Rayleigh scattering under light-atom coherent interaction
Takamizawa, Akifumi; Shimoda, Koichi
2012-01-01
Semi-classical calculation of an oscillating dipole induced in a two-level atom indicates that spherical radiation from the dipole under coherent interaction, i.e., Rayleigh scattering, has a power level comparable to that of spontaneous emission resulting from an incoherent process. Whereas spontaneous emission is nearly isotropic and has random polarization generally, Rayleigh scattering is strongly anisotropic and polarized in association with incident light. In the case where Rabi frequen...
DEFF Research Database (Denmark)
Birkedal, Dan; Shah, Jagdeep; Pfeiffer, L. N.
1999-01-01
Recent investigations of secondary emission from quantum well excitons following ultrafast resonant excitation have demonstrated an intricate interplay of coherent Rayleigh scattering and incoherent luminescence. We have very recently demonstrated that it is possible to isolate and time resolve...... the coherent field associated with Rayleigh component using ultrafast spectral interferometry or Tadpole, thus, obtaining substantial and new information of the nature of resonant secondary emission. Our observation demonstrates that Rayleigh scattering from static disorder is inherently a non-ergodic process...... invalidating the use of current theories using ensemble averages to describe our observations. Furthermore, we report here a new and hitherto unknown coherent scattering mechanism involving the two-photon coherence associated with the biexciton transition. The process leaves an exciton behind taking up...
Recent results in Rayleigh scattering
International Nuclear Information System (INIS)
Kahane, S.; Shahal, O.; Moreh, R.; Ben-Gurion Univ. of the Negev, Beer-Sheva
1997-01-01
New measurements of Rayleigh scattering, employing neutron capture γ rays are presented. Experimental conditions are achieved such that the Rayleigh contribution is dominant and much larger than other competing coherent process. A detailed comparison with the modified relativistic form factor approximation (MRFF) is made. It is found that MRFF overestimates the true cross sections by 3-4%. (author)
DEFF Research Database (Denmark)
Birkedal, Dan; Shah, Jagdeep; Shchegrov, Andrei V.
2000-01-01
Resonant Rayleigh scattering from quantum well excitons is investigated using ultrafast spectral interferometry. We isolate the coherent Rayleigh scattering from incoherent luminescence in a single speckle. Averaging the resonant Rayleigh intensity over several speckles allows us to identify...... features in support of quantum corrections to the classical description of the underlying scattering process....
Dynamical narrowing of the Rayleigh scattering ring from a semiconductor microcavity
DEFF Research Database (Denmark)
Langbein, W.; Hvam, Jørn Märcher
2001-01-01
In resonant secondary emission of light (SE), scattering by static disorder leads to coherent resonant Rayleigh scattering (RRS), while the scattering with other quasi-particles (e.g. phonons) leads to an incoherent emission called photoluminescence (PL). For a bare quantum well (QW) the SE does...
Rayleigh scattering in an emitter-nanofiber-coupling system
Tang, Shui-Jing; Gao, Fei; Xu, Da; Li, Yan; Gong, Qihuang; Xiao, Yun-Feng
2017-04-01
Scattering is a general process in both fundamental and applied physics. In this paper, we investigate Rayleigh scattering of a solid-state-emitter coupled to a nanofiber, by S -matrix-like theory in k -space description. Under this model, both Rayleigh scattering and dipole interaction are studied between a two-level artificial atom embedded in a nanocrystal and fiber modes (guided and radiation modes). It is found that Rayleigh scattering plays a critical role in the transport properties and quantum statistics of photons. On the one hand, Rayleigh scattering produces the transparency in the optical transmitted field of the nanofiber, accompanied by the change of atomic phase, population, and frequency shift. On the other hand, the interference between two kinds of scattering fields by Rayleigh scattering and dipole transition modifies the photon statistics (second-order autocorrelation function) of output fields, showing a strong wavelength dependence. This study provides guidance for the solid-state emitter acting as a single-photon source and can be extended to explore the scattering effect in many-body physics.
Rayleigh scattering and depolarization ratio in linear alkylbenzene
International Nuclear Information System (INIS)
Liu, Qian; Zhou, Xiang; Huang, Wenqian; Zhang, Yuning; Wu, Wenjie; Luo, Wentai; Yu, Miao; Zheng, Yangheng; Zhou, Li; Cao, Jun; Wang, Yifang
2015-01-01
It is planned to use linear alkylbenzene (LAB) as the organic solvent for the Jiangmen Underground Neutrino Observatory (JUNO) liquid scintillator detectors, due to its ultra-transparency. However, the current Rayleigh scattering length calculation for LAB disagrees with the experimental measurement. This paper reports for the first time that the Rayleigh scattering of LAB is anisotropic, with a depolarization ratio of 0.31±0.01(stat.)±0.01(sys.). We use an indirect method for Rayleigh scattering measurement with the Einstein–Smoluchowski–Cabannes formula, and the Rayleigh scattering length of LAB is determined to be 28.2±1.0 m at 430 nm
Rayleigh scattering in few-mode optical fibers.
Wang, Zhen; Wu, Hao; Hu, Xiaolong; Zhao, Ningbo; Mo, Qi; Li, Guifang
2016-10-24
The extremely low loss of silica fibers has enabled the telecommunication revolution, but single-mode fiber-optic communication systems have been driven to their capacity limits. As a means to overcome this capacity crunch, space-division multiplexing (SDM) using few-mode fibers (FMF) has been proposed and demonstrated. In single-mode optical fibers, Rayleigh scattering serves as the dominant mechanism for optical loss. However, to date, the role of Rayleigh scattering in FMFs remains elusive. Here we establish and experimentally validate a general model for Rayleigh scattering in FMFs. Rayleigh backscattering not only sets the intrinsic loss limit for FMFs but also provides the theoretical foundation for few-mode optical time-domain reflectometry, which can be used to probe perturbation-induced mode-coupling dynamics in FMFs. We also show that forward inter-modal Rayleigh scattering ultimately sets a fundamental limit on inter-modal-crosstalk for FMFs. Therefore, this work not only has implications specifically for SDM systems but also broadly for few-mode fiber optics and its applications in amplifiers, lasers, and sensors in which inter-modal crosstalk imposes a fundamental performance limitation.
RAYLEIGH SCATTERING MODELS WITH CORRELATION INTEGRAL
Directory of Open Access Journals (Sweden)
S. F. Kolomiets
2014-01-01
Full Text Available This article offers one of possible approaches to the use of the classical correlation concept in Rayleigh scattering models. Classical correlation in contrast to three types of correlations corresponding to stochastic point flows opens the door to the efficient explanation of the interaction between periodical structure of incident radiation and discreet stochastic structure of distributed scatters typical for Rayleigh problems.
Otugen, M. Volkan; Popovic, Svetozar
1996-01-01
Ongoing research in Rayleigh scattering diagnostics for variable density low speed flow applications and for supersonic flow measurements are described. During the past several years, the focus has been on the development and use of a Nd:YAG-based Rayleigh scattering system with improved signal-to-noise characteristics and with applicability to complex, confined flows. This activity serves other research projects in the Aerodynamics Laboratory which require the non-contact, accurate, time-frozen measurement of gas density, pressure, and temperature (each separately), in a fairly wide dynamic range of each parameter. Recently, with the acquisition of a new seed-injected Nd:YAG laser, effort also has been directed to the development of a high-speed velocity probe based on a spectrally resolved Rayleigh scattering technique.
Rayleigh scattering from ions near threshold
International Nuclear Information System (INIS)
Roy, S.C.; Gupta, S.K.S.; Kissel, L.; Pratt, R.H.
1988-01-01
Theoretical studies of Rayleigh scattering of photons from neon atoms with different degrees of ionization, for energies both below and above the K-edges of the ions, are presented. Some unexpected structures both in Rayleigh scattering and in photoionization from neutral and weakly ionized atoms, very close to threshold, have been reported. It has recently been realized that some of the predicted structures may have a nonphysical origin and are due to the limitation of the independent-particle model and also to the use of a Coulombic Latter tail. Use of a K-shell vacancy potential - in which an electron is assumed to be removed from the K-shell - in calculating K-shell Rayleigh scattering amplitudes removes some of the structure effects near threshold. We present in this work a discussion of scattering angular distributions and total cross sections, obtained utilizing vacancy potentials, and compare these predictions with those previously obtained in other potential model. (author) [pt
SFERXS, Photoabsorption, Coherent, Incoherent Scattering Cross-Sections Function for Shielding
International Nuclear Information System (INIS)
Legarda, F.; Mtz de la Fuente, O.; Herranz, M.
2002-01-01
Description of program or function: The use of electromagnetic radiation cross-sections in radiation shielding calculations and more generally in transport theory applications actually requires an interpolation between values which are tabulated for certain values of the energy. In order to facilitate this process and to reduce the computer memory requirements, we have developed, by a least squares method, a set of functions which represents the cross-sections for the photoelectric absorption, the coherent (Rayleigh) and the incoherent (Compton) scattering (1). For this purpose we have accepted as true values the ones tabulated by Storm and Israel (2) for the photoeffect, by Hubbell et Al. (3) for the incoherent scattering and by Hubbell and Overbo (4) for the coherent scattering
Depolarization Rayleigh scattering as a means of molecular concentration determination in plasmas
Meulenbroeks, R.F.G.; Schram, D.C.; Jaegers, L.J.M.; Sanden, van de M.C.M.
1992-01-01
The difference in polarization for Rayleigh scattered radiation on spherically and nonspherically symmetric scattering objects has been used to obtain molecular species concentrations in plasmas of simple composition. Using a Rayleigh scattering diagnostic, the depolarized component of the scattered
DEFF Research Database (Denmark)
Elm, Jonas; Norman, Patrick; Bilde, Merete
2014-01-01
The Rayleigh and hyper Rayleigh scattering properties of the binary (H 2SO4)(H2O)n and ternary (H 2SO4)(NH3)(H2O)n clusters are investigated using a quantum mechanical response theory approach. The molecular Rayleigh scattering intensities are expressed using the dipole polarizability α...... and hyperpolarizability β tensors. Using density functional theory, we elucidate the effect of cluster morphology on the scattering properties using a combinatorial sampling approach. We find that the Rayleigh scattering intensity depends quadratically on the number of water molecules in the cluster and that a single...... ammonia molecule is able to induce a high anisotropy, which further increases the scattering intensity. The hyper Rayleigh scattering activities are found to be extremely low. This study presents the first attempt to map the scattering of atmospheric molecular clusters using a bottom-up approach...
Rayleigh scattering in coupled microcavities: theory.
Vörös, Zoltán; Weihs, Gregor
2014-12-03
In this paper we theoretically study how structural disorder in coupled semiconductor heterostructures influences single-particle scattering events that would otherwise be forbidden by symmetry. We extend the model of Savona (2007 J. Phys.: Condens. Matter 19 295208) to describe Rayleigh scattering in coupled planar microcavity structures, and find that effective filter theories can be ruled out.
Loranger, Sébastien; Parent, François; Lambin-Iezzi, Victor; Kashyap, Raman
2016-02-01
Rayleigh scatter in optical fiber communication systems has long been considered a nuisance as a loss mechanism, although applications have used such scatter to probe the fiber for faults and propagation loss using time domain reflectometry (OTDR). It is however only with the development of Frequency domain reflectometry (OFDR) and coherent-phase OTDR that Rayleigh scatter has been probed to its deepest and can now be used to measure strain and temperature along a fiber, leading to the first distributed sensing applications. However, Rayleigh scatter remains very weak giving rise to very small signals which limits the technique for sensing. We show here a new technique to significantly enhance the Rayleigh scatter signal by at least two orders of magnitude, in a standard optical fiber with simple UV exposure of the core. A study of various exposures with different types of fibers has been conducted and a phenomenological description developed. We demonstrate that such an increase in signal can enhance the temperature and strain sensitivity by an order of magnitude for distributed sensing with an OFDR technique. Such improved performance can lead to temperature/strain RMS noise levels of 6 mK and 50 nɛ for 1 cm spatial resolution in UV exposed SMF-28, compared to the typical noise level of 100 mK for the same spatial resolution in the similar unexposed fiber.
Chemical Applications of Second Harmonic Rayleigh Scattering ...
Indian Academy of Sciences (India)
Chemical Applications of Second Harmonic Rayleigh Scattering Puspendu Kumar Das Department of Inorganic and Physical Chemistry Indian Institute of Science Bangalore 560012, India pkdas@ipc.iisc.ernet.in.
The effect of pressure on spontaneous Rayleigh-Brillouin scattering spectrum in nitrogen
Yang, Chuanyin; Wu, Tao; Shang, Jingcheng; Zhang, Xinyi; Hu, Rongjing; He, XingDao
2018-05-01
In order to study the effect of gas pressure on spontaneous Rayleigh-Brillouin scattering spectrum and verify the validity of Tenti S6 model at pressures up to 8 atm, the spontaneous Rayleigh-Brillouin scattering experiment in nitrogen was performed for a wavelength of 532 nm at the constant room temperature of 296 K and a 90° scattering angle. By comparing the experimental spectrum with the theoretical spectrum, the normalized root mean square deviation was calculated and found less than 2.2%. It is verified that Tenti S6 model can be applied to the spontaneous Rayleigh-Brillion scattering of nitrogen under higher pressures. The results of the experimental data analysis demonstrate that pressure has more effect on Brillouin peak intensity and has negligible effect on Brillouin frequency shift, and pressure retrieval based on spontaneous Rayleigh-Brillouin scattering profile is a promising method for remote of pressure, such as harsh environment applications. Some factors that caused experiment deviations are also discussed.
Rayleigh scattering and nonlinear inversion of elastic waves
Energy Technology Data Exchange (ETDEWEB)
Gritto, Roland [Univ. of California, Berkeley, CA (United States)
1995-12-01
Rayleigh scattering of elastic waves by an inclusion is investigated and the limitations determined. In the near field of the inhomogeneity, the scattered waves are up to a factor of 300 stronger than in the far field, excluding the application of the far field Rayleigh approximation for this range. The investigation of the relative error as a function of parameter perturbation shows a range of applicability broader than previously assumed, with errors of 37% and 17% for perturbations of -100% and +100%, respectively. The validity range for the Rayleigh limit is controlled by large inequalities, and therefore, the exact limit is determined as a function of various parameter configurations, resulting in surprisingly high values of up to k_{p}R = 0.9. The nonlinear scattering problem can be solved by inverting for equivalent source terms (moments) of the scatterer, before the elastic parameters are determined. The nonlinear dependence between the moments and the elastic parameters reveals a strong asymmetry around the origin, which will produce different results for weak scattering approximations depending on the sign of the anomaly. Numerical modeling of cross hole situations shows that near field terms are important to yield correct estimates of the inhomogeneities in the vicinity of the receivers, while a few well positioned sources and receivers considerably increase the angular coverage, and thus the model resolution of the inversion parameters. The pattern of scattered energy by an inhomogeneity is complicated and varies depending on the object, the wavelength of the incident wave, and the elastic parameters involved. Therefore, it is necessary to investigate the direction of scattered amplitudes to determine the best survey geometry.
In situ nanoparticle diagnostics by multi-wavelength Rayleigh-Mie scattering ellipsometry
Gebauer, G
2003-01-01
We present and discuss the method of multiple-wavelength Rayleigh-Mie scattering ellipsometry for the in situ analysis of nanoparticles. It is applied to the problem of nanoparticles suspended in low-pressure plasmas. We discuss experimental results demonstrating that the size distribution and the complex refractive index can be determined with high accuracy and present a study on the in situ analysis of etching of melamine-formaldehyde nanoparticles suspended in an oxygen plasma. It is also shown that particles with a shell structure (core plus mantle) can be analysed by Rayleigh-Mie scattering ellipsometry. Rayleigh-Mie scattering ellipsometry is also applicable to in situ analysis of nanoparticles under high gas pressures and in liquids.
Measurement of the Rayleigh scattering length in liquid scintillators for JUNO
Energy Technology Data Exchange (ETDEWEB)
Hackspacher, Paul [Johannes Gutenberg-Universitaet Mainz, PRISMA Excellence Cluster (Germany); Collaboration: JUNO-Collaboration
2016-07-01
In liquid scintillator neutrino detectors such as the upcoming Jiangmen Underground Neutrino Observatory (JUNO), neutrino interactions are being detected by means of inverse beta decay and analysis of the resulting luminescent light. In order to reliably reconstruct these events from photomultiplier signals, the scattering properties of the detector materials need to be sufficiently well known. In the LAB-based liquid scintillator that has been proposed for JUNO, the primary contribution to the scattering process comes from Rayleigh scattering. The characteristic Rayleigh scattering length can be experimentally obtained in an optical laboratory setup. This talk presents the approach, the current status and the future plans of the experiment.
International Nuclear Information System (INIS)
Bayer, Charles
1973-06-01
The experimental variation of the scattered light with the number of scattering centers and with the refraction index of gases is in agreement with the theoretical Rayleigh scattering. A direct calibration System gives the absolute value of the Rayleigh ratio. The experimental value appears to be half of the theoretical one. (author) [fr
International Nuclear Information System (INIS)
Chesskaya, T.Yu.
1998-01-01
The Rayleigh scattering spectrum of the Moessbauer radiation is plotted on the model simulating globular macromolecules. The modeling results are compared with experimental data on the spectra of the Rayleigh scattering of the Moessbauer radiation for various moisture content and hydratation dependence of the elastic scattering portion
Direct measurement of the Rayleigh scattering cross section in various gases
International Nuclear Information System (INIS)
Sneep, Maarten; Ubachs, Wim
2005-01-01
Using the laser-based technique of cavity ring-down spectroscopy extinction measurements have been performed in various gases straightforwardly resulting in cross sections for Rayleigh scattering. For Ar and N 2 measurements are performed in the range 470-490nm, while for CO 2 cross sections are determined in the wider range 470-570nm. In addition to these gases also for N 2 O, CH 4 , CO, and SF 6 the scattering cross section is determined at 532nm, a wavelength of importance for lidar applications and combustion laser diagnostics. In O 2 the cross section at 532nm is found to depend on pressure due to collision-induced light absorption. The obtained cross sections validate the cross sections for Rayleigh scattering as derived from refractive indices and depolarization ratios through Rayleigh's theory at the few %-level, although somewhat larger discrepancies are found for CO, N 2 O and CH 4
Filtered Rayleigh Scattering Measurements in a Buoyant Flow Field
National Research Council Canada - National Science Library
Meents, Steven M
2008-01-01
Filtered Rayleigh Scattering (FRS) is a non-intrusive, laser-based flow characterization technique that consists of a narrow linewidth laser, a molecular absorption filter, and a high resolution camera behind the filter to record images...
Coherent structures in ablatively compressed ICF targets and Rayleigh-Taylor instability
International Nuclear Information System (INIS)
Pant, H.C.; Desai, T.
1996-01-01
One of the major issues in laser induced inertial confinement fusion (ICF) is a stable ablative compression of spherical fusion pellets. The main impediment in achievement of this objective is Rayleigh-Taylor instability at the pellet's ablation front. Under sufficiently high acceleration this instability can grow out of noise. However, it can also arise either due to non-uniform laser intensity distribution over the pellet surface or due to pellet wall areal mass irregularity. Coherent structures in the dense target behind the ablation front can be effectively utilised for stabilisation of the Rayleigh-Taylor phenomenon. Such coherent structures in the form of a super lattice can be created by doping the pellet pusher with high atomic number (Z) micro particles. A compressed-cool pusher under laser irradiation behaves like a strongly correlated non ideal plasma when compressed to sufficiently high density such that the non ideality parameter exceeds unity. Moreover, the nonideality parameter for high Z microinclusions may exceed a critical value of 180 and as a consequence they remain in the form of intact clusters, maintaining the superlattice intact during ablative acceleration. Micro-hetrogeneity and its superlattice plays an important role in stabilization of Rayleigh-Taylor instability, through a variety of mechanisms. (orig.)
Meijer, A.S.; Wijn, de A.S.; Peters, M.F.E.; Dam, N.J.; Water, van de W.
2010-01-01
We investigate coherent Rayleigh–Brillouin spectroscopy as an efficient process to measure the bulk viscosity of gases at gigahertz frequencies. Scattered spectral distributions are measured using a Fizeau spectrometer. We discuss the statistical error due to the fluctuating mode structure of the
Directory of Open Access Journals (Sweden)
K. A. Shapovalov
2015-01-01
Full Text Available The paper concerns the light scattering problem of biological objects of complicated structure.It considers optically “soft” (having a refractive index close to that of a surrounding medium homogeneous cylindrical capsules, composed of three parts: central one that is cylindrical and two symmetrical rounding end caps. Such capsules can model more broad class of biological objects than the ordinary shapes of a spheroid or sphere. But, unfortunately, if a particle has other than a regular geometrical shape, then it is very difficult or impossible to solve the scattering problem analytically in its most general form that oblige us to use numerical and approximate analytical methods. The one of such approximate analytical method is the Rayleigh-Gans-Debye approximation (or the first Born approximation.So, the Rayleigh-Gans-Debye approximation is valid for different objects having size from nanometer to millimeter and depending on wave length and refractive index of an object under small phase shift of central ray.The formulas for light scattering amplitude of cylindrical capsule with arbitrary end caps in the Rayleigh-Gans-Debye approximation in scalar form are obtained. Then the light scattering phase function [or element of scattering matrix f11] for natural incident light (unpolarized or arbitrary polarized light is calculated.Numerical results for light scattering phase functions of cylindrical capsule with conical, spheroidal, paraboloidal ends in the Rayleigh-Gans-Debye approximation are compared. Also numerical results for light scattering phase function of cylindrical capsule with conical ends in the Rayleigh-Gans-Debye approximation and in the method of Purcell-Pennypacker (or Discrete Dipole method are compared. The good agreement within an application range of the RayleighGans-Debye approximation is obtained.Further continuation of the work, perhaps, is a consideration of multilayer cylindrical capsule in the Rayleigh
Chemical Applications of Second Harmonic Rayleigh Scattering ...
Indian Academy of Sciences (India)
Chemical Applications of Second Harmonic Rayleigh Scattering Puspendu Kumar Das Department of Inorganic and Physical Chemistry Indian Institute of Science Bangalore 560012, India pkdas@ipc.iisc.ernet.in · Slide 2 · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13.
In-Flight Calibration of GF-1/WFV Visible Channels Using Rayleigh Scattering
Directory of Open Access Journals (Sweden)
Xingfeng Chen
2017-05-01
Full Text Available China is planning to launch more and more optical remote-sensing satellites with high spatial resolution and multistep gains. Field calibration, the current operational method of satellite in-flight radiometric calibration, still does not have enough capacity to meet these demands. Gaofen-1 (GF-1, as the first satellite of the Chinese High-resolution Earth Observation System, has been specially arranged to obtain 22 images over clean ocean areas using the Wide Field Viewing camera. Following this, Rayleigh scattering calibration was carried out for the visible channels with these images after the appropriate data processing steps. To guarantee a high calibration precision, uncertainty was analyzed in advance taking into account ozone, aerosol optical depth (AOD, seawater salinity, chlorophyll concentration, wind speed and solar zenith angle. AOD and wind speed were found to be the biggest error sources, which were also closely coupled to the solar zenith angle. Therefore, the best sample data for Rayleigh scattering calibration were selected at the following solar zenith angle of 19–22° and wind speed of 5–13 m/s to reduce the reflection contributed by the water surface. The total Rayleigh scattering calibration uncertainties of visible bands are 2.44% (blue, 3.86% (green, and 4.63% (red respectively. Compared with the recent field calibration results, the errors are −1.69% (blue, 1.83% (green, and −0.79% (red. Therefore, the Rayleigh scattering calibration can become an operational in-flight calibration method for the high spatial resolution satellites.
Instantaneous Rayleigh scattering from excitons localized in monolayer islands
DEFF Research Database (Denmark)
Langbein, Wolfgang; Leosson, Kristjan; Jensen, Jacob Riis
2000-01-01
We show that the initial dynamics of Rayleigh scattering from excitons in quantum wells can be either instantaneous or delayed, depending on the exciton ensemble studied. For excitation of the entire exciton resonance, a finite rise time given by the inverse inhomogeneous broadening: of the exciton...
Spontaneous Rayleigh-Brillouin scattering spectral analysis based on the Wiener filter
Directory of Open Access Journals (Sweden)
Tao Wu
2018-01-01
Full Text Available In this paper, a spontaneous Rayleigh-Brillouin scattering spectrometer is developed to measure the gaseous spontaneous Rayleigh-Brillouin scattering profiles over the pressure range from 1 to 5 atm for a wavelength of 532nm at a constant room temperature of 296K and a 90o scattering angle. In order to make a direct comparison between the experimentally obtained spectrum and the theoretical spectrum calculated from the Tenti S6 model, the measured spontaneous Rayleigh-Brillouin scattering signal is deconvolved by the Wiener filtering. The purpose is to remove the effect on the spectrum by the transmission function of the Fabry-Perrot scanning interferometer. The results of the comparison show that the deconvolved spectra are consistent with the theoretical spectra calculated from the Tenti S6 model, and thus confirm that the deconvolution based on the Wiener filter is able to process the measured spectra and improve the spectral resolution. Some factors that influence the accuracy of deconvolution are analyzed and discussed. At the same time, another comparison between the raw experimentally obtained spectra and the theoretical spectra calculated by convolving the Tenti S6 model with instrument function of the measurement system is performed in the same experimental condition. The results of the two comparisons show that, compared with the raw experimentally obtained spectrum, the deconvolved spectrum matches the theoretically calculated spectrum more accurately under lower pressure (≤2atm than under relative higher pressure (>2atm.
RAYLEIGH SCATTERING IN THE ATMOSPHERE OF THE WARM EXO-NEPTUNE GJ 3470B
International Nuclear Information System (INIS)
Dragomir, Diana; Benneke, Björn; Pearson, Kyle A.; Crossfield, Ian J. M.; Barman, Travis; Eastman, Jason; Biddle, Lauren I.
2015-01-01
GJ 3470b is a warm Neptune-size planet transiting an M dwarf star. Like the handful of other small exoplanets for which transmission spectroscopy has been obtained, GJ 3470b exhibits a flat spectrum in the near- and mid-infrared. Recently, a tentative detection of Rayleigh scattering in its atmosphere has been reported. This signal manifests itself as an observed increase of the planetary radius as a function of decreasing wavelength in the visible. We set out to verify this detection and observed several transits of this planet with the LCOGT network and the Kuiper telescope in four different bands (Sloan g, Sloan i, Harris B, and Harris V). Our analysis reveals a strong Rayleigh scattering slope, thus confirming previous results. This makes GJ 3470b the smallest known exoplanet with a detection of Rayleigh scattering. We find that the most plausible scenario is a hydrogen/helium-dominated atmosphere covered by clouds which obscure absorption features in the infrared and hazes which give rise to scattering in the visible. Our results demonstrate the feasibility of exoplanet atmospheric characterization from the ground, even with meter-class telescopes
RAYLEIGH SCATTERING IN THE ATMOSPHERE OF THE WARM EXO-NEPTUNE GJ 3470B
Energy Technology Data Exchange (ETDEWEB)
Dragomir, Diana [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive Suite 102, Goleta, CA 93117 (United States); Benneke, Björn [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Pearson, Kyle A. [Department of Physics and Astronomy, Northern Arizona University, Flagstaff, AZ 86001 (United States); Crossfield, Ian J. M.; Barman, Travis [Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Eastman, Jason [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Biddle, Lauren I., E-mail: diana@oddjob.uchicago.edu [Gemini Observatory, Northern Operations Center, 670 N. Aohoku Place, Hilo, HI 96720 (United States)
2015-12-01
GJ 3470b is a warm Neptune-size planet transiting an M dwarf star. Like the handful of other small exoplanets for which transmission spectroscopy has been obtained, GJ 3470b exhibits a flat spectrum in the near- and mid-infrared. Recently, a tentative detection of Rayleigh scattering in its atmosphere has been reported. This signal manifests itself as an observed increase of the planetary radius as a function of decreasing wavelength in the visible. We set out to verify this detection and observed several transits of this planet with the LCOGT network and the Kuiper telescope in four different bands (Sloan g, Sloan i, Harris B, and Harris V). Our analysis reveals a strong Rayleigh scattering slope, thus confirming previous results. This makes GJ 3470b the smallest known exoplanet with a detection of Rayleigh scattering. We find that the most plausible scenario is a hydrogen/helium-dominated atmosphere covered by clouds which obscure absorption features in the infrared and hazes which give rise to scattering in the visible. Our results demonstrate the feasibility of exoplanet atmospheric characterization from the ground, even with meter-class telescopes.
Energy Technology Data Exchange (ETDEWEB)
Appaji Gowda, S.B. [Department of Studies in Physics, Manasagangothri, University of Mysore, Mysore 570006 (India); Umesh, T.K. [Department of Studies in Physics, Manasagangothri, University of Mysore, Mysore 570006 (India)]. E-mail: tku@physics.uni-mysore.ac.in
2006-01-15
Dispersion corrections to the forward Rayleigh scattering amplitudes of tantalum, mercury and lead in the photon energy range 24-136 keV have been determined by a numerical evaluation of the dispersion integral that relates them through optical theorem to the photo effect cross sections. The photo effect cross sections have been extracted by subtracting the coherent and incoherent scattering contribution from the measured total attenuation cross section, using high-resolution high-purity germanium detector in a narrow beam good geometry set up. The real part of the dispersion correction to which the relativistic corrections calculated by Kissel and Pratt (S-matrix approach) or Creagh and McAuley (multipole corrections) have been included are in better agreement with the available theoretical values.
Measurement of the stimulated thermal Rayleigh scattering instability
International Nuclear Information System (INIS)
Karr, T.J.; Rushford, M.C.; Murray, J.R.; Morris, J.R.
1989-04-01
Growth of perturbations due to stimulated thermal Rayleigh scattering was observed on a laser beam propagating in a 1 meter cell of CC14. Initial sinusoidal irradiance perturbations were seeded onto the laser leam, and their amplification in the cell was recorded by a near field camera. The perturbation growth rate is in agreement with analytical predictions of linearized propagation theory
Size estimates of nobel gas clusters by Rayleigh scattering experiments
Institute of Scientific and Technical Information of China (English)
Pinpin Zhu (朱频频); Guoquan Ni (倪国权); Zhizhan Xu (徐至展)
2003-01-01
Noble gases (argon, krypton, and xenon) are puffed into vacuum through a nozzle to produce clusters for studying laser-cluster interactions. Good estimates of the average size of the argon, krypton and xenon clusters are made by carrying out a series of Rayleigh scattering experiments. In the experiments, we have found that the scattered signal intensity varied greatly with the opening area of the pulsed valve. A new method is put forward to choose the appropriate scattered signal and measure the size of Kr cluster.
Resonance scattering of Rayleigh waves by a mass defect
International Nuclear Information System (INIS)
Croitoru, M.; Grecu, D.
1978-06-01
The resonance scattering of an incident Rayleigh wave by a mass defect extending over a small cylindrical region situated in the surface of a semi-infinite isotropic, elastic medium is investigated by means of the Green's function method. The form of the differential cross-section for the scattering into different channels exhibits a strong resonance phenomenon at two frequencies. The expression of the resonance frequencies as well as of the corresponding widths depends on the relative change in mass density. The main assumption that the wavelengths of incoming and scattered wave are large compared to the defect dimension implies a large relative mass-density change. (author)
What is the contribution of scattering to the Love-to-Rayleigh ratio in ambient microseismic noise?
Ziane, D.; Hadziioannou, C.
2015-12-01
Several observations show the existence of both Rayleigh and Love waves in the secondary microseism. While the Rayleigh wave excitation is well described by Longuet-Higgins, the process responsible for Love wave generation still needs further investigation. Several different mechanisms could excite Love waves in this frequency band: broadly speaking, we can differentiate between source effects, like pressure variations on the oblique sea floor, or internal effects in the medium along the propagation path, such as scattering and conversions. Here we will focus on the internal effects. We perform single scattering tests in 2D and 3D to gain a better understanding of the scattering radiation pattern and the conversion between P, S, Rayleigh and Love waves. Furthermore, we use random media with continuous variations of the elastic parameters to create a scattering regime similar to the Earths interior, e.g. Gaussian or von Karmann correlation functions. The aim is to explore the contribution of scattering along the propagation path to the observed Love to Rayleigh wave energy ratios, assuming a purely vertical force source mechanism. We use finite different solvers to calculate the synthetic seismograms, and to separate the different wave types we measure the rotational and divergent components of the wave field.
International Nuclear Information System (INIS)
Kopainsky, J.
1975-01-01
In weakly ionized plasmas the scattering of electromagnetic waves on free electrons (Thompson scattering) can be neglected as compared with the scattering on bound electrons (Rayleigh scattering). If the scattering process can be described by a fluid dynamical model it is caused by sound waves which are generated or annihilated by the incident electromagnetic wave. The propagation of sound waves results in a shift of the scattered line whereas their absorption within the plasma produces the broadening of the scattered line. The theory of propagation of sound in weakly ionized plasmas is developed and extended to Rayleigh scattering. The results are applied to laser scattering in a weakly ionized hydrogen plasma. (Auth.)
Absorption and scattering properties of arbitrarily shaped particles in the Rayleigh domain
International Nuclear Information System (INIS)
Min, M.; Hovenier, J.W.; Dominik, C.; Koter, A. de; Yurkin, M.A.
2006-01-01
We provide a theoretical foundation for the statistical approach for computing the absorption properties of particles in the Rayleigh domain. We present a general method based on the discrete dipole approximation to compute the absorption and scattering properties of particles in the Rayleigh domain. The method allows to separate the geometrical aspects of a particle from its material properties. Doing the computation of the optical properties of a particle once, provides them for any set of refractive indices, wavelengths and orientations. This allows for fast computations of e.g. absorption spectra of arbitrarily shaped particles. Other practical applications of the method are in the interpretation of atmospheric and radar measurements as well as computations of the scattering matrix of small particles as a function of the scattering angle. In the statistical approach, the optical properties of irregularly shaped particles are represented by the average properties of an ensemble of particles with simple shapes. We show that the absorption cross section of an ensemble of arbitrarily shaped particles with arbitrary orientations can always be uniquely represented by the average absorption cross section of an ensemble of spheroidal particles with the same composition and fixed orientation. This proves for the first time that the statistical approach is generally viable in the Rayleigh domain
Measurement of molecular polarizability on Rayleigh light scattering
International Nuclear Information System (INIS)
Nerushev, O.A.; Novopashin, S.A.
1994-01-01
The installation for measuring the polarizability of atoms and molecules on Rayleigh light scattering is described. The measurements in gases with the known polarizability are used for a calibration. Test measurements are carried out on nitrogen, argon, carbon dioxide, vapours of water and acetone. The results of measurements are compared with the table data. The technique is used for measuring the polarizability of fullerene molecules. 6 refs., 2 figs
International Nuclear Information System (INIS)
Itoh, Tamitake; Ozaki, Yukihiro; Yoshikawa, Hiroyuki; Ihama, Takashi; Masuhara, Hiroshi
2006-01-01
We report that hyper-Rayleigh scattering, surface-enhanced hyper-Raman scattering, and two-photon excited luminescence occur intermittently by focusing a continuous-wave near-infrared (cw-NIR) laser into a colloidal silver solution including rhodamine 6G (R6G) and sodium chloride (NaCl). On the other hand, continuous hyper-Rayleigh scattering is observed from colloidal silver free from R6G and NaCl, demonstrating that hyper-Raman scattering and two-photon excited luminescence are attributed to R6G and their intermittent features are dependent on the colloidal dispersion. These results suggest that the cw-NIR laser has three roles; the source of the nonlinear response, optical trapping of nanoparticles, and making nanoparticle aggregates possessing the high activity for the nonlinear response
Calculating Rayleigh scattering amplitudes from 100 eV to 10 MeV
International Nuclear Information System (INIS)
Parker, J.C.; Reynaud, G.W.; Botto, D.J.; Pratt, R.H.
1979-01-01
An attempt is made to explain how to calculate the contribution to elastic photon-atom scattering due to Rayleigh scattering (the scattering off bound electrons) in the photon energy range 100 eV less than or equal to W less than or equal to 10 MeV. All intermediate calculations are described, including the calculation of the potential, bound state wave functions, matrix elements, and final cross sections. 12 references
International Nuclear Information System (INIS)
Chaparian, A.; Oghabian, M. A.; Changizi, V.
2009-01-01
Recently, it has been indicated that X-ray coherent scatter from biological tissues can be used to access signature of tissue. Some scientists are interested in studying this effect to get early detection of breast cancer. Since experimental methods for optimization are time consuming and expensive, some scientists suggest using simulation. Monte Carlo codes are the best option for radiation simulation: however, one permanent defect with Monte Carlo codes has been the lack of a sufficient physical model for coherent (Rayleigh) scattering, including molecular interference effects. Materials and Methods: It was decided to obtain molecular interference functions of coherent X-ray scattering for normal breast tissues by combination of modeling and experimental methods. A Monte Carlo simulation program was written to simulate the angular distribution of scattered photons for the normal breast tissue samples. Moreover, experimental diffraction patterns of these tissues were measured by means of energy dispersive X-ray diffraction method. The simulation and experimental data were used to obtain a tabulation of molecular interference functions for breast tissues. Results: With this study a tabulation of molecular interference functions for normal breast tissues Was prepared to facilitate the simulation diffraction patterns of the tissues without any experimental. Conclusion: The method may lead to design new systems for early detection of breast cancer.
Ultraviolet Rayleigh Scatter Imaging for Spatial Temperature Profiles in Atmospheric Microdischarges
2014-09-01
approximation of Rayleigh scattering for atomic gases, such as helium and argon . 13 Approved for public release; distribution unlimited. Figure 3... polarizability tensor , as [13] = + + = + + ...22�. (25) 16 Approved for public release; distribution unlimited. To further define the polarizability
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...
Rayleigh-wave scattering by shallow cracks using the indirect boundary element method
International Nuclear Information System (INIS)
Ávila-Carrera, R; Rodríguez-Castellanos, A; Ortiz-Alemán, C; Sánchez-Sesma, F J
2009-01-01
The scattering and diffraction of Rayleigh waves by shallow cracks using the indirect boundary element method (IBEM) are investigated. The detection of cracks is of interest because their presence may compromise structural elements, put technological devices at risk or represent economical potential in reservoir engineering. Shallow cracks may give rise to scattered body and surface waves. These waves are sensitive to the crack's geometry, size and orientation. Under certain conditions, amplitude spectra clearly show conspicuous resonances that are associated with trapped waves. Several applications based on the scattering of surface waves (e.g. Rayleigh and Stoneley waves), such as non-destructive testing or oil well exploration, have shown that the scattered fields may provide useful information to detect cracks and other heterogeneities. The subject is not new and several analytical and numerical techniques have been applied for the last 50 years to understand the basis of multiple scattering phenomena. In this work, we use the IBEM to calculate the scattered fields produced by single or multiple cracks near a free surface. This method is based upon an integral representation of the scattered displacement fields, which is derived from Somigliana's identity. Results are given in both frequency and time domains. The analyses of the displacement field using synthetic seismograms and snapshots reveal some important effects from various configurations of cracks. The study of these simple cases may provide an archetype to geoscientists and engineers to understand the fundamental aspects of multiple scattering and diffraction by cracks
Coherent Raman scattering: Applications in imaging and sensing
Cui, Meng
In this thesis, I discuss the theory, implementation and applications of coherent Raman scattering to imaging and sensing. A time domain interferometric method has been developed to collect high resolution shot-noise-limited Raman spectra over the Raman fingerprint regime and completely remove the electronic background signal in coherent Raman scattering. Compared with other existing coherent Raman microscopy methods, this time domain approach is proved to be simpler and more robust in rejecting background signal. We apply this method to image polymers and biological samples and demonstrate that the same setup can be used to collect two photon fluorescence and self phase modulation signals. A signal to noise ratio analysis is performed to show that this time domain method has a comparable signal to noise ratio to spectral domain methods, which we confirm experimentally. The coherent Raman method is also compared with spontaneous Raman scattering. The conditions under which coherent methods provide signal enhancement are discussed and experiments are performed to compare coherent Raman scattering with spontaneous Raman scattering under typical biological imaging conditions. A critical power, above which coherent Raman scattering is more sensitive than spontaneous Raman scattering, is experimentally determined to be ˜1mW in samples of high molecule concentration with a 75MHz laser system. This finding is contrary to claims that coherent methods provide many orders of magnitude enhancement under comparable conditions. In addition to the far field applications, I also discuss the combination of our time domain coherent Raman method with near field enhancement to explore the possibility of sensing and near field imaging. We report the first direct time-resolved coherent Raman measurement performed on a nanostructured substrate for molecule sensing. The preliminary results demonstrate that sub 20 fs pulses can be used to obtain coherent Raman spectra from a small number
Molecular Rayleigh Scattering Diagnostic for Dynamic Temperature, Velocity, and Density Measurements
Mielke, Amy R.; Elam, Kristie A.; Sung, Chi-Jen
2006-01-01
A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 16 kHz. A high power CW laser beam is focused at a point in an air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 16 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. A low speed heated jet is used to validate the measurement of temperature fluctuations and an acoustically excited nozzle flow is studied to validate velocity fluctuation measurements. Power spectral density calculations of the property fluctuations, as well as mean and fluctuating quantities are presented. Temperature fluctuation results are compared with constant current anemometry measurements and velocity fluctuation results are compared with constant temperature anemometry measurements at the same locations.
Jagodzinski, Jeremy James
2007-12-01
The development to date of a diode-laser based velocimeter providing point-velocity-measurements in unseeded flows using molecular Rayleigh scattering is discussed. The velocimeter is based on modulated filtered Rayleigh scattering (MFRS), a novel variation of filtered Rayleigh scattering (FRS), utilizing modulated absorption spectroscopy techniques to detect a strong absorption of a relatively weak Rayleigh scattered signal. A rubidium (Rb) vapor filter is used to provide the relatively strong absorption; alkali metal vapors have a high optical depth at modest vapor pressures, and their narrow linewidth is ideally suited for high-resolution velocimetry. Semiconductor diode lasers are used to generate the relatively weak Rayleigh scattered signal; due to their compact, rugged construction diode lasers are ideally suited for the environmental extremes encountered in many experiments. The MFRS technique utilizes the frequency-tuning capability of diode lasers to implement a homodyne detection scheme using lock-in amplifiers. The optical frequency of the diode-based laser system used to interrogate the flow is rapidly modulated about a reference frequency in the D2-line of Rb. The frequency modulation is imposed on the Rayleigh scattered light that is collected from the probe volume in the flow under investigation. The collected frequency modulating Rayleigh scattered light is transmitted through a Rb vapor filter before being detected. The detected modulated absorption signal is fed to two lock-in amplifers synchronized with the modulation frequency of the source laser. High levels of background rejection are attained since the lock-ins are both frequency and phase selective. The two lock-in amplifiers extract different Fourier components of the detected modulated absorption signal, which are ratioed to provide an intensity normalized frequency dependent signal from a single detector. A Doppler frequency shift in the collected Rayleigh scattered light due to a change
International Nuclear Information System (INIS)
Antoniassi, M.; Conceição, A.L.C.; Poletti, M.E.
2014-01-01
In the present work, a tomographic technique based on Rayleigh to Compton scattering ratio (R/C) was studied using computational simulation in order to assess its application to breast cancer diagnosis. In this preliminary study, some parameters that affect the image quality were evaluated, such as: (i) energy beam, (ii) size and glandularity of the breast, and (iii) statistical count noise. The results showed that the R/C contrast increases with increasing photon energy and decreases with increasing glandularity of the sample. The statistical noise showed to be a significant parameter, although the quality of the obtained images was acceptable for a considerable range of noise level. The preliminary results suggest that the R/C tomographic technique has a potential of being applied as a complementary tool in the breast cancer diagnostic. - Highlights: ► A tomographic technique based on Rayleigh to Compton scattering ratio is proposed in order to study breast tissues. ► The Rayleigh to Compton scattering ratio technique is compared with conventional transmission technique. ► The influence of experimental parameters (energy, sample, detection system) is studied
Bisyarin, M A; Kotov, O I; Hartog, A H; Liokumovich, L B; Ushakov, N A
2017-06-01
The recently developed diffraction technique of analytical investigation of the Rayleigh backscattering produced by an incident fundamental mode in a multimode optical fiber with an arbitrary refractive index profile is supplemented by taking into account the Rayleigh scattering-loss coefficient, which could be variable within the fiber cross section. The relative changes in various radial and azimuthal modes' excitation levels, due to some typical radial dependences of this coefficient, are computed for the quadratic- and step-index fibers. It is stated that the excitation efficiency could either rise or decay for different modes. The effect of the variable Rayleigh scattering-loss coefficient is shown to be more noticeable in the fibers with a quadratic refractive index profile, whereas it is negligible in actual multimode step-index fibers.
Rayleigh-Brillouin scattering in SF6 in the kinetic regime
Wang, Yuanqing; Yu, Yin; Liang, Kun; Marques, Wilson; van de Water, Willem; Ubachs, Wim
2017-01-01
Rayleigh-Brillouin spectral profiles are measured with a laser-based scatterometry setup for a 90° scattering angle at a high signal-to-noise ratio (r.m.s. noise below 0.15% w.r.t. peak intensity) in sulfur-hexafluoride gas for pressures in the range 0.2–5 bar and for a wavelength of λ=403.0 nm. The
Lin, Jia-Hui; Tseng, Wei-Lung
2015-01-01
Detection of salt- and analyte-induced aggregation of gold nanoparticles (AuNPs) mostly relies on costly and bulky analytical instruments. To response this drawback, a portable, miniaturized, sensitive, and cost-effective detection technique is urgently required for rapid field detection and monitoring of target analyte via the use of AuNP-based sensor. This study combined a miniaturized spectrometer with a 532-nm laser to develop a laser-induced Rayleigh scattering technique, allowing the sensitive and selective detection of Rayleigh scattering from the aggregated AuNPs. Three AuNP-based sensing systems, including salt-, thiol- and metal ion-induced aggregation of the AuNPs, were performed to examine the sensitivity of laser-induced Rayleigh scattering technique. Salt-, thiol-, and metal ion-promoted NP aggregation were exemplified by the use of aptamer-adsorbed, fluorosurfactant-stabilized, and gallic acid-capped AuNPs for probing K(+), S-adenosylhomocysteine hydrolase-induced hydrolysis of S-adenosylhomocysteine, and Pb(2+), in sequence. Compared to the reported methods for monitoring the aggregated AuNPs, the proposed system provided distinct advantages of sensitivity. Laser-induced Rayleigh scattering technique was improved to be convenient, cheap, and portable by replacing a diode laser and a miniaturized spectrometer with a laser pointer and a smart-phone. Using this smart-phone-based detection platform, we can determine whether or not the Pb(2+) concentration exceed the maximum allowable level of Pb(2+) in drinking water. Copyright © 2014 Elsevier B.V. All rights reserved.
Ribosome formation from subunits studied by stopped-flow and Rayleigh light scattering
Directory of Open Access Journals (Sweden)
Antoun Ayman
2004-01-01
Full Text Available Light scattering and standard stopped-flow techniques were used to monitor rapid association of ribosomal subunits during initiation of eubacterial protein synthesis. The effects of the initiation factors IF1, IF2, IF3 and buffer conditions on subunit association were studied along with the role of GTP in this process. The part of light scattering theory that is essential for kinetic measurements is high-lighted in the main text and a more general treatment of Rayleigh scattering from macromolecules is given in an appendix.
DEFF Research Database (Denmark)
Kampel, Nir Shlomo; Griesmaier, Axel Rudolf; Steenstrup, Mads Peter Hornbak
2012-01-01
We investigate experimentally the effects of light assisted collisions on the coherence between momentum states in Bose-Einstein condensates. The onset of superradiant Rayleigh scattering serves as a sensitive monitor for matter-wave coherence. A subtle interplay of binary and collective effects...
Multiscale character of the nonlinear coherent dynamics in the Rayleigh-Taylor instability
International Nuclear Information System (INIS)
Abarzhi, S.I.; Nishihara, K.; Rosner, R.
2006-01-01
We report nonlinear solutions for a system of conservation laws describing the dynamics of the large-scale coherent structure of bubbles and spikes in the Rayleigh-Taylor instability (RTI) for fluids with a finite density ratio. Three-dimensional flows are considered with general type of symmetry in the plane normal to the direction of gravity. The nonlocal properties of the interface evolution are accounted for on the basis of group theory. It is shown that isotropic coherent structures are stable. For anisotropic structures, secondary instabilities develop with the growth rate determined by the density ratio. For stable structures, the curvature and velocity of the nonlinear bubble have nontrivial dependencies on the density ratio, yet their mutual dependence on one another has an invariant form independent of the density ratio. The process of bubble merge is not considered. Based on the obtained results we argue that the large-scale coherent dynamics in RTI has a multiscale character and is governed by two length scales: the period of the coherent structure and the bubble (spike) position
Paternò, Gianfranco; Cardarelli, Paolo; Contillo, Adriano; Gambaccini, Mauro; Taibi, Angelo
2018-01-01
Advanced applications of digital mammography such as dual-energy and tomosynthesis require multiple exposures and thus deliver higher dose compared to standard mammograms. A straightforward manner to reduce patient dose without affecting image quality would be removal of the anti-scatter grid, provided that the involved reconstruction algorithms are able to take the scatter figure into account [1]. Monte Carlo simulations are very well suited for the calculation of X-ray scatter distribution and can be used to integrate such information within the reconstruction software. Geant4 is an open source C++ particle tracking code widely used in several physical fields, including medical physics [2,3]. However, the coherent scattering cross section used by the standard Geant4 code does not take into account the influence of molecular interference. According to the independent atomic scattering approximation (the so-called free-atom model), coherent radiation is indistinguishable from primary radiation because its angular distribution is peaked in the forward direction. Since interference effects occur between x-rays scattered by neighbouring atoms in matter, it was shown experimentally that the scatter distribution is affected by the molecular structure of the target, even in amorphous materials. The most important consequence is that the coherent scatter distribution is not peaked in the forward direction, and the position of the maximum is strongly material-dependent [4]. In this contribution, we present the implementation of a method to take into account inter-atomic interference in small-angle coherent scattering in Geant4, including a dedicated data set of suitable molecular form factor values for several materials of clinical interest. Furthermore, we present scatter images of simple geometric phantoms in which the Rayleigh contribution is rigorously evaluated. Copyright © 2017.
Chen, Peili; Liu, Shaopu; Liu, Zhongfang; Hu, Xiaoli
2011-01-01
The interaction between palladium(II)-aminophylline and fluorescein sodium was investigated by resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectrum. In pH 4.4 Britton-Robinson (BR) buffer medium, aminophylline (Ami) reacted with palladium(II) to form chelate cation([Pd(Ami)]2+), which further reacted with fluorescein sodium (FS) to form ternary mixed ligand complex [Pd(Ami)(FS)2]. As a result, resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering spectrum (FDS) were enhanced. The maximum scattering wavelengths of [Pd(Ami)(FS)2] were located at 300 nm (RRS), 650 nm (SOS) and 304 nm (FDS). The scattering intensities were proportional to the Ami concentration in a certain range and the detection limits were 7.3 ng mL(-1) (RRS), 32.9 ng mL(-1) (SOS) and 79.1 ng mL(-1) (FDS), respectively. Based on it, the new simple, rapid, and sensitive scattering methods have been proposed to determine Ami in urine and serum samples. Moreover, the formation mechanism of [Pd(Ami)(FS)2] and the reasons for enhancement of RRS were fully discussed. Crown Copyright Â© 2010. Published by Elsevier B.V. All rights reserved.
Rayleigh-Brillouin scattering in NH4Cl under hydrostatic pressure
International Nuclear Information System (INIS)
Hikita, Tomoyuki; Kitabatake, Makoto; Ikeda, Takuro
1981-01-01
Rayleigh-Brillouin scattering in NH 4 Cl has been studied under hydrostatic pressure. Brillouin shifts of the longitudinal phonons propagating along the and directions and of the transverse phonons propagating along the direction are measured as a function of temperature at four fixed pressures up to 2.3 kbar. All components increase almost linearly with decreasing temperature in the disordered phase and show incremental increases similar to the temperature dependence of the long range order parameter in the ordered phase. It was found that the longitudinal modes exhibit large despersion effect even at high pressures. On the other hand, the transverse mode appears to give no dispersion effect. The intensity of the Rayleigh component in the VV polarization condition increases as the temperature approaches the transition point, while that in the VH polarization does not show such anomalous increase. (author)
On the intensity and polarization of radiation emerging from a thick Rayleigh scattering atmosphere
Directory of Open Access Journals (Sweden)
V. Natraj
2011-09-01
Full Text Available We compute the intensity and polarization of reflected and transmitted light in optically thick Rayleigh scattering atmospheres. We obtain results accurate to seven decimal places. The results have been validated using a variety of methods.
International Nuclear Information System (INIS)
Sanchez-Lara, R; Alvarez-Chavez, J A; Mendez-Martinez, F; De la Cruz-May, L; Perez-Sanchez, G G
2015-01-01
The behavior of stimulated Brillouin scattering (SBS) and Rayleigh backscattering phenomena, which limit the forward transmission power in modern, ultra-long haul optical communication systems such as dense wavelength division multiplexing systems is analyzed via simulation and experimental investigation of threshold and maximum power. Evolution of SBS, Rayleigh scattering and forward powers are experimentally investigated with a 25 km segment of single mode fiber. Also, a simple algorithm to predict the generation of SBS is proposed where two criteria of power thresholds was used for comparison with experimental data. (paper)
Directory of Open Access Journals (Sweden)
Weiwei Zhu
2013-01-01
Full Text Available The interaction of cadmium sulphide nanoparticles [(CdSn] with proteins has been studied by resonance Rayleigh scattering spectra (RRS. Below the isoelectric point, proteins such as bovine serum albumin (BSA, human serum albumin (HSA, lysozyme (Lys, hemoglobin (HGB, and ovalbumin (OVA can bind with CdSn to form macromolecules by virtue of electrostatic attraction and hydrophobic force. It can result in the enhancement of resonance Rayleigh scattering spectra (RRS intensity. Their maximum scattering peaks were 280 nm, and there was a smaller peak at 370 nm. The scattering enhancement (ΔIRRS is directly proportional to the concentration of proteins. A new RRS method for the determination of trace proteins using uncapped CdSn nanoparticles probe has been developed. The detection limits are 19.6 ng/mL for HSA, 16.7 ng/mL for BSA, 18.5 ng/mL for OVA, 80.2 ng/mL for HGB, and 67.4 ng/mL for Lys, separately. In this work, the optimum condition of reaction, the effect of foreign, and the analytical application had been investigated.
Rayleigh scattering of a cylindrical sound wave by an infinite cylinder.
Baynes, Alexander B; Godin, Oleg A
2017-12-01
Rayleigh scattering, in which the wavelength is large compared to the scattering object, is usually studied assuming plane incident waves. However, full Green's functions are required in a number of problems, e.g., when a scatterer is located close to the ocean surface or the seafloor. This paper considers the Green's function of the two-dimensional problem that corresponds to scattering of a cylindrical wave by an infinite cylinder embedded in a homogeneous fluid. Soft, hard, and impedance cylinders are considered. Exact solutions of the problem involve infinite series of products of Bessel functions. Here, simple, closed-form asymptotic solutions are derived, which are valid for arbitrary source and receiver locations outside the cylinder as long as its diameter is small relative to the wavelength. The scattered wave is given by the sum of fields of three linear image sources. The viability of the image source method was anticipated from known solutions of classical electrostatic problems involving a conducting cylinder. The asymptotic acoustic Green's functions are employed to investigate reception of low-frequency sound by sensors mounted on cylindrical bodies.
Directory of Open Access Journals (Sweden)
Konstantin A. Shapovalov
2013-01-01
Full Text Available The article considers general approach to structured particle and particle system form factor calculation in the Rayleigh-Gans-Debye (RGD approximation. Using this approach, amplitude of light scattering by a truncated pyramid and cone formulas in RGD approximation are obtained. Light scattering indicator by a truncated pyramid and cone in the RGD approximation are calculated.
International Nuclear Information System (INIS)
Kitsos, S.; Assad, A.; Diop, C.M.; Nimal, J.C.
1994-01-01
Exposure and energy absorption buildup factors for aluminum, iron, lead, and water are calculated by the SNID discrete ordinates code for an isotropic point source in a homogeneous medium. The calculation of the buildup factors takes into account the effects of both bound-electron Compton (incoherent) and coherent (Rayleigh) scattering. A comparison with buildup factors from the literature shows that these two effects greatly increase the buildup factors for energies below a few hundred kilo-electron-volts, and thus the new results are improved relative to the experiment. This greater accuracy is due to the increase in the linear attenuation coefficient, which leads to the calculation of the buildup factors for a mean free path with a smaller shield thickness. On the other hand, for the same shield thickness, exposure increases when only incoherent scattering is included and decreases when only coherent scattering is included, so that the exposure finally decreases when both effects are included. Great care must also be taken when checking the approximations for gamma-ray deep-penetration transport calculations, as well as for the cross-section treatment and origin
Rayleigh scatter in kilovoltage x-ray imaging: is the independent atom approximation good enough?
Poludniowski, G; Evans, PM; Webb, S
2009-01-01
Monte Carlo simulation is the gold standard method for modelling scattering processes in medical x-ray imaging. General-purpose Monte Carlo codes, however, typically use the independent atom approximation (IAA). This is known to be inaccurate for Rayleigh scattering, for many materials, in the forward direction. This work addresses whether the IAA is sufficient for the typical modelling tasks in medical kilovoltage x-ray imaging. As a means of comparison, we incorporate a more realistic 'inte...
Hauchecorne, A.; Blanot, L.; Wing, R., Jr.; Keckhut, P.; Khaykin, S. M.
2017-12-01
The scattering of sunlight by the Earth atmosphere above the top of the stratospheric layer, about 30-35 km altitude, is only due to Rayleigh scattering by atmospheric molecules. Its intensity is then directly proportional to the atmospheric density. It is then possible to retrieve a temperature profile in absolute value using the hydrostatic equation and the perfect gas law, assuming that the temperature is known from a climatological model at the top of the density profile. This technique is applied to Rayleigh lidar observations since more than 35 years (Hauchecorne and Chanin, 1980). The GOMOS star occultation spectrometer observed the sunlight scattering at limb during daytime to remove it from the star spectrum. In the frame of the ESA funded MesosphEO project, GOMOS Rayleigh scattering profiles in the spectral range 400-460 nm have been used to retrieve temperature profiles from 35 to 85 km with a 2-km vertical resolution. A dataset of more than 310 thousands profiles from 2002 to 2012 is available for climatology and atmospheric dynamics studies. The validation of this dataset using NDACC Rayleigh lidars and MLS-AURA and SABER-TIMED will be presented. Preliminary results on the variability of the upper stratosphere and the mesosphere will be shown. We propose to apply this technique in the future to ALTIUS observations. The Rayleigh scattering technique can be applied to any sounder observing the day-time limb on the near-UV and visible spectrum.
Experimental confirmation of neoclassical Compton scattering theory
Energy Technology Data Exchange (ETDEWEB)
Aristov, V. V., E-mail: aristov@iptm.ru [Russian Academy of Sciences, Institute of Microelectronics Technology and High Purity Materials (Russian Federation); Yakunin, S. N. [National Research Centre “Kurchatov Institute” (Russian Federation); Despotuli, A. A. [Russian Academy of Sciences, Institute of Microelectronics Technology and High Purity Materials (Russian Federation)
2013-12-15
Incoherent X-ray scattering spectra of diamond and silicon crystals recorded on the BESSY-2 electron storage ring have been analyzed. All spectral features are described well in terms of the neoclassical scattering theory without consideration for the hypotheses accepted in quantum electrodynamics. It is noted that the accepted tabular data on the intensity ratio between the Compton and Rayleigh spectral components may significantly differ from the experimental values. It is concluded that the development of the general theory (considering coherent scattering, incoherent scattering, and Bragg diffraction) must be continued.
Hyper-Rayleigh scattering in centrosymmetric systems
Energy Technology Data Exchange (ETDEWEB)
Williams, Mathew D.; Ford, Jack S.; Andrews, David L., E-mail: david.andrews@physics.org [School of Chemistry, University of East Anglia, Norwich NR4 7TJ (United Kingdom)
2015-09-28
Hyper-Rayleigh scattering (HRS) is an incoherent mechanism for optical second harmonic generation. The frequency-doubled light that emerges from this mechanism is not emitted in a laser-like manner, in the forward direction; it is scattered in all directions. The underlying theory for this effect involves terms that are quadratic in the incident field and involves an even-order optical susceptibility (for a molecule, its associated hyperpolarizability). In consequence, HRS is often regarded as formally forbidden in centrosymmetric media. However, for the fundamental three-photon interaction, theory based on the standard electric dipole approximation, representable as E1{sup 3}, does not account for all experimental observations. The relevant results emerge upon extending the theory to include E1{sup 2}M1 and E1{sup 2}E2 contributions, incorporating one magnetic dipolar or electric quadrupolar interaction, respectively, to a consistent level of multipolar expansion. Both additional interactions require the deployment of higher orders in the multipole expansion, with the E1{sup 2}E2 interaction analogous in rank and parity to a four-wave susceptibility. To elicit the correct form of response from fluid or disordered media invites a tensor representation which does not oversimplify the molecular components, yet which can produce results to facilitate the interpretation of experimental observations. The detailed derivation in this work leads to results which are summarized for the following: perpendicular detection of polarization components both parallel and perpendicular to the pump radiation, leading to distinct polarization ratio results, as well as a reversal ratio for forward scattered circular polarizations. The results provide a route to handling data with direct physical interpretation, to enable the more sophisticated design of molecules with sought nonlinear optical properties.
Directory of Open Access Journals (Sweden)
Annepu Venkata Naga Vamsi
2016-01-01
Full Text Available We have reported the measurement of temperature by using coherent anti-Stroke and coherent Stroke Raman scattering using superconducting nano wire single-photon detector. The measured temperatures by both methods (Coherent Anti-Raman scattering & Coherent Stroke Raman scattering and TC 340 are in good accuracy of ± 5 K temperature range. The length of the pipe line under test can be increased by increasing the power of the pump laser. This methodology can be widely used to measure temperatures at instantaneous positions in test pipe line or the entire temperature of the pipe line under test.
Importance sampling the Rayleigh phase function
DEFF Research Database (Denmark)
Frisvad, Jeppe Revall
2011-01-01
Rayleigh scattering is used frequently in Monte Carlo simulation of multiple scattering. The Rayleigh phase function is quite simple, and one might expect that it should be simple to importance sample it efficiently. However, there seems to be no one good way of sampling it in the literature....... This paper provides the details of several different techniques for importance sampling the Rayleigh phase function, and it includes a comparison of their performance as well as hints toward efficient implementation....
International Nuclear Information System (INIS)
Kitsos, S.; Diop, C.M.; Assad, A.; Nimal, J.C.; Ridoux, P.
1996-01-01
Improvements of gamma-ray transport calculations in S n codes aim at taking into account the bound-electron effect of Compton scattering (incoherent), coherent scattering (Rayleigh), and secondary sources of bremsstrahlung and fluorescence. A computation scheme was developed to take into account these phenomena by modifying the angular and energy transfer matrices, and no modification in the transport code has been made. The incoherent and coherent scatterings as well as the fluorescence sources can be strictly treated by the transfer matrix change. For bremsstrahlung sources, this is possible if one can neglect the charged particles path as they pass through the matter (electrons and positrons) and is applicable for the energy range of interest for us (below 10 MeV). These improvements have been reported on the kernel attenuation codes by the calculation of new buildup factors. The gamma-ray buildup factors have been carried out for 25 natural elements up to 30 mean free paths in the energy range between 15 keV and 10 MeV
International Nuclear Information System (INIS)
Hubbell, J.H.
1993-01-01
This report reviews available information on polarization effects arising when photons in the X-ray and gamma-ray energy regime undergo coherent (Rayleigh) scattering and incoherent (Compton) scattering by atomic electrons. In addition to descriptions and discussions of these effects, including estimates of their magnitudes as they apply to radiation transport calculations, an annotated bibliography of 102 selected works covering the period 1905-1991 is provided, with particularly relevant works for the purpose of this report flagged with asterisks (*). A major resource for this report is a 1948 unpublished informal report by L.V. Spencer which has been quoted here almost in its entirety, since, of all the works cited in the annotated bibliography, it appears to be the only one which explicitly and directly addresses the purpose of this report. Hence this valuable material should be re-introduced into the available and current literature. (author). 119 refs., 7 figs
Distinct Rayleigh scattering from hot spot mutant p53 proteins reveals cancer cells.
Jun, Ho Joon; Nguyen, Anh H; Kim, Yeul Hong; Park, Kyong Hwa; Kim, Doyoun; Kim, Kyeong Kyu; Sim, Sang Jun
2014-07-23
The scattering of light redirects and resonances when an electromagnetic wave interacts with electrons orbits in the hot spot core protein and oscillated electron of the gold nanoparticles (AuNP). This report demonstrates convincingly that resonant Rayleigh scattering generated from hot spot mutant p53 proteins is correspondence to cancer cells. Hot spot mutants have unique local electron density changes that affect specificity of DNA binding affinity compared with wild types. Rayleigh scattering changes introduced by hot-spot mutations were monitored by localized surface plasmon resonance (LSPR) shift changes. The LSPR λmax shift for hot-spot mutants ranged from 1.7 to 4.2 nm for mouse samples and from 0.64 nm to 2.66 nm for human samples, compared to 9.6 nm and 15 nm for wild type and mouse and human proteins, respectively with a detection sensitivity of p53 concentration at 17.9 nM. It is interesting that hot-spot mutants, which affect only interaction with DNA, launches affinitive changes as considerable as wild types. These changes propose that hot-spot mutants p53 proteins can be easily detected by local electron density alterations that disturbs the specificity of DNA binding of p53 core domain on the surface of the DNA probed-nanoplasmonic sensor. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
International Nuclear Information System (INIS)
Patkowski, A.; Fischer, E. W.; Steffen, W.; Glaser, H.; Baumann, M.; Ruths, T.; Meier, G.
2001-01-01
A new feature of glass-forming liquids, i.e., long-range density fluctuations of the order of 100 nm, has been extensively characterized by means of static light scattering, photon correlation spectroscopy and Rayleigh-Brillouin spectroscopy in orthoterphenyl (OTP) and 1,1-di(4 # prime#-methoxy-5 # prime#methyl-phenyl)-cyclohexane (BMMPC). These long-range density fluctuations result in the following unusual features observed in a light scattering experiment, which are not described by the existing theories: (i) strong q-dependent isotropic excess Rayleigh intensity, (ii) additional slow component in the polarized photon correlation function, and (iii) high Landau-Placzek ratio. These unusual features are equilibrium properties of the glass-forming liquids and depend only on temperature, provided that the sample has been equilibrated long enough. The temperature-dependent equilibration times were measured for BMMPC and are about 11 orders of magnitude longer than the α process. It was found that the glass-forming liquid OTP may occur in two states: with and without long-range density fluctuations ('clusters'). We have characterized the two states by static and dynamic light scattering in the temperature range from T g to T g +200 K. The relaxation times of the α process as well as the parameters of the Brillouin line are identical in both OTP with and without clusters. The α process (density fluctuations) in OTP was characterized by measuring either the polarized (VV) or depolarized (VH) correlation function, which are practically identical and q-independent. This feature, which is commonly observed in glass-forming liquids, is not fully explained by the existing theories
Dynamic light scattering optical coherence tomography.
Lee, Jonghwan; Wu, Weicheng; Jiang, James Y; Zhu, Bo; Boas, David A
2012-09-24
We introduce an integration of dynamic light scattering (DLS) and optical coherence tomography (OCT) for high-resolution 3D imaging of heterogeneous diffusion and flow. DLS analyzes fluctuations in light scattered by particles to measure diffusion or flow of the particles, and OCT uses coherence gating to collect light only scattered from a small volume for high-resolution structural imaging. Therefore, the integration of DLS and OCT enables high-resolution 3D imaging of diffusion and flow. We derived a theory under the assumption that static and moving particles are mixed within the OCT resolution volume and the moving particles can exhibit either diffusive or translational motion. Based on this theory, we developed a fitting algorithm to estimate dynamic parameters including the axial and transverse velocities and the diffusion coefficient. We validated DLS-OCT measurements of diffusion and flow through numerical simulations and phantom experiments. As an example application, we performed DLS-OCT imaging of the living animal brain, resulting in 3D maps of the absolute and axial velocities, the diffusion coefficient, and the coefficient of determination.
Air-mass flux measurement system using Doppler-shifted filtered Rayleigh scattering
Shirley, John A.; Winter, Michael
1993-01-01
An optical system has been investigated to measure mass flux distributions in the inlet of a high speed air-breathing propulsion system. Rayleigh scattered light from air is proportional to the number density of molecules and hence can be used to ascertain the gas density in a calibrated system. Velocity field measurements are achieved by spectrally filtering the elastically-scattered Doppler-shifted light with an absorbing molecular filter. A novel anamorphic optical collection system is used which allows optical rays from different scattering angles, that have different Doppler shifts, to be recorded separately. This is shown to obviate the need to tune the laser through the absorption to determine velocities, while retaining the ability to make spatially-resolved measurements along a line. By properly selecting the laser tuning and filter parameters, simultaneous density measurements can be made. These properties are discussed in the paper and experiments demonstrating the velocimetry capability are described.
Directory of Open Access Journals (Sweden)
Tor eNordam
2013-09-01
Full Text Available A formalism is introduced for the non-perturbative, purely numerical, solution of the reduced Rayleigh equation for the scattering of light from two-dimensional penetrable rough surfaces. Implementation and performance issues of the method, and various consistency checks of it, are presented and discussed. The proposed method is found, within the validity of the Rayleigh hypothesis, to give reliable results. For a non-absorbing metal surface the conservation of energy was explicitly checked, and found to be satisfied to within 0.03%, or better, for the parameters assumed. This testifies to the accuracy of the approach and a satisfactory discretization. As an illustration, we calculate the full angular distribution of the mean differential reflection coefficient for the scattering of p- or s-polarized light incident on two-dimensional dielectric or metallic randomly rough surfaces defined by (isotropic or anisotropic Gaussian and cylindrical power spectra. Simulation results obtained by the proposed method agree well with experimentally measured scattering data taken from similar well-characterized, rough metal samples, or to results obtained by other numerical methods.
Analytical evaluation of atomic form factors: Application to Rayleigh scattering
Energy Technology Data Exchange (ETDEWEB)
Safari, L., E-mail: laleh.safari@ist.ac.at [IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg (Austria); Department of Physics, University of Oulu, Box 3000, FI-90014 Oulu (Finland); Santos, J. P. [Laboratório de Instrumentação, Engenharia Biomédica e Física da Radiação (LIBPhys-UNL), Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Amaro, P. [Laboratório de Instrumentação, Engenharia Biomédica e Física da Radiação (LIBPhys-UNL), Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Physikalisches Institut, Universität Heidelberg, D-69120 Heidelberg (Germany); Jänkälä, K. [Department of Physics, University of Oulu, Box 3000, FI-90014 Oulu (Finland); Fratini, F. [Department of Physics, University of Oulu, Box 3000, FI-90014 Oulu (Finland); Institute of Atomic and Subatomic Physics, TU Wien, Stadionallee 2, 1020 Wien (Austria); Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG (Brazil)
2015-05-15
Atomic form factors are widely used for the characterization of targets and specimens, from crystallography to biology. By using recent mathematical results, here we derive an analytical expression for the atomic form factor within the independent particle model constructed from nonrelativistic screened hydrogenic wave functions. The range of validity of this analytical expression is checked by comparing the analytically obtained form factors with the ones obtained within the Hartee-Fock method. As an example, we apply our analytical expression for the atomic form factor to evaluate the differential cross section for Rayleigh scattering off neutral atoms.
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.
Anisotropy of relativistic lepton coherent scattering at axial channeling
International Nuclear Information System (INIS)
Telegin, V.I.; Kanloev, A.M.; Kungurov, F.R.
1989-01-01
The contribution of the coherent and incoherent scattering of relativistic leptons passed through thin crystals in the channeling mode to their angular distribution is considered. The investigation was carried out by numerical integration of the motion equations for a great number of particles. It is shown that in the crystals with a thickness smaller than the dechanneling length the determining role in formation of distribution over the axit angles is played by the coherent scattering of particles by atomic chains. The effect of the multiple scattering on the angular distribution is negligibly small. 6 refs.; 4 figs
Rayleigh theory of ultrasound scattering applied to liquid-filled contrast nanoparticles.
Flegg, M B; Poole, C M; Whittaker, A K; Keen, I; Langton, C M
2010-06-07
We present a novel modified theory based upon Rayleigh scattering of ultrasound from composite nanoparticles with a liquid core and solid shell. We derive closed form solutions to the scattering cross-section and have applied this model to an ultrasound contrast agent consisting of a liquid-filled core (perfluorooctyl bromide, PFOB) encapsulated by a polymer shell (poly-caprolactone, PCL). Sensitivity analysis was performed to predict the dependence of the scattering cross-section upon material and dimensional parameters. A rapid increase in the scattering cross-section was achieved by increasing the compressibility of the core, validating the incorporation of high compressibility PFOB; the compressibility of the shell had little impact on the overall scattering cross-section although a more compressible shell is desirable. Changes in the density of the shell and the core result in predicted local minima in the scattering cross-section, approximately corresponding to the PFOB-PCL contrast agent considered; hence, incorporation of a lower shell density could potentially significantly improve the scattering cross-section. A 50% reduction in shell thickness relative to external radius increased the predicted scattering cross-section by 50%. Although it has often been considered that the shell has a negative effect on the echogeneity due to its low compressibility, we have shown that it can potentially play an important role in the echogeneity of the contrast agent. The challenge for the future is to identify suitable shell and core materials that meet the predicted characteristics in order to achieve optimal echogenity.
Elucidating the contribution of Rayleigh scattering to the bluish appearance of veins
Van Leeuwen, Spencer R.; Baranoski, Gladimir V. G.
2018-02-01
The bluish appearance of veins located immediately beneath the skin has long been a topic of interest for biomedical optics researchers. Despite this interest, a thorough identification of the specific optical processes responsible for this phenomenon remains to be achieved. We employ controlled in silico experiments to address this enduring open problem. Our experiments, which are supported by measured data available in the scientific literature, are performed using first-principles models of light interaction with human skin and blood. Using this investigation approach, we quantitatively demonstrate that Rayleigh scattering caused by collagen fibrils present in the papillary dermis, a sublayer of the skin, can play a pivotal role in the bluish appearance of veins as suggested by previous works in this area. Moreover, also taking color perception aspects into account, we systematically assess the effects of variations in fibril radius and papillary dermis thickness on the coloration of veins under different illuminants. Notably, this assessment indicates that Rayleigh scattering elicited by reticulin fibrils, another type of fibril found in the papillary dermis, is unlikely to significantly contribute to the bluish appearance of veins. By strengthening the current understanding of light attenuation mechanisms affecting the appearance of skin and blood, our investigation contributes to the development of more effective technologies aimed at the noninvasive measurement of the physiological properties of these tissues.
International Nuclear Information System (INIS)
Stevendaal, U. van; Schlomka, J.-P.; Harding, A.; Grass, M.
2003-01-01
Coherent scatter computed tomography (CSCT) is a reconstructive x-ray imaging technique that yields the spatially resolved coherent-scatter form factor of the investigated object. Reconstruction from coherently scattered x-rays is commonly done using algebraic reconstruction techniques (ART). In this paper, we propose an alternative approach based on filtered back-projection. For the first time, a three-dimensional (3D) filtered back-projection technique using curved 3D back-projection lines is applied to two-dimensional coherent scatter projection data. The proposed algorithm is tested with simulated projection data as well as with projection data acquired with a demonstrator setup similar to a multi-line CT scanner geometry. While yielding comparable image quality as ART reconstruction, the modified 3D filtered back-projection algorithm is about two orders of magnitude faster. In contrast to iterative reconstruction schemes, it has the advantage that subfield-of-view reconstruction becomes feasible. This allows a selective reconstruction of the coherent-scatter form factor for a region of interest. The proposed modified 3D filtered back-projection algorithm is a powerful reconstruction technique to be implemented in a CSCT scanning system. This method gives coherent scatter CT the potential of becoming a competitive modality for medical imaging or nondestructive testing
Studying coherent scattering in the CP stars atmospheres
Fišák, J.; Kubát, J.; Krtička, J.
2018-01-01
Chemically peculiar stars form a very interesting class of stars which frequently show variability. The variability is probably caused by the uneven surface distribution of chemical elements. Some elements are overabundant and some elements are underabundant compared to the solar chemical composition. In the case of chemically overabundant composition some of the rare photon-atom processes can be more important than in the atmospheres of stars with solar chemical composition. We study the importance of Rayleigh scattering by helium.
Measurements of the initial density distribution of gas puff liners by using Rayleigh scattering
Energy Technology Data Exchange (ETDEWEB)
Kalinin, Yu G; Shashkov, A Yu [Kurchatov Institute, Moscow (Russian Federation)
1997-12-31
Rayleigh scattering of a laser beam in a gas jet is proposed for the measurements of initial density distribution of gas-puff liners. The scattering method has several advantages when compared with interferometry. In particular, it provides information on the local gas density, it is more sensitive, and the output data can be absolutely calibrated. Theoretical background of the method is briefly discussed in the paper and the optical setup used in real experiments is described. Imaging of the scattering object make it possible to detect detailed profiles of the investigated gas jet, as illustrated by several examples taken from the experiment. In some cases even the gas jet stratification has been observed. (J.U.). 1 tab., 3 figs., 1 ref.
Energy Technology Data Exchange (ETDEWEB)
Flanagan, Gene [North Carolina State Univ., Raleigh, NC (United States)
2016-02-17
Yttrium barium copper oxide (YBCO) coated conductors are known for their ability to operate in the superconducting state at relatively high temperatures, even above the boiling point of liquid nitrogen (77 K). When these same conductors are operated at lower temperatures, they are able to operate in much higher magnetic fields than traditional superconductors like NiTi or Nb_{3}Sn. Thus, YBCO superconducting magnets are one of the primary options for generating the high magnetic fields needed for future high energy physics devices. Due to slow quench propagation, quench detection remains one of the primary limitations to YBCO magnets. Fiber optic sensing, based upon Rayleigh scattering, has the potential for spatial resolution approaching the wavelength of light, or very fast temporal resolution at low spatial resolution, and a continuum of combinations in between. This project has studied, theoretically and experimentally, YBCO magnets and Rayleigh scattering quench detection systems to demonstrate feasibility of the systems for YBCO quench protection systems. Under this grant an experimentally validated 3D quench propagation model was used to accurately define the acceptable range of spatial and temporal resolutions for effective quench detection in YBCO magnets and to evaluate present-day and potentially improved YBCO conductors. The data volume and speed requirements for quench detection via Rayleigh scattering required the development of a high performance fiber optic based quench detection/data acquisition system and its integration with an existing voltage tap/thermo-couple based system. In this project, optical fibers are tightly co-wound into YBCO magnet coils, with the fiber on top of the conductor as turn-to-turn insulation. Local changes in the temperature or strain of the conductor are sensed by the optical fiber, which is in close thermal and mechanical contact with the conductor. Intrinsic imperfections in the fiber reflect Rayleigh
Determination of scattering structures from spatial coherence measurements.
Zarubin, A M
1996-03-01
A new method of structure determination and microscopic imaging with short-wavelength radiations (charged particles, X-rays, neutrons), based on measurements of the modulus and the phase of the degree of spatial coherence of the scattered radiation, is developed. The underlying principle of the method--transfer of structural information about the scattering potential via spatial coherence of the secondary (scattering) source of radiation formed by this potential--is expressed by the generalization of the van Cittert-Zernike theorem to wave and particle scattering [A.M. Zarubin, Opt. Commun. 100 (1993) 491; Opt. Commun. 102 (1993) 543]. Shearing interferometric techniques are proposed for implementing the above measurements; the limits of spatial resolution attainable by reconstruction of the absolute square of a 3D scattering potential and its 2D projections from the measurements are analyzed. It is shown theoretically that 3D imaging with atomic resolution can be realized in a "synthetic aperture" electron or ion microscope and that a 3D resolution of about 6 nm can be obtained with a "synthetic aperture" X-ray microscope. A proof-of-principle optical experiment is presented.
Effect of Rayleigh-scattering distributed feedback on multiwavelength Raman fiber laser generation.
El-Taher, A E; Harper, P; Babin, S A; Churkin, D V; Podivilov, E V; Ania-Castanon, J D; Turitsyn, S K
2011-01-15
We experimentally demonstrate a Raman fiber laser based on multiple point-action fiber Bragg grating reflectors and distributed feedback via Rayleigh scattering in an ~22-km-long optical fiber. Twenty-two lasing lines with spacing of ~100 GHz (close to International Telecommunication Union grid) in the C band are generated at the watt level. In contrast to the normal cavity with competition between laser lines, the random distributed feedback cavity exhibits highly stable multiwavelength generation with a power-equalized uniform distribution, which is almost independent on power.
Coherent response of a semiconductor microcavity in the strong coupling regime
Cassabois, G.; Triques, A. L. C.; Ferreira, R.; Delalande, C.; Roussignol, Ph; Bogani, F.
2000-05-01
We have studied the coherent dynamics of a semiconductor microcavity by means of interferometric correlation measurements with subpicosecond time resolution in a backscattering geometry. Evidence is brought of the resolution of a homogeneous polariton line in an inhomogeneously broadened exciton system. Surprisingly, photon-like polaritons exhibit an inhomogeneous dephasing. Moreover, we observe an unexpected stationary coherence up to 8 ps for the lower polariton branch close to resonance. All these experimental results are well reproduced within the framework of a linear dispersion theory assuming a coherent superposition of the reflectivity and resonant Rayleigh scattering signals with a well-defined relative phase.
Comparison of the GHSSmooth and the Rayleigh-Rice surface scatter theories
Harvey, James E.; Pfisterer, Richard N.
2016-09-01
The scalar-based GHSSmooth surface scatter theory results in an expression for the BRDF in terms of the surface PSD that is very similar to that provided by the rigorous Rayleigh-Rice (RR) vector perturbation theory. However it contains correction factors for two extreme situations not shared by the RR theory: (i) large incident or scattered angles that result in some portion of the scattered radiance distribution falling outside of the unit circle in direction cosine space, and (ii) the situation where the relevant rms surface roughness, σrel, is less than the total intrinsic rms roughness of the scattering surface. Also, the RR obliquity factor has been discovered to be an approximation of the more general GHSSmooth obliquity factor due to a little-known (or long-forgotten) implicit assumption in the RR theory that the surface autocovariance length is longer than the wavelength of the scattered radiation. This assumption allowed retaining only quadratic terms and lower in the series expansion for the cosine function, and results in reducing the validity of RR predictions for scattering angles greater than 60°. This inaccurate obliquity factor in the RR theory is also the cause of a complementary unrealistic "hook" at the high spatial frequency end of the predicted surface PSD when performing the inverse scattering problem. Furthermore, if we empirically substitute the polarization reflectance, Q, from the RR expression for the scalar reflectance, R, in the GHSSmooth expression, it inherits all of the polarization capabilities of the rigorous RR vector perturbation theory.
Generation of Attosecond X-Ray Pulse through Coherent Relativistic Nonlinear Thomson Scattering
Lee, K; Jeong, Y U; Lee, B C; Park, S H
2005-01-01
In contrast to some recent experimental results, which state that the Nonlinear Thomson Scattered (NTS) radiation is incoherent, a coherent condition under which the scattered radiation of an incident laser pulse by a bunch of electrons can be coherently superposed has been investigated. The Coherent Relativistic Nonlinear Thomson Scattered (C-RNTS) radiation makes it possible utilizing the ultra-short pulse nature of NTS radiation with a bunch of electrons, such as plasma or electron beams. A numerical simulation shows that a 25 attosecond X-ray pulse can be generated by irradiating an ultra-intense laser pulse of 4x10(19) W/cm2 on an ultra-thin solid target of 50 nm thickness, which is commercially available. The coherent condition can be easily extended to an electron beam from accelerators. Different from the solid target, much narrower electron beam is required for the generation of an attosecond pulse. Instead, this condition could be applied for the generation of intense Compton scattered X-rays with a...
Initial stage of cavitation in liquids and its observation by Rayleigh scattering
Energy Technology Data Exchange (ETDEWEB)
Pekker, M [Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC 20052, United States of America (United States); Shneider, M N, E-mail: m.n.shneider@gmail.com [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, United States of America (United States)
2017-06-15
A theory is developed for the initial stage of cavitation in the framework of Zel’dovich–Fisher theory of nucleation in the field of negative pressure, while taking into account the surface tension dependence on the nanopore radius. A saturation mechanism is proposed that limits the exponential dependence of the nucleation rate on the energy required to create nanopores. An estimate of the saturated density of nanopores at the nucleation stage is obtained. It is shown that Rayleigh scattering can detect nanopores arising at the initial stage of cavitation development. (paper)
Diagnostic of the Symbiotic Stars Environment by Thomson, Raman and Rayleigh Scattering Processes
Directory of Open Access Journals (Sweden)
M. Sekeráš
2015-02-01
Full Text Available Symbiotic stars are long-period interacting binaries consisting of a cool giant as the donor star and a white dwarf as the acretor. Due to acretion of the material from the giant’s stellar wind, the white dwarf becomes very hot and luminous. The circumstellar material partially ionized by the hot star, represents an ideal medium for processes of scattering. To investigate the symbiotic nebula we modeled the wide wings of the resonance lines OVI λ1032 Å, λ1038 Å and HeII λ1640 Å emission line in the spectrum of AG Dra, broadened by Thomson scattering. On the other hand, Raman and Rayleigh scattering arise in the neutral part of the circumstellar matter around the giant and provide a powerful tool to probe e.g. the ionization structure of the symbiotic systems and distribution of the neutral hydrogen atoms in the giant’s wind.
Selective Rayleigh light scattering determination of trace quercetin with silver nanoparticles
Energy Technology Data Exchange (ETDEWEB)
Usoltseva, Liliya O.; Samarina, Tatiana O. [Department of Chemistry, M.V.Lomonosov Moscow State University, 119991 GSP-1 Moscow (Russian Federation); Abramchuk, Sergei S. [Nesmeyanov Institute of Organoelement Compounds (INEOS), Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Prokhorova, Aleksandra F. [Department of Chemistry, M.V.Lomonosov Moscow State University, 119991 GSP-1 Moscow (Russian Federation); Beklemishev, Mikhail K., E-mail: mkb@analyt.chem.msu.ru [Department of Chemistry, M.V.Lomonosov Moscow State University, 119991 GSP-1 Moscow (Russian Federation)
2016-11-15
Rayleigh light scattering (RLS) is a simple technique with a high potential of sensitive determination of small organic molecules. We have found that ppb amounts of quercetin (Qu) greatly enhance the RLS of the solution of silver nanoparticles (AgNPs) stabilized with cetyltrimethylammonium bromide (CTAB) or sodium n-dodecyl sulfate (SDS). Enhancement of light scattering is observed only in the presence of an excess of AgNO{sub 3}, which implies that it is a result of nanoparticle growth; another reason for the enhanced scattering is the aggregation of AgNPs by the analyte that was confirmed by dynamic light scattering technique. The conditions were chosen for the determination of Qu in aqueous solution with the detection limits of 0.01 and 0.03 μmol L{sup −1} and linear ranges of 0.1–1.3 and 0.1–2.0 μmol L{sup −1} for SDS- and CTAB-stabilized AgNPs, respectively; the intra-day RSDs did not exceed 7%. Unexpectedly, other bioflavonoids (rutin, dihydroquercetin, and naringenin) did not change the signal of Qu and did not interfere with its determination in 1:1 M ratio (0.5 μmol L{sup −1} each). Other compounds (asparagin, uric acid, urea and some inorganic ions) were also tolerated in high amounts. - Highlights: • Low concentrations of quercetin enhance the light scattering by silver nanoparticles. • Main processes are aggregation, nanoparticle growth and formation of new particles. • Other compounds exert a weaker effect on the light scattering signal.
Coherent scattering of electromagnetic radiation by a polarized particle system
International Nuclear Information System (INIS)
Agre, M.Ya.; Rapoport, L.P.
1996-01-01
The paper deals with the development of the theory of coherent scattering of electromagnetic waves by a polarized atom or molecular system. Peculiarities of the angular distribution and polarization peculiarities of scattered radiation are discussed
Charge coupled devices for detection of coherent neutrino-nucleus scattering
Energy Technology Data Exchange (ETDEWEB)
Fernandez Moroni, Guillermo; Estrada, Juan; Paolini, Eduardo E.; Cancelo, Gustavo; Tiffenberg, Javier; Molina, Jorge
2015-04-01
In this article the feasibility of using charge coupled devices (CCD) to detect low-energy neutrinos through their coherent scattering with nuclei is analyzed. The detection of neutrinos through this standard model process has been elusive because of the small energy deposited in such interaction. Typical particle detectors have thresholds of a few keV, and most of the energy deposition expected from coherent scattering is well below this level. The CCD detectors discussed in this paper can operate at a threshold of approximately 30 eV, making them ideal for observing this signal. On a CCD array of 500 g located next to a power nuclear reactor the number of coherent scattering events expected is about 3000 events/year. Our results shows that a detection with a confidence level of 99% can be reached within 16 days of continuous operation; with the current 52 g detector prototype this time lapse extends to five months.
Ultrafast interfeometric investigation of resonant secondary emission from quantum well excitons
DEFF Research Database (Denmark)
Birkedal, Dan; Shah, Jagdeep; Pfeiffer, L. N.
1999-01-01
Coherent Rayleigh scattering and incoherent luminescence comprise the secondary emission from quantum well exciton following ultrafast resonant excitation. We show that coherent Rayleigh scattering forms a time-dependent speckle pattern and isolate in a single speckle the Rayleigh component from...
Energy Technology Data Exchange (ETDEWEB)
Castro, C.R.F. [Nuclear Instrumentation Laboratory-COPPE/UFRJ, P.O. Box 68509, Rio de Janeiro 21945-970 (Brazil); Barroso, R.C. [Physics Institute-University of Rio de Janeiro State, Rio de Janeiro 20559-900 (Brazil)]. E-mail: cely@uerij.br; Oliveira, L.F. de [Physics Institute-University of Rio de Janeiro State, Rio de Janeiro 20559-900 (Brazil); Lopes, R.T. [Nuclear Instrumentation Laboratory-COPPE/UFRJ, P.O. Box 68509, Rio de Janeiro 21945-970 (Brazil)
2005-08-11
The angular distribution of coherent scatter (low-momentum transfer) carries information about atomic structures, resulting in a pattern, which can be used to reconstruct a series of images. Coherent-scatter computed tomography is a novel imaging method developed to produce cross-sectional images based on the X-ray diffraction properties of an object. A different approach to coherent X-ray imaging is possible by fixing the detector at a given scatter angle {theta}, which produces an interference peak and then, carried out a tomography in the standard way. The cross-sectional images obtained allow determining the spatial dependence of coherent scatter cross-section of selected volume elements of inhomogeneous, extend objects for a single predetermined value of {theta} of interest, leading to a simplification of the data processing and the complexity of the apparatus. This work presents preliminary coherent scattering images carried out at the X-ray Diffraction beamline of the National Synchrotron Light Laboratory in Campinas, Brazil. The specimens were excised human breast tissues fixed in formaline. No frozen procedure was used in order to minimize preferred orientation during sample preparation. About 1mm thick slices cut from each of the fresh samples were mounted in frames without windows and placed on a translator to allow acquisition of scattering spectra. Cylinders containing healthy and cancerous (infiltrating ductal carcinoma) breast tissues were imagined at the characteristic angle for adipose tissue. Transmission and coherent scatter images are compared.
Three-dimensional reciprocal space x-ray coherent scattering tomography of two-dimensional object.
Zhu, Zheyuan; Pang, Shuo
2018-04-01
X-ray coherent scattering tomography is a powerful tool in discriminating biological tissues and bio-compatible materials. Conventional x-ray scattering tomography framework can only resolve isotropic scattering profile under the assumption that the material is amorphous or in powder form, which is not true especially for biological samples with orientation-dependent structure. Previous tomography schemes based on x-ray coherent scattering failed to preserve the scattering pattern from samples with preferred orientations, or required elaborated data acquisition scheme, which could limit its application in practical settings. Here, we demonstrate a simple imaging modality to preserve the anisotropic scattering signal in three-dimensional reciprocal (momentum transfer) space of a two-dimensional sample layer. By incorporating detector movement along the direction of x-ray beam, combined with a tomographic data acquisition scheme, we match the five dimensions of the measurements with the five dimensions (three in momentum transfer domain, and two in spatial domain) of the object. We employed a collimated pencil beam of a table-top copper-anode x-ray tube, along with a panel detector to investigate the feasibility of our method. We have demonstrated x-ray coherent scattering tomographic imaging at a spatial resolution ~2 mm and momentum transfer resolution 0.01 Å -1 for the rotation-invariant scattering direction. For any arbitrary, non-rotation-invariant direction, the same spatial and momentum transfer resolution can be achieved based on the spatial information from the rotation-invariant direction. The reconstructed scattering profile of each pixel from the experiment is consistent with the x-ray diffraction profile of each material. The three-dimensional scattering pattern recovered from the measurement reveals the partially ordered molecular structure of Teflon wrap in our sample. We extend the applicability of conventional x-ray coherent scattering tomography to
Exact Rayleigh scattering calculations for use with the Nimbus-7 Coastal Zone Color Scanner
Gordon, Howard R.; Brown, James W.; Evans, Robert H.
1988-01-01
The radiance reflected from a plane-parallel atmosphere and flat sea surface in the absence of aerosols has been determined with an exact multiple scattering code to improve the analysis of Nimbus-7 CZCS imagery. It is shown that the single scattering approximation normally used to compute this radiance can result in errors of up to 5 percent for small and moderate solar zenith angles. A scheme to include the effect of variations in the surface pressure in the exact computation of the Rayleigh radiance is discussed. The results of an application of these computations to CZCS imagery suggest that accurate atmospheric corrections can be obtained for solar zenith angles at least as large as 65 deg.
Coherence factors in a high-tc cuprate probed by quasi-particle scattering off vortices.
Hanaguri, T; Kohsaka, Y; Ono, M; Maltseva, M; Coleman, P; Yamada, I; Azuma, M; Takano, M; Ohishi, K; Takagi, H
2009-02-13
When electrons pair in a superconductor, quasi-particles develop an acute sensitivity to different types of scattering potential that is described by the appearance of coherence factors in the scattering amplitudes. Although the effects of coherence factors are well established in isotropic superconductors, they are much harder to detect in their anisotropic counterparts, such as high-superconducting-transition-temperature cuprates. We demonstrate an approach that highlights the momentum-dependent coherence factors in Ca2-xNaxCuO2Cl2. We used Fourier-transform scanning tunneling spectroscopy to reveal a magnetic-field dependence in quasi-particle scattering interference patterns that is sensitive to the sign of the anisotropic gap. This result is associated with the d-wave coherence factors and quasi-particle scattering off vortices. Our technique thus provides insights into the nature of electron pairing as well as quasi-particle scattering processes in unconventional superconductors.
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
Coherence effects in deep inelastic scattering
International Nuclear Information System (INIS)
Andersson, B.; Gustafson, G.; Loennblad, L.; Pettersson, U.
1988-09-01
We present a framework for deep inelastic scattering, with bound state properties in accordance with a QCD force field acting like a vortex line in a colour superconducting vacuum, which implies some simple coherence effects. Within this scheme one may describe the results of present energies very well, but one obtains an appreciable depletion of gluon radiation in the HERA energy regime. (authors)
Studies of coherent/Compton scattering method for bone mineral content measurement
International Nuclear Information System (INIS)
Sakurai, Kiyoko; Iwanami, Shigeru; Nakazawa, Keiji; Matsubayashi, Takashi; Imamura, Keiko.
1980-01-01
A measurement of bone mineral content by a coherent/Compton scattering method was described. A bone sample was irradiated by a collimated narrow beam of 59.6 keV gamma-rays emitted from a 300 mCi 241 Am source, and the scattered radiations were detected using a collimated pure germanium detector placed at 90 0 to the incident beam. The ratio of coherent to Compton peaks in a spectrum of the scattered radiations depends on the bone mineral content of the bone sample. The advantage of this method is that bone mineral content of a small region in a bone can be accurately measured. Assuming that bone consists of two components, protein and bone mineral, and that the mass absorption coefficient for Compton scattering is independent of material, the coherent to Compton scattering ratio is linearly related to the percentage in weight of bone mineral. A calibration curve was obtained by measuring standard samples which were mixed with Ca 3 (PO 4 ) 2 and H 2 O. The error due to the assumption about the mass absorption coefficient for Compton scattering and to the difference between true bone and standard samples was estimated to be less than 3% within the range from 10 to 60% in weight of bone mineral. The fat in bone affects an estimated value by only 1.5% when it is 20% in weight. For the clinical application of this method, the location to be analyzed should be selected before the measurement with two X-ray images viewed from the source and the detector. These views would be also used to correct the difference in absorption between coherent and Compton scattered radiations whose energies are slightly different from each other. The absorbed dose to the analyzed region was approximately 150 mrad. The time required for one measurement in this study was about 10 minutes. (author)
International Nuclear Information System (INIS)
Burgess, D.D.
1985-01-01
The possibilities of applying optical scattering techniques to the determination of H - concentrations in plasma sources relevant to negative ion beam generation are considered. Rayleigh scattering measurements for incident wavelengths just below the H - photoionization limit appear to be only just feasible experimentally. A more promising possibility is observation of the modification in a plasma containing negative ions of the collective ion-feature in Thomson scattering. Numerical predictions of the effects of H - concentration on the spectral distribution of the ion-feature are presented. (author)
X-ray coherent scattering tomography of textured material (Conference Presentation)
Zhu, Zheyuan; Pang, Shuo
2017-05-01
Small-angle X-ray scattering (SAXS) measures the signature of angular-dependent coherently scattered X-rays, which contains richer information in material composition and structure compared to conventional absorption-based computed tomography. SAXS image reconstruction method of a 2 or 3 dimensional object based on computed tomography, termed as coherent scattering computed tomography (CSCT), enables the detection of spatially-resolved, material-specific isotropic scattering signature inside an extended object, and provides improved contrast for medical diagnosis, security screening, and material characterization applications. However, traditional CSCT methods assumes materials are fine powders or amorphous, and possess isotropic scattering profiles, which is not generally true for all materials. Anisotropic scatters cannot be captured using conventional CSCT method and result in reconstruction errors. To obtain correct information from the sample, we designed new imaging strategy which incorporates extra degree of detector motion into X-ray scattering tomography for the detection of anisotropic scattered photons from a series of two-dimensional intensity measurements. Using a table-top, narrow-band X-ray source and a panel detector, we demonstrate the anisotropic scattering profile captured from an extended object and the reconstruction of a three-dimensional object. For materials possessing a well-organized crystalline structure with certain symmetry, the scatter texture is more predictable. We will also discuss the compressive schemes and implementation of data acquisition to improve the collection efficiency and accelerate the imaging process.
Cui, Zhiping; Hu, Xiaoli; Liu, Shaopu; Liu, Zhongfang
2011-12-01
A dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) method was developed to detect chondroitin sulfate (CS) with nile blue sulfate (NBS). At pH 3.0-4.0 Britton-Robinson (BR) buffer medium, CS interacted with NBS to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS), second order scattering (SOS) and frequence doubling scattering (FDS) appeared and their intensities were enhanced greatly. Their maximum wavelengths were located at 303 nm (RRS), 362 nm (RRS), 588 nm (SOS) and 350 nm (FDS), respectively. The scattering intensities of the three methods were proportional to the concentration of CS in certain ranges. The methods had high sensitivity and the detection limits were between 1.5 and 7.1 ng mL -1. The DWO-RRS method had the highest sensitivity with the detection limit being 1.5 ng mL -1. The characteristics of the spectra and optimal reaction conditions of RRS method were investigated. The effects of coexistent substances on the determination of CS were evaluated. Owing to the high sensitivity, RRS method had been applied to the determination of CS in eye drops with satisfactory results. The recovery range was between 99.4% and 104.6% and the relative standard deviation (RSD) was between 0.4% and 0.8%. In addition, the reasons for RRS enhancement were discussed and the shape of ion-association complex was characterized by atomic force microscopy (AFM).
The interpretation of polycrystalline coherent inelastic neutron scattering from aluminium
Roach, Daniel L.; Ross, D. Keith; Gale, Julian D.; Taylor, Jon W.
2013-01-01
A new approach to the interpretation and analysis of coherent inelastic neutron scattering from polycrystals (poly-CINS) is presented. This article describes a simulation of the one-phonon coherent inelastic scattering from a lattice model of an arbitrary crystal system. The one-phonon component is characterized by sharp features, determined, for example, by boundaries of the (Q, ω) regions where one-phonon scattering is allowed. These features may be identified with the same features apparent in the measured total coherent inelastic cross section, the other components of which (multiphonon or multiple scattering) show no sharp features. The parameters of the model can then be relaxed to improve the fit between model and experiment. This method is of particular interest where no single crystals are available. To test the approach, the poly-CINS has been measured for polycrystalline aluminium using the MARI spectrometer (ISIS), because both lattice dynamical models and measured dispersion curves are available for this material. The models used include a simple Lennard-Jones model fitted to the elastic constants of this material plus a number of embedded atom method force fields. The agreement obtained suggests that the method demonstrated should be effective in developing models for other materials where single-crystal dispersion curves are not available. PMID:24282332
Optimization of a coherent soft x-ray beamline for coherent scattering experiments at NSLS-II
Energy Technology Data Exchange (ETDEWEB)
Shapiro D.; Chubar, O.; Kaznatcheev, K.; Reininger, R.; Sanchez-Hanke, C.; Wang, S.
2011-08-21
The coherent soft x-ray and full polarization control (CSX) beamline at the National Synchrotron Light Source - II (NSLS-II) will deliver 1013 coherent photons per second in the energy range of 0.2-2 keV with a resolving power of 2000. The source, a dual elliptically polarizing undulator (EPU), and beamline optics should be optimized to deliver the highest possible coherent flux in a 10-30 {micro}m spot for use in coherent scattering experiments. Using the computer code Synchrotron Radiation Workshop (SRW), we simulate the photon source and focusing optics in order to investigate the conditions which provide the highest usable coherent intensity on the sample. In particular, we find that an intermediate phasing magnet is needed to correct for the relative phase between the two EPUs and that the optimum phase setting produces a spectrum in which the desired wavelength is slightly red-shifted thus requiring a larger aperture than originally anticipated. This setting is distinct from that which produces an on-axis spectrum similar to a single long undulator. Furthermore, partial coherence calculations, utilizing a multiple electron approach, indicate that a high degree of spatial coherence is still obtained at the sample location when such an aperture is used. The aperture size which maximizes the signal-to-noise ratio of a double-slit experiment is explored. This combination of high coherence and intensity is ideally suited for x-ray ptychography experiments which reconstruct the scattering density from micro-diffraction patterns. This technique is briefly reviewed and the effects on the image quality of proximity to the beamline focus are explored.
International Nuclear Information System (INIS)
Lu, Yao; Huang, Xiangyi; Ren, Jicun
2013-01-01
We describe a sensitive sandwich immunoassay for alpha-fetoprotein (AFP). It is making use of gold nanoparticles (GNPs) and magnetic beads (MBs) as labels, and of resonance Rayleigh scattering for detection. Two antibodies were labeled with GNPs and MBs, respectively, and MB-antigen-GNP complexes were formed in the presence of antigens. The MB labels also serve as solid phase carriers that can be used to magnetically separate the immuno complex. The GNP labels are used as optical probes, and Rayleigh scattering was used to determine the concentration of free GNPs-antibody after separation of the MB-antigen-GNP complexes. The concentration of AFP is related to the intensity of light scattered by free GNPs in the 13.6 pM to 436 pM concentration range, and the limit of detection is 13.6 pM. The method was applied to the determination of AFP in sera of cancer patients, and the results agree well with those obtained by conventional ELISA. (author)
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.
Neutron scattering in disordered alloys: coherent and incoherent intensities
International Nuclear Information System (INIS)
Mookerjee, A.; Yussouff, M.
1985-02-01
A priori it is not clear how to split the total intensity of thermal neutron scattering from disordered alloys into a coherent and an incoherent part. We present here a formalism to do this. The formalism is based on the augmented space technique introduced earlier by one of the authors. It includes disorder in mass, force constants and scattering lengths. A self-consistent CCPA which is tractable for realistic calculations is presented for the coherent and incoherent intensities. This is expected to prove useful in theoretically analysis data for alloys (e.g. Nisub(x)Ptsub(1-x), Nisub(x)Pdsub(1-x), Nisub(x)Crsub(1-x)) for which it is necessary to go beyond the usual single site CPAs for reliable accuracy. (author)
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.
Delayed coherent quantum feedback from a scattering theory and a matrix product state perspective
Guimond, P.-O.; Pletyukhov, M.; Pichler, H.; Zoller, P.
2017-12-01
We study the scattering of photons propagating in a semi-infinite waveguide terminated by a mirror and interacting with a quantum emitter. This paradigm constitutes an example of coherent quantum feedback, where light emitted towards the mirror gets redirected back to the emitter. We derive an analytical solution for the scattering of two-photon states, which is based on an exact resummation of the perturbative expansion of the scattering matrix, in a regime where the time delay of the coherent feedback is comparable to the timescale of the quantum emitter’s dynamics. We compare the results with numerical simulations based on matrix product state techniques simulating the full dynamics of the system, and extend the study to the scattering of coherent states beyond the low-power limit.
International Nuclear Information System (INIS)
Bell, H.G.
1976-07-01
The energy spectra of Ne studied under different temperatures and pressures with the aid of inelastic, coherent neutron scattering can be described by a scattering law derived from the basic hydrodynamic equations. The Brillouin lines found with very small momentum transfer 0.06 A -1 -1 are interpreted as collective, adiabatic pressure fluctuations. (orig./WL) [de
International Nuclear Information System (INIS)
Goodman, F.O.
1977-01-01
A rigorous treatment of the scattering of atoms by a stationary sinusoidal hard wall in (n+1) dimensions is presented, a previous treatment by Masel, Merrill, and Miller for n=1 being contained as a special case. Numerical comparisons are made with the GR method of Garcia, which incorporates the Rayleigh hypothesis. Advantages and disadvantages of both methods are discussed, and it is concluded that the Rayleigh GR method, if handled properly, will probably work satisfactorily in physically realistic cases
Rayleigh scatter in kilovoltage x-ray imaging: is the independent atom approximation good enough?
Poludniowski, G.; Evans, P. M.; Webb, S.
2009-11-01
Monte Carlo simulation is the gold standard method for modelling scattering processes in medical x-ray imaging. General-purpose Monte Carlo codes, however, typically use the independent atom approximation (IAA). This is known to be inaccurate for Rayleigh scattering, for many materials, in the forward direction. This work addresses whether the IAA is sufficient for the typical modelling tasks in medical kilovoltage x-ray imaging. As a means of comparison, we incorporate a more realistic 'interference function' model into a custom-written Monte Carlo code. First, we conduct simulations of scatter from isolated voxels of soft tissue, adipose, cortical bone and spongiosa. Then, we simulate scatter profiles from a cylinder of water and from phantoms of a patient's head, thorax and pelvis, constructed from diagnostic-quality CT data sets. Lastly, we reconstruct CT numbers from simulated sets of projection images and investigate the quantitative effects of the approximation. We show that the IAA can produce errors of several per cent of the total scatter, across a projection image, for typical x-ray beams and patients. The errors in reconstructed CT number, however, for the phantoms simulated, were small (typically < 10 HU). The IAA can therefore be considered sufficient for the modelling of scatter correction in CT imaging. Where accurate quantitative estimates of scatter in individual projection images are required, however, the appropriate interference functions should be included.
Collective Excitations in Liquid Hydrogen Observed by Coherent Neutron Scattering
DEFF Research Database (Denmark)
da Costa Carneiro, Kim; Nielsen, M.; McTague, J. P.
1973-01-01
Coherent scattering of neutrons by liquid parahydrogen shows the existence of well-defined collective excitations in this liquid. Qualitative similarity with the scattering from liquid helium is found. Furthermore, in the range of observed wave vectors, 0.7 Å-1 ≤κ≤3.1 Å-1, extending from the firs...
TH-AB-209-10: Breast Cancer Identification Through X-Ray Coherent Scatter Spectral Imaging
Energy Technology Data Exchange (ETDEWEB)
Kapadia, A; Morris, R; Albanese, K; Spencer, J; McCall, S; Greenberg, J [Duke University, Durham, NC (United States)
2016-06-15
Purpose: We have previously described the development and testing of a coherent-scatter spectral imaging system for identification of cancer. Our prior evaluations were performed using either tissue surrogate phantoms or formalin-fixed tissue obtained from pathology. Here we present the first results from a scatter imaging study using fresh breast tumor tissues obtained through surgical excision. Methods: A coherent-scatter imaging system was built using a clinical X-ray tube, photon counting detectors, and custom-designed coded-apertures. System performance was characterized using calibration phantoms of biological materials. Fresh breast tumors were obtained from patients undergoing mastectomy and lumpectomy surgeries for breast cancer. Each specimen was vacuum-sealed, scanned using the scatter imaging system, and then sent to pathology for histological workup. Scatter images were generated separately for each tissue specimen and analyzed to identify voxels containing malignant tissue. The images were compared against histological analysis (H&E + pathologist identification of tumors) to assess the match between scatter-based and histological diagnosis. Results: In all specimens scanned, the scatter images showed the location of cancerous regions within the specimen. The detection and classification was performed through automated spectral matching without the need for manual intervention. The scatter spectra corresponding to cancer tissue were found to be in agreement with those reported in literature. Inter-patient variability was found to be within limits reported in literature. The scatter images showed agreement with pathologist-identified regions of cancer. Spatial resolution for this configuration of the scanner was determined to be 2–3 mm, and the total scan time for each specimen was under 15 minutes. Conclusion: This work demonstrates the utility of coherent scatter imaging in identifying cancer based on the scatter properties of the tissue. It
Rayleigh-Brillouin scattering in SF6 in the kinetic regime
Wang, Yuanqing; Yu, Yin; Liang, Kun; Marques, Wilson; van de Water, Willem; Ubachs, Wim
2017-02-01
Rayleigh-Brillouin spectral profiles are measured with a laser-based scatterometry setup for a 90° scattering angle at a high signal-to-noise ratio (r.m.s. noise below 0.15% w.r.t. peak intensity) in sulfur-hexafluoride gas for pressures in the range 0.2-5 bar and for a wavelength of λ = 403.0 nm. The high quality data are compared to a number of light scattering models in order to address the effects of rotational and vibrational relaxation. While the vibrational relaxation rate is so slow that vibration degrees of freedom remain frozen, rotations relax on time scales comparable to those of the density fluctuations. Therefore, the heat capacity, the thermal conductivity and the bulk viscosity are all frequency-dependent transport coefficients. This is relevant for the Tenti model that depends on the values chosen for these transport coefficients. This is not the case for the other two models considered: a kinetic model based on rough-sphere interactions, and a model based on fluctuating hydrodynamics. The deviations with the experiment are similar between the three different models, except for the hydrodynamic model at pressures p≲ 2bar . As all models are in line with the ideal gas law, we hypothesize the presence of real gas effects in the measured spectra.
Creating von Laue patterns in crystal scattering with partially coherent sources
Wang, Y.Y.D.; Kuebel, D.; Visser, T.D.; Wolf, E.
2016-01-01
When spatially coherent radiation is diffracted by a crystalline object, the field is scattered in specific directions, giving rise to so-called von Laue patterns. We examine the role of spatial coherence in this process. Using the first-order Born approximation, a general analytic expression for
Rayleigh scattering of x-ray and {gamma}-ray by 1s and 2s electrons in ions and neutral atoms
Energy Technology Data Exchange (ETDEWEB)
Costescu, A; Karim, K; Stoica, C [Department of Physics, University of Bucharest, MG11, Bucharest-Magurele 077125 (Romania); Moldovan, M [Department of Physics, UMF Targu Mures, Targu Mures 540142 (Romania); Spanulescu, S, E-mail: severspa2004@yahoo.com [Department of Physics, Hyperion University of Bucharest, Bucharest 030629 (Romania)
2011-02-28
Using the Coulomb-Green function method and considering the nonrelativistic limit for the two-photon S-matrix element, the right nonrelativistic 2s Rayleigh scattering amplitudes are obtained. Our result takes into account all multipoles, retardation and relativistic kinematics contributions, and the old dipole approximation result of Costescu is retrieved as a limit case. The total photoeffect cross-section which is related to the imaginary part of the Rayleigh forward scattering amplitude through the optical theorem is also obtained. Our Coulombian formulae are used in the more realistic case of elastic scattering of photons by bound 1s and 2s electrons in ions and neutral atoms. Screening effects are considered in the independent particle approximation through the Hartree-Fock method. The effective charge Z{sub eff} is obtained by fitting the Hartree-Fock charge distribution by a Coulombian one. Good agreement (within 10%) is found when comparing the numerical predictions given by our nonrelativistic formulae with the full relativistic numerical results of Kissel in the case of elastic scattering of photons by 1s and 2s electrons and Scofield [3] in the case of K-shell and 2s subshell photoionization for neutral atoms with 18 {<=} Z {<=} 92 and photon energies {omega} {<=} {alpha}Zm.
Directory of Open Access Journals (Sweden)
Jingjuan Liao
2015-07-01
Full Text Available We developed a polarimetric coherent electromagnetic scattering model for Poyang Lake wetland vegetation. Realistic canopy structures including curved leaves and the lodging situation of the vegetation were taken into account, and the situation at the ground surface was established using an Advanced Integral Equation Model combined with Oh’s 2002 model. This new model can reasonably describe the coherence effect caused by the phase differences of the electromagnetic fields scattered from different particles by different scattering mechanisms. We obtained good agreement between the modeling results and C-band data from the Radarsat-2 satellite. A simulation of scattering from the vegetation in Poyang Lake showed that direct vegetation scattering and the single-ground-bounce mechanism are the dominant scattering mechanisms in the C-band and L-band, while the effects of the double-ground-bounce mechanism are very small. We note that the curvature of the leaves and the lodging characteristics of the vegetation cannot be ignored in the modeling process. Monitoring soil moisture in the Poyang Lake wetland with the C-band data was not feasible because of the density and depth of Poyang Lake vegetation. When the density of Poyang Lake Carex increases, the backscattering coefficient either decreases or remains stable.
DEFF Research Database (Denmark)
Langbein, Wolfgang Werner; Hvam, Jørn Märcher
2002-01-01
The directional dynamics of the resonant Rayleigh scattering from a semiconductor microcavity is investigated. When optically exciting the lower polariton branch, the strong dispersion results in a directional emission on a ring. The coherent emission ring shows a reduction of its angular width...... for increasing time after excitation, giving direct evidence for the time-energy uncertainty in the dynamics of the scattering by disorder. The ring width converges with time to a finite value, a direct measure of an intrinsic momentum broadening of the polariton states localized by multiple disorder scattering....
Directory of Open Access Journals (Sweden)
D. L. Hysell
2004-09-01
Full Text Available Common-volume observations of sporadic E-layers made on 14-15 June 2002 with the Arecibo incoherent scatter radar and a 30MHz coherent scatter radar imager located on St. Croix are described. Operating in dual-beam mode, the Arecibo radar detected a slowly descending sporadic E-layer accompanied by a series of dense E-region plasma clouds at a time when the coherent scatter radar was detecting quasi-periodic (QP echoes. Using coherent radar imaging, we collocate the sources of the coherent scatter with the plasma clouds observed by Arecibo. In addition to patchy, polarized scattering regions drifting through the radar illuminated volume, which have been observed in previous imaging experiments, the 30MHz radar also detected large-scale electrostatic waves in the E-region over Puerto Rico, with a wavelength of about 30km and a period of about 10min, propagating to the southwest. Both the intensity and the Doppler shifts of the coherent echoes were modulated by the wave.
Incoherent imaging using dynamically scattered coherent electrons
International Nuclear Information System (INIS)
Nellist, P.D.; Pennycook, S.J.
1999-01-01
We use a Bloch wave approach to show that, even for coherent dynamical scattering from a stationary lattice with no absorption, annular dark-field imaging in a scanning transmission electron microscope gives a direct incoherent structure image of the atomic-column positions of a zone-axis-aligned crystal. Although many Bloch waves may be excited by the probe, the detector provides a filtering effect so that the 1s-type bound states are found to dominate the image contrast for typical experimental conditions. We also find that the column intensity is related to the transverse kinetic energy of the 1s states, which gives atomic number, Z, contrast. The additional effects of phonon scattering are discussed, in particular the reasons why phonon scattering is not a prerequisite for transverse incoherence. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)
International Nuclear Information System (INIS)
Lu Jianfeng; Liu Meng; Han Jifeng; Li Jia; Luo Xiaobing; Miao Jingwei; Yang Chaowen
2009-01-01
In the experiments of Rayleigh scattering of gas-jet clusters, the signal amplitude of PMT is not only affected by duster itself, but also by the intensity of light source and work voltage of PMT. When the back pressure of cluster source varies from 10 atm to about 100atm, the signal amplitude of PMT may be from linear to nonlinear. In order to solve the problem, signal calibration of PMT under different intensifies of light and voltage of PMT has been done. The relationship between the amplitude of signal and intensities of light as well as voltage of PMT has been obtained. The function of scatter factor of Ar clusters with the back pressure of cluster source is gotten experimentally, and agrees with related experimental and theoretical results. (authors)
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)
Coherence effects in radiative scattering
International Nuclear Information System (INIS)
Knoll, J.; Lenk, R.
1993-03-01
The bremsstrahl-production of photons in dense matter is reinvestigated using the example of an exactly solvable quantum mechanical model in one space dimension. Coherence phenomena between successive radiative scatterings among the constituents lead to a modification of the production cross section in the medium relative to the incoherent quasi-free prescription used in kinetic models. Analytic expressions for the correction factor have been derived comparing the quantum rates with the corresponding incoherent quasi-free rates. The result has implications for the kinetic description of all kinds of radiative processes in nucleus-nucleus collisions, both on the level of hadron and parton dynamics. (orig.)
Rayleigh scattering of Moessbauer radiation in superionic conductor RbAg4I5
International Nuclear Information System (INIS)
Ovanesyan, N.S.; Goffman, V.G.; Sokolov, V.B.; Tkachev, V.V.
1984-01-01
The dynamical properties of RbAg 4 I 5 has been investiaated by Rayleigh scattering of Moessbauer radiation (RSMR) with wave-length lambda = 0.86 A. The character of Ag + ion oscillatory motion and diffusion in RbAg 4 I 5 depending on temperature including the phase transitions region is studied. It is shown that in the superionic crystal RbAg 4 I 5 the diffusion process is strongly correlated, i.e. a great number of initial and final states at diffusion jumps coincides. The observed broadening can be less than the expected one by value orders. Diffusion correlation can strongly reduce the activation barrier and lead to anomalously high ionic conduction
Molecular Rayleigh Scattering Diagnostic for Measurement of High Frequency Temperature Fluctuations
Mielke, Amy F.; Elam, Kristie A.
2005-01-01
A novel technique for measurement of high frequency temperature fluctuations in unseeded gas flows using molecular Rayleigh scattering is investigated. The spectrum of laser light scattered from molecules in a gas flow is resolved using a Fabry-Perot interferometer. The width of the spectral peak is broadened by thermal motion of the molecules and hence is related to gas temperature. The interference fringe pattern containing spectral information is divided into four concentric regions using a series of mirrors angled with respect to one another. Light from each of these regions is directed towards photomultiplier tubes and sampled at 10 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows measurement of gas temperature. Independently monitoring the total scattered intensity provides a measure of gas density. This technique also has the potential to simultaneously measure a single component of flow velocity by monitoring the spectral peak location. Measurements of gas temperature and density are demonstrated using a low speed heated air jet surrounded by an unheated air co-flow. Mean values of temperature and density are shown for radial scans across the jet flow at a fixed axial distance from the jet exit plane. Power spectra of temperature and density fluctuations at several locations in the jet are also shown. The instantaneous measurements have fairly high uncertainty; however, long data records provide highly accurate statistically quantities, which include power spectra. Mean temperatures are compared with thermocouple measurements as well as the temperatures derived from independent density measurements. The accuracy for mean temperature measurements was +/- 7 K.
Coherent scattering of CO2 light from ion-acoustic waves
International Nuclear Information System (INIS)
Peratt, A.L.; Watterson, R.L.; Derfler, H.
1977-01-01
Scattering of laser radiation from ion-acoustic waves in a plasma is investigated analytically and experimentally. The formulation predicts a coherent component of the scattered power on a largely incoherent background spectrum when the acoustic analog of Bragg's law and Doppler shift conditions are satisfied. The experiment consists of a hybrid CO 2 laser system capable of either low power continuous wave or high power pulsed mode operation. A heterodyne light mixing scheme is used to detect the scattered power. The proportionality predicted by the theory is verified by scattering from externally excited acoustic and ion-acoustic waves; continuous wave and pulsed modes in each case. Measurement of the ion-acoustic dispersion relation by continuous wave scattering is also presented
Passive retrieval of Rayleigh waves in disordered elastic media
International Nuclear Information System (INIS)
Larose, Eric; Derode, Arnaud; Clorennec, Dominique; Margerin, Ludovic; Campillo, Michel
2005-01-01
When averaged over sources or disorder, cross correlation of diffuse fields yields the Green's function between two passive sensors. This technique is applied to elastic ultrasonic waves in an open scattering slab mimicking seismic waves in the Earth's crust. It appears that the Rayleigh wave reconstruction depends on the scattering properties of the elastic slab. Special attention is paid to the specific role of bulk to Rayleigh wave coupling, which may result in unexpected phenomena, such as a persistent time asymmetry in the diffuse regime
International Nuclear Information System (INIS)
El-Wakil, S.A.; Sallah, M.; Degheidy, A.R.
2005-01-01
The time-dependent radiation transfer equation in plane geometry with Rayleigh scattering is studied. The traveling wave transformation is used to obtain the corresponding stationary-like equation. Pomraning-Eddington approximation is then used to calculate the radiation intensity in finite plane-parallel media. Numerical results and shielding calculations are shown for reflectivity and transmissivity at different times. The medium is assumed to have specular-reflecting boundaries. For the sake of comparison, two different weight functions are introduced and to force the boundary conditions to be fulfilled
An efficient method of randomly sampling the coherent angular scatter distribution
International Nuclear Information System (INIS)
Williamson, J.F.; Morin, R.L.
1983-01-01
Monte Carlo simulations of photon transport phenomena require random selection of an interaction process at each collision site along the photon track. Possible choices are usually limited to photoelectric absorption and incoherent scatter as approximated by the Klein-Nishina distribution. A technique is described for sampling the coherent angular scatter distribution, for the benefit of workers in medical physics. (U.K.)
Zou, Wen-Sheng; Sheng, Dong; Ge, Xin; Qiao, Jun-Qin; Lian, Hong-Zhen
2011-01-01
Rayleigh scattering (RS) as an interference factor to detection sensitivity in ordinary fluorescence spectrometry is always avoided in spite of considerable efforts toward the development of RS-based resonance Rayleigh scattering (RRS) and hyper-Rayleigh scattering (HRS) techniques. Here, combining advantages of quantum dots (QDs) including chemical modification of functional groups and the installation of recognition receptors at their surfaces with those of phosphorescence such as the avoidance of autofluorescence and scattering light, l-cys-capped Mn-doped ZnS QDs have been synthesized and used for room-temperature phosphorescence (RTP) to sense and for RS chemodosimetry to image ultratrace 2,4,6-trinitrotoluene (TNT) in water. The l-cys-capped Mn-doped ZnS QDs interdots aggregate with TNT species induced by the formation of Meisenheimer complexes (MHCs) through acid-base pairing interaction between l-cys and TNT, hydrogen bonding, and electrostatic interaction between l-cys intermolecules. Although the resultant MHCs may quench the fluorescence at 430 nm, interdots aggregation can greatly influence the light scattering property of the aqueous QDs system, and therefore, dominant RS enhancement at defect-related emission wavelength was observed under the excitation of violet light of Mn-doped ZnS QDs, which was applied in chemodosimetry to image TNT in water. Meanwhile, Mn-doped ZnS QDs also exhibited a highly selective response to the quenching of the (4)T(1)-(6)A(1) transition emission (RTP) and showed a very good linearity in the range of 0.0025-0.45 μM TNT with detection limit down to 0.8 nM and RSD of 2.3% (n = 5). The proposed methods are well-suited for detecting the ultratrace TNT and distinguishing different nitro compounds.
Neutrino coherent forward scattering and its index of refraction
International Nuclear Information System (INIS)
Liu, J.
1992-01-01
It is pointed out that, if neutrinos are to maintain coherence over the required distance for the Mikheyev-Smirnov-Wolfenstein solutions to the solar-neutrino problem, effects arising from neutrino multiple scattering must be considered. We give a simple derivation for the neutrino index of refraction that takes into account this effect. The same method is also shown to be useful for situations with varying matter densities and neutrino mixing. We also examine the question whether the coherence of propagating neutrinos in matter will be affected by switching on an external magnetic field, assuming neutrinos have a large magnetic moment
Conti, C. C.; Anjos, M. J.; Salgado, C. M.
2014-09-01
X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at www.macx.net.br.
Interference between magnetism and surface roughness in coherent soft X-ray scattering
International Nuclear Information System (INIS)
Rahmim, A.; Tixier, S.; Tiedje, T.; Eisebitt, S.; Lorgen, M.; Scherer, R.; Eberhardt, W.; Luning, J.; Scholl, A.
2002-01-01
In coherent soft x-ray scattering from magnetically ordered surfaces there are contributions to the scattering from the magnetic domains, from the surface roughness, and from the diffraction associated with the pinhole aperture used as a coherence filter. In the present work, we explore the interplay between these contributions by analyzing speckle patterns in diffusely scattered x rays from the surface of magnetic thin films. Magnetic contrast from the surface of anti ferro magnetically ordered LaFeO3 films is caused by magnetic linear dichroism in resonant x-ray scattering. The samples studied possess two types of domains with their magnetic orientations perpendicular to each other. By tuning the x-ray energy from one of the two Fe-L3 resonant absorption peaks to the other, the relative amplitudes of the x-ray scattering from the two domains is inverted which results in speckle pattern changes. A theoretical expression is derived for the intensity correlation between the speckle patterns with the magnetic contrast inverted and not inverted. The model is found to be in good agreement with the x-ray-scattering observations and independent measurements of the surface roughness. An analytical expression for the correlation function gives an explicit relation between the change in the speckle pattern and the roughness, and magnetic and aperture scattering. Changes in the speckle pattern are shown to arise from beating of magnetic scattering with the roughness scattering and diffraction from the aperture. The largest effect is found when the surface roughness scatter is comparable in intensity to the magnetic scatter
Ground, Cody R.; Gopal, Vijay; Maddalena, Luca
2018-04-01
By introducing large-scale streamwise vortices into a supersonic flow it is possible to enhance the rate of mixing between two fluid streams. However, increased vorticity content alone does not explicitly serve as a predictor of mixing enhancement. Additional factors, particularly the mutual interactions occurring between neighboring vortical structures, affect the underlying fundamental physics that influence the rate at which the fluids mix. As part of a larger systematic study on supersonic streamwise vortex interactions, this work experimentally quantifies the average rate of mixing of helium and air in the presence of two separate modes of vortex interaction, the merging and non-merging of a pair of co-rotating vortices. In these experiments vortex-generating expansion ramps are placed on a strut injector. The freestream Mach number is set at 2.5 and helium is injected as a passive scalar. Average injectant mole fractions at selected flow planes downstream of the injector are measured utilizing the filtered Rayleigh scattering technique. The filtered Rayleigh scattering measurements reveal that, in the domain surveyed, the merging vortex interaction strongly displaces the plume from its initial horizontal orientation while the non-merging vortex interaction more rapidly mixes the helium and air. The results of the current experiments are consistent with associated knowledge derived from previous analyses of the two studied configurations which have included the detailed experimental characterization of entrainment, turbulent kinetic energy, and vorticity of both modes of vortex interaction.
Dirac Coulomb Green's function and its application to relativistic Rayleigh scattering
International Nuclear Information System (INIS)
Wong, M.K.F.; Yeh, E.H.Y.
1985-01-01
The Dirac Coulomb Green's function is obtained in both coordinate and momentum space. The Green's function in coordinate space is obtained by the eigenfunction expansion method in terms of the wave functions obtained by Wong and Yeh. The result is simpler than those obtained previously by other authors, in that the radial part for each component contains one term only instead of four terms. Our Green's function reduces to the Schroedinger Green's function upon some simple conditions, chiefly by neglecting the spin and replacing lambda by l. The Green's function in momentum space is obtained as the Fourier transform of the coordinate space Green's function, and is expressed in terms of basically three types of functions: (1) F/sub A/ (α; β 1 β 2 β 3 ; γ 1 γ 2 γ 3 ; z 1 z 2 z 3 ), (2) the hypergeometric function, and (3) spherical harmonics. The matrix element for Rayleigh scattering, or elastic Compton scattering, from relativistically bound electrons is then obtained in analytically closed form. The matrix element is written basically in terms of the coordinate space Dirac Coulomb Green's function. The technique used in the evaluation of the matrix element is based on the calculation of the momentum space Dirac Coulomb Green's function. Finally the relativistic result is compared with the nonrelativistic result
Rayleigh imaging in spectral mammography
Berggren, Karl; Danielsson, Mats; Fredenberg, Erik
2016-03-01
Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton scattering. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, Rayleigh scattering may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient scatter rejection of the system enables measurement of Rayleigh scattering, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.
Coherent scattering of neutrinos by 'nuclear pasta' in dense matter
International Nuclear Information System (INIS)
Sonoda, Hidetaka
2007-01-01
We examine coherent scattering cross section of neutrino and nucleon systems via weak-neutral current at subnuclear densities, which will be important in supernova cores. Below melting density and temparature of nuclei, nuclear shape becomes rodlike and slablike; this is called nuclear 'pasta'. Transition of structure will greatly influence coherent effects which can not easily be predicted. We calculate static structure factor of nuclear matter using data of several nuclear models, and discuss the effects of existence of nuclear pasta on neutrino opacity in hot dense matter
International Nuclear Information System (INIS)
Blecker, Carlo R.; Hermann, Gerd M.
2009-01-01
Atomic absorption and coherent forward scattering spectrometry by using a near-infrared diode laser with and without Zeeman and wavelength modulation were carried out with graphite furnace electrothermal atomization. Analytical curves and limits of detection were compared. The magnetic field was modulated with 50 Hz, and the wavelength of the diode laser with 10 kHz. Coherent forward scattering was measured with crossed and slightly uncrossed polarizers. The results show that the detection limits of atomic absorption spectrometry are roughly the same as those of coherent forward scattering spectrometry with crossed polarizers. According to the theory with bright flicker noise limited laser sources the detection limits and linear ranges obtained with coherent forward scattering spectrometry with slightly uncrossed polarizers are significantly better than those obtained with crossed polarizers and with atomic absorption spectrometry. This is due to the fact that employing approaches of polarization spectroscopy reduce laser intensity fluctuations to their signal carried fractions
Energy Technology Data Exchange (ETDEWEB)
Conti, C.C., E-mail: ccconti@ird.gov.br [Institute for Radioprotection and Dosimetry – IRD/CNEN, Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Anjos, M.J. [Physics Institute, State University of Rio de Janeiro – UERJ, Rio de Janeiro (Brazil); Salgado, C.M. [Nuclear Engineering Institute – IEN/CNEN, Rio de Janeiro (Brazil)
2014-09-15
Highlights: •This work describes a procedure for sample self-absorption correction. •The use of Monte Carlo simulation to calculate the mass attenuation coefficients curve was effective. •No need for transmission measurement, saving time, financial resources and effort. •This article provides de curves for the 90° scattering angle. •Calculation on-line at (www.macx.net.br). -- Abstract: X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum, provides a link to the mass attenuation coefficient by means of a polynomial type equation. This work presents a way to construct a Rayleigh to Compton scattering ratio versus mass attenuation coefficient curve by using the MCNP5 Monte Carlo computer code. The comparison between the calculated and literature values of the mass attenuation coefficient for some known samples showed to be within 15%. This calculation procedure is available on-line at (www.macx.net.br)
Bound coherent and incoherent thermal neutron scattering cross sections of the elements
International Nuclear Information System (INIS)
Sears, V.F.
1982-12-01
An up-to-date table of bound coherent and incoherent thermal neutron scattering cross sections of the elements is presented. Values from two different data sources are calculated and compared. These sources are: (1) the free-atom cross sections listed in the Σbarn bookΣ and (2) the Julich scattering length tables. We also call attention to, and clarify, the confusion that exists in the literature concerning the sign of the imaginary part of the complex scattering length
Development of fiber lasers and devices for coherent Raman scattering microscopy
Lamb, Erin Stranford
As ultrafast laser technology has found expanding application in machining, spectroscopy, microscopy, surgery, and numerous other areas, the desire for inexpensive and robust laser sources has grown. Until recently, nonlinear effects in fiber systems due to the tight confinement of the light in the core have limited their performance. However, with advances in managing nonlinearity through pulse propagation physics and the use of large core fibers, the performance of fiber lasers can compete with that of their solid-state counterparts. As specific applications, such as coherent Raman scattering microscopy, emerge that stand to benefit from fiber technology, new performance challenges in areas such as laser noise are anticipated. This thesis studies nonlinear pulse propagation in fiber lasers and fiber parametric devices. Applications of dissipative solitons and self-similar pulse propagation to low-repetition rate oscillators that have the potential to simplify short-pulse amplification schemes will be examined. The rest of this thesis focuses on topics relevant to fiber laser development for coherent Raman scattering microscopy sources. Coherent pulse division and recombination inside the laser cavity will be introduced as an energy-scaling mechanism and demonstrated for a fiber soliton laser. The relative intensity noise properties of mode-locked fiber lasers, with a particular emphasis on normal dispersion lasers, will be explored in simulation and experiment. A fiber optical parametric oscillator will be studied in detail for low noise frequency conversion of picosecond pulses, and its utility for coherent Raman imaging will be demonstrated. Spectral compression of femtosecond pulses is used to generate picosecond pulses to pump this device, and this technique provides a route to future noise reduction in the system. Furthermore, this device forms a multimodal source capable of providing the picosecond pulses for coherent Raman scattering microscopy and the
International Nuclear Information System (INIS)
Rother, Tom
2016-01-01
In this paper I propose a classical optics experiment that results in a maximum violation of a Bell-like inequality. The first part is concerned with the Bell-like inequality (the so-called CHSH-inequality) itself. Its importance and its maximum violation in Quantum Mechanics (QM) are discussed in detail by employing an abstract probability state concept in a 4-dim. but classical event space. A T-matrix that represents the integral part of a corresponding Green's function as well as a statistical operator that contains a negative quasi-probability can be related to the corresponding quantum mechanical experiment. It is demonstrated that the derivation and usage of the T-matrix and the Green's function is equivalent to what is known from classical scattering theory. It is shown moreover that the negative quasi-probability of the statistical operator may be interpreted as a sink of probabilities related to two single events of the considered 4-dim. event space. A necessary condition for the violation of the CHSH-inequality is derived and discussed afterwards. In the second part of this paper I discuss a modification of the 4-dim. event space considered in the first part. It is shown that a combination of conventional Rayleigh scattering with a Mach–Zehnder setup would be able to put this modification into practice. Thus it becomes possible to achieve a maximum violation of the CHSH-inequality, if formulated in terms of intensities, on a pure classical way. The combination of classical light scattering with correlation experiments such as proposed in this paper may open new ways to study and to use the violation of Bell-like inequalities in modern optics. - Highlights: • Consistent Green's function formulation of the quantum mechanical Bell's experiment and its classical counterpart. This description is closely related to what is known from electromagnetic wave scattering. This is achieved by introducing an abstract probability state concept. • Discussion of a
Ultrafast spectral interferometry of resonant secondary emmission from semiconductor quantum wells
DEFF Research Database (Denmark)
Birkedal, Dan; Shah, Jagdeep
1999-01-01
Recent investigations of secondary emission from quantum well excitons follwing resonant excitation have demonstrated an intricate interplay of coherent Rayleigh scattering and incoherent luminescence. We have very recently demonstrated that it is possible to isolate and time resolve the coherent...... field associated with the Rayleigh component using ultrafast spectral interferometry, thus, obtaining substantial and new information of the nature of resonant secondary emission. Our findings demonstrate that Rayleigh scattering from static disorder is inherently a non-ergodic process invalidating...
Coherent anti-Stokes Raman scattering microscopy with a photonic crystal fiber based light source
DEFF Research Database (Denmark)
Paulsen, H.N.; Hilligsøe, Karen Marie; Thøgersen, J.
2003-01-01
A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup is demonstra......A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup...
Coherent random lasing from liquid waveguide gain channels with biological scatters
Zhang, Hong; Feng, Guoying; Wang, Shutong; Yang, Chao; Yin, Jiajia; Zhou, Shouhuan
2014-12-01
A unidirectional coherent random laser based on liquid waveguide gain channels with biological scatters is demonstrated. The optical feedback of the random laser is provided by both light scattering and waveguide confinement. This waveguide-scattering-feedback scheme not only reduces the pump threshold but also makes the output of random laser directional. The threshold of our random laser is about 11 μJ. The emission spectra can be sensitively tuned by changing pump position due to the micro/nano-scale randomness of butterfly wings. It shows the potential applications of optofluidic random lasers for bio-chemical sensors on-chip.
Quantitative use of Rayleigh waves to locate and size subsurface holes
International Nuclear Information System (INIS)
Zachary, L.W.
1982-01-01
An ultrasonic inspection method is used to obtain the circumference of a subsurface hole and the depth of the hole below the surface. A pitch-catch Rayleigh wave transducer set-up was used to launch a Rayleigh surface wave at the flaw and to capture and record the scattered waves. The frequency spectrum of the scattered waves can be used to obtain the depth of the hole. The ligament of material between the hole and the surface is sent into resonance, and this feature can be extracted from the scattered waves' frequency spectrum. The frequency is a function of the ligament length; thus the hole depth can be obtained. The circumference of the hole is found from a time of flight measurement. A Rayleigh wave is formed that travels around the hole's surface. The length of time required for the wave to travel around the hole is a measure of the circumference
Evidence of Coherent K+ Meson Production in Neutrino-Nucleus Scattering
Wang, Z.; Marshall, C. M.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Cai, T.; Carneiro, M. F.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Eberly, B.; Endress, E.; Felix, J.; Fields, L.; Fine, R.; Galindo, R.; Gallagher, H.; Ghosh, A.; Golan, T.; Gran, R.; Harris, D. A.; Higuera, A.; Hurtado, K.; Kiveni, M.; Kleykamp, J.; Kordosky, M.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Martinez Caicedo, D. A.; McFarland, K. S.; McGivern, C. L.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Norrick, A.; Nuruzzaman; Paolone, V.; Park, J.; Patrick, C. E.; Perdue, G. N.; Rakotondravohitra, L.; Ramirez, M. A.; Ransome, R. D.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Schmitz, D. W.; Simon, C.; Solano Salinas, C. J.; Tice, B. G.; Valencia, E.; Walton, T.; Wolcott, J.; Wospakrik, M.; Zavala, G.; Zhang, D.; Minerva Collaboration
2016-08-01
Neutrino-induced charged-current coherent kaon production νμA →μ-K+A is a rare, inelastic electroweak process that brings a K+ on shell and leaves the target nucleus intact in its ground state. This process is significantly lower in rate than the neutrino-induced charged-current coherent pion production because of Cabibbo suppression and a kinematic suppression due to the larger kaon mass. We search for such events in the scintillator tracker of MINERvA by observing the final state K+, μ-, and no other detector activity, and by using the kinematics of the final state particles to reconstruct the small momentum transfer to the nucleus, which is a model-independent characteristic of coherent scattering. We find the first experimental evidence for the process at 3 σ significance.
Coherent scattering and matrix correction in bone-lead measurements
International Nuclear Information System (INIS)
Todd, A.C.
2000-01-01
The technique of K-shell x-ray fluorescence of lead in bone has been used in many studies of the health effects of lead. This paper addresses one aspect of the technique, namely the coherent conversion factor (CCF) which converts between the matrix of the calibration standards and those of human bone. The CCF is conventionally considered a constant but is a function of scattering angle, energy and the elemental composition of the matrices. The aims of this study were to quantify the effect on the CCF of several assumptions which may not have been tested adequately and to compare the CCFs for plaster of Paris (the present matrix of calibration standards) and a synthetic apatite matrix. The CCF was calculated, using relativistic form factors, for published compositions of bone, both assumed and assessed compositions of plaster, and the synthetic apatite. The main findings of the study were, first, that impurities in plaster, lead in the plaster or bone matrices, coherent scatter from non-bone tissues and the individual subject's measurement geometry are all minor or negligible effects; and, second, that the synthetic apatite matrix is more representative of bone mineral than is plaster of Paris. (author)
What is measured by hyper-Rayleigh scattering from a liquid?
Rodriquez, Micheal B.; Shelton, David P.
2018-04-01
Polarization and angle dependence of hyper-Rayleigh scattering (HRS) measured for liquid acetonitrile and dimethyl sulfoxide (DMSO) is analyzed in terms of contributions from randomly oriented molecules and additional contributions produced during intermolecular collisions and induced by the electric field of dissolved ions. All three contributions show the effect of long-range correlation, and the correlation functions are determined using the HRS observations combined with the results of molecular dynamics simulations. HRS from acetonitrile is polarized transverse to the scattering vector. This is due to long-range molecular orientation correlation produced by the dipole-dipole interaction, and correlation at distances r > 100 nm must be included to account for the HRS observations. Analysis of the HRS measurements for acetonitrile determines the length scale a = 0.185 nm for the long-range longitudinal and transverse orientation correlation functions BL=-2 BT=a3/r3. Transverse polarized collision-induced HRS is also observed for acetonitrile, indicating long-range correlation of intermolecular modes. Strong longitudinal HRS is induced by the radial electric field of dissolved ions in acetonitrile. For DMSO, the angle between the molecular dipole and the vector part of the first hyperpolarizability tensor is about 100°. As a result, HRS from the randomly oriented molecules in DMSO is nearly unaffected by dipole correlation, and ion-induced HRS is weak. The strong longitudinal polarized HRS observed for DMSO is due to the collision-induced contribution, indicating long-range correlation of intermolecular modes. The HRS observations require correlation that has r-3 long-range asymptotic form, for molecular orientation and for intermolecular vibration and libration, for both acetonitrile and DMSO.
Tissue Equivalent Phantom Design for Characterization of a Coherent Scatter X-ray Imaging System
Albanese, Kathryn Elizabeth
Scatter in medical imaging is typically cast off as image-related noise that detracts from meaningful diagnosis. It is therefore typically rejected or removed from medical images. However, it has been found that every material, including cancerous tissue, has a unique X-ray coherent scatter signature that can be used to identify the material or tissue. Such scatter-based tissue-identification provides the advantage of locating and identifying particular materials over conventional anatomical imaging through X-ray radiography. A coded aperture X-ray coherent scatter spectral imaging system has been developed in our group to classify different tissue types based on their unique scatter signatures. Previous experiments using our prototype have demonstrated that the depth-resolved coherent scatter spectral imaging system (CACSSI) can discriminate healthy and cancerous tissue present in the path of a non-destructive x-ray beam. A key to the successful optimization of CACSSI as a clinical imaging method is to obtain anatomically accurate phantoms of the human body. This thesis describes the development and fabrication of 3D printed anatomical scatter phantoms of the breast and lung. The purpose of this work is to accurately model different breast geometries using a tissue equivalent phantom, and to classify these tissues in a coherent x-ray scatter imaging system. Tissue-equivalent anatomical phantoms were designed to assess the capability of the CACSSI system to classify different types of breast tissue (adipose, fibroglandular, malignant). These phantoms were 3D printed based on DICOM data obtained from CT scans of prone breasts. The phantoms were tested through comparison of measured scatter signatures with those of adipose and fibroglandular tissue from literature. Tumors in the phantom were modeled using a variety of biological tissue including actual surgically excised benign and malignant tissue specimens. Lung based phantoms have also been printed for future
Theoretical study of the slow neutron coherent scattering by nemanic liquid crystals
International Nuclear Information System (INIS)
Sugakov, V.I.; Shiyanovskij, S.V.
1982-01-01
An exact expression is obtained for neutron coherent quasielastic scattering cross section in nematic liquid crystals. Expressions are analyzed or big and small values of scattering wave vector. In the first case scattering is occured on the separate molecules and the account of the molecule form noncylindricity is to be essential. In the second case an intermolecular correlations contribute greatly to cross sections. A connection is found for pair correlation function with fluctuation for density, dipole moment and order parameters. The performed cross section analysis allow to determine the significant microscopic parameters of the nematic liquid crystal from the experimental data of slow neutron scattering
Rayleigh scattering of Moessbauer radiation in superionic conductor RbAg/sub 4/I/sub 5/
Energy Technology Data Exchange (ETDEWEB)
Ovanesyan, N.S.; Goffman, V.G.; Sokolov, V.B.; Tkachev, V.V. (AN SSSR, Chernogolovka. Otdelenie Inst. Khimicheskoj Fiziki)
1984-04-01
The dynamical properties of RbAg/sub 4/I/sub 5/ has been investiaated by Rayleigh scattering of Moessbauer radiation (RSMR) with wave-length lambda = 0.86 A. The character of Ag/sup +/ ion oscillatory motion and diffusion in RbAg/sub 4/I/sub 5/ depending on temperature including the phase transitions region is studied. It is shown that in the superionic crystal RbAg/sub 4/I/sub 5/ the diffusion process is strongly correlated, i.e. a great number of initial and final states at diffusion jumps coincide. The observed broadening can be less than the expected one by value orders. Diffusion correlation can strongly reduce the activation barrier and lead to anomalously high ionic conduction.
Coherent photon scattering cross sections for helium near the delta resonance
International Nuclear Information System (INIS)
Delli Carpini, D.; Booth, E.C.; Miller, J.P.; Igarashi, R.; Bergstrom, J.; Caplan, H.; Doss, M.; Hallin, E.; Rangacharyulu, C.; Skopik, D.; Lucas, M.A.; Nathan, A.M.; Wells, D.P.
1991-01-01
The angular distributions for coherent photon scattering from 4 He were measured at average laboratory bremsstrahlung energies of 187, 235, and 280 MeV. The experiment was performed at the Saskatchewan Accelerator Laboratory using the new high duty factor electron beam. The scattered photons were observed with a high-resolution NaI(Tl) total absorption scintillation detector. These measurements are intended to investigate modification of the Δ properties inside the nuclear medium and the treatment of nonresonant contributions to the scattering cross sections. The results are compared to theoretical calculations in the isobar-hole model. Clear deviations from the theory are evident at all energies, especially at 187 MeV
Coherent and Incoherent Neutral Current Scattering for Supernova Detection
Directory of Open Access Journals (Sweden)
P. C. Divari
2012-01-01
Full Text Available The total cross sections as well as the neutrino event rates are calculated in the neutral current neutrino scattering off 40Ar and 132Xe isotopes at neutrino energies (Ev<100 MeV. The individual contribution coming from coherent and incoherent channels is taking into account. An enhancement of the neutral current component is achieved via the coherent (0gs+→0gs+ channel which is dominant with respect to incoherent (0gs+→Jf one. The response of the above isotopes as a supernova neutrino detection has been considered, assuming a two parameter Fermi-Dirac distribution for the supernova neutrino energy spectra. The calculated total cross sections are tested on a gaseous spherical TPC detector dedicated for supernova neutrino detection.
International Nuclear Information System (INIS)
Bohidar, H.; Berland, T.; Boger, F.; Joessang, T.; Feder, J.
1987-01-01
The development of a Multipass Fabry-Perot interforometer assembly for use in Rayleigh-Brillouin scattering experiments is reported. The optical alignment and the scattered signal data acquisition have been completely computerized. Digital scanning and alignment strategies of the Fabry-Perot resonator have been incorporated, which makes this instrument quite unique in this respect. The high contrast (∼10 10 ) and finesse (∼50) offered by this instrument makes it possible to detect Brillouin peaks from samples that have a small Brillouin scattering cross-section. As part of this system a compatible and precision sample chamber has been constructed, which has been designed to operate in the pressure and temperature ranges of 1-1000B and 20-150 o C, respectively. The cell has been constructed to be small and compact, but it still has a large heat capacity (∼250J/K) which ensures easy and stable temperature control of the liquid sample volume which has a size of 40 mm 3 . The achievable temperature stability is +-1mK and +-2mK for operating temperatures below and above 100 o C, respectively. The pressure stability is in the range of +-0.05B of the set pressure for pressures below 100B and it is +-0.05% for higher pressures up to 1000B. Both pressure and temperature are remotely monitored and controlled by a ND/100 computer. Special care has been taken in designing the optics of the pressure cell to ensure that both the primary and secondary reflections from the entrance window, as well as the main beam, go out of the scattering region in order to achieve higher signal-to-noise ratio in actual experiments
Directory of Open Access Journals (Sweden)
Xi Shao
2016-03-01
Full Text Available The Visible Infrared Imaging Radiometer Suite (VIIRS onboard Suomi National Polar Orbiting Partnership (SNPP uses a solar diffuser (SD as its radiometric calibrator for the reflective solar band calibration. The SD is made of Spectralon™ (one type of fluoropolymer and was chosen because of its controlled reflectance in the Visible/Near-Infrared/Shortwave-Infrared region and its near-Lambertian reflectance property. On-orbit changes in VIIRS SD reflectance as monitored by the Solar Diffuser Stability Monitor showed faster degradation of SD reflectance for 0.4 to 0.6 µm channels than the longer wavelength channels. Analysis of VIIRS SD reflectance data show that the spectral dependent degradation of SD reflectance in short wavelength can be explained with a SD Surface Roughness (length scale << wavelength based Rayleigh Scattering (SRRS model due to exposure to solar UV radiation and energetic particles. The characteristic length parameter of the SD surface roughness is derived from the long term reflectance data of the VIIRS SD and it changes at approximately the tens of nanometers level over the operational period of VIIRS. This estimated roughness length scale is consistent with the experimental result from radiation exposure of a fluoropolymer sample and validates the applicability of the Rayleigh scattering-based model. The model is also applicable to explaining the spectral dependent degradation of the SDs on other satellites. This novel approach allows us to better understand the physical processes of the SD degradation, and is complementary to previous mathematics based models.
Scattering by a plane-parallel layer with high concentration of optically soft particles
International Nuclear Information System (INIS)
Loiko, Valery A.; Berdnik, Vladimir V.
2009-01-01
A method describing light propagation in a plane-parallel light-scattering layer with large concentration of homogeneous particles is developed. It is based on the radiative transfer equation and the doubling method. The interference approximation is used to take into account collective scattering effects. Spectral dependence of transmitted light for a layer of nonabsorbing optically soft particles with subwavelength-sized particles is investigated. At small volume concentration of the particles the weak spectral dependences of wave exponents for coherently transmitted and diffuse light are observed. It is shown that in a layer with large volume concentration of the subwavelength-sized particles the wave exponent can exceed considerably the value of four, which takes place for the Rayleigh particles. The dependence of wave exponents for coherently transmitted and diffuse light on the refractive index and concentration of particles is investigated in detail. Multiple scattering of light results in the reduction of the exponent. The quantitative results are presented and discussed. It is shown that there is a range of wavelengths where the negative values of the wave exponent at the regime of multiple scattering are implemented.
Hu, Yingtian; Liu, Chao; Wang, Xiaoping; Zhao, Dongdong
2018-06-01
At present the general scatter handling methods are unsatisfactory when scatter and fluorescence seriously overlap in excitation emission matrix. In this study, an adaptive method for scatter handling of fluorescence data is proposed. Firstly, the Raman scatter was corrected by subtracting the baseline of deionized water which was collected in each experiment to adapt to the intensity fluctuations. Then, the degrees of spectral overlap between Rayleigh scatter and fluorescence were classified into three categories based on the distance between the spectral peaks. The corresponding algorithms, including setting to zero, fitting on single or both sides, were implemented after the evaluation of the degree of overlap for individual emission spectra. The proposed method minimized the number of fitting and interpolation processes, which reduced complexity, saved time, avoided overfitting, and most importantly assured the authenticity of data. Furthermore, the effectiveness of this procedure on the subsequent PARAFAC analysis was assessed and compared to Delaunay interpolation by conducting experiments with four typical organic chemicals and real water samples. Using this method, we conducted long-term monitoring of tap water and river water near a dyeing and printing plant. This method can be used for improving adaptability and accuracy in the scatter handling of fluorescence data.
El-Kader, M. S. A.; Godet, J.-L.; Gustafsson, M.; Maroulis, G.
2018-04-01
Quantum mechanical lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) at room temperature (295 K) are computed for gaseous mixtures of molecular hydrogen with neon, krypton and xenon. The induced spectra are detected using theoretical values for induced dipole moment, pair-polarizability trace and anisotropy, hyper-polarizability and updated intermolecular potentials. Good agreement is observed for all spectra when the literature and the present potentials which are constructed from the transport and thermo-physical properties are used.
Gordon, Howard R.; Wang, Menghua
1992-01-01
The first step in the Coastal Zone Color Scanner (CZCS) atmospheric-correction algorithm is the computation of the Rayleigh-scattering (RS) contribution, L sub r, to the radiance leaving the top of the atmosphere over the ocean. In the present algorithm, L sub r is computed by assuming that the ocean surface is flat. Calculations of the radiance leaving an RS atmosphere overlying a rough Fresnel-reflecting ocean are presented to evaluate the radiance error caused by the flat-ocean assumption. Simulations are carried out to evaluate the error incurred when the CZCS-type algorithm is applied to a realistic ocean in which the surface is roughened by the wind. In situations where there is no direct sun glitter, it is concluded that the error induced by ignoring the Rayleigh-aerosol interaction is usually larger than that caused by ignoring the surface roughness. This suggests that, in refining algorithms for future sensors, more effort should be focused on dealing with the Rayleigh-aerosol interaction than on the roughness of the sea surface.
Tian, Fengling; Huang, Wei; Yang, Jidong; Li, Qin
In pH 3.25-3.35 Britton-Robinson (BR) buffer solution, albendazole (ABZ) could react with eosin Y (EY) to form a 1:1 ion-association complex, which not only results in the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS) and frequency doubling scattering (FDS). Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 356 nm. The detection limit for ABZ were 21.51 ng mL-1 for the fluorophotometry, 6.93 ng mL-1 for the RRS method and 12.89 ng mL-1 for the FDS method. Among them, the RRS method had the highest sensitivity. The experimental conditions were optimized and effects of coexisting substances were evaluated. Meanwhile, the influences of coexisting substances were tested. The methods have been successfully applied to the determination of ABZ in capsules and human urine samples. The composition and structure of the ion-association complex and the reaction mechanism were discussed.
Thakkar, Disha; Gevriya, Bhavesh; Mashru, R. C.
2014-03-01
Linezolid reacted with palladium to form 1:1 binary cationic chelate which further reacted with eosin dye to form 1:1 ternary ion association complex at pH 4 of Walpole's acetate buffer in the presence of methyl cellulose. As a result not only absorption spectra were changed but Resonance Rayleigh Scattering (RRS), Second-order Scattering (SOS) and Frequency Doubling Scattering (FDS) intensities were greatly enhanced. The analytical wavelengths of RRS, SOS and FDS (λex/λem) of ternary complex were located at 538 nm/538 nm, 240 nm/480 nm and 660 nm/330 nm, respectively. The linearity range for RRS, SOS and FDS methods were 0.01-0.5 μg mL-1, 0.1-2 μg mL-1 and 0.2-1.8 μg mL-1, respectively. The sensitivity order of three methods was as RRS > SOS > FDS. Accuracy of all methods were determined by recovery studies and showed recovery between 98% and 102%. Intraday and inter day precision were checked for all methods and %RSD was found to be less than 2 for all methods. The effects of foreign substances were tested on RRS method and it showed the method had good selectivity. For optimization of process parameter, Taguchi orthogonal array design L8(24) was used and ANOVA was adopted to determine the statistically significant control factors that affect the scattering intensities of methods. The reaction mechanism, composition of ternary ion association complex and reasons for scattering intensity enhancement was discussed in this work.
Petoukhova, A. L.; Steenbergen, W.; van Leeuwen, T. G.; de Mul, F. F. M.
2002-01-01
A low coherence Mach-Zehnder interferometer is developed for path length resolved dynamic light scattering in highly turbid media. The path length distribution of multiply scattered photons in Intralipid is changed by the addition of absorbing dyes. Path length distributions obtained for various
DEFF Research Database (Denmark)
Andresen, Esben Ravn; Paulsen, Henrik Nørgaard; Birkedal, Victoria
2006-01-01
We demonstrate spectral multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy and microscopy based on a single Ti:sapphire oscillator and a nonlinear photonic-crystal fiber (PCF). The Stokes pulse is generated by spectral conversion of the laser pulse in a PCF. The pump pulse is eit...
Third-harmonic generation and scattering in combustion flames using a femtosecond laser filament.
Zang, Hong-Wei; Li, He-Long; Su, Yue; Fu, Yao; Hou, Meng-Yao; Baltuška, Andrius; Yamanouchi, Kaoru; Xu, Huailiang
2018-02-01
Coherent radiation in the ultraviolent (UV) range has high potential applicability to the diagnosis of the formation processes of soot in combustion because of the high scattering efficiency in the UV wavelength region, even though the UV light is lost largely by the absorption within the combustion flames. We show that the third harmonic (TH) of a Ti:sapphire 800 nm femtosecond laser is generated in a laser-induced filament in a combustion flame and that the conversion efficiency of the TH varies sensitively by the ellipticity of the driver laser pulse but does not vary so much by the choice of alkanol species introduced as fuel for the combustion flames. We also find that the TH recorded from the side direction of the filament is the Rayleigh scattering of the TH by soot nanoparticles within the flame and that the intensity of the TH varies depending on the fuel species as well as on the position of the laser filament within the flame. Our results show that a remote and in situ measurement of distributions of soot nanoparticles in a combustion flame can be achieved by Rayleigh scattering spectroscopy of the TH generated by a femtosecond-laser-induced filament in the combustion flame.
First measurement of the Rayleigh cross section
Naus, H.; Ubachs, W.
2000-01-01
Rayleigh cross section for N2, Ar and SF6 was performed using the technique of cavity ring-down spectroscopy (CRDS). The experiment was based on the assumption that scattering cross section is equal to the extinction in the absence of absorption. The theory explains the molecular origin of
A method of atmospheric density measurements during Shuttle entry using UV laser Rayleigh scattering
Mckenzie, Robert L.
1987-01-01
A detailed study is described of the performance capabilities and the hardware requirements for a method in which ambient density is measured along the Space Shuttle flight path using on-board optical instrumentation. The technique relies on Rayleigh scattering of light from a pulsed, ultraviolet, ArF excimer laser operating at a wavelength of 193 nm. The method is shown to be capable of providing direct measurements of ambient density with an uncertainty of less than 1 percent and with a spatial resolution of 1 km, over an altitude range from 50 to 90 km. In addition, extensions of this concept are discussed that allow measurements of the shock wave location and the density profile within the shock layer. Two approaches are identified that appear to be feasible, in which the same laser system is used for the extended measurements as that required for the ambient density measurements.
International Nuclear Information System (INIS)
Batchelar, Deidre L.; Davidson, Melanie T.M.; Dabrowski, Waldemar; Cunningham, Ian A.
2006-01-01
Quantitative analysis of bone composition is necessary for the accurate diagnosis and monitoring of metabolic bone diseases. Accurate assessment of the bone mineralization state is the first requirement for a comprehensive analysis. In diagnostic imaging, x-ray coherent scatter depends upon the molecular structure of tissues. Coherent-scatter computed tomography (CSCT) exploits this feature to identify tissue types in composite biological specimens. We have used CSCT to map the distributions of tissues relevant to bone disease (fat, soft tissue, collagen, and mineral) within bone-tissue phantoms and an excised cadaveric bone sample. Using a purpose-built scanner, we have measured hydroxyapatite (bone mineral) concentrations based on coherent-scatter patterns from a series of samples with varying hydroxyapatite content. The measured scatter intensity is proportional to mineral density in true g/cm 3 . Repeated measurements of the hydroxyapatite concentration in each sample were within, at most, 2% of each other, revealing an excellent precision in determining hydroxyapatite concentration. All measurements were also found to be accurate to within 3% of the known values. Phantoms simulating normal, over-, and under-mineralized bone were created by mixing known masses of pure collagen and hydroxyapatite. An analysis of the composite scatter patterns gave the density of each material. For each composite, the densities were within 2% of the known values. Collagen and hydroxyapatite concentrations were also examined in a bone-mimicking phantom, incorporating other bone constituents (fat, soft tissue). Tomographic maps of the coherent-scatter properties of each specimen were reconstructed, from which material-specific images were generated. Each tissue was clearly distinguished and the collagen-mineral ratio determined from this phantom was also within 2% of the known value. Existing bone analysis techniques cannot determine the collagen-mineral ratio in intact specimens
International Nuclear Information System (INIS)
Adam, B; Celeste, W; Christian, H; Wolfgang, S; Norman, M
2007-01-01
This feasibility study sought to demonstrate several necessary steps in a research program whose ultimate goal is to detect coherent scattering of reactor antineutrinos in dual-phase noble liquid detectors. By constructing and operating a Argon gas-phase drift and scintillation test-bed, the study confirmed important expectations about sensitivity of these detectors, and thereby met the goals set forth in our original proposal. This work has resulted in a successful Lab-Wide LDRD for design and deployment of a coherent scatter detector at a nuclear reactor, and strong interest by DOE Office of Science. In recent years, researchers at LLNL and elsewhere have converged on a design approach for a new generation of very low noise, low background particle detectors known as two-phase noble liquid/noble gas ionization detectors. This versatile class of detector can be used to detect coherent neutrino scattering-an as yet unmeasured prediction of the Standard Model of particle physics. Using the dual phase technology, our group would be the first to verify the existence of this process. Its (non)detection would (refute)validate central tenets of the Standard Model. The existence of this process is also important in astrophysics, where coherent neutrino scattering is assumed to play an important role in energy transport within nascent neutron stars. The potential scientific impact after discovery of coherent neutrino-nuclear scattering is large. This phenomenon is flavor-blind (equal cross-sections of interaction for all three neutrino types), raising the possibility that coherent scatter detectors could be used as total flux monitors in future neutrino oscillation experiments. Such a detector could also be used to measure the flavor-blind neutrino spectrum from the next nearby (d ∼ 10kpc) type Ia supernova explosion. The predicted number of events [integrated over explosion time] for a proposed dual-phase argon coherent neutrino scattering detector is 10000 nuclear
International Nuclear Information System (INIS)
Volkmer, Andreas; Cheng, Ji-Xin; Sunney Xie, X.
2001-01-01
We demonstrate theoretically and experimentally a novel epidetection scheme for coherent anti-Stokes Raman scattering (CARS) microscopy that significantly improves the detection sensitivity. Calculations show that epidetected CARS (E-CARS) signals are present for scatterers smaller than the wavelength of light, whereas the large background signals from the surrounding bulk solvent are suppressed by destructive interference. E-CARS microscopy is capable of revealing small intracellular features that are otherwise buried by the strong water CARS signal
QCD coherence in deep inelastic scattering at small x at HERA
International Nuclear Information System (INIS)
Golec-Biernat, K.
1998-01-01
QCD coherence effects in initial state radiation at small x in deep inelastic scattering in HERA kinematics are studied with the help of the Monte Carlo model SMALLX. Theoretical assumptions based on the CCFM evolution equation are reviewed and the basic properties of the partonic final states are investigated. The results are compared with those obtained in the conventional DGLAP evolution scheme. (orig.)
Krywonos, Andrey; Harvey, James E; Choi, Narak
2011-06-01
Scattering effects from microtopographic surface roughness are merely nonparaxial diffraction phenomena resulting from random phase variations in the reflected or transmitted wavefront. Rayleigh-Rice, Beckmann-Kirchhoff. or Harvey-Shack surface scatter theories are commonly used to predict surface scatter effects. Smooth-surface and/or paraxial approximations have severely limited the range of applicability of each of the above theoretical treatments. A recent linear systems formulation of nonparaxial scalar diffraction theory applied to surface scatter phenomena resulted first in an empirically modified Beckmann-Kirchhoff surface scatter model, then a generalized Harvey-Shack theory that produces accurate results for rougher surfaces than the Rayleigh-Rice theory and for larger incident and scattered angles than the classical Beckmann-Kirchhoff and the original Harvey-Shack theories. These new developments simplify the analysis and understanding of nonintuitive scattering behavior from rough surfaces illuminated at arbitrary incident angles.
Background studies for the MINER Coherent Neutrino Scattering reactor experiment
International Nuclear Information System (INIS)
Agnolet, G.; Baker, W.; Barker, D.; Beck, R.; Carroll, T.J.; Cesar, J.; Cushman, P.; Dent, J.B.; De Rijck, S.; Dutta, B.; Flanagan, W.; Fritts, M.; Gao, Y.; Harris, H.R.; Hays, C.C.; Iyer, V.
2017-01-01
The proposed Mitchell Institute Neutrino Experiment at Reactor (MINER) experiment at the Nuclear Science Center at Texas A&M University will search for coherent elastic neutrino-nucleus scattering within close proximity (about 2 m) of a 1 MW TRIGA nuclear reactor core using low threshold, cryogenic germanium and silicon detectors. Given the Standard Model cross section of the scattering process and the proposed experimental proximity to the reactor, as many as 5–20 events/kg/day are expected. We discuss the status of preliminary measurements to characterize the main backgrounds for the proposed experiment. Both in situ measurements at the experimental site and simulations using the MCNP and GEANT4 codes are described. A strategy for monitoring backgrounds during data taking is briefly discussed.
Coherent anti-Stokes Raman scattering microscopy (CARS): Instrumentation and applications
International Nuclear Information System (INIS)
Djaker, Nadia; Lenne, Pierre-Francois; Marguet, Didier; Colonna, Anne; Hadjur, Christophe; Rigneault, Herve
2007-01-01
Recent advances in laser physics have permitted the development of a new kind of microscopy based on stimulated Raman scattering. This new technique known as Coherent anti-Stokes Raman scattering (CARS) microscopy allows vibrational imaging with high sensitivity, high spectral resolution and three-dimensional sectioning capabilities. We review recent advances in CARS microscopy, with applications to chemical and biological systems. We also present an application of CARS microscopy with high optical resolution and spectral selectivity, in resolving structures in surface ex vivo stratum corneum by looking at the CH 2 stretching vibrational band. A strong CARS signal is backscattered from an intense forward generated CARS signal in thick samples. This makes noninvasive imaging of deep structures possible, without labeling or chemical treatments
Background studies for the MINER Coherent Neutrino Scattering reactor experiment
Energy Technology Data Exchange (ETDEWEB)
Agnolet, G.; Baker, W. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Barker, D. [School of Physics & Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Beck, R. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Carroll, T.J.; Cesar, J. [Department of Physics, University of Texas at Austin, Austin, TX 78712 (United States); Cushman, P. [School of Physics & Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Dent, J.B. [Department of Physics, University of Louisiana at Lafayette, Lafayette, LA 70504 (United States); De Rijck, S. [Department of Physics, University of Texas at Austin, Austin, TX 78712 (United States); Dutta, B. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Flanagan, W. [Department of Physics, University of Texas at Austin, Austin, TX 78712 (United States); Fritts, M. [School of Physics & Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Gao, Y. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Department of Physics & Astronomy, Wayne State University, Detroit 48201 (United States); Harris, H.R.; Hays, C.C. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Iyer, V. [School of Physical Sciences, National Institute of Science Education and Research, Jatni - 752050 (India); and others
2017-05-01
The proposed Mitchell Institute Neutrino Experiment at Reactor (MINER) experiment at the Nuclear Science Center at Texas A&M University will search for coherent elastic neutrino-nucleus scattering within close proximity (about 2 m) of a 1 MW TRIGA nuclear reactor core using low threshold, cryogenic germanium and silicon detectors. Given the Standard Model cross section of the scattering process and the proposed experimental proximity to the reactor, as many as 5–20 events/kg/day are expected. We discuss the status of preliminary measurements to characterize the main backgrounds for the proposed experiment. Both in situ measurements at the experimental site and simulations using the MCNP and GEANT4 codes are described. A strategy for monitoring backgrounds during data taking is briefly discussed.
Yan, Aidong; Huang, Sheng; Li, Shuo; Chen, Rongzhang; Ohodnicki, Paul; Buric, Michael; Lee, Shiwoo; Li, Ming-Jun; Chen, Kevin P
2017-08-24
This paper reports a technique to enhance the magnitude and high-temperature stability of Rayleigh back-scattering signals in silica fibers for distributed sensing applications. With femtosecond laser radiation, more than 40-dB enhancement of Rayleigh backscattering signal was generated in silica fibers using 300-nJ laser pulses at 250 kHz repetition rate. The laser-induced Rayleigh scattering defects were found to be stable from the room temperature to 800 °C in hydrogen gas. The Rayleigh scatter at high temperatures was correlated to the formation and modification of nanogratings in the fiber core. Using optical fibers with enhanced Rayleigh backscattering profiles as distributed temperature sensors, we demonstrated real-time monitoring of solid oxide fuel cell (SOFC) operations with 5-mm spatial resolution at 800 °C. Information gathered by these fiber sensor tools can be used to verify simulation results or operated in a process-control system to improve the operational efficiency and longevity of SOFC-based energy generation systems.
DEFF Research Database (Denmark)
Pedersen, Pernille Klarskov; Isomäki, Antti; Hansen, Kim P.
2011-01-01
Photonic crystal fiber (PCF) designs with two zero-dispersion wavelengths (ZDWs) are experimentally investigated in order to suggest a novel PCF for coherent anti-Stokes Raman scattering (CARS) microscopy. From our investigation, we select the optimum PCF design and demonstrate a tailored spectru...
Study of Rayleigh-Love coupling from Spatial Gradient Observation
Lin, C. J.; Hosseini, K.; Donner, S.; Vernon, F.; Wassermann, J. M.; Igel, H.
2017-12-01
We present a new method to study Rayleigh-Love coupling. Instead of using seismograms solely, where ground motion is recorded as function of time, we incorporate with rotation and strain, also called spatial gradient where ground is represented as function of distance. Seismic rotation and strain are intrinsic different observable wavefield so are helpful to indentify wave type and wave propagation. A Mw 7.5 earthquake on 29 March 2015 occurred in Kokopo, Papua New Guinea recorded by a dense seismic array at PFO, California are used to obtaint seismic spatial gradient. We firstly estimate time series of azimuthal direction and phase velocity of SH wave and Rayleigh wave by analyzing collocated seismograms and rotations. This result also compares with frequency wavenumber methods using a nearby ANZA seismic array. We find the direction of Rayleigh wave fits well with great-circle back azimuth during wave propagation, while the direction of Love wave deviates from that, especially when main energy of Rayleigh wave arrives. From the analysis of cross-correlation between areal strain and vertical rotation, it reveals that high coherence, either positive or negative, happens at the same time when Love wave deparate from great-circle path. We also find the observed azimuth of Love wave and polarized particle motion of Rayleigh wave fits well with the fast direction of Rayleigh wave, for the period of 50 secs. We conclude the cause of deviated azimuth of Love wave is due to Rayleigh-Love coupling, as surface wave propagates through the area with anisotropic structure.
Energy Technology Data Exchange (ETDEWEB)
Guetlein, Achim; Ciemniak, Christian; Feilitzsch, Franz von; Lanfranchi, Jean-Come; Oberauer, Lothar; Potzel, Walter; Roth, Sabine; Schoenert, Stefan; Sivers, Moritz von; Strauss, Raimund; Wawoczny, Stefan; Willers, Michael; Zoeller, Andreas [Technische Universitaet Muenchen, Physik-Department, E15 (Germany)
2012-07-01
The Coherent Neutrino Nucleus Scattering (CNNS) is a neutral current process of the weak interaction and is thus flavor independent. A low-energetic neutrino scatters off a target nucleus. For low transferred momenta the wavelength of the transferred Z{sup 0} boson is comparable to the diameter of the target nucleus. Thus, the neutrino interacts with all nucleons coherently and the cross section for the CNNS is enhanced. To observe CNNS for the first time we are developing cryogenic detectors with a target mass of about 10 g each and an energy threshold of less than 0.5 keV. The current status of this development is presented as well as the estimated background for an experiment in the vicinity of a nuclear power reactor as a strong neutrino source.
Coherent scattering of three-level atoms in the field of a bichromatic standing light wave
International Nuclear Information System (INIS)
Pazgalev, A.S.; Rozhdestvenskii, Yu.V.
1996-01-01
We discuss the coherent scattering of three-level atoms in the field of two standing light waves for two values of the spatial shift. In the case of a zero spatial shift and equal frequency detunings of the standing waves, the problem of scattering of a three-level atoms is reduced to scattering of an effectively two-level atom. For the case of an exact resonance between the waves and transitions we give expressions for the population probability of the states of the three-level atom obtained in the short-interaction-time approximation. Depending on the initial population distribution over the states, different scattering modes are realized. In particular, we show that there can be initial conditions for which the three-level system does not interact with the field of the standing waves, with the result that there is no coherent scattering of atoms. In the case of standing waves shifted by π/2, there are two types of solution, depending on the values of the frequency detuning. For instance, when the light waves are detuned equally we give the exact solution for arbitrary relationships between the detuning and the standing wave intensities valid for any atom-field interaction times. The case of 'mirror' detunings and shifted standing waves is studied only numerically
Concentric layered Hermite scatterers
Astheimer, Jeffrey P.; Parker, Kevin J.
2018-05-01
The long wavelength limit of scattering from spheres has a rich history in optics, electromagnetics, and acoustics. Recently it was shown that a common integral kernel pertains to formulations of weak spherical scatterers in both acoustics and electromagnetic regimes. Furthermore, the relationship between backscattered amplitude and wavenumber k was shown to follow power laws higher than the Rayleigh scattering k2 power law, when the inhomogeneity had a material composition that conformed to a Gaussian weighted Hermite polynomial. Although this class of scatterers, called Hermite scatterers, are plausible, it may be simpler to manufacture scatterers with a core surrounded by one or more layers. In this case the inhomogeneous material property conforms to a piecewise continuous constant function. We demonstrate that the necessary and sufficient conditions for supra-Rayleigh scattering power laws in this case can be stated simply by considering moments of the inhomogeneous function and its spatial transform. This development opens an additional path for construction of, and use of scatterers with unique power law behavior.
LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES
International Nuclear Information System (INIS)
Zugger, M. E.; Kane, T. J.; Kasting, J. F.; Williams, D. M.; Philbrick, C. R.
2010-01-01
Orbital variation in reflected starlight from exoplanets could eventually be used to detect surface oceans. Exoplanets with rough surfaces, or dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude (OL) = 180 0 , whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30 0 . Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74 0 ; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach peak polarization near OL = 90 0 , but clouds and Lambertian surface scattering dilute and shift this peak to smaller OL. A shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. Our calculations suggest that polarization alone may not positively identify the presence of an ocean under an Earth-like atmosphere; however, polarization adds another dimension which can be used, in combination with unpolarized orbital light curves and contrast ratios, to detect extrasolar oceans, atmospheric water aerosols, and water clouds. Additionally, the presence and direction of the polarization vector could be used to determine planet association with the star, and constrain orbit inclination.
Diode Laser Velocity Measurements by Modulated Filtered Rayleigh Scattering
Mach, J. J.; Varghese, P. L.; Jagodzinski, J. J.
1999-01-01
The ability of solid-state lasers to be tuned in operating frequency at MHz rates by input current modulation, while maintaining a relatively narrow line-width, has made them useful for spectroscopic measurements. Their other advantages include low cost, reliability, durability, compact size, and modest power requirements, making them a good choice for a laser source in micro-gravity experiments in drop-towers and in flight. For their size, they are also very bright. In a filtered Rayleigh scattering (FRS) experiment, a diode laser can be used to scan across an atomic or molecular absorption line, generating large changes in transmission at the resonances for very small changes in frequency. The hyperfine structure components of atomic lines of alkali metal vapors are closely spaced and very strong, which makes such atomic filters excellent candidates for sensitive Doppler shift detection and therefore for high-resolution velocimetry. In the work we describe here we use a Rubidium vapor filter, and work with the strong D(sub 2) transitions at 780 nm that are conveniently accessed by near infrared diode lasers. The low power output of infrared laser diodes is their primary drawback relative to other laser systems commonly used for velocimetry. However, the capability to modulate the laser frequency rapidly and continuously helps mitigate this. Using modulation spectroscopy and a heterodyne detection scheme with a lock-in amplifier, one can extract sub-microvolt signals occurring at a specific frequency from a background that is orders of magnitude stronger. The diode laser modulation is simply achieved by adding a small current modulation to the laser bias current. It may also be swept repetitively in wavelength using an additional lower frequency current ramp.
Atomic form factors, incoherent scattering functions, and photon scattering cross sections
International Nuclear Information System (INIS)
Hubbell, J.H.; Veigele, W.J.; Briggs, E.A.; Brown, R.T.; Cromer, D.T.; Howerton, R.J.
1975-01-01
Tabulations are presented of the atomic form factor, F (α,Z), and the incoherent scattering function, S (x,Z), for values of x (=sin theta/2)/lambda) from 0.005 A -1 to 10 9 A -1 , for all elements A=1 to 100. These tables are constructed from available state-of-the-art theoretical data, including the Pirenne formulas for Z=1, configuration-into action results by Brown using Brown-Fontana and Weiss correlated wavefunctions for Z=2 to 6 non-relativistic Hartree-Fock results by Cromer for Z=7 to 100 and a relativistic K-shell analytic expression for F (x,Z) by Bethe Levinger for x>10 A -1 for all elements Z=2 to 100. These tabulated values are graphically compared with available photon scattering angular distribution measurements. Tables of coherent (Rayleigh) and incoherent (Compton) total scattering cross sections obtained by nummerical integration over combinations of F 2 (x,Z) with the Thomson formula and S (x,Z) with the Klum-Nishina Formual, respectively, are presented for all elements Z=1 to 100, for photon energies 100 eV (lambda=124 A) to 100 MeV (0.000124 A). The incoherent scattering cross sections also include the radiative and double-Compton corrections as given by Mork. Similar tables are presented for the special cases of terminally-bonded hydrogen and for the H 2 molecule, interpolated and extrapolated from values calculated by Stewart et al., and by Bentley and Stewart using Kolos-Roothaan wavefunctions
Gachet, David; Rigneault, Hervé
2011-12-01
We develop a full vectorial theoretical investigation of the chemical interface detection in conventional coherent anti-Stokes Raman scattering (CARS) microscopy. In Part I, we focus on the detection of axial interfaces (i.e., parallel to the optical axis) following a recent experimental demonstration of the concept [Phys. Rev. Lett. 104, 213905 (2010)]. By revisiting the Young's double slit experiment, we show that background-free microscopy and spectroscopy is achievable through the angular analysis of the CARS far-field radiation pattern. This differential CARS in k space (Dk-CARS) technique is interesting for fast detection of interfaces between molecularly different media. It may be adapted to other coherent and resonant scattering processes.
Energy Technology Data Exchange (ETDEWEB)
Motozawa, Masaaki, E-mail: motozawa.masaaki@shizuoka.ac.jp [Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu-shi, Shizuoka 432-8561 (Japan); Muraoka, Takashi [Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu-shi, Shizuoka 432-8561 (Japan); Motosuke, Masahiro, E-mail: mot@rs.tus.ac.jp [Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585 (Japan); Fukuta, Mitsuhiro, E-mail: fukuta.mitsuhiro@shizuoka.ac.jp [Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu-shi, Shizuoka 432-8561 (Japan)
2017-04-15
It can be expected that the thermal diffusivity of a magnetic fluid varies from time to time after applying a magnetic field because of the growth of the inner structure of a magnetic fluid such as chain-like clusters. In this study, time series variation of the thermal diffusivity of a magnetic fluid caused by applying a magnetic field was investigated experimentally. For the measurement of time series variation of thermal diffusivity, we attempted to apply the forced Rayleigh scattering method (FRSM), which has high temporal and high spatial resolution. We set up an optical system for the FRSM and measured the thermal diffusivity. A magnetic field was applied to a magnetic fluid in parallel and perpendicular to the heat flux direction, and the magnetic field intensity was 70 mT. The FRSM was successfully applied to measurement of the time series variation of the magnetic fluid from applying a magnetic field. The results show that a characteristic configuration in the time series variation of the thermal diffusivity of magnetic fluid was obtained in the case of applying a magnetic field parallel to the heat flux direction. In contrast, in the case of applying a magnetic field perpendicular to the heat flux, the thermal diffusivity of the magnetic fluid hardly changed during measurement. - Highlights: • Thermal diffusivity was measured by forced Rayleigh scattering method (FRSM). • FRSM has high temporal and high spatial resolutions for measurement. • We attempted to apply FRSM to magnetic fluid (MF). • Time series variation of thermal diffusivity of MF was successfully measured by FRSM. • Anisotropic thermal diffusivity of magnetic fluid was also successfully confirmed.
Lempert, Walter R.; Adamovich, Igor V.
2014-10-01
The paper provides an overview of the use of coherent anti-Stokes Raman scattering (CARS) and spontaneous Raman scattering for diagnostics of low-temperature nonequilibrium plasmas and nonequilibrium high-enthalpy flows. A brief review of the theoretical background of CARS, four-wave mixing and Raman scattering, as well as a discussion of experimental techniques and data reduction, are included. The experimental results reviewed include measurements of vibrational level populations, rotational/translational temperature, electric fields in a quasi-steady-state and transient molecular plasmas and afterglow, in nonequilibrium expansion flows, and behind strong shock waves. Insight into the kinetics of vibrational energy transfer, energy thermalization mechanisms and dynamics of the pulse discharge development, provided by these experiments, is discussed. Availability of short pulse duration, high peak power lasers, as well as broadband dye lasers, makes possible the use of these diagnostics at relatively low pressures, potentially with a sub-nanosecond time resolution, as well as obtaining single laser shot, high signal-to-noise spectra at higher pressures. Possibilities for the development of single-shot 2D CARS imaging and spectroscopy, using picosecond and femtosecond lasers, as well as novel phase matching and detection techniques, are discussed.
Coherence effects and average multiplicity in deep inelastic scattering at small χ
International Nuclear Information System (INIS)
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.)
Rayleigh Scattering Density Measurements, Cluster Theory, and Nucleation Calculations at Mach 10
Balla, R. Jeffrey; Everhart, Joel L.
2012-01-01
In an exploratory investigation, quantitative unclustered laser Rayleigh scattering measurements of density were performed in the air in the NASA Langley Research Center's 31 in. Mach 10 wind tunnel. A review of 20 previous years of data in supersonic and Mach 6 hypersonic flows is presented where clustered signals typically overwhelmed molecular signals. A review of nucleation theory and accompanying nucleation calculations are also provided to interpret the current observed lack of clustering. Data were acquired at a fixed stagnation temperature near 990Kat five stagnation pressures spanning 2.41 to 10.0 MPa (350 to 1454 psi) using a pulsed argon fluoride excimer laser and double-intensified charge-coupled device camera. Data averaged over 371 images and 210 pixels along a 36.7mmline measured freestream densities that agree with computed isentropic-expansion densities to less than 2% and less than 6% at the highest and lowest densities, respectively. Cluster-free Mach 10 results are compared with previous clustered Mach 6 and condensation-free Mach 14 results. Evidence is presented indicating vibrationally excited oxygen and nitrogen molecules are absorbed as the clusters form, release their excess energy, and inhibit or possibly reverse the clustering process. Implications for delaying clustering and condensation onset in hypersonic and hypervelocity facilities are discussed.
Evidence of Rayleigh-Taylor instabilities in tri-layer targets
International Nuclear Information System (INIS)
Galmiche, D.; Holstein, P.A.; Meyer, B.; Rostaing, M.; Wilke, N.
1988-01-01
The results of the experiments carried out on a laser system are reported. The work is performed in order to investigate the problem of target instability under ablative acceleration and to get direct evidence of Rayleigh-Taylor instabilities. Tri-layer experiments assert the validity of X-ray spectroscopy measurements as experimental method to investigate the problem. A mixing zone is evidenced and general trends of mixing development versus target acceleration are coherent with numerical simulations. Results obtained with optical smoothing demonstrate that the apparent mixing is not due to large scale illumination non uniformities. Numerical simulations confirm that Rayleigh-Taylor instability seems to be the dominant process responsible for the mixing. Benefit of time resolved spectroscopy appears attractive and gives a real knowledge of the mixing layer
Coherent Raman Scattering Microscopy in Biology and Medicine
Zhang, Chi; Zhang, Delong; Cheng, Ji-Xin
2016-01-01
Advancements in coherent Raman scattering (CRS) microscopy have enabled label-free visualization and analysis of functional, endogenous biomolecules in living systems. When compared with spontaneous Raman microscopy, a key advantage of CRS microscopy is the dramatic improvement in imaging speed, which gives rise to real-time vibrational imaging of live biological samples. Using molecular vibrational signatures, recently developed hyperspectral CRS microscopy has improved the readout of chemical information available from CRS images. In this article, we review recent achievements in CRS microscopy, focusing on the theory of the CRS signal-to-noise ratio, imaging speed, technical developments, and applications of CRS imaging in bioscience and clinical settings. In addition, we present possible future directions that the use of this technology may take. PMID:26514285
Directory of Open Access Journals (Sweden)
M. Alpers
2004-01-01
Full Text Available For the first time, three different temperature lidar methods are combined to obtain time-resolved complete temperature profiles with high altitude resolution over an altitude range from the planetary boundary layer up to the lower thermosphere (about 1–105 km. The Leibniz-Institute of Atmospheric Physics (IAP at Kühlungsborn, Germany (54° N, 12° E operates two lidar instruments, using three different temperature measurement methods, optimized for three altitude ranges: (1 Probing the spectral Doppler broadening of the potassium D1 resonance lines with a tunable narrow-band laser allows atmospheric temperature profiles to be determined at metal layer altitudes (80–105 km. (2 Between about 20 and 90 km, temperatures were calculated from Rayleigh backscattering by air molecules, where the upper start values for the calculation algorithm were taken from the potassium lidar results. Correction methods have been applied to account for, e.g. Rayleigh extinction or Mie scattering of aerosols below about 32 km. (3 At altitudes below about 25 km, backscattering in the Rotational Raman lines is strong enough to obtain temperatures by measuring the temperature dependent spectral shape of the Rotational Raman spectrum. This method works well down to about 1 km. The instrumental configurations of the IAP lidars were optimized for a 3–6 km overlap of the temperature profiles at the method transition altitudes. We present two night-long measurements with clear wave structures propagating from the lower stratosphere up to the lower thermosphere.
International Nuclear Information System (INIS)
Wang, L.; Feng, S.
1989-01-01
The relation between the reflection coefficients and the Green's function for a coherent wave propagation in a disordered elastic-scattering medium is derived. The sum rule of the reflection and transmission coefficients corresponding to probability conservation is shown rigorously for an arbitrary scattering potential. The correlation function of the reflection coefficients is then calculated by using a Feynman-diagrammatic approach in the weak-localized multiple-scattering regime (L much-gt l much-gt λ). The result is in agreement with recent experiments on the so-called ''memory effect'' in reflection coefficients. A more general condition under which the memory effect can occur is derived. Differences between the the correlation functions for reflection and that for transmission are discussed
Energy Technology Data Exchange (ETDEWEB)
Campbell, J.L., E-mail: icampbel@uoguelph.ca [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Perrett, G.M. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Maxwell, J.A. [3A 47 Surrey St. East, Guelph, Ontario, Canada N1H 3P6 (Canada); Nield, E.; Gellert, R. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); King, P.L. [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Lee, M.; O’Meara, J.M.; Pradler, I. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada)
2013-05-01
Spectra from the Mars rover alpha particle X-ray spectrometers contain the elastic and inelastic scatter peaks of the plutonium L X-rays emitted by the instrument’s {sup 244}Cm source. Various spectrum fitting approaches are tested using the terrestrial twin of the APXS instrument on the Mars Science Laboratory Curiosity rover, in order to provide accurate extraction of the Lα and Lβ Compton/Rayleigh intensity ratios, which can provide information about light “invisible” constituents such as water in geological samples. A well-defined dependence of C/R ratios upon mean sample atomic number is established using a large and varied set of geochemical reference materials, and the accuracy of this calibration is examined. Detailed attention is paid to the influence of the rubidium and strontium peaks which overlap the Lα scatter peaks. Our Monte Carlo simulation code for prediction of C/R ratios from element concentrations is updated. The ratio between measured and simulated C/R ratios provides a second means of calibration.
Coherence in electron energy loss spectrometry
International Nuclear Information System (INIS)
Schattschneider, P.; Werner, W.S.M.
2005-01-01
Coherence effects in electron energy loss spectrometry (EELS) and in energy filtering are largely neglected although they occur frequently due to Bragg scattering in crystals. We discuss how coherence in the inelastically scattered wave field can be described by the mixed dynamic form factor (MDFF), and how it relates to the density matrix of the scattered electrons. Among the many aspects of 'inelastic coherence' are filtered high-resolution images, dipole-forbidden transitions, coherence in plasma excitations, errors in chemical microanalysis, coherent double plasmons, and circular dichroism
International Nuclear Information System (INIS)
Lv Yong-Gang; Ji Zi-Heng; Dong Da-Shan; Gong Qi-Huang; Shi Ke-Bin
2015-01-01
We propose and implement a wide-field vibrational phase contrast detection to obtain imaging of imaginary components of third-order nonlinear susceptibility in a coherent anti-Stokes Raman scattering (CARS) microscope with full suppression of the non-resonant background. This technique is based on the unique ability of recovering the phase of the generated CARS signal based on holographic recording. By capturing the phase distributions of the generated CARS field from the sample and from the environment under resonant illumination, we demonstrate the retrieval of imaginary components in the CARS microscope and achieve background free coherent Raman imaging. (paper)
Speckles generated by skewed, short-coherence light beams
International Nuclear Information System (INIS)
Brogioli, D; Salerno, D; Ziano, R; Mantegazza, F; Croccolo, F
2011-01-01
When a coherent laser beam impinges on a random sample (e.g. a colloidal suspension), the scattered light exhibits characteristic speckles. If the temporal coherence of the light source is too short, then the speckles disappear, along with the possibility of performing homodyne or heterodyne scattering detection or photon correlation spectroscopy. Here we investigate the scattering of a so-called ‘skewed coherence beam’, i.e. a short-coherence beam modified such that the field is coherent within slabs that are skewed with respect to the wave fronts. We show that such a beam generates speckles and can be used for heterodyne scattering detection, despite its short temporal coherence. Moreover, we show that the heterodyne signal is not affected by multiple scattering. We suggest that the phenomenon presented here can be used as a means of carrying out heterodyne scattering measurement with any short-coherence radiation, including x-rays. (paper)
Calibration of the ORNL two-dimensional Thomson scattering system
International Nuclear Information System (INIS)
Thomas, C.E. Jr.; Lazarus, E.A.; Kindsfather, R.R.; Murakami, M.; Stewart, K.A.
1985-10-01
A unified presentation of the calibrations needed for accurate calculation of electron temperature and density from Thomson scattering data for the Oak Ridge National Laboratory two-dimensional Thomson scattering system (SCATPAK II) is made. Techniques are described for measuring the range of wavelengths to which each channel is responsive. A statistical method for calibrating the gain of each channel in the system is given, and methods of checking for internal consistency and accuracy are presented. The relationship between the constants describing the relative light collection efficiency of each channel and plasma light-scattering theory is developed, methods for measuring the channel efficiencies and evaluating their accuracy are described, and the effect on these constants of bending fiber optics is discussed. The use of Rayleigh or Raman scattering for absolute efficiency (density) calibration, stray light measurement, and system efficiency evaluation is discussed; the relative merits of Rayleigh vs Raman scattering are presented; and the relationship among the Rayleigh/Raman calibrations, relative channel efficiency constants, and absolute efficiencies is developed
Elastic scattering of gamma radiation in solids
International Nuclear Information System (INIS)
Goncalves, O.D.
1987-01-01
The elastic scattering of gamma rays in solids is studied: Rayleigh scattering as well as Bragg scattering in Laue geometries. We measured Rayleigh cross sections for U, Pb, Pt, W, Sn, Ag, Mo, Cd, Zn, and Cu with gamma energies ranging from 60 to 660 KeV and angles between 5 0 and 140 0 . The experimental data are compared with form factor theories and second order perturbation theories and the limits of validity of both are established. In the 60 KeV experiment, a competition between Rayleigh and Bragg effects is found in the region of low momentum transfer. The Bragg experiments were performed using the gamma ray diffractometer from the Hahn-Meitner Institut (Berlin) with gammas of 317 KeV and angles up to 2 0 . In particular, we studied the effect of annealing in nearly perfect Czochralski Silicon crystals with high perfection in the crystallographic structure. The results are compared with Kinematical and Dynamical theories. (author)
Coherent Electron Scattering Captured by an Attosecond Quantum Stroboscope
International Nuclear Information System (INIS)
Mauritsson, J.; Johnsson, P.; Mansten, E.; Swoboda, M.; Ruchon, T.; L'Huillier, A.; Schafer, K. J.
2008-01-01
We demonstrate a quantum stroboscope based on a sequence of identical attosecond pulses that are used to release electrons into a strong infrared (IR) laser field exactly once per laser cycle. The resulting electron momentum distributions are recorded as a function of time delay between the IR laser and the attosecond pulse train using a velocity map imaging spectrometer. Because our train of attosecond pulses creates a train of identical electron wave packets, a single ionization event can be studied stroboscopically. This technique has enabled us to image the coherent electron scattering that takes place when the IR field is sufficiently strong to reverse the initial direction of the electron motion causing it to rescatter from its parent ion
International Nuclear Information System (INIS)
Patterson, M; Hughes, S
2010-01-01
We introduce a theoretical formalism to describe disorder-induced extrinsic scattering in slow light photonic crystal waveguides. This work details and extends the optical scattering theory used in a recent issue of Physics Review Letters (Patterson et al 2009 Phys. Rev. Lett. 102 253903) to describe coherent scattering phenomena and successfully explain related experimental measurements. Our presented theory, which combines Green function and coupled mode methods, allows us to self-consistently account for arbitrary multiple scattering for the propagating electric field and recover experimental features such as resonances near the band edge. The technique is fully three-dimensional and can calculate the effects of disorder on the propagating field over thousands of unit cells. As an application of this theory, we explore various sample lengths and disordered instances, and demonstrate the profound effect of multiple scattering in the waveguide transmission. The spectra yield rich features associated with disorder-induced localization and multiple scattering, which are shown to be exacerbated in the slow light propagation regime
Tan, Xuanping; Yang, Jidong; Li, Qin; Yang, Qiong; Shen, Yizhong
2016-05-01
Four simple and accurate spectrophotometric methods were proposed for the simultaneous determination of three β-adrenergic blockade, e.g. atenolol, metoprolol and propranolol. The methods were based on the reaction of the three drugs with erythrosine B (EB) in a Britton-Robinson buffer solution at pH 4.6. EB could combine with the drugs to form three ion-association complexes, which resulted in the resonance Rayleigh scattering (RRS) intensity that is enhanced significantly with new RRS peaks that appeared at 337 nm and 370 nm, respectively. In addition, the fluorescence intensity of EB was also quenched. The enhanced scattering intensities of the two peaks and the fluorescence quenched intensity of EB were proportional to the concentrations of the drugs, respectively. What is more, the RRS intensity overlapped with the double-wavelength of 337 nm and 370 nm (so short for DW-RRS) was also proportional to the drugs concentrations. So, a new method with highly sensitive for simultaneous determination of three bisoprolol drugs was established. Finally, the optimum reaction conditions, influencing factors and spectral enhanced mechanism were investigated. The new DW-RRS method has been applied to simultaneously detect the three β-blockers in fresh serum with satisfactory results.
International Nuclear Information System (INIS)
Bito, Kotatsu; Okuno, Masanari; Kano, Hideaki; Leproux, Philippe; Couderc, Vincent; Hamaguchi, Hiro-o
2013-01-01
Highlights: ► We have developed a simultaneous measurement system of CARS and CSRS. ► We can obtain information on the electronic resonance effect with the measurement. ► The simultaneous measurement provides us with more reliable spectral information. - Abstract: We have developed a three-pulse non-degenerate multiplex coherent Raman microspectroscopic system using a white-light laser source. The fundamental output (1064 nm) of a Nd:YAG laser is used for the pump radiation with the white-light laser output (1100–1700 nm) for the Stokes radiation to achieve broadband multiplex excitations of vibrational coherences. The second harmonic (532 nm) of the same Nd:YAG laser is used for the probe radiation. Thanks to the large wavelength difference between the pump and probe radiations, coherent anti-Stokes Raman scattering (CARS) and coherent Stokes Raman scattering (CSRS) can be detected simultaneously. Simultaneous detection of CARS and CSRS enables us to obtain information on the electronic resonance effect that affects differently the CARS and CSRS signals. Simultaneous analysis of the CARS and CSRS signals provides us the imaginary part of χ (3) without introducing any arbitrary parameter in the maximum entropy method (MEM)
Coherent neutrino scattering with low temperature bolometers at Chooz reactor complex
International Nuclear Information System (INIS)
Billard, J; Gascon, J; Jesus, M De; Carr, R; Formaggio, J A; Heine, S T; Johnston, J; Leder, A; Sibille, V; Winslow, L; Dawson, J; Lasserre, T; Figueroa-Feliciano, E; Palladino, K J; Vivier, M
2017-01-01
We present the potential sensitivity of a future recoil detector for a first detection of the process of coherent elastic neutrino nucleus scattering (CE ν NS). We use the Chooz reactor complex in France as our luminous source of reactor neutrinos. Leveraging the ability to cleanly separate the rate correlated with the reactor thermal power against (uncorrelated) backgrounds, we show that a 10 kg cryogenic bolometric array with 100 eV threshold should be able to extract a CE ν NS signal within one year of running. (paper)
Shintake, Tsumoru
2008-10-01
The number of photons produced by coherent x-ray scattering from a single biomolecule is very small because of its extremely small elastic-scattering cross section and low damage threshold. Even with a high x-ray flux of 3 x 10;{12} photons per 100-nm -diameter spot and an ultrashort pulse of 10 fs driven by a future x-ray free electron laser (x-ray FEL), it has been predicted that only a few 100 photons will be produced from the scattering of a single lysozyme molecule. In observations of scattered x rays on a detector, the transfer of energy from wave to matter is accompanied by the quantization of the photon energy. Unfortunately, x rays have a high photon energy of 12 keV at wavelengths of 1A , which is required for atomic resolution imaging. Therefore, the number of photoionization events is small, which limits the resolution of imaging of a single biomolecule. In this paper, I propose a method: instead of directly observing the photons scattered from the sample, we amplify the scattered waves by superimposing an intense coherent reference pump wave on it and record the resulting interference pattern on a planar x-ray detector. Using a nanosized gold particle as a reference pump wave source, we can collect 10;{4}-10;{5} photons in single shot imaging where the signal from a single biomolecule is amplified and recorded as two-dimensional diffraction intensity data. An iterative phase retrieval technique can be used to recover the phase information and reconstruct the image of the single biomolecule and the gold particle at the same time. In order to precisely reconstruct a faint image of the single biomolecule in Angstrom resolution, whose intensity is much lower than that of the bright gold particle, I propose a technique that combines iterative phase retrieval on the reference pump wave and the digital Fourier transform holography on the sample. By using a large number of holography data, the three-dimensional electron density map can be assembled.
SEARCH FOR RAYLEIGH SCATTERING IN THE ATMOSPHERE OF GJ1214b
International Nuclear Information System (INIS)
De Mooij, E. J. W.; Jayawardhana, R.; Brogi, M.; Snellen, I. A. G.; Hoekstra, H.; Otten, G. P. P. L.; Bekkers, D. H.; Haffert, S. Y.; Van Houdt, J. J.; De Kok, R. J.; Croll, B.
2013-01-01
We investigate the atmosphere of GJ1214b, a transiting super-Earth planet with a low mean density, by measuring its transit depth as a function of wavelength in the blue optical portion of the spectrum. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. Most observations favor a water-dominated atmosphere with a small scale-height, however, some observations indicate that GJ1214b could have an extended atmosphere with a cloud layer muting the molecular features. In an atmosphere with a large scale-height, Rayleigh scattering at blue wavelengths is likely to cause a measurable increase in the apparent size of the planet toward the blue. We observed the transit of GJ1214b in the B band with the FOcal Reducing Spectrograph at the Very Large Telescope and in the g band with both ACAM on the William Herschel Telescope (WHT) and the Wide Field Camera at the Isaac Newton Telescope (INT). We find a planet-to-star radius ratio in the B band of 0.1162 ± 0.0017, and in the g band 0.1180 ± 0.0009 and 0.1174 ± 0.0017 for the WHT and INT observations, respectively. These optical data do not show significant deviations from previous measurements at longer wavelengths. In fact, a flat transmission spectrum across all wavelengths best describes the combined observations. When atmospheric models are considered, a small scale-height water-dominated model fits the data best.
Hybrid Rayleigh, Raman and TPE fluorescence spectral confocal microscopy of living cells
Pully, V.V.; Lenferink, Aufrid T.M.; Otto, Cornelis
2010-01-01
A hybrid fluorescence–Raman confocal microscopy platform is presented, which integrates low-wavenumber-resolution Raman imaging, Rayleigh scatter imaging and two-photon fluorescence (TPE) spectral imaging, fast ‘amplitude-only’ TPE-fluorescence imaging and high-spectral-resolution Raman imaging.
Petoukhova, Anna; Steenbergen, Wiendelt; van Leeuwen, Ton; de Mul, F.F.M.
2002-01-01
A low coherence Mach–Zehnder interferometer is developed for path length resolved dynamic light scattering in highly turbid media. The path length distribution of multiply scatteredphotons in Intralipid is changed by the addition of absorbing dyes. Path length distributions obtained for various
Nakamura, Yusuke; Hoshizawa, Taku; Takashima, Yuzuru
2017-09-01
A new method, wavelength diversity detection (WDD), for improving signal quality is proposed and its effectiveness is numerically confirmed. We consider that WDD is especially effective for high-capacity systems having low hologram diffraction efficiencies. In such systems, the signal quality is primarily limited by coherent scattering noise; thus, effective improvement of the signal quality under a scattering-limited system is of great interest. WDD utilizes a new degree of freedom, the spectrum width, and scattering by molecules to improve the signal quality of the system. We found that WDD improves the quality by counterbalancing the degradation of the quality due to Bragg mismatch. With WDD, a higher-scattering-coefficient medium can improve the quality. The result provides an interesting insight into the requirements for material characteristics, especially for a large-M/# material. In general, a larger-M/# material contains more molecules; thus, the system is subject to more scattering, which actually improves the quality with WDD. We propose a pathway for a future holographic data storage system (HDSS) using WDD, which can record a larger amount of data than a conventional HDSS.
Fast analytical scatter estimation using graphics processing units.
Ingleby, Harry; Lippuner, Jonas; Rickey, Daniel W; Li, Yue; Elbakri, Idris
2015-01-01
To develop a fast patient-specific analytical estimator of first-order Compton and Rayleigh scatter in cone-beam computed tomography, implemented using graphics processing units. The authors developed an analytical estimator for first-order Compton and Rayleigh scatter in a cone-beam computed tomography geometry. The estimator was coded using NVIDIA's CUDA environment for execution on an NVIDIA graphics processing unit. Performance of the analytical estimator was validated by comparison with high-count Monte Carlo simulations for two different numerical phantoms. Monoenergetic analytical simulations were compared with monoenergetic and polyenergetic Monte Carlo simulations. Analytical and Monte Carlo scatter estimates were compared both qualitatively, from visual inspection of images and profiles, and quantitatively, using a scaled root-mean-square difference metric. Reconstruction of simulated cone-beam projection data of an anthropomorphic breast phantom illustrated the potential of this method as a component of a scatter correction algorithm. The monoenergetic analytical and Monte Carlo scatter estimates showed very good agreement. The monoenergetic analytical estimates showed good agreement for Compton single scatter and reasonable agreement for Rayleigh single scatter when compared with polyenergetic Monte Carlo estimates. For a voxelized phantom with dimensions 128 × 128 × 128 voxels and a detector with 256 × 256 pixels, the analytical estimator required 669 seconds for a single projection, using a single NVIDIA 9800 GX2 video card. Accounting for first order scatter in cone-beam image reconstruction improves the contrast to noise ratio of the reconstructed images. The analytical scatter estimator, implemented using graphics processing units, provides rapid and accurate estimates of single scatter and with further acceleration and a method to account for multiple scatter may be useful for practical scatter correction schemes.
National Research Council Canada - National Science Library
Roy, Sukesh; Kinnius, Paul J; Lucht, Robert P; Gord, James R
2007-01-01
Time-resolved femtosecond coherent anti-Stokes Raman scattering (fs-CARS) spectroscopy of the nitrogen molecule is used for the measurement of temperature in atmospheric-pressure, near-adiabatic, hydrogen-air diffusion flames...
Hu, Zhongwei; Autschbach, Jochen; Jensen, Lasse
2014-09-28
Resonance hyper-Rayleigh scattering (HRS) of molecules and metal clusters have been simulated based on a time-dependent density functional theory approach. The resonance first-order hyperpolarizability (β) is obtained by implementing damped quadratic response theory using the (2n + 1) rule. To test this implementation, the prototypical dipolar molecule para-nitroaniline (p-NA) and the octupolar molecule crystal violet are used as benchmark systems. Moreover, small silver clusters Ag 8 and Ag 20 are tested with a focus on determining the two-photon resonant enhancement arising from the strong metal transition. Our results show that, on a per atom basis, the small silver clusters possess two-photon enhanced HRS comparable to that of larger nanoparticles. This finding indicates the potential interest of using small metal clusters for designing new nonlinear optical materials.
Ma, Caijuan; Sun, Zijun; Liu, Guihua; Su, Zhengquan; Bai, Yan
2018-02-01
The method was presented for the sensitive and selective determination of chitosan (CTS) in health products with Brilliant Blue (BB) as a probe, based on dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS). In weakly acidic buffer solution, the binding of CTS and BB could result in the RRS intensities getting enhanced significantly at RRS peaks of 344 nm and 452 nm, and the scattering intensities of the two peaks were proportional to the concentration of CTS within a certain range. When the RRS intensities of the two wavelengths were superposed, the results showed higher sensitivity. Under the optimum experimental conditions, the total of the two increased RRS intensities was linear to the CTS concentration in the range of 0.02-1.80 μg/mL and the limit of detection (LOD) was 7.45 ng/mL. In this work, the optimum conditions and the effects of some foreign substances were studied. Accordingly, the new method based on DWO-RRS for the determination of CTS was developed. In addition, the effect of the molecular weight and the deacetylation degree between different chitosan molecules was discussed. Finally, this assay was applied to determine the concentration of CTS in health products with satisfactory results.
Cleff, C.; Gross, P.; Fallnich, C.; Offerhaus, Herman L.; Herek, Jennifer Lynn; Kruse, K.; Beeker, W.P.; Lee, Christopher James; Boller, Klaus J.
2013-01-01
We present a theoretical investigation of stimulated emission pumping to achieve sub-diffraction-limited spatial resolution in coherent anti-Stokes Raman scattering (CARS) microscopy. A pair of control light fields is used to prepopulate the Raman state involved in the CARS process prior to the CARS
International Nuclear Information System (INIS)
Mazzucato, E.
2002-01-01
Localized measurements of short-scale turbulent fluctuations in tokamaks are still an outstanding problem. In this paper, the method of coherent scattering of electromagnetic waves for the detection of density fluctuations is revisited. Results indicate that the proper choice of frequency, size and launching of the probing wave can transform this method into an excellent technique for high-resolution measurements of those fluctuations that plasma theory indicates as the potential cause of anomalous transport in tokamaks. The best spatial resolution can be achieved when the range of scattering angles corresponding to the spectrum of fluctuations under investigation is small. This favors the use of high frequency probing waves, such as those of far infrared lasers. The application to existing large tokamaks is discussed
Coherent anti-Stokes Raman scattering rigid endoscope toward robot-assisted surgery.
Hirose, K; Aoki, T; Furukawa, T; Fukushima, S; Niioka, H; Deguchi, S; Hashimoto, M
2018-02-01
Label-free visualization of nerves and nervous plexuses will improve the preservation of neurological functions in nerve-sparing robot-assisted surgery. We have developed a coherent anti-Stokes Raman scattering (CARS) rigid endoscope to distinguish nerves from other tissues during surgery. The developed endoscope, which has a tube with a diameter of 12 mm and a length of 270 mm, achieved 0.91% image distortion and 8.6% non-uniformity of CARS intensity in the whole field of view (650 μm diameter). We demonstrated CARS imaging of a rat sciatic nerve and visualization of the fine structure of nerve fibers.
Rayleigh's hypothesis and the geometrical optics limit.
Elfouhaily, Tanos; Hahn, Thomas
2006-09-22
The Rayleigh hypothesis (RH) is often invoked in the theoretical and numerical treatment of rough surface scattering in order to decouple the analytical form of the scattered field. The hypothesis stipulates that the scattered field away from the surface can be extended down onto the rough surface even though it is formed by solely up-going waves. Traditionally this hypothesis is systematically used to derive the Volterra series under the small perturbation method which is equivalent to the low-frequency limit. In this Letter we demonstrate that the RH also carries the high-frequency or the geometrical optics limit, at least to first order. This finding has never been explicitly derived in the literature. Our result comforts the idea that the RH might be an exact solution under some constraints in the general case of random rough surfaces and not only in the case of small-slope deterministic periodic gratings.
Energy Technology Data Exchange (ETDEWEB)
Hey, J D
1986-07-01
The optical research of Robert John Strutt, fourth Baron Rayleigh, on the transparency of the terrestrial atmosphere as determined by the distribution of ozone, is reviewed in relation to the studies of Hartley, Cornu, Fabry and Buisson, and Fowler on this subject. It is shown that the basis of Rayleigh's work is now incorporated in the modern optical techniques for atmospheric monitoring.
Monfared, Yashar E.; Ponomarenko, Sergey A.
2017-10-01
We explore theoretically and numerically extreme event excitation in stimulated Raman scattering in gases. We consider gas-filled hollow-core photonic crystal fibers as a particular system realization. We show that moderate amplitude pump fluctuations obeying Gaussian statistics lead to the emergence of heavy-tailed non-Gaussian statistics as coherent seed Stokes pulses are amplified on propagation along the fiber. We reveal the crucial role that coherent memory effects play in causing non-Gaussian statistics of the system. We discover that extreme events can occur even at the initial stage of stimulated Raman scattering when one can neglect energy depletion of an intense, strongly fluctuating Gaussian pump source. Our analytical results in the undepleted pump approximation explicitly illustrate power-law probability density generation as the input pump noise is transferred to the output Stokes pulses.
Elastic scattering of low energy γ-rays
International Nuclear Information System (INIS)
Whittingham, I.B.
1978-01-01
The current status of the theory of the elastic scattering of low energy γ rays is reviewed and a detailed analysis of the theoretical background to the recent calculation of Rayleigh scattering by W.R.Johnson and co-workers is presented
Servali, A.; Long, M. D.; Benoit, M.
2017-12-01
The eastern margin of North America has been affected by a series of mountain building and rifting events that have likely shaped the deep structure of the lithosphere. Observations of seismic anisotropy can provide insight into lithospheric deformation associated with these past tectonic events, as well as into present-day patterns of mantle flow beneath the passive margin. Previous work on SKS splitting beneath eastern North America has revealed fast splitting directions parallel to the strike of the Appalachian orogen in the central and southern Appalachians. A major challenge to the interpretation of SKS splitting measurements, however, is the lack of vertical resolution; isolating anisotropic structures at different depths is therefore difficult. Complementary constraints on the depth distribution of anisotropy can be provided by surface waves. In this study, we analyze the scattering of Love wave energy to Rayleigh waves, which is generated via sharp lateral gradients in anisotropic structure along the ray path. The scattered phases, known as quasi-Love (QL) waves, exhibit amplitude behavior that depend on the strength of the anisotropic contrast as well as the angle between the propagation azimuth and the anisotropic symmetry axis. We analyze data collected by the dense MAGIC seismic array across the central Appalachians. We examine teleseismic earthquakes of magnitude 6.7 and greater over a range of backazimuths, and isolate surface waves at periods between 100 and 500 seconds. We compare the data to synthetic seismograms generated by the Princeton Global ShakeMovie initiative to identify anomalous QL arrivals. We find evidence significant QL arrivals at MAGIC stations, with amplitudes depending on propagation azimuth and station location. Preliminary results are consistent with a sharp lateral gradient in seismic anisotropy across the Appalachian Mountains in the depth range between 100-200 km.
International Nuclear Information System (INIS)
Chan, W K; Schwartz, J; Flanagan, G
2013-01-01
One of the key remaining challenges to safe and reliable operation of large, high temperature superconductor (HTS)-based magnet systems is quench detection and protection. Due to the slow quench propagation in HTS systems, the conventional discrete voltage-tap approach developed for NbTi and Nb 3 Sn magnets may not be sufficient. In contrast, a distributed temperature profile, generated by a distributed temperature sensor and facilitating continuous monitoring of the temperature at any monitored locations within a magnet with high spatial resolution, may be required. One such distributed temperature sensing option is the use of Rayleigh-based fiber optic sensors (FOS), which are immune to electromagnetic interference. The detection of a quench via Rayleigh-based FOS relies on converting the spectral shifts in the Rayleigh scattering spectra into temperature variations. As a result, the higher the spatial sampling resolution the larger the data processing volume, and thus the lower the temporal sampling resolution. So, for effective quench detection, which requires the quick and accurate identification of a hot spot, it is important to find a balance between the spatial and temporal resolutions executable on a given data acquisition and processing (DAQ) system. This paper discusses a method for finding an appropriate DAQ technology that matches the characteristic of a superconducting coil, and determining the acceptable resolutions for efficient and safe quench detection. A quench detection algorithm based on distributed temperature sensing is proposed and its implementation challenges are discussed. (paper)
Energy Technology Data Exchange (ETDEWEB)
Morris, R [Durham, NC (United States); Lakshmanan, M; Fong, G; Kapadia, A [Carl E Ravin Advanced Imaging Laboratories, Durham, NC (United States); Greenberg, J [Duke University, Durham, NC (United States)
2016-06-15
Purpose: Coherent scatter based imaging has shown improved contrast and molecular specificity over conventional digital mammography however the biological risks have not been quantified due to a lack of accurate information on absorbed dose. This study intends to characterize the dose distribution and average glandular dose from coded aperture coherent scatter spectral imaging of the breast. The dose deposited in the breast from this new diagnostic imaging modality has not yet been quantitatively evaluated. Here, various digitized anthropomorphic phantoms are tested in a Monte Carlo simulation to evaluate the absorbed dose distribution and average glandular dose using clinically feasible scan protocols. Methods: Geant4 Monte Carlo radiation transport simulation software is used to replicate the coded aperture coherent scatter spectral imaging system. Energy sensitive, photon counting detectors are used to characterize the x-ray beam spectra for various imaging protocols. This input spectra is cross-validated with the results from XSPECT, a commercially available application that yields x-ray tube specific spectra for the operating parameters employed. XSPECT is also used to determine the appropriate number of photons emitted per mAs of tube current at a given kVp tube potential. With the implementation of the XCAT digital anthropomorphic breast phantom library, a variety of breast sizes with differing anatomical structure are evaluated. Simulations were performed with and without compression of the breast for dose comparison. Results: Through the Monte Carlo evaluation of a diverse population of breast types imaged under real-world scan conditions, a clinically relevant average glandular dose for this new imaging modality is extrapolated. Conclusion: With access to the physical coherent scatter imaging system used in the simulation, the results of this Monte Carlo study may be used to directly influence the future development of the modality to keep breast dose to
A Micropulse eye-safe all-fiber molecular backscatter coherent temperature lidar
Directory of Open Access Journals (Sweden)
Abari Cyrus F.
2016-01-01
Full Text Available In this paper, we analyze the performance of an all-fiber, micropulse, 1.5 μm coherent lidar for remote sensing of atmospheric temperature. The proposed system benefits from the recent advances in optics/electronics technology, especially an all-fiber image-reject homodyne receiver, where a high resolution spectrum in the baseband can be acquired. Due to the presence of a structured spectra resulting from the spontaneous Rayleigh-Brillouine scattering, associated with the relevant operating regimes, an accurate estimation of the temperature can be carried out. One of the main advantages of this system is the removal of the contaminating Mie backscatter signal by electronic filters at the baseband (before signal conditioning and amplification. The paper presents the basic concepts as well as a Monte-Carlo system simulation as the proof of concept.
Phonons in Solid Hydrogen and Deuterium Studied by Inelastic Coherent Neutron Scattering
DEFF Research Database (Denmark)
Nielsen, Mourits
1973-01-01
Phonon dispersion relations have been measured by coherent neutron scattering in solid para-hydrogen and ortho-deuterium. The phonon energies are found to be nearly equal in the two solids, the highest energy in each case lying close to 10 meV. The pressure and temperature dependence of the phonon...... energies have been measured in ortho-deuterium and the lattice change determined by neutron diffraction. When a pressure of 275 bar is applied, the phonon energies are increased by about 10%, and heating the crystal to near the melting point decreases them by about 7%. The densities of states, the specific...... heats, and the Debye temperatures have been deduced and found to be in agreement with the published experimental results. The Debye temperatures are 118 K for hydrogen and 114 K for deuterium. For hydrogen the Debye-Waller factor has been measured by incoherent neutron scattering and it corresponds...
Energy Technology Data Exchange (ETDEWEB)
Zhou, Xiang; Zhang, Zhenyu [Wuhan University, Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan (China); Liu, Qian; Zheng, Yangheng [University of Chinese Academy of Sciences, School of Physics, Beijing (China); Han, Junbo [Huazhong University of Science and Technology, Wuhan National High Magnetic Field Center, Wuhan (China); Zhang, Xuan; Ding, Yayun; Zhou, Li; Cao, Jun; Wang, Yifang [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)
2015-11-15
We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√(E(MeV)) required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Zhou, Xiang, E-mail: xiangzhou@whu.edu.cn [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, 430072, Wuhan (China); Liu, Qian, E-mail: liuqian@ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, 100049, Beijing (China); Han, Junbo [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan (China); Zhang, Zhenyu [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, 430072, Wuhan (China); Zhang, Xuan; Ding, Yayun [Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing (China); Zheng, Yangheng [School of Physics, University of Chinese Academy of Sciences, 100049, Beijing (China); Zhou, Li; Cao, Jun; Wang, Yifang [Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing (China)
2015-11-21
We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√(E(MeV)) required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments.
Energy Technology Data Exchange (ETDEWEB)
Morris, R; Albanese, K; Lakshmanan, M; Greenberg, J; Kapadia, A [Duke University Medical Center, Durham, NC, Carl E Ravin Advanced Imaging Laboratories, Durham, NC (United States)
2015-06-15
Purpose: This study intends to characterize the spectral and spatial resolution limits of various fan beam geometries for differentiation of normal and neoplastic breast structures via coded aperture coherent scatter spectral imaging techniques. In previous studies, pencil beam raster scanning methods using coherent scatter computed tomography and selected volume tomography have yielded excellent results for tumor discrimination. However, these methods don’t readily conform to clinical constraints; primarily prolonged scan times and excessive dose to the patient. Here, we refine a fan beam coded aperture coherent scatter imaging system to characterize the tradeoffs between dose, scan time and image quality for breast tumor discrimination. Methods: An X-ray tube (125kVp, 400mAs) illuminated the sample with collimated fan beams of varying widths (3mm to 25mm). Scatter data was collected via two linear-array energy-sensitive detectors oriented parallel and perpendicular to the beam plane. An iterative reconstruction algorithm yields images of the sample’s spatial distribution and respective spectral data for each location. To model in-vivo tumor analysis, surgically resected breast tumor samples were used in conjunction with lard, which has a form factor comparable to adipose (fat). Results: Quantitative analysis with current setup geometry indicated optimal performance for beams up to 10mm wide, with wider beams producing poorer spatial resolution. Scan time for a fixed volume was reduced by a factor of 6 when scanned with a 10mm fan beam compared to a 1.5mm pencil beam. Conclusion: The study demonstrates the utility of fan beam coherent scatter spectral imaging for differentiation of normal and neoplastic breast tissues has successfully reduced dose and scan times whilst sufficiently preserving spectral and spatial resolution. Future work to alter the coded aperture and detector geometries could potentially allow the use of even wider fans, thereby making coded
The upgrade of the Thomson scattering system for measurement on the C-2/C-2U devices
Energy Technology Data Exchange (ETDEWEB)
Zhai, K.; Schindler, T.; Kinley, J.; Deng, B.; Thompson, M. C. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States)
2016-11-15
The C-2/C-2U Thomson scattering system has been substantially upgraded during the latter phase of C-2/C-2U program. A Rayleigh channel has been added to each of the three polychromators of the C-2/C-2U Thomson scattering system. Onsite spectral calibration has been applied to avoid the issue of different channel responses at different spots on the photomultiplier tube surface. With the added Rayleigh channel, the absolute intensity response of the system is calibrated with Rayleigh scattering in argon gas from 0.1 to 4 Torr, where the Rayleigh scattering signal is comparable to the Thomson scattering signal at electron densities from 1 × 10{sup 13} to 4 × 10{sup 14} cm{sup −3}. A new signal processing algorithm, using a maximum likelihood method and including detailed analysis of different noise contributions within the system, has been developed to obtain electron temperature and density profiles. The system setup, spectral and intensity calibration procedure and its outcome, data analysis, and the results of electron temperature/density profile measurements will be presented.
Gu, Mingming; Satija, Aman; Lucht, Robert P.
2018-01-01
The effects of moderate levels of chirp in the pump and Stokes pulses on chirped-probe-pulse femtosecond coherent anti-Stokes Raman scattering (CPP fs CARS) were investigated. The frequency chirp in the pump and Stokes pulses was introduced
International Nuclear Information System (INIS)
Farkullin, M.N.; Nikitin, M.A.; Kashchenko, N.M.
1989-01-01
Calculations of linear increment of the Rayleigh-Taylor instability for various geophysical conditions are presented. It is shwn that space-time characteristics of increment depend strongly on conditions of solar activity and seasons. The calculation results are in a good agreement with statistical regularities of F-scattering observation in equatorial F-area, which points to the Rayleigh-Taylor natur of the penomena
Tay, Benjamin Chia-Meng; Chow, Tzu-Hao; Ng, Beng-Koon; Loh, Thomas Kwok-Seng
2012-09-01
This study investigates the autocorrelation bandwidths of dual-window (DW) optical coherence tomography (OCT) k-space scattering profile of different-sized microspheres and their correlation to scatterer size. A dual-bandwidth spectroscopic metric defined as the ratio of the 10% to 90% autocorrelation bandwidths is found to change monotonically with microsphere size and gives the best contrast enhancement for scatterer size differentiation in the resulting spectroscopic image. A simulation model supports the experimental results and revealed a tradeoff between the smallest detectable scatterer size and the maximum scatterer size in the linear range of the dual-window dual-bandwidth (DWDB) metric, which depends on the choice of the light source optical bandwidth. Spectroscopic OCT (SOCT) images of microspheres and tonsil tissue samples based on the proposed DWDB metric showed clear differentiation between different-sized scatterers as compared to those derived from conventional short-time Fourier transform metrics. The DWDB metric significantly improves the contrast in SOCT imaging and can aid the visualization and identification of dissimilar scatterer size in a sample. Potential applications include the early detection of cell nuclear changes in tissue carcinogenesis, the monitoring of healing tendons, and cell proliferation in tissue scaffolds.
Rao, D. V.; Takeda, T.; Itai, Y.; Akatsuka, T.; Seltzer, S. M.; Hubbell, J. H.; Cesareo, R.; Brunetti, A.; Gigante, G. E.
Atomic Rayleigh scattering cross-sections for low, medium and high Z atoms are measured in vacuum using X-ray tube with a secondary target as an excitation source instead of radioisotopes. Monoenergetic Kα radiation emitted from the secondary target and monoenergetic radiation produced using two secondary targets with filters coupled to an X-ray tube are compared. The Kα radiation from the second target of the system is used to excite the sample. The background has been reduced considerably and the monochromacy is improved. Elastic scattering of Kα X-ray line energies of the secondary target by the sample is recorded with Hp Ge and Si (Li) detectors. A new approach is developed to estimate the solid angle approximation and geometrical efficiency for a system with experimental arrangement using X-ray tube and secondary target. The variation of the solid angle is studied by changing the radius and length of the collimators towards and away from the source and sample. From these values the variation of the total solid angle and geometrical efficiency is deduced and the optimum value is used for the experimental work. The efficiency is larger because the X-ray fluorescent source acts as a converter. Experimental results based on this system are compared with theoretical estimates and good agreement is observed in between them.
Coherent Raman scattering microscopy for label-free imaging of live amphioxus
Yu, Zhilong; Chen, Tao; Zhang, Xiannian; Shen, Jie; Chen, Junyuan; Huang, Yanyi
2012-03-01
The existence of notochord distinguishes chordates from other phyla. Amphioxus is the only animal that keeps notochord during the whole life. Notochord is a unique organ for amphioxus, with its vertically arranged muscular notochordal plates, which is different from notochords in embryos of other chordates. We use stimulated Raman scattering (SRS) microscopy as a non-invasive technique to image the chemical components in amphioxus notochord. SRS provides chemical specificity as spontaneous Raman does and offers a higher sensitivity for fast acquisition. Unlike coherent anti- Stokes Raman scattering (CARS) microscopy, SRS microscopy doesn't have non-resonant background and can better differentiate different components in the specimen. We verify that the notochord is a protein-rich organ, which agrees well with the result of conventional staining methods. Detailed structures in notochordal plates and notochordal sheath are revealed by SRS microscopy with diffraction limited resolution. Our experiment shows that SRS microscopy is an excellent imaging tool for biochemical research with its intrinsic chemical selectivity, high spatiotemporal resolution and native 3D optical sectioning ability.
Turbulent thermal superstructures in Rayleigh-Bénard convection
Stevens, Richard J. A. M.; Blass, Alexander; Zhu, Xiaojue; Verzicco, Roberto; Lohse, Detlef
2018-04-01
We report the observation of superstructures, i.e., very large-scale and long living coherent structures in highly turbulent Rayleigh-Bénard convection up to Rayleigh Ra=109 . We perform direct numerical simulations in horizontally periodic domains with aspect ratios up to Γ =128 . In the considered Ra number regime the thermal superstructures have a horizontal extend of six to seven times the height of the domain and their size is independent of Ra. Many laboratory experiments and numerical simulations have focused on small aspect ratio cells in order to achieve the highest possible Ra. However, here we show that for very high Ra integral quantities such as the Nusselt number and volume averaged Reynolds number only converge to the large aspect ratio limit around Γ ≈4 , while horizontally averaged statistics such as standard deviation and kurtosis converge around Γ ≈8 , the integral scale converges around Γ ≈32 , and the peak position of the temperature variance and turbulent kinetic energy spectra only converge around Γ ≈64 .
International Nuclear Information System (INIS)
Pereira, Marcelo O.; Conti, Claudio de Carvalho; Anjos, Marcelino J.; Lopes, Ricardo T.
2011-01-01
The aim of this work was to develop a new method to correct the absorbed radiation (the mass attenuation coefficient curve) in low energy (E B O 3 , Na 2 CO 3 , CaCO 3 , Al 2 O 3 , K 2 SO 4 and MgO) of radiation produced by a gamma-ray source of Am-241(59.54 keV) also applied to certified biological samples of milk powder, hay powder and bovine liver (NIST 155 7B). In addition, six methods of effective atomic number determination were used as described in literature to determinate the Rayleigh to Compton scattering ratio (R/C) , in order to calculate the mass attenuation coefficient. The results obtained by the proposed method were compared with those obtained using the transmission method. The experimental results were in good agreement with transmission values suggesting that the method to correct radiation absorption presented in this paper is adequate for biological samples. (author)
Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds
Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan; Williams, Oliver; Watson, Peter; Langbein, Wolfgang; Borri, Paola
2014-11-01
Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing fluorescent defect centres with stable optical properties. Here, we show that single non-fluorescing nanodiamonds exhibit strong coherent anti-Stokes Raman scattering (CARS) at the sp3 vibrational resonance of diamond. Using correlative light and electron microscopy, the relationship between CARS signal strength and nanodiamond size is quantified. The calibrated CARS signal in turn enables the analysis of the number and size of nanodiamonds internalized in living cells in situ, which opens the exciting prospect of following complex cellular trafficking pathways quantitatively.
Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds.
Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan; Williams, Oliver; Watson, Peter; Langbein, Wolfgang; Borri, Paola
2014-11-01
Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing fluorescent defect centres with stable optical properties. Here, we show that single non-fluorescing nanodiamonds exhibit strong coherent anti-Stokes Raman scattering (CARS) at the sp(3) vibrational resonance of diamond. Using correlative light and electron microscopy, the relationship between CARS signal strength and nanodiamond size is quantified. The calibrated CARS signal in turn enables the analysis of the number and size of nanodiamonds internalized in living cells in situ, which opens the exciting prospect of following complex cellular trafficking pathways quantitatively.
Coherent band excitations in CePd3: A comparison of neutron scattering and ab initio theory.
Goremychkin, Eugene A; Park, Hyowon; Osborn, Raymond; Rosenkranz, Stephan; Castellan, John-Paul; Fanelli, Victor R; Christianson, Andrew D; Stone, Matthew B; Bauer, Eric D; McClellan, Kenneth J; Byler, Darrin D; Lawrence, Jon M
2018-01-12
In common with many strongly correlated electron systems, intermediate valence compounds are believed to display a crossover from a high-temperature regime of incoherently fluctuating local moments to a low-temperature regime of coherent hybridized bands. We show that inelastic neutron scattering measurements of the dynamic magnetic susceptibility of CePd 3 provides a benchmark for ab initio calculations based on dynamical mean field theory. The magnetic response is strongly momentum dependent thanks to the formation of coherent f-electron bands at low temperature, with an amplitude that is strongly enhanced by local particle-hole interactions. The agreement between experiment and theory shows that we have a robust first-principles understanding of the temperature dependence of f-electron coherence. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
Coherent anti-Stokes Raman scattering spectroscope/microscope based on a widely tunable laser source
Dementjev, A.; Gulbinas, V.; Serbenta, A.; Kaucikas, M.; Niaura, G.
2010-03-01
We present a coherent anti-Stokes Raman scattering (CARS) microscope based on a robust and simple laser source. A picosecond laser operating in a cavity dumping regime at the 1 MHz repetition rate was used to pump a traveling wave optical parametric generator, which serves as a two-color excitation light source for the CARS microscope. We demonstrate the ability of the presented CARS microscope to measure CARS spectra and images by using several detection schemes.
Reconstruction of surface morphology from coherent scattering of white x-ray radiation
Energy Technology Data Exchange (ETDEWEB)
Sant, Tushar; Pietsch, Ullrich [Solid State Physics Group, University of Siegen, 57068 Siegen (Germany)
2009-07-01
Static speckle experiments were performed using coherent white X-ray radiation from a bending magnet at BESSYII. Semiconductor and polymer surfaces were investigated under incidence condition smaller than the critical angle of total external reflection. The scattering pattern of the sample results from the illumination function modified by the surface roughness. The periodic oscillations are caused by the illumination function whereas other irregular features are associated with sample surface. The speckle map of reflection from a laterally periodic structure like GaAs grating is studied. Under coherent illumination the grating peaks split into speckles because of fluctuations on the sample surface. The surface morphology can be reconstructed using phase retrieval algorithms. In case of 1D problem, these algorithms rarely yield a unique and converging solution. The algorithm is modified to contain additional propagator term and the phase of illumination function in the real space constraint. The modified algorithm converges faster than conventional algorithms. A detailed surface profiles from the real measurements of the sample are reconstructed using this algorithm.
Discrete ordinate theory of radiative transfer. 2: Scattering from maritime haze
Kattawar, G. W.; Plass, G. N.; Catchings, F. E.
1971-01-01
Discrete ordinate theory was used to calculate the reflected and transmitted radiance of photons which have interacted with plane parallel maritime haze layers. The results are presented for three solar zenith angles, three values of the surface albedo, and a range of optical thicknesses from very thin to very thick. The diffuse flux at the lower boundary and the cloud albedo were tabulated. The forward peak and other features in the single scattered phase function caused the radiance in many cases to be very different from that for Rayleigh scattering. The variation of the radiance with both the zenith or nadir angle and the azimuthal angle is more marked, and the relative limb darkening under very thick layers is greater, for haze than for Rayleigh scattering. The downward diffuse flux at the lower boundary for A = O is always greater and the cloud albedo is always less for haze than for Rayleigh layers.
Rayleigh wave ellipticity across the Iberian Peninsula and Morocco
Gómez García, Clara; Villaseñor, Antonio
2015-04-01
Spectral amplitude ratios between horizontal and vertical components (H/V ratios) from seismic records are useful to evaluate site effects, predict ground motion and invert for S velocity in the top several hundred meters. These spectral ratios can be obtained from both ambient noise and earthquakes. H/V ratios from ambient noise depend on the content and predominant wave types: body waves, Rayleigh waves, a mixture of different waves, etc. The H/V ratio computed in this way is assumed to measure Rayleigh wave ellipticity since ambient vibrations are dominated by Rayleigh waves. H/V ratios from earthquakes are able to determine the local crustal structure at the vicinity of the recording station. These ratios obtained from earthquakes are based on surface wave ellipticity measurements. Although long period (>20 seconds) Rayleigh H/V ratio is not currently used because of large scatter has been reported and uncertainly about whether these measurements are compatible with traditional phase and group velocity measurements, we will investigate whether it is possible to obtain stable estimates after collecting statistics for many earthquakes. We will use teleseismic events from shallow earthquakes (depth ≤ 40 km) between 2007 January 1 and 2012 December 31 with M ≥ 6 and we will compute H/V ratios for more than 400 stations from several seismic networks across the Iberian Peninsula and Morocco for periods between 20 and 100 seconds. Also H/V ratios from cross-correlations of ambient noise in different components for each station pair will be computed. Shorter period H/V ratio measurements based on ambient noise cross-correlations are strongly sensitive to near-surface structure, rather than longer period earthquake Rayleigh waves. The combination of ellipticity measurements based on earthquakes and ambient noise will allow us to perform a joint inversion with Rayleigh wave phase velocity. Upper crustal structure is better constrained by the joint inversion compared
Direction dependent Love and Rayleigh wave noise characteristics using multiple arrays across Europe
Juretzek, Carina; Perleth, Magdalena; Hadziioannou, Celine
2016-04-01
Seismic noise has become an important signal source for tomography and monitoring purposes. Better understanding of the noise field characteristics is crucial to further improve noise applications. Our knowledge about common and different origins of Love and Rayleigh waves in the microseism band is still limited. This applies in particular for constraints on source locations and source mechanisms of Love waves. Here, 3-component beamforming is used to distinguish between the different polarized wave types in the primary and secondary microseism noise field recorded at several arrays across Europe. We compare characteristics of Love and Rayleigh wave noise, such as source directions and frequency content. Further, Love to Rayleigh wave ratios are measured and a dependence on direction is found, especially in the primary microseism band. Estimates of the kinetic energy density ratios propose a dominance of coherent Love waves in the primary, but not in the secondary microseism band. The seasonality of the noise field characteristics is examined by using a full year of data in 2013 and is found to be stable.
Coherent band excitations in CePd_{3}: A comparison of neutron scattering and ab initio theory
Energy Technology Data Exchange (ETDEWEB)
Goremychkin, Eugene A. [Joint Institute for Nuclear Research, Dubna (Russia). Frank Laboratory of Neutron Physics; Park, Hyowon [Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Univ. of Chicago, IL (United States). Department of Physics; Osborn, Raymond [Argonne National Lab. (ANL), Argonne, IL (United States); Rosenkranz, Stephan [Argonne National Lab. (ANL), Argonne, IL (United States); Castellan, John-Paul [Argonne National Lab. (ANL), Argonne, IL (United States); Karlsruhe Institute of Technology (Germany). Institute for Solid State Physics; Fanelli, Victor R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Instrument and Source Division; Christianson, Andrew D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division; Stone, Matthew B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division; Bauer, Eric D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); McClellan, Kenneth J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Byler, Darrin D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lawrence, Jon M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy
2018-01-12
In common with many strongly correlated electron systems, intermediate valence compounds are believed to display a crossover from a high-temperature regime of incoherently fluctuating local moments to a low-temperature regime of coherent hybridized bands. In this work, we show that inelastic neutron scattering measurements of the dynamic magnetic susceptibility of CePd_{3} provides a benchmark for ab initio calculations based on dynamical mean field theory. The magnetic response is strongly momentum dependent thanks to the formation of coherent f-electron bands at low temperature, with an amplitude that is strongly enhanced by local particle-hole interactions. Finally, the agreement between experiment and theory shows that we have a robust first-principles understanding of the temperature dependence of f-electron coherence.
Scattering of light and other electromagnetic radiation
Kerker, Milton
1969-01-01
The Scattering of Light and Other Electromagnetic Radiation discusses the theory of electromagnetic scattering and describes some practical applications. The book reviews electromagnetic waves, optics, the interrelationships of main physical quantities and the physical concepts of optics, including Maxwell's equations, polarization, geometrical optics, interference, and diffraction. The text explains the Rayleigh2 theory of scattering by small dielectric spheres, the Bessel functions, and the Legendre functions. The author also explains how the scattering functions for a homogenous sphere chan
Coherent methods in X-ray scattering
International Nuclear Information System (INIS)
Gorobtsov, Oleg
2017-05-01
X-ray radiation has been used to study structural properties of materials for more than a hundred years. Construction of extremely coherent and bright X-ray radiation sources such as free electron lasers (FELs) and latest generationstorage rings led to rapid development of experimental methods relying on high radiation coherence. These methods allow to perform revolutionary studies in a wide range of fields from solid state physics to biology. In this thesis I focus on several important problems connected with the coherent methods. The first part considers applications of dynamical diffraction theory on crystals to studies with coherent X-ray radiation. It presents the design of a high-resolution spectrometer for free electron lasers that should allow to resolve spectral structure of individual FEL pulses. The spectrometer is based on the principle of dynamical diffraction focusing. The knowledge of individual FEL pulse spectra is necessary for understanding FEL longitudinal coherence. In the same part I present quasi-kinematical approximation to dynamical theory which allows to treat analytically phase effects observed in X-ray coherent imaging on nanocrystals. These effects may play a big role when methods such as ptychography are used to study crystalline samples. The second part deals with measurements of FEL coherence properties using intensity - intensity interferometry. Results of several experiments performed at FELs FLASH and LCLS are revealed in this section. I have developed models and theories to explain the behavior observed in experiments on FLASH. These models allowed to extract information about external positional jitter of FEL pulses and secondary beams present in FEL radiation. In the LCLS experiment the Hanbury Brown and Twiss type interferometry was performed on Bragg peaks from colloidal crystal. This did not require additional measurements without the sample and information was extracted directly from diffraction patterns. Therefore intensity
Coherent methods in X-ray scattering
Energy Technology Data Exchange (ETDEWEB)
Gorobtsov, Oleg
2017-05-15
X-ray radiation has been used to study structural properties of materials for more than a hundred years. Construction of extremely coherent and bright X-ray radiation sources such as free electron lasers (FELs) and latest generationstorage rings led to rapid development of experimental methods relying on high radiation coherence. These methods allow to perform revolutionary studies in a wide range of fields from solid state physics to biology. In this thesis I focus on several important problems connected with the coherent methods. The first part considers applications of dynamical diffraction theory on crystals to studies with coherent X-ray radiation. It presents the design of a high-resolution spectrometer for free electron lasers that should allow to resolve spectral structure of individual FEL pulses. The spectrometer is based on the principle of dynamical diffraction focusing. The knowledge of individual FEL pulse spectra is necessary for understanding FEL longitudinal coherence. In the same part I present quasi-kinematical approximation to dynamical theory which allows to treat analytically phase effects observed in X-ray coherent imaging on nanocrystals. These effects may play a big role when methods such as ptychography are used to study crystalline samples. The second part deals with measurements of FEL coherence properties using intensity - intensity interferometry. Results of several experiments performed at FELs FLASH and LCLS are revealed in this section. I have developed models and theories to explain the behavior observed in experiments on FLASH. These models allowed to extract information about external positional jitter of FEL pulses and secondary beams present in FEL radiation. In the LCLS experiment the Hanbury Brown and Twiss type interferometry was performed on Bragg peaks from colloidal crystal. This did not require additional measurements without the sample and information was extracted directly from diffraction patterns. Therefore intensity
International Nuclear Information System (INIS)
Puumalainen, P.; Uimarihuhta, A.; Olkkonen, H.
1982-01-01
Results showed that the x-ray generator could be used as a radiation source in the coherent/Compton scattering method of measuring trabecular bone mineral content. The quasimonoenergetic x-ray beam was produced from the continuous bremsstrahlung radiation with the aid of a spectral filter. Of the two measuring arrangements that were tested, the semiconductor detector geometry appeared to give distinctly more reproducible results than the two NaI detector system. However, to improve the counting efficiency of the coherent radiation, the 'coherent' NaI detector could be replaced by a bore-through scintillation probe (bore diameter about 10mm). By placing the x-ray fluorescence target inside the bore, the yield would be considerably higher. The present method is suitable for TBMC measurements of small animal and human peripheral bones. Errors are discussed in relation to increase of bone size. (U.K.)
Coherent Raman scattering in high-pressure/high-temperature fluids: An overview
International Nuclear Information System (INIS)
Schmidt, S.C.; Moore, D.S.
1990-01-01
The present understanding of high-pressure/high-temperature dense-fluid behavior is derived almost exclusively from hydrodynamic and thermodynamic measurements. Such results average over the microscopic aspects of the materials and are, therefore, insufficient for a complete understanding of fluid behavior. At the present, dense-fluid models can be verified only to the extend that they agree with the macroscopic measurements. Recently, using stimulated Raman scattering, Raman induced Kerr effect scattering, and coherent anti-Stokes Raman scattering, we have been able to probe some of the microscopic phenomenology of these dense fluids. In this paper, we discuss primarily the use of CARS in conjunction with a two-stage light-gas gun to obtain vibrational spectra of shock-compressed liquid N 2 , O 2 , CO, their mixtures, CH 3 NO 2 , and N 2 O. These experimental spectra are compared to synthetic spectra calculated using a semiclassical model for CARS intensities and best fit vibrational frequencies, peak Raman susceptibilities, and Raman linewidths. For O 2 , the possibility of resonance enhancement from collision-induced absorption is addressed. Shifts in the vibrational frequencies reflect the influence of increased density and temperature on the intramolecular motion. The derived parameters suggest thermal equilibrium of the vibrational levels is established less than a few nanoseconds after shock passage. Vibrational temperatures are obtained that agree with those derived from equation-of-state calculations. Measured linewidths suggest that vibrational dephasing times have decreased to subpicosecond values at the highest shock pressures
Rayleigh scattering for a magnetized cold plasma sphere
International Nuclear Information System (INIS)
Li Yingle; Wang Mingjun; Tang Gaofeng; Li Jin
2010-01-01
The transformation of parameter tensors for anisotropic medium in different coordinate systems is derived. The electric field for a magnetized cold plasma sphere and the general expression of scattering field from anisotropic target are obtained. The functional relations of differential scattering cross section and the radar cross section for the magnetized plasma sphere are presented. Simulation results agree with that in the literatures, which shows the method used is correct and therefore the results may provide a theoretical base for anisotropic target identification. (authors)
Nonstationary interference and scattering from random media
International Nuclear Information System (INIS)
Nazikian, R.
1991-12-01
For the small angle scattering of coherent plane waves from inhomogeneous random media, the three dimensional mean square distribution of random fluctuations may be recovered from the interferometric detection of the nonstationary modulational structure of the scattered field. Modulational properties of coherent waves scattered from random media are related to nonlocal correlations in the double sideband structure of the Fourier transform of the scattering potential. Such correlations may be expressed in terms of a suitability generalized spectral coherence function for analytic fields
Energy Technology Data Exchange (ETDEWEB)
Gholamrezaie, Fatemeh; Meskers, Stefan C. J., E-mail: s.c.j.meskers@tue.nl [Molecular Materials and Nanosystems and Institute of Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Leeuw, Dago M. de [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany)
2016-06-07
Scattering matrix theory is used to describe resonant optical properties of molecular monolayers. Three types of coupling are included: exciton-exciton, exciton-photon, and exciton-phonon coupling. We use the K-matrix formalism, developed originally to describe neutron scattering spectra in nuclear physics to compute the scattering of polaritons by phonons. This perturbation approach takes into account the three couplings and allows one to go beyond molecular exciton theory without the need of introducing additional boundary conditions for the polariton. We demonstrate that reflection, absorption, and extinction of light by 2D self-assembled monolayers of molecules containing quinque-thiophene chromophoric groups can be calculated. The extracted coherence length of the Frenkel exciton is discussed.
International Nuclear Information System (INIS)
Gigante, G.E.; Sciuti, S.
1985-01-01
In this paper, experiments and related theoretical deductions on coherent/Compton scattering of 59.5-keV Am241 gamma line by bonelike materials are described. In particular, the authors demonstrate that a photon scattering mineralometer (PSM) can attain the best working conditions when it operates in a backscattering geometry mode. In fact, the large scattering angle they chose, theta = 135 degrees, allowed them to assemble a very compact source-detector device. Further, the relative sensitivity at 135 degrees turns out to be congruent to 1.7 and congruent to 6 times bigger than at 90 degrees and 45 degrees, respectively. The performances of the theta = 135 degrees PSM were experimentally investigated; i.e., in a measuring time of 10(3) s, a congruent to 5% statistical precision for bonelike materials, such as K 2 HPO 4 -water solutions, was obtained. The large-angle PSM device seems to be very promising for trabecular bone mineral density measurements in vivo in peripheral anatomic sites
Liang, Aihui; Peng, Jing; Liu, Qingye; Wen, Guiqing; Lu, Zhujun; Jiang, Zhiliang
2015-08-15
In pH 4.0 acetate buffer solution, fluorine ions react with fluorine reagent (FR) and La(III) to generate blue ternary complex that exhibited strong absorption at about 370 nm. Upon addition of graphene oxide/nanogold (GO/NG) as resonance Rayleigh scattering (RRS) spectral probe with strong RRS peak at 370 nm, the color changed to gray, and the RRS intensity decreased with the increase of fluorine ion concentration due to the RRS energy transfer (RRSET) from GO/NG to the complex. Under the selected condition, the decreased RRS peak ΔI370 nm was linear to fluorine ion concentration in the range of 6.0 × 10(-8)-1.3 × 10(-5)mol/L, with a detection limit of 3.0 × 10(-8)mol/L F(-). This RRSET method was applied to the analysis of fluorine in toothpaste and water samples, with satisfactory results. Copyright © 2015 Elsevier Ltd. All rights reserved.
Chen, X.; Park, J. J.
2012-12-01
The high uplift of the Tibet area is caused by the continental collision between the Indian plate and the Eurasian plate. The style of deformation along with the collision is still being debated, particularly whether the deformation is vertically coherent or not, i.e., whether the upper mantle deforms coherently with the crust. In this work, we have used quasi-Love (QL) waves to constrain the anisotropy pattern around the Tibet region. The existence of anisotropy gradients has been identified with the observations of QL waves, which is a converted Rayleigh-wave motion that follows the arrival of the Love wave. Further, the locations of the anisotropy gradients have been pinned with the delay time between the Love wave and the QL wave, which is determined from cross-correlation. Our results show that the frequency content of Tibetan QL wave is centered around 10 mHz, indicating the depth range of anisotropy should be in the asthenosphere. Most of the scatterers of QL wave that we can detect lie outside the Tibet Plateau. Their distribution correlates well with the boundary of the Persia-Tibet- Burma orogeny, which has been identified from surface geologic data. This correlation, between surface geology and upper mantle anisotropy inferred from QL observations at the orogenic boundary, suggests that the crust and upper mantle of the orogeny are deforming coherently. Other scatterers that are off the Persia-Tibet-Burma orogenic boundary mostly cluster in two locations, the Tarim Basin, and the Bangong-Nujiang Suture, where there could exist contrasting anisotropy patterns in the upper mantle. The deformation in the Tibet region is complicated, yet our research suggests a vertically coherent deformation style of the upper mantle in Tibet.
Dynamic coherent backscattering mirror
Energy Technology Data Exchange (ETDEWEB)
Zeylikovich, I.; Xu, M., E-mail: mxu@fairfield.edu [Physics Department, Fairfield University, Fairfield, CT 06824 (United States)
2016-02-15
The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation.
Wang, Menghua
2016-05-30
To understand and assess the effect of the sensor spectral response function (SRF) on the accuracy of the top of the atmosphere (TOA) Rayleigh-scattering radiance computation, new TOA Rayleigh radiance lookup tables (LUTs) over global oceans and inland waters have been generated. The new Rayleigh LUTs include spectral coverage of 335-2555 nm, all possible solar-sensor geometries, and surface wind speeds of 0-30 m/s. Using the new Rayleigh LUTs, the sensor SRF effect on the accuracy of the TOA Rayleigh radiance computation has been evaluated for spectral bands of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite and the Joint Polar Satellite System (JPSS)-1, showing some important uncertainties for VIIRS-SNPP particularly for large solar- and/or sensor-zenith angles as well as for large Rayleigh optical thicknesses (i.e., short wavelengths) and bands with broad spectral bandwidths. To accurately account for the sensor SRF effect, a new correction algorithm has been developed for VIIRS spectral bands, which improves the TOA Rayleigh radiance accuracy to ~0.01% even for the large solar-zenith angles of 70°-80°, compared with the error of ~0.7% without applying the correction for the VIIRS-SNPP 410 nm band. The same methodology that accounts for the sensor SRF effect on the Rayleigh radiance computation can be used for other satellite sensors. In addition, with the new Rayleigh LUTs, the effect of surface atmospheric pressure variation on the TOA Rayleigh radiance computation can be calculated precisely, and no specific atmospheric pressure correction algorithm is needed. There are some other important applications and advantages to using the new Rayleigh LUTs for satellite remote sensing, including an efficient and accurate TOA Rayleigh radiance computation for hyperspectral satellite remote sensing, detector-based TOA Rayleigh radiance computation, Rayleigh radiance calculations for high altitude
Bottom-type scattering layers and equatorial spread F
Directory of Open Access Journals (Sweden)
D. L. Hysell
2004-12-01
Full Text Available Jicamarca radar observations of bottom-type coherent scattering layers in the post-sunset bottomside F-region ionosphere are presented and analyzed. The morphology of the primary waves seen in radar images of the layers supports the hypothesis of kudeki+bhattacharyya-1999 that wind-driven gradient drift instabilities are operating. In one layer event when topside spread F did not occur, irregularities were distributed uniformly in space throughout the layers. In another event when topside spread F did eventually occur, the irregularities within the pre-existing bottom-type layers were horizontally clustered, with clusters separated by about 30km. The same horizontal periodicity was evident in the radar plumes and large-scale irregularities that emerged later in the event. We surmise that horizontal periodicity in bottom-type layer irregularity distribution is indicative of large-scale horizontal waves in the bottomside F-region that may serve as seed waves for large-scale Rayleigh Taylor instabilities. Key words. Ionosphere (equatorial ionosphere; ionospheric irregularties; plasma waves and instabilities
Ouyang, Huixiang; Liang, Aihui; Jiang, Zhiliang
2018-02-01
The stable Cu2O nanocubic (Cu2ONC) sol was prepared, based on graphene oxide (GO) catalysis of glucose-Fehling's reagent reaction, and its absorption and resonance Rayleigh scattering (RRS) spectra, transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were examined. Using the as-prepared Cu2ONC as RRS probe, and coupling with the neomycin sulfate (NEO) complex reaction, a new, simple, sensitive and selective RRS-energy transfer (RRS-ET) method was established for detection of neomycin sulfate, with a linear range of 1.4-112 μM and a detection limit of 0.4 μM. The method has been applied to the detection of neomycin sulfate in samples with satisfactory results.
Thomson scattering on non-equilibrium low density plasmas : principles, practice and challenges
Carbone, E.A.D.; Nijdam, S.
2015-01-01
In this paper, we review the main challenges related to laser Thomson scattering on low temperature plasmas. The main features of the triple grating spectrometer used to discriminate Thomson and Raman scattering signals from Rayleigh scattering and stray light are presented. The main parameters
Polarization Sensitive Coherent Raman Measurements of DCVJ
Anderson, Josiah; Cooper, Nathan; Lawhead, Carlos; Shiver, Tegan; Ujj, Laszlo
2014-03-01
Coherent Raman spectroscopy which recently developed into coherent Raman microscopy has been used to produce label free imaging of thin layers of material and find the spatial distributions of certain chemicals within samples, e.g. cancer cells.(1) Not all aspects of coherent scattering have been used for imaging. Among those for example are special polarization sensitive measurements. Therefore we have investigated the properties of polarization sensitive CARS spectra of a highly fluorescent molecule, DCVJ.(2) Spectra has been recorded by using parallel polarized and perpendicular polarized excitations. A special polarization arrangement was developed to suppress the non-resonant background scattering from the sample. These results can be used to improve the imaging properties of a coherent Raman microscope in the future. This is the first time coherent Raman polarization sensitive measurements have been used to characterize the vibrational modes of DCVJ. 1: K. I. Gutkowski, et al., ``Fluorescence of dicyanovinyl julolidine in a room temperature ionic liquid '' Chemical Physics Letters 426 (2006) 329 - 333 2: Fouad El-Diasty, ``Coherent anti-Stokes Raman scattering: Spectroscopy and microscopy'' Vibrational Spectroscopy 55 (2011) 1-37
Gessel, van A.F.H.; Carbone, E.A.D.; Bruggeman, P.J.; Mullen, van der J.J.A.M.
2012-01-01
Laser scattering provides a very direct method for measuring the local densities and temperatures inside a plasma. We present new experimental results of laser scattering on an argon atmospheric pressure microwave plasma jet operating in an air environment. The plasma is very small so a high spatial
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.
Wang, Yaqiong; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli
2013-03-01
In 0.1 mol L-1 HCl medium, antiemetic drugs (ATM), such as granisetron hydrochloride (GS) and tropisetron hydrochloride (TS), reacted with H3PW12O40·nH2O and formed 3:1 ion-association complex of [(ATM)3PW12O40], then self-aggregated into nanoparticles-[(ATM)3PW12O40]n with an average size of 100 nm. The reaction resulted in the enhancement of resonance Rayleigh scattering (RRS) and the absorption spectra. The increments of scattering intensity (ΔIRRS) and the change of absorbance (ΔA) were both directly proportional to the concentrations of ATM in certain ranges. Accordingly, two new RRS and spectrophotometric methods were proposed for ATM detection. The detection limits (3σ) of GS and TS were 3.2 ng mL-1 and 4.0 ng mL-1(RRS method), 112.5 ng mL-1 and 100.0 ng mL-1(spectrophotometric method). These two methods were applied to determine GS in orally disintegrating tablets and the results were in good agreement with the official method. The ground-state geometries and electronic structures of GS and TS were optimized by the hybrid density functional theory (DFT) method and the shape of [(ATM)3PW12O40]n was characterized by atomic force microscopy (AFM). Take the RRS method with higher sensitivity as an example, the reaction mechanism and the reasons for enhancement of scattering were discussed.
DEFF Research Database (Denmark)
Thrane, Lars; Frosz, Michael Henoch; Tycho, Andreas
2004-01-01
A recently developed analytical optical coherence tomography (OCT) model [Thrane et al., J. Opt. Soc. Am. A 17, 484 (2000)] allows the extraction of optical scattering parameters from OCT images, thereby permitting attenuation compensation in those images. By expanding this theoretical model, we...... have developed a new method for extracting optical scattering parameters from multilayered tissue structures in vivo. To verify this, we used a Monte Carlo (MC) OCT model as a numerical phantom to simulate the OCT signal for het-erogeneous multilayered tissue. Excellent agreement between the extracted......, and the results hold promise for expanding the functional imaging capabilities of OCT....
Maksimenko, V. V.; Zagaynov, V. A.; Agranovski, I. E.
2013-11-01
It is shown that complexities in a problem of elastic scattering of a photon on a pair of Rayleigh particles (two small metallic spheres) are similar to the complexities of the classic problem of three bodies in celestial mechanics. In the latter problem, as is well known, the phase trajectory of a system becomes a nonanalytical function of its variables. In our problem, the trajectory of a virtual photon at some frequency could be considered such as the well-known Antoine set (Antoine's necklace) or a chain with interlaced sections having zero topological dimension and fractal structure. Such a virtual “zero-dimensional” photon could be localized between the particles of the pair. The topology suppresses the photon's exit to the real world with dimensional equal-to-or-greater-than units. The physical reason for this type of photon localization is related to the “mechanical rigidity” of interlaced sections of the photon trajectory due to a singularity of energy density along these sections. Within the approximations used in this paper, the effect is possible if the frequency of the incident radiation is equal to double the frequency of the dipole surface plasmon in an isolated particle, which is the only character frequency in the problem. This condition and transformation of the photon trajectory to the zero-dimensional Antoine set reminds of some of the simplest variants of Poincaré's catastrophe in the dynamics of some nonintegrable systems. The influence of the localization on elastic light scattering by the pair is investigated.
International Nuclear Information System (INIS)
Metzler, N.; Velikovich, A.L.; Schmitt, A.J.; Karasik, M.; Serlin, V.; Mostovych, A.N.; Obenschain, S.P.; Gardner, J.H.; Aglitskiy, Y.
2003-01-01
A substantial reduction of the laser imprint with a short, low-energy 'shaping' laser pulse incident upon a foam-plastic sandwich target prior to the main laser pulse has been demonstrated to be possible [Metzler et al., Phys. Plasmas 9, 5050 (2002)]. Nonuniformity of this shaping pulse, however, produces standing sonic waves in the target. Laser-imprinted seeds for the Rayleigh-Taylor (RT) instability growth then emerge from the interaction of these waves with the strong shock wave launched by the drive laser pulse. Such coherent interaction between different waves and modes perturbed at the same wavelength is shown to be important in a variety of situations relevant to the inertial confinement fusion studies. As an example, an oscillatory transition from the classical Richtmyer-Meshkov shock-interface instability development to the RT growth exhibiting a characteristic phase reversal in a target of finite thickness is described. Another example refers to the feedout mechanism of seeding the perturbations that come from the nonuniformities of the rear (inner) surface of the laser target. The coherent interaction between the strong shock wave from the main laser pulse and the rippled rarefaction wave produced by a low-intensity foot of the pulse produces observable effects, such as an extra phase reversal compared to the case of no foot. Some of these predictions are shown to be consistent with our new experimental results obtained in the feedout geometry on the Nike laser facility [S. P. Obenschain et al. Phys. Plasmas 3, 2098 (1996)
Scattered X-ray beam nondestructive testing
International Nuclear Information System (INIS)
Harding, G.; Kosanetzky, J.
1988-01-01
X-ray scatter interactions generally dominate the linear attenuation coefficient at the photon energies typical of medical and industrial radiography. Specific advantages of X-ray scatter imaging, including a flexible choice of measurement geometry, direct 3D-imaging capability (tomography) and improved information for material characterization, are illustrated with results from Compton and coherent scatter devices. Applications of a Compton backscatter scanner (ComScan) in the aerospace industry and coherent scatter imaging in security screening are briefly considered [pt
Energy Technology Data Exchange (ETDEWEB)
Ghammraoui, B; M Popescu, L; Badano, A [Food & Drug Administration, Silver Spring, MD (United States)
2016-06-15
Purpose: To investigate the ability of Coherent Scatter Computed Tomography (CSCT) to distinguish non-invasively between type I calcifications, consisting of calcium oxalate dihydrate (CO) compounds which are more often associated with benign lesions, and type II calcifications containing hydroxyapatite (HA) which are predominantly associated with malignant tumors. Methods: The coherent scatter cross sections of HA and CO were measured using an energy dispersive x-ray diffractometer. The measured cross sections were introduced into MC-GPU Monte Carlo simulation code for studying the applicability of CSCT to discriminate between the two types of microcalcifications within the whole breast. Simulations were performed on a virtual phantom with inserted HA and CO spots of different sizes and placed in regions of interest having different background compositions. We considered a polychromatic x-ray source and an energy resolving photon counting detector. We applied an algorithm that estimates scatter components in projection space in order to obtain material-specific images of the breast. As material components adipose, glandular, HA and CO were used. The relative contrast of HA and CO components were used for type I and type II microcalcification discrimination. Results: The reconstructed CSCT images showed material-specific component-contrast values, with the highest CO or HA component contrast corresponding generally to the actual CO or HA feature, respectively. The discrimination performance varies with the x-ray intensity, calcification size, and background composition. The results were summarized using receiver operating characteristic (ROC) analysis with the area under the curve (AUC) taken as an overall indicator of discrimination performance and showing high AUC values up to unity. Conclusion: The simulation results obtained for a uniform breast imaging phantom indicate that CSCT has potential to be used as a non-invasive method for discrimination between type
Label-free cellular imaging by broadband coherent anti-Stokes Raman scattering microscopy.
Parekh, Sapun H; Lee, Young Jong; Aamer, Khaled A; Cicerone, Marcus T
2010-10-20
Raman microspectroscopy can provide the chemical contrast needed to characterize the complex intracellular environment and macromolecular organization in cells without exogenous labels. It has shown a remarkable ability to detect chemical changes underlying cell differentiation and pathology-related chemical changes in tissues but has not been widely adopted for imaging, largely due to low signal levels. Broadband coherent anti-Stokes Raman scattering (B-CARS) offers the same inherent chemical contrast as spontaneous Raman but with increased acquisition rates. To date, however, only spectrally resolved signals from the strong CH-related vibrations have been used for CARS imaging. Here, we obtain Raman spectral images of single cells with a spectral range of 600-3200 cm⁻¹, including signatures from weakly scattering modes as well as CH vibrations. We also show that B-CARS imaging can be used to measure spectral signatures of individual cells at least fivefold faster than spontaneous Raman microspectroscopy and can be used to generate maps of biochemical species in cells. This improved spectral range and signal intensity opens the door for more widespread use of vibrational spectroscopic imaging in biology and clinical diagnostics. Copyright © 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.
A simple proposal for Rayleigh's scaterring experiment
Directory of Open Access Journals (Sweden)
Adriano José Ortiz
2010-03-01
Full Text Available This work presents an alternative proposal for Rayleigh's scattering experiment presented and discussed in Krapas and Santos (2002 in this journal. Besides being simple and low-cost, the proposal suggested here is also proposing to demonstrate experimentally other physical phenomena such as polarization of light from the sky, the rainbow and reflection on non-conductive surfaces, as well as determine the direction of these biases. The polarization will be observed with the aid of Polaroid obtained from liquid crystal displays taken from damaged electronic devices and the Polaroid polarization direction will be established by the observation of Brewester's angle in reflection experiment.
Inelastic light scattering in crystals
Sushchinskii, M. M.
The papers presented in this volume are concerned with a variety of problems in optics and solid state physics, such as Raman scattering of light in crystals and disperse media, Rayleigh and inelastic scattering during phase transitions, characteristics of ferroelectrics in relation to the general soft mode concept, and inelastic spectral opalescence. A group-theory approach is used to classify the vibrational spectra of the crystal lattice and to analyze the properties of idealized crystal models. Particular attention is given to surface vibrational states and to the study of the surface layers of crystals and films by light scattering methods.
Sox, L.; Wickwar, V. B.; Fish, C. S.; Herron, J. P.
2014-12-01
Mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions. However, observations of these anomalies at midlatitudes are sparse. The very dense 11-year data set, collected between 1993-2004, with the Rayleigh-scatter lidar at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) at the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), has been carefully examined for such anomalies. The temperatures derived from these data extend over the mesosphere, from 45 to 90 km. During this period extensive data were acquired during seven major SSW events. In this work we aim to determine the characteristics of the midlatitude mesospheric temperatures during these seven major SSWs. To do this, comparisons were made between the temperature profiles on individual nights before, during, and after the SSW events and the corresponding derived climatological temperature profiles (31-day by 11-year average) for those nights. A consistent disturbance pattern was observed in the mesospheric temperatures during these SSWs. A distinct shift from the nominal winter temperature pattern to a pattern more characteristic of summer temperatures was seen in the midlatitude mesosphere close to when the zonal winds in the polar stratosphere (at 10 hPa, 60° N) reversed from eastward to westward. This shift lasted for several days. This change in pattern included coolings in the upper mesosphere, comparable to those seen in the polar regions, and warmings in the lower mesosphere.
Monitoring agrochemical diffusion through cuticle wax with coherent Raman scattering
Gaunt, Nicholas P.; Thomson, Niall; Padia, Faheem; Moger, Julian
2018-02-01
The world's population is increasing rapidly and higher calorific diets are becoming more common; as a consequence the demand for grain is predicted to increase by more than 50% by 2050 without a significant increase in the available agricultural land. Maximising the productivity of the existing agricultural land is key to maintaining food security and agrochemicals continue to be a key enabler for the efficiency gains required. However, agrochemicals can be susceptible to significant losses and thus often require further chemical to be applied to compensate. Sources of such losses include spray drift, poor spray retention/capture by the target and poor penetration through the plant cuticle. Adjuvants can be used to help mitigate such losses but characterising how they alter the movement of the active ingredients (AIs) can be challenging. In this contribution we demonstrate the use of coherent Raman Scattering (CRS) as a tool to enable in-situ, real-time, label free characterisation of agrochemical AI as they move through wax.
Status of the search of coherent neutrino nucleus elastic scattering at KSNL
Sharma, V.; Singh, V.; Subrahmanyam, V. S.; Wong, H. T.
2018-04-01
Status of search of coherent elastic neutrino-nucleus scattering (CEνNS) for reactor neutrino flux at Kuo-Sheng nuclear laboratory is discussed. Different detector candidates being used for CEνNS detection across the globe while Germanium detector with its well matured technology and sub-keV threshold, seem to open unseen experimental approach to CEνNS is widely discussed. Reactor neutrinos having energy below 10 MeV are ideal source for the study of CEνNS interaction. We studied about the possible CEνNS signals with associated uncertainties and limit on percentage of channeled nuclei in germanium crystal is quoted. Detection of flavourless CEνNS interaction can play a key role to open the new window on understanding of some unknown processes of the nature.
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.
Robles, Francisco E; Fischer, Martin C; Warren, Warren S
2016-01-11
Stimulated Raman scattering (SRS) enables fast, high resolution imaging of chemical constituents important to biological structures and functional processes, both in a label-free manner and using exogenous biomarkers. While this technology has shown remarkable potential, it is currently limited to point scanning and can only probe a few Raman bands at a time (most often, only one). In this work we take a fundamentally different approach to detecting the small nonlinear signals based on dispersion effects that accompany the loss/gain processes in SRS. In this proof of concept, we demonstrate that the dispersive measurements are more robust to noise compared to amplitude-based measurements, which then permit spectral or spatial multiplexing (potentially both, simultaneously). Finally, we illustrate how this method may enable different strategies for biochemical imaging using phase microscopy and optical coherence tomography.
Energy Technology Data Exchange (ETDEWEB)
Albanese, K; Morris, R; Spencer, J [Medical Physics Graduate Program, Duke University, Durham, NC (United States); Greenberg, J [Dept. of Electrical and Computer Engineering, Duke University, Durham, NC (United States); Kapadia, A [Carl E Ravin Advanced Imaging Laboratories, Durham, NC (United States)
2016-06-15
Purpose: Previously we reported the development of anthropomorphic tissue-equivalent scatter phantoms of the human breast. Here we present the first results from the scatter imaging of the tissue equivalent breast phantoms for breast cancer diagnosis. Methods: A breast phantom was designed to assess the capability of coded aperture coherent x-ray scatter imaging to classify different types of breast tissue (adipose, fibroglandular, tumor). The phantom geometry was obtained from a prone breast geometry scanned on a dedicated breast CT system. The phantom was 3D printed using the segmented DICOM breast CT data. The 3D breast phantom was filled with lard (as a surrogate for adipose tissue) and scanned in different geometries alongside excised human breast tissues (obtained from lumpectomy and mastectomy procedures). The raw data were reconstructed using a model-based reconstruction algorithm and yielded the location and form factor (i.e., momentum transfer (q) spectrum) of the materials that were imaged. The measured material form factors were then compared to the ground truth measurements acquired by x-ray diffraction (XRD) imaging. Results: Our scatter imaging system was able to define the location and composition of the various materials and tissues within the phantom. Cancerous breast tissue was detected and classified through automated spectral matching and an 86% correlation threshold. The total scan time for the sample was approximately 10 minutes and approaches workflow times for clinical use in intra-operative or other diagnostic tasks. Conclusion: This work demonstrates the first results from an anthropomorphic tissue equivalent scatter phantom to characterize a coherent scatter imaging system. The functionality of the system shows promise in applications such as intra-operative margin detection or virtual biopsy in the diagnosis of breast cancer. Future work includes using additional patient-derived tissues (e.g., human fat), and modeling additional organs
Würthwein, Thomas; Brinkmann, Maximilian; Hellwig, Tim; Fallnich, Carsten
2017-11-21
We present the simultaneous detection of the spectrum and the complete polarization state of a multiplex coherent anti-Stokes Raman scattering signal with a fast division-of-amplitude spectro-polarimeter. The spectro-polarimeter is based on a commercial imaging spectrograph, a birefringent wedge prism, and a segmented polarizer. Compared to the standard rotating-retarder fixed-analyzer spectro-polarimeter, only a single measurement is required and an up to 21-fold reduced acquisition time is shown. The measured Stokes parameters allow us to differentiate between vibrational symmetries and to determine the depolarization ratio ρ by data post-processing.
Neutron Brillouin scattering in dense fluids
Energy Technology Data Exchange (ETDEWEB)
Verkerk, P [Technische Univ. Delft (Netherlands); FINGO Collaboration
1997-04-01
Thermal neutron scattering is a typical microscopic probe for investigating dynamics and structure in condensed matter. In contrast, light (Brillouin) scattering with its three orders of magnitude larger wavelength is a typical macroscopic probe. In a series of experiments using the improved small-angle facility of IN5 a significant step forward is made towards reducing the gap between the two. For the first time the transition from the conventional single line in the neutron spectrum scattered by a fluid to the Rayleigh-Brillouin triplet known from light-scattering experiments is clearly and unambiguously observed in the raw neutron data without applying any corrections. Results of these experiments are presented. (author).
Linear attenuation coefficients of tissues from 1 keV to 150 keV
Böke, Aysun
2014-09-01
The linear attenuation coefficients and three interaction processes have been computed for liver, kidney, muscle, fat and for a range of x-ray energies from 1 keV to 150 keV. Molecular photoelectric absorption cross sections were calculated from atomic cross section data. Total coherent (Rayleigh) and incoherent (Compton) scattering cross sections were obtained by numerical integration over combinations of F2m(x) with the Thomson formula and Sm(x) with the Klein-Nishina formula, respectively. For the coherent (Rayleigh) scattering cross section calculations, molecular form factors were obtained from recent experimental data in the literature for values of xelements involved in tissue composition is 5 for liver, 47 for kidney, 44 for muscle and 3 for fat. The results are compared with previously published experimental and theoretical linear attenuation coefficients. In general, good agreement is obtained. The molecular form factors and scattering functions and cross sections are incorporated into a Monte Carlo program. The energy distributions of x-ray photons scattered from tissues have been simulated and the results are presented.
Thomson scattering measurements on an atmospheric Ar dc discharge lamp
Zhu, Xiao-Yan; Redwitz, M.; Kieft, E.R.; Sande, van de M.J.; Mullen, van der J.J.A.M.
2004-01-01
Thomson scattering (TS) experiments have been performed in the region near the electrodes of a dc powered model lamp filled with 1-2 bar argon gas. In order to suppress the false stray light and Rayleigh scattered photons, a triple grating spectrograph was used. In this way the electron density and
DEFF Research Database (Denmark)
Iles-Smith, Jake; McCutcheon, Dara; Mørk, Jesper
2016-01-01
a substantial suppression of detrimental interactions between the source and its phonon environment. Nevertheless, we demonstrate here that this reasoning is incomplete, and phonon interactions continue to play a crucial role in determining solid-state emission characteristics even for very weak excitation. We...... find that the sideband resulting from non-Markovian relaxation of the phonon environment leads to a fundamental limit to the fraction of coherently scattered light and to the visibility of two-photon coalescence at weak driving, both of which are absent for atomic systems or within simpler Markovian...
Coherent light scattering by nuclear etched tracks in the PADC (a form of CR-39)
Energy Technology Data Exchange (ETDEWEB)
Groetz, J.E.; Chambaudet, A. [Universite de Franche-Comte, Besancon (France). Lab. de Microanalyses Nucleaires; Lacourt, A. [Laboratoire d`Optique P.M. Duffieux, UMR 6603 CNRS, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France)
1998-08-01
A new kind of measurement has been proposed to improve the reading of the solid state nuclear track detector CR-39. This method is based on coherent light scattering (He-Ne laser) by etched proton tracks, and is complementary to observation under an optical microscope and reading by optical density of the CR-39. The irradiated and chemically etched CR-39 sample is illuminated by a laser beam under a normal incidence angle. The light intensity diffracted by the tracks beyond the sample - defined with the bi-directional transmissive distribution functions - is measured with a photodiode. Thus, the bi-directional transmissive distribution functions depend on the characteristics of the irradiation, namely the track density, track sizes and orientations. We have performed a track light diffraction model calculation through the use of the Fraunhofer diffraction, Babinet`s principle and the spatial coherence and incoherence. We compared calculations and experimental results for the different shapes of tracks: conical, oblique and spherical-shaped. (orig.) 14 refs.
Coherent light scattering by nuclear etched tracks in the PADC (a form of CR-39)
International Nuclear Information System (INIS)
Groetz, J.E.; Chambaudet, A.
1998-01-01
A new kind of measurement has been proposed to improve the reading of the solid state nuclear track detector CR-39. This method is based on coherent light scattering (He-Ne laser) by etched proton tracks, and is complementary to observation under an optical microscope and reading by optical density of the CR-39. The irradiated and chemically etched CR-39 sample is illuminated by a laser beam under a normal incidence angle. The light intensity diffracted by the tracks beyond the sample - defined with the bi-directional transmissive distribution functions - is measured with a photodiode. Thus, the bi-directional transmissive distribution functions depend on the characteristics of the irradiation, namely the track density, track sizes and orientations. We have performed a track light diffraction model calculation through the use of the Fraunhofer diffraction, Babinet's principle and the spatial coherence and incoherence. We compared calculations and experimental results for the different shapes of tracks: conical, oblique and spherical-shaped. (orig.)
International Nuclear Information System (INIS)
Grech, M.; Riazuelo, G.; Pesme, D.; Weber, S.; Tikhonchuk, V. T.
2009-01-01
A statistical model for forward stimulated-Brillouin scattering is developed for a spatially incoherent, monochromatic, laser beam propagating in a plasma. The threshold above which the laser beam spatial incoherence cannot prevent the coherent growth of forward stimulated-Brillouin scattering is computed. It is found to be well below the threshold for self-focusing. Three-dimensional simulations confirm its existence and reveal the onset of beam spray above it. From these results, we propose a new figure of merit for the control of propagation through a plasma of a spatially incoherent laser beam
Optical Coherence and Quantum Optics
Mandel, Leonard
1995-01-01
This book presents a systematic account of optical coherence theory within the framework of classical optics, as applied to such topics as radiation from sources of different states of coherence, foundations of radiometry, effects of source coherence on the spectra of radiated fields, coherence theory of laser modes, and scattering of partially coherent light by random media. The book starts with a full mathematical introduction to the subject area and each chapter concludes with a set of exercises. The authors are renowned scientists and have made substantial contributions to many of the topi
Smetanin, I. V.; Erokhin, A. I.; Baranov, A. N.
2018-07-01
We report the results of the experimental and theoretical study of stimulated temperature scattering in toluene and hexane solutions of Ag-nanoparticles, as well as in pure toluene in the two-photon absorption regime. A four-wave mixing scheme with two counter-propagating pump waves of the same frequency is utilised to demonstrate the lasing effect and the amplification of the backscattered anti-Stokes signal. For the first time, we have measured anti-Stokes spectral shifts which turn out to appreciably exceed the Rayleigh line widths in those liquids. It is shown that the amplification effect is provided predominantly by thermally induced coherent polarisation oscillations, while the dynamic interference temperature grating causes the formation of a self-induced optical cavity inside the interaction region.
International workshop on phase retrieval and coherent scattering. Coherence 2005
International Nuclear Information System (INIS)
Nugent, K.A.; Fienup, J.R.; Van Dyck, D.; Van Aert, S.; Weitkamp, T.; Diaz, A.; Pfeiffer, F.; Cloetens, P.; Stampanoni, M.; Bunk, O.; David, C.; Bronnikov, A.V.; Shen, Q.; Xiao, X.; Gureyev, T.E.; Nesterets, Ya.I.; Paganin, D.M.; Wilkins, S.W.; Mokso, R.; Cloetens, P.; Ludwig, W.; Hignette, O.; Maire, E.; Faulkner, H.M.L.; Rodenburg, J.M.; Wu, X.; Liu, H.; Grubel, G.; Ludwig, K.F.; Livet, F.; Bley, F.; Simon, J.P.; Caudron, R.; Le Bolloc'h, D.; Moussaid, A.; Gutt, C.; Sprung, M.; Madsen, A.; Tolan, M.; Sinha, S.K.; Scheffold, F.; Schurtenberger, P.; Robert, A.; Madsen, A.; Falus, P.; Borthwick, M.A.; Mochrie, S.G.J.; Livet, F.; Sutton, M.D.; Ehrburger-Dolle, F.; Bley, F.; Geissler, E.; Sikharulidze, I.; Jeu, W.H. de; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Naryanan, S.; Sinha, S.K.; Lal, J.; Naryanan, S.; Sinha, S.K.; Lal, J.; Robinson, I.K.; Chapman, H.N.; Barty, A.; Beetz, T.; Cui, C.; Hajdu, J.; Hau-Riege, S.P.; He, H.; Stadler, L.M.; Sepiol, B.; Harder, R.; Robinson, I.K.; Zontone, F.; Vogl, G.; Howells, M.; London, R.; Marchesini, S.; Shapiro, D.; Spence, J.C.H.; Weierstall, U.; Eisebitt, S.; Shapiro, D.; Lima, E.; Elser, V.; Howells, M.R.; Huang, X.; Jacobsen, C.; Kirz, J.; Miao, H.; Neiman, A.; Sayre, D.; Thibault, P.; Vartanyants, I.A.; Robinson, I.K.; Onken, J.D.; Pfeifer, M.A.; Williams, G.J.; Pfeiffer, F.; Metzger, H.; Zhong, Z.; Bauer, G.; Nishino, Y.; Miao, J.; Kohmura, Y.; Yamamoto, M.; Takahashi, Y.; Koike, K.; Ebisuzaki, T.; Ishikawa, T.; Spence, J.C.H.; Doak, B.
2005-01-01
The contributions of the participants have been organized into 3 topics: 1) phase retrieval methods, 2) X-ray photon correlation spectroscopy, and 3) coherent diffraction imaging. This document gathers the abstracts of the presentations and of the posters
International workshop on phase retrieval and coherent scattering. Coherence 2005
Energy Technology Data Exchange (ETDEWEB)
Nugent, K.A.; Fienup, J.R.; Van Dyck, D.; Van Aert, S.; Weitkamp, T.; Diaz, A.; Pfeiffer, F.; Cloetens, P.; Stampanoni, M.; Bunk, O.; David, C.; Bronnikov, A.V.; Shen, Q.; Xiao, X.; Gureyev, T.E.; Nesterets, Ya.I.; Paganin, D.M.; Wilkins, S.W.; Mokso, R.; Cloetens, P.; Ludwig, W.; Hignette, O.; Maire, E.; Faulkner, H.M.L.; Rodenburg, J.M.; Wu, X.; Liu, H.; Grubel, G.; Ludwig, K.F.; Livet, F.; Bley, F.; Simon, J.P.; Caudron, R.; Le Bolloc' h, D.; Moussaid, A.; Gutt, C.; Sprung, M.; Madsen, A.; Tolan, M.; Sinha, S.K.; Scheffold, F.; Schurtenberger, P.; Robert, A.; Madsen, A.; Falus, P.; Borthwick, M.A.; Mochrie, S.G.J.; Livet, F.; Sutton, M.D.; Ehrburger-Dolle, F.; Bley, F.; Geissler, E.; Sikharulidze, I.; Jeu, W.H. de; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Naryanan, S.; Sinha, S.K.; Lal, J.; Naryanan, S.; Sinha, S.K.; Lal, J.; Robinson, I.K.; Chapman, H.N.; Barty, A.; Beetz, T.; Cui, C.; Hajdu, J.; Hau-Riege, S.P.; He, H.; Stadler, L.M.; Sepiol, B.; Harder, R.; Robinson, I.K.; Zontone, F.; Vogl, G.; Howells, M.; London, R.; Marchesini, S.; Shapiro, D.; Spence, J.C.H.; Weierstall, U.; Eisebitt, S.; Shapiro, D.; Lima, E.; Elser, V.; Howells, M.R.; Huang, X.; Jacobsen, C.; Kirz, J.; Miao, H.; Neiman, A.; Sayre, D.; Thibault, P.; Vartanyants, I.A.; Robinson, I.K.; Onken, J.D.; Pfeifer, M.A.; Williams, G.J.; Pfeiffer, F.; Metzger, H.; Zhong, Z.; Bauer, G.; Nishino, Y.; Miao, J.; Kohmura, Y.; Yamamoto, M.; Takahashi, Y.; Koike, K.; Ebisuzaki, T.; Ishikawa, T.; Spence, J.C.H.; Doak, B
2005-07-01
The contributions of the participants have been organized into 3 topics: 1) phase retrieval methods, 2) X-ray photon correlation spectroscopy, and 3) coherent diffraction imaging. This document gathers the abstracts of the presentations and of the posters.
Directory of Open Access Journals (Sweden)
Bo-Ram Lee
Full Text Available We performed dye-enhanced imaging of mouse brain microvessels using spectral focusing coherent anti-Stokes Raman scattering (SF-CARS microscopy. The resonant signals from C-H stretching in forward CARS usually show high background intensity in tissues, which makes CARS imaging of microvessels difficult. In this study, epi-detection of back-scattered SF-CARS signals showed a negligible background, but the overall intensity of resonant CARS signals was too low to observe the network of brain microvessels. Therefore, Evans blue (EB dye was used as contrasting agent to enhance the back-scattered SF-CARS signals. Breakdown of brain microvessels by inducing hemorrhage in a mouse was clearly visualized using backward SF-CARS signals, following intravenous injection of EB. The improved visualization of brain microvessels with EB enhanced the sensitivity of SF-CARS, detecting not only the blood vessels themselves but their integrity as well in the brain vasculature.
Elastic scattering of low energy γ-rays
International Nuclear Information System (INIS)
Whittingham, I.B.
1978-05-01
Theoretical cross sections for the elastic scattering of 245, 334, 444, 779, 1086, 1112 and 1408 keV γ-rays by Pb are obtained for scattering angles up to 150 degrees. Three sets of Rayleigh scattering amplitudes have been computed using (1) the calculations of Johnson and Cheng, (2) the K shell calculations of Brown and co-workers supplemented by form factors amplitudes for higher shells, and (3) form factor amplitudes for all shells. Nuclear Thomson amplitudes have been included for all energies and, for 1408 keV, Delbruck scattering based upon the calculations of Papatzacos and Mork has been included. Nuclear resonance scattering is show to be negligble for all energies
Energy Technology Data Exchange (ETDEWEB)
Strauss, R.; Rothe, J.; Angloher, G.; Hauff, D.; Mancuso, M.; Petricca, F.; Proebst, F.; Seidel, W.; Stodolsky, L. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Bento, A. [Universidade de Coimbra, CIUC, Departamento de Fisica, Coimbra (Portugal); Guetlein, A.; Kluck, H.; Schieck, J. [Institut fuer Hochenergiephysik, Oesterreichische Akademie der Wissenschaften, Vienna (Austria); Vienna University of Technology, Atominstitut, Vienna (Austria); Oberauer, L.; Schoenert, S. [Technische Universitaet Muenchen, Physik-Department, Garching (Germany)
2017-08-15
We discuss a small-scale experiment, called ν-cleus, for the first detection of coherent neutrino-nucleus scattering by probing nuclear-recoil energies down to the 10 eV regime. The detector consists of low-threshold CaWO{sub 4} and Al{sub 2}O{sub 3} calorimeter arrays with a total mass of about 10 g and several cryogenic veto detectors operated at millikelvin temperatures. Realizing a fiducial volume and a multi-element target, the detector enables active discrimination of γ, neutron and surface backgrounds. A first prototype Al{sub 2}O{sub 3} device, operated above ground in a setup without shielding, has achieved an energy threshold of ∝20 eV and further improvements are in reach. A sensitivity study for the detection of coherent neutrino scattering at nuclear power plants shows a unique discovery potential (5 σ) within a measuring time of
Cézard, Nicolas; Dolfi-Bouteyre, Agnès; Huignard, Jean-Pierre; Flamant, Pierre H
2009-04-20
A new concept of spectrum analyzer is proposed for short-range lidar measurements in airborne applications. It implements a combination of two fringe-imaging Michelson interferometers to analyze the Rayleigh-Mie spectrum backscattered by molecules and particles at 355 nm. The objective is to perform simultaneous measurements of four variables: the air speed, the air temperature and density, and the particle scattering ratio. The Cramer-Rao bounds are calculated to evaluate the best expectable measurement accuracies. The performance optimization shows that a Michelson interferometer with a path difference of 3 cm is optimal for air speed measurements in clear air. To optimize density, temperature, and scattering ratio measurements, the second interferometer should be set to a path difference of 10 cm at least; 20 cm would be better to be less sensitive to the actual Rayleigh-Brillouin line shape.
Xia, Haiyun; Dou, Xiankang; Shangguan, Mingjia; Zhao, Ruocan; Sun, Dongsong; Wang, Chong; Qiu, Jiawei; Shu, Zhifeng; Xue, Xianghui; Han, Yuli; Han, Yan
2014-09-08
Temperature detection remains challenging in the low stratosphere, where the Rayleigh integration lidar is perturbed by aerosol contamination and ozone absorption while the rotational Raman lidar is suffered from its low scattering cross section. To correct the impacts of temperature on the Rayleigh Doppler lidar, a high spectral resolution lidar (HSRL) based on cavity scanning Fabry-Perot Interferometer (FPI) is developed. By considering the effect of the laser spectral width, Doppler broadening of the molecular backscatter, divergence of the light beam and mirror defects of the FPI, a well-behaved transmission function is proved to show the principle of HSRL in detail. Analysis of the statistical error of the HSRL is carried out in the data processing. A temperature lidar using both HSRL and Rayleigh integration techniques is incorporated into the Rayleigh Doppler wind lidar. Simultaneous wind and temperature detection is carried out based on the combined system at Delhi (37.371°N, 97.374°E; 2850 m above the sea level) in Qinghai province, China. Lower Stratosphere temperature has been measured using HSRL between 18 and 50 km with temporal resolution of 2000 seconds. The statistical error of the derived temperatures is between 0.2 and 9.2 K. The temperature profile retrieved from the HSRL and wind profile from the Rayleigh Doppler lidar show good agreement with the radiosonde data. Specifically, the max temperature deviation between the HSRL and radiosonde is 4.7 K from 18 km to 36 km, and it is 2.7 K between the HSRL and Rayleigh integration lidar from 27 km to 34 km.
DEFF Research Database (Denmark)
Hvam, Jørn Märcher; Langbein, Wolfgang; Borri, Paola
1999-01-01
Coherent optical spectroscopy in the form of nonlinear transient four-wave mixing (TFWM) and linear resonant Rayleigh scattering (RRS) has been applied to investigate the exciton dynamics of low-dimensional semiconductor heterostructures. The dephasing times of excitons are determined from...
Energy Technology Data Exchange (ETDEWEB)
Dong Lijun [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen Xingguo [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)]. E-mail: chenxg@lzu.edu.cn; Hu Zhide [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)
2007-05-15
The determination of proteins with 2-(4-chloro-2-phosphonophenylazo)-7-(4-iodophenylazo) -1,8-dihydroxynaphthalene-3,6-disulfonic acid (CPA-pI) by Rayleigh light scattering (RLS) was studied in this paper. The weak RLS of CPA-pI and BSA can be enhanced greatly by the addition of Al{sup 3+} at the pH 5.6 and an enhanced RLS signal was produced at 365-385 nm. Based on the reaction of CPA-pI, Al{sup 3+} and proteins, a new quantitative determination method for proteins has been developed. The effect of three variables for the determination of proteins was optimized by means of artificial neural networks (ANNs) using extended delta-bar-delta (EDBD) algorithms with the optimal network structure of 3-5-1. This method is very sensitive (2.5-35.4 {mu}g/ml for bovine serum albumin (BSA)), rapid (<2 min), simple (one step) and tolerance of most interfering substances. Six samples of protein in human serum were determined and the maximum relative error is no more than 2% and the recovery is between 95% and 105%.
Coherent deeply virtual Compton scattering off 3He and neutron generalized parton distributions
Directory of Open Access Journals (Sweden)
Rinaldi Matteo
2014-06-01
Full Text Available It has been recently proposed to study coherent deeply virtual Compton scattering (DVCS off 3He nuclei to access neutron generalized parton distributions (GPDs. In particular, it has been shown that, in Impulse Approximation (IA and at low momentum transfer, the sum of the quark helicity conserving GPDs of 3He, H and E, is dominated by the neutron contribution. This peculiar result makes the 3He target very promising to access the neutron information. We present here the IA calculation of the spin dependent GPD H See Formula in PDF of 3He. Also for this quantity the neutron contribution is found to be the dominant one, at low momentum transfer. The known forward limit of the IA calculation of H See Formula in PDF , yielding the polarized parton distributions of 3He, is correctly recovered. The extraction of the neutron information could be anyway non trivial, so that a procedure, able to take into account the nuclear effects encoded in the IA analysis, is proposed. These calculations, essential for the evaluation of the coherent DVCS cross section asymmetries, which depend on the GPDs H,E and H See Formula in PDF , represent a crucial step for planning possible experiments at Jefferson Lab.
Kang, Bin; Austin, Lauren A; El-Sayed, Mostafa A
2012-10-10
Due to their strong enhancement of scattered light, plasmonic nanoparticles have been utilized for various biological and medical applications. Here, we describe a new technique, Targeted Plasmonic-Enhanced Single-Cell Rayleigh/Raman Spectroscopy, to monitor the molecular changes of any cell-component, such as the nucleus, during the different phases of its full cell cycle by simultaneously recording its Rayleigh images and Raman vibration spectra in real-time. The analysis of the observed Raman DNA and protein peaks allowed the different phases of the cell cycle to be identified. This technique could be used for disease diagnostics and potentially improve our understanding of the molecular mechanisms of cellular functions such as division, death, signaling, and drug action.
Roessli, B.; Böni, P.
2000-01-01
The technique of polarized neutron scattering is reviewed with emphasis on applications. Many examples of the usefulness of the method in various fields of physics are given like the determination of spin density maps, measurement of complex magnetic structures with spherical neutron polarimetry, inelastic neutron scattering and separation of coherent and incoherent scattering with help of the generalized XYZ method.
Casini, R.; del Pino Alemán, T.; Manso Sainz, R.
2017-02-01
We discuss the implementation of physically meaningful branching ratios between the CRD and partial redistribution contributions to the emissivity of a polarized multi-term atom in the presence of both inelastic and elastic collisions. Our derivation is based on a recent theoretical formulation of partially coherent scattering, and it relies on a heuristic diagrammatic analysis of the various radiative and collisional processes to determine the proper form of the branching ratios. The expression we obtain for the emissivity is {\\boldsymbol{\\varepsilon }}=[{{\\boldsymbol{\\varepsilon }}}(1)-{{\\boldsymbol{\\varepsilon }}}{{f}.{{s}}.}(2)]+{{\\boldsymbol{\\varepsilon }}}(2), where {{\\boldsymbol{\\varepsilon }}}(1) and {{\\boldsymbol{\\varepsilon }}}(2) are the emissivity terms for the redistributed and partially coherent radiation, respectively, and where “f.s.” implies that the corresponding term must be evaluated assuming a flat-spectrum average of the incident radiation. This result is shown to be in agreement with prior literature on the subject in the limit of the unpolarized multi-level atom.
Casamayou-Boucau, Yannick; Ryder, Alan G.
2017-09-01
Anisotropy resolved multidimensional emission spectroscopy (ARMES) provides valuable insights into multi-fluorophore proteins (Groza et al 2015 Anal. Chim. Acta 886 133-42). Fluorescence anisotropy adds to the multidimensional fluorescence dataset information about the physical size of the fluorophores and/or the rigidity of the surrounding micro-environment. The first ARMES studies used standard thin film polarizers (TFP) that had negligible transmission between 250 and 290 nm, preventing accurate measurement of intrinsic protein fluorescence from tyrosine and tryptophan. Replacing TFP with pairs of broadband wire grid polarizers enabled standard fluorescence spectrometers to accurately measure anisotropies between 250 and 300 nm, which was validated with solutions of perylene in the UV and Erythrosin B and Phloxine B in the visible. In all cases, anisotropies were accurate to better than ±1% when compared to literature measurements made with Glan Thompson or TFP polarizers. Better dual wire grid polarizer UV transmittance and the use of excitation-emission matrix measurements for ARMES required complete Rayleigh scatter elimination. This was achieved by chemometric modelling rather than classical interpolation, which enabled the acquisition of pure anisotropy patterns over wider spectral ranges. In combination, these three improvements permit the accurate implementation of ARMES for studying intrinsic protein fluorescence.
Zhu, Jinghui; Qin, Mingyou; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli
2014-09-15
A flow injection analysis (FIA) system combined with dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) has been established and validated for rapid determination of malachite green (MG) and its metabolite in fish samples. Under experimental condition, MG would react with Erythrosin (Ery) to form ion-association complexes, resulting in the occurrence of two RRS peaks and a dramatic enhancement of RRS intensity. The maximum RRS peaks were located at 286 nm and 337 nm. It is noted that the increments of both of these two peaks were proportional to the concentration of MG. The detection limit of DWO-RRS was 1.5 ng/mL, which was comparable to several reported methods. Moreover, the results of real sample analysis exhibited an acceptable recovery between 97.5% and 103.6%, indicating that the method had good reproducibility. Copyright © 2014 Elsevier B.V. All rights reserved.
Development of Rayleigh Doppler lidar for measuring middle atmosphere winds
Raghunath, K.; Patra, A. K.; Narayana Rao, D.
Interpretation of most of the middle and upper atmospheric dynamical and chemical data relies on the climatological description of the wind field Rayleigh Doppler lidar is one instrument which monitors wind profiles continuously though continuity is limited to clear meteorological conditions in the middle atmosphere A Doppler wind lidar operating in incoherent mode gives excellent wind and temperature information at these altitudes with necessary spectral sensitivity It observes atmospheric winds by measuring the spectral shift of the scattered light due to the motions of atmospheric molecules with background winds and temperature by spectral broadening The presentation is about the design and development of Incoherent Doppler lidar to obtain wind information in the height regions of 30-65 km The paper analyses and describes various types of techniques that can be adopted viz Edge technique and Fringe Imaging technique The paper brings out the scientific objectives configuration simulations error sources and technical challenges involved in the development of Rayleigh Doppler lidar The presentation also gives a novel technique for calibrating the lidar
Rayleigh scattering in the atmospheres of hot stars
Czech Academy of Sciences Publication Activity Database
Fišák, J.; Krtička, J.; Munzar, D.; Kubát, Jiří
2016-01-01
Roč. 590, June (2016), A95/1-A95/6 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GA14-02385S Grant - others:GA MŠk(CZ) LM2010005 Institutional support: RVO:67985815 Keywords : atomic processes * scattering * stars: chemically peculiar Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014
Directory of Open Access Journals (Sweden)
Nicolas Pinel
2012-01-01
Full Text Available This paper studies the coherent scattering from random rough layers made up of two uncorrelated random rough surfaces, by considering 2D problems. The results from a rigorous electromagnetic method called PILE (propagation-inside-layer expansion are used as a reference. Also, two asymptotic analytical approaches are presented and compared to the numerical model for comparison. The cases of surfaces with both Gaussian and exponential correlations are studied. This approach is applied to road survey by GPR at nadir.
Directory of Open Access Journals (Sweden)
G. E. Bond
1997-11-01
Full Text Available Results are presented from an experimental campaign in April 1996, in which the new CUTLASS (Co-operative UK twin-located Auroral Sounding System coherent scatter radar was employed to observe artificial field aligned irregularities (FAI generated by the EISCAT (European Incoherent SCATter heating facility at Tromsø, Norway. The distribution of backscatter intensity from within the heated region has been investigated both in azimuth and range with the Finland component of CUTLASS, and the first observations of artificial irregularities by the Iceland radar are also presented. The heated region has been measured to extend over a horizontal distance of 170±50km, which by comparison with a model of the heater beam pattern corresponds to a threshold electric field for FAI of between 0.1 and 0.01V/m. Differences between field-aligned and vertical propagation heating are also presented.
Modelling of classical ghost images obtained using scattered light
International Nuclear Information System (INIS)
Crosby, S; Castelletto, S; Aruldoss, C; Scholten, R E; Roberts, A
2007-01-01
The images obtained in ghost imaging with pseudo-thermal light sources are highly dependent on the spatial coherence properties of the incident light. Pseudo-thermal light is often created by reducing the coherence length of a coherent source by passing it through a turbid mixture of scattering spheres. We describe a model for simulating ghost images obtained with such partially coherent light, using a wave-transport model to calculate the influence of the scattering on initially coherent light. The model is able to predict important properties of the pseudo-thermal source, such as the coherence length and the amplitude of the residual unscattered component of the light which influence the resolution and visibility of the final ghost image. We show that the residual ballistic component introduces an additional background in the reconstructed image, and the spatial resolution obtainable depends on the size of the scattering spheres
Modelling of classical ghost images obtained using scattered light
Energy Technology Data Exchange (ETDEWEB)
Crosby, S; Castelletto, S; Aruldoss, C; Scholten, R E; Roberts, A [School of Physics, University of Melbourne, Victoria, 3010 (Australia)
2007-08-15
The images obtained in ghost imaging with pseudo-thermal light sources are highly dependent on the spatial coherence properties of the incident light. Pseudo-thermal light is often created by reducing the coherence length of a coherent source by passing it through a turbid mixture of scattering spheres. We describe a model for simulating ghost images obtained with such partially coherent light, using a wave-transport model to calculate the influence of the scattering on initially coherent light. The model is able to predict important properties of the pseudo-thermal source, such as the coherence length and the amplitude of the residual unscattered component of the light which influence the resolution and visibility of the final ghost image. We show that the residual ballistic component introduces an additional background in the reconstructed image, and the spatial resolution obtainable depends on the size of the scattering spheres.
Introductory theory of neutron scattering
International Nuclear Information System (INIS)
Gunn, J.M.F.
1986-12-01
The paper comprises a set of six lecture notes which were delivered to the summer school on 'Neutron Scattering at a pulsed source', Rutherford Laboratory, United Kingdom, 1986. The lectures concern the physical principles of neutron scattering. The topics of the lectures include: diffraction, incoherent inelastic scattering, connection with the Schroedinger equation, magnetic scattering, coherent inelastic scattering, and surfaces and neutron optics. (UK)
Hermite scatterers in an ultraviolet sky
Parker, Kevin J.
2017-12-01
The scattering from spherical inhomogeneities has been a major historical topic in acoustics, optics, and electromagnetics and the phenomenon shapes our perception of the world including the blue sky. The long wavelength limit of ;Rayleigh scattering; is characterized by intensity proportional to k4 (or λ-4) where k is the wavenumber and λ is the wavelength. With the advance of nanotechnology, it is possible to produce scatterers that are inhomogeneous with material properties that are functions of radius r, such as concentric shells. We demonstrate that with proper choice of material properties linked to the Hermite polynomials in r, scatterers can have long wavelength scattering behavior of higher powers: k8, k16, and higher. These ;Hermite scatterers; could be useful in providing unique signatures (or colors) to regions where they are present. If suspended in air under white light, the back-scattered spectrum would be shifted from blue towards violet and then ultraviolet as the higher order Hermite scatterers were illuminated.
International Nuclear Information System (INIS)
Kong, L.; Liu, Z.; Hu, X.; Liu, S.; Li, W.
2012-01-01
The interaction of insulin with calf thymus deoxyribonucleic acid (ctDNA) leads to a complex that displays remarkably enhanced resonance Rayleigh scattering (RRS). The complex and its formation were investigated by atomic force microscopy and by absorption, fluorescence and circular dichroism spectroscopies. We show that the Tyr B16, Tyr B26 and Phe B24 amino acids near the active center (Phe B25) were influenced by the interaction, whereas Tyr A14, Tyr A19 and Phe B1 (which are located far away from the active center) were less influenced. The interaction provide a way in the quantitation of both ctDNA and insulin with high sensitivity. When ctDNA is used as a probe to quantify insulin, the detection limit (3σ) is 6.0 ng mL -1 . If, inversely, insulin is used as a probe to quantify ctDNA, the detection limit (3σ) is 7.2 ng mL -1 . The analysis of synthetic DNA samples and an insulin infection sample provided satisfactory results. (author)
Determination of X-ray anomalous scattering in silicon
International Nuclear Information System (INIS)
Cusatis, C.
1987-01-01
The linear attenuation coeficient for X-ray in silicon was measured with approximately 0,1% accuracy, for 6 diferent wavelenghts of caracteristic radiation. From these result the imaginary parts of the atomic scattering factors, for silicon and for those wavelenghts, were obtained with the same accuracy. The results are compared with the most recent published values. The proposed method to avoid Rayleigh scattering can be used for any type of ''perfect'' crystal. (author) [pt
Delbrueck scattering of monoenergetic photons
International Nuclear Information System (INIS)
Kahane, S.
1978-05-01
The Delbrueck effect was experimentally investigated in high Z nuclei with monoenergetic photons in the range 6.8-11.4 MeV. Two different methods were used for measurements of the differential scattering cross-section, in the 25-140 deg range and in the forward direction (theta = 1.5 deg), respectively. The known Compton scattering cross-section was used in a new and unique way for the determination of the elastic scattering cross-section. Isolation of the contribution of the real Delbrueck amplitudes to the cross-section was crried out successfully. Experimental confirmation of the theoretical calculations of Papatzacos and Mork and measurement, for the first time, of the Rayleigh scattering in the 10 MeV region are also reported. One of the most interesting findings is the presence of Coulomb corrections in Delbrueck scattering at these energies. More theoretical effort is needed in this last direction. (author)
DEFF Research Database (Denmark)
Gutiérrez-Chico, Juan Luis; Radu, Maria D; Diletti, Roberto
2012-01-01
Scattering centers (SC) are often observed with optical coherence tomography (OCT) in some struts of bioresorbable vascular scaffolds (BVS). These SC might be caused by crazes in the polymer during crimp-deployment (more frequent at inflection points) or by other processes, such as physiological ...
Polarization phenomena on coherent particle backscattering by random media
International Nuclear Information System (INIS)
Gorodnichev, E.E.; Dudarev, S.L.; Rogozkin, D.B.
1990-01-01
An exact solution is found for the problem of coherent enhanced backscattering of spin 1/2 particles by random media with small-radius scatterers. The polarization features in the angular spectrum are analyzed for particles reflected by three- and two-dimensional disordered systems and by medium with Anderson disorder (periodic system of random scatterers). The analysis is carried out in the case of magnetic and spin-orbit interaction with the scattering centers. The effects predicted have not any analogues on coherent backscattering of light and scalar waves
Directory of Open Access Journals (Sweden)
Mladenović Vladimir
2016-01-01
Full Text Available In this paper, a new approach in solving and analysing the performances of the digital telecommunication non-coherent FSK/ASK system in the presence of noise is derived, by using a computer algebra system. So far, most previous solutions cannot be obtained in closed form, which can be a problem for detailed analysis of complex communication systems. In this case, there is no insight into the influence of certain parameters on the performance of the system. The analysis, modelling and design can be time-consuming. One of the main reasons is that these solutions are obtained by utilising traditional numerical tools in the shape of closed-form expressions. Our results were obtained in closed-form solutions. They are resolved by the introduction of an iteration-based simulation method. The Wolfram language is used for describing applied symbolic tools, and SchematicSolver application package has been used for designing. In a new way, the probability density function and the impact of the newly introduced parameter of iteration are performed when errors are calculated. Analyses of the new method are applied to several scenarios: without fading, in the presence of Rayleigh fading, Rician fading, and in cases when the signals are correlated and uncorrelated. [Projekat Ministarstva nauke Republike Srbije, br. TR 32023
Generation of Attosecond x-ray pulse using Coherent Relativistic Nonlinear Thomson Scattering
Energy Technology Data Exchange (ETDEWEB)
Lee, Ki Tae; Park, Seong Hee; Cha, Yong Ho; Jeong, Young Uk; Lee, Byung Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2005-07-01
out by irradiating a laser pulse of 10{sup 18}-10{sup 20} W/cm{sup 2} on gas jet targets. A numerical study in the case of single electron has been attempted to characterize the RNTS radiation and a subsequent study has shown that it has a potential to generate a few attosecond x-ray pulse. The main property of RNTS radiation is believed to be incoherent. However to maintain the ultra-short characteristics of RNTS by a single electron, all the scattered radiations from a plasma should be coherently superposed, that is, the radiation intensity should increase quadratically on electron density. This motivation has led us to a condition for a coherent superposition of RNTS radiations from a plasma. The numerical simulations on this condition have been conducted and revealed that for an ultra-thin solid target, the characteristics of the RNTS radiation by single electron is indeed preserved at a specified direction and the RNTS radiation energy might exceed Bremsstrahlung radiation energy. The simulation study has been extended to the nonlinear Compton scattering, which utilizes modulated high energy electron beam. In this case, any complex plasma dynamics can be avoided and the length of the electron beam can be increased by factor of 2 compared with an ultra-thin solid target.
International Nuclear Information System (INIS)
Liu, Chao; Lee Panetta, R.; Yang, Ping
2013-01-01
Effects of surface roughness on the optical scattering properties of ice crystals are investigated using a random wave superposition model of roughness that is a simplification of models used in studies of scattering by surface water waves. Unlike previous work with models of rough surfaces applicable only in limited size ranges, such as surface perturbation methods in the small particle regime or the tilted-facet (TF) method in the large particle regime, ours uses a single roughness model to cover a range in sizes extending from the Rayleigh to the geometric optics regimes. The basic crystal shape we examine is the hexagonal column but our roughening model can be used for a wide variety of particle geometries. To compute scattering properties over the range of sizes we use the pseudo-spectral time domain method (PSTD) for small to moderate sized particles and the improved geometric optics method (IGOM) for large ones. Use of the PSTD with our roughness model is straightforward. By discretizing the roughened surface with triangular sub-elements, we adapt the IGOM to give full consideration of shadow effects, multiple reflections/refractions at the surface, and possible reentrance of the scattered beams. We measure the degree of roughness of a surface by the variance (σ 2 ) of surface slopes occurring on the surfaces. For moderately roughened surfaces (σ 2 ≤0.1) in the large particle regime, the scattering properties given by the TF and IGOM agree well, but differences in results obtained with the two methods become noticeable as the surface becomes increasingly roughened. Having a definite, albeit idealized, roughness model we are able to use the combination of the PSTD and IGOM to examine how a fixed degree of surface roughness affects the scattering properties of a particle as the size parameter of the particle changes. We find that for moderately rough surfaces in our model, as particle size parameter increases beyond about 20 the influence of surface
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
Rayleigh-Taylor mixing in supernova experiments
International Nuclear Information System (INIS)
Swisher, N. C.; Abarzhi, S. I.; Kuranz, C. C.; Arnett, D.; Hurricane, O.; Remington, B. A.; Robey, H. F.
2015-01-01
We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor instability and Rayleigh-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the Rayleigh-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of Rayleigh-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments Rayleigh-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; Rayleigh-Taylor mixing keeps order
Energy Technology Data Exchange (ETDEWEB)
Costescu, A [Department of Physics, University of Bucharest, MG11, Bucharest-Magurele 76900 (Romania); Spanulescu, S [Department of Physics, University of Bucharest, MG11, Bucharest-Magurele 76900 (Romania); Stoica, C [Department of Physics, University of Bucharest, MG11, Bucharest-Magurele 76900 (Romania)
2007-08-14
The right expressions of the nonrelativistic K-shell Rayleigh scattering amplitudes and cross-sections are obtained by using the Coulomb Green's function method. Our analytical result does not have the spurious poles that occur in the old nonrelativistic result with retardation (Gavrila and Costescu 1970 Phys. Rev. A 2 1752). Starting from the expression of the second-order S-matrix element for the case of the elastic scattering of photons by K-shell bound electrons, we obtain the correct nonrelativistic Rayleigh angular distribution (valid for photon energies {omega} up to {alpha}Zm) by removing the relativistic higher order terms in {alpha}Z and {omega}/m. The imaginary part of the Rayleigh amplitudes is obtained for any scattering angles in a closed form in terms of elementary functions. Thereby a simple formula for the exact nonrelativistic photoeffect total cross-section is obtained via the optical theorem, giving significantly better predictions than Fischer's nonrelativistic photoeffect formula. Comparing the predictions given by our formulae with the full relativistic numerical calculations of Kissel et al (Phys. Rev. 1980 A 22 1970), and with experimental results, a fairly good agreement within 10% is found for the angular distribution of Rayleigh scattering for photon energies up to 200 keV and both below and above the first resonance.
Violation of the Cauchy-Schwarz inequality in collective Raman scattering
International Nuclear Information System (INIS)
Shumovskij, A.S.; Tran Quang
1988-01-01
The violation of Cauchy-Schwarz (C-S) inequality for correlations between spectrum components of the Reyleigh line and between components of the Stokes line in the collective Raman scattering is discussed. It is shown that the violation of the C-S inequailty occurs only in the Rayleigh line, moreover, for the sidebands of the Rayleigh line the violation of the C-S inequality takes place for a large number of atoms, which means that this quantum effect has the macroscopic nature. 20 refs.; 3 figs
International Nuclear Information System (INIS)
Patel, Vishesha; Malinovsky, Vladimir S.; Malinovskaya, Svetlana
2010-01-01
Coherent anti-Stokes Raman scattering (CARS) microscopy has been a major tool of investigation of biological structures as it contains the vibrational signature of molecules. A quantum control method based on chirped pulse adiabatic passage was recently proposed for selective excitation of a predetermined vibrational mode in CARS microscopy [Malinovskaya and Malinovsky, Opt. Lett. 32, 707 (2007)]. The method utilizes the chirp sign variation at the peak pulse amplitude and gives a robust adiabatic excitation of the desired vibrational mode. Using this method, we investigate the impact of coupling between vibrational modes in molecules on controllability of excitation of the CARS signal. We analyze two models of two coupled two-level systems (TLSs) having slightly different transitional frequencies. The first model, featuring degenerate ground states of the TLSs, gives robust adiabatic excitation and maximum coherence in the resonant TLS for positive value of the chirp. In the second model, implying nondegenerate ground states in the TLSs, a population distribution is observed in both TLSs, resulting in a lack of selectivity of excitation and low coherence. It is shown that the relative phase and coupling between the TLSs play an important role in optimizing coherence in the desired vibrational mode and suppressing unwanted transitions in CARS microscopy.
A Micropulse eye-safe all-fiber molecular backscatter coherent temperature lidar
DEFF Research Database (Denmark)
Abari, Cyrus F.; Chu, Xinzhao; Mann, Jakob
2016-01-01
resolution spectrum in the baseband can be acquired. Due to the presence of a structured spectra resulting from the spontaneous Rayleigh-Brillouine scattering, associated with the relevant operating regimes, an accurate estimation of the temperature can be carried out. One of the main advantages...
International Nuclear Information System (INIS)
Krishnamachari, Vishnu Vardhan; Potma, Eric Olaf
2007-01-01
In vibrational microscopy, it is often necessary to distinguish between chemically distinct microscopic objects and to highlight the 'chemical interfaces' present in the sample under investigation. Here we apply the concept of focus engineering to enhance the sensitivity of coherent anti-Stokes Raman scattering (CARS) microscopy to these interfaces. Based on detailed numerical simulations, we show that using a focused Stokes field with a sharp phase jump along the longitudinal direction leads to the suppression of the signal from bulk regions and improves the signal contrast from vibrational resonant interfaces oriented perpendicular to the axis of beam propagation. We also demonstrate that the CARS spectral response from chemical interfaces exhibits a clean, Raman-like band-shape with such a phase-shaped excitation. This phenomenon of interface highlighting is a consequence of the coherent nature of CARS signal generation and it involves a complex interplay of the spectral phase of the sample and the spatial phase of the excitation fields
The interaction of a nanoscale coherent helium-ion probe with a crystal
International Nuclear Information System (INIS)
D'Alfonso, A.J.; Forbes, B.D.; Allen, L.J.
2013-01-01
Thickness fringing was recently observed in helium ion microscopy (HIM) when imaging magnesium oxide cubes using a 40 keV convergent probe in scanning transmission mode. Thickness fringing is also observed in electron microscopy and is due to quantum mechanical, coherent, multiple elastic scattering attenuated by inelastic phonon excitation (thermal scattering). A quantum mechanical model for elastic scattering and phonon excitation correctly models the thickness fringes formed by the helium ions. However, unlike the electron case, the signal in the diffraction plane is due mainly to the channeling of ions which have first undergone inelastic thermal scattering in the first few atomic layers so that the origin of the thickness fringes is not due to coherent interference effects. This quantum mechanical model affords insight into the interaction of a nanoscale, focused coherent ion probe with the specimen and allows us to elucidate precisely what is needed to achieve atomic resolution HIM. - Highlights: • Thickness fringing has recently been observed imaging MgO cubes using helium ion microscopy. • A quantum mechanical model for elastic scattering and phonon excitation models the fringes. • The signal is due mainly to the coherent scattering of ions after inelastic thermal scattering. • We elucidate precisely what is needed to achieve atomic resolution HIM
Dental optical coherence domain reflectometry explorer
Energy Technology Data Exchange (ETDEWEB)
Everett, Matthew J. (Livermore, CA); Colston, Jr., Billy W. (Livermore, CA); Sathyam, Ujwal S. (Livermore, CA); Da Silva, Luiz B. (Pleasanton, CA)
2001-01-01
A hand-held, fiber optic based dental device with optical coherence domain reflectometry (OCDR) sensing capabilities provides a profile of optical scattering as a function of depth in the tissue at the point where the tip of the dental explorer touches the tissue. This system provides information on the internal structure of the dental tissue, which is then used to detect caries and periodontal disease. A series of profiles of optical scattering or tissue microstructure are generated by moving the explorer across the tooth or other tissue. The profiles are combined to form a cross-sectional, or optical coherence tomography (OCT), image.
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.
Modeling of Non-WSSUS Double-Rayleigh Fading Channels for Vehicular Communications
Directory of Open Access Journals (Sweden)
Carlos A. Gutiérrez
2017-01-01
Full Text Available This paper deals with the modeling of nonstationary time-frequency (TF dispersive multipath fading channels for vehicle-to-vehicle (V2V communication systems. As a main contribution, the paper presents a novel geometry-based statistical channel model that facilitates the analysis of the nonstationarities of V2V fading channels arising at a small-scale level due to the time-varying nature of the propagation delays. This new geometrical channel model has been formulated following the principles of plane wave propagation (PWP and assuming that the transmitted signal reaches the receiver antenna through double interactions with multiple interfering objects (IOs randomly located in the propagation area. As a consequence of such interactions, the first-order statistics of the channel model’s envelope are shown to follow a worse-than-Rayleigh distribution; specifically, they follow a double-Rayleigh distribution. General expressions are derived for the envelope and phase distributions, four-dimensional (4D TF correlation function (TF-CF, and TF-dependent delay and Doppler profiles of the proposed channel model. Such expressions are valid regardless of the underlying geometry of the propagation area. Furthermore, a closed-form solution of the 4D TF-CF is presented for the particular case of the geometrical two-ring scattering model. The obtained results provide new theoretical insights into the correlation and spectral properties of small-scale nonstationary V2V double-Rayleigh fading channels.
Q-space analysis of light scattering by ice crystals
Heinson, Yuli W.; Maughan, Justin B.; Ding, Jiachen; Chakrabarti, Amitabha; Yang, Ping; Sorensen, Christopher M.
2016-12-01
Q-space analysis is applied to extensive simulations of the single-scattering properties of ice crystals with various habits/shapes over a range of sizes. The analysis uncovers features common to all the shapes: a forward scattering regime with intensity quantitatively related to the Rayleigh scattering by the particle and the internal coupling parameter, followed by a Guinier regime dependent upon the particle size, a complex power law regime with incipient two dimensional diffraction effects, and, in some cases, an enhanced backscattering regime. The effects of significant absorption on the scattering profile are also studied. The overall features found for the ice crystals are similar to features in scattering from same sized spheres.
International Nuclear Information System (INIS)
Adib, M.; Abdel-Kawy, A.; Hamouda, I.
1976-01-01
The potential scattering cross-sections for slow neutrons have been measured for Si, Ca, Cr, Mn, Co, Zn, Zr, Sb and Ta in order to determine the nuclear potential radius and to investigate the prediction of nuclear optical model. The coherent scattering cross-sections for these elements have been measured from the obtained values of the Bragg cut-offs observed in the behaviour of the total cross-sections at cold neutron energies. The measurements were based on the total neutron cross-sections resulting from transmission experiments performed with the neutron chopper at ET-RR-1 reactor
International Nuclear Information System (INIS)
Bolognini, Gabriele; Soto, Marcelo A; Di Pasquale, Fabrizio
2010-01-01
An investigation is performed of the possibility of achieving simultaneous distributed strain and temperature sensing based on hybrid Raman–Brillouin scattering with the use of multi-wavelength optical sources such as common Fabry–Perot (FP) lasers. By employing a self-heterodyne detection scheme based on a multi-wavelength optical local oscillator, the benefits of FP lasers are fully exploited, allowing for high-power Raman intensity measurements and a simultaneous high-accuracy detection of the Brillouin frequency shift parameter for each FP longitudinal mode. Experimental results point out a significant reduction of coherent Rayleigh noise, and highlight the enhanced performance in hybrid Raman–Brillouin sensing when using FP lasers; in particular using standard FP lasers at 1550 nm results in about 12 dB (7 dB) temperature (strain) accuracy improvement at 25 km sensing distance with respect to the use of standard distributed feedback lasers
International Nuclear Information System (INIS)
Sawyer, Jordan; Wu, Yue; Zhang, Zhili; Adams, Steven F.
2013-01-01
Nonintrusive spatially resolved rotational temperature measurements in an atmospheric air microdischarge are presented. The measurements were based on coherent microwave Rayleigh scattering (Radar) from resonance-enhanced multiphoton ionization of molecular oxygen. The open air DC microdischarge source operated in a stable “normal-glow” mode and pin-to-pin electrodes spaced 1.3 mm apart. The second harmonic of a tunable dye laser beam was focused between the two electrodes and scanned between 286 and 288 nm. Coherent microwave Rayleigh scattering was used to collect the two-photon rotational spectra of O 2 at C 3 Π(v = 2)←X 3 Σ(v′ = 0) transitions. The Boltzmann plots from analyses of the O 2 rotational lines determined local rotational temperatures at various axial locations between the electrodes. The molecular oxygen rotational temperature varied from ∼1150 K to ∼1350 K within the discharge area. The measurements had an accuracy of ∼±50 K.
Sawyer, Jordan; Wu, Yue; Zhang, Zhili; Adams, Steven F.
2013-06-01
Nonintrusive spatially resolved rotational temperature measurements in an atmospheric air microdischarge are presented. The measurements were based on coherent microwave Rayleigh scattering (Radar) from resonance-enhanced multiphoton ionization of molecular oxygen. The open air DC microdischarge source operated in a stable "normal-glow" mode and pin-to-pin electrodes spaced 1.3 mm apart. The second harmonic of a tunable dye laser beam was focused between the two electrodes and scanned between 286 and 288 nm. Coherent microwave Rayleigh scattering was used to collect the two-photon rotational spectra of O2 at C3Π(v = 2)←X3Σ(v' = 0) transitions. The Boltzmann plots from analyses of the O2 rotational lines determined local rotational temperatures at various axial locations between the electrodes. The molecular oxygen rotational temperature varied from ˜1150 K to ˜1350 K within the discharge area. The measurements had an accuracy of ˜±50 K.
Low-energy scattering data for oxygen
International Nuclear Information System (INIS)
Kopecky, S.; Plompen, A.J.M.
2014-01-01
A survey of literature data of the scattering lengths of oxygen is performed, and these values are compared to low-energy precise total cross-section data. To check the quality of the data and the correctness of the relation between coherent scattering lengths and low-energy total cross-sections the situation is examined first for carbon. A value and uncertainty for the coherent scattering length of oxygen is recommended for use in future evaluations of 16 O. This coherent scattering length is fully consistent with the high-precision, low-energy total cross-section data. The consistency requires the use of a larger uncertainty than claimed in the most accurate cross-section papers. This larger uncertainty is nevertheless very small and well within the requirements of applications of this cross-section. The recommended value is b c ( 16 O) = 5.816±0.015 fm and the associated total cross-section for the neutron-energy range 0.5 to 2 000 eV is 3.765±0.025 b. The stated uncertainties are one standard deviation total uncertainty. (authors)
2004-01-01
For the first time in one set of books, coherent-domain optical methods are discussed in the framework of various applications, which are characterized by a strong light scattering. A few chapters describe basic research containing the updated results on coherent and polarized light non-destructive interactions with a scattering medium, in particular, diffraction, interference, and speckle formation at multiple scattering. These chapters allow for understanding coherent-domain diagnostic techniques presented in later chapters. A large portion of Volume I is dedicated to analysis of various aspects of optical coherence tomography (OCT) - a very new and growing field of coherent optics. Two chapters on laser scanning confocal microscopy give insight to recent extraordinary results on in vivo imaging and compare the possibilities and achievements of confocol, excitation multiphoton, and OCT microscopy. This two volume reference contains descriptions of holography, interferometry and optical heterodyning techniqu...
Energy Technology Data Exchange (ETDEWEB)
Perrett, Glynis M. [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Campbell, John L., E-mail: icampbel@uoguelph.ca [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Gellert, Ralf [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); King, Penelope L. [Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 (Australia); Nield, Emily; O’Meara, Joanne M.; Pradler, Irina [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)
2016-02-01
The intensity ratio C/R between Compton and Rayleigh scatter peaks of the exciting Pu L X-rays in the alpha particle X-ray spectrometer (APXS) is strongly affected by the presence of very light elements such as oxygen which cannot be detected directly by the APXS. C/R values are determined along with element concentrations by fitting APXS spectra of geochemical reference materials (GRMs) with the GUAPX code. A quantity K is defined as the ratio between the C/R value determined by Monte Carlo simulation based on the measured element concentrations and the fitted C/R value from the spectrum. To ensure optimally accurate K values, the choice of appropriate GRMs is explored in detail, with attention paid to Rb and Sr, whose characteristic Kα X-ray peaks overlap the Pu Lα scatter peaks. The resulting relationship between the ratio K and the overall oxygen fraction is linear. This provides a calibration from which the concentration of additional light invisible constituents (ALICs) such as water may be estimated in unknown rock and conglomerate samples. Several GRMs are used as ‘unknowns’ in order to evaluate the accuracy of ALIC concentrations derived in this manner.
Bae, Kideog; Zheng, Wei; Huang, Zhiwei
2017-08-01
We report the quantitative assessment of spinal cord injury using the circularly polarized coherent anti-Stokes Raman scattering (CP-CARS) technique together with Stokes parameters in the Poincaré sphere. The pump and Stokes excitation beams are circularly polarized to suppress both the linear polarization-dependent artifacts and the nonresonant background of tissue CARS imaging, enabling quantitative CP-CARS image analysis. This study shows that CP-CARS imaging uncovers significantly increased phase retardance of injured spinal cord tissue as compared to normal tissue, suggesting that CP-CARS is an appealing label-free imaging tool for determining the degree of tissue phase retardance, which could serve as a unique diagnostic parameter associated with nervous tissue injury.
International Nuclear Information System (INIS)
Bergner, G; Akimov, D; Bartelt, H; Dietzek, B; Popp, J; Schlücker, S
2011-01-01
A simplified setup for coherent anti-Stokes Raman scattering (CARS) microscopy is introduced, which allows for recording CARS images with 30 cm -1 excitation bandwidth for probing Raman bands between 500 and 900 cm -1 with minimal requirements for alignment. The experimental arrangement is based on electronic switching between CARS images recorded at different Raman resonances by combining a photonic crystal fiber (PCF) as broadband light source and an acousto-optical programmable dispersive filter (AOPDF) as tunable wavelength filter. Such spatial light modulator enables selection of a narrow-band spectrum to yield high vibrational contrast and hence chemical contrast in the resultant CARS images. Furthermore, an experimental approach to reconstruct spectral information from CARS image contrast is introduced
Experimental study on stimulated scattering of ZnO nanospheres dispersed in water
Energy Technology Data Exchange (ETDEWEB)
Shi, Jiulin, E-mail: hyq1304@126.com; Wu, Haopeng [Nanchang Hangkong University, Jiangxi Engineering Laboratory for Optoelectronics Testing Technology (China); Yan, Feng; Yang, Junjie [Nanchang Hangkong University, School of Measuring and Optical Engineering (China); He, Xingdao, E-mail: xingdaohe@126.com [Nanchang Hangkong University, Jiangxi Engineering Laboratory for Optoelectronics Testing Technology (China)
2016-01-15
The backward stimulated scattering (BSS) from ZnO nanospheres dispersed in water has been investigated experimentally by employing a Nd:YAG pulse laser with ∼532 nm wavelength and ∼8 ns pulse width as the pump laser source. The present results show that the BSS effect is uniquely and unequivocally different compared to other known stimulated scattering, such as stimulated Rayleigh scattering, stimulated Brillouin scattering, and stimulated Raman scattering, and it displays the characteristics of no frequency shift and threshold dependence on initial spontaneous Mie scattering seed source. These can be understood by means of the Mie scattering theory and a laser-induced stationary Bragg grating model.
Ramm, Alexander G
2013-01-01
The behavior of acoustic or electromagnetic waves reflecting off, and scattering from, intercepted bodies of any size and kind can make determinations about the materials of those bodies and help in better understanding how to manipulate such materials for desired characteristics. This book offers analytical formulas which allow you to calculate acoustic and electromagnetic waves, scattered by one and many small bodies of an arbitrary shape under various boundary conditions. Equations for the effective (self-consistent) field in media consisting of many small bodies are derived. These results and formulas are new and not available in the works of other authors. In particular, the theory developed in this book is different from the classical work of Rayleigh on scattering by small bodies: not only analytical formulas are derived for the waves scattered by small bodies of an arbitrary shape, but the amplitude of the scattered waves is much larger, of the order O(a 2-k), than in Rayleigh scattering, where the or...
Nonlinear Rayleigh-Taylor instability in partially ionized plasma and the equatorial spread - F
International Nuclear Information System (INIS)
Jain, R.K.; Das, A.C.
1978-01-01
The nonlinear evolution of the collisional gravitation induced Rayleigh-Taylor (R-T) instability in the equatorial F region is investigated taking into account the finite Larmor radius (FLR) effects and the complete ion inertial term in ion equation of motion. A special class of coherent weakly nonlinear modes as solutions to the wave equation describing R-T instability driven modes is obtained. The leading nonlinear effects in the wave equation are found to appear through Vsub(L), the ion diamagnetic drift which essentially gives the FLR corrections. It is shown that the R-T modes in the equatorial F region can evolve into coherent, nonlinear, almost sinusoidal, stationary wave structures. These structures are found to travel with a constant phase velocity and to have slightly distorted sinusoidal shapes. These results seem to have a good agreement with many of the recent rocket and satellite observations of the equatorial spread F irregularities. (author)
Directory of Open Access Journals (Sweden)
R Dariani
2015-01-01
Full Text Available Reflection spectra of four porous silicon samples under etching times of 2, 6, 10, and 14 min with current density of 10 mA/cm2 were measured. Reflection spectra behaviors for all samples were the same, but their intensities were different and decreased by increasing the etching time. The similar behavior of reflection spectra could be attributed to the electrolyte solution concentration which was the same during fabrication and reduction of reflection spectrum due to the reduction of particle size. Also, the region for the lowest intensity at reflection spectra was related to porous silicon energy gap which shows blue shift for porous silicon energy gap. Roughness study of porous silicon samples was done by scattering spectra measurements, Rayleigh criteria, and Davis-Bennet equation. Scattering spectra of the samples were measured at 10, 15, and 20 degrees by using spectrophotometer. Reflected light intensity reduced by increasing the scattering angle except for the normal scattering which agreed with Rayleigh criteria. Also, our results showed that by increasing the etching time, porosity (sizes and numbers of pores increases and therefore light absorption increases and scattering from surface reduces. But since scattering varies with the observation scale (wavelength, the relationship between scattering and porosity differs by varying the observation scale (wavelength
Collective scattering of electromagnetic waves and cross-B plasma diffusion
International Nuclear Information System (INIS)
Gresillon, D.; Cabrit, B.; Truc, A.
1992-01-01
Magnetized plasmas occuring in nature as well as in fusion laboratories are oftenly irregularly shaked by magnetic field fluctuations. The so-called ''coherent scattering'' of electromagnetic wave from nonuniform, irregularly moving plasmas is investigated in the case where the scattering wavelength is large compared to the Debye length, but of the order of the irregularities correlation length. The scattered signal frequency spectrum is shown to be a transform of the plasma motion statistical characteristics. When the scattering wavelength is larger than the plasma motion correlation length, the frequency spectrum is shown to be of a lorentzian shape, with a frequency width that provides a direct measurement of the cross-B particle diffusion coefficient. This is illustrated by two series of recently obtained experimental results: radar coherent backscattering observations of the auroral plasma, and far infrared scattering from tokamak fusion plasma. Radar coherent backscattering shows the transition from Gauss to Lorentz scattered frequency spectra. In infrared Laser coherent scattering experiments from the Tore-Supra tokamak, a particular frequency line is observed to present a Lorentzian shape, that directly provides an electron cross-field diffusion coefficient. This diffusion coefficient agrees with the electron heat conductivity coefficient that is obtained from the observation of temperature profiles and energy balance. (Author)
Coherent Control of Four-Wave Mixing
Zhang, Yanpeng; Xiao, Min
2011-01-01
"Coherent Control of Four-Wave Mixing" discusses the frequency, temporal and spatial domain interplays of four-wave mixing (FWM) processes induced by atomic coherence in multi-level atomic systems. It covers topics in five major areas: the ultrafast FWM polarization beats due to interactions between multi-color laser beams and multi-level media; coexisting Raman-Rayleigh-Brillouin-enhanced polarization beats due to color-locking noisy field correlations; FWM processes with different kinds of dual-dressed schemes in ultra-thin, micrometer and long atomic cells; temporal and spatial interference between FWM and six-wave mixing (SWM) signals in multi-level electromagnetically induced transparency (EIT) media; spatial displacements and splitting of the probe and generated FWM beams, as well as the observations of gap soliton trains, vortex solitons, and stable multicomponent vector solitons in the FWM signals. The book is intended for scientists, researchers, advanced undergraduate and graduate students in Nonlin...
Neutron scattering lengths of 3He
International Nuclear Information System (INIS)
Alfimenkov, V.P.; Akopian, G.G.; Wierzbicki, J.; Govorov, A.M.; Pikelner, L.B.; Sharapov, E.I.
1976-01-01
The total neutron scattering cross-section of 3 He has been measured in the neutron energy range from 20 meV to 2 eV. Together with the known value of coherent scattering amplitude it leads to the two sts of n 3 He scattering lengths
International Nuclear Information System (INIS)
Lu, Chenhui; Zhang, Shian; Wu, Meizhen; Jia, Tianqing; Sun, Zhenrong; Qiu, Jianrong
2013-01-01
Femtosecond coherent anti-Stokes Raman scattering (CARS) spectra suffer from low spectral resolution because of the broadband laser spectrum. In this paper, we propose a feasible scheme to achieve a high-resolution two-pulse CARS spectrum by shaping both the pump and probe pulses using rectangular amplitude modulation. We show that a narrowband hole in the CARS spectrum can be created by the amplitude-shaped laser pulse, the position of which is correlated with the Raman resonant frequency of the molecule. Thus, by observing holes in the CARS spectrum, we are able to obtain a high-resolution CARS spectrum and the energy-level diagram of the molecule. (paper)
International Nuclear Information System (INIS)
Ito, Tsuyohito; Kobayashi, Kazunobu; Hamaguchi, Satoshi; Mueller, Sarah; Luggenhoelscher, Dirk; Czarnetzki, Uwe
2009-01-01
The feasibility of electric field measurement based on field-induced coherent Raman scattering is demonstrated for the first time in a nitrogen containing gas at atmospheric or higher pressure, including open air. The technique is especially useful for the determination of temporal and spatial profiles of the electric field in air-based microdischarges, where nitrogen is abundant. In our current experimental setup, the minimum detectable field strength in open air is about 100 V mm -1 , which is sufficiently small compared with the average field present in typical microdischarges. No further knowledge of other gas/plasma parameters such as the nitrogen density is required. (fast track communication)
Rayleigh beacon for measuring the surface profile of a radio telescope.
Padin, S
2014-12-01
Millimeter-wavelength Rayleigh scattering from water droplets in a cloud is proposed as a means of generating a bright beacon for measuring the surface profile of a radio telescope. A λ=3 mm transmitter, with an output power of a few watts, illuminating a stratiform cloud, can generate a beacon with the same flux as Mars in 10 GHz bandwidth, but the beacon has a narrow line width, so it is extremely bright. The key advantage of the beacon is that it can be used at any time, and positioned anywhere in the sky, as long as there are clouds.
Short Rayleigh Length Free Electron Lasers
Crooker, P P; Armstead, R L; Blau, J
2004-01-01
Conventional free electron laser (FEL) oscillators minimize the optical mode volume around the electron beam in the undulator by making the resonator Rayleigh length about one third of the undulator length. This maximizes gain and beam-mode coupling. In compact configurations of high-power infrared FELs or moderate power UV FELs, the resulting optical intensity can damage the resonator mirrors. To increase the spot size and thereby reduce the optical intensity at the mirrors below the damage threshold, a shorter Rayleigh length can be used, but the FEL interaction is significantly altered. A new FEL interaction is described and analyzed with a Rayleigh length that is only one tenth the undulator length, or less. The effect of mirror vibration and positioning are more critical in the short Rayleigh length design, but we find that they are still within normal design tolerances.
COHERENT Experiment: current status
International Nuclear Information System (INIS)
Akimov, D; Belov, V; Bolozdynya, A; Burenkov, A; Albert, J B; Del Valle Coello, M; D’Onofrio, M; Awe, C; Barbeau, P S; Cervantes, M; Becker, B; Cabrera-Palmer, B; Collar, J I; Cooper, R J; Cooper, R L; Cuesta, C; Detwiler, J; Eberhardt, A; Dean, D; Dolgolenko, A G
2017-01-01
The COHERENT Collaboration is realizing a long term neutrino physics research program. The main goals of the program are to detect and study elastic neutrino-nucleus scattering (CEνNS). This process is predicted by Standard Model but it has never been observed experimentally because of the very low energy of the recoil nucleus. COHERENT is using different detector technologies: CsI[Na] and NaI scintillator crystals, a single-phase liquid Ar and a Ge detectors. The placement of all the detector setups is in the basement of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The current status of the COHERENT experimental program is presented. (paper)
Scattering theory of infrared divergent Pauli-Fierz Hamiltonians
Derezinski, J
2003-01-01
We consider in this paper the scattering theory of infrared divergent massless Pauli-Fierz Hamiltonians. We show that the CCR representations obtained from the asymptotic field contain so-called {\\em coherent sectors} describing an infinite number of asymptotically free bosons. We formulate some conjectures leading to mathematically well defined notion of {\\em inclusive and non-inclusive scattering cross-sections} for Pauli-Fierz Hamiltonians. Finally we give a general description of the scattering theory of QFT models in the presence of coherent sectors for the asymptotic CCR representations.
DEFF Research Database (Denmark)
Fercher, A.F.; Andersen, Peter E.
2017-01-01
Optical coherence tomography (OCT) is a technique that is used to peer inside a body noninvasively. Tissue structure defined by tissue absorption and scattering coefficients, and the speed of blood flow, are derived from the characteristics of light remitted by the body. Singly backscattered light...... detected by partial coherence interferometry (PCI) is used to synthesize the tomographic image coded in false colors. A prerequisite of this technique is a low time-coherent but high space-coherent light source, for example, a superluminescent diode or a supercontinuum source. Alternatively, the imaging...... technique can be realized by using ultrafast wavelength scanning light sources. For tissue imaging, the light source wavelengths are restricted to the red and near-infrared (NIR) region from about 600 to 1300 nm, the so-called therapeutic window, where absorption (μa ≈ 0.01 mm−1) is small enough. Transverse...
Large-scale patterns in Rayleigh-Benard convection
International Nuclear Information System (INIS)
Hardenberg, J. von; Parodi, A.; Passoni, G.; Provenzale, A.; Spiegel, E.A.
2008-01-01
Rayleigh-Benard convection at large Rayleigh number is characterized by the presence of intense, vertically moving plumes. Both laboratory and numerical experiments reveal that the rising and descending plumes aggregate into separate clusters so as to produce large-scale updrafts and downdrafts. The horizontal scales of the aggregates reported so far have been comparable to the horizontal extent of the containers, but it has not been clear whether that represents a limitation imposed by domain size. In this work, we present numerical simulations of convection at sufficiently large aspect ratio to ascertain whether there is an intrinsic saturation scale for the clustering process when that ratio is large enough. From a series of simulations of Rayleigh-Benard convection with Rayleigh numbers between 10 5 and 10 8 and with aspect ratios up to 12π, we conclude that the clustering process has a finite horizontal saturation scale with at most a weak dependence on Rayleigh number in the range studied
Neutron Inelastic Scattering Study of Liquid Argon
Energy Technology Data Exchange (ETDEWEB)
Skoeld, K; Rowe, J M; Ostrowski, G [Solid State Science Div., Argonne National Laboratory, Argonne, Illinois (US); Randolph, P D [Nuclear Technology Div., Idaho Nuclear Corporation, Idaho Falls, Idaho (US)
1972-02-15
The inelastic scattering functions for liquid argon have been measured at 85.2 K. The coherent scattering function was obtained from a measurement on pure A-36 and the incoherent function was derived from the result obtained from the A-36 sample and the result obtained from a mixture of A-36 and A-40 for which the scattering is predominantly incoherent. The data, which are presented as smooth scattering functions at constant values of the wave vector transfer in the range 10 - 44/nm, are corrected for multiple scattering contributions and for resolution effects. Such corrections are shown to be essential in the derivation of reliable scattering functions from neutron scattering data. The incoherent data are compared to recent molecular dynamics results and the mean square displacement as a function of time is derived. The coherent data are compared to molecular dynamics results and also, briefly, to some recent theoretical models
Guo, L.-J.; Huang, Y.-M.; Bhattacharjee, A.; Innes, D. E.
2014-12-01
Supra-arcade downflows (hereafter referred to as SADs) are low-emission, elongated, finger-like features observed in active region coronae above post-eruption flare arcades. Observations exhibit downward moving SADs intertwined with bright upward growing spikes. Whereas SADs are dark voids, spikes are brighter, denser structures. Although SADs have been observed for more than a decade, the mechanism of the formation of SADs remains an open issue. Using three-dimensional resistive magnetohydrodynamic simulations, we demonstrate that Rayleigh-Taylor-type instabilities develop in the downstream region of a reconnecting current sheet. The instabilities result in the formation of low-density coherent structures that resemble SADs, and high-density structures that appear to be spike-like. Comparison between the simulation results and observations suggests that Rayleigh-Taylor-type instabilities in the exhaust of reconnecting current sheets provide a plausible mechanism for observed SADs.
International Nuclear Information System (INIS)
Chaturvedi, D.K.; Tosi, M.P.
1987-08-01
Neutron scattering experiments on SrCl 2 , CaF 2 and PbF 2 have shown that intensity and width of the coherent diffuse quasi-elastic spectrum increase rapidly with temperature into the fast-ion conducting phase, the main feature in the integrated quasi-elastic intensity being a peak just beyond the (200) point along the (100) direction in scattering wave vector space. The Zwanzig-Mori memory function formalism is used in this work to analyze the quasi-elastic scattering cross section from charge density fluctuations in terms of anharmonic couplings between the vibrational modes of the crystal. The two- and three-mode channels are examined for compatibility with the quasi-elastic neutron scattering evidence, on the basis of (i) energy and momentum conservation and van Hove singularity arguments and (ii) measured phonon dispersion curves along the main symmetry directions in SrCl 2 , CaF 2 , SrF 2 and BaF 2 . The analysis identifies a specific microscopic role for the Raman-active optic branches. The eigenvectors of the relevant Raman-active and partner modes in the three-mode channel describe relative displacements of the two halogens in the unit cell superposed on relative displacements of the halogen and alkaline earth components. This microscopic picture is thus consistent with the superionic transition being associated with the onset of dynamic disorder in the anionic component of the crystal. (author). 13 refs, 2 tabs
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)
Acoustofluidic particle dynamics: Beyond the Rayleigh limit.
Baasch, Thierry; Dual, Jürg
2018-01-01
In this work a numerical model to calculate the trajectories of multiple acoustically and hydrodynamically interacting spherical particles is presented. The acoustic forces are calculated by solving the fully coupled three-dimensional scattering problem using finite element software. The method is not restricted to single re-scattering events, mono- and dipole radiation, and long wavelengths with respect to the particle diameter, thus expanding current models. High frequency surface acoustic waves have been used in the one cell per well technology to focus individual cells in a two-dimensional wave-field. Sometimes the cells started forming clumps and it was not possible to focus on individual cells. Due to a lack of existing theory, this could not be fully investigated. Here, the authors use the full dynamic simulations to identify limiting factors of the one-cell-per-well technology. At first, the authors demonstrate good agreement of the numerical model with analytical results in the Rayleigh limiting case. A frequency dependent stability exchange between the pressure and velocity was then demonstrated. The numerical formulation presented in this work is relatively general and can be used for a multitude of different high frequency applications. It is a powerful tool in the analysis of microscale acoustofluidic devices and processes.
Quantum theory of scattering of channeled electrons and positrons in a crystal
International Nuclear Information System (INIS)
Bazylev, V.A.; Goloviznin, V.V.
1982-01-01
The quantum theory of elastic scattering of electrons and positrons on plane or axial channeling in a thin crystal is developed. The role of coherent (without phonon excitation) and incoherent scattering by atoms of the plane (chain) is investigated. It is shown that incoherent scattering which leads to dechanneling cannot be reduced to scattering by an isolated atom. Allowance for ordered arrangement of the atoms in the plane (chain) of the crystal leads to suppression of the motion levels. It is also shown that on movement of a particle along the plane in directions strongly differing from those of the principal axes, the scattering is incoherent and is determined by thermal vibrations of the nuclei. As the direction of the particle momentum approaches those of the principal axes, the role of coherent scattering without recoil by the crystal lattice nuclei increases and may become dicisive. The probability of large- angle scattering increases relatively in this case. Under certain conditions coherent scattering may become resonant [ru
International Nuclear Information System (INIS)
Antoniassi, M.; Conceicao, A.L.C.; Poletti, M.E.
2011-01-01
In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90 o (x=0.99 A -1 ). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number (Z eff ) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Z eff of breast tissues, which are mainly related to the elemental composition of carbon (Z=6) and oxygen (Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.
Antoniassi, M.; Conceição, A. L. C.; Poletti, M. E.
2011-10-01
In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90° ( x=0.99 Å -1). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number ( Zeff) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Zeff of breast tissues, which are mainly related to the elemental composition of carbon ( Z=6) and oxygen ( Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.
Energy Technology Data Exchange (ETDEWEB)
Luo, Yanghe [School of Food and Bioengineering, Hezhou University, Hezhou 542899 (China); Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection of Ministry Education, Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guangxi Normal University, Guilin 541004 (China); Li, Chongnin; Qin, Aimian [Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection of Ministry Education, Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guangxi Normal University, Guilin 541004 (China); Liang, Aihui, E-mail: ahliang2008@163.com [Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection of Ministry Education, Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guangxi Normal University, Guilin 541004 (China); Jiang, Zhiliang, E-mail: zljiang@mailbox.gxnu.edu.cn [School of Food and Bioengineering, Hezhou University, Hezhou 542899 (China); Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection of Ministry Education, Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guangxi Normal University, Guilin 541004 (China)
2017-05-15
In pH 7.2 KH{sub 2}PO{sub 4}-NaOH buffer solution, graphene oxide (GO) has strong resonance Rayleigh scattering (RRS) effect at 400 nm, and amino acid reacted with ninhydrin to form blue-violet complex Ruhemann's purple (RP) with a absorption peak at 400 nm. RPs can strongly adsorbed on the surface of GO, and the RRS donor of GO probes coupled with the receptor of RP that reduced the RRS intensity at 400 nm due to the RRS-energy transfer (RRS-ET) from the GO to RP. With the increase of amino acid concentration, the RRS intensity quenched linearly at 400 nm due to the RRS-ET enhancing. The quenched intensity responds linearly with glutamic acid concentration in the range of 0.2–200 μmol L{sup −1}, with a detection limit of 0.08 µmol L{sup −1}. This simple and sensitive RRS-ET method was used to detect the content of amino acid in oral liquid, with satisfactory results.
Paolantoni, Marco; Sassi, Paola; Morresi, Assunta; Santini, Sergio
2007-07-01
The effect of glucose on the relaxation process of water at picosecond time scales has been investigated by depolarized Rayleigh scattering (DRS) experiments. The process is assigned to the fast hydrogen bonding dynamics of the water network. In DRS spectra this contribution can be safely separated from the slower relaxation process due to the sugar. The detected relaxation time is studied at different glucose concentrations and modeled considering bulk and hydrating water contributions. As a result, it is found that in diluted conditions the hydrogen bond lifetime of proximal water molecules becomes about three times slower than that of the bulk. The effect of the sugar on the hydrogen bond water structure is investigated by analyzing the low-frequency Raman (LFR) spectrum sensitive to intermolecular modes. The addition of glucose strongly reduces the intensity of the band at 170cm-1 assigned to a collective stretching mode of water molecules arranged in cooperative tetrahedral domains. These findings indicate that proximal water molecules partially lose the tetrahedral ordering typical of the bulk leading to the formation of high density environments around the sugar. Thus the glucose imposes a new local order among water molecules localized in its hydration shell in which the hydrogen bond breaking dynamics is sensitively retarded. This work provides new experimental evidences that support recent molecular dynamics simulation and thermodynamics results.
Performance of equal gain combining with quantized phases in rayleigh fading channels
Rizvi, Umar H.
2011-01-01
In this paper, we analyze the error probability of equal gain combining with quantized channel phase compensation for binary phase shift keying signalling over Rayleigh fading channels. The probability density and characteristic functions of the combined signal amplitude are derived and used to compute the analytic expressions for the bit error probability in dependance of the number of quantization levels L, the number of diversity branches N-R and the average received signal-to-noise ratio. The analysis is utilized to outline the trade-off between N-R and L and to compare the performance with non-coherent binary frequency shift keying and differential binary phase shift keying schemes under diversity reception. © 2011 IEEE.
Rayleigh wave effects in an elastic half-space.
Aggarwal, H. R.
1972-01-01
Consideration of Rayleigh wave effects in a homogeneous isotropic linearly elastic half-space subject to an impulsive uniform disk pressure loading. An approximate formula is obtained for the Rayleigh wave effects. It is shown that the Rayleigh waves near the center of loading arise from the portion of the dilatational and shear waves moving toward the axis, after they originate at the edge of the load disk. A study is made of the vertical displacement due to Rayleigh waves at points on the axis near the surface of the elastic half-space.
Quasielastic Neutron Scattering by Superionic Strontium Chloride
DEFF Research Database (Denmark)
Dickens, M. H.; Hutchings, M. T.; Kjems, Jørgen
1978-01-01
The scattering, from powder and single crystal samples, appears only above the superionic transition temperature, 1000K. The integrated intensity is found to be strongly dependent on the direction and magnitude of the scattering vector, Q, (which suggests the scattering is coherent) but does not ...
Theory of neutron scattering in disordered alloys
International Nuclear Information System (INIS)
Yussouff, M.; Mookerjee, A.
1984-08-01
A comprehensive theory of thermal neutron scattering in disordered alloys is presented here. We consider in detail the case of substitutional random binary alloy with random changes in mass and force constants; and for all values of the concentration. The cluster CPA formalism in argumented space developed here is free from analytical difficulties for the Green function, performs correct averaging over random atomic scattering lengths and employs a self-consistent medium for the calculations. For easy computation, we describe the graphical representation of the resolvent where the approximation steps can be depicted as closed paths in augmented space. Our results for scattering cross sections, both coherent and incoherent, include new types of terms and these lead to asymmetric line shapes for the coherent scattering. (author)
Directory of Open Access Journals (Sweden)
Weiai Zhang
2016-04-01
Full Text Available This work describes a highly-sensitive and accurate approach for the determination of chitosan (CTS using Naphthol Green B (NGB as a probe in the Resonance Rayleigh scattering (RRS method. The interaction between CTS and NGB leads to notable enhancement of RRS, and the enhancement is proportional to the concentration of CTS over a certain range. Under optimum conditions, the calibration curve of ΔI against CTS concentration was ΔI = 1860.5c + 86.125 (c, µg/mL, R2 = 0.9999, and the linear range and detection limit (DL were 0.01–5.5 µg/mL and 8.87 ng/mL. Moreover, the effect of the molecular weight of CTS on the accurate quantification of CTS was studied. The experimental data were analyzed through linear regression analysis using SPSS20.0, and the molecular weight was found to have no statistical significance. This method has been applied to assay two CTS samples and obtained good recovery and reproducibility.
The interpretation of the intensity of components of laser scattering by interaction with matter
Fidanovski, Z.; Srećković, M.; Ostojić, S.; Ilić, J.; Merkle, M.
2012-05-01
The measurement of scattered light properties offers many optical, acoustic, dielectric, thermodynamic data about the scattering medium. Brillouin spectroscopy with various modifications and different laser types has been a measurement technique in acoustics for a long time, but it is still important as an autonomous technique. It enables more detailed and exhaustive knowledge of the acoustic and optical properties of matter. A series of Rayleigh-Brillouin spectra are recorded for a set of organic solvents and phytol. The equipment used in spectra recordings enables the measurement of four components of scattered laser intensity Ihh, Ihv, Ivv and Ivh. The ratios of the linewidth, as well as shifts, are determined for Rayleigh-Brillouin spectra. According to them, the hypersound velocity and absorption coefficients can be calculated. There is much software for data processing obtained in laser interaction with matter, with different programming tools. An analysis of spectra is performed, i.e. an examination of which distribution (Gaussian or Lorentzian) better explains the experimentally obtained diagrams.
Bivariate Rayleigh Distribution and its Properties
Directory of Open Access Journals (Sweden)
Ahmad Saeed Akhter
2007-01-01
Full Text Available Rayleigh (1880 observed that the sea waves follow no law because of the complexities of the sea, but it has been seen that the probability distributions of wave heights, wave length, wave induce pitch, wave and heave motions of the ships follow the Rayleigh distribution. At present, several different quantities are in use for describing the state of the sea; for example, the mean height of the waves, the root mean square height, the height of the “significant waves” (the mean height of the highest one-third of all the waves the maximum height over a given interval of the time, and so on. At present, the ship building industry knows less than any other construction industry about the service conditions under which it must operate. Only small efforts have been made to establish the stresses and motions and to incorporate the result of such studies in to design. This is due to the complexity of the problem caused by the extensive variability of the sea and the corresponding response of the ships. Although the problem appears feasible, yet it is possible to predict service conditions for ships in an orderly and relatively simple manner Rayleigh (1980 derived it from the amplitude of sound resulting from many independent sources. This distribution is also connected with one or two dimensions and is sometimes referred to as “random walk” frequency distribution. The Rayleigh distribution can be derived from the bivariate normal distribution when the variate are independent and random with equal variances. We try to construct bivariate Rayleigh distribution with marginal Rayleigh distribution function and discuss its fundamental properties.
International Nuclear Information System (INIS)
Requardt, M.
1984-01-01
In this paper we want to discuss the quantum mechanical measuring process within the realm of many body quantum theory. Our starting point is to consider this process as a special scattering phenomenon where within one of the partners, i.e. the many body measuring device, a collective coherent motion is induced by the interaction with the microobject. We start our investigation with the many body system having a large but finite number N of degrees of freedom which is the real situation. We then study in detail what will happen in the limit N->infinite, however emphasizing that this transition is actually only performed in the mind of the observer. This implies that certain tail events together with their phase correlations have to be truncated. We show that the dichotomy 'pure state' versus 'mixture' as outgoing scattering states will vanish in this limit in so far as it has no observable consequences provided one is only interested in the state of the microobject. Furthermore, we discuss the role of the observer, the notion of 'event', the relation between single preparation and ensemble picture, and the so-called 'reduction of the wave function' in the light of our approach, i.e. explaining the phenomena accompanying the measuring process in terms of many body quantum theory. (orig.)
International Nuclear Information System (INIS)
Agababyan, N.M.; Galoyan, A.S.; Enkovskij, L.L.; Zarubin, P.I.; Malakhov, A.I.; Melkumov, G.L.; Chatrchyan, S.A.
1999-01-01
The double coherent and non-coherent diffractive production of heavy quark-antiquark pairs (QQ-bar) in heavy ion scattering at high energies (LHC) is considered. The total and differential cross sections of these processes with the formation of cc-bar and bb-bar pairs in pp, CaCa and PbPb collisions are evaluated. The contribution of the considered mechanisms is a few per cent of the number of heavy quark-antiquark pairs obtained in the processes of hard (QCD) scattering, and it will be taken into account in the registration of c, b quarks or, for instance, in the study of the heavy quarkonia suppression effect in Quark-Gluon Plasma, in the search got intermediate mass Higgs bosons and so on. It is shown that the cross section of the coherently scattering process is great enough. This makes it suitable for studying collective effects in nuclear interactions at high energies. An example of such effects is given: large values of the invariant mass of a QQ-bar pair, M QQ-bar ≥ 100 GeV, in association with a large rapidity gap between diffractive jets Δη >5 [ru
International Nuclear Information System (INIS)
Agababyan, N.M.; Chatrchyan, S.A.; Galoyan, A.S.; Malakhov, A.I.; Melkumov, G.L.; Zarubin, P.I.; Jenkovszky, L.L.
1998-01-01
The double coherent and non-coherent diffractive production of heavy quark-antiquark pair (QQ-bar) in heavy ion scattering at high energies (LHC) is considered. The total and differential cross sections of these processes with the formation of cc bar and bb bar pairs in pp, CaCa and PbPb collisions are evaluated. The contribution of the considered mechanisms is a few per cent of the number of heavy quark-antiquark pairs obtained in the processes of hard (QCD) scattering, and it will be taken into account in the registration of c, b quarks or, for instance, in the study of the heavy quarkonia suppression effects in quark-gluon plasma, in the search for intermediate mass Higgs bosons and so on. It is shown that the cross section of the coherent scattering process is great enough. This makes it suitable for studying collective effects in nuclear interactions at high energies. An example of such effects is given: large values of the invariant mass of a QQ- bar pair, M QQb ar ≥ 100 GeV, in association with a large rapidity gap between diffractive jets Δη>5
Schwinger–Keldysh canonical formalism for electronic Raman scattering
Energy Technology Data Exchange (ETDEWEB)
Su, Yuehua, E-mail: suyh@ytu.edu.cn
2016-03-01
Inelastic low-energy Raman and high-energy X-ray scatterings have made great progress in instrumentation to investigate the strong electronic correlations in matter. However, theoretical study of the relevant scattering spectrum is still a challenge. In this paper, we present a Schwinger–Keldysh canonical perturbation formalism for the electronic Raman scattering, where all the resonant, non-resonant and mixed responses are considered uniformly. We show how to use this formalism to evaluate the cross section of the electronic Raman scattering off an one-band superconductor. All the two-photon scattering processes from electrons, the non-resonant charge density response, the elastic Rayleigh scattering, the fluorescence, the intrinsic energy-shift Raman scattering and the mixed response, are included. In the mean-field superconducting state, Cooper pairs contribute only to the non-resonant response. All the other responses are dominated by the single-particle excitations and are strongly suppressed due to the opening of the superconducting gap. Our formalism for the electronic Raman scattering can be easily extended to study the high-energy resonant inelastic X-ray scattering.
Scattering cross-sections of common calibration gases measured by IBBCEAS technique
Directory of Open Access Journals (Sweden)
S.I. Issac
Full Text Available In this study, incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS was used to measure scattering cross-sections of a few common gases in the 650–670 nm spectral range relative to that of dry air. Precise measurements of scattering cross-sections of these calibration gases in the visible spectral range are important. The IBBCEAS system developed in the laboratory was calibrated with a low-loss optical window. The measurements made at 660 nm were compared with previously measured cross-section values and found to be in good agreement with the existing measurements. Keywords: IBBCEAS, Rayleigh scattering, Scattering cross section
Energy Technology Data Exchange (ETDEWEB)
Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil)
2011-10-01
In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90{sup o} (x=0.99 A{sup -1}). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number (Z{sub eff}) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Z{sub eff} of breast tissues, which are mainly related to the elemental composition of carbon (Z=6) and oxygen (Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.
International Nuclear Information System (INIS)
Bertolotti, M.; Sibilia, C.
1985-01-01
In this article the authors discuss a new approach for developing a coherent source of γ-rays. They offer a completely different scheme for development of the source that should overcome most of the problems encountered in ''classical γ-ray lasers,'' and in which the use of inverse Compton scattering of laser radiation onto a relativistic electron beam is made. This kind of interaction has been used to obtain γ-ray photons with good polarization and monochromaticity properties. The authors describe a new geometry of interaction which allows one to obtain coherent emission
Bi, Shuyun; Wang, Tianjiao; Zhao, Tingting; Wang, Yu
2014-06-01
A novel method with high sensitivity was designed for the determination of trace nucleic acids by using cationic surfactant cetylpyridinium chloride (CPC) and camellia sinensis (CS) as resonance Rayleigh light scattering (RLS) probes. It was found DNA could combine with CS and CPC in Tris-HCl buffer (pH = 7.4). Under optimum conditions, the RLS intensity of DNA can be enhanced by CPC-CS obviously at 294 nm, and the enhanced RLS intensity was directly proportional to DNA concentration in the range from 0.024 to 3.48 μg mL-1 with a good linear relationship (r = 0.9940). The limit of detection (LOD) was 1.49 ng mL-1 (S/N = 3). In addition, the effects of some interferences including K+, Na+, Mg2+, Zn2+, Cu2+, Ca2+ and glucose on the determination were studied. The developed RLS assay was successfully applied to three synthetic samples to measure DNA, the recovery was 94.7-106.3% and RSD was 0.58-3.33%.
Controlled light scattering in transparent polycrystalline ferroelectrics
International Nuclear Information System (INIS)
Vasilevskaya, A.S.; Grodnenskij, I.M.; Sonin, A.S.
1977-01-01
Scattering indicatrices, birefringence, attenuation factor and time characteristics of the light scattering effect have been investigated in a polycrystal solid solution of Pbsub(0.92)Lasub(0.08)(Zrsub(0.65)Tisub(0.35))Osub(3) with the crystallite dimension 4-5 μm. The measurements have been taken for longitudinal and transverse scattering effects in the visible range of spectrum in the temperature range 20-200 deg C. The time characteristics of the scattering effect have been found to be significantly different when a sample transfers from a thermally depolarized state to an electrically polarized one and from an electrically polarized state to an electrically depolarized one. The shape of the scattering indicatrices depends on the polarization state of a sample. The distribution of the scattered light intensity in the part of the indicatrix characterizing the fundamental scattering is satisfactorily described by the Rayleigh-Hans theory. The diameter of scattering centres responsible for the scattering has been determined to be 6-7 μm. The experimental data show that there are different types of scattering centres, in the material. The fundamental scattering is caused by centres arising irreversibly during initial polarization of the sample. The second type of centres is responsible for the controlled part of scattering during repolarization
Optimized suppression of coherent noise from seismic data using the Karhunen-Loeve transform
International Nuclear Information System (INIS)
Montagne, Raul; Vasconcelos, Giovani L.
2006-01-01
Signals obtained in land seismic surveys are usually contaminated with coherent noise, among which the ground roll (Rayleigh surface waves) is of major concern for it can severely degrade the quality of the information obtained from the seismic record. This paper presents an optimized filter based on the Karhunen-Loeve transform for processing seismic images contaminated with ground roll. In this method, the contaminated region of the seismic record, to be processed by the filter, is selected in such way as to correspond to the maximum of a properly defined coherence index. The main advantages of the method are that the ground roll is suppressed with negligible distortion of the remnant reflection signals and that the filtering procedure can be automated. The image processing technique described in this study should also be relevant for other applications where coherent structures embedded in a complex spatiotemporal pattern need to be identified in a more refined way. In particular, it is argued that the method is appropriate for processing optical coherence tomography images whose quality is often degraded by coherent noise (speckle)
International Nuclear Information System (INIS)
Rozanov, Vladimir V.; Vountas, Marco
2014-01-01
Rotational Raman scattering of solar light in Earth's atmosphere leads to the filling-in of Fraunhofer and telluric lines observed in the reflected spectrum. The phenomenological derivation of the inelastic radiative transfer equation including rotational Raman scattering is presented. The different forms of the approximate radiative transfer equation with first-order rotational Raman scattering terms are obtained employing the Cabannes, Rayleigh, and Cabannes–Rayleigh scattering models. The solution of these equations is considered in the framework of the discrete-ordinates method using rigorous and approximate approaches to derive particular integrals. An alternative forward-adjoint technique is suggested as well. A detailed description of the model including the exact spectral matching and a binning scheme that significantly speeds up the calculations is given. The considered solution techniques are implemented in the radiative transfer software package SCIATRAN and a specified benchmark setup is presented to enable readers to compare with own results transparently. -- Highlights: • We derived the radiative transfer equation accounting for rotational Raman scattering. • Different approximate radiative transfer approaches with first order scattering were used. • Rigorous and approximate approaches are shown to derive particular integrals. • An alternative forward-adjoint technique is suggested as well. • An additional spectral binning scheme which speeds up the calculations is presented
Coherent Raman Scattering Microscopy for Evaluation of Head and Neck Carcinoma.
Hoesli, Rebecca C; Orringer, Daniel A; McHugh, Jonathan B; Spector, Matthew E
2017-09-01
Objective We aim to describe a novel, label-free, real-time imaging technique, coherent Raman scattering (CRS) microscopy, for histopathological evaluation of head and neck cancer. We evaluated the ability of CRS microscopy to delineate between tumor and nonneoplastic tissue in tissue samples from patients with head and neck cancer. Study Design Prospective case series. Setting Tertiary care medical center. Subjects and Methods Patients eligible were surgical candidates with biopsy-proven, previously untreated head and neck carcinoma and were consented preoperatively for participation in this study. Tissue was collected from 50 patients, and after confirmation of tumor and normal specimens by hematoxylin and eosin (H&E), there were 42 tumor samples and 42 normal adjacent controls. Results There were 42 confirmed carcinoma specimens on H&E, and CRS microscopy identified 37 as carcinoma. Of the 42 normal specimens, CRS microscopy identified 40 as normal. This resulted in a sensitivity of 88.1% and specificity of 95.2% in distinguishing between neoplastic and nonneoplastic images. Conclusion CRS microscopy is a unique label-free imaging technique that can provide rapid, high-resolution images and can accurately determine the presence of head and neck carcinoma. This holds potential for implementation into standard practice, allowing frozen margin evaluation even at institutions without a histopathology laboratory.
Coherence properties of exciton-polariton OPO condensates in one and two dimensions
DEFF Research Database (Denmark)
Spano, R.; Cuadra, J.; Anton, C.
2012-01-01
We give an overview of the coherence properties of exciton-polariton condensates generated by optical parametric scattering. Different aspects of the first-order coherence (g((1))) have been investigated. The spatial coherence extension of a two-dimensional (2D) polariton system, below and at the...
Measurement of the magneto-optical correlation length in turbid media
Lenke, Ralf; Eisenmann, Christoph; Reinke, Daniel; Maret, Georg
2002-11-01
In multiple light scattering media, magnetic field induced circular birefringence (Faraday effect) influences interference effects such as speckle pattern or coherent backscattering. It was predicted that in the diffusive regime the relevant correlation length with respect to the Faraday rotation l*F differs, in general, from the transport mean free path l*. We have experimentally verified the prediction that the ratio l*F/l* equals 2 for Rayleigh scattering and decreases to 1 with increasing scatterer size. We also discuss the influence of the structure factor on l*F.
2013-01-01
This Handbook provides comprehensive coverage of laser and coherent-domain methods as applied to biomedicine, environmental monitoring, and materials science. Worldwide leaders in these fields describe the fundamentals of light interaction with random media and present an overview of basic research. The latest results on coherent and polarization properties of light scattered by random media, including tissues and blood, speckles formation in multiple scattering media, and other non-destructive interactions of coherent light with rough surfaces and tissues, allow the reader to understand the principles and applications of coherent diagnostic techniques. The expanded second edition has been thoroughly updated with particular emphasis on novel coherent-domain techniques and their applications in medicine and environmental science. Volume 1 describes state-of-the-art methods of coherent and polarization optical imaging, tomography and spectroscopy; diffusion wave spectroscopy; elastic, quasi-elastic and inelasti...
Berk, N. F.
2014-03-01
We present a general approach to analyzing elastic scattering for those situations where the incident beam is prepared as an incoherent ensemble of wave packets of a given arbitrary shape. Although wave packets, in general, are not stationary solutions of the Schrödinger equation, the analysis of elastic scattering data treats the scattering as a stationary-state problem. We thus must gate the wave packet, coherently distorting its shape in a manner consistent with the elastic condition. The resulting gated scattering amplitudes (e.g., reflection coefficients) thus are weighted coherent sums of the constituent plane-wave scattering amplitudes, with the weights determined by the shape of the incident wave packet as "filtered" by energy gating. We develop the gating formalism in general and apply it to the problem of neutron scattering from ruled gratings described by Majkrzak et al. in a companion paper. The required exact solution of the associated problem of plane-wave reflection from gratings also is derived.
On the Earth Microwave Background: Absorption and Scattering by the Atmosphere
Directory of Open Access Journals (Sweden)
Robitaille P.-M.
2007-07-01
Full Text Available The absorption and scattering of microwave radiation by the atmosphere of the Earth is considered under a steady state scenario. Using this approach, it is demonstrated that the microwave background could not have a cosmological origin. Scientific observations in the microwave region are explained by considering an oceanic source, combined with both Rayleigh and Mie scattering in the atmosphere in the absence of net absorption. Importantly, at high frequencies, Mie scattering occurs primarily with forward propagation. This helps to explain the lack of high frequency microwave background signals when radio antennae are positioned on the Earth’s surface.
Chromo-Rayleigh interactions of dark matter
International Nuclear Information System (INIS)
Bai, Yang; Osborne, James
2015-01-01
For a wide range of models, dark matter can interact with QCD gluons via chromo-Rayleigh interactions. We point out that the Large Hadron Collider (LHC), as a gluon machine, provides a superb probe of such interactions. In this paper, we introduce simplified models to UV-complete two effective dark matter chromo-Rayleigh interactions and identify the corresponding collider signatures, including four jets or a pair of di-jet resonances plus missing transverse energy. After performing collider studies for both the 8 TeV and 14 TeV LHC, we find that the LHC can be more sensitive to dark matter chromo-Rayleigh interactions than direct detection experiments and thus provides the best opportunity for future discovery of this class of models.
Neutron Scattering from 36Ar and 4He Films
DEFF Research Database (Denmark)
Carneiro, K.
1977-01-01
Scale factors for neutron diffraction and neutron inelastic scattering are presented for common adsorbates, and the feasibility of experiments is discussed together with the information gained by each type of experiment. Diffraction, coherent inelastic scattering, and incoherent scattering are tr...
Quantum scattering from classical field theory
International Nuclear Information System (INIS)
Gould, T.M.; Poppitz, E.R.
1995-01-01
We show that scattering amplitudes between initial wave packet states and certain coherent final states can be computed in a systematic weak coupling expansion about classical solutions satisfying initial-value conditions. The initial-value conditions are such as to make the solution of the classical field equations amenable to numerical methods. We propose a practical procedure for computing classical solutions which contribute to high energy two-particle scattering amplitudes. We consider in this regard the implications of a recent numerical simulation in classical SU(2) Yang-Mills theory for multiparticle scattering in quantum gauge theories and speculate on its generalization to electroweak theory. We also generalize our results to the case of complex trajectories and discuss the prospects for finding a solution to the resulting complex boundary value problem, which would allow the application of our method to any wave packet to coherent state transition. Finally, we discuss the relevance of these results to the issues of baryon number violation and multiparticle scattering at high energies. ((orig.))
On the interaction of Rayleigh surface waves with structures
International Nuclear Information System (INIS)
Simpson, I.C.
1976-12-01
A two-dimensional soil-structure interaction analysis is carried out for transient Rayleigh surface waves that are incident on a structure. The structure is modelled by a three-degree of freedom rigid basemat to which is attached a flexible superstructure, modelled by a single mass-spring system. The structural responses to a given Rayleigh wave train are compared with those that would have been obtained if the free-field acceleration-time history had been applied as a normally incident body wave. The results clearly exhibit the 'frequency filtering' effects of the rigid basemat on the incident Rayleigh waves. It is shown that, if seismic excitation of a structure is, in fact, due to Rayleigh surface waves, then an analysis assuming normally incident body waves can considerably over-estimate structural response, both at basemat level for horizontal and vertical oscillations of the superstructure. However, in the examples considered here, relatively large rocking effects were induced by the Rayleigh waves, thus giving maximum horizontal accelerations in the superstructure that were of comparable magnitude for Rayleigh and normally incident body waves. (author)
International Nuclear Information System (INIS)
Volkmer, Andreas
2005-01-01
For noninvasive characterization of chemical species or biological components within a complex heterogeneous system, their intrinsic molecular vibrational properties can be used in contrast mechanisms in optical microscopy. A series of recent advances have made coherent anti-Stokes Raman scattering (CARS) microscopy a powerful technique that allows vibrational imaging with high sensitivity, high spectral resolution and three-dimensional sectioning capability. In this review, we discuss theoretical and experimental aspects of CARS microscopy in a collinear excitation beam geometry. Particular attention is given to the underlying physical principles behind the new features of CARS signal generation under tight focusing conditions. We provide a brief overview of the instrumentation of CARS microscopy and its experimental characterization by means of imaging of model systems and live unstained cells. CARS microscopy offers the possibility of spatially resolved vibrational spectroscopy, providing chemical and physical structure information of molecular specimens on the sub-micrometre length scale. We review multiplex CARS microspectroscopy allowing fast acquisition of frequency-resolved CARS spectra, time-resolved CARS microspectroscopy recording ultrafast Raman free induction decays and CARS correlation spectroscopy probing dynamical processes with chemical selectivity. (topical review)
A Novel Simulator of Nonstationary Random MIMO Channels in Rayleigh Fading Scenarios
Directory of Open Access Journals (Sweden)
Qiuming Zhu
2016-01-01
Full Text Available For simulations of nonstationary multiple-input multiple-output (MIMO Rayleigh fading channels in time-variant scattering environments, a novel channel simulator is proposed based on the superposition of chirp signals. This new method has the advantages of low complexity and implementation simplicity as the sum of sinusoids (SOS method. In order to reproduce realistic time varying statistics for dynamic channels, an efficient parameter computation method is also proposed for updating the frequency parameters of employed chirp signals. Simulation results indicate that the proposed simulator is effective in generating nonstationary MIMO channels with close approximation of the time-variant statistical characteristics in accordance with the expected theoretical counterparts.
Quantitative contrast-enhanced optical coherence tomography
Energy Technology Data Exchange (ETDEWEB)
Winetraub, Yonatan; SoRelle, Elliott D. [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Biophysics Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Liba, Orly [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Zerda, Adam de la [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Biophysics Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States)
2016-01-11
We have developed a model to accurately quantify the signals produced by exogenous scattering agents used for contrast-enhanced Optical Coherence Tomography (OCT). This model predicts distinct concentration-dependent signal trends that arise from the underlying physics of OCT detection. Accordingly, we show that real scattering particles can be described as simplified ideal scatterers with modified scattering intensity and concentration. The relation between OCT signal and particle concentration is approximately linear at concentrations lower than 0.8 particle per imaging voxel. However, at higher concentrations, interference effects cause signal to increase with a square root dependence on the number of particles within a voxel. Finally, high particle concentrations cause enough light attenuation to saturate the detected signal. Predictions were validated by comparison with measured OCT signals from gold nanorods (GNRs) prepared in water at concentrations ranging over five orders of magnitude (50 fM to 5 nM). In addition, we validated that our model accurately predicts the signal responses of GNRs in highly heterogeneous scattering environments including whole blood and living animals. By enabling particle quantification, this work provides a valuable tool for current and future contrast-enhanced in vivo OCT studies. More generally, the model described herein may inform the interpretation of detected signals in modalities that rely on coherence-based detection or are susceptible to interference effects.
Coherence effects in atomic impact processes
International Nuclear Information System (INIS)
Blum, K.
1980-01-01
The author considers excitation of target atoms by projectile particles and the coincident detection of the scattered projectiles and the photons emitted in the subsequent decay by the target atoms. The observation is restricted to radiation emitted by those atoms only which 'scattered' the projectiles with a given energy in a given direction defined by the particle detector. Thus, a certain subensemble of atoms is selected in the experiment. The author reviews the theoretical scheme used for the description of the excited subensemble with the emphasis on the coherence properties. The author reviews developments of the Fano-Macek theory concerning the description of coherently excited states with different angular momenta and parities. A comprehensive expression for the angular distribution of the emitted radiation, including all possible interference terms is given. (Auth.)
Determination of coal ash content by the combined x-ray fluorescence and scattering spectrum
Mikhailov, I. F.; Baturin, A. A.; Mikhailov, A. I.; Borisova, S. S.; Fomina, L. P.
2018-02-01
An alternative method is proposed for the determination of the inorganic constituent mass fraction (ash) in solid fuel by the ratio of Compton and Rayleigh X-ray scattering peaks IC/IR subject to the iron fluorescence intensity. An original X-ray optical scheme with a Ti/Mo (or Sc/Cu) double-layer secondary radiator allows registration of the combined fluorescence-and-scattering spectrum at the specified scattering angle. An algorithm for linear calibration of the Compton-to-Rayleigh IC/IR ratio is proposed which uses standard samples with two certified characteristics: mass fractions of ash (Ad) and iron oxide (WFe2O3). Ash mass fractions have been determined for coals of different deposits in the wide range of Ad from 9.4% to 52.7% mass and WFe2O3 from 0.3% to 4.95% mass. Due to the high penetrability of the probing radiation with energy E > 17 keV, the sample preparation procedure is rather simplified in comparison with the traditional method of Ad determination by the sum of fluorescence intensities of all constituent elements.
Karlovets, Dmitry V; Serbo, Valeriy G
2017-10-27
Within a plane-wave approximation in scattering, an incoming wave packet's Wigner function stays positive everywhere, which obscures such purely quantum phenomena as nonlocality and entanglement. With the advent of the electron microscopes with subnanometer-sized beams, one can enter a genuinely quantum regime where the latter effects become only moderately attenuated. Here we show how to probe negative values of the Wigner function in scattering of a coherent superposition of two Gaussian packets with a nonvanishing impact parameter between them (a Schrödinger's cat state) by atomic targets. For hydrogen in the ground 1s state, a small parameter of the problem, a ratio a/σ_{⊥} of the Bohr radius a to the beam width σ_{⊥}, is no longer vanishing. We predict an azimuthal asymmetry of the scattered electrons, which is found to be up to 10%, and argue that it can be reliably detected. The production of beams with the not-everywhere-positive Wigner functions and the probing of such quantum effects can open new perspectives for noninvasive electron microscopy, quantum tomography, particle physics, and so forth.
Energy Technology Data Exchange (ETDEWEB)
Salathe, Marco; Rink, Thomas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)
2016-07-01
Due to ongoing progress in detector development and background suppression techniques first evidence of neutrino coherent scattering seems reachable in future experiments. In recent years efforts have been enhanced to detect this effect with germanium detectors. This work aims at summarizing and improving past studies on the potential of an experiment at a reactor site to a new level of accuracy by using the most recent neutrino spectra, knowledge gained in recent detector developments and in contrast to prior studies an energy-dependent quenching factor. The influence of the main parameters (background suppression, detector resolution and threshold, reactor spectra, different isotopes) of a germanium detector experiment is presented and the sensitivities regarding the main reaction channels are calculated. The results were obtained through two independent methods; an algebraic computation and a numerical simulation. Both methods reveal the most important experimental parameters and clarify the state of the art challenges that research has to meet in such an experiment.
International Nuclear Information System (INIS)
Breunig, Hans Georg; Weinigel, Martin; Bückle, Rainer; Kellner-Höfer, Marcel; König, Karsten; Lademann, Jürgen; Darvin, Maxim E; Sterry, Wolfram
2013-01-01
We report on in vivo coherent anti-Stokes Raman scattering spectroscopy (CARS), two-photon fluorescence and second-harmonic-generation imaging on human skin with a novel multimodal clinical CARS/multiphoton tomograph. CARS imaging is realized by a combination of femtosecond pulses with broadband continuum pulses generated by a photonic crystal fiber. The images reveal the microscopic distribution of (i) non-fluorescent lipids, (ii) endogenous fluorophores and (iii) the collagen network inside the human skin in vivo with subcellular resolution. Examples of healthy as well as cancer-affected skin are presented. (letter)
Breunig, Hans Georg; Weinigel, Martin; Bückle, Rainer; Kellner-Höfer, Marcel; Lademann, Jürgen; Darvin, Maxim E.; Sterry, Wolfram; König, Karsten
2013-02-01
We report on in vivo coherent anti-Stokes Raman scattering spectroscopy (CARS), two-photon fluorescence and second-harmonic-generation imaging on human skin with a novel multimodal clinical CARS/multiphoton tomograph. CARS imaging is realized by a combination of femtosecond pulses with broadband continuum pulses generated by a photonic crystal fiber. The images reveal the microscopic distribution of (i) non-fluorescent lipids, (ii) endogenous fluorophores and (iii) the collagen network inside the human skin in vivo with subcellular resolution. Examples of healthy as well as cancer-affected skin are presented.
Energy Technology Data Exchange (ETDEWEB)
Curry, J J, E-mail: jjcurry@nist.go [National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States)
2010-06-16
Coherent and incoherent scattering of x-rays during x-ray absorption imaging of high-intensity discharge lamps have been studied with Monte Carlo simulations developed specifically for this purpose. The Monte Carlo code is described and some initial results are discussed. Coherent scattering, because of its angular concentration in the forward direction, is found to be the most significant scattering mechanism. Incoherent scattering, although comparably strong, is not as significant because it results primarily in photons being scattered in the rearward direction and therefore out of the detector. Coherent scattering interferes with the detected absorption signal because the path of a scattered photon through the object to be imaged is unknown. Although scattering is usually a small effect, it can be significant in regions of high contrast. At the discharge/wall interface, as many as 50% of the detected photons are scattered photons. The effect of scattering on analysis of Hg distributions has not yet been quantified.
Observation of long phase-coherence length in epitaxial La-doped CdO thin films
Yun, Yu; Ma, Yang; Tao, Songsheng; Xing, Wenyu; Chen, Yangyang; Su, Tang; Yuan, Wei; Wei, Jian; Lin, Xi; Niu, Qian; Xie, X. C.; Han, Wei
2017-12-01
The search for long electron phase-coherence length, which is the length that an electron can keep its quantum wavelike properties, has attracted considerable interest in the last several decades. Here, we report the long phase-coherence length of ˜3.7 μm in La-doped CdO thin films at 2 K. Systematical investigations of the La doping and the temperature dependences of the electron mobility and the electron phase-coherence length reveal contrasting scattering mechanisms for these two physical properties. Furthermore, these results show that the oxygen vacancies could be the dominant scatters in CdO thin films that break the electron phase coherence, which would shed light on further investigation of phase-coherence properties in oxide materials.
Retrieving mesospheric water vapour from observations of volume scattering radiances
Directory of Open Access Journals (Sweden)
P. Vergados
2009-02-01
Full Text Available This study examines the possibility for a theoretical approach in the estimation of water vapour mixing ratios in the vicinity of polar mesospheric clouds (PMC using satellite observations of Volume Scattering Radiances (VSR obtained at the wavelength of 553 nm. The PMC scattering properties perturb the underlying molecular Rayleigh scattered solar radiance of the background atmosphere. As a result, the presence of PMC leads to an enhancement in the observed VSR at the altitude of the layer; the PMC VSRs are superimposed on the exponentially decreasing with height Rayleigh VSR, of the PMC-free atmosphere. The ratio between the observed and the Rayleigh VSR of the background atmosphere is used to simulate the environment in which the cloud layer is formed. In addition, a microphysical model of ice particle formation is employed to predict the PMC VSRs. The initial water vapour profile is perturbed until the modelled VSRs match the observed, at which point the corresponding temperature and water vapour profiles can be considered as a first approximation of those describing the atmosphere at the time of the observations. The role of temperature and water vapour in the cloud formation is examined by a number of sensitivity tests suggesting that the water vapour plays a dominant role in the cloud formation in agreement with experimental results. The estimated water vapour profiles are compared with independent observations to examine the model capability in the context of this study. The results obtained are in a good agreement at the peak of the PMC layer although the radiance rapidly decreases with height below the peak. This simplified scenario indicates that the technique employed can give a first approximation estimate of the water vapour mixing ratio, giving rise to the VSR observed in the presence of PMC.
Observation of Spontaneous Coherence in Bose-Einstein Condensate of Magnons
International Nuclear Information System (INIS)
Demidov, V. E.; Dzyapko, O.; Demokritov, S. O.; Melkov, G. A.; Slavin, A. N.
2008-01-01
The room-temperature dynamics of a magnon gas driven by short microwave pumping pulses is studied. An overpopulation of the lowest energy level of the system following the pumping is observed. Using the sensitivity of the Brillouin light scattering technique to the coherence degree of the scattering magnons we demonstrate the spontaneous emergence of coherence of the magnons at the lowest level, if their density exceeds a critical value. This finding is clear proof of the quantum nature of the observed phenomenon and direct evidence of Bose-Einstein condensation of magnons at room temperature
Quantum effets in nonresonant X-ray scattering
Energy Technology Data Exchange (ETDEWEB)
Slowik, Jan Malte
2015-11-15
Due to their versatile properties, X rays are a unique tool to investigate the structure and dynamics of matter. X-ray scattering is the fundamental principle of many imaging techniques. Examples are X-ray crystallography, which recently celebrated one hundred years and is currently the leading method in structure determination of proteins, as well as X-ray phase contrast imaging (PCI), which is an imaging technique with countless applications in biology, medicine, etc. The technological development of X-ray free electron lasers (XFEL) has brought X-ray imaging at the edge of a new scientific revolution. XFELs offer ultrashort X-ray pulses with unprecedented high X-ray fluence and excellent spatial coherence properties. These properties make them an outstanding radiation source for X-ray scattering experiments, providing ultrafast temporal resolution as well as atomic spatial resolution. However, the radiation-matter interaction in XFEL experiments also advances into a novel regime. This demands a sound theoretical fundament to describe and explore the new experimental possibilities. This dissertation is dedicated to the theoretical study of nonresonant X-ray scattering. As the first topic, I consider the near-field imaging by propagation based X-ray phase contrast imaging (PCI). I devise a novel theory of PCI, in which radiation and matter are quantized. Remarkably, the crucial interference term automatically excludes contributions from inelastic scattering. This explains the success of the classical description thus far. The second topic of the thesis is the X-ray imaging of coherent electronic motion, where quantum effects become particularly apparent. The electron density of coherent electronic wave packets - important in charge transfer and bond breaking - varies in time, typically on femto- or attosecond time scales. In the near future, XFELs are envisaged to provide attosecond X-ray pulses, opening the possibility for time-resolved ultrafast X-ray scattering
Quantum effets in nonresonant X-ray scattering
International Nuclear Information System (INIS)
Slowik, Jan Malte
2015-11-01
Due to their versatile properties, X rays are a unique tool to investigate the structure and dynamics of matter. X-ray scattering is the fundamental principle of many imaging techniques. Examples are X-ray crystallography, which recently celebrated one hundred years and is currently the leading method in structure determination of proteins, as well as X-ray phase contrast imaging (PCI), which is an imaging technique with countless applications in biology, medicine, etc. The technological development of X-ray free electron lasers (XFEL) has brought X-ray imaging at the edge of a new scientific revolution. XFELs offer ultrashort X-ray pulses with unprecedented high X-ray fluence and excellent spatial coherence properties. These properties make them an outstanding radiation source for X-ray scattering experiments, providing ultrafast temporal resolution as well as atomic spatial resolution. However, the radiation-matter interaction in XFEL experiments also advances into a novel regime. This demands a sound theoretical fundament to describe and explore the new experimental possibilities. This dissertation is dedicated to the theoretical study of nonresonant X-ray scattering. As the first topic, I consider the near-field imaging by propagation based X-ray phase contrast imaging (PCI). I devise a novel theory of PCI, in which radiation and matter are quantized. Remarkably, the crucial interference term automatically excludes contributions from inelastic scattering. This explains the success of the classical description thus far. The second topic of the thesis is the X-ray imaging of coherent electronic motion, where quantum effects become particularly apparent. The electron density of coherent electronic wave packets - important in charge transfer and bond breaking - varies in time, typically on femto- or attosecond time scales. In the near future, XFELs are envisaged to provide attosecond X-ray pulses, opening the possibility for time-resolved ultrafast X-ray scattering
International Nuclear Information System (INIS)
Dzyub, I.P.; Kochmarskij, V.Z.
1978-01-01
The specific features of coherent slow-neutron scattering in the neighbourhood of the quasilocal oscillation (QLO) frequency are investigated. By means of the calculation for a simple cubic crystal containing substitutional impurities it is demonstrated that the dispersion curves are discontinuous in the QLO frequency range. This dispersion curve discontinuity is associated with one-phonon peak in the neighbourhood of the QLO frequency. The results of neutron scattering experiments on Crsub(1-x)Wsub(x) and Cusub(1-x)Ausub(x) solutions are then considered from this standpoint. Selection rules for the phonon mass operator are established which allow to determine the symmetry of QLO which contribute to the broadening and shift of one-phonon peaks in the directions of high symmetry, depending on the transfer neutron-momentum orientation with respect to the principal axes of a crystal
Femtosecond coherent emission from GaAs bulk microcavities
Gurioli, Massimo; Bogani, Franco; Ceccherini, Simone; Colocci, Marcello; Beltram, Fabio; Sorba, Lucia
1999-02-01
The emission from a λ/2 GaAs bulk microcavity resonantly excited by femtosecond pulses has been characterized by using an interferometric correlation technique. It is found that the emission is dominated by the coherent signal due to light elastically scattered by disorder, and that scattering is predominantly originated from the lower polariton branch.
Kedar, Debbie; Arnon, Shlomi
2006-05-10
Optical wireless communication has been the subject of much research in recent years because of the increasing interest in laser satellite-ground links and urban optical wireless communication. The major sources of performance degradation have been identified as the spatial, angular, and temporal spread of the propagating beam when the propagation channel is multiscattering, resulting in reduced power reception and intersignal interference, as well as turbulence-induced scintillations and noise due to receiver circuitry and background illumination. However, coherence effects due to multipath interference caused by a scattering propagation channel do not appear to have been treated in detail in the scientific literature. We attempt a theoretical analysis of coherence interference in optical wireless communication through scattering channels and try to quantify the resultant performance degradation for different media. We conclude that coherence interference is discernible in optical wireless communication through scattering channels and is highly dependent on the microscopic nature of the propagation medium.
International Nuclear Information System (INIS)
Baltog, Ioan; Baibarac, Mihaela; Smaranda, Ion; Lefrant, Serge
2011-01-01
In this paper, we demonstrate that, by continuous single beam excitation, one can generate an abnormal anti-Stokes Raman emission (AASRE) whose properties are similar to a coherent anti-Stokes Raman scattering (CARS). The effect has been observed in materials which possess intrinsically nonlinear properties (LiNbO 3 and CdS), which have the electric susceptibility of third order different from zero, χ (3) ≠ 0, as well as in materials that become nonlinear under resonant optical excitation. In the latter case, we used poly-3,4-ethylendioxythiophene (PEDOT) in its undoped state deposited electrochemically on Au support. Raman studies corroborated with images of optical microscopy demonstrate that the production of AASRE is conditioned by the existence of a particular morphology of the sample able to ensure efficient transport of the light inside the sample through a multiple light scattering mechanism. In this context, it was found that LiNbO 3 and CdS in powder form as well as the PEDOT films layered on a rough Au substrate are suitable morphological forms. We explain AASRE as resulting from a wave-mixing mechanism of the incident laser light ω l with a Stokes-shifted Raman light ω S produced by a spontaneous Raman light scattering process, both strongly scattered inside the sample. As a CARS process, AASRE is conditioned by the achievement of phase-matching requirements, which makes the difference between the wave vectors of mixing light close to zero, Δk =/2k l - k S - k CARS /∼ 0. In condensed media, the small dispersion of the refractive index makes Δk ∼ 0 so that the formation of a favourable phase-matching geometry may be accomplished even at a crossing angle θ of travelling scattered light ω l and ω S . For tightly focused beams, the requirement of phase matching relaxes; it is no longer sensitive to the Raman shift, so that a wide intense anti-Stokes Raman spectrum is observed at an angle larger than the Stokes Raman spectrum.
DEFF Research Database (Denmark)
Langbein, Wolfgang Werner; Hvam, Jørn Märcher; Zimmermann, R.
1999-01-01
). This method determines the decays of intensity and coherence separately, thus distinguishing lifetime from pure dephasing. The secondary emission of excitons in semiconductor quantum wells is investigated. Here the combination of static disorder and inelastic scattering leads to a partially coherent emission....... The temperature dependence is well explained by phonon scattering....
Energy Technology Data Exchange (ETDEWEB)
Cruceru, I; Nicolescu, G [National Institute of Research and Development for Physics and Nuclear Engineering ' Horia - Hulubei' , PO Box MG - 6, 077125 Magurele (Romania); Duliu, O G [University of Bucharest, Department of Atomic and Nuclear Physics, PO Box MG-II, 077125 Magurele (Romania)
2008-11-01
Coherent scattering of neutrinos on high Debye temperature monocrystals represent an alternative to detect solar as well as other high flux neutrino sources such as nuclear reactors or nuclear tests. Therefore, the possibility of detecting neutrinos by using sapphire monocrystals is presented and analyzed. Preliminary evaluations showed that 1 MeV neutrinos with a fluency density of 10{sup 12} cm{sup -1} s{sup -1} could interact with a 100 g sapphire monocrystal with a force of about 10{sup -6} dyne, value measurable with a high sensitivity torsion balance. For this reason a torsion balance provided with 1 m length molybdenum or tungsten wire and an optical autocollimator able to measure small rotation angles of about 0.1 seconds of arc was designed, constructed and now is under preliminary tests. Both theoretical and practical implications of such kind of detector are presented and discussed.
The Terahertz Scattering Analysis of Rough Metallic and Dielectric Targets
Directory of Open Access Journals (Sweden)
Mou Yuan
2018-02-01
Full Text Available The terahertz scattering characteristics of metallic and dielectric rough targets is important for the investigation of the terahertz radar targets properties. According to the stationary phase theory and scalar approximation, if the radius of curvature at any point of the surface is much larger than the incident wavelength, and the wavelength is also much longer than the surface height function and Root-Mean-Square (RMS surface slope, the coherent and incoherent scattering Radar Cross Section (RCS of rough metallic and dielectric targets can be obtained. Based on the stationary phase approximation, the coherent RCS of rough conductors, smooth dielectric targets and rough dielectric targets can be easily deputed. The scattering characteristics of electrically large smooth Al and painted spheres are investigated in this paper, and the calculated RCS are verified by Mie scattering theory, the error is less than 0.1 dBm2. Based on lambert theory, it is demonstrated that the incoherent RCS is analyzed with better precision if the rough surfaces are divided into much more facets. In this paper, the coherent and incoherent scattering of rough Al and painted spheres are numerically observed, and the effects of surface roughness and materials are analyzed. The conclusions provide theoretical foundation for the terahertz scattering characteristics of electrically large rough targets.
Timeresolved Speckle Analysis: Probing the Coherence of Excitonic Secondary Emission
DEFF Research Database (Denmark)
Langbein, Wolfgang; Hvam, Jørn Märcher; Zimmermann, R.
1998-01-01
in semiconductor quantum wells is investigated. Here, a partial coherence results from an interplay between scattering due to static disorder and inelastic relaxation, without any influence of the radiative decay. The temperature dependence is well explained by dephasing due to phonon scattering....
CSIR Research Space (South Africa)
Jule, L
2015-07-01
Full Text Available We investigate light scattering by core–shell consisting of metal/dielectric composites considering spherical and cylindrical nanoinclusions, within the framework of the conventional Rayleigh approximation. By writing the electric potential...
Off-axis full-field swept-source optical coherence tomography using holographic refocusing
Hillmann, Dierck; Franke, Gesa; Hinkel, Laura; Bonin, Tim; Koch, Peter; Hüttmann, Gereon
2013-03-01
We demonstrate a full-field swept-source OCT using an off-axis geometry of the reference illumination. By using holographic refocusing techniques, a uniform lateral resolution is achieved over the measurement depth of approximately 80 Rayleigh lengths. Compared to a standard on-axis setup, artifacts and autocorrelation signals are suppressed and the measurement depth is doubled by resolving the complex conjugate ambiguity. Holographic refocusing was done efficiently by Fourier-domain resampling as demonstrated before in inverse scattering and holoscopy. It allowed to reconstruct a complete volume with about 10μm resolution over the complete measurement depth of more than 10mm. Off-axis full-field swept-source OCT enables high measurement depths, spanning many Rayleigh lengths with reduced artifacts.
International Nuclear Information System (INIS)
Wang Lifeng; Peng Jingdong; Liu Limin
2008-01-01
A new reversed-phase high performance liquid chromatography with resonance Rayleigh scattering detection (HPLC-RRS) was developed for simultaneous separation and determination of four tetracycline antibiotics (TCs). A good chromatographic separation among the compounds was achieved using a Synergi Fusion-RP column (150 mm x 4.6 mm; 4 μm) and a mobile phase consisting of methanol-acetonitrile-oxalic acid (5 mM) at the flow rate of 0.8 mL min -1 . Column temperature was 30 deg. C. The RRS signal was detected at λ ex = λ em = 370 nm. The recoveries of sample added standard ranged from 95.3% to 103.5%, and the relative standard deviation was below 2.79%. A detection limit of 2.12-5.12 μg mL -1 was reached and a linear range was found between peak height and concentration in the range of 10.36-518.0 μg mL -1 for oxytetracycline (OTC), 12.11-605.5 μg mL -1 for tetracycline (TC), 11.79-589.5 μg mL -1 for chlortetracycline (CTC) and 10.32-516.0 μg mL -1 for doxycycline (DC). The linear regression coefficients were all above 0.999. The method has been applied successfully to the determination of OTC, TC, CTC, DC in pharmaceutical formulations and in honey. The method was simple, rapid and showed a better linear relation and high repeatability
Energy Technology Data Exchange (ETDEWEB)
Lifeng, Wang [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Peng Jingdong [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)], E-mail: hxpengjd@swu.edu.cn; Limin, Liu [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)
2008-12-07
A new reversed-phase high performance liquid chromatography with resonance Rayleigh scattering detection (HPLC-RRS) was developed for simultaneous separation and determination of four tetracycline antibiotics (TCs). A good chromatographic separation among the compounds was achieved using a Synergi Fusion-RP column (150 mm x 4.6 mm; 4 {mu}m) and a mobile phase consisting of methanol-acetonitrile-oxalic acid (5 mM) at the flow rate of 0.8 mL min{sup -1}. Column temperature was 30 deg. C. The RRS signal was detected at {lambda}{sub ex} = {lambda}{sub em} = 370 nm. The recoveries of sample added standard ranged from 95.3% to 103.5%, and the relative standard deviation was below 2.79%. A detection limit of 2.12-5.12 {mu}g mL{sup -1} was reached and a linear range was found between peak height and concentration in the range of 10.36-518.0 {mu}g mL{sup -1} for oxytetracycline (OTC), 12.11-605.5 {mu}g mL{sup -1} for tetracycline (TC), 11.79-589.5 {mu}g mL{sup -1} for chlortetracycline (CTC) and 10.32-516.0 {mu}g mL{sup -1} for doxycycline (DC). The linear regression coefficients were all above 0.999. The method has been applied successfully to the determination of OTC, TC, CTC, DC in pharmaceutical formulations and in honey. The method was simple, rapid and showed a better linear relation and high repeatability.
Colour coherence in deep inelastic Compton scattering
Energy Technology Data Exchange (ETDEWEB)
Lebedev, A.I.; Vazdik, J.A. (Lebedev Physical Inst., Academy of Sciences, Moscow (USSR))
1992-01-01
MC simulation of Deep Inelastic Compton on proton - both QED and QCD - was performed on the basis of LUCIFER program for HERA energies. Charged hadron flow was calculated for string and independent fragmentation with different cuts on p{sub t} and x. It is shown that interjet colour coherence leads in the case of QCD Compton to the drag effects diminishing the hadron flow in the direction between quark jet and proton remnant jet. (orig.).
Colour coherence in deep inelastic Compton scattering
International Nuclear Information System (INIS)
Lebedev, A.I.; Vazdik, J.A.
1992-01-01
MC simulation of Deep Inelastic Compton on proton - both QED and QCD - was performed on the basis of LUCIFER program for HERA energies. Charged hadron flow was calculated for string and independent fragmentation with different cuts on p t and x. It is shown that interjet colour coherence leads in the case of QCD Compton to the drag effects diminishing the hadron flow in the direction between quark jet and proton remnant jet. (orig.)
Low angle X-ray scattering in biological tissues
International Nuclear Information System (INIS)
Lemos, Carla; Braz, Delson; Pinto, Nivia G.V.; Lima, Joao C.; Castro, Carlos R.F.; Filgueiras, R.A.; Mendonca, Leonardo; Lopes, Ricardo T.; Barroso, Regina C.
2007-01-01
Low-angle x-ray scatter (LAXS) for tissue characterization is based on the differences which result from the interference of photons coherently scattered from molecules of each sample. Biological samples (bone, blood and blood components) have been studied in recent years in our laboratory using powder diffractometer. The scattering information was obtained using a Shimadzu DRX 6000 diffractometer at the Nuclear Instrumentation Laboratory, Rio de Janeiro, Brazil. Unpolarized monoenergetic Kα radiation from Cu provided 8.04 keV photons. The measurements were made in reflection mode (θ-2θ geometry), with the sample stationary on a goniometer which rotates the sample and detector about an axis lying in the plane of the top of the sample holder. LAXS profiles from whole blood, plasma and formed elements were measured to investigate the nature of scattering from such lyophilized samples. The statistical analysis shows that the variation found for the characterization parameters is significant for whole blood considering the age. Gender was positively associated with the variation of the second peak position for the profiles obtained for formed elements. The correlation of the measured relative coherent intensity with the mineral content in the bone samples was investigated. These results suggest that the measurement of bone mineral content within trabecular bone can be performed by using quantitative coherent scattering information. (author)
Pohling, Christoph; Bocklitz, Thomas; Duarte, Alex S.; Emmanuello, Cinzia; Ishikawa, Mariana S.; Dietzeck, Benjamin; Buckup, Tiago; Uckermann, Ortrud; Schackert, Gabriele; Kirsch, Matthias; Schmitt, Michael; Popp, Jürgen; Motzkus, Marcus
2017-06-01
Multiplex coherent anti-Stokes Raman scattering (MCARS) microscopy was carried out to map a solid tumor in mouse brain tissue. The border between normal and tumor tissue was visualized using support vector machines (SVM) as a higher ranking type of data classification. Training data were collected separately in both tissue types, and the image contrast is based on class affiliation of the single spectra. Color coding in the image generated by SVM is then related to pathological information instead of single spectral intensities or spectral differences within the data set. The results show good agreement with the H&E stained reference and spontaneous Raman microscopy, proving the validity of the MCARS approach in combination with SVM.
International Nuclear Information System (INIS)
Gerlach, M.; Krumrey, M.; Cibik, L.; Mueller, P.; Ulm, G.
2009-01-01
Monte Carlo techniques are powerful tools to simulate the interaction of electromagnetic radiation with matter. One of the most widespread simulation program packages is Geant4. Almost all physical interaction processes can be included. However, it is not evident what accuracy can be obtained by a simulation. In this work, results of scattering experiments using monochromatized synchrotron radiation in the X-ray regime are quantitatively compared to the results of simulations using Geant4. Experiments were performed for various scattering foils made of different materials such as copper and gold. For energy-dispersive measurements of the scattered radiation, a cadmium telluride detector was used. The detector was fully characterized and calibrated with calculable undispersed as well as monochromatized synchrotron radiation. The obtained quantum efficiency and the response functions are in very good agreement with the corresponding Geant4 simulations. At the electron storage ring BESSY II the number of incident photons in the scattering experiments was measured with a photodiode that had been calibrated against a cryogenic radiometer, so that a direct comparison of scattering experiments with Monte Carlo simulations using Geant4 was possible. It was shown that Geant4 describes the photoeffect, including fluorescence as well as the Compton and Rayleigh scattering, with high accuracy, resulting in a deviation of typically less than 20%. Even polarization effects are widely covered by Geant4, and for Doppler broadening of Compton-scattered radiation the extension G4LECS can be included, but the fact that both features cannot be combined is a limitation. For most polarization-dependent simulations, good agreement with the experimental results was found, except for some orientations where Rayleigh scattering was overestimated in the simulation.
Gerlach, M.; Krumrey, M.; Cibik, L.; Müller, P.; Ulm, G.
2009-09-01
Monte Carlo techniques are powerful tools to simulate the interaction of electromagnetic radiation with matter. One of the most widespread simulation program packages is Geant4. Almost all physical interaction processes can be included. However, it is not evident what accuracy can be obtained by a simulation. In this work, results of scattering experiments using monochromatized synchrotron radiation in the X-ray regime are quantitatively compared to the results of simulations using Geant4. Experiments were performed for various scattering foils made of different materials such as copper and gold. For energy-dispersive measurements of the scattered radiation, a cadmium telluride detector was used. The detector was fully characterized and calibrated with calculable undispersed as well as monochromatized synchrotron radiation. The obtained quantum efficiency and the response functions are in very good agreement with the corresponding Geant4 simulations. At the electron storage ring BESSY II the number of incident photons in the scattering experiments was measured with a photodiode that had been calibrated against a cryogenic radiometer, so that a direct comparison of scattering experiments with Monte Carlo simulations using Geant4 was possible. It was shown that Geant4 describes the photoeffect, including fluorescence as well as the Compton and Rayleigh scattering, with high accuracy, resulting in a deviation of typically less than 20%. Even polarization effects are widely covered by Geant4, and for Doppler broadening of Compton-scattered radiation the extension G4LECS can be included, but the fact that both features cannot be combined is a limitation. For most polarization-dependent simulations, good agreement with the experimental results was found, except for some orientations where Rayleigh scattering was overestimated in the simulation.
Energy Technology Data Exchange (ETDEWEB)
Gerlach, M. [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Krumrey, M. [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany)], E-mail: Michael.Krumrey@ptb.de; Cibik, L.; Mueller, P.; Ulm, G. [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany)
2009-09-11
Monte Carlo techniques are powerful tools to simulate the interaction of electromagnetic radiation with matter. One of the most widespread simulation program packages is Geant4. Almost all physical interaction processes can be included. However, it is not evident what accuracy can be obtained by a simulation. In this work, results of scattering experiments using monochromatized synchrotron radiation in the X-ray regime are quantitatively compared to the results of simulations using Geant4. Experiments were performed for various scattering foils made of different materials such as copper and gold. For energy-dispersive measurements of the scattered radiation, a cadmium telluride detector was used. The detector was fully characterized and calibrated with calculable undispersed as well as monochromatized synchrotron radiation. The obtained quantum efficiency and the response functions are in very good agreement with the corresponding Geant4 simulations. At the electron storage ring BESSY II the number of incident photons in the scattering experiments was measured with a photodiode that had been calibrated against a cryogenic radiometer, so that a direct comparison of scattering experiments with Monte Carlo simulations using Geant4 was possible. It was shown that Geant4 describes the photoeffect, including fluorescence as well as the Compton and Rayleigh scattering, with high accuracy, resulting in a deviation of typically less than 20%. Even polarization effects are widely covered by Geant4, and for Doppler broadening of Compton-scattered radiation the extension G4LECS can be included, but the fact that both features cannot be combined is a limitation. For most polarization-dependent simulations, good agreement with the experimental results was found, except for some orientations where Rayleigh scattering was overestimated in the simulation.
Measurement of coherent $\\pi^{+}$ production in low energy neutrino-Carbon scattering
Abe, K.
2016-11-04
We report the first measurement of the flux-averaged cross section for charged current coherent $\\pi^{+}$ production on carbon for neutrino energies less than 1.5 GeV to a restricted final state phase space region in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso {\\it et al.}, the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. This results contradicts the null results reported by K2K and SciBooNE in a similar neutrino energy region.
Scattering with polarized neutrons
International Nuclear Information System (INIS)
Schweizer, J.
2007-01-01
In the history of neutron scattering, it was shown very soon that the use of polarized neutron beams brings much more information than usual scattering with unpolarized neutrons. We shall develop here the different scattering methods that imply polarized neutrons: 1) polarized beams without polarization analysis, the flipping ratio method; 2) polarized beams with a uniaxial polarization analysis; 3) polarized beams with a spherical polarization analysis. For all these scattering methods, we shall give examples of the physical problems which can been solved by these methods, particularly in the field of magnetism: investigation of complex magnetic structures, investigation of spin or magnetization densities in metals, insulators and molecular compounds, separation of magnetic and nuclear scattering, investigation of magnetic properties of liquids and amorphous materials and even, for non magnetic material, separation between coherent and incoherent scattering. (author)
Tang, Jianbo; Erdener, Sefik Evren; Li, Baoqiang; Fu, Buyin; Sakadzic, Sava; Carp, Stefan A.; Lee, Jonghwan; Boas, David A.
2018-02-01
Dynamic Light Scattering-Optical Coherence Tomography (DLS-OCT) takes the advantages of using DLS to measure particle flow and diffusion within an OCT resolution-constrained 3D volume, enabling the simultaneous measurements of absolute RBC velocity and diffusion coefficient with high spatial resolution. In this work, we applied DLS-OCT to measure both RBC velocity and the shear-induced diffusion coefficient within penetrating venules of the somatosensory cortex of anesthetized mice. Blood flow laminar profile measurements indicate a blunted laminar flow profile, and the degree of blunting decreases with increasing vessel diameter. The measured shear-induced diffusion coefficient was proportional to the flow shear rate with a magnitude of 0.1 to 0.5 × 10-6 mm2 . These results provide important experimental support for the recent theoretical explanation for why DCS is dominantly sensitive to RBC diffusive motion.
Effects of shock waves on Rayleigh-Taylor instability
International Nuclear Information System (INIS)
Zhang Yongtao; Shu Chiwang; Zhou Ye
2006-01-01
A numerical simulation of two-dimensional compressible Navier-Stokes equations using a high-order weighted essentially nonoscillatory finite difference shock capturing scheme is carried out in this paper, to study the effect of shock waves on the development of Rayleigh-Taylor instability. Shocks with different Mach numbers are introduced ahead or behind the Rayleigh-Taylor interface, and their effect on the transition to instability is demonstrated and compared. It is observed that shock waves can speed up the transition to instability for the Rayleigh-Taylor interface significantly. Stronger shocks are more effective in this speed-up process
Optical coherence refractometry.
Tomlins, Peter H; Woolliams, Peter; Hart, Christian; Beaumont, Andrew; Tedaldi, Matthew
2008-10-01
We introduce a novel approach to refractometry using a low coherence interferometer at multiple angles of incidence. We show that for plane parallel samples it is possible to measure their phase refractive index rather than the group index that is usually measured by interferometric methods. This is a significant development because it enables bulk refractive index measurement of scattering and soft samples, not relying on surface measurements that can be prone to error. Our technique is also noncontact and compatible with in situ refractive index measurements. Here, we demonstrate this new technique on a pure silica test piece and a highly scattering resin slab, comparing the results with standard critical angle refractometry.
Coherent active polarization control without loss
Ye, Yuqian; Hay, Darrick; Shi, Zhimin
2017-11-01
We propose a lossless active polarization control mechanism utilizing an anisotropic dielectric medium with two coherent inputs. Using scattering matrix analysis, we derive analytically the required optical properties of the anisotropic medium that can behave as a switchable polarizing beam splitter. We also show that such a designed anisotropic medium can produce linearly polarized light at any azimuthal direction through coherent control of two inputs with a specific polarization state. Furthermore, we present a straightforward design-on-demand procedure of a subwavelength-thick metastructure that can possess the desired optical anisotropy at a flexible working wavelength. Our lossless coherent polarization control technique may lead to fast, broadband and integrated polarization control elements for applications in imaging, spectroscopy, and telecommunication.
Model Accuracy Comparison for High Resolution Insar Coherence Statistics Over Urban Areas
Zhang, Yue; Fu, Kun; Sun, Xian; Xu, Guangluan; Wang, Hongqi
2016-06-01
The interferometric coherence map derived from the cross-correlation of two complex registered synthetic aperture radar (SAR) images is the reflection of imaged targets. In many applications, it can act as an independent information source, or give additional information complementary to the intensity image. Specially, the statistical properties of the coherence are of great importance in land cover classification, segmentation and change detection. However, compared to the amount of work on the statistical characters of SAR intensity, there are quite fewer researches on interferometric SAR (InSAR) coherence statistics. And to our knowledge, all of the existing work that focuses on InSAR coherence statistics, models the coherence with Gaussian distribution with no discrimination on data resolutions or scene types. But the properties of coherence may be different for different data resolutions and scene types. In this paper, we investigate on the coherence statistics for high resolution data over urban areas, by making a comparison of the accuracy of several typical statistical models. Four typical land classes including buildings, trees, shadow and roads are selected as the representatives of urban areas. Firstly, several regions are selected from the coherence map manually and labelled with their corresponding classes respectively. Then we try to model the statistics of the pixel coherence for each type of region, with different models including Gaussian, Rayleigh, Weibull, Beta and Nakagami. Finally, we evaluate the model accuracy for each type of region. The experiments on TanDEM-X data show that the Beta model has a better performance than other distributions.
MODEL ACCURACY COMPARISON FOR HIGH RESOLUTION INSAR COHERENCE STATISTICS OVER URBAN AREAS
Directory of Open Access Journals (Sweden)
Y. Zhang
2016-06-01
Full Text Available The interferometric coherence map derived from the cross-correlation of two complex registered synthetic aperture radar (SAR images is the reflection of imaged targets. In many applications, it can act as an independent information source, or give additional information complementary to the intensity image. Specially, the statistical properties of the coherence are of great importance in land cover classification, segmentation and change detection. However, compared to the amount of work on the statistical characters of SAR intensity, there are quite fewer researches on interferometric SAR (InSAR coherence statistics. And to our knowledge, all of the existing work that focuses on InSAR coherence statistics, models the coherence with Gaussian distribution with no discrimination on data resolutions or scene types. But the properties of coherence may be different for different data resolutions and scene types. In this paper, we investigate on the coherence statistics for high resolution data over urban areas, by making a comparison of the accuracy of several typical statistical models. Four typical land classes including buildings, trees, shadow and roads are selected as the representatives of urban areas. Firstly, several regions are selected from the coherence map manually and labelled with their corresponding classes respectively. Then we try to model the statistics of the pixel coherence for each type of region, with different models including Gaussian, Rayleigh, Weibull, Beta and Nakagami. Finally, we evaluate the model accuracy for each type of region. The experiments on TanDEM-X data show that the Beta model has a better performance than other distributions.
When holography meets coherent diffraction imaging.
Latychevskaia, Tatiana; Longchamp, Jean-Nicolas; Fink, Hans-Werner
2012-12-17
The phase problem is inherent to crystallographic, astronomical and optical imaging where only the intensity of the scattered signal is detected and the phase information is lost and must somehow be recovered to reconstruct the object's structure. Modern imaging techniques at the molecular scale rely on utilizing novel coherent light sources like X-ray free electron lasers for the ultimate goal of visualizing such objects as individual biomolecules rather than crystals. Here, unlike in the case of crystals where structures can be solved by model building and phase refinement, the phase distribution of the wave scattered by an individual molecule must directly be recovered. There are two well-known solutions to the phase problem: holography and coherent diffraction imaging (CDI). Both techniques have their pros and cons. In holography, the reconstruction of the scattered complex-valued object wave is directly provided by a well-defined reference wave that must cover the entire detector area which often is an experimental challenge. CDI provides the highest possible, only wavelength limited, resolution, but the phase recovery is an iterative process which requires some pre-defined information about the object and whose outcome is not always uniquely-defined. Moreover, the diffraction patterns must be recorded under oversampling conditions, a pre-requisite to be able to solve the phase problem. Here, we report how holography and CDI can be merged into one superior technique: holographic coherent diffraction imaging (HCDI). An inline hologram can be recorded by employing a modified CDI experimental scheme. We demonstrate that the amplitude of the Fourier transform of an inline hologram is related to the complex-valued visibility, thus providing information on both, the amplitude and the phase of the scattered wave in the plane of the diffraction pattern. With the phase information available, the condition of oversampling the diffraction patterns can be relaxed, and the
Adapting Controlled-source Coherence Analysis to Dense Array Data in Earthquake Seismology
Schwarz, B.; Sigloch, K.; Nissen-Meyer, T.
2017-12-01
Exploration seismology deals with highly coherent wave fields generated by repeatable controlled sources and recorded by dense receiver arrays, whose geometry is tailored to back-scattered energy normally neglected in earthquake seismology. Owing to these favorable conditions, stacking and coherence analysis are routinely employed to suppress incoherent noise and regularize the data, thereby strongly contributing to the success of subsequent processing steps, including migration for the imaging of back-scattering interfaces or waveform tomography for the inversion of velocity structure. Attempts have been made to utilize wave field coherence on the length scales of passive-source seismology, e.g. for the imaging of transition-zone discontinuities or the core-mantle-boundary using reflected precursors. Results are however often deteriorated due to the sparse station coverage and interference of faint back-scattered with transmitted phases. USArray sampled wave fields generated by earthquake sources at an unprecedented density and similar array deployments are ongoing or planned in Alaska, the Alps and Canada. This makes the local coherence of earthquake data an increasingly valuable resource to exploit.Building on the experience in controlled-source surveys, we aim to extend the well-established concept of beam-forming to the richer toolbox that is nowadays used in seismic exploration. We suggest adapted strategies for local data coherence analysis, where summation is performed with operators that extract the local slope and curvature of wave fronts emerging at the receiver array. Besides estimating wave front properties, we demonstrate that the inherent data summation can also be used to generate virtual station responses at intermediate locations where no actual deployment was performed. Owing to the fact that stacking acts as a directional filter, interfering coherent wave fields can be efficiently separated from each other by means of coherent subtraction. We
DEFF Research Database (Denmark)
Bekshaev, A. Ya; Angelsky, O. V.; Hanson, Steen Grüner
2012-01-01
between the forward- and backward-scattered momentum fluxes in the Rayleigh scattering regime appears due to the spin part of the internal energy flow in the incident beam. The transverse ponderomotive forces exerted on dielectric and conducting particles of different sizes are calculated and special......Based on the Mie theory and on the incident beam model via superposition of two plane waves, we analyze numerically the momentum flux of the field scattered by a spherical, nonmagnetic microparticle placed within the spatially inhomogeneous circularly polarized paraxial light beam. The asymmetry...
QUADRO: A SUPERVISED DIMENSION REDUCTION METHOD VIA RAYLEIGH QUOTIENT OPTIMIZATION.
Fan, Jianqing; Ke, Zheng Tracy; Liu, Han; Xia, Lucy
We propose a novel Rayleigh quotient based sparse quadratic dimension reduction method-named QUADRO (Quadratic Dimension Reduction via Rayleigh Optimization)-for analyzing high-dimensional data. Unlike in the linear setting where Rayleigh quotient optimization coincides with classification, these two problems are very different under nonlinear settings. In this paper, we clarify this difference and show that Rayleigh quotient optimization may be of independent scientific interests. One major challenge of Rayleigh quotient optimization is that the variance of quadratic statistics involves all fourth cross-moments of predictors, which are infeasible to compute for high-dimensional applications and may accumulate too many stochastic errors. This issue is resolved by considering a family of elliptical models. Moreover, for heavy-tail distributions, robust estimates of mean vectors and covariance matrices are employed to guarantee uniform convergence in estimating non-polynomially many parameters, even though only the fourth moments are assumed. Methodologically, QUADRO is based on elliptical models which allow us to formulate the Rayleigh quotient maximization as a convex optimization problem. Computationally, we propose an efficient linearized augmented Lagrangian method to solve the constrained optimization problem. Theoretically, we provide explicit rates of convergence in terms of Rayleigh quotient under both Gaussian and general elliptical models. Thorough numerical results on both synthetic and real datasets are also provided to back up our theoretical results.
Norm-Minimized Scattering Data from Intensity Spectra
Directory of Open Access Journals (Sweden)
Alexander Seel
2016-01-01
Full Text Available We apply the l1 minimizing technique of compressive sensing (CS to nonlinear quadratic observations. For the example of coherent X-ray scattering we provide the formulas for a Kalman filter approach to quadratic CS and show how to reconstruct the scattering data from their spatial intensity distribution.
Hiramatsu, Kotaro; Luo, Yizhi; Ideguchi, Takuro; Goda, Keisuke
2017-11-01
High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.
Directory of Open Access Journals (Sweden)
Jiaqi Wang
2017-09-01
Full Text Available Synchronized time-lens source is a novel method to generate synchronized optical pulses to mode-locked lasers, and has found widespread applications in coherent Raman scattering microscopy. Relative timing jitter between the mode-locked laser and the synchronized time-lens source is a key parameter for evaluating the synchronization performance of such synchronized laser systems. However, the origins of the relative timing jitter in such systems are not fully determined, which in turn prevents the experimental efforts to optimize the synchronization performance. Here, we demonstrate, through theoretical modeling and numerical simulation, that the photodetection could be one physical origin of the relative timing jitter. Comparison with relative timing jitter due to the intrinsic timing jitter of the mode-locked laser is also demonstrated, revealing different qualitative and quantitative behaviors. Based on the nature of this photodetection-induced timing jitter, we further propose several strategies to reduce the relative timing jitter. Our theoretical results will provide guidelines for optimizing synchronization performance in experiments.
Spontaneous Rayleigh-Brillouin scattering of ultraviolet light in nitrogen, dry air and moist air,
Witschas, B.; Vieitez, M.O.; Duijn, van E.-J.; Reitebuch, O.; Water, van de W.; Ubachs, W.
2010-01-01
Atmospheric lidar techniques for the measurement of wind, temperature, and optical properties of aerosols rely on the exact knowledge of the spectral line shape of the scattered laser light on molecules. We report on spontaneous Rayleigh–Brillouin scattering measurements in the ultraviolet at a
Low-angle X-ray scattering properties of irradiated spices
International Nuclear Information System (INIS)
Almeida, A.P.G.; Braz, D.; Barroso, R.C.; Lopes, R.T.
2007-01-01
The scattering of X-rays at low angles (LAXS) is a technique dominated by the coherent scattering process. One characteristic observation of low-angle coherent scattering is the so-called molecular interference effect, being characterized by the presence of one or more peaks in the forward direction of scattering. In the present study, LAXS profiles from five different spices are carefully measured in order to establish characteristic scattering signatures. Samples of Ceylon cinnamon, cumin, nutmeg, paprika and black pepper were bought in local market in Rio de Janeiro, Brazil. The LAXS patterns were obtained using a Shimadzu DRX 6000 diffractometer in reflection geometry. Coherent scattering patterns are measured for the samples for θ=5-35 o . The data were collected in 0.05 o increments every 3 s. In order to evaluate the possible molecular structure changes caused to the irradiation procedure, the signatures obtained for control (non-irradiated) spices were compared with spice samples irradiated with different doses varying from 3 to 40 kGy. The LAXS patterns of all samples were obtained after 30, 60, 90, 120 days to evaluate the effect of storage period. Scattering profiles from spices irradiated with different irradiation doses were obtained and the results compared. For each spice, there is no considerable deviation in shape in function of the irradiation dose. It indicates that the molecular structure of each analyzed spices is preserved considering the dose range chosen. The results show that the molecular structure was found to be stable during storage at the ambient temperature for up to 4 months
International Nuclear Information System (INIS)
Singh, Manpreet; Singh, Gurvinderjit; Singh, Bhajan; Sandhu, B.S.
2007-01-01
An inverse response matrix converts the observed pulse-height distribution of a NaI(Tl) scintillation detector to a photon spectrum. This also results in extraction of intensity distribution of multiply scattered events originating from interactions of 0.279 MeV photons with thick targets of soldering material. The observed pulse-height distributions are a composite of singly and multiply scattered events in addition to bremmstrahlung-and Rayleigh-scattered events. To evaluate the contribution of multiply scattered events, the spectrum of singly scattered events contributing to inelastic Compton peak is reconstructed analytically. The optimum thickness (saturation depth), at which the number of multiply scattered events saturates, has been measured. Monte Carlo calculations also support the present results
You, Sixian; Liu, Yuan; Arp, Zane; Zhao, Youbo; Chaney, Eric J.; Marjanovic, Marina; Boppart, Stephen A.
2017-07-01
Docosanol is an over-the-counter topical agent that has proved to be one of the most effective therapies for treating herpes simplex labialis. However, the mechanism by which docosanol suppresses lesion formation remains poorly understood. To elucidate its mechanism of action, we investigated the uptake of docosanol in living cells using coherent anti-Stokes Raman scattering microscopy. Based on direct visualization of the deuterated docosanol, we observed highly concentrated docosanol inside living cells 24 h after drug treatment. In addition, different spatial patterns of drug accumulation were observed in different cell lines. In keratinocytes, which are the targeted cells of docosanol, the drug molecules appeared to be docking at the periphery of the cell membrane. In contrast, the drug molecules in fibroblasts appeared to accumulate in densely packed punctate regions throughout the cytoplasm. These results suggest that this molecular imaging approach is suitable for the longitudinal tracking of drug molecules in living cells to identify cell-specific trafficking and may also have implications for elucidating the mechanism by which docosanol suppresses lesion formation.
Summary of coherent neutron scattering length
International Nuclear Information System (INIS)
Rauch, H.
1981-07-01
Experimental values of neutron-nuclei bound scattering lengths for some 354 isotopes and elements and the various spin-states are compiled in a uniform way together with their error bars as quoted in the original literature. Recommended values are also given. The definitions of the relevant quantities presented in the data tables and the basic principles of measurements are explained in the introductory chapters. The data is also available on a magnetic tape
Taori, Alok; Raghunath, Karnam; Jayaraman, Achuthan
We use combination of simultaneous measurements made with Rayleigh lidar and O2 airglow monitoring to improve lidar investigation capability to cover a higher altitude range. We feed instantaneous O2 airglow temperatures instead the model values at the top altitude for subsequent integration method of temperature retrieval using Rayleigh lidar back scattered signals. Using this method, errors in the lidar temperature estimates converges at higher altitudes indicating better altitude coverage compared to regular methods where model temperatures are used instead of real-time measurements. This improvement enables the measurements of short period waves at upper mesospheric altitudes (~90 km). With two case studies, we show that above 60 km the few short period wave amplitude drastically increases while, some of the short period wave show either damping or saturation. We claim that by using such combined measurements, a significant and cost effective progress can be made in the understanding of short period wave processes which are important for the coupling across the different atmospheric regions.
Precise tests of x-ray scattering theories in the Compton regime
International Nuclear Information System (INIS)
Dunford, R. W.; Gemmell, D. S.; Kanter, E. P.; Kraessig, B.; Southworth, S. H.; Young, L.
1999-01-01
The authors report two experiments intended to test the accuracy of state-of-the-art theoretical predictions for x-ray scattering from low-Z atoms. The first one deals with the differential x-ray scattering cross sections in Ne and He from 11-22 keV and the Ne Compton-to-Rayleigh scattering ratio in this energy range. It was found that, in order to be consistent with the experimental results, an accurate description at low Z must include nonlocal exchange, electron correlation, and dynamic effects. The second experiment concerns the ratio of helium double-to-single ionization for Compton scattering in the 8-28 keV energy range where published experimental and theoretical results so far fail to give a consistent picture. The progress of the experiment and the data analysis is reported
Optical Asymmetry and Nonlinear Light Scattering from Colloidal Gold Nanorods.
Lien, Miao-Bin; Kim, Ji-Young; Han, Myung-Geun; Chang, You-Chia; Chang, Yu-Chung; Ferguson, Heather J; Zhu, Yimei; Herzing, Andrew A; Schotland, John C; Kotov, Nicholas A; Norris, Theodore B
2017-06-27
A systematic study is presented of the intensity-dependent nonlinear light scattering spectra of gold nanorods under resonant excitation of the longitudinal surface plasmon resonance (SPR). The spectra exhibit features due to coherent second and third harmonic generation as well as a broadband feature that has been previously attributed to multiphoton photoluminescence arising primarily from interband optical transitions in the gold. A detailed study of the spectral dependence of the scaling of the scattered light with excitation intensity shows unexpected scaling behavior of the coherent signals, which is quantitatively accounted for by optically induced damping of the SPR mode through a Fermi liquid model of the electronic scattering. The broadband feature is shown to arise not from luminescence, but from scattering of the second-order longitudinal SPR mode with the electron gas, where efficient excitation of the second order mode arises from an optical asymmetry of the nanorod. The electronic-temperature-dependent plasmon damping and the Fermi-Dirac distribution together determine the intensity dependence of the broadband emission, and the structure-dependent absorption spectrum determines the spectral shape through the fluctuation-dissipation theorem. Hence a complete self-consistent picture of both coherent and incoherent light scattering is obtained with a single set of physical parameters.
Optical scattering lengths in large liquid-scintillator neutrino detectors
Energy Technology Data Exchange (ETDEWEB)
Wurm, M.; Feilitzsch, F. von; Goeger-Neff, M.; Hofmann, M.; Lewke, T.; Meindl, Q.; Moellenberg, R.; Oberauer, L.; Potzel, W.; Tippmann, M.; Todor, S.; Winter, J. [Physik-Department E15, Technische Universitaet Muenchen, James-Franck-Str., D-85748 Garching (Germany); Lachenmaier, T.; Traunsteiner, C. [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstr. 2, D-85748 Garching (Germany); Undagoitia, T. Marrodan [Physik-Department E15, Technische Universitaet Muenchen, James-Franck-Str., D-85748 Garching (Germany); Physik-Institut, Universitaet Zuerich, Winterthurstr. 189, CH-8057 Zuerich (Switzerland)
2010-05-15
For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents phenylxylylethane, linear alkylbenzene (LAB), and dodecane, which are under discussion for next-generation experiments such as SNO+ (Sudbury Neutrino Observatory), HanoHano, or LENA (Low Energy Neutrino Astronomy). Results comprise the wavelength range of 415-440 nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.
Optical scattering lengths in large liquid-scintillator neutrino detectors.
Wurm, M; von Feilitzsch, F; Göger-Neff, M; Hofmann, M; Lachenmaier, T; Lewke, T; Marrodán Undagoitia, T; Meindl, Q; Möllenberg, R; Oberauer, L; Potzel, W; Tippmann, M; Todor, S; Traunsteiner, C; Winter, J
2010-05-01
For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents phenylxylylethane, linear alkylbenzene (LAB), and dodecane, which are under discussion for next-generation experiments such as SNO+ (Sudbury Neutrino Observatory), HanoHano, or LENA (Low Energy Neutrino Astronomy). Results comprise the wavelength range of 415-440 nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.
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
LDRD final report on theory and exploration of quantum-dot optical nonlinearities and coherences
International Nuclear Information System (INIS)
Chow, Weng Wah
2008-01-01
A microscopic theory for investigating quantum-dot optical properties was developed. The theory incorporated advances on various aspects of quantum-dot physics developed at Sandia and elsewhere. Important components are a non-Markovian treatment of polarization dephasing due to carrier-carrier scattering (developed at Sandia) and a nonperturbative treatment within a polaron picture of the scattering of carriers by longitudinal-optical phonons (developed at Bremen University). A computer code was also developed that provides a detailed accounting of electronic structure influences and a consistent treatment of many-body effects, the latter via the incorporation of results from the microscopic theory. This code was used to explore quantum coherence physics in a quantum-dot system. The investigation furthers the understanding of the underlying differences between atomic quantum coherence and semiconductor quantum coherence, and helps improve the potential of using quantum coherences in quantum computing, coherent control and high-resolution spectroscopy
Chen, Fang; Peng, Jingdong; Liu, Shaopu; Peng, Huanjun; Pan, Ziyu; Bu, Lingli; Xiao, Huan; Zhang, Ruiwen
2017-04-01
A highly sensitive detection approach of resonance Rayleigh scattering spectra (RRS) is firstly applied to analyzing nootropic drugs including piracetam (PIR) and oxiracetam (OXI). In HCl-NaAc buffer solution (pH = 3.0), the OXI chelated with palladium (II) to form the chelate cation [Pd2·OXI]2 +, and then reacted with Congo red (CGR) by virtue of electrostatic attraction and hydrophobic force to form binary complex [Pd2·OXI]. CGR2, which could result in the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex = λem = 375 nm. This mixture complex not only has higher RRS, but also makes contribution to significant increase of fluorescence, and the same phenomena also were discovered in PIR. The enhanced RRS intensity is in proportion to the PIR and OXI concentration in the range of 0.03-3.0 μg mL- 1, and the detection limit (DL) of RRS method for PIR and OXI is 2.3 ng mL- 1 and 9.7 ng mL- 1. In addition, the DL of fluorescence method for PIR and OXI is 8.4 μg mL- 1 and 19.5 μg mL- 1. Obviously, the RRS is the highly sensitive method, and the recoveries of the two kinds of nootropic drugs were range from 100.4% to 101.8.0% with RSD (n = 5) from 1.1% to 3.1% by RRS method. This paper not only investigated the optimum conditions for detecting nootropics with using RRS method, but also focused on the reasons for enhancing RRS intensity and the reaction mechanism, which in order to firm and contract the resultant. Finally, The RRS method has been applied to detect nootropic drugs in human urine samples with satisfactory results. Fig. S2. The effect of ionic strength: Pd (II)-CGR system (curve a); Pd (II)-OXI-CGR system (curve b); Pd (II)-PIR- CGR system (curve c). Pd (II): 2.0 × 10- 4 mol L- 1; CGR: 1.0 × 10- 5 mol L- 1; OXI: 1.5 μg mL- 1; PIR: 2 μg mL- 1; NaCl: 1 mol L- 1. Fig. S3. The effect of time: Pd (II)-OXI-CGR system (curve a); Pd (II)-PIR-CGR system (curve b). Pd (II): 2.0 × 10- 4 mol L- 1; CGR: 1.0 × 10- 5 mol L- 1
High-frequency Rayleigh-wave method
Xia, J.; Miller, R.D.; Xu, Y.; Luo, Y.; Chen, C.; Liu, J.; Ivanov, J.; Zeng, C.
2009-01-01
High-frequency (???2 Hz) Rayleigh-wave data acquired with a multichannel recording system have been utilized to determine shear (S)-wave velocities in near-surface geophysics since the early 1980s. This overview article discusses the main research results of high-frequency surface-wave techniques achieved by research groups at the Kansas Geological Survey and China University of Geosciences in the last 15 years. The multichannel analysis of surface wave (MASW) method is a non-invasive acoustic approach to estimate near-surface S-wave velocity. The differences between MASW results and direct borehole measurements are approximately 15% or less and random. Studies show that simultaneous inversion with higher modes and the fundamental mode can increase model resolution and an investigation depth. The other important seismic property, quality factor (Q), can also be estimated with the MASW method by inverting attenuation coefficients of Rayleigh waves. An inverted model (S-wave velocity or Q) obtained using a damped least-squares method can be assessed by an optimal damping vector in a vicinity of the inverted model determined by an objective function, which is the trace of a weighted sum of model-resolution and model-covariance matrices. Current developments include modeling high-frequency Rayleigh-waves in near-surface media, which builds a foundation for shallow seismic or Rayleigh-wave inversion in the time-offset domain; imaging dispersive energy with high resolution in the frequency-velocity domain and possibly with data in an arbitrary acquisition geometry, which opens a door for 3D surface-wave techniques; and successfully separating surface-wave modes, which provides a valuable tool to perform S-wave velocity profiling with high-horizontal resolution. ?? China University of Geosciences (Wuhan) and Springer-Verlag GmbH 2009.
Light scattering by cubical particle in the WKB approximation
Directory of Open Access Journals (Sweden)
redouane lamsoudi
2017-11-01
Full Text Available In this work, we determined the analytical expressions of the form factor of a cubical particle in the WKB approximation. We adapted some variables (size parameter, refractive index, the scattering angle and found the form factor in the approximation of Rayleigh-Gans-Debye (RGD, Anomalous Diffraction (AD, and determined the efficiency factor of the extinction. Finally, to illustrate our formalism, we analyzed some numerical examples
Coherent active polarization control without loss
Directory of Open Access Journals (Sweden)
Yuqian Ye
2017-11-01
Full Text Available We propose a lossless active polarization control mechanism utilizing an anisotropic dielectric medium with two coherent inputs. Using scattering matrix analysis, we derive analytically the required optical properties of the anisotropic medium that can behave as a switchable polarizing beam splitter. We also show that such a designed anisotropic medium can produce linearly polarized light at any azimuthal direction through coherent control of two inputs with a specific polarization state. Furthermore, we present a straightforward design-on-demand procedure of a subwavelength-thick metastructure that can possess the desired optical anisotropy at a flexible working wavelength. Our lossless coherent polarization control technique may lead to fast, broadband and integrated polarization control elements for applications in imaging, spectroscopy, and telecommunication.
Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin
2016-04-18
The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.
Centrifugally Driven Rayleigh-Taylor Instability
Scase, Matthew; Hill, Richard
2017-11-01
The instability that develops at the interface between two fluids of differing density due to the rapid rotation of the system may be considered as a limit of high-rotation rate Rayleigh-Taylor instability. Previously the authors have considered the effect of rotation on a gravitationally dominated Rayleigh-Taylor instability and have shown that some growth modes of instability may be suppressed completely by the stabilizing effect of rotation (Phys. Rev. Fluids 2:024801, Sci. Rep. 5:11706). Here we consider the case of very high rotation rates and a negligible gravitational field. The initial condition is of a dense inner cylinder of fluid surrounded by a lighter layer of fluid. As the system is rotated about the generating axis of the cylinder, the dense inner fluid moves away from the axis and the familiar bubbles and spikes of Rayleigh-Taylor instability develop at the interface. The system may be thought of as a ``fluid-fluid centrifuge''. By developing a model based on an Orr-Sommerfeld equation, we consider the effects of viscosity, surface tension and interface diffusion on the growth rate and modes of instability. We show that under particular circumstances some modes may be stabilized. School of Mathematical Sciences.
International Nuclear Information System (INIS)
Otero, F A; Frontini, G L; Elicabe, G E
2011-01-01
An analytic model for the scattering of a spherical particle with spherical inclusions has been proposed under the RG approximation. The model can be used without limitations to describe an X-ray scattering experiment. However, for light scattering several conditions must be fulfilled. Based on this model an inverse methodology is proposed to estimate the radii of host particle and inclusions, the number of inclusions and the Distance Distribution Functions (DDF's) of the distances between inclusions and the distances between inclusions and the origin of coordinates. The methodology is numerically tested in a light scattering example in which the host particle is eliminated by matching the refractive indices of host particle and medium. The results obtained for this cluster particle are very satisfactory.
Generalized coherent states for the Coulomb problem in one dimension
International Nuclear Information System (INIS)
Nouri, S.
2002-01-01
A set of generalized coherent states for the one-dimensional Coulomb problem in coordinate representation is constructed. At first, we obtain a mapping for proper transformation of the one-dimensional Coulomb problem into a nonrotating four-dimensional isotropic harmonic oscillator in the hyperspherical space, and the generalized coherent states for the one-dimensional Coulomb problem is then obtained in exact closed form. This exactly soluble model can provide an adequate means for a quantum coherency description of the Coulomb problem in one dimension, sample for coherent aspects of the exciton model in one-dimension example in high-temperature superconductivity, semiconductors, and polymers. Also, it can be useful for investigating the coherent scattering of the Coulomb particles in one dimension
Simulating propagation of coherent light in random media using the Fredholm type integral equation
Kraszewski, Maciej; Pluciński, Jerzy
2017-06-01
Studying propagation of light in random scattering materials is important for both basic and applied research. Such studies often require usage of numerical method for simulating behavior of light beams in random media. However, if such simulations require consideration of coherence properties of light, they may become a complex numerical problems. There are well established methods for simulating multiple scattering of light (e.g. Radiative Transfer Theory and Monte Carlo methods) but they do not treat coherence properties of light directly. Some variations of these methods allows to predict behavior of coherent light but only for an averaged realization of the scattering medium. This limits their application in studying many physical phenomena connected to a specific distribution of scattering particles (e.g. laser speckle). In general, numerical simulation of coherent light propagation in a specific realization of random medium is a time- and memory-consuming problem. The goal of the presented research was to develop new efficient method for solving this problem. The method, presented in our earlier works, is based on solving the Fredholm type integral equation, which describes multiple light scattering process. This equation can be discretized and solved numerically using various algorithms e.g. by direct solving the corresponding linear equations system, as well as by using iterative or Monte Carlo solvers. Here we present recent development of this method including its comparison with well-known analytical results and a finite-difference type simulations. We also present extension of the method for problems of multiple scattering of a polarized light on large spherical particles that joins presented mathematical formalism with Mie theory.
Beamstop-based low-background ptychography to image weakly scattering objects
DEFF Research Database (Denmark)
Reinhardt, Juliane; Hoppe, Robert; Hofmann, Georg
2017-01-01
In recent years, X-ray ptychography has been established as a valuable tool for high-resolution imaging. Nevertheless, the spatial resolution and sensitivity in coherent diffraction imaging are limited by the signal that is detected over noise and over background scattering. Especially, coherent ...
Nano structured materials studied by coherent X-ray diffraction
International Nuclear Information System (INIS)
Gulden, Johannes
2013-03-01
Structure determination with X-rays in crystallography is a rapidly evolving field. Crystallographic methods for structure determination are based on the assumptions about the crystallinity of the sample. It is vital to understand the structure of possible defects in the crystal, because they can influence the structure determination. All conventional methods to characterize defects require a modelling through simulated data. No direct methods exist to image the core of defects in crystals. Here a new method is proposed, which will enable to visualize the individual scatterers around and at defects in crystals. The method is based on coherent X-ray scattering. X-rays are perfectly suited since they can penetrate thick samples and buried structures can be investigated Recent developments increased the coherent flux of X-Ray sources such as synchrotrons by orders of magnitude. As a result, the use of the coherent properties of X-rays is emerging as a new aspect of X-ray science. New upcoming and operating X-ray laser sources will accelerate this trend. One new method which has the capacity to recover structural information from the coherently scattered photons is Coherent X-ray Diffraction Imaging (CXDI). The main focus of this thesis is the investigation of the structure and the dynamics of colloidal crystals. Colloidal crystals can be used as a model for atomic crystals in order to understand the growth and defect structure. Despite the large interest in these structures, many details are still unknown.Therefore, it is vital to develop new approaches to measure the core of defects in colloidal crystals. After an introduction into the basics of the field of coherent X-ray scattering, this thesis introduces a novel method, Small Angle Bragg Coherent Diffractive Imaging, (SAB-CDI). This new measurement technique which besides the relevance to colloidal crystals can be applied to a large variety of nano structured materials. To verify the experimental possibilities the
Nano structured materials studied by coherent X-ray diffraction
Energy Technology Data Exchange (ETDEWEB)
Gulden, Johannes
2013-03-15
Structure determination with X-rays in crystallography is a rapidly evolving field. Crystallographic methods for structure determination are based on the assumptions about the crystallinity of the sample. It is vital to understand the structure of possible defects in the crystal, because they can influence the structure determination. All conventional methods to characterize defects require a modelling through simulated data. No direct methods exist to image the core of defects in crystals. Here a new method is proposed, which will enable to visualize the individual scatterers around and at defects in crystals. The method is based on coherent X-ray scattering. X-rays are perfectly suited since they can penetrate thick samples and buried structures can be investigated Recent developments increased the coherent flux of X-Ray sources such as synchrotrons by orders of magnitude. As a result, the use of the coherent properties of X-rays is emerging as a new aspect of X-ray science. New upcoming and operating X-ray laser sources will accelerate this trend. One new method which has the capacity to recover structural information from the coherently scattered photons is Coherent X-ray Diffraction Imaging (CXDI). The main focus of this thesis is the investigation of the structure and the dynamics of colloidal crystals. Colloidal crystals can be used as a model for atomic crystals in order to understand the growth and defect structure. Despite the large interest in these structures, many details are still unknown.Therefore, it is vital to develop new approaches to measure the core of defects in colloidal crystals. After an introduction into the basics of the field of coherent X-ray scattering, this thesis introduces a novel method, Small Angle Bragg Coherent Diffractive Imaging, (SAB-CDI). This new measurement technique which besides the relevance to colloidal crystals can be applied to a large variety of nano structured materials. To verify the experimental possibilities the
Techniques for depth-resolved imaging through turbid media including coherence-gated imaging
International Nuclear Information System (INIS)
Dunsby, C; French, P M W
2003-01-01
This article aims to review the panoply of techniques for realising optical imaging through turbid media such as biological tissue. It begins by briefly discussing optical scattering and outlines the various approaches that have been developed to image through scattering media including spatial filtering, time-gated imaging and coherence-based techniques. The discussion includes scanning and wide-field techniques and concentrates on techniques to discriminate in favour of unscattered ballistic light although imaging with scattered light is briefly reviewed. Wide-field coherence-gated imaging techniques are discussed in some detail with particular emphasis placed on techniques to achieve real-time high-resolution three-dimensional imaging including through turbid media, providing rapid whole-field acquisition and high depth and transverse spatial resolution images. (topical review)
Intraocular light scatter, reflections, fluorescence and absorption: what we see in the slit lamp.
van den Berg, Thomas J T P
2018-01-01
Much knowledge has been collected over the past 20 years about light scattering in the eye- in particular in the eye lens- and its visual effect, called straylight. It is the purpose of this review to discuss how these insights can be applied to understanding the slit lamp image. The slit lamp image mainly results from back scattering, whereas the effects on vision result mainly from forward scatter. Forward scatter originates from particles of about wavelength size distributed throughout the lens. Most of the slit lamp image originates from small particle scatter (Rayleigh scatter). For a population of middle aged lenses it will be shown that both these scatter components remove around 10% of the light from the direct beam. For slit lamp observation close to the reflection angles, zones of discontinuity (Wasserspalten) at anterior and posterior parts of the lens show up as rough surface reflections. All these light scatter effects increase with age, but the correlations with age, and also between the different components, are weak. For retro-illumination imaging it will be argued that the density or opacity seen in areas of cortical or posterior subcapsular cataract show up because of light scattering, not because of light loss. NOTES: (1) Light scatter must not be confused with aberrations. Light penetrating the eye is divided into two parts: a relatively small part is scattered, and removed from the direct beam. Most of the light is not scattered, but continues as the direct beam. This non-scattered part is the basis for functional imaging, but its quality is under the control of aberrations. Aberrations deflect light mainly over small angles (light scatter is important because of the straylight effects over large angles (>1°), causing problems like glare and hazy vision. (2) The slit lamp image in older lenses and nuclear cataract is strongly influenced by absorption. However, this effect is greatly exaggerated by the light path lengths concerned. This
Preliminary Examination of X-ray Scattering from Human Tissues
International Nuclear Information System (INIS)
Desouky, O.S.; Wilkinson, S.; Hall, C.; Rogers, K.; Round, A.
2008-01-01
Small Angle x-ray scattering (SAXS) and wide angle x-ray scattering (WAXS) patterns have been recorded from different human soft tissues using x-ray synchrotron radiation.Pathological breast, normal kidney and lung tissues show SAXS peaks at q-values equal to 0.291 nm -1 and 0.481 nm -1 (d 21.6 nm and d =13. nm) which are the 3 r d and 5 t h order of the well known axial D-spacing of collagen fibrils. The diffraction is particularly intense in the meridional direction indicating some febrile alignment. In contrast, the normal tissue of brain, liver and heart shows diffuse scatter.The wide-angle coherent scattering from normal human tissues of brain, liver, heart, lung, and kidney is typical of that for amorphous materials. The scatter of the healthy adipose breast tissue shows a sharp peak at momentum transfer 1.24 nm -1 (d= 0.417 nm). The data of the other tissues appears to consist of a broad scattering peak. The two scattering regimes succeed in differentiating between the two major components of breast tissue, collagen and adipose tissue. The results of this study suggest that the soft tissues may have scattering patterns that are characteristics for the particular tissue types and tissue disease state. These results indicate that it may be possible use the coherent scattering as a diagnostic tool
Energy Technology Data Exchange (ETDEWEB)
Tsytovich, Vadim, E-mail: tsytov@lpi.ru [A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilova str. 38, Moscow 119991 (Russian Federation); Max Planck Institute for Extraterrestrial Physics, Garching (Germany); Gusein-zade, Namik; Ignatov, Alexander [A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilova str. 38, Moscow 119991 (Russian Federation); Medicobiologic Faculty, Pirogov Russian National Research Medical University, Moscow (Russian Federation)
2015-07-15
Dust structuring is a natural and universal process in complex plasmas. The scattering of electromagnetic waves by dust structures is governed by the factor of coherency, i.e., the total number of coherent electrons in a single structure. In the present paper, we consider how the factor of coherency changes due to additional pulse electron heating and show that it obeys a hysteresis. After the end of the pulse heating, the scattering intensity differs substantially from that before heating. There are three necessary conditions for scattering hysteresis: first, the radiation wavelength should be larger than the pattern (structure) size; second, the total number of coherent electrons confined by the structure should be large; and third, the heating pulse duration should be shorter than the characteristic time of dust structure formation. We present the results of numerical calculations using existing models of self-consistent dust structures with either positively or negatively charged dust grains. It is shown that, depending on the grain charge and the ionization rate, two types of hysteresis are possible: one with a final increase of the scattering and the other with a final decrease of the scattering. It is suggested that the hysteresis of coherent scattering can be used as a tool in laboratory experiments and that it can be a basic mechanism explaining the observed hysteresis in radar scattering by noctilucent clouds during active experiments on electron heating in mesosphere.
International Nuclear Information System (INIS)
Nishino, Yoshinori; Kimura, Takashi; Suzuki, Akihiro; Joti, Yasumasa; Bessho, Yoshitaka
2017-01-01
X-ray free-electron lasers (XFELs) with femtosecond pulse duration offer an innovative solution to transcend the spatial resolution limitation in conventional X-ray imaging for biological samples and soft matters by clearing up the radiation damage problem using the “diffraction-before-destruction” strategy. Building on this strategy, the authors are developing a method to image solution sample under controlled environment, pulsed coherent X-ray solution scattering (PCXSS), using XFELs and phase retrieval algorithms in coherent diffractive imaging (CDI). This article describes the basics of PCXSS and examples of PCXSS measurement, for a living cell and self-assemblies of gold nanoparticles, performed by the authors using SACLA. An attempt toward the industrial application of PCXSS is also described. (author)
Coherent reflectivity using white synchrotron radiation
Energy Technology Data Exchange (ETDEWEB)
Panzner, Tobias; Sant, Tushar; Pietsch, Ullrich [Universitaet Siegen (Germany). Festkoerperphysik
2008-07-01
Using coherent white synchrotron radiation in the hard X-ray region for reflectivity experiments one have access to sample properties on a nanometer scale in principle. To extract the wanted information from the performed measurements so called phase retrieval algorithms are necessary. The authors developed a straight forward simulation program based on a spatial limited atomic flat surface to evaluate the influence of different parameters on the coherent scattered signal in the detector plane. These simulations can explain some interesting features of the measurements and shows unexpected results for the influence of the so called illumination function.
Laser light scattering in a laser-induced argon plasma: Investigations of the shock wave
Energy Technology Data Exchange (ETDEWEB)
Pokrzywka, B. [Obserwatorium Astronomiczne na Suhorze, Uniwersytet Pedagogiczny, ulica Podchorazych 2, 30-084 Krakow (Poland); Mendys, A., E-mail: agata.mendys@uj.edu.pl [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Dzierzega, K.; Grabiec, M. [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Pellerin, S. [GREMI, site de Bourges, Universite d' Orleans, CNRS, rue Gaston Berger BP 4043, 18028 Bourges (France)
2012-08-15
Shock wave produced by a laser induced spark in argon at atmospheric pressure was examined using Rayleigh and Thomson scattering. The spark was generated by focusing a laser pulse from the second harmonic ({lambda} = 532 nm) of a nanosecond Nd:YAG laser using an 80 mm focal length lens, with a fluence of 2 kJ{center_dot}cm{sup -2}. Images of the spark emission were recorded for times between 30 ns and 100 {mu}s after the laser pulse in order to characterize its spatial evolution. The position of the shock wave at several instants of its evolution and for several plasma regions was determined from the Rayleigh-scattered light of another nanosecond Nd:YAG laser (532 nm, 40 J{center_dot}cm{sup -2} fluence). Simultaneously, Thomson scattering technique was applied to determine the electron density and temperature in the hot plasma core. Attempts were made to describe the temporal evolution of the shock wave within a self-similar model, both by the simple Sedov-Taylor formula as well as its extension deduced by de Izarra. The temporal radial evolution of the shock position is similar to that obtained within theory taking into account the counter pressure of the ambient gas. Density profiles just behind the shock front are in qualitative agreement with those obtained by numerically solving the Euler equations for instantaneous explosion at a point with counter pressure. - Highlights: Black-Right-Pointing-Pointer We investigated shock wave evolution by Rayleigh scattering method. Black-Right-Pointing-Pointer 2D map of shockwave position for several times after plasma generation is presented. Black-Right-Pointing-Pointer Shock wave evolution is not satisfactorily described within self-similar models. Black-Right-Pointing-Pointer Evolution of shock position similar to theory taking into account counter pressure. Black-Right-Pointing-Pointer Density profile behind the shock similar to numerical solution of Euler equations.
Energy Technology Data Exchange (ETDEWEB)
Grech, M
2007-06-15
Inertial confinement fusion by laser requires smoothed laser beam with well-controlled coherence properties. Such beams are made of many randomly distributed intensity maxima: the so-called speckles. As the laser beam propagates through plasma its temporal and spatial coherence can be reduced. This phenomenon is called plasma induced smoothing. For high laser intensities, instabilities developing independently inside the speckles are responsible for the coherence loss. At lower intensities, only collective effects, involving many speckles, can lead to induced smoothing. This thesis is a theoretical, numerical and experimental study of these mechanisms. Accounting for the partially incoherent behavior of the laser beams requires the use of statistical description of the laser-plasma interaction. A model is developed for the multiple scattering of the laser light on the self-induced density perturbations that is responsible for a spreading of the temporal and spatial spectra of the transmitted light. It also serves as a strong seed for the instability of forward stimulated Brillouin scattering that induces both, angular spreading and red-shift of the transmitted light. A statistical model is developed for this instability. A criterion is obtained that gives a laser power (below the critical power for filamentation) above which the instability growth is important. Numerical simulations with the interaction code PARAX and an experiment performed on the ALISE laser facility confirm the importance of these forward scattering mechanisms in the modification of the laser coherence properties. (author)
Audio frequency in vivo optical coherence elastography
Adie, Steven G.; Kennedy, Brendan F.; Armstrong, Julian J.; Alexandrov, Sergey A.; Sampson, David D.
2009-05-01
We present a new approach to optical coherence elastography (OCE), which probes the local elastic properties of tissue by using optical coherence tomography to measure the effect of an applied stimulus in the audio frequency range. We describe the approach, based on analysis of the Bessel frequency spectrum of the interferometric signal detected from scatterers undergoing periodic motion in response to an applied stimulus. We present quantitative results of sub-micron excitation at 820 Hz in a layered phantom and the first such measurements in human skin in vivo.
Audio frequency in vivo optical coherence elastography
International Nuclear Information System (INIS)
Adie, Steven G; Kennedy, Brendan F; Armstrong, Julian J; Alexandrov, Sergey A; Sampson, David D
2009-01-01
We present a new approach to optical coherence elastography (OCE), which probes the local elastic properties of tissue by using optical coherence tomography to measure the effect of an applied stimulus in the audio frequency range. We describe the approach, based on analysis of the Bessel frequency spectrum of the interferometric signal detected from scatterers undergoing periodic motion in response to an applied stimulus. We present quantitative results of sub-micron excitation at 820 Hz in a layered phantom and the first such measurements in human skin in vivo.
Resonantly scattering crystals and surfaces
International Nuclear Information System (INIS)
Gunn, J.M.F.; Mahon, P.J.
1990-12-01
We examine coherence effects from forming a crystal of resonant scatterers by generalising the Fano model for autoionising resonances in electron scattering from atoms to a lattice of such scatterers. (We have in mind the case of neutron scattering from nuclei.) We solve this problem to yield two branches to the dispersion relation for the neutron in general and three when the resonance coincides with a Brillouin Zone boundary. The 'width' of the resonance is enhanced over the isolated nucleus, the best candidate for observation being the 2eV 185 Re resonance near the Bragg condition. We use these results to calculate the reflection coefficient from a surface, revealing total external reflection near resonance. We discuss experimental feasibility in both the neutron and electron cases. (author)
Differential on-on keying: A robust non-coherent digital modulation scheme
Kaddoum, Georges
2015-05-01
A robust digital modulation scheme, called differential on-on keying (DOOK), is presented in this paper which outperforms the conventional on-off keying (OOK). In this scheme, a sinusoidal signal is transmitted during the first half of the bit duration while a replica or an inverted version of the sinusoidal signal is transmitted during the second half for logic one or logic zero, respectively. Non-coherent receiver correlates the two halves of the received signal over half bit duration to construct a decision variable. Bit error performance is analyzed over AWGN and Rayleigh fading channels and compared to the conventional OOK.
Differential on-on keying: A robust non-coherent digital modulation scheme
Kaddoum, Georges; Ahmed, Mohammed F. A.; Al-Naffouri, Tareq Y.
2015-01-01
A robust digital modulation scheme, called differential on-on keying (DOOK), is presented in this paper which outperforms the conventional on-off keying (OOK). In this scheme, a sinusoidal signal is transmitted during the first half of the bit duration while a replica or an inverted version of the sinusoidal signal is transmitted during the second half for logic one or logic zero, respectively. Non-coherent receiver correlates the two halves of the received signal over half bit duration to construct a decision variable. Bit error performance is analyzed over AWGN and Rayleigh fading channels and compared to the conventional OOK.
Weng, Sheng; Xu, Xiaoyun; Li, Jiasong; Wong, Stephen T. C.
2017-10-01
Lung cancer is the most prevalent type of cancer and the leading cause of cancer-related deaths worldwide. Coherent anti-Stokes Raman scattering (CARS) is capable of providing cellular-level images and resolving pathologically related features on human lung tissues. However, conventional means of analyzing CARS images requires extensive image processing, feature engineering, and human intervention. This study demonstrates the feasibility of applying a deep learning algorithm to automatically differentiate normal and cancerous lung tissue images acquired by CARS. We leverage the features learned by pretrained deep neural networks and retrain the model using CARS images as the input. We achieve 89.2% accuracy in classifying normal, small-cell carcinoma, adenocarcinoma, and squamous cell carcinoma lung images. This computational method is a step toward on-the-spot diagnosis of lung cancer and can be further strengthened by the efforts aimed at miniaturizing the CARS technique for fiber-based microendoscopic imaging.
Calculation of electron-helium scattering
International Nuclear Information System (INIS)
Fursa, D.V.; Bray, I.
1994-11-01
We present the Convergent Close-Coupling (CCC) theory for the calculation of electron-helium scattering. We demonstrate its applicability at a range of projectile energies of 1.5 to 500 eV to scattering from the ground state to n ≤3 states. Excellent agreement with experiment is obtained with the available differential, integrated, ionization, and total cross sections, as well as with the electron-impact coherence parameters up to and including the 3 3 D state excitation. Comparison with other theories demonstrates that the CCC theory is the only general reliable method for the calculation of electron helium scattering. (authors). 66 refs., 2 tabs., 24 figs
International Nuclear Information System (INIS)
Nazikian, R.
1990-07-01
In the limit of the first Born approximation for a partially coherent secondary source, consisting of a spatially random plasma illuminated by a coherent plane wave, it is shown that the spectral coherence of the scattered radiation as measured on an arbitrary plane beyond the scatterer conveys information on the three dimensional intensity distribution of the random source. By defining a new two point statistical measure of the random field, closely related to the cross spectral density, we show that the fluctuation amplitude of the random source along the direction of the incident plane wave may by recovered from the measurement of the scattered radiation. The application of cross spectral techniques to fluctuation studies on tokamaks is considered. 7 refs
Rayleigh Waves in a Rotating Orthotropic Micropolar Elastic Solid Half-Space
Directory of Open Access Journals (Sweden)
Baljeet Singh
2013-01-01
Full Text Available A problem on Rayleigh wave in a rotating half-space of an orthotropic micropolar material is considered. The governing equations are solved for surface wave solutions in the half space of the material. These solutions satisfy the boundary conditions at free surface of the half-space to obtain the frequency equation of the Rayleigh wave. For numerical purpose, the frequency equation is approximated. The nondimensional speed of Rayleigh wave is computed and shown graphically versus nondimensional frequency and rotation-frequency ratio for both orthotropic micropolar elastic and isotropic micropolar elastic cases. The numerical results show the effects of rotation, orthotropy, and nondimensional frequency on the nondimensional speed of the Rayleigh wave.
NEUTRON-SCATTERING STUDY OF DCN
DEFF Research Database (Denmark)
Mackenzie, Gordon A.; Pawley, G. S.
1979-01-01
Phonons in deuterium cyanide have been measured by neutron coherent inelastic scattering. The main subject of study was the transverse acoustic mode in the (110) direction polarised along (110) which is associated with the first-order structural phase transition at 160K. Measurements have shown...
Guo, L.; Bhattacharjee, A.; Huang, Y. M.; Innes, D.
2014-12-01
Supra-arcade downflows (hereafter referred to as SADs) are low-emission, elongated, finger-like features usually observed in active-region coronae above post-eruption flare arcades. Observations exhibit downward moving SADs intertwined with bright, upward moving spikes. Whereas SADs are dark voids, spikes are brighter, denser structures. Although SADs have been observed for decades, the mechanism for formation of SADs remains an open issue. Using high-Lundquist-number three-dimensional resistive MHD simulations, we demonstrate that secondary Rayleigh-Taylor type instabilities develop in the downstream region of a reconnecting current sheet. The instability results in the formation of low-density coherent structures that resemble SADs, intertwined with high-density structures that appear to be spike-like. Using SDO/AIA images, we highlight features that have been previously unexplained, such as the splitting of SADs at their heads, but are a natural consequence of instabilities above the arcade. Comparison with siumlations suggest that secondary Rayleigh-Taylor type instabilities in the exhaust of reconnecting current sheets provide a plausible mechanism for observed SADs and spikes. Although the plasma conditions are vastly different, analogous phenomena also occur in the Earth's magnetotail during reconnection.
Preliminary study of Rayleigh-Taylor instability in wire-array Z-pinch
International Nuclear Information System (INIS)
He Kaihui; Feng Kaiming; Li Qiang; Gao Chunming
2000-01-01
It is important to research into the MHD Rayleigh-Taylor instability developed in Z-pinch implosion. A snowplough model of the single wire Z-pinch is presented. The perturbation amplitude of Rayleigh-Taylor instability in the wire-array Z-pinch is analyzed quantitatively. Sheared axial flow is put forward to mitigate and reduce the Rayleigh-Taylor instability. And other approaches used to mitigate MHD instability in such a super-fast process are explored
Attractors of the periodically forced Rayleigh system
Directory of Open Access Journals (Sweden)
Petre Bazavan
2011-07-01
Full Text Available The autonomous second order nonlinear ordinary differential equation(ODE introduced in 1883 by Lord Rayleigh, is the equation whichappears to be the closest to the ODE of the harmonic oscillator withdumping.In this paper we present a numerical study of the periodic andchaotic attractors in the dynamical system associated with the generalized Rayleigh equation. Transition between periodic and quasiperiodic motion is also studied. Numerical results describe the system dynamics changes (in particular bifurcations, when the forcing frequency is varied and thus, periodic, quasiperiodic or chaotic behaviour regions are predicted.
Coherent beam control through inhomogeneous media in multi-photon microscopy
Paudel, Hari Prasad
Multi-photon fluorescence microscopy has become a primary tool for high-resolution deep tissue imaging because of its sensitivity to ballistic excitation photons in comparison to scattered excitation photons. The imaging depth of multi-photon microscopes in tissue imaging is limited primarily by background fluorescence that is generated by scattered light due to the random fluctuations in refractive index inside the media, and by reduced intensity in the ballistic focal volume due to aberrations within the tissue and at its interface. We built two multi-photon adaptive optics (AO) correction systems, one for combating scattering and aberration problems, and another for compensating interface aberrations. For scattering correction a MEMS segmented deformable mirror (SDM) was inserted at a plane conjugate to the objective back-pupil plane. The SDM can pre-compensate for light scattering by coherent combination of the scattered light to make an apparent focus even at a depths where negligible ballistic light remains (i.e. ballistic limit). This problem was approached by investigating the spatial and temporal focusing characteristics of a broad-band light source through strongly scattering media. A new model was developed for coherent focus enhancement through or inside the strongly media based on the initial speckle contrast. A layer of fluorescent beads under a mouse skull was imaged using an iterative coherent beam control method in the prototype two-photon microscope to demonstrate the technique. We also adapted an AO correction system to an existing in three-photon microscope in a collaborator lab at Cornell University. In the second AO correction approach a continuous deformable mirror (CDM) is placed at a plane conjugate to the plane of an interface aberration. We demonstrated that this "Conjugate AO" technique yields a large field-of-view (FOV) advantage in comparison to Pupil AO. Further, we showed that the extended FOV in conjugate AO is maintained over a
Scattering of light by nonspherical particles
International Nuclear Information System (INIS)
Coulson, K.L.
1985-12-01
Methods of computing scattering by non-spherical particles are reviewed for the Mie theory, the Rayleigh-Gans approximation, the geometric optics method, the extended boundary condition method, the anamalous diffraction, the suppression of resonances, the statistical approach, the expansion of vector wave equations in spheroidal coordinates, and the semi-emperical theory of Pollack and Cuzzi. The results of computations for nonspherical particles are compared for prolate and oblate spheroids, homogeneous sphere with holes, rough particles made of stacked cylinders, irregular particles of various shapes, and particles of carbonaceous smokes. Conclusions are presented in the context of nuclear winter