Pion nucleus scattering lengths
International Nuclear Information System (INIS)
Huang, W.T.; Levinson, C.A.; Banerjee, M.K.
1971-09-01
Soft pion theory and the Fubini-Furlan mass dispersion relations have been used to analyze the pion nucleon scattering lengths and obtain a value for the sigma commutator term. With this value and using the same principles, scattering lengths have been predicted for nuclei with mass number ranging from 6 to 23. Agreement with experiment is very good. For those who believe in the Gell-Mann-Levy sigma model, the evaluation of the commutator yields the value 0.26(m/sub σ//m/sub π/) 2 for the sigma nucleon coupling constant. The large dispersive corrections for the isosymmetric case implies that the basic idea behind many of the soft pion calculations, namely, slow variation of matrix elements from the soft pion limit to the physical pion mass, is not correct. 11 refs., 1 fig., 3 tabs
International Nuclear Information System (INIS)
Hjelm, R.P.; Wampler, W.; Gerspacher, M.
1994-01-01
As part of our work on the, structure of composite materials we have been exploring the use of small-angle neutron scattering using the method of contrast variation to dissect the component form, structure and distribution. This approach has resulted in a new look at very old problem reinforcement of elastomers by carbon black. Using this approach we studied an experimental high surface area (HSA) carbon black and a gel of ''HSA-bound'' rubber in cyclohexane/deuterocyclohexane mixtures. HSA in cyclohexane is found to be short rodlike particle aggregates. The aggregates have a shell-core structure with a high density graphitic outer shell and an inner core of lower density amorphous carbon. The core is continuous throughout the carbon black aggregate, making the aggregate a stiff, integral unit. Contrast variation of swollen composite gels shows that there are two length scales in the gel structure. Above 10 Angstrom, scattering from carbon black predominates, and below 10 Angstrom the scattering is from both carbon black and the elastomer. The HSA in the composite is completely embedded in polyisoprene. An estimate of the carbon black structure factor shows strong exclusion of neighboring aggregates, probably from excluded volume effects. The surface structure of the carbon black is unaltered by the interactions with elastomer and appears smooth over length scales above about 10 Angstrom. These results show that contrast variation can provide information on composite structure that is not available by other means. This information relates to the reinforcement mechanism of elastomers by carbon blacks
Summary of neutron scattering lengths
International Nuclear Information System (INIS)
Koester, L.
1981-12-01
All available neutron-nuclei scattering lengths are collected together with their error bars in a uniform way. Bound scattering lengths are given for the elements, the isotopes, and the various spin-states. They are discussed in the sense of their use as basic parameters for many investigations in the field of nuclear and solid state physics. The data bank is available on magnetic tape, too. Recommended values and a map of these data serve for an uncomplicated use of these quantities. (orig.)
International Nuclear Information System (INIS)
Volkov, M.K.; Osipov, A.A.
1983-01-01
The msub(π)asub(0)sup(1/2)=0.1, msub(π)asub(0)sup(3/2)=-0.1, msub(π)asub(0)sup((-))=0.07, msub(π)sup(3)asub(1)sup(1/2)=0.018, msub(π)sup(3)asub(1)aup(3/2)=0.002, msub(π)sup(3)asub(1)sup((-))=0.0044, msub(π)sup(5)asub(2)sup(1/2)=2.4x10sup(-4) and msub(π)sup(5)asub(2)sup(3/2)=-1.2x10sup(-4) scattering lengths are calculated in the framework of the composite meson model which is based on four-quark interaction. The decay form factors of (rho, epsilon, S*) → 2π, (K tilde, K*) → Kπ are used. The q 2 -terms of the quark box diagrams are taken into account. It is shown that the q 2 -terms of the box diagrams give the main contribution to the s-wave scattering lengths. The diagrams with the intermediate vector mesons begin to play the essential role at calculation of the p- and d-wave scattering lengths
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
Small angle neutron scattering
International Nuclear Information System (INIS)
Bernardini, G.; Cherubini, G.; Fioravanti, A.; Olivi, A.
1976-09-01
A method for the analysis of the data derived from neutron small angle scattering measurements has been accomplished in the case of homogeneous particles, starting from the basic theory without making any assumption on the form of particle size distribution function. The experimental scattering curves are interpreted with the aid the computer by means of a proper routine. The parameters obtained are compared with the corresponding ones derived from observations at the transmission electron microscope
DEFF Research Database (Denmark)
Sivaramakrishnan, S.; Sung, J.; Ali, M.
2009-01-01
as a force transducer, rigid spacer, or flexible linker in proteins. In this study, we quantity this flexibility in terms of persistence length, namely the length scale over which it is rigid. We use single-molecule optical trapping and small-angle x-ray scattering, combined with Monte Carlo simulations...
Small angle neutron scattering
Directory of Open Access Journals (Sweden)
Cousin Fabrice
2015-01-01
Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of
Resonance effects in neutron scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Lynn, J.E.
1989-06-01
The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-/angstrom/ wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs.
Resonance effects in neutron scattering lengths
International Nuclear Information System (INIS)
Lynn, J.E.
1989-01-01
The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-angstrom wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs
Variational lower bound on the scattering length
International Nuclear Information System (INIS)
Rosenberg, L.; Spruch, L.
1975-01-01
The scattering length A characterizes the zero-energy scattering of one system by another. It was shown some time ago that a variational upper bound on A could be obtained using methods, of the Rayleigh-Ritz type, which are commonly employed to obtain upper bounds on energy eigenvalues. Here we formulate a method for obtaining a variational lower bound on A. Once again the essential idea is to express the scattering length as a variational estimate plus an error term and then to reduce the problem of bounding the error term to one involving bounds on energy eigenvalues. In particular, the variational lower bound on A is rigorously established provided a certin modified Hamiltonian can be shown to have no discrete states lying below the level of the continuum threshold. It is unfortunately true that necessary conditions for the existence of bound states are not available for multiparticle systems in general. However, in the case of positron-atom scattering the adiabatic approximation can be introduced as an (essentially) solvable comparison problem to rigorously establish the nonexistence of bound states of the modified Hamiltonian. It has recently been shown how the validity of the variational upper bound on A can be maintained when the target ground-state wave function is imprecisely known. Similar methods can be used to maintain the variational lower bound on A. Since the bound is variational, the error in the calculated scattering length will be of second order in the error in the wave function. The use of the adiabatic approximation in the present context places no limitation in principle on the accuracy achievable
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
Characterization of porous materials by small-angle scattering
Indian Academy of Sciences (India)
With the availability of ultra small-angle scattering instruments, one can investigate porous materials in the sub-micron length scale. Because of the increased accessible length scale vis-a-vis the multiple scattering effect, conventional data analysis procedures based on single scattering approximation quite often fail.
s -wave scattering length of a Gaussian potential
Jeszenszki, Peter; Cherny, Alexander Yu.; Brand, Joachim
2018-04-01
We provide accurate expressions for the s -wave scattering length for a Gaussian potential well in one, two, and three spatial dimensions. The Gaussian potential is widely used as a pseudopotential in the theoretical description of ultracold-atomic gases, where the s -wave scattering length is a physically relevant parameter. We first describe a numerical procedure to compute the value of the s -wave scattering length from the parameters of the Gaussian, but find that its accuracy is limited in the vicinity of singularities that result from the formation of new bound states. We then derive simple analytical expressions that capture the correct asymptotic behavior of the s -wave scattering length near the bound states. Expressions that are increasingly accurate in wide parameter regimes are found by a hierarchy of approximations that capture an increasing number of bound states. The small number of numerical coefficients that enter these expressions is determined from accurate numerical calculations. The approximate formulas combine the advantages of the numerical and approximate expressions, yielding an accurate and simple description from the weakly to the strongly interacting limit.
International Nuclear Information System (INIS)
Agamalian, M.M.; Alamo, R.G.; Londono, J.D.; Mandelkern, L.; Wignall, G.D.
1999-01-01
SANS experiments on blends of linear, high density (HD) and long chain branched, low density (LD) polyethylenes indicate that these systems form a one-phase mixture in the melt. However, the maximum spatial resolution of pinhole cameras is approximately equal to 10 3 and it has therefore been suggested that data might also be interpreted as arising from a bi-phasic melt with large a particle size ( 1 m), because most of the scattering from the different phases would not be resolved. We have addressed this hypothesis by means of USANS experiments, which confirm that HDPEILDPE blends are homogenous in the melt on length scales up to 20 m. We have also studied blends of HDPE and short-chain branched linear low density polyethylenes (LLDPEs), which phase separate when the branch content is sufficiently high. LLDPEs prepared with Ziegler-Natta catalysts exhibit a wide distribution of compositions, and may therefore be thought of as a blend of different species. When the composition distribution is broad enough, a fraction of highly branched chains may phase separate on m-length scales, and USANS has also been used to quantify this phenomenon
Taube, Michał; Pieńkowska, Joanna R.; Jarmołowski, Artur; Kozak, Maciej
2014-01-01
SGT1 is an evolutionarily conserved eukaryotic protein involved in many important cellular processes. In plants, SGT1 is involved in resistance to disease. In a low ionic strength environment, the SGT1 protein tends to form dimers. The protein consists of three structurally independent domains (the tetratricopeptide repeats domain (TPR), the CHORD- and SGT1-containing domain (CS), and the SGT1-specific domain (SGS)), and two less conserved variable regions (VR1 and VR2). In the present study, we provide the low-resolution structure of the barley (Hordeum vulgare) SGT1 protein in solution and its dimer/monomer equilibrium using small-angle scattering of synchrotron radiation, ab-initio modeling and circular dichroism spectroscopy. The multivariate curve resolution least-square method (MCR-ALS) was applied to separate the scattering data of the monomeric and dimeric species from a complex mixture. The models of the barley SGT1 dimer and monomer were formulated using rigid body modeling with ab-initio structure prediction. Both oligomeric forms of barley SGT1 have elongated shapes with unfolded inter-domain regions. Circular dichroism spectroscopy confirmed that the barley SGT1 protein had a modular architecture, with an α-helical TPR domain, a β-sheet sandwich CS domain, and a disordered SGS domain separated by VR1 and VR2 regions. Using molecular docking and ab-initio protein structure prediction, a model of dimerization of the TPR domains was proposed. PMID:24714665
Anomalous and resonance small-angle scattering
International Nuclear Information System (INIS)
Epperson, J.E.; Thiyagarajan, P.
1988-01-01
Significant changes in the small-angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous-dispersion terms for the scattering factor (X-rays) or scattering length (neutrons). The physics inherent in these anomalous-dispersion terms is first discussed before consideration of how they enter the relevant scattering theory. Two major areas of anomalous-scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with X-rays. However, it is pointed out that the formalism is the same for the analog experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small-angle neutron scattering are discussed. (orig.)
Exploiting Universality in Atoms with Large Scattering Lengths
International Nuclear Information System (INIS)
Braaten, Eric
2012-01-01
The focus of this research project was atoms with scattering lengths that are large compared to the range of their interactions and which therefore exhibit universal behavior at sufficiently low energies. Recent dramatic advances in cooling atoms and in manipulating their scattering lengths have made this phenomenon of practical importance for controlling ultracold atoms and molecules. This research project was aimed at developing a systematically improvable method for calculating few-body observables for atoms with large scattering lengths starting from the universal results as a first approximation. Significant progress towards this goal was made during the five years of the project.
Local-field refinement of neutron scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Sears, V F
1985-06-01
We examine the way in which local field effects in the neutron refractive index affect the values of coherent scattering lengths determined by various kinds of neutron optical measurements. We find that under typical experimental conditions these effects are negligible for interferometry measurements but that they are significant for gravity refractometry measurements, producing changes in the effective scattering length of as much as two or three standard deviations in some cases. Refined values of the scattering length are obtained for the thirteen elements for which data are presently available. The special role of local field effects in neutron transmission is also discussed.
Local-field refinement of neutron scattering lengths
International Nuclear Information System (INIS)
Sears, V.F.
1985-01-01
We examine the way in which local field effects in the neutron refractive index affect the values of coherent scattering lengths determined by various kinds of neutron optical measurements. We find that under typical experimental conditions these effects are negligible for interferometry measurements but that they are significant for gravity refractometry measurements, producing changes in the effective scattering length of as much as two or three standard deviations in some cases. Refined values of the scattering length are obtained for the thirteen elements for which data are presently available. The special role of local field effects in neutron transmission is also discussed. (orig.)
Small angle scattering and polymers
International Nuclear Information System (INIS)
Cotton, J.P.
1996-01-01
The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs
Isospin breaking in the pion-nucleon scattering lengths
International Nuclear Information System (INIS)
Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.
2009-01-01
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
Isospin breaking in the pion-nucleon scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Hoferichter, Martin [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany)], E-mail: kubis@itkp.uni-bonn.de; Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (Theorie), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2009-07-06
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
Synthesis of aerogel tiles with high light scattering length
Danilyuk, A F; Okunev, A G; Onuchin, A P; Shaurman, S A
1999-01-01
The possibility of aerogel tiles production for RICH detectors is described. Monolithic blocks of silica aerogel were synthesized by two-step sol-gel processing of tetraethoxysilane Si(OEt) sub 4 followed by high temperature supercritical drying with organic solvent. The important characteristic of aerogel is the light scattering length. In the wide range of refraction indexes the light scattering length exceeds 4 cm at 400 nm.
πd scattering lengths taking into account the pion and nucleon mass differences
International Nuclear Information System (INIS)
Pupyshev, V.V.; Rakityanskii, S.A.
1985-01-01
The scattering lengths and s-wave phase shifts for πd elastic scattering are calculated in the framework of an isotopically noninvariant approach that takes into account the mass splitting of the pionic and nucleonic isomultiplets. It is shown that the particle mass differences lead to appearance of the imaginary parts in the πd scattering lengths (approx.10 -4 fm) not associated with pion absorption. The sensitivity of the mass-difference effects to variation of the parameters of the πN potential is studied and turns out to be small
Light scattering by small particles
Hulst, H C van de
1981-01-01
""A must for researchers using the techniques of light scattering."" ? S. C. Snowdon, Journal of the Franklin InstituteThe measurement of light scattering of independent, homogeneous particles has many useful applications in physical chemistry, meteorology and astronomy. There is, however, a sizeable gap between the abstract formulae related to electromagnetic-wave-scattering phenomena, and the computation of reliable figures and curves. Dr. van de Hulst's book enables researchers to bridge that gap. The product of twelve years of work, it is an exhaustive study of light-scattering properties
A phenomenological π-p scattering length from pionic hydrogen
International Nuclear Information System (INIS)
Ericson, T.E.O.; Loiseau, B.; Wycech, S.
2004-01-01
We derive a closed, model independent, expression for the electromagnetic correction factor to a phenomenological hadronic scattering length a h extracted from a hydrogenic atom. It is obtained in a non-relativistic approach and in the limit of a short ranged hadronic interaction to terms of order α 2 logα using an extended charge distribution. A hadronic πN scattering length a h π - p =0.0870(5)m π -1 is deduced leading to a πNN coupling constant from the GMO relation g c 2 /(4π)=14.04(17)
A phenomenological $\\pi^{-}p$ scattering length from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2004-01-01
We derive a closed, model independent, expression for the electromagnetic correction factor to a phenomenological hadronic scattering length a/sup h/ extracted from a hydrogenic atom. It is obtained in a non-relativistic approach and in the limit of a short ranged hadronic interaction to terms of order alpha /sup 2/ log alpha using an extended charge distribution. A hadronic pi N scattering length a/sub pi -p//sup h/ = 0.0870(5)m/sub pi //sup -1/ is deduced leading to a pi NN coupling constant from the GMO relation g/sub c //sup 2//(4 pi ) = 14.04(17). (28 refs).
Scattering cross section of unequal length dipole arrays
Singh, Hema; Jha, Rakesh Mohan
2016-01-01
This book presents a detailed and systematic analytical treatment of scattering by an arbitrary dipole array configuration with unequal-length dipoles, different inter-element spacing and load impedance. It provides a physical interpretation of the scattering phenomena within the phased array system. The antenna radar cross section (RCS) depends on the field scattered by the antenna towards the receiver. It has two components, viz. structural RCS and antenna mode RCS. The latter component dominates the former, especially if the antenna is mounted on a low observable platform. The reduction in the scattering due to the presence of antennas on the surface is one of the concerns towards stealth technology. In order to achieve this objective, a detailed and accurate analysis of antenna mode scattering is required. In practical phased array, one cannot ignore the finite dimensions of antenna elements, coupling effect and the role of feed network while estimating the antenna RCS. This book presents the RCS estimati...
Neutron scattering lengths of molten metals determined by gravity refractometry
International Nuclear Information System (INIS)
Reiner, G.; Waschkowski, W.; Koester, L.
1990-01-01
Very accurate values of the coherent neutron scattering lengths of the heavy elements Bi and Pb are important quantities for the investigation of the electric interactions of neutrons with atoms. We performed, therefore, a series of experiments to determine accurate scattering lengths by means of neutron gravity refractometry on liquid mirrors of molten metals. The possible perturbations of the necessary reflection measurements have been discussed in details. After taking into account the uncertainties and corrections associated with observable perturbations we obtained the following values for bound atoms: b(Bi)=8.532±0.002 fm, b(Pb)=9.405±0.003 fm, b(Tl)=8.776±0.005 fm, b(Sn)=6.225±0.002 fm and b(Ga)=7.288±0.002 fm. These data are corrected for the local field effect occuring in the reflection on liquids. The recently reported results for the neutron's electric polarizability and the neutron-electron scattering length are supported by the Bi- and Pb-scattering length of this work. (orig.)
Neutron scattering lengths of molten metals determined by gravity refractometry
Energy Technology Data Exchange (ETDEWEB)
Reiner, G; Waschkowski, W; Koester, L [Technische Univ. Muenchen, Garching (Germany, F.R.). Fakultaet fuer Physik
1990-10-01
Very accurate values of the coherent neutron scattering lengths of the heavy elements Bi and Pb are important quantities for the investigation of the electric interactions of neutrons with atoms. We performed, therefore, a series of experiments to determine accurate scattering lengths by means of neutron gravity refractometry on liquid mirrors of molten metals. The possible perturbations of the necessary reflection measurements have been discussed in details. After taking into account the uncertainties and corrections associated with observable perturbations we obtained the following values for bound atoms: b(Bi)=8.532{plus minus}0.002 fm, b(Pb)=9.405{plus minus}0.003 fm, b(Tl)=8.776{plus minus}0.005 fm, b(Sn)=6.225{plus minus}0.002 fm and b(Ga)=7.288{plus minus}0.002 fm. These data are corrected for the local field effect occuring in the reflection on liquids. The recently reported results for the neutron's electric polarizability and the neutron-electron scattering length are supported by the Bi- and Pb-scattering length of this work. (orig.).
Neutron scattering lengths of molten metals determined by gravity refractometry
Energy Technology Data Exchange (ETDEWEB)
Reiner, G.; Waschkowski, W.; Koester, L. (Technische Univ. Muenchen, Garching (Germany, F.R.). Fakultaet fuer Physik)
1990-10-01
Very accurate values of the coherent neutron scattering lengths of the heavy elements Bi and Pb are important quantities for the investigation of the electric interactions of neutrons with atoms. We performed, therefore, a series of experiments to determine accurate scattering lengths by means of neutron gravity refractometry on liquid mirrors of molten metals. The possible perturbations of the necessary reflection measurements have been discussed in details. After taking into account the uncertainties and corrections associated with observable perturbations we obtained the following values for bound atoms: b(Bi)=8.532{plus minus}0.002 fm, b(Pb)=9.405{plus minus}0.003 fm, b(Tl)=8.776{plus minus}0.005 fm, b(Sn)=6.225{plus minus}0.002 fm and b(Ga)=7.288{plus minus}0.002 fm. These data are corrected for the local field effect occuring in the reflection on liquids. The recently reported results for the neutron's electric polarizability and the neutron-electron scattering length are supported by the Bi- and Pb-scattering length of this work. (orig.).
Scattering of acoustic waves by small crustaceans
Andreeva, I. B.; Tarasov, L. L.
2003-03-01
Features of underwater sound scattering by small crustaceans are considered. The scattering data are obtained with the use of unique instrumentation that allows one to measure quantitative scattering characteristics (backscattering cross sections and angular scattering patterns) for crustaceans of different sizes, at different frequencies (20 200 kHz) and different insonification aspects. A computational model of crustaceans is considered with allowance for both the soft tissues of the main massive part of the animal's body and the stiff armour. The model proves to be advantageous for explaining some scattering features observed in the experiments. The scattering cross sections of crustaceans measured by other researchers are presented in a unified form appropriate for comparison. Based on such a quantitative comparison, relatively simple approximate empirical formulas are proposed for estimating the backscattering cross sections of small (within several centimeters) marine crustaceans in a broad frequency range.
A national facility for small angle neutron scattering
International Nuclear Information System (INIS)
Buyers, W.J.L.; Katsaras, J.; Mellors, W.; Potter, M.M.; Powell, B.M.; Rogge, R.B.; Root, J.H.; Tennant, D.C.; Tun, Z.
1995-01-01
A world-class small angle neutron scattering (SANS) facility is proposed for Canada. It will provide users from the fields of biology, chemistry, physics, materials science and engineering with a uniquely powerful tool for investigating microstructural properties whose length scales lie in the optical to atomic range. (author). 7 refs
A national facility for small angle neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Buyers, W J.L.; Katsaras, J; Mellors, W; Potter, M M; Powell, B M; Rogge, R B; Root, J H; Tennant, D C; Tun, Z [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Epand, R; Gaulin, B D [McMaster Univ., Hamilton, ON (Canada)
1995-09-15
A world-class small angle neutron scattering (SANS) facility is proposed for Canada. It will provide users from the fields of biology, chemistry, physics, materials science and engineering with a uniquely powerful tool for investigating microstructural properties whose length scales lie in the optical to atomic range. (author). 7 refs.
Small angle neutron scattering by polymer solutions
International Nuclear Information System (INIS)
Farnoux, B.; Jannink, G.
1980-08-01
Small angle neutron scattering is an experimental technique introduced since about 10 years for the observation of the polymer conformation in all the concentration range from dilute solution to the melt. After a brief recall of the elementary relations between scattering amplitude, index of refraction and scattered intensity, two concepts related to this last quantity (the contrast and the pair correlation function) are discussed in details
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.
Small-angle neutron-scattering experiments
International Nuclear Information System (INIS)
Hardy, A.D.; Thomas, M.W.; Rouse, K.D.
1981-04-01
A brief introduction to the technique of small-angle neutron scattering is given. The layout and operation of the small-angle scattering spectrometer, mounted on the AERE PLUTO reactor, is also described. Results obtained using the spectrometer are presented for three materials (doped uranium dioxide, Magnox cladding and nitrided steel) of interest to Springfields Nuclear Power Development Laboratories. The results obtained are discussed in relation to other known data for these materials. (author)
Coulomb corrections to scattering length and effective radius
International Nuclear Information System (INIS)
Mur, V.D.; Kudryavtsev, A.E.; Popov, V.S.
1983-01-01
The problem considered is extraction of the ''purely nuclear'' scattering length asub(s) (corresponding to the strong potential Vsub(s) at the Coulomb interaction switched off) from the Coulomb-nuclear scattering length asub(cs), which is an object of experimental measurement. The difference between asub(s) and asub(cs) is especially large if the potential Vsub(s) has a level (real or virtual) with an energy close to zero. For this case formulae are obtained relating the scattering lengths asub(s) and asub(cs), as well as the effective radii rsub(s) and rsub(cs). The results are extended to states with arbitrary angular momenta l. It is shown that the Coulomb correction is especially large for the coefficient with ksup(2l) in the expansion of the effective radius; in this case the correction contains a large logarithm ln(asub(B)/rsub(0)). The Coulomb renormalization of other terms in the effective radius espansion is of order (rsub(0)/asub(B)), where r 0 is the nuclear force radius, asub(B) is the Bohr radius. The obtained formulae are tried on a number of model potentials Vsub(s), used in nuclear physics
Atom-dimer scattering in a heteronuclear mixture with a finite intraspecies scattering length
Gao, Chao; Zhang, Peng
2018-04-01
We study the three-body problem of two ultracold identical bosonic atoms (denoted by B ) and one extra atom (denoted by X ), where the scattering length aB X between each bosonic atom and atom X is resonantly large and positive. We calculate the scattering length aad between one bosonic atom and the shallow dimer formed by the other bosonic atom and atom X , and investigate the effect induced by the interaction between the two bosonic atoms. We find that even if this interaction is weak (i.e., the corresponding scattering length aB B is of the same order of the van der Waals length rvdW or even smaller), it can still induce a significant effect for the atom-dimer scattering length aad. Explicitly, an atom-dimer scattering resonance can always occur when the value of aB B varies in the region with | aB B|≲ rvdW . As a result, both the sign and the absolute value of aad, as well as the behavior of the aad-aB X function, depends sensitively on the exact value of aB B. Our results show that, for a good quantitative theory, the intraspecies interaction is required to be taken into account for this heteronuclear system, even if this interaction is weak.
Modeling small angle scattering data using FISH
International Nuclear Information System (INIS)
Elliott, T.; Buckely, C.E.
2002-01-01
Full text: Small angle neutron scattering (SANS) and small angle x-ray scattering (SAXS) are important techniques for the characterisation of samples on the nanometer scale. From the scattered intensity pattern information about the sample such as particle size distribution, concentration and particle interaction can be determined. Since the experimental data is in reciprocal space and information is needed about real space, modeling of the scattering data to obtain parameters is extremely important and several paradigms are available. The use of computer programs to analyze the data is imperative for a robust description of the sample to be obtained. This presentation gives an overview of the SAS process and describes the data-modeling program FISH, written by R. Heenan 1983-2000. The results of using FISH to obtain the particle size distribution of bubbles in the aluminum hydrogen system and other systems of interest are described. Copyright (2002) Australian X-ray Analytical Association Inc
Nucleon-nucleon scattering length from three-body reactions
International Nuclear Information System (INIS)
Bodek, K.
1989-01-01
Experiments aimed at the measurement of the singlet scattering lengths 1 a np and 1 a nn of the NN-interaction in the presence of a heavy spectator are described. The values obtained are compared with the results of measurements of other reactions. The very good agreement of the experimental values of 1 a np from all breakup reactions and elastic scattering as well as agreement of the values of 1 a nn from breakup reactions and disagreement with the value from the π - d → nnγ reaction cast doubts on the hypothesis ascribing this discrepancy to a 3N-force. This result also suggests a stronger effect of a violation of the charge independence principle than previously accepted. 101 refs., 18 figs., 3 tabs. (author)
Small-angle neutron scattering instrument at MINT
International Nuclear Information System (INIS)
Mohd Ali Sufi; Yusof Abdullah; Razali Kassim; Hamid; Shahidan Radiman; Mohammad Deraman; Abdul Ghaffar Ramli
1996-01-01
The Small Angle Neutron Scattering (SANS) Instrument has been developed at Malaysian Institute for Nuclear Technology Research (MINT) for studying structural properties of materials on the length scale 1 nm to 100 nm. This is the length scale which is relevant for many topics within soft condensed matter, like polymers, colloids, biological macromolecules, etc. The SANS is a complementary technique to X-ray and electron scattering. However, while these later techniques give information on structures near surface, SANS concerns the structure of the bulk. Samples studied by SANS technique are typically bulk materials of the sizes mm's to cm's, or materials dissolved in a liquid. This paper described the general characteristics of SANS instrument as well as the experimental formulation in neutron scattering. The preliminary results obtained by this instrument are shown
Small angle neutron scattering and small angle X-ray scattering ...
Indian Academy of Sciences (India)
Abstract. The morphology of carbon nanofoam samples comprising platinum nanopar- ticles dispersed in the matrix was characterized by small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) techniques. Results show that the structure of pores of carbon matrix exhibits a mass (pore) fractal nature ...
Scattering Length Scaling Laws for Ultracold Three-Body Collisions
International Nuclear Information System (INIS)
D'Incao, J.P.; Esry, B.D.
2005-01-01
We present a simple and unifying picture that provides the energy and scattering length dependence for all inelastic three-body collision rates in the ultracold regime for three-body systems with short-range two-body interactions. Here, we present the scaling laws for vibrational relaxation, three-body recombination, and collision-induced dissociation for systems that support s-wave two-body collisions. These systems include three identical bosons, two identical bosons, and two identical fermions. Our approach reproduces all previous results, predicts several others, and gives the general form of the scaling laws in all cases
Assessing Telomere Length Using Surface Enhanced Raman Scattering
Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Cui, Yiping
2014-11-01
Telomere length can provide valuable insight into telomeres and telomerase related diseases, including cancer. Here, we present a brand-new optical telomere length measurement protocol using surface enhanced Raman scattering (SERS). In this protocol, two single strand DNA are used as SERS probes. They are labeled with two different Raman molecules and can specifically hybridize with telomeres and centromere, respectively. First, genome DNA is extracted from cells. Then the telomere and centromere SERS probes are added into the genome DNA. After hybridization with genome DNA, excess SERS probes are removed by magnetic capturing nanoparticles. Finally, the genome DNA with SERS probes attached is dropped onto a SERS substrate and subjected to SERS measurement. Longer telomeres result in more attached telomere probes, thus a stronger SERS signal. Consequently, SERS signal can be used as an indicator of telomere length. Centromere is used as the inner control. By calibrating the SERS intensity of telomere probe with that of the centromere probe, SERS based telomere measurement is realized. This protocol does not require polymerase chain reaction (PCR) or electrophoresis procedures, which greatly simplifies the detection process. We anticipate that this easy-operation and cost-effective protocol is a fine alternative for the assessment of telomere length.
Studies in small angle scattering techniques
International Nuclear Information System (INIS)
Moellenbach, K.
1980-03-01
Small angle scattering of neutrons, X-rays and γ-rays are found among the spectroscopic methods developed in the recent years. Although these techniques differ from each other in many respects, e.g. radiation sources and technical equipment needed, their power to resolve physical phenomena and areas of application can be discussed in a general scheme. Selected examples are given illustrating the use of specific technical methods. Jahn-Teller driven structural phase transitions in Rare Earth zircons were studied with neutron scattering as well as small angle γ-ray diffraction. The study of neutron scattering from formations of magnetic domains in the Ising ferromagnet LiTbF 4 is a second example. Both these examples represent more than experimental test cases since the theoretical interpretations of the data obtained are discussed as well. As a last example the use of small angle scattering methods for the study of molecular biological samples is discussed. In particular the experimental procedures used in connection with scattering from aqueous solutions of proteins and protein complexes are given. (Auth.)
Experimental technique of small angle neutron scattering
International Nuclear Information System (INIS)
Xia Qingzhong; Chen Bo
2006-03-01
The main parts of Small Angle Neutron Scattering (SANS) spectrometer, and their function and different parameters are introduced from experimental aspect. Detailed information is also introduced for SANS spectrometer 'Membrana-2'. Based on practical experiments, the fundamental requirements and working condition for SANS experiments, including sample preparation, detector calibration, standard sample selection and data preliminary process are described. (authors)
Small Angle X-Ray Scattering Detector
Energy Technology Data Exchange (ETDEWEB)
Hessler, Jan P.
2004-06-15
A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.
Energy Technology Data Exchange (ETDEWEB)
Baru, V. [Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44870 Bochum (Germany); Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Theoretical and Experimental Physics, B. Cheremushinskaya 25, 117218 Moscow (Russian Federation); Hanhart, C. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany); Hoferichter, M., E-mail: hoferichter@hiskp.uni-bonn.de [Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institute of Nuclear and Particle Physics and Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States); Kubis, B. [Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Nogga, A. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2011-12-15
We use chiral perturbation theory (ChPT) to calculate the {pi}{sup -}d scattering length with an accuracy of a few percent, including isospin-violating corrections in both the two- and three-body sectors. In particular, we provide the technical details of a recent letter (Baru et al., 2011) , where we used data on pionic deuterium and pionic hydrogen atoms to extract the isoscalar and isovector pion-nucleon scattering lengths a{sup +} and a{sup -}. We study isospin-breaking contributions to the three-body part of a{sub {pi}}{sup -}{sub d} due to mass differences, isospin violation in the {pi}N scattering lengths, and virtual photons. This last class of effects is ostensibly infrared enhanced due to the smallness of the deuteron binding energy. However, we show that the leading virtual-photon effects that might undergo such enhancement cancel, and hence the standard ChPT counting provides a reliable estimate of isospin violation in a{sub {pi}}{sup -}{sub d} due to virtual photons. Finally, we discuss the validity of the Goldberger-Miyazawa-Oehme sum rule in the presence of isospin violation, and use it to determine the charged-pion-nucleon coupling constant.
Precision calculation of threshold πd scattering, πN scattering lengths, and the GMO sum rule
Baru, V.; Hanhart, C.; Hoferichter, M.; Kubis, B.; Nogga, A.; Phillips, D. R.
2011-12-01
We use chiral perturbation theory (ChPT) to calculate the πd scattering length with an accuracy of a few percent, including isospin-violating corrections in both the two- and three-body sectors. In particular, we provide the technical details of a recent letter (Baru et al., 2011) [1], where we used data on pionic deuterium and pionic hydrogen atoms to extract the isoscalar and isovector pion-nucleon scattering lengths a and a. We study isospin-breaking contributions to the three-body part of a due to mass differences, isospin violation in the πN scattering lengths, and virtual photons. This last class of effects is ostensibly infrared enhanced due to the smallness of the deuteron binding energy. However, we show that the leading virtual-photon effects that might undergo such enhancement cancel, and hence the standard ChPT counting provides a reliable estimate of isospin violation in a due to virtual photons. Finally, we discuss the validity of the Goldberger-Miyazawa-Oehme sum rule in the presence of isospin violation, and use it to determine the charged-pion-nucleon coupling constant.
Universality in few-body systems with large scattering length
International Nuclear Information System (INIS)
Hammer, H.-W.
2005-01-01
Effective Field Theory (EFT) provides a powerful framework that exploits a separation of scales in physical systems to perform systematically improvable, model-independent calculations. Particularly interesting are few-body systems with short-range interactions and large two-body scattering length. Such systems display remarkable universal features. In systems with more than two particles, a three-body force with limit cycle behavior is required for consistent renormalization already at leading order. We will review this EFT and some of its applications in the physics of cold atoms and nuclear physics. In particular, we will discuss the possibility of an infrared limit cycle in QCD. Recent extensions of the EFT approach to the four-body system and N-boson droplets in two spatial dimensions will also be addressed
Small-angle scattering study of Aspergillus awamori glycoprotein glucoamylase
International Nuclear Information System (INIS)
Schmidt, A. E.; Shvetsov, A. V.; Kuklin, A. I.; Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V.
2016-01-01
Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å
Small-angle scattering study of Aspergillus awamori glycoprotein glucoamylase
Schmidt, A. E.; Shvetsov, A. V.; Kuklin, A. I.; Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V.
2016-01-01
Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å.
Small-angle scattering study of Aspergillus awamori glycoprotein glucoamylase
Energy Technology Data Exchange (ETDEWEB)
Schmidt, A. E., E-mail: schmidt@omrb.pnpi.spb.ru; Shvetsov, A. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation); Kuklin, A. I. [Joint Institute for Nuclear Research (Russian Federation); Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)
2016-01-15
Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å.
Small angle neutron scattering (SANS) under non-equilibrium conditions
International Nuclear Information System (INIS)
Oberthur, R.C.
1984-01-01
The use of small angle neutron scattering (SANS) for the study of systems under non-equilibrium conditions is illustrated by three types of experiments in the field of polymer research: - the relaxation of a system from an initial non-equilibrium state towards equilibrium, - the cyclic or repetitive installation of a series of non-equilibrium states in a system, - the steady non-equilibrium state maintained by a constant dissipation of energy within the system. Characteristic times obtained in these experiments with SANS are compared with the times obtained from quasi-elastic neutron and light scattering, which yield information about the equilibrium dynamics of the system. The limits of SANS applied to non-equilibrium systems for the measurement of relaxation times at different length scales are shown and compared to the limits of quasielastic neutron and light scattering
Lateral displacement in small angle multiple scattering
Energy Technology Data Exchange (ETDEWEB)
Bichsel, H.; Hanson, K.M.; Schillaci, K.M. (Los Alamos National Lab., NM (USA))
1982-07-01
Values have been calculated for the average lateral displacement in small angle multiple scattering of protons with energies of several hundred MeV. The calculations incorporate the Moliere distribution which does not make the gaussian approximations of the distribution in projected angle and lateral deflections. Compared to other published data, such approximations can lead to errors in the lateral displacement of up to 10% in water.
Magnetic corrections to π -π scattering lengths in the linear sigma model
Loewe, M.; Monje, L.; Zamora, R.
2018-03-01
In this article, we consider the magnetic corrections to π -π scattering lengths in the frame of the linear sigma model. For this, we consider all the one-loop corrections in the s , t , and u channels, associated to the insertion of a Schwinger propagator for charged pions, working in the region of small values of the magnetic field. Our calculation relies on an appropriate expansion for the propagator. It turns out that the leading scattering length, l =0 in the S channel, increases for an increasing value of the magnetic field, in the isospin I =2 case, whereas the opposite effect is found for the I =0 case. The isospin symmetry is valid because the insertion of the magnetic field occurs through the absolute value of the electric charges. The channel I =1 does not receive any corrections. These results, for the channels I =0 and I =2 , are opposite with respect to the thermal corrections found previously in the literature.
Electromagnetic wave scattering by many small particles
International Nuclear Information System (INIS)
Ramm, A.G.
2007-01-01
Scattering of electromagnetic waves by many small particles of arbitrary shapes is reduced rigorously to solving linear algebraic system of equations bypassing the usual usage of integral equations. The matrix elements of this linear algebraic system have physical meaning. They are expressed in terms of the electric and magnetic polarizability tensors. Analytical formulas are given for calculation of these tensors with any desired accuracy for homogeneous bodies of arbitrary shapes. An idea to create a 'smart' material by embedding many small particles in a given region is formulated
International Nuclear Information System (INIS)
Rupnik, K.; Asaf, U.; McGlynn, S.P.
1990-01-01
A linear correlation exists between the electron scattering length, as measured by a pressure shift method, and the polarizabilities for He, Ne, Ar, Kr, and Xe gases. The correlative algorithm has excellent predictive capability for the electron scattering lengths of mixtures of rare gases, simple molecular gases such as H 2 and N 2 and even complex molecular entities such as methane, CH 4
Scattering by ensembles of small particles
International Nuclear Information System (INIS)
Gustafson, B. Aa. S.
1980-11-01
With the advent of high altitude rockets and of space probes, evidence has accumulated that several particle types coexiste in the interplanetary medium. It also became apparent that the zodiacal light is not produced by particles with previously known scattering characteristics. However, the scattering is here shown to be consistent with the hypothesis that presolar interstellar grains accumulate into comets which through fragmentation provide a major component of the interplanetary dust complex. Cometary debris - zodiscal light particles - are therefore modeled as conglomerates of elongated core-mantle particles. Light scattering characteristics of the conglomerates are investigated using a micro-wave analogue method. Approximate theoretical methods for prediction and interpretation of the electro-magnetic scattering patterns are developed and are found to compare favorably with the experimental results and with observations of the zodiacal light. The model is also found to be consistent with comet- and impactdata. Dynamical considerations predicts a small particle component rapidly receding from the Sun, an identification with the B-meteoroids is tentatively suggested. (author)
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
Neutron elastic scattering at very small angles
2002-01-01
This experiment will measure neutron-proton elastic scattering at very small angles and hence very small four-momentum transfer, |t|. The range of |t| depends on the incident neutron momentum of the events but the geometrical acceptance will cover the angular range 0.025 < $\\Theta_{lab}$ < 1.9 mrad. The higher figure could be extended to 8.4 mrad by changing the geometry of the experiment in a later phase. \\\\ \\\\ The neutron beam will be highly collimated and will be derived from a 400 GeV external proton beam of up to $4 \\times 10^{10}$ protons per pulse in the SPS North Area Hall 1. The hydrogen target will be gaseous, operating at 40 atm. pressure and acts as a multiwire proportional chamber to detect the recoil protons. The forward neutron will be detected and located by interaction in a neutron vertex detector and its energy measured by a conventional steel plate calorimeter. \\\\ \\\\ The experiment will cover the angular region of nucleon-nucleon scattering which is dominated by Coulomb scattering ...
Extracting $p\\Lambda$ scattering lengths from heavy ion collisions
Shapoval, V M; Lednicky, R; Sinyukov, Yu M
2015-01-01
The $p-\\Lambda \\oplus \\bar{p}-\\bar{\\Lambda}$ and $\\bar{p}-\\Lambda \\oplus p-\\bar{\\Lambda}$ correlation functions for 10% most central Au+Au collisions at top RHIC energy $\\sqrt{s_{NN}}=200$ GeV are modeled with Lednicky and Lyuboshitz analytical formula using the source radii extracted from the hydrokinetic model (HKM) simulations. For the baryon-antibaryon case the corresponding spin-averaged strong interaction scattering length is obtained by fitting the STAR correlation function. In contrast to the experimental results, where extracted $p\\bar{\\Lambda}$ source radius value was found $\\sim 2$ times smaller than the corresponding $p\\Lambda$ one, the calculations in HKM show both $p\\Lambda$ and $p\\bar{\\Lambda}$ effective source radii to be quite close, as expected from theoretical considerations. To obtain the satisfactory fit to the measured baryon-antibaryon correlation function at this large source radius value, the modified analytical approximation to the correlation function, effectively accounting for the...
The TUNL neutron-neutron scattering length experiment
International Nuclear Information System (INIS)
Trotter, D.E.G.; Tornow, W.; Howell, C.R.
1995-01-01
Since an accurate value for the neutron-neutron (nn) scattering length a nn is of fundamental interest, its determination should not rely on one source of experimental information only. Besides the π d capture reaction, the nd breakup reaction has been the classical reaction used for determining a nn . However, none of the published values for a nn obtained from kinematically complete nd → n+n+p breakup data are based on a rigorous treatment of the three-nucleon continuum. In addition, the scale uncertainty associated with the existing nd breakup cross-section data in the region of the nn final-state interaction peak is too large to allow for a meaningful reanalysis. Therefore, a new kinematically complete nd breakup experiment is underway at TUNL at an incident neutron energy of 13 MeV. State-of-the-art three-nucleon continuum calculations will be used to analyze the data. In order to investigate the possible influence of three-nucleon force effects, a nn will be determined from data taken at four production angles of the nn pair between 20.5 degrees and 43 degrees (lab)
Neutron-triton scattering lengths for interactions reproducing low-energy trinucleon data
International Nuclear Information System (INIS)
Levashev, V.P.
1981-01-01
By solving the integral equations for four nucleons the neutron-triton scattering lengths and total cross section are calculated using different S-wave rank-one separable potentials. A number of linear correlations between the neutron-triton scattering lengths and triton binding energy are found. The scattering lengths consistent with low-energy trinucleon data. The results obtained are compared with available experimental data [ru
Analysis of an atom laser based on the spatial control of the scattering length
International Nuclear Information System (INIS)
Carpentier, Alicia V.; Michinel, Humberto; Rodas-Verde, Maria I.; Perez-Garcia, Victor M.
2006-01-01
In this paper we analyze atom lasers based on the spatial modulation of the scattering length of a Bose-Einstein condensate. We demonstrate, through numerical simulations and approximate analytical methods, the controllable emission of matter-wave bursts and study the dependence of the process on the spatial shape of the scattering length along the axis of emission. We also study the role of an additional modulation of the scattering length in time
Pair production in small angle Bhabha scattering
International Nuclear Information System (INIS)
Arbuzov, A.B.; Kuraev, Eh.A.; Merenkov, N.P.; Trentadue, L.
1995-01-01
The radiative corrections due to a pair production in the small angle high energy e + e - Bhabha scattering are considered. The corrections due to the production of virtual pairs as well as real soft and hard ones are calculated analytically. The collinear and semi-collinear kinematical regions of the hard pair production are taken into account. The results in the leading and next-to-leading logarithmic approximations provide the accuracy of Ο (0.1%). The results of numerical calculations show that the effects of pairs production are to be taken into account in the precise luminosity determination at LEP. 9 refs., 3 figs., 2 tabs
International Nuclear Information System (INIS)
Jayaswal, B.; Mazumder, S.
1998-09-01
Small-angle scattering data from strong scattering systems, e.g. porous materials, cannot be analysed invoking single scattering approximation as specimen needed to replicate the bulk matrix in essential properties are too thick to validate the approximation. The presence of multiple scattering is indicated by invalidity of the functional invariance property of the observed scattering profile with variation of sample thickness and/or wave length of the probing radiation. This article delineates how non accounting of multiple scattering affects the results of analysis and then how to correct the data for its effect. It deals with an algorithm to extract single scattering profile from small-angle scattering data affected by multiple scattering. The algorithm can process the scattering data and deduce single scattering profile in absolute scale. A software package, SIMSAS, is introduced for executing this inversion step. This package is useful both to simulate and to analyse multiple small-angle scattering data. (author)
Hadron elastic scattering at small angles
2002-01-01
This experiment is an extension of the measurements of the WA9 experiment up to the highest energies available in the North Area. It will measure the differential cross-section for hadron elastic scattering in the t-range 0.002-0.05 (GeV/c)$^{2}$ using an ionization chamber for the measurement of the energy and the angle of the recoil and a magnet-WC spectrometer to measure the momentum and direction of the forward particle. From these measurements will be obtained the ratio $\\rho$ of the real to imaginary parts of the forward elastic amplitude and the exponential slope parameter b of the hadronic amplitude at small t. The precision expected in these measurements is $\\Delta \\rho \\approx \\pm 0.01$ and $\\Delta$b $\\approx \\pm 0.2$ (GeV/c)$^{-2}$. \\\\ \\\\ The experimental programme includes: \\\\\\\\ i) measurements of $\\rho$ and b for $\\pi$p elastic scattering at incident momenta between 150 GeV/c and 300 GeV/c; \\\\ ii) measurements of $\\rho$ and b for $\\pi^{+}$p and pp elastic scattering at incident momenta between 5...
X-ray small angle scattering of polymer solutions
International Nuclear Information System (INIS)
Koyama, Ryuzo
1975-01-01
In recent papers, the calculated results were reported on the angular dependence of the intensity of scattered light or X-ray by chain polymers, on the basis of a stiff chain model. As the results, the curves of S 2 P (theta) corresponding to Kratky plot, for different molecular expansion, showed a plateau, and the height of the plateau was proportional to the inverse of molecular expansion coefficient α 2 . But as seen later, there is some possibility that the assumption made in the calculation overestimated the expansion of small segments which theoretically determines scattering curves at large scattering angles, such as the plateau. Accordingly, modified calculation was carried out by adopting the stiff chain polymer model as the previous case. When the contour length of a chain segment is very long, it can be treated approximately as a Gaussian coil, thus the equation for a chain segment expansion coefficient α (t) was obtained. Then the mean square distance of chain segments of polymer molecules was able to be determined, and the equation for a particle scattering factor P(theta) was obtained. The numerical calculation of P(theta) showed that this modified assumption considerably decreased the effect of molecular expansion on P(theta), and the curves of S 2 P(theta) increased monotonously without showing the plateau. The result of this calculation was compared with the experimental curves of polystyrene-toluene solution, and the agreement better than before was obtained. (Kako, I.)
A method to measure the antikaon-nucleon scattering length in lattice QCD
International Nuclear Information System (INIS)
Lage, Michael; Meissner, Ulf-G.; Rusetsky, Akaki
2009-01-01
We propose a method to determine the isoscalar K-bar N scattering length on the lattice. Our method represents the generalization of Luescher's approach in the presence of inelastic channels (complex scattering length). In addition, the proposed approach allows one to find the position of the S-matrix pole corresponding the Λ(1405) resonance.
Langmack, Christian; Schmidt, Richard; Zwerger, Wilhelm
2018-03-01
We calculate the spectrum of three-body Efimov bound states near a Feshbach resonance within a model which accounts both for the finite range of interactions and the presence of background scattering. The latter may be due to direct interactions in an open channel or a second overlapping Feshbach resonance. It is found that background scattering gives rise to substantial changes in the trimer spectrum as a function of the detuning away from a Feshbach resonance, in particular in the regime where the background channel supports Efimov states on its own. Compared to the situation with negligible background scattering, the regime where van der Waals universality applies is shifted to larger values of the resonance strength if the background scattering length is positive. For negative background scattering lengths, in turn, van der Waals universality extends to even small values of the resonance strength parameter, consistent with experimental results on Efimov states in 39K. Within a simple model, we show that short-range three-body forces do not affect van der Waals universality significantly. Repulsive three-body forces may, however, explain the observed variation between around -8 and -10 of the ratio between the scattering length where the first Efimov trimer appears and the van der Waals length.
Small-angle scattering in materials science
International Nuclear Information System (INIS)
Paris, O.; Fratzl, P.
1999-01-01
Small-angle scattering (SAS) of X-rays (SAXS) or neutrons (SANS) are a powerful tools to investigate inhomogeneities in the size range from ∼ 1 nm to ∼ 100 nm. Typical examples in materials science are pores, precipitates in metal alloys or nano-particles in composites. Frequently, these inhomogeneities are not spherical and their alignment is not random, quite in contrast to many other applications of SAS. This requires the use of pinhole geometry and area detectors for the experimental set-up. The present paper focuses on evaluation techniques of two-dimensional (2D) SAS-patterns from some materials investigated by the authors, i.e. metal alloys, carbon composites, wood and bone. Although the examples shown are derived exclusively from SAXS measurements, most of them could stem from SANS measurements as well. (author)
Fluorescent scattering by molecules embedded in small particles
International Nuclear Information System (INIS)
1982-01-01
Studies are reported in these areas: double resonance in fluorescent and Raman scattering; surface enhanced Raman scattering; fluorescence by molecules embedded in small particles; fluorescence by a liquid droplet; and fluorescence by conical pits in surfaces
International Nuclear Information System (INIS)
Saha, H.P.
1993-01-01
The multiconfiguration Hartree-Fock method for continuum wave functions has been used to calculate the scattering length and phase shifts over extremely low energies ranging from 0 to 1 eV very accurately for electron-helium scattering. The scattering length is calculated very accurately with wave functions computed exactly at zero energy, resulting in an upper bound of 1.1784. The electron correlation and polarization of the target by the scattering electron, which are very important in these calculations, have been taken into account in an accurate ab initio manner through the configuration-interaction procedure by optimizing both bound and continuum orbitals simultaneously at each kinetic energy of the scattered electron. Detailed results for scattering length, differential, total, and momentum-transfer cross sections obtained from the phase shifts are presented. The present scattering length is found to be in excellent agreement with the experimental result of Andrick and Bitsch [J. Phys. B 8, 402 (1975)] and the theoretical result of O'Malley, Burke, and Berrington [J. Phys. B 12, 953 (1979)]. There is excellent agreement between the present total cross sections and the corresponding experimental measurements of Buckman and Lohmann [J. Phys. B 19, 2547 (1986)]. The present momentum-transfer cross sections also show remarkable agreement with the experimental results of Crompton, Elford, and Robertson [Aust. J. Phys. 23, 667 (1970)
Scattering-matrix elements of coated infinite-length cylinders
International Nuclear Information System (INIS)
Manickavasagam, S.; Menguec, M.P.
1998-01-01
The angular variations of scattering-matrix elements of coated cylindrical particles are presented. The sensitivity of different elements for a number of physical parameters are discussed, including size parameter, real and imaginary parts of the refractive index of the outer coat, and the inner core. The numerical predictions are presented for typical index-of-refraction values of cotton fibers. These results show that the physical structure of coated cylinders can be determined from carefully conducted light-scattering experiments. copyright 1998 Optical Society of America
A Small Crack Length Evaluation Technique by Electronic Scanning
International Nuclear Information System (INIS)
Cho, Yong Sang; Kim, Jae Hoon
2009-01-01
The results of crack evaluation by conventional UT(Ultrasonic Test)is highly depend on the inspector's experience or knowledge of ultrasound. Phased array UT system and its application methods for small crack length evaluation will be a good alternative method which overcome present UT weakness. This study was aimed at checking the accuracy of crack length evaluation method by electronic scanning and discuss about characteristics of electronic scanning for crack length evaluation. Especially ultrasonic phased array with electronic scan technique was used in carrying out both sizing and detect ability of crack as its length changes. The response of ultrasonic phased array was analyzed to obtain the special method of determining crack length without moving the transducer and detectability of crack minimal length and depth from the material. A method of crack length determining by electronic scanning for the small crack is very real method which has it's accuracy and verify the effectiveness of method compared to a conventional crack length determination
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
Small-angle neutron scattering technique in liquid crystal studies
International Nuclear Information System (INIS)
Shahidan Radiman
2005-01-01
The following topics discussed: general principles of SAS (Small-angle Neutron Scattering), liquid crystals, nanoparticle templating on liquid crystals, examples of SAS results, prospects of this studies
Multiple small-angle neutron scattering studies of anisotropic materials
Allen, A J; Long, G G; Ilavsky, J
2002-01-01
Building on previous work that considered spherical scatterers and randomly oriented spheroidal scatterers, we describe a multiple small-angle neutron scattering (MSANS) analysis for nonrandomly oriented spheroids. We illustrate this with studies of the multi-component void morphologies found in plasma-spray thermal barrier coatings. (orig.)
Soller collimators for small angle neutron scattering
International Nuclear Information System (INIS)
Crawford, R.K.; Epperson, J.E.; Thiyagarajan, P.
1989-01-01
The neutron beam transmitted through the soller collimators on the SAD (Small Angle Diffractometer) instrument at IPNS (Intense Pulsed Neutron Source) showed wings about the main beam. These wings were quite weak, but were sufficient to interfere with the low-Q scattering data. General considerations of the theory of reflection from homogeneous absorbing media, combined with the results from a Monte Carlo simulation, suggested that these wings were due to specular reflection of neutrons from the absorbing material on the surfaces of the collimator blades. The simulations showed that roughness of the surface was extremely important, with wing background variations of three orders of magnitude being observed with the range of roughness values used in the simulations. Based on the results of these simulations, new collimators for SAD were produced with a much rougher 10 B-binder surface coating on the blades. These new collimators were determined to be significantly better than the original SAD collimators. This work suggests that any soller collimators designed for use with long wavelengths should be fabricated with such a rough surface coating, in order to eliminate (or at least minimize) the undesirable reflection effects which otherwise seem certain to occur. 4 refs., 6 figs
Absorption and scattering of light by small particles
Bohren, Craig F
1983-01-01
Absorption and Scattering of Light by Small Particles. Treating absorption and scattering in equal measure, this self-contained, interdisciplinary study examines and illustrates how small particles absorb and scatter light. The authors emphasize that any discussion of the optical behavior of small particles is inseparable from a full understanding of the optical behavior of the parent material-bulk matter. To divorce one concept from the other is to render any study on scattering theory seriously incomplete. Special features and important topics covered in this book include:. * Classical theor
Small angle scattering of X radiation and slow neutrons in structural analyses of amorphous solids
International Nuclear Information System (INIS)
Kostorz, G.
1980-01-01
Small angle scattering of x radiation and slow neutrons allows to detect inhomogeneities of the dimension of ten to some thousands of Angstroem by the difference in the scattering length density. The progress made during recent years in the development of apparatusses has created the possibility of solving very complicated problems. A first outline shows that in separation processes as well as in investigating extended defects the method of small angle scattering may provide valuable contributions to the analysis of the non-crystalline state
Time-reversal of electromagnetic scattering for small scatterer classification
International Nuclear Information System (INIS)
Smith, J Torquil; Berryman, James G
2012-01-01
Time-reversal operators, or the alternatively labelled, but equivalent, multistatic response matrix methods, are used to show how to determine the number of scatterers present in an electromagnetic scattering scenario that might be typical of UneXploded Ordinance (UXO) detection, classification and removal applications. Because the nature of the target UXO application differs from that of many other common inversion problems, emphasis is placed here on classification and enumeration rather than on detailed imaging. The main technical issues necessarily revolve around showing that it is possible to find a sufficient number of constraints via multiple measurements (i.e. using several distinct views at the target site) to solve the enumeration problem. The main results show that five measurements with antenna pairs are generally adequate to solve the classification and enumeration problems. However, these results also demonstrate a need for decreasing noise levels in the multistatic matrix as the number n of scatterers increases for the intended practical applications of the method. (paper)
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)
Verhaar, B.J.; de Goey, L.P.H.; Vredenbregt, E.J.D.
1985-01-01
The concepts of scattering length a and effective range r/sub e/ previously introduced for low-energy scattering from a potential V(r) in a plane and in higher dimensions are extended to include a 1/r potential (strength parameter γ). Both a and r/sub e/ have the physical significance of being equal to the radius of an equivalent hard sphere giving rise to the same O(k 0 ) and O(k 2 ) terms in the expression for the phase shift. The method used is based on the properties of the ''local scattering length'' a(r,γ) for the potential V(r) cut off at radius r and an ''equivalent hard-sphere radius'' a(r,k,γ) for wave number knot =0. It is shown that these quantities have a smooth behavior for γ→0 and for dimension n→2
Coulomb corrections to nuclear scattering lengths and effective ranges for weakly bound systems
International Nuclear Information System (INIS)
Mur, V.D.; Popov, V.S.; Sergeev, A.V.
1996-01-01
A procedure is considered for extracting the purely nuclear scattering length as and effective range rs (which correspond to a strong-interaction potential Vs with disregarded Coulomb interaction) from the experimentally determined nuclear quantities acs and rcs, which are modified by Coulomb interaction. The Coulomb renormalization of as and rs is especially strong if the system under study involves a level with energy close to zero (on the nuclear scale). This applies to formulas that determine the Coulomb renormalization of the low-energy parameters of s scattering (l=0). Detailed numerical calculations are performed for coefficients appearing in the equations that determine Coulomb corrections for various models of the potential Vs(r). This makes it possible to draw qualitative conclusions that the dependence of Coulomb corrections on the form of the strong-interaction potential and, in particular, on its small-distance behavior. A considerable enhancement of Coulomb corrections to the effective range rs is found for potentials with a barrier
Pairing-bag excitations in small-coherence-length superconductors
International Nuclear Information System (INIS)
Bishop, A.R.; Lomdahl, P.S.; Schrieffer, J.R.; Trugman, S.A.
1988-01-01
Localized baglike solutions in the pairing theory of superconductivity are studied. Starting from the Bogoliubov--de Gennes equations on a two-dimensional square lattice for half-filled negative-U Hubbard model, cigar- and star-shaped bags are numerically obtained, inside of which the order parameter is reduced, self-consistently trapping an added quasiparticle. These nonlinear excitations are important when the coherence length is small as for the new high-temperature superconductors. Several experimental consequences are discussed
DEFF Research Database (Denmark)
Sugiyama, Masaaki; Annaka, Masahiko; Hara, Kazuhiro
2003-01-01
Mesoscopic structures, with length scales similar to10(2) Angstrom, were investigated by small-angle X-ray and neutron scattering (SAXS and SANS) in several N-isopropylacrylamide-sodium acrylate (NIPA-SA) copolymeric hydrogels with varying [NIPA]/[SA] ratios and water contents. The SAXS experimen...
Progress in small angle neutron scattering activities in Malaysia
Energy Technology Data Exchange (ETDEWEB)
Mohamed, Abudl Aziz Bin [Industrial Technology Division, Malaysian Institute for Nuclear Technology Research (MINT) (Indonesia)
2000-10-01
Research activities by use of small angle neutron scattering in Malaysia are briefly reported. Scattered neutron data are displayed in two or three-dimensional isometric view by the data acquisition system. Visual Basic is utilized for data acquisition and MathCad for data processing and analyses. (Y. Kazumata)
Progress in small angle neutron scattering activities in Malaysia
International Nuclear Information System (INIS)
Mohamed, Abudl Aziz Bin
2000-01-01
Research activities by use of small angle neutron scattering in Malaysia are briefly reported. Scattered neutron data are displayed in two or three-dimensional isometric view by the data acquisition system. Visual Basic is utilized for data acquisition and MathCad for data processing and analyses. (Y. Kazumata)
Small angle X-ray scattering from hydrating tricalcium silicate
International Nuclear Information System (INIS)
Vollet, D.
1983-01-01
The small-angle X-ray scattering technique was used to study the structural evolution of hydrated tricalcium silicate at room temperature. The changes in specific area of the associated porosity and the evolution of density fluctuations in the solid hydrated phase were deduced from the scattering data. A correlation of these variations with the hydration mechanism is tried. (Author) [pt
Small-angle neutron scattering studies of sodium butyl benzene
Indian Academy of Sciences (India)
Na-NBBS), in aqueous solutions is investigated by small-angle neutron scattering (SANS). Nearly ellipsoidal aggregates of Na-NBBS at concentrations well above its minimum hydrotrope concentration were detected by SANS. The hydrotrope ...
Isospin breaking in the pion-nucleon coupling constant and the nucleon-nucleon scattering length
Directory of Open Access Journals (Sweden)
V. A. Babenko
2016-08-01
Full Text Available Charge independence breaking (CIB in the pion-nucleon coupling constant and the nucleon-nucleon scattering length is considered on the basis of the Yukawa meson theory. CIB effect in these quantities is almost entirely explained by the mass difference between the charged and the neutral pions. Therewith charge splitting of the pion-nucleon coupling constant is almost the same as charge splitting of the pion mass. Calculated difference between the proton-proton and the neutron-proton scattering length in this case comprises ∼90% of the experimental value.
Constant scattering length fits to low energy K-p interactions
International Nuclear Information System (INIS)
Conboy, J.E.
1985-10-01
The paper concerns the data on low energy K - p interactions analysed using the constant scattering length (C.S.L.) approximation. The scattering lengths are found to differ significantly from those required to fit data from previous K -1 p experiments, and these differences are discussed. The data indicate an Tspin=1 P- wave interaction, from the production angle distributions of the K-bar 0 n, Σ +- π -+ and Λπ 0 channels. However the authors have been unable to fit both the P-wave and K 0 sub(L)p data with the simple C.S.L. model. (U.K.)
Determination of the negatively charged pion-proton scattering length from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2003-01-01
We derive a closed, model independent, expression for the electromagnetic correction factor to the hadronic scattering length extracted from a hydrogenic atom with an extended charge and in the limit of a short ranged hadronic interaction to terms of order ((alpha)**2)(log(alpha)) in the limit of a non-relativistic approach. A hadronic negatively charged pion-proton scattering length of 0.0870(5), in units of inverse charged pion-mass, is deduced, leading to a pion-nucleon coupling constant from the GMO relation equals to 14.00(19).
A phenomenological determination of the pion-nucleon scattering lengths from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2005-01-01
A model independent expression for the electromagnetic corrections to a phenomenological hadronic pion-nucleon scattering length, extracted from pionic hydrogen, is obtained. In a non-relativistic approach and using an extended charge distribution, these corrections are derived up to terms of order (alpha)**2 log(alpha) in the limit of a short-range hadronic interaction. We infer a charged pion-proton scattering length of 0.0870(5) in units of inverse pion mass, which gives for the charged pion-proton-neutron coupling, through the GMO relation, a value of 14.04(17).
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
Energy Technology Data Exchange (ETDEWEB)
Baru, V. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Theoretical and Experimental Physics, B. Cheremushinskaya 25, 117218 Moscow (Russian Federation); Hanhart, C. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany); Hoferichter, M.; Kubis, B. [Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Nogga, A. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany); Phillips, D.R., E-mail: phillips@phy.ohiou.ed [Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institute of Nuclear and Particle Physics and Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States)
2011-01-03
We present a calculation of the {pi}{sup -}d scattering length with an accuracy of a few percent using chiral perturbation theory. For the first time isospin-violating corrections are included consistently. Using data on pionic deuterium and pionic hydrogen atoms, we extract the isoscalar and isovector pion-nucleon scattering lengths and obtain a{sup +}=(7.6{+-}3.1).10{sup -3}M{sub {pi}}{sup -1} and a{sup -}=(86.1{+-}0.9).10{sup -3}M{sub {pi}}{sup -1}. Via the Goldberger-Miyazawa-Oehme sum rule, this leads to a charged-pion-nucleon coupling constant g{sub c}{sup 2}/4{pi}=13.69{+-}0.20.
Disordered porous solids : from chord distributions to small angle scattering
Levitz, P.; Tchoubar, D.
1992-06-01
Disordered biphasic porous solids are examples of complex interfacial media. Small angle scattering strongly depends on the geometrical properties of the internal surface partitioning a porous system. Properties of the second derivative of the bulk autocorrelation function quantitatively defines the level of connection between the small angle scattering and the statistical properties of this interface. A tractable expression of this second derivative, involving the pore and the mass chord distribution functions, was proposed by Mering and Tchoubar (MT). Based on the present possibility to make a quantitative connection between imaging techniques and the small angle scattering, this paper tries to complete and to extend the MT approach. We first discuss how chord distribution functions can be used as fingerprints of the structural disorder. An explicit relation between the small angle scattering and these chord distributions is then proposed. In a third part, the application to different types of disorder is critically discussed and predictions are compared to available experimental data. Using image processing, we will consider three types of disorder : the long-range Debye randomness, the “ correlated " disorder with a special emphasis on the structure of a porous glass (the vycor), and, finally, complex structures where length scale invariance properties can be observed. Les solides poreux biphasiques sont des exemples de milieux interfaciaux complexes. La diffusion aux petits angles (SAS) dépend fortement des propriétés géométriques de l'interface partitionant le milieu poreux. Les propriétés de la dérivée seconde de la fonction d'autocorrélation de densité définit quantitativement le niveau de connection entre la diffusion aux petits angles et les caractéristiques statistiques de cette interface. Une expression utilisable de cette seconde dérivée, impliquant les distributions de cordes associées à la phase massique et au réseau de pores, fut
Quantum scattering in one-dimensional systems satisfying the minimal length uncertainty relation
Energy Technology Data Exchange (ETDEWEB)
Bernardo, Reginald Christian S., E-mail: rcbernardo@nip.upd.edu.ph; Esguerra, Jose Perico H., E-mail: jesguerra@nip.upd.edu.ph
2016-12-15
In quantum gravity theories, when the scattering energy is comparable to the Planck energy the Heisenberg uncertainty principle breaks down and is replaced by the minimal length uncertainty relation. In this paper, the consequences of the minimal length uncertainty relation on one-dimensional quantum scattering are studied using an approach involving a recently proposed second-order differential equation. An exact analytical expression for the tunneling probability through a locally-periodic rectangular potential barrier system is obtained. Results show that the existence of a non-zero minimal length uncertainty tends to shift the resonant tunneling energies to the positive direction. Scattering through a locally-periodic potential composed of double-rectangular potential barriers shows that the first band of resonant tunneling energies widens for minimal length cases when the double-rectangular potential barrier is symmetric but narrows down when the double-rectangular potential barrier is asymmetric. A numerical solution which exploits the use of Wronskians is used to calculate the transmission probabilities through the Pöschl–Teller well, Gaussian barrier, and double-Gaussian barrier. Results show that the probability of passage through the Pöschl–Teller well and Gaussian barrier is smaller in the minimal length cases compared to the non-minimal length case. For the double-Gaussian barrier, the probability of passage for energies that are more positive than the resonant tunneling energy is larger in the minimal length cases compared to the non-minimal length case. The approach is exact and applicable to many types of scattering potential.
Characterization of porous materials by small-angle scattering
Indian Academy of Sciences (India)
radiation is used in some cases to access large length scale and also to minimize the effect ... For numerous industrial and technological applications, it is often necessary to ... catalytic systems and gas burners require materials to be permeable and to provide ... We have estimated the scattering mean free path L, the.
Determination of the pion-nucleon coupling constant and scattering lengths
International Nuclear Information System (INIS)
Ericson, T.E.O.; Loiseau, B.; Thomas, A.W.
2002-01-01
We critically evaluate the isovector Goldberger-Miyazawa-Oehme (GMO) sum rule for forward πN scattering using the recent precision measurements of π - p and π - d scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data, g c 2 (GMO)/4π=14.11±0.05(statistical)±0.19(systematic) or f c 2 /4π=0.0783(11). This value is intermediate between that of indirect methods and the direct determination from backward np differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the pion-proton and pion-neutron scattering lengths with high precision, namely, (a π - p +a π - n )/2=[-12±2(statistical)±8(systematic)]x10 -4 m π -1 and (a π - p -a π - n )/2=[895±3(statistical)±13 (systematic)]x10 -4 m π -1 . For the need of the present analysis, we improve the theoretical description of the pion-deuteron scattering length
Small-angle neutron scattering at pulsed spallation sources
International Nuclear Information System (INIS)
Seeger, P.A.; Hjelm, R.P. Jr.
1990-01-01
The importance of small-angle neutron scattering (SANS) in biological, chemical, physical, and engineering research mandates that all intense neutron sources be equipped with SANS instruments. Four existing instruments are described, and the general differences between pulsed-source and reactor-based instrument designs are discussed. The basic geometries are identical, but dynamic range is achieved by using a broad band of wavelengths (with time-of-flight analysis) rather than by moving the detector. This allows a more optimized collimation system. Data acquisition requirements at a pulsed source are more severe, requiring large, fast histogramming memories. Data reduction is also more complex, as all wave length-dependent and angle-dependent backgrounds and non-linearities must be accounted for before data can be transformed to intensity vs Q. A comparison is shown between the Los Alamos pulsed instrument and D-11 (Institute Laue-Langevin), and examples from the four major topics of the conference are shown. The general conclusion is that reactor-based instruments remain superior at very low Q or if only a narrow range of Q is required, but that the current generation of pulsed-source instruments is competitive at moderate Q and may be faster when a wide range of Q is required. In principle, a user should choose which facility to use on the basis of optimizing the experiment; in practice the tradeoffs are not severe and the choice is usually made on the basis of availability
Mass and scattering length inequalities in QCD and QCD-like theories
International Nuclear Information System (INIS)
Nussinov, S.; Pennsylvania Univ., Philadelphia; Sathiapalan, B.
1985-01-01
Some observations about mass scattering length inequalities in QCD-like theories are presented. It is shown that the Weingarten mass inequality can be used to argue that global vector symmetries are unbroken in such theories. For QCD, in the limit Nsub(c)->infinite, it is shown that Msub(baryon)>=1/2Nsub(c)Msub(meson), provided there are at least Nsub(c) degenerate flavors of quarks. It is argued that when there are not bound states in a scattering channel, the mass inequalities can be used to derive inequalities beteen scattering lengths. Some rigorous inequalities for two and higher point functions for operators bilinear in currents are derived, and used to extract inequalities between quartic coupling constants. (orig.)
A rigorous phenomenological analysis of the ππ scattering lengths
International Nuclear Information System (INIS)
Caprini, I.; Dita, P.; Sararu, M.
1979-11-01
The constraining power of the present experimental data, combined with the general theoretical knowledge about ππ scattering, upon the scattering lengths of this process, is investigated by means of a rigorous functional method. We take as input the experimental phase shifts and make no hypotheses about the high energy behaviour of the amplitudes, using only absolute bounds derived from axiomatic field theory and exact consequences of crossing symmetry. In the simplest application of the method, involving only the π 0 π 0 S-wave, we explored numerically a number of values proposed by various authors for the scattering lengths a 0 and a 2 and found that no one appears to be especially favoured. (author)
Ultra-small-angle neutron scattering. History, developments and applications
International Nuclear Information System (INIS)
Koizumi, Satoshi; Yamaguchi, Daisuke
2011-01-01
Ultra-small-angle neutron scattering (USANS), which is a scattering method observing in a q-region of q=10 -3 nm -1 , was initiated by double crystal (Bonse-Hart) method. Recently, a focusing USANS method was developed by combining a pin-hole type spectrometer and focusing lenses. These two methods, which are complementary to each other, were employed to achieve wide q-observations on microbial cellulose, actin cytoskeleton, tire, and membrane-electrolyte assembly of fuel cell. (author)
Small-angle X-ray scattering of solutions
International Nuclear Information System (INIS)
Koch, M.H.J.; Stuhrmann, H.B.; Vachette, P.; Tardieu, A.
1982-01-01
The use of synchrotron radiation in small-angle X-ray scattering (SAXS) techniques in biological structural studies is described. The main features of the monochromatic radiation systems and the white radiation systems are considered. The detectors, data acquisition and experimental procedures are briefly described. Experimental results are presented for 1) measurements on dilute solutions and weak scatterers, 2) measurement of conformational transitions, 3) contrast variation experiments, 4) time-resolved measurements and 5) complex contrast variation. (U.K.)
Small angle neutron scattering from hydrated cement pastes
International Nuclear Information System (INIS)
Sabine, T.M.; Bertram, W.K.; Aldridge, L.P.
1996-01-01
Small angle neutron scattering (SANS) was used to study the microstructure of hydrating cement made with, and without silica fume. Some significant differences were found between the SANS spectra of pastes made from OPC (ordinary Portland cement) and DSP (made with silica fume and superplasticiser). The SANS spectra are interpreted in terms of scattering from simple particles. Particle growth was monitored during hydration and it was found that the growth correlated with the heat of hydration of the cement
SWIMS: a small-angle multiple scattering computer code
International Nuclear Information System (INIS)
Sayer, R.O.
1976-07-01
SWIMS (Sigmund and WInterbon Multiple Scattering) is a computer code for calculation of the angular dispersion of ion beams that undergo small-angle, incoherent multiple scattering by gaseous or solid media. The code uses the tabulated angular distributions of Sigmund and Winterbon for a Thomas-Fermi screened Coulomb potential. The fraction of the incident beam scattered into a cone defined by the polar angle α is computed as a function of α for reduced thicknesses over the range 0.01 less than or equal to tau less than or equal to 10.0. 1 figure, 2 tables
Small angle x-ray scattering from proteins in solution
International Nuclear Information System (INIS)
de Souza, C.F.; Torriani, I.L.; Bonafe, C.F.S.; Merrelles, N.C.; Vachette, P.
1989-01-01
In this work the authors report experiments performed with giant respiratory proteins from annelids (erythrocruorins), known to have a molecular weight in the order of four million Daltons. Preliminary x-ray scattering data was obtained using a conventional rotating anode source. High resolution small angle scattering curves were obtained with synchrotron radiation from the DCI storage ring at LURE. Data from solutions with several protein concentrations were analyzed in order to determine low resolution dimensional parameters, using Guinier plots from the smeared scattering curves and the inverse transformation method
ρ, ω, and φ meson-nucleon scattering lengths from QCD sum rules
International Nuclear Information System (INIS)
Koike, Y.
1995-01-01
The QCD sum rule method is applied to derive a formula for the ρ, ω, and φ meson-nucleon spin-isospin--averaged scattering lengths a ρ,ω,φ . We found that the crucial matrix elements are left-angle bar qγ μ D ν q right-angle N (q=ud) (twist-2 nucleon matrix element) for a ρ,ω and m s left-angle bar ss right-angle N for a φ , and obtained a ρ =0.14±0.07 fm, a ω =0.11±0.06 fm, and a φ =0.035±0.020 fm. These small numbers originate from a common factor 1/(m N +m ρ,ω,φ ). Our result suggests a slight increase (<60 MeV for ρ and ω, and <15 MeV for φ) of the effective mass of these vector mesons in nuclear matter (in the dilute nucleon-gas approximation). The origin of the discrepancy with Hatsuda-Lee was clarified
Small-angle neutron scattering in materials science
International Nuclear Information System (INIS)
Fratzl, P.
1999-01-01
Small-angle scattering (SAS) in an ideal tool for studying the structure of materials in the mesoscopic size range between 1 and about 100 nanometers. The basic principles of the method are reviewed, with particular emphasis on data evaluation and interpretation for isotropic as well as oriented or single-crystalline materials. Examples include metal alloys, composites and porous materials. The last section gives a comparison between the use of neutrons and (synchrotron) x-rays for small-angle scattering in materials physics. (author)
Small angle elastic scattering of electrons by noble gas atoms
International Nuclear Information System (INIS)
Wagenaar, R.W.
1984-01-01
In this thesis, measurements are carried out to obtain small angle elastic differential cross sections in order to check the validity of Kramers-Kronig dispersion relations for electrons scattered by noble gas atoms. First, total cross sections are obtained for argon, krypton and xenon. Next, a parallel plate electrostatic energy analyser for the simultaneous measurement of doubly differential cross section for small angle electron scattering is described. Also absolute differential cross sections are reported. Finally the forward dispersion relation for electron-helium collisions is dealt with. (Auth.)
Isotope effects in complex scattering lengths for He collisions with molecular hydrogen
International Nuclear Information System (INIS)
Nolte, J. L.; Yang, B. H.; Stancil, P. C.; Lee, Teck-Ghee; Balakrishnan, N.; Forrey, R. C.; Dalgarno, A.
2010-01-01
We examine the effect of theoretically varying the collision-system reduced mass in collisions of He with vibrationally excited molecular hydrogen and observe zero-energy resonances for select atomic 'hydrogen' masses less than 1 u or a 'helium' mass of 1.95 u. Complex scattering lengths, state-to-state vibrational quenching cross sections, and a low-energy elastic scattering resonance are all studied as a function of collision-system reduced mass. Experimental observations of these phenomena in the cold and ultracold regimes for collisions of 3 He and 4 He with H 2 , HD, HT, and DT should be feasible in the near future.
Determination of nn scattering length from data on nn final state interaction in nd-breakup reaction
International Nuclear Information System (INIS)
Konobeevski, E.S.; Mordovskoy, M.V.; Sergeev, V.A.; Potashev, S.I.; Zuev, S.V.
2006-01-01
Full text: An experiment is proposed for the high-precision determination of the neutron-neutron scattering length investigating the nn final state interaction in the nd breakup reaction. The singlet pp and nn scattering lengths are very sensitive probes of the NN-interaction, and their difference is a direct measure of charge-symmetry breaking (CSB) of the nuclear force. However CSB is a small effect, and accurate values of the scattering lengths are needed for a theoretical analysis. The proton-proton scattering length is well known from pp-scattering data (a pp = -17.3± 0.4 fm), and its uncertainty is mainly due to a model-dependent procedure of removing Coulomb effects. The neutron-neutron scattering length is determined from the following processes n+d→p+n+n, π - + d → γ +n+n, d+d→ 2 He+n+n by investigating the kinematic region of the nn final-state interaction (FSI) where two neutrons fly with low relative energy. The results obtained by now are characterized by a significant uncertainty in values of a nn ; they are grouped near -16 and -19 fm [1,2], so even the sign of the difference a nn - a pp is uncertain. In this experiment neutron-neutron scattering length is determined by measuring the yield of the nd breakup reaction as a function of the relative energy ε nn =(E 1 +E 2 -2(E 1 E 2 ) 1/2 cosθ)/2 of two neutrons in the FSI region (two neutrons fly in a narrow angular cone) where nn-interaction is strongly revealed. The theory of reactions in 3N system predicts the ε nn dependence of the FSI cross section being sensitive to the value of a nn . The measurements will be made using the neutron channel RADEX at Moscow meson factory of the Institute for Nuclear Research. The momenta and angles of the two emitted neutrons and the energy of the proton will be measured for each breakup event. The measured dependence of the reaction yield on the relative energy of the two neutrons will be compared to results of the Monte Carlo simulation that includes
QCD expectations for deep inelastic scattering at small x
International Nuclear Information System (INIS)
Kwiecinski, J.
1993-01-01
The basic QCD expectations concerning the deep inelastic scattering at low x where x is the Bjorken scaling variable are reviewed. This includes discussion of the Lipatov equation which sums the leading powers of Ln(1/x) and the shadowing effects. Phenomenological implications of the theoretical expectations for the deep inelastic lepton-hadron scattering in the small x region which will be accessible at the HERA ep collider are described. We give predictions for structure functions F 2 and F L based on the k T factorization theorem and discuss jet production in deep inelastic lepton scattering. The list of other topical problems relevant for the small x physics is given. (author). 46 refs, 7 figs
Small angle neutron scattering investigations of spin disorder in nanocomposite soft magnets
International Nuclear Information System (INIS)
Vecchini, C.; Moze, O.; Suzuki, K.; Cadogan, J.M.; Pranzas, K.; Michels, A.; Weissmueller, J.
2006-01-01
The technique of SANS (small angle neutron scattering) furnishes unique information on the characteristic magnetic length scales and local magnetic anisotropies at the nanoscale in nanocomposite ferromagnets. Such information is not presently available using any other microscopic technique. The basic principles and results of the technique will be presented with regard to a unique and unexpected observation of a dipole field controlled spin disorder in a prototypical soft nanocomposite ferromagnet of the Nanoperm type
Ericson, Torleif Eric Oskar; Thomas, A W
2000-01-01
We critically evaluate the isovector GMO sumrule for the charged $\\pi N N$ coupling constant using recent precision data from $\\pi ^-$p and $\\pi^-$d atoms and with careful attention to systematic errors. From the $\\pi ^-$d scattering length we deduce the pion-proton scattering lengths ${1/2}(a_{\\pi ^-p}+a_{\\pi ^-n})=(-20\\pm 6$(statistic)$ \\pm 10$ (systematic))~$\\cdot 10^{-4}m_{\\pi_c}^{-1}$ and ${1/2}(a_{\\pi ^-p}-a_{\\pi ^-n})=(903 \\pm 14)\\cdot 10^{-4}m_{\\pi_c}^{-1}$. From this a direct evaluation gives $g^2_c(GMO) =14.20\\pm 0.07$(statistic)$\\pm 0.13$(systematic) or $f^2_c= 0.0786\\pm 0.0008$.
A phenomenological {pi}{sup -}p scattering length from pionic hydrogen
Energy Technology Data Exchange (ETDEWEB)
Ericson, T.E.O.; Loiseau, B.; Wycech, S
2004-07-29
We derive a closed, model independent, expression for the electromagnetic correction factor to a phenomenological hadronic scattering length a{sup h} extracted from a hydrogenic atom. It is obtained in a non-relativistic approach and in the limit of a short ranged hadronic interaction to terms of order {alpha}{sup 2}log{alpha} using an extended charge distribution. A hadronic {pi}N scattering length a{sup h}{sub {pi}{sup -}}{sub p}=0.0870(5)m{sub {pi}}{sup -1} is deduced leading to a {pi}NN coupling constant from the GMO relation g{sub c}{sup 2}/(4{pi})=14.04(17)
The {pi}{sup +}{pi}{sup +} scattering length from maximally twisted mass lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Feng, Xu [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Jansen, Karl; Renner, Dru [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2009-12-15
We calculate the s-wave pion-pion scattering length in the isospin I=2 channel in lattice QCD for pion masses ranging from 270 Mev to 485 Mev using two flavors of maximally twisted mass fermions at a lattice spacing of 0.086 fm. Additionally, we check for lattice artifacts with one calculation at a finer lattice spacing of 0.067 fm. We use chiral perturbation theory at next-to-leading order to extrapolate our results. At the physical pion mass, we find m{sub {pi}}a{sup I=2}{sub {pi}}{sub {pi}}=-0.04385(28)(38) for the scattering length, where the first error is statistical and the second is our estimate of several systematic effects. (orig.)
Small angle neutron scattering studies of mixed micelles of sodium
Indian Academy of Sciences (India)
The aqueous solutions of sodium cumene sulphonate (NaCS) and its mixtures with each of cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) are characterized by small angle neutron scattering (SANS). NaCS when added to CTAB solution leads to the formation of long rod-shaped micelles with ...
Spin-Echo Small-Angle Neutron Scattering Development
Uca, O.
2003-01-01
Spin-Echo Small-Angle Neutron Scattering (SESANS) instrument is a novel SANS technique which enables one to characterize distances from a few nanometers up to the micron range. The most striking difference between normal SANS and SESANS is that in SESANS one gets information in real space, whereas
Small-angle neutron scattering studies on water soluble complexes ...
Indian Academy of Sciences (India)
... by small-angle neutron scattering. SANS data showed a positive indication of the formation of RCP-SDS complexes. Even though the complete structure of the polyion complexes could not be ascertained, the results obtained give us the information on the local structure in these polymer-surfactant systems. The data were ...
Small Angle Neutron Scattering instrument at Malaysian TRIGA reactor
Energy Technology Data Exchange (ETDEWEB)
Mohd, Shukri; Kassim, Razali; Mahmood, Zal Uyun [Malaysian Inst. for Nuclear Technology Research (MINT), Bangi, Kajang (Malaysia); Radiman, Shahidan
1998-10-01
The TRIGA MARK II Research reactor at the Malaysian Institute for Nuclear Research (MINT) was commissioned in July 1982. Since then various works have been performed to utilise the neutrons produced from this steady state reactor. One of the project involved the Small Angle Neutron Scattering (SANS). (author)
Characterization of alumina using small angle neutron scattering (SANS)
International Nuclear Information System (INIS)
Megat Harun Al Rashidn Megat Ahmad; Abdul Aziz Mohamed; Azmi Ibrahim; Che Seman Mahmood; Edy Giri Rachman Putra; Muhammad Rawi Muhammad Zin; Razali Kassim; Rafhayudi Jamro
2007-01-01
Alumina powder was synthesized from an aluminium precursor and studied using small angle neutron scattering (SANS) technique and complemented with transmission electron microscope (TEM). XRD measurement confirmed that the alumina produced was high purity and highly crystalline αphase. SANS examination indicates the formation of mass fractals microstructures with fractal dimension of about 2.8 on the alumina powder. (Author)
Progress in small angle neutron scattering activities in Malaysia
International Nuclear Information System (INIS)
Abdul Aziz Bin Mohamed; Azali Bin Muhamad; Shukri Bin Mohd
1999-01-01
The current status of SANS (Small Angle Neutron Scattering facility) activities in Malaysia has been presented. Many works need to be done for system improvement before the system can be confidently used as one of effective quality control tools in materials production and engineering sectors. (author)
Small angle neutron scattering studies on the interaction of cationic
Indian Academy of Sciences (India)
The structure of the protein–surfactant complex of bovine serum albumin (BSA) and cationic surfactants has been studied by small angle neutron scattering. At low concentrations, the CTAB monomers are observed to bind to the protein leading to an increase in its size. On the other hand at high concentrations, surfactant ...
Small-angle neutron scattering studies of nonionic surfactant: Effect
Indian Academy of Sciences (India)
Micellar solution of nonionic surfactant -dodecyloligo ethyleneoxide surfactant, decaoxyethylene monododecyl ether [CH3(CH2)11(OCH2CH2)10OH], C12E10 in D2O solution have been analysed by small-angle neutron scattering (SANS) at different temperatures (30, 45 and 60°C) both in the presence and absence of ...
Small-angle neutron scattering in materials science - an introduction
International Nuclear Information System (INIS)
Fratzl, P.
1996-01-01
The basic principles of the application of small-angle neutron scattering to materials research are summarized. The text focusses on the classical methods of data evaluation for isotropic and for anisotropic materials. Some examples of applications to the study of alloys, porous materials, composites and other complex materials are given. (author) 9 figs., 38 refs
Small-angle neutron scattering from colloidal dispersions
International Nuclear Information System (INIS)
Ottewill, R.H.
1991-01-01
A survey is given of recent work on the use of small-angle neutron scattering to examine colloidal dispersions. Particular attention is given to the determination of particle size and polydispersity, the determination of particle morphology and the behaviour of concentrated colloidal dispersions, both at rest and under the influence of an applied shear field. (orig.)
Xiao, Jingwen; Liu, Fang; Garamus, Vasil M; Almásy, László; Handge, Ulrich A; Willumeit, Regine; Mu, Bozhong; Zou, Aihua
2014-04-01
The interactions among neutral polymer polyacrylamide (PAM) and the biosurfactant Surfactin and four betaines, N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SDDAB), N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (STDAB), N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SHDAB), and N-dodecyl-N,N-dimethyl-2-ammonio-acetate (C12BE), in phosphate buffer solution (PBS) have been studied by surface tension measurements, small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and rheological experiments. It has been confirmed that the length of alkyl chain is a key parameter of interaction between betaines and PAM. Differences in scattering contrast between X-ray and neutrons for surfactants and PAM molecules provide the opportunity to separately follow the changes of structure of PAM and surfactant aggregates. At concentrations of betaines higher than CMC (critical micelle concentration) and C2 (CMC of surfactant with the presence of polymer), spherical micelles are formed in betaines and betaines/PAM solutions. Transition from spherical to rod-like aggregates (micelles) has been observed in solutions of Surfactin and Surfactin/SDDAB (αSurfactin = 0.67 (molar fraction)) with addition of 0.8 wt % of PAM. The conformation change of PAM molecules only can be observed for Surfactin/SDDAB/PAM system. Viscosity values follow the structural changes suggested from scattering measurements i.e., gradually increases for mixtures PAM → Surfactin/PAM → Surfactin/SDDAB/PAM in PBS.
Trotter, D. E. Gonzalez; Salinas, F.; Chen, Q.; Crowell, A. S.; Gloeckle, W.; Howell, C. R.; Roper, C. D.; Schmidt, D.; Slaus, I.; Tang, H.; Tornow, W.; Walter, R. L.; Witala, H.; Zhou, Z.
1999-01-01
The present paper reports high-accuracy cross-section data for the 2H(n,nnp) reaction in the neutron-proton (np) and neutron-neutron (nn) final-state-interaction (FSI) regions at an incident mean neutron energy of 13.0 MeV. These data were analyzed with rigorous three-nucleon calculations to determine the 1S0 np and nn scattering lengths, a_np and a_nn. Our results are a_nn = -18.7 +/- 0.6 fm and a_np = -23.5 +/- 0.8 fm. Since our value for a_np obtained from neutron-deuteron (nd) breakup agr...
Determination of ππ scattering lengths from measurement of π+π- atom lifetime
International Nuclear Information System (INIS)
Adeva, B.; Afanasyev, L.; Benayoun, M.; Benelli, A.; Berka, Z.; Brekhovskikh, V.; Caragheorgheopol, G.; Cechak, T.; Chiba, M.; Chliapnikov, P.V.; Ciocarlan, C.; Constantinescu, S.; Costantini, S.; Curceanu, C.; Doskarova, P.; Dreossi, D.; Drijard, D.; Dudarev, A.; Ferro-Luzzi, M.; Fungueirino Pazos, J.L.
2011-01-01
The DIRAC experiment at CERN has achieved a sizeable production of π + π - atoms and has significantly improved the precision on its lifetime determination. From a sample of 21 227 atomic pairs, a 4% measurement of the S-wave ππ scattering length difference |a 0 -a 2 |=(0.2533 -0.0078 +0.0080 | stat +0.0078 -0.0073 | syst )M π + -1 has been attained, providing an important test of Chiral Perturbation Theory.
Determination of the pion-nucleon coupling constant and scattering lengths
Ericson, Torleif Eric Oskar; Thomas, A W
2002-01-01
We critically evaluate the isovector GMO sum rule for forward pion-nucleon scattering using the recent precision measurements of negatively charged pion-proton and pion-deuteron scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data a pseudoscalar coupling constant of 14.17+-0.05(statistical)+-0.19(systematic) or a pseudovector one of 0.0786(11). This value is intermediate between that of indirect methods and the direct determination from backward neutron-proton differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the negatively charged pion-proton and pion-neutron scattering lengths with high precision. The symmetric sum gives 0.0017+-0.0002(statistical)+-0.0008 (systematic) and the antisymmetric one 0.0900+-0.0003(statistical)+-0.0013(systematic), both in units of inverse charged pi...
Study of chemically unfolded {beta}-casein by means of small-angle neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Aschi, Adel [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 1060, Tunis (Tunisia)]. E-mail: aschi13@yahoo.fr; Gharbi, Abdelhafidh [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 1060, Tunis (Tunisia); Daoud, Mohamed [Service de Physique de l' Etat Condense. CEA Saclay. 91191 Gif-sur-Yvette cedex (France); Douillard, Roger [Equipe de Biochimie des Macromolecules Vegetales, Centre de Recherche Agronomique, 2Esplanade R. Garros, BP 224, 51686 Reims cedex 2 (France); Calmettes, Patrick [Laboratoire Leon Brillouin, CEA Saclay, 91191 Gif-sur-Yvette cedex (France)
2007-01-01
{beta}-casein is a flexible amphiphilic milk protein which forms an unfolded conformation in presence of very high denaturant concentrations. The structure of {beta}-casein formed at the bulk was studied by small-angle neutron scattering (SANS). The value of the second virial coefficient of the protein solutions indicates that the interactions between the polypeptide chain and solvent are repulsive. The protein conformation is similar to an excluded volume chain. The corresponding values of the contour length, L, the statistical length, b and the apparent radius of the chain cross-section, R{sub c} are given.
Ion track annealing in quartz investigated by small angle X-ray scattering
Energy Technology Data Exchange (ETDEWEB)
Schauries, D.; Afra, B.; Rodriguez, M.D. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601 (Australia); Trautmann, C. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Technische Universität Darmstadt, 64287 Darmstadt (Germany); Hawley, A. [Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168 (Australia); Kluth, P. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601 (Australia)
2015-12-15
We report on the reduction of cross-section and length of amorphous ion tracks embedded within crystalline quartz during thermal annealing. The ion tracks were created via Au ion irradiation with an energy of 2.2 GeV. The use of synchrotron-based small angle X-ray scattering (SAXS) allowed characterization of the latent tracks, without the need for chemical etching. Temperatures between 900 and 1000 °C were required to see a notable change in track size. The shrinkage in cross-section and length was found to be comparable for tracks aligned perpendicular and parallel to the c-axis.
Study of chemically unfolded β-casein by means of small-angle neutron scattering
International Nuclear Information System (INIS)
Aschi, Adel; Gharbi, Abdelhafidh; Daoud, Mohamed; Douillard, Roger; Calmettes, Patrick
2007-01-01
β-casein is a flexible amphiphilic milk protein which forms an unfolded conformation in presence of very high denaturant concentrations. The structure of β-casein formed at the bulk was studied by small-angle neutron scattering (SANS). The value of the second virial coefficient of the protein solutions indicates that the interactions between the polypeptide chain and solvent are repulsive. The protein conformation is similar to an excluded volume chain. The corresponding values of the contour length, L, the statistical length, b and the apparent radius of the chain cross-section, R c are given
A multi-dimensional sampling method for locating small scatterers
International Nuclear Information System (INIS)
Song, Rencheng; Zhong, Yu; Chen, Xudong
2012-01-01
A multiple signal classification (MUSIC)-like multi-dimensional sampling method (MDSM) is introduced to locate small three-dimensional scatterers using electromagnetic waves. The indicator is built with the most stable part of signal subspace of the multi-static response matrix on a set of combinatorial sampling nodes inside the domain of interest. It has two main advantages compared to the conventional MUSIC methods. First, the MDSM is more robust against noise. Second, it can work with a single incidence even for multi-scatterers. Numerical simulations are presented to show the good performance of the proposed method. (paper)
Raman and fluorescent scattering by molecules embedded in small particles
International Nuclear Information System (INIS)
Chew, H.W.; McNulty, P.J.
1983-01-01
We have formulated a model for fluorescent and Raman scattering by molecules embedded in or in the vicinity of small particles. The model takes into account the size, shape, refractive index, and morphology of the host particles. Analytic and numerical results have been obtained for spherical (one and more layers, including magnetic dipole transitions) cylindrical and spheroidal particles. Particular attention has been given to the spherical case with fluorescent/Raman scatterers uniformly distributed in the particles radiating both coherently and incohorently. Depolarization effects have been studied with suitable averaging process, and good agreement with experiment has been obtained. Analytic and numerical results have been obtained for the elastic scattering of evanescent waves; these results are useful for the study of fluorescent under excitation by evanescent waves
MUSIC-characterization of small scatterers for normal measurement data
Griesmaier, Roland; Hanke, Martin
2009-07-01
We investigate the reconstruction of the positions of a collection of small metallic objects buried beneath the ground from measurements of the vertical component of scattered fields corresponding to vertically polarized dipole excitations on a horizontal two-dimensional measurement device above the surface of the ground. A MUSIC reconstruction method for this problem has recently been proposed by Iakovleva et al (2007 IEEE Trans. Antennas Propag. 55 2598). In this paper, we give a rigorous theoretical justification of this method. To that end we prove a characterization of the positions of the scatterers in terms of the measurement data, applying an asymptotic analysis of the scattered fields. We present numerical results to illustrate our theoretical findings.
MUSIC-characterization of small scatterers for normal measurement data
International Nuclear Information System (INIS)
Griesmaier, Roland; Hanke, Martin
2009-01-01
We investigate the reconstruction of the positions of a collection of small metallic objects buried beneath the ground from measurements of the vertical component of scattered fields corresponding to vertically polarized dipole excitations on a horizontal two-dimensional measurement device above the surface of the ground. A MUSIC reconstruction method for this problem has recently been proposed by Iakovleva et al (2007 IEEE Trans. Antennas Propag. 55 2598). In this paper, we give a rigorous theoretical justification of this method. To that end we prove a characterization of the positions of the scatterers in terms of the measurement data, applying an asymptotic analysis of the scattered fields. We present numerical results to illustrate our theoretical findings
Mao, Yimin; Liu, Kai; Zhan, Chengbo; Geng, Lihong; Chu, Benjamin; Hsiao, Benjamin S
2017-02-16
Nanocellulose extracted from wood pulps using TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and sulfuric acid hydrolysis methods was characterized by small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and dynamic light scattering (DLS) techniques. The dimensions of this nanocellulose (TEMPO-oxidized cellulose nanofiber (TOCN) and sulfuric acid hydrolyzed cellulose nanocrystal (SACN)) revealed by the different scattering methods were compared with those characterized by transmission electron microscopy (TEM). The SANS and SAXS data were analyzed using a parallelepiped-based form factor. The width and thickness of the nanocellulose cross section were ∼8 and ∼2 nm for TOCN and ∼20 and ∼3 nm for SACN, respectively, where the fitting results from SANS and SAXS profiles were consistent with each other. DLS was carried out under both the V V mode with the polarizer and analyzer parallel to each other and the H V mode having them perpendicular to each other. Using rotational and translational diffusion coefficients obtained under the H V mode yielded a nanocellulose length qualitatively consistent with that observed by TEM, whereas the length derived by the translational diffusion coefficient under the V V mode appeared to be overestimated.
On Small-Angle Neutron Scattering from Microemulsion Droplets the Role of Shape Fluctuations
Lisy, V
2001-01-01
The form factor and intensity of static neutron scattering from microemulsion droplets are calculated. The droplet is modeled by a double-layered sphere consisting of a fluid core and a thin surfactant layer, immersed in another fluid. All the three components are incompressible and characterized by different scattering length densities. As distinct from previous descriptions of small-angle neutron scattering (SANS), we consistently take into account thermal fluctuations of the droplet shape, to the second order of the fluctuations of the droplet radius. The properties of the layer are described within Helfrich's concept of the elasticity of curved interfaces. It is shown that in many cases the account for the fluctuations is essential for the interpretation of SANS. Information about two elastic constants \\kappa and \\bar\\kappa (so far extracted from the experiments in the combination 2\\kappa+\\bar\\kappa) can be now simultaneously obtained from SANS for system in conditions of two-phase coexistence. As an illu...
Time-resolved small-angle neutron scattering of a micelle-to-vesicle transition
Energy Technology Data Exchange (ETDEWEB)
Egelhaaf, S U [Institut Max von Laue - Paul Langevin (ILL), 38 -Grenoble (France); Schurtenberger, P [Eidgenoessische Technische Hochschule, Zurich (Switzerland)
1997-04-01
Amphiphilic molecules spontaneously self-assemble in solution to form a variety of aggregates. Only limited information is available on the kinetics of the structural transitions as well as on the existence of non-equilibrium or metastable states. Aqueous mixtures of lecithin and bile salt are very interesting biological model-systems which exhibit a spontaneous transition from polymer-like mixed micelles to vesicles upon dilution. The small-angle neutron scattering (SANS) instrument D22, with its very high neutron flux and the broad range of scattering vectors covered in a single instrumental setting, allowed us for the first time to perform time-resolved scattering experiments in order to study the micelle-to-vesicle transition. The temporal evolution of the aggregate structures were followed and detailed information was obtained even on molecular length-scales. (author). 5 refs.
Small angle neutron scattering using a triple axis spectrometer
International Nuclear Information System (INIS)
Ahmed, F.U.; Goyal, P.S.; Kamal, L.; Yunus, S.M.; Datta, T.K.; Rahman, M.O.; Azad, A.K.; Begum, S.; Zakaria, A.K.
1994-01-01
SANS techniques has been developed on a triple axis neutron spectrometer at TRIGA Mark II (3 MW) research reactor, AERE, Savar, Dhaka, Bangladesh. Double crystal (with very small mosaic spread ∼ 1 min.) diffraction known as Bonse and Hart's method has been employed. Such a device is a useful tool for small angle scattering in the Q range between 10 -5 and 10 -1 Angstroms -1 and for real time experiments at short time scales. Therefore, large objects and large distance interparticle correlations can be easily investigated. The results of SANS' measurements using alumina (A1 2 0 3 ) sample are presented. The radius of gyration has been determined and the data has been fitted to the scattering function of a sphere. 9 refs., 6 figs.,
Small Angle Neutron Scattering From Iron. Vol. 2
Energy Technology Data Exchange (ETDEWEB)
Adib, M; Abdel-Kawy, A; Naguib, K; Habib, N; Kilany, M [Reactor and Neutron Physics Dept., Nuclear Research Centre, AEA, Cairo, (Egypt); Wahba, M [Faculty of Engineering, ain Shams University, Cairo, (Egypt); Ashry, A [Faculty of Education, Ain Shams University, Cairo, (Egypt)
1996-03-01
The total neutron cross-section measurements have been carried out for iron in both metallic and powder forms in the wavelengths band 0.35 nm to 0.52 nm. The measurements were performed using the TOF spectrometer installed in front of one of the horizontal channels of the ET-RR-1 reactor. The observed behavior for the small-angle neutron scattering cross-section of iron powder was analyzed in terms of its particle diameter, incident neutron wavelength and beam divergence. It was found that for iron particles of diameter 25 {mu}m the small-angle neutron scattering is only due to refraction of neutron wave traversing the particles. A method was established to determine the particle size of iron powders within an accuracy of 8% which is higher than that obtained by mesh analysis. 4 figs., 1 tab.
Deeply inelastic scattering at small x in 20 min
International Nuclear Information System (INIS)
Levin, E.M.
1992-01-01
A status report is presented on new phenomena that are anticipated in deeply inelastic scattering in the low x→0 region. A summary of the theoretical situation in the region of small x is given, including the importance for the understanding of high energy interaction in QCD, and the low x behaviour of deep inelastic structure function. This new area of physics will be studied experimentally at HERA. (R.P.) 16 refs.; 6 figs
LeBlanc, Serge Emile; Atanya, Monica; Burns, Kevin; Munger, Rejean
2011-04-21
It is well known that red blood cell scattering has an impact on whole blood oximetry as well as in vivo retinal oxygen saturation measurements. The goal of this study was to quantify the impact of small angle forward scatter on whole blood oximetry for scattering angles found in retinal oximetry light paths. Transmittance spectra of whole blood were measured in two different experimental setups: one that included small angle scatter in the transmitted signal and one that measured the transmitted signal only, at absorbance path lengths of 25, 50, 100, 250 and 500 µm. Oxygen saturation was determined by multiple linear regression in the 520-600 nm wavelength range and compared between path lengths and experimental setups. Mean calculated oxygen saturation differences between setups were greater than 10% at every absorbance path length. The deviations to the Beer-Lambert absorbance model had different spectral dependences between experimental setups, with the highest deviations found in the 520-540 nm range when scatter was added to the transmitted signal. These results are consistent with other models of forward scatter that predict different spectral dependences of the red blood cell scattering cross-section and haemoglobin extinction coefficients in this wavelength range.
Effect of scatter media on small gamma camera imaging characteristics
International Nuclear Information System (INIS)
Ser, H. K.; Choi, Y.; Yim, K. C.
2001-01-01
Effect of scatter media materials and thickness, located between radioactivity and small gamma camera, on imaging characteristics was evaluated. The small gamma camera developed for breast imaging was consisted of collimator, NaI(TI) crystal (60x60x6 mm 3 ). PSPMT (position sensitive photomultiplier tube), NIMs and personal computer. Monte Carlo simulation was performed to evaluate the system sensitivity with different scatter media thickness (0∼8 cm) and materials (air and acrylie) with parallel hole collimator and diverging collimator. The sensitivity and spatial resolution was measured using the small gamma camera with the same condition applied to the simulation. Counts was decreased by 10% (air) and 54% (acrylic) with the parallel hole collimator and by 35% (air) and 63% (acrylic) with the diverging collimator. Spatial resolution was decreased as increasing the thickness of scatter media. This study substantiate the importance of a gamma camera positioning and the minimization of the distance between detector and target lesion in the clinical application of a gamma camera
Afanasyev, Leonid
2016-01-01
The Low Energy QCD allows to calculate the ππ and π K scattering lengths with high precision. There are accurate relations between these scattering lengths and π + π − , π − K + , π + K − atoms lifetimes. The experiment on the first observation of π − K + and π + K − atoms is described. The atoms were generated in Nickel and Platinum targets hit by the PS CERN proton beam with momentum of 24 GeV/ c . Moving in the target, part of atoms break up producing characteristic π K pairs (atomic pairs) with small relative momentum Q in their c.m.s. In the experiment, we detected n A = 349 ± 62 (5.6 standard deviations) π − K + and π + K − atomic pairs. The main part of π K pairs are produced in free state. The majority of such particles are generated directly or from short-lived sources as ρ , ω and similar resonances. The electromagnetic interactions in the final state create Coulomb pairs with a known sharp dependence on Q . This effect allows to evaluate the number of these Coulomb pai...
Radiative kaon capture on deuterium and the Λn scattering lengths
International Nuclear Information System (INIS)
Gall, K.P.; Booth, E.C.; Fickinger, W.J.; Hasinoff, M.D.; Hessey, N.P.; Horvath, D.; Lowe, J.; McIntyre, E.K.; Measday, D.F.; Miller, J.P.; Noble, A.J.; Roberts, B.L.; Robinson, D.K.; Sakitt, M.; Salomon, M.; Whitehouse, D.A.
1990-01-01
The photon spectrum from K - d→Λnγ at rest has been measured for the first time. We obtained the branching ratio, in the end-point region, of (1.89±0.12±0.28)x10 -3 where the first error is statistical and the second is systematic. We have found that the shape of the photon energy spectrum is consistent with the distribution calculated by Workman and Fearing with Λn scattering lengths and effective ranges predicted by the Nijmegen group
Determination of {pi}{pi} scattering lengths from measurement of {pi}{sup +{pi}-} atom lifetime
Energy Technology Data Exchange (ETDEWEB)
Adeva, B. [Santiago de Compostela University (Spain); Afanasyev, L. [JINR Dubna (Russian Federation); Benayoun, M. [LPNHE des Universites Paris VI/VII, IN2P3-CNRS (France); Benelli, A. [Zurich University (Switzerland); Berka, Z. [Czech Technical University in Prague, Prague (Czech Republic); Brekhovskikh, V. [IHEP Protvino (Russian Federation); Caragheorgheopol, G. [IFIN-HH, National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cechak, T. [Czech Technical University in Prague, Prague (Czech Republic); Chiba, M. [Tokyo Metropolitan University (Japan); Chliapnikov, P.V. [IHEP Protvino (Russian Federation); Ciocarlan, C.; Constantinescu, S. [IFIN-HH, National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Costantini, S. [Basel University (Switzerland); Curceanu, C. [IFIN-HH, National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Doskarova, P. [Czech Technical University in Prague, Prague (Czech Republic); Dreossi, D. [INFN, Sezione di Trieste and Trieste University, Trieste (Italy); Drijard, D., E-mail: Daniel.Drijard@cern.ch [CERN, Geneva (Switzerland); Dudarev, A. [JINR Dubna (Russian Federation); Ferro-Luzzi, M. [CERN, Geneva (Switzerland); Fungueirino Pazos, J.L. [Santiago de Compostela University (Spain)
2011-10-05
The DIRAC experiment at CERN has achieved a sizeable production of {pi}{sup +{pi}-} atoms and has significantly improved the precision on its lifetime determination. From a sample of 21 227 atomic pairs, a 4% measurement of the S-wave {pi}{pi} scattering length difference |a{sub 0}-a{sub 2}|=(0.2533{sub -0.0078}{sup +0.0080}|{sub stat}{sup +0.0078}{sub -0.0073}|{sub syst})M{sub {pi}}{sup +-1} has been attained, providing an important test of Chiral Perturbation Theory.
Scattering length measurements from radiative pion capture and neutron-deuteron breakup
International Nuclear Information System (INIS)
Gibson, B.F.; Tornow, W.; Carman, T.S.
1997-07-01
The neutron-neutron and neutron-proton 1 S 0 scattering lengths a nn and a np , respectively, were determined simultaneously from the neutron-deuteron breakup reaction. Their comparison with the recommended values obtained from two body reactions gives a measure of the importance of three-nucleon force effects in the three-nucleon continuum. In order to check on the result obtained for a nn from the two-body π - -d capture reaction, a new measurement was performed at LANL. Preliminary results of the three experiments are given
Electromagnetic effects and scattering lengths extraction from experimental data on K → 3π decays
International Nuclear Information System (INIS)
Gevorkyan, S.R.; Madigozhin, D.T.; Tarasov, A.V.; Voskresenskaya, O.O.
2008-01-01
The final state interactions in K ± → π ± π 0 π 0 decays are considered using the methods of non-relativistic quantum mechanics. We show how to take into account the largest electromagnetic effect in the analysis of experimental data using the amplitudes calculated earlier. We propose the relevant expressions for amplitude corrections valid both above and below the two charged pion production threshold M π 0 π 0 2m π ± , including the average effect for the threshold bin. These formulae can be used in the procedure of pion scattering lengths measurement from M π 0 π 0 spectrum
Experimental determination of anomalous scattering lengths of samarium for thermal neutrons
International Nuclear Information System (INIS)
Engel, D.W.; Koetzle, T.F.
1981-01-01
Anomalous scattering lengths of natural Sm for thermal neutrons with wavelengths between 0.827 and 1.300 A have been determined using a single crysrtal of a Sm-complex of known structure. 140 selected reflections were measured at each wavelength and b 0 + b' and b'' refined in each case. The values obtained are in good agreement with theoretical values obtained from a Breit-Wigner calculation using tabulated resonance parameters for 149 Sm. A value of b 0 = 4.3 +- 0.2 fm is deduced from the diffraction experiment
Laser scattering in large-scale-length plasmas relevant to National Ignition Facility hohlraums
International Nuclear Information System (INIS)
MacGowan, B.J.; Berger, R.L.; Afeyan, B.B.
1996-10-01
We have used homogeneous plasmas of high density (up to 1.3 X 10 21 electrons per cm 3 ) and temperature (∼ 3 keV) with large density scale lengths (∼2 mm) to approximate conditions within National Ignition Facility (NIF) hohlraums. Within these plasmas we have studied the dependence of stimulated Raman (SRS) and Brillouin (SBS) scattering on beam smoothing and plasma conditions at the relevant laser intensity (3ω, 2 X 10 15 Wcm 2 ). Both SBS and SRS are reduced by the use of smoothing by spectral dispersion (SSD)
Scattering length measurements from radiative pion capture and neutron-deuteron breakup
Energy Technology Data Exchange (ETDEWEB)
Tornow, W.; Chen, Q. [Duke Univ., Durham, NC (United States). Dept. of Physics; Carman, T.S. [Lawrence Livermore National Lab., CA (United States). Program for Climate Model Diagnosis and Intercomparison] [and others
1998-03-02
The neutron-neutron and neutron-proton {sup 1}S{sub 0} scattering lengths a{sub nn} and a{sub np}, respectively, were determined simultaneously from the neutron-deuteron breakup reaction. Their comparison with the recommended values obtained from ``two-body`` reactions gives a measure of the importance of three-nucleon force effects in the three-nucleon continuum. In order to check on the result obtained for a{sub nn} from the ``two-body`` {pi}{sup -}-d capture reaction, a new measurement was performed at LANL. Preliminary results of the three experiments are given. (orig.). 5 refs.
Biological Small Angle Scattering: Techniques, Strategies and Tips
Energy Technology Data Exchange (ETDEWEB)
Chaudhuri, Barnali [University at Buffalo (SUNY); Muñoz, Inés G. [Centro Nacional de Investigaciones Oncológicas Madrid, Madrid, Spain; Urban, Volker S. [ORNL; Qian, Shuo [ORNL
2017-12-01
This book provides a clear, comprehensible and up-to-date description of how Small Angle Scattering (SAS) can help structural biology researchers. SAS is an efficient technique that offers structural information on how biological macromolecules behave in solution. SAS provides distinct and complementary data for integrative structural biology approaches in combination with other widely used probes, such as X-ray crystallography, Nuclear magnetic resonance, Mass spectrometry and Cryo-electron Microscopy. The development of brilliant synchrotron small-angle X-ray scattering (SAXS) beam lines has increased the number of researchers interested in solution scattering. SAS is especially useful for studying conformational changes in proteins, highly flexible proteins, and intrinsically disordered proteins. Small-angle neutron scattering (SANS) with neutron contrast variation is ideally suited for studying multi-component assemblies as well as membrane proteins that are stabilized in surfactant micelles or vesicles. SAS is also used for studying dynamic processes of protein fibrillation in amyloid diseases, and pharmaceutical drug delivery. The combination with size-exclusion chromatography further increases the range of SAS applications.The book is written by leading experts in solution SAS methodologies. The principles and theoretical background of various SAS techniques are included, along with practical aspects that range from sample preparation to data presentation for publication. Topics covered include techniques for improving data quality and analysis, as well as different scientific applications of SAS. With abundant illustrations and practical tips, we hope the clear explanations of the principles and the reviews on the latest progresses will serve as a guide through all aspects of biological solution SAS.The scope of this book is particularly relevant for structural biology researchers who are new to SAS. Advanced users of the technique will find it helpful for
Iashina, E.G.; Bouwman, W.G.; Duif, C.P.; Filatov, M.V.; Grigoriev, S. V.
2017-01-01
Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrmeter length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei
Small angle scattering from protein/sugar conjugates
Energy Technology Data Exchange (ETDEWEB)
Jackson, Andrew [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)]. E-mail: ajj@nist.gov; White, John [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)
2006-11-15
The Maillard reaction between free amine groups on proteins and sugars is well known. We have examined the effect of the reaction of the casein group of milk proteins with sugars on their nanoscale structure and aggregation. The small angle neutron scattering from beta casein and sodium caseinate and their sugar conjugates have been studied as a function of solution concentration. At high conjugate concentration (greater than ca. 5mg/ml) the addition of sugar reduces supra-micellar aggregation of the protein whilst at lower concentration, where the protein is expected to be deaggregated already, little effect is seen. Guinier analysis of the scattering data show a radius of gyration of around 75A-bar for beta casein in solution and around 80A-bar for the sucrose conjugate.
Small angle scattering from protein/sugar conjugates
International Nuclear Information System (INIS)
Jackson, Andrew; White, John
2006-01-01
The Maillard reaction between free amine groups on proteins and sugars is well known. We have examined the effect of the reaction of the casein group of milk proteins with sugars on their nanoscale structure and aggregation. The small angle neutron scattering from beta casein and sodium caseinate and their sugar conjugates have been studied as a function of solution concentration. At high conjugate concentration (greater than ca. 5mg/ml) the addition of sugar reduces supra-micellar aggregation of the protein whilst at lower concentration, where the protein is expected to be deaggregated already, little effect is seen. Guinier analysis of the scattering data show a radius of gyration of around 75A-bar for beta casein in solution and around 80A-bar for the sucrose conjugate
Small angle scattering from protein/sugar conjugates
Jackson, Andrew; White, John
2006-11-01
The Maillard reaction between free amine groups on proteins and sugars is well known. We have examined the effect of the reaction of the casein group of milk proteins with sugars on their nanoscale structure and aggregation. The small angle neutron scattering from beta casein and sodium caseinate and their sugar conjugates have been studied as a function of solution concentration. At high conjugate concentration (greater than ca. 5 mg/ml) the addition of sugar reduces supra-micellar aggregation of the protein whilst at lower concentration, where the protein is expected to be deaggregated already, little effect is seen. Guinier analysis of the scattering data show a radius of gyration of around 75 A˚ for beta casein in solution and around 80 A˚ for the sucrose conjugate.
Consler, T G; Uberbacher, E C; Bunick, G J; Liebman, M N; Lee, J C
1988-02-25
The effects of ligands on the structure of rabbit muscle pyruvate kinase were studied by small angle neutron scattering. The radius of gyration, RG, decreases by about 1 A in the presence of the substrate phosphoenolpyruvate, but increases by about the same magnitude in the presence of the allosteric inhibitor phenylalanine. With increasing pH or in the absence of Mg2+ and K+, the RG of pyruvate kinase increases. Hence, there is a 2-A difference in RG between two alternative conformations. Length distribution analysis indicates that, under all experimental conditions which increase the radius of gyration, there is a pronounced increase observed in the probability for interatomic distance between 80 and 110 A. These small angle neutron scattering results indicate a "contraction" and "expansion" of the enzyme when it transforms between its active and inactive forms. Using the alpha-carbon coordinates of crystalline cat muscle pyruvate kinase, a length distribution profile was calculated, and it matches the scattering profile of the inactive form. These observations are expected since the crystals were grown in the absence of divalent cations (Stuart, D. I., Levine, M., Muirhead, H., and Stammers, D. K. (1979) J. Mol. Biol. 134, 109-142). Hence, results from neutron scattering, x-ray crystallographic, and sedimentation studies (Oberfelder, R. W., Lee, L. L.-Y., and Lee, J.C. (1984) Biochemistry 23, 3813-3821) are totally consistent with each other. With the aid of computer modeling, the crystal structure has been manipulated in order to effect changes that are consistent with the conformational change described by the solution scattering data. The structural manipulation involves the rotation of the B domain relative to the A domain, leading to the closure of the cleft between these domains. These manipulations resulted in the generation of new sets of atomic (C-alpha) coordinates, which were utilized in calculations, the result of which compared favorably with the
International Nuclear Information System (INIS)
Iton, L.E.; Brun, T.O.; Epperson, J.E.
1988-03-01
Small-angle neutron scattering is a useful new approach to the study of zeolite crystallization from aluminosilicate gels and the action of template molecules. It has been applied to gels for synthesis of zeolite ZSM-5 using tetrapropylammonium ions as templates where the scattering length densities of the gel particles and their texture were determined using contrast variation methods. Gels formulated from soluble silicate incorporate template molecules promptly into an amorphous ''embryonic'' structure and crystallization ensues via a solid hydrogel transformation mechanism. Gels formulated from colloidal silica show different scattering behavior, and a liquid phase transport mechanism is inferred. 8 refs., 4 figs., 2 tabs
Semi-inclusive deep inelastic scattering at small-x
International Nuclear Information System (INIS)
Marquet, Cyrille; Xiao, Bo-Wen; Yuan Feng
2009-01-01
We study the semi-inclusive hadron production in deep inelastic scattering at small-x. A transverse-momentum-dependent factorization is found consistent with the results calculated in the small-x approaches, such as the color-dipole framework and the color glass condensate, in the appropriate kinematic region at the lowest order. The transverse-momentum-dependent quark distribution can be studied in this process as a probe for the small-x saturation physics. Especially, the ratio of quark distributions as a function of transverse momentum at different x demonstrates strong dependence on the saturation scale. The Q 2 dependence of the same ratio is also studied by applying the Collins-Soper-Sterman resummation method.
Intrinsic pinning in superconductors with extremely small coherence lengths
International Nuclear Information System (INIS)
Schimmele, L.; Kronmueller, H.; Teichler, H.
1988-01-01
By means of a Ginsburg-Landau-type theory which takes into account the discrete lattice structure the variation of the energy ('Peierls potential') of an isolated flux line is calculated when shifted relatively to the crystal lattice. In particular, a primitive cubic lattice is considered with a straight flux line, aligned parallel to a cubic axis. The resulting Peierls potential may lead to intrinsic pinning if the coherence length is smaller than about two nearest neighbour distances. The coherence lengths at low temperatures determined for the recently discovered high T c superconductors of the YBa 2 Cu 3 O 7 class come very close to this value so that intrinsic pinning might possibly be relevant for these superconductors. (author)
International Nuclear Information System (INIS)
Albrecht, D.J.
1983-11-01
The aim of the present thesis was to study the defects in dielectrics produced by fast ions. For this the small angle scattering was proved as suitable method. By the production by means of the ion beam of an accelerator the defects possess a pronounced preferential direction. In scattering experiments this system of scattering centers is distinguished by its unusually strong dependence of the sample orientation according to the primary beam. This property was studied, described, and illustrated by examples, and it could by shown that from this additional informations about the scattering defects can be derived. For the first time nuclear tracks were detected by means of small angle neutron scattering. It could be shown that here the same results are obtained as by small angle X-ray scattering. The measured intensity distributions could be assigned to a mathematical model description which gives form, width, and density of the tracks in the position space. On the base of this cylinder model computer codes were established which simulate the scattering experiment regarding the main influences and calculate the expected theoretical intensity distribution. The agreement between calculated and measured scattering distributions proves the validity of the model. The parameters determined by this model, maximal change of density in the track, defect length, radial dilatation, distance of the narrowings and there depth were determined. For the main quantities, radial dilatation and maximal change of densities a simple description of the energy dependence could be given via the energy loss. (orig./HSI) [de
Scattering Manipulation and Camouflage of Electrically Small Objects through Metasurfaces
Vellucci, S.; Monti, A.; Toscano, A.; Bilotti, F.
2017-03-01
In this paper, we discuss the intriguing possibility of tailoring the scattering response of an electrically small object for camouflage and illusion applications using metasurfaces. As a significant example, we focus our attention on the cylindrical geometry and derive the analytical conditions needed to camouflage the geometrical and electrical characteristics of dielectric and metallic cylinders coated with ideal metasurfaces. A closed-form expression of the camouflaging metasurface depending on the cylinder's characteristics is derived. Furthermore, the frequency behavior and the limitations of this technique are discussed with the aid of relevant examples. In order to overcome these limitations, a solution based on the use of lossy metasurfaces is proposed.
Influence of core diameter and length of polymer optical fiber on Brillouin scattering properties
Mizuno, Yosuke; Ishigure, Takaaki; Nakamura, Kentaro
2012-02-01
Brillouin scattering in perfluorinated graded-index polymer optical fibers (PFGI-POFs) is potentially useful in developing high-accuracy distributed temperature sensors with reduced strain sensitivity. In this study, we investigate, both experimentally and theoretically, the influence of the fiber core diameter and length on the Brillouin gain spectra (BGS) in PFGI-POFs. First, we show that smaller core diameter drastically enhances the Stokes power using PFGI-POFs with 62.5-μm and 120-μm core diameters, and discuss the Brillouin threshold power. Then, we demonstrate that the PFGI-POF length has little influence on the BGS when the length is longer than 50 m. We also predict that, at 1.55-μm wavelength, it is difficult to reduce the Brillouin threshold power of PFGI-POFs below that of long silica single-mode fibers even if their core diameter is sufficiently reduced to satisfy the single-mode condition. Finally, making use of the enhanced Stokes signal, we confirm the Brillouin linewidth narrowing effect.
Soliton scatterings by impurities in a short-length sine-Gordon chain
International Nuclear Information System (INIS)
Dikande, A.M.; Kofane, T.C.
1995-07-01
The scattering of soliton by impurities at the frontiers of a finite-length region of an infinite sine-Gordon chain is analyzed. The impurities consist of two isotopic inhomogeneities installed at the boundaries of the finite-length region. The soliton solution in the region is found in term of snoidal sine-Gordon soliton which properly takes into account the effects of the boundaries. By contrast, the soliton solutions in the neighboring sides of the region are obtained in terms of the so-called large-amplitude, localized kinks with limiting spatial extensions at x → ± ∞, which is equal ±π. Using the continuity of these soliton solutions at the frontiers as well as appropriate boundary conditions, it is shown that the soliton may be either i) reflected by the incident impurity; ii) trapped (with oscillating motions) between the two impurities (i.e. inside the infinite region); or iii) transmitted by the second impurity into the third, infinitely extended region. The threshold velocities for the reflection and transmission into different regions are found and shown to vary exponentially as a function of the length of the bounded region. The frequency of soliton oscillations between the impurities has also been calculated in some acceptable limit. (author). 28 refs, 1 fig
The University of New Mexico/Sandia National Laboratories small-angle scattering laboratory
International Nuclear Information System (INIS)
Rieker, T.P.; Hubbard, P.F.
1998-01-01
The University of New Mexico/Sandia National Laboratories small-angle scattering laboratory provides a wide q-range, 3x10 -4 Angstrom -1 -1 , for the structural analysis of materials on length scales from a few angstrom to ∼0.1 μm. The wide q-range is accomplished by combining data from a Bonse-Hart spectrometer (3x10 -4 Angstrom -1 -2 Angstrom -1 ) and a 5 m pinhole (3x10 -3 Angstrom -1 -1 ) instrument. Automation of the data acquisition systems along with a variety of sample environments and sample changers yields flexible, high throughput instruments. copyright 1998 American Institute of Physics
Small-angle neutron scattering from multilamellar lipid bilayers: Theory, model, and experiment
DEFF Research Database (Denmark)
Lemmich, Jesper; Mortensen, Kell; Ipsen, John Hjorth
1996-01-01
Small-angle neutron scattering data obtained from fully hydrated, multilamellar phospholipid bilayers with deuterated acyl chains of different length are presented and analyzed within a paracrystalline theory and a geometric model that permit the bilayer structure to be determined under conditions...... of temperature for the lamellar repeat distance, the hydrophobic bilayer thickness, as well as the thickness of the aqueous and polar head group region. In addition to these geometric parameters the analysis permits determination of molecular cross-sectional area, number of interlamellar water molecules, as well...
Time-of-flight small-angle scattering spectrometers on pulsed neutron sources
International Nuclear Information System (INIS)
Ostanevich, Yu.M.
1987-01-01
The operation principles, constructions, advantages and shortcomings of known time-of-flight small angle neutron scattering (TOF SANS) spectrometers built up with pulsed neutron sources are reviewed. The most important characteristics of TOF SANS apparatuses are rather a high luminosity and the possibility for the measurement in an extremely wide range of scattering vector at a single exposure. This is achieved by simultaneous employment of white beam, TOF technique for wave length-scan and the commonly known angle-scan. However, the electronic equipment, data-matching programs, and the measurement procedure, necessary for accurate normalization of experimental data and their transformation into absolute cross-section scale, they all become more complex, as compared with those for SANS apparatuses operating on steady-state neutron sources, where only angle-scan is used
Recent high-accuracy measurements of the 1S0 neutron-neutron scattering length
International Nuclear Information System (INIS)
Howell, C.R.; Chen, Q.; Gonzalez Trotter, D.E.; Salinas, F.; Crowell, A.S.; Roper, C.D.; Tornow, W.; Walter, R.L.; Carman, T.S.; Hussein, A.; Gibbs, W.R.; Gibson, B.F.; Morris, C.; Obst, A.; Sterbenz, S.; Whitton, M.; Mertens, G.; Moore, C.F.; Whiteley, C.R.; Pasyuk, E.; Slaus, I.; Tang, H.; Zhou, Z.; Gloeckle, W.; Witala, H.
2000-01-01
This paper reports two recent high-accuracy determinations of the 1 S 0 neutron-neutron scattering length, a nn . One was done at the Los Alamos National Laboratory using the π - d capture reaction to produce two neutrons with low relative momentum. The neutron-deuteron (nd) breakup reaction was used in other measurement, which was conducted at the Triangle Universities Nuclear Laboratory. The results from the two determinations were consistent with each other and with previous values obtained using the π - d capture reaction. The value obtained from the nd breakup measurements is a nn = -18.7 ± 0.1 (statistical) ± 0.6 (systematic) fm, and the value from the π - d capture experiment is a nn = -18.50 ± 0.05 ± 0.53 fm. The recommended value is a nn = -18.5 ± 0.3 fm. (author)
Meson-Baryon Scattering Lengths from Mixed-Action Lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Will Detmold, William Detmold, Konstantinos Orginos, Aaron Torok, Silas R Beane, Thomas C Luu, Assumpta Parreno, Martin Savage, Andre Walker-Loud
2010-04-01
The $\\pi^+\\Sigma^+$, $\\pi^+\\Xi^0$ , $K^+p$, $K^+n$, and $K^0 \\Xi^0$ scattering lengths are calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks is used to perform the chiral extrapolations. We find no convergence for the kaon-baryon processes in the three-flavor chiral expansion. Using the two-flavor chiral expansion, we find $a_{\\pi^+\\Sigma^+} = ?0.197 ± 0.017$ fm, and $a_{\\pi^+\\Xi^0} = ?0.098 0.017$ fm, where the comprehensive error includes statistical and systematic uncertainties.
An upgrade beamline for combined wide, small and ultra small-angle x-ray scattering at the ESRF
Energy Technology Data Exchange (ETDEWEB)
Van Vaerenbergh, Pierre; Léonardon, Joachim; Sztucki, Michael; Boesecke, Peter; Gorini, Jacques; Claustre, Laurent; Sever, Franc; Morse, John; Narayanan, Theyencheri [ESRF - The European Synchrotron, F-38043 Grenoble (France)
2016-07-27
This contribution presents the main design features of the upgraded beamline ID02 (TRUSAXS). The beamline combines different small-angle X-ray scattering techniques in one unique instrument. The key component of this instrument is an evacuated (5×10{sup −3} mbar) stainless steel detector tube of length 34 m and diameter 2 m. Three different detectors (Rayonix MX170, Pilatus 300 K and FReLoN 4M) are housed inside a motorized wagon which travels along a rail system with very low parasitic lateral movements (± 0.3 mm). This system allows automatically changing the sample-to-detector distance from about 1 m to 31 m and selecting the desired detector. In addition, a wide angle detector (Rayonix LX170) is installed just above the entrance cone of the tube for optional wide-angle X-ray scattering measurements. The beamstop system enables monitoring of the X-ray beam intensity in addition to blocking the primary beam, and automated insertion of selected masks behind the primary beamstop. The focusing optics and collimation system permit to cover a scattering vector (q) range of 0.002 nm{sup −1} ≤ q ≤ 50 nm{sup −1} with one unique setting using 0.1 nm X-ray wavelength for moderate flux (5×10{sup 12} photons/sec). However, for higher flux (6x10{sup 13} photons/sec) or higher resolution (minimum q < 0.001 nm{sup −1}), focusing and collimation, respectively need to be varied. For a sample-to-detector distance of 31 m and 0.1 nm wavelength, two dimensional ultra small-angle X-ray scattering patterns can be recorded down to q≈0.001 nm{sup −1} with far superior quality as compared to one dimensional profiles obtained with a Bonse-Hart instrument.
Koizumi, S; Richter, D; Schwahn, D; Faragó, B; Annaka, M
2002-01-01
By employing neutron spin echo and small-angle neutron scattering, we determined the structure factor of the frozen concentration fluctuations on nano-length scales in a swollen poly(N-isopropyl acrylamide) gel. The frozen contribution, showing a plateau at the low scattering wavenumber q (0.02 A sup - sup 1), is intimately related to the abnormal butterfly scattering pattern appearing at low q under deformation. (orig.)
Extraction of the missing low-Q data from small-angle scattering data
International Nuclear Information System (INIS)
Doherty, G.K.; Poland, G.A.
1996-01-01
A new method is presented that recovers the scatter intensity curve at low Q values from small-angle neutron scattering data. The method uses only the measured data, requiring no extrapolation of the scatter curve nor any a priori knowledge of the maximum chord length, radius of gyration or molecular weight of the particle under investigation. It is assumed that the incoherent level would have been extracted from the data in the normal course of events but any errors do not affect the method presented. The distance distribution function of any particle has a restricted extension in real space and any nonzero value beyond the maximum size of the particle is due to the effects of missing data segments and noise on the measured data. The effects due to the missing and noisy data are isolated from the distance distribution of the particle and a suitably scaled template particle is used to fill in the missing distribution data segment. The inverse transform of the new distribution function returns the missing low-Q scatter data and to some extent cancels out the noise. While the method is generally explored using noise-free analytically derived particles, its application to real experimental data is demonstrated. (orig.)
Joint small-angle X-ray and neutron scattering data analysis of asymmetric lipid vesicles
International Nuclear Information System (INIS)
Eicher, Barbara; Heberle, Frederick A.; Marquardt, Drew T.
2017-01-01
Low- and high-resolution models describing the internal transbilayer structure of asymmetric lipid vesicles have been developed. These models can be used for the joint analysis of small-angle neutron and X-ray scattering data. The models describe the underlying scattering length density/electron density profiles either in terms of slabs or through the so-called scattering density profile, previously applied to symmetric lipid vesicles. Both models yield structural details of asymmetric membranes, such as the individual area per lipid, and the hydrocarbon thickness of the inner and outer bilayer leaflets. The scattering density profile model, however, comes at a cost of increased computational effort but results in greater structural resolution, showing a slightly lower packing of lipids in the outer bilayer leaflet of ~120 nm diameter palmitoyloleoyl phosphatidylcholine (POPC) vesicles, compared to the inner leaflet. Here, analysis of asymmetric dipalmitoyl phosphatidylcholine/POPC vesicles did not reveal evidence of transbilayer coupling between the inner and outer leaflets at 323 K,i.e.above the melting transition temperature of the two lipids.
Study of α-crystallin structure by small-angle neutron scattering with contrast variation
International Nuclear Information System (INIS)
Krivandin, A.V.; Muranov, K.O.; Polyanskij, N.B.; Ostrovskij, M.A.; Murugova, T.N.; Kuklin, A.I.; Aksenov, V.L.
2010-01-01
The structure of the oligomeric protein α-crystallin from the bovine eye lens has been investigated by small-angle neutron scattering (SANS) by the contrast variation method (volume fraction of D 2 O was 0, 23, 68 and 90%). Experiments were carried out on YuMO spectrometer (IBR-2 reactor, JINR). From the SANS curves the match point for α-crystallin (43% D 2 O) and its average scattering length density at this point (2.4·10 10 cm -2 ) have been obtained. The radius of gyration and distance distribution functions for α-crystallin have been calculated as well. On the basis of these calculations it was concluded that α-crystallin has a homogeneous distribution of the scattering density in domains inaccessible for water penetration and all parts of this protein undergo a uniform deuteration. The latter indicates that all α-crystallin subunits have an equal accessibility for water and presumably for some other low molecular weight substances. These conclusions on the α-crystallin structure (a homogeneous distribution of the scattering density and an equal accessibility of all subunits for low molecular weight substances) should be taken into account in the time of elaboration of α-crystallin quaternary structure models
Particle-scale structure in frozen colloidal suspensions from small-angle x-ray scattering
Spannuth, Melissa; Mochrie, S. G. J.; Peppin, S. S. L.; Wettlaufer, J. S.
2011-01-01
During directional solidification of the solvent in a colloidal suspension, the colloidal particles segregate from the growing solid, forming high-particle-density regions with structure on a hierarchy of length scales ranging from that of the particle-scale packing to the large-scale spacing between these regions. Previous work has concentrated mostly on the medium- to large-length scale structure, as it is the most accessible and thought to be more technologically relevant. However, the packing of the colloids at the particle scale is an important component not only in theoretical descriptions of the segregation process, but also to the utility of freeze-cast materials for new applications. Here we present the results of experiments in which we investigated this structure across a wide range of length scales using a combination of small-angle x-ray scattering and direct optical imaging. As expected, during freezing the particles were concentrated into regions between ice dendrites forming a microscopic pattern of high- and low-particle-density regions. X-ray scattering indicates that the particles in the high-density regions were so closely packed as to be touching. However, the arrangement of the particles does not conform to that predicted by standard interparticle pair potentials, suggesting that the particle packing induced by freezing differs from that formed during equilibrium densification processes. © 2011 American Physical Society.
Particle-scale structure in frozen colloidal suspensions from small-angle x-ray scattering
Spannuth, Melissa
2011-02-01
During directional solidification of the solvent in a colloidal suspension, the colloidal particles segregate from the growing solid, forming high-particle-density regions with structure on a hierarchy of length scales ranging from that of the particle-scale packing to the large-scale spacing between these regions. Previous work has concentrated mostly on the medium- to large-length scale structure, as it is the most accessible and thought to be more technologically relevant. However, the packing of the colloids at the particle scale is an important component not only in theoretical descriptions of the segregation process, but also to the utility of freeze-cast materials for new applications. Here we present the results of experiments in which we investigated this structure across a wide range of length scales using a combination of small-angle x-ray scattering and direct optical imaging. As expected, during freezing the particles were concentrated into regions between ice dendrites forming a microscopic pattern of high- and low-particle-density regions. X-ray scattering indicates that the particles in the high-density regions were so closely packed as to be touching. However, the arrangement of the particles does not conform to that predicted by standard interparticle pair potentials, suggesting that the particle packing induced by freezing differs from that formed during equilibrium densification processes. © 2011 American Physical Society.
Magnetic particles studied with neutron depolarization and small-angle neutron scattering
International Nuclear Information System (INIS)
Rosman, R.
1991-01-01
Materials containing magnetic single-domain particles, referred to as 'particulate media', have been studied using neutron depolarization (ND) and small-angle neutron scattering (SANS). In a ND experiment the polarization vector of a polarized neutron beam is analyzed after transmission through a magnetic medium. Such an analysis in general yields the correlation length of variations in magnetic induction along the neutron path (denoted 'magnetic correlation length'), mean orientation of these variations and mean magnetic induction. In a SANS experiment, information about nuclear and magnetic inhomogeneities in the medium is derived from the broadening of a generally unpolarized neutron beam due to scattering by these inhomogeneities. Spatial and magnetic microstructure of a variety of particulate media have been studied using ND and/or SANS, by determination of the magnetic or nuclear correlation length in these media in various magnetic states. This thesis deals with the ND theory and its application to particulate media. ND and SANS experiments on a variety of particulate media are discussed. (author). 178 refs., 97 figs., 8 tabs
International Nuclear Information System (INIS)
Takenaka, Mikihito; Nishitsuji, Shotaro; Yamaguchi, Daisuke; Koizumi, Satoshi
2009-01-01
Full text: The polymer layers absorbed on silica particles in rubber-silica systems have investigated with contrast variation small-angle neutron scattering (SANS) method. The scattering intensities of specimens swollen by the solvents having various scattering length densities were measured. The contrast variation SANS for the specimens yielded partial scattering functions: the scattering function for polymer-polymer correlation SPP(q), the scattering function for silica- silica correlation SSS(q), and the scattering function for polymer- silica correlation SPS(q). The analyses of SSS(q) explored the hierarchical structures formed by silica particles. The analyses of SPS(q) and SSS(q) clarified the existence of dense polymer layers around silica aggregates. Several characteristic parameters are estimated from the analyses, such as the size of aggregates, the thickness of layers, the volume fractions of polymer of layers and matrix, and the correlation length of the matrix network. The contrast variation SANS is found to be a powerful tool of the analyses of the structures of the rubber-filler systems. (author)
An analytical approach to estimate the number of small scatterers in 2D inverse scattering problems
International Nuclear Information System (INIS)
Fazli, Roohallah; Nakhkash, Mansor
2012-01-01
This paper presents an analytical method to estimate the location and number of actual small targets in 2D inverse scattering problems. This method is motivated from the exact maximum likelihood estimation of signal parameters in white Gaussian noise for the linear data model. In the first stage, the method uses the MUSIC algorithm to acquire all possible target locations and in the next stage, it employs an analytical formula that works as a spatial filter to determine which target locations are associated to the actual ones. The ability of the method is examined for both the Born and multiple scattering cases and for the cases of well-resolved and non-resolved targets. Many numerical simulations using both the coincident and non-coincident arrays demonstrate that the proposed method can detect the number of actual targets even in the case of very noisy data and when the targets are closely located. Using the experimental microwave data sets, we further show that this method is successful in specifying the number of small inclusions. (paper)
Electrons scattered inside small dust grains of various materials
International Nuclear Information System (INIS)
Richterova, Ivana; Beranek, Martin; Pavlu, Jiri; Nemecek, Zdenek; Safrankova, Jana
2010-01-01
The dust grain charge in an electron beam is given by a difference in numbers of electrons that fall onto the grain and those leaving it. Electrons with energies exceeding 1 keV can penetrate through submicron-sized dust grains. If the grain is small enough, a yield of these electrons reaches unity but they leave a part of their energy inside the grain and this energy excites secondary electrons. The paper presents a hybrid Monte Carlo code that simulates paths of the primary electrons inside a spherical grain and provides the yield of scattered electrons and their energy spectrum as a function of the grain size and material. This code is based on the Richterovaet al. [Phys. Rev. B 74, 235430 (2006)] model but it includes several corrections important for light materials like carbon or ice. The model was verified using experimental results obtained on large planar samples. For spherical samples, we have found that the yield of scattered electrons reaches unity for 50 nm Au grains illuminated by 5 keV electrons, whereas the same effect can be observed on ≅1000 nm carbon grains.
Sensing small changes in a wave chaotic scattering system
International Nuclear Information System (INIS)
Taddese, Biniyam Tesfaye; Antonsen, Thomas M.; Ott, Edward; Anlage, Steven M.
2010-01-01
Classical analogs of the quantum mechanical concepts of the Loschmidt Echo and quantum fidelity are developed with the goal of detecting small perturbations in a closed wave chaotic region. Sensing techniques that employ a one-recording-channel time-reversal-mirror, which in turn relies on time reversal invariance and spatial reciprocity of the classical wave equation, are introduced. In analogy with quantum fidelity, we employ scattering fidelity techniques which work by comparing response signals of the scattering region, by means of cross correlation and mutual information of signals. The performance of the sensing techniques is compared for various perturbations induced experimentally in an acoustic resonant cavity. The acoustic signals are parametrically processed to mitigate the effect of dissipation and to vary the spatial diversity of the sensing schemes. In addition to static boundary condition perturbations at specified locations, perturbations to the medium of wave propagation are shown to be detectable, opening up various real world sensing applications in which a false negative cannot be tolerated.
Energy Technology Data Exchange (ETDEWEB)
Couturier, Laurent, E-mail: laurent.couturier55@hotmail.fr [Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble (France); CNRS, SIMAP, F-38000 Grenoble (France); Department of Materials Engineering, The University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); De Geuser, Frédéric; Deschamps, Alexis [Univ. Grenoble Alpes, SIMAP, F-38000 Grenoble (France); CNRS, SIMAP, F-38000 Grenoble (France)
2016-11-15
The fine microstructure obtained by unmixing of a solid solution either by classical precipitation or spinodal decomposition is often characterized either by small angle scattering or atom probe tomography. This article shows that a common data analysis framework can be used to analyze data obtained from these two techniques. An example of the application of this common analysis is given for characterization of the unmixing of the Fe-Cr matrix of a 15-5 PH stainless steel during long-term ageing at 350 °C and 400 °C. A direct comparison of the Cr composition fluctuations amplitudes and characteristic lengths obtained with both techniques is made showing a quantitative agreement for the fluctuation amplitudes. The origin of the discrepancy remaining for the characteristic lengths is discussed. - Highlights: •Common analysis framework for atom probe tomography and small angle scattering •Comparison of same microstructural characteristics obtained using both techniques •Good correlation of Cr composition fluctuations amplitudes from both techniques •Good correlation of Cr composition fluctuations amplitudes with classic V parameter.
User's guide for the small-angle neutron scattering facility
International Nuclear Information System (INIS)
Vlak, W.A.H.M.; Werkhoven, E.J.
1989-04-01
This report serves as a manual for the users of the small-angle neutron scattering instrument located at beamport HB3 of the High Flux Reactor in Petten. The main part of the text is devoted to the control of the facility and the data handling by means of a μVAX computer. Also, the various possibilities to access the facility across computer networks are discussed. A collection of menu-driven and command-driven programs, which utilize the flexibility of the VMS operating system without requiring detailed knowledge of the user about the computer environment, enables to control the instrument. For the convenience of the experienced user, who might wish to update or extend the software, a technical supplement is included. 15 figs.; 8 refs
A small angle neutron scattering study of thermoplastic elastomer
Energy Technology Data Exchange (ETDEWEB)
Sutiarso,; Edy Giri, R Putra; Andon, Insani; Sudirman,; Sudaryanto, [Materials Science Research Centre, National Atomic Energy Agency, Jakarta (Indonesia)
1998-10-01
A bilateral scientific cooperation, in the small angle neutron scattering has been agreed upon between CIAE, China and BATAN, Indonesia as well as MINT Malaysia. As stated in the agreed proposal that the objective of this cooperation, in the initial stage (stage-1), was to have a regional intercomparison measurements of SANS instruments in order to determine their characteristic/performance. Therefore, this report is supposed to describe the progress in the SANS instrument development of each country involved during the period of 1996/97 and some activities related to the SANS instrument. Since, up to now, we have not yet received any progresses reported from either China or Malaysia, this report will describe the progress of SANS`s activities in BATAN only. (author)
Small angle X-ray scattering on concentrated hemoglobin solutions
International Nuclear Information System (INIS)
Zinke, M.; Damaschun, G.; Mueller, J.J.; Ruckpaul, K.
1978-01-01
The small-angle X-ray scattering technique was used to determine the intermolecular structure and interaction potentials in oxi-and deoxi-hemoglobin solutions. The pair correlation function obtained by the ZERNICKE-PRINS equation characterizes the intermolecular structure of the hemoglobin molecules. The intermolecular structure is concentration dependent. The hemoglobin molecules have a 'short range order structure' with a range of about 4 molecule diameters at 324 g/l. The potential functions of the hemoglobin-hemoglobin interaction have been determined on the basis of fluid theories. Except for the deoxi-hemoglobin solution having the concentration 370 g/l, the pair interaction consists in a short repulsion and a weak short-range attraction against kT. The potential minimum is between 1.2 - 1.5 nm above the greatest hemoglobin diameter. (author)
The small angle neutron scattering study on the segmented polyurethane
International Nuclear Information System (INIS)
Sudirman; Gunawan; Prasetyo, S.M.; Karo Karo, A.; Lahagu, I.M.; Darwinto, Tri
1999-01-01
The distance between hard segment (HS) and soft segment (SS) of segmented polyurethane have been determined using the Small Angle Neutron Scattering (SANS) technique. The segmented Polyurethanes (SPU) are linear multiblock copolymers, which include elastomer thermoplastic. SPU consist of hard segment and soft segment, each has tendency to make a group with similar type to form a domain. The soft segments used were polypropylene glycol (PPG) and 4,4 diphenylmethane diisocyanate (MDI), while l,4 butanediol (BD) was used as hard segment. The characteristic of SPU depends on its phase structure which is affected by several factors, such as type of chemical formula and the composition of the HS and SS, solvent as well as the synthesizing process. The samples used in this study were SPU56 and SPU68. Based on the appearance of SANS profile, it was obtained that domain distances are 12.32 nm for the SPU56 and 19 nm for the SPU68. (author)
Scanning small angle X-ray scattering investigations of bone
International Nuclear Information System (INIS)
Rinnerthaler, S.
1998-06-01
An important characteristic of bone is its strength, which is determined by bone mass, architecture and material quality. From a physical point of view bone is a composite material consisting of an organic matrix (collagen) and of inlets of mineral crystals (hydroxyapatite). These components build up a hierarchical, heterogeneous structure. The size of the mineral crystals lies in the nano-meter range and can be investigated by positionsensitive Small-Angle X-ray Scattering (Scanning-SAXS) in a non-destructive way. The average thickness, the degree and direction of the predominant orientation, as well as some information about shape and arrangement of the mineral crystals were determined in bones of humans, mice, and baboons by Scanning-SAXS with respect to age, bone diseases (osteogenesis imperfecta, pycnodysostosis) or medical treatments (fluoride or alendronate) of osteoporosis. The crystal thickness and the degree of orientation is much smaller in young individuals than in adults and the predominant orientation of the mineral crystals is different in a mixture of bone and mineralized cartilage compared to bone. Further, because position-resolved measurements are now possible, results from Scanning-SAXS measurements could be compared with the results of other position resolved methods. Due to this new feature it was possible, for the first time, to correlate directly 'mottled' bone visible in back-scattered electron imaging with small η-parameters evaluated from SAXS-patterns and the course of the collagen fibers with the predominant orientation of the mineral crystals. Scanning-SAXS proved to be a powerful tool to characterize bone nano-structure. (author)
The pion-nucleon scattering lengths from pionic hydrogen and deuterium
Energy Technology Data Exchange (ETDEWEB)
Schroeder, H.-C.; Badertscher, A.; Goudsmit, P.F.A.; Janousch, M.; Leisi, H.J.; Matsinos, E.; Sigg, D.; Zhao, Z.G. [ETH Zurich, Inst. for Particle Physics, Zurich (Switzerland); Chatellard, D.; Egger, J.P. [Neuchatel Univ. (Switzerland). Inst. de Physique; Gabathuler, K.; Hauser, P.; Simons, L.M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Rusi El Hassani, A.J. [Dept. de Physique, Faculte des Sciences et Technique, Tanger (Morocco)
2001-07-01
This is the final publication of the ETH Zurich-Neuchatel-PSI collaboration on the pionic hydrogen and deuterium precision X-ray experiments. We describe the recent hydrogen 3p-1s measurement, report on the determination of the Doppler effect correction to the transition line width, analyze the deuterium shift measurement and discuss implications of the combined hydrogen and deuterium results. From the pionic hydrogen 3p-1s transition experiments we obtain the strong-interaction energy level shift {epsilon}{sub 1s} = -7.108{+-}0.013 (stat.){+-}0.034 (syst.) eV and the total decay width {gamma}{sub 1s} = 0.868{+-}0.040 (stat.){+-}0.038 (syst.) eV of the 1s state. Taking into account the electromagnetic corrections we find the hadronic {pi}N s-wave scattering amplitude a{sub {pi}{sup -}p{yields}{pi}{sup -}p} = 0.0883{+-}0.0008 m{sub {pi}}{sup -1} for elastic scattering and a{sub {pi}{sup -}p{yields}{pi}{sup 0}n} = -0.128{+-}0.006 m{sub {pi}} {sup -1} for single charge exchange, respectively. We then combine the pionic hydrogen results with the 1s level shift measurement on pionic deuterium and test isospin symmetry of the strong interaction: our data are still compatible with isospin symmetry. The isoscalar and isovector {pi}N scattering lengths (within the framework of isospin symmetry) are found to be b{sub 0} = -0.0001{sup +0.0009}{sub -0.0021} m{sub {pi}}{sup -1} and b{sub 1} = -0.0885{sup +0.0010}{sub -0.0021} m{sub {pi}} {sup -1}, respectively. Using the GMO sum rule, we obtain from b{sub 1} a new value of the {pi}N coupling constant (g{sub {pi}}{sub N} = 13.21{sub -0.05}{sup +0.11}) from which follows the Goldberger-Treiman discrepancy {delta}{sub GT}=0.027{sub -0.008}{sup +0.012}. The new values of b{sub 0} and g{sub {pi}}{sub N} imply an increase of the nucleon sigma term by at least 9 MeV. (orig.)
International Nuclear Information System (INIS)
Correa, J.R.; Chang Yongbin; Ordonez, C.A.
2005-01-01
Collisional scattering is considered within a system of charged particles experiencing binary Coulomb interactions when the scale length for the range of each interaction is not isotropic and is not necessarily equal to the Debye length. For example, one or more dimensions of the system could be smaller than the Debye length. The effect is assessed by evaluating integrals over the impact cross section. Cutoffs on both the impact parameter and the Coulomb interaction potential are employed, and no assumption is made regarding the value of the Coulomb logarithm. Two expressions are found that have a dependence on the cutoff lengths, with one of the expressions being associated with the Coulomb logarithm. Collisional scattering within an electrostatic ion trap is considered by way of example
Intracluster superelastic scattering via sequential photodissociation in small HI clusters
International Nuclear Information System (INIS)
Chastaing, D.; Underwood, J.; Wittig, C.
2003-01-01
The photodissociation of expansion-cooled HI monomer by using 266 nm radiation yields H atoms having 12 830 and 5287 cm-1 of translational energy in the HI center-of-mass system for the I( 2 P 3/2 ) and I( 2 P 1/2 ) (i.e., I and I * , respectively) co-fragments. Irradiating HI clusters [i.e., (HI) n , with n=2 being the dominant cluster] with 266 nm radiation produces, among other things, some H atoms whose translational energies are peaked at 20 285 cm-1, which is 7455 cm-1 higher in energy than the more energetic of the monomer peaks. These very fast H atoms arise from sequential photodissociation within the clusters. Namely, a weakly bound I*·(HI) n-1 complex is first created by the photodissociation of an HI moiety within (HI) n , and then the photodissociation of a second HI moiety [within I*·(HI) n-1 ] produces a fast H atom that scatters from the nearby I*, in some cases deactivating it in the process. Thus, the latter superelastically scattered H atom acquires, as translational energy, nearly all of the I* energy (7603 cm-1). For example, for the dimer, the first dissociation event, (HI) 2 +hv→H+I(I*)·HI, is followed by I*·HI+hv→H superelastic +I-I. High quality potentials for the relevant HI excited states have been calculated recently, and coupling between 3 Π 0 + (which correlates with I * ) and 1 Π (which correlates with I) has been shown to be due to spin-rotation interaction. There is a high degree of separability between the photodissociation of the second HI moiety and the subsequent H+I * scattering (within a given cluster). This is due mainly to the shape of the 3 Π 0 + potential; specifically, it has a shallow well that persists to small r. The shape of the 3 Π 0 + potential is influenced by relativity; i.e., strong spin-orbit coupling maintains the I* spherical electron density to relatively small r. The 3 Π 0 + → 1 Π transition probabilities are calculated for H+I * collisions having different values of the collisional orbital
Extraction of neutron-neutron scattering length from nn coincidence-geometry nd breakup data
Directory of Open Access Journals (Sweden)
E. S. Konobeevski
2011-03-01
Full Text Available We report preliminary results of a kinematically complete experiment on measurement of nd breakup reaction yield at neutron beam RADEX of Institute for Nuclear Research (Moscow, Russia. In the experiment two secondary neutrons are detected in geometry of neutron-neutron final-state interaction. Data are obtained at energy of incident neutrons En = 40 - 60 MeV for various divergence angles of two neutrons ΔΘ = 4, 6, 8º. 1S0 neutron-neutron scattering length ann were determined by comparison of the experimental dependence of reaction yield on the relative energy of two secondary neutrons with results of simulation depending on ann. For En = 40 MeV and ΔΘ = 6º (the highest statistics in the experiment the value ann = -17.9 ± 1.0 fm is obtained. The further improving of accuracy of the experiment and more rigorous theoretical analysis will allow one to remove the existing difference in ann values obtained in different experiments.
Meson-Baryon Scattering Lengths from Mixed-Action Lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Beane, S; Detmold, W; Luu, T; Orginos, K; Parreno, A; Torok, A; Walker-Loud, A
2009-06-30
The {pi}{sup +}{Sigma}{sup +}, {pi}{sup +}{Xi}{sup 0}, K{sup +}p, K{sup +}n, {bar K}{sup 0}{Sigma}{sup +}, and {bar K}{sup 0}{Xi}{sup 0} scattering lengths are calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks is used to perform the chiral extrapolations. We find no convergence for the kaon-baryon processes in the three-flavor chiral expansion. Using the two-flavor chiral expansion, we find a{sub {pi}{sup +}{Sigma}{sup +}} = -0.197 {+-} 0.017 fm, and a{sub {pi}{sup +}{Xi}{sup 0}} = -0.098 {+-} 0.017 fm, where the comprehensive error includes statistical and systematic uncertainties.
International Nuclear Information System (INIS)
Kuzmanovic, Deborah A.; Elashvili, Ilya; O'Connell, Catherine; Krueger, Susan
2008-01-01
Small-angle scattering (SAS) techniques, like small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS), were used to measure and thus to validate the accuracy of a novel technology for virus sizing and concentration determination. These studies demonstrate the utility of SAS techniques for use in quality assurance measurements and as novel technology for the physical characterization of viruses
Detection of small conformational changes of proteins by small-angle scattering
International Nuclear Information System (INIS)
Durchschlag, H.; Purr, G.; Zipper, P.; Wilfing, R.
1991-01-01
In the past the technique of small-angle scattering has been a powerful tool for studying conformational changes of protein which occur, for example, upon binding with ligands. Results obtained by different authors from X-ray and neutron experiments on a variety of proteins and under various conditions have been compiled. This offers the possibility of comparing the extent of changes in the molecular parameters investigated (e.g. change of the radius of gyration). Problems encountered with the detection of small changes are discussed. As an example, conformational changes of the enzyme citrate synthase upon substrate binding (oxaloacetate) are presented. X-ray crystallography had already found distinct changes between open and closed forms of the enzyme. Small-angle X-ray scattering studies registered slight changes of some parameters in solution. These changes could be paralleled with the results of other solution techniques (UV absorption, fluorescence and circular dichroism spectroscopy, analytical ultracentrifugation). The results found for citrate synthase are also compared with previous findings for malate synthase, an enzyme of similar enzymatic function. Above all, this study shows that care has to be taken when studying small conformational changes. It is absolutely necessary to use different methods and conditions and to study the problem from different points of view to avoid pitfalls. (orig.)
Six-dimensional real and reciprocal space small-angle X-ray scattering tomography.
Schaff, Florian; Bech, Martin; Zaslansky, Paul; Jud, Christoph; Liebi, Marianne; Guizar-Sicairos, Manuel; Pfeiffer, Franz
2015-11-19
When used in combination with raster scanning, small-angle X-ray scattering (SAXS) has proven to be a valuable imaging technique of the nanoscale, for example of bone, teeth and brain matter. Although two-dimensional projection imaging has been used to characterize various materials successfully, its three-dimensional extension, SAXS computed tomography, poses substantial challenges, which have yet to be overcome. Previous work using SAXS computed tomography was unable to preserve oriented SAXS signals during reconstruction. Here we present a solution to this problem and obtain a complete SAXS computed tomography, which preserves oriented scattering information. By introducing virtual tomography axes, we take advantage of the two-dimensional SAXS information recorded on an area detector and use it to reconstruct the full three-dimensional scattering distribution in reciprocal space for each voxel of the three-dimensional object in real space. The presented method could be of interest for a combined six-dimensional real and reciprocal space characterization of mesoscopic materials with hierarchically structured features with length scales ranging from a few nanometres to a few millimetres--for example, biomaterials such as bone or teeth, or functional materials such as fuel-cell or battery components.
On small-angle neutron scattering from microemulsion droplets: the role of shape fluctuations
International Nuclear Information System (INIS)
Lisy, V.; Brutovsky, B.
2001-01-01
The form factor and intensity of static neutron scattering from microemulsion droplets are calculated. The droplet is modeled by a double-layered sphere consisting of a fluid core and a thin surfactant layer, immersed in another fluid. All the three components are incompressible and characterized by different scattering length densities. As distinct from previous descriptions of small-angle neutron scattering (SANS), we consistently take into account thermal fluctuations of the droplet shape, to the second order of the fluctuations of the droplet radius. The properties of the layer are described within Helfrich's concept of the elasticity of curved interfaces. It is shown that in many cases the account for the fluctuations is essential for the interpretation of SANS. Information about two elastic constants k and k bar (so far extracted from the experiments in the combination 2k + k bar) can be now simultaneously obtained from SANS for the system in conditions of two-phase coexistence. As an illustration, the theory is applied for the quantitative description of SANS experiments from the literature
Resolution effects and analysis of small-angle neutron scattering data
DEFF Research Database (Denmark)
Pedersen, J.S.
1993-01-01
A discussion of the instrumental smearing effects for small-angle neutron scattering (SANS) data sets is given. It is shown that these effects can be described by a resolution function, which describes the distribution of scattering vectors probed for the nominal values of the scattering vector...
Small-angle neutron scattering at pulsed spallation sources
International Nuclear Information System (INIS)
Seeger, P.A.; Hjelm, R.P. Jr.
1991-01-01
The importance of small-angle neutron scattering (SANS) in biological, chemical, physical and engineering research mandates that all intense neutron sources be equipped with SANS instruments. Four existing instruments at pulsed sources are described and the general differences between pulsed-source and reactor-based instrument designs are discussed. The basic geometries are identical, but dynamic range is generally achieved by using a broad band of wavelengths (with time-of-flight analysis) rather than by moving the detector. This allows optimization for maximum beam intensity at a given beam size over the full dynamic range with fixed collimation. Data-acquisition requirements at a pulsed source are more severe, requiring large fast histrograming memories. Data reduction is also more complex, as all wavelength-dependent and angle-dependent backgrounds and nonlinearities must be accounted for before data can be transformed to intensity vs momentum transfer (Q). A comparison is shown between the Los Alamos pulsed instrument and D11 (Institut Laue-Langevin) and examples from the four major topics of the conference are shown. The general conclusion is that reactor-based instruments remain superior at very low Q or if only a narrow range of Q is required, but that the current generation of pulsed-source instruments is competitive of moderate Q and may be faster when a wide range of Q is required. (orig.)
Magnetic nanoparticles studied by small angle X-ray scattering
International Nuclear Information System (INIS)
Oliveira, Cristiano Luis Pinto; Antonel, Soledad; Negri, Martin
2011-01-01
because they exhibit magnetic (ferromagnetic) and electrical properties in the same material. Then, the nickel nanoparticles could be used for the development of electroelastic materials. In this case, the electrical conductivity of the material can be strongly dependent on the applied magnetic field, for example the case of nickel metal nanoparticles dispersed in a polymer, resulting in an anisotropic material with combined piezomagnetic and piezoelectric properties. In order to investigate the structural characteristics of cobalt-iron oxides and nickel nanoparticles, powder samples of those magnetic materials were studied by Small-Angle X-Ray Scattering. As will be shown, from the analysis and modeling of the scattering data, structural information could be obtained, enabling a detailed description of the structural properties of the studied samples which could be directly correlated to the magnetic properties. (author)
Magnetic nanoparticles studied by small angle X-ray scattering
Energy Technology Data Exchange (ETDEWEB)
Oliveira, Cristiano Luis Pinto [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Grupo de Fluidos Complexos; Antonel, Soledad; Negri, Martin [Universidad de Buenos Aires (UBA) (Argentina). Facultad de Ciencias Exactas y Naturales. Dept. de Quimica Inorganica, Analitica y Quimica Fisica
2011-07-01
nanoparticles are very interesting because they exhibit magnetic (ferromagnetic) and electrical properties in the same material. Then, the nickel nanoparticles could be used for the development of electroelastic materials. In this case, the electrical conductivity of the material can be strongly dependent on the applied magnetic field, for example the case of nickel metal nanoparticles dispersed in a polymer, resulting in an anisotropic material with combined piezomagnetic and piezoelectric properties. In order to investigate the structural characteristics of cobalt-iron oxides and nickel nanoparticles, powder samples of those magnetic materials were studied by Small-Angle X-Ray Scattering. As will be shown, from the analysis and modeling of the scattering data, structural information could be obtained, enabling a detailed description of the structural properties of the studied samples which could be directly correlated to the magnetic properties. (author)
Scattering of a spherical pulse from a small inhomogeneity ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging Solutions)
Perturbations in elastic constants and density distinguish a volume inhomogeneity from its homoge- neous surroundings. The equation of motion for the first order scattering is studied in the perturbed medium. The scattered waves are generated by the interaction between the primary waves and the inhomogeneity.
Structural dissection of human metapneumovirus phosphoprotein using small angle x-ray scattering.
Renner, Max; Paesen, Guido C; Grison, Claire M; Granier, Sébastien; Grimes, Jonathan M; Leyrat, Cédric
2017-11-01
The phosphoprotein (P) is the main and essential cofactor of the RNA polymerase (L) of non-segmented, negative-strand RNA viruses. P positions the viral polymerase onto its nucleoprotein-RNA template and acts as a chaperone of the nucleoprotein (N), thereby preventing nonspecific encapsidation of cellular RNAs. The phosphoprotein of human metapneumovirus (HMPV) forms homotetramers composed of a stable oligomerization domain (P core ) flanked by large intrinsically disordered regions (IDRs). Here we combined x-ray crystallography of P core with small angle x-ray scattering (SAXS)-based ensemble modeling of the full-length P protein and several of its fragments to provide a structural description of P that captures its dynamic character, and highlights the presence of varyingly stable structural elements within the IDRs. We discuss the implications of the structural properties of HMPV P for the assembly and functioning of the viral transcription/replication machinery.
Small Angle Neutron Scattering experiments on ``side-on fixed"" liquid crystal polyacrylates
Leroux, N.; Keller, P.; Achard, M. F.; Noirez, L.; Hardouin, F.
1993-08-01
Small Angle Neutron Scattering experiments were carried out on liquid crystalline “side-on fixed” polyacrylates : we observe that the polymer backbone adopts a prolate conformation in the nematic phase. Such anisotropy of the global backbone is larger for smaller spacer length. In every case we measure at low temperatures a large chain extension as previously described in polysiloxanes. Par diffusion des neutrons aux petits angles nous observons que la chaîne de polyacrylates “en haltère” adopte une conformation type prolate en phase nématique. Son anisotropie est d'autant plus grande que l'espaceur est plus court. Dans tous les cas, nous retrouvons à basse température la forte extension de la chaîne polymère qui fut d'abord révélée dans les polysiloxanes.
TOF-SEMSANS—Time-of-flight spin-echo modulated small-angle neutron scattering
Strobl, M.; Tremsin, A.S.; Hilger, A.; Wieder, F.; Kardjilov, N.; Manke, I.; Bouwman, W.G.; Plomp, J.
2012-01-01
We report on measurements of spatial beam modulation of a polarized neutron beam induced by triangular precession regions in time-of-flight mode and the application of this novel technique spin-echo modulated small-angle neutron scattering (SEMSANS) to small-angle neutron scattering in the very
Small angle neutron and x-ray scattering studies of self-assembled nano structured materials
International Nuclear Information System (INIS)
Choi, Sung Min
2009-01-01
Full text: Small angle neutron and x-ray scattering are very powerful techniques to investigate nano structured materials. In this presentation, examples of nano structured materials investigated by neutron and x-ray scattering will be presented. Part I: The unique anisotropic physical properties of columnar discotic liquid crystals (DLCs) have attracted considerable interest for their potential applications as electronic devices. For many practical applications, however, it is crucial to obtain uniaxially oriented and highly ordered columnar superstructures of DLC molecules covering macroscopic area. Here, we present a simple and straight-forward approach to fabricate uniaxially oriented and highly ordered columnar superstructures of cobalt octa(n-decylthio) porphyrazine (CoS 1 0), a discotic supra-molecule, in bulk and on substrates [1] over a macroscopic length scale, utilizing an applied magnetic field and the interaction of CoS 1 0 with an OTS-functionalized substrate. The details of the oriented and ordered columnar nano-structures are investigated by SANS and GISAXS. Part II: Self-assembly of one-dimensional (1D) nanoparticles with metallic or semiconducting properties into highly ordered superstructures using various interactions has been of great interest as a route towards materials with new functionalities. Here, we report a new phase diagram of negatively charged 1D nanoparticle (cROD) and cationic liposome (CL) complexes in water which exhibit three different highly ordered phases [2]. Small angle neutron and x-ray scattering measurements show that the cROD-CL complexes exhibit three different highly ordered phases, intercalated lamellar, doubly intercalated lamellar and centered rectangular phases, depending on particle curvature and electrostatic interactions. The new phase diagram can be used to understand and design new highly ordered self-assemblies of 1D nanoparticles in soft matter which provide new functionalities. (author)
Energy Technology Data Exchange (ETDEWEB)
Raut Dessai, R., E-mail: reshooin@yahoo.com [Department of Physics, Goa University, Taleigao Plateau, Goa 403 206 (India); Desa, J.A.E. [Department of Physics, Goa University, Taleigao Plateau, Goa 403 206 (India); Sen, D.; Mazumder, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
2013-07-05
Highlights: ► A porous ceramic has been prepared from silica obtained from rice husk. ► The ceramic has a hierarchical pore structure from micrometric to nano-metric. ► Small Angle Neutron Scattering data indicate nano-pore connectivity to micro-pores. ► Pore morphology can be tuned by compaction pressure and sintering temperature. -- Abstract: Ceramic powder has been synthesized from rice husk as the source of silica. In order to probe the evolution of its hierarchical mesoscopic and microscopic porous structure, the ceramic powder was compacted at different pressures and was sintered at different temperatures. A glassy ceramic to crystalline transition under thermal treatment (up to 1000 °C) was revealed by X-ray diffraction. Existence of pores in two widely separated length scales was indicated by small angle neutron scattering with the smaller ones having mass fractal arrangement. Although no significant change in small pore structure under thermal effect was indicated, a significant modification of the same has been revealed by small angle neutron scattering at different compaction pressures. Connectivity between the pores was ascertained from scattering experiments on the ceramic compact impregnated with heavy water. Scanning electron microscopy shows the microstructure to undergo appreciable coalescence of micrometric ceramic particles for sintering temperature and pressure changes.
Theoretical study of the influence of small angle scattering on diffraction enhanced imaging
Energy Technology Data Exchange (ETDEWEB)
Zhu Peiping [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China)], E-mail: zhupp@ihep.ac.cn; Huang Wanxia; Yuan, Qingxi [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Wang Junyue; Shu Hang [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Graduate School of the Chinese Academy of Sciences, 100864 Beijing (China); Chen Bo [Department of Physics, University of Science and Technology of China, Hefei 230026 (China); Wu Ziyu [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China)], E-mail: wuzy@ihep.ac.cn
2007-07-15
Small angle scattering plays an important role in diffraction enhanced imaging (DEI). The DEI equation proposed by Chapman is accepted and widely used by many applications in medical, biological and material researches. However, in this framework the contribution of the small angle scattering determined by the crystal analyzer is neglected and the extinction contrast caused by the rejection of the small angle scattering by the analyzer is not explicitly expressed. In this contribution we introduce two additional terms in the DEI equation that describe the additional background introduced by the small angle scattering collected by the analyzer crystal and the extinction contrast associated to the rejection of the small angle scattering by the analyzer crystal, respectively. Four kinds of images of the DEI method were considered by using these revised equations and results were presented and discussed.
Theoretical study of the influence of small angle scattering on diffraction enhanced imaging
International Nuclear Information System (INIS)
Zhu Peiping; Huang Wanxia; Yuan, Qingxi; Wang Junyue; Shu Hang; Chen Bo; Wu Ziyu
2007-01-01
Small angle scattering plays an important role in diffraction enhanced imaging (DEI). The DEI equation proposed by Chapman is accepted and widely used by many applications in medical, biological and material researches. However, in this framework the contribution of the small angle scattering determined by the crystal analyzer is neglected and the extinction contrast caused by the rejection of the small angle scattering by the analyzer is not explicitly expressed. In this contribution we introduce two additional terms in the DEI equation that describe the additional background introduced by the small angle scattering collected by the analyzer crystal and the extinction contrast associated to the rejection of the small angle scattering by the analyzer crystal, respectively. Four kinds of images of the DEI method were considered by using these revised equations and results were presented and discussed
Experimental light scattering by small particles in Amsterdam and Granada
Directory of Open Access Journals (Sweden)
Volten H.
2010-06-01
Full Text Available We report on two light scattering instruments located in Amsterdam and Granada, respectively. These instruments enable measuring scattering matrices as functions of the scattering angle of collections of randomly orieneted irregular particles. In the past decades, the experimental setup located in Amsterdam, The Netherlands, has produced a significant amount of experimental data. Unfortunately, this setup was officially closed a couple of years ago. We also present a modernized descendant of the Dutch experimental setup recently constructed at the Instituto de Astrofísica de Andalucía (IAA in Granada, Spain. We give a brief description of the instruments, and present some representative results.
International Nuclear Information System (INIS)
McCray, John; Navarre-Sitchler, Alexis; Mouzakis, Katherine; Heath, Jason E.; Dewers, Thomas A.; Rother, Gernot
2010-01-01
Geological carbon sequestration relies on the principle that CO 2 injected deep into the subsurface is unable to leak to the atmosphere. Structural trapping by a relatively impermeable caprock (often mudstone such as a shale) is the main trapping mechanism that is currently relied on for the first hundreds of years. Many of the pores of the caprock are of micrometer to nanometer scale. However, the distribution, geometry and volume of porosity at these scales are poorly characterized. Differences in pore shape and size can cause variation in capillary properties and fluid transport resulting in fluid pathways with different capillary entry pressures in the same sample. Prediction of pore network properties for distinct geologic environments would result in significant advancement in our ability to model subsurface fluid flow. Specifically, prediction of fluid flow through caprocks of geologic CO 2 sequestration reservoirs is a critical step in evaluating the risk of leakage to overlying aquifers. The micro- and nanoporosity was analyzed in four mudstones using small angle neutron scattering (SANS). These mudstones are caprocks of formations that are currently under study or being used for carbon sequestration projects and include the Marine Tuscaloosa Group, the Lower Tuscaloosa Group, the upper and lower shale members of the Kirtland Formation, and the Pennsylvanian Gothic shale. Total organic carbon varies from <0.3% to 4% by weight. Expandable clay contents range from 10% to ∼40% in the Gothic shale and Kirtland Formation, respectively. Neutrons effectively scatter from interfaces between materials with differing scattering length density (i.e. minerals and pores). The intensity of scattered neutrons, I(Q), where Q is the scattering vector, gives information about the volume of pores and their arrangement in the sample. The slope of the scattering data when plotted as log I(Q) vs. log Q provides information about the fractality or geometry of the pore network
Energy Technology Data Exchange (ETDEWEB)
McCray, John (Colorado School of Mines); Navarre-Sitchler, Alexis (Colorado School of Mines); Mouzakis, Katherine (Colorado School of Mines); Heath, Jason E.; Dewers, Thomas A.; Rother, Gernot (Oak Ridge National Laboratory)
2010-11-01
Geological carbon sequestration relies on the principle that CO{sub 2} injected deep into the subsurface is unable to leak to the atmosphere. Structural trapping by a relatively impermeable caprock (often mudstone such as a shale) is the main trapping mechanism that is currently relied on for the first hundreds of years. Many of the pores of the caprock are of micrometer to nanometer scale. However, the distribution, geometry and volume of porosity at these scales are poorly characterized. Differences in pore shape and size can cause variation in capillary properties and fluid transport resulting in fluid pathways with different capillary entry pressures in the same sample. Prediction of pore network properties for distinct geologic environments would result in significant advancement in our ability to model subsurface fluid flow. Specifically, prediction of fluid flow through caprocks of geologic CO{sub 2} sequestration reservoirs is a critical step in evaluating the risk of leakage to overlying aquifers. The micro- and nanoporosity was analyzed in four mudstones using small angle neutron scattering (SANS). These mudstones are caprocks of formations that are currently under study or being used for carbon sequestration projects and include the Marine Tuscaloosa Group, the Lower Tuscaloosa Group, the upper and lower shale members of the Kirtland Formation, and the Pennsylvanian Gothic shale. Total organic carbon varies from <0.3% to 4% by weight. Expandable clay contents range from 10% to {approx}40% in the Gothic shale and Kirtland Formation, respectively. Neutrons effectively scatter from interfaces between materials with differing scattering length density (i.e. minerals and pores). The intensity of scattered neutrons, I(Q), where Q is the scattering vector, gives information about the volume of pores and their arrangement in the sample. The slope of the scattering data when plotted as log I(Q) vs. log Q provides information about the fractality or geometry of
Optical modeling of plasma-deposited ZnO films: Electron scattering at different length scales
International Nuclear Information System (INIS)
Knoops, Harm C. M.; Loo, Bas W. H. van de; Smit, Sjoerd; Ponomarev, Mikhail V.; Weber, Jan-Willem; Sharma, Kashish; Kessels, Wilhelmus M. M.; Creatore, Mariadriana
2015-01-01
In this work, an optical modeling study on electron scattering mechanisms in plasma-deposited ZnO layers is presented. Because various applications of ZnO films pose a limit on the electron carrier density due to its effect on the film transmittance, higher electron mobility values are generally preferred instead. Hence, insights into the electron scattering contributions affecting the carrier mobility are required. In optical models, the Drude oscillator is adopted to represent the free-electron contribution and the obtained optical mobility can be then correlated with the macroscopic material properties. However, the influence of scattering phenomena on the optical mobility depends on the considered range of photon energy. For example, the grain-boundary scattering is generally not probed by means of optical measurements and the ionized-impurity scattering contribution decreases toward higher photon energies. To understand this frequency dependence and quantify contributions from different scattering phenomena to the mobility, several case studies were analyzed in this work by means of spectroscopic ellipsometry and Fourier transform infrared (IR) spectroscopy. The obtained electrical parameters were compared to the results inferred by Hall measurements. For intrinsic ZnO (i-ZnO), the in-grain mobility was obtained by fitting reflection data with a normal Drude model in the IR range. For Al-doped ZnO (Al:ZnO), besides a normal Drude fit in the IR range, an Extended Drude fit in the UV-vis range could be used to obtain the in-grain mobility. Scattering mechanisms for a thickness series of Al:ZnO films were discerned using the more intuitive parameter “scattering frequency” instead of the parameter “mobility”. The interaction distance concept was introduced to give a physical interpretation to the frequency dependence of the scattering frequency. This physical interpretation furthermore allows the prediction of which Drude models can be used in a specific
A high-accuracy extraction of the isoscalar πN scattering length from pionic deuterium data
International Nuclear Information System (INIS)
Phillips, Daniel R.; Baru, Vadim; Hanhart, Christoph; Nogga, Andreas; Hoferichter, Martin; Kubis, Bastian
2010-01-01
We present a high-accuracy calculation of the π(bar sign)d scattering length using chiral perturbation theory up to order (M π /m p ) 7/2 . For the first time isospin-violating corrections are included consistently. The resulting value of a π -bar d has a theoretical uncertainty of a few percent. We use it, together with data on pionic deuterium and pionic hydrogen atoms, to extract the isoscalar and isovector pion-nucleon scattering lengths from a combined analysis, and obtain a + (7.9±3.2)·10 -3 M π -1 and a-bar (86.3±1.0)·10 -3 M π -1 .
Precision determination of the πN scattering lengths and the charged πNN coupling constant
International Nuclear Information System (INIS)
Ericson, T.E.O.; Loiseau, B.; Thomas, A.W.
2000-01-01
We critically evaluate the isovector GMO sumrule for the charged πNN coupling constant using recent precision data from π - p and π - d atoms and with careful attention to systematic errors. From the π - d scattering length we deduce the pion-proton scattering lengths ((1)/(2))(a π - p + a π - n ) = (-20 ± 6(statistic)±10 (systematic) ·10 -4 m -1 π c and ((1)/(2))(a π - p - a π - n ) = (903 ± 14) · 10 -4 m -1 π c . From this a direct evaluation gives g 2 c (GMO)/4π = 14.20 ± 0.07 (statistic)±0.13(systematic) or f 2 c /4π = 0.0786 ± 0.0008
Small-angle neutron scattering investigation of polyurethane aged in dry and wet air
Directory of Open Access Journals (Sweden)
Q. Tian
2014-05-01
Full Text Available The microstructures of Estane 5703 aged at 70°C in dry and wet air have been studied by small-angle neutron scattering. The samples were swollen in deuterated toluene for enhancing the contrast. The scattering data show the characteristic domain structure of polyurethanes consisting of soft and hard segments. Debye-Anderson-Brumberger function used with hard sphere structure factor, and the Teubner-Strey model are used to analyze the two-phase domain structure of the polymer. The combined effects of temperature and humidity have a strong disruption effect on the microstructures of Estane. For the sample aged at 70°C in wet air for 1 month, the domain size, described by the correlation length, increases from 2.3 to 3.8 nm and their distance, expressed by hard-sphere interaction radius, increases from 8.4 to 10.6 nm. The structure development is attributed to degradation of polymer chains as revealed by gel permeation chromatography. The hydrolysis of ester links on polymer backbone at 70°C in the presence of water humidity is the main reason for the changes of the microstructure. These findings can contribute to developing predictive models for the safety, performance, and lifetime of polyurethanes.
Structural evaluation of an amyloid fibril model using small-angle x-ray scattering
Dahal, Eshan; Choi, Mina; Alam, Nadia; Bhirde, Ashwinkumar A.; Beaucage, Serge L.; Badano, Aldo
2017-08-01
Amyloid fibrils are highly structured protein aggregates associated with a wide range of diseases including Alzheimer’s and Parkinson’s. We report a structural investigation of an amyloid fibril model prepared from a commonly used plasma protein (bovine serum albumin (BSA)) using small-angle x-ray scattering (SAXS) technique. As a reference, the size estimates from SAXS are compared to dynamic light scattering (DLS) data and the presence of amyloid-like fibrils is confirmed using Congo red absorbance assay. Our SAXS results consistently show the structural transformation of BSA from spheroid to rod-like elongated structures during the fibril formation process. We observe the elongation of fibrils over two months with fibril length growing from 35.9 ± 3.0 nm to 51.5 ± 2.1 nm. Structurally metastable fibrils with distinct SAXS profiles have been identified. As proof of concept, we demonstrate the use of such distinct SAXS profiles to detect fibrils in the mixture solutions of two species by estimating their volume fractions. This easily detectable and well-characterized amyloid fibril model from BSA can be readily used as a control or standard reference to further investigate SAXS applications in the detection of structurally diverse amyloid fibrils associated with protein aggregation diseases.
Transport cross section for small-angle scattering
International Nuclear Information System (INIS)
D'yakonov, M.I.; Khaetskii, A.V.
1991-01-01
Classical mechanics is valid for describing potential scattering under the conditions (1) λ much-lt α and (2) U much-gt ℎυ/α, where λ is the de Broglie wavelength, α is the characteristic size of the scatterer, U is the characteristic value of the potential energy, and υ is the velocity of the scattered particle. The second of these conditions means that the typical value of the classical scattering angle is far larger than the diffraction angle λ/α. In this paper the authors show that this second condition need not hold in a derivation of the transport cross section. In other words, provided that the condition λ much-lt α holds, it is always possible to calculate the transport cross section from the expressions of classical mechanics, even in the region U approx-lt ℎυ/α, where the scattering is diffractive,and the differential cross section is greatly different from the classical cross section. The transport cross section is found from the classical expression even in the anticlassical case U much-lt ℎυ/α, where the Born approximation can be used
International Nuclear Information System (INIS)
Oba, Yojiro; Koppoju, Suresh; Ohnuma, Masato; Kinjo, Yuki; Tomota, Yo; Morooka, Satoshi; Suzuki, Jun-ichi; Yamaguchi, Daisuke; Koizumi, Satoshi; Sato, Masugu; Shiraga, Tetsuo
2012-01-01
The microstructure of inclusions in low carbon free cutting steel without lead addition was investigated using small-angle X-ray scattering (SAXS) coupled with small-angle neutron scattering (SANS). The two-dimensional (2D) SAXS pattern shows clear scattering due to inclusions composed of large elongated particles aligned along the rolling direction, and small isotropic particles. From a comparison of the simulated and experimental 2D SAXS patterns, the shapes of the inclusions are regarded as ellipsoid for the larger inclusions and spherical for the smaller inclusions. The length of the minor axis in the large inclusion is 6.9 μm, while the diameter of the small inclusion is 0.50 μm. The aspect ratio of the large inclusion is estimated to be 3.8 in the lower q region, and is reduced slightly to 3.5 in the higher q region from the azimuthal plots. The results of an alloy contrast variation (ACV) analysis using both the SAXS and SANS data indicate that the chemical composition of the inclusions is almost NaCl-type manganese sulfide, and that the amount of iron sulfide is low. The volume fractions are 1.4% for the large inclusions and 0.2% for the small inclusions. This is consistent with the area fraction estimated using an optical microscope, and indicates that nearly all of the sulfur in the steel sample forms the manganese sulfide inclusions. (author)
Small-angle scattering theory revisited: Photocurrent and spatial localization
DEFF Research Database (Denmark)
Basse, N.P.; Zoletnik, S.; Michelsen, Poul
2005-01-01
In this paper theory on collective scattering measurements of electron density fluctuations in fusion plasmas is revisited. We present the first full derivation of the expression for the photocurrent beginning at the basic scattering concepts. Thereafter we derive detailed expressions for the auto......- and crosspower spectra obtained from measurements. These are discussed and simple simulations made to elucidate the physical meaning of the findings. In this context, the known methods of obtaining spatial localization are discussed and appraised. Where actual numbers are applied, we utilize quantities from two...
Scattering by ensembles of small particles experiment, theory and application
Gustafson, B. A. S.
1980-01-01
A hypothetical self consistent picture of evolution of prestellar intertellar dust through a comet phase leads to predictions about the composition of the circum-solar dust cloud. Scattering properties of thus resulting conglomerates with a bird's-nest type of structure are investigated using a micro-wave analogue technique. Approximate theoretical methods of general interest are developed which compared favorably with the experimental results. The principal features of scattering of visible radiation by zodiacal light particles are reasonably reproduced. A component which is suggestive of (ALPHA)-meteoroids is also predicted.
Scattering by ensembles of small particles experiment, theory and application
International Nuclear Information System (INIS)
Gustafson, B.Aa.S.
1980-01-01
A hypothetical selfconsistent picture of evolution of prestellar interstellar dust through a comet phase leades to predictions about the composition of the circum-solar dust cloud. Scattering properties of thus resulting conglomerates with a bird's-nest type of structure are investigated using a micro-wave analogue technique. Approximate theoretical methods of general interest are developed which compared favorably with the experimental results. The principal features of scattering of visible radiation by zodiacal light particles are reasonably reproduced. A component which is suggestive of β-meteoroids is also predicted. (author)
Scattering of light from small nematic spheres with radial dielectric anisotropy
International Nuclear Information System (INIS)
Karacali, H.; Risser, S.M.; Ferris, K.F.
1997-01-01
We have calculated the scattering cross sections of small anisotropic nematic droplets embedded in a polymer matrix as a function of the dielectric constants of the nematic and the polymer. We have derived the general form for the Helmholtz wave equation for a droplet which has spatially varying radial anisotropy, and have explicitly solved this equation for three distinct models of the dielectric anisotropy, including one model where the anisotropy increases linearly with droplet radius. Numerical calculations of the scattering amplitudes for droplets much smaller than the wavelength of the incident radiation show that droplets with continual variation in the dielectric anisotropy have much larger scattering amplitude than droplets with fixed anisotropy. The scattering from droplets with linearly varying anisotropy exhibits a scattering minimum for much smaller polymer dielectric constants than the other models. These results show that the scattering from small anisotropic droplets is sensitive to details of the internal structure and anisotropy of the droplet. copyright 1997 The American Physical Society
Small angle scattering from soft matter-application to complex mixed systems
International Nuclear Information System (INIS)
Boue, F.; Cousin, F.; Gummel, J.; Carrot, G.; El Harrak, A.; Oberdisse, J.
2007-01-01
The advantage of small angle neutron scattering associated with isotopic labelling through deuteration is illustrated in the case of mixed systems, created by associating already well-known systems of characteristic structures; this is also important for applications. Our first mixed system associates charged polymer chains, polyelectrolyte (here polystyrene sulfonate, PSS), with oppositely charged particles, proteins (here lysozyme). Different fractions of deuterated water (D 2 O) mixed with normal water are used to match the scattering length density of the protein or of the polymer in non-deuterated or deuterated version. First, this allows us to separate the protein and the polymer signal: we can then distinguish a case where the structures of each species alone in water are hardly modified by mixing, except for interconnections yielding a gel, and a case inducing complete change into a structure common to both species, made of aggregated globules. Secondly, using, for counter-ions of the poly-ions, deuterated Tetramethylammonium, together with matching both protein and polymer, we establish unambiguously the counter-ion release into the solvent. Thirdly, matching only a fraction of polymer chains, the other being deuterated, we extrapolate at zero deuterated fraction their form factor and describe the chain conformation inside the complexes. Fourthly, we illustrate the possibilities of modelling the signal on a second example of mixed system: a nano-composite made of silica particles surrounded by polymer dispersed into a deuterated polymer matrix. Chains are then visible in such reinforced polymer system, in particular when it is submitted to elongation: we discuss a possible model for an ideal system, introducing the scattering contribution from deformed chains. (authors)
M. Chad Bolding; Bobby L. Lanford
2005-01-01
Currently, there is a lack of information concerning mechanical forest fuel reduction. This study examined and measured the feasibility of ground-based mechanical harvesting to reduce forest fuel buildup and produce energywood. Cut-to-length (CTL) harvesting coupled with a small in-woods chipper provided a low impact way to harvest pre-commercial trees and tops along...
DEFF Research Database (Denmark)
Yaron, U.; Gammel, P.L.; Boebinger, G.S.
1997-01-01
Small angle neutron scattering studies of the flux line lattice (FLL) in UPt3 for fields H perpendicular to c provide direct microscopic evidence for the 5 kOe B --> C transition. We find a pronounced maximum in the longitudinal correlation length of the FLL at the transition and an abrupt change...
Collimator scatter and 2D dosimetry in small proton beams
van Luijk, P.; van 't Veld, A.A.; Zelle, H.D.; Schippers, J.M.
Monte Carlo simulations have been performed to determine the influence of collimator-scattered protons from a 150 MeV proton beam on the dose distribution behind a collimator. Slit-shaped collimators with apertures between 2 and 20 mm have been simulated. The Monte Carlo code GEANT 3.21 has been
Small angle X-ray scattering from protein in solution
International Nuclear Information System (INIS)
Souza, C.F. de; Torriani, I.L.
1988-01-01
In this work we report experiments performed with giant respiratory proteins from annelids. X-ray scattering data were obtained both by the use of conventional rotating anod source and synchotron radiation. Data from solutions with several protein concentrations were analyzed. (A.C.A.S.) [pt
Rakotonarivo , Sandrine; Walker , S.C.; Kuperman , W. A.; Roux , Philippe
2011-01-01
International audience; A method to actively localize a small perturbation in a multiple scattering medium using a collection of remote acoustic sensors is presented. The approach requires only minimal modeling and no knowledge of the scatterer distribution and properties of the scattering medium and the perturbation. The medium is ensonified before and after a perturbation is introduced. The coherent difference between the measured signals then reveals all field components that have interact...
Proceedings of the International school and symposium on small angle scattering
International Nuclear Information System (INIS)
Borbely, S.; Rosta, L.
1999-04-01
The meeting was devoted to small angle neutron and X-ray scattering with regard to the wide interest for this method in various fields of basic and applied research. Scientists from European laboratories gave introductory talks to various subject fields related to small angle scattering (SAS) techniques or data analysis methods as well as topical research area e.g. soft condensed matter, biology or materials science. An important number of contributed talks were presented on neutron or X-ray scattering and even on combining both of them, demonstrating the very useful complementarity of these methods. Some other papers give nice examples of SAS experiments completed by results of other techniques such as NMRE of light scattering. The variety of presented contributions is a nice demonstration for the interdisciplinary use of small angle scattering from physics through biology, chemistry, materials science to engineering. 18 items are indexed separately for the INIS database. (K.A.)
International Nuclear Information System (INIS)
Iashina, E G; Grigoriev, S V; Bouwman, W G; Duif, C P; Filatov, M V
2017-01-01
Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrometer length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei which is well fitted by the exponential function G ( z ) = exp(− z / ξ ), where ξ is the correlation length of a nucleus (in experimental data ξ = 3, 3 μ m). The exponential decay of G ( z ) corresponds to the logarithmic pair correlation function γ ( r ) = ln( ξ / r ). As the sensitivity of the SESANS signal depends on the neutron wavelength, we propose the SESANS setup with the changeable wavelength in the range from 2 to 12 Å. Such option allows one to study in great detail the internal structure of the biological cell in the length scale from 10 −2 μ m to 10 μ m. (paper)
Iashina, E. G.; Bouwman, W. G.; Duif, C. P.; Filatov, M. V.; Grigoriev, S. V.
2017-06-01
Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrmeter length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei which is well fitted by the exponential function G(z) = exp(-z/ξ), where ξ is the correlation length of a nucleus (in experimental data ξ = 3, 3 μm). The exponential decay of G(z) corresponds to the logarithmic pair correlation function γ(r) = ln(ξ/r). As the sensitivity of the SESANS signal depends on the neutron wavelength, we propose the SESANS setup with the changeable wavelength in the range from 2 to 12 Å. Such option allows one to study in great detail the internal structure of the biological cell in the length scale from 10-2 μm to 10 μm.
Small-angle scattering from GP zones in Al–Cu alloy
Indian Academy of Sciences (India)
... and smallangle scattering experiments were carried on the powdered samples as a function of time during artificial aging. Small-angle scattering data were analysed, and evidence has been obtained for the occurrence of spinodal decomposition as the mechanism responsible in the early stages of formation of GP zones.
Small-angle neutron-scattering studies of the magnetic phase diagram of MnSi
DEFF Research Database (Denmark)
Harris, P.; Lebech, B.; Hae Seop Shim
1995-01-01
The antiferromagnetic order of MnSi has been studied as function of temperature and applied magnetic field using small-angle neutron scattering. The results were analyzed using the three-dimensional resolution function and the scattering cross-section to model the diffraction data. Physical...
A mechanical velocity selector for a small angle scattering instrument on a pulsed neutron source
International Nuclear Information System (INIS)
Meardon, B.H.; Stewart, R.J.; Williams, W.G.
1978-11-01
Design parameters and performance calculations are given for a straight-slot velocity selector which can be used for discriminating between elastic and inelastic scattering events in small angle scattering experiments on a pulsed neutron source. The selector has a high transmittance over the wavelength range 3 A 5%. (author)
Stieger, M.A.; Richtering, W.; Pedersen, J.S.; Lindner, P.
2004-01-01
The structure of temperature-sensitive poly(N-isopropylacrylamide) microgels in dilute suspension was investigated by means of small-angle neutron scattering. A direct modeling expression for the scattering intensity distribution was derived which describes very well the experimental data at all
International Nuclear Information System (INIS)
Blau, R.; Rosenberg, L.; Spruch, L.
1977-01-01
A minimum principle for the calculation of the scattering length, applicable when the ground-state wave function of the target system is known precisely, has been available for some time. When, as is almost always the case, the target wave function is imprecisely known, a minimum principle is available but the simple minimum principle noted above is not applicable. Further, as recent calculations show, numerical instabilities usually arise which severely limit the utility of even an ordinary variational approach. The difficulty, which can be traced to the appearance of singularities in the variational construction, is here removed through the introduction of a minimum principle, not for the true scattering length, but for one associated with a closely connected problem. This guarantees that no instability difficulties can arise as the trial scattering wave function and the trial target wave function are improved. The calculations are little different from those required when the target ground-state wave function is known, and, in fact, the original version of the minimum principle is recovered as the trial target wave function becomes exact. A careful discussion is given of the types of problems to which the method can be applied. In particular, the effects of the Pauli principle, and the existence of a finite number of composite bound states, can be accounted for
Box, M. A.; Deepak, A.
1981-01-01
The propagation of photons in a medium with strongly anisotropic scattering is a problem with a considerable history. Like the propagation of electrons in metal foils, it may be solved in the small-angle scattering approximation by the use of Fourier-transform techniques. In certain limiting cases, one may even obtain analytic expressions. This paper presents some of these results in a model-independent form and also illustrates them by the use of four different phase-function models. Sample calculations are provided for comparison purposes
Small angle X-ray scattering experiments with three-dimensional imaging gas detectors
International Nuclear Information System (INIS)
La Monaca, A.; Iannuzzi, M.; Messi, R.
1985-01-01
Measurements of small angle X-ray scattering of lupolen - R, dry collagen and dry cornea are presented. The experiments have been performed with synchrotron radiation and a new three-dimensional imaging drif-chamber gas detector
International Nuclear Information System (INIS)
Bulut, S.; Guelecyuez, M.C.; Kaskas, A.; Tezcan, C.
2007-01-01
H N and singular eigenfunction methods are used to determine the neutron distribution everywhere in a source-free half space with zero incident flux for a linearly anisotropic scattering kernel. The singular eigenfunction expansion of the method of elementary solutions is used. The orthogonality relations of the discrete and continuous eigenfunctions for linearly anisotropic scattering provides the determination of the expansion coefficients. Different expansions of the exit distribution are used: the expansion in powers of μ, the expansion in terms of Legendre polynomials and the expansion in powers of 1/(1+μ). The results are compared to each other. In the second part of our work, the transport equation and the infinite medium Green function are used. The numerical results of the extrapolation length obtained for the different expansions is discussed. (orig.)
International Nuclear Information System (INIS)
Soric, J C; Chen, P Y; Alù, A; Kerkhoff, A; Rainwater, D; Melin, K
2013-01-01
We present the first experimental realization and verification of a three-dimensional stand-alone mantle cloak designed to suppress the total scattering of a finite-length dielectric rod of moderate cross-section. Mantle cloaking has been proposed to realize ultralow-profile conformal covers that may achieve substantial camouflage, transparency and high-performance non-invasive near-field sensing. Here, we realize and verify a mantle cloak for radio-waves. We report an extensive campaign of far- and near-field free-space measurements demonstrating that conformal cloaks can indeed produce strong scattering suppression in all directions and over a relatively broad bandwidth of operation. (paper)
COUPLED-CHANNELS FADDEEV CALCULATION OF THE K(-) d SCATTERING LENGTH
Czech Academy of Sciences Publication Activity Database
Shevchenko, Nina V.
2011-01-01
Roč. 26, 3-4 (2011), s. 558-560 ISSN 0217-751X. [11th International Workshop on Meson Production , Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA AV ČR KJB100480801 Institutional research plan: CEZ:AV0Z10480505 Keywords : Few-body systems * multichannel scattering * antikaon-baryon interaction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.053, year: 2011
Scattering lengths in SU(2) gauge theory with two fundamental fermions
DEFF Research Database (Denmark)
Arthur, R.; Drach, V.; Hansen, Martin Rasmus Lundquist
2014-01-01
We investigate non perturbatively scattering properties of Goldstone Bosons in an SU(2) gauge theory with two Wilson fermions in the fundamental representation. Such a theory can be used to build extensions of the Standard Model that unifies Technicolor and pseudo Goldstone composite Higgs models...... the expected chiral symmetry breaking pattern. We then discuss how to compute them on the lattice and give preliminary results using finite size methods....
Small-angle neutron scattering from micellar solutions
Indian Academy of Sciences (India)
The aggregates formed are of various types, shapes and sizes such as spherical or ... 66. Pramana – J. Phys., Vol. 63, No. 1, July 2004 ... effect of (a) spacer length, (b) flexibility vs. rigidity of the spacer, (c) hydropho- bicity vs. hydrophilicity of ...
International Nuclear Information System (INIS)
Glatter, O.; Gruber, K.
1993-01-01
Indirect Fourier transformation is a widely used technique for the desmearing of instrumental broadening effects, for data smoothing and for Fourier transformation of small-angle scattering data. This technique, however, can only be applied to scattering curves with a band-limited Fourier transform, i.e. separated and noninteracting scattering centers. It can therefore not be used for scattering data from partially ordered systems. In this paper, a modified technique for partially ordered systems working in reciprocal space is presented. A peak-recognition technique allows its application to scattering functions with narrow peaks, such as the scattering functions of layered systems like lamellar stacks or strongly interacting particles. Arbitrary geometry effects and wavelength effects can be corrected. Examples of simulations show the merits and limits of this new method. One example shows its applicability to real data. (orig.)
Small-angle scattering of swift electrons and positrons in a crystal
International Nuclear Information System (INIS)
Kudrin, V.V.; Vorobiev, S.A.
1975-01-01
Features of small-angle scattering of charged particles by the crystal structure and two-dimensional angular distribution are studied on the basis of Monte-Carlo calculations of 20 MeV electron and positron transmission through a MgO single crystal. An accurate method for calculation of the charged particle scattering in a heterogeneous electron gas in the crystal is proposed. The analytical conditions under which the string-effect influences the small-angle scattering are derived and comparison is carried out with well-known experimental data. (author)
International Nuclear Information System (INIS)
Yano, M.; Manabe, A.; Shoji, T.; Kato, A.; Ono, K.; Harada, M.; Kohlbrecher, J.
2014-01-01
The magnetic reversal behaviors of single domain sized Nd-Fe-B permanent magnets, with and without isolation between the Nd 2 Fe 14 B grains, was clarified using small-angle neutron scattering (SANS). The SANS patterns obtained arose from changes in the magnetic domains and were analyzed using the Teubner–Stray model, a phenomenological correlation length model, to quantify the periodicity and morphology of the magnetic domains. The results indicated that the magnetic reversal evolved with the magnetic domains that had similar sized grains. The grain isolation enabled us to realize the reversals of single domains
Boundary asymptotics for a non-neutral electrochemistry model with small Debye length
Lee, Chiun-Chang; Ryham, Rolf J.
2018-04-01
This article addresses the boundary asymptotics of the electrostatic potential in non-neutral electrochemistry models with small Debye length in bounded domains. Under standard physical assumptions motivated by non-electroneutral phenomena in oxidation-reduction reactions, we show that the electrostatic potential asymptotically blows up at boundary points with respect to the bulk reference potential as the scaled Debye length tends to zero. The analysis gives a lower bound for the blow-up rate with respect to the model parameters. Moreover, the maximum potential difference over any compact subset of the physical domain vanishes exponentially in the zero-Debye-length limit. The results mathematically confirm the physical description that electrolyte solutions are electrically neutral in the bulk and are strongly electrically non-neutral near charged surfaces.
Energy Technology Data Exchange (ETDEWEB)
Trotter, D.E. Gonzalez [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: crowell@tunl.duke.edu; Meneses, F. Salinas [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: tornow@tunl.duke.edu; Crowell, A.S.; Howell, C.R. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Schmidt, D. [Physikalisch-Technische Bundesanstalt, D-38116, Braunschweig (Germany); Walter, R.L. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)
2009-02-11
The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the {sup 1}S{sub 0} neutron-neutron and neutron-proton scattering lengths a{sub nn} and a{sub np}, respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E{sub n}=13MeV.
International Nuclear Information System (INIS)
Trotter, D.E. Gonzalez; Meneses, F. Salinas; Tornow, W.; Crowell, A.S.; Howell, C.R.; Schmidt, D.; Walter, R.L.
2009-01-01
The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the 1 S 0 neutron-neutron and neutron-proton scattering lengths a nn and a np , respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E n =13MeV.
International Nuclear Information System (INIS)
Ioffe, A.; Ermakov, O.; Karpikhin, I.; Krupchitsky, P.; Mikula, P.; Lukas, P.; Vrana, M.
2000-01-01
The neutron scattering length of lead isotopes 204 Pb, 207 Pb and 208 Pb are determined by a set of neutron interferometry experiments. The obtained values b (208) =9.494(30) fm, b (207) =9.286(16) fm, b (204) =10.893(78) fm have much higher accuracy then current table data. Together with the precise value of b for natural lead, these results represent a complete set of data and allow one to calculate b (206) =9.221(69) fm, which is in the very good agreement with the present day experimental value. (orig.)
Lurton, T.; Renard, J.-B.; Vignelles, D.; Jeannot, M.; Akiki, R.; Mineau, J.-L.; Tonnelier, T.
2014-04-01
We have investigated the behaviour of light scattering by particulates of various sizes (0.1 μm to 100 μm) at a small scattering angle (below 20°). It has been previously shown that, for a small angle, the scattered intensities are weakly dependent upon the particulates' composition (Renard et al., 2010). Particles found in the atmosphere exhibit roughness that leads to large discrepancies with the classical Mie solution in terms of scattered intensities in the low angular set-up. This article focuses on building an effective theoretical tool to predict the behaviour of light scattering by real particulates at a small scattering angle. We present both the classical Mie theory and its adaptation to the case of rough particulates with a fairly simple roughness parameterisation. An experimental device was built, corresponding to the angular set-up of interest (low scattering angle and therefore low angular aperture). Measurements are presented that confirm the theoretical results with good agreement. It was found that differences between the classical Mie solution and actual measurements - especially for large particulates - can be attributed to the particulate roughness. It was also found that, in this low angular set-up, saturation of the scattered intensities occurs for relatively small values of the roughness parameter. This confirms the low variability in the scattered intensities observed for atmospheric particulates of different kinds. A direct interest of this study is a broadening of the dynamic range of optical counters: using a small angle of aperture for measurements allows greater dynamics in terms of particle size. Thus it allows a single device to observe a broad range of particle sizes whilst utilising the same electronics.
DEFF Research Database (Denmark)
Freltoft, T.; Kjems, Jørgen; Sinha, S. K.
1986-01-01
Small-angle neutron scattering from normal, compressed, and water-suspended powders of aggregates of fine silica particles has been studied. The samples possessed average densities ranging from 0.008 to 0.45 g/cm3. Assuming power-law correlations between particles and a finite correlation length ξ......, the authors derive the scattering function S(q) from specific models for particle-particle correlation in these systems. S(q) was found to provide a satisfactory fit to the data for all samples studied. The fractal dimension df corresponding to the power-law correlation was 2.61±0.1 for all dry samples, and 2...
International Nuclear Information System (INIS)
Bates, F.S.; Koehler, W.C.; Wignall, G.D.; Fetters, L.J.
1986-12-01
A well characterized binary mixture of normal (protonated) and perdeuterated monodisperse 1,2 polybutenes has been studied by small-angle neutron scattering (SANS). For scattering wavevectors q greater than the inverse radius-of-gyration R/sub g/ -1 , the SANS intensity is quantitatively predicted by the random phase approximation (RPA) theory of deGennes over all measured values of the segment-segment interaction parameter Chi. In the region (Chi s-Chi)Chi s -1 > 0.5 the interaction parameter determined using the RPA theory for q > R/sub g/ -1 is greater than that calculated from the zero-angle intensity based on an Ornstein-Zernike plot, where Chi s represents the limit of single phase stability. These findings indicate a correlation between the critical fluctuation length ξ and R/sub g/ which is not accounted for by the RPA theory
Small scatterers in the lower mantle observed at German broadband arrays
Thomas, C.; Weber, M.; Wicks, C.W.; Scherbaum, F.
1999-01-01
Seismograms of earthquakes from the South Pacific recorded at a German broadband array and network show precursors to PKPdf. These precursors mainly originate from off-path scattering of PKPab or a nearby PKPbc to P (for receiver-side scattering) or from scattering of P to PKPab or PKPbc on the PKPdf path (for source-side scattering). Standard array processing techniques based on plane wave approximations (such as vespagram or frequency-wavenumber analysis) are inadequate for investigating these precursors since scattered waves cannot be approximated as plane waves for arrays and networks larger than 300 x 300 km for short-period waves. We therefore develop a migration method to estimate the location of scatterers in the mantle, at the core-mantle boundary and at the top of the outer core. With our method we are able to find isolated scatterers at the source side and the receiver side, although the depth of the scatterer is not well constrained. However, from looking at the first possible arrival time of precursors at different depth and the region where scattering can take place (scattering volume), we believe that the location of the scatterers is in the lowermost mantle. Since we have detected scatterers in regions where ultralow-velocity zones have been discovered recently, we think that the precursor energy possibly originates from scattering at partial melt at the base of the mantle. Comparing results from broadband and band-pass-filtered data the detection of small-scale structure of the ultralow-velocity zones becomes possible. Copyright 1999 by the American Geophysical Union.
Project study of a small-angle neutron scattering apparatus
International Nuclear Information System (INIS)
Schedler, E.; Pollet, J.L.
1979-03-01
This design study deals with the set up of a low angle scattering apparatus in the HMI reactor hall in Berlin. The experiences of other institutes with facilities of a similar type, - especially with D11 and D17 of the ILL in Grenoble, the set up the KFA in Juelich and of the PTB in Braunschweig -, are included to a large extend. The aim of this paper is - to define the necessary boundary conditions for the construction (including: installation of a cold source, the beam line, the neutron guide pipe and an extention of the reactor hall), -to determine the properties of the planned apparatus, especially in comparison with D11, probably the most versatile instrument, - to make desitions for the design of the components, - to work out the detailed drawings for construction - to estimate the costs and the time necessary for construction, if industrial manufacturers set up the project. (orig.) [de
Practical guide to the PLUTO small angle scattering spectrometer
International Nuclear Information System (INIS)
Page, D.I.
1980-08-01
A schematic diagram of the S.A.N.S. instrument is given. Neutrons from a thermal source in the PLUTO reactor pass successively through a cooled beryllium filter, a helical velocity selector and a flight tube with collimating apertures into a specimen chamber. Monitor fission chambers allow measurements of the transmission of the selector and the flux of neutrons incident on the specimen. The neutrons emerging in the forward direction from the specimen enter the detector box where the unscattered ones are stopped by a beam stop and the scattered ones impinge on a 2-dimensional detector which measures their spatial distribution. The output from the detector is fed into a PDP 11/10 computer where the data is collected, manipulated and displayed on a visual display unit. Performance data and practical operating procedure are given. (author)
Damping and scattering of electromagnetic waves by small ferrite spheres suspended in an insulator
Englert, Gerald W.
1992-01-01
The intentional degradation of electromagnetic waves by their penetration into a media comprised of somewhat sparsely distributed energy absorbing ferrite spheres suspended in an electrical insulator is investigated. Results are presented in terms of generalized parameters involving wave length and sphere size, sphere resistivity, permeability, and spacing; their influence on dissipation of wave power by eddy currents, magnetic hysteresis, and scattering is shown.
International Nuclear Information System (INIS)
Maltman, K.
1998-01-01
Using the framework of effective chiral Lagrangians, we show that, in order to correctly implement electromagnetism (EM), as generated from the Standard Model, into effective hadronic theories (such as meson-exchange models) it is insufficient to consider only graphs in the low-energy effective theory containing explicit photon lines. The Standard Model requires the presence of contact interactions in the effective theory which are electromagnetic in origin, but which involve no photons in the effective theory. We illustrate the problems which can result from a ''standard'' EM subtraction: i.e., from assuming that removing all contributions in the effective theory generated by graphs with explicit photon lines fully removes EM effects, by considering the case of the s-wave ππ scattering lengths. In this case it is shown that such a subtraction procedure would lead to the incorrect conclusion that the strong interaction isospin-breaking contributions to these quantities were large when, in fact, they are known to vanish at leading order in m d -m u . The leading EM contact corrections for the channels employed in the extraction of the I=0,2 s-wave ππ scattering lengths from experiment are also evaluated. (orig.)
International Nuclear Information System (INIS)
Tornow, W.; Braun, R.T.; Witala, H.
1996-01-01
We review published analyses of the final-state-interaction enhancement observed in proton energy distributions obtained from kinematically incomplete neutron-deuteron breakup experiments. We compare the results derived from these analyses for the neutron-neutron scattering length, a nn with our results based on a rigorous treatment of the three-nucleon Faddeev equations in conjunction with the use of realistic nucleon-nucleon potentials. Our values for a nn deviate outside the quoted uncertainties from the ones obtained in the previous analyses where simplified nucleon-nucleon interaction models were employed. In contrast to the previous determinations, the present results for a nn are in clear disagreement with the values for a nn based on π - -deuteron capture experiments. Unless inconsistencies in the experimental neutron-deuteron breakup data at low energies can be resolved and the influence of possible three-nucleon-force effects can be reliably determined, we recommend that one not resort to the kinematically incomplete neutron-deuteron breakup reaction as a tool for determining a quantity as important for nuclear and particle physics as is the neutron-neutron scattering length a nn . (author)
Perkins, Stephen J; Wright, David W; Zhang, Hailiang; Brookes, Emre H; Chen, Jianhan; Irving, Thomas C; Krueger, Susan; Barlow, David J; Edler, Karen J; Scott, David J; Terrill, Nicholas J; King, Stephen M; Butler, Paul D; Curtis, Joseph E
2016-12-01
The capabilities of current computer simulations provide a unique opportunity to model small-angle scattering (SAS) data at the atomistic level, and to include other structural constraints ranging from molecular and atomistic energetics to crystallography, electron microscopy and NMR. This extends the capabilities of solution scattering and provides deeper insights into the physics and chemistry of the systems studied. Realizing this potential, however, requires integrating the experimental data with a new generation of modelling software. To achieve this, the CCP-SAS collaboration (http://www.ccpsas.org/) is developing open-source, high-throughput and user-friendly software for the atomistic and coarse-grained molecular modelling of scattering data. Robust state-of-the-art molecular simulation engines and molecular dynamics and Monte Carlo force fields provide constraints to the solution structure inferred from the small-angle scattering data, which incorporates the known physical chemistry of the system. The implementation of this software suite involves a tiered approach in which GenApp provides the deployment infrastructure for running applications on both standard and high-performance computing hardware, and SASSIE provides a workflow framework into which modules can be plugged to prepare structures, carry out simulations, calculate theoretical scattering data and compare results with experimental data. GenApp produces the accessible web-based front end termed SASSIE-web , and GenApp and SASSIE also make community SAS codes available. Applications are illustrated by case studies: (i) inter-domain flexibility in two- to six-domain proteins as exemplified by HIV-1 Gag, MASP and ubiquitin; (ii) the hinge conformation in human IgG2 and IgA1 antibodies; (iii) the complex formed between a hexameric protein Hfq and mRNA; and (iv) synthetic 'bottlebrush' polymers.
International Nuclear Information System (INIS)
Liu Li; Mishchenko, Michael I.; Cairns, Brian; Carlson, Barbara E.; Travis, Larry D.
2006-01-01
In this study, we model single-scattering properties of small cirrus crystals using mixtures of polydisperse, randomly oriented spheroids and cylinders with varying aspect ratios and with a refractive index representative of water ice at a wavelength of 1.88 μm. The Stokes scattering matrix elements averaged over wide shape distributions of spheroids and cylinders are compared with those computed for polydisperse surface-equivalent spheres. The shape-averaged phase function for a mixture of oblate and prolate spheroids is smooth, featureless, and nearly flat at side-scattering angles and closely resembles those typically measured for cirrus. Compared with the ensemble-averaged phase function for spheroids, that for a shape distribution of cylinders shows a relatively deeper minimum at side-scattering angles. This may indicate that light scattering from realistic cirrus crystals can be better represented by a shape mixture of ice spheroids. Interestingly, the single-scattering properties of shape-averaged oblate and prolate cylinders are very similar to those of compact cylinders with a diameter-to-length ratio of unity. The differences in the optical cross sections, single-scattering albedo, and asymmetry parameter between the spherical and the nonspherical particles studied appear to be relatively small. This may suggest that for a given optical thickness, the influence of particle shape on the radiative forcing caused by a cloud composed of small ice crystals can be negligible
International Nuclear Information System (INIS)
Enik, T.L.; Mitsyna, L.V.; Nikolenko, V.G.; Oprea, I.A.; Parzhitsky, S.S.; Popov, A.B.; Samosvat, G.S.; Vtiuryn, V.A.
1999-01-01
Relationship between the n,e scattering length, b ne , the neutron mean square charge radius n 2 > and anomalous magnetic moment μ n , the quantities which characterize the internal structure of the neutron, was investigated. The performed analysis showed that in the framework of the modern cloudy bag model (CBM) of the nucleon the values of b ne is determined by the value of n 2 > without the so-called Foldy term being taken into account, while in the framework of the phenomenological Foldy approach the experimental values of ne > obtained up to date can be described only by this Foldy term within an accuracy of about 10%, i.e. by the anomalous magnetic moment of the neutron, μ n . Then a necessity is obvious to obtain b ne with higher accuracy than in previous experiments. To remove the contradictions in the experimental b ne estimates, new experiments to measure the energy dependence of the slow neutron scattering cross section by 86 Kr and scattering anisotropy on Xe isotopes, have been proposed. The investigation has been performed at Frank Laboratory of Neutron Physics, JINR. (authors)
The small length scale effect for a non-local cantilever beam: a paradox solved.
Challamel, N; Wang, C M
2008-08-27
Non-local continuum mechanics allows one to account for the small length scale effect that becomes significant when dealing with microstructures or nanostructures. This paper presents some simplified non-local elastic beam models, for the bending analyses of small scale rods. Integral-type or gradient non-local models abandon the classical assumption of locality, and admit that stress depends not only on the strain value at that point but also on the strain values of all points on the body. There is a paradox still unresolved at this stage: some bending solutions of integral-based non-local elastic beams have been found to be identical to the classical (local) solution, i.e. the small scale effect is not present at all. One example is the Euler-Bernoulli cantilever nanobeam model with a point load which has application in microelectromechanical systems and nanoelectromechanical systems as an actuator. In this paper, it will be shown that this paradox may be overcome with a gradient elastic model as well as an integral non-local elastic model that is based on combining the local and the non-local curvatures in the constitutive elastic relation. The latter model comprises the classical gradient model and Eringen's integral model, and its application produces small length scale terms in the non-local elastic cantilever beam solution.
Small angle neutron scattering study of two nonionic surfactants in ...
Indian Academy of Sciences (India)
nonionic surfactants in water micellar solutions. RAJEWSKA ALDONA. Institute of ... water solution for concentration c = 0.17% (dilute regime) at different temperatures in the range t = 10–35°C by small .... which yields the pair distance distribution function p(r), where r is the distance in real space. The point, at which the p(r) ...
International Nuclear Information System (INIS)
Mason, Thomas G.; Lin, Min Y.
2003-01-01
We use time-resolved-small angle neutron scattering to study the kinetics of asphaltene nanoparticle aggregation in incompatible crude oil mixtures. We induce asphaltene aggregation by mixing asphaltene-rich Syrian crude oil (SACO) with a paraffinic British crude oil and observe the scattered neutron intensity, I, as a function of wave number, q, over times, t, ranging from twenty minutes to about a week. We observe a growth in I at low q as the nanoscale asphaltenes agglomerate into microscale aggregates and interpret this growth as an increase in surface scattering from the aggregates. We fit I(q,t) to an empirical model and measure the growth in the power-law exponent, α, associated with the low-q logarithmic slope of I(q). We define a time, τ α , associated with the first appearance of the aggregates when α>3; τ α increases as a function of the volume fraction, φ m , of SACO in the mixture. The surface scattering intensity initially increases and then saturates at long times when the aggregate structures no longer evolve at the length scales we probe. Based on this saturation, we define a time scale, τ I , which is larger than τ α but has essentially the same dependence on φ m . We interpret τ α (φ m ) and τ I (φ m ) in terms of a simple aggregation model based on diffusion-limited kinetics and a repulsive potential barrier that models the effective solvent quality
Elucidation of spin echo small angle neutron scattering correlation functions through model studies.
Shew, Chwen-Yang; Chen, Wei-Ren
2012-02-14
Several single-modal Debye correlation functions to approximate part of the overall Debey correlation function of liquids are closely examined for elucidating their behavior in the corresponding spin echo small angle neutron scattering (SESANS) correlation functions. We find that the maximum length scale of a Debye correlation function is identical to that of its SESANS correlation function. For discrete Debye correlation functions, the peak of SESANS correlation function emerges at their first discrete point, whereas for continuous Debye correlation functions with greater width, the peak position shifts to a greater value. In both cases, the intensity and shape of the peak of the SESANS correlation function are determined by the width of the Debye correlation functions. Furthermore, we mimic the intramolecular and intermolecular Debye correlation functions of liquids composed of interacting particles based on a simple model to elucidate their competition in the SESANS correlation function. Our calculations show that the first local minimum of a SESANS correlation function can be negative and positive. By adjusting the spatial distribution of the intermolecular Debye function in the model, the calculated SESANS spectra exhibit the profile consistent with that of hard-sphere and sticky-hard-sphere liquids predicted by more sophisticated liquid state theory and computer simulation. © 2012 American Institute of Physics
Study on porosity of ceramic SiC using small angle neutron scattering
International Nuclear Information System (INIS)
Li Jizhou; Yang Jilian; Kang Jian; Ye Chuntang
1996-01-01
The mechanical properties of functional heat-resistant ceramics SiC are significantly influenced by the concentration and dimensions of pores. Small angle neutron scattering measurements for 3 SiC samples with different densities are performed on C1-2 SANS instrument of the University of Tokyo. Two groups of the neutron data are obtained using 8 and 16 m of secondary flight path, 1 and 0.7 nm of neutron wave lengths, respectively. After deduction of background measurement and transmission correction, both neutron data are linked up with each other. The patterns of neutron data of 3 samples with Q range from 0.028∼0.5 nm -1 are almost with axial symmetry, showing that the shape of pores is almost spherical. Using Mellin transform, size distributions of pores in 3 samples are obtained. The average size (∼19 nm) of pores for hot-pressed SiC sample with higher density is smaller than the others (∼ 21 nm). It seems to be the reason why the density of hot-pressed SiC sample is higher than not hot-pressed sample
Collagen Orientation and Crystallite Size in Human Dentin: A Small Angle X-ray Scattering Study
Energy Technology Data Exchange (ETDEWEB)
Pople, John A
2001-03-29
The mechanical properties of dentin are largely determined by the intertubular dentin matrix, which is a complex composite of type I collagen fibers and a carbonate-rich apatite mineral phase. The authors perform a small angle x-ray scattering (SAXS) study on fully mineralized human dentin to quantify this fiber/mineral composite architecture from the nanoscopic through continuum length scales. The SAXS results were consistent with nucleation and growth of the apatite phase within periodic gaps in the collagen fibers. These mineralized fibers were perpendicular to the dentinal tubules and parallel with the mineralization growth front. Within the plane of the mineralization front, the mineralized collagen fibers were isotropic near the pulp, but became mildly anisotropic in the mid-dentin. Analysis of the data also indicated that near the pulp the mineral crystallites were approximately needle-like, and progressed to a more plate-like shape near the dentino-enamel junction. The thickness of these crystallites, {approx} 5 nm, did not vary significantly with position in the tooth. These results were considered within the context of dentinogenesis and maturation.
Energy Technology Data Exchange (ETDEWEB)
Petrenko, V. I., E-mail: vip@nf.jinr.ru; Avdeev, M. V. [Joint Institute for Nuclear Research (Russian Federation); Bulavin, L. A. [Taras Shevchenko National University of Kyiv (Ukraine); Almasy, L. [Hungarian Academy of Science, Wigner Research Centre for Physics (Hungary); Grigoryeva, N. A. [St. Petersburg State University (Russian Federation); Aksenov, V. L. [National Research Centre “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)
2016-01-15
The structures of ferrofluids (FFs) based on nonpolar solvent decahydronaphthalene, stabilized by saturated monocarboxylic acids with hydrocarbon chains of different lengths, C16 (palmitic acid) and ?12 (lauric acid), with an excess of acid molecules, have been studied by small-angle neutron scattering. It is found that the addition of acid to an initially stable system with optimal composition leads to more significant structural changes (related to aggregation) than those observed previously for this class of FFs. A comparison of the influence of monocarboxylic acids on the stability of nonpolar FFs suggests that the enhancement of aggregation is much more pronounced in the case of palmitic acid excess. This fact confirms the conclusion of previous studies, according to which an increase in the hydrocarbon chain length in a saturated acid reduces the efficiency of the corresponding FF stabilization.
Small-angle x-ray scattering from the early growth stages of zeolite A
International Nuclear Information System (INIS)
Singh, P.; White, J.
1999-01-01
Full text: The work presented here with the use of SAXS (Small-Angle X-ray Scattering) is in attempt to identify a different paradigm to the organic template induced crystallization of zeolites, in particular zeolite 'A'. The reactions have been followed by small angle X-ray scattering from the time of first mixing of the constituents until the final separation of zeolite A crystals. The processes happening during the growth are expected to follow successive transformation of intermediate metastable phases until the formation of thermodynamically most stable phase and scattering signatures from these developments may be useful for extracting interesting information about the processes in situ. The scattering functions from a synthesis system of zeolite 'A' at the initial and final stage of reaction are presented.The different growth processes of zeolite 'A' from different silicate and aluminium sources are found. The differences are attributed to different rate limiting steps in the syntheses
DEFF Research Database (Denmark)
Arslanagic, Samel
2007-01-01
aspects associated with DNG materials, and was subsequently extended to investigations of the radiation and scattering from two- and three-dimensional (2D and 3D) MTM-based canonical problems in electromagnetic theory. As to the theoretical aspects of DNG materials, the sign, or more generally the branch......, cylindrical and spherical configurations to design electrically small, resonant structures such as cavities, waveguides, scatterers and radiators. These ideas are extended here to canonical antenna and scattering configurations which consist of electrically small resonant cylindrical and spherical MTM......-based structures excited by an arbitrarily located electric line source and an arbitrarily located and oriented electric Hertzian dipole, respectively. Exact analytical solutions, based on eigenfunction series, are derived and then numerically evaluated to study the radiation and scattering from these structures...
Varghese, Babu; Rajan, Vinayakrishnan; van Leeuwen, Ton G.; Steenbergen, Wiendelt
2007-01-01
In optical Doppler measurements, the path length of the light is unknown. To facilitate quantitative measurements, we develop a phase-modulated Mach-Zehnder interferometer with separate fibers for illumination and detection. With this setup, path-length-resolved dynamic light scattering measurements
Detection of structural defects in lecithin membranes by the small-angle neutron scattering method
International Nuclear Information System (INIS)
Bezzabotnov, V.Yu.; Gordelij, V.I.; Ostanevich, Yu.M.; Yaguzhinskij, L.S.
1989-01-01
Irregularities interpreted as interdomain defects have been detected in model lipid membranes of dipalmitoil lecithin in liquid L α -phase by the method of small-angle scattering (lateral diffraction). The dimensions and concentrations of the defects were about those supposed within the dynamic cluster model of bilayer (Ivkov, 1984). No irregularities were detected in the solid Lβ ' -phase (the diffusion scattering intensity was at least ten times less)
International Nuclear Information System (INIS)
Lychagin, E.V.; Muzychka, A.Yu.; Nekhaev, G.V.; Strelkov, A.V.; Shvetsov, V.N.; Nesvizhevskij, V.V.; Tal'daev, R.R.
2001-01-01
Inelastic scattering of neutrons with small energy transfer of ∼10 -7 eV was investigated using gravitational UCN spectrometer. The probability of such a process at stainless steel and beryllium surfaces was measured. It was also estimated at copper surface. The measurement showed that the detected flux of neutrons scattered at beryllium and copper surfaces is ∼ 2 times higher at room temperature compared to that at the liquid nitrogen temperature. (author)
Moussaid , A.; Schosseler , F.; Munch , J.; Candau , S.
1993-01-01
The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiemnts. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to t...
A small angle neutron scattering study of mica based glass-ceramics with applications in dentistry
International Nuclear Information System (INIS)
Kilcoyne, S.H.; Bentley, P.M.; Al-Jawad, M.; Bubb, N.L.; Al-Shammary, H.A.O.; Wood, D.J.
2004-01-01
We are currently developing machinable and load-bearing mica-based glass-ceramics for use in restorative dental surgery. In this paper we present the results of an ambient temperature small angle neutron scattering (SANS) study of several such ceramics with chemical compositions chosen to optimise machinability and strength. The SANS spectra are all dominated by scattering from the crystalline-amorphous phase interface and exhibit Q -4 dependence (Porod scattering) indicating that, on a 100 A scale, the surface of the crystals is smooth
Small-angle and surface scattering from porous and fractal materials.
Energy Technology Data Exchange (ETDEWEB)
Sinha, S. K.
1998-09-18
We review the basic theoretical methods used to treat small-angle scattering from porous materials, treated as general two-phase systems, and also the basic experimental techniques for carrying out such experiments. We discuss the special forms of the scattering when the materials exhibit mass or surface fractal behavior, and review the results of recent experiments on several types of porous media and also SANS experiments probing the phase behavior of binary fluid mixtures or polymer solutions confined in porous materials. Finally, we discuss the analogous technique of off-specular scattering from surfaces and interfaces which is used to study surface roughness of various kinds.
Small angle neutron scattering (SANS) study of gastric mucin solutions
Hong, Z.; Bansil, R.; Waigh, T.; Turner, B.; Bhaskar, K. R.; Afdhal, N.; Lal, J.
2002-03-01
We report the first results from a SANS study of purified porcine gastric mucin solutions in D2O. The ability of this glycoprotein to protect the stomach epithelium from acid damage, may be due to a pH dependent conformational transition which leads to gelation at low pH Cao et. al. (Biophysical. J. 76, 1250, 1999). SANS measurements were made over the concentration range of 1 -15 mg/ml at pH 7, 4 and 2. The data indicate that at pH 7 the excluded volume exponent is 1.7, characteristic of swollen chains whereas at pH 2 this exponent increases to 2, indicating theta or poor solvent conditions, consistent with the hydrophobic interactions increasing at lower pH. From a Guinier analysis of the 1mg/ml data at low q's (0.003- 0.007 Å-1) we estimate the cross section radius of the effective cylinder to be 23nm and its length as 96nm in an unbuffered sample, i.e. close to pH 7. In the intermediate q-range (0.01 -0.1Å-1) at pH 7 a fit to the Debye chain gives radius of gyration Rg of 16nm. Mucin is best modelled as an elongated micelle with a cylindrical or worm-like chain to represent the protein core and the sugar chains forming the corona. Results of such calculations will be presented.
A review on the study of polymer properties by Small Angle Neutron Scattering
International Nuclear Information System (INIS)
Seong, Baek Seok; Lee, Chang Hee; Sim, Hae Seop; Lee, Jung Sool; Kim, Hong Doo; Kim, Eu Gene; Cha, Kuk Heon
1998-05-01
This report contains concept of small angle neutron scattering , various design features and considerations of the small angle neutron spectrometer at HANARO, and recent trends of polymer studies by using this SANS technique with the installation of the spectrometer in near future. We, therefore, wish to review feasibility of small angle studies for polymer field at this spectrometer and to help possible beam time users for their experimental consideration. (author). 23 refs., 7 tabs., 23 figs
International Nuclear Information System (INIS)
Korneta, W.; Lopez Quintela, M.A.; Liz, L.
1993-09-01
The experimental results obtained by the static small-angle neutron scattering technique for the microemulsion consisting of 40% in volume of nonionic surfactant pentaethylene-glycol-4-octylphenylether, equal volumes of heavy water and decane, and additives (the salt KCl, the anionic surfactant SDS and butanol) are presented and discussed. The universal features of obtained scattering intensity plots are determined. The shape of the peak present in all scattering spectra was fitted by the universal function derived from the density functional theory. The persistence length of surfactant sheet used in many density functional theories of microemulsions is determined and the effect of different additives on this length is shown. (author). 10 refs, 2 figs
A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering
Energy Technology Data Exchange (ETDEWEB)
Round, A R [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Wilkinson, S J [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Hall, C J [Daresbury Laboratories, Warrington, WA4 4AD (United Kingdom); Rogers, K D [Department of Materials and Medical Sciences, Cranfield University, Swindon, SN6 8LA (United Kingdom); Glatter, O [Department of Chemistry, University of Graz (Austria); Wess, T [School of Optometry and Vision Sciences, Cardiff University, Cardiff CF10 3NB, Wales (United Kingdom); Ellis, I O [Nottingham City Hospital, Nottingham (United Kingdom)
2005-09-07
Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique.
A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering
International Nuclear Information System (INIS)
Round, A R; Wilkinson, S J; Hall, C J; Rogers, K D; Glatter, O; Wess, T; Ellis, I O
2005-01-01
Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique
A preliminary study of breast cancer diagnosis using laboratory based small angle x-ray scattering
Round, A. R.; Wilkinson, S. J.; Hall, C. J.; Rogers, K. D.; Glatter, O.; Wess, T.; Ellis, I. O.
2005-09-01
Breast tissue collected from tumour samples and normal tissue from bi-lateral mastectomy procedures were examined using small angle x-ray scattering. Previous work has indicated that breast tissue disease diagnosis could be performed using small angle x-ray scattering (SAXS) from a synchrotron radiation source. The technique would be more useful to health services if it could be made to work using a conventional x-ray source. Consistent and reliable differences in x-ray scatter distributions were observed between samples from normal and tumour tissue samples using the laboratory based 'SAXSess' system. Albeit from a small number of samples, a sensitivity of 100% was obtained. This result encourages us to pursue the implementation of SAXS as a laboratory based diagnosis technique.
Frey, S; Weysser, F; Meyer, H; Farago, J; Fuchs, M; Baschnagel, J
2015-02-01
We present molecular-dynamics simulations for a fully flexible model of polymer melts with different chain length N ranging from short oligomers (N = 4) to values near the entanglement length (N = 64). For these systems we explore the structural relaxation of the supercooled melt near the critical temperature T c of mode-coupling theory (MCT). Coherent and incoherent scattering functions are analyzed in terms of the idealized MCT. For temperatures T > T c we provide evidence for the space-time factorization property of the β relaxation and for the time-temperature superposition principle (TTSP) of the α relaxation, and we also discuss deviations from these predictions for T ≈ T c. For T larger than the smallest temperature where the TTSP holds we perform a quantitative analysis of the dynamics with the asymptotic MCT predictions for the late β regime. Within MCT a key quantity, in addition to T c, is the exponent parameter λ. For the fully flexible polymer models studied we find that λ is independent of N and has a value (λ = 0.735 ) typical of simple glass-forming liquids. On the other hand, the critical temperature increases with chain length toward an asymptotic value T c (∞) . This increase can be described by T c (∞) - T c(N) ∼ 1/N and may be interpreted in terms of the N dependence of the monomer density ρ, if we assume that the MCT glass transition is ruled by a soft-sphere-like constant coupling parameter Γ c = ρ c T c (-1/4), where ρ c is the monomer density at T c. In addition, we also estimate T c from a Hansen-Verlet-like criterion and MCT calculations based on structural input from the simulation. For our polymer model both the Hansen-Verlet criterion and the MCT calculations suggest T c to decrease with increasing chain length, in contrast to the direct analysis of the simulation data.
International Nuclear Information System (INIS)
Witala, H.; Hueber, D.; Gloeckle, W.; Tornow, W.; Gonzalez Trotter, D.E.
1996-01-01
Data for the neutron-neutron final-state-interaction cross section obtained recently in a kinematically complete neutron-deuteron breakup experiment have been reanalyzed using rigorous solutions of the three-nucleon Faddeev equations with realistic nucleon-nucleon interactions. A discrepancy was found with respect to a recent analysis based on the W-matrix approximation to the Paris potential. We also estimate theoretical uncertainties in extracting the neutron-neutron scattering length resulting from the use of different nucleon-nucleon interactions and the possible action of the two pion-exchange three-nucleon force. We find that there exists a certain production angle for the interacting neutron-neutron pair where the uncertainties become minimal. (author)
Shimizu, S; Furusaka, M
2002-01-01
Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D sub 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D sub 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)
International Nuclear Information System (INIS)
Shimizu, S.; Kurita, K.; Furusaka, M.
2002-01-01
Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)
International Nuclear Information System (INIS)
Braun, A.; Kohlbrecher, J.; Baertsch, M.; Schnyder, B.; Koetz, R.; Haas, O.; Wokaun, A.
2004-01-01
The electrochemical double layer capacitance and internal surface area of a pyrolytic carbon material after electrochemical oxidation and subsequent reduction was studied with cyclic voltammetry and small-angle neutron scattering. Oxidation yields an enhanced internal surface area (activation), and subsequent reduction causes a decrease of this internal surface area. The change of the Porod constant, as obtained from small-angle neutron scattering, reveals that the decrease in internal surface area is not caused merely by a closing or narrowing of the pores, but by a partial collapse of the pore network
Evaluation of solution stability for two-component polydisperse systems by small-angle scattering
Kryukova, A. E.; Konarev, P. V.; Volkov, V. V.
2017-12-01
The article is devoted to the modelling of small-angle scattering data using the program MIXTURE designed for the study of polydisperse multicomponent mixtures. In this work we present the results of solution stability studies for theoretical small-angle scattering data sets from two-component models. It was demonstrated that the addition of the noise to the data influences the stability range of the restored structural parameters. The recommendations for the optimal minimization schemes that permit to restore the volume size distributions for polydisperse systems are suggested.
Structure of fullerene aggregates in pyridine/water solutions by small-angle neutron scattering
International Nuclear Information System (INIS)
Aksenov, V.L.; Belushkin, A.V.; Avdeev, M.V.; Rosta, L.; Mihailovic, D.; Mrzel, A.; Serdyuk, I.N.; Timchenko, A.A.
2001-01-01
Results of small-angle neutron scattering experiments on fullerenes (C 60 ) in pyridine/water solutions are reported. They confirm conclusions of the previous studies, in particular, dynamic light scattering experiments. Aggregates with characteristic radius of about 20 nm are formed in the solutions. The contrast variation using different combinations of protonated/deuterated components (water and pyridine) of the solutions points to the small pyridine content inside the aggregates. This fact testifies that the aggregates consist of a massive fullerene core covered by a thin pyridine shell
Small angle neutron scattering studies of the flux line lattices in the borocarbide superconductors
Energy Technology Data Exchange (ETDEWEB)
Eskildsen, Morten Ring
1998-12-01
This thesis describes small angle neutron scattering studies of the flux line lattice (FLL) in the following members of the borocarbide superconductors: YNi{sub 2}B{sub 2}C, ErNi{sub 2}B{sub 2}C, TmNi{sub 2}B{sub 2}C, LuNi{sub 2}B{sub 2}C, Y{sub 0.75}Lu{sub 0.25}Ni{sub 2}B{sub 2}C and Lu(Ni{sub 1-x}CO{sub x}){sub 2}B{sub 2}C with x = 1.5 - 9%. Of the materials ErN{sub 2}B{sub 2}C and TmNi{sub 2}B{sub 2}C exhibits coexisting superconductivity and magnetic ordering. Three main conclusions can be derived from the results in this thesis. Existence of a low field hexagonal to square symmetry transition of the FLL, ubiquitous to the superconducting borocarbides, magnetic and non-magnetic alike. This symmetry transition is due to the four-fold anisotropy of the Fermi surface, distorting the screening currents towards a square flow pattern. This four-fold anisotropy together with non-local electrodynamics induces a transition to a square FLL, as the field is increased. Changing the non-locality range shifts the square to hexagonal transition onset field. A static disordering of the FLL in YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C. In these materials one observes a well ordered FLL, with a longitudinal correlation length exceeding 100 flux line spacings. As the applied field is increased the longitudinal correlation length, increases with field up to H/H{sub c2} {approx} 0.2. Above this field the FLL correlation length slowly starts to fall off, in contradiction to theoretical models. The existence of complex interactions between the magnetic state and the FLL in TmNi{sub 2}B{sub 2}C. This is signalled by coinciding changes in the FLL symmetry and in the magnetic structure. The FLL show a two-step symmetry transition from square to rhombic and then hexagonal with increased field. In addition, the FLL reflectivity shows distinct peaks as the thulium ions orders magnetically at T{sub N} and across the field driven magnetic transition. No explanation for this behaviour
Small angle neutron scattering studies of the flux line lattices in the borocarbide superconductors
International Nuclear Information System (INIS)
Eskildsen, Morten Ring
1998-12-01
This thesis describes small angle neutron scattering studies of the flux line lattice (FLL) in the following members of the borocarbide superconductors: YNi 2 B 2 C, ErNi 2 B 2 C, TmNi 2 B 2 C, LuNi 2 B 2 C, Y 0.75 Lu 0.25 Ni 2 B 2 C and Lu(Ni 1-x CO x ) 2 B 2 C with x = 1.5 - 9%. Of the materials ErN 2 B 2 C and TmNi 2 B 2 C exhibits coexisting superconductivity and magnetic ordering. Three main conclusions can be derived from the results in this thesis. Existence of a low field hexagonal to square symmetry transition of the FLL, ubiquitous to the superconducting borocarbides, magnetic and non-magnetic alike. This symmetry transition is due to the four-fold anisotropy of the Fermi surface, distorting the screening currents towards a square flow pattern. This four-fold anisotropy together with non-local electrodynamics induces a transition to a square FLL, as the field is increased. Changing the non-locality range shifts the square to hexagonal transition onset field. A static disordering of the FLL in YNi 2 B 2 C and LuNi 2 B 2 C. In these materials one observes a well ordered FLL, with a longitudinal correlation length exceeding 100 flux line spacings. As the applied field is increased the longitudinal correlation length, increases with field up to H/H c2 ∼ 0.2. Above this field the FLL correlation length slowly starts to fall off, in contradiction to theoretical models. The existence of complex interactions between the magnetic state and the FLL in TmNi 2 B 2 C. This is signalled by coinciding changes in the FLL symmetry and in the magnetic structure. The FLL show a two-step symmetry transition from square to rhombic and then hexagonal with increased field. In addition, the FLL reflectivity shows distinct peaks as the thulium ions orders magnetically at T N and across the field driven magnetic transition. No explanation for this behaviour exists at the present. (au)
X-ray small-angle scattering of polytetrahydrofuran solution, 3
International Nuclear Information System (INIS)
Izumi, Yoshinobu; Fuji, Masayuki; Shinbo, Kazuyuki; Miyake, Yasuhiro
1975-01-01
In a previous report, the conformation of polytetrahydrofuran (PTHF) in isopropyl alcohol as a theta solvent and in n-butyl alcohol as an intermediate solvent was examined by the small angle scattering of X-ray. As the result, the experimental scattering curve at theta temperature was explained well with the calculated curve obtained by superposing, while it was impossible to apply the similar method to the analysis of the scattering curve in the intermediate solvent. Recently, as the results of the calculation by Koyama on the angular distribution of light intensity scattered by stiff chain polymers and of the studies by Edwards and de Gennes on the asymptotic behavior of scattering curves in good solvents, the direct comparison of experimental and calculated scattering curves became possible. In this report, the comparison of the scattering curves of PTHF-alcohol systems is described. The systems employed were PTHF-n-propyl alcohol, PTHF-isobutyl alcohol, PTHF-sec-butyl alcohol, and PTHF-tert-butyl alcohol in addition to the previous two systems. The Guinier plots of the cross section factors of the PTHF-alcohol systems showed that the Guinier approximation on cross sections was not satisfied in cases of PTHF-isobutyl alcohol and PTHF-sec-butyl alcohol. The light scattering data at 44.6 0 C, the theta temperature of PTHF-isopropyl alcohol, are given. From the figures comparing experimental and calculated scattering curves, it was shown that there was appreciable solvent effect on the scattering curves of PTHF-alcohol systems. The relation predicted by Edwards and de Gennes was satisfied well in case of the systems in good solvents. (Kako, I.)
Small angle neutron scattering modeling of copper-rich precipitates in steel
International Nuclear Information System (INIS)
Spooner, S.
1997-11-01
The magnetic to nuclear scattering intensity ratio observed in the scattering from copper rich precipitates in irradiated pressure vessel steels is much smaller than the value of 11.4 expected for a pure copper precipitate in iron. A model for precipitates in pressure vessel steels which matches the observed scattering typically incorporates manganese, nickel, silicon and other elements and it is assumed that the precipitate is non-magnetic. In the present work consideration is given to the effect of composition gradients and ferromagnetic penetration into the precipitate on the small angle scattering cross section for copper rich clusters as distinguished from conventional precipitates. The calculation is an extension of a scattering model for micelles which consist of shells of varying scattering density. A discrepancy between recent SANS scattering experiments on pressure vessel steels was found to be related to applied magnetic field strength. The assumption of cluster structure and its relation to atom probe FIM findings as well as the effects of insufficient field for magnetic saturation is discussed
Rakotonarivo, S T; Walker, S C; Kuperman, W A; Roux, P
2011-12-01
A method to actively localize a small perturbation in a multiple scattering medium using a collection of remote acoustic sensors is presented. The approach requires only minimal modeling and no knowledge of the scatterer distribution and properties of the scattering medium and the perturbation. The medium is ensonified before and after a perturbation is introduced. The coherent difference between the measured signals then reveals all field components that have interacted with the perturbation. A simple single scatter filter (that ignores the presence of the medium scatterers) is matched to the earliest change of the coherent difference to localize the perturbation. Using a multi-source/receiver laboratory setup in air, the technique has been successfully tested with experimental data at frequencies varying from 30 to 60 kHz (wavelength ranging from 0.5 to 1 cm) for cm-scale scatterers in a scattering medium with a size two to five times bigger than its transport mean free path. © 2011 Acoustical Society of America
International Nuclear Information System (INIS)
Arum Patriati; Edy Giri Rachman Putra
2009-01-01
The effect of different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH 3 (CH 2 ) 10 COOH and hexadecanoic acid, CH 3 (CH 2 ) 14 COOH as a co-surfactant in the 0.3M SDS micellar solution has been studied using small angle neutron scattering (SANS). Here, the present of dodecanoic acid has induced the SDS structural micelles. The ellipsoid micelles structures changed significantly in length (major axis) from 21.7 Armstrong to 35.5 Armstrong at a fixed minor axis of 16.7 Armstrong in the present of 0.005M to 0.1M dodecanoic acid. Nevertheless, this effect was not shown in the present of hexadecanoic acid with the same concentration range. The present of hexadecanoic acid molecules gave a small effect on growth of SDS micelles where the major axis of the micelle was simply elongated from 21.5 Armstrong to 23.5 Armstrong. It showed that the appropriate hydrocarbon chain length between surfactant and co-surfactant molecules is one of the determining factors in forming a mixed micelles structure. (author)
Phase separation process in FeCr alloys studied by neutron small angle scattering
International Nuclear Information System (INIS)
Furusaka, Michihiro; Ishikawa, Yoshikazu; Yamaguchi, Sadae; Fujino, Yutaka.
1986-01-01
The very early stage as well as late stage of phase separation process in FeCr alloys (Fe-20, 30, 40, 60 at%Cr) have been studied by pulsed cold neutron small angle scattering instrument (SAN). At the early stage, scattering intensity I(q) obeys q -2 dependence at the high q side of the scattering function. The results are in accord with the theory of Langer et al. which takes into account nonlinear and thermal fluctuations effects. At the late stage where I(q) shows q -4 dependence, a dynamical scaling law holds, while it is not the case for the earlier stage. Phase diagram of FeCr system is also determined by critical scattering measurements. (author)
Observations of short period seismic scattered waves by small seismic arrays
Directory of Open Access Journals (Sweden)
M. Simini
1997-06-01
Full Text Available The most recent observations of well correlated seismic phases in the high frequency coda of local earthquakes recorded throughout the world are reported. In particular the main results, obtained on two active volcanoes, Teide and Deception, using small array are described. The ZLC (Zero Lag Cross-correlation method and polarization analysis have been applied to the data in order to distinguish the main phases in the recorded seismograms and their azimuths and apparent velocities. The results obtained at the Teide volcano demonstrate that the uncorrelated part of the seismograms may be produced by multiple scattering from randomly distributed heterogeneity, while the well correlated part, showing SH type polarization or the possible presence of Rayleigh surface waves, may be generated by single scattering by strong scatterers. At the Deception Volcano strong scattering, strongly focused in a precise direction, is deduced from the data. In that case, all the coda radiation is composed of surface waves.
Marliere, C; Etienne, P; Woignier, T; Dieudonné, P; Phalippou, J
2001-01-01
During the last few years the bulk structure of silica aerogels has been extensively studied mainly by scattering techniques (neutrons, X-rays, light). It has been shown that small silica particles aggregate to constitute a fractal network. Its spatial extension and fractal dimension are strongly dependent on the synthesis conditions (e.g., pH of gelifying solutions). These typical lengths range from 1 to 10 nm. Ultra-small angle X-ray scattering (USAXS) and atomic force microscopy (AFM) experiments have been carried out on aerogels at different steps of densification. The results presented in this paper reveal the existence of a spatial arrangement of the solid part at a very large length scale. The evolution of this very large-scale structure during the densification process has been studied and reveals a contraction of this macro-structure made of aggregates of clusters. (16 refs).
International Nuclear Information System (INIS)
Bulyiginskiy, D.G.; Gurchenko, A.D.; Gusakov, E.Z.; Korkin, V.V.; Larionov, M.M.; Novik, K.M.; Petrov, Yu.V.; Popov, A.Yu.; Saveliev, A.N.; Selenin, V.L.; Stepanov, A.Yu.
2001-01-01
The upper hybrid resonance (UHR) scattering technique possessing such merits as one-dimensional probing geometry, enhancement of cross section, and fine localization of scattering region is modified in the new diagnostics under development to achieve wave number resolution. The fluctuation wave number is estimated in the new technique from the scattering signal time delay measurements. The feasibility of the scheme is checked in the proof of principal experiment in a tokamak. The time delay of the UHR scattering signal exceeding 10 ns is observed. The small scale low frequency density fluctuations are investigated in the UHR RADAR backscattering experiment. The UHR cross-polarization scattering signal related to small scale magnetic fluctuations is observed. The lower hybrid (LH) wave propagation and both linear and nonlinear wave conversion are investigated. The small wavelength (λ≤0.02 cm) high number ion Bernstein harmonics, resulting from the linear wave conversion of the LH wave are observed in a tokamak plasma for the first time
Small-angle x-ray scattering in amorphous silicon: A computational study
Paudel, Durga; Atta-Fynn, Raymond; Drabold, David A.; Elliott, Stephen R.; Biswas, Parthapratim
2018-05-01
We present a computational study of small-angle x-ray scattering (SAXS) in amorphous silicon (a -Si) with particular emphasis on the morphology and microstructure of voids. The relationship between the scattering intensity in SAXS and the three-dimensional structure of nanoscale inhomogeneities or voids is addressed by generating large high-quality a -Si networks with 0.1%-0.3% volume concentration of voids, as observed in experiments using SAXS and positron annihilation spectroscopy. A systematic study of the variation of the scattering intensity in the small-angle scattering region with the size, shape, number density, and the spatial distribution of the voids in the networks is presented. Our results suggest that the scattering intensity in the small-angle region is particularly sensitive to the size and the total volume fraction of the voids, but the effect of the geometry or shape of the voids is less pronounced in the intensity profiles. A comparison of the average size of the voids obtained from the simulated values of the intensity, using the Guinier approximation and Kratky plots, with that of the same from the spatial distribution of the atoms in the vicinity of void surfaces is presented.
International Nuclear Information System (INIS)
Kiselev, M.A.; Aksenov, V.L.; Lombardo, D.; Kisselev, A.M.; Lesieur, P.
2003-01-01
Small-angle X-ray scattering (SAXS) experiments have been performed on dimyristoylphosphatidylcholine (DMPC) unilamellar vesicles in 40% aqueous sucrose solution. Model of separated form factors was applied for the evaluation of SAXS curves from large unilamellar vesicles. For the first time vesicle structure factor, polydispersity, average radius and membrane thickness were calculated simultaneously from the SAXS curves at T=30 deg C for DMPC concentrations in the range from 15 to 75 mM (1-5% w/w). Structure factor correction to the scattering curve was shown to be negligibly small for the lipid concentration of 15 mM (1% w/w). It was proved to be necessary to introduce structure factor correction to the scattering curves for lipid concentrations ≥ 30 mM (2% w/w)
International Nuclear Information System (INIS)
Kwiecinski, J.
1994-05-01
The basic QCD expectations concerning the deep inelastic scattering at low x where x is the Bjorken scaling variable are reviewed. This includes discussion of the BFKL equation which sums the leading powers of ln (1/x) and the shadowing effects. Phenomenological implications of the theoretical expectations for the deep inelastic lepton-hadron scattering in the small x region which has become accessible at the HERA ep collider are described. We give predictions for structure functions F 2 which are based on the BFKL equation and the high energy k T factorization theorem. These predictions are compared with the results of structure function analysis based on Altarelli-Parisi evolution equations and confronted with the recent data from HERA. We discuss jet production and transverse energy flow in deep inelastic lepton scattering as the measurements which may be particularly suitable for revealing the QCD dynamics at small x. (author). 37 refs, 4 figs
Particle and particle systems characterization small-angle scattering (SAS) applications
Gille, Wilfried
2016-01-01
Small-angle scattering (SAS) is the premier technique for the characterization of disordered nanoscale particle ensembles. SAS is produced by the particle as a whole and does not depend in any way on the internal crystal structure of the particle. Since the first applications of X-ray scattering in the 1930s, SAS has developed into a standard method in the field of materials science. SAS is a non-destructive method and can be directly applied for solid and liquid samples. Particle and Particle Systems Characterization: Small-Angle Scattering (SAS) Applications is geared to any scientist who might want to apply SAS to study tightly packed particle ensembles using elements of stochastic geometry. After completing the book, the reader should be able to demonstrate detailed knowledge of the application of SAS for the characterization of physical and chemical materials.
Kiselev, M A; Kisselev, A M; Lesieur, P; Aksenov, V L
2003-01-01
Small-angle X-ray scattering (SAXS) experiments have been performed on dimyristoylphosphatidylcholine (DMPC) unilamellar vesicles in 40 % aqueous sucrose solution. Model of separated form factors was applied for the evaluation of SAXS curves from large unilamellar vesicles. For the first time vesicle structure factor, polydispersity, average radius and membrane thickness were calculated simultaneously from the SAXS curves at T=306{\\circ}C for DMPC concentrations in the range from 15 to 75 mM (1-5 % w/w). Structure factor correction to the scattering curve was shown to be negligibly small for the lipid concentration of 15 mM (1 % w/w). It was proved to be necessary to introduce structure factor correction to the scattering curves for lipid concentrations {\\ge}30 mM (2 % w/w).
Mehta, Rujul
2005-03-01
Molecular composites, composed of uniformly dispersed rigid-rod liquid crystalline polymer (LCP) molecules in a flexible amorphous polymer matrix, have remained hitherto elusive due to a scarcity of miscible systems containing a LCP and an amorphous polymer. The production of such a blend, with an experimentally accessible miscibility window, has become possible by modifying the architecture of the flexible polymer, so as to induce favorable intermolecular hydrogen bonding. Specifically, liquid crystalline polyurethanes (LCPU) are found to be miscible with a copolymer of styrene and vinyl phenol; with optimum hydrogen bonding between the carbonyl groups of the urethane linkages and the hydroxyl groups present in the styrenic matrix. Availability of a truly miscible molecular composite presents a unique opportunity of studying the confirmation of polymer chains containing rigid-rods that are uniformly dispersed in a flexible coil matrix. A system consisting of the LCPU and the deuterated styrenic copolymer containing 20% vinyl phenol is examined by Small Angle Neutron Scattering at the National Center for Neutron Research at Gaithersburg and Technology, and the Institute of Solid State Research (IFF) at Jülich. Scattering curves for neat dPS-VPh did not fit the Debye-Bueche model; indicating complex structure. A two correlation length Debye-Bueche model was considered to accommodate for this nonlinear behavior. This model utilizes four fitting parameters, including two correlation lengths a1 and a2, corresponding to a Debye-Bueche model and Guinier model.
International Nuclear Information System (INIS)
Garcia, J.P.; Manso, M.E.; Serra, F.M.; Mendonca, J.T.
1989-01-01
When a wave propagates in a non homogeneous fluctuating plasma part of the incident energy is scattered out to the nonlinear interaction between the wave and the oscillating modes perturbing the plasma. The possibility of enhanced scattering at the cutoff layer, where reflection of the incident wave occurs, has been recently suggested as the basis of a reflectometric experiment to determine the spatial location of small scale fluctuations in a fusion plasma. Here we report on the development of a theoretical model to evaluate the flux of energy scattered by fluctuations, in order to give insight about the interpretation of measurements using a microwave reflectometry diagnostic in a tokamak. The scattered field is obtained through the resolution of a (non-homogeneous) wave propagation equation where the source term is related with the nonlinear current due to the interaction between the incident wave and local fluctuations. We use a slab model for the plasma, and an ordinary (0) wave propagation along the density gradient is considered. The amplitude of the scattered wave at the border of the plasma is estimated. In order to know the contributions to the energy scattered both from the propagation region and the reflecting layer, an approach was used where perturbations are modelled by spatial step functions at several layers. The main contribution to the scattered power comes from the cutoff region, where the electric field amplitude swells as compared with the incident value. Considering the reflectometric system recently installed on the ASDEX tokamak, and using typical density profiles, expected values of the 'swelling factor' have been numerically evaluated. The role of incoherent scattering due to drift wave activity is discussed as well as the coherent scattering due to fluctuations induced by lower hybrid (LH) waves. (author) 2 refs., 4 figs
Rübe, Andrea; Hause, Gerd; Mäder, Karsten; Kohlbrecher, Joachim
2005-10-03
The contrast variation technique in small angle neutron scattering (SANS) was used to investigate the inner structure of nanocapsules on the example of poly(D,L-lactide) (PLA) nanocapsules. The determination of the PLA and Poloxamer shell thickness was the focus of this study. Highest sensitivity on the inner structure of the nanocapsules was obtained when the scattering length density of the solvent was varied between the one of the Miglyol core and the PLA shell. According to the fit data the PLA shell thickness was 9.8 nm. The z-averaged radius determined by SANS experiments correlated well with dynamic light scattering (DLS) results, although DLS values were systematically slightly higher than the ones measured by SANS. This could be explained by taking into account the influence of Poloxamer attached to the nanocapsules surface. For a refined fit model with a second shell consisting of Poloxamer, SANS values and DLS values fitted well with each other. The characterization method presented here is significant because detailed insights into the nanocapsule and the Poloxamer shell were gained for the first time. This method could be used to develop strategies for the optimization of the shell properties concerning controlled release and to study changes in the shell structure during degradation processes.
International Nuclear Information System (INIS)
Yee Madeira, H.T.
1989-03-01
The scope of this work is the investigation of the system PV ME/d-PS by small angle neutron scattering (SANS). The measurements were done with a pinhole-camera and a high resolution double crystal diffractometer and covered the resolution range from 10 -3 to 3x10 -2 A -1 and 2x10 -5 to 6x10 -4 A -1 respectively. As a basis for these investigations the phase diagram of a PVME/d-PS mixture was measured with SANS. The spinodal for different curve between stable and demixing region was obtained. For PVME with molecular weights M ω =60000 and d-PS with M ω =215103 the critical point is at the concentration Φ=0.2. From the spinodal and the structure factor the Flory-Huggins parameter Χ could be extracted as a function of temperature. It was found that Χ=0 for T comp =135 0 C and Χ is independent of the molecular weight within the accuracy of the data, thus Χ may be associated with a local interaction parameter. The scattering experiments for the determination of the spinodal confirmed the mean-field behaviour of the critical scattering which was earlier found by Herkt-Maetzky and Schelten. Further, the time dependence of the structure factor in the miscibility gap was investigated. From the structure factors, specially from the position Q max of their maxima, a characteristic length was extracted. (orig./RB) [de
International Nuclear Information System (INIS)
Kiselev, M.A.; Zemlyanaya, E.V.; Aswal, V.K.; Neubert, R.H.H.
2005-01-01
Small angle neutron scattering (SANS) on the unilamellar vesicle populations (diameter of 500 and 1000 Armstrong) was used to characterize lipid vesicles from dimyristoylphosphatidylcholine (DMPC) in three phases (gel, ripple, and liquid). Parameters of vesicle populations and internal structure of the DMPC bilayer were characterized on the basis of the Separated Form Factor (SFF) model. Vesicle shape changes from about spherical in liquid phase to elliptical in ripple and gel phases for vesicles prepared via extrusion through pores with the diameter of 500 Armstrong. Parameters of the internal bilayer structure (membrane thickness, thickness of the hydrophobic core, hydration, and surface area of lipid molecule) were determined on the basis of the Hydrophobic-Hydrophilic (HH) approximation of neutron scattering length density across the bilayer ρ(x) and on the basis of the Step Function (SF) approximation of ρ(x). It was demonstrated in the framework of HH approximation that DMPC membrane thickness in the liquid phase (T = 30 deg C) depends on the membrane curvature. Vesicle population prepared via extrusion through pores with the diameter of 500 Armstrong is characterized by an average radius of 275.6 ± 0.5 Armstrong, polydispersity of 27%, membrane thickness of 47.8 ± 0.2 Armstrong, thickness of hydrophobic core of 20.5 ± 0.3 Armstrong, surface area per DMPC molecule of 61.0 ± 0.4 A 2 Armstrong, and the number of water molecules per DMPC molecule of 11.9 ± 0.3. Vesicles prepared via extrusion through pores with the diameter of 1000 Armstrong have a polydispersity of 48%, and a membrane thickness of 45.6 ± 0.2 Armstrong. SF approximation was used to describe the DMPC membrane structure in gel (T 10 deg C) and ripple (T = 20 deg C) phases. DMPC vesicles prepared via extrusion through 1000- Armstrong pores have a membrane thickness of 49.6 ± 0.5 Armstrong in the gel phase and 48.3 ± 0.6 Armstrong in the ripple phase. The dependence of the DMPC membrane
Time-resolved small-angle neutron scattering study on soap-free emulsion polymerization
Energy Technology Data Exchange (ETDEWEB)
Motokawa, Ryuhei [Research Group of Soft Matter and Neutron Scattering, Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan); Koizumi, Satoshi [Research Group of Soft Matter and Neutron Scattering, Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan)]. E-mail: koizumi@neutrons.tokai.jaeri.go.jp; Hashimoto, Takeji [Research Group of Soft Matter and Neutron Scattering, Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan); Nakahira, Takayuki [Department of Applied Chemistry and Biotechnology, Chiba University, Chiba-shi, Chiba 263-8522 (Japan); Annaka, Masahiko [Department of Chemistry, Kyushu University, Fukuoka 812-8581 (Japan)
2006-11-15
We investigated an aqueous soap-free emulsion polymerization process of Poly(N-isopropylacrylamide)-block-poly(ethylene glycol) by ultra-small-angle and time-resolved small-angle neutron scattering methods. The results indicate that the compartmentalization of chain end radicals into solid-like micelle cores crucially leads to the quasi-living behavior of the radical polymerization by prohibiting recombination process.
International Nuclear Information System (INIS)
Schmidt, P.W.; Tang, Y.; Roell, A.; Steiner, M.; Hoehr, A.; Neumann, H.B.
1990-01-01
Small-angle x-ray and neutron scattering are useful methods for investigating the structure of materials on a scale from about 10 to 2000 A. Some experimental procedures and methods of data analysis for small-angle scattering are outlined, and the use of small-angle scattering for studies of polydisperse systems (i.e., systems of particles of different size) of independently scattering particles is reviewed. Some general properties of the small-angle scattering from mass and surface fractals are discussed, and some applications of these concepts in recent experimental studies are presented. Results obtained in calculations of the small-angle scattering from a model of a surface are summarized. (author) 3 figs., 18 refs
Analysis of small-angle scattering data from micelles and microemulsions
DEFF Research Database (Denmark)
Pedersen, J.S.
1999-01-01
The free-form methods for analyzing small-angle scattering data have, during the last years, found more widespread use for micelles and microemulsions. Recent developments have made them applicable also to systems with size polydispersity and particle correlations, however, model fitting still...
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.)
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.)
Data Analysis Of Small Angle X-Ray Solution Scattering And Its ...
African Journals Online (AJOL)
Small Angle X-ray Scattering analysis was used for the study of the protein, Human Tumour Necrosis Factor (TNF) homogeneously dispersed in solution. The experiment consisted in sending a well collimated beam of synchrotron radiation of wavelength, λ through the sample and measuring the variation of the intensity as a ...
Small angle neutron scattering analysis programs on the Rutherford Laboratory IBM 360/195 computers
International Nuclear Information System (INIS)
Knowles, K.J.; Johnson, M.W.
1980-06-01
The implementation and operation of the suite of programs used for the analysis of small angle neutron scattering data originally written at the ILL (Grenoble) is described. The programs make use of a circulating data file which is also described and may be used by a variety of data analysis programs. (author)
DEFF Research Database (Denmark)
Nagy, Gergely; Posselt, Dorthe; Kovacs, Laszlo
2011-01-01
In the present study, we determined characteristic repeat distances of the photosynthetic membranes in living cyanobacterial and eukaryotic algal cells, and in intact thylakoid membranes isolated from higher plants with time-resolved small-angle neutron scattering. This non-invasive technique...
Investigation of nanoscale structures by small-angle X-ray scattering in a radiochromic dosimeter
DEFF Research Database (Denmark)
Skyt, Peter Sandegaard; Jensen, Grethe Vestergaard; Wahlstedt, Isak Hannes
2014-01-01
This study examines the nanoscale structures in a radiochromic dosimeter that was based on leuco-malachite-green dye and the surfactant sodium dodecyl sulfate (SDS) suspended in a gelatin matrix. Small-angle X-ray scattering was used to investigate the structures of a range of compositions...
The analysis of nano structures based on small angle scattering of neutrons
International Nuclear Information System (INIS)
Len, Adel; Fuzi, Janos; Rosta, Laszlo; Harmat, Peter
2014-01-01
The paper describes the technology of small angle neutron scattering from neutron beam cooling to beam focusing and image processing. The applicability of the method is illustrated by sodium bubble analysis in tungsten, and investigation of the the effect of microbial transglutamase on casein micellas.
Simulated small-angle scattering patterns for a plastically deformed model composite material
Shenoy, V.B.; Cleveringa, H.H.M.; Phillips, R.; Giessen, E. van der; Needleman, A.
2000-01-01
The small-angle scattering patterns predicted by discrete dislocation plasticity versus local and non-local continuum plasticity theory are compared in a model problem. The problem considered is a two-dimensional model composite with elastic reinforcements in a crystalline matrix subject to
Proceedings of the workshop on small angle scattering data analysis. Micelle related topics
Energy Technology Data Exchange (ETDEWEB)
Yamaguchi, Toshio [Fukuoka Univ. (Japan). Faculty of Science; Furusaka, Michihiro; Ohtomo, Toshiya [eds.
1996-02-01
This workshop was held on December 13 and 14, 1995 at National Laboratory for High Energy Physics. At the workshop, the purpose of the workshop was explained, and lectures were given on the research on superhigh molecular structure by small angle neutron scattering, the verification of the reliability of WINK data (absolute intensity), the analysis of WINK data, the new data program of SAN, small angle X-ray scattering data analysis program (SAXS), the basis of the analysis of micelle system, analysis software manual and practice program Q-I(Q) ver 1.0, various analysis methods for small angle scattering and contrast modulation method and others, the ordering of and the countermeasures to the problems of WINK, and the hereafter of KENS small angle scattering facility. How to treat the analysis related to micelle, how to save WINK and how to install the SAN/reflectometer are the matters to be discussed at the workshop. In this book, the summaries of the lectures are collected. (K.I.)
Informing the improvement of forest products durability using small angle neutron scattering
Nayomi Plaza Rodriguez; Sai Venkatesh Pingali; Shuo Qian; William T. Heller; Joseph E. Jakes
2016-01-01
A better understanding of how wood nanostructure swells with moisture is needed to accelerate the development of forest products with enhanced moisture durability. Despite its suitability to study nanostructures, small angle neutron scattering (SANS) remains an underutilized tool in forest products research. Nanoscale moisture-induced structural changes in intact and...
Structure of unilamellar vesicles: Numerical analysis based on small-angle neutron scattering data
International Nuclear Information System (INIS)
Zemlyanaya, E. V.; Kiselev, M. A.; Zbytovska, J.; Almasy, L.; Aswal, V. K.; Strunz, P.; Wartewig, S.; Neubert, R.
2006-01-01
The structure of polydispersed populations of unilamellar vesicles is studied by small-angle neutron scattering for three types of lipid systems, namely, single-, two-and four-component vesicular systems. Results of the numerical analysis based on the separated-form-factor model are reported
A small-angle scattering study of bacteriophage T7 using synchrotron radiation
International Nuclear Information System (INIS)
Feigin, L.A.; Svergun, D.I.; Dembo, A.T.; Ronto, G.; Toth, K.
1989-01-01
Structure transitions in the bacterial virus T7, due to an environment of varying ionic strength, are investigated by means of synchrotron radiation small-angle scattering. Effects of radiation damages and kinetics of the structure transition are separated. Time dependencies of the structural parameters and distribution functions are obtained and characteristic features of the structure rearrangements are described. (orig.)
Small-angle X-ray scattering documents the growth of metal-organic frameworks
Goesten, M.G.; Stavitski, I.; Juan-Alcañiz, J.; Martinez-Joaristi, A.; Petukhov, A.V.; Kapteijn, F.; Gascon, J.
2013-01-01
We present a combined in situ small- and wide-angle scattering (SAXS/WAXS) study on the crystallization of two topical metal-organic frameworks synthesized from similar metal and organic precursors: NH2-MIL-53(Al) and NH2-MIL-101(Al). A thorough analysis of SAXS data reveals the most important
On the study of the transfer ionization reactions at super small scattering angles
International Nuclear Information System (INIS)
Popov, Yu.V.; Chuluunbaatar, O.; Vinitskij, S.I.; Ancarani, L.U.; Dal Cappello, C.; Vinitskij, P.S.
2002-01-01
The hypothesis that the reaction p + He → H + He ++ + e at super small scattering angles of hydrogen can be used for purposes of the angular spectroscopy of electron-electron correlations in the target is considered. It is shown that this hypothesis is untenable
On the Study of the Transfer Ionization Reactions at Super Small Scattering Angles
Popov, Yu V; Vinitsky, S I; Ancarani, L U; Dal Cappello, C; Vinitsky, P S
2002-01-01
The hypothesis that the reaction p + He\\to H + He^{++} + e at super small scattering angles of hydrogen can be used for purposes of the angular spectroscopy of electron-electron correlations in the target is considered. It is shown that this hypothesis is insolvent.
Investigation of metallic and ceramic materials by small-angle neutron scattering
Smirnov, YI; Elyutin, NO
Small-angle neutron scattering measurements on a double-crystal spectrometer with perfect monochromator and analyzer crystals were used to follow microstructural changes in the aluminum alloy VD-17. refractory alloy ZhS-6, and dispersion-hardened zirconia-based ceramics with yttria additions. The
Small-angle neutron scattering at pulsed sources compared to reactor sources
International Nuclear Information System (INIS)
Hjelm, R.P. Jr.; Seeger, P.A.; Thiyagarajan, P.
1990-01-01
Detailed comparisons of measurements made on small-angle neutron scattering instruments at pulsed spallation and reactor sources show that the results from the two types of instruments are comparable. It is further demonstrated that spallation instruments are preferable for measurements in the mid-momentum transfer domain or when a large domain is needed. 8 refs., 2 figs
V4: The Small Angle Scattering Instrument (SANS at BER II
Directory of Open Access Journals (Sweden)
Uwe Keiderling
2016-11-01
Full Text Available V4 is a small-angle neutron scatting instrument with an accessible range of scattering vector 0.01 nm-1 < Q < 8.5 nm-1. Outstanding features of the instrument are the polarized neutron option and the list mode data acquisition, allowing for time-resolved measurements with µs time resolution.
Bacteriophage T7 structure according to the data of small-angle X-ray scattering
Energy Technology Data Exchange (ETDEWEB)
Rol' bin, Yu A; Svergun, D I; Feigin, L A; Gashpar, Sh; Ronto, D [AN SSSR, Moscow. Inst. Kristallografii
1980-01-01
An attempt is made to obtain complete data on the form, sizes, weight and hydration of the T7 bacteriophage cultivated on E.coli cells and the peculiarities of phage DNA structure using the method of small-angle scattering.
Czech Academy of Sciences Publication Activity Database
Woo, W.; Em, V.; Shin, E.; Mikula, Pavol; Ryukhtin, Vasyl
2015-01-01
Roč. 48, APR (2015), s. 350-356 ISSN 0021-8898 R&D Projects: GA ČR GB14-36566G; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : peak broadening * small-angle neutron scattering * neutron diffraction * magnetic domain Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.720, year: 2014
International Nuclear Information System (INIS)
Kremer, J. P.; Pedersen, T. Sunn; Lefrancois, R. G.; Marksteiner, Q.
2006-01-01
The creation of the first small-Debye length, low temperature pure electron plasmas in a stellarator is reported. A confinement time of 20 ms has been measured. The long confinement time implies the existence of macroscopically stable equilibria and that the single particle orbits are well confined despite the lack of quasisymmetry in the device, the Columbia non-neutral torus. This confirms the beneficial confinement effects of strong electric fields and the resulting rapid ExB rotation of the electrons. The particle confinement time is presently limited by the presence of bulk insulating materials in the plasma, rather than any intrinsic plasma transport processes. A nearly flat temperature profile is seen in the inner part of the plasma
Kremer, J P; Pedersen, T Sunn; Lefrancois, R G; Marksteiner, Q
2006-09-01
The creation of the first small-Debye length, low temperature pure electron plasmas in a stellarator is reported. A confinement time of 20 ms has been measured. The long confinement time implies the existence of macroscopically stable equilibria and that the single particle orbits are well confined despite the lack of quasisymmetry in the device, the Columbia non-neutral torus. This confirms the beneficial confinement effects of strong electric fields and the resulting rapid E x B rotation of the electrons. The particle confinement time is presently limited by the presence of bulk insulating materials in the plasma, rather than any intrinsic plasma transport processes. A nearly flat temperature profile is seen in the inner part of the plasma.
Gritsevich, M.; Penttilä, A.; Maconi, G.; Kassamakov, I.; Martikainen, J.; Markkanen, J.; Vaisanen, T.; Helander, P.; Puranen, T.; Salmi, A.; Hæggström, E.; Muinonen, K.
2017-12-01
Electromagnetic scattering is a fundamental physical process that allows inferring characteristics of an object studied remotely. This possibility is enhanced by obtaining the light-scattering response at multiple wavelengths and viewing geometries, i.e., by considering a wider range of the phase angle (the angle between the incident light and the light reflected from the object) in the experiment. Within the ERC Advanced Grant project SAEMPL (http://cordis.europa.eu/project/rcn/107666_en.html) we have assembled an interdisciplinary group of scientists to develop a fully automated, 3D scatterometer that can measure scattered light at different wavelengths from small particulate samples. The setup comprises: (a) the PXI Express platform to synchronously record data from several photomultiplier tubes (PMTs); (b) a motorized rotation stage to precisely control the azimuthal angle of the PMTs around 360°; and (c) a versatile light source, whose wavelength, polarization, intensity, and beam shape can be precisely controlled. An acoustic levitator is used to hold the sample without touching it. The device is the first of its kind, since it measures controlled spectral angular scattering including all polarization effects, for an arbitrary object in the µm-cm size scale. It permits a nondestructive, disturbance-free measurement with control of the orientation and location of the scattering object. To demonstrate our approach we performed detailed measurements of light scattered by a Chelyabinsk LL5 chondrite particle, derived from the light-colored lithology sample of the meteorite. These measurements are cross-validated against the modeled light-scattering characteristics of the sample, i.e., the intensity and the degree of linear polarization of the reflected light, calculated with state-of-the-art electromagnetic techniques (see Muinonen et al., this meeting). We demonstrate a unique non-destructive approach to derive the optical properties of small grain samples
International Nuclear Information System (INIS)
Han, Young-Soo; Jang, Jin-Sung; Mao, Xiaodong
2015-01-01
Ferritic ODS(Oxide-dispersion-strengthened) alloy is known as a primary candidate material of the cladding tubes of a sodium fast reactor (SFR) in the Generation IV research program. In ODS alloy, the major contribution to the enhanced high-temperature mechanical property comes from the existence of nano-sized oxide precipitates, which act as obstacles to the movement of dislocations. In addition for the extremely high temperature application(>950 .deg. C) of future nuclear system, Ni base ODS alloys are considered as candidate materials. Therefore the characterization of nano-sized microstructures is important for determining the mechanical properties of the material. Small angle neutron scattering (SANS) technique non-destructively probes structures in materials at the nano-meter length of scale (1 - 1000 nm) and has been a very powerful tool in a variety of scientific/engineering research areas. In this study, nano-sized microstructures were quantitatively analyzed by small angle neutron scattering. Quantitative microstructural information on nanosized oxide in ODS alloys was obtained from SANS data. The effects of the thermo mechanical treatment on the size and volume fraction of nano-sized oxides were analyzed. For 12Cr ODS alloy, the experimental A-ratio is two-times larger than the theoretical A-ratio., and this result is considered to be due to the imperfections included in YTaO 4 . For Ni base ODS alloy, the volume fraction of the mid-sized particles (- 30 nm) increases rapidly as hot extrusion temperature decreases
Improved performances of 36 m small-angle neutron scattering spectrometer BATAN in Serpong Indonesia
International Nuclear Information System (INIS)
Putra, Edy Giri Rachman; Bharoto; Santoso, Eddy; Ikram, Abarrul
2009-01-01
SMARTer, a 36 m small-angle neutron scattering (SANS) spectrometer owned by the National Nuclear Energy Agency of Indonesia (BATAN) was installed at the Neutron Scattering Laboratory (NSL) in Serpong, Indonesia. Lots of works on replacing, upgrading and improving the control system, experimental methods, data collection and reduction in the last two years have been carried out to optimize the performance of SMARTer. Some standard samples such as silver behenate, monodisperse polystyrene nanoparticle, porous silica and block copolymer PS-PEP film were measured for the inter-laboratory comparison.
Density model for medium range order in amorphous materials: application to small angle scattering
International Nuclear Information System (INIS)
Boucher, B.; Tournarie, M.; Chieux, P.; Convert, P.
1983-06-01
We consider a family of randomly spaced parallel planes, each plane dressed with a density function, h(x), where x is the distance from the plane. An expression for the volume scattering power from a system of N such families with random orientations in space is derived from Fourier transform of h(x), which can subsequently be determined from experimental observations. This density model is used to interpret the small angle neutron scattering (SANS) results for the amorphous alloy TbCusub(3.54)
International Nuclear Information System (INIS)
Chew, H.; McNulty, P.J.
1982-01-01
In earlier work a model of fluorescent and Raman scattering by active molecules represented as classical electric dipoles embedded in small particles was developed. The intensity and angular distribution of the inelastically scattered radiation was shown to depend on the geometric and optical properties of the particle. The model was originally developed for particles having spherical shape and later extended to concentric spheres, cylinders, and prolate spheroids. The active molecules were originally assumed to be isotropically polarizable. The model has been recently extended to certain types of anisotropically polarizable molecules. The model had also been applied to particles having internal structure
Fractal morphology in lignite coal: a small angle x-ray scattering investigation
International Nuclear Information System (INIS)
Chitra, R.; Sen, D.; Mazumder, S.; Chandrasekaran, K.S.
1999-01-01
Small angle x-ray scattering technique has been used to study the pore morphology in lignite coal from Neyveli lignite mine (Tamilnadu, India). The sample were collected from three different locations of the same mine. SAXS profiles from all the three samples show almost identical functionality, irrespective of the locations from where the samples were collected. SAXS experiment using two different wavelengths also exhibit same functionality indicating the absence of multiple scattering. The analysis indicates the surface fractal nature of the pore morphology. The surface fractal dimension is calculated to be 2.58. (author)
Energy Technology Data Exchange (ETDEWEB)
Moussaid, A. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Schosseler, F. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Munch, J.P. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Candau, S.J. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France))
1993-04-01
The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiments. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to the experimental data. For a narrow range of ionization degrees nearly quantitative agreement with the theory is found for the polyacrylic acid system. (orig.).
Moussaid, A.; Schosseler, F.; Munch, J. P.; Candau, S. J.
1993-04-01
The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiemnts. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to the experimental data. For a narrow range of ionizaiton degrees nearly quantitative agreement with the theory is found for the polyacrylic acide system.
The Small-Angle Neutron Scattering Data Analysis of the Phospholipid Transport Nanosystem Structure
Zemlyanaya, E. V.; Kiselev, M. A.; Zhabitskaya, E. I.; Aksenov, V. L.; Ipatova, O. M.; Ivankov, O. I.
2018-05-01
The small-angle neutron scattering technique (SANS) is employed for investigation of structure of the phospholipid transport nanosystem (PTNS) elaborated in the V.N.Orekhovich Institute of Biomedical Chemistry (Moscow, Russia). The SANS spectra have been measured at the YuMO small-angle spectrometer of IBR-2 reactor (Joint Institute of Nuclear Research, Dubna, Russia). Basic characteristics of polydispersed population of PTNS unilamellar vesicles (average radius of vesicles, polydispersity, thickness of membrane, etc.) have been determined in three cases of the PTNS concentrations in D2O: 5%, 10%, and 25%. Numerical analysis is based on the separated form factors method (SFF). The results are discussed in comparison with the results of analysis of the small-angle X-ray scattering spectra collected at the Kurchatov Synchrotron Radiation Source of the National Research Center “Kurchatov Institute” (Moscow, Russia).
International Nuclear Information System (INIS)
Shukla, A.; Kiselev, M.A.; Hoell, A.; Neubert, R.H.H.
2004-01-01
Microemulsions (MEs) are of special interest because a variety of reactants can be introduced into the nanometer-sized aqueous domains, leading to materials with controlled size and shape. In the past few years, significant research has been conducted in the reverse ME-mediated synthesis of organic nanoparticles. In this study, a w/o ME medium was employed for the synthesis of lidocaine by direct precipitation in w/o microemulsion systems: water/isopropylpalmitat/Tween80/Span80. The particle size as well as the location of nanoparticles in the ME droplet were characterized by means of dynamic light scattering (DLS) and small angle neutron scattering (SANS). It is observed that lidocaine precipitated in the aqueous cores because of its insolubility in water. Hydrodynamic radius and gyration radius of microemulsion droplets were estimated as ∼15 nm and ∼4.50 nm from DLS and SANS respectively. Furthermore, different size parameters obtained by DLS and SANS experiments were compared. (author)
Shukla, A.; Kiselev, M. A.; Hoell, A.; Neubert, R. H. H.
2004-08-01
Microemulsions (MEs) are of special interest because a variety of Reactants can be introduced into the nanometer-sized aqueous domains, leading to materials with controlled size and shape [1,2]. In the past few years, significant research has been conducted in the reverse ME-mediated synthesis of organic nanoparticles [3,4]. In this study, a w/o ME medium was employed for the synthesis of lidocaine by direct precipitation in w/o microemulsion systems: water/isopropylpalmitat/Tween80/Span80. The particle size as well as the location of nanoparticles in the ME droplet were characterized by means of dynamic light scattering (DLS) and small angle neutron scattering (SANS). It is observed that lidocaine precipitated in the aqueous cores because of its insolubility in water. Hydrodynamic radius and gyration radius of microemulsion droplets were estimated as ~15 nm and ~4.50 nm from DLS and SANS respectively. Furthermore, different size parameters obtained by DLS and SANS experiments were compared
Polymer boosting effect in the droplet phase studied by small-angle neutron scattering
Frielinghaus, H; Allgaier, J; Richter, D; Jakobs, B; Sottmann, T; Strey, R
2002-01-01
Small-angle neutron-scattering experiments were performed in order to obtain the six partial scattering functions of a droplet microemulsion containing water, decane, C sub 1 sub 0 E sub 4 surfactant and PEP sub 5 -PEO sub 8 sub 0. We systematically varied the contrast around the polymer contrast, where only the polymer becomes visible, and we also measured bulk and film contrasts. With the singular value decomposition method we could extract the desired six partial scattering functions from the 15 measured spectra. We find a sphere-shell-shell structure of the droplets, where the innermost sphere consists of oil, the middle shell of surfactant and the outer shell is a depletion zone where the polymer is almost not present. (orig.)
[Fluorescent and Raman scattering by molecules embedded in small particles]: Annual report, 1983
International Nuclear Information System (INIS)
Chew, H.; McNulty, P.J.
1983-01-01
An overview is given of the model formulated for fluorescent and Raman scattering by molecules embedded in or in the vicinity of small particles. The model takes into account the size, shape, refractive index, and morphology of the host particles. Analytic and numerical results have been obtained for spherical (one and more layers, including magnetic dipole transitions), cylindrical, and spheroidal particles. Particular attention has been given to the spherical case with fluorescent/Raman scatterers uniformly distributed in the particles radiating both coherently and incoherently. Depolarization effects have been studied with suitable averaging process, and good agreement with experiment has been obtained. Analytic and numerical results have been obtained for the elastic scattering of evanescent waves; these results are useful for the study of fluorescence under excitation by evanescent waves
Proteins on surfaces investigated by microbeam grazing incidence small angle X-ray scattering
Energy Technology Data Exchange (ETDEWEB)
Gebhardt, Ronald; Riekel, Christian; Burghammer, Manfred [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex (France); Vendrely, Charlotte [Universite de Cergy-Pontoise, ERRMECE, F-95000, Cergy-Pontoise (France); Mueller-Buschbaum, Peter [TU Muenchen, Physik Department E13, Muenchen (Germany)
2009-07-01
Grazing incidence small angle scattering with a 1 micron x-ray beam ({mu}GISAXS) is applied to study structural ordering of casein micelles and fibroin in solution cast films. {mu}GISAXS scans provide the possibility to locate highly ordered areas and to investigate variation in the molecular packing. In the case of the casein micelles, ordered film structures have been generated by decreasing their natural size dispersion. While dynamic light scattering was used to characterize the different size fractions in solution, {mu}GISAXS and roughness are measured on the resulting casein films. GISAXS-Patterns are analyzed by simulations providing the dimension and nearest neighbor distances of casein micelles. In the case of fibroin, ordering of nano-fibers formed during the drying process is investigated. The experimental data are analyzed by simulations and compared to SEM, AFM and Raman scattering experiments.
Anomalous small-angle x-ray scattering of a femtosecond irradiated germano silicate fibre preform.
Energy Technology Data Exchange (ETDEWEB)
Hindle, F.; Fertein, E.; Seifert, S.; Przygodski, C.S.; Bocquet, R.; Douay, M.; Bychkov, E.; Experimental Facilities Division (APS); LPCA, CNRS; PhLAM; Univ. des Sciences et Tech. de Lille
2005-01-01
RADIATION is shown to induce significant mesoscopic structure. The scattering intensity for irradiated glasses is close to two orders of magnitude greater than that of unexposed material. Anomalous small-angle X-ray scattering (ASAXS) around the germanium K-edge for the silica and germanium doped silica regions of a fiber preform is used to demonstrate that identical structures are induced in both glass materials, with germanium displaying a capacity to isomorphically replace silicon in the case of the germanium doped silica. Analysis of measured scattering indicates that photo-inscribed features are produced at two distinct scales with typical radii of R {approx} 20 Angstroms and R{sub min} {approx} 200 Angstroms.
Interpretation and Utility of the Moments of Small-Angle X-Ray Scattering Distributions.
Modregger, Peter; Kagias, Matias; Irvine, Sarah C; Brönnimann, Rolf; Jefimovs, Konstantins; Endrizzi, Marco; Olivo, Alessandro
2017-06-30
Small angle x-ray scattering has been proven to be a valuable method for accessing structural information below the spatial resolution limit implied by direct imaging. Here, we theoretically derive the relation that links the subpixel differential phase signal provided by the sample to the moments of scattering distributions accessible by refraction sensitive x-ray imaging techniques. As an important special case we explain the scatter or dark-field contrast in terms of the sample's phase signal. Further, we establish that, for binary phase objects, the nth moment scales with the difference of the refractive index decrement to the power of n. Finally, we experimentally demonstrate the utility of the moments by quantitatively determining the particle sizes of a range of powders with a laboratory-based setup.
Small-angle neutron scattering from poly(NIPA-co-AMPS) gels
DEFF Research Database (Denmark)
Travas-Sejdic, J.; Easteal, A.; Knott, R.
2000-01-01
was reversed; that is the lower cross-link density, the higher the scattered intensity. Therefore, the role of cross-links at high temperature was to suppress microphase separation. The fitting of the experimental data with the Rabin and Panyukov theory indicated qualitative agreement.......The microstructure of the poly( N-isopropylacrylamide-co-acrylamido- 2-methyl-1-propane sulphonic acid) gel, poly( NIPA-co-AMPS), was investigated as a function of temperature and cross-link density using the small angle neutron scattering technique. The sample temperature was varied in the range...... 30 to 55C. Two different behaviours of poly( NIPA-co-AMPS) gels were observed. At low temperature (30C), the magnitude of the scattered intensity increased with cross-link density suggesting that additional cross-links introduced more inhomogeneities in the gel network. At high temperatures the trend...
Particle size distribution models of small angle neutron scattering pattern on ferro fluids
International Nuclear Information System (INIS)
Sistin Asri Ani; Darminto; Edy Giri Rachman Putra
2009-01-01
The Fe 3 O 4 ferro fluids samples were synthesized by a co-precipitation method. The investigation of ferro fluids microstructure is known to be one of the most important problems because the presence of aggregates and their internal structure influence greatly the properties of ferro fluids. The size and the size dispersion of particle in ferro fluids were determined assuming a log normal distribution of particle radius. The scattering pattern of the measurement by small angle neutron scattering were fitted by the theoretical scattering function of two limitation models are log normal sphere distribution and fractal aggregate. Two types of particle are detected, which are presumably primary particle of 30 Armstrong in radius and secondary fractal aggregate of 200 Armstrong with polydispersity of 0.47 up to 0.53. (author)
Small-angle X-ray scattering studies of thermally-induced globular protein gels
International Nuclear Information System (INIS)
Clark, A.H.; Tuffnell, C.D.
1980-01-01
Small-angle X-ray scattering has been applied to gels formed by heating globular proteins, in aqueous solution, above their unfolding temperatures. A number of BSA gels, previously characterised by electron microscopy, have been studied, and by setting up theoretical models for the scattering process, the X-ray data have been shown to be consistent with the microscope conclusions regarding network structure. It is concluded that the networks form by a linearly-directed aggregation of unfolded, disc-like, protein molecules, three-dimensional geometry being achieved by occasional branching, and/or cross-linking. Long-range inhomogeneities in network structure, easily observed by electron microscopy, and correlated with variations in pH or ionic strength, have an effect on X-ray scattering, and hence the X-ray method is sensitive not only to different network strand thicknesses, but to different degrees of uniformity as well. (author)
EDITORIAL Proceedings of the XIV International Conference on Small-Angle Scattering, SAS-2009
Ungar, Goran; Heenan, Richard
2010-10-01
Vasilieva and teams from St Petersburg and Moscow describe in paper 012029 a study of a FCC/HCP photonic crystal with a unit cell of 650 nm using the DUBBLE beamline at ESRF, where the incident beam is focused with a compound Berilium lens to give divergence in the microradian range. Defects, correlation lengths, mosaic spread and twinning could be studied in a thin film. The use of grazing incidence small- and intermediate-angle X-ray scattering (GISAXS) was illustrated on several examples of complex liquid crystal phases and nanoparticle systems by Xiangbing Zeng and the team from Sheffield in paper 012032. Apart from the intrinsic interest in the structure of thin films of these materials, the close proximity of the surface imposes usually a very high degree of preferred orientation, facilitating structural analysis. From the papers describing the use of neutron scattering, we highlight the study by Léon van Heijkamp and the Delft group, paper 012016, which describes proof-of-principle experiments using spin-echo SANS (SESANS) for the study of D2O-labeled liposomes and their destruction with a view of providing a nondestructive technique for monitoring targeted drug delivery for the destruction of tumor tissue. This technique is based on monitoring the decay of spin polarization of scattered neutrons, and it can probe correlation lengths from nanometres to tens of microns. In paper 012002 Thomas Zemb discusses the various ways in which SAXS and SANS data can be combined to investigate microemulsions of surfactants lacking long-range order. Thus, for example, it is described how form and structure factors can be separated, or how the degree of connectivity can be determined between rod-like entities forming 'molten cubic' or 'sponge' phases. In the Theory, Data Processing and Modelling section we highlight two papers. Paper 012012, by Carlos Cabrillo and co-workers from Madrid, presents a real-space model for powder samples of relatively highly ordered colloidal
Progresses in the measurement and evaluation of small-angle x-ray scattering data
International Nuclear Information System (INIS)
Bergmann, A.
2000-08-01
Scattering methods are a widely used technique for determining size and shape of particles in the mesoscopic size range. This work deals on the one hand with the development of instruments in the field of Small Angle x-ray Scattering (SAXS) and on the other hand with methodical contributions concerning the interpretation of small angle scattering data. After a short introduction about Small Angle Scattering (SAS) and its application in chapter one, follows in chapter two a derivation of the theory of Small Angle x-ray scattering. Thereafter indirect transformations (Generalized Indirect Fourier Transformation [GIFT], Indirect Fourier Transformation [IFT]) are discussed and in this connection the optimization of multidimensional hyper surfaces is described. There are different possibilities for optimizing such multidimensional surfaces. The pros and contras of the different optimization methods with respect to the evaluation of small angle scattering data from interacting systems are discussed in detail. Global optimization methods are mainly used, if the hypersurface, which has to be optimized, shows many local minima. The goal of the optimization is it to find the global minimum. It is essential, that the parameters of the hyper surface are independent of each other, as it is the case in the GIFT. If someone deals with problems in only few dimensions or with many boundary conditions, mostly local optimization routines are sufficient. Therefore a number of starting parameters for the optimization is chosen, which can be obtained systematically or randomly. The best solution obtained represents the result of the optimization procedure. Chapter 3 deals with the description of instruments used in the field of Small Angle x-ray Scattering. After a description of the components (x-ray sources, monochromators, detectors) of these instruments, the different beam geometries are discussed. In chapter 4 improvements of SAXS measurements on Kratky slit systems by Goebel
Structure of the capsid of Kilham rat virus from small-angle neutron scattering
International Nuclear Information System (INIS)
Wobbe, C.R.; Mitra, S.; Ramakrishnan, V.
1984-01-01
The structure of empty capsids of Kilham rat virus, an autonomous parvovirus with icosahedral symmetry, was investigated by small-angle neutron scattering. From the forward scatter, the molecular weight was determined to be 4.0 x 10(6), and from the Guinier region, the radius of gyration was found to be 105 A in D2O and 104 A in H 2 O. On the basis of the capsid molecular weight and the molecular weights and relative abundances of the capsid proteins, the authors propose that the capsid has a triangulation number of 1. Extended scattering curves and mathematical modeling revealed that the capsid consists of two shells of protein, the inner shell extending from 58 to 91 A in D2O and from 50 to 91 A in H 2 O and containing 11% of the capsid scattering mass, and the outer shell extending to 121 A in H 2 O and D2O. The inner shell appears to have a higher content of basic amino acids than the outer shell, based on its lower scattering density in D2O than in H 2 O. The authors propose that all three capsid proteins contribute to the inner shell and that this basic region serves DNA binding and partial charge neutralization functions
International Nuclear Information System (INIS)
Epperson, J.E.; Lin, J.S.; Spooner, S.
1986-02-01
Small angle neutron scattering (SANS) allows clustering phenomena to be studied in systems for which the constituent atoms do not differ greatly in atomic number. This investigation used SANS to characterize the fine scale microstructure in two cast and aged duplex stainless steels; aging times extended up to eight years. The steels differed in ferrite content by about a factor of two. The scattering at lowest q was dominated by magnetic scattering effects associated with the ferrite phase. In the range 0.025 less than or equal to q less than or equal to 0.2A -1 , additional scattering due to a precipitating phase rich in Ni and Si was observed. This scattering was rather intense and revealed a volume fraction of precipitate, in the ferrite, estimated to be 12 to 18% after long time aging. After about 70,000 hours at 400 0 C, there were about 10 18 precipitate particles per cm 3 some 50A in mean diameter, and they were distributed in a nonrandom manner, i.e., spatially, short-range-ordered. This investigation suggests that after aging some 70,000 hours at 400 0 C, the precipitate in the ferrite phase is undergoing Ostwald ripening. The present data are insufficient to indicate at what time this ripening process began
International Nuclear Information System (INIS)
Broome, J.
1965-11-01
The programme SCATTER is a KDF9 programme in the Egtran dialect of Fortran to generate normalized angular distributions for elastically scattered neutrons from data input as the coefficients of a Legendre polynomial series, or from differential cross-section data. Also, differential cross-section data may be analysed to produce Legendre polynomial coefficients. Output on cards punched in the format of the U.K. A. E. A. Nuclear Data Library is optional. (author)
Small-Angle Neutron Scattering investigations of ferrofluids with different carrier liquids
International Nuclear Information System (INIS)
Balasoiu, M.; Avdeev, M. V.; Hasegan, D.; Ghenescu, V.; Ghenescu, M.; Bica, D.; Vekas, L.
2004-01-01
The aim of this paper is to present a method to investigate the properties of magnetic fluids by means of small angle neutron scattering (SANS). Ferrofluids are dispersions of small, single-domain magnetic particles suspended in a fluid carrier. The neutron scattering methods have been largely used the last two decades for the determination of structural properties of magnetic liquids at microscopic level. There can be investigated the structure of the particle, the aggregation phenomena, the magnetic liquid dynamics, particle-surfactant interaction, surfactant liquid-base interaction and structure and magnetic behavior of the samples. SANS is often used in structural studies of ferrofluids exploring two specific features of neutrons, the possibility of wide contrast variation using protonated/deuterated components and high magnetic scattering from ferromagnetics. This method can be effectively used for determination of the structural parameters of ferrofluids at the scale interval of 1-100 nm. In previous SANS experiments with ferrofluids of the same type it was shown that the nuclear scattering is described well by the spherical core-shell model (magnetite core plus surfactant shell) in a wide interval of momentum transfer (0.05 - 5 nm -1 ) and no significant effects of aggregation and interparticle interaction were observed in this interval for the magnetite concentration up to 5 vol. %. Experiments on small angle neutron scattering were carried out on SANS instrument YuMO in function at IBR-2 high pulsed reactor at the Frank Laboratory of Neutron Physics, Joint Institute of Nuclear Research, Dubna, Russia. (authors)
Hong, Xinguo; Hao, Quan
2009-01-01
In this paper, we report a method of precise in situ x-ray scattering measurements on protein solutions using small stationary sample cells. Although reduction in the radiation damage induced by intense synchrotron radiation sources is indispensable for the correct interpretation of scattering data, there is still a lack of effective methods to overcome radiation-induced aggregation and extract scattering profiles free from chemical or structural damage. It is found that radiation-induced aggregation mainly begins on the surface of the sample cell and grows along the beam path; the diameter of the damaged region is comparable to the x-ray beam size. Radiation-induced aggregation can be effectively avoided by using a two-dimensional scan (2D mode), with an interval as small as 1.5 times the beam size, at low temperature (e.g., 4 °C). A radiation sensitive protein, bovine hemoglobin, was used to test the method. A standard deviation of less than 5% in the small angle region was observed from a series of nine spectra recorded in 2D mode, in contrast to the intensity variation seen using the conventional stationary technique, which can exceed 100%. Wide-angle x-ray scattering data were collected at a standard macromolecular diffraction station using the same data collection protocol and showed a good signal/noise ratio (better than the reported data on the same protein using a flow cell). The results indicate that this method is an effective approach for obtaining precise measurements of protein solution scattering.
International Nuclear Information System (INIS)
Hong Xinguo; Hao Quan
2009-01-01
In this paper, we report a method of precise in situ x-ray scattering measurements on protein solutions using small stationary sample cells. Although reduction in the radiation damage induced by intense synchrotron radiation sources is indispensable for the correct interpretation of scattering data, there is still a lack of effective methods to overcome radiation-induced aggregation and extract scattering profiles free from chemical or structural damage. It is found that radiation-induced aggregation mainly begins on the surface of the sample cell and grows along the beam path; the diameter of the damaged region is comparable to the x-ray beam size. Radiation-induced aggregation can be effectively avoided by using a two-dimensional scan (2D mode), with an interval as small as 1.5 times the beam size, at low temperature (e.g., 4 deg. C). A radiation sensitive protein, bovine hemoglobin, was used to test the method. A standard deviation of less than 5% in the small angle region was observed from a series of nine spectra recorded in 2D mode, in contrast to the intensity variation seen using the conventional stationary technique, which can exceed 100%. Wide-angle x-ray scattering data were collected at a standard macromolecular diffraction station using the same data collection protocol and showed a good signal/noise ratio (better than the reported data on the same protein using a flow cell). The results indicate that this method is an effective approach for obtaining precise measurements of protein solution scattering.
International Nuclear Information System (INIS)
Efimov, G.V.; Ivanov, M.A.; Rusetskij, A.G.
1989-01-01
The S-wave πN-scattering lengths and the (pπ - )-atom lifetime are in the quark confinement model. Nucleon is treated as a quark-diquark system. The fulfillment of the Weinberg-Tomozawa relations is checked. The agreement is achieved with the experiment and with the results obtained within other approaches. 32 refs.; 5 figs.; 2 tabs
Kusmin, A.; Bouwman, W. G.; van Well, A. A.; Pappas, C.
2017-06-01
We describe theoretical and practical aspects of spin-echo modulated small-angle neutron scattering (SEMSANS) as well as the potential combination with SANS. Based on the preliminary technical designs of SKADI (a SANS instrument proposed for the European Spallation Source) and a SEMSANS add-on, we assess the practicability, feasibility and scientific merit of a combined SANS and SEMSANS setup by calculating tentative SANS and SEMSANS results for soft matter, geology and advanced material samples that have been previously studied by scattering methods. We conclude that lengths from 1 nm up to 0.01 mm can be observed simultaneously in a single measurement. Thus, the combination of SANS and SEMSANS instrument is suited for the simultaneous observation of a wide range of length scales, e.g. for time-resolved studies of kinetic processes in complex multiscale systems.
Small angle scattering methods to study porous materials under high uniaxial strain
Energy Technology Data Exchange (ETDEWEB)
Le Floch, Sylvie, E-mail: sylvie.le-floch@univ-lyon1.fr; Balima, Félix; Pischedda, Vittoria; Legrand, Franck; San-Miguel, Alfonso [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France)
2015-02-15
We developed a high pressure cell for the in situ study of the porosity of solids under high uniaxial strain using neutron small angle scattering. The cell comprises a hydraulically actioned piston and a main body equipped with two single-crystal sapphire windows allowing for the neutron scattering of the sample. The sample cavity is designed to allow for a large volume variation as expected when compressing highly porous materials. We also implemented a loading protocol to adapt an existing diamond anvil cell for the study of porous materials by X-ray small angle scattering under high pressure. The two techniques are complementary as the radiation beam and the applied pressure are in one case perpendicular to each other (neutron cell) and in the other case parallel (X-ray cell). We will illustrate the use of these two techniques in the study of lamellar porous systems up to a maximum pressure of 0.1 GPa and 0.3 GPa for the neutron and X-ray cells, respectively. These devices allow obtaining information on the evolution of porosity with pressure in the pore dimension subdomain defined by the wave-numbers explored in the scattering process. The evolution with the applied load of such parameters as the fractal dimension of the pore-matrix interface or the apparent specific surface in expanded graphite and in expanded vermiculite is used to illustrate the use of the high pressure cells.
A multifrequency MUSIC algorithm for locating small inhomogeneities in inverse scattering
International Nuclear Information System (INIS)
Griesmaier, Roland; Schmiedecke, Christian
2017-01-01
We consider an inverse scattering problem for time-harmonic acoustic or electromagnetic waves with sparse multifrequency far field data-sets. The goal is to localize several small penetrable objects embedded inside an otherwise homogeneous background medium from observations of far fields of scattered waves corresponding to incident plane waves with one fixed incident direction but several different frequencies. We assume that the far field is measured at a few observation directions only. Taking advantage of the smallness of the scatterers with respect to wavelength we utilize an asymptotic representation formula for the far field to design and analyze a MUSIC-type reconstruction method for this setup. We establish lower bounds on the number of frequencies and receiver directions that are required to recover the number and the positions of an ensemble of scatterers from the given measurements. Furthermore we briefly sketch a possible application of the reconstruction method to the practically relevant case of multifrequency backscattering data. Numerical examples are presented to document the potentials and limitations of this approach. (paper)
Nucleon-nucleon scattering studies at small angles at COSY-ANKE
Energy Technology Data Exchange (ETDEWEB)
Bagdasarian, Zara [Forschungszentrum Juelich, Juelich (Germany); Tbilisi State University, Tbilisi (Georgia); Collaboration: ANKE-Collaboration
2015-07-01
The most accepted approach to describe nucleon-nucleon (NN) interaction is the partial wave analysis (PWA). The SAID database and analysis program comprise various experimental observables at different energies over the full angular range and express them in the partial waves. The goal of the experiments held at COSY-Juelich is to provide SAID with new valuable measurements. Scattering data was taken at small angles for six beam energies between 0.8 and 2.4 GeV with polarized proton beam incident on both proton and deuteron unpolarized targets using the ANKE spectrometer. First, the results of the proton-proton (pp) scattering analyzing power and cross section are presented. While pp data closes a very important gap at small angles in the database, proton-neutron (pn) data is a crucial contribution to the almost non-explored pn database above 800 MeV. Therefore, the talk will mainly concentrate on the proton-deuteron (pd) scattering studies, which includes the overview of the older COSY experiments with polarized deuteron beam, and the abovementioned new experiment with polarized proton beam and unpolarized deuteron target. The presentation will show the most recent results of the analyzing powers of pd elastic and pn scattering.
Modelling small-angle scattering data from complex protein-lipid systems
DEFF Research Database (Denmark)
Kynde, Søren Andreas Røssell
This thesis consists of two parts. The rst part is divided into five chapters. Chapter 1 gives a general introduction to the bio-molecular systems that have been studied. These are membrane proteins and their lipid environments in the form of phospholipid nanodiscs. Membrane proteins...... the techniques very well suited for the study of the nanodisc system. Chapter 3 explains two different modelling approaches that can be used in the analysis of small-angle scattering data from lipid-protein complexes. These are the continuous approach where the system of interest is modelled as a few regular...... combine the bene ts of each of the methods and give unique structural information about relevant bio-molecular complexes in solution. Chapter 4 describes the work behind a proposal of a small-angle neutron scattering instrument for the European Spallation Source under construction in Lund. The instrument...
In situ microfluidic dialysis for biological small-angle X-ray scattering
DEFF Research Database (Denmark)
Skou, Magda; Skou, Soren; Jensen, Thomas Glasdam
2014-01-01
Owing to the demand for low sample consumption and automated sample changing capabilities at synchrotron small-angle X-ray (solution) scattering (SAXS) beamlines, X-ray microfluidics is receiving continuously increasing attention. Here, a remote-controlled microfluidic device is presented for sim...... in incidental sample purification. Hence, this versatile microfluidic device enables investigation of experimentally induced structural changes under dynamically controllable sample conditions. (C) 2014 International Union of Crystallography......Owing to the demand for low sample consumption and automated sample changing capabilities at synchrotron small-angle X-ray (solution) scattering (SAXS) beamlines, X-ray microfluidics is receiving continuously increasing attention. Here, a remote-controlled microfluidic device is presented...
X-ray and neutron small-angle scattering studies of human serum lipoproteins
International Nuclear Information System (INIS)
Luzzati, V.; Tardieu, A.; Mateu, L.; Sardet, C.; Stuhrmann, H.B.; Aggerbeck, L.; Scanu, A.M.
1976-01-01
The paper describes an extended x-ray study of two types of human serum lipoproteins and a neutron study of one of them. The results are similar and to some extent complementary. Serum lipoproteins provide an excellent illustration of the wealth of information that can be obtained by a small-angle scattering approach to the structure of particles with non-uniform density distribution, by using solvents of variable density
Study of humic acids by small-angle X-ray and neutron scattering
International Nuclear Information System (INIS)
Timchenko, A.; Trubetskaya, O.; Kihara, H.
1999-01-01
Humic acids are an important component of natural ecological system and represent a polydisperse complex of natural biopolymers with molecular masses from several to hundreds kilodaltons. They are both a source of organic compounds and a protector against anthropogenic pollutions of biosphere. The aim of the report is to underline some possibilities of small-angle X-ray and neutron scattering to study HA and their fractions. (author)
Calculation of atom ranges in solids for quasi-small-angle scattering
International Nuclear Information System (INIS)
Pustovit, A.N.
2004-01-01
A formula for quasi-small-angle scattering of atomic particle and power law interaction potential have been used for the calculation of the differential cross-section, elastic stopping cross-section and a mean projected range in a solid. It is found that the limit energy transfer in the collisions depends on the screening of the power law interaction potentials. The calculated mean ranges in matter are compared with experimental data [ru
Small angle neutron scattering study of creep deformation and fracture of type 304 stainless steel
International Nuclear Information System (INIS)
Yoo, M.H.; Ogle, J.C.; Schneibel, J.H.; Swindeman, R.W.
1983-01-01
A small-angle neutron scattering (SANS) study has been performed to determine the size distribution of carbide precipitates that were formed during creep deformation in type 304 stainless steel. The hardening mechanism during primary creep by a fine dispersion of carbide particles in the matrix was confirmed by the SANS measurement and also by direct TEM observations. The size distribution of creep-induced cavities was also determined by SANS measurements after post-creep solution heat treatment. (author)
Small angle neutron scattering study of creep deformation and fracture of Type 304 stainless steel
International Nuclear Information System (INIS)
Yoo, M.H.; Ogle, J.C.; Schneibel, J.H.; Swindeman, R.W.
1982-01-01
A small-angle neutron scattering (SANS) study has been performed to determine the size distribution of carbide precipitates that were formed during creep deformation in Type 304 stainless steel. The hardening mechanism during primary creep by a fine dispersion of carbide particles in the matrix was confirmed by the SANS measurement and also by direct TEM observations. The size distribution of creep-induced cavities was also determined by SANS measurements after post-creep solution heat treatment
Small angle neutron scattering form polymer melts: structural investigation and phase behaviour
International Nuclear Information System (INIS)
Ertugrul, O.
2004-01-01
The Small-Angle Neutron Scattering (SANS) techniques have been used to study the structural properties and phase behavior of polymer melts. A model based on Random Phase Approximation (RPA) is proposed to predict the experimental data. By fitting the model to data we could be able to obtain radius of gyration (a measure of size of a polymer) and phase transition for the sample. (author)
Two-dimensional position-sensitive detectors for small-angle neutron scattering
International Nuclear Information System (INIS)
McElhaney, S.A.; Vandermolen, R.I.
1990-05-01
In this paper, various detectors available for small angle neutron scattering (SANS) are discussed, along with some current developments being actively pursued. A section has been included to outline the various methodologies of position encoding/decoding with discussions on trends and limitations. Computer software/hardware vary greatly from institute and experiment and only a general discussion is given to this area. 85 refs., 33 figs
Creanga, Dorina; Balasoiu, Maria; Soloviov, Dmitro; Balasoiu-Gaina, Alexandra-Maria; Puscasu, Emil; Lupu, Nicoleta; Stan, Cristina
2018-03-01
Preliminary small-angle neutron scattering investigations on aqueous suspensions of several cobalt doped ferrites (CoxFe3-xO4, x=0; 0.5; 1) nanoparticles prepared by chemical co-precipitation method, are reported. The measurements were accomplished at the YuMO instrument in function at the IBR-2 reactor. Results of intermediary data treatment are presented and discussed.
Dispersion forces and small-angle neutron scattering from liquid noble metals
International Nuclear Information System (INIS)
March, N.H.
1988-01-01
Maggs and Ashcroft [Phys. Rev. letts., 59,113 (1987)] have re-opened the question of the analogy between the cohesion of a molecular crystal, in which dispersion forces play a major role, and that in a metal crystal with polarizable ion cores. It is pointed out that small-angle neutron scattering from liquid noble metals could be used to test their predictions. (author)
DEFF Research Database (Denmark)
Midtgaard, Søren Roi; Darwish, Tamim A.; Pedersen, Martin Cramer
2018-01-01
A novel and generally applicable method for determining structures of membrane proteins in solution via small-angle neutron scattering (SANS) is presented. Common detergents for solubilizing membrane proteins were synthesized in isotope-substituted versions for utilizing the intrinsic neutron sca...... solution structure determination of membrane proteins by SANS and subsequent data analysis available to non-specialists. This article is protected by copyright. All rights reserved....
Cramer, Robert Grewelle.
1982-01-01
Approved for public release; distribution unlimited A dual beam apparatus was developed which simultaneously measured particle size (D32) at the entrance and exit of an exhaust nozzle of a small solid propellant rocket motor. The diameters were determined using measurements of dif fractiveiy scattered laser power spectra. The apparatus was calibrated by using spherical glass beads and aluminum oxide powder. Measurements were successfully made at both locations. Because of...
Conformation of comb liquid crystal polymers by neutron small angle scattering
International Nuclear Information System (INIS)
Noirez, L.; Pepy, G.
1988-01-01
A review is made of the direct information obtained by small angle neutron scattering about the anisotropy of the components parallel and perpendicular to the orienting magnetic field of the radius of gyration of comb like liquid crystal polymers. The behaviour of the conformation versus temperature is reported for several samples. Until now all samples show an oblate conformation in the smectic phase and probably the whole range of the nematic phase. The results are compared with the available theoretical predictions
Small-angle light scattering studies of dense AOT-water-decane microemulsions
International Nuclear Information System (INIS)
Micali, N.; Trusso, S.; Mallamace, F.; Chen, S.H.
1996-01-01
It is performed extensive studies of a three-component microemulsion system composed of AOT-water-decane using small-angle light scattering (SALS). The small-angle scattering intensities are measured in the angular interval 0.001-0.1 radians, corresponding to a Bragg wave number range of 0.14 μm -1 -1 . The measurements were made by changing temperature and volume fraction φ of the dispersed phase in the range 0.65< φ < 0.75. All samples have a fixed water-to-AOT molar ratio, w [water[/[AOT[ = 40.8, in order to keep the same average droplet size in the stable one-phase region. With the SALS technique it is observed all the phase boundaries of a very complex phase diagram with a percolation line and many structural organizations within it. It is observed at the percolation transition threshold, a scaling behavior of the intensity data. In addition it is described in detail a structural transition from a droplet microemulsion to a bi continuous one a suggested by a recent small-angle neutron scattering experiment. From the data analysis it is show that both the percolation phenomenon and this novel structural transition are described from a large-scale aggregation between microemulsion droplets
Scott, David J
2016-12-01
Hydrodynamic studies of the solution properties of proteins and other biological macromolecules are often hard to interpret when the sample is present at a reasonably concentrated solution. The reason for this is that solutions exhibit deviations from ideal behaviour which is manifested as thermodynamic non-ideality. The range of concentrations at which this behaviour typically is exhibited is as low as 1-2 mg/ml, well within the range of concentrations used for their analysis by techniques such as small-angle scattering. Here we discuss thermodynamic non-ideality used previously used in the context of light scattering and sedimentation equilibrium analytical ultracentrifugation and apply it to the Guinier region of small-angle scattering data. The results show that there is a complementarity between the radially averaged structure factor derived from small-angle X-ray scattering/small-angle neutron scattering studies and the second virial coefficient derived from sedimentation equilibrium analytical ultracentrifugation experiments.
Small angle neutron scattering measurements of magnetic cluster sizes in magnetic recorging disks
Toney, M
2003-01-01
We describe Small Angle Neutron Scattering measurements of the magnetic cluster size distributions for several longitudinal magnetic recording media. We find that the average magnetic cluster size is slightly larger than the average physical grain size, that there is a broad distribution of cluster sizes, and that the cluster size is inversely correlated to the media signal-to-noise ratio. These results show that intergranular magnetic coupling in these media is small and they provide empirical data for the cluster-size distribution that can be incorporated into models of magnetic recording.
Evaluation of attenuation and scatter correction requirements in small animal PET and SPECT imaging
Konik, Arda Bekir
Positron emission tomography (PET) and single photon emission tomography (SPECT) are two nuclear emission-imaging modalities that rely on the detection of high-energy photons emitted from radiotracers administered to the subject. The majority of these photons are attenuated (absorbed or scattered) in the body, resulting in count losses or deviations from true detection, which in turn degrades the accuracy of images. In clinical emission tomography, sophisticated correction methods are often required employing additional x-ray CT or radionuclide transmission scans. Having proven their potential in both clinical and research areas, both PET and SPECT are being adapted for small animal imaging. However, despite the growing interest in small animal emission tomography, little scientific information exists about the accuracy of these correction methods on smaller size objects, and what level of correction is required. The purpose of this work is to determine the role of attenuation and scatter corrections as a function of object size through simulations. The simulations were performed using Interactive Data Language (IDL) and a Monte Carlo based package, Geant4 application for emission tomography (GATE). In IDL simulations, PET and SPECT data acquisition were modeled in the presence of attenuation. A mathematical emission and attenuation phantom approximating a thorax slice and slices from real PET/CT data were scaled to 5 different sizes (i.e., human, dog, rabbit, rat and mouse). The simulated emission data collected from these objects were reconstructed. The reconstructed images, with and without attenuation correction, were compared to the ideal (i.e., non-attenuated) reconstruction. Next, using GATE, scatter fraction values (the ratio of the scatter counts to the total counts) of PET and SPECT scanners were measured for various sizes of NEMA (cylindrical phantoms representing small animals and human), MOBY (realistic mouse/rat model) and XCAT (realistic human model
SCT: a suite of programs for comparing atomistic models with small-angle scattering data.
Wright, David W; Perkins, Stephen J
2015-06-01
Small-angle X-ray and neutron scattering techniques characterize proteins in solution and complement high-resolution structural studies. They are of particular utility when large proteins cannot be crystallized or when the structure is altered by solution conditions. Atomistic models of the averaged structure can be generated through constrained modelling, a technique in which known domain or subunit structures are combined with linker models to produce candidate global conformations. By randomizing the configuration adopted by the different elements of the model, thousands of candidate structures are produced. Next, theoretical scattering curves are generated for each model for trial-and-error fits to the experimental data. From these, a small family of best-fit models is identified. In order to facilitate both the computation of theoretical scattering curves from atomistic models and their comparison with experiment, the SCT suite of tools was developed. SCT also includes programs that provide sequence-based estimates of protein volume (either incorporating hydration or not) and add a hydration layer to models for X-ray scattering modelling. The original SCT software, written in Fortran, resulted in the first atomistic scattering structures to be deposited in the Protein Data Bank, and 77 structures for antibodies, complement proteins and anionic oligosaccharides were determined between 1998 and 2014. For the first time, this software is publicly available, alongside an easier-to-use reimplementation of the same algorithms in Python. Both versions of SCT have been released as open-source software under the Apache 2 license and are available for download from https://github.com/dww100/sct.
Small angle neutron scattering. Report of a coordinated research project 2000-2003
International Nuclear Information System (INIS)
2006-03-01
Small angle neutron scattering (SANS) is a powerful technique for studying macro structures like polymers, precipitates in metallurgical specimens, biological molecules, micelles and magnetic systems like ferrofluids. Neutron scattering has an advantage over X ray scattering (XSAXS) due to selective absorption and scattering cross section of neutrons across the periodic table. It is possible to develop and use a SANS instrument even with a medium flux reactor. The present CRP was aimed at the development of components like collimators, monochromators, position sensitive detectors (PSD) etc. for improving the throughput of the instrument and foster the effective utilization of research reactors, as well as to provide a link between developing and developed facilities. The CRP was launched with the first research coordination meeting (RCM) in 2000 to refine the project proposals and define the action plans and partnerships. There were eight research contracts and four research agreements. Good partnerships were established between various participants with collaborations among participants from various countries including those from developing and developed countries. The progress of the individual projects and team work under the CRP was evaluated and discussed during the second RCM and the action plan for the final phase was formulated. The results of the work done under the CRP were then reviewed in the final RCM held in Vienna, December 2003. This publication presents the results of the work carried out by the participants under the CRP at their respective institutions. The information will be useful for the users and operators of research reactors in developing an instrument and building collaborations for capacity building. The development of collimators, detector assemblies, utilization of the SANS for microstructural characterization of advanced materials , development and design of a ultra small angle neutron scattering (USANS) and proposals for a new SANS
Application of small-angle X-ray scattering for differentiation among breast tumors
International Nuclear Information System (INIS)
Changizi, V.; Kheradmand, A. Arab; Oghabian, M.A.
2008-01-01
Small-angle X-ray scattering (SAXS) is an X-ray diffraction-based technique where a narrow collimated beam of X-rays is focused onto a sample and the scattered X-rays recorded by a detector. The pattern of the scattered X-rays carries information on the molecular structure of the material. As breast cancer is the most widespread cancer in women and differentiation among its tumors is important, this project compared the results of coherent X-ray scattering measurements obtained from benign and malignant breast tissues. The energy-dispersive method with a setup including X-ray tube, primary collimator, sample holder, secondary collimator and high-purity germanium (HpGe) detector was used. One hundred thirty-one breast-tissue samples, including normal, fibrocystic changes and carcinoma, were studied at the 6 deg scattering angle. Diffraction profiles (corrected scattered intensity versus momentum transfer) of normal, fibrocystic changes and carcinoma were obtained. These profiles showed a few peak positions for adipose (1.15 ± 0.06 nm -1 ), mixed normal (1.15 ± 0.06 nm -1 and 1.4 ± 0.04 nm -1 ), fibrocystic changes (1.46 ± 0.05 nm -1 and 1.74 ± 0.04 nm -1 ) and carcinoma (1.55 ± 0.04 nm -1 , 1.73 ± 0.06 nm -1 , 1.85 ± 0.05 nm -1 ). We were able to differentiate between normal, fibrocystic changes (benign) and carcinoma (malignant) breast tissues by SAXS. However, we were unable to differentiate between different types of carcinoma. (author)
Application of small-angle X-ray scattering for differentiation among breast tumors
Directory of Open Access Journals (Sweden)
Changizi V
2008-01-01
Full Text Available Small-angle X-ray scattering (SAXS is an X-ray diffraction-based technique where a narrow collimated beam of X-rays is focused onto a sample and the scattered X-rays recorded by a detector. The pattern of the scattered X-rays carries information on the molecular structure of the material. As breast cancer is the most widespread cancer in women and differentiation among its tumors is important, this project compared the results of coherent X-ray scattering measurements obtained from benign and malignant breast tissues. The energy-dispersive method with a setup including X-ray tube, primary collimator, sample holder, secondary collimator and high-purity germanium (HpGe detector was used. One hundred thirty-one breast-tissue samples, including normal, fibrocystic changes and carcinoma, were studied at the 6° scattering angle. Diffraction profiles (corrected scattered intensity versus momentum transfer of normal, fibrocystic changes and carcinoma were obtained. These profiles showed a few peak positions for adipose (1.15 ± 0.06 nm -1 , mixed normal (1.15 ± 0.06 nm -1 and 1.4 ± 0.04 nm -1 , fibrocystic changes (1.46 ± 0.05 nm -1 and 1.74 ± 0.04 nm -1 and carcinoma (1.55 ± 0.04 nm -1 , 1.73 ± 0.06 nm -1 , 1.85 ± 0.05 nm -1 . We were able to differentiate between normal, fibrocystic changes (benign and carcinoma (malignant breast tissues by SAXS. However, we were unable to differentiate between different types of carcinoma.
International Nuclear Information System (INIS)
Bridges, Craig A.; Paranthaman, Mariappan Parans; Sun, Xiao-Guang; Zhao, Jinkui; Dai, Sheng
2012-01-01
The aim of this work was to better understand the electrochemical processes occurring during the cycling of a lithium-ion half-cell containing ordered mesoporous hard carbon using time-resolved in situ small-angle neutron scattering (SANS). Utilizing electrolytes containing mixtures of deuterated (2H) and non-deuterated (1H) carbonates, we have addressed the challenging task of monitoring the formation and evolution of the solid-electrolyte interphase (SEI) layer. An evolution occurs in the SEI layer during discharge from a composition dominated by a higher scattering length density (SLD) lithium salt, to a lower SLD lithium salt for the ethylene carbonate/dimethyl carbonate (EC/DMC) mixture employed. By comparing half-cells containing different solvent deuteration levels, we show that it is possible to observe both SEI formation and lithium intercalation occurring concurrently at the low voltage region in which lithium intercalates into the hard carbon. These results demonstrate that SANS can be employed to monitor complicated electrochemical processes occurring in rechargeable batteries, in a manner that simultaneously provides information on the composition and microstructure of the electrode.
Diffusion effects on volume-selective NMR at small length scales
International Nuclear Information System (INIS)
Gaedke, Achim
2009-01-01
In this thesis, the interplay between diffusion and relaxation effects in spatially selective NMR experiments at short length scales is explored. This is especially relevant in the context of both conventional and mechanically detected MRI at (sub)micron resolution in biological specimens. Recent results on selectively excited very thin slices showed an in-slice-magnetization recovery orders of magnitude faster than the longitudinal relaxation time T1. However, those experiments were run on fully relaxed samples while MRI and especially mechanically detected NMR experiments are typically run in a periodic fashion with repetition times far below T1. The main purpose of this work therefore was to extend the study of the interplay between diffusion and longitudinal relaxation to periodic excitations. In some way, this is inverse phenomenon to the DESIRE (Diffusive Enhancement of SIgnal and REsolution) approach, proposed 1992 by Lauterbur. Experiments on periodically excited thin slices were carried out at a dedicated static field gradient cryomagnet with magnetic field gradients up to 180 T/m. In order to obtain plane slices, an appropriate isosurface of the gradient magnet had to be identified. It was found at a field of 3.8 T with a gradient of 73 T/m. In this field, slices down to a thickness of 3.2 μm could be excited. The detection of the NMR signal was done using FIDs instead of echoes as the excitation bandwidth of those thin slices is sufficiently small to observe FIDs which are usually considered to be elusive to detection in such strong static field gradients. A simulation toolbox based on the full Bloch-Torrey-equation was developed to describe the excitation and the formation of NMR signals under those unusual conditions as well as the interplay of diffusion and magnetization recovery. Both the experiments and the simulations indicate that diffusion effects lead to a strongly enhanced magnetization modulation signal also under periodic excitation
International Nuclear Information System (INIS)
Zemlyanaya, E.V.; Kiselev, M.A.
2002-01-01
On the basis of the model of separated form-factors, a code for fitting of small-angle neutron scattering spectra of the polydispersed vesicle population has been developed with corrections to the resolution function of the YuMO spectrometer. Vesicle and membrane bilayer parameters have been analyzed for various hierarchical models of the neutron scattering length density across the membrane. It was shown that hydration of vesicle can be described by the linear distribution function of water molecules. For the first time from the small-angle experiment, without additional methods, the average radius and polydispersity of the vesicle population, thickness of the membrane bilayer, thickness of hydrophobic and hydrophilic parts of bilayer, water distribution function and number of water molecules in the hydrophilic part have been calculated. (author)
Small-angle x-ray scattering investigation of the solution structure of troponin C
International Nuclear Information System (INIS)
Hubbard, S.R.; Hodgson, K.O.; Doniach, S.
1988-01-01
X-ray crystallographic studies of troponin C have revealed a novel protein structure consisting of two globular domains, each containing two Ca 2+ -binding sites, connected via a nine-turn alpha-helix, three turns of which are fully exposed to solvent. Since the crystals were grown at pH approximately 5, it is of interest to determine whether this structure is applicable to the protein in solution under physiological conditions. We have used small-angle x-ray scattering to examine the solution structure of troponin C at pH 6.8 and the effect of Ca 2+ on the structure. The scattering data are consistent with an elongated structure in solution with a radius of gyration of approximately 23.0 A, which is quite comparable to that computed for the crystal structure. The experimental scattering profile and the scattering profile computed from the crystal structure coordinates do, however, exhibit differences at the 40-A level. A weak Ca 2+ -facilitated dimerization of troponin C was observed. The data rule out large Ca 2+ -induced structural changes, indicating rather that the molecule with Ca 2+ bound is only slightly more compact than the Ca 2+ -free molecule
International Nuclear Information System (INIS)
Chew, H.; McNulty, P.J.
1978-01-01
A model for the fluorescence and Raman scattering by molecules that comprise or are embedded in small particles was developed and numerical calculations performed. The emphasis during this first year of the contract was on writing and testing the computer programs necessary for numerical calculations and on demonstrating the extent of the potential effects that the geometrical and optical properties of the particle would have on the Raman and fluorescent emissions. For the purpose of demonstrating effects emphasis was focused upon the case of isotropically polarizable molecules that fluoresce or Raman scatter through electric dipole transitions. Some preliminary results are described. One result of these investigations that is of particular significance for remote sensing of pollutants is that it would be a serious mistake to use inelastic scattering techniques such as Raman and fluorescent scattering for quantitative assay of specific molecules in aerosols containing particulates without taking into account the size, structure and refractive index of the particles. A list of publications is included
Directory of Open Access Journals (Sweden)
Krit Koyvanich
2013-01-01
Full Text Available The segmentation between rigid and rubbery chains in polyurethanes (PUs influences polymeric properties and implementations. Several models have successfully been proposed to visualize the configuration between the hard segment (HS and soft segment (SS. For particulate PU composites, the arrangement of HS and SS is more complicated because the fillers tend to disrupt the chain formation and segmentation. In this work, the effect of ferromagnetic cobalt (Co powders (average diameter 2 μm on PU synthesized from a reaction between polyether polyol (soft segment and diphenylmethane-4,4′-diisocyanate (hard segment was studied with varying loadings (0, 20, 40, and 60 wt.%. The 300 μm thick PU/Co samples were tape-casted and then received heat treatment at 80°C for 180 min. From synchrotron small angle X-ray scattering (SAXS, the plot of the X-ray scattering intensity (I against the scattering vector (q exhibited a typical single peak of PU whose intensity was reduced by the increase in the Co loading. Characteristic SAXS peaks in the case of 0-20 wt.% Co agreed well with the scattering by globular hard segment domains according to Zernike-Prins and Percus-Yevick models. The higher Co loadings led to larger deviations from all theoretical models.
Traceable size determination of PMMA nanoparticles based on Small Angle X-ray Scattering (SAXS)
Energy Technology Data Exchange (ETDEWEB)
Gleber, G; Cibik, L; Mueller, P; Krumrey, M [Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, 10587 Berlin (Germany); Haas, S; Hoell, A, E-mail: gudrun.gleber@ptb.d [Helmholtz-Zentrum-Berlin fuer Materialien und Energie (HZB), Albert-Einstein-Strasse 15, 12489 Berlin (Germany)
2010-10-01
The size and size distribution of PMMA nanoparticles has been investigated with SAXS (small angle X-ray scattering) using monochromatized synchrotron radiation. The uncertainty has contributions from the wavelength or photon energy of the radiation, the scattering angle and the fit procedure for the obtained scattering curves. The wavelength can be traced back to the lattice constant of silicon, and the scattering angle is traceable via geometric measurements of the detector pixel size and the distance between the sample and the detector. SAXS measurements and data evaluations have been performed at different distances and photon energies for two PMMA nanoparticle suspensions with low polydispersity and nominal diameters of 108 nm and 192 nm, respectively, as well as for a mixture of both. The relative variation of the diameters obtained for different experimental conditions was below {+-} 0.3 %. The determined number-weighted mean diameters of (109.0 {+-} 0.7) nm and (188.0 {+-} 1.3) nm, respectively, are close to the nominal values.
Traceable size determination of PMMA nanoparticles based on Small Angle X-ray Scattering (SAXS)
Gleber, G.; Cibik, L.; Haas, S.; Hoell, A.; Müller, P.; Krumrey, M.
2010-10-01
The size and size distribution of PMMA nanoparticles has been investigated with SAXS (small angle X-ray scattering) using monochromatized synchrotron radiation. The uncertainty has contributions from the wavelength or photon energy of the radiation, the scattering angle and the fit procedure for the obtained scattering curves. The wavelength can be traced back to the lattice constant of silicon, and the scattering angle is traceable via geometric measurements of the detector pixel size and the distance between the sample and the detector. SAXS measurements and data evaluations have been performed at different distances and photon energies for two PMMA nanoparticle suspensions with low polydispersity and nominal diameters of 108 nm and 192 nm, respectively, as well as for a mixture of both. The relative variation of the diameters obtained for different experimental conditions was below ± 0.3 %. The determined number-weighted mean diameters of (109.0 ± 0.7) nm and (188.0 ± 1.3) nm, respectively, are close to the nominal values.
Traceable size determination of PMMA nanoparticles based on Small Angle X-ray Scattering (SAXS)
International Nuclear Information System (INIS)
Gleber, G; Cibik, L; Mueller, P; Krumrey, M; Haas, S; Hoell, A
2010-01-01
The size and size distribution of PMMA nanoparticles has been investigated with SAXS (small angle X-ray scattering) using monochromatized synchrotron radiation. The uncertainty has contributions from the wavelength or photon energy of the radiation, the scattering angle and the fit procedure for the obtained scattering curves. The wavelength can be traced back to the lattice constant of silicon, and the scattering angle is traceable via geometric measurements of the detector pixel size and the distance between the sample and the detector. SAXS measurements and data evaluations have been performed at different distances and photon energies for two PMMA nanoparticle suspensions with low polydispersity and nominal diameters of 108 nm and 192 nm, respectively, as well as for a mixture of both. The relative variation of the diameters obtained for different experimental conditions was below ± 0.3 %. The determined number-weighted mean diameters of (109.0 ± 0.7) nm and (188.0 ± 1.3) nm, respectively, are close to the nominal values.
Small-angle neutron scattering of short-segment block polymers
International Nuclear Information System (INIS)
Cooper, S.L.; Miller, J.A.; Homan, J.G.
1988-01-01
Small-angle neutron scattering has been used to investigate the chain conformation of the hard and soft segments in short-segment polyether-polyester and polyether-polyurethane materials. The method of phase-contrast matching was used to eliminate the coherent neutron scattering due to the two-phase microstructure in these materials. The partial deutero-labelling necessary for this technique also provides a neutron scattering contrast between labelled and unlabelled segments. The structure factor for each segment type is determined from the coherent scattering from such deuterolabelled materials. In all of the materials examined, the poly(tetramethylene oxide) (PTMO) soft segment was found to be in a slightly extended conformation relative to bulk PTMO at room temperature. Upon heating, the PTMO segments contracted to a more relaxed conformation. In one polyether-polyurethane sample, the radius of gyration of the PTMO segment increased again at high temperatures, indicating phase mixing. The hardsegment radii of gyration in the polyether-polyester materials were found to increase with temperature, indicating a transition from a chain-folded conformation at room temperature to a more extended conformation at higher temperatures. The radius of gyration of the whole polyether-polyester chain first decreased then increased with temperature, indicative of the combined effects of the component hard- and soft-segment chain conformation changes. The hard-segment radius of gyration in a polyether-polyurethane was observed to decrease with temperature. (orig.)
International Nuclear Information System (INIS)
Liao, G.; Xie, Y.; Ludwig, K.F. Jr.; Bansil, R.; Gallagher, P.; Xie, Y.; Gallagher, P.
1999-01-01
We present synchrotron-based time-resolved small-angle x-ray scattering (SAXS) measurements of spinodal decomposition in a covalently cross-linked N-isopropylacrylamide gel. The range of wave numbers examined is well beyond the position of the maximum in the structure factor S(q,t). The equilibrium structure factor is described by the sum of a Lorentzian and a Gaussian. Following a temperature jump into the two phase region, the scattered intensity increases with time and eventually saturates. For early times the linear Cahn-Hilliard-Cook (CHC) theory can be used to describe the time evolution of the scattered intensity. From this analysis we found that the growth rate R(q) is linearly dependent on q 2 , in agreement with mean-field theoretical predictions. However the Onsager transport coefficient Λ(q)∼q -4 , which is stronger than the q dependence predicted by the mean-field theory. We found that the growth rate R(q)>0, even though the wave numbers q probed by SAXS are greater than √ (2) q m where q m is the position of the peak of S(q,t), also in agreement with the mean-field predictions for a deep quench. We have also examined the range of validity of the linear CHC theory, and found that its breakdown occurs earlier at higher wave numbers. At later times, a pinning of the structure was observed. The relaxation to a final, microphase-separated morphology is faster and occurs earlier at the highest wave numbers, which probe length scales comparable to the average distance between crosslinks. copyright 1999 The American Physical Society
A small-angle camera for resonant scattering experiments at the storage ring DORIS
International Nuclear Information System (INIS)
Stuhrmann, H.B.; Gabriel, A.
1983-01-01
Resonant small-angle scattering is measured routinely in the wavelength range of 0.6 to 3.25 A with the instrument X15 at the storage ring DORIS. The monochromatic beam with a vertical offset of 1.22 m is achieved by a double monochromator system with a constant exit slit. The small-angle instrument allows for sample-detector distances between 0.37 and 7.33 m. A multiwire proportional counter with a sensitive area of 200 X 200 mm detects the scattered intensity with a spatial resolution of 2 X 2 mm. Its sensitivity can be adapted to the requirements of the experiment by activating a drift chamber of 8 cm depth at the back end of the detector. The performance of the instrument as a function of the wavelength is described. The energy resolution is about 1 eV at the L 3 absorption edge of caesium, as shown by the resonant scattering of ferritin in 30% CsCl solution. (Auth.)
Design Principle of A Small Angle Neutron Scattering Spectrometer. Vol. 2
Energy Technology Data Exchange (ETDEWEB)
Ashry, A [Dept. of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt)
1996-03-01
The design principle of a small angle neutron scattering (SANS) spectrometer is based on producing monochromatic neutron bursts using two phased rotors. The rotors have a number of slots to achieve the highly available intensity of monoenergetic neutrons at the required resolution. The design principle was applied to improve the performance of the pulsed monochromatic double rotor system at ET-RR-1 to operate as SANS spectrometer. It is shown that for rotors having 19 slots each with radius of curvature 96.8 cm, the intensity gain factor is 13. The proposed SANS spectrometer could cover the neutron wavelength range from 2 A{sup {omicron}} up to 6 A{sup {omicron}} through small angles of scattering from 5 x 10{sup -3} rad. to 0.1 rad. i.e, the scattering wavevector transfer between 0.6 A{sup {omicron}-1} and 0.01 A{sup {omicron}-1}. The maximum neutron flux density on the specimen is 5 x 10{sup 5} n cm{sup -2} s{sup -1}. 8 figs.
International Nuclear Information System (INIS)
Olah, G.A.; Hjelm, R.P.; Lujan, M. Jr.
1996-01-01
We studied the design and performance of a small-angle neutron scattering (SANS) instrument for a proposed 1 MW, 60 Hz long pulsed spallation source at the Los Alamos Neutron Science Center (LANSCE). An analysis of the effects of source characteristics and chopper performance combined with instrument simulations using the LANSCE Monte Carlo instrument simulations package shows that the T 0 chopper should be no more than 5 m from the source with the frame overlap and frame definition choppers at 5.6 and greater than 7 m, respectively. The study showed that an optimal pulse structure has an exponential decaying tail with τ ∼ 750 μs. The Monte Carlo simulations were used to optimize the LPSS SANS, showing that an optimal length is 18 m. The simulations show that an instrument with variable length is best to match the needs of a given measurement. The performance of the optimized LPSS instrument was found to be comparable with present world standard instruments
International Nuclear Information System (INIS)
Reynolds, Philip A.; McGillivray, Duncan J.; White, John W.; Jackson, Andrew J.; University of Maryland, College Paerk, Maryland, USA
2009-01-01
Full text: We measured ultra small angle neutron scattering (USANS) from polymethylmethacrylate spheres tamped down in air. Two slightly polydisperse pure sphere sizes (1.5/-lm and 7.5/-lm diameter) and five mixtures of these were used. All were loose packed (packing fractions 0.3 to 0.6) with nongravitational forces (e.g., friction) important, preventing close packing. The USANS data is rich in information on powder packing. A modified Percus-Yevick fluid model was used to parametrise the data - adequately but not well. The modifications required introduction of small voids, less than the sphere size, and a parameter reflecting substantial deviation from the Percus-Yevick prediction of the sphere-sphere correlation function. The mixed samples fitted less well, and two further modifying factors were necessary. These were local inhomogeneities, where the concentration of same-size spheres, both large and small, deviated from the mean packing, and a factor accounting for the presence within these 'clusters' of self avoidance of the large spheres (that is large spheres coated with more small spheres than Percus-Yevick would predict). The overall deviations from the hardsphere Percus-Yevick model that we find here suggests fluid models of loose packed powders are unlikely to be successful, but lay the groundwork for future theoretical and computational work.
Small-angle neutron scattering and molecular dynamics structural study of gelling DNA nanostars
Energy Technology Data Exchange (ETDEWEB)
Fernandez-Castanon, J.; Bomboi, F. [Sapienza–Università di Roma, P.le A. Moro 5, 00185 Roma (Italy); Rovigatti, L. [Rudolf Peierls C.T.P., University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria); Zanatta, M. [Dipartimento di Fisica, Università di Perugia, Via Pascoli, 06123 Perugia (Italy); CNR-ISC, UOS Sapienza–Università di Roma, I-00186 Roma (Italy); Paciaroni, A. [Dipartimento di Fisica, Università di Perugia, Via Pascoli, 06123 Perugia (Italy); Comez, L. [Dipartimento di Fisica, Università di Perugia, Via Pascoli, 06123 Perugia (Italy); IOM-CNR, UOS Perugia c/o Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli, 06123 Perugia (Italy); Porcar, L. [Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9 (France); Jafta, C. J. [Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Fadda, G. C. [Laboratoire Léon Brillouin, LLB, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France); Bellini, T. [Department of Medical Biotechnology and Translational Medicine, Università di Milano, I-20133 Milano (Italy); Sciortino, F., E-mail: francesco.sciortino@uniroma1.it [Sapienza–Università di Roma, P.le A. Moro 5, 00185 Roma (Italy); CNR-ISC, UOS Sapienza–Università di Roma, I-00186 Roma (Italy)
2016-08-28
DNA oligomers with properly designed sequences self-assemble into well defined constructs. Here, we exploit this methodology to produce bulk quantities of tetravalent DNA nanostars (each one composed of 196 nucleotides) and to explore the structural signatures of their aggregation process. We report small-angle neutron scattering experiments focused on the evaluation of both the form factor and the temperature evolution of the scattered intensity at a nanostar concentration where the system forms a tetravalent equilibrium gel. We also perform molecular dynamics simulations of one isolated tetramer to evaluate the form factor numerically, without resorting to any approximate shape. The numerical form factor is found to be in very good agreement with the experimental one. Simulations predict an essentially temperature-independent form factor, offering the possibility to extract the effective structure factor and its evolution during the equilibrium gelation.
Energy Technology Data Exchange (ETDEWEB)
Takahashi, Hiroshi [Department of Physics, Gunma University, Maebashi, Gunma (Japan)
2001-03-01
Trehalose protects cells and proteins against various stresses due to low temperatures or dryness. In order to clarify the molecular mechanism of cryoprotective function of trehalose, we have studied the interaction between trehalose and phosphatidylcholine (PC) which is a main lipid component of cell membranes. In this study, the structural change of a binary PC mixture by the presence of trehalose was investigated by means of small angle neutron scattering. The PC binary mixture studied contains dihexanoyl-PC (diC{sub 6}PC) and dihexadecy-PC (DHPC). The former has short hydrocarbon chains and the latter has long hydrocarbon chains. The scattering profiles from the DHPC/diC{sub 6}PC mixture were changed, depending on trehalose concentrations. This change can be interpreted as suggesting that the presence of trehalose reduces the interfacial area between water and PCs. (author)
Kappa-casein micelles: structure, interaction and gelling studied by small-angle neutron scattering.
de Kruif, C G; May, R P
1991-09-01
Small-angle neutron scattering (SANS) measurements on dilute and concentrated dispersions of kappa-casein micelles in a buffer at pH = 6.7 were made using the D11 diffractometer in Grenoble. Results indicate that the micelles have a dense core with a fluffy outer layer. This outer layer appears to give rise to a steeply repulsive interaction on contact. In fact, the hard-sphere model best fits the measured scattering intensities. Adding chymosin to the dispersion initiated a fractal flocculation of the micelles and consecutively a coalescence of the micelles. This unexpected second process resembled that of spinodal demixing. The dispersion phase thus separates into a water and a protein phase on a time scale of hours. The observed phenomona contribute to the understanding of the cheese-making process.
The modular small-angle X-ray scattering data correction sequence.
Pauw, B R; Smith, A J; Snow, T; Terrill, N J; Thünemann, A F
2017-12-01
Data correction is probably the least favourite activity amongst users experimenting with small-angle X-ray scattering: if it is not done sufficiently well, this may become evident only during the data analysis stage, necessitating the repetition of the data corrections from scratch. A recommended comprehensive sequence of elementary data correction steps is presented here to alleviate the difficulties associated with data correction, both in the laboratory and at the synchrotron. When applied in the proposed order to the raw signals, the resulting absolute scattering cross section will provide a high degree of accuracy for a very wide range of samples, with its values accompanied by uncertainty estimates. The method can be applied without modification to any pinhole-collimated instruments with photon-counting direct-detection area detectors.
Coppola, R.; Fiori, F.; Little, E. A.; Magnani, M.
1997-06-01
Results are presented of a small-angle neutron scattering (SANS) study on two 10-13% Cr martensitic stainless steels of interest for nuclear applications, viz. DIN 1.4914 (MANET specification, for fusion reactors) and AISI 410. The investigation has focussed principally on microstructural effects associated with the differences in chromium content between the two alloys. The size distribution functions determined from nuclear and magnetic SANS components for the two steels given identical heat treatments are in accord with an interpretation based on the presence of ˜ 1 nm size CCr aggregates in the microstructure. Much larger (˜ 10 nm) scattering inhomogeneities with different magnetic contrast are also present and tentatively identified as carbides.
International Nuclear Information System (INIS)
Foster, L. John R.; Knott, Robert; Sanguanchaipaiwong, Vorapat; Holden, Peter J.
2006-01-01
Polyhydroxyalkanoates have attracted attention as biodegradable alternatives to conventional thermoplastics and as biomaterials. Through modification of their biosynthesis using Pseudomonas oleovorans, we have manipulated the material properties of these biopolyesters and produced a natural-synthetic hybrid copolymer of polyhydroxyoctanoate-block-diethylene glycol (PHO-b-DEG). A mixture of PHO and PHO-DEG were solvent cast from analytical grade chloroform and analysed using small-angle neutron scattering. A scattering pattern, easily distinguished above the background, was displayed by the films with a diffraction ring at q∼0.12 A -1 . This narrow ring of intensity is suggestive of a highly ordered system. Analysis of the diffraction pattern supported this concept and showed a d-spacing of approximately 50 A. In addition, conformation of the hybrid polymer chains can be manipulated to support their self-assembly into ordered microporous films
Limitation of the Mellin transform for small angle scattering by nearly spherical particles
International Nuclear Information System (INIS)
Melone, S.; Puliti, P.
1983-01-01
An analysis of the limit of validity of the Mellin transform when applied to small angle scattering curves produced by nearly spherical particles, i.e. by ellipsoids of semi-axes, a, a, va, was performed. The width of the assumed Gaussian distribution for the v values was used as a parameter. When this width tends to zero the inaccuracy of the Mellin transform vanishes as expected. However the inaccuracy becomes appreciable for large values of the width. In spite of this, the total volume fraction and the average radius of the scattering particles is also obtained by the Mellin transform with very high accuracy for large values of the width of the Gaussian distribution. (orig.)
Small angle x-ray scattering as a potential tool for cancer diagnosis
International Nuclear Information System (INIS)
Kitchen, M.; Siu, K.K.W.; Lewis, R.A.
2003-01-01
Full text: The diagnostic potential of Small Angle X-ray Scattering (SAXS) patterns has recently been investigated for malignant breast tissues. The demonstrated systematic differences in the scattering signatures of malignant, benign and normal breast tissue specimens are believed to arise from the changes in the fibrous proteins making up the extracellular matrix (ECM) with the disease progression. The technique may also have the potential to aid in the diagnosis of gliomas, a highly aggressive type of brain tumour. Although complex and difficult to interpret, SAXS data from malignant tissues may prove to be a more effective classification tool than conventional histology techniques. Here we present the methodology of the technique, as applied to breast cancer and brain tumour specimens to date, and some directions for future investigations. We also present a novel analysis method, which employs wavelet decomposition and a naive Bayesian classifier, as a potential semi-automated classification tool
Small angle neutron scattering study on star di-block copolymers
International Nuclear Information System (INIS)
Ertugrul, O.
2006-01-01
Determining structural properties, phase transitions and stability of polymer mixtures is very important to produce new materials with desired and interesting properties. Small Angle Neutron Scattering Technique (SANS) has been one of the most powerful and intensely used methods for the characterization of polymers for last decades, m this study, we use a model based on Gaussian Random Phase Approximation (RPA) to describe Star Di-block Copolymers (SDC) mixtures with homo-polymers. We could able to predict the miscibility and phase transitions of the various mixtures along with their structure factors, producing a thermodynamic picture of the system. Also the results suggest that scattering intensity will be dictated by the structure factor of the core or shell parts of star polymer only, which depends on the homo-polymer type of the mixture
Electromagnetic imaging of multiple-scattering small objects: non-iterative analytical approach
International Nuclear Information System (INIS)
Chen, X; Zhong, Y
2008-01-01
Multiple signal classification (MUSIC) imaging method and the least squares method are applied to solve the electromagnetic inverse scattering problem of determining the locations and polarization tensors of a collection of small objects embedded in a known background medium. Based on the analysis of induced electric and magnetic dipoles, the proposed MUSIC method is able to deal with some special scenarios, due to the shapes and materials of objects, to which the standard MUSIC doesn't apply. After the locations of objects are obtained, the nonlinear inverse problem of determining the polarization tensors of objects accounting for multiple scattering between objects is solved by a non-iterative analytical approach based on the least squares method
Branch Point Withdrawal in Elongational Startup Flow by Time-Resolved Small Angle Neutron Scattering
Ruocco, N.; Auhl, D.; Bailly, C.; Lindner, P.; Pyckhout-Hintzen, W.; Wischnewski, A.; Leal, L. G.; Hadjichristidis, Nikolaos; Richter, D.
2016-01-01
We present a small angle neutron scattering (SANS) investigation of a blend composed of a dendritic polymer and a linear matrix with comparable viscosity in start-up of an elongational flow at Tg + 50. The two-generation dendritic polymer is diluted to 10% by weight in a matrix of a long well-entangled linear chains. Both components consist of mainly 1,4-cis-polyisoprene but differ in isotopic composition. The resulting scattering contrast is sufficiently high to permit time-resolved measurements of the system structure factor during the start-up phase and to follow the retraction processes involving the inner sections of the branched polymer in the nonlinear deformation response. The outer branches and the linear matrix, on the contrary, are in the linear deformation regime. The linear matrix dominates the rheological signature of the blend and the influence of the branched component can barely be detected. However, the neutron scattering intensity is predominantly that of the (branched) minority component so that its dynamics is clearly evident. In the present paper, we use the neutron scattering data to validate the branch point withdrawal process, which could not be unambiguously discerned from rheological measurements in this blend. The maximal tube stretch that the inner branches experience, before the relaxed outer arm material is incorporated into the tube is determined. The in situ scattering experiments demonstrate for the first time the leveling-off of the strain as the result of branch point withdrawal and chain retraction directly on the molecular level. We conclude that branch point motion in the mixture of architecturally complex polymers occurs earlier than would be expected in a purely branched system, presumably due to the different topological environment that the linear matrix presents to the hierarchically deep-buried tube sections. © 2016 American Chemical Society.
Branch Point Withdrawal in Elongational Startup Flow by Time-Resolved Small Angle Neutron Scattering
Ruocco, N.
2016-05-27
We present a small angle neutron scattering (SANS) investigation of a blend composed of a dendritic polymer and a linear matrix with comparable viscosity in start-up of an elongational flow at Tg + 50. The two-generation dendritic polymer is diluted to 10% by weight in a matrix of a long well-entangled linear chains. Both components consist of mainly 1,4-cis-polyisoprene but differ in isotopic composition. The resulting scattering contrast is sufficiently high to permit time-resolved measurements of the system structure factor during the start-up phase and to follow the retraction processes involving the inner sections of the branched polymer in the nonlinear deformation response. The outer branches and the linear matrix, on the contrary, are in the linear deformation regime. The linear matrix dominates the rheological signature of the blend and the influence of the branched component can barely be detected. However, the neutron scattering intensity is predominantly that of the (branched) minority component so that its dynamics is clearly evident. In the present paper, we use the neutron scattering data to validate the branch point withdrawal process, which could not be unambiguously discerned from rheological measurements in this blend. The maximal tube stretch that the inner branches experience, before the relaxed outer arm material is incorporated into the tube is determined. The in situ scattering experiments demonstrate for the first time the leveling-off of the strain as the result of branch point withdrawal and chain retraction directly on the molecular level. We conclude that branch point motion in the mixture of architecturally complex polymers occurs earlier than would be expected in a purely branched system, presumably due to the different topological environment that the linear matrix presents to the hierarchically deep-buried tube sections. © 2016 American Chemical Society.
Amos, N.; Block, M.M.; Bobbink, G.J.; Botje, M.A.J.; Favart, D.; Leroy, C.; Linde, F.; Lipnik, P.; Matheys, J-P.; Miller, D.
1985-01-01
Antiproton-proton and proton-proton small-angle elastic scattering was measured for centre-of-mass energies at the CERN Intersectung Storage Rings. In addition, proton-proton elastic scattering was measured at . Using the optical theorem, total cross sections are obtained with an accuracy of about
Investigations of time resolved x-ray wide-angle scattering and x-ray small-angle scattering at DESY
International Nuclear Information System (INIS)
Zachmann, H.G.; Gehrke, R.; Prieske, W.; Riekel, C.
1985-01-01
Instrumentation is described for the simultaneous wide-angle and small-angle x-ray scattering. The method was applied to the study of the isothermal crystallization of polyethylene terephthalates. In agreement with the classical theories of crystallization, the data showed that the density difference between the crystals and the non-crystalline regions does not change with time. The mechanisms of melting, recrystallization, and crystal thickening were investigated by small-angle x-ray scattering with stepwise changes and continuous changes of temperature using polyethylene terephthalate
International Nuclear Information System (INIS)
Schoenborn, B.P.; Wise, D.S.; Schneider, D.K.
1983-01-01
Facilities for small angle x-ray and neutron scattering are described, with emphasis on the characterization of the primary beam of the neutron instrument and the spectrometer control logic of the synchrotron instrument
Resummations in QCD hard-scattering at large and small x
Kidonakis, Nikolaos; Stephens, Philip
2008-01-01
We discuss different resummations of large logarithms that arise in hard-scattering cross sections of quarks and gluons in regions of large and small x. The large-x logarithms are typically dominant near threshold for the production of a specified final state. These soft and collinear gluon corrections produce large enhancements of the cross section for many processes, notably top quark and Higgs production, and typically the higher-order corrections reduce the factorization and renormalization scale dependence of the cross section. The small-x logarithms are dominant in the regime where the momentum transfer of the hard sub-process is much smaller than the total collision energy. These logarithms are important to describe multijet final states in deep inelastic scattering and hadron colliders, and in the study of parton distribution functions. The resummations at small and large x are linked by the eikonal approximation and are dominated by soft gluon anomalous dimensions. We will review their role in both c...
Small-angle scattering at a pulsed neutron source: comparison with a steady-state reactor
Energy Technology Data Exchange (ETDEWEB)
Borso, C S; Carpenter, J M; Williamson, F S; Holmblad, G L; Mueller, M H; Faber, J Jr; Epperson, J E; Danyluk, S S [Argonne National Lab., IL (USA)
1982-08-01
A time-of-flight small-angle diffractometer employing seven tapered collimator elements and a two-dimensional gas proportional counter was successfully utilized to collect small-angle scattering data from a solution sample of the lipid salt cetylpyridinium chloride, C/sub 21/H/sub 38/N/sup +/.Cl/sup -/, at the Argonne National Laboratory prototype pulsed spallation neutron source, ZING-P'. Comparison of the small-angle scattering observed from the same compound at the University of Missouri Research Reactor corroborated the ZING-P' results. The results are used to compare the neutron flux available from the ZING-P' source relative to the well characterized University of Missouri source. Calculations based on experimentally determined parameters indicated the time-averaged rate of detected neutrons at the ZING-P' pulsed spallation source to have been at least 33% higher than the steady-state count rate from the same sample. Differences between time-of-flight techniques and conventional steady-state techniques are discussed.
Monomeric Amyloid Beta Peptide in Hexafluoroisopropanol Detected by Small Angle Neutron Scattering.
Directory of Open Access Journals (Sweden)
Bo Zhang-Haagen
Full Text Available Small proteins like amyloid beta (Aβ monomers are related to neurodegenerative disorders by aggregation to insoluble fibrils. Small angle neutron scattering (SANS is a nondestructive method to observe the aggregation process in solution. We show that SANS is able to resolve monomers of small molecular weight like Aβ for aggregation studies. We examine Aβ monomers after prolonged storing in d-hexafluoroisopropanol (dHFIP by using SANS and dynamic light scattering (DLS. We determined the radius of gyration from SANS as 1.0±0.1 nm for Aβ1-40 and 1.6±0.1 nm for Aβ1-42 in agreement with 3D NMR structures in similar solvents suggesting a solvent surface layer with 5% increased density. After initial dissolution in dHFIP Aβ aggregates sediment with a major component of pure monomers showing a hydrodynamic radius of 1.8±0.3 nm for Aβ1-40 and 3.2±0.4 nm for Aβ1-42 including a surface layer of dHFIP solvent molecules.
International Nuclear Information System (INIS)
Blazek, Jaroslav; Gilbert, Elliot Paul
2009-01-01
Full text: The digestion of starch has been the subject of many investigations, mostly involving in vitro measurement of the susceptibility of starches to attack by different enzymes, rather than measuring actual digestibility in vivo. The rate and extent of amylolytic hydrolysis of granular starches is known to vary according to botanical origin. Granule characteristics considered to influence susceptibility to attack by alpha-amylase include crystallinity, granule size and available specific surface, amylose content, porosity, structural inhomogeneities and degree of integrity. Most in-vitro studies of granular starch digestion have been limited to samples for which aliquots have been removed from the reaction mixture at various time intervals and freeze-dried to be subsequently characterized using a range of techniques. It remains unclear whether sample preparation creates artefacts in the samples. In this study, we have studied the kinetics of starch digestion of several commercial granular starches by time-resolved small-angle neutron scattering using an in-situ digestion chamber allowing, for the first time, to follow structural changes of starch in the course of digestion directly in the digestion mixture. Additionally, samples before and after digestion were studied by x-ray diffraction, small-angle x-ray scattering, differential scanning calorimetry and microscopy. Microscopy revealed that studied starches, which varied in their amylose content and digestion kinetics, followed different modes of attack The multidisciplinary approach allowed the nanostructural changes detected by small-angle scattering in the course of enzymic breakdown to be correlated with changes in crystallinity and functional properties.
Small-angle scattering studies of the fully hydrated phospholipid DPPC
Energy Technology Data Exchange (ETDEWEB)
Mason, P.C.; Gaulin, B.D. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (CANADA); Epand, R.M. [Department of Biochemistry, McMaster University, Hamilton, Ontario, L8N 3Z5 (CANADA); Wignall, G.D.; Lin, J.S. [Center for Small-Angle Scattering Research, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
1999-01-01
Small-angle neutron and x-ray scattering studies have been carried out on fully hydrated dipalmitoylphosphatidylcholine (DPPC) multilamellar vesicles. This system is known to exhibit two distinct ripple (P{sub {beta}{sup {prime}}}) phases, which depend on sample history, at temperatures intermediate to its high-temperature liquid crystalline (L{sub {alpha}}), phase, and its low-temperature gel (L{sub {beta}{sup {prime}}}), phase. On cooling from the L{sub {alpha}} phase, the P{sub {beta}{sup {prime}}} phase displays a complex multipeak diffraction pattern that differs significantly from the diffraction pattern seen in the P{sub {beta}{sup {prime}}} phase obtained on warming from the L{sub {beta}{sup {prime}}} phase. Examining the P{sub {beta}{sup {prime}}} phase on cooling using small-angle neutron scattering and x-ray diffraction techniques leads to the conclusion that this phase is characterized by a long wavelength ripple ({lambda}{sub r}{approximately}330thinsp{Angstrom}) and a highly monoclinic unit cell ({gamma}{approximately}125{degree}). As the P{sub {beta}{sup {prime}}} phase is traversed in temperature, the ripple wavelength changes significantly while the monoclinicity remains unchanged. Ripples from the P{sub {beta}{sup {prime}}} phase are seen to persist into the L{sub {beta}{sup {prime}}} phase on cooling, leading to increased small-angle scattering characteristic of a disordered stacking of the lamellae. {copyright} {ital 1999} {ital The American Physical Society}
International Nuclear Information System (INIS)
Leymarie, E.
2002-11-01
In this thesis we study the theoretical and experimental aspects of Contrast Variation by Nuclear Polarization (CVNP) applied to small-angle neutron scattering. The basics of neutron scattering theory is developed by highlighting the origin of the CVNP method: the strong spin dependence of thermal neutron scattering, especially on protons. We also present the principles of NMR with a special attention on the method of dynamic nuclear polarization by the solid effect which makes it possible to control the proton polarization and therefore the contrast for neutron scattering. We present a theoretical study of the CVNP method called static which supposes that the nuclear polarization is homogeneous in the sample and constant during the experiment. We show that it allows one to obtain partial structure functions of systems with multiple components, by carrying out several acquisitions with different polarizations on a single sample. For this purpose, we tested a simple device to stabilize the nuclear polarization. We describe finally a new application of the CVNP method called dynamic. In a solution of deuterated glycerol-water containing a small concentration of paramagnetic centres, we showed the existence of domains of polarized protons at the onset of dynamic polarization. This reinforces considerably the coherent scattering of paramagnetic centres. We describe the theoretical reasons explaining the appearance of these domains of polarization, as well as the various techniques used to observe them by neutron scattering. (author)
Small angle neutron scattering study of metallic alloys by a double crystal device
International Nuclear Information System (INIS)
Cser, L.; Kovacs, I.; Kroo, N.; Zsigmond, Gy.
1982-06-01
A double crystal small angle neutron scattering (SANS) device was built and a simple method for measuring the integrated SANS intensity was developed. The device and the method were tested and the possibility of future applications was demonstrated by measurements on different samples. The test measurements were performed on iron and teflon slabs of different thickness. On Fe-B metallic glasses a SANS intensity originating mainly from the multiple magnetic refraction at domain boundaries was observed. A very weak SANS intensity was found on turbine blades. The integrated SANS intensity was shown to correlate with the running time of the blades. Similar measurements were performed on artificially deformed steel samples. (author)
International Nuclear Information System (INIS)
Maitland, C.F.; Buckley, C.E.; O'Connor, B.H.; Rowles, M.R.; Hart, R.D.; Gilbert, E.P.; Connolly, J.
2005-01-01
Full text: Rowles and O'Connor optimised the compressive strength of a geopolymer produced by sodium silicate-activation of metakaolinite, and found that this material may have a greater compressive strength than ordinary Portland cement. It has been observed that similar metakaolin-based geopolymers have a multiscale structure that consists of partially dissolved metakaolinite embedded in a nanoporous matrix. The characteristics of the nanostructure within this matrix influence the physical properties of the geopolymer. An investigation, using small-angle neutron scattering and imaging techniques, into how the matrix nanostructure varies with chemical composition of the starting material has been undertaken. The results of this investigation will be reported. (authors)
Cylindrical aggregates of chlorophylls studied by small-angle neutron scatter
Energy Technology Data Exchange (ETDEWEB)
Worcester, D.L. [Univ. of Missouri, Columbus, MO (United States); Katz, J.J. [Argonne National Laboratory, IL (United States)
1994-12-31
Neutron small-angle scattering has demonstrated tubular chlorophyll aggregates formed by self-assembly of a variety of chlorophyll types in nonpolar solvents. The size and other properties of the tubular aggregates can be accounted for by stereochemical properties of the chlorophyll molecules. Features of some of the structures are remarkably similar to light harvesting chlorophyll complexes in vivo, particularly for photosynthetic bacteria. These nanotube chlorophyll structures may have applications as light harvesting biomaterials where efficient energy transfer occurs from an excited state which is highly delocalized.
Small angle neutron scattering study on a phase separation in a 3-component microemulsion system
International Nuclear Information System (INIS)
Seto, Hideki; Yokoi, Eiji; Komura, Shigehiro; Schwahn, Dietmar; Mortensen, Kell; Suzuki, Junichi; Funahashi, Satoru; Ito, Yuji.
1993-01-01
The mixture of three components, water, n-decane and 2-ethylhexylsulfosuccinate (AOT), is a well-known system that forms a 'water-in-oil' microemulsion at room temperature and decomposes with increasing temperature, thereby being associated with a critical phenomenon. Experimental results in previous literature, indicate that the phenomenon is interpreted to be that of the 3D-Ising, but we obtained the meanfield behavior of the susceptibility at 'near-critical region' by a small angle neutron scattering. The observed spinodal and binodal points were well explained assuming the van der Waals free energy expression. (author)
Electromagnetic scattering by a polydispersion of small charged cosmic dust particles
Directory of Open Access Journals (Sweden)
M. Kocifaj
2011-09-01
Full Text Available Some recent studies on extended red emissions suggest the presence of very small dust particles in the Universe. The sizes of these particles vary from 1 nm to some tens of nanometers, thus situating them deeply in the Rayleigh region if computations are made for visible or near infrared. The optical response of such particles can be a function of the surface charge. In this study we analyse the effect of surface electric potential on the total optical thickness and scattering phase function of the cosmic dust particles. The results are compared with those obtained for electrically neutral dust.
International Nuclear Information System (INIS)
Neskovic, N.; Ciric, D.; Perovic, B.
1982-01-01
The survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces is considered. The model is based on the momentum approximation. The projectiles are K + ions and the target is the (001)Ni+K surface. The incident energy is 100 eV and the incident angle 5 0 . The interaction potential of the projectile and the target consists of the Born-Mayer, the dipole and the image charge potentials. The transition probability function corresponds to the resonant electron transition to the 4s projectile energy level. (orig.)
Structure investigations on Portland cement paste by small angle neutron scattering
International Nuclear Information System (INIS)
Dragolici, C.A.; Lin, A.
2004-01-01
Hydrated Portland cement is a very complex material. Cement paste consists of many crystalline and non-crystalline phases in various ranges of sizes (μm and nm scale). The crystalline phases are embedded in amorphous phases of hydration products. We investigated the structural changes of hydrating phases in a time interval up to 18 days, at Budapest Neutron Center's SANS spectrometer. The small angle neutron scattering of Portland cements prepared with a various water-to-cement ratios, gave us information about the microstructure changes in the material. Fractals were a suitable way for structure modelling. Some comments regarding the opportunity of using the most common models are pointed out. (authors)
Enhancement of graphic user interface data acquisition of small angle neutron scattering
International Nuclear Information System (INIS)
Abd Aziz Muhammad; Abd Jalil Abd Hamid
2004-01-01
This paper discusses the activities of the development of data acquisition software for PC, which capable of controlling instrument via IEEE-488 and graphic visualization for small angle neutron scattering (SANS) runs in DOS mode. With the help of outstanding free ware graphic library for DOS, this software has enhanced the efficiency of graphic visualization for SANSLab data acquisition. Featuring easy-to-use graphical user interface (GUI) and several other built-in tools for convenience, this software can be manipulated with the mouse or the keyboard. This software can be converted into an inexpensive data acquisition system for SANS. (Author)
Simulation of small-angle scattering patterns using a CPU-efficient algorithm
Anitas, E. M.
2017-12-01
Small-angle scattering (of neutrons, x-ray or light; SAS) is a well-established experimental technique for structural analysis of disordered systems at nano and micro scales. For complex systems, such as super-molecular assemblies or protein molecules, analytic solutions of SAS intensity are generally not available. Thus, a frequent approach to simulate the corresponding patterns is to use a CPU-efficient version of the Debye formula. For this purpose, in this paper we implement the well-known DALAI algorithm in Mathematica software. We present calculations for a series of 2D Sierpinski gaskets and respectively of pentaflakes, obtained from chaos game representation.
Integrative structural modeling with small angle X-ray scattering profiles
Directory of Open Access Journals (Sweden)
Schneidman-Duhovny Dina
2012-07-01
Full Text Available Abstract Recent technological advances enabled high-throughput collection of Small Angle X-ray Scattering (SAXS profiles of biological macromolecules. Thus, computational methods for integrating SAXS profiles into structural modeling are needed more than ever. Here, we review specifically the use of SAXS profiles for the structural modeling of proteins, nucleic acids, and their complexes. First, the approaches for computing theoretical SAXS profiles from structures are presented. Second, computational methods for predicting protein structures, dynamics of proteins in solution, and assembly structures are covered. Third, we discuss the use of SAXS profiles in integrative structure modeling approaches that depend simultaneously on several data types.
The application of small-angle neutron scattering to the study of mass transfer in clays
International Nuclear Information System (INIS)
Allen, A.J.; Baston, A.H.; Bourke, P.J.; Jefferies, N.L.
1990-01-01
An extensive study using small angle neutron scattering (SANS) has been made of the pore structures in London Clay and in Ca-montmorillonite. Using SANS contrast variation techniques, the accessibilities of the pores to D 2 O by diffusion and permeation have been studied. Characterisation of the accessibility to different parts of the pore structure is intended to provide input data for models of radionuclide transport through clay geological barriers, and to improve interpretation of laboratory experiments that measure sorption of radionuclides on clays. (author)
Study of pore growth in glassy carbon using small angle x-ray scattering
International Nuclear Information System (INIS)
Hoyt, J.
1982-07-01
Small-angle x-ray scattering was used to study the average pore size in glass-like carbon as a function of both heat-treatment time and heat-treatment temperature. A pore-growth model based on graphitization processes is presented. The simple mechanism shows that the change in the average radius of gyration with time is related to the total number of pores as a function of time, which in turn depends on the irreversible thermal-expansion phenomenon. The results of this study are inconsistent with a vacancy-migration pore-growth mechanism proposed earlier
Q resolution calculation of small angle neutron scattering spectrometer and analysis of form factor
International Nuclear Information System (INIS)
Chen Liang; Peng Mei; Wang Yan; Sun Liangwei; Chen Bo
2011-01-01
The calculational methods of Small Angle Neutron Scattering (SANS) spectrometer Q resolution function and its correlative Q standard difference were introduced. The effects of Q standard difference were analysed with the geometry lay out of spectrometer and the spread of neutron wavelength. The one dimension Q resolution Gaussian function were analysed. The form factor curve of ideal solid sphere and two different instrument arrangement parameter was convoluted respectively and the different smearing curve of form factor was obtained. The combination of using the Q resolution function to more accurately analysis SANS data. (authors)
The polarized neutron small-angle scattering instrument at BENSC Berlin
International Nuclear Information System (INIS)
Keller, T.; Krist, T.; Danzig, A.; Keiderling, U.; Mezei, F.; Wiedenmann, A.
2000-01-01
A polarized neutron beam has been installed at the small-angle neutron-scattering instrument V4 at BENSC Berlin. The main component of this new option is a 1.8 m long cavity transmission polarizer. The advantages of this device compared to the conventional bender polarizers are: (i) high transmission (35% of unpolarized beam at λ=6 A); (ii) the polarization is better than 93% in the wavelength band 4 A 3 O 4 particles embedded in a glass matrix) are presented and compared to a measurement with unpolarized neutrons
Small-angle neutron scattering study of high-pressure sintered detonation nanodiamonds
Energy Technology Data Exchange (ETDEWEB)
Kidalov, S. V.; Shakhov, F. M., E-mail: fedor.shakhov@mail.ioffe.ru [Ioffe Physical-Technical Institute of the Russian Academy of Sciences (Russian Federation); Lebedev, V. T.; Orlova, D. N.; Grushko, Yu. S. [Russian Academy of Sciences, Konstantinov St. Petersburg Nuclear Physics Institute (Russian Federation)
2011-12-15
The structure of detonation diamonds sintered at a high pressure (7 GPa) and temperatures of 1200-1700 Degree-Sign C has been investigated by small-angle neutron scattering. It is shown that sintering leads to an increase in the particle size from 6 to 30 nm and established that this increase is due to the chainlike oriented attachment of particles. This study supplements the oriented-attachment model, which was suggested based on the X-ray diffraction spectra of detonation nanodiamonds (DNDs) sintered under the same conditions.
Directory of Open Access Journals (Sweden)
L. A. Bulavin
2015-07-01
Full Text Available The paper presents the results of the structural study of various types of the water-detonation nanodiamond liquid systems, which are obtained by small-angle scattering of thermal neutrons. It was shown that in the mass fraction range (0.3 - 1.8 % the experimental spectra are well described by a two-level model of unified exponential/power-law approach. The resulting structural parameters allowed us to estimate the aggregation number in the studied systems. Sizes of the nanodiamond particles and their clusters are found as well as the fractal dimension of the latter.
International Nuclear Information System (INIS)
Bulavin, L.A.; Tomchuk, O.V.; Avdeev, M.V.
2015-01-01
The paper presents the results of the structural study of various types of the water-detonation nanodiamond liquid systems, which are obtained by small-angle scattering of thermal neutrons. It was shown that in the mass fraction range (0.3/1.8) % the experimental spectra are well described by a two-level model of unified exponential/power-law approach. The resulting structural parameters allowed us to estimate the aggregation number in the studied systems. Sizes of the nanodiamond particles and their clusters are found as well as the fractal dimension of the latter
Anomalous small-angle scattering as a way to solve the Babinet principle problem
International Nuclear Information System (INIS)
Boiko, M. E.; Sharkov, M. D.; Boiko, A. M.; Bobyl, A. V.
2013-01-01
X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different monochromatic X-ray beams at different wavelengths near the absorption edges is performed to solve the Babinet principle problem. The sizes of clusters containing atoms determined by the method of XAS were defined in SAXS experiments. In contrast to differential X-ray porosimetry, anomalous SAXS makes it possible to determine sizes of clusters of different atomic compositions
Anomalous small-angle scattering as a way to solve the Babinet principle problem
Energy Technology Data Exchange (ETDEWEB)
Boiko, M. E., E-mail: m.e.boiko@mail.ioffe.ru; Sharkov, M. D.; Boiko, A. M.; Bobyl, A. V. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)
2013-12-15
X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different monochromatic X-ray beams at different wavelengths near the absorption edges is performed to solve the Babinet principle problem. The sizes of clusters containing atoms determined by the method of XAS were defined in SAXS experiments. In contrast to differential X-ray porosimetry, anomalous SAXS makes it possible to determine sizes of clusters of different atomic compositions.
Anomalous small-angle scattering as a way to solve the Babinet principle problem
Boiko, M. E.; Sharkov, M. D.; Boiko, A. M.; Bobyl, A. V.
2013-12-01
X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different monochromatic X-ray beams at different wavelengths near the absorption edges is performed to solve the Babinet principle problem. The sizes of clusters containing atoms determined by the method of XAS were defined in SAXS experiments. In contrast to differential X-ray porosimetry, anomalous SAXS makes it possible to determine sizes of clusters of different atomic compositions.
International Nuclear Information System (INIS)
Kartavtsev, O.I.; Malykh, A.V.; Sofianos, S.A.
2008-01-01
The universal three-body dynamics in ultracold binary gases confined to one-dimensional motion is studied. The three-body binding energies and the (2+1)-scattering lengths are calculated for two identical particles of mass m and a different one of mass m 1 , between which interactions are described in the low-energy limit by zero-range potentials. The critical values of the mass ratio m/m 1 , at which the three-body states arise and the (2+1)-scattering length equals zero, are determined both for zero and infinite interaction strength λ 1 of the identical particles. A number of exact results are enlisted and asymptotic dependences both for m/m 1 → infinity and λ 1 → -infinity are derived. Combining the numerical and analytical results, a schematic diagram showing the number of the three-body bound states and the sign of the (2+1)-scattering length in the plane of the mass ratio and interaction-strength ratio is deduced. The results provide a description of the homogeneous and mixed phases of atoms and molecules in dilute binary quantum gases
Recent developments in X-ray and neutron small-angle scattering instrumentation and data analysis
International Nuclear Information System (INIS)
Schelten, J.
1978-01-01
The developments in instrumentation and data analysis that have occurred in the field of small-angle X-ray and neutron scattering since 1973 are reviewed. For X-rays, the cone camera collimation was invented, synchrotrons and storage rings were demonstrated to be intense sources of X-radiation, and one- and two-dimensional position-sensitive detectors were interfaced to cameras with both point and line collimation. For neutrons, the collimators and detectors on the Juelich and Grenoble machines were improved, new D11-type instruments were built or are under construction at several sites, double-crystal instruments were set up, and various new machines have been proposed. Significant progress in data analysis and evaluation has been made through application of mathematical techniques such as the use of spline functions, error minimization with constraints, and linear programming. Several special experiments, unusual in respect to the anisotropy of the scattering pattern, gravitational effects, moving scatterers, and dynamic fast time slicing, are discussed. (Auth.)
Reflective small angle electron scattering to characterize nanostructures on opaque substrates
Friedman, Lawrence H.; Wu, Wen-Li; Fu, Wei-En; Chien, Yunsan
2017-09-01
Feature sizes in integrated circuits (ICs) are often at the scale of 10 nm and are ever shrinking. ICs appearing in today's computers and hand held devices are perhaps the most prominent examples. These smaller feature sizes demand equivalent advances in fast and accurate dimensional metrology for both development and manufacturing. Techniques in use and continuing to be developed include X-ray based techniques, optical scattering, and of course the electron and scanning probe microscopy techniques. Each of these techniques has their advantages and limitations. Here, the use of small angle electron beam scattering measurements in a reflection mode (RSAES) to characterize the dimensions and the shape of nanostructures on flat and opaque substrates is demonstrated using both experimental and theoretical evidence. In RSAES, focused electrons are scattered at angles smaller than 1 ° with the assistance of electron optics typically used in transmission electron microscopy. A proof-of-concept experiment is combined with rigorous electron reflection simulations to demonstrate the efficiency and accuracy of RSAES as a method of non-destructive measurement of shapes of features less than 10 nm in size on flat and opaque substrates.
Assess the Intra-molecular Cavity in PAMAM Dendrimers by Small Angle Neutron Scattering
International Nuclear Information System (INIS)
Chen, Wei-Ren
2008-01-01
In this report, we present a contrast variation small angle neutron scattering (SANS) study of a series of neutral PAMAM dendrimer in aqueous solutions using three different generations (G4-6) at a concentration of about 10 mg/ml. Varying the solvent hydrogen-deuterium ratio, the scattering contributions from the water molecules and the constituent components of PAMAM dendrimer can be determined. Using an analytical model of the scattering cross section I(Q) incorporating the effect of water penetration, we have quantified the intra-molecular space of PAMAM dendrimer by evaluating the number of guest water molecules and we draw a direct comparison to computational predictions. As expected, the overall available internal cavity was seen to increase as a function of increasing dendrimer generation. However, the fraction of water accessible volume in the internal cavity of a dendrimer was found to remain invariant for the three generation PAMAM dendrimers studied in this report. We have also estimated the average water density inside a dendrimer, which is found to be higher than that of bulk water
International Nuclear Information System (INIS)
Rosenfeldt, S.; Dingenouts, N.; Poetschke, D.; Ballauff, M.; Berresheim, A.J.; Muellen, K.; Lindner, P.; Saalwaechter, K.
2005-01-01
The analysis of the spatial structure of a rigid polyphenylene dendrimer G4-M of fourth generation by small-angle neutron scattering (SANS) is presented. This dendrimer is composed of phenyl units and is therefore devoid of any flexible unit. The scattering intensity of dilute solutions of the dendrimer was measured by SANS at different contrast which was adjusted by mixtures of protonated and deuterated toluene. Hence, the method of contrast variation could be applied and the data yield the scattering function extrapolated to infinite contrast. The comparison of this data with simulations demonstrates that the scaffold of the dendrimer is rigid as expected from its chemical structure. The positions of the various units setting up consecutive shells of the dendrimer are relatively well localized and the entire structure cannot be modeled in terms of spherically symmetric models. No backfolding of the terminal groups can occur and the model calculations demonstrate that higher generations of this dendritic scaffold must exhibit a dense shell and a congestion of the terminal groups. This finding is directly corroborated by recent solid-state NMR data. All results show that the rigid dendrimer investigated here presents the first example for a dendritic structure whose segment density does not have its maximum at the center. Rigid scaffolds are therefore the only way to achieve the goal of a 'dense-shell' dendrimer whereas flexible scaffolds leads invariably to the 'dense-core' case
Energy Technology Data Exchange (ETDEWEB)
Hopkins, Alan R., E-mail: alan.r.hopkins@aero.org [Aerospace Corporation, Space Materials Lab, Micro/Nano Technology Dept, Polymers Section, M2/242, Los Angeles, CA 90009-2957 (United States); Tomczak, Sandra J. [AFRL/RZSM Materials Application Branch, Space and Missile Propulsion Division 10 East Saturn Blvd., Bldg. 8451, Edwards Air Force Base, CA 93524 (United States); Vij, Vandana [ERC. Inc., AFRL/PRSM, Edwards AFB, CA (United States); Jackson, Andrew J. [National Institute of Standards and Technology (NIST) Center for Neutron Research, 100 Bureau Drive, Stop 6102, Gaithersburg, MD 20899-6102 (United States)
2011-12-30
Nanocomposites of polyaniline nanofibers and polyimide were fabricated and studied using small angle neutron scattering (SANS). The immiscible nature of the conformationally dissimilar polyaniline nanofiber and polyimide host is established by a series of experiments involving neutron scattering. Based on these techniques, we conclude that the crystal structure of the polyimides is not disrupted, and that there is no mixing between the two components on a molecular level. The morphology of the conducting salt component was analyzed by SANS data and was treated by two common models: Debye-Bueche (D-B) and inverse power law (IPL). Due to deviations in the linear curve fitting over a large scattering range, neither the D-B nor the IPL model could be used to characterize the size and shape of all PANI-0.5-CSA (polyaniline camphor sulfonic acid doped polymer)/polyimide blend systems. At 1 and 2% concentration, the D-B model suggested salt domains between 20 and 70 A with fractal geometries implied by the IPL model. As salt concentrations increased to 5%, the structures were observed to change, but there is no simple structural model that provides a suitable basis for comparison.
Fractal Structures on Silica Aerogels Containing Titanium: A Small Angle Neutron Scattering Study
International Nuclear Information System (INIS)
Widya Sari; Dian Fitriyani; Abdul Aziz Mohamed; Noordin Ibrahim
2009-01-01
Full text: The fractal structure of silica aerogels containing titanium has been investigated by means of small-angle neutron scattering (SANS) technique. The SANS experiments were conducted using a 36 meter SANS BATAN spectrometer (SMARTer) in Serpong, Indonesia in the range of momentum transfer Q, 0.006 -1 ) < 0.3. The power-law for a fractal object scattering Q-D observed from all measured samples. The Fourier transform of pattern I(Q) a pair correlation model function was implemented in analyzing the structure factor from the power-law scattering profiles. The results are showing that the silica aerogels containing titanium has a mass fractal where its dimension DM is larger than the pure silica aerogels. The mass fractal dimension of silica aerogels containing titanium is relatively constant between 2.23 to 2.40 with the decrease of acid concentrations during a sol-gel process and formed a nanometer size of aggregate. Those fractal structures were simulated using a Delphi language and the results are presented in this paper. (author)
Calculation of accurate small angle X-ray scattering curves from coarse-grained protein models
Directory of Open Access Journals (Sweden)
Stovgaard Kasper
2010-08-01
Full Text Available Abstract Background Genome sequencing projects have expanded the gap between the amount of known protein sequences and structures. The limitations of current high resolution structure determination methods make it unlikely that this gap will disappear in the near future. Small angle X-ray scattering (SAXS is an established low resolution method for routinely determining the structure of proteins in solution. The purpose of this study is to develop a method for the efficient calculation of accurate SAXS curves from coarse-grained protein models. Such a method can for example be used to construct a likelihood function, which is paramount for structure determination based on statistical inference. Results We present a method for the efficient calculation of accurate SAXS curves based on the Debye formula and a set of scattering form factors for dummy atom representations of amino acids. Such a method avoids the computationally costly iteration over all atoms. We estimated the form factors using generated data from a set of high quality protein structures. No ad hoc scaling or correction factors are applied in the calculation of the curves. Two coarse-grained representations of protein structure were investigated; two scattering bodies per amino acid led to significantly better results than a single scattering body. Conclusion We show that the obtained point estimates allow the calculation of accurate SAXS curves from coarse-grained protein models. The resulting curves are on par with the current state-of-the-art program CRYSOL, which requires full atomic detail. Our method was also comparable to CRYSOL in recognizing native structures among native-like decoys. As a proof-of-concept, we combined the coarse-grained Debye calculation with a previously described probabilistic model of protein structure, TorusDBN. This resulted in a significant improvement in the decoy recognition performance. In conclusion, the presented method shows great promise for
Small-Angle Neutron Scattering Investigation of Growth Modifiers on Hydrate Crystal Surfaces
Sun, Thomas; Hutter, Jeffrey L.; Lin, M.; King, H. E., Jr.
1998-03-01
Hydrates are crystals consisting of small molecules enclathrated within an ice-like water cage. Suppression of their growth is important in the oil industry. The presence of small quantities of specific polymers during hydrate crystallization can induce a transition from an octahedral to planar growth habit. This symmetry breaking is surprising because of the suppression of two 111 planes relative to the other six crystallographically equivalent faces. To better understand the surface effects leading to this behavior, we have studied the surface adsorption of these growth-modifing polymers onto the hydrate crytals using SANS. The total hydrate surface area, as measured by Porod scattering, increases in the presence of the growth modifier, but, no significant increase in polymer concentration on the crystal surfaces is found. Implications for possible growth mechanisms will be discussed.
Protein folding and protein metallocluster studies using synchrotron small angler X-ray scattering
International Nuclear Information System (INIS)
Eliezer, D.
1994-06-01
Proteins, biological macromolecules composed of amino-acid building blocks, possess unique three dimensional shapes or conformations which are intimately related to their biological function. All of the information necessary to determine this conformation is stored in a protein's amino acid sequence. The problem of understanding the process by which nature maps protein amino-acid sequences to three-dimensional conformations is known as the protein folding problem, and is one of the central unsolved problems in biophysics today. The possible applications of a solution are broad, ranging from the elucidation of thousands of protein structures to the rational modification and design of protein-based drugs. The scattering of X-rays by matter has long been useful as a tool for the characterization of physical properties of materials, including biological samples. The high photon flux available at synchrotron X-ray sources allows for the measurement of scattering cross-sections of dilute and/or disordered samples. Such measurements do not yield the detailed geometrical information available from crystalline samples, but do allow for lower resolution studies of dynamical processes not observable in the crystalline state. The main focus of the work described here has been the study of the protein folding process using time-resolved small-angle x-ray scattering measurements. The original intention was to observe the decrease in overall size which must accompany the folding of a protein from an extended conformation to its compact native state. Although this process proved too fast for the current time-resolution of the technique, upper bounds were set on the probable compaction times of several small proteins. In addition, an interesting and unexpected process was detected, in which the folding protein passes through an intermediate state which shows a tendency to associate. This state is proposed to be a kinetic molten globule folding intermediate
Small-angle neutron scattering study of micropore collapse in amorphous solid water.
Mitterdorfer, Christian; Bauer, Marion; Youngs, Tristan G A; Bowron, Daniel T; Hill, Catherine R; Fraser, Helen J; Finney, John L; Loerting, Thomas
2014-08-14
Vapor-deposited amorphous solid water (ASW) is the most abundant solid molecular material in space, where it plays a direct role in both the formation of more complex chemical species and the aggregation of icy materials in the earliest stages of planet formation. Nevertheless, some of its low temperature physics such as the collapse of the micropore network upon heating are still far from being understood. Here we characterize the nature of the micropores and their collapse using neutron scattering of gram-quantities of D2O-ASW of internal surface areas up to 230 ± 10 m(2) g(-1) prepared at 77 K. The model-free interpretation of the small-angle scattering data suggests micropores, which remain stable up to 120-140 K and then experience a sudden collapse. The exact onset temperature to pore collapse depends on the type of flow conditions employed in the preparation of ASW and, thus, the specific surface area of the initial deposit, whereas the onset of crystallization to cubic ice is unaffected by the flow conditions. Analysis of the small-angle neutron scattering signal using the Guinier-Porod model suggests that a sudden transition from three-dimensional cylindrical pores with 15 Å radius of gyration to two-dimensional lamellae is the mechanism underlying the pore collapse. The rather high temperature of about 120-140 K of micropore collapse and the 3D-to-2D type of the transition unraveled in this study have implications for our understanding of the processing and evolution of ices in various astrophysical environments.
Spin-Echo Small Angle Neutron Scattering analysis of liposomes and bacteria
van Heijkamp, Léon F.; Sevcenco, Ana-Maria; Abou, Diane; van Luik, Remko; Krijger, Gerard C.; Hagedoorn, Peter-Leon; de Schepper, Ignatz M.; Wolterbeek, Bert; Koning, Gerben A.; Bouwman, Wim G.
2010-10-01
Two types of liposomes, commonly used in drug delivery studies, and E. coli bacteria, all prepared in H2O, were resuspended in D2O and measured with Small Angle Spin-Echo Neutron Scattering (SESANS). Modeling was performed using correlation functions for solid spheres and hollow spheres. The signal strength and curve shape were more indicative of hollow particles, indicating that the H2O-D2O exchange occurred too fast to be observed with the available time resolution. Fitting the particle diameter and membrane thickness of the hollow sphere model to the data, gave results which were in good agreement with Dynamic Light Scattering (DLS) data and literature, showing as a proof-of-principle that SESANS is able to investigate such systems. SESANS may become a good alternative to conventional tritium studies or a tool with which to study intracellular vesicle transport phenomena, with possible in vivo applications. Calculations show that a substantial change in numbers of a mixed system of small and large biological particles should be observable. A possible application is the destruction by external means of great numbers of liposomes in the presence of tumor cells for triggered drug release in cancer treatment. Since SESANS is both non-invasive and non-destructive and can handle relatively thick samples, it could be a useful addition to more conventional techniques.
The current status of small-angle x-ray scattering beamline at Diamond Light Source
International Nuclear Information System (INIS)
Inoue, Katsuaki; Doutch, James; Terrill, Nick
2013-01-01
The small-angle X-ray scattering (SAXS) covers the major disciplines of biology, chemistry and physics delivering structural and dynamic information in nanoscience, mesoscopic architectures, supramolecular structures, and nucleation/growth of crystals. SAXS is also proving to be important in archaeological, environmental, and conservation sciences, and has further indicated its ability to span wide-ranging scientific disciplines. Thus, strong needs for SAXS studies are increasing significantly in a broad range of scientific fields year by year. Based on such a background, the demand for high throughput SAXS experiments is increasing. At the synchrotron facility, Diamond Light Source, one SAXS beamline, Non-crystalline diffraction I22 is now operational and highly automated throughput small-angle X-ray scattering (HATSAXS) beamline B21 is now under construction. I22 is the Undulator beamline and wide varieties of experiments, including time-resolved experiments are attempted. Based on the concept of HATSAXS, the key feature of B21 will focuses on the automation of end-station equipment. A automated sample changer has been purchased for solution SAXS measurements on biomolecules. A robotic-arm-type automated sample changer that is capable of handling several kinds of samples in material science is also being constructed. B21 is expected to successfully provide all users highly automated throughput measurements with the highest possible reliability and accuracy. Construction of this beamline will end in the second half of 2012, and will be open for users in the early summer of 2013 after commissioning. (author)
International Nuclear Information System (INIS)
Koizumi, Satoshi; Motokawa, Ryuhei; Iwase, Hiroki; Miyamoto, Nobuyoshi; Tanaka, Kazuhiro; Masui, Tomomi; Iida, You; Yue, Zhao; Chiba, Kaori; Kumada, Takayuki; Yamaguchi, Daisuke; Hashimoto, Takeji
2007-01-01
To address the question as to how small-angle scattering is effectively applied to the cell, i.e., a hierarchically ordered system comprising multi-components of macro and small molecules, the size of which ranges from 100 μm to several μm, we reconstructed SANS-J (pinhole small-angle neutron scattering spectrometer at research reactor JRR3, Tokai) to focusing and polarized neutron small-angle spectrometer (SANS-J-II), by employing focusing neutron lenses and high resolution photomultiplier. Consequently, an accessible minimum wave number q min was improved from 3x10 -3 A -1 to medium ultra-small angle scattering of 3x10 -4 A -1 . The focusing USANS method, thus developed, is crucial to fill the gap in wave number q between those covered by a double crystal method and by a conventional pin-hole method. (author)
International Nuclear Information System (INIS)
Van Hook, W.A.
2000-01-01
A research program examining the effects of pressure, isotope substitution and other variables on miscibility in polymer solvent systems is described. The techniques employed included phase equilibrium measurements and dynamic light scattering and small angle neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Tikhomirov, Victor V. [Belarusian State University, Institute for Nuclear Problems, Minsk (Belarus)
2017-07-15
A refined equation for channeling particle diffusion in transverse energy taking into consideration large-angle scattering by nuclei is suggested. This equation is reduced to the Sturm-Liouville problem, allowing one to reveal both the origin and the limitations of the dechanneling length notion. The values of the latter are evaluated for both positively and negatively charged particles of various energies. New features of the dechanneling dynamics of positively charged particles are also revealed. First, it is demonstrated that the dechanneling length notion is completely inapplicable for their nuclear dechanneling process. Second, the effective electron dechanneling length of positively charged particle varies more than twice converging to a constant asymptotic value only at the depth exceeding the latter. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Eremin, Roman A., E-mail: era@jinr.ru [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Kholmurodov, Kholmirzo T. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); International University “Dubna”, Dubna 141980 (Russian Federation); Petrenko, Viktor I. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Taras Shevchenko National University of Kyiv, Kyiv 03022 (Ukraine); Rosta, László [Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest H-1525 (Hungary); Grigoryeva, Natalia A. [Faculty of Physics, Saint-Petersburg State University, 198504 Saint-Petersburg (Russian Federation); Avdeev, Mikhail V. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)
2015-11-05
Highlights: • The model of the scattering particle for a reliable SANS analysis is proposed. • The structural parameters of saturated mono-carboxylic acids in solutions are obtained. • The differences in nematic transitions correlate to solvation peculiarities. - Abstract: The data of infrared spectroscopy (IR), molecular dynamics (MD) simulations and small-angle neutron scattering (SANS) have been combined to conclude about the nanoscale structural organization of organic non-polar solutions of saturated mono-carboxylic acids with different alkyl chain lengths for diluted solutions of saturated myristic (C14) and stearic (C18) acids in benzene and decalin. In particular, the degree of dimerization was found from the IR spectra. The structural anisotropy of the acids and their dimers was used in the treatment of the data of MD simulations to describe the solute–solvent interface in a cylindrical approximation and show its rather strong influence on SANS. The corresponding scattering length density profiles were used to fit the experimental SANS data comprising the information about the acid molecule isomerization. The SANS data from concentrated solutions showed a partial self-assembling of the acids within the nematic transition is different for two solvents due to lyophobic peculiarities.
International Nuclear Information System (INIS)
Berr, S.S.
1986-12-01
We have determined the structure of micelles formed in water by several classes of ionic surfactants under a variety of experimental conditions using small-angle neutron scattering (SANS) techniques. Contrast between the micelles and the solvent was achieved through either selective deuteration or fluorination of the surfactant, or through the use of D 2 O. Interpretation of SANS data was facilitated by the use of Hayter, Penfold, and Hansen's rescaled Mean Spherical Approximation theory to calculate the scattering due to interparticle interactions. We have devised a number of micelle models, both spherical and ellipsoidal, to account for the scattering due to single micelles. It was found that changing the solvent from H 2 O to D 2 O results in the formation of larger micelles due to changes in the solvent-surfactant hydrocarbon interactions. This solvent isotope effect increased as the length of the alkyl chain increased. The fractional micellar charge did not change with respect to isotopic composition of solvent. We found that alkyltrimethylammonium bromide surfactants form drier micelles than do the sodium alkyl sulfate surfactants of equal chain length. Also, all micelles studied were found to be dry near the critical micelle concentration (cmc) and to become increasingly wetter as the concentration increased. The increase in aggregation number with respect to the square root of surfactant concentration was found to be linear for all systems studied. 80 figs
A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion
Energy Technology Data Exchange (ETDEWEB)
Yagi, N; Ohta, N; Matsuo, T [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Tanaka, T; Terada, Y; Kamasaka, H; Kometani, T, E-mail: yagi@spring8.or.j [Ezaki Glico Co. Ltd., 4-6-5 Utajima, Nishiyodogawa-ku, Osaka 555-8502 (Japan)
2010-10-01
The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6{mu}m at BL40XU and 50{mu}m at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.
A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion
International Nuclear Information System (INIS)
Yagi, N; Ohta, N; Matsuo, T; Tanaka, T; Terada, Y; Kamasaka, H; Kometani, T
2010-01-01
The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6μm at BL40XU and 50μm at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.
Dahani, Mohamed; Barret, Laurie-Anne; Raynal, Simon; Jungas, Colette; Pernot, Pétra; Polidori, Ange; Bonneté, Françoise
2015-01-01
The structural and interactive properties of two novel hemifluorinated surfactants, F2H9-β-M and F4H5-β-M, the syntheses of which were based on the structure and hydrophobicity of the well known dodecyl-β-maltoside (DD-β-M), are described. The shape of their micellar assemblies was characterized by small-angle X-ray scattering and their intermicellar interactions in crystallizing conditions were measured by dynamic light scattering. Such information is essential for surfactant phase-diagram determination and membrane-protein crystallization. PMID:26144228
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...
Energy Technology Data Exchange (ETDEWEB)
Wells, Hannah C.; Sizeland, Katie H.; Kayed, Hanan R.; Haverkamp, Richard G., E-mail: r.haverkamp@massey.ac.nz [School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North 4442 (New Zealand); Kirby, Nigel; Hawley, Adrian; Mudie, Stephen T. [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)
2015-01-28
Type I collagen is the main structural component of skin, tendons, and skin products, such as leather. Understanding the mechanical performance of collagen fibrils is important for understanding the mechanical performance of the tissues that they make up, while the mechanical properties of bulk tissue are well characterized, less is known about the mechanical behavior of individual collagen fibrils. In this study, bovine pericardium is subjected to strain while small angle X-ray scattering (SAXS) patterns are recorded using synchrotron radiation. The change in d-spacing, which is a measure of fibril extension, and the change in fibril diameter are determined from SAXS. The tissue is strained 0.25 (25%) with a corresponding strain in the collagen fibrils of 0.045 observed. The ratio of collagen fibril width contraction to length extension, or the Poisson's ratio, is 2.1 ± 0.7 for a tissue strain from 0 to 0.25. This Poisson's ratio indicates that the volume of individual collagen fibrils decreases with increasing strain, which is quite unlike most engineering materials. This high Poisson's ratio of individual fibrils may contribute to high Poisson's ratio observed for tissues, contributing to some of the remarkable properties of collagen-based materials.
International Nuclear Information System (INIS)
Hjelm, R.P.; Wampler, W.; Gerspacher, M.
1996-01-01
We have been exploring the use of small-angle neutron scattering and the method of contrast variation to give a new look at a very old problem: reinforcement of elastomers by carbon black in durable rubber products. Carbon black has a hierarchy of structures consisting of particles covalently bound into aggregates, which in turn associate by weak interactions into agglomerates. We found that in one carbon black, HSA, the aggregates are rodlike, containing an average of 4-6 particles. The aggregates have an outer graphitic shell and an inner core of lower density carbon. The core is continuous throughout the carbon black aggregate. Contrast variation of swollen HSA-polyisoprene gels shows that the HSA is completely embedded in polyisoprene and that the agglomerates are formed predominantly by end on associations of the rodlike aggregates. The surface structure of the carbon black appears smooth over length scales above about 10 angstrom. Further studies using production carbon blacks suggest that these structural characteristics are generally present in commercial rubber composites
Ospinal-Jiménez, Mónica; Pozzo, Danilo C
2011-02-01
Small-angle X-ray (SAXS) and neutron (SANS) scattering is used to probe the structure of protein-surfactant complexes in solution and to correlate this information with their performance in gel electrophoresis. Proteins with sizes between 6.5 to 116 kDa are denatured with sodium alkyl sulfates (SC(x)S) of variable tail lengths. Several combinations of proteins and surfactants are analyzed to measure micelle radii, the distance between micelles, the extension of the complex, the radius of gyration, and the electrophoretic mobility. The structural characterization shows that most protein-surfactant complexes can be accurately described as pearl-necklace structures with spherical micelles. However, protein complexes with short surfactants (SC(8)S) bind with micelles that deviate significantly from spherical shape. Sodium decyl (SC(10)S) and dodecyl (SC(12)S, more commonly abbreviated as SDS) sulfates result in the best protein separations in standard gel electrophoresis. Particularly, SC(10)S shows higher resolutions for complexes of low molecular weight. The systematic characterization of alkyl sulfate surfactants demonstrates that changes in the chain architecture can significantly affect electrophoretic migration so that protein-surfactant structures could be optimized for high resolution protein separations.
Small-angle neutron scattering study of D2O-alcohol solutions
International Nuclear Information System (INIS)
D'Arrigo, G.
1990-01-01
Small-angle neutron scattering (SANS) measurements have been carried out on heavy water solutions of ethanol, isopropyl alcohol, n-propyl alcohol, t-butyl alcohol and butoxyethanol between 5 and 37 0 C at the concentrations where ultrasonic attenuation exhibits peak values. The wavevector dependence and the absolute intensity of the scattered intensities were analysed according to a microscopic model of the solutions in terms of aggregated complexes. The results indicate that at 25 0 C there exist either alcohol 'micelle-like' structures or alcohol-heavy water complexes which increase on going from the lower to higher alcohol solutions. As temperature increases from 25 to 37 0 C a higher aggregation is observed in butyl alcohol and butoxyethanol solutions. This behaviour is attributed to the demixing tendency of these systems at high temperatures. On going from 25 to 5 0 C the aggregation increases again. This trend is associated with the anomalous behaviour of the specific heat and ultrasonic attenuation of these systems. The occurrence of a low-temperature phase transition suggested by these anomalies is supported by our results. (author)
Neutron small-angle scattering study of phase decomposition in Au-Pt
International Nuclear Information System (INIS)
Singhal, S.P.; Herman, H.
1978-01-01
Isothermal decomposition of a Au-60 at.% Pt alloy, quenched from the solid as well as the liquid state, has been studied with the D11 neutron small-angle scattering spectrometer at ILL, Grenoble. An incident neutron wavelength of 6.7 A was used and measurements were carried out in the range of scattering vector [β=4π sin theta/lambda] from 2.8x10 -2 to 21x10 -2 A -1 . The preliminary results indicate that decomposition of this alloy at 550 0 C takes place by a spinodal mode, although deviations were observed from linear spinodal theory, even at very early times. Slower aging kinetics were observed in liquid-quenched alloy as compared with solid-quenched. Liquid quenching is more efficient in suppressing quench clustering than is solid quenching. However, liquid quenching yields an extremely fine-grained material, which thereby enhances discontinuous precipitation at grain boundaries, competing with decomposition in the bulk. A Rundman-Hilliard analysis was used for the early stages of the spinodal reaction to obtain an interdiffusion coefficient of the order of 10 -16 cm 2 s -1 at 550 0 C for the solid-quenched alloy. (Auth.)
Small-angle scattering instruments on a 1 MW long pulse spallation source
Energy Technology Data Exchange (ETDEWEB)
Olah, G.A. [Los Alamos National Lab., Chemical Science and Tehcnology Div., Biosciences and Biotechnology Group, Los aalamos, NM (United States); Hjelm, R.P. [Los Alamos National Lab., Neutron Scattering Center, Los Alamos, NM (United States); Seeger, P.A.
1995-11-01
We have designed and optimized two small-angle neutron scattering instruments for installation at a 1 MW long pulse spallation source. The first of these instruments measures a Q-domain from 0.002 to 0.44 A{sup -1}, and the second instrument from 0.00069-0.17 A{sup -1}, Design characteristics were determined and optimization was done using a Monte Carlo instrument simulation package under development at Los alamos. A performance comparison was made between these instruments with D11 at the ILL by evaluating the scattered intensity and rms resolution for the instrument response function at different Q values for various instrument configurations needed to spn a Q-range of 0.0007-0.44 A{sup -1}. We concluded that the first of these instruments outperforms D11 in both intensity and resolution over most of the Q-domain and that the second is comparable to D11. Comparisons were also made of the performance of the optimized long pulse instruments with different reflectors and with a short pulse source, from which we concluded that there is an optimal moderator-reflector combination, and that a short pulse does not substantially improve the instrument performance. (author) 7 figs., 2 tabs., 9 refs.
Small-angle scattering instruments on a 1 MW long pulse spallation source
International Nuclear Information System (INIS)
Olah, G.A.; Hjelm, R.P.; Seeger, P.A.
1995-01-01
We have designed and optimized two small-angle neutron scattering instruments for installation at a 1 MW long pulse spallation source. The first of these instruments measures a Q-domain from 0.002 to 0.44 A -1 , and the second instrument from 0.00069-0.17 A -1 , Design characteristics were determined and optimization was done using a Monte Carlo instrument simulation package under development at Los alamos. A performance comparison was made between these instruments with D11 at the ILL by evaluating the scattered intensity and rms resolution for the instrument response function at different Q values for various instrument configurations needed to spn a Q-range of 0.0007-0.44 A -1 . We concluded that the first of these instruments outperforms D11 in both intensity and resolution over most of the Q-domain and that the second is comparable to D11. Comparisons were also made of the performance of the optimized long pulse instruments with different reflectors and with a short pulse source, from which we concluded that there is an optimal moderator-reflector combination, and that a short pulse does not substantially improve the instrument performance. (author) 7 figs., 2 tabs., 9 refs
Small-angle scattering of ions or atoms by atomic hydrogen
International Nuclear Information System (INIS)
Franco, V.
1982-01-01
A theory for small-angle scattering of arbitrary medium- or high-energy atoms or ions by atomic hydrogen is described. Results are obtained in terms of the known closed-form and easily calculable Glauber-approximation scattering amplitudes for electron-hydrogen collisions and for collisions between the nucleus (treated as one charged particle) of the ion or atom and the hydrogen atom, and in terms of the transition form factor of the arbitrary ion or atom. Applications are made to the angular differential cross sections for the excitation of atomic hydrogen to its n = 2 states by singly charged ground-state helium ions having velocities of roughly between 1/2 and 1 a.u. The differential cross sections are obtained in terms of electron-hydrogen amplitudes and the known He + ground-state form factor. Comparisons are made with other calculations and with recent measurements. The results are in good agreement with the data. It is seen that the effect of the He + electron is to produce significant constructive interference at most energies
Scanning of Adsorption Hysteresis In Situ with Small Angle X-Ray Scattering.
Directory of Open Access Journals (Sweden)
Athanasios Ch Mitropoulos
Full Text Available Everett's theorem-6 of the domain theory was examined by conducting adsorption in situ with small angle x-ray scattering (SAXS supplemented by the contrast matching technique. The study focuses on the spectrum differences of a point to which the system arrives from different scanning paths. It is noted that according to this theorem at a common point the system has similar macroscopic properties. Furthermore it was examined the memory string of the system. We concluded that opposite to theorem-6: a at a common point the system can reach in a finite (not an infinite number of ways, b a correction for the thickness of the adsorbed film prior to capillary condensation is necessary, and c the scattering curves although at high-Q values coincide, at low-Q values are different indicating different microscopic states. That is, at a common point the system holds different metastable states sustained by hysteresis effects. These metastable states are the ones which highlight the way of a system back to a return point memory (RPM. Entering the hysteresis loop from different RPMs different histories are implanted to the paths toward the common point. Although in general the memory points refer to relaxation phenomena, they also constitute a characteristic feature of capillary condensation. Analogies of the no-passing rule and the adiabaticity assumption in the frame of adsorption hysteresis are discussed.
Scanning of Adsorption Hysteresis In Situ with Small Angle X-Ray Scattering
Mitropoulos, Athanasios Ch.; Favvas, Evangelos P.; Stefanopoulos, Konstantinos L.; Vansant, Etienne F.
2016-01-01
Everett’s theorem-6 of the domain theory was examined by conducting adsorption in situ with small angle x-ray scattering (SAXS) supplemented by the contrast matching technique. The study focuses on the spectrum differences of a point to which the system arrives from different scanning paths. It is noted that according to this theorem at a common point the system has similar macroscopic properties. Furthermore it was examined the memory string of the system. We concluded that opposite to theorem-6: a) at a common point the system can reach in a finite (not an infinite) number of ways, b) a correction for the thickness of the adsorbed film prior to capillary condensation is necessary, and c) the scattering curves although at high-Q values coincide, at low-Q values are different indicating different microscopic states. That is, at a common point the system holds different metastable states sustained by hysteresis effects. These metastable states are the ones which highlight the way of a system back to a return point memory (RPM). Entering the hysteresis loop from different RPMs different histories are implanted to the paths toward the common point. Although in general the memory points refer to relaxation phenomena, they also constitute a characteristic feature of capillary condensation. Analogies of the no-passing rule and the adiabaticity assumption in the frame of adsorption hysteresis are discussed. PMID:27741263
International Nuclear Information System (INIS)
Yamamoto, Katsuhiro; Sakurai, Shinichi
2006-01-01
Crystalline polymers spontaneously form hierarchical structures, which provide us a potential use as a specialty material. Recently, not only a crystalline homopolymer but also semi-crystalline block copolymers and crystalline polymer blends have been attracting interests for the study of a hierarchical structure. In order to analyze such hierarchical structures in a variety of length scales, a simultaneous measurement of small-(SAXS) and wide-angle (WAXS) X-ray scattering with differential scanning calorimetry (DSC), or with small-angle light scattering (Hv-SALS) are most suitable. In this review, we show some examples of the simultaneous measurements. With DSC, exothermic heat flow can be simultaneously measured with X-ray scattering. On the other hand, with Hv-SALS it is possible to analyze evolution of a spherulitic structure, which is the structure at the highest rank in the hierarchy. For both cases, one can realize that it is impossible to obtain good statistics for SAXS and WAXS measurements without synchrotron radiations. (author)
International Nuclear Information System (INIS)
Gereben, O; Pusztai, L; McGreevy, R L
2010-01-01
A new reverse Monte Carlo (RMC) method has been developed for creating three-dimensional structures in agreement with small angle scattering data. Extensive tests, using computer generated quasi-experimental data for aggregation processes via constrained RMC and Langevin molecular dynamics, were performed. The software is capable of fitting several consecutive time frames of scattering data, and movie-like visualization of the structure (and its evolution) either during or after the simulation is also possible.
International Nuclear Information System (INIS)
Zinke, M.
1979-01-01
Exemplified by hemoglobin, the thermodynamic equilibrium properties of the dissolved macromolecular system could be determined solely from the small angle X-ray scattering of concentrated macromolecular solutions via the intermolecular structure of the dissolved macromolecules and their intermolecular potentials. From the scattering experiment on concentrated Hb solutions the concentration dependence of the following properties of the dissolved Hb system were determined: fluctuation, isothermic compressibility, internal energy, surface tension, and osmotic pressure. (author)
Modeling the structure of RNA molecules with small-angle X-ray scattering data.
Directory of Open Access Journals (Sweden)
Michal Jan Gajda
Full Text Available We propose a novel fragment assembly method for low-resolution modeling of RNA and show how it may be used along with small-angle X-ray solution scattering (SAXS data to model low-resolution structures of particles having as many as 12 independent secondary structure elements. We assessed this model-building procedure by using both artificial data on a previously proposed benchmark and publicly available data. With the artificial data, SAXS-guided models show better similarity to native structures than ROSETTA decoys. The publicly available data showed that SAXS-guided models can be used to reinterpret RNA structures previously deposited in the Protein Data Bank. Our approach allows for fast and efficient building of de novo models of RNA using approximate secondary structures that can be readily obtained from existing bioinformatic approaches. We also offer a rigorous assessment of the resolving power of SAXS in the case of small RNA structures, along with a small multimetric benchmark of the proposed method.
Carbon Condensation during High Explosive Detonation with Time Resolved Small Angle X-ray Scattering
Hammons, Joshua; Bagge-Hansen, Michael; Nielsen, Michael; Lauderbach, Lisa; Hodgin, Ralph; Bastea, Sorin; Fried, Larry; May, Chadd; Sinclair, Nicholas; Jensen, Brian; Gustavsen, Rick; Dattelbaum, Dana; Watkins, Erik; Firestone, Millicent; Ilavsky, Jan; van Buuren, Tony; Willey, Trevor; Lawrence Livermore National Lab Collaboration; Los Alamos National Laboratory Collaboration; Washington State University/Advanced Photon Source Team
Carbon condensation during high-energy detonations occurs under extreme conditions and on very short time scales. Understanding and manipulating soot formation, particularly detonation nanodiamond, has attracted the attention of military, academic and industrial research. An in-situ characterization of these nanoscale phases, during detonation, is highly sought after and presents a formidable challenge even with today's instruments. Using the high flux available with synchrotron X-rays, pink beam small angle X-ray scattering is able to observe the carbon phases during detonation. This experimental approach, though powerful, requires careful consideration and support from other techniques, such as post-mortem TEM, EELS and USAXS. We present a comparative survey of carbon condensation from different CHNO high explosives. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344.
Search for small-angle neutron scattering in MnO at 1700K
International Nuclear Information System (INIS)
Routbort, J.L.; Epperson, J.E.; Klippert, T.E.; Goretta, K.C.
1986-01-01
A preliminary small-angle scattering (SANS) experiment has been performed on MnO single crystal at the Intense Pulsed Neutron Source. The experiment was preformed at 1700 0 K at oxygen partial pressures of 2.2 x 10 -4 , 1 x 10 2 , and 2 x 10 2 Pa, which resulted in deviations from stoichiometry of about 0.0015, 0.082, and 0.127. No statistically significant change in SANS was observed at this temperature with the pressure changes. Neither was any significant change observed in the wavelength-dependent sample transmission, also measured in-situ as a function of pressure. Therefore, either clustering of cation vacancies is negligible in MnO for these conditions, or the clusters are smaller than about 5 A. Of proposed cluster configurations, only the existence of the smallest (4:1, 6:2, or possible 8:3) appears to be consistent with these results
Magnetic phase diagram of MnSi near critical temperature studied by neutron small angle scattering
International Nuclear Information System (INIS)
Ishikawa, Yoshikazu; Arai, Masatoshi
1984-01-01
The magnetic phase diagram of MnSi near the critical temperature T sub(N)=29.5K has been studied by neutron small angle scattering at KENS. It has been found that the anomalous new phase predicted by various methods to exist around at 28 K and 2 kOe is the paramagnetic phase where the magnetic correlations exhibit the same characteristics as those found at 29.5 K and zero magnetic field. This phenomenon, together with the sharp decrease of the magnetic phase boundary at T sub(N) and the substantial increase of the satellite Q vector at this temperature, has been found not to be interpreted by the current theories. (author)
Structure of clathrin-coated vesicles from small-angle scattering experiments
DEFF Research Database (Denmark)
Pedersen, J.S.
1993-01-01
Previously published small-angle neutron and X-ray scattering data from coated vesicles, reassembled coats, and stripped vesicles have been analyzed in terms of one common model. The neutron data sets include contrast variation measurements at three different D2O solvent concentrations. The model...... used for interpreting the data has spherical symmetry and explicitly takes into account polydispersity, which is described by a Gaussian distribution. A constant thickness of the clathrin coats is assumed. The fitting of the model shows that the coated vesicles consist of a low-density outer protein....... Thus, the membrane and the high-density protein shell overlap in space, which shows that the lipid membrane contains protein. The molecular mass of the average particle is 27 x 10(6) Da. The coated vesicles consist, on average, of approximately 85% protein and 15% lipids. About 40% of the protein mass...
A new package: MySAS for small angle scattering data analysis
International Nuclear Information System (INIS)
Huang Chaoqiang; Xia Qingzhong; Yan Guanyun; Sun Guang'ai; Chen Bo
2010-01-01
In this paper, A MySAS package, which is verified on Windows XP, can easily convert two-dimensional data in small angle neutron and X-ray scattering analysis, operate individually and execute one particular operation as numerical data reduction or analysis, and graphical visualization. This MySAS package can implement the input and output routines via scanning certain properties, thus recalling completely sets of repetition input and selecting the input files. On starting from the two-dimensional files, the MySAS package can correct the anisotropic or isotropic data for physical interpretation and select the relevant pixels. Over 50 model functions are fitted by the POWELL code using χ 2 as the figure of merit function. (authors)
Energy Technology Data Exchange (ETDEWEB)
Wiedemann, Birgit; Pfleiderer, Christian; Boeni, Peter [Physik Department, Technische Universitaet Muenchen (Germany); Zhang, Shilei; Hesjedal, Thorsten [Clarendon Laboratory, Department of Physics, University of Oxford (United Kingdom); Khaydukov, Yury; Soltwedel, Olaf; Keller, Thomas [Max-Planck-Institut fuer Festkoerperforschung (Germany); Max Planck Society, Outstation at FRM-II (Germany); Muehlbauer, Sebastian [Forschungsneutronenquelle Heinz Maier Leibnitz, Technische Universitaet Muenchen (Germany); Chacon, Alfonso [Physik Department, Technische Universitaet Muenchen (Germany); Forschungsneutronenquelle Heinz Maier Leibnitz, Technische Universitaet Muenchen (Germany)
2015-07-01
The topological stability of skyrmions in bulk samples of MnSi and the observation of spin transfer torque effects at ultra-low current densities have generated great interest in skyrmions in chiral magnets as a new route towards next generation spintronics devices. Yet, the formation of skyrmions in MBE grown thin films of MnSi reported in the literature is highly controversial. We report gracing incidence small angle neutron scattering (GISANS) of the magnetic order in selected thin films of MnSi grown by state of the art MBE techniques. In combination with polarised neutron reflectometry (PNR) and magnetisation measurements of the same samples our data provide direct reciprocal space information of the incommensurate magnetic order, clarifying the nature of magnetic phase diagram.
Measuring module of spectrometer of neutron small angle scattering on the IBR pulse reactor
International Nuclear Information System (INIS)
Vagov, V.A.; Zhukov, G.P.; Kozlova, E.P.; Korobchenko, M.L.; Namsraj, Yu.; Ostanevich, Yu.M.; Savvateev, A.S.; Salamatin, I.M.; Sirotin, A.P.
1980-01-01
Equipment and software for experiments with neutron small angle scattering is described. It is intended for data acquisition, equipment control storage of collected data and their output to network of the Laboratory measuring centre. The set-up equipment includes: 9 neutron detectors with corresponding electronic apparatus, sample exchanging device, communication link, SM-3 type minicomputer of an extended configuration and some units of CAMAC electronic equipment. The software (MUR applied operatio system) is intended for the automatic performance of the given number of cycles of successive uniform runs of a given duration with the sample list at two possible filter positions. Besides, the MUR system contains test, debugging and service software. The software has been designed using the SANPO system means [ru
Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS)
Energy Technology Data Exchange (ETDEWEB)
Hura, Greg L.; Menon, Angeli L.; Hammel, Michal; Rambo, Robert P.; Poole II, Farris L.; Tsutakawa, Susan E.; Jenney Jr, Francis E.; Classen, Scott; Frankel, Kenneth A.; Hopkins, Robert C.; Yang, Sungjae; Scott, Joseph W.; Dillard, Bret D.; Adams, Michael W. W.; Tainer, John A.
2009-07-20
We present an efficient pipeline enabling high-throughput analysis of protein structure in solution with small angle X-ray scattering (SAXS). Our SAXS pipeline combines automated sample handling of microliter volumes, temperature and anaerobic control, rapid data collection and data analysis, and couples structural analysis with automated archiving. We subjected 50 representative proteins, mostly from Pyrococcus furiosus, to this pipeline and found that 30 were multimeric structures in solution. SAXS analysis allowed us to distinguish aggregated and unfolded proteins, define global structural parameters and oligomeric states for most samples, identify shapes and similar structures for 25 unknown structures, and determine envelopes for 41 proteins. We believe that high-throughput SAXS is an enabling technology that may change the way that structural genomics research is done.
A small-angle neutron scattering investigation of coke deposits on catalysts
International Nuclear Information System (INIS)
Acharya, D.R.; Hughes, R.; Allen, A.J.
1990-01-01
Small-angle neutron scattering (SANS) has been used to characterize a silica-alumina catalyst before and after coke deposition. The reaction used to deactivate the catalyst was the isomerization of xylenes. The results showed that, while most of the surface area in this type of catalyst resides in the ultrafine pores of diameters less than 1 nm occupying about 7% of the sample volume, there appears to be no coke deposition in these pores. The coke seems to coat the solid structures of 3.3-nm diameter which are of capillary shape. Such structures occupy about 6% of the sample volume. The coke was found to correspond to amonolayer of composition CH 0.3 with a density of 1660 kg/m 3
Energy Technology Data Exchange (ETDEWEB)
Mason, P.C.; Gaulin, B.D. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (CANADA); Epand, R.M. [Department of Biochemistry, McMaster University, Hamilton, Ontario, L8N 3Z5 (CANADA); Wignall, G.D.; Lin, J.S. [Center for Small-Angle Scattering Research, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
1999-03-01
High-resolution differential scanning calorimetry (DSC) and small angle neutron scattering (SANS) experiments have been conducted on large unilamellar vesicles (LUV{close_quote}s) of the phospholipid dipalmitoylphosphatidylcholine (DPPC) in excess water. The DSC results indicate a phase transition at temperatures corresponding to the gel (L{sub {beta}{sup {prime}}}) to ripple (P{sub {beta}{sup {prime}}}) phase transition seen in multilamellar vesicles of DPPC while the SANS experiments provide direct evidence for the formation of the P{sub {beta}{sup {prime}}} phase in these systems. In addition, it is shown that SANS is an effective technique for extracting structural parameters such as vesicle radius and thickness in LUV model membrane systems. {copyright} {ital 1999} {ital The American Physical Society}