converse analysis processes: from circulations to rainfall characteristics, and from typical rainfall events to circulations. The results presented in this paper indicate that the upper tropospheric temperature has significant influences on heavy rainfall, and thus more attention should be paid to the upper tropospheric temperature in future analyses.

  20. External Heavy-Atom Effect via Orbital Interactions Revealed by Single-Crystal X-ray Diffraction.

    PubMed

    Sun, Xingxing; Zhang, Baicheng; Li, Xinyang; Trindle, Carl O; Zhang, Guoqing

    2016-07-28

    Enhanced spin-orbit coupling through external heavy-atom effect (EHE) has been routinely used to induce room-temperature phosphorescence (RTP) for purely organic molecular materials. Therefore, understanding the nature of EHE, i.e., the specific orbital interactions between the external heavy atom and the luminophore, is of essential importance in molecular design. For organic systems, halogens (e.g., Cl, Br, and I) are the most commonly seen heavy atoms serving to realize the EHE-related RTP. In this report, we conduct an investigation on how heavy-atom perturbers and aromatic luminophores interact on the basis of data obtained from crystallography. We synthesized two classes of molecular systems including N-haloalkyl-substituted carbazoles and quinolinium halides, where the luminescent molecules are considered as "base" or "acid" relative to the heavy-atom perturbers, respectively. We propose that electron donation from a π molecular orbital (MO) of the carbazole to the σ* MO of the C-X bond (π/σ*) and n electron donation to a π* MO of the quinolinium moiety (n/π*) are responsible for the EHE (RTP) in the solid state, respectively. PMID:27319778

  1. Sediment evidence of early eutrophication and heavy metal pollution of Lake Mälaren, central Sweden.

    PubMed

    Renberg, I; Bindler, R; Bradshaw, E; Emteryd, O; McGowan, S

    2001-12-01

    Lake Mälaren is the water supply and recreation area for more than 1 million people in central Sweden and subject to considerable environmental concern. To establish background data for assessments of contemporary levels of trophy and heavy metal pollution, sediment cores from the lake were analyzed. Diatom-inferred lake-water phosphorus concentrations suggest that pre-20th century nutrient levels in Södra Björkfjärden, a basin in the eastern part of Mälaren, were higher (c. 10-20 micrograms TP L-1) than previously assumed (c. 6 micrograms TP L-1). Stable lead isotope and lead concentration analyses from 3 basins (S. Björkfjärden, Gisselfjärden and Asköfjärden) show that the lake was polluted in the 19th century and earlier from extensive metal production and processing in the catchment, particularly in the Bergslagen region. The lake has experienced a substantial improvement of the lead pollution situation in the 20th century following closure of the mining and metal industry. The lead pollution from the old mining industry was large compared to late-20th century pollution from car emissions, burning of fossil fuels and modern industries. PMID:11878023

  2. Crystallization and preliminary X-ray diffraction analysis of central structure domains from mumps virus F protein

    SciTech Connect

    Liu, Yueyong; Xu, Yanhui; Zhu, Jieqing; Qiu, Bingsheng; Rao, Zihe; Gao, George F.; Tien, Po

    2005-09-01

    Single crystals of the central structure domains from mumps virus F protein have been obtained by the hanging-drop vapour-diffusion method. A diffraction data set has been collected to 2.2 Å resolution. Fusion of members of the Paramyxoviridae family involves two glycoproteins: the attachment protein and the fusion protein. Changes in the fusion-protein conformation were caused by binding of the attachment protein to the cellular receptor. In the membrane-fusion process, two highly conserved heptad-repeat (HR) regions, HR1 and HR2, are believed to form a stable six-helix coiled-coil bundle. However, no crystal structure has yet been determined for this state in the mumps virus (MuV, a member of the Paramyxoviridae family). In this study, a single-chain protein consisting of two HR regions connected by a flexible amino-acid linker (named 2-Helix) was expressed, purified and crystallized by the hanging-drop vapour-diffusion method. A complete X-ray data set was obtained in-house to 2.2 Å resolution from a single crystal. The crystal belongs to space group C2, with unit-cell parameters a = 161.2, b = 60.8, c = 40.1 Å, β = 98.4°. The crystal structure will help in understanding the molecular mechanism of Paramyxoviridae family membrane fusion.

  3. Investigation of the Evolution of Central Defects in Ultra-Heavy Plate Rolled Using Gradient Temperature Process

    NASA Astrophysics Data System (ADS)

    Gaosheng, Li; Wei, Yu; Qingwu, Cai

    2015-04-01

    To eliminate flaws, such as shrinkage, porosity, and micro-cracks, in heavy plates, the slab or ingot needs to be subjected to a sufficiently large cumulative reduction in central area. Traditionally, a large slab size is considered to be necessary for thick plate rolling. The evolution of central cracks in heavy plate was investigated by finite element modeling using two different rolling processes: gradient temperature rolling (GTR) with 1073 K (800 °C) on the surface and 1373 K (1100 °C) in the core, and uniform temperature rolling (UTR). The results of simulation were confirmed by clad rolling experiments. Results reveal that, using GTR, the central crack closes easily because of increased central strain and stress. Clad plate produced by GTR has a good bonding interface and fine microstructure. Ferrite grains in GTR plate are refined to 22 µm and the quarter- and half thickness impact energies are increased by 25.8 and 50.1 pct, respectively, compared with UTR plate, the properties of central layer decrease slightly, compared with those of the base materials.

  4. Benthic foraminifera for heavy metal pollution monitoring: A case study from the central Adriatic Sea coast of Italy

    NASA Astrophysics Data System (ADS)

    Frontalini, F.; Coccioni, R.

    2008-01-01

    Benthic foraminifera are increasingly used as environmental bio-indicators of pollution in coastal and marginal marine settings. Their community structure provides information on the general characteristics of the environment and some species are sensitive to specific environmental parameters. Among various criteria, the occurrence of test abnormalities may represent a useful bioindicator for monitoring environmental impacts in coastal regions. A study of living benthic foraminifera was carried out in 42 sediment samples collected from the central Adriatic coast of Italy. Benthic foraminiferal assemblages from this area are rich, well preserved, and dominated by Ammonia parkinsoniana, and subordinately by Ammonia tepida, Aubignyna perlucida, Eggerella scabra, and Nonionella turgida. Heavy metal concentrations have been analysed which indicate low polluted environmental conditions. Foraminiferal species and heavy metal concentrations were investigated both with bivariate (correlation matrix) and multivariate techniques of principal component analysis (PCA) and cluster analysis. Statistical analysis shows a possible control of these pollutants both on the taxonomic composition of the benthic foraminiferal assemblages and the development of test malformations. Increasing heavy metal contents lead to an increase in relative abundance of A. tepida A. perlucida, N. turgida and E. scabra, and a relative concurrent decrease in relative abundance of A. parkinsoniana and higher percentages of deformed specimens (FAI) and species (FMI). Our results confirm that A. parkinsoniana prefers clean to low polluted environments and show that it is a very sensitive and un-tolerant species to heavy metal pollution being deeply affected by heavy metal content even at low concentrations. Our findings also confirm the capacity of the A. tepida to tolerate increasing heavy metal concentrations, and highlights that A. perlucida, N. turgida and E. scabra can be considered as tolerant species

  5. Neutron and X-Ray Diffraction Studies of Magnetic Order in Uranium-Based Heavy Fermion Superconductors

    NASA Astrophysics Data System (ADS)

    Lussier, Jean-Guy

    UPt_3, URu_2 Si_2, UNi_2 Al_3 and UPd_2 Al_3 form a special group among the uranium alloys because they exhibit heavy fermion character, magnetic order and superconductivity. This main interest in the study of this group of compounds resides in the simultaneous occurrence of magnetism and superconductivity at low temperature. Such a state could potentially involve an unconventional superconducting pairing mechanism, different from that contained in standard BCS theory. In this thesis, the magnetic states of three of these materials (URu_2Si _2, UNi_2Al _3 and UPd_2Al _3) is investigated with neutron and the relatively new resonant magnetic X-ray scattering techniques. The work presented here on URu_2Si _2 follows an earlier effort that demonstrated the applicabililty of the resonant X-ray technique to this weak magnetic system. Access to reciprocal space was extended in order to confirm the multipolar form of the resonant X-ray cross-section and to explore the limits of the technique compared to neutron scattering. The situation with the newly discovered UNi_2Al _3 and UPd_2Al _3 was different since their magnetic structure and phases needed first to be established. This task was achieved using two magnetic probes (neutron and X-ray scattering). Several magnetic order parameters in the normal and in the superconducting phase were also measured. The incommensurate magnetic order found in UNi_2Al_3 by neutron scattering constitutes the first observation of long range order in this compound. Other measurements on this compound provided some clues about the evolution of the magnetic structure in high magnetic fields.

  6. Heavy ion reaction measurements with the EOS TPC (looking for central collisions with missing energy)

    SciTech Connect

    Wieman, H.H.; EOS Collaboration

    1994-05-01

    The EOS TPC was constructed for complete event measurement of heavy ion collisions at the Bevalac. We report here on the TPC design and some preliminary measurements of conserved event quantities such as total invariant mass, total momentum, total A and Z.

  7. Masses and magnetic moments of heavy flavour baryons in hyper central model

    NASA Astrophysics Data System (ADS)

    Patel, Bhavin; Raiyz, Ajay Kumar; Vinodkumar, P. C.

    2008-05-01

    We employ the hyper central approach to study the masses and magnetic moments of the baryons constituting single charm and beauty quark. The confinement potential is assumed in the hyper central co-ordinates of the coulomb plus power potential form.

  8. Heavy metal and organochlorine compound concentrations in tissues of raccoons from east-central Michigan

    SciTech Connect

    Herbert, G.B.; Peterle, T.J. )

    1990-02-01

    Organochlorine (OC) pesticides and related compounds and heavy metals are persistent contaminants in the environment. Bioconcentration and biomagnification are well reported for organochlorine compounds. These compounds have a great potential for causing wildlife mortality or serious behavioral, reproductive, carcinogenic, teratogenic, and mutagenic effects, along with specific organ toxicity. The pervasive nature of toxic substances in the environment necessitates some knowledge for potential exposure of wildlife species. Without baseline values of contaminant loads for selected indicator species it is impossible to determine when abnormal or pathological conditions exist in wild populations. The purpose of this study was to provide baseline values for selected environmental contaminants in the raccoon (Procyon lotor), a potential indicator species for wildlife and to see if heavy metal accumulation was related to age or sex.

  9. Ecotoxicological hazard and risk assessment of heavy metal contents in agricultural soils of central Germany.

    PubMed

    Manz, M; Weissflog, L; Kühne, R; Schürmann, G

    1999-02-01

    Heavy metal content of agricultural topsoils has been experimentally determined at 14 areas in the German Leipzig-Halle-Bitterfeld region covering ca. 3700 km2. For most of the locations and elements, the contamination levels are comparable to those of other agricultural sites in Germany and Europe. Application of a sequential extraction technique revealed relatively low contamination levels in the mobile fractions, which indicates a correspondingly low degree of bioavailability of the heavy metals under the current milieu conditions. In contrast, acidification of the soil due to a drastic decrease in the deposition of calciferous fly ash would lead to a significantly increased ecotoxicological hazard potential, as is analyzed by a probabilistic distribution method that quantifies the overlap of normalized exposure and effect data. The discussion includes recommendations for further improvement of risk assessment schemes addressing soil contamination. PMID:10051370

  10. Relationships between magnetic susceptibility and heavy metals in urban topsoils in the arid region of Isfahan, central Iran

    NASA Astrophysics Data System (ADS)

    Karimi, Rezvan; Ayoubi, Shamsollah; Jalalian, Ahmad; Sheikh-Hosseini, Ahmad Reza; Afyuni, Majid

    2011-05-01

    Recently methods dealing with magnetometry have been proposed as a proper proxy for assessing the heavy metal pollution of soils. A total of 113 topsoil samples were collected from public parks and green strips along the rim of roads with high-density traffic within the city of Isfahan, central Iran. The magnetic susceptibility (χ) of the collected soil samples was measured at both low and high frequency (χlf and χhf) using the Bartington MS2 dual frequency sensor. As, Cd, Cr, Ba, Cu, Mn, Pb, Zn, Sr and V concentrations were measured in the all collected soil samples. Significant correlations were found between Zn and Cu (0.85) and between Zn and Pb (0.84). The χfd value of urban topsoil varied from 0.45% to 7.7%. Low mean value of χfd indicated that the magnetic properties of the samples are predominately contributed by multi-domain grains, rather than by super-paramagnetic particles. Lead, Cu, Zn, and Ba showed positive significant correlations with magnetic susceptibility, but As, Sr, Cd, Mn, Cr and V, had no significant correlation with the magnetic susceptibility. There was a significant correlation between pollution load index (PLI) and χlf. PLI was computed to evaluate the soil environmental quality of selected heavy metals. Moreover, the results of multiple regression analysis between χlf and heavy metal concentrations indicated the LnPb, V and LnCu could explain approximately 54% of the total variability of χlf in the study area. These results indicate the potential of the magnetometric methods to evaluate the heavy metal pollution of soils.

  11. Interference from the Robledo DSN Transmitters to Central Madrid IMT-2000/UMTS System through Terrain Diffraction at S-Band

    NASA Technical Reports Server (NTRS)

    Ho, Christian M.; Sue, Miles K.; Peng, Ted K.; Smith, Ernest K.

    2002-01-01

    This study evaluates the possible interference from DSN Robledo 70-m transmitter with Madrid IMT-2000/UMTS wireless users in Spain as both systems will share the same frequency band. Using the effective earth radius, the 50 km terrain profile between Robledo and Madrid is modified and reconstructed. The diffraction propagation losses due to mountain peaks are calculated for the receivers in Madrid urban area. The mountains along the path are simplified into a rounded knife-edge and a rounded obstacle. The results show that for a near surface receiver (1.5 m above the ground) in Madrid, interference signal powers received are less than -135 dBm, which is far below the -109 dBm, the IMT-2000 wireless phone threshold. When a receiver is located at about 40 m above the ground (e.g., the top of Clock Tower of Cibeles Palace), diffraction will generate interference power less than -115 dBm. We find that our calculation results are basically consistent with those from the Longley-Rice model, while the latter has smaller loss because of the low resolution terrain profile used. As a comparison, we also find that the measurements of interference powers of -121.2 dBm at the top of Clock tower is in the range of the estimation. We conclude that the interference through the diffraction mechanism will not cause any problem to IMT-2000/UMTS users at near the surface of Madrid urban area.

  12. Model investigation on the probability of QGP formation at different centralities in relativistic heavy ion collisions

    SciTech Connect

    Yu Meiling; Xu Mingmei; Liu Lianshou; Liu Zhengyou

    2009-12-15

    The quantitative dependence of quark-gluon plasma (QGP)-formation probability (P{sub QGP}) on the centrality of Au-Au collisions is studied using a bond percolation model. The P{sub QGP} versus the maximum distance S{sub max} for a bond to form is calculated from the model for various nuclei and the P{sub QGP} at different centralities of Au-Au collisions for the given S{sub max} are obtained therefrom. The experimental data of the nuclear modification factor R{sub AA}(p{sub T}) for the most central Au-Au collisions at {radical}(s{sub NN})=200 and 130 GeV are utilized to transform S{sub max} to {radical}(s{sub NN}). The P{sub QGP} for different centralities of Au-Au collisions at these two energies are thus obtained, which is useful for correctly understanding the centrality dependence of the experimental data.

  13. Assessment of factors related to heavy metals distribution in abandoned mining soils in Madrid, central Spain

    NASA Astrophysics Data System (ADS)

    Torres, Manuel; Carral, Pilar; Alvarez, Ana M.; Hernández, Zulimar; Lorena, Recio-Vázquez; Marques, Maria J.; Almendros, Gonzalo

    2013-04-01

    Exploitation of metallic mineral deposits and its subsequent abandonment in last decades has lead to significant environmental hazard for natural systems. The present study concerns the distribution and mobility of heavy metals and trace elements mainly As, Cu, Cd, Co, Mn and V, in sulphide-rich soils. The site studied (Sierra de Guadarrama, Garganta de los Montes, Madrid) is at 1200 m asl. Soils are Humic and Dystric Cambisols (WRB) developed on gneisses; the main minerals consist of sulphides and include chalcopyrite, pyrite, marcasite, galena and arsenopyrite. Concentration data of the different species of heavy metals as dependent variables in addition to a series of independent variables mainly soil organic matter were subjected to multivariate chemometric treatments including multidimensional scaling (MDS), principal component analysis (PCA) and support vector machine (SVM) for a preliminary survey on the possible role of soil organic matter in the distribution and speciation of heavy metals in soils. The soil heavy metals speciation was determined using the BCR (Community Bureau of Reference, European Commission) sequential extraction procedure and analysed by ICP-MS. The total contents of these elements were calculated as the sum of the four BCR fractions. The results showed element concentrations decreasing with the distance from the source of pollution. The highest amounts of As and Mn, and Cu, Cd, Co and V were found at 10 and 100 m respectively. These values exceed the allowed limits of the environmental regulation. The percentages of extractable elements (step one of BCR) in relation to total elements show that Cu and Cd were significantly more easily extractable than the other elements. Metal availability in soils was generally controlled by total metal concentration. Data processing techniques coincided in pointing out the association of high levels of organic matter with the concentrations of elements extracted just in the most available forms: i

  14. Radioactivity levels and heavy metals in the urban soil of Central Serbia.

    PubMed

    Milenkovic, B; Stajic, J M; Gulan, Lj; Zeremski, T; Nikezic, D

    2015-11-01

    Radioactivity concentrations and heavy metal content were measured in soil samples collected from the area of Kragujevac, one of the largest cities in Serbia. The specific activities of (226)Ra, (232)Th, (40)K and (137)Cs in 30 samples were measured by gamma spectrometry using an HPGe semiconductor detector. The average values ± standard deviations were 33.5 ± 8.2, 50.3 ± 10.6, 425.8 ± 75.7 and 40.2 ± 26.3 Bq kg(-1), respectively. The activity concentrations of (226)Ra, (232)Th and (137)Cs have shown normal distribution. The annual effective doses, radium equivalent activities, external hazard indexes and excess lifetime cancer risk were also estimated. A RAD7 device was used for measuring radon exhalation rates from several samples with highest content of (226)Ra. The concentrations of As, Co, Cr, Cu, Mn, Ni, Pb and Zn were measured, as well as their EDTA extractable concentrations. Wide ranges of values were obtained, especially for Cr, Mn, Ni, Pb and Zn. The absence of normal distribution indicates anthropogenic origin of Cr, Ni, Pb and Zn. Correlations between radionuclide activities, heavy metal contents and physicochemical properties of analysed soil were determined by Spearman correlation coefficient. Strong positive correlation between (226)Ra and (232)Th was found. PMID:26087932

  15. Radial space potential measurements in the central cell of the tandem mirror experiment with a heavy-ion-beam probe

    SciTech Connect

    Hallock, G.A.

    1983-04-11

    Spatial and temporal profiles of the space potential in the central-cell midplane of TMX have been obtained with a heavy-ion-beam probe. The absolute accuracy of measurements is +- 25 volts (with respect to the machine vacuum walls) with a resolution of approx. 2 volts. During moderate fueling with the gas boxes (i/sub gas/ approx. = 1200 Atom-Amperes D/sub 2/), the plasma potential is parabolic to at least 25 cm radius, with phi/sub e/ approx. = phi/sub max/(1-(r/32)/sup 2/) and 300 < phi/sub max/ <450 volts. With puffer-valve fueling, the space potential is relatively flat to at least 27 cm radius, with 250 < phi/sub e/ < 350 volts.

  16. Field Dependence of the Magnetic Propagation Vector of the Heavy Fermion Compound CeCu2Ge2 Studied by Neutron Diffraction

    NASA Astrophysics Data System (ADS)

    Loewenhaupt, M.; Geselbracht, P.; Faulhaber, E.; Rotter, M.; Doerr, M.; Schmalzl, K.; Schneidewind, A.

    CeCu2Ge2, the counterpart of the heavy-fermion superconductor CeCu2Si2, exhibits an in-commensurate antiferromagnetically long-range ordered ground state with τ = (0.28 0.28 0.54) below TN = 4.15K. The magnetism is strongly affected by a Kondo screening of the Ce 4f-moments by conduction electrons. The similar energy scale of both, Kondo and exchange interactions, results in a complex magnetic phase diagram and gives rise to potential quantum critical phenomena at very low temperatures. We present elastic neutron diffraction data obtained on a CeCu2Ge2 single crystal employing the cold triple axis spectrometer PANDA at MLZ and the diffractometer D23 at ILL. The field dependence of the magnetic propagation vector was measured at T ≤ 400 mK in the [110]/[001] plane with vertical magnetic fields applied along [1¯10]. We observe a low-field incommensurate magnetic phase AF1, a first order phase transition around 7.8 T with the coexistence of two phases AF1 and AF2 with slightly different propagation vectors, the disappearance of AF1 at 8 T and the existence of AF2 up to 12 T with a possible modification at 10 T. At 12.6 T, yet still well below the value of 26 T of the saturation for magnetic fields in [110] direction, the AF2-type magnetic order is lost and magnetic intensities are not to be found at incommensurate positions in the [110]/[001] plane any more. These new results contradict a previously suggested scenario with a QCP located at 8 T and contribute new information to the B - T phase diagram of CeCu2Ge2 in [110] direction.

  17. Heavy metal geochemistry of the acid mine drainage discharged from the Hejiacun uranium mine in central Hunan, China

    NASA Astrophysics Data System (ADS)

    Peng, Bo; Tang, Xiaoyan; Yu, Changxun; Xie, Shurong; Xiao, Meilian; Song, Zhi; Tu, Xianglin

    2009-03-01

    The acid mine drainage (AMD) discharged from the Hejiacun uranium mine in central Hunan (China) was sampled and analyzed using ICP-MS techniques. The analyzing results show that the AMD is characterized by the major ions FeTotal, Mn, Al and Si, and is concentrated with heavy metals and metalloids including Cd, Co, Ni, Zn, U, Cu, Pb, Tl, V, Cr, Se, As and Sb. During the AMD flowing downstream, the dissolved heavy metals were removed from the AMD waters through adsorption onto and co-precipitation with metal-oxhydroxides coated on the streambed. Among these metals, Cd, Co, Ni, Zn, U, Cu, Pb and Tl are negatively correlated to pH values, and positively correlated to major ions Fe, Al, Si, Mn, Mg, Ca and K. The metals/metalloids V, Cr, Se, As and Sb are conservative in the AMD solution, and negatively-correlated to major ions Na, Ca and Mg. Due to the above different behaviors of these chemical elements, the pH-negatively related metals (PM) and the conservative metals (CM) are identified; the PM metals include Cd, Co, Ni, Zn, U, Cu, Pb and Tl, and the CM metals V, Cr, Se, As and Sb. Based on understanding the geochemistry of PM and CM metals in the AMD waters, a new equation: EXT = (Acidity + PM)/pH + CM × pH, is proposed to estimate and evaluate extent of heavy-metal pollution (EXT) of AMD. The evaluation results show that the AMD and surface waters of the mine area have high EXT values, and they could be the potential source of heavy-metal contamination of the surrounding environment. Therefore, it is suggested that both the AMD and surface waters should be treated before they are drained out of the mine district, for which the traditional dilution and neutralization methods can be applied to remove the PM metals from the AMD waters, and new techniques through reducing the pH value of the downstream AMD waters should be developed for removal of the CM metals.

  18. Numerical simulations of heavy rainfall over central Korea on 21 September 2010 using the WRF model

    NASA Astrophysics Data System (ADS)

    Byun, Ui-Yong; Hong, Jinkyu; Hong, Song-You; Shin, Hyeyum Hailey

    2015-06-01

    On 21 September 2010, heavy rainfall with a local maximum of 259 mm d-1 occurred near Seoul, South Korea. We examined the ability of the Weather Research and Forecasting (WRF) model in reproducing this disastrous rainfall event and identified the role of two physical processes: planetary boundary layer (PBL) and microphysics (MPS) processes. The WRF model was forced by 6-hourly National Centers for Environmental Prediction (NCEP) Final analysis (FNL) data for 36 hours form 1200 UTC 20 to 0000 UTC 22 September 2010. Twenty-five experiments were performed, consisting of five different PBL schemes—Yonsei University (YSU), Mellor-Yamada-Janjic (MYJ), Quasi Normal Scale Elimination (QNSE), Bougeault and Lacarrere (BouLac), and University of Washington (UW)—and five different MPS schemes—WRF Single-Moment 6-class (WSM6), Goddard, Thompson, Milbrandt 2-moments, and Morrison 2-moments. As expected, there was a specific combination of MPS and PBL schemes that showed good skill in forecasting the precipitation. However, there was no specific PBL or MPS scheme that outperformed the others in all aspects. The experiments with the UW PBL or Thompson MPS scheme showed a relatively small amount of precipitation. Analyses form the sensitivity experiments confirmed that the spatial distribution of the simulated precipitation was dominated by the PBL processes, whereas the MPS processes determined the amount of rainfall. It was also found that the temporal evolution of the precipitation was influenced more by the PBL processes than by the MPS processes.

  19. Relationships between soil heavy metal pollution and enzyme activities in mining areas of northern Hunan province, Central South China

    NASA Astrophysics Data System (ADS)

    Hu, Xue-Feng; Jiang, Ying; Shu, Ying

    2014-05-01

    Hunan province, Central South China, is a well-known nonferrous metal base in China. Mine exploiting and processing there, however, often lead to heavy metal pollution of farmland. To study the effects of mining activities on the soil environmental quality, four representative paddy fields, the HSG, SNJ, NT and THJ, in Y county, northern Hunan province, were investigated. It was found that the streams running through the HSG, SNJ and NT are severely contaminated due to the long-term discharge of untreated mineral wastewater from local indigenous mining factories. The stream at the HSG, for example, is brownish red in color, with high concentrations of Cu, Zn, Cd, Fe and Mn. The concentrations of Cu, Zn and Cd in all the stream water of the HSG, SNJ and NT exceed the maximum allowable levels of the Agricultural Irrigation Water Criteria of China. Correspondingly, the HSG, SNJ and NT are heavily polluted by Cu, Zn and Cd due to the long-term irrigation with the contaminated stream water. In comparison, both stream water and paddy fields of the THJ, far away from mining areas, are not contaminated by any heavy metals and hence regarded as a control in this study. The rice grain produced at the HSG, SNJ and NT has a high risk of Cd contamination. The rate of rice grain produced in the four paddy fields in Y county with Cd exceeding the safe level (Cd, 0.2 μg g-1) specified by the National Standards for Rice Quality and Safety of China reaches 90%. Cd content in the rice grain is positively significantly correlated with that in the paddy fields, especially with the content of diethylenetriaminepentaacetic acid (DTPA) - extracted Cd, suggesting that the heavy metal pollution of paddy fields has already posed a high risk to rice safety and human health. Soil enzyme activities and microbial biomass are significantly inhibited by the heavy metal pollution of the paddy fields. Microbial biomass C and N (MBC and MBN) at a severely contaminated site of the HSG are only 31

  20. UrQMD Calculations of Hbt Correlations in Central Heavy-Ion Collisions at Lhc

    NASA Astrophysics Data System (ADS)

    Li, Q. F.; Gräf, G.; Bleicher, M.

    2013-11-01

    Two-pion Hanbury-Brown-Twiss (HBT) correlations for central Pb-Pb collisions at the Large-Hadron-Collider (LHC) energy of √ {sNN} = 2.76 TeV are investigated with the cascade mode of the microscopic transport model UrQMD (Ultra-relativistic Quantum Molecular Dynamics). The transverse momentum dependence of the HBT radii is extracted from a three dimensional Gaussian fit to the correlator in the longitudinal co-moving system (LCMS). Qualitative agreement with the ALICE data is obtained, however Rout is overpredicted by nearly 50%. The LHC results are also compared to data from the STAR experiment at RHIC. For both energies we find that the calculated RO/RS ratio is always larger than data, indicating that the emission in the model is less explosive than observed in the data.

  1. NMR imaging and spectroscopy of the mammalian central nervous system after heavy ion radiation

    SciTech Connect

    Richards, T.

    1984-09-01

    NMR imaging, NMR spectroscopic, and histopathologic techniques were used to study the proton relaxation time and related biochemical changes in the central nervous system after helium beam in vivo irradiation of the rodent brain. The spectroscopic observations reported in this dissertation were made possible by development of methods for measuring the NMR parameters of the rodent brain in vivo and in vitro. The methods include (1) depth selective spectroscopy using an optimization of rf pulse energy based on a priori knowledge of N-acetyl aspartate and lipid spectra of the normal brain, (2) phase-encoded proton spectroscopy of the living rodent using a surface coil, and (3) dual aqueous and organic tissue extraction technique for spectroscopy. Radiation induced increases were observed in lipid and p-choline peaks of the proton spectrum, in vivo. Proton NMR spectroscopy measurements on brain extracts (aqueous and organic solvents) were made to observe chemical changes that could not be seen in vivo. Radiation-induced changes were observed in lactate, GABA, glutamate, and p-choline peak areas of the aqueous fraction spectra. In the organic fraction, decreases were observed in peak area ratios of the terminal-methyl peaks, the N-methyl groups of choline, and at a peak at 2.84 ppM (phosphatidyl ethanolamine and phosphatidyl serine resonances) relative to TMS. With histology and Evans blue injections, blood-brain barrier alternations were seen as early as 4 days after irradiation. 83 references, 53 figures.

  2. Availability of geogenic heavy metals in soils of Thiva town (central Greece).

    PubMed

    Kelepertzis, Efstratios; Stathopoulou, Eleni

    2013-11-01

    Potentially toxic metals in the urban chemical environment impose risks to both ecosystem and human health. Here, we evaluate the labile pools and availabilities of non-anthropogenic Ni, Cr, Co and Mn in soil samples from Thiva town (central Greece) and investigate their associations with common soil properties and geochemical data obtained by the aqua regia and single selective dissolutions. Experimental work included the initial application of the sequential extraction protocol proposed by the European Community Bureau of Reference and chemical extractions with ethylenediamine tetraacetic acid solution and a modified physiologically based extraction test with the aim to obtain the operationally defined fractions of plant availability and human bioaccessibility, respectively. The leachate results demonstrated that despite the significant contribution of residual metal species especially for Ni and Cr, the studied serpentine soils provide chemically labile pools for all the considered elements. Nickel was found to be the most available metal with the order being Ni > Cr ∼ Co ∼ Mn for plant uptake and Ni > Cr > Co ∼ Mn for human bioaccessibility. The aqua regia extractable concentrations are not predictors of elemental availabilities except for Ni bioaccessible data interpreting however only a moderate percentage of the total variance. The incorporation of basic soil properties (mostly total organic carbon), geochemical data for the major elements Ca, Mg and Fe and ammonium oxalate extractable Cr significantly improved the estimations for individual elements entailing the strong influence of the chemistry and mineralogy of soil materials to the release of focus metals from the soil matrix. This study provides for the first time bioaccessible data for serpentine-derived soils that are more realistic for evaluating potential adverse effects on the human health. PMID:23754146

  3. Increasing heavy metals in the background atmosphere of central North China since the 1980s: Evidence from a 200-year lake sediment record

    NASA Astrophysics Data System (ADS)

    Wan, Dejun; Song, Lei; Yang, Jinsong; Jin, Zhangdong; Zhan, Changlin; Mao, Xin; Liu, Dongwei; Shao, Yue

    2016-08-01

    Long-term trends of atmospheric compositions are significant for assessing the influence of human activities on the atmosphere and protecting the atmospheric environment. In this study, based on heavy metal concentrations and Pb isotope ratios in a well-dated sediment core from a remote alpine lake in central North China, anthropogenic fluxes of As, Cd, Sb, and Pb were reconstructed and heavy metal evolutions in the atmosphere were revealed in the last 200 years. The heavy metals in the atmosphere were generally natural origins before 1980 A.D. Since the 1980s they began to increase gradually, but they increased the most in the 1990s resulting from rapid developments of rough and high energy-consuming industries in North China. After entering the 21st century the industries still developed rapidly, but the atmospheric Pb ceased increase and the As and Sb even decreased in the 2000s due to (1) phasing out of leaded gasoline and (2) implementing stricter industrial emission standards in 2000 A.D. in China. However, in the 2000s the atmospheric heavy metals still kept at a relatively high level and even likely began to increase again in the 2010s. Considering the lake relatively remote and seldom affected by local human activities, the results likely reflect heavy metal evolutions in the regional background atmosphere of central North China at the annual/decadal timescale in the last 200 years.

  4. Centrality dependence of identified particle elliptic flow in relativistic heavy ion collisions at √{sN N}=7.7 -62.4 GeV

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Bai, X.; Bairathi, V.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Cheng, J.; Cherney, M.; Chisman, O.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, H. Z.; Huang, B.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, Y.; Li, W.; Li, C.; Li, X.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, L.; Ma, Y. G.; Ma, G. L.; Ma, R.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, S.; Raniwala, R.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, X.; Sun, Z.; Sun, Y.; Sun, X. M.; Surrow, B.; Svirida, N.; Szelezniak, M. A.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, F.; Wang, Y.; Wang, G.; Wang, Y.; Wang, J. S.; Wang, H.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xin, K.; Xu, Z.; Xu, H.; Xu, Y. F.; Xu, Q. H.; Xu, N.; Yang, Y.; Yang, C.; Yang, S.; Yang, Y.; Yang, Q.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, Y.; Zhang, S.; Zhang, J.; Zhang, J.; Zhang, Z.; Zhang, X. P.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2016-01-01

    Elliptic flow (v2) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at √{sN N}= 7.7 -62.4 GeV are presented for three centrality classes. The centrality dependence and the data at √{sN N}= 14.5 GeV are new. Except at the lowest beam energies, we observe a similar relative v2 baryon-meson splitting for all centrality classes which is in agreement within 15% with the number-of-constituent quark scaling. The larger v2 for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with a multiphase transport (AMPT) model and fit with a blast wave model.

  5. Centrality and energy dependence of charged-particle multiplicities in heavy ion collisions in the context of elementary reactions

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J. Van; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2006-08-01

    The PHOBOS experiment at the BNL Relativistic Heavy Ion Collider has measured the total multiplicity of primary charged particles as a function of collision centrality in Au+Au collisions at sNN= 19.6, 130, and 200 GeV. An approximate independence of / on the number of participating nucleons is observed, reminiscent of “wounded nucleon” scaling (Nch∝Npart) observed in proton-nucleus collisions. Unlike p+A, the constant of proportionality does not seem to be set by the pp/p¯p data at the same energy. Rather, there seems to be a surprising correspondence with the total multiplicity measured in e+e- annihilations, as well as the rapidity shape measured over a large range. The energy dependence of the integrated multiplicity per participant pair shows that e+e- and A+A data agree over a large range of center-of-mass energies (s>20 GeV), and pp/p¯p data can be brought to agree approximately with the e+e- data by correcting for the typical energy taken away by leading particles. This is suggestive of a mechanism for soft particle production that depends mainly on the amount of available energy. It is conjectured that the dominant distinction between A+A and p+p collisions is the multiple collisions per participant, which appears to be sufficient to substantially reduce the energy taken away by leading particles.

  6. Diffractive hard scattering

    SciTech Connect

    Berger, E.L.; Collins, J.C.; Soper, D.E.; Sterman, G.

    1986-03-01

    I discuss events in high energy hadron collisions that contain a hard scattering, in the sense that very heavy quarks or high P/sub T/ jets are produced, yet are diffractive, in the sense that one of the incident hadrons is scattered with only a small energy loss. 8 refs.

  7. Moderate-Heavy Alcohol Consumption Lifestyle in Older Adults Is Associated with Altered Central Executive Network Community Structure during Cognitive Task.

    PubMed

    Mayhugh, Rhiannon E; Moussa, Malaak N; Simpson, Sean L; Lyday, Robert G; Burdette, Jonathan H; Porrino, Linda J; Laurienti, Paul J

    2016-01-01

    Older adults today consume more alcohol than previous generations, the majority being social drinkers. The effects of heavy alcohol use on brain functioning closely resemble age-related changes, but it is not known if moderate-heavy alcohol consumption intensifies brain aging. Whether a lifestyle of moderate-heavy alcohol use in older adults increased age-related brain changes was examined. Forty-one older adults (65-80 years) that consumed light (< 2 drinks/week and ≥ 1 drink/month, n = 20) or moderate-heavy (7-21 drinks/week, non-bingers, n = 21) amounts of alcohol were enrolled. Twenty-two young adults (24-35 years) were also enrolled (light, n = 11 and moderate-heavy, n = 11). Functional brain networks based on magnetic resonance imaging data were generated for resting state and during a working memory task. Whole-brain, Central Executive Network (CEN), and Default Mode Network (DMN) connectivity were assessed in light and moderate-heavy alcohol consuming older adults with comparisons to young adults. The older adults had significantly lower whole brain connectivity (global efficiency) and lower regional connectivity (community structure) in the CEN during task and in the DMN at rest. Moderate-heavy older drinkers did not exhibit whole brain connectivity differences compared to the low drinkers. However, decreased CEN connectivity was observed during the task. There were no differences in the DMN connectivity between drinking groups. Taken together, a lifestyle including moderate-heavy alcohol consumption may be associated with further decreases in brain network connectivity within task-related networks in older adults. Further research is required to determine if this decrease is compensatory or an early sign of decline. PMID:27494180

  8. Moderate-Heavy Alcohol Consumption Lifestyle in Older Adults Is Associated with Altered Central Executive Network Community Structure during Cognitive Task

    PubMed Central

    Moussa, Malaak N.; Simpson, Sean L.; Lyday, Robert G.; Burdette, Jonathan H.; Porrino, Linda J.; Laurienti, Paul J.

    2016-01-01

    Older adults today consume more alcohol than previous generations, the majority being social drinkers. The effects of heavy alcohol use on brain functioning closely resemble age-related changes, but it is not known if moderate-heavy alcohol consumption intensifies brain aging. Whether a lifestyle of moderate-heavy alcohol use in older adults increased age-related brain changes was examined. Forty-one older adults (65–80 years) that consumed light (< 2 drinks/week and ≥ 1 drink/month, n = 20) or moderate-heavy (7–21 drinks/week, non-bingers, n = 21) amounts of alcohol were enrolled. Twenty-two young adults (24–35 years) were also enrolled (light, n = 11 and moderate-heavy, n = 11). Functional brain networks based on magnetic resonance imaging data were generated for resting state and during a working memory task. Whole-brain, Central Executive Network (CEN), and Default Mode Network (DMN) connectivity were assessed in light and moderate-heavy alcohol consuming older adults with comparisons to young adults. The older adults had significantly lower whole brain connectivity (global efficiency) and lower regional connectivity (community structure) in the CEN during task and in the DMN at rest. Moderate-heavy older drinkers did not exhibit whole brain connectivity differences compared to the low drinkers. However, decreased CEN connectivity was observed during the task. There were no differences in the DMN connectivity between drinking groups. Taken together, a lifestyle including moderate-heavy alcohol consumption may be associated with further decreases in brain network connectivity within task-related networks in older adults. Further research is required to determine if this decrease is compensatory or an early sign of decline. PMID:27494180

  9. Phytoremedial assessment of flora tolerant to heavy metals in the contaminated soils of an abandoned Pb mine in Central Portugal.

    PubMed

    Pratas, João; Favas, Paulo J C; D'Souza, Rohan; Varun, Mayank; Paul, Manoj S

    2013-02-01

    Significant accumulation of heavy metals in soils and flora exists around the abandoned Barbadalhos Pb mine in Central Portugal. Soil and plant samples [49 species] were collected from two line transects, LT 1 and LT 2, in the mineralized and non-mineralized area, respectively to gain a comprehensive picture of heavy metals in soils and flora to assess its potential for phytoremediation. Phytosociological inventories of the vegetation were made using the Braun-Blanquet cover-abundance scale. Metal concentrations in soil ranged from (in mg kg(-1)): 98-9330 [Pb], 110-517 [Zn], 7.1-50 [Co], 69-123 [Cr], 31-193 [Cu], 33400-98500 [Fe], 7.7-51 [Ni], 0.95-13 [Ag], 2.8-208 [As], and 71-2220 [Mn] along LT 1; and 24-93 [Pb], 30-162 [Zn], 3.7-34 [Co], 61-196 [Cr], 21-46 [Cu], 24100-59400 [Fe], 17-87 [Ni], 0.71-1.9 [Ag], 4.3-12 [As], and 44-1800 [Mn] along LT 2. Plant metal content ranged from (in mg kg(-1)): 1.11-548 [Pb], 7.06-1020 [Zn], 0.08-2.09 [Co], 0.09-2.03 [Cr], 2.63-38.5 [Cu], 10.4-4450 [Fe], 0.38-8.9 [Ni], and 0.03-1.9 [Ag] along LT 1; and 0.94-11.58 [Pb], 2.83-96.5 [Zn], 0.12-1.44 [Co], 0.21-1.49 [Cr], 1.61-22.7 [Cu], 4.6-2050 [Fe], 0.51-4.81 [Ni], and 0.02-0.31 [Ag] along LT 2. Plants with highest uptake of metals were: Cistus salvifolius (548 mg Pb kg(-1)), Digitalis purpurea (1017 mg Zn kg(-1) and 4450 mg Fe kg(-1)). Mentha suavolens and Ruscus ulmifolius were seen to hyperaccumulate Ag (1.9 and 1 mg Ag kg(-1), respectively). More metals and higher concentrations were traced in plants from LT 1, especially for Pb and Zn. PMID:23098582

  10. Centrality dependence of midrapidity density from GeV to TeV heavy-ion collisions in the effective-energy universality picture of hadroproduction

    NASA Astrophysics Data System (ADS)

    Sarkisyan, Edward K. G.; Mishra, Aditya Nath; Sahoo, Raghunath; Sakharov, Alexander S.

    2016-07-01

    The dependence on centrality, or on the number of nucleon participants, of the midrapidity density of charged particles measured in heavy-ion collisions at the collision energy of about 20 GeV at RHIC to the highest LHC energy of 5 TeV is investigated within the recently proposed effective-energy approach. This approach relates multihadron production in different types of collisions by combining, under the proper scaling of the collision energy, the constituent quark picture with Landau relativistic hydrodynamics. The measurements are shown to be well described based on the similarity of multihadron production process in (anti)proton-proton interactions and heavy-ion collisions driven by the centrality-dependent effective energy of participants.

  11. Concentrated Heavy Rain Detected by InSAR: a Case Study of the August 2008 Episode in Central Japan

    NASA Astrophysics Data System (ADS)

    Kinoshita, Y.; Shimada, M.; Furuya, M.; Hobiger, T.; Ichikawa, R.

    2010-12-01

    Interferometric Synthetic Aperture Radar (InSAR) can measure a spatial distribution of precipitable water vapor with unprecedented spatial resolution, and thus can provide us with unique information about mesoscale weather systems. From the end of August to the beginning of September 2008, torrential rains struck wide areas over central Japan, causing hourly precipitations more than 100 mm at Tokai areas. Japan Aerospace exploration Agency (JAXA) carried out an emergent observation of the heavy rains by PALSAR, an L-band synthetic aperture radar sensor, with an incidence angle of 45 degrees that is different from their nominal operation scenario. On January 2010, JAXA has carried out another PALSAR measurement of the very areas with the same incidence angle as that on 2 September 2008, so that we could generate InSAR image of the area and examine a detailed snapshot of the regional troposphere. Here we report our InSAR observation data, and discuss our preliminary analysis results. Near Ibi River, we could detect localized signals, which changed 12.2 cm in radar line-of-sight over a spatial scale on the order of 8 km, and were unlikely to be an artifact of either DEM errors or ionosphere. We validate this point, showing another InSAR image with similar equivalent spatial baseline as well as azimuth component of pixel-offset data. In addition, we employ a high-resolution numerical weather model, WRF, and a ray-tracing tool, KARAT, so that we could derive the predicted state of troposphere at the moment and compare them with the observation. We will discuss what we can learn from the InSAR image, and what the WRF/KARAT can and cannot predict.

  12. Central exclusive diffractive production of the π+π- continuum, scalar, and tensor resonances in p p and p p ¯ scattering within the tensor Pomeron approach

    NASA Astrophysics Data System (ADS)

    Lebiedowicz, Piotr; Nachtmann, Otto; Szczurek, Antoni

    2016-03-01

    We consider central exclusive diffractive dipion production in the reactions p p →p p π+π- and p p ¯ →p p ¯ π+π- at high energies. We include the dipion continuum, the dominant scalar f0(500 ), f0(980 ) , and tensor f2(1270 ) resonances decaying into the π+π- pairs. The calculation is based on a tensor Pomeron model and the amplitudes for the processes are formulated in terms of vertices respecting the standard crossing and charge-conjugation relations of quantum field theory. The formulas for the dipion continuum and tensor meson production are given here for the first time. The theoretical results are compared with existing STAR, CDF, CMS experimental data and predictions for planned or current experiments (ALICE, ATLAS) are presented. We show the influence of the experimental cuts on the integrated cross section and on various differential distributions for outgoing particles. Distributions in rapidities and transverse momenta of outgoing protons and pions as well as correlations in azimuthal angle between them are presented. We find that the relative contribution of the resonant f2(1270 ) and dipion continuum strongly depends on the cut on proton transverse momenta or four-momentum transfer squared t1 ,2 which may explain some controversial observations made by different ISR experiments in the past. The cuts may play then the role of a π π resonance filter. We suggest some experimental analyses to fix model parameters related to the Pomeron-Pomeron-f2 coupling.

  13. Statistical characteristics of environmental parameters for warm season short-duration heavy rainfall over central and eastern China

    NASA Astrophysics Data System (ADS)

    Tian, Fuyou; Zheng, Yongguang; Zhang, Tao; Zhang, Xiaoling; Mao, Dongyan; Sun, Jianhua; Zhao, Sixiong

    2015-06-01

    Water vapor content, instability, and convergence conditions are the key to short-duration heavy rainfall forecasting. It is necessary to understand the large-scale atmospheric environment characteristics of short-duration heavy rainfall by investigating the distribution of physical parameters for different hourly rainfall intensities. The observed hourly rainfall data in China and the NCEP final analysis (FNL) data during 1 May and 30 September from 2002 to 2009 are used. NCEP FNL data are 6-hourly, resulting in sample sizes of 1573370, 355346, and 11401 for three categories of hourly rainfall ( P) of no precipitation ( P < 0.1 mm h-1), ordinary precipitation (0.1⩽ P < 20 mm h-1), and short-duration heavy rainfall ( P ⩾ 20.0 mm h-1), respectively, by adopting a temporal matching method. The results show that the total precipitable water (PWAT) is the best parameter indicating the hourly rainfall intensity. A PWAT of 28 mm is necessary for any short-duration heavy rainfall. The possibility of short-duration heavy rainfall occurrence increases with PWAT, and a PWAT of 59 mm is nearly sufficient. The specific humidity is a better indicator than relative humidity. Both 700- and 850-hPa relative humidity greater than 80% could be used to determine whether or not it is going to rain, but could not be used to estimate the rainfall intensity. Temperature and potential pseudo-equivalent temperature are also reasonable indicators of short-duration heavy rainfall. Among the atmospheric instability parameters, the best lifted index (BLI) performs best on the short-duration rainfall discrimination; the next best is the K index (KI). The three rainfall categories are not well recognized by total totals (TT) or the temperature difference between 850 and 500 hPa (DT85). Three-quarters of short-duration heavy rainfall occurred with BLI less than -0.9, while no short-duration heavy rainfall occurred when BLI was greater than 2.6. The minimum threshold of KI was 28.1 for short

  14. Centrality dependence of heavy flavor production from single electron measurement in √{S}=200 GeV Au +Au collisions

    NASA Astrophysics Data System (ADS)

    Bielcik, J.; STAR Collaboration

    2006-08-01

    We present preliminary measurements of electron production in p+p, d+Au, and Au+Au collisions at √{S}=200 GeV for transverse momenta 1.5 GeV/ccentrality. These measurements were carried out using the STAR Time Projection Chamber and Barrel Electromagnetic Calorimeter. In this manuscript we describe the measurement techniques used to discriminate electrons from hadrons and the method used to evaluate the non-photonic contributions from semi-leptonic decays of heavy flavor mesons. The observed nuclear modification factors, RAA, of non-photonic electrons indicate at substantial energy loss of heavy quarks at moderate to high pT.

  15. Quantitative geospatial dataset on the near-surface heavy metal concentrations in semi-arid soils from Maibele Airstrip North, Central Botswana.

    PubMed

    Eze, Peter N; Mosokomani, Valiant S; Udeigwe, Theophilus K; Oyedele, Opeoluwa F

    2016-09-01

    This article contains a statistically analyzed dataset of the heavy metals including Cr, Co, Ni, Cu, Zn and Pb contents of near-surface (~30 cm depth) soils in a Cu-Ni prospecting field at Airstrip North, Central Botswana. The soils developed on paragneisses and amphibolites parent materials in a semi-arid environment with hardveld vegetation, "The geology of the Topisi area" (Key et al., 1994) [1]. Grid sampling was adopted in the field data collection. Heavy metals were determined using the relatively new portable x-ray fluorescence spectrometer (Delta Premium, 510,890, USA) technology in a "soil" mode. The data presented was obtained from the average reading of two soil samples collected from same point but passed through sieves. PMID:27617281

  16. Preliminary assessment of heavy metal contamination in surface water and sediments from Honghu Lake, East Central China

    NASA Astrophysics Data System (ADS)

    Hu, Ying; Qi, Shihua; Wu, Chenxi; Ke, Yanping; Chen, Jing; Chen, Wei; Gong, Xiangyi

    2012-03-01

    Heavy metal concentrations in surface water and sediments collected from Honghu Lake in Hubei Province, China were analyzed, and ecological risks were evaluated according to the sediment quality guidelines. The results showed that the average concentrations of heavy metals in surface water were ranked as: As>Zn> Cu>Cr>Pb>Ni>Cd>Hg. In comparison with results reported in other rivers and the background values, The Honghu Lake was polluted by As, Cr, Pb, Cu and Ni. Most of metals might be mainly from fertilizers, industrial effluent and domestic wastewater around the lake. Heavy metals concentrations were relatively higher in the inlet area than in other areas. Negative correlations were observed between most heavy metals and pH, while a significant positive correlation was present between Zn, Cd and Pb. In the sediment core, Cu, Zn, Cr and Ni showed a decreasing trend while Cd present an increasing trend. The decrease of As, Cu, Zn, Cr and Ni in the 1990s might due to the flood event in 1998. The analysis of ecological risk assessment based on sediment quality guidelines suggested that heavy metals in most sediments from the Honghu Lake had moderate toxicity, with Cr being the highest priority pollutant.

  17. Assessment of heavy metal contamination in intertidal gastropod and bivalve shells from central Arabian Gulf coastline, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    El-Sorogy, Abdelbaset S.; Youssef, Mohamed

    2015-11-01

    In order to assess pollutants and impact of environmental changes along the Saudi Arabian Gulf coast, forty specimens of gastropod and bivalve shells belonging to Diodora funiculata, Lunella coronata, Cerithium caeruleum, Barbatia parva, Pinctada margaritifera, Amiantis umbonella, Acrosterigma assimile and Asaphis violascens from five localities are selected for Fe, Cu, Pb, Mn, Cd, Se, As, Co, B, Cr, Hg, Mo analysis. The analysis indicated that heavy metal values (except Fe) were less than those recorded in molluscan shells from Gulf of Oman, Red Sea and Indian Ocean. D. funiculate, L. coronata, B. parva and P. margaritifera are good accumulators of Cu, As, Cr. The other species gave a nearly constant concentration in all the studied areas. Al Jubail coast recorded the highest heavy metal concentrations (except Mn at Ras Al-Ghar and Se at Al Jubail industrial city). Heavy metal contamination is mostly attributed to anthropogenic sources, especially effluents from petrochemical industries, sewage and desalination plants.

  18. Effect of Pressure on Valence and Structural Properties of YbFe2Ge2 Heavy Fermion Compound A Combined Inelastic X-ray Spectroscopy, X-ray Diffraction, and Theoretical Investigation

    SciTech Connect

    Kumar, Ravhi S.; Svane, Axel; Vaitheeswaran, Ganapathy; Kanchana, Venkatakrishnan; Antonio, Daniel; Cornelius, Andrew L.; Bauer, Eric D.; Xiao, Yuming; Chow, Paul

    2015-10-19

    The crystal structure and the Yb valence of the YbFe2Ge2 heavy fermion compound was measured at room temperature and under high pressures using high-pressure powder X-ray diffraction and X-ray absorption spectroscopy via both partial fluorescence yield and resonant inelastic X-ray emission techniques. Furthermore, the measurements are complemented by first-principles density functional theoretical calculations using the self-interaction corrected local spin density approximation investigating in particular the magnetic structure and the Yb valence. While the ThCr2Si2-type tetragonal (I4/mmm) structure is stable up to 53 GPa, the X-ray emission results show an increase of the Yb valence from v = 2.72(2) at ambient pressure to v = 2.93(3) at ~9 GPa, where at low temperature a pressure-induced quantum critical state was reported.

  19. Effect of Pressure on Valence and Structural Properties of YbFe2Ge2 Heavy Fermion Compound--A Combined Inelastic X-ray Spectroscopy, X-ray Diffraction, and Theoretical Investigation.

    PubMed

    Kumar, Ravhi S; Svane, Axel; Vaitheeswaran, Ganapathy; Kanchana, Venkatakrishnan; Antonio, Daniel; Cornelius, Andrew L; Bauer, Eric D; Xiao, Yuming; Chow, Paul

    2015-11-01

    The crystal structure and the Yb valence of the YbFe2Ge2 heavy fermion compound was measured at room temperature and under high pressures using high-pressure powder X-ray diffraction and X-ray absorption spectroscopy via both partial fluorescence yield and resonant inelastic X-ray emission techniques. The measurements are complemented by first-principles density functional theoretical calculations using the self-interaction corrected local spin density approximation investigating in particular the magnetic structure and the Yb valence. While the ThCr2Si2-type tetragonal (I4/mmm) structure is stable up to 53 GPa, the X-ray emission results show an increase of the Yb valence from v = 2.72(2) at ambient pressure to v = 2.93(3) at ∼9 GPa, where at low temperature a pressure-induced quantum critical state was reported. PMID:26479903

  20. Spatial monitoring of arsenic and heavy metals in the Almyros area, Central Greece. Statistical approach for assessing the sources of contamination.

    PubMed

    Golia, E E; Dimirkou, A; Floras, St A

    2015-07-01

    The purpose of this work was to provide information on As and heavy metals content in surface soils of the Almyros area, in Central Greece. A 3-year (2009-2011) research was conducted, in order to investigate the possible temporal variation of As and heavy metal levels. Each year, a number of 251 soil samples (753 totally number of samples) were collected from the area studied, using a Differential Global Positioning System (D.G.P.S.). Soil samples were analyzed for physicochemical parameters and for pseudo-total content of metals, after digestion with Aqua Regia. Thematic maps were created, with Geographic Information Systems (GIS) techniques, using geostatistical tools. The corresponding topographical diagrams covering 15,000 ha of the study area were digitized. The thematic maps and the geostatistical analysis tools were conducted with the use of ArcGIS and the extensions Geostatistical Analyst, Spatial Analyst, and 3D analyst. Factor analysis was conducted in order to assess the possible sources of the pollution. The levels of As and metals determined were lower than the maximum permitted, except for Cd, which content was, in some cases, higher than the critical limits for soils. No statistical differences were observed among the years of the study, although a trend of continuous increasing of their content was detected. Significant correlations between heavy metal fractions and soil physicochemical parameters were obtained and discussed. PMID:26041064

  1. Forward-backward multiplicity correlations caused by centrality fluctuations in high-energy heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    He, Ronghua; Qian, Jing; Huo, Lei

    2016-04-01

    We consider that most of the long-range forward-backward multiplicity (FB) correlations in high energy A -A collisions are caused by the centrality fluctuation, and this phenomenon interferes with the measurement of the dynamical correlations greatly. We investigate the relationship between FB correlation strength and centrality by a Monte Carlo simulation and a derivation which are tested by A MultiPhases Transport (AMPT) model in Au+Au collisions at √{sNN}=200 GeV. We compare the FB correlation strengths of AMPT model with the results of the derivation at √{sNN} = 7.7 to 200 GeV. A comparison between the default AMPT model and string melting AMPT model with different partonic scattering sections is made. As a result, we consider that the FB correlation strengths may be dominated by the mixing of different centrality events, and the short-range correlation may be overwhelmed for the most central collisions.

  2. High-resolution diffraction for residual stress determination in the NiCrMoV wheel of an axial compressor for a heavy-duty gas turbine

    NASA Astrophysics Data System (ADS)

    Rogante, M.; Török, G.; Ceschini, G. F.; Tognarelli, L.; Füzesy, I.; Rosta, L.

    2004-07-01

    The wheel of an axial compressor for a heavy-duty gas turbine has been investigated for residual stresses (RS) evaluation of the teeth-section where SANS measurements have previously been performed. Such a component can contain internal RS, either due to the manufacturing process, or to the operating cycles fatigue. The constitutive material is a NiCrMoV steel to ASTM A 471 (type 2) norms (equivalent to B50A420B10); this material is usually adopted in the manufacturing of forged components for gas turbines. Internal radial and hoop RS have been determined, whose values are under the limit of 200kPa. Hoop RS, in general, resulted in higher value than the radial ones. The present experiment represents a particularly important step in the RS determination for gas turbine components, since the measurements reveal that the fatigue of the wheel is also a lifetime limiting factor although, in the same technological field, the available data in the actual neutron techniques literature mainly concern turbine buckets.

  3. Descriptions of two new and one newly recorded enchytraeid species (Clitellata, Enchytraeidae) from the Ozegahara Mire, a heavy snowfall highmoor in Central Japan.

    PubMed

    Torii, Takaaki

    2015-01-01

    Three species of semi-aquatic freshwater Enchytraeidae of the genera Mesenchytraeus Eisen, 1878, Chamaedrilus Friend, 1913 and Globulidrilus Christensen & Dózsa-Farkas, 2012 are described from stream, wet soil or snow habitats in the Ozegahara Mire, an extensive high moor in heavy snowfall area in central Japan. Among Mesenchytraeus speies, Mesenchytraeus nivalis sp. nov. is distinguished by not having enlarged chaetae and spermathecal diverticula, vas deferens with atrial glands 3 or 4 in number and club-shaped, spermathecal ental duct short, with sperm bundles in the sperm sack. Chamaedrilus ozensis sp. nov. closely resembles C. floridae, but the length of the sperm funnel and character of the coelomocytes are different. Globulidrilus helgei Christensen & Dózsa-Farkas, 2012 is recorded for the first time from Japan. PMID:26623738

  4. Optimization of Mineral Separator for Recovery of Total Heavy Minerals of Bay of Bengal using Central Composite Design

    NASA Astrophysics Data System (ADS)

    Routray, Sunita; Swain, Ranjita; Rao, Raghupatruni Bhima

    2016-01-01

    The present study is aimed at investigating the optimization of a mineral separator for processing of beach sand minerals of Bay of Bengal along Ganjam-Rushikulya coast. The central composite design matrix and response surface methodology were applied in designing the experiments to evaluate the interactive effects of the three most important operating variables, such as feed quantity, wash water rate and Shake amplitude of the deck. The predicted values were found to be in good agreement with the experimental values (R2 = 0.97 for grade and 0.98 for recovery). To understand the impact of each variable, three dimensional (3D) plots were also developed for the estimated responses.

  5. The Potential Impact of Increased Phosphorus Loads in Lakes Acting as Heavy Metal Reservoirs: A case study from west-central Indiana

    NASA Astrophysics Data System (ADS)

    McLennan, D. A.; Latimer, J. C.; Smith, E.; Stone, J.

    2015-12-01

    Green Valley Lake is a designated state fishing area in west-central Indiana. Prior to this designation, the lake was a water supply reservoir for the adjacent and now abandoned Green Valley Coal Mine (Operating from 1948-1963). The Green Valley Coal Mine property continues to produce excess acidity despite reclamation efforts. The former mine property and the lake are connected by a channel that discharges acidic drainage directly into Green Valley Lake. To evaluate temporal variability in metal and phosphorus (P) geochemistry, two short cores were collected in spring 2014 (38cm) and spring 2015 (39cm). Metal concentrations were determined by a hand-held X-ray fluorescence analyzer after the samples had been dried and crushed. Approximately 20% of these metal concentrations will be verified by ICP-OES following extraction in 50% aqua regia. Detailed P geochemistry was determined using a sequential extraction technique (SEDEX). The sediments in Green Valley Lake are characterized by heavy metal concentrations that are elevated above typical background levels. These metals tend to be concentrated near the sediment water interface, often 3-5 times greater than the average concentration for the rest of the core, which suggests that they are diagenetically mobile and possibly diffusing out of the sediments under dysoxic to anoxic conditions and returning to the sediments under oxic conditions. Total sedimentary P averages 57 umol/g, but oscillates between 20 - 110 umol/g. The most dramatic shift in the detailed P geochemistry is the significant reduction of mineral P at 15 cm and the increasing importance of oxide-associated and adsorbed P upcore. Diatom assemblages suggest that the lake has become increasingly more eutrophic over time. As nutrient loads continue to increase, the oxygen depleted zone may expand impacting fish populations and changing water geochemistry significantly, in particular, mobilizing heavy metals.

  6. Passive monitoring of atmospheric heavy metals in a historical city of central India by Lepraria lobificans Nyl.

    PubMed

    Bajpai, Rajesh; Upreti, D K; Dwivedi, S K

    2010-07-01

    Using an organism living in situ for monitoring is referred as passive monitoring. Lepraria lobificans Nyl., a leprose lichen growing naturally on monuments and buildings in the city Mandav in central India is used for passive monitoring of atmospheric metals. Seven metals (Cd, Cr, Ni, Al, Fe, Cu, and Zn) were analyzed. Samples collected from road site exhibit the maximum concentration of Fe, Cd, Cr, Ni, and Zn. Iron exhibit maximum accumulation both in lichen thallus and the substratum with mean values of 2,195.63 microg g(-1) dry weight. As compared with other growth form of lichens, L. lobificans exhibits the higher accumulation of Fe than foliose and fruticose lichens. On the basis of these results, it can be hypothesized that L. lobificans is an excellent accumulator of different metals. The statistical analysis applied to the element concentration between the metals as well as between the sites by analysis of variance found the difference to be significant at 1% and 5%, respectively. Student-Newman-Keuls test also shows significant difference for iron between the different metals. PMID:19496009

  7. Diffractive dijet production in CDF

    SciTech Connect

    Albrow, M.G.; CDF Collaboration

    1998-04-17

    We have studied events with a high-x{sub F} antiproton and two central jets in CDF, with p{anti p} collisions at {radical}s = 630 and 1800 GeV. These events are expected to be dominated by diffraction (pomeron exchange). The jet E{sub T} spectra are very similar to those of non-diffractively produced jets but slightly steeper; their azimuthal difference {Delta}{phi} is more peaked at 180{degree}.

  8. Secondary diffraction of diffracted Gaussian beam of laser radiation

    NASA Astrophysics Data System (ADS)

    Vasil'Ev, Yu. V.; Kozar', A. V.; Matyunin, A. V.

    2011-10-01

    The diffraction of a narrow Gaussian beam of laser radiation on mutually perpendicular edges of crossed, superimposed sharp wedge-shaped blades (safety razors) has been studied. The diffraction pattern observed on a flat screen behind the blades comprises a very bright central spot, which exhibits the structure of a "light network" with rectangular cells, and four groups of narrow bright bands that expand from the central spot toward the periphery and form a rectangular cross. The spatial frequency of light-field modulation on the screen can be controlled by varying the distance from the blades to screen.

  9. Pb isotopes in sediments of Lake Constance, Central Europe constrain the heavy metal pathways and the pollution history of the catchment, the lake and the regional atmosphere

    SciTech Connect

    Kober, B.; Wessels, M.; Bollhoefer, A.; Mangini

    1999-05-01

    Pb isotope ratios and Pb concentrations of well-dated sediments of Lake Constance, Central Europe have been analyzed using thermal ion mass spectrometry. Sequential extraction studies indicated isotope homogeneity of the leachable Pb components within the investigated layers. Since the middle of the 19th century a significant anthropogenic Pb component appeared in the lake sediments, and rapidly approaches concentration levels similar to that of the geogenic Pb background (20 ppm) at the beginning of the 20th century. Anthropogenic Pb was predominantly transferred to the lake sediments via the atmosphere. Pb sources were coal combustion, industrial ore processing and leaded gasoline. The flux of a fluvial Pb component to the lake sediments, additive to atmospheric Pb deposition, peaked in about 1960. This flux is attributed to (re)mobilization of Pb from polluted parts of the lake catchment, and indicates the change of catchment soils from a pollution sink to a heavy metal source. The strong reduction of anthropogenic Pb in the uppermost lake sediments since the 1960s has been caused by advances of environmental protection. The lake sediments record the changing fluxes and the isotope composition of the deposited aeolian Pb pollution. During the 20th century aeolian Pb fluxes to the lake sediments were in the range of 1--4 {micro}g/cm{sup 2}/a. During peak emission periods of gasoline Pb to the atmosphere (1960--1990) the aerosol Pb isotope composition was rather constant ({sup 206}Pb/{sup 207}Pb: 1.12--1.13) and probably a mixture of Canadian and Australian with Russian and Central European Pb types. Aeolian Pb isotope and Pb flux trends in the lake sediments as a whole agree well with the trends found in Alpine glaciers (Doering et al., 1997a,b) and in ombrotrophic peat bogs of Switzerland (Shotyk et al., 1996). However, different industrial Pb components were deposited in the archives of aeolian pollution during the early 20th century.

  10. Exposure of school children to polycyclic aromatic hydrocarbons, heavy metals and radionuclides in the urban soil of Kragujevac city, Central Serbia.

    PubMed

    Stajic, J M; Milenkovic, B; Pucarevic, M; Stojic, N; Vasiljevic, I; Nikezic, D

    2016-03-01

    The concentrations of radionuclides, polycyclic aromatic hydrocarbons (PAHs) and heavy metals were measured in soil samples collected from school backyards and playgrounds in Kragujevac, one of the largest cities of Central Serbia. The activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs were determined using the HPGe semiconductor detector. The average values were 34.6, 44.7, 428.9 and 45.1 Bq kg(-1), respectively. The correlation between the activity concentrations of (226)Ra in the soil samples and the results of the previous measurement of (222)Rn concentrations in the indoor air was examined. The absorbed dose rates, the annual effective doses and excess lifetime cancer risk were also estimated. The activity concentrations of (226)Ra and (232)Th have shown normal distribution. The collected soil samples were analysed for PAHs by HPLC. All analysed soil samples contained PAHs, and their total amounts (for 15 measured compounds) were found to be between 0.038 and 3.136 mg kg(-1) of absolutely dry soil (a.d.s). In addition the concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were measured in the fourteen soil samples collected from the playgrounds of kindergartens. PMID:26706933

  11. Affects of wastewater discharge from mining on soil heavy metal pollution and enzyme activities in northern Hunan province, Central South China

    NASA Astrophysics Data System (ADS)

    Jiang, Ying; Hu, Xue-Feng; Shu, Ying; Yan, Xiao-Juan; Luo, Fan

    2013-04-01

    Hunan province, Central South China, is rich in mineral resources and also a well-known nonferrous metal base in China. Mining and ore processing there, however, are mostly conducted in indigenous methods, and thus causing heavy metal pollution of abundant farmland. Situated in northern Hunan province, Y county has antimony, manganese, vanadium, and pyrite mines, but still belongs to a region of rice cultivation, of which, paddy fields make up 84.5% of the total farmland. Our investigations found that irrigation water is threatened by the release of mining wastewater in the county. For example, a stream used for irrigation turns dark-red after long-term receiving wastewater discharged from a pyrite company at HS Town of the county. Concentrations of Cu, Zn, Cd, Fe and Mn in the stream water reach 0.03 mg kg-1, 2.14 mg kg-1, 0.02 mg kg-1, 96.0 mg kg-1 and 11.5 mg kg-1, respectively; these in the paddy soils nearby are 67.3 mg kg-1, 297 mg kg-1, 4.0 mg kg-1, 33.1 mg g-1 and 463 mg kg-1 on average, respectively, with a maximum of Cd reaching 16.8 mg kg-1. Microbial biomass and activities are significantly reduced by metal toxicity in the soils. The counts of fungal, actinomycin and bacterial colonies in the polluted soils are 8.8×103 /g (Fresh soil), 4.9×105 /g (Fresh soil) and 6.4×105 /g (Fresh soil), respectively, which are only 4.68%, 10.3% and 20.9% of these in non-polluted soils in Y county, respectively. Likewise, the microbial biomass (MB) - C and MB - N of the polluted soils are only 36.8% and 50.3% of these in the non-polluted, respectively. The activities of dehydrogenase, urease, catalase, acid and neutral phosphatase and sucrase in the polluted soils are only 41.2%, 49.8%, 56.8%, 69.9%, 80.7% and 81.0% of these in the non-polluted, respectively. There are significant negative correlations between Cu, Zn and Cd contents and the activities of dehydrogenase and catalase, suggesting that the two enzymes are the most sensitive to heavy metal toxicity in the

  12. Diffraction by random Ronchi gratings.

    PubMed

    Torcal-Milla, Francisco Jose; Sanchez-Brea, Luis Miguel

    2016-08-01

    In this work, we obtain analytical expressions for the near-and far-field diffraction of random Ronchi diffraction gratings where the slits of the grating are randomly displaced around their periodical positions. We theoretically show that the effect of randomness in the position of the slits of the grating produces a decrease of the contrast and even disappearance of the self-images for high randomness level at the near field. On the other hand, it cancels high-order harmonics in far field, resulting in only a few central diffraction orders. Numerical simulations by means of the Rayleigh-Sommerfeld diffraction formula are performed in order to corroborate the analytical results. These results are of interest for industrial and technological applications where manufacture errors need to be considered. PMID:27505363

  13. Breakdown of QCD factorization in hard diffraction

    NASA Astrophysics Data System (ADS)

    Kopeliovich, B. Z.

    2016-07-01

    Factorization of short- and long-distance interactions is severely broken in hard diffractive hadronic collisions. Interaction with the spectator partons leads to an interplay between soft and hard scales, which results in a leading twist behavior of the cross section, on the contrary to the higher twist predicted by factorization. This feature is explicitly demonstrated for diffractive radiation of abelian (Drell-Yan, gauge bosons, Higgs) and non-abelian (heavy flavors) particles.

  14. Silt fraction heavy-mineral distributions in a lateritic environment: the rivers and insular shelf of north-central Puerto Rico

    USGS Publications Warehouse

    Poppe, L.J.; Commeau, J.A.; Luepke, G.

    1995-01-01

    This fraction, which is enriched in heavy minerals relative to the sand fraction, is mainly detrital but contains a strong authigenic component. The authigenic silt heavy-mineral fraction is largely a product of the lateritic weathering and dominated by iron oxides and alterites. Grains of bladed rutile and leached ilmenite are common. Spatial variability in silt-fraction mineralogy is considerable. Within the Rio Cibuco system variability is related to compositional differences in rapidly eroding source rocks. On the shelf, silt heavy-mineral abundances are greatest at the river mouths and decrease seaward. Variability in the shelf samples is controlled primarily by source rivers and shelf sorting processes. -from Authors

  15. Detonation diffraction through different geometries

    NASA Astrophysics Data System (ADS)

    Sorin, Rémy; Zitoun, Ratiba; Khasainov, Boris; Desbordes, Daniel

    2009-04-01

    We performed the study of the diffraction of a self-sustained detonation from a cylindrical tube (of inner diameter d) through different geometric configurations in order to characterise the transmission processes and to quantify the transmission criteria to the reception chamber. For the diffraction from a tube to the open space the transmission criteria is expressed by d c = k c · λ (with λ the detonation cell size and k c depending on the mixture and on the operture configuration, classically 13 for alkane mixtures with oxygen). The studied geometries are: (a) a sharp increase of diameter ( D/ d > 1) with and without a central obstacle in the diffracting section, (b) a conical divergent with a central obstacle in the diffracting section and (c) an inversed intermediate one end closed tube insuring a double reflection before a final diffraction between the initiator tube and the reception chamber. The results for case A show that the reinitiation process depends on the ratio d/ λ. For ratios below k c the re-ignition takes place at the receptor tube wall and at a fixed distance from the step, i.e. closely after the diffracted shock reflection shows a Mach stem configuration. For ratios below a limit ratio k lim (which depends on D/ d) the re-ignition distance increases with the decrease of d/λ. For both case A and B the introduction of a central obstacle (of blockage ratio BR = 0.5) at the exit of the initiator tube decreases the critical transmission ratio k c by 50%. The results in configuration C show that the re-ignition process depends both on d/ λ and the geometric conditions. Optimal configuration is found that provides the transmission through the two successive reflections (from d = 26 mm to D ch = 200 mm) at as small d/ λ as 2.2 whatever the intermediate diameter D is. This configuration provides a significant improvement in the detonation transmission conditions.

  16. Synoptic climatological study on the decrease in heavy snowfall days in Hokuriku District of Central Japan after the latter half of 1980s

    NASA Astrophysics Data System (ADS)

    Kato, Kuranoshin; Kan, Yuusuke

    2010-05-01

    Many reports point out that the total snowfall amount in winter in the Japan Sea side of the Japan Islands, such as Hokuriku District, decreased considerably after the latter half of 1980s, in coincidence with the Global Warming together with the interdecadal variation. As for around December, this seems to be partly because more precipitation in the winter monsoon situation is brought as rainfall (not as snowfall), due to the warmer temperature than before. On the other hand, contribution of the daily heavy snowfall events there would be also important for mid-winter when the air temperature is the lowest in a year. Thus the present study examined the contribution of the heavy snowfall events to the difference of the total snowfall amount before and after the middle of 1980s, based on the daily data at several operational surface observation stations of JMA in the Hokuriku District for 1971 - 2001. Then the related daily atmospheric fields were analyzed climatologically with use of the NCEP/NCAR re-analysis data with every 2.5 degrees latitude/longitude interval. In the former half of the analysis period, the larger total snowfall amount in January in the Hokuriku District, such as at Takada, was greatly contributed to by the heavy snowfall events with more than 30 cm/day (referred to as "heavy snowfall day", hereafter). The decrease in the total amount in the latter half of that period was due to that in the contribution of "heavy snowfall days". Furthermore, the "heavy snowfall days" tended to appear in the persistent snowfall episodes (including also the days with 10 cm/day), before around 1986. In short, the decrease in the total snowfall in the latter half period there seems to be reflected by the weakening of persistency of heavy snowfall episodes. As shown by Akiyama (1981a and b) in detail, there are several different synoptic situations in the winter monsoon situation for bringing heavy snowfall there (the "mountain snow type" and the "plateau snow type

  17. Unusual features of Drell-Yan diffraction

    SciTech Connect

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan; Tarasov, A. V.

    2006-12-01

    The cross section of the diffractive Drell-Yan (DY) process, pp{yields}llXp, where the system llX is separated by a large rapidity gap from the recoil proton, is calculated in the light-cone dipole approach. This process reveals unusual features, quite different from what is known for diffractive deeply inelastic scattering (DIS) and non-Abelian radiation: (i) the diffractive radiation of a heavy dilepton by a quark vanishes in the forward direction; (ii) the diffractive production of a dilepton is controlled by the large hadronic radius; (iii) in contrast with DIS where diffraction is predominantly soft, the diffractive DY reaction is semihard-semisoft; (iv) as a result of the saturated shape of the dipole cross section, the fraction of diffractive DY events steeply falls with energy but rises as a function of the hard scale. These features are common for other Abelian bremsstrahlung processes (higgsstrahlung, Z-strahlung, etc.). Measurements of diffractive DY processes at modern colliders would be a sensitive probe for the shape of the dipole cross section at large separations.

  18. Heavy metals and TPH effects on microbial abundance and diversity in two estuarine areas of the southern-central coast of São Paulo State, Brazil.

    PubMed

    Pinto, Aline Bartelochi; Pagnocca, Fernando Carlos; Pinheiro, Marcelo Antonio Amaro; Fontes, Roberto Fioravanti Carelli; de Oliveira, Ana Júlia Fernandes Cardoso

    2015-07-15

    Coastal areas may be impacted by human and industrial activities, including contamination by wastewater, heavy metals and hydrocarbons. This study aimed to evaluate the impact of hydrocarbons (TPH) and metals on the microbiota composition and abundance in two estuarine systems in the coast of São Paulo: the Santos (SE) and Itanhaém (IE) estuaries. The SE was found to be chronically contaminated by heavy metals and highly contaminated by hydrocarbons. This finding was correlated with the increased density of cyanobacteria in sediments and suggests the possible use of cyanobacteria for bioremediation. These contaminants influence the density and composition of estuarine microbiota that respond to stress caused by human activity. The results are troubling because quantitative and qualitative changes in the microbiota of estuarine sediments may alter microbiological processes such as decomposition of organic matter. Moreover, this pollution can result in damage to the environment, biota and human health. PMID:26021289

  19. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  20. Centrality dependence of the parton bubble model for high-energy heavy-ion collisions and fireball surface substructure at energies available at the BNL relativistic heavy ion collider (RHIC)

    NASA Astrophysics Data System (ADS)

    Lindenbaum, S. J.; Longacre, R. S.

    2008-11-01

    In an earlier paper we developed a QCD-inspired theoretical parton bubble model (PBM) for RHIC/LHC. The motivation for the PBM was to develop a model that would reasonably quantitatively agree with the strong charged particle pair correlations observed by the STAR Collaboration at RHIC in Au+Au central collisions at sNN=200 GeV in the transverse momentum range 0.8 to 2.0 GeV/c. The model was constructed to also agree with the Hanbury Brown and Twiss (HBT) observed small final-state source size ~2 fm radii in the transverse momentum range above 0.8 GeV/c. The model assumed a substructure of a ring of localized adjoining ~2 fm radius bubbles perpendicular to the collider beam direction, centered on the beam, at midrapidity. The bubble ring was assumed to be located on the expanding fireball surface of the Au+Au collision. These bubbles consist almost entirely of gluons and form gluonic hot spots on the fireball surface. We achieved a reasonable quantitative agreement with the results of both the physically significant charge-independent (CI) and charge-dependent (CD) correlations that were observed. In this paper we extend the model to include the changing development of bubbles with centrality from the most central region where bubbles are very important to the most peripheral where the bubbles are gone. Energy density is found to be related to bubble formation and as centrality decreases the maximum energy density and bubbles shift from symmetry around the beam axis to the reaction plane region, causing a strong correlation of bubble formation with elliptic flow. We find reasonably quantitative agreement (within a few percent of the total correlations) with a new precision RHIC experiment that extended the centrality region investigated to the range 0% 80% (most central to most peripheral). The characteristics and behavior of the bubbles imply they represent a significant substructure formed on the surface of the fireball at kinetic freezeout.

  1. Local to regional scale industrial heavy metal pollution recorded in sediments of large freshwater lakes in central Europe (lakes Geneva and Lucerne) over the last centuries.

    PubMed

    Thevenon, Florian; Graham, Neil D; Chiaradia, Massimo; Arpagaus, Philippe; Wildi, Walter; Poté, John

    2011-12-15

    This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750-1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (>100 μg Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents. PMID:22047737

  2. Harmonic diffractive lenses

    SciTech Connect

    Sweeney, D.W.; Sommargren, G.E.

    1995-05-10

    The harmonic diffractive lens is a diffractive imaging lens for which the optical path-length transition between adjacent facets is an integer multiple {ital m} of the design wavelength {lambda}{sub 0}. The total lens thickness in air is {ital m}{lambda}{sub 0}/({ital n} {minus} 1), which is {ital m} times thicker than the so-called modulo 2{pi} diffractive lens. Lenses constructed in this way have hybrid properties of both refractive and diffractive lenses. Such a lens will have a diffraction-limited, common focus for a number of discrete wavelengths across the visible spectrum. A 34.75-diopter, 6-mm-diameter lens is diamond turned in aluminum and replicated in optical materials. The sag of the lens is 23 {mu}m. Modulation transfer function measurements in both monochromatic and white light verify the performance of the lens. The lens approaches the diffraction limit for 10 discrete wavelengths across the visible spectrum.

  3. A Study of a Heavy Rainfall Event in the Central Part of Korea in a Situation of a Synoptic Scale Ridge over the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Kim, Ah-hyun; Lee, Yunkyu

    2016-04-01

    Observational and numerical studies have been carried out to explain the heavy rainfall event over Seoul metropolitan area and Gyeonggi province on June 29 2011. The characteristic features for this heavy rainfall event is convergence produced by the association of low-level mesoscale trough above the Yellow sea in a situation of a synoptic scale ridge over the Korean peninsula. Maximum of 234mm rainfall was recorded in one day, and most of the rainfall occurred in 12 hours. The major cause of this event is the formation of convergence zone. Abrupt wind direction change created by south-westerly low-level jet at the windward side and northerly or south-easterly wind caused by synoptic scale ridge at the lee side of the rainfall region produce horizontal wind shear in the middle of the mesoscale pressure trough. Also, wind speed difference at the exit of the low-level jet is another cause of the convergence. The low-level jet forms around the East China Sea. Land-sea heat capacity difference causes the increase of meridional temperature gradient around the coast line of the East China Sea during the daytime and induces the meridional pressure gradient increase. Therefore, low-level jet strengthens at the area where the meridional pressure gradient is strong. This low-level jet moves along the western flank of Western Pacific Subtropical High (WPSH) and impacts on Korean Peninsula. Formation of the synoptic scale ridge seems to be associated with WPSH and the strong low pressure system at the northeast of Korean Peninsula. The strong cyclone suppresses the northern flank of the WPSH, and relatively high pressure forms at the windward and lee side of the pressure low. Orographic effect plays an important role in intensifying pressure ridge over the Korean Peninsula. Numerical studies have been carried out to understand the effect of the condensation latent heat, land-sea heat capacity difference, and the orography by using WRF model. Topography sensitivity simulation

  4. Diffraction by cold atoms

    NASA Astrophysics Data System (ADS)

    Strauch, F.; Gomer, V.; Schadwinkel, H.; Ueberholz, B.; Haubrich, D.; Meschede, D.

    1998-01-01

    We have observed diffraction of a laser probe beam by a trapped sample of cold atoms. The effect is only visible in the vicinity of a resonance line. The observed diffraction pattern arises from interference of the incident and scattered light wave, allowing reconstruction of geometric properties of the trapped sample from the holographic record.

  5. Diffraction Results from CDF

    SciTech Connect

    Goulianos, Konstantin

    2012-04-01

    We present final results by the CDF II collaboration on diffractive W and Z production, report on the status of ongoing analyses on diffractive dijet production and on rapidity gaps between jets, and briefly summarize results obtained on exclusive production pointing to their relevance to calibrating theoretical models used to predict exclusive Higgs-boson production at the LHC.

  6. Phononic crystal diffraction gratings

    NASA Astrophysics Data System (ADS)

    Moiseyenko, Rayisa P.; Herbison, Sarah; Declercq, Nico F.; Laude, Vincent

    2012-02-01

    When a phononic crystal is interrogated by an external source of acoustic waves, there is necessarily a phenomenon of diffraction occurring on the external enclosing surfaces. Indeed, these external surfaces are periodic and the resulting acoustic diffraction grating has a periodicity that depends on the orientation of the phononic crystal. This work presents a combined experimental and theoretical study on the diffraction of bulk ultrasonic waves on the external surfaces of a 2D phononic crystal that consists of a triangular lattice of steel rods in a water matrix. The results of transmission experiments are compared with theoretical band structures obtained with the finite-element method. Angular spectrograms (showing frequency as a function of angle) determined from diffraction experiments are then compared with finite-element simulations of diffraction occurring on the surfaces of the crystal. The experimental results show that the diffraction that occurs on its external surfaces is highly frequency-dependent and has a definite relation with the Bloch modes of the phononic crystal. In particular, a strong influence of the presence of bandgaps and deaf bands on the diffraction efficiency is found. This observation opens perspectives for the design of efficient phononic crystal diffraction gratings.

  7. Heavy flavors

    SciTech Connect

    Cox, B.; Gilman, F.J.; Gottschalk, T.D.

    1986-11-01

    A range of issues pertaining to heavy flavors at the SSC is examined including heavy flavor production by gluon-gluon fusion and by shower evolution of gluon jets, flavor tagging, reconstruction of Higgs and W bosons, and the study of rare decays and CP violation in the B meson system. A specific detector for doing heavy flavor physics and tuned to this latter study at the SSC, the TASTER, is described. 36 refs., 10 figs.

  8. Diffraction at the Tevatron and the LHC

    NASA Astrophysics Data System (ADS)

    Royon, C.

    2008-09-01

    In this paper, we present and discuss the most recent results on inclusive diffraction at the Tevatron collider and give the prospects at the LHC. We also describe the search for exclusive events at the Tevatron. Of special interest is the exclusive production of Higgs boson and heavy objects (W, top, stop pairs) at the LHC which will require precise measurements and analyses of inclusive and exclusive diffraction to constrain further the gluon density in the pomeron. At the end of the paper, we describe the projects to install forward detectors at the LHC to fulfil these measurements. We also describe the diffractive experiments accepted or in project at the LHC: TOTEM, ALFA in ATLAS, and the AFP/FP420 projects.

  9. Diffractive properties of imaginary-part photonic crystal slab

    PubMed Central

    2012-01-01

    The diffraction spectra of imaginary-part photonic crystal (IPPC) slabs are analyzed using the scattering-matrix method. By investigating the thickness dependence of the diffraction, we find a remarkable red shift of central wavelength of the diffraction spectrum, which obviously distinguishes from the phenomenon of spectral hole. We observe that diffraction efficiency can be enhanced more than 20-fold by optimizing the geometry parameters. These imply that the diffraction spectra of the IPPC slab can be controlled at will and used to guide the design to achieve useful nanoscale devices. PMID:22720871

  10. Promotion of renewable energy to mitigate impact of heavy use of carbon energy on society and climate change in Central Sub-Saharan Africa remote areas.

    NASA Astrophysics Data System (ADS)

    Kenfack, Joseph; Bignom, Blaise

    2015-04-01

    Sub-Saharan Africa owns important renewable energy potential and is still heavily using carbon energy. This is having a negative impact on the climate and on the environment. Given the local cost of carbon energy, the purchase power of people, the availability and the reserve of carbon energy in the area, this resource is being heavily used. This practice is harmful to the climate and is also resulting on poor effort to promote renewable energy in remote areas. The important renewable energy potential is still suffering from poor development. The purpose of this paper is among other things aiming at showing the rate of carbon energy use and its potential impact on climate and environment. We will also ensure that the renewable energy resources of Central Sub-Saharan Africa are known and are subject to be used optimally to help mitigate climate change. After showing some negative impacts of carbon energy used in the area, the work also suggests actions to promote and sustain the development of renewable energy. Based on the knowledge of the Central African energy sector, this paper will identify actions for reduce access to carbon energy and improved access to sustainable, friendly, affordable energy services to users as well as a significant improvement of energy infrastructure and the promotion of energy efficiency. We will show all type of carbon energy used, the potential for solar, biomass and hydro while showing where available the level of development. After a swot analysis of the situation, identified obstacles for the promotion of clean energy will be targeted. Finally, suggestions will be made to help the region develop a vision aiming at developing good clean energy policy to increase the status of renewable energy and better contribute to fight against climate change. Cameroon case study will be examined as illustration. Analysis will be made from data collected in the field. |End Text|

  11. Calculating incoherent diffraction MTF

    NASA Astrophysics Data System (ADS)

    Friedman, Melvin; Vizgaitis, Jay

    2008-04-01

    The incoherent diffraction MTF plays an increasingly important role in the range performance of imaging systems as the wavelength increases and the optical aperture decreases. Accordingly, all NVESD imager models have equations that describe the incoherent diffraction MTF of a circular entrance pupil. NVThermIP, a program which models thermal imager range performance, has built in equations which analytically model the incoherent diffraction MTF of a circular entrance pupil and has a capability to input a table that describes the MTF of other apertures. These can be calculated using CODE V, which can numerically calculate the incoherent diffraction MTF in the vertical or horizontal direction for an arbitrary aperture. However, we are not aware of any program that takes as input a description of the entrance pupil and analytically outputs equations that describe the incoherent diffraction MTF. This work explores the effectiveness of Mathematica to analytically and numerically calculate the incoherent diffraction MTF for an arbitrary aperture. In this work, Mathematica is used to analytically and numerically calculate the incoherent diffraction MTF for a variety of apertures and the results are compared with CODE V calculations.

  12. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, Michael D.; Britten, Jerald A.; Nguyen, Hoang T.; Boyd, Robert; Shore, Bruce W.

    1999-01-01

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.

  13. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, M.D.; Britten, J.A.; Nguyen, H.T.; Boyd, R.; Shore, B.W.

    1999-05-25

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described. 7 figs.

  14. Diffraction of light by an opaque sphere. 1: Description and properties of the diffraction pattern

    SciTech Connect

    Sommargren, G.E. ); Weaver, H.J. )

    1990-11-01

    In this paper we discuss the diffraction pattern resulting from the propagation of light past an opaque obstacle with a circular cross section. A mathematical description of the diffraction pattern is obtained in the Fresnel region using scalar diffraction theory and is presented in terms of the Lommel functions. This description is shown experimentally to be quite accurate, not only for near axis points within the shadow region but also well past the shadow's edge into the directly illuminated region. The mathematical description is derived for spherical wave illumination and an isomorphic relation is developed relating it to plane wave illumination. The size of the central bright spot (as well as the subsequent diffraction rings), the axial intensity, and the intensity along the geometric shadow are characterized in terms of point source location and the distance of propagation past the circular obstacle. Key words: Spherical diffraction, isomorphic propagation theory, Lommel functions.

  15. Hard diffraction at CDF

    SciTech Connect

    Melese, P.L.; CDF Collaboration

    1996-07-01

    We present new evidence for events with a rapidity gap between jets in {bar p}-p collisions at {radical}s = 1.8 TeV based on data collected by triggering the Collider Detector at Fermilab on two high transverse momentum forward jets and results of a search for diffractive W{+-} and dijet production where diffraction is tagged by the rapidity gap technique. We also present the results of a search for diffractive dijets using data collected by triggering on a very forward particle in the recently installed roman-pot detectors. The dijet events exhibit additional diffractive characteristics such as rapidity gaps and boosted center of mass system, however the recoil antiproton measured in the roman-pots is in a regime in which the non- pomeron contribution is significant.

  16. Reflective diffraction grating

    DOEpatents

    Lamartine, Bruce C.

    2003-06-24

    Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.

  17. Powder Diffraction: By Decades

    NASA Astrophysics Data System (ADS)

    David, William I. F.

    This introductory chapter reviews the first 100 years of powder diffraction, decade by decade, from the earliest X-ray powder diffraction measurements of the crystal structure of graphite through to the diversity and complexity of twenty-first century powder diffraction. Carbon features as an illustrative example throughout the discussion of these ten decades from graphite and the disorder of carbon black through to lonsdaleite, the elusive hexagonal polymorph of diamond, and C60, the most symmetrical of molecules. Electronics and computing have played a leading role in the development of powder diffraction, particularly over the past 60 years, and the Moore's Law decade-by-decade rise in computing power is clear in the increasing complexity of powder diffraction experiments and material systems that can be studied. The chapter concludes with a final discussion of decades - the four decades of length-scale from the ångstrom to the micron that not only represent the domain of powder diffraction but are also the distances that will dominate twenty-first century science and technology.

  18. Multipath analysis diffraction calculations

    NASA Technical Reports Server (NTRS)

    Statham, Richard B.

    1996-01-01

    This report describes extensions of the Kirchhoff diffraction equation to higher edge terms and discusses their suitability to model diffraction multipath effects of a small satellite structure. When receiving signals, at a satellite, from the Global Positioning System (GPS), reflected signals from the satellite structure result in multipath errors in the determination of the satellite position. Multipath error can be caused by diffraction of the reflected signals and a method of calculating this diffraction is required when using a facet model of the satellite. Several aspects of the Kirchhoff equation are discussed and numerical examples, in the near and far fields, are shown. The vector form of the extended Kirchhoff equation, by adding the Larmor-Tedone and Kottler edge terms, is given as a mathematical model in an appendix. The Kirchhoff equation was investigated as being easily implemented and of good accuracy in the basic form, especially in phase determination. The basic Kirchhoff can be extended for higher accuracy if desired. A brief discussion of the method of moments and the geometric theory of diffraction is included, but seems to offer no clear advantage in implementation over the Kirchhoff for facet models.

  19. Diffraction radiation generators

    NASA Astrophysics Data System (ADS)

    Shestopalov, Viktor P.; Vertii, Aleksei A.; Ermak, Gennadii P.; Skrynnik, Boris K.; Khlopov, Grigorii I.; Tsvyk, Aleksei I.

    Research in the field of diffraction radiation generators (DRG) conducted at the Radio Physics and electronics Institute of the Ukranian Academy of Sciences over the past 25 years is reviewed. The effect of diffraction radiation is analyzed in detail, and various operating regimes of DRGs are discussed. The discussion then focuses on the principal requirements for the design of packaged DRGs and their principal parameters. Finally, applications of DRGs in various fields of science and technology are reviewed, including such applications as DRG spectroscopy, diagnostics of plasma, biological specimens, and vibration, and DRG radar systems.

  20. Diffraction on nuclei: Effects of nucleon correlations

    SciTech Connect

    Alvioli, M.; Atti, C. Ciofi degli; Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2010-02-15

    The cross sections for a variety of diffractive processes in proton-nucleus scattering, associated with large gaps in rapidity, are calculated within an improved Glauber-Gribov theory, where the inelastic shadowing corrections are summed to all orders by employing the dipole representation. The effects of nucleon correlations, leading to a modification of the nuclear thickness function, are also taken into account. Numerical calculations are performed for the energies of the Hadron-Electron Ring Accelerator-B experiment, the Relativistic Heavy Ion Collider and Large Hadron Collider, and for several nuclei. It is found that whereas the Gribov corrections generally make nuclear matter more transparent, nucleon correlations act in the opposite direction and have important effects in various diffractive processes.

  1. DIFFRACTION FROM MODEL CRYSTALS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although calculating X-ray diffraction patterns from atomic coordinates of a crystal structure is a widely available capability, calculation from non-periodic arrays of atoms has not been widely applied to cellulose. Non-periodic arrays result from modeling studies that, even though started with at...

  2. Calculating cellulose diffraction patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  3. Diffraction of light by an opaque sphere. 1: Description and properties of the diffraction pattern.

    PubMed

    Sommargren, G E; Weaver, H J

    1990-11-01

    In this paper we discuss the diffraction pattern resulting from the propagation of light past an opaque obstacle with a circular cross section. A mathematical description of the diffraction pattern is obtained in the Fresnel region using scalar diffraction theory and is presented in terms of the Lommel functions. This description is shown experimentally to be quite accurate, not only for near axis points within the shadow region but also well past the shadow's edge into the directly illuminated region. The mathematical description is derived for spherical wave illumination and an isomorphic relation is developed relating it to plane wave illumination. The size of the central bright spot (as well as the subsequent diffraction rings), the axial intensity, and the intensity along the geometric shadow are characterized in terms of point source location and the distance of propagation past the circular obstacle. PMID:20577447

  4. A Heavy Flavor Tracker for STAR

    SciTech Connect

    Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Miller,M.; Surrow, B.; Van Nieuwenhuizen G.; Bieser, F.; Gareus, R.; Greiner,L.; Lesser, F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

    2005-03-14

    We propose to construct a Heavy Flavor Tracker (HFT) for theSTAR experiment at RHIC. The HFT will bring new physics capabilities toSTAR and it will significantly enhance the physics capabilities of theSTAR detector at central rapidities. The HFT will ensure that STAR willbe able to take heavy flavor data at all luminosities attainablethroughout the proposed RHIC II era.

  5. A Heavy Flavor Tracker for STAR

    SciTech Connect

    Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Surrow,B.; Van Nieuwenhuizen, G.; Bieser, F.; Gareus, R.; Greiner, L.; Lesser,F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

    2005-03-14

    We propose to construct a Heavy Flavor Tracker (HFT) for the STAR experiment at RHIC. The HFT will bring new physics capabilities to STAR and it will significantly enhance the physics capabilities of the STAR detector at central rapidities. The HFT will ensure that STAR will be able to take heavy flavor data at all luminosities attainable throughout the proposed RHIC II era.

  6. QCD and hard diffraction at the LHC

    SciTech Connect

    Albrow, Michael G.; /Fermilab

    2005-09-01

    As an introduction to QCD at the LHC the author gives an overview of QCD at the Tevatron, emphasizing the high Q{sup 2} frontier which will be taken over by the LHC. After describing briefly the LHC detectors the author discusses high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. The author introduces the FP420 project to measure the scattered protons 420m downstream of ATLAS and CMS.

  7. Colored Diffraction Catastrophes

    NASA Astrophysics Data System (ADS)

    Berry, M. V.; Klein, S.

    1996-03-01

    On fine scales, caustics produced with white light show vividly colored diffraction fringes. For caustics described by the elementary catastrophes of singularity theory, the colors are characteristic of the type of singularity. We study the diffraction colors of the fold and cusp catastrophes. The colors can be simulated computationally as the superposition of monochromatic patterns for different wavelengths. Far from the caustic, where the luminosity contrast is negligible, the fringe colors persist; an asymptotic theory explains why. Experiments with caustics produced by refraction through irregular bathroom-window glass show good agreement with theory. Colored fringes near the cusp reveal fine lines that are not present in any of the monochromatic components; these lines are explained in terms of partial decoherence between rays with widely differing path differences.

  8. Colored diffraction catastrophes.

    PubMed Central

    Berry, M V; Klein, S

    1996-01-01

    On fine scales, caustics produced with white light show vividly colored diffraction fringes. For caustics described by the elementary catastrophes of singularity theory, the colors are characteristic of the type of singularity. We study the diffraction colors of the fold and cusp catastrophes. The colors can be simulated computationally as the superposition of monochromatic patterns for different wavelengths. Far from the caustic, where the luminosity contrast is negligible, the fringe colors persist; an asymptotic theory explains why. Experiments with caustics produced by refraction through irregular bathroom-window glass show good agreement with theory. Colored fringes near the cusp reveal fine lines that are not present in any of the monochromatic components; these lines are explained in terms of partial decoherence between rays with widely differing path differences. Images Fig. 1 Fig. 2 Fig. 3 Fig. 6 Fig. 8 Fig. 9 Fig. 10 PMID:11607642

  9. Diffraction before destruction

    PubMed Central

    Chapman, Henry N.; Caleman, Carl; Timneanu, Nicusor

    2014-01-01

    X-ray free-electron lasers have opened up the possibility of structure determination of protein crystals at room temperature, free of radiation damage. The femtosecond-duration pulses of these sources enable diffraction signals to be collected from samples at doses of 1000 MGy or higher. The sample is vaporized by the intense pulse, but not before the scattering that gives rise to the diffraction pattern takes place. Consequently, only a single flash diffraction pattern can be recorded from a crystal, giving rise to the method of serial crystallography where tens of thousands of patterns are collected from individual crystals that flow across the beam and the patterns are indexed and aggregated into a set of structure factors. The high-dose tolerance and the many-crystal averaging approach allow data to be collected from much smaller crystals than have been examined at synchrotron radiation facilities, even from radiation-sensitive samples. Here, we review the interaction of intense femtosecond X-ray pulses with materials and discuss the implications for structure determination. We identify various dose regimes and conclude that the strongest achievable signals for a given sample are attained at the highest possible dose rates, from highest possible pulse intensities. PMID:24914146

  10. Polychromatic diffraction contrast tomography

    SciTech Connect

    King, A.; Reischig, P.; Adrien, J.; Peetermans, S.; Ludwig, W.

    2014-11-15

    This tutorial review introduces the use of polychromatic radiation for 3D grain mapping using X-ray diffraction contrast tomography. The objective is to produce a 3D map of the grain shapes and orientations within a bulk, millimeter-sized polycrystalline sample. The use of polychromatic radiation enables the standard synchrotron X-ray technique to be applied in a wider range of contexts: 1) Using laboratory X-ray sources allows a much wider application of the diffraction contrast tomography technique. 2) Neutron sources allow large samples, or samples containing high Z elements to be studied. 3) Applied to synchrotron sources, smaller samples may be treated, or faster measurements may be possible. Challenges and particularities in the data acquisition and processing, and the limitations of the different variants, are discussed. - Highlights: • We present a tutorial review of polychromatic diffraction contrast tomography techniques. • The use of polychromatic radiation allows the standard synchrotron DCT technique to be extended to a range of other sources. • The characteristics and limitations of all variants of the techniques are derived, discussed and compared. • Examples using laboratory X-ray and cold neutron radiation are presented. • Suggestions for the future development of these techniques are presented.

  11. DPEMC: A Monte Carlo for double diffraction

    NASA Astrophysics Data System (ADS)

    Boonekamp, M.; Kúcs, T.

    2005-05-01

    We extend the POMWIG Monte Carlo generator developed by B. Cox and J. Forshaw, to include new models of central production through inclusive and exclusive double Pomeron exchange in proton-proton collisions. Double photon exchange processes are described as well, both in proton-proton and heavy-ion collisions. In all contexts, various models have been implemented, allowing for comparisons and uncertainty evaluation and enabling detailed experimental simulations. Program summaryTitle of the program:DPEMC, version 2.4 Catalogue identifier: ADVF Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVF Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer: any computer with the FORTRAN 77 compiler under the UNIX or Linux operating systems Operating system: UNIX; Linux Programming language used: FORTRAN 77 High speed storage required:<25 MB No. of lines in distributed program, including test data, etc.: 71 399 No. of bytes in distributed program, including test data, etc.: 639 950 Distribution format: tar.gz Nature of the physical problem: Proton diffraction at hadron colliders can manifest itself in many forms, and a variety of models exist that attempt to describe it [A. Bialas, P.V. Landshoff, Phys. Lett. B 256 (1991) 540; A. Bialas, W. Szeremeta, Phys. Lett. B 296 (1992) 191; A. Bialas, R.A. Janik, Z. Phys. C 62 (1994) 487; M. Boonekamp, R. Peschanski, C. Royon, Phys. Rev. Lett. 87 (2001) 251806; Nucl. Phys. B 669 (2003) 277; R. Enberg, G. Ingelman, A. Kissavos, N. Timneanu, Phys. Rev. Lett. 89 (2002) 081801; R. Enberg, G. Ingelman, L. Motyka, Phys. Lett. B 524 (2002) 273; R. Enberg, G. Ingelman, N. Timneanu, Phys. Rev. D 67 (2003) 011301; B. Cox, J. Forshaw, Comput. Phys. Comm. 144 (2002) 104; B. Cox, J. Forshaw, B. Heinemann, Phys. Lett. B 540 (2002) 26; V. Khoze, A. Martin, M. Ryskin, Phys. Lett. B 401 (1997) 330; Eur. Phys. J. C 14 (2000) 525; Eur. Phys. J. C 19 (2001) 477; Erratum, Eur. Phys. J. C 20 (2001) 599; Eur

  12. Diffraction of a Laser Beam.

    ERIC Educational Resources Information Center

    Jodoin, Ronald E.

    1979-01-01

    Investigates the effect of the nonuniform irradiance across a laser beam on diffraction of the beam, specifically the Fraunhofer diffraction of a laser beam with a Gaussian irradiance profile as it passes through a circular aperture. (GA)

  13. Aberrations of diffracted wave fields. II. Diffraction gratings.

    PubMed

    Mahajan, V N

    2000-12-01

    The Rayleigh-Sommerfeld theory is applied to diffraction of a spherical wave by a grating. The grating equation is obtained from the aberration-free diffraction pattern, and its aberrations are shown to be the same as the conventional aberrations obtained by using Fermat's principle. These aberrations are shown to be not associated with the diffraction process. Moreover, it is shown that the irradiance distribution of a certain diffraction order is the Fraunhofer diffraction pattern of the grating aperture as a whole aberrated by the aberration of that order. PMID:11140481

  14. Recent diffractive results from HERA

    NASA Astrophysics Data System (ADS)

    Valkárová, Alice

    2016-07-01

    The diffractive dijet cross sections for photoproduction and deep inelastic scattering were studied and compared with theoretical NLO QCD predictions. The results of exclusive dijet production were compared to predictions from models which are based on different assumptions about the nature of diffractive exchange. Isolated prompt photons in diffractive photoproduction produced inclusively or together with a jet were studied for the first time.

  15. Spectral diffraction efficiency characterization of broadband diffractive optical elements.

    SciTech Connect

    Choi, Junoh; Cruz-Cabrera, Alvaro Augusto; Tanbakuchi, Anthony

    2013-03-01

    Diffractive optical elements, with their thin profile and unique dispersion properties, have been studied and utilized in a number of optical systems, often yielding smaller and lighter systems. Despite the interest in and study of diffractive elements, the application has been limited to narrow spectral bands. This is due to the etch depths, which are optimized for optical path differences of only a single wavelength, consequently leading to rapid decline in efficiency as the working wavelength shifts away from the design wavelength. Various broadband diffractive design methodologies have recently been developed that improve spectral diffraction efficiency and expand the working bandwidth of diffractive elements. We have developed diffraction efficiency models and utilized the models to design, fabricate, and test two such extended bandwidth diffractive designs.

  16. Heavy particle production at the SSC

    SciTech Connect

    Brodsky, S.J.; Haber, H.E.; Gunion, J.F.

    1984-03-01

    Predictions for the production of heavy quarks, supersymmetric particles, and other colored systems at high energy due to intrinsic twist-six components in the proton wavefunction are given. We also suggest the possibility of using asymmetric collision energies (e.g., via intersecting rings at the SSC) in order to facilitate the study of forward and diffractive particle production processes. 9 references.

  17. Relativistic heavy ion facilities: worldwide

    SciTech Connect

    Schroeder, L.S.

    1986-05-01

    A review of relativistic heavy ion facilities which exist, are in a construction phase, or are on the drawing boards as proposals is presented. These facilities span the energy range from fixed target machines in the 1 to 2 GeV/nucleon regime, up to heavy ion colliders of 100 GeV/nucleon on 100 GeV/nucleon. In addition to specifying the general features of such machines, an outline of the central physics themes to be carried out at these facilities is given, along with a sampling of the detectors which will be used to extract the physics. 22 refs., 17 figs., 3 tabs.

  18. Hard diffraction in Pythia 8

    NASA Astrophysics Data System (ADS)

    Overgaard Rasmussen, Christine

    2016-07-01

    We present an overview of the options for diffraction implemented in the general-purpose event generator Pythia 8 [1]. We review the existing model for soft diffraction and present a new model for hard diffraction. Both models use the Pomeron approach pioneered by Ingelman and Schlein, factorising the diffractive cross section into a Pomeron flux and a Pomeron PDF, with several choices for both implemented in Pythia 8. The model of hard diffraction is implemented as a part of the multiparton interactions (MPI) framework, thus introducing a dynamical gap survival probability that explicitly breaks factorisation.

  19. Heavy loads

    SciTech Connect

    Metz, D.

    1982-01-01

    The extreme pressures on the roof and walls of an earth-sheltered residential home are discussed and the need for careful planning is stressed. Pertinent terms are defined. Footings and wall structure (reinforced concrete walls and concrete block walls) are described. Roofing systems are discussed in detail and illustrated: (1) poured-in-place concrete roof slabs; (2) pre-cast concrete planks; and (3) heavy timber roofs. Insulation of earth-sheltered homes is reviewed in terms of using: (1) urethanes; (2) extruded polystyrene; and (3) expanded polystyrene. Advantages, disadvantages, R-factors, costs, and installation are discussed. (MJJ)

  20. Structured beam diffraction.

    PubMed

    Castagna, R; Di Donato, A; Nucara, L; Xu, J H; Lucchetta, D E; Simoni, F

    2016-04-01

    We report on the observation of a modulated pattern induced by a single laser beam in a polymeric film. In spite of the simple geometrical configuration, the analysis of the far field diffraction pattern allows a sensitive retrieving of the wavelength of the recording beam and of its incidence angle, pointing out the high information content of the recorded spot. A theoretical model is presented which satisfactorily explains the observed behavior. It takes into account the interaction of structured light with structured matter with the same symmetries and spatial modulation frequencies close to each other. This result shows a feature of the interaction between structured light and structured matter which has not been explored yet. PMID:27192262

  1. Phase shifting diffraction interferometer

    DOEpatents

    Sommargren, Gary E.

    1996-01-01

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

  2. Phase shifting diffraction interferometer

    DOEpatents

    Sommargren, G.E.

    1996-08-29

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of {lambda}/1000 where {lambda} is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about {lambda}/50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms. 8 figs.

  3. Multilayer diffraction grating

    DOEpatents

    Barbee, Jr., Troy W.

    1990-01-01

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages.

  4. Multilayer diffraction grating

    DOEpatents

    Barbee, T.W. Jr.

    1990-04-10

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages. 2 figs.

  5. Dichroic Coherent Diffractive Imaging

    NASA Astrophysics Data System (ADS)

    Tripathi, Ashish

    Understanding electronic structure at nanometer resolution is crucial to understanding physics such as phase separation and emergent behavior in correlated electron materials. Nondestructive probes which have the ability to see beyond surfaces on nanometer length and sub-picosecond time scales can greatly enhance our understanding of these systems and will impact development of future technologies, such as magnetic storage. Polarized x-rays are an appealing choice of probe due to their penetrating power, elemental and magnetic specificity, and high spatial resolution. The resolution of traditional x-ray microscopy is limited by the nanometer precision required to fabricate x-ray optics. In this thesis, a novel approach to lensless imaging of an extended magnetic nanostructure is presented. We demonstrate this approach by imaging ferrimagnetic "maze" domains in a Gd/Fe multilayer with perpendicular anisotropy. A series of dichroic coherent diffraction patterns, ptychographically recorded, are numerically inverted using non-convex and non-linear optimization theory, and we follow the magnetic domain configuration evolution through part of its magnetization hysteresis loop by applying an external magnetic field. Unlike holographic methods, it does not require a reference wave or precision optics, and so is a far simpler experiment. In addition, it enables the imaging of samples with arbitrarily large spatial dimensions, at a spatial resolution limited solely by the coherent x-ray flux and wavelength. It can readily be extended to other non-magnetic systems that exhibit circular or linear dichroism. This approach is scalable to imaging with diffraction-limited resolution, a prospect rapidly becoming a reality in view of the new generation of phenomenally brilliant x-ray sources.

  6. Dual focus diffractive optical element with extended depth of focus

    NASA Astrophysics Data System (ADS)

    Uno, Katsuhiro; Shimizu, Isao

    2014-09-01

    A dual focus property and an extended depth of focus were verified by a new type of diffractive lens displaying on liquid crystal on silicon (LCoS) devices. This type of lens is useful to read information on multilayer optical discs and tilted discs. The radial undulation of the phase groove on the diffractive lens gave the dual focus nature. The focal extension was performed by combining the dual focus lens with the axilens that was invented for expanding the depth of focus. The number of undulations did not affect the intensity along the optical axis but the central spot of the diffraction pattern.

  7. Design and demonstration of broadband thin planar diffractive acoustic lenses

    SciTech Connect

    Wang, Wenqi; Xie, Yangbo; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A.

    2014-09-08

    We present here two diffractive acoustic lenses with subwavelength thickness, planar profile, and broad operation bandwidth. Tapered labyrinthine unit cells with their inherently broadband effective material properties are exploited in our design. Both the measured and the simulated results are showcased to demonstrate the lensing effect over more than 40% of the central frequency. The focusing of a propagating Gaussian modulated sinusoidal pulse is also demonstrated. This work paves the way for designing diffractive acoustic lenses and more generalized phase engineering diffractive elements with labyrinthine acoustic metamaterials.

  8. Diffraction-based optical correlator

    NASA Technical Reports Server (NTRS)

    Spremo, Stevan M. (Inventor); Fuhr, Peter L. (Inventor); Schipper, John F. (Inventor)

    2005-01-01

    Method and system for wavelength-based processing of a light beam. A light beam, produced at a chemical or physical reaction site and having at least first and second wavelengths, ?1 and ?2, is received and diffracted at a first diffraction grating to provide first and second diffracted beams, which are received and analyzed in terms of wavelength and/or time at two spaced apart light detectors. In a second embodiment, light from first and second sources is diffracted and compared in terms of wavelength and/or time to determine if the two beams arise from the same source. In a third embodiment, a light beam is split and diffracted and passed through first and second environments to study differential effects. In a fourth embodiment, diffracted light beam components, having first and second wavelengths, are received sequentially at a reaction site to determine whether a specified reaction is promoted, based on order of receipt of the beams. In a fifth embodiment, a cylindrically shaped diffraction grating (uniform or chirped) is rotated and translated to provide a sequence of diffracted beams with different wavelengths. In a sixth embodiment, incident light, representing one or more symbols, is successively diffracted from first and second diffraction gratings and is received at different light detectors, depending upon the wavelengths present in the incident light.

  9. Detonation diffraction in gases

    SciTech Connect

    Pintgen, F.; Shepherd, J.E.

    2009-03-15

    We have experimentally investigated detonation diffraction out of a round tube into an unconfined half-space. The focus of our study is examining how the extent of detonation cellular instability influences the quantitative and qualitative features of diffraction. Detailed quantitative and qualitative measurements were obtained through simultaneous schlieren imaging, multiple-exposure chemiluminescence imaging, and planar laser-induced fluorescence imaging of OH molecules. Two types of stoichiometric mixtures, highly diluted H{sub 2}-O{sub 2}-Ar and H{sub 2}-N{sub 2}O, were studied in the sub-critical, critical and super-critical regime. These mixture types represent extreme cases in the classification of cellular instability with highly diluted H{sub 2}-O{sub 2}-Ar mixtures having very regular instability structures and H{sub 2}-N{sub 2}O having very irregular instability structures. The most striking differences between the mixtures occur in the sub-critical and critical regimes, for which the detonation fails to transition into the unconfined half-space. For the H{sub 2}-O{sub 2}-Ar mixture, the velocity on the center line was found to decay significantly slower than for the H{sub 2}-N{sub 2}O mixture. In case of the H{sub 2}-O{sub 2}-Ar mixture, it was evident from simultaneous schlieren-fluorescence images that the reaction front was coupled to the lead shock front up to 2.3 tube diameters from the exit plane. For the H{sub 2}-N{sub 2}O mixture, the reaction front velocity decreased to 60% of the corresponding Chapman-Jouguet value at 1.1 tube diameters from the tube exit plane. A geometric acoustic model showed that the observed differences in failure patterns are not caused by the differences in thermodynamic properties of the two mixtures but is linked to the larger effective activation energy and critical decay time in the H{sub 2}-N{sub 2}O mixture as compared to the H{sub 2}-O{sub 2}-Ar mixture. The re-initiation events appear similar for the two

  10. Higgs boson at LHC: a diffractive opportunity

    SciTech Connect

    Ducati, M. B. Gay; Silveira, G. G.

    2009-03-23

    An alternative process is presented for diffractive Higgs boson production in peripheral pp collisions, where the particles interact through the Double Pomeron Exchange. The event rate is computed as a central-rapidity distribution for Tevatron and LHC energies leading to a result around 0.6 pb, higher than the predictions from previous approaches. Therefore, this result arises as an enhanced signal for the detection of the Higgs boson in hadron colliders. The predictions for the Higgs boson photoproduction are compared to the ones obtained from a similar approach proposed by the Durham group, enabling an analysis of the future developments of its application to pp and AA collisions.

  11. Study of optical Laue diffraction

    SciTech Connect

    Chakravarthy, Giridhar E-mail: aloksharan@email.com; Allam, Srinivasa Rao E-mail: aloksharan@email.com; Satyanarayana, S. V. M. E-mail: aloksharan@email.com; Sharan, Alok E-mail: aloksharan@email.com

    2014-10-15

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  12. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, Antonio J.; Butler, Michael A.; Sinclair, Michael B.; Senturia, Stephen D.

    1998-01-01

    An electrically-programmable diffraction grating. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers).

  13. Recent CMS results on diffraction

    NASA Astrophysics Data System (ADS)

    Benoît, Roland

    2015-03-01

    Recent CMS results on diffraction are presented. These include the measurements of the soft diffractive cross sections, of the forward rapidity gap cross section, of the diffractive dijet cross section, the measurement of a large rapidity gap in W and Z boson events and the measurement of the pseudorapidity distribution of charged particles in a single diffractive enhanced sample. This last measurement is the first common result of the CMS and TOTEM collaborations. Some prospects of common CMS-TOTEM data taking are also discussed.

  14. Results on diffraction at CDF

    SciTech Connect

    Wyatt, A.

    2003-10-27

    In run I CDF made an extensive range of measurements studying diffractive processes. In run II these measurements can be extended using improved triggering, new detectors and larger data samples. In these proceedings run II measurements of single diffractive dijet production and double pomeron exchange production of dijets are presented.

  15. Computer Simulation of Diffraction Patterns.

    ERIC Educational Resources Information Center

    Dodd, N. A.

    1983-01-01

    Describes an Apple computer program (listing available from author) which simulates Fraunhofer and Fresnel diffraction using vector addition techniques (vector chaining) and allows user to experiment with different shaped multiple apertures. Graphics output include vector resultants, phase difference, diffraction patterns, and the Cornu spiral…

  16. Diffractive Higgs boson photoproduction in {gamma}p process

    SciTech Connect

    Ducati, M. B. Gay; Silveira, G. G.

    2008-12-01

    We explore an alternative process for diffractive Higgs boson production in peripheral pp collisions arising from double Pomeron exchange in photon-proton interaction. We introduce the impact factor formalism in order to enable the gluon ladder exchange in the photon-proton subprocess, and to permit central Higgs production. The event rate for diffractive Higgs production in central rapidity is estimated to be about 0.6 pb at Tevatron and LHC energies. This result is higher than predictions from other approaches of diffractive Higgs production, showing that the alternative production process leads to an enhanced signal for the detection of the Higgs boson at hadron colliders. Our results are compared with those obtained from a similar approach proposed by the Durham Group. In this way, we may examine future developments in its application to pp and AA collisions.

  17. Diffractive dissociation including Pomeron loops in zero transverse dimensions

    NASA Astrophysics Data System (ADS)

    Shoshi, Arif I.; Xiao, Bo-Wen

    2007-03-01

    We have recently studied the QCD pomeron loop evolution equations in zero transverse dimensions [Phys. Rev. D 73, 094014 (2006)PRVDAQ0556-282110.1103/PhysRevD.73.094014]. Using the techniques developed in [Phys. Rev. D 73, 094014 (2006)PRVDAQ0556-282110.1103/PhysRevD.73.094014] together with the AGK cutting rules, we present a calculation of single, double and central diffractive cross sections (for large diffractive masses and large rapidity gaps) in zero transverse dimensions in which all dominant pomeron loop graphs are consistently summed. We find that the diffractive cross sections unitarise at large energies and that they are suppressed by powers of αs. Our calculation is expected to expose some of the diffractive physics in hadron-hadron collisions at high energy.

  18. Systematic studies of the centrality and {radical}(s{sub {sub N}}{sub {sub N}}) dependence of the dE{sub T}/d{eta} and dN{sub ch}/d{eta} in heavy ion collisions at midrapidity

    SciTech Connect

    Adler, S.S.; Aidala, C.; Aronson, S.H.; Chujo, T.; David, G.; Desmond, E.J.; Ewell, L.; Franz, A.; Guryn, W.; Haggerty, J.S.; Harvey, M.; Johnson, B.M.; Kistenev, E.; Kroon, P.J.; Makdisi, Y.I.; Mioduszewski, S.; Mitchell, J.T.; Morrison, D.P.; O'Brien, E.; Pinkenburg, C.

    2005-03-01

    The PHENIX experiment at the relativistic heavy ion collider (RHIC) has measured transverse energy and charged particle multiplicity at midrapidity in Au+Au collisions at center-of-mass energies {radical}(s{sub NN})=19.6,130, and 200 GeV as a function of centrality. The presented results are compared to measurements from other RHIC experiments and experiments at lower energies. The {radical}(s{sub NN}) dependence of dE{sub T}/d{eta} and dN{sub ch}/d{eta} per pair of participants is consistent with logarithmic scaling for the most central events. The centrality dependence of dE{sub T}/d{eta} and dN{sub ch}/d{eta} is similar at all measured incident energies. At RHIC energies, the ratio of transverse energy per charged particle was found to be independent of centrality and growing slowly with {radical}(s{sub NN}). A survey of comparisons between the data and available theoretical models is also presented.

  19. Keyhole electron diffractive imaging (KEDI).

    PubMed

    De Caro, Liberato; Carlino, Elvio; Vittoria, Fabio Alessio; Siliqi, Dritan; Giannini, Cinzia

    2012-11-01

    Electron diffractive imaging (EDI) relies on combining information from the high-resolution transmission electron microscopy image of an isolated kinematically diffracting nano-particle with the corresponding nano-electron diffraction pattern. Phase-retrieval algorithms allow one to derive the phase, lost in the acquisition of the diffraction pattern, to visualize the actual atomic projected potential within the specimen at sub-ångström resolution, overcoming limitations due to the electron lens aberrations. Here the approach is generalized to study extended crystalline specimens. The new technique has been called keyhole electron diffractive imaging (KEDI) because it aims to investigate nano-regions of extended specimens at sub-ångström resolution by properly confining the illuminated area. Some basic issues of retrieving phase information from the EDI/KEDI measured diffracted amplitudes are discussed. By using the generalized Shannon sampling theorem it is shown that whenever suitable oversampling conditions are satisfied, EDI/KEDI diffraction patterns can contain enough information to lead to reliable phase retrieval of the unknown specimen electrostatic potential. Hence, the KEDI method has been demonstrated by simulations and experiments performed on an Si crystal cross section in the [112] zone-axis orientation, achieving a resolution of 71 pm. PMID:23075611

  20. Electromagnetic diffraction efficiencies for plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Marathay, A. S.; Shrode, T. E.

    1973-01-01

    Results are presented of research activities on holographic grating research. A large portion of this work was performed using rigorous vector diffraction theory, therefore, the necessary theory has been included in this report. The diffraction efficiency studies were continued using programs based on a rigorous theory. The simultaneous occurrence of high diffraction efficiencies and the phenomenon of double Wood's anomalies is demonstrated along with a graphic method for determining the necessary grating parameters. Also, an analytical solution for a grating profile that is perfectly blazed is obtained. The performance of the perfectly blazed grating profile is shown to be significantly better than grating profiles previously studied. Finally, a proposed method is described for the analysis of coarse echelle gratings using rigorous vector diffraction that is currently being developed.

  1. Spatiotemporal optical pulse transformation by a resonant diffraction grating

    SciTech Connect

    Golovastikov, N. V.; Bykov, D. A. Doskolovich, L. L. Soifer, V. A.

    2015-11-15

    The diffraction of a spatiotemporal optical pulse by a resonant diffraction grating is considered. The pulse diffraction is described in terms of the signal (the spatiotemporal incident pulse envelope) passage through a linear system. An analytic approximation in the form of a rational function of two variables corresponding to the angular and spatial frequencies has been obtained for the transfer function of the system. A hyperbolic partial differential equation describing the general form of the incident pulse envelope transformation upon diffraction by a resonant diffraction grating has been derived from the transfer function. A solution of this equation has been obtained for the case of normal incidence of a pulse with a central frequency lying near the guided-mode resonance of a diffraction structure. The presented results of numerical simulations of pulse diffraction by a resonant grating show profound changes in the pulse envelope shape that closely correspond to the proposed theoretical description. The results of the paper can be applied in creating new devices for optical pulse shape transformation, in optical information processing problems, and analog optical computations.

  2. Diffraction dissociation at the LHC

    NASA Astrophysics Data System (ADS)

    Jenkovszky, László; Orava, Risto; Salii, Andrii

    2013-04-01

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  3. Diffraction dissociation at the LHC

    SciTech Connect

    Jenkovszky, Laszlo; Orava, Risto; Salii, Andrii

    2013-04-15

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  4. Diffraction techniques in engineering applications

    SciTech Connect

    Kozarczek, K.J.; Hubbard, C.R.; Watkins, T.R.; Wang, X.L.; Spooner, S.

    1995-12-31

    Diffraction techniques applied to crystalline materials provide quantitative information about the crystallographic structure and mechanical condition of the material. Those two characteristics influence the chemical, physical, and mechanical properties of a Component. A concerted application of x-ray and neutron diffraction allows one to comprehensively study the bulk and subsurface variations of such material characteristics as crystallographic texture, residual stress, and cold work. The Residual Stress User Center at the Oak Ridge National Laboratory offers academic and industrial researchers both neutron and x-ray diffraction capabilities. Recent examples of the application of work related to thin film, metal, ceramic and composite material technologies are presented.

  5. X-Ray Diffraction Apparatus

    NASA Technical Reports Server (NTRS)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  6. Femtosecond single-electron diffraction

    PubMed Central

    Lahme, S.; Kealhofer, C.; Krausz, F.; Baum, P.

    2014-01-01

    Ultrafast electron diffraction allows the tracking of atomic motion in real time, but space charge effects within dense electron packets are a problem for temporal resolution. Here, we report on time-resolved pump-probe diffraction using femtosecond single-electron pulses that are free from intra-pulse Coulomb interactions over the entire trajectory from the source to the detector. Sufficient average electron current is achieved at repetition rates of hundreds of kHz. Thermal load on the sample is avoided by minimizing the pump-probe area and by maximizing heat diffusion. Time-resolved diffraction from fibrous graphite polycrystals reveals coherent acoustic phonons in a nanometer-thick grain ensemble with a signal-to-noise level comparable to conventional multi-electron experiments. These results demonstrate the feasibility of pump-probe diffraction in the single-electron regime, where simulations indicate compressibility of the pulses down to few-femtosecond and attosecond duration. PMID:26798778

  7. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, A.J.; Butler, M.A.; Sinclair, M.B.; Senturia, S.D.

    1998-05-26

    An electrically-programmable diffraction grating is disclosed. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers). 14 figs.

  8. Fresnel diffraction by spherical obstacles

    NASA Technical Reports Server (NTRS)

    Hovenac, Edward A.

    1989-01-01

    Lommel functions were used to solve the Fresnel-Kirchhoff diffraction integral for the case of a spherical obstacle. Comparisons were made between Fresnel diffraction theory and Mie scattering theory. Fresnel theory is then compared to experimental data. Experiment and theory typically deviated from one another by less than 10 percent. A unique experimental setup using mercury spheres suspended in a viscous fluid significantly reduced optical noise. The major source of error was due to the Gaussian-shaped laser beam.

  9. New CDF results on diffraction

    SciTech Connect

    Mesropian, Christina; /Rockefeller U.

    2006-12-01

    We report new diffraction results obtained by the CDF collaboration in proton-antiproton collisions at the Fermilab Tevatron collider at {radical}s=1.96 TeV. The first experimental evidence of exclusive dijet and diphoton production is presented. The exclusive results are discussed in context of the exclusive Higgs production at LHC. We also present the measurement of the Q{sup 2} and t dependence of the diffractive structure function.

  10. Flooding in Central China

    NASA Technical Reports Server (NTRS)

    2002-01-01

    During the summer of 2002, frequent, heavy rains gave rise to floods and landslides throughout China that have killed over 1,000 people and affected millions. This false-color image of the western Yangtze River and Dongting Lake in central China was acquired on August 21, 2002, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. (right) The latest flooding crisis in China centers on Dingtong Lake in the center of the image. Heavy rains have caused it to swell over its banks and swamp lakefront towns in the province of Hunan. As of August 23, 2002, more than 250,000 people have been evacuated, and over one million people have been brought in to fortify the dikes around the lake. Normally the lake would appear much smaller and more defined in the MODIS image. Credit: Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC.

  11. Diffraction efficiency analysis for multi-level diffractive optical elements

    SciTech Connect

    Erteza, I.A.

    1995-11-01

    Passive optical components can be broken down into two main groups: Refractive elements and diffractive elements. With recent advances in manufacturing technologies, diffractive optical elements are becoming increasingly more prevalent in optical systems. It is therefore important to be able to understand and model the behavior of these elements. In this report, we present a thorough analysis of a completely general diffractive optical element (DOE). The main goal of the analysis is to understand the diffraction efficiency and power distribution of the various modes affected by the DOE. This is critical to understanding cross talk and power issues when these elements are used in actual systems. As mentioned, the model is based on a completely general scenario for a DOE. This allows the user to specify the details to model a wide variety of diffractive elements. The analysis is implemented straightforwardly in Mathematica. This report includes the development of the analysis, the Mathematica implementation of the model and several examples using the Mathematical analysis tool. It is intended that this tool be a building block for more specialized analyses.

  12. Heavy Stars Thrive among Heavy Elements

    NASA Astrophysics Data System (ADS)

    2002-08-01

    , with a sprinkling of the light element lithium. At our epoch, the visible ("baryonic") matter in the Universe still mostly consists of hydrogen and helium. However, progressively heavier elements have been built up via fusion processes in the interior of stars ever since the Big Bang. Some of the heaviest elements are also produced when massive stars die in gigantic stellar explosions, observed as "supernovae". This gradual process, referred to as "chemical evolution" , occurs with different speeds in different regions of the Universe, being fastest in those regions where star formation is most intense. In the relatively "quiet" region of the Milky Way galaxy where our Solar System was born some 4,600 million years ago, it took nearly 10,000 million years to produce all the heavy elements now found in our neighbourhood . Contrarily, in the innermost regions ( the "nuclei" ) of normal galaxies and especially in so-called "active galaxies", the same or even higher heavy-element "enrichment" levels were reached in much shorter time, less than about 1,000 to 2,000 million years. This is the result of observations of particularly active galaxy nuclei ("quasars") in the distant (i.e., early) Universe. Star formation in highly enriched environments Little is presently known about such highly enriched environments. Since astronomers refer to elements heavier than hydrogen and helium as "metals" , they talk about "metal-rich" regions . This is readily observable from the presence of strong lines from heavier elements in the spectra of the interstellar gas in such regions. A central, still unresolved question is whether under such special conditions, stars can still form with the same diversity of masses, as this happens in other, less extreme areas of the Universe . Indeed, some current theories of star formation and certain indirect observations appear to indicate that very heavy stars - with masses more than 20 - 30 times that of our Sun - could no

  13. Diffraction described by virtual particle momentum exchange: the "diffraction force"

    NASA Astrophysics Data System (ADS)

    Mobley, Michael J.

    2011-09-01

    Particle diffraction can be described by an ensemble of particle paths determined through a Fourier analysis of a scattering lattice where the momentum exchange probabilities are defined at the location of scattering, not the point of detection. This description is compatible with optical wave theories and quantum particle models and provides deeper insights to the nature of quantum uncertainty. In this paper the Rayleigh-Sommerfeld and Fresnel-Kirchoff theories are analyzed for diffraction by a narrow slit and a straight edge to demonstrate the dependence of particle scattering on the distance of virtual particle exchange. The quantized momentum exchange is defined by the Heisenberg uncertainty principle and is consistent with the formalism of QED. This exchange of momentum manifests the "diffraction force" that appears to be a universal construct as it applies to neutral and charged particles. This analysis indicates virtual particles might form an exchange channel that bridges the space of momentum exchange.

  14. Electromagnetic diffraction efficiencies for plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Marathay, A. S.; Shrode, T. E.

    1974-01-01

    The theory and computer programs, based on electromagnetic theory, for the analysis and design of echelle gratings were developed. The gratings are designed for instruments that operate in the ultraviolet portion of the spectrum. The theory was developed so that the resulting computer programs will be able to analyze deep (up to 30 wavelengths) gratings by including as many as 100 real or homogeneous diffraction orders. The program calculates the complex amplitude coefficient for each of the diffracted orders. A check on the numerical method used to solve the integral equations is provided by a conservation of energy calculation.

  15. Electromagnetic processes in relativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Bertulani, C. A.; Baur, G.

    1986-10-01

    Electromagnetic effects in relativistic heavy ion collisions with impact parameter larger than the sum of the nuclear radii are studied using the virtual photon method. With increasing value of the relativistic parameter γ the hardness of the virtual photon spectrum increases. This leads to interesting new effects which will also have to be considered in the design of future relativistic heavy ion machines and experiments. The excitation of high-lying giant E1 and E2 multipole resonances is calculated as well as electromagnetic pion production. Coulomb bremsstrahlung is calculated and compared to the bremsstrahlung emitted in the more violent central nuclear collisions. K-shell ionization and electron-positron pair production is studied. The latter process has a very large cross section for heavy ions and contributes significantly to the stopping power of relativistic heavy ions in a dense medium.

  16. Exclusive diffractive photon bremsstrahlung at the LHC

    NASA Astrophysics Data System (ADS)

    Lebiedowicz, Piotr; Szczurek, Antoni

    2013-06-01

    We calculate differential distributions for the pp→ppγ reaction at the LHC energy s=14TeV. We consider diffractive classical bremsstrahlung mechanisms including effects of the non-point-like nature of protons. In addition, we take into account (vector meson)-pomeron, photon-pion, and photon-pomeron exchange processes for the first time in the literature. Predictions for the total cross section and several observables related to these processes, e.g., differential distributions in pseudorapidities and transverse momenta of photons or protons are shown and discussed. The integrated diffractive bremsstrahlung cross section (Eγ>100GeV) is only of the order of μb. We try to identify regions of the phase space where one of the mechanisms dominates. The classical bremsstrahlung dominates at large forward/backward photon pseudorapidities, close to the pseudorapidities of scattered protons. In contrast, the photon-pomeron (pomeron-photon) mechanism dominates at midrapidities but the related cross section is rather small. In comparison the virtual-omega-rescattering mechanism contributes at smaller angles of photons (larger photon rapidities). Photons in the forward/backward region can be measured by the Zero Degree Calorimeters installed in experiments at the LHC while the midrapidity photons are difficult to measure (small cross section, small photon transverse momenta). Protons could be measured by the ALFA detector (ATLAS) or TOTEM detector at CMS. The exclusivity could be checked with the help of main central detectors.

  17. Lensless reflective point diffraction interferometer.

    PubMed

    Zhu, Wenhua; Chen, Lei; Zheng, Donghui; Yang, Ying; Han, Zhigang; Li, Jinpeng

    2016-07-01

    A lensless reflective point diffraction interferometer (LRPDI) is proposed for dynamic wavefront measurement. The point diffraction interferometer is integrated on a small substrate with properly designed thin film, which is used for generating the interferogram with high carrier frequency at a CCD target. By lensless imaging, the complex amplitude at the CCD target can be propagated to the conjugated plane of the exit pupil of an incident wavefront, which not only avoids the edge diffraction in the interferogram, but also eliminates systematic error. The accuracy of LRPDI is demonstrated by simulation and experiment, and a precision better than 1/150 wavelength is achieved. The new design with lensless imaging processing is suitable for dynamic wavefront measurement. PMID:27409204

  18. Electron diffraction by plasmon waves

    NASA Astrophysics Data System (ADS)

    García de Abajo, F. J.; Barwick, B.; Carbone, F.

    2016-07-01

    An electron beam traversing a structured plasmonic field is shown to undergo diffraction with characteristic angular patterns of both elastic and inelastic outgoing electron components. In particular, a plasmonic grating (e.g., a standing wave formed by two counterpropagating plasmons in a thin film) produces diffraction orders of the same parity as the net number of exchanged plasmons. Large diffracted beam fractions are predicted to occur for realistic plasmon intensities in attainable geometries due to a combination of phase and amplitude changes locally imprinted on the passing electron wave. Our study opens vistas in the study of multiphoton exchanges between electron beams and evanescent optical fields with unexplored effects related to the transversal component of the electron wave function.

  19. Imaging the proton via hard exclusive production in diffractive pp scattering

    SciTech Connect

    Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss

    2007-05-21

    We discuss the prospects for probing Generalized Parton Distributions (GPDs) via exclusive production of a high-mass system (H = heavy quarkonium, di-photon, di-jet, Higgs boson) in diffractive pp scattering, pp -> p + H + p. In such processes the interplay of hard and soft interactions gives rise to a diffraction pattern in the final-state proton transverse momenta, which is sensitive to the transverse spatial distribution of partons in the colliding protons. We comment on the plans for diffractive pp measurements at RHIC and LHC. Such studies could complement future measurements of GPDs in hard exclusive ep scattering (JLab, COMPASS, EIC).

  20. Boundary diffraction wave integrals for diffraction modeling of external occulters.

    PubMed

    Cady, Eric

    2012-07-01

    An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly model these effects. We present a fast method for the calculation of electric fields following an occulter, based on the concept of the boundary diffraction wave: the 2D structure of the occulter is reduced to a 1D edge integral which directly incorporates the occulter shape, and which can be easily adjusted to include changes in occulter position and shape, as well as the effects of sources-such as exoplanets-which arrive off-axis to the occulter. The structure of a typical implementation of the algorithm is included. PMID:22772218

  1. Distributed etched diffraction grating demultiplexer

    NASA Astrophysics Data System (ADS)

    Jafari, Amir

    This doctoral thesis studies the concept of a distributed etched diffraction grating (DEDG) and presents a methodology to engineer the spectral response of the device. The design which incorporates a distributed Bragg reflector (DBR) at the facets of a conventional etched diffraction grating demultiplexer promises for a superior performance in multiple aspects. Where in a conventional etched diffraction grating, smooth vertical deep etched walls are required in order to realize a low insertion loss device; in the DEDG such requirement is significantly mitigated. Deep etched walls are replaced with shallowly etched diffraction grating facets followed by a DBR structure and as a result devices with significantly lower insertion loss are achievable. The feasibility of the application of DEDG as a wavelength demultiplexer was demonstrated through fabrication and characterization of a prototype device. The proof of concept device was fabricated using the state of the art deep UV optical lithography and reactive ion etching in a nano-photonic silicon-on-insulator (SOI) material platform. The fabricated device was then characterized in the lab. Furthermore, incorporation of the DBR structure at the facets of the conventional etched diffraction grating decouples the reflection and diffraction functionalities, rendering the DEDG suitable for spectral response engineering. According to the application, the output spectral response of the device can be tailored through careful design and optimization of the incorporated DBR. In this thesis, through numerical simulations we have shown that functionalities such as polarization independent performance and at top insertion loss envelop are viable. A methodology to engineer the spectral response of the DEDG is discussed in details.

  2. Neutron diffraction on pulsed sources

    NASA Astrophysics Data System (ADS)

    Aksenov, V. L.; Balagurov, A. M.

    2016-03-01

    The current capabilities of and major scientific problems solved by time-of-flight neutron diffraction are reviewed. The reasons for the rapid development of the method over the last two decades have been mainly the emergence of third-generation pulsed sources with a megawatt time-averaged power and advances in neutron optical devices and detector systems. The paper discusses some historical aspects of time-of-flight neutron diffraction and examines the contribution to this method from F L Shapiro, the centennial of whose birth was celebrated in 2015. The state of the art with respect to neutron sources for studies on extracted beams is reviewed in a special section.

  3. High-pressure neutron diffraction

    SciTech Connect

    Xu, Hongwu

    2011-01-10

    This lecture will cover progress and prospect of applications of high-pressure neutron diffraction techniques to Earth and materials sciences. I will first introduce general high-pressure research topics and available in-situ high-pressure techniques. Then I'll talk about high-pressure neutron diffraction techniques using two types of pressure cells: fluid-driven and anvil-type cells. Lastly, I will give several case studies using these techniques, particularly, those on hydrogen-bearing materials and magnetic transitions.

  4. Diffraction encoded position measuring apparatus

    DOEpatents

    Tansey, Richard J.

    1991-01-01

    When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection.

  5. Diffraction encoded position measuring apparatus

    DOEpatents

    Tansey, R.J.

    1991-09-24

    When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection. 3 figures.

  6. Ellipsometry of diffractive insect reflectors

    NASA Astrophysics Data System (ADS)

    Brink, D. J.; Lee, M. E.

    1996-04-01

    Scales on the wings of certain insects, such as Trichoplusia orichalcea, exhibit a surface microstructure resembling a fine diffraction grating. Diffraction of incident light by this structure is responsible for many of the optical properties of the wings of this moth, such as the metallic yellow color and the almost-specular reflection and polarization properties of the scattered radiation. It is shown that by the use of null ellipsometry the polarization characteristics can be used to obtain the optical constants of the scale material. Theoretical considerations and suitable experimental conditions are discussed and evaluated.

  7. Subwavelength diffractive color beam combiner.

    PubMed

    Petrov, Nikolai I; Nikitin, Vladislav G; Danilov, Viktor A; Popov, Vladimir V; Usievich, Boris A

    2014-09-01

    A high-efficiency subwavelength diffractive beam combiner operating in a visible spectral range is designed, fabricated, and demonstrated. Such a device combines red, green, and blue color beams into one output light beam. Diffraction efficiencies of different types of gratings are calculated for various materials, incidence angles, and polarizations of light. It is shown that the plasmon resonance via a grating coupling occurs at the determined conditions. Subwavelength gratings with a period of 400 nm are fabricated and tested using laser and laser diode sources. PMID:25321371

  8. Charged Particle Multiplicity and Open Heavy Flavor Physics in Relativistic Heavy Ion Collisions at the LHC

    NASA Astrophysics Data System (ADS)

    Chen, Yujiao

    In this thesis, two independent measurements are presented: the measurements of centrality dependence and pseudo-rapidity dependence of charged particle multiplicities, and the measurements of centrality dependence of open heavy flavor suppression. These measurements are carried out with the Pb+Pb collisions data at the LHC energy sNN = 2.76 TeV with the ATLAS detector. For the charged particle measurements, charged particles are reconstructed with two algorithms (2-point "tracklet" and full tracking) from the pixel detector only. Measurements are presented of the per-event charged particle density distribution, dNch /deta and the average charged particle multiplicity in the pseudo-rapidity interval |eta| <0.5 in several intervals of collision centrality. The results are compared to previous mid-rapidity measurements at the LHC and RHIC. The variation of the mid-rapidity charged particle yield per colliding nucleon pair with the number of participants is consistent with the lower sNN results measured at RHIC. The shape of the dNch/deta distribution is found to be independent of centrality within the systematic uncertainties of the measurement. For the open heavy flavor suppression measurements, muons identified by the muon spectrometer are classified as heavy flavor decays and background contributions by using a fitting procedure with templates from Monte Carlo samples. Results are presented for the per-event muon yield as a function of muon transverse momentum, p T, over the range of 4 < pT < 14 GeV. Over that momentum range single muon production results largely from heavy quark decays. The centrality dependence of the muon yields is characterized by the "central to peripheral" ratio, RCP. Using this measure, muon production from heavy quark decays is found to be suppressed by a centrality-dependent factor that increases smoothly from peripheral to central collisions. Muon production is suppressed by approximately a factor of two in central collisions relative to

  9. New HMI hard X-ray Diffraction Beamlines at BESSY

    SciTech Connect

    Denks, I. A.; Genzel, C.; Dudzik, E.; Feyerherm, R.; Klaus, M.; Wagener, G.

    2007-01-19

    Since April 2005 the Hahn-Meitner-Institute is operating two new beamlines for energy dispersive diffraction experiments (EDDI) and for (resonant) magnetic scattering (MAGS) at BESSY. The source for both beamlines is a superconducting 7 T multipole wiggler which provides hard X-ray photons with energies between 4 and 150 keV. The EDDI beamline uses the white beam and is intended for residual stress measurements on small samples as well as heavy engineering parts. The MAGS beamline delivers a focussed monochromatic beam with photon fluxes in the 1012 (s 100 mA 0.1 % bandwidth)-1 range at energies from 4 to 30 keV. It is equipped for single crystal diffraction and resonant (magnetic) scattering experiments as well as for the study of thin films, micro-, and nanostructures in materials science.

  10. New HMI hard X-ray Diffraction Beamlines at BESSY

    NASA Astrophysics Data System (ADS)

    Denks, I. A.; Genzel, C.; Dudzik, E.; Feyerherm, R.; Klaus, M.; Wagener, G.

    2007-01-01

    Since April 2005 the Hahn-Meitner-Institute is operating two new beamlines for energy dispersive diffraction experiments (EDDI) and for (resonant) magnetic scattering (MAGS) at BESSY. The source for both beamlines is a superconducting 7 T multipole wiggler which provides hard X-ray photons with energies between 4 and 150 keV. The EDDI beamline uses the white beam and is intended for residual stress measurements on small samples as well as heavy engineering parts. The MAGS beamline delivers a focussed monochromatic beam with photon fluxes in the 1012 (s 100 mA 0.1 % bandwidth)-1 range at energies from 4 to 30 keV. It is equipped for single crystal diffraction and resonant (magnetic) scattering experiments as well as for the study of thin films, micro-, and nanostructures in materials science.

  11. Fresnel Diffraction for CTR Microbunching

    SciTech Connect

    Tikhoplav, R.; Knyazik, A.; Rosenzweig, J. B.; Andonian, G.

    2009-01-22

    Laser beams of high intensities are routinely used for IFEL experiments. Such beams can potentially destroy microbunching diagnostic tools such as coherent transition radiation foils due to their low damage thresholds. Near-field Fresnel diffraction scheme for termination of CO{sub 2} laser beam has been experimentally studied and is presented in this paper. Novel THz camera was utilized for such study.

  12. Atom Pair Distribution Functions of Liquid Water at 25circC from Neutron Diffraction

    NASA Astrophysics Data System (ADS)

    Narten, A. H.; Thiessen, W. E.; Blum, L.

    1982-09-01

    The structure of liquid water is described by three atom pair distribution functions gOO(r), gOH(r), and gHH(r). These functions have now been derived from neutron diffraction data on four mixtures of light and heavy water. They will provide a crucial and sensitive test for proposed models of liquid water.

  13. Digital diffractive optics: Have diffractive optics entered mainstream industry yet?

    NASA Astrophysics Data System (ADS)

    Kress, Bernard; Hejmadi, Vic

    2010-05-01

    When a new technology is integrated into industry commodity products and consumer electronic devices, and sold worldwide in retail stores, it is usually understood that this technology has then entered the realm of mainstream technology and therefore mainstream industry. Such a leap however does not come cheap, as it has a double edge sword effect: first it becomes democratized and thus massively developed by numerous companies for various applications, but also it becomes a commodity, and thus gets under tremendous pressure to cut down its production and integration costs while not sacrificing to performance. We will show, based on numerous examples extracted from recent industry history, that the field of Diffractive Optics is about to undergo such a major transformation. Such a move has many impacts on all facets of digital diffractive optics technology, from the optical design houses to the micro-optics foundries (for both mastering and volume replication), to the final product integrators or contract manufacturers. The main causes of such a transformation are, as they have been for many other technologies in industry, successive technological bubbles which have carried and lifted up diffractive optics technology within the last decades. These various technological bubbles have been triggered either by real industry needs or by virtual investment hype. Both of these causes will be discussed in the paper. The adjective ""digital"" in "digital diffractive optics" does not refer only, as it is done in digital electronics, to the digital functionality of the element (digital signal processing), but rather to the digital way they are designed (by a digital computer) and fabricated (as wafer level optics using digital masking techniques). However, we can still trace a very strong similarity between the emergence of micro-electronics from analog electronics half a century ago, and the emergence of digital optics from conventional optics today.

  14. Diffraction-Coupled, Phase-Locked Semiconductor Laser Array

    NASA Technical Reports Server (NTRS)

    Katz, Joseph; Yariv, Amnon; Margalit, Shlomo

    1988-01-01

    Stable, narrow far field produced. Array of lasers fabricated on single chip. Individual laser waveguides isolated from each other except in end portions, where diffraction coupling takes place. Radiation pattern far from laser array has single, sharp central lobe when all lasers operate in phase with each other. Shape of lobe does not vary appreciably with array current. Applications include recording, printing, and range finding.

  15. Elliptic and triangular flow of heavy flavor in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Nahrgang, Marlene; Aichelin, Jörg; Bass, Steffen; Gossiaux, Pol Bernard; Werner, Klaus

    2015-01-01

    We investigate the elliptic and the triangular flow of heavy mesons in ultrarelativistic heavy-ion collisions at the BNL Relativistic Heavy-Ion Collider and the CERN Large Hadron Collider (LHC) . The dynamics of heavy quarks is coupled to the locally thermalized and fluid dynamically evolving quark-gluon plasma. The elliptic flow of D mesons and the centrality dependence measured at the LHC is well reproduced for purely collisional and bremsstrahlung interactions. Due to the event-by-event fluctuating initial conditions from the EPOS2 model, the D meson triangular flow is predicted to be nonzero at √{s }=200 GeV and √{s }=2.76 TeV. We study the centrality dependence and quantify the contributions stemming from flow of the light bulk event and the hadronization process. The flow coefficients as responses to the initial eccentricities behave differently for heavy mesons than for light hadrons due to their inertia. Higher-order flow coefficients of heavy flavor become important in order to quantify the degree of thermalization.

  16. dxtbx: the diffraction experiment toolbox.

    PubMed

    Parkhurst, James M; Brewster, Aaron S; Fuentes-Montero, Luis; Waterman, David G; Hattne, Johan; Ashton, Alun W; Echols, Nathaniel; Evans, Gwyndaf; Sauter, Nicholas K; Winter, Graeme

    2014-08-01

    Data formats for recording X-ray diffraction data continue to evolve rapidly to accommodate new detector technologies developed in response to more intense light sources. Processing the data from single-crystal X-ray diffraction experiments therefore requires the ability to read, and correctly interpret, image data and metadata from a variety of instruments employing different experimental representations. Tools that have previously been developed to address this problem have been limited either by a lack of extensibility or by inconsistent treatment of image metadata. The dxtbx software package provides a consistent interface to both image data and experimental models, while supporting a completely generic user-extensible approach to reading the data files. The library is written in a mixture of C++ and Python and is distributed as part of the cctbx under an open-source licence at http://cctbx.sourceforge.net. PMID:25242914

  17. Diffraction Analysis of Solar Coronagraphs

    NASA Astrophysics Data System (ADS)

    Rabin, Douglas M.; gong, qian

    2016-05-01

    The design of a solar coronagraph is predicated on controlling diffracted and scattered light using principles dating back to Bernard Lyot in the 1930’s. The existence of many successful ground- and space-based coronagraphs testifies to our ability to apply these principles in specific cases, but it is difficult to explore a significant range of design parameters because the calculations are tricky and time-consuming. Indeed, scattered light is so design-specific that ad hoc analysis is unavoidable once guidelines from experience are used to create a first-guess system of baffles and low-scatter surfaces. Here we describe a combination of analytic and computational approaches that has the potential to explore coronagraph design space somewhat more systematically with respect to diffracted light.

  18. Diffraction operators in paraxial approach

    NASA Astrophysics Data System (ADS)

    Lasso, William; Navas, Marianela; Añez, Liz; Urdaneta, Romer; Díaz, Leonardo; Torres, César O.

    2014-07-01

    Nowadays, research in the field of science education points to the creation of alternative ways of teaching contents encouraging the development of more elaborate reasoning, where a high degree of abstraction and generalization of scientific knowledge prevails. On that subject, this research shows a didactic alternative proposal for the construction of Fresnel and Fraunhoffer diffraction concepts applying the Fourier transform technique in the study of electromagnetic waves propagation in free space. Curvature transparency and Fourier sphere operators in paraxial approximation are used in order to make the usual laborious mathematical approach easier. The main result shows that the composition of optic metaxial operators results in the discovery of a simpler way out of the standard electromagnetic wave propagation in free space between a transmitter and a receptor separated from a given distance. This allows to state that the didactic proposal shown encourages the construction of Fresnel and Fraunhoffer diffraction concepts in a more effective and easier way than the traditional teaching.

  19. Heavy Stars Thrive among Heavy Elements

    NASA Astrophysics Data System (ADS)

    2002-08-01

    , with a sprinkling of the light element lithium. At our epoch, the visible ("baryonic") matter in the Universe still mostly consists of hydrogen and helium. However, progressively heavier elements have been built up via fusion processes in the interior of stars ever since the Big Bang. Some of the heaviest elements are also produced when massive stars die in gigantic stellar explosions, observed as "supernovae". This gradual process, referred to as "chemical evolution" , occurs with different speeds in different regions of the Universe, being fastest in those regions where star formation is most intense. In the relatively "quiet" region of the Milky Way galaxy where our Solar System was born some 4,600 million years ago, it took nearly 10,000 million years to produce all the heavy elements now found in our neighbourhood . Contrarily, in the innermost regions ( the "nuclei" ) of normal galaxies and especially in so-called "active galaxies", the same or even higher heavy-element "enrichment" levels were reached in much shorter time, less than about 1,000 to 2,000 million years. This is the result of observations of particularly active galaxy nuclei ("quasars") in the distant (i.e., early) Universe. Star formation in highly enriched environments Little is presently known about such highly enriched environments. Since astronomers refer to elements heavier than hydrogen and helium as "metals" , they talk about "metal-rich" regions . This is readily observable from the presence of strong lines from heavier elements in the spectra of the interstellar gas in such regions. A central, still unresolved question is whether under such special conditions, stars can still form with the same diversity of masses, as this happens in other, less extreme areas of the Universe . Indeed, some current theories of star formation and certain indirect observations appear to indicate that very heavy stars - with masses more than 20 - 30 times that of our Sun - could not possibly form in metal

  20. Central line infections - hospitals

    MedlinePlus

    ... infection; CVC - infection; Central venous device - infection; Infection control - central line infection; Nosocomial infection - central line infection; Hospital acquired infection - central line infection; Patient safety - central ...

  1. Diffraction gratings for lighting applications

    NASA Astrophysics Data System (ADS)

    Cornelissen, Hugo J.; de Boer, Dick K. G.; Tukker, Teus

    2013-09-01

    Sub-micron diffraction gratings have been used for two LED illumination applications. One is to create a transparent see through luminaire which can be used to illuminate and read a paper document or e-book. A second is a light sensor that can be used in a feedback loop to control a multicolor LED lamp. Optical design and experimental proof-of-principle are presented.

  2. Industrial applications of neutron diffraction

    SciTech Connect

    Felcher, G.P.

    1989-01-01

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

  3. Diffraction techniques in structural biology.

    PubMed

    Egli, Martin

    2010-06-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the molecular activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy, and neutron diffraction are well established and they have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches, and high-speed computing and visualization, now provide specialists and nonspecialists alike with a steady flow of molecular images of unprecedented detail. The present unit combines a general overview of diffraction methods with a detailed description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis, and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. PMID:20517991

  4. Diffraction Techniques in Structural Biology.

    PubMed

    Egli, Martin

    2016-01-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the molecular activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy, and neutron diffraction are well established and they have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last twenty years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches, and high-speed computing and visualization, now provide specialists and nonspecialists alike with a steady flow of molecular images of unprecedented detail. The present unit combines a general overview of diffraction methods with a detailed description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis, and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. © 2016 by John Wiley & Sons, Inc. PMID:27248784

  5. Vorticity production in shock diffraction

    NASA Astrophysics Data System (ADS)

    Sun, M.; Takayama, K.

    2003-03-01

    The production of vorticity or circulation production in shock wave diffraction over sharp convex corners has been numerically simulated and quantified. The corner angle is varied from 5° to 180°. Total vorticity is represented by the circulation, which is evaluated by integrating the velocity along a path enclosing the perturbed region behind a diffracting shock wave. The increase of circulation in unit time, or the rate of circulation production, depends on the shock strength and wall angle if the effects of viscosity and heat conductivity are neglected. The rate of vorticity production is determined by using a solution-adaptive code, which solves the Euler equations. It is shown that the rate of vorticity production is independent of the computational mesh and numerical scheme by comparing solutions from two different codes. It is found that larger wall angles always enhance the vorticity production. The vorticity production increases sharply when the corner angle is varied from 15° to 45°. However, for corner angles over 90°, the rate of vorticity production hardly increases and reaches to a constant value. Strong shock waves produce vorticity faster in general, except when the slipstream originating from the shallow corner attaches to the downstream wall. It is found that the vorticity produced by the slipstream represents a large proportion of the total vorticity. The slipstream is therefore a more important source of vorticity than baroclinic effects in shock diffraction.

  6. Liquid crystal filled diffraction gratings

    NASA Astrophysics Data System (ADS)

    Jepsen, Mary Lou

    1997-12-01

    Liquid crystal technology is becoming increasingly important for flat displays in electronics, computers and TV. Most liquid crystal displays currently made have as their basic unit, two flat surfaces each coated with a transparent, conductive layer, between which a thin layer of liquid crystals is sandwiched. The work detailed in this dissertation is based on a modification of the basic liquid crystal unit and studies the properties of structures which consist of certain anisotropic liquid crystals confined between a flat substrate and a corrugated one, each substrate being transparent and having a thin trans-parent conductive coating. Without an applied electric field, the refractive indices of the liquid crystal and corrugated substrate do not match, and thus strong diffraction occurs. When an electric field is applied to the device, the liquid crystals are re-oriented so that the refractive indices now match, and the device behaves as a uniform slab of homogeneous material producing no diffraction. Rigorous coupled wave analysis was developed to design the ideal devices and analyze the performance of our experimental ones. 99% diffraction efficiencies in single wavelength polarized illumination are shown to be possible with this class of devices. The best device we fabricated showed a 62% distraction efficiency, as our fabrication process roughened the top surface of the device so that (≃30%) of the incident light was lost to scatter. Several new fabrication processes are proposed to eliminate this scatter problem, and that details of fabrication processes thus far attempted are outlined.

  7. Stretchable diffraction gratings for spectrometry

    NASA Astrophysics Data System (ADS)

    Simonov, Aleksey N.; Grabarnik, Semen; Vdovin, Gleb

    2007-07-01

    We have investigated the possibility of using transparent stretchable diffraction gratings for spectrometric applications. The gratings were fabricated by replication of a triangular-groove master into a transparent viscoelastic. The sample length, and hence the spatial period, can be reversibly changed by mechanical stretching. When used in a monochromator with two slits, the stretchable grating permits scanning the spectral components over the output slit, converting the monochromator into a scanning spectrometer. The spectral resolution of such a spectrometer was found to be limited mainly by the wave-front aberrations due to the grating deformation. A model relating the deformation-induced aberrations in different diffraction orders is presented. In the experiments, a 12-mm long viscoelastic grating with a spatial frequency of 600 line pairs/mm provided a full-width at half-maximum resolution of up to ~1.2 nm in the 580-680 nm spectral range when slowly stretched by a micrometer screw and ~3 nm when repeatedly stretched by a voice coil at 15 Hz. Comparison of aberrations in transmitted and diffracted beams measured by a Shack- Hartmann wave-front sensor showed that astigmatisms caused by stretch-dependent wedge deformation are the main factors limiting the resolution of the viscoelastic-grating-based spectrometer.

  8. Submicron X-ray diffraction

    SciTech Connect

    MacDowell, Alastair; Celestre, Richard; Tamura, Nobumichi; Spolenak, Ralph; Valek, Bryan; Brown, Walter; Bravman, John; Padmore, Howard; Batterman, Boris; Patel, Jamshed

    2000-08-17

    At the Advanced Light Source in Berkeley the authors have instrumented a beam line that is devoted exclusively to x-ray micro diffraction problems. By micro diffraction they mean those classes of problems in Physics and Materials Science that require x-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron sized aluminum metal grains buried under a silicon dioxide insulating layer. The resulting Laue pattern is collected on a large area CCD detector and automatically indexed to yield the grain orientation and deviatoric (distortional) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam, which allows monochromatic light to illuminate the same part of the sample. Measurement of diffracted photon energy allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total strain/stress tensor (6 components) inside each sub-micron sized illuminated volume of the sample.

  9. Diffraction Techniques in Structural Biology

    PubMed Central

    Egli, Martin

    2010-01-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy and neutron diffraction are well established and have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches and high-speed computing and visualization, now provide specialists and non-specialists alike with a steady flow of molecular images of unprecedented detail. The present chapter combines a general overview of diffraction methods with a step-by-step description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. PMID:20517991

  10. Heavy quark masses

    NASA Technical Reports Server (NTRS)

    Testa, Massimo

    1990-01-01

    In the large quark mass limit, an argument which identifies the mass of the heavy-light pseudoscalar or scalar bound state with the renormalized mass of the heavy quark is given. The following equation is discussed: m(sub Q) = m(sub B), where m(sub Q) and m(sub B) are respectively the mass of the heavy quark and the mass of the pseudoscalar bound state.

  11. Mutagenicity of heavy metals

    SciTech Connect

    Wong, P.K.

    1988-04-01

    Certain heavy metals are required, as trace elements for normal cellular functions. However, heavy metals are toxic to cells once their levels exceed their low physiological values. The toxicity of heavy metals on microorganisms, and on animals has been well-documented. These interactions may induce the alteration of the primary as well as secondary structures of the DNA and result in mutation(s). The present communication reports the results in determining the mutagenicity and carcinogenicity of ten heavy metals commonly found in polluted areas by using the Salmonella/mammalian-microsome mutagenicity test.

  12. Heavy Precipitation Events in Lithuania

    NASA Astrophysics Data System (ADS)

    Bukantis, A.; Rimkus, E.; Kažys, J.

    2010-09-01

    ), the smallest in the Middle Lithuanian plain (45-50 mm and 60-70 mm accordingly). Seasonal distribution of heavy precipitation events differs in Lithuanian regions. In the western part due to impact of warm Baltic sea the highest recurrence of heavy precipitation events was observed during late summer and autumn, meanwhile in other parts of Lithuania such events were more common only for summer months. More than one third of heavy precipitation events were observed during zonal atmospheric circulation mode. Location of central part of cyclone over Lithuania is the most common synoptic situation during heavy precipitation. Under such conditions record high of daily precipitation amount was observed (103,8 mm in Telšiai). Annual precipitation amount will increase (up to 22%) in 21st century according CCLM outputs. Number of days with precipitation will rise (up to 5% until the end of 21st century). Especially significant changes will be observed in spring (up to 10%). Heavy precipitation recurrence will also increase in Lithuanian territory. Number of one day heavy precipitation cases will be mostly altered in the Žemaičiai Highlands and coastal lowlands (>30%). Larger changes in almost whole territory are predicted under A1B emission scenario and only in northern part changes will be greater according to B1 emission scenario. In western part changes will be most significant in autumn, while in the east Lithuania in winter. Daily and 3-days precipitation amount probability for 10-year and a 100-year return period will increase in western part of Lithuania according to A1B scenario. Meanwhile modelling based on B1 scenario predicts decrease of probability of precipitation amount in this area for both analyzed return periods. Other parts of Lithuania will experience similar but less significant changes to compare with observation period of 1971 2000. Aknowledgement.This work was performed within BSR Interreg IVB Project 'Climate Change: Impacts, Costs and Adaptation in

  13. Micron-Accurate Laser Fresnel-Diffraction Ranging System

    NASA Technical Reports Server (NTRS)

    Lehner, David; Campbell, Jonathan; Smith, Kelly; Sanders, Alvin; Allison, Stephen; Smaley, Larry

    2008-01-01

    Two versions of an optoelectronic system undergoing development are depicted. The system is expected to be capable of measuring a distance between 2 and 10 m with an error of no more than 1 micrometer. The system would be designed to exploit Fresnel diffraction of a laser beam. In particular, it would be designed to take advantage of the fact that a Fresnel diffraction pattern is ultrasensitive to distance. The two versions would differ in the following respects: In version 1, the focus of the telescope would be in the Fresnel region, and the telescope would have a small depth of focus. As a consequence, the Fresnel pattern would be imaged directly onto the photodetector array; in version 2, a multielement lens module would displace the Fresnel region from the vicinity of the pinhole to the vicinity of the optical receiver. As the distance to be measured varied, the location of the receiver relative to the displaced Fresnel-diffraction region would vary, thereby causing the Fresnel diffraction pattern on the focal plane to vary. The multielement lens module would also correct for aberrations. The processing of the digitized Fresnel diffraction pattern in the computer might be accelerated by using only parts of the pattern or even only one small part - the central pixel. As the distance from the pinhole increased, the central pixel would rapidly cycle between maximum and minimum light intensity. This in itself would not be sufficient to uniquely determine the distance. However, by varying the size of the pinhole or the wavelength of the laser, one could obtain a second cycle of variation of intensity that, in conjunction with the first cycle, could enable a unique determination of distance. Alternatively, for a single wavelength and a single pinhole size, it should suffice to consider the data from only two different key pixels in the Fresnel pattern.

  14. Quantum critical behavior in heavy electron materials

    PubMed Central

    Yang, Yi-feng; Pines, David

    2014-01-01

    Quantum critical behavior in heavy electron materials is typically brought about by changes in pressure or magnetic field. In this paper, we develop a simple unified model for the combined influence of pressure and magnetic field on the effectiveness of the hybridization that plays a central role in the two-fluid description of heavy electron emergence. We show that it leads to quantum critical and delocalization lines that accord well with those measured for CeCoIn5, yields a quantitative explanation of the field and pressure-induced changes in antiferromagnetic ordering and quantum critical behavior measured for YbRh2Si2, and provides a valuable framework for describing the role of magnetic fields in bringing about quantum critical behavior in other heavy electron materials. PMID:24912172

  15. 50 years of fiber diffraction.

    PubMed

    Holmes, Kenneth C

    2010-05-01

    In 1955 Ken Holmes started working on tobacco mosaic virus (TMV) as a research student with Rosalind Franklin at Birkbeck College, London. Afterward he spent 18months as a post doc with Don Caspar and Carolyn Cohen at the Children's Hospital, Boston where he continued the work on TMV and also showed that the core of the thick filament of byssus retractor muscle from mussels is made of two-stranded alpha-helical coiled-coils. Returning to England he joined Aaron Klug's group at the newly founded Laboratory of Molecular Biology in Cambridge. Besides continuing the TMV studies, which were aimed at calculating the three-dimensional density map of the virus, he collaborated with Pringle's group in Oxford to show that two conformation of the myosin cross-bridge could be identified in insect flight muscle. In 1968 he opened the biophysics department at the Max Planck Institute for Medical Research in Heidelberg, Germany. With Gerd Rosenbaum he initiated the use of synchrotron radiation as a source for X-ray diffraction. In his lab the TMV structure was pushed to 4A resolution and showed how the RNA binds to the protein. With his co-workers he solved the structure of g-actin as a crystalline complex and then solved the structure of the f-actin filament by orientating the g-actin structure so as to give the f-actin fiber diffraction pattern. He was also able to solve the structure of the complex of actin with tropomyosin from fiber diffraction. PMID:20079849

  16. Coherent Diffractive Imaging at LCLS

    NASA Astrophysics Data System (ADS)

    Schulz, Joachim

    2010-03-01

    Soft x-ray FEL light sources produce ultrafast x-ray pulses with outstanding high peak brilliance. This might enable the structure determination of proteins that cannot be crystallized. The deposited energy would destroy the molecules completely, but owing to the short pulses the destruction will ideally only happen after the termination of the pulse. In order to address the many challenges that we face in attempting molecular diffraction, we have carried out experiments in coherent diffraction from protein nanocrystals at the Linac Coherent Light Source (LCLS) at SLAC. The periodicity of these objects gives us much higher scattering signals than uncrystallized proteins would. The crystals are filtered to sizes less than 2 micron, and delivered to the pulsed X-ray beam in a liquid jet. The effects of pulse duration and fluence on the high-resolution structure of the crystals have been studied. Diffraction patterns are recorded at a repetition rate of 30 Hz with pnCCD detectors. This allows us to take 108,000 images per hour. With 2-mega-pixel-detectors this gives a data-rate of more than 400 GB per hour. The automated sorting and evaluation of hundreds of thousands images is another challenge of this kind of experiments. Preliminary results will be presented on our first LCLS experiments. This work was carried out as part of a collaboration, for which Henry Chapman is the spokesperson. The collaboration consists of CFEL DESY, Arizona State University, SLAC, Uppsala University, LLNL, The University of Melbourne, LBNL, the Max Planck Institute for Medical Research, and the Max Planck Advanced Study Group (ASG) at the CFEL. The experiments were carried out using the CAMP apparatus, which was designed and built by the Max Planck ASG at CFEL. The LCLS is operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.

  17. Crystallography: Resolution beyond the diffraction limit

    NASA Astrophysics Data System (ADS)

    Shen, Jian-Ren

    2016-02-01

    A method has been devised that extends the resolution of X-ray crystal structures beyond the diffraction limit. This might help to improve the visualization of structures of proteins that form 'poorly diffracting' crystals. See Letter p.202

  18. Final Report: Algorithms for Diffractive Microscopy

    SciTech Connect

    Elser, Veit

    2010-10-08

    The phenomenal coherence and brightness of x-ray free-electron laser light sources, such as the LCLS at SLAC, have the potential of revolutionizing the investigation of structure and dynamics in the nano-domain. However, this potential will go unrealized without a similar revolution in the way the data are analyzed. While it is true that the ambitious design parameters of the LCLS have been achieved, the prospects of realizing the most publicized goal of this instrument — the imaging of individual bio-particles — remains daunting. Even with 10{sup 12} photons per x-ray pulse, the feebleness of the scattering process represents a fundamental limit that no amount of engineering ingenuity can overcome. Large bio-molecules will scatter on the order of only 10{sup 3} photons per pulse into a detector with 106 pixels; the diffraction “images” will be virtually indistinguishable from noise. Averaging such noisy signals over many pulses is not possible because the particle orientation cannot be controlled. Each noisy laser snapshot is thus confounded by the unknown viewpoint of the particle. Given the heavy DOE investment in LCLS and the profound technical challenges facing single-particle imaging, the final two years of this project have concentrated on this effort. We are happy to report that we succeeded in developing an extremely efficient algorithm that can reconstruct the shapes of particles at even the extremes of noise expected in future LCLS experiments with single bio-particles. Since this is the most important outcome of this project, the major part of this report documents this accomplishment. The theoretical techniques that were developed for the single-particle imaging project have proved useful in other imaging problems that are described at the end of the report.

  19. A diffractive mechanism of focusing.

    PubMed

    Case, W B; Sadurni, E; Schleich, W P

    2012-12-01

    We examine the free time evolution of a rectangular one dimensional Schrödinger wave packet of constant phase during the early stage which in the paraxial wave approximation is identical to the diffraction of a scalar field from a single slit. Our analysis, based on numerics and the Cornu spiral reveals considerable intricate detail behavior in the density and phase of the wave. We also point out a concentration of the intensity that occurs on axis and propose a new measure of width that expresses this concentration. PMID:23262675

  20. Fiber optic diffraction grating maker

    DOEpatents

    Deason, Vance A.; Ward, Michael B.

    1991-01-01

    A compact and portable diffraction grating maker comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate.

  1. Fiber optic diffraction grating maker

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1991-05-21

    A compact and portable diffraction grating maker is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate. 4 figures.

  2. Nonlinear ptychographic coherent diffractive imaging.

    PubMed

    Odstrcil, M; Baksh, P; Gawith, C; Vrcelj, R; Frey, J G; Brocklesby, W S

    2016-09-01

    Ptychographic Coherent diffractive imaging (PCDI) is a significant advance in imaging allowing the measurement of the full electric field at a sample without use of any imaging optics. So far it has been confined solely to imaging of linear optical responses. In this paper we show that because of the coherence-preserving nature of nonlinear optical interactions, PCDI can be generalised to nonlinear optical imaging. We demonstrate second harmonic generation PCDI, directly revealing phase information about the nonlinear coefficients, and showing the general applicability of PCDI to nonlinear interactions. PMID:27607631

  3. Issues in Optical Diffraction Theory

    PubMed Central

    Mielenz, Klaus D.

    2009-01-01

    This paper focuses on unresolved or poorly documented issues pertaining to Fresnel’s scalar diffraction theory and its modifications. In Sec. 2 it is pointed out that all thermal sources used in practice are finite in size and errors can result from insufficient coherence of the optical field. A quarter-wave criterion is applied to show how such errors can be avoided by placing the source at a large distance from the aperture plane, and it is found that in many cases it may be necessary to use collimated light as on the source side of a Fraunhofer experiment. If these precautions are not taken the theory of partial coherence may have to be used for the computations. In Sec. 3 it is recalled that for near-zone computations the Kirchhoff or Rayleigh-Sommerfeld integrals are applicable, but fail to correctly describe the energy flux across the aperture plane because they are not continuously differentiable with respect to the assumed geometrical field on the source side. This is remedied by formulating an improved theory in which the field on either side of a semi-reflecting screen is expressed as the superposition of mutually incoherent components which propagate in the opposite directions of the incident and reflected light. These components are defined as linear combinations of the Rayleigh-Sommerfeld integrals, so that they are rigorous solutions of the wave equation as well as continuously differentiable in the aperture plane. Algorithms for using the new theory for computing the diffraction patterns of circular apertures and slits at arbitrary distances z from either side of the aperture (down to z = ± 0.0003 λ) are presented, and numerical examples of the results are given. These results show that the incident geometrical field is modulated by diffraction before it reaches the aperture plane while the reflected field is spilled into the dark space. At distances from the aperture which are large compared to the wavelength λ these field expressions are

  4. The early development of neutron diffraction: science in the wings of the Manhattan Project.

    PubMed

    Mason, T E; Gawne, T J; Nagler, S E; Nestor, M B; Carpenter, J M

    2013-01-01

    Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan Project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurement of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor. Subsequent work by Wollan and Clifford G. Shull, who joined Wollan's group at Oak Ridge in 1946, laid the foundations for widespread application of neutron diffraction as an important research tool. PMID:23250059

  5. Feasibility studies for high pressure neutron powder diffraction experiments

    SciTech Connect

    Von Dreele, R.B. ); Parise, J. )

    1990-01-01

    We recently performed two neutron powder diffraction experiments on very small samples on the High Intensity Powder Diffractometer (HIPD). These were done to determine the feasibility of performing in situ high pressure/high temperature neutron diffraction experiments on HIPD at pressures which would exceed the previous limit of {approximately}50 kbar achievable in a neutron diffraction experiment. The first experiment consisted of examining the product from a high pressure preparation done at Stony Brook. The sample, which had been prepared at 65 kbar and 1000{degree}C, consisted of a small platinum capsule filled with CaGeO{sub 3} perovskite. The weights of the capsule included 225 mg of platinum and 49 mg of the germanate. A diffraction experiment taking {approximately}8.6 hrs at a LANSCE proton beam current of {approximately}53 {mu}A gave peaks of good intensity from both Pt and CaGeO{sub 3}; we could begin to see them after only 20 min of beam time. The second experiment was to test the possibility of diffraction from a high pressure apparatus. We placed in the HIPD sample position the central assembly from a 100 kbar octahedral press. Four tungsten carbide anvils and a copper block previously pressed to 65 kbar were held in an aluminum frame. The sample consisted of a small bit of nickel foil (175 mg) placed in a 3 mm hole in the copper block. The active sample volume is defined by the gap between the anvils and the length of the sample. A small portion of the copper block is also seen in this arrangement. This is viewed at 90{degree} 2{Theta} through a similar gap between the anvils by 4 1/2 in. {times} 12 in. {sup 3}He counter tubes. This arrangement simulates the operating conditions of a high pressure run at 100 kbar and takes advantage of the fixed instrument geometry possible in time-of-flight neutron diffraction experiments.

  6. Heavy-electron materials

    SciTech Connect

    Fisk, Z.; Ott, H.R.; Smith, J.L.

    1986-01-01

    De Haas-van Alphen results demonstrated the existence of a Fermi surface at sufficiently low temperature and show that the entire Fermi surface involves heavy electrons. The phase transitions in their heavy-electron state are discussed. These are either magnetic or superconducting. 38 refs., 6 figs., 2 tabs. (WRF)

  7. Ultrafast electron diffraction from aligned molecules

    SciTech Connect

    Centurion, Martin

    2015-08-17

    The aim of this project was to record time-resolved electron diffraction patterns of aligned molecules and to reconstruct the 3D molecular structure. The molecules are aligned non-adiabatically using a femtosecond laser pulse. A femtosecond electron pulse then records a diffraction pattern while the molecules are aligned. The diffraction patterns are then be processed to obtain the molecular structure.

  8. Undergraduate Experiment with Fractal Diffraction Gratings

    ERIC Educational Resources Information Center

    Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

  9. Mutagenicity of heavy metals

    SciTech Connect

    Wong, P.K. )

    1988-05-01

    Certain heavy metals are required, as trace elements for normal cellular functions. However, heavy metals are toxic to cells once their levels exceed their low physiological values. The toxicity of heavy metals on microorganisms, on plants and on animals has been well-documented. These interactions may induce the alteration of the primary as well as secondary structures of the DNA and result in mutation(s). Though the rec assay with Bacillus subtilis and the reversion assay with Escherichia coli were used to assess the mutagenicity of some heavy metals, the present communication reports the results in determining the mutagenicity and carcinogenicity of ten heavy metals commonly found in polluted areas by using the Salmonella/mammalian-microsome mutagenicity test.

  10. Diffraction optics for terahertz waves

    NASA Astrophysics Data System (ADS)

    Wiltse, James C.

    2004-09-01

    Conventional lenses are important components for many terahertz applications, but ordinary lenses are very difficult to fabricate for short-focal lengths. Multi-level phase-corrected zoned lens antennas have been investigated with particular application at terahertz wavelengths. These zoned lenses (or diffractive optics) give better performance than ordinary lenses, and because of their planar construction are easier and cheaper to fabricate. The depths of cut needed for a grooved zone plate are quite small, even when materials with low dielectric constants are used. Zoned lenses have been built and tested at various frequencies from 100 GHz to 1.5 THz, with phase correction levels of half-wave, quarter-wave, or eighth-wavelength. The inherent losses in transparent materials increase monotonically over this frequency range. Typical low-loss materials include polystyrene, polyethylene, Teflon, polycarbonate, polystyrene foam, foamed polyethylene, low density polytetrafluoroethylene (PTFE), TPX, quartz, sapphire, and silicon. Low dielectric-constant materials are normally preferred to reduce reflection and attenuation losses. Techniques for cutting or milling the materials to small dimensions are important, because at 1.0 THz an eighth-wavelength correction for silicon is only 15 μm. Another characteristic of zoned diffraction optics is their frequency behavior. Previous investigations have considered their bandwidth dependence and quasi-periodic extended frequency response for a specified focal length. As frequency changes, the focal point moves along the axis of the zoned lens. An analysis is given to explain this effect.

  11. Nuclear stopping and energy deposition into the central rapidity region

    SciTech Connect

    Zingman, J.A.

    1987-08-03

    Nuclear stopping and energy deposition into the central rapidity region of ultrarelativistic heavy-ion collisions are studied through the application of a model incorporating hydrodynamic baryon flow coupled to a self-consistent field calculated in the flux tube model. Ultrarelativistic heavy ion collisions are modeled in which the nuclei have passed through each other and as a result are charged and heated.

  12. Polarized point diffraction interferometer for fringe stabilization

    NASA Astrophysics Data System (ADS)

    Kihm, Hagyong; Lee, Yun-Woo

    2010-08-01

    We propose a new point diffraction interferometer using a polarizer with a pinholed for qualitative optical analysis. Diffraction from a polarizer with a pinholed makes reference and measurement waves. Interference fringe between diffracted-undiffracted measurement wave and undiffracted-diffracted reference wave is stabilized by common-path configuration. We examined the pinhole size and divergence angle of the diffracted wave for test optics with various numerical aperture. Optical parts comprising the interferometer can be assembled into a small monolithic component and embedded into an imaging target for easy alignment. Optical systems evaluating imaging performances such as modulation transfer function would benefit in aligning target objects.

  13. Image contrast of diffraction-limited telescopes for circular incoherent sources of uniform radiance

    NASA Technical Reports Server (NTRS)

    Shackleford, W. L.

    1980-01-01

    A simple approximate formula is derived for the background intensity beyond the edge of the image of uniform incoherent circular light source relative to the irradiance near the center of the image. The analysis applies to diffraction-limited telescopes with or without central beam obscuration due to a secondary mirror. Scattering off optical surfaces is neglected. The analysis is expected to be most applicable to spaceborne IR telescopes, for which diffraction can be the major source of off-axis response.

  14. Diffraction gratings for optical sensing

    NASA Astrophysics Data System (ADS)

    Lu, Patrick P.

    The following document summarizes a journey through the world of diffraction gratings, covering topics such as their history, fabrication, metrology, and uses in some of the most precise scientific experiments ever proposed. Though diffraction gratings have long been used for spectroscopy and pulse compression, it was not until recently that researchers have explored their ability to split and recombine single-frequency CW laser sources for high-precision interferometry. Gravitational-wave detection, one of the most challenging sensing applications to date, is being investigated by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Laser Interferometer Space Antenna (LISA) projects. Future generations of LIGO and LISA detectors may incorporate gratings as key optical components. This thesis describes the ways gratings can improve interferometer performance by simplifying thermal management and discusses the essential challenges that must be overcome before they can be adopted. The use of gratings requires new interferometer geometries. We show cases where these can be implemented simply and compactly. Gravitational-wave interferometry imposes many requirements on grating components. Using improved metrology methods, we demonstrate that large dielectric gratings with uniformly high efficiency can be fabricated and validated. In particular, we measure the diffraction efficiency of two 20-cm-scale gratings over their entire apertures. The values taken from across their surfaces collectively had means and standard deviations of mu = 99.293% and sigma = 0.164%, and mu =99.084% and sigma =0.079%. We also present simplified models of thermal distortions in gratings, and show them to be in good agreement with measurements conducted by a wavefront sensor. Special focus is given to experimental demonstrations that have achieved highly precise measurements of translational and rotational motion, also known as displacement and angular sensing. For the former

  15. Fresnel diffraction of aperture with rough edge

    NASA Astrophysics Data System (ADS)

    Cui, Yuwei; Zhang, Wei; Wang, Junhong; Zhang, Meina; Teng, Shuyun

    2015-06-01

    The Fresnel diffraction of an aperture with a rough edge is studied in this paper. Circular and elliptical apertures with sinusoidal and random edges are chosen as examples to investigate the influence of the aperture edge on the diffraction. The numerical calculation results indicate intuitively the variations of the transverse and longitude diffraction intensity distributions with the edge parameters of the aperture. The data files of aperture models are obtained through the numerical calculations, and the aperture samples are obtained with the help of a liquid crystal light modulator (LCLM). Thus, the practical experiments of the diffractions of apertures with rough edges are carried out. The measured results are consistent with the calculated ones. The approximate analytic expressions of the diffraction by the modified aperture are deduced on the basis of the Fresnel diffraction theory and the statistic optics, and the reasonable explanations for the influence of edge parameters on the diffraction are given through the theoretical analysis.

  16. Diffractive X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald K.

    2010-01-01

    Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  17. Variable focus crystal diffraction lens

    SciTech Connect

    Smither, R.K.

    1988-11-01

    A new method has been developed to control the shape of the surface of a diffracting crystal that will allow it to function as a variable focus crystal diffraction lens, for focusing photon beams from a synchrotron source. The new method uses thermal gradients in the crystal to control the shape of the surface of the crystal in two dimensions and allows one to generate both spherical and ellipsoidal surface shapes. In this work the thermal gradient was generated by core drilling two sets of cooling channels in a silicon crystal so that cooling or heating fluids could be circulated through the crystal at two different levels. The first set of channels is close to the surface of the crystal where the photon beam strikes it. The second set of channels is equal distant from the back surface. If a concave surface is desired, the fluid in the channels just below the surface exposed to the beam is cooler than the fluid circulating through the channels near the back surface. If a convex surface is desired, then the cooling fluid in the upper channels near the surface exposed to the incident photon beam, is warmer than the fluid in the lower channels. The focal length of the crystal lens is varied by varying the thermal gradient in the crystal. This approach can also be applied to the first crystal in a high power synchrotron beam line to eliminate the bowing and other thermal distortions of the crystal caused by the high heat load. 6 refs., 8 figs., 3 tabs.

  18. Space charge effects in ultrafast electron diffraction and imaging

    SciTech Connect

    Tao Zhensheng; Zhang He; Duxbury, P. M.; Berz, Martin; Ruan, Chong-Yu

    2012-02-15

    Understanding space charge effects is central for the development of high-brightness ultrafast electron diffraction and microscopy techniques for imaging material transformation with atomic scale detail at the fs to ps timescales. We present methods and results for direct ultrafast photoelectron beam characterization employing a shadow projection imaging technique to investigate the generation of ultrafast, non-uniform, intense photoelectron pulses in a dc photo-gun geometry. Combined with N-particle simulations and an analytical Gaussian model, we elucidate three essential space-charge-led features: the pulse lengthening following a power-law scaling, the broadening of the initial energy distribution, and the virtual cathode threshold. The impacts of these space charge effects on the performance of the next generation high-brightness ultrafast electron diffraction and imaging systems are evaluated.

  19. Diffractive theorems for the wave equation with inverse square potentials

    NASA Astrophysics Data System (ADS)

    Qian, Randy Zhigang

    This dissertation investigates the phenomenon of diffraction resulting from the addition of an inverse square potential term to the wave operator. In particular, it explicitly establishes the existence of diffraction for the solution to the wave operator with an inverse square potential in 2-dimensional euclidean space and proves a propagation of smoothness result in two more general settings. Chapter 2 establishes diffraction in the fundamental solutions to the wave operator plus inverse square potential with a Dirac Delta initial condition in 2-dimensional euclidean space. Following methods as described by Cheeger and Taylor, we separate variables, apply spectral transforms to each variable, and employ contour deformation techniques to establish an explicit form for diffractive front in the fundamental solution. Chapter 3 proves a propagation of smoothness result for a related wave operator with potential, where instead of a constant, we put a smooth bounded function in the numerator of the potential. Microlocal energy estimates are used following the basic propagation methods of Duistermaat and Hormander, and employing the heavy refinements due to Melrose, Vasy, and Wunsch to handle propagation through the radial point at the origin. The potential term is estimated using Hardy's Inequality. Chapter 4 extends the propagation of smoothness result to conic manifolds with an inverse square potential concentrated at their boundary. We state a product decomposition theorem for the conic metric due to Melrose and Wunsch, then use the resulting coordinates to deploy our argument from Chapter 3. New terms with dependence on distance to the boundary arise, and we show how to bound them.

  20. Heavy-ion dosimetry

    SciTech Connect

    Schimmerling, W.

    1980-03-01

    This lecture deals with some of the more important physical characteristics of relativistic heavy ions and their measurement, with beam delivery and beam monitoring, and with conventional radiation dosimetry as used in the operation of the BEVALAC biomedical facility for high energy heavy ions (Lyman and Howard, 1977; BEVALAC, 1977). Even so, many fundamental aspects of the interaction of relativistic heavy ions with matter, including important atomic physics and radiation chemical considerations, are not discussed beyond the reminder that such additional understanding is required before an adequte perspective of the problem can be attained.

  1. Pre-equilibrium decay processes in energetic heavy ion reactions

    SciTech Connect

    Blann, M.

    1986-04-15

    The Boltzmann master equation (BME) is defined for application to precompound decay in heavy ion reactions in the 10 100 MeV/nucleon regime. Predicted neutron spectra are compared with measured results for central collisions of /sup 20/Ne and /sup 12/C with /sup 165/Ho target nuclei. Comparisons are made with subthreshold ..pi../sup 0/ yields in heavy ion reactions between 35 and 84 MeV/nucleon, and with the ..pi../sup 0/ spectra. The BME is found to be an excellent tool for investigating these experimentally observed aspects of non-equilibrium heavy ion reactions. 18 refs., 8 figs.

  2. Bragg's Law diffraction simulations for electron backscatter diffraction analysis.

    PubMed

    Kacher, Josh; Landon, Colin; Adams, Brent L; Fullwood, David

    2009-08-01

    In 2006, Angus Wilkinson introduced a cross-correlation-based electron backscatter diffraction (EBSD) texture analysis system capable of measuring lattice rotations and elastic strains to high resolution. A variation of the cross-correlation method is introduced using Bragg's Law-based simulated EBSD patterns as strain free reference patterns that facilitates the use of the cross-correlation method with polycrystalline materials. The lattice state is found by comparing simulated patterns to collected patterns at a number of regions on the pattern using the cross-correlation function and calculating the deformation from the measured shifts of each region. A new pattern can be simulated at the deformed state, and the process can be iterated a number of times to converge on the absolute lattice state. By analyzing an iteratively rotated single crystal silicon sample and recovering the rotation, this method is shown to have an angular resolution of approximately 0.04 degrees and an elastic strain resolution of approximately 7e-4. As an example of applications, elastic strain and curvature measurements are used to estimate the dislocation density in a single grain of a compressed polycrystalline Mg-based AZ91 alloy. PMID:19520512

  3. Central Italy

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Clouds and haze cover most of the Italian peninsula in this view of central Italy (41.5N, 14.0E) but the Bay of Naples region with Mt. Vesuvius and the island of Capri are clear. The Adriatic Sea in the background separates Italy from the cloud covered Balkans of eastern Europe and the Tyrrhenian Sea in the foreground lies between the Italian mainland and the off scene islands of Corsica and Sardinia. Several aircraft contrails can also be seen.

  4. Aerodynamics of Heavy Vehicles

    NASA Astrophysics Data System (ADS)

    Choi, Haecheon; Lee, Jungil; Park, Hyungmin

    2014-01-01

    We present an overview of the aerodynamics of heavy vehicles, such as tractor-trailers, high-speed trains, and buses. We introduce three-dimensional flow structures around simplified model vehicles and heavy vehicles and discuss the flow-control devices used for drag reduction. Finally, we suggest important unsteady flow structures to investigate for the enhancement of aerodynamic performance and future directions for experimental and numerical approaches.

  5. Ratios of heavy baryons to heavy mesons in relativistic nucleus-nucleus collisions

    SciTech Connect

    Oh, Yongseok; Ko, Che Ming; Lee, Su Houng; Yasui, Shigehiro

    2009-04-15

    Heavy baryon/meson ratios {lambda}{sub c}/D{sup 0} and {lambda}{sub b}/B{sup 0} in relativistic heavy ion collisions are studied in the quark coalescence model. For heavy baryons, we include production from coalescence of heavy quarks with free light quarks as well as with bounded light diquarks that might exist in the strongly coupled quark-gluon plasma produced in these collisions. Including the contribution from decays of heavy hadron resonances and also that due to fragmentation of heavy quarks that are left in the system after coalescence, the resulting {lambda}{sub c}/D{sup 0} and {lambda}{sub b}/B{sup 0} ratios in midrapidity (|y|{<=}0.5) from central Au+Au collisions at {radical}(s{sub NN})=200 GeV are about a factor of five and ten, respectively, larger than those given by the thermal model, and about a factor of ten and twelve, respectively, larger than corresponding ratios in the PYTHIA model for pp collisions. These ratios are reduced by a factor of about 1.6 if there are no diquarks in the quark-gluon plasma. The transverse momentum dependence of the heavy baryon/meson ratios is found to be sensitive to the heavy quark mass, with the {lambda}{sub b}/B{sup 0} ratio being much flatter than the {lambda}{sub c}/D{sup 0} ratio. The latter peaks at the transverse momentum p{sub T}{approx_equal}0.8 GeV but the peak shifts to p{sub T}{approx_equal}2 GeV in the absence of diquarks.

  6. Structural molecular biology: Recent results from neutron diffraction

    NASA Astrophysics Data System (ADS)

    Timmins, Peter A.

    1995-02-01

    Neutron diffraction is of importance in structural biology at several different levels of resolution. In most cases the unique possibility arising from deuterium labelling or contrast variation is of fundamental importance in providing information complementary to that which can be obtained from X-ray diffraction. At high resolution, neutron crystallography of proteins allows the location of hydrogen atoms in the molecule or of the hydration water, both of which may be central to biological activity. A major difficulty in this field has been the poor signal-to-noise ratio of the data arising not only from relatively low beam intensities and small crystals but, most importantly from the incoherent background due to hydrogen atoms in the sample. Modern methods of molecular biology now offer ways of producing fully deuterated proteins by cloning in bacteria grown on fully deuterated media. At a slightly lower resolution, there are a number of systems which may be ordered in one or two dimensions. This is the case in the purple membrane where neutron diffraction with deuterium labelling has complemented high resolution electron diffraction. Finally there is a class of very large macromolecular systems which can be crystallised and have been studied by X-ray diffraction but in which part of the structure is locally disordered and usually has insufficient contrast to be seen with X-rays. In this case the use of H 2O/D 2O contrast variation allows these components to be located. Examples of this are the nucleic acid in virus structures and detergent bound to membrane proteins.

  7. Process for removing heavy metal compounds from heavy crude oil

    DOEpatents

    Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

    1991-01-01

    A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

  8. Double diffraction dissociation at the Fermilab Tevatron collider.

    PubMed

    Affolder, T; Akimoto, H; Akopian, A; Albrow, M G; Amaral, P; Amidei, D; Anikeev, K; Antos, J; Apollinari, G; Arisawa, T; Asakawa, T; Ashmanskas, W; Azfar, F; Azzi-Bacchetta, P; Bacchetta, N; Bailey, M W; Bailey, S; de Barbaro, P; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Barone, M; Bauer, G; Bedeschi, F; Belforte, S; Bell, W H; Bellettini, G; Bellinger, J; Benjamin, D; Bensinger, J; Beretvas, A; Berge, J P; Berryhill, J; Bhatti, A; Binkley, M; Bisello, D; Bishai, M; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Blusk, S R; Bocci, A; Bodek, A; Bokhari, W; Bolla, G; Bonushkin, Y; Borras, K; Bortoletto, D; Boudreau, J; Brandl, A; van Den Brink, S; Bromberg, C; Brozovic, M; Bruner, N; Buckley-Geer, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Byon-Wagner, A; Byrum, K L; Cabrera, S; Calafiura, P; Campbell, M; Carithers, W; Carlson, J; Carlsmith, D; Caskey, W; Castro, A; Cauz, D; Cerri, A; Chan, A W; Chang, P S; Chang, P T; Chapman, J; Chen, C; Chen, Y C; Cheng, M T; Chertok, M; Chiarelli, G; Chirikov-Zorin, I; Chlachidze, G; Chlebana, F; Christofek, L; Chu, M L; Chung, Y S; Ciobanu, C I; Clark, A G; Connolly, A; Convery, M; Conway, J; Cordelli, M; Cranshaw, J; Cropp, R; Culbertson, R; Dagenhart, D; D'Auria, S; DeJongh, F; Dell'Agnello, S; Dell'Orso, M; Demortier, L; Deninno, M; Derwent, P F; Devlin, T; Dittmann, J R; Dominguez, A; Donati, S; Done, J; D'Onofrio, M; Dorigo, T; Eddy, N; Einsweiler, K; Elias, J E; Engels, E; Erbacher, R; Errede, D; Errede, S; Fan, Q; Feild, R G; Fernandez, J P; Ferretti, C; Field, R D; Fiori, I; Flaugher, B; Foster, G W; Franklin, M; Freeman, J; Friedman, J; Fukui, Y; Furic, I; Galeotti, S; Gallas, A; Gallinaro, M; Gao, T; Garcia-Sciveres, M; Garfinkel, A F; Gatti, P; Gay, C; Gerdes, D W; Giannetti, P; Glagolev, V; Glenzinski, D; Gold, M; Goldstein, J; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Green, C; Grim, G; Gris, P; Groer, L; Grosso-Pilcher, C; Guenther, M; Guillian, G; Guimaraes Da Costa, J; Haas, R M; Haber, C; Hahn, S R; Hall, C; Handa, T; Handler, R; Hao, W; Happacher, F; Hara, K; Hardman, A D; Harris, R M; Hartmann, F; Hatakeyama, K; Hauser, J; Heinrich, J; Heiss, A; Herndon, M; Hill, C; Hoffman, K D; Holck, C; Hollebeek, R; Holloway, L; Hughes, R; Huston, J; Huth, J; Ikeda, H; Incandela, J; Introzzi, G; Iwai, J; Iwata, Y; James, E; Jones, M; Joshi, U; Kambara, H; Kamon, T; Kaneko, T; Karr, K; Kasha, H; Kato, Y; Keaffaber, T A; Kelley, K; Kelly, M; Kennedy, R D; Kephart, R; Khazins, D; Kikuchi, T; Kilminster, B; Kim, B J; Kim, D H; Kim, H S; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kirby, M; Kirk, M; Kirsch, L; Klimenko, S; Koehn, P; Kondo, K; Konigsberg, J; Korn, A; Korytov, A; Kovacs, E; Kroll, J; Kruse, M; Kuhlmann, S E; Kurino, K; Kuwabara, T; Laasanen, A T; Lai, N; Lami, S; Lammel, S; Lancaster, J; Lancaster, M; Lander, R; Latino, G; LeCompte, T; Lee, A M; Lee, K; Leone, S; Lewis, J D; Lindgren, M; Liss, T M; Liu, J B; Liu, Y C; Litvintsev, D O; Lobban, O; Lockyer, N; Loken, J; Loreti, M; Lucchesi, D; Lukens, P; Lusin, S; Lyons, L; Lys, J; Madrak, R; Maeshima, K; Maksimovic, P; Malferrari, L; Mangano, M; Mariotti, M; Martignon, G; Martin, A; Matthews, J A; Mayer, J; Mazzanti, P; McFarland, K S; McIntyre, P; McKigney, E; Menguzzato, M; Menzione, A; Mesropian, C; Meyer, A; Miao, T; Miller, R; Miller, J S; Minato, H; Miscetti, S; Mishina, M; Mitselmakher, G; Moggi, N; Moore, E; Moore, R; Morita, Y; Moulik, T; Mulhearn, M; Mukherjee, A; Muller, T; Munar, A; Murat, P; Murgia, S; Nachtman, J; Nagaslaev, V; Nahn, S; Nakada, H; Nakano, I; Nelson, C; Nelson, T; Neu, C; Neuberger, D; Newman-Holmes, C; Ngan, C Y; Niu, H; Nodulman, L; Nomerotski, A; Oh, S H; Oh, Y D; Ohmoto, T; Ohsugi, T; Oishi, R; Okusawa, T; Olsen, J; Orejudos, W; Pagliarone, C; Palmonari, F; Paoletti, R; Papadimitriou, V; Partos, D; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pescara, L; Phillips, T J; Piacentino, G; Pitts, K T; Pompos, A; Pondrom, L; Pope, G; Popovic, M; Prokoshin, F; Proudfoot, J; Ptohos, F; Pukhov, O; Punzi, G; Rakitine, A; Reher, D; Reichold, A; Ribon, A; Riegler, W; Rimondi, F; Ristori, L; Riveline, M; Robertson, W J; Robinson, A; Rodrigo, T; Rolli, S; Rosenson, L; Roser, R; Rossin, R; Roy, A; Ruiz, A; Safonov, A; St Denis, R; Sakumoto, W K; Saltzberg, D; Sanchez, C; Sansoni, A; Santi, L; Sato, H; Savard, P; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Scodellaro, L; Scott, A; Scribano, A; Segler, S; Seidel, S; Seiya, Y; Semenov, A; Semeria, F; Shah, T; Shapiro, M D; Shepard, P F; Shibayama, T; Shimojima, M; Shochet, M; Sidoti, A; Siegrist, J; Sill, A; Sinervo, P; Singh, P; Slaughter, A J; Sliwa, K; Smith, C; Snider, F D; Solodsky, A; Spalding, J; Speer, T; Sphicas, P; Spinella, F; Spiropulu, M; Spiegel, L; Steele, J; Stefanini, A; Strologas, J; Strumia, F; Stuart, D; Sumorok, K; Suzuki, T; Takano, T; Takashima, R; Takikawa, K; Tamburello, P; Tanaka, M

    2001-10-01

    We present results from a measurement of double diffraction dissociation in pp collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width Deltaeta(0)>3 (overlapping eta = 0) is found to be 4.43+/-0.02(stat)+/-1.18(syst) mb [ 3.42+/-0.01(stat)+/-1.09(syst) mb] at square root of (s) = 1800[630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization. PMID:11580642

  9. Anomalous Diffraction in Crystallographic Phase Evaluation

    PubMed Central

    Hendrickson, Wayne A.

    2014-01-01

    X-ray diffraction patterns from crystals of biological macromolecules contain sufficient information to define atomic structures, but atomic positions are inextricable without having electron-density images. Diffraction measurements provide amplitudes, but the computation of electron density also requires phases for the diffracted waves. The resonance phenomenon known as anomalous scattering offers a powerful solution to this phase problem. Exploiting scattering resonances from diverse elements, the methods of multiwavelength anomalous diffraction (MAD) and single-wavelength anomalous diffraction (SAD) now predominate for de novo determinations of atomic-level biological structures. This review describes the physical underpinnings of anomalous diffraction methods, the evolution of these methods to their current maturity, the elements, procedures and instrumentation used for effective implementation, and the realm of applications. PMID:24726017

  10. Hard diffraction with dynamic gap survival

    NASA Astrophysics Data System (ADS)

    Rasmussen, Christine O.; Sjöstrand, Torbjörn

    2016-02-01

    We present a new framework for the modelling of hard diffraction in pp and poverline{p} collisions. It starts from the the approach pioneered by Ingelman and Schlein, wherein the single diffractive cross section is factorized into a Pomeron flux and a Pomeron PDF. To this it adds a dynamically calculated rapidity gap survival factor, derived from the modelling of multiparton interactions. This factor is not relevant for diffraction in ep collisions, giving non-universality between HERA and Tevatron diffractive event rates. The model has been implemented in P ythia 8 and provides a complete description of the hadronic state associated with any hard single diffractive process. Comparisons with poverline{p} and pp data reveal improvement in the description of single diffractive events.

  11. Optimizing Crystal Volume for Neutron Diffraction

    NASA Technical Reports Server (NTRS)

    Snell, Edward H.; vanderWoerd, Mark; Damon, Michael; Judge, Russell, A.; Myles, Dean; Meilleur, F.

    2006-01-01

    Neutron diffraction is uniquely sensitive to hydrogen positions and protonation state. In that context structural information from neutron data is complementary to that provided through X-ray diffraction. However, there are practical obstacles to overcome in fully exploiting the potential of neutron diffraction, Le. low flux and weak scattering. Several approaches are available to overcome these obstacles and we have investigated the simplest: increasing the diffracting volume of the crystals. Volume is a quantifiable metric that is well suited for experiment design and optimization techniques. By using response surface methods we have optimized xylose isomerase crystal volume, enabling neutron diffraction while we determined the crystallization parameters with the minimum of experiments. Our results suggest a systematic means of enabling neutron diffraction studies for a larger number of samples that require information on hydrogen position and/or protonation state.

  12. Twenty years of diffraction at the Tevatron

    SciTech Connect

    Goulianos, K.; /Rockefeller U.

    2005-10-01

    Results on diffractive particle interactions from the Fermilab Tevatron {bar p}p collider are placed in perspective through a QCD inspired phenomenological approach, which exploits scaling and factorization properties observed in data. The results discussed are those obtained by the CDF Collaboration from a comprehensive set of single, double, and multigap soft and hard diffraction processes studied during the twenty year period since 1985, when the CDF diffractive program was proposed and the first Blois Workshop was held.

  13. Diffraction gratings used as identifying markers

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1991-03-26

    A finely detailed diffraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the diffraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating. 7 figures.

  14. Aircraft noise propagation. [sound diffraction by wings

    NASA Technical Reports Server (NTRS)

    Hadden, W. J.; Pierce, A. D.

    1978-01-01

    Sound diffraction experiments conducted at NASA Langley Research Center to study the acoustical implications of the engine over wing configuration (noise-shielding by wing) and to provide a data base for assessing various theoretical approaches to the problem of aircraft noise reduction are described. Topics explored include the theory of sound diffraction around screens and wedges; the scattering of spherical waves by rectangular patches; plane wave diffraction by a wedge with finite impedence; and the effects of ambient flow and distribution sources.

  15. Convex Diffraction Grating Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Chrisp, Michael P. (Inventor)

    1999-01-01

    A 1:1 Offner mirror system for imaging off-axis objects is modified by replacing a concave spherical primary mirror that is concentric with a convex secondary mirror with two concave spherical mirrors M1 and M2 of the same or different radii positioned with their respective distances d1 and d2 from a concentric convex spherical diffraction grating having its grooves parallel to the entrance slit of the spectrometer which replaces the convex secondary mirror. By adjusting their distances d1 and d2 and their respective angles of reflection alpha and beta, defined as the respective angles between their incident and reflected rays, all aberrations are corrected without the need to increase the spectrometer size for a given entrance slit size to reduce astigmatism, thus allowing the imaging spectrometer volume to be less for a given application than would be possible with conventional imaging spectrometers and still give excellent spatial and spectral imaging of the slit image spectra over the focal plane.

  16. Sub-wavelength diffractive optics

    SciTech Connect

    Warren, M.E.; Wendt, J.R.; Vawter, G.A.

    1998-03-01

    This report represents the completion of a three-year Laboratory-Directed Research and Development (LDRD) program to investigate sub-wavelength surface relief structures fabricated by direct-write e-beam technology as unique and very high-efficiency optical elements. A semiconductor layer with sub-wavelength sized etched openings or features can be considered as a layer with an effective index of refraction determined by the fraction of the surface filled with semiconductor relative to the fraction filled with air or other material. Such as a layer can be used to implement planar gradient-index lenses on a surface. Additionally, the nanometer-scale surface structures have diffractive properties that allow the direct manipulation of polarization and altering of the reflective properties of surfaces. With this technology a single direct-write mask and etch can be used to integrate a wide variety of optical functions into a device surface with high efficiencies; allowing for example, direct integration of polarizing optics into the surface with high efficiencies; allowing for example, direct integration of polarizing optics into the surfaces of devices, forming anti-reflection surfaces or fabricating high-efficiency, high-numerical aperture lenses, including integration inside vertical semiconductor laser cavities.

  17. Large aperture diffractive space telescope

    DOEpatents

    Hyde, Roderick A.

    2001-01-01

    A large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass "aiming" at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.

  18. Neutron diffraction facilities at the high flux reactor, Petten

    NASA Astrophysics Data System (ADS)

    Ohms, C.; Youtsos, A. G.; Bontenbal, A.; Mulder, F. M.

    2000-03-01

    The High Flux Reactor in Petten is equipped with twelve beam tubes for the extraction of thermal neutrons for applications in materials and medical science. Beam tubes HB4 and HB5 are equipped with diffractometers for residual stress and powder investigations. Recently at HB4 the Large Component Neutron Diffraction Facility has been installed. It is a unique facility with respect to its capability of handling heavy components up to 1000 kg in residual stress testing. Its basic features are described and the first applications on thick piping welds are shown. The diffractometer at HB5 can be set up for powder and stress measurements. Recent applications include temperature dependent measurements on phase transitions in intermetallic compounds and on Li ion energy storage materials.

  19. Preparation and X-ray diffraction studies of curium hydrides

    NASA Astrophysics Data System (ADS)

    Gibson, J. K.; Haire, R. G.

    1985-10-01

    Curium hydrides were prepared by reaction of curium-248 metal with hydrogen and characterized by X-ray powder diffraction. Several of the syntheses resulted in a hexagonal compound with average lattice parameters of a0 = 0.3769(8) nm and c0 = 0.6732(12) nm. These products are considered to be CmH 3-δ by analogy with the behavior of lanthanide-hydrogen and lighter actinide-hydrogen systems. Face-centered cubic products with an average lattice parameter of a0 = 0.5322(4) nm were obtained from other curium hydride preparations. This parameter is slightly smaller than that reported previously for cubic curium dihydride, CmH 2+ x (B. M. Bansal and D. Damien, Inorg. Nucl. Chem. Lett., 6, 603, 1970). The present results established a continuation of typical heavy trivalent lanthanide-like behavior of the transuranium actinide-hydrogen systems through curium.

  20. Diffractively corrected counter-rotating Risley prisms.

    PubMed

    Nie, Xin; Yang, Hongfang; Xue, Changxi

    2015-12-10

    Using the vector refraction equation and the vector diffraction equation, we obtain the expressions of the direction cosines of the refractive rays for the two wedge prisms, and the direction cosines of the diffractive rays for two wedge grisms, in which diffractive gratings were etched into the prism faces to correct the chromatic aberrations. A mathematical model between the two vector equations is proposed to compare the difference angle chromatic aberrations when the Risley prisms/grisms are rotating at different angles. We conclude that the use of diffractively corrected prisms offers a new method to correct chromatic aberrations in Risley prisms. PMID:26836873

  1. Broadband diffractive lens or imaging element

    DOEpatents

    Ceglio, N.M.; Hawryluk, A.M.; London, R.A.; Seppala, L.G.

    1993-10-26

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed. Thin film embodiments are described. 21 figures.

  2. Diffraction by m-bonacci gratings

    NASA Astrophysics Data System (ADS)

    Monsoriu, Juan A.; Giménez, Marcos H.; Furlan, Walter D.; Barreiro, Juan C.; Saavedra, Genaro

    2015-11-01

    We present a simple diffraction experiment with m-bonacci gratings as a new interesting generalization of the Fibonacci ones. Diffraction by these non-conventional structures is proposed as a motivational strategy to introduce students to basic research activities. The Fraunhofer diffraction patterns are obtained with the standard equipment present in most undergraduate physics labs and are compared with those obtained with regular periodic gratings. We show that m-bonacci gratings produce discrete Fraunhofer patterns characterized by a set of diffraction peaks which positions are related to the concept of a generalized golden mean. A very good agreement is obtained between experimental and numerical results and the students’ feedback is discussed.

  3. Electron Diffraction Using Transmission Electron Microscopy

    PubMed Central

    Bendersky, Leonid A.; Gayle, Frank W.

    2001-01-01

    Electron diffraction via the transmission electron microscope is a powerful method for characterizing the structure of materials, including perfect crystals and defect structures. The advantages of electron diffraction over other methods, e.g., x-ray or neutron, arise from the extremely short wavelength (≈2 pm), the strong atomic scattering, and the ability to examine tiny volumes of matter (≈10 nm3). The NIST Materials Science and Engineering Laboratory has a history of discovery and characterization of new structures through electron diffraction, alone or in combination with other diffraction methods. This paper provides a survey of some of this work enabled through electron microscopy.

  4. Broadband diffractive lens or imaging element

    DOEpatents

    Ceglio, Natale M.; Hawryluk, Andrew M.; London, Richard A.; Seppala, Lynn G.

    1993-01-01

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed. Thin film embodiments are described.

  5. Broadband diffractive lens or imaging element

    DOEpatents

    Ceglio, Natale M.; Hawryluk, Andrew M.; London, Richard A.; Seppala, Lynn G.

    1991-01-01

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed.

  6. Defining Electron Backscatter Diffraction Resolution

    SciTech Connect

    El-Dasher, B S; Rollett, A D

    2005-02-07

    Automated electron backscatter diffraction (EBSD) mapping systems have existed for more than 10 years [1,2], and due to their versatility in characterizing multiple aspects of microstructure, they have become an important tool in microscale crystallographic studies. Their increasingly widespread use however raises questions about their accuracy in both determining crystallographic orientations, as well as ensuring that the orientation information is spatially correct. The issue of orientation accuracy (as defined by angular resolution) has been addressed previously [3-5]. While the resolution of EBSD systems is typically quoted to be on the order of 1{sup o}, it has been shown that by increasing the pattern quality via acquisition parameter adjustment, the angular resolution can be improved to sub-degree levels. Ultimately, the resolution is dependent on how it is identified. In some cases it can be identified as the orientation relative to a known absolute, in others as the misorientation between nearest neighbor points in a scan. Naturally, the resulting values can be significantly different. Therefore, a consistent and universal definition of resolution that can be applied to characterize any EBSD system is necessary, and is the focus of the current study. In this work, a Phillips (FEI) XL-40 FEGSEM coupled to a TexSEM Laboratories OIM system was used. The pattern capturing hardware consisted of both a 512 by 512 pixel SIT CCD camera and a 1300 by 1030 pixel Peltier cooled CCD camera. Automated scans of various sizes, each consisting of 2500 points, were performed on a commercial-grade single crystal silicon wafer used for angular resolution measurements. To adequately quantify angular resolution for all possible EBSD applications we define two angular values. The first is {omega}{sub center}, the mean of the misorientation angle distribution between all scan points and the scan point coincident to the calibration source (typically the scan center). The {omega

  7. Characterization of high energy Xe ion irradiation effects in single crystal molybdenum with depth-resolved synchrotron microbeam diffraction

    NASA Astrophysics Data System (ADS)

    Yun, Di; Miao, Yinbin; Xu, Ruqing; Mei, Zhigang; Mo, Kun; Mohamed, Walid; Ye, Bei; Pellin, Michael J.; Yacout, Abdellatif M.

    2016-04-01

    Microbeam X-ray diffraction experiments were conducted at beam line 34-ID of the Advanced Photon Source (APS) on fission fragment energy Xe heavy ion irradiated single crystal Molybdenum (Mo). Lattice strain measurements were obtained with a depth resolution of 0.7 μm, which is critical in resolving the peculiar heterogeneity of irradiation damage associated with heavy ion irradiation. Q-space diffraction peak shift measurements were correlated with lattice strain induced by the ion irradiations. Transmission electron microscopy (TEM) characterizations were performed on the as-irradiated materials as well. Nanometer sized Xe bubble microstructures were observed via TEM. Molecular Dynamics (MD) simulations were performed to help interpret the lattice strain measurement results from the experiment. This study showed that the irradiation effects by fission fragment energy Xe ion irradiations can be collaboratively understood with the depth resolved X-ray diffraction and TEM measurements under the assistance of MD simulations.

  8. Calculation of the diffraction efficiency on concave gratings based on Fresnel-Kirchhoff's diffraction formula.

    PubMed

    Huang, Yuanshen; Li, Ting; Xu, Banglian; Hong, Ruijin; Tao, Chunxian; Ling, Jinzhong; Li, Baicheng; Zhang, Dawei; Ni, Zhengji; Zhuang, Songlin

    2013-02-10

    Fraunhofer diffraction formula cannot be applied to calculate the diffraction wave energy distribution of concave gratings like plane gratings because their grooves are distributed on a concave spherical surface. In this paper, a method based on the Kirchhoff diffraction theory is proposed to calculate the diffraction efficiency on concave gratings by considering the curvature of the whole concave spherical surface. According to this approach, each groove surface is divided into several limited small planes, on which the Kirchhoff diffraction field distribution is calculated, and then the diffraction field of whole concave grating can be obtained by superimposition. Formulas to calculate the diffraction efficiency of Rowland-type and flat-field concave gratings are deduced from practical applications. Experimental results showed strong agreement with theoretical computations. With the proposed method, light energy can be optimized to the expected diffraction wave range while implementing aberration-corrected design of concave gratings, particularly for the concave blazed gratings. PMID:23400074

  9. Characterization of the diffraction properties of quantum-dot-array diffraction grating

    NASA Astrophysics Data System (ADS)

    Wang, Chuanke; Kuang, Longyu; Wang, Zhebin; Liu, Shenye; Ding, Yongkun; Cao, Leifeng; Foerster, Eckhart; Wang, Deqiang; Xie, Changqing; Ye, Tianchun

    2007-05-01

    A new dispersive element named as quantum-dot-array diffraction grating [L. F. Cao, China patent No. 200410081499 (August 10, 2004)] for visible light has been developed and characterized experimentally. A large number of quantum dots distributed on a substrate as sinusoidal function can be used to diffract x rays without higher-order diffraction. The experimental patterns show that the higher-order diffractions which inevitably exist in the spectrum recorded using traditional diffraction gratings can be eliminated effectively by this newly designed element. It indicates that quantum-dot-array diffraction grating could be an attractive alternative of presently used diffraction grating in soft x-ray spectroscopy application to get rid of the higher-order diffraction distortions.

  10. Characterization of the diffraction properties of quantum-dot-array diffraction grating

    SciTech Connect

    Wang Chuanke; Kuang Longyu; Wang Zhebin; Liu Shenye; Ding Yongkun; Cao Leifeng; Foerster, Eckhart; Wang Deqiang; Xie Changqing; Ye Tianchun

    2007-05-15

    A new dispersive element named as quantum-dot-array diffraction grating [L. F. Cao, China patent No. 200410081499 (August 10, 2004)] for visible light has been developed and characterized experimentally. A large number of quantum dots distributed on a substrate as sinusoidal function can be used to diffract x rays without higher-order diffraction. The experimental patterns show that the higher-order diffractions which inevitably exist in the spectrum recorded using traditional diffraction gratings can be eliminated effectively by this newly designed element. It indicates that quantum-dot-array diffraction grating could be an attractive alternative of presently used diffraction grating in soft x-ray spectroscopy application to get rid of the higher-order diffraction distortions.

  11. Breaking resolution limits in ultrafast electron diffraction and microscopy

    PubMed Central

    Baum, Peter; Zewail, Ahmed H.

    2006-01-01

    Ultrafast electron microscopy and diffraction are powerful techniques for the study of the time-resolved structures of molecules, materials, and biological systems. Central to these approaches is the use of ultrafast coherent electron packets. The electron pulses typically have an energy of 30 keV for diffraction and 100–200 keV for microscopy, corresponding to speeds of 33–70% of the speed of light. Although the spatial resolution can reach the atomic scale, the temporal resolution is limited by the pulse width and by the difference in group velocities of electrons and the light used to initiate the dynamical change. In this contribution, we introduce the concept of tilted optical pulses into diffraction and imaging techniques and demonstrate the methodology experimentally. These advances allow us to reach limits of time resolution down to regimes of a few femtoseconds and, possibly, attoseconds. With tilted pulses, every part of the sample is excited at precisely the same time as when the electrons arrive at the specimen. Here, this approach is demonstrated for the most unfavorable case of ultrafast crystallography. We also present a method for measuring the duration of electron packets by autocorrelating electron pulses in free space and without streaking, and we discuss the potential of tilting the electron pulses themselves for applications in domains involving nuclear and electron motions. PMID:17056711

  12. Design examples of diffraction-limited catadioptric objectives

    NASA Astrophysics Data System (ADS)

    Gallert, Frank

    1996-08-01

    The paper relates to different inventions, comprising three diffraction-limited catadioptric designs. All the systems use only spherical shaped surfaces and are designed from one kind of optical material only. In the examples the glass BK7 from the Schott-catalogue was used. The first example gives a three element design reaching equal performance as a Schmidt camera but with only 25 percent of its length. Additionally the field is flat and conveniently located behind the system. The second example is designed to reduce the central obstruction. It's somewhat based on the principle of the Houghton-camera. For a f-number 4 system with 1000 millimeters focal length it gives outstanding image quality at a 5 degree's field--even capable for diffraction-limited visual use. For reduced f-number 5,6 the image is diffraction-limited at the whole field. In terms of color correction it outperforms every Schmidt-Cassegrain or apochromatic triplet of even arbitrarily more reduced light gathering power. The third example is the equivalent for the so-called Wynne corrector triplet that corrects the aberrations of a parabolical mirror. But the invented corrector corrects additionally the spherical aberration of a spherical mirror. The corrector is able to correct all third order aberrations without introducing longitudinal and lateral color.

  13. CMS results on exclusive and diffractive production

    SciTech Connect

    Alves, Gilvan A.

    2015-04-10

    We present recent CMS measurements of diffractive and exclusive processes, using data collected at 7 TeV at the LHC. Measurements of soft single- and double-diffractive cross sections are presented, as well as measurements of photon-induced processes including studies of exclusive WW production via photon-photon exchange.

  14. White-Light Diffraction with a CD

    ERIC Educational Resources Information Center

    Ivanov, Dragia Trifonov; Nikolaev, Stefan

    2010-01-01

    Various wave optics experiments can be carried out using an ordinary compact disc. The CD is suitable for use as a diffraction grating. For instance, a standard CD (700 MB) has 625 lines/mm. In this article, the authors describe two white-light diffraction demonstrations for a large audience, realizable using a CD (as reflection or transmission…

  15. Liquid-Crystal Point-Diffraction Interferometer

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.

    1996-01-01

    Liquid-crystal point-diffraction interferometer (LCPDI) invented to combine flexible control of liquid-crystal phase-shifts with robustness of point-diffraction interferometers. Produces interferograms indicative of shapes of wavefronts of laser beams having passed through or reflected from objects of interest. Interferograms combined in computers to produce phase maps describing wavefronts.

  16. Structure refinement from precession electron diffraction data.

    PubMed

    Palatinus, Lukáš; Jacob, Damien; Cuvillier, Priscille; Klementová, Mariana; Sinkler, Wharton; Marks, Laurence D

    2013-03-01

    Electron diffraction is a unique tool for analysing the crystal structures of very small crystals. In particular, precession electron diffraction has been shown to be a useful method for ab initio structure solution. In this work it is demonstrated that precession electron diffraction data can also be successfully used for structure refinement, if the dynamical theory of diffraction is used for the calculation of diffracted intensities. The method is demonstrated on data from three materials - silicon, orthopyroxene (Mg,Fe)(2)Si(2)O(6) and gallium-indium tin oxide (Ga,In)(4)Sn(2)O(10). In particular, it is shown that atomic occupancies of mixed crystallographic sites can be refined to an accuracy approaching X-ray or neutron diffraction methods. In comparison with conventional electron diffraction data, the refinement against precession diffraction data yields significantly lower figures of merit, higher accuracy of refined parameters, much broader radii of convergence, especially for the thickness and orientation of the sample, and significantly reduced correlations between the structure parameters. The full dynamical refinement is compared with refinement using kinematical and two-beam approximations, and is shown to be superior to the latter two. PMID:23403968

  17. Diffraction experiments with infrared remote controls

    NASA Astrophysics Data System (ADS)

    Kuhn, Jochen; Vogt, Patrik

    2012-02-01

    In this paper we describe an experiment in which radiation emitted by an infrared remote control is passed through a diffraction grating. An image of the diffraction pattern is captured using a cell phone camera and then used to determine the wavelength of the radiation.

  18. RENORM predictions of diffraction at LHC confirmed

    SciTech Connect

    Goulianos, Konstantin

    2015-04-10

    The RENORM model predictions of diffractive, total, and total-inelastic cross sections at the LHC are confirmed by recent measurements. The predictions of several other available models are discussed, highlighting their differences from RENORM, mainly arising from the way rapidity gap formation, low- and high-mass diffraction, unitarization, and hadronization are implemented.

  19. Inquiry with Laser Printer Diffraction Gratings

    ERIC Educational Resources Information Center

    Van Hook, Stephen J.

    2007-01-01

    The pages of "The Physics Teacher" have featured several clever designs for homemade diffraction gratings using a variety of materials--cloth, lithographic film, wire, compact discs, parts of aerosol spray cans, and pseudoliquids and pseudosolids. A different and inexpensive method I use to make low-resolution diffraction gratings takes advantage…

  20. Intensity Measurements in a Fresnel Diffraction Pattern

    ERIC Educational Resources Information Center

    Boyer, R.; Fortin, E.

    1972-01-01

    Describes an undergraduate optics laboratory experiment to verify the law of intensity in the Fesnel diffraction of a thin wire. A gas laser as light source and a photocell as detector scan the diffraction pattern. The agreement with the theoretical pattern is remarkably good. (Author/TS)

  1. Studies of heavy hadron physics

    SciTech Connect

    Guo Xinheng

    2011-12-14

    In the diquark picture, we establish Bethe-Salpeter equations for ground states of heavy baryons containing one heavy quark and two heavy quarks in the heavy quark limit, respectively. The Bethe-Salpeter equations for both heavy and light diquarks are also established. Assuming kernels to consist of a scalar confinement term and a one-gluon-exchange term we solve Bethe-Salpeter wave functions numerically in the covariant instantaneous approximation and give some applications including semileptonic and nonleptonic decay widths of heavy baryons, the average kinetic energy of the heavy quark in {Lambda}{sub Q}, {Sigma}{sub Q}{sup (*)}{yields}{Lambda}{sub Q}+{pi} decay widths, and heavy quark distribution functions. We also study possible molecular heavy bound states in the Bethe-Salpeter approach. Proof of QCD factorization for {Lambda}{sub b}{yields}{Lambda}{sub c}{pi} is presented in the framework of QCD factorization.

  2. The early development of neutron diffraction: Science in the wings of the Manhattan Project

    SciTech Connect

    Mason, Thom; Gawne, Timothy J; Nagler, Stephen E; Nestor, Margaret Boone {Bonnie}; Carpenter, John M

    2012-01-01

    Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurements of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst, and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor.

  3. Heavy quark production in photon-Pomeron interactions at high energies

    SciTech Connect

    Machado, M. M.; Goncalves, V. P.

    2013-03-25

    The diffractive heavy quark cross sections are estimated considering photon-Pomeron interactions in hadron - hadron at RHIC, Tevatron, and CERN LHC energies. We assume the validity of the hard diffractive factorization and calculate the charm and bottom total cross sections and rapidity distributions using the diffractive parton distribution functions of the Pomeron obtained by the H1 Collaboration at DESY-HERA. Such processes are sensitive to the gluon content of the Pomeron at high energies and are a good place to constrain the behavior of this distribution. We also compare our predictions with those obtained using the dipole model, and verify that these processes are a good test of the different mechanisms for heavy quarks diffractive production at hadron colliders.

  4. Relativistic Heavy Ion Collider

    SciTech Connect

    Willen, E.H.

    1986-01-01

    The Relativistic Heavy Ion Collider (RHIC) is a proposed research facility at Brookhaven National Laboratory to study the collision of beams of heavy ions, up to gold in mass and at beam energies up to 100 GeV/nucleon. The physics to be explored by this collider is an overlap between the traditional disciplines of nuclear physics and high energy physics and is a continuation of the planned program of light and heavy ion physics at BNL. The machine is to be constructed in the now-empty tunnel built for the former CBA project. Various other facilities to support the collider are either in place or under construction at BNL. The collider itself, including the magnets, is in an advanced state of design, and a construction start is anticipated in the next several years.

  5. The effect of machining error on the diffraction efficiency of refraction and diffractive optical element

    NASA Astrophysics Data System (ADS)

    Gao, Long; Xue, Changxi; Yang, Hongfang; Nie, Xin

    2014-08-01

    According to the expression of the phase delay and diffraction efficiency of the diffractive optical elements(DOEs), the expression of diffraction efficiency of refraction and diffractive optical element with the tilt and decenter error in fabrication process was presented in this paper. Analysis results show, in the wavelength band of 501nm-554nm, the cycle of 500μm, the center wavelength of 521nm, when the tilt angleα increases form 0° to9.8° , the diffraction efficiency is above 99%; when the tilt angleα increases form 9.8° to 29.7° , diffraction efficiency is above 92.5%; when the tilt angleα is above 29.7° , the diffraction efficiency declines rapidly, diffraction efficiency is 0 when the tilt angleα is above 58° . When the decenter Δ increases form 0nm to 21.6μm,the diffraction efficiency is above 98%; when the decenter Δ increases form 21.6nm to 63.3μm, the diffraction efficiency is above 90%; when the decenter Δ is above 63.3μm, the diffraction efficiency declines rapidly, diffraction efficiency is 0 when the he decenter Δ is above 241.7μm. To sum up the results of analysis,mathematical analysis model of the relationship between the decenter and tilt error of diffractive optical element in processing and the diffraction efficiency can be used to guide the design of the refraction and diffractive hybrid optical system comprising the diffractive optical element.

  6. Nonlinear diffraction in orientation-patterned semiconductors.

    PubMed

    Karpinski, Pawel; Chen, Xin; Shvedov, Vladlen; Hnatovsky, Cyril; Grisard, Arnaud; Lallier, Eric; Luther-Davies, Barry; Krolikowski, Wieslaw; Sheng, Yan

    2015-06-01

    This work represents experimental demonstration of nonlinear diffraction in an orientation-patterned semiconducting material. By employing a new transverse geometry of interaction, three types of second-order nonlinear diffraction have been identified according to different configurations of quasi-phase matching conditions. Specifically, nonlinear Čerenkov diffraction is defined by the longitudinal quasi-phase matching condition, nonlinear Raman-Nath diffraction satisfies only the transverse quasi-phase matching condition, and nonlinear Bragg diffraction fulfils the full vectorial quasi-phase matching conditions. The study extends the concept of transverse nonlinear parametric interaction toward infrared frequency conversion in semiconductors. It also offers an effective nondestructive method to visualise and diagnose variations of second-order nonlinear coefficients inside semiconductors. PMID:26072847

  7. Diffraction in time: An exactly solvable model

    NASA Astrophysics Data System (ADS)

    Goussev, Arseni

    2014-03-01

    In optics, diffraction is typically portrayed as deflection of light incident upon an obstacle with sharp boundaries, that can not be accounted for by reflection or refraction. Interestingly, quantum mechanics allows for an additional, intrinsically time-dependent manifestation of the phenomenon: Owing to the dispersive nature of quantum matter waves, sudden changes in boundary conditions may cause the particle wave function to develop interference fringes akin to those in stationary (optical) diffraction problems. This phenomenon, pioneered in 1952 by Moshinsky [Phys. Rev. 88, 625 (1952)] and presently referred to as ``diffraction in time,'' is at the heart of a vibrant area of experimental and theoretical research concerned with quantum transients. In my talk, I will introduce a new versatile exactly-solvable model of diffraction in time. The model describes dynamics of a quantum particle in the presence of an absorbing time-dependent barrier, and enables a quantitative description of diffraction and interference patterns in a large variety of setups.

  8. Fraunhofer diffraction by arbitrary-shaped obstacles.

    PubMed

    Malinka, Aleksey V; Zege, Eleonora P

    2009-08-01

    We consider Fraunhofer diffraction by an ensemble of large arbitrary-shaped screens that are randomly oriented in the plane of a wavefront and have edges of arbitrary shape. It is shown that far outside the main diffraction peak the differential scattering cross section behaves asymptotically as theta(-3), where theta is the diffraction angle. Moreover, the differential scattering cross section depends only on the length of the contours bordering the screens and does not depend on the shape of the obstacles. As both strictly forward and total diffraction cross sections are specified by obstacle area only, the differential cross section of size-distributed obstacles is expected to be nearly independent of obstacle shape over the entire region of the diffraction angles. PMID:19649110

  9. [Galactic heavy charged particles damaging effect on biological structures].

    PubMed

    Grigor'ev, A I; Krasavin, E A; Ostrovskiĭ, M A

    2013-03-01

    A concept of the radiation risk of the manned interplanetary flights is proposed and substantiated. Heavy charged particles that are a component of the galactic cosmic rays (GCR) have a high damaging effect on the biological structures as great amount of energy is deposited in heavy particle tracks. The high biological effectiveness of heavy ions is observed in their action on cell genetic structures and the whole organism, including the brain structures. The hippocampus is the part of the central nervous system that is the most sensitive to radiation--first of all, to heavy charged particles. Irradiation of animals with accelerated iron ions at doses corresponding to the real fluxes of GCR heavy nuclei, to which Mars mission crews can be exposed, leads to marked behavioral function disorders in the post-irradiation period. To evaluate the radiation risk for the interplanetary flight crews, the concept of successful mission accomplishment is introduced. In these conditions, the central nervous system structures can be the critical target of GCR heavy nuclei. Their damage can modify the higher integrative functions of the brain and cause disorders in the crew members' operator performances. PMID:23789432

  10. Heavy quark production by a quasi-classical color field in proton-nucleus collisions

    NASA Astrophysics Data System (ADS)

    Tuchin, Kirill

    2004-07-01

    We calculate the inclusive heavy quark production cross section for proton-nucleus collisions at high energies. We perform calculation in a quasi-classical approximation (McLerran-Venugopalan model) neglecting all low-x evolution effects. The derived expression for the differential cross section can be applied for studying the heavy quark production in the central rapidity region at RHIC.

  11. (Relativistic heavy ion research)

    SciTech Connect

    Not Available

    1990-01-01

    At Brookhaven National Laboratory, participation in the E802 Experiment, which is the first major heavy-ion experiment at the BNL-AGS, was the main focus of the group during the past four years. The emphases of the E802 experiment were on (a) accurate particle identification and measurements of spectra over a wide kinematical domain (5{degree} < {theta}{sub LAB} < 55{degree}, p < 20 GeV/c); and (b) measurements of small-angle two-particle correlations, with event characterization tools: multiplicity array, forward and large-angle calorimeters. This experiment and other heavy ion collision experiments are discussed in this report.

  12. Future of Electron Scattering and Diffraction

    SciTech Connect

    Hall, Ernest; Stemmer, Susanne; Zheng, Haimei; Zhu, Yimei; Maracas, George

    2014-02-25

    spectroscopy with high spatial resolution without damaging their structure. The strong interaction of electrons with matter allows high-energy electron pulses to gather structural information before a sample is damaged. Electron ScatteringImaging, diffraction, and spectroscopy are the fundamental capabilities of electron-scattering instruments. The DOE BES-funded TEAM (Transmission Electron Aberration-corrected Microscope) project achieved unprecedented sub-atomic spatial resolution in imaging through aberration-corrected transmission electron microscopy. To further advance electron scattering techniques that directly enable groundbreaking science, instrumentation must advance beyond traditional two-dimensional imaging. Advances in temporal resolution, recording the full phase and energy spaces, and improved spatial resolution constitute a new frontier in electron microscopy, and will directly address the BES Grand Challenges, such as to “control the emergent properties that arise from the complex correlations of atomic and electronic constituents” and the “hidden states” “very far away from equilibrium”. Ultrafast methods, such as the pump-probe approach, enable pathways toward understanding, and ultimately controlling, the chemical dynamics of molecular systems and the evolution of complexity in mesoscale and nanoscale systems. Central to understanding how to synthesize and exploit functional materials is having the ability to apply external stimuli (such as heat, light, a reactive flux, and an electrical bias) and to observe the resulting dynamic process in situ and in operando, and under the appropriate environment (e.g., not limited to UHV conditions). To enable revolutionary advances in electron scattering and science, the participants of the workshop recommended three major new instrumental developments: A. Atomic-Resolution Multi-Dimensional Transmission Electron Microscope: This instrument would provide quantitative information over the entire real space

  13. Diffraction and Imaging Study of Imperfections of Protein Crystals with Coherent X-rays

    NASA Technical Reports Server (NTRS)

    Hu, Z. W.; Thomas, B. R.; Chernov, A. A.; Chu, Y. S.; Lai, B.

    2004-01-01

    High angular-resolution x-ray diffraction and phase contrast x-ray imaging were combined to study defects and perfection of protein crystals. Imperfections including line defects, inclusions and other microdefects were observed in the diffraction images of a uniformly grown lysozyme crystal. The observed line defects carry distinct dislocation features running approximately along the <110> growth front and have been found to originate mostly in a central growth area and occasionally in outer growth regions. Slow dehydration led to the broadening of a fairly symmetric 4 4 0 rocking curve by a factor of approximately 2.6, which was primarily attributed to the dehydration-induced microscopic effects that are clearly shown in diffraction images. X-ray imaging and diffraction characterization of the quality of apoferritin crystals will also be discussed in the presentation.

  14. Tolerance analysis of multilayer diffractive optics based on polychromatic integral diffraction efficiency.

    PubMed

    Mao, Shan; Cui, Qingfeng; Piao, Mingxu

    2015-11-10

    Multilayer diffractive optical elements (MLDOEs) can achieve high diffraction efficiency for broadband wavelength. Polychromatic integral diffraction efficiency (PIDE) is the key concern for evaluating diffraction efficiency over the waveband. The modulation transfer function of a hybrid refractive-diffractive optical system is directly affected by the PIDE. The relationship between PIDE and continuous manufacturing errors for microstructure heights and periodic widths of MLDOEs is studied theoretically in this paper, and an example of MLDOEs is discussed in the visible waveband. The analysis results can be used for manufacturing error control in microstructure heights and periodic widths. PMID:26560782

  15. Transmittance analysis of diffraction phase grating.

    PubMed

    Jing, Xufeng; Jin, Yunxia

    2011-03-20

    In order to accurately analyze and design the transmittance characteristic of a diffraction phase grating, the validity of both the scalar diffraction theory and the effective medium theory is quantitatively evaluated by the comparison of diffraction efficiencies predicted from both simplified theories to exact results calculated by the rigorous vector electromagnetic theory. The effect of surface profile parameters, including the normalized period, the normalized depth, and the fill factor for the precision of the simplified methods is determined at normal incidence. It is found that, in general, when the normalized period is more than four wavelengths of the incident light, the scalar diffraction theory is useful to estimate the transmittance of the phase grating. When the fill factor approaches 0.5, the error of the scalar method is minimized, and the scalar theory is accurate even at the grating period of two wavelengths. The transmittance characteristic as a function of the normalized period is strongly influenced by the grating duty cycle, but the diffraction performance on the normalized depth is independent of the fill factor of the grating. Additionally, the effective medium theory is accurate for evaluating the diffraction efficiency within an error of less than around 1% when no higher-order diffraction waves appear and only the zero-order waves exist. The precision of the effective medium theory for calculating transmittance properties as a function of the normalized period, the normalized groove depth, and the polarization state of incident light is insensitive to the fill factor of the phase grating. PMID:21460923

  16. Chromatic confocal microscopy using staircase diffractive surface.

    PubMed

    Rayer, Mathieu; Mansfield, Daniel

    2014-08-10

    A chromatic confocal microscope (CCM) is a high-dynamic-range noncontact distance measurement sensor; it is based on a hyperchromatic lens. The vast majority of commercial CCMs use refractive-based chromatic dispersion to chromatically code the optical axis. This approach significantly limits the range of applications and performance of the CCM. In order to be a suitable alternative to a laser triangulation gauge and laser encoder, the performance of the CCM must be improved. In this paper, it is shown how hybrid aspheric diffractive (HAD) lenses can bring the CCM to its full potential by increasing the dynamic range by a factor of 2 and the resolution by a factor of 5 while passively athermizing and increasing the light throughput efficiency of the optical head [M. Rayer, U.S. patent 1122052.2 (2011)]. The only commercially suitable manufacturing process is single-point diamond turning. However, the optical power carried by the diffractive side of a hybrid aspheric diffractive lens is limited by the manufacturing process. A theoretical study of manufacturing losses has revealed that the HAD configuration with the highest diffraction efficiency is for a staircase diffractive surface (SDS). SDS lenses have the potential to reduce light losses associated with manufacturing limits by a factor of 5 without increasing surface roughness, allowing scalar diffraction-limited optical design with a diffractive element. PMID:25320920

  17. Detection of heavy metal by paper-based microfluidics.

    PubMed

    Lin, Yang; Gritsenko, Dmitry; Feng, Shaolong; Teh, Yi Chen; Lu, Xiaonan; Xu, Jie

    2016-09-15

    Heavy metal pollution has shown great threat to the environment and public health worldwide. Current methods for the detection of heavy metals require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Various microfluidic paper-based analytical devices have been developed recently as simple, cheap and disposable alternatives to conventional ones for on-site detection of heavy metals. In this review, we first summarize current development of paper-based analytical devices and discuss the selection of paper substrates, methods of device fabrication, and relevant theories in these devices. We then compare and categorize recent reports on detection of heavy metals using paper-based microfluidic devices on the basis of various detection mechanisms, such as colorimetric, fluorescent, and electrochemical methods. To finalize, the future development and trend in this field are discussed. PMID:27131999

  18. STAR heavy flavor tracker

    NASA Astrophysics Data System (ADS)

    Qiu, Hao

    2014-11-01

    Hadrons containing heavy quarks are a clean probe of the early dynamic evolution of the dense and hot medium created in high-energy nuclear collisions. To explore heavy quark production at RHIC, the Heavy Flavor Tracker (HFT) for the STAR experiment was built and installed in time for RHIC Run 14. The HFT consists of four layers of silicon detectors. The two outermost layers are silicon strip detectors and the two innermost layers are made from state-of-the-art ultra-thin CMOS Monolithic Active Pixel Sensors (MAPS). This is the first application of a CMOS MAPS detector in a collider experiment. The use of thin pixel sensors plus the use of carbon fiber supporting material limits the material budget to be only 0.4% radiation length per pixel detector layer, enabling the reconstruction of low pT heavy flavor hadrons. The status and performance of the HFT in the RHIC 200 GeV Au + Au run in 2014 are reported. Very good detector efficiency, hit residuals and track resolution (DCAs) were observed in the cosmic ray data and in the Au + Au data.

  19. Resonances in heavy systems

    SciTech Connect

    Betts, R.R.

    1983-01-01

    The experimental situation for the study of resonances in heavy-ion collisions is reviewed, with emphasis on the heaviest systems. New data are presented which show some of the systematics of this phenomenon. The narrow resonance structures are established as a feature of the nuclear structure of the composite system rather than a purely entrance channel effect.

  20. Heavy Chain Diseases

    MedlinePlus

    ... cells often prevents proper absorption of nutrients from food (malabsorption), resulting in severe diarrhea and weight loss. A rare form that affects the respiratory tract also exists. Blood tests are done when alpha heavy chain disease is suspected. Serum protein electrophoresis, measurement of ...

  1. Detection of heavy Higgs

    SciTech Connect

    Gordon, H.A.

    1984-01-01

    The prospects for detecting heavy Higgs are discussed. In particular a general procedure is developed which includes studying first the characteristics of producing the signal, estimating the most important background, simulating both types of events via Monte Carlo techniques in an appropriate detector and concluding with the prospects for detection. 20 references.

  2. Heavy Vehicle Systems

    SciTech Connect

    Sid Diamond; Richard Wares; Jules Routbort

    2000-04-11

    Heavy Vehicle (HV) systems are a necessary component of achieving OHVT goals. Elements are in place for a far-ranging program: short, intermediate, and long-term. Solicitation will bring industrial input and support. Future funding trend is positive, outlook for HV systems is good.

  3. Heavy Flavor Dynamics in Relativistic Heavy-ion Collisions

    NASA Astrophysics Data System (ADS)

    Cao, Shanshan

    Heavy flavor hadrons serve as valuable probes of the transport properties of the quark-gluon plasma (QGP) created in relativistic heavy-ion collisions. In this dissertation, we introduce a comprehensive framework that describes the full-time evolution of heavy flavor in heavy-ion collisions, including its initial production, in-medium evolution inside the QGP matter, hadronization process from heavy quarks to their respective mesonic bound states and the subsequent interactions between heavy mesons and the hadron gas. The in-medium energy loss of heavy quarks is studied within the framework of a Langevin equation coupled to hydrodynamic models that simulate the space-time evolution of the hot and dense QGP matter. We improve the classical Langevin approach such that, apart from quasi-elastic scatterings between heavy quarks and the medium background, radiative energy loss is incorporated as well by treating gluon radiation as a recoil force term. The subsequent hadronization of emitted heavy quarks is simulated via a hybrid fragmentation plus recombination model. The propagation of produced heavy mesons in the hadronic phase is described using the ultra-relativistic quantum molecular dynamics (UrQMD) model. Our calculation shows that while collisional energy loss dominates the heavy quark motion inside the QGP in the low transverse momentum (p T) regime, contributions from gluon radiation are found to be significant at high pT. The recombination mechanism is important for the heavy flavor meson production at intermediate energies. The hadronic final state interactions further enhance the suppression and the collective flow of heavy mesons we observe. Within our newly developed framework, we present numerical results for the nuclear modification and the elliptic flow of D mesons, which are consistent with measurements at both the CERN Large Hadron Collider (LHC) and the BNL Relativistic Heavy-Ion Collider (RHIC); predictions for B mesons are also provided. In

  4. Heavy quarks and lattice QCD

    SciTech Connect

    Andreas S. Kronfeld

    2003-11-05

    This paper is a review of heavy quarks in lattice gauge theory, focusing on methodology. It includes a status report on some of the calculations that are relevant to heavy-quark spectroscopy and to flavor physics.

  5. Heavy quark physics in CMS

    NASA Astrophysics Data System (ADS)

    Fedi, G.; CMS Collaboration

    2016-07-01

    The most recent results which concern the heavy quark hadrons done in the CMS experiment are reported. The searching area spans over the heavy quark spectroscopy, production cross sections, beauty meson decay properties, rare decays, and CP violation.

  6. Diffraction enhanced x-ray imaging

    SciTech Connect

    Thomlinson, W.; Zhong, Z.; Chapman, D.; Johnston, R.E.; Sayers, D.

    1997-09-01

    Diffraction enhanced imaging (DEI) is a new x-ray radiographic imaging modality using synchrotron x-rays which produces images of thick absorbing objects that are almost completely free of scatter. They show dramatically improved contrast over standard imaging applied to the same phantoms. The contrast is based not only on attenuation but also the refraction and diffraction properties of the sample. The diffraction component and the apparent absorption component (absorption plus extinction contrast) can each be determined independently. This imaging method may improve the image quality for medical applications such as mammography.

  7. 3D printed diffractive terahertz lenses.

    PubMed

    Furlan, Walter D; Ferrando, Vicente; Monsoriu, Juan A; Zagrajek, Przemysław; Czerwińska, Elżbieta; Szustakowski, Mieczysław

    2016-04-15

    A 3D printer was used to realize custom-made diffractive THz lenses. After testing several materials, phase binary lenses with periodic and aperiodic radial profiles were designed and constructed in polyamide material to work at 0.625 THz. The nonconventional focusing properties of such lenses were assessed by computing and measuring their axial point spread function (PSF). Our results demonstrate that inexpensive 3D printed THz diffractive lenses can be reliably used in focusing and imaging THz systems. Diffractive THz lenses with unprecedented features, such as extended depth of focus or bifocalization, have been demonstrated. PMID:27082335

  8. New diffractive results from the Tevatron

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2005-05-01

    Experimental results in diffractive processes are summarized and a few notable characteristics described in terms of Quantum Chromodynamics. Exclusive dijet production is used to establish a benchmark for future experiments in the quest for diffractive Higgs production at the Large Hadron Collider. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Stringent upper limits on the exclusive dijet production cross section are presented. The quark/gluon composition of dijet final states is used to provide additional hints on exclusive dijet production.

  9. A scattering approach to sea wave diffraction

    NASA Astrophysics Data System (ADS)

    Corradini, M. L.; Garbuglia, M.; Maponi, P.; Ruggeri, M.

    2016-06-01

    This paper intends to show a model for the diffraction of sea waves approaching an OWC device, which converts the sea waves motion into mechanical energy and then electrical energy. This is a preliminary study to the optimisation of the device, in fact the computation of sea waves diffraction around the device allows the estimation of the sea waves energy which enters into the device. The computation of the diffraction phenomenon is the result of a sea waves scattering problem, solved with an integral equation method.

  10. Strain Determination Using Electron Backscatter Diffraction

    SciTech Connect

    Krause, M.; Graff, A.; Altmann, F.

    2010-11-24

    In the present paper we demonstrate the use of electron backscatter diffraction (EBSD) for high resolution elastic strain determination. Here, we focus on analysis methods based on determination of small shifts in EBSD pattern with respect to a reference pattern using cross-correlation algorithms. Additionally we highlight the excellent spatial and depth resolution of EBSD and introduce the use of simulated diffraction patterns based on dynamical diffraction theory for sensitivity estimation. Moreover the potential of EBSD for strain analysis of strained thin films with particular emphasis on appropriate target preparation which respect to occurring lattice defects is demonstrated.

  11. Theory of hard diffraction and rapidity gaps

    SciTech Connect

    Del Duca, V.

    1996-02-01

    In this talk we review the models describing the hard diffractive production of jets or more generally high-mass states in presence of rapidity gaps in hadron-hadron and lepton-hadron collisions. By rapidity gaps we mean regions on the lego plot in (pseudo)-rapidity and azimuthal angle where no hadrons are produced, between the jet(s) and an elastically scattered hadron (single hard diffraction) or between two jets (double hard diffraction). {copyright} {ital 1996 American Institute of Physics.}

  12. Leaching Properties of Naturally Occurring Heavy Metals from Soils

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Hoshino, M.; Yoshikawa, M.; Hara, J.; Sugita, H.

    2014-12-01

    The major threats to human health from heavy metals are associated with exposure to arsenic, lead, cadmium, chromium, mercury, as well as some other elements. The effects of such heavy metals on human health have been extensively studied and reviewed by international organizations such as WHO. Due to their toxicity, heavy metal contaminations have been regulated by national environmental standards in many countries, and/or laws such as the Soil Contamination Countermeasures Act in Japan. Leaching of naturally occurring heavy metals from the soils, especially those around abandoned metal mines into surrounding water systems, either groundwater or surface water systems, is one of the major pathways of exposure. Therefore, understanding the leaching properties of toxic heavy metals from naturally polluted soils is of fundamentally importance for effectively managing abandoned metal mines, excavated rocks discharged from infrastructure constructions such as tunneling, and/or selecting a pertinent countermeasure against pollution when it is necessary. In this study, soil samples taken from the surroundings of abandoned metal mines in different regions in Japan were collected and analyzed. The samples contained multiple heavy metals such as lead, arsenic and chromium. Standard leaching test and sequential leaching test considering different forms of contaminants, such as trivalent and pentavalent arsenics, and trivalent and hexavalent chromiums, together with standard test for evaluating total concentration, X-ray Fluorescence Analysis (XRF), X-ray diffraction analysis (XRD) and Cation Exchange Capacity (CEC) tests were performed. In addition, sequential leaching tests were performed to evaluate long-term leaching properties of lead from representative samples. This presentation introduces the details of the above experimental study, discusses the relationships among leaching properties and chemical and mineral compositions, indicates the difficulties associated with

  13. Examining Factors Associated with Heavy Episodic Drinking Among College Undergraduates.

    PubMed

    Scholly, Kristen; Katz, Alan R; Kehl, Lisa

    2014-04-26

    Heavy episodic drinking among college students is a serious health concern. The purpose of this study was to identify factors associated with heavy episodic drinking behaviors amongst a predominately Asian undergraduate college student population in the United States. A survey measuring alcohol use behaviors was completed by a random sample of 18-24 year old undergraduates during April, 2011. A multivariate logistic regression analysis was conducted to determine factors associated with students' heavy episodic drinking behavior. Independent factors associated with heavy episodic drinking included living on campus, ethnicity, perceived drinking behavior among peers, and a belief that alcohol is a central part of one's social life. Heavy episodic drinking was also associated with poor academic performance. Campus-wide educational strategies to reduce heavy episodic drinking among college undergraduates should incorporate accurate information regarding alcohol use norms to correct students' perceived over estimation of their peers alcohol consumption rates and the under estimation of students protective alcohol use behaviors. These efforts should focus in on-campus residence halls where a higher occurrence of heavy episodic drinking is often found. PMID:26973931

  14. On the Numerical Study of Heavy Rainfall in Taiwan

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Chen, Ching-Sen; Chen, Yi-Leng; Jou, Ben Jong-Dao; Lin, Pay-Liam; Starr, David OC. (Technical Monitor)

    2001-01-01

    Heavy rainfall events are frequently observed over the western side of the CMR (central mountain range), which runs through Taiwan in a north-south orientation, in a southwesterly flow regime and over the northeastern side of the CMR in a northeasterly flow regime. Previous studies have revealed the mechanisms by which the heavy rainfall events are formed. Some of them have examined characteristics of the heavy rainfall via numerical simulations. In this paper, some of the previous numerical studies on heavy rainfall events around Taiwan during the Mei-Yu season (May and June), summer (non-typhoon cases) and autumn will be reviewed. Associated mechanisms proposed from observational studies will be reviewed first, and then characteristics of numerically simulated heavy rainfall events will be presented. The formation mechanisms of heavy rainfall from simulated results and from observational analysis are then compared and discussed. Based on these previous modeling studies, we will also discuss what are the major observations and modeling processes which will be needed for understanding the heavy precipitation in the future.

  15. Search for Heavy Pointlike Dirac Monopoles

    NASA Astrophysics Data System (ADS)

    Abbott, B.; Abolins, M.; Acharya, B. S.; Adam, I.; Adams, D. L.; Adams, M.; Ahn, S.; Aihara, H.; Alves, G. A.; Amos, N.; Anderson, E. W.; Astur, R.; Baarmand, M. M.; Babukhadia, L.; Baden, A.; Balamurali, V.; Balderston, J.; Baldin, B.; Banerjee, S.; Bantly, J.; Barberis, E.; Bartlett, J. F.; Belyaev, A.; Beri, S. B.; Bertram, I.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Bhattacharjee, M.; Biswas, N.; Blazey, G.; Blessing, S.; Bloom, P.; Boehnlein, A.; Bojko, N. I.; Borcherding, F.; Boswell, C.; Brandt, A.; Brock, R.; Bross, A.; Buchholz, D.; Burtovoi, V. S.; Butler, J. M.; Carvalho, W.; Casey, D.; Casilum, Z.; Castilla-Valdez, H.; Chakraborty, D.; Chang, S.-M.; Chekulaev, S. V.; Chen, L.-P.; Chen, W.; Choi, S.; Chopra, S.; Choudhary, B. C.; Christenson, J. H.; Chung, M.; Claes, D.; Clark, A. R.; Cobau, W. G.; Cochran, J.; Coney, L.; Cooper, W. E.; Cretsinger, C.; Cullen-Vidal, D.; Cummings, M. A.; Cutts, D.; Dahl, O. I.; Davis, K.; de, K.; del Signore, K.; Demarteau, M.; Denisov, D.; Denisov, S. P.; Diehl, H. T.; Diesburg, M.; di Loreto, G.; Draper, P.; Ducros, Y.; Dudko, L. V.; Dugad, S. R.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Engelmann, R.; Eno, S.; Eppley, G.; Ermolov, P.; Eroshin, O. V.; Evdokimov, V. N.; Fahland, T.; Fatyga, M. K.; Feher, S.; Fein, D.; Ferbel, T.; Finocchiaro, G.; Fisk, H. E.; Fisyak, Y.; Flattum, E.; Forden, G. E.; Fortner, M.; Frame, K. C.; Fuess, S.; Gallas, E.; Galyaev, A. N.; Gartung, P.; Gavrilov, V.; Geld, T. L.; Genik, R. J.; Genser, K.; Gerber, C. E.; Gershtein, Y.; Gibbard, B.; Glenn, S.; Gobbi, B.; Goldschmidt, A.; Gómez, B.; Gómez, G.; Goncharov, P. I.; González Solís, J. L.; Gordon, H.; Goss, L. T.; Gounder, K.; Goussiou, A.; Graf, N.; Grannis, P. D.; Green, D. R.; Greenlee, H.; Grinstein, S.; Grudberg, P.; Grünendahl, S.; Guglielmo, G.; Guida, J. A.; Guida, J. M.; Gupta, A.; Gurzhiev, S. N.; Gutierrez, G.; Gutierrez, P.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hahn, K. S.; Hall, R. E.; Hanlet, P.; Hansen, S.; Hauptman, J. M.; Hedin, D.; Heinson, A. P.; Heintz, U.; Hernández-Montoya, R.; Heuring, T.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoftun, J. S.; Hsieh, F.; Hu, Ting; Hu, Tong; Huehn, T.; Ito, A. S.; James, E.; Jaques, J.; Jerger, S. A.; Jesik, R.; Jiang, J. Z.-Y.; Joffe-Minor, T.; Johns, K.; Johnson, M.; Jonckheere, A.; Jones, M.; Jöstlein, H.; Jun, S. Y.; Jung, C. K.; Kahn, S.; Kalbfleisch, G.; Kang, J. S.; Karmanov, D.; Karmgard, D.; Kehoe, R.; Kelly, M. L.; Kim, C. L.; Kim, S. K.; Klima, B.; Klopfenstein, C.; Kohli, J. M.; Koltick, D.; Kostritskiy, A. V.; Kotcher, J.; Kotwal, A. V.; Kourlas, J.; Kozelov, A. V.; Kozlovsky, E. A.; Krane, J.; Krishnaswamy, M. R.; Krzywdzinski, S.; Kuleshov, S.; Kunori, S.; Landry, F.; Landsberg, G.; Lauer, B.; Leflat, A.; Li, H.; Li, J.; Li-Demarteau, Q. Z.; Lima, J. G.; Lincoln, D.; Linn, S. L.; Linnemann, J.; Lipton, R.; Liu, Y. C.; Lobkowicz, F.; Loken, S. C.; Lökös, S.; Lueking, L.; Lyon, A. L.; Maciel, A. K.; Madaras, R. J.; Madden, R.; Magaña-Mendoza, L.; Manankov, V.; Mani, S.; Mao, H. S.; Markeloff, R.; Marshall, T.; Martin, M. I.; Mauritz, K. M.; May, B.; Mayorov, A. A.; McCarthy, R.; McDonald, J.; McKibben, T.; McKinley, J.; McMahon, T.; Melanson, H. L.; Merkin, M.; Merritt, K. W.; Miettinen, H.; Mincer, A.; Mishra, C. S.; Mokhov, N.; Mondal, N. K.; Montgomery, H. E.; Mooney, P.; da Motta, H.; Murphy, C.; Nang, F.; Narain, M.; Narasimham, V. S.; Narayanan, A.; Neal, H. A.; Negret, J. P.; Nemethy, P.; Norman, D.; Oesch, L.; Oguri, V.; Oliveira, E.; Oltman, E.; Oshima, N.; Owen, D.; Padley, P.; Para, A.; Park, Y. M.; Partridge, R.; Parua, N.; Paterno, M.; Pawlik, B.; Perkins, J.; Peters, M.; Piegaia, R.; Piekarz, H.; Pischalnikov, Y.; Pope, B. G.; Prosper, H. B.; Protopopescu, S.; Qian, J.; Quintas, P. Z.; Raja, R.; Rajagopalan, S.; Ramirez, O.; Rasmussen, L.; Reucroft, S.; Rijssenbeek, M.; Rockwell, T.; Roco, M.; Rubinov, P.; Ruchti, R.; Rutherfoord, J.; Sánchez-Hernández, A.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Schellman, H.; Sculli, J.; Shabalina, E.; Shaffer, C.; Shankar, H. C.; Shivpuri, R. K.; Shupe, M.; Singh, H.; Singh, J. B.; Sirotenko, V.; Smart, W.; Smith, E.; Smith, R. P.; Snihur, R.; Snow, G. R.; Snow, J.; Snyder, S.; Solomon, J.; Sosebee, M.; Sotnikova, N.; Souza, M.; Spadafora, A. L.; Steinbrück, G.; Stephens, R. W.; Stevenson, M. L.; Stewart, D.; Stichelbaut, F.; Stoker, D.; Stolin, V.; Stoyanova, D. A.; Strauss, M.; Streets, K.; Strovink, M.; Sznajder, A.; Tamburello, P.; Tarazi, J.; Tartaglia, M.; Thomas, T. L.; Thompson, J.; Trippe, T. G.; Tuts, P. M.; Varelas, N.; Varnes, E. W.; Vititoe, D.; Volkov, A. A.; Vorobiev, A. P.; Wahl, H. D.; Wang, G.; Warchol, J.; Watts, G.; Wayne, M.; Weerts, H.; White, A.; White, J. T.; Wightman, J. A.; Willis, S.; Wimpenny, S. J.; Wirjawan, J. V.; Womersley, J.; Won, E.; Wood, D. R.; Xu, H.; Yamada, R.; Yamin, P.; Yang, J.; Yasuda, T.; Yepes, P.; Yoshikawa, C.; Youssef, S.; Yu, J.; Yu, Y.; Zhou, Z.; Zhu, Z. H.; Zieminska, D.; Zieminski, A.; Zverev, E. G.; Zylberstejn, A.

    1998-07-01

    We have searched for central production of a pair of photons with high transverse energies in pp¯ collisions at s = 1.8 TeV using 70 pb-1 of data collected with the D0 detector at the Fermilab Tevatron in 1994-1996. If they exist, virtual heavy pointlike Dirac monopoles could rescatter pairs of nearly real photons into this final state via a box diagram. We observe no excess of events above background, and set lower 95% C.L. limits of 610, 870, or 1580 GeV/c2 on the mass of a spin 0, 1/2, or 1 Dirac monopole.

  16. Scalar limitations of diffractive optical elements

    NASA Technical Reports Server (NTRS)

    Johnson, Eric G.; Hochmuth, Diane; Moharam, M. G.; Pommet, Drew

    1993-01-01

    In this paper, scalar limitations of diffractive optic components are investigated using coupled wave analyses. Results are presented for linear phase gratings and fanout devices. In addition, a parametric curve is given which correlates feature size with scalar performance.

  17. Optical diffraction by inhomogeneous volume objects

    NASA Astrophysics Data System (ADS)

    Forte, Gustavo; Lencina, Alberto; Tebaldi, Myrian; Bolognini, Nestor

    2008-08-01

    Electromagnetic waves propagation research in volume media increases considerably in the last years. The study evolved from thick hologram gratings, Bragg and Raman-Nath diffraction regimes up to current research in photonics materials. Usually differential methods are employed to account for the light transmitted for volume media. In our proposal, we develop a simple and versatile integral method to calculate the diffracted field provided the media refractive index has low variations in a wavelength scale. In fact, starting from first principles, we obtain a modified version of the Fresnel propagator of the scalar diffraction theory. Our method is valid for some kind of magnetic, dielectric and absorbent inhomogeneous media. In particular, for TE (TM) fields, we can study media where the permittivity (permeability) gradient is perpendicular to the electric (magnetic) field and its permeability (permittivity) is constant. To validate the approach, we applied it to (in) homogeneous media having well known diffraction properties.

  18. High-diffraction-efficiency pseudorandom encoding.

    PubMed

    Yang, Y; Stark, H; Gurkan, D; Lawson, C L; Cohn, R W

    2000-02-01

    Pseudorandom encoding (PRE) is a statistics-based procedure in which a pure-phase spatial light modulator (SLM) can yield, on the average, the prescribed diffraction pattern specified by the user. We seek to combine PRE with the optimization of an aperture-based target function. The target function is a fully complex input transmittance, unrealizable by a phase-only SLM, that generates a prescribed light intensity. The optimization is done to increase the diffraction efficiency of the overall process. We compare three optimization methods-Monte Carlo simulation, a genetic algorithm, and a gradient search-for maximizing the diffraction efficiency of a spot-array generator. Calculated solutions are then encoded by PRE, and the resulting diffraction patterns are computer simulated. Details on the complexity of each procedure are furnished, as well as comparisons on the quality, such as uniformity of the output spot array. PMID:10680630

  19. Tension in the LHC diffractive data?

    SciTech Connect

    Gotsman, Errol

    2015-04-10

    I discuss the LHC diffractive data, and compare it to predicted energy behaviour of various models. I suggest that the so called 'tension' between the experimental results, maybe due to the different Monte Carlo programs used.

  20. An Electronic Analog of the Diffraction Grating.

    ERIC Educational Resources Information Center

    MacLeod, A. M.

    1978-01-01

    Gives an outline description of electronic circuitry which is analogous to the optical diffraction grating or to crystals used in the Bragg reflection of X-rays or electron waves, and explains how to use it. (Author/GA)

  1. Electron Diffraction of Superfluid Helium Droplets

    PubMed Central

    2014-01-01

    We present experimental results of electron diffraction of superfluid helium droplets and droplets doped with phthalocyanine gallium chloride and discuss the possibility of performing the same experiment with a laser aligned sample. The diffraction profile of pure droplets demonstrates dependence on the nozzle temperature, that is, on the average size of the droplets. Larger clusters demonstrate faster decay with increasing momentum transfer, whereas smaller clusters converge to isolated gas phase molecules at source temperatures of 18 K and higher. Electron diffraction of doped droplets shows similar modified molecular scattering intensity as that of the corresponding gas phase molecules. On the basis of fittings of the scattering profile, the number of remaining helium atoms of the doped droplets is estimated to be on the order of hundreds. This result offers guidance in assessing the possibility of electron diffraction from laser aligned molecules doped in superfluid helium droplets. PMID:24920997

  2. Diffraction-limited ultrabroadband terahertz spectroscopy

    PubMed Central

    Baillergeau, M.; Maussang, K.; Nirrengarten, T.; Palomo, J.; Li, L. H.; Linfield, E. H.; Davies, A. G.; Dhillon, S.; Tignon, J.; Mangeney, J.

    2016-01-01

    Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 103. The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields. PMID:27142959

  3. Eyeglass. 1. Very large aperture diffractive telescopes.

    PubMed

    Hyde, R A

    1999-07-01

    The Eyeglass is a very large aperture (25-100-m) space telescope consisting of two distinct spacecraft, separated in space by several kilometers. A diffractive lens provides the telescope s large aperture, and a separate, much smaller, space telescope serves as its mobile eyepiece. Use of a transmissive diffractive lens solves two basic problems associated with very large aperture space telescopes; it is inherently launchable (lightweight, packagable, and deployable) it and virtually eliminates the traditional, very tight surface shape tolerances faced by reflecting apertures. The potential drawback to use of a diffractive primary (very narrow spectral bandwidth) is eliminated by corrective optics in the telescope s eyepiece; the Eyeglass can provide diffraction-limited imaging with either single-band (Deltalambda/lambda approximately 0.1), multiband, or continuous spectral coverage. PMID:18323902

  4. Electron backscatter diffraction: applications for nuclear materials.

    PubMed

    Medevielle; Hugon; Dugne

    1999-09-01

    The diffraction of electrons was first observed in 1928 by Kikuchi. The phenomenon results in the formation of characteristic diagrams of the crystalline lattice and the orientation of the phase. Backscattered electrons are diffracted by the different crystallographic planes (hkl) according to the Bragg angle thetab. These describe, by symmetry, two cones of axes normal to the diffracting plane. Information is collected on a phosphor screen, leading to the acquisition of a diffraction pattern called a Kikuchi diagram. Several improvements now give a wide range of applications such as phase identification (carbides or complex compounds in a (U,Zr,O) structure), analysis of materials interfaces (ZrO2/UO2), as well as solidification studies and local texture determination (molybdenum sheets). In these applications, EBSD, as a type of quantitative metallography, is a powerful tool. PMID:10460689

  5. Diffraction for a Neumann boundary condition

    SciTech Connect

    Lafitte, O.

    1997-11-01

    Let 0 be a bounded open set in R{sup n} and P be a constant coefficient operator of order 2 in R{sup n} x R{sub t} such that (P, {Omega}{sup c}) admits a strictly diffractive point. We calculate in this paper the principal symbol of the operator K transforming {partial_derivative}{sub n}u into u/{sub {partial_derivative}{Omega}} for a solution u of Pu = 0 in the neighborhood of a strictly diffractive point {rho}{sub 0} for (P, {Omega}{sup c}). We deduce from this calculation the principal symbol of the wave diffracted by a strictly convex analytic obstacle with a Neumann boundary condition. This result is used to calculate the electromagnetic wave diffracted by a perfectly conducting body. 7 refs., 2 figs.

  6. Diffraction-limited ultrabroadband terahertz spectroscopy

    NASA Astrophysics Data System (ADS)

    Baillergeau, M.; Maussang, K.; Nirrengarten, T.; Palomo, J.; Li, L. H.; Linfield, E. H.; Davies, A. G.; Dhillon, S.; Tignon, J.; Mangeney, J.

    2016-05-01

    Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 103. The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields.

  7. Dual-domain point diffraction interferometer.

    PubMed

    Naulleau, P P; Goldberg, K A

    1999-06-01

    The phase-shifting point diffraction interferometer has recently been developed and implemented at Lawrence Berkeley National Laboratory to meet the significant metrology challenge of characterizing extreme ultraviolet projection lithography systems. Here we present a refined version of this interferometer that overcomes the original design's susceptibility to noise attributed to scattered light. The theory of the new hybrid spatial- and temporal-domain (dual-domain) point diffraction interferometer is described in detail and experimental results are presented. PMID:18319953

  8. Nuclear diffractive structure functions at high energies

    SciTech Connect

    Marquet,C.; Kowalski, H.; Lappi, T.; Venugopalan, R.

    2008-08-08

    A future high-energy electron-ion collider would explore the non-linear weakly-coupled regime of QCD, and test the Color Glass Condensate (CGC) approach to high-energy scattering. Hard diffraction in deep inelastic scattering off nuclei will provide many fundamental measurements. In this work, the nuclear diffractive structure function F{sub 2,A}{sup D} is predicted in the CGC framework, and the features of nuclear enhancement and suppression are discussed.

  9. Simulating interference and diffraction in instructional laboratories

    NASA Astrophysics Data System (ADS)

    Maurer, L.

    2013-03-01

    Studieshave shown that standard lectures and instructional laboratory experiments are not effective at teaching interference and diffraction. In response, the author created an interactive computer program that simulates interference and diffraction effects using the finite difference time domain method. The software allows students to easily control, visualize and quantitatively measure the effects. Students collected data from simulations as part of their laboratory exercise, and they performed well on a subsequent quiz, showing promise for this approach.

  10. Diffraction pattern of gratings with erosion

    NASA Astrophysics Data System (ADS)

    Olivares-Pérez, Arturo; Fuentes-Tapia, Israel

    2015-03-01

    We present a theoretical study of amplitude diffraction gratings using computer simulating, which consists of a random sampling of points on the image grating to determine the points to be plotted and the points to remove, to simulate erosion in amplitude on the grating. We show their behavior in the diffraction patterns and the induced noise by limiting the number of points that representing the image of the eroded gratings and their symmetry.

  11. Observation of hard diffraction with CMS

    SciTech Connect

    Obertino, M. M.

    2009-03-23

    Diffraction with a hard scale can be observed in the first LHC data. We present studies of single diffractive W-boson production (pp{yields}Xp, with X including a W boson) and of {upsilon} photoproduction (pp{yields}{upsilon}p, with {upsilon}{yields}{mu}{sup +}{mu}{sup -}). The feasibility of observing these processes with the CMS detector using the first 100 pb{sup -1} of collected integrated luminosity for single interactions is discussed.

  12. Heavy Quarkonia on the Light Front

    NASA Astrophysics Data System (ADS)

    Li, Yang; Chen, Guangyao; Adhikari, Lekha; Zhao, Xingbo; Maris, Pieter; Vary, James

    2016-03-01

    We employ solutions for heavy quarkonium within a light-front basis function approach to compare with experiment and predict additional observables. The Hamiltonian is based on the Light-Front Holographic QCD (phenomenological confinement) plus one-gluon exchange. Mass spectra agree well with experiment and we employ the wavefunctions to evaluate decay constants and form factors. We discuss our progress and plans for evaluating generalized parton distributions (GPDs) and cross sections for diffractive production. Our predictions for these observables as well as predictions of additional excited states can be tested at ongoing and future experimental facilities, e.g., LHC, sPHENIX and the EIC. We acknowledge DOE Grants DE-FG02-87ER40371 & DESC0008485.

  13. FESDIF -- Finite Element Scalar Diffraction theory code

    SciTech Connect

    Kraus, H.G.

    1992-09-01

    This document describes the theory and use of a powerful scalar diffraction theory based computer code for calculation of intensity fields due to diffraction of optical waves by two-dimensional planar apertures and lenses. This code is called FESDIF (Finite Element Scalar Diffraction). It is based upon both Fraunhofer and Kirchhoff scalar diffraction theories. Simplified routines for circular apertures are included. However, the real power of the code comes from its basis in finite element methods. These methods allow the diffracting aperture to be virtually any geometric shape, including the various secondary aperture obstructions present in telescope systems. Aperture functions, with virtually any phase and amplitude variations, are allowed in the aperture openings. Step change aperture functions are accommodated. The incident waves are considered to be monochromatic. Plane waves, spherical waves, or Gaussian laser beams may be incident upon the apertures. Both area and line integral transformations were developed for the finite element based diffraction transformations. There is some loss of aperture function generality in the line integral transformations which are typically many times more computationally efficient than the area integral transformations when applicable to a particular problem.

  14. Diffraction Effects in a Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Haas, Michael R.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    This paper describes a numerical study of diffraction effects in the AIRES optical system using GLAD by Applied Optics Research. AIRES (or Airborne Infrared Echelle Spectrometer) employs two gratings in series. The small, first-order (i.e., predisperser) grating sorts orders for the large, high-order echelle grating, thus providing moderately high spectral resolution over 3.6 octaves in wavelength. The AIRES' optical design includes three field stops (i.e., a circular aperture and two long, narrow slits) and four pupil stops. A detailed diffraction analysis is required to evaluate critical trade-offs between spectral resolution, optical throughput, detector background, scattered light, and system size and weight. Such an analysis must consider diffraction effects at the pupil stops (edge diffraction), at the field stops (spatial filtering), and at intermediate positions where other optical elements are located. The effects of slit width, slit length, oversizing of the second slit relative to the first, baffling at the Lyot stop and subsequent pupil stops, and the necessity for oversizing other optical elements are presented and discussed. It is found that for narrow slits, the downstream energy distribution is significantly broadened relative to that for large slits, where telescope diffraction dominates, leading to significantly more light loss than anticipated, unless other key optical elements are oversized. The importance of performing a proper diffraction analysis is emphasized and the suitability of GLAD for this task is discussed.

  15. The early development of neutron diffraction: science in the wings of the Manhattan Project

    SciTech Connect

    Mason, T. E. Gawne, T. J.; Nagler, S. E.; Nestor, M. B.; Carpenter, J. M.

    2013-01-01

    Early neutron diffraction experiments performed in 1944 using the first nuclear reactors are described. Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan Project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurement of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor. Subsequent work by Wollan and Clifford G. Shull, who joined Wollan’s group at Oak Ridge in 1946, laid the foundations for widespread application of neutron diffraction as an important research tool.

  16. Cold Nuclear Matter Effects on Heavy Quark Production in Relativistic Heavy Ion Collisions

    NASA Astrophysics Data System (ADS)

    Durham, John Matthew

    2011-12-01

    The experimental collaborations at the Relativistic Heavy Ion Collider (RHIC) have established that dense nuclear matter with partonic degrees of freedom is formed in collisions of heavy nuclei at 200 GeV. Information from heavy quarks has given significant insight into the dynamics of this matter. Charm and bottom quarks are dominantly produced by gluon fusion in the early stages of the collision, and thus experience the complete evolution of the medium. The production baseline measured in p + p collisions can be described by fixed order plus next to leading log perturbative QCD calculations within uncertainties. In central Au+Au collisions, suppression has been measured relative to the yield in p + p scaled by the number of nucleon-nucleon collisions, indicating a significant energy loss by heavy quarks in the medium. The large elliptic flow amplitude v2 provides evidence that the heavy quarks flow along with the lighter partons. The suppression and elliptic flow of these quarks are in qualitative agreement with calculations based on Langevin transport models that imply a viscosity to entropy density ratio close to the conjectured quantum lower bound of 1/4pi. However, a full understanding of these phenomena requires measurements of cold nuclear matter (CNM) effects, which should be present in Au+Au collisions but are difficult to distinguish experimentally from effects due to interactions with the medium. This thesis presents measurements of electrons at midrapidity from the decays of heavy quarks produced in d+Au collisions at RHIC. A significant enhancement of these electrons is seen at a transverse momentum below 5 GeV/c, indicating strong CNM effects on charm quarks that are not present for lighter quarks. A simple model of CNM effects in Au+Au collisions suggests that the level of suppression in the hot nuclear medium is comparable for all quark flavors.

  17. Scientific Advancements and Technological Developments of High P-T Neutron Diffraction at LANSCE, Los Alamos

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Daemen, L. L.; Zhang, J.

    2003-12-01

    In-situ high P-T neutron diffraction experiments provide unique opportunities to study the crystal structure, hydrogen bonding, magnetism, and thermal parameters of light elements (eg. H, Li, B) and heavy elements (eg. Ta, U, Pu,), that are virtually impossible to determine with x-ray diffraction techniques. For example, thermoelasticity and Debye-Waller factor as function of pressure and temperature can be derived using in-situ high P-T neutron diffraction techniques. These applications can also be extended to a much broader spectrum of scientific problems. For instance, puzzles in Earth science such as the carbon cycle and the role of hydrous minerals for water exchange between lithosphere and biosphere can be directly addressed. Moreover, by introducing in-situ shear, texture of metals and minerals accompanied with phase transitions at high P-T conditions can also be studied by high P-T neutron diffraction. We have successfully conducted high P-T neutron diffraction experiments at LANSCE and achieved simultaneous high pressures and temperatures of 10 GPa and 1500 K. With an average 3-6 hours of data collection, the diffraction data are of sufficiently high quality for the determination of structural parameters and thermal vibrations. We have studied hydrous mineral (MgOD), perovskite (K.15,Na.85)MgF3, clathrate hydrates (CH4-, CO2-, and H2-), metals (Mo, Al, Zr), and amorphous materials (carbon black, BMG). The aim of our research is to accurately map bond lengths, bond angles, neighboring atomic environments, and phase stability in P-T-X space. Studies based on high-pressure neutron diffraction are important for multi-disciplinary science and we welcome researchers from all fields to use this advanced technique. We have developed a 500-ton toroidal press, TAP-98, to conduct simultaneous high P-T neutron diffraction experiments inside of HIPPO (High-Pressure and Preferred-Orientation diffractometer). We have also developed a large gem-crystal anvil cell, ZAP-01

  18. UNIVERSAL BEHAVIOR OF CHARGED PARTICLE PRODUCTION IN HEAVY ION COLLISIONS.

    SciTech Connect

    STEINBERG,P.A.FOR THE PHOBOS COLLABORATION

    2002-07-24

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at {radical}(s{sub NN}) = 19.6, 130 and 200 GeV. Two observations indicate universal behavior of charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/{bar p}p and e{sup +}e{sup -} data. / in nuclear collisions at high energy scales with {radical}s in a similar way as N{sub ch} in e{sup +}e{sup -} collisions and has a very weak centrality dependence. These features may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

  19. Universal behavior of charged particle production in heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Phobos Collaboration; Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at sqrt(s_NN) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

  20. Heavy Vehicle Propulsion Materials

    SciTech Connect

    Ray Johnson

    2000-01-31

    The objectives are to Provide Key Enabling Materials Technologies to Increase Energy Efficiency and Reduce Exhaust Emissions. The following goals are listed: Goal 1: By 3rd quarter 2002, complete development of materials enabling the maintenance or improvement of fuel efficiency {ge} 45% of class 7-8 truck engines while meeting the EPA/Justice Department ''Consent Decree'' for emissions reduction. Goal 2: By 4th quarter 2004, complete development of enabling materials for light-duty (class 1-2) diesel truck engines with efficiency over 40%, over a wide range of loads and speeds, while meeting EPA Tier 2 emission regulations. Goal 3: By 4th quarter 2006, complete development of materials solutions to enable heavy-duty diesel engine efficiency of 50% while meeting the emission reduction goals identified in the EPA proposed rule for heavy-duty highway engines.''

  1. Detecting heavy quarks

    SciTech Connect

    Benenson, G.; Chau, L.L.; Ludlam, T.; Paige, F.E.; Platner, E.D.; Protopopescu, S.D.; Rehak, P.

    1983-01-01

    In this exercise we examine the performance of a detector specifically configured to tag heavy quark (HQ) jets through direct observations of D-meson decays with a high resolution vertex detector. To optimize the performance of such a detector, we assume the small diamond beam crossing configuration as described in the 1978 ISABELLE proposal, giving a luminosity of 10/sup 32/ cm/sup -2/ sec/sup -1/. Because of the very large backgrounds from light quark (LQ) jets, most triggering schemes at this luminosity require high P/sub perpendicular to/ leptons and inevitably give missing neutrinos. If alternative triggering schemes could be found, then one can hope to find and calculate the mass of objects decaying to heavy quarks. A scheme using the high resolution detector will also be discussed in detail. The study was carried out with events generated by the ISAJET Monte Carlo and a computer simulation of the described detector system. (WHK)

  2. Utah Heavy Oil Program

    SciTech Connect

    J. Bauman; S. Burian; M. Deo; E. Eddings; R. Gani; R. Goel; C.K. Huang; M. Hogue; R. Keiter; L. Li; J. Ruple; T. Ring; P. Rose; M. Skliar; P.J. Smith; J.P. Spinti; P. Tiwari; J. Wilkey; K. Uchitel

    2009-10-20

    The Utah Heavy Oil Program (UHOP) was established in June 2006 to provide multidisciplinary research support to federal and state constituents for addressing the wide-ranging issues surrounding the creation of an industry for unconventional oil production in the United States. Additionally, UHOP was to serve as an on-going source of unbiased information to the nation surrounding technical, economic, legal and environmental aspects of developing heavy oil, oil sands, and oil shale resources. UHOP fulGilled its role by completing three tasks. First, in response to the Energy Policy Act of 2005 Section 369(p), UHOP published an update report to the 1987 technical and economic assessment of domestic heavy oil resources that was prepared by the Interstate Oil and Gas Compact Commission. The UHOP report, entitled 'A Technical, Economic, and Legal Assessment of North American Heavy Oil, Oil Sands, and Oil Shale Resources' was published in electronic and hard copy form in October 2007. Second, UHOP developed of a comprehensive, publicly accessible online repository of unconventional oil resources in North America based on the DSpace software platform. An interactive map was also developed as a source of geospatial information and as a means to interact with the repository from a geospatial setting. All documents uploaded to the repository are fully searchable by author, title, and keywords. Third, UHOP sponsored Give research projects related to unconventional fuels development. Two projects looked at issues associated with oil shale production, including oil shale pyrolysis kinetics, resource heterogeneity, and reservoir simulation. One project evaluated in situ production from Utah oil sands. Another project focused on water availability and produced water treatments. The last project considered commercial oil shale leasing from a policy, environmental, and economic perspective.

  3. Heavy rain field measurements

    NASA Technical Reports Server (NTRS)

    Melson, ED

    1991-01-01

    A weight-measuring rain gauge was developed to collect rain data and configured to operate at a high sample rate (one sample pre second). Instead of averaging the rain rate in minutes, hours, and sometime days as normally performed, the rain data collected are examined in seconds. The results of six field sites are compiled. Rain rate levels, duration of downpours, and frequency of heavy rainfall events are presented.

  4. Overview Of Diffractive Optics At Honeywell

    NASA Astrophysics Data System (ADS)

    Cox, J. Allen

    1988-05-01

    Interest in holographic, or diffractive, optics has been rekindled in the last few years with demonstrated advances in three areas: computer-aided design (CAD) tools, VLSI lithographic and dry etching processes, and mathematical modeling of diffractive elements.1 The availability of CAD tools and electron-beam lithography led first to the emergence of computer-generated holography (CGH). CGH work at Honeywell was started and brought to maturity by Arnold2 in 1980-1983. However, because of the inherently low diffraction efficiency (-10%), lithographic CGHs have found a place in only a relatively few practical applications, such as testing diamond turned aspherics, and thus CGHs have not been widely accepted within industry. The first step in changing this situation came in the 1970s with numerical approaches to rigorously solve the vector field equations for diffraction from blazed gratings.3 The extensive numerical results from these models not only showed that high diffraction efficiencies are possible with etched surface profiles, but also indicated the sensitivity to various profile configurations and design parameters. Veldkamp et al.1,4'-'61 at MIT Lincoln Laboratories have taken the final step necessary to establish the practical feasibility of diffractive optics by using reactive ion etching techniques to produce the surface profiles prescribed by the numerical models and delineated by CGH lithographic masks. With this combined approach, they have demonstrated the feasibility of high-efficiency diffractive elements for a variety of diverse applications, such as the CO2 laser radar telescope,4 coherent beam addition of laser diode arrays,5 and on-axis, broadband, aspheric lens elements for infrared imagers.6 These elements are fabricated using well-established VLSI lithographic and dry etching techniques. Moreover, the ability to replicate each diffractive element provides the potential for high-volume, low-cost producibility. With this precedent, Honeywell

  5. Validation of three-dimensional diffraction contrast tomography reconstructions by means of electron backscatter diffraction characterization

    PubMed Central

    Syha, Melanie; Trenkle, Andreas; Lödermann, Barbara; Graff, Andreas; Ludwig, Wolfgang; Weygand, Daniel; Gumbsch, Peter

    2013-01-01

    Microstructure reconstructions resulting from diffraction contrast tomography data of polycrystalline bulk strontium titanate were reinvestigated by means of electron backscatter diffraction (EBSD) characterization. Corresponding two-dimensional grain maps from the two characterization methods were aligned and compared, focusing on the spatial resolution at the internal interfaces. The compared grain boundary networks show a remarkably good agreement both morphologically and in crystallographic orientation. Deviations are critically assessed and discussed in the context of diffraction data reconstruction and EBSD data collection techniques. PMID:24046507

  6. Diffraction on heavy samples at STRESS-SPEC using a robot system

    NASA Astrophysics Data System (ADS)

    Al-Hamdany, N.; Gan, W. M.; Randau, C.; Brokmeier, H.-G.; Hofmann, M.

    2015-04-01

    The material science diffractometer STRESS-SPEC has high flux and a high flexible monochromator arrangement to optimize the needed wavelength. Many specific sample handling stages and sample environments are available. One of them is a Staubli RX 160 robot with nominal load capacity of 20 kg and more freedom for texture mapping than the Huber 512 Eulerian type cradle. Demonstration experiments of non-destructive pole figures and strain measurements of Cu-tube segments weighing 12 kg weight and 250 mm in length and 140 mm diameter have been carried out. The residual strains measured by the robot and by the XYZ- stage fit quite well, that means the robot is reliable for strain measurements. The texture of the Cu-tube has dominant recrystallization texture components represented by the cube and the rotated cube.

  7. Structured illumination diffraction phase microscopy for broadband, sub-diffraction resolution, quantitative phase imaging

    PubMed Central

    Chowdhury, Shwetadwip; Izatt, Joseph A.

    2015-01-01

    Structured illumination microscopy (SIM) is an established technique that allows sub-diffraction resolution imaging by heterodyning high sample frequencies into the system’s passband via structured illumination. However, until now, SIM has been typically used to achieve sub-diffraction resolution for intensity-based imaging. Here, we present a novel optical setup that uses structured illumination with a broadband-light source to obtain noise-reduced, sub-diffraction resolution, quantitative-phase (QPM) imaging of cells. We compare this with a previous work for sub-diffraction QPM imaging via SIM that used a laser source, and was thus still corrupted by coherent noise. PMID:24562266

  8. Breakdown of partial conservation of axial current in diffractive neutrino interactions

    SciTech Connect

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan; Siddikov, M.

    2011-08-15

    We test the hypothesis of partially conserved axial current in high-energy diffractive neutrino production of pions. Since the pion pole contribution to the Adler relation (AR) is forbidden by conservation of the lepton current, the heavier states, like the a{sub 1} pole, {rho}-{pi} cut, etc., control the lifetime of the hadronic fluctuations of the neutrino. We evaluate the deviation from the AR in diffractive neutrino production of pions on proton and nuclear targets. At high energies, when all the relevant time scales considerably exceed the size of the target, the AR explicitly breaks down on an absorptive target, such as a heavy nucleus. In this regime, close to the black disk limit, the off-diagonal diffractive amplitudes vanish, while the diagonal one, {pi}{yields}{pi}, which enters the AR, maximizes and saturates the unitarity bound. At lower energies, in the regime of short lifetime of heavy hadronic fluctuations the AR is restored, i.e., it is not altered by the nuclear effects.

  9. Multiwavelength anomalous diffraction analyses of protein structures based on xenon and selenium resonances

    NASA Astrophysics Data System (ADS)

    Slama, Betty Nicole

    The 'phase problem' is central to X-ray crystallography, and multiwavelength anomalous diffraction (MAD) provides an elegant and broadly accessible solution. In the first part, the use of MAD at the xenon L3 edge is explored, as an alternative to the well established selenium K-edge phasing. In the second part, the structure of the bacterial protein Vibrio cholerae LuxQ, part of a two component signaling system involved in quorum sensing, is solved and analyzed. Keywords: anomalous scattering, x-ray diffraction, phasing, protein structure.

  10. Single crystal diffraction by synchrotron radiation

    SciTech Connect

    Kvick, A.

    1988-01-01

    The tunability and access to short wavelengths in combination with high intensity and the low divergence of the x-ray radiation produced by synchrotron storage rings opens up new and challenging fields for single crystal diffraction. These areas include microcrystal diffraction, studies of time-dependent phenomena, element selective diffraction, studies of materials under extreme conditions, solution of the crystallographic phase problem either by the use of the wavelength dependency of the anomalous scattering or by direct experimental determination of the phases. Single crystal diffraction from proteins and macromolecules using photographic film as a detection medium has already reached considerable maturity, but high-precision data collections using diffractometers at storage rings are still not routine because of the severe requirements for beam stability over extended periods of time. Development work at institutions such as the National Synchrotron Light Source, The Photon Factory, SSRL, CHESS, Hasylab and Daresbury, however, suggest that synchrotron single-crystal diffraction will become an essential part of the research at the synchrotron storage rings in the near future. 9 refs., 2 figs.

  11. Optimization Algorithm for Designing Diffractive Optical Elements

    NASA Astrophysics Data System (ADS)

    Agudelo, Viviana A.; Orozco, Ricardo Amézquita

    2008-04-01

    Diffractive Optical Elements (DOEs) are commonly used in many applications such as laser beam shaping, recording of micro reliefs, wave front analysis, metrology and many others where they can replace single or multiple conventional optical elements (diffractive or refractive). One of the most versatile way to produce them, is to use computer assisted techniques for their design and optimization, as well as optical or electron beam micro-lithography techniques for the final fabrication. The fundamental figures of merit involved in the optimization of such devices are both the diffraction efficiency and the signal to noise ratio evaluated in the reconstructed wave front at the image plane. A design and optimization algorithm based on the error—reduction method (Gerchberg and Saxton) is proposed to obtain binary discrete phase-only Fresnel DOEs that will be used to produce specific intensity patterns. Some experimental results were obtained using a spatial light modulator acting as a binary programmable diffractive phase element. Although the DOEs optimized here are discrete in phase, they present an acceptable signal noise relation and diffraction efficiency.

  12. Surface diffusion studies by optical diffraction techniques

    SciTech Connect

    Xiao, X.D.

    1992-11-01

    The newly developed optical techniques have been combined with either second harmonic (SH) diffraction or linear diffraction off a monolayer adsorbate grating for surface diffusion measurement. Anisotropy of surface diffusion of CO on Ni(l10) was used as a demonstration for the second harmonic dim reaction method. The linear diffraction method, which possesses a much higher sensitivity than the SH diffraction method, was employed to study the effect of adsorbate-adsorbate interaction on CO diffusion on Ni(l10) surface. Results showed that only the short range direct CO-CO orbital overlapping interaction influences CO diffusion but not the long range dipole-dipole and CO-NI-CO interactions. Effects of impurities and defects on surface diffusion were further explored by using linear diffraction method on CO/Ni(110) system. It was found that a few percent S impurity can alter the CO diffusion barrier height to a much higher value through changing the Ni(110) surface. The point defects of Ni(l10) surface seem to speed up CO diffusion significantly. A mechanism with long jumps over multiple lattice distance initiated by CO filled vacancy is proposed to explain the observed defect effect.

  13. Hard diffraction and deep inelastic scattering

    SciTech Connect

    Bjorken, J.D.

    1994-04-01

    Since the advent of hard-collision physics, the study of diffractive processes - shadow physics - has been less prominent than before. However, there is now a renewed interest in the subject, especially in that aspect which synthesizes the short-distance, hard-collision phenomena with the classical physics of large rapidity-gaps. This is especially stimulated by the recent data on deep-inelastic scattering from HERA, as well as the theoretical work which relates to it. The word diffraction is sometimes used by high-energy physicists in a loose way. The author defines this term to mean: A diffractive process occurs if and only if there is a large rapidity gap in the produced-particle phase space which is not exponentially suppressed. Here a rapidity gap means essentially no hadrons produced into the rapidity gap (which operates in the {open_quotes}lego{close_quotes} phase-space of pseudo-rapidity and azimuthal angle). And non-exponential suppression implies that the cross-section for creating a gap with width {Delta}{eta} does not have a power-law decrease with increasing subenergy s=e{sup {Delta}{eta}}, but behaves at most like some power of pseudorapidity {Delta}{eta}{approx}log(s). The term hard diffraction shall simply refer to those diffractive process which have jets in the final-state phase-space.

  14. The charge density of urea from synchrotron diffraction data.

    PubMed

    Birkedal, Henrik; Madsen, Dennis; Mathiesen, Ragnvald H; Knudsen, Kenneth; Weber, Hans-Peter; Pattison, Philip; Schwarzenbach, Dieter

    2004-09-01

    The charge density of urea is studied using very high precision single-crystal synchrotron-radiation diffraction data collected at the Swiss-Norwegian Beam Lines at ESRF. An unprecedented resolution of 1.44 A(-1) in sin theta;/lambda is obtained at 123 K. The optimization of the experiment for charge-density studies is discussed. The high precision of the data allowed the refinement of a multipole model extending to hexadecapoles and quadrupoles on the heavy and H atoms, respectively, as well as a liberal treatment of radial functions. The topological properties of the resulting electron density are analysed and compared with earlier experimental results as well as with periodic Hartree-Fock calculations. The properties of the strongly polarized C-O bond agree with trends derived from previous experimental results while the ab initio calculations differ significantly. The results indicate that the description of the C-O bond requires more flexible basis sets in the theoretical calculations. The calculated integrated atomic charges are much larger than the observed ones. It is suggested that the present experimental results provide new target values for validation of future ab initio calculations. The molecular dipole moment derived from the integrated atomic properties is the same as the one obtained from the multipole model even though the individual atomic contributions differ. Comparison with literature data for urea in solution and the gas phase yields a dipole enhancement in the solid of about 1.5 D. The thermal expansion of urea is determined using synchrotron powder diffraction data. With decreasing temperature, an increasing anisotropic strain is observed. PMID:15477674

  15. Oxygen as a site specific structural probe in neutron diffraction

    SciTech Connect

    Neuefeind, Joerg C; Simonson, J Michael {Mike}; Salmon, Phil; Zeidler, Anita; Fischer, Henry E; Rauch, Helmut; Markland, Thomas; Lemmel, Hartmut

    2011-01-01

    Oxygen is a ubiquitous element, playing an essential role in most scientific and technological disciplines, and is often incorporated within a structurally disordered material where examples include molten silicates in planetary science, glasses used for lasers and optical communication, and water in biological processes. Establishing the structure of a liquid or glassy oxide and thereby its relation to the functional properties of a material is not, however, a trivial task owing to the complexity associated with atomic disorder. Here we approach this challenge by measuring the bound coherent neutron scattering lengths of the oxygen isotopes with the sensitive technique of neutron interferometry. We find that there is a small but finite contrast of 0.204(6) fm between the scattering lengths of the isotope 18O and oxygen of natural isotopic abundance natO, contrary to tables of recommended values. This has enabled us to investigate the structure of both light and heavy water by exploiting, for the first time, the method of oxygen isotope substitution in neutron diffraction, thus circumventing many of the significant problems associated with more traditional methods in which hydrogen is substituted by deuterium. We find a difference of ~0.5% between the O-H and O-D intra-molecular bond distances which is much smaller than recent estimates based on diffraction data and is found to be in excellent agreement with path integral molecular dynamics simulations made with a flexible polarisable water model. Our results demonstrate the potential for using oxygen isotope substitution as a powerful and effective site specific probe in a plethora of materials, of pertinence as instrumentation at next generation neutron sources comes online

  16. Heavy-flavor observables at RHIC and LHC

    NASA Astrophysics Data System (ADS)

    Nahrgang, Marlene; Aichelin, Jörg; Bass, Steffen; Gossiaux, Pol Bernard; Werner, Klaus

    2014-11-01

    We investigate the charm-quark propagation in the QGP media produced in ultrarelativistic heavy-ion collisions at RHIC and the LHC. Purely collisional and radiative processes lead to a significant suppression of final D-meson spectra at high transverse momentum and a finite flow of heavy quarks inside the fluid dynamical evolution of the light partons. The D-meson nuclear modification factor and the elliptic flow are studied at two collision energies. We further propose to measure the triangular flow of D mesons, which we find to be nonzero in non-central collisions.

  17. Heavy ions at steamboat: summary of parallel sessions

    SciTech Connect

    Ludlam, T.W.

    1984-01-01

    The interest in heavy ions at the intersection between particle and nuclear physics is motivated by the opportunity for an entirely new approach to the understanding of fundamental interactions by studying extreme states of nuclear matter. At this conference we have seen important new results on some of the central issues including: (1) how well can we predict the landscape of the extremes - that is, the phase structure of QCD and nuclear matter; (2) can we explore it with heavy ion collisions; and (3) can we recognize the appearance of new terrain. Our present understanding of the behavior of nuclear matter under extreme conditions is briefly discussed. 16 references. (WHK)

  18. Heavy precipitation events in northern Switzerland

    NASA Astrophysics Data System (ADS)

    Giannakaki, Paraskevi; Martius, Olivia

    2013-04-01

    Heavy precipitation events in the Alpine region often cause floods, rock-falls and mud slides with severe consequences for population and economy. Breaking synoptic Rossby waves located over western Europe, play a central role in triggering such heavy rain events in southern Switzerland (e.g. Massacand et al. 1998). In contrast, synoptic scale structures triggering heavy precipitation on the north side of the Swiss Alps and orographic effects have so far not been studied comprehensively. An observation based high resolution precipitation data set for Switzerland and the Alps (MeteoSwiss) is used to identify heavy precipitation events affecting the north side of the Swiss Alps for the time period 1961-2010. For these events a detailed statistical and dynamical analysis of the upper level flow is conducted using ECMWFs ERA-40 and ERA-Interim reanalysis data sets. For the analysis north side of the Swiss Alps is divided in two investigation areas north-eastern and western Switzerland following the Swiss climate change scenarios (Bey et al. 2011). A subjective classification of upper level structures triggering heavy precipitation events in the areas of interest is presented. Four classes are defined based on the orientation and formation of the dynamical tropopause during extreme events in the northern part of Switzerland and its sub-regions. The analysis is extended by a climatology of breaking waves and cut-offs following the method of Wernli and Sprenger (2007) to examine their presence and location during extreme events. References Bey I., Croci-Maspoli M., Fuhrer J., Kull C, Appenzeller C., Knutti R. and Schär C. Swiss Climate Change Scenarios CH2011, C2SM, MeteoSwiss, ETH, NCCR Climate, OcCC (2011), http://dx.doi.org/10.3929/ethz-a-006720559 Massacand A., H. Wernli, and H.C. Davies, 1998. Heavy precipitation on the Alpine South side: An upper-level precursor. Geophys. Res. Lett., 25, 1435-1438. MeteoSwiss 2011. Documentation of Meteoswiss grid-data products

  19. Adaptable Diffraction Gratings With Wavefront Transformation

    NASA Technical Reports Server (NTRS)

    Iazikov, Dmitri; Mossberg, Thomas W.; Greiner, Christoph M.

    2010-01-01

    Diffraction gratings are optical components with regular patterns of grooves, which angularly disperse incoming light by wavelength. Traditional diffraction gratings have static planar, concave, or convex surfaces. However, if they could be made so that they can change the surface curvature at will, then they would be able to focus on particular segments, self-calibrate, or perform fine adjustments. This innovation creates a diffraction grating on a deformable surface. This surface could be bent at will, resulting in a dynamic wavefront transformation. This allows for self-calibration, compensation for aberrations, enhancing image resolution in a particular area, or performing multiple scans using different wavelengths. A dynamic grating gives scientists a new ability to explore wavefronts from a variety of viewpoints.

  20. The dynamics of diffracted rays in foams

    NASA Astrophysics Data System (ADS)

    Tufaile, A.; Tufaile, A. P. B.

    2015-12-01

    We have studied some aspects of the optics of the light scattering in foams. This paper describes the difference between rays and diffracted rays from the point of view of geometrical theory of diffraction. We have represented some bifurcations of light rays using dynamical systems. Based on our observations of foams, we created a solid optical device. The interference patterns of light scattering in foams forming Airy fringes were explored observing the pattern named as the eye of Horus. In the cases we examine, these Airy fringes are associated with light scattering in curved surfaces, while the halo formation is related to the law of edge diffraction. We are proposing a Pohl interferometer using a three-sided bubble/Plateau border system.

  1. Diffraction efficiency of bacteriorhodopsin and its analogs

    NASA Astrophysics Data System (ADS)

    Bunkin, F. V.; Vsevolodov, N. N.; Druzhko, A. B.; Mitsner, B. I.; Prokhorov, A. M.; Savranskii, V. V.; Tkachenko, N. V.; Shevchenko, T. B.

    1981-12-01

    Bacteriorhodopsin is proposed for optical information recording, and a preliminary study of its diffraction efficiency is reported. Second-harmonic coherent beams of equal intensity from a single-mode pulsed YAG:Nd laser were passed through a 30-100 micron thick sample prepared from purple membranes removed from Halobacterium halobium, and through an artificially synthesized complex of 4-methoxyretinol and bacteriorhodopsin. The dependence of the diffraction efficiency on the energy density of the exposure was measured. The photosensitivity of the samples was estimated and compared with the experimental results, and it is found that for the modified sample, the results of the experiment can be attributed to a change in the absorption coefficient, while for the native sample the diffraction is due to a change in the refractive index.

  2. Phase function encoding of diffractive structures.

    PubMed

    Schilling, A; Herzig, H P

    2000-10-10

    We analyzed the direct sampling (DS) method for diffractive lens encoding, using exact electromagnetic diffraction theory. In addition to previously published research [Pure Appl. Opt. 7, 565 (1998)] we present what we believe to be new results for TM polarization. We found that the validity of the scalar-based DS method is even more extended for TM than for TE polarization. Additionally, we fabricated and characterized DS-encoded blazed gratings and found good agreement between the experimental and theoretical diffraction efficiencies. We analyzed quantitatively the influence of the encoding schemes DS and analytic quantization (AQ) on the quality of the focal spot. We also investigated the focal spot sizes (FWHM) and the Strehl ratios of the DS- and the AQ-encoded cylindrical lenses. PMID:18354523

  3. The design of macromolecular crystallography diffraction experiments

    SciTech Connect

    Evans, Gwyndaf Axford, Danny; Owen, Robin L.

    2011-04-01

    Thoughts about the decisions made in designing macromolecular X-ray crystallography experiments at synchrotron beamlines are presented. The measurement of X-ray diffraction data from macromolecular crystals for the purpose of structure determination is the convergence of two processes: the preparation of diffraction-quality crystal samples on the one hand and the construction and optimization of an X-ray beamline and end station on the other. Like sample preparation, a macromolecular crystallography beamline is geared to obtaining the best possible diffraction measurements from crystals provided by the synchrotron user. This paper describes the thoughts behind an experiment that fully exploits both the sample and the beamline and how these map into everyday decisions that users can and should make when visiting a beamline with their most precious crystals.

  4. Diffraction of entangled particles by light gratings

    SciTech Connect

    Sancho, Pedro

    2015-04-15

    We analyze the diffraction regime of the Kapitza–Dirac effect for particles entangled in momentum. The detection patterns show two-particle interferences. In the single-mode case we identify a discontinuity in the set of joint detection probabilities, associated with the disconnected character of the space of non-separable states. For Gaussian multi-mode states we derive the diffraction patterns, providing an example of the dependence of the light–matter interaction on entanglement. When the particles are identical, we can explore the relation between exchange and entanglement effects. We find a complementary behavior between overlapping and Schmidt’s number. In particular, symmetric entanglement can cancel the exchange effects. - Highlights: • Kapitza–Dirac diffraction of entangled particles shows multiparticle interference. • There is a discontinuity in the set of joint detection patterns of entangled states. • We find a complementary behavior between overlapping and Schmidt’s number. • Symmetric entanglement can cancel the exchange effects.

  5. The design of macromolecular crystallography diffraction experiments

    PubMed Central

    Evans, Gwyndaf; Axford, Danny; Owen, Robin L.

    2011-01-01

    The measurement of X-ray diffraction data from macro­molecular crystals for the purpose of structure determination is the convergence of two processes: the preparation of diffraction-quality crystal samples on the one hand and the construction and optimization of an X-ray beamline and end station on the other. Like sample preparation, a macromolecular crystallography beamline is geared to obtaining the best possible diffraction measurements from crystals provided by the synchrotron user. This paper describes the thoughts behind an experiment that fully exploits both the sample and the beamline and how these map into everyday decisions that users can and should make when visiting a beamline with their most precious crystals. PMID:21460444

  6. Higher order diffractions from a circular disk

    NASA Technical Reports Server (NTRS)

    Marsland, Diane P.; Balanis, Constantine A.; Brumley, Stephen A.

    1987-01-01

    The backscattering from a circular disk is analyzed using the geometrical theory of diffraction. First-, second-, and third-order diffractions are included in the hard polarization analysis, while first-, second-, and third-order slope diffractions are included for soft polarization. Improvements in the prediction of the monostatic radar cross section over previous works are noted. For hard polarization, an excellent agreement is exhibited between experimental and theoretical results, while a very good agreement is noted for soft polarization. To further improve the soft polarization results for wide angles, a model for the creeping wave or circulating current on the edge of the disk is obtained and used to find an additional component of the backscattered field. The addition of this component significantly improves the results for wide angles, leading to excellent agreement for soft polarization also. An axial-caustic correction method using equivalent currents is also included in the analysis.

  7. Ultra-high density diffraction grating

    DOEpatents

    Padmore, Howard A.; Voronov, Dmytro L.; Cambie, Rossana; Yashchuk, Valeriy V.; Gullikson, Eric M.

    2012-12-11

    A diffraction grating structure having ultra-high density of grooves comprises an echellette substrate having periodically repeating recessed features, and a multi-layer stack of materials disposed on the echellette substrate. The surface of the diffraction grating is planarized, such that layers of the multi-layer stack form a plurality of lines disposed on the planarized surface of the structure in a periodical fashion, wherein lines having a first property alternate with lines having a dissimilar property on the surface of the substrate. For example, in one embodiment, lines comprising high-Z and low-Z materials alternate on the planarized surface providing a structure that is suitable as a diffraction grating for EUV and soft X-rays. In some embodiments, line density of between about 10,000 lines/mm to about 100,000 lines/mm is provided.

  8. Data Exploration Toolkit for serial diffraction experiments

    DOE PAGESBeta

    Zeldin, Oliver B.; Brewster, Aaron S.; Hattne, Johan; Uervirojnangkoorn, Monarin; Lyubimov, Artem Y.; Zhou, Qiangjun; Zhao, Minglei; Weis, William I.; Sauter, Nicholas K.; Brunger, Axel T.

    2015-01-23

    Ultrafast diffraction at X-ray free-electron lasers (XFELs) has the potential to yield new insights into important biological systems that produce radiation-sensitive crystals. An unavoidable feature of the 'diffraction before destruction' nature of these experiments is that images are obtained from many distinct crystals and/or different regions of the same crystal. Combined with other sources of XFEL shot-to-shot variation, this introduces significant heterogeneity into the diffraction data, complicating processing and interpretation. To enable researchers to get the most from their collected data, a toolkit is presented that provides insights into the quality of, and the variation present in, serial crystallography datamore » sets. These tools operate on the unmerged, partial intensity integration results from many individual crystals, and can be used on two levels: firstly to guide the experimental strategy during data collection, and secondly to help users make informed choices during data processing.« less

  9. Fabrication techniques for very fast diffractive lenses

    NASA Technical Reports Server (NTRS)

    Tai, Anthony M.; Marron, Joseph C.

    1993-01-01

    Aspheric lenses with arbitrary phase functions can be fabricated on thin light weight substrates via the binary optics fabrication technique. However, it is difficult and costly to fabricate a fast lens (f/number less than 1) for use as the shorter wavelengths. The pitch of the masks and the alignment accuracy must be very fine. For a large lens, the space-bandwidth product of the element can also become impractically large. In this paper, two alternate approaches for the fabrication of fast aspheric diffractive lenses are described. The first approach fabricates the diffractive lens interferometrically, utilizing a spherical wavefront to provide the optical power of the lens and a computer generated hologram to create the aspheric components. The second approach fabricates the aspheric diffractive lens in the form if a higher order kinoform which trades groove profile fidelity for coarser feature size. The design and implementation issues for these two fabrication techniques are discussed.

  10. Beyond the diffraction limit via optical amplification.

    PubMed

    Kellerer, Aglaé N; Ribak, Erez N

    2016-07-15

    In a previous article [Astron. Astrophys.561, A118 (2014)], we suggested a method to overcome the diffraction limit behind a telescope. We discuss and extend recent numerical simulations and test whether it is indeed possible to use photon amplification to enhance the angular resolution of a telescope or a microscope beyond the diffraction limit. An essential addition is the proposal to select events with an above-average ratio of stimulated to spontaneous photons. The analysis shows that the diffraction limit of a telescope is surpassed by a factor of 10 for an amplifier gain of 200, if the analysis is restricted to a tenth of the incoming astronomical photons. A gain of 70 is sufficient with a hundredth of the photons. More simulations must be performed to account for the bunching of spontaneous photons. PMID:27420490

  11. Data Exploration Toolkit for serial diffraction experiments

    PubMed Central

    Zeldin, Oliver B.; Brewster, Aaron S.; Hattne, Johan; Uervirojnangkoorn, Monarin; Lyubimov, Artem Y.; Zhou, Qiangjun; Zhao, Minglei; Weis, William I.; Sauter, Nicholas K.; Brunger, Axel T.

    2015-01-01

    Ultrafast diffraction at X-ray free-electron lasers (XFELs) has the potential to yield new insights into important biological systems that produce radiation-sensitive crystals. An unavoidable feature of the ‘diffraction before destruction’ nature of these experiments is that images are obtained from many distinct crystals and/or different regions of the same crystal. Combined with other sources of XFEL shot-to-shot variation, this introduces significant heterogeneity into the diffraction data, complicating processing and interpretation. To enable researchers to get the most from their collected data, a toolkit is presented that provides insights into the quality of, and the variation present in, serial crystallography data sets. These tools operate on the unmerged, partial intensity integration results from many individual crystals, and can be used on two levels: firstly to guide the experimental strategy during data collection, and secondly to help users make informed choices during data processing. PMID:25664746

  12. Heavy Truck Engine Program

    SciTech Connect

    Nelson, Christopher

    2009-01-08

    The Heavy Duty Truck Engine Program at Cummins embodied three significant development phases. All phases of work strove to demonstrate a high level of diesel engine efficiency in the face of increasingly stringent emission requirements. Concurrently, aftertreatment system development and refinement was pursued in support of these efficiency demonstrations. The program's first phase focused on the demonstration in-vehicle of a high level of heavy duty diesel engine efficiency (45% Brake Thermal Efficiency) at a typical cruise condition while achieving composite emissions results which met the 2004 U.S. EPA legislated standards. With a combination of engine combustion calibration tuning and the development and application of Urea-based SCR and particulate aftertreatment, these demonstrations were successfully performed by Q4 of 2002. The second phase of the program directed efforts towards an in-vehicle demonstration of an engine system capable of meeting 2007 U.S. EPA legislated emissions requirements while achieving 45% Brake Thermal Efficiency at cruise conditions. Through further combustion optimization, the refinement of Cummins Cooled EGR architecture, the application of a high pressure common rail fuel system and the incorporation of optimized engine parasitics, Cummins Inc. successfully demonstrated these deliverables in Q2 of 2004. The program's final phase set a stretch goal of demonstrating 50% Brake Thermal Efficiency from a heavy duty diesel engine system capable of meeting 2010 U.S. EPA legislated emissions requirements. Cummins chose to pursue this goal through further combustion development and refinement of the Cooled EGR system architecture and also applied a Rankine cycle Waste Heat Recovery technique to convert otherwise wasted thermal energy to useful power. The engine and heat recovery system was demonstrated to achieve 50% Brake Thermal Efficiency while operating at a torque peak condition in second quarter, 2006. The 50% efficient engine

  13. Macromolecular diffractive imaging using imperfect crystals.

    PubMed

    Ayyer, Kartik; Yefanov, Oleksandr M; Oberthür, Dominik; Roy-Chowdhury, Shatabdi; Galli, Lorenzo; Mariani, Valerio; Basu, Shibom; Coe, Jesse; Conrad, Chelsie E; Fromme, Raimund; Schaffer, Alexander; Dörner, Katerina; James, Daniel; Kupitz, Christopher; Metz, Markus; Nelson, Garrett; Xavier, Paulraj Lourdu; Beyerlein, Kenneth R; Schmidt, Marius; Sarrou, Iosifina; Spence, John C H; Weierstall, Uwe; White, Thomas A; Yang, Jay-How; Zhao, Yun; Liang, Mengning; Aquila, Andrew; Hunter, Mark S; Robinson, Joseph S; Koglin, Jason E; Boutet, Sébastien; Fromme, Petra; Barty, Anton; Chapman, Henry N

    2016-02-11

    The three-dimensional structures of macromolecules and their complexes are mainly elucidated by X-ray protein crystallography. A major limitation of this method is access to high-quality crystals, which is necessary to ensure X-ray diffraction extends to sufficiently large scattering angles and hence yields information of sufficiently high resolution with which to solve the crystal structure. The observation that crystals with reduced unit-cell volumes and tighter macromolecular packing often produce higher-resolution Bragg peaks suggests that crystallographic resolution for some macromolecules may be limited not by their heterogeneity, but by a deviation of strict positional ordering of the crystalline lattice. Such displacements of molecules from the ideal lattice give rise to a continuous diffraction pattern that is equal to the incoherent sum of diffraction from rigid individual molecular complexes aligned along several discrete crystallographic orientations and that, consequently, contains more information than Bragg peaks alone. Although such continuous diffraction patterns have long been observed--and are of interest as a source of information about the dynamics of proteins--they have not been used for structure determination. Here we show for crystals of the integral membrane protein complex photosystem II that lattice disorder increases the information content and the resolution of the diffraction pattern well beyond the 4.5-ångström limit of measurable Bragg peaks, which allows us to phase the pattern directly. Using the molecular envelope conventionally determined at 4.5 ångströms as a constraint, we obtain a static image of the photosystem II dimer at a resolution of 3.5 ångströms. This result shows that continuous diffraction can be used to overcome what have long been supposed to be the resolution limits of macromolecular crystallography, using a method that exploits commonly encountered imperfect crystals and enables model-free phasing. PMID

  14. Macromolecular diffractive imaging using imperfect crystals

    PubMed Central

    Ayyer, Kartik; Yefanov, Oleksandr; Oberthür, Dominik; Roy-Chowdhury, Shatabdi; Galli, Lorenzo; Mariani, Valerio; Basu, Shibom; Coe, Jesse; Conrad, Chelsie E.; Fromme, Raimund; Schaffer, Alexander; Dörner, Katerina; James, Daniel; Kupitz, Christopher; Metz, Markus; Nelson, Garrett; Lourdu Xavier, Paulraj; Beyerlein, Kenneth R.; Schmidt, Marius; Sarrou, Iosifina; Spence, John C. H.; Weierstall, Uwe; White, Thomas A.; Yang, Jay-How; Zhao, Yun; Liang, Mengning; Aquila, Andrew; Hunter, Mark S.; Robinson, Joseph S.; Koglin, Jason E.; Boutet, Sébastien; Fromme, Petra; Barty, Anton; Chapman, Henry N.

    2016-01-01

    The three-dimensional structures of macromolecules and their complexes are predominantly elucidated by X-ray protein crystallography. A major limitation is access to high-quality crystals, to ensure X-ray diffraction extends to sufficiently large scattering angles and hence yields sufficiently high-resolution information that the crystal structure can be solved. The observation that crystals with shrunken unit-cell volumes and tighter macromolecular packing often produce higher-resolution Bragg peaks1,2 hints that crystallographic resolution for some macromolecules may be limited not by their heterogeneity but rather by a deviation of strict positional ordering of the crystalline lattice. Such displacements of molecules from the ideal lattice give rise to a continuous diffraction pattern, equal to the incoherent sum of diffraction from rigid single molecular complexes aligned along several discrete crystallographic orientations and hence with an increased information content3. Although such continuous diffraction patterns have long been observed—and are of interest as a source of information about the dynamics of proteins4 —they have not been used for structure determination. Here we show for crystals of the integral membrane protein complex photosystem II that lattice disorder increases the information content and the resolution of the diffraction pattern well beyond the 4.5 Å limit of measurable Bragg peaks, which allows us to directly phase5 the pattern. With the molecular envelope conventionally determined at 4.5 Å as a constraint, we then obtain a static image of the photosystem II dimer at 3.5 Å resolution. This result shows that continuous diffraction can be used to overcome long-supposed resolution limits of macromolecular crystallography, with a method that puts great value in commonly encountered imperfect crystals and opens up the possibility for model-free phasing6,7. PMID:26863980

  15. Macromolecular diffractive imaging using imperfect crystals

    NASA Astrophysics Data System (ADS)

    Ayyer, Kartik; Yefanov, Oleksandr M.; Oberthür, Dominik; Roy-Chowdhury, Shatabdi; Galli, Lorenzo; Mariani, Valerio; Basu, Shibom; Coe, Jesse; Conrad, Chelsie E.; Fromme, Raimund; Schaffer, Alexander; Dörner, Katerina; James, Daniel; Kupitz, Christopher; Metz, Markus; Nelson, Garrett; Xavier, Paulraj Lourdu; Beyerlein, Kenneth R.; Schmidt, Marius; Sarrou, Iosifina; Spence, John C. H.; Weierstall, Uwe; White, Thomas A.; Yang, Jay-How; Zhao, Yun; Liang, Mengning; Aquila, Andrew; Hunter, Mark S.; Robinson, Joseph S.; Koglin, Jason E.; Boutet, Sébastien; Fromme, Petra; Barty, Anton; Chapman, Henry N.

    2016-02-01

    The three-dimensional structures of macromolecules and their complexes are mainly elucidated by X-ray protein crystallography. A major limitation of this method is access to high-quality crystals, which is necessary to ensure X-ray diffraction extends to sufficiently large scattering angles and hence yields information of sufficiently high resolution with which to solve the crystal structure. The observation that crystals with reduced unit-cell volumes and tighter macromolecular packing often produce higher-resolution Bragg peaks suggests that crystallographic resolution for some macromolecules may be limited not by their heterogeneity, but by a deviation of strict positional ordering of the crystalline lattice. Such displacements of molecules from the ideal lattice give rise to a continuous diffraction pattern that is equal to the incoherent sum of diffraction from rigid individual molecular complexes aligned along several discrete crystallographic orientations and that, consequently, contains more information than Bragg peaks alone. Although such continuous diffraction patterns have long been observed—and are of interest as a source of information about the dynamics of proteins—they have not been used for structure determination. Here we show for crystals of the integral membrane protein complex photosystem II that lattice disorder increases the information content and the resolution of the diffraction pattern well beyond the 4.5-ångström limit of measurable Bragg peaks, which allows us to phase the pattern directly. Using the molecular envelope conventionally determined at 4.5 ångströms as a constraint, we obtain a static image of the photosystem II dimer at a resolution of 3.5 ångströms. This result shows that continuous diffraction can be used to overcome what have long been supposed to be the resolution limits of macromolecular crystallography, using a method that exploits commonly encountered imperfect crystals and enables model-free phasing.

  16. QCD subgroup on diffractive and forward physics

    SciTech Connect

    Albrow, M.G.; Baker, W.; Bhatti, A.

    1997-09-01

    Over the last few years, there has been a resurgence of interest in small-x or diffractive physics. This has been due to the realization that perturbative QCD techniques may be applicable to what was previously thought of as a non-perturbative problem and to the opening up of new energy regimes at HERA and the Tevatron collider. The goal is to understand the pomeron, and hence the behavior of total cross sections, elastic scattering and diffractive excitation, in terms of the underlying theory, QCD. This paper is divided into experiments of hadron-hadron colliders and electron-proton colliders.

  17. Coherent diffractive imaging of single layer microspheres

    SciTech Connect

    Dinh, Khuong Ba Le, Hoang Vu; Van Vuong, Cuong; Hannaford, Peter; Van Dao, Lap; Ong, Adabelle X. P.; Henderson, Clare A.; Smith, Trevor A.

    2015-04-28

    We report the extreme ultraviolet (XUV) coherent diffractive imaging of silica/polymer micro-particle samples illuminated by a table-top high harmonic generation source at the wavelength of 30 nm. We achieve images constructed from diffraction patterns acquired with 13 μm × 13 μm samples comprising a sparse monolayer of spherical silica and polymer micro-particles. Successful reconstructed image of an aperiodic sample using this HHG source will open the path to the realization of a compact soft x-ray microscope to investigate other complex absorbing samples.

  18. Anomalous Diffraction in Cold Magnetized Plasma

    NASA Astrophysics Data System (ADS)

    Abelson, Z.; Gad, R.; Bar-Ad, S.; Fisher, A.

    2015-10-01

    Cold magnetized plasma possesses an anisotropic permittivity tensor with a unique dispersion relation that for adequate electron density and magnetic field results in anomalous diffraction of a right-hand circularly polarized beam. In this work, we demonstrate experimentally anomalous diffraction of a microwave beam in plasma. Additionally, decreasing the electron density enables observation of the transition of the material from a hyperbolic to a standard material. Manipulation of the control parameters will enable plasma to serve as a reconfigurable metamaterial-like medium.

  19. Diffraction of entangled particles by light gratings

    NASA Astrophysics Data System (ADS)

    Sancho, Pedro

    2015-04-01

    We analyze the diffraction regime of the Kapitza-Dirac effect for particles entangled in momentum. The detection patterns show two-particle interferences. In the single-mode case we identify a discontinuity in the set of joint detection probabilities, associated with the disconnected character of the space of non-separable states. For Gaussian multi-mode states we derive the diffraction patterns, providing an example of the dependence of the light-matter interaction on entanglement. When the particles are identical, we can explore the relation between exchange and entanglement effects. We find a complementary behavior between overlapping and Schmidt's number. In particular, symmetric entanglement can cancel the exchange effects.

  20. Light-scattering theory of diffraction.

    PubMed

    Guo, Wei

    2010-03-01

    Since diffraction is a scattering process in principle, light propagation through one aperture in a screen is discussed in the light-scattering theory. Through specific calculation, the expression of the electric field observed at an observation point is obtained and is used not only to explain why Kirchhoff's diffraction theory is a good approximation when the screen is both opaque and sufficiently thin but also to demonstrate that the mathematical and physical problems faced by Kirchhoff's theory are avoided in the light-scattering theory. PMID:20208939

  1. Diffraction by dual-period gratings.

    PubMed

    Skigin, Diana C; Depine, Ricardo A

    2007-03-20

    The dynamical characteristics of dual-period perfectly conducting gratings are explored. Gratings with several grooves (reflection) or slits (transmission) within each period are considered. A scalar approach is proposed to derive the general characteristics of the diffracted response. It was found that compound gratings can be designed to cancel as well as to intensify a given diffraction order. These preliminary estimations for finite gratings are validated by numerical examples for infinitely periodic reflection and transmission gratings with finite thickness, performed using an extension of the rigorous modal method to compound gratings, for both polarization cases. PMID:17334426

  2. Single Particle X-ray Diffractive Imaging

    SciTech Connect

    Bogan, M J; Benner, W H; Boutet, S; Rohner, U; Frank, M; Seibert, M; Maia, F; Barty, A; Bajt, S; Riot, V; Woods, B; Marchesini, S; Hau-Riege, S P; Svenda, M; Marklund, E; Spiller, E; Hajdu, J; Chapman, H N

    2007-10-01

    In nanotechnology, strategies for the creation and manipulation of nanoparticles in the gas phase are critically important for surface modification and substrate-free characterization. Recent coherent diffractive imaging with intense femtosecond X-ray pulses has verified the capability of single-shot imaging of nanoscale objects at sub-optical resolutions beyond the radiation-induced damage threshold. By intercepting electrospray-generated particles with a single 15 femtosecond soft-X-ray pulse, we demonstrate diffractive imaging of a nanoscale specimen in free flight for the first time, an important step toward imaging uncrystallized biomolecules.

  3. Anomalous Diffraction in Cold Magnetized Plasma.

    PubMed

    Abelson, Z; Gad, R; Bar-Ad, S; Fisher, A

    2015-10-01

    Cold magnetized plasma possesses an anisotropic permittivity tensor with a unique dispersion relation that for adequate electron density and magnetic field results in anomalous diffraction of a right-hand circularly polarized beam. In this work, we demonstrate experimentally anomalous diffraction of a microwave beam in plasma. Additionally, decreasing the electron density enables observation of the transition of the material from a hyperbolic to a standard material. Manipulation of the control parameters will enable plasma to serve as a reconfigurable metamaterial-like medium. PMID:26551813

  4. Explanation and observability of diffraction in time

    SciTech Connect

    Torrontegui, E.; Muga, J. G.; Munoz, J.; Ban, Yue

    2011-04-15

    Diffraction in time (DIT) is a fundamental phenomenon in quantum dynamics due to time-dependent obstacles and slits. It is formally analogous to diffraction of light, and is expected to play an increasing role in the design of coherent matter wave sources, as in the atom laser, to analyze time-of-flight information and emission from ultrafast pulsed excitations, and in applications of coherent matter waves in integrated atom-optical circuits. We demonstrate that DIT emerges robustly in quantum waves emitted by an exponentially decaying source and provide a simple explanation of the phenomenon, as an interference of two characteristic velocities. This allows for its controllability and optimization.

  5. Wave diffraction by a cosmic string

    NASA Astrophysics Data System (ADS)

    Fernández-Núñez, Isabel; Bulashenko, Oleg

    2016-08-01

    We show that if a cosmic string exists, it may be identified through characteristic diffraction pattern in the energy spectrum of the observed signal. In particular, if the string is on the line of sight, the wave field is shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's geometrical theory of diffraction, which allows to explain wave effects in conical spacetime of a cosmic string in terms of interference of four characteristic rays. Our results are supposed to be valid for scalar massless waves, including gravitational waves, electromagnetic waves, or even sound in case of condensed matter systems with analogous topological defects.

  6. Coherent diffractive imaging: towards achieving atomic resolution.

    PubMed

    Dietze, S H; Shpyrko, O G

    2015-11-01

    The next generation of X-ray sources will feature highly brilliant X-ray beams that will enable the imaging of local nanoscale structures with unprecedented resolution. A general formalism to predict the achievable spatial resolution in coherent diffractive imaging, based solely on diffracted intensities, is provided. The coherent dose necessary to reach atomic resolution depends significantly on the atomic scale structure, where disordered or amorphous materials require roughly three orders of magnitude lower dose compared with the expected scaling of uniform density materials. Additionally, dose reduction for crystalline materials are predicted at certain resolutions based only on their unit-cell dimensions and structure factors. PMID:26524315

  7. Diffraction-Specific Fringe Computation for Electro -

    NASA Astrophysics Data System (ADS)

    Lucente, Mark

    Diffraction-specific fringe computation is a novel system for the generation of holographic fringe patterns for real-time display. This thesis describes the development, implementation, and analysis of diffraction-specific computation, an approach that considers the reconstruction process rather than the interference process in optical holography. The primary goal is to increase the speed of holographic computation for real-time three-dimensional electro-holographic (holovideo) displays. Diffraction-specific fringe computation is based on the discretization of space and spatial frequency in the fringe pattern. Two holographic fringe encoding techniques are developed from diffraction-specific fringe computation and applied to make most efficient use of hologram channel capacity. A "hogel-vector encoding" technique is based on undersampling the fringe spectra. A "fringelet encoding" technique is designed to increase the speed and simplicity of decoding. The analysis of diffraction-specific computation focuses on the trade-offs between compression ratio, image fidelity, and image depth. The decreased image resolution (increased point spread) that is introduced into holographic images due to encoding is imperceptible to the human visual system under certain conditions. A compression ratio of 16 is achieved (using either encoding method) with an acceptably small loss in image resolution. Total computation time is reduced by a factor of over 100 to less than 7.0 seconds per 36-MB holographic fringe using the fringelet encoding method. Diffraction-specific computation more efficiently matches the information content of holographic fringes to the human visual system. Diffraction-specific holographic encoding allows for "visual-bandwidth holography," i.e., holographic imaging that requires a bandwidth commensurate with the usable visual information contained in an image. Diffraction -specific holographic encoding enables the integration of holographic information with other

  8. Autoindexing diffraction images with iMosflm

    SciTech Connect

    Powell, Harold R.; Johnson, Owen; Leslie, Andrew G. W.

    2013-07-01

    The principles of one-dimensional FFT-based autoindexing of diffraction images are described together with practical issues that may arise. A procedure for indexing multiple lattices as implemented in iMosflm is presented. An overview of autoindexing diffraction images based on one-@@dimensional fast Fourier transforms is presented. The implementation of the algorithm in the Mosflm/iMosflm program suite is described with a discussion of practical issues that may arise and ways of assessing the success or failure of the procedure. Recent developments allow indexing of images that show multiple lattices, and several examples demonstrate the success of this approach in real cases.

  9. Measurement of Diffraction Properties of Colloidal Crystals

    NASA Astrophysics Data System (ADS)

    Selan, Nicholas; Blades, Michael; Joy, Midhun; Gilchrist, James; Rotkin, Slava

    Close-packed, self-assembled arrays of micrometer polystyrene or silica spheres are high quality artificial crystals that generate well-defined diffraction patterns in the visible range. Such crystals are explored as possible substrates for deposition of nanomaterials such as graphene. Quasi-monochromatic visible light diffraction microscopy is used to characterize effective refractive index and crystal structure, specifically grain size, orientation, and lattice parameters. These parameters can be used to monitor deformations of the colloidal crystal lattice during transfer of nanomaterials. NSF ECCS-1509786, N.S. acknowledges RET supplement to NSF ECCS-1202398.

  10. Diffraction efficiency sensitivity to oblique incident angle for multilayer diffractive optical elements.

    PubMed

    Yang, Hongfang; Xue, Changxi; Li, Chuang; Wang, Ju; Zhang, Ran

    2016-09-01

    The relationship between diffraction efficiency of multilayer diffractive optical elements (MLDOEs) and arbitrary incident angle was numerically analyzed with the effective area method. The method is based on the shield effect between two elements of MLDOEs; a generalized diffraction efficiency formulation was obtained in a wide range of tilt angles, which overcame the limitations of scalar diffraction theory when the period width of MLDOEs is taken into account. A detailed comparison of the proposed effective area method with the scalar diffraction theory is numerically presented for MLDOEs. The validity of the proposed method is verified by comparison with the rigorous electromagnetic analysis method, especially the finite-difference time-domain method. The analysis results show that the shield effect augments with the increase of the incident angles; the effect of incident angles on MLDOEs with finite period widths is more noticeable than that with large period widths. PMID:27607291

  11. Heavy ion therapy: Bevalac epoch

    SciTech Connect

    Castro, J.R.

    1993-10-01

    An overview of heavy ion therapy at the Bevelac complex (SuperHILac linear accelerator + Bevatron) is given. Treatment planning, clinical results with helium ions on the skull base and uveal melanoma, clinical results with high-LET charged particles, neon radiotherapy of prostate cancer, heavy charged particle irradiation for unfavorable soft tissue sarcoma, preliminary results in heavy charged particle irradiation of bone sarcoma, and irradiation of bile duct carcinoma with charged particles and-or photons are all covered. (GHH)

  12. Heavy quark production and spectroscopy

    SciTech Connect

    Appel, J.A.

    1993-11-01

    This review covers many new experimental results on heavy flavor production and spectroscopy. It also shows some of the increasingly improved theoretical understanding of results in light of basic perturbative QCD and heavy quark symmetry. At the same time, there are some remaining discrepancies among experiments as well as significant missing information on some of the anticipated lowest lying heavy quark states. Most interesting, perhaps, are some clearly measured production effects awaiting full explanation.

  13. Heavy-flavor production overview

    SciTech Connect

    Jeffrey A. Appel

    2003-12-10

    This talk serves as an introduction to the Heavy-Flavor session of the XXXIII International Symposium on Multiparticle Dynamics. A major focus of this session is on the production of heavy quarks. The talks which follow review the latest results on heavy quark production in strong, electromagnetic, and weak interactions, as well as some of the physics of the heavy quarks themselves. This talk emphasizes what we can learn from the production measurements, both about underlying QCD theory and the partonic nature of the hadrons which we see in the laboratory.

  14. Exploring the magnetic phase diagram of dysprosium with neutron diffraction

    NASA Astrophysics Data System (ADS)

    Yu, J.; LeClair, P. R.; Mankey, G. J.; Robertson, J. L.; Crow, M. L.; Tian, W.

    2015-01-01

    With one of the highest intrinsic magnetic moments (10.6 μB/atom ) among the heavy rare-earth elements, dysprosium exhibits a rich magnetic phase diagram, including several modulated magnetic phases. Aided by the Ruderman-Kittel-Kasuya-Yosida interaction, the magnetic modulations propagate coherently over a long range. Neutron diffraction experiments were performed to determine the microscopic magnetic origin of the field induced phases in bulk Dy as a function of temperature, covering regions of the well-known ferromagnetic, helical antiferromagnetic, fan phases, and several possible new phases suggested by previous studies. A short-range ordered fan phase was identified as the intermediate state between ferromagnetism and long-range ordered fan. In a field of 1 T applied along the a axis, the temperature range of a coexisting helix/fan phase was determined. The magnetic phase diagram of Dy was thus refined to include the detailed magnetic origin and the associated phase boundaries. Based on the period of the magnetic modulation and the average magnetization, the evolution of the spin arrangement upon heating was derived quantitatively for the modulated magnetic phases.

  15. The Dynamical Theory of X Ray Diffraction

    ERIC Educational Resources Information Center

    Balchin, A. A.; Whitehouse, C. R.

    1974-01-01

    Summarizes the Darwin theory of x-ray diffraction in thin crystals or crystals with a mosaic texture and its modified application to crystals with three-dimensional electrostatic dipoles. Indicates that the dynamical theory is brought into its present relevance by the improvement of single crystal growth techniques. (CC)

  16. Idealized powder diffraction patterns for cellulose polymorphs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cellulose samples are routinely analyzed by X-ray diffraction to determine their crystal type (polymorph) and crystallinity. However, the connection is seldom made between those efforts and the crystal structures of cellulose that have been determined with synchrotron X-radiation and neutron diffrac...

  17. Diffraction from nonperiodic models of cellulose crystals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Powder and fiber diffraction patterns were calculated for model cellulose crystallites with chains 20 glucose units long. Model sizes ranged from four chains to 169 chains, based on cellulose I' coordinates, and were subjected to various combinations of energy minimization and molecular dynamics (M...

  18. Diffraction gratings used as identifying markers

    DOEpatents

    Deason, Vance A.; Ward, Michael B.

    1991-01-01

    A finely detailed defraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the defraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating.

  19. Programmable diffractive lens for ophthalmic application

    NASA Astrophysics Data System (ADS)

    Millán, María S.; Pérez-Cabré, Elisabet; Romero, Lenny A.; Ramírez, Natalia

    2014-06-01

    Pixelated liquid crystal displays have been widely used as spatial light modulators to implement programmable diffractive optical elements, particularly diffractive lenses. Many different applications of such components have been developed in information optics and optical processors that take advantage of their properties of great flexibility, easy and fast refreshment, and multiplexing capability in comparison with equivalent conventional refractive lenses. We explore the application of programmable diffractive lenses displayed on the pixelated screen of a liquid crystal on silicon spatial light modulator to ophthalmic optics. In particular, we consider the use of programmable diffractive lenses for the visual compensation of refractive errors (myopia, hypermetropia, astigmatism) and presbyopia. The principles of compensation are described and sketched using geometrical optics and paraxial ray tracing. For the proof of concept, a series of experiments with artificial eye in optical bench are conducted. We analyze the compensation precision in terms of optical power and compare the results with those obtained by means of conventional ophthalmic lenses. Practical considerations oriented to feasible applications are provided.

  20. Diffraction from fractal grating Cantor sets

    NASA Astrophysics Data System (ADS)

    Golmankhaneh, Alireza K.; Baleanu, D.

    2016-08-01

    In this paper, we have generalized the Fα-calculus by suggesting Fourier and Laplace transformations of the function with support of the fractals set which are the subset of the real line. Using this generalization, we have found the diffraction fringes from the fractal grating Cantor sets.

  1. Optical diffractive elements for medical applications

    NASA Astrophysics Data System (ADS)

    Mikula, Grzegorz; Kolodziejczyk, Andrzej; Makowski, Michal; Sypek, Maciej

    2005-09-01

    We present a class of diffractive elements that can be used in medical applications. We describe their physical properties, in particular the point spread functions and modulation transfer functions. Our analyses consist of the detailed numerical simulations. The obtained results correspond to the different setup parameters and confirm usefulness of such structures in medical aspect, especially in presbyopia treatment.

  2. Pulsed neutron diffraction in special sample environments

    SciTech Connect

    Jorgensen, J.D.

    1987-05-01

    Neutron diffraction is a powerful tool for structural studies of samples in special sample environments because of the high penetrating power of neutrons compared to x rays. The neutrons readily penetrate special sample containers, heat shields, pressure vessels, etc., making it unnecessary in most cases to compromise the effectiveness of the sample environment system by providing windows for the incident and scattered neutrons. Pulsed neutrons obtained from an accelerator-based pulsed neutron source offer the additional advantage that many diffraction experiments can be done at a single, fixed scattering angle by the time-of-flight technique. In the fixed-angle scattering geometry, shielding and collimation can be optimized in order to access the largest possible sample volume with neutrons while completely avoiding scattering from the surrounding sample vessel. Thus, the data are free from unwanted background scattering. In this paper, the basic principles of neutron diffraction in special sample environments are discussed and examples of apparatus used for neutron diffraction measurements at low temperature, high temperature, and high pressure are presented. 36 refs., 15 figs., 3 tabs.

  3. Single Hit Energy-resolved Laue Diffraction

    SciTech Connect

    Patel, Shamim; Suggit, Matthew J.; Stubley, Paul G.; Ciricosta, Orlando; Wark, Justin S.; Higginbotham, Andrew; Hawreliak, James A.; Collins, Gilbert W.; Eggert, Jon H.; Comley, Andrew J.; Foster, John M.

    2015-05-15

    In situ white light Laue diffraction has been successfully used to interrogate the structure of single crystal materials undergoing rapid (nanosecond) dynamic compression up to megabar pressures. However, information on strain state accessible via this technique is limited, reducing its applicability for a range of applications. We present an extension to the existing Laue diffraction platform in which we record the photon energy of a subset of diffraction peaks. This allows for a measurement of the longitudinal and transverse strains in situ during compression. Consequently, we demonstrate measurement of volumetric compression of the unit cell, in addition to the limited aspect ratio information accessible in conventional white light Laue. We present preliminary results for silicon, where only an elastic strain is observed. VISAR measurements show the presence of a two wave structure and measurements show that material downstream of the second wave does not contribute to the observed diffraction peaks, supporting the idea that this material may be highly disordered, or has undergone large scale rotation.

  4. Soft QCD and Diffractive Physics at Lhc

    NASA Astrophysics Data System (ADS)

    Scapparone, Eugenio

    2012-12-01

    After a short introduction on the importance of the soft and of the diffractive studies in the understanding of minimum bias events, the main results obtained at LHC are discussed. This overview includes identified particle and inclusive measurements, minimum bias and underlying events, all of them shedding light on the soft process production mechanisms. The results of the inelastic cross-section measurements obtained by the LHC experiments and their compatibility are discussed together with the models used to extrapolate the data at low diffractive masses. A review of the most recent diffraction results is presented, showing the different approaches used by the LHC experiments, relying on different experimental techniques. The combination of the results obtained by ALICE, ATLAS, CMS, LHCb and TOTEM provides a wide sample of informations, covering an unprecedented pseudorapidity range. A detailed comparison between the obtained results is shown, followed by a critical discussion on the still existing discrepancies between the experimental data and the Monte Carlo used at LHC to simulate soft and diffractive physics.

  5. A Simple Experiment on Fresnel Diffraction

    ERIC Educational Resources Information Center

    Haskell, Richard E.

    1970-01-01

    Describes an experiment in which the Fresnel diffraction pattern of a single slit can be displayed directly on an oscilloscope. The experiment requires a minimum amount of equipment and space. Results of the experiment are presented and compared with theoretical calculations carried out by a digital computer. (LC)

  6. Sub-diffraction limit resolution in microscopy

    NASA Technical Reports Server (NTRS)

    Cheng, Ming (Inventor); Chen, Weinong (Inventor)

    2007-01-01

    A method and apparatus for visualizing sub-micron size particles employs a polarizing microscope wherein a focused beam of polarized light is projected onto a target, and a portion of the illuminating light is blocked from reaching the specimen, whereby to produce a shadow region, and projecting diffracted light from the target onto the shadow region.

  7. Diffraction contrast imaging using virtual apertures.

    PubMed

    Gammer, Christoph; Burak Ozdol, V; Liebscher, Christian H; Minor, Andrew M

    2015-08-01

    Two methods on how to obtain the full diffraction information from a sample region and the associated reconstruction of images or diffraction patterns using virtual apertures are demonstrated. In a STEM-based approach, diffraction patterns are recorded for each beam position using a small probe convergence angle. Similarly, a tilt series of TEM dark-field images is acquired. The resulting datasets allow the reconstruction of either electron diffraction patterns, or bright-, dark- or annular dark-field images using virtual apertures. The experimental procedures of both methods are presented in the paper and are applied to a precipitation strengthened and creep deformed ferritic alloy with a complex microstructure. The reconstructed virtual images are compared with conventional TEM images. The major advantage is that arbitrarily shaped virtual apertures generated with image processing software can be designed without facing any physical limitations. In addition, any virtual detector that is specifically designed according to the underlying crystal structure can be created to optimize image contrast. PMID:25840371

  8. Observation of diffraction caustics for ultrasound

    NASA Astrophysics Data System (ADS)

    Dong, Rui-qi; Adler, Laszlo; Doyle, P. A.

    1983-05-01

    The formation of caustics due to the diffraction of ultrasound is observed by scanning in the shadow region close behind an elliptical obstacle in water. Good agreement is obtained between experiment and the theoretical geometry of the caustic, which is an astroid centered in that shadow region.

  9. Diffractive Pedagogies: Dancing across New Materialist Imaginaries

    ERIC Educational Resources Information Center

    Hickey-Moody, Anna; Palmer, Helen; Sayers, Esther

    2016-01-01

    We theorise an interdisciplinary arts practice university course and consider the forms of educational imaginary challenged by our curriculum. We argue for the disruptive and generative potential of what we call diffractive pedagogy as an example of the type of learning that can take place when materiality and entanglement are considered as vital…

  10. Diffraction Analysis Of Distorted Reflector Antennas

    NASA Technical Reports Server (NTRS)

    Rahmat-Samii, Yahya; Mumford, Jeffrey H.

    1990-01-01

    Effects of systematic distortions of surfaces on radiation patterns predicted. Computer program for Diffraction Analysis of Reflector Antennas Subject to Systematic Distortions predicts performance of reflector antennas subject to sinusoidal, thermal, or gravitational distortions. Provides local interpolation algorithm readily applied to nonregular distribution of data. Developed in UNIVAC FORTRAN 77 for UNIVAC computer.

  11. Diffraction of a baffled dipole - Frequency dependence

    NASA Astrophysics Data System (ADS)

    McInerny, S. A.; Meecham, W. C.; Ngo, T. V.; Liu, S. C.

    1985-05-01

    Experimental results are presented which confirm the diffraction effects predicted by the MacDonald (1915) form of the Green's function for the baffled field in the theory of trailing edge noise. Using this Green's function, the acoustic intensity of noise generated by flow over a trailing edge has been determined to be proportional to the 5th-power of the flow velocity.

  12. X-Ray Diffraction on NIF

    SciTech Connect

    Eggert, J H; Wark, J

    2012-02-15

    The National Ignition Facility (NIF) is currently a 192 beam, 1.6 MJ laser. NIF Ramp-Compression Experiments have already made the relevant exo-planet pressure range from 1 to 50 Mbar accessible. We Proposed to Study Carbon Phases by X-Ray Diffraction on NIF. Just a few years ago, ultra-high pressure phase diagrams for materials were very 'simple'. New experiments and theories point out surprising and decidedly complex behavior at the highest pressures considered. High pressures phases of aluminum are also predicted to be complex. Recent metadynamics survey of carbon proposed a dynamic pathway among multiple phases. We need to develop diagnostics and techniques to explore this new regime of highly compressed matter science. X-Ray Diffraction - Understand the phase diagram/EOS/strength/texture of materials to 10's of Mbar. Strategy and physics goals: (1) Powder diffraction; (2) Begin with diamond; (3) Continue with metals etc.; (4) Explore phase diagrams; (5) Develop liquid diffraction; and (6) Reduce background/improve resolution.

  13. EDITORIAL: Focus on Heavy Ions in Biophysics and Medical Physics FOCUS ON HEAVY IONS IN BIOPHYSICS AND MEDICAL PHYSICS

    NASA Astrophysics Data System (ADS)

    Durante, Marco

    2008-07-01

    include carcinogenesis, late degenerative tissue effects (including damage to the central nervous system), and hereditary effects. For these studies, microbeams represent an essential tool, considering that in space each cell in the human body will not experience more than one heavy-ion traversal. Both NASA and ESA are investing important resources in ground-based space radiation research programs, to reduce risk uncertainty and to develop countermeasures. For both cancer therapy and space radiation protection a better understanding of the effects of energetic heavy ions is needed. Physics should be improved, especially the measurements of nuclear fragmentation cross-sections, and the transport calculations. Biological effects need to be studied in greater detail, and clearly only understanding the mechanisms of heavy-ion induced biological damage will reduce the uncertainty on late effects in humans. This focus issue of New Journal of Physics aims to provide the state-of-the-art of the biophysics of energetic heavy ions and to highlight the areas where more research is urgently needed for therapy and the space program. Focus on Heavy Ions in Biophysics and Medical Physics Contents Heavy ion microprobes: a unique tool for bystander research and other radiobiological applications K O Voss, C Fournier and G Taucher-Scholz Heavy ions light flashes and brain functions: recent observations at accelerators and in spaceflight L Narici Clinical advantages of carbon-ion radiotherapy Hirohiko Tsujii, Tadashi Kamada, Masayuki Baba, Hiroshi Tsuji, Hirotoshi Kato, Shingo Kato, Shigeru Yamada, Shigeo Yasuda, Takeshi Yanagi, Hiroyuki Kato, Ryusuke Hara, Naotaka Yamamoto and Junetsu Mizoe Heavy-ion effects: from track structure to DNA and chromosome damage F Ballarini, D Alloni, A Facoetti and A Ottolenghi Shielding experiments with high-energy heavy ions for spaceflight applications C Zeitlin, S Guetersloh, L Heilbronn, J Miller, N Elkhayari, A Empl, M LeBourgeois, B W Mayes, L Pinsky

  14. Rheological properties of heavy oils and heavy oil emulsions

    SciTech Connect

    Khan, M.R.

    1996-06-01

    In this study, the author investigated the effects of a number of process variables such as shear rate, measurement temperature, pressure, the influence of pretreatment, and the role of various amounts of added water on the rheology of the resulting heavy oil or the emulsion. Rheological properties of heavy oils and the corresponding emulsions are important from transportation and processing standpoints.

  15. X-ray diffraction measurement of residual stresses in thick, multi-pass steel weldments

    SciTech Connect

    Ruud, C.O.; Di Mascio, P.S.; Pangborn, R.N.; Snoha, D.J.

    1985-05-01

    A unique X-ray diffraction instrument for residual stress measurement has been developed that provides for speed, ease of measurement, accuracy, and economy of surface stress measurement. Application of this instrument with a material removal technique, e.g., electropolishing, has facilitated detailed, high resolution studies of three-dimensional stress fields. This paper describes the instrumentation and techniques applied to conduct the residual stress measurement and presents maps of the residual stress data obtained for the surfaces of a heavy 21/4 Cr 1 Mo steel plate weldment.

  16. Transmissive Diffractive Optical Element Solar Concentrators

    NASA Technical Reports Server (NTRS)

    Baron, Richard; Moynihan, Philip; Price, Douglas

    2008-01-01

    Solar-thermal-radiation concentrators in the form of transmissive diffractive optical elements (DOEs) have been proposed as alternatives to mirror-type solar concentrators now in use. In comparison with functionally equivalent mirror-type solar concentrators, the transmissive, diffractive solar concentrators would weigh and cost less, and would be subject to relaxed mechanical tolerances. A DOE concentrator would be made from a thin, flat disk or membrane of a transmissive material having a suitable index of refraction. By virtue of its thinness, the DOE concentrator would have an areal mass density significantly less than that of a functionally equivalent conventional mirror. The DOE concentrator would have a relatively wide aperture--characterized by a focal-length/aperture-diameter ratio ('f number') on the order of 1. A kinoform (a surface-relief phase hologram) of high diffractive order would be microfabricated onto one face of the disk. The kinoform (see figure) would be designed to both diffract and refract incident solar radiation onto a desired focal region, without concern for forming an image of the Sun. The high diffractive order of this kinoform (in contradistinction to the low diffractive orders of some other kinoforms) would be necessary to obtain the desired f number of 1, which, in turn, would be necessary for obtaining a desired concentration ratio of 2,500 or greater. The design process of optimizing the concentration ratio of a proposed DOE solar concentrator includes computing convolutions of the optical bandwidth of the Sun with the optical transmission of the diffractive medium. Because, as in the cases of other non-imaging, light-concentrating optics, image quality is not a design requirement, the process also includes trading image quality against concentration ratio. A baseline design for one example calls for an aperture diameter of 1 m. This baseline design would be scalable to a diameter as large as 10 m, or to a smaller diameter for a

  17. The early development of neutron diffraction: science in the wings of the Manhattan Project

    PubMed Central

    Mason, T. E.; Gawne, T. J.; Nagler, S. E.; Nestor, M. B.; Carpenter, J. M.

    2013-01-01

    Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan Project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurement of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor. Subsequent work by Wollan and Clifford G. Shull, who joined Wollan’s group at Oak Ridge in 1946, laid the foundations for widespread application of neutron diffraction as an important research tool. PMID:23250059

  18. Diffractive Physics at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Revol, Jean-Pierre

    2011-07-01

    After a short introduction on diffraction, I briefly review the framework used to describe non-perturbative QCD phenomena in hadron-hadron interactions. Then I explain why diffractive processes cannot be ignored at LHC and how ALICE, ATLAS, CMS, LHCb and TOTEM study diffraction, with emphasis on how inclusive particle production measurements are normalised to non-single diffractive and inelastic event classes.

  19. Single electrons from heavy-flavor decays in collisions at.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2006-01-27

    The invariant differential cross section for inclusive electron production in p+p collisions at [FORMULA: SEE TEXT] has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over the transverse momentum range 0.4central rapidity region ([FORMULA: SEE TEXT]). The contribution to the inclusive electron spectrum from semileptonic decays of hadrons carrying heavy flavor, i.e., charm quarks or, at high , bottom quarks, is determined via three independent methods. The resulting electron spectrum from heavy-flavor decays is compared to recent leading and next-to-leading order perturbative QCD calculations. The total cross section of charm quark-antiquark pair production is determined to be [FORMULA: SEE TEXT]. PMID:16486684

  20. Diffractive interference optical analyzer (DiOPTER)

    NASA Astrophysics Data System (ADS)

    Sasikumar, Harish; Prasad, Vishnu; Pal, Parama; Varma, Manoj M.

    2016-03-01

    This report demonstrates a method for high-resolution refractometric measurements using, what we have termed as, a Diffractive Interference Optical Analyzer (DiOpter). The setup consists of a laser, polarizer, a transparent diffraction grating and Si-photodetectors. The sensor is based on the differential response of diffracted orders to bulk refractive index changes. In these setups, the differential read-out of the diffracted orders suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6x10-7 RIU was achieved in glass. This work focuses on devices with integrated sample well, made on low-cost PDMS. As the detection methodology is experimentally straightforward, it can be used across a wide array of applications, ranging from detecting changes in surface adsorbates via binding reactions to estimating refractive index (and hence concentration) variations in bulk samples. An exciting prospect of this technique is the potential integration of this device to smartphones using a simple interface based on transmission mode configuration. In a transmission configuration, we were able to achieve an LoD of 4x10-4 RIU which is sufficient to explore several applications in food quality testing and related fields. We are envisioning the future of this platform as a personal handheld optical analyzer for applications ranging from environmental sensing to healthcare and quality testing of food products.

  1. Diffractive Higgs boson photoproduction in ultraperipheral collisions at LHC

    SciTech Connect

    Gay Ducati, M. B.; Silveira, G. G.

    2010-10-01

    A new production mechanism for the standard model Higgs boson in ultraperipheral collisions at the LHC, which allows central exclusive diffractive production by double pomeron exchange in photon-proton processes, is presented. The Higgs boson is centrally produced by gluon fusion with two large rapidity gaps emerging in the final state, being the main experimental signature for this process. As already studied for Pomeron-Pomeron and two-photon processes, the Higgs boson photoproduction is studied within this new mechanism in proton-proton (pp) and proton-nucleus (pA) collisions, where each system has a different dynamics to be taken into account. As a result, this mechanism predicts a production cross section for pp collisions of about 1.8 fb, which is similar to that obtained in Pomeron-Pomeron processes. Besides, in pPb collisions the cross sections have increased to about 0.6 pb, being comparable with the results of two-photon processes in pAu collisions. Therefore, as the rapidity gap survival probability is an open question in high-energy physics, an analysis for different values of this probability shows how competitive the mechanisms are in the LHC kinematical regime.

  2. Phase-shifting point diffraction interferometer phase grating designs

    DOEpatents

    Naulleau, Patrick

    2001-01-01

    Diffraction phase gratings are employed in phase-shifting point diffraction interferometers to improve the interferometric fringe contrast. The diffraction phase grating diffracts a zeroth-order diffraction of light at a first power level to the test-beam window of a mask that is positioned at the image plane and a first-order diffraction at a second power to the reference-beam pinhole. The diffraction phase grating is preferably selected to yield a desired ratio of the first power level to second power level.

  3. Diffraction and imaging study of imperfections of crystallized lysozyme with coherent X-rays

    NASA Technical Reports Server (NTRS)

    Hu, Z. W.; Chu, Y. S.; Lai, B.; Thomas, B. R.; Chernov, A. A.

    2004-01-01

    Phase-contrast X-ray diffraction imaging and high-angular-resolution diffraction combined with phase-contrast radiographic imaging were employed to characterize defects and perfection of a uniformly grown tetragonal lysozyme crystal in the symmetric Laue case. The full-width at half-maximum (FWHM) of a 4 4 0 rocking curve measured from the original crystal was approximately 16.7 arcsec and imperfections including line defects, inclusions and other microdefects were observed in the diffraction images of the crystal. The observed line defects carry distinct dislocation features running approximately along the <1 1 0> growth front and have been found to originate mostly in a central growth area and occasionally in outer growth regions. Inclusions of impurities or formations of foreign particles in the central growth region are resolved in the images with high sensitivity to defects. Slow dehydration led to the broadening of a fairly symmetric 4 4 0 rocking curve by a factor of approximately 2.6, which was primarily attributed to the dehydration-induced microscopic effects that are clearly shown in X-ray diffraction images. The details of the observed defects and the significant change in the revealed microstructures with drying provide insight into the nature of imperfections, nucleation and growth, and the properties of protein crystals.

  4. Heavy ion measurement on LDEF

    NASA Technical Reports Server (NTRS)

    Beaujean, R.; Jonathal, D.; Enge, W.

    1992-01-01

    A stack of CR-39 and Kodak CN track detectors was exposed on the NASA satellite LDEF and recovered after almost six years in space. The quick look analysis yielded heavy ion tracks on a background of low energy secondaries from proton interaction. The detected heavy ions show a steep energy spectrum which indicates a radiation belt origin.

  5. HEAVY METAL PUMPS IN PLANTS

    EPA Science Inventory

    Plants have been proposed as a bioremediation tool to help remove toxic heavy metals from contaminated land and water. However, little is known about how plants take up heavy metals from the soil and transport them to different parts of the plant. An important long term goal is t...

  6. Heavy Equipment Mechanic Program Guide.

    ERIC Educational Resources Information Center

    Georgia Univ., Athens. Dept. of Vocational Education.

    Designed to train an entry-level mechanic, this heavy equipment mechanic program guide presents the standard curriculum for technical institutes in Georgia. The curriculum addresses the minimum competencies for a heavy equipment mechanic program. The general information section contains the following: purpose and objectives; program description,…

  7. SULFIDE PRECIPITATION OF HEAVY METALS

    EPA Science Inventory

    The research program was initiated with the objective of evaluating a new process, the sulfide precipitation of heavy metals from industrial wastewaters. The process was expected to effect a more complete removal of heavy metals than conventional lime processing because of the mu...

  8. Heavy Equipment Mechanic. Instructor Edition.

    ERIC Educational Resources Information Center

    Hendrix, Laborn J.; And Others

    This manual is intended to assist heavy equipment instructors in teaching the latest concepts and functions of heavy equipment. It includes 7 sections and 27 instructional units. Sections (and units) are: orientation (shop safety and first aid, hand tools and miscellaneous tools, measuring, basic rigging and hoisting), engines (basic engine…

  9. HEAVY ION LINEAR ACCELERATOR

    DOEpatents

    Van Atta, C.M.; Beringer, R.; Smith, L.

    1959-01-01

    A linear accelerator of heavy ions is described. The basic contributions of the invention consist of a method and apparatus for obtaining high energy particles of an element with an increased charge-to-mass ratio. The method comprises the steps of ionizing the atoms of an element, accelerating the resultant ions to an energy substantially equal to one Mev per nucleon, stripping orbital electrons from the accelerated ions by passing the ions through a curtain of elemental vapor disposed transversely of the path of the ions to provide a second charge-to-mass ratio, and finally accelerating the resultant stripped ions to a final energy of at least ten Mev per nucleon.

  10. Heavy ion beam probing

    SciTech Connect

    Hickok, R L

    1980-07-01

    This report consists of the notes distributed to the participants at the IEEE Mini-Course on Modern Plasma Diagnostics that was held in Madison, Wisconsin in May 1980. It presents an overview of Heavy Ion Beam Probing that briefly describes the principles and discuss the types of measurements that can be made. The problems associated with implementing beam probes are noted, possible variations are described, estimated costs of present day systems, and the scaling requirements for large plasma devices are presented. The final chapter illustrates typical results that have been obtained on a variety of plasma devices. No detailed calculations are included in the report, but a list of references that will provide more detailed information is included.

  11. Heavy flavor production

    SciTech Connect

    Berger, E.L.

    1988-06-10

    Predictions are presented of total cross sections for charm and bottom quark production in /bar p/p, ..pi../sup /minus//p, and pp interactions at fixed target and collider energies. The calculations are done through next-to-leading order in QCD perturbation theory. The sensitivity is explored of results to the choices of renormalization/evolution scale, parton densities, ..lambda../sub QCD/, and heavy flavor masses. Comparisons with available data show that good agreement is obtained for reasonable values of charm and bottom quark masses and other parameters. Open issues in the interpretation of results are summarized including the large size of the next-to-leading order contributions, proper definition of the gluon density, the nuclear A dependence of charm cross sections, the role of final state interactions, and higher twist effects. 39 refs., 7 figs., 5 tabs.

  12. Heavy fragment radioactivities

    SciTech Connect

    Price, P.B.

    1987-12-10

    This recently discovered mode of radioactive decay, like alpha decay and spontaneous fission, is believed to involve tunneling through the deformation-energy barrier between a very heavy nucleus and two separated fragments the sum of whose masses is less than the mass of the parent nucleus. In all known cases the heavier of the two fragments is close to doubly magic /sup 208/Pb, and the lighter fragment has even Z. Four isotopes of Ra are known to emit /sup 14/C nuclei; several isotopes of U as well as /sup 230/Th and /sup 231/Pa emit Ne nuclei; and /sup 234/U exhibits four hadronic decay modes: alpha decay, spontaneous fission, Ne decay and Mg decay.

  13. Super-heavy nuclei

    NASA Astrophysics Data System (ADS)

    Hofmann, Sigurd

    2015-11-01

    Scientifically based searches for elements beyond uranium started after the discovery of the neutron. Neutrons captured by uranium nuclei and subsequent {β }- decay, similarly as most of the elements were produced in nature, was the successful method applied. However, as a first result, Hahn and Strassmann discovered nuclear fission indicating a limit for the existence of nuclei at an increasing number of protons. Eventually, the nuclear shell model allowed for a more accurate calculation of binding energies, half-lives and decay modes of the heaviest nuclei. Theoreticians predicted a region of increased stability at proton number Z = 126, later shifted to 114, and neutron number N = 184. These nuclei receive their stability from closed shells for the protons and neutrons. Later, increased stability was also predicted for deformed nuclei at Z = 108 and N = 162. In this review I will report on experimental work performed on research to produce and identify these super-heavy nuclei (SHN). Intensive heavy ion beams, sophisticated target technology, efficient electromagnetic ion separators, and sensitive detector arrays were the prerequisites for discovery of 12 new elements during the last 40 years. The results are described and compared with theoretical predictions and interpretations. An outlook is given on further improvement of experimental facilities which will be needed for exploration of the extension and structure of the island of SHN, in particular for searching for isotopes with longer half-lives predicted to be located in the south east of the island, for new elements, and last not least, for surprises which, naturally, emerge unexpectedly.

  14. Management of heavy drinkers.

    PubMed Central

    Haines, A.; Wiseman, S.

    1992-01-01

    1. The amount of alcohol consumed per capita in the UK has approximately doubled since 1950. 2. One unit of alcohol is equivalent to around 8 g of pure alcohol (half a pint of beer, a single bar measure of spirits or glass of wine). 3. Consumption of above 21 units a week for men and 14 units a week for women carries an increasing risk of alcohol-related damage. Pregnant women are usually advised to abstain. 4. Newly registered patients should be asked if they have consumed any alcohol in the last three months and if so how much they consume in an average week using a quantity frequency scale. 5. In those in whom there is concern about their drinking a systematic 7-day history gives the best estimate of consumption. 6. Heavy drinking should also be considered in a wide range of clinical circumstances, including hypertension, injuries and accidents, marital disharmony and child abuse, dyspepsia, hepatic damage, memory impairment and dementia. Sudden withdrawal may cause fits which may lead to a mistaken diagnosis of epilepsy. 7. Laboratory tests pick up only 30-50% of heavy drinkers but may be useful in monitoring progress and in motivating patients to cut down. 8. It is important to decide whether a patient is dependent on alcohol as dependent drinkers are unlikely to be able to keep their consumption at modest levels. The possibility of psychological and social problems due to alcohol should also be considered. The use of drugs should be explored in dependent drinkers.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1345154

  15. Advances in heavy oil hydroprocessing

    SciTech Connect

    Mendizabal, O.B. )

    1988-06-01

    The world increase in heavy crudes has forced refiners to develop different processes that upgrade the yields and product properties recovered from these crudes. However, some of the optimized and new processes are not able to handle whole heavy crude oils, due to the high viscosity and corrosion of their long and short residues. The different processes for heavy crudes can be classified in two areas: physical (vg. Liquid Extraction) and chemical processes. The catalytic hydrotreating process, which belongs to this last classification, has demonstrated to be an economical upgrading process for heavy crude oil. This paper describes the development by the Mexican Petroleum Institute of the process to hydrotreat maya heavy crude. The effect of the operating conditions, the catalyst ---- development and the technical - economical analysis are presented. The product properties and yields are compared with the results obtained with light crude oil like isthmus.

  16. Results of heavy ion radiotherapy

    SciTech Connect

    Castro, J.R.

    1994-04-01

    The potential of heavy ion therapy for clinical use in cancer therapy stems from the biological parameters of heavy charged particles, and their precise dose localization. Biologically, carbon, neon and other heavy ion beams (up to about silicon) are clinically useful in overcoming the radioresistance of hypoxic tumors, thus increasing biological effectiveness relative to low-LET x-ray or electron beams. Cells irradiated by heavy ions show less variation in cell-cycle related radiosensitivity and decreased repair of radiation injury. The physical parameters of these heavy charged particles allow precise delivery of high radiation doses to tumors while minimizing irradiation of normal tissues. Clinical use requires close interaction between radiation oncologists, medical physicists, accelerator physicists, engineers, computer scientists and radiation biologists.

  17. Managing Inventories of Heavy Actinides

    SciTech Connect

    Wham, Robert M; Patton, Bradley D

    2011-01-01

    The Department of Energy (DOE) has stored a limited inventory of heavy actinides contained in irradiated targets, some partially processed, at the Savannah River Site (SRS) and Oak Ridge National Laboratory (ORNL). The 'heavy actinides' of interest include plutonium, americium, and curium isotopes; specifically 242Pu and 244Pu, 243Am, and 244/246/248Cm. No alternate supplies of these heavy actinides and no other capabilities for producing them are currently available. Some of these heavy actinide materials are important for use as feedstock for producing heavy isotopes and elements needed for research and commercial application. The rare isotope 244Pu is valuable for research, environmental safeguards, and nuclear forensics. Because the production of these heavy actinides was made possible only by the enormous investment of time and money associated with defense production efforts, the remaining inventories of these rare nuclear materials are an important part of the legacy of the Nuclear Weapons Program. Significant unique heavy actinide inventories reside in irradiated Mark-18A and Mark-42 targets at SRS and ORNL, with no plans to separate and store the isotopes for future use. Although the costs of preserving these heavy actinide materials would be considerable, for all practical purposes they are irreplaceable. The effort required to reproduce these heavy actinides today would likely cost billions of dollars and encompass a series of irradiation and chemical separation cycles for at least 50 years; thus, reproduction is virtually impossible. DOE has a limited window of opportunity to recover and preserve these heavy actinides before they are disposed of as waste. A path forward is presented to recover and manage these irreplaceable National Asset materials for future use in research, nuclear forensics, and other potential applications.

  18. Peculiarities of section topograms for the multiple diffraction of X rays

    NASA Astrophysics Data System (ADS)

    Kohn, V. G.; Smirnova, I. A.

    2016-07-01

    The distortion of interference fringes on the section topograms of single crystal due to the multiple diffraction of X rays has been investigated. The cases of the 220 and 400 reflections in a silicon crystal in the form of a plate with a surface oriented normally to the [001] direction are considered both theoretically and experimentally. The same section topogram exhibits five cases of multiple diffraction at small azimuthal angles for the 400 reflection and Mo K α radiation, while the topogram for the 220 reflection demonstrates two cases of multiple diffraction. All these cases correspond to different combinations of reciprocal lattice vectors. Exact theoretical calculations of section topograms for the aforementioned cases of multiple diffraction have been performed for the first time. The section topograms exhibit two different distortion regions. The distortions in the central region of the structure are fairly complex and depend strongly on the azimuthal angle. In the tails of the multiple diffraction region, there is a shift of two-beam interference fringes, which can be observed even with a laboratory X-ray source.

  19. Pulsed photothermal deflection and diffraction effects: numerical modeling based on Fresnel diffraction theory

    NASA Astrophysics Data System (ADS)

    Han, Yue; Wu, Z. L.; Rosenshein, Joseph S.; Thomsen, Marshall; Zhao, Qiang; Moncur, Kent

    1999-12-01

    We present a comprehensive theoretical model suitable for treating the effect of pulsed collinear photothermal deflection spectroscopy (PDS). The work is an extension of the theoretical model previously developed for the mirage effect, which can take into account both photothermal deflection and photothermal diffraction effects based on the Fresnel diffraction theory. With the diffraction model, both the collinear PDS and the photothermal lensing spectroscopy techniques can be treated in a unified manner. The model provides a detailed analysis of the laser-induced optical diffraction effect and can be used to optimize experimental parameters. The modeled results are presented in detail, with an emphasis on the advantages of using a near-field detection scheme for achieving the best sensitivity to local temperature change and better experimental stability against environmental noise.

  20. Diffractive optical element with same diffraction pattern for multicolor light-emitting diodes.

    PubMed

    Chen, Mengzhu; Wang, Qixia; Gu, Huarong; Tan, Qiaofeng

    2016-01-01

    The wavelength-division multiplexing technique can be utilized in visible light communication to increase the channel capacity when a multicolor mixed white LED is used as light source. In such an application, the illumination area of LEDs should be invariant to the incident wavelength, so as to decrease interference within the adjacent regions. Diffractive optical elements (DOEs) can be used in the optical transmitter system to shape the diffraction patterns into polygons. However, traditional DOEs illuminated by a multicolor mixed white LED would result into diffraction patterns with unequal sizes. In this paper, a hybrid algorithm which combines particle swarm optimization with a genetic algorithm is proposed for multicolor oriented DOEs design. A DOE is designed and fabricated for blue and red LEDs, and experimental results show that diffraction patterns with rather good uniformity as well as quasi-equal size for red and blue LEDs are obtained. PMID:26835636

  1. Quantitative measurement of phase variation amplitude of ultrasonic diffraction grating based on diffraction spectral analysis

    SciTech Connect

    Pan, Meiyan Zeng, Yingzhi; Huang, Zuohua

    2014-09-15

    A new method based on diffraction spectral analysis is proposed for the quantitative measurement of the phase variation amplitude of an ultrasonic diffraction grating. For a traveling wave, the phase variation amplitude of the grating depends on the intensity of the zeroth- and first-order diffraction waves. By contrast, for a standing wave, this amplitude depends on the intensity of the zeroth-, first-, and second-order diffraction waves. The proposed method is verified experimentally. The measured phase variation amplitude ranges from 0 to 2π, with a relative error of approximately 5%. A nearly linear relation exists between the phase variation amplitude and driving voltage. Our proposed method can also be applied to ordinary sinusoidal phase grating.

  2. Diffraction Revisited: Position of Diffraction Spots upon Rotation of a Transmission Grating

    ERIC Educational Resources Information Center

    Vollmer, Michael

    2005-01-01

    Diffraction gratings are often used in the laboratory to determine the wavelength of laser light. What happens to the spots on the screen if the grating is rotated in this set-up? The answer is nontrivial and instructive.

  3. Heavy Flavor Physics in Heavy-Ion Collisions with STAR Heavy Flavor Tracker

    NASA Astrophysics Data System (ADS)

    Zhang, Yifei

    2010-02-01

    Heavy quarks are a unique tool to probe the strongly interacting matter created in relativistic heavy-ion collisions at RHIC energies. Due to their large mass, energetic heavy quarks are predicted to lose less energy than light quarks by gluon radiation when they traverse a Quark-Gluon Plasma. In contrast, recent measurements of non-photonic electrons from heavy quark decays at high transverse momentum (pT) show a jet quenching level similar to that of the light hadrons. Heavy quark are produced mainly at early stage in heavy-ion collisions, thus they are proposed to probe the QCD medium and to be sensitive to bulk medium properties. Ultimately, their flow behavior may help establish whether light quarks thermalize. Therefore, topological reconstruction of D-mesons and identification of electrons from charm and bottom decays are crucial to understand the heavy flavor production and their in medium properties. The Heavy Flavor Tracker (HFT) is a micro-vertex detector utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precise measurement of charmed and bottom hadrons. We present a performance study with full detector on the open charm nuclear modification factor, elliptic flow v2 and λc measurement as well as the measurement of bottom mesons via a semi-leptonic decay. )

  4. Periodically distributed objects with quasicrystalline diffraction pattern

    SciTech Connect

    Wolny, Janusz Strzalka, Radoslaw; Kuczera, Pawel

    2015-03-30

    It is possible to construct fully periodically distributed objects with a diffraction pattern identical to the one obtained for quasicrystals. These objects are probability distributions of distances obtained in the statistical approach to aperiodic structures distributed periodically. The diffraction patterns have been derived by using a two-mode Fourier transform—a very powerful method not used in classical crystallography. It is shown that if scaling is present in the structure, this two-mode Fourier transform can be reduced to a regular Fourier transform with appropriately rescaled scattering vectors and added phases. Detailed case studies for model sets 1D Fibonacci chain and 2D Penrose tiling are discussed. Finally, it is shown that crystalline, quasicrystalline, and approximant structures can be treated in the same way.

  5. Photoelectron diffraction and holography: Some new directions

    SciTech Connect

    Fadley, C.S. |

    1993-08-01

    Photoelectron diffraction has by now become a versatile and powerful technique for studying surface structures, with special capabilities for resolving chemical and magnetic states of atoms and deriving direct structural information from both forward scattering along bond directions and back-scattering path length differences. Further fitting experiment to theory can lead to structural accuracies in the {plus_minus}0.03 ){Angstrom} range. Holographic inversions of such diffraction data also show considerable promise for deriving local three-dimensional structures around a given emitter with accuracies of {plus_minus}0.2--0.3 {Angstrom}. Resolving the photoelectron spin in some way and using circularly polarized radiation for excitation provide added dimensions for the study of magnetic systems and chiral experimental geometries. Synchrotron radiation with the highest brightness and energy resolution, as well as variable polarization, is crucial to the full exploitation of these techniques.

  6. Diffractive and exclusive measurements at CDF

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2006-06-01

    Experimental results from the CDF experiment at the Tevatron in p{bar p} collisions at {radical}s = 1.96 TeV are presented on the diffractive structure function at different values of the exchanged momentum transfer squared in the range 0 < Q{sup 2} < 10,000 GeV{sup 2}, on the four-momentum transfer |t| distribution in the region 0 < |t| < 1 GeV{sup 2} for both soft and hard diffractive events up to Q{sup 2} {approx} 4,500 GeV{sup 2}, and on the first experimental evidence of exclusive production in both dijet and diphoton events. A novel technique to align the Roman Pot detectors is also presented.

  7. Amorphouslike diffraction pattern in solid metallic titanium.

    PubMed

    Wang, Y; Fang, Y Z; Kikegawa, T; Lathe, C; Saksl, K; Franz, H; Schneider, J R; Gerward, L; Wu, F M; Liu, J F; Jiang, J Z

    2005-10-01

    Amorphouslike diffraction patterns of solid elemental titanium have been detected under high pressure and high temperature using in situ energy-dispersive x-ray diffraction and a multianvil press. The onset pressure and the temperature of formation of amorphous titanium is found to be close to the alpha-beta-omega triple point in the P-T phase diagram. Amorphous Ti has been found to be thermally stable up to 1250 degrees C for at least 3 min at some pressures. By analyzing the conditions for producing amorphous elemental Zr and Ti, we observed a multi-phase-point amorphization phenomenon for preparing single-element bulk amorphous metals. The results reported may open a new way to preparing single-element bulk amorphous metals with a high thermal stability. PMID:16241734

  8. Phase-shifting point diffraction interferometer

    DOEpatents

    Medecki, Hector

    1998-01-01

    Disclosed is a point diffraction interferometer for evaluating the quality of a test optic. In operation, the point diffraction interferometer includes a source of radiation, the test optic, a beam divider, a reference wave pinhole located at an image plane downstream from the test optic, and a detector for detecting an interference pattern produced between a reference wave emitted by the pinhole and a test wave emitted from the test optic. The beam divider produces separate reference and test beams which focus at different laterally separated positions on the image plane. The reference wave pinhole is placed at a region of high intensity (e.g., the focal point) for the reference beam. This allows reference wave to be produced at a relatively high intensity. Also, the beam divider may include elements for phase shifting one or both of the reference and test beams.

  9. Phase-shifting point diffraction interferometer

    DOEpatents

    Medecki, H.

    1998-11-10

    Disclosed is a point diffraction interferometer for evaluating the quality of a test optic. In operation, the point diffraction interferometer includes a source of radiation, the test optic, a beam divider, a reference wave pinhole located at an image plane downstream from the test optic, and a detector for detecting an interference pattern produced between a reference wave emitted by the pinhole and a test wave emitted from the test optic. The beam divider produces separate reference and test beams which focus at different laterally separated positions on the image plane. The reference wave pinhole is placed at a region of high intensity (e.g., the focal point) for the reference beam. This allows reference wave to be produced at a relatively high intensity. Also, the beam divider may include elements for phase shifting one or both of the reference and test beams. 8 figs.

  10. Metagratings for Diffraction Based, Compact, Holographic Imaging

    NASA Astrophysics Data System (ADS)

    Inampudi, Sandeep; Podolskiy, Viktor; Multiscale Electromagnetics Group Team

    2013-03-01

    Recent developments in semiconductor technology brought to life a new generation of highly-compact visible-frequency cameras. Unfortunately, straight forward extension of this progress to low-frequency domains (such as mid-IR imaging) is impossible since the pixel size at these frequencies is limited by free-space diffraction limit. Here we present an approach to realize highly-compact imaging systems at lower frequencies. Our approach takes advantage of high refractive index of materials commonly utilized in semiconductor detectors of mid-IR radiation, accompanied by metagratings, structures with engineered diffraction properties, to achieve a 10-fold reduction in the pixel size. In contrast to conventional refraction-based imaging, the approach essentially produces a digital hologram - a 2D projection of the 3D optical field, enabling a post-imaging ``refocusing'' of the picture. The perspectives of numerical recovery of the optical field and the stability of such recovery are discussed.

  11. Biomedical Implications of Heavy Metals Induced Imbalances in Redox Systems

    PubMed Central

    Singh, Shweta; Siddiqi, Nikhat J.

    2014-01-01

    Several workers have extensively worked out the metal induced toxicity and have reported the toxic and carcinogenic effects of metals in human and animals. It is well known that these metals play a crucial role in facilitating normal biological functions of cells as well. One of the major mechanisms associated with heavy metal toxicity has been attributed to generation of reactive oxygen and nitrogen species, which develops imbalance between the prooxidant elements and the antioxidants (reducing elements) in the body. In this process, a shift to the former is termed as oxidative stress. The oxidative stress mediated toxicity of heavy metals involves damage primarily to liver (hepatotoxicity), central nervous system (neurotoxicity), DNA (genotoxicity), and kidney (nephrotoxicity) in animals and humans. Heavy metals are reported to impact signaling cascade and associated factors leading to apoptosis. The present review illustrates an account of the current knowledge about the effects of heavy metals (mainly arsenic, lead, mercury, and cadmium) induced oxidative stress as well as the possible remedies of metal(s) toxicity through natural/synthetic antioxidants, which may render their effects by reducing the concentration of toxic metal(s). This paper primarily concerns the clinicopathological and biomedical implications of heavy metals induced oxidative stress and their toxicity management in mammals. PMID:25184144

  12. A neutron diffraction study of amorphous boron

    NASA Astrophysics Data System (ADS)

    Delaplane, R. G.; Lundström, T.; Dahlborg, U.; Howells, W. S.

    1991-07-01

    The structure of amorphous boron has been studied with pulsed neutron diffraction techniques using the ISIS facilities at the Rutherford Appleton Laboratory. The experimental static structure factor S(Q) and radial distribution function support a structural model based on units of B12 icosahedra resembling those found in crystalline β-rhombohedral boron, but with a certain degree of disorder occurring in the linking between these subunits.

  13. Diffraction of Random Noble Means Words

    NASA Astrophysics Data System (ADS)

    Moll, Markus

    2014-09-01

    In this paper, several aspects of the random noble means substitution are studied. Beyond important dynamical facets such as the frequency of subwords and the computation of the topological entropy, the important issue of ergodicity is addressed. From the geometrical point of view, we outline a suitable cut and project setting for associated point sets and present results for the spectral analysis of the diffraction measure.

  14. Diffraction smoothing aperture for an optical beam

    DOEpatents

    Judd, O'Dean P.; Suydam, Bergen R.

    1976-01-01

    The disclosure is directed to an aperture for an optical beam having an irregular periphery or having perturbations imposed upon the periphery to decrease the diffraction effect caused by the beam passing through the aperture. Such apertures are particularly useful with high power solid state laser systems in that they minimize the problem of self-focusing which frequently destroys expensive components in such systems.

  15. Numerical focusing in diffraction phase microscopy

    NASA Astrophysics Data System (ADS)

    Talaikova, N. A.; Grebenyuk, A. A.; Kalyanov, A. L.; Ryabukho, V. P.

    2016-04-01

    Diffraction phase microscopy (DPM) provides the possibility of high-resolution quantitative phase imaging, based on equipment of an optical microscope with a special module working in a common-path off-axis configuration. As an optical microscopy technique, DPM has a limited focus depth, which is the smaller the higher is the objective's numerical aperture. In this paper we present the results of experimental investigation of numerical focusing with the angular spectrum method in DPM.

  16. Optimizing Crystal Volume for Neutron Diffraction Studies

    NASA Technical Reports Server (NTRS)

    Snell, E. H.

    2003-01-01

    For structural studies with neutron diffraction more intense neutron sources, improved sensitivity detector and larger volume crystals are all means by which the science is being advanced to enable studies on a wider range of samples. We have chosen a simplistic approach using a well understood crystallization method, with minimal amounts of sample and using design of experiment techniques to maximize the crystal volume all for minimum effort. Examples of the application are given.

  17. Focusing Diffraction Grating Element with Aberration Control

    NASA Technical Reports Server (NTRS)

    Iazikov, Dmitri; Mossberg, Thomas W.; Greiner, Christoph M.

    2010-01-01

    Diffraction gratings are optical components with regular patterns of grooves, which angularly disperse incoming light by wavelength in a single plane, called dispersion plane. Traditional gratings on flat substrates do not perform wavefront transformation in the plane perpendicular to the dispersion plane. The device proposed here exhibits regular diffraction grating behavior, dispersing light. In addition, it performs wavelength transformation (focusing or defocusing) of diffracted light in a direction perpendicular to the dispersion plane (called sagittal plane). The device is composed of a diffraction grating with the grooves in the form of equidistant arcs. It may be formed by defining a single arc or an arc approximation, then translating it along a certain direction by a distance equal to a multiple of a fixed distance ("grating period") to obtain other groove positions. Such groove layout is nearly impossible to obtain using traditional ruling methods, such as mechanical ruling or holographic scribing, but is trivial for lithographically scribed gratings. Lithographic scribing is the newly developed method first commercially introduced by LightSmyth Technologies, which produces gratings with the highest performance and arbitrary groove shape/spacing for advanced aberration control. Unlike other types of focusing gratings, the grating is formed on a flat substrate. In a plane perpendicular to the substrate and parallel to the translation direction, the period of the grating and, therefore, the projection of its k-vector onto the plane is the same for any location on the grating surface. In that plane, no waveform transformation by the grating k-vector occurs, except of simple redirection.

  18. Autoindexing diffraction images with iMosflm

    PubMed Central

    Powell, Harold R.; Johnson, Owen; Leslie, Andrew G. W.

    2013-01-01

    An overview of autoindexing diffraction images based on one-­dimensional fast Fourier transforms is presented. The implementation of the algorithm in the Mosflm/iMosflm program suite is described with a discussion of practical issues that may arise and ways of assessing the success or failure of the procedure. Recent developments allow indexing of images that show multiple lattices, and several examples demonstrate the success of this approach in real cases. PMID:23793145

  19. Two-particle Kapitza-Dirac diffraction

    SciTech Connect

    Sancho, Pedro

    2010-09-15

    We extend the study of Kapitza-Dirac diffraction to the case of two-particle systems. Due to the exchange effects the shape and visibility of the two-particle detection patterns show important differences for identical and distinguishable particles. We also identify a quantum statistics effect present in momentum space for some values of the initial particle momenta, which is associated with different numbers of photon absorptions compatible with the final momenta.

  20. Diffraction of sound by a smooth ridge

    NASA Technical Reports Server (NTRS)

    Berthelot, Yves H.; Pierce, Allan D.; Kearns, James A.; Main, Geoffrey L.

    1987-01-01

    The propagation of sound over uneven terrain and irregular topography is considered. Laboratory scale experiments were conducted on a 4.88 x 2.44 m plywood bench top with a cylindrical ridge whose radius of curvature is about 2.5 m. Experimental results include the insertion loss on the diffracting surface, and in the penumbra region, at several distances from the apex of the ridge.

  1. Diffraction imaging (topography) with monochromatic synchrotron radiation

    NASA Technical Reports Server (NTRS)

    Steiner, Bruce; Kuriyama, Masao; Dobbyn, Ronald C.; Laor, Uri

    1988-01-01

    Structural information of special interest to crystal growers and device physicists is now available from high resolution monochromatic synchrotron diffraction imaging (topography). In the review, the importance of superior resolution in momentum transfer and in space is described, and illustrations are taken from a variety of crystals: gallium arsenide, cadmium telluride, mercuric iodide, bismuth silicon oxide, and lithium niobate. The identification and understanding of local variations in crystal growth processes are shown. Finally, new experimental opportunities now available for exploitation are indicated.

  2. New Forward and Diffractive Physics at CMS

    NASA Astrophysics Data System (ADS)

    Santoro, Alberto

    2011-04-01

    Forward and Diffractive Physics (FWP) in LHC is a new open window to understand this type of strong interactions. We will present a didactic description of the topics being developed at CMS. As we know there still is no new results to present for FWP. We are accumulating data to have soon new results. We will show a number of topics and the detectors properties to do the observation of several topologies. We expect to give an optimistic view of the area.

  3. DNA hydration studied by neutron fiber diffraction

    SciTech Connect

    Fuller, W.; Forsyth, V.T.; Mahendrasingam, A.; Langan, P.; Pigram, W.J.

    1994-12-31

    The development of neutron high angle fiber diffraction to investigate the location of water around the deoxyribonucleic acid (DNA) double-helix is described. The power of the technique is illustrated by its application to the D and A conformations of DNA using the single crystal diffractometer, D19, at the Institute Laue-Langevin, Grenoble and the time of flight diffractometer, SXD, at the Rutherford Appleton ISIS Spallation Neutron Source. These studies show the existence of bound water closely associated with the DNA. The patterns of hydration in these two DNA conformations are quite distinct and are compared to those observed in X-ray single crystal studies of two-stranded oligodeoxynucleotides. Information on the location of water around the DNA double-helix from the neutron fiber diffraction studies is combined with that on the location of alkali metal cations from complementary X-ray high angle fiber diffraction studies at the Daresbury Laboratory SRS using synchrotron radiation. These analyses emphasize the importance of viewing DNA, water and ions as a single system with specific interactions between the three components and provide a basis for understanding the effect of changes in the concentration of water and ions in inducing conformations] transitions in the DNA double-helix.

  4. Optical microscopy beyond the diffraction limit

    PubMed Central

    Smolyaninov, Igor I.

    2008-01-01

    Over the past century the resolution of far-field optical microscopes, which rely on propagating optical modes, was widely believed to be limited because of diffraction to a value on the order of a half-wavelength λ∕2 of the light used. Although immersion microscopes had slightly improved resolution on the order of λ∕2n, the increased resolution was limited by the small range of refractive indices, n, of available transparent materials. We are experiencing quick demolition of the diffraction limit in optical microscopy. Over the past few years numerous nonlinear optical microscopy techniques based on photoswitching and saturation of fluorescence demonstrated far-field resolution of 20 to 30 nm. The latest exciting example of these techniques has been demonstrated by Huang et al. [Science 319, 810–813 (2008)]. Moreover, recent progress in metamaterials indicates that artificial optical media can be created, which do not exhibit the diffraction limit. Resolution of linear “immersion” microscopes based on such metamaterials appears limited only by losses, which can be compensated by gain media. Thus, optical microscopy is quickly moving towards the 10 nm resolution scale, which should bring about numerous revolutionary advances in biomedical imaging. PMID:19404465

  5. Diffractive coherence in multilayer dielectric gratings

    SciTech Connect

    Shore, B.W.; Feit, M.D.; Perry, M.D.; Boyd, R.D.; Britten, J.A.; Li, Lifeng

    1995-05-26

    Successful operation of large-scale high-power lasers, such as those in use and planned at LLNL and elsewhere, require optical elements that can withstand extremely high fluences without suffering damage. Of particular concern are dielectric diffraction gratings used for beam sampling and pulse compression. Laser induced damage to bulk dielectric material originates with coupling of the electric field of the radiation to bound electrons, proceeding through a succession of mechanisms that couple the electron kinetic energy to lattice energy and ultimately to macroscopic structural changes (e.g. melting). The constructive interference that is responsible for the diffractive behavior of a grating or the reflective properties of a multilayer dielectric stack can enhance the electric field above values that would occur in unstructured homogeneous material. Much work has been done to model damage to bulk matter. The presence of nonuniform electric fields, resulting from diffractive coherence, has the potential to affect damage thresholds and requires more elaborate theory. We shall discuss aspects of work directed towards understanding the influence of dielectric structures upon damage, with particular emphasis on computations and interpretation of electric fields within dielectric gratings and multilayer dielectric stacks, noting particularly the interference effects that occur in these structures.

  6. Integrated Diffractive Optics for Surface Ion Traps

    NASA Astrophysics Data System (ADS)

    Streed, Erik; Ghadimi, Moji; Blums, Valdis; Norton, Benjamin; Connor, Paul; Amini, Jason; Volin, Curtis; Lobino, Mirko; Kielpinski, David

    2016-05-01

    Photonic interconnects are a bottleneck to achieving large-scale trapped ion quantum computing. We have modified a Georgia Tech Research Institute microwave chip trap by using e-beam lithography to write reflective diffractive collimating optics (80 μm x 127 μm, f=58.6 μm, λ=369.5nm) on the center electrode. The optics have an NA of 0.55 x 0.73, capturing 13.2% of the solid angle. To evaluate the optics 174Yb+ was loaded by isotope selective photo-ionization from a thermal oven and then shuttled to imaging sites. Near diffraction limited sub-wavelength ion images were obtained with an observed spot sized FWHM of 338 nm x 268 nm vs. a diffraction limit of 336 nm x 257 nm. The total photon collection efficiency was measured to be 5.2+/-1.2%. Coupling into a single mode fiber of up to 2.0+/-0.6% was observed, limited by mismatch in the coupling optics. Image mode quality indicates coupling up to 4% may be possible. Funding from Australian Research Council and IARPA.

  7. Enhanced high-speed coherent diffraction imaging

    NASA Astrophysics Data System (ADS)

    Potier, Jonathan; Fricker, Sebastien; Idir, Mourad

    2011-03-01

    Due to recent advances in X-ray microscopy, we are now able to image objects with nanometer resolution thanks to Synchrotron beam lines or Free Electron Lasers (FEL). The PCI (Phase Contrast Imaging) is a robust technique that can recover the wavefront from measurements of only few intensity pictures in the Fresnel diffraction region. With our fast straightforward calculus methods, we manage to provide the phase induced by a microscopic specimen in few seconds. We can therefore obtain high contrasted images from transparent materials at very small scales. To reach atomic resolution imaging and thus make a transition from the near to the far field, the Coherent Diffraction Imaging (CDI) technique finds its roots in the analysis of diffraction patterns to obtain the phase of the altered complex wave. Theoretical results about existence and uniqueness of this retrieved piece of information by both iterative and direct algorithms have already been released. However, performances of algorithms remain limited by the coherence of the X-ray beam, presence of random noise and the saturation threshold of the detector. We will present reconstructions of samples using an enhanced version of HIO algorithm improving the speed of convergence and its repeatability. As a first step toward a practical X-Ray CDI system, initial images for reconstructions are acquired with the laser-based CDI system working in the visible spectrum.

  8. Data Exploration Toolkit for serial diffraction experiments

    SciTech Connect

    Zeldin, Oliver B.; Brewster, Aaron S.; Hattne, Johan; Uervirojnangkoorn, Monarin; Lyubimov, Artem Y.; Zhou, Qiangjun; Zhao, Minglei; Weis, William I.; Sauter, Nicholas K.; Brunger, Axel T.

    2015-02-01

    This paper describes a set of tools allowing experimentalists insight into the variation present within large serial data sets. Ultrafast diffraction at X-ray free-electron lasers (XFELs) has the potential to yield new insights into important biological systems that produce radiation-sensitive crystals. An unavoidable feature of the ‘diffraction before destruction’ nature of these experiments is that images are obtained from many distinct crystals and/or different regions of the same crystal. Combined with other sources of XFEL shot-to-shot variation, this introduces significant heterogeneity into the diffraction data, complicating processing and interpretation. To enable researchers to get the most from their collected data, a toolkit is presented that provides insights into the quality of, and the variation present in, serial crystallography data sets. These tools operate on the unmerged, partial intensity integration results from many individual crystals, and can be used on two levels: firstly to guide the experimental strategy during data collection, and secondly to help users make informed choices during data processing.

  9. Pixelated diffraction signatures for explosive detection

    NASA Astrophysics Data System (ADS)

    O'Flynn, Daniel; Reid, Caroline; Christodoulou, Christiana; Wilson, Matt; Veale, Matthew C.; Seller, Paul; Speller, Robert

    2012-06-01

    Energy dispersive X-ray diffraction (EDXRD) is a technique which can be used to improve the detection and characterisation of explosive materials. This study has performed EDXRD measurements of various explosive compounds using a novel, X-ray sensitive, pixelated, energy resolving detector developed at the Rutherford Appleton Laboratory, UK (RAL). EDXRD measurements are normally performed at a fixed scattering angle, but the 80×80 pixel detector makes it possible to collect both spatially resolved and energy resolved data simultaneously. The detector material used is Cadmium Telluride (CdTe), which can be utilised at room temperature and gives excellent spectral resolution. The setup uses characteristics from both energy dispersive and angular dispersive scattering techniques to optimise specificity and speed. The purpose of the study is to develop X-ray pattern "footprints" of explosive materials based on spatial and energy resolved diffraction data, which can then be used for the identification of such materials hidden inside packages or baggage. The RAL detector is the first energy resolving pixelated detector capable of providing an energy resolution of 1.0-1.5% at energies up to 150 keV. The benefit of using this device in a baggage scanner would be the provision of highly specific signatures to a range of explosive materials. We have measured diffraction profiles of five explosives and other compounds used to make explosive materials. High resolution spectra have been obtained. Results are presented to show the specificity of the technique in finding explosives within baggage.

  10. Diffractive acoustic elements for laser ultrasonics

    NASA Astrophysics Data System (ADS)

    Clark, M.; Sharples, S. D.; Somekh, M. G.

    2000-05-01

    In a laser based surface acoustic wave (SAW) system the initial wavefront of the SAW is determined by the distribution of generating light on the sample surface. In our usual system the generating light is focussed into an arc or concentric arcs which spatially focus and temporally filter the SAWs. We have developed acoustic diffractive elements (DAEs) which, like diffractive optical elements, can shape the SAW distribution by diffraction. These DAEs are, like their optical analogues, highly dispersive and special consideration has to be made at the design stage in order to accommodate and utilize this dispersion. We demonstrate DAEs that produce well controlled multiple focii, frequency suppression and frequency selection. We also show that these complex acoustic elements can be accurately modelled using a simple angular spectrum technique. The DAEs are produced by computer generated holograms which control the generating distribution of light. These DAEs have applications in multi-frequency acoustic, harmonic acoustic imaging, SAW wavefront control and imaging on curved surfaces.

  11. The STAR Heavy Flavor Tracker

    NASA Astrophysics Data System (ADS)

    Videbaek, Flemming; STAR Collaboration

    2013-10-01

    The Heavy Flavor Tracker (HFT) is an on-going upgrade for the STAR detector at RHIC that aim to study heavy quark production. In relativistic heavy-ion collisions at RHIC, heavy quarks are primarily created from initial hard scatterings. Since their large masses are not easily affected by the strong interaction with QCD medium they may carry information from the system at early stage. The interaction between heavy quarks and the medium is sensitive to the medium dynamics; therefore heavy quarks are suggested as an ideal probe to quantify the properties of the strongly interacting QCD matter. The HFT detectors will study this via the topological reconstruction of open charm hadrons. The HFT that consists of a thin two layer inner Pixel vertex detector, and two outer concentric layers of silicon, the Silicon Strip Detector, and the Intermediate Silicon Tracker. We will show how this detector system can assess heavy flavor physics with great precision. An overview of the HFT that will be completed for the upcoming RHIC run-14, its expected performance, and current status will be presented. Supported by the Division of Nuclear Physics of the Office of Science of the U.S. Department of Energy.

  12. Multiplicity and transverse energy of produced gluon in relativistic heavy ion collision

    SciTech Connect

    Xiao Bowen

    2005-09-01

    We present a simple gluon production picture that is based on the McLerran-Venugopalan model and gluon BFKL evolution in relativistic heavy-ion collision. Results for the multiplicity and transverse energy distribution in both the central and forward rapidity regions for gluon production in early stages of heavy-ion collisions at the LHC are given. Finally, we provide a general qualitative discussion of the consequences of the forward rapidity behavior of produced gluons.

  13. Fission in intermediate energy heavy ion reactions

    SciTech Connect

    Wilhelmy, J.B.; Begemann-Blaich, M.; Blaich, T.; Boissevain, J.; Fowler, M.M.; Gavron, A.; Jacak, B.V.; Lysaght, P.S.; Britt, H.C.; Fields, D.J.

    1989-04-01

    A systematic study of reaction mechanisms at intermediate energies (50--100 MeV/A) has been performed at the Lawrence Berkeley Laboratory's BeValac using medium weight projectiles on medium and heavy element targets. A gas and plastic phoswich detector system was employed which gave large geometric coverage and a wide dynamic response. The particles identified with the gas detectors could be characterized into three components--intermediate mass fragments (IMF), fission fragments (FF) and heavy residues (HR). Major observed features are: the reaction yields are similar in the 50 to 100 MeV/A range, central collisions have high multiplicity of IMF's with broad angular correlations consistent with a large participant region, effects of final state Coulomb interactions are observed and give information on the size and temporal behavior of the source, true fission yields are dependent on target fissility and correlated with relatively peripheral collisions. Analysis of fission and evaporation yields implies limiting conditions for which fission decay remains a viable deexcitation channel. 15 refs., 7 figs.

  14. High Resolution Powder Diffraction and Structure Determination

    SciTech Connect

    Cox, D. E.

    1999-04-23

    It is clear that high-resolution synchrotrons X-ray powder diffraction is a very powerful and convenient tool for material characterization and structure determination. Most investigations to date have been carried out under ambient conditions and have focused on structure solution and refinement. The application of high-resolution techniques to increasingly complex structures will certainly represent an important part of future studies, and it has been seen how ab initio solution of structures with perhaps 100 atoms in the asymmetric unit is within the realms of possibility. However, the ease with which temperature-dependence measurements can be made combined with improvements in the technology of position-sensitive detectors will undoubtedly stimulate precise in situ structural studies of phase transitions and related phenomena. One challenge in this area will be to develop high-resolution techniques for ultra-high pressure investigations in diamond anvil cells. This will require highly focused beams and very precise collimation in front of the cell down to dimensions of 50 {micro}m or less. Anomalous scattering offers many interesting possibilities as well. As a means of enhancing scattering contrast it has applications not only to the determination of cation distribution in mixed systems such as the superconducting oxides discussed in Section 9.5.3, but also to the location of specific cations in partially occupied sites, such as the extra-framework positions in zeolites, for example. Another possible application is to provide phasing information for ab initio structure solution. Finally, the precise determination of f as a function of energy through an absorption edge can provide useful information about cation oxidation states, particularly in conjunction with XANES data. In contrast to many experiments at a synchrotron facility, powder diffraction is a relatively simple and user-friendly technique, and most of the procedures and software for data analysis

  15. Urban driving cycle results of retrofitted diesel oxidation catalysts on heavy duty vehicles

    SciTech Connect

    Brown, K.F.; Rideout, G.

    1996-09-01

    This paper presents the emissions testing results of various heavy duty engines and vehicles with and without retrofitted diesel oxidation catalyst technology. 1987 Cummins L10 and 1991 DDC 6V92TA DDECII engine results over the US Heavy Duty Transient Test are presented for comparison to chassis test results. The vehicles in this study include two urban buses, two school buses and three heavy duty trucks. The Central Business District, New York Bus and New York Composite urban driving cycles have been used to evaluate baseline emissions and the catalyst performance on a heavy duty chassis dynamometer. The results demonstrate that 25--45% particulate reduction is readily achievable on a wide variety of heavy duty vehicles. Significant carbon monoxide and hydrocarbon reductions were also observed.

  16. Heavy Quarkonium Production and Polarization

    NASA Astrophysics Data System (ADS)

    Kang, Zhong-Bo; Qiu, Jian-Wei; Sterman, George

    2012-03-01

    We present a perturbative QCD factorization formalism for the production of heavy quarkonia of large transverse momentum pT at collider energies, which includes both the leading-power (LP) and next-to-leading-power (NLP) contributions to the cross section in the mQ2/pT2 expansion for heavy quark mass mQ. We estimate fragmentation functions in the nonrelativistic QCD formalism and reproduce the bulk of the large enhancement found in explicit next-to-leading-order calculations in the color-singlet model. Heavy quarkonia produced from NLP channels prefer longitudinal polarization.

  17. Imaging using accelerated heavy ions

    SciTech Connect

    Chu, W.T.

    1982-05-01

    Several methods for imaging using accelerated heavy ion beams are being investigated at Lawrence Berkeley Laboratory. Using the HILAC (Heavy-Ion Linear Accelerator) as an injector, the Bevalac can accelerate fully stripped atomic nuclei from carbon (Z = 6) to krypton (Z = 34), and partly stripped ions up to uranium (Z = 92). Radiographic studies to date have been conducted with helium (from 184-inch cyclotron), carbon, oxygen, and neon beams. Useful ranges in tissue of 40 cm or more are available. To investigate the potential of heavy-ion projection radiography and computed tomography (CT), several methods and instrumentation have been studied.

  18. Generalized parton distributions and rapidity gap survival in exclusive diffractive pp scattering

    SciTech Connect

    Leonid Frankfurt; Charles Hyde-Wright; Mark Strikman; Christian Weiss

    2007-03-01

    We propose a new approach to the problem of rapidity gap survival (RGS) in the production of high-mass systems (H = dijet, heavy quarkonium, Higgs boson) in double-gap exclusive diffractive pp scattering, pp-->p + (gap) + H + (gap) + p. It is based on the idea that hard and soft interactions proceed over widely different time- and distance scales and are thus approximately independent. The high-mass system is produced in a hard scattering process with exchange of two gluons between the protons. Its amplitude is calculable in terms of the gluon generalized parton distributions (GPDs) in the protons, which can be measured in J= production in exclusive ep scattering. The hard scattering process is modified by soft spectator interactions, which we calculate in a model-independent way in terms of the pp elastic scattering amplitude. Contributions from inelastic intermediate states are suppressed. A simple geometric picture of the interplay of hard and soft interactions in diffraction is obtained. The onset of the black-disk limit in pp scattering at TeV energies strongly suppresses diffraction at small impact parameters and is the main factor in determining the RGS probability. Correlations between hard and soft interactions (e.g. due to scattering from the long-range pion field of the proton, or due to possible short-range transverse correlations between partons) further decrease the RGS probability. We also investigate the dependence of the diffractive cross section on the transverse momenta of the final-state protons (''diffraction pattern''). By measuring this dependence one can perform detailed tests of the interplay of hard and soft interactions, and even extract information about the gluon GPD in the proton. Such studies appear to be feasible with the planned forward detectors at the LHC.

  19. Biosorption of heavy metals

    SciTech Connect

    Volesky, B. |; Holan, Z.R.

    1995-05-01

    Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents. The assessment of the metal-building capacity of some new biosorbents is discussed. Lead and cadmium, for instance, have been effectively removed from very dilute solutions by the dried biomass of some ubiquitous species of brown marine algae such as Ascophyllum and Sargassum, which accumulate more than 30% of biomass dry weight in the metal. Mycelia of the industrial steroid-transforming fungi Rhizopus and Absidia are excellent biosorbents for lead, cadmium, copper, zinc, and uranium and also bind other heavy metals up to 25% of the biomass dry weight. Biosorption isotherm curves, derived from equilibrium batch sorption experiments, are used in the evaluation of metal uptake by different biosorbents. Further studies are focusing on the assessment of biosorbent performance in dynamic continuous-flow sorption systems. In the course of this work, new methodologies are being developed that are aimed at mathematical modeling of biosorption systems and their effective optimization. 115 refs., 7 figs., 3 tabs.

  20. Plants absorb heavy metals

    SciTech Connect

    Parry, J.

    1995-02-01

    Decontamination of heavy metals-polluted soils remains one of the most intractable problems of cleanup technology. Currently available techniques include extraction of the metals by physical and chemical means, such as acid leaching and electroosmosis, or immobilization by vitrification. There are presently no techniques for cleanup which are low cost and retain soil fertility after metals removal. But a solution to the problem could be on the horizon. A small but growing number of plants native to metalliferous soils are known to be capable of accumulating extremely high concentrations of metals in their aboveground portions. These hyperaccumulators, as they are called, contain up to 1,000 times larger metal concentrations in their aboveground parts than normal species. Their distribution is global, including many different families of flowering plants of varying growth forms, from herbaceous plants to trees. Hyperaccumulators absorb metals they do not need for their own nutrition. The metals are accumulated in the leaf and stem vacuoles, and to a lesser extent in the roots.

  1. Heavy-flavor-conserving hadronic weak decays of heavy baryons

    NASA Astrophysics Data System (ADS)

    Cheng, Hai-Yang; Cheung, Chi-Yee; Lin, Guey-Lin; Lin, Yeu-Chung; Yan, Tung-Mow; Yu, Hoi-Lai

    2016-03-01

    More than two decades ago, we studied heavy-flavor-conserving weak decays of heavy baryons within the framework that incorporates both heavy-quark and chiral symmetries. In view of the first observation of Ξ b - → Λ b 0 π - by LHCb recently, we have reexamined these decays and presented updated predictions. The predicted rates for Ξ b - → Λ b 0 π - in the MIT bag and diquark models are consistent with experiment. The major theoretical uncertainty stems from the evaluation of baryon matrix elements. The branching fraction of Ξ c → Λ c π is predicted to be of order 10-4. It is suppressed relative to {B}({Ξ}_bto {Λ}_bπ ) owing to the shorter lifetime of Ξ c relative to Ξ b and the destructive nonspectator W-exchange contribution. The kinematically accessible weak decays of the sextet heavy baryon Ω Q are Ω Q → Ξ Q π. Due to the absence of the {{B}}_6-{{B}}{_3-} transition in the heavy quark limit and the {{B}}_6-{{B}}_6 transition in the model calculations, Ω Q → Ξ Q π vanish in the heavy quark limit.

  2. Central sleep apnea

    MedlinePlus

    ... pressure (CPAP) , bilevel positive airway pressure (BiPAP) or adaptive servo-ventilation (ASV). Some types of central sleep ... et al. The treatment of central sleep apnea syndromes in adults: practice parameters with an evidence-based ...

  3. Central venous catheters - ports

    MedlinePlus

    Central venous catheter - subcutaneous; Port-a-Cath; InfusaPort; PasPort; Subclavian port; Medi - port; Central venous line - port ... catheter is attached to a device called a port that will be under your skin. The port ...

  4. Central Neuropathic Pain Syndromes.

    PubMed

    Watson, James C; Sandroni, Paola

    2016-03-01

    Chronic pain is common in patients with neurologic complications of a central nervous system insult such as stroke. The pain is most commonly musculoskeletal or related to obligatory overuse of neurologically unaffected limbs. However, neuropathic pain can result directly from the central nervous system injury. Impaired sensory discrimination can make it challenging to differentiate central neuropathic pain from other pain types or spasticity. Central neuropathic pain may also begin months to years after the injury, further obscuring recognition of its association with a past neurologic injury. This review focuses on unique clinical features that help distinguish central neuropathic pain. The most common clinical central pain syndromes-central poststroke pain, multiple sclerosis-related pain, and spinal cord injury-related pain-are reviewed in detail. Recent progress in understanding of the pathogenesis of central neuropathic pain is reviewed, and pharmacological, surgical, and neuromodulatory treatments of this notoriously difficult to treat pain syndrome are discussed. PMID:26944242

  5. Heavy Lift Launch Vehicle Concept

    NASA Technical Reports Server (NTRS)

    2004-01-01

    During the Space Shuttle development phase, Marshall plarners concluded a Heavy Lift Launch Vehicle (HLLV) would be needed for successful Space Industrialization. Shown here in this 1976's artist's conception is an early version of the HLLV during launch.

  6. Heavy Equipment Mechanic Program Standards.

    ERIC Educational Resources Information Center

    Georgia Univ., Athens. Dept. of Vocational Education.

    This publication contains statewide standards for the heavy equipment mechanic program in Georgia. The standards are divided into 12 categories: foundations (philosophy, purpose, goals, program objectives, availability, evaluation); admissions (admission requirements, provisional admission requirements, recruitment, evaluation and planning);…

  7. Heavy quark spectroscopy and decay

    SciTech Connect

    Schindler, R.H.

    1987-01-01

    The understanding of q anti q systems containing heavy, charmed, and bottom quarks has progressed rapidly in recent years, through steady improvements in experimental techniques for production and detection of their decays. These lectures are meant to be an experimentalist's review of the subject. In the first of two lectures, the existing data on the spectroscopy of the bound c anti c and b anti b systems will be discussed. Emphasis is placed on comparisons with the theoretical models. The second lecture covers the rapidly changing subject of the decays of heavy mesons (c anti q and b anti q), and their excited states. In combination, the spectroscopy and decays of heavy quarks are shown to provide interesting insights into both the strong and electroweak interactions of the heavy quarks. 103 refs., 39 figs.

  8. Electron diffraction of CBr4 in superfluid helium droplets: A step towards single molecule diffraction

    NASA Astrophysics Data System (ADS)

    He, Yunteng; Zhang, Jie; Kong, Wei

    2016-07-01

    We demonstrate the practicality of electron diffraction of single molecules inside superfluid helium droplets using CBr4 as a testing case. By reducing the background from pure undoped droplets via multiple doping, with small corrections for dimers and trimers, clearly resolved diffraction rings of CBr4 similar to those of gas phase molecules can be observed. The experimental data from CBr4 doped droplets are in agreement with both theoretical calculations and with experimental results of gaseous species. The abundance of monomers and clusters in the droplet beam also qualitatively agrees with the Poisson statistics. Possible extensions of this approach to macromolecular ions will also be discussed. This result marks the first step in building a molecular goniometer using superfluid helium droplet cooling and field induced orientation. The superior cooling effect of helium droplets is ideal for field induced orientation, but the diffraction background from helium is a concern. This work addresses this background issue and identifies a possible solution. Accumulation of diffraction images only becomes meaningful when all images are produced from molecules oriented in the same direction, and hence a molecular goniometer is a crucial technology for serial diffraction of single molecules.

  9. Electron diffraction of CBr4 in superfluid helium droplets: A step towards single molecule diffraction.

    PubMed

    He, Yunteng; Zhang, Jie; Kong, Wei

    2016-07-21

    We demonstrate the practicality of electron diffraction of single molecules inside superfluid helium droplets using CBr4 as a testing case. By reducing the background from pure undoped droplets via multiple doping, with small corrections for dimers and trimers, clearly resolved diffraction rings of CBr4 similar to those of gas phase molecules can be observed. The experimental data from CBr4 doped droplets are in agreement with both theoretical calculations and with experimental results of gaseous species. The abundance of monomers and clusters in the droplet beam also qualitatively agrees with the Poisson statistics. Possible extensions of this approach to macromolecular ions will also be discussed. This result marks the first step in building a molecular goniometer using superfluid helium droplet cooling and field induced orientation. The superior cooling effect of helium droplets is ideal for field induced orientation, but the diffraction background from helium is a concern. This work addresses this background issue and identifies a possible solution. Accumulation of diffraction images only becomes meaningful when all images are produced from molecules oriented in the same direction, and hence a molecular goniometer is a crucial technology for serial diffraction of single molecules. PMID:27448887

  10. Muscle diffraction theory. Relationship between diffraction subpeaks and discrete sarcomere length distributions.

    PubMed Central

    Judy, M M; Summerour, V; LeConey, T; Roa, R L; Templeton, G H

    1982-01-01

    A theoretical discussion is presented that describes the diffraction on monochromatic light by a three-dimensional sarcomere array having the following properties. The basic repetitive diffracting unit is the sarcomere. The contiguous arrangement of physically attached serial sarcomeres in the myofibril is contained within the model so that relative position of sarcomeres depend upon the lengths of intervening ones. Sarcomere length is described by a distribution function. This function may be discrete or continuous and contain one or more subpopulations. Two arrangements of sarcomeres are considered: (a) when sarcomeres of different lengths are arranged randomly in myofibrils the amplitude and width of mth order (m greater than or equal to 1) peaks and associated secondary diffraction maxima decrease and increase monotonically, respectively, as the standard deviation of the length distribution increases. No subpeaks are present regardless of the number of subpopulations within the distribution function. This behavior is shown to follow from the dependence of sarcomere position on the length of intervening sarcomeres. (b) When sarcomeres belonging to the same length subpopulation are arranged in serial contiguous fashion to form domains and more than one length subpopulation is present, then mth order diffraction peaks split to form subpeaks. The theoretical basis for this behavior is developed for the first time and may explain the subpeaks evident in diffraction patterns from cardiac and skeletal muscle. PMID:7059651

  11. Rigorous diffraction analysis using geometrical theory of diffraction for future mask technology

    NASA Astrophysics Data System (ADS)

    Chua, Gek S.; Tay, Cho J.; Quan, Chenggen; Lin, Qunying

    2004-05-01

    Advanced lithographic techniques such as phase shift masks (PSM) and optical proximity correction (OPC) result in a more complex mask design and technology. In contrast to the binary masks, which have only transparent and nontransparent regions, phase shift masks also take into consideration transparent features with a different optical thickness and a modified phase of the transmitted light. PSM are well-known to show prominent diffraction effects, which cannot be described by the assumption of an infinitely thin mask (Kirchhoff approach) that is used in many commercial photolithography simulators. A correct prediction of sidelobe printability, process windows and linearity of OPC masks require the application of rigorous diffraction theory. The problem of aerial image intensity imbalance through focus with alternating Phase Shift Masks (altPSMs) is performed and compared between a time-domain finite-difference (TDFD) algorithm (TEMPEST) and Geometrical theory of diffraction (GTD). Using GTD, with the solution to the canonical problems, we obtained a relationship between the edge on the mask and the disturbance in image space. The main interest is to develop useful formulations that can be readily applied to solve rigorous diffraction for future mask technology. Analysis of rigorous diffraction effects for altPSMs using GTD approach will be discussed.

  12. LCLS Heavy Met Outgassing Tests

    SciTech Connect

    Kishiyama, K. I.

    2010-12-01

    A Heavy Met that is 95% tungsten, 3% nickel and 2% iron and sintered to 100% density and is Ultra High Vacuum (UHV) compatible is proposed for use as the X-ray slit in the Front End Enclosure and the Fixed Mask for the Linac Coherent Light Source (LCLS). The Heavy Met was tested in the LLNL Vacuum Sciences and Engineering Lab (VSEL) to determine its outgassing rate and its overall compatibility with the vacuum requirements for LCLS.

  13. Open heavy-flavor measurements with ALICE at the LHC

    NASA Astrophysics Data System (ADS)

    Bailhache, R.

    2016-01-01

    ALICE is well equipped to reconstruct heavy-flavor particles down to low transverse momentum pT at mid and forward rapidity. An overview of the ALICE results obtained with the Run 1 data in pp (√5=2.76TeV and √s=7TeV), Pb-Pb (√Snn=2.76TeV) and p-Pb (√sNN=5.02 TeV) collisions is presented. In pp collisions the measured cross sections are well described by pQCD calculations. The charged-particle multiplicity dependence of heavy-flavor yields indicates that Multi-Parton Interactions contribute to the high-multiplicity pp collisions and affect charm and beauty production in a similar way. In p-Pb and Pb-Pb collisions the measured nuclear modification factors indicate a final-state energy loss of heavy- quarks in central Pb-Pb collisions. Furthermore, the observed positive heavy-flavor elliptic flow in semi-central Pb-Pb collisions gives a hint that charm quarks participate in the collective expansion of the medium at low pT. In high-multiplicity p-Pb collisions, a double-ridge structure is observed in the heavy-flavor decay electron-hadron azimuthal correlations at low pT similar to what is measured in the light-flavor sector. Such long-range correlations in ŋ could originate from a collective expansion of the system, as well as from gluon saturation in the initial state (color-glass condensate) or other mechanisms.

  14. Heavy Metal Stars

    NASA Astrophysics Data System (ADS)

    2001-08-01

    La Silla Telescope Detects Lots of Lead in Three Distant Binaries Summary Very high abundances of the heavy element Lead have been discovered in three distant stars in the Milky Way Galaxy . This finding strongly supports the long-held view that roughly half of the stable elements heavier than Iron are produced in common stars during a phase towards the end of their life when they burn their Helium - the other half results from supernova explosions. All the Lead contained in each of the three stars weighs about as much as our Moon. The observations show that these "Lead stars" - all members of binary stellar systems - have been more enriched with Lead than with any other chemical element heavier than Iron. This new result is in excellent agreement with predictions by current stellar models about the build-up of heavy elements in stellar interiors. The new observations are reported by a team of Belgian and French astronomers [1] who used the Coude Echelle Spectrometer on the ESO 3.6-m telescope at the La Silla Observatory (Chile). PR Photo 26a/01 : A photo of HD 196944 , one of the "Lead stars". PR Photo 26b/01 : A CES spectrum of HD 196944 . The build-up of heavy elements Astronomers and physicists denote the build-up of heavier elements from lighter ones as " nucleosynthesis ". Only the very lightest elements (Hydrogen, Helium and Lithium [2]) were created at the time of the Big Bang and therefore present in the early universe. All the other heavier elements we now see around us were produced at a later time by nucleosynthesis inside stars. In those "element factories", nuclei of the lighter elements are smashed together whereby they become the nuclei of heavier ones - this process is known as nuclear fusion . In our Sun and similar stars, Hydrogen is being fused into Helium. At some stage, Helium is fused into Carbon, then Oxygen, etc. The fusion process requires positively charged nuclei to move very close to each other before they can unite. But with increasing

  15. Scalar wave diffraction from a circular aperture

    SciTech Connect

    Cerjan, C.

    1995-01-25

    The scalar wave theory is used to evaluate the expected diffraction patterns from a circular aperture. The standard far-field Kirchhoff approximation is compared to the exact result expressed in terms of oblate spheroidal harmonics. Deviations from an expanding spherical wave are calculated for circular aperture radius and the incident beam wavelength using suggested values for a recently proposed point diffractin interferometer. The Kirchhoff approximation is increasingly reliable in the far-field limit as the aperture radius is increased, although significant errors in amplitude and phase persist.

  16. Flexible filamentous virus structure from fiber diffraction

    SciTech Connect

    Stubbs, Gerald; Kendall, Amy; McDonald, Michele; Bian, Wen; Bowles, Timothy; Baumgarten, Sarah; McCullough, Ian; Shi, Jian; Stewart, Phoebe; Bullitt, Esther; Gore, David; Ghabrial, Said

    2008-10-24

    Fiber diffraction data have been obtained from Narcissus mosaic virus, a potexvirus from the family Flexiviridae, and soybean mosaic virus (SMV), a potyvirus from the family Potyviridae. Analysis of the data in conjunction with cryo-electron microscopy data allowed us to determine the symmetry of the viruses and to make reconstructions of SMV at 19 {angstrom} resolution and of another potexvirus, papaya mosaic virus, at 18 {angstrom} resolution. These data include the first well-ordered data ever obtained for the potyviruses and the best-ordered data from the potexviruses, and offer the promise of eventual high resolution structure determinations.

  17. Elastic and diffractive scattering at D0

    SciTech Connect

    Edwards, Tamsin; /Manchester U.

    2004-04-01

    The first search for diffractively produced Z bosons in the muon decay channel is presented, using a data set collected by the D0 detector at the Fermilab Tevatron at {radical}s = 1.96 TeV between April and September 2003, corresponding to an integrated luminosity of approximately 110 pb{sup -1}. The first dN/d|t| distribution for proton-antiproton elastic scattering at this c.o.m. energy is also presented, using data collected by the D0 Forward Proton Detector between January and May 2002. The measured slope is reproduced by theoretical predictions.

  18. Diffractive Scattering and Gauge/String Duality

    ScienceCinema

    Tan, Chung-I [Brown University, Providence, Rhode Island, United States

    2009-09-01

    High-energy diffractive scattering will be discussed based on Gauge/String duality. As shown by Brower, Polchinski, Strassler and Tan, the ubiquitous Pomeron emerges naturally in gauge theories with string-theoretical descriptions. Its existence is intimately tied to gluons, and also to the energy-momentum tensor. With a confining dual background metric, the Pomeron can be interpreted as a 'massive graviton'. In a single unified step, both its infrared and ultraviolet properties are dealt with, reflecting confinement and conformal symmetry respectively. An effective field theory for high-energy scattering can be constructed. Applications based on this approach will also be described.

  19. Diffractive Optics From Self-Assembled DNA

    PubMed Central

    Levine, Zachary H.

    2002-01-01

    An algorithm is presented for assembling tiles into a variable spaced grating, the one-dimensional analog of a Fresnel zone plate. The algorithm supports multi-level gratings. The x-ray properties of such a grating, assumed to be constructed from DNA are estimated, leading to the conclusion that thick structures may be useful for intermediate energy x rays, but that thin structures for soft x rays are best used as disposable masks. The diffraction of cold, coherent atoms is a plausible application for single layer stencils.

  20. Near-perfect diffraction grating rhomb

    DOEpatents

    Wantuck, Paul J.

    1990-01-01

    A near-perfect grating rhomb enables an output beam to be diffracted to an angle offset from the input beam. The correcting grating is tipped relative to the dispersing grating to provide the offset angle. The correcting grating is further provided with a groove spacing which differs from the dispersing grating groove space by an amount effective to substantially remove angular dispersion in the output beam. A near-perfect grating rhomb has the capability for selective placement in a FEL to suppress sideband instabilities arising from the FEL.