Multiple scattering in the nuclear rearrangement reactions at medium energy
International Nuclear Information System (INIS)
Tekou, A.
1980-09-01
It is shown that the multiple scattering mechanism is very important in the transfer of the large momenta involved in the nuclear rearrangement reactions at medium energy. In contrast to the usual belief, the reaction cross-section is not very sensitive to the high momenta components of the nuclear wave function. The multiple scattering mechanism is especially important in 4 He(p,d) 3 He reaction around 800 MeV. Here the collisions involving two nucleons of the target nucleus are dominant. The triple collisions contribution is also important. The four collision contribution is negligible in the forward direction and sizeable at large angles. Thus, using the K.M.T. approach in DWBA calculations, the second order term of the optical potential must be included. So, is it not well established that the second term of the K.M.T. optical potential is important for the proton elastic scattering on light nuclei. (author)
Rakotonarivo , Sandrine; Walker , S.C.; Kuperman , W. A.; Roux , Philippe
2011-01-01
International audience; 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 interact...
Energy Technology Data Exchange (ETDEWEB)
Gorodnichev, E. E., E-mail: gorodn@theor.mephi.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation)
2016-12-15
For elliptically polarized light incident on a two-dimensional medium with large inhomogeneities, the Stokes parameters of scattered waves are calculated. Multiple scattering is assumed to be sharply anisotropic. The degree of polarization of scattered radiation is shown to be a nonmonotonic function of depth when the incident wave is circularly polarized or its polarization vector is not parallel to the symmetry axis of the inhomogeneities.
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. © 2011 Acoustical Society of America
Coherent transmission of an ultrasonic shock wave through a multiple scattering medium.
Viard, Nicolas; Giammarinaro, Bruno; Derode, Arnaud; Barrière, Christophe
2013-08-01
We report measurements of the transmitted coherent (ensemble-averaged) wave resulting from the interaction of an ultrasonic shock wave with a two-dimensional random medium. Despite multiple scattering, the coherent waveform clearly shows the steepening that is typical of nonlinear harmonic generation. This is taken advantage of to measure the elastic mean free path and group velocity over a broad frequency range (2-15 MHz) in only one experiment. Experimental results are found to be in good agreement with a linear theoretical model taking into account spatial correlations between scatterers. These results show that nonlinearity and multiple scattering are both present, yet uncoupled.
Jeong, Seungwon; Lee, Ye-Ryoung; Choi, Wonjun; Kang, Sungsam; Hong, Jin Hee; Park, Jin-Sung; Lim, Yong-Sik; Park, Hong-Gyu; Choi, Wonshik
2018-05-01
The efficient delivery of light energy is a prerequisite for the non-invasive imaging and stimulating of target objects embedded deep within a scattering medium. However, the injected waves experience random diffusion by multiple light scattering, and only a small fraction reaches the target object. Here, we present a method to counteract wave diffusion and to focus multiple-scattered waves at the deeply embedded target. To realize this, we experimentally inject light into the reflection eigenchannels of a specific flight time to preferably enhance the intensity of those multiple-scattered waves that have interacted with the target object. For targets that are too deep to be visible by optical imaging, we demonstrate a more than tenfold enhancement in light energy delivery in comparison with ordinary wave diffusion cases. This work will lay a foundation to enhance the working depth of imaging, sensing and light stimulation.
A multiple scattering theory for EM wave propagation in a dense random medium
Karam, M. A.; Fung, A. K.; Wong, K. W.
1985-01-01
For a dense medium of randomly distributed scatterers an integral formulation for the total coherent field has been developed. This formulation accounts for the multiple scattering of electromagnetic waves including both the twoand three-particle terms. It is shown that under the Markovian assumption the total coherent field and the effective field have the same effective wave number. As an illustration of this theory, the effective wave number and the extinction coefficient are derived in terms of the polarizability tensor and the pair distribution function for randomly distributed small spherical scatterers. It is found that the contribution of the three-particle term increases with the particle size, the volume fraction, the frequency and the permittivity of the particle. This increase is more significant with frequency and particle size than with other parameters.
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.
Energy Technology Data Exchange (ETDEWEB)
Berginc, G [THALES, 2 avenue Gay-Lussac 78995 ELANCOURT (France)
2013-11-30
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. (coherent light scattering)
Light focusing through a multiple scattering medium: ab initio computer simulation
Danko, Oleksandr; Danko, Volodymyr; Kovalenko, Andrey
2018-01-01
The present study considers ab initio computer simulation of the light focusing through a complex scattering medium. The focusing is performed by shaping the incident light beam in order to obtain a small focused spot on the opposite side of the scattering layer. MSTM software (Auburn University) is used to simulate the propagation of an arbitrary monochromatic Gaussian beam and obtain 2D distribution of the optical field in the selected plane of the investigated volume. Based on the set of incident and scattered fields, the pair of right and left eigen bases and corresponding singular values were calculated. The pair of right and left eigen modes together with the corresponding singular value constitute the transmittance eigen channel of the disordered media. Thus, the scattering process is described in three steps: 1) initial field decomposition in the right eigen basis; 2) scaling of decomposition coefficients for the corresponding singular values; 3) assembling of the scattered field as the composition of the weighted left eigen modes. Basis fields are represented as a linear combination of the original Gaussian beams and scattered fields. It was demonstrated that 60 independent control channels provide focusing the light into a spot with the minimal radius of approximately 0.4 μm at half maximum. The intensity enhancement in the focal plane was equal to 68 that coincided with theoretical prediction.
Quantum Optical Multiple Scattering
DEFF Research Database (Denmark)
Ott, Johan Raunkjær
. In the first part we use a scattering-matrix formalism combined with results from random-matrix theory to investigate the interference of quantum optical states on a multiple scattering medium. We investigate a single realization of a scattering medium thereby showing that it is possible to create entangled...... states by interference of squeezed beams. Mixing photon states on the single realization also shows that quantum interference naturally arises by interfering quantum states. We further investigate the ensemble averaged transmission properties of the quantized light and see that the induced quantum...... 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...
Energy Technology Data Exchange (ETDEWEB)
Blazhevich, S. V.; Kos’kova, T. V.; Noskov, A. V., E-mail: noskovbupk@mail.ru [Belgorod State National Research University (Russian Federation)
2016-01-15
A dynamic theory of coherent X-ray radiation generated in a periodic layered medium by a relativistic electron multiply scattered by target atoms has been developed. The expressions describing the spectral–angular characteristics of parametric X-ray radiation and diffracted transition radiation are derived. Numerical calculations based on the derived expressions have been performed.
Medium energy ion scattering (MEIS)
International Nuclear Information System (INIS)
Dittmann, K.; Markwitz, A.
2009-01-01
This report gives an overview about the technique and experimental study of medium energy ion scattering (MEIS) as a quantitative technique to determine and analyse the composition and geometrical structure of crystalline surfaces and near surface-layers by measuring the energy and yield of the backscattered ions. The use of a lower energy range of 50 to 500 keV accelerated ions impinging onto the target surface and the application of a high-resolution electrostatic energy analyser (ESA) makes medium energy ion scattering spectroscopy into a high depth resolution and surface-sensitive version of RBS with less resulting damage effects. This report details the first steps of research in that field of measurement technology using medium energetic backscattered ions detected by means of a semiconductor radiation detector instead of an ESA. The study of medium energy ion scattering (MEIS) has been performed using the 40 keV industrial ion implanter established at GNS Sciences remodelled with supplementary high voltage insulation for the ion source in order to apply voltages up to 45 kV, extra apertures installed in the beamline and sample chamber in order to set the beam diameter accurately, and a semiconductor radiation detector. For measurement purposes a beam of positive charged helium ions accelerated to an energy of about 80 keV has been used impinging onto target surfaces of lead implanted into silicon (PbSi), scandium implanted into aluminium (ScAl), aluminium foil (Al) and glassy carbon (C). First results show that it is possible to use the upgraded industrial implanter for medium energy ion scattering. The beam of 4 He 2+ with an energy up to 88 keV has been focussed to 1 mm in diameter. The 5 nA ion beam hit the samples under 2 x 10 -8 mbar. The results using the surface barrier detector show scattering events from the samples. Cooling of the detector to liquid nitrogen temperatures reduced the electronic noise in the backscattering spectrum close to zero. A
Scattering and multiple scattering in disordered materials
International Nuclear Information System (INIS)
Weaver, R.L.; Butler, W.H.
1992-01-01
The papers in this section were presented at a joint session of symposium V on Applications of Multiple Scattering Theory and of Symposium P on Disordered Systems. They show that the ideas of scattering theory can help us to understand a very broad class of phenomena
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.
Phase object retrieval through scattering medium
Zhao, Ming; Zhao, Meijing; Wu, Houde; Xu, Wenhai
2018-05-01
Optical imaging through a scattering medium has been an interesting and important research topic, especially in the field of biomedical imaging. However, it is still a challenging task due to strong scattering. This paper proposes to recover the phase object behind the scattering medium from one single-shot speckle intensity image using calibrated transmission matrices (TMs). We construct the forward model as a non-linear mapping, since the intensity image loses the phase information, and then a generalized phase retrieval algorithm is employed to recover the hidden object. Moreover, we show that a phase object can be reconstructed with a small portion of the speckle image captured by the camera. The simulation is performed to demonstrate our scheme and test its performance. Finally, a real experiment is set up, we measure the TMs from the scattering medium, and then use it to reconstruct the hidden object. We show that a phase object of size 32 × 32 is retrieved from 150 × 150 speckle grains, which is only 1/50 of the speckles area. We believe our proposed method can benefit the community of imaging through the scattering medium.
Medium energy hadron scattering from nuclei
International Nuclear Information System (INIS)
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 γ unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from 154 Sm and 154 Gd. 27 refs., 5 figs., 1 tab
A direct sampling method for inverse electromagnetic medium scattering
Ito, Kazufumi; Jin, Bangti; Zou, Jun
2013-01-01
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
Multiple scattering processes: inverse and direct
International Nuclear Information System (INIS)
Kagiwada, H.H.; Kalaba, R.; Ueno, S.
1975-01-01
The purpose of the work is to formulate inverse problems in radiative transfer, to introduce the functions b and h as parameters of internal intensity in homogeneous slabs, and to derive initial value problems to replace the more traditional boundary value problems and integral equations of multiple scattering with high computational efficiency. The discussion covers multiple scattering processes in a one-dimensional medium; isotropic scattering in homogeneous slabs illuminated by parallel rays of radiation; the theory of functions b and h in homogeneous slabs illuminated by isotropic sources of radiation either at the top or at the bottom; inverse and direct problems of multiple scattering in slabs including internal sources; multiple scattering in inhomogeneous media, with particular reference to inverse problems for estimation of layers and total thickness of inhomogeneous slabs and to multiple scattering problems with Lambert's law and specular reflectors underlying slabs; and anisotropic scattering with reduction of the number of relevant arguments through axially symmetric fields and expansion in Legendre functions. Gaussian quadrature data for a seven point formula, a FORTRAN program for computing the functions b and h, and tables of these functions supplement the text
Laser light scattering in Brownian medium
International Nuclear Information System (INIS)
Suwono; Santoso, Budi; Baiquni, A.
1983-01-01
The principle of laser light scattering in Brownian medium and photon correlation spectroscopy are described in detail. Their application to the study of the behaviour of a polystyrene latex solution are discussed. The auto-correlation function of light scattered by the polystyrene latex solution in various angle, various temperature and in various sample times, have been measured. Information on the translation diffusion coefficient and size on the particle can be obtained from the auto-correlation function. Good agreement between the available data and experiment is shown. (author)
Determination of multiple scattering effects
International Nuclear Information System (INIS)
Langevin, M.
1981-01-01
The integration of Sigmund and Winterbon numerical values is extended to the reduced thickness tau=2000. The diagram obtained allows a simple determination of the multiple scattering effect for different targets and projectiles [fr
A two-stage method for inverse medium scattering
Ito, Kazufumi; Jin, Bangti; Zou, Jun
2013-01-01
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
Quantum optics in multiple scattering random media
DEFF Research Database (Denmark)
Lodahl, Peter; Lagendijk, Ad
2005-01-01
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......-tions that should be readily attainable experimentally is devised. Figure 1. Inverse total transmission of shot noise (left) and technical noise (right) as a function of the thickness of the ran-dom medium. The experimental data are well explained by theory (curves). [1] J. Tworzydlo and C.W.J. Beenakker, Phys. Rev...
Significance of multiple scattering in imaging through turbid media
International Nuclear Information System (INIS)
Zardecki, A.; Gerstl, S.A.W.
1986-01-01
The degradation of image quality in a turbid medium is analyzed within the framework of the small-angle approximation, the diffusion approximation, and a rigorous two-dimensional radiative transfer equation. These three approaches allow us to emphasize different aspects of the imaging problem when multiple scattering effects are important. For a medium with a forward-peaked phase function, the separation of multiple scattering into a series of scatterings of various order provides a fruitful technique. The use of the diffusion approximation and transport theory extends the determination of the modulation transfer function to a turbid medium with an arbitrary degree of anisotropy
Effect of multiple scattering on lidar measurements
International Nuclear Information System (INIS)
Cohen, A.
1977-01-01
The lidar equation in its standard form involves the assumption that the scattered irradiance reaching the lidar receiver has been only singly scattered. However, in the cases of scattering from clouds and thick aerosol layers, it is shown that multiple scattering cannot be neglected. An experimental method for the detection of multiple scattering by depolarization measurement techniques is discussed. One method of theoretical calculations of double-scattering is presented and discussed
A direct sampling method to an inverse medium scattering problem
Ito, Kazufumi; Jin, Bangti; Zou, Jun
2012-01-01
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
Biophotonic applications of eigenchannels in a scattering medium (Conference Presentation)
Kim, Moonseok; Choi, Wonjun; Choi, Youngwoon; Yoon, Changhyeong; Choi, Wonshik
2016-03-01
When waves travel through disordered media such as ground glass and skin tissues, they are scattered multiple times. Most of the incoming energy bounces back at the superficial layers and only a small fraction can penetrate deep inside. This has been a limiting factor for the working depth of various optical techniques. We present a systematic method to enhance wave penetration to the scattering media. Specifically, we measured the reflection matrix of a disordered medium with wide angular coverage for each orthogonal polarization states. From the reflection matrix, we identified reflection eigenchannels of the medium, and shaped the incident wave into the reflection eigenchannel with smallest eigenvalue, which we call anti-reflection mode. This makes reflectance reduced and wave penetration increased as a result of the energy conservation. We demonstrated transmission enhancement by more than a factor of 3 by the coupling of the incident waves to the anti-reflection modes. Based on the uneven distribution of eigenvalues of reflection eigenchannels, we further developed an iterative feedback control method for finding and coupling light to anti-reflection modes. Since this adaptive control method can keep up with sample perturbation, it promotes the applicability of exploiting reflection eigenchannels. Our approach of delivering light deep into the scattering media will contribute to enhancing the sensitivity of detecting objects hidden under scattering layers, which is universal problem ranging from geology to life science.
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.
Gamma holography from multiple scattering
International Nuclear Information System (INIS)
Coussement, R.
2007-01-01
Since the introduction of heterodyne methods for synchrotron radiation (Cousesement et al. in Phys. Rev. B 54:16003, 1996; Callens et al. in Phys. Rev. 67:104423, 2003) one observes interferences between two scattering amplitudes; the scattering amplitude of resonant nuclei in a reference sample and the scattering amplitude of nuclei in the sample under investigation. Theses interferences can easily been observed as resonances in velocity spectra when one uses a time integrated method. They can also been observed as quantum beats, when one would use the time differential method. For both methods it is important that one uses a reference sample and therefore both methods disserved the name 'heterodyne methods.' As theses interferences are a product of two scattering amplitudes, the amplitude of a wave scattered form the investigated sample can be known with its phase. But it is assumed that the reference wave is known in advance by a proper choice of the reference sample. At first sight it is very likely that multiple scattering would add more complexity but in this paper it is claimed that on the contrary it provide a bonus, especially for single crystals. It provokes only a line broadening and a line shift of the resonances in the velocity spectra (or a change in the damping and frequency of the quantum beats when the time spectra are registered). Moreover these changes in the line shapes can easily be measured and they provide all the information needed to reconstruct a 3-D picture of the atomic arrangement of resonant nuclei and moreover they distinguish between different hyperfine sites. The method may be more practical for measurements on synchrotron radiation but it does also apply to velocity spectra obtained from resonant scattering with strong sources. The use of radioactive sources suffer from the disadvantage of poorer statistics or much longer accumulation times but they enjoy the advantage to be table-top and at-home experiments. As strong sources are
Jet multiplicity distributions: medium dependence in MLLA
International Nuclear Information System (INIS)
Armesto, Nestor; Pajares, Carlos; Quiroga-Arias, Paloma
2009-01-01
We study the medium dependence of the multiplicity distributions in the modified leading logarithmic approximation. We focus in the enhancement in the number of branchings as the partons travel trough a dense medium created in a heavy-ion collision. We study the effect of a higher number of splittings in some jet observables by introducing the medium as a constant (f med ) in the splitting functions. Having as our ansatz for the quark and gluon jets mean multiplicities left angle n G right angle =e γy and left angle n Q right angle =r -1 e γy , we study in an analytic approach the dependence with the medium (f med ) of the anomalous dimension (γ), the multiplicity ratio (r), and so the mean multiplicities. We also obtain the higher-order moments of the multiplicity distribution, what allows us to study its dispersion. (orig.)
Thermal-neutron multiple scattering: critical double scattering
International Nuclear Information System (INIS)
Holm, W.A.
1976-01-01
A quantum mechanical formulation for multiple scattering of thermal-neutrons from macroscopic targets is presented and applied to single and double scattering. Critical nuclear scattering from liquids and critical magnetic scattering from ferromagnets are treated in detail in the quasielastic approximation for target systems slightly above their critical points. Numerical estimates are made of the double scattering contribution to the critical magnetic cross section using relevant parameters from actual experiments performed on various ferromagnets. The effect is to alter the usual Lorentzian line shape dependence on neutron wave vector transfer. Comparison with corresponding deviations in line shape resulting from the use of Fisher's modified form of the Ornstein-Zernike spin correlations within the framework of single scattering theory leads to values for the critical exponent eta of the modified correlations which reproduce the effect of double scattering. In addition, it is shown that by restricting the range of applicability of the multiple scattering theory from the outset to critical scattering, Glauber's high energy approximation can be used to provide a much simpler and more powerful description of multiple scattering effects. When sufficiently close to the critical point, it provides a closed form expression for the differential cross section which includes all orders of scattering and has the same form as the single scattering cross section with a modified exponent for the wave vector transfer
Effects of multiple scattering and target structure on photon emission
International Nuclear Information System (INIS)
Blankenbecler, R.
1996-05-01
The Landau-Pomeranchuk-Migdal effect is the suppression of Bethe-Heitler radiation caused by multiple scattering in the target medium. The quantum treatment given by S.D. Drell and the author for homogeneous targets of finite thickness will be reviewed. It will then be extended to structured targets. In brief, it is shown that radiators composed of separated plates or of a medium with a spatially varying radiation length can exhibit unexpected structure, even coherence maxima and minima, in their photon spectra. Finally, a functional integral method for performing the averaging implicit in multiple scattering will be briefly discussed and the leading corrections to previous results evaluated
Depth distribution of multiple order X-ray scatter
International Nuclear Information System (INIS)
Yao Weiguang; Leszczynski, Konrad
2008-01-01
Scatter can significantly affect quality of projectional X-ray radiographs and tomographic reconstructions. With this in mind, we examined some of the physical properties of multiple orders of scatter of X-ray photons traversing through a layer of scattering media such as water. Using Monte Carlo techniques, we investigated depth distributions of interactions between incident X-ray photons and water before the resulting scattered photons reach the detector plane. Effects of factors such as radiation field size, air gap, thickness of the layer of scattering medium and X-ray energy, on the scatter were included in the scope of this study. The following scatter characteristics were observed: (1) for a layer of scattering material corresponding to the typical subject thickness in medical imaging, frequency distribution of locations of the last scattering interaction increases approximately exponentially with depth, and the higher the order of scatter or the energy of the incident photon, the narrower is the distribution; (2) for the second order scatter, the distribution of locations of the first interaction is more uniform than that of the last interaction and is dependent on the energy of the primary photons. Theoretical proofs for some of these properties are given. These properties are important to better understanding of effects of scatter on the radiographic and tomographic imaging process and to developing effective methods for scatter correction
Multiple scattering theory of radiative transfer in inhomogeneous atmospheres.
Kanal, M.
1973-01-01
In this paper we treat the multiple scattering theory of radiative transfer in plane-parallel inhomogeneous atmospheres. The treatment presented here may be adopted to model atmospheres characterized by an optical depth dependent coherent scattering phase function. For the purpose of illustration we consider the semi-infinite medium in which the absorption property of the atmosphere is characterized by an exponential function. The methodology employed here is the extension of the case treated previously by the author for homogeneous atmospheres.
Inelastic proton scattering at medium energy
International Nuclear Information System (INIS)
Love, W.G.
1980-01-01
Some of the most essential characteristics of the nucleon-nucleon interaction for probing nuclear structure at bombarding energies between 100 and 800 MeV are considered. With a local representation of the on-shell N-N t-matrix, data for a variety of specific transitions at IUCF and LAMPF energies are discussed with an emphasis on the nuclear structure information sampled by proton scattering. The importance of incorporating constraints on nuclear structure imposed by electron scattering is stressed. Some rather unique aspects of the (p,n) reaction at intermediate energies are discussed in terms of its energy dependence and nuclear structure sum rules. 11 figures
Statistical properties of laser light scattering in Brownian medium
International Nuclear Information System (INIS)
Suwono; Santoso, Budi; Baiquni, A.
1983-01-01
Relationship between statistical properties of laser light scattering in Brownian medium and photon-counting distributions are described in detail. A coherence optical detection has been constructed and by using photon-counting technique the ensemble distribution of the scattered field within space and time coherence has been measured. Good agreement between theory and experiment is shown. (author)
Jet multiplicity distributions: medium dependence in MLLA
Energy Technology Data Exchange (ETDEWEB)
Armesto, Nestor; Pajares, Carlos; Quiroga-Arias, Paloma [Universidade de Santiago de Compostela, Departamento de Fisica de Particulas and IGFAE, Santiago de Compostela (Spain)
2009-07-15
We study the medium dependence of the multiplicity distributions in the modified leading logarithmic approximation. We focus in the enhancement in the number of branchings as the partons travel trough a dense medium created in a heavy-ion collision. We study the effect of a higher number of splittings in some jet observables by introducing the medium as a constant (f{sub med}) in the splitting functions. Having as our ansatz for the quark and gluon jets mean multiplicities left angle n{sub G} right angle =e{sup {gamma}}{sup y} and left angle n{sub Q} right angle =r{sup -1}e{sup {gamma}}{sup y}, we study in an analytic approach the dependence with the medium (f{sub med}) of the anomalous dimension ({gamma}), the multiplicity ratio (r), and so the mean multiplicities. We also obtain the higher-order moments of the multiplicity distribution, what allows us to study its dispersion. (orig.)
Medium dependence of multiplicity distributions in MLLA
Energy Technology Data Exchange (ETDEWEB)
Armesto, Nestor; Pajares, Carlos; Quiroga-Arias, Paloma [Universidade de Santiago de Compostela, Departamento de Fisica de Particulas and IGFAE, Santiago de Compostela (Spain)
2009-06-15
We study the modification of the multiplicity distributions in MLLA due to the presence of a QCD medium. The medium is introduced through a multiplicative constant (f{sub med}) in the soft infrared parts of the kernels of the QCD evolution equations. Using the asymptotic ansatz for mean multiplicities of the quark and gluons, left angle n{sub G} right angle =e{sup {gamma}}{sup y} and left angle n{sub Q} right angle =r {sup -1}e{sup {gamma}}{sup y}, respectively, we study two cases: fixed {gamma} as previously considered in the literature, and fixed {alpha}{sub s}. We find opposite behaviors of the dispersion of the multiplicity distributions with increasing f{sub med} in both cases. For fixed {gamma} the dispersion decreases, while for fixed {alpha}{sub s} it increases. (orig.)
Medium dependence of multiplicity distributions in MLLA
International Nuclear Information System (INIS)
Armesto, Nestor; Pajares, Carlos; Quiroga-Arias, Paloma
2009-01-01
We study the modification of the multiplicity distributions in MLLA due to the presence of a QCD medium. The medium is introduced through a multiplicative constant (f med ) in the soft infrared parts of the kernels of the QCD evolution equations. Using the asymptotic ansatz for mean multiplicities of the quark and gluons, left angle n G right angle =e γy and left angle n Q right angle =r -1 e γy , respectively, we study two cases: fixed γ as previously considered in the literature, and fixed α s . We find opposite behaviors of the dispersion of the multiplicity distributions with increasing f med in both cases. For fixed γ the dispersion decreases, while for fixed α s it increases. (orig.)
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.
Removal of divergences in the problem of scattering of a particle beam by a medium
International Nuclear Information System (INIS)
Kuz'min, V.L.
1977-01-01
Scattering of a beam of particles (neutrons) by a medium is considered. After the averaging according to the statistical mechanics rules, the cross-section of the process is represented in the form of the series including many-particle distribution functions. The series describes the scattering processes of arbitrary multiplicity. Disconnected parts of the distribution functions give rise to divergences. A method of the re-summation of the original series is proposed, which removes all the divergences completely
Scattering theory and effective medium approximations to heterogeneous materials
International Nuclear Information System (INIS)
Gubernatis, J.E.
1977-01-01
The formal analogy existing between problems studied in the microscopic theory of disordered alloys and problems concerned with the effective (macroscopic) behavior of heterogeneous materials is discussed. Attention is focused on (1) analogous approximations (effective medium approximations) developed for the microscopic problems by scattering theory concepts and techniques, but for the macroscopic problems principally by intuitive means, (2) the link, provided by scattering theory, of the intuitively developed approximations to a well-defined perturbative analysis, (3) the possible presence of conditionally convergent integrals in effective medium approximations
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.
Lensless ghost imaging through the strongly scattering medium
International Nuclear Information System (INIS)
Yang Zhe; Zhao Xueliang; Li Junlin; Zhao Lianjie; Qin Wei
2016-01-01
Lensless ghost imaging has attracted much interest in recent years due to its profound physics and potential applications. In this paper we report studies of the robust properties of the lensless ghost imaging system with a pseudo-thermal light source in a strongly scattering medium. The effects of the positions of the strong medium on the ghost imaging are investigated. In the lensless ghost imaging system, a pseudo-thermal light is split into two correlated beams by a beam splitter. One beam goes to a charge-coupled detector camera, labeled as CCD2. The other beam goes to an object and then is collected in another charge-coupled detector camera, labeled as CCD1, which serves as a bucket detector. When the strong medium, a pane of ground glass disk, is placed between the object and CCD1, the bucket detector, the quality of ghost imaging is barely affected and a good image could still be obtained. The quality of the ghost imaging can also be maintained, even when the ground glass is rotating, which is the strongest scattering medium so far. However, when the strongly scattering medium is present in the optical path from the light source to CCD2 or the object, the lensless ghost imaging system hardly retrieves the image of the object. A theoretical analysis in terms of the second-order correlation function is also provided. (paper)
Multiple scattering of ions in polyatomic materials
International Nuclear Information System (INIS)
Eastham, D.A.
1980-01-01
The equations which determine small angle multiple scattering in the thin polyatomic layers are evaluated numerically for certain cases. A simple approximate method for calculating the scattering in terms of an average target charge which is a function of the target thickness is given and compared with the exact numerical value. The results agree to better than 5% over a wide range of target composition and thickness. (orig.)
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...... fluctuations of the total transmission or reflection. In contrast, no pronounced spatial quantum correlations appear in the quadrature amplitudes where excess noise above the shot noise level is found....
Temporal reflectance from a light pulse irradiated medium embedded with highly scattering cores
International Nuclear Information System (INIS)
Hsu Peifeng; Lu Xiaodong
2007-01-01
This paper presents a new approach to utilize ultrashort pulsed laser for optical diagnostics with numerical simulations. The method is based on the use of ultrafast pulses with a pulsewidth selected according to the probed medium's radiative property and/or size. Our previous work in nonhomogeneous media has shown that the resulting time-resolved reflectance signal will have a unique characteristic: it will show a direct correlation of ballistic photon travel time and interface location, which is in between different layers or nonhomogeneous regions. The premise is based on utilizing the medium's structural information carried by the ballistic and snake photons without being masked by the diffuse photons. In this study, the space-time correlation is further explored in the case of minimally scattered photons from a large scattering coefficient core region embedded within a less-scattering medium. Time-resolved reflectance signals of the single scattering core and multiple scattering cores within a three-dimensional medium demonstrate the concept and illustrate the additional effect due to the scattered photons from the core region. A unique temporal signal profile's correlation at various detector positions with respect to the scattering core is explained in detail. The result has important implications. This approach will lead to a much simpler and more precise determination of the probed medium's composition or structure. Due to the large computational requirement to obtain the physical details of the light pulse propagation inside highly scattering multi-dimensional media, the reverse Monte-Carlo method is used. The potential applications of the method include non-destructive diagnostics, optical imaging, and remote sensing of underwater objects
Theoretical interpretation of medium energy nucleon nucleus inelastic scattering
International Nuclear Information System (INIS)
Lagrange, Christian
1970-06-01
A theoretical study is made of the medium energy nucleon-nucleus inelastic scattering (direct interaction), by applying the distorted wave Born approximation such as can be deduced from the paired equation method. It is applied to the interpretation of the inelastic scattering of 12 MeV protons by 63 Cu; this leads us to make use of different sets of wave functions to describe the various states of the target nucleus. We analyze the nature of these states and the shape of the nucleon-nucleus interaction potential, and we compare the results with those obtained from other theoretical and experimental work. (author) [fr
The inelastic scattering of medium energy α particles
International Nuclear Information System (INIS)
Crut, M.
1960-01-01
The aim of this work is to find out what are the properties of the so-called 'anomalous states' in medium weight nuclei. These states preferentially excited in the inelastic scattering of medium energy charged particles have an excitation energy at about 4 MeV for nuclei with Z ≤ 29 and in the range 2-3 MeV for high Z nuclei. From a combination of angular distribution data in the elastic and inelastic scattering of 30 MeV α particles, and correlation data between inelastic α particles and deexcitation γ rays, we show that for even-even nuclei, we can attribute spin 3 and parity minus to these 'anomalous states'. This is quite in agreement with the interpretation of these levels suggested by Lane as due to collective octupole oscillations. We give a resume of the theories used in the analysis of the data and a description of the experimental set-up. (author) [fr
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
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......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...... the full quantum model of multiple scattering....
Multiple-scattering corrections to the Beer-Lambert law
International Nuclear Information System (INIS)
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
Signature for g bosons from medium energy proton scattering experiments
International Nuclear Information System (INIS)
Kuyucak, S.
1993-01-01
We apply the recently developed algebraic (1/N expansion) scattering formalism to medium energy proton scattering from 154 Sm and 176 Yb. The nuclear structure effects in this formalism are described by the interacting boson model generalized to arbitrary interactions and types of bosons i.e. s,d,g, etc. We find that, in the sd boson model, a consistent description of cross sections is possible only for the 0 + and 2 + states. The failure of the model with regard to the 4 + states indicates that the effective hexadecapole operator used in the sd model is inadequate. In contrast, the data for scattering to the 0 + , 2 + and 4 + states could be consistently described in the sdg boson model. The spectroscopic data for the low-lying levels usually can not distinguish between the sd and sdg models due to renormalization of parameters, and one has to look at high spin or energy data for evidence of g bosons. The inelastic proton scattering experiments, on the other hand, directly probe the wave functions, and hence could provide a signature for g bosons even in the ground band states
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.
Positronium-alkali atom scattering at medium energies
International Nuclear Information System (INIS)
Chakraborty, Ajoy; Basu, Arindam; Sarkar, Nirmal K; Sinha, Prabal K
2004-01-01
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
Lateral displacement in small angle multiple scattering
Energy Technology Data Exchange (ETDEWEB)
Bichsel, H.; Hanson, K.M.; Schillaci, K.M. (Los Alamos National Lab., NM (USA))
1982-07-01
Values have been calculated for the average lateral displacement in small angle multiple scattering of protons with energies of several hundred MeV. The calculations incorporate the Moliere distribution which does not make the gaussian approximations of the distribution in projected angle and lateral deflections. Compared to other published data, such approximations can lead to errors in the lateral displacement of up to 10% in water.
Multiple Scattering Model for Optical Coherence Tomography with Rytov Approximation
Li, Muxingzi
2017-01-01
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
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 two...... output modes. It is shown that quantum interference survives averaging over all ensembles of disorder and manifests itself as increased photon correlations due to photon antibunching. Furthermore, the existence of continuous variable entanglement correlations in a volume speckle pattern is predicted. Our...
Anomalous resonance-radiation energy-transfer rate in a scattering dispersive medium
International Nuclear Information System (INIS)
Shekhtman, V.L.
1992-01-01
This paper describes a generalization of the concept of group velocity as an energy-transfer rate in a dispersive medium with complex refractive index when the polaritons, which are energy carriers, undergo scattering, in contrast to the classical concept of the group velocity of free polaritons (i.e., without scattering in the medium). The concept of delay time from quantum multichannel-scattering, theory is used as the fundamental concept. Based on Maxwell's equations and the new mathematical Φ-function method, a consistent conceptual definition of group velocity in terms of the ratio of the coherent-energy flux density to the coherent-energy density is obtained for the first time, and a critical analysis of the earlier (Brillouin) understanding of energy-transfer rate is given in the light of radiation-trapping theory and the quantum theory of resonance scattering. The role of generalized group velocity is examined for the interpretation of the phenomenon of multiple resonance scattering, or radiation diffusion. The question of causality for the given problem is touched upon; a new relationship is obtained, called the microcausality condition, which limits the anomalous values of group velocity by way of the indeterminacy principle and the relativistic causality principle for macroscopic time intervals directly measurable in experiment, whereby attention is focused on the connection of the given microcausality condition and the well-known Wigner inequality for the time delay of spherical waves. 22 refs
Multiple-scattering in radar systems: A review
International Nuclear Information System (INIS)
Battaglia, Alessandro; Tanelli, Simone; Kobayashi, Satoru; Zrnic, Dusan; Hogan, Robin J.; Simmer, Clemens
2010-01-01
Although extensively studied within the lidar community, the multiple scattering phenomenon has always been considered a rare curiosity by radar meteorologists. Up to few years ago its appearance has only been associated with two- or three-body-scattering features (e.g. hail flares and mirror images) involving highly reflective surfaces. Recent atmospheric research aimed at better understanding of the water cycle and the role played by clouds and precipitation in affecting the Earth's climate has driven the deployment of high frequency radars in space. Examples are the TRMM 13.5 GHz, the CloudSat 94 GHz, the upcoming EarthCARE 94 GHz, and the GPM dual 13-35 GHz radars. These systems are able to detect the vertical distribution of hydrometeors and thus provide crucial feedbacks for radiation and climate studies. The shift towards higher frequencies increases the sensitivity to hydrometeors, improves the spatial resolution and reduces the size and weight of the radar systems. On the other hand, higher frequency radars are affected by stronger extinction, especially in the presence of large precipitating particles (e.g. raindrops or hail particles), which may eventually drive the signal below the minimum detection threshold. In such circumstances the interpretation of the radar equation via the single scattering approximation may be problematic. Errors will be large when the radiation emitted from the radar after interacting more than once with the medium still contributes substantially to the received power. This is the case if the transport mean-free-path becomes comparable with the instrument footprint (determined by the antenna beam-width and the platform altitude). This situation resembles to what has already been experienced in lidar observations, but with a predominance of wide- versus small-angle scattering events. At millimeter wavelengths, hydrometeors diffuse radiation rather isotropically compared to the visible or near infrared region where scattering is
Multiple scattering theory for space filling potentials
International Nuclear Information System (INIS)
Butler, W.H.; Brown, R.G.; Nesbet, R.K.
1990-01-01
Multiple scattering theory (MST) provides an efficient technique for solving the wave equation for the special case of muffin-tin potentials. Here MST is extended to treat space filling non-muffin tin potentials and its validity, accuracy and efficiency are tested by application of the two dimensional empty lattice test. For this test it is found that the traditional formulation of MST does not coverage as the number of partial waves is increased. A simple modification of MST, however, allows this problem to be solved exactly and efficiently. 15 refs., 3 tabs
International Nuclear Information System (INIS)
Tereshchenko, Sergei A; Podgaetskii, Vitalii M; Vorob'ev, Nikolai S; Smirnov, A V
1998-01-01
The conditions are identified for simultaneous observation of the peaks of scattered and unscattered (ballistic) photons in a narrow pulsed laser beam crossing a strongly scattering medium. The experimental results are explained on the basis of a nonstationary two-flux model of radiation transport. An analytic expression is given for the contribution of ballistic photons to the transmitted radiation, as a function of the characteristics of the scattering medium. It is shown that the ballistic photon contribution can be increased by the use of high-contrast substances which alter selectively the absorption and scattering coefficients of the medium. (laser applications and other topics in quantum electronics)
Coulomb interaction in multiple scattering theory
International Nuclear Information System (INIS)
Ray, L.; Hoffmann, G.W.; Thaler, R.M.
1980-01-01
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+ 208 Pb elastic scattering and compared with experimental data
Static and dynamic properties of multiple light scattering
Štěpánek, Petr
1993-11-01
We have examined the onset and evolution of multiple scattering of light on a series of latex dispersions as a function of increasing volume concentration φ of particles. We have shown that using vertically polarized incident light, the static scattered intensity becomes progressively depolarized, with increasing φ. The polarization of scattered light is completely random in the limit of strong multiple scattering. The spectra of decay times of dynamic light scattering display a region of oligo scattering at intermediate φ where both the single and multiple scattering components can be dynamically identified. For φ≳0.03 the limit of diffusive transport of light is attained. The obtained results confirm that our earlier measurements of dynamic light scattering on systems exhibiting critical opalescence are not influenced by multiple light scattering.
Refractive and diffractive scattering in the interstellar medium
International Nuclear Information System (INIS)
Cordes, J.M.; Pidwerbetsky, A.; Lovelace, R.V.E.
1986-01-01
Radio wave propagation through electron-density fluctuations in the ISM is studied. Observable propagation effects are explored using a one-dimensional thin-screen model for the turbulent medium. Diffraction caused by stochastic small-scale irregularities is combined with refraction from deterministic large-scale irregularities. Some of the effects are illustrated with numerical simulations of the wave propagation. Multiple imaging is considered, delineating the possible effects and discussing their extensions to two-dimensional screens and extended three-dimensional media. The case where refraction as well as diffraction is caused by a stochastic medium with a spectrum of a given form is considered. The magnitudes of observable effects is estimated for representative spectra that may be relevant to the ISM. The importance of the various effects for timing and scintillation observations of pulsars, VLBI observations of galactic and extragalactic radio sources, and for variability measurements of extragalactic sources is assessed. 47 references
Multiple scattering effects in 7Li
International Nuclear Information System (INIS)
Cox, A.J.; Warner, P.C.
1985-01-01
The differential cross-sections for the production of 0.478 MeV γ-rays following the inelastic scattering of 14 MeV neutrons in large samples of LiF, which will be used in fusion reactor blankets, have been measured. The neutrons were produced using the 3 H(d,n) 4 α reaction, with the deuterons being accelerated by a 150 kV SAMES type accelerator. In order to reduce the background level the γ-ray signal was gated, using a time of flight technique based on the α-particle associated with neutron production. Measurements of the γ-ray production differential cross-sections were made for various thicknesses of LiF. The results were compared to the predictions of the Monte Carlo Computer Code, MORSE, with an agreement of +-11% being achieved. In addition a phenomenological expression was found which is capable of predicting the variation in cross-sections with thickness due to multiple scattering effects to within +-12%. (author)
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.
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.)
Convergence of the multiple scattering expansion in XAFS and XANES
International Nuclear Information System (INIS)
Rehr, J.J.
1992-01-01
The convergence of the multiple-scattering expansion of XAFS and XANES by explicit path-bypath calculations. The approach is based on the fast scattering matrix formalism of Rehr and Albers, together with an automated path finder and filters that exclude negligible paths. High-order scattering terms are found to be essential, especially at low energies. Several factors including the magnitude of curved wave scattering amplitudes, inelastic losses and multiple-scattering Debye-Waller factors control convergence of the expansion. The convergence is illustrated explicitly for the case of diatomic molecules
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......Multiple acoustical signal interactions with sediment particles in the vicinity of the seabed may significantly change the course of sediment concentration profiles determined by inversion from acoustical backscattering measurements. The scattering properties of high concentrations of sediments...... is the question of proximity thresholds for influence of multiple scattering in terms of particle properties like volume fraction, average distance between particles or other related parameters. A few available experimental data indicate a significance of multiple scattering in suspensions where the concentration...
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...... theory and form a basis for future research on, e. g., quantum interference of multiple quantum states in a multiple scattering medium....
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.
Compton-scatter tissue densitometry: calculation of single and multiple scatter photon fluences
International Nuclear Information System (INIS)
Battista, J.J.; Bronskill, M.J.
1978-01-01
The accurate measurement of in vivo electron densities by the Compton-scatter method is limited by attenuations and multiple scattering in the patient. Using analytic and Monte Carlo calculation methods, the Clarke tissue density scanner has been modelled for incident monoenergetic photon energies from 300 to 2000 keV and for mean scattering angles of 30 to 130 degrees. For a single detector focussed to a central position in a uniform water phantom (25 x 25 x 25 cm 3 ) it has been demonstrated that: (1) Multiple scatter contamination is an inherent limitation of the Compton-scatter method of densitometry which can be minimised, but not eliminated, by improving the energy resolution of the scattered radiation detector. (2) The choice of the incident photon energy is a compromise between the permissible radiation dose to the patient and the tolerable level of multiple scatter contamination. For a mean scattering angle of 40 degrees, the intrinsic multiple-single scatter ratio decreases from 64 to 35%, and the radiation dose (per measurement) increases from 1.0 to 4.1 rad, as the incident photon energy increases from 300 to 2000 keV. These doses apply to a sampled volume of approximately 0.3 cm 3 and an electron density precision of 0.5%. (3) The forward scatter densitometer configuration is optimum, minimising both the dose and the multiple scatter contamination. For an incident photon energy of 1250 keV, the intrinsic multiple-single scatter ratio reduces from 122 to 27%, and the dose reduces from 14.3 to 1.2 rad, as the mean scattering angle decreases from 130 to 30 degrees. These calculations have been confirmed by experimental measurements. (author)
International Nuclear Information System (INIS)
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. - Highlights: • The Muller matrix of randomly distributed, densely packed spheres are investigated. • The effects of multiple scattering and dependent scattering are analyzed. • The accuracy of radiative transfer theory for densely packed spheres is discussed. • Dependent scattering correction takes effect at medium size parameter or smaller. • Performance of dependent scattering correction
Characterization of the Lung Parenchyma Using Ultrasound Multiple Scattering.
Mohanty, Kaustav; Blackwell, John; Egan, Thomas; Muller, Marie
2017-05-01
The purpose of the study described here was to showcase the application of ultrasound to quantitative characterization of the micro-architecture of the lung parenchyma to predict the extent of pulmonary edema. The lung parenchyma is a highly complex and diffusive medium for which ultrasound techniques have remained qualitative. The approach presented here is based on ultrasound multiple scattering and exploits the complexity of ultrasound propagation in the lung structure. The experimental setup consisted of a linear transducer array with an 8-MHz central frequency placed in contact with the lung surface. The diffusion constant D and transport mean free path L* of the lung parenchyma were estimated by separating the incoherent and coherent intensities in the near field and measuring the growth of the incoherent diffusive halo over time. Significant differences were observed between the L* values obtained in healthy and edematous rat lungs in vivo. In the control rat lung, L* was found to be 332 μm (±48.8 μm), whereas in the edematous lung, it was 1040 μm (±90 μm). The reproducibility of the measurements of L* and D was tested in vivo and in phantoms made of melamine sponge with varying air volume fractions. Two-dimensional finite difference time domain numerical simulations were carried out on rabbit lung histology images with varying degrees of lung collapse. Significant correlations were observed between air volume fraction and L* in simulation (r = -0.9542, p lung in which edema was simulated by adding phosphate-buffered saline revealed a linear relationship between the fluid volume fraction and L*. These results illustrate the potential of methods based on ultrasound multiple scattering for the quantitative characterization of the lung parenchyma. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.
Emittance of a finite scattering medium with refractive index greater than unity
International Nuclear Information System (INIS)
Crosbie, A.L.
1980-01-01
Refractive index and scattering can significantly influence the transfer of radiation in a semitransparent medium such as water, glass, plastics, or ceramics. In a recent article (1979), the author presented exact numerical results for the emittance of a semiinfinite scattering medium with a refractive index greater than unity. The present investigation extends the analysis to a finite medium. The physical situation consists of a finite planar layer. The isothermal layer emits, absorbs, and isotropically scatters thermal radiation. It is characterized by single scattering albedo, optical thickness, refractive index, and temperature. A formula for the directional emittance is derived, the directional emittance being the emittance of the medium multiplied by the interface transmittance. The ratio of hemispherical to normal emittance is tabulated and discussed
Acoustic scattering by multiple elliptical cylinders using collocation multipole method
International Nuclear Information System (INIS)
Lee, Wei-Ming
2012-01-01
This paper presents the collocation multipole method for the acoustic scattering induced by multiple elliptical cylinders subjected to an incident plane sound wave. To satisfy the Helmholtz equation in the elliptical coordinate system, the scattered acoustic field is formulated in terms of angular and radial Mathieu functions which also satisfy the radiation condition at infinity. The sound-soft or sound-hard boundary condition is satisfied by uniformly collocating points on the boundaries. For the sound-hard or Neumann conditions, the normal derivative of the acoustic pressure is determined by using the appropriate directional derivative without requiring the addition theorem of Mathieu functions. By truncating the multipole expansion, a finite linear algebraic system is derived and the scattered field can then be determined according to the given incident acoustic wave. Once the total field is calculated as the sum of the incident field and the scattered field, the near field acoustic pressure along the scatterers and the far field scattering pattern can be determined. For the acoustic scattering of one elliptical cylinder, the proposed results match well with the analytical solutions. The proposed scattered fields induced by two and three elliptical–cylindrical scatterers are critically compared with those provided by the boundary element method to validate the present method. Finally, the effects of the convexity of an elliptical scatterer, the separation between scatterers and the incident wave number and angle on the acoustic scattering are investigated.
Diffractive scattering on nuclei in multiple scattering theory with inelastic screening
International Nuclear Information System (INIS)
Zoller, V.R.
1988-01-01
The cross sections for the diffractive scattering of hadrons on nuclei are calculated in the two-channel approximation of multiple scattering theory. In contrast to the standard Glauber approach, it is not assumed that the nucleon scattering profile is a Gaussian or that the Regge radius of the hadron is small compared to the nuclear radius. The AGK Reggeon diagrammatic technique is used to calculate the topological cross sections and the cross sections for coherent and incoherent diffractive dissociation and quasielastic scattering. The features of hadron-nucleus scattering at superhigh energies are discussed
Secure data storage by three-dimensional absorbers in highly scattering volume medium
International Nuclear Information System (INIS)
Matoba, Osamu; Matsuki, Shinichiro; Nitta, Kouichi
2008-01-01
A novel data storage in a volume medium with highly scattering coefficient is proposed for data security application. Three-dimensional absorbers are used as data. These absorbers can not be measured by interferometer when the scattering in a volume medium is strong enough. We present a method to reconstruct three-dimensional absorbers and present numerical results to show the effectiveness of the proposed data storage.
Electromagnetic radiation of ultrarelativistic particles at scattering in excited medium
International Nuclear Information System (INIS)
Malyshevskij, V.S.
1990-01-01
The interaction between relativistic particles and a gaseous or condensed medium with a high density of nondegenerate excited quantum states involves the coherent conversion of atomic or molecular excitations into electromagnetic radiation
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
1997-12-31
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.
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.
Reproducibility of artificial multiple scattering media
Marakis, Evangelos; van Harten, Wouter; Uppu, Ravitej; Pinkse, Pepijn Willemszoon Harry
2016-01-01
State of the art authentication systems depend on physical unclonable functions (PUF) [1], physical keys that are assumed unclonable due to technological constraints. Random scattering media, dielectric materials with rapid and random refractive index variations, are considered as ideal optical PUFs
Certain theories of multiple scattering in random media of discrete scatterers
International Nuclear Information System (INIS)
Olsen, R.L.; Kharadly, M.M.Z.; Corr, D.G.
1976-01-01
New information is presented on the accuracy of the heuristic approximations in two important theories of multiple scattering in random media of discrete scatterers: Twersky's ''free-space'' and ''two-space scatterer'' formalisms. Two complementary approaches, based primarily on a one-dimensional model and the one-dimensional forms of the theories, are used. For scatterer distributions of low average density, the ''heuristic'' asymptotic forms for the coherent field and the incoherent intensity are compared with asymptotic forms derived from a systematic analysis of the multiple scattering processes. For distributions of higher density, both in the average number of scatterers per wavelength and in the degree of packing of finite-size scatterers, the analysis is carried out ''experimentally'' by means of a Monte Carlo computer simulation. Approximate series expressions based on the systematic approach are numerically evaluated along with the heuristic expressions. The comparison (for both forward- and back-scattered field moments) is made for the worst-case conditions of strong multiple scattering for which the theories have not previously been evaluated. Several significant conclusions are drawn which have certain practical implications: in application of the theories to describe some of the scattering phenomena which occur in the troposphere, and in the further evaluation of the theories using experiments on physical models
Multiple scattering formulation of two-dimensional acoustic and electromagnetic metamaterials
Energy Technology Data Exchange (ETDEWEB)
Torrent, Daniel; Sanchez-Dehesa, Jose, E-mail: datorma1@upvnet.upv.es, E-mail: jsdehesa@upvnet.upv.es [Grupo de Fenomenos Ondulatorios, Departamento de IngenierIa Electronica, Universitat Politecnica de Valencia, Camino de Vera s/n (Edificio 7F), ES-46022 Valencia (Spain)
2011-09-15
A multiple scattering formulation of two-dimensional (2D) acoustic metamaterials is presented. This approach is comprehensive and can lead to frequency-dependent effective parameters (scalar bulk modulus and tensorial mass density), as it is possible to have not only positive or negative ellipsoidal refractive index, but also positive or negative hyperbolic refractive index. The correction due to multiple scattering interactions is included in the theory and it is demonstrated that its contribution is important only for lattices with high filling fractions. Since the surface fields on the scatterers are mainly responsible for the anomalous behavior of the resulting effective medium, complex scatterers can be used to engineer the frequency response. Anisotropic effects are also discussed within this formulation and some numerical examples are reported. A homogenization theory is also extended to electromagnetic wave propagation in 2D lattices of dielectric structures, where Mie resonances are found to be responsible for the metamaterial behavior.
Assessment of Multiple Scattering Errors of Laser Diffraction Instruments
National Research Council Canada - National Science Library
Strakey, Peter
2003-01-01
The accuracy of two commercial laser diffraction instruments was compared under conditions of multiple scattering designed to simulate the high droplet number densities encountered in liquid propellant rocket combustors...
Multiple scattering approach to X-ray absorption spectroscopy
International Nuclear Information System (INIS)
Benfatto, M.; Wu Ziyu
2003-01-01
In this paper authors 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. Authors 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
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...
SWIMS: a small-angle multiple scattering computer code
International Nuclear Information System (INIS)
Sayer, R.O.
1976-07-01
SWIMS (Sigmund and WInterbon Multiple Scattering) is a computer code for calculation of the angular dispersion of ion beams that undergo small-angle, incoherent multiple scattering by gaseous or solid media. The code uses the tabulated angular distributions of Sigmund and Winterbon for a Thomas-Fermi screened Coulomb potential. The fraction of the incident beam scattered into a cone defined by the polar angle α is computed as a function of α for reduced thicknesses over the range 0.01 less than or equal to tau less than or equal to 10.0. 1 figure, 2 tables
Method for measuring multiple scattering corrections between liquid scintillators
Energy Technology Data Exchange (ETDEWEB)
Verbeke, J.M., E-mail: verbeke2@llnl.gov; Glenn, A.M., E-mail: glenn22@llnl.gov; Keefer, G.J., E-mail: keefer1@llnl.gov; Wurtz, R.E., E-mail: wurtz1@llnl.gov
2016-07-21
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.
Electron Raman scattering in asymmetrical multiple quantum wells
International Nuclear Information System (INIS)
Betancourt-Riera, R; Rosas, R; Marin-Enriquez, I; Riera, R; Marin, J L
2005-01-01
Optical properties of asymmetrical multiple quantum wells for the construction of quantum cascade lasers are calculated, and expressions for the electronic states of asymmetrical multiple quantum wells are presented. The gain and differential cross-section for an electron Raman scattering process are obtained. Also, the emission spectra for several scattering configurations are discussed, and the corresponding selection rules for the processes involved are studied; an interpretation of the singularities found in the spectra is given. The electron Raman scattering studied here can be used to provide direct information about the efficiency of the lasers
Scattering amplitude and shift in self-energy in medium
International Nuclear Information System (INIS)
Mallik, S.
2002-01-01
Two simple proofs are presented for the first order virial expansion of the self-energy of a particle moving through a medium, characterised by temperature and/or chemical potential(s). One is based on the virial expansion of the self-energy operator itself, while the other is based on the analysis of its Feynman diagrams in configuration space. (orig.)
Multiple scattering effects in depth resolution of elastic recoil detection
International Nuclear Information System (INIS)
Wielunski, L.S.; Harding, G.L.
1998-01-01
Elastic Recoil Detection (ERD) is used to profile hydrogen and other low mass elements in thin films at surface and interfaces in a similar way that Rutherford Backscattering Spectroscopy (RBS) is used to detect and profile heavy elements. It is often assumed that the depth resolutions of these two techniques are similar. However, in contrast to typical RBS, the depth resolution of ERD is limited substantially by multiple scattering. In experimental data analysis and/or spectra simulations of a typical RBS measurement multiple scattering effects are often ignored. Computer programs used in IBA, such as RUMP, HYPRA or RBX do not include multiple scattering effects at all. In this paper, using practical thin metal structures with films containing intentionally introduced hydrogen, we demonstrate experimental ERD depth resolution and sensitivity limitations. The effects of sample material and scattering angle are also discussed. (authors)
Multiple scattering effects in depth resolution of elastic recoil detection
Energy Technology Data Exchange (ETDEWEB)
Wielunski, L.S.; Harding, G.L. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Telecommunications and Industrial Physics; Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics, Budapest, (Hungary)
1998-06-01
Elastic Recoil Detection (ERD) is used to profile hydrogen and other low mass elements in thin films at surface and interfaces in a similar way that Rutherford Backscattering Spectroscopy (RBS) is used to detect and profile heavy elements. It is often assumed that the depth resolutions of these two techniques are similar. However, in contrast to typical RBS, the depth resolution of ERD is limited substantially by multiple scattering. In experimental data analysis and/or spectra simulations of a typical RBS measurement multiple scattering effects are often ignored. Computer programs used in IBA, such as RUMP, HYPRA or RBX do not include multiple scattering effects at all. In this paper, using practical thin metal structures with films containing intentionally introduced hydrogen, we demonstrate experimental ERD depth resolution and sensitivity limitations. The effects of sample material and scattering angle are also discussed. (authors). 19 refs., 4 figs.
On analyticity of linear waves scattered by a layered medium
Nicholls, David P.
2017-10-01
The scattering of linear waves by periodic structures is a crucial phenomena in many branches of applied physics and engineering. In this paper we establish rigorous analytic results necessary for the proper numerical analysis of a class of High-Order Perturbation of Surfaces methods for simulating such waves. More specifically, we prove a theorem on existence and uniqueness of solutions to a system of partial differential equations which model the interaction of linear waves with a multiply layered periodic structure in three dimensions. This result provides hypotheses under which a rigorous numerical analysis could be conducted for recent generalizations to the methods of Operator Expansions, Field Expansions, and Transformed Field Expansions.
Multiple scattering theory for superconducting heterostructures
Energy Technology Data Exchange (ETDEWEB)
Ujfalussy, Balazs [Wigner Research Centre for Physics, Budapest (Hungary)
2016-07-01
We generalize the screened Korringa-Kohn-Rostoker method for solving the corresponding Kohn-Sham-Bogoliubov-de Gennes equations for surfaces and interfaces. As an application of the theory, we study the quasiparticle spectrum of Au overlayers on a Nb(100) host. We find that within the superconducting gap region, the quasiparticle spectrum consists of Andreev bound states with a dispersion which is closely connected to the underlying electronic structure of the overlayer. We also find that the spectrum has a strongly k-dependent induced gap. The properties of the gap are discussed in relation to the thickness of the overlayer, and it is shown that certain states do not participate in the Andreev scattering process. From the thickness dependence of the gap size we calculate the superconducting critical temperature of Au/Nb(100) heterostructures what we compare with with experiments. Moreover, predictions are made for similar heterostructures of other compounds.
Effective response and scattering cross section of spherical inclusions in a medium
Energy Technology Data Exchange (ETDEWEB)
Alexopoulos, A., E-mail: Aris.Alexopoulos@dsto.defence.gov.a [Electronic Warfare and Radar Division, Defence Science and Technology Organisation (DSTO), PO Box 1500, Edinburgh 5111 (Australia)
2009-08-24
The Maxwell-Garnett theory for a right-handed homogeneous system is extended in order to investigate the effective response of a medium consisting of low density distributed 3-dimensional inclusions. The polarisability factor is modified to account for inclusions with binary layered volumes and it is shown that such a configuration can yield doubly negative effective permittivity and permeability. Terms representing second-order scattering interactions between binary inclusions in the medium are derived and are used to reformulate conventional effective medium theory. In the appropriate limit, the one-body theory of Maxwell-Garnett is recovered. The scattering cross section of the spherical inclusions is determined and comparison is made to homogeneous dielectric scatterers in the Rayleigh limit. It is found that the scattering resonances can be manipulated using the inclusion parameters. Furthermore, the effect that two-interacting spherical inclusions in a medium have on the scattering cross section is investigated via higher order dipole moments while the issue of reducing the scattering cross section to zero is also examined.
Lambert, Simon A.; Näsholm, Sven Peter; Nordsletten, David; Michler, Christian; Juge, Lauriane; Serfaty, Jean-Michel; Bilston, Lynne; Guzina, Bojan; Holm, Sverre; Sinkus, Ralph
2015-08-01
Wave scattering provides profound insight into the structure of matter. Typically, the ability to sense microstructure is determined by the ratio of scatterer size to probing wavelength. Here, we address the question of whether macroscopic waves can report back the presence and distribution of microscopic scatterers despite several orders of magnitude difference in scale between wavelength and scatterer size. In our analysis, monosized hard scatterers 5 μ m in radius are immersed in lossless gelatin phantoms to investigate the effect of multiple reflections on the propagation of shear waves with millimeter wavelength. Steady-state monochromatic waves are imaged in situ via magnetic resonance imaging, enabling quantification of the phase velocity at a voxel size big enough to contain thousands of individual scatterers, but small enough to resolve the wavelength. We show in theory, experiments, and simulations that the resulting coherent superposition of multiple reflections gives rise to power-law dispersion at the macroscopic scale if the scatterer distribution exhibits apparent fractality over an effective length scale that is comparable to the probing wavelength. Since apparent fractality is naturally present in any random medium, microstructure can thereby leave its fingerprint on the macroscopically quantifiable power-law exponent. Our results are generic to wave phenomena and carry great potential for sensing microstructure that exhibits intrinsic fractality, such as, for instance, vasculature.
Spin effects in medium-energy electron-3He scattering
International Nuclear Information System (INIS)
van den Brand, J.F.J.; Alarcon, R.; Bauer, T.
1998-01-01
New physics can be accessed by scattering polarized electrons from a polarized 3 He internal gas target. It is discussed how the asymmetries for the reactions 3 vector He(vector e,e'), 3 vector He(vector e,e'p), 3 vector He(vector e,e'n), 3 vector He(vector e,e'd), and 3 vector He(vector e,e'pn) may provide precise information on the S' and the D-wave parts of the 3 He ground-state wave function, the neutron form factors, and the role of spin-dependent reaction mechanism effects. The experiment uses up to 900 MeV (polarized) electrons from the AmPS storage ring in Amsterdam, Netherlands, in combination with large acceptance electron and hadron detectors. (orig.)
Correlation expansion: a powerful alternative multiple scattering calculation method
International Nuclear Information System (INIS)
Zhao Haifeng; Wu Ziyu; Sebilleau, Didier
2008-01-01
We introduce a powerful alternative expansion method to perform multiple scattering calculations. In contrast to standard MS series expansion, where the scattering contributions are grouped in terms of scattering order and may diverge in the low energy region, this expansion, called correlation expansion, partitions the scattering process into contributions from different small atom groups and converges at all energies. It converges faster than MS series expansion when the latter is convergent. Furthermore, it takes less memory than the full MS method so it can be used in the near edge region without any divergence problem, even for large clusters. The correlation expansion framework we derive here is very general and can serve to calculate all the elements of the scattering path operator matrix. Photoelectron diffraction calculations in a cluster containing 23 atoms are presented to test the method and compare it to full MS and standard MS series expansion
Simulation of multiple scattering background in heavy ion backscattering spectrometry
International Nuclear Information System (INIS)
Li, M.M.; O'Connor, D.J.
1999-01-01
With the development of heavy ion backscattering spectrometry (HIBS) for the detection of trace quantities of heavy-atom impurities on Si surfaces, it is necessary to quantify the multiple scattering contribution 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 background features for heavy ions C, Ne, Si, Ar and Kr impinging on four types of targets: (1) a single ultra-thin (free standing) Au film of 10 A thickness, (2) a 10 A Au film on a 50 A Si surface, (3) a 10 A Au film on an Si substrate (10 000 A), and (4) a thick target (10 000 A) of pure Si. The ratio of the signal from the Au thin layer to the background due to multiple scattering has been derived by fitting the simulation results. From the simulation results, it is found that the Au film contributes to the background which the Si plays a role in developing due to the ion's multiple scattering in the substrate. Such a background is generated neither by only the Au thin 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 in the Au layer and subsequently several small angle scatterings in the substrate. This study allows an appropriate choice of incident beam species and energy range when the HIBS is utilized to analyse low level impurities in Si wafers
Solution of neutron slowing down equation including multiple inelastic scattering
International Nuclear Information System (INIS)
El-Wakil, S.A.; Saad, A.E.
1977-01-01
The present work is devoted the presentation of an analytical method for the calculation of elastically and inelastically slowed down neutrons in an infinite non absorbing homogeneous medium. On the basis of the Central limit theory (CLT) and the integral transform technique the slowing down equation including inelastic scattering in terms of the Green function of elastic scattering is solved. The Green function is decomposed according to the number of collisions. A formula for the flux at any lethargy O (u) after any number of collisions is derived. An equation for the asymptotic flux is also obtained
Medium energy hadron-nucleus scattering in the 1/N expansion formalism
International Nuclear Information System (INIS)
Kuyucak, S.; Morrison, I.
1992-01-01
The algebraic-eikonal approach to the medium energy hadron-nucleus scattering is generalized to arbitrary interactions and boson types using the 1/N expansion technique for the interacting boson model. The results are used in a comparative study of proton scattering from deformed nuclei in the sd and sdg boson models. The two models give almost identical results for a pure quadrupole interaction but widely differ when a hexadecapole interaction is included. 25 refs., 3 tabs., 7 figs
Monte Carlo simulations of multiple scattering effects in ERD measurements
International Nuclear Information System (INIS)
Doyle, Barney Lee; Arstila, Kai.; Nordlumd, K.; Knapp, James Arthur
2003-01-01
Multiple scattering effects in ERD measurements are studied by comparing two Monte Carlo simulation codes, representing different approaches to obtain acceptable statistics, to experimental spectra measured from a HfO 2 sample with a time-of-flight-ERD setup. The results show that both codes can reproduce the absolute detection yields and the energy distributions in an adequate way. The effect of the choice of the interatomic potential in multiple scattering effects is also studied. Finally the capabilities of the MC simulations in the design of new measurement setups are demonstrated by simulating the recoil energy spectra from a WC x N y sample with a low energy heavy ion beam.
Multiple scattering theory of X-ray absorption. A review
International Nuclear Information System (INIS)
Fonda, L.
1991-11-01
We review the basic elements of the theory of X-ray absorption using the tools provided by the theory of multiple scattering. A momentum space approach of clear physical insight is used where the final formulas expressing EXAFS and XANES, i.e. the structures appearing in the absorption coefficient above the edge of a deep core level threshold, are given in terms of eigenstates of the photoelectron momentum. A simple graphic representation is given for the multiple scattering function. (author). 38 refs, 4 figs, 1 tab
Multiple scattering problems in heavy ion elastic recoil detection analysis
International Nuclear Information System (INIS)
Johnston, P.N.; El Bouanani, M.; Stannard, W.B.; Bubb, I.F.; Cohen, D.D.; Dytlewski, N.; Siegele, R.
1998-01-01
A number of groups use Heavy Ion Elastic Recoil Detection Analysis (HIERDA) to study materials science problems. Nevertheless, there is no standard methodology for the analysis of HIERDA spectra. To overcome this deficiency we have been establishing codes for 2-dimensional data analysis. A major problem involves the effects of multiple and plural scattering which are very significant, even for quite thin (∼100 nm) layers of the very heavy elements. To examine the effects of multiple scattering we have made comparisons between the small-angle model of Sigmund et al. and TRIM calculations. (authors)
Wang, Xuezhen; Lai, Jiancheng; Song, Yang; Li, Zhenhua
2018-05-01
It is generally recognized that circularly polarized light is preferentially maintained over linearly polarized light in turbid medium with Mie scatterers. However, in this work, the anomalous depolarization anisotropy is reported in the backscattering area near the point of illumination. Both experimental and Monte Carlo simulations show preferential retention of linear polarization states compared to circular polarization states in a specific backscattering area. Further analysis indicates that the anomalous depolarization behavior in the specific area is induced by lateral scattering events, which own low circular polarization memory. In addition, it is also found that the size of the anomalous depolarization area is related to the transport mean free path of the turbid medium.
Energy Technology Data Exchange (ETDEWEB)
Sun Wenbo E-mail: w.sun@larc.nasa.gov; Loeb, Norman G.; Fu Qiang
2004-02-01
A recently developed finite-difference time domain scheme is examined using the exact analytic solutions for light scattering by a coated sphere immersed in an absorbing medium. The relative differences are less than 1% in the extinction, scattering, and absorption efficiencies and less than 5% in the scattering phase functions. The definition of apparent single-scattering properties is also discussed.
Elastic scattering of protons at the nucleus 6He in the Glauber multiple scattering theory
International Nuclear Information System (INIS)
Prmantayeva, B.A.; Temerbayev, A.A.; Tleulessova, I.K.; Ibrayeva, E.T.
2011-01-01
Calculation is submitted for the differential cross sections of elastic p 6 He-scattering at energies of 70 and 700 MeV/nucleon within the framework of the Glauber theory of multiple diffraction scattering. We used the three-particle wave functions: α-n-n with realistic intercluster potentials. The sensitivity of elastic scattering to the proton-nuclear interaction and the structure of nuclei had been investigated. It is shown that the contribution of small components of the wave function as well as the multiplicity of the scattering operator Ω should be considered to describe a cross-section in broad angular range . A comparison with available experimental data was made. (author)
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
2017-05-28
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.
Proton-Nucleus Elastic Cross Sections Using Two-Body In-Medium Scattering Amplitudes
Tripathi, R. K.; Wilson, John W.; Cucinotta, Francis A.
2001-01-01
Recently, a method was developed of extracting nucleon-nucleon (NN) cross sections in the medium directly from experiment. The in-medium NN cross sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the Langley Research Center. The ratio of the real to the imaginary part of the two-body scattering amplitude in the medium was investigated. These ratios are used in combination with the in-medium NN cross sections to calculate elastic proton-nucleus cross sections. The agreement is excellent with the available experimental data. These cross sections are needed for the radiation risk assessment of space missions.
Nonlinear light scattering in a two component medium: optical limiting application
International Nuclear Information System (INIS)
Joudrier, Valerie
1998-01-01
Scattering is a fundamental manifestation of the interaction between matter and radiation, resulting from inhomogeneities in the refractive index, which decrease transmission. This phenomenon is then especially attractive for sensor protection from laser light by optical limiting. One of the methods to induce scattering at high incident energy is to make use of the Kerr effect where the index of refraction is intensity dependent. Thus, the idea is to use a two component medium with a good index matching between the two components at low intensity, resulting in the medium transparency, and to modify it, at high intensity, due to the non linearity of one component making the medium highly scattering. Some of the experimental and theoretical investigations concerning a new material (here, a cell containing some liquid with small silica particles as inclusion in it) are presented in the visible domain (I=532 nm), for the nanosecond protection regime, beginning, with the chemical synthesis of the sample. The experimental results concerning the optical limiting process are presented, showing that nonlinear scattering is clearly the dominant mechanism in confrontation with other potential nonlinear effects. Several complementary experiments are then performed to complete the nonlinear scattering characterization, involving the measurement of the angular distribution of scattered energy and the integrating sphere measurement. Further information are also gained by studying the time response of the nonlinearities with a dual-beam (pulsed-pump, cw probe) technique. The previous experimental data is also analyzed with some simple theoretical models to evaluate the nonlinearity of the material from optical limiting, the angular scattering and the total scattering energy measurements. The good match between all the analytical results permits to delineate the physical mechanisms responsible for the nonlinear scattering effect and to direct the final conclusion. (author) [fr
Multiple scattering and attenuation corrections in Deep Inelastic Neutron Scattering experiments
International Nuclear Information System (INIS)
Dawidowski, J; Blostein, J J; Granada, J R
2006-01-01
Multiple scattering and attenuation corrections in Deep Inelastic Neutron Scattering experiments are analyzed. The theoretical basis of the method is stated, and a Monte Carlo procedure to perform the calculation is presented. The results are compared with experimental data. The importance of the accuracy in the description of the experimental parameters is tested, and the implications of the present results on the data analysis procedures is examined
Imaging moving objects from multiply scattered waves and multiple sensors
International Nuclear Information System (INIS)
Miranda, Analee; Cheney, Margaret
2013-01-01
In this paper, we develop a linearized imaging theory that combines the spatial, temporal and spectral components of multiply scattered waves as they scatter from moving objects. In particular, we consider the case of multiple fixed sensors transmitting and receiving information from multiply scattered waves. We use a priori information about the multipath background. We use a simple model for multiple scattering, namely scattering from a fixed, perfectly reflecting (mirror) plane. We base our image reconstruction and velocity estimation technique on a modification of a filtered backprojection method that produces a phase-space image. We plot examples of point-spread functions for different geometries and waveforms, and from these plots, we estimate the resolution in space and velocity. Through this analysis, we are able to identify how the imaging system depends on parameters such as bandwidth and number of sensors. We ultimately show that enhanced phase-space resolution for a distribution of moving and stationary targets in a multipath environment may be achieved using multiple sensors. (paper)
High-energy expansion for nuclear multiple scattering
International Nuclear Information System (INIS)
Wallace, S.J.
1975-01-01
The Watson multiple scattering series is expanded to develop the Glauber approximation plus systematic corrections arising from three (1) deviations from eikonal propagation between scatterings, (2) Fermi motion of struck nucleons, and (3) the kinematic transformation which relates the many-body scattering operators of the Watson series to the physical two-body scattering amplitude. Operators which express effects ignored at the outset to obtain the Glauber approximation are subsequently reintroduced via perturbation expansions. Hence a particular set of approximations is developed which renders the sum of the Watson series to the Glauber form in the center of mass system, and an expansion is carried out to find leading order corrections to that summation. Although their physical origins are quite distinct, the eikonal, Fermi motion, and kinematic corrections produce strikingly similar contributions to the scattering amplitude. It is shown that there is substantial cancellation between their effects and hence the Glauber approximation is more accurate than the individual approximations used in its derivation. It is shown that the leading corrections produce effects of order (2kR/subc/) -1 relative to the double scattering term in the uncorrected Glauber amplitude, hk being momentum and R/subc/ the nuclear char []e radius. The leading order corrections are found to be small enough to validate quatitative analyses of experimental data for many intermediate to high energy cases and for scattering angles not limited to the very forward region. In a Gaussian model, the leading corrections to the Glauber amplitude are given as convenient analytic expressions
Medium energy inelastic proton-nucleus scattering with spin dependent NN interaction
International Nuclear Information System (INIS)
Ahmad, I.; Auger, J.P.
1981-12-01
The previously proposed effective profile expansion method for the Glauber multiple scattering model calculation has been extended to the case of proton-nucleus inelastic scattering with spin dependent NN interaction. Using the method which turns out to be computationally simple and of relatively wider applicability, a study of sensitivity of proton-nucleus inelastic scattering calculation to the sometimes neglected momentum transfer dependence of the NN scattering amplitude has been made. We find that the calculated polarization is particularly sensitive in this respect. (author)
Multiple scattering in synchrotron studies of disordered materials
International Nuclear Information System (INIS)
Poulsen, H.F.; Neuefeind, J.
1995-01-01
A formalism for the multiple scattering and self-absorption in synchrotron studies of disordered materials is presented. The formalism goes beyond conventionally used approximations and treat the cross sections, the beam characteristics, the state of polarization, and the electronic correction terms in full. Using hard X-rays it is shown how the simulated distributions can be directly compared to experimental data. ((orig.))
Scattering and extinction by spherical particles immersed in an absorbing host medium
Mishchenko, Michael I.; Dlugach, Janna M.
2018-05-01
Many applications of electromagnetic scattering involve particles immersed in an absorbing rather than lossless medium, thereby making the conventional scattering theory potentially inapplicable. To analyze this issue quantitatively, we employ the FORTRAN program developed recently on the basis of the first-principles electromagnetic theory to study far-field scattering by spherical particles embedded in an absorbing infinite host medium. We further examine the phenomenon of negative extinction identified recently for monodisperse spheres and uncover additional evidence in favor of its interference origin. We identify the main effects of increasing the width of the size distribution on the ensemble-averaged extinction efficiency factor and show that negative extinction can be eradicated by averaging over a very narrow size distribution. We also analyze, for the first time, the effects of absorption inside the host medium and ensemble averaging on the phase function and other elements of the Stokes scattering matrix. It is shown in particular that increasing absorption significantly suppresses the interference structure and can result in a dramatic expansion of the areas of positive polarization. Furthermore, the phase functions computed for larger effective size parameters can develop a very deep minimum at side-scattering angles bracketed by a strong diffraction peak in the forward direction and a pronounced backscattering maximum.
Biçer, M.; Kaşkaş, A.
2018-03-01
The infinite medium Green's function is used to solve the half-space albedo, slab albedo and Milne problems for the unpolarized Rayleigh scattering case; these problems are the most classical problems of radiative transfer theory. The numerical results are obtained and are compared with previous ones.
Perturbation theory for the effective diffusion constant in a medium of random scatterers
International Nuclear Information System (INIS)
Dean, D S; Drummond, I T; Horgan, R R; Lefevre, A
2004-01-01
We develop perturbation theory and physically motivated resummations of the perturbation theory for the problem of a tracer particle diffusing in a random medium. The random medium contains point scatterers of density ρ uniformly distributed throughout the material. The tracer is a Langevin particle subjected to the quenched random force generated by the scatterers. Via our perturbative analysis, we determine when the random potential can be approximated by a Gaussian random potential. We also develop a self-similar renormalization group approach based on thinning out the scatterers; this scheme is similar to that used with success for diffusion in Gaussian random potentials and agrees with known exact results. To assess the accuracy of this approximation scheme, its predictions are confronted with results obtained by numerical simulation
Continuum multiple-scattering approach to electron-molecule scattering and molecular photoionization
International Nuclear Information System (INIS)
Dehmer, J.L.; Dill, D.
1979-01-01
The multiple-scattering approach to the electronic continuum of molecules is described. The continuum multiple-scattering model (CMSM) was developed as a survey tool and, as such was required to satisfy two requirements. First, it had to have a very broad scope, which means (i) molecules of arbitrary geometry and complexity containing any atom in the periodic system, (ii) continuum electron energies from 0-1000 eV, and (iii) capability to treat a large range of processes involving both photoionization and electron scattering. Second, the structure of the theory was required to lend itself to transparent, physical interpretation of major spectral features such as shape resonances. A comprehensive theoretical framework for the continuum multiple scattering method is presented, as well as its applications to electron-molecule scattering and molecular photoionization. Highlights of recent applications in these two areas are reviewed. The major impact of the resulting studies over the last few years has been to establish the importance of shape resonances in electron collisions and photoionization of practically all (non-hydride) molecules
Renormalized multiple-scattering theory of photoelectron diffraction
International Nuclear Information System (INIS)
Biagini, M.
1993-01-01
The current multiple-scattering cluster techniques for the calculation of x-ray photoelectron and Auger-electron diffraction patterns consume much computer time in the intermediate-energy range (200--1000 eV); in fact, because of the large value of the electron mean free path and of the large forward-scattering amplitude at such energies, the electron samples a relatively large portion of the crystal, so that the number of paths to be considered becomes dramatically high. An alternative method is developed in the present paper: instead of calculating the individual contribution from each single path, the scattering matrix of each plane parallel to the surface is calculated with a renormalization process that calculates every scattering event in the plane up to infinite order. Similarly the scattering between two planes is calculated up to infinite order, and the double-plane scattering matrix is introduced. The process may then be applied to the calculation of a larger set of atomic layers. The advantage of the method is that a relatively small number of internuclear vectors have been used to obtain convergence in the calculation
Charged particle multiplicities in deep inelastic scattering at HERA
International Nuclear Information System (INIS)
Aid, S.; Anderson, M.; Andreev, V.
1996-08-01
Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastic e + p 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. (orig.)
SWIMS, Sigmund and Winterbon Multiple Scattering of Ion Beams
International Nuclear Information System (INIS)
Eyeberger, L.
1999-01-01
1 - Description of program or function - SWIMS calculates the angular dispersion of ion beams that undergo small-angle, incoherent multiple scattering by gaseous or solid media. 2 - Method of solution - SWIMS uses the tabulated angular distributions of Sigmund and Winterbon for a Thomas-Fermi screened Coulomb potential. The fraction of the incident beam scattered into a cone defined by the polar angle is computed as a function of that angle for a reduced thickness over the rang of 0.01 to 10
International Nuclear Information System (INIS)
Moufekkir, F.; Moussaoui, M.A.; Mezrhab, A.; Naji, H.; Lemonnier, D.
2012-01-01
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 (ε ι ), 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.
MCRTOF, Multiple Scattering of Resonance Region Neutron in Time of Flight Experiments
International Nuclear Information System (INIS)
Ohkubo, Mako
1984-01-01
1 - Description of program or function: Multiple scattering of neutrons in the resonance energy region impinging on a disk with an arbitrary angle. 2 - Method of solution: The Monte Carlo method is employed to simulate the path of an incident neutron in a medium for which macroscopic cross sections are determined by resonance parameters. By tracing a large number of neutrons, probabilities for capture, transmission, front-face scattering, rear-face scattering and side-face scattering are determined and printed out as function of incident neutron energy. Optionally, the distribution of capture locations in the disk can be printed. The incident neutron energy is swept to fit a situation as encountered in time-of-flight experiments. 3 - Restrictions on the complexity of the problem: The cross section file is constructed from input resonance parameters with a single- level Breit-Wigner formula. The following restrictions and simplifications apply: - The maximum number of resonances is five. - Reactions other than capture and scattering are neglected. - The angular scattering distribution in the center-of-mass system is assumed to be uniform. - Chemical binding effects are neglected
Coastal Zone Color Scanner atmospheric correction algorithm - Multiple scattering effects
Gordon, Howard R.; Castano, Diego J.
1987-01-01
Errors due to multiple scattering which are expected to be encountered in application of the current Coastal Zone Color Scanner (CZCS) atmospheric correction algorithm are analyzed. The analysis is based on radiative transfer computations in model atmospheres, in which the aerosols and molecules are distributed vertically in an exponential manner, with most of the aerosol scattering located below the molecular scattering. A unique feature of the analysis is that it is carried out in scan coordinates rather than typical earth-sun coordinates, making it possible to determine the errors along typical CZCS scan lines. Information provided by the analysis makes it possible to judge the efficacy of the current algorithm with the current sensor and to estimate the impact of the algorithm-induced errors on a variety of applications.
Electromagnetic imaging of multiple-scattering small objects: non-iterative analytical approach
International Nuclear Information System (INIS)
Chen, X; Zhong, Y
2008-01-01
Multiple signal classification (MUSIC) imaging method and the least squares method are applied to solve the electromagnetic inverse scattering problem of determining the locations and polarization tensors of a collection of small objects embedded in a known background medium. Based on the analysis of induced electric and magnetic dipoles, the proposed MUSIC method is able to deal with some special scenarios, due to the shapes and materials of objects, to which the standard MUSIC doesn't apply. After the locations of objects are obtained, the nonlinear inverse problem of determining the polarization tensors of objects accounting for multiple scattering between objects is solved by a non-iterative analytical approach based on the least squares method
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.
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.
Interstitial integrals in the multiple-scattering model
International Nuclear Information System (INIS)
Swanson, J.R.; Dill, D.
1982-01-01
We present an efficient method for the evaluation of integrals involving multiple-scattering wave functions over the interstitial region. Transformation of the multicenter interstitial wave functions to a single center representation followed by a geometric projection reduces the integrals to products of analytic angular integrals and numerical radial integrals. The projection function, which has the value 1 in the interstitial region and 0 elsewhere, has a closed-form partial-wave expansion. The method is tested by comparing its results with exact normalization and dipole integrals; the differences are 2% at worst and typically less than 1%. By providing an efficient means of calculating Coulomb integrals, the method allows treatment of electron correlations using a multiple scattering basis set
Ultrasound scatter in heterogeneous 3D microstructures: Parameters affecting multiple scattering
Engle, B. J.; Roberts, R. A.; Grandin, R. J.
2018-04-01
This paper reports on a computational study of ultrasound propagation in heterogeneous metal microstructures. Random spatial fluctuations in elastic properties over a range of length scales relative to ultrasound wavelength can give rise to scatter-induced attenuation, backscatter noise, and phase front aberration. It is of interest to quantify the dependence of these phenomena on the microstructure parameters, for the purpose of quantifying deleterious consequences on flaw detectability, and for the purpose of material characterization. Valuable tools for estimation of microstructure parameters (e.g. grain size) through analysis of ultrasound backscatter have been developed based on approximate weak-scattering models. While useful, it is understood that these tools display inherent inaccuracy when multiple scattering phenomena significantly contribute to the measurement. It is the goal of this work to supplement weak scattering model predictions with corrections derived through application of an exact computational scattering model to explicitly prescribed microstructures. The scattering problem is formulated as a volume integral equation (VIE) displaying a convolutional Green-function-derived kernel. The VIE is solved iteratively employing FFT-based con-volution. Realizations of random microstructures are specified on the micron scale using statistical property descriptions (e.g. grain size and orientation distributions), which are then spatially filtered to provide rigorously equivalent scattering media on a length scale relevant to ultrasound propagation. Scattering responses from ensembles of media representations are averaged to obtain mean and variance of quantities such as attenuation and backscatter noise levels, as a function of microstructure descriptors. The computational approach will be summarized, and examples of application will be presented.
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.)
Multiple-scattering theory. New developments and applications
International Nuclear Information System (INIS)
Ernst, Arthur
2007-01-01
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.)
Multiple-scattering analysis of laser-beam propagation in the atmosphere and through obscurants
International Nuclear Information System (INIS)
Zardecki, A.; Gerstl, S.A.W.
1983-01-01
The general purpose, discrete-ordinates transport code TWOTRAN is applied to describe the propagation and multiple scattering of a laser beam in a nonhomogeneous aerosol medium. For the medium composed of smoke, haze, and a rain cloud, the problem of the target detectability in a realistic atmospheric scenario is addressed and solved. The signals reflected from the target vs the signals scattered from the smoke cloud are analyzed as a function of the smoke concentration. By calculating the average intensity and a correction factor in the x-y and r-z geometries, the consistency of the rectangular and cylindrical geometry models is assessed. Received power for a detector with a small field of view is computed on a sphere of 1-km radius around the laser source for the Air Force Geophysics Laboratory rural aerosol model with extinction coefficients of 4 km - 1 and 10 km - 1 . This computation allows us to study the received power as a function of the angle between the detector and source axes. The correction factor describing the multiple-scattering enhancement with respect to the simple Lambert-Beer law is introduced, and its calculation is employed to validate the use of the small-angle approximation for the transmissometer configuration. An outline of the theory for a finite field of view detector is followed by numerical results pertaining to the received power and intensity for various aerosol models. Recommendations regarding future work are also formulated
The factorization method for inverse acoustic scattering in a layered medium
International Nuclear Information System (INIS)
Bondarenko, Oleksandr; Kirsch, Andreas; Liu, Xiaodong
2013-01-01
In this paper, we consider a problem of inverse acoustic scattering by an impenetrable obstacle embedded in a layered medium. We will show that the factorization method can be applied to recover the embedded obstacle; that is, the equation F-tilde g =φ z is solvable if and only if the sampling point z is in the interior of the unknown obstacle. Here, F-tilde is a self-adjoint operator related to the far field operator and ϕ z is the far field pattern of the Green function with respect to the problem of scattering by the background medium for point z. The validity of the factorization method is proven with the help of a mixed reciprocity principle and an application of the scattering operator. Due to the established mixed reciprocity principle, knowledge of the Green function for the background medium is no longer required, which makes the method attractive from the computational point of view. The paper is only concerned with sound-soft obstacles, but the analysis can be easily extended for sound-hard obstacles, or obstacles with separated sound-soft and sound-hard parts. Finally, we provide an explicit example for a radially symmetric case and present some numerical examples. (paper)
Kuo, C. P.; Yang, P.; Huang, X.; Feldman, D.; Flanner, M.; Kuo, C.; Mlawer, E. J.
2017-12-01
Clouds, which cover approximately 67% of the globe, serve as one of the major modulators in adjusting radiative energy on the Earth. Since rigorous radiative transfer computations including multiple scattering are costly, only absorption is considered in the longwave spectral bands in the radiation sub-models of the general circulation models (GCMs). Quantification of the effect of ignoring longwave scattering for flux and heating rate simulations is performed by using the GCM version of the Longwave Rapid Radiative Transfer Model (RRTMG_LW) with an implementation with the 16-stream Discrete Ordinates Radiative Transfer (DISORT) Program for a Multi-Layered Plane-Parallel Medium in conjunction with the 2010 CCCM products that merge satellite observations from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), the CloudSat, the Clouds and the Earth's Radiant Energy System (CERES) and the Moderate Resolution Imaging Spectrometer (MODIS). One-year global simulations show that neglecting longwave scattering overestimates upward flux at the top of the atmosphere (TOA) and underestimates downward flux at the surface by approximately 2.63 and 1.15 W/m2, respectively. Furthermore, when longwave scattering is included in the simulations, the tropopause is cooled by approximately 0.018 K/day and the surface is heated by approximately 0.028 K/day. As a result, the radiative effects of ignoring longwave scattering and doubling CO2 are comparable in magnitude.
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.
International Nuclear Information System (INIS)
Mayers, J.; Cywinski, R.
1985-03-01
Some of the approximations commonly used for the analytical estimation of multiple scattering corrections to thermal neutron elastic scattering data from cylindrical and plane slab samples have been tested using a Monte Carlo program. It is shown that the approximations are accurate for a wide range of sample geometries and scattering cross-sections. Neutron polarisation analysis provides the most stringent test of multiple scattering calculations as multiply scattered neutrons may be redistributed not only geometrically but also between the spin flip and non spin flip scattering channels. A very simple analytical technique for correcting for multiple scattering in neutron polarisation analysis has been tested using the Monte Carlo program and has been shown to work remarkably well in most circumstances. (author)
Medium modified two-body scattering amplitude from proton-nucleus total cross-sections
Tripathi, R. K.; Wilson, J. W.; Cucinotta, F. A.
2001-01-01
Recently (R.K. Tripathi, J.W. Wilson, F.A. Cucinotta, Nucl. Instr. and Meth. B 145 (1998) 277; R.K. Tripathi, F.A. Cucinotta, J.W. Wilson, NASA-TP-1998-208438), we have extracted nucleon-nucleon (N-N) cross-sections in the medium directly from experiment. The in-medium N-N cross-sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the NASA Langley Research Center. Here, we investigate the ratio of real to imaginary part of the two-body scattering amplitude in the medium. These ratios are used in combination with the in-medium N-N cross-sections to calculate total proton-nucleus cross-sections. The agreement is excellent with the available experimental data. These cross-sections are needed for the radiation risk assessment of space missions. c2001 Elsevier Science B.V. All rights reserved.
Multiple Scattering Approach to Continuum State with Generally Shaped Potential
International Nuclear Information System (INIS)
Hatada, Keisuke; Hayakawa, Kuniko; Tenore, Antonio; Benfatto, Maurizio; Natoli, Calogero
2007-01-01
We present a new scheme for solving the scattering problem for an arbitrarily shaped potential cell that avoids the well known convergence problems in the angular momentum expansion of the cell shape function. Tests of the method against analytically soluble separable model potentials, with and without shape truncation, have been performed with success. By a judicious choice of the shape of the cells partitioning the whole molecular space and use of empty cells when necessary, we set up a multiple scattering scheme that leads to a straightforward generalization of the same equations in the muffin-tin approximation. For example lmax in the angular momentum expansion can still be chosen according to the rule lmax ∼ kR, where R is the radius of the bounding sphere of the cell and all the matrices appearing in the theory are square matrices
Hatada, Keisuke; Ebert, Hubert
2018-01-01
This edited book, based on material presented at the EU Spec Training School on Multiple Scattering Codes and the following MSNano Conference, is divided into two distinct parts. The first part, subtitled “basic knowledge”, provides the basics of the multiple scattering description in spectroscopies, enabling readers to understand the physics behind the various multiple scattering codes available for modelling spectroscopies. The second part, “extended knowledge”, presents “state- of-the-art” short chapters on specific subjects associated with improving of the actual description of spectroscopies within the multiple scattering formalism, such as inelastic processes, or precise examples of modelling.
Microscopic study of elastic and inelastic ALPHA-nucleus scattering at medium energies
International Nuclear Information System (INIS)
Dao Tien Khoa; Hoang Si Than; Do Cong Cuong; Ngo Van Luyen; Nguyen Ngoc Quynh; Nguyen Tuan Anh
2007-01-01
Analyses of the inelastic α + 12 C scattering at medium energies have indicated that the strength of the Hoyle state (the isoscalar O 2 + excitation at 7.65 MeV in 12 C) seems to exhaust only 7 to 9% of the monopole energy weighted sum rule (EWSR), compared to about 15% of the EWSR extracted from inelastic electron scattering data. The full monopole transition strength predicted by realistic microscopic α-cluster models of the Hoyle state can be shown to exhaust up to 22% of the EWSR. To explore the missing monopole strength in the inelastic α + 12 C scattering, we have performed a fully microscopic folding model analysis of the inelastic α + 12 C scattering at E lab =104 to 240 MeV using the 3-α resonating group wave function of the Hoyle state obtained by Kamimura, and a complex density-dependent M3Y interaction newly parametrized based on the Brueckner Hartree Fock results for nuclear matter. Our folding model analysis has shown consistently that the missing monopole strength of the Hoyle state is not associated with the uncertainties in the analysis of the α + 12 C scattering, but is most likely due to the short lifetime and weakly bound structure of this state which significantly enhances absorption in the exit α + 12 C * (O 2 + ) channel. (author)
Quantitative considerations in medium energy ion scattering depth profiling analysis of nanolayers
Energy Technology Data Exchange (ETDEWEB)
Zalm, P.C.; Bailey, P. [International Institute for Accelerator Applications, University of Huddersfield, Queensgate, Huddersfield HD1 3DH (United Kingdom); Reading, M.A. [Physics and Materials Research Centre, University of Salford, Salford M5 4WT (United Kingdom); Rossall, A.K. [International Institute for Accelerator Applications, University of Huddersfield, Queensgate, Huddersfield HD1 3DH (United Kingdom); Berg, J.A. van den, E-mail: j.vandenberg@hud.ac.uk [International Institute for Accelerator Applications, University of Huddersfield, Queensgate, Huddersfield HD1 3DH (United Kingdom)
2016-11-15
The high depth resolution capability of medium energy ion scattering (MEIS) is becoming increasingly relevant to the characterisation of nanolayers in e.g. microelectronics. In this paper we examine the attainable quantitative accuracy of MEIS depth profiling. Transparent but reliable analytical calculations are used to illustrate what can ultimately be achieved for dilute impurities in a silicon matrix and the significant element-dependence of the depth scale, for instance, is illustrated this way. Furthermore, the signal intensity-to-concentration conversion and its dependence on the depth of scattering is addressed. Notably, deviations from the Rutherford scattering cross section due to screening effects resulting in a non-coulombic interaction potential and the reduction of the yield owing to neutralization of the exiting, backscattered H{sup +} and He{sup +} projectiles are evaluated. The former mainly affects the scattering off heavy target atoms while the latter is most severe for scattering off light target atoms and can be less accurately predicted. However, a pragmatic approach employing an extensive data set of measured ion fractions for both H{sup +} and He{sup +} ions scattered off a range of surfaces, allows its parameterization. This has enabled the combination of both effects, which provides essential information regarding the yield dependence both on the projectile energy and the mass of the scattering atom. Although, absolute quantification, especially when using He{sup +}, may not always be achievable, relative quantification in which the sum of all species in a layer adds up to 100%, is generally possible. This conclusion is supported by the provision of some examples of MEIS derived depth profiles of nanolayers. Finally, the relative benefits of either using H{sup +} or He{sup +} ions are briefly considered.
An integral for second-order multiple scattering perturbation theory
International Nuclear Information System (INIS)
Hoffman, G.G.
1997-01-01
This paper presents the closed form evaluation of a six-dimensional integral. The integral arises in the application to many-electron systems of a multiple scattering perturbation expansion at second order when formulated in fourier space. The resulting function can be used for the calculation of both the electron density and the effective one-electron potential in an SCF calculations. The closed form expression derived here greatly facilitates these calculations. In addition, the evaluated integral can be used for the computation of second-order corrections to the open-quotes optimized Thomas-Fermi theory.close quotes 10 refs., 2 figs
Angular distribution of diffuse reflectance from incoherent multiple scattering in turbid media.
Gao, M; Huang, X; Yang, P; Kattawar, G W
2013-08-20
The angular distribution of diffuse reflection is elucidated with greater understanding by studying a homogeneous turbid medium. We modeled the medium as an infinite slab and studied the reflection dependence on the following three parameters: the incident direction, optical depth, and asymmetry factor. The diffuse reflection is produced by incoherent multiple scattering and is solved through radiative transfer theory. At large optical depths, the angular distribution of the diffuse reflection with small incident angles is similar to that of a Lambertian surface, but, with incident angles larger than 60°, the angular distributions have a prominent reflection peak around the specular reflection angle. These reflection peaks are found originating from the scattering within one transport mean free path in the top layer of the medium. The maximum reflection angles for different incident angles are analyzed and can characterize the structure of angular distributions for different asymmetry factors and optical depths. The properties of the angular distribution can be applied to more complex systems for a better understanding of diffuse reflection.
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
Muon energy estimate through multiple scattering with the MACRO detector
Energy Technology Data Exchange (ETDEWEB)
Ambrosio, M.; Antolini, R.; 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.; Nicolo, 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.; Raino, A.; Reynoldson, J.; Ronga, F.; Rrhioua, A.; Satriano, C.; Scapparone, E. E-mail: eugenio.scapparone@bo.infn.it; Scholberg, K.; Sciubba, A.; Serra, P.; Sioli, M. E-mail: maximiliano.sioli@bo.infn.it; 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
2002-10-21
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 reconstruct the muon energy for E{sub {mu}}<40 GeV. The test beam data provide an absolute energy calibration, which allows us to apply this method to MACRO data.
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...
A new three-dimensional track fit with multiple scattering
Energy Technology Data Exchange (ETDEWEB)
Berger, Niklaus; Kozlinskiy, Alexandr [Physikalisches Institut, Heidelberg University, Heidelberg (Germany); Institut für Kernphysik and PRISMA cluster of excellence, Mainz University, Mainz (Germany); Kiehn, Moritz; Schöning, André [Physikalisches Institut, Heidelberg University, Heidelberg (Germany)
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.
A new three-dimensional track fit with multiple scattering
International Nuclear Information System (INIS)
Berger, Niklaus; Kozlinskiy, Alexandr; Kiehn, Moritz; Schöning, André
2017-01-01
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 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.
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.
Scattering by a spherical inhomogeneity in a fluid-saturated porous medium
International Nuclear Information System (INIS)
Berryman, J.G.
1985-01-01
A fast compressional wave incident on an inhomogeneity in a fluid-saturated porous medium will produce three scattered elastic waves: a fast compressional wave, a slow compressional wave, and a shear wave. This problem is formulated as a multipole expansion using Biot's equations of poroelasticity. The solution for the first term (n = 0) in the multipole series involves a 4 x 4 system which is solved analytically in the long-wavelength limit. All higher-order terms (n > or = 1) require the solution of a 6 x 6 system. A procedure for solving these equations by splitting the problem into a 4 x 4 system and a 2 x 2 system and then iterating is introduced. The first iterate is just the solution of the elastic wave scattering problem in the absence of fluid effects. Higher iterates include the successive perturbation effects of fluid/solid interaction
Aspects of frequency redistribution for non-coherent scattering in a turbulent medium
International Nuclear Information System (INIS)
Magnan, C.
1975-01-01
The scattering of line phonons in a turbulent medium is re-examined. The fact is taken into account that a photon absorbed in a turbulent element having some velocity will be re-emitted by the same element and keeps in that way a certain 'memory' of its absorption. Adding the contributions of all turbulent elements at a given point new redistribution functions are constructed, describing this correlation. They give the probability that a photon with frequency x in the direction n is absorbed and re-emitted at frequency x' in the direction n'. A preliminary discussion of the problem is given in an astrophysical context. (author)
Structural characterization of CdSe/ZnS quantum dots using medium energy ion scattering
Sortica, M. A.; Grande, P. L.; Radtke, C.; Almeida, L. G.; Debastiani, R.; Dias, J. F.; Hentz, A.
2012-07-01
In the present work, we have analyzed CdSe/ZnS core-shell quantum dots by medium energy ion scattering (MEIS), which is a powerful technique to explore the synthesis, formation, stability, and elemental distribution of such core-shell structures, along with other auxiliary analytical techniques. By comparing different quantum-dot structural models spectra with the experimental MEIS data, we were able to obtain some sample structural information. We found that, despite the well known non stoichiometric Cd:Se ratio, the core is stoichiometric, and there is an excess of cadmium distributed in the shell.
Study of the sensitivity of the radiation transport problem in a scattering medium
International Nuclear Information System (INIS)
Nunes, Rogerio Chaffin
2002-03-01
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)
International Nuclear Information System (INIS)
Nakagawa, Masayuki; Ishiguro, Yukio; Tokuno, Yukio.
1978-01-01
The self-shielding factors for elastic removal cross sections of light and medium weight nuclides were calculated for the parameter, σ 0 within the conventional concept of the group constant sets. The numerical study were performed for obtaining a simple and accurate method. The present results were compared with the exact values and the conventional ones, and shown to be remarkably improved. It became apparent that the anisotropy of the elastic scattering did not affect to the self-shielding factors though it did to the infinite dilution cross sections. With use of the present revised set, the neutron flux were calculated in an iron medium and in a prototype FBR and compared with those by the fine spectrum calculations and the conventional set. The present set showed the considerable improvement in the vicinity of the large resonance regions of sodium, iron and oxygen. (auth.)
Scattering of elastic waves on fractures randomly distributed in a three-dimensional medium
Strizhkov, S. A.; Ponyatovskaya, V. I.
1985-02-01
The purpose of this work is to determine the variation in basic characteristics of the wave field formed in a jointed medium, such as the intensity of fluctuations of amplitude, correlation radius, scattering coefficient and frequency composition of waves, as functions of jointing parameters. Fractures are simulated by flat plates randomly distributed and chaotically oriented in a three-dimensional medium. Experiments were performed using an alabaster model, a rectangular block measuring 50 x 50 x 120 mm. The plates were introduced into liquid alabaster which was then agitated. Models made in this way contain randomly distributed and chaotically oriented fractures. The influence of these fractures appears as fluctuations in the wave field formed in the medium. The data obtained in experimental studies showed that the dimensions of heterogeneities determined by waves in the jointed medium and the dimensions of the fractures themselves coincide only if the distance between fractures is rather great. If the distance between fractures is less than the wavelength, the dimensions of the heterogeneities located by the wave depend on wavelength.
In-medium effects in K+ scattering versus Glauber model with noneikonal corrections
International Nuclear Information System (INIS)
Eliseev, S.M.; Rihan, T.H.
1996-01-01
The discrepancy between the experimental and the theoretical ratio R of the total cross sections, R=σ(K + - 12 C)/6σ(K + - d), at momenta up to 800 MeV/c is discussed in the framework of the Glauber multiple scattering approach. It is shown that various corrections such as adopting relativistic K + -N amplitudes as well as noneikonal corrections seem to fail in reproducing the experimental data especially at higher momenta. 17 refs., 1 fig
Multiple Scattering in Random Mechanical Systems and Diffusion Approximation
Feres, Renato; Ng, Jasmine; Zhang, Hong-Kun
2013-10-01
This paper is concerned with stochastic processes that model multiple (or iterated) scattering in classical mechanical systems of billiard type, defined below. From a given (deterministic) system of billiard type, a random process with transition probabilities operator P is introduced by assuming that some of the dynamical variables are random with prescribed probability distributions. Of particular interest are systems with weak scattering, which are associated to parametric families of operators P h , depending on a geometric or mechanical parameter h, that approaches the identity as h goes to 0. It is shown that ( P h - I)/ h converges for small h to a second order elliptic differential operator on compactly supported functions and that the Markov chain process associated to P h converges to a diffusion with infinitesimal generator . Both P h and are self-adjoint (densely) defined on the space of square-integrable functions over the (lower) half-space in , where η is a stationary measure. This measure's density is either (post-collision) Maxwell-Boltzmann distribution or Knudsen cosine law, and the random processes with infinitesimal generator respectively correspond to what we call MB diffusion and (generalized) Legendre diffusion. Concrete examples of simple mechanical systems are given and illustrated by numerically simulating the random processes.
International Nuclear Information System (INIS)
Shafiq, A.; Meyer, H.E. de; Grosjean, C.C.
1985-01-01
An approximate model based on an improved diffusion-type theory is established for treating multiple synthetic scattering in a homogeneous slab of finite thickness. As in the case of the exact treatment given in the preceding paper (Part I), it appears possible to transform the considered transport problem into an equivalent fictitious one involving multiple isotropic scattering, therefore permitting the application of an established corrected diffusion theory for treating isotropic scattering taking place in a convex homogeneous medium bounded by a vacuum in the presence of various types of sources. The approximate values of the reflection and transmission coefficients are compared with the rigorous values listed in Part I. In this way, the high accuracy of the approximation is clearly demonstrated. (author)
Real space multiple scattering description of alloy phase stability
International Nuclear Information System (INIS)
Turchi, P.E.A.; Sluiter, M.
1992-01-01
This paper presents a brief overview of the advanced methodology which has been recently developed to study phase stability properties of substitutional alloys, including order-disorder phenomena and structural transformations. The approach is based on the real space version of the Generalized Perturbation Method first introduced by Ducastelle and Gautier, within the Korringa-Kohn-Rostoker multiple scattering formulation of the Coherent Potential Approximation. Temperature effects are taken into account with a generalized meanfield approach, namely the Cluster Variation Method. The viability and the predictive power of such a scheme will be illustrated by a few examples, among them: the ground state properties of alloys, in particular the ordering tendencies for a series of equiatomic bcc-based alloys, the computation of alloy phase diagrams with the case of fcc and bcc-based Ni-Al alloys, the calculation of antiphase boundary energies and interfacial energies, and the stability of artificial ordered superlattices
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.
Radiation of ultrarelativistic charge taking into account for multiple scattering
International Nuclear Information System (INIS)
Yang, C.
1977-01-01
A brief theoretical review of characteristics of X-rays and more hard radiation formed by an ultrarelativistic charged particle passing through a plate or a stack of plates with regard for multiple scattering and the plate material absorptivity is made. Formulas for frequency- angular and frequency distributions of total radiation in the cases of a plate and of a stack of plates with large spacings as well as a stack of sufficiently thick plates are given. A calculation method for the radiation distributions in a general case of an arbitrary stack is pointed out. The frequency distribution of the total radiation consisting of bremsstrahlung and boundary effects is analyzed in detail. A problem of experimental separation of the boundary effect from the total radiation is discussed
Multiple scattering of slow muons in an electron gas
International Nuclear Information System (INIS)
Archubi, C.D.; Arista, N.R.
2017-01-01
A comparative study of the angular dispersion of slow muons in an electron gas is performed using 3 dielectric models which represent the case of metals (Lindhard model for a free electron gas) and the cases of semiconductors and insulators (Levine and Louie model and Brandt and Reinheimer model for systems with a band gap) and a non-linear model for both cases at very low velocities. The contribution of collective electronic excitations according to the dielectric model are found to be negligible. The results from the calculation using Lindhard expressions for the angular half width are consistent with the result of a multiple scattering model. In particular, the effects produced by the band gap of the material are analyzed in detail. Finally, as the recoil effect is negligible, there is an almost exact scaling, for a given velocity, between the proton and the muon results. (authors)
Study of the multiple scattering effect in TEBENE using the Monte Carlo method
International Nuclear Information System (INIS)
Singkarat, Somsorn.
1990-01-01
The neutron time-of-flight and energy spectra, from the TEBENE set-up, have been calculated by a computer program using the Monte Carlo method. The neutron multiple scattering within the polyethylene scatterer ring is closely investigated. The results show that multiple scattering has a significant effect on the detected neutron yield. They also indicate that the thickness of the scatterer ring has to be carefully chosen. (author)
Aethalometer multiple scattering correction Cref for mineral dust aerosols
Directory of Open Access Journals (Sweden)
C. Di Biagio
2017-08-01
Full Text Available 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
Hentz, A; Parkinson, G S; Quinn, P D; Muñoz-Márquez, M A; Woodruff, D P; Grande, P L; Schiwietz, G; Bailey, P; Noakes, T C Q
2009-03-06
The energy spectrum associated with scattering of 100 keV H+ ions from the outermost few atomic layers of Cu(111) in different scattering geometries provides direct evidence of trajectory-dependent electronic energy loss. Theoretical simulations, combining standard Monte Carlo calculations of the elastic scattering trajectories with coupled-channel calculations to describe inner-shell ionization and excitation as a function of impact parameter, reproduce the effects well and provide a means for far more complete analysis of medium-energy ion scattering data.
Angular distribution of scattered electron and medium energy electron spectroscopy for metals
International Nuclear Information System (INIS)
Oguri, Takeo; Ishioka, Hisamichi; Fukuda, Hisashi; Irako, Mitsuhiro
1986-01-01
The angular distribution (AD) of scattered electrons produced by medium energy incident electrons (E P = 50 ∼ 300 eV) from polycrystalline Ti, Fe, Ni, Cu and Au were obtained by the angle-resolved medium energy electron spectrometer. The AD of the energy loss peaks are similar figures to AD of the elastically reflected electron peaks. Therefore, the exchanged electrons produced by the knock-on collision between the incident electrons and those of metals without momentum transfer are observed as the energy loss spectra (ELS). This interpretation differs from the inconsequent interpretation by the dielectric theory or the interband transition. The information depth and penetration length are obtained from AD of the Auger electron peaks. The contribution of the surface to spectra is 3 % at the maximum for E P = 50 eV. The true secondary peaks representing the secondary electron emission spectroscopy (SES) are caused by the emissions of the energetic electrons (kT e ≥ 4 eV), and SES is the inversion of ELS. The established fundamental view is that the medium energy electron spectra represent the total bulk density of states. (author)
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).
Ion-induced particle desorption in time-of-flight medium energy ion scattering
Lohmann, S.; Primetzhofer, D.
2018-05-01
Secondary ions emitted from solids upon ion impact are studied in a time-of-flight medium energy ion scattering (ToF-MEIS) set-up. In order to investigate characteristics of the emission processes and to evaluate the potential for surface and thin film analysis, experiments employing TiN and Al samples were conducted. The ejected ions exhibit a low initial kinetic energy of a few eV, thus, requiring a sufficiently high acceleration voltage for detection. Molecular and atomic ions of different charge states originating both from surface contaminations and the sample material are found, and relative yields of several species were determined. Experimental evidence that points towards a predominantly electronic sputtering process is presented. For emitted Ti target atoms an additional nuclear sputtering component is suggested.
International Nuclear Information System (INIS)
Chen, Xudong
2010-01-01
This paper proposes a version of the subspace-based optimization method to solve the inverse scattering problem with an inhomogeneous background medium where the known inhomogeneities are bounded in a finite domain. Although the background Green's function at each discrete point in the computational domain is not directly available in an inhomogeneous background scenario, the paper uses the finite element method to simultaneously obtain the Green's function at all discrete points. The essence of the subspace-based optimization method is that part of the contrast source is determined from the spectrum analysis without using any optimization, whereas the orthogonally complementary part is determined by solving a lower dimension optimization problem. This feature significantly speeds up the convergence of the algorithm and at the same time makes it robust against noise. Numerical simulations illustrate the efficacy of the proposed algorithm. The algorithm presented in this paper finds wide applications in nondestructive evaluation, such as through-wall imaging
In-medium scaling law and electron scattering from high-spin states in 208Pb
International Nuclear Information System (INIS)
Arias de Saavedra, F.; Lallena, A.M.
1994-01-01
The effects of the environment modifications in the structure of the low-lying high-spin states of 208 Pb are studied by analyzing how the in-medium scaling law works on the excitation energies, wave functions, and electron scattering form factors corresponding to these states. It is shown that the consideration of f π * in addition to the effective ρ-meson mass does not affect too much most of the states analyzed. However, some of them appear to be extremely sensitive to its inclusion in the residual nucleon-nucleon interaction. As a result, a value of m ρ * /m ρ ∼f π * /f π ∼0.91 gives a good description of the (e,e') form factors of these particular states without any quenching factor. This value is in agreement with the one found for 48 Ca in a similar analysis performed in a previous work
Multiple-scattering formalism for correlated systems: A KKR-DMFT approach
International Nuclear Information System (INIS)
Minar, J.; Perlov, A.; Ebert, H.; Chioncel, L.; Katsnelson, M. I.; Lichtenstein, A.I.
2005-01-01
We present a charge and self-energy self-consistent computational scheme for correlated systems based on the Korringa-Kohn-Rostoker (KKR) multiple scattering theory with the many-body effects described by the means of dynamical mean field theory (DMFT). The corresponding local multiorbital and energy dependent self-energy is included into the set of radial differential equations for the single-site wave functions. The KKR Green's function is written in terms of the multiple scattering path operator, the later one being evaluated using the single-site solution for the t-matrix that in turn is determined by the wave functions. An appealing feature of this approach is that it allows to consider local quantum and disorder fluctuations on the same footing. Within the coherent potential approximation (CPA) the correlated atoms are placed into a combined effective medium determined by the DMFT self-consistency condition. Results of corresponding calculations for pure Fe, Ni, and Fe x Ni 1-x alloys are presented
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...
Medium energy nucleon-nucleus scattering theory by semi-classical distorted wave approximation
Energy Technology Data Exchange (ETDEWEB)
Ogata, Kazuyuki [Kyushu Univ., Fukuoka (Japan)
1998-07-01
The semiclassical distorted wave model (SCDW) is one of the quantum mechanical models for nucleon inelastic and charge exchange scattering at intermediate energies. SCDW can reproduce the double differential inclusive cross sections for multi-step direct processes quite well in the angular and outgoing energy regions where the model is expected to work. But the model hitherto assumed on-the-energy-shell (on-shell) nucleon-nucleon scattering in the nucleus, neglecting the difference in the distorting potentials for the incoming and the outgoing particles and also the Q-value in the case of (p,n) reactions. There had also been a problem in the treatment of the exchange of colliding nucleons. Now we modify the model to overcome those problems and put SCDW on sounder theoretical foundations. The modification results in slight reduction (increase) of double differential cross sections at forward (backward) angles. We also examine the effect of the in-medium modification of N-N cross sections in SCDW and find it small. A remedy of the disagreement at very small and large angles in terms of the Wigner transform of the single particle density matrix is also discussed. This improvement gives very promising results. (author)
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.
International Nuclear Information System (INIS)
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-SP 3 equation based reconstruction algorithm for bioluminescence tomography was proposed in this paper. In the algorithm, the third-order simplified spherical harmonics approximation (SP 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
Measurements and applications of neutron multiple scattering in resonance region
International Nuclear Information System (INIS)
Ohkubo, Makio
1977-02-01
Capture yield of neutrons impinging on a thick material is complicated due to self-shielding and multiple scattering, especially in the resonance region. When the incident neutron energy is equal to a resonance energy of the material, capture probability of the neutron increases with sample thickness and reaches a saturation value P sub(CO). There is a simple relation between P sub(CO) and GAMMA sub(n)/GAMMA and the recoil energy by the Monte-Carlo calculation. To examine validity of the relation, P sub(CO) was measured for 19 resonances in 12 nuclides with thick samples, using a JAERI linac time-of-flight spectrometer with Moxon-Rae type gamma ray detector and transmission type neutron flux monitor. Results of the measurements confirmed the validity. With this relation, the GAMMA sub(n)/GAMMA or GAMMA sub(γ)/GAMMA value can be obtained from the measured P sub(CO), and also the level spins be determined by combining the transmission data. Because of the definition of P sub(CO), determination of the resonance parameters is not sensitive to the sample thickness as far as it is sufficiently thick. (auth.)
Multiple-scattering theory with a truncated basis set
International Nuclear Information System (INIS)
Zhang, X.; Butler, W.H.
1992-01-01
Multiple-scattering theory (MST) is an extremely efficient technique for calculating the electronic structure of an assembly of atoms. The wave function in MST is expanded in terms of spherical waves centered on each atom and indexed by their orbital and azimuthal quantum numbers, l and m. The secular equation which determines the characteristic energies can be truncated at a value of the orbital angular momentum l max , for which the higher angular momentum phase shifts, δ l (l>l max ), are sufficiently small. Generally, the wave-function coefficients which are calculated from the secular equation are also truncated at l max . Here we point out that this truncation of the wave function is not necessary and is in fact inconsistent with the truncation of the secular equation. A consistent procedure is described in which the states with higher orbital angular momenta are retained but with their phase shifts set to zero. We show that this treatment gives smooth, continuous, and correctly normalized wave functions and that the total charge density calculated from the corresponding Green function agrees with the Lloyd formula result. We also show that this augmented wave function can be written as a linear combination of Andersen's muffin-tin orbitals in the case of muffin-tin potentials, and can be used to generalize the muffin-tin orbital idea to full-cell potentals
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?.
Multiple scattering approach to the vibrational excitation of molecules by slow electrons
International Nuclear Information System (INIS)
Drukarev, G.
1976-01-01
Another approach to the problem of vibrational excitation of homonuclear two-atomic molecules by slow electrons possibly accompanied by rotational transitions is presented based on the picture of multiple scattering of an electron inside the molecule. The scattering of two fixed centers in the zero range potential model is considered. The results indicate that the multiple scattering determines the order of magnitude of the vibrational excitation cross sections in the energy region under consideration even if the zero range potential model is used. Also the connection between the multiple scattering approach and quasi-stationary molecular ion picture is established. 9 refs
Absorption in multiple scattering systems of coated spheres: design applications
International Nuclear Information System (INIS)
Stout, Brian; Andraud, Christine; Stout, Sophie; Lafait, Jacques
2003-01-01
We illustrate the utility of some recently derived transfer matrix methods for electromagnetic scattering calculations in systems composed of coated spherical scatterers. Any of the spherical coatings, cores, or host media may be composed of absorbing materials. Our formulae permit the calculation of local absorption in either orientation fixed or orientation averaged situations. We introduce methods for estimating the macroscopic transport properties of such media, and show how our scattering calculations can permit 'design' optimization of macroscopic properties
Evanescent wave scattering at off-axis incidence on multiple cylinders located near a surface
International Nuclear Information System (INIS)
Lee, Siu-Chun
2015-01-01
The scattering characteristics of an infinite cylinder are strongly influenced by the incidence angle relative to its axis. If the incident wave propagates in the plane normal to the axis of the cylinder, the polarization of the scattered wave remains unchanged and the scattered wave propagates in the same plan as the incident wave. At off-axis incidence such that the incident direction makes an oblique angle with the cylinder axis, the scattered wave is depolarized, and its spatial distribution becomes three-dimensional. This paper presents the scattering solution for oblique incidence on multiple parallel cylinders located near a planar interface by an evanescent wave that is generated by total internal reflection of the source wave propagating in the higher refractive index substrate. Hertz potentials are utilized to formulate the interaction of inhomogeneous waves with the cylinders, scattering at the substrate interface, and near field scattering between the cylinders. Analytic formulas are derived for the electromagnetic fields and Poynting vector of scattered radiation in the near-field and their asymptotic forms in the far-field. Numerical examples are shown to illustrate scattering of evanescent wave by multiple cylinders at off-axis incidence. - Highlights: • Developed an exact solution for off-axis incidence on multiple cylinders. • Included depolarization, near-field scattering, and Fresnel effect in theory. • Derived analytic formulas for scattered radiation in the far field. • Illustrated evanescent scattering at off-axis incidence by numerical data
International Nuclear Information System (INIS)
Margetan, F.J.; Haldipur, Pranaam; Yu Linxiao; Thompson, R.B.
2005-01-01
For pulse/echo inspections of metals, models which predict backscattered noise characteristics often make a 'single-scattering' assumption, i.e., multiple-scattering events in which sound is scattered from one grain to another before returning to the transducer are ignored. Models based on the single-scattering assumption have proven to be very useful in simulating inspections of engine-alloy billets and forgings. However, this assumption may not be accurate if grain scattering is too 'strong' (e.g., if the mean grain diameter and/or the inspection frequency is too large). In this work, backscattered grain noise measurements and analyses were undertaken to search for evidence of significant multiple scattering in pulse/echo inspections of jet-engine Nickel alloys. At or above about 7 MHz frequency and 50 micron grain diameter, problems were seen with single-scattering noise models that are likely due to the neglect of multiple scattering by the models. The modeling errors were less severe for focused-probe measurements in the focal zone than for planar probe inspections. Single-scattering noise models are likely adequate for simulating current billet inspections which are carried out using 5-MHz focused transducers. However, multiple scattering effects should be taken into account in some fashion when simulating higher-frequency inspections of Nickel-alloy billets having large mean grain diameters (> 40 microns)
Exact multiple scattering theory of two-nucleus collisions including the Pauli principle
International Nuclear Information System (INIS)
Gurvitz, S.A.
1981-01-01
Exact equations for two-nucleus scattering are derived in which the effects of the Pauli principle are fully included. Our method exploits a modified equation for the scattering of two identical nucleons, which is obtained at the beginning. Considering proton-nucleus scattering we found that the resulting amplitude has two components, one resembling a multiple scattering series for distinguishable particles, and the other a distorted (A-1) nucleon cluster exchange. For elastic pA scattering the multiple scattering amplitude is found in the form of an optical potential expansion. We show that the Kerman-McManus-Thaler theory of the optical potential could be easily modified to include the effects of antisymmetrization of the projectile with the target nucleons. Nucleus-nucleus scattering is studied first for distinguishable target and beam nucleus. Afterwards the Pauli principle is included, where only the case of deuteron-nucleus scattering is discussed in detail. The resulting amplitude has four components. Two of them correspond to modified multiple scattering expansions and the others are distorted (A-1)- and (A-2)- nucleon cluster exchange. The result for d-A scattering is extended to the general case of nucleus-nucleus scattering. The equations are simple to use and as such constitute an improvement over existing schemes
Comparison of Geant4 multiple Coulomb scattering models with theory for radiotherapy protons.
Makarova, Anastasia; Gottschalk, Bernard; Sauerwein, Wolfgang
2017-07-06
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 Molière/Fano/Hanson variant of Molière theory (Gottschalk et al 1993 Nucl. Instrum. Methods Phys. Res. B 74 467-90). For transverse spreading of the beam in the target itself, the theory of Preston and Koehler (Gottschalk (2012 arXiv:1204.4470)) 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.
Single and multiple electromagnetic scattering by dielectric obstacles from a resonance perspective
International Nuclear Information System (INIS)
Riley, D.J.
1987-03-01
A new application of the singularity expansion method (SEM) is explored. This application combines the classical theory of wave propagation through a multiple-scattering environment and the SEM. Because the SEM is generally considered to be a theory for describing surface currents on conducting scatters, extensions are made which permit, under certain conditions, a singularity expansion representation for the electromagnetic field scattered by a dielectric scatterer. Application of this expansion is then made to the multiple-scattering case using both single and multiple interactions. A resonance scattering tensor form is used for the SEM description which leds to an associated tensor form for the solution to the multiple-scattering problem with each SEM pole effect appearing explicitly. The coherent field is determined for both spatial and SEM parameter random variations. A numerical example for the case of an ensemble of dielectric spheres which possess frequency-dependent loss is also made. Accurate resonance expansions for the single-scattering problem are derived, and resonance trajectories based on the Debye relaxation model for the refractive index are introduced. Application of these resonance expansions is then made to the multiple-scattering results for a slab containing a distribution of spheres with varying radii. Conditions are discussed which describe when the hybrid theory is appropriate. 53 refs., 21 figs., 9 tabs
International Nuclear Information System (INIS)
Jayaswal, B.; Mazumder, S.
1998-09-01
Small-angle scattering data from strong scattering systems, e.g. porous materials, cannot be analysed invoking single scattering approximation as specimen needed to replicate the bulk matrix in essential properties are too thick to validate the approximation. The presence of multiple scattering is indicated by invalidity of the functional invariance property of the observed scattering profile with variation of sample thickness and/or wave length of the probing radiation. This article delineates how non accounting of multiple scattering affects the results of analysis and then how to correct the data for its effect. It deals with an algorithm to extract single scattering profile from small-angle scattering data affected by multiple scattering. The algorithm can process the scattering data and deduce single scattering profile in absolute scale. A software package, SIMSAS, is introduced for executing this inversion step. This package is useful both to simulate and to analyse multiple small-angle scattering data. (author)
Elastic and quasielastic scattering of light nuclei in the theory of multiple scattering
International Nuclear Information System (INIS)
Ismatov, E.I.; Kuterbekov, K.A.; Dzhuraev, Sh.Kh.; Ehsaniyazov, Sh.P.; Zholdasova, S.M.
2005-01-01
In the work the calculation method for diffraction scattering amplitudes of light nuclei by heavy nuclei is developed. For A 1 A 2 -scattering effects of pair-, three-fold, and four-fold screenings are estimated. It is shown, that in amplitude calculations for A 1 A 2 elastic scattering it is enough come to nothing more than accounting of total screenings in the first order. Analysis of nucleus-nucleus scattering sensitive characteristics to choice of single-particle nuclear densities parametrization is carried out
Multiple scattering of polarized light: comparison of Maxwell theory and radiative transfer theory.
Voit, Florian; Hohmann, Ansgar; Schäfer, Jan; Kienle, Alwin
2012-04-01
For many research areas in biomedical optics, information about scattering of polarized light in turbid media is of increasing importance. Scattering simulations within this field are mainly performed on the basis of radiative transfer theory. In this study a polarization sensitive Monte Carlo solution of radiative transfer theory is compared to exact Maxwell solutions for all elements of the scattering Müller matrix. Different scatterer volume concentrations are modeled as a multitude of monodisperse nonabsorbing spheres randomly positioned in a cubic simulation volume which is irradiated with monochromatic incident light. For all Müller matrix elements effects due to dependent scattering and multiple scattering are analysed. The results are in overall good agreement between the two methods with deviations related to dependent scattering being prominent for high volume concentrations and high scattering angles.
International Nuclear Information System (INIS)
Xiong, Chuan; Shi, Jiancheng
2014-01-01
To date, the light scattering models of snow consider very little about the real snow microstructures. The ideal spherical or other single shaped particle assumptions in previous snow light scattering models can cause error in light scattering modeling of snow and further cause errors in remote sensing inversion algorithms. This paper tries to build up a snow polarized reflectance model based on bicontinuous medium, with which the real snow microstructure is considered. The accurate specific surface area of bicontinuous medium can be analytically derived. The polarized Monte Carlo ray tracing technique is applied to the computer generated bicontinuous medium. With proper algorithms, the snow surface albedo, bidirectional reflectance distribution function (BRDF) and polarized BRDF can be simulated. The validation of model predicted spectral albedo and bidirectional reflectance factor (BRF) using experiment data shows good results. The relationship between snow surface albedo and snow specific surface area (SSA) were predicted, and this relationship can be used for future improvement of snow specific surface area (SSA) inversion algorithms. The model predicted polarized reflectance is validated and proved accurate, which can be further applied in polarized remote sensing. -- Highlights: • Bicontinuous random medium were used for real snow microstructure modeling. • Photon tracing technique with polarization status tracking ability was applied. • SSA–albedo relationship of snow is close to that of sphere based medium. • Validation of albedo and BRDF showed good results. • Validation of polarized reflectance showed good agreement with experiment data
Multiple pole in the electron--hydrogen-atom scattering amplitude
International Nuclear Information System (INIS)
Amusia, M.Y.; Kuchiev, M.Y.
1982-01-01
It is demonstrated that the amplitude for electron--hydrogen-atom forward scattering has the third-order pole at the point E = -13.6 eV, E being the energy of the incident electron. The coefficients which characterize the pole are calculated exactly. The invalidity of the Born approximation is proved. The contribution of the pole singularity to the dispersion relation for the scattering amplitude is discussed
Strain relaxation of CdTe on Ge studied by medium energy ion scattering
Energy Technology Data Exchange (ETDEWEB)
Pillet, J.C., E-mail: jean-christophe.pillet@cea.fr [Univ. Grenoble Alpes, CEA, LETI, MINATEC campus, F38000 Grenoble (France); CEA, LETI, Département Optique et Photonique, F38054 Grenoble (France); Pierre, F. [Univ. Grenoble Alpes, CEA, LETI, MINATEC campus, F38000 Grenoble (France); CEA, LETI, Service de Caractérisation des Matériaux et Composants, F38054 Grenoble (France); Jalabert, D. [Univ. Grenoble Alpes, CEA, LETI, MINATEC campus, F38000 Grenoble (France); CEA-INAC/UJF-Grenoble 1 UMR-E, SP2M, LEMMA, Minatec Grenoble F-38054 (France)
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.
International Nuclear Information System (INIS)
Papiez, L.; Moskvin, V.; Tulovsky, V.
2001-01-01
The process of angular-spatial evolution of multiple scattering of charged particles can be described by a special case of Boltzmann integro-differential equation called Lewis equation. The underlying stochastic process for this evolution is the compound Poisson process on the surface of the unit sphere. The significant portion of events that constitute compound Poisson process that describes multiple scattering have diffusional character. This property allows to analyze the process of angular-spatial evolution of multiple scattering of charged particles as combination of soft and hard collision processes and compute appropriately its transition densities. These computations provide a method of the approximate solution to the Lewis equation. (orig.)
International Nuclear Information System (INIS)
Tarvainen, Tanja; Vauhkonen, Marko; Kolehmainen, Ville; Arridge, Simon R; Kaipio, Jari P
2005-01-01
In this paper, a coupled radiative transfer equation and diffusion approximation model is extended for light propagation in turbid medium with low-scattering and non-scattering regions. The light propagation is modelled with the radiative transfer equation in sub-domains in which the assumptions of the diffusion approximation are not valid. The diffusion approximation is used elsewhere in the domain. The two equations are coupled through their boundary conditions and they are solved simultaneously using the finite element method. The streamline diffusion modification is used to avoid the ray-effect problem in the finite element solution of the radiative transfer equation. The proposed method is tested with simulations. The results of the coupled model are compared with the finite element solutions of the radiative transfer equation and the diffusion approximation and with results of Monte Carlo simulation. The results show that the coupled model can be used to describe photon migration in turbid medium with low-scattering and non-scattering regions more accurately than the conventional diffusion model
Density of states calculations and multiple-scattering theory for photons
International Nuclear Information System (INIS)
Moroz, A.
1994-05-01
The density of states for a finite or an infinite cluster of scatterers in the case of both, electrons and photons, can be represented in a general form as the sum over all Krein-Friedel contributions of individual scatterers and a contribution due to the presence of multiple scatterers. The latter is given by the sum over all periodic orbits between different scatterers. General three dimensional multiple-scattering theory for electromagnetic waves in the presence of scatterers of arbitrary shape is presented. Vector structure constants are calculated and general rules for obtaining them from known scalar structure constants are given. The KKR equations for photons are explicitly written down. (author). 22 refs., 2 figs
Gong, Z; Hu, R H; Shou, Y R; Qiao, B; Chen, C E; He, X T; Bulanov, S S; Esirkepov, T Zh; Bulanov, S V; Yan, X Q
2017-01-01
γ-ray flash generation in near-critical-density target irradiated by four symmetrical colliding 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 counterpropagating laser, the accelerated electron is trapped in the electromagnetic standing waves or the ponderomotive potential well created by the coherent overlapping of the laser pulses, and emits γ-ray photons in a multiple-laser-scattering regime, where electrons act as a medium transferring energy from the laser to γ rays in the ponderomotive potential valley.
Optimum track fitting in the presence of multiple scattering
International Nuclear Information System (INIS)
Lutz, G.
1987-06-01
A method for track fitting is proposed which attempts to be as close as possible to the real track along the full path length. This is done by the introduction of scattering planes in which the particle is allowed to change its direction. A fit over the full track length includes the probability of direction change by scattering. Using matrix notation a fairly simple formalism for error estimation has been developed. Results of this method are compared to those of more widely used procedures for 'typical' examples of High Energy Spectrometers. (orig.)
Eikonal multiple scattering model within the framework of Feynman's positron theory
International Nuclear Information System (INIS)
Tekou, A.
1986-07-01
The Bethe Salpeter equation for nucleon-nucleon, nucleon-nucleus and nucleus-nucleus scattering is eikonalized. Multiple scattering series is obtained. Contributions of three body interations are included. The model presented below may be used to investigate atomic collisions. (author)
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...
Wireless Power Transmission via Sheet Medium Using Automatic Phase Adjustment of Multiple Inputs
Matsuda, Takashi; Oota, Toshifumi; Kado, Youiti; Zhang, Bing
The wireless power transmission via sheet medium is a novel physical form of communication that utilizes the surface as a medium to provide both data and power transmission services. To efficiently transmit a relatively-large amount of electric power (several watts), we have developed a wireless power transmission system via sheet medium that concentrates the electric power on a specific spot by using phase control of multiple inputs. However, to find the optimal phases of the multiple inputs making the microwave converge on a specific spot in the sheet medium, the prior knowledge of the device's position, and the pre-experiment measuring the output power, are needed. In wireless communication area, it is known that the retrodirective array scheme can efficiently transmit the power in a self-phasing manner, which uses the pilot signals sent by the client devices. In this paper, we apply the retrodirective array scheme to the wireless power transmission system via sheet medium, and propose a power transmission scheme using the phase-adjustment of multiple inputs. To confirm the effectiveness of the proposal scheme, we evaluate its performance by computer simulation and realistic measurement. Both results show that the proposal scheme can achieve the retrodirectivity over the wireless power transmission via sheet medium.
Multiple scattering theory for non-local and multichannel potentials
Czech Academy of Sciences Publication Activity Database
Natoli, C.R.; Krüger, P.; Hatada, K.; Hayakawa, K.; Sébilleau, D.; Šipr, Ondřej
2012-01-01
Roč. 24, č. 36 (2012), s. 1-20 ISSN 0953-8984 Institutional research plan: CEZ:AV0Z10100521 Keywords : multichannel scattering * correlation s * density matrix Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.355, year: 2012
Application of multiple scattering theory in electron dosimetry
International Nuclear Information System (INIS)
Oliveira, M.J.G.S. de.
1984-01-01
A theoretical model, based on the Fermi-Eyges scattering theory, which takes into account the different heterogeneous media, is proposed. Heterogeneous phantoms were built in order to obtain curves of distribution of the absorbed dose. The agreement between the theoretical and experimental data prove that presented theory model is useful to describe the absorbed dose in homogeneous media. (M.A.C.) [pt
High resolution medium energy ion scattering study of silicon oxidation and oxy nitridation
International Nuclear Information System (INIS)
Gusev, E.P.; Lu, H.C.; Garfunkel, E.; Gustafsson, T.
1998-01-01
Full text: Silicon oxide is likely to remain the material of choice for gate oxides in microelectronics for the foreseeable future. As device become ever smaller and faster, the thickness of these layers in commercial products is predicted to be less than 50 Angstroms in just a few years. An understanding of such devices will therefore likely to be based on microscopic concepts and should now be investigated by atomistic techniques. With medium energy ion scattering (MEIS) using an electrostatic energy analyzer, depth profiling of thin (<60 Angstroms) silicon oxide films on Si(100) with 3 - 5 Angstroms depth resolution in the near region has been done. The growth mechanism of thin oxide films on Si(100) has been studied, using sequential oxygen isotope exposures. It is found that the oxide films are stoichiometric to within approx. 10 Angstroms of the interface. It is also found that the oxidation reactions occur at the surface, in the transition region and at interface, with only the third region being included in the conventional (Deal-Grove) model for oxide formation. Nitrogen is sometimes added to gate oxides, as it has been found empirically that his improves some of the electrical properties. The role, location and even the amount of nitrogen that exists in such films are poorly understood, and represent interesting analytical challenges. MEIS data will be presented that address these questions, measured for a number of different processing conditions. We have recently demonstrated how to perform nitrogen nano-engineering in such ultrathin gate dielectrics, and these results will also be discussed
Continuum and bound electronic wavefunctions for anisotropic multiple-scattering potentials
International Nuclear Information System (INIS)
Siegel, J.; Dill, D.; Dehmer, J.L.
1975-01-01
Standard multiple-scattering treatments of bound and continuum one-electron states are restricted to a monopole potential in each of the various spherical regions. We have extended the treatment within these regions to a general potential. The corresponding multiple-scattering equations should facilitate accurate treatment of effects of the build-up of charge due to bonding, of the dipole character of polar molecules, and of external fields
Multiple scattering corrections to the Beer-Lambert law. 1: Open detector.
Tam, W G; Zardecki, A
1982-07-01
Multiple scattering corrections to the Beer-Lambert law are analyzed by means of a rigorous small-angle solution to the radiative transfer equation. Transmission functions for predicting the received radiant power-a directly measured quantity in contrast to the spectral radiance in the Beer-Lambert law-are derived. Numerical algorithms and results relating to the multiple scattering effects for laser propagation in fog, cloud, and rain are presented.
Effects of multiple scattering and atmospheric aerosol on the polarization of the twilight sky
International Nuclear Information System (INIS)
Ugolnikov, Oleg S.; Postylyakov, Oleg V.; Maslov, Igor A.
2004-01-01
The paper presents a review of a number of wide-angle polarization CCD-measurements of the twilight sky in V and R color bands with effective wavelengths 550 and 700nm. The basic factors affecting (usually decreasing) the polarization of the twilight sky are the atmospheric aerosol scattering and multiple scattering. These effects were distinguished from each other, and a method of multiple-scattering separation is discussed. The results are compared with the data of numerical simulation of radiative transfer in the atmosphere for different aerosol models. The whole twilight period is divided into different stages with different mechanisms forming the twilight-sky polarization properties
[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.
Concise formulation of the three-dimensional multiple-scattering theory.
Oyhenart, Laurent; Vignéras, Valérie
2012-08-01
The scattering of an electromagnetic wave by a set of dielectric and metallic spheres is a well-known physical problem. We show a mathematical simplification of the multiple-scattering theory. In this paper, we will establish the multiple-scattering equation in two different ways. Through the study of the equation form, we can choose the simplest spherical wave expansion for calculations. Then, we propose concise expressions of the Mie scattering coefficients and translation coefficients for both polarizations. With these simplified expressions, large spheres are studied without loss of accuracy. Far-field expressions, cross-sections, and the scattering matrix are also simplified. Thus, we obtain formulas that can be easily understood from a physical point of view.
International Nuclear Information System (INIS)
Peterson, G.A.
1977-10-01
Tune-up experiments were carried out at the Bates Linear Accelerator of Middleton, Massachusetts, on the 180 0 electron scattering apparatus designed and constructed by the University of Massachusetts under contract E(11-1)-2545. This apparatus serves as adjunct equipment to the Bates dispersion-matching spectrometer. Form factors were measured for the low-lying states of 27 Al over the momentum transfer range from 0.7 to 2.6 fm -1 . A paper was published in the Physical Review on low-momentum transfer elastic electron scattering from 3 He. The 3 He rms radius was determined to be 1.89 +- 0.05 fm from measurements made at the National Bureau of Standards over the momentum transfer range-squared between 0.032 and 0.34 fm -2 . A Physical Review paper was published in November, 1977, on the results of elastic electron scattering from 25 Mg over the momentum transfer range from 0.19 to 2.56 fm -1 at both forward and backward angles. Values of all of the ground-state multipole moments of both Coulomb and magnetic character were obtained. A paper was submitted for publication on the electroexcitation of giant dipole and quadrupole resonances in 20 Ne. Electric dipole and quadrupole strength was found throughout the region from 12.5 through 25 MeV. About 65% and 100% of the energy-weighted dipole and quadrupole sum rules, respectively, were exhausted. A preliminary run was made on 42 Ca and 44 Ca at the National Bureau of Standards for an incident electron energy of 54.3 MeV and a 145 0 scattering angle in an attempt to observe f/sub 7 / 2 / to f/sub 5 / 2 / magnetic dipole transitions. A paper was composed on the 160 0 inelastic scattering of electrons from 58 Ni at momentum transfers near 2 fm -1 . Strong M8 transitions were observed which are characterized by predominantly one particle--one hole excitations characterized by the configuration
Multiple scattering in closely packed systems of arbitrary non-overlapping shapes
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Keister, B.D.
1982-11-01
It has long been known that the multiple scattering of waves from a system of obstacles of finite extent can be described completely with a knowledge of the on-shell amplitudes of the individual scatterers, provided that the minimally enclosing spheres concentric with the scattering centers do not overlap. In this paper, it is shown that on-shell amplitudes alone suffice for a wider class of scattering configurations, in which the individual scatterers do not overlap, but their geometries do not satisfy the above condition. These extended geometries require a careful treatment of certain partial wave sums. An example is also discussed in which a pair of non-overlapping scatterers requires more than the on-shell amplitudes for a solution
Culture medium and growth regulators on in vitro multiplication of Psidium guajava L.
Directory of Open Access Journals (Sweden)
Jorge Vilchez
2014-01-01
Full Text Available Guava (Psidium guajava L. cultivar `Dwarf Cuban Red 18-40 EEA' has high yields. For large-scale propagation, micropropagation is a possible solution. The aim of this study was to determine the effect of two culture media, two cytokinins and an analog brasinoesteoides (DI-31 in the in vitro multiplication of this cultivar. Two culture media (MS and WPM, three concentrations of benzylaminopurine (BAP (0.5, 1.0, 1.5 mg l-1, three of kinetin (0.5, 1.0, 1.5 mg l-1 and two DI-31 (0.01 and 0.02 mg l-1 were evaluated. The variables evaluated were: number of shoots, number of leaves, shoot length and multiplication coefficient. It was found that the type of culture medium influenced the shoot multiplication of guava. The number of shoots, shoot length and multiplication coefficient were determined by the type and concentration of cytokinin added to the culture medium. With the use of WPM culture medium with 1 mg l-1 BAP It was obtained the highest values of the variables evaluated. The use of DI-31 promoted the shoot growth without affecting the multiplication coefficient. Key words: benzylaminopurine, DI-31, kinetin, guava, micropropagation, multiplication phase
Flesia, C.; Schwendimann, P.
1992-01-01
The contribution of the multiple scattering to the lidar signal is dependent on the optical depth tau. Therefore, the radar analysis, based on the assumption that the multiple scattering can be neglected is limited to cases characterized by low values of the optical depth (tau less than or equal to 0.1) and hence it exclude scattering from most clouds. Moreover, all inversion methods relating lidar signal to number densities and particle size must be modified since the multiple scattering affects the direct analysis. The essential requests of a realistic model for lidar measurements which include the multiple scattering and which can be applied to practical situations follow. (1) Requested are not only a correction term or a rough approximation describing results of a certain experiment, but a general theory of multiple scattering tying together the relevant physical parameter we seek to measure. (2) An analytical generalization of the lidar equation which can be applied in the case of a realistic aerosol is requested. A pure analytical formulation is important in order to avoid the convergency and stability problems which, in the case of numerical approach, are due to the large number of events that have to be taken into account in the presence of large depth and/or a strong experimental noise.
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.
Inelastic multiple scattering of interacting bosons in weak random potentials
International Nuclear Information System (INIS)
Geiger, Tobias
2013-01-01
Within the present thesis we develop a diagrammatic scattering theory for interacting bosons in a three-dimensional, weakly disordered potential. Based on a microscopic N-body scattering theory, we identify the relevant diagrams including elastic and inelastic collision processes that are sufficient to describe quantum transport in the regime of weak disorder. By taking advantage of the statistical properties of the weak disorder potential, we demonstrate how the N-body dynamics can be reduced to a nonlinear integral equation of Boltzmann type for the single-particle diffusive flux. A presently available alternative description - based on the Gross-Pitaevskii equation - only includes elastic collisions. In contrast, we show that far from equilibrium the presence of inelastic collisions - even for weak interaction strength - must be accounted for and can induce the full thermalization of the single-particle current. In addition, we also determine the coherent corrections to the incoherent transport, leading to the effect of coherent backscattering. For the first time, we are able to analyze the influence of inelastic collisions on the coherent backscattering signal, which lead to an enhancement of the backscattered cone in a narrow spectral window, even for increasing non-linearity. With a short recollection of the presently available experimental techniques we furthermore show how an immediate implementation of our suggested setup with confined Bose-Einstein condensates can be accomplished. Thereby, the emergence of collective and/or thermodynamic behavior from fundamental, microscopic constituents can also be assessed experimentally. In a second part of this thesis, we present first results for light scattering off strongly interacting Rydberg atoms trapped in a one-dimensional, chain-like configuration. In order to monitor the time-dependence of this interacting many-body system, we devise a weak measurement scenario for which we derive a master equation for the
Multiple parton scattering in nuclei: heavy quark energy loss and modified fragmentation functions
International Nuclear Information System (INIS)
Zhang Benwei; Wang, Enke; Wang Xinnian
2005-01-01
Multiple scattering, induced radiative energy loss and modified fragmentation functions of a heavy quark in nuclear matter are studied within the framework of generalized factorization in perturbative QCD. Modified heavy quark fragmentation functions and energy loss are derived in detail with illustration of the mass dependencies of the Landau-Pomeranchuk-Migdal interference effects and heavy quark energy loss. Due to the quark mass dependence of the gluon formation time, the nuclear size dependencies of nuclear modification of the heavy quark fragmentation function and heavy quark energy loss are found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss of the heavy quark is also significantly suppressed due to limited cone of gluon radiation imposed by the mass. Medium modification of the heavy quark fragmentation functions is found to be limited to the large z region due to the form of heavy quark fragmentation functions in vacuum
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Dodonoy, A.I.; Mashkova, E.S.; Molchanov, V.A.
1989-01-01
This paper is the third part of our review surface scattering. Part I, which was devoted to the scattering of ions by the surfaces of disordered solids, was published in 1972; Part II, concerning scattering by crystal surfaces, was published in 1974. Since the publication of these reviews the material contained in them has become obsolete in many respects. A more recent account of the status of the problem has been given in a number of studies, including the book by E.S. Mashkova and V.A. Molchanov, Medium-Energy Ion Scattering by Solid Surfaces (Atomizdat, Moscow, 1980), than extended version of which was published by North-Holland in 1985. We note, however, that at the time these reviews were written the study of fast recoil atoms had not been carried out systematically; the problem was studied only as a by-product of surface scattering and sputtering. For this reason, in the above-mentioned works and in other reviews the data relating to recoil atoms were considered only occasionally. In recent years there have appeared a number of works - theoretical, experimental and computer -specially devoted to the study of the ejection of recoil atoms under ion bombardment. A number of interesting effects, which are due to the crystal structure of the target, have been discovered. It therefore, appeared desirable to us to systematize the available material and to present it as Part III of our continuing review. (author)
Peculiarities of light ion-nucleus scattering in medium-energy region
International Nuclear Information System (INIS)
Berezhnoj, Yu.A.; Pilipenko, V.V.
1982-01-01
Differential cross-sections of 3 He and 4 He nuclei elastic scattering at E > or approximately 10 MeV/nucleon are analyzed in the quasi-classical approximation. At energies E > or approximately 25 MeV/nucleon in differential cross sections of 3 He and 4 He nuclei elastic scattering by atomic nuclei in the field of scattering angles THETA > or approximately 35 deg diffraction minima start to appear. ScuiSuch effect of Fraunhofer cross section oscillations is eluciiated on the basis of diffraction theory by means of modelfree determination of nuclear scattering phase and quantum deviation function. It is shown that the elastic scattering cross section in the field of energies under consideration represents a typical quasiclassical picture of ''iridescent'' scattering at strong absorption. The theoretical analysis performed permits to correctly describe the experimentally measured differential cross sections of 3 He nuclei elastic scattering at 109.2 MeV by 40 Ca, 58 Ni nuclei and at 118.5 NeV by 58 Ni nuclei as well as 4 He at 166 MeV by 24 Mg, 32 S and at 141.7 MeV by 40 Ca nuclei
International Nuclear Information System (INIS)
Yoshino, Hironori; Wada, Kenji; Horinaka, Hiromichi; Cho, Yoshio; Umeda, Tokuo; Osawa, Masahiko.
1995-01-01
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 -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)
In vivo diagnosis of skin cancer using polarized and multiple scattered light spectroscopy
Bartlett, Matthew Allen
This thesis research presents the development of a non-invasive diagnostic technique for distinguishing between skin cancer, moles, and normal skin using polarized and multiple scattered light spectroscopy. Polarized light incident on the skin is single scattered by the epidermal layer and multiple scattered by the dermal layer. The epidermal light maintains its initial polarization while the light from the dermal layer becomes randomized and multiple scattered. Mie theory was used to model the epidermal light as the scattering from the intercellular organelles. The dermal signal was modeled as the diffusion of light through a localized semi-homogeneous volume. These models were confirmed using skin phantom experiments, studied with in vitro cell cultures, and applied to human skin for in vivo testing. A CCD-based spectroscopy system was developed to perform all these experiments. The probe and the theory were tested on skin phantoms of latex spheres on top of a solid phantom. We next extended our phantom study to include in vitro cells on top of the solid phantom. Optical fluorescent microscope images revealed at least four distinct scatterers including mitochondria, nucleoli, nuclei, and cell membranes. Single scattering measurements on the mammalian cells consistently produced PSD's in the size range of the mitochondria. The clinical portion of the study consisted of in vivo measurements on cancer, mole, and normal skin spots. The clinical study combined the single scattering model from the phantom and in vitro cell studies with the diffusion model for multiple scattered light. When parameters from both layers were combined, we found that a sensitivity of 100% and 77% can be obtained for detecting cancers and moles, respectively, given the number of lesions examined.
Coherence effects and average multiplicity in deep inelastic scattering at small χ
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Kisselev, A.V.; Petrov, V.A.
1988-01-01
The average hadron multiplicity in deep inelastic scattering at small χ is calculated in this paper. Its relationship with the average multiplicity in e + e - annihilation is established. As shown the results do not depend on a choice of the gauge vector. The important role of coherence effects in both space-like and time-like jet evolution is clarified. (orig.)
Effective diffusion constant in a two-dimensional medium of charged point scatterers
International Nuclear Information System (INIS)
Dean, D S; Drummond, I T; Horgan, R R
2004-01-01
We obtain exact results for the effective diffusion constant of a two-dimensional Langevin tracer particle in the force field generated by charged point scatterers with quenched positions. We show that if the point scatterers have a screened Coulomb (Yukawa) potential and are uniformly and independently distributed then the effective diffusion constant obeys the Volgel-Fulcher-Tammann law where it vanishes. Exact results are also obtained for pure Coulomb scatterers frozen in an equilibrium configuration of the same temperature as that of the tracer
Neutron scattering in applied research: possibilities for medium-flux research reactors
International Nuclear Information System (INIS)
Reijonen, H.
1977-01-01
The possibilities for neutron scattering techniques in applied research are reviewed. The areas covered are magnetism, determination of hydrogen self-diffusion constants and ionic mobility in superionic conductors, liquid crystals, molecular solids, polymers, surface chemistry and catalysts, colloids biology, physical metallurgy and neutron diagnostics. Established applications and new proposals for research projects are presented in various degrees of detail. Small angle scattering techniques, physical metallurgy and biology were identified as having particular potential. Prospective users should be realistically informed of the possibilities of neutron scattering techniques. (author)
Scaling laws governing the multiple scattering of diatomic molecules under Coulomb explosion
International Nuclear Information System (INIS)
Sigmund, P.
1992-01-01
The trajectories of fast molecules during and after penetration through foils are governed by Coulomb explosion and distorted by multiple scattering and other penetration phenomena. A scattering event may cause the energy available for Coulomb explosion to increase or decrease, and angular momentum may be transferred to the molecule. Because of continuing Coulomb explosion inside and outside the target foil, the transmission pattern recorded at a detector far away from the target is not just a linear superposition of Coulomb explosion and multiple scattering. The velocity distribution of an initially monochromatic and well-collimated, but randomly oriented, beam of molecular ions is governed by a generalization of the standard Bothe-Landau integral that governs the multiple scattering of atomic ions. Emphasis has been laid on the distribution in relative velocity and, in particular, relative energy. The statistical distributions governing the longitudinal motion (i.e., the relative motion along the molecular axis) and the rotational motion can be scaled into standard multiple-scattering distributions of atomic ions. The two scaling laws are very different. For thin target foils, the significance of rotational energy transfer is enhanced by an order of magnitude compared to switched-off Coulomb explosion. A distribution for the total relative energy (i.e., longitudinal plus rotational motion) has also been found, but its scaling behavior is more complex. Explicit examples given for all three distributions refer to power-law scattering. As a first approximation, scattering events undergone by the two atoms in the molecule were assumed uncorrelated. A separate section has been devoted to an estimate of the effect of impact-parameter correlation on the multiple scattering of penetrating molecules
Broadband electromagnetic dipole scattering by coupled multiple nanospheres
Jing, Xufeng; Ye, Qiufeng; Hong, Zhi; Zhu, Dongshuo; Shi, Guohua
2017-11-01
With the development of nanotechnology, the ability to manipulate light at the nanoscale is critical to future optical functional devices. The use of high refractive index dielectric single silicon nanoparticle can achieve electromagnetic dipole resonant properties. Compared with single nanosphere, the use of dimer and trimer introduces an additional dimension (gap size) for improving the performance of dielectric optical devices through the coupling between closely connected silicon nanospheres. When changing the gap size between the nanospheres, the interaction between the particles can be from weak to strong. Compared with single nanospheres, dimerized or trimeric nanospheres exhibit more pronounced broadband scattering properties. In addition, by introducing more complex interaction, the trimericed silicon nanospheres exhibit a more significant increase in bandwidth than expected. In addition, the presence of the substrate will also contribute to the increase in the bandwidth of the nanospheres. The broadband response in dielectric nanostructures can be effectively applied to broadband applications such as dielectric nanoantennas or solar cells.
Application of the 2-D discrete-ordinates method to multiple scattering of laser radiation
International Nuclear Information System (INIS)
Zardecki, A.; Gerstl, S.A.W.; Embury, J.F.
1983-01-01
The discrete-ordinates finite-element radiation transport code twotran is applied to describe the multiple scattering of a laser beam from a reflecting target. For a model scenario involving a 99% relative humidity rural aerosol we compute the average intensity of the scattered radiation and correction factors to the Beer-Lambert law arising from multiple scattering. As our results indicate, 2-D x-y and r-z geometry modeling can reliably describe a realistic 3-D scenario. Specific results are presented for the two visual ranges of 1.52 and 0.76 km which show that, for sufficiently high aerosol concentrations (e.g., equivalent to V = 0.76 km), the target signature in a distant detector becomes dominated by multiply scattered radiation from interactions of the laser light with the aerosol environment. The merits of the scaling group and the delta-M approximation for the transfer equation are also explored
Effects of multiple scattering on radiative properties of soot fractal aggregates
International Nuclear Information System (INIS)
Yon, Jérôme; Liu, Fengshan; Bescond, Alexandre; Caumont-Prim, Chloé; Rozé, Claude; Ouf, François-Xavier; Coppalle, Alexis
2014-01-01
The in situ optical characterization of smokes composed of soot particles relies on light extinction, angular static light scattering (SLS), or laser induced incandescence (LII). These measurements are usually interpreted by using the Rayleigh–Debye–Gans theory for Fractal Aggregates (RDG-FA). RDG-FA is simple to use but it completely neglects the impact of multiple scattering (MS) within soot aggregates. In this paper, based on a scaling approach that takes into account MS effects, an extended form of the RDG-FA theory is proposed in order to take into account these effects. The parameters of this extended theory and their dependency on the number of primary sphere inside the aggregate (1 p <1006) and on the wavelength (266nm<λ<1064nm) are evaluated thanks to rigorous calculations based on discrete dipole approximation (DDA) and generalized multi-sphere Mie-solution (GMM) calculations. This study shows that size determination by SLS is not distorted by MS effect. On the contrary, it is shown that fractal dimension can be misinterpreted by light scattering experiments, especially at short wavelengths. MS effects should be taken into account for the interpretation of absorption measurements that are involved in LII or extinction measurements. -- Highlights: • We incorporate multiple scattering effects in a scaling approach for fractal aggregates. • A generalized structure factor is introduced for implementation in RDG-FA theory. • Forward scattering is affected by multiple scattering as well as power law regime. • Absorption cross sections are affected by multiple scattering. • Absorption cross sections are 11% higher than that for forward scattering
Multiple scattering expansion of the self-energy at finite temperature
International Nuclear Information System (INIS)
Jeon, S.; Ellis, P.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. copyright 1998 The American Physical Society
Multiple Scattering Expansion of the Self-Energy at Finite Temperature
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.
International Nuclear Information System (INIS)
Bret, Boris P. J.; Ferreira, Flavio P.; Nunes-Pereira, Eduardo J.; Belsley, Michael
2010-01-01
We report the decomposition of the enhanced backscattering cone into its constitutive interference fringes. These fringes are due to the constructive interference between reciprocal paths of any multiply scattered wave after ensemble averaging. An optical setup combining a two-point continuous-wave illumination and matching detection allows the observation of the fringes and, therefore, the quantitative characterization of the Green's function for light propagation between the two points in a multiple-scattering media.
International Nuclear Information System (INIS)
Cho, G.S.; Cho, B.H.
1981-01-01
As to the backscatter instability which is one of nonlinear three-wave resonant interactions, the reflectivity(r) in the case of homogeneous-slab medium is calculated, assuming all the three wavepackets negligible damping caused by medium. The expression has turned out such that r = tanh 2 KAsub(p)L, where K, Asub(p), and L are the constant coupling coefficient, the constant pump-wave amplitude, and the thickness of the medium engaged in the interaction each. When this result is interpreted in terms of the stimulated Brillouin back-scattering in a so-called underdense plasma in controlled fusion, we find the reflectivity twice as large as that by others in the limit of large pump-wave damping, and unfitting to former experiments in the independence on the incident laser-light intensity. We see the incompatibility rise chiefly from neglecting the damping of pump-wave in the plasma. In contrast to the former results by others in the limit of large pump-wave damping, our result might be regarded as that for cases of negligible pump-wave damping, in general stimulated back-scattering phenomena. (author)
Analytical calculations of multiple scattering for high energy photons and neutrons
International Nuclear Information System (INIS)
Thoe, R.S.
1994-04-01
Radiography of large dense objects often require the use of highly penetrating radiation. For example, a couple of centimeters of steel attenuates 50 keV x-rays by a factor of approximately 10 -14 whereas this same amount of steel would attenuate a 500 keV photon beam by only a factor of about 0.25. However, this increase in penetrating power comes with a price. In the case of x-radiation there are two bills to pay: (1) For projection radiography, this increase in penetration directly causes a corresponding decrease in resolution. (2) This increase in penetration occurs in a region where the interaction of radiation and matter is changing from absorption to scattering. In the above example the fraction of scattering goes from about 0.1 at 50 keV to over 0.99 at 500 keV. These scattered photons can significantly degrade contrast. In order to overcome some of these difficulties, radiography using scattered photons has been studied by myself and numerous other authors. In all the above cases, calculation of the intensity of scattered radiation is of primary importance. In cases where scattering is probable, multiple scattering can also be probable. Calculations of multiple scattering are generally very difficult and usually require the use of extremely sophisticated Monte Carlo simulations. It is not unusual for these calculations to require several hours of CPU time on some of the worlds largest and fastest supercomputers. In this paper I will present an alternative approach. I will present an analytical solution to the equations of double scattering, and show how this solution can extended to the case of higher order scattering. Finally, I will give numerical examples of these solutions and compare them to solutions obtained by Monte Carlo simulations
Multiple scattering of electromagnetic waves by a collection of plasma drift turbulent vortices
International Nuclear Information System (INIS)
Resendes, D.
1995-01-01
An application of the self-consistent multiple-scattering theory of electro-magnetic waves to drift turbulent vortices is presented. Using the known single-vortex solution, the integral equation describing the scattering from a finite density of drift turbulent vortices is obtained. Rather than solving this equation and then averaging, the averaging operation is taken first to obtain statistical moment equations, from which the coherent and incoherent scattering follow. These results are expressed in a Fourier basis, and the cross-section is evaluated. Limiting forms of the theory and straightforward generalizations are discussed. (Author)
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.
Two-dimensional phononic crystals with time-varying properties: a multiple scattering analysis
International Nuclear Information System (INIS)
Wright, D W; Cobbold, R S C
2010-01-01
Multiple scattering theory is a versatile two- and three-dimensional method for characterizing the acoustic wave transmission through many scatterers. It provides analytical solutions to wave propagation in scattering structures, and its computational complexity grows logarithmically with the number of scatterers. In this paper we show how the 2D method can be adapted to include the effects of time-varying material parameters. Specifically, a new T-matrix is defined to include the effects of frequency modulation that occurs in time-varying phononic crystals. Solutions were verified against finite difference time domain (FDTD) simulations and showed excellent agreement. This new method enables fast characterization of time-varying phononic crystals without the need to resort to lengthy FDTD simulations. Also, the method of combining T-matrices to form the T-supermatrix remains unchanged provided that the new matrix definitions are used. The method is quite compatible with existing implementations of multiple scattering theory and could be readily extended to three-dimensional multiple scattering theory
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.
Iqbal, N.; Choudhury, P. K.
2017-12-01
The paper deals with scattering of electromagnetic (EM) waves by perfectly magnetic conducting (PMC) cylinder coated with chiro-ferrite medium under the assumption of oblique angle of incidence wave with perpendicular polarization (transverse electric; TE). An on-demand (in respect of orientation) kind of conducting sheath helix structure is assumed to exist at the outer surface of cylinder. The effects of sheath helix orientation, along with the material parameters, such as chirality admittance and gyrotropy, on the echo width as well as the magnitude and phase of the electric and magnetic fields are investigated. Control on the anisotropic property remains greatly useful in obtaining the required optical response from the scatterer - the feature which would find fabulous sensing related applications.
MULTIPLE-PLANET SCATTERING AND THE ORIGIN OF HOT JUPITERS
International Nuclear Information System (INIS)
Beaugé, C.; Nesvorný, D.
2012-01-01
Doppler and transit observations of exoplanets show a pile-up of Jupiter-size planets in orbits with a 3 day period. A fraction of these hot Jupiters have retrograde orbits with respect to the parent star's rotation, as evidenced by the measurements of the Rossiter-McLaughlin effect. To explain these observations we performed a series of numerical integrations of planet scattering followed by the tidal circularization and migration of planets that evolved into highly eccentric orbits. We considered planetary systems having three and four planets initially placed in successive mean-motion resonances, although the angles were taken randomly to ensure orbital instability in short timescales. The simulations included the tidal and relativistic effects, and precession due to stellar oblateness. Our results show the formation of two distinct populations of hot Jupiters. The inner population (Population I) is characterized by semimajor axis a 1 Gyr and fits nicely the observed 3 day pile-up. A comparison between our three-planet and four-planet runs shows that the formation of hot Jupiters is more likely in systems with more initial planets. Due to the large-scale chaoticity that dominates the evolution, high eccentricities and/or high inclinations are generated mainly by close encounters between the planets and not by secular perturbations (Kozai or otherwise). The relative proportion of retrograde planets seems of be dependent on the stellar age. Both the distribution of almost aligned systems and the simulated 3 day pile-up also fit observations better in our four-planet simulations. This may suggest that the planetary systems with observed hot Jupiters were originally rich in the number of planets, some of which were ejected. In a broad perspective, our work therefore hints on an unexpected link between the hot Jupiters and recently discovered free floating planets.
Point spread function due to multiple scattering of light in the atmosphere
International Nuclear Information System (INIS)
Pękala, J.; Wilczyński, H.
2013-01-01
The atmospheric scattering of light has a significant influence on the results of optical observations of air showers. It causes attenuation of direct light from the shower, but also contributes a delayed signal to the observed light. The scattering of light therefore should be accounted for, both in simulations of air shower detection and reconstruction of observed events. In this work a Monte Carlo simulation of multiple scattering of light has been used to determine the contribution of the scattered light in observations of a point source of light. Results of the simulations and a parameterization of the angular distribution of the scattered light contribution to the observed signal (the point spread function) are presented. -- Author-Highlights: •Analysis of atmospheric scattering of light from an isotropic point source. •Different geometries and atmospheric conditions were investigated. •A parameterization of scattered light distribution has been developed. •The parameterization allows one to easily account for the light scattering in air. •The results will be useful in analyses of observations of extensive air shower
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.
Development of multiple scattering lidar to retrieve cloud extinction and size information
International Nuclear Information System (INIS)
Kim, Dukhyeon; Cheong, Hai Du; Kim, Young Gi; Park, Sun Ho
2008-01-01
Traditional Mie scattering cloud lidar have some limitations because of multiple scattering effects. Because this multiple scattering effects induce depolarization of spherical particle and enhancement of extinction coefficient. We cannot measure the phase of water with depolarization lidar, and also cannot measure the extinction coefficient with single FOV(Field Of View)Mie cloud lidar system. In the study, we have developed a multiple field of view Mie cloud liar system which can give many information about the cloud droplet such as cloud effective size, cloud number density, extinction coefficient of cloud, and phase of water through the correction of multiple scattering effects. For this purpose, we have developed a multiple field of view lidar system which composed of 32 different pinholes. Figure 1 shows the schematic diagram and picture of pinholes which start from 100μm to 8mm. Pihole is located at the focal plane of the parabolic mirror, in this case the minimum FOV is 67μrad, maximum FOV is 5.3 mrad. Figure 2 shows Monte Carlo simulation of the multiple scattering photons vs. cloud depth. In this calculation we assumed that wavelength normalized aerosol size(x)is 100, and density of cloud (extinction efficiency)is 0.01m"-1". By measuring FOV dependent signals and aerosol extinction coefficient we can extract effective droplet size through following equations. Here θ"d"is aerosol effective size, and z"j", f, Θ(z)are height, aerosol density dependent function, and angular size of lidar signal at the height z. Finally. f(z)depends on the light mean free path and number of scattering
Density model for medium range order in amorphous materials: application to small angle scattering
International Nuclear Information System (INIS)
Boucher, B.; Tournarie, M.; Chieux, P.; Convert, P.
1983-06-01
We consider a family of randomly spaced parallel planes, each plane dressed with a density function, h(x), where x is the distance from the plane. An expression for the volume scattering power from a system of N such families with random orientations in space is derived from Fourier transform of h(x), which can subsequently be determined from experimental observations. This density model is used to interpret the small angle neutron scattering (SANS) results for the amorphous alloy TbCusub(3.54)
International Nuclear Information System (INIS)
Peterson, G.A.; Hicks, R.S.
1985-09-01
The University of Massachusetts Medium Energy Nuclear Physics Group reports the status of its experimental and theoretical programs. An overview of projects in elastic and quasi-elastic electron scattering which have been completed in the past year is given. Projects which have been designed and which will soon be started are described as well. Descriptions of the theoretical models for nucleon-nucleon interactions, nuclear structure, electromagnetic interactions, and weak interactions are given as well. Listings of the literature of the group are given
International Nuclear Information System (INIS)
Mueller, D.W.; Crosbie, A.L.
2005-01-01
The topic of this work is the generalized X- and Y-functions of multidimensional radiative transfer. The physical problem considered is spatially varying, collimated radiation incident on the upper boundary of an isotropically scattering, plane-parallel medium. An integral transform is used to reduce the three-dimensional transport equation to a one-dimensional form, and a modified Ambarzumian's method is used to derive coupled, integro-differential equations for the source functions at the boundaries of the medium. The resulting equations are said to be in double-integral form because the integration is over both angular variables. Numerical results are presented to illustrate the computational characteristics of the formulation
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...
International Nuclear Information System (INIS)
Arneodo, M.; Ferrero, M.I.; Peroni, C.; Bee, C.P.; Bird, I.; Coughlan, J.; Sloan, T.; Braun, H.; Brueck, H.; Drees, J.; Edwards, A.; Krueger, J.; Montgomery, H.E.; Peschel, H.; Pietrzyk, U.; Poetsch, M.; Schneider, A.; Dreyer, T.; Ernst, T.; Haas, J.; Kabuss, E.M.; Landgraf, U.; Mohr, W.; Rith, K.; Schlagboehmer, A.; Schroeder, T.; Stier, H.E.; Wallucks, W.
1987-01-01
The multiplicity distributions of charged hadrons produced in the deep inelastic muon-proton scattering at 280 GeV are analysed in various rapidity intervals, as a function of the total hadronic centre of mass energy W ranging from 4-20 GeV. Multiplicity distributions for the backward and forward hemispheres are also analysed separately. The data can be well parameterized by binomial distributions, extending their range of applicability to the case of lepton-proton scattering. The energy and the rapidity dependence of the parameters is presented and a smooth transition from the binomial distribution via Poissonian to the ordinary binomial is observed. (orig.)
Yura, H T; Thrane, L; Andersen, P E
2000-12-01
Within the paraxial approximation, a closed-form solution for the Wigner phase-space distribution function is derived for diffuse reflection and small-angle scattering in a random medium. This solution is based on the extended Huygens-Fresnel principle for the optical field, which is widely used in studies of wave propagation through random media. The results are general in that they apply to both an arbitrary small-angle volume scattering function, and arbitrary (real) ABCD optical systems. Furthermore, they are valid in both the single- and multiple-scattering regimes. Some general features of the Wigner phase-space distribution function are discussed, and analytic results are obtained for various types of scattering functions in the asymptotic limit s > 1, where s is the optical depth. In particular, explicit results are presented for optical coherence tomography (OCT) systems. On this basis, a novel way of creating OCT images based on measurements of the momentum width of the Wigner phase-space distribution is suggested, and the advantage over conventional OCT images is discussed. Because all previous published studies regarding the Wigner function are carried out in the transmission geometry, it is important to note that the extended Huygens-Fresnel principle and the ABCD matrix formalism may be used successfully to describe this geometry (within the paraxial approximation). Therefore for completeness we present in an appendix the general closed-form solution for the Wigner phase-space distribution function in ABCD paraxial optical systems for direct propagation through random media, and in a second appendix absorption effects are included.
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
A Two-Dimensional Helmholtz Equation Solution for the Multiple Cavity Scattering Problem
2013-02-01
obtained by using the block Gauss – Seidel iterative meth- od. To show the convergence of the iterative method, we define the error between two...models to the general multiple cavity setting. Numerical examples indicate that the convergence of the Gauss – Seidel iterative method depends on the...variational approach. A block Gauss – Seidel iterative method is introduced to solve the cou- pled system of the multiple cavity scattering problem, where
Mishchenko, Michael I.; Yang, Ping
2018-01-01
In this paper we make practical use of the recently developed first-principles approach to electromagnetic scattering by particles immersed in an unbounded absorbing host medium. Specifically, we introduce an actual computational tool for the calculation of pertinent far-field optical observables in the context of the classical Lorenzâ€"Mie theory. The paper summarizes the relevant theoretical formalism, explains various aspects of the corresponding numerical algorithm, specifies the input and output parameters of a FORTRAN program available at https://www.giss.nasa.gov/staff/mmishchenko/Lorenz-Mie.html, and tabulates benchmark results useful for testing purposes. This public-domain FORTRAN program enables one to solve the following two important problems: (i) simulate theoretically the reading of a remote well-collimated radiometer measuring electromagnetic scattering by an individual spherical particle or a small random group of spherical particles; and (ii) compute the single-scattering parameters that enter the vector radiative transfer equation derived directly from the Maxwell equations.
Mishchenko, Michael I.; Yang, Ping
2018-01-01
In this paper we make practical use of the recently developed first-principles approach to electromagnetic scattering by particles immersed in an unbounded absorbing host medium. Specifically, we introduce an actual computational tool for the calculation of pertinent far-field optical observables in the context of the classical Lorenz-Mie theory. The paper summarizes the relevant theoretical formalism, explains various aspects of the corresponding numerical algorithm, specifies the input and output parameters of a FORTRAN program available at https://www.giss.nasa.gov/staff/mmishchenko/Lorenz-Mie.html, and tabulates benchmark results useful for testing purposes. This public-domain FORTRAN program enables one to solve the following two important problems: (i) simulate theoretically the reading of a remote well-collimated radiometer measuring electromagnetic scattering by an individual spherical particle or a small random group of spherical particles; and (ii) compute the single-scattering parameters that enter the vector radiative transfer equation derived directly from the Maxwell equations.
Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target
Czech Academy of Sciences Publication Activity Database
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.; Badelek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bodlák, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Capozza, L.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, A.; Chung, S. U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; 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 jr., M.; Fischer, H.; Franco, C.; 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-Perdekapm, 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.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jarý, V.; Joosten, R.; Jörg, P.; Kabuss, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; 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.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, R.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; 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.; Rybnikov, A.; Rychter, A.; Salač, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, H.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolík, J.; Sozzi, F.; Srnka, Aleš; 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.; Závada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Zink, A.
2017-01-01
Roč. 767, 10 APRIL (2017), s. 133-141 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : deep inelastic scattering * kaon multiplicities * quark fragmentation functions * strange quark Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Nuclear physics Impact factor: 4.807, year: 2016
Coulomb correction to the screening angle of the Moliere multiple scattering theory
International Nuclear Information System (INIS)
Kuraev, E.A.; Voskresenskaya, O.O.; 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 4 ≤ Z ≤ 82. Comparison with the Moliere result for the screening angle reveals up to 30% deviation from it for sufficiently heavy elements of the target material
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.
Multiple scattering in electron fluid and energy loss in multi-ionic targets
International Nuclear Information System (INIS)
Deutsch, C.; Tahir, N.A.; Barriga-Carrasco, M.; Ceban, V.; Fromy, P.; Gilles, D.; Leger, D.; Maynard, G.; Tashev, B.; Volpe, L.
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 method for the generation of random multiple Coulomb scattering angles
International Nuclear Information System (INIS)
Campbell, J.R.
1995-06-01
A method for the random generation of spatial angles drawn from non-Gaussian multiple Coulomb scattering distributions is presented. The method employs direct numerical inversion of cumulative probability distributions computed from the universal non-Gaussian angular distributions of Marion and Zimmerman. (author). 12 refs., 3 figs
Multiple scattering corrections to the Beer-Lambert law. 2: Detector with a variable field of view.
Zardecki, A; Tam, W G
1982-07-01
The multiple scattering corrections to the Beer-Lambert law in the case of a detector with a variable field of view are analyzed. We introduce transmission functions relating the received radiant power to reference power levels relevant to two different experimental situations. In the first case, the transmission function relates the received power to a reference power level appropriate to a nonattenuating medium. In the second case, the reference power level is established by bringing the receiver to the close-up position with respect to the source. To examine the effect of the variation of the detector field of view the behavior of the gain factor is studied. Numerical results modeling the laser beam propagation in fog, cloud, and rain are presented.
Jain, Neha; Shukla, Prashant; Singh, Jai
2018-05-01
Correlation images are very useful in determining the morphological changes. We have investigated the correlation image analysis on depolarization and retardance matrices of polystyrene and gelatine samples respectively. We observed that that correlation images have a potential to show a significant variation with change in the concentration of samples (polystyrene and gelatine). For polystyrene microspheres the correlation value decreases with increasing scattering coefficient. In gelatine samples the correlation also decreases with sample concentration. This variation in correlation for retardance shows the change in a birefringence property of gelatine solution.
Polarization of recoil deuteron in ed elastic scattering at medium energies
International Nuclear Information System (INIS)
Bhalerao, R. S.
1981-12-01
Vector and tensor polarizations of the recoil deuteron in ed elastic scattering are calculated for THETA=0deg-180deg and q 2 2 . A longitudinally polarized electron beam is assumed to scatter off an unpolarized deuteron target. Calculations are made in the relativistic impulse approximation using a recently described approach based on the Bethe-Salpeter equation. Results are different, at high q 2 even qualitatively so, from those of a non-relativistic calculation, and a relativistic calculation which takes the spectator nucleon on-mass-shell. In the light of these results a recent suggestion that the polarization measurements would throw new light on the off-shell behavior and tensor force strength of the NN interaction are reexamined. Results are also presented for the three deuteron form factors Gsub(C), Gsub(Q), and Gsub(M), and the often-needed related quantities Ssub(S), Ssub(Q), and Ssub(M). The latter results may have an important implication in high-momentum transfer reactions involving deuteron. (author)
Experimental parameters for quantitative surface analysis by medium energy ion scattering, ch. 1
International Nuclear Information System (INIS)
Turkenburg, W.C.; Kersten, H.H.; Colenbrander, B.G.; Jongh, A.P. de; Saris, F.W.
1976-01-01
A new UHV chamber for surface and surface layer analysis by collision spectroscopy of backscattered ions at medium energies is described. Experimental parameters like energy, angular and depth resolution, crystal alignment and background pressure are discussed. Formulae based on the use of an electrostatic energy analyser show that the analysis can be quantitative. Effects of beam induced build-up of a hydro-carbon layer, sputter cleaning and creation of radiation damage have been investigated for Cu (110) and Ni (110). Detection sensitivity for Carbon, Oxygen and Sulfur on Cu and Ni has been found to be 0.2, 0.1 and 0.03 of a monolayer respectively
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...
A T-matrix calculation for in-medium heavy-quark gluon scattering
International Nuclear Information System (INIS)
Huggins, K.; Rapp, R.
2012-01-01
The interactions of charm and bottom quarks in a quark-gluon plasma (QGP) are evaluated using a thermodynamic 2-body T-matrix. We specifically focus on heavy-quark (HQ) interactions with thermal gluons with an input potential motivated by lattice-QCD computations of the HQ free energy. The latter is implemented into a field-theoretic ansatz for color-Coulomb and (remnants of) confining interactions. This, in particular, enables to discuss corrections to the potential approach, specifically hard-thermal-loop corrections to the vertices, relativistic corrections deduced from pertinent Feynman diagrams, and a suitable projection on transverse thermal gluons. The resulting potentials are applied to compute scattering amplitudes in different color channels and utilized for a calculation of the corresponding HQ drag coefficient in the QGP. A factor of ∼2-3 enhancement over perturbative results is obtained, mainly driven by the resummation in the attractive color-channels.
Energy Technology Data Exchange (ETDEWEB)
Crut, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1960-07-01
The aim of this work is to find out what are the properties of the so-called 'anomalous states' in medium weight nuclei. These states preferentially excited in the inelastic scattering of medium energy charged particles have an excitation energy at about 4 MeV for nuclei with Z {<=} 29 and in the range 2-3 MeV for high Z nuclei. From a combination of angular distribution data in the elastic and inelastic scattering of 30 MeV {alpha} particles, and correlation data between inelastic {alpha} particles and deexcitation {gamma} rays, we show that for even-even nuclei, we can attribute spin 3 and parity minus to these 'anomalous states'. This is quite in agreement with the interpretation of these levels suggested by Lane as due to collective octupole oscillations. We give a resume of the theories used in the analysis of the data and a description of the experimental set-up. (author) [French] Le but de cette etude est de determiner les proprietes des niveaux dits 'anormalement excites' lors de la diffusion inelastique des particules chargees de moyenne energie sur des noyaux de masse moyenne et lourde. L'energie de ces niveaux est de l'ordre de 4 MeV pour les noyaux avec Z {<=} 29 et de 2 a 3 MeV pour les noyaux de Z plus eleve. De l'examen des courbes de distribution angulaire des particules {alpha} de 30 MeV diffusees elastiquement et inelastiquement, et de la correlation angulaire entre {alpha} excitant ces niveaux 'anormaux' et {gamma} de desexcitation, on deduit que, dans le cas des pair-pair, on peut attribuer a ces niveaux spin 3 et parite moins. Ceci renforce l'hypothese emise par Lane qui attribue ces niveaux a des oscillations octupolaires de la surface du noyau. On donne un apercu des theories utilisees dans l'analyse des resultats et une description des dispositifs experimentaux. (auteur)
Lee, Jung; Yoon, Jung-Hwan; Lee, Jae Young; Kim, Se Hyung; Lee, Jeong Eun; Han, Joon Koo; Choi, Byung Ihn
2012-01-01
Objective To prospectively evaluate the safety and short-term therapeutic efficacy of switching monopolar radiofrequency ablation (RFA) with multiple electrodes to treat medium-sized (3.1-5.0 cm), hepatocellular carcinomas (HCC). Materials and Methods In this prospective study, 30 patients with single medium-sized HCCs (mean, 3.5 cm; range, 3.1-4.4 cm) were enrolled. The patients were treated under ultrasonographic guidance by percutaneous switching monopolar RFA with a multichannel RF generator and two or three internally cooled electrodes. Contrast-enhanced CT scans were obtained immediately after RFA, and the diameters and volume of the ablation zones were then measured. Follow-up CT scans were performed at the first month after ablation and every three months thereafter. Technical effectiveness, local progression and remote recurrence of HCCs were determined. Results There were no major immediate or periprocedural complications. However, there was one bile duct stricture during the follow-up period. Technical effectiveness was achieved in 29 of 30 patients (97%). The total ablation time of the procedures was 25.4 ± 8.9 minutes. The mean ablation volume was 73.8 ± 56.4 cm3 and the minimum diameter was 4.1 ± 7.3 cm. During the follow-up period (mean, 12.5 months), local tumor progression occurred in three of 29 patients (10%) with technical effectiveness, while new HCCs were detected in six of 29 patients (21%). Conclusion Switching monopolar RFA with multiple electrodes in order to achieve a sufficient ablation volume is safe and efficient. This method also showed relatively successful therapeutic effectiveness on short-term follow up for the treatment of medium-sized HCCs. PMID:22247634
Pinheiro, F A; Martínez, A S
2001-01-01
We review some of our recent results concerning the single and multiple electromagnetic scattering by magnetic spherical particles. For a single electromagnetic scattering we show that the magnetic contribution alters, when compared to nonmagnetic scattering, the behavior of the cross sections and mean cosine of the scattering angle (cos omega). For ferromagnetic particles, resonances may occur even in the small-particle limit when the particle radius is much smaller than the wavelength. The resonances increase the cross sections while (cos omega) is diminished , and even may become negative. Several quantities such the Ioffe-Regel parameter for localization are calculated for the multiple scattering regime. We show that magnetic scattering favors the observation of localization of electromagnetic waves in three dimensions. Further, this is also verified for dynamical experiments, where we show that the diffusion constant can be very small. Since the magnetic permeability of the scatterers can vary significan...
International Nuclear Information System (INIS)
Singh, Gurvinderjit; Singh, Manpreet; Sandhu, B.S.; Singh, Bhajan
2008-01-01
The energy, intensity and angular distributions of multiple scattering of 662 keV gamma photons, emerging from targets of pure elements and binary alloys, are observed as a function of target thickness in reflection and transmission geometries. The observed spectra recorded by a properly shielded NaI (Tl) scintillation detector, in addition to singly scattered events, consist of photons scattered more than once for thick targets. To extract the contribution of multiply scattered photons from the measured spectra, a singly scattered distribution is reconstructed analytically. We observe that the numbers of multiply scattered events increase with increase in target thickness, and saturate for a particular thickness called saturation thickness. The saturation thickness decreases with increasing atomic number. The multiple scattering, an interfering background noise in Compton profiles and Compton cross-section measurements, has been successfully used as a new technique to assign the 'effective atomic number' to binary alloys. Monte Carlo calculations support the present experimental results
Barnett, Alex H.; Nelson, Bradley J.; Mahoney, J. Matthew
2015-09-01
We apply boundary integral equations for the first time to the two-dimensional scattering of time-harmonic waves from a smooth obstacle embedded in a continuously-graded unbounded medium. In the case we solve, the square of the wavenumber (refractive index) varies linearly in one coordinate, i.e. (Δ + E +x2) u (x1 ,x2) = 0 where E is a constant; this models quantum particles of fixed energy in a uniform gravitational field, and has broader applications to stratified media in acoustics, optics and seismology. We evaluate the fundamental solution efficiently with exponential accuracy via numerical saddle-point integration, using the truncated trapezoid rule with typically 102 nodes, with an effort that is independent of the frequency parameter E. By combining with a high-order Nyström quadrature, we are able to solve the scattering from obstacles 50 wavelengths across to 11 digits of accuracy in under a minute on a desktop or laptop.
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.
Multiple scattering of low energy rare gas ions: a comparison of experiment and computer simulation
International Nuclear Information System (INIS)
Heiland, W.; Taglauer, E.; Robinson, M.T.
1976-01-01
Some aspects of ion scattering below a few keV have been interpreted by multiple scattering. This can partly be simulated by chain or string models, where the single crystal surface is replaced by a chain of atoms. The computer program MARLOWE allows a simulation of solid-ion interaction, which is much closer to reality, e.g. the crystal is three-dimensional, includes lattice vibrations, electronic stopping power, different scattering potentials, etc. It is shown that the energy of the reflected ions as a function of the primary energy, lattice constant, impact angle and scattering angle can be understood within the string model. These results of the string model are confirmed by the MARLOWE calculations. For an interpretation of the measured intensities the simple string model is insufficient, whereas with MARLOWE reasonable agreement with experimental data may be achieved, if the thermal vibrations of the lattice atoms are taken into account. The experimental data include Ne + →Ni, Ne + →Ag and preliminary data on Ne + →W. The screening parameters of the scattering potentials are estimated for these ion-atom combinations. The results allow some conclusions about surface Debye temperatures. (Auth.)
International Nuclear Information System (INIS)
Kato, Hideki; Sakai, Keita; Uchiyama, Mizuki; Suzuki, Kentaro
2016-01-01
The diagnostic reference levels (DRLs) of the general X-ray radiography are defined by the absorbed dose of air at the entrance surface with backscattered radiation from a scattering medium. Generally, the entrance surface dose of the general X-ray radiography is calculated from measured air kerma of primary X-ray multiplied by a backscatter factor (BSF). However, the BSF data employed at present used water for scattering medium, and was calculated based on the water-absorbed dose by incident primary photons and backscattered photons from the scattering medium. In the calculation of air dose at the entrance surface defined in DRLs, there are no theoretical consistencies for using BSF based on water dose, and this may be a cause of calculation error. In this paper, we verified the difference in BSF by the difference in the scattering medium and by the difference in the objective dose by means of the Monte Carlo simulation. In this calculation, the scattering medium was set as water and the soft-tissue, and the objective dose was set as air dose, water dose, soft-tissue dose, and skin dose. The difference in BSF calculated by the respective combination was at most about 1.3% and was less than 1% in most cases. In conclusion, even if the entrance surface dose defined by DRLs of general X-ray radiography is calculated using BSF, which set both the scattering medium and the object substance of the absorbed dose as water, a so big error doesn't show. (author)
International Nuclear Information System (INIS)
Kawrakow, I.; Bielajew, A.F.
1998-01-01
A new representation of elastic electron-nucleus (Coulomb) multiple-scattering distributions is developed. Using the screened Rutherford cross section with the Moliere screening parameter as an example, a simple analytic angular transformation of the Goudsmit-Saunderson multiple-scattering distribution accounts for most of the structure of the angular distribution leaving a residual 3-parameter (path-length, transformed angle and screening parameter) function that is reasonably slowly varying and suitable for rapid, accurate interpolation in a computer-intensive algorithm. The residual function is calculated numerically for a wide range of Moliere screening parameters and path-lengths suitable for use in a general-purpose condensed-history Monte Carlo code. Additionally, techniques are developed that allow the distributions to be scaled to account for energy loss. This new representation allows ''''on-the-fly'''' sampling of Goudsmit-Saunderson angular distributions in a screened Rutherford approximation suitable for class II condensed-history Monte Carlo codes. (orig.)
Qiu, Xiang; Dai, Ming; Yin, Chuan-li
2017-09-01
Unmanned aerial vehicle (UAV) remote imaging is affected by the bad weather, and the obtained images have the disadvantages of low contrast, complex texture and blurring. In this paper, we propose a blind deconvolution model based on multiple scattering atmosphere point spread function (APSF) estimation to recovery the remote sensing image. According to Narasimhan analytical theory, a new multiple scattering restoration model is established based on the improved dichromatic model. Then using the L0 norm sparse priors of gradient and dark channel to estimate APSF blur kernel, the fast Fourier transform is used to recover the original clear image by Wiener filtering. By comparing with other state-of-the-art methods, the proposed method can correctly estimate blur kernel, effectively remove the atmospheric degradation phenomena, preserve image detail information and increase the quality evaluation indexes.
Smith, James A.
1992-01-01
The inversion of the leaf area index (LAI) canopy parameter from optical spectral reflectance measurements is obtained using a backpropagation artificial neural network trained using input-output pairs generated by a multiple scattering reflectance model. The problem of LAI estimation over sparse canopies (LAI 1000 percent for low LAI. Minimization methods applied to merit functions constructed from differences between measured reflectances and predicted reflectances using multiple-scattering models are unacceptably sensitive to a good initial guess for the desired parameter. In contrast, the neural network reported generally yields absolute percentage errors of <30 percent when weighting coefficients trained on one soil type were applied to predicted canopy reflectance at a different soil background.
Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target
Adolph, C.
2017-04-10
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.
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.
Ben-David, Avishai
1992-01-01
Knowing the optical properties of aerosol dust is important for designing electro-optical systems and for modeling the effect on propagation of light in the atmosphere. As CO2 lidar technology becomes more advanced and is used for multiwavelength measurements, information on the wavelength dependent backscattering of aerosol dust particles is required. The volume backscattering coefficient of aerosols in the IR is relatively small. Thus, only a few field measurements of backscattering, usually at only a few wavelengths, are reported in the literature. We present spectral field measurements of backscattering of kaolin dust in the 9-11 micron wavelength range. As the quantity of dust increases, multiple scattering contributes more to the measured backscattered signal. The measurements show the effect of the dust quantity of the spectral backscatter measurements. A simple analytical two stream radiative transfer model is applied to confirm the measurements and to give insight to the multiple scattering spectra of backscattering.
Atmospheric neutrino oscillations from upward throughgoing muon multiple scattering in MACRO
Energy Technology Data Exchange (ETDEWEB)
Ambrosio, M.; Antolini, R.; 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.; 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.; 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.; Iarocci, E.; 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.; Monacelli, P.; Montaruli, T.; Monteno, M.; Mufson, S.; Musser, J.; Nicolo, D.; Nolty, R.; Orth, C.; Osteria, G.; Palamara, O.; Patera, V.; Patrizii, L.; Pazzi, R.; Peck, C.W.; Perrone, L.; Petrera, S.; Popa, V.; Raino, 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
2003-07-24
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.
All orders Boltzmann collision term from the multiple scattering expansion of the self-energy
International Nuclear Information System (INIS)
Fillion-Gourdeau, F.; Gagnon, J.-S.; Jeon, S.
2007-01-01
We summarize our main findings in deriving the Boltzmann collision term from the Kadanoff-Baym relativistic transport equation and the multiple scattering expansion of the self-energy within a quasi-particle approximation. Our collision term is valid to all orders in perturbation theory and contains processes with any number of participating particles. This work completes a program initiated by Carrington and Mrowczynski and developed further by present authors and Weinstock in recent literature
Exploitation of Microdoppler and Multiple Scattering Phenomena for Radar Target Recognition
2006-08-24
progress on the reserach grant "Exploitation of MicroDoppler and Multiple Scattering Phenomena for Radar Target Recognition" during the period 1...paper describes a methodology of modeling A number of ray-based EM techniques have been interferometric synthetic aperture radar (IFSAR) images...modes including the single present an IFSAR simulation methodology to simulate the antenna transmit mode, the ping-pong mode or the repeat interferogram
Quantum theory of dynamic multiple light scattering in fluctuating disordered media
International Nuclear Information System (INIS)
Skipetrov, S. E.
2007-01-01
We formulate a quantum theory of dynamic multiple light scattering in fluctuating disordered media and calculate the fluctuation and the autocorrelation function of the photon number operator for light transmitted through a disordered slab. The effect of disorder on the information capacity of a quantum communication channel operating in a disordered environment is estimated, and the use of squeezed light in diffusing-wave spectroscopy is discussed
International Nuclear Information System (INIS)
Broome, J.
1965-11-01
The programme SCATTER is a KDF9 programme in the Egtran dialect of Fortran to generate normalized angular distributions for elastically scattered neutrons from data input as the coefficients of a Legendre polynomial series, or from differential cross-section data. Also, differential cross-section data may be analysed to produce Legendre polynomial coefficients. Output on cards punched in the format of the U.K. A. E. A. Nuclear Data Library is optional. (author)
Multiple scattering theory and applications for intermediate energy reactions of nuclei
International Nuclear Information System (INIS)
Ludeking, L.D.
1979-01-01
Interactions of two composite clusters are treated in a multiple scattering framework whereby many-particle operators are decomposed into a systematic and finite series such that there is an ordered sequestering according to particle rank. Thus, an N-body operator is written as the superposition of all distinct groupings of interactions that occur between particle pairs, triplets, quartets, etc., such that all groupings contain at least one particle from each of the composite systems. It is demonstrated how the transition operator, a reaction operator, and an optical potential may be described in this context. The general structure of such decompositions is shown, and the connection to the standard multiple-scattering prescriptions, delineated. The direct reaction amplitude for stripping and pickup is described, and the two potential formula of Gell-Mann and Goldberger is derived. The multiple scattering formalism for direct reactions is constructed in the eikonal approximation. The sensitivity of the transition cross section to the target density and nucleon-nucleon density correlations are examined in this framework. The limitations of the zero-range approximation to the deuteron vertex function are examined by comparison with the finite-range vertex function at a range of energies. 25 figures, 5 tables
Directory of Open Access Journals (Sweden)
Wasaye Muhammad Abdul
2017-01-01
Full Text Available An algorithm for the Monte Carlo simulation of electron multiple elastic scattering based on the framework of SuperMC (Super Monte Carlo simulation program for nuclear and radiation process is presented. This paper describes efficient and accurate methods by which the multiple scattering angular deflections are sampled. The Goudsmit-Saunderson theory of multiple scattering has been used for sampling angular deflections. Differential cross-sections of electrons and positrons by neutral atoms have been calculated by using Dirac partial wave program ELSEPA. The Legendre coefficients are accurately computed by using the Gauss-Legendre integration method. Finally, a novel hybrid method for sampling angular distribution has been developed. The model uses efficient rejection sampling method for low energy electrons (500 mean free paths. For small path lengths, a simple, efficient and accurate analytical distribution function has been proposed. The later uses adjustable parameters determined from the fitting of Goudsmith-Saunderson angular distribution. A discussion of the sampling efficiency and accuracy of this newly developed algorithm is given. The efficiency of rejection sampling algorithm is at least 50 % for electron kinetic energies less than 500 keV and longer path lengths (>500 mean free paths. Monte Carlo Simulation results are then compared with measured angular distributions of Ross et al. The comparison shows that our results are in good agreement with experimental measurements.
Correlations in multiple production on nuclei and Glauber model of multiple scattering
International Nuclear Information System (INIS)
Zoller, V.R.; Nikolaev, N.N.
1982-01-01
Critical analysis of possibility for describing correlation phenomena during multiple production on nuclei within the framework of the Glauber multiple seattering model generalized for particle production processes with Capella, Krziwinski and Shabelsky has been performed. It was mainly concluded that the suggested generalization of the Glauber model gives dependences on Ng(Np) (where Ng-the number of ''grey'' tracess, and Np-the number of protons flying out of nucleus) and, eventually, on #betta# (where #betta#-the number of intranuclear interactions) contradicting experience. Independent of choice of relation between #betta# and Ng(Np) in the model the rapidity corrletor Rsub(eta) is overstated in the central region and understated in the region of nucleus fragmentation. In mean multiplicities these two contradictions of experience are disguised with random compensation and agreement with experience in Nsub(S) (function of Ng) cannot be an argument in favour of the model. It is concluded that eiconal model doesn't permit to quantitatively describe correlation phenomena during the multiple production on nuclei
Dual wavelength multiple-angle light scattering system for cryptosporidium detection
Buaprathoom, S.; Pedley, S.; Sweeney, S. J.
2012-06-01
A simple, dual wavelength, multiple-angle, light scattering system has been developed for detecting cryptosporidium suspended in water. Cryptosporidium is a coccidial protozoan parasite causing cryptosporidiosis; a diarrheal disease of varying severity. The parasite is transmitted by ingestion of contaminated water, particularly drinking-water, but also accidental ingestion of bathing-water, including swimming pools. It is therefore important to be able to detect these parasites quickly, so that remedial action can be taken to reduce the risk of infection. The proposed system combines multiple-angle scattering detection of a single and two wavelengths, to collect relative wavelength angle-resolved scattering phase functions from tested suspension, and multivariate data analysis techniques to obtain characterizing information of samples under investigation. The system was designed to be simple, portable and inexpensive. It employs two diode lasers (violet InGaN-based and red AlGaInP-based) as light sources and silicon photodiodes as detectors and optical components, all of which are readily available. The measured scattering patterns using the dual wavelength system showed that the relative wavelength angle-resolved scattering pattern of cryptosporidium oocysts was significantly different from other particles (e.g. polystyrene latex sphere, E.coli). The single wavelength set up was applied for cryptosporidium oocysts'size and relative refractive index measurement and differential measurement of the concentration of cryptosporidium oocysts suspended in water and mixed polystyrene latex sphere suspension. The measurement results showed good agreement with the control reference values. These results indicate that the proposed method could potentially be applied to online detection in a water quality control system.
High amplitude ultrasound pulse generation using time-reversal through a multiple scattering medium
ARNAL , Bastien; Pernot , Mathieu; Fink , Mathias; Tanter , Mickaël
2012-01-01
International audience; In histotripsy, soft tissues can be fragmented using very high pressure ultrasound pulses. Using time-reversal cavity is a way to generate high pressure pulses with a limited number of acoustic sources. The principle was already demonstrated by Montaldo et al. using a solid metal cavity, but low transmission coefficient was obtained due to the strong impedance mismatch at the metal/water interface. We propose here to use a waveguide filled with water containing a 2D mu...
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
Mass hierarchy sensitivity of medium baseline reactor neutrino experiments with multiple detectors
Directory of Open Access Journals (Sweden)
Hong-Xin Wang
2017-05-01
Full Text Available 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.
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.
Frequency stabilization of multiple lasers on a single medium-finesse cavity
Han, Chengyin; Zhou, Min; Gao, Qi; Li, Shangyan; Zhang, Shuang; Qiao, Hao; Ai, Di; Zhang, Mengya; Lou, Ge; Luo, Limeng; Xu, Xinye
2018-04-01
We present a simple, compact, and robust frequency stabilization system of three lasers operating at 649, 759, and 770 nm, respectively. These lasers are applied in experiments on ytterbium optical lattice clocks, for which each laser needs to have a linewidth of a few hundred or tens of kilohertz while maintaining a favorable long-term stability. Here, a single medium-finesse cavity is adopted as the frequency reference and the standard Pound-Drever-Hall technique is used to stabilize the laser frequencies. Based on the independent phase modulation, multiple-laser locking is demonstrated without mutual intervention. The locked lasers are measured to have a linewidth of 100 kHz and the residual frequency drift is about 78.5 Hz s-1. This kind of setup provides a construction that is much simpler than that in previous work.
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......, it is more complex to control and manage. Thus in order to maintain the frequency stability in multiple-time-scales, a hierarchical control strategy is proposed. The proposed control architecture divides the system frequency in three zones: (A) stable zone, (B) precautionary zone and (C) emergency zone...... 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....
International Nuclear Information System (INIS)
Tornow, W.; Mertens, G.
1977-01-01
In order to study multiple scattering effects both in the gas and particularly in the solid materials of high-pressure gas scintillators, two asymmetry experiments have been performed by scattering of 15.6 MeV polarized neutrons from helium contained in stainless steel vessels of different wall thicknesses. A monte Carlo computer code taking into account the polarization dependence of the differential scattering cross sections has been written to simulate the experiments and to calculate corrections for multiple scattering on helium, xenon and the gas containment materials. Besides the asymmetries for the various scattering processes involved, the code yields time-of-flight spectra of the scattered neutrons and pulse height spectra of the helium recoil nuclei in the gas scintillator. The agreement between experimental results and Monte Carlo calculations is satisfactory. (Auth.)
International Nuclear Information System (INIS)
Dehmer, J.L.; Dill, D.
1974-01-01
A prototype calculation of the well-known 2.5-eV shape resonance in e-N 2 scattering was performed to test the usefulness of the multiple-scattering method for electronic continuum molecular wavefunctions. The results of this demanding test are very encouraging. (U.S.)
Schultz, E.; Genuer, V.; Marcoux, P.; Gal, O.; Belafdil, C.; Decq, D.; Maurin, Max; Morales, S.
2018-02-01
Elastic Light Scattering (ELS) is an innovative technique to identify bacterial pathogens directly on culture plates. Compelling results have already been reported for agri-food applications. Here, we have developed ELS for clinical diagnosis, starting with Staphylococcus aureus early screening. Our goal is to bring a result (positive/negative) after only 6 h of growth to fight surgical-site infections. The method starts with the acquisition of the scattering pattern arising from the interaction between a laser beam and a single bacterial colony growing on a culture medium. Then, the resulting image, considered as the bacterial species signature, is analyzed using statistical learning techniques. We present a custom optical setup able to target bacterial colonies with various sizes (30-500 microns). This system was used to collect a reference dataset of 38 strains of S. aureus and other Staphyloccocus species (5459 images) on ChromIDSAID/ MRSA bi-plates. A validation set from 20 patients has then been acquired and clinically-validated according to chromogenic enzymatic tests. The best correct-identification rate between S. aureus and S. non-aureus (94.7%) has been obtained using a support vector machine classifier trained on a combination of Fourier-Bessel moments and Local- Binary-Patterns extracted features. This statistical model applied to the validation set provided a sensitivity and a specificity of 90.0% and 56.9%, or alternatively, a positive predictive value of 47% and a negative predictive value of 93%. From a clinical point of view, the results head in the right direction and pave the way toward the WHO's requirements for rapid, low-cost, and automated diagnosis tools.
Characterisation of ultrasonic structural noise in multiple scattering media using phased arrays
International Nuclear Information System (INIS)
Bedetti, T; Dorval, V; Jenson, F; Derode, A
2013-01-01
The ultrasonic inspection of multiple scattering media gives rise to structural noise which makes it difficult to detect potential damage or crack inside the component. In order to predict the performances of ultrasonic inspection over such complex media, scattering models can be used. Such models rely on specific key parameters describing the multiple scattering process, which can be determined by specific measurements and post-processing techniques. Such experiments were carried out on stainless steel plates using linear phased-arrays. They consist in recording the response matrix constituted by impulse responses between all the elements of the array. By conducting post-processing on this matrix, we measure the elastic mean free path l e and the correlation distance d c of the recorded noise. Additionally, the dynamic behaviour of the coherent backscattering effect was studied in order to measure the diffusion constant D. Plane-wave beamforming has been applied to the response matrix to improve the angular resolution and the signal-to-noise ratio of the backscattered intensity. Details of postprocessing techniques will be shown
Compton scatter correction in case of multiple crosstalks in SPECT imaging.
Sychra, J J; Blend, M J; Jobe, T H
1996-02-01
A strategy for Compton scatter correction in brain SPECT images was proposed recently. It assumes that two radioisotopes are used and that a significant portion of photons of one radioisotope (for example, Tc99m) spills over into the low energy acquisition window of the other radioisotope (for example, Tl201). We are extending this approach to cases of several radioisotopes with mutual, multiple and significant photon spillover. In the example above, one may correct not only the Tl201 image but also the Tc99m image corrupted by the Compton scatter originating from the small component of high energy Tl201 photons. The proposed extension is applicable to other anatomical domains (cardiac imaging).
Scattering by multiple parallel radially stratified infinite cylinders buried in a lossy half space.
Lee, Siu-Chun
2013-07-01
The theoretical solution for scattering by an arbitrary configuration of closely spaced parallel infinite cylinders buried in a lossy half space is presented in this paper. The refractive index and permeability of the half space and cylinders are complex in general. Each cylinder is radially stratified with a distinct complex refractive index and permeability. The incident radiation is an arbitrarily polarized plane wave propagating in the plane normal to the axes of the cylinders. Analytic solutions are derived for the electric and magnetic fields and the Poynting vector of backscattered radiation emerging from the half space. Numerical examples are presented to illustrate the application of the scattering solution to calculate backscattering from a lossy half space containing multiple homogeneous and radially stratified cylinders at various depths and different angles of incidence.
On the solution of a few problems of multiple scattering by Monte Carlo method
International Nuclear Information System (INIS)
Bluet, J.C.
1966-02-01
Three problems of multiple scattering arising from neutron cross sections experiments, are reported here. The common hypothesis are: - Elastic scattering is the only possible process - Angular distributions are isotropic - Losses of particle energy are negligible in successive collisions. In the three cases practical results, corresponding to actual experiments are given. Moreover the results are shown in more general way, using dimensionless variable such as the ratio of geometrical dimensions to neutron mean free path. The FORTRAN codes are given together with to the corresponding flow charts, and lexicons of symbols. First problem: Measurement of sodium capture cross-section. A sodium sample of given geometry is submitted to a neutron flux. Induced activity is then measured by means of a sodium iodide cristal. The distribution of active nuclei in the sample, and the counter efficiency are calculated by Monte-Carlo method taking multiple scattering into account. Second problem: absolute measurement of a neutron flux using a glass scintillator. The scintillator is a use of lithium 6 loaded glass, submitted to neutron flux perpendicular to its plane faces. If the glass thickness is not negligible compared with scattering mean free path λ, the mean path e' of neutrons in the glass is different from the thickness. Monte-Carlo calculation are made to compute this path and a relative correction to efficiency equal to (e' - e)/e. Third problem: study of a neutron collimator. A neutron detector is placed at the bottom of a cylinder surrounded with water. A neutron source is placed on the cylinder axis, in front of the water shield. The number of neutron tracks going directly and indirectly through the water from the source to the detector are counted. (author) [fr
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.
International Nuclear Information System (INIS)
Jiang Weizhou; Li Baoan; Chen Liewen
2007-01-01
The mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter are investigated using the nucleon optical potential obtained within the relativistic impulse approximation with the empirical nucleon-nucleon scattering amplitudes and the nuclear densities obtained in the relativistic mean-field model. It is found that the isospin-splitting of nucleon mean free paths, sensitive to the imaginary part of the symmetry potential, changes its sign at certain high kinetic energy. The in-medium nucleon-nucleon cross sections are analytically and numerically demonstrated to be essentially independent of the isospin asymmetry of the medium and increase linearly with density in the high-energy region where the relativistic impulse approximation is applicable
Thomson, C. J.
2004-12-01
Pseudodifferential operators (PSDOs) yield in principle exact one--way seismic wave equations, which are attractive both conceptually and for their promise of computational efficiency. The one--way operators can be extended to include multiple--scattering effects, again in principle exactly. In practice approximations must be made and, as an example, the variable--wavespeed Helmholtz equation for scalar waves in two space dimensions is here factorized to give the one--way wave equation. This simple case permits clear identification of a sequence of physically reasonable approximations to be used when the mathematically exact PSDO one--way equation is implemented on a computer. As intuition suggests, these approximations hinge on the medium gradients in the direction transverse to the main propagation direction. A key point is that narrow--angle approximations are to be avoided in the interests of accuracy. Another key consideration stems from the fact that the so--called ``standard--ordering'' PSDO indicates how lateral interpolation of the velocity structure can significantly reduce computational costs associated with the Fourier or plane--wave synthesis lying at the heart of the calculations. The decision on whether a slow or a fast Fourier transform code should be used rests upon how many lateral model parameters are truly distinct. A third important point is that the PSDO theory shows what approximations are necessary in order to generate an exponential one--way propagator for the laterally varying case, representing the intuitive extension of classical integral--transform solutions for a laterally homogeneous medium. This exponential propagator suggests the use of larger discrete step sizes, and it can also be used to approach phase--screen like approximations (though the latter are not the main interest here). Numerical comparisons with finite--difference solutions will be presented in order to assess the approximations being made and to gain an understanding
International Nuclear Information System (INIS)
Curiel-Garcia, Quiela-Marina
2014-01-01
One of the goals of the COMPASS experience is the study of the nucleon spin structure. Data were taken from a polarized muon beam (160 GeV/c) scattering off a polarized target ( 6 LiD or NH 3 ). In this context, the need of a precise knowledge of quark Fragmentation Functions (final-state hadronization of quarks q into hadrons h, FFs) was raised. The FFs can be extracted from hadron multiplicities produced in Semi-Inclusive Deep Inelastic Scattering (SIDIS). This thesis presents the measurement of charged hadrons (pions and kaons) multiplicities from SIDIS data collected in 2006. The data cover a large kinematical range: Q 2 ≥1 (GeV/c)2, y belongs to [0.1,0.9], x belongs to [0.004,0.7] and W belongs to [5,17] GeV. These multiplicities provide an important input for global QCD analyses of world data at NLO, aiming at the FFs determination. (author) [fr
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 learning from either 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.
Modified random hinge transport mechanics and multiple scattering step-size selection in EGS5
International Nuclear Information System (INIS)
Wilderman, S.J.; Bielajew, A.F.
2005-01-01
The new transport mechanics in EGS5 allows for significantly longer electron transport step sizes and hence shorter computation times than required for identical problems in EGS4. But as with all Monte Carlo electron transport algorithms, certain classes of problems exhibit step-size dependencies even when operating within recommended ranges, sometimes making selection of step-sizes a daunting task for novice users. Further contributing to this problem, because of the decoupling of multiple scattering and continuous energy loss in the dual random hinge transport mechanics of EGS5, there are two independent step sizes in EGS5, one for multiple scattering and one for continuous energy loss, each of which influences speed and accuracy in a different manner. Further, whereas EGS4 used a single value of fractional energy loss (ESTEPE) to determine step sizes at all energies, to increase performance by decreasing the amount of effort expended simulating lower energy particles, EGS5 permits the fractional energy loss values which are used to determine both the multiple scattering and continuous energy loss step sizes to vary with energy. This results in requiring the user to specify four fractional energy loss values when optimizing computations for speed. Thus, in order to simplify step-size selection and to mitigate step-size dependencies, a method has been devised to automatically optimize step-size selection based on a single material dependent input related to the size of problem tally region. In this paper we discuss the new transport mechanics in EGS5 and describe the automatic step-size optimization algorithm. (author)
Multiple X-ray tomography using transmitted, scattered and fluorescent radiation
International Nuclear Information System (INIS)
Cesareo, R.; Brunetti, A.; Golosio, B.; Lopes, R.T.; Barroso, R.C.; Donativi, M.; Castellano, A.; Quarta, S.
2003-01-01
A multiple CT-scanner is described, which contemporaneously uses transmitted, scattered and fluorescent X-rays for Imaging. The scanner is characterized by a small size X-ray tube and by four detectors: a ''pencil'' X-ray NaI(Tl) for transmitted tomography, a larger size NaI(Tl) for 90 C o Compton tomography, a thermoelectrically cooled Si-PIN or CdZnTe for fluorescent imaging and a CdZnTe for Rayleigh (or diffraction) tomography. Examples of applications are shown
Multiple-scattering and DV-Xα analyses of a Cl-passivated Ge(111) surface
International Nuclear Information System (INIS)
Cao, S; Tang, J-C; Shen, S-L
2003-01-01
The multiple-scattering cluster and DV-Xα methods have been employed to analyse the chlorine 1s near edge x-ray absorption fine structure (NEXAFS) of a Cl-passivated Ge(111) surface. Our detailed analysis demonstrates how the chlorine atoms form a perfect monochloride structure with Cl bonding to the topmost Ge atom. Our calculation reveals the interaction in the chlorine layer is multipolar electrostatic forces. Furthermore, the DV-Xα cluster calculation shows that the orbital contour of the sharp Cl-Ge resonance exhibits a global symmetry, which confirms it to be σ * -like. The above studies are found to enrich previous experimental NEXAFS investigations
Topological cross sections in hadron-nucleus collisions and multiple scattering theory
International Nuclear Information System (INIS)
Zoller, V.R.
1987-01-01
The multiple scattering theory supplemented with cutting rules of Abramovsky, V.A., Gribov, V.N., Kancheli, O.V. is applied to calculation of the hadron-nucleus interaction cross sections. In contrast to standard Glauber approach neither smalness of the interaction radius compared to the nuclear radii nor Gaussian form of the hN-interaction profile function are assumed. The theory of the supercritical pomeron are used. However all the results are more general and do not depend on the parametrization of the pomeron pole amplitude. The region of validity of the widely used approximate formulae for topological and total hA-interaction cross sections are discussed
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......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...
Energy Technology Data Exchange (ETDEWEB)
Wielunski, L S [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics
1997-12-31
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.
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.
Otsuki, Soichi
2016-02-01
This paper presents a theory describing totally incoherent multiple scattering of turbid spherical samples. It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in spherical samples. Monte Carlo simulations generate a reduced effective scattering Mueller matrix, which virtually satisfies reciprocity and mirror symmetry. The scattering matrix was factorized by using the symmetric decomposition in a predefined form, as well as the Lu-Chipman polar decomposition, approximately into a product of a pure depolarizer and vertically oriented linear retarding diattenuators. The parameters of these components were calculated as a function of the polar angle. While the turbid spherical sample is a pure depolarizer at low polar angles, it obtains more functions of the retarding diattenuator with increasing polar angle.
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.
Wang, Zuowei; Biwa, Shiro
2018-03-01
A numerical procedure is proposed for the multiple scattering analysis of flexural waves on a thin plate with circular holes based on the Kirchhoff plate theory. The numerical procedure utilizes the wave function expansion of the exciting as well as scattered fields, and the boundary conditions at the periphery of holes are incorporated as the relations between the expansion coefficients of exciting and scattered fields. A set of linear algebraic equations with respect to the wave expansion coefficients of the exciting field alone is established by the numerical collocation method. To demonstrate the applicability of the procedure, the stop band characteristics of flexural waves are analyzed for different arrangements and concentrations of circular holes on a steel plate. The energy transmission spectra of flexural waves are shown to capture the detailed features of the stop band formation of regular and random arrangements of holes. The increase of the concentration of holes is found to shift the dips of the energy transmission spectra toward higher frequencies as well as deepen them. The hexagonal hole arrangement can form a much broader stop band than the square hole arrangement for flexural wave transmission. It is also demonstrated that random arrangements of holes make the transmission spectrum more complicated.
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.
Multiple Coulomb scattering of high-energy heavy charged particle beams used in biology and medicine
International Nuclear Information System (INIS)
Wong, M.; Schimmerling, W.; Ludewigt, B.; Phillips, M.; Curtis, S.; Tobias, C.A.
1987-01-01
The authors measured lateral displacement and angular distributions of high-energy heavy charged particles emerging from a target at the Lawrence Berkeley Laboratory BEVALAC with beams used in radiobiology experiments. Multiple Coulomb scattering occurring in the target material generally spreads the beam laterally and increases its divergence. The apparatus consists of four sets of position-sensitive semiconductor detectors located along the beam line. Each providing two position signals and one energy signal. The difference between the two position signals is used to determine the particle position in one dimension. The two position signals are constrained to add up to the energy deposition signal in order to reject multiple-particle traversals. The vector directions for the incident and emerging particles are reconstructed in three dimensions from their measured coordinated positions. Lateral and angular distributions are reported for beams of high-energy neon, iron and uranium ions incident on targets of aluminum, cooper, lead and water
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.)
Energy dependence of the charged multiplicity in deep inelastic scattering at HERA
International Nuclear Information System (INIS)
Chekanov, S.; Derrick, M.; Magill, S.
2008-03-01
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 -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 + e - 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.
Reichardt, J; Hess, M; Macke, A
2000-04-20
Multiple-scattering correction factors for cirrus particle extinction coefficients measured with Raman and high spectral resolution lidars are calculated with a radiative-transfer model. Cirrus particle-ensemble phase functions are computed from single-crystal phase functions derived in a geometrical-optics approximation. Seven crystal types are considered. In cirrus clouds with height-independent particle extinction coefficients the general pattern of the multiple-scattering parameters has a steep onset at cloud base with values of 0.5-0.7 followed by a gradual and monotonic decrease to 0.1-0.2 at cloud top. The larger the scattering particles are, the more gradual is the rate of decrease. Multiple-scattering parameters of complex crystals and of imperfect hexagonal columns and plates can be well approximated by those of projected-area equivalent ice spheres, whereas perfect hexagonal crystals show values as much as 70% higher than those of spheres. The dependencies of the multiple-scattering parameters on cirrus particle spectrum, base height, and geometric depth and on the lidar parameters laser wavelength and receiver field of view, are discussed, and a set of multiple-scattering parameter profiles for the correction of extinction measurements in homogeneous cirrus is provided.
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.
Spectrometer for Particle Characterization With a New Multiple-Scattering Theory, Phase I
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,...
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
International Nuclear Information System (INIS)
Mitri, F G
2017-01-01
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
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.
International Nuclear Information System (INIS)
Wiblin, R.T.; Edmonds, K.; Ellner, J.J.
1986-01-01
The human macrophage-like cell line U937 spontaneously produces a factor which blocks interleukin-1 (IL-1) activity for mouse thymocytes but not mitosis of T-lymphoblastoid cells. The authors examined the effects of U937 conditioned medium (CM) on other IL-1 activities and on interleukin-2 (IL-2) production. U937 was cultured at 5 x 10 6 /ml in RPMI-1640 at 37 0 C for 5 days. The resulting CM inhibited the mitogenic response of C3H/HeJ mouse thymocytes to an IL-1 standard, with an inhibitory of activity of 6.64 U/ml (1 U = reciprocal dilution producing 50% inhibition of maximal response). Similarly, CM inhibited (10.12 U/ml) the fibroblast stimulation promoter activity of IL-1. The effect of CM on IL-2 production was assessed in a direct assay in which IL-2 production by γ-irradiated (12,000 rads) MLA-144 lymphosarcoma cells was assayed as 3 H-thymidine incorporation in CTLL-20 cells. The suppressive activity of CM was 4.95 U/ml; CM did not interfere with the response of CTLL-20 to IL-2. These studies establish that U937 produces factors with multiple, related biological activities; U937 CM blocks IL-2 dependent (thymocyte mitogenesis) and IL-2 independent (fibroblast proliferation) IL-1 activities and interferes with production of, but not response to, IL-2. U937 is an excellent model to study growth inhibitory properties of mononuclear phagocytes
International Nuclear Information System (INIS)
Freiv, A V; Roshchupkin, S P
2008-01-01
The possibility of amplification of electromagnetic radiation is theoretically studied in the scattering of a quasi-classical electron by an ion in a field of linearly polarized waves of medium intensity. An expression for the total cross-section (the gain coefficient) for the wide interval of values of the adiabaticity parameter is obtained. It is shown that the wave amplification takes place in the range of values of adiabaticity parameter greater than 2 and can be sufficiently large
International Nuclear Information System (INIS)
Neumayer, P
2007-01-01
A long-standing problem in the field of laser-plasma interactions is to successfully employ multiple-ion species plasmas to reduce stimulated Brillouin scattering (SBS) in inertial confinement fusion (ICF) hohlraum conditions. Multiple-ion species increase significantly the linear Landau damping for acoustic waves. Consequently, recent hohlraum designs for indirect-drive ignition on the National Ignition Facility investigate wall liner material options so that the liner gain for parametric instabilities will be below threshold for the onset SBS. Although the effect of two-ion species plasmas on Landau damping has been directly observed with Thomson scattering, early experiments on SBS in these plasmas have suffered from competing non-linear effects or laser beam filamentation. In this study, a reduction of SBS scattering to below the percent level has been observed in hohlraums at Omega that emulate the plasma conditions in an indirect drive ICF experiments. These experiments have measured the laser-plasma interaction processes in ignition-relevant high-electron temperature regime demonstrating Landau damping as a controlling process for SBS. The hohlraums have been filled with various fractions of CO 2 and C 3 H 8 varying the ratio of the light (H) to heavy (C and O) ion density from 0 to 2.6. They have been heated by 14.5 kJ of 351-nm light, thus increasing progressively Landau damping by an order of magnitude at constant electron density and temperature. A delayed 351-nm interaction beam, spatially smoothed to produce a 200-(micro)m laser spot at best focus, has propagated along the axis of the hohlraum. The backscattered light, both into the lens and outside, the transmitted light through the hohlraum plasma and the radiation temperature of the hohlraum has been measured. For ignition relevant laser intensities (3-9 10 14 Wcm -2 ), we find that the SBS reflectivity scales as predicted with Landau damping from >30% to <1%. Simultaneously, the hohlraum radiation
Kinnunen, Matti; Kauppila, Antti; Karmenyan, Artashes; Myllylä, Risto
2011-09-15
Optical tweezers can be used to manipulate small objects and cells. A trap can be used to fix the position of a particle during light scattering measurements. The places of two separately trapped particles can also be changed. In this Letter we present elastic light scattering measurements as a function of scattering angle when two trapped spheres are illuminated with a He-Ne laser. This setup is suitable for trapping noncharged homogeneous spheres. We also demonstrate measurement of light scattering patterns from two separately trapped red blood cells. Two different illumination schemes are used for both samples.
Analysis of multiple scattering contributions in electron-impact ionization of molecular hydrogen
Ren, Xueguang; Hossen, Khokon; Wang, Enliang; Pindzola, M. S.; Dorn, Alexander; Colgan, James
2017-10-01
We report a combined experimental and theoretical study on the low-energy (E 0 = 31.5 eV) electron-impact ionization of molecular hydrogen (H2). Triple differential cross sections are measured for a range of fixed emission angles of one outgoing electron between {θ }1=-70^\\circ and -130° covering the full 4π solid angle of the second electron. The energy sharing of the outgoing electrons varies from symmetric ({E}1={E}2=8 eV) to highly asymmetric (E 1 = 1 eV and E 2 = 15 eV). In addition to the binary and recoil lobes, a structure is observed perpendicular to the incoming beam direction which is due to multiple scattering of the projectile inside the molecular potential. The absolutely normalized experimental cross sections are compared with results from the time-dependent close-coupling (TDCC) calculations. Molecular alignment dependent TDCC results demonstrate that these structures are only present if the molecule axis is lying in the scattering plane.
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...
Modified Moliere's screening parameter and its impact on multiple coulomb scattering
International Nuclear Information System (INIS)
Striganov, Sergei
2015-01-01
The Moliere approximation of elastic Coulomb scattering cross-sections plays an important role in accurate description of multiple scattering, non-ionisation energy, DPA radiation damage etc. The cross-section depends only on a single parameter that describes the atomic screening. Moliere calculated the screening angle for the Tomas-Fermi distribution of electrons in atoms. In this paper, the screening parameter was recalculated using a more accurate atomic form-factor obtained from the self-consistent Dirac-Hartree-Fock-Slater computations. For relativistic particles, the new screening angle can differ from the Moliere approximation by up to 50%. At the same time, it is rather close to other independent calculations. At low energies, the new screening angle is different for positrons and electrons. The positron screening parameter is much larger than the electron one for heavy nuclei at energies of ∼Z keV. The impact of the screening angle on particle transport and calculated quantities is discussed. (authors)
Diffusion equations and hard collisions in multiple scattering of charged particles
International Nuclear Information System (INIS)
Papiez, Lech; Tulovsky, Vladimir
1998-01-01
The processes of angular-spatial evolution of multiple scattering of charged particles are described by the Lewis (special case of Boltzmann) integro-differential equation. The underlying stochastic process for this evolution is the compound Poisson process with transition densities satisfying the Lewis equation. In this paper we derive the Lewis equation from the compound Poisson process and show that the effective method of the solution of this equation can be based on the idea of decomposition of the compound Poisson process into processes of soft and hard collisions. Formulas for transition densities of soft and hard collision processes are provided in this paper together with the formula expressing the general solution of the Lewis equation in terms of those transition densities
Anderson, D. E., Jr.; Meier, R. R.; Hodges, R. R., Jr.; Tinsley, B. A.
1987-01-01
The H Balmer alpha nightglow is investigated by using Monte Carlo models of asymmetric geocoronal atomic hydrogen distributions as input to a radiative transfer model of solar Lyman-beta radiation in the thermosphere and atmosphere. It is shown that it is essential to include multiple scattering of Lyman-beta radiation in the interpretation of Balmer alpha airglow data. Observations of diurnal variation in the Balmer alpha airglow showing slightly greater intensities in the morning relative to evening are consistent with theory. No evidence is found for anything other than a single sinusoidal diurnal variation of exobase density. Dramatic changes in effective temperature derived from the observed Balmer alpha line profiles are expected on the basis of changing illumination conditions in the thermosphere and exosphere as different regions of the sky are scanned.
The Green Function cellular method and its relation to multiple scattering theory
International Nuclear Information System (INIS)
Butler, W.H.; Zhang, X.G.; Gonis, A.
1992-01-01
This paper investigates techniques for solving the wave equation which are based on the idea of obtaining exact local solutions within each potential cell, which are then joined to form a global solution. The authors derive full potential multiple scattering theory (MST) from the Lippmann-Schwinger equation and show that it as well as a closely related cellular method are techniques of this type. This cellular method appears to have all of the advantages of MST and the added advantage of having a secular matrix with only nearest neighbor interactions. Since this cellular method is easily linearized one can rigorously reduce electronic structure calculation to the problem of solving a nearest neighbor tight-binding problem
Diffusion equations and hard collisions in multiple scattering of charged particles
Energy Technology Data Exchange (ETDEWEB)
Papiez, Lech [Department of Radiation Oncology, Indiana University, Indianapolis, IN (United States); Tulovsky, Vladimir [Department of Mathematics, St. John' s College, Staten Island, New York, NY (United States)
1998-09-01
The processes of angular-spatial evolution of multiple scattering of charged particles are described by the Lewis (special case of Boltzmann) integro-differential equation. The underlying stochastic process for this evolution is the compound Poisson process with transition densities satisfying the Lewis equation. In this paper we derive the Lewis equation from the compound Poisson process and show that the effective method of the solution of this equation can be based on the idea of decomposition of the compound Poisson process into processes of soft and hard collisions. Formulas for transition densities of soft and hard collision processes are provided in this paper together with the formula expressing the general solution of the Lewis equation in terms of those transition densities.
Absorption imaging of a quasi-two-dimensional gas: a multiple scattering analysis
International Nuclear Information System (INIS)
Chomaz, L; Corman, L; Yefsah, T; Desbuquois, R; Dalibard, J
2012-01-01
Absorption imaging with quasi-resonant laser light is a commonly used technique for probing ultra-cold atomic gases in various geometries. In this paper, we investigate some non-trivial aspects of this method when applying the method to in situ diagnosis of a quasi-two-dimensional (2D) gas. Using Monte Carlo simulations we study the modification of the absorption cross-section of a photon when it undergoes multiple scattering in the gas. We determine the variations of the optical density with various parameters, such as the detuning of the light from the atomic resonance and the thickness of the gas. We compare our results to the known 3D result (the Beer-Lambert law) and outline the specific features of the 2D case. (paper)
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.
Superluminal two-color light in a multiple Raman gain medium
Kudriašov, V.; Ruseckas, J.; Mekys, A.; Ekers, Aigars; Bezuglov, N.; Juzeliūnas, G.
2014-01-01
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.
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.
International Nuclear Information System (INIS)
Peterson, G.A.
1981-08-01
Electron scattering experiments are in progress at the Bates Linear Accelerator in Middleton, Massachusetts. Both magnetic elastic and transverse inelastic scattering cross sections have been measured at 180 0 by the apparatus constructed and brought into operation in late 1977 by the University of Massachusetts. A liquid-nitrogen-cooled gas target is being used in a study of deuteron elastic magnetic scattering and electrodisintegration over a large energy range. A measurement of elastic magnetic and transverse inelastic scattering from 14 N has been started. Measurements of the elastic magnetic scattering from 13 C, 15 N, 27 Al, 29 Si, and 31 P have been completed. The data set on 15 N inelastic scattering are now complete and analysis of the data is in progress. A study of M8 transitions in 54 Fe and 60 Ni is nearing completion. Several papers are being written on these subjects. A measurement of the transverse quasi-elastic scattering from 56 Fe has been started. Planning for an experiment utilizing radioactive 14 C is underway. Large-basis shell model calculations pertaining to the above nuclei and others have been made. Theoretical calculations of exchange currents, nuclear convection currents, and other nuclear phenomena are in progress. Finally, considerations are being given to the design of an integrated storage-ring-experimental system
International Nuclear Information System (INIS)
Peterson, G.A.
1981-08-01
Electron scattering experiments are in progress at the Bates Linear Accelerator in Middleton, Massachusetts. Both magnetic elastic and transverse inelastic scattering cross sections have been measured at 180 0 by the apparatus constructed and brought into operation in late 1977 by the University of Massachusetts. A liquid-nitrogen-cooled gas target is being used in a study of deuteron elastic scattering and electrodisintegration over a large energy range. A measurement of elastic magnetic and transverse inelastic scattering from 14 N has been started. Measurements of the elastic magnetic scattering from 13 C, 15 N, 27 Al, 29 Si, and 31 P have been completed. The data set on 15 N inelastic scattering are now complete and analysis of the data is in progress. A study of M8 transitions in 54 Fe and 60 Ni is nearing completion. A measurement of the transverse quasielastic scattering from 56 Fe has been started. Planning for an experiment utilizing radioactive 14 C is underway. Large-basis shell model calculations pertaining to the above nuclei and others have been made. Theoretical calculations of exchange currents, nuclear convection currents, and other nuclear phenomena are in progress. Finally, considerations are being given to the design of an integrated storage-ring-experimental system
Multiple Scattering Analysis of Cu - K EXAFS in Bi2Sr1.5 Cu2O8+δ
International Nuclear Information System (INIS)
Roehler, J.; Cruesemann, R.
1995-01-01
We have analyzed the Cu K-EXAFS of Bi 2 Sr 1.5 Ca 1.5 Cu 2 O 8+δ using a full multiple scattering analysis in a cluster with diameter d∼ 7.6 A. The layered structure has numerous quasi one-dimensional structural elements which give rise to significant multiple scattering contributions in the EXAFS. We confirm the Sr/Ca ratio of the sample is 1:1, and one Ca atom is located close to a nominal Sr-site. At 40 K the dimpling angle in the CuO 2 -plane is found to be ≤ 3.5 . (author)
International Nuclear Information System (INIS)
Nagamatsu, S.; Ono, M.; Kera, S.; Okudaira, K. K.; Fujikawa, T.; Ueno, N.
2007-01-01
The polarization dependence of F K-edge X-ray absorption near edge structure (XANES) spectra of highly-oriented thin-film of polytetrafluoroethylene (PTFE) has been analyzed by using multiple scattering theory. The spectra show clear polarization dependence due to the highly-oriented structure. The multiple scattering calculations reflects a local structure around an absorbing atom. The calculated results obtained by considering intermolecular-interactions are in good agreement with the observed polarization-dependence. We have also analyzed structural models of the radiation damaged PTFE films
Stamnes, Knut; Tsay, S.-CHEE; Jayaweera, Kolf; Wiscombe, Warren
1988-01-01
The transfer of monochromatic radiation in a scattering, absorbing, and emitting plane-parallel medium with a specified bidirectional reflectivity at the lower boundary is considered. The equations and boundary conditions are summarized. The numerical implementation of the theory is discussed with attention given to the reliable and efficient computation of eigenvalues and eigenvectors. Ways of avoiding fatal overflows and ill-conditioning in the matrix inversion needed to determine the integration constants are also presented.
International Nuclear Information System (INIS)
Teterson, G.A.; Hicks, R.S.; Dubach, J.F.; Miskimen, R.A.
1987-06-01
This paper discusses the experimental electron scattering studies at SLAC and Bates Accelerator Center. Some theoretical work on nucleon-nucleon interactions, electromagnetic interactions, weak interactions and nuclear structure are also discussed
Energy Technology Data Exchange (ETDEWEB)
Redfield, Seth [Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT 06459-0123 (United States); Linsky, Jeffrey L., E-mail: sredfield@wesleyan.edu, E-mail: jlinsky@jila.colorado.edu [JILA, University of Colorado and NIST, Boulder, CO 80309-0440 (United States)
2015-10-20
Ultraviolet and optical spectra of interstellar gas along the lines of sight to nearby stars have been interpreted by Redfield and Linsky and previous studies as a set of discrete warm, partially ionized clouds each with a different flow vector, temperature, and metal depletion. Recently, Gry and Jenkins proposed a fundamentally different model consisting of a single cloud with nonrigid flows filling space out to 9 pc from the Sun that they propose better describes the local ISM. Here we test these fundamentally different morphological models against the spatially unbiased Malamut et al. spectroscopic data set, and find that the multiple cloud morphology model provides a better fit to both the new and old data sets. The detection of three or more velocity components along the lines of sight to many nearby stars, the presence of nearby scattering screens, the observed thin elongated structures of warm interstellar gas, and the likely presence of strong interstellar magnetic fields also support the multiple cloud model. The detection and identification of intercloud gas and the measurement of neutral hydrogen density in clouds beyond the Local Interstellar Cloud could provide future morphological tests.
Influence of multiple well defined conformations on small-angle scattering of proteins in solution.
Heller, William T
2005-01-01
A common structural motif for many proteins comprises rigid domains connected by a flexible hinge or linker. The flexibility afforded by these domains is important for proper function and such proteins may be able to adopt more than one conformation in solution under equilibrium conditions. Small-angle scattering of proteins in solution samples all conformations that exist in the sampled volume during the time of the measurement, providing an ensemble-averaged intensity. In this paper, the influence of sampling an ensemble of well defined protein structures on the small-angle solution scattering intensity profile is examined through common analysis methods. Two tests were performed using simulated data: one with the extended and collapsed states of the bilobal calcium-binding protein calmodulin and the second with the catalytic subunit of protein kinase A, which has two globular domains connected by a glycine hinge. In addition to analyzing the simulated data for the radii of gyration Rg, distance distribution function P(r) and particle volume, shape restoration was applied to the simulated data. Rg and P(r) of the ensemble profiles could be easily mistaken for a single intermediate state. The particle volumes and models of the ensemble intensity profiles show that some indication of multiple conformations exists in the case of calmodulin, which manifests an enlarged volume and shapes that are clear superpositions of the conformations used. The effect on the structural parameters and models is much more subtle in the case of the catalytic subunit of protein kinase A. Examples of how noise influences the data and analyses are also presented. These examples demonstrate the loss of the indications of multiple conformations in cases where even broad distributions of structures exist. While the tests using calmodulin show that the ensemble states remain discernible from the other ensembles tested or a single partially collapsed state, the tests performed using the
Czech Academy of Sciences Publication Activity Database
Adolph, C.; Aghasyan, M.; Akhunzyanov, R.; Alexeev, G. D.; Alexeev, M.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Barth, J.; Beck, D.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bisplinghoff, J.; Bodlák, 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.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; 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 jr., M.; Fischer, H.; Franco, C.; 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-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; von Harrach, D.; Hashimoto, R.; Heinsius, F. H.; Heitz, R.; Herrmann, E.; Hinterberger, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jarý, V.; Joosten, R.; Jörg, P.; Kabuss, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; 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.; 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.; Rybnikov, A.; Rychter, A.; Salač, 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.; Smolík, J.; Sozzi, F.; Srnka, Aleš; Steffen, D.; Stolarski, M.; Šulc, 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.; Závada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Zink, A.
2017-01-01
Roč. 764, JAN (2017), s. 1-10 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : deep inelastic scattering * pion multiplicities * fragmentation functions Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Nuclear physics Impact factor: 4.807, year: 2016
Energy Technology Data Exchange (ETDEWEB)
Benton, Christopher J., E-mail: cjb30@bath.ac.uk [Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Smith, Nathan D. [Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Quillin, Stephen J.; Steer, Christopher A. [AWE, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom)
2012-11-21
Tomographic imaging using cosmic ray muons has a range of applications including homeland security and geological imaging. To this end, we have developed a technique to calculate the most probable muon trajectory through a scattering material, given its measured entry and exit trajectories. This method has the potential to improve tomographic algorithms, in particular by replacing the muon paths assumed by the Point Of Closest Approach (POCA) method, with more realistic paths. These paths can be calculated for arbitary matter distributions, rather than just the point scatterers assumed by POCA.
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.
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.)
Band structures in a two-dimensional phononic crystal with rotational multiple scatterers
Song, Ailing; Wang, Xiaopeng; Chen, Tianning; Wan, Lele
2017-03-01
In this paper, the acoustic wave propagation in a two-dimensional phononic crystal composed of rotational multiple scatterers is investigated. The dispersion relationships, the transmission spectra and the acoustic modes are calculated by using finite element method. In contrast to the system composed of square tubes, there exist a low-frequency resonant bandgap and two wide Bragg bandgaps in the proposed structure, and the transmission spectra coincide with band structures. Specially, the first bandgap is based on locally resonant mechanism, and the simulation results agree well with the results of electrical circuit analogy. Additionally, increasing the rotation angle can remarkably influence the band structures due to the transfer of sound pressure between the internal and external cavities in low-order modes, and the redistribution of sound pressure in high-order modes. Wider bandgaps are obtained in arrays composed of finite unit cells with different rotation angles. The analysis results provide a good reference for tuning and obtaining wide bandgaps, and hence exploring the potential applications of the proposed phononic crystal in low-frequency noise insulation.
Multiple parton interactions in deep inelastic ep-scattering at HERA
International Nuclear Information System (INIS)
Osman, Sakar
2008-12-01
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 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 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.)
Fully-relativistic full-potential multiple scattering theory: A pathology-free scheme
Liu, Xianglin; Wang, Yang; Eisenbach, Markus; Stocks, G. Malcolm
2018-03-01
The Green function plays an essential role in the Korringa-Kohn-Rostoker(KKR) multiple scattering method. In practice, it is constructed from the regular and irregular solutions of the local Kohn-Sham equation and robust methods exist for spherical potentials. However, when applied to a non-spherical potential, numerical errors from the irregular solutions give rise to pathological behaviors of the charge density at small radius. Here we present a full-potential implementation of the fully-relativistic KKR method to perform ab initio self-consistent calculation by directly solving the Dirac differential equations using the generalized variable phase (sine and cosine matrices) formalism Liu et al. (2016). The pathology around the origin is completely eliminated by carrying out the energy integration of the single-site Green function along the real axis. By using an efficient pole-searching technique to identify the zeros of the well-behaved Jost matrices, we demonstrated that this scheme is numerically stable and computationally efficient, with speed comparable to the conventional contour energy integration method, while free of the pathology problem of the charge density. As an application, this method is utilized to investigate the crystal structures of polonium and their bulk properties, which is challenging for a conventional real-energy scheme. The noble metals are also calculated, both as a test of our method and to study the relativistic effects.
International Nuclear Information System (INIS)
Henk, J.
2004-01-01
Electron spectroscopy provides access to fundamental properties of solids, such as the geometric, electronic, and the magnetic structure. The latter are necessary for the understanding of a variety of basic but nevertheless important effects. The present work outlines recently developed theoretical approaches to electron spectroscopies. Most of the collected results rely on first-principles calculations, as formulated in multiple-scattering theory, and are contrasted with experimental findings. One topic involves spin- and angle-resolved photoelectron spectroscopy which is addressed for magnetic surfaces and ultrathin films. Exemplary results comprise magnetic dichroism in both valence-band and core-level photoemission as well as the temperature dependence of magnetic properties of ultrathin films. Another topic is spin-dependent ballistic transport through planar tunnel junctions, focusing here on the zero-bias anomaly. In most of the cases, spin-orbit coupling (SOC) is an essential ingredient and, hence, favors a relativistic description. Prominent effects of SOC are illustrated by means of the electronic structure of rare gases adsorbed on a substrate and by the splitting of surface states on Au(111). Concerning magnetism, the magnetic anisotropy of Ni films on Cu(001) is discussed, focusing in particular on the spin reorientation transition induced by lattice distortions in ultrathin films. (orig.)
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)
Love, Steven P.; Davis, Anthony B.; Rohde, Charles A.; Tellier, Larry; Ho, Cheng
2002-09-01
At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60-degree full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer, and, from there, estimate the volume-averaged liquid water content. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Here we present recent WAIL data on various clouds and discuss the extension of WAIL to full diurnal monitoring by means of an ultra-narrow magneto-optic atomic line filter for daytime measurements.
International Nuclear Information System (INIS)
Love, Steven P.; Davis, Anthony B.; Rohde, Charles A.; Tellier, Larry L.; Ho, Cheng
2002-01-01
At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60-degree full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer, and, from there, estimate the volume-averaged liquid water content. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Here we present recent WAIL data oti various clouds and discuss the extension of WAIL to full diurnal monitoring by means of an ultra-narrow magneto-optic atomic line filter for daytime measurements.
Multiple Scattering Principal Component-based Radiative Transfer Model (PCRTM) from Far IR to UV-Vis
Liu, X.; Wu, W.; Yang, Q.
2017-12-01
Modern satellite hyperspectral satellite remote sensors such as AIRS, CrIS, IASI, CLARREO all require accurate and fast radiative transfer models that can deal with multiple scattering of clouds and aerosols to explore the information contents. However, performing full radiative transfer calculations using multiple stream methods such as discrete ordinate (DISORT), doubling and adding (AD), successive order of scattering order of scattering (SOS) are very time consuming. We have developed a principal component-based radiative transfer model (PCRTM) to reduce the computational burden by orders of magnitudes while maintain high accuracy. By exploring spectral correlations, the PCRTM reduce the number of radiative transfer calculations in frequency domain. It further uses a hybrid stream method to decrease the number of calls to the computational expensive multiple scattering calculations with high stream numbers. Other fast parameterizations have been used in the infrared spectral region reduce the computational time to milliseconds for an AIRS forward simulation (2378 spectral channels). The PCRTM has been development to cover spectral range from far IR to UV-Vis. The PCRTM model have been be used for satellite data inversions, proxy data generation, inter-satellite calibrations, spectral fingerprinting, and climate OSSE. We will show examples of applying the PCRTM to single field of view cloudy retrievals of atmospheric temperature, moisture, traces gases, clouds, and surface parameters. We will also show how the PCRTM are used for the NASA CLARREO project.
A hybrid approach to simulate multiple photon scattering in X-ray imaging
International Nuclear Information System (INIS)
Freud, N.; Letang, J.-M.; Babot, D.
2005-01-01
A hybrid simulation approach is proposed to compute the contribution of scattered radiation in X- or γ-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
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.
Directory of Open Access Journals (Sweden)
Gouveia Diego
2018-01-01
Full Text Available Lidar measurements of cirrus clouds are highly influenced by multiple scattering (MS. We therefore developed an iterative approach to correct elastic backscatter lidar signals for multiple scattering to obtain best estimates of single-scattering cloud optical depth and lidar ratio as well as of the ice crystal effective radius. The approach is based on the exploration of the effect of MS on the molecular backscatter signal returned from above cloud top.
Gouveia, Diego; Baars, Holger; Seifert, Patric; Wandinger, Ulla; Barbosa, Henrique; Barja, Boris; Artaxo, Paulo; Lopes, Fabio; Landulfo, Eduardo; Ansmann, Albert
2018-04-01
Lidar measurements of cirrus clouds are highly influenced by multiple scattering (MS). We therefore developed an iterative approach to correct elastic backscatter lidar signals for multiple scattering to obtain best estimates of single-scattering cloud optical depth and lidar ratio as well as of the ice crystal effective radius. The approach is based on the exploration of the effect of MS on the molecular backscatter signal returned from above cloud top.
International Nuclear Information System (INIS)
Butterfield, M.T.; Crapper, M.D.; Noakes, T.C.Q.; Bailey, P.; Jackson, G.J.; Woodruff, D.P.
2000-01-01
Applications of the techniques of normal-incidence x-ray standing wave (NIXSW) and medium-energy ion scattering (MEIS) to the elucidation of the structure of an ultrathin metallic film, Co on Cu(111), are reported. NIXSW and MEIS are shown to yield valuable and complementary information on the structure of such systems, yielding both the local stacking sequence and the global site distribution. For the thinnest films of nominally two layers, the first layer is of entirely fcc registry with respect to the substrate, but in the outermost layer there is significant occupation of hcp local sites. For films up to 8 monolayers (ML) thick, the interlayer spacing of the Co layers is 0.058±0.006 Aa smaller than the Cu substrate (111) layer spacing. With increasing coverage, the coherent fraction of the (1(bar sign)11) NIXSW decreases rapidly, indicating that the film does not grow in a fcc continuation beyond two layers. For films in this thickness range, hcp-type stacking dominates fcc twinning by a ratio of 2:1. The variation of the (1(bar sign)11) NIXSW coherent fraction with thickness shows that the twinning occurs close to the Co/Cu interface. For thicker films of around 20 ML deposited at room temperature, medium-energy ion scattering measurements reveal a largely disordered structure. Upon annealing to 300 deg. C the 20-ML films order into a hcp structure
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
Yurkin, Maxim A.; Mishchenko, Michael I.
2018-04-01
We present a general derivation of the frequency-domain volume integral equation (VIE) for the electric field inside a nonmagnetic scattering object from the differential Maxwell equations, transmission boundary conditions, radiation condition at infinity, and locally-finite-energy condition. The derivation applies to an arbitrary spatially finite group of particles made of isotropic materials and embedded in a passive host medium, including those with edges, corners, and intersecting internal interfaces. This is a substantially more general type of scatterer than in all previous derivations. We explicitly treat the strong singularity of the integral kernel, but keep the entire discussion accessible to the applied scattering community. We also consider the known results on the existence and uniqueness of VIE solution and conjecture a general sufficient condition for that. Finally, we discuss an alternative way of deriving the VIE for an arbitrary object by means of a continuous transformation of the everywhere smooth refractive-index function into a discontinuous one. Overall, the paper examines and pushes forward the state-of-the-art understanding of various analytical aspects of the VIE.
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.
International Nuclear Information System (INIS)
Li, Z.J.; Wu, Z.S.; Qu, T.; Shang, Q.C.; Bai, L.
2016-01-01
Based on the generalized multiparticle Mie theory, multiple scattering of an aggregate of uniaxial anisotropic spheres illuminated by a zero-order Bessel beam (ZOBB) with arbitrary propagation direction is investigated. The particle size and configuration are arbitrary. The arbitrary incident Bessel beam is expanded in terms of spherical vector wave functions (SVWFs). Utilizing the vector addition theorem of SVWFs, interactive and total scattering coefficients are derived through the continuous boundary conditions on which the interaction of the particles is considered. The accuracy of the theory and codes are verified by comparing results with those obtained for arbitrary plane wave incidence by CST simulation, and for ZOBB incidence by a numerical method. The effects of angle of incidence, pseudo-polarization angle, half-conical angle, beam center position, and permittivity tensor elements on the radar cross sections (RCSs) of several types of collective uniaxial anisotropic spheres, such as a linear chain, a 4×4×4 cube-shaped array, and other periodical structures consisting of massive spheres, are numerically analyzed. Selected results on the properties of typical particles such as TiO 2 , SiO 2 , or other particle lattices are calculated. This investigation could provide an effective test for further research on the scattering characteristics of an aggregate of anisotropic spheres by a high-order Bessel vortex beam. The results have important application in optical tweezers and particle manipulation. - Highlights: • Scattering of Bessel beam by an aggregate of uniaxial anisotropic spheres is studied. • The zero-order Bessel beam propagates and polarizes along arbitrary direction. • The accuracy of expansion coefficients, the scattering theory and codes is verified. • Effects of various parameters on scattering properties are numerically discussed. • Scattering properties of several type of periodical array are numerically analyzed.
International Nuclear Information System (INIS)
Budak, Vladimir P.; Korkin, Sergey V.
2008-01-01
The authors developed a numerical method of the boundary-value problem solution in the vectorial radiative transfer theory applicable to the turbid media with an arbitrary three-dimensional geometry. The method is based on the solution representation as the sum of an anisotropic part that contains all the singularities of the exact solution and a smooth regular part. The regular part of the solution could be found numerically by the finite element method that enables to extend the approach to the arbitrary medium geometry. The anisotropic part of the solution is determined analytically by the special form of the small-angle approximation. The method development is performed by the examples of the boundary-value problems for the plane unidirectional and point isotropic sources in a turbid medium slab
Zhao, Yaqin; Zhong, Xin; Wu, Di; Zhang, Ye; Ren, Guanghui; Wu, Zhilu
2013-09-01
Optical code-division multiple access (OCDMA) systems usually allocate orthogonal or quasi-orthogonal codes to the active users. When transmitting through atmospheric scattering channel, the coding pulses are broadened and the orthogonality of the codes is worsened. In truly asynchronous case, namely both the chips and the bits are asynchronous among each active user, the pulse broadening affects the system performance a lot. In this paper, we evaluate the performance of a 2D asynchronous hard-limiting wireless OCDMA system through atmospheric scattering channel. The probability density function of multiple access interference in truly asynchronous case is given. The bit error rate decreases as the ratio of the chip period to the root mean square delay spread increases and the channel limits the bit rate to different levels when the chip period varies.
International Nuclear Information System (INIS)
Kuehner, G.
1982-01-01
In the nucleus 208 Pb giant multipole resonances up to excitation energies of Esub(x) = 35 MeV were looked for by medium resolution inelastic electron scattering. Twelve spectra were taken up at incident energies of E 0 = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. On the base of this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forward angles a further weak excitation at Esub(x) approx.= 14.6 MeV appears which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is observed also in (α, α') experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also a Jsup(π) = 3 - character but has to be partly assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gets because of model predictions a ΔT = 1 assignment. (orig./HSI) [de
International Nuclear Information System (INIS)
Mayer, M.; Arstila, K.; Nordlund, K.; Edelmann, E.; Keinonen, J.
2006-01-01
Angular and energy distributions due to multiple small angle scattering were calculated with different models, namely from the analytical Szilagyi theory, the Monte-Carlo code MCERD in binary collision approximation and the molecular dynamics code MDRANGE, for 2 MeV 4 He in Au at backscattering geometry and for 20 MeV 127 I recoil analysis of carbon. The widths and detailed shapes of the distributions are compared, and reasons for deviations between the different models are discussed
A Path Loss Model for Non-Line-of-Sight Ultraviolet Multiple Scattering Channels
2010-01-01
scattering is self -governed, and the distances and angles for different scattering events are conditioned on previous quantities. Therefore, the arrival...solid angle of the receiver determined by the receiver area and distance rn. Note that no integration over rn is needed because it is a function of...www.eurasip.org). This year edition will take place in Barcelona, capital city of Catalonia (Spain), and will be jointly organized by the Centre Tecnològic de
A Path Loss Model for Non-Line-of-Sight Ultraviolet Multiple Scattering Channels
Directory of Open Access Journals (Sweden)
Sadler BrianM
2010-01-01
Full Text Available An ultraviolet (UV signal transmission undergoes rich scattering and strong absorption by atmospheric particulates. We develop a path loss model for a Non-Line-of-Sight (NLOS link. The model is built upon probability theory governing random migration of photons in free space, undergoing scattering, in terms of angular direction and distance. The model analytically captures the contributions of different scattering orders. Thus it relaxes the assumptions of single scattering theory and provides more realistic results. This allows us to assess the importance of high-order scattering, such as in a thick atmosphere environment, where short range NLOS UV communication is enhanced by hazy or foggy weather. By simulation, it is shown that the model coincides with a previously developed Monte Carlo model. Additional numerical examples are presented to demonstrate the effects of link geometry and atmospheric conditions. The results indicate the inherent tradeoffs in beamwidth, pointing angles, range, absorption, and scattering and so are valuable for NLOS communication system design.
Quasi elastic scattering of 600 MeV protons by alpha clusters in light and medium nuclei
International Nuclear Information System (INIS)
Landaud, G.; Devaux, A.; Delpierre, P.; Kahane, J.; Sene, R.; Yonnet, J.; Anne, R.
1977-06-01
Knockout of α-clusters from light and medium weight nuclei by 600 MeV protons has been investigated. The outgoing protons and α-particles were detected in coincidence; their momenta were measured with two large magnetic spectrometers with proportional wire chambers. Experimental methods used to work with a high beam rate and an efficient proton rejection in the α-arm are described. Separation energy spectra are given for 6 Li, 7 Li, 12 C, 24 Mg, 27 Al and 40 Ca nuclei. A peak is observed at an excited energy equal to zero, except for the 27 Al target
Schäfer, Sascha; Liang, Wenxi; Zewail, Ahmed H
2011-12-07
Recent studies in ultrafast electron crystallography (UEC) using a reflection diffraction geometry have enabled the investigation of a wide range of phenomena on the femtosecond and picosecond time scales. In all these studies, the analysis of the diffraction patterns and their temporal change after excitation was performed within the kinematical scattering theory. In this contribution, we address the question, to what extent dynamical scattering effects have to be included in order to obtain quantitative information about structural dynamics. We discuss different scattering regimes and provide diffraction maps that describe all essential features of scatterings and observables. The effects are quantified by dynamical scattering simulations and examined by direct comparison to the results of ultrafast electron diffraction experiments on an in situ prepared Ni(100) surface, for which structural dynamics can be well described by a two-temperature model. We also report calculations for graphite surfaces. The theoretical framework provided here allows for further UEC studies of surfaces especially at larger penetration depths and for those of heavy-atom materials. © 2011 American Institute of Physics
International Nuclear Information System (INIS)
Li Jiahua; Liu Jibing; Qi Chunchao; Chen Aixi
2006-01-01
We investigate the features of the spontaneous emission spectra in a coherently driven cold five-level atomic system by means of a radio frequency (rf) or microwave field driving a hyperfine transition within the ground state. It is shown that a few interesting phenomena such as spectral-line narrowing, spectral-line enhancement, spectral-line suppression, and spontaneous emission quenching can be realized by modulating the frequency and intensity of the rf-driving field in our system. In the dressed-state picture of the coupling and rf-driving fields, we find that this coherently driven atomic system has three close-lying levels so that multiple spontaneously generated coherence (SGC) arises. Our considered atomic model can be found in real atoms, such as rubidium or sodium, so a corresponding experiment can be done to observe the expected phenomena related to SGC reported by Fountoulakis et al. [Phys. Rev. A 73, 033811 (2006)], since no rigorous conditions are required
Allocation of police posts in a medium-sized city: a multiple criteria approach
Directory of Open Access Journals (Sweden)
Charles Miller Gois de Oliveira
2015-09-01
Full Text Available Changes in violent crime rates implies a need for strategies to protect the population. Public safety policies should be focused on preventive security, which has the potential to reduce crime rates. The allocation of the police observation posts contributes to an increase in safety. However, given limited resources, the number of observation units has reduced in most Brazilian cities. Therefore, efficient allocation of these resources is necessary to ensure rational use of security agents. Several aspects influence decisions related to where to install these units, complicating this process. The multiple criteria approach is appropriate in this type of decision-making process, because it allows the decision maker to generate and consolidate knowledge. The results indicate that the most suitable neighborhoods are those with higher rates of violence and greater social gaps. This work presents some benefits to the area of public security, since it formalizes tacit knowledge into explicit knowledge. The information contained in this study may be made available to other public administrators who need to make this kind of decision.
Quantum multiple scattering: Eigenmode expansion and its applications to proximity resonance
International Nuclear Information System (INIS)
Li Sheng; Heller, Eric J.
2003-01-01
We show that for a general system of N s-wave point scatterers, there are always N eigenmodes. These eigenmodes or eigenchannels play the same role as spherical harmonics for a spherically symmetric target--they give a phase shift only. In other words, the T matrix of the system is of rank N, and the eigenmodes are eigenvectors corresponding to nonzero eigenvalues of the T matrix. The eigenmode expansion approach can give insight to the total scattering cross section; the position, width, and superradiant or subradiant nature of resonance peaks; the unsymmetric Fano line shape of sharp proximity resonance peaks based on the high-energy tail of a broadband; and other properties. Off-resonant eigenmodes for identical proximate scatterers are approximately angular-momentum eigenstates
Analysis of pp scattering at the CERN ISR energies in the multiple Regge pole model
International Nuclear Information System (INIS)
Bugrij, A.I.; Kobylinsky, N.A.
1976-01-01
The simple Regge model is suggested for describing data on proton-proton elastic scattering at high energies. The simplest variant of the Regge model can be formulated as a sum of two pomerons, the first being a moving double pole and the second - a fixed simple pole. Comparison with known data is given. The model gives an infinite rise of the total cross section of pp-scattering. The differential cross section changes slowly with energy. The models of two pomerons reproduce many features of the geometric scaling, in particular, the shift of the dip and rise of scattering total cross section at the second maximum. The considered model is rather simple and is well consistent with experiment
Kobayashi, Satoru; Tanelli, Simone; Im, Eastwood
2005-01-01
Effects of multiple scattering on reflectivity are studied for millimeter wavelength weather radars. A time-independent vector theory, including up to second-order scattering, is derived for a single layer of hydrometeors of a uniform density and a uniform diameter. In this theory, spherical waves with a Gaussian antenna pattern are used to calculate ladder and cross terms in the analytical scattering theory. The former terms represent the conventional multiple scattering, while the latter terms cause backscattering enhancement in both the copolarized and cross-polarized components. As the optical thickness of the hydrometeor layer increases, the differences from the conventional plane wave theory become more significant, and essentially, the reflectivity of multiple scattering depends on the ratio of mean free path to radar footprint radius. These results must be taken into account when analyzing radar reflectivity for use in remote sensing.
Solving protein nanocrystals by cryo-EM diffraction: Multiple scattering artifacts
Energy Technology Data Exchange (ETDEWEB)
Subramanian, Ganesh [Department of Materials Science and Engineering, Arizona State University, Tempe, AZ (United States); Basu, Shibom [Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ (United States); Liu, Haiguang [Department of Physics, Arizona State University, Tempe, AZ 85287-1504 (United States); Zuo, Jian-Min [Department of Materials Science and Engineering, University of Illinois, Urbana, IL (United States); Spence, John C.H., E-mail: spence@asu.edu [Department of Physics, Arizona State University, Tempe, AZ 85287-1504 (United States)
2015-01-15
The maximum thickness permissible within the single-scattering approximation for the determination of the structure of perfectly ordered protein microcrystals by transmission electron diffraction is estimated for tetragonal hen-egg lysozyme protein crystals using several approaches. Multislice simulations are performed for many diffraction conditions and beam energies to determine the validity domain of the required single-scattering approximation and hence the limit on crystal thickness. The effects of erroneous experimental structure factor amplitudes on the charge density map for lysozyme are noted and their threshold limits calculated. The maximum thickness of lysozyme permissible under the single-scattering approximation is also estimated using R-factor analysis. Successful reconstruction of density maps is found to result mainly from the use of the phase information provided by modeling based on the protein data base through molecular replacement (MR), which dominates the effect of poor quality electron diffraction data at thicknesses larger than about 200 Å. For perfectly ordered protein nanocrystals, a maximum thickness of about 1000 Å is predicted at 200 keV if MR can be used, using R-factor analysis performed over a subset of the simulated diffracted beams. The effects of crystal bending, mosaicity (which has recently been directly imaged by cryo-EM) and secondary scattering are discussed. Structure-independent tests for single-scattering and new microfluidic methods for growing and sorting nanocrystals by size are reviewed. - Highlights: • Validity domain of single-scattering approximation for protein electron diffraction is assessed • Electron Diffraction for tetragonal hen-egg lysozyme is simulated using multislice. • Bias from the use of phase information in modeling by molecular replacement (MR) is evaluated. • We find an approximate upper thickness limit, if MR is used, of 100 nm. • A 35% error in structure factor magnitudes may be
Comparison of approximate methods for multiple scattering in high-energy collisions. II
International Nuclear Information System (INIS)
Nolan, A.M.; Tobocman, W.; Werby, M.F.
1976-01-01
The scattering in one dimension of a particle by a target of N like particles in a bound state has been studied. The exact result for the transmission probability has been compared with the predictions of the Glauber theory, the Watson optical potential model, and the adiabatic (or fixed scatterer) approximation. The approximate methods optical potential model is second best. The Watson method is found to work better when the kinematics suggested by Foldy and Walecka are used rather than that suggested by Watson, that is to say, when the two-body of the nucleon-nucleon reduced mass
Voit, Florian; Schäfer, Jan; Kienle, Alwin
2009-09-01
We present a methodology to compare results of classical radiative transfer theory against exact solutions of Maxwell theory for a high number of spheres. We calculated light propagation in a cubic scattering region (20 x 20 x 20 microm(3)) consisting of different concentrations of polystyrene spheres in water (diameter 2 microm) by an analytical solution of Maxwell theory and by a numerical solution of radiative transfer theory. The relative deviation of differential as well as total scattering cross sections obtained by both approaches was evaluated for each sphere concentration. For the considered case, we found that deviations due to radiative transfer theory remain small, even for concentrations up to ca. 20 vol. %.
Multiple refraction switches realized by stretching elastomeric scatterers in sonic crystals
Directory of Open Access Journals (Sweden)
Y. Huang
2015-02-01
Full Text Available The effect of out-of-plane pre-stretch on the 2D sonic crystal with stretchable elastomeric scatterers is explored. The hyperelastic scatterers are characterized by a compressible neo-Hookean model. The Dirichlet-to-Neumann (DtN map is adopted to obtain the band structure and equi-frequency contours. We focus on the first passband and find that a variety of switching functionalities for refraction behaviors can be realized in selected frequencies under a specific pre-stretch range. These refraction switches enable an active control of wave propagation and are applicable in advanced technologies where switchable and multifunctional sonic crystals are required.
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.
Czech Academy of Sciences Publication Activity Database
Woo, W.; Em, V.; Shin, E.; Mikula, Pavol; Ryukhtin, Vasyl
2015-01-01
Roč. 48, APR (2015), s. 350-356 ISSN 0021-8898 R&D Projects: GA ČR GB14-36566G; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : peak broadening * small-angle neutron scattering * neutron diffraction * magnetic domain Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.720, year: 2014
Penttilä, Antti; Väisänen, Timo; Markkanen, Johannes; Martikainen, Julia; Gritsevich, Maria; Muinonen, Karri
2017-10-01
We combine numerical tools to analyze the reflectance spectra of granular materials. Our motivation comes from the lack of tools when it comes to intimate mixing of materials and modeling space-weathering effects with nano- or micron-sized inclusions. The current practice is to apply a semi-physical models such as the Hapke models (e.g., Icarus 195, 2008). These are expressed in a closed form so that they are fast to apply. The problem is that the validity of the model is not guaranteed, and the derived properties related to particle scattering can be unrealistic (JQSRT 113, 2012).Our pipeline consists of individual scattering simulation codes and a main program that chains them together. The chain for analyzing a macroscopic target with space-weathered mineral would go as: (1) Scattering properties of small inclusions inside a host matrix are derived using exact Maxwell equation solvers. From the scattering properties, we use the so-called incoherent fields and Mueller matrices as input for the next step; (2) Scattering by a regolith grain is solved using a geometrical optics method with surface reflections, internal absorption, and internal diffuse scattering; (3) The radiative transfer simulation is executed inputting the regolith grains from the previous step as the scatterers in a macroscopic planar volume element.For the most realistic asteroid reflectance model, the chain would produce the properties of a planar surface element. Then, a shadowing simulation over the surface elements would be considered, and finally the asteroid phase function would be solved by integrating the bidirectional reflectance distribution function of the planar element over the object's realistic shape model.The tools in the proposed chain already exist, and practical task for us is to tie these together into an easy-to-use public pipeline. We plan to open the pipeline as a web-based open service a dedicated server, using Django application server and Python environment for the
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.
Marchenko imaging below an overburden with random scatterers
Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Vasconcelos, I.; Slob, E.C.
2014-01-01
Marchenko imaging is a new way to deal with internal multiple scattering in migration. It has been designed for layered media with smooth interfaces. Here we analyze the performance of the Marchenko scheme for a medium with many point scatterers. Although the conditions for Marchenko imaging are
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...... 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...
International Nuclear Information System (INIS)
Gagnon, J.S.; Fillion-Gourdeau, F.; Sangyong Jeong; RIKEN Research Center, Upton, NY
2006-01-01
We use the full multiple scattering expansion of the retarded self-energy to obtain the gain and loss rates present in the Kadanoff-Baym relativistic transport equation. The rates we obtain include processes with any number of particles. As a first approximation, we only consider central cuts in the self-energies, but otherwise our results are general. We specialize to the case of scalar field theory to compare with lowest order results. The main application of this work is relativistic transport theory of very dense systems, such as the quark-gluon plasma or the early universe, where multi-particle interactions are important. (author)
Wang, Kezhi; Wang, Tian; Chen, Yunfei; Alouini, Mohamed-Slim
2014-01-01
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.
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.
Revisit the spin-FET: Multiple reflection, inelastic scattering, and lateral size effects
Xu, Luting; Li, Xin-Qi; Sun, Qing-feng
2014-01-01
We revisit the spin-injected field effect transistor (spin-FET) by simulating a lattice model based on recursive lattice Green's function approach. In the one-dimensional case and coherent regime, the simulated results reveal noticeable differences from the celebrated Datta-Das model, which motivate thus an improved treatment and lead to analytic and generalized result. The simulation also allows us to address inelastic scattering (using B\\"uttiker's fictitious reservoir approach) and lateral...
International Nuclear Information System (INIS)
Torrini, M.
1983-01-01
The exponential nature of the translation matrix G of spherical free waves has been set forth in a previous paper.The explicit expression of the exponential form of the translation matrix is given here, once the eigenvectros and the eigenvalues of G have been found. In addition, the eigenproblem relative to the matrix which transforms outgoing waves scattered by a centre in a set of spherical free waves centered at a different point is solved
Multiple Scattering of Gamma Radiation in a Spherical Concrete Wall Room
Energy Technology Data Exchange (ETDEWEB)
Leimdoerfer, M
1962-12-15
The Monte Carlo method has been applied for the calculation of the energy flux of scattered gamma radiation in a spherical room surrounded by an infinitely thick spherical wall and with a point source at the centre. Source energies were I, 2, 4, 6, and 10 MeV. The main investigation was carried out at a room radius of 500 cm but, for the 1 MeV source, the influence of varying the room radius down to 1 cm was analysed. The results contain energy distributions of the first four successive reflection components at the centre of the room and at the wall surface, as well as spatial distributions of the successive energy flux components. The neglect of reflection contributions of order five and higher was estimated to introduce an error of less than 0. 2 % of the total scattered energy flux. An analytical approximation is shown to produce a useful and easily applicable method of predicting the amount of scattered radiation in a spherical room.
Multiple Scattering of Gamma Radiation in a Spherical Concrete Wall Room
International Nuclear Information System (INIS)
Leimdoerfer, M.
1962-12-01
The Monte Carlo method has been applied for the calculation of the energy flux of scattered gamma radiation in a spherical room surrounded by an infinitely thick spherical wall and with a point source at the centre. Source energies were I, 2, 4, 6, and 10 MeV. The main investigation was carried out at a room radius of 500 cm but, for the 1 MeV source, the influence of varying the room radius down to 1 cm was analysed. The results contain energy distributions of the first four successive reflection components at the centre of the room and at the wall surface, as well as spatial distributions of the successive energy flux components. The neglect of reflection contributions of order five and higher was estimated to introduce an error of less than 0. 2 % of the total scattered energy flux. An analytical approximation is shown to produce a useful and easily applicable method of predicting the amount of scattered radiation in a spherical room
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.)
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.
2017-01-10
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.
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
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.
Wang, Kezhi; Wang, Tian; Chen, Yunfei; Alouini, Mohamed-Slim
2015-01-01
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.
Studies on laser beam propagation and stimulated scattering in multiple beam experiments
International Nuclear Information System (INIS)
Labaune, C.; Lewis, K.; Bandulet, H.; Lewis, K.; Depierreux, S.; Huller, S.; Masson-Laborde, P.E.; Pesme, D.; Riazuelo, G.
2006-01-01
The propagation and stimulated scattering of intense laser beams interacting with underdense plasmas are two important issues for inertial confinement fusion (ICF). The purpose of this work was to perform experiments under well-controlled interaction conditions and confront them with numerical simulations to test the physics included in the codes. Experimental diagnostics include time and space resolved images of incident and SBS light and of SBS-ion acoustic activity. New numerical diagnostics, including similar constraints as the experimental ones and the treatment of the propagation of the light between the emitting area and the detectors, have been developed. Particular care was put to include realistic plasma density and velocity profiles, as well as laser pulse shape in the simulations. In the experiments presented in this paper, the interaction beam was used with a random phase plate (RPP) to produce a statistical distribution of speckles in the focal volume. Stimulated Brillouin Scattering (SBS) was described using a decomposition of the spatial scales which provides a predictive modeling of SBS in an expanding mm-scale plasma. Spatial and temporal behavior of the SBS-ion acoustic waves was found to be in good agreement with the experimental ones for two laser intensities. (authors)
International Nuclear Information System (INIS)
Friedrich, J.; Voegler, N.
1982-01-01
All available information on charge distributions of even-even nuclei is analysed systematically. For medium and heavy nuclei five general features of p(r) are investigated: (i) The extension for which we discuss several different definitions. The measured extension together with experimental binding energies allows a determination of nuclear compressibility within the framework of the droplet model, the resulting value being K = 165 +- 10 MeV. (ii) The surface thickness. Here too, several definitions are discussed. A close relationship between the surface thickness and binding energies is demonstrated. (iii) The average slope in the inner part of the nucleus. A method is formulated to separate this slope from the oscillations observed. All nuclei show a positive slope of comparable size. (iv) The oscillations on p(r). They are related to an abrupt breakdown in the form factor around q = 2.25 fm -1 . This effect seems to be closely related to the fact that p(r) is built up out of single particles, details however being unimportant. (v) The high-q components of the form factor are indicative for a scattering mechanism involving pairs of nucleons. (orig.)
Mann, Nishan; Hughes, Stephen
2018-02-01
We present the analytical and numerical details behind our recently published article [Phys. Rev. Lett. 118, 253901 (2017), 10.1103/PhysRevLett.118.253901], describing the impact of disorder-induced multiple scattering on counterpropagating solitons in photonic crystal waveguides. Unlike current nonlinear approaches using the coupled mode formalism, we account for the effects of intraunit cell multiple scattering. To solve the resulting system of coupled semilinear partial differential equations, we introduce a modified Crank-Nicolson-type norm-preserving implicit finite difference scheme inspired by the transfer matrix method. We provide estimates of the numerical dispersion characteristics of our scheme so that optimal step sizes can be chosen to either minimize numerical dispersion or to mimic the exact dispersion. We then show numerical results of a fundamental soliton propagating in the presence of multiple scattering to demonstrate that choosing a subunit cell spatial step size is critical in accurately capturing the effects of multiple scattering, and illustrate the stochastic nature of disorder by simulating soliton propagation in various instances of disordered photonic crystal waveguides. Our approach is easily extended to include a wide range of optical nonlinearities and is applicable to various photonic nanostructures where power propagation is bidirectional, either by choice, or as a result of multiple scattering.
International Nuclear Information System (INIS)
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 the 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 are 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. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
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.
Experimental study of single-particle inclusive hadron scattering and associated multiplicities
International Nuclear Information System (INIS)
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.
1982-01-01
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 π +- , K +- , 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< x<1.0 and p/sub T/<1.25 GeV/c. Additional data covering a more restricted range in x were also gathered at 70 GeV/c incident momentum. In this high-statistics experiment, the identification of both the incoming and outgoing charged hadrons were made with a total of eight Cerenkov counters. New and extensive single-particle inclusive data for charged-particle production in low-p/sub T/ hadronic fragmentation are presented. The average associated charged-particle multiplicity and pseudorapidity distributions are also given
International Nuclear Information System (INIS)
Lohmander, H.
1995-04-01
Charged particle and transverse energy flow for deep inelastic ep scattering at HERA have been investigated in the hadronic center of mass systems as a function of pseudorapidity η* in different W 2 and Q 2 intervals. In addition, the mean charged particle multiplicity ch > and the mean transverse energy * Τ > as a function of W 2 and Q 2 have been studied. The measurements were made in the kinematic region 85 2 2 . The ch > was found to increase with increasing W 2 at fixed Q 2 but did not show any significant dependence on Q 2 at fixed W 2 . The best description of the mean charged multiplicity is given by ch >=a+b·ln(W 2 /GeV 2 ) with a=-1.38±0.07 and b=0.93±0.05. The * Τ > increased both with increasing W 2 at fixed Q 2 and with increasing Q 2 at fixed W 2 . The mean transverse energy is described by * Τ >=a+b·ln(W 2 /GeV 2 )+c·ln (Q 2 /GeV 2 )GeV with a=-5.93±0.07, b=1.28±0.06 and c=0.69±0.02. Different QCD models have been compared with data. Only the Color Dipole Model, as implemented in the Monte Carlo program Ariadne, describes the data satisfactorily. 29 refs
International Nuclear Information System (INIS)
Zhang, X.; Gonis, A.; MacLaren, J.M.
1989-01-01
We present a new real-space multiple-scattering-theory method for the solution of the Schroedinger equation and the calculation of the electronic structure of solid materials with full or reduced symmetry. The method is based on the concept of semi-infinite periodicity (SIP), rather than translational invariance, and on the property of removal invariance of the scattering matrix of systems with SIP. This latter property allows one to replace the usual Brillouin-zone integrals in reciprocal space by a self-consistency equation for the t matrix, which is sufficient for the determination of the Green function and related properties. Because it is developed entirely in direct space, the method provides a unified treatment of the electronic structure of bulk materials, surfaces, interfaces and grain boundaries (coherent or incoherent), impurities of interstitial or substitutional kinds, and can be easily extended to treat concentrated, substitutionally disordered alloys. One of its advantages over methods based on Bloch's theorem and reciprocal space is the great simplicity of setting up and running the associated computer codes even for complex structures, and structures with reduced or no symmetry that lie outside the realm of applicability of conventional methods. We present the results of model calculations for one-dimensional and three-dimensional model systems as well as for three-dimensional realistic materials. Where appropriate, these results are compared with those obtained through conventional techniques, and give an indication of the method's flexibility and reliability. Our applications of this method to this point are discussed, and our plans for future development are presented
Kulinich, P; Krylov, V
2004-01-01
Novel String Banana Template Method (SBTM) for track reconstruction in difficult conditions is proposed and implemented for off-line analysis of relativistic heavy ion collision events. The main idea of the method is in use of features of ensembles of tracks selected by 3-fold coincidence. Two steps model of track is used: the first one - averaged over selected ensemble and the second - per event dependent. It takes into account Multiple Scattering (MS) for this particular track. SBTM relies on use of stored templates generated by precise Monte Carlo simulation, so it's more time efficient for the case of 2D spectrometer. All data required for track reconstruction in such difficult conditions could be prepared in convenient format for fast use. Its template based nature and the fact that the SBTM track model is actually very close to the hits implies that it can be implemented in a firmware processor. In this report a block diagram of firmware based pre-processor for track reconstruction in CMS-like Si tracke...
Polarized neutron scattering study of the multiple order parameter system NdB4
Metoki, N.; Yamauchi, H.; Matsuda, M.; Fernandez-Baca, J. A.; Watanuki, R.; Hagihala, M.
2018-05-01
Neutron polarization analysis has been carried out in order to clarify the magnetic structures of multiple order parameter f -electron system NdB4. We confirmed the noncollinear "all-in all-out" structure (Γ4) of the in-plane moment, which is in good agreement with our previous neutron powder diffraction study. We found that the magnetic moment along the c -axis mc showed diagonally antiferromagnetic structure (Γ10), inconsistent with previously reported "vortex" structure (Γ2). The microscopic mixture of these two structures with q⃗0=(0 ,0 ,0 ) appears in phase II and remains stable in phases III and IV, where an incommensurate modulation coexists. The unusual magnetic ordering is phenomenologically understood via Landau theory with the primary order parameter Γ4 coupled with higher-order secondary order parameter Γ10. The magnetic moments were estimated to be 1.8 ±0.2 and 0.2 ±0.05 μB at T =7.5 K for Γ4 and Γ10, respectively. We also found a long-period incommensurate modulation of the q⃗1=(0 ,0 ,1 /2 ) antiferromagnetic structure of mc with the propagation q⃗s 1=(0.14 ,0.14 ,0.1 ) and q⃗s 2=(0.2 ,0 ,0.1 ) in phase III and IV, respectively. The amplitude of sinusoidal modulation was about mc=1.0 ±0.2 μB at T =1.5 K. The local (0 ,0 ,1 /2 ) structure consists of in-plane ferromagnetic and out-of-plane antiferromagnetic coupling of mc, opposite to the coexisting Γ10. The mc of Γ10 is significantly enhanced up to 0.6 μB at T =1.5 K, which is accompanied by the incommensurate modulations. The Landau phenomenological approach indicates that the higher-order magnetic and/or multipole interactions based on the pseudoquartet f -electron state play important roles.
Medium energy probes and nuclear structure
International Nuclear Information System (INIS)
Ginocchio, J.N.
1984-01-01
In this paper we explore two topics. The first topic is the marriage of medium energy reaction theory with the interacting boson model of nuclei in such a way that the multiple scattering is summed to all orders. The second topic is an exactly solvable potential model which gives realistic shell model eigenfunctions which can be used to calculate static and transition nuclear densities. (orig./HSI)
Heavy quark energy loss in nuclear medium
International Nuclear Information System (INIS)
Zhang, Benr-Wei; Wang, Enke; Wang, Xin-Nian
2003-01-01
Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark
International Nuclear Information System (INIS)
Ando, K.; Bando, H.; Krenciglowa, E.M.
1978-01-01
A three-particle one-hole multiple scattering equation for the two-valence nucleon system is derived and used to give the 3p1h contribution to the Q-box. Full exchanges among the 3p1h intermediate configurations are incorporated and the energy dependence of the underlying reaction matrix is properly taken into account. The equation includes processes comparable in scope to a large scale [2p+3p1h] shell model but is embedded within the framework of the diagrammatic expansion for the effective interaction. Using an essentially 'exact', energy-dependent reaction matrix this formalism is applied to the mass-18 system. The roles of various correlations and proper energy dependence of the reaction matrix are closely examined. In comparison with previous calculations, the present results are significantly more attractive and give the experimental level ordering in both the Tsup(π) = 0 + and 1 + low-lying spectra. Low-lying particle-particle correlations are found to play a dominant role. (Auth.)
International Nuclear Information System (INIS)
Strandlie, A.; Wroldsen, J.
2006-01-01
If any of the probability densities involved in track fitting deviate from the Gaussian assumption, it is plausible that a non-linear estimator which better takes the actual shape of the distribution into account can do better. One such non-linear estimator is the Gaussian-sum filter, which is adequate if the distributions under consideration can be approximated by Gaussian mixtures. The main purpose of this paper is to present a Gaussian-sum filter for track fitting, based on a two-component approximation of the distribution of angular deflections due to multiple scattering. In a simulation study within a linear track model the Gaussian-sum filter is shown to be a competitive alternative to the Kalman filter. Scenarios at various momenta and with various maximum number of components in the Gaussian-sum filter are considered. Particularly at low momenta the Gaussian-sum filter yields a better estimate of the uncertainties than the Kalman filter, and it is also slightly more precise than the latter
International Nuclear Information System (INIS)
Ankowski, A.; Graczyk, K.; Nowak, J.; Sobczyk, J.; Antonello, M.; Cavanna, F.; Piano Mortari, G.; Segreto, E.; Aprili, P.; Arneodo, F.; Palamara, O.; Badertscher, A.; Ge, Y.; Laffranchi, M.; Messina, M.; Rubbia, A.; Baiboussinov, B.; Baldo Ceolin, M.; Centro, S.; Gibin, D.; Guglielmi, A.; Meng, G.; Pietropaolo, F.; Varanini, F.; Ventura, S.; Battistoni, G.; Muraro, S.; Sala, P.R.; 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.; Bueno, A.; Carmona, M.C.; Garcia-Gamez, D.; Lozano, J.; Martinez de la Ossa, A.; Melgarejo, A.J.; Navas, S.; Carbonara, F.; Cocco, A.G.; Di Cicco, A.; Ereditato, A.; Fiorillo, G.; Rossi, B.; Cennini, P.; Ferrari, A.; Cesana, A.; Terrani, M.; Cline, D.B.; Lisowski, B.; Matthey, C.; Otwinowski, S.; Seo, Y.; Wang, H.; Yang, X.; Cieslik, K.; Dabrowska, A.; Markiewicz, M.; Stefan, D.; Szarska, M.; Wachala, T.; Zalewska, A.; Gil-Botella, I.; Holeczek, J.; Kisiel, J.; Kielczewska, D.; Lagoda, J.; Posiadala, M.; Kozlowski, T.; Mijakowski, P.; Rondio, E.; Stepaniak, J.; Szeptycka, M.; Periale, L.; Picchi, P.; Polchlopek, W.; Sergiampietri, F.; Sulej, R.
2006-01-01
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 ν μ 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.)
Valier-Brasier, Tony; Conoir, Jean-Marc; Coulouvrat, François; Thomas, Jean-Louis
2015-10-01
Sound propagation in dilute suspensions of small spheres is studied using two models: a hydrodynamic model based on the coupled phase equations and an acoustic model based on the ECAH (ECAH: Epstein-Carhart-Allegra-Hawley) multiple scattering theory. The aim is to compare both models through the study of three fundamental kinds of particles: rigid particles, elastic spheres, and viscous droplets. The hydrodynamic model is based on a Rayleigh-Plesset-like equation generalized to elastic spheres and viscous droplets. The hydrodynamic forces for elastic spheres are introduced by analogy with those of droplets. The ECAH theory is also modified in order to take into account the velocity of rigid particles. Analytical calculations performed for long wavelength, low dilution, and weak absorption in the ambient fluid show that both models are strictly equivalent for the three kinds of particles studied. The analytical calculations show that dilatational and translational mechanisms are modeled in the same way by both models. The effective parameters of dilute suspensions are also calculated.
Virtual Singular Scattering of Electromagnetic Waves in Transformation Media Concept
Directory of Open Access Journals (Sweden)
M. Y. Barabanenkov
2012-07-01
Full Text Available If a scatterer and an observation point (receive both approach the so-called near field zone of a source of electromagnetic waves, the scattering process becomes singular one which is mathematically attributed to the spatial singularity of the free space Green function at the origin. Starting from less well known property of left-handed material slab to transfer the singularity of the free space Green function by implementing coordinate transformation, we present a phenomenon of virtual singular scattering of electromagnetic wave on an inhomogeneity located in the volume of left – handed material slab. Virtual singular scattering means that a scatterer is situated only virtually in the near field zone of a source, being, in fact, positioned in the far field zone. Such a situation is realized if a scatterer is embedded into a flat Veselago’s lens and approaches the lens’s inner focus because a slab of Veselago medium produces virtual sources inside and behind the slab and virtual scatterer (as a source of secondary waves from both slab sides. Considering a line-like dielectric scatterer we demonstrate that the scattering efficiency is proportional to product of singular quasistatic parts of two empty space Green functions that means a multiplicative quasistatic singularity of the Green function for a slab of inhomogeneous Veselago medium. We calculate a resonance value of the scattering amplitude in the regime similar to the known Mie resonance scattering.
Evaluation of a scattered radiation field in a cluster relevant for multiple-energy X-ray holography
International Nuclear Information System (INIS)
Fonda, L.
1996-09-01
We analyze theoretically a recent proposal of utilizing synchrotron radiation to generate an electromagnetic scattering field at a specific target atom inside a material sample. The direct wave coming from a wiggler interferes there with the waves scattered by the surrounding atoms. The suggestion is relevant for obtaining atomic holographic images. (author). 23 refs, 2 figs
International Nuclear Information System (INIS)
Martin, G.; Coca, M.; Capote, R.
1996-01-01
Using Monte Carlo method technique , a computer code which simulates the time of flight experiment to measure double differential cross section was developed. The correction factor for flux attenuation and multiple scattering, that make a deformation to the measured spectrum, were calculated. The energy dependence of the correction factor was determined and a comparison with other works is shown. Calculations for Fe 56 at two different scattering angles were made. We also reproduce the experiment performed at the Nuclear Analysis Laboratory for C 12 at 25 celsius degree and the calculated correction factor for the is measured is shown. We found a linear relation between the scatter size and the correction factor for flux attenuation
International Nuclear Information System (INIS)
Bando, H.; Krenciglowa, E.M.; Ando, K.
1979-01-01
Within the systematic framework of the double partition approach, the three-particle one-hole multiple scattering and Q-box formalisms are combined to give the valence-linked and connected energy-independent effective interaction. All low-lying [2p+3p1h] contributions to the mass-18 effective interaction are evaluated using an essentially exact energy-dependent reaction matrix based on the Reid SC potential. The low-lying one-body field of the core nucleus is treated consistently with the underlying reaction matrix G through particle- and hole-line self-energy insertions. Center-of-mass motion, folded diagrams and starting energy dependence are properly taken into account throughout. The low-lying [2p+3p1h] correlations are strongly damped by self-energy insertions. By incorporating only the folded diagram contributions with origins in the low-lying space, the net effect of all low-lying [2p+3p1h] correlations is to give back the bare-G plus second-order core-polarization spectra which are found to be in respectable agreement with the experimental spectra. However, including the full folded diagram contribution, which has additional contributions from the high-lying space through the energy dependence of G, leads to final spectra which deviate sizably from experiment. The present results are conclusive in the sense that the treatment is essentially exact for low-lying [2p+3p1h] correlations which originate from the high-lying two-particle correlations through the reaction matrix G. (Auth.)
Statistics of light deflection in a random two-phase medium
International Nuclear Information System (INIS)
Sviridov, A P
2007-01-01
The statistics of the angles of light deflection during its propagation in a random two-phase medium with randomly oriented phase interfaces is considered within the framework of geometrical optics. The probabilities of finding a randomly walking photon in different phases of the inhomogeneous medium are calculated. Analytic expressions are obtained for the scattering phase function and the scattering phase matrix which relates the Stokes vector of the incident light beam with the Stokes vectors of deflected beams. (special issue devoted to multiple radiation scattering in random media)
Directory of Open Access Journals (Sweden)
Martin Hilbert
2018-06-01
Full Text Available While the mobile phone is the world’s most popular media device, it is actually not one single medium, but is effectively used as a different medium by different user groups. The article characterizes polymodal differences in mobile apps usage among different user groups, including gender, education, occupation, screen size, and price. We monitored the complete app usage of 10,725 smartphone users for one month each (56 million sessions, recording almost 1 million hours. Our key contribution consists in developing and analyzing a theoretical framework to classify the over 16,000 apps used into five categories. Exploring nine research questions we provide a broad characterization by asking who, with which characteristics, uses which kinds of apps in what extensity and intensity? For example, it is not the young and high occupational grades that use the mobile phone as a human-to-machine computer (including gaming and artificial intelligence tools. Large screen size is related to extensive long sessions, while a small screen size is related to intensive frequent usage. The results go beyond providing ample empirical evidence for the inherently polymodal nature of the mobile phone, but also proposes a framework on how to deal with it analytically.
Energy Technology Data Exchange (ETDEWEB)
Aspelund, O; Gustafsson, B
1967-05-15
After an introductory discussion of various methods for correction of experimental left-right ratios for polarized multiple-scattering and finite-geometry effects necessary and sufficient formulas for consistent tracking of polarization effects in successive scattering orders are derived. The simplifying assumptions are then made that the scattering is purely elastic and nuclear, and that in the description of the kinematics of the arbitrary Scattering {mu}, only one triple-parameter - the so-called spin rotation parameter {beta}{sup ({mu})} - is required. Based upon these formulas a general discussion of the importance of the correct inclusion of polarization effects in any scattering order is presented. Special attention is then paid to the question of depolarization of an already polarized beam. Subsequently, the afore-mentioned formulas are incorporated in the comprehensive Monte Carlo program MULTPOL, which has been designed so as to correctly account for finite-geometry effects in the sense that both the scattering sample and the detectors (both having cylindrical shapes) are objects of finite dimensions located at finite distances from each other and from the source of polarized fast-neutrons. A special feature of MULTPOL is the application of the method of correlated sampling for reduction of the standard deviations .of the results of the simulated experiment. Typical data of performance of MULTPOL have been obtained by the application of this program to the correction of experimental polarization data observed in n + '{sup 12}C elastic scattering between 1 and 2 MeV. Finally, in the concluding remarks the possible modification of MULTPOL to other experimental geometries is briefly discussed.
International Nuclear Information System (INIS)
Singh, Tejbir; Singh, Parjit S
2011-01-01
The pulse height spectra for different thicknesses of portland cement in the reflected geometry has been recorded with the help of a NaI(Tl) scintillator detector and 2 K MCA card using different gamma-ray sources such as Hg 203 (279 keV), Cs 137 (662 keV) and Co 60 (1173 and 1332 keV). It has been observed that the multiple scatter peak for portland cement appears at 110 (±7) keV in all the spectra irrespective of different incident photon energies in the range 279-1332 keV from different gamma-ray sources. Further, the variation in the intensity of the multiple scatter peak with the thickness of portland cement in the backward semi-cylinders has been investigated.
International Nuclear Information System (INIS)
Bando, H.; Krenciglowa, E.M.
1976-01-01
The role of 2p1h correlations in 17 O is studied within a multiple-scattering formalism. An accurate, energy-dependent reaction matrix with orthogonalized plane-wave intermediate states is used to assess the relative importance of particle-particle and particle-hole correlations in the 17 O energies. The effect of energy dependence of the reaction matrix is closely examined. (Auth.)
Al-Qazwini, Zaineb A. T.; Abdullah, Mohamad K.; Mokhtar, Makhfudzah B.
2009-01-01
We measure the stimulated Raman scattering (SRS)-induced tilt in spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) systems as a function of system main parameters (transmission distance, power per chip, and number of users) via computer simulations. The results show that SRS-induced tilt significantly increases as transmission distance, power per chip, or number of users grows.
International Nuclear Information System (INIS)
Kuehner, E.G.F.
1982-01-01
In the nucleus 208 Pb giant multipole resonances were looked for by inelastic electron scattering up to excitation energies of Esub(x) = 35 MeV. Twelve spectra were taken up at incident energies of Esub(o) = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. Basing on this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as a superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forwards angles a further weak excitation appears at Esub(x) approx.= 14.6 MeV which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is also observed in (α,α') scattering experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also Jsup(π) = 3 - character but has partly to be assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gels because of model predictions a ΔT = 1 assignment. (orig./HSI) [de
Marassi, Valentina; Casolari, Sonia; Roda, Barbara; Zattoni, Andrea; Reschiglian, Pierluigi; Panzavolta, Silvia; Tofail, Syed A M; Ortelli, Simona; Delpivo, Camilla; Blosi, Magda; Costa, Anna Luisa
2015-03-15
Due to the increased use of silver nanoparticles in industrial scale manufacturing, consumer products and nanomedicine reliable measurements of properties such as the size, shape and distribution of these nano particles in aqueous medium is critical. These properties indeed affect both functional properties and biological impacts especially in quantifying associated risks and identifying suitable risk-mediation strategies. The feasibility of on-line coupling of a fractionation technique such as hollow-fiber flow field flow fractionation (HF5) with a light scattering technique such as MALS (multi-angle light scattering) is investigated here for this purpose. Data obtained from such a fractionation technique and its combination thereof with MALS have been compared with those from more conventional but often complementary techniques e.g. transmission electron microscopy, dynamic light scattering, atomic absorption spectroscopy, and X-ray fluorescence. The combination of fractionation and multi angle light scattering techniques have been found to offer an ideal, hyphenated methodology for a simultaneous size-separation and characterization of silver nanoparticles. The hydrodynamic radii determined by fractionation techniques can be conveniently correlated to the mean average diameters determined by multi angle light scattering and reliable information on particle morphology in aqueous dispersion has been obtained. The ability to separate silver (Ag(+)) ions from silver nanoparticles (AgNPs) via membrane filtration during size analysis is an added advantage in obtaining quantitative insights to its risk potential. Most importantly, the methodology developed in this article can potentially be extended to similar characterization of metal-based nanoparticles when studying their functional effectiveness and hazard potential. Copyright © 2014 Elsevier B.V. All rights reserved.
Finite-difference modelling of anisotropic wave scattering in discrete ...
Indian Academy of Sciences (India)
2
cells containing equivalent anisotropic medium by the use of the linear slip equivalent model. Our. 16 results show ...... frequency regression predicted by equation (21) can be distorted by the effects of multiple scattering. 337 ..... other seismic attributes, at least for the relatively simple geometries of subsurface structure. 449.
Energy Technology Data Exchange (ETDEWEB)
Anne, R [CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Service d' Entretien et de Developpement des Appareils de Physique; Delpierre, P; Kahane, J; Sene, R [College de France, 75 - Paris. Lab. de Physique Corpusculaire; Devaux, A; Landaud, G [Clermont-Ferrand Univ., 63 (France); Yonnet, J [Caen Univ., 14 (France). Lab. de Physique Corpusculaire
1975-01-01
Alpha knock out from light and medium nuclei up to /sup 40/Ca was investigated. Preliminary values of the differential cross sections are given for /sup 6/Li and /sup 12/C nuclei. The p(R) recoil momentum distributions show a maximum at p(R)=0.
Zhang, G. L.; Zhang, G. X.; Lin, C. J.; Lubian, J.; Rangel, J.; Paes, B.; Ferreira, J. L.; Zhang, H. Q.; Qu, W. W.; Jia, H. M.; Yang, L.; Ma, N. R.; Sun, L. J.; Wang, D. X.; Zheng, L.; Liu, X. X.; Chu, X. T.; Yang, J. C.; Wang, J. S.; Xu, S. W.; Ma, P.; Ma, J. B.; Jin, S. L.; Bai, Z.; Huang, M. R.; Zang, H. L.; Yang, B.; Liu, Y.
2018-04-01
The elastic scattering angular distributions were measured for 50- and 59-MeV 17F radioactive ion beam on a 89Y target. The aim of this work is to study the effect of the breakup of the proton halo projectile on the elastic scattering angular distribution. The experimental data were analyzed by means of the optical model with the double-folding São Paulo potential for both real and imaginary parts. The theoretical calculations reproduced the experimental data reasonably well. It is shown that the method of the data analysis is correct. In order to clarify the difference observed at large angles for the 59-MeV incident energy data, Continuum-Discretized Coupled-Channels (CDCC) calculations were performed to consider the breakup coupling effect. It is found that the experimental data show the Coulomb rainbow peak and that the effect of the coupling to the continuum states is not very significant, producing only a small hindrance of the Coulomb rainbow peak and a very small enhancement of the elastic scattering angular distribution at backward angles, suggesting that the multipole response of the neutron halo projectiles is stronger than that of the proton halo systems.
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
International Nuclear Information System (INIS)
Dedonder, J.-P.
1979-01-01
This work is devoted to the study of elastic hadron nucleus scattering. At first, an asymptotic evaluation leads to a closed, analytic expression of the eikonal amplitude. This approximate expression displays the role and the influence of the nuclear paremeters in, e.g., p-nucleus scattering around 1 GeV. Pion-nucleus scattering around the 3-3 resonance is then studied. A 3 body model calculation (pion, bound nucleon and residual nucleus represented by a potential) allows to study the importance of binding effects in this problem dominated by the strong energy dependence of the elementary amplitude. The last part is devoted to the construction in momentum space of a realistic optical potential and its comparison with experimental data. The scalling of π + and π - on neighbouring isotopes should allow the measure of the differences between the proton and neutron distributions in nuclei [fr
Tan, Shurun
The objective of my research is two-fold: to study wave scattering phenomena in dense volumetric random media and in periodic wave functional materials. For the first part, the goal is to use the microwave remote sensing technique to monitor water resources and global climate change. Towards this goal, I study the microwave scattering behavior of snow and ice sheet. For snowpack scattering, I have extended the traditional dense media radiative transfer (DMRT) approach to include cyclical corrections that give rise to backscattering enhancements, enabling the theory to model combined active and passive observations of snowpack using the same set of physical parameters. Besides DMRT, a fully coherent approach is also developed by solving Maxwell's equations directly over the entire snowpack including a bottom half space. This revolutionary new approach produces consistent scattering and emission results, and demonstrates backscattering enhancements and coherent layer effects. The birefringence in anisotropic snow layers is also analyzed by numerically solving Maxwell's equation directly. The effects of rapid density fluctuations in polar ice sheet emission in the 0.5˜2.0 GHz spectrum are examined using both fully coherent and partially coherent layered media emission theories that agree with each other and distinct from incoherent approaches. For the second part, the goal is to develop integral equation based methods to solve wave scattering in periodic structures such as photonic crystals and metamaterials that can be used for broadband simulations. Set upon the concept of modal expansion of the periodic Green's function, we have developed the method of broadband Green's function with low wavenumber extraction (BBGFL), where a low wavenumber component is extracted and results a non-singular and fast-converging remaining part with simple wavenumber dependence. We've applied the technique to simulate band diagrams and modal solutions of periodic structures, and to
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.
Hesford, Andrew J; Astheimer, Jeffrey P; Greengard, Leslie F; Waag, Robert C
2010-02-01
A multiple-scattering approach is presented to compute the solution of the Helmholtz equation when a number of spherical scatterers are nested in the interior of an acoustically large enclosing sphere. The solution is represented in terms of partial-wave expansions, and a linear system of equations is derived to enforce continuity of pressure and normal particle velocity across all material interfaces. This approach yields high-order accuracy and avoids some of the difficulties encountered when using integral equations that apply to surfaces of arbitrary shape. Calculations are accelerated by using diagonal translation operators to compute the interactions between spheres when the operators are numerically stable. Numerical results are presented to demonstrate the accuracy and efficiency of the method.
International Nuclear Information System (INIS)
Bhattacharya, S.
1989-01-01
The role of the leading particles in high energy scattering phenomena has assumed much importance in recent times but it has not been duly considered in some theoretical studies. This oversight is pointed out, and some other shortcomings and insufficiencies of most of the contemporary theoretical studies not only from considerations of the leading particle effect (LPE) but also from some other viewpoints are mentio ned. A revised comparative study on the behaviour of the average multiplicity by taking into account some of the competing theoretical models and the influence of the leading particle effect on them is also presented. (author). 33 refs
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)
International Nuclear Information System (INIS)
Sun Zhihu; Wei Shiqiang; Kolobov, A.V.; Oyanagi, H.; Brunner, K.
2005-01-01
Multiple-scattering extended x-ray absorption fine structure (MS-EXAFS) has been used to investigate the local structures around Ge atoms in self-assembled Ge-Si quantum dots (QDs) grown on Si(001) substrate. The MS effect of Ge QDs is dominated by the scattering path Ge 0 →B 1 →B 2 →Ge 0 (DS2), which contributes a signal destructively interfering with that of the second shell single-scattering path (SS2). MS-EXAFS analysis reveals that the degree of Ge-Si intermixing for Ge-Si QDs strongly depends on the temperature at which the silicon cap layer is overgrown. It is found that the interatomic distances (R Ge-Ge and R Ge-Si ) within the third nearest-neighbor shells in Ge-Si QDs indicate the compressively strained nature of QDs. The present study demonstrates that the MS-EXAFS provides detailed information on the QDs strain and the Ge-Si mixing beyond the nearest neighbors
Iguchi, Toshio; Meneghini, Robert
1993-01-01
Air-borne radar measurements of thunderstorms were made as part of the CaPE (Convection and Precipitation/Electrification) experiment in Florida in July 1991. The radar has two channels, X-band (10 GHz) and Ka-band (34.5 GHz), and is capable of measuring cross-polarized returns as well as co-polarized returns. In stratiform rain, the cross-polarized components can be observed only at the bright band region and from the surface reflection. The linear depolarization ratios (LDR's) measured at X-band and Ka-band at the bright band are nearly equal. In convective rain, however, the LDR in Ka-band often exceeds the X-band LDR by several dB, and sometimes by more than 10 dB, reaching LDR values of up to -5 dB over heavy convective rain. For randomly oriented hydrometeors, such high LDR values cannot be explained by single scattering from non-spherical scattering particles alone. Because the LDR by single backscatter depends weakly on the wavelength, the difference between the Ka-band and X-band LDR's suggests that multiple scattering effects prevail in the Ka-band LDR. In order to test this inference, the magnitude of the cross-polarized component created by double scattering was calculated using the parameters of the airborne radar, which for both frequencies has beamwidths of 5.1 degrees and pulse widths of 0.5 microsecond. Uniform rain beyond the range of 3 km is assumed.
Martikainen, Julia; Penttilä, Antti; Gritsevich, Maria; Muinonen, Karri
2017-10-01
Asteroids have remained mostly the same for the past 4.5 billion years, and provide us information on the origin, evolution and current state of the Solar System. Asteroids and meteorites can be linked by matching their respective reflectance spectra. This is difficult, because spectral features depend strongly on the surface properties, and meteorite surfaces are free of regolith dust present in asteroids. Furthermore, asteroid surfaces experience space weathering which affects their spectral features.We present a novel simulation framework for assessing the spectral properties of meteorites and asteroids and matching their reflectance spectra. The simulations are carried out by utilizing a light-scattering code that takes inhomogeneous waves into account and simulates light scattering by Gaussian-random-sphere particles large compared to the wavelength of the incident light. The code uses incoherent input and computes phase matrices by utilizing incoherent scattering matrices. Reflectance spectra are modeled by combining olivine, pyroxene, and iron, the most common materials that dominate the spectral features of asteroids and meteorites. Space weathering is taken into account by adding nanoiron into the modeled asteroid spectrum. The complex refractive indices needed for the simulations are obtained from existing databases, or derived using an optimization that utilizes our ray-optics code and the measured spectrum of the material.We demonstrate our approach by applying it to the reflectance spectrum of (4) Vesta and the reflectance spectrum of the Johnstown meteorite measured with the University of Helsinki integrating-sphere UV-Vis-NIR spectrometer.Acknowledgments. The research is funded by the ERC Advanced Grant No. 320773 (SAEMPL).
Study of multiple hard-scatter processes from different p p interactions in the same ATLAS event
The ATLAS collaboration
2018-01-01
Given the large integrated luminosity and the large average pileup in the 2017 ATLAS dataset, the probability of having two leptonically decaying Z bosons originating from separate $pp$ interactions in the same LHC bunch crossing becomes non-negligible. Such events are searched for and the number observed compared with the expectation. These types of events (also for the case involving other hard scatter processes, such as W, photon or top quark production, in the same event) may cause additional backgrounds for particular physics analyses, and therefore this background must be accounted for when relevant.
Analysis of the characteristics of a two-fiber sensor for monitorship of a turbid medium
International Nuclear Information System (INIS)
Zaccanti, G.; Bruscaglioni, P.; Luzi, G.
1987-01-01
Certain characteristics of a two-fiber sensor device, of the type proposed by Papa et al. for sea water turbidity monitorship, are examined. The extension of medium from which most of the received backscattered power originates is investigated, together with possible effects of multiple scattering on the received power
International Nuclear Information System (INIS)
Singh, Charanjeet; Sidhu, Gurdeep S.; Kumar, Ashok; Singh, Tejbir; Singh, Parjit S.; Mudahar, Gurmel S.
2005-01-01
The transmitted photon spectra of a point gamma-ray source of 60 Co have been measured through the longitudinal and transverse dimensions of a soil medium. The simultaneous effect of longitudinal and transverse thicknesses has been studied on the intensity of an appeared multiple-scatter peak in the soft part of the spectrum. The intensity of peak decreases exponentially with the increase of longitudinal thickness of soil medium whereas a reversal of the trend of multiple-scatter peak intensity with the transverse thickness observed as longitudinal dimension increases
International Nuclear Information System (INIS)
Kawano, Shinji; Fukui, Susumu; Moriai, Atsushi; Ohtomo, Akitoshi; Ichimura, Shigeki; Onodera, Akifumi; Amita, F.; Katano, Susumu
1998-01-01
We have developed unique system available for controlling sample environment during the neutron scattering experiments. The system can simultaneously generate triple extreme conditions of low temperature, high magnetic field and high pressure. The system consists of: (i) a liquid-helium cryostat variable for sample temperature from 1.7 K to 200 K, (ii) a superconducting magnet providing a vertical field up to ±5 T with an antisymmetric split-coil geometry for polarized-beam experiments, and (iii) a non-magnetic piston-cylinder high-pressure cell designed with the aim of generating hydrostatic pressure up to 2.5 GPa. In the presentation, we will report the outline of the system and some results of performance tests at KURRI and JRR-3M of JAERI. (author)
Forward scattering of polarized light from a turbid slab: theory and Monte Carlo simulations.
Otsuki, Soichi
2016-12-20
It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in turbid slab media. Monte Carlo simulations generate a reduced effective Mueller matrix for forward scattering, which satisfies reciprocity and mirror symmetry, but satisfies only reciprocity if the medium contains chiral components. The scattering matrix was factorized by using the Lu-Chipman polar decomposition, which affords the polarization parameters as a function of the radial distance from the center. The depolarization coefficients decrease with increasing distance, whereas the scattering-induced linear diattenuation and retardance become larger in the middle-distance range. The optical rotation for a chiral medium increases with increasing distance.
International Nuclear Information System (INIS)
Marinyuk, V V; Sheberstov, S V
2017-01-01
We calculate the total transmission coefficient (transmittance) of a disordered medium with large (compared to the light wavelength) inhomogeneities. To model highly forward scattering in the medium we take advantage of the Gegenbauer kernel phase function. In a subdiffusion thickness range, the transmittance is shown to be sensitive to the specific form of the single-scattering phase function. The effect reveals itself at grazing angles of incidence and originates from small-angle multiple scattering of light. Our results are in a good agreement with numerical solutions to the radiative transfer equation. (paper)
1984-05-29
radial distribution and inverse transform of this range. The region commonly used for the inverse transform usually corresponds to the first or second...r-space and comparing it with the corresponding model function. Figure 5 shows the filtered spectra (k weighting), where the pe. 48 allowed inverse ... transform range was successively increased from the radial distance corresponding to the first shell to all the first four shells. There are no multiple
Energy Technology Data Exchange (ETDEWEB)
Cox, A.J.; Warner, P.C.; Findlay, D.J.S.; Cookson, J.A. (eds.)
1986-06-01
Future fusion reactors will use lithium as a blanket material in order to breed tritium. Knowledge of the gamma ray production cross-sections associated with 14 MeV neutron interactions in lithium are therefore important for local heating and biological shielding calculations and neutron energy degradation studies. In the present work, the differential cross-sections have been measured for the production of 0.478 MeV gamma rays following the inelastic scattering of 14 MeV neutrons in large samples of LiF. The neutrons were produced using the /sup 3/H(d,n) /sup 4/He reaction, the deuterons being accelerated by a 150 kV SAMES type accelerator. In order to reduce the background level, the gamma ray signal was gated using a time-of-flight technique based on the alpha particle associated with neutron production. The gamma ray detector was a 3 x 3 inch NaI(T1) scintillator coupled to a 56AVP photomultiplier.
International Nuclear Information System (INIS)
Ziyu Wu; Paris, E.; Langenhorst, F.; Seifert, F.
2002-01-01
The O K-edge spectra of a series of Ti-bearing compounds with Ti in diffrent structural and chemical environments have been measured using electron energy-loss spectroscopy and analyzed using ab initio full multiple-scattering (MS) calculations. The near-edge structures arise mainly from covalency by direct and/or indirect interaction between O and metal atoms and between O and Si atoms. The coordination number of the cation and the site symmetry also influence the spectral shape and structures. Using different size clusters around the excited atom in the full MS simulation, it is possible to interpret and assign the features present in the spectra of each compund to its specific atomic arrangement and electronic structure. (au)
Microscopic optical potential at medium energies
International Nuclear Information System (INIS)
Malecki, A.
1979-01-01
The problems concerning a microscopic optical model for the elastic nuclear collisions at medium energies are discussed. We describe the method for constructing the optical potential which makes use of the particular properties of quantum scattering in the eikonal limit. The resulting potential is expressed in terms of the nuclear wave functions and the nucleon-nucleon scattering amplitudes. This potential has a dynamic character since by including the effects of multiple scattering it allows for the possibility of intermediate excitations of the projectile and target nuclei. The use of the potential in the exact wave equation accounts for the most important mechanisms present in the collisions between composite particles. The microscopic optical model was successfully applied in the analysis of elastic scattering of protons and α-particles on atomic nuclei in the energy range of 300-1000 MeV/nucleon. The dynamic optical potential in this case represents a considerable improvement over the eikonal Glauber model and the static optical potential of Watson. The possibilities to extend the microscopic description of the proton-nucleus interaction by considering the spin dependence of the elementary amplitude and the Majorana exchange effects were investigated. (author)
Medium modification of fragmentation functions
International Nuclear Information System (INIS)
Nezza, Pasquale Di
2007-01-01
Deep Inelastic Scattering is the cleanest process to investigate the space-time evolution of the hadronization. This was studied by the influence of the nuclear medium on lepto-production of hadrons at the Hermes experiment at DESY in semi-inclusive DIS of 27.6 GeV positrons off deuterium, nitrogen, krypton and xenon targets. The differential multiplicity for heavy targets relative to that of deuterium has been measured for the first time for various identified hadrons (φ + , φ - , φ 0 , k + , k - , p and anti-p) as a function of the virtual photon energy ?, the fraction z of this energy transferred to the hadron, and the hadron transverse momentum squared p 2 t . The distribution of the hadron transverse momentum is broadened towards high p 2 t in the nuclear medium, in a manner resembling the Cronin effect observed in collisions of heavy ions and protons with nuclei. The pt -broadening results give also important information about the pre-hadron formation time. Moreover, by studying the hadron attenuation of the leading and sub-leading hadrons, we report, for the first time, the possibility to better understand the hadron absorption and the energy loss contributions to the attenuation mechanism. (Author)
De Wolf, E.A.
2002-01-01
We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken-x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using the saturation model of Golec-Biernat and Wusthoff as an example, a simple explanation of geometrical scaling is presented. The relation between the QCD anomalous multiplicity dimension and the Pomeron intercept is discussed.
International Nuclear Information System (INIS)
Wolf, E.A. de
2002-01-01
We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken - x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using the saturation model of Golec-Biernat and Wuesthoff as an example, a simple explanation of geometrical scaling is presented. The relation between the QCD anomalous multiplicity dimension and the Pomeron intercept is discussed. (author)
Medium range energy proton nuclear scattering radiography
International Nuclear Information System (INIS)
Duchazeaubeneix, J.C.
1982-02-01
This thesis is concerned with a new application of the strong nuclear interaction aiming to radiographic analysis. In this work, some physical processes have been analyzed with detail; these processes play a fundamental role in method quality and limitations; they have been detailed to facilitate comprehension to scientists who are not nuclear physicists. To better appreciate specific qualities of the RDN (Radiography par Diffusion Nucleaire), a chapter reviews strong nuclear interaction properties. Then, the experimental device is described, processing and acquisition system. Spatial resolution and sensitivity limits are studied. Results are presented [fr
Létourneau, Pierre-David
2016-09-19
We present a wideband fast algorithm capable of accurately computing the full numerical solution of the problem of acoustic scattering of waves by multiple finite-sized bodies such as spherical scatterers in three dimensions. By full solution, we mean that no assumption (e.g. Rayleigh scattering, geometrical optics, weak scattering, Born single scattering, etc.) is necessary regarding the properties of the scatterers, their distribution or the background medium. The algorithm is also fast in the sense that it scales linearly with the number of unknowns. We use this algorithm to study the phenomenon of super-resolution in time-reversal refocusing in highly-scattering media recently observed experimentally (Lemoult et al., 2011), and provide numerical arguments towards the fact that such a phenomenon can be explained through a homogenization theory.
LIGHT SCATTERING BY FRACTAL DUST AGGREGATES. I. ANGULAR DEPENDENCE OF SCATTERING
Energy Technology Data Exchange (ETDEWEB)
Tazaki, Ryo [Department of Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Tanaka, Hidekazu [Astronomical Institute, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Okuzumi, Satoshi; Nomura, Hideko [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Kataoka, Akimasa, E-mail: rtazaki@kusastro.kyoto-u.ac.jp [Institute for Theoretical Astrophysics, Heidelberg University, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany)
2016-06-01
In protoplanetary disks, micron-sized dust grains coagulate to form highly porous dust aggregates. Because the optical properties of these aggregates are not completely understood, it is important to investigate how porous dust aggregates scatter light. In this study, the light scattering properties of porous dust aggregates were calculated using a rigorous method, the T -matrix method, and the results were then compared with those obtained using the Rayleigh–Gans–Debye (RGD) theory and Mie theory with the effective medium approximation (EMT). The RGD theory is applicable to moderately large aggregates made of nearly transparent monomers. This study considered two types of porous dust aggregates—ballistic cluster–cluster agglomerates (BCCAs) and ballistic particle–cluster agglomerates. First, the angular dependence of the scattered intensity was shown to reflect the hierarchical structure of dust aggregates; the large-scale structure of the aggregates is responsible for the intensity at small scattering angles, and their small-scale structure determines the intensity at large scattering angles. Second, it was determined that the EMT underestimates the backward scattering intensity by multiple orders of magnitude, especially in BCCAs, because the EMT averages the structure within the size of the aggregates. It was concluded that the RGD theory is a very useful method for calculating the optical properties of BCCAs.
Energy Technology Data Exchange (ETDEWEB)
Bluet, J C [Commissariat a l' Energie Atomique, Cadarache (France)
1966-02-01
Three problems of multiple scattering arising from neutron cross sections experiments, are reported here. The common hypothesis are: - Elastic scattering is the only possible process - Angular distributions are isotropic - Losses of particle energy are negligible in successive collisions. In the three cases practical results, corresponding to actual experiments are given. Moreover the results are shown in more general way, using dimensionless variable such as the ratio of geometrical dimensions to neutron mean free path. The FORTRAN codes are given together with to the corresponding flow charts, and lexicons of symbols. First problem: Measurement of sodium capture cross-section. A sodium sample of given geometry is submitted to a neutron flux. Induced activity is then measured by means of a sodium iodide cristal. The distribution of active nuclei in the sample, and the counter efficiency are calculated by Monte-Carlo method taking multiple scattering into account. Second problem: absolute measurement of a neutron flux using a glass scintillator. The scintillator is a use of lithium 6 loaded glass, submitted to neutron flux perpendicular to its plane faces. If the glass thickness is not negligible compared with scattering mean free path {lambda}, the mean path e' of neutrons in the glass is different from the thickness. Monte-Carlo calculation are made to compute this path and a relative correction to efficiency equal to (e' - e)/e. Third problem: study of a neutron collimator. A neutron detector is placed at the bottom of a cylinder surrounded with water. A neutron source is placed on the cylinder axis, in front of the water shield. The number of neutron tracks going directly and indirectly through the water from the source to the detector are counted. (author) [French] On traite dans ce rapport de trois problemes avec les hypotheses communes suivantes: 1.- Le seul processus de collision possible est la diffusion electrique. 2.- La distribution angulaire est
Energy Technology Data Exchange (ETDEWEB)
Boujamaa, R. [STMicroelectronics, 850, rue Jean Monnet, 38926 Crolles (France); CEA-LETI, MINATEC Campus, F38054 Grenoble (France); Laboratoire des Matériaux et du Génie Physique, CNRS, Grenoble INP, 3 parvis L. Néel, BP 257, 38016 Grenoble (France); Martinez, E.; Pierre, F.; Renault, O. [CEA-LETI, MINATEC Campus, F38054 Grenoble (France); Detlefs, B.; Zegenhagen, J. [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38000 Grenoble (France); Baudot, S. [STMicroelectronics, 850, rue Jean Monnet, 38926 Crolles (France); Gros-Jean, M., E-mail: Mickael.Gros-Jean@st.com [STMicroelectronics, 850, rue Jean Monnet, 38926 Crolles (France); Bertin, F. [STMicroelectronics, 850, rue Jean Monnet, 38926 Crolles (France); Dubourdieu, C., E-mail: Catherine.Dubourdieu@ec-lyon.fr [Institut des Nanotechnologies de Lyon, CNRS, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France)
2015-04-30
Highlights: • Precise La depth distribution in gate stacks before and after annealing by MEIS. • Analysis by HAXPES of the buried high K/SiO{sub 2} interface without removing TiN gate. • Formation of La-silicate at the HfSiON/SiON interface. • Internal electrical field induced at the HfSiON/SiON interface by the La diffusion. • Increase of electric field strength with initial LaO{sub x} thickness. - Abstract: In this paper, we report the effect of high temperature annealing on the chemical and electronic structure of technologically relevant TiN/LaO{sub x}/HfSiON/SiON/Si gate stacks. Using medium energy ion scattering from the backside of the samples, a non-destructive compositional depth profile of La has been obtained, revealing the lanthanum diffusion in the SiON interface layer upon annealing. To complement this analysis, hard X-ray photoelectron spectroscopy with synchrotron radiation has been performed to investigate the chemical and electronic structure of the gate stacks. The results show clear changes in the Hf and Ti core level energy positions with respect to Si bulk, with changes in the thickness of the LaO{sub x} capping layer. We infer that La diffusion generates an internal electrical field at the La-silicate interface between HfSiON and SiON, and that its strength increases with the increase of LaO{sub x} thickness. These findings support the band alignment model based on a La-induced interfacial dipole.
Energy Technology Data Exchange (ETDEWEB)
Lohmander, H
1995-04-01
Charged particle and transverse energy flow for deep inelastic ep scattering at HERA have been investigated in the hadronic center of mass systems as a function of pseudorapidity {eta}* in different W{sup 2} and Q{sup 2} intervals. In addition, the mean charged particle multiplicity
Cui, P. X.; Lian, F. L.; Wang, Y.; Wen, Yi; Chu, W. S.; Zhao, H. F.; Zhang, S.; Li, J.; Lin, D. H.; Wu, Z. Y.
2014-02-01
Prion-related protein (PrP), a cell-surface copper-binding glycoprotein, is considered to be responsible for a number of transmissible spongiform encephalopathies (TSEs). The structural conversion of PrP from the normal cellular isoform (PrPC) to the post-translationally modified form (PrPSc) is thought to be relevant to Cu2+ binding to histidine residues. Rabbits are one of the few mammalian species that appear to be resistant to TSEs, because of the structural characteristics of the rabbit prion protein (RaPrPC) itself. Here we determined the three-dimensional local structure around the C-terminal high-affinity copper-binding sites using X-ray absorption near-edge structure combined with ab initio calculations in the framework of the multiple-scattering (MS) theory. Result shows that two amino acid resides, Gln97 and Met108, and two histidine residues, His95 and His110, are involved in binding this copper(II) ion. It might help us understand the roles of copper in prion conformation conversions, and the molecular mechanisms of prion-involved diseases.
Energy Technology Data Exchange (ETDEWEB)
Palacios G, J., E-mail: jpalacios@ipn.mx [IPN, Escuela Superior de Fisica y Matematicas, San Pedro Zacatenco 07738, Ciudad de Mexico (Mexico)
2016-11-01
The integrated intensity of Debye-Scherrer (D-S) rings, arising from an eventual second diffraction process of a diffracted X-ray beam, was calculated. This represents the amount of intensity not arriving at the detector as oriented to register the first diffraction process, and as result, a measure of secondary extinction. Thus the objective is to investigate in this way if secondary extinction affects measurements of X-ray diffraction from textured polycrystals. This has been suggested by differences of pole density maxima observed between measured first and second order pole figures in strongly textured materials. Calculations are performed for a detector scan (varying only 2θ), and the integrated intensity is determined for first and second order diffraction conditions of a general plane (hkl). Normalization through corresponding powder is performed. It is found that this special case of multiple scattering effect, indeed affects both orders essentially in the same way. If corresponding detector scan measurements verify this, then the observed differences between pole density maxima of pole figures of different order cannot be attributed to secondary extinction. Instead, they can be attributed to heterogeneous texture or error propagation. On the other hand, if the detector scans do exhibit a difference as that of pole density maxima, these differences can possibly be attributed to primary extinction. (Author)
Light propagation and emission in scattering media. Application to imaging of complex media
International Nuclear Information System (INIS)
Pierrat, Romain
2007-01-01
In this manuscript, we raise different aspects of the propagation and emission of electromagnetic waves in a scattering medium. In the first part, we show that the Radiative Transfer Equation (rte) is a very good tool to study light propagation in a complex medium. Thanks to this formalism, we study the evolution of the spatial coherence of the beam inside the medium, which is seen as a signature of the different transport regimes of photons (single scattering, multiple scattering, diffusive regime). Next, we derive rigorously the diffusion approximation by using a modal approach of the rte. In particular, we obtain that the diffusion coefficient is independent of the level of absorption in the dynamic regime while it depends on absorption in the case of the steady-state regime. Finally, we study the temporal fluctuations of the scattered intensity and show that the use of the rte allows to go beyond the diffusive regime described by the diffusing-waves spectroscopy theory (dws). Comparisons between numerical computations and experiments are realized in reflexion to underline the fundamental role of the anisotropy of the scattering, which is not described by the standard theory. The second part is dedicated to the study of light emission in complex media. First, we study the amplification of scattered light in a gain system called random laser and show that it exists a laser threshold in the incoherent feedback regime. This threshold is quantified by using a modal approach of the rte. Thanks to this formalism, we highlight the limitations of the diffusion approximation in such a system. Next, we study the modification of the fluorescent decay rate of a single molecule embedded in a complex medium. We derive a model allowing the replacement of the scattering medium by an homogeneous equivalent medium taking into account the multiple scattering and the interactions between scatterers. This model is validated by comparison with the value of the decay rate of the
Space-time picture of relativistic propagation of medium energy hadrons through nuclei
International Nuclear Information System (INIS)
Bleszynski, M.; Jaroszewicz, T.
1985-01-01
Relativistic virtual pair creation effects in hadron-nucleus scattering at medium energies are discussed. A close analogy is found between these effects (particle propagation backwards in time) and some of noneikonal correlations to the Glauber theory, arising from particle propagation backwards in space. In multiple scattering both effects appear only for configurations involving overlapping scatterers and lead to the non-additivity of phase shifts. The proper-time path-integral formalism is found to provide an intuitive geometrical picture of these phenomena. The relativistic corrections are estimated to be of the order k/(aE/sup 2/), k being the particle momentum, E its energy, and a the target size. At medium energies they are comparable to noneikonal corrections, of order 1/(ak). Both effects vanish at high energy, when particle propagation in space-time can be described by means of geometrical optics
Pion inelastic scattering and the pion-nucleus effective interaction
International Nuclear Information System (INIS)
Carr, J.A.
1983-01-01
This work examines pion inelastic scattering with the primary purpose of gaining a better understanding of the properties of the pion-nucleus interaction. The main conclusion of the work is that an effective interaction which incorporates the most obvious theoretical corrections to the impulse approximation does a good job of explaining pion elastic and inelastic scattering from zero to 200 MeV without significant adjustments to the strength parameters of the force. Watson's multiple scattering theory is used to develop a theoretical interaction starting from the free pion-nucleon interaction. Elastic scattering was used to calibrate the isoscalar central interaction. It was found that the impulse approximation did poorly at low energy, while the multiple scattering corrections gave good agreement with all of the data after a few minor adjustments in the force. The distorted wave approximation for the inelastic transition matrix elements are evaluated for both natural and unnatural parity excitations. The isoscalar natural parity transitions are used to test the reaction theory, and it is found that the effective interaction calibrated by elastic scattering produces good agreement with the inelastic data. Calculations are also shown for other inelastic and charge exchange reactions. It appears that the isovector central interaction is reasonable, but the importance of medium corrections cannot be determined. The unnatural parity transitions are also reasonably described by the theoretical estimate of the spin-orbit interaction, but not enough systematic data exists to reach a firm conclusion
Interstellar scattering and resolution limitations
International Nuclear Information System (INIS)
Dennison, B.
1987-01-01
Density irregularities in both the interplanetary medium and the ionized component of the interstellar medium scatter radio waves, resulting in limitations on the achievable resolution. Interplanetary scattering (IPS) is weak for most observational situations, and in principle the resulting phase corruption can be corrected for when observing with sufficiently many array elements. Interstellar scattering (ISS), on the other hand, is usually strong at frequencies below about 8 GHz, in which case intrinsic structure information over a range of angular scales is irretrievably lost. With the earth-space baselines now planned, it will be possible to search directly for interstellar refraction, which is suspected of modulating the fluxes of background sources. 14 references
Pelletron general purpose scattering chamber
International Nuclear Information System (INIS)
Chatterjee, A.; Kailas, S.; Kerekette, S.S.; Navin, A.; Kumar, Suresh
1993-01-01
A medium sized stainless steel scattering chamber has been constructed for nuclear scattering and reaction experiments at the 14UD pelletron accelerator facility. It has been so designed that several types of detectors, varying from small sized silicon surface barrier detectors to medium sized gas detectors and NaI detectors can be conveniently positioned inside the chamber for detection of charged particles. The chamber has been planned to perform the following types of experiments : angular distributions of elastically scattered particles, fission fragments and other charged particles, angular correlations for charged particles e.g. protons, alphas and fission fragments. (author). 2 figs
Steponavičius, Raimundas; Thennadil, Suresh N
2011-03-15
The effectiveness of a scatter correction approach based on decoupling absorption and scattering effects through the use of the radiative transfer theory to invert a suitable set of measurements is studied by considering a model multicomponent suspension. The method was used in conjunction with partial least-squares regression to build calibration models for estimating the concentration of two types of analytes: an absorbing (nonscattering) species and a particulate (absorbing and scattering) species. The performances of the models built by this approach were compared with those obtained by applying empirical scatter correction approaches to diffuse reflectance, diffuse transmittance, and collimated transmittance measurements. It was found that the method provided appreciable improvement in model performance for the prediction of both types of analytes. The study indicates that, as long as the bulk absorption spectra are accurately extracted, no further empirical preprocessing to remove light scattering effects is required.
International Nuclear Information System (INIS)
Vorbrugg, W.; Schaerpf, O.
1975-01-01
The small-angle scattering of Ni single crystals with (111) and (100) axis orientation is measured by a photographic method in the work-hardened state after tensile deformation. Parameters are the external magnetic field H parallel to the axis (600 2 ]<=8,8), and the elastic stress tausub(el)(0<=tausub(el)<=tausub(pl)) applied to the deformed crystals during the experiments. The scattering is found to be anisotropic and characteristic for the chosen orientation. The quantitative photometric analysis shows that the parameters mentioned above only influence the intensity but not the distribution of the scattered neutrons. The scattering increases with the elastic stress and decreases with the magnetic field. In particular, in the unloaded state there is a linear relation between the scattered intensity and the plastic shear stress. (author)
International Nuclear Information System (INIS)
Cui, P.X.; Lian, F.L.; Wang, Y.; Wen, Yi; Chu, W.S.; Zhao, H.F.; Zhang, S.; Li, J.; Lin, D.H.; Wu, Z.Y.
2014-01-01
Prion-related protein (PrP), a cell-surface copper-binding glycoprotein, is considered to be responsible for a number of transmissible spongiform encephalopathies (TSEs). The structural conversion of PrP from the normal cellular isoform (PrP C ) to the post-translationally modified form (PrP Sc ) is thought to be relevant to Cu 2+ binding to histidine residues. Rabbits are one of the few mammalian species that appear to be resistant to TSEs, because of the structural characteristics of the rabbit prion protein (RaPrP C ) itself. Here we determined the three-dimensional local structure around the C-terminal high-affinity copper-binding sites using X-ray absorption near-edge structure combined with ab initio calculations in the framework of the multiple-scattering (MS) theory. Result shows that two amino acid resides, Gln97 and Met108, and two histidine residues, His95 and His110, are involved in binding this copper(II) ion. It might help us understand the roles of copper in prion conformation conversions, and the molecular mechanisms of prion-involved diseases. - Highlights: ► The first structure of the metal ion binding site in RaPrP fifth copper-binding site. ► Quantitative determination by XANES spectroscopy combined with ab initio calculations. ► Provide a proof of the roles of copper in prion conformation conversions. ► Provide a proof of the molecular mechanisms of prion-involved diseases
Wang, Shaofeng; Ma, Xu; Zhang, Guoqing; Jia, Yongfeng; Hatada, Keisuke
2016-11-15
Hydrous ferric arsenate (HFA) is an important arsenic-bearing precipitate in the mining-impacted environment and hydrometallurgical tailings. However, there is no agreement on its local atomic structure. The local structure of HFA was reprobed by employing a full-potential multiple scattering (FPMS) analysis, density functional theory (DFT) calculations, and vibrational spectroscopy. The FPMS simulations indicated that the coordination number of the As-Fe, Fe-As, or both in HFA was approximately two. The DFT calculations constructed a structure of HFA with the formula of Fe(HAsO 4 ) x (H 2 AsO 4 ) 1-x (OH) y ·zH 2 O. The presence of protonated arsenate in HFA was also evidenced by vibrational spectroscopy. The As and Fe K-edge X-ray absorption near-edge structure spectra of HFA were accurately reproduced by FPMS simulations using the chain structure, which was also a reasonable model for extended X-Ray absorption fine structure fitting. The FPMS refinements indicated that the interatomic Fe-Fe distance was approximately 5.2 Å, consistent with that obtained by Mikutta et al. (Environ. Sci. Technol. 2013, 47 (7), 3122-3131) using wavelet analysis. All of the results suggested that HFA was more likely to occur as a chain with AsO 4 tetrahedra and FeO 6 octahedra connecting alternately in an isolated bidentate-type fashion. This finding is of significance for understanding the fate of arsenic and the formation of ferric arsenate minerals in an acidic environment.
Scattering theory of stochastic electromagnetic light waves.
Wang, Tao; Zhao, Daomu
2010-07-15
We generalize scattering theory to stochastic electromagnetic light waves. It is shown that when a stochastic electromagnetic light wave is scattered from a medium, the properties of the scattered field can be characterized by a 3 x 3 cross-spectral density matrix. An example of scattering of a spatially coherent electromagnetic light wave from a deterministic medium is discussed. Some interesting phenomena emerge, including the changes of the spectral degree of coherence and of the spectral degree of polarization of the scattered field.
Medium-energy ion reflection from solids
Mashkova, ES
1985-01-01
``Medium-Energy Ion Reflection from Solids'' analyses the results of experimental, theoretical and computer investigations on the process of scattering of ions by solid surfaces. Surface scattering is a relatively young and rapidly developing branch of the physics of atomic collisions and the literature on this subject has rapidly grown.As the first monograph devoted specifically to surface scattering of ions, this book is directed at scientists involved in ion-solid interaction studies.
Generalized internal multiple imaging
Zuberi, M. A. H.; Alkhalifah, Tariq Ali
2014-01-01
Internal multiples deteriorate the image when the imaging procedure assumes only single scattering, especially if the velocity model does not have sharp contrasts to reproduce such scattering in the Green’s function through forward modeling
Onset of color decoherence for soft gluon radiation in a medium
Mehtar-Tani, Y.; Salgado, C. A.; Tywoniuk, K.
2011-12-01
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.
Scattering of intermediate energy protons
International Nuclear Information System (INIS)
Chaumeaux, Alain.
1980-06-01
The scattering of 1 GeV protons appears to be a powerful means of investigating nuclear matter. We worked with SPESI and the formalism of Kerman-Mc Manus and Thaler. The amplitude of nucleon-nucleon scattering was studied as were the aspects of 1 GeV proton scattering (multiple scattering, absorption, spin-orbit coupling, N-N amplitude, KMT-Glauber comparison, second order effects). The results of proton scattering on 16 O, the isotopes of calcium, 58 Ni, 90 Zr and 208 Pb are given [fr
Yassine, Fatima; Bassil, Nathalie; Flouty, Roula; Chokr, Ali; Samrani, Antoine El; Boiteux, Gisèle; Tahchi, Mario El
2016-08-01
Gluconacetobacter genera are valued for bacterial cellulose (BC) and acetic acid production. BC is produced at optimal yields in classical microbiological media that are expensive for a large scale of production. In addition, BC usage for industrial purposes is limited due to low conversion rate into cellulose and to long incubation duration. In this paper, Gluconacetobacter isolated from apple vinegar was kinetically studied to evaluate cellulose production in presence of different carbon sources. Acetic and citric acid effect on Gluconacetobacter metabolism is clarified. It was shown that Gluconacetobacter uses glucose as a primary carbon source for cells growth and products formation. Acetic acid employment as a co-carbon source in Hestrin Schramm medium showed an increase of 17% in BC yield with a moderate decrease in the crystallite size of the resulting polymer. Copyright © 2016 Elsevier Ltd. All rights reserved.
A drift chamber tracking system for muon scattering tomography applications
Burns, J.; Quillin, S.; Stapleton, M.; Steer, C.; Snow, S.
2015-10-01
Muon scattering tomography (MST) allows the identification of shielded high atomic number (high-Z) materials by measuring the scattering angle of cosmic ray muons passing through an inspection region. Cosmic ray muons scatter to a greater degree due to multiple Coulomb scattering in high-Z materials than low-Z materials, which can be measured as the angular difference between the incoming and outgoing trajectories of each muon. Measurements of trajectory are achieved by placing position sensitive particle tracking detectors above and below the inspection volume. By localising scattering information, the point at which a series of muons scatter can be used to reconstruct an image, differentiating high, medium and low density objects. MST is particularly useful for differentiating between materials of varying density in volumes that are difficult to inspect visually or by other means. This paper will outline the experimental work undertaken to develop a prototype MST system based on drift chamber technology. The planar drift chambers used in this prototype measure the longitudinal interaction position of an ionising particle from the time taken for elections, liberated in the argon (92.5%), carbon dioxide (5%), methane (2.5%) gas mixture, to reach a central anode wire. Such a system could be used to enhance the detection of shielded radiological material hidden within regular shipping cargo.
Varghese, Babu; Rajan, Vinayakrishnan; van Leeuwen, Ton G.; Steenbergen, Wiendelt
2007-01-01
In optical Doppler measurements, the path length of the light is unknown. To facilitate quantitative measurements, we develop a phase-modulated Mach-Zehnder interferometer with separate fibers for illumination and detection. With this setup, path-length-resolved dynamic light scattering measurements
Light scattering by soap films
Vrij, A.
A theory is constructed describing the scattering from a liquid film (e.g., a soap film) of a light beam polarized normal to the plane of incidence. This scattering is due to the small irregular corrugations caused by thermal motion. The interference of the reflected incident beam with its multiple
Dynamic measurement of forward scattering
DEFF Research Database (Denmark)
Appel-Hansen, Jørgen; Rusch, W.
1975-01-01
A dynamic method for the measurement of forward scattering in a radio anechoic chamber is described. The quantity determined is the induced-field-ratio (IFR) of conducting cylinders. The determination of the IFR is highly sensitive to 1) multiple scattering between the cylinder and the obpring...
Energy Technology Data Exchange (ETDEWEB)
Nagao, Takashi; Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Nozawa, Takaya, E-mail: nagao@kusastro.kyoto-u.ac.jp [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)
2016-06-01
Many astronomical objects are surrounded by dusty environments. In such dusty objects, multiple scattering processes of photons by circumstellar (CS) dust grains can effectively alter extinction properties. In this paper, we systematically investigate the effects of multiple scattering on extinction laws for steady-emission sources surrounded by the dusty CS medium using a radiation transfer simulation based on the Monte Carlo technique. In particular, we focus on whether and how the extinction properties are affected by properties of CS dust grains by adopting various dust grain models. We confirm that behaviors of the (effective) extinction laws are highly dependent on the properties of CS grains, especially the total-to-selective extinction ratio R{sub V}, which characterizes the extinction law and can be either increased or decreased and compared with the case without multiple scattering. We find that the criterion for this behavior is given by a ratio of albedos in the B and V bands. We also find that either small silicate grains or polycyclic aromatic hydrocarbons are necessary for realizing a low value of R{sub V} as often measured toward SNe Ia if the multiple scattering by CS dust is responsible for their non-standard extinction laws. Using the derived relations between the properties of dust grains and the resulting effective extinction laws, we propose that the extinction laws toward dusty objects could be used to constrain the properties of dust grains in CS environments.
International Nuclear Information System (INIS)
Nagao, Takashi; Maeda, Keiichi; Nozawa, Takaya
2016-01-01
Many astronomical objects are surrounded by dusty environments. In such dusty objects, multiple scattering processes of photons by circumstellar (CS) dust grains can effectively alter extinction properties. In this paper, we systematically investigate the effects of multiple scattering on extinction laws for steady-emission sources surrounded by the dusty CS medium using a radiation transfer simulation based on the Monte Carlo technique. In particular, we focus on whether and how the extinction properties are affected by properties of CS dust grains by adopting various dust grain models. We confirm that behaviors of the (effective) extinction laws are highly dependent on the properties of CS grains, especially the total-to-selective extinction ratio R V , which characterizes the extinction law and can be either increased or decreased and compared with the case without multiple scattering. We find that the criterion for this behavior is given by a ratio of albedos in the B and V bands. We also find that either small silicate grains or polycyclic aromatic hydrocarbons are necessary for realizing a low value of R V as often measured toward SNe Ia if the multiple scattering by CS dust is responsible for their non-standard extinction laws. Using the derived relations between the properties of dust grains and the resulting effective extinction laws, we propose that the extinction laws toward dusty objects could be used to constrain the properties of dust grains in CS environments.
Basnet, Bikash
Tracking land surface dynamics over cloud-prone areas with complex mountainous terrain and a landscape that is heterogeneous at a scale of approximately 10 m, is an important challenge in the remote sensing of tropical regions in developing nations, due to the small plot sizes. Persistent monitoring of natural resources in these regions at multiple spatial scales requires development of tools to identify emerging land cover transformation due to anthropogenic causes, such as agricultural expansion and climate change. Along with the cloud cover and obstructions by topographic distortions due to steep terrain, there are limitations to the accuracy of monitoring change using available historical satellite imagery, largely due to sparse data access and the lack of high quality ground truth for classifier training. One such complex region is the Lake Kivu region in Central Africa. This work addressed these problems to create an effective process for monitoring the Lake Kivu region located in Central Africa. The Lake Kivu region is a biodiversity hotspot with a complex and heterogeneous landscape and intensive agricultural development, where individual plot sizes are often at the scale of 10m. Procedures were developed that use optical data from satellite and aerial observations at multiple scales to tackle the monitoring challenges. First, a novel processing chain was developed to systematically monitor the spatio-temporal land cover dynamics of this region over the years 1988, 2001, and 2011 using Landsat data, complemented by ancillary data. Topographic compensation was performed on Landsat reflectances to avoid the strong illumination angle impacts and image compositing was used to compensate for frequent cloud cover and thus incomplete annual data availability in the archive. A systematic supervised classification, using the state-of-the-art machine learning classifier Random Forest, was applied to the composite Landsat imagery to obtain land cover thematic maps
International Nuclear Information System (INIS)
Hategan, Cornel; Comisel, Horia; Ionescu, Remus A.
2004-01-01
The quasiresonant scattering consists from a single channel resonance coupled by direct interaction transitions to some competing reaction channels. A description of quasiresonant Scattering, in terms of generalized reduced K-, R- and S- Matrix, is developed in this work. The quasiresonance's decay width is, due to channels coupling, smaller than the width of the ancestral single channel resonance (resonance's direct compression). (author)
Donne, A. J. H.
1994-01-01
Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wave vector is much larger than the plasma Debye length, the total scattered power is
Kernel integration scatter model for parallel beam gamma camera and SPECT point source response
International Nuclear Information System (INIS)
Marinkovic, P.M.
2001-01-01
Scatter correction is a prerequisite for quantitative single photon emission computed tomography (SPECT). In this paper a kernel integration scatter Scatter correction is a prerequisite for quantitative SPECT. In this paper a kernel integration scatter model for parallel beam gamma camera and SPECT point source response based on Klein-Nishina formula is proposed. This method models primary photon distribution as well as first Compton scattering. It also includes a correction for multiple scattering by applying a point isotropic single medium buildup factor for the path segment between the point of scatter an the point of detection. Gamma ray attenuation in the object of imaging, based on known μ-map distribution, is considered too. Intrinsic spatial resolution of the camera is approximated by a simple Gaussian function. Collimator is modeled simply using acceptance angles derived from the physical dimensions of the collimator. Any gamma rays satisfying this angle were passed through the collimator to the crystal. Septal penetration and scatter in the collimator were not included in the model. The method was validated by comparison with Monte Carlo MCNP-4a numerical phantom simulation and excellent results were obtained. The physical phantom experiments, to confirm this method, are planed to be done. (author)
International Nuclear Information System (INIS)
Sitenko, A.
1991-01-01
This book emerged out of graduate lectures given by the author at the University of Kiev and is intended as a graduate text. The fundamentals of non-relativistic quantum scattering theory are covered, including some topics, such as the phase-function formalism, separable potentials, and inverse scattering, which are not always coverded in textbooks on scattering theory. Criticisms of the text are minor, but the reviewer feels an inadequate index is provided and the citing of references in the Russian language is a hindrance in a graduate text
Entanglement degradation in depolarizing light scattering
International Nuclear Information System (INIS)
Aiello, A.; Woerdman, J.P.
2005-01-01
Full text: In the classical regime, when a beam of light is scattered by a medium, it may emerge partially or completely depolarized depending on the optical properties of the medium. Correspondingly, in the quantum regime, when an entangled two-photon pair is scattered, the classical depolarization may result in an entanglement degradation. Here, relations between photon scattering, entanglement and multi-mode detection are investigated. We establish a general framework in which one- and two-photon elastic scattering processes can be discussed, and we focus on the study of the intrinsic entanglement degradation caused by a multi-mode detection. We show that any multi-mode scattered state cannot maximally violate the Bell-CHSH inequality because of the momentum spread. The results presented here have general validity and can be applied to both deterministic and random scattering processes. (author)
Intermediate energy nucleon-deuteron scattering theory.
Wilson, J. W.
1973-01-01
Sloan's conclusion (1969) that terms of the multiple-scattering series beyond single scattering contribute only to S- and P-wave amplitudes in an S-wave separable model is examined. A comparison of experiments with the calculation at 146 MeV shows that the conclusion is valid in nucleon-deuteron scattering applications.
On the K+-nucleus elastic scattering
International Nuclear Information System (INIS)
Ning, P.; Men, D.
1991-01-01
In this paper conventional and unconventional nuclear medium effects in the K + scattering are briefly reviewed. Microscopic calculations of the K + elastic scattering on 4 He, 12 C, 40 Ca, 120 Sn at 800 MeV/c are performed and then possible swellings of nucleons in nuclei are discussed
Inverse acoustic problem of N homogeneous scatterers
DEFF Research Database (Denmark)
Berntsen, Svend
2002-01-01
The three-dimensional inverse acoustic medium problem of N homogeneous objects with known geometry and location is considered. It is proven that one scattering experiment is sufficient for the unique determination of the complex wavenumbers of the objects. The mapping from the scattered fields...
International Nuclear Information System (INIS)
Stirling, W.G.; Perry, S.C.
1996-01-01
We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO 3 is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs
Effective Medium Theory for Anisotropic Metamaterials
Zhang, Xiujuan
2017-01-01
great attention recently. As an easily attainable device, a grating may be the simplest version of metasurfaces. Here, an analytical EMT for gratings made of cylinders is developed by using the multiple scattering theory (MST) method and the lattice sum
International Nuclear Information System (INIS)
Yu-Lin, Feng; Xiao-Zhou, Liu; Jie-Hui, Liu; Li, Ma
2009-01-01
Based on an equivalent medium approach, this paper presents a model describing the nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores. The influences of pores' nonlinear oscillations on sound attenuation, sound dispersion and an equivalent acoustic nonlinearity parameter are discussed. The calculated results show that the attenuation increases with an increasing volume fraction of micropores. The peak of sound velocity and attenuation occurs at the resonant frequency of the micropores while the peak of the equivalent acoustic nonlinearity parameter occurs at the half of the resonant frequency of the micropores. Furthermore, multiple scattering has been taken into account, which leads to a modification to the effective wave number in the equivalent medium approach. We find that these linear and nonlinear acoustic parameters need to be corrected when the volume fraction of micropores is larger than 0.1%