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

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

Small angle X ray diffraction investigation of twinned opal_like structures

NARCIS (Netherlands)

Samusev, A.K.; Sinev, I.S.; Samusev, K.B.; Rybin, M.V.; Mistonov, A.A.; Grigoryeva, N.A.; Grigoriev, S.V.; Petukhov, A.V.; Byelov, D.; Trofimova, E.Y.; Kurdyukov, D.A.; Golubev, V.G.; Limonov, M.F.

2012-01-01

Small angle X ray diffraction from synthetic opal films has been investigated as a function of the orientation of the sample. All the observed (hkl) diffraction reflections have been interpreted. The reconstruct tion of the reciprocal lattice of the studied opal films has been carried out. The

The accurate assessment of small-angle X-ray scattering data.

Science.gov (United States)

Grant, Thomas D; Luft, Joseph R; Carter, Lester G; Matsui, Tsutomu; Weiss, Thomas M; Martel, Anne; Snell, Edward H

2015-01-01

Small-angle X-ray scattering (SAXS) has grown in popularity in recent times with the advent of bright synchrotron X-ray sources, powerful computational resources and algorithms enabling the calculation of increasingly complex models. However, the lack of standardized data-quality metrics presents difficulties for the growing user community in accurately assessing the quality of experimental SAXS data. Here, a series of metrics to quantitatively describe SAXS data in an objective manner using statistical evaluations are defined. These metrics are applied to identify the effects of radiation damage, concentration dependence and interparticle interactions on SAXS data from a set of 27 previously described targets for which high-resolution structures have been determined via X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. The studies show that these metrics are sufficient to characterize SAXS data quality on a small sample set with statistical rigor and sensitivity similar to or better than manual analysis. The development of data-quality analysis strategies such as these initial efforts is needed to enable the accurate and unbiased assessment of SAXS data quality.

Degradation of periodic multilayers as seen by small-angle x-ray scattering and x-ray diffraction

CERN Document Server

Rafaja, D; Simek, D; Zdeborova, L; Valvoda, V

2002-01-01

The capabilities of small-angle x-ray scattering (SAXS) and wide-angle x-ray diffraction (XRD) to recognize structural changes in periodic multilayers were compared on Fe/Au multilayers with different degrees of structural degradation. Experimental results have shown that both methods are equally sensitive to the multilayer degradation, i.e., to the occurrence of non-continuous interfaces, to short-circuits in the multilayer structure and to the multilayer precipitation. XRD yielded additional information on the multilayer crystallinity, whilst SAXS could better recognize fragments of a long-range periodicity (remnants of the original multilayer structure). Changes in the multilayer structure were initiated by successive annealing at 200 and 300 deg. C. Experimental data were complemented by numerical simulations performed using a combination of optical theory and the distorted wave Born approximation for SAXS or the kinematical Born approximation for XRD.

Diffraction anomalous fine structure using X-ray anomalous dispersion

International Nuclear Information System (INIS)

Soejima, Yuji; Kuwajima, Shuichiro

1998-01-01

A use of X-ray anomalous dispersion effects for structure investigation has recently been developed by using synchrotron radiation. One of the interesting method is the observation of anomalous fine structure which arise on diffraction intensity in energy region of incident X-ray at and higher than absorption edge. The phenomenon is so called Diffraction Anomalous Fine Structure (DAFS). DAFS originates in the same physical process an that of EXAFS: namely photoelectric effect at the corresponding atom and the interaction of photoelectron waves between the atom and neighboring atoms. In contrast with EXAFS, the method is available for only the crystalline materials, but shows effective advantages of the structure investigations by a use of diffraction: one is the site selectivity and the other is space selectivity. In the present study, demonstrations of a use of X-ray anomalous dispersion effect for the superstructure determination will be given for the case of PbZrO 3 , then recent trial investigations of DAFS in particular on the superlattice reflections will be introduced. In addition, we discuss about Forbidden Reflection near Edge Diffraction (FRED) which is more recently investigated as a new method of the structure analysis. (author)

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.

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 ...

Portable mini-chamber for temperature dependent studies using small angle and wide angle x-ray scattering

Science.gov (United States)

Dev, Arun Singh; Kumar, Dileep; Potdar, Satish; Pandit, Pallavi; Roth, Stephan V.; Gupta, Ajay

2018-04-01

The present work describes the design and performance of a vacuum compatible portable mini chamber for temperature dependent GISAXS and GIWAXS studies of thin films and multilayer structures. The water cooled body of the chamber allows sample annealing up to 900 K using ultra high vacuum compatible (UHV) pyrolytic boron nitride heater, thus making it possible to study the temperature dependent evolution of structure and morphology of two-dimensional nanostructured materials. Due to its light weight and small size, the chamber is portable and can be accommodated at synchrotron facilities worldwide. A systematic illustration of the versatility of the chamber has been demonstrated at beamline P03, PETRA-III, DESY, Hamburg, Germany. Temperature dependent grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) measurements were performed on oblique angle deposited Co/Ag multilayer structure, which jointly revealed that the surface diffusion in Co columns in Co/Ag multilayer enhances by increasing temperature from RT to ˜573 K. This results in a morphology change from columnar tilted structure to densely packed morphological isotropic multilayer.

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.

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

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.

Difference structures from time-resolved small-angle and wide-angle x-ray scattering

Science.gov (United States)

Nepal, Prakash; Saldin, D. K.

2018-05-01

Time-resolved small-angle x-ray scattering/wide-angle x-ray scattering (SAXS/WAXS) is capable of recovering difference structures directly from difference SAXS/WAXS curves. It does so by means of the theory described here because the structural changes in pump-probe detection in a typical time-resolved experiment are generally small enough to be confined to a single residue or group in close proximity which is identified by a method akin to the difference Fourier method of time-resolved crystallography. If it is assumed, as is usual with time-resolved structures, that the moved atoms lie within the residue, the 100-fold reduction in the search space (assuming a typical protein has about 100 residues) allows the exaction of the structure by a simulated annealing algorithm with a huge reduction in computing time and leads to a greater resolution by varying the positions of atoms only within that residue. This reduction in the number of potential moved atoms allows us to identify the actual motions of the individual atoms. In the case of a crystal, time-resolved calculations are normally performed using the difference Fourier method, which is, of course, not directly applicable to SAXS/WAXS. The method developed in this paper may be thought of as a substitute for that method which allows SAXS/WAXS (and hence disordered molecules) to also be used for time-resolved structural work.

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)

Investigation of polydisperse, disordered, and fractal systems by small-angle x-ray and neutron scattering

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

Anomalous x-ray scattering

International Nuclear Information System (INIS)

Wendin, G.

1979-01-01

The availability of tunable synchrotron radiation has made it possible systematically to perform x-ray diffraction studies in regions of anomalous scattering near absorption edges, e.g. in order to derive phase information for crystal structure determination. An overview is given of recent experimental and theoretical work and discuss the properties of the anomalous atomic scattering factor, with emphasis on threshold resonances and damping effects. The results are applied to a discussion of the very strong anomalous dispersion recently observed near the L 3 edge in a cesium complex. Also given is an overview of elements and levels where similar behavior can be expected. Finally, the influence of solid state and chemical effects on the absorption edge structure is discussed. 64 references

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

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)

Structure investigation of metal ions clustering in dehydrated gel using x-ray anomalous dispersion effect

CERN Document Server

Soejima, Y; Sugiyama, M; Annaka, M; Nakamura, A; Hiramatsu, N; Hara, K

2003-01-01

The structure of copper ion clusters in dehydrated N-isopropylacrylamide/sodium acrylate (NIPA/SA) gel has been studied by means of small angle X-ray scattering (SAXS) method. In order to distinguish the intensity scattered by Cu ions, the X-ray anomalous dispersion effect around the Cu K absorption edge has been coupled with SAXS. It is found that the dispersion effect dependent on the incident X-ray energy is remarkable only at the momentum transfer q = 0.031 A sup - sup 1 , where a SAXS peak is observed. The results indicate that copper ions form clusters in the dehydrated gel, and that the mean size of clusters is the same as that of SA clusters produced by microphase separation. It is therefore naturally presumed that copper ions are adsorbed into the SA molecules. On the basis of the presumption, a mechanism is proposed for microphase-separation and clustering of Cu ions.

Processing two-dimensional X-ray diffraction and small-angle scattering data in DAWN 2.

Science.gov (United States)

Filik, J; Ashton, A W; Chang, P C Y; Chater, P A; Day, S J; Drakopoulos, M; Gerring, M W; Hart, M L; Magdysyuk, O V; Michalik, S; Smith, A; Tang, C C; Terrill, N J; Wharmby, M T; Wilhelm, H

2017-06-01

A software package for the calibration and processing of powder X-ray diffraction and small-angle X-ray scattering data is presented. It provides a multitude of data processing and visualization tools as well as a command-line scripting interface for on-the-fly processing and the incorporation of complex data treatment tasks. Customizable processing chains permit the execution of many data processing steps to convert a single image or a batch of raw two-dimensional data into meaningful data and one-dimensional diffractograms. The processed data files contain the full data provenance of each process applied to the data. The calibration routines can run automatically even for high energies and also for large detector tilt angles. Some of the functionalities are highlighted by specific use cases.

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...

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

Comparison of X-ray and neutron small-angle scattering from an Al-Zn alloy

International Nuclear Information System (INIS)

Gerold, V.; Epperson, J.E.; Gerstenberg, K.W.

1978-01-01

The normalized integrated small-angle scattered intensity for Al-Zn alloys should be independent of whether the measurements are made with X-rays or neutrons. In order to check this, and thus the correction and standardization processes, the small-angle scattering from an Al-5.05 at.% Zn alloy containing GP zones was measured with these two types of radiation. The data were corrected and converted to absolute units with reference to the commonly accepted secondary standards: vanadium for the neutron data and polyethylene (Lupolen) for the X-ray data. The results are shown to differ by, at best, 6% if reasonable values for the change in atomic volume with alloy composition are taken into account. These findings are compared with those available from the literature, and the consistency is found to be somewhat lacking. Additional careful work is clearly needed to determine if the difficulty is traceable to the data correction or to the conversion to absolute units. (Auth.)

Small-angle x-ray scattering in amorphous silicon: A computational study

Science.gov (United States)

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.

Small-angle and wide-angle X-ray scattering study on the bilayer structure of synthetic and bovine heart cardiolipins

International Nuclear Information System (INIS)

Takahashi, Hiroshi; Hayakawa, Tomohiro; Ito, Kazuki; Takata, Masaki; Kobayashi, Toshihide

2010-01-01

Cardiolipin (CL) is a membrane phospholipid containing four fatty acid chains. CL plays an important role in energy transformation in mitochondria. The disorder of CL biosynthesis is involved in a genetic disease, Barth syndrome. Alteration of fatty acid composition of CLs has been found in Barth syndrome patients, i.e., the decrease of unsaturated fatty acid chains. In this study, we investigated how the degree of saturation alters the structure of CL bilayers by using X-ray scattering. Bovine heart CL and two synthetic CLs were compared. Fatty acid compositions of these three CLs have different saturation. Small-angle X-ray scattering data showed that the decrease of the number of double bonds in the unsaturated fatty acid chains causes to thicken the CL bilayers. In addition, wide-angle X-ray scattering data suggested that the decrease reduces the degree of disorder of the hydrophobic region in a liquid crystalline phase. These results may be related to the dysfunction of mitochondria in Barth syndrome.

Small-angle and wide-angle X-ray scattering study on the bilayer structure of synthetic and bovine heart cardiolipins

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Hiroshi [Biophysics Laboratory, Department of Chemistry and Chemical Biology, Gunma University, Maebashi, Gunma, 371-8510 (Japan); Hayakawa, Tomohiro [Life Science Laboratory, Advanced Materials Laboratories, Sony Corporation, Yushima, Bunkyo-ku, Tokyo, 113-8510 (Japan); Ito, Kazuki; Takata, Masaki [Structural Materials Science Laboratory, RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan); Kobayashi, Toshihide, E-mail: htakahas@chem-bio.gunma-u.ac.j [Lipid Biology Laboratory, RIKEN, Wako, Saitama 351-0198 (Japan)

2010-10-01

Cardiolipin (CL) is a membrane phospholipid containing four fatty acid chains. CL plays an important role in energy transformation in mitochondria. The disorder of CL biosynthesis is involved in a genetic disease, Barth syndrome. Alteration of fatty acid composition of CLs has been found in Barth syndrome patients, i.e., the decrease of unsaturated fatty acid chains. In this study, we investigated how the degree of saturation alters the structure of CL bilayers by using X-ray scattering. Bovine heart CL and two synthetic CLs were compared. Fatty acid compositions of these three CLs have different saturation. Small-angle X-ray scattering data showed that the decrease of the number of double bonds in the unsaturated fatty acid chains causes to thicken the CL bilayers. In addition, wide-angle X-ray scattering data suggested that the decrease reduces the degree of disorder of the hydrophobic region in a liquid crystalline phase. These results may be related to the dysfunction of mitochondria in Barth syndrome.

Anomalous x-ray radiation of beam plasma

International Nuclear Information System (INIS)

Dimitrov, S.K.; Zavyalov, M.A.; Mikhin, S.G.; Tarasenkov, V.A.; Telkovskij, V.G.; Khrabrov, V.A.

1985-01-01

The properties of non-equilibrium stationary plasma under the conditions of the planned plasma-chemical reactors based on beam-plasma discharge were investigated. The x-ray spectrum of the beam-plasma was measured and anomalous spectral properties were analyzed. Starting with some critical pressure the anomalous radiation was added to the classical bremsstrahlung spectrum. The occurrence of anomalous radiation can be used to diagnose the condition of beam transportation in such systems. (D.Gy.)

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.

Preliminary small-angle X-ray scattering and X-ray diffraction studies of the BTB domain of lola protein from Drosophila melanogaster

Science.gov (United States)

Boyko, K. M.; Nikolaeva, A. Yu.; Kachalova, G. S.; Bonchuk, A. N.; Dorovatovskii, P. V.; Popov, V. O.

2017-11-01

The Drosophila genome has several dozens of transcription factors (TTK group) containing BTB domains assembled into octamers. The LOLA protein belongs to this family. The purification, crystallization, and preliminary X-ray diffraction and small-angle X-ray scattering (SAXS) studies of the BTB domain of this protein are reported. The crystallization conditions were found by the vapor-diffusion technique. A very low diffraction resolution (8.7 Å resolution) of the crystals was insufficient for the determination of the threedimensional structure of the BTB domain. The SAXS study demonstrated that the BTB domain of the LOLA protein exists as an octamer in solution.

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)

A high resolution, high counting rate bidimensional, MWPC imaging detector for small angle X-ray diffraction studies

International Nuclear Information System (INIS)

Bateman, J.E.; Connolly, J.F.; Sawyer, E.C.; Stephenson, R.

1981-07-01

The performance is reported of a 200 mm x 200 mm X-ray imaging MWPC aimed at applications in small angle X-ray diffraction and scattering. With quantum energies of approximately 8 keV high spatial resolution (+- 0.5 mm x +- 0.14 mm) with a capability for data taking at >approximately 350 kHz is reported. The detection efficiency is approximately 75% and the detector operates as a sealed unit with a long lifetime. (author)

Interpretation and Utility of the Moments of Small-Angle X-Ray Scattering Distributions.

Science.gov (United States)

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.

Discovery of Hard Nonthermal Pulsed X-Ray Emission from the Anomalous X-Ray Pulsar 1E 1841-045

NARCIS (Netherlands)

Kuiper, L.; Hermsen, W.; Méndez, R.M.

2004-01-01

We report the discovery of nonthermal pulsed X-ray/soft gamma-ray emission up to ~150 keV from the anomalous 11.8 s X-ray pulsar AXP 1E 1841-045 located near the center of supernova remnant Kes 73 using Rossi X-Ray Timing Explorer (RXTE) Proportional Counter Array and High Energy X-Ray Timing

The modular small-angle X-ray scattering data correction sequence.

Science.gov (United States)

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.

Structural dissection of human metapneumovirus phosphoprotein using small angle x-ray scattering.

Science.gov (United States)

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.

Using angular dispersion and anomalous transmission to shape ultramonochromatic x rays

Energy Technology Data Exchange (ETDEWEB)

Shvyd' ko, Yuri; Stoupin, Stanislav; Shu, Deming; Khachatryan, Ruben [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2011-11-15

Optical spectrometers, instruments that work with highly monochromatic light, are commonly rated by the spectral bandwidth, which defines the ability to resolve closely spaced spectral components. Another equally important feature is the spectral contrast, the ability to detect faint objects among these components. Here we demonstrate that a combined effect of angular dispersion (AD) and anomalous transmission (AT) of x rays in Bragg reflection from asymmetrically cut crystals can shape spectral distributions of x rays to profiles with high contrast and small bandwidths. The AD and AT x-ray optics is implemented as a five-reflection, three-crystal arrangement featuring a combination of the above-mentioned attributes so desirable for x-ray monochromators and analyzers: a spectral contrast of {approx_equal} 500, a bandwidth of {approx_equal} 0.46 meV, and a remarkably large angular acceptance of {approx_equal} 107 {mu}rad with 9.1 keV x rays. The new optics can become a foundation for the next-generation inelastic x-ray scattering spectrometers for studies of atomic dynamics.

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)

Application of ultra-small-angle X-ray scattering / X-ray photon correlation spectroscopy to relate equilibrium or non-equilibrium dynamics to microstructure

Science.gov (United States)

Allen, Andrew; Zhang, Fan; Levine, Lyle; Ilavsky, Jan

2013-03-01

Ultra-small-angle X-ray scattering (USAXS) can probe microstructures over the nanometer-to-micrometer scale range. Through use of a small instrument entrance slit, X-ray photon correlation spectroscopy (XPCS) exploits the partial coherence of an X-ray synchrotron undulator beam to provide unprecedented sensitivity to the dynamics of microstructural change. In USAXS/XPCS studies, the dynamics of local structures in a scale range of 100 nm to 1000 nm can be related to an overall hierarchical microstructure extending from 1 nm to more than 1000 nm. Using a point-detection scintillator mode, the equilibrium dynamics at ambient temperature of small particles (which move more slowly than nanoparticles) in aqueous suspension have been quantified directly for the first time. Using a USAXS-XPCS scanning mode for non-equilibrium dynamics incipient processes within dental composites have been elucidated, prior to effects becoming detectable using any other technique. Use of the Advanced Photon Source, an Office of Science User Facility operated for the United States Department of Energy (U.S. DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.

Small-angle scattering of polychromatic X-rays: effects of bandwidth, spectral shape and high harmonics

Energy Technology Data Exchange (ETDEWEB)

Chen, Sen; Luo, Sheng-Nian

2018-02-16

Polychromatic X-ray sources can be useful for photon-starved small-angle X-ray scattering given their high spectral fluxes. Their bandwidths, however, are 10–100 times larger than those using monochromators. To explore the feasibility, ideal scattering curves of homogeneous spherical particles for polychromatic X-rays are calculated and analyzed using the Guinier approach, maximum entropy and regularization methods. Monodisperse and polydisperse systems are explored. The influence of bandwidth and asymmetric spectra shape are exploredviaGaussian and half-Gaussian spectra. Synchrotron undulator spectra represented by two undulator sources of the Advanced Photon Source are examined as an example, as regards the influence of asymmetric harmonic shape, fundamental harmonic bandwidth and high harmonics. The effects of bandwidth, spectral shape and high harmonics on particle size determination are evaluated quantitatively.

Beyond simple small-angle X-ray scattering: developments in online complementary techniques and sample environments.

Science.gov (United States)

Bras, Wim; Koizumi, Satoshi; Terrill, Nicholas J

2014-11-01

Small- and wide-angle X-ray scattering (SAXS, WAXS) are standard tools in materials research. The simultaneous measurement of SAXS and WAXS data in time-resolved studies has gained popularity due to the complementary information obtained. Furthermore, the combination of these data with non X-ray based techniques, via either simultaneous or independent measurements, has advanced understanding of the driving forces that lead to the structures and morphologies of materials, which in turn give rise to their properties. The simultaneous measurement of different data regimes and types, using either X-rays or neutrons, and the desire to control parameters that initiate and control structural changes have led to greater demands on sample environments. Examples of developments in technique combinations and sample environment design are discussed, together with a brief speculation about promising future developments.

Small-angle scattering of polychromatic X-rays: effects of bandwidth, spectral shape and high harmonics.

Science.gov (United States)

Chen, Sen; Luo, Sheng Nian

2018-03-01

Polychromatic X-ray sources can be useful for photon-starved small-angle X-ray scattering given their high spectral fluxes. Their bandwidths, however, are 10-100 times larger than those using monochromators. To explore the feasibility, ideal scattering curves of homogeneous spherical particles for polychromatic X-rays are calculated and analyzed using the Guinier approach, maximum entropy and regularization methods. Monodisperse and polydisperse systems are explored. The influence of bandwidth and asymmetric spectra shape are explored via Gaussian and half-Gaussian spectra. Synchrotron undulator spectra represented by two undulator sources of the Advanced Photon Source are examined as an example, as regards the influence of asymmetric harmonic shape, fundamental harmonic bandwidth and high harmonics. The effects of bandwidth, spectral shape and high harmonics on particle size determination are evaluated quantitatively.

Studying nanostructure gradients in injection-molded polypropylene/montmorillonite composites by microbeam small-angle x-ray scattering

DEFF Research Database (Denmark)

Stribeck, Norbert; Schneider, Konrad; Zeinolebadi, Ahmad

2014-01-01

The core–shell structure in oriented cylindrical rods of polypropylene (PP) and nanoclay composites (NCs) from PP and montmorillonite (MMT) is studied by microbeam small-angle x-ray scattering (SAXS). The structure of neat PP is almost homogeneous across the rod showing regular semicrystalline......-shaped phyllosilicate filler particles....

Automated microfluidic sample-preparation platform for high-throughput structural investigation of proteins by small-angle X-ray scattering

DEFF Research Database (Denmark)

Lafleur, Josiane P.; Snakenborg, Detlef; Nielsen, Søren Skou

2011-01-01

A new microfluidic sample-preparation system is presented for the structural investigation of proteins using small-angle X-ray scattering (SAXS) at synchrotrons. The system includes hardware and software features for precise fluidic control, sample mixing by diffusion, automated X-ray exposure...... control, UV absorbance measurements and automated data analysis. As little as 15 l of sample is required to perform a complete analysis cycle, including sample mixing, SAXS measurement, continuous UV absorbance measurements, and cleaning of the channels and X-ray cell with buffer. The complete analysis...

Neutron and synchrotorn x-ray small angle scattering instruments for applications in biology at the Brookhaven National Laboratory

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

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.

Beyond simple small-angle X-ray scattering: developments in online complementary techniques and sample environments

Directory of Open Access Journals (Sweden)

Wim Bras

2014-11-01

Full Text Available Small- and wide-angle X-ray scattering (SAXS, WAXS are standard tools in materials research. The simultaneous measurement of SAXS and WAXS data in time-resolved studies has gained popularity due to the complementary information obtained. Furthermore, the combination of these data with non X-ray based techniques, via either simultaneous or independent measurements, has advanced understanding of the driving forces that lead to the structures and morphologies of materials, which in turn give rise to their properties. The simultaneous measurement of different data regimes and types, using either X-rays or neutrons, and the desire to control parameters that initiate and control structural changes have led to greater demands on sample environments. Examples of developments in technique combinations and sample environment design are discussed, together with a brief speculation about promising future developments.

Structure factor of dimyristoylphosphatidylcholine unilamellar vesicles: small-angle x-ray scattering study

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)

Structure Factor of Dimyristoylphosphatidylcholine Unilamellar Vesicles Small-Angle X-Ray Scattering Study

CERN Document Server

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).

Anomalous scattering, transport, and spatial distribution of X-ray fluorescence at the exit of polycapillary structures

Energy Technology Data Exchange (ETDEWEB)

Mazuritskiy, M. I., E-mail: mazurmik@gmail.com; Lerer, A. M.; Makhno, P. V. [Southern Federal University (Russian Federation)

2016-12-15

The angular distribution of the X-ray intensity at the exit of microchannel plates at grazing incidence of monochromatic radiation on the walls of microcapillaries has been investigated. The angles and energies of the primary radiation quanta at which the synchrotron beam excites X-ray fluorescence propagating inside polycapillary structures have been determined. The angular dependences of the intensity distribution of X-rays transmitted through the microcapillaries have been studied theoretically and experimentally for energies corresponding to the region of anomalous dispersion near the L{sub 2,3} absorption edges of silicon. The propagation of waves in hollow polycapillary waveguides, the excitation of X-ray fluorescence, and the X-ray diffraction at the exit of microchannel plates have been modeled mathematically. The mathematical model takes into account the presence of a transition layer on the microchannel surface.

Small-angle X-ray scattering studies of metastable intermediates of beta-lactoglobulin isolated after heat-induced aggregation

DEFF Research Database (Denmark)

Carrotta, R.; Arleth, L.; Pedersen, J.S.

2003-01-01

Small-angle x-ray scattering was used for studying intermediate species, isolated after heat-induced aggregation of the A variant of bovine P-lactoglobulin. The intermediates were separated in two fractions, the heated metastable dimer and heated metastable oligomers larger than the dimer. The pa...

Small-angle X-ray scattering at high brilliance european synchrotrons for biotechnology and nano-technology

International Nuclear Information System (INIS)

Svergun, D.; Malfois, M.; Svergun, D.; Douka, M.; Riekel, Ch.; Perez, J.; Roessle, M.; Amenitsch, H.; Gunter Grossman, J.; Vestergaard, B.; Receveur-Brechot, V.; Roth, St.V.; Ferrari, E.

2007-01-01

Different issues such as micro-fluidic devices for SAXS (small-angle X-ray diffraction), the use of electro-spray and ion trapping for SAXS in the gas phase, the study of flexible and disordered proteins through SAXS, the time-resolved SAXS studies in solution, or the study of nano-structured soft materials, were addressed in this workshop. This document gathers the transparencies of the presentations

Small-angle X-ray scattering at high brilliance european synchrotrons for biotechnology and nano-technology

Energy Technology Data Exchange (ETDEWEB)

Svergun, D.; Malfois, M. [EMBL c/o DESY, Hamburg (Germany); Svergun, D. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation); Douka, M. [Commission Europeenne, DG III, Bruxelles (Belgium); Riekel, Ch. [European Synchrotron Radiation Facility (ESRF), 38 - Grenoble (France); Perez, J. [Soleil, 91 - Saclay (France); Roessle, M. [European Molecular Biology Laboratory (EMBL), 38 - Grenoble (France); Amenitsch, H. [IBN/Elettra (Germany); Gunter Grossman, J. [Daresbury Synchrotron Radiation Source (SRS) (United Kingdom); Vestergaard, B. [University of Pharmaceutical Sciences, Copenhagen (Denmark); Receveur-Brechot, V. [Centre National de la Recherche Scientifique (CNRS/AFMB), 13 - Marseille (France); Roth, St.V. [Deutsches Elektronen Synchrotron (HASYLAB), Hamburg (Germany); Ferrari, E. [National Institute for the Physics of Matter (CNR-INFM), Trieste (Italy)

2007-07-01

Different issues such as micro-fluidic devices for SAXS (small-angle X-ray diffraction), the use of electro-spray and ion trapping for SAXS in the gas phase, the study of flexible and disordered proteins through SAXS, the time-resolved SAXS studies in solution, or the study of nano-structured soft materials, were addressed in this workshop. This document gathers the transparencies of the presentations.

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

GALAXI: Gallium anode low-angle x-ray instrument

Directory of Open Access Journals (Sweden)

Emmanuel Kentzinger

2016-03-01

Full Text Available The high brilliance laboratory small angle X-ray scattering instrument GALAXI, which is operated by JCNS, Forschungszentrum Jülich, permits the investigation of chemical correlations in bulk materials or of structures deposited on a surface at nanometre and mesoscopic length scales. The instrument is capable to perform GISAXS experiments in reflection at grazing incidence as well as SAXS experiments in transmission geometry. The X-ray flux on sample is comparable or higher than the one obtained at a comparable beamline at a second generation synchrotron radiation source.

Mineral crystal alignment in mineralized fracture callus determined by 3D small-angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Liu Yifei; Manjubala, Inderchand; Fratzl, Peter [Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam (Germany); Roschger, Paul [4th Medical Department, Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1140 Vienna (Austria); Schell, Hanna; Duda, Georg N, E-mail: fratzl@mpikg.mpg.d [Julius Wolff Institut and Center for Musculoskeletal Surgery, Charite- University Medicine Berlin, Augustenburger Platz 1, 13353 Berlin (Germany)

2010-10-01

Callus tissue formed during bone fracture healing is a mixture of different tissue types as revealed by histological analysis. But the structural characteristics of mineral crystals within the healing callus are not well known. Since two-dimensional (2D) scanning small-angle X-ray scattering (sSAXS) patterns showed that the size and orientation of callus crystals vary both spatially and temporally [1] and 2D electron microscopic analysis implies an anisotropic property of the callus morphology, the mineral crystals within the callus are also expected to vary in size and orientation in 3D. Three-dimensional small-angle X-ray scattering (3D SAXS), which combines 2D SAXS patterns collected at different angles of sample tilting, has been previously applied to investigate bone minerals in horse radius [2] and oim/oim mouse femur/tibia [3]. We implement a similar 3D SAXS method but with a different way of data analysis to gather information on the mineral alignment in fracture callus. With the proposed accurate yet fast assessment of 3D SAXS information, it was shown that the plate shaped mineral particles in the healing callus were aligned in groups with their predominant orientations occurring as a fiber texture.

Mineral crystal alignment in mineralized fracture callus determined by 3D small-angle X-ray scattering

International Nuclear Information System (INIS)

Liu Yifei; Manjubala, Inderchand; Fratzl, Peter; Roschger, Paul; Schell, Hanna; Duda, Georg N

2010-01-01

Callus tissue formed during bone fracture healing is a mixture of different tissue types as revealed by histological analysis. But the structural characteristics of mineral crystals within the healing callus are not well known. Since two-dimensional (2D) scanning small-angle X-ray scattering (sSAXS) patterns showed that the size and orientation of callus crystals vary both spatially and temporally [1] and 2D electron microscopic analysis implies an anisotropic property of the callus morphology, the mineral crystals within the callus are also expected to vary in size and orientation in 3D. Three-dimensional small-angle X-ray scattering (3D SAXS), which combines 2D SAXS patterns collected at different angles of sample tilting, has been previously applied to investigate bone minerals in horse radius [2] and oim/oim mouse femur/tibia [3]. We implement a similar 3D SAXS method but with a different way of data analysis to gather information on the mineral alignment in fracture callus. With the proposed accurate yet fast assessment of 3D SAXS information, it was shown that the plate shaped mineral particles in the healing callus were aligned in groups with their predominant orientations occurring as a fiber texture.

Insights into the interactions among Surfactin, betaines, and PAM: surface tension, small-angle neutron scattering, and small-angle X-ray scattering study.

Science.gov (United States)

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.

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)

Rapid small-angle X-ray diffraction of a tonically contracting molluscan smooth muscle recorded with imaging plates

International Nuclear Information System (INIS)

Tajima, Y.; Okada, K.; Yoshida, O.; Seto, T.; Amemiya, Y.

1989-01-01

Small-angle X-ray diffraction patterns from the anterior byssus retractor muscles of Mytilus edulis contracting tonically in response to stimulation with acetylcholine were recorded in a 30 s exposure with synchrotron radiation and a high-sensitivity X-ray area detector called an imaging plate. The 190 A layer line from the thin filaments increased in intensity with increase in tonic tension up to 6x10 4 kg m -2 . Above this value, the layer-line intensity remained almost constant and comparable to that for a contracting skeletal muscle, indicating that the same structural changes of the thin filaments occur in both muscles. (orig.)

Studies of protein structure in solution and protein folding using synchrotron small-angle x-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Chen, Lingling [Stanford Univ., CA (United States)

1996-04-01

Synchrotron small angle x-ray scattering (SAXS) has been applied to the structural study of several biological systems, including the nitrogenase complex, the heat shock cognate protein (hsc70), and lysozyme folding. The structural information revealed from the SAXS experiments is complementary to information obtained by other physical and biochemical methods, and adds to our knowledge and understanding of these systems.

Compact structure of ribosomal protein S4 in solution as revealed by small-angle X-ray scattering

International Nuclear Information System (INIS)

Serdyuk, I.N.; Sarkisyan, M.A.; Gogia, Z.V.

1981-01-01

The authors report the results of a small-angle X-ray scattering study of ribosomal protein preparations obtained by neutron scattering method. The theoretical resolution of the diffractometer (Kratky camera, the entrance slit 80 μm, the receiving slit 190 μm, the sample-detector distance 20.4 cm) was the same as the resolution of X-ray diffractometers, on which high rsub(g) values for ribosomal proteins were obtained. They used protein S4 adjusted to 20 mg/ml without any essential loss of solubility. The scattering indicatrix obtained in a wide range of angles has demonstrated that the X-ray rsub(g) obtained here coincides with the earlier obtained neutron rsub(g) and the outer part of the scattering curve is similar to that of slightly elongated compact bodies. They conclude that all discrepancies between their data on the study of ribosomal protein structure in solution and other data are not connected with the characteristics of the instruments used but only with the quality of the protein preparations. (Auth.)

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.)

Carbon Condensation during High Explosive Detonation with Time Resolved Small Angle X-ray Scattering

Science.gov (United States)

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.

Grazing incidence small angle X-ray scattering study of silver nanoparticles in ion-exchanged glasses

Energy Technology Data Exchange (ETDEWEB)

Cheng, Weidong, E-mail: 57399942@qq.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wu, Zhaojun [Department of Practice Teaching and Equipment Management, Qiqihar University, Qiqihar 161006 (China); Gu, Xiaohua [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Xing, Xueqing; Mo, Guang [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Wu, Zhonghua, E-mail: wuzh@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2015-05-15

The size and distribution of silver nanoparticles in ion-exchanged silicate glass induced by thermal treatments in air at different temperatures were investigated by means of grazing incidence small angle X-ray scattering technique, X-ray diffraction and optical absorption spectra. Silver–sodium ion exchange of soda-lime silicate glasses was done at 350 °C for 240 min, then the samples were treated by thermal annealing in air at different temperatures 400, 500 and 550 °C, respectively, for 1 h. After the annealing treatment above 400 °C for 1 h, smaller Ag nanoparticles occurred, together with bigger ones. Both dissolution of smaller Ag nanoparticles and diffusion of larger ones are discussed in these stages of annealing in this contribution.

Purification, crystallization, small-angle X-ray scattering and preliminary X-ray diffraction analysis of the SH2 domain of the Csk-homologous kinase

International Nuclear Information System (INIS)

Gunn, Natalie J.; Gorman, Michael A.; Dobson, Renwick C. J.; Parker, Michael W.; Mulhern, Terrence D.

2011-01-01

The Src-homology 2 (SH2) domain of Csk-family protein tyrosine kinases acts as a conformational switch to regulate their catalytic activity, which in turn promotes the inhibition of their proto-oncogenic targets, the Src-family kinases. Here, the expression, purification, small-angle X-ray scattering and preliminary diffraction analysis of the SH2 domain of the Csk-homologous kinase is reported. The C-terminal Src kinase (Csk) and Csk-homologous kinase (CHK) are endogenous inhibitors of the proto-oncogenic Src family of protein tyrosine kinases (SFKs). Phosphotyrosyl peptide binding to their Src-homology 2 (SH2) domains activates Csk and CHK, enhancing their ability to suppress SFK signalling; however, the detailed mechanistic basis of this activation event is unclear. The CHK SH2 was expressed in Escherichia coli and the purified protein was characterized as monomeric by synchrotron small-angle X-ray scattering in-line with size-exclusion chromatography. The CHK SH2 crystallized in 0.2 M sodium bromide, 0.1 M bis-Tris propane pH 6.5 and 20% polyethylene glycol 3350 and the best crystals diffracted to ∼1.6 Å resolution. The crystals belonged to space group P2, with unit-cell parameters a = 25.8, b = 34.6, c = 63.2 Å, β = 99.4°

Microstructural characterization of dental zinc phosphate cements using combined small angle neutron scattering and microfocus X-ray computed tomography

Czech Academy of Sciences Publication Activity Database

Viani, Alberto; Sotiriadis, Konstantinos; Kumpová, Ivana; Mancini, L.; Appavou, M.-S.

2017-01-01

Roč. 33, č. 4 (2017), s. 402-417 ISSN 0109-5641 R&D Projects: GA MŠk(CZ) LO1219 Keywords : zinc phosphate cements * small angle neutron scattering * X-ray micro-computed tomography * X-ray powder diffraction * zinc oxide * acid-base cements Subject RIV: JJ - Other Materials OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics Impact factor: 4.070, year: 2016 https://www.sciencedirect.com/science/article/pii/S0109564116305127

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)

Automated acquisition and analysis of small angle X-ray scattering data

International Nuclear Information System (INIS)

Franke, Daniel; Kikhney, Alexey G.; Svergun, Dmitri I.

2012-01-01

Small Angle X-ray Scattering (SAXS) is a powerful tool in the study of biological macromolecules providing information about the shape, conformation, assembly and folding states in solution. Recent advances in robotic fluid handling make it possible to perform automated high throughput experiments including fast screening of solution conditions, measurement of structural responses to ligand binding, changes in temperature or chemical modifications. Here, an approach to full automation of SAXS data acquisition and data analysis is presented, which advances automated experiments to the level of a routine tool suitable for large scale structural studies. The approach links automated sample loading, primary data reduction and further processing, facilitating queuing of multiple samples for subsequent measurement and analysis and providing means of remote experiment control. The system was implemented and comprehensively tested in user operation at the BioSAXS beamlines X33 and P12 of EMBL at the DORIS and PETRA storage rings of DESY, Hamburg, respectively, but is also easily applicable to other SAXS stations due to its modular design.

On the Casimir scaling violation in the cusp anomalous dimension at small angle

Science.gov (United States)

Grozin, Andrey; Henn, Johannes; Stahlhofen, Maximilian

2017-10-01

We compute the four-loop n f contribution proportional to the quartic Casimir of the QCD cusp anomalous dimension as an expansion for small cusp angle ϕ. This piece is gauge invariant, violates Casimir scaling, and first appears at four loops. It requires the evaluation of genuine non-planar four-loop Feynman integrals. We present results up to O({φ}^4) . One motivation for our calculation is to probe a recent conjecture on the all-order structure of the cusp anomalous dimension. As a byproduct we obtain the four-loop HQET wave function anomalous dimension for this color structure.

Alzheimer's disease imaging biomarkers using small-angle x-ray scattering

Science.gov (United States)

Choi, Mina; Alam, Nadia; Dahal, Eshan; Ghammraoui, Bahaa; Badano, Aldo

2016-03-01

There is a need for novel imaging techniques for the earlier detection of Alzheimer's disease (AD). Two hallmarks of AD are amyloid beta (Aβ) plaques and tau tangles that are formed in the brain. Well-characterized x-ray cross sections of Aβ and tau proteins in a variety of structural states could potentially be used as AD biomarkers for small-angle x-ray scattering (SAXS) imaging without the need for injectable probes or contrast agents. First, however, the protein structures must be controlled and measured to determine accurate biomarkers for SAXS imaging. Here we report SAXS measurements of Aβ42 and tau352 in a 50% dimethyl sulfoxide (DMSO) solution in which these proteins are believed to remain monomeric because of the stabilizing interaction of DMSO solution. Our SAXS analysis showed the aggregation of both proteins. In particular, we found that the aggregation of Aβ42 slowly progresses with time in comparison to tau352 that aggregates at a faster rate and reaches a steady-state. Furthermore, the measured signals were compared to the theoretical SAXS profiles of Aβ42 monomer, Aβ42 fibril, and tau352 that were computed from their respective protein data bank structures. We have begun the work to systematically control the structural states of these proteins in vitro using various solvent conditions. Our future work is to utilize the distinct SAXS profiles of various structural states of Aβ and tau to build a library of signals of interest for SAXS imaging in brain tissue.

A customizable software for fast reduction and analysis of large X-ray scattering data sets: applications of the new DPDAK package to small-angle X-ray scattering and grazing-incidence small-angle X-ray scattering.

Science.gov (United States)

Benecke, Gunthard; Wagermaier, Wolfgang; Li, Chenghao; Schwartzkopf, Matthias; Flucke, Gero; Hoerth, Rebecca; Zizak, Ivo; Burghammer, Manfred; Metwalli, Ezzeldin; Müller-Buschbaum, Peter; Trebbin, Martin; Förster, Stephan; Paris, Oskar; Roth, Stephan V; Fratzl, Peter

2014-10-01

X-ray scattering experiments at synchrotron sources are characterized by large and constantly increasing amounts of data. The great number of files generated during a synchrotron experiment is often a limiting factor in the analysis of the data, since appropriate software is rarely available to perform fast and tailored data processing. Furthermore, it is often necessary to perform online data reduction and analysis during the experiment in order to interactively optimize experimental design. This article presents an open-source software package developed to process large amounts of data from synchrotron scattering experiments. These data reduction processes involve calibration and correction of raw data, one- or two-dimensional integration, as well as fitting and further analysis of the data, including the extraction of certain parameters. The software, DPDAK (directly programmable data analysis kit), is based on a plug-in structure and allows individual extension in accordance with the requirements of the user. The article demonstrates the use of DPDAK for on- and offline analysis of scanning small-angle X-ray scattering (SAXS) data on biological samples and microfluidic systems, as well as for a comprehensive analysis of grazing-incidence SAXS data. In addition to a comparison with existing software packages, the structure of DPDAK and the possibilities and limitations are discussed.

A new small-angle X-ray scattering set-up on the crystallography beamline I711 at MAX-lab

DEFF Research Database (Denmark)

Knaapila, M.; Svensson, C.; Barauskas, J.

2009-01-01

A small-angle X-ray scattering (SAXS) set-up has recently been developed at beamline I711 at the MAX II storage ring in Lund (Sweden). An overview of the required modifications is presented here together with a number of application examples. The accessible q range in a SAXS experiment is 0.009-0...

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)

Science.gov (United States)

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 X-ray scattering (SAXS) for metrological size determination of nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Gleber, Gudrun; Krumrey, Michael; Cibik, Levent; Marggraf, Stefanie; Mueller, Peter [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Hoell, Armin [Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin (Germany)

2011-07-01

To measure the size of nanoparticles, different measurement methods are available but their results are often not compatible. In the framework of an European metrology project we use Small-Angle X-ray Scattering (SAXS) to determine the size and size distribution of nanoparticles in aqueous solution, where the special challange is the traceability of the results. The experiments were performed at the Four-Crystal Monochromator (FCM) beamline in the laboratory of Physikalisch-Technische Bundesanstalt (PTB) at BESSY II using the SAXS setup of the Helmholtz-Zentrum Berlin (HZB). We measured different particles made of PMMA and gold in a diameter range of 200 nm down to about 10 nm. The aspects of traceability can be classified in two parts: the first is the experimental part with the uncertainties of distances, angles, and wavelength, the second is the part of analysis, with the uncertainty of the choice of the model used for fitting the data. In this talk we want to show the degree of uncertainty, which we reached in this work yet.

Time-slicing subsystem of the biology small-angle x-ray scattering station at the National Synchrotron Light Source

International Nuclear Information System (INIS)

Stubblefield, F.W.

1985-11-01

The time-slicing subsystem of the Biology Small-Angle X-ray Scattering divides the time period during which the data for small-angle x-ray diffraction patterns from biological samples is collected into time slices (or frames). The subsystem, being part of a multiprocessor experiment control and data acquisition system, has its own dedicated processor; it also has special-purpose front-end electronics sufficient to generate the gating and other control signals required to produce a sequence of as many as 256 time slices, measured with a basic time unit of 1 μsec. The electronics also synchronizes with execution of the time slice sequence the application of stimuli to the biological sample, the measurement of voltages generated by the sample, and the application of auxiliary device trigger pulses and routes detector data and auxiliary scaler data into appropriate time-slice-indexed buffers in a large external data memory array. The structure of the entire experiment control and data acquisition system is briefly reviewed. Details of the structure and operation of the time slice subsystem are presented. 7 refs., 5 figs

Identifying low and high density amorphous phases during zeolite amorphisation using small and wide angle X-ray scattering

International Nuclear Information System (INIS)

Meneau, F.; Greaves, G.N.

2005-01-01

In situ experiments following the thermal amorphisation of zeolites reveal massive increases in small angle X-ray scattering (SAXS), persisting well beyond the stage where wide angle X-ray scattering (WAXS) can detect that any crystalline phase is present. This heterogeneity in the amorphised phase is attributed to the transition from a low density amorphous phase (LDA) to a high density amorphous phase (HDA) at the glass transition. The fractions of zeolite, LDA and HDA phases obtained from SAXS analysis are discussed in the context of non-linear changes detected in 29 Si solid state NMR during zeolite amorphisation. Whilst the HDA phase is chemically disordered, the LDA phase exhibits much of the Al-Si ordering present in the starting zeolite. These findings are considered in the context of perfect glasses predicted to occur when super strong liquids are supercooled

Direct monitoring of calcium-triggered phase transitions in cubosomes using small-angle X-ray scattering combined with microfluidics

DEFF Research Database (Denmark)

Ghazal, Aghiad; Gontsarik, Mark; Kutter, Jörg P.

2016-01-01

This article introduces a simple microfluidic device that can be combined with synchrotron small-angle X-ray scattering (SAXS) for monitoring dynamic structural transitions. The microfluidic device is a thiol-ene-based system equipped with 125 µm-thick polystyrene windows, which are suitable for ....... The combination of microfluidics with X-ray techniques can be used for investigating protein unfolding, for monitoring the formation of nanoparticles in real time, and for other biomedical and pharmaceutical investigations.......-ray experiments. The device was prepared by soft lithography using elastomeric molds followed by a simple UV-initiated curing step to polymerize the chip material and simultaneously seal the device with the polystyrene windows. The microfluidic device was successfully used to explore the dynamics...

Ordered array of ω particles in β-Ti matrix studied by small-angle X-ray scattering

International Nuclear Information System (INIS)

Šmilauerová, J.; Harcuba, P.; Stráský, J.; Stráská, J.; Janeček, M.; Pospíšil, J.; Kužel, R.; Brunátová, T.; Holý, V.; Ilavský, J.

2014-01-01

Nanosized particles of ω phase in a β-Ti alloy were investigated by small-angle X-ray scattering using synchrotron radiation. We demonstrated that the particles are spontaneously weakly ordered in a three-dimensional cubic array along the 〈100〉-directions in the β-Ti matrix. The small-angle scattering data fit well to a three-dimensional short-range-order model; from the fit we determined the evolution of the mean particle size and mean distance between particles during ageing. The self-ordering of the particles is explained by elastic interaction between the particles, since the relative positions of the particles coincide with local minima of the interaction energy. We performed numerical Monte Carlo simulation of the particle ordering and we obtained a good agreement with the experimental data

Small angle X-ray scattering and transmission electron microscopy study of the Lactobacillus brevis S-layer protein

Energy Technology Data Exchange (ETDEWEB)

Jaeaeskelaeinen, Pentti [Department of Biomedical Engineering and Computational Science, PO Box 2200, FI-02015 Aalto University School of Science and Technology (Finland); Engelhardt, Peter [Haartman Institute, Department of Pathology, PO Box 21, FIN-00014 University of Helsinki (Finland); Hynoenen, Ulla; Palva, Airi [Department of Basic Veterinary Sciences, Division of Microbiology, FIN-00014 University of Helsinki (Finland); Torkkeli, Mika; Serimaa, Ritva, E-mail: ritva.serimaa@helsinki.f [Department of Physics, POB 64, 00014 University of Helsinki (Finland)

2010-10-01

The structure of self-assembly domain containing recombinant truncation mutants of Lactobacillus brevis surface layer protein SlpA in aqueous solution was studied using small-angle X-ray scattering and transmission electron microscopy. The proteins were found out to interact with each other forming stable globular oligomers of about 10 monomers. The maximum diameter of the oligomers varied between 75 A and 435 A.

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.

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.)

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

Analysis of the aggregation structure from amphiphilic block copolymers in solutions by small-angle x-ray scattering

CERN Document Server

Rong Li Xia; Wang Jun; Wei Liu He; Li Fu Mian; Li Zi Chen

2002-01-01

The aggregation structure of polystyrene-p vinyl benzoic amphiphilic block copolymers which were prepared in different conditions was investigated by synchrotron radiation small-angle x-ray scattering (SAXS). The micelle was self-assembled in selective solvents of the block copolymers. Authors' results demonstrate that the structure of the micelle depends on the factors, such as the composition of the copolymers, the nature of the solvent and the concentration of the solution

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)

Measuring helium bubble diameter distributions in tungsten with grazing incidence small angle x-ray scattering (GISAXS)

Science.gov (United States)

Thompson, M.; Kluth, P.; Doerner, R. P.; Kirby, N.; Riley, D.; Corr, C. S.

2016-02-01

Grazing incidence small angle x-ray scattering was performed on tungsten samples exposed to helium plasma in the MAGPIE and Pisces-A linear plasma devices to measure the size distributions of resulting helium nano-bubbles. Nano-bubbles were fitted assuming spheroidal particles and an exponential diameter distribution. These particles had mean diameters between 0.36 and 0.62 nm. Pisces-A exposed samples showed more complex patterns, which may suggest the formation of faceted nano-bubbles or nano-scale surface structures.

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.

Small angle x-ray studies reveal that Aspergillus niger glucoamylase has a defined extended conformation and can form dimers in solution

DEFF Research Database (Denmark)

Jørgensen, Anders Dysted; Nøhr, Jane; Kastrup, Jette Sandholm

2008-01-01

is poorly understood and structurally undescribed, and data regarding domain organization and intramolecular functional cooperativity are conflicting or non-comprehensive. Here, we report a combined small angle x-ray scattering and calorimetry study of Aspergillus niger glucoamylase 1, glucoamylase 2, which...

Determination of the thermodynamic state of concentrated hemoglobin solutions by means of small angle X-ray scattering

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)

Crystallization behavior of polyethylene on silicon wafers in solution casting processes traced by time-resolved measurements of synchrotron grazing-incidence small-angle and wide-angle X-ray scattering

International Nuclear Information System (INIS)

Sasaki, S; Masunaga, H; Takata, M; Itou, K; Tashiro, K; Okuda, H; Takahara, A

2009-01-01

Crystallization behavior of polyethylene (PE) on silicon wafers in solution casting processes has been successfully traced by time-resolved grazing-incidence small-angle and wide-angle X-ray scattering (GISWAXS) measurements utilizing synchrotron radiation. A p-xylene solution of PE kept at ca. 343 K was dropped on a silicon wafer at ca. 298 K. While the p-xylene evaporated naturally from the dropped solution sample, PE chains crystallized to be a thin film. Raman spectral measurements were performed simultaneously with the GISWAXS measurements to evaluate quantitatively the p-xylene the dropped solution contained. Grazing-incidence wide-angle X-ray scattering (GIWAXS) patterns indicated nucleation and crystal growth in the dropped solution and the following as-cast film. GIWAXS and Raman spectral data revealed that crystallization of PE was enhanced after complete evaporation of the p-xylene from the dropped solution. The [110] and [200] directions of the orthorhombic PE crystal became relatively parallel to the wafer surface with time, which implied that the flat-on lamellae with respect to the wafer surface were mainly formed in the as-cast film. On the other hand, grazing-incidence small-angle X-ray scattering (GISAXS) patterns implied formation of isolated lamellae in the dropped solution. The lamellae and amorphous might alternatively be stacked in the preferred direction perpendicular to the wafer surface. The synchrotron GISWAXS experimental method could be applied for kinetic study on hierarchical structure of polymer thin films.

Watching Nanoparticles Form: An In Situ (Small-/Wide-Angle X-ray Scattering/Total Scattering) Study of the Growth of Yttria-Stabilised Zirconia in Supercritical Fluids

DEFF Research Database (Denmark)

Tyrsted, Christoffer; Pauw, Brian; Jensen, Kirsten Marie Ørnsbjerg

2012-01-01

Understanding nanoparticle formation reactions requires multitechnique in situ characterisation, since no single characterisation technique provides adequate information. Here, the first combined small-angle X-ray scattering (SAXS)/wide-angle X-ray scattering (WAXS)/total-scattering study of nano...... of nanoparticle formation is presented. We report on the formation and growth of yttria-stabilised zirconia (YSZ) under the extreme conditions of supercritical methanol for particles with Y2O3 equivalent molar fractions of 0, 4, 8, 12 and 25%....

Morphological and structural characterization of PHBV/organoclay nanocomposites by small angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Carli, Larissa N., E-mail: lncarli@ucs.br [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves, 9500, Porto Alegre, 91501-970, RS (Brazil); Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, Rua Francisco Getulio Vargas, 1130, Caxias do Sul, 95070-560, RS (Brazil); Bianchi, Otavio, E-mail: obianchi@ucs.br [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, Rua Francisco Getulio Vargas, 1130, Caxias do Sul, 95070-560, RS (Brazil); Machado, Giovanna, E-mail: giovannamachado@uol.com.br [Centro de Tecnologias Estrategicas do Nordeste, Av. Prof. Luiz Freire, 01, Cidade Universitaria, Recife, 50740-540, PE (Brazil); Programa de Pos-Graduacao de Materiais, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego, 1235, Recife, 50670-901, PE (Brazil); Crespo, Janaina S., E-mail: jscrespo@ucs.br [Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, Rua Francisco Getulio Vargas, 1130, Caxias do Sul, 95070-560, RS (Brazil); Mauler, Raquel S., E-mail: raquel.mauler@ufrgs.br [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves, 9500, Porto Alegre, 91501-970, RS (Brazil)

2013-03-01

In this work, the morphological and structural behaviors of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanocomposites were investigated using small angle X-ray scattering (SAXS), wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). The nanocomposites with 1, 3 and 5 wt.% of organically modified montmorillonite Cloisite Registered-Sign 30B (OMMT) were prepared by melt processing in a twin screw extruder using two different processing conditions (low and high shear intensity). The lamellar long period of the polymer was lower for the nanocomposites, with high polydispersity values. However, the crystalline thickness increased with the clay content and was independent of the processing conditions. This behavior resulted in a high linear crystallinity of the nanocomposites with 3 and 5 wt.% OMMT. The disruption factor ({beta}) was in agreement with the WAXD and TEM findings, indicating a good dispersion of the nanoparticles in the PHBV matrix with 3 wt.% of OMMT during the high shear intensity of melt processing. Highlights: Black-Right-Pointing-Pointer SAXS was used for morphological and crystalline studies of PHBV/OMMT nanocomposites. Black-Right-Pointing-Pointer The crystalline structure was influenced by the presence of clay. Black-Right-Pointing-Pointer The degree of clay dispersion in a polymer matrix was quantified. Black-Right-Pointing-Pointer The morphology comprised exfoliated particles, nanoscale and microscale clusters. Black-Right-Pointing-Pointer The results obtained by SAXS agreed well with TEM and WAXD results.

Structural evolution of regenerated silk fibroin under shear: Combined wide- and small-angle x-ray scattering experiments using synchrotron radiation

International Nuclear Information System (INIS)

Rossle, Manfred; Panine, Pierre; Urban, Volker S.; Riekel, Christine

2004-01-01

The structural evolution of regenerated Bombyx mori silk fibroin during shearing with a Couette cell has been studied in situ by synchrotron radiation small- and wide-angle x-ray scattering techniques. An elongation of fibroin molecules was observed with increasing shear rate, followed by an aggregation phase. The aggregates were found to be amorphous with β-conformation according to infrared spectroscopy. Scanning x-ray microdiffraction with a 5 (micro)m beam on aggregated material, which had solidified in air, showed silk II reflections and a material with equatorial reflections close to the silk I structure reflections, but with strong differences in reflection intensities. This silk I type material shows up to two low-angle peaks suggesting the presence of water molecules that might be intercalated between hydrogen-bonded sheets.

Structural evolution of regenerated silk fibroin under shear: Combined wide- and small-angle x-ray scattering experiments using synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Rossle, Manfred [European Molecular Biology Laboratory (EMBL), France; Panine, Pierre [European Synchrotron Radiation Facility (ESRF); Urban, Volker S [ORNL; Riekel, Christine [European Synchrotron Radiation Facility (ESRF)

2004-04-01

The structural evolution of regenerated Bombyx mori silk fibroin during shearing with a Couette cell has been studied in situ by synchrotron radiation small- and wide-angle x-ray scattering techniques. An elongation of fibroin molecules was observed with increasing shear rate, followed by an aggregation phase. The aggregates were found to be amorphous with {beta}-conformation according to infrared spectroscopy. Scanning x-ray microdiffraction with a 5 {micro}m beam on aggregated material, which had solidified in air, showed silk II reflections and a material with equatorial reflections close to the silk I structure reflections, but with strong differences in reflection intensities. This silk I type material shows up to two low-angle peaks suggesting the presence of water molecules that might be intercalated between hydrogen-bonded sheets.

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

Pepsi-SAXS : an adaptive method for rapid and accurate computation of small-angle X-ray scattering profiles

OpenAIRE

Grudinin , Sergei; Garkavenko , Maria; Kazennov , Andrei

2017-01-01

International audience; A new method called Pepsi-SAXS is presented that calculates small-angle X-ray scattering profiles from atomistic models. The method is based on the multipole expansion scheme and is significantly faster compared with other tested methods. In particular, using the Nyquist–Shannon–Kotelnikov sampling theorem, the multipole expansion order is adapted to the size of the model and the resolution of the experimental data. It is argued that by using the adaptive expansion ord...

Measurement of illite particle thickness using a direct Fourier transform of small-angle X-ray scattering data

Science.gov (United States)

Shang, Chao; Rice, James A.; Eberl, Dennis D.; Lin, Jar-Shyong

2003-01-01

It has been suggested that interstratified illite-smectite (I-S) minerals are composed of aggregates of fundamental particles. Many attempts have been made to measure the thickness of such fundamental particles, but each of the methods used suffers from its own limitations and uncertainties. Small-angle X-ray scattering (SAXS) can be used to measure the thickness of particles that scatter X-rays coherently. We used SAXS to study suspensions of Na-rectorite and other illites with varying proportions of smectite. The scattering intensity (I) was recorded as a function of the scattering vector, q = (4 /) sin(/2), where  is the X-ray wavelength and  is the scattering angle. The experimental data were treated with a direct Fourier transform to obtain the pair distance distribution function (PDDF) that was then used to determine the thickness of illite particles. The Guinier and Porod extrapolations were used to obtain the scattering intensity beyond the experimental q, and the effects of such extrapolations on the PDDF were examined. The thickness of independent rectorite particles (used as a reference mineral) is 18.3 Å. The SAXS results are compared with those obtained by X-ray diffraction peak broadening methods. It was found that the power-law exponent (α) obtained by fitting the data in the region of q = 0.1-0.6 nm-1 to the power law (I = I0q-α) is a linear function of illite particle thickness. Therefore, illite particle thickness could be predicted by the linear relationship as long as the thickness is within the limit where α <4.0.

Penetration route of functional molecules in stratum corneum studied by time-resolved small- and wide-angle x-ray diffraction

International Nuclear Information System (INIS)

Hatta, Ichiro; Ohta, Noboru; Yagi, Naoto; Nakazawa, Hiromitsu; Obata, Yasuko; Inoue, Katsuaki

2011-01-01

We studied effects of functional molecules on corneocytes in stratum corneum using time-resolved small- and wide-angle x-ray diffraction after applying a functional molecule. From these results it was revealed that in the stratum corneum a typical hydrophilic molecule, ethanol, penetrates via the transcellular route and on the other hand a typical hydrophobic molecule, d-limonene, penetrates via the intercellular route.

Application of focused-beam flat-sample method to synchrotron powder X-ray diffraction with anomalous scattering effect

International Nuclear Information System (INIS)

Tanaka, M; Katsuya, Y; Matsushita, Y

2013-01-01

The focused-beam flat-sample method (FFM), which is a method for high-resolution and rapid synchrotron X-ray powder diffraction measurements by combination of beam focusing optics, a flat shape sample and an area detector, was applied for diffraction experiments with anomalous scattering effect. The advantages of FFM for anomalous diffraction were absorption correction without approximation, rapid data collection by an area detector and good signal-to-noise ratio data by focusing optics. In the X-ray diffraction experiments of CoFe 2 O 4 and Fe 3 O 4 (By FFM) using X-rays near the Fe K absorption edge, the anomalous scattering effect between Fe/Co or Fe 2+ /Fe 3+ can be clearly detected, due to the change of diffraction intensity. The change of observed diffraction intensity as the incident X-ray energy was consistent with the calculation. The FFM is expected to be a method for anomalous powder diffraction.

Tiny Tremors to Titanic Explosions: Tackling Transients in Anomalous X-Ray Pulsars

Science.gov (United States)

Kaspi, Victoria

We are requesting the target-of-oppurtunity (ToO) component of an ongoing, successful, long-term RXTE monitoring campaign of anomalous X- ray pulsars (AXPs). Their nature had been a mystery, but with our discoveries of X-ray bursts from AXPs, there is compelling evidence that they are young, isolated, ultra-magnetized neutron stars or "magnetars." We request ToO observations of any of the known and candidate AXPs as well as of any newly discovered AXPs should they exhibit anomalous behavior of one or more of the following types: bursts, significant sudden pulse profile changes, glitches or other rotational anomalies, or pulse fractions changes. These observations will allow us to answer basic physical questions about neutron star structure.

TINY HICCUPS TO TITANIC EXPLOSIONS: Tackling Transients in Anomalous X-ray Pulsars

Science.gov (United States)

Kaspi, Victoria

2011-09-01

The past decade has seen major progress in neutron star astrophysics, with the discovery of magnetars in general, and the recognition that the Anomalous X-ray Pulsars (AXPs) fall in this class. AXPs have recently revealed surprising and dramatic variability behavior, which theorists have begun to show are highly constraining of physical models of magnetars, including their crusts, atmospheres, coronae and magnetospheres. In this proposal, we request Chandra/ACIS-S Target-of-Opportunity observations of one major Anomalous X-ray Pulsar (AXP) outburst in AO13, in order to study in detail the evolution of the spectrum, pulsed fraction and pulse profile, for quantitative confrontation with recently developed models for the structure and electrodynamics of magnetars.

Small-angle X-ray-scattering investigation and structural-model study of the fatty-acid synthetase from pig liver

International Nuclear Information System (INIS)

Folkhard, W.; Felser, B.; Pilz, I.; Kratky, O.; Dutler, H.; Vogel, H.

1977-01-01

The structure of the fatty acid synthetase from pig liver was studied on models based upon structural and functional properties selected from pertinent results available from numerous investigations carried out with fatty acid synthetase from this and other sources. When comparing small-angle X-ray-scattering curves calculated with these models and curves obtained from small-angle X-ray-scattering experiments carried out with the pig-liver enzyme, we tried to select a model which would lead to an acceptable correlation between the calculated and the experimental curves and at the same time fulfil the known structural and the functional requirements. The comparison of the curves was started with a model of low complexity. The observed discrepancy, together with arguments from the structural and the functional properties, helped decide which is the next most reasonable model to be considered. This procedure was repeated for five models of increasing complexity. In the model which led to the best fit the multienzyme complex is composed of two halves in an asymmetric conformation including hollow spaces. This highly anisotropic model would imply that the two halves change their conformation each time a synthetic cycle is completed and that the growing fatty acid is handed over from one half to the other. (orig.) [de

Combined in situ small and wide angle X-ray scattering studies of TiO2 nano-particle annealing to 1023 K

DEFF Research Database (Denmark)

Kehres, Jan; Andreasen, Jens Wenzel; Krebs, Frederik C

2010-01-01

Combined in situ small- and wide-angle X-ray scattering (SAXS/WAXS) studies were performed in a recently developed laboratory setup to investigate the dynamical properties of dry oleic acid-capped titanium dioxide nanorods during annealing in an inert gas stream in a temperature interval of 298-1...

Synchrotron small-angle x-ray scattering investigation on integral membrane protein light-harvesting complex LH2 from photosynthetic bacterium rhodopseudomonas acidophila

International Nuclear Information System (INIS)

Du Luchao; Weng Yuxiang; Hong Xinguo; Xian Dingchang; Kobayashi Katsumi

2006-01-01

Structures of membrane protein in solution are different from that in crystal phase. We present the primary results of small angle x-ray scattering (SAXS) resolved topological structures of a light harvesting antenna membrane protein complex LH2 from photosynthetic bacteria Rhodopseudomonas acidophila in detergent solution for the first time. Our results show that the elliptical shape of the LH2 complex in solution clearly deviates from its circular structure in crystal phase determined by x-ray diffraction. This result provides an insight into the structure and function interplay in LH2. (authors)

Angle dependent focal spot size of a conical X-ray target

International Nuclear Information System (INIS)

Saeed Raza, Hamid; Jin Kim, Hyun; Nam Kim, Hyun; Oh Cho, Sung

2015-01-01

Misaligned phantoms may severely affect the focal spot calculations. A method is proposed to determine the geometry of the X-ray target and the position of the image radiograph around the X-ray target to get a relatively smaller focal spot size. Results reveal that the focal spot size is not always isotropic around the target but it decreases as the point of observation shifts radially away from the center line of the conical X-ray target. This research will help in producing high quality X-ray images in multi-directions by properly aligning the phantoms and the radiograph tallies. - Highlights: • Misaligned phantoms may severely affect the focal spot calculations. • The aim of this research is to analyze systematically the angle dependent behavior of the focal spot size around a conical shaped X-ray target. • A general purpose Monte Carlo (MCNP5) computer code is used to achieve a relatively small focal spot size. • Angular distribution of the X-ray focal spot size mainly depends on the angular orientation of the phantom and its aligned FIR tally. • This research will help in producing high quality X-ray images in multi-directions

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.

Quantification of RNA in bacteriophage MS2-like viruses in solution by small-angle X-ray scattering

International Nuclear Information System (INIS)

Kuzmanovic, Deborah A.; Elashvili, Ilya; Wick, Charles; O'Connell, Catherine; Krueger, Susan

2006-01-01

Recombinant forms of bacteriophage MS2 virus particles, wild-type MS2 and MS2 capsids have been examined in solution using small-angle X-ray scattering (SAXS). SAXS was used to determine the overall size of the virus particles and to quantify the amount of encapsulated viral RNA. These studies show that analysis of natural and recombinant forms of MS2 virus by SAXS can be used as both a quantitative measure of nucleic acid content in situ and diagnostic indicator of sample integrity

Particle-scale structure in frozen colloidal suspensions from small-angle x-ray scattering

KAUST Repository

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.

Particle-scale structure in frozen colloidal suspensions from small-angle x-ray scattering

KAUST Repository

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.

Characterization of Nanocellulose Using Small-Angle Neutron, X-ray, and Dynamic Light Scattering Techniques.

Science.gov (United States)

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.

Study on the structure of Fe sub 2 O sub 3 xerogels by small angle X-ray scattering

CERN Document Server

Liu Yi; Zhao Xin; Yang Tong Hua; Zhao Hui; Rong Li Xia; Zhang Jing; Wang Jun; Dong Bao Zhong

2002-01-01

Small angle X-ray scattering (SAXS) with synchrotron radiation as X-ray source is used to study the pore structure of Fe sub 2 O sub 3 xerogels prepared by sol-gel procedure and then heat-treated at different temperatures. By analysing the distribution of diameters of the pores, specific surfaces and fractal behaviors in samples, the characters and mechanisms of pores growing are discussed. The results show that the pores in Fe sub 2 O sub 3 xerogels are polydisperse and the structure of the pores is mass fractal. With increase in heat-treatment temperature, the average size of diameters of the pores and the dimension of fractal of Fe sub 2 O sub 3 xerogels are increased, whereas the scale range possessing fractal behavior become narrow

Formation process of hierarchical structures in crystalline polymers as analyzed by simultaneous measurements of small-angle X-ray scattering and other techniques

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)

Corrections of residual fluorescence distortions for a glancing-emergence-angle x-ray-absorption technique

International Nuclear Information System (INIS)

Brewe, D.L.; Pease, D.M.; Budnick, J.I.

1994-01-01

Distortions appear in x-ray-absorption spectra obtained by monitoring the fluorescence from thick samples with concentrated absorbing species. The glancing-emergence-angle technique for obtaining spectra from this type of sample eliminates distortions from the measured spectra by monitoring the fluorescence leaving the sample at a small angle relative to the sample surface. This technique is limited by the small signal available from the inherently limited detector solid angle. In addition, no precise estimate of the required restriction on maximum emergent angle θ max has been available. We have calculated residual extended x-ray-absorption fine structure distortions as a function of θ max , and performed experimental tests of the calculations. These calculations provide a means to estimate the required detector geometry for negligible distortions, or alternatively, allow the use of a larger θ max , increasing the available signal, with the remaining residual distortions removed by application of the calculations. The calculations are also applicable to other detector geometries, and account for detectors subtending a large solid angle by an integration over the subtended angle. This represents an improvement over previous calculations. The application to more general detector configurations is also discussed

Small angle X-ray scattering study on the conformation of polystyrene in the anti-solvent process of supercritical fluids

International Nuclear Information System (INIS)

Liu Yi; Wang Hongli; Zhao Xin; Chen Na; Li Dan; Liu Zhimin; Han Buxing; Rong Lixia; Zhao Hui; Wang Jun; Dong Baozhong

2003-01-01

The conformation of polystyrene in the anti-solvent process of supercritical fluids (compressed CO 2 + polystyrene + tetrahydrofuran) is studied by synchrotron radiation X-ray small angle scattering (SAXS). Coil-to-globule transform of polystyrene chain is observed with increasing the concentration of CO 2 . It is found that polystyrene coils at the pressure lower than cloud point pressure (p c ) and changes into globule with uniform density at the pressure higher than p c

An apparatus for high speed measurements of small-angle x-ray scattering profiles with a linear position sensitive detector

International Nuclear Information System (INIS)

Hashimoto, Takeji; Suehiro, Shoji; Shibayama, Mitsuhiro; Saijo, Kenji; Kawai, Hiromichi

1981-01-01

An apparatus for high speed measurements of small-angle X-ray scattering (SAXS) is described. This apparatus utilizes a 12 kW rotating anode X-ray generator, a linear position sensitive proportional counter (multicathode delay line PSPC), and a two-parameter multichannel pulse height analyzer (MCA) with 12 kwords (16 bits/word) memory area available for SAXA intensity data as a function of position (scattering angles) and time slice. The two-parameter MCA is constructed within a microcomputer system, by utilizing its R/W memory for data storage, and the memory incrementing and real-time CRT display is implemented by using two direct memory access (DMA) controllers. The cycle time of the access is about 10 μs. The measuring time for SAXS profiles with this apparatus can be shortened approximately by three orders of magnitude in comparison with the measuring time with SAXS apparatuses utilizing a conventional step-scanning goniometer and a conventional X-ray tube, thus permitting time-resolved analyses of SAXS profiles. Some applications of the apparatus to dynamic SAXS measurements are presented for polymeric systems, the preliminary results of which seem to indicate the possibility of obtaining a new class of data on dynamics in structural transformation, deformation, formation and annihilation in the scale of a few tens to several hundred Angstroms. (author)

Study of change in dispersion and orientation of clay platelets in a polymer nanocomposite during tensile test by variostage small-angle X-ray scattering

CSIR Research Space (South Africa)

Bandyopadhyay, J

2012-04-01

Full Text Available To understand the change in dispersion and orientation of clay platelets in three-dimensional space during tensile test, neat polymer and its nanocomposite samples were studied by small- and wide-angle X-ray scattering (SWAXS). The samples after...

Glancing angle x-ray studies of oxide films

International Nuclear Information System (INIS)

Davenport, A.J.; Isaacs, H.S.

1989-01-01

High brightness synchrotron radiation incident at glancing angles has been used to study inhibiting species present in low concentrations in oxide films on aluminum. Glancing incident angle fluorescence measurements give surface-sensitive information on the valence state of elements from the shape of the x-ray absorption edge. Angle-resolved measurements show the depth distribution of the species present. 15 refs., 4 figs

Antibodies under pressure: A Small-Angle X-ray Scattering study of Immunoglobulin G under high hydrostatic pressure.

Science.gov (United States)

König, Nico; Paulus, Michael; Julius, Karin; Schulze, Julian; Voetz, Matthias; Tolan, Metin

2017-12-01

In the present work two subclasses of the human antibody Immunoglobulin G (IgG) have been investigated by Small-Angle X-ray Scattering under high hydrostatic pressures up to 5kbar. It is shown that IgG adopts a symmetric T-shape in solution which differs significantly from available crystal structures. Moreover, high-pressure experiments verify the high stability of the IgG molecule. It is not unfolded by hydrostatic pressures of up to 5kbar but a slight increase of the radius of gyration was observed at elevated pressures. Copyright © 2017 Elsevier B.V. All rights reserved.

Small-angle X-ray scattering on growth of AgCl crystallites in photochromic glasses

International Nuclear Information System (INIS)

Takatohi, U.E.; Bittencourt, D.R.S.; Watanabe, S.

1997-01-01

Reversible changes in the optical properties of photochromic glasses are observed owing to the presence of small silver halide crystals inside the glassy matrix. These crystals grow during the glass heat-treatment processing. Samples with molar composition of 40SiO 2 .10Al 2 O 3 .16.1K 2 O.33.9B 2 O 3 , doped with AgCl and CuO, were produced and submitted to different heat treatments: (i) for 0.5 h at temperatures from 753 to 893 K and (ii) at 873 K for periods of time from 0.25 to 1.25 h. Small-angle X-ray scattering (SAXS) was used to characterize the samples. The samples heat treated between 843 and 893 K presented an increasing growth rate of the Guinier radius (R g ). Samples heat treated at a fixed temperature of 873 K and different time t showed a law R g 3 = kt + c. Variations in the optical absorbance at 280 nm and the additional absorbance spectra of samples exposed to light showed correlation with the SAXS results. (orig.)

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.)

Laser ablation and injection moulding as techniques for producing micro channels compatible with Small Angle X-Ray Scattering

DEFF Research Database (Denmark)

Haider, R.; Marmiroli, B.; Gavalas, I.

2018-01-01

Microfluidic mixing is an important means for in-situ sample preparation and handling while Small Angle X-Ray Scattering (SAXS) is a proven tool for characterising (macro-)molecular structures. In combination those two techniques enable investigations of fast reactions with high time resolution......, the requirement for low scattering especially limits the techniques suitable for producing the mixer, as the fabrication process can induce molecular orientations and stresses that can adversely influence the scattering signal. Not only is it important to find a production method that results in a device with low...

Application of a one-dimensional position-sensitive detector to a Kratky small-angle x-ray camera

International Nuclear Information System (INIS)

Russell, T.P.; Stein, R.S.; Kopp, M.K.; Zedler, R.E.; Hendricks, R.W.; Lin, J.S.

1979-01-01

A conventional Kratky small-angle collimation system has been modified to allow the use of a one-dimensional position-sensitive x-ray detector. The detector was designed specifically for use with a long-slit camera and has uniform sensitivity over the entire beam in the slit-length direction. Procedures for alignment of the collimation system are given, and a variety of tests of the performance of the system are presented. Among the latter are measurements of electronic noise and parasitic scattering as well as comparisons against samples which were also measured on other cameras. The good agreement of these comparisons demonstrates the success of the use of a position-sensitive detector with the Kratky collimation system

Application of a one-dimensional position-sensitive detector to a Kratky small-angle x-ray camera

Energy Technology Data Exchange (ETDEWEB)

Russell, T.P.; Stein, R.S.; Kopp, M.K.; Zedler, R.E.; Hendricks, R.W.; Lin, J.S.

1979-01-01

A conventional Kratky small-angle collimation system has been modified to allow the use of a one-dimensional position-sensitive x-ray detector. The detector was designed specifically for use with a long-slit camera and has uniform sensitivity over the entire beam in the slit-length direction. Procedures for alignment of the collimation system are given, and a variety of tests of the performance of the system are presented. Among the latter are measurements of electronic noise and parasitic scattering as well as comparisons against samples which were also measured on other cameras. The good agreement of these comparisons demonstrates the success of the use of a position-sensitive detector with the Kratky collimation system.

Tiny Tremors to Titanic Explosions: Tackling Transients in Anomalous X-Ray Pulsars (core Program)

Science.gov (United States)

We are requesting the target-of-oppurtunity (ToO) component of an ongoing, successful, long-term RXTE monitoring campaign of anomalous X- ray pulsars (AXPs). Their nature had been a mystery, but with our discoveries of X-ray bursts from AXPs, there is compelling evidence that they are young, isolated, ultra-magnetized neutron stars or "magnetars." We request ToO observations of any of the known and candidate AXPs as well as of any newly discovered AXPs should they exhibit anomalous behavior of one or more of the following types: bursts, significant sudden pulse profile changes, glitches or other rotational anomalies, or pulse fractions changes. These observations will allow us to answer basic physical questions about neutron star structure.

Effect of Cobalt Fillers on Polyurethane Segmentations Investigated by Synchrotron Small Angle X-Ray Scattering

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.

A Mo-anode-based in-house source for small-angle X-ray scattering measurements of biological macromolecules

Energy Technology Data Exchange (ETDEWEB)

Bruetzel, Linda K.; Fischer, Stefan; Salditt, Annalena; Sedlak, Steffen M.; Nickel, Bert; Lipfert, Jan, E-mail: Jan.Lipfert@lmu.de [Department of Physics, Nanosystems Initiative Munich, and Center for Nanoscience, Ludwig-Maximilians-University Munich, Amalienstr. 54, 80799 Munich, Germany and Geschwister-Scholl Platz 1, 80539 Munich (Germany)

2016-02-15

We demonstrate the use of a molybdenum-anode-based in-house small-angle X-ray scattering (SAXS) setup to study biological macromolecules in solution. Our system consists of a microfocus X-ray tube delivering a highly collimated flux of 2.5 × 10{sup 6} photons/s at a beam size of 1.2 × 1.2 mm{sup 2} at the collimation path exit and a maximum beam divergence of 0.16 mrad. The resulting observable scattering vectors q are in the range of 0.38 Å{sup −1} down to 0.009 Å{sup −1} in SAXS configuration and of 0.26 Å{sup −1} up to 5.7 Å{sup −1} in wide-angle X-ray scattering (WAXS) mode. To determine the capabilities of the instrument, we collected SAXS data on weakly scattering biological macromolecules including proteins and a nucleic acid sample with molecular weights varying from ∼12 to 69 kDa and concentrations of 1.5–24 mg/ml. The measured scattering data display a high signal-to-noise ratio up to q-values of ∼0.2 Å{sup −1} allowing for an accurate structural characterization of the samples. Moreover, the in-house source data are of sufficient quality to perform ab initio 3D structure reconstructions that are in excellent agreement with the available crystallographic structures. In addition, measurements for the detergent decyl-maltoside show that the setup can be used to determine the size, shape, and interactions (as characterized by the second virial coefficient) of detergent micelles. This demonstrates that the use of a Mo-anode based in-house source is sufficient to determine basic geometric parameters and 3D shapes of biomolecules and presents a viable alternative to valuable beam time at third generation synchrotron sources.

Thin disk models of Anomalous X-ray Pulsars

Energy Technology Data Exchange (ETDEWEB)

Yavuz Eksi, K.; Ali Alpar, M

2004-06-01

We discuss the options of the fall-back disk model of Anomalous X-Ray Pulsars (AXPs). We argue that the power-law index of the mass inflow rate during the propeller stage can be lower than those employed in earlier models. We take into account the effect of the super-critical mass inflow at the earliest stages on the inner radius of the disk and argue that the system starts as a propeller. Our results show that, assuming a fraction of the mass inflow is accreted onto the neutron star, the fall-back disk scenario can produce AXPs for acceptable parameters.

Six-dimensional real and reciprocal space small-angle X-ray scattering tomography.

Science.gov (United States)

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.

In situ grazing incidence small-angle X-ray scattering investigation of polystyrene nanoparticle spray deposition onto silicon.

Science.gov (United States)

Herzog, Gerd; Benecke, Gunthard; Buffet, Adeline; Heidmann, Berit; Perlich, Jan; Risch, Johannes F H; Santoro, Gonzalo; Schwartzkopf, Matthias; Yu, Shun; Wurth, Wilfried; Roth, Stephan V

2013-09-10

We investigated the spray deposition and subsequent self-assembly during drying of a polystyrene nanoparticle dispersion with in situ grazing incidence small-angle X-ray scattering at high time resolution. During the fast deposition of the dispersion and the subsequent evaporation of the solvent, different transient stages of nanoparticle assembly can be identified. In the first stage, the solvent starts to evaporate without ordering of the nanoparticles. During the second stage, large-scale structures imposed by the breakup of the liquid film are observable. In this stage, the solvent evaporates further and nanoparticle ordering starts. In the late third drying stage, the nanoparticles self-assemble into the final layer structure.

Low-angle X-ray scattering from spices

International Nuclear Information System (INIS)

Desouky, O.S.; Ashour, Ahmed H.; Abdullah, Mohamed I.; Elshemey, Wael M.

2002-01-01

Low-angle scattering of X-rays is characterized by the presence of one or more peaks in the forward direction of scattering. These peaks are due to the interference of photons coherently scattered from the molecules of the medium. Thus these patterns are closely linked to the molecular structure of the investigated medium. In this work, low-angle X-ray scattering (LAXS) profiles of five spices; pimpinella anisum (anise), coriandrum sativum (coriander), cuminum cyminum (cumin), foenculum vulgare (fennel) and nigella sativa (nigella or black cumin) are presented after extensive measurements. It is found that all spices exhibit one characteristic peak at a scattering angle around 10 deg. This is equivalent to a value x=0.0565 A -1 , where x=sin(θ/2)/λ. The full width at half maximum (FWHM) of this peak is found to be characteristic for each type of the investigated spices. The possibility to detect the irradiation of these spices from their LAXS profiles is also examined after 10, 20, 30 and 40 kGy doses of gamma radiation. Except for anise, coriander and cumin at 40 kGy, there are no detectable deviations from the control samples in the scattering profiles of irradiated samples. These results comply with the recommendations of the FDA (US Food and Drug Administration) which defines 30 kGy as the maximum dose for irradiation of spices. The present technique could be used to detect over-irradiation, which causes damage to the molecular structure of some spices

Combining Single-Molecule Optical Trapping and Small-Angle X-Ray Scattering Measurements to Compute the Persistence Length of a Protein ER/K alpha-Helix

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 X-ray scattering on growth of AgCl crystallites in photochromic glasses

Energy Technology Data Exchange (ETDEWEB)

Takatohi, U.E. [Inst. Adventista de Ensino, Sao Paulo (Brazil); Bittencourt, D.R.S.; Watanabe, S.

1997-10-01

Reversible changes in the optical properties of photochromic glasses are observed owing to the presence of small silver halide crystals inside the glassy matrix. These crystals grow during the glass heat-treatment processing. Samples with molar composition of 40SiO{sub 2}.10Al{sub 2}O{sub 3}.16.1K{sub 2}O.33.9B{sub 2}O{sub 3}, doped with AgCl and CuO, were produced and submitted to different heat treatments: (i) for 0.5 h at temperatures from 753 to 893 K and (ii) at 873 K for periods of time from 0.25 to 1.25 h. Small-angle X-ray scattering (SAXS) was used to characterize the samples. The samples heat treated between 843 and 893 K presented an increasing growth rate of the Guinier radius (R{sub g}). Samples heat treated at a fixed temperature of 873 K and different time t showed a law R{sub g}{sup 3} = kt + c. Variations in the optical absorbance at 280 nm and the additional absorbance spectra of samples exposed to light showed correlation with the SAXS results. (orig.). 16 refs.

Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy and ultra-small angle X-ray scattering experiments

CERN Document Server

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).

Anomalous compression behaviour in Nd2O3 studied by x-ray diffraction and Raman spectroscopy

Directory of Open Access Journals (Sweden)

Sheng Jiang

2018-02-01

Full Text Available The structural stability of hexagonal Nd2O3 under pressure has been investigated by in situ synchrotron angle dispersive x-ray diffraction and Raman spectroscopy up to 53.1 GPa and 37.0 GPa, respectively. Rietveld analysis of the x-ray diffraction data indicate that the hexagonal Nd2O3 undergoes an isostructural phase transition in the pressure range from 10.2 to 20.3 GPa, accompanied by anomalous lattice compressibility and pressure-volume curve. A third-order Birch-Murnaghan fit based on the observed Pressure-Volume data yields zero pressure bulk moduli (B0 of 142(4 and 183(6 GPa for the low and high pressure hexagonal phases, respectively. Raman spectroscopy confirms this isostructural transition, the pressure dependence of the Raman modes display noticeable breaks in the pressure range of 9.7-20.9 GPa, which is consistent with the change of Nd-O bond length. The pressure coefficients of Raman peaks and the mode Grüneisen parameters of different Raman modes were also determined.

Structural features of various kinds of carbon fibers as determined by small-angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Li, Denghua; Du, Sujun [Shanxi Transportation Research Institute, National and Local Joint Engineering Laboratory of Advanced Road Materials, Taiyuan (China); Lu, Chunxiang; Wu, Gangping; Yang, Yu; Wang, Lina [Chinese Academy of Sciences, National Engineering Laboratory for Carbon Fiber Technology, Institute of Coal Chemistry, Taiyuan (China)

2016-11-15

The structural features of polyacrylonitrile and pitch-based carbon fibers were analyzed from a comprehensive point of view by X-ray measurements and related techniques. The results indicated that the undulating graphite ribbon with embedded microvoid was the main structural unit for graphitic fibers. The void's parameters for these fibers could be obtained directly by small-angle X-ray scattering following the classic method deduced based on the typical two-phase system (i.e., Porod's law, Guinier's law and Debye's law). The non-graphitic fibers, however, were composed of two-dimensional turbostratic crystallites in the aggregation of microfibril and thus had a quasi two-phase structure (microfibril, interfibrillar amorphous structure and microvoid embedded within the microfibril). The extended Debye or Beaucage model in this case should be applied in order to obtain the structural parameters. It also revealed that the quasi two-phase system would complete its transformation to two-phase system during high-temperature graphitization. Therefore, the degree of graphitization was speculated to be the essential indicator distinguishing graphitic fibers from non-graphitic ones and would be helpful in understanding the transformation of structural features during the graphitization of carbon fibers. (orig.)

X-ray magnetic circular dichroism and small angle neutron scattering studies of thiol capped gold nanoparticles

International Nuclear Information System (INIS)

de la Venta, J.; Bouzas, V.; Pucci, A.; Laguna-Marco, M.A.; Haskel, D.; te Velthuis, S.G.E; Hoffmann, A.; Lal, J.; Bleuel, M.; Ruggeri, G.; de Julian Fernandez, C.; Garcia, M.A.

2009-01-01

X-ray magnetic circular dichroism (XMCD) and Small Angle Neutron Scattering (SANS) measurements were performed on thiol capped Au nanoparticles (NPs) embedded into polyethylene. An XMCD signal of 0.8 · 10 -4 was found at the Au L 3 edge of thiol capped Au NPs embedded in a polyethylene matrix for which Superconducting Quantum Interference Device (SQUID) magnetometry yielded a saturation magnetization, M s , of 0.06 emu/g Au . SANS measurements showed that the 3.2 nm average-diameter nanoparticles are 28% polydispersed, but no detectable SANS magnetic signal was found with the resolution and sensitivity accessible with the neutron experiment. A comparison with previous experiments carried out on Au NPs and multilayers, yield to different values between XMCD signals and magnetization measured by SQUID magnetometer. We discuss the origin of those differences

An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

KAUST Repository

Sibillano, T.

2014-11-10

The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes\\' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

KAUST Repository

Sibillano, T.; De Caro, L.; Altamura, D.; Siliqi, D.; Ramella, M.; Boccafoschi, F.; Ciasca, G.; Campi, G.; Tirinato, Luca; Di Fabrizio, Enzo M.; Giannini, C.

2014-01-01

The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

Science.gov (United States)

Sibillano, T.; de Caro, L.; Altamura, D.; Siliqi, D.; Ramella, M.; Boccafoschi, F.; Ciasca, G.; Campi, G.; Tirinato, L.; di Fabrizio, E.; Giannini, C.

2014-11-01

The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

Crystal Structures and Small-angle X-ray Scattering Analysis of UDP-galactopyranose Mutase from the Pathogenic Fungus Aspergillus fumigatus

Energy Technology Data Exchange (ETDEWEB)

Dhatwalia, Richa; Singh, Harkewal; Oppenheimer, Michelle; Karr, Dale B.; Nix, Jay C.; Sobrado, Pablo; Tanner, John J. (LBNL); (Missouri); (VPI)

2015-10-15

UDP-galactopyranose mutase (UGM) is a flavoenzyme that catalyzes the conversion of UDP-galactopyranose to UDP-galactofuranose, which is a central reaction in galactofuranose biosynthesis. Galactofuranose has never been found in humans but is an essential building block of the cell wall and extracellular matrix of many bacteria, fungi, and protozoa. The importance of UGM for the viability of many pathogens and its absence in humans make UGM a potential drug target. Here we report the first crystal structures and small-angle x-ray scattering data for UGM from the fungus Aspergillus fumigatus, the causative agent of aspergillosis. The structures reveal that Aspergillus UGM has several extra secondary and tertiary structural elements that are not found in bacterial UGMs yet are important for substrate recognition and oligomerization. Small-angle x-ray scattering data show that Aspergillus UGM forms a tetramer in solution, which is unprecedented for UGMs. The binding of UDP or the substrate induces profound conformational changes in the enzyme. Two loops on opposite sides of the active site move toward each other by over 10 {angstrom} to cover the substrate and create a closed active site. The degree of substrate-induced conformational change exceeds that of bacterial UGMs and is a direct consequence of the unique quaternary structure of Aspergillus UGM. Galactopyranose binds at the re face of the FAD isoalloxazine with the anomeric carbon atom poised for nucleophilic attack by the FAD N5 atom. The structural data provide new insight into substrate recognition and the catalytic mechanism and thus will aid inhibitor design.

Small scale soft x-ray lasers

International Nuclear Information System (INIS)

Skinner, C.H.; DiCicco, D.S.; Kim, D.; Voorhees, D.; Suckewer, S.

1990-01-01

The widespread application of soft x-ray laser technology is contingent on the development of small scale soft x-ray lasers that do not require large laser facilities. Progress in the development of soft x-ray lasers pumped by a Nd laser of energy 6-12J is reported below. Application of an existing soft x-ray laser to x-ray microscopy has begun. A soft x-ray laser of output energy 1-3 mJ at 18,2 nm has been used to record high resolution images of biological specimens. The contact images were recorded on photoresist which was later viewed in a scanning electron microscope. The authors present a composite optical x-ray laser microscope design

Anomalous X-ray diffraction from self-assembled PbSe/PbEuTe quantum dots

International Nuclear Information System (INIS)

Holy, V.; Schuelli, T.U.; Lechner, R.T.; Springholz, G.; Bauer, G.

2005-01-01

Anomalous X-ray scattering from self-assembled PbSe quantum dots embedded in Pb 1-x Eu x Te was used for the study of their structure. The measured reciprocal-space distributions of diffracted intensity were compared with simulations based on kinematical scattering theory and continuum elasticity. From the comparison, the mean chemical composition of the dots and their aspect ratio (height/width) were estimated

Topological investigation of electronic silicon nanoparticulate aggregates using ultra-small-angle X-ray scattering

International Nuclear Information System (INIS)

Jonah, E. O.; Britton, D. T.; Beaucage, P.; Rai, D. K.; Beaucage, G.; Magunje, B.; Ilavsky, J.; Scriba, M. R.; Härting, M.

2012-01-01

The network topology of two types of silicon nanoparticles, produced by high energy milling and pyrolysis of silane, in layers deposited from inks on permeable and impermeable substrates has been quantitatively characterized using ultra-small-angle X-ray scattering, supported by scanning electron microscopy observations. The milled particles with a highly polydisperse size distribution form agglomerates, which in turn cluster to form larger aggregates with a very high degree of aggregation. Smaller nanoparticles with less polydisperse size distribution synthesized by thermal catalytic pyrolysis of silane form small open clusters. The Sauter mean diameters of the primary particles of the two types of nanoparticles were obtained from USAXS particle volume to surface ratio, with values of ∼41 and ∼21 nm obtained for the high energy milled and pyrolysis samples, respectively. Assuming a log-normal distribution of the particles, the geometric standard deviation of the particles was calculated to be ∼1.48 for all the samples, using parameters derived from the unified fit to the USAXS data. The flow properties of the inks and substrate combination lead to quantitative changes in the mean particle separation, with slowly curing systems with good capillary flow resulting in denser networks with smaller aggregates and better contact between particles.

Preparing Monodisperse Macromolecular Samples for Successful Biological Small-Angle X-ray and Neutron Scattering Experiments

Science.gov (United States)

Jeffries, Cy M.; Graewert, Melissa A.; Blanchet, Clément E.; Langley, David B.; Whitten, Andrew E.; Svergun, Dmitri I

2017-01-01

Small-angle X-ray and neutron scattering (SAXS and SANS) are techniques used to extract structural parameters and determine the overall structures and shapes of biological macromolecules, complexes and assemblies in solution. The scattering intensities measured from a sample contain contributions from all atoms within the illuminated sample volume including the solvent and buffer components as well as the macromolecules of interest. In order to obtain structural information, it is essential to prepare an exactly matched solvent blank so that background scattering contributions can be accurately subtracted from the sample scattering to obtain the net scattering from the macromolecules in the sample. In addition, sample heterogeneity caused by contaminants, aggregates, mismatched solvents, radiation damage or other factors can severely influence and complicate data analysis so it is essential that the samples are pure and monodisperse for the duration of the experiment. This Protocol outlines the basic physics of SAXS and SANS and reveals how the underlying conceptual principles of the techniques ultimately ‘translate’ into practical laboratory guidance for the production of samples of sufficiently high quality for scattering experiments. The procedure describes how to prepare and characterize protein and nucleic acid samples for both SAXS and SANS using gel electrophoresis, size exclusion chromatography and light scattering. Also included are procedures specific to X-rays (in-line size exclusion chromatography SAXS) and neutrons, specifically preparing samples for contrast matching/variation experiments and deuterium labeling of proteins. PMID:27711050

DMSO-induced dehydration of DPPC membranes studied by x-ray diffraction, small angle neutron scattering and calorimetry

International Nuclear Information System (INIS)

Kiselev, M.A.; Kiselev, A.M.; Lesieur, P.; Grabielle-Madelmond, C.; Ollivon, M.

1998-01-01

The properties of dimethyl sulfoxide (DMSO), a cryoprotector well known for its biological and therapeutic applications, were investigated on lipid membranes by x-ray diffraction, differential scanning calorimetry (DSC) and small angle neutron scattering (SANS). The DSC study of water freezing and melting of ice was performed in the ternary system which consists of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC)/DMSO/water system. The influence of DMSO on the DPPC membrane structure was established in the excess of solvent in the region of DMSO mole fraction from 0.0 to 1.0. The methods applied demonstrated the differences in the membrane structure in three sub-regions of DMSO mole fraction (X DMSO ) from 0.0 to 0.3 for the first, from 0.3 to 0.9 for the second, and from 0.9 to 1.0 for the third sub-region. The results for 0.0 ≤ X DMSO ≤ 0.3 can be explained in the framework of DMSO-induced dehydration of intermembrane space

X-ray fluorescence analysis of thin films at glancing-incident and -takeoff angles

International Nuclear Information System (INIS)

Tsuji, K.; Sato, S.; Hirokawa, K.

1995-01-01

We have developed a new analytical method, Glancing-Incidence and -Takeoff X-Ray Fluorescence (GIT-XRF) method for the first time. Here, we present an idea for a thin-film analysis and a surface analysis by the GIT-XRF method. In this method, the dependence of the fluorescent x-ray intensity on takeoff angle is measured at various incident angles of the primary x-ray. Compared with a total reflection x-ray fluorescence method, the GIT-XRF method allows a detailed thin-film analysis, because the thin film is cross-checked by many experimental curves. Moreover, a surface-sensitive analysis is also possible by the GIT-XRF method. (author)

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.

The small angle x-ray scattering of globular proteins in solution during heat denaturation

Science.gov (United States)

Banuelos, Jose; Urquidi, Jacob

2008-10-01

The ability of proteins to change their conformation in response to changes in their environment has consequences in biological processes like metabolism, chemical regulation in cells, and is believed to play a role in the onset of several neurodegenerative diseases. Factors such as a change in temperature, pressure, and the introduction of ions into the aqueous environment of a protein can give rise to the folding/unfolding of a protein. As a protein unfolds, the ratio of nonpolar to polar groups exposed to water changes, affecting a protein's thermodynamic properties. Using small angle x-ray scattering (SAXS), we are currently studying the intermediate protein conformations that arise during the folding/unfolding process as a function of temperature for five globular proteins. Trends in the observed intermediate structures of these globular proteins, along with correlations with data on protein thermodynamics may help elucidate shared characteristics between all proteins in the folding/unfolding process. Experimental design considerations will be discussed and preliminary results for some of these systems will be presented.

X-ray magnetic circular dichroism and small angle neutron scattering studies of thiol capped gold nanoparticles.

Energy Technology Data Exchange (ETDEWEB)

de la Venta, J.; Bouzas, V.; Pucci, A.; Laguna-Marco, M. A.; Haskel, D.; te Velthuis, S. G. E; Hoffmann, A.; Lal, J.; Bleuel, M.; Ruggeri, G.; de Julian Fernandez, C.; Garcia, M. A.; Univ.Complutense de Madrid; Inst. de Magnetismo Aplicado; Univ. of Pisa; Lab. di Magnetismo Molecolare

2009-01-01

X-ray magnetic circular dichroism (XMCD) and Small Angle Neutron Scattering (SANS) measurements were performed on thiol capped Au nanoparticles (NPs) embedded into polyethylene. An XMCD signal of 0.8 {center_dot} 10{sup -4} was found at the Au L{sub 3} edge of thiol capped Au NPs embedded in a polyethylene matrix for which Superconducting Quantum Interference Device (SQUID) magnetometry yielded a saturation magnetization, M{sub s}, of 0.06 emu/g{sub Au}. SANS measurements showed that the 3.2 nm average-diameter nanoparticles are 28% polydispersed, but no detectable SANS magnetic signal was found with the resolution and sensitivity accessible with the neutron experiment. A comparison with previous experiments carried out on Au NPs and multilayers, yield to different values between XMCD signals and magnetization measured by SQUID magnetometer. We discuss the origin of those differences.

X-ray magnetic circular dichroism and small angle neutron scattering study of thiol capped gold nanoparticles.

Energy Technology Data Exchange (ETDEWEB)

de la Venta, J.; Bouzas, V.; Pucci, A.; Laguna-Marco, M. A.; Haskel, D.; Pinel, E. F.; te Velthuis, S. G. E.; Hoffmann, A.; Lal, J.; Bleuel, M.; Ruggeri, G.; de Julian, C.; Garcia, M. A.; Univ. Complutense de Madrid; Inst. de Magnetismo Aplicado UCM; Univ. Pisa; Univ. di Padova

2009-11-01

X-ray magnetic circular dichroism (XMCD) and Small Angle Neutron Scattering (SANS) measurements were performed on thiol capped Au nanoparticles (NPs) embedded into polyethylene. An XMCD signal of 0.8 {center_dot} 10{sup -4} was found at the Au L{sub 3} edge of thiol capped Au NPs embedded in a polyethylene matrix for which Superconducting Quantum Interference Device (SQUID) magnetometry yielded a saturation magnetization, M{sub s}, of 0.06 emu/g{sub Au}. SANS measurements showed that the 3.2 nm average-diameter nanoparticles are 28% polydispersed, but no detectable SANS magnetic signal was found with the resolution and sensitivity accessible with the neutron experiment. A comparison with previous experiments carried out on Au NPs and multilayers, yield to different values between XMCD signals and magnetization measured by SQUID magnetometer. We discuss the origin of those differences.

The applications of small-angle X-ray scattering in studying nano-scaled polyoxometalate clusters in solutions

Science.gov (United States)

Li, Mu; Zhang, Mingxin; Wang, Weiyu; Cheng, Stephen Z. D.; Yin, Panchao

2018-05-01

Nano-scaled polyoxometalates (POMs) clusters with sizes ranging from 1 to 10 nm attract tremendous attention and have been extensively studied due to POMs' fascinating structural characteristics and prospects for wide-ranging applications. As a unique class of nanoparticles with well-defined structural topologies and monodispersed masses, the structures and properties of POMs in both bulk state and solutions have been explored with several well-developed protocols. Small-angle X-ray scattering (SAXS) technique, as a powerful tool for studying polymers and nanoparticles, has been recently extended to the investigating of solution behaviors of POMs. In this mini-review, the general principle and typical experimental procedures of SAXS are illustrated first. The applications of SAXS in characterizing POMs' morphology, counterion distribution around POMs, and short-range interactions among POMs in solutions are highlighted. [Figure not available: see fulltext.

Recent developments and ASAXS measurements at the ultra small angle X-ray scattering instrument of HASYLAB

CERN Document Server

Krosigk, G V; Gehrke, R; Kranold, R

2001-01-01

The wiggler beamline BW4 at the synchrotron radiation facility HASYLAB (DESY) is mainly designed for Ultra Small Angle X-ray Scattering (USAXS) and usually operated with detector-sample distances up to 13 m and at photon energies between 4 and 16 keV. With a new optical design the largest observable correlation distances have now been increased up to 9x10 sup 3 A. A grazing incidence set-up [P. Mueller-Buschbaum et al., Europhys. Lett. 42 (5) (1998) 517], vapor chamber, furnace, tensile testing machine and other instruments make the USAXS beamline attractive for a variety of scattering experiments [A. Endres et al., Rev. Sci. Instrum. 11 (1997) 68; A. Karl et al., J. Macromolecular Sci.-Phys. B 38 (5 and 6) (1999) 901; S. Minko et al., J. Macromolecular Sci., Phys. B 38 (5 and 6) (1999) 913]. A fully evacuated beampath allows high quality measurements with very low background signal. A photodiode mounted in the primary beam stop registers the primary beam flux simultaneously to the data acquisition and thus p...

Limited-angle x-ray luminescence tomography: methodology and feasibility study

International Nuclear Information System (INIS)

Carpenter, C M; Pratx, G; Sun, C; Xing, L

2011-01-01

X-ray luminescence tomography (XLT) has recently been proposed as a new imaging modality for biological imaging applications. This modality utilizes phosphor nanoparticles which luminesce near-infrared light when excited by x-ray photons. The advantages of this modality are that it uniquely combines the high sensitivity of radioluminescent nanoparticles and the high spatial localization of collimated x-ray beams. Currently, XLT has been demonstrated using x-ray spatial encoding to resolve the imaging volume. However, there are applications where the x-ray excitation may be limited by geometry, where increased temporal resolution is desired, or where a lower dose is mandatory. This paper extends the utility of XLT to meet these requirements by incorporating a photon propagation model into the reconstruction algorithm in an x-ray limited-angle (LA) geometry. This enables such applications as image-guided surgery, where the ability to resolve lesions at depths of several centimeters can be the key to successful resection. The hybrid x-ray/diffuse optical model is first formulated and then demonstrated in a breast-sized phantom, simulating a breast lumpectomy geometry. Both numerical and experimental phantoms are tested, with lesion-simulating objects of various sizes and depths. Results show localization accuracy with median error of 2.2 mm, or 4% of object depth, for small 2-14 mm diameter lesions positioned from 1 to 4.5 cm in depth. This compares favorably with fluorescence optical imaging, which is not able to resolve such small objects at this depth. The recovered lesion size has lower size bias in the x-ray excitation direction than the optical direction, which is expected due to the increased optical scatter. However, the technique is shown to be quite invariant in recovered size with respect to depth, as the standard deviation is less than 2.5 mm. Sensitivity is a function of dose; radiological doses are found to provide sufficient recovery for μg ml -1

Modern X-ray difraction. X-ray diffractometry for material scientists, physicists, and chemicists

International Nuclear Information System (INIS)

Spiess, L.; Schwarzer, R.; Behnken, H.; Teichert, G.

2005-01-01

The book yields a comprehensive survey over the applications of X-ray diffraction in fields like material techniques, metallurgy, electrotechniques, machine engineering, as well as micro- and nanotechniques. The necessary fundamental knowledge on X-ray diffraction are mediated foundedly and illustratively. Thereby new techniques and evaluation procedures are presented as well as well known methods. The content: Production and properties of X radiation, diffraction of X radiation, hardware for X-ray diffraction, methods of X-ray diffraction, lattice-constant determination, phase analysis, X-ray profile analysis, crystal structure analysis, X-ray radiographic stress analysis, X-ray radiographic texture analysis, crystal orientation determination, pecularities at thin films, small angle scattering

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

Science.gov (United States)

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

Conformational Flexibility of Proteins Involved in Ribosome Biogenesis: Investigations via Small Angle X-ray Scattering (SAXS

Directory of Open Access Journals (Sweden)

Dritan Siliqi

2018-02-01

Full Text Available The dynamism of proteins is central to their function, and several proteins have been described as flexible, as consisting of multiple domains joined by flexible linkers, and even as intrinsically disordered. Several techniques exist to study protein structures, but small angle X-ray scattering (SAXS has proven to be particularly powerful for the quantitative analysis of such flexible systems. In the present report, we have used SAXS in combination with X-ray crystallography to highlight their usefulness at characterizing flexible proteins, using as examples two proteins involved in different steps of ribosome biogenesis. The yeast BRCA2 and CDKN1A-interactig protein, Bcp1, is a chaperone for Rpl23 of unknown structure. We showed that it consists of a rigid, slightly elongated protein, with a secondary structure comprising a mixture of alpha helices and beta sheets. As an example of a flexible molecule, we studied the SBDS (Shwachman-Bodian-Diamond Syndrome protein that is involved in the cytoplasmic maturation of the 60S subunit and constitutes the mutated target in the Shwachman-Diamond Syndrome. In solution, this protein coexists in an ensemble of three main conformations, with the N- and C-terminal ends adopting different orientations with respect to the central domain. The structure observed in the protein crystal corresponds to an average of those predicted by the SAXS flexibility analysis.

Quantitative analysis of inclusions in low carbon free cutting steel using small-angle X-ray and neutron scattering

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)

Outburst of the 2 s Anomalous X-ray Pulsar 1E 1547.0-5408

Science.gov (United States)

Halpern, J. P.; Gotthelf, E. V.; Camilo, F.; Reynolds, J.; Ransom, S. M.

2008-01-01

Following our discovery of radio pulsations from the newly recognized anomalous X-ray pulsar (AXP) 1E 1547.0-5408, we initiated X-ray monitoring with the Swift X-ray telescope and obtained a single target-of-opportunity observation with the Newton X-ray Multi-Mirror Mission (XMM-Newton). In comparison with its historic minimum flux of 3 x 10(exp -l3)ergs/sq cm/s, the source was found to be in a record high state, f(sub x)(1-8 keV) = 5 x 10(exp -12)ergs/sq cm/s, or L(sub x) = 1.7 x 10(exp 35)(d/9 kpc )(sup 2)ergs/s, and declining by 25% in 1 month. Extrapolating the decay, we bound the total energy in this outburst to 1042 ergs pulsar, which may indicate a nearly aligned rotator. As also inferred from the transient behavior of XTE J18 10-197, the only other AXP known to emit in the radio, the magnetic field rearrangement responsible for this X-ray outburst of 1E 1547.0-5408 is probably the cause of its radio turn-on.

Assessment of firing conditions in old fired-clay bricks. The contribution of X-ray powder diffraction with the Rietveld method and small angle neutron scattering

Czech Academy of Sciences Publication Activity Database

Viani, Alberto; Sotiriadis, Konstantinos; Len, A.; Šašek, Petr; Ševčík, Radek

2016-01-01

Roč. 116, June (2016), s. 33-43 ISSN 1044-5803 R&D Projects: GA MŠk(CZ) LO1219 Keywords : fired- clay brick * Rietveld method * small angle neutron scattering * X-ray diffraction * firing temperature Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.714, year: 2016 http://www.sciencedirect.com/science/article/pii/S1044580316300870

Purification, crystallization, small-angle X-ray scattering and preliminary X-ray diffraction analysis of the SH2 domain of the Csk-homologous kinase.

Science.gov (United States)

Gunn, Natalie J; Gorman, Michael A; Dobson, Renwick C J; Parker, Michael W; Mulhern, Terrence D

2011-03-01

The C-terminal Src kinase (Csk) and Csk-homologous kinase (CHK) are endogenous inhibitors of the proto-oncogenic Src family of protein tyrosine kinases (SFKs). Phosphotyrosyl peptide binding to their Src-homology 2 (SH2) domains activates Csk and CHK, enhancing their ability to suppress SFK signalling; however, the detailed mechanistic basis of this activation event is unclear. The CHK SH2 was expressed in Escherichia coli and the purified protein was characterized as monomeric by synchrotron small-angle X-ray scattering in-line with size-exclusion chromatography. The CHK SH2 crystallized in 0.2 M sodium bromide, 0.1 M bis-Tris propane pH 6.5 and 20% polyethylene glycol 3350 and the best crystals diffracted to ∼1.6 Å resolution. The crystals belonged to space group P2, with unit-cell parameters a=25.8, b=34.6, c=63.2 Å, β=99.4°.

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.)

Structural evaluation of an amyloid fibril model using small-angle x-ray scattering

Science.gov (United States)

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.

Structural characterization of the phospholipid stabilizer layer at the solid-liquid interface of dispersed triglyceride nanocrystals with small-angle x-ray and neutron scattering

Science.gov (United States)

Schmiele, Martin; Schindler, Torben; Unruh, Tobias; Busch, Sebastian; Morhenn, Humphrey; Westermann, Martin; Steiniger, Frank; Radulescu, Aurel; Lindner, Peter; Schweins, Ralf; Boesecke, Peter

2013-06-01

Dispersions of crystalline nanoparticles with at least one sufficiently large unit cell dimension can give rise to Bragg reflections in the small-angle scattering range. If the nanocrystals possess only a small number of unit cells along these particular crystallographic directions, the corresponding Bragg reflections will be broadened. In a previous study of phospholipid stabilized dispersions of β-tripalmitin platelets [Unruh, J. Appl. Crystallogr.JACGAR0021-889810.1107/S0021889807044378 40, 1008 (2007)], the x-ray powder pattern simulation analysis (XPPSA) was developed. The XPPSA method facilitates the interpretation of the rather complicated small-angle x-ray scattering (SAXS) curves of such dispersions of nanocrystals. The XPPSA method yields the distribution function of the platelet thicknesses and facilitates a structural characterization of the phospholipid stabilizer layer at the solid-liquid interface between the nanocrystals and the dispersion medium from the shape of the broadened 001 Bragg reflection. In this contribution an improved and extended version of the XPPSA method is presented. The SAXS and small-angle neutron scattering patterns of dilute phospholipid stabilized tripalmitin dispersions can be reproduced on the basis of a consistent simulation model for the particles and their phospholipid stabilizer layer on an absolute scale. The results indicate a surprisingly flat arrangement of the phospholipid molecules in the stabilizer layer with a total thickness of only 12 Å. The stabilizer layer can be modeled by an inner shell for the fatty acid chains and an outer shell including the head groups and additional water. The experiments support a dense packing of the phospholipid molecules on the nanocrystal surfaces rather than isolated phospholipid domains.

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.)

DMSO-induced dehydration of DPPC membranes studied by x-ray diffraction, small angle neutron scattering and calorimetry

Energy Technology Data Exchange (ETDEWEB)

Kiselev, M A; Kiselev, A M [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Lesieur, P [LURE, Universite Paris-Sud, Bat. 209-D, F91405 Orsay cedex, (France); Grabielle-Madelmond, C; Ollivon, M [Physico-Chimie des systemes polyphases, URA 1218 du CNRS, Faculte de Pharmacie, tour B, F-92296, Chatenay Malabry (France)

1998-12-01

The properties of dimethyl sulfoxide (DMSO), a cryoprotector well known for its biological and therapeutic applications, were investigated on lipid membranes by x-ray diffraction, differential scanning calorimetry (DSC) and small angle neutron scattering (SANS). The DSC study of water freezing and melting of ice was performed in the ternary system which consists of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC)/DMSO/water system. The influence of DMSO on the DPPC membrane structure was established in the excess of solvent in the region of DMSO mole fraction from 0.0 to 1.0. The methods applied demonstrated the differences in the membrane structure in three sub-regions of DMSO mole fraction (X{sub DMSO}) from 0.0 to 0.3 for the first, from 0.3 to 0.9 for the second, and from 0.9 to 1.0 for the third sub-region. The results for 0.0 {<=} X{sub DMSO} {<=} 0.3 can be explained in the framework of DMSO-induced dehydration of intermembrane space 11 refs., 7 figs. Submitted to the Conference `ISSRNS`98`, 15-20 Jun 1998, Ustron-Jaszowiec, Poland

The development for small scale soft X-ray spectrometer

International Nuclear Information System (INIS)

Sun Kexu; Jiang Shaoen; Yi Rongqing; Cui Yanli

2004-12-01

For the development of small-scale soft X-ray spectrometer, first, some small-scale soft X-ray detection elements are developed, it is included GaAs irradiated with neutron, GaAs irradiated with proton, multi-layer mirror, plane mirror and small scale X-ray diode et al. Soft X-ray spectrometers built of multi-layer mirror-GaAs (with neutron irradiation), and plane mirror-small-scale XRD, and plane mirror-GaAs (with proton irradiation) are prepared. These spectrometers are examined in Shen Guang-II laser facility, and some external estimation are given. (authors)

Anomalous X-ray scattering studies of short-, intermediate- and extended-range order in glasses

International Nuclear Information System (INIS)

Price, D.L.; Saboungi, M.L.; Armand, P.; Cox, D.E.

1998-01-01

The authors present the formalism of anomalous x-ray scattering as applied to partial structure analysis of disordered materials, and give an example of how the technique has been applied, together with that of neutron diffraction, to investigate short-, intermediate- and extended-range order in vitreous germania and rubidium germanate

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.

A Grazing-Incidence Small-Angle X-Ray Scattering View of Vertically Aligned ZnO Nano wires

International Nuclear Information System (INIS)

Lavcevic, M.L.; Silovic, L.; Dubcek, P.; Pavlovic, M.; Bernstorff, S.

2013-01-01

We report a grazing-incidence small-angle X-ray scattering study of ZnO films with vertically aligned and randomly distributed nano wires, grown through a hydrothermal growth process on nano structured ZnO seeding coatings and deposited by electron beam evaporation on silicon and glass, respectively. The comparison of the scattering patterns of seeding coatings and nano wires showed that the scattering of vertically aligned nano wires exhibited a specific feature: the dominant characteristic of their scattering patterns is the appearance of fine structure effects around the specular peak. These effects were clarified by the combined reflection and scattering phenomena, suggested for the aligned nano wires-substrate system. Furthermore, they enabled the calculation of the average gyration radius of nano wires in horizontal direction. The calculated value was in good agreement with the radii of nano wires estimated by surface electron microscopy. Therefore, the observed feature in the scattering pattern can serve as evidence of the aligned growth of nano wires.

Automation and remote access of EMBL small angle X-ray scattering beamline X33 dedicated to biological macromolecules

International Nuclear Information System (INIS)

Weifeng Shang; Roessle, M.; Blanchet, C.; Zozulya, A.; Franke, D.; Petoukhov, M.; Kikhney, A.; Svergun, D.

2009-01-01

Full text: The small-angle X-ray scattering beamline X33 of the European Molecular Biology Laboratory (EMBL) at the DORIS III storage ring (HASYLAB/DESY) has been dedicated to structural studies of non-crystalline biological systems for more than two decades. In the last several years, the introduction of new optical systems (monochromator, mirror, slits etc) and detector systems (large area image plate Mar345 and PILATUS 1M) leads to an improvement of photon flux by a factor of 3 and a reduction of the exposure time by a factor of 7. Moreover, an automated sample changer has been constructed and in operation since August 2007. The data analysis pipeline consisting of the program suite yields the radius of gyration and forward scattering intensity using Guinier analysis (AutoRg), pair distance distribution function p(r) using indirect Fourier transform method (AutoGNOM), and bead models using ab initio shape determination (DAMMIN and DAMMIF). The results of these analysis which are immediately available after each measurement provides an invaluable tool for data quality control during the data collection. Furthermore, works on remote control of the integrated data collection and analysis software is ongoing and expected to be operated in late 2009 where users can send their samples and control the measurements at home institutes. (author)

Micellar Surfactant Association in the Presence of a Glucoside-based Amphiphile Detected via High-Throughput Small Angle X-ray Scattering

Energy Technology Data Exchange (ETDEWEB)

Stanic, Vesna [Brazilian Synchrotron Light Source, Campinas (Brazil); Broadbent, Charlotte [Columbia Univ., New York, NY (United States). Engineering Dept.; DiMasi, Elaine [Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences Division; Galleguillos, Ramiro [Lubrizol Advanced Materials, Cleveland, OH (United States); Woodward, Valerie [Lubrizol Advanced Materials, Cleveland, OH (United States)

2016-11-14

The interactions of mixtures of anionic and amphoteric surfactants with sugar amphiphiles were studied via high throughput small angle x-ray scattering (SAXS). The sugar amphiphile was composed of Caprate, Caprylate, and Oleate mixed ester of methyl glucoside, MeGCCO. Optimal surfactant interactions are sought which have desirable physical properties, which must be identified in a cost effective manner that can access the large phase space of possible molecular combinations. X-ray scattering patterns obtained via high throughput SAXS can probe a combinatorial sample space and reveal the incorporation of MeGCCO into the micelles and the molecular associations between surfactant molecules. Such data make it possible to efficiently assess the effects of the new amphiphiles in the formulation. A specific finding of this study is that formulations containing comparatively monodisperse and homogeneous surfactant mixtures can be reliably tuned by addition of NaCl, which swells the surfactant micelles with a monotonic dependence on salt concentration. In contrast, the presence of multiple different surfactants destroys clear correlations with NaCl concentration, even in otherwise similar series of formulations.

Experimental set-up for time resolved small angle X-ray scattering studies of nanoparticles formation using a free-jet micromixer

Energy Technology Data Exchange (ETDEWEB)

Marmiroli, Benedetta [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria); Grenci, Gianluca [TASC INFM/CNR, SS 14 km 163.5, Basovizza, TS (Italy); Cacho-Nerin, Fernando; Sartori, Barbara; Laggner, Peter [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria); Businaro, Luca [TASC INFM/CNR, SS 14 km 163.5, Basovizza, TS (Italy); Amenitsch, Heinz, E-mail: heinz.amenitsch@elettra.trieste.i [Institute for Biophysics and Nanosystem Research, Austrian Academy of Science, Schmiedlstrasse 6, Graz (Austria)

2010-02-15

Recently, we have designed, fabricated and tested a free-jet micromixer for time resolved small angle X-ray scattering (SAXS) studies of nanoparticles formation in the <100 mus time range. The microjet has a diameter of 25 mum and a time of first accessible measurement of 75 mus has been obtained. This result can still be improved. In this communication, we present a method to estimate whether a given chemical or biological reaction can be investigated with the micromixer, and to optimize the beam size for the measurement at the chosen SAXS beamline. Moreover, we describe a system based on stereoscopic imaging which allows the alignment of the jet with the X-ray beam with a precision of 20 mum. The proposed experimental procedures have been successfully employed to observe the formation of calcium carbonate (CaCO{sub 3}) nanoparticles from the reaction of sodium carbonate (Na{sub 2}CO{sub 3}) and calcium chloride (CaCl{sub 2}). The induction time has been estimated in the order of 200 mus and the determined radius of the particles is about 14 nm.

Small-angle x-ray scattering and density measurements of liquid Se50-Te50 mixture at high temperatures and high pressures using synchrotron radiation

International Nuclear Information System (INIS)

Kajihara, Y; Inui, M; Matsuda, K; Tomioka, Y

2010-01-01

We have carried out small-angle x-ray scattering and x-ray transmission measurements of liquid Se 50 -Te 50 mixture at SPring-8 in Japan and obtained the structure factor S(Q) at small-Q region (0.6 -1 ) and the density at high temperatures and high pressures up to 1000 0 C and 180 MPa. We report preliminary results in this paper. With increasing temperature, the density shows a minimum at around 500 0 C and a maximum at around 700 0 C. On the other hand, S(0) becomes maximum and S(Q) strongly depends on Q at around 600 0 C, which is about the middle temperature where the density shows the minimum and maximum. The temperatures shift to lower side when the pressure increases. These results prove that, with increasing temperature, the sample exhibits gradual transition from low-density structure to high-density structure, which causes mesoscopic density fluctuations in the intermediate temperature region.

Simbol-X Mirror Module Thermal Shields: II-Small Angle X-Ray Scattering Measurements

Science.gov (United States)

Barbera, M.; Ayers, T.; Collura, A.; Nasillo, G.; Pareschi, G.; Tagliaferri, G.

2009-05-01

The formation flight configuration of the Simbol-X mission implies that the X-ray mirror module will be open to Space on both ends. In order to reduce the power required to maintain the thermal stability and, therefore, the high angular resolution of the shell optics, a thin foil thermal shield will cover the mirror module. Different options are presently being studied for the foil material of these shields. We report results of an experimental investigation conducted to verify that the scattering of X-rays, by interaction with the thin foil material of the thermal shield, will not significantly affect the performances of the telescope.

Simbol-X Mirror Module Thermal Shields: II-Small Angle X-Ray Scattering Measurements

International Nuclear Information System (INIS)

Barbera, M.; Ayers, T.; Collura, A.; Nasillo, G.; Pareschi, G.; Tagliaferri, G.

2009-01-01

The formation flight configuration of the Simbol-X mission implies that the X-ray mirror module will be open to Space on both ends. In order to reduce the power required to maintain the thermal stability and, therefore, the high angular resolution of the shell optics, a thin foil thermal shield will cover the mirror module. Different options are presently being studied for the foil material of these shields. We report results of an experimental investigation conducted to verify that the scattering of X-rays, by interaction with the thin foil material of the thermal shield, will not significantly affect the performances of the telescope.

Use of dynamic light scattering and small-angle X-ray scattering to characterize new surfactants in solution conditions for membrane-protein crystallization

Science.gov (United States)

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

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

Refraction angle and edge visibility in X-ray diffraction enhanced imaging

International Nuclear Information System (INIS)

Chen Yu; Jia Quanjie; Li Gang; Wang Yuzhu; Xue Xianying; Jiang Xiaoming

2007-01-01

Diffraction-enhanced X-ray imaging could extract accurately the refraction angles of the sample, which is very important to increase the image contrast of low Z samples. In this paper, the DEI experiments with X-rays of different energies were performed both on wedge-shaped and rounded model samples. Refraction angles of the two samples were all obtained accurately, and the results agreed well with the calculations. Quantitative analyses based on Edge Visibility were performed for the wedge-shaped model sample. The results revealed that the calculated positions for the Best Edge Visibility of the slope with fixed refraction angle were calculable in good agreement with the experimental results. A quantitative research on the Edge Visibility of real tissues sample was carried out and the optimal condition for best contrast of DEI images were discussed. (authors)

X-ray optics and X-ray microscopes: new challenges

International Nuclear Information System (INIS)

Susini, J.

2004-01-01

Soon after the discovery of X-rays in 1895 by W. Roentgen, it became rapidly clear that the methods traditionally used in the visible light regime, namely refraction, diffraction and reflection were difficult to apply for X-ray optics. The physical origins of these difficulties are closely linked to the very nature of interaction of X-rays with matter. The small deviation δ of the refractive index of condensed matter from unity makes it difficult to extend refraction-based optics from the optical spectral region to the X-ray region because the refraction angle is proportional to δ. Similarly it is very challenging to extend diffraction-based focusing techniques to X-rays because the diffraction angle scales inversely with wavelength. Finally, the use of reflection-based optics is also limited by the very small critical angle for total reflection. All those fundamental limitations prevented for almost one century, the development of X-ray microscopy whereas electron microscopy became a standard tool. In the past twenty years, interests for X-ray microscopy revived, mainly because of several major advances in X-ray sources and X-ray optics. X-ray microscopy techniques are now emerging as powerful and complementary tools for submicron investigations. Soft X-ray microscopes offer traditionally the possibility to form direct images of thick hydrated biological material in near-native environment, at a spatial resolution well beyond that achievable with visible light microscopy. Natural contrast is available in the soft X-ray region, in the so-called ''water-window'', due to the presence of absorption edges of the major constituents (C,N,O). Recent advances in manufacturing techniques have enlarged the accessible energy range of micro-focussing optics and offer new applications in a broad range of disciplines. X-ray microscopy in the 1 - 30 keV energy range is better suited for fluorescence to map trace elements, tomography for 3D imaging and micro-diffraction. The

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 X-Ray analysis of macromolecular structure: the structure of protein NS2 (NEP) in solution

Science.gov (United States)

Shtykova, E. V.; Bogacheva, E. N.; Dadinova, L. A.; Jeffries, C. M.; Fedorova, N. V.; Golovko, A. O.; Baratova, L. A.; Batishchev, O. V.

2017-11-01

A complex structural analysis of nuclear export protein NS2 (NEP) of influenza virus A has been performed using bioinformatics predictive methods and small-angle X-ray scattering data. The behavior of NEP molecules in a solution (their aggregation, oligomerization, and dissociation, depending on the buffer composition) has been investigated. It was shown that stable associates are formed even in a conventional aqueous salt solution at physiological pH value. For the first time we have managed to get NEP dimers in solution, to analyze their structure, and to compare the models obtained using the method of the molecular tectonics with the spatial protein structure predicted by us using the bioinformatics methods. The results of the study provide a new insight into the structural features of nuclear export protein NS2 (NEP) of the influenza virus A, which is very important for viral infection development.

Anomalous X-ray scattering studies on semiconducting and metallic glasses

International Nuclear Information System (INIS)

Hosokawa, S.; Pilgrim, W.C.; Berar, J.F.; Kohara, S.

2012-01-01

In order to explore local- and intermediate-range atomic structures of several semiconducting and metallic glasses, anomalous X-ray scattering (AXS) experiments were performed using an improved detecting system suitable for third-generation synchrotron radiation facilities, and the obtained data were analyzed using reverse Monte Carlo (RMC) modelling to obtain partial structure factors and to construct three-dimensional atomic configurations of these glasses. Examples of GeSe 2 semiconducting and Pd 40 Ni 40 P 20 metallic glasses are demonstrated to exhibit the feasibility of the combination of AXS and RMC techniques. Importance of an additional combination with neutron scattering is also described for alloys containing light elements. (authors)

Dynamic angle selection in X-ray computed tomography

Energy Technology Data Exchange (ETDEWEB)

Dabravolski, Andrei, E-mail: andrei.dabravolski@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Batenburg, Kees Joost, E-mail: joost.batenburg@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Centrum Wiskunde and Informatica (CWI), Science Park 123, 1098 XG Amsterdam (Netherlands); Sijbers, Jan, E-mail: jan.sijbers@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium)

2014-04-01

Highlights: • We propose the dynamic angle selection algorithm for CT scanning. • The approach is based on the concept of information gain over a set of solutions. • Projection angles are selected based on the already available projection data. • The approach can lead to more accurate results from fewer projections. - Abstract: In X-ray tomography, a number of radiographs (projections) are recorded from which a tomogram is then reconstructed. Conventionally, these projections are acquired equiangularly, resulting in an unbiased sampling of the Radon space. However, especially in case when only a limited number of projections can be acquired, the selection of the angles has a large impact on the quality of the reconstructed image. In this paper, a dynamic algorithm is proposed, in which new projection angles are selected by maximizing the information gain about the object, given the set of possible new angles. Experiments show that this approach can select projection angles for which the accuracy of the reconstructed image is significantly higher compared to the standard angle selections schemes.

Dynamic angle selection in X-ray computed tomography

International Nuclear Information System (INIS)

Dabravolski, Andrei; Batenburg, Kees Joost; Sijbers, Jan

2014-01-01

Highlights: • We propose the dynamic angle selection algorithm for CT scanning. • The approach is based on the concept of information gain over a set of solutions. • Projection angles are selected based on the already available projection data. • The approach can lead to more accurate results from fewer projections. - Abstract: In X-ray tomography, a number of radiographs (projections) are recorded from which a tomogram is then reconstructed. Conventionally, these projections are acquired equiangularly, resulting in an unbiased sampling of the Radon space. However, especially in case when only a limited number of projections can be acquired, the selection of the angles has a large impact on the quality of the reconstructed image. In this paper, a dynamic algorithm is proposed, in which new projection angles are selected by maximizing the information gain about the object, given the set of possible new angles. Experiments show that this approach can select projection angles for which the accuracy of the reconstructed image is significantly higher compared to the standard angle selections schemes

Small-angle X-ray scattering studies on the X-ray induced aggregation of ribonnuclease, lactate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase and serum albumin. A comparison with malate synthase

International Nuclear Information System (INIS)

Zipper, P.; Gatterer, H.G.; Schutz, J.; Durchschlag, H.

1980-01-01

The X-ray induced aggregation of ribonuclease, lactate dehydrogenase (LDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and serum albumin in aqueous solution was monitored in situ by means of small-angle X-ray scattering. Measurements carried out with ribonuclease, LDH and serum albumin in the absence of dithiothreitol (DTT) and with GAPDH in the presence of 0.2mM DTT established the following series for the rates of aggregation of the proteins under these conditions: ribonuclease >LDH> >GAPDH> serum albumin. Within six hours from the beginning of irradiation (i.e. about the time required for the exposure of one complete scattering curve under the conditions of our experiments) the following increases of R tilde resulted: ribonuclease 9%, LDH 7%, GAPDH 4%, serum albumin <1%. Changes of R tilde exceeding 1% are, of course, too high to be tolerated in conventional scattering experiments. Measurements carried out with LDH and GAPDH in the presence of 2mM DTT established a strong protective effect of DTT against the X-ray induced aggregation of these enzymes. The initial increase of R tilde upon irradiation of LDH and GAPDH in the presence of 2mM DTT was found to be even lower than the increase of R tilde observed when serum albumin was irradiated in the absence of DTT. However, the observed decrease of anti x of LDH and GAPDH at the early stages of irradiation suggested the occurrence of fragmentation of the enzymes as another consequence of radiation damage. This finding is discussed in context with the results from previous scattering experiments and electrophoretic studies on malate synthase. (author)

Small angle X-ray scattering by TiO2/ZrO2 mixed oxide particles and a Synroc precursor

International Nuclear Information System (INIS)

Gazeau, D.; Zemb, T.; Amal, R.; Bartlett, J.

1992-09-01

This high resolution small angle X-ray scattering study of a concentrated oxide sol, precursor of the SYNROC matrix for the storage of the high level radioactive waste, evidences a locally cylindrical microstructure. Locally, nanometric cylinders show disordered axis with some concentration dependent connections. This microstructure explains the paradoxal stability of this oxide dispersions upon the addition of concentrated acidic solutions. This stability has a steric origin and electrostatic repulsions are not needed. The addition of aluminium to the initial titanium-zirconium mixture enhances branching on the locally cylindrical microstructure. Finally, we show that the solid powder obtained after calcination (drying) of the sol has the same specific area (∼ 1000 m 2 /g) than the sol. (Author). 23 refs., 7 figs., 1 tab

Azimuthal and polar angle dependence of L X-ray differential cross-sections of Yb at 59.54 keV photon energy

Energy Technology Data Exchange (ETDEWEB)

Akkuş, T.; Şahin, Y.; Yılmaz, D., E-mail: ddemir@atauni.edu.tr

2016-01-01

Highlights: • The azimuthal and polar angle dependence of L X-ray for Yb is investigated. • The azimuthal angle dependence of Ll and Lα X-rays are observed. • The azimuthal anisotropy of Lβ and Lγ X-rays are not observed. • The polar anisotropy of Ll and Lα X-rays are observed. • The polar anisotropy of Lβ and Lγ X-rays are not observed. - Abstract: The azimuthal and polar angle dependence of L X-ray was investigated in the same experimental setup to remove the existing ambiguity about alignments measurements. We measured Ll, Lα, Lβ and Lγ X-ray differential cross sections of Yb for several different azimuthal angles (30°, 20°, 10°, 0°, −10° and −20°) and polar angles (90°, 100°, 110°, 120°, 130° and 140°) at 59.54 keV photon energy by using a Si(Li) detector. The azimuthal angle dependence of Ll and Lα X-rays were observed. The azimuthal anisotropy of Lβ and Lγ X-rays were not observed. On the other hand, differential cross-sections for Lβ and Lγ X-rays were found independent on the polar angle within experimental error, those for Ll and Lα X-rays depended on the polar angles. Azimuthal and polar angles dependence of L X-ray differential cross-sections contrast with the other experimental and theoretical results, which report evidence of the isotropic emission of Ll and Lα X-rays following photoionization.

Evaluation of stress gradient by x-ray stress measurement based on change in angle phi

International Nuclear Information System (INIS)

Sasaki, Toshihiko; Kuramoto, Makoto; Yoshioka, Yasuo.

1985-01-01

A new principle of X-ray stress evaluation for a sample with steep stress gradient has been prosed. The feature of this method is that the stress is determined by using so-called phi-method based on the change of phi-angle and thus has no effect on the penetration depth of X-rays. The procedure is as follows; firstly, an average stress within the penetration depth of X-rays is determined by changing only phi-angle under a fixed psi-angle, and then a distribution of the average stress vs. the penetration depth of X-rays is detected by repeating the similar procedure at different psi-angles. The following conclusions were found out as the result of residual stress measurements on a carbon steel of type S 55 C polished by emery paper. This method is practical enough to use for a plane stress problem. And the assumption of a linear stress gradient adopted in the authors' previous investigations is valid. In case of a triaxial stress analysis, this method is effective for the solution of three shearing stresses. However, three normal stresses can not be solved perfectly except particular psi-angles. (author)

New developments in the simultaneous measurement system of wide-angle and small-angle x-ray scatterings and vibrational spectra for the static and dynamic analyses of the hierarchical structures of polymer solids

International Nuclear Information System (INIS)

Tashiro, Kohji; Yamamoto, Hiroko; Yoshioka, Taiyo; Ninh, Tran Hai; Shimada, Shigeru; Nakatani, Takeshi; Iwamoto, Hiroyuki; Ohta, Noboru; Masunaga, Hiroyasu

2012-01-01

A simultaneous measurement system of wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS) and Raman or transmission-type infrared spectroscopy was developed by us. Its purposes is to clarify the static and dynamic structural changes of polymer materials subjected to the various external condition changes. Some examples described here include the study of the stretch-induced reorientation phenomenon of a-axially-oriented polyethylene, the study of structural change in photo-induced solid-state polymerization reaction of muconic acid ester monomer crystal, the study of the two-stage high-temperature phase transitions of aliphatic nylons, the study of stress-induced crystalline phase transition of an oriented poly(tetramethylene terephthalate) sample and its relation to the higher-order structural change, and the study of structural regularization process of poly(L-lactic acid) in the isothermal crystallization of the meso phase. These case studies in the clarification of hierarchical structural changes of polymer materials have proven that the simultaneous measurement systems can be useful to examine the structural changes in polymer systems. (author)

Small Pixel Hybrid CMOS X-ray Detectors

Science.gov (United States)

Hull, Samuel; Bray, Evan; Burrows, David N.; Chattopadhyay, Tanmoy; Falcone, Abraham; Kern, Matthew; McQuaide, Maria; Wages, Mitchell

2018-01-01

Concepts for future space-based X-ray observatories call for a large effective area and high angular resolution instrument to enable precision X-ray astronomy at high redshift and low luminosity. Hybrid CMOS detectors are well suited for such high throughput instruments, and the Penn State X-ray detector lab, in collaboration with Teledyne Imaging Sensors, has recently developed new small pixel hybrid CMOS X-ray detectors. These prototype 128x128 pixel devices have 12.5 micron pixel pitch, 200 micron fully depleted depth, and include crosstalk eliminating CTIA amplifiers and in-pixel correlated double sampling (CDS) capability. We report on characteristics of these new detectors, including the best read noise ever measured for an X-ray hybrid CMOS detector, 5.67 e- (RMS).

Ultra-small-angle X-ray scattering characterization of diesel/gasoline soot: sizes and particle-packing conditions

Science.gov (United States)

Kameya, Yuki; Lee, Kyeong O.

2013-10-01

Regulations on particulate emissions from internal combustion engines tend to become more stringent, accordingly the importance of particulate filters in the after-treatment system has been increasing. In this work, the applicability of ultra-small-angle X-ray scattering (USAXS) to diesel soot cake and gasoline soot was investigated. Gasoline-direct-injection engine soot was collected at different fuel injection timings. The unified fits method was applied to analyze the resultant scattering curves. The validity of analysis was supported by comparing with carbon black and taking the sample images using a transmission electron microscope, which revealed that the primary particle size ranged from 20 to 55 nm. In addition, the effects of particle-packing conditions on the USAXS measurement were demonstrated by using samples suspended in acetone. Then, the investigation was extended to characterization of diesel soot cake deposited on a diesel particulate filter (DPF). Diesel soot was trapped on a small piece of DPF at different deposition conditions which were specified using the Peclet number. The dependence of scattering curve on soot-deposition conditions was demonstrated. To support the interpretation of the USAXS results, soot cake samples were observed using a scanning electron microscope and the influence of particle-packing conditions on scattering curve was discussed.

Ultra-small-angle X-ray scattering characterization of diesel/gasoline soot: sizes and particle-packing conditions

International Nuclear Information System (INIS)

Kameya, Yuki; Lee, Kyeong O.

2013-01-01

Regulations on particulate emissions from internal combustion engines tend to become more stringent, accordingly the importance of particulate filters in the after-treatment system has been increasing. In this work, the applicability of ultra-small-angle X-ray scattering (USAXS) to diesel soot cake and gasoline soot was investigated. Gasoline-direct-injection engine soot was collected at different fuel injection timings. The unified fits method was applied to analyze the resultant scattering curves. The validity of analysis was supported by comparing with carbon black and taking the sample images using a transmission electron microscope, which revealed that the primary particle size ranged from 20 to 55 nm. In addition, the effects of particle-packing conditions on the USAXS measurement were demonstrated by using samples suspended in acetone. Then, the investigation was extended to characterization of diesel soot cake deposited on a diesel particulate filter (DPF). Diesel soot was trapped on a small piece of DPF at different deposition conditions which were specified using the Peclet number. The dependence of scattering curve on soot-deposition conditions was demonstrated. To support the interpretation of the USAXS results, soot cake samples were observed using a scanning electron microscope and the influence of particle-packing conditions on scattering curve was discussed

Ultra-small-angle X-ray scattering characterization of diesel/gasoline soot: sizes and particle-packing conditions

Energy Technology Data Exchange (ETDEWEB)

Kameya, Yuki, E-mail: ykameya@anl.gov; Lee, Kyeong O. [Argonne National Laboratory, Center for Transportation Research (United States)

2013-10-15

Regulations on particulate emissions from internal combustion engines tend to become more stringent, accordingly the importance of particulate filters in the after-treatment system has been increasing. In this work, the applicability of ultra-small-angle X-ray scattering (USAXS) to diesel soot cake and gasoline soot was investigated. Gasoline-direct-injection engine soot was collected at different fuel injection timings. The unified fits method was applied to analyze the resultant scattering curves. The validity of analysis was supported by comparing with carbon black and taking the sample images using a transmission electron microscope, which revealed that the primary particle size ranged from 20 to 55 nm. In addition, the effects of particle-packing conditions on the USAXS measurement were demonstrated by using samples suspended in acetone. Then, the investigation was extended to characterization of diesel soot cake deposited on a diesel particulate filter (DPF). Diesel soot was trapped on a small piece of DPF at different deposition conditions which were specified using the Peclet number. The dependence of scattering curve on soot-deposition conditions was demonstrated. To support the interpretation of the USAXS results, soot cake samples were observed using a scanning electron microscope and the influence of particle-packing conditions on scattering curve was discussed.

Introducing a standard method for experimental determination of the solvent response in laser pump, x-ray probe time-resolved wide-angle x-ray scattering experiments on systems in solution

DEFF Research Database (Denmark)

Kjær, Kasper Skov; Brandt van Driel, Tim; Kehres, Jan

2013-01-01

In time-resolved laser pump, X-ray probe wide-angle X-ray scattering experiments on systems in solution the structural response of the system is accompanied by a solvent response. The solvent response is caused by reorganization of the bulk solvent following the laser pump event, and in order...... response-the solvent term-experimentally when applying laser pump, X-ray probe time-resolved wide-angle X-ray scattering. The solvent term describes difference scattering arising from the structural response of the solvent to changes in the hydrodynamic parameters: pressure, temperature and density. We...... is demonstrated to exhibit first order behaviour with respect to the amount of energy deposited in the solution. We introduce a standardized method for recording solvent responses in laser pump, X-ray probe time-resolved X-ray wide-angle scattering experiments by using dye mediated solvent heating. Furthermore...

Metal ion controlled self-assembly of a chemically reengineered protein drug studied by small-angle X-ray scattering

DEFF Research Database (Denmark)

Jesper, Nygaard; Munch, Henrik K.; Thulstrup, Peter W.

2012-01-01

. A small-angle X-ray scattering analysis of the bipyridine-modified insulin system confirmed an organization into a novel well-ordered structure based on insulin trimers, as induced by the addition of Fe(II). In contrast, unmodified monomeric insulin formed larger and more randomly structured assemblies......Precise control of the oligomeric state of proteins is of central importance for biological function and for the properties of biopharmaceutical drugs. Here, the self-assembly of 2,2′-bipyridine conjugated monomeric insulin analogues, induced through coordination to divalent metal ions, was studied....... This protein drug system was designed to form non-native homo-oligomers through selective coordination of two divalent metal ions, Fe(II) and Zn(II), respectively. The insulin type chosen for this study is a variant designed for a reduced tendency toward native dimer formation at physiological concentrations...

Structure of Nanoporous Biocarbon for Hydrogen Storage as Determined by Small Angle X-Ray Scattering

Science.gov (United States)

Wood, Mikael; Burress, J.; Pobst, J.; Carter, S.; Pfeifer, P.; Wexler, C.; Shah, P.; Suppes, G.

2008-03-01

As a member of the Alliance for Collaborative Research in Alternative Fuel Technology (ALL-CRAFT) our research group studies the properties of nanoporous biocarbon, produced from waste corn cob, with the goal of achieving the Department of Energy's gravimetric and volumetric standards for both hydrogen and methane gas storage. Small Angle X-Ray Scattering (SAXS) is a valuable tool in our investigation of the geometry of the pore space in our carbon samples. In this talk, we will compare the experimental SAXS data with theoretical results for various pore geometries to determine which pore models are consistent with experiment. Using data from nitrogen adsorption isotherms, along with SAXS, yields significant structural information about the pore space. This analysis should allow us to fully optimize our production process and to achieve the DOE's target storage capacities. This work supported by: 1. National Science Foundation (PFI-0438469) 2. U.S. Department of Education (P200A040038) 3. U.S. Department of Energy (DE-AC02-06CH11357) 4. University of Missouri (RB-06-040) 5. U.S. Department of Defense (N00164-07-P-1306) 6. U.S. Department of Energy (DE-FG02-07ER46411)

Selective molecular annealing: in situ small angle X-ray scattering study of microwave-assisted annealing of block copolymers.

Science.gov (United States)

Toolan, Daniel T W; Adlington, Kevin; Isakova, Anna; Kalamiotis, Alexis; Mokarian-Tabari, Parvaneh; Dimitrakis, Georgios; Dodds, Christopher; Arnold, Thomas; Terrill, Nick J; Bras, Wim; Hermida Merino, Daniel; Topham, Paul D; Irvine, Derek J; Howse, Jonathan R

2017-08-09

Microwave annealing has emerged as an alternative to traditional thermal annealing approaches for optimising block copolymer self-assembly. A novel sample environment enabling small angle X-ray scattering to be performed in situ during microwave annealing is demonstrated, which has enabled, for the first time, the direct study of the effects of microwave annealing upon the self-assembly behavior of a model, commercial triblock copolymer system [polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene]. Results show that the block copolymer is a poor microwave absorber, resulting in no change in the block copolymer morphology upon application of microwave energy. The block copolymer species may only indirectly interact with the microwave energy when a small molecule microwave-interactive species [diethylene glycol dibenzoate (DEGDB)] is incorporated directly into the polymer matrix. Then significant morphological development is observed at DEGDB loadings ≥6 wt%. Through spatial localisation of the microwave-interactive species, we demonstrate targeted annealing of specific regions of a multi-component system, opening routes for the development of "smart" manufacturing methodologies.

Anomalous x-ray scattering studies of functional disordered materials

International Nuclear Information System (INIS)

Kohara, S; Tajiri, H; Song, C H; Ohara, K; Temleitner, L; Sugimito, K; Fujiwara, A; Pusztai, L; Usuki, T; Hosokawa, S; Benino, Y; Kitamura, N; Fukumi, K

2014-01-01

We have developed anomalous x-ray scattering (AXS) spectrometers, that employ intrinsic Ge detectors and crystal analyzers, at SPring-8. The use of LiF analyzer crystal provides us with an energy resolution of ∼ 12 eV. Furthermore, it has been established that the use of AXS technique is essential to reveal the relationship between the atomic structure and its function of a fast phase-change material, Ge 2 Sb 2 Te 5 . We were able to address the issue of why the amorphous phase of fast phase change materials is stable at room temperature for a long time despite the fact that it can rapidly transform to the crystalline phase by using a combination of AXS and large scale density functional theory-based molecular dynamics simulations.

Characterization of structure and coagulation behaviour of refractory organic substances (ROS) using small-angle neutron scattering (SANS), small-angle x-ray scattering (SAXS) and x-ray microscopy; Charakterisierung von Struktur und Koagulationsverhalten von Refraktaeren Organischen Saeuren (ROS) mit Hilfe von Neutronenkleinwinkelstreuung (SANS), Roentgenkleinwinkelstreuung (SAXS) und Roentgenmikroskopie

Energy Technology Data Exchange (ETDEWEB)

Pranzas, P.K. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

1999-07-01

In this work structure, coagulation and complexation behaviour of aquatic refractory organic substances (ROS) (humic and fulvic acids) were characterized. For this purpose a structural analytical system with the methods small-angle neutron scattering (SANS), small-angle x-ray scattering (SAXS) and X-ray microscopy with synchrotron radiation was developed and established. Size distributions of ROS of different origin were calculated from the scattering curves. Spherical ROS units were obtained, which coagulated by forming chainlike structures or disordered ROS agglomerates at higher concentrations. Additionally the average molecular weights of several ROS were calculated. Studies of the coagulation behaviour of ROS towards copper ions resulted in larger ROS-agglomerates besides the spherical ROS units. A linear relation between the addition of Cu{sup 2+} and the formation of the ROS-Cu{sup 2+}-agglomerates was found. With X-ray microscopy an extensive ROS-Cu{sup 2}-network structure could be registrated. For mercury and cadmium ions such coagulation interactions were not found. Investigations with X-ray microscopy of the coagulation behaviour of ROS towards the cationic surfactant DTB resulted in micel-like structures of equal size, which were spread throughout the solution. With increasing concentrations of DTB larger agglomerates up to network structures were obtained. (orig.) [German] In dieser Arbeit wurden Struktur, Koagulations- und Komplexierungsverhalten von aquatischen refraktaeren organischen Saeuren (ROS) (Humin- und Fulvinsaeuren) charakterisiert. Zu diesem Zweck wurde ein strukturanalytisches Gesamtsystem mit den Methoden Neutronenkleinwinkelstreuung (SANS), Roentgenkleinwinkelstreuung (SAXS) und Roentgenmikroskopie mit Synchrotronstrahlung entwickelt und etabliert. Fuer ROS unterschiedlicher Herkunft in Loesung wurden Groessenverteilungen aus den Streukurven berechnet. Es wurden kugelfoermige ROS-Einheiten gefunden, die bei hoeheren ROS

Kinoform optics applied to X-ray photon correlation spectroscopy.

Science.gov (United States)

Sandy, A R; Narayanan, S; Sprung, M; Su, J-D; Evans-Lutterodt, K; Isakovic, A F; Stein, A

2010-05-01

Moderate-demagnification higher-order silicon kinoform focusing lenses have been fabricated to facilitate small-angle X-ray photon correlation spectroscopy (XPCS) experiments. The geometric properties of such lenses, their focusing performance and their applicability for XPCS measurements are described. It is concluded that one-dimensional vertical X-ray focusing via silicon kinoform lenses significantly increases the usable coherent flux from third-generation storage-ring light sources for small-angle XPCS experiments.

Computer simulation for the effect of target angle in diagnostic x-ray tube output and half-value layer

International Nuclear Information System (INIS)

Hayami, Akimune; Fuchihata, Hajime; Yamazaki, Takeshi; Mori, Yoshinobu; Ozeki, Syuji.

1980-01-01

The change of target angle of X-ray tube plays an important role in changing both the output and the quality of X-rays. A computer simulation was made to estimate the effect of target angle on the output and the quality (half-value layer: HVL) in the central ray using Storm's semiempirical formula. The data here presented are the values of output and HVL for the target angles of 10, 15, 20 and 30 degrees and for the total filtrations of 1, 2, 3 and 4 mm Al eq., at an increment of 10 kV steps of applied voltage between 50 and 150 kV. The output values and HVL's as a function of target angle, applied voltage and total filtration are shown for a full-wave rectified diagnostic X-ray generator. As a result, changes ranging from 17 to 76% in the output and 5 to 66% in the HVL were noted by varying the target angle from 10 to 30 degrees. Therefore, the target angle of X-ray tube should be clearly stated whenever the output and the quality (HVL) of X-ray generator are discussed. (author)

An Assessment of Critical Dimension Small Angle X-ray Scattering Metrology for Advanced Semiconductor Manufacturing

Energy Technology Data Exchange (ETDEWEB)

Settens, Charles M. [State Univ. of New York (SUNY), Albany, NY (United States)

2015-01-01

Simultaneous migration of planar transistors to FinFET architectures, the introduction of a plurality of materials to ensure suitable electrical characteristics, and the establishment of reliable multiple patterning lithography schemes to pattern sub-10 nm feature sizes imposes formidable challenges to current in-line dimensional metrologies. Because the shape of a FinFET channel cross-section immediately influences the electrical characteristics, the evaluation of 3D device structures requires measurement of parameters beyond traditional critical dimension (CD), including their sidewall angles, top corner rounding and footing, roughness, recesses and undercuts at single nanometer dimensions; thus, metrologies require sub-nm and approaching atomic level measurement uncertainty. Synchrotron critical dimension small angle X-ray scattering (CD-SAXS) has unique capabilities to non-destructively monitor the cross-section shape of surface structures with single nanometer uncertainty and can perform overlay metrology to sub-nm uncertainty. In this dissertation, we perform a systematic experimental investigation using CD-SAXS metrology on a hierarchy of semiconductor 3D device architectures including, high-aspect-ratio contact holes, H2 annealed Si fins, and a series of grating type samples at multiple points along a FinFET fabrication process increasing in structural intricacy and ending with fully fabricated FinFET. Comparative studies between CD-SAXS metrology and other relevant semiconductor dimensional metrologies, particularly CDSEM, CD-AFM and TEM are used to determine physical limits of CD-SAXS approach for advanced semiconductor samples. CD-SAXS experimental tradeoffs, advice for model-dependent analysis and thoughts on the compatibility with a semiconductor manufacturing environment are discussed.

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

Understanding nucleic acid structural changes by comparing wide-angle x-ray scattering (WAXS) experiments to molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Pabit, Suzette A.; Katz, Andrea M.; Pollack, Lois [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Tolokh, Igor S. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061 (United States); Drozdetski, Aleksander [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States); Baker, Nathan [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Onufriev, Alexey V. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061 (United States); Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States)

2016-05-28

Wide-angle x-ray scattering (WAXS) is emerging as a powerful tool for increasing the resolution of solution structure measurements of biomolecules. Compared to its better known complement, small angle x-ray scattering (SAXS), WAXS targets higher scattering angles and can enhance structural studies of molecules by accessing finer details of solution structures. Although the extension from SAXS to WAXS is easy to implement experimentally, the computational tools required to fully harness the power of WAXS are still under development. Currently, WAXS is employed to study structural changes and ligand binding in proteins; however, the methods are not as fully developed for nucleic acids. Here, we show how WAXS can qualitatively characterize nucleic acid structures as well as the small but significant structural changes driven by the addition of multivalent ions. We show the potential of WAXS to test all-atom molecular dynamics (MD) simulations and to provide insight into understanding how the trivalent ion cobalt(III) hexammine (CoHex) affects the structure of RNA and DNA helices. We find that MD simulations capture the RNA structural change that occurs due to addition of CoHex.

Small-angle x-ray scattering study on conformation of amorphous polymer chain in the bulk

International Nuclear Information System (INIS)

Hayashi, Hisao; Hamada, Fumiyuki; Nakajima, Akio

1975-01-01

In a previous paper, the new method for the determination of the conformation of polymer chains in concentrated solution and in bulk by small angle X-ray scattering was reported. The purpose of this paper is to estimate the dimension and conformation of polystyrene chains in bulk by this method. The tagged polymer used was the copolymer of styrene and p-iodostyrene. Excess scattering was obtained by subtracting the intensity of polystyrene matrix from that of a mixture containing polystyrene and a small fraction of the tagged polystyrene. Since the excess scattering originates from the group of iodine atoms in the tagged polystyrene, the radius of gyration of the tagged polystyrene is estimated by Guinier plot. Measurement was made with a Kratky camera, and in order to obtain high scattering intensity, the primary beam with line-shaped cross section was used. The intercepts of two limiting curves in the plotted radius of gyration diagram showed good agreement, and the measured molecular dimension agreed with the unperturbed dimension of this polymer. It was concluded that the molecular chains in bulk are mutually penetrable, and the centers of gravity of the molecules distribute almost randomly. It was suggested from the plot of the excess scattering intensity that the conformation of the tagged molecules is a random coil. The present results did not support the ordered structure revealed by bundle model and meander model. (Kako, I.)

Studies on micro-domain structure in segmented polyether polyurethane-ureas by positron annihilation lifetime and small-angle X-ray scattering

International Nuclear Information System (INIS)

Yin Chuanyuan; Gu Qingchao

1997-01-01

The micro-domain structure of segmented polyether polyurethane-ureas is investigated by means of positron annihilation lifetime spectroscopy, small-angle X-ray scattering and differential scanning calorimetry. The experimental results show that the decrease in the domain volume and free volume results from the increase in the hard segment (polyurethane-urea segment) contents as the number-average molecular weight M n -bar of the soft segments (polyethylene glycol segments) is the same, and that the increase in domain volume and free volume result from the increase in the M n -bar of the soft segments when the hard segment content is the same or nearly the same. These results demonstrate that positron annihilation lifetime spectroscopy is a sensitive technique to probe the micro-domain structure in polymers

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)

Determination of structural changes of dispersed clay platelets in a polymer blend during solid-state rheological property measurement by small-angle X-ray scattering

CSIR Research Space (South Africa)

Bandyopadhyay, J

2011-05-01

Full Text Available -angle X-ray scattering studies showed that the degree of anisotropy and mean orientation angles of clay platelets in blend matrix were altered significantly after frequency and temperature sweep tests....

Strain, size and composition of InAs quantum sticks, embedded in InP, determined via X-ray anomalous diffraction and diffraction anomalous fine structure in grazing incidence

International Nuclear Information System (INIS)

Letoublon, A.; Favre-Nicolin, V.; Renevier, H.; Proietti, M.G.; Monat, C.; Gendry, M.; Marty, O.; Priester, C.

2005-01-01

We report on the study of strain, size and composition of small-size encapsulated semiconductor nanostructures. We show that the partial structure factor of As atoms in InAs stick-like nanostructures (quantum sticks), embedded in InP, can be directly extracted from grazing incidence anomalous X-ray diffraction maps at the As K-edge. We have recovered the average height and strain of the islands and determined their composition. The average height of the quantum sticks (QSs), as deduced from the width of the structure factor profile is 2.54 nm. The InAs out of plane deformation, relative to InP, is equal to 6.1%. Fixed-Q anomalous diffraction spectra, measured at the As K-edge, in grazing incidence provide clear evidence of pure InAs QSs. This is confirmed by the analysis of the diffraction anomalous fine structure (DAFS) that also gives a direct way to recover the strain accomodation inside the quantum sticks. Finite difference method calculations reproduce well the diffraction data. Chemical mixing at interfaces is at most 1 ML. This paper shows that ultimate application of anomalous diffraction and DAFS together with reciprocal space maps is a powerful method to sudy the structural properties of nanostructures

Estimation of bearing contact angle in-situ by X-ray kinematography

Science.gov (United States)

Fowler, P. H.; Manders, F.

1982-01-01

The mounted, preloaded contact angle of the structural bearings in the assembled design mechanical assembly was measured. A modification of the Turns method is presented, based upon the clarity and definition of moving parts achieved with X-ray technique and cinematic display. Contact angle is estimated by counting the number of bearings passing a given point as a function of number of turns of the shaft. Ball and pitch diameter variations are discussed. Ball train and shaft angle uncertainties are also discussed.

X-ray diffraction at Bragg angles around π/2

International Nuclear Information System (INIS)

Mayolo, C.M.G. de.

1991-01-01

X-ray diffraction at Bragg angles around π/2 is studied from the theoretical and experimental points of view. The proposed corrections to the dynamical theory in the θ β ≅ π/2 cases, has been reviewed showing the equivalence between two formalisms leading to a corrected expression for the dependence of the angular parameter y with the angle of incidence. An expression for y valid in the conventional and θ β ≅ π/2 cases has been obtained. A general expression for Bragg law and for energy resolution after a Bragg diffraction was also deduced. (author)

X-ray crystal structure and small-angle X-ray scattering of sheep liver sorbitol dehydrogenase

DEFF Research Database (Denmark)

Yennawar, Hemant; Møller, Magda; Gillilan, Richard

2011-01-01

The X-ray crystal structure of sheep liver sorbitol dehydrogenase (slSDH) has been determined using the crystal structure of human sorbitol dehydrogenase (hSDH) as a molecular-replacement model. slSDH crystallized in space group I222 with one monomer in the asymmetric unit. A conserved tetramer...

Modelling of cation displacements in SrTiO.sub.3./sub. by means of multi-energy anomalous X-ray diffuse scattering

Czech Academy of Sciences Publication Activity Database

Kopecký, Miloš; Fábry, Jan; Kub, Jiří

2016-01-01

Roč. 49, Jun (2016), 1016-1020 ISSN 1600-5767 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : X-ray diffuse scattering * atomic displacements * anomalous X-ray scattering * SrTiO 3 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.495, year: 2016

X-ray imaging with toroidal mirror

International Nuclear Information System (INIS)

Aoki, Sadao; Sakayanagi, Yoshimi

1978-01-01

X-ray imaging is made with a single toroidal mirror or two successive toroidal mirrors. Geometrical images at the Gaussian image plane are described by the ray trace. Application of a single toroidal mirror to small-angle scattering is presented. (author)

X-ray spectral determination by detection of radiation scattered at different angles

International Nuclear Information System (INIS)

Barrea, Raul; Mainardi, R.T.

1987-01-01

A precise knowledge of the spectral content of an X-ray beam is of fundamental importance in areas such as X-ray fluorescence analysis by absolute methods, radiodiagnosis, radiotherapy, computed tomography, etc. A simple practical method was developed to determine X-ray spectra emitted by X-ray tubes. It is based on the scattering of the beam on a solid target and detection of this radiation at different angles. This methodology can easily be adapted to the successive attenuation of the beam procedure. Numerical parameter values of a proposed analytical function for the energy spectrum are found measuring the radiation intensity with a suitable detector (ionization chamber or plastic scintillation detector) and equating it with the convolution integral of the proposed spectrum with the incoherent scattering function. This procedure of spectra determination is enclosed in the same group of those generically referred as successive modifications of the irradiation set up used in absolute methods of X-ray fluorescence analysis. (Author) [es

Protein structure determination by single-wavelength anomalous diffraction phasing of X-ray free-electron laser data

Directory of Open Access Journals (Sweden)

Karol Nass

2016-05-01

Full Text Available Serial femtosecond crystallography (SFX at X-ray free-electron lasers (XFELs offers unprecedented possibilities for macromolecular structure determination of systems that are prone to radiation damage. However, phasing XFEL data de novo is complicated by the inherent inaccuracy of SFX data, and only a few successful examples, mostly based on exceedingly strong anomalous or isomorphous difference signals, have been reported. Here, it is shown that SFX data from thaumatin microcrystals can be successfully phased using only the weak anomalous scattering from the endogenous S atoms. Moreover, a step-by-step investigation is presented of the particular problems of SAD phasing of SFX data, analysing data from a derivative with a strong anomalous signal as well as the weak signal from endogenous S atoms.

Plasma-assisted atomic layer epitaxial growth of aluminum nitride studied with real time grazing angle small angle x-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Anderson, Virginia R.; Nepal, Neeraj; Johnson, Scooter D.; Robinson, Zachary R.; Nath, Anindya; Kozen, Alexander C.; Qadri, Syed B.; DeMasi, Alexander; Hite, Jennifer K.; Ludwig, Karl F.; Eddy, Charles R.

2017-05-01

Wide bandgap semiconducting nitrides have found wide-spread application as light emitting and laser diodes and are under investigation for further application in optoelectronics, photovoltaics, and efficient power switching technologies. Alloys of the binary semiconductors allow adjustments of the band gap, an important semiconductor material characteristic, which is 6.2 eV for aluminum nitride (AlN), 3.4 eV for gallium nitride, and 0.7 eV for (InN). Currently, the highest quality III-nitride films are deposited by metalorganic chemical vapor deposition and molecular beam epitaxy. Temperatures of 900 °C and higher are required to deposit high quality AlN. Research into depositing III-nitrides with atomic layer epitaxy (ALEp) is ongoing because it is a fabrication friendly technique allowing lower growth temperatures. Because it is a relatively new technique, there is insufficient understanding of the ALEp growth mechanism which will be essential to development of the process. Here, grazing incidence small angle x-ray scattering is employed to observe the evolving behavior of the surface morphology during growth of AlN by ALEp at temperatures from 360 to 480 °C. Increased temperatures of AlN resulted in lower impurities and relatively fewer features with short range correlations.

Determination by Small-angle X-ray Scattering of Pore Size Distribution in Nanoporous Track-etched Polycarbonate Membranes

Science.gov (United States)

Jonas, A. M.; Legras, R.; Ferain, E.

1998-03-01

Nanoporous track-etched membranes with narrow pore size distributions and average pore size diameters tunable from 100 to 1000 Åare produced by the chemical etching of latent tracks in polymer films after irradiation by a beam of accelerated heavy ions. Nanoporous membranes are used for highly demanding filtration purposes, or as templates to obtain metallic or polymeric nanowires (L. Piraux et al., Nucl. Instr. Meth. Phys. Res. 1997, B131, 357). Such applications call for developments in nanopore size characterization techniques. In this respect, we report on the characterization by small-angle X-ray scattering (SAXS) of nanopore size distribution (nPSD) in polycarbonate track-etched membranes. The obtention of nPSD requires inverting an ill-conditioned inhomogeneous equation. We present different numerical routes to overcome the amplification of experimental errors in the resulting solutions, including a regularization technique allowing to obtain the nPSD without a priori knowledge of its shape. The effect of deviations from cylindrical pore shape on the resulting distributions are analyzed. Finally, SAXS results are compared to results obtained by electron microscopy and conductometry.

Optimization of the x-ray monitoring angle for creating a correlation model between internal and external respiratory signals

Energy Technology Data Exchange (ETDEWEB)

Akimoto, Mami; Nakamura, Mitsuhiro; Mukumoto, Nobutaka; Yamada, Masahiro; Ueki, Nami; Matsuo, Yukinori; Sawada, Akira; Mizowaki, Takashi; Kokubo, Masaki; Hiraoka, Masahiro [Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan and Department of Radiological Technology, Faculty of Medical Science, Kyoto College of Medical Science, Nantan, Kyoto 622-0041 (Japan); Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe, Hyogo 650-0047, Japan and Division of Radiation Oncology, Institute of Biomedical Research and Innovation, Kobe, Hyogo 650-0047 (Japan); Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan)

2012-10-15

Purpose: To perform dynamic tumor tracking irradiation with the Vero4DRT (MHI-TM2000), a correlation model [four dimensional (4D) model] between the displacement of infrared markers on the abdominal wall and the three-dimensional position of a tumor indicated by a minimum of three implanted gold markers is required. However, the gold markers cannot be detected successfully on fluoroscopic images under the following situations: (1) overlapping of the gold markers; and (2) a low intensity ratio of the gold marker to its surroundings. In the present study, the authors proposed a method to readily determine the optimal x-ray monitoring angle for creating a 4D model utilizing computed tomography (CT) images. Methods: The Vero4DRT mounting two orthogonal kV x-ray imaging subsystems can separately rotate the gantry along an O-shaped guide-lane and the O-ring along its vertical axis. The optimal x-ray monitoring angle was determined on CT images by minimizing the root-sum-square of water equivalent path lengths (WEPLs) on the orthogonal lines passing all of the gold markers while rotating the O-ring and the gantry. The x-ray monitoring angles at which the distances between the gold markers were within 5 mm at the isocenter level were excluded to prevent false detection of the gold markers in consideration of respiratory motions. First, the relationship between the WEPLs (unit: mm) and the intensity ratios of the gold markers was examined to assess the validity of our proposed method. Second, our proposed method was applied to the 4D-CT images at the end-expiration phase for 11 lung cancer patients who had four to five gold markers. To prove the necessity of the x-ray monitoring angle optimization, the intensity ratios of the least visible markers (minimum intensity ratios) that were estimated from the WEPLs were compared under the following conditions: the optimal x-ray monitoring angle and the angles used for setup verification. Additionally, the intra- and

3-d chemical imaging using angle-scan nanotomography in a soft X-ray scanning transmission X-ray microscope

Energy Technology Data Exchange (ETDEWEB)

Hitchcock, A.P.; Johansson, G.A. [McMaster, BIMR, Hamilton (Canada); Mitchell, G.E. [Dow Chemical, Analytical Science, Midland, MI (United States); Keefe, M.H. [Dow Chemical, Dow Latex, Midland, MI (United States); Tyliszcak, T. [LBNL, Advanced Light Source, Berkeley, CA (United States)

2008-08-15

Three-dimensional chemical mapping using angle scan nanotomography in a soft X-ray scanning transmission X-ray microscope (STXM) has been used to investigate the spatial distributions of a low density polyacrylate polyelectrolyte ionomer inside submicron sized polystyrene microspheres. Acquisition of tomograms at multiple photon energies provides true, quantifiable 3-d chemical sensitivity. Both pre-O 1s and C 1s results are shown. The study reveals aspects of the 3-d distribution of the polyelectrolyte that were inferred indirectly or had not been known prior to this study. The potential and challenges for extension of the technique to studies of other polymeric and to biological systems is discussed. (orig.)

Conformational variability of the stationary phase survival protein E from Xylella fastidiosa revealed by X-ray crystallography, small-angle X-ray scattering studies, and normal mode analysis.

Science.gov (United States)

Machado, Agnes Thiane Pereira; Fonseca, Emanuella Maria Barreto; Reis, Marcelo Augusto Dos; Saraiva, Antonio Marcos; Santos, Clelton Aparecido Dos; de Toledo, Marcelo Augusto Szymanski; Polikarpov, Igor; de Souza, Anete Pereira; Aparicio, Ricardo; Iulek, Jorge

2017-10-01

Xylella fastidiosa is a xylem-limited bacterium that infects a wide variety of plants. Stationary phase survival protein E is classified as a nucleotidase, which is expressed when bacterial cells are in the stationary growth phase and subjected to environmental stresses. Here, we report four refined X-ray structures of this protein from X. fastidiosa in four different crystal forms in the presence and/or absence of the substrate 3'-AMP. In all chains, the conserved loop verified in family members assumes a closed conformation in either condition. Therefore, the enzymatic mechanism for the target protein might be different of its homologs. Two crystal forms exhibit two monomers whereas the other two show four monomers in the asymmetric unit. While the biological unit has been characterized as a tetramer, differences of their sizes and symmetry are remarkable. Four conformers identified by Small-Angle X-ray Scattering (SAXS) in a ligand-free solution are related to the low frequency normal modes of the crystallographic structures associated with rigid body-like protomer arrangements responsible for the longitudinal and symmetric adjustments between tetramers. When the substrate is present in solution, only two conformers are selected. The most prominent conformer for each case is associated to a normal mode able to elongate the protein by moving apart two dimers. To our knowledge, this work was the first investigation based on the normal modes that analyzed the quaternary structure variability for an enzyme of the SurE family followed by crystallography and SAXS validation. The combined results raise new directions to study allosteric features of XfSurE protein. © 2017 Wiley Periodicals, Inc.

X-ray diffraction study of the structure of detonation nanodiamonds

International Nuclear Information System (INIS)

Ozerin, A. N.; Kurkin, T. S.; Ozerina, L. A.; Dolmatov, V. Yu.

2008-01-01

The spatial structure of aggregates formed by detonation nanodiamonds is investigated using the wide-angle and small-angle X-ray scattering techniques. The effective sizes of crystallites and the crystallite size distribution function are determined. The shape of scattering aggregates is restored from the small-angle X-ray scattering data. An analysis of the results obtained allowed the conclusion that the nanodiamond aggregates have an extended spatial structure composed of nine to ten clusters, each involving four to five crystallites with a crystal lattice of the diamond type

An Accretion Model for Anomalous X-Ray Pulsars

Science.gov (United States)

Chatterjee, Pinaki; Hernquist, Lars; Narayan, Ramesh

2000-05-01

We present a model for the anomalous X-ray pulsars (AXPs) in which the emission is powered by accretion from a fossil disk, established from matter falling back onto the neutron star following its birth. The time-dependent accretion drives the neutron star toward a ``tracking'' solution in which the rotation period of the star increases slowly, in tandem with the declining accretion rate. For appropriate choices of disk mass, neutron star magnetic field strength, and initial spin period, we demonstrate that a rapidly rotating neutron star can be spun down to periods characteristic of AXPs on timescales comparable to the estimated ages of these sources. In other cases, accretion onto the neutron star switches off after a short time and the star becomes an ordinary radio pulsar. Thus, in our picture, radio pulsars and AXPs are drawn from the same underlying population, in contrast to the situation in models involving neutron stars with ultrastrong magnetic fields, which require a new population of stars with very different properties.

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.)

Assessment of Escherichia coli selenophosphate synthetase oligomeric states by analytical ultracentrifugation and small angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Silva, I.R.; Faim, F.M.; Oliveira Neto, M.; Thiemann, O.H. [Universidade de Sao Paulo (USP-SC), Sao Carlos, SP (Brazil); Borges, J.C. [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica

2012-07-01

Full text: Selenium is an essential micronutrient for many organisms and is present in selenium-containing proteins as selenocysteine (Sec) and RNAs as selenouridine. Specific selenium incorporation into selenoproteins and RNAs requires the generation of a biologically active selenium donor compound, selenophosphate, which is produced from the activation of selenide with adenosine 5-triphosphate (ATP) in a reaction catalyzed by Selenophosphate Synthetase (SELD). Therefore, SELD is a key enzyme of the selenium pathway in the cell. The Escherichia coli SELD open reading frame was cloned into pET28a (Novagen) expression vector and the recombinant protein was over expressed in Escherichia coli BL21(DE3) strain. In order to purify the protein, we used metal-chelate affinity chromatography followed by a gel filtration step. Analytical Ultracentrifugation (AUC) and Small Angle X-ray Scattering (SAXS) were employed to study the oligomeric states of the soluble protein. The results of AUC revealed dimer-tetramer and tetramer-octamer equilibrium at low concentrations of protein, with dissociation constants of 70 2 and 560 40 M, respectively. Moreover, the SAXS results pointed the oligomeric state of the protein at higher concentrations as predominantly dimeric and the p(r) and the SAXS envelope revealed the SELD as elongated. We also performed initial crystallization trials with protein samples at 7 mg/ml in 96-well sitting-drop crystallization plates at room temperature using a crystallization robot. Needle crystals appeared after some days. X-ray diffraction for these crystals were tested in the MX2 beamline at the Brazilian Synchrotron Laboratory (LNLS Campinas). We are now working to improve these crystals in order to obtain suitable crystals for structure determination. (author)

Small-Size High-Current Generators for X-Ray Backlighting

Science.gov (United States)

Chaikovsky, S. A.; Artyomov, A. P.; Zharova, N. V.; Zhigalin, A. S.; Lavrinovich, I. V.; Oreshkin, V. I.; Ratakhin, N. A.; Rousskikh, A. G.; Fedunin, A. V.; Fedushchak, V. F.; Erfort, A. A.

2017-12-01

The paper deals with the soft X-ray backlighting based on the X-pinch as a powerful tool for physical studies of fast processes. Proposed are the unique small-size pulsed power generators operating as a low-inductance capacitor bank. These pulse generators provide the X-pinch-based soft X-ray source (hν = 1-10 keV) of micron size at 2-3 ns pulse duration. The small size and weight of pulse generators allow them to be transported to any laboratory for conducting X-ray backlighting of test objects with micron space resolution and nanosecond exposure time. These generators also allow creating synchronized multi-frame radiographic complexes with frame delay variation in a broad range.

Structure of a mouse immunoglobulin G that lacks the entire CH1 domain: Protein sequencing and small-angle X-ray scattering studies

International Nuclear Information System (INIS)

Igarashi, Takako; Tanaka, Toshiyuki; Nakanishi, Mamoru; Arata, Yoji; Sato, Mamoru; Katsube, Yukiteru; Takio, Koji

1990-01-01

The structure of a short-chain IgG2a antibody, which is a member of the family of mouse anti-dansyl switch variant antibodies with identical variable regions but different heavy-chain constant regions, is reported. Amino acid sequencing analyses have demonstrated that in the short-chain IgG2a antibody the entire C H 1 domain is deleted whereas the hinge region remains intact. Small-angle X-ray scattering data were collected for the short-chain IgG2a antibody and compared with those for the switch variant IgG1, IgG2a, and IgG2b antibodies with the normal heavy chain. It has been concluded that deletion of the C H 1 domain results in a large structural change and the short-chain IgG2a antibody possesses an elongated molecular shape with a much smaller hinge angle as compared with the normal IgG2a antibody that is a Y-shaped molecule

REX - a program for the analysis of X-ray reflectivity data: user guide and programmer manual

International Nuclear Information System (INIS)

Crabb, T.A.; Gibson, P.N.

1992-12-01

A FORTRAN program REX, which has been developed to facilitate the interpretation of X-ray reflectivity data, is described. The program allows the simulation of reflectivity profiles as a function of either incident angle or of energy. Factors such as anomalous dispersion, and surface and interface roughness are taken into account in the model. In addition, experimental data of reflectivity as a function of incident angle can be matched to user-supplied theoretical parameters by a least-squares refinement procedure. Experimental reflectivity data recorded at several X-ray wavelengths can be analysed simultaneously, thus eliminating certain experimental errors. (author)

Transformation from Multilamellar to Unilamellar Vesicles by Addition of a Cationic Lipid to PEGylated Liposomes Explored with Synchrotron Small Angle X-ray Scattering

International Nuclear Information System (INIS)

Sakuragi, Mina; Sakurai, Kazuo; Koiwai, Kazunori; Nakamura, Kouji; Masunaga, Hiroyasu; Ogawa, Hiroki

2011-01-01

PEGylated liposomes composed of a benzamidine derivative (TRX), hydrogenated soybean phosphatidylcholine (HSPC), and N-(monomethoxy-polyethyleneglycolcarbamyl) distearoyl phosphatidylethanolamine (PEG-PE) were examined in terms of how the addition of TRX affects their structures with small angle x-ray scattering (SAXS) as well as transmission electron microscopy (TEM). TEM images showed the presence of unilamella vesicles for both with and without TRX, though a small amount of multilamella vesicles were observed in absence of TRX. We analyzed SAXS profiles at contained TRX composition combined with contrast variation technique by adding PEG solution and unilamella vesicle model could be reproduced. Subsequently, we analyzed SAXS profiles at no TRX composition. The mixture model of unilamella and multilamella vesicle was reconstructed and we estimated about 10 % multilamella vesicles from a fitting parameter.

Crystal structure determination of solar cell materials: Cu2ZnSnS4 thin films using X-ray anomalous dispersion

International Nuclear Information System (INIS)

Nozaki, Hiroshi; Fukano, Tatsuo; Ohta, Shingo; Seno, Yoshiki; Katagiri, Hironori; Jimbo, Kazuo

2012-01-01

Highlights: ► Cu 2 ZnSnS 4 thin films as a solar cell material were synthesized. ► The wavelength dependences of the diffraction intensity were measured. ► The crystal structures were clearly identified as kesterite structure for all samples. ► Crystal structure analysis revealed that the atomic compositions were Cu/(Zn + Sn) = 0.97 and Zn/Sn = 1.42 for the sample synthesized using stoichiometric amount of starting materials. - Abstract: The crystal structure of Cu 2 ZnSnS 4 (CZTS) thin films fabricated by vapor-phase sulfurization was determined using X-ray anomalous dispersion. High statistic synchrotron radiation X-ray diffraction data were collected from very small amounts of powder. By analyzing the wavelength dependencies of the diffraction peak intensities, the crystal structure was clearly identified as kesterite. Rietveld analysis revealed that the atomic composition deviated from stoichiometric composition, and the compositions were Cu/(Zn + Sn) = 0.97, and Zn/Sn = 1.42.

Determination of transition metal ion distribution in cubic spinel Co1.5Fe1.5O4 using anomalous x-ray diffraction

Directory of Open Access Journals (Sweden)

M. N. Singh

2015-08-01

Full Text Available We report anomalous x-ray diffraction studies on Co ferrite with composition Co1.5Fe1.5O4 to obtain the distribution of transition metal ions in tetrahedral and octahedral sites. We synthesize spinel oxide (Co1.5Fe1.5O4 through co-precipitation and subsequent annealing route. The imaginary part (absorption of the energy dependent anomalous form factor is measured and the real part is calculated theoretically through Kramers–Krönig transformation to analyze anomalous x-ray diffraction peak intensities. Fe and Co K-edge x-ray absorption near edge structure (XANES spectra are used to estimate charge states of transition metals. Our analysis, within experimental errors, suggests 44% of the tetrahedral sites contain Co in +2 oxidation state and the rest 56% sites contain Fe in +2 and +3 oxidation states. Similarly, 47% of the octahedral sites contain Fe in +3 oxidation states, whereas, the rest of the sites contain Co in +2 and +3 oxidation states. While a distinct pre-edge feature in the Fe K-edge XANES is observed, Co pre-edge remains featureless. Implications of these results to magnetism are briefly discussed.

Analysis of thin films prepared by vacuum-evaporation and dropping solution by Takeoff Angle-Dependent X-Ray Fluorescence spectroscopy at glancing incidence

International Nuclear Information System (INIS)

Tsuji, Kouichi; Hirokawa, Kichinosuke; Mitose, Kengo.

1995-01-01

We have introduced Takeoff Angle-Dependent X-Ray Fluorescence (TAD-XRF) method for thin film and surface analysis. In this method, the sample on the optically flat substrate is irradiated with the glancing incidence of the primary X-ray, and the fluorescent X-rays emitted from the sample are detected at the glancing takeoff angle. We had previously calculated the relationship between the fluorescent X-ray intensity and the takeoff angle at the glancing incidence. The characterization of the thin film is achieved by investigating the dependence of the fluorescent X-ray intensity on the takeoff angle with the calculated curve. Using this analytical method, we have reported the results of the TAD-XRF measured for the evaporated thin films and the dried films from dropping solution in this paper. The effect of the thickness of the thin film, the density of the substrate and the incident angle on the TAD-XRF curve has been reported. In the case of the dried film from the dropping solution, a broad peak was observed at the takeoff angle which was close to the critical angle for the total reflection of the fluorescent X-ray in the TAD-XRF curve. This broad peak was explained by the double-excitation of the incident beam and the refracted beam of the fluorescent X-ray with the assumption that the X-ray which has a same wavelength to the observed fluorescent X-ray impinges upon the sample surface, because the reciprocity theorem is expected in the X-ray region. (author)

Fluid adsorption in ordered mesoporous solids determined by in situ small-angle X-ray scattering.

Science.gov (United States)

Findenegg, Gerhard H; Jähnert, Susanne; Müter, Dirk; Prass, Johannes; Paris, Oskar

2010-07-14

The adsorption of two organic fluids (n-pentane and perfluoropentane) in a periodic mesoporous silica material (SBA-15) is investigated by in situ small-angle X-ray scattering (SAXS) using synchrotron radiation. Structural changes are monitored as the ordered and disordered pores in the silica matrix are gradually filled with the fluids. The experiments yield integrated peak intensities from up to ten Bragg reflections from the 2D hexagonal pore lattice, and additionally diffuse scattering contributions arising from disordered (mostly intrawall) porosity. The analysis of the scattering data is based on a separation of these two contributions. Bragg scattering is described by adopting a form factor model for ordered pores of cylindrical symmetry which accounts for the filling of the microporous corona, the formation of a fluid film at the pore walls, and condensation of the fluid in the core. The filling fraction of the disordered intrawall pores is extracted from the diffuse scattering intensity and its dependence on the fluid pressure is analyzed on the basis of a three-phase model. The data analysis introduced here provides an important generalisation of a formalism presented recently (J. Phys. Chem. C, 2009, 13, 15201), which was applicable to contrast-matching fluids only. In this way, the adsorption behaviour of fluids into ordered and disordered pores in periodic mesoporous materials can be analyzed quantitatively irrespective of the fluid density.

Theoretical concepts of X-ray nanoscale analysis theory and applications

CERN Document Server

Benediktovitch, Andrei; Ulyanenkov, Alexander

2013-01-01

This book provides a concise survey of modern theoretical concepts of X-ray materials analysis. The principle features of the book are: basics of X-ray scattering, interaction between X-rays and matter and new theoretical concepts of X-ray scattering. The various X-ray techniques are considered in detail: high-resolution X-ray diffraction, X-ray reflectivity, grazing-incidence small-angle X-ray scattering and X-ray residual stress analysis. All the theoretical methods presented use the unified physical approach. This makes the book especially useful for readers learning and performing data ana

BioXTAS RAW, a software program for high-throughput automated small-angle X-ray scattering data reduction and preliminary analysis

DEFF Research Database (Denmark)

Nielsen, S.S.; Toft, K.N.; Snakenborg, Detlef

2009-01-01

A fully open source software program for automated two-dimensional and one-dimensional data reduction and preliminary analysis of isotropic small-angle X-ray scattering (SAXS) data is presented. The program is freely distributed, following the open-source philosophy, and does not rely on any...... commercial software packages. BioXTAS RAW is a fully automated program that, via an online feature, reads raw two-dimensional SAXS detector output files and processes and plots data as the data files are created during measurement sessions. The software handles all steps in the data reduction. This includes...... mask creation, radial averaging, error bar calculation, artifact removal, normalization and q calibration. Further data reduction such as background subtraction and absolute intensity scaling is fast and easy via the graphical user interface. BioXTAS RAW also provides preliminary analysis of one...

Measurements of accurate x-ray scattering data of protein solutions using small stationary sample cells

Science.gov (United States)

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.

Measurements of accurate x-ray scattering data of protein solutions using small stationary sample cells

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.

A novel application of small-angle scattering techniques: Quality assurance testing of virus quantification technology

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

Dimensions and Global Twist of Single-Layer DNA Origami Measured by Small-Angle X-ray Scattering.

Science.gov (United States)

Baker, Matthew A B; Tuckwell, Andrew J; Berengut, Jonathan F; Bath, Jonathan; Benn, Florence; Duff, Anthony P; Whitten, Andrew E; Dunn, Katherine E; Hynson, Robert M; Turberfield, Andrew J; Lee, Lawrence K

2018-06-04

The rational design of complementary DNA sequences can be used to create nanostructures that self-assemble with nanometer precision. DNA nanostructures have been imaged by atomic force microscopy and electron microscopy. Small-angle X-ray scattering (SAXS) provides complementary structural information on the ensemble-averaged state of DNA nanostructures in solution. Here we demonstrate that SAXS can distinguish between different single-layer DNA origami tiles that look identical when immobilized on a mica surface and imaged with atomic force microscopy. We use SAXS to quantify the magnitude of global twist of DNA origami tiles with different crossover periodicities: these measurements highlight the extreme structural sensitivity of single-layer origami to the location of strand crossovers. We also use SAXS to quantify the distance between pairs of gold nanoparticles tethered to specific locations on a DNA origami tile and use this method to measure the overall dimensions and geometry of the DNA nanostructure in solution. Finally, we use indirect Fourier methods, which have long been used for the interpretation of SAXS data from biomolecules, to measure the distance between DNA helix pairs in a DNA origami nanotube. Together, these results provide important methodological advances in the use of SAXS to analyze DNA nanostructures in solution and insights into the structures of single-layer DNA origami.

A modulated differential scanning calorimetry and small-angle x-ray scattering study of the interfacial region in structured latices

Directory of Open Access Journals (Sweden)

Hourston Douglas J.

2001-01-01

Full Text Available The interfacial structure of poly(styrene (PS-poly(methyl acrylate (PMA structured latices has been investigated by means of modulated-temperature differential scanning calorimetry (M-TDSC and small-angle x-ray scattering (SAXS. The differential of heat capacity, dCp/dT, signal from M-TDSC was used to quantify the weight fraction of interface in these latices. For PS-PMA (50:50 by weight structured latices in which the PS component had different crosslink densities (0, 1, 3, 5 and 10 mol% of crosslinking agent, the weight fraction of interface was about 13%. With increasing crosslink density, the fraction of interface increased only slightly. A core-shell model has been used to analyse SAXS data for these PS-PMA latices. M-TDSC can only provide information about the weight fraction of interface, but the combination of M-TDSC and SAXS can provide much more information on the morphology of such structured latices.

Study on the conformal variations of bovine and human serum albumin in solution using small angle X-ray scattering

International Nuclear Information System (INIS)

Olivieri, Johnny Rizzieri.

1992-01-01

It is reported a Small Angle X-Ray Scattering (SAXS) study of BSA (Bovine Serum Albumin) and HSA (Human Serum Albumin) on pH between 2.5 and 7.0. The measured scattering intensities, normalized in relation to incident beam, exposition time and scattering due to solvent and capillary, and corrected due to concentration and beam shape effects, have shown a strong dependence of the protein shape with pH for both albumins. It was found that the radius of gyration varies between 26.7 and 35 A, and the analyses of the distance distribution function. P(r), indicated that these proteins undergoes conformational changes with pH. Different theoretical shapes have been proposed and analysed comparing the computed P(r) function generated from the models with the experimental P(r). A large variety of shapes were found in both proteins, indicating that BSA and HSA are very flexibility macromolecules. (author). 60 refs., 49 figs., 7 tabs

Structure of human low-density lipoprotein subfractions, determined by X-ray small-angle scattering.

Science.gov (United States)

Baumstark, M W; Kreutz, W; Berg, A; Frey, I; Keul, J

1990-01-19

The structure of low-density lipoprotein (LDL) particles from three different density ranges (LDL-1: d = 1.006-1.031 g/ml; LDL-3: d = 1.034-1.037 g/ml; LDL-6: d = 1.044-1.063 g/ml) was determined by X-ray small-angle scattering. By using a theoretical particle model, which accounted for the polydispersity of the samples, we were able to obtain fits of the scattering intensity that were inside the noise interval of the measured intensity. The assumption of deviations from radial symmetry is not supported by our data. This implies a spread-out conformation of the apolipoprotein B (apoB) molecule, which appears to be localized in the outer surface shell. A globular structure is not consistent with our data. Furthermore, different models exist concerning the structure of the cholesterol ester core below the phase transition temperature. The electron density data suggest an arrangement in which the steroid moieties are localized at average radii of 3.2 and 6.4 nm. Model calculations show that packing problems can only be avoided if approximately half of the acyl chains of each shell are pointing towards the center of the particle, the other half towards the surface. This arrangement of the acyl chains has never been proposed before. The LDL particles of different density classes differ mainly with respect to the size of the core but also with respect to the width of the surface shells. Model calculations show that the size of different LDL particles can be accurately predicted from the compositional data.

Structural characterization of the human cerebral myelin sheath by small angle x-ray scattering

International Nuclear Information System (INIS)

De Felici, M; Felici, R; Ferrero, C; Tartari, A; Gambaccini, M; Finet, S

2008-01-01

Myelin is a multi-lamellar membrane surrounding neuronal axons and increasing their conduction velocity. When investigated by small-angle x-ray scattering (SAXS), the lamellar quasi-periodical arrangement of the myelin sheath gives rise to distinct peaks, which allow the determination of its molecular organization and the dimensions of its substructures. In this study we report on the myelin sheath structural determination carried out on a set of human brain tissue samples coming from surgical biopsies of two patients: a man around 60 and a woman nearly 90 years old. The samples were extracted either from white or grey cerebral matter and did not undergo any manipulation or chemical-physical treatment, which could possibly have altered their structure, except dipping them into a formalin solution for their conservation. Analysis of the scattered intensity from white matter of intact human cerebral tissue allowed the evaluation not only of the myelin sheath periodicity but also of its electronic charge density profile. In particular, the thicknesses of the cytoplasm and extracellular regions were established, as well as those of the hydrophilic polar heads and hydrophobic tails of the lipid bilayer. SAXS patterns were measured at several locations on each sample in order to establish the statistical variations of the structural parameters within a single sample and among different samples. This work demonstrates that a detailed structural analysis of the myelin sheath can also be carried out in randomly oriented samples of intact human white matter, which is of importance for studying the aetiology and evolution of the central nervous system pathologies inducing myelin degeneration.

Repeated sorption of water in SBA-15 investigated by means of in situ small-angle x-ray scattering

International Nuclear Information System (INIS)

Erko, M; Paris, O; Wallacher, D; Findenegg, G H

2012-01-01

The effect of repeated cycles of water adsorption/desorption on the structural stability of ordered mesoporous silica SBA-15 is studied by small-angle x-ray scattering (SAXS). In situ sorption measurements are conducted using a custom-built sorption apparatus in connection with a laboratory SAXS setup. Two striking irreversible changes are observed in the sorption isotherms as derived from the integrated SAXS intensity. First, the capillary condensation pressure shifts progressively to lower relative pressure values with increasing number of sorption cycles. This effect is attributed to chemisorption of water at the silica walls, resulting in a change of the fluid-wall interaction. Second, the sorption cycles do not close completely at vanishing vapour pressure, suggesting that progressively more water remains trapped within the porous material after each cycle. This effect is interpreted to be the result of an irreversible collapse of parts of mesopores, originating from pore wall deformation due to the large Laplace pressure of water acting on the pore walls at capillary condensation and capillary evaporation. (paper)

The atomic scale structure of CXV carbon: wide-angle x-ray scattering and modeling studies.

Science.gov (United States)

Hawelek, L; Brodka, A; Dore, J C; Honkimaki, V; Burian, A

2013-11-13

The disordered structure of commercially available CXV activated carbon produced from finely powdered wood-based carbon has been studied using the wide-angle x-ray scattering technique, molecular dynamics and density functional theory simulations. The x-ray scattering data has been converted to the real space representation in the form of the pair correlation function via the Fourier transform. Geometry optimizations using classical molecular dynamics based on the reactive empirical bond order potential and density functional theory at the B3LYP/6-31g* level have been performed to generate nanoscale models of CXV carbon consistent with the experimental data. The final model of the structure comprises four chain-like and buckled graphitic layers containing a small percentage of four-fold coordinated atoms (sp(3) defects) in each layer. The presence of non-hexagonal rings in the atomic arrangement has been also considered.

Solution small-angle x-ray scattering as a screening and predictive tool in the fabrication of asymmetric block copolymer membranes

KAUST Repository

Dorin, Rachel Mika; Marques, Debora S.; Sai, Hiroaki; Vainio, Ulla; Phillip, William A.; Peinemann, Klaus; Nunes, Suzana Pereira; Wiesner, Ulrich B.

2012-01-01

Small-angle X-ray scattering (SAXS) analysis of the diblock copolymer poly(styrene-b-(4-vinyl)pyridine) in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and N,N-dimethylformamide, and the triblock terpolymer poly(isoprene-b-styrene-b-(4-vinyl)-pyridine) in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure. These results suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure in the fabrication of asymmetric ultrafiltration membranes from self-assembled block copolymers. (Figure presented) © 2012 American Chemical Society.

Solution small-angle x-ray scattering as a screening and predictive tool in the fabrication of asymmetric block copolymer membranes

KAUST Repository

Dorin, Rachel Mika

2012-05-15

Small-angle X-ray scattering (SAXS) analysis of the diblock copolymer poly(styrene-b-(4-vinyl)pyridine) in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and N,N-dimethylformamide, and the triblock terpolymer poly(isoprene-b-styrene-b-(4-vinyl)-pyridine) in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure. These results suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure in the fabrication of asymmetric ultrafiltration membranes from self-assembled block copolymers. (Figure presented) © 2012 American Chemical Society.

Development of small scale soft x-ray lasers

International Nuclear Information System (INIS)

Kim, D.; Suckewer, S.; Princeton Univ., NJ; Skinner, C.H.; Voorhees, D.

1991-05-01

At present rapid progress is being made in the application of soft x-ray lasers to fields such as microscopy and microlithography. A critical factor in the range of suitable applications is the scale and hence cost of the soft x-ray lasers. At Princeton, gain at 183 angstrom has been obtained with relatively low pump laser energies (as low as 6J) in a ''portable'' small-scale soft x-ray laser system. We will also discuss aspects of data interpretation and pitfalls to be avoided in measurements of gain in such systems. 14 refs., 7 figs

Elasticity of Tantalum to 105 Gpa using a stress and angle-resolved x-ray diffraction

International Nuclear Information System (INIS)

Cynn, H; Yoo, C S

1999-01-01

Determining the mechanical properties such as elastic constants of metals at Mbar pressures has been a difficult task in experiment. Following the development of anisotropic elastic theory by Singh et al.[l], Mao et a1.[2] have recently developed a novel experimental technique to determine the elastic constants of Fe by using the stress and energy-dispersive x-ray diffraction (SEX). In this paper, we present an improved complementary technique, stress and angle-resolved x-ray diffraction (SAX), which we have applied to determine the elastic constants of tantalum to 105 GPa. The extrapolation of the tantalum elastic data shows an excellent agreement with the low-pressure ultrasonic data[3]. We also discuss the improvement of this SAX method over the previous SEX.[elastic constant, anisotropic elastic theory, angle-dispersive synchrotron x-ray diffraction, mechanical properties

Monitoring the recrystallisation of amorphous xylitol using Raman spectroscopy and wide-angle X-ray scattering.

Science.gov (United States)

Palomäki, Emmi; Ahvenainen, Patrik; Ehlers, Henrik; Svedström, Kirsi; Huotari, Simo; Yliruusi, Jouko

2016-07-11

In this paper we present a fast model system for monitoring the recrystallization of quench-cooled amorphous xylitol using Raman spectroscopy and wide-angle X-ray scattering. The use of these two methods enables comparison between surface and bulk crystallization. Non-ordered mesoporous silica micro-particles were added to the system in order to alter the rate of crystallization of the amorphous xylitol. Raman measurements showed that adding silica to the system increased the rate of surface crystallization, while X-ray measurements showed that the rate of bulk crystallization decreased. Using this model system it is possible to measure fast changes, which occur in minutes or within a few hours. Raman-spectroscopy and wide-angle X-ray scattering were found to be complementary techniques when assessing surface and bulk crystallization of amorphous xylitol. Copyright © 2016 Elsevier B.V. All rights reserved.

Pepsi-SAXS: an adaptive method for rapid and accurate computation of small-angle X-ray scattering profiles.

Science.gov (United States)

Grudinin, Sergei; Garkavenko, Maria; Kazennov, Andrei

2017-05-01

A new method called Pepsi-SAXS is presented that calculates small-angle X-ray scattering profiles from atomistic models. The method is based on the multipole expansion scheme and is significantly faster compared with other tested methods. In particular, using the Nyquist-Shannon-Kotelnikov sampling theorem, the multipole expansion order is adapted to the size of the model and the resolution of the experimental data. It is argued that by using the adaptive expansion order, this method has the same quadratic dependence on the number of atoms in the model as the Debye-based approach, but with a much smaller prefactor in the computational complexity. The method has been systematically validated on a large set of over 50 models collected from the BioIsis and SASBDB databases. Using a laptop, it was demonstrated that Pepsi-SAXS is about seven, 29 and 36 times faster compared with CRYSOL, FoXS and the three-dimensional Zernike method in SAStbx, respectively, when tested on data from the BioIsis database, and is about five, 21 and 25 times faster compared with CRYSOL, FoXS and SAStbx, respectively, when tested on data from SASBDB. On average, Pepsi-SAXS demonstrates comparable accuracy in terms of χ 2 to CRYSOL and FoXS when tested on BioIsis and SASBDB profiles. Together with a small allowed variation of adjustable parameters, this demonstrates the effectiveness of the method. Pepsi-SAXS is available at http://team.inria.fr/nano-d/software/pepsi-saxs.

Surface and interface strains studied by x-ray diffraction

International Nuclear Information System (INIS)

Akimoto, Koichi; Emoto, Takashi; Ichimiya, Ayahiko

1998-01-01

The authors have developed a technique of X-ray diffraction in order to measure strain fields near semiconductor surface and interface. The diffraction geometry is using the extremely asymmetric Bragg-case bulk reflection of a small incident angle to the surface and a large angle exiting from the surface. The incident angle of the X-rays is set near critical angle of total reflection by tuning X-ray energy of synchrotron radiation at the Photon Factory, Japan. For thermally grown-silicon oxide/Si(100) interface, the X-ray intensity of the silicon substrate 311 reflection has been measured. From comparison of the full width at half maxima (FWHM) of X-ray rocking curves of various thickness of silicon oxides, it has been revealed that silicon substrate lattice is highly strained in the thin (less than about 5 nm) silicon oxide/silicon system. In order to know the original silicon surface strain, the authors have also performed the same kind of measurements in the ultra-high vacuum chamber. A clean Si(111) 7x7 surface gives sharper X-ray diffraction peak than that of the native oxide/Si(111) system. From these measurements, it is concluded that the thin silicon oxide film itself gives strong strain fields to the silicon substrates, which may be the reason of the existence of the structural transition layer at the silicon oxide/Si interface

Residual stress analysis on materials with steep stress gradient by using X-ray incidence at higher angles

International Nuclear Information System (INIS)

Ohya, Shin-ichi; Yoshioka, Yasuo; Maeno, Shigeki

1996-01-01

X-ray stress measurements for isotropic polycrystalline are materials are usually carried out by the sin 2 ψ method under the assumption of no stress gradient in X-ray penetration depth. When a steep stress gradient exists in the vicinity of surface layer, however, non-linear sin 2 ψ relation is observed and the sin 2 ψ method cannot be applied on such cases. Although several X-ray stress analyzers have been developed for materials with steep stress gradient in the surface layer, it is desirable to use diffraction data at higher incident angles of ψ 0 as possible as close on 90 degrees in order to determine the both values of surface stress and stress gradient with high accuracy. In the present study, an X-ray stress analyzer based on Ω geometry was fabricated to enable X-ray incidence at higher angle of ψ 0 . The X-ray detector was positioned on -η side against X-ray incident beam. Both of the residual surface stress and stress gradient were determined by use of the COSψ method on shot-peened steel and silicon nitride specimens. This prototype stress analyzer was found effective to perform a biaxial or triaxial stress analysis. (author)

Investigation of the topological shape of bovine serum albumin in solution by small-angle x-ray scattering at Beijing synchrotron radiation facility

International Nuclear Information System (INIS)

Dong Shuqiang; Chen Ximeng; Li Liqin; Liu Peng; Dong Yuhui

2008-01-01

This paper reports that at a newly constructed small-angle x-ray scattering station of Beijing Synchrotron Radiation Facility, the topological shape of ligand-free bovine serum albumin in solution has been investigated. An appropriate scattering curve is obtained and the calculated value of the gyration radius is 31.2ű0.25A (1Å=0.1 nm) which is coincident with other ones' results. It finds that the low-resolution structure models obtained by making use of ab initio reconstruction methods are fitting the crystal structure of human serum albumin very well. All of these results perform the potential of the beamline to apply to structural biology studies. The characteristics, the defects, and the improving measures of the station in future are also discussed. (condensed matter: structure, thermal and mechanical properties)

Small-angle X-ray scattering documents the growth of metal-organic frameworks

NARCIS (Netherlands)

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

BioXTAS RAW: improvements to a free open-source program for small-angle X-ray scattering data reduction and analysis.

Science.gov (United States)

Hopkins, Jesse Bennett; Gillilan, Richard E; Skou, Soren

2017-10-01

BioXTAS RAW is a graphical-user-interface-based free open-source Python program for reduction and analysis of small-angle X-ray solution scattering (SAXS) data. The software is designed for biological SAXS data and enables creation and plotting of one-dimensional scattering profiles from two-dimensional detector images, standard data operations such as averaging and subtraction and analysis of radius of gyration and molecular weight, and advanced analysis such as calculation of inverse Fourier transforms and envelopes. It also allows easy processing of inline size-exclusion chromatography coupled SAXS data and data deconvolution using the evolving factor analysis method. It provides an alternative to closed-source programs such as Primus and ScÅtter for primary data analysis. Because it can calibrate, mask and integrate images it also provides an alternative to synchrotron beamline pipelines that scientists can install on their own computers and use both at home and at the beamline.

A small angle X-ray scattering method to investigate the crack tip in metals. Final report of the Marie Curie individual fellowship project

International Nuclear Information System (INIS)

Ouytsel, K. van; Boehmert, J.; Mueller, G.

2003-08-01

Structural materials, such as ferritic and austenitic steels or aluminium alloys used in the nuclear and aircraft industry, are subjected to external operational loads in different environments. Adopting a damage tolerant design principle, understanding the growth of preexisting or newly formed cracks under these conditions is of prime relevance to prevent extensive crack propagation and failure of the component. Within this framework, the characterization of early stages of the damage processes, as nucleation, growth and coalescence of micro-voids and the evolution of the spatial dislocation distribution (dislocation patterning) is a particularly challenging aspect. It was the objective of the work performed to investigate the damage structure near a crack tip by means of small angle X-ray scattering (SAXS). Pre-cracked fracture mechanics standard specimens from different aluminium alloys and steels were loaded up to different amounts of crack growth. From the crack tip range samples of 100 to 200 μm thickness were prepared and a small region around the crack tip was scanned using a microfocused Synchrotron beam. The SAXS experiments were performed at different Synchrotron sources and equipments with different beam cross section, scan step width and X-ray energy. Additionally, the investigation was completed by other methods like X-ray diffraction, X-ray imaging diffraction technique (MAXIM), transmission electron microscopy, scanning electron microscopy, and positron annihilation spectroscopy. The SAXS intensity pattern shows location-related effects. Potential SAXS parameters to characterize the damage are the integral intensity, a fractal dimension parameter and a value determined from the ratio of the intensity vertical and horizontal to the direction of crack growth. Above all, the last parameter is suitable to depict the damage zone around the crack tip. It is robust and applicable even for a material which exhibits an anisotropic SAXS pattern in the

X-ray diagnostic in gas discharge

International Nuclear Information System (INIS)

Chen Suhe; Wang Dalun; Cui Gaoxian; Wang Mei; Fu Yibei; Zhang Xinwei; Zhang Wushou

1995-01-01

X rays were observed when the anomalous phenomenon in the metal loaded with deuterium studied by the gas-discharge method. Therefore the X-ray energy spectra were measured by the absorption method, the specific X-ray approach and the NaI scintillation counter, while X-ray intensity was estimated by using 7 Li thermoluminescent foils. The X-ray average energy measured by the absorption method is 27.6 +- 2.1 keV, which is fitted within the error extent to 26.0 +-2.4 keV monoenergetic X rays measured by the NaI scintillation counter

Anomalous incident-angle and elliptical-polarization rotation of an elastically refracted P-wave

Science.gov (United States)

Fa, Lin; Fa, Yuxiao; Zhang, Yandong; Ding, Pengfei; Gong, Jiamin; Li, Guohui; Li, Lijun; Tang, Shaojie; Zhao, Meishan

2015-08-01

We report a newly discovered anomalous incident-angle of an elastically refracted P-wave, arising from a P-wave impinging on an interface between two VTI media with strong anisotropy. This anomalous incident-angle is found to be located in the post-critical incident-angle region corresponding to a refracted P-wave. Invoking Snell’s law for a refracted P-wave provides two distinctive solutions before and after the anomalous incident-angle. For an inhomogeneously refracted and elliptically polarized P-wave at the anomalous incident-angle, its rotational direction experiences an acute variation, from left-hand elliptical to right-hand elliptical polarization. The new findings provide us an enhanced understanding of acoustical-wave scattering and lead potentially to widespread and novel applications.

Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study

Directory of Open Access Journals (Sweden)

Takatsugu Endo

2017-01-01

Full Text Available We investigated nano-structural changes of cellulose dissolved in 1-ethyl-3-methylimidazolium acetate—an ionic liquid (IL—using a small angle X-ray scattering (SAXS technique over the entire concentration range (0–100 mol %. Fibril structures of cellulose disappeared at 40 mol % of cellulose, which is a significantly higher concentration than the maximum concentration of dissolution (24–28 mol % previously determined in this IL. This behavior is explained by the presence of the anion bridging, whereby an anion prefers to interact with multiple OH groups of different cellulose molecules at high concentrations, discovered in our recent work. Furthermore, we observed the emergence of two aggregated nano-structures in the concentration range of 30–80 mol %. The diameter of one structure was 12–20 nm, dependent on concentration, which is ascribed to cellulose chain entanglement. In contrast, the other with 4.1 nm diameter exhibited concentration independence and is reminiscent of a cellulose microfibril, reflecting the occurrence of nanofibrillation. These results contribute to an understanding of the dissolution mechanism of cellulose in ILs. Finally, we unexpectedly proposed a novel cellulose/IL composite: the cellulose/IL mixtures of 30–50 mol % that possess liquid crystallinity are sufficiently hard to be moldable.

Structure of a mouse immunoglobulin G that lacks the entire C sub H 1 domain: Protein sequencing and small-angle X-ray scattering studies

Energy Technology Data Exchange (ETDEWEB)

Igarashi, Takako; Tanaka, Toshiyuki; Nakanishi, Mamoru; Arata, Yoji (Univ. of Tokyo (Japan)); Sato, Mamoru; Katsube, Yukiteru (Osaka Univ. (Japan)); Takio, Koji (Institute of Physical and Chemical Research, Saitama (Japan))

1990-06-19

The structure of a short-chain IgG2a antibody, which is a member of the family of mouse anti-dansyl switch variant antibodies with identical variable regions but different heavy-chain constant regions, is reported. Amino acid sequencing analyses have demonstrated that in the short-chain IgG2a antibody the entire C{sub H}1 domain is deleted whereas the hinge region remains intact. Small-angle X-ray scattering data were collected for the short-chain IgG2a antibody and compared with those for the switch variant IgG1, IgG2a, and IgG2b antibodies with the normal heavy chain. It has been concluded that deletion of the C{sub H}1 domain results in a large structural change and the short-chain IgG2a antibody possesses an elongated molecular shape with a much smaller hinge angle as compared with the normal IgG2a antibody that is a Y-shaped molecule.

The Structure of Urease Activation Complexes Examined by Flexibility Analysis, Mutagenesis, and Small-angle X-ray Scattering Approaches

International Nuclear Information System (INIS)

Quiroz, Soledad; Sukuru, Sai Chetan K.; Hausinger, Robert P.; Kuhn, Leslie A.; Heller, William T

2008-01-01

Conformational changes of Klebsiella aerogenes urease apoprotein (UreABC) 3 induced upon binding of the UreD and UreF accessory proteins were examined by a combination of flexibility analysis, mutagenesis, and small-angle X-ray scattering (SAXS). ProFlex analysis of urease provided evidence that the major domain of UreB can move in a hinge-like motion to account for prior chemical cross-linking results. Rigidification of the UreB hinge region, accomplished through a G11P mutation, reduced the extent of urease activation, in part by decreasing the nickel content of the mutant enzyme, and by sequestering a portion of the urease apoprotein in a novel activation complex that includes all of the accessory proteins. SAXS analyses of urease, (UreABC-UreD) 3 , and (UreABC-UreDF) 3 confirm that UreD and UreF bind near UreB at the periphery of the (UreAC) 3 structure. This study supports an activation model in which a domain-shifted UreB conformation in (UreABC-UreDF) 3 allows CO 2 and nickel ions to gain access to the nascent active site

A gas microstrip wide angle X-ray detector for application in synchrotron radiation experiments

CERN Document Server

Bateman, J E; Derbyshire, G E; Duxbury, D M; Lipp, J; Mir, J A; Simmons, J E; Spill, E J; Stephenson, R; Dobson, B R; Farrow, R C; Helsby, W I; Mutikainen, R; Suni, I

2002-01-01

The Gas Microstrip Detector has counting rate capabilities several orders of magnitude higher than conventional wire proportional counters while providing the same (or better) energy resolution for X-rays. In addition the geometric flexibility provided by the lithographic process combined with the self-supporting properties of the substrate offers many exciting possibilities for X-ray detectors, particularly for the demanding experiments carried out on Synchrotron Radiation Sources. Using experience obtained in designing detectors for Particle Physics we have developed a detector for Wide Angle X-ray Scattering studies. The detector has a fan geometry which makes possible a gas detector with high detection efficiency, sub-millimetre spatial resolution and good energy resolution over a wide range of X-ray energy. The detector is described together with results of experiments carried out at the Daresbury Laboratory Synchrotron Radiation Source.

Small-angle X-ray scattering tensor tomography: model of the three-dimensional reciprocal-space map, reconstruction algorithm and angular sampling requirements.

Science.gov (United States)

Liebi, Marianne; Georgiadis, Marios; Kohlbrecher, Joachim; Holler, Mirko; Raabe, Jörg; Usov, Ivan; Menzel, Andreas; Schneider, Philipp; Bunk, Oliver; Guizar-Sicairos, Manuel

2018-01-01

Small-angle X-ray scattering tensor tomography, which allows reconstruction of the local three-dimensional reciprocal-space map within a three-dimensional sample as introduced by Liebi et al. [Nature (2015), 527, 349-352], is described in more detail with regard to the mathematical framework and the optimization algorithm. For the case of trabecular bone samples from vertebrae it is shown that the model of the three-dimensional reciprocal-space map using spherical harmonics can adequately describe the measured data. The method enables the determination of nanostructure orientation and degree of orientation as demonstrated previously in a single momentum transfer q range. This article presents a reconstruction of the complete reciprocal-space map for the case of bone over extended ranges of q. In addition, it is shown that uniform angular sampling and advanced regularization strategies help to reduce the amount of data required.

The oblique view for spondylolysis in the growing period. X-ray projection angle to spondylolytic lumbar vertebra based on CT scanning

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Yoshimitsu; Minato, Izumi; Nagano, Junji; Inoue, Yoshiya; Takahashi, Yuji; Saito, Hidehiko [Seirei Hamamatsu General Hospital, Shizuoka (Japan)

1996-02-01

In this study, CT images of 239 vertebrae from 227 patients with spondylolysis in the growing period were obtained to analyze x-ray oblique separation images based on the relationship between x-ray incidence angle and CT. The age of the subjects ranged from 5 to 23 years (average 14.8 years), of which 224 patients were 18 years or lower. The CT images obtained were classified into four according to our classification, i.e., Type Ia, 112 vertebrae; Type Ib, 175; Type II, 66; Type III, 67. All patients underwent plain x-ray from 4 directions including 45deg. The angle of separation line and posterior margin of the vertebral body was obtained and the average angle of all slices was determined as separation angle. As a result, depiction level of separation line was better in 30deg oblique images than 45deg oblique images in Ia, Ib, and III groups. It is thus desirable to take the relationship between incidence angle of x-ray, separation angle, and CT classification into consideration. (S.Y.).

The oblique view for spondylolysis in the growing period. X-ray projection angle to spondylolytic lumbar vertebra based on CT scanning

International Nuclear Information System (INIS)

Kobayashi, Yoshimitsu; Minato, Izumi; Nagano, Junji; Inoue, Yoshiya; Takahashi, Yuji; Saito, Hidehiko

1996-01-01

In this study, CT images of 239 vertebrae from 227 patients with spondylolysis in the growing period were obtained to analyze x-ray oblique separation images based on the relationship between x-ray incidence angle and CT. The age of the subjects ranged from 5 to 23 years (average 14.8 years), of which 224 patients were 18 years or lower. The CT images obtained were classified into four according to our classification, i.e., Type Ia, 112 vertebrae; Type Ib, 175; Type II, 66; Type III, 67. All patients underwent plain x-ray from 4 directions including 45deg. The angle of separation line and posterior margin of the vertebral body was obtained and the average angle of all slices was determined as separation angle. As a result, depiction level of separation line was better in 30deg oblique images than 45deg oblique images in Ia, Ib, and III groups. It is thus desirable to take the relationship between incidence angle of x-ray, separation angle, and CT classification into consideration. (S.Y.)

JMFA2—a graphically interactive Java program that fits microfibril angle X-ray diffraction data

Science.gov (United States)

Steve P. Verrill; David E. Kretschmann; Victoria L. Herian

2006-01-01

X-ray diffraction techniques have the potential to decrease the time required to determine microfibril angles dramatically. In this paper, we discuss the latest version of a curve-fitting toll that permits us to reduce the time required to evaluate MFA X-ray diffraction patterns. Further, because this tool reflects the underlying physics more accurately than existing...

Wavelet-based feature extraction applied to small-angle x-ray scattering patterns from breast tissue: a tool for differentiating between tissue types

International Nuclear Information System (INIS)

Falzon, G; Pearson, S; Murison, R; Hall, C; Siu, K; Evans, A; Rogers, K; Lewis, R

2006-01-01

This paper reports on the application of wavelet decomposition to small-angle x-ray scattering (SAXS) patterns from human breast tissue produced by a synchrotron source. The pixel intensities of SAXS patterns of normal, benign and malignant tissue types were transformed into wavelet coefficients. Statistical analysis found significant differences between the wavelet coefficients describing the patterns produced by different tissue types. These differences were then correlated with position in the image and have been linked to the supra-molecular structural changes that occur in breast tissue in the presence of disease. Specifically, results indicate that there are significant differences between healthy and diseased tissues in the wavelet coefficients that describe the peaks produced by the axial d-spacing of collagen. These differences suggest that a useful classification tool could be based upon the spectral information within the axial peaks

X-ray holography. Atoms in three dimensions

International Nuclear Information System (INIS)

Tegze, M.

2005-01-01

The principles of atomic resolution X-ray holography was elaborated in 1991. X-ray photons scatter thousand times less on atoms than electrons of the same wavelength. As a result, both free path and penetration depth are higher which giver information about the bulk material. X-ray holography is realized by irradiating the single crystal sample with radiation from external X-ray source. The incident radiation is ionizing the atoms of the sample to emit fluorescent radiation. The angle dependence of the fluorescent radiation results an image containing the hologram. The hologram itself is extremely small compared to the background that needs 10 10 capturing photons to recover image. Using Thomas Gog's method and synchrotron radiation the X-ray holography becomes more usable, but the method still needs refining both experimentally and theoretically. (TRA)

Performance verification of the Gravity and Extreme Magnetism Small explorer (GEMS) x-ray polarimeter

Science.gov (United States)

Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kaneko, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi; Marlowe, Hannah; Griffiths, Scott; Kaaret, Philip E.; Kenward, David; Khalid, Syed

2014-07-01

Polarimetry is a powerful tool for astrophysical observations that has yet to be exploited in the X-ray band. For satellite-borne and sounding rocket experiments, we have developed a photoelectric gas polarimeter to measure X-ray polarization in the 2-10 keV range utilizing a time projection chamber (TPC) and advanced micro-pattern gas electron multiplier (GEM) techniques. We carried out performance verification of a flight equivalent unit (1/4 model) which was planned to be launched on the NASA Gravity and Extreme Magnetism Small Explorer (GEMS) satellite. The test was performed at Brookhaven National Laboratory, National Synchrotron Light Source (NSLS) facility in April 2013. The polarimeter was irradiated with linearly-polarized monochromatic X-rays between 2.3 and 10.0 keV and scanned with a collimated beam at 5 different detector positions. After a systematic investigation of the detector response, a modulation factor >=35% above 4 keV was obtained with the expected polarization angle. At energies below 4 keV where the photoelectron track becomes short, diffusion in the region between the GEM and readout strips leaves an asymmetric photoelectron image. A correction method retrieves an expected modulation angle, and the expected modulation factor, ~20% at 2.7 keV. Folding the measured values of modulation through an instrument model gives sensitivity, parameterized by minimum detectable polarization (MDP), nearly identical to that assumed at the preliminary design review (PDR).

Performance Verification of the Gravity and Extreme Magnetism Small Explorer GEMS X-Ray Polarimeter

Science.gov (United States)

Enoto, Teruaki; Black, J. Kevin; Kitaguchi, Takao; Hayato, Asami; Hill, Joanne E.; Jahoda, Keith; Tamagawa, Toru; Kanako, Kenta; Takeuchi, Yoko; Yoshikawa, Akifumi;

Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

Science.gov (United States)

Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

2015-03-10

A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

Evidence of relationships between texture and structure in smectite systems by small angle synchrotron X ray scattering

International Nuclear Information System (INIS)

Pons, Charles-Henri

1980-01-01

Phyllosilicates are major constituents of soils, and their partially swelled or dispersed states play an important role in sedimentary geology, in soil science, in biochemistry, and also in various technological applications (drilling sludge, oil synthesis catalysts). Properties of these systems are also in direct relationship with problems such as fixation of pollutants by soil (pesticides, heavy metals, radioactive materials, so on). After having recalled works performed during the past forty years on water-smectite dispersions to define prevailing factors of processes of formation of colloidal states, the author presents the different phyllosilicates which have been studied, and recalls the determining factors of inflation and dispersion mechanisms. Then, he recalls methods of interpretation of X diffraction diagrams and of small angle scattering. He reports the detailed study of the inflation mechanism in the case of montmorillonite- Na, and discusses results obtained with other phyllosilicates or with other cations than sodium. In appendix, the author reports the study of bi-ionic (Na-Ca) montmorillonite suspensions prepared by two different methods. He also discusses the method of interpretation of neutron small angle scattering which had been used on similar systems, and shows why this method leads to questionable conclusions

Low Mass X-ray Binary 4U1705-44 Exiting an Extended High X-ray State

Science.gov (United States)

Phillipson, Rebecca; Boyd, Patricia T.; Smale, Alan P.

2017-09-01

The neutron-star low-mass X-ray binary 4U1705-44, which exhibited high amplitude long-term X-ray variability on the order of hundreds of days during the 16-year continuous monitoring by the RXTE ASM (1995-2012), entered an anomalously long high state in July 2012 as observed by MAXI (2009-present).

Comprehension of direct extraction of hydrophilic antioxidants using vegetable oils by polar paradox theory and small angle X-ray scattering analysis.

Science.gov (United States)

Li, Ying; Fabiano-Tixier, Anne Sylvie; Ruiz, Karine; Rossignol Castera, Anne; Bauduin, Pierre; Diat, Olivier; Chemat, Farid

2015-04-15

Since the polar paradox theory rationalised the fact that polar antioxidants are more effective in nonpolar media, extractions of phenolic compounds in vegetable oils were inspired and achieved in this study for obtaining oils enriched in phenolic compounds. Moreover, the influence of surfactants on the extractability of phenolic compounds was experimentally studied first, followed by the small angle X-ray scattering analysis for the oil structural observation before and after extraction so as to better understand the dissolving mechanism underpinning the extraction. The results showed a significant difference on the extraction yield of phenolic compounds among oils, which was mainly dependent on their composition instead of the unsaturation of fatty acids. Appropriate surfactant additions could significantly improve extraction yield for refined sunflower oils, which 1% w/w addition of glyceryl oleate was determined as the optimal. Besides, 5% w/w addition of lecithin performed the best in oil enrichments compared with mono- and di-glycerides. Copyright © 2014 Elsevier Ltd. All rights reserved.

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}

A library for X-ray-matter interaction cross sections for X-ray fluorescence applications

Energy Technology Data Exchange (ETDEWEB)

Brunetti, A. [Istituto di Matematica e Fisica, Universita di Sassari, via Vienna 2, 07100 Sassari (Italy) and INFN, Sezione di Cagliari (Italy)]. E-mail: brunetti@uniss.it; Sanchez del Rio, M. [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble Cedex (France); Golosio, B. [INFN, Sezione di Cagliari (Italy); European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble Cedex (France); Simionovici, A. [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble Cedex (France); Laboratoire de Sciences de la Terre, Ecole Normale Superieure, Lyon, F-69364 (France); Somogyi, A. [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble Cedex (France)

2004-10-08

Quantitative estimate of elemental composition by spectroscopic and imaging techniques using X-ray fluorescence requires the availability of accurate data of X-ray interaction with matter. Although a wide number of computer codes and data sets are reported in literature, none of them is presented in the form of freely available library functions which can be easily included in software applications for X-ray fluorescence. This work presents a compilation of data sets from different published works and an xraylib interface in the form of callable functions. Although the target applications are on X-ray fluorescence, cross sections of interactions like photoionization, coherent scattering and Compton scattering, as well as form factors and anomalous scattering functions, are also available.

Small-angle x-ray scattering study of kinetics of spinodal decomposition in N-isopropylacrylamide gels

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

X-ray fluorescence imaging with polycapillary X-ray optics

International Nuclear Information System (INIS)

Yonehara, Tasuku; Yamaguchi, Makoto; Tsuji, Kouichi

2010-01-01

X-ray fluorescence spectrometry imaging is a powerful tool to provide information about the chemical composition and elemental distribution of a specimen. X-ray fluorescence spectrometry images were conventionally obtained by using a μ-X-ray fluorescence spectrometry spectrometer, which requires scanning a sample. Faster X-ray fluorescence spectrometry imaging would be achieved by eliminating the process of sample scanning. Thus, we developed an X-ray fluorescence spectrometry imaging instrument without sample scanning by using polycapillary X-ray optics, which had energy filter characteristics caused by the energy dependence of the total reflection phenomenon. In the present paper, we show that two independent straight polycapillary X-ray optics could be used as an energy filter of X-rays for X-ray fluorescence. Only low energy X-rays were detected when the angle between the two optical axes was increased slightly. Energy-selective X-ray fluorescence spectrometry images with projection mode were taken by using an X-ray CCD camera equipped with two polycapillary optics. It was shown that Fe Kα (6.40 keV) and Cu Kα (8.04 keV) could be discriminated for Fe and Cu foils.

Poisson's ratio of collagen fibrils measured by small angle X-ray scattering of strained bovine pericardium

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.

Review of the fundamental theories behind small angle X-ray scattering, molecular dynamics simulations, and relevant integrated application

Directory of Open Access Journals (Sweden)

Lauren Boldon

2015-02-01

Full Text Available In this paper, the fundamental concepts and equations necessary for performing small angle X-ray scattering (SAXS experiments, molecular dynamics (MD simulations, and MD-SAXS analyses were reviewed. Furthermore, several key biological and non-biological applications for SAXS, MD, and MD-SAXS are presented in this review; however, this article does not cover all possible applications. SAXS is an experimental technique used for the analysis of a wide variety of biological and non-biological structures. SAXS utilizes spherical averaging to produce one- or two-dimensional intensity profiles, from which structural data may be extracted. MD simulation is a computer simulation technique that is used to model complex biological and non-biological systems at the atomic level. MD simulations apply classical Newtonian mechanics’ equations of motion to perform force calculations and to predict the theoretical physical properties of the system. This review presents several applications that highlight the ability of both SAXS and MD to study protein folding and function in addition to non-biological applications, such as the study of mechanical, electrical, and structural properties of non-biological nanoparticles. Lastly, the potential benefits of combining SAXS and MD simulations for the study of both biological and non-biological systems are demonstrated through the presentation of several examples that combine the two techniques.

Review of the fundamental theories behind small angle X-ray scattering, molecular dynamics simulations, and relevant integrated application.

Science.gov (United States)

Boldon, Lauren; Laliberte, Fallon; Liu, Li

2015-01-01

In this paper, the fundamental concepts and equations necessary for performing small angle X-ray scattering (SAXS) experiments, molecular dynamics (MD) simulations, and MD-SAXS analyses were reviewed. Furthermore, several key biological and non-biological applications for SAXS, MD, and MD-SAXS are presented in this review; however, this article does not cover all possible applications. SAXS is an experimental technique used for the analysis of a wide variety of biological and non-biological structures. SAXS utilizes spherical averaging to produce one- or two-dimensional intensity profiles, from which structural data may be extracted. MD simulation is a computer simulation technique that is used to model complex biological and non-biological systems at the atomic level. MD simulations apply classical Newtonian mechanics' equations of motion to perform force calculations and to predict the theoretical physical properties of the system. This review presents several applications that highlight the ability of both SAXS and MD to study protein folding and function in addition to non-biological applications, such as the study of mechanical, electrical, and structural properties of non-biological nanoparticles. Lastly, the potential benefits of combining SAXS and MD simulations for the study of both biological and non-biological systems are demonstrated through the presentation of several examples that combine the two techniques.

A filter based analyzer for studies of X-ray Raman scattering

CERN Document Server

Seidler, G T

2001-01-01

Non-resonant X-ray Raman scattering (XRS) with hard X-rays holds the potential for measuring local structure and local electronic properties around low-Z atoms in environments where traditional soft X-ray techniques are inapplicable. However, the small cross-section for XRS requires that experiments must simultaneously achieve high detection efficiency, large collection solid angles, and good energy resolution. We report here that a simple X-ray analyzer consisting of an absorber and a point-focusing spatial filter can be used to study some X-ray Raman near-edge features. This apparatus has greater than 10% detection efficiency, has an energy resolution of 8 eV, and can be readily extended to collection angles of more than 1 sr. We present preliminary measurements of the XRS from the nitrogen 1 s shell in pyrolitic boron nitride.

Coherent hard x-ray focusing optics and applications

Energy Technology Data Exchange (ETDEWEB)

Yun, W.B.; Viccaro, P.J.; Chrzas, J.; Lai, B.

1991-01-01

Coherent hard x-ray beams with a flux exceeding 10{sup 9} photons/second with a bandwidth of 0.1% will be provided by the undulator at the third generation synchrotron radiation sources such as APS, ESRF, and Spring-8. The availability of such high flux coherent x-ray beams offers excellent opportunities for extending the coherence-based techniques developed in the visible and soft x-ray part of the electromagnetic spectrum to the hard x-rays. These x-ray techniques (e.g., diffraction limited microfocusing, holography, interferometry, phase contrast imaging and signal enhancement), may offer substantial advantages over non-coherence-based x-ray techniques currently used. For example, the signal enhancement technique may be used to enhance an anomalous x-ray or magnetic x-ray scattering signal by several orders of magnitude. Coherent x-rays can be focused to a very small (diffraction-limited) spot size, thus allowing high spatial resolution microprobes to be constructed. The paper will discuss the feasibility of the extension of some coherence-based techniques to the hard x-ray range and the significant progress that has been made in the development of diffraction-limited focusing optics. Specific experimental results for a transmission Fresnel phase zone plate that can focus 8.2 keV x-rays to a spot size of about 2 microns will be briefly discussed. The comparison of measured focusing efficiency of the zone plate with that calculated will be made. Some specific applications of zone plates as coherent x-ray optics will be discussed. 17 refs., 4 figs.

Anomalous x-ray attenuation coefficients around the absorption edges using Mn Ksub(α) and Cu Ksub(α) x-rays

International Nuclear Information System (INIS)

Kerur, B.R.; Thontadarya, S.R.; Hanumaiah, B.

1994-01-01

The x-ray attenuation coefficients for three elements and for eight compounds are determined, adopting the method developed by employing a proportional counter, with a view to study the effect of fine structure on the mass attenuation coefficient values using Mn K α and Cu K α x-rays derived from K x-ray emitters, 55 Fe and 65 Zn radioactive sources, by a differential absorption technique. It is experimentally established that a small difference in energy between K α1 and K α2 (11 eV in the case of Mn K α and 24 eV in the case of the Cu K α x-ray) is inconsequential by comparing the measured and theoretical values of μ/ρ for standard elements, aluminium, copper and tantalum. The effect of fine structure on μ/ρ values is studied using the compounds containing one element with its absorption edge close to the incident photon energy. Results obtained in the present investigation show the nonvalidity of the mixture rule above the edge and also below the edge, ranging from about 600 eV below the edge to about 1500 eV about the edge. The contribution of resonance Raman scattering to the attenuation coefficient and indications to the presence of pre-edge structure similar to EXAFS are discussed. (author)

Note: Application of a pixel-array area detector to simultaneous single crystal x-ray diffraction and x-ray absorption spectroscopy measurements

International Nuclear Information System (INIS)

Sun, Cheng-Jun; Brewe, Dale L.; Heald, Steve M.; Zhang, Bangmin; Chen, Jing-Sheng; Chow, G. M.; Venkatesan, T.

2014-01-01

X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr 0.67 Sr 0.33 MnO 3 film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam

X-ray irradiation induced reduction and nanoclustering of lead in borosilicate glass

NARCIS (Netherlands)

Stanley, H.B.; Banerjee, D.; Breemen, van L.C.A.; Ciston, J.; Liebscher, C.H.; Martis, V.; Merino, D.H.; Longo, A.; Pattison, P.; Peters, G.W.M.; Portale, G.; Sen, Sabyasachi; Bras, W.

2014-01-01

We have studied the formation of nanoparticles in lead sulfide (PbS)-doped borosilicate glass subjected to a two-step nucleation and growth heat treatment using in situ small-angle X-ray scattering (SAXS). The microstructure produced was subsequently characterized using X-ray powder diffraction

A high pressure study of calmodulin-ligand interactions using small-angle X-ray and elastic incoherent neutron scattering.

Science.gov (United States)

Cinar, Süleyman; Al-Ayoubi, Samy; Sternemann, Christian; Peters, Judith; Winter, Roland; Czeslik, Claus

2018-01-31

Calmodulin (CaM) is a Ca 2+ sensor and mediates Ca 2+ signaling through binding of numerous target ligands. The binding of ligands by Ca 2+ -saturated CaM (holo-CaM) is governed by attractive hydrophobic and electrostatic interactions that are weakened under high pressure in aqueous solutions. Moreover, the potential formation of void volumes upon ligand binding creates a further source of pressure sensitivity. Hence, high pressure is a suitable thermodynamic variable to probe protein-ligand interactions. In this study, we compare the binding of two different ligands to holo-CaM as a function of pressure by using X-ray and neutron scattering techniques. The two ligands are the farnesylated hypervariable region (HVR) of the K-Ras4B protein, which is a natural binding partner of holo-CaM, and the antagonist trifluoperazine (TFP), which is known to inhibit holo-CaM activity. From small-angle X-ray scattering experiments performed up to 3000 bar, we observe a pressure-induced partial unfolding of the free holo-CaM in the absence of ligands, where the two lobes of the dumbbell-shaped protein are slightly swelled. In contrast, upon binding TFP, holo-CaM forms a closed globular conformation, which is pressure stable at least up to 3000 bar. The HVR of K-Ras4B shows a different binding behavior, and the data suggest the dissociation of the holo-CaM/HVR complex under high pressure, probably due to a less dense protein contact of the HVR as compared to TFP. The elastic incoherent neutron scattering experiments corroborate these findings. Below 2000 bar, pressure induces enhanced atomic fluctuations in both holo-CaM/ligand complexes, but those of the holo-CaM/HVR complex seem to be larger. Thus, the inhibition of holo-CaM by TFP is supported by a low-volume ligand binding, albeit this is not associated with a rigidification of the complex structure on the sub-ns Å-scale.

Healing X-ray scattering images

Directory of Open Access Journals (Sweden)

Jiliang Liu

2017-07-01

Full Text Available X-ray scattering images contain numerous gaps and defects arising from detector limitations and experimental configuration. We present a method to heal X-ray scattering images, filling gaps in the data and removing defects in a physically meaningful manner. Unlike generic inpainting methods, this method is closely tuned to the expected structure of reciprocal-space data. In particular, we exploit statistical tests and symmetry analysis to identify the structure of an image; we then copy, average and interpolate measured data into gaps in a way that respects the identified structure and symmetry. Importantly, the underlying analysis methods provide useful characterization of structures present in the image, including the identification of diffuse versus sharp features, anisotropy and symmetry. The presented method leverages known characteristics of reciprocal space, enabling physically reasonable reconstruction even with large image gaps. The method will correspondingly fail for images that violate these underlying assumptions. The method assumes point symmetry and is thus applicable to small-angle X-ray scattering (SAXS data, but only to a subset of wide-angle data. Our method succeeds in filling gaps and healing defects in experimental images, including extending data beyond the original detector borders.

Exploring structural variability in X-ray crystallographic models using protein local optimization by torsion-angle sampling

International Nuclear Information System (INIS)

Knight, Jennifer L.; Zhou, Zhiyong; Gallicchio, Emilio; Himmel, Daniel M.; Friesner, Richard A.; Arnold, Eddy; Levy, Ronald M.

2008-01-01

Torsion-angle sampling, as implemented in the Protein Local Optimization Program (PLOP), is used to generate multiple structurally variable single-conformer models which are in good agreement with X-ray data. An ensemble-refinement approach to differentiate between positional uncertainty and conformational heterogeneity is proposed. Modeling structural variability is critical for understanding protein function and for modeling reliable targets for in silico docking experiments. Because of the time-intensive nature of manual X-ray crystallographic refinement, automated refinement methods that thoroughly explore conformational space are essential for the systematic construction of structurally variable models. Using five proteins spanning resolutions of 1.0–2.8 Å, it is demonstrated how torsion-angle sampling of backbone and side-chain libraries with filtering against both the chemical energy, using a modern effective potential, and the electron density, coupled with minimization of a reciprocal-space X-ray target function, can generate multiple structurally variable models which fit the X-ray data well. Torsion-angle sampling as implemented in the Protein Local Optimization Program (PLOP) has been used in this work. Models with the lowest R free values are obtained when electrostatic and implicit solvation terms are included in the effective potential. HIV-1 protease, calmodulin and SUMO-conjugating enzyme illustrate how variability in the ensemble of structures captures structural variability that is observed across multiple crystal structures and is linked to functional flexibility at hinge regions and binding interfaces. An ensemble-refinement procedure is proposed to differentiate between variability that is a consequence of physical conformational heterogeneity and that which reflects uncertainty in the atomic coordinates

The BESSY X-ray microfocus beamline project

International Nuclear Information System (INIS)

Erko, A.; Schaefers, F.; Firsov, A.; Peatman, W.B.; Eberhardt, W.; Signorato, R.

2004-01-01

The design and construction of a beamline dedicated to X-ray absorption spectroscopy, X-ray fluorescence analysis, X-ray diffraction and X-ray small-angle scattering measurements with micron and submicron spatial resolution in the photon energy range of 1.9-30 keV are reported here. The main feature of the beamline is a combination of all these methods in one experimental station. The source will be a BESSY 7-T wavelength shifter, which is already in operation. Such a wavelength shifter with its continuous spectrum is an optimum source for these experiments. Glass capillaries and the combination of a linear Bragg-Fresnel lens and bimorph mirror were chosen as the special optical components in the beamline. This beamline will open for BESSY users the possibility to perform experiments on the same sample applying a microfocused X-ray beam in combination with advanced experimental methods

Ordering parameters of three-dimensional ordered quantum-dot lattices determined by anomalous x-ray diffraction

International Nuclear Information System (INIS)

Lechner, R.T.; Springholz, G.; Stangl, J.; Raab, A.; Bauer, G.; Schuelli, T.U.; Holy, V.; Metzger, T.H.

2004-01-01

Three dimensional (3D) quantum dot structures can be obtained, e.g., by the growth of self-assembled quantum dot multilayers in which vertically and laterally ordered dot superstructures are formed as a result of the elastic interlayer dot interactions between the dots. This not only results in a significant narrowing of the size distribution, but different 3D interlayer correlations can be obtained by changes in the spacer thickness, as has been demonstrated for the PbSe/PbEuTe quantum dot material system. Apart from microscopic techniques, x-ray diffraction is a very powerful tool to characterize the ordering in such 3D assembled quantum dot structures. However, the analysis of the diffraction spectra is usually complicated by the weak scattering contrast between the self-assembled quantum dots and the surrounding matrix material. In the present work, we therefore employ anomalous x-ray diffraction with synchrotron radiation to drastically enhance the chemical contrast in such multilayers by tuning the wavelength close to an inner shell absorption resonance. This technique is applied to determine the ordering of differently stacked self-assembled PbSe quantum dot lattices fabricated by molecular beam epitaxy. In this case, the x-ray wavelength is tuned to the Pb M-shell at 5.1 Aato enhance the scattering contrast between the PbSe dots and the matrix material in comparison to the results obtained using conventional x-ray wavelengths around 1.5 Aa. As a result, it is shown that the lateral ordering is significantly better for 3D trigonal PbSe dot superlattices as compared to those with 3D hexagonal dot arrangement. (author)

X-ray interferometers

International Nuclear Information System (INIS)

Franks, A.

1980-01-01

An improved type of amplitude-division x-ray interferometer is described. The wavelength at which the interferometer can operate is variable, allowing the instrument to be used to measure x-ray wavelength, and the angle of inclination is variable for sample investigation. (U.K.)

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

Topological investigation of electronic silicon nanoparticulate aggregates using ultra-small-angle X-ray scattering

CSIR Research Space (South Africa)

Jonah, EO

2012-10-01

Full Text Available The network topology of two types of silicon nanoparticles, produced by high energy milling and pyrolysis of silane, in layers deposited from inks on permeable and impermeable substrates has been quantitatively characterized using ultra-small-angle...

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.

EFFECTS OF X-RAY BEAM ANGLE AND GEOMETRIC DISTORTION ON WIDTH OF EQUINE THORACOLUMBAR INTERSPINOUS SPACES USING RADIOGRAPHY AND COMPUTED TOMOGRAPHY

DEFF Research Database (Denmark)

Djernaes, Julie D.; Nielsen, Jon V.; Berg, Lise C.

2017-01-01

The widths of spaces between the thoracolumbar processi spinosi (interspinous spaces) are frequently assessed using radiography in sports horses; however effects of varying X-ray beam angles and geometric distortion have not been previously described. The aim of this prospective, observational...... study was to determine whether X-ray beam angle has an effect on apparent widths of interspinous spaces. Thoracolumbar spine specimens were collected from six equine cadavers and left-right lateral radiographs and sagittal and dorsal reconstructed computed tomographic (CT) images were acquired...... measurements. Effect of geometric distortion was evaluated by comparing the interspinous space in radiographs with sagittal and dorsal reconstructed CT images. A total of 49 interspinous spaces were sampled, yielding 274 measurements. X-ray beam angle significantly affected measured width of interspinous...

Colliding Stellar Winds Structure and X-ray Emission

Science.gov (United States)

Pittard, J. M.; Dawson, B.

2018-04-01

We investigate the structure and X-ray emission from the colliding stellar winds in massive star binaries. We find that the opening angle of the contact discontinuity (CD) is overestimated by several formulae in the literature at very small values of the wind momentum ratio, η. We find also that the shocks in the primary (dominant) and secondary winds flare by ≈20° compared to the CD, and that the entire secondary wind is shocked when η ≲ 0.02. Analytical expressions for the opening angles of the shocks, and the fraction of each wind that is shocked, are provided. We find that the X-ray luminosity Lx∝η, and that the spectrum softens slightly as η decreases.

Precise small-angle X-ray scattering evaluation of the pore structures in track-etched membranes: Comparison with other convenient evaluation methods

Energy Technology Data Exchange (ETDEWEB)

Miyazaki, Tsukasa, E-mail: t_miyazaki@cross.or.jp [Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society, 162-1, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1106 (Japan); Takenaka, Mikihito [Department of Polymer Chemistry, Gradual School of Engineering, Kyoto University, Kyotodaigaku-katsura, Kyoto 615-8510 (Japan)

2017-03-01

Poly(ethylene terephthalate) (PET)-based track-etched membranes (TMs) with pore sizes ranging from few nanometers to approximately 1 μm are used in various applications in the biological field, and their pore structures are determined by small-angle X-ray scattering (SAXS). These TMs with the nanometer-sized cylindrical pores aligned parallel to the film thickness direction are produced by chemical etching of the track in the PET films irradiated by heavy ions with the sodium hydroxide aqueous solution. It is well known that SAXS allows us to precisely and statistically estimate the pore size and the pore size distribution in the TMs by using the form factor of a cylinder with the extremely long pore length relative to the pore diameter. The results obtained were compared with those estimated with scanning electron microscopy and gas permeability measurements. The result showed that the gas permeability measurement is convenient to evaluate the pore size of TMs within a wide length scale, and the SEM observation is also suited to estimate the pore size, although SEM observation is usually limited above approximately 30 nm.

Near edge x-ray spectroscopy theory

International Nuclear Information System (INIS)

1994-01-01

We propose to develop a quantitative theory of x-ray spectroscopies in the near edge region, within about 100 eV of threshold. These spectroscopies include XAFS (X-ray absorption fine structure), photoelectron diffraction (PD), and diffraction anomalous fine structure (DAFS), all of which are important tools for structural studies using synchrotron radiation x-ray sources. Of primary importance in these studies are many-body effects, such as the photoelectron self-energy, and inelastic losses. A better understanding of these quantities is needed to obtain theories without adjustable parameters. We propose both analytical and numerical calculations, the latter based on our x-ray spectroscopy codes FEFF

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

RXTE Monitoring of the Anomalous X-ray Pulsar 1E 1048.1-5937: Long-Term Variability and the 2007 March Event

Science.gov (United States)

Dib, Rim; Kaspi, Victoria M.; Gavriil, Fotis P.

2009-01-01

After three years of no unusual activity, Anomalous X-ray Pulsar 1E 1048.1-5937 reactivated in 2007 March. We report on the detection of a large glitch (deltav/v = 1.63(2) x 10(exp -5)) on 2007 March 26 (MJD 54185.9), contemporaneous with the onset of a pulsed-flux flare, the third flare observed from this source in 10 years of monitoring with the Rossi X-ray Timing Explorer. Additionally, we report on a detailed study of the evolution of the timing properties, the pulsed flux, and the pulse profile of this source as measured by RXTE from 1996 July to 2008 January. In our timing study, we attempted phase coherent timing of all available observations. We show that in 2001, a timing anomaly of uncertain nature occurred near the rise of the first pulsed flux flare; we show that a likely glitch (deltav/v = 2.91(9) x 10(exp -6)) occurred in 2002, near the rise of the second flare, and we present a detailed description of the variations in the spin-down. In our pulsed flux study, we compare the decays of the three flares and discuss changes in the hardness ratio. In our pulse profile study, we show that the profile exhibited large variations near the peak of the first two flares, and several small short-term profile variations during the most recent flare. Finally, we report on the discovery of a small burst 27 days after the peak of the last flare, the fourth burst discovered from this source. We discuss the relationships between the observed properties in the framework of the magnetar model.

Pionic 4f-3d X-rays from 208Pb and 209Bi

International Nuclear Information System (INIS)

Olin, A.; Forsman, J.W.; MacDonald, J.A.; Marshall, G.M.; Numao, T.; Poffenberger, P.R.; Van Esbroek, P.; Kunselman, A.R.; Olaniyi, B.H.

1985-01-01

The X-ray energies and widths of the pionic 4f-3d and 5g-4f transitions have been measured in 208 Pb and 209 Bi. The 3d widths obtained are in reasonable agreement with theory, and do not support the anomalously small values previously reported. (orig.)

(an)isotropy of the X-ray sky

International Nuclear Information System (INIS)

Shafer, R.A.; Fabian, A.C.

1983-01-01

An assessment is made of the extent to which the study of the isotropy of the X-ray sky has contributed to the present understanding of the structure of the universe at moderate redshifts. It is, of course, the anisotropic character of the sky flux that is valuable in this context. Although it is not currently possible to undertake measurements with the precision and small solid angles that are typically achieved in the microwave range, the comparatively crude limits from the X-ray fluctuations place limits on the largest scale structure of the universe. After indicating the nature of measurements made, with the HEAO 1 A-2 experiment, of the X-ray sky and its anisotropies, it is shown how these place limits on the origin of the X-ray sky and on any large scale structure of the universe. 40 references

Estimation of degree of polymerization of poly-acrylonitrile-grafted carbon nanotubes using Guinier plot of small angle x-ray scattering.

Science.gov (United States)

Cho, Hyunjung; Jin, Kyeong Sik; Lee, Jaegeun; Lee, Kun-Hong

2018-07-06

Small angle x-ray scattering (SAXS) was used to estimate the degree of polymerization of polymer-grafted carbon nanotubes (CNTs) synthesized using a 'grafting from' method. This analysis characterizes the grafted polymer chains without cleaving them from CNTs, and provides reliable data that can complement conventional methods such as thermogravimetric analysis or transmittance electron microscopy. Acrylonitrile was polymerized from the surface of the CNTs by using redox initiation to produce poly-acrylonitrile-grafted CNTs (PAN-CNTs). Polymerization time and the initiation rate were varied to control the degree of polymerization. Radius of gyration (R g ) of PAN-CNTs was determined using the Guinier plot obtained from SAXS solution analysis. The results showed consistent values according to the polymerization condition, up to a maximum R g  = 125.70 Å whereas that of pristine CNTs was 99.23 Å. The dispersibility of PAN-CNTs in N,N-dimethylformamide was tested using ultraviolet-visible-near infrared spectroscopy and was confirmed to increase as the degree of polymerization increased. This analysis will be helpful to estimate the degree of polymerization of any polymer-grafted CNTs synthesized using the 'grafting from' method and to fabricate polymer/CNT composite materials.

Structural analysis of the yeast exosome Rrp6p–Rrp47p complex by small-angle X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Dedic, Emil; Seweryn, Paulina; Jonstrup, Anette Thyssen; Flygaard, Rasmus Koch [Centre for mRNP Biogenesis and Metabolism, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Department of Molecular Biology and Genetics, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Fedosova, Natalya U. [Department of Biomedicine, Ole Worms Allé 6, Aarhus University, DK-8000 Aarhus C (Denmark); Hoffmann, Søren Vrønning [Institute for Storage Ring Facilities (ISA), Department of Physics and Astronomy, Ny Munkegade 120, Aarhus University, DK-8000 Aarhus C (Denmark); Boesen, Thomas [Centre for Membrane Pumps in Cells and Disease – PUMPKIN, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Department of Molecular Biology and Genetics, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Brodersen, Ditlev Egeskov, E-mail: deb@mb.au.dk [Centre for mRNP Biogenesis and Metabolism, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark); Department of Molecular Biology and Genetics, Gustav Wieds Vej 10c, Aarhus University, DK-8000 Aarhus C (Denmark)

2014-07-18

Highlights: • We show that S. cerevisiae Rrp6p and Rrp47p stabilise each other in vitro. • We determine molecular envelopes of the Rrp6p–Rrp47p complex by SAXS. • Rrp47p binds at the top of the Rrp6p exonuclease domain. • Rrp47p modulates the activity of Rrp6p on a variety of RNA substrates. • Rrp47p does not affect RNA affinity by Rrp6p. - Abstract: The RNase D-type 3′–5′ exonuclease Rrp6p from Saccharomyces cerevisiae is a nuclear-specific cofactor of the RNA exosome and associates in vivo with Rrp47p (Lrp1p). Here, we show using biochemistry and small-angle X-ray scattering (SAXS) that Rrp6p and Rrp47p associate into a stable, heterodimeric complex with an elongated shape consistent with binding of Rrp47p to the nuclease domain and opposite of the HRDC domain of Rrp6p. Rrp47p reduces the exonucleolytic activity of Rrp6p on both single-stranded and structured RNA substrates without significantly altering the affinity towards RNA or the ability of Rrp6p to degrade RNA secondary structure.

Structural analysis of the yeast exosome Rrp6p–Rrp47p complex by small-angle X-ray scattering

International Nuclear Information System (INIS)

Dedic, Emil; Seweryn, Paulina; Jonstrup, Anette Thyssen; Flygaard, Rasmus Koch; Fedosova, Natalya U.; Hoffmann, Søren Vrønning; Boesen, Thomas; Brodersen, Ditlev Egeskov

2014-01-01

Highlights: • We show that S. cerevisiae Rrp6p and Rrp47p stabilise each other in vitro. • We determine molecular envelopes of the Rrp6p–Rrp47p complex by SAXS. • Rrp47p binds at the top of the Rrp6p exonuclease domain. • Rrp47p modulates the activity of Rrp6p on a variety of RNA substrates. • Rrp47p does not affect RNA affinity by Rrp6p. - Abstract: The RNase D-type 3′–5′ exonuclease Rrp6p from Saccharomyces cerevisiae is a nuclear-specific cofactor of the RNA exosome and associates in vivo with Rrp47p (Lrp1p). Here, we show using biochemistry and small-angle X-ray scattering (SAXS) that Rrp6p and Rrp47p associate into a stable, heterodimeric complex with an elongated shape consistent with binding of Rrp47p to the nuclease domain and opposite of the HRDC domain of Rrp6p. Rrp47p reduces the exonucleolytic activity of Rrp6p on both single-stranded and structured RNA substrates without significantly altering the affinity towards RNA or the ability of Rrp6p to degrade RNA secondary structure

Development of small scale soft x-ray lasers: Aspects of data interpretation

International Nuclear Information System (INIS)

Skinner, C.H.; Kim, D.; Voorhees, D.; Suckewer, S.

1990-02-01

The widespread application of soft x-ray laser technology is contingent on the development of small scale soft x-ray lasers that do not require large laser facilities. Progress in the development of soft x-ray lasers pumped by a Nd laser of energy 6-12J is reported below. Some aspects of data interpretation and gain measurements in such systems are discussed. 11 refs., 11 figs

Polarization reversal and ferroelectric domain structure observed in electroded cesium dihydrogen phosphate crystals using an X-ray anomalous dispersion effect

International Nuclear Information System (INIS)

Ozaki, Toru; Amau, Toshirou; Kawata, Hiroshi; Mizuno, Kaoru; Mori, Koichi.

1997-01-01

We have carried out an X-ray intensity measurement and X-ray topography on electroded b plates of ferroelectric cesium dihydrogen phosphate, CsH 2 PO 4 (CDP), using a synchrotron radiation with a wavelength of 2.482 A above the Cs L 3 -absorption edge. We have found that integrated intensities I(150) and I(1-bar5-bar0) show an anomalously large breakdown of Friedel's law, I(150)/I(1-bar5-bar0)=10.4 at 125 K, and display a ferroelectric hysteresis loop. The hysteresis loop determines that spontaneous polarization is antiparallel to the b axes set in both ferroelectric crystal structures related by inversions. The (150) diffraction topography shows that a single domain turns into a lamellar domain structure without fractal aspects after short-circuiting the b plate. The atomic displacement associated with polarization reversal is shown in a crystal structure model of 180deg domains observed in the X-ray topography. (author)

X-ray diffraction

International Nuclear Information System (INIS)

Vries, J.L. de.

1976-01-01

The seventh edition of Philips' Review of literature on X-ray diffraction begins with a list of conference proceedings on the subject, organised by the Philips' organisation at regular intervals in various European countries. This is followed by a list of bulletins. The bibliography is divided according to the equipment (cameras, diffractometers, monochromators) and its applications. The applications are subdivided into sections for high/low temperature and pressure, effects due to the equipment, small angle scattering and a part for stress, texture and phase analyses of metals and quantitative analysis of minerals

The influence of the oblique incident X-ray that affected the image quality of the X-ray CCD sensor

International Nuclear Information System (INIS)

Suzuki, Yosuke; Matsumoto, Nobue; Morita, Hiroshi; Ohkawa, Hiromitsu

1998-01-01

The influence of the oblique incident X-ray that affected the image quality of the X-ray CCD sensor was examined and its correction was investigated. CDR was adopted in this study and evaluated image quality, by measuring MTF. The oblique projection was clinically permissible to about an oblique incident angle of 40 degrees although it exerts an influence on the magnifying power and density. The estimation of the oblique entrance direction and oblique incident angle was possible, by developing an oblique incident correction marker. When an oblique incident angle of θ degrees was measured, a correction is possible, by compressing the image cos (θ) times perpendicular to the rotational axis of CCD sensor. There was small decline of MTF, in the image where a correction for the influence of oblique incidence was made. By observation of the digital subtracted picture of the image after correction of oblique projection and that of normal, the resemblance in the two images indicated that this correction method was reasonable. (author)

EVOLUTION OF INTERMEDIATE-MASS X-RAY BINARIES DRIVEN BY THE MAGNETIC BRAKING OF AP/BP STARS. I. ULTRACOMPACT X-RAY BINARIES

Energy Technology Data Exchange (ETDEWEB)

Chen, Wen-Cong [School of Physics and Electrical Information, Shangqiu Normal University, Shangqiu 476000 (China); Podsiadlowski, Philipp, E-mail: chenwc@pku.edu.cn [Department of Physics, University of Oxford, Oxford OX1 3RH (United Kingdom)

2016-10-20

It is generally believed that ultracompact X-ray binaries (UCXBs) evolved from binaries consisting of a neutron star accreting from a low-mass white dwarf (WD) or helium star where mass transfer is driven by gravitational radiation. However, the standard WD evolutionary channel cannot produce the relatively long-period (40–60 minutes) UCXBs with a high time-averaged mass-transfer rate. In this work, we explore an alternative evolutionary route toward UCXBs, where the companions evolve from intermediate-mass Ap/Bp stars with an anomalously strong magnetic field (100–10,000 G). Including the magnetic braking caused by the coupling between the magnetic field and an irradiation-driven wind induced by the X-ray flux from the accreting component, we show that intermediate-mass X-ray binaries (IMXBs) can evolve into UCXBs. Using the MESA code, we have calculated evolutionary sequences for a large number of IMXBs. The simulated results indicate that, for a small wind-driving efficiency f = 10{sup −5}, the anomalous magnetic braking can drive IMXBs to an ultra-short period of 11 minutes. Comparing our simulated results with the observed parameters of 15 identified UCXBs, the anomalous magnetic braking evolutionary channel can account for the formation of seven and eight sources with f = 10{sup −3}, and 10{sup −5}, respectively. In particular, a relatively large value of f can fit three of the long-period, persistent sources with a high mass-transfer rate. Though the proportion of Ap/Bp stars in intermediate-mass stars is only 5%, the lifetime of the UCXB phase is ≳2 Gyr, producing a relatively high number of observable systems, making this an alternative evolutionary channel for the formation of UCXBs.

Analyser-based x-ray imaging for biomedical research

International Nuclear Information System (INIS)

Suortti, Pekka; Keyriläinen, Jani; Thomlinson, William

2013-01-01

Analyser-based imaging (ABI) is one of the several phase-contrast x-ray imaging techniques being pursued at synchrotron radiation facilities. With advancements in compact source technology, there is a possibility that ABI will become a clinical imaging modality. This paper presents the history of ABI as it has developed from its laboratory source to synchrotron imaging. The fundamental physics of phase-contrast imaging is presented both in a general sense and specifically for ABI. The technology is dependent on the use of perfect crystal monochromator optics. The theory of the x-ray optics is developed and presented in a way that will allow optimization of the imaging for specific biomedical systems. The advancement of analytical algorithms to produce separate images of the sample absorption, refraction angle map and small-angle x-ray scattering is detailed. Several detailed applications to biomedical imaging are presented to illustrate the broad range of systems and body sites studied preclinically to date: breast, cartilage and bone, soft tissue and organs. Ultimately, the application of ABI in clinical imaging will depend partly on the availability of compact sources with sufficient x-ray intensity comparable with that of the current synchrotron environment. (paper)

X-ray phase imaging using a X-ray tube with a small focal spot. Improvement of image quality in mammography

International Nuclear Information System (INIS)

Honda, Chika; Ohara, Hiromu; Ishisaka, Akira; Shimada, Fumio

2002-01-01

Phase contrast X-ray imaging has been studied intensively using X-rays from synchrotron radiation and micro-focus X-ray tubes. However, these studies have revealed the difficulty of this technique's application to practical medical imaging. We have created a phase contrast imaging technique using a molybdenum X-ray tube with a small focal spot size for mammography. We identified the radiographic conditions in phase contrast magnification mammography with a screen-film system, where edge effect due to phase contrast overcomes geometrical unsharpness caused by the 0.1 mm-focal spot of a molybdenum X-ray tube. The edge enhancement due to phase imaging was observed in an image of a plastic tube, and then geometrical configuration of the X-ray tube, the object and the screen-film system was determined for phase imaging of mammography. In order to investigate a potential for medical application of this method, we conducted evaluation of the images of the American Collage of Radiology (ACR) 156 mammography phantom. We obtained higher scores for phase imaging using high speed screen-film systems without any increase of X-ray dose than the score for contract imaging using a standard speed screen-film system. (author)

Assessment of firing conditions in old fired-clay bricks: The contribution of X-ray powder diffraction with the Rietveld method and small angle neutron scattering

Energy Technology Data Exchange (ETDEWEB)

Viani, Alberto, E-mail: viani@itam.cas.cz [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic); Sotiriadis, Konstantinos [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic); Len, Adél [Wigner Research Centre for Physics HAS, Konkoly-Thege 29-33, 1121 Budapest (Hungary); Šašek, Petr; Ševčík, Radek [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic)

2016-06-15

Full characterization of fired-clay bricks is crucial for the improvement of process variables in manufacturing and, in case of old bricks, for restoration/replacement purposes. To this aim, five bricks produced in a plant in Czech Republic in the past have been investigated with a combination of analytical techniques in order to derive information on the firing process. An additional old brick from another brickyard was also used to study the influence of different raw materials on sample microstructure. The potential of X-ray diffraction with the Rietveld method and small angle neutron scattering technique has been exploited to describe the phase transformations taking place during firing and characterize the brick microstructure. Unit-cell parameter of spinel and amount of hematite are proposed as indicators of the maximum firing temperature, although for the latter, limited to bricks produced from the same raw material. The fractal quality of the surface area of pores obtained from small angle neutron scattering is also suggested as a method to distinguish between bricks produced from different raw clays. - Highlights: • Rietveld method helps in describing microstructure and physical properties of bricks. • XRPD derived cell parameter of spinel is proposed as an indicator of firing temperature. • SANS effectively describes brick micro and nanostructure, including closed porosity. • Fractal quality of pore surface is proposed as ‘fingerprint’ of brick manufacturing.

A summary of the low angle x-ray atomic scattering factors which have been measured by the critical voltage effect in High Energy Electron Diffraction (HEED)

International Nuclear Information System (INIS)

Fox, A.G.; Fisher, R.M.

1987-08-01

A tabulated summary of all the accurate (/approximately/0.1%) low-angle x-ray atomic scattering (form) factors which have been determined by the systematic critical voltage technique in HEED is presented. For low atomic number elements (Z/approx lt/40) the low angle form factors can be significantly different to best free atom values, and so the best band structure calculated and/or x-ray measured form factors consistent with the critical voltage measurements are also indicated. At intermediate atomic numbers Z≅40→50 only the very low-angle form factors appear to be different to the best free atom values, and even then only by a small amount. For heavy elements (Z/approx lt/70) the best free atom form factors appear to agree very closely with the critical voltage measured values and so, in this case, critical voltage measurements give very accurate measurements of Debye-Waller factors. 48 refs

Low-angle polarized neutron and X-ray scattering from magnetic nanolayers and nanostructures

CERN Document Server

Paul, Amitesh

2017-01-01

This research monograph presents the latest results related to the characterization of low dimensional systems. Low-angle polarized neutron scattering and X-ray scattering at grazing incidence are used as the two main techniques to explore various physical phenomena of these systems. Special focus is put on systems like thin film transition metal and rare-earth layers, oxide heterostructures, hybrid systems, self-assembled nanostructures and self-diffusion.  Readers will gain in-depth knowledge about the usage of specular scattering and off-specular scattering techniques. Investigation of in-plane and out-of-plane structures and magnetism with vector magnetometric information is illustrated comprehensively. The book caters to a wide audience working in the field of nano-dimensional magnetic systems and the neutron and X-ray reflectometry community in particular.

X-ray characterization of solid small molecule organic materials

Science.gov (United States)

Billinge, Simon; Shankland, Kenneth; Shankland, Norman; Florence, Alastair

2014-06-10

The present invention provides, inter alia, methods of characterizing a small molecule organic material, e.g., a drug or a drug product. This method includes subjecting the solid small molecule organic material to x-ray total scattering analysis at a short wavelength, collecting data generated thereby, and mathematically transforming the data to provide a refined set of data.

X-ray microscopy using grazing-incidence reflections optics

International Nuclear Information System (INIS)

Price, R.H.

1983-01-01

The role of Kirkpatrick-Baez microscopes as the workhorse of the x-ray imaging devices is discussed. This role is being extended with the development of a 22X magnification Kirkpatrick-Baez x-ray microscope with multilayer x-ray mirrors. These mirrors can operate at large angles, high x-ray energies, and have a narrow, well defined x-ray energy bandpass. This will make them useful for numerous experiments. However, where a large solid angle is needed, the Woelter microscope will still be necessary and the technology needed to build them will be useful for many other types of x-ray optics

A high-resolution multiwire area detector for X-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Faruqi, A R; Andrews, H [Medical Research Council, Cambridge (UK). Lab. of Molecular Biology

1989-11-10

A high-resolution multiwire area detector has been developed for recording X-ray scattering from biological specimens. The detector is 100x100 mm{sup 2} and, under the present operating conditions, has a spatial resolution of about 250 {mu}m in both directions. The detector is set up on a double-mirror focusing camera on a rotating anode X-ray generator and has been used in a number of small-angle experiments, two of which are described in this paper. (orig.).

ACCURATE MODELING OF X-RAY EXTINCTION BY INTERSTELLAR GRAINS

International Nuclear Information System (INIS)

Hoffman, John; Draine, B. T.

2016-01-01

Interstellar abundance determinations from fits to X-ray absorption edges often rely on the incorrect assumption that scattering is insignificant and can be ignored. We show instead that scattering contributes significantly to the attenuation of X-rays for realistic dust grain size distributions and substantially modifies the spectrum near absorption edges of elements present in grains. The dust attenuation modules used in major X-ray spectral fitting programs do not take this into account. We show that the consequences of neglecting scattering on the determination of interstellar elemental abundances are modest; however, scattering (along with uncertainties in the grain size distribution) must be taken into account when near-edge extinction fine structure is used to infer dust mineralogy. We advertise the benefits and accuracy of anomalous diffraction theory for both X-ray halo analysis and near edge absorption studies. We present an open source Fortran suite, General Geometry Anomalous Diffraction Theory (GGADT), that calculates X-ray absorption, scattering, and differential scattering cross sections for grains of arbitrary geometry and composition

ACCURATE MODELING OF X-RAY EXTINCTION BY INTERSTELLAR GRAINS

Energy Technology Data Exchange (ETDEWEB)

Hoffman, John; Draine, B. T., E-mail: jah5@astro.princeton.edu, E-mail: draine@astro.princeton.edu [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544-1001 (United States)

2016-02-01

Interstellar abundance determinations from fits to X-ray absorption edges often rely on the incorrect assumption that scattering is insignificant and can be ignored. We show instead that scattering contributes significantly to the attenuation of X-rays for realistic dust grain size distributions and substantially modifies the spectrum near absorption edges of elements present in grains. The dust attenuation modules used in major X-ray spectral fitting programs do not take this into account. We show that the consequences of neglecting scattering on the determination of interstellar elemental abundances are modest; however, scattering (along with uncertainties in the grain size distribution) must be taken into account when near-edge extinction fine structure is used to infer dust mineralogy. We advertise the benefits and accuracy of anomalous diffraction theory for both X-ray halo analysis and near edge absorption studies. We present an open source Fortran suite, General Geometry Anomalous Diffraction Theory (GGADT), that calculates X-ray absorption, scattering, and differential scattering cross sections for grains of arbitrary geometry and composition.

Location of cholesterol in liposomes by using small-angle X-ray scattering (SAXS) data and the generalized indirect Fourier transformation (GIFT) method.

Science.gov (United States)

Aburai, Kenichi; Ogura, Taku; Hyodo, Ryo; Sakai, Hideki; Abe, Masahiko; Glatter, Otto

2013-01-01

We investigated the location of cholesterol (Chol) in liposomes and its interaction with phospholipids using small-angle x-ray scattering (SAXS) data and applying the generalized indirect Fourier transformation (GIFT) method. The GIFT method has been applied to lamellar liquid crystal systems and it gives quantitative data on bilayer thickness, electron density profile, and membrane flexibility (Caillé parameter). When the GIFT method is applied to the SAXS data of dipalmitoylphosphatidylcholine (DPPC) alone (Chol [-]) or a DPPC/Chol = 7/3 mixed system (Chol [+], molar ratio), change in the bilayer thickness was insignificant in both systems. However, the electron density for the Chol (+) system was higher than that for the Chol (-) system at the location of hydrophilic groups of phospholipids, and whereas Caillé parameter value increased with temperature for the Chol (-) system, no significant change with temperature was observed in the Caillé parameter for the Chol (+) system. These results indicated that Chol is located in the vicinity of the hydrophilic group of the phospholipids and constricts the packing of the acyl chain of phospholipids in the bilayer.

Aggregation of bovine serum albumin upon cleavage of its disulfide bonds, studied by the time-resolved small-angle X-ray scattering technique with synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Ueki, Tatzuo; Inoko, Yoji; Hiragi, Yuzuru; Kataoka, Mikio; Amemiya, Yoshiyuki; Izumi, Yoshinobu; Tagawa, Hiroyuki; Muroga, Yoshio

1985-11-01

A rapid mixing system of the stopped-flow type, used with small-angle X-ray scattering equipment using synchrotron radiation, is described. The process of aggregation of bovine serum albumin was traced with a time interval of 50s, initiated upon cleavage of its disulfide bonds by reduction with dithiothreitol. The results indicate that a 218-fold molar excess of dithiothreitol over the number of moles of disulfide bonds in bovine serum albumin is sufficient to initiate the reaction immediately after mixing, which reaches equilibrium in about 15 min. On the other hand, half this amount is not sufficient to initiate the reaction, so that the reaction is delayed by about 150s. Such a single-shot time-resolved experiment showed that experiments with a time interval of 100 ms are possible with repeated multi-shot runs. 26 refs.; 8 figs.

Core–Shell Structure and Aggregation Number of Micelles Composed of Amphiphilic Block Copolymers and Amphiphilic Heterografted Polymer Brushes Determined by Small-Angle X-ray Scattering

Energy Technology Data Exchange (ETDEWEB)

Szymusiak, Magdalena; Kalkowski, Joseph; Luo, Hanying; Donovan, Alexander J.; Zhang, Pin; Liu, Chang; Shang, Weifeng; Irving, Thomas; Herrera-Alonso, Margarita; Liu, Ying (JHU); (IIT); (UIC)

2017-08-31

A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core–shell micelles composed of linear diblock copolymers poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL), poly(ethylene oxide)-b-poly(lactic acid) (PEG-b-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-g-PEG/PLA) were characterized by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core–shell size, and aggregation number. The structural information at this quasi-equilibrium state can also be used as a reference when studying the kinetics of polymer micellization.

Core–Shell Structure and Aggregation Number of Micelles Composed of Amphiphilic Block Copolymers and Amphiphilic Heterografted Polymer Brushes Determined by Small-Angle X-ray Scattering

Energy Technology Data Exchange (ETDEWEB)

Szymusiak, Magdalena [Department; Kalkowski, Joseph [Department; Luo, Hanying [Department; Donovan, Alexander J. [Department; Zhang, Pin [Department; Liu, Chang [Department; Shang, Weifeng [Department; Irving, Thomas [Department; Herrera-Alonso, Margarita [Department; Liu, Ying [Department; Department

2017-08-16

A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core–shell micelles composed of linear diblock copolymers poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL), poly(ethylene oxide)-b-poly(lactic acid) (PEG-b-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-g-PEG/PLA) were characterized by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core–shell size, and aggregation number. The structural information at this quasi-equilibrium state can also be used as a reference when studying the kinetics of polymer micellization.

Aggregation of bovine serum albumin upon cleavage of its disulfide bonds, studied by the time-resolved small-angle X-ray scattering technique with synchrotron radiation

International Nuclear Information System (INIS)

Ueki, Tatzuo; Inoko, Yoji; Izumi, Yoshinobu; Tagawa, Hiroyuki; Muroga, Yoshio

1985-01-01

A rapid mixing system of the stopped-flow type, used with small-angle X-ray scattering equipment using synchrotron radiation, is described. The process of aggregation of bovine serum albumin was traced with a time interval of 50 s, initiated upon cleavage of its disulfide bonds by reduction with dithiothreitol. The results indicate that a 218-fold molar excess of dithiothreitol over the number of moles of disulfide bonds in bovine serum albumin is sufficient to initiate the reaction immediately after mixing, which reaches equilibrium in about 15 min. On the other hand, half this amount is not sufficient to initiate the reaction, so that the reaction is delayed by about 150 s. Such a single-shot time-resolved experiment showed that experiments with a time interval of 100 ms are possible with repeated multi-shot runs. (Auth.)

X-ray optics for scanning fluorescence microscopy and other applications

International Nuclear Information System (INIS)

Ryon, R.W.; Warburton, W.K.

1992-05-01

Scanning x-ray fluorescence microscopy is analogous to scanning electron microscopy. Maps of chemical element distribution are produced by scanning with a very small x-ray beam. Goal is to perform such scanning microscopy with resolution in the range of <1 to 10 μm, using standard laboratory x-ray tubes. We are investigating mirror optics in the Kirkpatrick-Baez (K-B) configuration. K-B optics uses two curved mirrors mounted orthogonally along the optical axis. The first mirror provides vertical focus, the second mirror provides horizontal focus. We have used two types of mirrors: synthetic multilayers and crystals. Multilayer mirrors are used with lower energy radiation such as Cu Kα. At higher energies such as Ag Kα, silicon wafers are used in order to increase the incidence angles and thereby the photon collection efficiency. In order to increase the surface area of multilayers which reflects x-rays at the Bragg angle, we have designed mirrors with the spacing between layers graded along the optic axis in order to compensate for the changing angle of incidence. Likewise, to achieve a large reflecting surface with silicon, the wafers are placed on a specially designed lever arm which is bent into a log spiral by applying force at one end. In this way, the same diffracting angle is maintained over the entire surface of the wafer, providing a large solid angle for photon collection

Tertiary and quaternary structural differences between two genetic variants of bovine casein by small-angle X-ray scattering

International Nuclear Information System (INIS)

Pessen, H.; Kumosinski, T.F.; Farrell, H.M. Jr.; Brumberger, H.

1991-01-01

The casein complexes of bovine milk consist of four major protein fractions, alpha s1, alpha s2, beta, and kappa. Colloidal particles of casein (termed micelles) contain inorganic calcium and phosphate; they are very roughly spherical with an average radius of 650 A. Removal of Ca2+ leads to the formation of smaller protein aggregates with an average radius of 94 A. Two genetic variants, A and B, of the predominant fraction, alpha s1-casein, result in milks with markedly different physical properties, such as solubility and heat stability. To investigate the molecular basis for these differences, small-angle X-ray scattering was performed on the respective colloidal micelles and submicelles. Scattering curves for submicelles of both variants showed multiple Gaussian character; data for the B variant were previously interpreted in terms of two concentric regions of different electron density, i.e., a compact core and a relatively loose shell. For the submicelle of A, there was a third Gaussian, reflecting a negative contribution due to interparticle interference. Molecular parameters for submicelles of both A and B are in agreement with hydrodynamic data in the literature. Data for the micelles, for which scattering yields cross-sectional information, were fitted by a sum of three Gaussians for both variants; for these, the corresponding two lower radii of gyration represent the two concentric regions of the submicelles, while the third reflects the average packing of submicelles within the micellar cross section. Most of the molecular parameters obtained showed small but consistent differences between A and B, but for submicelles within the micelle several differences were particularly notable: A has a greater molecular weight for the compact region of the constituent submicelle (82,000 vs 60,000) and a much greater submicellar packing number

Arrangement for X-ray shield

International Nuclear Information System (INIS)

1980-01-01

X-ray screen unit consisting of a light transmissive carrier onto which scintillation material is deposited, which is able to generate light under the influence of incident X-ray irradiation, characterised in that the X-ray screen comprises a number of sectors, wherein the surface with respect to the incident X-radiation is maintained at an acute angle. (G.C.)

Ultrafast x-ray scattering on nanoparticle dynamics

International Nuclear Information System (INIS)

Plech, A; Ibrahimkutty, S; Issenmann, D; Kotaidis, V; Siems, A

2013-01-01

Pulsed X-ray scattering is used for the determination of structural dynamics of laser-irradiated gold particles. By combining several scattering methods such as powder scattering, small angle scattering and diffuse wide angle scattering it is possible to reconstruct the kinetics of structure evolution on several lengths scales and derive complementary information on the particles and their local environment. A generic structural phase diagram for the reaction as function of delay time after laser excitation and laser fluence can be constructed.

Note: Comparison of grazing incidence small angle x-ray scattering of a titania sponge structure at the beamlines BW4 (DORIS III) and P03 (PETRA III)

International Nuclear Information System (INIS)

Rawolle, M.; Körstgens, V.; Ruderer, M. A.; Metwalli, E.; Guo, S.; Müller-Buschbaum, P.; Herzog, G.; Benecke, G.; Schwartzkopf, M.; Buffet, A.; Perlich, J.; Roth, S. V.

2012-01-01

Grazing incidence small angle x-ray scattering (GISAXS) is a powerful technique for morphology investigation of nanostructured thin films. GISAXS measurements at the newly installed P03 beamline at the storage ring PETRA III in Hamburg, Germany, are compared to the GISAXS data from the beamline BW4 at the storage ring DORIS III, which had been used extensively for GISAXS investigations in the past. As an example, a titania thin film sponge structure is investigated. Compared to BW4, at beamline P03 the resolution of larger structures is slightly improved and a higher incident flux leads to a factor of 750 in scattered intensity. Therefore, the acquisition time in GISAXS geometry is reduced significantly at beamline P03.

Performance of the PRAXyS X-ray polarimeter

Energy Technology Data Exchange (ETDEWEB)

Iwakiri, W.B., E-mail: wataru.iwakiri@riken.jp [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Black, J.K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Rock Creek Scientific, 1400 East-West Hwy, Silver Spring, MD 20910 (United States); Cole, R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Enoto, T. [The Hakubi Center for Advanced Research, Kyoto University, Kyoto 606-8302 (Japan); Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Hayato, A. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hill, J.E.; Jahoda, K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kaaret, P. [University of Iowa, Iowa City, IA 52242 (United States); Kitaguchi, T. [Department of Physical Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kubota, M. [Department of Physics, Tokyo University of Science, 3-1 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Marlowe, H.; McCurdy, R. [University of Iowa, Iowa City, IA 52242 (United States); Takeuchi, Y. [Department of Physics, Tokyo University of Science, 3-1 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tamagawa, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Tokyo University of Science, 3-1 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. (Japan)

2016-12-01

The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will enable exploration of the universe through X-ray polarimetry in the 2–10 keV energy band. We carried out performance tests of the polarimeter at the Brookhaven National Laboratory, National Synchrotron Light Source (BNL-NSLS) and at NASA's Goddard Space Flight Center. The polarimeter was tested with linearly polarized, monochromatic X-rays at 11 different energies between 2.5 and 8.0 keV. At maximum sensitivity, the measured modulation factors at 2.7, 4.5 and 8.0 keV are 27%, 43% and 59%, respectively and the measured angle of polarization is consistent with the expected value at all energies. Measurements with a broadband, unpolarized X-ray source placed a limit of less than 1% on false polarization in the PRAXyS polarimeter.

Performance of the PRAXyS X-ray polarimeter

Science.gov (United States)

Iwakiri, W. B.; Black, J. K.; Cole, R.; Enoto, T.; Hayato, A.; Hill, J. E.; Jahoda, K.; Kaaret, P.; Kitaguchi, T.; Kubota, M.; Marlowe, H.; McCurdy, R.; Takeuchi, Y.; Tamagawa, T.

2016-12-01

The performance of the Time Projection Chamber (TPC) polarimeter for the Polarimeter for Relativistic Astrophysical X-ray Sources (PRAXyS) Small Explorer was evaluated using polarized and unpolarized X-ray sources. The PRAXyS mission will enable exploration of the universe through X-ray polarimetry in the 2-10 keV energy band. We carried out performance tests of the polarimeter at the Brookhaven National Laboratory, National Synchrotron Light Source (BNL-NSLS) and at NASA's Goddard Space Flight Center. The polarimeter was tested with linearly polarized, monochromatic X-rays at 11 different energies between 2.5 and 8.0 keV. At maximum sensitivity, the measured modulation factors at 2.7, 4.5 and 8.0 keV are 27%, 43% and 59%, respectively and the measured angle of polarization is consistent with the expected value at all energies. Measurements with a broadband, unpolarized X-ray source placed a limit of less than 1% on false polarization in the PRAXyS polarimeter.

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

X-ray apparatus

International Nuclear Information System (INIS)

Bernstein, S.; Stagg, L.; Lambert, T.W.; Griswa, P.J.

1976-01-01

A patient support system for X-ray equipment in arteriographic studies of the heart is described in detail. The support system has been designed to overcome many of the practical problems encountered in using previous types of arteriographic X-ray equipment. The support system is capable of horizontal movement and, by a series of shafts attached to the main support system, the X-ray source and image intensifier or detector may be rotated through the same angle. The system is highly flexible and details are given of several possible operational modes. (U.K.)

Characterization of oxidized tannins: comparison of depolymerization methods, asymmetric flow field-flow fractionation and small-angle X-ray scattering.

Science.gov (United States)

Vernhet, Aude; Dubascoux, Stéphane; Cabane, Bernard; Fulcrand, Hélène; Dubreucq, Eric; Poncet-Legrand, Céline

2011-09-01

Condensed tannins are a major class of plant polyphenols. They play an important part in the colour and taste of foods and beverages. Due to their chemical reactivity, tannins are not stable once extracted from plants. A number of chemical reactions can take place, leading to structural changes of the native structures to give so-called derived tannins and pigments. This paper compares results obtained on native and oxidized tannins with different techniques: depolymerization followed by high-performance liquid chromatography analysis, small-angle X-ray scattering (SAXS) and asymmetric flow field-flow fractionation (AF4). Upon oxidation, new macromolecules were formed. Thioglycolysis experiments showed no evidence of molecular weight increase, but thioglycolysis yields drastically decreased. When oxidation was performed at high concentration (e.g., 10 g L(-1)), the weight average degree of polymerization determined from SAXS increased, whereas it remained stable when oxidation was done at low concentration (0.1 g L(-1)), indicating that the reaction was intramolecular, yet the conformations were different. Differences in terms of solubility were observed; ethanol being a better solvent than water. We also separated soluble and non-water-soluble species of a much oxidized fraction. Thioglycolysis showed no big differences between the two fractions, whereas SAXS and AF4 showed that insoluble macromolecules have a weight average molecular weight ten times higher than the soluble ones.

An optimised set-up for total reflection particle induced X-ray emission

International Nuclear Information System (INIS)

Kan, J.A. van; Vis, R.D.

1997-01-01

MeV proton beams at small angles of incidence (0-35 mrad) are used to analyse trace elements on flat surfaces such as Si wafers or quartz substrates. In these experiments, the particle induced X-ray emission (PIXE) signal is used in a new optimized set-up. This set-up is constructed in such a way that the X-ray detector can reach very large solid angles, larger than 1 sr. Use of these large detector solid angles, combined with the reduction of bremsstrahlung background, affords limits of detection (LOD) of the order of 10 10 at cm -2 using total reflection particle induced X-ray emission (TPIXE). The LODs from earlier TPIXE measurements in a non-optimized set-up are used to estimate LODs in the new TPIXE set-up. Si wafers with low surface concentrations of V, Ni, Cu and Ag are used as standards to calibrate the LODs found with this set-up. The metal concentrations are determined by total reflection X-ray fluorescence (TXRF). The TPIXE measurements are compared with TXRF measurements on the same wafers. (Author)

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive medical ...

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small dose ... limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is ...

Bone X-Ray (Radiography)

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

Abdomen X-Ray (Radiography)

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Abdomen Abdominal x-ray uses a very small ... of an abdominal x-ray? What is abdominal x-ray? An x-ray (radiograph) is a noninvasive medical ...

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

X-ray microscopy using grazing-incidence reflection optics

International Nuclear Information System (INIS)

Price, R.H.

1981-01-01

The Kirkpatrick-Baez microscopes are described along with their role as the workhorse of the x-ray imaging devices. This role is being extended with the development of a 22X magnification Kirkpatrick-Baez x-ray microscope with multilayer x-ray mirrors. These mirrors can operate at large angles, high x-ray energies, and have a narrow, well defined x-ray energy bandpass. This will make them useful for numerous experiments. However, where a large solid angle is needed, the Woelter microscope will still be necessary and the technology needed to build them will be useful for many other types of x-ray optics

Chest X-Ray

Medline Plus

Full Text Available ... about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed x-ray exams and use a very small dose of ... of the inside of the chest. A chest x-ray is used to evaluate the lungs, heart and ...

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.)

Angle-resolved X-ray fluorescence spectrometry using synchrotron radiation at ELSA

International Nuclear Information System (INIS)

Schmitt, W.; Rothe, J.; Hormes, J.; Gries, W.H.

1994-01-01

Measurements on the centroid depth of ion-implanted phosphorus-in-silicon specimen by the method of angle-resolved, self-ratio X-ray fluorescence spectrometry (AR/SR/XFS) have been carried out using 'white' synchrotron radiation (SR). The measurements were performed using a modified wavelength-dispersive fluorescence spectrometer. Problems due to the use of SR, like carbonaceous specimen contamination and sample heating were overcome by flooding the specimen chamber with helium and by pre-absorbing the non-exciting parts of the incident SR with suitable filters, respectively. The decaying primary intensity was monitored by measuring the compensation current of the photoelectrons emitted from a tungsten wire stretched across the primary beam. Results have been obtained for specimen with dose density levels of 10 16 cm -2 and 3x10 15 cm -2 . (orig.)

Energy dependence measurement of small-type optically stimulated luminescence (OSL) dosimeter by means of characteristic X-rays induced with general diagnostic X-ray equipment.

Science.gov (United States)

Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

2016-01-01

For X-ray inspections by way of general X-ray equipment, it is important to measure an entrance-skin dose. Recently, a small optically stimulated luminescence (OSL) dosimeter was made commercially available by Landauer, Inc. The dosimeter does not interfere with the medical images; therefore, it is expected to be a convenient detector for measuring personal exposure doses. In an actual clinical situation, it is assumed that X-rays of different energies will be detected by a dosimeter. For evaluation of the exposure dose measured by a dosimeter, it is necessary to know the energy dependence of the dosimeter. Our aim in this study was to measure the energy dependence of the OSL dosimeter experimentally in the diagnostic X-ray region. Metal samples weighing several grams were irradiated and, in this way, characteristic X-rays having energies ranging from 8 to 85 keV were generated. Using these mono-energetic X-rays, the dosimeter was irradiated. Simultaneously, the fluence of the X-rays was determined with a CdTe detector. The energy-dependent efficiency of the dosimeter was derived from the measured value of the dosimeter and the fluence. Moreover, the energy-dependent efficiency was calculated by Monte-Carlo simulation. The efficiency obtained in the experiment was in good agreement with that of the simulation. In conclusion, our proposed method, in which characteristic X-rays are used, is valuable for measurement of the energy dependence of a small OSL dosimeter in the diagnostic X-ray region.

Surface morphology of vacuum-evaporated pentacene film on Si substrate studied by in situ grazing-incidence small-angle X-ray scattering: I. The initial stage of formation of pentacene film

Science.gov (United States)

Hirosawa, Ichiro; Watanabe, Takeshi; Koganezawa, Tomoyuki; Kikuchi, Mamoru; Yoshimoto, Noriyuki

2018-03-01

The progress of the surface morphology of a growing sub-monolayered pentacene film on a Si substrate was studied by in situ grazing-incidence small angle X-ray scattering (GISAXS). The observed GISAXS profiles did not show sizes of pentacene islands but mainly protuberances on the boundaries around pentacene film. Scattering of X-ray by residual pits in the pentacene film was also detected in the GISAXS profiles of an almost fully covered film. The average radius of pentacene protuberances increased from 13 to 24 nm as the coverage increased to 0.83 monolayer, and the most frequent radius was almost constant at approximately 9 nm. This result suggests that the population of larger protuberances increase with increasing lengths of boundaries of the pentacene film. It can also be considered that the detected protuberances were crystallites of pentacene, since the average size of protuberances was nearly equal to crystallite sizes of pentacene films. The almost constant characteristic distance of 610 nm and amplitudes of pair correlation functions at low coverages suggest that the growth of pentacene films obeyed the diffusion-limited aggregation (DLA) model, as previously reported. It is also considered that the sites of islands show a triangular distribution for small variations of estimated correlation distances.

Cone Beam X-Ray Luminescence Tomography Imaging Based on KA-FEM Method for Small Animals.

Science.gov (United States)

Chen, Dongmei; Meng, Fanzhen; Zhao, Fengjun; Xu, Cao

2016-01-01

Cone beam X-ray luminescence tomography can realize fast X-ray luminescence tomography imaging with relatively low scanning time compared with narrow beam X-ray luminescence tomography. However, cone beam X-ray luminescence tomography suffers from an ill-posed reconstruction problem. First, the feasibility of experiments with different penetration and multispectra in small animal has been tested using nanophosphor material. Then, the hybrid reconstruction algorithm with KA-FEM method has been applied in cone beam X-ray luminescence tomography for small animals to overcome the ill-posed reconstruction problem, whose advantage and property have been demonstrated in fluorescence tomography imaging. The in vivo mouse experiment proved the feasibility of the proposed method.

Bone X-Ray (Radiography)

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Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

Structure factor of blends of solvent-free nanoparticle-organic hybrid materials: density-functional theory and small angle X-ray scattering.

Science.gov (United States)

Yu, Hsiu-Yu; Srivastava, Samanvaya; Archer, Lynden A; Koch, Donald L

2014-12-07

We investigate the static structure factor S(q) of solvent-free nanoparticle-organic hybrid materials consisting of silica nanocores and space-filling polyethylene glycol coronas using a density-functional theory and small angle X-ray scattering measurements. The theory considers a bidisperse suspension of hard spheres with different radii and tethered bead-spring oligomers with different grafting densities to approximate the polydispersity effects in experiments. The experimental systems studied include pure samples with different silica core volume fractions and the associated mean corona grafting densities, and blends with different mixing ratios of the pure samples, in order to introduce varying polydispersity of corona grafting density. Our scattering experiments and theory show that, compared to the hard-sphere suspension with the same core volume fraction, S(q) for pure samples exhibit both substantially smaller values at small q and stronger particle correlations corresponding to a larger effective hard core at large q, indicating that the tethered incompressible oligomers enforce a more uniform particle distribution, and the densely grafted brush gives rise to an additional exclusionary effect between the nanoparticles. According to the theory, polydispersity in the oligomer grafting density controls the deviation of S(q) from the monodisperse system at smaller q, and the interplay of the enhanced effective core size and the entropic attraction among the particles is responsible for complex variations in the particle correlations at larger q. The successful comparison between the predictions and the measurements for the blends further suggests that S(q) can be used to assess the uniformity of grafting density in polymer-grafted nanoparticle materials.

Transmission X-ray mirror

International Nuclear Information System (INIS)

Lairson, B.M.; Bilderback, D.H.

1982-01-01

Transmission X-ray mirrors have been made from 400 A to 10 000 A thick soap films and have been shown to have novel properties. Using grazing angles of incidence, low energy X-rays were reflected from the front surface while more energetic X-rays were transmitted through the mirror largely unattenuated. A wide bandpass monochromator was made from a silicon carbide mirror followed by a soap film transmission mirror and operated in the white beam at the cornell High Energy Synchrotron Source (CHESS). Bandpasses of ΔE/E=12% to 18% were achieved at 13 keV with peak efficiencies estimated to be between 55% and 75%, respectively. Several wide angle scattering photographs of stretched polyethylene and a phospholipid were obtained in 10 s using an 18% bandpass. (orig.)

Characterization of white poplar and eucalyptus after ionic liquid pretreatment as a function of biomass loading using X-ray diffraction and small angle neutron scattering

Energy Technology Data Exchange (ETDEWEB)

Yuan, Xueming [Beijing Univ. of Chemical Technology (China); Duan, Yonghao [Beijing Univ. of Chemical Technology (China); He, Lilin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Singh, Seema [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Simmons, Blake [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cheng, Gang [Beijing Univ. of Chemical Technology (China); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-02-08

A systematic study was done to understand interactions among biomass loading during ionic liquid (IL) pretreatment, biomass type and biomass structures. White poplar and eucalyptus samples were pretreated using 1-ethyl-3-methylimidazolium acetate (EmimOAc) at 110 °C for 3 h at biomass loadings of 5, 10, 15, 20 and 25 wt%. All of the samples were chemically characterized and tested for enzymatic hydrolysis. Physical structures including biomass crystallinity and porosity were measured by X-ray diffraction (XRD) and small angle neutron scattering (SANS), respectively. SANS detected pores of radii ranging from ~25 to 625 Å, enabling assessment of contributions of pores with different sizes to increased porosity after pretreatment. Contrasting dependences of sugar conversion on white poplar and eucalyptus as a function of biomass loading were observed and cellulose crystalline structure was found to play an important role.

Epoxy replication for Wolter x-ray microscope fabrication

International Nuclear Information System (INIS)

Priedhorsky, W.

1981-01-01

An epoxy replica of a test piece designed to simulate a Wolter x-ray microscope geometry showed no loss of x-ray reflectivity or resolution, compared to the original. The test piece was a diamond-turned cone with 1.5 0 half angle. A flat was fly-cut on one side, then super- and conventionally polished. The replica was separated at the 1.5 0 -draft angle, simulating a shallow angle Wolter microscope geometry. A test with 8.34 A x rays at 0.9 0 grazing angle showed a reflectivity of 67% for the replica flat surface, and 70% for the original. No spread of the reflected beam was observed with a 20-arc second wide test beam. This test verifies the epoxy replication technique for production of Wolter x-ray microscopes

Dental X-ray apparatus

International Nuclear Information System (INIS)

Weiss, M.E.

1980-01-01

Intra-oral dental X-ray apparatus for panoramic radiography is described in detail. It comprises a tubular target carrier supporting at its distal end a target with an inclined forward face. Image definition is improved by positioning in the path of the X-rays a window of X-ray transmitting ceramic material, e.g. 90% oxide of Be, or Al, 7% Si0 2 . The target carrier forms a probe which can be positioned in the patient's mouth. X-rays are directed forwardly and laterally of the target to an X-ray film positioned externally. The probe is provided with a detachable sleeve having V-form arms of X-ray opaque material which serve to depress the tongue out of the radiation path and also shield the roof of the mouth and other regions of the head from the X-ray pattern. A cylindrical lead shield defines the X-ray beam angle. (author)

Small-angle scattering study of mesoscopic structures in charged gel and their evolution on dehydration

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...

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.

In Situ Lipolysis and Synchrotron Small-Angle X-ray Scattering for the Direct Determination of the Precipitation and Solid-State Form of a Poorly Water-Soluble Drug During Digestion of a Lipid-Based Formulation

DEFF Research Database (Denmark)

Khan, Jamal; Hawley, Adrian; Rades, Thomas

2016-01-01

In situ lipolysis and synchrotron small-angle X-ray scattering (SAXS) were used to directly detect and elucidate the solid-state form of precipitated fenofibrate from the digestion of a model lipid-based formulation (LBF). This method was developed in light of recent findings that indicate variab...... on drugs, and experimental conditions, which are anticipated to produce altered solid-state forms upon the precipitation of drug (i.e., polymorphs, amorphous forms, and salts). © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci....

Ultrasmall-angle X-ray scattering analysis of photonic crystal structure

International Nuclear Information System (INIS)

Abramova, V. V.; Sinitskii, A. S.; Grigor'eva, N. A.; Grigor'ev, S. V.; Belov, D. V.; Petukhov, A. V.; Mistonov, A. A.; Vasil'eva, A. V.; Tret'yakov, Yu. D.

2009-01-01

The results of an ultrasmall-angle X-ray scattering study of iron(III) oxide inverse opal thin films are presented. The photonic crystals examined are shown to have fcc structure with amount of stacking faults varying among the samples. The method used in this study makes it possible to easily distinguish between samples with predominantly twinned fcc structure and nearly perfect fcc stacking. The difference observed between samples fabricated under identical conditions is attributed to random layer stacking in the self-assembled colloidal crystals used as templates for fabricating the inverse opals. The present method provides a versatile tool for analyzing photonic crystal structure in studies of inverse opals made of various materials, colloidal crystals, and three-dimensional photonic crystals of other types.

The Small-Angle Neutron Scattering Data Analysis of the Phospholipid Transport Nanosystem Structure

Science.gov (United States)

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).

Development of variable-magnification X-ray Bragg optics.

Science.gov (United States)

Hirano, Keiichi; Yamashita, Yoshiki; Takahashi, Yumiko; Sugiyama, Hiroshi

2015-07-01

A novel X-ray Bragg optics is proposed for variable-magnification of an X-ray beam. This X-ray Bragg optics is composed of two magnifiers in a crossed arrangement, and the magnification factor, M, is controlled through the azimuth angle of each magnifier. The basic properties of the X-ray optics such as the magnification factor, image transformation matrix and intrinsic acceptance angle are described based on the dynamical theory of X-ray diffraction. The feasibility of the variable-magnification X-ray Bragg optics was verified at the vertical-wiggler beamline BL-14B of the Photon Factory. For X-ray Bragg magnifiers, Si(220) crystals with an asymmetric angle of 14° were used. The magnification factor was calculated to be tunable between 0.1 and 10.0 at a wavelength of 0.112 nm. At various magnification factors (M ≥ 1.0), X-ray images of a nylon mesh were observed with an air-cooled X-ray CCD camera. Image deformation caused by the optics could be corrected by using a 2 × 2 transformation matrix and bilinear interpolation method. Not only absorption-contrast but also edge-contrast due to Fresnel diffraction was observed in the magnified images.

Panoramic Dental X-Ray

Science.gov (United States)

... Physician Resources Professions Site Index A-Z Panoramic Dental X-ray Panoramic dental x-ray uses a very small dose of ... x-ray , is a two-dimensional (2-D) dental x-ray examination that captures the entire mouth ...

Development of fast parallel multi-technique scanning X-ray imaging at Synchrotron Soleil

Science.gov (United States)

Medjoubi, K.; Leclercq, N.; Langlois, F.; Buteau, A.; Lé, S.; Poirier, S.; Mercère, P.; Kewish, C. M.; Somogyi, A.

2013-10-01

A fast multimodal scanning X-ray imaging scheme is prototyped at Soleil Synchrotron. It permits the simultaneous acquisition of complementary information on the sample structure, composition and chemistry by measuring transmission, differential phase contrast, small-angle scattering, and X-ray fluorescence by dedicated detectors with ms dwell time per pixel. The results of the proof of principle experiments are presented in this paper.

Soft X-ray multilayers and filters

CERN Document Server

Wang Zhan Shan; Tang Wei Xing; Qin Shuji; Zhou Bing; Chen Ling Ya

2002-01-01

The periodic and non-periodic multilayers were designed by using a random number to change each layer and a suitable merit function. Ion beam sputtering and magnetron sputtering were used to fabricate various multilayers and beam splitters in soft X-ray range. The characterization of multilayers by small angle X-ray diffraction, Auger electron spectroscopy, Rutherford back scattering spectroscopy and reflectivity illustrated the multilayers had good structures and smooth interlayers. The reflectivity and transmission of a beam splitter is about 5%. The fabrication and transmission properties of Ag, Zr were studied. The Rutherford back scattering spectroscopy and auger electron spectroscopy were used to investigate the contents and distributions of impurities and influence on qualities of filters. The attenuation coefficients were corrected by the data obtained by measurements

Protein crowding in solution, frozen and freeze-dried states: small-angle neutron and X-ray scattering study of lysozyme/sorbitol/water systems

Science.gov (United States)

Krueger, Susan; Khodadadi, Sheila; Clark, Nicholas; McAuley, Arnold; Cristiglio, Viviana; Theyencheri, Narayanan; Curtis, Joseph; Shalaev, Evgenyi

2015-03-01

For effective preservation, proteins are often stored as frozen solutions or in glassy states using a freeze-drying process. However, aggregation is often observed after freeze-thaw or reconstitution of freeze-dried powder and the stability of the protein is no longer assured. In this study, small-angle neutron and X-ray scattering (SANS and SAXS) have been used to investigate changes in protein-protein interaction distances of a model protein/cryoprotectant system of lysozyme/sorbitol/water, under representative pharmaceutical processing conditions. The results demonstrate the utility of SAXS and SANS methods to monitor protein crowding at different stages of freezing and drying. The SANS measurements of solution samples showed at least one protein interaction peak corresponding to an interaction distance of ~ 90 Å. In the frozen state, two protein interaction peaks were observed by SANS with corresponding interaction distances at 40 Å as well as 90 Å. On the other hand, both SAXS and SANS data for freeze-dried samples showed three peaks, suggesting interaction distances ranging from ~ 15 Å to 170 Å. Possible interpretations of these interaction peaks will be discussed, as well as the role of sorbitol as a cryoprotectant during the freezing and drying process.

Particle and particle systems characterization small-angle scattering (SAS) applications

CERN Document Server

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.

Visualization of neonatal lung injury associated with mechanical ventilation using x-ray dark-field radiography

Science.gov (United States)

Yaroshenko, Andre; Pritzke, Tina; Koschlig, Markus; Kamgari, Nona; Willer, Konstantin; Gromann, Lukas; Auweter, Sigrid; Hellbach, Katharina; Reiser, Maximilian; Eickelberg, Oliver; Pfeiffer, Franz; Hilgendorff, Anne

2016-04-01

Mechanical ventilation (MV) and supplementation of oxygen-enriched gas, often needed in postnatal resuscitation procedures, are known to be main risk factors for impaired pulmonary development in the preterm and term neonates. Unfortunately, current imaging modalities lack in sensitivity for the detection of early stage lung injury. The present study reports a new imaging approach for diagnosis and staging of early lung injury induced by MV and hyperoxia in neonatal mice. The imaging method is based on the Talbot-Lau x-ray grating interferometry that makes it possible to quantify the x-ray small-angle scattering on the air-tissue interfaces. This so-called dark-field signal revealed increasing loss of x-ray small-angle scattering when comparing images of neonatal mice undergoing hyperoxia and MV-O2 with animals kept at room air. The changes in the dark field correlated well with histologic findings and provided superior differentiation than conventional x-ray imaging and lung function testing. The results suggest that x-ray dark-field radiography is a sensitive tool for assessing structural changes in the developing lung. In the future, with further technical developments x-ray dark-field imaging could be an important tool for earlier diagnosis and sensitive monitoring of lung injury in neonates requiring postnatal oxygen or ventilator therapy.

Structure factor of blends of solvent-free nanoparticle–organic hybrid materials: density-functional theory and small angle X-ray scattering

KAUST Repository

Yu, Hsiu-Yu

2014-09-15

© the Partner Organisations 2014. We investigate the static structure factor S(q) of solvent-free nanoparticle-organic hybrid materials consisting of silica nanocores and space-filling polyethylene glycol coronas using a density-functional theory and small angle X-ray scattering measurements. The theory considers a bidisperse suspension of hard spheres with different radii and tethered bead-spring oligomers with different grafting densities to approximate the polydispersity effects in experiments. The experimental systems studied include pure samples with different silica core volume fractions and the associated mean corona grafting densities, and blends with different mixing ratios of the pure samples, in order to introduce varying polydispersity of corona grafting density. Our scattering experiments and theory show that, compared to the hard-sphere suspension with the same core volume fraction, S(q) for pure samples exhibit both substantially smaller values at small q and stronger particle correlations corresponding to a larger effective hard core at large q, indicating that the tethered incompressible oligomers enforce a more uniform particle distribution, and the densely grafted brush gives rise to an additional exclusionary effect between the nanoparticles. According to the theory, polydispersity in the oligomer grafting density controls the deviation of S(q) from the monodisperse system at smaller q, and the interplay of the enhanced effective core size and the entropic attraction among the particles is responsible for complex variations in the particle correlations at larger q. The successful comparison between the predictions and the measurements for the blends further suggests that S(q) can be used to assess the uniformity of grafting density in polymer-grafted nanoparticle materials. This journal is

Structural analysis of polymer thin films using GISAXS in the tender X-ray region: Concept and design of GISAXS experiments using the tender X-ray energy at BL-15A2 at the Photon Factory

Energy Technology Data Exchange (ETDEWEB)

Takagi, H., E-mail: takagih@post.kek.jp; Igarashi, N.; Mori, T.; Saijo, S.; Nagatani, Y.; Shimizu, N. [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Ohta, H. [Mitsubishi Electric System & Service Co., Ltd, Accelerator Engineering Center, 2-8- 8 Umezono, Tsukuba, Ibaraki 305-0045 (Japan); Yamamoto, K. [Graduate School of Engineering, Department of Materials Science & Technology, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

2016-10-14

If small angle X-ray scattering (SAXS) utilizing the soft X-ray region is available, advanced and unique experiments, which differ from traditional SAXS methods, can be realized. For example, grazing-incidence small angle X-ray scattering (GISAXS) using hard X-ray is a powerful tool for understanding the nanostructure in both vertical and lateral directions of thin films, while GISAXS utilizing the tender X-ray region (SX-GISAXS) enables depth-resolved analysis as well as a standard GISAXS analysis in thin films. Thus, at BL-15A2 at the Photon Factory, a dedicated diffractometer for SX-GISAXS (above 2.1 keV) was constructed. This diffractometer is composed of four vacuum chambers and can be converted into the vacuum state from the sample chamber in front of the detector surface. Diffractions are clearly observed until 12th peak when measuring collagen by SAXS with an X-ray energy of 2.40 keV and a camera length of 825 mm. Additionally, we conducted the model experiment using SX-GISAXS with an X-ray energy of 2.40 keV to confirm that a poly(methyl methacrylate)-poly(n-butyl acrylate) block copolymer thin film has a microphase-separated structure in the thin film, which is composed of lamellae aligned both parallel and perpendicular to the substrate surface. Similarly, in a polystyrene-poly(methyl methacrylate) block copolymer thin film, SX-GISAXS with 3.60 keV and 5.73 keV revealed that hexagonally packed cylinders are aligned parallel to the substrate surface. The incident angle dependence of the first order peak position of the q{sub z} direction obtained from experiments at various incident X-ray energies agrees very well with the theoretical one calculated from the distorted wave Born approximation.

Structural analysis of polymer thin films using GISAXS in the tender X-ray region: Concept and design of GISAXS experiments using the tender X-ray energy at BL-15A2 at the Photon Factory

International Nuclear Information System (INIS)

Takagi, H.; Igarashi, N.; Mori, T.; Saijo, S.; Nagatani, Y.; Shimizu, N.; Ohta, H.; Yamamoto, K.

2016-01-01

If small angle X-ray scattering (SAXS) utilizing the soft X-ray region is available, advanced and unique experiments, which differ from traditional SAXS methods, can be realized. For example, grazing-incidence small angle X-ray scattering (GISAXS) using hard X-ray is a powerful tool for understanding the nanostructure in both vertical and lateral directions of thin films, while GISAXS utilizing the tender X-ray region (SX-GISAXS) enables depth-resolved analysis as well as a standard GISAXS analysis in thin films. Thus, at BL-15A2 at the Photon Factory, a dedicated diffractometer for SX-GISAXS (above 2.1 keV) was constructed. This diffractometer is composed of four vacuum chambers and can be converted into the vacuum state from the sample chamber in front of the detector surface. Diffractions are clearly observed until 12th peak when measuring collagen by SAXS with an X-ray energy of 2.40 keV and a camera length of 825 mm. Additionally, we conducted the model experiment using SX-GISAXS with an X-ray energy of 2.40 keV to confirm that a poly(methyl methacrylate)-poly(n-butyl acrylate) block copolymer thin film has a microphase-separated structure in the thin film, which is composed of lamellae aligned both parallel and perpendicular to the substrate surface. Similarly, in a polystyrene-poly(methyl methacrylate) block copolymer thin film, SX-GISAXS with 3.60 keV and 5.73 keV revealed that hexagonally packed cylinders are aligned parallel to the substrate surface. The incident angle dependence of the first order peak position of the q_z direction obtained from experiments at various incident X-ray energies agrees very well with the theoretical one calculated from the distorted wave Born approximation.

Materials identification using a small-scale pixellated x-ray diffraction system

International Nuclear Information System (INIS)

O’Flynn, D; Crews, C; Drakos, I; Christodoulou, C; Speller, R D; Wilson, M D; Veale, M C; Seller, P

2016-01-01

A transmission x-ray diffraction system has been developed using a pixellated, energy-resolving detector (HEXITEC) and a small-scale, mains operated x-ray source (Amptek Mini-X). HEXITEC enables diffraction to be measured without the requirement of incident spectrum filtration, or collimation of the scatter from the sample, preserving a large proportion of the useful signal compared with other diffraction techniques. Due to this efficiency, sufficient molecular information for material identification can be obtained within 5 s despite the relatively low x-ray source power. Diffraction data are presented from caffeine, hexamine, paracetamol, plastic explosives and narcotics. The capability to determine molecular information from aspirin tablets inside their packaging is demonstrated. Material selectivity and the potential for a sample classification model is shown with principal component analysis, through which each different material can be clearly resolved. (paper)

Observation of X-ray shadings in synchrotron radiation-total reflection X-ray fluorescence using a color X-ray camera

Energy Technology Data Exchange (ETDEWEB)

Fittschen, Ursula Elisabeth Adriane, E-mail: ursula.fittschen@chemie.uni-hamburg.de [Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Menzel, Magnus [Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Scharf, Oliver [IfG Institute for Scientific Instruments GmbH, Berlin (Germany); Radtke, Martin; Reinholz, Uwe; Buzanich, Günther [BAM Federal Institute of Materials Research and Testing, Berlin (Germany); Lopez, Velma M.; McIntosh, Kathryn [Los Alamos National Laboratory, Los Alamos, NM (United States); Streli, Christina [Atominstitut, TU Wien, Vienna (Austria); Havrilla, George Joseph [Los Alamos National Laboratory, Los Alamos, NM (United States)

2014-09-01

Absorption effects and the impact of specimen shape on TXRF analysis has been discussed intensively. Model calculations indicated that ring shaped specimens should give better results in terms of higher counts per mass signals than filled rectangle or circle shaped specimens. One major reason for the difference in signal is shading effects. Full field micro-XRF with a color X-ray camera (CXC) was used to investigate shading, which occurs when working with small angles of excitation as in TXRF. The device allows monitoring the illuminated parts of the sample and the shaded parts at the same time. It is expected that sample material hit first by the primary beam shade material behind it. Using the CXC shading could be directly visualized for the high concentration specimens. In order to compare the experimental results with calculation of the shading effect the generation of controlled specimens is crucial. This was achieved by “drop on demand” technology. It allows generating uniform, microscopic deposits of elements. The experimentally measured shadings match well with those expected from calculation. - Highlights: • Use of a color X-ray camera and drop on demand printing to diagnose X-ray shading • Specimens were obtained uniform and well-defined in shape and concentration by printing. • Direct visualization and determination of shading in such specimens using the camera.

Observation of X-ray shadings in synchrotron radiation-total reflection X-ray fluorescence using a color X-ray camera

International Nuclear Information System (INIS)

Fittschen, Ursula Elisabeth Adriane; Menzel, Magnus; Scharf, Oliver; Radtke, Martin; Reinholz, Uwe; Buzanich, Günther; Lopez, Velma M.; McIntosh, Kathryn; Streli, Christina; Havrilla, George Joseph

2014-01-01

Absorption effects and the impact of specimen shape on TXRF analysis has been discussed intensively. Model calculations indicated that ring shaped specimens should give better results in terms of higher counts per mass signals than filled rectangle or circle shaped specimens. One major reason for the difference in signal is shading effects. Full field micro-XRF with a color X-ray camera (CXC) was used to investigate shading, which occurs when working with small angles of excitation as in TXRF. The device allows monitoring the illuminated parts of the sample and the shaded parts at the same time. It is expected that sample material hit first by the primary beam shade material behind it. Using the CXC shading could be directly visualized for the high concentration specimens. In order to compare the experimental results with calculation of the shading effect the generation of controlled specimens is crucial. This was achieved by “drop on demand” technology. It allows generating uniform, microscopic deposits of elements. The experimentally measured shadings match well with those expected from calculation. - Highlights: • Use of a color X-ray camera and drop on demand printing to diagnose X-ray shading • Specimens were obtained uniform and well-defined in shape and concentration by printing. • Direct visualization and determination of shading in such specimens using the camera

Versatile application of indirect Fourier transformation to structure factor analysis: from X-ray diffraction of molecular liquids to small angle scattering of protein solutions.

Science.gov (United States)

Fukasawa, Toshiko; Sato, Takaaki

2011-02-28

We highlight versatile applicability of a structure-factor indirect Fourier transformation (IFT) technique, hereafter called SQ-IFT. The original IFT aims at the pair distance distribution function, p(r), of colloidal particles from small angle scattering of X-rays (SAXS) and neutrons (SANS), allowing the conversion of the experimental form factor, P(q), into a more intuitive real-space spatial autocorrelation function. Instead, SQ-IFT is an interaction potential model-free approach to the 'effective' or 'experimental' structure factor to yield the pair correlation functions (PCFs), g(r), of colloidal dispersions like globular protein solutions for small-angle scattering data as well as the radial distribution functions (RDFs) of molecular liquids in liquid diffraction (LD) experiments. We show that SQ-IFT yields accurate RDFs of liquid H(2)O and monohydric alcohol reflecting their local intermolecular structures, in which q-weighted structure function, qH(q), conventionally utilized in many LD studies out of necessity of performing direct Fourier transformation, is no longer required. We also show that SQ-IFT applied to theoretically calculated structure factors for uncharged and charged colloidal dispersions almost perfectly reproduces g(r) obtained as a solution of the Ornstein-Zernike (OZ) equation. We further demonstrate the relevance of SQ-IFT in its practical applications, using SANS effective structure factors of lysozyme solutions reported in recent literatures which revealed the equilibrium cluster formation due to coexisting long range electrostatic repulsion and short range attraction between the proteins. Finally, we present SAXS experiments on human serum albumin (HSA) at different ionic strength and protein concentration, in which we discuss the real space picture of spatial distributions of the proteins via the interaction potential model-free route.

X-ray and neutron scattering studies of complex confined fluids

International Nuclear Information System (INIS)

Sinha, S. K.

1999-01-01

We review recent X-ray and neutron scattering studies of the structure and dynamics of confined complex fluids. This includes the study of polymer conformations and binary fluid phase transitions in porous media using Small Angle Neutron scattering, and the use of synchrotrons radiation to study ordering and fluctuation phenomena at solid/liquid and liquid/air interfaces. Ordering of liquids near a solid surface or in confinement will be discussed, and the study, via specular and off-specular X-ray reflectivity, of capillary wave fluctuations on liquid polymer films. Finally, we shall discuss the use of high-brilliance beams from X-ray synchrotrons to study via photon correlation spectroscopy the slow dynamics of soft condensed matter systems

Superhydrophobic surfaces allow probing of exosome self organization using X-ray scattering

KAUST Repository

Accardo, Angelo; Tirinato, Luca; Altamura, Davide; Sibillano, Teresa; Giannini, Cinzia; Riekel, Christian; Di Fabrizio, Enzo M.

2013-01-01

Drops of exosome dispersions from healthy epithelial colon cell line and colorectal cancer cells were dried on a superhydrophobic PMMA substrate. The residues were studied by small- and wide-angle X-ray scattering using both a synchrotron radiation micrometric beam and a high-flux table-top X-ray source. Structural differences between healthy and cancerous cells were detected in the lamellar lattices of the exosome macro-aggregates. © 2013 The Royal Society of Chemistry.

Dependence on incident angle of solid state detector response to gamma-rays

International Nuclear Information System (INIS)

Yamanishi, Hirokuni; Yamaguchi, Satarou; Yamaguchi, Takayuki; Ueki, Kohtaro

2002-01-01

The shape and size of a NaI(Tl) scintillator that should maximize response variation with γ-ray incident angle was estimated by analytical model calculation. It proved that, even for gamma rays of energy exceeding 1 MeV, a slab detector measuring 50 cm x 50 cm x 5 cm thick should present a ratio of at least 4 between maximum and minimum responses against incidence at different angles. For a sample case of 60 keV gamma rays, estimation of the incident angle dependence by means of Monte Carlo simulation agreed well with experiment using a CZT detector. The counts from photo-electric peak varied with incident angle roughly along a sine curve. The foregoing finding served as basis for proposing a practical direction finder for γ-ray source operating on the principle of determining the source direction from variations in count with incident angle. (author)

The over-the-limb hard X-ray events

Science.gov (United States)

Hudson, H. S.

Over-the-limb hard X-ray events offer a uniquely direct view of the hard X-ray emission from the solar corona during a major flare. Limb occultation at angles greater than about 10 deg (an arbitrary definition of this class of events) excludes any confusion with brighter chromospheric sources. Published observations of seven over-the-limb events, beginning with the prototype flare of March 30, 1969, are reviewed. The hard X-ray spectra appear to fall into two classes: hard events, with power-law index of about 2.0; and soft events, with power-law index about 5.4. This tendency towards bimodality is only significant at the 90-percent confidence level due to the smallness of the number of events observed to date. If borne out by future data, the bimodality would suggest the existence of two different acceleration mechanisms.

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)

X-ray streak crystal spectography

International Nuclear Information System (INIS)

Kauffman, R.L.; Brown, T.; Medecki, H.

1983-01-01

We have built an x-ray streaked crystal spectrograph for making time-resolved x-ray spectral measurements. This instrument can access Bragg angles from 11 0 to 38 0 and x-ray spectra from 200 eV to greater than 10 keV. We have demonstrated resolving powers, E/δE > 200 at 1 keV and time resolution less than 20 psec. A description of the instrument and an example of the data is given

Surface characterization of selected polymer thin films by total-reflection x-ray fluorescence spectroscopy and x-ray reflectivity

International Nuclear Information System (INIS)

Innis, Vallerie Ann A.

2006-01-01

Development of available x-ray characterizations tools for grazing incidence techniques was done to be able to probe nano-size thin films. Alignment of a Philips x-ray powder diffractometer was improved to let it perform as an x-ray reflectometer. X-ray reflectometry was coupled with total-reflection x-ray fluorescence spectroscopy. Evaluation of the performance of this grazing incidence techniques was done by preparing polymer thin films of carboxymethylcellulose, carrageenan and polyvinylpyrrolidone (PVP). The thickness of the films were varied by varying the process parameters such as concentration, spin speed and spin time. Angle-dispersive total-reflection x-ray fluorescence spectroscopy profiles of three films showed film formation only in carrageenan and PVP. For both carrageenan and PVP, an increase in concentration yielded a corresponding increase in intensity of the fluorescent or scattered peaks. XRR profiles of carrageenan thin films yielded a mean value for the critical angle close to quartz substrate. Thickness measurements of the prepared carrageenan thin films showed that concentration was the main determinant for final film thickness over the other process parameters. Sulfur fluorescent intensity derived from the TXRF measurement showed a linear relationship with the measured thickness by XRR. For PVP, measured critical angle is lower than quartz. Poor adhesion of the polymer onto the substrate yielded a limited number of thickness measurements made from the XRR profiles. (Author)

Abstract ID: 176 Geant4 implementation of inter-atomic interference effect in small-angle coherent X-ray scattering for materials of medical interest.

Science.gov (United States)

Paternò, Gianfranco; Cardarelli, Paolo; Contillo, Adriano; Gambaccini, Mauro; Taibi, Angelo

2018-01-01

Advanced applications of digital mammography such as dual-energy and tomosynthesis require multiple exposures and thus deliver higher dose compared to standard mammograms. A straightforward manner to reduce patient dose without affecting image quality would be removal of the anti-scatter grid, provided that the involved reconstruction algorithms are able to take the scatter figure into account [1]. Monte Carlo simulations are very well suited for the calculation of X-ray scatter distribution and can be used to integrate such information within the reconstruction software. Geant4 is an open source C++ particle tracking code widely used in several physical fields, including medical physics [2,3]. However, the coherent scattering cross section used by the standard Geant4 code does not take into account the influence of molecular interference. According to the independent atomic scattering approximation (the so-called free-atom model), coherent radiation is indistinguishable from primary radiation because its angular distribution is peaked in the forward direction. Since interference effects occur between x-rays scattered by neighbouring atoms in matter, it was shown experimentally that the scatter distribution is affected by the molecular structure of the target, even in amorphous materials. The most important consequence is that the coherent scatter distribution is not peaked in the forward direction, and the position of the maximum is strongly material-dependent [4]. In this contribution, we present the implementation of a method to take into account inter-atomic interference in small-angle coherent scattering in Geant4, including a dedicated data set of suitable molecular form factor values for several materials of clinical interest. Furthermore, we present scatter images of simple geometric phantoms in which the Rayleigh contribution is rigorously evaluated. Copyright © 2017.

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... of knee x-rays. A portable x-ray machine is a compact apparatus that can be taken ... of the body being examined, an x-ray machine produces a small burst of radiation that passes ...

Anomalous effect of small doses of ionizing radiation on metals and alloys

International Nuclear Information System (INIS)

Chernov, I.P.; Mamontov, A.P.; Botaki, A.A.; Cherdantsev, P.A.; Chakhlov, B.V.; Sharov, S.R.; Timoshnikov, Yu.A.; Filipenko, L.A.

1986-01-01

The effect of small doses of 60 Co gamma rays on copper, tungsten, and WCo alloys has been investigated. A decrease in the concentration of material defects under the influence of small doses of ionizing radiation was found. Also the structural rearrangement of the crystal was found to be still in progress after irradiation ceased. The mechanism of the anomalous effect of small doses of ionizing radiation on metals and alloys is discussed in terms of the electron energy scheme. (U.K.)

Time-resolved small-angle x-ray scattering study of the early stage of amyloid formation of an apomyoglobin mutant

Science.gov (United States)

Ortore, Maria Grazia; Spinozzi, Francesco; Vilasi, Silvia; Sirangelo, Ivana; Irace, Gaetano; Shukla, Anuj; Narayanan, Theyencheri; Sinibaldi, Raffaele; Mariani, Paolo

2011-12-01

The description of the fibrillogenesis pathway and the identification of “on-pathway” or “off-pathway” intermediates are key issues in amyloid research as they are concerned with the mechanism for onset of certain diseases and with therapeutic treatments. Recent results on the fibril formation process revealed an unexpected complexity both in the number and in the types of species involved, but the early aggregation events are still largely unknown, mainly because of their experimental inaccessibility. To provide information on the early stage events of self-assembly of an amyloidogenic protein, during the so-called lag phase, stopped-flow time-resolved small angle x-ray scattering (SAXS) experiments were performed. Using a global fitting analysis, the structural and aggregation properties of the apomyoglobin W7FW14F mutant, which is monomeric and partly folded at acidic pH but forms amyloid fibrils after neutralization, were derived from the first few milliseconds onward. SAXS data indicated that the first aggregates appear in less than 20 ms after the pH jump to neutrality and further revealed the simultaneous presence of diverse species. In particular, worm-like unstructured monomers, very large assemblies, and elongated particles were detected, and their structural features and relative concentrations were derived as a function of time on the basis of our model. The final results show that, during the lag phase, early assembling occurs due to the presence of transient monomeric species very prone to association and through successive competing aggregation and rearrangement processes leading to coexisting on-pathway and off-pathway transient species.

Improving packaged food quality and safety. Part 1: synchrotron X-ray analysis.

Science.gov (United States)

López-Rubio, A; Hernandez-Muñoz, P; Catala, R; Gavara, R; Lagarón, J M

2005-10-01

The objective was to demonstrate, as an example of an application, the potential of synchrotron X-ray analysis to detect morphological alterations that can occur in barrier packaging materials and structures. These changes can affect the packaging barrier characteristics when conventional food preservation treatments are applied to packaged food. The paper presents the results of a number of experiments where time-resolved combined wide-angle X-ray scattering and small-angle X-ray scattering analysis as a function of temperature and humidity were applied to ethylene-vinyl alcohol co-polymers (EVOH), polypropylene (PP)/EVOH/PP structures, aliphatic polyketone terpolymer (PK) and amorphous polyamide (aPA) materials. A comparison between conventional retorting and high-pressure processing treatments in terms of morphologic alterations are also presented for EVOH. The impact of retorting on the EVOH structure contrasts with the good behaviour of the PK during this treatment and with that of aPA. However, no significant structural changes were observed by wide-angle X-ray scattering in the EVOH structures after high-pressure processing treatment. These structural observations have also been correlated with oxygen permeability measurements that are of importance when guaranteeing the intended levels of safety and quality of packaged food.

X-ray Fluorescence Spectroscopy: the Potential of Astrophysics-developed Techniques

Science.gov (United States)

Elvis, M.; Allen, B.; Hong, J.; Grindlay, J.; Kraft, R.; Binzel, R. P.; Masterton, R.

2012-12-01

X-ray fluorescence from the surface of airless bodies has been studied since the Apollo X-ray fluorescence experiment mapped parts of the lunar surface in 1971-1972. That experiment used a collimated proportional counter with a resolving power of ~1 and a beam size of ~1degree. Filters separated only Mg, Al and SI lines. We review progress in X-ray detectors and imaging for astrophysics and show how these advances enable much more powerful use of X-ray fluorescence for the study of airless bodies. Astrophysics X-ray instrumentation has developed enormously since 1972. Low noise, high quantum efficiency, X-ray CCDs have flown on ASCA, XMM-Newton, the Chandra X-ray Observatory, Swift and Suzaku, and are the workhorses of X-ray astronomy. They normally span 0.5 to ~8 keV with an energy resolution of ~100 eV. New developments in silicon based detectors, especially individual pixel addressable devices, such as CMOS detectors, can withstand many orders of magnitude more radiation than conventional CCDs before degradation. The capability of high read rates provides dynamic range and temporal resolution. Additionally, the rapid read rates minimize shot noise from thermal dark current and optical light. CMOS detectors can therefore run at warmer temperatures and with ultra-thin optical blocking filters. Thin OBFs mean near unity quantum efficiency below 1 keV, thus maximizing response at the C and O lines.such as CMOS detectors, promise advances. X-ray imaging has advanced similarly far. Two types of imager are now available: specular reflection and coded apertures. X-ray mirrors have been flown on the Einstein Observatory, XMM-Newton, Chandra and others. However, as X-ray reflection only occurs at small (~1degree) incidence angles, which then requires long focal lengths (meters), mirrors are not usually practical for planetary missions. Moreover the field of view of X-ray mirrors is comparable to the incident angle, so can only image relatively small regions. More useful

Wide-angle X-ray scattering study of heat-treated PEEK and PEEK composite

Science.gov (United States)

Cebe, Peggy; Lowry, Lynn; Chung, Shirley Y.; Yavrouian, Andre; Gupta, Amitava

1987-01-01

Samples of poly(etheretherketone) (PEEK) neat resin and APC-2 carbon fiber composite were subjected to various heat treatments, and the effect of quenching and annealing treatments was studied by wide-angle X-ray scattering. It is found that high-temperature treatments may introduce disorder into neat resin and composite PEEK when followed by rapid cooling. The disorder is metastable and can revert to ordered state when the material is heated above its glass transition temperature and then cooled slowly. The disorder may result from residual thermal stresses.

Pulmonary emphysema diagnosis using a preclinical small-animal X-ray dark-field scanner

Energy Technology Data Exchange (ETDEWEB)

Yaroshenko, Andre; Bech, Martin; Tapfer, Arne; Velroyen, Astrid; Pfeiffer, Franz [Department of Physics, Technische Universitaet Muenchen (Germany); Meinel, Felix; Nikolaou, Konstantin; Reiser, Maximilian [Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Muenchen (Germany); Bohla, Alexander; Yildirim, Ali Oender; Eickelberg, Oliver [Institute of Lung Biology and Disease, Helmholtz Zentrum Muenchen (Germany)

2013-07-01

Pulmonary emphysema is one of the leading causes of morbidity and mortality worldwide that is difficult to detect using conventional x-ray radiographic methods. For emphysematous lungs with enlarged distal airspaces, x-ray scattering decreases and transmission increases, as has been demonstrated by the proof-of-principle experiments with brilliant x-rays from a synchrotron source. Therefore, combination of the transmission and dark-field signals leads to a novel diagnostic approach for pulmonary emphysema. In this study, images of excised murine lungs with pulmonary emphysema and control lungs were acquired using a compact phase- and dark-field scanner with a polychromatic source and a cone-beam geometry. The data analysis revealed a clear distinction between the two groups in the per-pixel scatter plot. The main difference was observed in the angle of the distribution to the vertical. The presented study reveals the high potential of the approach for the pulmonary emphysema diagnosis.

Chest X-Ray (Chest Radiography)

Science.gov (United States)

... Resources Professions Site Index A-Z X-ray (Radiography) - Chest Chest x-ray uses a very small dose ... Radiography? What is a Chest X-ray (Chest Radiography)? The chest x-ray is the most commonly performed diagnostic ...

Photoluminescence studies on Cd(1-x)Zn(x)S:Mn2+ nanocrystals.

Science.gov (United States)

Sethi, Ruchi; Kumar, Lokendra; Pandey, A C

2009-09-01

Highly monodispersed, undoped and doped with Mn2+, binary and ternary (CdS, ZnS, Cd(1-x)Zn(x)S) compound semiconductor nanocrystals have been synthesized by co-precipitation method using citric acid as a stabilizer. As prepared sample are characterized by X-ray diffraction, Small angle X-ray scattering, Transmission electron microscope, Optical absorption and Photoluminescence spectroscopy, for their optical and structural properties. X-ray diffraction, Small angle X-ray scattering and Transmission electron microscope results confirm the preparation of monodispersed nanocrystals. Photoluminescence studies show a significant blue shift in the wavelength with an increasing concentration of Zn in alloy nanocrystals.

Measuring the molecular dimensions of wine tannins: comparison of small-angle X-ray scattering, gel-permeation chromatography and mean degree of polymerization.

Science.gov (United States)

McRae, Jacqui M; Kirby, Nigel; Mertens, Haydyn D T; Kassara, Stella; Smith, Paul A

2014-07-23

The molecular size of wine tannins can influence astringency, and yet it has been unclear as to whether the standard methods for determining average tannin molecular weight (MW), including gel-permeation chromatography (GPC) and depolymerization reactions, are actually related to the size of the tannin in wine-like conditions. Small-angle X-ray scattering (SAXS) was therefore used to determine the molecular sizes and corresponding MWs of wine tannin samples from 3 and 7 year old Cabernet Sauvignon wine in a variety of wine-like matrixes: 5-15% and 100% ethanol; 0-200 mM NaCl and pH 3.0-4.0, and compared to those measured using the standard methods. The SAXS results indicated that the tannin samples from the older wine were larger than those of the younger wine and that wine composition did not greatly impact on tannin molecular size. The average tannin MWs as determined by GPC correlated strongly with the SAXS results, suggesting that this method does give a good indication of tannin molecular size in wine-like conditions. The MW as determined from the depolymerization reactions did not correlate as strongly with the SAXS results. To our knowledge, SAXS measurements have not previously been attempted for wine tannins.

Constrained Maximum Likelihood Estimation of Relative Abundances of Protein Conformation in a Heterogeneous Mixture from Small Angle X-Ray Scattering Intensity Measurements

Science.gov (United States)

Onuk, A. Emre; Akcakaya, Murat; Bardhan, Jaydeep P.; Erdogmus, Deniz; Brooks, Dana H.; Makowski, Lee

2015-01-01

In this paper, we describe a model for maximum likelihood estimation (MLE) of the relative abundances of different conformations of a protein in a heterogeneous mixture from small angle X-ray scattering (SAXS) intensities. To consider cases where the solution includes intermediate or unknown conformations, we develop a subset selection method based on k-means clustering and the Cramér-Rao bound on the mixture coefficient estimation error to find a sparse basis set that represents the space spanned by the measured SAXS intensities of the known conformations of a protein. Then, using the selected basis set and the assumptions on the model for the intensity measurements, we show that the MLE model can be expressed as a constrained convex optimization problem. Employing the adenylate kinase (ADK) protein and its known conformations as an example, and using Monte Carlo simulations, we demonstrate the performance of the proposed estimation scheme. Here, although we use 45 crystallographically determined experimental structures and we could generate many more using, for instance, molecular dynamics calculations, the clustering technique indicates that the data cannot support the determination of relative abundances for more than 5 conformations. The estimation of this maximum number of conformations is intrinsic to the methodology we have used here. PMID:26924916

Exchange interpretation of anomalous back angle heavy ion elastic scattering

International Nuclear Information System (INIS)

Zisman, M.S.

1977-10-01

Anomalous back angle oscillations in the angular distributions obtained in the elastic scattering of 16 O + 28 Si and 12 C + 28 Si have been interpreted in terms of an elastic cluster transfer comparable to that observed in other heavy ion reactions. The calculations appear to at least qualitatively explain the data with respect to the existence and phase of the back angle oscillations. The results indicate that an exchange mechanism may play an important role in the oscillations

Nanoparticle-Assisted Scanning Focusing X-Ray Therapy with Needle Beam X Rays.

Science.gov (United States)

Davidson, R Andrew; Guo, Ting

2016-01-01

In this work, we show a new therapeutic approach using 40-120 keV X rays to deliver a radiation dose at the isocenter located many centimeters below the skin surface several hundred times greater than at the skin and how this dose enhancement can be augmented with nanomaterials to create several thousand-fold total dose enhancement effect. This novel approach employs a needle X-ray beam directed at the isocenter centimeters deep in the body while continuously scanning the beam to cover a large solid angle without overlapping at the skin. A Monte Carlo method was developed to simulate an X-ray dose delivered to the isocenter filled with X-ray absorbing and catalytic nanoparticles in a water phantom. An experimental apparatus consisting of a moving plastic phantom irradiated with a stationary 1 mm needle X-ray beam was built to test the theoretical predictions. X-ray films were used to characterize the dose profiles of the scanning X-ray apparatus. Through this work, it was determined that the X-ray dose delivered to the isocenter in a treatment voxel (t-voxel) underneath a 5 cm deep high-density polyethylene (HDPE) phantom was 295 ± 48 times greater than the surface dose. This measured value was in good agreement with the theoretical predicted value of 339-fold. Adding X-ray-absorbing nanoparticles, catalytic nanoparticles or both into the t-voxel can further augment the dose enhancement. For example, we predicted that adding 1 weight percentage (wp) of gold into water could increase the effective dose delivered to the target by onefold. Dose enhancement using 1 mm X-ray beam could reach about 1,600-fold in the t-voxel when 7.5 wp of 88 nm diameter silica-covered gold nanoparticles were added, which we showed in a previously published study can create a dose enhancement of 5.5 ± 0.46-fold without scanning focusing enhancement. Based on the experimental data from that study, mixing 0.02 wp 2.5 nm diameter small tetrakis hydroxymethyl phosphonium chloride (THPC

Improved In vivo Assessment of Pulmonary Fibrosis in Mice using X-Ray Dark-Field Radiography

Science.gov (United States)

Yaroshenko, Andre; Hellbach, Katharina; Yildirim, Ali Önder; Conlon, Thomas M.; Fernandez, Isis Enlil; Bech, Martin; Velroyen, Astrid; Meinel, Felix G.; Auweter, Sigrid; Reiser, Maximilian; Eickelberg, Oliver; Pfeiffer, Franz

2015-12-01

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease with a median life expectancy of 4-5 years after initial diagnosis. Early diagnosis and accurate monitoring of IPF are limited by a lack of sensitive imaging techniques that are able to visualize early fibrotic changes at the epithelial-mesenchymal interface. Here, we report a new x-ray imaging approach that directly visualizes the air-tissue interfaces in mice in vivo. This imaging method is based on the detection of small-angle x-ray scattering that occurs at the air-tissue interfaces in the lung. Small-angle scattering is detected with a Talbot-Lau interferometer, which provides the so-called x-ray dark-field signal. Using this imaging modality, we demonstrate-for the first time-the quantification of early pathogenic changes and their correlation with histological changes, as assessed by stereological morphometry. The presented radiography method is significantly more sensitive in detecting morphological changes compared with conventional x-ray imaging, and exhibits a significantly lower radiation dose than conventional x-ray CT. As a result of the improved imaging sensitivity, this new imaging modality could be used in future to reduce the number of animals required for pulmonary research studies.

Cosmic ray zenith angle distribution at low geomagnetic latitude

Energy Technology Data Exchange (ETDEWEB)

Aragon, G [Instituto de Astronomia y Fisica del Espacio, Buenos Aires, Argentina; Gagliardini, A; Ghielmetti, H S

1977-12-01

The intensity of secondary charged cosmic rays at different zenith angles was measured by narrow angle Geiger-Mueller telescopes up to an atmospheric depth of 2 g cm/sup -2/. The angular distribution observed at high altitudes is nearly flat at small angles around the vertical and suggests that the particle intensity peaks at large zenith angles, close to the horizon.

X-ray imaging system

International Nuclear Information System (INIS)

Houston, J.M.

1980-01-01

A novel, high-speed apparatus for use in X-ray computerised tomography is described in detail. It consists of a semi-circular array of X-ray sources, collimators and an ion chamber array for detection of the X-rays. The X-ray sources may be pulsed in salvos such that the corresponding detectors in the array are only illuminated by one source. The use of computer controlled salvos speeds up the image processing by at least a factor of two. The ion chamber array is designed to have a constant detection efficiency for varying angles of X-ray incidence. A detailed description of the detector construction and suggested gaseous fillings are given. It is claimed that the present tomographic system allows fast and accurate imaging of internal body organs and is insensitive to the blurring effects which motion of these organs tends to produce. (UK)

Energy-angle correlation correction algorithm for monochromatic computed tomography based on Thomson scattering X-ray source

Science.gov (United States)

Chi, Zhijun; Du, Yingchao; Huang, Wenhui; Tang, Chuanxiang

2017-12-01

The necessity for compact and relatively low cost x-ray sources with monochromaticity, continuous tunability of x-ray energy, high spatial coherence, straightforward polarization control, and high brightness has led to the rapid development of Thomson scattering x-ray sources. To meet the requirement of in-situ monochromatic computed tomography (CT) for large-scale and/or high-attenuation materials based on this type of x-ray source, there is an increasing demand for effective algorithms to correct the energy-angle correlation. In this paper, we take advantage of the parametrization of the x-ray attenuation coefficient to resolve this problem. The linear attenuation coefficient of a material can be decomposed into a linear combination of the energy-dependent photoelectric and Compton cross-sections in the keV energy regime without K-edge discontinuities, and the line integrals of the decomposition coefficients of the above two parts can be determined by performing two spectrally different measurements. After that, the line integral of the linear attenuation coefficient of an imaging object at a certain interested energy can be derived through the above parametrization formula, and monochromatic CT can be reconstructed at this energy using traditional reconstruction methods, e.g., filtered back projection or algebraic reconstruction technique. Not only can monochromatic CT be realized, but also the distributions of the effective atomic number and electron density of the imaging object can be retrieved at the expense of dual-energy CT scan. Simulation results validate our proposal and will be shown in this paper. Our results will further expand the scope of application for Thomson scattering x-ray sources.

Giant Rapid X-ray Flares in Extragalactic Globular Clusters

Science.gov (United States)

Irwin, Jimmy

2018-01-01

There is only one known class of non-destructive, highly energetic astrophysical object in the Universe whose energy emission varies by more than a factor of 100 on time scales of less than a minute -- soft gamma repeaters/anomalous X-ray pulsars, whose flares are believed to be caused by the energy release from the cracking of a neutron star's surface by very strong magnetic fields. All other known violent, rapid explosions, including gamma-ray bursts and supernovae, are believed to destroy the object in the process. Here, we report the discovery of a second class of non-destructive, highly energetic rapidly flaring X-ray object located within two nearby galaxies with fundamentally different properties than soft gamma repeaters/anomalous X-ray pulsars. One source is located within a suspected globular cluster of the host galaxy and flared one time, while the other source is located in either a globular cluster of the host galaxy or the core of a stripped dwarf companion galaxy that flared on six occasions over a seven year time span. When not flaring, the sources appear as normal accreting neutron star or black hole X-ray binaries, indicating that the flare event does not significantly disrupt the host system. While the nature of these sources is still unclear, the discovery of these sources in decade-old archival Chandra X-ray Observatory data illustrates the under-utilization of X-ray timing as a means to discover new classes of explosive events in the Universe.

Interdiffusion in nanometer-scale multilayers investigated by in situ low-angle x-ray diffraction

Science.gov (United States)

Wang, Wei-Hua; Bai, Hai Yang; Zhang, Ming; Zhao, J. H.; Zhang, X. Y.; Wang, W. K.

1999-04-01

An in situ low-angle x-ray diffraction technique is used to investigate interdiffusion phenomena in various metal-metal and metal-amorphous Si nanometer-scale compositionally modulated multilayers (ML's). The temperature-dependent interdiffusivities are obtained by accurately monitoring the decay of the first-order modulation peak as a function of annealing time. Activation enthalpies and preexponential factors for the interdiffusion in the Fe-Ti, Ag-Bi, Fe-Mo, Mo-Si, Ni-Si, Nb-Si, and Ag-Si ML's are determined. Activation enthalpies and preexponential factors for the interdiffusion in the ML's are very small compared with that in amorphous alloys and crystalline solids. The relation between the atomic-size difference and interdiffusion in the ML's are investigated. The observed interdiffusion characteristics are compared with that in amorphous alloys and crystalline α-Zr, α-Ti, and Si. The experimental results suggest that a collective atomic-jumping mechanism govern the interdiffusion in the ML's, the collective proposal involving 8-15 atoms moving between extended nonequilibrium defects by thermal activation. The role of the interdiffusion in the solid-state reaction in the ML's is also discussed.

Using acoustic levitation in synchrotron based laser pump hard x-ray probe experiments

Science.gov (United States)

Hu, Bin; Lerch, Jason; Suthar, Kamlesh; Dichiara, Anthony

Acoustic levitation provides a platform to trap and hold a small amount of material by using standing pressure waves without a container. The technique has a potential to be used for laser pump x-ray probe experiments; x-ray scattering and laser distortion from the container can be avoided, sample consumption can be minimized, and unwanted chemistry that may occur at the container interface can be avoided. The method has been used at synchrotron sources for studying protein and pharmaceutical solutions using x-ray diffraction (XRD) and small angle x-ray scattering (SAXS). However, pump-probe experiments require homogeneously excited samples, smaller than the absorption depth of the material that must be held stably at the intersection of both the laser and x-ray beams. We discuss 1) the role of oscillations in acoustic levitation and the optimal acoustic trapping conditions for x-ray/laser experiments, 2) opportunities to automate acoustic levitation for fast sample loading and manipulation, and 3) our experimental results using SAXS to monitor laser induced thermal expansion in gold nanoparticles solution. We also performed Finite Element Analysis to optimize the trapping performance and stability of droplets ranging from 0.4 mm to 2 mm. Our early x-ray/laser demonstrated the potential of the technique for time-resolved X-ray science.

An anomalous X-ray scattering study on glassy superionic conductor (As2Se3)1-x(CuI) x using a third-generation synchrotron radiation facility

International Nuclear Information System (INIS)

Usuki, T.; Hosokawa, S.; Berar, J.-F.

2005-01-01

Anomalous X-ray scattering experiments on glassy superionic conductor (As 2 Se 3 ) 0.4 (CuI) 0.6 were performed at energies close to the As, Se, and Cu K edges using a new detecting system and a third-generation synchrotron radiation facility. The detecting system was composed of a graphite-crystal energy-analyzer and a NaI(Tl) detector on a 40-cm-long arm. The overall energy resolution was about 60 eV, which can discriminate the elastic signal from the fluorescence and Compton contributions, and a sufficient number of scattered X-ray photons were acquired within a reasonable data collection time. The differential structure factors, Δ i S(Q), were obtained from the detailed analyses, indicating that Δ As S(Q) and Δ Se S(Q) are similar to those of glassy As 2 Se 3 except at the prepeak position, and Δ Cu S(Q) that in liquid CuI. From these findings, it can be concluded that a pseudo-binary mixture of the As 2 Se 3 network matrix and CuI-related conduction pathways would be a good structural model for this superionic glass

Synchrotron x-ray sources and new opportunities in the soil and environmental sciences

International Nuclear Information System (INIS)

Schulze, D.; Anderson, S.; Mattigod, S.

1990-07-01

This report contains the following papers: characteristics of the advanced photon source and comparison with existing synchrotron facilities; x-ray absorption spectroscopy: EXAFS and XANES -- A versatile tool to study the atomic and electronic structure of materials; applications of x-ray spectroscopy and anomalous scattering experiments in the soil and environmental sciences; X-ray fluorescence microprobe and microtomography

X-ray topography under conditions of monochromatic spherical wave diffraction

International Nuclear Information System (INIS)

Aristov, V.V.; Polovinkina, V.I.; Ibhikawa, Tetsuya; Kiduta, Seishi.

1981-01-01

An X-ray topographic scheme was developed in which there is a large distance between the X-ray source and the specimen. A monochromatic X-ray beam with an angular divergence 6 x 10 - 5 rad obtained by double successive diffraction in the (n 1 , +n 2 ) setting was used. This scheme enables diffraction focusing of a weakly absorbed wave field onto the exit surface of the crystal to be performed. Topographs of a wedge-shaped silicon crystal were obtained. Interference effects such as focusing, anomalous and ordinary Pendelloesung effects peculiar to X-ray spherical wave diffraction were observed in the topographs with high resolution. (author)

DISCOVERY OF X-RAY EMISSION FROM YOUNG SUNS IN THE SMALL MAGELLANIC CLOUD

International Nuclear Information System (INIS)

Oskinova, L. M.; Hainich, R.; Sun, W.; Chen, Y.; Evans, C. J.; Hénault-Brunet, V.; Chu, Y.-H.; Gruendl, R. A.; Gallagher, J. S. III; Guerrero, M. A.; Güdel, M.; Silich, S.; Nazé, Y.; Reyes-Iturbide, J.

2013-01-01

We report the discovery of extended X-ray emission within the young star cluster NGC 602a in the Wing of the Small Magellanic Cloud (SMC) based on observations obtained with the Chandra X-Ray Observatory. X-ray emission is detected from the cluster core area with the highest stellar density and from a dusty ridge surrounding the H II region. We use a census of massive stars in the cluster to demonstrate that a cluster wind or wind-blown bubble is unlikely to provide a significant contribution to the X-ray emission detected from the central area of the cluster. We therefore suggest that X-ray emission at the cluster core originates from an ensemble of low- and solar-mass pre-main-sequence (PMS) stars, each of which would be too weak in X-rays to be detected individually. We attribute the X-ray emission from the dusty ridge to the embedded tight cluster of the newborn stars known in this area from infrared studies. Assuming that the levels of X-ray activity in young stars in the low-metallicity environment of NGC 602a are comparable to their Galactic counterparts, then the detected spatial distribution, spectral properties, and level of X-ray emission are largely consistent with those expected from low- and solar-mass PMS stars and young stellar objects (YSOs). This is the first discovery of X-ray emission attributable to PMS stars and YSOs in the SMC, which suggests that the accretion and dynamo processes in young, low-mass objects in the SMC resemble those in the Galaxy.

Preliminary Examination of X-ray Scattering from Human Tissues

International Nuclear Information System (INIS)

Desouky, O.S.; Wilkinson, S.; Hall, C.; Rogers, K.; Round, A.

2008-01-01

Small Angle x-ray scattering (SAXS) and wide angle x-ray scattering (WAXS) patterns have been recorded from different human soft tissues using x-ray synchrotron radiation.Pathological breast, normal kidney and lung tissues show SAXS peaks at q-values equal to 0.291 nm -1 and 0.481 nm -1 (d 21.6 nm and d =13. nm) which are the 3 r d and 5 t h order of the well known axial D-spacing of collagen fibrils. The diffraction is particularly intense in the meridional direction indicating some febrile alignment. In contrast, the normal tissue of brain, liver and heart shows diffuse scatter.The wide-angle coherent scattering from normal human tissues of brain, liver, heart, lung, and kidney is typical of that for amorphous materials. The scatter of the healthy adipose breast tissue shows a sharp peak at momentum transfer 1.24 nm -1 (d= 0.417 nm). The data of the other tissues appears to consist of a broad scattering peak. The two scattering regimes succeed in differentiating between the two major components of breast tissue, collagen and adipose tissue. The results of this study suggest that the soft tissues may have scattering patterns that are characteristics for the particular tissue types and tissue disease state. These results indicate that it may be possible use the coherent scattering as a diagnostic tool

Bone X-Ray (Radiography)

Medline Plus

Full Text Available ... X-rays are a form of radiation like light or radio waves. X-rays pass through most objects, including the body. Once it is carefully aimed at the part of the body being examined, an x-ray machine produces a small ...

New insights into nucleation. Pressure trace measurements and the first small angle X-ray scattering experiments in a supersonic laval nozzle

International Nuclear Information System (INIS)

Ghosh, D.

2007-01-01

Homogeneous nucleation rates of the n-alcohols and the n-alkanes have been determined by combining information from two sets of supersonic Laval nozzle expansion experiments under identical conditions. The nucleation rates J=N/Δt Jmax for the n-alcohols are in the range of 1.10 17 -3 s -1 17 for the temperatures 207≤T/K≤249, the nucleation rates for the n-alkanes lie in the range of 5.10 15 -3 s -1 18 for the temperatures 143 ≤T/K≤215. For the first time it is shown that the nucleation rate is not only a function of the supersaturation and temperature but clearly also sensitive to the expansion rate during supersonic nozzle expansion. A good agreement between the experimental results and those available in literature is found by applying Hale's scaling formalism [Hale, B., Phys. Rev. A 33, 4256 (1986); Hale, B., Metall. Trans. A 23, 1863 (1992)]. The scaling parameters from this work are also in good agreement with those shown by Rusyniak et al. [Rusyniak, M., M. S. El-Shall, J. Phys. Chem. B 105, 11873 (2001)] and Brus et al. [Brus, D., V. Zdimal F. Stratmann, J. Chem Phys. 124, 164306 (2006)]. In the first experiment static pressure measurements were conducted for the n-alkanes to determine the condensible partial pressure, temperature, supersaturation, characteristic time, and the expansion rate corresponding to the maximum nucleation rate. Characteristic times in the range of 13≤Δt Jmax /μs≤34 were found. In the second set of experiments, the first flow rate resolved Small Angle X-ray Scattering experiments are conducted to determine the particle number density for both substance classes. Particle number densities in the range of 1.10 12 -3 12 and 1.10 11 -3 12 for the n-alcohols and n-alkanes are found, respectively. Additionally, by analyzing the radially averaged scattering spectrum, information on the mean radius and the width of the size distribution of the aerosols is obtained. Mean radii for the n-alcohols in the range of 4< left angle r

Differential dose albedo for high-energy X-rays on concrete slab

International Nuclear Information System (INIS)

Kato, Hideki

2006-01-01

We computed the differential dose albedo (α D ) for high-energy X-rays on a concrete slab when the incident angle, reflection angle, and azimuth angle were changed, by means of Monte Carlo simulation. We found that α D changed with incident, reflection, and azimuth angles to the concrete slab. On the whole, the larger the incident angle, the larger α D tended to become. If the incident angle and reflection angle were the same, the larger the azimuth angle, the smaller α D tended to become. When the incident, reflection, and azimuth angles were the same, the smaller the X-ray energy was, the larger α D became, in the order of 10 MV, 6 MV, and 4 MV X-rays. (author)

Accounting for thermodynamic non-ideality in the Guinier region of small-angle scattering data of proteins.

Science.gov (United States)

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.

Changes in the shapes of self-organized PbSe quantum dots during PbEuTe overgrowth investigated by anomalous X-ray diffraction

International Nuclear Information System (INIS)

Holy, V.; Schuelli, T.U.; Lechner, R.T.; Springholz, G.; Bauer, G.

2006-01-01

Anomalous X-ray diffraction was used for the investigation of shape and chemical composition of self-organized PbSe quantum dots covered by PbEuTe capping layers. From reciprocal-space maps of diffracted intensities measured at two energies of the primary radiation, we discriminated the contributions of the dot volumes and the surrounding crystal lattice to the diffracted intensity. We have found that the presence of Eu atoms suppresses the flattening of the dots during their overgrowth

Hartman Testing of X-Ray Telescopes

Science.gov (United States)

Saha, Timo T.; Biskasch, Michael; Zhang, William W.

2013-01-01

Hartmann testing of x-ray telescopes is a simple test method to retrieve and analyze alignment errors and low-order circumferential errors of x-ray telescopes and their components. A narrow slit is scanned along the circumference of the telescope in front of the mirror and the centroids of the images are calculated. From the centroid data, alignment errors, radius variation errors, and cone-angle variation errors can be calculated. Mean cone angle, mean radial height (average radius), and the focal length of the telescope can also be estimated if the centroid data is measured at multiple focal plane locations. In this paper we present the basic equations that are used in the analysis process. These equations can be applied to full circumference or segmented x-ray telescopes. We use the Optical Surface Analysis Code (OSAC) to model a segmented x-ray telescope and show that the derived equations and accompanying analysis retrieves the alignment errors and low order circumferential errors accurately.

X-ray directional dark-field contrast for sub-pixel resolution imaging of bone microstructures

Energy Technology Data Exchange (ETDEWEB)

Biernath, Thomas; Malecki, Andreas; Potdevin, Guillaume; Bech, Martin; Pfeiffer, Franz [Department of Physics (E17) and Institute of Medical Engineering (IMETUM), Technische Universitaet Muenchen (Germany); Jensen, Torben [Niels Bohr Institute, University of Copenhagen (Denmark)

2011-07-01

The basic principles of X-ray image formation in radiography have remained essentially unchanged since Roentgen first discovered X-rays over a hundred years ago. The conventional approach relies on X-ray absorption as the sole source of contrast and thus gives an information about the density changes in the sample. The recently introduced X-ray dark field imaging technique (DFI) yields a fundamentally different signal: DFI is a measure of the sample small angle scattering signal and thus yields information about the sample microstructure. Such measurements can be effectively performed thanks to a Laue-Talbot grating interferometer. This presentation shows recent experimental directional dark-field imaging results of various samples both from synchrotron and classical X-ray tube sources.

The superconducting high-resolution soft X-ray spectrometer at the advanced biological and environmental X-ray facility

Energy Technology Data Exchange (ETDEWEB)

Friedrich, S. [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-188, Livermore, CA 94550 (United States); Advanced Biological and Environmental X-ray Facility, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 6-2100, Berkeley, CA 94720 (United States)], E-mail: Friedrich1@llnl.gov; Drury, O.B. [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-188, Livermore, CA 94550 (United States); Advanced Biological and Environmental X-ray Facility, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 6-2100, Berkeley, CA 94720 (United States); Biophysics Group, University of California, 1 Shields Avenue, EU-III, Davis, CA 95616 (United States); George, S.J. [Advanced Biological and Environmental X-ray Facility, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 6-2100, Berkeley, CA 94720 (United States); Cramer, S.P. [Advanced Biological and Environmental X-ray Facility, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 6-2100, Berkeley, CA 94720 (United States); Biophysics Group, University of California, 1 Shields Avenue, EU-III, Davis, CA 95616 (United States)

2007-11-11

We have built a 36-pixel superconducting tunnel junction X-ray spectrometer for chemical analysis of dilute samples in the soft X-ray band. It offers an energy resolution of {approx}10-20 eV FWHM below 1 keV, a solid angle coverage of {approx}10{sup -3}, and can be operated at total rates of up to {approx}10{sup 6} counts/s. Here, we describe the spectrometer performance in speciation measurements by fluorescence-detected X-ray absorption spectroscopy at the Advanced Biological and Environmental X-ray facility at the ALS synchrotron.

Anomalous scattering and isomorphous replacement in X-ray diffuse scattering holography

Czech Academy of Sciences Publication Activity Database

Kopecký, Miloš; Kub, Jiří; Busetto, E.; Lausi, A.; Fábry, Jan; Šourek, Zbyněk

2007-01-01

Roč. 204, č. 8 (2007), s. 2572-2577 ISSN 1862-6300 R&D Projects: GA AV ČR IAA100100529; GA MŠk LA 287 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z10100520 Keywords : x-ray difuse scattering * x-ray holography Subject RIV: BM - Solid Matter Physics ; Magnetism

Observation of parametric X-ray radiation in an anomalous diffraction region

Energy Technology Data Exchange (ETDEWEB)

Alexeyev, V.I., E-mail: vial@x4u.lebedev.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Eliseyev, A.N., E-mail: elisseev@pluton.lpi.troitsk.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Irribarra, E., E-mail: esteban.irribarra@epn.edu.ec [Escuela Politécnica Nacional, Ladrón de Guevara E11-253, Quito (Ecuador); Kishin, I.A., E-mail: ivan.kishin@mail.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Kubankin, A.S., E-mail: kubankin@bsu.edu.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Nazhmudinov, R.M., E-mail: fizeg@bk.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation)

2016-08-19

A new possibility to expand the energy region of diffraction processes based on the interaction of relativistic charged particles with crystalline structures is presented. Diffracted photons related to parametric X-ray radiation produced by relativistic electrons are detected below the low energy threshold for the X-ray diffraction mechanism in crystalline structures for the first time. The measurements were performed during the interaction of 7 MeV electrons with a textured polycrystalline tungsten foil and a highly oriented pyrolytic graphite crystal. The experiment results are in good agreement with a developed model based on the PXR kinematical theory. The developed experimental approach can be applied to separate the contributions of real and virtual photons to the total diffracted radiation generated during the interaction of relativistic charged particles with crystalline targets. - Highlights: • Parametric X-ray radiation below the low energy threshold for diffraction of free X-rays. • Experimental separation of the contributions from different radiation mechanisms. • PXR from relativistic electrons in mosaic crystals and textured polycrystlas.

Characterizing the X-ray Emission in Small Magellanic Cloud Supernova Remnants

Science.gov (United States)

Man, Nicole; Auchettl, Katie; Lopez, Laura

2018-01-01

The Small Magellanic Cloud is a close, metal-poor galaxy with active star formation, and it has a diverse population of 24 supernova remnants (SNRs) that have been identified at several wavelengths. Past work has characterized the X-ray emission in these sources separately and aimed to constrain their explosive origins from observations with Chandra and XMM-Newton. Three SNRs have possible evidence for Type Ia explosions based on strong Fe-L emission in their X-ray spectra, although the environments and intermediate-mass element abundances are more consistent with those of core-collapse SNe. In this poster, we analyze the archival Chandra and XMM-Newton observations of the SMC SNR sample, and we model the sources' X-ray spectra in a systematic way to derive the plasma properties and to constrain the nature of the explosions. In one SNR, we note the presence of an X-ray binary near the source's geometric center, suggesting the compact object was produced in the SN explosion. As one of only three SNRs known in the Local Group to host a binary system, this source is worthy of follow-up investigations to probe explosions of massive stars in binary systems.

Study of X-ray source based on a small marx generator

International Nuclear Information System (INIS)

Jia Wei; Li Junna; Chen Weiqing; Tang Junping; He Xiaoping

2014-01-01