Medium corrections within a multiple scattering theory
Energy Technology Data Exchange (ETDEWEB)
Chinn, C.R. [Oak Ridge National Lab., TN (United States)]|[Vanderbilt Univ., Nashville, TN (United States); Elster, Ch.; Thaler, R.M.
1993-04-01
A systematic formalism to include the effects of the nuclear medium into a multiple scattering expansion is developed. Although the use of a free nucleon-nucleon (NN) t-matrix accounts in an impulse approximation for the short-range interaction between the projectile and a target nucleon, the influence of the interactions between this target nucleon on the rest of the nucleus is often ignored. In the first order Watson expansion such higher order effects arise from the difference between the free NN propagator and the propagator in the nuclear medium. A formal framework consistent with a multiple scattering expansion has been constructed to include these contributions by using a nuclear mean field potential. The application of this formalism to nucleon scattering from various nuclei employing different local and nonlocal Hartree-Fock mean field potentials will be discussed.
Multiple scattering of polarized light in a turbid medium
Gorodnichev, E. E.; Kuzovlev, A. I.; Rogozkin, D. B.
2007-01-01
It is shown that multiple scattering of polarized light in a turbid medium can be represented as independent propagation of three basic modes: intensity and linearly and circularly polarized modes. Weak interaction between the basic modes can be described by perturbation theory and gives rise to "ov
Rakotonarivo, S T; Walker, S C; Kuperman, W A; Roux, P
2011-12-01
A method to actively localize a small perturbation in a multiple scattering medium using a collection of remote acoustic sensors is presented. The approach requires only minimal modeling and no knowledge of the scatterer distribution and properties of the scattering medium and the perturbation. The medium is ensonified before and after a perturbation is introduced. The coherent difference between the measured signals then reveals all field components that have interacted with the perturbation. A simple single scatter filter (that ignores the presence of the medium scatterers) is matched to the earliest change of the coherent difference to localize the perturbation. Using a multi-source/receiver laboratory setup in air, the technique has been successfully tested with experimental data at frequencies varying from 30 to 60 kHz (wavelength ranging from 0.5 to 1 cm) for cm-scale scatterers in a scattering medium with a size two to five times bigger than its transport mean free path.
Angle-resolved photon-coincidence measurements in a multiple-scattering medium
DEFF Research Database (Denmark)
Smolka, Stephan; Muskens, Otto L.; Lagendijk, Ad
2011-01-01
We present angle-resolved correlation measurements between photons after propagation through a three-dimensional disordered medium. The multiple-scattering process induces photon correlations that are directly measured for light sources with different photon statistics. We find that multiple...
Aubry, Alexandre
2009-01-01
We present an imaging technique particularly suited to the detection of a target embedded in a strongly scattering medium. Classical imaging techniques based on the Born approximation fail in this kind of configuration because of multiply scattered echoes and aberration distorsions. The experimental set up we consider uses an array of programmable transmitters/receivers. A target is placed behind a scattering medium. The impulse responses between all array elements are measured and form a matrix. The core of the method is to separate the single-scattered echo of the target from the multiple scattering background. This is possible because of a deterministic coherence along the antidiagonals of the array response matrix, which is typical of single scattering. Once this operation is performed, target detection is achieved by applying the DORT method (French acronym for decomposition of the time reversal operator). Experimental results are presented in the case of wide-band ultrasonic waves around 3 MHz. A 125-el...
Yu, Ting; Chaix, Jean-François; Komatitsch, Dimitri; Garnier, Vincent; Audibert, Lorenzo; Henault, Jean-Marie
2017-02-01
Multiple scattering is important when ultrasounds propagate in a heterogeneous medium such as concrete, the scatterer size of which is in the order of the wavelength. The aim of this work is to build a 2D numerical model of ultrasonic wave propagation integrating the multiple scattering phenomena in SPECFEM software. The coherent field of multiple scattering could be obtained by averaging numerical wave fields, and it is used to determine the effective phase velocity and attenuation corresponding to an equivalent homogeneous medium. After the creation of numerical model under several assumptions, its validation is completed in a case of scattering by one cylinder through the comparison with analytical solution. Two cases of multiple scattering by a set of cylinders at different concentrations are simulated to perform a parametric study (of frequency, scatterer concentration, scatterer size). The effective properties are compared with the predictions of Waterman-Truell model as well, to verify its validity.
Air bubbles in water: a strongly multiple scattering medium for acoustic waves.
Kafesaki, M; Penciu, R S; Economou, E N
2000-06-26
Using a newly developed multiple scattering scheme, we calculate band structure and transmission properties for acoustic waves propagating in bubbly water. We prove that the multiple scattering effects are responsible for the creation of wide gaps in the transmission even in the presence of strong positional and size disorder.
Le Bihan, Nicolas; Margerin, Ludovic
2009-07-01
In this paper, we present a nonparametric method to estimate the heterogeneity of a random medium from the angular distribution of intensity of waves transmitted through a slab of random material. Our approach is based on the modeling of forward multiple scattering using compound Poisson processes on compact Lie groups. The estimation technique is validated through numerical simulations based on radiative transfer theory.
Bihan, Nicolas Le
2009-01-01
In this paper, we present a nonparametric method to estimate the heterogeneity of a random medium from the angular distribution of intensity transmitted through a slab of random material. Our approach is based on the modeling of forward multiple scattering using Compound Poisson Processes on compact Lie groups. The estimation technique is validated through numerical simulations based on radiative transfer theory.
Berginc, G.
2013-11-01
We have developed a general formalism based on Green's functions to calculate the coherent electromagnetic field scattered by a random medium with rough boundaries. The approximate expression derived makes it possible to determine the effective permittivity, which is generalised for a layer of an inhomogeneous random medium with different types of particles and bounded with randomly rough interfaces. This effective permittivity describes the coherent propagation of an electromagnetic wave in a random medium with randomly rough boundaries. We have obtained an expression, which contains the Maxwell - Garnett formula at the low-frequency limit, and the Keller formula; the latter has been proved to be in good agreement with experiments for particles whose dimensions are larger than a wavelength.
Quantum Interference of Multiple Beams Induced by Multiple Scattering
DEFF Research Database (Denmark)
Ott, Johan Raunkjær; Mortensen, N. Asger; Lodahl, Peter
2011-01-01
We report on quantum interference induced by the transmission of quantized light through a multiple-scattering medium. We show that entangled states can be created by multiple-scattering and that quantum interference survives disorder averaging.......We report on quantum interference induced by the transmission of quantized light through a multiple-scattering medium. We show that entangled states can be created by multiple-scattering and that quantum interference survives disorder averaging....
Multiple scattering expansion with distortion
Tandy, P. C.; Thaler, R. M.
1980-12-01
A multiple scattering description of elastic scattering is formulated in terms of impulsive scatterings from single target nucleons and pairs of target nucleons. In this description, distortion effects on the projectile from the residual medium are also described by multiple scattering in terms of the same single and pair amplitudes. At the level of single scattering, this procedure yields the first order optical potential result of Kerman, McManus, and Thaler. When scattering from both single nucleons and pairs of nucleons is included, the method leads to a one-body integral equation which requires the physical projectile-nucleon and projectile-pair transition amplitudes as input. This input is similar, but not exactly equivalent to that required by the spectator expansion for the optical potential truncated at second order. A principal advantage of the present formulation is that there need be no explicit dependence upon the projection operator Q which projects off the target ground state. This feature introduces a scaling which appears to be a direct extension of the first order Kerman, McManus, and Thaler type of scaling. We follow up suggestions arising in the foregoing to show that the exact optical potential to second order in the spectator expansion can also be cast into a form having no explicit dependence upon Q, and requiring physical projectile-nucleon and projectile-pair transition amplitudes as input. NUCLEAR REACTIONS Multiple scattering from single nucleons, pairs of nucleons in nucleus. Distortion from residual medium. Optical potential. spectator expansion.
Superradiant Forward Scattering in Multiple Scattering
Chabe, Julien; Bienaime, Tom; Bachelard, Romain; Piovella, Nicola; Kaiser, Robin
2012-01-01
We report on an interference effect in multiple scattering by resonant scatterers resulting in enhanced forward scattering, violating Ohm's law for photons. The underlying mechanism of this wave effect is superradiance, which we have investigated using cold atoms as a toy model. We present numerical and experimental evidences for this superradiant forward scattering, which is robust against disorder and configuration averaging.
Coherent scattering of high-energy photon in a medium
Baier, V N
2001-01-01
The coherent scattering of photon in the Coulomb field (the Delbr\\"uck scattering) is considered for the momentum transfer $\\Delta \\ll m$ in the frame of the quasiclassical operator method. In high-energy region this process occurs over rather long distance. The process amplitude is calculated taking into account the multiple scattering of particles of the intermediate electron-positron pair in a medium. The result is the suppression of the process. Limiting cases of weak and strong effects of the multiple scattering are analyzed. The approach used is the generalization of the method developed by authors for consideration of the Landau-Pomeranchuk-Migdal effect.
A direct sampling method for inverse electromagnetic medium scattering
Ito, Kazufumi
2013-09-01
In this paper, we study the inverse electromagnetic medium scattering problem of estimating the support and shape of medium scatterers from scattered electric/magnetic near-field data. We shall develop a novel direct sampling method based on an analysis of electromagnetic scattering and the behavior of the fundamental solution. It is applicable to a few incident fields and needs only to compute inner products of the measured scattered field with the fundamental solutions located at sampling points. Hence, it is strictly direct, computationally very efficient and highly robust to the presence of data noise. Two- and three-dimensional numerical experiments indicate that it can provide reliable support estimates for multiple scatterers in the case of both exact and highly noisy data. © 2013 IOP Publishing Ltd.
Quantum optics in multiple scattering random media
DEFF Research Database (Denmark)
Lodahl, Peter
Quantum Optics in Multiple Scattering Random Media Peter Lodahl Research Center COM, Technical University of Denmark, Dk-2800 Lyngby, Denmark. Coherent transport of light in a disordered random medium has attracted enormous attention both from a fundamental and application point of view. Coherent...... quantum optics in multiple scattering media and novel fundamental phenomena have been predicted when examining quantum fluctuations instead of merely the intensity of the light [1]. Here I will present the first experimental study of the propagation of quantum noise through an elastic, multiple scattering...... medium [2]. Two different types of quantum noise measurements have been carried out: total transmission and short-range frequency correlations. When comparing shot noise (quantum) to technical noise (classical) we observed markedly different behavior, c.f. Fig. 1. The experimental results are found...
Medium energy hadron scattering from nuclei
Energy Technology Data Exchange (ETDEWEB)
Ginocchio, J.N.; Wenes, G.
1986-01-01
The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a ..gamma.. unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from /sup 154/Sm and /sup 154/Gd. 27 refs., 5 figs., 1 tab.
Scattering Induced Quantum Interference of Multiple Quantum Optical States
DEFF Research Database (Denmark)
Ott, Johan Raunkjær; Wubs, Martijn; Mortensen, N. Asger;
2011-01-01
Using a discrete mode theory for propagation of quantum optical states, we investigate the consequences of multiple scattering on the degree of quadrature entanglement and quantum interference. We report that entangled states can be created by multiple-scattering. We furthermore show that quantum...... interference induced by the transmission of quantized light through a multiple-scattering medium will persist even after averaging over an ensemble of scattering samples....
Multiple scattering effects on spaceborne lidar
Winker, David M.; Poole, Lamont R.
1992-01-01
A semianalytic Monte Carlo code originally developed for oceanographic calculations (Poole et al., 1981) has been modified for use in studying multiple scattering of space-based lidar. The approach is very similar to that described by Kunkel and Weinman (1976). The trajectory of each photon is followed from the transmitter through multiple scattering until the photon is either scattered backward out of the atmosphere, scattered forward into the ground and absorbed, or scattered out the sides of the cloud. The probability that the photon will return directly to the detector is computed and summed over all significant scattering events within the field of view of the detector. Multiple scattering of the lidar pulse causes an apparent increase in the transmittance of the medium. Multiple scattering effects for space-based lidar are more significant than for ground-based lidar due to the much larger beam diameter in the atmosphere. These larger diameters are due not only to the greater range between the lidar and the scattering volume, but also the need to maintain relatively large beam divergences to satisfy eye safety restrictions on the laser irradiance at the Earth's surface. The simulations presented here are for a wavelength of 1064 nm and the Deirmendjian C1 phase function, which yields an extinction coefficient of 17.259/km. We have looked at two cases: a space-based lidar at 296 km observing a C1 cloud 293 km from the lidar and, for comparison purposes, a ground-based lidar looking at a C1 cloud with a base height of either 2 km or 5 km. The C1 size distribution roughly approximates that of stratocumulus or altocumulus clouds (aufm Kampe and Weickmann, 1957).
Electromagnetic scattering by spheroidal volumes of discrete random medium
Mishchenko, Michael I.; Dlugach, Janna M.
2017-10-01
We use the superposition T-matrix method to compare the far-field scattering matrices generated by spheroidal and spherical volumes of discrete random medium having the same volume and populated by identical spherical particles. Our results fully confirm the robustness of the previously identified coherent and diffuse scattering regimes and associated optical phenomena exhibited by spherical particulate volumes and support their explanation in terms of the interference phenomenon coupled with the order-of-scattering expansion of the far-field Foldy equations. We also show that increasing nonsphericity of particulate volumes causes discernible (albeit less pronounced) optical effects in forward and backscattering directions and explain them in terms of the same interference/multiple-scattering phenomenon.
Spatial photon correlations in multiple scattering media
DEFF Research Database (Denmark)
Smolka, Stephan; Muskens, O.; Lagendijk, A.;
2010-01-01
We present the first angle-resolved measurements of spatial photon correlations that are induced by multiple scattering of light. The correlation relates multiple scattered photons at different spatial positions and depends on incident photon fluctuations.......We present the first angle-resolved measurements of spatial photon correlations that are induced by multiple scattering of light. The correlation relates multiple scattered photons at different spatial positions and depends on incident photon fluctuations....
Markov chain solution of photon multiple scattering through turbid slabs.
Lin, Ying; Northrop, William F; Li, Xuesong
2016-11-14
This work introduces a Markov Chain solution to model photon multiple scattering through turbid slabs via anisotropic scattering process, i.e., Mie scattering. Results show that the proposed Markov Chain model agree with commonly used Monte Carlo simulation for various mediums such as medium with non-uniform phase functions and absorbing medium. The proposed Markov Chain solution method successfully converts the complex multiple scattering problem with practical phase functions into a matrix form and solves transmitted/reflected photon angular distributions by matrix multiplications. Such characteristics would potentially allow practical inversions by matrix manipulation or stochastic algorithms where widely applied stochastic methods such as Monte Carlo simulations usually fail, and thus enable practical diagnostics reconstructions such as medical diagnosis, spray analysis, and atmosphere sciences.
Moliere multiple scattering theory revisited
Tarasov, Alexander
2012-01-01
We have received the rigorous relations between the screening parameters of the Moliere multiple scattering theory, instead of the approximate one obtained in the original paper by Moliere. We also calculated the relative Coulomb corrections to the first Born screening angle in the range from Z=4 to Z=82, and showed that their maximum values comprise the order of 40 percent. Additionally, we evaluated absolute and relative accuracies of the Moliere theory in determining the screening angle and have concluded that for Z~80 they are about 20, and 34 percents, respectively.
Multiple scattering Model in GEANT4
Urbàn, L
2002-01-01
We present a new multiple scattering (MSC) model to simulate the multiple scattering of charged particles in matter. This model does not use the Moliere formalism, it is based on the more complete Lewis theory. The model simulates the scattering of the particle after a given step, computes the path length correction and the lateral displacement as well.
Scattering of electromagnetic light waves from a deterministic anisotropic medium
Li, Jia; Chang, Liping; Wu, Pinghui
2015-11-01
Based on the weak scattering theory of electromagnetic waves, analytical expressions are derived for the spectral densities and degrees of polarization of an electromagnetic plane wave scattered from a deterministic anisotropic medium. It is shown that the normalized spectral densities of scattered field is highly dependent of changes of the scattering angle and degrees of polarization of incident plane waves. The degrees of polarization of scattered field are also subjective to variations of these parameters. In addition, the anisotropic effective radii of the dielectric susceptibility can lead essential influences on both spectral densities and degrees of polarization of scattered field. They are highly dependent of the effective radii of the medium. The obtained results may be applicable to determine anisotropic parameters of medium by quantitatively measuring statistics of a far-zone scattered field.
McCabe, David J; Austin, Dane R; Bondareff, Pierre; Walmsley, Ian A; Gigan, Sylvain; Chatel, Béatrice
2011-01-01
The multiple scattering of coherent light is a problem of both fundamental and applied importance. In optics, phase conjugation allows spatial focussing and imaging through a multiply scattering medium; however, temporal control is nonetheless elusive, and multiple scattering remains a challenge for femtosecond science. Here, we report on the spatially and temporally resolved measurement of a speckle field produced by the propagation of an ultrafast optical pulse through a thick strongly scattering medium. Using spectral pulse shaping, we demonstrate the spatially localized temporal recompression of the output speckle to the Fourier-limit duration, offering an optical analogue to time-reversal experiments in the acoustic regime. This approach shows that a multiply scattering medium can be put to profit for light manipulation at the femtosecond scale, and has a diverse range of potential applications that includes quantum control, biological imaging and photonics.
Analysis of multiple scattering effects in optical Doppler tomography
DEFF Research Database (Denmark)
Yura, H.T.; Thrane, L.; Andersen, Peter E.
2005-01-01
Optical Doppler tomography (ODT) combines Doppler velocimetry and optical coherence tomography (OCT) to obtain high-resolution cross-sectional imaging of particle flow velocity in scattering media such as the human retina and skin. Here, we present the results of a theoretical analysis of ODT where...... multiple scattering effects are included. The purpose of this analysis is to determine how multiple scattering affects the estimation of the depth-resolved localized flow velocity. Depth-resolved velocity estimates are obtained directly from the corresponding mean or standard deviation of the observed...... Doppler frequency spectrum. Thus, in the present analysis, the dependence of the mean and standard deviation of the Doppler shift on the scattering properties of the flowing medium are obtained. Taking the multiple scattering effects into account, we are able to explain previous measurements of depth...
Multiple scattering and energy loss in semi-inclusive deeply inelastic eA scattering
Guo, Xiaofeng
2007-01-01
We calculate the multiple scattering effect on single hadron production in semi-inclusive lepton-nucleus deeply inelastic scattering. We show that the quantum interference of multiple scattering amplitudes leads to suppression in hadron productions. At the leading power in medium length, the suppression can be approximately expressed in terms of a shift in $z$ of the fragmentation function $D(z)$, and could be therefore interpreted as the collisional energy loss. We compare our calculation with existing experimental data. We also discuss the effect of quark mass on the suppression. Our approach can be extended to other observables in hadronic collisions.
Electromagnetic Scattering in a Two-layered Medium
Institute of Scientific and Technical Information of China (English)
FENG LI-XIN; LI YUAN; Ma Fu-ming
2011-01-01
The object of this paper is to investigate the three-dimensional electro-magnetic scattering problems in a two-layered background medium.These problems have an important application in today's technology,such as to detect objects that are buried in soil.Here,we model both the exterior impedance problem and the inhomogeneous medium problem in R3.We establish uniqueness and existence for the solution of the two scattering problems,respectively.
An improved algorithm for cloud multiple scattering
Institute of Scientific and Technical Information of China (English)
Guibin Yuan; Xiaogang Sun; Jingmin Dai
2006-01-01
@@ Clouds' radiation characteristics are very important in clouds scene simulation, weather forecasting, pattern recognition, and other fields. Radiation of a cloud mainly comes from its multiple scattering. A new algorithm to calculate multiple scattering, called build-up factor algorithm, is proposed in this paper. In this algorithm, a modified gamma distribution is assumed to describe droplets distribution inside a cloud, then the radiation transport equation is calculated to get the solution of single scattering, and finally, a build-up factor is defined to estimate the multiple scattering contributions. This algorithm considers both single scattered radiance and multiple scattered radiance and needs shorter computing time. It can be used in real time simulations.
Multiple scattering of ultrasound in weakly inhomogeneous media: application to human soft tissues
Aubry, Alexandre
2010-01-01
Waves scattered by a weakly inhomogeneous random medium contain a predominant single scattering contribution as well as a multiple scattering contribution which is usually neglected, especially for imaging purposes. We propose a method, based on random matrix theory, in order to separate the single and multiple scattering contributions. The experimental set up uses an array of programmable sources/receivers placed in front of the medium. The impulse responses between every couple of transducers are measured and form a matrix. Single-scattering contributions are shown to exhibit a deterministic coherence along the antidiagonals of the array response matrix, whatever the distribution of inhomogeneities. This property is taken advantage of to discriminate single from multiple-scattered waves. This allows one to evaluate the absorption losses and the scattering losses separately, by comparing the multiple scattering intensity with a radiative transfer model. Moreover, the relative contribution of multiple scatter...
Quantum Interference and Entanglement Induced by Multiple Scattering of Light
DEFF Research Database (Denmark)
Ott, Johan Raunkjær; Mortensen, Asger; Lodahl, Peter
2010-01-01
We report on the effects of quantum interference induced by the transmission of an arbitrary number of optical quantum states through a multiple-scattering medium. We identify the role of quantum interference on the photon correlations and the degree of continuous variable entanglement between tw...
Quantum correlations induced by multiple scattering of quadrature squeezed light
DEFF Research Database (Denmark)
Lodahl, Peter
2006-01-01
Propagating quadrature squeezed light through a multiple scattering random medium is found to induce pronounced spatial quantum correlations that have no classical analogue. The correlations are revealed in the number of photons transported through the sample that can be measured from the intensity...
Atomic decay near a quantized medium of absorbing scatterers
Suttorp, L.G.; van Wonderen, A.J.
2010-01-01
The decay of an excited atom in the presence of a medium that both scatters and absorbs radiation is studied with the help of a quantum-electrodynamical model. The medium is represented by a half-space filled with a randomly distributed set of non-overlapping spheres, which consist of a linear absor
Nucleon-nucleon scattering at medium energies
Afnan, I. R.
1984-03-01
A model of the N-N potential, at medium energies, in the frame work of the BB-πBB equations, is presented. The derivation is based on the Cloudy Bag Model Hamiltonian. Recent N-N calculations are reviewed in the frame work of the model. Theoretical methods for the analysis of dibaryon resonances are compared.
Nucleon-nucleon scattering at medium energies
Energy Technology Data Exchange (ETDEWEB)
Afnan, I.R. (Flinders Univ. of South Australia, Bedford Park. School of Physical Sciences)
1984-03-26
A model of the N-N potential, at medium energies, in the framework of the BB-..pi..BB equations, is presented. The derivation is based on the Cloudy Bag Model Hamiltonian. Recent N-N calculations are reviewed in the framework of the model. Theoretical methods for the analysis of dibaryon resonances are compared. 30 refs.
Focusing coherent light through a nonlinear scattering medium
Frostig, Hadas; Derevyanko, Stanislav; Silberberg, Yaron
2016-01-01
Wavefront shaping is a powerful technique that can be used to focus light through scattering media, with the limitation that the obtained focus contains a small fraction of the total power. The method is based on the assumption that the field at the output is a linear superposition of the modes traveling through different paths in the medium. However, when the scattering medium also exhibits nonlinearity, as may occur in multiphoton microscopy, this assumption is violated and the applicability of wavefront shaping becomes unclear. Here we show that using adaptive optimization of the wavefront light can still be controlled and focused through a nonlinear scattering medium, and that the focused fraction of power can be significantly enhanced in the presence of moderate positive nonlinearity. Our results suggest that the use of short pulses for focusing through scattering media with a mild self-focusing response might be favorable to the use of continuous-wave light.
Collective hypersonic excitations in strongly multiple scattering colloids.
Still, T; Gantzounis, G; Kiefer, D; Hellmann, G; Sainidou, R; Fytas, G; Stefanou, N
2011-04-29
Unprecedented low-dispersion high-frequency acoustic excitations are observed in dense suspensions of elastically hard colloids. The experimental phononic band structure for SiO(2) particles with different sizes and volume fractions is well represented by rigorous full-elastodynamic multiple-scattering calculations. The slow phonons, which do not relate to particle resonances, are localized in the surrounding liquid medium and stem from coherent multiple scattering that becomes strong in the close-packing regime. Such rich phonon-matter interactions in nanostructures, being still unexplored, can open new opportunities in phononics.
Resonance scattering of canonical elastic shells in absorbing fluid medium
Institute of Scientific and Technical Information of China (English)
ZHUO Linkai; FAN Jun; TANG Weilin
2008-01-01
Resonance scattering of elastic spherical shell and cylindrical shell while the sur-rounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable resul twould be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surround-ing fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little in fluence on the low-frequency resonance scattering induced by the filler inside the shell.
Multiple light scattering in porous gallium phosphide
Bret, Boris Paul Jean
2005-01-01
This thesis presents an experimental study on multiple light scattering, with the necessary introductions: theoretical background and sample preparation. The emphasis is put on the effects of the multiple scattering of waves, i.e., where interference effects exist and are significant, in the search for Anderson localization. In ensemble-averaged random media, there exists a cone of light, superimposed on the diffuse background, in the exact backscattering direction, due to the constructive in...
Spectator expansion in multiple scattering theory
Energy Technology Data Exchange (ETDEWEB)
Siciliano, E.R.; Thaler, R.M.
1977-10-01
A finite expansion for the scattering of a structureless projectile from a complex target of A particles is presented. This development is given as a spectator expansion, in the sense that the first term represents the scattering of the projectile from single target constitutent particles, with all other target particles playing a passive role (i.e., acting as spectators). Similarly, the second term represents the scattering from pairs of target particles with (A-2) spectators, and so on. It is demonstrated that such expansions, one of which has been obtained previously as a resummation of the multiple scattering series, are very general in nature and obtain under circumstances for which the standard multiple scattering treatment is not valid.
A direct sampling method to an inverse medium scattering problem
Ito, Kazufumi
2012-01-10
In this work we present a novel sampling method for time harmonic inverse medium scattering problems. It provides a simple tool to directly estimate the shape of the unknown scatterers (inhomogeneous media), and it is applicable even when the measured data are only available for one or two incident directions. A mathematical derivation is provided for its validation. Two- and three-dimensional numerical simulations are presented, which show that the method is accurate even with a few sets of scattered field data, computationally efficient, and very robust with respect to noises in the data. © 2012 IOP Publishing Ltd.
A two-stage method for inverse medium scattering
Ito, Kazufumi
2013-03-01
We present a novel numerical method to the time-harmonic inverse medium scattering problem of recovering the refractive index from noisy near-field scattered data. The approach consists of two stages, one pruning step of detecting the scatterer support, and one resolution enhancing step with nonsmooth mixed regularization. The first step is strictly direct and of sampling type, and it faithfully detects the scatterer support. The second step is an innovative application of nonsmooth mixed regularization, and it accurately resolves the scatterer size as well as intensities. The nonsmooth model can be efficiently solved by a semi-smooth Newton-type method. Numerical results for two- and three-dimensional examples indicate that the new approach is accurate, computationally efficient, and robust with respect to data noise. © 2012 Elsevier Inc.
Linearized inversion of multiple scattering seismic energy
Aldawood, Ali; Hoteit, Ibrahim; Zuberi, Mohammad
2014-05-01
Internal multiples deteriorate the quality of the migrated image obtained conventionally by imaging single scattering energy. So, imaging seismic data with the single-scattering assumption does not locate multiple bounces events in their actual subsurface positions. However, imaging internal multiples properly has the potential to enhance the migrated image because they illuminate zones in the subsurface that are poorly illuminated by single scattering energy such as nearly vertical faults. Standard migration of these multiples provides subsurface reflectivity distributions with low spatial resolution and migration artifacts due to the limited recording aperture, coarse sources and receivers sampling, and the band-limited nature of the source wavelet. The resultant image obtained by the adjoint operator is a smoothed depiction of the true subsurface reflectivity model and is heavily masked by migration artifacts and the source wavelet fingerprint that needs to be properly deconvolved. Hence, we proposed a linearized least-square inversion scheme to mitigate the effect of the migration artifacts, enhance the spatial resolution, and provide more accurate amplitude information when imaging internal multiples. The proposed algorithm uses the least-square image based on single-scattering assumption as a constraint to invert for the part of the image that is illuminated by internal scattering energy. Then, we posed the problem of imaging double-scattering energy as a least-square minimization problem that requires solving the normal equation of the following form: GTGv = GTd, (1) where G is a linearized forward modeling operator that predicts double-scattered seismic data. Also, GT is a linearized adjoint operator that image double-scattered seismic data. Gradient-based optimization algorithms solve this linear system. Hence, we used a quasi-Newton optimization technique to find the least-square minimizer. In this approach, an estimate of the Hessian matrix that contains
Multiple Scattering, Underlying Event, and Minimum Bias
Gustafson, Gosta
2007-01-01
In this talk I first discuss the experimental evidence for multiple scattering and the properties of the underlying event. The extensive analyses by Rick Field of data from CDF cannot be reconciled with traditional wisdom concerning multiple collisions and the AGK cutting rules. Data seem to imply some kind of color recombination or unexpectedly strong effects from pomeron vertices. I then discuss theoretical ideas concerning the relation between multiple collisions and unitarity: the AGK rules, IP loops, dipole cascade models and diffraction.
Choi, Youngwoon; Hillman, Timothy R.; Choi, Wonjun; Lue, Niyom; Dasari, Ramachandra R.; So, Peter T. C.; Choi, Wonshik; Yaqoob, Zahid
2014-01-01
Multiple scatterings occurring in a turbid medium attenuate the intensity of propagating waves. Here, we propose a method to efficiently deliver light energy to the desired target depth in a scattering medium. We measure the time-resolved reflection matrix of a scattering medium using coherent time-gated detection. From this matrix, we derive and experimentally implement an incident wave pattern that optimizes the detected signal corresponding to a specific arrival time. This leads to enhanced light delivery at the target depth. The proposed method will lay a foundation for efficient phototherapy and deep-tissue in vivo imaging in the near future. PMID:24483661
Medium-modified average multiplicity and multiplicity fluctuations in jets
Energy Technology Data Exchange (ETDEWEB)
Perez-Ramos, Redamy [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
2009-05-15
The energy evolution of average multiplicities and multiplicity fluctuations in jets produced in heavy-ion collisions is investigated from a toy QCD-inspired model. In this model, we use modified splitting functions accounting for medium-enhanced radiation of gluons by a fast parton which propagates through the quark gluon plasma. The leading contribution of the standard production of soft hadrons is enhanced by a factor {radical}(N{sub s}) while next-to-leading order (NLO) corrections are suppressed by 1/{radical}(N{sub s}), where the parameter N{sub s}>1 accounts for the induced-soft gluons in the medium. Our results for such global observables are cross-checked and compared with their limits in the vacuum. (orig.)
Multiple Scatters in Single Site Gamma Backgrounds
Energy Technology Data Exchange (ETDEWEB)
Brodsky, J. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2016-09-16
nEXO aims to reduce its gamma backgrounds by taking advantage of the fact that a large number of gammas that would otherwise be backgrounds will undergo multiple compton scattering in the TPC and produce spatially distinct signals. These multi-sited (MS) events can be excluded from the 0νββ search.
Multiple Scattering of Quantum Optical States
DEFF Research Database (Denmark)
Ott, Johan Raunkjær; Mortensen, N. Asger; Lodahl, Peter
2011-01-01
fluctuations [3]. Only recently focus has reached the combination of quantum optics and multiple scattering, see e.g. references [4–7] and references therein. The experimental realization of strongly enhanced light-matter interaction in disordered photonic crystal waveguides, enabling cavity quantum...
Wave scattering in a multiscale random inhomogeneous medium
Tinin, Mikhail V.
2004-04-01
In this paper, using the Fock method of the fifth parameter and weighted Fourier-transform with respect to the coordinates of the source and observer, an integral representation is obtained for the wave field in a randomly inhomogeneous medium without invoking the assumption about small-angle propagation. Random trajectory variations to a first approximation are taken into account in calculating the partial wave phase (the expression under the integral sign). The expressions for the field in a medium with different-scale irregularities and for the scintillation index, obtained using this integral representation, are compared with known results. The good agreement with results from the theory of single scattering in a medium with background irregularities, and with investigations of the scintillation index made in terms of Rytov's method and path integrals, indicates that it is possible to use the approach developed in this study to describe the effects of simultaneous influence of different-scale irregularities.
Observation of spatial quantum correlations induced by multiple scattering of nonclassical light.
Smolka, S; Huck, A; Andersen, U L; Lagendijk, A; Lodahl, P
2009-05-15
We present the experimental realization of spatial quantum correlations of photons that are induced by multiple scattering of squeezed light. The quantum correlation relates photons propagating along two different light paths through the random medium and is infinite in range. Both positive and negative spatial quantum correlations are observed when varying the quantum state incident to the multiple scattering medium, and the strength of the correlations is controlled by the number of photons. The experimental results are in excellent agreement with recent theoretical proposals by implementing the full quantum model of multiple scattering.
Multiple-scattering corrections to the Beer-Lambert law
Energy Technology Data Exchange (ETDEWEB)
Zardecki, A.
1983-01-01
The effect of multiple scattering on the validity of the Beer-Lambert law is discussed for a wide range of particle-size parameters and optical depths. To predict the amount of received radiant power, appropriate correction terms are introduced. For particles larger than or comparable to the wavelength of radiation, the small-angle approximation is adequate; whereas for small densely packed particles, the diffusion theory is advantageously employed. These two approaches are used in the context of the problem of laser-beam propagation in a dense aerosol medium. In addition, preliminary results obtained by using a two-dimensional finite-element discrete-ordinates transport code are described. Multiple-scattering effects for laser propagation in fog, cloud, rain, and aerosol cloud are modeled.
Baryshevsky, V G
2013-01-01
This paper considers the refraction and diffraction of waves in three-dimensional crystals formed by anisotropically scattering centers. The partial wave expansion method is used to consider the effect of multiple rescattering of waves by centers composing a crystal. The expression for the refractive index of a crystal is derived. It is shown that instead of the diagonal elements of the scattering matrix $\\mathbf{T}$, appearing in the expression for the refractive index of a chaotic medium, the derived expression includes the diagonal elements of the reaction matrix $\\mathbf{K}$. This fact is taken into account in writing the equations describing the dynamical diffraction of waves in a crystal. The results can be of interest for research into, e.g., diffraction of cold neutrons and photons in crystals, nanocrystalline materials, as well as for the description of parametric and diffraction radiation in electromagnetic crystals formed by anisotropically scattering centers.
Theory of Multiple Coulomb Scattering from Extended Nuclei
Cooper, L. N.; Rainwater, J.
1954-08-01
Two independent methods are described for calculating the multiple scattering distribution for projected angle scattering resulting when very high energy charged particles traverse a thick scatterer. The results are compared with the theories of Moliere and Olbert.
A Multiple Scattering Theory for Proton Penetration
Institute of Scientific and Technical Information of China (English)
YANG Dai-Lun; WU Zhang-Wen; JIANG Steve-Bin; LUO Zheng-Ming
2004-01-01
@@ We extend the electron small-angle multiple scattering theory to proton penetration. After introducing the concept of narrow energy spectra, the proton energy loss process is included in the proton deep penetration theory. It precisely describes the whole process of proton penetration. Compared to the Monte Carlo method,this method maintains the comparable precision and possesses much higher computational efficiency. Thus, it shows the real feasibility of applying this algorithm to proton clinical radiation therapy.
Positronium-alkali atom scattering at medium energies
Energy Technology Data Exchange (ETDEWEB)
Chakraborty, Ajoy [Laban Hrad Vidyapith, AD-369, Salt Lake City, Kolkata 700 064 (India); Basu, Arindam [Department of Physics, Maheshtala College, Chandannagar, South 24 Parganas, Kolkata 700 140 (India); Sarkar, Nirmal K [Sodepur Chandrachur Vidyapith, 1, Desh Bandhu Nagar, Sodepur, 743 174 (India); Sinha, Prabal K [Department of Physics, Bangabasi College, 19, Raj Kumar Chakravorty Sarani, Kolkata 700 009 (India)
2004-04-28
We investigate the scattering of orthopositronium (o-Ps) atom off different atomic alkali targets (Na to Cs) at low and medium energies (up to 120 eV). Projectile-elastic and target-elastic close-coupling models have been employed to investigate the systems in addition to the static-exchange model. Elastic, excitation and total cross sections have been reported for all four systems. The magnitude of the alkali excitation cross section increases with increasing atomic number of the target atom while the position of the peak value shifts towards lower incident energies. The magnitudes of the Ps excitation and ionization cross sections increase steadily with atomic number with no change in the peak position. The reported results show regular behaviour with increasing atomic number of the target atom. Scattering parameters for the Ps-Rb and Ps-Cs systems are being reported for the first time.
Terahertz scattering by granular composite materials: An effective medium theory
Kaushik, Mayank; Ng, Brian W.-H.; Fischer, Bernd M.; Abbott, Derek
2012-01-01
Terahertz (THz) spectroscopy and imaging have emerged as important tools for identification and classification of various substances, which exhibit absorption characteristics at distinct frequencies in the THz range. The spectral fingerprints can potentially be distorted or obscured by electromagnetic scattering caused by the granular nature of some substances. In this paper, we present THz time domain transmission measurements of granular polyethylene powders in order to investigate an effective medium theory that yields a parameterized model, which can be used to estimate the empirical measurements to good accuracy.
Experimental demonstration of spatial quantum correlations in multiple scattering media
DEFF Research Database (Denmark)
Smolka, Stephan; Huck, Alexander; Andersen, Ulrik Lund;
2009-01-01
We demonstrate that spatial quantum correlations are induced by multiple scattering of squeezed light. The correlation relates multiple scattered photons at different spatial positions, and is tunable by varying photon fluctuations of the illuminating beam.......We demonstrate that spatial quantum correlations are induced by multiple scattering of squeezed light. The correlation relates multiple scattered photons at different spatial positions, and is tunable by varying photon fluctuations of the illuminating beam....
Coulomb interaction in multiple scattering theory
Ray, L.; Hoffmann, G. W.; Thaler, R. M.
1980-10-01
The treatment of the Coulomb interaction in the multiple scattering theories of Kerman-McManus-Thaler and Watson is examined in detail. By neglecting virtual Coulomb excitations, the lowest order Coulomb term in the Watson optical potential is shown to be a convolution of the point Coulomb interaction with the distributed nuclear charge, while the equivalent Kerman-McManus-Thaler Coulomb potential is obtained from an averaged, single-particle Coulombic T matrix. The Kerman-McManus-Thaler Coulomb potential is expressed as the Watson Coulomb term plus additional Coulomb-nuclear and Coulomb-Coulomb cross terms, and the omission of the extra terms in usual Kerman-McManus-Thaler applications leads to negative infinite total reaction cross section predictions and incorrect pure Coulomb scattering limits. Approximations are presented which eliminate these anomalies. Using the two-potential formula, the full projectile-nucleus T matrix is separated into two terms, one resulting from the distributed nuclear charge and the other being a Coulomb distorted nuclear T matrix. It is shown that the error resulting from the omission of the Kerman-McManus-Thaler Coulomb terms is effectively removed when the pure Coulomb T matrix in Kerman-McManus-Thaler is replaced by the analogous quantity in the Watson approach. Using the various approximations, theoretical angular distributions are obtained for 800 MeV p+208Pb elastic scattering and compared with experimental data. NUCLEAR REACTIONS 208Pb(p, p), E=0.8 GeV, Kerman, McManus, and Thaler, and Watson multiple scattering theories, Coulomb correction terms, high momentum transfer.
Low frequency sound scattering from spherical assemblages of bubbles using effective medium theory.
Hahn, Thomas R
2007-12-01
The determination of the acoustic field scattered by an underwater assembly of gas bubbles or similar resonant monopole scatterers is of considerable theoretical and practical interest. This problem is addressed from a theoretical point of view within the framework of the effective medium theory for the case of spherically shaped assemblages. Although being valid more generally, the effective medium theory is an ideal instrument to study multiple scattering effects such as low frequency collective resonances, acoustically coupled breathing modes of the entire assembly. Explicit expressions for the scattering amplitude and cross sections are derived, as well as closed form expressions for the resonance frequency and spectral shape of the fundamental collective mode utilizing analytical S-matrix methods. This approach allows, in principle, a simultaneous inversion for the assembly radius and void fraction directly from the scattering cross sections. To demonstrate the validity of the approach, the theory is applied to the example of idealized, spherically shaped schools of swim bladder bearing fish. The analytic results of the theory are compared to numerical first-principle benchmark computations and excellent agreement is found, even for densely packed schools and frequencies across the bladder resonance.
Propagation of coherent polarized light in turbid highly scattering medium.
Doronin, Alexander; Macdonald, Callum; Meglinski, Igor
2014-02-01
Within the framework of further development of unified Monte Carlo code for the needs of biomedical optics and biophotonics, we present an approach for modeling of coherent polarized light propagation in highly scattering turbid media, such as biological tissues. The temporal coherence of light, linear and circular polarization, interference, and the helicity flip of circularly polarized light due to reflection at the medium boundary and/or backscattering events are taken into account. To achieve higher accuracy in the results and to speed up the modeling, the implementation of the code utilizes parallel computing on NVIDIA graphics processing units using Compute Unified Device Architecture. The results of the simulation of coherent linearly and circularly polarized light are presented in comparison with the results of known theoretical studies and the results of alternative modelings.
Scattering optical elements: stand-alone optical elements exploiting multiple light scattering
Park, Jongchan; Park, Chunghyun; Lee, KyeoReh; Lee, Heon; Cho, Yong-Hoon; Park, YongKeun
2016-01-01
Optical design and fabrication techniques are crucial for making optical elements. From conventional lenses to diffractive optical elements, and to recent metasurfaces, various types of optical elements have been proposed to manipulate light where optical materials are fabricated into desired structures. Here, we propose a scattering optical element (SOE) which exploits multiple light scattering and wavefront shaping. Instead of fabricating optical materials, the SOE consists of a disordered medium and a photopolymer-based wavefront recorder, with shapes the wavefront of impinging light on demand. With the proposed stand-alone SOEs, we experimentally demonstrate control of various properties of light, including intensity, polarisation, spectral frequency and near field. Due to the tremendous freedom brought about by disordered media, the proposed approach will provide unexplored routes to manipulate arbitrary optical fields in stand-alone optical elements.
Investigation of multiple scattering effects in aerosols
Deepak, A.
1980-01-01
The results are presented of investigations on the various aspects of multiple scattering effects on visible and infrared laser beams transversing dense fog oil aerosols contained in a chamber (4' x 4' x 9'). The report briefly describes: (1) the experimental details and measurements; (2) analytical representation of the aerosol size distribution data by two analytical models (the regularized power law distribution and the inverse modified gamma distribution); (3) retrieval of aerosol size distributions from multispectral optical depth measurements by two methods (the two and three parameter fast table search methods and the nonlinear least squares method); (4) modeling of the effects of aerosol microphysical (coagulation and evaporation) and dynamical processes (gravitational settling) on the temporal behavior of aerosol size distribution, and hence on the extinction of four laser beams with wavelengths 0.44, 0.6328, 1.15, and 3.39 micrometers; and (5) the exact and approximate formulations for four methods for computing the effects of multiple scattering on the transmittance of laser beams in dense aerosols, all of which are based on the solution of the radiative transfer equation under the small angle approximation.
NEXAFS multiple scattering calculations of KO2
Institute of Scientific and Technical Information of China (English)
M.Pedio; Z.Y.Wu; M.Benfatto; A.Mascaraque; E.Michel; C.Crotti; M.Pel
2001-01-01
Since many years the oxidation of alkali metals has being attracted much interest due to the catalytic properties of metal promoters and the simple electronic structure of alkali atoms.The alkali-oxides phase diagram indicates that the interaction of oxygen with alkali metals can lead to the formation of different atomic O2 ions and molecular O2 and O22- ions.Potassium superoxide has been prepared in situ and high resolution O e-edge absorption NEXAFS spectra have been measured at the VUV beam-Line at ELETTRA facility.The experimental data have been analyzed by multiple scattering approach deriving many geometrical and electronic is of the KO2 type with an O-O distance of about 1.35A and that the transition involving singleπ molecular empty state of the superoxied O2 anion has a fine structure.Multiple Scattering self consistent calculation indicates that the bond between oxygen anion adn K atom is totally ionic and that the fine structure is essentially due to solid state effects.
Joshi, Aditya; Lindsey, Brooks; Dayton, Paul; Pinton, Gianmarco; Muller, Marie
2017-03-07
- Ultrasound contrast agents (UCA), such as microbubbles, enhance the scattering properties of blood, which is otherwise hypoechoic. The multiple scattering interactions of the acoustic field with UCA's are poorly understood due to the complexity of the multiple scattering theories and the nonlinear microbubble response. The majority of bubble models describe the behavior of UCA's as single, isolated microbubbles suspended in infinite medium. Multiple scattering models such as the Independent Scattering Approximation can approximate phase velocity and attenuation for low scatterer volume fraction. However, all current models and simulations approach only describe multiple scattering and nonlinear bubble dynamics separately. Here we present an approach that combines two existing models: 1) a full-wave model that describes nonlinear propagation and scattering interactions in a heterogeneous attenuating medium and 2) a Paul-Sarkar model that describes the nonlinear interactions between an acoustic field and microbubbles. These two models were solved numerically and combined with an iterative approach. The convergence of this combined model was explored in silico for 0.5%, 1% and 2% bubble concentration by volume. The backscattering predicted by our modeling approach was verified experimentally with water tank measurements performed with a 128-element linear array transducer. An excellent agreement in terms of the fundamental and harmonic acoustic fields is shown. Additionally, our model correctly predicts the phase velocity and attenuation measured using through transmission and predicted by the Independent Scattering Approximation.
The multiple-scattering series in few-nucleon systems
Directory of Open Access Journals (Sweden)
Baru V.
2014-06-01
Full Text Available We discuss under which circumstances the resummation of the multiple-scattering series is justified from an EFT point of view. The application to πd and K̅d scattering is briefly discussed.
Multiple Scattering Methods in Casimir Calculations
Milton, Kimball A
2007-01-01
Multiple scattering formulations have been recently rediscovered as a method of studying the quantum vacuum or Casimir interactions between distinct bodies. The methods are hardly new, but increased computing power and advances in understanding allow us to extract information efficiently. Here we review the method in the simple context of $\\delta$-function potentials, so-called semitransparent bodies. (In the limit of strong coupling, a semitransparent boundary becomes a Dirichlet one.) After applying the method to rederive the Casimir force between two semitransparent plates and the Casimir self-stress on a semitransparent sphere, we obtain expressions for the Casimir energies between disjoint parallel semitransparent cylinders and between disjoint semitransparent spheres. Simplifications occur for weak and strong coupling. In particular, after performing a power series expansion in the ratio of the radii of the objects to the separation between them, we are able to sum the weak-coupling expansions exactly t...
Glucose detection in a highly scattering medium with diffuse photon-pair density wave
Directory of Open Access Journals (Sweden)
Li-Ping Yu
2017-01-01
Full Text Available We propose a novel optical method for glucose measurement based on diffuse photon-pair density wave (DPPDW in a multiple scattering medium (MSM where the light scattering of photon-pair is induced by refractive index mismatch between scatters and phantom solution. Experimentally, the DPPDW propagates in MSM via a two-frequency laser (TFL beam wherein highly correlated pairs of linear polarized photons are generated. The reduced scattering coefficient μ2s′ and absorption coefficient μ2a of DPPDW are measured simultaneously in terms of the amplitude and phase measurements of the detected heterodyne signal under arrangement at different distances between the source and detection fibers in MSM. The results show that the sensitivity of glucose detection via glucose-induced change of reduced scattering coefficient (δμ2s′ is 0.049%mM−1 in a 1% intralipid solution. In addition, the linear range of δμ2s′ vs glucose concentration implies that this DPPDW method can be used to monitor glucose concentration continuously and noninvasively subcutaneously.
Metamaterials. Invisibility cloaking in a diffusive light scattering medium.
Schittny, Robert; Kadic, Muamer; Bückmann, Tiemo; Wegener, Martin
2014-07-25
In vacuum, air, and other surroundings that support ballistic light propagation according to Maxwell's equations, invisibility cloaks that are macroscopic, three-dimensional, broadband, passive, and that work for all directions and polarizations of light are not consistent with the laws of physics. We show that the situation is different for surroundings leading to multiple light scattering, according to Fick's diffusion equation. We have fabricated cylindrical and spherical invisibility cloaks made of thin shells of polydimethylsiloxane doped with melamine-resin microparticles. The shells surround a diffusively reflecting hollow core, in which arbitrary objects can be hidden. We find good cloaking performance in a water-based diffusive surrounding throughout the entire visible spectrum and for all illumination conditions and incident polarizations of light. Copyright © 2014, American Association for the Advancement of Science.
Light scattering by a spherical particle with multiple densely packed inclusions
Institute of Scientific and Technical Information of China (English)
Sun Xian-Ming; Wang Hai-Hua; Liu Wan-Qiang; Shen Ji
2009-01-01
This paper calculates light scattering by a spherical water particle containing densely packed inclusions at a visible wavelength 0.55 μm by a combination of ray-tracing and Monte Carlo techniques. While the individual reflection and refraction events at the outer boundary of a sphere particle are considered by a ray-tracing program, the Monte Carlo routine simulates internal scattering processes. The main advantage of this method is that the shape of the particle can be arbitrary, and multiple scattering can be considered in the internal scattering processes. A dense-medium light-scattering theory based on the introduction of the static structure factor is used to calculate the phase function and asymmetry parameters for densely packed inclusions. Numerical results of the single scattering characteristics for a sphere containing multiple densely packed inclusions are given.
The influence of the nuclear medium on inclusive electron and neutrino scattering off nuclei
Buss, O; Alvarez-Ruso, L; Mosel, U
2007-01-01
We present a model for inclusive electron and neutrino scattering off nuclei paying special attention to the influence of in-medium effects on the quasi-elastic scattering and pion-production mechanisms. Our results for electron scattering off Oxygen are compared to experimental data at beam energies ranging from 0.7-1.5 GeV. The good description of electron scattering serves as a benchmark for neutrino scattering.
Optimal control of light propagation through multiple-scattering media in the presence of noise
Yilmaz, Hasan; Mosk, Allard P
2013-01-01
We study the control of coherent light propagation through multiple-scattering media in the presence of measurement noise. In our experiments, we use a two-step optimization procedure to find the optimal incident wavefront. We conclude that the degree of optimal control of coherent light propagation through a multiple-scattering medium is only determined by the number of photoelectrons detected per single speckle spot. The prediction of our model agrees well with the experimental results. Our results offer opportunities for imaging applications through scattering media such as biological tissue in the shot noise limit.
Institute of Scientific and Technical Information of China (English)
Lanqing Xu; Hui Li; Yongping Zheng
2009-01-01
Monte Carlo algorithm and Stokes-Mueller formalism are used to simulate the propagation behavior of polarized light in turbid media. The influence of single scattering and multiple scattering on backscattered Mueller matrix in turbid media is discussed. Single and double scattering photons form the major part of backscattered polarization patterns, while multiple scattering photons present more likely as background. Further quantitative analyses show that single scattering approximation and double scattering approxima tion are quite accurate when discussing the polarization patterns near the incident point.
Multiple small-angle neutron scattering studies of anisotropic materials
Allen, A J; Long, G G; Ilavsky, J
2002-01-01
Building on previous work that considered spherical scatterers and randomly oriented spheroidal scatterers, we describe a multiple small-angle neutron scattering (MSANS) analysis for nonrandomly oriented spheroids. We illustrate this with studies of the multi-component void morphologies found in plasma-spray thermal barrier coatings. (orig.)
Gamma-ray Explosion in Multiple Compton Scattering Regime
Gong, Z; Shou, Y R; Qiao, B; Bulanov, S V; Esirkepov, T Zh; Bulanov, S S; Chen, C E; He, X T; Yan, X Q
2016-01-01
Gamma-ray explosion from near critical density (NCD) target irradiated by four symmetrical imploding laser pulses is numerically investigated. With peak intensities about $10^{23}$ W/cm$^2$, the laser pulses boost electron energy through direct laser acceleration, while pushing them inward with the ponderomotive force. After backscattering with counter-propagating laser, the accelerated electron will be trapped in the optical lattice or the electromagnetic standing waves (SW) created by the coherent overlapping of the laser pulses, and meanwhile emit gamma-ray photon in Multiple Compton Scattering regime, where electron acts as a medium to transfer energy from laser to gamma-ray. The energy conversion rate from laser pulses to gamma-ray can be as high as around 50\\%. It may become one of the most efficient gamma-ray sources in laboratory.
Multiple magnetic scattering in small-angle neutron scattering of Nd-Fe-B nanocrystalline magnet.
Ueno, Tetsuro; Saito, Kotaro; Yano, Masao; Ito, Masaaki; Shoji, Tetsuya; Sakuma, Noritsugu; Kato, Akira; Manabe, Akira; Hashimoto, Ai; Gilbert, Elliot P; Keiderling, Uwe; Ono, Kanta
2016-06-20
We have investigated the influence of multiple scattering on the magnetic small-angle neutron scattering (SANS) from a Nd-Fe-B nanocrystalline magnet. We performed sample-thickness- and neutron-wavelength-dependent SANS measurements, and observed the scattering vector dependence of the multiple magnetic scattering. It is revealed that significant multiple scattering exists in the magnetic scattering rather than the nuclear scattering of Nd-Fe-B nanocrystalline magnet. It is considered that the mean free path of the neutrons for magnetic scattering is rather short in Nd-Fe-B magnets. We analysed the SANS data by the phenomenological magnetic correlation model considering the magnetic microstructures and obtained the microstructural parameters.
Experimental study of multiple scattering in anisotropic titanium alloys
Baelde, Aurelien; Laurent, Jérôme; Coulette, Richard; Khalifa, Warida Ben; Duclos, Daniel; Jenson, Frédéric; Fink, Mathias; Prada, Claire
2017-02-01
Ultrasonic testing of jet engine titanium alloys is of high importance for the aircraft manufacturing industry. The quality of ultrasonic non-destructive testing is severely impacted by the titanium complex microstructure. These alloys have been extensively studied and single scattering models are now well known and implemented in ultrasonic propagation simulators. In addition, titanium billets and forged parts have been known to exhibit a highly anisotropic microstructure. We studied ultrasonic wave scattering in Ti17 forged disk, through statistical analysis of the backscattered noise generated by the microstructure. More specifically, we focused on the quantification of multiple scattering relative to single scattering in the backscattered wave. To that end, we used the full matrix capture acquisition with a linear transducer array. Two phenomena were used to quantify the proportion of single scattering with respect to multiple scattering. The first is the coherent backscattering effect, used as a binary indicator of multiple scattering. The second is a repurposed version of the multiple scattering filter, recently developed on random rod forest and applied on Inconel alloys. With these methods, significant level of multiple scattering was consistently measured in Ti17 forged disks, showing that ultrasonic testing could be enhanced by filtering the multiple scattering contribution.
Non-line-of-sight ultraviolet single-scatter propagation model in random turbulent medium.
Xiao, Houfei; Zuo, Yong; Wu, Jian; Li, Yan; Lin, Jintong
2013-09-01
Non-line-of-sight (NLOS) ultraviolet communication (UVC) uses the atmosphere as a propagation medium. In previous literature, various scatter propagation models have been derived based on the premise that atmospheric turbulence was ignored and the atmosphere was considered as a turbid medium, also called random scatterers. In this Letter, a NLOS single-scatter propagation model is proposed to describe the singly scattered radiation in a turbulent medium, also called a random continuum, such as the clear atmosphere. The model is established based on the relationship between the scattered power and the characteristics of the random turbulent medium. The scattering cross section is further investigated in terms of different correlation distances and wavelengths. The received power dependence for NLOS UVC is also analyzed for different factors, including refractive-index structure parameter and transceiver range.
Path length distribution of multiple-scattered photons by low coherence Doppler interferometry
Petoukhova, Anna; Steenbergen, Wiendelt; de Mul, F.F.M.; Tuchin, V.V.; Izatt, J.A.; Fujimoto, J.G.
2002-01-01
We report results of measurements by low coherence Doppler interferometry of the path length distribution of photons undergoing multiple scattering in a highly turbid medium. We use a Mach-Zehnder interferometer with multimode graded index fibers and a superluminescent diode as light source. The pat
Observation of spatial quantum correlations induced by multiple scattering of nonclassical light
DEFF Research Database (Denmark)
Smolka, Stephan; Huck, Alexander; Andersen, Ulrik Lund;
2009-01-01
We present the experimental realization of spatial quantum correlations of photons that are induced by multiple scattering of squeezed light. The quantum correlation relates photons propagating along two different light paths through the random medium and is infinite in range. Both positive...
Multiple scattering of polarized light: influence of absorption.
Hohmann, A; Voit, F; Schäfer, J; Kienle, A
2014-06-07
This work continues previous research about multiple scattering of polarized light propagation in turbid media, putting emphasis on the imaginary part of the scatterers' complex refractive index. The whole angle-dependent Müller matrix is evaluated by comparing results of a polarization sensitive radiative transfer solution to Maxwell theory. Turbid media of defined scatterer concentrations are modelled in three dimensions by sphere ensembles kept inside a cubic or spherical simulation volume. This study addresses the impact of absorption on polarization characteristics for selected media from low to high absorption. Besides that, effects caused by multiple and dependent scattering are shown for increasing volume concentration. In this context some unique properties associated with multiple scattering and absorption are pointed out. Further, scattering results in two dimensions are compared for examples of infinite parallel cylinders of high absorption and perpendicularly incident plane waves.
Li, Jia; Chen, Feinan; Chang, Liping
2016-10-17
Within the validity of the first-order Born approximation, expressions are derived for the correlation between intensity fluctuations (CIF) of an electromagnetic plane wave scattered from a spatially quasi-homogeneous (QH), anisotropic medium. Upon establishing the correlation matrix of the scattering potential of the medium, we show that the CIF is the summation of Fourier transforms of the strengths and normalized correlation coefficients (NCCs) of the scattering potential matrix. Numerical results reveal that the CIF is susceptible to the effective width and correlation length of the medium, and degree of polarization of the incident electromagnetic wave. Our study not only extends the current knowledge of the CIF of a scattered field but also provides an important reference to the study of high-order intensity correlations of light scattered from a spatially anisotropic medium.
Meteor forward scattering at multiple frequencies
Nedeljkovic, Sasa
2006-08-01
Meteor forward scattering is a well known method of detecting meteors using a radio telescope to receive signals from distant transmitters scattered from a meteor trail. The traditional way of performing the meteor forward scattering is to tune the receiver to some particular frequency to match a distant transmitter and wait for reflected signals. In this paper I will show how new technologies can be used to make a simpler digital radio telescope capable of analyzing broadband spectra from 0 to 250 MHz. Such spectra contain information about several reflections on a single meteor, which can be enough to calculate the meteor's kinetic parameters.
Holographic imaging through a scattering medium by diffuser-aided statistical averaging.
Purcell, Michael J; Kumar, Manish; Rand, Stephen C; Lakshminarayanan, Vasudevan
2016-07-01
We introduce a practical digital holographic method capable of imaging through a diffusive or scattering medium. The method relies on statistical averaging from a rotating ground glass diffuser to negate the adverse effects caused by speckle introduced by a static diffuser or scattering medium. In particular, a setup based on Fourier transform holography is used to show that an image can be recovered after scattering by introducing an additional diffuser in the optical setup. This method is capable of recovering object information from behind a scattering layer in biomedical or military imaging applications.
Holographic imaging through a scattering medium by diffuser-aided statistical averaging
Purcell, Michael J; Rand, Stephen C; Lakshminarayanan, Vasudevan
2016-01-01
We introduce a practical digital holographic method capable of imaging through a diffusive or scattering medium. The method relies on statistical averaging from a rotating ground glass diffuser to negate the adverse effects caused by speckle introduced by a first, static diffuser or scattering medium. In particular, a setup based on Fourier transform holography is used to show that an image can be recovered after scattering by introducing an additional diffuser in the optical setup. This method is capable of recovering object information from behind a scattering layer in biomedical or military imaging applications.
Wang, Tao; Jiang, Zhenfei; Ji, Xiaoling; Zhao, Daomu
2016-04-01
Spectral shifts and spectral switches of a polychromatic electromagnetic light wave on scattering from an anisotropic semisoft boundary medium are discussed. It is shown that both the property of the incident field and the character of the scattering medium play roles in the change of the spectrum of the far-zone scattered field. It is also shown that the distribution of the far-zone scattered spectrum, including the magnitude of the spectral shift and the direction at which the spectral switch occurs, is rotationally nonsymmetric.
Pions in the nuclear medium and Drell-Yan scattering
Dieperink, AEL; Korpa, CL
1997-01-01
We investigate the modification of the pion cloud in the nuclear medium and its effect on the nuclear Drell-Yan process. The pion's in-medium self-energy is calculated in a self-consistent delta-hole model, with particle-hole contributions also included. Both the imaginary and real parts of the pion
Institute of Scientific and Technical Information of China (English)
Ren Xin-Cheng; Guo Li-Xin
2008-01-01
Electromagnetic scattering from a rough surface of layered medium is investigated, and the formulae of the scattering coefficients for different polarizations are derived using the small perturbation method. A rough surface with exponential correlation function is presented for describing a rough soil surface of layered medium, the formula of its scattering coefficient is derived by considering the spectrum of the rough surface with exponential correlation function; the curves of the bistatic scattering coefficient of HH polarization with variation of the scattering angle are obtained by numerical calculation. The influence of the permittivity of layered medium, the mean layer thickness of intermediate medium, the roughness surface parameters and the frequency of the incident wave on the bistatic scattering coefficient is discussed. Numerical results show that the influence of the permittivity of layered medium, the mean layer thickness of intermediate medium, the rms and the correlation length of the rough surface, and the frequency of the incident wave on the bistatic scattering coefficient is very complex.
Scatterer localization using a left-handed medium.
Karkashadze, David; Fernández, Juan Pablo; Shubitidze, Fridon
2009-06-01
This paper explores the possibility of using the focusing property of left-handed materials to estimate the location of a visually obscured target. The field scattered by the target and measured on a surface can be considered as incident upon a left-handed half-space and should converge to a point resembling the mirror image of the scatterer's location. The results are obtained using the method of auxiliary sources as adapted to double-negative media. Two-dimensional scattering is considered, either from a single object or from several targets, using pointlike and Gaussian sources of illumination. The method gives reasonable results when the sizes of the scatterers are comparable to the wavelength.
A New Glauber Theory based on Multiple Scattering Theory
Yahiro, Masanobu; Ogata, Kazuyuki; Kawai, Mitsuji
2008-01-01
Glauber theory for nucleus-nucleus scattering at high incident energies is reformulated so as to become applicable also for the scattering at intermediate energies. We test validity of the eikonal and adiabatic approximations used in the formulation, and discuss the relation between the present theory and the conventional Glauber calculations with either the empirical nucleon-nucleon profile function or the modified one including the in-medium effect.
A model for multiple scattering in GEANT4
Urbán, László
2006-01-01
We present a model to simulate the multiple scattering of charged particles in matter. The model is based on Lewis theory; it does not use the Moliere formalism. It simulates the scattering of a charged particle after a given step, computes the path length correction and the lateral displacement as well. This model is used in GEANT4.
Study of multiple scattering effects in heavy ion RBS
Energy Technology Data Exchange (ETDEWEB)
Fang, Z.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics
1996-12-31
Multiple scattering effect is normally neglected in conventional Rutherford Backscattering (RBS) analysis. The backscattered particle yield normally agrees well with the theory based on the single scattering model. However, when heavy incident ions are used such as in heavy ion Rutherford backscattering (HIRBS), or the incident ion energy is reduced, multiple scattering effect starts to play a role in the analysis. In this paper, the experimental data of 6MeV C ions backscattered from a Au target are presented. In measured time of flight spectrum a small step in front of the Au high energy edge is observed. The high energy edge of the step is about 3.4 ns ahead of the Au signal which corresponds to an energy {approx} 300 keV higher than the 135 degree single scattering energy. This value coincides with the double scattering energy of C ion undergoes two consecutive 67.5 degree scattering. Efforts made to investigate the origin of the high energy step observed lead to an Monte Carlo simulation aimed to reproduce the experimental spectrum on computer. As a large angle scattering event is a rare event, two consecutive large angle scattering is extremely hard to reproduce in a random simulation process. Thus, the simulation has not found a particle scattering into 130-140 deg with an energy higher than the single scattering energy. Obviously faster algorithms and a better physical model are necessary for a successful simulation. 16 refs., 3 figs.
Multiple Scattering: Dispersion, Temperature Dependence, and Annular Pistons
Milton, Kimball A; Parashar, Prachi; Cavero-Pelaez, Ines; Brevik, Iver; Ellingsen, Simen A
2010-01-01
We review various applications of the multiple scattering approach to the calculation of Casimir forces between separate bodies, including dispersion, wedge geometries, annular pistons, and temperature dependence. Exact results are obtained in many cases.
MULTIPLE SCATTERING IN THE EXAFS OF CALCIUM PHOSPHATES
1986-01-01
Analysis of the EXAFS spectra of hydroxyapatite, brushite and monetite, recorded above the calcium K edge, requires the inclusion of multiple scattering by phosphorus atoms at 0.37 nm, from calcium. If multiple scattering is not included, some variable parameters acquire physically unreasonable values. Atomic radii never had to be varied by more than 0.01 nm from their values in the accepted crystal structures.
Multiple scattering approach to X-ray absorption spectroscopy
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
In this paper we present the state of the art of the theoretical background needed for analyzing X-ray absorption spectra in the whole energy range. The multiple-scattering (MS) theory is presented in detail with some applications on real systems. We also describe recent progress in performing geometrical fitting of the XANES (X-ray absorption near-edge structure) energy region and beyond using a full multiple-scattering approach.
Algebraic-Eikonal approach to medium energy proton scattering from odd-mass nuclei
Bijker, R
1995-01-01
We extend the algebraic-eikonal approach to medium energy proton scattering from odd-mass nuclei by combining the eikonal approximation for the scattering with a description of odd-mass nuclei in terms of the interacting boson-fermion model. We derive closed expressions for the transition matrix elements for one of the dynamical symmetries and discuss the interplay between collective and single-particle degrees of freedom in an application to elastic and inelastic proton scattering from ^{195}Pt.
Forward scattering of meteors at multiple frequencies
Nedeljkovic, S.; Netterfield, C. B.
2006-05-01
Forward scattering of meteors is a method of meteor detection using a radio receiver to detect signals coming from the transmitters not in line-of-sight. When a meteoroid enters the atmosphere an ionized trail which can reflect radio waves is created. If the meteor, the transmitter and the receiver are in "good" geometrical alignment such that coherent scattering is possible, the receiver will be able to detect a signal reflected from the meteor. A digital radio spectrometer working between 50 and 150MHz and connected to a small wide-frequency, wide-beam antenna can be used as a detector. Its spectral resolution is better than 50kHz and able to resolve individual FM radio and TV stations. In this paper we shall give an overview of the apparatus used to detect meteors at FM frequencies. We will also explain how we can extract the kinetic parameters of the meteoroid. Some preliminary results will be presented.
Method for measuring multiple scattering corrections between liquid scintillators
Verbeke, J. M.; Glenn, A. M.; Keefer, G. J.; Wurtz, R. E.
2016-07-01
A time-of-flight method is proposed to experimentally quantify the fractions of neutrons scattering between scintillators. An array of scintillators is characterized in terms of crosstalk with this method by measuring a californium source, for different neutron energy thresholds. The spectral information recorded by the scintillators can be used to estimate the fractions of neutrons multiple scattering. With the help of a correction to Feynman's point model theory to account for multiple scattering, these fractions can in turn improve the mass reconstruction of fissile materials under investigation.
A new screening length for small angle multiple scattering
Energy Technology Data Exchange (ETDEWEB)
Ikegami, Seiji, E-mail: double1892@gmail.com
2013-09-15
A new screening length formulation that incorporates the charge state of the projectile is applied to multiple scattering. The present screening length is derived from an interatomic potential that accounts for electron–electron, electron–nuclear, and nuclear–nuclear interactions using the Thomas–Fermi–Moliere potential. We examined the charge state effect on multiple scattering angular distributions. We successfully estimate the charge state effects and predict angular distributions. The present screening length is compared with many low energy ion scattering experiments and with O’Connor–Biersack prediction values.
Multiple scattering induced negative refraction of matter waves
Pinsker, Florian
2016-01-01
Starting from fundamental multiple scattering theory it is shown that negative refraction indices are feasible for matter waves passing a well-defined ensemble of scatterers. A simple approach to this topic is presented and explicit examples for systems of scatterers in 1D and 3D are stated that imply negative refraction for a generic incoming quantum wave packet. Essential features of the effective scattering field, densities and frequency spectrum of scatterers are considered. Additionally it is shown that negative refraction indices allow perfect transmission of the wave passing the ensemble of scatterers. Finally the concept of the superlens is discussed, since it is based on negative refraction and can be extended to matter waves utilizing the observations presented in this paper which thus paves the way to ‘untouchable’ quantum systems in analogy to cloaking devices for electromagnetic waves. PMID:26857266
Evaluation of radar multiple scattering effects in Cloudsat configuration
Directory of Open Access Journals (Sweden)
A. Battaglia
2007-01-01
Full Text Available MonteCarlo simulations have been performed to evaluate the importance of multiple scattering effects in co- and cross-polar radar returns for 94 GHz radars in Cloudsat and airborne configurations. Thousands of vertically structured profiles derived from some different cloud resolving models are used as a test-bed. Mie theory is used to derive the single scattering properties of the atmospheric hydrometeors. Multiple scattering effects in the co-polar channel (reflectivity enhancement are particularly elusive, especially in airborne configuration. They can be quite consistent in satellite configurations, like CloudSat, especially in regions of high attenuation and in the presence of highly forward scattering layers associated with snow and graupel particles. When the cross polar returns are analysed [but note that CloudSat does not measure any linear depolarization ratio (LDR hereafter], high LDR values appear both in space and in airborne configurations. The LDR signatures are footprints of multiple scattering effects; although depolarization values as high as −5 dB can be generated including non-spherical particles in single scattering modelling, multiple scattering computations can produce values close to complete depolarization (i.e. LDR=0 dB. Our simulated LDR profiles from an air-borne platform well reproduce, in a simple frame, some experimental observations collected during the Wakasa Bay experiment. Since LDR instrumental uncertainties were not positively accounted for during that experiment, more focused campaigns with air-borne polarimetric radar are recommended. Multiple scattering effects can be important for CloudSat applications like rainfall and snowfall retrievals since single scattering based algorithms will be otherwise burdened by positive biases.
Hadronic scattering amplitudes medium-energy constraints on asymptotic behaviour
Cudell, J R; Gauron, P; Kang, K; Kuyanov, Yu V; Lugovsky, S B; Nicolescu, Basarab; Tkachenko, N P; Kuyanov, Yu. V.
2002-01-01
We consider several classes of analytic parametrisations of hadronic scattering amplitudes, and compare their predictions to all available forward data (p p, pbar p, pi p, K p, gamma p, gamma gamma, Sigma p). Although these parametrisations are very close for sqrt(s) > 9 GeV, it turns out that they differ markedly at low energy, where a universal pomeron term ~log^2(s) enables one to extend the fit down to sqrt(s)=4 GeV.
Multiple scattering and $p_t$-broadening at RHIC energies
Papp, G; Fái, G; Lévai, Peter; Zhang, Y
2002-01-01
In ultrarelativistic heavy-ion collisions, in the 2 GeV$
About multiple scattering of high energy protons in crystal deflectors
Energy Technology Data Exchange (ETDEWEB)
Taratin, A.M., E-mail: alexander.taratin@cern.ch [Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russian Federation); Scandale, W. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Laboratoire de l’Accelerateur Lineaire (LAL), Universite Paris Sud Orsay, Orsay (France); INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy)
2015-07-15
The process of multiple scattering of high energy protons in a silicon crystal at its amorphous orientation was studied by simulation of proton trajectories in the model of binary collisions and by a straight simulation of the sequences of proton collisions with atoms when their impact parameters are randomly and uniformly distributed on the symmetry cell for a given crystallography direction. The value of the RMS deflection of multiple scattering obtained by the simulation is in a good agreement with the experiment and more than 15% larger than it follows from the Moliere theory. The obtained RMS deflection used in the Gaussian approach of multiple scattering well describes dechanneling of protons in the frame of the planar potential model. Different number of proton collisions with atoms occurs along the same crystal length for different crystal orientations. However, the change of the collision number is compensated by the corresponding change of the mean square deflection in a single collision. Therefore, multiple scattering is the same for different crystal orientations. The generator of multiple scattering for amorphous crystal orientations was proposed.
Analysis of polarized pulse propagation through one-dimensional scattering medium
Zhang, Yong; Yao, Feng-Ju; Xie, Ming; Yi, Hong-Liang
2017-08-01
This paper analyzes the polarized light propagation in a one-dimensional scattering medium with the upper surface subjected to an oblique incident short-pulsed laser beam using the natural element method (NEM). The NEM discretization scheme for the transient vector radiative transfer equation (TVRTE) is presented in detail. The accuracy of the natural element method for transient vector radiative transfer in the scattering medium is assessed. Numerical results show that the NEM is accurate, and effective in solving transient polarized radiative problems. We examine a square short-pulsed laser transport firstly in the atmosphere with Mie scattering and then within aerosol scattering medium. We then investigate the transient polarized radiative transfer problem in the atmosphere-ocean system. The time-resolved signals and the polarization state of the Stokes vector are presented and analyzed. It is found that the scattering types of the medium make greatly influence on the transient transportation of the polarized light. Critically, the polarization states of the backward and forward scattered photons show significantly different time varying trends. For the two-layer system with dissimilar refractive index distributions, due to the total-reflection effect, the existence of a Fresnel interface significantly changes the polarization state of the light, and discontinuous distribution features are observed on the interface.
Efficient light propagation for multiple anisotropic volume scattering
Energy Technology Data Exchange (ETDEWEB)
Max, N. [Lawrence Livermore National Lab., CA (United States)]|[California Univ., Davis, CA (United States)
1993-12-01
Realistic rendering of participating media like clouds requires multiple anisotropic light scattering. This paper presents a propagation approximation for light scattered into M direction bins, which reduces the ``ray effect`` problem in the traditional ``discrete ordinates`` method. For a volume of n{sup 3} elements, it takes O(M n{sup 3} log n + M{sup 2} n{sup 3}) time and O(M n{sup 3}) space.
Numerical modelling of multiple scattering between two elastical particles
DEFF Research Database (Denmark)
Bjørnø, Irina; Jensen, Leif Bjørnø
1998-01-01
in suspension have been studied extensively since Foldy's formulation of his theory for isotropic scattering by randomly distributed scatterers. However, a number of important problems related to multiple scattering are still far from finding their solutions. A particular, but still unsolved, problem...... is higher than 20 g/l of sand particles. This paper reports an attempt to illuminate and to solve the proximity threshold question, by an in-depth numerical study of the interaction of ultrasonic signals with two canonically shaped elastic particles. Introductory experimental results seem to create evidence...
Nonlinear Propagation of Coupling Optical Pulse under Compton Scattering in Laser Medium
Institute of Scientific and Technical Information of China (English)
HAO Dong-shan; ZHANG Xiao-fu
2006-01-01
After considering Kerr nonlinear effect,group velocity dispersion of host and gain distribution of active particle in laser amplifying medium,a basic equation describing propagation of the coupling optical pulse under the multi-photon nonlinear Compton scattering in the laser amplifying medium has been deduced. Besides,the profile and power spectrum of a picosecond-level super-Gaussian coupling pulse in the laser amplifying medium have been discussed when its central frequency coincides with the gain peak frequency of the laser amplifying medium.
Dirichlet-to-Neumann boundary conditions for multiple scattering problems
Grote, Marcus J.; Kirsch, Christoph
2004-12-01
A Dirichlet-to-Neumann (DtN) condition is derived for the numerical solution of time-harmonic multiple scattering problems, where the scatterer consists of several disjoint components. It is obtained by combining contributions from multiple purely outgoing wave fields. The DtN condition yields an exact non-reflecting boundary condition for the situation, where the computational domain and its exterior artificial boundary consist of several disjoint components. Because each sub-scatterer can be enclosed by a separate artificial boundary, the computational effort is greatly reduced and becomes independent of the relative distances between the different sub-domains. The DtN condition naturally fits into a variational formulation of the boundary-value problem for use with the finite element method. Moreover, it immediately yields as a by-product an exact formula for the far-field pattern of the scattered field. Numerical examples show that the DtN condition for multiple scattering is as accurate as the well-known DtN condition for single scattering problems [J. Comput. Phys. 82 (1989) 172; Numerical Methods for Problems in Infinite Domains, Elsevier, Amsterdam, 1992], while being more efficient due to the reduced size of the computational domain.
Spatio-temporal focusing of an ultrafast pulse through a multiply scattering medium.
McCabe, David J; Tajalli, Ayhan; Austin, Dane R; Bondareff, Pierre; Walmsley, Ian A; Gigan, Sylvain; Chatel, Béatrice
2011-08-23
Pulses of light propagating through multiply scattering media undergo complex spatial and temporal distortions to form the familiar speckle pattern. There is much current interest in both the fundamental properties of speckles and the challenge of spatially and temporally refocusing behind scattering media. Here we report on the spatially and temporally resolved measurement of a speckle field produced by the propagation of an ultrafast optical pulse through a thick strongly scattering medium. By shaping the temporal profile of the pulse using a spectral phase filter, we demonstrate the spatially localized temporal recompression of the output speckle to the Fourier-limit duration, offering an optical analogue to time-reversal experiments in the acoustic regime. This approach shows that a multiply scattering medium can be put to profit for light manipulation at the femtosecond scale, and has a diverse range of potential applications that includes quantum control, biological imaging and photonics.
Deharak, B. A.; Savich, J. L.; Roberts, H. M.; Brown, E. G.; McGill, M. R.; Kim, B. N.; Weaver, C. M.; Martin, N. L. S.
2016-05-01
We have conducted a series of Monte Carlo simulations of laser assisted free-free scattering experiments. The simulations make use of Kroll-Watson approximation to account for the effects of the laser field on the scattering process. The parameters for these simulations are believed to mimic the experimental conditions of the work reported by Wallbank and Holmes, particularly the target number density. The simulations account for the effects multiple scattering (i.e., the scattering of a single incident electron from multiple target atoms). We present a comparison of the results of these simulations to the experimental results of Wallbank and Holmes. This work was supported by the National Science Foundation under Grants Nos. PHY-0855040 (NLSM) and PHY-1402899 (BAd).
An empirical correction for moderate multiple scattering in super-heterodyne light scattering
Botin, Denis; Mapa, Ludmila Marotta; Schweinfurth, Holger; Sieber, Bastian; Wittenberg, Christopher; Palberg, Thomas
2017-05-01
Frequency domain super-heterodyne laser light scattering is utilized in a low angle integral measurement configuration to determine flow and diffusion in charged sphere suspensions showing moderate to strong multiple scattering. We introduce an empirical correction to subtract the multiple scattering background and isolate the singly scattered light. We demonstrate the excellent feasibility of this simple approach for turbid suspensions of transmittance T ≥ 0.4. We study the particle concentration dependence of the electro-kinetic mobility in low salt aqueous suspension over an extended concentration regime and observe a maximum at intermediate concentrations. We further use our scheme for measurements of the self-diffusion coefficients in the fluid samples in the absence or presence of shear, as well as in polycrystalline samples during crystallization and coarsening. We discuss the scope and limits of our approach as well as possible future applications.
Lechleiter, Armin; Nguyen, Dinh Liem
2010-01-01
Scattering of acoustic waves from an inhomogeneous medium can be described by the Lippmann-Schwinger integral equation. For scattering problems in free space, Vainikko proposed a fast spectral solution method that exploits the convolution structure of this equation's integral operator by using the fast Fourier transform. In a planar 3--dimensional waveguide, the integral operator of the Lippmann-Schwinger integral equation fails to be a convolution. In this paper, we show that the separable s...
A study of nondiffracting Lommel beams propagating in a medium containing spherical scatterers
Belafhal, A.; Ez-zariy, L.; Hricha, Z.
2016-11-01
By means of the expansion of the nondiffracting beams on plane waves with help of the Whittaker integral, an exact analytical expression of the far-field form function of the scattering of the acoustic and optical nondiffracting Lommel beams propagating in a medium containing spherical particles, considered as rigid and single spheres, is investigated in this work. The form function of the scattering of the high order Bessel beam by a rigid and isolated sphere is deduced, from our finding, as a special case. The effects of the wave number-sphere radius product (ka) , the polar angle (φ) , the propagation half-cone angle (β) and the scattering angle (θ) on the far-field form function of the scattered wave have been analyzed and discussed numerically. The numerical results show that the illumination of a rigid sphere by Lommel beams produces asymmetrical scattering.
Ma, L. X.; Tan, J. Y.; Zhao, J. M.; Wang, F. Q.; Wang, C. A.
2017-01-01
The radiative transfer equation (RTE) has been widely used to deal with multiple scattering of light by sparsely and randomly distributed discrete particles. However, for densely packed particles, the RTE becomes questionable due to strong dependent scattering effects. This paper examines the accuracy of RTE by comparing with the exact electromagnetic theory. For an imaginary spherical volume filled with randomly distributed, densely packed spheres, the RTE is solved by the Monte Carlo method combined with the Percus-Yevick hard model to consider the dependent scattering effect, while the electromagnetic calculation is based on the multi-sphere superposition T-matrix method. The Mueller matrix elements of the system with different size parameters and volume fractions of spheres are obtained using both methods. The results verify that the RTE fails to deal with the systems with a high-volume fraction due to the dependent scattering effects. Apart from the effects of forward interference scattering and coherent backscattering, the Percus-Yevick hard sphere model shows good accuracy in accounting for the far-field interference effects for medium or smaller size parameters (up to 6.964 in this study). For densely packed discrete spheres with large size parameters (equals 13.928 in this study), the improvement of dependent scattering correction tends to deteriorate. The observations indicate that caution must be taken when using RTE in dealing with the radiative transfer in dense discrete random media even though the dependent scattering correction is applied.
Multiple photon effects in $pp$ scattering at SSC energies
Delaney, D B; Shio, C; Siopsis, G; Ward, B F L
1992-01-01
The Monte Carlo program SSCYFS2 is used in conjunction with available parton distribution functions to calculate the effects of multiple photon radiation on pp scattering at SSC energies. Effects relevant to precision SSC physics such as Higgs discovery and exploration are illustrated.
Quantum noise memory effect of multiple scattered light
Lodahl, P
2005-01-01
We investigate frequency correlations in multiple scattered light that are present in the quantum fluctuations. The memory effect for quantum and classical noise is compared, and found to have markedly different frequency scaling, which was confirmed in a recent experiment. Furthermore, novel mesoscopic correlations are predicted that depend on the photon statistics of the incoming light.
Geant4 models for simulation of multiple scattering
Ivanchenko, V N; Maire, M; Urban, L
2010-01-01
Recent progress in development of single and multiple scattering models within the Geant4 toolkit is presented. Different options available to users are discussed. The comparisons with the data are shown. The trade of precision versus CPU performance is discussed with the focus on LHC detectors simulation
Improved Monte Carlo model for multiple scattering calculations
Institute of Scientific and Technical Information of China (English)
Weiwei Cai; Lin Ma
2012-01-01
The coupling between the Monte Carlo (MC) method and geometrical optics to improve accuracy is investigated.The results obtained show improved agreement with previous experimental data,demonstrating that the MC method,when coupled with simple geometrical optics,can simulate multiple scattering with enhanced fidelity.
Berginc, G.
2016-08-01
In this paper, we consider the coherent component of the electromagnetic wave field inside random media. The subject of our interest concerns a random medium, consisting of a statistical ensemble of different scattering species and artificial material structures developed on base of dielectric or metallic resonant or non-resonant particles. The starting point of our theory is the multiple scattering theory, the averaged electric field satisfies a Dyson equation with a mass operator related to the effective dielectric permittivity of the homogenized structure. Quantum multiple scattering theory has been transposed into this electromagnetic case. We give a formal solution for the mass operator by introducing the T-matrix formalism. We show that the T-matrix satisfies a Lippman-Schwinger equation. Then, we introduce the Quasi-Crystalline Coherent Potential Approximation (QC-CPA), which takes into account the correlation between the particles with a pair-distribution function. The mass operator includes geometric effects, caused by resonant behavior due to the shape and size of particles, cluster effects because of correlations between particles. Significant modifications of particle scattering properties can be observed.
Influence on Atomic Inversion Evolution in Medium System from Compton Scattering
Institute of Scientific and Technical Information of China (English)
HAO Xiao-fei; HAO Dong-shan
2008-01-01
In Jaynes-Cummings model, by using the modulation of the coupling coefficient formed by the atom, medium and scattering optical, atomic inversion evolution of arbitrary forms has been worked out. Its feasibility has been proved, and the curvature of the atomic inversion evolution of the arbitrary forms is obtained. It announces that the atom and coupling medium system are to express the operators of the atom and optical field quantum in Jaynes-Cummings model. These operators can express arbitrary medium system. In these systems, the coupling coefficient can be changed and exactly controlled in the longer coherent times.
Fourier domain multispectral multiple scattering low coherence interferometry.
Matthews, Thomas E; Giacomelli, Michael G; Brown, William J; Wax, Adam
2013-12-01
We have implemented multispectral multiple scattering low coherence interferometry (ms2/LCI) with Fourier domain data collection. The ms2/LCI system is designed to localize features with spectroscopic contrast with millimeter resolution up to 1 cm deep in scattering samples by using photons that have undergone multiple low-angle (forward) scattering events. Fourier domain detection both increases the data acquisition speed of the system and gives access to rich spectroscopic information, compared to the previous single channel, time-domain implementation. Separate delivery and detection angular apertures reduce collection of the diffuse background signal in order to isolate localized spectral features from deeper in scattering samples than would be possible with traditional spectroscopic optical coherence tomography. Light from a supercontinuum source is used to acquire absorption spectra of chromophores in the visible range within a tissue-like scattering phantom. An intensity modulation and digital lock-in detection scheme is implemented to mitigate relative intensity and spectral noise inherent in supercontinuum sources. The technical parameters of the system and comparative analysis are presented.
Evaluation of Influence of Multiple Scattering Effect in Light-Scattering-Based Applications
Institute of Scientific and Technical Information of China (English)
XU Sheng-Hua; SUN Zhi-Wei
2007-01-01
The extinction cross sections of a system containing two particles are calculated by the T-matrix method, and the results are compared with those of two single particles with single-scattering approximation. The necessity of the correction of the refractive indices of water and polystyrene for different incident wavelengths is particularly addressed in the calculation. By this means, the volume fractions allowed for certain accuracy requirements of single-scattering approximation in the light scattering experiment can be evaluated. The volume fractions calculated with corrected refractive indices are compared with those obtained with fixed refractive indices which have been rather commonly used, showing that fixed refractive indices may cause significant error in evaluating multiple scattering effect. The results also give a simple criterion for selecting the incident wavelength and particle size to avoid the 'blind zone' in the turbidity measurement, where the turbidity change is insensitive to aggregation of two particles.
Doronin, Alexander; Tchvialeva, Lioudmila; Markhvida, Igor; Lee, Tim K.; Meglinski, Igor
2016-07-01
In the framework of further development of a unified computational tool for the needs of biomedical optics, we introduce an electric field Monte Carlo (MC) model for simulation of backscattering of coherent linearly polarized light from a turbid tissue-like scattering medium with a rough surface. We consider the laser speckle patterns formation and the role of surface roughness in the depolarization of linearly polarized light backscattered from the medium. The mutual phase shifts due to the photons' pathlength difference within the medium and due to reflection/refraction on the rough surface of the medium are taken into account. The validation of the model includes the creation of the phantoms of various roughness and optical properties, measurements of co- and cross-polarized components of the backscattered/reflected light, its analysis and extensive computer modeling accelerated by parallel computing on the NVIDIA graphics processing units using compute unified device architecture (CUDA). The analysis of the spatial intensity distribution is based on second-order statistics that shows a strong correlation with the surface roughness, both with the results of modeling and experiment. The results of modeling show a good agreement with the results of experimental measurements on phantoms mimicking human skin. The developed MC approach can be used for the direct simulation of light scattered by the turbid scattering medium with various roughness of the surface.
Charged Particle Multiplicities in Deep Inelastic Scattering at HERA
Aïd, S; Andreev, V; Andrieu, B; Appuhn, R D; Babaev, A; Ban, Y; Baranov, P S; Barrelet, E; Barschke, R; Bartel, Wulfrin; Barth, Monique; Bassler, U; Beck, H P; Behrend, H J; Belousov, A; Berger, C; Bernardi, G; Bertrand-Coremans, G H; Besançon, M; Beyer, R; Biddulph, P; Bispham, P; Bizot, J C; Blobel, Volker; Borras, K; Botterweck, F; Boudry, V; Braemer, A; Braunschweig, W; Brisson, V; Bruel, P; Bruncko, Dusan; Brune, C R; Buchholz, R; Buniatian, A Yu; Burke, S; Burton, M; Bähr, J; Büngener, L; Bürger, J; Büsser, F W; Calvet, D; Campbell, A J; Carli, T; Charlet, M; Chechelnitskii, S; Chernyshov, V; Clarke, D; Clegg, A B; Clerbaux, B; Cocks, S P; Contreras, J G; Cormack, C; Coughlan, J A; Courau, A; Cousinou, M C; Cozzika, G; Criegee, L; Cussans, D G; Cvach, J; Dagoret, S; Dainton, J B; Dau, W D; Daum, K; David, M; Davis, C L; De Wolf, E A; Delcourt, B; Di Nezza, P; Dirkmann, M; Dixon, P; Dlugosz, W; Dollfus, C; Dowell, John D; Dreis, H B; Droutskoi, A; Duhm, H; Dünger, O; Ebert, J; Ebert, T R; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, Franz; Eisenhandler, Eric F; Ellison, R J; Elsen, E E; Erdmann, M; Erdmann, W; Evrard, E; Fahr, A B; Favart, L; Fedotov, A; Feeken, D; Felst, R; Feltesse, Joel; Ferencei, J; Ferrarotto, F; Flamm, K; Fleischer, M; Flieser, M; Flügge, G; Fomenko, A; Fominykh, B A; Formánek, J; Foster, J M; Franke, G; Fretwurst, E; Gabathuler, Erwin; Gabathuler, K; Gaede, F; Garvey, J; Gayler, J; Gebauer, M; Genzel, H; Gerhards, R; Glazov, A; Goerlach, U; Gogitidze, N; Goldberg, M; Goldner, D; Golec-Biernat, Krzysztof J; González-Pineiro, B; Gorelov, I V; Grab, C; Greenshaw, T J; Griffiths, R K; Grindhammer, G; Gruber, A; Gruber, C; Grässler, Herbert; Grässler, R; Görlich, L; Haack, J; Hadig, T; Haidt, Dieter; Hajduk, L; Hampel, M; Haynes, W J; Heinzelmann, G; Henderson, R C W; Henschel, H; Herynek, I; Hess, M F; Hewitt, K; Hildesheim, W; Hiller, K H; Hilton, C D; Hladky, J; Hoeger, K C; Hoffmann, D; Holtom, T; Hoppner, M; Horisberger, R P; Hudgson, V L; Hufnagel, H; Hütte, M; Ibbotson, M; Itterbeck, H; Jacholkowska, A; Jacobsson, C; Jaffré, M; Janoth, J; Jansen, T; Johnson, D P; Jung, H; Jönsson, L B; Kalmus, Peter I P; Kander, M; Kant, D; Kaschowitz, R; Kathage, U; Katzy, J M; Kaufmann, H H; Kaufmann, O; Kazarian, S; Kenyon, Ian Richard; Kermiche, S; Keuker, C; Kiesling, C; Klein, M; Kleinwort, C; Knies, G; Kolanski, H; Kole, F; Kolya, S D; Korbel, V; Korn, M; Kostka, P; Kotelnikov, S K; Krasny, M W; Krehbiel, H; Krämerkämper, T; Krücker, D; Kuhlen, M; Kurca, T; Kurzhofer, J; Köhler, T; Köhne, J H; Küster, H; Lacour, D; Laforge, B; Lander, R; Landon, M P J; Lange, W; Langenegger, U; Laporte, J F; Lebedev, A; Lehner, F; Levonian, S; Lindström, G; Lindstrøm, M; Link, J; Linsel, F; Lipinski, J; List, B; Lobo, G; Loch, P; Lomas, J W; Lubimov, V; Lüke, D; López, G C; Magnussen, N; Malinovskii, E I; Mani, S; Maracek, R; Marage, P; Marks, J; Marshall, R; Martens, J; Martin, G; Martin, R D; Martyn, H U; Martyniak, J; Mavroidis, A; Maxfield, S J; McMahon, S J; Mehta, A; Meier, K; Meyer, A; Meyer, H; Meyer, J; Meyer, P O; Migliori, A; Mikocki, S; Milstead, D; Moeck, J; Moreau, F; Morris, J V; Mroczko, E; Murín, P; Müller, G; Müller, K; Nagovitsin, V; Nahnhauer, R; Naroska, Beate; Naumann, T; Negri, I; Newman, P R; Newton, D; Neyret, D; Nguyen, H K; Nicholls, T C; Niebergall, F; Niebuhr, C B; Niedzballa, C; Niggli, H; Nisius, R; Nowak, G; Noyes, G W; Nyberg-Werther, M; Oakden, M N; Oberlack, H; Olsson, J E; Ozerov, D; Palmen, P; Panaro, E; Panitch, A; Pascaud, C; Patel, G D; Pawletta, H; Peppel, E; Phillips, J P; Pieuchot, A; Pitzl, D; Pope, G; Prell, S; Pérez, E; Rabbertz, K; Reimer, P; Reinshagen, S; Rick, Hartmut; Riech, V; Riedlberger, J; Riepenhausen, F; Riess, S; Rizvi, E; Robertson, S M; Robmann, P; Roloff, H E; Roosen, R; Rosenbauer, K; Rostovtsev, A A; Rouse, F; Royon, C; Rusakov, S V; Rybicki, K; Rädel, G; Rüter, K; Sankey, D P C; Schacht, P; Schiek, S; Schleif, S; Schleper, P; Schmidt, D; Schmidt, G; Schröder, V; Schuhmann, E; Schwab, B; Schöning, A; Sefkow, F; Seidel, M; Sell, R; Semenov, A A; Shekelian, V I; Shevyakov, I; Shtarkov, L N; Siegmon, G; Siewert, U; Sirois, Y; Skillicorn, Ian O; Smirnov, P; Smith, J R; Solochenko, V; Soloviev, Yu V; Specka, A E; Spiekermann, J; Spielman, S; Spitzer, H; Squinabol, F; Starosta, R; Steenbock, M; Steffen, P; Steinberg, R; Steiner, H; Steinhart, J; Stella, B; Stellberger, A; Stier, J; Stiewe, J; Stolze, K; Straumann, U; Struczinski, W; Stösslein, U; Sutton, J P; Tapprogge, Stefan; Tasevsky, M; Theissen, J; Thiebaux, C; Thompson, G; Truöl, P; Tsipolitis, G; Turnau, J; Tutas, J; Uelkes, P; Usik, A; Valkár, S; Valkárová, A; Vallée, C; Van Esch, P; Van Mechelen, P; Van den Plas, D; Vazdik, Ya A; Verrecchia, P; Villet, G; Wacker, K; Wagener, A; Wagener, M; Walther, A; Waugh, B; Weber, G; Weber, M; Wegener, D; Wegner, A; Wengler, T; Werner, M; West, L R; Wiesand, S; Wilksen, T; Willard, S; Winde, M; Winter, G G; Wittek, C; Wobisch, M; Wünsch, E; Zarbock, D; Zhang, Z; Zhokin, A S; Zini, P; Zomer, F; Zsembery, J; Zuber, K; Zur Nedden, M; Zácek, J; de Roeck, A; von Schlippe, W
1996-01-01
Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastic ep scattering have been measured over a large kinematical region. The evolution with $W$ and $Q^2$ of the multiplicity distribution and of the multiplicity moments in pseudorapidity domains of varying size is studied in the current fragmentation region of the hadronic centre-of-mass frame. The results are compared with data from fixed target lepton-nucleon interactions, $e^+e^-$ annihilations and hadron-hadron collisions as well as with expectations from QCD based parton models. Fits to the Negative Binomial and Lognormal distributions are presented.
Parola, Alberto; Piazza, Roberto; Degiorgio, Vittorio
2014-09-01
We provide a general microscopic theory of the scattering cross-section and of the refractive index for a system of interacting colloidal particles, exact at second order in the molecular polarizabilities. In particular: (a) we show that the structural features of the suspension are encoded into the forward scattered field by multiple scattering effects, whose contribution is essential for the so-called "optical theorem" to hold in the presence of interactions; (b) we investigate the role of radiation reaction on light extinction; (c) we discuss our results in the framework of effective medium theories, presenting a general result for the effective refractive index valid, whatever the structural properties of the suspension, in the limit of particles much larger than the wavelength; (d) by discussing strongly-interacting suspensions, we unravel subtle anomalous dispersion effects for the suspension refractive index.
Medium effect in high density region probed by nucleus-nucleus elastic scattering
Furumoto, T; Yamamoto, Y
2014-01-01
We investigate the sensitivity of the medium effect in the high density region on the nucleus-nucleus elastic scattering in the framework of the double-folding (DF) model with the complex $G$-matrix interaction. First, the evaluating position of the local density, which is an ambiguity of the DF model, is investigated. However, the effect has a minor role to the nucleus-nucleus system. Next, the medium effect including three-body-force (TBF) effect is investigated with two methods. In the both methods, the medium effect is clearly seen on the potential and the elastic cross section, but not on the total reaction cross section. Finally, we make clear the crucial role of the TBF effect up to $k_F =$ 1.6 fm$^{-1}$ in the nucleus-nucleus elastic scattering.
Selective coupling of optical energy into the fundamental diffusion mode of a scattering medium
Ojambati, Oluwafemi S; Lagendijk, Ad; Mosk, Allard P; Vos, Willem L
2015-01-01
We demonstrate experimentally that optical wavefront shaping selectively couples light into the fundamental diffusion mode of a scattering medium. The total energy density inside a scattering medium of zinc oxide (ZnO) nanoparticles was probed by measuring the emitted fluorescent power of spheres that were randomly positioned inside the medium. The fluorescent power of an optimized incident wave front is observed to be enhanced compared to a non-optimized incident front. The observed enhancement increases with sample thickness. Based on diffusion theory, we derive a model wherein the distribution of energy density of wavefront-shaped light is described by the fundamental diffusion mode. The agreement between our model and the data is striking not in the least since there are no adjustable parameters. Enhanced total energy density is crucial to increase the efficiency of white LEDs, solar cells, and of random lasers, as well as to realize controlled illumination in biomedical optics.
Diffusion and multiple anisotropic scattering for global illumination in clouds
Energy Technology Data Exchange (ETDEWEB)
Max, N L; Schussman, G; Miyazaki, R; Iwasaki, K; Nishita, T
2003-10-14
The diffusion method is a good approximation inside the dense core of a cloud, but not at the more tenuous boundary regions. Also, it breaks down in regions where the density of scattering droplets is zero. We have enhanced it by using hardware cell projection volume rendering at cloud border voxels to account for the straight line light transport across these empty regions. We have also used this hardware volume rendering at key voxels in the low-density boundary regions to account for the multiple anisotropic scattering of the environment.
Correction to the Moliere's formula for multiple scattering
Lee, R N
2008-01-01
The quasiclassical correction to the Moliere's formula for multiple scattering is derived. The consideration is based on the scattering amplitude, obtained with the first quasiclassical correction taken into account for arbitrary localized but not spherically symmetric potential. Unlike the leading term, the correction to the Moliere's formula contains the target density $n$ and thickness $L$ not only in the combination $nL$ (areal density). Therefore, this correction can be reffered to as the bulk density correction. It turns out that the bulk density correction is small even for high density. This result explains the wide region of applicability of the Moliere's formula.
Moufekkir, F.; Moussaoui, M. A.; Mezrhab, A.; Naji, H.; Lemonnier, D.
2012-09-01
This paper deals with the numerical solution for natural convection and volumetric radiation in an isotropic scattering medium within a heated square cavity using a hybrid thermal lattice Boltzmann method (HTLBM). The multiple relaxation time lattice Boltzmann method (MRT-LBM) has been coupled to the finite difference method (FDM) to solve momentum and energy equations, while the discrete ordinates method (DOM) has been adopted to solve the radiative transfer equation (RTE) using the S8 quadrature. Based on these approaches, the effects of various influencing parameters such as the Rayleigh number (Ra), the wall emissivity (ει), the Planck number (Pl), and the scattering albedo (ω), have been considered. The results presented in terms of isotherms, streamlines and averaged Nusselt number, show that in absence of radiation, the temperature and the flow fields are centro-symmetrics and the cavity core is thermally stratified. However, radiation causes an overall increase in the temperature and velocity gradients along both thermally active walls. The maximum heat transfer rate is obtained when the surfaces of the enclosure walls are regarded as blackbodies. It is also seen that the scattering medium can generate a multicellular flow.
Mannoni, A; Flesia, C; Bruscaglioni, P; Ismaelli, A
1996-12-20
Lidar measurements are often interpreted on the basis of two fundamental assumptions: absence of multiple scattering and sphericity of the particles that make up the diffusing medium. There are situations in which neither holds true. We focus our interest on multiply-scattered returns from homogeneous layers of monodisperse, randomly oriented, axisymmetric nonspherical particles. T(2) Chebyshev particles have been chosen and their single-scattering properties have been reviewed. A Monte Carlo procedure has been employed to calculate the backscattered signal for several fields of view. Comparisons with the case of scattering from equivalent (equal-volume) spheres have been carried out (narrow polydispersions have been used to smooth the phase functions' oscillations). Our numerical effort highlights a considerable variability in the intensity of the multiply-scattered signal, which is a consequence of the strong dependence of the backscattering cross section on deformation of the particles. Even more striking effects have been noted for depolarization; peculiar behavior was observed at moderate optical depths when particles characterized by a large backscattering depolarization ratio were employed in our simulations. The sensitivity of depolarization to even small departures from sphericity, in spite of random orientation of the particles, has been confirmed. The results obtained with the Monte Carlo codes have been successfully checked with an analytical formula for double scattering.
Multiple scattering and N-body approaches to nuclear reactions
Energy Technology Data Exchange (ETDEWEB)
Picklesimer, A.; Tandy, P.C.; Thaler, R.M.
1983-02-01
The relationship between conventional multiple scattering approaches and the recently developed N-body approaches to nuclear reactions is considered with a view towards elastic scattering applications. Connectivity expansions in the N-body approach and multiple scattering expansions in the Watson approach are developed by a common technique so that a comparison of the physical content of each can be made. In the N-body case this leads to a new derivation of the equations of Bencze, Redish, and Sloan in both particle-labelled and partition-labelled form and this yields new insight into minimal dimensionality of these equations and into the role of channel coupling schemes within this formulation. The relative simplicity and generality with which these results are obtained is designed to be easily understood by those unfamiliar with N-body formalisms. The two approaches are contrasted first for the three-particle problem and subsequently for the many-body problem. We argue that a strict adherence to the connected-kernel property which is advantageous for the three-particle problem may not be so advantageous for the many-body elastic scattering problem. Undesirable physical characteristics of the connectivity expansion for elastic scattering are identified and their rectification is discussed. The off-shell transformation associated with the N-body approach is examined critically. The origin of the multiplicity of N-body coupling schemes is elucidated. It is shown that a modified concept of connectivity, called inclusive connectivity, can be introduced to guide expansions which can be truncated in a physically meaningful way. The inclusive connectivity expansion is seen to be identical to the spectator expansion for an elementary projectile but differs in the case of a composite projectile.
Mounaix, Mickael; Gigan, Sylvain
2016-01-01
We report a method to characterize the propagation of an ultrashort pulse of light through a multiple scattering medium by measuring its time-resolved transmission matrix. This method is based on the use of a spatial light modulator together with a coherent time-gated detection of the transmitted speckle field. Using this matrix, we demonstrate the focusing of the scattered pulse at any arbitrary position in space and time after the medium. Our approach opens new perspectives for both fundamental studies and applications in imaging and coherent control in disordered media.
Energy Technology Data Exchange (ETDEWEB)
Nishimura, Tomoaki, E-mail: t-nishi@hosei.ac.jp
2016-03-15
A computer simulation program for ion scattering and its graphical user interface (MEISwin) has been developed. Using this program, researchers have analyzed medium-energy ion scattering and Rutherford backscattering spectrometry at Ritsumeikan University since 1998, and at Rutgers University since 2007. The main features of the program are as follows: (1) stopping power can be chosen from five datasets spanning several decades (from 1977 to 2011), (2) straggling can be chosen from two datasets, (3) spectral shape can be selected as Gaussian or exponentially modified Gaussian, (4) scattering cross sections can be selected as Coulomb or screened, (5) simulations adopt the resonant elastic scattering cross section of {sup 16}O({sup 4}He, {sup 4}He){sup 16}O, (6) pileup simulation for RBS spectra is supported, (7) natural and specific isotope abundances are supported, and (8) the charge fraction can be chosen from three patterns (fixed, energy-dependent, and ion fraction with charge-exchange parameters for medium-energy ion scattering). This study demonstrates and discusses the simulations and their results.
Nishimura, Tomoaki
2016-03-01
A computer simulation program for ion scattering and its graphical user interface (MEISwin) has been developed. Using this program, researchers have analyzed medium-energy ion scattering and Rutherford backscattering spectrometry at Ritsumeikan University since 1998, and at Rutgers University since 2007. The main features of the program are as follows: (1) stopping power can be chosen from five datasets spanning several decades (from 1977 to 2011), (2) straggling can be chosen from two datasets, (3) spectral shape can be selected as Gaussian or exponentially modified Gaussian, (4) scattering cross sections can be selected as Coulomb or screened, (5) simulations adopt the resonant elastic scattering cross section of 16O(4He, 4He)16O, (6) pileup simulation for RBS spectra is supported, (7) natural and specific isotope abundances are supported, and (8) the charge fraction can be chosen from three patterns (fixed, energy-dependent, and ion fraction with charge-exchange parameters for medium-energy ion scattering). This study demonstrates and discusses the simulations and their results.
A New Three-Dimensional Track Fit with Multiple Scattering
Berger, Niklaus; Kozlinskiy, Alexandr; Schöning, Andre
2016-01-01
Modern semiconductor detectors allow for charged particle tracking with ever increasing position resolution. Due to the reduction of the spatial hit uncertainties, multiple Coulomb scattering in the detector layers becomes the dominant source for tracking uncertainties. In this case long range correlations can be ignored, and the track fit can consequently be formulated as a sum of independent fits to hit triplets. In this paper we present an analytical solution for a three-dimensional triplet(s) fit in a homogeneous magnetic field based on a multiple scattering model. Track fitting of hit triplets is performed using a linearization ansatz. The momentum resolution is discussed for a typical spectrometer setup. Furthermore the track fit is compared with other track fits for two different pixel detector geometries, namely the Mu3e experiment at PSI and a typical high-energy collider experiment. For a large momentum range the triplets fit provides a significant better performance than a single helix fit. The tri...
Electronic states of doped semiconductors: A multiple scattering approach
Ghazali, A.; Serre, J.
1983-03-01
The electronic structure of doped (and compensated) semiconductors is studied by using the Klauder's best multiple-scattering approximation. Electron correlations are also included. It is shown that as the impurity concentration is decreased, the band tail gradually splits off from the main band giving an impurity band. The domains of existence of extended states and localized states have been recognized by analyzing the shape of spectral densities. Lastly, our results are confronted with various experiments.
Institute of Scientific and Technical Information of China (English)
无
1998-01-01
The discrete-ordinates method is a simple,accurate and of little computational time solution to predict the radiactive heat transfer in the combustion chambers,In this paper,three-dimension radiative problems for absorbing-emitting-scattering medium are modeled using this method in the rectangular enclosure.And in addition,new discrete-ordinates are developed to study the absorbing-emitting-scattering radiation processes for complex phase function.The reasonable results can be obtained though these new ordinates,yet the deviated results are only obtained through conventional Sn ordinates.
Scatter broadening of pulsars and implications on the interstellar medium turbulence
Xu, Siyao
2016-01-01
Observations reveal a uniform Kolmogorov turbulence throughout the diffuse ionized interstellar medium (ISM) and supersonic turbulence preferentially located in the Galactic plane. Correspondingly, we consider the Galactic distribution of electron density fluctuations consisting of not only a Kolmogorov density spectrum but also a short-wave-dominated density spectrum with the density structure formed at small scales due to shocks. The resulting dependence of the scatter broadening time on the dispersion measure (DM) naturally interprets the existing observational data for both low and high-DM pulsars. According to the criteria that we derive for a quantitative determination of scattering regimes over wide ranges of DMs and frequencies $\
Multiple-scattering theory. New developments and applications
Energy Technology Data Exchange (ETDEWEB)
Ernst, Arthur
2007-12-04
Multiple-scattering theory (MST) is a very efficient technique for calculating the electronic properties of an assembly of atoms. It provides explicitly the Green function, which can be used in many applications such as magnetism, transport and spectroscopy. This work gives an overview on recent developments of multiple-scattering theory. One of the important innovations is the multiple scattering implementation of the self-interaction correction approach, which enables realistic electronic structure calculations of systems with localized electrons. Combined with the coherent potential approximation (CPA), this method can be applied for studying the electronic structure of alloys and as well as pseudo-alloys representing charge and spin disorder. This formalism is extended to finite temperatures which allows to investigate phase transitions and thermal fluctuations in correlated materials. Another novel development is the implementation of the self-consistent non-local CPA approach, which takes into account charge correlations around the CPA average and chemical short range order. This formalism is generalized to the relativistic treatment of magnetically ordered systems. Furthermore, several improvements are implemented to optimize the computational performance and to increase the accuracy of the KKR Green function method. The versatility of the approach is illustrated in numerous applications. (orig.)
Few-Photon Scattering in Dispersive Waveguides with Multiple Qubits
Kocabaş, Şükrü Ekin
2016-01-01
We extend the Krylov subspace based time dependent numerical simulation technique for a qubit interacting with photons in a waveguide to the multiple qubit case. We analyze photon scattering from two qubits analytically and derive expressions for the bound states in the continuum (BIC). We show how the BIC can be excited. We use the BIC in a recent Pauli Z gate proposal involving decoherence free subspaces and obtain the gate fidelity as a function of the gate parameters. The techniques presented in the paper are useful for investigating the time evolution of quantum gates and other many-body systems with multiple quenches in the Hamiltonian.
Application of multiple scattering theory to lower-energy elastic nucleon-nucleus scattering
Energy Technology Data Exchange (ETDEWEB)
Chinn, C.R.; Elster, C.; Thaler, R.M.; Weppner, S.P. (Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States) Center for Computationally Intensive Physics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States) Institute of Nuclear Particle Physics, and Department of Physics, Ohio University, Athens, Ohio 45701 (United States) Physics Department, Case Western Reserve University, Cleveland, Ohio 44106 (United States))
1995-03-01
The optical model potentials for nucleon-nucleus elastic scattering at 65 meV are calculated for [sup 12]C, [sup 16]O, [sup 28]Si, [sup 40]Ca, [sup 56]Fe, [sup 90]Zr, and [sup 208]Pb in first-order multiple scattering theory, following the prescription of the spectator expansion, where the only inputs are the free nucleon-nucleon (NN) potentials, the nuclear densities, and the nuclear mean field as derived from microscopic nuclear structure calculations. These potentials are used to predict differential cross sections, analyzing powers, and spin rotation functions for neutron and proton scattering at 65 MeV projectile energy and compared with available experimental data. The theoretical curves are in very good agreement with the data. The modification of the propagator due to the coupling of the struck nucleon to the residual nucleus is seen to be significant at this energy and invariably improves the congruence of theoretical prediction and measurement.
Application of multiple scattering theory to lower-energy elastic nucleon-nucleus scattering
Chinn, C. R.; Elster, Ch.; Thaler, R. M.; Weppner, S. P.
1995-03-01
The optical model potentials for nucleon-nucleus elastic scattering at 65 meV are calculated for 12C, 16O, 28Si, 40Ca, 56Fe, 90Zr, and 208Pb in first-order multiple scattering theory, following the prescription of the spectator expansion, where the only inputs are the free nucleon-nucleon (NN) potentials, the nuclear densities, and the nuclear mean field as derived from microscopic nuclear structure calculations. These potentials are used to predict differential cross sections, analyzing powers, and spin rotation functions for neutron and proton scattering at 65 MeV projectile energy and compared with available experimental data. The theoretical curves are in very good agreement with the data. The modification of the propagator due to the coupling of the struck nucleon to the residual nucleus is seen to be significant at this energy and invariably improves the congruence of theoretical prediction and measurement.
An approximate factorization method for inverse medium scattering with unknown buried objects
Qu, Fenglong; Yang, Jiaqing; Zhang, Bo
2017-03-01
This paper is concerned with the inverse problem of scattering of time-harmonic acoustic waves by an inhomogeneous medium with different kinds of unknown buried objects inside. By constructing a sequence of operators which are small perturbations of the far-field operator in a suitable way, we prove that each operator in this sequence has a factorization satisfying the Range Identity. We then develop an approximate factorization method for recovering the support of the inhomogeneous medium from the far-field data. Finally, numerical examples are provided to illustrate the practicability of the inversion algorithm.
Scatter Broadening of Pulsars and Implications on the Interstellar Medium Turbulence
Xu, Siyao; Zhang, Bing
2017-01-01
Observations reveal a uniform Kolmogorov turbulence throughout the diffuse ionized interstellar medium (ISM) and supersonic turbulence preferentially located in the Galactic plane. Correspondingly, we consider the Galactic distribution of electron density fluctuations consisting of not only a Kolmogorov density spectrum but also a short-wave-dominated density spectrum with the density structure formed at small scales due to shocks. The resulting dependence of the scatter broadening time on the dispersion measure (DM) naturally interprets the existing observational data for both low- and high-DM pulsars. According to the criteria that we derive for a quantitative determination of scattering regimes over wide ranges of DMs and frequencies ν, we find that the pulsars with low DMs are primarily scattered by the Kolmogorov turbulence, while those at low Galactic latitudes with high DMs undergo more enhanced scattering dominated by the supersonic turbulence, where the corresponding density spectrum has a spectral index of ≈ 2.6. Furthermore, by considering a volume filling factor of the density structures with the dependence on ν as \\propto {ν }1.4 in the supersonic turbulence, our model can also explain the observed shallower ν scaling of the scattering time than the Kolmogorov scaling for the pulsars with relatively large DMs. The comparison between our analytical results and the scattering measurements of pulsars in turn makes a useful probe of the properties of the large-scale ISM turbulence, e.g., an injection scale of ∼100 pc, and also characteristics of small-scale density structures.
Perfectly-matched-layer boundary integral equation method for wave scattering in a layered medium
Lu, Wangtao; Qian, Jianliang
2016-01-01
For scattering problems of time-harmonic waves, the boundary integral equation (BIE) methods are highly competitive, since they are formulated on lower-dimension boundaries or interfaces, and can automatically satisfy outgoing radiation conditions. For scattering problems in a layered medium, standard BIE methods based on the Green's function of the background medium must evaluate the expensive Sommefeld integrals. Alternative BIE methods based on the free-space Green's function give rise to integral equations on unbounded interfaces which are not easy to truncate, since the wave fields on these interfaces decay very slowly. We develop a BIE method based on the perfectly matched layer (PML) technique. The PMLs are widely used to suppress outgoing waves in numerical methods that directly discretize the physical space. Our PML-based BIE method uses the Green's function of the PML-transformed free space to define the boundary integral operators. The method is efficient, since the Green's function of the PML-tran...
Time-domain Helmholtz-Kirchhoff integral for surface scattering in a refractive medium.
Choo, Youngmin; Song, H C; Seong, Woojae
2017-03-01
The time-domain Helmholtz-Kirchhoff (H-K) integral for surface scattering is derived for a refractive medium, which can handle shadowing effects. The starting point is the H-K integral in the frequency domain. In the high-frequency limit, the Green's function can be calculated by ray theory, while the normal derivative of the incident pressure from a point source is formulated using the ray geometry and ray-based Green's function. For a corrugated pressure-release surface, a stationary phase approximation can be applied to the H-K integral, reducing the surface integral to a line integral. Finally, a computationally-efficient, time-domain H-K integral is derived using an inverse Fourier transform. A broadband signal scattered from a sinusoidal surface in an upwardly refracting medium is evaluated with and without geometric shadow corrections, and compared to the result from a conventional ray model.
Scattering by a perfect electromagnetic conductor (PEMC) plate embedded in lossy medium
Ahmed, Saeed; Khalid Khan, Muhammad; Rehman, Atta Ur
2016-07-01
In this article, we develop an analytic theory for a perfect electromagnetic conductor (PEMC) plate embedded in lossy medium. The duality transformation introduced by Lindell and Sihvola is applied to study the electromagnetic wave scattering by a PEMC plate. Perfect electric conductor and perfect magnetic conductor are the limiting cases of PEMC media. Here, we study monoscattering by PEMC plate embedded in four different soil models. Numerical results are discussed and compared with the available literature.
Multiple Scattering Model for Optical Coherence Tomography with Rytov Approximation
Li, Muxingzi
2017-04-24
Optical Coherence Tomography (OCT) is a coherence-gated, micrometer-resolution imaging technique that focuses a broadband near-infrared laser beam to penetrate into optical scattering media, e.g. biological tissues. The OCT resolution is split into two parts, with the axial resolution defined by half the coherence length, and the depth-dependent lateral resolution determined by the beam geometry, which is well described by a Gaussian beam model. The depth dependence of lateral resolution directly results in the defocusing effect outside the confocal region and restricts current OCT probes to small numerical aperture (NA) at the expense of lateral resolution near the focus. Another limitation on OCT development is the presence of a mixture of speckles due to multiple scatterers within the coherence length, and other random noise. Motivated by the above two challenges, a multiple scattering model based on Rytov approximation and Gaussian beam optics is proposed for the OCT setup. Some previous papers have adopted the first Born approximation with the assumption of small perturbation of the incident field in inhomogeneous media. The Rytov method of the same order with smooth phase perturbation assumption benefits from a wider spatial range of validity. A deconvolution method for solving the inverse problem associated with the first Rytov approximation is developed, significantly reducing the defocusing effect through depth and therefore extending the feasible range of NA.
On-surface radiation condition for multiple scattering of waves
Acosta, Sebastian
2013-01-01
The formulation of the on-surface radiation condition (OSRC) is extended to handle wave scattering problems in the presence of multiple obstacles. The new multiple-OSRC simultaneously accounts for the outgoing behavior of the wave fields, as well as, the multiple wave reflections between the obstacles. Like boundary integral equations (BIE), this method leads to a reduction in dimensionality (from volume to surface) of the discretization region. However, as opposed to BIE, the proposed technique leads to boundary integrals with smooth kernels. In addition, under appropriate conditions, this approach leads to approximate explicit (up to numerical integration) formulas for the solution, avoiding the need to invert any operator or matrix. As a result, the computational effort is significantly reduced. This approach may serve as a fast method to explore parameter-spaces or as an inexpensive pre-conditioner for Krylov iterative solutions of BIE.
Ojambati, Oluwafemi S.; Yılmaz, Hasan; Lagendijk, Ad; Mosk, Allard P.; Vos, Willem L.
2016-03-01
Diffusion equation describes the energy density inside a scattering medium such as biological tissues and paint [1]. The solution of the diffusion equation is a sum over a complete set of eigensolutions that shows a characteristic linear decrease with depth in the medium. It is of particular interest if one could launch energy in the fundamental eigensolution, as this opens the opportunity to achieve a much greater internal energy density. For applications in optics, an enhanced energy density is vital for solid-state lighting, light harvesting in solar cells, low-threshold random lasers, and biomedical optics. Here we demonstrate the first ever selective coupling of optical energy into a diffusion eigensolution of a scattering medium of zinc oxide (ZnO) paint. To this end, we exploit wavefront shaping to selectively couple energy into the fundamental diffusion mode, employing fluorescence of nanoparticles randomly positioned inside the medium as a probe of the energy density. We observe an enhanced fluorescence in case of optimized incident wavefronts, and the enhancement increases with sample thickness, a typical mesoscopic control parameter. We interpret successfully our result by invoking the fundamental eigensolution of the diffusion equation, and we obtain excellent agreement with our observations, even in absence of adjustable parameters [2]. References [1] R. Pierrat, P. Ambichl, S. Gigan, A. Haber, R. Carminati, and R. Rotter, Proc. Natl. Acad. Sci. U.S.A. 111, 17765 (2014). [2] O. S. Ojambati, H. Yilmaz, A. Lagendijk, A. P. Mosk, and W. L. Vos, arXiv:1505.08103.
Location of the effective diffusing-photon source in a strongly scattering medium.
Kostko, A F; Pavlov, V A
1997-10-20
When a narrow laser beam illuminates a strongly scattering medium, the effective pointlike source of diffusing photons appears inside the medium. By the method worked out, which is based on measurements of the diffusive intensity of light emerging from a turbid spherical sample, the depth of this source site (the penetration depth) is determined relatively to the sample diameter, which is known accurately. By using this method of locating the effective source, we have discovered that its position inside the medium is unexpectedly deep. We obtained the penetration depth D(0) = 4.6 l* +/- 0.7 l* instead of one transport mean free path, where l* is the value of D(0) in the standard diffusion theory. Information about this source dipping is useful in diffusing-photon correlation spectroscopy because of its influence on the geometric factor calculated from the diffusion equation.
Comparison of Geant4 multiple Coulomb scattering models with theory for radiotherapy protons
Makarova, Anastasia; Sauerwein, Wolfgang
2016-01-01
Usually, Monte Carlo models are validated against experimental data. However, models of multiple Coulomb scattering (MCS) in the Gaussian approximation are exceptional in that we have theories which are probably more accurate than the experiments which have, so far, been done to test them. In problems directly sensitive to the distribution of angles leaving the target, the relevant theory is the Moliere/Fano/Hanson variant of Moliere theory. For transverse spreading of the beam in the target itself, the theory of Preston and Koehler holds. Therefore, in this paper we compare Geant4 simulations, using the Urban and Wentzel models of MCS, with theory rather than experiment, revealing trends which would otherwise be obscured by experimental scatter. For medium-energy (radiotherapy) protons, and low-Z (water-like) target materials, Wentzel appears to be better than Urban in simulating the distribution of outgoing angles. For beam spreading in the target itself, the two models are essentially equal.
Multiple scattering of elastic waves: a numerical method for computing the effective wavenumbers
Chekroun, Mathieu; Lombard, Bruno; Piraux, Joël
2012-01-01
Elastic wave propagation is studied in a heterogeneous 2-D medium consisting of an elastic matrix containing randomly distributed circular elastic inclusions. The aim of this study is to determine the effective wavenumbers when the incident wavelength is similar to the radius of the inclusions. A purely numerical methodology is presented, with which the limitations usually associated with low scatterer concentrations can be avoided. The elastodynamic equations are integrated by a fourth-order time-domain numerical scheme. An immersed interface method is used to accurately discretize the interfaces on a Cartesian grid. The effective field is extracted from the simulated data, and signal-processing tools are used to obtain the complex effective wavenumbers. The numerical reference solution thus-obtained can be used to check the validity of multiple scattering analytical models. The method is applied to the case of concrete. A parametric study is performed on longitudinal and transverse incident plane waves at v...
Light organization of small particles by multiple scattering
Hang, Zhi Hong
Optical manipulation is of broad interest in physics, chemistry, and biology. In the literature, most of the studies are focused on the optical trapping on a single object. In this thesis, we investigated the light-induced interaction of a collection of particles. The light-induced interaction between small particles was studied by a hierarchy of methods including the dipole theory, the multiple scattering and Maxwell stress tensor formalism, and the finite-difference-time-domain method. We showed that the multiple scattering between small particles could induce a binding mechanism to stabilize optically organized structures, but at the same time induced an intrinsic unbinding mechanism. The stability of optically organized structure was studied and a concept of "optical density" was introduced to gauge the destabilizing effect. We found that light-induced forces could bind dielectric spheres into extended structures through two mechanisms, each with its own length scale which could be adjusted by the configuration of the external light source. By manipulating the commensurability of the two length scales, these two mechanisms cooperated to bind a large number of spheres. When the two length scales became incommensurate for some particular incident angle, the competition between the two mechanisms led to modulated structures and other complex phenomena such as re-entrant stability. We searched for the possibility for stabilizing larger clusters. For this purpose, we found that circularly polarized light bound dielectric spheres into large-scale two-dimensional hexagonal lattice and multiple scattering also induced a rotation of optically bound structures. We searched for configurations that could induce optical trapping by field enhancement. Enhanced transmission on perforated metallic film system was studied. Surface modes bound on multi perforated perfect metal plate system were analytical solved and related to different high transmittance modes. Near
Haïat, G; Naili, S
2011-02-01
Speed of sound measurements are used clinically to assess bone strength. Trabecular bone is an attenuating composite material in which negative values of velocity dispersion have been measured; this behavior remaining poorly explained physically. The aim of this work is to describe the ultrasonic propagation in trabecular bone modeled by infinite cylinders immersed in a saturating matrix and to derive the physical determinants of velocity dispersion. An original homogenization model accounting for the coupling of independent scattering and absorption phenomena allows the computation of phase velocity and of dispersion while varying bone properties. The first step of the model consists in the computation of the attenuation coefficient at all frequencies. The second step of the model corresponds to the application of the general Kramers-Krönig relationship to derive the frequency dependence of phase velocity. The model predicts negative values of velocity dispersion in agreement with experimental results obtained in phantoms mimicking trabecular bone. In trabecular bone, only negative values of velocity dispersion are predicted by the model, which span within the range of values measured experimentally. However, the comparison of the present results with results obtained in Haiat et al. (J Acoust Soc Am 124:4047-4058, 2008) assuming multiple scattering indicates that accounting for multiple scattering phenomena leads to a better prediction of velocity dispersion in trabecular bone.
Influence of Multiple Scattering on Two-Pion Correlation Measurements
Institute of Scientific and Technical Information of China (English)
TANG Gui-Xin; ZHANG Wei-Ning; LIU Yi-Ming; HUO Lei; ZHANG Jing-Bo
2004-01-01
@@ Using the relativistic quantum molecular dynamics model, we study the influence of multiple scattering on the result of two-pion correlation measurements. The scales of pion spatial distribution are larger at thermal freezeout than at chemical freeze-out. By varying the value of the parameter of cross section from 0 to 90mb, we find that the sizes of pion source measured by two-particle correlation functions are almost independent of the parameter of cross section. However, λ parameters are sensitive to the parameter of cross section.
Multiple scattering of light in three-dimensional photonic quasicrystals.
Ledermann, Alexandra; Wiersma, Diederik S; Wegener, Martin; von Freymann, Georg
2009-02-01
Recent experiments on three-dimensional icosahedral dielectric photonic quasicrystals have shown several unexpected features: transmitted femtosecond pulses developed a trailing "diffusive" exponential tail and the sum of (zeroth-order) transmittance and reflectance was well below unity. These experimental findings have previously been ascribed to sample imperfections. Here, we analyze these findings by using 3D periodic approximants of the ideal photonic quasicrystals. We show that the experimental observations can be explained in terms of multiple scattering of light within these structures, i.e., in terms of intrinsic rather than purely extrinsic quasicrystal properties.
Proton radiography, nuclear cross sections and multiple Coulomb scattering
Energy Technology Data Exchange (ETDEWEB)
Sjue, Sky K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-11-04
The principles behind proton radiography including multiple Coulomb scattering are discussed for a purely imaginary square well nucleus in the eikonal approximation. It is found that a very crude model can reproduce the angular dependence of the cross sections measured at 24 GeV/c. The largest differences are ~3% for the 4.56 mrad data, and ~4% for the 6.68 mrad data. The prospect of understanding how to model deterministically high-energy proton radiography over a very large range of energies is promising, but it should be tested more thoroughly.
New electron multiple scattering distributions for Monte Carlo transport simulation
Energy Technology Data Exchange (ETDEWEB)
Chibani, Omar (Haut Commissariat a la Recherche (C.R.S.), 2 Boulevard Franz Fanon, Alger B.P. 1017, Alger-Gare (Algeria)); Patau, Jean Paul (Laboratoire de Biophysique et Biomathematiques, Faculte des Sciences Pharmaceutiques, Universite Paul Sabatier, 35 Chemin des Maraichers, 31062 Toulouse cedex (France))
1994-10-01
New forms of electron (positron) multiple scattering distributions are proposed. The first is intended for use in the conditions of validity of the Moliere theory. The second distribution takes place when the electron path is so short that only few elastic collisions occur. These distributions are adjustable formulas. The introduction of some parameters allows impositions of the correct value of the first moment. Only positive and analytic functions were used in constructing the present expressions. This makes sampling procedures easier. Systematic tests are presented and some Monte Carlo simulations, as benchmarks, are carried out. ((orig.))
Aethalometer multiple scattering correction Cref for mineral dust aerosols
Di Biagio, Claudia; Formenti, Paola; Cazaunau, Mathieu; Pangui, Edouard; Marchand, Nicolas; Doussin, Jean-François
2017-08-01
In this study we provide a first estimate of the Aethalometer multiple scattering correction Cref for mineral dust aerosols. Cref is an empirical constant used to correct the aerosol absorption coefficient measurements for the multiple scattering artefact of the Aethalometer; i.e. the filter fibres on which aerosols are deposited scatter light and this is miscounted as absorption. The Cref at 450 and 660 nm was obtained from the direct comparison of Aethalometer data (Magee Sci. AE31) with (i) the absorption coefficient calculated as the difference between the extinction and scattering coefficients measured by a Cavity Attenuated Phase Shift Extinction analyser (CAPS PMex) and a nephelometer respectively at 450 nm and (ii) the absorption coefficient from a MAAP (Multi-Angle Absorption Photometer) at 660 nm. Measurements were performed on seven dust aerosol samples generated in the laboratory by the mechanical shaking of natural parent soils issued from different source regions worldwide. The single scattering albedo (SSA) at 450 and 660 nm and the size distribution of the aerosols were also measured. Cref for mineral dust varies between 1.81 and 2.56 for a SSA of 0.85-0.96 at 450 nm and between 1.75 and 2.28 for a SSA of 0.98-0.99 at 660 nm. The calculated mean for dust is 2.09 (±0.22) at 450 nm and 1.92 (±0.17) at 660 nm. With this new Cref the dust absorption coefficient by the Aethalometer is about 2 % (450 nm) and 11 % (660 nm) higher than that obtained by using Cref = 2.14 at both 450 and 660 nm, as usually assumed in the literature. This difference induces a change of up to 3 % in the dust SSA at 660 nm. The Cref seems to be independent of the fine and coarse particle size fractions, and so the obtained Cref can be applied to dust both close to sources and following transport. Additional experiments performed with pure kaolinite minerals and polluted ambient aerosols indicate Cref of 2.49 (±0.02) and 2.32 (±0.01) at 450 and 660 nm (SSA = 0.96-0.97) for
Bürgel, Florian; Kazimierski, Kamil S.; Lechleiter, Armin
2017-06-01
We present a fast computational framework for the inverse medium problem in scattering, i.e. we look at discretization, reconstruction and numerical performance. The Helmholtz equation in two and three dimensions is used as a physical model of scattering including point sources and plane waves as incident fields as well as near and far field measurements. For the reconstruction of the medium, we set up a rapid variational regularization scheme and indicate favorable choices of the various parameters. The underlying paradigm is, roughly speaking, to minimize the discrepancy between the reconstruction and measured data while, at the same time, taking into account various structural a-priori information via suitable penalty terms. In particular, the involved penalty terms are designed to promote information expected in real-world environments. To this end, a combination of sparsity promoting terms, total variation, and physical bounds of the inhomogeneous medium, e.g. positivity constraints, is employed in the regularization penalty. A primal-dual algorithm is used to solve the minimization problem related to the variational regularization. The computational feasibility, performance and efficiency of the proposed approach is demonstrated for synthetic as well as experimentally measured data.
Multiply scattered waves through a spatially random medium : entropy production and depolarization
Bicout, Dominique; Brosseau, Christian
1992-11-01
This paper deals with the depolarization and decoherence effects of an incident pure state of polarization and of arbitrary state of coherence by a linear scattering medium which changes randomly with position. Using symmetry arguments and a maximum entropy principle we deduce the general form of the Mueller matrix describing the scattering medium which is consistent with the explicit computation done in the context of the Bethe-Salpeter equation handled in the diffusion approximation. The main result expresses the output degree of polarization and degree of spatial coherence as a function of the number of scattering events. From these results, two main conclusions can be drawn. The first is that the entropy production per scattering due to the irreversible process of depolarization is an exponentially decreasing function of the number of scattering events. The second result obtained is that full depolarization of linearly polarized light by Rayleigh scatterers requires more scattering events (typically a factor-of-2) than are required for a circularly polarized lightwave. Dans cette étude, on considère les phénomènes de dépolarisation et de décohérence d'un faisceau d'ondes planes incident, d'état pur de polarisation et d'état arbitraire de cohérence, par intéraction avec un milieu diffusant désordonné. Par des arguments de symétrie et un principe d'entropie maximum, nous déduisons la forme de la matrice de Mueller caractérisant le milieu diffusant qui est en accord avec le calcul explicite basé sur l'équation de Bethe-Salpeter traitée dans l'approximation de la diffusion. Le résultat principal exprime les degrés de polarisation et de cohérence spatiale en fonction du nombre de diffusions. Deux faits saillants sont à noter. Le premier exprime la décroissance exponentielle de la production d'entropie due à l'irréversibilité du processus de dépolarisation, en fonction du nombre de diffusions. Le second indique que la dépolarisation compl
Fining of Red Wine Monitored by Multiple Light Scattering.
Ferrentino, Giovanna; Ramezani, Mohsen; Morozova, Ksenia; Hafner, Daniela; Pedri, Ulrich; Pixner, Konrad; Scampicchio, Matteo
2017-07-12
This work describes a new approach based on multiple light scattering to study red wine clarification processes. The whole spectral signal (1933 backscattering points along the length of each sample vial) were fitted by a multivariate kinetic model that was built with a three-step mechanism, implying (1) adsorption of wine colloids to fining agents, (2) aggregation into larger particles, and (3) sedimentation. Each step is characterized by a reaction rate constant. According to the first reaction, the results showed that gelatin was the most efficient fining agent, concerning the main objective, which was the clarification of the wine, and consequently the increase in its limpidity. Such a trend was also discussed in relation to the results achieved by nephelometry, total phenols, ζ-potential, color, sensory, and electronic nose analyses. Also, higher concentrations of the fining agent (from 5 to 30 g/100 L) or higher temperatures (from 10 to 20 °C) sped up the process. Finally, the advantage of using the whole spectral signal vs classical univariate approaches was demonstrated by comparing the uncertainty associated with the rate constants of the proposed kinetic model. Overall, multiple light scattering technique showed a great potential for studying fining processes compared to classical univariate approaches.
A new three-dimensional track fit with multiple scattering
Berger, Niklaus; Kozlinskiy, Alexandr; Kiehn, Moritz; Schöning, André
2017-02-01
Modern semiconductor detectors allow for charged particle tracking with ever increasing position resolution. Due to the reduction of the spatial hit uncertainties, multiple Coulomb scattering in the detector layers becomes the dominant source for tracking uncertainties. In this case long distance effects can be ignored for the momentum measurement, and the track fit can consequently be formulated as a sum of independent fits to hit triplets. In this paper we present an analytical solution for a three-dimensional triplet(s) fit in a homogeneous magnetic field based on a multiple scattering model. Track fitting of hit triplets is performed using a linearization ansatz. The momentum resolution is discussed for a typical spectrometer setup. Furthermore the track fit is compared with other track fits for two different pixel detector geometries, namely the Mu3e experiment at PSI and a typical high-energy collider experiment. For a large momentum range the triplets fit provides a significantly better performance than a single helix fit. The triplets fit is fast and can easily be parallelized, which makes it ideal for the implementation on parallel computing architectures.
Muon energy estimate through multiple scattering with the MACRO detector
Ambrosio, M; Auriemma, G; Bakari, D; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Becherini, Y; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bloise, C; Bower, C; Brigida, M; Bussino, S; Cafagna, F; Calicchio, M; Campana, D; Candela, A; Carboni, M; Caruso, R; Cassese, F; Cecchini, S; Cei, F; Chiarella, V; Choudhary, B C; Coutu, S; Cozzi, M; De Cataldo, G; De Deo, M; Dekhissi, H; De Marzo, C; De Mitri, I; Derkaoui, J; De Vincenzi, M; Di Credico, A; Dincecco, M; Erriquez, O; Favuzzi, C; Forti, C; Fusco, P; Giacomelli, G; Giannini, G; Giglietto, N; Giorgini, M; Grassi, M; Gray, L; Grillo, A; Guarino, F; Gustavino, C; Habig, A; Hanson, K; Heinz, R; Iarocci, E; Katsavounidis, E; Katsavounidis, I; Kearns, E; Kim, H; Kyriazopoulou, S; Lamanna, E; Lane, C; Levin, D S; Lindozzi, M; Lipari, P; Longley, N P; Longo, M J; Loparco, F; Maaroufi, F; Mancarella, G; Mandrioli, G; Margiotta, A; Marini, A; Martello, D; Marzari-Chiesa, A; Mazziotta, M N; Michael, D G; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S; Musser, J; Nicolò, D; Nolty, R; Orth, C; Osteria, G; Palamara, O; Patera, V; Patrizii, L; Pazzi, R; Peck, C W; Perrone, L; Petrera, S; Pistilli, P; Popa, V; Rainó, A; Reynoldson, J; Ronga, F; Rrhioua, A; Satriano, C; Scapparone, E; Scholberg, K; Sciubba, A; Serra, P; Sioli, M; Sirri, G; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, L R; Surdo, A; Tarle, G; Tatananni, E; Togo, V; Vakili, M; Walter, C W; Webb, R
2002-01-01
Muon energy measurement represents an important issue for any experiment addressing neutrino-induced up-going muon studies. Since the neutrino oscillation probability depends on the neutrino energy, a measurement of the muon energy adds an important piece of information concerning the neutrino system. We show in this paper how the MACRO limited streamer tube system can be operated in drift mode by using the TDCs included in the QTPs, an electronics designed for magnetic monopole search. An improvement of the space resolution is obtained, through an analysis of the multiple scattering of muon tracks as they pass through our detector. This information can be used further to obtain an estimate of the energy of muons crossing the detector. Here we present the results of two dedicated tests, performed at CERN PS-T9 and SPS-X7 beam lines, to provide a full check of the electronics and to exploit the feasibility of such a multiple scattering analysis. We show that by using a neural network approach, we are able to r...
Light scattering in a medium with fluctuating gyrotropy: Application to spin-noise spectroscopy
Kozlov, G. G.; Ryzhov, I. I.; Zapasskii, V. S.
2017-04-01
The spin-noise signal in the Faraday-rotation-based detection technique can be considered equally correctly either as a manifestation of the spin-flip Raman effect or as a result of light scattering in the medium with fluctuating gyrotropy. In this paper, we present rigorous description of the signal formation process upon heterodyning of the field scattered due to fluctuating gyrotropy. Along with conventional single-beam experimental arrangement, we consider here a more complicated, but more informative, two-beam configuration that implies the use of an auxiliary light beam passing through the same scattering volume and delivering additional scattered light to the detector. We show that the signal in the spin-noise spectroscopy (SNS) arising due to heterodyning of the scattered field is formed only by the scattered field components the wave vectors of which coincide with those of the probe field. Therefore, in principle, the detected signal in SNS can be increased by increasing overlap of the two fields in the momentum space. We also show that, in the two-beam geometry of SNS, contribution of the auxiliary (tilted) beam to the detected signal is produced only by the region of overlap between the two beams in real space and can be expressed analytically as the Fourier transform of the spatial correlation function of the gyrotropy at the difference of their wave vectors. These features of the two-beam geometry can be used for tomographic measurements in spin systems (a more sophisticated version of three-dimensional tomography proposed earlier) and for studying spatial spin correlations by means of noise spectroscopy.
Cross sections for medium energy He ions scattered from Hf and Au atoms
Energy Technology Data Exchange (ETDEWEB)
Nishimura, Tomoaki, E-mail: t-nishi@hosei.ac.jp [Research Center of Ion Beam Technology and College of Engineering, Hosei University, Koganei, Tokyo 184-8584 (Japan); Mitsuhara, Kei; Visikovskiy, Anton; Kido, Yoshiaki [Department of Physics, Ritsumeikan University, Kusatsu, Shiga-ken 525-8577 (Japan)
2012-06-01
The elastic scattering cross sections for medium energy He ions incident on Ni, Hf and Au atoms were measured precisely using a toroidal electrostatic analyzer. We prepared the targets of Ni({approx}1 nm)/HfO{sub 2}(1.5 nm)/Si(0 0 1) and Ni({approx}1 nm)/Au({approx}0.5 nm)/Si(1 1 1) and performed in situ ion scattering measurement under ultrahigh vacuum condition. The absolute amounts of Ni, Hf and Au were determined by Rutherford backscattering using 1.5 MeV He ions at a scattering angle of 150 Degree-Sign . The scattering cross sections for Hf and Au were normalized by those for Ni to avoid the ambiguities of the number of incident particles, solid angle subtended by a detector, detection efficiency and the He{sup +} fractions for the emerging He ions from the surfaces. The results obtained are compared with the simple Lee-Hart formula and the calculated values using the Moliere and ZBL potentials and the potentials derived from the Hartree-Fock-Slater wave functions.
IBC/FEM Analysis of Electromagnetic Scatter of Cavities Coated with Layered Medium
Institute of Scientific and Technical Information of China (English)
HE Xiao-xiang; XU Jin-ping
2006-01-01
The Leontovich impedance boundary condition (IBC) is combined with the edge-based finite element method (FEM) in this paper to analyze the electromagnetic (EM) scattering of cavities coated with a multilayered dielectric.The IBC on the surface of the medium and the boundary integral equation on the aperture of the cavity are transformed into the third boundary condition,and then the functional of the boundary value problem is obtained.The surface impedance of the layered dielectric is calculated by the generalized reflection coefficient; hence,the multi-reflection of the EM wave in the dielectric is involved.As a result,the IBC is improved.Numerical results are presented,which demonstrate that the presented IBC/FEM approach is accurate and convenient for the analysis of EM scattering of open-ended cavities coated with the dielectric.
Controlling the intensity of light in large areas at the interfaces of a scattering medium
Ojambati, Oluwafemi S; Gorter, Klaas-Jan; Mosk, Allard P; Vos, Willem L
2016-01-01
The recent advent of wave-shaping methods has demonstrated the focusing of light through and inside even the most strongly scattering materials. Typically in wavefront shaping, light is focused in an area with the size of one speckle spot. It has been shown that the intensity is not only increased in the target speckle spot, but also in an area outside the optimized speckle spot. Consequently, the total transmission is enhanced, even though only the intensity in a single speckle spot is controlled. Here, we experimentally study how the intensity enhancement on both interfaces of a scattering medium depends on the optimization area on the transmission side. We observe that as the optimization radius increases, the enhancement of the total transmitted intensity increases. We find a concomitant decrease of the total reflected intensity, which implies an energy redistribution between transmission and reflection channels. In addition, we find a qualitative evidence of a long-range reflection-transmission correlati...
High precision, medium flux rate CZT spectroscopy for coherent scatter imaging
Greenberg, Joel A.; Hassan, Mehadi; Brady, David J.; Iniewski, Kris
2016-05-01
CZT detectors are primary candidates for many next-generation X-ray imaging systems. These detectors are typically operated in either a high precision, low flux spectroscopy mode or a low precision, high flux photon counting mode. We demonstrate a new detector configuration that enables operation in a high precision, medium flux spectroscopy mode, which opens the potential for a variety of new applications in medical imaging, non-destructive testing and baggage scanning. In particular, we describe the requirements of a coded aperture coherent scattering X-ray system that can perform fast imaging with accurate material discrimination.
Directory of Open Access Journals (Sweden)
Hong Qi
2015-01-01
Full Text Available A maximum a posteriori (MAP estimation based on Bayesian framework is applied to image reconstruction of two-dimensional highly scattering inhomogeneous medium. The finite difference method (FDM and conjugate gradient (CG algorithm serve as the forward and inverse solving models, respectively. The generalized Gaussian Markov random field model (GGMRF is treated as the regularization, and finally the influence of the measurement errors and initial distributions is investigated. Through the test cases, the MAP estimate algorithm is demonstrated to greatly improve the reconstruction results of the optical coefficients.
Image process in imaging through a scattering medium using fs electronic holography
Institute of Scientific and Technical Information of China (English)
侯比学; 陈国夫
1999-01-01
Aimed at imaging technology through scattering medium using fs electronic holography, a set of image process algorithm is put forward. This algorithm can be divided into three stages. First, every hologram is pre-processed, whose contrast is enhanced. Second, the first-order spatial spectrum is low-pass-filtered through a two-step process, so that high-frequency noise can be removed. Finally, many reconstructed images are ensemble-averaged. This stage can smooth random noise and is advantageous to restraining the speckle noise of image. The operation of this algorithm shows that all of processes in the three stages have obvious effects on improving image quality.
The in-medium isovector pi N amplitude from low energy pion scattering
Friedman, E; Breitschopf, J; Clement, H; Denz, H; Doroshkevich, E; Erhardt, A; Hofman, G J; Meier, R; Wagner, G J; Yaari, G
2004-01-01
Differential cross sections for elastic scattering of 21.5 MeV positive and negative pions by Si, Ca, Ni and Zr have been measured as part of a study of the pion-nucleus potential across threshold. The `anomalous' repulsion in the s-wave term was observed, as is the case with pionic atoms. The extra repulsion can be accounted for by a chiral-motivated model where the pion decay constant is modified in the medium. Unlike in pionic atoms, the anomaly cannot be removed by merely introducing an empirical on-shell energy dependence.
In-medium isovector piN amplitude from low-energy pion scattering.
Friedman, E; Bauer, M; Breitschopf, J; Clement, H; Denz, H; Doroshkevich, E; Erhardt, A; Hofman, G J; Meier, R; Wagner, G J; Yaari, G
2004-09-17
Differential cross sections for elastic scattering of 21.5 MeV positive and negative pions by Si, Ca, Ni, and Zr have been measured as part of a study of the pion-nucleus potential across the threshold. The "anomalous" repulsion in the s-wave term was observed, as is the case with pionic atoms. The extra repulsion can be accounted for by a chiral-motivated model where the pion decay constant is modified in the medium. Unlike in pionic atoms, the anomaly cannot be removed by merely introducing an empirical on-shell energy dependence.
The in-medium isovector pi N amplitude from low energy pion scattering
Friedman, E; Bauer, M.; Breitschopf, J.; H. Clement; Denz, H; Doroshkevich, E.; Erhardt, A.; Hofman, G. J.; Meier, R.; Wagner, G. J.; Yaari, G
2004-01-01
Differential cross sections for elastic scattering of 21.5 MeV positive and negative pions by Si, Ca, Ni and Zr have been measured as part of a study of the pion-nucleus potential across threshold. The `anomalous' repulsion in the s-wave term was observed, as is the case with pionic atoms. The extra repulsion can be accounted for by a chiral-motivated model where the pion decay constant is modified in the medium. Unlike in pionic atoms, the anomaly cannot be removed by merely introducing an e...
In-Medium Isovector πN Amplitude from Low-Energy Pion Scattering
Friedman, E.; Bauer, M.; Breitschopf, J.; Clement, H.; Denz, H.; Doroshkevich, E.; Erhardt, A.; Hofman, G. J.; Meier, R.; Wagner, G. J.; Yaari, G.
2004-09-01
Differential cross sections for elastic scattering of 21.5MeV positive and negative pions by Si, Ca, Ni, and Zr have been measured as part of a study of the pion-nucleus potential across the threshold. The “anomalous” repulsion in the s-wave term was observed, as is the case with pionic atoms. The extra repulsion can be accounted for by a chiral-motivated model where the pion decay constant is modified in the medium. Unlike in pionic atoms, the anomaly cannot be removed by merely introducing an empirical on-shell energy dependence.
Koay, J Y
2014-01-01
We investigate the feasibility of detecting and probing various components of the ionized intergalactic medium (IGM) and their turbulent properties at radio frequencies through observations of scatter broadening of compact sources. There is a strong case for conducting targeted observations to resolve scatter broadening (where the angular size scales as $\\sim \
Institute of Scientific and Technical Information of China (English)
ZHAO Jing-de; LIU Ni; ZHONG Ke
2006-01-01
The soft measurement technology of flame temperature field is an efficient method to learn the combustion status in furnace. Generally, it reconstructs the temperature field in furnace through the image of flame, which is a process to solve radiative inverse problem. In this paper, the flame of pulverized coal is considered as 3-D, absorbing, emitting,and anisotropically scattering non-gray medium. Through the study on inverse problem of radiative heat transfer, the temperature field in this kind of medium has been reconstructed. The mechanism of 3-D radiative heat transfer in a rectangular media, which is 2 m × 3 m × 5 m and full of CO2, N2 and carbon particles, is studied with Monte Carlo method. The 3-D temperature field in this rectangular space is reconstructed and the influence of particles density profile is discussed.
Institute of Scientific and Technical Information of China (English)
Huaping Gong; Zhiwei Lü; Dianyang Lin; Songjiang Liu
2007-01-01
By adopting noise initiation model of stimulated Brillouin scattering (SBS), the influence of phonon lifetime and gain coefficient of medium on power limiting characteristic is numerically investigated. Through using actual parameters of three media, CCl4, acetone, and CS2, the waveforms of transmitted pulses are simulated. The result shows that different media have little effect on the front peak of waveform,while have an obvious effect on the height of power limiting platform. When the medium which has short phonon lifetime and small gain coefficient is used, the height of power limiting platform is comparatively high. In experiment, by focusing 1064-nm, 8-ns, 18-mJ pulses into these three media, the waveforms of transmitted pulses are obtained. The experimental results are in good agreement with conclusions of theoretical simulations.
Okamoto, Hajime; Sato, Kaori; Makino, Toshiyuki; Nishizawa, Tomoaki; Sugimoto, Nobuo; Jin, Yoshitaka; Shimizu, Atsushi
2016-06-01
We have developed the Multiple Field of view Multiple Scattering Polarization Lidar (MFMSPL) system for the study of optically thick low-level clouds. It has 8 telescopes; 4 telescopes for parallel channels and another 4 for perpendicular channels. The MFMSPL is the first lidar system that can measure depolarization ratio for optically thick clouds where multiple scattering is dominant. Field of view of each channel was 10mrad and was mounted with different angles ranging from 0 mrad (vertical) to 30mrad. And footprint size from the total FOV was achieved to be close to that of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) lidar at the altitude of 1km in order to reproduce similar degree of multiple scattering effects as observed from space. The MFMSPL has started observations since June 2014 and has been continuously operated at National Institute for Environmental Studies (NIES) in Tsukuba, Japan. Observations proved expected performance such that measured depolarization ratio was comparable to the one observed by CALIPSO lidar.
Li, Jia; Chang, Liping; Chen, Feinan
2016-12-01
Based on the first-order Born approximation, the correlation between intensity fluctuations is derived for a partially coherent, electromagnetic plane wave scattering from a spatially quasi-homogeneous medium. Young's pinholes are utilized to control the degree of coherence of the incident field. For the electromagnetic scattering case, it is shown that the CIF of the scattered field strongly depends on the degree of polarization of the incident wave, Young's pinhole parameter, effective radius and correlation length of the medium. The influences of these parameters on the CIF distributions are revealed by numerical calculations.
Multiple scattering of proton via stochastic differential equations
Energy Technology Data Exchange (ETDEWEB)
Kia, M.R.; Noshad, Houshyar, E-mail: hnoshad@aut.ac.ir
2015-08-01
Multiple scattering of protons through a target is explained by a set of coupled stochastic differential equations. The motion of protons in matter is calculated by analytical random sampling from Moliere and Landau probability density functions (PDF). To satisfy the Vavilov theory, the moments for energy distribution of a 49.1 MeV proton beam in aluminum target are obtained. The skewness for the PDF of energy demonstrates that the energy distribution of protons in thin thickness becomes a Landau function, whereas, by increasing the thickness of the target it does not follow a Gaussian function completely. Afterwards, the depth-dose distributions are calculated for a 60 MeV proton beam traversing soft tissue and for a 160 MeV proton beam travelling through water. The results prove that when elastic scattering is taken into account, the Bragg-peak position is decreased, while the dose deposited in the Bragg region is increased. The results obtained in this article are benchmarked by comparison of our results with the experimental data reported in the literature.
Ultrafast collinear scattering and carrier multiplication in graphene.
Brida, D; Tomadin, A; Manzoni, C; Kim, Y J; Lombardo, A; Milana, S; Nair, R R; Novoselov, K S; Ferrari, A C; Cerullo, G; Polini, M
2013-01-01
Graphene is emerging as a viable alternative to conventional optoelectronic, plasmonic and nanophotonic materials. The interaction of light with charge carriers creates an out-of-equilibrium distribution, which relaxes on an ultrafast timescale to a hot Fermi-Dirac distribution, that subsequently cools emitting phonons. Although the slower relaxation mechanisms have been extensively investigated, the initial stages still pose a challenge. Experimentally, they defy the resolution of most pump-probe setups, due to the extremely fast sub-100 fs carrier dynamics. Theoretically, massless Dirac fermions represent a novel many-body problem, fundamentally different from Schrödinger fermions. Here we combine pump-probe spectroscopy with a microscopic theory to investigate electron-electron interactions during the early stages of relaxation. We identify the mechanisms controlling the ultrafast dynamics, in particular the role of collinear scattering. This gives rise to Auger processes, including charge multiplication, which is key in photovoltage generation and photodetectors.
Fainman, Yeshaiahu; Yang, Mu-Han; Abashin, Maxim; Saisan, Payam; Tian, Peifang; Ferri, Christopher; Devor, Anna
2016-10-01
Non-degenerate 2-photon excitation of a fluorophore with two laser beams of different photon energies may offer independent degree of freedom in tuning of the photon flux (i.e., the power) for each beam. Wereport a practical demonstration that the emission intensity of a fluorophore excited in the non-degenerate regime in scattering medium is more efficient than the commonly used degenerate 2-photon excitation. In our experiments we use spatially and temporally aligned Ti:Sapphiremode-locked laser and optical parametric oscillator beams operating at near infrared (NIR) and short-wavelength infrared (SWIR) optical frequencies, respectively. The non-degenerate 2-photon excitation mechanism takes advantage of the infrared wavelengths used in 3-photon microscopy to achieve increased penetration depth, while preserving relatively high 2-photon excitation cross section, exceeding that achievable with the 3-photon excitation. Importantly, independent control of power for each beam implies that the flux requirement for the higher photon energy NIR beam, which experiences higher scattering in biological tissue, can be relaxed at the expense of increasing the flux of the lower photon energy SWIR beam which experiences lower scattering, thus promising deeper penetration with higher efficiency of excitation.Applications for in vivo brain imaging will be also discussed.
Singh, Atul K; Bhunia, Arun K
2016-01-01
Enterobacteriaceae family comprised pathogens and commensals and has a significant impact on food safety and public health. Enterobacteriaceae is often enumerated and presumptively identified on chromogenic media, such as CHROMagar(TM) Orientation medium based on colony profile; however, classification is highly arbitrary, and some could not be differentiated due to similar chromogen production. Here, we investigated the ability of the laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology) for rapid screening and differentiation of colonies of the major bacterial genera from Enterobacteriaceae on CHROMagar(TM) Orientation. A total of 36 strains representing 12 genera and 15 species were used to generate colony scatter image library that comprised 1683 scatter images. This library was used to differentiate mixed cultures of Enterobacteriaceae family - Klebsiella pneumoniae, Enterobacter spp., Citrobacter freundii and Serratia marcescens (KECS group); Proteus mirabilis, Morganella morganii and Providencia rettgeri (PMP group); and non-Enterobacteriaceae family: Pseudomonas aeruginosa, Acinetobacter spp. and Staphylococcus aureus (PAS group) - and data show high accuracy (83-100%) for intra-group classification of colonies in 10-22 h or even before visible production of chromogens. BARDOT successfully differentiated the major genera, including the ones that do not produce visually distinguishable chromogens on CHROMagar(TM) Orientation, providing a label-free, real-time on-plate colony screening tool for Enterobacteriaceae.
The effect of multiple scattering on the aspect sensitivity and polarization of radio auroral echoes
Energy Technology Data Exchange (ETDEWEB)
Donovan, E.F.; Moorcroft, D.R. (Western Ontario, University, London (Canada))
1992-04-01
A Monte Carlo model of radio wave scattering in the auroral electrojet has been developed to investigate multiple scattering of radio auroral echoes. Using this model, predictions of the aspect angle behavior of first-, second-, and third-order scattered power have been made. The results indicate that multiple scattering may be an important effect for VHF radars which observe the auroral E region at large magnetic aspect angles. The model shows that linearly polarized radio waves can become depolarized because of multiple scattering if the radio transmitter is horizontally polarized but not if the radio transmitter is vertically polarized. 52 refs.
Multiplicity moments in deep inelastic scattering at HERA
Chekanov, S; Krakauer, D A; Magill, S; Musgrave, B; Pellegrino, A; Repond, J; Stanek, R; Yoshida, R; Mattingly, M C K; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Cara Romeo, G; Cifarelli, Luisa; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Giusti, P; Iacobucci, G; Levi, G; Margotti, A; Massam, Thomas; Nania, R; Palmonari, F; Pesci, A; Sartorelli, G; Zichichi, A; Aghuzumtsyan, G; Brock, I; Goers, S; Hartmann, H; Hilger, E; Irrgang, P; Jakob, H P; Kappes, A; Katz, U F; Kerger, R; Kind, O; Paul, E; Rautenberg, J; Schnurbusch, H; Stifutkin, A; Tandler, J; Voss, K C; Weber, A; Wieber, H; Bailey, D S; Brook, N H; Cole, J E; Foster, B; Heath, G P; Heath, H F; Robins, S A; Rodrigues, E; Scott, J; Tapper, R J; Wing, M; Capua, M; Mastroberardino, A; Schioppa, M; Susinno, G; Jeoung, H Y; Kim, J Y; Lee, J H; Lim, I T; Ma, K J; Pac, M Y; Caldwell, A; Helbich, M; Liu, W; Liu, X; Mellado, B; Paganis, S; Sampson, S; Schmidke, W B; Sciulli, F; Chwastowski, J; Eskreys, Andrzej; Figiel, J; Klimek, K H; Olkiewicz, K; Przybycien, M B; Stopa, P; Zawiejski, L; Bednarek, B; Jelen, K; Kisielewska, D; Kowal, A M; Kowal, M; Kowalski, T; Mindur, B; Rulikowska-Zarebska, E; Suszycki, L; Szuba, D; Kotanski, Andrzej; Bauerdick, L A T; Behrens, U; Borras, K; Chiochia, V; Crittenden, James Arthur; Dannheim, D; Desler, K; Drews, G; Fox-Murphy, A; Fricke, U; Geiser, A; Göbel, F; Göttlicher, P; Graciani, R; Haas, T; Hain, W; Hartner, G F; Hebbel, K; Hillert, S; Koch, W; Kötz, U; Kowalski, H; Labes, H; Löhr, B; Mankel, R; Martens, J; Martínez, M; Milite, M; Moritz, M; Notz, D; Petrucci, M C; Polini, A; Savin, A A; Schneekloth, U; Selonke, F; Stonjek, S; Wolf, G; Wollmer, U; Whitmore, J J; Wichmann, R; Youngman, C; Zeuner, W; Coldewey, C; López-Duran-Viani, A; Meyer, A; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, Andreas; Benen, A; Coppola, N; Markun, P; Raach, H; Wölfle, S; Bell, M; Bussey, Peter J; Doyle, A T; Glasman, C; Lee, S W; Lupi, A; McCance, G J; Saxon, D H; Skillicorn, Ian O; Bodmann, B; Gendner, N; Holm, U; Salehi, H; Wick, K; Yildirim, A; Ziegler, A; Carli, T; Garfagnini, A; Gialas, I; Lohrmann, E; Foudas, C; Goncalo, R; Long, K R; Metlica, F; Miller, D B; Tapper, A D; Walker, R; Cloth, P; Filges, D; Ishii, T; Kuze, M; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Ahn, S H; Lee, S B; Park, S K; Lim, H; Son, D; Barreiro, F; García, G; González, O; Labarga, L; Del Peso, J; Redondo, I; Terron, J; Vázquez, M E; Barbi, M S; Corriveau, F; Padhi, S; Stairs, D G; Tsurugai, T; Antonov, A; Bashkirov, V; Danilov, P; Dolgoshein, B A; Gladkov, D; Sosnovtsev, V V; Suchkov, S; Dementiev, R K; Ermolov, P F; Golubkov, Yu A; Katkov, I I; Khein, L A; Korotkova, N A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Solomin, A N; Vlasov, N N; Zotkin, S A; Bokel, C; Botje, M; Engelen, J; Grijpink, S; Koffeman, E; Kooijman, P M; Schagen, S; Van Sighem, A; Tassi, E; Tiecke, H G; Tuning, N; Velthuis, J J; Vossebeld, Joost Herman; Wiggers, L; De Wolf, E; Brümmer, N; Bylsma, B; Durkin, L S; Gilmore, J; Ginsburg, C M; Kim, C L; Ling, T Y; Boogert, S; Cooper-Sarkar, A M; Devenish, R C E; Ferrando, J; Grosse-Knetter, J; Matsushita, T; Rigby, M; Ruske, O; Sutton, M R; Walczak, R; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Limentani, S; Longhin, A; Parenti, A; Posocco, M; Stanco, L; Turcato, M; Adamczyk, L; Iannotti, L; Oh, B Y; Saull, P R B; Toothacker, W S; Iga, Y; D'Agostini, Giulio; Marini, G; Nigro, A; Cormack, C; Hart, J C; McCubbin, N A; Epperson, D E; Heusch, C A; Sadrozinski, H F W; Seiden, A; Williams, D C; Park, I H; Pavel, N; Abramowicz, H; Dagan, S; Gabareen, A; Kananov, S; Kreisel, A; Levy, A; Abe, T; Fusayasu, T; Kohno, T; Umemori, K; Yamashita, T; Hamatsu, R; Hirose, T; Inuzuka, M; Kitamura, S; Matsuzawa, K; Nishimura, T; Arneodo, M; Cartiglia, N; Cirio, R; Costa, M; Ferrero, M I; Maselli, S; Monaco, V; Peroni, C; Ruspa, M; Sacchi, R; Solano, A; Staiano, A; Bailey, D C; Fagerstroem, C P; Galea, R; Koop, T; Levman, G M; Martin, J F; Mirea, A; Sabetfakhri, A; Butterworth, J M; Gwenlan, C; Hayes, M E; Heaphy, E A; Jones, T W; Lane, J B; West, B J; Ciborowski, J; Ciesielski, R; Grzelak, G; Nowak, R J; Pawlak, J M; Plucinsky, P P; Smalska, B; Tymieniecka, T; Ukleja, J; Zakrzewski, J A; Adamus, M; Sztuk, J; Deppe, O; Eisenberg, Y; Gladilin, L K; Hochman, D; Karshon, U; Breitweg, J; Chapin, D; Cross, R; Kcira, D; Lammers, S; Reeder, D D; Smith, W H; Deshpande, A A; Dhawan, S K; Straub, V W; Hughes, P B; Bhadra, S; Catterall, C D; Frisken, W R; Hall-Wilton, R; Khakzad, M; Menary, S R
2001-01-01
Multiplicity moments of charged particles in deep inelastic E+P scattering have been measured with the ZEUS detector at HERA using an integrated luminosity of 38.4 pb^{-1}$. The moments for Q^2 > 1000 GeV^2 were studied in the current region of the Breit frame. The evolution of the moments was investigated as a function of restricted regions in polar angle and, for the first time, both in the transverse momentum and in absolute momentum of final-state particles. Analytic perturbative QCD predictions in conjunction with the hypothesis of Local Parton-Hadron Duality (LPHD) reproduce the trends of the moments in polar-angle regions, although some discrepancies are observed. For the moments restricted either in transverse or absolute momentum, the analytic results combined with the LPHD hypothesis show considerable deviations from the measurements. The study indicates a large influence of the hadronisation stage on the multiplicity distributions in the restricted phase-space regions studied here, which is inconsi...
Institute of Scientific and Technical Information of China (English)
李小文; 倪文革; 胡宝新; C.Woodcock; A.Strahler
1996-01-01
Radiative transfer theories are usually used to calculate light transmitted and reflected on a layer of homogeneous medium.But if the layer has limited optical thickness and a non-Lamhertian lower bound,the multiple bouncing between the layer and the lower bound will be coupled with the multiple scattering within the layer,thus making the solution very complicated.Through atmospheric correction for FOS MODIS MISR BRDF product and modeling shortwave absorption of snow under forest canopies,it is found that two complicated and apparently different cases can he handled similarly by decoupling the problem into two simpler and more basic formulations.i.e anahtical approximations ot path scattering i.e assuming a perfect absorbing lower bound: and the multiple bouncing between the layer and ils non-Lamhertian lower bound.
Multiple exchange and high-energy fixed-angle scattering
Halliday, I G; Orzalesi, C A; Tau, M
1975-01-01
The application of the eikonal ansatz to fermion fermion elastic scattering with Abelian vector gluon exchanges is discussed. The behaviours of the elastic scattering amplitude and the elastic form factor are considered and an important mechanism for fixed angle high energy elastic scattering is identified. (6 refs).
Enhancement of the visibility of objects located below the surface of a scattering medium
Demos, Stavros
2013-11-19
Techniques are provided for enhancing the visibility of objects located below the surface of a scattering medium such as tissue, water and smoke. Examples of such an object include a vein located below the skin, a mine located below the surface of the sea and a human in a location covered by smoke. The enhancement of the image contrast of a subsurface structure is based on the utilization of structured illumination. In the specific application of this invention to image the veins in the arm or other part of the body, the issue of how to control the intensity of the image of a metal object (such as a needle) that must be inserted into the vein is also addressed.
Enhancement of the visibility of objects located below the surface of a scattering medium
Energy Technology Data Exchange (ETDEWEB)
Demos, Stavros
2013-11-19
Techniques are provided for enhancing the visibility of objects located below the surface of a scattering medium such as tissue, water and smoke. Examples of such an object include a vein located below the skin, a mine located below the surface of the sea and a human in a location covered by smoke. The enhancement of the image contrast of a subsurface structure is based on the utilization of structured illumination. In the specific application of this invention to image the veins in the arm or other part of the body, the issue of how to control the intensity of the image of a metal object (such as a needle) that must be inserted into the vein is also addressed.
Non-degenerate 2-photon excitation in scattering medium for fluorescence microscopy
Yang, Mu-Han; Saisan, Payam A; Tian, Peifang; Ferri, Christopher G L; AnnaDevor,; Fainman, Yeshaiahu
2016-01-01
Non-degenerate 2-photon excitation (ND-2PE) of a fluorophore with two laser beams of different photon energies offers an independent degree of freedom in tuning of the photon flux for each beam. This feature takes advantage of the infrared wavelengths used in 3-photon microscopy to achieve an increased penetration depth, while preserving a relatively high degenerate 2-photon excitation (D-2PE) cross section, exceeding that achievable with 3-photon excitation. Here, using spatially and temporally aligned Ti:Sapphire laser and optical parametric oscillator beams operating at near infrared (NIR) and short-wavelength infrared (SWIR) optical frequencies, respectively, we provide a practical demonstration that the emission intensity of a fluorophore excited in the non-degenerate regime in a scattering medium is more efficient than the commonly used D-2PE.
DEFF Research Database (Denmark)
Kristensen, Philip Trøst; Lodahl, Peter; Mørk, Jesper
2010-01-01
We present an accurate, stable, and efficient solution to the Lippmann–Schwinger equation for electromagnetic scattering in two dimensions. The method is well suited for multiple scattering problems and may be applied to problems with scatterers of arbitrary shape or non-homogenous background mat...
Multiple scattering filter: Application to plane defect detection in a nickel alloy
Trottier, Camille; Shahjhan, Sharfine; Schumm, Andreas; Aubry, Alexandre; Derode, Arnaud
2016-02-01
The ultrasonic inspection of polycrystalline media remains a challenge. The high noise levels due to interaction between the wave and the microstructure limit the efficiency of classical ultrasonic techniques to detect a defect in a coarse grain structure. The aim of this work is to reduce the influence of multiple scattering in order to increase the information obtained from the defect. The technique introduced here is based on array probes for the acquisition of the medium's response matrix by full matrix capture, after which a filter based on random matrix theory is applied. Here an improvement of this technique is applied on nickel-based alloy mock-ups that present an unfavourable grain structure and well known bulk and plane defects. The results in normal incidence and with an angle array probe of 128 elements and 5 MHz of central frequency are compared to classical phased array probe techniques.
Khazaie, Shahram; Cottereau, Régis; Clouteau, Didier
2016-05-01
In the weakly heterogeneous regime of elastic wave propagation through a random medium, transport and diffusion models for the energy densities can be set up. In the isotropic case, the scattering cross sections are explicitly known as a function of the wavenumber and the correlations of the Lamé parameters and density. In this paper, we discuss the precise influence of the correlation structure on the scattering cross sections, mean free paths and diffusion parameter, and separate that influence from that of the correlation length and variance. We also analyze the convergence rates towards the low- and high-frequency ranges. For all analyses, we consider five different correlation structures that allow us to explore a wide range of behaviors. We identify that the controlling factors for the low-frequency behavior are the value of the Power Spectral Density Function (PSDF) and its first non-vanishing derivative at the origin. In the high frequency range, the controlling factor is the third moment of the PSDF (which may be unbounded).
Chen, Xueli; Zhang, Qitan; Yang, Defu; Liang, Jimin
2014-01-01
To provide an ideal solution for a specific problem of gastric cancer detection in which low-scattering regions simultaneously existed with both the non- and high-scattering regions, a novel hybrid radiosity-SP3 equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP3) was combined with the radiosity equation to describe the bioluminescent light propagation in tissues, which provided acceptable accuracy for the turbid medium with both low- and non-scattering regions. The performance of the algorithm was evaluated with digital mouse based simulations and a gastric cancer-bearing mouse based in situ experiment. Primary results demonstrated the feasibility and superiority of the proposed algorithm for the turbid medium with low- and non-scattering regions.
A dense medium electromagnetic scattering model for the InSAR correlation of snow
Lei, Yang; Siqueira, Paul; Treuhaft, Robert
2016-05-01
Snow characteristics, such as snow water equivalent (SWE) and snow grain size, are important characteristics for the monitoring of the global hydrological cycle and as indicators of climate change. This paper derives an interferometric synthetic aperture radar (InSAR) scattering model for dense media, such as snow, which takes into account multiple scattering effects through the Quasi-Crystalline Approximation. The result of this derivation is a simplified version of the InSAR correlation model derived for relating the InSAR correlation measurements to the snowpack characteristics of grain size, volume fraction, and layer depth as well as those aspects of the volume-ground interaction that affects the interferometric observation (i.e., the surface topography and the ratio of ground-to-volume scattering). Based on the model, the sensitivity of the InSAR correlation measurements to the snow characteristics is explored by simulation. Through this process, it is shown that Ka-band InSAR phase has a good sensitivity to snow grain size and volume fraction, while for lower frequency signals (Ku-band to L-band), the InSAR correlation magnitude and phase have a sensitivity to snow depth. Since the formulation depends, in part, on the pair distribution function, three functional forms of the pair distribution function are implemented and their effects on InSAR phase measurements compared. The InSAR scattering model described in this paper is intended to be an observational prototype for future Ka-band and L-band InSAR missions, such as NASA's Surface Water and Ocean Topography and NASA-ISRO Synthetic Aperture Radar missions, planned for launch in the 2020-2021 time frame. This formulation also enables further investigation of the InSAR-based snow retrieval approaches.
Study on two-cell stimulated Brillouin scattering system with mixture medium
Institute of Scientific and Technical Information of China (English)
HASI Wuliji; L(U) ZhiWei; LI Qiang; BA DeXin; HE WeiMing
2007-01-01
In this paper, a method of choosing mixture medium in two-cell stimulated Brillouin scattering (SBS) system to improve the system performance is proposed. The Brillouin frequency shift (BFS) of mixture medium varies with the mixing ratio and thus the difference of the BFS between the two cells can be eliminated. The two-cell SBS system with acetone (C3H6O) in its generator cell and mixture liquid of CCl4/C2Cl4 in its amplifier cell is investigated. The C3H6O has a high optical break- down threshold and the mixture liquid of CCl4/C2Cl4 has a small absorption coefficient and the same BFS as that of C3H6O when the volume fraction of CCl4 is 4%. Compared with two-cell SBS system with the same liquid (C2Cl4) or different liquid (C3H6O and C2Cl4) in generator and amplifier cell, the SBS system with mixture liquid (CCl4/C2Cl4) in amplifier cell and C3H6O in generator cell improves the power-load, energy reflectivity (ER), phase conjugation (PC) fidelity and ER stability.
Cylindrical-Wave Approach for Electromagnetic Scattering by Subsurface Targets in a Lossy Medium
Frezza, F.; Pajewski, L.; Ponti, C.; Schettini, G.; Tedeschi, N.
2012-04-01
The Cylindrical-Wave Approach (CWA) rigorously solves, in the spectral domain, the electromagnetic forward scattering by a finite set of buried two-dimensional perfectly-conducting or dielectric objects [1]-[3]. In this technique, the field scattered by underground objects is represented in terms of a superposition of cylindrical waves. Use is made of the plane-wave spectrum [1] to take into account the interaction of such waves with the planar interface between air and soil, and between different layers eventually present in the ground. In this work we present the progress we recently made to improve the method. In particular, we have faced the fundamental problem of losses in the ground: this is of significant importance in remote sensing applications, since real soils often have complex permittivity and conductivity, and sometimes also a complex permeability. First, a convergent closed-form representation of the cylindrical-wave angular spectrum in a generic lossy medium has been found [4]. To obtain this spectrum, the canonical Sommerfeld representation of the first-kind Hankel function of integer order has been used; its integration path has been modified to ensure the integral convergence for complex values of the wavenumber. Subsequently, the solution to the scattering problem of a plane-wave propagating in air, impinging on the interface with a dissipative medium, and interacting with a buried perfectly-conducting cylinder, has been derived. The developed method may return the field values in each point of the space, both in the near and far zones; moreover it may be applied for any polarization, and for arbitrary values of the cylinder size and of the distance between the cylinder and the air-soil interface. The theoretical solution has been implemented in a Fortran code. The numerical evaluation of the reflected and transmitted cylindrical wave functions in the presence of lossy media was a critical point: we extended the Gaussian adaptive quadrature
Energy Technology Data Exchange (ETDEWEB)
Geach, J. E.; Coppin, K. E. K.; Smith, D. J. B. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Bower, R. G.; Alexander, D. M.; Swinbank, A. M. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bremer, M. N. [School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapin, E. L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Canada, Madrid (Spain); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University Halifax, NS B3H 3J5 (Canada); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Dunlop, J. S.; Koprowski, M. P.; Michałowski, M. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Farrah, D. [Virginia Polytechnic Institute and State University Department of Physics, MC 0435, 910 Drillfield Drive, Blacksburg, VA 24061 (United States); Jenness, T. [Joint Astronomy Centre, 660 North A' ohoku Place University Park, Hilo, HI 96720 (United States); Robson, E. I. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Scott, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Spaans, M. [Kapteyn Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); Van der Werf, P., E-mail: j.geach@herts.ac.uk [Leiden Observatory, Leiden University, PO box 9513, 2300 RA Leiden (Netherlands)
2014-09-20
We report the detection at 850 μm of the central source in SSA22-LAB1, the archetypal 'Lyman-α Blob' (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S {sub 850} = 4.6 ± 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L {sub IR} ≈ 10{sup 12} L {sub ☉}. The position of an active source at the center of a ∼50 kpc radius ring of linearly polarized Lyα emission detected by Hayes et al. suggests that the central source is leaking Lyα photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Lyα morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Lyα line profiles of the two 'lobes' are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Lyα emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Lyα: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?.
Numerical simulations of multiple scattering of the $f-$mode by flux tubes
2013-01-01
We use numerial simulations to study the absorption and phase shift of surface-gravity waves caused by groups of magnetic flux tubes. The dependence of the scattering coefficients with the distance between the tubes and their positions is analyzed for several cases with two or three flux tubes embedded in a quiet Sun atmosphere. The results are compared with those obtained neglecting completely or partially multiple scattering effects. We show that multiple scattering has a significant impact...
Real-space multiple-scattering theory of XMCD including spin-orbit interaction in scattering process
Koide, Akihiro; Niki, Kaori; Sakai, Seiji; Fujikawa, Takashi
2016-05-01
The effects of the spin-orbit interaction on surrounding atoms for XMCD spectra are studied by a real-space multiple-scattering theory. The present numerical calculation for Fe K-edge XMCD spectra from BCC iron demonstrates the importance of the spin-orbit interaction on scattering atoms, which has been disregarded in previous works. These effects will be inevitable for K-edge XMCD analyses of light elements surrounded by heavy magnetic atoms.
Sommer, H.; Ebenau, M.; Spaan, B.; Eichmann, M.
2017-03-01
Previous studies show remarkable differences in the simulation of electron depth dose profiles of ruthenium eye plaques. We examined the influence of the scoring and simulation geometry, the source spectrum and the multiple scattering algorithm on the depth dose profile using GEANT4. The simulated absolute dose deposition agrees with absolute dose data from the manufacturer within the measurement uncertainty. Variations in the simulation geometry as well as the source spectrum have only a small influence on the depth dose profiles. However, the multiple scattering algorithms have the largest influence on the depth dose profiles. They deposit up to 20% less dose compared to the single scattering implementation. We recommend researchers who are interested in simulating low- to medium-energy electrons to examine their simulation under the influence of different multiple scattering settings. Since the simulation and scoring geometry as well as the exact physics settings are best described by the source code of the application, we made the code publicly available.
μ-diff: An open-source Matlab toolbox for computing multiple scattering problems by disks
Thierry, Bertrand; Antoine, Xavier; Chniti, Chokri; Alzubaidi, Hasan
2015-07-01
The aim of this paper is to describe a Matlab toolbox, called μ-diff, for modeling and numerically solving two-dimensional complex multiple scattering by a large collection of circular cylinders. The approximation methods in μ-diff are based on the Fourier series expansions of the four basic integral operators arising in scattering theory. Based on these expressions, an efficient spectrally accurate finite-dimensional solution of multiple scattering problems can be simply obtained for complex media even when many scatterers are considered as well as large frequencies. The solution of the global linear system to solve can use either direct solvers or preconditioned iterative Krylov subspace solvers for block Toeplitz matrices. Based on this approach, this paper explains how the code is built and organized. Some complete numerical examples of applications (direct and inverse scattering) are provided to show that μ-diff is a flexible, efficient and robust toolbox for solving some complex multiple scattering problems.
Robustness of the fractal regime for the multiple-scattering structure factor
Katyal, Nisha; Botet, Robert; Puri, Sanjay
2016-08-01
In the single-scattering theory of electromagnetic radiation, the fractal regime is a definite range in the photon momentum-transfer q, which is characterized by the scaling-law behavior of the structure factor: S(q) ∝ 1 /q df. This allows a straightforward estimation of the fractal dimension df of aggregates in Small-Angle X-ray Scattering (SAXS) experiments. However, this behavior is not commonly studied in optical scattering experiments because of the lack of information on its domain of validity. In the present work, we propose a definition of the multiple-scattering structure factor, which naturally generalizes the single-scattering function S(q). We show that the mean-field theory of electromagnetic scattering provides an explicit condition to interpret the significance of multiple scattering. In this paper, we investigate and discuss electromagnetic scattering by three classes of fractal aggregates. The results obtained from the TMatrix method show that the fractal scaling range is divided into two domains: (1) a genuine fractal regime, which is robust; (2) a possible anomalous scaling regime, S(q) ∝ 1 /qδ, with exponent δ independent of df, and related to the way the scattering mechanism uses the local morphology of the scatterer. The recognition, and an analysis, of the latter domain is of importance because it may result in significant reduction of the fractal regime, and brings into question the proper mechanism in the build-up of multiple-scattering.
Energy Technology Data Exchange (ETDEWEB)
Spurr, Robert [RT Solutions Inc., 9 Channing Street, Cambridge, MA 02138 (United States)], E-mail: rtsolutions@verizon.net; Haan, Johan de; Oss, Roeland van [KNMI, de Bilt (Netherlands); Vasilkov, Alexander [SSAI, Lanham, MD (United States)
2008-02-15
Rotational Raman scattering (RRS) by air molecules in the Earth's atmosphere is predominantly responsible for the Ring effect: Fraunhofer and absorption-feature filling-in observed in UV/visible backscatter spectra. Accurate determination of RRS effects requires detailed radiative transfer (RT) treatment. In this paper, we demonstrate that the discrete-ordinate RT equations may be solved analytically in a multi-layer multiple scattering atmosphere in the presence of RRS treated as a first-order perturbation. Based on this solution, we develop a generic pseudo-spherical RT model LIDORT-RRS for the determination of backscatter radiances with RRS included; the model will generate output at arbitrary viewing geometry and optical thickness. Model comparisons with measured RRS filling-in effects from OMI observations show very good agreement. We examine telluric RRS filling-in effects for satellite-view backscatter radiances in a spectral range covering the ozone Huggins absorption bands. The model is also used to investigate calcium H and K Fraunhofer filling-in through cloud layers in the atmosphere.
A Study of Multiple Scattering in BGO and LYSO Single Crystal Scintillators
Directory of Open Access Journals (Sweden)
Kittipong Seingsanoh
2016-08-01
Full Text Available The angular distribution of multiple Compton scatterings from BGO and LYSO single crystal scintillators was studied at various scattering angles. Gamma photons with 662 keV energy, acquired from a 137Cs source, were used. The scattered photons were detected by a 51mm × 51mm NaI(Tl scintillation detector. The overall energy correlated to the total number of scattered incidents was analytically reconstructed. The research found that the multiply scattered incidents had the same energy as received from the singly scattered distribution, as the attribution of multiply scattered incidents near the 90° scattering angle revealed. The research results were in agreement with the theoretical calculations.
DEFF Research Database (Denmark)
de Lasson, Jakob Rosenkrantz; Kristensen, Philip Trøst; Mørk, Jesper
2012-01-01
We present a multiple-scattering formalism for simulating scattering of electromagnetic waves on spherical inhomogeneities in 3D. The formalism is based on the Lippmann-Schwinger equation and the electromagnetic Green's tensor and applies an expansion of the electric field on spherical wavefuncti......We present a multiple-scattering formalism for simulating scattering of electromagnetic waves on spherical inhomogeneities in 3D. The formalism is based on the Lippmann-Schwinger equation and the electromagnetic Green's tensor and applies an expansion of the electric field on spherical...
Silver sulphide growth on Ag(111): A medium energy ion scattering study
Window, A. J.; Hentz, A.; Sheppard, D. C.; Parkinson, G. S.; Woodruff, D. P.; Noakes, T. C. Q.; Bailey, P.
2010-08-01
The interaction of S 2 with Ag(111) under ultra-high vacuum conditions has been investigated by medium energy ion scattering (MEIS). 100 keV He + MEIS measurements provide a direct confirmation of a previous report, based on thermal desorption, that the growth of multilayer films of Ag 2S occurs through a continuous corrosion process. These films show a commensurate (√7 × √7)R19° unit mesh in low energy electron diffraction, consistent with the epitaxial growth of (111) layers of the high-temperature F-cubic phase of Ag 2S. The substantial range of co-existing film thicknesses found indicates that the growth must be in the form of variable-thickness islands. The use of 100 keV H + incident ions leads to a very rapid decrease in the sulphide film thickness with increasing exposure that we attribute to an unusual chemical leaching, with implanted H atoms interacting with S atoms and desorption of H 2S from the surface.
Strudley, Tom; Mills, Ben; Muskens, Otto L
2013-01-01
Wavefront shaping of light fields has opened up a wealth of new applications in imaging and communication in highly multimode environments [1-11]. By mixing of the modes with optimized phases and amplitudes it is possible to focus light through - or even inside - opaque scattering media [1,2]. Here we present work demonstrating ultrafast control of such an optimized wavefront transmitted through a dense disordered mat of semiconductor nanowires by exploiting their inherent nonlinearity. Modulations of the peak intensity of up to 63% (4.3 dB) are induced by optical pumping as a result of a combination of multimode dephasing and induced absorption. Next to ultrafast dephasing of the shaped field, we show that it is possible to dynamically rephase the light fields into an optimized spot by means of pulsed nonlinear excitation of the medium. We obtain an enhancement of the peak to background ratio of the optimized spot resulting from rephasing of up to 18%. While our results are obtained for three dimensional med...
A fast method to compute Three-Dimensional Infrared Radiative Transfer in non scattering medium
Makke, Laurent; Musson-Genon, Luc; Carissimo, Bertrand
2014-05-01
The Atmospheric Radiation field has seen the development of more accurate and faster methods to take into account absoprtion in participating media. Radiative fog appears with clear sky condition due to a significant cooling during the night, so scattering is left out. Fog formation modelling requires accurate enough method to compute cooling rates. Thanks to High Performance Computing, multi-spectral approach of Radiative Transfer Equation resolution is most often used. Nevertheless, the coupling of three-dimensionnal radiative transfer with fluid dynamics is very detrimental to the computational cost. To reduce the time spent in radiation calculations, the following method uses analytical absorption functions fitted by Sasamori (1968) on Yamamoto's charts (Yamamoto,1956) to compute a local linear absorption coefficient. By averaging radiative properties, this method eliminates the spectral integration. For an isothermal atmosphere, analytical calculations lead to an explicit formula between emissivities functions and linear absorption coefficient. In the case of cooling to space approximation, this analytical expression gives very accurate results compared to correlated k-distribution. For non homogeneous paths, we propose a two steps algorithm. One-dimensional radiative quantities and linear absorption coefficient are computed by a two-flux method. Then, three-dimensional RTE under the grey medium assumption is solved with the DOM. Comparisons with measurements of radiative quantities during ParisFOG field (2006) shows the cability of this method to handle strong vertical variations of pressure/temperature and gases concentrations.
Geach, J E; Alexander, D M; Blain, A W; Bremer, M; Chapin, E L; Chapman, S C; Clements, D L; Coppin, K E K; Dunlop, J S; Farrah, D; Jenness, T; Koprowski, M P; Michalowski, M J; Robson, E I; Scott, D; Smith, D J B; Spaans, M; Swinbank, A M; van der Werf, P
2014-01-01
We report the detection at 850um of the central source in SSA22-LAB1, the archetypal Lyman-alpha Blob (LAB), a 100kpc-scale radio-quiet emission-line nebula at z=3.1. The flux density of the source, $S_{850}=4.6\\pm1.1$mJy implies the presence of a galaxy, or group of galaxies, with a total luminosity of $L_{\\rm IR}\\approx10^{12}L_\\odot$. The position of an active source at the center of a ~50kpc-radius ring of linearly polarized Ly-alpha emission detected by Hayes et al. (2011) suggests that the central source is leaking Ly-alpha photons preferentially in the plane of the sky, which undergo scattering in HI clouds at large galactocentric radius. The Ly-alpha morphology around the submillimeter detection is reminiscent of biconical outflow, and the average Ly-alpha line profiles of the two `lobes' are dominated by a red peak, expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evi...
Strain relaxation of CdTe on Ge studied by medium energy ion scattering
Pillet, J. C.; Pierre, F.; Jalabert, D.
2016-10-01
We have used the medium energy ion scattering (MEIS) technique to assess the strain relaxation in molecular-beam epitaxial (MBE) grown CdTe (2 1 1)/Ge (2 1 1) system. A previous X-ray diffraction study, on 10 samples of the same heterostructure having thicknesses ranging from 25 nm to 10 μm has allowed the measurement of the strain relaxation on a large scale. However, the X-ray diffraction measurements cannot achieve a stress measurement in close proximity to the CdTe/Ge interface at the nanometer scale. Due to the huge lattice misfit between the CdTe and Ge, a high degree of disorder is expected at the interface. The MEIS in channeling mode is a good alternative in order to profile defects with a high depth resolution. For a 21 nm thick CdTe layer, we observed, at the interface, a high density of Cd and/or Te atoms moved from their expected crystallographic positions followed by a rapid recombination of defects. Strain relaxation mechanisms in the vicinity of the interface are discussed
Interfacial Reactions of Metal Oxide Stack Dielectrics Studied with Medium Energy Ion Scattering
Copel, M.; Reuter, M. C.; Cartier, E.; Callegari, A.; Guha, S.; Gousev, E. P.; Jamison, P.; Narayanan, V.; Neumayer, D.
2003-03-01
Application of a metal oxide as a gate dielectric for Si CMOS requires an understanding of the materials reactions that occur with thermal processing. A number of metal oxides have been examined for use as a gate dielectric, with varying degrees of reactivity. Reactions between Y and La oxides and SiO2 are facile, forming interfacial silicates that can extend many nanometers. For the case of Y_2O_3, this reaction can completely consume an SiO2 or SiO_xNy buffer layer, resulting in a silicate/Si(001) interface with no interfacial layer detectable by medium energy ion scattering (MEIS). In contrast, Zr and Hf oxides tend to remain unmixed with SiO_2, due to either sluggish kinetics or instability of the silicates. Interfacial reaction zones can be extremely limited, extending less than 1 nanometer for chemically deposited films. We will report MEIS results for gate dielectric stacks, using in situ processing to illustrate the materials reactions that are commonly encountered.
An SVD Investigation of Modeling Scatter in Multiple Energy Windows for Improved SPECT Images.
Kadrmas, Dan J; Frey, Eric C; Tsui, Benjamin M W
1996-08-01
In this work singular value decomposition (SVD) techniques are used to investigate how the use of low energy photons and multiple energy windows affects the noise properties of Tc-99m SPECT imaging. We have previously shown that, when modeling scatter in the projector and backprojector of iterative reconstruction algorithms, simultaneous reconstruction from multiple energy window data can result in very different noise characteristics. Further, the properties depend upon the width and number of energy windows used. To investigate this further, we have generated photon transport matrices using models for scatter, an elliptical phantom containing cold rods of various sizes, and a number of multiple energy window acquisition schemes. Transfer matrices were also generated for the cases of perfect scatter rejection and ideal scatter subtraction. The matrices were decomposed using SVD, and signal power and projection space variance spectra were computed using the basis formed by the left singular vectors. Results indicate very different noise levels for the various energy window combinations. The perfect scatter rejection case resulted in the lowest variance spectrum, and reconstruction-based scatter compensation performed better than the scatter subtraction case. When including lower energy photons in reconstruction-based scatter compensation, using a series of multiple energy windows outperformed a single large energy window. One multiple window combination is presented which achieves a lower variance spectrum than the standard 20% energy window, indicating the potential for using low energy photons to improve the noise characteristics of SPECT images.
Acosta, Sebastian; Villamizar, Vianey
2010-08-01
The applicability of the Dirichlet-to-Neumann technique coupled with finite difference methods is enhanced by extending it to multiple scattering from obstacles of arbitrary shape. The original boundary value problem (BVP) for the multiple scattering problem is reformulated as an interface BVP. A heterogenous medium with variable physical properties in the vicinity of the obstacles is considered. A rigorous proof of the equivalence between these two problems for smooth interfaces in two and three dimensions for any finite number of obstacles is given. The problem is written in terms of generalized curvilinear coordinates inside the computational region. Then, novel elliptic grids conforming to complex geometrical configurations of several two-dimensional obstacles are constructed and approximations of the scattered field supported by them are obtained. The numerical method developed is validated by comparing the approximate and exact far-field patterns for the scattering from two circular obstacles. In this case, for a second order finite difference scheme, a second order convergence of the numerical solution to the exact solution is easily verified.
Numerical simulations of multiple scattering of the $f-$mode by flux tubes
Felipe, T; Birch, A C
2013-01-01
We use numerial simulations to study the absorption and phase shift of surface-gravity waves caused by groups of magnetic flux tubes. The dependence of the scattering coefficients with the distance between the tubes and their positions is analyzed for several cases with two or three flux tubes embedded in a quiet Sun atmosphere. The results are compared with those obtained neglecting completely or partially multiple scattering effects. We show that multiple scattering has a significant impact on the absorption measurements and tends to reduce the phase shift. We also consider more general cases of ensembles of randomly distributed flux tubes, and we have evaluated the effects on the scattering measurements of changing the number of tubes included in the bundle and the average distance between flux tubes. We find that for the longest wavelength incoming waves multiple scattering enhances the absorption, and its efficiency increases with the number of flux tubes and the reduction of the distance between them.
Analysis of Spent Nuclear Fuel Imaging Using Multiple Coulomb Scattering of Cosmic Muons
Chatzidakis, Stylianos; Tsoukalas, Lefteri H
2016-01-01
Cosmic ray muons passing through matter lose energy from inelastic collisions with electrons and are deflected from nuclei due to multiple Coulomb scattering. The strong dependence of scattering on atomic number Z and the recent developments on position sensitive muon detectors indicate that multiple Coulomb scattering could be an excellent candidate for spent nuclear fuel imaging. Muons present significant advantages over existing monitoring and imaging techniques and can play a central role in monitoring nuclear waste and spent nuclear fuel stored in dense well shielded containers. The main purpose of this paper is to investigate the applicability of multiple Coulomb scattering for imaging of spent nuclear fuel dry casks stored within vertical and horizontal commercial storage dry casks. Calculations of muon scattering were performed for various scenarios, including vertical and horizontal fully loaded dry casks, half loaded dry casks, dry casks with one row of fuel assemblies missing, dry casks with one fu...
Study of multiple scattering in high magnetic fields
Kaplan, Daniel M
2011-01-01
Muon cooling for a neutrino factory or muon collider can be achieved using low-Z absorbers in strong focusing fields. Proposed cooling lattices place absorbers in solenoidal fields ranging up to 30 to 40T. The cooling performance of these lattices is determined by the interplay of ionization energy loss and Moliere scattering, but Bethe's classic treatment of Moliere scattering ignores the helical motion of charged particles in solenoidal fields. When this motion is taken into account, the performance of these lattices can be better than predicted by simulations using the standard treatment.
Two-nucleon scattering in multiple partial waves
Nicholson, Amy; Rinaldi, Enrico; Vranas, Pavlos; Kurth, Thorsten; Joo, Balint; Strother, Mark; Walker-Loud, Andre
2015-01-01
We determine scattering phase shifts for S,P,D, and F partial wave channels in two-nucleon systems using lattice QCD methods. We use a generalization of Luscher's finite volume method to determine infinite volume phase shifts from a set of finite volume ground- and excited-state energy levels on two volumes, V=(3.4 fm)^3 and V=(4.5 fm)^3. The calculations are performed in the SU(3)-flavor limit, corresponding to a pion mass of approximately 800 MeV. From the energy dependence of the phase shifts we are able to extract scattering parameters corresponding to an effective range expansion.
Effects of Multiple Photon Scattering in Deciduous Tree Canopies
2009-12-01
SCATTERING IN DECIDUOUS TREE CANOPIES 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62204F 6. AUTHOR(S...where mh 18= , 16132.0 −= mLm , and 85.0=hzm . Note that the value for mL corresponds to our own experimental results, as will be described in Section 4
The simulation of multiple scattering and its effect on the detection limit of HIBS
Energy Technology Data Exchange (ETDEWEB)
Li, M.M.; O`Connor, D.J. [Newcastle University, Newcastle, NSW (Australia). Dept. of Physics
1998-06-01
With the development of heavy ion backscattering spectrometry (HIBS) for the detection of trace impurities, it is necessary to quantify the multiple scattering contributions to the spectral background. In the present work, the Monte Carlo computer simulation program TRIM has been used to study the backscattering spectrum and the multiple scattering features for heavy ions C, Ne, Si, Ar and Kr impinging on four types of targets: a very thin layer Au with thickness of 10 Angstroms, a 10 Angstroms Au thin layer covering a 50 Angstroms Si thick layer, a 10 Angstroms Au thin layer covering on Si substrate (10000 Angstroms), and a thick target of pure Si with thickness of 10000 Angstroms. By fitting the simulation results we have derived the ratio of signal from the thin Au layer to the background due to multiple scattering. From the simulation results, we found that the Si substrate plays a role in generating the low energy background tail due to ion`s multiple scattering in the substrate. Such a background is generated neither by the thin Au layer nor by the pure Si substrate independently. The corresponding mechanism of multiple scattering in the target can be explained as one large-angle scattering event in Au layer and subsequently several small angle scattering events in the substrate. (authors). 4 refs., 1 tab., 3 figs.
Mounaix, Mickael; Defienne, Hugo; Volpe, Giorgio; Katz, Ori; Grésillon, Samuel; Gigan, Sylvain
2015-01-01
We report broadband characterization of the propagation of light through a multiply scattering medium by means of its Multi-Spectral Transmission Matrix. Using a single spatial light modulator, our approach enables the full control of both spatial and spectral properties of an ultrashort pulse transmitted through the medium. We demonstrate spatiotemporal focusing of the pulse at any arbitrary position and time with any desired spectral shape. Our approach opens new perspectives for fundamental studies of light-matter interaction in disordered media, and has potential applications in sensing, coherent control and imaging.
Cengel, Y. A.; Ozisik, M. N.
1984-08-01
An analytical model is developed for radiation transfer in a plane-parallel slab geometry with anisotropic scattering, spatially varying albedo, reflecting and emitting boundaries, and energy sources within the medium. The albedo is defined in terms of Legendre polynomials and account is taken of the effects of spatial albedo variation on reflectivity and transmissivity of the medium after formulating generalized incident radiation equation. Forward and backward radiation fluxes are then obtained. It is noted that the Legendre polynomials permit inclusion of sufficient numbers of terms to achieve any desired level of accuracy for the albedo.
Reversible storage of multiple light pulses in the EIT atomic medium
Institute of Scientific and Technical Information of China (English)
Shuguang Zhu (祝曙光); Anshi Xu (徐安士); Yu Zhang (张宇); Hong Guo (郭弘); Xuzong Chen (陈徐宗); Deming Wu (吴德明)
2003-01-01
In this paper, we first present a full numerical simulation for the trapping and retrieval procedure of eight continuing "1" Guassian pulses (i.e., "11111111") in the electromagnetically induced transparency (EIT)medium. This simulation shows that an EIT medium has the ability to store multiple light pulses in a shape-preserving way. And we also, for the first time, give the formula evaluating the maximum number of pulses that can be stored by an EIT medium at one time. This work reveals a new possible way to the reversible storage of the photonic information.
Frequency width of open channels in multiple scattering media
Bosch, J.; Goorden, S.A.; Mosk, Allard
2016-01-01
We report optical measurements of the spectral width of open transmission channels in a three-dimensional diffusive medium. The light transmission through a sample is enhanced by efficiently coupling to open transmission channels using repeated digital optical phase conjugation. The spectral
Corrales, Lia
2015-01-01
X-ray bright quasars might be used to trace dust in the circumgalactic and intergalactic medium through the phenomenon of X-ray scattering, which is observed around Galactic objects whose light passes through a sufficient column of interstellar gas and dust. Of particular interest is the abundance of grey dust larger than 0.1 um, which is difficult to detect at other wavelengths. To calculate X-ray scattering from large grains, one must abandon the traditional Rayleigh-Gans approximation. The Mie solution for the X-ray scattering optical depth of the Universe is ~1%. This presents a great difficulty for distinguishing dust scattered photons from the point source image of Chandra, which is currently unsurpassed in imaging resolution. The variable nature of AGN offers a solution to this problem, as scattered light takes a longer path and thus experiences a time delay with respect to non-scattered light. If an AGN dims significantly (> 3 dex) due to a major feedback event, the Chandra point source image will be ...
[Multiple scattering of visible and infrared light by sea fog over wind driving rough sea surface].
Sun, Xian-Ming; Wang, Hai-Hua; Lei, Cheng-Xin; Shen, Jin
2013-08-01
The present paper is concerned with computing the multiple scattering characteristics of a sea fog-sea surface couple system within this context. The single scattering characteristics of sea fog were studied by Mie theory, and the multiple scattering of sunlight by single sea fog layer was studied by radiative transfer theory. The reflection function of a statistically rough ocean surface was obtained using the standard Kirchhoff formulation, with shadowing effects taken into account. The reflection properties of the combined sea fog and ocean surface were obtained employing the adding method, and the results indicated that the reflected light intensity of sea fog increased with the sea background.
Effects Of Aerosol And Multiple Scattering On The Polarization Of The Twilight Sky
Ugolnikov, O S; Maslov, I A
2003-01-01
The paper contains the review of a number of wide-angle polarization CCD-measurements of the twilight sky in V and R color bands with effective wavelengths equal to 550 and 700 nm. The basic factors effecting (usually decreasing) on the polarization of the twilight sky are the atmospheric aerosol scattering and multiple scattering. The method of multiple scattering separation is being considered. The results are compared with the data of numerical simulation of radiation transfer in the atmosphere for different aerosol models. The whole twilight period is divided on the different stages with different mechanisms forming the twilight sky polarization properties.
Multiple scattering dynamics of fermions at an isolated p-wave resonance
Thomas, Ryan; Tiesinga, Eite; Wade, Andrew C J; Blakie, P Blair; Deb, Amita B; Kjærgaard, Niels
2016-01-01
The wavefunction for indistinguishable fermions is anti-symmetric under particle exchange, which directly leads to the Pauli exclusion principle, and hence underlies the structure of atoms and the properties of almost all materials. In the dynamics of collisions between two indistinguishable fermions this requirement strictly prohibits scattering into 90 degree angles. Here we experimentally investigate the collisions of ultracold clouds fermionic $\\rm^{40}K$ atoms by directly measuring scattering distributions. With increasing collision energy we identify the Wigner threshold for p-wave scattering with its tell-tale dumb-bell shape and no $90^\\circ$ yield. Above this threshold effects of multiple scattering become manifest as deviations from the underlying binary p-wave shape, adding particles either isotropically or axially. A shape resonance for $\\rm^{40}K$ facilitates the separate observation of these two processes. The isotropically enhanced multiple scattering mode is a generic p-wave threshold phenomen...
On the theory and simulation of multiple Coulomb scattering of heavy-charged particles.
Striganov, S I
2005-01-01
The Moliere theory of multiple Coulomb scattering is modified to take into account the difference between processes of scattering off atomic nuclei and electrons. A simple analytical expression for angular distribution of charged particles passing through a thick absorber is found. It does not assume any special form for a differential scattering cross section and has a wider range of applicability than a gaussian approximation. A well-known method to simulate multiple Coulomb scatterings is based on treating 'soft' and 'hard' collisions differently. An angular deflection in a large number of 'soft' collisions is sampled using the proposed distribution function, a small number of 'hard' collision are simulated directly. A boundary between 'hard' and 'soft' collisions is defined, providing a precise sampling of a scattering angle (1% level) and a small number of 'hard' collisions. A corresponding simulating module takes into account projectile and nucleus charged distributions and exact kinematics of a projectile-electron interaction.
Calculation of multiple-scattering angular distributions of electrons and positrons
Energy Technology Data Exchange (ETDEWEB)
Negreanu, C. [Paul Scherrer Institute, CH-5232 PSI Villigen (Switzerland); Swiss Federal Institute of Technology (EPFL), CH-1015 Laussane (Switzerland); Llovet, X. [Serveis Cientifico-Tecnics, Universitat de Barcelona, Societat Catalana de Fisica (IEC), Lluis Sole i Sabaris 1-3, ES-08028 Barcelona (Spain); Chawla, R. [Paul Scherrer Institute, CH-5232 PSI Villigen (Switzerland); Swiss Federal Institute of Technology (EPFL), CH-1015 Laussane (Switzerland); Salvat, F. [Facultat de Fisica (ECM), Universitat de Barcelona, Societat Catalana de Fisica (IEC), Diagonal 647, ES-08028 Barcelona (Spain)]. E-mail: cesc@ecm.ub.es
2005-12-15
A robust numerical algorithm for the calculation of multiple-scattering angular distributions of high-energy electrons and positrons is described. This algorithm implements the multiple-scattering theories of Goudsmit-Saunderson, which disregards energy losses, and of Lewis, which accounts for energy losses within the continuous slowing down approximation. We have used partial-wave elastic scattering differential cross sections, generated with a recently developed program ELSEPA, in the calculations. The contribution of inelastic collisions to multiple-scattering angular distributions is treated in detail using inelastic scattering angular differential cross sections obtained from the Sternheimer-Liljequist generalised oscillator strength model. The stopping powers adopted in the calculations are consistent with the values recommended in the ICRU 37 report. The coefficients in the Legendre expansion of the single-scattering distribution are calculated by using the N-point Gauss-Legendre integration formula, coded in such a way that it allows the generation of a large number of expansion coefficients simultaneously. A computer program has been written to calculate angular multiple-scattering distributions for given path lengths, which can be readily adopted for class I Monte Carlo simulations.
The DtN nonreflecting boundary condition for multiple scattering problems in the half-plane
Acosta, Sebastian; Malone, Bruce
2013-01-01
The multiple-Dirichlet-to-Neumann (multiple-DtN) non-reflecting boundary condition is adapted to acoustic scattering from obstacles embedded in the half-plane. The multiple-DtN map is coupled with the method of images as an alternative model for multiple acoustic scattering in the presence of acoustically soft and hard plane boundaries. As opposed to the current practice of enclosing all obstacles with a large semicircular artificial boundary that contains portion of the plane boundary, the proposed technique uses small artificial circular boundaries that only enclose the immediate vicinity of each obstacle in the half-plane. The adapted multiple-DtN condition is simultaneously imposed in each of the artificial circular boundaries. As a result the computational effort is significantly reduced. A computationally advantageous boundary value problem is numerically solved with a finite difference method supported on boundary-fitted grids. Approximate solutions to problems involving two scatterers of arbitrary geo...
Shoukat, Sobia; Naqvi, Qaisar A.
2016-12-01
In this manuscript, scattering from a perfect electric conducting strip located at planar interface of topological insulator (TI)-chiral medium is investigated using the Kobayashi Potential method. Longitudinal components of electric and magnetic vector potential in terms of unknown weighting function are considered. Use of related set of boundary conditions yields two algebraic equations and four dual integral equations (DIEs). Integrand of two DIEs are expanded in terms of the characteristic functions with expansion coefficients which must satisfy, simultaneously, the discontinuous property of the Weber-Schafheitlin integrals, required edge and boundary conditions. The resulting expressions are then combined with algebraic equations to express the weighting function in terms of expansion coefficients, these expansion coefficients are then substituted in remaining DIEs. The projection is applied using the Jacobi polynomials. This treatment yields matrix equation for expansion coefficients which is solved numerically. These unknown expansion coefficients are used to find the scattered field. The far zone scattering width is investigated with respect to different parameters of the geometry, i.e, chirality of chiral medium, angle of incidence, size of the strip. Significant effects of different parameters including TI parameter on the scattering width are noted.
Multiple scattering of arbitrarily incident Bessel beams by random discrete particles.
Cui, Zhiwei; Han, Yiping; Ai, Xia
2013-11-01
In this paper, we introduce an efficient numerical method to characterize the multiple scattering by random discrete particles illuminated by Bessel beams with arbitrary incidence. Specifically, the vector expressions of Bessel beams that perfectly satisfy Maxwell's equations in combination with rotation Euler angles are used to represent the arbitrarily incident Bessel beams. A hybrid vector finite element-boundary integral-characteristic-basis function method is utilized to formulate the scattering problems involving multiple discrete particles with a random distribution. Due to the flexibility of the finite element method, the adopted method can conveniently deal with the problems of multiple scattering by randomly distributed homogeneous particles, inhomogeneous particles, and anisotropic particles. Some numerical results are included to illustrate the validity and capability of the proposed method and to show the scattering behaviors of random discrete particles when they are illuminated by Bessel beams.
Klenk, K F
1973-01-01
The changing slope of d sigma /dt at small mod t mod observed in the CERN-ISR p-p scattering data can be reproduced in the Glauber multiple quark scattering model by a quark-quark scattering amplitude that is an undamped rapidly oscillating function of momentum transferred to the quark. (9 refs).
Multiple Scattering Effects on Transmission through the Atmosphere.
1984-11-01
Office) 1S. SECURITY CLASS. (of tis report) Unclassified 15a. DECL ASSI FICATION/ DOWNGRADING SCHEDULE * d1l. DISTRIBUTION STATEMENT (of thise Repoit... Machado and Rubens A. Siglemann. 11. "Experiments on picosecond pulse propagation in a diffuse medium," Journal of the Optical Society of America, 73...34 * . "*1.o.6 4. Publications - continued Paper Presentations Related to the Contract Since September 1978 I ..- 25. J. Machado , R. A. Sigelmann, and A
Ground Vibration Isolation of Multiple Scattering by Using Rows of Tubular Piles as Barriers
Directory of Open Access Journals (Sweden)
Miao-miao Sun
2014-01-01
Full Text Available A new formal solution for the multiple scattering of plane harmonic waves by a group of arbitrary configuration tubular piles in an elastic total space is derived. Each order of scattering satisfies prescribed boundary conditions at the interface of tubular piles, which is delivered as the sum of incident and scattering waves. The first order performs the scattering wave by each scattered pile and the subsequent orders resulted from the excitation of each pile of first order of scattering from the remaining tubular piles. Advanced scattering orders can be regarded as the same manners. Several series of scattering coefficients are figured out with the aids of addition theorem so that the exact steady-state solution for the scattered displacement and stress is obtained. Particularly, when internal diameter of tubular piles tends to be infinitely small, it degenerates to a solid pile problem. By imposing the normalized displacement amplitudes and transmissibility indices, the influences of specific parameters such as scattering orders, internal and external diameter ratio of piles, pile material rigidity, position and distances between tubular pile and pile rows, and pile numbers are discussed. Certain recommended conclusions have been drawn as the guidelines of practical engineering design for discontinuous barrier of tubular piles.
Multiple gold-dimer detection from large scattering background
Hong, Xin; Jin, Zheng
2016-10-01
Gold nanoparticles exhibit unique plasmonic optical properties in visible to near infrared band. Especially the coupling effect existing at the gap between a closely linked particle pair can make the local field strongly enhanced. These properties make gold particles more attractive to be employed as molecular probes in biomedical related fundamental and clinical researches. However in the bio-system exist many large molecules or groups, whose optical signals can strongly depress the gold particles without detectable. In this paper, we proposed a method to extract the targets which are labelled by gold dimer pairs from large scattering background.
Scaling up Echo-State Networks with multiple light scattering
Dong, Jonathan; Krzakala, Florent; Wainrib, Gilles
2016-01-01
Echo-State Networks and Reservoir Computing have been studied for more than a decade. As they provide an elegant yet powerful alternative to traditional computing, researchers have tried to implement them using physical systems, in particular non-linear optical elements, achieving high bandwidth and low power consumption. Here we present a completely different optical implementation of Echo-State Networks using light-scattering materials. As a proof of concept, binary networks have been successfully trained to perform non-linear operations on time series and memory of such networks has been evaluated. This new method is fast, power efficient and easily scalable to very large networks.
Furumoto, T; Yamamoto, Y
2016-01-01
We investigate the property of the high-density nuclear matter probed by the nucleus-nucleus elastic scattering in the framework of the double-folding (DF) model with the complex $G$-matrix interaction. The medium effect including three-body-force (TBF) effect is investigated with present two methods based on the frozen density approximation. With the both methods, the medium effect in the high density region is clearly seen on the potential and the elastic cross section of the $^{16}$O + $^{16}$O system at $E/A =$ 70 MeV. The crucial role of the medium effect for the high-density nuclear matter is also confirmed with other effective nucleon-nucleon ($NN$) interactions. In addition, present methods are applied to other heavy-ion elastic scattering systems. Again, the medium effect in the high-density region is clearly seen in the heavy-ion elastic cross section. The effect on the elastic cross section becomes invisible with the increase of the target mass and the incident energy within existing the experiment...
Enhancing light transmission through a random medium with inhomogeneous scattering and loss
Sarma, Raktim; Cao, Hui
2016-01-01
We enhanced the total transmission of light through a disordered waveguide with spatially inhomogeneous scattering and loss by shaping the incident wavefront of a laser beam. Using an on-chip tapered lead, we were able to access all input modes in the waveguide with a spatial light modulator. The adaptive wavefront shaping resulted in selective coupling of input light to high transmission channels, which bypassed the regions of higher scattering and loss in the waveguide. The spatial inhomogeneity of scattering and loss led to redirecting of energy flux to optical paths with less scattering and loss to maximize total energy transported through the system. This work demonstrated the power of wavefront shaping in coherent control of light transport in inhomogeneous scattering media, which are common in real applications.
Dawidowski, J; Koza, M M; Blostein, J J; Aurelio, G; Fernández-Guillermet, A; Donato, P G
2002-01-01
We present a method of analysis of inelastic neutron scattering (INS) experiments aiming at obtaining the density of phonon states in an absolute scale, as well as a reliable value of the mean-square displacement of the atoms. This method requires the measurement of the neutron total cross section of the sample as a function of energy, which provides a normalization condition for the INS experiment, as well as a value of the mean-square displacement. The method is applied in the case of an incoherent neutron scattering system, viz. the Ti-52wt.% Zr alloy. The applicability of this method to the study of metal alloys and other systems is discussed.
Ranging in an underwater medium with multiple isogradient sound speed profile layers
Ramezani, H.; Leus, G.
2012-01-01
In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment. The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP) layers where in each layer the sound speed is linearly related to the depth. Furthermore, eac
Influence of Turbid Medium Parameters on Back Scattered Intensity and Pulsewidth of Picosecond Pulse
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
In this paper, we simulate a practical in vivo technique in which is produced influence of turbid medium parameters on backscattered intensity and pulsewidth of picosecond for turbid tissue surface of a semiinfinite medium by a small narrow linewidth laser beams. It is shown that the interaction of the ultra short pulse and the turbid tissue is very used as researching the optical parameters of the turbid medium.
Ultra-fast hybrid CPU-GPU multiple scatter simulation for 3-D PET.
Kim, Kyung Sang; Son, Young Don; Cho, Zang Hee; Ra, Jong Beom; Ye, Jong Chul
2014-01-01
Scatter correction is very important in 3-D PET reconstruction due to a large scatter contribution in measurements. Currently, one of the most popular methods is the so-called single scatter simulation (SSS), which considers single Compton scattering contributions from many randomly distributed scatter points. The SSS enables a fast calculation of scattering with a relatively high accuracy; however, the accuracy of SSS is dependent on the accuracy of tail fitting to find a correct scaling factor, which is often difficult in low photon count measurements. To overcome this drawback as well as to improve accuracy of scatter estimation by incorporating multiple scattering contribution, we propose a multiple scatter simulation (MSS) based on a simplified Monte Carlo (MC) simulation that considers photon migration and interactions due to photoelectric absorption and Compton scattering. Unlike the SSS, the MSS calculates a scaling factor by comparing simulated prompt data with the measured data in the whole volume, which enables a more robust estimation of a scaling factor. Even though the proposed MSS is based on MC, a significant acceleration of the computational time is possible by using a virtual detector array with a larger pitch by exploiting that the scatter distribution varies slowly in spatial domain. Furthermore, our MSS implementation is nicely fit to a parallel implementation using graphic processor unit (GPU). In particular, we exploit a hybrid CPU-GPU technique using the open multiprocessing and the compute unified device architecture, which results in 128.3 times faster than using a single CPU. Overall, the computational time of MSS is 9.4 s for a high-resolution research tomograph (HRRT) system. The performance of the proposed MSS is validated through actual experiments using an HRRT.
Energy Technology Data Exchange (ETDEWEB)
Yoshino, Hironori; Wada, Kenji; Horinaka, Hiromichi; Cho, Yoshio [Osaka Prefectural Univ., Sakai (Japan). Coll. of Engineering; Umeda, Tokuo; Osawa, Masahiko
1995-09-01
The Lambert-Beer law holding for pulsed lights transmitted through a scattering medium was examined using a streak camera. The Lambert-Beer law dynamic range is found to be limited by floor levels that are caused by scattered photons and are controllable by the use of a temporal gate on the transmitted pulse. The dynamic range improvement obtained for a scattering medium of 2.8 cm{sup -1} scattering coefficient of a thickness of 80 mm by a temporal gate of 60 ps was as much as 50 dB and the Lambert-Beer law dynamic rang reached to 140 dB. (author).
Multiple magnetic impurities on surfaces: Scattering and quasiparticle interference
Mitchell, A.
2015-01-01
We study systems of multiple interacting quantum impurities deposited on a metallic surface in a three-dimensional host. For the real-space two-impurity problem, using numerical renormalization group calculations, a rich range of behavior is shown to arise due to the interplay between Kondo physics
Conkey, Donald B; Caravaca-Aguirre, Antonio M; Piestun, Rafael
2012-01-16
We introduce a phase-control holographic technique to characterize scattering media with the purpose of focusing light through it. The system generates computer-generated holograms implemented via a deformable mirror device (DMD) based on micro-electro-mechanical technology. The DMD can be updated at high data rates, enabling high speed wavefront measurements using the transmission matrix method. The transmission matrix of a scattering material determines the hologram required for focusing through the scatterer. We demonstrate this technique measuring a transmission matrix with 256 input modes and a single output mode in 33.8 ms and creating a focus with a signal to background ratio of 160. We also demonstrate focusing through a temporally dynamic, strongly scattering sample with short speckle decorrelation times.
On the Theory and Simulation of Multiple Coulomb Scattering of Heavy Charged Particles
Striganov, S I
2004-01-01
The Moliere theory of multiple Coulomb scattering is modified to take into account difference between scattering off atomic nuclei and electron. A simple analytical expression for angular distribution of charged particles passing through a thick absorber is found. It does not assume any special form for a differential cross section and has wider range of applicability than a Gaussian approximation. A well-known method to simulate multiple Coulomb scattering is based on the different treatment of soft and hard collisions. An angular deflection in a large number of soft collisions is sampled using the proposed distribution function, a small number of hard collisions are simulated directly. A boundary between hard and soft collisions is defined providing a precise sampling of scattering angle (1% level) and small number of hard collisions. A corresponding simulation module takes into account projectile and nucleus charge distributions and exact kinematics of a projectile-electron interaction.
Frequency width of open channels in multiple scattering media.
Bosch, Jeroen; Goorden, Sebastianus A; Mosk, Allard P
2016-11-14
We report optical measurements of the spectral width of open transmission channels in a three-dimensional diffusive medium. The light transmission through a sample is enhanced by efficiently coupling to open transmission channels using repeated digital optical phase conjugation. The spectral properties are investigated by enhancing the transmission, fixing the incident wavefront and scanning the wavelength of the laser. We measure the transmitted field to extract the field correlation function and the enhancement of the total transmission. We find that optimizing the total transmission leads to a significant increase in the frequency width of the field correlation function. Additionally we find that the enhanced transmission persists over an even larger frequency bandwidth. This result shows open channels in the diffusive regime are spectrally much wider than previous measurements in the localized regime suggest.
Pathlengths of open channels in multiple scattering media
Bosch, Jeroen; Mosk, Allard P
2016-01-01
We report optical measurements of the spectral width of open transmission channels in a three-dimensional diffusive medium. The light transmission through a sample is enhanced by efficiently coupling to open transmission channels using repeated digital optical phase conjugation. The spectral properties are investigated by enhancing the transmission, fixing the incident wavefront and scanning the wavelength of the laser. We measure the transmitted field to extract the field correlation function and the enhancement of the total transmission. We find that optimizing the total transmission leads to a significant increase in the frequency width of the field correlation function. Additionally we find that the enhanced transmission persists over an even larger frequency bandwidth. This result shows open channels in the diffusive regime are spectrally much wider than previous measurements in the localized regime suggest.
Effects of multiple scattering on light pulses reflected by turbid atmospheres
Weinman, J. A.
1976-01-01
Multiple scattering contributions to lidar returns from turbid atmospheres are derived by means of an analytical theory. It is assumed that scattering takes place mainly at small angles except for one event that scatters the light backward. The phase functions are approximated by the sum of Gaussian functions of the scattering angle in both the forward and backward directions. The three-dimensional radiative transfer equation is transformed to a one-dimensional problem by means of Fourier transforms. Neumann solutions to the transformed equation of radiative transfer are then found. A number of examples are presented for cloud, fog and haze models. The results are found to be in satisfactory agreement with results obtained from the Monte Carlo analysis of Kunkel (1974) and the theory of light pulses doubly scattered by turbid atmospheres which was developed by Eloranta (1972).
Mandour, M A; Harder, D
1978-08-01
The algorithn proposed in 1976 to allow for the influences of tissue inhomogeneities in electron beam dose distributions has been improved. A factor adopted from Sternheimer corrects for differences in lateral displacement by multiple scattering within the inhomogeneity resp. the equivalent layer of the homogeneous medium. The algorithm has been tested by direct comparison with Monte Carlo computations for the example of cylindrical cavities in carbon at Eo=10 MeV and resulted in a very close approximation.
Application of Multiple Scattering Theory to Lower Energy Elastic Nucleon-Nucleus Reactions
Chinn, C. R.; Elster, Ch.; Thaler, R. M.; Weppner, S. P.
1994-01-01
The optical model potentials for nucleon-nucleus elastic scattering at $65$~MeV are calculated for $^{12}$C, $^{16}$O, $^{28}$Si, $^{40}$Ca, $^{56}$Fe, $^{90}$Zr and $^{208}$Pb in first order multiple scattering theory, following the prescription of the spectator expansion, where the only inputs are the free NN potentials, the nuclear densities and the nuclear mean field as derived from microscopic nuclear structure calculations. These potentials are used to predict differential cross section...
Multiple Scattering Expansion of the Self-Energy at Finite Temperature
Jeon, S; Jeon, Sangyong; Ellis, Paul J.
1998-01-01
An often used rule that the thermal correction to the self-energy is the thermal phase-space times the forward scattering amplitude from target particles is shown to be the leading term in an exact multiple scattering expansion. Starting from imaginary-time finite-temperature field theory, a rigorous expansion for the retarded self-energy is derived. The relationship to the thermodynamic potential is briefly discussed.
Liu, Xiaodong
2017-08-01
A sampling method by using scattering amplitude is proposed for shape and location reconstruction in inverse acoustic scattering problems. Only matrix multiplication is involved in the computation, thus the novel sampling method is very easy and simple to implement. With the help of the factorization of the far field operator, we establish an inf-criterion for characterization of underlying scatterers. This result is then used to give a lower bound of the proposed indicator functional for sampling points inside the scatterers. While for the sampling points outside the scatterers, we show that the indicator functional decays like the bessel functions as the sampling point goes away from the boundary of the scatterers. We also show that the proposed indicator functional continuously depends on the scattering amplitude, this further implies that the novel sampling method is extremely stable with respect to errors in the data. Different to the classical sampling method such as the linear sampling method or the factorization method, from the numerical point of view, the novel indicator takes its maximum near the boundary of the underlying target and decays like the bessel functions as the sampling points go away from the boundary. The numerical simulations also show that the proposed sampling method can deal with multiple multiscale case, even the different components are close to each other.
Improved separation of soft and hard components in multiple Coulomb scattering
Bondarenco, M V
2016-01-01
Evaluation of the angular distribution function of particles scattered in an amorphous medium is improved by deforming the integration path in the Fourier integral representation into the complex plane. That allows us to present the distribution function as a sum of two positive components, soft and hard, the soft component being close to a Gaussian, and the hard component vanishing in the forward direction, while including the Rutherford asymptotics and all the power corrections to it at large scattering angles. Detailed properties of those components, and their interplay at intermediate deflection angles are discussed. Comparison with the Moli\\`{e}re theory is given.
Supersymmetric and Kaluza-Klein Particles Multiple Scattering in the Earth
Energy Technology Data Exchange (ETDEWEB)
Albuquerque, Ivone; Klein, Spencer
2009-05-19
Neutrino telescopes with cubic kilometer volume have the potential to discover new particles. Among them are next to lightest supersymmetric (NLSPs) and next to lightest Kaluza-Klein (NLKPs) particles. Two NLSPs or NLKPs will transverse the detector simultaneously producing parallel charged tracks. The track separation inside the detector can be a few hundred meters. As these particles might propagate a few thousand kilometers before reaching the detector, multiple scattering could enhance the pair separation at the detector. We find that the multiple scattering will alter the separation distribution enough to increase the number of NLKP pairs separated by more than 100 meters (a reasonable experimental cut) by up to 46% depending on the NLKP mass. Vertical upcoming NLSPs will have their separation increased by 24% due to multiple scattering.
Multiple Scattering and Visco-Thermal Effects on 2D Phononic Crystal
Duclos, Aroune; Pagneux, Vincent
2008-01-01
In this paper, we are interested in the transition between regimes here either visco-thermal or multiple scattering effects dominate for the propagation of acoustic waves through a 2D regular square array of rigid cylinders embedded in air. An extension of the numerical method using Schl\\"omilch series is performed in order to account for visco-thermal losses. Comparison withexperimental data and results from classical homogenization theory allows to study the transition between a low frequency limit (where viscous and thermal effects dominate) and a high frequency regime (where multiple scattering effects become predominant). For this particular geometry, a large frequency domain where visco-thermal and multiple scattering effects coexist is found.
Directory of Open Access Journals (Sweden)
Daqing Piao
2014-12-01
Full Text Available Recent focused Monte Carlo and experimental studies on steady-state single-fiber reflectance spectroscopy (SfRS from a biologically relevant scattering medium have revealed that, as the dimensionless reduced scattering of the medium increases, the SfRS intensity increases monotonically until reaching a plateau. The SfRS signal is semi-empirically decomposed to the product of three contributing factors, including a ratio-of-remission (RoR term that refers to the ratio of photons remitting from the medium and crossing the fiber-medium interface over the total number of photons launched into the medium. The RoR is expressed with respect to the dimensionless reduced scattering parameter , where is the reduced scattering coefficient of the medium and is the diameter of the probing fiber. We develop in this work, under the assumption of an isotropic-scattering medium, a method of analytical treatment that will indicate the pattern of RoR as a function of the dimensionless reduced scattering of the medium. The RoR is derived in four cases, corresponding to in-medium (applied to interstitial probing of biological tissue or surface-based (applied to contact-probing of biological tissue SfRS measurements using straight-polished or angle-polished fiber. The analytically arrived surface-probing RoR corresponding to single-fiber probing using a 15° angle-polished fiber over the range of agrees with previously reported similarly configured experimental measurement from a scattering medium that has a Henyey–Greenstein scattering phase function with an anisotropy factor of 0.8. In cases of a medium scattering light anisotropically, we propose how the treatment may be furthered to account for the scattering anisotropy using the result of a study of light scattering close to the point-of-entry by Vitkin et al. (Nat. Commun. 2011, doi:10.1038/ncomms1599.
Directory of Open Access Journals (Sweden)
Jungki Lee
2015-01-01
Full Text Available The parallel volume integral equation method (PVIEM is applied for the analysis of elastic wave scattering problems in an unbounded isotropic solid containing multiple multilayered anisotropic elliptical inclusions. This recently developed numerical method does not require the use of Green’s function for the multilayered anisotropic inclusions; only Green’s function for the unbounded isotropic matrix is needed. This method can also be applied to solve general two- and three-dimensional elastodynamic problems involving inhomogeneous and/or multilayered anisotropic inclusions whose shape and number are arbitrary. A detailed analysis of the SH wave scattering is presented for multiple triple-layered orthotropic elliptical inclusions. Numerical results are presented for the displacement fields at the interfaces for square and hexagonal packing arrays of triple-layered elliptical inclusions in a broad frequency range of practical interest. It is necessary to use standard parallel programming, such as MPI (message passing interface, to speed up computation in the volume integral equation method (VIEM. Parallel volume integral equation method as a pioneer of numerical analysis enables us to investigate the effects of single/multiple scattering, fiber packing type, fiber volume fraction, single/multiple layer(s, multilayer’s shape and geometry, isotropy/anisotropy, and softness/hardness of the multiple multilayered anisotropic elliptical inclusions on displacements at the interfaces of the inclusions.
Fiorino, Steven T.; Elmore, Brannon; Schmidt, Jaclyn; Matchefts, Elizabeth; Burley, Jarred L.
2016-05-01
Properly accounting for multiple scattering effects can have important implications for remote sensing and possibly directed energy applications. For example, increasing path radiance can affect signal noise. This study describes the implementation of a fast-calculating two-stream-like multiple scattering algorithm that captures azimuthal and elevation variations into the Laser Environmental Effects Definition and Reference (LEEDR) atmospheric characterization and radiative transfer code. The multiple scattering algorithm fully solves for molecular, aerosol, cloud, and precipitation single-scatter layer effects with a Mie algorithm at every calculation point/layer rather than an interpolated value from a pre-calculated look-up-table. This top-down cumulative diffusivity method first considers the incident solar radiance contribution to a given layer accounting for solid angle and elevation, and it then measures the contribution of diffused energy from previous layers based on the transmission of the current level to produce a cumulative radiance that is reflected from a surface and measured at the aperture at the observer. Then a unique set of asymmetry and backscattering phase function parameter calculations are made which account for the radiance loss due to the molecular and aerosol constituent reflectivity within a level and allows for a more accurate characterization of diffuse layers that contribute to multiple scattered radiances in inhomogeneous atmospheres. The code logic is valid for spectral bands between 200 nm and radio wavelengths, and the accuracy is demonstrated by comparing the results from LEEDR to observed sky radiance data.
Loc, Bui Minh; Zegers, R G T
2014-01-01
The charge-exchange (3He,t) scattering to the isobaric analog state (IAS) of the target can be considered as "elastic" scattering of 3He by the isovector term of the optical potential (OP) that flips the projectile isospin. Therefore, the accurately measured charge-exchange scattering cross- section for the IAS can be a good probe of the isospin dependence of the OP, which is determined exclusively within the folding model by the difference between the neutron and proton densities and isospin dependence of the nucleon-nucleon interaction. Given the neutron skin of the target is related directly to the same density difference, it can be well probed in the analysis of the charge- exchange (3He,t) reactions at medium energies when the two-step processes can be neglected and the t-matrix interaction can be used in the folding calculation. For this purpose, the data of the (3He,t) scattering to the IAS of 90Zr and 208Pb targets at Elab = 420 MeV have been analyzed in the distorted wave Born approximation using the...
Modeling of laser light scattering in a medium with spherical particles
Larionova, Nadezhda L.; Maksimova, Irina L.
2001-05-01
Laser light radiation scattered by the system of spheres with various parameters was theoretically investigated by using of the Mie theory of electromagnetic scattering by a single sphere. The calculations were performed for systems of particles whose coordinates were specifically realized in random fashion according to the specified probabilities defined by the approximation of hard spheres. The parameters of model are the same as in the eye lense biotissue and were carried out by using of medical data about internal structure of men lens and some animals. In general the studied model presents the system of homogeneous spherical particles which are randomly distributed in the layer of thickness. We study the optical properties such as scattering effective cross-section and function of correlation in different models.
Single-shot optical imaging through scattering medium using digital in-line holography
R., Vinu; Somkuwar, Atul S; Park, YongKeun; Singh, Rakesh Kumar
2016-01-01
Non-invasive and single-shot holographic imaging through complex media is technically challenging due to random light scattering which significantly scrambles optical information. Recently, several methods have been presented to address this issue. However, they require complicated measurements of optical transmission matrices, or existing techniques do only retrieve intensity information. Here we propose and experimentally demonstrate a holographic approach for single-shot imaging through a scattering layer based on digital in-line holography in combination with the autocorrelation of the speckle intensity. Using a simple optical configuration and experimental procedure, the proposed method enables to retrieve the complex amplitude image of an object located at arbitrary planes behind scattering media. The technique has potential applications in biomedical imaging, deep tissue microscopy, and 3D imaging through turbid media.
Padhy, S.
2010-12-01
We investigated the intrinsic dissipation and scattering properties of the lithosphere beneath the northeast India by using the seismic waves recorded by a network of ten broadband stations in the region with hypocentral distances ranging from 31 to 200 km. First, we determined coda Q from the amplitude decay rate of the S-wave coda envelopes in five frequency bands from 1.5 to 24 Hz based on single scattering theory and QS by means of the coda normalization method. Assuming a frequency dependent power-law of the form , we found a low Q0 (Q0 India is seismically active and heterogeneous. Then we applied the multiple lapse time window (MLTW) analysis in the hypothesis of velocity and scattering coefficients constant with depth. We calculated the variation of integrated spectral energy with hypocentral distance for three consecutive lapse time windows (0-15, 15-30, 30-45 sec), starting from the onset of the S-wave arrival. The spectral energies over an octave bandwidth with central frequencies at 1.5, 3, 6, 12 and 24 Hz were calculated to obtain the frequency dependence of attenuation parameters. The results show that intrinsic absorption dominates over scattering in the attenuation process at high frequencies. However, in the hypothesis of uniform medium, the estimates of scattering attenuations obtained by MLTW analysis are overestimated. So the present results are correct to a first order approximation. To obtain more reliable and unbiased estimates of the attenuation parameters and their frequency dependences by considering the probable influence of crustal-mantel heterogeneities, we analyze the events by using the depth dependent MLTW method.
Masson, Yder; Romanowicz, Barbara
2016-11-01
We derive a fast discrete solution to the scattering problem. This solution allows us to compute accurate synthetic seismograms or waveforms for arbitrary locations of sources and receivers within a medium containing localized perturbations. The key to efficiency is that wave propagation modeling does not need to be carried out in the entire volume that encompasses the sources and the receivers but only within the sub-volume containing the perturbations or scatterers. The proposed solution has important applications, for example, it permits the imaging of remote targets located in regions where no sources or receivers are present. Our solution relies on domain decomposition: within a small volume that contains the scatterers, wave propagation is modeled numerically, while in the surrounding volume, where the medium isn't perturbed, the response is obtained through wavefield extrapolation. The originality of this work is the derivation of discrete formulas for representation theorems and Kirchhoff-Helmholtz integrals that naturally adapt to the numerical scheme employed for modeling wave propagation. Our solution applies, for example, to finite difference methods or finite/spectral elements methods. The synthetic seismograms obtained with our solution can be considered "exact" as the total numerical error is comparable to that of the method employed for modeling wave propagation. We detail a basic implementation of our solution in the acoustic case using the finite difference method and present numerical examples that demonstrate the accuracy of the method. We show that ignoring some terms accounting for higher order scattering effects in our solution has a limited effect on the computed seismograms and significantly reduces the computational effort. Finally, we show that our solution can be used to compute localised sensitivity kernels and we discuss applications to target oriented imaging. Extension to the elastic case is straightforward and summarised in a
Resonant Rayleigh scattering of exciton-polaritons in multiple quantum wells
DEFF Research Database (Denmark)
Malpuech, Guillaume; Kavokin, Alexey; Langbein, Wolfgang Werner;
2000-01-01
A theoretical concept of resonant Rayleigh scattering (RRS) of exciton-polaritons in multiple quantum wells (QWs) is presented. The optical coupling between excitons in different QWs can strongly affect the RRS dynamics, giving rise to characteristic temporal oscillations on a picosecond scale....... Bragg and anti-Bragg arranged QW structures with the same excitonic parameters are predicted to have drastically different RRS spectra. Experimental data on the RRS from multiple QWs show the predicted strong temporal oscillations at small scattering angles, which are well explained by the presented...
Energy loss of protons in SrTiO{sub 3} studied by medium energy ion scattering
Energy Technology Data Exchange (ETDEWEB)
Dedyulin, S.N., E-mail: sdedyuli@uwo.ca [Department of Physics and Astronomy, Western University, London, Ontario, N6A 3K7 (Canada); Singh, M.P.; Razavi, F.S. [Department of Physics, Brock University, St. Catherines, Ontario, L2S 3A1 (Canada); Goncharova, L.V. [Department of Physics and Astronomy, Western University, London, Ontario, N6A 3K7 (Canada)
2012-10-01
The energy loss of medium energy protons (55-170 keV/amu) was studied for a thin SrTiO{sub 3} film on Si. The thickness of the film and the structure of the SrTiO{sub 3}/Si interface was determined by the combination of X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS) and medium energy ion scattering (MEIS). These film parameters, together with energy losses extracted from MEIS spectra, were used to calculate stopping cross sections of SrTiO{sub 3} by an iterative procedure. In comparison with Andersen and Ziegler values, the data are systematically lower over the whole energy range.
Remizovich, V. S.
2010-06-01
It is commonly accepted that the Schwarzschild-Schuster two-flux approximation (1905, 1914) can be employed only for the calculation of the energy characteristics of the radiation field (energy density and energy flux density) and cannot be used to characterize the angular distribution of radiation field. However, such an inference is not valid. In several cases, one can calculate the radiation intensity inside matter and the reflected radiation with the aid of this simplest approximation in the transport theory. In this work, we use the results of the simplest one-parameter variant of the two-flux approximation to calculate the angular distribution (reflection function) of the radiation reflected by a semi-infinite isotropically scattering dissipative medium when a relatively broad beam is incident on the medium at an arbitrary angle relative to the surface. We do not employ the invariance principle and demonstrate that the reflection function exhibits the multiplicative property. It can be represented as a product of three functions: the reflection function corresponding to the single scattering and two identical h functions, which have the same physical meaning as the Ambartsumyan-Chandrasekhar function ( H) has. This circumstance allows a relatively easy derivation of simple analytical expressions for the H function, total reflectance, and reflection function. We can easily determine the relative contribution of the true single scattering in the photon backscattering at an arbitrary probability of photon survival Λ. We compare all of the parameters of the backscattered radiation with the data resulting from the calculations using the exact theory of Ambartsumyan, Chandrasekhar, et al., which was developed decades after the two-flux approximation. Thus, we avoid the application of fine mathematical methods (the Wiener-Hopf method, the Case method of singular functions, etc.) and obtain simple analytical expressions for the parameters of the scattered radiation
Fast and scalable algorithm for the simulation of multiple Mie scattering in optical systems.
Kalthoff, Oliver; Kampmann, Ronald; Streicher, Simon; Sinzinger, Stefan
2016-05-20
The Monte Carlo simulation of light propagation in optical systems requires the processing of a large number of photons to achieve a satisfactory statistical accuracy. Based on classical Mie scattering, we experimentally show that the independence of photons propagating through a turbid medium imposes a postulate for a concurrent and scalable programming paradigm of general purpose graphics processing units. This ensures that, without rewriting code, increasingly complex optical systems can be simulated if more processors are available in the future.
Multiple scattering dynamics of fermions at an isolated p-wave resonance
Thomas, R.; Roberts, K. O.; Tiesinga, E.; Wade, A. C. J.; Blakie, P. B.; Deb, A. B.; Kjærgaard, N.
2016-07-01
The wavefunction for indistinguishable fermions is anti-symmetric under particle exchange, which directly leads to the Pauli exclusion principle, and hence underlies the structure of atoms and the properties of almost all materials. In the dynamics of collisions between two indistinguishable fermions, this requirement strictly prohibits scattering into 90° angles. Here we experimentally investigate the collisions of ultracold clouds fermionic 40K atoms by directly measuring scattering distributions. With increasing collision energy we identify the Wigner threshold for p-wave scattering with its tell-tale dumb-bell shape and no 90° yield. Above this threshold, effects of multiple scattering become manifest as deviations from the underlying binary p-wave shape, adding particles either isotropically or axially. A shape resonance for 40K facilitates the separate observation of these two processes. The isotropically enhanced multiple scattering mode is a generic p-wave threshold phenomenon, whereas the axially enhanced mode should occur in any colliding particle system with an elastic scattering resonance.
Scattering of SH-wave by multiple circular cavities in half space
Institute of Scientific and Technical Information of China (English)
王国庆; 刘殿魁
2002-01-01
In this paper, an analytic method is developed to address steady SH-wave scattering and perform dynamic analysisof multiple circular cavities in half space. The scattered wave function used for scattering of SH-waves by multiple circularcavities, which automatically satisfies the stress-free condition at the horizontal surface, is constructed by applying thesymmetry of the SH-wave scattering and the method of multi-polar coordinates system. Applying this scattered wave functionand method of moving coordinates, the original problem can be transformed to the problem of SH-wave scattering by multiplecircular cavities in the full space. Finally, the solution of the problem can be reduced to a series of algebraic equations andsolved numerically by truncating the infinite algebraic equations to the finite ones. Numerical examples are provided for casewith two cavities to show the effect of wave number, and the distances between the centers of the cavities and from the centersto the ground surface on the dynamic stress concentration around the cavity impacted by incident steady SH-wave.
PSTD Simulations of Multiple Light Scattering in 3-D Macrocsopic Random Media
Energy Technology Data Exchange (ETDEWEB)
Tseng, S H; Taflove, A; Maitland, D; Backman, V
2005-10-19
We report a full-vector, three-dimensional, numerical solution of Maxwell's equations for optical propagation within, and scattering by, a random medium of macroscopic dimensions. The total scattering cross-section is determined using the pseudospectral time-domain technique. Specific results reported in this Paper indicate that multiply scattered light also contains information that can be extracted by the proposed cross-correlation analysis. On a broader perspective, our results demonstrate the feasibility of accurately determining the optical characteristics of arbitrary, macroscopic random media, including geometries with continuous variations of refractive index. Specifically, our results point toward the new possibilities of tissue optics--by numerically solving Maxwell's equations, the optical properties of tissue structures can be determined unambiguously.
Parnell, William J.; Abrahams, I. David
2010-11-01
In this article we attempt to clarify various notions regarding multiple point scattering. We consider several predictions for the effective material properties of an inhomogeneous slab region which can be derived from classical multiple scattering theories. In particular we are interested in the point scattering limit when wavelengths λ0 ≫ l ∼ a where l is the characteristic length-scale of the distance between inclusions and a is the characteristic length-scale of inclusions. In this limit we are able to derive effective properties which are physically valid for any volume fraction φ, except in the sound-soft scatterer case where there is a condition on the size of φ. We shall confine attention to random distributions of inclusions and employ the Quasi-Crystalline Approximation to yield results. In particular we discuss the different scenarios of acoustics and antiplane elasticity and stress the reciprocity between these two problems which means that they can be solved simultaneously. We make various statements regarding the efficacy of the various multiple scattering theories in the prediction of effective material properties in the quasi-static limit.
Scattering at oblique incidence by multiple cylinders in front of a surface
Lee, Siu-Chun
2016-10-01
This paper presents a theoretical solution for scattering by multiple parallel infinite cylinders located on top of a dielectric substrate. The incident plane wave is arbitrarily polarized and propagates in a general direction inclined from the axis of the cylinders. The scattered waves become depolarized at oblique incidence, which are reflected from the surface of the substrate to become incident waves at the cylinders. An exact solution of Maxwell's equations is developed that rigorously treats the depolarization of scattered waves and the angular spectrum of reflected and transmitted waves from the surface. Numerical results are presented for different configurations of perfectly conducting and coated cylinders at perpendicular and oblique incidence to illustrate plasmonic resonances in the near-field and scattering characteristics in the far-field.
Simulation of multiple scattering of seismic waves by spatially distributed inclusions
Institute of Scientific and Technical Information of China (English)
刘恩儒; QUEEN; John; H; 张中杰; 陈东
2000-01-01
A 2D elastodynamic boundary element method (BEM) is used to solve multiple scattering of elastic waves. The method is based on the integral representation of an elastic wave-field by assuming a fictitious source distribution on the scattering objects or inclusions, i.e. a mathematical description of Huygens’ principle, and the fictitious source distribution can be found by matching appropriate boundary conditions at the boundary of the inclusions. Numerical studies show that in the presence of cracks, spatial and scale-length distributions are important and different spatial arrangements of the same scatters lead to profound differences in scattering characteristics, in particular the frequency contents of the transmitted wave-fields. The frequency characteristics, such as the frequency of peak attenuation , can be related to spatial size parameters of the model.
Simulation of multiple scattering of seismic waves by spatially distributed inclusions
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
A 2D elastodynamic boundary element method (BEM) is used to solve multiple scattering of elastic waves. The method is based on the integral representation of an elastic wave-field by assuming a fictitious source distribution on the scattering objects or inclusions, i.e. a mathematical description of Huygens' principle, and the fictitious source distribution can be found by matching appropriate boundary conditions at the boundary of the inclusions. Numerical studies show that in the presence of cracks, spatial and scale-length distributions are important and different spatial arrangements of the same scatters lead to profound differences in scattering characteristics, in particular the frequency contents of the transmitted wave-fields. The frequency characteristics, such as the frequency of peak attenuation, can be related to spatial size parameters of the model.
ON SOURCE ANALYSIS BY WAVE SPLITTING WITH APPLICATIONS IN INVERSE SCATTERING OF MULTIPLE OBSTACLES
Institute of Scientific and Technical Information of China (English)
Fahmi ben Hassen; Jijun Liu; Roland Potthast
2007-01-01
We study wave splitting procedures for acoustic or electromagnetic scattering problems. The idea of these procedures is to split some scattered field into a sum of fields coming from different spatial regions such that this information can be used either for inversion algorithms or for active noise control. Splitting algorithms can be based on general boundary layer potential representation or Green's representation formula. We will prove the unique decomposition of scattered wave outside the specified reference domain G and the unique decomposition of far-field pattern with respect to different reference domain G. Further, we employ the splitting technique for field reconstruction for a scatterer with two or more separate components, by combining it with the point source method for wave recovery. Using the decomposition of scattered wave as well as its far-field pattern, the wave splitting procedure proposed in this paper gives an efficient way to the computation of scattered wave near the obstacle, from which the multiple obstacles which cause the far-field pattern can be reconstructed separately. This considerably extends the range of the decomposition methods in the area of inverse scattering. Finally, we will provide numerical examples to demonstrate the feasibility of the splitting method.
Group-fitted ab initiosingle- and multiple-scattering EXAFS Debye-Waller factors
Dimakis, Nicholas; Bunker, Grant
2002-05-01
X-ray absorption fine structure (XAFS) spectroscopy is one of the few direct probes of the structure of metalloprotein binding that is equally applicable to proteins in crystals, solutions, and membranes. Despite considerable progress in the calculation of the photoelectron scattering aspects of XAFS, calculation of the vibrational aspects has lagged because of the difficulty of the calculations. We report here initial results that express single- and multiple-scattering Debye-Waller factors as polynomial functions of first shell radial distance for metal-peptide complexes, enabling quantitatively accurate full multiple-scattering XAFS data analysis of active sites of unknown structure at arbitrary temperatures without the use of ad hoc assumptions.
POMME: A medium energy deuteron polarimeter based on semi-inclusive d-carbon scattering
Energy Technology Data Exchange (ETDEWEB)
Bonin, B.; Boudard, A.; Fanet, H.; Fergerson, R.W.; Garcon, M.; Giorgetti, C.; Habault, J.; Le Meur, J.; Lombard, R.M.; Lugol, J.C.; Mayer, B.; Mouly, J.P.; Tomasi-Gustafsson, E. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Service de Physique Nucleaire a Moyenne Energie); Duchazeaubeneix, J.C.; Yonnet, J. (Laboratoire National Saturne, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)); Morlet, M.; Wiele, J. van de; Willis, A. (Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire); Greeniaus, G. (Alberta Univ., Edmonton (Canada). Dept. of Physics British Columbia Univ., Vancouver (Canada). TRIUMF Facility); Gaillard, G. (Geneva Univ. (Switzerland). Inst. de Physique); Markowitz, P.; Perdrisat, C.F. (College of William and Mary, Williamsburg, VA (USA). Dept. of Physics); Abegg, R.; Hutcheon, D.A. (British Columbia Univ., Vancouver (Canada). TRIUMF Facility)
1990-03-15
POMME is the first calibrated deuteron polarimeter using a d + carbon semi-inclusive scattering reaction. We present the results of its calibration in the region T{sub d}=150-700 MeV, with the polarized deuteron beam from the synchrotron Saturne. A parametrization of the measured analyzing powers, and a discussion of the obtained efficiency and figure of merit are also given. (orig.).
Total neutron scattering: The key to the local and medium range structure of complex materials
Indian Academy of Sciences (India)
Th Proffen
2008-10-01
Structural characterization is mainly based on the measurement of Bragg intensities and yields the average structure of crystalline materials. The total scattering pattern, however, contains structural information over all length scales, and it can be used to obtain a complete structural picture of complex materials. Suddenly one has access to a new parameter, the real-space range of the refinement and structures can be analysed as a function of length scale straightforwardly.
Solution of a multiple-scattering inverse problem: electron diffraction from surfaces.
Saldin, D K; Seubert, A; Heinz, K
2002-03-18
We present a solution to the multiple-scattering inverse problem for low-energy electron diffraction that enables the determination of the three-dimensional atomic structure of an entire surface unit cell directly from measured data. The solution requires a knowledge of the structure of the underlying bulk crystal and is implemented by a maximum entropy algorithm.
Milton, Kimball A; Wagner, Jef; Cavero-Pelaez, Ines
2009-01-01
Various applications of the multiple scattering technique to calculating Casimir energy are described. These include the interaction between dilute bodies of various sizes and shapes, temperature dependence, interactions with multilayered and corrugated bodies, and new examples of exactly solvable separable bodies.
Multiple scattering in electron fluid and energy loss in multi-ionic targets
Energy Technology Data Exchange (ETDEWEB)
Deutsch, C., E-mail: claude.deutsch@u-psud.fr [LPGP, UParis-Sud, 91405-Orsay (France); Tahir, N.A. [GSI, 1Planck Str., 64291-Darmstadt (Germany); Barriga-Carrasco, M. [ETSII, UCastilla-la-Mancha, 13071 Ciudad-Real (Spain); Ceban, V. [LPGP, UParis-Sud, 91405-Orsay (France); Fromy, P. [CRI, UParis-Sud, 91405-Orsay (France); Gilles, D. [CEA/Saclay/DSM/IRFU/SAP, 91191-Gif-s-Yvette (France); Leger, D. [Laboratoire Monthouy, UValenciennes-Hainaut Cambresis (France); Maynard, G. [LPGP, UParis-Sud, 91405-Orsay (France); Tashev, B. [Department of Physics, KazNu, Tole Bi82, Almaty (Kazakhstan); Volpe, L. [Department of Physics, UMilano-Bicocca, Milano 20126 (Italy)
2014-01-01
Extensions of the standard stopping model (SSM) for ion projectiles interacting with dense targets of timely concern for ICF and WDM are reviewed. They include multiple scattering on partially degenerate electrons, low velocity ion slowing down in demixing H–He mixtures within Jovian planets core or multiionic target such as Kapton.
A Path Loss Model for Non-Line-of-Sight Ultraviolet Multiple Scattering Channels
2010-01-01
relevant model parameters. 2.3. Elementary Events for Photon RandomMigration. Gener- ally, it is impossible to predict with certainty the trajectory of a...Witt, “Multiple scattering in reflection nebulae—I: a Monte Carlo approach,” The Astrophysical Journal Supplement Series, vol. 35, pp. 1–6, 1977. [22] D
Coulomb Correction to the Screening Angle of the Moliere Multiple Scattering Theory
Kuraev, E A; Tarasov, A V
2012-01-01
Coulomb correction to the screening angular parameter of the Moliere multiple scattering theory is found. Numerical calculations are presented in the range of nuclear charge from Z=4 to Z=82. Comparison with the approximate Moliere result for the screening angle reveals up to 30% deviation from it for sufficiently heavy elements of the target material.
Neutrino energy estimates from multiple Coulomb scattering of upthroughgoing muons in MACRO
Bakari, D; Giorgini, M; Spurio, M
2002-01-01
Summary form only given. Estimates of the energies of neutrino induced muons in MACRO were made by measuring the multiple Coulomb scattering (MCS) in the rock absorbers in the lower part of the MACRO detector. The deflections of muons inside the detector depend on the muon energy. (1 refs).
Multiple scattering and accidental coincidences in the J-PET detector simulated using GATE package
Kowalski, P; Wiślicki, W; Raczyński, L; Bednarski, T; Białas, P; Bułka, J; Czerwiński, E; Gajos, A; Gruntowski, A; Kamińska, D; Kapłon, Ł; Kochanowski, A; Korcyl, G; Kowal, J; Kozik, T; Krzemień, W; Kubicz, E; Niedźwiecki, Sz; Pałka, M; Rudy, Z; Salabura, P; Sharma, N G; Silarski, M; Słomski, A; Smyrski, J; Strzelecki, A; Wieczorek, A; Wochlik, I; Zieliński, M; Zoń, N
2015-01-01
Novel Positron Emission Tomography system, based on plastic scintillators, is developed by the J-PET collaboration. In order to optimize geometrical configuration of built device, advanced computer simulations are performed. Detailed study is presented of background given by accidental coincidences and multiple scattering of gamma quanta.
Analysis of Spent Nuclear Fuel Imaging Using Multiple Coulomb Scattering of Cosmic Muons
Chatzidakis, Stylianos; Choi, Chan K.; Tsoukalas, Lefteri H.
2016-12-01
Cosmic ray muons passing through matter lose energy from inelastic collisions with electrons and are deflected from nuclei due to multiple Coulomb scattering. The strong dependence of scattering on atomic number Z and the recent developments on position sensitive muon detectors indicate that multiple Coulomb scattering could be an excellent candidate for spent nuclear fuel imaging. Muons present significant advantages over existing monitoring and imaging techniques and can play a central role in monitoring nuclear waste and spent nuclear fuel stored in dense well shielded containers. The main purpose of this paper is to investigate the applicability of multiple Coulomb scattering for imaging of spent nuclear fuel dry casks stored within vertical and horizontal commercial storage dry casks. Calculations of muon scattering were performed for various scenarios, including vertical and horizontal fully loaded dry casks, half loaded dry casks, dry casks with one row of fuel assemblies missing, dry casks with one fuel assembly missing and empty dry casks. Various detector sizes (1.2 m ×1.2 m, 2.4 m ×2.4 m and 3.6 m ×3.6 m) and number of muons (105, 5 · 105, 106 and 107) were used to assess the effect on image resolution. The Point-of-Closest-Approach (PoCA) algorithm was used for the reconstruction of the stored contents. The results demonstrate that multiple Coulomb scattering can be used to successfully reconstruct the dry cask contents and allow identification of all scenarios with the exception of one fuel assembly missing. In this case, an indication exists that a fuel assembly is not present; however, the resolution of the imaging algorithm was not enough to identify exact location.
Okamoto, Hajime; Sato, Kaori; Nishizawa, Tomoaki; Sugimoto, Nobuo; Makino, Toshiyuki; Jin, Yoshitaka; Shimizu, Atsushi; Takano, Toshiaki; Fujikawa, Masahiro
2016-12-26
We developed a multiple-field-of-view multiple-scattering polarization lidar (MFMSPL) to study the microphysics of optically thick clouds. Designed to measure enhanced backscattering and depolarization ratio comparable to space-borne lidar, the system consists of four sets of parallel and perpendicular channels mounted with different zenith angles. Depolarization ratios from water clouds were large as observed by MFMSPL compared to those observed by conventional lidar. Cloud top heights and depolarization ratios tended to be larger for outer MFMSPL channels than for vertically pointing channels. Co-located 95 GHz cloud radar and MFMSPL observations showed reasonable agreement at the observed cloud top height.
Zhou, Rui-Rui; Li, Ben-Wen
2017-03-01
In this study, the Chebyshev collocation spectral method (CCSM) is developed to solve the radiative integro-differential transfer equation (RIDTE) for one-dimensional absorbing, emitting and linearly anisotropic-scattering cylindrical medium. The general form of quadrature formulas for Chebyshev collocation points is deduced. These formulas are proved to have the same accuracy as the Gauss-Legendre quadrature formula (GLQF) for the F-function (geometric function) in the RIDTE. The explicit expressions of the Lagrange basis polynomials and the differentiation matrices for Chebyshev collocation points are also given. These expressions are necessary for solving an integro-differential equation by the CCSM. Since the integrand in the RIDTE is continuous but non-smooth, it is treated by the segments integration method (SIM). The derivative terms in the RIDTE are carried out to improve the accuracy near the origin. In this way, a fourth order accuracy is achieved by the CCSM for the RIDTE, whereas it's only a second order one by the finite difference method (FDM). Several benchmark problems (BPs) with various combinations of optical thickness, medium temperature distribution, degree of anisotropy, and scattering albedo are solved. The results show that present CCSM is efficient to obtain high accurate results, especially for the optically thin medium. The solutions rounded to seven significant digits are given in tabular form, and show excellent agreement with the published data. Finally, the solutions of RIDTE are used as benchmarks for the solution of radiative integral transfer equations (RITEs) presented by Sutton and Chen (JQSRT 84 (2004) 65-103). A non-uniform grid refined near the wall is advised to improve the accuracy of RITEs solutions.
Effects of Nuclear Medium on the Sum Rules in Electron and Neutrino Scattering
Zaidi, F; Athar, M Sajjad; Singh, S K; Simo, I Ruiz
2016-01-01
In this work, we study the influence of nuclear medium effects on various parton model sum rules in nuclei and compare the results with the free nucleon case. We have used relativistic nucleon spectral function to take into account Fermi motion, binding and nucleon correlations. The pion and rho meson cloud contributions have been incorporated in a microscopic model. The effect of shadowing has also been considered.
Medium effects in the deep-inelastic charged lepton/neutrino-A scattering
Haider, H; Athar, M Sajjad; Singh, S K; Simo, I Ruiz
2016-01-01
In this work, we have discussed the recent developments that have taken place to understand the differences in the weak $F_{2A}^{Weak} (x,Q^2)$ and electromagnetic $F_{2A}^{EM} (x,Q^2)$ nuclear structure functions. Also we present the results of our work on nuclear medium effects on $F_{2A}^{Weak} (x,Q^2)$ and $F_{2A}^{EM} (x,Q^2)$ for a wide range of $x$ and $Q^2$. These results have been obtained using a microscopic nuclear model, where to incorporate nuclear medium effects, Fermi motion, binding energy, nucleon correlations, mesonic contributions from pion and rho mesons and shadowing effects are considered. The calculations are performed in local density approximation using relativistic nucleon spectral function. We have also compared the theoretical results with the recent experimental data on electromagnetic and weak structure functions. Furthermore, we have studied the nuclear medium effects in Drell-Yan(DY) process and present the results for differential cross section, and the results are compared wi...
Li, Jia; Chen, Feinan
2016-11-01
Based on the first-order Born approximation, formulas are derived for the correlation between intensity fluctuations (CIF) of light generated by a Young’s diffractive electromagnetic wave scattered by a spatially quasi-homogeneous (QH), anisotropic medium. It is shown that the CIF of the scattered field can be written as the summation of the Fourier transforms of the strengths and normalized correlation coefficients (NCCs) of the scattering potentials. The differences between our results and those obtained in the previous literature are discussed. Our results might be important in investigating the high-order intensity correlation of an electromagnetic wave scattered from a 3D anisotropic object.
Evaluation of a multiple scattering filter to enhance defect detection in heterogeneous media.
Shahjahan, Sharfine; Rupin, Fabienne; Aubry, Alexandre; Derode, Arnaud
2017-01-01
Ultrasonic evaluation of coarse-grain materials generates multiple scattering at high frequency and large depth. Recent academic experiments with array probes showed the ability of a random matrix method [multiple scattering filter (MSF)] to reduce multiple scattering, hence improving detection. Here, MSF is applied to an industrial nickel-based alloy with coarse-grain structure. Two samples with average grain sizes 90 ± 60 μm and 750 ± 400 μm are inspected with wide-band 64-element arrays at central frequencies 2, 3, and 5 MHz. They contain cylindrical through-holes (1-mm radius) at various depths. The array transfer matrix is recorded and post-processed both in the flawless area and for eleven positions above each defect, which allows for a statistical analysis. MSF is compared with two conventional imaging techniques: the total focusing method (TFM) and the decomposition of the time-reversal operator (DORT). Several parameters to assess the performance of detection techniques are proposed and discussed. The results show the benefit of MSF, especially at high frequencies and for deep defects: at 5 MHz and 70 mm depth, i.e., more than three scattering mean-free paths, the detection rate for MSF ranges between 55% and 100% while it is found to be 0% both for TFM and DORT.
Optical scattering by a nonlinear medium, II: induced photonic crystal in a nonlinear slab of BBO
Godard, Pierre; Nicolet, Andre
2010-01-01
The purpose of this paper is to investigate the scattering by a nonlinear crystal whose depth is about the wavelength of the impinging field. More precisely, an infinite nonlinear slab is illuminated by an incident field which is the sum of three plane waves of the same frequency, but with different propagation vectors and amplitudes, in such a way that the resulting incident field is periodic. Moreover, the height of the slab is of the same order of the wavelength, and therefore the so-called slowly varying envelope approximation cannot be used. In our approach we take into account some retroactions of the scattered fields between them (for instance, we do not use the nondepletion of the pump beam). As a result, a system of coupled nonlinear partial differential equations has to be solved. To do this, the finite element method (FEM) associated with perfectly matched layers is well suited. Nevertheless, when using the FEM, the sources have to be located in the meshed area, which is of course impossible when d...
The energy transport in a vegetated (corn) surface layer is examined by solving the vector radiative transfer equation using a numerical iterative approach. This approach allows a higher order that includes the multiple scattering effects. Multiple scattering effects are important when the optical t...
Ghazali, A.; Serre, J.
1985-02-01
Using a multiple-scattering method, we estimate the relative importance of both scattering and concentration-fluctuation effects on the band tailing and on interband optical absorption spectra. In addition, we show that as the impurity concentration decreases, the band tail gradually splits off from the main band, forming an impurity band. Spectral-density analysis allows one to distinguish between quasi-atomic and extended states. It is found that even when no gap appears, a significant part of electrons in the tail has a quasi-atomic character. Compensation effects have also been analyzed. Finally, our results are discussed and compared with various experiments.
Parity violating asymmetry with nuclear medium effects in deep inelastic $\\vec e$ scattering
Haider, H; Singh, S K; Simo, I Ruiz
2014-01-01
Recently at JLab using polarised electron beam on unpolarised deuteron target measurements have been performed for the parity violating asymmetry($A_{PV}$) and there are future plans to measure this asymmetry using various nuclear targets. In this paper, we study $A_{PV}$ in nuclear targets like $^{12}C$, $^{56}Fe$ and $^{208}Pb$, in a local density approximation using spectral function which takes into account Fermi motion, binding energy correction and nucleon correlations. Furthermore, the pion and rho cloud contributions have also been taken into account. The present model has been used earlier to study medium effects in electromagnetic as well as weak interaction induced processes in the DIS region.
Study on two-cell stimulated Brillouin scattering system with mixture medium
Institute of Scientific and Technical Information of China (English)
HASI; Wuliji
2007-01-01
In this paper,a method of choosing mixture medium in two-cell stimulated Brillouinscattering(SBS)system to improve the system performance is proposed.The Brillouin frequency shift(BFS)of mixture medium varies with the mixing ratio andthus the difference of the BFS between the two cells can be eliminated.The two-cellSBS system with acetone(C3H6O)in its generator cell and mixture liquid ofCCl4/C2Cl4 in its amplifier cell is investigated.The C3H6O has a high optical breakdown threshold and the mixture liquid of CCl4/C2Cl4 has a small absorption coeffi-cient and the same BFS as that of C3H6O when the volume fraction of CCl4 is 4%.Compared with two-cell SBS system with the same liquid(C2Cl4)or different liquid(C3H6O and C2Cl4)in generator and amplifier cell,the SBS system with mixture liq-uid(CCl4/C2Cl4)in amplifier cell and C3H6O in generator cell improves thepower-load,energy reflectivity(ER),phase conjugation(PC)fidelity and ER stabil-ity.
Momentum-space treatment of Coulomb distortions in a multiple-scattering expansion
Energy Technology Data Exchange (ETDEWEB)
Chinn, C.R. (Physics Department, Lawrence Livermore National Laboratory, Livermore, California (USA)); Elster, C. (Department of Physics, Ohio State University, Columbus, Ohio (USA)); Thaler, R.M. (Los Alamos National Laboratory, Los Alamos, New Mexico (USA) Department of Physics, Case Western Reserve University, Cleveland, Ohio (USA))
1991-10-01
The momentum-space treatment of the Coulomb interaction within the framework of the Watson multiple-scattering expansion is derived and tested numerically. By neglecting virtual Coulomb excitations and higher-order terms, the lowest-order optical potential for proton-nucleus scattering is shown to be the sum of the convolutions of a two-body nucleon-nucleon {ital t} matrix with the nuclear density and the point Coulomb interaction with the nuclear charge density. The calculation of the optical potential, as well as the treatment of the Coulomb interaction, is performed entirely in momentum space in an exact and numerically stable procedure. Elastic-scattering observables are presented for {sup 16}O, {sup 40}Ca, and {sup 208}Pb at energies up to 500 MeV. Comparisons are made with approximate treatments of the Coulomb interaction. The interference of nonlocality effects in the nuclear optical potential with different treatments of the Coulomb interaction is investigated.
Momentum-space treatment of Coulomb distortions in a multiple-scattering expansion
Chinn, C. R.; Elster, Ch.; Thaler, R. M.
1991-10-01
The momentum-space treatment of the Coulomb interaction within the framework of the Watson multiple-scattering expansion is derived and tested numerically. By neglecting virtual Coulomb excitations and higher-order terms, the lowest-order optical potential for proton-nucleus scattering is shown to be the sum of the convolutions of a two-body nucleon-nucleon t matrix with the nuclear density and the point Coulomb interaction with the nuclear charge density. The calculation of the optical potential, as well as the treatment of the Coulomb interaction, is performed entirely in momentum space in an exact and numerically stable procedure. Elastic-scattering observables are presented for 16O, 40Ca, and 208Pb at energies up to 500 MeV. Comparisons are made with approximate treatments of the Coulomb interaction. The interference of nonlocality effects in the nuclear optical potential with different treatments of the Coulomb interaction is investigated.
Multiple scattering of light in cold atomic clouds with a magnetic field
Sigwarth, Olivier; Delande, Dominique; Miniatura, Christian
2013-01-01
Starting from a microscopic theory for atomic scatterers, we describe the scattering of light by a single atom and study the coherent propagation of light in a cold atomic cloud in the presence of a magnetic field B in the mesoscopic regime. Non-pertubative expressions in B are given for the magneto-optical effects and optical anisotropy. We then consider the multiple scattering regime and address the fate of the coherent backscattering (CBS) effect. We show that, for atoms with nonzero spin in their ground state, the CBS interference contrast can be increased compared to its value when B=0, a result at variance with classical samples. We validate our theoretical results by a quantitative comparison with experimental data.
Implications of multiple scattering on the assessment of black carbon aerosol radiative forcing
Nair, Vijayakumar S.; Suresh Babu, S.; Krishna Moorthy, K.; Satheesh, S. K.
2014-11-01
The effects of radiative coupling between scattering and absorbing aerosols, in an external mixture, on the aerosol radiative forcing (ARF) due to black carbon (BC), its sensitivity to the composite aerosol loading and composition, and surface reflectance are investigated using radiative transfer model simulations. The ARF due to BC is found to depend significantly on the optical properties of the ‘neighboring’ (non-BC) aerosol species. The scattering due to these species significantly increases the top of the atmospheric warming due to black carbon aerosols, and significant changes in the radiative forcing efficiency of BC. This is especially significant over dark surfaces (such as oceans), despite the ARF due to BC being higher over snow and land-surfaces. The spatial heterogeneity of this effect (coupling or multiple scattering by neighboring aerosol species) imposes large uncertainty in the estimation ARF due to BC aerosols, especially over the oceans.
Energy Technology Data Exchange (ETDEWEB)
Jalabert, D.; Rouviere, J.L. [CEA-INAC/UJF-Grenoble 1 UMR-E, SP2M, LEMMA, MINATEC Campus, Grenoble (France); Pelloux-Gervais, D.; Canut, B. [Institut des Nanotechnologies de Lyon, Universite de Lyon, INL-UMR5270, CNRS, INSA de Lyon, Villeurbanne 69621 (France); Beche, A. [CEA-INAC/UJF-Grenoble 1 UMR-E, SP2M, LEMMA, MINATEC Campus, Grenoble (France); FEI Company, Eindhoven (Netherlands); Hartmann, J.M.; Gergaud, P. [CEA-Leti, MINATEC, Grenoble (France)
2012-02-15
The depth strain profile in silicon from the Si(001) substrate to the surface of a 2 nm thick Si/12 nm thick SiGe/bulk Si heterostructure has been determined by medium energy ion scattering (MEIS). It shows with sub-nanometer resolution and high strain sensitivity that the thin Si cap presents residual compressive strain caused by Ge diffusion coming from the fully strained SiGe layer underneath. The strain state of the SiGe buffer have been checked by X-ray diffraction (XRD) and nano-beam electron diffraction (NBED) measurements. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Li, Meng; Jiang, Li-Hui; Xiong, Xing-Long; Ma, Yu-Zhao; Liu, Jie-Sheng
2016-08-01
Layer boundaries detection with LIDAR is of great significance for the meteorological and environmental research. Apart from the background noise, multiple scattering can also seriously affect the detection results in LIDAR signal processing. To alleviate these issues, a novel approach was proposed based upon morphological filtering and multiple scattering correction with multiple iterations, which essentially acts as a weighted algorithm with multiple scattering factors in different filtering scales, and applies integral extinction coefficients as media to perform correction. Simulations on artificial signals and real LIDAR signals support this approach.
Magnetotransport of multiple-band nearly antiferromagnetic metals due to hot-spot scattering
Koshelev, A. E.
2016-09-01
Multiple-band electronic structure and proximity to antiferromagnetic (AF) instability are the key properties of iron-based superconductors. We explore the influence of scattering by the AF spin fluctuations on transport of multiple-band metals above the magnetic transition. A salient feature of scattering on the AF fluctuations is that it is strongly enhanced at the Fermi surface locations where the nesting is perfect ("hot spots" or "hot lines"). We review derivation of the collision integral for the Boltzmann equation due to AF-fluctuations scattering. In the paramagnetic state, the enhanced scattering rate near the hot lines leads to anomalous behavior of electronic transport in magnetic field. We explore this behavior by analytically solving the Boltzmann transport equation with approximate transition rates. This approach accounts for return scattering events and is more accurate than the relaxation-time approximation. The magnetic-field dependences are characterized by two very different field scales: the lower scale is set by the hot-spot width and the higher scale is set by the total scattering amplitude. A conventional magnetotransport behavior is limited to magnetic fields below the lower scale. In the wide range in-between these two scales, the longitudinal conductivity has linear dependence on the magnetic field and the Hall conductivity has quadratic dependence. The linear dependence of the diagonal component reflects growth of the Fermi-surface area affected by the hot spots proportional to the magnetic field. We discuss applicability of this theoretical framework for describing of anomalous magnetotransport properties in different iron pnictides and chalcogenides in the paramagnetic state.
Palazzi, E.; Premuda, M.; Petritoli, A.; Giovanelli, G.; Kostadinov, I.; Ravegnani, F.; Bortoli, D.
A correct interpretation of diffuse solar radiation measurements made by DOAS (Differential Optical Absorption Spectroscopy) remote sensors, requires the use of radiative transfer models of the atmosphere. The simplest models, the geometrical ones, consider radiation scattering in the atmosphere as a single scattering process. This means that the photons collected by the receiver have changed their direction from the sun only once. More realistic atmospheric models are those which consider multiple scattering: their application is useful and essential for the analysis of zenith and off-axis measurements regarding the lowest layers of the atmosphere, characterized by the highest values of air density and quantities of particles and aerosols acting as scattering nuclei. A new atmospheric model, called PROMSAR (PROcessing of Multi-Scattered Atmospheric Radiation), including multiple Rayleigh and Mie scattering, has recently been developed at the ISAC-CNR institute. It is based on a backward Monte Carlo technique, very suitable for studying the various interactions taking place in a complex and non-homogeneous system like the terrestrial atmosphere. PROMSAR code calculates the mean path of the radiation within each layer into which the atmosphere is sub-divided, taking into account the large variety of processes which solar radiation undergoes during propagation through the atmosphere. This quantity is then employed to work out the Air Mass Factor (AMF) of several trace gases, to simulate, both in zenith and off-axis configurations, their slant column amounts and to calculate the weighting functions from which information about the gas vertical distribution is obtained using inversion methods. Results from the model, simulations and comparisons with slant column measurements are presented and discussed.
An anisotropic negative refractive index medium operated at multiple-angle incidences.
Yang, Tien-Chung; Yang, Yu-Hang; Yen, Ta-Jen
2009-12-21
Recently metamaterials have been demonstrating new physics to enable various unprecedented electromagnetic properties, but pratically they are so sensitive to incident angles of the external excitation that their applications are restricted. Therefore, we present an anisotropic negative refractive index medium operated at multiple-angle incidences (NRIM for MAI) to ease such a burden. Both the simulated and measured transmittance, reflectance and the corresponding material parameters indicate that our structure does possess the anisotropic negative refractive index with respect to different incident angles. In addition, the opposite directions of group and phase velocities are also demonstrated under both grazing-angle, normal and 45-degree incidences to further verify the negative refractive index of the designed monolithic NRIM structure for multiple-angle incidences.
Multiple-mode Lamb wave scattering simulations using 3D elastodynamic finite integration technique.
Leckey, Cara A C; Rogge, Matthew D; Miller, Corey A; Hinders, Mark K
2012-02-01
We have implemented three-dimensional (3D) elastodynamic finite integration technique (EFIT) simulations to model Lamb wave scattering for two flaw-types in an aircraft-grade aluminum plate, a rounded rectangle flat-bottom hole and a disbond of the same shape. The plate thickness and flaws explored in this work include frequency-thickness regions where several Lamb wave modes exist and sometimes overlap in phase and/or group velocity. For the case of the flat-bottom hole the depth was incrementally increased to explore progressive changes in multiple-mode Lamb wave scattering due to the damage. The flat-bottom hole simulation results have been compared to experimental data and are shown to provide key insight for this well-defined experimental case by explaining unexpected results in experimental waveforms. For the rounded rectangle disbond flaw, which would be difficult to implement experimentally, we found that Lamb wave behavior differed significantly from the flat-bottom hole flaw. Most of the literature in this field is restricted to low frequency-thickness regions due to difficulties in interpreting data when multiple modes exist. We found that benchmarked 3D EFIT simulations can yield an understanding of scattering behavior for these higher frequency-thickness regions and in cases that would be difficult to set up experimentally. Additionally, our results show that 2D simulations would not have been sufficient for modeling the complicated scattering that occurred.
Hashemi, Roohollah
2017-03-01
In this paper, a robust methodology with several desirable features is developed for the determination of the magneto-electro-elastic fields of a shear (SH) wave scattered by a two-phase multiferroic fiber embedded in an infinite transversely isotropic piezoelectric or piezomagnetic medium. While the traditional wave-function expansion approach commonly used in the literature ceases to hold when the geometry of the obstacle is not symmetric, the present theory is capable of treating eccentric coating-fiber ensemble. To put its wide range of applicability in perspective, my analytical methodology is applied to several descriptive examples with various degrees of complexity. The calculated results reveals the profound influence of material properties of constituent phases, the thickness and eccentricity of coating layer, as well as the frequency of propagating SH-wave on the pertinent scattered fields induced by the multiferroic fiber. It is expected that the formulation and numerical results of this paper serve as a useful reference for the design and manufacture of multiferroic materials with a durable and yet reliable performance under dynamics loadings.
Energy Technology Data Exchange (ETDEWEB)
Chen, Xueli, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn; Zhang, Qitan; Yang, Defu; Liang, Jimin, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn [School of Life Science and Technology, Xidian University, Xi' an, Shaanxi 710071 (China)
2014-01-14
To provide an ideal solution for a specific problem of gastric cancer detection in which low-scattering regions simultaneously existed with both the non- and high-scattering regions, a novel hybrid radiosity-SP{sub 3} equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP{sub 3}) was combined with the radiosity equation to describe the bioluminescent light propagation in tissues, which provided acceptable accuracy for the turbid medium with both low- and non-scattering regions. The performance of the algorithm was evaluated with digital mouse based simulations and a gastric cancer-bearing mouse based in situ experiment. Primary results demonstrated the feasibility and superiority of the proposed algorithm for the turbid medium with low- and non-scattering regions.
Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target
Adolph, C.; Aghasyan, M.; Akhunzyanov, R.; Alexeev, M. G.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C. D. R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Capozza, L.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S.-U.; Cicuttin, A.; Crespo, M. L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Dhara, L.; Donskov, S. V.; Doshita, N.; Dreisbach, Ch.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P. D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F. H.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O. M.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G. K.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G. V.; Meyer, M.; Meyer, W.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A. S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Roskot, M.; Rossiyskaya, N. S.; Ryabchikov, D. I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Sozzi, F.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Thiel, A.; Tosello, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Vondra, J.; Wallner, S.; Weisrock, T.; Wilfert, M.; Windmolders, R.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Zink, A.
2017-04-01
Precise measurements of charged-kaon multiplicities in deep inelastic scattering were performed. The results are presented in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6LiD target. They cover the kinematic domain 1(GeV / c) 2 5 GeV /c2 in the invariant mass of the hadronic system. The results from the sum of the z-integrated K+ and K- multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit.
Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target
Directory of Open Access Journals (Sweden)
C. Adolph
2017-04-01
Full Text Available Precise measurements of charged-kaon multiplicities in deep inelastic scattering were performed. The results are presented in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6LiD target. They cover the kinematic domain 1(GeV/c25 GeV/c2 in the invariant mass of the hadronic system. The results from the sum of the z-integrated K+ and K− multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit.
Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target
Adolph, C.
2017-01-01
Precise measurements of charged-kaon multiplicities in deep inelastic scattering were performed. The results are presented in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6 LiD target. They cover the kinematic domain 1 (GeV/c)2 5 GeV/c^2 in the invariant mass of the hadronic system. The results from the sum of the z-integrated K+ and K- multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit.
Mann, Nishan
2016-01-01
We introduce a new coupled mode theory to model nonlinear Schr\\"{o}dinger equations for contra-propagating Bloch modes that include disorder-induced multiple scattering effects on nonlinear soliton propagation in photonic crystal waveguides. We also derive sub unit-cell coupling coefficients and use these to introduce a generalized length scale associated with each coupling effect. In particular, we define a multiple-scattering length scale that quantifies the spatial extent of a disorder-induced cavity mode. Our numerical simulations of nonlinear pulse propagation are in excellent qualitative agreement with recent experiments and provide insight into how disorder inhibits soliton propagation and other nonlinear propagation effects in photonic crystal waveguides.
Neutron Densities from a Global Analysis of Medium Energy Proton Nucleus Elastic Scattering
Clark, B C; Kerr, L J
2003-01-01
A new method for extracting neutron densities from intermediate energy elastic proton-nucleus scattering observables uses a global Dirac phenomenological (DP) approach based on the Relativistic Impulse Approximation (RIA). Data sets for Ca40, Ca48 and Pb208 in the energy range from 500 MeV to 1040 MeV are considered. The global fits are successful in reproducing the data and in predicting data sets not included in the analysis. Using this global approach, energy independent neutron densities are obtained. The vector point proton density distribution is determined from the empirical charge density after unfolding the proton form factor. The other densities are parametrized. The RMS neutron radius, R_n and the neutron skin thickness S_n obtained from the global fits using the most conservative errors are given as follows: for Ca40 R_n is (3.325 +/- 0.025) fm and S_n (-0.044 +/- 0.036) fm; for Ca48 R_n is (3.463 +/- 0.042) fm and S_n (0.103 +/- 0.045) fm; and for Pb208 R_n is (5.551 +/- 0.038) and S_n (0.116 +/-...
Shettle, E. P.; Green, A. E. S.
1974-01-01
An investigation is conducted regarding the increase in the UV radiation as a function of wavelength due to changes in the amounts of ozone and various other parameters affecting the radiation in the atmosphere. Attention is given to the methods that can be used to solve the problem of the transfer of radiation through an absorbing and scattering atmosphere which includes aerosols. The multiple channel solution reported by Mudgett and Richards' (1971) is extended to vertically inhomogeneous atmospheres.
Coulomb Corrections to the Parameters of the Moliere Multiple Scattering Theory
Kuraev, Eduard; Tarasov, Alexander
2013-01-01
High-energy Coulomb corrections to the parameters of the Moliere multiple scattering theory are obtained. Numerical calculations are presented in the range of the nuclear charge number of the target atom 4
Photon Radiation Induced by Multiple Parton Rescattering in Deeply Inelastic Scattering
Institute of Scientific and Technical Information of China (English)
张本威; 王恩科
2003-01-01
Photon radiation induced by multiple parton rescattering and corresponding parton energy loss in eA deeply inelastic scattering are investigated by using the generalized factorization of higher twist parton distributions beyond the helicity amplitude approximation. It turns out that the behaviour of the nuclear size dependence of the parton energy loss is different in the photon and gluon radiation cases. The parton energy loss due to photon radiation depends linearly, instead of quadratically, on nuclear size due to gluon radiation.
Atmospheric neutrino oscillations from upward throughgoing muon multiple scattering in MACRO
Ambrosio, M; Bakari, D; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Becherini, Y; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bower, C; Brigida, M; Bussino, S; Cafagna, F; Calicchio, M; Campana, D; Carboni, M; Caruso, R; Cecchini, S; Cei, F; Chiarella, V; Chiarusi, T; Choudhary, B C; Coutu, S; Cozzi, M; De Cataldo, G; Dekhissi, H; De Marzo, C; De Mitri, I; Derkaoui, J E; De Vincenzi, M; Di Credico, A; Favuzzi, C; Forti, C; Fusco, P; Giacomelli, G; Giannini, G; Giglietto, N; Giorgini, M; Grassi, M; Grillo, A; Gustavino, C; Habig, A; Hanson, K; Heinz, R; Katsavounidis, E; Katsavounidis, I; Kearns, E; Kim, H; Kumar, A; Kyriazopoulou, S; Lamanna, E; Lane, C; Levin, D S; Lipari, P; Longo, M J; Loparco, F; Maaroufi, F; Mancarella, G; Mandrioli, G; Manzoor, S; Margiotta, A; Marini, A; Martello, D; Marzari-Chiesa, A; Mazziotta, M N; Michael, D G; Mikheyev, S P; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S L; Musser, J; Nicolò, D; Nolty, R; Orth, C; Osteria, G; Palamara, O; Patrizii, L; Pazzi, R; Peck, C W; Perrone, L; Petrera, S; Popa, V; Rainó, A; Reynoldson, J; Ronga, F; Rrhioua, A; Satriano, C; Scapparone, E; Scholberg, K; Sciubba, A; Serra, P; Sioli, M; Sirri, G; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, L R; Surdo, A; Tarle, G; Togo, V; Vakili, M; Walter, C W; Webb, R; 10.1016/S0370-2693(03)00806-2
2003-01-01
The energy of atmospheric neutrinos detected by MACRO was estimated using multiple coulomb scattering of upward throughgoing muons. This analysis allows a test of atmospheric neutrino oscillations, relying on the distortion of the muon energy distribution. These results have been combined with those coming from the upward throughgoing muon angular distribution only. Both analyses are independent of the neutrino flux normalization and provide strong evidence, above the 4 sigma level, in favour of neutrino oscillations.
Treatment of multiple scattering with the generalized Riemann sphere track fit
Strandlie, A; Frühwirth, R
2002-01-01
In this paper, we present a generalization of the Riemann sphere track fitting method. This generalization makes it possible to efficiently include multiple scattering effects in the estimation procedure. We also show that the Riemann fit can be formulated in an alternative way through a mapping to a paraboloid. This yields results equivalent to the standard formulation, but with the added advantage that measurements with errors both in RPhi as well as in the radial direction can be handled in a straightforward manner.
Multiple-scattering corrections in diluted magnetic semiconductors: A plane-wave expansion
Scalbert, D.; Ghazali, A.; Benoit à la Guillaume, C.
1993-12-01
Energy levels of band edges in diluted magnetic semiconductors are calculated in the effective-mass approximation, retaining off-diagonal terms in the exchange interaction and using a plane-wave expansion. This model accounts qualitatively for the observed asymmetry in the splitting of the A exciton in a magnetic field in Cd1-xMnxS for which multiple-scattering corrections are expected to be important.
Stopping cross sections of protons in Ti, TiO2 and Si using medium energy ion scattering
Brocklebank, Mitchell; Dedyulin, Sergey N.; Goncharova, Lyudmila V.
2016-11-01
Stopping cross sections of protons in Ti, Si, and TiO2 films in the energy range 50-170 keV were determined from medium energy ion scattering (MEIS) spectra by an iterative procedure. The energy loss of protons was investigated for pure Ti and Si films, deposited by molecular beam epitaxy (MBE) onto n-Si(100) and diamond-like carbon (DLC) substrates respectively. Consecutive annealing of Ti at 200 °C in O2 resulted in stoichiometric TiO2 thin-films. Thickness and composition of the films and the interfacial properties were determined using Rutherford backscattering spectroscopy (RBS), MEIS, and X-ray photoelectron spectroscopy (XPS). Calculated stopping cross sections of Ti, Si, and TiO2 in the range of energies were compared with the commonly used SRIM2003 values. For Ti and Si, SRIM2003 values appear to be overestimated over the entire energy range. The new stopping cross sections explain deviations from previously reported values for SrTiO3. We note that the stopping cross sections of O in a gaseous phase, used in Bragg's rule calculations, cannot be applied for accurate quantitative ion beam analysis in solid compounds in the medium ion energy range.
Khromova, A N; Arfelli, F; Menk, R H; Besch, H J; Plothow-Besch, H; 10.1109/NSSMIC.2004.1466758
2010-01-01
In this work we present a novel 3D Monte Carlo photon transport program for simulation of multiple refractive scattering based on the refractive properties of X-rays in highly scattering media, like lung tissue. Multiple scattering reduces not only the quality of the image, but contains also information on the internal structure of the object. This information can be exploited utilizing image modalities such as Diffraction Enhanced Imaging (DEI). To study the effect of multiple scattering a Monte Carlo program was developed that simulates multiple refractive scattering of X-ray photons on monodisperse PMMA (poly-methyl-methacrylate) microspheres representing alveoli in lung tissue. Eventually, the results of the Monte Carlo program were compared to the measurements taken at the SYRMEP beamline at Elettra (Trieste, Italy) on special phantoms showing a good agreement between both data.
Doc, Jean-Baptiste; Conoir, Jean-Marc; Marchiano, Régis; Fuster, Daniel
2016-04-01
The weakly nonlinear propagation of acoustic waves in monodisperse bubbly liquids is investigated numerically. A hydrodynamic model based on the averaged two-phase fluid equations is coupled with the Rayleigh-Plesset equation to model the dynamics of bubbles at the local scale. The present model is validated in the linear regime by comparing with the Foldy approximation. The analysis of the pressure signals in the linear regime highlights two resonance frequencies: the Minnaert frequency and a multiple scattering resonance that strongly depends on the bubble concentration. For weakly nonlinear regimes, the generation of higher harmonics is observed only for the Minnaert frequency. Linear combinations between the Minnaert harmonics and the multiple scattering resonance are also observed. However, the most significant effect observed is the appearance of softening-hardening effects that share some similarities with those observed for sandstones or cracked materials. These effects are related to the multiple scattering resonance. Downward or upward resonance frequency shifts can be observed depending on the characteristic of the incident wave when increasing the excitation amplitude. It is shown that the frequency shift can be explained assuming that the acoustic wave velocity depends on a law different from those usually encountered for sandstones or cracked materials.
Exploiting azimuthal variance of scatterers for multiple-look SAR recognition
Bhanu, Bir; Jones, Grinnell, III
2002-08-01
The focus of this paper is optimizing the recognition of vehicles in Synthetic Aperture Radar (SAR) imagery using multiple SAR recognizers at different look angles. The variance of SAR scattering center locations with target azimuth leads to recognition system results at different azimuths that are independent, even for small azimuth deltas. Extensive experimental recognition results are presented in terms of receiver operating characteristic (ROC) curves to show the effects of multiple look angles on recognition performance for MSTAR vehicle targets with configuration variants, articulation, and occlusion.
Patterson, M.; Hughes, S.; Schulz, S.; Beggs, D. M.; White, T. P.; O'Faolain, L.; Krauss, T. F.
2009-11-01
Through a combined theoretical and experimental study of disorder-induced incoherent scattering losses in slow-light photonic crystal slab waveguides, we show the importance of Bloch mode reshaping and multiple scattering. We describe a convenient and fully three-dimensional theoretical treatment of disorder-induced extrinsic scattering, including the calculation of backscatter and out-of-plane losses per unit cell, and the extrapolation of the unit-cell loss to the loss for an entire disordered waveguide. The theoretical predictions, which are also compared with recent measurements on dispersion engineered silicon waveguides, demonstrate the failure of the Beer-Lambert law due to multiple scattering. We also explain why the previously assumed group velocity scalings of disorder-induced loss break down in general.
Directory of Open Access Journals (Sweden)
V. V. Rozanov
2010-06-01
Full Text Available The Differential Optical Absorption Spectroscopy (DOAS technique is widely used to retrieve amounts of atmospheric species from measurements of the direct solar light transmitted through the Earth's atmosphere as well as of the solar light scattered in the atmosphere or reflected from the Earth's surface. For the transmitted direct solar light the theoretical basis of the DOAS technique represented by the Beer-Lambert law is well studied. In contrast, scarcely investigated is the theoretical basis and validity range of the DOAS method for those cases where the contribution of the multiple scattering processes is not negligible. Our study is intended to fill this gap by means of a theoretical investigation of the applicability of the DOAS technique for the retrieval of amounts of atmospheric species from observations of the scattered solar light with a non-negligible contribution of the multiple scattering.
Starting from the expansion of the intensity logarithm in the functional Taylor series we formulate the general form of the DOAS equation. The thereby introduced variational derivative of the intensity logarithm with respect to the variation of the gaseous absorption coefficient, which is often referred to as the weighting function, is demonstrated to be closely related to the air mass factor. Employing some approximations we show that the general DOAS equation can be rewritten in the form of the weighting function (WFDOAS, the modified (MDOAS, and the standard DOAS equations. For each of these forms a specific equation for the air mass factor follows which, in general, is not suitable for other forms of the DOAS equation. Furthermore, the validity range of the standard DOAS equation is quantitatively investigated using a suggested criterion of a weak absorption.
The results presented in this study are intended to provide a basis for a better understanding of the applicability range of different forms of the DOAS equation as
The multiple scattering and N-body approaches to nuclear reactions
Picklesimer, A.; Tandy, P. C.; Thaler, R. M.
1983-02-01
The relationship between conventional multiple scattering approaches and the recently developed N-body approaches to nuclear reactions is considered with a view towards elastic scattering applications. Connectivity expansions in the N-body approach and multiple scattering expansions in the Watson approach are developed by a common technique so that a comparison of the physical content of each can be made. In the N-body case this leads to a new derivation of the equations of Bencze, Redish, and Sloan in both particle-labelled and partition-labelled form and this yields new insight into the minimal dimensionality of these equations and into the role of channel coupling schemes within this formulation. The relative simplicity and generality with which these results are obtained is designed to be easily understood by those unfamiliar with N-body formalisms. The two approaches are contrasted first for the three-particle problem and subsequently for the many-body problem. We argue that a strict adherence to the connected-kernel property which is advantageous for the three-particle problem may not be so advantageous for the many-body elastic scattering problem. Undesirable physical characteristics of the connectivity expansion for elastic scattering are identified and their rectification is discussed. The off-shell transformation associated with the N-body approach is examined critically. The origin of the multiplicity of N-body coupling schemes is elucidated. It is shown that a modified concept of connectivity, called inclusive connectivity, can be introduced to guide expansions which can be truncated in a physically meaningful way. The inclusive connectivity expansion is seen to be identical to the spectator expansion for an elementary projectile but differs in the case of a composite projectile. Extant elastic scattering optical potential formulations based on the two concepts of connectivity are compared and contrasted. We show that connected kernel integral equations
Konovalov, Aleksandr B.; Vlasov, V. V.; Kalintsev, A. G.; Kravtsenyuk, Olga V.; Lyubimov, Vladimir V.
2006-11-01
The inverse problem of diffuse optical tomography (DOT) is reduced by the method of photon average trajectories (PAT) to the solution of the integral equation integrated along the conditional mean statistical photon trajectory. The PAT bending near the flat boundary of a scattering medium is estimated analytically. These estimates are used to determine the analytic statistical characteristics of photon trajectories for the flat layer geometry. The inverse DOT problem is solved by using the multiplicative algebraic algorithm modified to improve the convergence of the iteration reconstruction process. The numerical experiment shows that the modified PAT method permits the reconstruction of near-surface optical inhomogeneities virtually without distortions.
Mass hierarchy sensitivity of medium baseline reactor neutrino experiments with multiple detectors
Wang, Hongxin; Li, Yu-Feng; Cao, Guofu; Chen, Shenjian
2016-01-01
We report the neutrino mass hierarchy (MH) sensitivity of medium baseline reactor neutrino experiments with multiple detectors. Sensitivity of determining the MH can be significantly improved by adding a near detector and combining both the near and far detectors. The size of the sensitivity improvement is related to accuracy of the individual mass-splitting measurements and requires strict control on the relative energy scale uncertainty of the near and far detectors. We study the impact of both baseline and target mass of the near detector on the combined sensitivity. A figure-of-merit is defined to optimize the baseline and target mass of the near detector and the optimal selections are $\\sim$13~km and $\\sim$4~kton respectively for a far detector with the 20~kton target mass and 52.5~km baseline. As typical examples of future medium baseline reactor neutrino experiments, the optimal location and target mass of the near detector are selected for JUNO and RENO-50. Finally, we discuss distinct effects of the ...
Ranging in an Underwater Medium with Multiple Isogradient Sound Speed Profile Layers
Directory of Open Access Journals (Sweden)
Hamid Ramezani
2012-03-01
Full Text Available In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment. The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP layers where in each layer the sound speed is linearly related to the depth. Furthermore, each sensor node is able to measure its depth and can exchange this information with other nodes. Under these assumptions, we first show how the problem of underwater localization can be converted to the traditional range-based terrestrial localization problem when the depth information of the nodes is known a priori. Second, we relate the pair-wise time of flight (ToF measurements between the nodes to their positions. Next, based on this relation, we propose a novel ranging algorithm for an underwater medium. The proposed ranging algorithm considers reflections from the seabed and sea surface. We will show that even without any reflections, the transmitted signal may travel through more than one path between two given nodes. The proposed algorithm analyzes them and selects the fastest one (first arrival path based on the measured ToF and the nodes’ depth measurements. Finally, in order to evaluate the performance of the proposed algorithm we run several simulations and compare the results with other existing algorithms.
Mass hierarchy sensitivity of medium baseline reactor neutrino experiments with multiple detectors
Energy Technology Data Exchange (ETDEWEB)
Wang, Hong-Xin, E-mail: hxwang@iphy.me [Department of Physics, Nanjing University, Nanjing 210093 (China); Zhan, Liang; Li, Yu-Feng; Cao, Guo-Fu [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chen, Shen-Jian [Department of Physics, Nanjing University, Nanjing 210093 (China)
2017-05-15
We report the neutrino mass hierarchy (MH) determination of medium baseline reactor neutrino experiments with multiple detectors, where the sensitivity of measuring the MH can be significantly improved by adding a near detector. Then the impact of the baseline and target mass of the near detector on the combined MH sensitivity has been studied thoroughly. The optimal selections of the baseline and target mass of the near detector are ∼12.5 km and ∼4 kton respectively for a far detector with the target mass of 20 kton and the baseline of 52.5 km. As typical examples of future medium baseline reactor neutrino experiments, the optimal location and target mass of the near detector are selected for the specific configurations of JUNO and RENO-50. Finally, we discuss distinct effects of the reactor antineutrino energy spectrum uncertainty for setups of a single detector and double detectors, which indicate that the spectrum uncertainty can be well constrained in the presence of the near detector.
Measurement of density and water content of soil using photon multiple scattering
Ertek, C.; Haselberger, N.
1984-11-01
A quantitative measure of density and of water content in soil was determined by photon multiple scattering following sample irradiation by a 0.7 mCi 137Cs source. Counting was effected using a stabilized single channel scintillation detector and counter system in the differential mode. Scattered photons of 80 keV energy were measured using a 20 keV window. The moving source method was applied to find the density of soil and count rate ratios of dry soil to wet soil. Independent calibrations were applied for the moisture measurements. Four curves were obtained for the soil density range of 0.5-1.5 g/cm 3 by using soil standards of 2.6, 7.0, 10.6 and 16.1 wt.% water content. Direct influence of photons was measured by blocking the direct path of photons to the detector by shielding both the Cs source and the detector.
A Multiple Scattering Polarized Radiative Transfer Model: Application to HD 189733b
Kopparla, Pushkar; Zhang, Xi; Swain, Mark R; Wiktorowicz, Sloane J; Yung, Yuk L
2015-01-01
We present a multiple scattering vector radiative transfer model which produces disk integrated, full phase polarized light curves for reflected light from an exoplanetary atmosphere. We validate our model against results from published analytical and computational models and discuss a small number of cases relevant to the existing and possible near-future observations of the exoplanet HD 189733b. HD 189733b is arguably the most well observed exoplanet to date and the only exoplanet to be observed in polarized light, yet it is debated if the planet's atmosphere is cloudy or clear. We model reflected light from clear atmospheres with Rayleigh scattering, and cloudy or hazy atmospheres with Mie and fractal aggregate particles. We show that clear and cloudy atmospheres have large differences in polarized light as compared to simple flux measurements, though existing observations are insufficient to make this distinction. Futhermore, we show that atmospheres that are spatially inhomogeneous, such as being partial...
Vynck, Kevin; Pierrat, Romain; Carminati, Rémi
2016-09-01
We develop a model based on a multiple scattering theory to describe the diffusion of polarized light in disordered media exhibiting short-range structural correlations. Starting from exact expressions of the average field and the field spatial correlation function, we derive a radiative transfer equation for the polarization-resolved specific intensity that is valid for weak disorder and we solve it analytically in the diffusion limit. A decomposition of the specific intensity in terms of polarization eigenmodes reveals how structural correlations, represented via the standard anisotropic scattering parameter g , affect the diffusion of polarized light. More specifically, we find that propagation through each polarization eigenchannel is described by its own transport mean free path that depends on g in a specific and nontrivial way.
Vynck, Kevin; Carminati, Rémi
2016-01-01
We develop a model based on a multiple scattering theory to describe the diffusion of polarized light in disordered media exhibiting short-range structural correlations. Starting from exact expressions of the average field and the field spatial correlation function, we derive a radiative transfer equation for the polarization-resolved specific intensity that is valid for weak disorder and we solve it analytically in the diffusion limit. A decomposition of the specific intensity in terms of polarization eigenmodes reveals how structural correlations, represented via the standard anisotropic scattering parameter $g$, affect the diffusion of polarized light. More specifically, we find that propagation through each polarization eigenchannel is described by its own transport mean free path that depends on $g$ in a specific and non-trivial way.
Full-potential multiple scattering theory with space-filling cells for bound and continuum states.
Hatada, Keisuke; Hayakawa, Kuniko; Benfatto, Maurizio; Natoli, Calogero R
2010-05-12
We present a rigorous derivation of a real-space full-potential multiple scattering theory (FP-MST) that is free from the drawbacks that up to now have impaired its development (in particular the need to expand cell shape functions in spherical harmonics and rectangular matrices), valid both for continuum and bound states, under conditions for space partitioning that are not excessively restrictive and easily implemented. In this connection we give a new scheme to generate local basis functions for the truncated potential cells that is simple, fast, efficient, valid for any shape of the cell and reduces to the minimum the number of spherical harmonics in the expansion of the scattering wavefunction. The method also avoids the need for saturating 'internal sums' due to the re-expansion of the spherical Hankel functions around another point in space (usually another cell center). Thus this approach provides a straightforward extension of MST in the muffin-tin (MT) approximation, with only one truncation parameter given by the classical relation l(max) = kR(b), where k is the electron wavevector (either in the excited or ground state of the system under consideration) and R(b) is the radius of the bounding sphere of the scattering cell. Moreover, the scattering path operator of the theory can be found in terms of an absolutely convergent procedure in the l(max) --> ∞ limit. Consequently, this feature provides a firm ground for the use of FP-MST as a viable method for electronic structure calculations and makes possible the computation of x-ray spectroscopies, notably photo-electron diffraction, absorption and anomalous scattering among others, with the ease and versatility of the corresponding MT theory. Some numerical applications of the theory are presented, both for continuum and bound states.
Continuous-wave spatial quantum correlations of light induced by multiple scattering
DEFF Research Database (Denmark)
Smolka, Stephan; Ott, Johan Raunkjær; Huck, Alexander;
2012-01-01
and reflectance. Utilizing frequency-resolved quantum noise measurements, we observe that the strength of the spatial quantum correlation function can be controlled by changing the quantum state of an incident bright squeezed-light source. Our results are found to be in excellent agreement with the developed......We present theoretical and experimental results on spatial quantum correlations induced by multiple scattering of nonclassical light. A continuous-mode quantum theory is derived that enables determining the spatial quantum correlation function from the fluctuations of the total transmittance...
Open problems in the optics of crystals: the role of multiple scattering.
Ponti, S; Oldano, C
2003-03-01
The thickness b of the transition boundary layer, always present in crystals and giving still unsolved problems for the boundary conditions, is shown to be essentially determined by the multiple scattering of light, due to the inhomogeneity of any periodic structure. The parameter b depends on the orientation theta of the boundary plane with respect to the crystal lattice, and diverges for some critical orientations where strong macroscopic effects are found, which cannot be interpreted by any macroscopic model based on bulk and boundary equations. Our analysis exhaustively defines the limits of validity of macroscopic models for periodic nanoscale structures and solid crystals.
Micro-scale Abrasion and Medium Load Multiple Scratch Tests of PVD Coatings.
Institute of Scientific and Technical Information of China (English)
S.Poulat; H.Sun; D.GTeer
2004-01-01
Micro-scale abrasion testing is widely used to determine the abrasion resistance of thin film coatings; it is a simple technique that can easily be used as part of a quality control procedure, but it has got the disadvantage of not allowing an easy study of the wear mechanisms involved: it is difficult to estimate the load applied on each abrasive particles in the contact between the loaded ball and the specimen. The possibility of using progressive loading scratch testing, a method widely used to assess the adhesion of thin film coatings, to model the abrasive wear of coatings has been studied in the past; the use of multiple scratch tests to study the wear mechanisms corresponding to a single abrasion scratch event has also been studied in the case of bulk materials (ceramics and hard metals). Two coatings, deposited by Closed Field Unbalanced Magnetron Sputter Ion Plating (CFUBMSIP) on ASP23 powder metallurgy steel substrate are chosen to be representative of the use of protective coatings in industry: titanium nitride, which is widely used to prevent tool wear, and TCL Graphit-iCTM, which is widely used as a wear resistant solid lubricant coating. The two coatings are first characterised by using a standard quality control procedure: their thickness is determined by the cap grinding method, their adhesion by progressive loading scratch. Then micro-scale abrasion tests performed with a slurry at a concentration which promotes grooving wear, and medium load multiple scratch tests performed with diamond indenters are completed; the results of these tests are analysed and compared to determine if there is any correlation between the two sets of results; the multiple scratch tests wear tracks are also observed to determine the wear mechanisms involved.
Chick, Kenneth M.; Gombosi, Tamas I.
1993-01-01
A numerical solution for the multiple light scattering in spherical axisymmetric geometry is applied to the simulation of images of a coma as it would appear to a near-flying satellite such as Giotto. The appearance of symmetric comas and dust jets is examined in detail; the nucleus visibility is studied; the effect of forward scattering is considered; and single and multiple scattering effects are quantified. Attention is given to simulated images of a coma with a hollow cone of dust, as predicted by dust-gas hydrodynamic modeling. The cone's appearance is very similar to the northern area of activity on Comet Halley, observed by the Giotto HMC.
Energy Technology Data Exchange (ETDEWEB)
Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics
1996-12-31
The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.
Nuallaong, Winitra; Nuallaong, Thanya; Preechadirek, Nongluck
2015-04-01
To measure academic achievement of the multiple intelligence-based learning medium via a tablet device. This is a quasi-experimental research study (non-randomized control group pretest-posttest design) in 62 grade 1 elementary students (33 males and 29 females). Thirty-one students were included in an experimental group using purposive sampling by choosing a student who had highest multiple intelligence test scores in logical-mathematic. Then, this group learned by the new learning medium via a tablet which the application matched to logical-mathematic multiple intelligence. Another 31 students were included in a control group using simple random sampling and then learning by recitation. Both groups did pre-test and post-test vocabulary. Thirty students in the experimental group and 24 students in the control group increased post-test scores (odds ratio = 8.75). Both groups made significant increasing in post-test scores. The experimental group increased 9.07 marks (95% CI 8.20-9.93) significantly higher than the control group which increased 4.39 marks (95% CI 3.06-5.72) (t = -6.032, df = 51.481, p multiple intelligence-based learning medium via a tablet or recitation can contribute academic achievement, learningfrom the new medium contributed more achievement than recitation. The new learning medium group had higher post-test scores 8.75 times than the recitation group. Therefore, the new learning medium is more effective than the traditional recitation in terms of academic achievement. This study has limitations because samples came from the same school. However, the previous study in Thailand did notfind a logical-mathematical multiple intelligence difference among schools. In the future, long-term research to find how the new learning medium affects knowledge retention will support the advantage for life-long learning.
Coulomb interaction in multiple scattering theory. [Kerman-McManus-Thaler and Watson theories
Energy Technology Data Exchange (ETDEWEB)
Ray, L.; Hoffmann, G.W.; Thaler, R.M.
1980-10-01
The treatment of the Coulomb interaction in the multiple scattering theories of Kerman-McManus-Thaler and Watson is examined in detail. By neglecting virtual Coulomb excitations, the lowest order Coulomb term in the Watson optical potential is shown to be a convolution of the point Coulomb interaction with the distributed nuclear charge, while the equivalent Kerman-McManus-Thaler Coulomb potential is obtained from an averaged, single-particle Coulombic T matrix. The Kerman-McManus-Thaler Coulomb potential is expressed as the Watson Coulomb term plus additional Coulomb-nuclear and Coulomb-Coulomb cross terms, and the omission of the extra terms in usual Kerman-McManus-Thaler applications leads to negative infinite total reaction cross section predictions and incorrect pure Coulomb scattering limits. Approximations are presented which eliminate these anomalies. Using the two-potential formula, the full projectile-nucleus T matrix is separated into two terms, one resulting from the distributed nuclear charge and the other being a Coulomb distorted nuclear T matrix. It is shown that the error resulting from the omission of the Kerman-McManus-Thaler Coulomb terms is effectively removed when the pure Coulomb T matrix in Kerman-McManus-Thaler is replaced by the analogous quantity in the Watson approach. Using the various approximations, theoretical angular distributions are obtained for 800 MeV p+/sup 208/Pb elastic scattering and compared with experimental data.
Neural Network Emulation of the Integral Equation Model with Multiple Scattering
Directory of Open Access Journals (Sweden)
Luca Pulvirenti
2009-10-01
Full Text Available The Integral Equation Model with multiple scattering (IEMM represents a well-established method that provides a theoretical framework for the scattering of electromagnetic waves from rough surfaces. A critical aspect is the long computational time required to run such a complex model. To deal with this problem, a neural network technique is proposed in this work. In particular, we have adopted neural networks to reproduce the backscattering coefficients predicted by IEMM at L- and C-bands, thus making reference to presently operative satellite radar sensors, i.e., that aboard ERS-2, ASAR on board ENVISAT (C-band, and PALSAR aboard ALOS (L-band. The neural network-based model has been designed for radar observations of both flat and tilted surfaces, in order to make it applicable for hilly terrains too. The assessment of the proposed approach has been carried out by comparing neural network-derived backscattering coefficients with IEMM-derived ones. Different databases with respect to those employed to train the networks have been used for this purpose. The outcomes seem to prove the feasibility of relying on a neural network approach to efficiently and reliably approximate an electromagnetic model of surface scattering.
A MULTIPLE SCATTERING POLARIZED RADIATIVE TRANSFER MODEL: APPLICATION TO HD 189733b
Energy Technology Data Exchange (ETDEWEB)
Kopparla, Pushkar; Yung, Yuk L. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA (United States); Natraj, Vijay; Swain, Mark R. [Jet Propulsion Laboratory (NASA-JPL), Pasadena, CA (United States); Zhang, Xi [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ (United States); Wiktorowicz, Sloane J., E-mail: pkk@gps.caltech.edu [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States)
2016-01-20
We present a multiple scattering vector radiative transfer model that produces disk integrated, full phase polarized light curves for reflected light from an exoplanetary atmosphere. We validate our model against results from published analytical and computational models and discuss a small number of cases relevant to the existing and possible near-future observations of the exoplanet HD 189733b. HD 189733b is arguably the most well observed exoplanet to date and the only exoplanet to be observed in polarized light, yet it is debated if the planet’s atmosphere is cloudy or clear. We model reflected light from clear atmospheres with Rayleigh scattering, and cloudy or hazy atmospheres with Mie and fractal aggregate particles. We show that clear and cloudy atmospheres have large differences in polarized light as compared to simple flux measurements, though existing observations are insufficient to make this distinction. Futhermore, we show that atmospheres that are spatially inhomogeneous, such as being partially covered by clouds or hazes, exhibit larger contrasts in polarized light when compared to clear atmospheres. This effect can potentially be used to identify patchy clouds in exoplanets. Given a set of full phase polarimetric measurements, this model can constrain the geometric albedo, properties of scattering particles in the atmosphere, and the longitude of the ascending node of the orbit. The model is used to interpret new polarimetric observations of HD 189733b in a companion paper.
Redistribution of light frequency by multiple scattering in a resonant atomic vapor
Carvalho, J C de A; Oriá, M; Chevrollier, M; de Silans, T Passerat
2015-01-01
The propagation of light in a resonant atomic vapor can \\textit{a priori} be thought of as a multiple scattering process, in which each scattering event redistributes both the direction and the frequency of the photons. Particularly, the frequency redistribution may result in L\\'evy flights of photons, directly affecting the transport properties of light in a resonant atomic vapor and turning this propagation into a superdifusion process. Here, we report on a Monte-Carlo simulation developed to study the evolution of the spectrum of the light in a resonant thermal vapor. We observe the gradual change of the spectrum and its convergence towards a regime of Complete Frequency Redistribution as the number of scattering events increases. We also analyse the probability density function of the step length of photons between emissions and reabsorptions in the vapor, which governs the statistics of the light diffusion. We observe two different regime in the light transport: superdiffusive when the vapor is excited n...
High-definition projection screen based on multiple light scattering technique
Suzuki, Hiromasa; Okumura, Takamitsu; Tagaya, Akihiro; Higuchi, Eizaburo; Koike, Yasuhiro
2004-05-01
A novel rear projection screen (Blue Ocean screen, Nitto Jyushi Kogyo, Co., Ltd.) has been developed. Blue Ocean screen is a single polymer plate requiring no lens element. The projected image is formed on the screen surface by the multiple light scattering. An image light is multiply scattered and is converted into homogeneous light distribution efficiently due to the internal particles of micron order dispersed in the acrylic polymer matrix. An ambient light is reduced by the dye molecules doped in the polymer and the anti-reflective coating on the screen surface. The condition of the particles and the concentration of the dye molecules have been optimized by the ray tracing simulation program based on Mie scattering theory using a Monte Carlo method. The screen containing the particles of optimum condition exhibits the wide viewing angle, the well-controlled color balance, and the high sharpness level at the same time. The contrast level of the projected image in ambient light is improved by controlling the concentration of the dye molecules. This paper describes the optimization obtained theoretically and experimentally, and demonstrates the advantage of Blue Ocean screen.
Cerussi, Albert E.; Gratton, Enrico; Fantini, Sergio
1999-07-01
Over the past few years, there has been significant research activity devoted to the application of fluorescence spectroscopy to strongly scattering media, where photons propagate diffusely. Much of this activity focused on fluorescence as a source of contrast enhancement in optical tomography. Our efforts have emphasized the quantitative recovery of fluorescence parameters for spectroscopy. Using a frequency-domain diffusion-based model, we have successfully recovered the lifetime, the absolute quantum yield, the fluorophore concentration, and the emission spectrum of the fluorophore, as well as the absorption and the reduced scattering coefficients at the emission wavelength of the medium in different measurements. In this contribution, we present a sensitive monitor of the binding between ethidium bromide and bovine cells in fresh milk. The spectroscopic contrast was the approximately tenfold increase in the ethidium bromide lifetime upon binding to DNA. The measurement clearly demonstrated that we could quantitatively measure the density of cells in the milk, which is an application vital to the tremendous economic burden of bovine subclinical mastitis detection. Furthermore, we may in principle use the spirit of this technique as a quantitative monitor of the binding of fluorescent drugs inside tissues. This is a first step towards lifetime spectroscopy in tissues.
Energy dependence of the charged multiplicity in deep inelastic scattering at HERA
Energy Technology Data Exchange (ETDEWEB)
Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)
2008-03-15
The charged multiplicity distributions and the mean charged multiplicity have been investigated in inclusive neutral current deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 38.6 pb{sup -1}. The measurements were performed in the current region of the Breit frame, as well as in the current fragmentation region of the hadronic centre-of-mass frame. The KNO-scaling properties of the data were investigated and the energy dependence was studied using different energy scales. The data are compared to results obtained in e{sup +}e{sup -} collisions and to previous DIS measurements as well as to leading-logarithm parton-shower Monte Carlo predictions. (orig.)
Multiple solutions to dense systems in radar scattering using a preconditioned block GMRES solver
Energy Technology Data Exchange (ETDEWEB)
Boyse, W.E. [Advanced Software Resources, Inc., Santa Clara, CA (United States)
1996-12-31
Multiple right-hand sides occur in radar scattering calculations in the computation of the simulated radar return from a body at a large number of angles. Each desired angle requires a right-hand side vector to be computed and the solution generated. These right-hand sides are naturally smooth functions of the angle parameters and this property is utilized in a novel way to compute solutions an order of magnitude faster than LINPACK The modeling technique addressed is the Method of Moments (MOM), i.e. a boundary element method for time harmonic Maxwell`s equations. Discretization by this method produces general complex dense systems of rank 100`s to 100,000`s. The usual way to produce the required multiple solutions is via LU factorization and solution routines such as found in LINPACK. Our method uses the block GMRES iterative method to directly iterate a subset of the desired solutions to convergence.
A triple axis double crystal multiple reflection camera for ultra small angle X-ray scattering
Lambard, Jacques; Lesieur, Pierre; Zemb, Thomas
1992-06-01
To extend the domain of small angle X-ray scattering requires multiple reflection crystals to collimate the beam. A double crystal, triple axis X-ray camera using multiple reflection channel cut crystals is described. Procedures for measuring the desmeared scattering cross-section on absolute scale are described as well as the measurement from several typical samples : fibrils of collagen, 0.3 μm diameter silica spheres, 0.16 μm diameter interacting latex spheres, porous lignite coal, liquid crystals in a surfactant-water system, colloidal crystal of 0.32 μm diameter silica spheres. L'extension du domaine de diffusion des rayons-X vers les petits angles demande l'emploi de cristaux à réflexions multiples pour collimater le faisceau. Nous décrivons une caméra à rayons-X à trois axes où les réflexions multiples sont réalisées dans deux cristaux à gorge. Nous donnons ensuite les procédures de déconvolution pour obtenir la section efficace de diffusion en échelle absolue, ainsi que les résultats des mesures effectuées avec plusieurs échantillons typiques : fibres de collagène, sphères de silice de 0,3 μm de diamètre, sphères de latex de 0,16 μm de diamètre en interaction, charbon lignite poreux, cristaux liquides formés dans un système eau-tensioactif, solution colloïdale de sphères de silice de 0,32 μm de diamètre.
Green's function multiple-scattering theory with a truncated basis set: An augmented-KKR formalism
Alam, Aftab; Khan, Suffian N.; Smirnov, A. V.; Nicholson, D. M.; Johnson, Duane D.
2014-11-01
The Korringa-Kohn-Rostoker (KKR) Green's function, multiple-scattering theory is an efficient site-centered, electronic-structure technique for addressing an assembly of N scatterers. Wave functions are expanded in a spherical-wave basis on each scattering center and indexed up to a maximum orbital and azimuthal number Lmax=(l,mmax), while scattering matrices, which determine spectral properties, are truncated at Lt r=(l,mt r) where phase shifts δl >ltr are negligible. Historically, Lmax is set equal to Lt r, which is correct for large enough Lmax but not computationally expedient; a better procedure retains higher-order (free-electron and single-site) contributions for Lmax>Lt r with δl >ltr set to zero [X.-G. Zhang and W. H. Butler, Phys. Rev. B 46, 7433 (1992), 10.1103/PhysRevB.46.7433]. We present a numerically efficient and accurate augmented-KKR Green's function formalism that solves the KKR equations by exact matrix inversion [R3 process with rank N (ltr+1 ) 2 ] and includes higher-L contributions via linear algebra [R2 process with rank N (lmax+1) 2 ]. The augmented-KKR approach yields properly normalized wave functions, numerically cheaper basis-set convergence, and a total charge density and electron count that agrees with Lloyd's formula. We apply our formalism to fcc Cu, bcc Fe, and L 1 0 CoPt and present the numerical results for accuracy and for the convergence of the total energies, Fermi energies, and magnetic moments versus Lmax for a given Lt r.
The Over-Barrier Resonant States and Multi-Channel Scattering in Multiple Quantum Wells
Directory of Open Access Journals (Sweden)
A Polupanov
2016-09-01
Full Text Available We demonstrate an explicit numerical method for accurate calculation of the scattering matrix and its poles, and apply this method to describe the multi-channel scattering in the multiple quantum-wells structures. The S-matrix is continued analytically to the unphysical region of complex energy values. Results of calculations show that there exist one or more S-matrix poles, corresponding to the over-barrier resonant states critical for the effect of the absolute reflection of holes in the energy range where only the heavy ones may propagate over barriers in a structure. Light- and heavy-hole states are described by the Luttinger Hamiltonian matrix. In contrast to the single quantum-well case, at some parameters of a multiple quantum-wells structure the number of S-matrix poles may exceed that of the absolute reflection peaks, and at different values of parameters the absolute reflection peak corresponds to different resonant states. The imaginary parts of the S-matrix poles and hence the lifetimes of resonant states as well as the widths of resonant peaks of absolute reflection depend drastically on the quantum-well potential depth. In the case of shallow quantum wells there is in fact a long-living over-barrier resonant hole state.
Agueny, H.; Makhoute, A.; Tökési, K.; Dubois, A.; Hansen, J. P.
2017-09-01
We theoretically investigate electron emission process from a dimer generated by swift highly charged ions. The process under consideration is dealt with a non-perturbative approach by solving the time-dependent Schrödinger equation on a two-dimensional spatial grid. Numerical calculations show rich structures related to the multiple scattering paths of the electron prior to emission. This manifests by the emergence of additional oscillations with high-frequency superimposed on the Young-type oscillatory structure in the observed electron-ejected spectrum. This is not the case when calculations are performed based on the superposition principle, in which the final wave function is just a coherent sum of component wave functions described the electron emission from two-independent atoms. Within this assumption, only a direct electron emission process is taken into account. We find that contributions arising from these multiple scattering paths modify the dynamic electron emission process, and therefore, show the incorrect applicability of the above-mentioned principle, in concordance with the recent findings based on a simple three-slit interference experiment, reported in Sawant et al. (2014).
Wilson, S. J.; Wan, F. S.
1987-10-01
A variation of the moment method of Wilson and Sen (1986) is used to solve the radiative transfer problem in an anisotropic scattering plane-parallel medium with an arbitrary space-dependent albedo, omega (x). Considering the case of both forward and backward scattering, the reflectance and transmission functions for linear and quadratic variation of omega(x) are given for isotropic incidence of unit intensity. The exit distribution of radiation for a linear variation of omega(x) is also given for both isotropic and normal incidence of intensity. Results from the present delta approximation method are in good agreement with those of Cengel and Ozisik (1985).
Mitri, F. G.
2017-08-01
The multiple scattering effects occurring between two scatterers are described based upon the multipole expansion formalism as well as the addition theorem of cylindrical wave functions. An original approach is presented in which an effective incident acoustic field on a particular object, which includes both the primary and re-scattered waves from the other particle is determined first, and then used with the scattered field to derive closed-form analytical expressions for the inherent (i.e. intrinsic) cross-sections based on the far-field scattering. This method does not introduce any approximation in the calculation of the intrinsic cross-sections since the procedure is reduced to the one-body problem. The mathematical expressions for the intrinsic cross-sections are formulated in partial-wave series expansions (PWSEs) in cylindrical coordinates involving the angle of incidence, the addition theorem for the cylindrical wave functions, and the expansion coefficients of the scatterers. Numerical examples illustrate the analysis for two rigid circular cylindrical cross-sections with different radii immersed in a non-viscous fluid. Computations for the dimensionless extrinsic and intrinsic extinction cross-section factors are evaluated with particular emphasis on varying the angle of incidence, the interparticle distance, as well as the sizes of the particles. A symmetric behavior is observed for the dimensionless extrinsic extinction cross-section, while asymmetry arises for the intrinsic extinction cross-section of each particle with respect to the angle of incidence. The present analysis provides a complete analytical and computational method for the prediction of the intrinsic (local) scattering, absorption and extinction cross-sections in the multiple acoustic scatterings of plane progressive waves of arbitrary incidence by a pair of scatterers. The results and computational analyses can be used as a priori information for future applications to guide the
Spectrometer for Particle Characterization With a New Multiple-Scattering Theory Project
National Aeronautics and Space Administration — There are two major commercial types of light-scattering particle size analyzers: Static Light Scattering and Dynamic Light Scattering. They are expensive, delicate,...
Yu, Mei Ping; Han, Yi Ping; Cui, Zhi Wei; Chen, An Tao
2017-07-01
This study investigates the electromagnetic scattering of a high-order Bessel vortex beam by multiple dielectric particles of arbitrary shape based on the surface integral equation (SIE) method. In Cartesian coordinates, the mathematical formulas are given for characterizing the electromagnetic field components of an arbitrarily incident high-order Bessel vortex beam. By using the SIE, a numerical scheme is formulated to find solutions for characterizing the electromagnetic scattering by multiple homogeneous particles of arbitrary shape and a home-made FORTRAN program is written. The presented theoretical derivations as well as the home-made program are validated by comparing to the scattering results of a Zero-Order Bessel Beam by the Generalized Lorenz-Mie theory. From our simulations, the beam's order, half-cone angles, and the ways of particles' arrangement have a great influence upon the differential scattering cross section (DSCS) for multiple particles. Furthermore, for a better understanding of the scattering characteristic in three dimension (3-D) space, the 3-D distribution of the DSCS for different cases is presented. It is anticipated that these results can be helpful to understand the scattering mechanisms of a high-order Bessel vortex beam on multiple dielectric particles of arbitrary shape.
Track reconstruction for the Mu3e experiment based on a novel Multiple Scattering fit
Directory of Open Access Journals (Sweden)
Kozlinskiy Alexandr
2017-01-01
Full Text Available The Mu3e experiment is designed to search for the lepton flavor violating decay μ+ → e+e+e−. The aim of the experiment is to reach a branching ratio sensitivity of 10−16. In a first phase the experiment will be performed at an existing beam line at the Paul-Scherrer Institute (Switzerland providing 108 muons per second, which will allow to reach a sensitivity of 2 · 10−15. The muons with a momentum of about 28 MeV/c are stopped and decay at rest on a target. The decay products (positrons and electrons with energies below 53MeV are measured by a tracking detector consisting of two double layers of 50 μm thin silicon pixel sensors. The high granularity of the pixel detector with a pixel size of 80 μm × 80 μm allows for a precise track reconstruction in the high multiplicity environment of the Mu3e experiment, reaching 100 tracks per reconstruction frame of 50 ns in the final phase of the experiment. To deal with such high rates and combinatorics, the Mu3e track reconstruction uses a novel fit algorithm that in the simplest case takes into account only the multiple scattering, which allows for a fast online tracking on a GPU based filter farm. An implementation of the 3-dimensional multiple scattering fit based on hit triplets is described. The extension of the fit that takes into account energy losses and pixel size is used for offline track reconstruction. The algorithm and performance of the offline track reconstruction based on a full Geant4 simulation of the Mu3e detector are presented.
Grzela, Grzegorz; Rivas, Jaime Gómez
2013-01-01
We present an experimental and theoretical study of the angle- and polarization-dependent light extinction in random arrays of polydisperse semiconductor nanowires epitaxially grown on substrates. The specular reflectance is described by averaging the scattering properties of individual nanowires obtained from Lorenz-Mie theory over the diameter distribution. The complex effective refractive index describing the propagation and attenuation of the coherent beam scattered in forward direction is determined in the independent scattering approximation and used to calculate the angle- and polarization-dependent reflectance. Our measurements demonstrate the highly anisotropic scattering in ensembles of aligned nanowires.
Measurement of Hadron Multiplicities in Deep Inelastic Muon-Nucleon Scattering
du Fresne von Hohenesche, Nicolas
2016-06-02
In deep-inelastic muon-nucleon scattering, a single quark can be ejected out of the nucleon by the absorption of a high-energy photon. Such a free isolated quark has never been observed in nature. In quantum chromodynamics (QCD), coloured objects, such as a single quark, create additional quark anti-quark pairs out of the colour field and the final state comprises a jet of hadrons. The hadronisation process can be described by fragmentation functions D_q^h, the probability that a quark with the flavour q turns into a hadron of the type h. Similar to the parton distribution function, the fragmentation functions are fundamental, universal and process-independent quantities. The fragmentation functions are measured with the COM- PASS spectrometer in muon-nucleon scattering. The observables are the hadron multiplicities M_h. The COMPASS experiment consists of a two-stage magnetic spectrometer located at the M2 beam line of the Super Proton Synchrotron at CERN and uses a polarised muon beam on a nuclear fixed targ...
Khromova, Anastasiya
2010-01-01
A Monte Carlo program based on a three dimensional vector approach was developed to model multiple refractive scattering of X-ray photons in objects with a fine structure. A particular interest was paid to the investigation of lung tissue. Alveoli are low contrast and low absorbing structures. Hence, they are not visible in the conventional radiography which is based on the changes in the absorption arising from density differences and from variation in the thickness and composition of the object. Another possibility to image fine structure objects is to use the phase imaging techniques. As known, the phase change constant delta at low energies (15-30 keV) is 1000 times larger than the absorption constant beta. The Diffraction Enhance Imaging (DEI) technique is one of the recent phase sensitive techniques based on the use of an analyzer crystal placed between the sample and the detector.
Multiple scattering of low energy ions in matter: Influence of energy loss and interaction potential
Energy Technology Data Exchange (ETDEWEB)
Mekhtiche, A. [Laboratoire SNIRM, Faculté de Physique, Université des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32 El Alia, Bab Ezzouar, Algiers (Algeria); Faculté des Sciences et de la Technologie, Université Yahia Farès de Médéa (Algeria); Khalal-Kouache, K., E-mail: kkouache@yahoo.fr [Laboratoire SNIRM, Faculté de Physique, Université des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32 El Alia, Bab Ezzouar, Algiers (Algeria)
2015-07-01
In this paper, the effect of inelastic energy loss and interaction potential on transmitted ions at low energy is studied. For this purpose, angular distributions of slow He{sup +} ions transmitted through thin Ag films are calculated using the theory of multiple scattering. Thin films (20–50 Å at 2 keV and 50–200 Å at 10 keV) are considered so that the total path length of transmitted ions can be approximated by the value of the target thickness in this calculation. The corresponding values of the relative energy loss ΔE/E are comprised between 0.04 and 0.17. We show that even if low values of the thickness are considered, the total energy loss of ions in the target should be included in the calculation. These calculated angular distributions are also influenced by the potential used to describe the interaction between the incident ion and the target atom.
Multiple scattering and the Rehr-Albers-Fritzsche formula for the propagator matrix
Martin, P. A.
1998-11-01
The propagator matrix is one ingredient in exact theories of multiple scattering. It occurs in the addition theorem (or translation formula) for expanding a spherical outgoing multipole, singular at one point, in terms of regular spherical solutions about another point. It also occurs in the two-centre expansion of the free-space Green's function (or free-particle propagator). Many methods have been devised for computing the propagator matrix, but one of the most efficient, numerically, is based on a formula obtained in 1990 by Rehr and Albers and by Fritzsche. A clear derivation of this formula is given. The formula is also simplified, leading to an expansion in inverse powers of kb, where k is the wavenumber and b is the spacing. This leads to consistent approximations, which are asymptotic as 0305-4470/31/44/016/img1.
Liu, Z Z; Xiao, J J
2015-01-01
We study the optical properties associated to both the polariton gap and the Bragg gap in periodic resonator-waveguide coupled system, based on the temporal coupled mode theory and the transfer matrix method. By the complex band and the transmission spectrum, it is feasible to tune the interaction between multiple Bragg scattering and the local resonance, which may give rise to analogous phenomena of electromagnetically induced transparency (EIT). We further design a plasmonic slot waveguide side-coupled with local plasmonic resonator to demonstrate the EIT-like effects in the near-infared band. Numerical calculations show that realistic amount of metal Joule loss may destroy the interference and the total absorption is enhanced in the transparency windwo due to the near zero group velocity of the guiding wave.
Momentum measurement by the Multiple Coulomb Scattering method in the OPERA lead emulsion target
Agafonova, N.; Altinok, O.; Anokhina, A.; Aoki, S.; Ariga, A.; Ariga, T.; Autiero, D.; Badertscher, A.; Bagulya, A.; Ben Dhahbi, A.; Bertolin, A.; Besnier, M.; Bozza, C.; Brugiere, T.; Brugnera, R.; Brunet, F.; Brunetti, G.; Buontempo, S.; Cazes, A.; Chaussard, L.; Chernyavskiy, M.; Chiarella, V.; Chukanov, A.; D'Ambrosio, N.; Dal Corso, F.; De Lellis, G.; del Amo Sanchez, P.; Declais, Y.; De Serio, M.; Di Capua, F.; Di Crescenzo, A.; Di Ferdinando, D.; Di Marco, N.; Dmitrievski, S.; Dracos, M.; Duchesneau, D.; Dusini, S.; Dzhatdoev, T.; Ebert, J.; Egorov, O.; Enikeev, R.; Ereditato, A.; Esposito, L.S.; Favier, J.; Ferber, T.; Fini, R.A.; Frekers, D.; Fukuda, T.; Garfagnini, A.; Giacomelli, G.; Giorgini, M.; Gollnitz, C.; Goldberg, J.; Golubkov, D.; Goncharova, L.; Gornushkin, Y.; Grella, G.; Grianti, F.; Guler, A.M.; Gustavino, C.; Hagner, C.; Hamada, K.; Hara, T.; Hierholzer, M.; Hollnagel, A.; Hoshino, K.; Ieva, M.; Ishida, H.; Jakovcic, K.; Jollet, C.; Juget, F.; Kamiscioglu, M.; Kazuyama, K.; Kim, S.H.; Kimura, M.; Kitagawa, N.; Klicek, B.; Knuesel, J.; Kodama, K.; Komatsu, M.; Kose, U.; Kreslo, I.; Kubota, H.; Lazzaro, C.; Lenkeit, J.; Lippi, I.; Ljubicic, A.; Longhin, A.; Loverre, P.; Lutter, G.; Malgin, A.; Mandrioli, G.; Manai, K.; Marteau, J.; Matsuo, T.; Matveev, V.; Mauri, N.; Medinaceli, E.; Meisel, F.; Meregaglia, A.; Migliozzi, P.; Mikado, S.; Miyamoto, S.; Monacelli, P.; Morishima, K.; Moser, U.; Muciaccia, M.T.; Naganawa, N.; Naka, T.; Nakamura, M.; Nakano, T.; Naumov, D.; Nikitina, V.; Niwa, K.; Nonoyama, Y.; Ogawa, S.; Okateva, N.; Olshevskiy, A.; Paniccia, M.; Paoloni, A.; Park, B.D.; Park, I.G.; Pastore, A.; Patrizii, L.; Pennacchio, E.; Pessard, H.; Pretzl, K.; Pilipenko, V.; Pistillo, C.; Polukhina, N.; Pozzato, M.; Pupilli, F.; Rescigno, R.; Roganova, T.; Rokujo, H.; Romano, G.; Rosa, G.; Rostovtseva, I.; Rubbia, A.; Russo, A.; Ryasny, V.; Ryazhskaya, O.; Sato, O.; Sato, Y.; Schembri, A.; Schmidt-Parzefall, W.; Schroeder, H.; Scotto Lavina, L.; Sheshukov, A.; Shibuya, H.; Shoziyoev, G.; Simone, S.; Sioli, M.; Sirignano, C.; Sirri, G.; Song, J.S.; Spinetti, M.; Stanco, L.; Starkov, N.; Stipcevic, M.; Strauss, T.; Strolin, P.; Takahashi, S.; Tenti, M.; Terranova, F.; Tezuka, I.; Tioukov, V.; Tolun, P.; Trabelsi, A.; Tran, T.; Tufanli, S.; Vilain, P.; Vladimirov, M.; Votano, L.; Vuilleumier, J.L.; Wilquet, G.; Wonsak, B.; Yakushev, V.; Yoon, C.S.; Yoshioka, T.; Yoshida, J.; Zaitsev, Y.; Zemskova, S.; Zghiche, A.; Zimmermann, R.
2012-01-01
A new method of momentum measurement of charged particles through Multiple Coulomb Scattering (MCS) in the OPERA lead emulsion target is presented. It is based on precise measurements of track angular deviations performed thanks to the very high resolution of nuclear emulsions. The algorithm has been tested with Monte Carlo (MC) pions. The results are found to describe within the expected uncertainties the data obtained from test beams. We also report a comparison of muon momenta evaluated through MCS in the OPERA lead emulsion target with those determined by the electronic detectors for neutrino charged current interaction events. The two independent measurements agree within the experimental uncertainties, and the results validate the algorithm developed for the emulsion detector of OPERA.
Multiple Scattering of Seismic Waves from Ensembles of Upwardly Lossy Thin Flux Tubes
Hanson, Chris S
2015-01-01
Our previous semi-analytic treatment of f- and p-mode multiple scattering from ensembles of thin flux tubes (Hanson and Cally, Astrophys. J. 781, 125; 791, 129, 2014) is extended by allowing both sausage and kink waves to freely escape at the top of the model using a radiative boundary condition there. As expected, this additional avenue of escape, supplementing downward loss into the deep solar interior, results in substantially greater absorption of incident f- and p-modes. However, less intuitively, it also yields mildly to substantially smaller phase shifts in waves emerging from the ensemble. This may have implications for the interpretation of seismic data for solar plage regions, and in particular their small measured phase shifts.
Directory of Open Access Journals (Sweden)
Qingbo Li
2013-01-01
Full Text Available In order to improve the predictive accuracy of human blood glucose quantitative analysis model with fourier transform infrared (FT-IR spectroscopy, this paper uses a method named improved extended multiplicative scatter correction (Im-EMSC, which can effectively eliminate the scattering effects caused by human body strong scattering. The principal components of the differential spectra are used instead of the pure spectra of the analytes in this algorithm. Calibrate the unwanted physical characteristic through the shape of the curve of principal components, and extract the original glucose concentration information. Im-EMSC can efficiently remove most of the pathlength difference and baseline shift influences. Firstly, Im-EMSC is used as a preprocessing method, and then partial least squares (PLS regression method is adopted to establish a quantitative analysis model. In this paper, the result of Im-EMSC is compared with those popular scattering correction algorithms of multiplicative scatter correction (MSC and extended multiplicative scatter correction (EMSC preprocessing methods. Experimental results show that the prediction accuracy has been greatly improved with Im-EMSC method, which is helpful for human noninvasive glucose concentration detection technology.
Numerical Simulations of Single and Multiple Scattering by Fractal Ice Clusters
Dlugach, Janna M.; Mishchenko, Michael I.; Mackowski, Daniel W.
2011-01-01
We consider the scattering model in the form of a vertically and horizontally homogeneous particulate slab of an arbitrary optical thickness composed of widely separated fractal aggregates built of small spherical ice monomers. The aggregates are generated by applying three different approaches, including simulated cluster-cluster aggregation (CCA) and diffusion-limited aggregation (DLA) procedures. Having in mind radar remote-sensing applications, we report and analyze the results of computations of the backscattering circular polarization ratio obtained using efficient superposition T-matrix and vector radiative-transfer codes. The computations have been performed at a wavelength of 12.6 cm for fractal aggregates with the following characteristics: monomer refractive index m=1.78+i0.003, monomer radius r=1 cm, monomer packing density p=0.2, overall aggregate radii R in the range 4fractal dimensions D(sub f) 2.5 and 3. We show that for aggregates generated with simulated CCA and DLA procedures, the respective values of the backscattering circular polarization ratio differ weakly for D(sub f) 2.5, but the differences can increase somewhat for D(sub f)3, especially in case of an optically semi-infinite medium. For aggregates with a spheroidal overall shape, the dependence of the circular polarization ratio on the cluster morphology can be quite significant and increases with increasing the aspect ratio of the circumscribing spheroid.
Superluminal two-color light in a multiple Raman gain medium
Kudriašov, V.
2014-09-17
We investigate theoretically the formation of two-component light with superluminal group velocity in a medium controlled by four Raman pump fields. In such an optical scheme only a particular combination of the probe fields is coupled to the matter and exhibits superluminal propagation; the orthogonal combination is uncoupled. The individual probe fields do not have a definite group velocity in the medium. Calculations demonstrate that this superluminal component experiences an envelope advancement in the medium with respect to the propagation in vacuum.
Elastic Scattering of Low Energy Pions by Nuclei and the In-Medium Isovector πN Amplitude
Friedman, E.; Bauer, M.; Breitschopf, J.; Clement, H.; Denz, H.; Doroshkevich, E.; Erhardt, A.; Hofman, G. J.; Kritchman, S.; Meier, R.; Wagner, G. J.; Yaari, G.
2006-07-01
Measurements of elastic scattering of 21.5 MeV π± by Si, Ca, Ni and Zr were made using a single arm magnetic spectrometer and absolute calibration was made by parallel measurements of Coulomb scattering of muons. Optical model fits to the data reveal the `anomalous' s-wave repulsion known from pionic atoms. Introducing a chiral-motivated density dependence of the isovector scattering amplitude, and considering the energy dependence of the free πN interaction greatly improve fits to the data and remove the `anomaly'.
Directory of Open Access Journals (Sweden)
Silvio Lopes Teixeira
2009-10-01
Full Text Available Lately it has been observed a great interest in the research area of plant tissue culture in discovering new alternatives leading to cost reduction of the plants produced in commercial laboratories, in order to turn this alternative of plant propagation more economical. A potentially promising alternative for this reduction of costs, but which has not been receiving the due attention, is the possibility of substituting the autoclaving technique to a more economical one. With this purpose, two tests were carried out, using a new protocol of medium preparation, which consisted of the chemical sterilization of all the utensils used in the preparation and packaging of the culture medium as well, associated to the addition of the sterilizing agent to the medium, in different concentrations. The objective of the first test was to observe the influence of different concentrations of NaClO added to the culture medium, on its sterilization. The second test aimed at verifying the reaction of the Eucalyptus pellita tissues to different concentrations of NaClO in the culture medium. The addition of NaClO to the culture medium, equal or higher than 0.0005% in the fist test and of 0.005% in the second one, allowed complete sterilization of the medium, without observing any damage to the Eucalyptus pellita tissues, even when they were grown on culture medium containing up to 0.009%, the maximum concentration tried. The results showed the viability of eliminating the autoclave for the sterilization of culture media.
Toft-Petersen, Rasmus; Groitl, Felix; Kure, Mathias; Lim, Joshua; Čermák, Petr; Alimov, Svyatoslav; Wilpert, Thomas; Le, Manh Duc; Quintero-Castro, Diana; Niedermayer, Christof; Schneidewind, Astrid; Habicht, Klaus
2016-09-01
A thorough experimental characterization of a multiplexing backend with multiple energy analysis on a cold-neutron triple axis spectrometer (cTAS) is presented. The prototype employs two angular segments (2 θ -segments) each containing five vertically scattering analyzers (energy channels), which simultaneously probe an energy transfer range of 2 meV at the corresponding two scattering angles. The feasibility and strength of such a vertically scattering multiple energy analysis setup is clearly demonstrated. It is shown, that the energy resolution near the elastic line is comparable to the energy resolution of a standard cTAS. The dispersion relation of the antiferromagnetic excitations in MnF2 has been mapped out by performing constant energy transfer maps. These results show that the tested setup is virtually spurion free. In addition, focusing effects due to (mis)matching of the instrumental resolution ellipsoid to the excitation branch are clearly evident.
Directory of Open Access Journals (Sweden)
Shen-Yung Wang
2015-03-01
Conclusions: Medium-sized hepatocellular carcinoma can be effectively ablated with monopolar radiofrequency ablation by either single-electrode overlapping ablation or a multiple-electrode switching system. Regarding mid-term treatment responses, both RFA approaches can achieve similar treatment effectiveness, local tumor progression rate, and survival probabilities. Multiple-electrode switching RFA can treat larger medium-sized HCC with comparable mid-term efficacy as smaller medium-sized HCC treated with single-electrode overlapping RFA.
DEFF Research Database (Denmark)
Toft-Petersen, Rasmus; Groitl, Felix; Kure, Mathias;
2016-01-01
A thorough experimental characterization of a multiplexing backend with multiple energy analysis on a cold-neutron triple axis spectrometer (cTAS) is presented. The prototype employs two angular segments (2 theta-segments) each containing five vertically scattering analyzers (energy channels), wh...
Tsang, Leung; Chen, Zhengxiao; Oh, Seho; Marks, Robert J., II; Chang, A. T. C.
1992-01-01
Simultaneous inversion of the three parameters was performed which included mean-grain size of ice particles in snow, snow density, and snow temperatures from five brightness temperatures. Good results for the inversion of parameters were obtained using the neural network based on the simulated data computed from the dense media radiative transfer equation that takes into account the effects of multiple scattering.
Energy Technology Data Exchange (ETDEWEB)
Kodama, K. [Aichi University of Education, Kariya (Japan); Saoulidou, N. [University of Athens (Greece); Tzanakos, G. [University of Athens (Greece); Baller, B. [Fermilab, Batavia, IL 60510 (United States); Lundberg, B. [Fermilab, Batavia, IL 60510 (United States); Rameika, R. [Fermilab, Batavia, IL 60510 (United States); Song, J.S. [Gyeongsang University, Chinju, South Korea (Korea, Republic of); Yoon, C.S. [Gyeongsang University, Chinju, South Korea (Korea, Republic of); Chung, S.H. [Gyeongsang University, Chinju, South Korea (Korea, Republic of); Aoki, S. [Kobe University, Kobe (Japan); Hara, T. [Kobe University, Kobe (Japan); Erickson, C. [University of Minnesota, MN (United States); Heller, K. [University of Minnesota, MN (United States); Schwienhorst, R. [University of Minnesota, MN (United States); Sielaff, J. [University of Minnesota, MN (United States); Trammell, J. [University of Minnesota, MN (United States); Hoshino, K. [Nagoya University, Nagoya 464 8602 (Japan); Kawada, J. [Nagoya University, Nagoya 464 8602 (Japan); Komatsu, M. [Nagoya University, Nagoya 464 8602 (Japan); Miyanishi, M. [Nagoya University, Nagoya 464 8602 (Japan); Nakamura, M. [Nagoya University, Nagoya 464 8602 (Japan); Nakano, T. [Nagoya University, Nagoya 464 8602 (Japan); Narita, K. [Nagoya University, Nagoya 464 8602 (Japan); Niwa, K. [Nagoya University, Nagoya 464 8602 (Japan); Nonaka, N. [Nagoya University, Nagoya 464 8602 (Japan); Okada, K.; Sato, O.; Toshito, T.; Miyamoto, S.; Takahashi, S. [Nagoya University, Nagoya 464 8602 (Japan); Park, B.D. [Nagoya University, Nagoya 464 8602 (Japan)]. E-mail: park@flab.phys.nagoya-u.ac.jp; Furukawa, T. [Nagoya University, Nagoya 464 8602 (Japan); Paolone, V. [University of Pittsburgh, Pittsburgh, PA 15260 (United States); Kafka, T. [Tufts University, Medford, Massachusetts 02155 (United States)
2007-04-21
We present a method of momentum measurement of charged particles using emulsion data from the DONuT experiment, and report results from the momentum analysis of secondary particles from neutrino interactions. In 578 neutrino interactions, 2338 secondary particles were analyzed and 83.2% of attempted particles were measured by multiple coulomb scattering.
Elastic scattering of low energy pions by nuclei and the in-medium isovector pi N amplitude
Friedman, E; Breitschopf, J; Clement, H; Denz, H; Doroshkevich, E; Erhardt, A; Hofman, G J; Kritchman, S; Meier, R; Wagner, G J; Yaari, G
2005-01-01
Measurements of elastic scattering of 21.5 MeV pi+ and pi- by Si, Ca, Ni and Zr were made using a single arm magnetic spectrometer. Absolute calibration was made by parallel measurements of Coulomb scattering of muons. Parameters of a pion-nucleus optical potential were obtained from fits to all eight angular distributions put together. The `anomalous' s-wave repulsion known from pionic atoms is clearly observed and could be removed by introducing a chiral-motivated density dependence of the isovector scattering amplitude, which also greatly improved the fits to the data. The empirical energy dependence of the isoscalar amplitude also improves the fits to the data but, contrary to what is found with pionic atoms, on its own is incapable of removing the anomaly.
Elastic scattering of low energy pions by nuclei and the in-medium isovector pi N amplitude
Friedman, E; Bauer, M.; Breitschopf, J.; H. Clement; Denz, H; Doroshkevich, E.; Erhardt, A.; Hofman, G. J.; Kritchman, S.; Meier, R.; Wagner, G. J.; Yaari, G
2005-01-01
Measurements of elastic scattering of 21.5 MeV pi+ and pi- by Si, Ca, Ni and Zr were made using a single arm magnetic spectrometer. Absolute calibration was made by parallel measurements of Coulomb scattering of muons. Parameters of a pion-nucleus optical potential were obtained from fits to all eight angular distributions put together. The `anomalous' s-wave repulsion known from pionic atoms is clearly observed and could be removed by introducing a chiral-motivated density dependence of the ...
Multiple parton interactions in deep inelastic ep-scattering at HERA
Energy Technology Data Exchange (ETDEWEB)
Osman, Sakar
2008-12-15
The production of jets with low transverse momenta (mini-jets) in deep inelastic electron-proton scattering is studied. The analyses uses data taken with the H1 detector at HERA during the years 1999 to 2000. The events are required to contain either at least one leading jet of P{sub T}>5 GeV (the inclusive 1-jet sample) or at least two hard jets where one of them has to be at an angle larger than 140 degrees with respect to the leading jet (inclusive 2-jet sample). Mini-jet multiplicities and their average transverse momenta are presented as a function of Q{sup 2}, in two regions of psuedo-rapidity and for two bins in the hadronic mass, W for the inclusive 1-jet sample. For the inclusive 2-jet sample the results are shown for direct and resolved photon interactions in two bins of W. The results are compared to various QCD based models. A new method for calibrating jet energy measurements up to 10 GeV has been developed and its performance has been studied. (orig.)
Velten, Andreas
2017-05-01
Light scattering is a primary obstacle to optical imaging in a variety of different environments and across many size and time scales. Scattering complicates imaging on large scales when imaging through the atmosphere when imaging from airborne or space borne platforms, through marine fog, or through fog and dust in vehicle navigation, for example in self driving cars. On smaller scales, scattering is the major obstacle when imaging through human tissue in biomedical applications. Despite the large variety of participating materials and size scales, light transport in all these environments is usually described with very similar scattering models that are defined by the same small set of parameters, including scattering and absorption length and phase function. We attempt a study of scattering and methods of imaging through scattering across different scales and media, particularly with respect to the use of time of flight information. We can show that using time of flight, in addition to spatial information, provides distinct advantages in scattering environments. By performing a comparative study of scattering across scales and media, we are able to suggest scale models for scattering environments to aid lab research. We also can transfer knowledge and methodology between different fields.
Alexeev, Pavel; Wille, Hans-Christian; Sergeev, Ilya; Herlitschke, Marcus; Leupold, Olaf; McMorrow, Desmond F; Röhlsberger, Ralf
2016-01-01
We report on the development and characterization of a medium resolution monochromator for synchrotron-based hyperfine spectroscopy at the 73 keV nuclear resonance of 193-Ir. The device provides high throughput of 6*10^8 ph/s in an energy bandwidth of 300(20) meV. We excited the nuclear resonance in 193-Ir at 73.04 keV and observed nuclear fluorescence of 193-Ir in Iridium metal. The monochromator allows for Nuclear Forward Scattering spectroscopy on Ir and its compounds.
Doronin, Alexander; Meglinski, Igor
2017-02-01
Current report considers development of a unified Monte Carlo (MC) -based computational model for simulation of propagation of Laguerre-Gaussian (LG) beams in turbid tissue-like scattering medium. With a primary goal to proof the concept of using complex light for tissue diagnosis we explore propagation of LG beams in comparison with Gaussian beams for both linear and circular polarization. MC simulations of radially and azimuthally polarized LG beams in turbid media have been performed, classic phenomena such as preservation of the orbital angular momentum, optical memory and helicity flip are observed, detailed comparison is presented and discussed.
Energy Technology Data Exchange (ETDEWEB)
Nunes, Rogerio Chaffin
2002-03-15
In this work, the system of differential equations obtained by the angular approach of the two-dimensional transport equation by the discrete ordinates method is solved through the formulation of finite elements with the objective of investigating the sensitivity of the outgoing flux of radiation with the incoming flux and the properties of absorption and scattering of the medium. The variational formulation for the system of differential equations of second order with the generalized boundary conditions of Neumann (third type) allows an easy implementation of the method of the finite elements with triangular mesh and approximation space of first order. The geometry chosen for the simulations is a circle with a non homogeneous circular form in its interior. The mapping of Dirichlet-Neumann is studied through various simulations involving the incoming flux, the outgoing flux and the properties of the medium. (author)
Yang, Shin Nan
2011-01-01
A simple heuristic argument to understand the existence of branch points in the unphysical sheet for pi-N scattering amplitude is presented. It is based on a hypothesis that the singularity structure of the pi-N scattering amplitude is a smooth varying function of the pion mass. We find that, in general, multiple poles structure of a resonance is a direct mathematical consequence when additional Riemann surface is included in the study and the two-pole structure found to correspond to the Roper resonance is a good example.
A hybrid approach to simulate multiple photon scattering in X-ray imaging
Energy Technology Data Exchange (ETDEWEB)
Freud, N. [CNDRI, Laboratory of Nondestructive Testing using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, avenue Albert Einstein, 69621 Villeurbanne Cedex (France)]. E-mail: nicolas.freud@insa-lyon.fr; Letang, J.-M. [CNDRI, Laboratory of Nondestructive Testing using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, avenue Albert Einstein, 69621 Villeurbanne Cedex (France); Babot, D. [CNDRI, Laboratory of Nondestructive Testing using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, avenue Albert Einstein, 69621 Villeurbanne Cedex (France)
2005-01-01
A hybrid simulation approach is proposed to compute the contribution of scattered radiation in X- or {gamma}-ray imaging. This approach takes advantage of the complementarity between the deterministic and probabilistic simulation methods. The proposed hybrid method consists of two stages. Firstly, a set of scattering events occurring in the inspected object is determined by means of classical Monte Carlo simulation. Secondly, this set of scattering events is used as a starting point to compute the energy imparted to the detector, with a deterministic algorithm based on a 'forced detection' scheme. For each scattering event, the probability for the scattered photon to reach each pixel of the detector is calculated using well-known physical models (form factor and incoherent scattering function approximations, in the case of Rayleigh and Compton scattering respectively). The results of the proposed hybrid approach are compared to those obtained with the Monte Carlo method alone (Geant4 code) and found to be in excellent agreement. The convergence of the results when the number of scattering events increases is studied. The proposed hybrid approach makes it possible to simulate the contribution of each type (Compton or Rayleigh) and order of scattering, separately or together, with a single PC, within reasonable computation times (from minutes to hours, depending on the number of pixels of the detector). This constitutes a substantial benefit, compared to classical simulation methods (Monte Carlo or deterministic approaches), which usually requires a parallel computing architecture to obtain comparable results.
DEFF Research Database (Denmark)
Zhao, Zhuoli; Yang, Ping; Guerrero, Josep M.
2016-01-01
In this paper, an islanded medium-voltage (MV) microgrid placed in Dongao Island is presented, which integrates renewable-energy-based distributed generations (DGs), energy storage system (ESS), and local loads. In an isolated microgrid without connection to the main grid to support the frequency...... of Zone B. Theoretical analysis, time-domain simulation and field test results under various conditions and scenarios in the Dongao Island microgrid are presented to prove the validity of the introduced control strategy....
Tedgren, Åsa Carlsson; Plamondon, Mathieu; Beaulieu, Luc
2015-07-07
The aim of this work was to investigate how dose distributions calculated with the collapsed cone (CC) algorithm depend on the size of the water phantom used in deriving the point kernel for multiple scatter. A research version of the CC algorithm equipped with a set of selectable point kernels for multiple-scatter dose that had initially been derived in water phantoms of various dimensions was used. The new point kernels were generated using EGSnrc in spherical water phantoms of radii 5 cm, 7.5 cm, 10 cm, 15 cm, 20 cm, 30 cm and 50 cm. Dose distributions derived with CC in water phantoms of different dimensions and in a CT-based clinical breast geometry were compared to Monte Carlo (MC) simulations using the Geant4-based brachytherapy specific MC code Algebra. Agreement with MC within 1% was obtained when the dimensions of the phantom used to derive the multiple-scatter kernel were similar to those of the calculation phantom. Doses are overestimated at phantom edges when kernels are derived in larger phantoms and underestimated when derived in smaller phantoms (by around 2% to 7% depending on distance from source and phantom dimensions). CC agrees well with MC in the high dose region of a breast implant and is superior to TG43 in determining skin doses for all multiple-scatter point kernel sizes. Increased agreement between CC and MC is achieved when the point kernel is comparable to breast dimensions. The investigated approximation in multiple scatter dose depends on the choice of point kernel in relation to phantom size and yields a significant fraction of the total dose only at distances of several centimeters from a source/implant which correspond to volumes of low doses. The current implementation of the CC algorithm utilizes a point kernel derived in a comparatively large (radius 20 cm) water phantom. A fixed point kernel leads to predictable behaviour of the algorithm with the worst case being a source/implant located well within a patient
Carlsson Tedgren, Åsa; Plamondon, Mathieu; Beaulieu, Luc
2015-07-01
The aim of this work was to investigate how dose distributions calculated with the collapsed cone (CC) algorithm depend on the size of the water phantom used in deriving the point kernel for multiple scatter. A research version of the CC algorithm equipped with a set of selectable point kernels for multiple-scatter dose that had initially been derived in water phantoms of various dimensions was used. The new point kernels were generated using EGSnrc in spherical water phantoms of radii 5 cm, 7.5 cm, 10 cm, 15 cm, 20 cm, 30 cm and 50 cm. Dose distributions derived with CC in water phantoms of different dimensions and in a CT-based clinical breast geometry were compared to Monte Carlo (MC) simulations using the Geant4-based brachytherapy specific MC code Algebra. Agreement with MC within 1% was obtained when the dimensions of the phantom used to derive the multiple-scatter kernel were similar to those of the calculation phantom. Doses are overestimated at phantom edges when kernels are derived in larger phantoms and underestimated when derived in smaller phantoms (by around 2% to 7% depending on distance from source and phantom dimensions). CC agrees well with MC in the high dose region of a breast implant and is superior to TG43 in determining skin doses for all multiple-scatter point kernel sizes. Increased agreement between CC and MC is achieved when the point kernel is comparable to breast dimensions. The investigated approximation in multiple scatter dose depends on the choice of point kernel in relation to phantom size and yields a significant fraction of the total dose only at distances of several centimeters from a source/implant which correspond to volumes of low doses. The current implementation of the CC algorithm utilizes a point kernel derived in a comparatively large (radius 20 cm) water phantom. A fixed point kernel leads to predictable behaviour of the algorithm with the worst case being a source/implant located well within a patient
Hong, Chang-Ki; Park, Chi Ho; Han, Joong-hee; Kwon, Jay Hyoun
2015-07-13
In order to obtain precise kinematic global positioning systems (GPS) in medium to large scale networks, the atmospheric effects from tropospheric and ionospheric delays need to be properly modeled and estimated. It is also preferable to use multiple reference stations to improve the reliability of the solutions. In this study, GPS kinematic positioning algorithms are developed for the medium to large-scale network based on the position-velocity-acceleration model. Hence, the algorithm can perform even in cases where the near-constant velocity assumption does not hold. In addition, the estimated kinematic accelerations can be used for the airborne gravimetry. The proposed algorithms are implemented using Kalman filter and are applied to the in situ airborne GPS data. The performance of the proposed algorithms is validated by analyzing and comparing the results with those from reference values. The results show that reliable and comparable solutions in both position and kinematic acceleration levels can be obtained using the proposed algorithms.
Directory of Open Access Journals (Sweden)
LAELA SARI
2005-07-01
Full Text Available Aloe vera of the Aloeaceae is originated from Canary Island (West Africa. This plant is commonly know in Indonesia and cultivated in large fields or in the house yard for many purposes, such as ornamental and medicine plant. The industries using it as the principle raw material has became more important due to the significant benefits of this plant. This study is purposed to obtain the medium optimization for leaf numbers and shoot multiplication of Aloe vera by BAP and adenine supplement. The shoot of Aloe vera was taken from green house of Biotechnology-LIPI. Shoots sterilized by clorox (sodium hypochlorite solution 35% and 20% for 30 and 15 min. until get aseptic shoot (in vitro plants. The shoot isolated from in vitro plant into MS (Murashige and Skoog medium in different concentration of BAP and adenine. The research used factorial Completely Randomized Design with two factors (BAP concentration: 0; 0.5; 1; 1.5; 2 mg/L and adenine concentration 0; 10; 20 mg/L with 5 replicates. The results obtained have showed that addition 20 mg/L adenine to MS raise the numbers of leaf. The shoot multiplication has been augmented by addition of BAP 1 mg/L and adenine 20 mg/L. The results showed that BAP has a positive role in increasing shoot multiplication rate and that adenine has a synergic effect when added together with BAP.
Energy Technology Data Exchange (ETDEWEB)
Malhotra, M. [Stanford Univ., CA (United States)
1996-12-31
Finite-element discretizations of time-harmonic acoustic wave problems in exterior domains result in large sparse systems of linear equations with complex symmetric coefficient matrices. In many situations, these matrix problems need to be solved repeatedly for different right-hand sides, but with the same coefficient matrix. For instance, multiple right-hand sides arise in radiation problems due to multiple load cases, and also in scattering problems when multiple angles of incidence of an incoming plane wave need to be considered. In this talk, we discuss the iterative solution of multiple linear systems arising in radiation and scattering problems in structural acoustics by means of a complex symmetric variant of the BL-QMR method. First, we summarize the governing partial differential equations for time-harmonic structural acoustics, the finite-element discretization of these equations, and the resulting complex symmetric matrix problem. Next, we sketch the special version of BL-QMR method that exploits complex symmetry, and we describe the preconditioners we have used in conjunction with BL-QMR. Finally, we report some typical results of our extensive numerical tests to illustrate the typical convergence behavior of BL-QMR method for multiple radiation and scattering problems in structural acoustics, to identify appropriate preconditioners for these problems, and to demonstrate the importance of deflation in block Krylov-subspace methods. Our numerical results show that the multiple systems arising in structural acoustics can be solved very efficiently with the preconditioned BL-QMR method. In fact, for multiple systems with up to 40 and more different right-hand sides we get consistent and significant speed-ups over solving the systems individually.
Kaina, Nadège; Lemoult, Fabrice; Fink, Mathias; Lerosey, Geoffroy
2015-09-03
Metamaterials, man-made composite media structured on a scale much smaller than a wavelength, offer surprising possibilities for engineering the propagation of waves. One of the most interesting of these is the ability to achieve superlensing--that is, to focus or image beyond the diffraction limit. This originates from the left-handed behavior--the property of refracting waves negatively--that is typical of negative index metamaterials. Yet reaching this goal requires the design of 'double negative' metamaterials, which act simultaneously on the permittivity and permeability in electromagnetics, or on the density and compressibility in acoustics; this generally implies the use of two different kinds of building blocks or specific particles presenting multiple overlapping resonances. Such a requirement limits the applicability of double negative metamaterials, and has, for example, hampered any demonstration of subwavelength focusing using left-handed acoustic metamaterials. Here we show that these strict conditions can be largely relaxed by relying on media that consist of only one type of single resonant unit cell. Specifically, we show with a simple yet general semi-analytical model that judiciously breaking the symmetry of a single negative metamaterial is sufficient to turn it into a double negative one. We then demonstrate that this occurs solely because of multiple scattering of waves off the metamaterial resonant elements, a phenomenon often disregarded in these media owing to their subwavelength patterning. We apply our approach to acoustics and verify through numerical simulations that it allows the realization of negative index acoustic metamaterials based on Helmholtz resonators only. Finally, we demonstrate the operation of a negative index acoustic superlens, achieving subwavelength focusing and imaging with spot width and resolution 7 and 3.5 times better than the diffraction limit, respectively. Our findings have profound implications for the
孔洞性介质地震散射波场正演模拟%Forward modeling of seismic scattered wave field of porous medium
Institute of Scientific and Technical Information of China (English)
雷蕾; 印兴耀; 张厚淼
2011-01-01
With the development of seismic exploration, conventional reflection simulation method shows limitation in processing complex porous geologic structure, thus developed scattered wave simulation aiming at heterogeneous porous media. Seismic scattered wave field of porous medium has been forwardly simulated by using integration method based on Green' s function; the effect of petrophysical parameters on scattered wave field has been analyzed. This study is of important significance to oil and gas exploration and development.%随着地震勘探的发展,在处理复杂的孔洞性地质构造时,常规反射波模拟方法出现了局限性.于是,针对孔洞性非均匀介质的散射波模拟方法发展起来.通过基于Green函数的积分方法来正演模拟孔洞性介质的地震波散射波场,了解其波场特征,分析物性参数对于孔洞性介质散射波场特征的影响,对油气的勘探开发具有十分重要的意义.
DEFF Research Database (Denmark)
Dalby, Arne Brejning
1994-01-01
A flow graph relating voltages and the forward and reflected propagation modes (¿ TEM) on multiple coupled transmission lines in an inhomogeneous dielectric medium is presented. This flow graph directy gives the different transfer functions, including S-parameters, in matrix form needed to calcul......-6]. This comparison shows, that the analysis and synthesis methods presented in [1-6] for interdigital filters to all practical purposes are accurate for frequencies below about 0.7 times the half-wave-length freuency for the lines....
Directory of Open Access Journals (Sweden)
Ömer Kavaklıoğlu
2011-01-01
Full Text Available We have presented a derivation of the asymptotic equations for transverse magnetic multiple scattering coefficients of an infinite grating of penetrable circular cylinders for obliquely incident plane electromagnetic waves. We have first deducted an “Ansatz” delineating the asymptotic behavior of the transverse magnetic multiple scattering coefficients associated with the most generalized condition of oblique incidence (Kavaklıoğlu, 2000 by exploiting Schlömilch series corresponding to the special circumstance that the grating spacing is much smaller than the wavelength of the incident electromagnetic radiation. The validity of the asymptotic equations for the aforementioned scattering coefficients has been verified by collating them with the Twersky's asymptotic equations at normal incidence. Besides, we have deduced the consequences that the asymptotic forms of the equations at oblique incidence acquired in this paper reduce to Twersky's asymptotic forms at normal incidence by expanding the generalized scattering coefficients at oblique incidence into an asymptotic series as a function of the ratio of the cylinder radius to the grating spacing.
Muon momentum measurement in ICARUS-T600 LAr-TPC via multiple scattering in few-GeV range
Antonello, M.; Baibussinov, B.; Bellini, V.; Benetti, P.; Boffelli, F.; Bubak, A.; Calligarich, E.; Centro, S.; Cervi, T.; Cesana, A.; Cieslik, K.; Cocco, A. G.; Dabrowska, A.; Dermenev, A.; Falcone, A.; Farnese, C.; Fava, A.; Ferrari, A.; Gibin, D.; Gninenko, S.; Guglielmi, A.; Haranczyk, M.; Holeczek, J.; Janik, M.; Kirsanov, M.; Kisiel, J.; Kochanek, I.; Lagoda, J.; Menegolli, A.; Meng, G.; Montanari, C.; Otwinowski, S.; Picchi, P.; Pietropaolo, F.; Plonski, P.; Rappoldi, A.; Raselli, G. L.; Rossella, M.; Rubbia, C.; Sala, P.; Scaramelli, A.; Sergiampietri, F.; Spanu, M.; Stefan, D.; Sulej, R.; Szarska, M.; Terrani, M.; Torti, M.; Tortorici, F.; Varanini, F.; Ventura, S.; Vignoli, C.; Wang, H.; Yang, X.; Zalewska, A.; Zani, A.; Zaremba, K.
2017-04-01
The measurement of muon momentum by Multiple Coulomb Scattering is a crucial ingredient to the reconstruction of νμ CC events in the ICARUS-T600 liquid argon TPC in absence of magnetic field, as in the search for sterile neutrinos at Fermilab where ICARUS will be exposed to ~ 1 GeV Booster neutrino beam. A sample of ~ 1000 stopping muons produced by charged current interactions of CNGS νμ in the surrounding rock at the INFN Gran Sasso underground Laboratory provides an ideal benchmark in the few-GeV range since their momentum can be directly and independently obtained by the calorimetric measurement. Stopping muon momentum in the 0.5-4.5 GeV/c range has been reconstructed via Multiple Coulomb Scattering with resolution ranging from 10 to 25% depending on muon energy, track length and uniformity of the electric field in the drift volume.
Institute of Scientific and Technical Information of China (English)
WU Jiuhui; WANG Yaojun; LI Taibao
2004-01-01
A kind of addition formulae for the spherical wave functions is generated by using the bicentric expansion of Green function in spherical coordinates. For an acoustical system with multiple spheres, the addition formulae permit the field expansions all referred to the center of one of the spheres, whose boundary conditions can be consequently used to study the multiple scattering easily. The two-sphere acoustical system with different boundary conditions is considered and the field scattered by each sphere can be obtained by solving an infinite set of two linear, complex, algebraic equations, whose coefficients are coupled through double sums in the spherical wave functions. Finally, the form functions of two spheres insonified by a plane wave at arbitrary angles of incidence are calculated and the addition formulae presented are validated by comparing the corresponding numerical results with those of the existing literature.
MaNN: Multiple Artificial Neural Networks for modelling the Interstellar Medium
Grassi, T; Piovan, L; Buonomo, U; Chiosi, C
2011-01-01
Modelling the complex physics of the Interstellar Medium (ISM) in the context of large-scale numerical simulations is a challenging task. A number of methods have been proposed to embed a description of the ISM into different codes. We propose a new way to achieve this task: Artificial Neural Networks (ANNs). The ANN has been trained on a pre-compiled model database, and its predictions have been compared to the expected theoretical ones, finding good agreement both in static and in dynamical tests run using the Padova Tree-SPH code \\textsc{EvoL}. A neural network can reproduce the details of the interstellar gas evolution, requiring limited computational resources. We suggest that such an algorithm can replace a real-time calculation of mass elements chemical evolution in hydrodynamical codes.
Siddique, I; Abdullwahab Bukhari, N; Perveen, K; Siddiqui, I; Anis, M
2013-09-01
An in vitro propagation system for Cassia angustifolia Vahl. has been developed. Due to the presence of sennosides, the demand of this plant has increased manyfold in global market. Multiple shoots were induced by culturing nodal explants excised from mature plants on a liquid Murashige and Skoog [8] medium supplemented with 5-100 μM of thidiazuron (TDZ) for different treatment duration (4, 8, 12 and 16 d). The optimal level of TDZ supplemented to the culture medium was 75 μM for 12 d induction period followed by subculturing in MS medium devoid of TDZ as it produced maximum regeneration frequency (87%), mean number of shoots (9.6 ± 0.33) and shoot length (4.4 ± 0.46 cm) per explant. A culture period longer than 12 d with TDZ resulted in the formation of fasciated or distorted shoots. Ex vitro rooting was achieved when the basal cut end of regenerated shoots was dipped in 200 μM indole-3-butyric acid (IBA) for half an hour followed by their transplantation in plastic pots filled with sterile soilrite where 85% plantlets grew well and all exhibited normal development. The present findings describe an efficient and rapid plant regeneration protocol that can further be used for genetic transformation studies.
Indian Academy of Sciences (India)
J Santhanalakshmi; G Shantha Lakshmi; V K Aswal; P S Goyal
2001-02-01
Small angle neutron scattering (SANS) measurements of D2O solutions (0 1 M) of sodium cholate (NaC) and sodium deoxycholate (NaDC) were carried out at = 298 K. Under compositions very much above the critical micelle concentration (CMC), the bile salt micelle size growths were monitored by adopting Hayter-Penfold type analysis of the scattering data. NaC and NaDC solutions show presence of correlation peaks at = 0 12 and 0 1 Å-1 respectively. Monodisperse ellipsoids of the micelles produce best fits. For NaC and NaDC systems, aggregation number (9 0, 16 0), fraction of the free counterions per micelle (0 79, 0 62), semi-minor (8 0 Å) and semi-major axes (18 4, 31 7 Å) values for the micelles were deduced. Extent of micellar growth was studied using ESR correlation time measurements on a suitable probe incorporating NaC and NaDC micelles. The growth parameter (axial ratio) values were found to be 2 3 and 4 0 for NaC and NaDC systems respectively. The values agree with those of SANS.
Multiple fixed drug eruption caused by iomeprol (Iomeron), a nonionic contrast medium.
Watanabe, H; Sueki, H; Nakada, T; Akiyama, M; Iijima, M
1999-01-01
Most cases of drug eruption caused by nonionic contrast media (NICM) reported to date have been of the erythema multiforme type. Herein we report the first case of multiple fixed drug eruption (FDE) caused by iomeprol (Iomeron(R)). A 67-year-old woman developed multiple pea-sized erythematous papules on the trunk and extremities 4 days after receiving 100 ml of iomeprol for a computed tomography examination. Some of the papules coalesced, forming 7 large plaques on the limbs. Six months later, the patient was mistakenly administered iomeprol again. On the following morning, erythematous plaques admixed with vesicles recurred at the same sites as during the previous episode. In both episodes, the lesions cleared leaving pigmentation that faded with 6 weeks. Both patch testing and an intradermal test with iomeprol on lesional pigmented skin were positive. The present case indicates that NICM may cause multiple FDE and that repeated administration of the causative agent may increase the severity of the eruption.
Ruiz-Lopez, M. F.; Loos, M.; Goulon, J.; Benfatto, M.; Natoli, C. R.
1988-04-01
This paper produces direct evidences that even non-collinear scattering paths can give rise to well-detectable and interpretable signatures in EXAFS spectra. Ferrocene or nickelocene are most favourable examples to study these rather small signals because the shortest intermolecular distances are too large to interfer with them and add no significant contribution to the EXAFS spectrum. For the first time, we have been able to resolve in the R-space individual contributions of specific double and triple scattering paths and also to reproduce their relative amplitudes and phases using full ab initio simulations carried out in the general regime of spherical wave propagation of the ejected/scattered photoelectron. Due to considerable rotational disorder of the cyclopentadienyl (C p) rings, especially at room temperature, all multiple scattering paths involving carbon atoms located on different rings were found to vanish. Full multiple scattering XANES calculations have also been performed on the same systems and were shown to be identical in the staggered (D 5d) or eclipsed (D 5h) conformations of the C p rings. The experimental XANES spectra exhibit a shoulder which is better resolved in the case of ferrocene: our simulations have established the origin of this shoulder and that its resolution was sensitive to small variations of the metal…C bond lengths. The weak pre-edge structure can be explained either by a quadrupolar allowed transition to an antibonding (3d-like) excited state of symmetry 5e 1g if the rings have D 5d group symmetry, or by a disorder-allowed dipolar transition to the corresponding state if the group symmetry is reduced to D 5. In the case of ferrocene, there is also an additional "bump" at ≈ 12 eV past the main absorption peak, which is not reproduced by our single-electron calculations: a possible interpretation which, however, is not yet firmly established, is to assign this feature to a multielectron shakeup satellite.
Energy Technology Data Exchange (ETDEWEB)
Colognesi, Daniele; Celli, Milva; Ulivi, Lorenzo, E-mail: lorenzo.ulivi@isc.cnr.it [Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); Powers, Anna; Xu, Minzhong [Department of Chemistry, New York University, New York, New York 10003 (United States); Bačić, Zlatko, E-mail: zlatko.bacic@nyu.edu [Department of Chemistry, New York University, New York, New York 10003 (United States); NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062 (China)
2014-10-07
We report inelastic neutron scattering (INS) measurements on molecular hydrogen deuteride (HD) trapped in binary cubic (sII) and hexagonal (sH) clathrate hydrates, performed at low temperature using two different neutron spectrometers in order to probe both energy and momentum transfer. The INS spectra of binary clathrate samples exhibit a rich structure containing sharp bands arising from both the rotational transitions and the rattling modes of the guest molecule. For the clathrates with sII structure, there is a very good agreement with the rigorous fully quantum simulations which account for the subtle effects of the anisotropy, angular and radial, of the host cage on the HD microscopic dynamics. The sH clathrate sample presents a much greater challenge, due to the uncertainties regarding the crystal structure, which is known only for similar crystals with different promoter, but nor for HD (or H{sub 2}) plus methyl tert-butyl ether (MTBE-d12)
Chen, Y.; García de Abajo, F. J.; Chassé, A.; Ynzunza, R. X.; Kaduwela, A. P.; van Hove, M. A.; Fadley, C. S.
1998-11-01
The Rehr-Albers (RA) separable Green's-function formalism, which is based on an expansion series, has been successful in speeding up multiple-scattering cluster calculations for photoelectron diffraction simulations, particularly in its second-order version. The performance of this formalism is explored here in terms of computational speed, convergence over orders of multiple scattering, over orders of approximation, and over cluster size, by comparison with exact cluster-based formalisms. It is found that the second-order RA approximation [characterized by (6×6) scattering matrices] is adequate for many situations, particularly if the initial state from which photoemission occurs is of s or p type. For the most general and quantitative applications, higher-order versions of RA may become necessary for d initial states [third-order, i.e., (10×10) matrices] and f initial states [fourth-order, i.e., (15×15) matrices]. However, the required RA order decreases as an electron wave proceeds along a multiple-scattering path, and this can be exploited, together with the selective and automated cutoff of weakly contributing matrix elements and paths, to yield computer time savings of at least an order of magnitude with no significant loss of accuracy. Cluster sizes of up to approximately 100 atoms should be sufficient for most problems that require about 5% accuracy in diffracted intensities. Excellent sensitivity to structure is seen in comparisons of second-order theory with variable geometry to exact theory as a fictitious ``experiment.'' Our implementation of the Rehr-Albers formalism thus represents a versatile, quantitative, and efficient method for the accurate simulation of photoelectron diffraction.
Multiple Absorption-Line Spectroscopy of the Intergalactic Medium. I. Model
Yao, Yangsen; Danforth, Charles W; Keeney, Brian A; Stocke, John T
2011-01-01
We present a physically-based absorption-line model for the spectroscopic study of the intergalactic medium (IGM). This model adopts results from Cloudy simulations and theoretical calculations by Gnat and Sternberg (2007) to examine the resulting observational signatures of the absorbing gas with the following ionization scenarios: collisional ionization equilibrium (CIE), photoionization equilibrium, hybrid (photo- plus collisional ionization), and non-equilibrium cooling. As a demonstration, we apply this model to new observations made with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope of the IGM absorbers at z~0.1877 along the 1ES 1553+113 sight line. We identify Ly alpha, C III, O VI, and N V absorption lines with two distinct velocity components (blue at z_b=0.18757; red at z_r=0.18772) separated by Delta(cz)/(1+z)~38 km/s. Joint analyses of these lines indicate that none of the examined ionization scenarios can be applied with confidence to the blue velocity component, although phot...
Hirst, Evan; Thompson, Oliver; Andrews, Mike
2013-02-01
The retina/choroid structure is an example of a complex biological target featuring highly perfused tissues and vessel flows both near the surface and at some depth. Laser speckle imaging can be used to image blood flows but static scattering paths present a problem for extracting quantifiable data. The speckle contrast is artificially increased by any residual specular reflection and light paths where no moving scatterers are encountered. Here we present results from phantom experiments demonstrating that the static and dynamic contributions to laser speckle contrast can be separated when camera exposures of varying duration are used. The stationary contrast parameter follows the thickness and strength of the overlying scatterer while the dynamic proportion of the scatter resulting from vessel flows and Brownian motion is unchanged. The importance of separating the two scatter components is illustrated by in vivo measurements from a scarred human retina, where the effect of the un-perfused scar tissue can be decoupled from the dynamic speckle from the intact tissue beneath it.
Institute of Scientific and Technical Information of China (English)
杜建科; 沈亚鹏; 高波
2004-01-01
A theoretical treatment of the scattering of anti-plane shear (SH) waves is provided by a single crack in an unbounded transversely isotropic electro-magneto-elastic medium. Based on the differential equations of equilibrium, electric displacement and magnetic induction intensity differential equations, the governing equations for SH waves were obtained. By means of a linear transform, the governing equations were reduced to one Helmholtz and two Laplace equations. The Cauchy singular integral equations were gained by making use of Fourier transform and adopting electro-magneto impermeable boundary conditions. The closed form expression for the resulting stress intensity factor at the crack was achieved by solving the appropriate singular integral equations using Chebyshev polynomial. Typical examples are provided to show the loading frequency upon the local stress fields around the crack tips. The study reveals the importance of the electromagneto-mechanical coupling terms upon the resulting dynamic stress intensity factor.
Rizzuti, G.; Gisolf, A.
2017-03-01
We study a reconstruction algorithm for the general inverse scattering problem based on the estimate of not only medium properties, as in more conventional approaches, but also wavefields propagating inside the computational domain. This extended set of unknowns is justified as a way to prevent local minimum stagnation, which is a common issue for standard methods. At each iteration of the algorithm, (i) the model parameters are obtained by solution of a convex problem, formulated from a special bilinear relationship of the data with respect to properties and wavefields (where the wavefield is kept fixed), and (ii) a better estimate of the wavefield is calculated, based on the previously reconstructed properties. The resulting scheme is computationally convenient since step (i) can greatly benefit from parallelization and the wavefield update (ii) requires modeling only in the known background model, which can be sped up considerably by factorization-based direct methods. The inversion method is successfully tested on synthetic elastic datasets.
Tabrizi, Mehdi
2016-10-01
The multiple scattering effect on the linewidth of backward Parametric X-ray Radiation (PXR) produced in the extremely Bragg geometry by low energy relativistic electrons traversing a single crystal is discussed. It is shown that there are conditions when the influence of photoabsorption on the linewidth can be neglected, and only the multiple scattering process of relativistic electrons in crystals leads to the PXR lines broadening. Based on obtained theoretical and numerical results for the linewidth broadening caused by multiple scattering of 30 and 50 MeV relativistic electrons in a Si crystal of various thicknesses, an experiment could be performed to help in revealing the scattering effect on the PXR lines in the absence of photoabsorption. This leads to more accurate understanding of the influence of scattering process on the linewidth of backward PXR and helps to better construct a table-top narrow bandwidth X-ray source for both scientific and industrial applications.
Impact of the in-medium conservation of energy on the π-/π+ multiplicity ratio
Cozma, M. D.
2016-05-01
An upgraded version of the isospin dependent T¨ubingen QMD transport model, which allows the conservation of the total energy, is presented. This is achieved by including in the energy-balance equations of the density, isospin asymmetry and momentum dependent inmedium baryon potential energies. It leads to an effective modification of particle production thresholds with respect to the vacuum ones. Compatible constraints for the symmetry energy stiffness from π-/π+ multiplicity ratio and elliptic flow experimental data of Au+Au collisions at 400 MeV/nucleon can be extracted in this case. However, an important dependence of the π-/π+ observable on the strength of the isovector part of the Δ(1232) isobar potential is also demonstrated. The present lack of information on this quantity prevents a precise extraction of the value for the symmetry energy stiffness employing the mentioned observable alone.
A new method for calculating the Glauber multiple scattering amplitude of composite particles
Zhang, Yu-Shun; Hu, Su-Fen; Yang, Chao-Yun; Liu, Ji-Feng
1997-11-01
The method for calculating the scattering of composite particles with several kinds of constituent is studied. The formulae are derived and the method for sorting all Glauber expansion terms into several classes is given. The method of the integration is different from that of Lin and co-workers (Lin Z J et al 1991 J. Phys. G: Nucl. Part. Phys. 17 1159) and its analytical expressions are introduced. We calculate the D - D, P - P, P - 0954-3899/23/11/005/img7 and 0954-3899/23/11/005/img8 - P elastic scatterings. These results are compared with the data.
Elhanaoui, Abdelkader; Aassif, Elhoucein; Maze, Gérard; Décultot, Dominique
2016-02-01
The present paper studies the acoustic signal backscattered by an air-filled copper–solid polymer two-layer cylindrical tube immersed in water. The work is done from the calculation of the backscattered pressure, an inverse Fourier Transform, which allows us to obtain an impulse signal. Smoothed pseudo Wigner–Ville and Concentrated spectrogram representations have been chosen to analyze the scattering phenomenon. For reduced frequencies ranging from 0.1 to 200, the resonance trajectories and time–frequency images have shown the presence of the guided waves. The bifurcation of the A0 wave into the A0(-) and the A0(+) waves has also been observed. The authors provide the phase and the group velocities of guided waves and investigate the differences between curves. The findings are then compared with those obtained for the copper and the solid polymer one-layer cylindrical tubes. Group velocity values have also been extracted from smoothed pseudo Wigner–Ville and Concentrated spectrogram time–frequency images. A good agreement with the theory has, therefore, been observed. The study of acoustic backscattering by a copper–solid polymer two-layer tube has revealed the interaction and the coupling of guided waves, specially the presence of a pseudo A1 wave; which is a very interesting, remarkable phenomenon.
Energy Technology Data Exchange (ETDEWEB)
Airapetian, A. [Giessen Univ. (Germany). Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Lab. of Physics; Akopov, N. [Yerevan Physics Institute (Armenia); Akopov, Z. [DESY Hamburg (Germany)] [and others; Collaboration: HERMES Collaboration
2012-12-15
Multiplicities in semi-inclusive deep-inelastic scattering are presented for each charge state of {pi}{sup {+-}} and K{sup {+-}} mesons. The data were collected by the HERMES experiment at the HERA storage ring using 27.6 GeV electron and positron beams incident on a hydrogen or deuterium gas target. The results are presented as a function of the kinematic quantities x{sub B}, Q{sup 2}, z, and P{sub h} {sub perpendicular} {sub to}. They represent a unique data set for identified hadrons that will significantly enhance our understanding of the fragmentation of quarks into final-state hadrons in deep-inelastic scattering.
Institute of Scientific and Technical Information of China (English)
Wang Hai-Hua; Sun Xian-Ming
2012-01-01
The mixture of water cloud droplets with black carbon impurities is modeled by external and internal mixing models.The internal mixing model is modeled with a two-layered sphere(water cloud droplets containing black carbon(BC)inclusions),and tihe single scattering and absorption characteristics are calculated at the visible wavelength of 0.55 μm by using the Lorenz Mie theory.The external mixing model is developed assuming that the same amount of BC particles are mixed with the water droplets externally.The multiple scattering characteristics we computed by using the Monte Carlo method.The results show that when the size of the BC aerosol is small,the reflection intensity of the internal mixing model is bigger than that of the external mixing model.However,if the size of the BC aerosol is big,the absorption of the internal mixing model will be larger than that of the external mixing model.
Institute of Scientific and Technical Information of China (English)
李凤明; 胡超; 徐敏强; 黄文虎
2003-01-01
Based on the theory of elastic dynamics, multiple scattering of elastic waves anddynamic stress concentrations in fiber-reinforced composite are studied. The analytical expressions ofelastic waves in different regions are presented. The mode coefficients of elastic waves are determinedin accordance with the continuous conditions of displacement and stress on the boundary of the multi-interfaces. By using the addition theorem of Hankel functions, the formula of scattered wave fields indifferent local coordinates are transformed into those in one local coordinate to determine the unknowncoefficients and dynamic stress concentration factors (DSCFs). The influences of the distance betweentwo inclusions, material properties and structural size on the DSCFs near the interfaces are analyzed.As examples, the numerical results of DSCFs near the interfaces for two kinds of fiber-reinforcedcomposites are presented and discussed.
Institute of Scientific and Technical Information of China (English)
李凤明; 胡超; 徐敏强; 黄文虎
2003-01-01
Based on the theory of elastic dynamics,multiple scattering of elastic waves and dynamic stress concentrations in fiber-reinforced composite are studied.The analytical expressions of elastic waves in different regions are presented.The mode coefficients of elastic waves are determined in accordance with the continuous conditions of displacement and stress on the boundary of the multiinterfaces.By using the addition theorem of Hankel functions,the formula of scattered wave fields in different local coordinates are transformed into those in one local coordinate to determine the unknown coefficients and dynamic stress concentration factors (DSCFs).The influences of the distance between two inclusions,material properties and structural size on the DSCFs near the interfaces are analyzed.As examples,the numerical results of DSCFs near the interfaces for two kinds of fiber-reinforced composites are presented and discussed.
The significance of multiple scattering in bubble measurements near the sea surface
DEFF Research Database (Denmark)
Jensen, Leif Bjørnø; Bjørnø, Irina K.
1996-01-01
The acoustic interactions between gas bubbles in bubble plumes formed near the sea surface may significantly change the propagation and attenuation conditions for acoustical signals in the sea. The scattering properties of the bubble plumes have been studied extensively since Foldy's formulation...
Energy Technology Data Exchange (ETDEWEB)
Resel, Roland, E-mail: roland.resel@tugraz.at; Bainschab, Markus; Pichler, Alexander [Graz University of Technology, Graz (Austria); Dingemans, Theo [Delft University of Technology, Delft (Netherlands); Simbrunner, Clemens [Johannes Kepler University, Linz (Austria); University of Bremen, Bremen (Germany); Stangl, Julian [Johannes Kepler University, Linz (Austria); Salzmann, Ingo [Humboldt University, Berlin (Germany)
2016-04-20
The use of grazing-incidence X-ray diffraction to determine the crystal structure from thin films requires accurate positions of Bragg peaks. Refraction effects and multiple scattering events have to be corrected or minimized. Dynamical scattering effects are observed in grazing-incidence X-ray diffraction experiments using an organic thin film of 2,2′:6′,2′′-ternaphthalene grown on oxidized silicon as substrate. Here, a splitting of all Bragg peaks in the out-of-plane direction (z-direction) has been observed, the magnitude of which depends both on the incidence angle of the primary beam and the out-of-plane angle of the scattered beam. The incident angle was varied between 0.09° and 0.25° for synchrotron radiation of 10.5 keV. This study reveals comparable intensities of the split peaks with a maximum for incidence angles close to the critical angle of total external reflection of the substrate. This observation is rationalized by two different scattering pathways resulting in diffraction peaks at different positions at the detector. In order to minimize the splitting, the data suggest either using incident angles well below the critical angle of total reflection or angles well above, which sufficiently attenuates the contributions from the second scattering path. This study highlights that the refraction of X-rays in (organic) thin films has to be corrected accordingly to allow for the determination of peak positions with sufficient accuracy. Based thereon, a reliable determination of the lattice constants becomes feasible, which is required for crystallographic structure solutions from thin films.
Wang, Kezhi
2014-09-01
The sum of ratios of products of independent 2642 2642α-μ random variables (RVs) is approximated by using the Generalized Gamma ratio approximation (GGRA) with Gamma ratio approximation (GRA) as a special case. The proposed approximation is used to calculate the outage probability of the equal gain combining (EGC) or maximum ratio combining (MRC) receivers for wireless multihop relaying or multiple scattering systems considering interferences. Numerical results show that the newly derived approximation works very well verified by the simulation, while GRA has a slightly worse performance than GGRA when outage probability is below 0.1 but with a more simplified form.
Multiple scattering of polarized light in turbid infinite planes: Monte Carlo simulations.
Otsuki, Soichi
2016-05-01
Monte Carlo simulations were performed for infinite plane media containing spherical particles of different sizes. Most of the features of the surface plots for the elements of the effective scattering Mueller matrices are explained by the azimuthal dependence of the matrix predicted according to the theory of Raković et al. [Appl. Opt.38, 3399 (1999)10.1364/AO.38.003399APOPAI1559-128X]. The reduced effective scattering Mueller matrices calculated according to the theory have eight nonzero elements, which are only dependent on the distance from the illumination point. The reduced matrices are factorized approximately into products of a depolarizer and retarding diattenuators. The turbid infinite plane media nearly behave as a pure depolarizer at long distances and become more diattenuating and birefringent with decreasing distance.
Multiple-Scattering Approach to the Formation of the Impurity Band in Semiconductors
Ghazali, A.; Serre, J.
1982-03-01
The electronic structure of doped semiconductors is studied by using the best approximation of Klauder's impurity-scattering theory which yields a wave-vector- and energy-dependent self-energy Σ(k-->,E). An approximation is used for electron correlation effects. It is shown that as the impurity concentration is decreased, the conduction-band tail progressively splits off, giving an impurity band. The link between the formation of the latter and the general theory of bifurcation is outlined.
Mete, Oznur; Xia, Guoxing; Labiche, Marc; Karamyshev, Oleg; Wei, Yelong; Welsch, Carsten; Wing, Matthew
2014-01-01
Alternative acceleration technologies are currently under development for cost-effective, robust, compact and efficient solutions. One such technology is plasma wakefield acceleration, driven by either a charged particle or laser beam. However, the potential issues must be studied in detail. In this paper, the emittance growth of the witness beam through elastic scattering from gaseous media is derived. The model is compared with the numerical studies.
Indian Academy of Sciences (India)
Bharat Chandra Routara; Saumya Darsan Mohanty; Saurav Datta; Asish Bandyopadhyay; Siba Sankar Mahapatra
2010-10-01
The present study highlights a multi-objective optimization problem by applying utility concept coupled with Taguchi method through a case study in CNC end milling of UNS C34000 medium leaded brass. The study aimed at evaluating the best process environment which could simultaneously satisfy multiple requirements of surface quality. In view of the fact, the traditional Taguchi method cannot solve a multi-objective optimization problem; to overcome this limitation, utility theory has been coupled with Taguchi method. Depending on Taguchi’s Lower-the-Better (LB) response criteria; individual surface quality characteristics has been transformed into corresponding utility values. Individual utility values have been aggregated ﬁnally to compute overall utility degree which serves as representative objective function for optimizing using Taguchi method. Utility theory has been adopted to convert a multi-response optimization problem into a single response optimization problem; in which overall utility degree serves as the representative single objective function for optimization. The study of combined utility theory and Taguchi method for predicting optimal setting. Based on Taguchi’s Signal-to-Noise ratio (S/N), analysis has been made on the overall utility degree and optimal process environment has been selected ﬁnally which corresponds to highest S/N Ratio. Optimal result has been veriﬁed through conﬁrmatory test. The case study indicates application feasibility of the aforesaid methodology proposed for multiresponse optimization and off-line control of multiple surface quality characteristics in CNC end milling.
Directory of Open Access Journals (Sweden)
Sokolov Rosen S.
2015-12-01
Full Text Available In this study, the effects of compounds providing Fe in chelated (NaFeEDTA and Fe(IIIAC and non-chelated (FeSO4·7H2O forms as components of culture media, on in vitro shoot multiplication and rooting of Magnolia soulangeana ‘Alexandrina’, Magnolia grandiflora and Prunus cerasifera ‘Nigra’ were comparatively evaluated. Each of the tested chemicals was used as a single Fe source in the basal salt medium. In the stages of shoot multiplication and rooting plant response was scored by biometrical indices (number of shoots, leaves and roots, shoot and root length, percent of rooted plants and root hairs. The occurrence of physiological disorders was estimated by visual observations. In presence of FeSO4, symptoms of chlorosis, hyperhy-dricity, early senescence and specific morphology of roots, suggesting Fe deficiency, were observed. These deteriorations were entirely prevented at the application of Fe chelates of which, in this experimental systems, Fe(IIIAC was tested for the first time. The addition of Fe(IIIAC positively affected the plant quality to extent comparable to that of NaFeEDTA. The obtained data suggest that both applied Fe chelates are more appropriate than non-chelated Fe form and can be alternatively used in the optimization of nutrient media for micropropagation of Magnolia and Prunus cerasifera genotypes.
Energy Technology Data Exchange (ETDEWEB)
Nakatsuka, Takao [Okayama Shoka University, Laboratory of Information Science, Okayama (Japan); Okei, Kazuhide [Kawasaki Medical School, Dept. of Information Sciences, Kurashiki (Japan); Iyono, Atsushi [Okayama university of Science, Dept. of Fundamental Science, Faculty of Science, Okayama (Japan); Bielajew, Alex F. [Univ. of Michigan, Dept. Nuclear Engineering and Radiological Sciences, Ann Arbor, MI (United States)
2015-12-15
Simultaneous distribution between the deflection angle and the lateral displacement of fast charged particles traversing through matter is derived by applying numerical inverse Fourier transforms on the Fourier spectral density solved analytically under the Moliere theory of multiple scattering, taking account of ionization loss. Our results show the simultaneous Gaussian distribution at the region of both small deflection angle and lateral displacement, though they show the characteristic contour patterns of probability density specific to the single and the double scatterings at the regions of large deflection angle and/or lateral displacement. The influences of ionization loss on the distribution are also investigated. An exact simultaneous distribution is derived under the fixed energy condition based on a well-known model of screened single scattering, which indicates the limit of validity of the Moliere theory applied to the simultaneous distribution. The simultaneous distribution will be valuable for improving the accuracy and the efficiency of experimental analyses and simulation studies relating to charged particle transports. (orig.)
Directory of Open Access Journals (Sweden)
C. Adolph
2017-01-01
Full Text Available Multiplicities of charged pions and charged hadrons produced in deep-inelastic scattering were measured in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y and the relative hadron energy z. Data were obtained by the COMPASS Collaboration using a 160GeV muon beam and an isoscalar target (6LiD. They cover the kinematic domain in the photon virtuality Q2>1(GeV/c2, 0.004
Adolph, C.; Aghasyan, M.; Akhunzyanov, R.; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anfimov, N.V.; Anosov, V.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badelek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Buechele, M.; Capozza, L.; Chang, W. -C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S. -U.; Cicuttin, A.; Crespo, M.L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O. Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Duic, V.; Duennweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmueller, S.; Grasso, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; von Harrach, D.; Hashimoto, R.; Heinsius, F.H.; Heitz, R.; Herrmann, F.; Hinterberger, F.; Horikawa, N.; dHose, N.; Hsieh, C. -Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Joosten, R.; Joerg, P.; Kabuss, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Koenigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.M.; Kuhn, R.; Kraemer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Marchand, C.; Marianski, B.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.V.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Montuenga, P.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nikolaenko, V.I.; Novy, J.; Nowak, W. -D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J. -C.; Pereira, F.; Pesek, M.; Peshekhonov, D.V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Roskot, M.; Ryabchikov, D.I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schoenning, K.; Schopferer, S.; Seder, E.; Selyunin, A.; Shevchenko, O. Yu.; Steffen, D.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Sozzi, F.; Srnka, A.; Stolarski, M.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tosello, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Vondra, J.; Weisrock, T.; Wilfert, M.; Windmolders, R.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.
2017-01-01
Multiplicities of charged pions and unidentified hadrons produced in deep-inelastic scattering were measured in bins of the Bjorken scaling variable $x$, the relative virtual-photon energy $y$ and the relative hadron energy $z$. Data were obtained by the COMPASS Collaboration using a 160 GeV muon beam and an isoscalar target ($^6$LiD). They cover the kinematic domain in the photon virtuality $Q^2$ > 1(GeV/c$)^2$, $0.004 < x < 0.4$, $0.2 < z < 0.85$ and $0.1 < y < 0.7$. In addition, a leading-order pQCD analysis was performed using the pion multiplicity results to extract quark fragmentation functions.
Adolph, C.; Aghasyan, M.; Akhunzyanov, R.; Alexeev, G. D.; Alexeev, M. G.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C. D. R.; Badełek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Capozza, L.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S.-U.; Cicuttin, A.; Crespo, M. L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Dhara, L.; Donskov, S. V.; Doshita, N.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P. D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; von Harrach, D.; Hashimoto, R.; Heinsius, F. H.; Heitz, R.; Herrmann, F.; Hinterberger, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O. M.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kuhn, R.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G. K.; Marchand, C.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G. V.; Meyer, M.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Montuenga, P.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nikolaenko, V. I.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A. S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Roskot, M.; Rossiyskaya, N. S.; Ryabchikov, D. I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Schopferer, S.; Seder, E.; Selyunin, A.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Sozzi, F.; Srnka, A.; Steffen, D.; Stolarski, M.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tosello, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Vondra, J.; Weisrock, T.; Wilfert, M.; Windmolders, R.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Zink, A.
2017-01-01
Multiplicities of charged pions and charged hadrons produced in deep-inelastic scattering were measured in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y and the relative hadron energy z. Data were obtained by the COMPASS Collaboration using a 160GeV muon beam and an isoscalar target (6LiD). They cover the kinematic domain in the photon virtuality Q2 > 1(GeV / c) 2, 0.004 < x < 0.4, 0.2 < z < 0.85 and 0.1 < y < 0.7. In addition, a leading-order pQCD analysis was performed using the pion multiplicity results to extract quark fragmentation functions.
Lund, E; Hughes, E W; Lopez Mateos, D; Salzburger, A; Strandlie, A
2008-01-01
In this paper we study the energy loss, its fluctuations, and the multiple scattering of particles passing through matter, with an emphasis on muons. In addition to the well-known Bethe-Bloch and Bethe-Heitler equations describing the mean energy loss from ionization and bremsstrahlung respectively, new parameterizations of the mean energy loss of muons from the direct e+e- pair production and photonuclear interactions are presented along with new estimates of the most probable energy loss and its fluctuations in the ATLAS calorimeters. Moreover, a new adaptive Highland/Moliere approach to finding the multiple scattering angle is taken to accomodate a wide range of scatterer thicknesses. Furthermore, tests of the muon energy loss, its fluctuations, and multiple scattering are done in the ATLAS calorimeters. The material effects described in this paper are all part of the simultaneous track and error propagation (STEP) algorithm of the common ATLAS tracking software.
Yang, Shin Nan
2014-01-01
A simple heuristic argument to understand the existence of complex branch points in the $\\pi N$ scattering amplitude is presented. It is based on a hypothesis that the singularity structure of the $\\pi N$ scattering amplitude is a smooth varying function of the pion mass. We then show that the two-pole structure found to correspond to the Roper resonance could just a simple direct mathematical consequence of including additional Riemann surface in the analysis. Our study indicates that it is always possible to have multiple poles, either two or four etc., in different Riemann sheet, to be associated with a resonance. The poles in all Riemann sheets should be looked for to determine whether the two-pole feature of the Roper resonance $N^*(1440)$ is a manifestation of the "exact degeneracy" discussed here but masked by numerical indeterminacy, or an "accidental" one. The determination of the multiplicity of a pole could provide some information of the analytical structure of the numerator of the pole term, as t...
Wang, Kezhi
2015-06-01
Exact results for the probability density function (PDF) and cumulative distribution function (CDF) of the sum of ratios of products (SRP) and the sum of products (SP) of independent α-μ random variables (RVs) are derived. They are in the form of 1-D integral based on the existing works on the products and ratios of α-μ RVs. In the derivation, generalized Gamma (GG) ratio approximation (GGRA) is proposed to approximate SRP. Gamma ratio approximation (GRA) is proposed to approximate SRP and the ratio of sums of products (RSP). GG approximation (GGA) and Gamma approximation (GA) are used to approximate SP. The proposed results of the SRP can be used to calculate the outage probability (OP) for wireless multihop relaying systems or multiple scattering channels with interference. The proposed results of the SP can be used to calculate the OP for these systems without interference. In addition, the proposed approximate result of the RSP can be used to calculate the OP of the signal-To-interference ratio (SIR) in a multiple scattering system with interference. © 1967-2012 IEEE.
A Two-Dimensional Helmholtz Equation Solution for the Multiple Cavity Scattering Problem
2013-02-01
present an efficient block Gauss– Seidel method , which may be written as follows: given ðuð0Þ1 ; ;u ð0Þ n Þ>, define ðuðkÞ1 ; . . . ;u ðkÞ n Þ>; k P...well-posed single cavity scattering problems (5.5)–(5.7) for the block Gauss– Seidel method at each iteration. 5.2. Transparent boundary condition... Seidel method for two consecutive approx- imations again the number of iterations for all three types of cavities. It can be seen from Fig. 10 that
Polarization control of multiply-scattered light through random media by wavefront shaping
Guan, Yefeng; Small, Eran; Zhou, Jianying; Silberberg, Yaron
2015-01-01
We show that the polarization state of coherent light propagating through an optically thick multiple-scattering medium, can be controlled by wavefront shaping, i.e. by controlling only the spatial phase of the incoming field with a spatial light modulator. Any polarization state of light at any spatial position behind the scattering medium can be attained with this technique. Thus, transforming the random medium to an arbitrary optical polarization component becomes possible.
Scatter Characterization and Correction for Simultaneous Multiple Small-Animal PET Imaging
Prasad, Rameshwar; Zaidi, Habib
2014-01-01
The rapid growth and usage of small-animal positron emission tomography (PET) in molecular imaging research has led to increased demand on PET scanner's time. One potential solution to increase throughput is to scan multiple rodents simultaneously. However, this is achieved at the expense of deterio
Li, Xiang-Guo; Zhang, X -G; Cheng, Hai-Ping
2015-01-01
Electron transport in graphene is along the sheet but junction devices are often made by stacking different sheets together in a "side-contact" geometry which causes the current to flow perpendicular to the sheets within the device. Such geometry presents a challenge to first-principles transport methods. We solve this problem by implementing a plane-wave based multiple scattering theory for electron transport. This implementation improves the computational efficiency over the existing plane-wave transport code, scales better for parallelization over large number of nodes, and does not require the current direction to be along a lattice axis. As a first application, we calculate the tunneling current through a side-contact graphene junction formed by two separate graphene sheets with the edges overlapping each other. We find that transport properties of this junction depend strongly on the AA or AB stacking within the overlapping region as well as the vacuum gap between two graphene sheets. Such transport beh...
Serre, J.; Ghazali, A.
1983-10-01
Klauder's best multiple-scattering approximation which allows the use of a realistic interaction potential and in which electron-electron interactions may be incorporated is shown to constitute a sound basis for the study of the electronic structure of doped semiconductors. The implementation of this formalism requires the solution of a self-consistent set of nonlinear integral equations. This has been done numerically over a large impurity-concentration range. We have thus shown that as the concentration decreases, the band tail gradually splits off from the main band, giving an impurity band. Spectral-density analysis allows one to distinguish between localized and extended states. Compensation effects have also been analyzed. Finally, our results are discussed and compared with various experiments.
Ahn, Jae-Hyun; Park, Young-Je; Kim, Wonkook; Lee, Boram
2016-12-26
An estimation of the aerosol multiple-scattering reflectance is an important part of the atmospheric correction procedure in satellite ocean color data processing. Most commonly, the utilization of two near-infrared (NIR) bands to estimate the aerosol optical properties has been adopted for the estimation of the effects of aerosols. Previously, the operational Geostationary Color Ocean Imager (GOCI) atmospheric correction scheme relies on a single-scattering reflectance ratio (SSE), which was developed for the processing of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data to determine the appropriate aerosol models and their aerosol optical thicknesses. The scheme computes reflectance contributions (weighting factor) of candidate aerosol models in a single scattering domain then spectrally extrapolates the single-scattering aerosol reflectance from NIR to visible (VIS) bands using the SSE. However, it directly applies the weight value to all wavelengths in a multiple-scattering domain although the multiple-scattering aerosol reflectance has a non-linear relationship with the single-scattering reflectance and inter-band relationship of multiple scattering aerosol reflectances is non-linear. To avoid these issues, we propose an alternative scheme for estimating the aerosol reflectance that uses the spectral relationships in the aerosol multiple-scattering reflectance between different wavelengths (called SRAMS). The process directly calculates the multiple-scattering reflectance contributions in NIR with no residual errors for selected aerosol models. Then it spectrally extrapolates the reflectance contribution from NIR to visible bands for each selected model using the SRAMS. To assess the performance of the algorithm regarding the errors in the water reflectance at the surface or remote-sensing reflectance retrieval, we compared the SRAMS atmospheric correction results with the SSE atmospheric correction using both simulations and in situ match-ups with the
Lee, Taewoong; Yoon, Changyeon; Lee, Wonho
2014-06-01
During radiation therapy, the irradiated position and the energy deposited in a patient must be monitored. In general, calculations before photon exposure or 2D measurements of the transmitted photons have been widely used for making dose estimates. In this paper, we propose a real-time 3D dose measurement using Compton imaging technology. On the basis of the Monte-Carlo method, we designed a multiple-scattering Compton camera system (MSCC) with semiconductor and scintillation detectors. The MSCC was constructed with two semiconductor detectors as scattering detectors and a cadmium-tungstate (CWO) scintillator detector as an absorber detector. The two planar semiconductor arrays, and the CWO array consisted of 40 × 40 pixels, each with a size of 1 × 1 × ɛ mm3, where ɛ is the variable thickness of the detectors. The design parameters, such as the types of semiconductors, detector thicknesses and distances between detectors, were optimized on the basis of the detection efficiency and angular resolution of reconstructed images for a point source. Under the optimized conditions, uncertainty factors in geometry and energy were estimated for various inter-detector distances. We used a source corresponding to photons scattered from a water phantom exposed to 6-MeV peak X-rays. According to our simulation results, the figure of merit, reached its maximum value when the inter-detector distance was 3 cm. In order to achieve a high FOM, we chose 1 cm as the optimum thickness for the scattering and absorbed detectors. A cadmium-zinc-telluride (CZT) detector showed the best performance among the simulated semiconductors. The position uncertainty caused by the pixelization effect was the major factor in degrading the angular resolution of the reconstructed images, and the degradation caused by energy broadening was less than expected. The angular uncertainties caused by Doppler broadening and incorrect sequencing were minimal compared with that of pixelization. Our
Broggini, F.; Snieder, R.; Wapenaar, C.P.A.; Thorbecke, J.W.
2013-01-01
Seismic interferometry is a technique that allows one to reconstruct the full wavefield originating from a virtual source inside a medium, assuming a receiver is present at the virtual source location. We discuss a method that creates a virtual source inside a medium from reflection data measured at
Aghasyan, M.; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anfimov, N.V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badelek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Buechele, M.; Burtsev, V.E.; Capozza, L.; Chang, W. -C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chumakov, A.G.; Chung, S. -U.; Cicuttin, A.; Crespo, M.L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O. Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Dreisbach, Ch.; Duennweber, W.; Dusaev, R.R.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Faessler, M.; Ferrero, A.; Finger, M.; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giarra, J.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Gridin, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F.H.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C. -Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jary, V.; Joosten, R.; Joerg, P.; Kabuss, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Koenigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.M.; Kral, Z.; Kraemer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Kuznetsov, I.I.; Kveton, A.; Lednev, A.A.; Levchenko, E.A.; Levillain, M.; Levorato, S.; Lian, Y. -S.; Lichtenstadt, J.; Longo, R.; Lyubovitskij, V.E.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Mamon, S.A.; Marianski, B.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.V.; Meyer, M.; Meyer, W.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Moretti, A.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Novy, J.; Nowak, W. -D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J. -C.; Pereira, F.; Pesek, M.; Peskova, M.; Peshekhonov, D.V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rogacheva, N.S.; Ryabchikov, D.I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schoenning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vasilishin, B.I.; Vauth, A.; Veloso, J.; Vidon, A.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.
A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality $Q^{2}>1$ (GeV/$c$)$^2$, invariant mass of the hadronic system $W > 5$ GeV/$c^2$, Bjorken scaling variable in the range $0.003 < x < 0.4$, fraction of the virtual photon energy carried by the hadron in the range $0.2 < z < 0.8$, square of the hadron transverse momentum with respect to the virtual photon direction in the range 0.02 (GeV/$c)^2 < P_{\\rm{hT}}^{2} < 3$ (GeV/$c$)$^2$. The multiplicities are presented as a function of $P_{\\rm{hT}}^{2}$ in three-dimensional bins of $x$, $Q^2$, $z$ and compared to previous semi-inclusive measurements. We explore the small-$P_{\\rm{hT}}^{2}$ region, i.e. $P_{\\rm{hT}}^{2} < 1$ (GeV/$c$)$^2$, where hadron transverse momenta are expected to arise from non-perturbative effects, and also the d...
Directory of Open Access Journals (Sweden)
Mario Rodríguez Beraud
2015-03-01
Full Text Available The objective of the investigation was to evaluate the in-vitro multiplication of two varieties of blueberry (Vaccinium corymbosum L., “Brigitta” and “Legacy” in response to five explants densities (5, 10, 15, 20 and 25 and four flask volumes (10, 20, 30 and 40 mL for cultivation. For both varieties the cultivation medium WPM (Woody Plant Medium was used. The experiment was completely randomized with 20 treatments and 12 repetitions per treatment. After 45 days of cultivation we evaluated the height of shoots, number of shoots/explant, number of nodes/shoot and number of shoots/flask. Variety “Brigitta” had highest shoots at higher densities and flask volumes, while variety “Legacy” had the highest average shoot height with intermediate densities and high volumes. Regarding the number of shoots/explant, the volume of the medium had no influence on “Brigitta”, however, higher plant densities affected this parameter. With variety “Legacy” the maximum number of shoots was achieved with lower plant densities and intermediate culture volumes per flask. In relation to the number of nodes per explant "Brigitta had lower numbers as compared to “Legacy”, but with both varieties the number of nodes decresed with smaller volumes of medium in the flasks. For the number of shoots per flask, “Brigitta” responsed best at higher densities exceeding 40 shoots per flask. In contrast, “Legacy” produced maximum results at density of 25 explants in 30 mL of medium. It is concluded that for the optimum multiplication of both varieties the correct selection of both, the planting density and the volume of multiplication medium are important.
Impact of multiple frequency scattering on GNSS performance under adverse ionospheric conditions
Das, Aditi; Paul, Ashik
and L5 frequencies are closely spaced, their correlation coeffcients show good correspondence. It was observed that the response of L2 and L5 are nearly correlated. But correlation coefficients of L1:L5 and L1:L2 are low during scintillations and shows good correspondence with CNO fades. Similar effects were observed on the SV24 link on April 13, 2013 and on SV1 link on April 16, 2013. During October 2013, scintillations were observed at L1, L2 and L5 on the SV25 and 27 links on October 13, 2013, on the SV25 link on October 18, 2013, SV27 link on October 19, 2013 and SV1 and 27 links on October 21, 2013 respectively. Uncorrelated values of S4 and CNO fluctuations at L1:L2 and L1:L5 indicate different scattering mechanisms even within the same L-band possibly due to dynamic evolving nature of equatorial ionospheric irregularities. This issue is of serious concern in view of application of frequency diversity techniques for scintillation mitigation.
Experimental study of single-particle inclusive hadron scattering and associated multiplicities
Energy Technology Data Exchange (ETDEWEB)
Brenner, A.E.; Carey, D.C.; Elias, J.E.; Garbincius, P.H.; Mikenberg, G.; Polychronakos, V.A.; Aitkenhead, W.; Barton, D.S.; Brandenburg, G.W.; Busza, W.; Dobrowolski, T.; Friedman, J.I.; Kendall, H.W.; Lyons, T.; Nelson, B.; Rosenson, L.; Toy, W.; Verdier, R.; Votta, L.; Chiaradia, M.T.; DeMarzo, C.; Favuzzi, C.; Germinario, G.; Guerriero, L.; LaVopa, P.; Maggi, G.; Posa, F.; Selvaggi, G.; Spinelli, P.; Waldner, F.; Meunier, R.; Cutts, D.; Dulude, R.S.; Lanou, R.E. Jr.; Massimo, J.T.
1982-10-01
An experiment using the Fermilab single arm spectrometer (SAS) facility and an associated nonmagnetic vertex detector studied the reactions a+p..-->..c+X where a and c were ..pi../sup + -/, K/sup + -/, p, or p-bar. Extensive measurements were made at 100 and 175 GeV/c beam momenta with the outgoing hadrons detected in the SAS covering a kinematic range 0.12
Kawabata, Kiyoshi
2016-01-01
An efficient hybrid numerical method for multiple scattering calculations is proposed. We use the well established doubling--adding method to find the reflection function of the lowermost homogeneous slab comprising the atmosphere of our interest. This reflection function provides the initial value for the fast invariant imbedding method of Sato et al., (1977), with which layers are added until the final reflection function of the entire atmosphere is obtained. The execution speed of this hybrid method is no slower than one half of that of the doubling-adding method, probably the fastest algorithm available, even in the most unsuitable cases for the fast invariant imbedding method. The efficiency of the proposed method increases rapidly with the number of atmospheric slabs and the optical thickness of each slab. For some cases, its execution speed is approximately four times faster than the doubling--adding method. This work has been published in NAIS Journal (ISSN 1882-9392) Vol. 7, 5-16 (2012).
2014-07-01
In this paper we analyze the impact of the spontaneous Raman scattered noise generated from multiple optical classical channels on a single quantum key distribution channel, all within the telecom C-band. We experimentally measure the noise generated from up to 14 continuous lasers with different wavelengths using the dense wavelength division multiplexing (DWDM) standard, in both propagation directions in respect to the QKD channel, over different standard SMF-28 fiber lengths. We then simulate the expected secure key generation rate for a decoy-states-based system as a function of distance under the presence of simultaneous telecom traffic with different modulation techniques, and show a severe penalty growing with the number of classical channels present. Our results show that, for in-band coexistence, the telecom channels should be distributed as close as possible from the quantum channel to avoid the Raman noise peaks. Operation far from the zero dispersion wavelength of the fiber is also beneficial as it greatly reduces the generation of four-wave mixing inside the quantum channel. Furthermore, narrow spectral filtering on the quantum channels is required due to the harsh limitations of performing QKD under real telecom environments, with the quantum and several classical channels coexisting in the same ITU-T C-band.
Energy Technology Data Exchange (ETDEWEB)
Ankowski, A.; Graczyk, K.; Nowak, J.; Sobczyk, J. [Wroclaw University, Institute of Theoretical Physics, Wroclaw (Poland); Antonello, M.; Cavanna, F.; Piano Mortari, G.; Segreto, E. [Universita dell' Aquila, Gruppo collegato INFN and Dipartimento di Fisica, L' Aquila (Italy); Aprili, P.; Arneodo, F.; Palamara, O. [Laboratori Nazionali del Gran Sasso (LNGS) INFN, Assergi (Italy); Badertscher, A.; Ge, Y.; Laffranchi, M.; Messina, M.; Rubbia, A. [ETH Hoenggerberg, Institute for Particle Physics, Zuerich (Switzerland); Baiboussinov, B.; Baldo Ceolin, M.; Centro, S.; Gibin, D.; Guglielmi, A.; Meng, G.; Pietropaolo, F.; Varanini, F.; Ventura, S. [Universita di Padova and INFN, Dipartimento di Fisica, Padova (Italy); Battistoni, G.; Muraro, S.; Sala, P.R. [Universita di Milano and INFN, Dipartimento di Fisica, Milano (Italy); Benetti, P.; Borio di Tigliole, A.; Brunetti, R.; Calligarich, E.; De Vecchi, C.; Dolfini, R.; Gigli Berzolari, A.; Grandi, L.; Mauri, F.; Menegolli, A.; Montanari, C.; Piazzoli, A.; Prata, M.; Prata, M.C.; Przewlocki, P.; Rappoldi, A.; Raselli, G.L.; Rossella, M.; Rubbia, C.; Scannicchio, D.; Vignoli, C. [Universita di Pavia and INFN, Dipartimento di Fisica Nucleare e Teorica, Pavia (Italy); Bueno, A.; Carmona, M.C.; Garcia-Gamez, D.; Lozano, J.; Martinez de la Ossa, A.; Melgarejo, A.J.; Navas, S. [Universidad de Granada, Dept. de Fisica Teorica y del Cosmos and Centro Andaluz de Fisica de Particulas Elementales (CAFPE), Granada (Spain); Carbonara, F.; Cocco, A.G.; Di Cicco, A.; Ereditato, A.; Fiorillo, G.; Rossi, B. [Universita Federico II di Napoli and INFN, Dipt. di Scienze Fisiche, Napoli (Italy); Cennini, P.; Ferrari, A. [CERN, Geneve (Switzerland); Cesana, A.; Terrani, M. [Politecnico di Milano and INFN, Dipt. di Ingegneria Nucleare, Milano (Italy); Cline, D.B.; Lisowski, B.; Matthey, C.; Otwinowski, S.; Seo, Y.; Wang, H.; Yang, X. [Univ. of California, Dept. of Physics and Astronomy, Los Angeles, CA (United States)] [and others
2006-11-15
The ICARUS collaboration has demonstrated, following the operation of a 600 ton (T600) detector at shallow depth, that the technique based on liquid argon time projection chambers is now mature. The study of rare events, not contemplated in the standard model, can greatly benefit from the use of this kind of detectors. In particular, a deeper understanding of atmospheric neutrino properties will be obtained thanks to the unprecedented quality of the data ICARUS provides. However if we concentrate on the T600 performance, most of the {nu}{sub {mu}} charged current sample will be partially contained, due to the reduced dimensions of the detector. In this article, we address the problem of how well we can determine the kinematics of events having partially contained tracks. The analysis of a large sample of atmospheric muons collected during the T600 test run demonstrates that, in case the recorded track is at least one meter long, the muon momentum can be reconstructed by an algorithm that measures the multiple Coulomb scattering along the particle's path. Moreover, we show that momentum resolution can be improved by almost a factor two using an algorithm based on the Kalman filtering technique. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Dimakis, N; Mion, T [Department of Physics and Geology, University of Texas-Pan American, Edinburg, TX 78539 (United States); Bunker, G, E-mail: dimakis@utpa.ed [Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616 (United States)
2009-11-15
We present an accurate and efficient technique for calculating thermal X-ray absorption fine structure (XAFS) Debye-Waller factors (DWFs) applicable to crystalline materials. Using Density Functional Theory on a 3x3x3 supercell pattern of MnO structure, under the nonlocal hybrid B3LYP functional paired with Gaussian local basis sets, we obtain the normal mode eigenfrequencies and eigenvectors; these parameters are in turn used to calculate single and multiple scattering XAFS DWFs. The DWFs obtained via this technique are temperature dependent expressions and can be used to substantially reduce the number of fitting parameters, when experimental spectra are fitted with a hypothetical structure. The size of the supercell size limits the R-space range that these parameters could be used. Therefore corresponding DWFs for paths outside of this range are calculated using the correlated Debye model. Our method is compared with prior cluster calculations and with corresponding values obtained from fitting experimental XAFS spectra on manganosite with simulated spectra.
Mei, Jun; Liu, Zhengyou; Qiu, Chunyin
2005-06-29
We extend the multiple-scattering theory (MST) to out-of-plane propagating elastic waves in 2D periodical composites by taking into account the full vector character. The formalism for both the band structure calculation and the reflection and transmission coefficient calculation for finite slabs is presented. The latter is based on a double-layer scheme, which obtains the reflection and transmission matrix elements for the multilayer slab from those of a single layer. Being more rapid in both the band structure and the transmission coefficient calculations for out-of-plane propagating elastic waves, our approach especially shows great advantages in handling the systems with mixed solid and fluid components, for which the conventional plane wave approach fails. As the applications of the formalism, we calculate the band structure as well as the transmission coefficients through finite slabs for systems with lead rods in an epoxy host, steel rods in a water host and water rods in a PMMA host.
Energy Technology Data Exchange (ETDEWEB)
Yoshida, Hidetoshi; Naito, Osamu; Yamashita, Osamu; Kitamura, Shigeru; Hatae, Takaki; Nagashima, Akira [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment
1996-11-01
This article describes the design and operation of a 60 spatial channel Thomson scattering system as of 1996 with multiple ruby lasers to measure the electron temperature T{sub e} and density n{sub e} profiles of the JT-60U plasmas. The wide spectral range (403-683 nm) of the spectrometer and newly developed two-dimensional detector (high repetition photodiode array) has enabled this system to measure the high electron temperature plasma (5 keV or more) formed at the plasma core during negative magnetic shear discharge with high precision and reliability. The high spatial resolution (8 mm) have provided the precise measurement of steep electron temperature and density gradients formed at the plasma edge and in the scrape-off layer during H-mode discharge. The multilaser operation with the minimum time interval of 2 ms has provided an essential tool for the transient phenomenon measurement like the formation process of edge transport barrier during L- to H-mode transition and internal transport barrier during discharge with negative magnetic shear, the relaxation process of pellet injected plasma and so on. Measurement examples of recent JT-60U T{sub e} and n{sub e} profiles are also presented. (author)
Barborica, A.; Mihailescu, I. N.; Teodorescu, V. S.
1994-03-01
We introduce a theoretical analysis of the temporal and spatial evolution of the surface topography of solids following interference between incident and scattered pulsed laser beams. The essential role played by the nonlinear delayed feedback in the laser-radiation-surface system is considered. We show that it finally determines the surface topography evolution from pulse to pulse. In order to complete the analysis, numerical calculations have been conducted under the hypothesis of strong attenuation of laser radiation into the sample and of a limited heat diffusion during the action of a laser pulse. We predict an evolution from very simple to complex (chaotic) structures under multiple-pulse-laser irradiation of solid surfaces. This evolution is determined by some key irradiation parameters; initial surface microrelief, incident laser intensity, and the number of applied laser pulses. Experiments were performed in order to check the main predictions of the theoretical analysis. The system of transversal excited atmospheric pressure-CO2 laser radiation (λ=10.6 μm)-interacting with fused silica was chosen as appropriate for performing test experiments. Optical microscopy studies of laser-treated zones evidenced special modifications of the surface topography in good accordance with the conclusions following from the theoretical analysis. The theoretical analysis is also in good agreement with some available data from the literature, at the same time providing a coherent interpretation of previously unexplained behaviors.
Correlation-based virtual source imaging in strongly scattering random media
Garnier, Josselin; Papanicolaou, George
2012-07-01
Array imaging in a strongly scattering medium is limited because coherent signals recorded at the array and coming from a reflector to be imaged are weak and dominated by incoherent signals coming from multiple scattering by the medium. If, however, an auxiliary passive array can be placed between the reflector to be imaged and the scattering medium then the cross correlations of the incoherent signals on this array can also be used to image the reflector. In this paper, we show both in the weakly scattering paraxial regime and in strongly scattering layered media that this cross-correlation approach produces images as if the medium between the sources and the passive array was homogeneous and the auxiliary passive array was an active one made up of both sources and receivers.
Minato, Shohei; Ghose, Ranajit
2017-03-01
Low-frequency, axially-symmetric guided waves which propagate along a fluid-filled borehole (tube waves) are studied in order to characterize the hydraulic fractures intersecting the borehole. We formulate a new equation for the total tube wavefield, which includes simultaneous effects of (1) tube-wave scattering (reflection and transmission) due to wave propagation across hydraulic fractures, and (2) tube-wave generation due to incident plane P waves. The fracture is represented by the nonwelded interface boundary conditions. We use an appropriate form of the representation theorem in order to correctly handle the multiple scattering due to nonwelded interfaces. Our approach can implement any model that has so far been developed. We consider a recent model which includes simultaneous effects of fluid viscosity, dynamic fluid flow, and fracture compliance. The derived equation offers a number of important insights. We recognize that the effective generation amplitude contains the simultaneous effect of both tube-wave generation and scattering. This leads to a new physical understanding indicating that the tube waves are scattered immediately after generation. We show that this scattering is nonlinear with respect to interface compliance. This physical mechanism can be implicitly accounted for by considering more realistic boundary conditions. We also illustrate the application of the new equation in order to predict the complex signature of the total tube wavefield, including generation and scattering at multiple hydraulic fractures. A new formulation for focusing analyses is also derived in order to image and characterize the hydraulic fractures. The obtained results and discussions are important for interpretation, modeling, and imaging using low-frequency guided waves, in the presence of multiple fractures along a cylindrical inclusion.
Directory of Open Access Journals (Sweden)
Shinichi Kinugasa
2012-01-01
Full Text Available Accurate determination of the intensity-average diameter of polystyrene latex (PS-latex by dynamic light scattering (DLS was carried out through extrapolation of both the concentration of PS-latex and the observed scattering angle. Intensity-average diameter and size distribution were reliably determined by asymmetric flow field flow fractionation (AFFFF using multi-angle light scattering (MALS with consideration of band broadening in AFFFF separation. The intensity-average diameter determined by DLS and AFFFF-MALS agreed well within the estimated uncertainties, although the size distribution of PS-latex determined by DLS was less reliable in comparison with that determined by AFFFF-MALS.
Shea, Jacob D.; Kosmas, Panagiotis; Hagness, Susan C.; Van Veen, Barry D.
2010-01-01
Purpose: Breast density measurement has the potential to play an important role in individualized breast cancer risk assessment and prevention decisions. Routine evaluation of breast density will require the availability of a low-cost, nonionizing, three-dimensional (3-D) tomographic imaging modality that exploits a strong properties contrast between dense fibroglandular tissue and less dense adipose tissue. The purpose of this computational study is to investigate the performance of 3-D tomography using low-power microwaves to reconstruct the spatial distribution of breast tissue dielectric properties and to evaluate the modality for application to breast density characterization. Methods: State-of-the-art 3-D numerical breast phantoms that are realistic in both structural and dielectric properties are employed. The test phantoms include one sample from each of four classes of mammographic breast density. Since the properties of these phantoms are known exactly, these testbeds serve as a rigorous benchmark for the imaging results. The distorted Born iterative imaging method is applied to simulated array measurements of the numerical phantoms. The forward solver in the imaging algorithm employs the finite-difference time-domain method of solving the time-domain Maxwell’s equations, and the dielectric profiles are estimated using an integral equation form of the Helmholtz wave equation. A multiple-frequency, bound-constrained, vector field inverse scattering solution is implemented that enables practical inversion of the large-scale 3-D problem. Knowledge of the frequency-dependent characteristic of breast tissues at microwave frequencies is exploited to obtain a parametric reconstruction of the dispersive dielectric profile of the interior of the breast. Imaging is performed on a high-resolution voxel basis and the solution is bounded by a known range of dielectric properties of the constituent breast tissues. The imaging method is validated using a breast
García, H. A.; Iriarte, D. I.; Pomarico, J. A.; Grosenick, D.; Macdonald, R.
2017-03-01
Functional analysis of the human brain requires methods that take the layered structure of the head into account. In this work we introduce an improved theoretical model that describes light propagation in multilayered, turbid cylinders with a infinitely thick bottom layer, which simplifies calculations and reduces computation times. Our approach was validated with Monte Carlo simulations and single distance, time-resolved experiments on a three-layered phantom, where the absorption of the deepest layer was gradually modified. We were able to retrieve both, the scattering and absorption coefficient of this layer within reasonable errors. Hereby, changes in scattering were found to have less effect on the experimental data than absorption changes, making the reliable estimation of the reduced scattering coefficient more difficult in comparison to absorption. Stability of the implemented fitting routine was thoroughly analyzed, revealing that special care is needed to obtain accurate values for the reduced scattering coefficient.
Quantum Optical Multiple Scattering
DEFF Research Database (Denmark)
Ott, Johan Raunkjær
interference survives even after disorder averaging. The quantum interference manifests itself through increased photon correlations. Furthermore, the theoretical description of a measurement procedure is presented. In this work we relate the noise power spectrum of the total transmitted or reflected light......-state population and fluorescence spectrum, where we find cooperative effects in both the elastic and the inelastic spectra....
Energy Technology Data Exchange (ETDEWEB)
Nisbet, A. G. A., E-mail: gareth.nisbet@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, OX11 0DE (United Kingdom); Beutier, G. [CNRS, SIMAP, F-38000 Grenoble (France); Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble (France); Fabrizi, F.; Moser, B.; Collins, S. P. [Diamond Light Source, Harwell Science and Innovation Campus, OX11 0DE (United Kingdom)
2015-01-01
A new form of diffraction lines similar to Rutherford, Kikuchi and Kossel lines has been identified. They can be used to eliminate the need for sample/source matching in Lonsdale’s triple convergent line method in lattice-parameter determination. A new form of diffraction lines has been identified, similar to Rutherford, Kikuchi and Kossel lines. This paper highlights some of the properties of these lines and shows how they can be used to eliminate the need for sample/source matching in Lonsdale’s triple convergent line method in lattice-parameter determination.
Wang, R; Li, X A; Yu, C X
2000-08-01
The purpose of this work is to evaluate the EGS4/PRESTA electron multiple-scattering (MS) algorithms for dose calculation in intravascular brachytherapy (IVBT) using a 90Sr/90Y source. The small source size and the small volume of interest in IVBT require very fine spatial resolution, which may break down the constraints of Molière's MS theory as implemented in EGS4. The theory is accurate only when the electron step sizes are large enough to allow the number of collisions omega0 to be much greater than e = 2.7183. When step sizes are too small to allow at least 2.7183 collisions, as may be necessitated by the fine geometry, the algorithm may switch off MS, producing dosimetric artefacts. This study showed that switching off MS could produce a dose deviation of up to 6% when the half-thickness (d/2) of the dose scoring region is comparable with the Moliere minimum step size (t(min) = 2.7183). The effect of switching off MS is negligible if d/2 > t(min) For the case of omega0 > e, if the electron step sizes are chosen to allow five to 40 collisions, with increasing step size, the doses surrounding the source increase and the error decreases. On the other hand, when larger step sizes are chosen, the dose calculation voxel size must also be increased in order for the calculations to converge. A good compromise between accuracy and applicability for IVBT simulation can be made, if the thickness of the scoring region is 0.1 mm and the electron step sizes are in the range allowing 10 to 30 collisions.
Isospin effects in elastic proton-nucleus scattering
Chinn, C. R.; Elster, Ch.; Thaler, R. M.
1993-05-01
Isovector effects in proton-nucleus elastic scattering at medium energies are studied. The accuracy of the Kerman-McManus-Thaler isospin averaging procedure is found to be very good for nuclei larger than 4He. Studies of 40Ca and 208Pb suggest that the surface neutrons may be pulled in somewhat relative to the protons, although uncertainties in the detailed applicability of the present truncation of the multiple scattering treatment render firm conclusions premature.
Isospin effects in elastic proton-nucleus scattering
Energy Technology Data Exchange (ETDEWEB)
Chinn, C.R. (Service de Physique et Techniques Nucleaires, Centre d' Etudes de Bruyeres-le-Chatel, B.P. No. 12, 91680 Bruyeres-le-Chatel (France)); Elster, C. (Institute of Nuclear and Particle Physics and Department of Physics, Ohio University, Athens, Ohio 45701 (United States)); Thaler, R.M. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States) Case Western Reserve University, Cleveland, Ohio 44106 (United States))
1993-05-01
Isovector effects in proton-nucleus elastic scattering at medium energies are studied. The accuracy of the Kerman-McManus-Thaler isospin averaging procedure is found to be very good for nuclei larger than [sup 4]He. Studies of [sup 40]Ca and [sup 208]Pb suggest that the surface neutrons may be pulled in somewhat relative to the protons, although uncertainties in the detailed applicability of the present truncation of the multiple scattering treatment render firm conclusions premature.
Energy Technology Data Exchange (ETDEWEB)
Ibraeva, E. T., E-mail: ibraeva.elena@gmail.com [National Nuclear Center of Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Imambekov, O. [Al-Farabi Kazakh National University (Kazakhstan)
2015-07-15
Differential cross sections for elastic p{sup 6,8}He and p{sup 8,9}Li scattering at energies between 60 and 70 MeV per nucleon and at the energy of 700 MeV per nucleon were calculated. The calculations in question were performed with the wave functions found on the basis of the α–n–n (for {sup 6}He), α–t–n (for {sup 8}Li), and α–t–2n (for {sup 9}Li) three-body models and with the density from the large-scale shell model for the {sup 8}He nucleus. The respective matrix elements were derived either upon taking fully into account the multiple-scattering operator or in the optical-limit approximation. A comparison of the results of the precise and approximate calculations made it possible to estimate reliably the contribution of higher multiplicity collisions to the differential cross sections.
Chukhovskii, F N; Roshchin, B S
2015-11-01
Based on the rigorous Green function formalism to describe the grazing-incidence small-angle X-ray scattering (GISAXS) problem, a system of two linked integral equations is derived with respect to amplitudes of the reflected and transmitted plane q-eigenwaves (eigenstate functions) propagating through two homogeneous media separated from each other by a rough surface interface. To build up the coupled solutions of these basic equations beyond the perturbation theory constraint 2kσθ0 < 1, a simple iteration procedure is proposed as opposed to the self-consistent wave approach [Chukhovskii (2011). Acta Cryst. A67, 200-209; Chukhovski (2012). Acta Cryst. A68, 505-512]. Using the first-order iteration, analytical expressions for the averaged specular and non-specular scattering intensity distributions have been obtained. These expressions are further analysed in terms of the GISAXS parameters {k, θ, θ0} and surface finish ones {σ, l, h}, where θ and θ0 are the scattering and incidence angles of the X-rays, respectively, σ is the root-mean-square roughness, l is the correlation length, h is the fractal surface model index, k = 2π/λ, and λ is the X-ray wavelength. A direct way to determine the surface finish parameters from the experimental specular and diffuse scattering indicatrix scan data is discussed for an example of GISAXS measurements from rough surfaces of α-quartz and CdTe samples.
Directory of Open Access Journals (Sweden)
A. O. Langford
2007-01-01
Full Text Available The "filling-in" (FI of Fraunhofer lines, often referred to as the Ring effect, was examined using measurements of near ultraviolet sunlight scattered from the zenith sky above Boulder, Colorado during July and August 2005. The FI of the 344.1 nm Fe I line was directly determined by comparing direct sun and cloud-free zenith sky spectra recorded on the same day. The results, obtained over solar zenith angles (SZA from 20° to 70°, are compared to the predictions of a simple rotational Raman Scattering (RRS spectral model. The measured FI was found to be up to 70% greater than that predicted by first-order molecular scattering with a much stronger SZA dependence. Simultaneously measured aerosol optical depths and Monte Carlo calculations show that the combination of aerosol scattering and second-order molecular scattering can account for these differences, and potentially explain the contradictory SZA dependences in previously published measurements of FI. These two scattering processes also introduce a wavelength dependence to FI that complicates the fitting of diffuse sunlight observations in differential optical absorption spectroscopy (DOAS. A simple correction to improve DOAS retrievals by removing this wavelength dependence is described.
Rauf, M.A.
2015-01-01
This study presents an investigation conducted on HRM within SMEs to determine HRM effectivity in both the readymade garments manufacturers and exporters industry of Lahore, Pakistan, and SMEs from multiple industries in the Netherlands. This study has attempted to contribute to contemporary
Rauf, M.A.
2015-01-01
This study presents an investigation conducted on HRM within SMEs to determine HRM effectivity in both the readymade garments manufacturers and exporters industry of Lahore, Pakistan, and SMEs from multiple industries in the Netherlands. This study has attempted to contribute to contemporary researc
Rauf, M.A.
2015-01-01
This study presents an investigation conducted on HRM within SMEs to determine HRM effectivity in both the readymade garments manufacturers and exporters industry of Lahore, Pakistan, and SMEs from multiple industries in the Netherlands. This study has attempted to contribute to contemporary researc
Rauf, M. A.
2015-01-01
This study presents an investigation conducted on HRM within SMEs to determine HRM effectivity in both the readymade garments manufacturers and exporters industry of Lahore, Pakistan, and SMEs from multiple industries in the Netherlands. This study has attempted to contribute to contemporary research with regard to how HRM alignment and HRM effectivity in SMEs can best be measured. This is done by investigating SME’s HR practices to measure HRM alignments and HRM outcomes in order to determin...
Directory of Open Access Journals (Sweden)
T. R. Robinson
Full Text Available A new theory of the propagation of low power electromagnetic test waves through the upper-hybrid resonance layer in the presence of magnetic field-aligned plasma density striations, which includes the effects of multiple scatter, is presented. The case of sinusoidal striations in a cold magnetoplasma is treated rigorously and then extended, in an approximate manner, to the broad-band striation spectrum and warm plasma cases. In contrast to previous, single scatter theories, it is found that the interaction layer is much broader than the wavelength of the test wave. This is due to the combined electric fields of the scattered waves becoming localised on the contour of a fixed plasma density, which corresponds to a constant value for the local upper-hybrid resonance frequency over the whole interaction region. The results are applied to the calculation of the refractive index of an ordinary mode test wave during modification experiments in the ionospheric F-region. Although strong anomalous absorption arises, no new cutoffs occur at the upper-hybrid resonance, so that in contrast to the predictions of previous single scatter theories, no additional reflections occur there. These results are consistent with observations made during ionospheric modification experiments at Tromsø, Norway.
Key words. Ionosphere (active experiments; ionospheric irregularities Radio science (ionospheric propagation
Ikegami, Seiji
2017-09-01
The switching model (PSM) developed in the previous paper is extended to obtain an ;extended switching model (ESM). In the ESM, the mixt electronic-and-nuclear energy-loss region, in addition to the electronic and nuclear energy-loss regions in PSM, is taken into account analytically and appropriately. This model is combined with a small-angle multiple scattering range theory considering both nuclear and electronic stopping effects developed by Marwick-Sigmund and Valdes-Arista to formulate a improved range theory. The ESM is also combined with the multiple scattering theory with non-small angle approximation by Goudsmit-Saunderson. Furthermore, we applied ESM to lateral spread model of Marwick-Sigmund. Numerical calculations of the entire distribution functions including one of the mixt region are roughly and approximately possible. However, exact numerical calculation may be impossible. Consequently, several preliminary numerical calculations of the electronic, mixt, and nuclear regions are performed to examine their underlying behavior with respect to the incident energy, the scattering angle, the outgoing projectile intensity, and the target thickness. We show the numerical results not only of PSM and but also of ESM. Both numerical results are shown in the present paper for the first time. Since the theoretical relations are constructed using reduced variables, the calculations are made only on the case of C colliding on C.
Institute of Scientific and Technical Information of China (English)
曹松; 唐景昌; 沈少来; 陈更生; 马丹
2003-01-01
We use the multiple-scattering cluster method to calculate the sulphur 1s near-edge x-ray absorption fine structure (NEXAFS) of S-passivated InP(100) surface. The physical origins of the resonances in the NEXAFS have been unveiled. It is shown that the most important resonance is attributed to the photoelectron scattering between the central sulphur and the nearest indium atoms. The studies show that two S-S dimers with the bond lengths of 2.05 A and 3.05 A coexist in the surface, meanwhile the bridge and antibridge site adsorption of single S could not be ruled out. We support the scanning tunnelling microscopy result that the S-passivated InP(100) surface exhibits significant disorder.
Taratin, AM; Chesnokov, Yu A; Denisov, A S; Dalpiaz, P; Bagli, E; Taratin, A M; Lapina, L P; Vavilov, S A; Fiorini, M; Vallazza, E; Afonin, A G; Guidi, V; Baricordi, S; Prest, M; Kovalenko, A D; Skorobogatov, V V; Scandale, W; Golovatyukh, V M; Suvorov, V M; Maisheev, V A; Vincenzi, D; Ivanov, Yu M; Hasan, S; Bolognini, D; Yazynin, I A; Della Mea, Gianantonio; Mazzolari, A; Gavrikov, Yu A; Vomiero, A; Milan, R
2010-01-01
Different kinds of deflection in a silicon crystal bent along the (111) axis was observed for 150 GeV/c negative particles. mainly pi(-) mesons, at one of the secondary beams of the CERN SPS. The whole beam was deflected to one side in quasi-bound states of doughnut scattering (DSB) by atomic strings with the efficiency (95.4 +/- 0.2)\\% and with the peak position close to the bend crystal angle, alpha = 185 mu rad. It was observed volume capture of pi(-) mesons into the DSB states with a probability higher than 7\\%. A beam deflection opposite to the crystal bend was observed for some orientations of the crystal axis due to doughnut scattering and subsequent multiple volume reflections of pi(-) mesons by different bent planes crossing the axis. (C) 2010 Elsevier B.V. All rights reserved.
Calvet, Marie
2008-01-01
We propose to model the uppermost inner core as an aggregate of randomly oriented anisotropic ``patches''. A patch is defined as an assemblage of a possibly large number of crystals with identically oriented crystallographic axes. This simple model accounts for the observed velocity isotropy of short period body waves, and offers a reasonable physical interpretation for the scatterers detected at the top of the inner core. From rigorous multiple scattering modeling of seismic wave propagation through the aggregate, we obtain strong constraints on both the size and the elastic constants of iron patches. We perform a systematic search for iron models compatible with measured seismic velocities and attenuations. An iron model is characterized by its symmetry (cubic or hexagonal), elastic constants, and patch size. Independent of the crystal symmetry, we infer a most likely size of patch of the order of 400 m. Recent {\\it bcc} iron models from the literature are in very good agreement with the most probable elast...
Indian Academy of Sciences (India)
A Madhulatha; John P George; E N Rajagopal
2017-03-01
Incorporation of cloud- and precipitation-affected radiances from microwave satellite sensors in data assimilation system has a great potential in improving the accuracy of numerical model forecasts over the regions of high impact weather. By employing the multiple scattering radiative transfer model RTTOVSCATT,all-sky radiance (clear sky and cloudy sky) simulation has been performed for six channel microwave SAPHIR (Sounder for Atmospheric Profiling of Humidity in the Inter-tropics by Radiometry) sensors of Megha-Tropiques (MT) satellite. To investigate the importance of cloud-affected radiance data in severe weather conditions, all-sky radiance simulation is carried out for the severe cyclonic storm ‘Hudhud’ formed over Bay of Bengal. Hydrometeors from NCMRWF unified model (NCUM) forecasts are used as input to the RTTOV model to simulate cloud-affected SAPHIR radiances. Horizontal and vertical distribution of all-sky simulated radiances agrees reasonably well with the SAPHIR observed radiancesover cloudy regions during different stages of cyclone development. Simulated brightness temperatures of six SAPHIR channels indicate that the three dimensional humidity structure of tropical cyclone is well represented in all-sky computations. Improved correlation and reduced bias and root mean squareerror against SAPHIR observations are apparent. Probability distribution functions reveal that all-sky simulations are able to produce the cloud-affected lower brightness temperatures associated with cloudy regions. The density scatter plots infer that all-sky radiances are more consistent with observed radiances.Correlation between different types of hydrometeors and simulated brightness temperatures at respective atmospheric levels highlights the significance of inclusion of scattering effects from different hydrometeors in simulating the cloud-affected radiances in all-sky simulations. The results are promisingand suggest that the inclusion of multiple scattering
Madhulatha, A.; George, John P.; Rajagopal, E. N.
2017-03-01
Incorporation of cloud- and precipitation-affected radiances from microwave satellite sensors in data assimilation system has a great potential in improving the accuracy of numerical model forecasts over the regions of high impact weather. By employing the multiple scattering radiative transfer model RTTOV-SCATT, all-sky radiance (clear sky and cloudy sky) simulation has been performed for six channel microwave SAPHIR (Sounder for Atmospheric Profiling of Humidity in the Inter-tropics by Radiometry) sensors of Megha-Tropiques (MT) satellite. To investigate the importance of cloud-affected radiance data in severe weather conditions, all-sky radiance simulation is carried out for the severe cyclonic storm `Hudhud' formed over Bay of Bengal. Hydrometeors from NCMRWF unified model (NCUM) forecasts are used as input to the RTTOV model to simulate cloud-affected SAPHIR radiances. Horizontal and vertical distribution of all-sky simulated radiances agrees reasonably well with the SAPHIR observed radiances over cloudy regions during different stages of cyclone development. Simulated brightness temperatures of six SAPHIR channels indicate that the three dimensional humidity structure of tropical cyclone is well represented in all-sky computations. Improved correlation and reduced bias and root mean square error against SAPHIR observations are apparent. Probability distribution functions reveal that all-sky simulations are able to produce the cloud-affected lower brightness temperatures associated with cloudy regions. The density scatter plots infer that all-sky radiances are more consistent with observed radiances. Correlation between different types of hydrometeors and simulated brightness temperatures at respective atmospheric levels highlights the significance of inclusion of scattering effects from different hydrometeors in simulating the cloud-affected radiances in all-sky simulations. The results are promising and suggest that the inclusion of multiple scattering
Microscopic formulation of medium contributions to the first-order optical potential
Chinn, C. R.; Elster, Ch.; Thaler, R. M.
1993-12-01
A refinement of the first-order optical potential is introduced, consistent with multiple scattering theory and the spectator expansion. A systematic formalism is presented to treat medium contributions associated with the difference between the effective NN t matrix as required by multiple scattering theory and the free NN t matrix. A mean field potential is used to represent the action of the residual (A-1) nucleus upon the struck target nucleon (medium effects). We calculate elastic proton and neutron scattering from 40Ca, using the full Bonn interaction and two different mean field potentials taken from realistic and proven nuclear structure models. Results indicate that the medium contributions are insignificant at energies above 300 MeV and provide a significant improvement of the theoretical predictions for laboratory energies between 48 and 200 MeV.
Microscopic formulation of medium contributions to the first-order optical potential
Energy Technology Data Exchange (ETDEWEB)
Chinn, C.R. (Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States) Center for Computationally Intensive Physics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)); Elster, C. (Institute of Nuclear and Particle Physics and Department of Physics, Ohio University, Athens, Ohio 45701 (United States)); Thaler, R.M. (Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States) Case Western Reserve University, Cleveland, Ohio 44106 (United States))
1993-12-01
A refinement of the first-order optical potential is introduced, consistent with multiple scattering theory and the spectator expansion. A systematic formalism is presented to treat medium contributions associated with the difference between the effective [ital NN] [ital t] matrix as required by multiple scattering theory and the free [ital NN] [ital t] matrix. A mean field potential is used to represent the action of the residual ([ital A][minus]1) nucleus upon the struck target nucleon (medium effects). We calculate elastic proton and neutron scattering from [sup 40]Ca, using the full Bonn interaction and two different mean field potentials taken from realistic and proven nuclear structure models. Results indicate that the medium contributions are insignificant at energies above 300 MeV and provide a significant improvement of the theoretical predictions for laboratory energies between 48 and 200 MeV.
Institute of Scientific and Technical Information of China (English)
张梅; 林林; 高应俊; 罗云瀚
2012-01-01
A method of coherent measuring optical parameters of scattering medium is presented based on Monte Carlo simulation. The condensed scaling method is introduced to accelerating process of calculation. A tri-layer structure BP-artificial neural network is developed for reverse calculation of scattering and absorption coefficients of medium. Fat emulsion and stain mixture of IntralipidTM and India ink are taken as scattering and absorbing sample for coherent measurement by fiber Michelson interferometer. Results of experiments show the linear relation between scattering or absorption coefficients and concentration of IntralipidTM or India ink. The method is helpful to nondestructive testing components of turbid material.%提出了一种散射介质光学参量的干涉测量方法.在蒙特卡罗数值模拟的基础上引入聚焦高斯光源模型和基于比例缩放的压缩算法,实现了对光子后向散射分布和干涉特性的快速模拟.利用计算数据训练了前向人工神经网络进行了介质光学参量的反向求解.实验中以脂肪乳注射剂和生物染色剂印度墨水组成的悬混液为样本,通过光学干涉系统测量得到了后向散射光依赖于深度的干涉光强分布,并对其中散射和吸收系数进行了反向计算.所得结果能够正确反映散射和吸收系数与散射和吸收物质浓度之间的线性关系,验证了该方法的可行性.
Yan, Yu-Liang; Li, Xiao-Mei; Zhou, Dai-Mei; Cheng, Yun; Dong, Bao-Guo; Cai, Xu; Sa, Ben-Hao
2015-01-01
We employed the PYTHIA 6.4 model and the extended parton and hadron cascade model PACIAE 2.2 to comparatively investigate the DIS normalized specific charged hadron multiplicity in the 27.6 GeV electron semi-inclusive deep-inelastic scattering off proton and deuteron. The PYTHIA and PACIAE results calculated with default model parameters not well and fairly well reproduce the corresponding HERMES data, respectively. In addition, we have discussed the effects of the differences between the PYTHIA and PACIAE models.
Abbiendi, G; Abramowicz, H; Acosta, D; Adamczyk, L; Adamus, M; Ahn, S H; Amelung, C; An Shiz Hong; Anselmo, F; Antonioli, P; Arneodo, M; Bacon, Trevor C; Badgett, W F; Bailey, D C; Bailey, D S; Bamberger, A; Barbagli, G; Bari, G; Barreiro, F; Barret, O; Bashindzhagian, G L; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Beier, H; Bellagamba, L; Bertolin, A; Bhadra, S; Bienlein, J K; Blaikley, H E; Bohnet, I; Bokel, C; Bornheim, A; Borzemski, P; Boscherini, D; Botje, M; Breitweg, J; Brock, I; Bromley, J T; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Burgard, C; Burow, B D; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carlin, R; Cartiglia, N; Cashmore, R J; Castellini, G; Catterall, C D; Chapin, D; Chekanov, S; Chwastowski, J; Ciborowski, J; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Coboken, K; Coldewey, C; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Cottingham, W N; Crittenden, J; Cross, R; D'Agostini, G; Dagan, S; Dal Corso, F; Dardo, M; De Pasquale, S; Deffner, R; Deppe, O; Derrick, M; Deshpande, Abhay A; Desler, K; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Dosselli, U; Doyle, A T; Drews, G; Dulinski, Z; Durkin, L S; Dusini, S; Eckert, M; Edmonds, J K; Eisenberg, Y; Eisenhardt, S; Engelen, J; Epperson, D E; Ermolov, P F; Eskreys, Andrzej; Fagerstroem, C P; Fernández, J P; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fox-Murphy, A; Fricke, U; Frisken, W R; Fusayasu, T; Gadaj, T; Galea, R; Gallo, E; García, G; Garfagnini, A; Gendner, N; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Glasman, C; Göbel, F; Golubkov, Yu A; Göttlicher, P; Grabosch, H J; Graciani, R; Grosse-Knetter, J; Grzelak, G; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanna, D S; Harnew, N; Hart, J C; Hartmann, H; Hartmann, J; Hartner, G F; Hasell, D; Hayes, M E; Heaphy, E A; Heath, G P; Heath, H F; Hebbel, K; Heinloth, K; Heinz, L; Hernández, J M; Heusch, C A; Hilger, E; Hirose, T; Hochman, D; Holm, U; Homma, K; Hong, S J; Howell, G; Hughes, V W; Iacobucci, G; Iannotti, L; Iga, Y; Inuzuka, M; Ishii, T; Jakob, H P; Jelen, K; Jeoung, H Y; Jing, Z; Johnson, K F; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Kasemann, M; Katz, U F; Kcira, D; Kerger, R; Khakzad, M; Khein, L A; Kim, C L; Kim, J Y; Kisielewska, D; Kitamura, S; Klanner, Robert; Klimek, K; Koch, W; Koffeman, E; Kooijman, P; Koop, T; Korotkova, N A; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowalski, H; Kowalski, T; Krakauer, D; Kreisel, A; Kuze, M; Kuzmin, V A; Labarga, L; Lamberti, L; Lane, J B; Laurenti, G; Lee, J H; Lee, S B; Lee, S W; Levi, G; Levman, G M; Levy, A; Lim, H; Lim, I T; Limentani, S; Lindemann, L; Ling, T Y; Liu, W; Löhr, B; Lohrmann, E; Long, K R; Lopez-Duran Viani, A; Lukina, O Yu; Ma, K J; Maccarrone, G; MacDonald, N; Magill, S; Mallik, U; Margotti, A; Marini, G; Markun, P; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Mattingly, M C K; Mattingly, S E K; McCance, G J; McCubbin, N A; McFall, J D; Mellado, B; Menary, S; Meyer, A; Meyer-Larsen, A; Milewski, J; Milite, M; Miller, D B; Monaco, V; Mönig, K; Monteiro, T; Morandin, M; Moritz, M; Murray, W N; Musgrave, B; Nagano, K; Nam, S W; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Noyes, V A; Nylander, P; Ochs, A; Oh, B Y; Okrasinski, J R; Olkiewicz, K; Orr, R S; Pac, M Y; Padhi, S; Palmonari, F; Park, I H; Park, S K; Parsons, J A; Paul, E; Pavel, N; Pawlak, J M; Pawlak, R; Pelfer, Pier Giovanni; Pellegrino, A; Pelucchi, F; Peroni, C; Pesci, A; Petrucci, M C; Pfeiffer, M; Piccioni, D; Piotrzkowski, K; Poelz, G; Polenz, S; Polini, A; Posocco, M; Prinias, A; Proskuryakov, A S; Przybycien, M B; Puga, J; Quadt, A; Raach, H; Raso, M; Rautenberg, J; Redondo, I; Reeder, D D; Repond, J; Ritz, S; Riveline, M; Rohde, M; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Sadrozinski, H F W; Salehi, H; Sampson, S; Sartorelli, G; Saull, P R B; Savin, A A; Saxon, D H; Schechter, A; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Schwarzer, O; Sciulli, F; Scott, J; Sedgbeer, J K; Seiden, A; Selonke, F; Shah, T P; Shcheglova, L M; Sideris, D; Sievers, M; Simmons, D; Sinclair, L E; Skillicorn, I O; Smalska, B; Smith, W H; Solano, A; Solomin, A N; Son, D; Saint-Laurent, M G; Staiano, A; Stairs, D G; Stanco, L; Stanek, R; Stifutkin, A; Stonjek, S; Straub, P B; Strickland, E; Stroili, R; Susinno, G; Suszycki, L; Sutton, M R; Suzuki, I; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Toothacker, W S; Tsurugai, T; Tuning, N; Tymieniecka, T; Umemori, K; Vaiciulis, A W; Velthuis, J J; Verkerke, W; Voci, C; Vossebeld, Joost Herman; Votano, L; Walczak, R; Walker, R; Wang, S M; Waters, D S; Waugh, R; Weber, A; Westphal, D; Whitmore, J J; Wichmann, R; Wick, K; Wieber, H; Wiggers, L; Wildschek, T; Williams, D C; Wills, H H; Wing, M; Wodarczyk, M; Wolf, G; Wölfle, S; Wollmer, U; Wróblewski, A K; Yamada, S; Yamashita, T; Yamauchi, K; Yamazaki, Y; Yoshida, R; Youngman, C; Zajac, J; Zakrzewski, J A; Zamora Garcia, Y; Zawiejski, L; Zetsche, F; Zeuner, W; Zhu, Q; Zichichi, Antonino; Zotkin, S A; De Wolf, E; Del Peso, J; Van Sighem, A
1999-01-01
Charged particle production in neutral current deep inelastic scattering (DIS) has been studied using the ZEUS detector.The evolution of the mean multiplicities, scaled momenta and transverse momenta in Q^2 and x for $10 6\\times 10^{-4}$ has been investigated in the current and target fragmentation regions of the Breit frame. Distributions in the target region, using HERA data for the first time, are compared to distributions in the current region. Predictions based on MLLA and LPHD are inconsistent with the data.
Gamma-ray scatter methods applied to industrial measurement systems
Energy Technology Data Exchange (ETDEWEB)
Holstad, Marie Bueie
2004-09-01
Throughout the work presented in this dissertation it has been confirmed that the use of scattered gamma-radiation is a complex but useful tool in industrial measurement science. Scattered radiation has shown to be useful both when traditional measurement principles cannot be used (Chapter 4) and when more information about a system is needed than what is obtained with transmission measurements (Chapter 6). All three main projects (Chapters 4, 5 and 6) confirm that the sensitivity and accuracy of systems based on scattered gamma-radiation depends strongly on the geometry of the setup and that that presence of multiple scattered radiation makes the problems complex. Chapter 4 shows that multiple scattered gamma-radiation can be used for detection of changes in density where the dimensions are too large to use transmitted radiation. There is, however, an upper limit on the thickness of the absorbing medium also when scattered radiation is utilized. As seen in Chapter 5, multiple scattered gamma-radiation can in principle also be used in level gauges with very compact measurement geometries. The main challenges are the sensitivity to interfaces between materials with similar densities and low count rate. These challenges could not be overcome for level measurements in gravitational separator tanks. The results presented in Chapter 6 show that it is feasible to combine transmission and scatter measurements to characterize produced water in the oil and gas industry. (Author)
Energy Technology Data Exchange (ETDEWEB)
Frey, E.C.; Tsui, B.M.W. [Univ. of North Carolina, Chapel Hill, NC (United States)
1994-05-01
Conventional wisdom has been that scattered photons contain no useful information and should be removed from the projection data. However, inspection of the scatter response function (SRF) shows that it has a sharply peaked component, indicating that scattered photons do carry some spatial information. In this work we demonstrate that, combined with iterative reconstruction methods and an accurate model of the SRF, this information can be useful in improving SPECT image quality. We have extended a previously described method for estimating the spatially variant SRF, slab derived scatter estimation (SDSE), to lower energy windows. The method was verified by comparison with MC simulated projection data. Noise-free projection data were simulated using SDSE for a 140 keV primary energy window and stored din seven consecutive 7 keV wide energy windows spanning the range 105-154KeV and a conventional 20% wide photopeak window (126-154 keV). First the data from each energy window were reconstructed using iterative reconstruction methods and a projector-backprojector modeling only attenuation and collimator-detector response. In this case the image quality decreases with decreasing energy, with the images from the lowest energy windows having very poor quality. Similarly, images were reconstructed using interative reconstruction methods and a projector-backprojector modeling the SRF in each energy window. While the images form the lower energy windows are still poorer, the image features are clearly recognizable. This indicates that the data from the lower energy window contain useful information which, if properly modeled, can be recovered. Finally, we reconstructed an image simultaneously from all of the 7 keV wide energy windows using iterative reconstruction methods.
Titovich, Alexey S
2014-01-01
A thin infinitely long elastic shell is stiffened by $J$ in number identical lengthwise ribs distributed uniformly around the circumference and joined to a rod in the center. The 2D model of the substructure is a rigid central mass supported by $J$ axisymmetrically placed linear springs. The response of the shell-spring-mass system is quite different from a fluid filled shell or that of a solid cylinder due to the discrete number of contact points which couple the displacement of the shell at different locations. Exterior acoustic scattering due to normal plane wave incidence is solved in closed form for arbitrary $J$. The scattering matrix associated with the normal mode solution displays a simple structure, composed of distinct sub-matrices which decouple the incident and scattered fields into $J$ families. The presence of a springs-mass substructure causes resonances which are shown to be related to the subsonic shell flexural waves, and an approximate analytic expression is derived for the quasi-flexural ...
Sindona, A; Pisarra, M; Maletta, S; Riccardi, P; Falcone, G
2010-12-01
Resonant neutralization of hyperthermal energy Na(+) ions impinging on Cu(100) surfaces is studied, focusing on two specific collision events: one in which the projectile is reflected off the surface, the other in which the incident atom penetrates the outer surface layers initiating a series of scattering processes, within the target, and coming out together with a single surface atom. A semi-empirical model potential is adopted that embeds: (i) the electronic structure of the sample, (ii) the central field of the projectile, and (iii) the contribution of the Cu atom ejected in multiple scattering events. The evolution of the ionization orbital of the scattered atom is simulated, backwards in time, using a wavepacket propagation algorithm. The output of the approach is the neutralization probability, obtained by projecting the time-reversed valence wavefunction of the projectile onto the initially filled conduction band states. The results are in agreement with available data from the literature (Keller et al 1995 Phys. Rev. Lett. 75 1654) indicating that the motion of surface atoms, exiting the targets with kinetic energies of the order of a few electronvolts, plays a significant role in the final charge state of projectiles.
Roshchupkin, S. P.
2009-08-01
The amplification factor of the electromagnetic field is theoretically studied for the scattering of nonrelativistic electrons by ions in the presence of the field of the elliptically polarized electromagnetic wave. A simple analytical formula for the gain is derived for the medium-intensity range. The formula supplements and extends the domain of applicability of the known Marcuse formula for the linear polarization in the presence of a weak field. It is demonstrated that the maximum gain is reached when the initial electron velocities belong to the polarization plane of the electromagnetic wave. In the range of optical frequencies, the amplification factor of the laser radiation can be significant for relatively high powers of electron beams.
Institute of Scientific and Technical Information of China (English)
冯立新; 李媛
2011-01-01
研究三层背景介质中的散射问题,首先将此问题转化为二维Helmholtz方程求解问题,然后给出一种基于PML技术和DSC算法的数值方法.得到该算法的部分误差估计,数值实验指出了算法的有效性.%The medium scattering problem in a three-layered background environment is studied.The problem is simplified first to a two-dimensional Helmhohz equation,then a method based on the PML technique and the DSC algorithm is presented for numerical solution of the problem.Certain errors of the method are given.The efficiency of the method is examined by numerical examples.
Zhang, Aiwu
2016-01-01
The geometric-mean method is often used to estimate the spatial resolution of a position-sensitive detector probed by tracks. It calculates the resolution solely from measured track data without using a detailed tracking simulation and without considering multiple Coulomb scattering effects. Two separate linear track fits are performed on the same data, one excluding and the other including the hit from the probed detector. The geometric mean of the widths of the corresponding exclusive and inclusive residual distributions for the probed detector is then taken as a measure of the intrinsic spatial resolution of the probed detector: $\\sigma=\\sqrt{\\sigma_{ex}\\cdot\\sigma_{in}}$. The validity of this method is examined for a range of resolutions with a stand-alone Geant4 Monte Carlo simulation that specifically takes multiple Coulomb scattering in the tracking detector materials into account. Using simulated as well as actual tracking data from a representative beam test scenario, we find that the geometric-mean ...
Institute of Scientific and Technical Information of China (English)
周宁; 王江安; 梁善勇; 吴荣华
2013-01-01
Multiple scattering effect about Ship wake bubble is important for optical wake detection.Aiming at the effect of multiple bubble scattering on backscattering light intensity and degree of polarization,the polarization state of the photon was tracked by Euler vector method.Under the incident conditions of linearly polarized light and circularly polarized light,the characteristics difference was analyzed,which the different echo signals produce in the backward scattering light intensity and the degree of polarization,and the feasibility that the Euler vector method is used to optical wake of detection field is verified.%舰船尾流气泡的多次散射效应对光尾流探测领域的研究具有重要意义.针对水中气泡多次散射对后向散射光强以及偏振度的影响规律问题,基于矢量Monte Carlo方法,采用欧拉矢量法对光子在水中气泡后向散射偏振态进行跟踪,对比分析了线偏振、圆偏振激光入射情况下,不同散射次数回波信号在强度和偏振度特性上的差异性,验证了欧拉矢量法用于光尾流探测仿真领域的可行性.
Indian Academy of Sciences (India)
Sujan Sengupta; Mark S Marley
2011-07-01
Chandrasekhar’s formalisms for the transfer of polarized radiation are used to explain the observed dust scattering polarization of brown dwarfs in the optical band. Model polarization profiles for hot and young directly imaged extrasolar planets are presented with specific prediction of the degree of polarization in the infrared. The model invokes Chandrasekhar’s formalism for the rotation-induced oblateness of the objects that gives rise to the necessary asymmetry for yielding net non-zero disk integrated linear polarization. The observed optical polarization constrains the surface gravity and could be a tool to estimate the mass of extrasolar planets.
Sica, R J; Haefele, A
2016-02-01
Lidar measurements of the atmospheric water vapor mixing ratio provide an excellent complement to radiosoundings and passive, ground-based remote sensors. Lidars are now routinely used that can make high spatial-temporal resolution measurements of water vapor from the surface to the stratosphere. Many of these systems can operate during the day and night, with operation only limited by clouds thick enough to significantly attenuate the laser beam. To enhance the value of these measurements for weather and climate studies, this paper presents an optimal estimation method (OEM) to retrieve the water vapor mixing ratio, aerosol optical depth profile, Ångstrom exponent, lidar constants, detector dead times, and measurement backgrounds from multichannel vibrational Raman-scatter lidars. The OEM retrieval provides the systematic uncertainties due to the overlap function, calibration factor, air density and Rayleigh-scatter cross sections, in addition to the random uncertainties of the retrieval due to measurement noise. The OEM also gives the vertical resolution of the retrieval as a function of height, as well as the height to which the contribution of the a priori is small. The OEM is applied to measurements made by the Meteoswiss Raman Lidar for Meteorological Observations (RALMO) in the day and night for clear and cloudy conditions. The retrieved water vapor mixing ratio is in excellent agreement with both the traditional lidar retrieval method and coincident radiosoundings.
Onset of color decoherence for soft gluon radiation in medium
Mehtar-Tani, Yacine; Tywoniuk, Konrad
2011-01-01
We report on recent studies of the phenomenon of color decoherence in jets in QCD media. The effect is most clearly observed in the radiation pattern of a quark-antiquark antenna, created in the same quantum state, traversing a dense color deconfined plasma. Multiple scattering with the medium color charges gradually destroys the coherence of the antenna. In the limit of opaque media this ultimately leads to independent radiation off the antenna constituents. Accordingly, radiation off the total charge vanishes implying a memory loss effect induced by the medium.
Wang, Xiao-Dong; Li, Yu-Lei; Luo, Wen; Wu, Hui-Yin; Yang, He-Run; Chen, Guo-Xiang; Zhu, Zhi-Chao; Zhao, Xiu-Liang
2016-01-01
Muon tomography is developing as a promising system to detect high-Z (atomic number) material for ensuring homeland security. In the present work, three kinds of spatial locations of materials which are made of aluminum, iron, lead and uranium are simulated with GEANT4 codes, which are horizontal, diagonal and vertical objects, respectively. Two statistical algorithms are used with MATLAB software to reconstruct the image of detected objects, which are the Point of Closet Approach (PoCA) and Maximum Likelihood Scattering-Expectation Maximization iterative algorithm (MLS-EM), respectively. Two analysis methods are used to evaluate the quality of reconstruction image, which are the Receiver Operating Characteristic (ROC) and the localization ROC (LROC) curves, respectively. The reconstructed results show that, compared with PoCA algorithm, MLS-EM can achieve a better image quality in both edge preserving and noise reduction. And according to the analysis of ROC (LROC) curves, it shows that MLS-EM algorithm can ...
Val'kov, V. V.; Aksenov, S. V.; Ulanov, E. A.
2015-02-01
We present a solution for the problem of quantum electron transport through a magnetic atom adsorbed inside a break junction with paramagnetic metal electrodes. In agreement with experimental data, it was assumed that the conduction electrons experience inelastic scattering by the adsorbate due to s-d(f)-exchange interaction. The Keldysh technique was employed to obtain a general expression describing a current through the multilevel structure at finite temperatures in terms of the nonequilibrium Green's function. The use of the atomic representation allowed to exactly account for the non-equidistant structure of the energy spectrum of a magnetic atom and to simplify substantially the application of the Wick theorem for construction of the nonequilibrium diagrammatic technique for the Hubbard operators. The calculation of the current-voltage characteristics of the magnetic adatom in the tunnel regime at low temperatures revealed the presence of regions with a negative differential conductance in a magnetic field.