Science.gov

Sample records for non-specular x-ray reflection

  1. Study of interface correlation in W/C multilayer structure by specular and non-specular grazing incidence X-ray reflectivity measurements

    SciTech Connect

    Biswas, A. Bhattacharyya, D.; Sahoo, N. K.; Maidul Haque, S.; Tripathi, S.; De, Rajnarayan; Rai, S.

    2015-10-28

    W/C/W tri-layer thin film samples have been deposited on c-Si substrates in a home-built Ion Beam Sputtering system at 1.5 × 10{sup −3} Torr Ar working pressure and 10 mA grid current. The tri-layer samples have been deposited at different Ar{sup +} ion energies between 0.6 and 1.2 keV for W layer deposition and the samples have been characterized by specular and non-specular grazing incidence X-ray reflectivity (GIXR) measurements. By analyzing the GIXR spectra, various interface parameters have been obtained for both W-on-C and C-on-W interfaces and optimum Ar{sup +} ion energy for obtaining interfaces with low imperfections has been found. Subsequently, multilayer W/C samples with 5-layer, 7-layer, 9-layer, and 13-layer have been deposited at this optimum Ar{sup +} ion energy. By fitting the specular and diffused GIXR data of the multilayer samples with the parameters of each interface as fitting variables, different interface parameters, viz., interface width, in-plane correlation length, interface roughness, and interface diffusion have been estimated for each interface and their variation across the depth of the multilayers have been obtained. The information would be useful in realizing W/C multilayers for soft X-ray mirror application in the <100 Å wavelength regime. The applicability of the “restart of the growth at the interface” model in the case of these ion beam sputter deposited W/C multilayers has also been investigated in the course of this study.

  2. X-ray Reflection

    NASA Astrophysics Data System (ADS)

    Fabian, A. C.; Ross, R. R.

    2010-12-01

    Material irradiated by X-rays produces backscattered radiation which is commonly known as the Reflection Spectrum. It consists of a structured continuum, due at high energies to the competition between photoelectric absorption and electron scattering enhanced at low energies by emission from the material itself, together with a complex line spectrum. We briefly review the history of X-ray reflection in astronomy and discuss various methods for computing the reflection spectrum from cold and ionized gas, illustrated with results from our own work reflionx. We discuss how the reflection spectrum can be used to obtain the geometry of the accretion flow, particularly the inner regions around black holes and neutron stars.

  3. Restoration of Scene Information Reflected from Non-Specular Media

    DTIC Science & Technology

    2011-03-01

    refraction, reflection, absorption, ordinary dispersion and diffraction, provided that there is no change in its refrangibility, and provided it does not...with the center of the object at the origin. This is the only coordinate system that changes with respect to any other coordinate system during the...all of the recorded data images. Furthermore, with a change of variables, Eq. (68) can be rewritten

  4. Evaluation of non-specular reflecting silvered Teflon and filled adhesives

    NASA Technical Reports Server (NTRS)

    Bourland, G.; Cox, R. L.

    1981-01-01

    A non-specular silver-Teflon tape thermal control coating was tested to provide the data necessary to qualify it for use on the Space Shuttle Orbiter radiators. Effects of cure cycle temperature and pressure on optical and mechanical properties on the silver-Teflon tape were evaluated. The baseline Permacel P-223 adhesive, used with the specular silver-Teflon tape initially qualified for the Orbiter radiators, and four alternate metal-filled and unfilled adhesives were evaluated. Tests showed the cure process has no effect on the silver-Teflon optical properties, and that the baseline adhesive cure cycle gives best results. In addition the P-223 adhesive bond is more reproducible than the alternates, and the non-specular tape meets both the mechanical and the optical requirements of the Orbiter radiator coating specification. Existing Orbiter coating techniques were demonstrated to be effective in aplying the non-specular tape to a curved panel simulating the radiators. Author

  5. X-ray induced optical reflectivity

    NASA Astrophysics Data System (ADS)

    Durbin, Stephen M.

    2012-12-01

    The change in optical reflectivity induced by intense x-ray pulses can now be used to study ultrafast many body responses in solids in the femtosecond time domain. X-ray absorption creates photoelectrons and core level holes subsequently filled by Auger or fluorescence processes, and these excitations ultimately add conduction and valence band carriers that perturb optical reflectivity. Optical absorption associated with band filling and band gap narrowing is shown to explain the basic features found in recent measurements on an insulator (silicon nitride, Si3N4), a semiconductor (gallium arsenide, GaAs), and a metal (gold, Au), obtained with ˜100 fs x-ray pulses at 500-2000 eV and probed with 800 nm laser pulses. In particular GaAs exhibits an abrupt drop in reflectivity, persisting only for a time comparable to the x-ray excitation pulse duration, consistent with prompt band gap narrowing.

  6. X-ray reflectivity and surface roughness

    SciTech Connect

    Ocko, B.M.

    1988-01-01

    Since the advent of high brightness synchrotron radiation sources there has been a phenomenal growth in the use of x-rays as a probe of surface structure. The technique of x-ray reflectivity is particularly relevant to electrochemists since it is capable of probing the structure normal to an electrode surface in situ. In this paper the theoretical framework for x-ray reflectivity is reviewed and the results from previous non-electrochemistry measurements are summarized. These measurements are from the liquid/air interface (CCl/sub 4/), the metal crystal vacuum interface (Au(100)), and from the liquid/solid interface(liquid crystal/silicon). 34 refs., 5 figs.

  7. Total external reflection of X-rays from solid surfaces

    NASA Astrophysics Data System (ADS)

    Stozharov, V. M.

    2017-01-01

    The reflection of X-rays from solid surfaces is comprehensively studied using the measurements of patterns of total external reflection and X-ray diffraction with the aid of a parabolic mirror. Principles for theoretical processing of X-ray patterns are developed. An inverse dependence of the refractive index of X-ray radiation on the interplanar distances in crystallites is obtained.

  8. Reflection soft X-ray microscope and method

    DOEpatents

    Suckewer, S.; Skinner, C.H.; Rosser, R.

    1993-01-05

    A reflection soft X-ray microscope is provided by generating soft X-ray beams, condensing the X-ray beams to strike a surface of an object at a predetermined angle, and focusing the X-ray beams reflected from the surface onto a detector, for recording an image of the surface or near surface features of the object under observation.

  9. Reflection soft X-ray microscope and method

    DOEpatents

    Suckewer, Szymon; Skinner, Charles H.; Rosser, Roy

    1993-01-01

    A reflection soft X-ray microscope is provided by generating soft X-ray beams, condensing the X-ray beams to strike a surface of an object at a predetermined angle, and focusing the X-ray beams reflected from the surface onto a detector, for recording an image of the surface or near surface features of the object under observation.

  10. Principles of femtosecond X-ray/optical cross-correlation with X-ray induced transient optical reflectivity in solids

    NASA Astrophysics Data System (ADS)

    Eckert, S.; Beye, M.; Pietzsch, A.; Quevedo, W.; Hantschmann, M.; Ochmann, M.; Ross, M.; Minitti, M. P.; Turner, J. J.; Moeller, S. P.; Schlotter, W. F.; Dakovski, G. L.; Khalil, M.; Huse, N.; Föhlisch, A.

    2015-02-01

    The discovery of ultrafast X-ray induced optical reflectivity changes enabled the development of X-ray/optical cross correlation techniques at X-ray free electron lasers worldwide. We have now linked through experiment and theory the fundamental excitation and relaxation steps with the transient optical properties in finite solid samples. Therefore, we gain a thorough interpretation and an optimized detection scheme of X-ray induced changes to the refractive index and the X-ray/optical cross correlation response.

  11. Principles of femtosecond X-ray/optical cross-correlation with X-ray induced transient optical reflectivity in solids

    SciTech Connect

    Eckert, S. E-mail: martin.beye@helmholtz-berlin.de; Beye, M. E-mail: martin.beye@helmholtz-berlin.de; Pietzsch, A.; Quevedo, W.; Hantschmann, M.; Ochmann, M.; Huse, N.; Ross, M.; Khalil, M.; Minitti, M. P.; Turner, J. J.; Moeller, S. P.; Schlotter, W. F.; Dakovski, G. L.; Föhlisch, A.

    2015-02-09

    The discovery of ultrafast X-ray induced optical reflectivity changes enabled the development of X-ray/optical cross correlation techniques at X-ray free electron lasers worldwide. We have now linked through experiment and theory the fundamental excitation and relaxation steps with the transient optical properties in finite solid samples. Therefore, we gain a thorough interpretation and an optimized detection scheme of X-ray induced changes to the refractive index and the X-ray/optical cross correlation response.

  12. Non-specular reflections in a macroscopic system with wave-particle duality: spiral waves in bounded media.

    PubMed

    Langham, Jacob; Barkley, Dwight

    2013-03-01

    Spiral waves in excitable media possess both wave-like and particle-like properties. When resonantly forced (forced at the spiral rotation frequency) spiral cores travel along straight trajectories, but may reflect from medium boundaries. Here, numerical simulations are used to study reflections from two types of boundaries. The first is a no-flux boundary which waves cannot cross, while the second is a step change in the medium excitability which waves do cross. Both small-core and large-core spirals are investigated. The predominant feature in all cases is that the reflected angle varies very little with incident angle for large ranges of incident angles. Comparisons are made to the theory of Biktashev and Holden. Large-core spirals exhibit other phenomena such as binding to boundaries. The dynamics of multiple reflections is briefly considered.

  13. Near-100 percent Bragg Reflectivity of X-rays

    SciTech Connect

    Y Shvydko; S Stoupin; V Blank; S Terentyev

    2011-12-31

    Ultrahigh-reflectance mirrors are essential optical elements of the most sophisticated optical instruments devised over the entire frequency spectrum. In the X-ray regime, super-polished mirrors with close to 100% reflectivity are routinely used at grazing angles of incidence. However, at large angles of incidence, and particularly at normal incidence, such high reflectivity has not yet been achieved. Here, we demonstrate by direct measurements that synthetic, nearly defect-free diamond crystals reflect more than 99% of hard X-ray photons backwards in Bragg diffraction, with a remarkably small variation in magnitude across the sample. This is a quantum leap in the largest reflectivity measured to date, which is at the limit of what is theoretically possible. This accomplishment is achieved under the most challenging conditions of normal incidence and with extremely hard X-ray photons.

  14. Resonant soft x-ray reflectivity of polymer bilayers

    NASA Astrophysics Data System (ADS)

    Wang, Cheng

    2005-03-01

    Hard x-ray reflectivity is a very successful and common tool to measure thin film thickness, roughness, and interfacial widths in bilayers. However, hard x-rays have low or even insufficient contrast for a number of polymer species. For this reason, neutron reflectivity is often used in which the contrast can be enhanced enormously by deuterating one species. Alternatively, x-ray reflectivity capabilities could be extended by enhancing the contrast between layers through resonant methods near absorption edges. We are in the process of evaluating if soft x- ray resonant reflectivity is a valuable complement to hard x-ray and neutron reflectivity. Measurements were performed on PS/PMMA and PS/P2VP bilayer structures near the carbon-1s and nitrogen-1s or oxygen 1s K absorption edges on samples with individual layer thicknesses of 10-40 nm. At these photon energies the scattering factors f1 and f2 can be varied substantially, amounting to ?turning on and off? PS and PMMA or P2VP selectively. Large differences in reflected intensity have indeed been observed as a function of photon energy in θ-2θ measurements. We are in the process of characterizing the intrinsic limitation of interfacial width measurements and the limitations on film thickness due the longer wavelength and lower penetration power of soft X-rays. - Data acquired at the X-ray Calibrations and Standards beamline 6.3.2 at the Advanced Light Source at the Berkeley National Laboratory. Research supported by U.S. DoE.

  15. Measurements of the hard-x-ray reflectivity of iridium

    SciTech Connect

    Romaine, S.; Bruni, R.; Gorenstein, P.; Zhong, Z

    2007-01-10

    In connection with the design of a hard-x-ray telescope for the Constellation X-Ray Observatory we measured the reflectivity of an iridium-coated zerodur substrate as a function of angle at 55, 60, 70, and 80 keV at the National Synchrotron Light Source of Brookhaven National Laboratory. The optical constants were derived from the reflectivity data. The real component of the index of refraction is in excellent agreement with theoretical values at all four energies. However, the imaginary component, which is related to the mass attenuation coefficient, is 50% to 70% larger at 55, 60, and 70 keV than theoretical values.

  16. X-ray reflectivity measurements of vacuum deposited thin films

    SciTech Connect

    Chason, M. ); Chason, E. )

    1992-01-01

    X-ray reflectivity using energy dispersive X-ray detection, a nondestructive probe of surface roughness over the region of [approximately] 1--50 [Angstrom], has been used to investigate the characteristicsof vacuum deposited thin films. With a surface roughness sensitivity better than 1 [Angstrom] X-ray reflectivity is sensitive to interfaces between different materials for sample thicknesses up to approximately2000 [Angstrom] (depending on material density). We have investigated discrete Cr/Al deposits on quartz substrates and determined the surface roughness at the interfaces. We have also monitored the evolution ofthe Cr/Al interface following annealing. The experimental data is presented and discussed. The use of the technique for studying thin film deposits is addressed.

  17. X-ray reflectivity measurements of vacuum deposited thin films

    SciTech Connect

    Chason, M.; Chason, E.

    1992-12-31

    X-ray reflectivity using energy dispersive X-ray detection, a nondestructive probe of surface roughness over the region of {approximately} 1--50 {Angstrom}, has been used to investigate the characteristicsof vacuum deposited thin films. With a surface roughness sensitivity better than 1 {Angstrom} X-ray reflectivity is sensitive to interfaces between different materials for sample thicknesses up to approximately2000 {Angstrom} (depending on material density). We have investigated discrete Cr/Al deposits on quartz substrates and determined the surface roughness at the interfaces. We have also monitored the evolution ofthe Cr/Al interface following annealing. The experimental data is presented and discussed. The use of the technique for studying thin film deposits is addressed.

  18. Lensless x-ray imaging in reflection geometry

    SciTech Connect

    Roy, S.; Parks, D.H.; Seu, K.A.; Turner, J.J.; Chao, W.; Anderson, E.H.; Cabrini, S.; Kevan, S.D.; Su, R.

    2011-02-03

    Lensless X-ray imaging techniques such as coherent diffraction imaging and ptychography, and Fourier transform holography can provide time-resolved, diffraction-limited images. Nearly all examples of these techniques have focused on transmission geometry, restricting the samples and reciprocal spaces that can be investigated. We report a lensless X-ray technique developed for imaging in Bragg and small-angle scattering geometries, which may also find application in transmission geometries. We demonstrate this by imaging a nanofabricated pseudorandom binary structure in small-angle reflection geometry. The technique can be used with extended objects, places no restriction on sample size, and requires no additional sample masking. The realization of X-ray lensless imaging in reflection geometry opens up the possibility of single-shot imaging of surfaces in thin films, buried interfaces in magnetic multilayers, organic photovoltaic and field-effect transistor devices, or Bragg planes in a single crystal.

  19. X-ray Reflection Gratings: Technology Development Status Update

    NASA Astrophysics Data System (ADS)

    McEntaffer, Randall L.

    2016-04-01

    We present the current status in the development of X-ray reflection gratings. Gratings mounted in the off-plane configuration are capable of achieving high spectral resolving power concurrently with high diffraction efficiency. This will enable key soft X-ray spectroscopy science goals to be achieved. We have identified hurdles to practically achieving the theoretical performance goals. Here we present our methodologies to overcome these challenges. Furthermore, we discuss how we test these methods to quantify performance capabilities. The results of these tests are placed in the context of Technology Readiness Level (TRL) in order to demonstrate our current status and to discuss our plans for the future.

  20. Relativistic Effects on Reflection X-ray Spectra of AGN

    SciTech Connect

    Lee, Khee-Gan; Fuerst, Steven V.; Brandwardi-Raymond, Graziella; Wu, Kinwah; Crowley, Oliver; /University Coll. London

    2007-01-05

    We have calculated the reflection component of the X-ray spectra of active galactic nuclei (AGN) and shown that they can be significantly modified by the relativistic motion of the accretion flow and various gravitational effects of the central black hole. The absorption edges in the reflection spectra suffer severe energy shifts and smearing. The degree of distortion depends on the system parameters, and the dependence is stronger for some parameters such as the inner radius of the accretion disk and the disk viewing inclination angles. The relativistic effects are significant and are observable. Improper treatment of the reflection component of the X-ray continuum in spectral fittings will give rise to spurious line-like features, which will mimic the fluorescent emission lines and mask the relativistic signatures of the lines.

  1. The theoretical reflectance of X-rays from optical surfaces

    NASA Technical Reports Server (NTRS)

    Neergaard, J. R.; Reynolds, J. M.; Fields, S. A.

    1976-01-01

    The theoretical reflectance of X-rays from various materials and evaporated films is presented. A computer program was written that computes the reflected intensity as a function of the angle of the incident radiation. The quantities necessary to generate the efficiency and their effect on the data are demonstrated. Five materials were chosen for evaluation: (1) fused silica, (2) chromium, (3) beryllium, (4) gold, and (5) a thin layer contaminant. Fused silica is a versatile and common material; chromium has high reflection efficiency at X-ray wavelengths and is in the middle of the atomic number range; beryllium contains a single atomic shell and has a low range atomic number; gold contains multiple atomic shells and has a high atomic number; the contaminant is treated as a thin film in the calculations and results are given as a function of thickness for selected wavelengths. The theoretical results are compared to experimental data at lambda = 8.34 A.

  2. Anisotropic x-ray anomalous diffraction and forbidden reflections

    SciTech Connect

    Carra, P.; Thole, B.T. )

    1994-10-01

    In this paper the authors present a general analysis of resonant elastic scattering of x rays. The approach exploits crystal symmetry, scattering geometry, and polarization. Extinction rules, their breaking, and the observation of forbidden reflections are discussed. As an application, a detailed description of the experiment performed by Finkelstein, Shen, and Shastri at the iron [ital K] edge in [alpha] Fe[sub 2]O[sub 3] (hematite) is reported.

  3. Progress in reflection grating spectrometers for X-ray astrophysics

    NASA Astrophysics Data System (ADS)

    McEntaffer, Randall L.

    2017-08-01

    Soft X-ray spectroscopy can address future science goals pertaining to understanding the cycle of hot baryons in the universe. Detailing feedback processes in galaxies, mapping the distribution of baryons in the circum- and intergalactic medium, and unraveling unknowns in stellar life cycles places demanding requirements upon spectrometers. Here, we detail advancements in reflection grating technologies that can be used to help provide answers to these important questions. We also discuss possible applications including a configuration for the Lynx concept strategic mission.

  4. Backscatter of hard X-rays in the solar atmosphere. [Calculating the reflectance of solar x ray emission

    NASA Technical Reports Server (NTRS)

    Bai, T.; Ramaty, R.

    1977-01-01

    The solar photosphere backscatters a substantial fraction of the hard X rays from solar flares incident upon it. This reflection was studied using a Monte Carlo simulation which takes into account Compton scattering and photo-electric absorption. Both isotropic and anisotropic X ray sources are considered. The bremsstrahlung from an anisotropic distribution of electrons are evaluated. By taking the reflection into account, the inconsistency is removed between recent observational data regarding the center-to-limb variation of solar X ray emission and the predictions of models in which accelerated electrons are moving down toward the photosphere.

  5. Modern approaches to investigation of thin films and monolayers: X-ray reflectivity, grazing-incidence X-ray scattering and X-ray standing waves

    NASA Astrophysics Data System (ADS)

    Shcherbina, M. A.; Chvalun, S. N.; Ponomarenko, S. A.; Kovalchuk, M. V.

    2014-12-01

    The review concerns modern experimental methods of structure determination of thin films of different nature. The methods are based on total reflection of X-rays from the surface and include X-ray reflectivity, grazing-incidence X-ray scattering and X-ray standing waves. Their potential is exemplified by the investigations of various organic macromolecular systems that exhibit the properties of semiconductors and are thought to be promising as thin-film transistors, light-emitting diodes and photovoltaic cells. It is shown that combination of the title methods enable high-precision investigations of the structure of thin-film materials and structure formation in them, i.e., it is possible to obtain information necessary for improvement of the operating efficiency of elements of organic electronic devices. The bibliography includes 92 references.

  6. Reflection of attosecond x-ray free electron laser pulses

    SciTech Connect

    Hau-Riege, S; Chapman, H

    2006-10-30

    In order to utilize hard x-ray free electron lasers (XFEL's) when they are extended to attosecond pulse lengths, it is necessary to choose optical elements with minimal response time. Specular grazing incidence optics made of low-Z materials are popular candidates for reflectors since they are likely to withstand x-ray damage and provide sufficiently large reflectivities. Using linear-optics reflection theory, we calculated the transient reflectivity of a delta-function electric pulse from a homogeneous semi-infinite medium as a function of angle of incidence for s- and p-polarized light. We specifically considered the pulse response of Be, diamond, silicon carbide, and silicon, all of which are of relevance to the XFEL's that are currently being built. We found that the media emit energy in a damped oscillatory way, and that the impulse-response times are shorter than 0.3 fs for normal incidence. For grazing incidence, the impulse-response time is substantially shorter, making grazing-incidence mirrors a good choice for deep-sub-femtosecond reflective optics.

  7. Reflection of attosecond x-ray free electron laser pulses

    SciTech Connect

    Hau-Riege, Stefan P.; Chapman, Henry N.

    2007-01-15

    In order to utilize hard x-ray free electron lasers (XFEL's) when they are extended to attosecond pulse lengths, it is necessary to choose optical elements with minimal response time. Specular grazing-incidence optics made of low-Z materials are popular candidates for reflectors since they are likely to withstand x-ray damage and provide sufficiently large reflectivities. Using linear-optics reflection theory, we calculated the transient reflectivity of a delta-function electric pulse from a homogenous semi-infinite medium as a function of angle of incidence for s- and p-polarized light. We specifically considered the pulse response of beryllium, diamond, silicon carbide, and silicon, all of which are of relevance to the XFEL's that are currently being built. We found that the media emit energy in a damped oscillatory way, and that the impulse-response times are shorter than 0.3 fs for normal incidence. For grazing incidence, the impulse-response time is substantially shorter, making grazing-incidence mirrors a good choice for deep subfemtosecond reflective optics.

  8. Ultra Low-{kappa} Metrology Using X-Ray Reflectivity And Small-Angle X-Ray Scattering Techniques

    SciTech Connect

    Plantier, L.; Gonchond, J.-P.; Pernot, F.; Peled, A.; Yokhin, B.; Wyon, C.; Royer, J.-C.

    2007-09-26

    The automated metrology tool, combining X-ray reflectivity XRR and small-angle X-ray scattering SAXS has been demonstrated as a capable equipment to assess standard porous Ultra low-{kappa} (ULK) metrology. Therefore those techniques have enabled characterizations of several ULK used in sub-65 nm nodes integration. Standard ULK material for 65 nm node technology has been monitored through the whole C065 integration steps using those combined techniques.

  9. Reflective Coating for Lightweight X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Chan, Kai-Wing; Zhang, William W.; Windt, David; Hong, Mao-Ling; Saha, Timo; McClelland, Ryan; Sharpe, Marton; Dwivedi, Vivek H.

    2012-01-01

    X-ray reflective coating for next generation's lightweight, high resolution, optics for astronomy requires thin-film deposition that is precisely fine-tuned so that it will not distort the thin sub-mm substrates. Film of very low stress is required. Alternatively, mirror distortion can be cancelled by precisely balancing the deformation from multiple films. We will present results on metallic film deposition for the lightweight optics under development. These efforts include: low-stress deposition by magnetron sputtering and atomic layer deposition of the metals, balancing of gross deformation with two-layer depositions of opposite stresses and with depositions on both sides of the thin mirrors.

  10. Shock-reflected electrons and X-ray line spectra

    NASA Astrophysics Data System (ADS)

    Dzifčáková, E.; Vandas, M.; Karlický, M.

    2017-07-01

    Aims: The aim of this paper is to try to explain the physical origin of the non-thermal electron distribution that is able to form the enhanced intensities of satellite lines in the X-ray line spectra observed during the impulsive phases of some solar flares. Methods: Synthetic X-ray line spectra of the distributions composed of the distribution of shock reflected electrons and the background Maxwellian distribution are calculated in the approximation of non-Maxwellian ionization, recombination, excitation and de-excitation rates. The distribution of shock reflected electrons is determined analytically. Results: We found that the distribution of electrons reflected at the nearly-perpendicular shock resembles, at its high-energy part, the so called n-distribution. Therefore it could be able to explain the enhanced intensities of Si xiid satellite lines. However, in the region immediately in front of the shock its effect is small because electrons in background Maxwellian plasma are much more numerous there. Therefore, we propose a model in which the shock reflected electrons propagate to regions with smaller densities and different temperatures. Combining the distribution of the shock-reflected electrons with the Maxwellian distribution having different densities and temperatures we found that spectra with enhanced intensities of the satellite lines are formed at low densities and temperatures of the background plasma when the combined distribution is very similar to the n-distribution also in its low-energy part. In these cases, the distribution of the shock-reflected electrons controls the intensity ratio of the allowed Si xiii and Si xiv lines to the Si xiid satellite lines. The high electron densities of the background plasma reduce the effect of shock-reflected electrons on the composed electron distribution function, which leads to the Maxwellian spectra.

  11. Specular Reflection of Neutrons and X-Rays from Interfaces.

    NASA Astrophysics Data System (ADS)

    Willatt, Alison J.

    Available from UMI in association with The British Library. Requires signed TDF. The two new techniques of X-ray and neutron specular reflection have been applied to the study of adsorption at the liquid-vapour interface for the first time. Since the possibilities of using these techniques had hardly been considered at the start of the work, the potential of the techniques has also been extensively investigated by simulation. Experimental results have been obtained from three different interfacial systems. The thickness of the wetting layer in the methanol/cyclohexane system has been investigated, although it was found that it was difficult to achieve equilibrium with this system. The neutron reflectivity from a Newton black soap film has been analysed to give the first direct measurement of the thickness of the aqueous core (20 A). The neutron reflectivity from a butyl arachidate monolayer, spread on water, has been measured over a range of surface pressures. The presence of an adsorbed layer was readily detected on the gravity mirror and the reflectivity was enhanced as the density of the monolayer was increased. However, at such low values of momentum transfer, it was not possible to determine the film thickness. The thickness of the monolayer was determined from X-ray reflectivity measurements over a wide range of scattering vectors. The overall thickness of 30 A is consistent with the molecules being orientated close to perpendicular to the surface, with the butyl chain penetrating the subphase. The complexities of methods hitherto used to calculate reflectivity profiles have made it difficult to assess the best way of utilizing reflection most effectively. A simpler, approximate, model has been used in a range of simulations to show how contrast variation is best used and as a means of assessing suitable graphical methods for analysing experimental data.

  12. X-ray natural birefringence in reflection from graphene

    NASA Astrophysics Data System (ADS)

    Jansing, C.; Mertins, H.-Ch.; Gilbert, M.; Wahab, H.; Timmers, H.; Choi, S.-H.; Gaupp, A.; Krivenkov, M.; Varykhalov, A.; Rader, O.; Legut, D.; Oppeneer, P. M.

    2016-07-01

    The existence of natural birefringence in x-ray reflection on graphene is demonstrated at energies spanning the carbon 1 s absorption edge. This new x-ray effect has been discovered with precision measurements of the polarization-plane rotation and the polarization-ellipticity changes that occur upon reflection of linearly polarized synchrotron radiation on monolayer graphene. Extraordinarily large polarization-plane rotations of up to 30∘, accompanied by a change from linearly to circularly polarized radiation have been measured for graphene on copper. Graphene on single crystalline cobalt, grown on tungsten, exhibits rotation values of up to 17∘. Both graphene systems show resonantly enhanced effects at the π* and σ* energies. The results are referenced against those obtained for polycrystalline carbon and highly oriented pyrolytic graphite (HOPG), respectively. As expected, polycrystalline carbon shows negligible rotation, whereas a huge maximum rotation of 140∘ has been observed for HOPG that may be considered a graphene multilayer system. HOPG is found to exhibit such large rotation values over a broad energy range, even well beyond the π* resonance energy due to the contributions of numerous graphene layers. To explain the origin of the observed natural birefringence of graphene, the Stokes parameters as well as the x-ray natural linear dichroism in reflection have been determined. It is shown that the birefringence directly results from the optical anisotropy related to the orthogonal alignment of π* and σ* bonds in the graphene layer. Our polarization analysis reveals a strong bonding of graphene on Co with a reduced σ* excitation energy and a strong tilt of 50 % of the pz orbitals towards diagonal orientation. In contrast, graphene on Cu is weakly bound with an orthogonal orientation of the pz orbitals. Exhibiting such a large natural birefringence that can be controlled through substrate choice, and because of excellent heat conductivity

  13. X-ray microscopy using grazing-incidence reflections optics

    SciTech Connect

    Price, R.H.

    1983-06-30

    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.

  14. X-ray microscopy using grazing-incidence reflection optics

    SciTech Connect

    Price, R.H.

    1981-08-06

    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.

  15. An experimental measurement of metal multilayer x-ray reflectivity degradation due to intense x-ray flux

    SciTech Connect

    Hockaday, M.Y.P.

    1987-06-01

    The degradation of the x-ray reflection characteristics of metal multilayer Bragg diffractors due to intense x-ray flux was investigated. The Z-pinch plasma produced by PROTO II of Sandia National Laboratories, Albuquerque, New Mexico, was used as the source. The plasma generated total x-ray yields of as much as 40 kJ with up to 15 kJ in the neon hydrogen- and helium-like resonance lines in nominal 20-ns pulses. Molybdenum-carbon, palladium-carbon, and tungsten-carbon metal multilayers were placed at 15 and 150 cm from the plasma center. The multilayers were at nominal angles of 5/sup 0/ and 10/sup 0/ to diffract the neon resonance lines. The time-integrated x-ray reflection of the metal multilayers was monitored by x-ray film. A fluorescer-fiber optic-visible streak camera detector system was then used to monitor the time-resolved x-ray reflection characteristics of 135 A- 2d tungsten-carbon multilayers. A large specular component in the reflectivity prevented determination of the rocking curve of the multilayer. For a neon implosion onto a vanadium-doped polyacrylic acid foam target shot, detailed modeling was attempted. The spectral flux was determined with data from 5 XRD channels and deconvolved using the code SHAZAM. The observed decay in reflectivity was assumed to correspond to the melting of the first tungsten layer. A ''conduction factor'' of 82 was required to manipulate the heat loading of the first tungsten layer such that the time of melting corresponded to the observed decay. The power at destruction was 141 MW/cm/sup 2/ and the integrated energy at destruction was 2.0 J/cm/sup 2/. 82 refs., 66 figs., 10 tabs.

  16. Quo Vadis total reflection X-ray fluorescence?

    NASA Astrophysics Data System (ADS)

    Pahlke, Siegfried

    2003-12-01

    The multielement trace analytical method 'total reflection X-ray fluorescence' (TXRF) has become a successfully established method in the semiconductor industry, particularly, in the ultra trace element analysis of silicon wafer surfaces. TXRF applications can fulfill general industrial requirements on daily routine of monitoring wafer cleanliness up to 300 mm diameter under cleanroom conditions. Nowadays, TXRF and hyphenated TXRF methods such as 'vapor phase decomposition (VPD)-TXRF', i.e. TXRF with a preceding surface and acid digestion and preconcentration procedure, are automated routine techniques ('wafer surface preparation system', WSPS). A linear range from 10 8 to 10 14 [atoms/cm 2] for some elements is regularly controlled. Instrument uptime is higher than 90%. The method is not tedious and can automatically be operated for 24 h/7 days. Elements such as S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Sn, Sb, Ba and Pb are included in the software for standard peak search. The detection limits of recovered elements are between 1×10 11 and 1×10 7 [atoms/cm 2] depending upon X-ray excitation energy and the element of interest. For the determination of low Z elements, i.e. Na, Al and Mg, TXRF has also been extended but its implementation for routine analysis needs further research. At present, VPD-TXRF determination of light elements is viable in a range of 10 9 [atoms/cm 2]. Novel detectors such as silicon drift detectors (SDD) with an active area of 5 mm 2, 10 mm 2 or 20 mm 2, respectively, and multi-array detectors forming up to 70 mm 2 are commercially available. The first SDD with 100 mm 2 (!) area and integrated backside FET is working under laboratory conditions. Applications of and comparison with ICP-MS, HR-ICP-MS and SR-TXRF, an extension of TXRF capabilities with an extremely powerful energy source, are also reported.

  17. Hydration structure of the barite (001)–water interface: Comparison of x-ray reflectivity with molecular dynamics simulations

    DOE PAGES

    Bracco, Jacquelyn N.; Lee, Sang Soo; Stubbs, Joanne E.; ...

    2017-05-11

    The three-dimensional structure of the barite (001)-water interface was studied using in situ specular and non-specular X-ray reflectivity (XR). Displacements of the barium and sulfate ions in the surface of a barite crystal and the interfacial water structure were defined in the analyses. The largest relaxations (0.13 Å lateral and 0.08 Å vertical) were observed for the barium and sulfate ions in the topmost unit cell layer, which diminished rapidly with depth. The best fit structure identified four distinct adsorbed species, which in comparison with molecular dynamics (MD) simulations, reveals that they are associated with positions of adsorbed water, eachmore » of which coordinates one or two surface ions (either barium, sulfate, or both). These water molecules also adsorb in positions consistent with those of bariums and sulfates in the bulk crystal lattice. These results demonstrate the importance of combining high resolution XR with MD simulations to fully describe the atomic structure of the hydrated mineral surface. As a result, the agreement between the results indicates both the uniqueness of the structural model obtained from the XR analysis and the accuracy of the force field used in the simulations.« less

  18. A Experimental Measurement of Metal Multilayer X-Ray Reflectivity Degradation due to Intense X-Ray Flux.

    NASA Astrophysics Data System (ADS)

    Hockaday, Mary Yvonne Pottenger

    The degradation of the x-ray reflection characteristics of metal multilayer Bragg diffractors due to intense x -ray flux was investigated. The Z-pinch plasma produced by PROTO II of Sandia National Laboratories, Albuquerque, New Mexico, was used as the source. The plasma generated total x-ray yields of as much as 40 kJ with up to 15 kJ in the neon hydrogen- and helium-like resonance lines in nominal 20-ns pulses. Molybdenum-carbon, paladium-carbon, and tungsten -carbon metal multilayers were placed at 15 and 150 cm from the plasma center. The multilayers were at nominal angles of 5(DEGREES) and 10(DEGREES) to diffract the neon resonance lines. The time-integrated x-ray reflection of the metal multilayers was monitored by x-ray film. A fluorescer -fiber optic-visible streak camera detector system was then used to monitor the time-resolved x-ray reflection characteristics of 135 (ANGSTROM)- 2d tungsten-carbon multilayers. A large specular component in the reflectivity prevented determination of the rocking curve of the multilayer. Data for two separate shots were analyzed. For a pure neon gas shot at a power level of 420 TW, the reflectivity of the multilayer at 15 cm decayed rapidly with respect to the still-rising signal of the multilayer at 150 cm. The onset time of the decay corresponded to an integrated dose of 5.27 J/cm('2). For a neon implosion onto a vanadium-doped polyacrylic acid foam target shot, detailed modeling was attempted. The spectral flux was determined with data from 5 XRD channels and deconvolved using the code SHAZAM. The observed decay in reflectivity was assumed to correspond to the melting of the first tungsten layer. A "conduction factor" of 82 was required to manipulate the heat loading of the first tungsten layer such that the time of melting corresponded to the observed decay. The power at destruction was 141 MW/cm('2) and the integrated energy at destruction was 2.0 J/cm('2).

  19. Grazing incidence X-ray reflectivity of gold and iridium coated flat mirrors

    NASA Astrophysics Data System (ADS)

    Aschenbach, Bernd; Braeuninger, Heinrich; Burkert, Wolfgang

    In the context of developing high reflectivity coatings for X-ray telescopes highly polished Zerodur and BK-7 glass flats have been coated with either gold or iridium. Grazing incidence reflectivity measurements at various X-ray energies are reported and compared with standard theory prediction.

  20. High-reflectivity High-resolution X-ray Crystal Optics with Diamonds

    SciTech Connect

    Shvyd’ko, Y.; Stoupin, S; Cunsolo, A; Said, A; Huang, X

    2010-01-01

    Owing to the depth to which hard X-rays penetrate into most materials, it is commonly accepted that the only way to realize hard-X-ray mirrors with near 100% reflectance is under conditions of total external reflection at grazing incidence to a surface. At angles away from grazing incidence, substantial reflectance of hard X-rays occurs only as a result of constructive interference of the waves scattered from periodically ordered atomic planes in crystals (Bragg diffraction). Theory predicts that even at normal incidence the reflection of X-rays from diamond under the Bragg condition should approach 100% - substantially higher than from any other crystal. Here we demonstrate that commercially produced synthetic diamond crystals do indeed show an unprecedented reflecting power at normal incidence and millielectronvolt-narrow reflection bandwidths for hard X-rays. Bragg diffraction measurements of reflectivity and the energy bandwidth show remarkable agreement with theory. Such properties are valuable to the development of hard-X-ray optics, and could greatly assist the realization of fully coherent X-ray sources, such as X-ray free-electron laser oscillators.

  1. Grating-based at-wavelength metrology of hard x-ray reflective optics.

    PubMed

    Berujon, Sebastien; Ziegler, Eric

    2012-11-01

    A mean of characterizing the tangential shape of a hard x-ray mirror is presented. Derived from a group of methods operating under visible light, its application in the x-ray domain using an x-ray absorption grating allows recovery of the mirror shape with nanometer accuracy and submillimeter spatial resolution. The method works with incoherent light, does not require any a priori information about the mirror characteristics and allows shape reconstruction of x-ray reflective optics under thermal and mechanical working conditions.

  2. (Synchrotron studies of x-ray reflectivity from surfaces)

    SciTech Connect

    Pershan, P.S.

    1992-03-03

    Following a long period of theoretical interest, but only limited measurements, there has recently been an increased number of attempts to expand the relative paucity of experimental information on the structure of liquid surfaces using techniques as diverse as ellipsometry, micro-force balances, non-linear optics, Auger and photoelectron spectroscopy, and x-ray scattering. Our group has played a leading role in the currently expanding application of scattering techniques to the general problem of characterizing the microscopic structure of liquid surfaces and we propose here that this work be extended specifically to liquid metals. In the following sections we will briefly describe the salient features of x-ray scattering that are relevant to the current project, the progress that we have made in the current grant period and the work that we propose to carry out in the forthcoming grant period.

  3. An experimental measurement of metal multilayer X-ray reflectivity degradation due to intense X-ray flux

    NASA Astrophysics Data System (ADS)

    Hockaday, Mary Yvonne Pottenger

    1987-06-01

    The degradation of the X-ray reflection characteristics of metal multilayer Bragg diffractors due to intense X-ray flux was investigated. Molybdenum-carbon, paladium-carbon, and tungsten-carbon metal multilayers were used. Data for two separate shots were analyzed. For a pure neon gas shot at 420 TW, the reflectivity of the multilayer at 15 cm decayed rapidly with respect to the still-rising signal of the multilayer at 150 cm. The onset time of the decay corresponded to an integrated dose of 5.27 J/sq cm. For a neon implosion onto a vanadium-doped polyacrylic acid foam target shot, detailed modeling was attempted. The spectral flux was determined with data from 5 XRD channels and deconvolved using the code SHAZAM. The observed decay in reflectivity was assumed to correspond to the melting of the first tungsten layer. A conduction factor of 8.9 was required to manipulate the heat loading of the first tungsten layer such that the time of melting corresponded to the observed decay. The power at destruction was 141 MW/sq cm and the integrated energy at destruction was 2.0 J/sq cm.

  4. X-ray resonant reflection from magnetic multilayers: Recursion matrix algorithm

    SciTech Connect

    Stepanov, S. A.; Sinha, S. K.

    2000-06-01

    Recursion equations for 2x2 scattering matrices have been derived to calculate resonant x-ray reflection from magnetic multilayers. The solution has been basically reduced to that found in Stepanov et al, Phys. Rev. B 57, 4829 (1998) for grazing incidence x-ray diffraction from crystalline multilayers. (c) 2000 The American Physical Society.

  5. CMP Control of Multi-Layer Inter-Layer Dielectrics (ILD) using X-ray Reflectivity

    SciTech Connect

    Bryant, Ross E.; Porter, Hethel; Gallegos, Jesus; O'Dell, Jeremy; Agnihotri, Dileep

    2007-09-26

    Thin sacrificial films are used as cap layer in the back-end semiconductor processing for protecting the bulk porous inter-layer low-k dielectric during the CMP process. The existing optical measurement techniques struggle to separate these thin films from the bulk low-k due to very similar optical coefficients. Glancing angle x-ray reflectivity is well suited for separation of thin sacrificial film and bulk dielectric film as x-ray reflectivity depends strongly on changes in electron densities for two materials. This paper discusses the x-ray reflectivity technique and its applications for measurement of low-k stack and sacrificial oxide post CMP.

  6. Temporal cross-correlation of x-ray free electron and optical lasers using soft x-ray pulse induced transient reflectivity.

    PubMed

    Krupin, O; Trigo, M; Schlotter, W F; Beye, M; Sorgenfrei, F; Turner, J J; Reis, D A; Gerken, N; Lee, S; Lee, W S; Hays, G; Acremann, Y; Abbey, B; Coffee, R; Messerschmidt, M; Hau-Riege, S P; Lapertot, G; Lüning, J; Heimann, P; Soufli, R; Fernández-Perea, M; Rowen, M; Holmes, M; Molodtsov, S L; Föhlisch, A; Wurth, W

    2012-05-07

    The recent development of x-ray free electron lasers providing coherent, femtosecond-long pulses of high brilliance and variable energy opens new areas of scientific research in a variety of disciplines such as physics, chemistry, and biology. Pump-probe experimental techniques which observe the temporal evolution of systems after optical or x-ray pulse excitation are one of the main experimental schemes currently in use for ultrafast studies. The key challenge in these experiments is to reliably achieve temporal and spatial overlap of the x-ray and optical pulses. Here we present measurements of the x-ray pulse induced transient change of optical reflectivity from a variety of materials covering the soft x-ray photon energy range from 500eV to 2000eV and outline the use of this technique to establish and characterize temporal synchronization of the optical-laser and FEL x-ray pulses.

  7. X-ray phase imaging with a laboratory source using selective reflection from a mirror.

    PubMed

    Pelliccia, Daniele; Paganin, David M

    2013-04-22

    A novel approach for hard x-ray phase contrast imaging with a laboratory source is reported. The technique is based on total external reflection from the edge of a mirror, aligned to intercept only half of the incident beam. The mirror edge thus produces two beams. The refraction x-rays undergo when interacting with a sample placed before the mirror, causes relative intensity variations between direct and reflected beams. Quantitative phase contrast and pure absorption imaging are demonstrated using this method.

  8. Forensic application of total reflection X-ray fluorescence spectrometry for elemental characterization of ink samples

    NASA Astrophysics Data System (ADS)

    Dhara, Sangita; Misra, N. L.; Maind, S. D.; Kumar, Sanjukta A.; Chattopadhyay, N.; Aggarwal, S. K.

    2010-02-01

    The possibility of applying Total Reflection X-ray Fluorescence for qualitative and quantitative differentiation of documents printed with rare earth tagged and untagged inks has been explored in this paper. For qualitative differentiation, a very small amount of ink was loosened from the printed documents by smoothly rubbing with a new clean blade without destroying the manuscript. 50 μL of Milli-Q water was put on this loose powder, on the manuscript, and was agitated by sucking and releasing the suspension two to three times with the help of a micropipette. The resultant dispersion was deposited on quartz sample support for Total Reflection X-ray Fluorescence measurements. The Total Reflection X-ray Fluorescence spectrum of tagged and untagged inks could be clearly differentiated. In order to see the applicability of Total Reflection X-ray Fluorescence for quantitative determinations of rare earths and also to countercheck such determinations in ink samples, the amounts of rare earth in painted papers with single rare earth tagged inks were determined by digesting the painted paper in HNO 3/HClO 4, mixing this solution with the internal standard and recording their Total Reflection X-ray Fluorescence spectra after calibration of the instrument. The results thus obtained were compared with those obtained by Inductively Coupled Plasma Mass Spectrometry and were found in good agreement. The average precision of the Total Reflection X-ray Fluorescence determinations was 5.5% (1 σ) and the average deviation of Total Reflection X-ray Fluorescence determined values with that of Inductively Coupled Plasma Mass Spectrometry was 7.3%. These studies have shown that Total Reflection X-ray Fluorescence offers a promising and potential application in forensic work of this nature.

  9. Efficient focusing of hard x rays to 25 nm by a total reflection mirror

    SciTech Connect

    Mimura, Hidekazu; Yumoto, Hirokatsu; Matsuyama, Satoshi; Sano, Yasuhisa; Yamamura, Kazuya; Mori, Yuzo; Yabashi, Makina; Nishino, Yoshinori; Tamasaku, Kenji; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2007-01-29

    Nanofocused x rays are indispensable because they can provide high spatial resolution and high sensitivity for x-ray nanoscopy/spectroscopy. A focusing system using total reflection mirrors is one of the most promising methods for producing nanofocused x rays due to its high efficiency and energy-tunable focusing. The authors have developed a fabrication system for hard x-ray mirrors by developing elastic emission machining, microstitching interferometry, and relative angle determinable stitching interferometry. By using an ultraprecisely figured mirror, they realized hard x-ray line focusing with a beam width of 25 nm at 15 keV. The focusing test was performed at the 1-km-long beamline of SPring-8.

  10. Monte Carlo simulation applied in total reflection x-ray fluorescence: Preliminary results

    SciTech Connect

    Meira, Luiza L. C.; Inocente, Guilherme F.; Vieira, Leticia D.; Mesa, Joel

    2013-05-06

    The X-ray Fluorescence (XRF) analysis is a technique for the qualitative and quantitative determination of chemical constituents in a sample. This method is based on detection of the characteristic radiation intensities emitted by the elements of the sample, when properly excited. A variant of this technique is the Total Reflection X-ray Fluorescence (TXRF) that utilizes electromagnetic radiation as excitation source. In total reflection of X-ray, the angle of refraction of the incident beam tends to zero and the refracted beam is tangent to the sample support interface. Thus, there is a minimum angle of incidence at which no refracted beam exists and all incident radiation undergoes total reflection. In this study, we evaluated the influence of the energy variation of the beam of incident x-rays, using the MCNPX code (Monte Carlo NParticle) based on Monte Carlo method.

  11. Ultra high throughput four-reflection x-ray telescope for high resolution spectroscopy

    NASA Astrophysics Data System (ADS)

    Tawara, Yuzuru; Mitsuishi, Ikuyuki; Babazaki, Yasunori; Nakamichi, Ren; Bandai, Ayako

    2015-09-01

    The first application of four-times reflection X-ray optics is planned for the DIOS mission, in which very soft X-ray observation is expected. On the other hand, effective area of the telescope for higher X-ray energy (E < 10 keV) including iron K emission lines has been so far limited to about 1000 cm2 for assumed several meter focal length. However, if we introduce four-reflection optics to this energy range, we can get several times large effective area for single telescope with same several meter focal length. To prove this possibility, we performed ray tracing simulation for four-reflection telescope with 6 m focal length and found that effective area of 3100 cm2 at 6 keV can be obtained for single telescope. In this paper, we will discuss about other telescope performances, mechanical properties and application to fine spectroscopic mission using X-ray micro-calorimeter.

  12. On Compton reflection in the sources of the cosmic X-ray background

    NASA Technical Reports Server (NTRS)

    Zdziarski, Andrzej A.; Zycki, Piotr T.; Svensson, Roland; Boldt, Elihu

    1993-01-01

    Consideration is given to recent models for the cosmic X-ray background that assume that it originates from unresolved AGN emitting spectra due to enhanced Compton reflection of a power-law photon spectrum incident on cold matter. The parameter space of the Compton reflection model is studied, and the allowed parameter space is found to be severely constrained by physical and cosmological effects. For an incident power-law energy index alpha is greater than about 1, the X-ray peak in the observed spectrum from a population of AGN is necessarily at an energy less than that of the observed peak. Two examples of improved fits to the X-ray background are shown. It is concluded that the Compton reflection models proposed to date do not provide a straightforward explanation of the X-ray background spectrum.

  13. Molecular orientation in soft matter thin films studied by resonant soft X-ray reflectivity

    SciTech Connect

    Mezger, Markus; Jerome, Blandine; Kortright, Jeffrey B.; Valvidares, Manuel; Gullikson, Eric; Giglia, Angelo; Mahne, Nicola; Nannarone, Stefano

    2011-01-12

    We present a technique to study depth profiles of molecular orientation in soft matter thin films with nanometer resolution. The method is based on dichroism in resonant soft X-ray reflectivity using linear s- and p-polarization. It combines the chemical sensitivity of Near-Edge X-ray Absorption Fine Structure spectroscopy to specific molecular bonds and their orientation relative to the polarization of the incident beam with the precise depth profiling capability of X-ray reflectivity. We demonstrate these capabilities on side chain liquid crystalline polymer thin films with soft X-ray reflectivity data at the carbon K edge. Optical constants of the anisotropic refractive index ellipsoid were obtained from a quantitative analysis using the Berreman formalism. For films up to 50 nm thickness we find that the degree of orientation of the long axis exhibits no depth variation and isindependent of the film thickness.

  14. Simultaneous parameter optimization of x-ray and neutron reflectivity data using genetic algorithms

    SciTech Connect

    Singh, Surendra Basu, Saibal

    2016-05-23

    X-ray and neutron reflectivity are two non destructive techniques which provide a wealth of information on thickness, structure and interracial properties in nanometer length scale. Combination of X-ray and neutron reflectivity is well suited for obtaining physical parameters of nanostructured thin films and superlattices. Neutrons provide a different contrast between the elements than X-rays and are also sensitive to the magnetization depth profile in thin films and superlattices. The real space information is extracted by fitting a model for the structure of the thin film sample in reflectometry experiments. We have applied a Genetic Algorithms technique to extract depth dependent structure and magnetic in thin film and multilayer systems by simultaneously fitting X-ray and neutron reflectivity data.

  15. Toward the development of a soft x-ray reflection imaging microscope in the Schwarzschild configuration using a soft x-ray laser at 18. 2 nm

    SciTech Connect

    Dicicco, D.; Rosser, R. ); Kim, D.; Suckewer, S. . Plasma Physics Lab.)

    1991-12-01

    We present the recent results obtained from a soft X-ray reflection imaging microscope in the Schwarzschild configuration. The microscope demonstrated a spatial resolution of 0.7 {mu}m with a magnification of 16 at 18.2 nm. The soft X-ray laser at 18.2 nm was used as an X-ray source. Mo/Si multilayers were coated on the Schwarzschild optics and the normal incidence reflectivity at 18.2 nm per surface was measured to be {approximately} 20 %. 18 refs., 6 figs.

  16. Waiting in the Wings: Reflected X-ray Emission from the Homunculus Nebula

    NASA Technical Reports Server (NTRS)

    Corcoran, M. F.; Hamaguchi, K.; Gull, T.; Davidson, K.; Petre, R.; Hillier, D. J.; Smith, N.; Damineli, A.; Morse, J. A.; Walborn, N. R.

    2004-01-01

    We report the first detection of X-ray emission associated with the Homunculus Nebula which surrounds the supermassive star eta Carinae. The emission is characterized by a temperature in excess of 100 MK, and is consistent with scattering of the time-delayed X-ray flux associated with the star. The nebular emission is bright in the northwestern lobe and near the central regions of the Homunculus, and fainter in the southeastern lobe. We also report the detection of an unusually broad Fe K fluorescent line, which may indicate fluorescent scattering off the wind of a companion star or some other high velocity outflow. The X-ray Homunculus is the nearest member of the small class of Galactic X-ray reflection nebulae, and the only one in which both the emitting and reflecting sources are distinguishable.

  17. Investigating the reflection contribution to the X-ray emission of Ton S180

    NASA Astrophysics Data System (ADS)

    Nardini, E.; Fabian, A. C.; Walton, D. J.

    2012-07-01

    There is now growing evidence that the soft X-ray excess is almost ubiquitous among unobscured active galaxies. In spite of the various interpretations that have been considered in the past few years, the nature of this foremost spectral feature is not firmly established yet. In this context, we review from a reflection perspective the three highest quality X-ray observations of the narrow-line type 1 Seyfert galaxy Tonantzintla (Ton) S180, obtained by XMM-Newton and Suzaku. The X-ray spectrum of Ton S180 shows only moderate variations over a time span of several years, suggesting that the same physical process accounts for the bulk of the broad-band X-ray emission at the different epochs, and that the properties of the X-ray source are fairly stable. We have successfully applied in our spectral analysis a dual-reflector model, consisting of two separate components: one arises from the surface of the accretion disc, is highly ionized and blurred by relativistic effects; the other is cold, quite faint and can be associated with a distant reprocessor. Due to the strength and the nearly power-law shape of its soft excess emission, Ton S180 is one of the most challenging sources to test the X-ray reflection scenario. In this work we provide a clear illustration of the great potential and spectral flexibility of blurred reflection models, while discussing some of their current limitations and possible shortcomings.

  18. Micro-imaging of buried layers and interfaces in ultrathin films by X-ray reflectivity

    NASA Astrophysics Data System (ADS)

    Jiang, Jinxing; Hirano, Keiichi; Sakurai, Kenji

    2016-09-01

    X-ray reflectivity is a promising technique for characterizing buried layers and interfaces in ultrathin films because of its ability to probe the electron density profile along the depth in a non-destructive manner. While routine X-ray reflectivity assumes the in-plane uniformity of the sample to be measured, it is also quite important to see buried inhomogeneous/patterned layers and interfaces. The present paper describes the addition of spatial resolution and imaging capability to an X-ray reflectivity technique to visualize surfaces and buried interfaces. To visualize quite wide viewing area size quickly, the image reconstruction scheme has been employed instead of the scanning of microbeam. Though the mathematics is quite close to X-ray computer tomography, the technique gives the image contrast caused by the difference in reflectivity at each in-plane point in the thin film sample. By choosing a grazing angle, the image gives inhomogeneity of X-ray reflectivity at the specific wavevector transfer. With a collimated monochromatic synchrotron X-ray beam of 0.05 mm (H) × 8 mm (V), the intensity profiles of X-ray reflection projections have been taken at many different in-plane rotation angles, from 0° to 180°. We have succeeded in visualizing buried layers and interfaces of the 8 mm dia area with the spatial resolution of better than 20 μm. Because of the brilliance of synchrotron radiation, the typical measuring time is shorter than 1 min. Three analytical cases have been discussed: (i) imaging of a buried layer and an interface covered by a protection layer, (ii) distinguishing different local parts of different thicknesses in an ultrathin film, and (iii) selective imaging of a specific metal in the thin film form.

  19. X-ray Reflected Spectra from Accretion Disk Models. II. Diagnostic Tools for X-ray Observations

    NASA Astrophysics Data System (ADS)

    García, J.; Kallman, T. R.; Mushotzky, R. F.

    2011-04-01

    We present a comprehensive study of the emission spectra from accreting sources. We use our new reflection code to compute the reflected spectra from an accretion disk illuminated by X-rays. This set of models covers different values of ionization parameter, solar iron abundance, and photon index for the illuminating spectrum. These models also include the most complete and recent atomic data for the inner shell of the iron and oxygen isonuclear sequences. We concentrate our analysis on the 2-10 keV energy region and in particular on the iron K-shell emission lines. We show the dependency of the equivalent width (EW) of the Fe Kα on the ionization parameter. The maximum value of the EW is ~800 eV for models with log ξ ~ 1.5 and decreases monotonically as ξ increases. For lower values of ξ, the Fe Kα EW decreases to a minimum near log ξ ~ 0.8. We produce simulated CCD observations based on our reflection models. For low-ionized, reflection-dominated cases, the 2-10 keV energy region shows a very broad, curving continuum that cannot be represented by a simple power law. We show that in addition to the Fe K-shell emission, there are other prominent features such as the Si and S Lα lines, a blend of Ar VIII-XI lines, and the Ca X Kα line. In some cases, the S XV blends with the He-like Si radiative recombination continua producing a broad feature that cannot be reproduced by a simple Gaussian profile. This could be used as a signature of reflection.

  20. X-Ray Reflected Spectra from Accretion Disk Models. II. Diagnostic Tools for X-Ray Observations

    NASA Technical Reports Server (NTRS)

    Garcia, J.; Kallman, T. R.; Mushotzky, R. F.

    2011-01-01

    We present a comprehensive study of the emission spectra from accreting sources. We use our new reflection code to compute the reflected spectra from an accretion disk illuminated by X-rays. This set of models covers different values of ionization parameter, solar iron abundance and photon index for the illuminating spectrum. These models also include the most complete and recent atomic data for the inner-shell of the iron and oxygen isonuclear sequences. We concentrate our analysis to the 2 - 10 keV energy region, and in particular to the iron K-shell emission lines. We show the dependency of the equivalent width (EW) of the Fe Ka with the ionization parameter. The maximum value of the EW is approx. 800 eV for models with log Epsilon approx. 1.5, and decreases monotonically as Epsilon increases. For lower values of Epsilon the Fe K(alpha) EW decreases to a minimum near log Epsilon approx. 0.8. We produce simulated CCD observations based on our reflection models. For low ionized, reflection dominated cases, the 2 -10 keV energy region shows a very broad, curving continuum that cannot be represented by a simple power-law. We show that in addition to the Fe K-shell emission, there are other prominent features such as the Si and S L(alpha) lines, a blend of Ar VIII-XI lines, and the Ca x K(alpha) line. In some cases the S xv blends with the He-like Si RRC producing a broad feature that cannot be reproduced by a simple Gaussian profile. This could be used as a signature of reflection.

  1. X-RAY REFLECTED SPECTRA FROM ACCRETION DISK MODELS. II. DIAGNOSTIC TOOLS FOR X-RAY OBSERVATIONS

    SciTech Connect

    GarcIa, J.; Kallman, T. R.; Mushotzky, R. F. E-mail: timothy.r.kallman@nasa.gov

    2011-04-20

    We present a comprehensive study of the emission spectra from accreting sources. We use our new reflection code to compute the reflected spectra from an accretion disk illuminated by X-rays. This set of models covers different values of ionization parameter, solar iron abundance, and photon index for the illuminating spectrum. These models also include the most complete and recent atomic data for the inner shell of the iron and oxygen isonuclear sequences. We concentrate our analysis on the 2-10 keV energy region and in particular on the iron K-shell emission lines. We show the dependency of the equivalent width (EW) of the Fe K{alpha} on the ionization parameter. The maximum value of the EW is {approx}800 eV for models with log {xi} {approx} 1.5 and decreases monotonically as {xi} increases. For lower values of {xi}, the Fe K{alpha} EW decreases to a minimum near log {xi} {approx} 0.8. We produce simulated CCD observations based on our reflection models. For low-ionized, reflection-dominated cases, the 2-10 keV energy region shows a very broad, curving continuum that cannot be represented by a simple power law. We show that in addition to the Fe K-shell emission, there are other prominent features such as the Si and S L{alpha} lines, a blend of Ar VIII-XI lines, and the Ca X K{alpha} line. In some cases, the S XV blends with the He-like Si radiative recombination continua producing a broad feature that cannot be reproduced by a simple Gaussian profile. This could be used as a signature of reflection.

  2. Seeing to the Event Horizon: Probing Accretion Physics with X-ray Reflection

    NASA Astrophysics Data System (ADS)

    Wilkins, Dan

    2015-09-01

    Accretion onto supermassive black holes in active galactic nuclei is known to power some of the most luminous objects we see in the Universe, which through their vast energy outputs must have played an important role in shaping the large scale structure of the Universe we see today. Much remains unknown, however, about the fine details of this process; exactly how energy is liberated from accretion flows onto black holes, how the 'corona' that produces the intense X-ray continuum is formed and what governs this process over time. I will outline how the detection of X-rays reflected from the discs of accreting material around black holes by the present generation of large X-ray observatories, shifted in energy and blurred by relativistic effects in the strong gravitational field close to the black hole, has enabled measurements of the inner regions of the accretion flow in unprecedented detail. In particular, exploiting the shift in energy of atomic emission lines by relativistic effects as a function of location on the disc has enabled the measurement of the illumination pattern of the accretion flow by the X-ray continuum from which the geometry of the emitting region can be inferred and how the detection of time lags between the primary and reflected X-rays owing to the additional path the reflected rays must travel between the corona and the disc places further constraints on the nature of the emitting corona. These techniques allow the evolution of the corona that accompanies transitions from high to low X-ray flux to be studied, giving clues to the physical process that forms and powers the intense X-ray source and uncovering evidence for the potential launching of jets. I will discuss the great steps forward in understanding accretion physics that can be made with the Athena X-ray observatory, combining detailed analysis of observations with predictions and models from general relativistic ray tracing simulations. In particular, I will discuss how high

  3. Two-stage reflective optical system for achromatic 10 nm x-ray focusing

    NASA Astrophysics Data System (ADS)

    Motoyama, Hiroto; Mimura, Hidekazu

    2015-12-01

    Recently, coherent x-ray sources have promoted developments of optical systems for focusing, imaging, and interferometers. In this paper, we propose a two-stage focusing optical system with the goal of achromatically focusing pulses from an x-ray free-electron laser (XFEL), with a focal width of 10 nm. In this optical system, the x-ray beam is expanded by a grazing-incidence aspheric mirror, and it is focused by a mirror that is shaped as a solid of revolution. We describe the design procedure and discuss the theoretical focusing performance. In theory, soft-XFEL lights can be focused to a 10 nm area without chromatic aberration and with high reflectivity; this creates an unprecedented power density of 1020 W cm-2 in the soft-x-ray range.

  4. A theoretical analysis of reflection of X-rays from water at energies relevant for diagnostics

    SciTech Connect

    Arsenovic, Dusan; Davidovic, Dragomir M.; Vukanic, Jovan

    2003-01-24

    The reflection of X-rays from a semi-infinite water target, for energies used in X-ray diagnostics, is treated by the analog Monte Carlo simulation. In the developed procedure it was possible to calculate separately contributions of photons scattered, before reflection, fixed number of times with target electrons. It turned out that multiple collision type of reflection dominates at all energies investigated, whenever the absorption is small. The same process was also treated analytically as the classical albedo problem for isotropic scattering without energy loss. Very good agreement of results of the two approaches is obtained.

  5. Doppler-shifted reflections of X rays in beamfoil spectroscopy

    NASA Technical Reports Server (NTRS)

    Bernstein, E. M.; Mcintyre, L. C., Jr.

    1976-01-01

    Carbon foils were positioned at roughly 10 deg to the conventional perpendicular position so that the spectrometer would view the beam on emergence from the foil, with no radiation shielded by a bowed or wrinkled foil or by the foil holder. Extraneous peaks due to reflected radiation were detected in the spectrum obtained with the tilted foil. A large satellite appears longward of the spectral line and is attributed to Doppler-shifted radiation reflected from the foil surface. Special tests arranged to validate the origin of the satellites are described. The relative intensity of the reflected radiation compared with the direct radiation observed is at variance with the relative intensities reported for longer wavelengths. The reasons for this, possible effects of spectrometer geometry, and applications in the investigation or generation of polarization remain to be investigated

  6. Characterization of atmospheric aerosols using Synchroton radiation total reflection X-ray fluorescence and Fe K-edge total reflection X-ray fluorescence-X-ray absorption near-edge structure

    NASA Astrophysics Data System (ADS)

    Fittschen, U. E. A.; Meirer, F.; Streli, C.; Wobrauschek, P.; Thiele, J.; Falkenberg, G.; Pepponi, G.

    2008-12-01

    In this study a new procedure using Synchrotron total reflection X-ray fluorescence (SR-TXRF) to characterize elemental amounts in atmospheric aerosols down to particle sizes of 0.015 um is presented. The procedure was thoroughly evaluated regarding bounce off effects and blank values. Additionally the potential of total reflection X-ray fluorescence-X-ray absorption near edge structure (SR-TXRF-XANES) for speciation of FeII/III down to amounts of 34 pg in aerosols which were collected for 1 h is shown. The aerosols were collected in the city of Hamburg with a low pressure Berner impactor on Si carriers covered with silicone over time periods of 60 and 20 min each. The particles were collected in four and ten size fractions of 10.0-8.0 μm, 8.0-2.0 μm, 2.0-0.13 μm 0.13-0.015 μm (aerodynamic particle size) and 15-30 nm, 30-60 nm, 60-130 nm, 130-250 nm, 250-500 nm, 0.5-1 μm, 1-2 μm, 2-4 μm, 4-8 μm, 8-16 μm. Prior to the sampling "bounce off" effects on Silicone and Vaseline coated Si carriers were studied with total reflection X-ray fluorescence. According to the results silicone coated carriers were chosen for the analysis. Additionally, blank levels originating from the sampling device and the calibration procedure were studied. Blank levels of Fe corresponded to 1-10% of Fe in the aerosol samples. Blank levels stemming from the internal standard were found to be negligible. The results from the Synchroton radiation total reflection X-ray fluorescence analysis of the aerosols showed that 20 min of sampling time gave still enough sample material for elemental determination of most elements. For the determination of the oxidation state of Fe in the aerosols different Fe salts were prepared as a reference from suspensions in isopropanol. The results from the Fe K-edge Synchroton radiation total reflection X-ray fluorescence-X-ray absorption near-edge structure analysis of the aerosol samples showed that mainly Fe(III) was present in all particle size fractions.

  7. High-resolution residual layer thickness metrology using x-ray reflectivity

    NASA Astrophysics Data System (ADS)

    Lee, Hae-Jeong; Soles, Christopher L.; Ro, Hyun W.; Hines, Daniel R.; Jones, Ronald L.; Lin, Eric K.; Wu, Wen-li

    2005-05-01

    Controlling the thickness and uniformity of the unpatterned, residual layer is a critical challenge to sub-50 nm patterning with nanoimprint lithography (NIL). While nanometer level uniformity is essential, there is currently a lack of metrological capability for residual layer characterization. Specular X-ray reflectivity (SXR) is a versatile and widely used metrology to quantify the thickness, density, and roughness of thin smooth films. Here we extend specular X-ray reflectivity (SXR) to measure the thickness of the residual layer with sub-nm resolution. In addition to the residual layer thickness, X-ray reflectivity also reveals detailed information about the pattern height, the line to space ratio, and the relative line width variations of the pattern as a function of the pattern height.

  8. Melting of 1-Alcohol Mololayers at the Air-Water Interface. I. X-Ray Reflectivity Investigations

    NASA Astrophysics Data System (ADS)

    Rieu, J. P.; Legrand, J. F.; Renault, A.; Berge, B.; Ocko, B. M.; Wu, X. Z.; Deutsch, M.

    1995-04-01

    The melting of 1-alcohol monolayers adsorbed at the air-water interface has been studied using X-ray reflectivity. This technique allows for an accurate determination of the thickness and the density of the monolayer. The reflectivity, both in specular and non-specular directions, over a large temperature range of different chain lengths (from C{10} to C{16}) have been interpreted using a model taking into account the scattering from thermally induced capillary-wave fluctuations and the instrumental resolution. The density and the thickness of the aliphatic layer exhibit a clear discontinuity at the solid-liquid transition. Large changes with temperature in the packing of the monolayer are observed in both the solid and the liquid phase. In the crystal phase, the fitted thicknesses are lower than all-trans molecular chain lengths. In the liquid phase, the density remains 10% larger than in bulk liquid phases. La fusion de monocouches de 1-alcool adsorbées à l'interface air-eau est étudiée par réflectivité des rayons X. Cette technique permet une détermination précise de l'épaisseur et de la densité de la monocouche. Les mesures de réflectivité effectuées dans chacune des directions spéculaire et non spéculaire, ont été interprétées à l'aide d'un modèle tenant compte de la résolution expérimentale et de la diffusion par les fluctuations capillaires thermiques. La densité et l'épaisseur de la couche aliphatique présentent une claire discontinuité à la transition solide-liquide. D'importants changements de la compacité de la monocouche sont observés dans chacune des phases solide et liquide sous l'effet de la température. Dans la phase cristalline, les épaisseurs de la monocouche obtenues sont plus petites que celles de molécules dans une conformation “trans-trans”. Dans la phase liquide, la valeur de la densité reste 10% plus élevée que celle de la phase liquide volumique 3D.

  9. NASA's Chandra Finds That Saturn Reflects X-rays From Sun

    NASA Astrophysics Data System (ADS)

    2005-05-01

    When it comes to mysterious X-rays from Saturn, the ringed planet may act as a mirror, reflecting explosive activity from the sun, according to scientists using NASA's Chandra X-ray Observatory. The findings stem from the first observation of an X-ray flare reflected from Saturn's low-latitudes - the region that correlates to Earth's equator and tropics. Led by Dr. Anil Bhardwaj, a planetary scientist at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Ala., the study revealed that Saturn acts as a diffuse mirror for solar X-rays. Counting photons - particles that carry electromagnetic energy including X-rays - was critical to this discovery. For every few thousand X-ray photons Saturn receives from the sun, it reflects a single X-ray photon back. Previous studies revealed that Jupiter, with a diameter 11 times that of Earth, behaves in a similar fashion. Saturn is about 9.5 times as big as Earth, but is twice as far from Earth as Jupiter. "The bigger the planet and nearer to the Sun, the more solar photons it will intercept - resulting in more reflected X-rays," said Bhardwaj. "These results imply we could use giant planets like Jupiter and Saturn as remote-sensing tools. By reflecting solar activity back to us, they could help us monitor X-ray flaring on portions of the sun facing away from Earth's space satellites." Massive solar explosions called flares often accompany coronal mass ejections, which emit solar material and magnetic field. When directed toward the Earth, these ejections can wreak havoc on communication systems from cell phones to satellites. Even as the research appears to have solved one mystery - the source of Saturn's X-rays, it fueled longstanding questions about magnetic fields. Earth's magnetic field is the reason compasses work, since the field acts like a huge bar magnet, causing the magnetic north pole of a compass to point to the magnetic south pole of the Earth. In addition, migratory birds seem to sense the magnetic field

  10. X-ray microscopy using reflection targets based on SEM with tungsten filament

    NASA Astrophysics Data System (ADS)

    Liu, Junbiao; Ma, Yutian; Zhao, Weixia; Niu, Geng; Chu, Mingzhang; Yin, Bohua; Han, Li; Liu, Baodong

    2016-10-01

    X-ray MicroandNano imaging is developed based on the conventional x-ray tomography, it can not only provide nondestructive testing with higher resolution measurement, but also be used to examine the material or the structure with low atomic number and low density. The source with micro-focal spot size is one of the key components of x-ray MicroandNano imaging. The focused electron beam from SEM bombarding the metal target can generate x-ray with ultra-small size. It is convenient to set up x-ray microscopy based on SEM for laboratory use. This paper describes a new x-ray microscopy using reflection targets based on FEI Quanta600 SEM with tungsten filament. The flat panel detector is placed outside of the vacuum chamber with 300μm thickness Be-window to isolate vacuum from the air. A stage with 3 DOFs is added to adjust the positions of the target, the SEM's sample stage is used to move sample. And the shape of target is designed as cone with 60° half cone angle to get the maximum x-ray dosage. The attenuation coefficient of Bewindow for x-ray is about 25%. Finally, the line pair card is used to evaluate the resolution and the result shows that the resolution of the system can receive less than 750nm, when the acceleration voltage is 30keV, the beam current is 160nA, the SEM working distance is 5mm and the acquisition time of the detector is 60s.

  11. Optical and x-ray alignment approaches for off-plane reflection gratings

    NASA Astrophysics Data System (ADS)

    Allured, Ryan; Donovan, Benjamin D.; DeRoo, Casey T.; Marlowe, Hannah R.; McEntaffer, Randall L.; Tutt, James H.; Cheimets, Peter N.; Hertz, Edward; Smith, Randall K.; Burwitz, Vadim; Hartner, Gisela; Menz, Benedikt

    2015-09-01

    Off-plane reflection gratings offer the potential for high-resolution, high-throughput X-ray spectroscopy on future missions. Typically, the gratings are placed in the path of a converging beam from an X-ray telescope. In the off-plane reflection grating case, these gratings must be co-aligned such that their diffracted spectra overlap at the focal plane. Misalignments degrade spectral resolution and effective area. In-situ X-ray alignment of a pair of off-plane reflection gratings in the path of a silicon pore optics module has been performed at the MPE PANTER beamline in Germany. However, in-situ X-ray alignment may not be feasible when assembling all of the gratings required for a satellite mission. In that event, optical methods must be developed to achieve spectral alignment. We have developed an alignment approach utilizing a Shack-Hartmann wavefront sensor and diffraction of an ultraviolet laser. We are fabricating the necessary hardware, and will be taking a prototype grating module to an X-ray beamline for performance testing following assembly and alignment.

  12. Testing the Pairs-Reflection Model with X-Ray Spectral Variability and X-Ray Properties of Complete Samples of Radio-Selected BL Lacertae Objects

    NASA Technical Reports Server (NTRS)

    Urry, C. Megan

    1997-01-01

    This grant was awarded to Dr. C. Megan Urry of the Space Telescope Science Institute in response to two successful ADP proposals to use archival Ginga and Rosat X-ray data for 'Testing the Pairs-Reflection model with X-Ray Spectral Variability' (in collaboration with Paola Grandi, now at the University of Rome) and 'X-Ray Properties of Complete Samples of Radio-Selected BL Lacertae Objects' (in collaboration with then-graduate student Rita Sambruna, now a post-doc at Goddard Space Flight Center). In addition, post-docs Joseph Pesce and Elena Pian, and graduate student Matthew O'Dowd, have worked on several aspects of these projects. The grant was originally awarded on 3/01/94; this report covers the full period, through May 1997. We have completed our project on the X-ray properties of radio-selected BL Lacs.

  13. Focusing hard x rays beyond the critical angle of total reflection by adiabatically focusing lenses

    DOE PAGES

    Patommel, Jens; Klare, Susanne; Hoppe, Robert; ...

    2017-03-06

    In response to the conjecture that the numerical aperture of x-ray optics is fundamentally limited by the critical angle of total reflection, the concept of adiabatically focusing refractive lenses was proposed to overcome this limit. Here, we present an experimental realization of these optics made of silicon and demonstrate that they indeed focus 20 keV x rays to a 18.4 nm focus with a numerical aperture of 1.73(9) × 10–3 that clearly exceeds the critical angle of total reflection of 1.55 mrad.

  14. Hard x-ray nanofocusing using total-reflection zone plates

    SciTech Connect

    Takano, Hidekazu Matsumura, Atsuyuki; Sakka, Kenji; Tsusaka, Yoshiyuki; Kagoshima, Yasushi; Tsuji, Takuya

    2016-01-28

    A total-reflection zone plate (TRZP), which is a reflective grating that generates a line focus of hard X-rays, was developed. Newly designed TRZPs, introducing a laminar grating concept, were fabricated with various zone parameters. The focusing performances with regard to the beam size and the diffraction efficiency were evaluated using synchrotron radiation X-rays of 10 keV energy. Although the beam sizes measured are insufficient in comparison with the ideal value, the maximum diffraction efficiency, measured at 20%, exceeds the limitations of conventional TRZPs based on a binary grating.

  15. Rapid X-ray reflectivity measurement using a new liquid interface reflectometer at SPring-8

    NASA Astrophysics Data System (ADS)

    Yano, Y. F.; Uruga, T.; Tanida, H.; Toyokawa, H.; Terada, Y.; Takagaki, M.; Yamada, H.

    2009-02-01

    X-ray reflectivity measurements of liquid surfaces were demonstrated using a recently developed liquid interface reflectometer at SPring-8. The reflectometer, equipped with a two-dimensional hybrid pixel array detector (PILATUS), achieved x-ray reflectivity towards 10-9 with an integration time at each angle of only 1 sec, offering enormous potential for rapid measurements. Time-resolved measurements at a time resolution of 1 min were performed on the adsorption process of a globular protein lysozyme on a water/air interface.

  16. X-ray reflection and scatter measurements on selected optical samples

    NASA Technical Reports Server (NTRS)

    Fields, S. A.; Reynolds, J. M.; Holland, R. L.

    1975-01-01

    The results from an experimental program to determine the reflection efficiency and scatter parameters of selected optical samples are presented. The measurements were made using 8.34A X-rays at various angles of incidence. Selected samples were contaminated after being measured and then remeasured to determine the effects of contamination. The instrumentation involved in taking the data, including the X-ray reflectometer and data processing equipment, is discussed in detail. The condition of the optical surfaces, the total reflection measurements, the scatter measurements, and the analysis are discussed.

  17. In situ anodization of aluminum surfaces studied by x-ray reflectivity and electrochemical impedance spectroscopy

    SciTech Connect

    Bertram, F. Evertsson, J.; Messing, M. E.; Mikkelsen, A.; Lundgren, E.; Zhang, F.; Pan, J.; Carlà, F.; Nilsson, J.-O.

    2014-07-21

    We present results from the anodization of an aluminum single crystal [Al(111)] and an aluminum alloy [Al 6060] studied by in situ x-ray reflectivity, in situ electrochemical impedance spectroscopy and ex situ scanning electron microscopy. For both samples, a linear increase of oxide film thickness with increasing anodization voltage was found. However, the slope is much higher in the single crystal case, and the break-up of the oxide film grown on the alloy occurs at a lower anodization potential than on the single crystal. The reasons for these observations are discussed as are the measured differences observed for x-ray reflectivity and electrochemical impedance spectroscopy.

  18. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

    DOE PAGES

    Burcklen, C.; Soufli, R.; Gullikson, E.; ...

    2016-03-24

    Here, we present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1–1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (opticalmore » constants) values for Cr.« less

  19. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

    NASA Astrophysics Data System (ADS)

    Burcklen, C.; Soufli, R.; Dennetiere, D.; Polack, F.; Capitanio, B.; Gullikson, E.; Meltchakov, E.; Thomasset, M.; Jérome, A.; de Rossi, S.; Delmotte, F.

    2016-03-01

    We present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1-1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (optical constants) values for Cr.

  20. Cr/B{sub 4}C multilayer mirrors: Study of interfaces and X-ray reflectance

    SciTech Connect

    Burcklen, C.; Meltchakov, E.; Jérome, A.; Rossi, S. de; Delmotte, F.; Soufli, R.; Dennetiere, D.; Polack, F.; Capitanio, B.; Thomasset, M.; Gullikson, E.

    2016-03-28

    We present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B{sub 4}C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B{sub 4}C-on-Cr interface, which we modeled with a 1–1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L{sub 2,3} absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (optical constants) values for Cr.

  1. Direct and quantitative comparison of pixelated density profiles to high resolution X-ray reflectivity data.

    SciTech Connect

    Fenter, Paul; Lee, S. S.; Skelton, A A; Cummings, Peter T

    2011-01-01

    A method for comparing pixelated density profiles (e.g. obtained from molecular dynamics or other computational techniques) with experimental X-ray reflectivity data both directly and quantitatively is described. The conditions under which such a comparison can be made quantitatively (e.g. with errors <1%) are determined theoretically by comparing calculated structure factors for an intrinsic continuous density profile with those obtained from density profiles that have been binned into regular spatial increments. The accuracy of the X-ray reflectivity calculations for binned density profiles is defined in terms of the inter-relationships between resolution of the X-ray reflectivity data (i.e. its range in momentum transfer), the chosen bin size and the width of the intrinsic density profile. These factors play a similar role in the application of any structure-factor calculations that involve the use of pixelated density profiles, such as those obtained from iterative phasing algorithms for inverting structures from X-ray reflectivity and coherent diffraction imaging data. Finally, it is shown how simulations of a quartz water interface can be embedded into an exact description of the bulk phases (including the substrate crystal and the fluid water, below and above the actual interface) to quantitatively reproduce the experimental reflectivity data of a solid liquid interface.

  2. X-ray reflectivity theory for determining the density profile of a liquid under nanometre confinement.

    PubMed

    Perret, Edith; Nygård, Kim; Satapathy, Dillip K; Balmer, Tobias E; Bunk, Oliver; Heuberger, Manfred; van der Veen, J Friso

    2010-07-01

    An X-ray reflectivity theory on the determination of the density profile of a molecular liquid under nanometre confinement is presented. The confinement geometry acts like an X-ray interferometer, which consists of two opposing atomically flat single-crystal mica membranes with an intervening thin liquid film of variable thickness. The X-rays reflected from the parallel crystal planes (of known structure) and the layered liquid in between them (of unknown structure) interfere with one another, making X-ray reflectivity highly sensitive to the liquid's density profile along the confinement direction. An expression for the reflected intensity as a function of momentum transfer is given. The total structure factor intensity for the liquid-filled confinement device is derived as a sum of contributions from the inner and outer crystal terminations. The method presented readily distinguishes the confined liquid from the liquid adsorbed on the outer mica surfaces. It is illustrated for the molecular liquid tetrakis(trimethyl)siloxysilane, confined by two mica surfaces at a distance of 8.6 nm.

  3. X-ray reflectivity theory for determining the density profile of a liquid under nanometre confinement

    PubMed Central

    Perret, Edith; Nygård, Kim; Satapathy, Dillip K.; Balmer, Tobias E.; Bunk, Oliver; Heuberger, Manfred; van der Veen, J. Friso

    2010-01-01

    An X-ray reflectivity theory on the determination of the density profile of a molecular liquid under nanometre confinement is presented. The confinement geometry acts like an X-ray interferometer, which consists of two opposing atomically flat single-crystal mica membranes with an intervening thin liquid film of variable thickness. The X-rays reflected from the parallel crystal planes (of known structure) and the layered liquid in between them (of unknown structure) interfere with one another, making X-ray reflectivity highly sensitive to the liquid’s density profile along the confinement direction. An expression for the reflected intensity as a function of momentum transfer is given. The total structure factor intensity for the liquid-filled confinement device is derived as a sum of contributions from the inner and outer crystal terminations. The method presented readily distinguishes the confined liquid from the liquid adsorbed on the outer mica surfaces. It is illustrated for the molecular liquid tetrakis(trimethyl)siloxysilane, confined by two mica surfaces at a distance of 8.6 nm. PMID:20567078

  4. Total reflection X-ray photoelectron spectroscopy as a semiconductor lubricant elemental analysis method

    NASA Astrophysics Data System (ADS)

    Alshehabi, Abbas; Sasaki, Nobuharu; Kawai, Jun

    2015-12-01

    Photoelectron spectra from a typical hard disk storage media device (HDD) were measured at total reflection and non-total reflection at unburnished, acetone-cleaned, and argon-sputtered conditions. F, O, N, and C usually making the upper layer of a typical hard disk medium were detected. Enhancement of the photoelectron emission of the fluorocarbon lubricant was observed at total reflection. Pt and Co were only found by non-total X-ray photoelectron spectroscopy (XPS) because they are constituents of a deeper region than the top and interface regions. Argon-sputtered, ultrasonic acetone-cleaned, and unburnished top layers were compared at total and non-total reflection conditions. Total reflection X-ray photoelectron spectroscopy (TRXPS) is demonstrated to be a powerful tool for storage media lubrication layer chemical state analysis, reliable for industrial quality control application , and reproducible.

  5. X-ray Reflectivity Measurements of Nanoscale Structures: Limits of the Effective Medium Approximation

    SciTech Connect

    Lee, Hae-Jeong; Soles, Christopher L.; Kang, Shuhui; Wook Ro, Hyun; Lin, Eric K.; Wu, Wen-li

    2007-09-26

    Specular X-ray reflectivity (SXR) can be used, in the limit of the effective medium approximation (EMA), as a high-resolution shape metrology for periodic patterns on a smooth substrate. The EMA means that the density of the solid patterns and the spaces separating the periodic patterns are averaged together. In this limit the density profile as a function of pattern height obtained by SXR can be used to extract quantitative pattern profile information. Here we explore the limitations of SXR as a pattern shape metrology by studying a series of linear grating structures with periodicities ranging from 300 nm to 16 {mu}m and determining at which length scales the EMA breaks down. We also study the angular dependence of the grating orientation with respect to the incident X-ray beam. The gratings systematically are rotated through a series of azimuthal angles with the incident X-ray beams ranging from 0 deg. to 90 deg. . The applicability of the EMA is related to the coherence length of the X-ray source. When the coherence length of beam is larger than the physical dimension of grating periodicities, EMA can be applied for characterizing nanostructures. For our slit-collimated X-ray source, the coherence length in the direction parallel to the long axis of the slit is on the order of 900 nm while the coherence length along the main axis of the beam appears to be in the range of (22 to 26) {mu}m.

  6. Critical Reexamination of Resonant Soft X-Ray Bragg Forbidden Reflections in Magnetite

    SciTech Connect

    Wilkins, S.B.; Di Matteo, S.; Beale, T.A.W.; Joly, Y.; Mazzoli, C.; Hatton, P.D.; Bencok, P.; Yakhou, F.; Brabers, V.A.M.

    2009-05-01

    Magnetite, Fe{sub 3}O{sub 4}, displays a highly complex low-temperature crystal structure that may be charge and orbitally ordered. Many of the recent experimental claims of such ordering rely on resonant soft x-ray diffraction at the oxygen K and iron L edges. We have reexamined this system and undertaken soft x-ray diffraction experiments on a high-quality single crystal. Contrary to previous claims in the literature, we show that the intensity observed at the Bragg forbidden (001/2){sub c} reflection can be explained purely in terms of the low-temperature structural displacements around the resonant atoms. This does not necessarily mean that magnetite is not charge or orbitally ordered but rather that the present sensitivity of resonant soft x-ray experiments does not allow conclusive demonstration of such ordering.

  7. Characterization of ion beam sputtered deposited W/Si multilayers by grazing incidence x-ray diffraction and x-ray reflectivity technique

    SciTech Connect

    Dhawan, Rajnish Rai, Sanjay

    2016-05-23

    W/Si multilayers four samples have been deposited on silicon substrate using ion beam sputtering system. Thickness of tungsten (W) varies from around 10 Å to 40 Å while the silicon (Si) thickness remains constant at around 30 Å in multilayers [W-Si]{sub x4}. The samples have been characterized by grazing incidence X-ray diffraction (GIXRD) and X-ray reflectivity technique (XRR). GIXRD study shows the crystalline behaviour of W/Si multilayer by varying W thickness and it is found that above 20 Å the W film transform from amorphous to crystalline phase and X-ray reflectivity data shows that the roughnesses of W increases on increasing the W thicknesses in W/Si multilayers.

  8. Making use of x-ray optical effects in photoelectron-, Auger electron-, and x-ray emission spectroscopies: Total reflection, standing-wave excitation, and resonant effects

    SciTech Connect

    Yang, S.-H.; Gray, A. X.; Kaiser, A. M.; Mun, B. S.; Sell, B. C.; Kortright, J. B.; Fadley, C. S.

    2013-02-21

    We present a general theoretical methodology and related open-access computer program for carrying out the calculation of photoelectron, Auger electron, and x-ray emission intensities in the presence of several x-ray optical effects, including total reflection at grazing incidence, excitation with standing-waves produced by reflection from synthetic multilayers and at core-level resonance conditions, and the use of variable polarization to produce magnetic circular dichroism. Calculations illustrating all of these effects are presented, including in some cases comparisons to experimental results. Sample types include both semi-infinite flat surfaces and arbitrary multilayer configurations, with interdiffusion/roughness at their interfaces. These x-ray optical effects can significantly alter observed photoelectron, Auger, and x-ray intensities, and in fact lead to several generally useful techniques for enhancing surface and buried-layer sensitivity, including layer-resolved densities of states and depth profiles of element-specific magnetization. The computer program used in this study should thus be useful for a broad range of studies in which x-ray optical effects are involved or are to be exploited in next-generation surface and interface studies of nanoscale systems.

  9. Total reflection X-ray fluorescence and grazing incidence X-ray spectrometry — Tools for micro- and surface analysis. A review

    NASA Astrophysics Data System (ADS)

    von Bohlen, Alex

    2009-09-01

    A review of Total Reflection X-ray Spectrometry and related methods covering literature of four decades is presented. History, theory, instrumentation, sample preparation, and applications are summarized and some examples are given. New developments and trends are discussed with respect to emerging nano-technologies in all fields of sciences.

  10. [Technology Development for X-Ray Reflection for the Constellation-X Reflection Grating Spectrometer (RGS)

    NASA Technical Reports Server (NTRS)

    Schattenburg, Mark L.

    2003-01-01

    This Grant covers MIT support for the technology development of x-ray reflection gratings for the Constellation-X Reflection Grating Spectrometer (RGS). Since the start of the Grant MIT has extended its previously-developed patterning and super-smooth, blazed grating fabrication technology to ten-times smaller grating periods and ten-times larger blaze angles to demonstrate feasibility and performance in the off-plane grating geometry. In the past year we successfully developed several nanoimprint grating replication methods that achieved very high fidelity replication of master silicon gratings. Grating geometry on the nano and macro scales were faithfully replicated, demonstrating the viability of the process for manufacturing the thousands of gratings required for the RGS. We also successfully developed an improved metrology truss for holding test grating substrates during metrology. The flatness goal of grating substrates is under 500 nm. In the past, grating holders would cause non-repeatable distortion of >> 500 nm to the substrates due to friction and gravity sag. The new holder has a repeatability of under 50 nm which is adequate for the proposed RGS grating substrates.

  11. Structural studies of mixed lipid bilayers on solid substrates using x-ray reflectivity

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Mukhopadhyay, Mrinmay; Ma, Yicong; Sinha, Sunil; Jiang, Zhang; Decaro, Curt; Berry, Justin; Lurio, Laurence; Brozell, Adrian; Parikh, Atul

    2009-03-01

    The lipid bilayers of natural membranes generally exist in a fluid state which occurs above the gel to liquid crystalline phase transition temperature. Knowledge of the structure of such bilayers is important for understanding fundamental biological processes mediated by or occurring within membranes. We have performed systematic measurements on bilayers of 1,2-Dipalmitoyl-sn-Glycero-3-Phosphoethanolamine (DPPE) and its mixture with 1,2-Dioleoyl-sn-Glycero-3-Phosphocholine (DOPC) and cholesterol (CH) on silicon substrates with x-ray reflectivity both below and above their phase transition temperatures. Structural variations as a function of temperature are demonstrated by fitting the reflectivity data with both a model dependent and a model independent routine. Studies of Au nanoparticle labeled DOPC and DOPC + DPPE + CH mixture are also performed and the location of Au nanoparticles in these bilayers is established by analyzing the x-ray reflectivity data.

  12. X-ray reflection from a water surface investigated by a new liquid interface reflectometer at SPring-8

    NASA Astrophysics Data System (ADS)

    Yano, Yohko F.; Uruga, Tomoya; Tanida, Hajime; Toyokawa, Hidenori; Terada, Yasuko; Takagaki, Masashi

    2007-10-01

    X-ray reflection measurement of a water surface was demonstrated using recently developed liquid interface reflectometer at SPring-8. The reflectometer equipped with two-dimensional hybrid pixel array detector, PILATUS, achieved x-ray reflectivity towards 10-9 with the integration time at each angle of only 1 sec, having enormous potential for quick measurements.

  13. The x ray reflectivity of the AXAF VETA-I optics

    NASA Technical Reports Server (NTRS)

    Kellogg, Edwin M.; Chartas, G.; Graessle, D.; Hughes, John P.; Vanspeybroeck, Leon; Zhao, Ping; Weisskopf, M. C.; Elsner, R. F.; Odell, S. L.

    1992-01-01

    The x-ray reflectivity of the VETA-I optic, the outermost shell of the AXAF x-ray telescope, with a bare Zerodur surface, is measured and compared with theoretical predictions. Measurements made at energies of 0.28, 0.9, 1.5, 2.1, and 2.3 keV are compared with predictions based on ray trace calculations. The data were obtained at the x-ray calibrations facility at Marshall Space Flight Center with an electron impact x-ray source located 528 m from the grazing incidence mirror. The source used photoelectric absorption filters to eliminate bremsstrahlung continuum. The mirror has a diameter of 1.2 m and a focal length of 10 m. The incident and reflected x-ray flux are detected using two proportional counters, one located in the incident beam of x-rays at the entrance aperture of the VETA-I, and the other in the focal plane behind an aperture of variable size. Results on the variation of the reflectivity with energy as well as the absolute value of the reflectivity are presented. We also present a synchrotron reflectivity measurement with high energy resolution over the range 0.26 to 1.8 keV on a flat Zerodur sample, done at NSLS. We present evidence for contamination of the flat by a thin layer of carbon on the surface, and the possibility of alteration of the surface composition of the VETA-I mirror perhaps by the polishing technique. The overall agreement between the measured and calculated effective area of VETA-I is between 2.6 percent and 10 percent, depending on which model for the surface composition is adopted. Measurements at individual energies deviate from the best-fitting calculation to 0.3 to 0.8 percent, averaging 0.6 percent at energies below the high energy cutoff of the mirror reflectivity, and are as high as 20.7 percent at the cutoff. We also discuss the approach to the final preflight calibration of the full AXAF flight mirror.

  14. Observation of total external reflection of x rays from a liquid-solid interface

    NASA Astrophysics Data System (ADS)

    Touryanski, A. G.; Pirshin, I. V.

    2007-07-01

    A new experimental scheme for the measurement of the x-ray reflectivity R from a liquid-solid interface in the range of angles of total external reflection is proposed. An x-ray beam is transmitted through a plane channel filled with a liquid under investigation. The channel is formed by two optically polished plates, one of which being the substrate under study. To eliminate the edge effects caused by surface tension, polymer films with a lyophilic coating are used as windows of the channel. For wate-silicon and glycerol-silicon interfaces, the angular dependences of R and the parameters of the interfaces are measured with the scheme developed using the CuK α (8.05 keV) and CuK β (8.91 keV) lines.

  15. Application of the Total Reflection X-ray Fluorescence technique to trace elements determination in tobacco

    NASA Astrophysics Data System (ADS)

    Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

    2008-12-01

    Many studies have identified an important number of toxic elements along with organic carcinogen molecules and radioactive isotopes in tobacco. In this work we have analyzed by Total Reflection X-Ray Fluorescence 9 brands of cigarettes being manufactured and distributed in the Mexican market. Two National Institute of Standards and Technology standards and a blank were equally treated at the same time. Results show the presence of some toxic elements such as Pb and Ni. These results are compared with available data for some foreign brands, while their implications for health are discussed. It can be confirmed that the Total Reflection X-Ray Fluorescence method provides precise (reproducible) and accuracy (trueness) data for 15 elements concentration in tobacco samples.

  16. Protein Folding at the Air-Water Interface Studied with X-Ray Reflectivity

    NASA Astrophysics Data System (ADS)

    Gidalevitz, David; Huang, Zhengqing; Rice, Stuart A.

    1999-03-01

    We report the results of x-ray reflectivity measurements of thin films formed by different water-soluble proteins at the air-aqueous solution interface. It is demonstrated that glucose oxidase, alcohol dehydrogenase, and urease molecules denaturate at the air-aqueous solution interface to form 8- to 14- angstrom -thick peptide sheets. X-ray reflectivity data indicate that the spreading of a lipid monolayer at the aqueous solution surface before protein injection does not prevent proteins from unfolding. On the other hand, crosslinking of proteins results in intact enzyme layers at the subphase surface. A model that involves interaction of glucose oxidase molecules with a phospholipid monolayer is proposed. In this model, an observed decrease of the lipid electron density in the protein presence is explained in terms of "holes" in the monolayer film caused by protein molecule adsorption.

  17. Determination of trace elements in macrozoobenthos samples by total reflection X-ray fluorescence analysis

    NASA Astrophysics Data System (ADS)

    Miesbauer, Hermann; Köck, Günter; Füreder, Leo

    2001-11-01

    The paper describes the analysis of a set of metals in macrozoobenthos samples from a river in Western Austria by using total reflection X-ray fluorescence analysis (TXRF). Metal concentrations in aquatic insect larvae from an industrially contaminated site are significantly higher than in larvae from a reference site. Furthermore, species-specific differences in metal accumulation were found. TXRF allows multi-element analysis of very low metal concentrations in very small sample masses (e.g. single aquatic insect larvae with a dry weight of only a few milligrams). Due to its multi-element capability and high sensitivity total reflection X-ray fluorescence analysis is a valuable tool for biomonitoring studies of metal contamination in aquatic ecosystems.

  18. Airborne Particulate Matter (PM) filter analysis and modeling by Total reflection X-Ray Fluorescence (TXRF) and X-Ray Standing Wave (XSW)

    PubMed Central

    Borgese, L.; Salmistraro, M.; Gianoncelli, A; Zacco, A.; Lucchini, R.; Zimmerman, N.; Pisani, L.; Siviero, G.; Depero, L. E.; Bontempi, E.

    2011-01-01

    This work is presented as an improvement of a recently introduced method for airborne particulate matter (PM) filter analysis [1]. X-ray Standing Wave (XSW) and Total reflection X-Ray Fluorescence (TXRF) were performed with a new dedicated laboratory instrumentation. The main advantage of performing both XSW and TXRF, is the possibility to distinguish the nature of the sample: if it is a small droplet dry residue, a thin film like or a bulk sample; and to select the angle of total reflection to make TXRF measurements. Finally, the possibility to switch the X-ray source allows to measure with more accuracy lighter and heavier elements (with a a change in X-ray anode, for example from Mo to Cu). The aim of the present study is to lay the theoretical foundation of the new proposed method for airborne PM filters quantitative analysis improving the accuracy and efficiency of quantification by means of an external standard. The theoretical model presented and discussed demonstrated that airborne PM filters can be considered as thin layers. A set of reference samples is prepared in laboratory and used to obtain a calibration curve. Our results demonstrate that the proposed method for quantitative analysis of air PM filters is affordable and reliable without the necessity to digest filters to obtain quantitative chemical analysis, and that the use of XRW improve the accuracy of TXRF analysis. PMID:22284465

  19. X-ray specular reflectivity study of a critical binary fluid mixture.

    PubMed

    Marschand, L W; Brown, M; Lurio, L B; Law, B M; Uran, S; Kuzmenko, I; Gog, T

    2005-07-01

    We have used direct inversion of x-ray reflectivity data to extract the liquid-vapor interface composition profile and the related critical scaling function of a binary mixture of dodecane and tetrabromoethane. The mixture was in the one-phase region above its critical point. The results indicate the formation of a monolayer of the lower surface tension component followed by an abrupt change to a mixed composition which gradually relaxes to the bulk composition deep within the fluid.

  20. Illumination of Cation Sorption Mechanisms on Muscovite Using X-ray Reflectivity

    NASA Astrophysics Data System (ADS)

    Nagy, K. L.; Schlegel, M. L.; Fenter, P.; Jacobsen, S. D.; Sturchio, N. C.; Cheng, L.

    2002-12-01

    Detrital phyllosilicates and clays are major sorbents for contaminants, natural organic matter, and nutrients in soils and sediments, yet our knowledge of sorption mechanisms is largely based on data obtained at the macroscopic scale. Synchrotron-based X-ray reflectivity is used to determine the structure of sorbates with respect to the mineral surface and, in contrast to X-ray Absorption Spectroscopic techniques, provides comparable information concerning the distribution of water. The unique ability to characterize water structure illuminates the inner-sphere or outer-sphere nature of sorbed cations. We used high-resolution in-situ X-ray reflectivity measurements at BESSRC-CAT, Advanced Photon Source, to characterize the sorption of K, Cs, Ca, and Ba from chloride solutions onto the basal surface of muscovite. X-ray reflectivity data were collected through the specular reflection condition and converted to electron density profiles perpendicular to the interface by applying atomistic structural models that included surface relaxation, sorbate concentration and position, water structure, and surface roughness. Cations were attached to the basal surface dominantly in the first adsorbed layer, which has the highest electron density of the solution phase. Derived heights above basal oxygens for K (1.67(6) \\x8F) and Cs (2.15(9) \\x8F) differ by the difference in their crystallographic radii and correspond closely to values in bulk K- and Cs-micas. Heights for Ca (2.5(1) \\x8F) and Ba (2.04(5) \\x8F) follow the trend for hydrated radii and deviate from the trend for crystallographic radii. All derived heights imply that no separate water layer exists between the sorbates and mineral surface. Interpretations of electron density profiles indicate the presence of cosorbed water or possibly, for divalent cations, cosorbed chloride. Water layering above the sorbed cation layer and minimal relaxation of the bulk muscovite were observed.

  1. Synchrotron radiation-based x-ray reflection and scattering techniques for dimensional nanometrology

    NASA Astrophysics Data System (ADS)

    Krumrey, Michael; Gleber, Gudrun; Scholze, Frank; Wernecke, Jan

    2011-09-01

    Nanoobjects have at least one dimension in the range from 1 to 100 nm. Thus, if radiation is used for dimensional metrology, it should preferably have a wavelength in or below this range. For example, x-ray reflectometry (XRR) using x-ray tubes with Cu Kα radiation is widely used for layer thickness measurements with relative uncertainties of about 1%. By using different monochromator beamlines in the laboratory of PTB at the synchrotron radiation facility BESSY II, any x-ray wavelength from several nanometers down to about 0.1 nm can be selected for dimensional measurements in the nanometer range. Here, XRR is performed at wavelengths in the vicinity of an absorption edge of the chemical elements involved in order to enhance the contrast for layer systems like SiO2/Si which are difficult to resolve with Cu Kα radiation. By using longer wavelengths of around 2 nm, even an oxide layer and a thin carbonaceous contamination layer on a strongly curved spherical surface were separated, as required for measurements at 95 mm diameter silicon spheres within the international Avogadro project for the new definition of the kilogram. For nanoparticles in suspension, small angle x-ray scattering (SAXS) is the method of choice for dimensional metrology. This ensemble technique requires intense, monochromatic x-rays of low divergence. From the scattering pattern, the particle diameter and the size distribution are obtained. Moreover, the dimensional properties of nanostructured surfaces and nanoparticles on surfaces have been studied by grazing incidence SAXS (GISAXS), combining small angle scattering with the reflection geometry known from XRR. The diameters of gold nanoparticles obtained by SAXS and GISAXS are in very good agreement.

  2. Direct Determination of Oxidation States of Uranium in Mixed-Valent Uranium Oxides Using Total Reflection X-ray Fluorescence X-ray Absorption Near-Edge Spectroscopy.

    PubMed

    Sanyal, Kaushik; Khooha, Ajay; Das, Gangadhar; Tiwari, M K; Misra, N L

    2017-01-03

    Total reflection X-ray fluorescence (TXRF)-based X-ray absorption near-edge spectroscopy has been used to determine the oxidation state of uranium in mixed-valent U3O8 and U3O7 uranium oxides. The TXRF spectra of the compounds were measured using variable X-ray energies in the vicinity of the U L3 edge in the TXRF excitation mode at the microfocus beamline of the Indus-2 synchrotron facility. The TXRF-based X-ray absorption near-edge spectroscopy (TXRF-XANES) spectra were deduced from the emission spectra measured using the energies below and above the U L3 edge in the XANES region. The data processing using TXRF-XANES spectra of U(IV), U(V), and U(VI) standard compounds revealed that U present in U3O8 is a mixture of U(V) and U(VI), whereas U in U3O7 is mixture of U(IV) and U(VI). The results obtained in this study are similar to that reported in literature using the U M edge. The present study has demonstrated the possibility of application of TXRF for the oxidation state determination and elemental speciation of radioactive substances in a nondestructive manner with very small amount of sample requirement.

  3. Trace elements determination in red and white wines using total-reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Anjos, M. J.; Lopes, R. T.; de Jesus, E. F. O.; Moreira, S.; Barroso, R. C.; Castro, C. R. F.

    2003-12-01

    Several wines produced in different regions from south of Brazil and available in markets in Rio de Janeiro were analyzed for their contents of elements such as: P, S, Cl, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb and Sr. Multi-element analysis was possible with simple sample preparation and subsequent analysis by total-reflection X-ray fluorescence using synchrotron radiation. The measurement was carried at the X-ray fluorescence beamline in the Synchrotron Light Source Laboratory in Campinas, Brazil. The levels of the various elements obtained were lower in the Brazilian wines than the values generally found in the literature. The present study indicates the capability of multi-element analysis for determining the contents of various elements present in wines coming from Brazil vineyards by using a simple, sensitive and precise method.

  4. Search for astrophysical rotating Ellis wormholes with x-ray reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Menglei; Cardenas-Avendano, Alejandro; Bambi, Cosimo; Kleihaus, Burkhard; Kunz, Jutta

    2016-07-01

    Recently, two of us have found numerically rotating Ellis wormholes as solutions of four-dimensional Einstein gravity coupled to a phantom field. In this paper, we investigate possible observational signatures to identify similar objects in the Universe. These symmetric wormholes have a mass and are compact, so they may look like black holes. We study the iron line profile in the x-ray reflection spectrum of a thin accretion disk around rotating Ellis wormholes and we find some specific observational signatures that can be used to distinguish these objects from Kerr black holes. We simulate some observations with XIS/Suzaku assuming typical parameters for a bright active galactic nucleus and we conclude that current x-ray missions cannot apply strong constraints.

  5. Microlensing Constraints on Quasar Spins and X-ray Reflection Regions

    NASA Astrophysics Data System (ADS)

    Dai, Xinyu

    2017-08-01

    Gravitational microlensing provides a unique probe of the innermost parts of quasar accretion disks, close to the event horizon of supermassive black holes. Using Chandra monitoring data of six lenses from two Large Programs in Cycles 11 and 14/15, we identified two microlensing effects that can be used to constrain black hole spins and X-ray reflection regions for high redshift quasars. The first effect is the excess iron line equivalent widths of lensed quasars compared to normal AGN, and the second is the distribution of iron line peak energies of lensed quasars. A microlensing analysis of the iron line equivalent widths prefers high spin values and very steep iron line emissivity profiles for quasars at z~2. We will also discuss the prospect of measuring quasar spins with microlensing using the next generation of X-ray telescopes.

  6. Magnified x-ray phase imaging using asymmetric Bragg reflection: Experiment and theory

    SciTech Connect

    Modregger, Peter; Schaefer, Peter; Koehler, Rolf; Luebbert, Daniel

    2006-08-01

    X-ray imaging using asymmetric Bragg reflection in the hard x-ray regime opens the way to improve the spatial resolution limit below 1 {mu}m by magnifying the image before detection, simultaneously providing a strong phase contrast. A theoretical formalism of the imaging process is established. Based on this algorithm, numerical simulations are performed and demonstrate that both Fresnel propagation and Bragg diffraction contribute to contrast formation. The achievable resolution of this technique is investigated theoretically; the results obtained can be used to improve future experimental setups. Furthermore, the minimum detectable phase gradient is estimated, for comparison with other phase sensitive imaging techniques. Results from biological objects demonstrate that the technique is viable for imaging both in two and three dimensions. Refraction contrast images are extracted from experimental projection images by an algorithm similar to diffraction-enhanced imaging (DEI), and used to achieve three-dimensional tomographic reconstruction.

  7. Total reflection X-ray spectrometry (TXRF) for trace elements assessment in edible clams.

    PubMed

    Marguí, Eva; de Fátima Marques, Alexandra; de Lurdes Prisal, Maria; Hidalgo, Manuela; Queralt, Ignasi; Carvalho, Maria Luisa

    2014-01-01

    The present contribution presents a preliminary investigation of the chemical composition with respect to major, minor, trace, and ultratrace elements in several clam species that are frequently used for human consumption in Portuguese markets and worldwide. In order to use a simple and rapid analytical methodology for clam analysis, energy dispersive X-ray fluorescence (EDXRF) spectrometry and total reflection X-ray fluorescence (TXRF) spectrometry were selected as analytical techniques. The analytical capabilities of TXRF spectrometry were evaluated for the determination of minor and trace elements in commercial edible clams. We compared the direct analysis of powdered suspensions (using different sample amounts and dispersant agents) with the analysis of the digested samples for trace element determination. Inductively coupled plasma mass spectrometry analysis of clam digests was also performed to evaluate the analytical possibilities of TXRF spectrometry for trace and ultratrace analysis.

  8. RASOR: an advanced instrument for soft x-ray reflectivity and diffraction.

    PubMed

    Beale, T A W; Hase, T P A; Iida, T; Endo, K; Steadman, P; Marshall, A R; Dhesi, S S; van der Laan, G; Hatton, P D

    2010-07-01

    We report the design and construction of a novel soft x-ray diffractometer installed at Diamond Light Source. The beamline endstation RASOR is constructed for general users and designed primarily for the study of single crystal diffraction and thin film reflectivity. The instrument is comprised of a limited three circle (theta, 2theta, and chi) diffractometer with an additional removable rotation (phi) stage. It is equipped with a liquid helium cryostat, and post-scatter polarization analysis. Motorized motions are provided for the precise positioning of the sample onto the diffractometer center of rotation, and for positioning the center of rotation onto the x-ray beam. The functions of the instrument have been tested at Diamond Light Source, and initial test measurements are provided, demonstrating the potential of the instrument.

  9. Configuration of membrane-bound proteins by x-ray reflectivity

    NASA Astrophysics Data System (ADS)

    Chen, Chiu-Hao; Málková, Šárka; Cho, Wonhwa; Schlossman, Mark L.

    2011-11-01

    In this presentation we review our recent work using x-ray reflectivity to determine the configuration of membrane-bound proteins. The reflectivity data is analyzed in terms of the known crystallographic structure of proteins and a slab model representing the lipid layer to yield an electron density profile of the lipid/protein system. Our recent modified analysis methodology for the lipid/protein system is concisely described in this report. In addition, some results of the configuration of the membrane-bound proteins cPLA2α-C2, p40phox-PX, and PKCα-C2 are highlighted.

  10. X-ray reflectivity study of formation of multilayer porous anodic oxides of silicon.

    SciTech Connect

    Chu, Y.; Fenollosa, R.; Parkhutik, V.; You, H.

    1999-07-21

    The paper reports data on the kinetics of anodic oxide films growth on silicon in aqueous solutions of phosphoric acids as well as a study of the morphology of the oxides grown in a special regime of the oscillating anodic potential. X-ray reflectivity measurements were performed on the samples of anodic oxides using an intense synchrotron radiation source. They have a multilayer structure as revealed by theoretical fitting of the reflectivity data. The oscillations of the anodic potential are explained in terms of synchronized oxidation/dissolution reactions at the silicon surface and accumulation of mechanic stress in the oxide film.

  11. Total reflection x-ray fluorescence: Determination of an optimum geometry

    SciTech Connect

    Koo, Y.M.; Chang, C.H.; Padmore, H.A.

    1997-04-01

    Total reflection X-Ray Fluorescence (TXRF) is a widely used technique in which the normal trace element detection capability of hard x-ray fluorescence (XRF) is enhanced by use of an x-ray reflective substrate. TXRF is more sensitive than normal photon induced XRF due to the reduction of the substrate scattering and fluorescence signals. This reduction comes about because in total external reflection, the photon field only penetrates about 20 {angstrom} into the surface, instead of typically 50 {mu}m for a silicon substrate at normal incidence for 10 KeV photons. The technique is used in many fields of trace element analysis, and is widely used in the determination of metal impurity concentrations on and in the surface of silicon wafers. The Semiconductor Industry Association roadmap (SIA) indicates a need for wafer contamination detection at the 10{sup 7}atoms/cm{sup 2} level in the next few years. Current commercial systems using rotating anode x-ray sources presently routinely operate with a sensitivity level of around 10{sup 10} atoms/cm{sup 2} and this has led to interest in the use of synchrotron radiation to extend the sensitivity by three orders of magnitude. The pioneering work of Pianetta and co-workers at SSRL has clearly shown that this should be possible, using a fully optimized source and detector. The purpose of this work is to determine whether ALS would be a suitable source for this type of highly sensitive wafer TXRF. At first look it appears improbable as the SSRL work used a high flux multipole wiggler source, and it is clear that the detected fluorescence for relevant concentrations is small. In addition, SSRL operates at 3.0 GeV rather than 1.9 GeV, and is therefore more naturally suited to hard x-ray experiments. The aim of this work was therefore to establish a theoretical model for the scattering and fluorescence processes, so that one could predict the differences between alternative geometries and select an optimum configuration.

  12. Simultaneous measurements of X-ray reflectivity and grazing incidence fluorescence at BL-16 beamline of Indus-2

    SciTech Connect

    Das, Gangadhar; Kane, S. R.; Khooha, Ajay; Singh, A. K.; Tiwari, M. K.

    2015-05-15

    A new multipurpose x-ray reflectometer station has been developed and augmented at the microfocus beamline (BL-16) of Indus-2 synchrotron radiation source to facilitate synchronous measurements of specular x-ray reflectivity and grazing incidence x-ray fluorescence emission from thin layered structures. The design and various salient features of the x-ray reflectometer are discussed. The performance of the reflectometer has been evaluated by analyzing several thin layered structures having different surface interface properties. The results reveal in-depth information for precise determination of surface and interface properties of thin layered materials demonstrating the immense potential of the combined measurements of x-ray reflectivity and grazing incidence fluorescence on a single reflectometer.

  13. Total reflection X-ray fluorescence spectrometers for multielement analysis: status of equipment

    NASA Astrophysics Data System (ADS)

    Ayala Jiménez, Rony E.

    2001-11-01

    Multielement analysis by total reflection X-ray fluorescence spectrometry has evolved during two decades. At present commercial equipment is available for chemical analysis of all types of biological and mineral samples. The electronic industry has also benefited from scientific and technological developments in this field due to new instrumentation to determine contamination on the surface of silicon wafers (the equipment will not be covered in this paper). The basic components of the spectrometers can be summarized as follows: (a) excitation source; (b) geometric arrangement (optics) for collimation and monochromatization of the primary radiation; (c) X-ray detector; and (d) software for operation of the instrument, data acquisition and spectral deconvolution to determine the concentrations of the elements (quantitative analysis). As an optional feature one manufacturer offers a conventional 45° geometry for direct excitation. Personal communications of the author and commercial brochures available have allowed us to list the components used in TXRF for multielement analysis. Excitation source: high-power sealed X-ray tubes, output from 1300 to 3000 W, different mixed alloy anodes Mo/W are used but molybdenum, tungsten and copper are common; single anode metal ceramic low power X-ray tubes, output up to 40 W. Excitation systems can be customized according to the requirements of the laboratory. Detector: silicon-lithium drifted semiconductor detector liquid nitrogen cooled; or silicon solid state thermoelectrically cooled detector (silicon drift detector SDD and silicon-PIN diode detector). Optics: multilayer monochromator of silicon-tungsten, nickel-carbon or double multilayer monochromator. Electronics: spectroscopy amplifier, analog to digital converter adapted to a PC compatible computer with software in a Windows environment for the whole operation of the spectrometer and for qualitative/quantitative analysis of samples are standard features in the

  14. Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions☆

    PubMed Central

    Ingerle, D.; Meirer, F.; Pepponi, G.; Demenev, E.; Giubertoni, D.; Wobrauschek, P.; Streli, C.

    2014-01-01

    The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and possible impurities. X-ray techniques utilizing the external reflection of X-rays are very surface sensitive, hence providing a non-destructive tool for process analysis and control. X-ray reflectometry (XRR) is an established technique for the characterization of single- and multi-layered thin film structures with layer thicknesses in the nanometer range. XRR spectra are acquired by varying the incident angle in the grazing incidence regime while measuring the specular reflected X-ray beam. The shape of the resulting angle-dependent curve is correlated to changes of the electron density in the sample, but does not provide direct information on the presence or distribution of chemical elements in the sample. Grazing Incidence XRF (GIXRF) measures the X-ray fluorescence induced by an X-ray beam incident under grazing angles. The resulting angle dependent intensity curves are correlated to the depth distribution and mass density of the elements in the sample. GIXRF provides information on contaminations, total implanted dose and to some extent on the depth of the dopant distribution, but is ambiguous with regard to the exact distribution function. Both techniques use similar measurement procedures and data evaluation strategies, i.e. optimization of a sample model by fitting measured and calculated angle curves. Moreover, the applied sample models can be derived from the same physical properties, like atomic scattering/form factors and elemental concentrations; a simultaneous analysis is therefore a straightforward approach. This combined analysis in turn reduces the uncertainties of the individual techniques, allowing a determination of dose and depth profile of the implanted

  15. Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions.

    PubMed

    Ingerle, D; Meirer, F; Pepponi, G; Demenev, E; Giubertoni, D; Wobrauschek, P; Streli, C

    2014-09-01

    The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and possible impurities. X-ray techniques utilizing the external reflection of X-rays are very surface sensitive, hence providing a non-destructive tool for process analysis and control. X-ray reflectometry (XRR) is an established technique for the characterization of single- and multi-layered thin film structures with layer thicknesses in the nanometer range. XRR spectra are acquired by varying the incident angle in the grazing incidence regime while measuring the specular reflected X-ray beam. The shape of the resulting angle-dependent curve is correlated to changes of the electron density in the sample, but does not provide direct information on the presence or distribution of chemical elements in the sample. Grazing Incidence XRF (GIXRF) measures the X-ray fluorescence induced by an X-ray beam incident under grazing angles. The resulting angle dependent intensity curves are correlated to the depth distribution and mass density of the elements in the sample. GIXRF provides information on contaminations, total implanted dose and to some extent on the depth of the dopant distribution, but is ambiguous with regard to the exact distribution function. Both techniques use similar measurement procedures and data evaluation strategies, i.e. optimization of a sample model by fitting measured and calculated angle curves. Moreover, the applied sample models can be derived from the same physical properties, like atomic scattering/form factors and elemental concentrations; a simultaneous analysis is therefore a straightforward approach. This combined analysis in turn reduces the uncertainties of the individual techniques, allowing a determination of dose and depth profile of the implanted

  16. Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions

    NASA Astrophysics Data System (ADS)

    Ingerle, D.; Meirer, F.; Pepponi, G.; Demenev, E.; Giubertoni, D.; Wobrauschek, P.; Streli, C.

    2014-09-01

    The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and possible impurities. X-ray techniques utilizing the external reflection of X-rays are very surface sensitive, hence providing a non-destructive tool for process analysis and control. X-ray reflectometry (XRR) is an established technique for the characterization of single- and multi-layered thin film structures with layer thicknesses in the nanometer range. XRR spectra are acquired by varying the incident angle in the grazing incidence regime while measuring the specular reflected X-ray beam. The shape of the resulting angle-dependent curve is correlated to changes of the electron density in the sample, but does not provide direct information on the presence or distribution of chemical elements in the sample. Grazing Incidence XRF (GIXRF) measures the X-ray fluorescence induced by an X-ray beam incident under grazing angles. The resulting angle dependent intensity curves are correlated to the depth distribution and mass density of the elements in the sample. GIXRF provides information on contaminations, total implanted dose and to some extent on the depth of the dopant distribution, but is ambiguous with regard to the exact distribution function. Both techniques use similar measurement procedures and data evaluation strategies, i.e. optimization of a sample model by fitting measured and calculated angle curves. Moreover, the applied sample models can be derived from the same physical properties, like atomic scattering/form factors and elemental concentrations; a simultaneous analysis is therefore a straightforward approach. This combined analysis in turn reduces the uncertainties of the individual techniques, allowing a determination of dose and depth profile of the implanted

  17. Determination of trace elements in Syrian medicinal plants and their infusions by energy dispersive X-ray fluorescence and total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Khuder, A.; Sawan, M. Kh.; Karjou, J.; Razouk, A. K.

    2009-07-01

    X-ray fluorescence (XRF) and total-reflection X-ray fluorescence (TXRF) techniques suited well for a multi-element determination of K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr in some Syrian medicinal plant species. The accuracy and the precision of both techniques were verified by analyzing the Standard Reference Materials (SRM) peach-1547 and apple leaves-1515. A good agreement between the measured concentrations of the previously mentioned elements and the certified values were obtained with errors less than 10.7% for TXRF and 15.8% for XRF. The determination of Br was acceptable only by XRF with an error less than 24%. Furthermore, the XRF method showed a very good applicability for the determination of K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, and Br in infusions of different Syrian medicinal plant species, namely anise ( Anisum vulgare), licorice root ( Glycyrrhiza glabra), and white wormwood ( Artemisia herba-alba).

  18. Reflectivity Around the Gold M-Edges of X-ray Reflector of the Soft X-Ray Telescope Onboard ASTRO-H

    NASA Technical Reports Server (NTRS)

    Kurashimaa, Sho; Furuzawa, Akihiro; Sato, Toshiki; Kikuchia, Naomichi; Nakaniwaa, Nozomi; Maeda, Yoshitomo; Ishida, Manabu; Izuka, Ryo; Okajima, Takashi; Mori, Hideyuki; hide

    2016-01-01

    The X-ray astronomy satellite ASTRO-H are equipped with two equivalent soft X-ray telescopes (SXT-I and SXT-S) which cover the energy band 0.3-12 keV. The X-ray reflectors of the SXTs are coated with a gold monolayer by means of the replication technique. A series of gold M absorption edges in the 2-4 keV band causes complex structures in the energy response of the SXTs. In the same band, there are astrophysically important emission lines from Si, Ar and S. Since the SXS has unprecedentedly high spectral resolution, we have measured the reflectivity around the gold M-edges in an extremely fine energy pitch at the synchrotron radiation facility KEK PF BL11-B, with the 2 eV pitch in 2100 eV to 4100 eV band that covers the entire series of the absorption edges (M-I through M-V) at grazing incident angles to the reflectors of 0.5, 0.8, 1.0, 1.2, 1.4 degree, and with a finer pitch of 0.25 eV in the 2200 eV to 2350 eV band where the two deepest M-IV and M-V edges are included. In the resultant reflectivity curves, we have clearly identified the fine structures associated with all the M-edges. Using these data, we calculated atomic scattering factor f1 as a function of X-ray energy, with which we have built the mirror response function which can be applied to the Suzaku spectra. As a result, we have found that discrepancy of the spectral model to the Suzaku data of 4U1630-472 (a black hole transient) and the Crab nebula around the M-edges are significantly reduced from those with the official Suzaku response.

  19. A new setup for high resolution fast X-ray reflectivity data acquisition

    NASA Astrophysics Data System (ADS)

    Lippmann, Milena; Buffet, Adeline; Pflaum, Kathrin; Ehnes, Anita; Ciobanu, Anca; Seeck, Oliver H.

    2016-11-01

    A new method for fast x-ray reflectivity data acquisition is presented. The method is based on a fast rotating, slightly tilted sample reflecting to a stationary mounted position sensitive detector and it allows for measurements of reflectivity curves in a quarter of a second. The resolution in q-space mainly depends on the beam properties and the pixel size of the detector. Maximum qz-value of 1 Å-1 can be achieved. The time-temperature depending structure changes of poly(N-isopropylacrylamide) thin films were investigated in situ by applying the fast-reflectivity setup. The results are presented in this paper as illustration of the method and proof of principle.

  20. General laws of X-ray reflection from rough surfaces: II. Conformal roughness

    NASA Astrophysics Data System (ADS)

    Kozhevnikov, I. V.

    2012-07-01

    Is shown that, if the expansions of the Debye-Waller formulas for the reflection and total scattering coefficients in the roughness height σ are limited to terms of order σ2, these expressions are valid for any layered inhomogeneous medium with conformal (depth-periodic) roughness and for any distribution function of the roughness heights if the roughness correlation length along the surface is sufficiently large. The advantages of measuring the total reflection coefficient, which characterizes the total intensity of radiation (both specularly reflected and diffusively scattered) directed by a rough surface back into vacuum, for solving the inverse problem of X-ray reflectometry (i.e., the reconstruction of the permittivity profile from a measured reflection curve) are discussed.

  1. Rethinking X-Ray and Neutron Reflection from Rough, Sharp Surfaces

    NASA Astrophysics Data System (ADS)

    Hussey, Daniel; Baxter, David; Snow, W. Michael

    2004-03-01

    We have developed an alternate method for analyzing the reflection of x-rays and thermal neutrons from rough, sharp interfaces. The method relies on the surface being locally flat, which implies a well-defined local surface normal whose direction deviates from the average surface normal. The surface's statistical properties, namely the r.m.s. roughness, σ and lateral correlation length, ξ, determine the distribution of the angle of the local surface normal. An experimentally verifiable consequence of this formulation of the reflection problem is that the angle of the reflected beam deviates from that of the incident beam, θi neq θ_r. The magnitude of this deviation is related to the surface's σ and ξ, as well as the angle of incidence. We will present a brief sketch of the analysis method, and compare the predictions with reflectivity measurements from thin metallic films grown on Si substrates.

  2. Three-Dimensional X-ray Reflections from Anthracite and Meta-Anthracite.

    PubMed

    Ergun, S; Mentser, M; O'donnell, H J

    1960-11-04

    Careful analysis of x-ray scattering intensities of demineralized metaanthracites and high-rank anthracites formed during the Pennsylvanian geological period has revealed the presence of three-dimensional (hkl) reflections of graphite, demonstrating unequivocally that coals graphitize with metamorphism. Graphitization has been observed also with a coal formed before the Cambrian period, much earlier than most coals. A significant degree of graphitization occurs by coalification when the graphite-like layers attain a size of 25 to 30 angstroms as compared to 100 A or more by the heat treatment of amorphous carbons.

  3. Synchrotron total reflection X-ray fluorescence at BL-16 microfocus beamline of Indus-2

    SciTech Connect

    Tiwari, M. K. Singh, A. K. Das, Gangadhar Chowdhury, Anupam Lodha, G. S.

    2014-04-24

    Determination of ultra trace elements is important in many disciplines both in basic and applied sciences. Numerous applications show their importance in medical science, environmental science, materials science, food processing and semiconductor industries and in maintaining the quality control of ultra pure chemicals and reagents. We report commissioning of a synchrotron based total reflection x-ray fluorescence (TXRF) facility on the BL-16 microfocus beamline of Indus-2. This paper describes the performance of the BL-16 TXRF spectrometer and the detailed description of its capabilities through examples of measured results.

  4. Synchrotron total reflection X-ray fluorescence at BL-16 microfocus beamline of Indus-2

    NASA Astrophysics Data System (ADS)

    Tiwari, M. K.; Singh, A. K.; Das, Gangadhar; Chowdhury, Anupam; Lodha, G. S.

    2014-04-01

    Determination of ultra trace elements is important in many disciplines both in basic and applied sciences. Numerous applications show their importance in medical science, environmental science, materials science, food processing and semiconductor industries and in maintaining the quality control of ultra pure chemicals and reagents. We report commissioning of a synchrotron based total reflection x-ray fluorescence (TXRF) facility on the BL-16 microfocus beamline of Indus-2. This paper describes the performance of the BL-16 TXRF spectrometer and the detailed description of its capabilities through examples of measured results.

  5. Non-null full field X-ray mirror metrology using SCOTS: a reflection deflectometry approach.

    PubMed

    Su, Peng; Wang, Yuhao; Burge, James H; Kaznatcheev, Konstantine; Idir, Mourad

    2012-05-21

    In a previous paper, the University of Arizona (UA) has developed a measurement technique called: Software Configurable Optical Test System (SCOTS) based on the principle of reflection deflectometry. In this paper, we present results of this very efficient optical metrology method applied to the metrology of X-ray mirrors. We used this technique to measure surface slope errors with precision and accuracy better than 100 nrad (rms) and ~200 nrad (rms), respectively, with a lateral resolution of few mm or less. We present results of the calibration of the metrology systems, discuss their accuracy and address the precision in measuring a spherical mirror.

  6. Structure of two-component lipid membranes on solid support: An x-ray reflectivity study

    SciTech Connect

    Novakova, Eva; Giewekemeyer, Klaus; Salditt, Tim

    2006-11-15

    We report an x-ray reflectivity study of phospholipid membranes deposited on silicon by vesicle fusion. The samples investigated were composed of single phospholipid bilayers as well as two-component lipid bilayer systems with varied charge density. We show that the resolution obtained in the density profile across the bilayer is high enough to distinguish two head-group maxima in the profile if the sample is in the phase coexistence regime. The water layer between the bilayer and silicon is found to depend on the lipid surface charge density.

  7. Non-null full field X-ray mirror metrology using SCOTS: a reflection deflectometry approach

    SciTech Connect

    Su P.; Kaznatcheev K.; Wang, Y.; Burge, J.H.; Idir, M.

    2012-05-16

    In a previous paper, the University of Arizona (UA) has developed a measurement technique called: Software Configurable Optical Test System (SCOTS) based on the principle of reflection deflectometry. In this paper, we present results of this very efficient optical metrology method applied to the metrology of X-ray mirrors. We used this technique to measure surface slope errors with precision and accuracy better than 100 nrad (rms) and {approx}200 nrad (rms), respectively, with a lateral resolution of few mm or less. We present results of the calibration of the metrology systems, discuss their accuracy and address the precision in measuring a spherical mirror.

  8. First Total Reflection X-Ray Fluorescence round-robin test of water samples: Preliminary results

    NASA Astrophysics Data System (ADS)

    Borgese, Laura; Bilo, Fabjola; Tsuji, Kouichi; Fernández-Ruiz, Ramón; Margui, Eva; Streli, Christina; Pepponi, Giancarlo; Stosnach, Hagen; Yamada, Takashi; Vandenabeele, Peter; Maina, David M.; Gatari, Michael; Shepherd, Keith D.; Towett, Erick K.; Bennun, Leonardo; Custo, Graciela; Vasquez, Cristina; Depero, Laura E.

    2014-11-01

    Total Reflection X-Ray Fluorescence (TXRF) is a mature technique to evaluate quantitatively the elemental composition of liquid samples deposited on clean and well polished reflectors. In this paper the results of the first worldwide TXRF round-robin test of water samples, involving 18 laboratories in 10 countries are presented and discussed. The test was performed within the framework of the VAMAS project, interlaboratory comparison of TXRF spectroscopy for environmental analysis, whose aim is to develop guidelines and a standard methodology for biological and environmental analysis by means of the TXRF analytical technique.

  9. Characterization of HgI/sub 2/ single crystals and detectors by x-ray rocking curve analysis and x-ray reflection topography

    SciTech Connect

    Ostrom, R.; Keller, L.; Wagner, N.J.; Schieber, M.M.; Ortale, C.; van den Berg, L.; Schnepple, W.F.

    1987-01-01

    An attempt has been made to establish a correlation between the results of x-ray rocking curves and x-ray reflection topographs for vapor grown HgI/sub 2/, single crystals. X-ray rocking curves were obtained by double crystal spectroscopy with Si as the first crystal and topographs were produced using the Berg-Barrett technique with an asymmetrically cut Si-disperser. The crystals were evaluated at different stages of detector preparation, i.e., cutting, polishing, etching, and deposition of contact. Multiple diffraction peaks could be observed as being indicative of small angle grain boundaries of up to 2/degree/. Definite nonuniformities on virgin single crystals as well as on detector crystals were observed by both methods. The crystal surface quality as assessed by these methods were used as a criterion to verify detector performance rating. No drastic improvement of surface quality on space grown crystals was indicated by these techniques. Efforts have also been devoted to determine intrinsic full width at half maximum of HgI/sub 2/ crystal for the crystallographic direction studied. 16 refs., 22 figs.

  10. Probing the clumping structure of giant molecular clouds through the spectrum, polarisation and morphology of X-ray reflection nebulae

    NASA Astrophysics Data System (ADS)

    Molaro, Margherita; Khatri, Rishi; Sunyaev, Rashid A.

    2016-05-01

    We introduce a new method for probing global properties of clump populations in giant molecular clouds (GMCs) in the case where these act as X-ray reflection nebulae (XRNe), based on the study of the clumping's overall effect on the reflected X-ray signal, in particular on the Fe K-α line's shoulder. We consider the particular case of Sgr B2, one of the brightest and most massive XRN in the Galactic center (GC) region. We parametrise the gas distribution inside the cloud using a simple clumping model with theslope of the clump mass function (α), the minimum clump mass (mmin), the fraction of the cloud's mass contained in clumps (fDGMF), and the mass-size relation of individual clumps as free parameters, and investigate how these affect the reflected X-ray spectrum. In the case of very dense clumps, similar to those presently observed in Sgr B2, these occupy a small volume of the cloud and present a small projected area to the incoming X-ray radiation. We find that these contribute negligibly to the scattered X-rays. Clump populations with volume-filling factors of >10-3 do leave observational signatures, that are sensitive to the clump model parameters, in the reflected spectrum and polarisation. Future high angular resolution X-ray observations could therefore complement the traditional optical and radio observations of these GMCs, and prove to be a powerful probe in the study of their internal structure. Clumps in GMCs should further be visible both as bright spots and regions of heavy absorption in high resolution X-ray observations. We therefore also study the time-evolution of the X-ray morphology, under illumination by a transient source, as a probe of the 3D distribution and column density of individual clumps by future X-ray observatories.

  11. Reflection thermal diffuse x-ray scattering for quantitative determination of phonon dispersion relations

    NASA Astrophysics Data System (ADS)

    Mei, A. B.; Hellman, O.; Schlepütz, C. M.; Rockett, A.; Chiang, T.-C.; Hultman, L.; Petrov, I.; Greene, J. E.

    2015-11-01

    Synchrotron reflection x-ray thermal diffuse scattering (TDS) measurements, rather than previously reported transmission TDS, are carried out at room temperature and analyzed using a formalism based upon second-order interatomic force constants and long-range Coulomb interactions to obtain quantitative determinations of MgO phonon dispersion relations ℏ ωj (q), phonon densities of states g (ℏ ω ), and isochoric temperature-dependent vibrational heat capacities cv(T ) . We use MgO as a model system for investigating reflection TDS due to its harmonic behavior as well as its mechanical and dynamic stability. Resulting phonon dispersion relations and densities of states are found to be in good agreement with independent reports from inelastic neutron and x-ray scattering experiments. Temperature-dependent isochoric heat capacities cv(T ) , computed within the harmonic approximation from ℏ ωj (q) values, increase with temperature from 0.4 ×10-4eV /atom K at 100 K to 1.4 ×10-4eV /atom K at 200 K and 1.9 ×10-4eV /atom K at 300 K, in excellent agreement with isobaric heat capacity values cp(T ) between 4 and 300 K. We anticipate that the experimental approach developed here will be valuable for determining vibrational properties of heteroepitaxial thin films since the use of grazing-incidence (θ ≲θc , where θc is the density-dependent critical angle) allows selective tuning of x-ray penetration depths to ≲10 nm .

  12. Reflection thermal diffuse x-ray scattering for quantitative determination of phonon dispersion relations

    SciTech Connect

    Mei, A. B.; Hellman, O.; Schlepuetz, C. M.; Rockett, A.; Chiang, T. -C.; Hultman, L.; Petrov, I.; Greene, J. E.

    2015-11-03

    Synchrotron reflection x-ray thermal diffuse scattering (TDS) measurements, rather than previously reported transmission TDS, are carried out at room temperature and analyzed using a formalism based upon second-order interatomic force constants and long-range Coulomb interactions to obtain quantitative determinations of MgO phonon dispersion relations (h) over bar omega(j) (q), phonon densities of states g((h) over bar omega), and isochoric temperature-dependent vibrational heat capacities cv (T). We use MgO as a model system for investigating reflection TDS due to its harmonic behavior as well as its mechanical and dynamic stability. Resulting phonon dispersion relations and densities of states are found to be in good agreement with independent reports from inelastic neutron and x-ray scattering experiments. Temperature-dependent isochoric heat capacities cv (T), computed within the harmonic approximation from (h) over bar omega(j) (q) values, increase with temperature from 0.4 x 10-4 eV/atom K at 100 K to 1.4 x 10-4 eV/atom K at 200 K and 1.9 x 10-4 eV/atom K at 300 K, in excellent agreement with isobaric heat capacity values cp (T) between 4 and 300 K. We anticipate that the experimental approach developed here will be valuable for determining vibrational properties of heteroepitaxial thin films since the use of grazing-incidence (θ ≲ θc where θc is the density-dependent critical angle) allows selective tuning of x-ray penetration depths to ≲ 10 nm.

  13. Reflection thermal diffuse x-ray scattering for quantitative determination of phonon dispersion relations

    DOE PAGES

    Mei, A. B.; Hellman, O.; Schlepuetz, C. M.; ...

    2015-11-03

    Synchrotron reflection x-ray thermal diffuse scattering (TDS) measurements, rather than previously reported transmission TDS, are carried out at room temperature and analyzed using a formalism based upon second-order interatomic force constants and long-range Coulomb interactions to obtain quantitative determinations of MgO phonon dispersion relations (h) over bar omega(j) (q), phonon densities of states g((h) over bar omega), and isochoric temperature-dependent vibrational heat capacities cv (T). We use MgO as a model system for investigating reflection TDS due to its harmonic behavior as well as its mechanical and dynamic stability. Resulting phonon dispersion relations and densities of states are found tomore » be in good agreement with independent reports from inelastic neutron and x-ray scattering experiments. Temperature-dependent isochoric heat capacities cv (T), computed within the harmonic approximation from (h) over bar omega(j) (q) values, increase with temperature from 0.4 x 10-4 eV/atom K at 100 K to 1.4 x 10-4 eV/atom K at 200 K and 1.9 x 10-4 eV/atom K at 300 K, in excellent agreement with isobaric heat capacity values cp (T) between 4 and 300 K. We anticipate that the experimental approach developed here will be valuable for determining vibrational properties of heteroepitaxial thin films since the use of grazing-incidence (θ ≲ θc where θc is the density-dependent critical angle) allows selective tuning of x-ray penetration depths to ≲ 10 nm.« less

  14. Integrated reflectivity measurements of hydrogen phthalate crystals for high-resolution soft x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Zastrau, U.; Förster, E.

    2014-09-01

    The integrated x-ray reflectivity of Potassium Hydrogen Phthalate (KAP) and Rubidium Hydrogen Phthalate (RAP) crystals is studied at a photon energy of (1740±14) eV using a double-crystal setup. The absolute measured reflectivities are in < 5% agreement with the values predicted by the dynamic diffraction theory for perfect crystals when absorption is included. Within 4% experimental error margins, specimen that were exposed to ambient conditions over many years show identical reflectivity as specimen that were cleaved just before the measurement. No differences are observed between cleaving off a 10 μm surface layer and splitting the entire crystal bulk of 2 mm thickness. We conclude that at 1.7 keV photon energy the penetration depth of ~ 1 μm is large compared to a potentially deteriorated surface layer of a few 10 nm.

  15. Full Polarization Analysis of Resonant Superlattice and Forbidden x-ray Reflections in Magnetite

    SciTech Connect

    Wilkins, S.B.; Bland, S.R.; Detlefs, B.; Beale, T.A.W.; Mazzoli, C.; Joly, Y.; Hatton, P.D.; Lorenzo, J.E.; Brabers, V.A.M.

    2009-12-02

    Despite being one of the oldest known magnetic materials, and the classic mixed valence compound, thought to be charge ordered, the structure of magnetite below the Verwey transition is complex and the presence and role of charge order is still being debated. Here, we present resonant x-ray diffraction data at the iron K-edge on forbidden (0, 0, 2n+1){sub C} and superlattice (0, 0, 2n+1/2)C reflections. Full linear polarization analysis of the incident and scattered light was conducted in order to explore the origins of the reflections. Through simulation of the resonant spectra we have confirmed that a degree of charge ordering takes place, while the anisotropic tensor of susceptibility scattering is responsible for the superlattice reflections below the Verwey transition. We also report the surprising result of the conversion of a significant proportion of the scattered light from linear to nonlinear polarization.

  16. Reflection Imaging X-Ray Laser Microscope (RIXRALM) and its biological applications. Progress report

    SciTech Connect

    Suckewer, S.

    1998-07-01

    The main stimulus for the development of the proposed microscope (RIXRALM) is the possibility to view the surface and near surface structure of biological materials, such as cell membranes at much higher resolution than an optical (confocal) microscope. Although the prediction resolution of RIXRALM was lower than a Scanning Electron Microscope (SEM), the possibility to obtain images of cells (membranes) in a more natural, hydrated state and, in many cases, without staining, made the idea of a reflection X-ray microscope very attractive. The specimen can be in an H{sub 2}O saturated He atmosphere at atmospheric pressure. As the image can be obtained quickly (nsec exposure, occurring within seconds of insertion into such an environment), the cell surface can be seen in a state which is very close to its natural condition. Besides, the short exposure time eliminates the effect of motional blurring on the images. Their X-ray reflection microscope fit well in the very large gap in the size of biological objects studied in light microscopy (sub-micron size) and electron microscope (down to a few nanometers size).

  17. A REFLECTION MODEL FOR THE CYCLOTRON LINES IN THE SPECTRA OF X-RAY PULSARS

    SciTech Connect

    Poutanen, Juri; Mushtukov, Alexander A.; Tsygankov, Sergey S.; Nagirner, Dmitrij I.; Suleimanov, Valery F.; Doroshenko, Victor; Lutovinov, Alexander A.

    2013-11-10

    Cyclotron resonance scattering features observed in the spectra of some X-ray pulsars show significant changes of the line energy with the pulsar luminosity. At high luminosities, these variations are often associated with the onset and growth of the accretion column, which is believed to be the origin of the observed emission and of the cyclotron lines. However, this scenario inevitably implies a large gradient of the magnetic field strength within the line-forming region, which makes the formation of the observed line-like features problematic. Moreover, the observed variation of the cyclotron line energy is much smaller than could be anticipated for the corresponding luminosity changes. We argue here that a more physically realistic situation is that the cyclotron line forms when the radiation emitted by the accretion column is reflected from the neutron star surface, where the gradient of the magnetic field strength is significantly smaller. Here we develop a reflection model and apply it to explain the observed variations of the cyclotron line energy in a bright X-ray pulsar V 0332+53 over a wide range of luminosities.

  18. Synchrotron x-ray reflectivity study of oxidation/passivation of copper and silicon.

    SciTech Connect

    Chu, Y.; Nagy, Z.; Parkhutik, V.; You, H.

    1999-07-21

    Synchrotron x-ray-scattering technique studies of copper and silicon electrochemical interfaces are reported. These two examples illustrate the application of synchrotron x-ray techniques for oxidation, passivation, and dissolution of metals and semiconductors.

  19. X-ray specular reflection studies of silicon coated by organic monolayers (alkylsiloxanes)

    NASA Astrophysics Data System (ADS)

    Tidswell, I. M.; Ocko, B. M.; Pershan, P. S.; Wasserman, S. R.; Whitesides, G. M.; Axe, J. D.

    1990-01-01

    X-ray specular reflectivity has been used to characterize the structure of silicon-silicon-oxide surfaces coated with chemisorbed hydrocarbon monolayer films (alkylsiloxanes). Using synchrotron radiation the reflectivity was followed over 9 orders of magnitude, from grazing incidence to an incident angle of φ~=6.5°, or q=(4π/λ)sin(φ)=0.8 Å-1, allowing a spatial resolution of features approximately π/0.8~=4.0 Å along the surface normal. Analysis was performed by fitting the data to reflectivities calculated from models of the surface electron density and by calculating Patterson functions directly from the data. Although the measured reflectivities could be equally well described by different sets of model parameters, the electron densities calculated from these different parameters were remarkably alike. Inspection of the electron densities allowed identification of a layer of SiO2 (~=17-Å thick), a layer of head-group region where the alkylsiloxane adsorbs to the SiO2, and the hydrocarbon layer. Fitting the data also required that the various interfaces have different widths. The fact that the same local hydrocarbon density of 0.85 g/cm3 was observed for both fully formed and partially formed monolayers with alkane chains of varying length excluded a model in which the partially formed monolayer was made up of separated islands of well-formed monolayers. Measurements before and after chemical reaction of a monolayer in which the alkyl chain was terminated by an olefinic group demonstrated the ability to use x-ray reflectivity to characterize chemical changes. The effects of radiation damage on these types of measurements are described.

  20. Achromatic and high-resolution full-field X-ray microscopy based on total-reflection mirrors.

    PubMed

    Matsuyama, Satoshi; Emi, Yoji; Kino, Hidetoshi; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2015-04-20

    We developed an achromatic and high-resolution full-field X-ray microscope based on advanced Kirkpatrick-Baez mirror optics that comprises two pairs of elliptical mirrors and hyperbolic mirrors utilizing the total reflection of X-rays. Performance tests to investigate the spatial resolution and chromatic aberration were performed at SPring-8. The microscope clearly resolved the pattern with ~100-nm feature size. Imaging the pattern by changing the X-ray energy revealed achromatism in the wide energy range of 8-11 keV.

  1. Depth-dependent non-destructive analysis of thin overlayers using total-reflection-angle X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Shibata, Noriyoshi; Okubo, Soichiro; Yonemitsu, Kyoko

    1996-07-01

    Electron-beam excited X-ray chemical analysis with very small angle condition has been applied to measure thin overlayers on substrates. Relations between the fluorescent X-ray intensity and the emission angle is investigated based on a model. It is demonstrated that the emission-angle dependence of the X-ray intensity is sensitively reflected by film thickness and layer structure. The calculations agreed well with experiments for thin Au and Pd multilayers on Si substrate. The results show that this method is applicable to a non-destructive depth profiling of chemical compositions.

  2. Multiple-wave diffraction in high energy resolution back-reflecting x-ray optics.

    PubMed

    Stetsko, Yuri P; Keister, J W; Coburn, D S; Kodituwakku, C N; Cunsolo, A; Cai, Y Q

    2011-10-07

    We have studied the effects of multiple-wave diffraction in a novel optical scheme recently published by Shvyd'ko et al. utilizing Bragg diffraction of x rays in backscattering geometry from asymmetrically cut crystals for achieving energy resolutions beyond the intrinsic width of the Bragg reflection. By numerical simulations based on dynamic x-ray diffraction and by experimentation involving two-dimensional angular scans of the back-reflecting crystal, multiple-wave diffraction was found to contribute up to several tens percent loss of efficiency but can be avoided without degrading the energy resolution of the original scheme by careful choice of azimuthal orientation of the diffracting crystal surface and by tilting of the crystal perpendicular to the dispersion plane.

  3. Modelless approach in X-ray reflectivity of multilayer nanoheterostructure Fe/Cr

    NASA Astrophysics Data System (ADS)

    Babanov, Yu A.; Devyaterikov, D. I.; Ustinov, V. V.

    2017-10-01

    A new modelless method of determining the element concentration profile of metallic multilayer nanoheterostructures for low-contrast systems is applied to study periodical and aperiodical multilayer Fe/Cr system by X-ray reflectivity. As a special case, we discuss a cluster-layered Fe/Cr film with Kondo-like behavior of the resistance. The method does not require any a priori information on the structure of the multilayer nanostructures, such as position and width of interfaces, as well as, their shape. The method is based on solution of the Fredholm integral equation of the first kind, which relates the reflection coefficient and the concentration profile of the chemical elements of the sample. The ill-posed inverse problem of determination of the element concentration profile is solved by the regularization method. Efficiency of the method is confirmed by model calculations.

  4. Elemental concentration analysis in prostate tissues using total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Leitão, R. G.; Palumbo, A.; Souza, P. A. V. R.; Pereira, G. R.; Canellas, C. G. L.; Anjos, M. J.; Nasciutti, L. E.; Lopes, R. T.

    2014-02-01

    Prostate cancer (PCa) currently represents the second most prevalent malignant neoplasia in men, representing 21% of all cancer cases. Benign Prostate Hyperplasia (BPH) is an illness prevailing in men above the age of 50, close to 90% after the age of 80. The prostate presents a high zinc concentration, about 10-fold higher than any other body tissue. In this work, samples of human prostate tissues with cancer, BPH and normal tissue were analyzed utilizing total reflection X-ray fluorescence spectroscopy using synchrotron radiation technique (SR-TXRF) to investigate the differences in the elemental concentrations in these tissues. SR-TXRF analyses were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, São Paulo. It was possible to determine the concentrations of the following elements: P, S, K, Ca, Fe, Cu, Zn and Rb. By using Mann-Whitney U test it was observed that almost all elements presented concentrations with significant differences (α=0.05) between the groups studied.

  5. X-ray reflectivity and diffuse studies of lipid bilayer stacks on solid substrates

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Mukhopadhyay, M.; Ma, Y.; Sinha, Sunil K.; Decaro, C.; Berry, J.; Lurio, Laurence B.; Jiang, Z.; Brozell, A.; Bricarello, D.; Parikh, Atul N.

    2010-03-01

    Recently, major efforts have been made to study model lipid membranes supported on a solid substrate. A typical bilayer is characterized by its static structure and dynamic thermal fluctuations which are described by three physical quantities, the bending modulus, the surface tension, and the external potential due to a nearby surface or neighboring bilayers. The solid substrate affects both the static and dynamic behaviors of the bilayer deposited on its top. We have carried out a systematic study of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) bilayer stacks up to five bilayers prepared with Langmuir-Blodgett (LB) and Langmuir-Schaeffer (LS) methods. A complete picture of the static bilayer structure, both in-plane and out of plane, and the dynamic fluctuations as a function of temperature and the number of stacks, i.e., the distance from the substrate, is obtained with x-ray reflectivity, Grazing Incidence Small Angle X-ray Scattering (GISAXS), and rocking scans. (Work supported by NSF, DMR0706369)

  6. Total reflection X-ray fluorescence (TXRF) for direct analysis of aerosol particle samples.

    PubMed

    Bontempi, E; Zacco, A; Benedetti, D; Borgese, L; Colombi, P; Stosnach, H; Finzi, G; Apostoli, P; Buttini, P; Depero, L E

    2010-04-14

    Atmospheric aerosol particles have a great impact on the environment and on human health. Routine analysis of the particles usually involves only the mass determination. However, chemical composition and phases provide fundamental information about the particles' origins and can help to prevent health risks. For example, these particles may contain heavy metals such as Pb, Ni and Cd, which can adversely affect human health. In this work, filter samples were collected in Brescia, an industrial town located in Northern Italy. In order to identify the chemical composition and the phases of the atmospheric aerosols, the samples were analysed by means of total reflection X-ray fluorescence (TXRF) spectrometry with a laboratory instrument and X-ray microdiffraction at Synchrotron Daresbury Laboratories, Warrington (Cheshire, UK). The results are discussed and correlated to identify possible pollution sources. The novelty of this analytical approach is that filter samples for TXRF were analysed directly and did not require chemical pretreatment to leach elements from the aerosol particulates. The results of this study clearly show that TXRF is a powerful technique for the analysis of atmospheric aerosols on 'as-received' filters, thereby leaving samples intact and unaltered for possible subsequent analyses by other methods. In addition, the low detection limits for many elements (low ng/cm2) indicate that this method may hold promise in various application fields, such as nanotechnology.

  7. X-ray reflectivity analysis of titanium dioxide thin films grown by cathodic arc deposition.

    PubMed

    Kleiman, A; Lamas, D G; Craievich, A F; Márquez, A

    2014-05-01

    TiO2 thin films deposited by a vacuum arc on a glass substrate were characterized by X-ray reflectivity (XRR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Several thin films with different amounts of deposited TiO2 mass and different deposition and annealing temperatures were studied. A qualitative analysis of the XRD patterns indicated the presence of the anatase and/or rutile crystalline phases in most of the studied samples. From the analysis of the experimental XRR curves--which exhibited a wide angular range of oscillatory behavior--the thickness, mass density and interface roughness were determined. All XRR patterns were well fitted by modeled curves that assume the presence of a single and homogeneous TiO2 layer over which a very thin H2O layer is adsorbed. The thickest H2O adsorption layers were developed in films with the highest anatase content. Our overall results of the XRR analyses are consistent with those derived from the imaging techniques (SEM and AFM).

  8. Determination of carbon in natural freshwater biofilms with total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Óvári, M.; Streli, C.; Wobrauschek, P.; Záray, Gy.

    2009-08-01

    There is a growing interest in determination of low Z elements, i.e., carbon to phosphorus, in biological samples. Total reflection X-ray fluorescence spectrometry (TXRF) has been already established as suitable trace element analytical method with low sample demand and quite good quantification limits. Recently, the determinable element range was extended towards Z = 6 (carbon). Biofilms can be used for biomonioring purposes in the aquatic environment. Besides the trace metals, especially the determination of the carbon content is important for the better understanding of the early stage of biofilm formation. For this, an ATI low Z spectrometer equipped with Cr-anode X-ray tube, multilayer monochromator, vacuum chamber, and a Si(Li) detector with ultra thin window was used. Biofilms were grown on two different artificial supports (granite and plexiglass), freeze dried, suspended in high purity water and analyzed. As an internal standard the natural titanium content of the biofilms was used. The accuracy of the method was checked by total carbon measurement using a combusting carbon analyzer.

  9. Impulsive solar X-ray bursts. 4: Polarization, directivity and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    NASA Technical Reports Server (NTRS)

    Langer, S. H.; Petrosian, V.

    1976-01-01

    A Monte Carlo method is described for evaluation of the spectrum, directivity and polarization of X-rays diffusely reflected from stellar photospheres. the accuracy of the technique is evaluated through comparison with analytic results. Using the characteristics of the incident X-rays of the model for solar X-ray flares, the spectrum, directivity and polarization of the reflected and the total X-ray fluxes are evaluated. The results are compared with observations.

  10. Total reflection X-ray fluorescence and energy-dispersive X-ray fluorescence analysis of runoff water and vegetation from abandoned mining of Pb Zn ores

    NASA Astrophysics Data System (ADS)

    Marques, A. F.; Queralt, I.; Carvalho, M. L.; Bordalo, M.

    2003-12-01

    The present work reports on the heavy metal content: Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb in running waters and vegetation around abandoned mining areas. Two species of mosses ( Dicranum sp. and Pleurocarpus sp.) and three different species of wild grass ( Bromus sp., Rumex sp. and Pseudoavena sp.) growing on the surrounding areas of old lead-zinc mines (Aran Valley, Pyrenees, NE Spain) have been analyzed. Both water and vegetation were collected in two different sampling places: (a) near the mine gallery water outlets and (b) on the landfill close to the abandoned mineral concentration factories. For the heavy metal content determination, two different techniques were used: total reflection X-ray fluorescence for water analysis and energy-dispersive X-ray fluorescence for vegetation study. Surface waters around mine outlets exhibit anomalous content of Co, Ni, Zn, Cd. Stream waters running on mining landfills exhibit higher Cu, Zn, Cd and Pb than those of the waters at the mine gallery outlets. The results allow us to assess the extent of the environmental impact of the mining activities on the water quality. The intake of these elements by vegetation was related with the sampling place, reflecting the metal water content and the substrate chemistry. Accumulation of metals in mosses is higher than those exhibited in wild grasses. Furthermore, different levels of accumulation were found in different wild grass. Rumex sp. presented the lowest metal concentrations, while Pseudoavena sp. reported the highest metal content.

  11. A setup for synchrotron-radiation-induced total reflection X-ray fluorescence and X-ray absorption near-edge structure recently commissioned at BESSY II BAMline.

    PubMed

    Fittschen, U; Guilherme, A; Böttger, S; Rosenberg, D; Menzel, M; Jansen, W; Busker, M; Gotlib, Z P; Radtke, M; Riesemeier, H; Wobrauschek, P; Streli, C

    2016-05-01

    An automatic sample changer chamber for total reflection X-ray fluorescence (TXRF) and X-ray absorption near-edge structure (XANES) analysis in TXRF geometry was successfully set up at the BAMline at BESSY II. TXRF and TXRF-XANES are valuable tools for elemental determination and speciation, especially where sample amounts are limited (<1 mg) and concentrations are low (ng ml(-1) to µg ml(-1)). TXRF requires a well defined geometry regarding the reflecting surface of a sample carrier and the synchrotron beam. The newly installed chamber allows for reliable sample positioning, remote sample changing and evacuation of the fluorescence beam path. The chamber was successfully used showing accurate determination of elemental amounts in the certified reference material NIST water 1640. Low limits of detection of less than 100 fg absolute (10 pg ml(-1)) for Ni were found. TXRF-XANES on different Re species was applied. An unknown species of Re was found to be Re in the +7 oxidation state.

  12. Reflectivity around the gold L-edges of x-ray reflector of the soft x-ray telescope onboard ASTRO-H

    NASA Astrophysics Data System (ADS)

    Maeda, Yoshitomo; Kikuchi, Naomichi; Kurashima, Sho; Ishida, Manabu; Iizuka, Ryo; Hayashi, Takayuki; Okajima, Takashi; Matsumoto, Hironori; Mitsuishi, Ikuyuki; Saji, Shigetaka; Sato, Toshiki; Tachibana, Sasagu; Mori, Hideyuki; Christensen, Finn; Brejnholt, Nicolai; Nitta, Kiyofumi; Uruga, Tomoya

    2016-07-01

    We report the atomic scattering factor in the 11.2{15.4 keV for the ASTRO-H Soft X-ray Telescope (SXT)9 obtained in the ground based measurements. The large effective area of the SXT covers above 10 keV. In fact, the flight data show the spectra of the celestical objects in the hard X-ray band. In order to model the area, the reflectivity measurements in the 11.2{15.4 keV band with the energy pitch of 0.4 { 0.7 eV were made in the synchrotron beamline Spring-8 BL01B1. We obtained atomic scattering factors f1 and f2 by the curve fitting to the reflectivities of our witness sample. The edges associated with the gold's L-I, II, and III transitions are identified, of which the depths are found to be roughly 60% shallower than those expected from the Henke's atomic scattering factor.

  13. Reflectivity Around the Gold L-Edges of X-Ray Reflector of the Soft X-Ray Telescope Onboard ASTRO-H

    NASA Technical Reports Server (NTRS)

    Maeda, Yoshitomo; Kikuchi, Naomichi; Kurashima, Sho; Ishida, Manabu; Iizuka, Ryo; Hayashi, Takayuki; Okajima, Takashi; Matsumoto, Hironori; Mitsuishi, Ikuyuki; Saji, Shigetaka; hide

    2016-01-01

    We report the atomic scattering factor in the 11.215.4 keV for the ASTRO-H Soft X-ray Telescope (SXT) obtained in the ground based measurements. The large effective area of the SXT covers above 10 keV. In fact, the flight data show the spectra of the celestical objects in the hard X-ray band. In order to model the area, the reflectivity measurements in the 11.2-15.4 keV band with the energy pitch of 0.4-0.7 eV were made in the synchrotron beamline Spring-8 BL01B1. We obtained atomic scattering factors f1 and f2 by the curve fitting to the reflectivities of our witness sample. The edges associated with the golds L-I, II, and III transitions are identified, of which the depths are found to be roughly 60 percent shallower than those expected from the Henke's atomic scattering factor.

  14. Surface Morphology of Liquid and Solid Thin Films via X-Ray Reflectivity.

    NASA Astrophysics Data System (ADS)

    Shindler, Joseph Daniel

    X-ray reflectivity can be used to measure the spatial variations in the electron density on length scales from Angstroms to microns. It is sensitive to atomic scale roughness, interdiffusion in buried layers, the thickness of multilayer stacks, and in-plane correlations in each of these cases. We have pioneered the use of a high intensity, moderate resolution configuration for x-ray reflectivity which utilizes a bent crystal graphite monochromator. With this technique we can obtain a beam intensity one hundred times greater than is possible using the high resolution rotating anode configuration, while we have shown that the resulting instrumental resolution is appropriate for the vast majority of thin film work. For all of the systems studied, we were able to measure the weak diffuse scattering signal to probe the in-plane length scales of interfacial roughness, a measurement which had previously only been attempted at synchrotron sources. Studied systems include thin films and surfaces with a wide range of structural order and surface morphologies. Interest in liquid films has been of a fundamental nature. Theories on the expected film evolution with changing thickness and temperature are currently being tested with scattering experiments. We have pursued the issues of film/substrate wetting and conformality, focussing on the temperature dependence of these phenomena near the triple point. Despite the heterogeneity of the substrate potential, we see a very sharp wetting transition at or near the triple point, although below the triple point the film is still smooth, consistent with a uniform layer. We also see a loss of conformality as the fluid films thicken; this is consistent with theory and with other recent experiments. The properties of a multilayer solid film depend not only on the magnitude of the roughness of each interface, but also on the conformality between interfaces and the length scales of the roughness--i.e., whether the roughness is on the atomic

  15. Reflectivity around the gold M-edges of x-ray reflector of the Soft X-ray Telescope onboard ASTRO-H

    NASA Astrophysics Data System (ADS)

    Kurashima, Sho; Furuzawa, Akihiro; Sato, Toshiki; Kikuchi, Naomichi; Nakaniwa, Nozomi; Maeda, Yoshitomo; Ishida, Manabu; Iizuka, Ryo; Okajima, Takashi; Mori, Hideyuki; Matsumoto, Hironori; Tamura, Keisuke; Ishibashi, Kazunori; Hayashi, Takayuki; Miyazawa, Takuya; Maejima, Masato; Yoshikawa, Shun

    2016-07-01

    The X-ray astronomy satellite ASTRO-H are equipped with two equivalent soft X-ray telescopes (SXT-I and SXT-S) which cover the energy band 0.3{12 keV. The X-ray reflectors of the SXTs are coated with a gold monolayer by means of the replication technique (Okajima et al. in this volume). A series of gold M absorption edges in the 2-4 keV band causes complex structures in the energy response of the SXTs. In the same band, there are astrophysically important emission lines from Si, Ar and S. Since the SXS has unprecedentedly high spectral resolution, we have measured the reflectivity around the gold M-edges in an extremely fine energy pitch at the synchrotron radiation facility KEK PF BL11-B, with the 2 eV pitch in 2100 eV to 4100 eV band that covers the entire series of the absorption edges (M-I through M-V) at grazing incident angles to the reflectors of 0.5, 0.8, 1.0, 1.2, 1.4 degree, and with a finer pitch of 0.25 eV in the 2200 eV to 2350 eV band where the two deepest M-IV and M-V edges are included. In the resultant reflectivity curves, we have clearly identified the fine structures associated with all the M-edges. Using these data, we calculated atomic scattering factor f1 as a function of X-ray energy, with which we have built the mirror response function which can be applied to the Suzaku spectra. As a result, we have found that discrepancy of the spectral model to the Suzaku data of 4U1630-472 (a black hole transient) and the Crab nebula around the M-edges are significantly reduced from those with the official Suzaku response.

  16. Chromatic X-ray magnifying method and apparatus by Bragg reflective planes on the surface of Abbe sphere

    DOEpatents

    Thoe, Robert S.

    1991-01-01

    Method and apparatus for producing sharp, chromatic, magnified images of X-ray emitting objects, are provided. The apparatus, which constitutes an X-ray microscope or telescope, comprises a connected collection of Bragg reflecting planes, comprised of either a bent crystal or a synthetic multilayer structure, disposed on and adjacent to a locus determined by a spherical surface. The individual Bragg planes are spatially oriented to Bragg reflect radiation from the object location toward the image location. This is accomplished by making the Bragg planes spatially coincident with the surfaces of either a nested series of prolate ellipsoids of revolution, or a nested series of spheres. The spacing between the Bragg reflecting planes can be tailored to control the wavelengths and the amount of the X-radiation that is Bragg reflected to form the X-ray image.

  17. Nanofocusing of X-ray free-electron lasers by grazing-incidence reflective optics

    PubMed Central

    Yamauchi, Kazuto; Yabashi, Makina; Ohashi, Haruhiko; Koyama, Takahisa; Ishikawa, Tetsuya

    2015-01-01

    Total-reflection mirror devices for X-ray free-electron laser focusing are discussed in terms of optical design, mirror-fabrication technology, a wavefront diagnosis method and radiation-damage testing, as a review of the present status of the focusing optics at the SPring-8 angstrom compact free-electron laser (SACLA). Designed beam sizes of 1 µm and 50 nm, and spot sizes almost matching prediction have been achieved and used to explore topics at the forefront of natural science. The feasibility of these devices is determined to be sufficient for long-term and stable operation at SACLA by investigating the radiation-damage threshold and achievable accuracies in the mirror figure and alignment. PMID:25931073

  18. Observation on Surface Change of Fragile Glass: Temperature - Time Dependence Studied by X-Ray Reflectivity

    SciTech Connect

    Kikkawa, Hiroyuki; Kitahara, Amane; Takahashi, Isao

    2004-04-30

    The structural change of a fragile glass surface close to the glass transition temperature Tg is studied by using X-ray reflectivity. Measurements were performed on surfaces of maltitol, which is a typical polyalcohol fragile glass with Tg = 320K. Upon both heating and cooling, we find the following features which are also noticed in silicate glass surfaces: (i) On heating, the surface morphology indicates a variation at temperatures below Tg; (ii) A drastic increase in surface roughness occurs at a temperature about 333K on heating, which is 13K higher than Tg; (iii) During the cooling of the sample, formation of a low-density surface layer (3nm at 293K) is observed. Prior to the crystallization, nm - {mu}m sized domains were grown at the surface, which might not be reported for other glasses.

  19. Nanofocusing of X-ray free-electron lasers by grazing-incidence reflective optics.

    PubMed

    Yamauchi, Kazuto; Yabashi, Makina; Ohashi, Haruhiko; Koyama, Takahisa; Ishikawa, Tetsuya

    2015-05-01

    Total-reflection mirror devices for X-ray free-electron laser focusing are discussed in terms of optical design, mirror-fabrication technology, a wavefront diagnosis method and radiation-damage testing, as a review of the present status of the focusing optics at the SPring-8 angstrom compact free-electron laser (SACLA). Designed beam sizes of 1 µm and 50 nm, and spot sizes almost matching prediction have been achieved and used to explore topics at the forefront of natural science. The feasibility of these devices is determined to be sufficient for long-term and stable operation at SACLA by investigating the radiation-damage threshold and achievable accuracies in the mirror figure and alignment.

  20. Investigation of structure of PEDOT: PSS thin films using X-ray reflectivity

    NASA Astrophysics Data System (ADS)

    Kumar, Manoj; Rathi, Sonika; Kumar, Sunil; Vyas, Vimal; Singh, Amarjeet

    2017-05-01

    Thin Films of PEDOT: PSS on the Indium Tin Oxide substrate were prepared at different spinning speed, for instance, 1000 rpm, 1500 rpm, 2000 rpm & 4000 rpm by spin-coating technique. The out-of-plane structure of the thin films was determined by x-ray reflectivity technique to produce electron density profiles, thickness and roughness. High spinning speed (2000 and above) causes segregation of PSS at the top. The overall reduction in electron density of the films indicates that the high electron density component of the film is removed from top along the fluid due to strong centrifugal force at the top. The results bring interesting insight into the structure of PEDOT: PSS films which is likely to influence its current transport properties.

  1. Surface layering in ionic liquids: an X-ray reflectivity study.

    PubMed

    Sloutskin, Eli; Solutskin, Eli; Ocko, Benjamin M; Tamam, Lilach; Taman, Lilach; Kuzmenko, Ivan; Gog, Thomas; Deutsch, Moshe

    2005-06-01

    The surface structure and thermodynamics of two ionic liquids, based on the 1-alkyl-3-methylimidazolium cations, were studied by X-ray reflectivity and surface tensiometry. A molecular layer of a density approximately 18% higher than that of the bulk is found to form at the free surface of these liquids. In common with surface layering in liquid metals and surface freezing in melts of organic chain molecules, this effect is induced by the lower dimensionality of the surface. The concentrations of the oppositely charged ions within the surface layer are determined by chemical substitution of the anion. The temperature-dependent surface tension measurements reveal a normal, negative-slope temperature dependence. The different possible molecular arrangements within the enhanced-density surface layer are discussed.

  2. In Situ Study of Silicon Electrode Lithiation with X-ray Reflectivity

    DOE PAGES

    Cao, Chuntian; Steinrück, Hans-Georg; Shyam, Badri; ...

    2016-10-26

    Surface sensitive X-ray reflectivity (XRR) measurements were performed to investigate the electrochemical lithiation of a native oxide terminated single crystalline silicon (100) electrode in real time during the first galvanostatic discharge cycle. This allows us to gain nanoscale, mechanistic insight into the lithiation of Si and the formation of the solid electrolyte interphase (SEI). We describe an electrochemistry cell specifically designed for in situ XRR studies and have determined the evolution of the electron density profile of the lithiated Si layer (LixSi) and the SEI layer with subnanometer resolution. We propose a three-stage lithiation mechanism with a reaction limited, layer-by-layermore » lithiation of the Si at the LixSi/Si interface.« less

  3. In Situ Study of Silicon Electrode Lithiation with X-ray Reflectivity

    SciTech Connect

    Cao, Chuntian; Steinrück, Hans-Georg; Shyam, Badri; Stone, Kevin H.; Toney, Michael F.

    2016-10-26

    Surface sensitive X-ray reflectivity (XRR) measurements were performed to investigate the electrochemical lithiation of a native oxide terminated single crystalline silicon (100) electrode in real time during the first galvanostatic discharge cycle. This allows us to gain nanoscale, mechanistic insight into the lithiation of Si and the formation of the solid electrolyte interphase (SEI). We describe an electrochemistry cell specifically designed for in situ XRR studies and have determined the evolution of the electron density profile of the lithiated Si layer (LixSi) and the SEI layer with subnanometer resolution. We propose a three-stage lithiation mechanism with a reaction limited, layer-by-layer lithiation of the Si at the LixSi/Si interface.

  4. Orthoclase surface structure dissolution measured in situ by x-ray reflectivity and atomic force microscopy.

    SciTech Connect

    Sturchio, N. C.; Fenter, P.; Cheng, L.; Teng, H.

    2000-11-28

    Orthoclase (001) surface topography and interface structure were measured during dissolution by using in situ atomic force microscopy (AFM) and synchrotrons X-ray reflectivity at pH 1.1-12.9 and T = 25-84 C. Terrace roughening at low pH and step motion at high pH were the main phenomena observed, and dissolution rates were measured precisely. Contrasting dissolution mechanisms are inferred for low- and high-pH conditions. These observations clarify differences in alkali feldspar dissolution mechanisms as a function of pH, demonstrate a new in situ method for measuring face-specific dissolution rates on single crystals, and improve the fundamental basis for understanding alkali feldspar weathering processes.

  5. A triple axis double crystal multiple reflection camera for ultra small angle X-ray scattering

    NASA Astrophysics Data System (ADS)

    Lambard, Jacques; Lesieur, Pierre; Zemb, Thomas

    1992-06-01

    To extend the domain of small angle X-ray scattering requires multiple reflection crystals to collimate the beam. A double crystal, triple axis X-ray camera using multiple reflection channel cut crystals is described. Procedures for measuring the desmeared scattering cross-section on absolute scale are described as well as the measurement from several typical samples : fibrils of collagen, 0.3 μm diameter silica spheres, 0.16 μm diameter interacting latex spheres, porous lignite coal, liquid crystals in a surfactant-water system, colloidal crystal of 0.32 μm diameter silica spheres. L'extension du domaine de diffusion des rayons-X vers les petits angles demande l'emploi de cristaux à réflexions multiples pour collimater le faisceau. Nous décrivons une caméra à rayons-X à trois axes où les réflexions multiples sont réalisées dans deux cristaux à gorge. Nous donnons ensuite les procédures de déconvolution pour obtenir la section efficace de diffusion en échelle absolue, ainsi que les résultats des mesures effectuées avec plusieurs échantillons typiques : fibres de collagène, sphères de silice de 0,3 μm de diamètre, sphères de latex de 0,16 μm de diamètre en interaction, charbon lignite poreux, cristaux liquides formés dans un système eau-tensioactif, solution colloïdale de sphères de silice de 0,32 μm de diamètre.

  6. Iron speciation in human cancer cells by K-edge total reflection X-ray fluorescence-X-ray absorption near edge structure analysis

    NASA Astrophysics Data System (ADS)

    Polgári, Zs.; Meirer, F.; Sasamori, S.; Ingerle, D.; Pepponi, G.; Streli, C.; Rickers, K.; Réti, A.; Budai, B.; Szoboszlai, N.; Záray, G.

    2011-03-01

    X-ray absorption near edge structure (XANES) analysis in combination with synchrotron radiation induced total reflection X-ray fluorescence (SR-TXRF) acquisition was used to determine the oxidation state of Fe in human cancer cells and simultaneously their elemental composition by applying a simple sample preparation procedure consisting of pipetting the cell suspension onto the quartz reflectors. XANES spectra of several inorganic and organic iron compounds were recorded and compared to that of different cell lines. The XANES spectra of cells, independently from the phase of cell growth and cell type were very similar to that of ferritin, the main Fe store within the cell. The spectra obtained after CoCl 2 or NiCl 2 treatment, which could mimic a hypoxic state of cells, did not differ noticeably from that of the ferritin standard. After 5-fluorouracil administration, which could also induce an oxidative-stress in cells, the absorption edge position was shifted toward higher energies representing a higher oxidation state of Fe. Intense treatment with antimycin A, which inhibits electron transfer in the respiratory chain, resulted in minor changes in the spectrum, resembling rather the N-donor Fe-α,α'-dipyridyl complex at the oxidation energy of Fe(III), than ferritin. The incorporation of Co and Ni in the cells was followed by SR-TXRF measurements.

  7. Examining molecular clouds in the Galactic Centre region using X-ray reflection spectra simulations

    NASA Astrophysics Data System (ADS)

    Walls, M.; Chernyakova, M.; Terrier, R.; Goldwurm, A.

    2016-12-01

    In the centre of our Galaxy lies a supermassive black hole, identified with the radio source Sagittarius A⋆. This black hole has an estimated mass of around 4 million solar masses. Although Sagittarius A⋆ is quite dim in terms of total radiated energy, having a luminosity that is a factor of 1010 lower than its Eddington luminosity, there is now compelling evidence that this source was far brighter in the past. Evidence derived from the detection of reflected X-ray emission from the giant molecular clouds in the Galactic Centre region. However, the interpretation of the reflected emission spectra cannot be done correctly without detailed modelling of the reflection process. Attempts to do so can lead to an incorrect interpretation of the data. In this paper, we present the results of a Monte Carlo simulation code we developed in order to fully model the complex processes involved in the emerging reflection spectra. The simulated spectra can be compared to real data in order to derive model parameters and constrain the past activity of the black hole. In particular, we apply our code to observations of Sagittarius B2, in order to constrain the position and density of the cloud and the incident luminosity of the central source. The results of the code have been adapted to be used in XSPEC by a large community of astronomers.

  8. Stronger Reflection from Black Hole Accretion Disks in Soft X-Ray States

    NASA Astrophysics Data System (ADS)

    Steiner, James F.; Remillard, Ronald A.; García, Javier A.; McClintock, Jeffrey E.

    2016-10-01

    We analyze 15,000 spectra of 29 stellar-mass black hole (BH) candidates collected over the 16 year mission lifetime of Rossi X-ray Timing Explorer using a simple phenomenological model. As these BHs vary widely in luminosity and progress through a sequence of spectral states, which we broadly refer to as hard and soft, we focus on two spectral components: the Compton power law and the reflection spectrum it generates by illuminating the accretion disk. Our proxy for the strength of reflection is the equivalent width of the Fe-K line as measured with respect to the power law. A key distinction of our work is that for all states we estimate the continuum under the line by excluding the thermal disk component and using only the component that is responsible for fluorescing the Fe-K line, namely, the Compton power law. We find that reflection is several times more pronounced (˜3) in soft compared to hard spectral states. This is most readily caused by the dilution of the Fe line amplitude from Compton scattering in the corona, which has a higher optical depth in hard states. Alternatively, this could be explained by a more compact corona in soft (compared to hard) states, which would result in a higher reflection fraction.

  9. NuSTAR SPECTROSCOPY OF MULTI-COMPONENT X-RAY REFLECTION FROM NGC 1068

    SciTech Connect

    Bauer, Franz E.; Arévalo, Patricia; Walton, Dominic J.; Baloković, Mislav; Brightman, Murray; Harrison, Fiona A.; Koss, Michael J.; Puccetti, Simonetta; Gandhi, Poshak; Stern, Daniel; Alexander, David M.; Moro, Agnese Del; Boggs, Steve E.; Craig, William W.; Brandt, William N.; Luo, Bin; Christensen, Finn E.; Comastri, Andrea; Hailey, Charles J.; Hickox, Ryan; and others

    2015-10-20

    We report on high-energy X-ray observations of the Compton-thick Seyfert 2 galaxy NGC 1068 with NuSTAR, which provide the best constraints to date on its >10 keV spectral shape. The NuSTAR data are consistent with those from past and current instruments to within cross-calibration uncertainties, and we find no strong continuum or line variability over the past two decades, which is in line with its X-ray classification as a reflection-dominated Compton-thick active galactic nucleus. The combined NuSTAR, Chandra, XMM-Newton, and Swift BAT spectral data set offers new insights into the complex secondary emission seen instead of the completely obscured transmitted nuclear continuum. The critical combination of the high signal-to-noise NuSTAR data and the decomposition of the nuclear and extranuclear emission with Chandra allow us to break several model degeneracies and greatly aid physical interpretation. When modeled as a monolithic (i.e., a single N{sub H}) reflector, none of the common Compton reflection models are able to match the neutral fluorescence lines and broad spectral shape of the Compton reflection hump without requiring unrealistic physical parameters (e.g., large Fe overabundances, inconsistent viewing angles, or poor fits to the spatially resolved spectra). A multi-component reflector with three distinct column densities (e.g., with best-fit values of N{sub H} of 1.4 × 10{sup 23}, 5.0 × 10{sup 24}, and 10{sup 25} cm{sup −2}) provides a more reasonable fit to the spectral lines and Compton hump, with near-solar Fe abundances. In this model, the higher N{sub H} component provides the bulk of the flux to the Compton hump, while the lower N{sub H} component produces much of the line emission, effectively decoupling two key features of Compton reflection. We find that ≈30% of the neutral Fe Kα line flux arises from >2″ (≈140 pc) and is clearly extended, implying that a significant fraction (and perhaps most) of the <10 keV reflected component

  10. NuSTAR Spectroscopy of Multi-component X-Ray Reflection from NGC 1068

    NASA Astrophysics Data System (ADS)

    Bauer, Franz E.; Arévalo, Patricia; Walton, Dominic J.; Koss, Michael J.; Puccetti, Simonetta; Gandhi, Poshak; Stern, Daniel; Alexander, David M.; Baloković, Mislav; Boggs, Steve E.; Brandt, William N.; Brightman, Murray; Christensen, Finn E.; Comastri, Andrea; Craig, William W.; Del Moro, Agnese; Hailey, Charles J.; Harrison, Fiona A.; Hickox, Ryan; Luo, Bin; Markwardt, Craig B.; Marinucci, Andrea; Matt, Giorgio; Rigby, Jane R.; Rivers, Elizabeth; Saez, Cristian; Treister, Ezequiel; Urry, C. Megan; Zhang, William W.

    2015-10-01

    We report on high-energy X-ray observations of the Compton-thick Seyfert 2 galaxy NGC 1068 with NuSTAR, which provide the best constraints to date on its >10 keV spectral shape. The NuSTAR data are consistent with those from past and current instruments to within cross-calibration uncertainties, and we find no strong continuum or line variability over the past two decades, which is in line with its X-ray classification as a reflection-dominated Compton-thick active galactic nucleus. The combined NuSTAR, Chandra, XMM-Newton, and Swift BAT spectral data set offers new insights into the complex secondary emission seen instead of the completely obscured transmitted nuclear continuum. The critical combination of the high signal-to-noise NuSTAR data and the decomposition of the nuclear and extranuclear emission with Chandra allow us to break several model degeneracies and greatly aid physical interpretation. When modeled as a monolithic (i.e., a single NH) reflector, none of the common Compton reflection models are able to match the neutral fluorescence lines and broad spectral shape of the Compton reflection hump without requiring unrealistic physical parameters (e.g., large Fe overabundances, inconsistent viewing angles, or poor fits to the spatially resolved spectra). A multi-component reflector with three distinct column densities (e.g., with best-fit values of NH of 1.4 × 1023, 5.0 × 1024, and 1025 cm-2) provides a more reasonable fit to the spectral lines and Compton hump, with near-solar Fe abundances. In this model, the higher NH component provides the bulk of the flux to the Compton hump, while the lower NH component produces much of the line emission, effectively decoupling two key features of Compton reflection. We find that ≈30% of the neutral Fe Kα line flux arises from >2″ (≈140 pc) and is clearly extended, implying that a significant fraction (and perhaps most) of the <10 keV reflected component arises from regions well outside a parsec

  11. Improved reflection models of black hole accretion disks: Treating the angular distribution of X-rays

    SciTech Connect

    García, J.; Steiner, J. F.; McClintock, J. E.; Brenneman, L. E-mail: jsteiner@head.cfa.harvard.edu E-mail: lbrenneman@cfa.harvard.edu; and others

    2014-02-20

    X-ray reflection models are used to constrain the properties of the accretion disk, such as the degree of ionization of the gas and the elemental abundances. In combination with general relativistic ray tracing codes, additional parameters like the spin of the black hole and the inclination to the system can be determined. However, current reflection models used for such studies only provide angle-averaged solutions for the flux reflected at the surface of the disk. Moreover, the emission angle of the photons changes over the disk due to relativistic light bending. To overcome this simplification, we have constructed an angle-dependent reflection model with the XILLVER code and self-consistently connected it with the relativistic blurring code RELLINE. The new model, relxill, calculates the proper emission angle of the radiation at each point on the accretion disk and then takes the corresponding reflection spectrum into account. We show that the reflected spectra from illuminated disks follow a limb-brightening law highly dependent on the ionization of disk and yet different from the commonly assumed form I∝ln (1 + 1/μ). A detailed comparison with the angle-averaged model is carried out in order to determine the bias in the parameters obtained by fitting a typical relativistic reflection spectrum. These simulations reveal that although the spin and inclination are mildly affected, the Fe abundance can be overestimated by up to a factor of two when derived from angle-averaged models. The fit of the new model to the Suzaku observation of the Seyfert galaxy Ark 120 clearly shows a significant improvement in the constraint of the physical parameters, in particular by enhancing the accuracy in the inclination angle and the spin determinations.

  12. Bromine and bromide content in soils: Analytical approach from total reflection X-ray fluorescence spectrometry.

    PubMed

    Gallardo, Helena; Queralt, Ignasi; Tapias, Josefina; Candela, Lucila; Margui, Eva

    2016-08-01

    Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (<63 μm) gave a 3.7 mg kg(-1) limit of detection for bromine which, in most cases, was suitable for monitoring total bromine content in soils (Br content range in soils = 5-40 mg kg(-1)). Information about bromide determination in soils is also possible by analyzing the Br content in water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 μL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 μg L(-1). Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water.

  13. Integrated X-Ray Reflectivity Measurements for Elliptically Curved PET Crystals

    SciTech Connect

    Haugh, M J; Ross, P W; Regan, P W; Magoon, J; Shoup, M J; Barrios, M A; Emig, J A; Fournier, K B

    2012-04-26

    Spectroscopy provides valuable information about the temperature and density of a compressed pellet in a plasma. Elliptically curved pentaerythritol (PET) crystals are used as components for spectrometers. Their elliptical geometry gives several advantages related to spectral energy range, source focus, and spectral image compression.[1] The crystal curvature increases the spectrometer throughput but at the cost of a loss in resolution. Four different crystals are used in a spectrometer at the National Ignition Facility (NIF) target chamber at Lawrence Livermore National Laboratory (LLNL). Figure 1 shows the arrangement of the elliptical PET crystals in the snout of a NIF target diagnostic shown in Figure 2. The spectrum from the crystals is captured by four image plates located behind the crystals. A typical mandrel, the darkened section, upon which the PET crystal is glued, is shown in Figure 3, which also shows the complete ellipse. There are four elliptical segment types, each having the same major axis but a different minor axis. The crystals are 150 mm long in the diffraction direction and 25.4 mm high. Two crystals of each type were calibrated. The throughput for each spectrometer is determined by the integrated reflectivity of the PET crystal.[1] The goal of this effort was to measure the reflectivity curve of the PET curved crystal at several energies and determine the integrated reflectivity and the curve width as a function of the X-ray spectral energy and location on the ellipse where the beam strikes.

  14. Multi-modal hard x-ray imaging with a laboratory source using selective reflection from a mirror.

    PubMed

    Pelliccia, Daniele; Paganin, David M

    2014-04-01

    Multi-modal hard x-ray imaging sensitive to absorption, refraction, phase and scattering contrast is demonstrated using a simple setup implemented with a laboratory source. The method is based on selective reflection at the edge of a mirror, aligned to partially reflect a pencil x-ray beam after its interaction with a sample. Quantitative scattering contrast from a test sample is experimentally demonstrated using this method. Multi-modal imaging of a house fly (Musca domestica) is shown as proof of principle of the technique for biological samples.

  15. Development of a total reflection double-slit for evaluation of spatial coherence in hard X-ray region

    NASA Astrophysics Data System (ADS)

    Tsuji, T.; Koyama, T.; Takano, H.; Tsusaka, Y.; Kagoshima, Y.

    2009-09-01

    A new total reflection double-slit for hard X-ray region was developed. It consists of Au narrow stripes deposited on a SiO2 substrate and can function equivalently as a conventional Young's interferometer by operating with a small grazing incident angle. The Young's interferometer using the total reflection double-slit was constructed at Hyogo-ID BL of SPring-8, and the spatial coherence at 10 keV X-rays was evaluated by analyzing the interference fringes.

  16. Multi-modal hard x-ray imaging with a laboratory source using selective reflection from a mirror

    PubMed Central

    Pelliccia, Daniele; Paganin, David M.

    2014-01-01

    Multi-modal hard x-ray imaging sensitive to absorption, refraction, phase and scattering contrast is demonstrated using a simple setup implemented with a laboratory source. The method is based on selective reflection at the edge of a mirror, aligned to partially reflect a pencil x-ray beam after its interaction with a sample. Quantitative scattering contrast from a test sample is experimentally demonstrated using this method. Multi-modal imaging of a house fly (Musca domestica) is shown as proof of principle of the technique for biological samples. PMID:24761297

  17. Alignment of off-plane X-ray reflection gratings using optical light

    NASA Astrophysics Data System (ADS)

    Tutt, James; McEntaffer, Randall; Donovan, Benjamin; Schultz, Ted; DeRoo, Casey; Hertz, Edward; Allured, Ryan

    2017-08-01

    The next generation of high resolution soft X-ray spectrometers require large effective areas and high resolving capability. This can be achieved through the use of off-plane reflection gratings. X-rays will only reflect if they are incident onto a surface at a shallow graze angle; therefore, arrays of off-plane gratings are placed into the converging beam of a telescope to achieve the necessary effective area. To maintain the high resolving power of a single grating across this array, the gratings have to be very precisely aligned to one another and fanned so that they match the convergence of the telescope.Leveraging previous work that co-aligned 4 state of the art gratings into a module, 26 gratings will be co-aligned into a module that will be launched on the sub-orbital rocket WRX-R. The alignment procedure is unchanged, but improvements have been made to stabilize the setup. The alignment procedure was found to be highly temperature dependent and the opto-mechanics suffered from mechanical instabilities. To solve these issues, the new setup uses a high precision temperature control unit and a larger optical bench allowing the setup to be simplified.The alignment method is based around the generation of a light wavefront which reflects off the grating surface. This wavefront is measured using a Shack-Hartmann sensor, which allows the gratings orientation relative to the sensor normal to be found. A hexapod is then used to move the grating, allowing the grating surface to be aligned in pitch, roll and yaw. The x, y and z positions for each grating are constrained through the mechanical tolerance of the alignment mount and high precision stages. The aligned gratings are mounted into an Invar module and a theodolite is used to measure the relative position of the module to the known position of the grating.This poster discusses the improvements made to the grating alignment process and the proposed path towards producing the array of 26 co-aligned gratings that

  18. Integrated X-ray testing of the electro-optical breadboard model for the XMM reflection grating spectrometer

    SciTech Connect

    Bixler, J.V.; Craig, W.; Decker, T.; Aarts, H.; Boggende, T. den; Brinkman, A.C.; Burkert, W.; Brauninger, H.; Branduardi-Raymont, G.; Dubbeldam, L.

    1994-07-12

    X-ray calibration of the Electro-Optical Breadboard Model (EOBB) of the XXM Reflection Grating Spectrometer has been carried out at the Panter test facility in Germany. The EOBB prototype optics consisted of a four-shell grazing incidence mirror module followed by an array of eight reflection gratings. The dispersed x-rays were detected by an array of three CCDs. Line profile and efficiency measurements where made at several energies, orders, and geometric configurations for individual gratings and for the grating array as a whole. The x-ray measurements verified that the grating mounting method would meet the stringent tolerances necessary for the flight instrument. Post EOBB metrology of the individual gratings and their mountings confirmed the precision of the grating boxes fabrication. Examination of the individual grating surface`s at micron resolution revealed the cause of anomalously wide line profiles to be scattering due to the crazing of the replica`s surface.

  19. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

    SciTech Connect

    Burcklen, C.; Soufli, R.; Gullikson, E.; Meltchakov, E.; Dennetiere, D.; Polack, F.; Capitanio, B.; Thomasset, M.; Jerome, A.; de Rossi, S.; Delmotte, F.

    2016-03-24

    Here, we present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1–1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (optical constants) values for Cr.

  20. Testing the Kerr Black Hole Hypothesis Using X-Ray Reflection Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Cárdenas-Avendaño, Alejandro; Dauser, Thomas; García, Javier A.; Nampalliwar, Sourabh

    2017-06-01

    We present the first X-ray reflection model for testing the assumption that the metric of astrophysical black holes is described by the Kerr solution. We employ the formalism of the transfer function proposed by Cunningham. The calculations of the reflection spectrum of a thin accretion disk are split into two parts: the calculation of the transfer function and the calculation of the local spectrum at any emission point in the disk. The transfer function only depends on the background metric and takes into account all the relativistic effects (gravitational redshift, Doppler boosting, and light bending). Our code computes the transfer function for a spacetime described by the Johannsen metric and can easily be extended to any stationary, axisymmetric, and asymptotically flat spacetime. Transfer functions and single line shapes in the Kerr metric are compared to those calculated from existing codes to check that we reach the necessary accuracy. We also simulate some observations with NuSTAR and LAD/eXTP and fit the data with our new model to show the potential capabilities of current and future observations to constrain possible deviations from the Kerr metric.

  1. [Development of X-ray Reflection Grating Technology for the Constellation-X Mission

    NASA Technical Reports Server (NTRS)

    Schattenburg, Mark L.

    2005-01-01

    This Grant supports MIT technology development of x-ray reflection gratings for the Constellation-X Reflection Grating Spectrometer (RGS). Since the start of the Grant MIT has extended its previously-developed patterning and super-smooth, blazed grating fabrication technology to ten-times smaller grating periods and ten-times larger blaze angles to demonstrate feasibility and performance in the off-plane grating geometry. In the past year we have focused our efforts on extending our Nanoruler grating fabrication tool to enable it to perform variable-period scanning-beam interference lithography (VP-SBIL). This new capability required extensive optical and mechanical improvements to the system. The design phase of this work is largely completed and key components are now on order and assembly has begun. Over the next several months the new VP-SBIL Nanoruler system will be completed and testing begun. We have also demonstrated a new technique for patterning gratings using the Nanoruler called Doppler mode, which will be important for patterning the radial groove gratings for the RGS using the new VP-SBIL system. Flat and thin grating substrates will be critical for the RGS. In the last year we demonstrated a new technique for flattening thin substrates using magneto-rheologic fluid polishing (MRF) and achieved 2 arcsecond flatness with a 0.5 mm-thick substrate-a world's record. This meets the Con X requirement for grating substrate flatness.

  2. [Development of X-ray Reflection Grating Technology for the Constellation-X Mission

    NASA Technical Reports Server (NTRS)

    Schattenburg, Mark L.

    2005-01-01

    This Grant supports MIT technology development of x-ray reflection gratings for the Constellation-X Reflection Grating Spectrometer (RGS). Since the start of the Grant MIT has extended its previously-developed patterning and super-smooth, blazed grating fabrication technology to ten-times smaller grating periods and ten-times larger blaze angles to demonstrate feasibility and performance in the off-plane grating geometry. In the past year we have focused our efforts on extending our Nanoruler grating fabrication tool to enable it to perform variable-period scanning-beam interference lithography (VP-SBIL). This new capability required extensive optical and mechanical improvements to the system. The design phase of this work is largely completed and key components are now on order and assembly has begun. Over the next several months the new VP-SBIL Nanoruler system will be completed and testing begun. We have also demonstrated a new technique for patterning gratings using the Nanoruler called Doppler mode, which will be important for patterning the radial groove gratings for the RGS using the new VP-SBIL system. Flat and thin grating substrates will be critical for the RGS. In the last year we demonstrated a new technique for flattening thin substrates using magneto-rheologic fluid polishing (MRF) and achieved 2 arcsecond flatness with a 0.5 mm-thick substrate-a world's record. This meets the Con X requirement for grating substrate flatness.

  3. Measuring graft stability in a tethered polyelectrolyte film by X-ray and neutron reflectivity

    NASA Astrophysics Data System (ADS)

    Dimitriou, Michael; Galvin, Casey; Satija, Sushil; Genzer, Jan

    2013-03-01

    The instability of tethered polymer films in mild conditions has recently brought into question the limits of use of such layers in certain technologies, such as anti-fouling coatings. In order to better understand the process of chain degrafting in a polymer brush, we have used X-ray reflectivity (XR) and neutron reflectivity (NR) to examine tethered layers of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA). Exposing an ~ 30 nm thick film of PDMAEMA brushes grafted on flat silica-coated substrates to a range of relative humidities (RH) resulted in reproducible thickness changes as measured by XR, illustrating the need of ambient solvent to induce degrafting. The thickness change showed non-linear behavior, increasing rapidly above ~ 70% RH and swelling to ~ 230% of its original thickness at ~ 99% RH. In order to better understand the apparent diffusive process of vapor into the brush, we have exposed brushes to isotopically labeled vapors. Using XR and NR, we examined the extent of modification in scattering length density within the brush using box and gradient models, and discuss the apparent entropic and enthalpic forces at play. We also conducted in situ aqueous measurements of similar samples to comprehend the degrafting process of a polymer brush. Through an appropriate choice of model, we detect variations in grafting density as a function of incubation time.

  4. A soft X-ray beam-splitting multilayer optic for the NASA GEMS Bragg Reflection Polarimeter

    DOE PAGES

    Allured, Ryan; Kaaret, Philip; Fernandez-Perea, Monica; ...

    2013-04-12

    A soft X-ray, beam-splitting, multilayer optic has been developed for the Bragg Reflection Polarimeter (BRP) on the NASA Gravity and Extreme Magnetism Small Explorer Mission (GEMS). The optic is designed to reflect 0.5 keV X-rays through a 90° angle to the BRP detector, and transmit 2–10 keV X-rays to the primary polarimeter. The transmission requirement prevents the use of a thick substrate, so a 2 μm thick polyimide membrane was used. Atomic force microscopy has shown the membrane to possess high spatial frequency roughness less than 0.2 nm rms, permitting adequate X-ray reflectance. A multilayer thin film was especially developedmore » and deposited via magnetron sputtering with reflectance and transmission properties that satisfy the BRP requirements and with near-zero stress. Furthermore, reflectance and transmission measurements of BRP prototype elements closely match theoretical predictions, both before and after rigorous environmental testing.« less

  5. A soft X-ray beam-splitting multilayer optic for the NASA GEMS Bragg Reflection Polarimeter

    SciTech Connect

    Allured, Ryan; Kaaret, Philip; Fernandez-Perea, Monica; Soufli, Regina; Alameda, Jennifer B.; Pivovaroff, Michael J.; Gullikson, Eric M.

    2013-04-12

    A soft X-ray, beam-splitting, multilayer optic has been developed for the Bragg Reflection Polarimeter (BRP) on the NASA Gravity and Extreme Magnetism Small Explorer Mission (GEMS). The optic is designed to reflect 0.5 keV X-rays through a 90° angle to the BRP detector, and transmit 2–10 keV X-rays to the primary polarimeter. The transmission requirement prevents the use of a thick substrate, so a 2 μm thick polyimide membrane was used. Atomic force microscopy has shown the membrane to possess high spatial frequency roughness less than 0.2 nm rms, permitting adequate X-ray reflectance. A multilayer thin film was especially developed and deposited via magnetron sputtering with reflectance and transmission properties that satisfy the BRP requirements and with near-zero stress. Furthermore, reflectance and transmission measurements of BRP prototype elements closely match theoretical predictions, both before and after rigorous environmental testing.

  6. X-RAY REFLECTED SPECTRA FROM ACCRETION DISK MODELS. III. A COMPLETE GRID OF IONIZED REFLECTION CALCULATIONS

    SciTech Connect

    Garcia, J.; McClintock, J. E.; Dauser, T.; Wilms, J.; Eikmann, W.; Reynolds, C. S.; Kallman, T. R. E-mail: jem@cfa.harvard.edu E-mail: thomas.dauser@sternwarte.uni-erlangen.de E-mail: wiebke.eikmann@sternwarte.uni-erlangen.de

    2013-05-10

    We present a new and complete library of synthetic spectra for modeling the component of emission that is reflected from an illuminated accretion disk. The spectra were computed using an updated version of our code XILLVER that incorporates new routines and a richer atomic database. We offer in the form of a table model an extensive grid of reflection models that cover a wide range of parameters. Each individual model is characterized by the photon index {Gamma} of the illuminating radiation, the ionization parameter {xi} at the surface of the disk (i.e., the ratio of the X-ray flux to the gas density), and the iron abundance A{sub Fe} relative to the solar value. The ranges of the parameters covered are 1.2 {<=} {Gamma} {<=} 3.4, 1 {<=} {xi} {<=} 10{sup 4}, and 0.5 {<=} A{sub Fe} {<=} 10. These ranges capture the physical conditions typically inferred from observations of active galactic nuclei, and also stellar-mass black holes in the hard state. This library is intended for use when the thermal disk flux is faint compared to the incident power-law flux. The models are expected to provide an accurate description of the Fe K emission line, which is the crucial spectral feature used to measure black hole spin. A total of 720 reflection spectra are provided in a single FITS file (http://hea-www.cfa.harvard.edu/{approx}javier/xillver/) suitable for the analysis of X-ray observations via the atable model in XSPEC. Detailed comparisons with previous reflection models illustrate the improvements incorporated in this version of XILLVER.

  7. X-ray Reflected Spectra from Accretion Disk Models. III. A Complete Grid of Ionized Reflection Calculations

    NASA Technical Reports Server (NTRS)

    Garcia, J.; Dauser, T.; Reynolds, C. S.; Kallman, T. R.; McClintock, J. E.; Wilms, J.; Ekmann, W.

    2013-01-01

    We present a new and complete library of synthetic spectra for modeling the component of emission that is reflected from an illuminated accretion disk. The spectra were computed using an updated version of our code xillver that incorporates new routines and a richer atomic data base. We offer in the form of a table model an extensive grid of reflection models that cover a wide range of parameters. Each individual model is characterized by the photon index Gamma of the illuminating radiation, the ionization parameter zeta at the surface of the disk (i.e., the ratio of the X-ray flux to the gas density), and the iron abundance A(sub Fe) relative to the solar value. The ranges of the parameters covered are: 1.2 <= Gamma <= 3.4, 1 <= zeta <= 104, and 0.5 <= A(sub Fe) <= 10. These ranges capture the physical conditions typically inferred from observations of active galactic nuclei, and also stellar-mass black holes in the hard state. This library is intended for use when the thermal disk flux is faint compared to the incident power-law flux. The models are expected to provide an accurate description of the Fe K emission line, which is the crucial spectral feature used to measure black hole spin. A total of 720 reflection spectra are provided in a single FITS file suitable for the analysis of X-ray observations via the atable model in xspec. Detailed comparisons with previous reflection models illustrate the improvements incorporated in this version of xillver.

  8. X-ray absorption and reflection as probes of the GaN conduction bands: Theory and experiments

    SciTech Connect

    Lambrecht, W.R.L.; Rashkeev, S.N.; Segall, B.

    1997-04-01

    X-ray absorption measurements are a well-known probe of the unoccupied states in a material. The same information can be obtained by using glancing angle X-ray reflectivity. In spite of several existing band structure calculations of the group III nitrides and previous optical studies in UV range, a direct probe of their conduction band densities of states is of interest. The authors performed a joint experimental and theoretical investigation using both of these experimental techniques for wurtzite GaN.

  9. Determination of element levels in human serum: Total reflection X-ray fluorescence applications

    NASA Astrophysics Data System (ADS)

    Majewska, U.; Łyżwa, P.; Łyżwa, K.; Banaś, D.; Kubala-Kukuś, A.; Wudarczyk-Moćko, J.; Stabrawa, I.; Braziewicz, J.; Pajek, M.; Antczak, G.; Borkowska, B.; Góźdź, S.

    2016-08-01

    Deficiency or excess of elements could disrupt proper functioning of the human body and could lead to several disorders. Determination of their concentrations in different biological human fluids and tissues should become a routine practice in medical treatment. Therefore the knowledge about appropriate element concentrations in human organism is required. The purpose of this study was to determine the concentration of several elements (P, S, Cl, K, Ca, Cr, Fe, Cu, Zn, Se, Br, Rb, Pb) in human serum and to define the reference values of element concentration. Samples of serum were obtained from 105 normal presumably healthy volunteers (66 women aged between 15 and 78 years old; 39 men aged between 15 and 77 years old). Analysis has been done for the whole studied population and for subgroups by sex and age. It is probably first so a wide study of elemental composition of serum performed in the case of Świętokrzyskie region. Total reflection X-ray fluorescence (TXRF) method was used to perform the elemental analysis. Spectrometer S2 Picofox (Bruker AXS Microanalysis GmbH) was used to identify and measure elemental composition of serum samples. Finally, 1st and 3rd quartiles were accepted as minimum and maximum values of concentration reference range.

  10. Production of the ideal sample shape for Total Reflection X-ray Fluorescence analysis

    NASA Astrophysics Data System (ADS)

    Horntrich, C.; Kregsamer, P.; Prost, J.; Stadlbauer, F.; Wobrauschek, P.; Streli, C.

    2012-11-01

    Total Reflection X-ray Fluorescence analysis (TXRF) is a well-established analytical method in the semiconductor industry for the analysis of silicon wafer surfaces. For the calibration of the spectrometer typically an external standard is used which is sensitive to quantification errors. In general TXRF is known to allow for linear calibration. For small sample amounts (pg to ng region) the thin film approximation is valid neglecting absorption effects of the exciting and the detected radiation. For higher total amounts of sample the relation between fluorescence intensity and sample amount diverges from linearity (saturation effect). These deviations lead to difficulties in quantification with external standard. Content of the presented work is the production of the ideal TXRF sample shape, which was theoretically determined to be ring shaped. A possibility for the production of samples with ring shape is the use of a nanodispensing system combined with a positioning device. Therewith it is possible to produce ring shaped samples in a controlled way with the ring consisting of individual nanodroplets, so that the wanted diameter of the ring can be chosen. A comparison of the fluorescence intensities emitted by contracted and ring shaped samples shows that the ring shape is not only theoretically the best TXRF shape but also experimentally. It could be proven that for contracted samples the saturation effect occurs at a lower sample mass than for samples with ring shape.

  11. Total reflection X-ray fluorescence as a fast multielemental technique for human placenta sample analysis

    NASA Astrophysics Data System (ADS)

    Marguí, E.; Ricketts, P.; Fletcher, H.; Karydas, A. G.; Migliori, A.; Leani, J. J.; Hidalgo, M.; Queralt, I.; Voutchkov, M.

    2017-04-01

    In the present contribution, benchtop total reflection X-ray fluorescence spectrometry (TXRF) has been evaluated as a cost-effective multielemental analytical technique for human placenta analysis. An easy and rapid sample preparation consisting of suspending 50 mg of sample in 1 mL of a Triton 1% solution in deionized water showed to be the most suitable for this kind of samples. However, for comparison purposes, an acidic microwave acidic digestion procedure was also applied. For both sample treatment methodologies, limits of detection for most elements were in the low mg/kg level. Accurate and precise results were obtained using internal standardization as quantification approach and applying a correction factor to compensate for absorption effects. The correction factor was based on the proportional ratio between the slurry preparation results and those obtained for the analysis of a set of human placenta samples analysed by microwave acidic digestion and ICP-AES analysis. As a study case, the developed TXRF methodology was applied for multielemental analysis (K, Ca, Fe, Cu, Zn, As, Se, Br, Rb and Sr) of several healthy women's placenta samples from two regions in Jamaica.

  12. Rainwater analysis by synchrotron radiation-total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    López, María L.; Ceppi, Sergio A.; Asar, María L.; Bürgesser, Rodrigo E.; Ávila, Eldo E.

    2015-11-01

    Total reflection X-ray fluorescence analysis excited with synchrotron radiation was used to quantify the elemental concentration of rainwater in Córdoba, Argentina. Standard solutions with gallium as internal standard were prepared for the calibration curves. Rainwater samples of 5 μl were added to an acrylic reflector, allowed to dry, and analyzed for 200 s measuring time. The elemental concentrations of As, Ca, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, S, Sr, V, and Zn were determined. The electrical conductivity, pH, and elemental concentrations were compared to data previously reported for the soluble fraction of rainwater at different sites. A factor analysis was performed in order to determine the sources that contributed to the elemental concentration in rainwater. Anthropogenic sources were identified as traffic pollution, vehicular emissions, and metallurgical factories. The quality of rainwater was analyzed by comparing the concentrations of all the elements in rainwater samples with the WHO guideline values for drinking water. The results show the need to control the atmospheric emissions in order to preserve the quality of rainwater. SR-TXRF analysis of chemical composition of rainwater in Córdoba represents the very first contribution in the region to the knowledge of the concentration of trace metals in the soluble fraction of rainwater. These data are scarce, especially in the Southern Hemisphere.

  13. Total reflection X-ray fluorescence as a tool for food screening

    NASA Astrophysics Data System (ADS)

    Borgese, Laura; Bilo, Fabjola; Dalipi, Rogerta; Bontempi, Elza; Depero, Laura E.

    2015-11-01

    This review provides a comprehensive overview of the applications of total reflection X-ray fluorescence (TXRF) in the field of food analysis. Elemental composition of food is of great importance, since food is the main source of essential, major and trace elements for animals and humans. Some potentially toxic elements, dangerous for human health may contaminate food, entering the food chain from the environment, processing, and storage. For this reason the elemental analysis of food is fundamental for safety assessment. Fast and sensitive analytical techniques, able to detect major and trace elements, are required as a result of the increasing demand on multi-elemental information and product screening. TXRF is suitable for elemental analysis of food, since it provides simultaneous multi-elemental identification in a wide dynamic range of concentrations. Several different matrices may be analyzed obtaining results with a good precision and accuracy. In this review, the most recent literature about the use of TXRF for the analysis of food is reported. The focus is placed on the applications within food quality monitoring of drinks, beverages, vegetables, fruits, cereals, animal derivatives and dietary supplements. Furthermore, this paper provides a critical outlook on the developments required to transfer these methods from research to the industrial and analytical laboratories contexts.

  14. Forensic identification of pharmaceuticals via portable X-ray fluorescence and diffuse reflectance spectroscopy.

    PubMed

    Shutic, Sarah; Chakraborty, Somsubhra; Li, Bin; Weindorf, David C; Sperry, Kathy; Casadonte, Dominick

    2017-10-01

    The importance of unknown substance identification in forensic science is vital to implementation or exclusion of criminal charges against an offender. While traditional laboratory measures include the use of gas chromatography/mass spectroscopy, an alternate method has been proposed to efficiently perform presumptive analyses of unknown substances at a crime scene or at airport security points. The use of portable X-ray fluorescence (PXRF) and visible near infrared diffuse reflectance spectroscopy (DRS) to determine elemental composition was applied to pharmaceutical medications (n=83), which were then categorized into 21 classifications based on their active ingredients. Each pharmaceutical was processed by standard laboratory procedures and scanned with both PXRF and DRS. Lastly, the datasets obtained were compared using multivariate statistical analyses. The aforementioned devices indicate that differentiation of unknown substances is clearly demonstrated among the samples with 73.49% DRS classification accuracy. Thus, the approach shows promise for future development as a rapid analytical technique for unknown pharmaceutical substances and/or illicit narcotics. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Determination of copper nanoparticle size distributions with total reflection X-ray fluorescence spectroscopy

    SciTech Connect

    Singh, Andy; Luening, Katharina; Brennan, Sean; Homma, Takayuki; Kubo, Nobuhiro; Nowak, Stanisław H.; Pianetta, Piero

    2017-01-01

    Total reflection X-ray fluorescence (TXRF) analysis is extensively used by the semiconductor industry for measuring trace metal contamination on silicon surfaces. In addition to determining the quantity of impurities on a surface, TXRF can reveal information about the vertical distribution of contaminants by measuring the fluorescence signal as a function of the angle of incidence. In this study, two samples were intentionally contaminated with copper in non-deoxygenated and deoxygenated ultrapure water (UPW) resulting in impurity profiles that were either atomically dispersed in a thin film or particle-like, respectively. The concentration profile of the samples immersed into deoxygenated UPW was calculated using a theoretical concentration profile representative of particles, yielding a mean particle height of 16.1 nm. However, the resulting theoretical profile suggested that a distribution of particle heights exists on the surface. The fit of the angular distribution data was further refined by minimizing the residual error of a least-squares fit employing a model with a Gaussian distribution of particle heights about the mean height. The presence of a height distribution was also confirmed with atomic force microscopy measurements.

  16. Determination of copper nanoparticle size distributions with total reflection X-ray fluorescence spectroscopy.

    PubMed

    Singh, Andy; Luening, Katharina; Brennan, Sean; Homma, Takayuki; Kubo, Nobuhiro; Nowak, Stanisław H; Pianetta, Piero

    2017-01-01

    Total reflection X-ray fluorescence (TXRF) analysis is extensively used by the semiconductor industry for measuring trace metal contamination on silicon surfaces. In addition to determining the quantity of impurities on a surface, TXRF can reveal information about the vertical distribution of contaminants by measuring the fluorescence signal as a function of the angle of incidence. In this study, two samples were intentionally contaminated with copper in non-deoxygenated and deoxygenated ultrapure water (UPW) resulting in impurity profiles that were either atomically dispersed in a thin film or particle-like, respectively. The concentration profile of the samples immersed into deoxygenated UPW was calculated using a theoretical concentration profile representative of particles, yielding a mean particle height of 16.1 nm. However, the resulting theoretical profile suggested that a distribution of particle heights exists on the surface. The fit of the angular distribution data was further refined by minimizing the residual error of a least-squares fit employing a model with a Gaussian distribution of particle heights about the mean height. The presence of a height distribution was also confirmed with atomic force microscopy measurements.

  17. X-ray reflectivity studies of ferroelectric and dielectric multilayer structures

    NASA Astrophysics Data System (ADS)

    Cao, Jiang-Li; Solbach, Axel; Klemradt, Uwe

    2005-02-01

    Dielectric and ferroelectric thin-film capacitors are of great importance as dynamic random-access memories (DRAM) and non-volatile random-access memories (NVRAM) for storage technology applications. Further improvements of the electrical performance of these devices require particularly a better control of thin-film engineering, since nanoscale layers of complex stoichiometry are subjected to relatively high-thermal budgets during the integration process. X-ray specular and diffuse reflectivity can provide valuable insight into current material problems of this field, e.g. structural changes and the possibility of interfacial reactions. An example is given for the annealing of thin Pb(Zr 0.3Ti 0.7)O 3 (PZT) films on Pt/Ti-based layered electrodes. The correlation of electrical function and structural changes subsequent to electrical stress requires in situ investigations under applied electric fields. We report first experiments on Pt/PZT/Pt/Ti-films and discuss the setup of electrical in situ measurements under grazing incidence.

  18. Total reflection X-ray fluorescence analysis of pollen as an indicator for atmospheric pollution*1

    NASA Astrophysics Data System (ADS)

    Pepponi, G.; Lazzeri, P.; Coghe, N.; Bersani, M.; Gottardini, E.; Cristofolini, F.; Clauser, G.; Torboli, A.

    2004-08-01

    The viability of pollen is affected by environmental pollution and its use as a bio-indicator is proposed. Such effects can be observed and quantified by biological tests. However, a more accurate identification of the agents affecting the viability is required in order to validate the biological assay for environmental monitoring. The chemical analysis of pollen is meant to ascertain the existence of a correlation between its reduced biological functions and the presence of pollutants. Moreover, such biological systems act as accumulators and allow the detection and quantification of species present in the environment at low concentrations. Total reflection X-ray fluorescence analysis (TXRF) has been chosen for the investigation due to its high sensitivity, multielement capability and wide dynamic range. Corylus avellana L. (hazel) pollen has been collected in areas with different anthropic impact in the province of Trento, Italy. For the TXRF measurements, a liquid sample is needed, especially if a quantitative analysis is required. In the present work, the analysis after a microwave digestion has been compared with the analysis of a suspension of the pollen samples. In both cases, an internal standard has been used for the quantification. The concentrations of 17 elements ranging from Al to Pb have been determined in 13 samples. Analysis of the suspensions showed to be comparable to that of digested samples in terms of spectral quality, but the latter preparation method gave better reproducibility. Sub-ppm lowest limits of detection were obtained for iron and heavier elements detected.

  19. Determination of copper nanoparticle size distributions with total reflection X-ray fluorescence spectroscopy

    DOE PAGES

    Singh, Andy; Luening, Katharina; Brennan, Sean; ...

    2017-01-01

    Total reflection X-ray fluorescence (TXRF) analysis is extensively used by the semiconductor industry for measuring trace metal contamination on silicon surfaces. In addition to determining the quantity of impurities on a surface, TXRF can reveal information about the vertical distribution of contaminants by measuring the fluorescence signal as a function of the angle of incidence. In this study, two samples were intentionally contaminated with copper in non-deoxygenated and deoxygenated ultrapure water (UPW) resulting in impurity profiles that were either atomically dispersed in a thin film or particle-like, respectively. The concentration profile of the samples immersed into deoxygenated UPW was calculatedmore » using a theoretical concentration profile representative of particles, yielding a mean particle height of 16.1 nm. However, the resulting theoretical profile suggested that a distribution of particle heights exists on the surface. The fit of the angular distribution data was further refined by minimizing the residual error of a least-squares fit employing a model with a Gaussian distribution of particle heights about the mean height. The presence of a height distribution was also confirmed with atomic force microscopy measurements.« less

  20. Reflection nebulae in the Galactic center: soft X-ray imaging polarimetry

    NASA Astrophysics Data System (ADS)

    Marin, F.; Muleri, F.; Soffitta, P.; Karas, V.; Kunneriath, D.

    2015-04-01

    Context. The origin of irradiation and fluorescence of the 6.4 keV bright giant molecular clouds surrounding Sgr A∗, the central supermassive black hole of our Galaxy, remains enigmatic despite numerous attempts to decipher it with spectroscopic and timing analyses. Aims: Testing the theory of a past active period of Sgr A∗ requires opening a new observational window: X-ray polarimetry. In this paper, we aim to show how modern imaging polarimeters could revolutionize our understanding of the Galactic center (GC). Methods: Through Monte Carlo modeling, we produced a 4-8 keV polarization map of the GC. We focused on the polarimetric signature produced by Sgr B1, Sgr B2, G0.11-0.11, Bridge E, Bridge D, Bridge B2, MC2, MC1, Sgr C3, Sgr C2, and Sgr C1. We estimated the resulting polarization that arises from these scattering targets, included polarized flux dilution by the diffuse plasma emission detected toward the GC, and simulated the polarization map that modern polarimetric detectors would obtain assuming the performances of a mission prototype. Results: The eleven reflection nebulae we investigated present a variety of polarization signatures, ranging from nearly unpolarized to highly polarized (~77%) fluxes. Their polarization position angle is found to be normal to the scattering plane, as expected from previous studies. A major improvement in our simulation is the addition of a diffuse, unpolarized plasma emission that strongly affects soft X-ray polarized fluxes. The dilution factor is in the range 50%-70%, making the observation of the Bridge structure unlikely even in the context of modern polarimetry. The best targets are the Sgr B and Sgr C complexes and the G0.11-0.11 cloud, arranged in the order of decreasing detectability. Conclusions: An exploratory observation of a few hundred kilo-seconds of the Sgr B complex would allow a significant detection of the polarization and be sufficient to derive indications of the primary radiation source. A more

  1. Synchrotron Radiation Total Reflection X-ray Fluorescence Spectroscopy for Microcontamination Analysis on Silicon Wafer Surfaces

    SciTech Connect

    Takaura, Norikatsu

    1997-10-01

    As dimensions in state-of-the-art CMOS devices shrink to less than 0.1 pm, even low levels of impurities on wafer surfaces can cause device degradation. Conventionally, metal contamination on wafer surfaces is measured using Total Reflection X-Ray Fluorescence Spectroscopy (TXRF). However, commercially available TXRF systems do not have the necessary sensitivity for measuring the lower levels of contamination required to develop new CMOS technologies. In an attempt to improve the sensitivity of TXRF, this research investigates Synchrotron Radiation TXRF (SR TXRF). The advantages of SR TXRF over conventional TXRF are higher incident photon flux, energy tunability, and linear polarization. We made use of these advantages to develop an optimized SR TXRF system at the Stanford Synchrotron Radiation Laboratory (SSRL). The results of measurements show that the Minimum Detection Limits (MDLs) of SR TXRF for 3-d transition metals are typically at a level-of 3x10{sup 8} atoms/cm{sup 2}, which is better than conventional TXRF by about a factor of 20. However, to use our SR TXRF system for practical applications, it was necessary to modify a commercially available Si (Li) detector which generates parasitic fluorescence signals. With the modified detector, we could achieve true MDLs of 3x10{sup 8} atoms/cm{sup 2} for 3-d transition metals. In addition, the analysis of Al on Si wafers is described. Al analysis is difficult because strong Si signals overlap the Al signals. In this work, the Si signals are greatly reduced by tuning the incident beam energy below the Si K edge. The results of our measurements show that the sensitivity for Al is limited by x-ray Raman scattering. Furthermore, we show the results of theoretical modeling of SR TXRF backgrounds consisting of the bremsstrahlung generated by photoelectrons, Compton scattering, and Raman scattering. To model these backgrounds, we extended conventional theoretical models by taking into account several aspects particular

  2. Measurement of the effects of particulate contamination on X-ray reflectivity

    NASA Technical Reports Server (NTRS)

    Slane, P.; Mclaughlin, E. R.; Schwartz, D. A.; Van Speybroeck, L. P.; Bilbro, J. W.

    1989-01-01

    Because particles of sizes larger than a few tenths microns adversely affect high resolution X-ray telescopes by scattering and absorbing X-rays, the cleanliness required to maintain the about 1 percent overall calibration precision desired for the Advanced X-ray Astrophysics Facility (AXAF) is being investigated. At the grazing angles used for the AXAF mirrors, each particle shadows a surface area about 100 times its geometric area, necessitating glass occlusion specifications much more stringent than typically stipulated for visible-light particulate contamination. On test flats coated with gold, controlled levels of contamination have been deposited spanning the range from 5 x 10 to the -5th to 0.005 fractional area covered, and the absorption component of extinction has been measured over a range of grazing angles and X-ray energies to verify the predicted effects of particulate contamination.

  3. Theoretical consideration of an X-ray Bragg-reflection lens using the eikonal approximation.

    PubMed

    Balyan, Minas K

    2014-07-01

    On the basis of the eikonal approximation, X-ray Bragg-case focusing by a perfect crystal with parabolic-shaped entrance surface is considered theoretically. Expressions for focal distances, intensity gain and distribution around the focus spot as well as for the focus spot sizes are obtained. The condition of point focusing is presented. The experiment can be performed using X-ray synchrotron radiation sources (particularly free-electron lasers).

  4. Total reflection X-ray fluorescence trace mercury determination by trapping complexation: Application in advanced oxidation technologies

    NASA Astrophysics Data System (ADS)

    Custo, Graciela; Litter, Marta I.; Rodríguez, Diana; Vázquez, Cristina

    2006-11-01

    It is well known that Hg species cause high noxious effects on the health of living organisms even at very low levels (5 μg/L). Quantification of this element is an analytical challenge due to the peculiar physicochemical properties of all Hg species. The regulation of the maximal allowable Hg concentration led to search for sensitive methods for its determination. Total reflection X-ray fluorescence is a proved instrumental analytical tool for the determination of trace elements. In this work, the use of total reflection X-ray fluorescence for Hg quantification is investigated. However, experimental determination by total reflection X-ray fluorescence requires depositing a small volume of sample on the reflector and evaporation of the solvent until dryness to form a thin film. Because of volatilization of several Hg forms, a procedure to capture these volatile species in liquid samples by using complexing agents is proposed. Acetate, oxalic acid, ethylenediaminetetracetic acid and ammonium pyrrolidine-dithiocarbamate were assayed for trapping the analytes into the solution during the preparation of the sample and onto the reflector during total reflection X-ray fluorescence measurements. The proposed method was applied to evaluate Hg concentration during TiO 2-heterogeneous photocatalysis, one of the most known advanced oxidation technologies. Advanced oxidation technologies are processes for the treatment of effluents in waters and air that involve the generation of very active oxidative and reductive species. In heterogeneous photocatalysis, Hg is transformed to several species under ultraviolet illumination in the presence of titanium dioxide. Total reflection X-ray fluorescence was demonstrated to be applicable in following the extent of the heterogeneous photocatalysis reaction by determining non-transformed Hg in the remaining solution.

  5. X-ray Reflectivity Study of Ionic Liquids at Electrified Surfaces

    NASA Astrophysics Data System (ADS)

    Chu, Miaoqi

    X-ray reflectivity (XRR) versatile technique that characterize the surface structures. However, due to the lack of phase information of X-ray data, the reconstruction of electron density profile (EDP) from XRR data is an ill-posed inverse problem that requires extra attention. In Chapter 1, several key concepts in XRR data analysis are reviewed. The typical XRR data acquisition procedure and methods of modeling electron density are introduced. The widely used logarithm form of merit function is justified with mathematical deduction and numerical experiment. A scheme that generates artificial reflectivity data with theoretical statistical error but not systematical error is proposed. With the methods and schemes described in Chapter 1, simulated reflectivity data of a simple one-slab model is generated and fitted to test the efficient of EDP reconstruction. By isolating the parameters, the effects of slab width, electron density contrast and maximal wave transfer are studied individually. It?s demonstrated that best-fit/global minima, result reported by most XRR studies, don?t necessary reflect the real EDP. By contrast, mapping the merit function in the parametric space can capture much more details. Additionally, the widely accepted concept about the XRR theoretical spatial resolution (pi/q_{max}) as well the using Patterson function are brought to test. In the perspective of XRR data analysis, this chapter puts forward general rules to design and optimize XRR experiments. It also demonstrates how susceptible the fitting result will be if it?s not done carefully. In Chapter 3, the interface between hydrophobic OTS film and several solvents is studied with XRR in a transmission-cell setup. The solvents, from water, acetone, to alcohol (methanol, ethanol, 1-propanol), to alkane (pentane, hexane and heptane), vary significantly in terms of polarity and hydrogen bonding. However, the XRR data from different solvents are subtle. The methods and principles elicited in

  6. Understanding properties of engineered catalyst supports using contact angle measurements and X-Ray reflectivity

    NASA Astrophysics Data System (ADS)

    Amama, Placidus B.; Islam, Ahmad E.; Saber, Sammy M.; Huffman, Daniel R.; Maruyama, Benji

    2016-01-01

    There is significant interest in broadening the type of catalyst substrates that support the growth of high-quality carbon nanotube (CNT) carpets. In this study, ion beam bombardment has been utilized to modify catalyst substrates for CNT carpet growth. Using a combination of contact angle measurements (CAMs) and X-ray reflectivity (XRR) for the first time, new correlations between the physicochemical properties of pristine and engineered catalyst substrates and CNT growth behavior have been established. The engineered surfaces obtained after exposure to different degrees of ion beam damage have distinct physicochemical properties (porosity, layer thickness, and acid-base properties). The CAM data were analyzed using the van Oss-Chaudhury-Good model, enabling the determination of the acid-base properties of the substrate surfaces. For the XRR data, a Fourier analysis of the interference patterns enabled extraction of layer thickness, while the atomic density and interfacial roughness were extracted by analyzing the amplitude of the interference oscillations. The dramatic transformation of the substrate from ``inactive'' to ``active'' is attributed to a combined effect of substrate porosity or damage depth and Lewis basicity. The results reveal that the efficiency of catalyst substrates can be further improved by increasing the substrate basicity, if the minimum surface porosity is established. This study advances the use of a non-thermochemical approach for catalyst substrate engineering, as well as demonstrates the combined utility of CAM and XRR as a powerful, nondestructive, and reliable tool for rational catalyst design.There is significant interest in broadening the type of catalyst substrates that support the growth of high-quality carbon nanotube (CNT) carpets. In this study, ion beam bombardment has been utilized to modify catalyst substrates for CNT carpet growth. Using a combination of contact angle measurements (CAMs) and X-ray reflectivity (XRR) for the

  7. X-ray reflectivity on perfluoropolyether polymer molecules on amorphous carbon

    NASA Astrophysics Data System (ADS)

    Toney, Michael F.; Thompson, Carol

    1990-03-01

    The mass density profile from thin (˜25 Å) layers of polymer molecules adsorbed on amorphous carbon thin films is determined from measurements of the specular reflectivity of x rays. Important information on the conformation of the polymer molecules is obtained from the density profile (average density as a function of position above the surface). The polymer is a perfluoropolyether (PFPE) with piperonyl end groups and has a molecular weight of 2000-3000 Daltons. Three samples are measured: a nonbonded sample with an approximately 25 Å layer applied by dipping, a bonded sample with the layer applied by dipping but followed by a process to attach the molecule to the carbon, and a cleaned sample which is the nonbonded sample after the polymer had been removed. The density profile of the nonbonded polymer shows that the density within 10 Å of the carbon surface is ˜1.6 gm/cc, which is smaller than the density in the region between 10 and 25 Å (˜1.8 gm/cc). This indicates that the less dense piperonyl end groups are preferentially adsorbed near the carbon surface, which provides a possible explanation of the observation that the addition of the piperonyl end group to PFPE improves adhesion of the polymer to surfaces. The bulk-like density in the region between 10 and 25 Å and the compactness of the layer suggest that the preponderance of molecules have both end groups preferentially adsorbed; consequently, the PFPE chains remain close to the surface. The data from the bonded and nonbonded polymer layers are essentially the same, which indicates the molecular conformation is not strongly affected by the bonding treatment.

  8. Total reflection of x-ray fluorescence (TXRF): a mature technique for environmental chemical nanoscale metrology

    NASA Astrophysics Data System (ADS)

    Borgese, L.; Zacco, A.; Bontempi, E.; Colombi, P.; Bertuzzi, R.; Ferretti, E.; Tenini, S.; Depero, L. E.

    2009-08-01

    Total reflection x-ray fluorescence (TXRF) is a technique well established for chemical analysis of samples deposited as a thin layer. Nowadays it is mainly employed for electronic industry quality control. Recently, very compact and economic TXRF instrumentation was proposed. Combining this with the capability to analyze liquid samples, this technique is suitable to be employed in many different applications, comprising the very critical field of environmental analysis. Comparisons with the standard atomic absorption spectroscopy (AAS) technique show that TXRF is a practical, accurate, and reliable technique. Indeed, round-robin activities have already been started. Despite the efficiency and economy of the developed portable TXRF instrumentation, this is not widely employed for chemical laboratory analysis probably because TXRF is not an officially recognized technique, i.e. it is not yet normative-subjected. This fact could also be due to the long background of analytical applications developed for AAS, ICPS or inductively coupled plasma mass spectroscopy (ICP-MS) up to now. In this paper, we present a work of environmental monitoring of an industrial site, performed by means of bioindicators (lichens). The analysis of trace elements concentration in lichen was usually conducted with spectrophotometric techniques, such as AAS and ICP-MS, which were accepted by common regulations and normative-subjected. In this study, we accomplished a comparative lichen analysis by AAS and TXRF. The reproducibility of the obtained results showed the high correspondence between the two techniques. This comparison highlighted the versatility of the TXRF apparatus that allowed more rapid and simultaneous element detection. The obtained results suggested that this portable TXRF system could be suitable for regulation to produce certificated analysis upto ppb concentrations for some elements.

  9. High order reflectivity of graphite (HOPG) crystals for x ray energies up to 22 keV

    SciTech Connect

    Doeppner, T; Neumayer, P; Girard, F; Kugland, N L; Landen, O L; Niemann, C; Glenzer, S H

    2008-04-30

    We used Kr K{alpha} (12.6 keV) and Ag K{alpha} (22.1 keV) x-rays, produced by petawatt class laser pulses interacting with a Kr gas jet and a silver foil, to measure the integrated crystal reflectivity of flat Highly Oriented Pyrolytic Graphite (HOPG) up to fifth order. The reflectivity in fourth order is lower by a factor of 50 when compared to first order diffraction. In second order the integrated reflectivity decreases from 1.3 mrad at 12.6 keV to 0.5 mrad at 22.1 keV. The current study indicates that HOPG crystals are suitable for measuring scattering signals from high energy x ray sources (E {ge} 20 keV). These energies are required to penetrate through the high density plasma conditions encountered in inertial confinement fusion capsule implosions on the National Ignition Facility.

  10. X-ray reflection from black-hole accretion discs with a radially stratified ionisation

    NASA Astrophysics Data System (ADS)

    Svoboda, J.; Domcek, V.; Dovčiak, M.; Guainazzi, M.; Marinucci, A.

    2015-07-01

    Recent X-ray observations have suggested a very high compactness of coronae in Active Galactic Nuclei as well as in X-ray Binaries. The compactness of the source implies that the black-hole accretion disc irradiation is a strong function of radius. We will show how the X-ray spectra are modified assuming the radially stratified ionisation according to the illumination by a point-like source on the black-hole rotational axis. We will discuss how this affects the measurements of the other model parameters, such as spin and radial emissivity. We will show the application of this model to the recent XMM-Newton/NUSTAR data of an active galaxy MCG-6-30-15.

  11. Image quality improvement in a hard X-ray projection microscope using total reflection mirror optics.

    PubMed

    Mimura, Hidekazu; Yamauchi, Kazuto; Yamamura, Kazuya; Kubota, Akihisa; Matsuyama, Satoshi; Sano, Yasuhisa; Ueno, Kazumasa; Endo, Katsuyoshi; Nishino, Yoshinori; Tamasaku, Kenji; Yabashi, Makina; Ishikawa, Tetsuya; Mori, Yuzo

    2004-07-01

    A new figure correction method has been applied in order to fabricate an elliptical mirror to realize a one-dimensionally diverging X-ray beam having high image quality. Mutual relations between figure errors and intensity uniformities of diverging X-ray beams have also been investigated using a wave-optical simulator and indicate that figure errors in relatively short spatial wavelength ranges lead to high-contrast interference fringes. By using a microstitching interferometer and elastic emission machining, figure correction of an elliptical mirror with a lateral resolution close to 0.1 mm was carried out. A one-dimensional diverging X-ray obtained using the fabricated mirror was observed at SPring-8 and evaluated to have a sufficiently flat intensity distribution.

  12. Relative angle determinable stitching interferometry for hard x-ray reflective optics

    SciTech Connect

    Mimura, Hidekazu; Yumoto, Hirokatsu; Matsuyama, Satoshi; Yamamura, Kazuya; Sano, Yasuhisa; Ueno, Kazumasa; Endo, Katsuyoshi; Mori, Yuzo; Yabashi, Makina; Tamasaku, Kenji; Nishino, Yoshinori; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2005-04-01

    Metrology plays an important role in surface figuring with subnanometer accuracy. We have developed relative angle determinable stitching interferometry for the surface figuring of elliptical mirrors, in order to realize hard x-ray nanofocusing. In a stitching system, stitching angles are determined not by the general method using a common area between neighboring shots, but by the new method using the mirror's tilt angles measured at times when profile data are acquired. The high measurement accuracy of approximately 4 nm (peak-to-valley) was achieved in the measurement of a cylindrical surface having the same curvature as the elliptically designed shape to enable hard x-ray nanofocusing.

  13. Reflective multilayer optic as hard X-ray diagnostic on laser-plasma experiment.

    PubMed

    Brejnholt, N F; Decker, T A; Hill, R M; Chen, H; Williams, G J; Park, J; Alameda, J B; Fernández-Perea, M; Pivovaroff, M J; Soufli, R; Descalle, M-A; Peebles, J; Kerr, S M

    2015-01-01

    A multilayer-based optic was tested for use as an X-ray diagnostic on a laser-plasma experiment. The multilayer optic was employed to selectively pass X-rays between 55 and 100 keV. An order of magnitude improvement in signal-to-noise ratio is achieved compared to a transmission crystal spectrometer. A multilayer response model, taking into account the source size and spectral content, is constructed and the outlook for application above 500 keV is briefly discussed. LLNL-JRNL-664311.

  14. Structural investigations of self-assembled monolayers for organic electronics: results from X-ray reflectivity.

    PubMed

    Khassanov, Artoem; Steinrück, Hans-Georg; Schmaltz, Thomas; Magerl, Andreas; Halik, Marcus

    2015-07-21

    Self-assembled monolayers (SAMs) have been established as crucial interlayers and electronically active layers in organic electronic devices, such as organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), organic thin film transistors (OTFTs), and nonvolatile memories (NVMs). The use of self-assembling functionalized organic molecules is beneficial due to mainly three advantages compared with common thin film deposition approaches. (1) Molecular self-assembly occurs with surface selectivity, determined by the interaction between the functional anchor group of the organic molecules and the target surface. (2) The film thickness of the resulting layers is perfectly controllable on the angstrom scale, due to the self-terminating film formation to only a single molecular layer. And finally, (3) the wide variability in the chemical structure of such molecules enables different SAM functionalities for devices, ranging from electrical insulation to charge storage to charge transport. The SAM approach can be further expanded by employing several functionalized molecules to create mixed SAMs with consequently mixed properties. The function of SAMs in devices depends not only on the chemical structure of the molecules but also on their final arrangement and orientation on the surface. A reliable and nondestructive in-depth characterization of SAMs on nonconductive oxide surfaces is still challenging because of the very small thickness and the impracticality of methods such as scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). In this Account, we illustrate how X-ray reflectivity (XRR) provides analytical access to major questions of SAM composition, morphology, and even formation by means of investigations of pure and mixed SAMs based on phosphonic acids (PAs) of various chain structures on flat alumina (AlOx) surfaces. XRR is an analytical method that provides access to spatially averaged structural depth profiles over a relatively

  15. Using in situ X-ray reflectivity to study protein adsorption on hydrophilic and hydrophobic surfaces: benefits and limitations.

    PubMed

    Richter, Andrew G; Kuzmenko, Ivan

    2013-04-30

    We have employed in situ X-ray reflectivity (IXRR) to study the adsorption of a variety of proteins (lysozyme, cytochrome c, myoglobin, hemoglobin, serum albumin, and immunoglobulin G) on model hydrophilic (silicon oxide) and hydrophobic surfaces (octadecyltrichlorosilane self-assembled monolayers), evaluating this recently developed technique for its applicability in the area of biomolecular studies. We report herein the highest resolution depiction of adsorbed protein films, greatly improving on the precision of previous neutron reflectivity (NR) results and previous IXRR studies. We were able to perform complete scans in 5 min or less with the maximum momentum transfer of at least 0.52 Å(-1), allowing for some time-resolved information about the evolution of the protein film structure. The three smallest proteins (lysozyme, cytochrome c, and myoglobin) were seen to deposit as fully hydrated, nondenatured molecules onto hydrophilic surfaces, with indications of particular preferential orientations. Time evolution was observed for both lysozyme and myoglobin films. The larger proteins were not observed to deposit on the hydrophilic substrates, perhaps because of contrast limitations. On hydrophobic surfaces, all proteins were seen to denature extensively in a qualitatively similar way but with a rough trend that the larger proteins resulted in lower coverage. We have generated high-resolution electron density profiles of these denatured films, including capturing the growth of a lysozyme film. Because the solution interface of these denatured films is diffuse, IXRR cannot unambiguously determine the film extent and coverage, a drawback compared to NR. X-ray radiation damage was systematically evaluated, including the controlled exposure of protein films to high-intensity X-rays and exposure of the hydrophobic surface to X-rays before adsorption. Our analysis showed that standard measuring procedures used for XRR studies may lead to altered protein films

  16. Recent results of synchrotron radiation induced total reflection X-ray fluorescence analysis at HASYLAB, beamline L

    NASA Astrophysics Data System (ADS)

    Streli, C.; Pepponi, G.; Wobrauschek, P.; Jokubonis, C.; Falkenberg, G.; Záray, G.; Broekaert, J.; Fittschen, U.; Peschel, B.

    2006-11-01

    At the Hamburger Synchrotronstrahlungslabor (HASYLAB), Beamline L, a vacuum chamber for synchrotron radiation-induced total reflection X-ray fluorescence analysis, is now available which can easily be installed using the adjustment components for microanalysis present at this beamline. The detector is now in the final version of a Vortex silicon drift detector with 50-mm 2 active area from Radiant Detector Technologies. With the Ni/C multilayer monochromator set to 17 keV extrapolated detection limits of 8 fg were obtained using the 50-mm 2 silicon drift detector with 1000 s live time on a sample containing 100 pg of Ni. Various applications are presented, especially of samples which are available in very small amounts: As synchrotron radiation-induced total reflection X-ray fluorescence analysis is much more sensitive than tube-excited total reflection X-ray fluorescence analysis, the sampling time of aerosol samples can be diminished, resulting in a more precise time resolution of atmospheric events. Aerosols, directly sampled on Si reflectors in an impactor were investigated. A further application was the determination of contamination elements in a slurry of high-purity Al 2O 3. No digestion is required; the sample is pipetted and dried before analysis. A comparison with laboratory total reflection X-ray fluorescence analysis showed the higher sensitivity of synchrotron radiation-induced total reflection X-ray fluorescence analysis, more contamination elements could be detected. Using the Si-111 crystal monochromator also available at beamline L, XANES measurements to determine the chemical state were performed. This is only possible with lower sensitivity as the flux transmitted by the crystal monochromator is about a factor of 100 lower than that transmitted by the multilayer monochromator. Preliminary results of X-ray absorption near-edge structure measurements for As in xylem sap from cucumber plants fed with As(III) and As(V) are reported. Detection limits

  17. Determination of observable depth of dislocations in 4H-SiC by X-ray topography in back reflection

    NASA Astrophysics Data System (ADS)

    Ishiji, Kotaro; Kawado, Seiji; Hirai, Yasuharu; Nagamachi, Shinji

    2017-10-01

    We performed X-ray topography using the asymmetric \\bar{1}\\bar{1}28 back-reflection by changing the incident X-ray energy (E) in order to evaluate the observable depth (t obs) of dislocations in 4H-SiC(0001) wafers with a 4° off-axis angle toward the [11\\bar{2}0]-direction. Since the incident angle (ω) of the X-rays satisfying the Bragg condition changed along with E, the observable length of the straight segment of the basal plane dislocation (BPD) on the X-ray topographs also changed. The t obs values were determined from the observable length of the straight BPD segment, and consequently, plots of t obs versus E, and t obs versus ω were obtained. We discussed the relationships between t obs and the absorption depth (t μ), between t obs and the extinction depth (t Λ), and between t obs and t Λ/t μ as criteria of the dislocation visibility, and we found that the plot of t obs versus t μ was described as t obs ∼ 0.75t μ with good linearity.

  18. Pigment particles analysis with a total reflection X-ray fluorescence spectrometer: study of influence of instrumental parameters

    NASA Astrophysics Data System (ADS)

    Coccato, Alessia; Vekemans, Bart; Vincze, Laszlo; Moens, Luc; Vandenabeele, Peter

    2016-12-01

    Total reflection X-ray fluorescence (TXRF) analysis is an excellent tool to determine major, minor and trace elements in minuscule amounts of samples, making this technique very suitable for pigment analysis. Collecting minuscule amounts of pigment material from precious works of art by means of a cotton swab is a well-accepted sampling method, but poses specific challenges when TXRF is to be used for the characterization of the unknown material.

  19. Depth resolved compositional analysis of aluminium oxide thin film using non-destructive soft x-ray reflectivity technique

    NASA Astrophysics Data System (ADS)

    Sinha, Mangalika; Modi, Mohammed H.

    2017-10-01

    In-depth compositional analysis of 240 Å thick aluminium oxide thin film has been carried out using soft x-ray reflectivity (SXR) and x-ray photoelectron spectroscopy technique (XPS). The compositional details of the film is estimated by modelling the optical index profile obtained from the SXR measurements over 60-200 Å wavelength region. The SXR measurements are carried out at Indus-1 reflectivity beamline. The method suggests that the principal film region is comprised of Al2O3 and AlOx (x = 1.6) phases whereas the interface region comprised of SiO2 and AlOx (x = 1.6) mixture. The soft x-ray reflectivity technique combined with XPS measurements explains the compositional details of principal layer. Since the interface region cannot be analyzed with the XPS technique in a non-destructive manner in such a case the SXR technique is a powerful tool for nondestructive compositional analysis of interface region.

  20. Total-reflection X-ray fluorescence — a tool to obtain information about different air masses and air pollution

    NASA Astrophysics Data System (ADS)

    Schmeling, Martina

    2001-11-01

    Atmospheric aerosols are solid particles dissolved in air and change their chemical composition frequently depending on various parameters. In order to identify regional air circulation atmospheric aerosol filter samples were taken at Loyola University Chicago's Lake Shore Campus during the months of July and August 2000 with sampling times ranging between 1 and 2 h. The samples were digested in a microwave oven and analyzed by total-reflection X-ray fluorescence (TXRF) spectrometry. One diurnal variation comprising five consecutive sampling events was selected and discussed as well as 4 days experiencing different meteorology were compared to exemplify the variation in trace elemental concentration according to air mass movements and highlight the capability of total-reflection X-ray fluorescence analysis. It was found that due to changes in meteorological conditions particularly wind direction and wind speed, trace elemental compositions varied rapidly and could be used to distinguish between 'Lake Michigan air' and 'metropolitan Chicago air' on such short-term time scale like one hour. Back trajectory analysis was applied to support and corroborate the results. The outcome of this study clearly shows that total-reflection X-ray fluorescence is an optimal tool for analysis of atmospheric aerosols.

  1. X-ray Reflected Spectra from Accretion Disk Models. I. Constant Density Atmospheres

    NASA Technical Reports Server (NTRS)

    Garcia, Javier; Kallman, Timothy R.

    2009-01-01

    We present new models for illuminated accretion disks, their structure and reprocessed emission. We consider the effects of incident X-rays on the surface of an accretion disk by solving simultaneously the equations of radiative transfer, energy balance and ionization equilibrium over a large range of column densities. We assume plane-parallel geometry and azimuthal symmetry, such that each calculation corresponds to a ring at a given distance from the central object. Our models include recent and complete atomic data for K-shell of the iron and oxygen isonuclear sequences. We examine the effect on the spectrum of fluorescent Ka line emission and absorption in the emitted spectrum. We also explore the dependence of the spectrum on the strength of the incident X-rays and other input parameters, and discuss the importance of Comptonization on the emitted spectrum.

  2. [Synchrotron studies of x-ray reflectivity from surfaces]. Technical progress report

    SciTech Connect

    Pershan, P.S.

    1992-03-03

    Following a long period of theoretical interest, but only limited measurements, there has recently been an increased number of attempts to expand the relative paucity of experimental information on the structure of liquid surfaces using techniques as diverse as ellipsometry, micro-force balances, non-linear optics, Auger and photoelectron spectroscopy, and x-ray scattering. Our group has played a leading role in the currently expanding application of scattering techniques to the general problem of characterizing the microscopic structure of liquid surfaces and we propose here that this work be extended specifically to liquid metals. In the following sections we will briefly describe the salient features of x-ray scattering that are relevant to the current project, the progress that we have made in the current grant period and the work that we propose to carry out in the forthcoming grant period.

  3. Silicon loss metrology using synchrotron x-ray reflectance and Bragg diffraction

    SciTech Connect

    Bhargava, Mansi; Wolfe, John C.; Donner, Wolfgang; Srivastava, Aseem

    2007-09-26

    We use synchrotron x-ray reflectometry and Bragg diffraction to study silicon loss in the low temperature plasma oxidation of silicon-on-insulator (SOI) wafers. We show that Laue oscillations associated with the Si (004) Bragg peak give the number of Si (004) planes in the device layer to within an experimental error of 0.07 nm and that X-ray reflectometry gives the total thickness of the device layer and the surface oxide to within 0.05 nm. We find that silicon loss in samples processed in two different plasma systems correspond to an increase in total thickness that is consistent with the formation of SiO{sub 2}.

  4. At-wavelength figure metrology of total reflection mirrors in hard x-ray region

    NASA Astrophysics Data System (ADS)

    Yumoto, Hirokatsu; Mimura, Hidekazu; Matsuyama, Satoshi; Handa, Soichiro; Shibatani, Akihiko; Katagishi, Keiko; Sano, Yasuhisa; Yabashi, Makina; Nishino, Yoshinori; Tamasaku, Kenji; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2006-08-01

    We realized nearly diffraction-limited performance with a FWHM focal spot size of 25 nm at an x-ray energy of 15 keV at SPring-8. We explain performances of fabricated x-ray mirror, its fabrication technologies and future plan for realizing sub-10-nm focusing. We developed a novel method of at-wavelength metrology for evaluating the focusing hard x-ray beam in a grazing-incidence optical system. The metrology is based on the numerical retrieval method using the intensity distribution profile around the focal point. We demonstrated the at-wavelength metrology and estimated the surface figure error on a test mirror. An experiment for measuring the focusing intensity profile was performed at the 1-km-long beamline (BL29XUL) of SPring-8. The obtained results were compared with the profile measured by the optical interferometer and confirmed to be in good agreement with it. This technique has potential for characterizing wave-front aberration on elliptical mirrors for the sub-10-nm focusing.

  5. Is SS 433 a misaligned ultraluminous X-ray source? Constraints from its reflected signal in the Galactic plane

    NASA Astrophysics Data System (ADS)

    Khabibullin, I.; Sazonov, S.

    2016-04-01

    We evaluate the emission that must arise due to reflection of the putative collimated X-ray radiation of SS 433 by atomic gas and molecular clouds in the Galactic plane and compare the predicted signal with existing RXTE and ASCA data for the region of interest. Assuming that the intrinsic X-ray spectrum of SS 433 is similar to that of ultraluminous X-ray sources (ULXs), we obtain an upper limit of ˜2 × 1039 erg s-1 on its total (angular-integrated) luminosity in the 2-10 keV energy band, which is only weakly dependent on the half-opening angle, Θr, of the emission cone. In contrast, the upper limit on the apparent luminosity of SS 433 (that would be perceived by an observer looking at its supercritical accretion disc face-on) decreases with increasing Θr and is ˜3 × 1040 erg s-1 for Θr ≳ Θp = 21°, where Θp is the precession angle of the baryonic jets (assuming that the emission cones precess in the same manner as the jets). This leaves open the possibility that SS 433 is a misaligned ULX. Further investigation of the reflection signal from the molecular clouds using higher angular resolution observations could improve these constraints with the potential to break the degeneracy between Θr and the apparent luminosity.

  6. Surface structure of the liquid Au[subscript 72]Ge[subscript 28] eutectic phase: X-ray reflectivity

    SciTech Connect

    Pershan, P.S.; Stoltz, S.E.; Mechler, S.; Shpyrko, O.G.; Grigoriev, A.Y.; Balagurusamy, V.S. K.; Lin, B.H.; Meron, M.

    2009-12-01

    The surface structure of the liquid phase of the Au{sub 72}Ge{sub 28} eutectic alloy has been measured using resonant and nonresonant x-ray reflectivity and grazing incidence x-ray diffraction. In spite of the significant differences in the surface tension of liquid Ge and Au the Gibbs adsorption enhancement of Ge concentration at the surface is minimal. This is in striking contrast to all the other binary alloys with large differences in the respective surface tensions measured up to date. In addition there is no evidence of the anomalous strong surface layering or in-plane crystalline order that has been reported for the otherwise quite similar liquid Au{sub 82}Si{sub 18} eutectic. Instead, the surface of eutectic Au{sub 72}Ge{sub 28} is liquidlike and the layering can be explained by the distorted crystal model with only slight modifications to the first layer.

  7. Experimental and analysis considerations for transmission/reflection spectrograms used in ultrafast x-ray pulse diagnostics

    NASA Astrophysics Data System (ADS)

    Kane, Daniel J.; Hartmann, Nick; Coffee, Ryan N.; Fry, Alan R.

    2016-03-01

    Ultrafast time-dependent optical reflection and/or transmission spectroscopy can be used to measure time responses of materials and time arrivals between two unrelated ultrafast pulses. For example, a pump pulse, such as an x-ray pulse, excites a material, changing its refractive index. A spectrogram monitoring the change of intensity of a reflected or transmitted optical probe pulse can be used to indirectly monitor the refractive index change. Standard spectrogram deconvolution methods can be used to extract characteristics of both the material response and the probe pulse, but care must be taken to consider any experimental artifacts.

  8. X-ray beamsplitter

    DOEpatents

    Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

    1987-08-07

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

  9. X-ray beamsplitter

    DOEpatents

    Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

    1989-01-01

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

  10. NUSTAR and SUZAKU X-ray spectroscopy of NGC 4151: Evidence for reflection from the inner accretion disk

    DOE PAGES

    Keck, M. L.; Brenneman, L. W.; Ballantyne, D. R.; ...

    2015-06-15

    We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spinmore » $$a\\gt 0.9$$ accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection (IDR) flux variation drives the spectral variability during the observations. As a result, we discuss various physical scenarios for the IDR model and we find that a compact corona is consistent with the observed features.« less

  11. NuSTAR and Suzaku X-ray Spectroscopy of NGC 4151: Evidence for Reflection from the Inner Accretion Disk

    NASA Astrophysics Data System (ADS)

    Keck, M. L.; Brenneman, L. W.; Ballantyne, D. R.; Bauer, F.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Dauser, T.; Elvis, M.; Fabian, A. C.; Fuerst, F.; García, J.; Grefenstette, B. W.; Hailey, C. J.; Harrison, F. A.; Madejski, G.; Marinucci, A.; Matt, G.; Reynolds, C. S.; Stern, D.; Walton, D. J.; Zoghbi, A.

    2015-06-01

    We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spin a\\gt 0.9 accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection (IDR) flux variation drives the spectral variability during the observations. We discuss various physical scenarios for the IDR model and we find that a compact corona is consistent with the observed features.

  12. X-ray diffraction from flight muscle with a headless myosin mutation: implications for interpreting reflection patterns

    PubMed Central

    Iwamoto, Hiroyuki; Trombitás, Károly; Yagi, Naoto; Suggs, Jennifer A.; Bernstein, Sanford I.

    2014-01-01

    Fruit fly (Drosophila melanogaster) is one of the most useful animal models to study the causes and effects of hereditary diseases because of its rich genetic resources. It is especially suitable for studying myopathies caused by myosin mutations, because specific mutations can be induced to the flight muscle-specific myosin isoform, while leaving other isoforms intact. Here we describe an X-ray-diffraction-based method to evaluate the structural effects of mutations in contractile proteins in Drosophila indirect flight muscle. Specifically, we describe the effect of the headless myosin mutation, Mhc10-Y97, in which the motor domain of the myosin head is deleted, on the X-ray diffraction pattern. The loss of general integrity of the filament lattice is evident from the pattern. A striking observation, however, is the prominent meridional reflection at d = 14.5 nm, a hallmark for the regularity of the myosin-containing thick filament. This reflection has long been considered to arise mainly from the myosin head, but taking the 6th actin layer line reflection as an internal control, the 14.5-nm reflection is even stronger than that of wild-type muscle. We confirmed these results via electron microscopy, wherein image analysis revealed structures with a similar periodicity. These observations have major implications on the interpretation of myosin-based reflections. PMID:25400584

  13. NUSTAR and Suzaku x-ray spectroscopy of NGC 4151: Evidence for reflection from the inner accretion disk

    SciTech Connect

    Keck, M. L.; Brenneman, L. W.; Ballantyne, D. R.; Bauer, F.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Dauser, T.; Elvis, M.; Fabian, A. C.; Fuerst, F.; García, J.; Grefenstette, B. W.; Hailey, C. J.; Harrison, F. A.; Madejski, G.; Marinucci, A.; Matt, G.; Reynolds, C. S.; Stern, D.; Walton, D. J.; Zoghbi, A.

    2015-06-15

    We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spin $a\\gt 0.9$ accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection (IDR) flux variation drives the spectral variability during the observations. We discuss various physical scenarios for the IDR model and we find that a compact corona is consistent with the observed features.

  14. Determination of trace elements in bee honey, pollen and tissue by total reflection and radioisotope X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Kump, P.; Nečemer, M.; Šnajder, J.

    1996-04-01

    Multielemental determinations in samples of various types of bee honey, pollen and bee tissue have been carried out using total reflection X-ray fluorescence spectrometry (TXRF) and radioisotope excited X-ray fluorescence spectrometry (XRF). The objective was to establish whether the elemental content of bee honey, in particular, correlates with any useful information about the environment, variety of honey, etc. An attempt has also been made to determine the X-ray techniques' ability to compete with atomic absorption spectrometry (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES), with regard to elemental sensitivity, accuracy, sample preparation procedures, and in particular, economic performance, which is very important in selecting an appropriate technique for the analysis of large numbers of samples. The results confirm the advantages of the TXRF method for trace element analysis, but only when utilising monochromatic excitation and selecting a proper sample preparation procedure. The radioisotope XRF technique, which does not require any sample preparation, is still very competitive in analysis of elements with concentrations above a few ten ppm. Preliminary results also confirm some correlations between the elemental content of honey and the status of the environment, and encourage further work in this direction

  15. The X-Ray Reflection Spectrum of the Radio-loud Quasar 4C 74.26

    NASA Astrophysics Data System (ADS)

    Lohfink, Anne M.; Fabian, Andrew C.; Ballantyne, David R.; Boggs, S. E.; Boorman, Peter; Christensen, F. E.; Craig, W. W.; Farrah, Duncan; García, Javier; Hailey, C. J.; Harrison, F. A.; Ricci, Claudio; Stern, Daniel; Zhang, W. W.

    2017-06-01

    The relativistic jets created by some active galactic nuclei are important agents of AGN feedback. In spite of this, our understanding of what produces these jets is still incomplete. X-ray observations, which can probe the processes operating in the central regions in the immediate vicinity of the supermassive black hole, the presumed jet launching point, are potentially particularly valuable in illuminating the jet formation process. Here, we present the hard X-ray NuSTAR observations of the radio-loud quasar 4C 74.26 in a joint analysis with quasi-simultaneous, soft X-ray Swift observations. Our spectral analysis reveals a high-energy cutoff of {183}-35+51 keV and confirms the presence of ionized reflection in the source. From the average spectrum we detect that the accretion disk is mildly recessed, with an inner radius of R in = 4-180 R g. However, no significant evolution of the inner radius is seen during the three months covered by our NuSTAR campaign. This lack of variation could mean that the jet formation in this radio-loud quasar differs from what is observed in broad-line radio galaxies.

  16. 50-nm-resolution full-field X-ray microscope without chromatic aberration using total-reflection imaging mirrors

    PubMed Central

    Matsuyama, Satoshi; Yasuda, Shuhei; Yamada, Jumpei; Okada, Hiromi; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2017-01-01

    X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrick–Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range. Here, we present an optical system consisting of two monolithic imaging mirrors. Elliptic and hyperbolic shapes were formed on a single substrate to achieve both high resolution and sufficient stability. The mirrors were finished with a ~1-nm shape accuracy using elastic emission machining. The performance was tested at SPring-8 with a photon energy of approximately 10 keV. We could clearly resolve 50-nm features in a Siemens star without chromatic aberration and with high stability over 20 h. We applied this system to X-ray absorption fine structure spectromicroscopy and identified elements and chemical states in specimens of zinc and tungsten micron-size particles. PMID:28406227

  17. 50-nm-resolution full-field X-ray microscope without chromatic aberration using total-reflection imaging mirrors.

    PubMed

    Matsuyama, Satoshi; Yasuda, Shuhei; Yamada, Jumpei; Okada, Hiromi; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2017-04-13

    X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrick-Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range. Here, we present an optical system consisting of two monolithic imaging mirrors. Elliptic and hyperbolic shapes were formed on a single substrate to achieve both high resolution and sufficient stability. The mirrors were finished with a ~1-nm shape accuracy using elastic emission machining. The performance was tested at SPring-8 with a photon energy of approximately 10 keV. We could clearly resolve 50-nm features in a Siemens star without chromatic aberration and with high stability over 20 h. We applied this system to X-ray absorption fine structure spectromicroscopy and identified elements and chemical states in specimens of zinc and tungsten micron-size particles.

  18. 50-nm-resolution full-field X-ray microscope without chromatic aberration using total-reflection imaging mirrors

    NASA Astrophysics Data System (ADS)

    Matsuyama, Satoshi; Yasuda, Shuhei; Yamada, Jumpei; Okada, Hiromi; Kohmura, Yoshiki; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2017-04-01

    X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrick-Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range. Here, we present an optical system consisting of two monolithic imaging mirrors. Elliptic and hyperbolic shapes were formed on a single substrate to achieve both high resolution and sufficient stability. The mirrors were finished with a ~1-nm shape accuracy using elastic emission machining. The performance was tested at SPring-8 with a photon energy of approximately 10 keV. We could clearly resolve 50-nm features in a Siemens star without chromatic aberration and with high stability over 20 h. We applied this system to X-ray absorption fine structure spectromicroscopy and identified elements and chemical states in specimens of zinc and tungsten micron-size particles.

  19. The X-Ray Reflection Spectrum of the Radio-Loud Quasar 4C 74.26

    NASA Technical Reports Server (NTRS)

    Lohfink, Ann M.; Fabian, Andrew C.; Ballantyne, David R.; Boggs, S. E.; Boorman, Peter; Christensen, F. E.; Craig, W. W.; Farrah, Duncan; Garcia, Javier; Hailey, C. J.; hide

    2017-01-01

    The relativistic jets created by some active galactic nuclei are important agents of AGN feedback. In spite of this, our understanding of what produces these jets is still incomplete. X-ray observations, which can probe the processes operating in the central regions in the immediate vicinity of the supermassive black hole, the presumed jet launching point, are potentially particularly valuable in illuminating the jet formation process. Here, we present the hard X-ray NuSTAR observations of the radio-loud quasar 4C 74.26 in a joint analysis with quasi-simultaneous, soft X-ray Swift observations. Our spectral analysis reveals a high-energy cutoff of -183+3551 keV and confirms the presence of ionized reflection in the source. From the average spectrum we detect that the accretion disk is mildly recessed, with an inner radius of Rin4180 Rg. However, no significant evolution of the inner radius is seen during the three months covered by our NuSTAR campaign. This lack of variation could mean that the jet formation in this radio-loud quasar differs from what is observed in broad-line radio galaxies.

  20. Reflectance enhancement in the extreme ultraviolet and soft x rays by means of multilayers with more than two materials.

    PubMed

    Larruquert, Juan I

    2002-02-01

    Sub-quarterwave multilayer coatings with more than two different materials are shown to provide a reflectance enhancement compared with the standard two-material multilayer coatings when reflectance is limited by material absorption. A remarkable reflectance enhancement is obtained when the materials in the multilayer are moderately absorbing. A simple rule based on the material optical constants is provided to select the most suitable materials for the multilayer and to arrange the materials in the correct sequence in order to obtain the highest possible reflectance. It is shown that sub-quarterwave multilayers generalize the concept of multilayers, of which the standard two-material multilayers are a particular case. Various examples illustrate the benefit of sub-quarter-wave multilayer coatings for highest reflectance in the extreme ultraviolet. Applications for sub-quarterwave multilayer coatings are envisaged for astronomy in the extreme ultraviolet (EUV) and soft x rays and also for future EUY lithography.

  1. Hygrothermal degradation of 3-glycidoxypropyltrimethoxysilane films studied by neutron and X-ray reflectivity and attenuated total reflection infrared spectroscopy.

    SciTech Connect

    Tallant, David Robert; Garcia, Manuel Joseph; Majewski, Jaroslaw; Kent, Michael Stuart; Yim, Hyun

    2005-05-01

    Thin films of organosilanes have great technological importance in the areas of adhesion promotion, durability, and corrosion resistance. However, it is well-known that water can degrade organosilane films, particularly at elevated temperatures. In this work, X-ray and neutron reflectivity (XR and NR) were combined with attenuated total reflection infrared (ATR-IR) spectroscopy to study the chemical and structural changes within thin films of (3-glycidoxypropyl)trimethoxysilane (GPS) after exposure for various periods of time to air saturated with either D{sub 2}O or H{sub 2}O at 80 C. For NR and XR, ultrathin ({approx}100 {angstrom}) films were prepared by spin-coating. Both D{sub 2}O and H{sub 2}O provide neutron scattering contrast with GPS. Variations in the neutron scattering length density (SLD) profiles (a function of mass density and atomic composition) with conditioning time were measured after drying the samples out and also swelled with H{sub 2}O or D{sub 2}O vapor at room temperature. For samples that were dried out prior to measurement, little or no change was observed for H{sub 2}O conditioning up to 3.5 days, but large changes were observed after 30 days of conditioning. The range of conditioning time for this structural change was narrowed to between 4 and 10 days with XR. The SLD profiles indicated that the top portion of the GPS film was transformed into a thick low-density layer after conditioning, but the bottom portion showed little structural change. A previous NR study of as-prepared GPS films involving swelling with deuterated nitrobenzene showed that the central portion of the film has much lower cross-link density than the region nearest the substrate. The present data show that the central portion also swells to a much greater extent with water and hydrolyzes more rapidly. The chemical degradation mechanism was identified by IR as hydrolysis of siloxane bonds. For ATR-IR, GPS films were prepared by dip-coating, which resulted in a greater

  2. Development of ion beam figuring system with electrostatic deflection for ultraprecise X-ray reflective optics

    NASA Astrophysics Data System (ADS)

    Yamada, Jumpei; Matsuyama, Satoshi; Sano, Yasuhisa; Yamauchi, Kazuto

    2015-09-01

    We developed an ion beam figuring system that utilizes electrostatic deflection. The system can produce an arbitrary shape by deterministically scanning the ion beam. The scan of the ion beam, which can be precisely controlled using only an electrical signal, enables us to avoid degradation of the mirror shape caused by imperfect acceleration or deceleration of a mechanically scanning stage. Additionally, this surface figuring method can easily be combined with X-ray metrology because the workpiece remains fixed during the figuring. We evaluated the figuring accuracy of the system by fabricating a plano-elliptical mirror for X-ray focusing. A mirror with a shape error of 1.4 nm root mean square (RMS) with a maximum removal depth of 992 nm, which corresponds to figuring accuracy of 0.14% RMS, was achieved. After the second shape corrections, an elliptical shape with a shape error of approximately 1 nm peak-to-valley, 0.48 nm RMS could be fabricated. Then, the mirror surface was smoothed by a low-energy ion beam. Consequently, a micro-roughness of 0.117 nm RMS, measured by atomic force microscopy, was achieved over an area of 1 × 1 μm2.

  3. Development of ion beam figuring system with electrostatic deflection for ultraprecise X-ray reflective optics

    SciTech Connect

    Yamada, Jumpei; Matsuyama, Satoshi Sano, Yasuhisa; Yamauchi, Kazuto

    2015-09-15

    We developed an ion beam figuring system that utilizes electrostatic deflection. The system can produce an arbitrary shape by deterministically scanning the ion beam. The scan of the ion beam, which can be precisely controlled using only an electrical signal, enables us to avoid degradation of the mirror shape caused by imperfect acceleration or deceleration of a mechanically scanning stage. Additionally, this surface figuring method can easily be combined with X-ray metrology because the workpiece remains fixed during the figuring. We evaluated the figuring accuracy of the system by fabricating a plano-elliptical mirror for X-ray focusing. A mirror with a shape error of 1.4 nm root mean square (RMS) with a maximum removal depth of 992 nm, which corresponds to figuring accuracy of 0.14% RMS, was achieved. After the second shape corrections, an elliptical shape with a shape error of approximately 1 nm peak-to-valley, 0.48 nm RMS could be fabricated. Then, the mirror surface was smoothed by a low-energy ion beam. Consequently, a micro-roughness of 0.117 nm RMS, measured by atomic force microscopy, was achieved over an area of 1 × 1 μm{sup 2}.

  4. Interfacial Restructuring of Ionic Liquids Determined by Sum-Frequency Generation Spectroscopy and X-ray Reflectivity

    SciTech Connect

    Jeon, Yoonnam; Sung, Jaeho; Bu, Wei; Vaknin, David; Ouchi, Yukio; Kim, Doseok

    2009-01-16

    Surface sum-frequency generation spectroscopy and X-ray reflectivity were used to study the surface of [BMIM][X] ionic liquids (BMIM = 1-butyl-3-methylimidazolium cation, X = BF{sub 4}{sup -}, PF{sub 6}{sup -}, and I{sup -}). Sum-frequency signal strength from the terminal methyl groups of the cation at the surface indicates that the topmost surface of these ionic liquids is occupied by polar-oriented hydrophobic butyl chains having approximately 1/3 of the in-plane density of fully packed alkyl chains as observed by the same method for the hexadecanol Langmuir monolayer. X-ray reflectivity data reveal a layer with density larger than that of bulk. However, the reflectivity is not sufficiently sensitive to the exact location of this layer either at the vacuum interface or sandwiched between the bulk and the low-density alkyl chain, as observed in the sum-frequency measurements. Analysis of the reflectivity data in conjunction with the sum-frequency spectra strongly suggests the molecules forming the topmost layer are on average polar-oriented with their (loosely packed) butyl chains toward the gas/liquid interface, while the (densely packed) imidazolium cores/anions are in contact with the bulk liquid.

  5. X-ray Reflectivity Studies of cPLA?-C2 Domains Adsorbed onto Langmuir Monolayers of SOPC

    SciTech Connect

    Malkova,S.; Long, F.; Stahelin, R.; Pingali, S.; Murray, D.; Cho, W.; Schlossman, M.

    2005-01-01

    X-ray reflectivity is used to study the interaction of C2 domains of cytosolic phospholipase A2 (cPLA{sub 2{alpha}}-C2) with a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) supported on a buffered aqueous solution containing Ca{sup 2+}. The reflectivity is analyzed in terms of the known crystallographic structure of cPLA2{alpha}-C2 domains and a slab model representing the lipid layer to yield an electron density profile of the lipid layer and bound C2 domains. This new method of analysis determines the angular orientation and penetration depth of the cPLA{sub 2{alpha}}-C2 domains bound to the SOPC monolayer, information not available from the standard slab model analysis of x-ray reflectivity. The best-fit orientation places the protein-bound Ca{sup 2+} ions within 1 Angstrom of the lipid phosphate group (with an accuracy of {+-}3 Angstroms). Hydrophobic residues of the calcium-binding loops CBL1 and CBL3 penetrate deepest into the lipid layer, with a 2 Angstrom penetration into the tailgroup region. X-ray measurements with and without the C2 domain indicate that there is a loss of electrons in the headgroup region of the lipid monolayer upon binding of the domains. We suggest that this is due to a loss of water molecules bound to the headgroup. Control experiments with a non-calcium buffer and with domain mutants confirm that the cPLA{sub 2{alpha}}-C2 binding to the SOPC monolayer is Ca{sup 2+}-dependent and that the hydrophobic residues in the calcium-binding loops are critical for membrane binding. These results indicate that an entropic component (due to water loss) as well as electrostatic and hydrophobic interactions contributes to the binding mechanism.

  6. X-ray Reflectivity Studies of cPLA?-C2 Domains Adsorbed onto Langmuir Monolayers of SOPC

    SciTech Connect

    Raghothamachar,B.; Dudley, M.; Wang, B.; Callahan, M.; Bliss, D.; Konkapaka, P.; Wu, H.; Spencer, M.

    2005-01-01

    X-ray reflectivity is used to study the interaction of C2 domains of cytosolic phospholipase A2 (cPLA{sub 2{alpha}}-C2) with a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) supported on a buffered aqueous solution containing Ca{sup 2+}. The reflectivity is analyzed in terms of the known crystallographic structure of cPLA2{alpha}-C2 domains and a slab model representing the lipid layer to yield an electron density profile of the lipid layer and bound C2 domains. This new method of analysis determines the angular orientation and penetration depth of the cPLA{sub 2{alpha}}-C2 domains bound to the SOPC monolayer, information not available from the standard slab model analysis of x-ray reflectivity. The best-fit orientation places the protein-bound Ca{sup 2+} ions within 1 Angstrom of the lipid phosphate group (with an accuracy of {+-}3 Angstroms). Hydrophobic residues of the calcium-binding loops CBL1 and CBL3 penetrate deepest into the lipid layer, with a 2 Angstrom penetration into the tailgroup region. X-ray measurements with and without the C2 domain indicate that there is a loss of electrons in the headgroup region of the lipid monolayer upon binding of the domains. We suggest that this is due to a loss of water molecules bound to the headgroup. Control experiments with a non-calcium buffer and with domain mutants confirm that the cPLA{sub 2{alpha}}-C2 binding to the SOPC monolayer is Ca{sup 2+}-dependent and that the hydrophobic residues in the calcium-binding loops are critical for membrane binding. These results indicate that an entropic component (due to water loss) as well as electrostatic and hydrophobic interactions contributes to the binding mechanism.

  7. Impulsive solar X-ray bursts. III - Polarization, directivity, and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    NASA Technical Reports Server (NTRS)

    Langer, S. H.; Petrosian, V.

    1977-01-01

    The paper presents the spectrum, directivity, and state of polarization of the bremsstrahlung radiation expected from a beam of high-energy electrons spiraling along radial magnetic field lines toward the photosphere. A Monte Carlo method is then described for evaluation of the spectrum, directivity, and polarization of X-rays diffusely reflected from stellar photospheres. The accuracy of the technique is evaluated through comparison with analytic results. The calculated characteristics of the incident X-rays are used to evaluate the spectrum, directivity, and polarization of the reflected and total X-ray fluxes. The results are compared with observations.

  8. Impulsive solar X-ray bursts. III - Polarization, directivity, and spectrum of the reflected and total bremsstrahlung radiation from a beam of electrons directed toward the photosphere

    NASA Technical Reports Server (NTRS)

    Langer, S. H.; Petrosian, V.

    1977-01-01

    The paper presents the spectrum, directivity, and state of polarization of the bremsstrahlung radiation expected from a beam of high-energy electrons spiraling along radial magnetic field lines toward the photosphere. A Monte Carlo method is then described for evaluation of the spectrum, directivity, and polarization of X-rays diffusely reflected from stellar photospheres. The accuracy of the technique is evaluated through comparison with analytic results. The calculated characteristics of the incident X-rays are used to evaluate the spectrum, directivity, and polarization of the reflected and total X-ray fluxes. The results are compared with observations.

  9. Measurement of soft x-ray multilayer mirror reflectance at normal incidence using laser-produced plasmas

    SciTech Connect

    Trail, J.A.; Byer, R.L.; Barbee T.W. Jr.

    1988-01-25

    We have used laser-produced plasmas as a broadband source of soft x rays to measure the normal incidence reflectance of multilayer mirrors in the 10--25 nm spectral region. The measurements have a spectral resolution of 0.03 nm and a reflectance resolution of 10%. Measurements made on a Mo/Si multilayer show excellent agreement with results obtained using a synchrotron and indicate a normal incidence peak reflectance of over 50% at 15 nm. By repeating the reflectance measurement at different positions across a single 7.5 cm mirror we determined multilayer uniformity as a function of position and we relate this dependence to the geometry of the deposition process.

  10. Elemental concentrations in skin of patients with fibroeptelial polip using synchrotron radiation total reflection x-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Soares, Júlio C. A. C. R.; Anjos, Marcelino J.; Canellas, Catarine G. L.; Lopes, Ricardo T.

    2012-05-01

    In this work, the concentrations of trace elements were measured in acrochordon, a skin lesion also known as skin tag or fibroepithelial polyp, as well as in normal skin from the same patient. The samples were analyzed by Synchrotron Radiation Total Reflection X-ray Fluorescence (SRTXRF) in the Synchrotron Light National Laboratory (LNLS) in Campinas/São Paulo-Brazil. The collection of lesion and healthy skin samples, including papillary dermis and epidermis, has involved 17 patients. It was evaluated the presence of P, S, Cl, K, Ca, Fe, Cu and Zn in the paired samples, which were compared, and significant differences were found in some of them.

  11. Center for X-Ray Optics, 1992

    SciTech Connect

    Not Available

    1993-08-01

    This report discusses the following topics: Center for X-Ray Optics; Soft X-Ray Imaging wit Zone Plate Lenses; Biological X-Ray microscopy; Extreme Ultraviolet Lithography for Nanoelectronic Pattern Transfer; Multilayer Reflective Optics; EUV/Soft X-ray Reflectometer; Photoemission Microscopy with Reflective Optics; Spectroscopy with Soft X-Rays; Hard X-Ray Microprobe; Coronary Angiography; and Atomic Scattering Factors.

  12. Rb+ adsorption at the quartz(101)-aqueous interface: comparison of resonant anomalous x-ray reflectivity with ab initio calculations

    DOE PAGES

    Bellucci, Francesco; Lee, Sang Soo; Kubicki, James D.; ...

    2015-01-29

    We study adsorption of Rb+ to the quartz(101)–aqueous interface at room temperature with specular X-ray reflectivity, resonant anomalous X-ray reflectivity, and density functional theory. The interfacial water structures observed in deionized water and 10 mM RbCl solution at pH 9.8 were similar, having a first water layer at height of 1.7 ± 0.1 Å above the quartz surface and a second layer at 4.8 ± 0.1 Å and 3.9 ± 0.8 Å for the water and RbCl solutions, respectively. The adsorbed Rb+ distribution is broad and consists of presumed inner-sphere (IS) and outer-sphere (OS) complexes at heights of 1.8 ±more » 0.1 and 6.4 ± 1.0 Å, respectively. Projector-augmented planewave density functional theory (DFT) calculations of potential configurations for neutral and negatively charged quartz(101) surfaces at pH 7 and 12, respectively, reveal a water structure in agreement with experimental results. These DFT calculations also show differences in adsorbed speciation of Rb+ between these two conditions. At pH 7, the lowest energy structure shows that Rb+ adsorbs dominantly as an IS complex, whereas at pH 12 IS and OS complexes have equivalent energies. The DFT results at pH 12 are generally consistent with the two site Rb distribution observed from the X-ray data at pH 9.8, albeit with some differences that are discussed. In conclusion, surface charge estimated on the basis of the measured total Rb+ coverage was -0.11 C/m2, in good agreement with the range of the surface charge magnitudes reported in the literature.« less

  13. Quantitative resonant soft x-ray reflectivity of ultrathin anisotropic organic layers: Simulation and experiment of PTCDA on Au

    NASA Astrophysics Data System (ADS)

    Capelli, R.; Mahne, N.; Koshmak, K.; Giglia, A.; Doyle, B. P.; Mukherjee, S.; Nannarone, S.; Pasquali, L.

    2016-07-01

    Resonant soft X-ray reflectivity at the carbon K edge, with linearly polarized light, was used to derive quantitative information of film morphology, molecular arrangement, and electronic orbital anisotropies of an ultrathin 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) film on Au(111). The experimental spectra were simulated by computing the propagation of the electromagnetic field in a trilayer system (vacuum/PTCDA/Au), where the organic film was treated as an anisotropic medium. Optical constants were derived from the calculated (through density functional theory) absorption cross sections of the single molecule along the three principal molecular axes. These were used to construct the dielectric tensor of the film, assuming the molecules to be lying flat with respect to the substrate and with a herringbone arrangement parallel to the substrate plane. Resonant soft X-ray reflectivity proved to be extremely sensitive to film thickness, down to the single molecular layer. The best agreement between simulation and experiment was found for a film of 1.6 nm, with flat laying configuration of the molecules. The high sensitivity to experimental geometries in terms of beam incidence and light polarization was also clarified through simulations. The optical anisotropies of the organic film were experimentally determined and through the comparison with calculations, it was possible to relate them to the orbital symmetry of the empty electronic states.

  14. Prediction of Ba, Co and Ni for tropical soils using diffuse reflectance spectroscopy and X-ray fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Arantes Camargo, Livia; Marques Júnior, José; Reynaldo Ferracciú Alleoni, Luís; Tadeu Pereira, Gener; De Bortoli Teixeira, Daniel; Santos Rabelo de Souza Bahia, Angélica

    2017-04-01

    Environmental impact assessments may be assisted by spatial characterization of potentially toxic elements (PTEs). Diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectroscopy (XRF) are rapid, non-destructive, low-cost, prediction tools for a simultaneous characterization of different soil attributes. Although low concentrations of PTEs might preclude the observation of spectral features, their contents can be predicted using spectroscopy by exploring the existing relationship between the PTEs and soil attributes with spectral features. This study aimed to evaluate, in three geomorphic surfaces of Oxisols, the capacity for predicting PTEs (Ba, Co, and Ni) and their spatial variability by means of diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectroscopy (XRF). For that, soil samples were collected from three geomorphic surfaces and analyzed for chemical, physical, and mineralogical properties, and then analyzed in DRS (visible + near infrared - VIS+NIR and medium infrared - MIR) and XRF equipment. PTE prediction models were calibrated using partial least squares regression (PLSR). PTE spatial distribution maps were built using the values calculated by the calibrated models that reached the best accuracy using geostatistics. PTE prediction models were satisfactorily calibrated using MIR DRS for Ba, and Co (residual prediction deviation - RPD > 3.0), Vis DRS for Ni (RPD > 2.0) and FRX for all the studied PTEs (RPD > 1.8). DRS- and XRF-predicted values allowed the characterization and the understanding of spatial variability of the studied PTEs.

  15. Reflection grating spectrometer for the x-ray multi-mirror (XMM) space observatory: design and calculated performance

    SciTech Connect

    Hettrick, M.C.; Kahn, S.M.

    1985-10-01

    A spectrometer design candidate is presented for the X-ray Multi-Mirror (XMM) observatory, being planned by the European Space Agency (ESA) as a long-lived large-area of telescopes. The science requirement of moderate resolution (E/..delta..E approx.100) spectroscopy in a two octave region (0.5 to 2 keV) with extremely high throughput (effective area > 500 cm/sup 2/) results in the use of grazing incidence reflection gratings. Due to the low image quality of the telescopes (approx. 1 minute of arc), the grating dispersion must be maximized by use of the classical grating mount in which the spectrum is dispersed within the plane of incident radiation. Due to the small field of view by the x-ray telescopes, the gratings must be situated in the converging beam at the exit of the telescope. A spectrometer module consists of a thin-foil conical mirror telescope, a stack of plane varied-space reflection gratings and an imaging proportional counter. This system is analyzed on the basis of dispersion, geometric aberrations and efficiency. At a spectral resolution of 0.15 A, a twenty module XMM would attain an average effective area of approx.900 cm/sup 2/, reaching twice this value at the peak wavelength (15 A). Similar throughput is obtained in second order centered at 7.5 A, the two spectral orders separated by the non-dispersive energy resolution of the proportional counter. Continuous spectra are obtained in the 6-25 A band (0.5 to 2 keV), and can be extended to 45 A if desired by tuning of the grating. The instrument sensitivity is sufficient to allow the first spectral detection of soft x-ray features in external galaxies, with access to an estimated population of several hundred active galactic nuclei. Such observations will expand vastly the roles feasible for spectroscopy in x-ray astrophysics, marking the beginning of a new era in space astronomy.

  16. Production of spectrally narrow soft-x-ray radiation through the use of broadband laser-produced plasma sources and multilayer-coated reflecting optics.

    PubMed

    Eligon, A M; Gruber, N; Silfvast, W T

    1995-08-01

    We describe a special filter design that produces spectrally narrow soft-x-ray radiation by using a broadband laser-produced plasma source and multilayer-coated reflecting optics. Calculations for the design were carried out at several laser-produced plasma-source temperatures and various multilayermirror combinations with and without a soft-x-ray filter. We determined that the best arrangement for a laser-produced plasma source consists of two multilayer mirrors and one soft-x-ray filter for each temperature investigated.

  17. Total reflection X-ray fluorescence analysis of trace-elements in candies marketed in Mexico

    NASA Astrophysics Data System (ADS)

    Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

    2010-06-01

    Trace metals concentrations in food are significant for nutrition, due either to their nature or toxicity. Sweets, including chewing gum and candies, are not exactly a food, but they usually are unwearied consumed by children, the most vulnerable age-group to any kind of metal contamination in the food chain. The presence of relatively high concentrations of heavy metals such as Lead elicits concern since children are highly susceptible to heavy metals poisoning. Trace-metals concentrations were determined for six different flavors of a Mexican candy by means of Total X-ray Fluorescence Spectrometry. Triplicate samples of the various candy's flavours (strawberry, pineapple, lemon, blackberry, orange and chilli) were digested in 8 mL of a mix of supra-pure HNO 3 and H 2O 2 (6 mL: 2 mL) in a microwave oven MARS-X. Results show the presence of essential and toxic elements such as Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Pb. All metal concentrations were higher and significantly different ( α = 0.05) in chilli candy, compared to other candy flavours. Lead concentration fluctuated in the range of 0.102 to 0.342 μg g - 1 . A discussion about risk consumption and concentration allowed by Mexican and International Norms is made. As a part of the Quality Control Program, a NIST standard of "Citrus Leaves" and a blank were treated in the same way.

  18. Wavelength-dispersive total-reflection X-ray fluorescence with an efficient Johansson spectrometer and an undulator X-ray source: detection of 10-16 g-level trace metals.

    PubMed

    Sakurai, Kenji; Eba, Hiromi; Inoue, Katsuaki; Yagi, Naoto

    2002-09-01

    The present paper reports significant enhancement of the detection power for total-reflection X-ray fluorescence (TXRF). The employment of an efficient wavelength-dispersive spectrometer rather than a conventional Si(Li) detector, as well as the use of a quasi-monochromatic undulator X-ray source, completely changed the quality of X-ray florescence spectra. The energy resolution is 20 times better, which effectively contributes to reducing the low-energy tail of the scattering background and to separating neighboring X-ray florescence peaks. Another advantage is its capability with respect to high-counting-rate measurements, which ensure the detection of weak signals from trace materials. The absolute and relative detection limit for nickel are 3.1 x 10(-16) g and 3.1 ppt (pg/g) for a 0.1-microL droplet of pure water, respectively, which is nearly 50 times better than the current best data achieved by conventional energy-dispersive TXRF using a Si(Li) detector system.

  19. Neutron and X-ray reflectivity studies on DNA adsorption on mixed DPPC/DC-Cholesterol monolayers

    NASA Astrophysics Data System (ADS)

    Wu, Jui-Ching; Lin, Tsang-Lang; Jeng, U.-Ser; Lee, Hsin-Yi; Gutberlet, Thomas

    2006-11-01

    We have studied DNA adsorption on mixed DPPC/DC-Chol monolayers. Solid supported mixed monolayers on silicon wafers were prepared using Langmuir-Blodgett (LB) dipping technique. Neutron and X-ray reflectivity measurements were used to characterize these LB monofilms. For LB monofilms with DNA adsorption, the reflectivity data of the DPPC/DNA film are very close to that from the DPPC film, which indicates only minor DNA adsorption on the pure DPPC monolayer. Increasing the percentage of DC-Chol, film thickness increases. The DC-Chol/DNA film is thicker than the pure DC-Chol film (film thickness 18 Å) by about 9 Å due to the presence of adsorbed DNA. A model is presented to explain the structure of the lipid/DNA film.

  20. Elemental depth profiling in transparent conducting oxide thin film by X-ray reflectivity and grazing incidence X-ray fluorescence combined analysis

    NASA Astrophysics Data System (ADS)

    Rotella, H.; Caby, B.; Ménesguen, Y.; Mazel, Y.; Valla, A.; Ingerle, D.; Detlefs, B.; Lépy, M.-C.; Novikova, A.; Rodriguez, G.; Streli, C.; Nolot, E.

    2017-09-01

    The optical and electrical properties of transparent conducting oxide (TCO) thin films are strongly linked with the structural and chemical properties such as elemental depth profile. In R&D environments, the development of non-destructive characterization techniques to probe the composition over the depth of deposited films is thus necessary. The combination of Grazing-Incidence X-ray Fluorescence (GIXRF) and X-ray reflectometry (XRR) is emerging as a fab-compatible solution for the measurement of thickness, density and elemental profile in complex stacks. Based on the same formalism, both techniques can be implemented on the same experimental set-up and the analysis can be combined in a single software in order to refine the sample model. While XRR is sensitive to the electronic density profile, GIXRF is sensitive to the atomic density (i. e. the elemental depth profile). The combination of both techniques allows to get simultaneous information about structural properties (thickness and roughness) as well as the chemical properties. In this study, we performed a XRR-GIXRF combined analysis on indium-free TCO thin films (Ga doped ZnO compound) in order to correlate the optical properties of the films with the elemental distribution of Ga dopant over the thickness. The variation of optical properties due to annealing process were probed by spectroscopic ellipsometry measurements. We studied the evolution of atomic profiles before and after annealing process. We show that the blue shift of the band gap in the optical absorption edge is linked to a homogenization of the atomic profiles of Ga and Zn over the layer after the annealing. This work demonstrates that the combination of the techniques gives insight into the material composition and makes the XRR-GIXRF combined analysis a promising technique for elemental depth profiling.

  1. Analytical performance of benchtop total reflection X-ray fluorescence instrumentation for multielemental analysis of wine samples

    NASA Astrophysics Data System (ADS)

    Dalipi, Rogerta; Marguí, Eva; Borgese, Laura; Bilo, Fabjola; Depero, Laura E.

    2016-06-01

    Recent technological improvements have led to a widespread adoption of benchtop total reflection X-ray fluorescence systems (TXRF) for analysis of liquid samples. However, benchtop TXRF systems usually present limited sensitivity compared with high-scale instrumentation which can restrict its application in some fields. The aim of the present work was to evaluate and compare the analytical capabilities of two TXRF systems, equipped with low power Mo and W target X-ray tubes, for multielemental analysis of wine samples. Using the Mo-TXRF system, the detection limits for most elements were one order of magnitude lower than those attained using the W-TXRF system. For the detection of high Z elements like Cd and Ag, however, W-TXRF remains a very good option due to the possibility of K-Lines detection. Accuracy and precision of the obtained results have been evaluated analyzing spiked real wine samples and comparing the TXRF results with those obtained by inductively coupled plasma emission spectroscopy (ICP-OES). In general, good agreement was obtained between ICP-OES and TXRF results for the analysis of both red and white wine samples except for light elements (i.e., K) which TXRF concentrations were underestimated. However, a further achievement of analytical quality of TXRF results can be achieved if wine analysis is performed after dilution of the sample with de-ionized water.

  2. Hard x-ray spectroscopy and imaging by a reflection zone plate in the presence of astigmatism

    DOE PAGES

    Braig, Christoph; Lochel, Heike; Firsov, Alexander; ...

    2015-12-17

    Here, the feasibility of an off-axis x-ray reflection zone plate to perform wavelength-dispersive spectroscopy, on-axis point focusing, and two-dimensional imaging is demonstrated by means of one and the same diffractive optical element (DOE) at a synchrotron radiation facility. The resolving power varies between 3 × 101 and 4 × 102 in the range of 7.6 keV to 9.0 keV, with its maximum at the design energy of 8.3 keV. This result is verified using an adjustable entrance slit, by which horizontal (H) and vertical (V) focusing to 0.85 μm(H) and 1.29 μm(V) is obtained near the sagittal focal plane ofmore » the astigmatic configuration. An angular and axial scan proves an accessible field of view of at least 0.6 arcmin × 0.8 arcmin and a focal depth of ±0.86 mm. Supported by the grating efficiency of around 17.5% and a very short pulse elongation, future precision x-ray fluorescence and absorption studies of transition metals at their K-edge on an ultrashort timescale could benefit from our findings.« less

  3. Hard x-ray spectroscopy and imaging by a reflection zone plate in the presence of astigmatism

    SciTech Connect

    Braig, Christoph; Lochel, Heike; Firsov, Alexander; Brzhezinskaya, Maria; Hafner, Aljosa; Rehanek, Jens; Wojcik, Michael; Macrander, Albert; Assoufid, Lahsen; Erko, Alexei

    2015-12-17

    Here, the feasibility of an off-axis x-ray reflection zone plate to perform wavelength-dispersive spectroscopy, on-axis point focusing, and two-dimensional imaging is demonstrated by means of one and the same diffractive optical element (DOE) at a synchrotron radiation facility. The resolving power varies between 3 × 101 and 4 × 102 in the range of 7.6 keV to 9.0 keV, with its maximum at the design energy of 8.3 keV. This result is verified using an adjustable entrance slit, by which horizontal (H) and vertical (V) focusing to 0.85 μm(H) and 1.29 μm(V) is obtained near the sagittal focal plane of the astigmatic configuration. An angular and axial scan proves an accessible field of view of at least 0.6 arcmin × 0.8 arcmin and a focal depth of ±0.86 mm. Supported by the grating efficiency of around 17.5% and a very short pulse elongation, future precision x-ray fluorescence and absorption studies of transition metals at their K-edge on an ultrashort timescale could benefit from our findings.

  4. X-ray magnetic circular dichroism and reflection anisotropy spectroscopy Kerr effect studies of capped magnetic nanowires

    SciTech Connect

    Cunniffe, J. P.; McNally, D.E.; Liberati, M.; Arenholz, E.; McGuinness, C.; McGilp, J. F.

    2010-03-02

    Aligned Co wires grown on Pt(997) under ultra-high vacuum conditions have been capped successfully by the epitaxial growth of Au monolayers (ML) at room temperature. The samples were kept under vacuum except when transferring between apparatus or when making some of the measurements. No degradation of the Co wires was detected during the measurements. The magneto-optic response of the system was measured using X-ray magnetic circular dichroism (XMCD) at the Co L{sub 2,3} edge and reflection anisotropy spectroscopy (RAS) at near normal incidence, which is sensitive to the normal component of the out-of-plane magnetization via the Kerr effect (MOKE). Capping the wires significantly impacts their magnetic properties. Comparison of the magneto-optic response of the system at X-ray and optical energies reveals small differences that are attributed to the induced moment in the Pt substrate and Au capping layer not picked up by the element specific XMCD measurements. The sensitivity of RAS-MOKE is sufficient to allow the determination of the easy axis direction of the capped wires to within a few degrees. The results for a 6-atom-wide Co wire sample, capped with 6 ML of Au, are consistent with the capped wires possessing perpendicular magnetization.

  5. Development and production of a multilayer-coated x-ray reflecting stack for the Athena mission

    NASA Astrophysics Data System (ADS)

    Massahi, S.; Ferreira, D. D. M.; Christensen, F. E.; Shortt, B.; Girou, D. A.; Collon, M.; Landgraf, B.; Barriere, N.; Krumrey, M.; Cibik, L.; Schreiber, S.

    2016-07-01

    The Advanced Telescope for High-Energy Astrophysics, Athena, selected as the European Space Agency's second large-mission, is based on the novel Silicon Pore Optics X-ray mirror technology. DTU Space has been working for several years on the development of multilayer coatings on the Silicon Pore Optics in an effort to optimize the throughput of the Athena optics. A linearly graded Ir/B4C multilayer has been deposited on the mirrors, via the direct current magnetron sputtering technique, at DTU Space. This specific multilayer, has through simulations, been demonstrated to produce the highest reflectivity at 6 keV, which is a goal for the scientific objectives of the mission. A critical aspect of the coating process concerns the use of photolithography techniques upon which we will present the most recent developments in particular related to the cleanliness of the plates. Experiments regarding the lift-off and stacking of the mirrors have been performed and the results obtained will be presented. Furthermore, characterization of the deposited thin-films was performed with X-ray reflectometry at DTU Space and in the laboratory of the Physikalisch-Technische Bundesanstalt at the synchrotron radiation facility BESSY II.

  6. High Resolution X-Ray Spectroscopy of zeta Puppis with the XMM-Newton Reflection Grating Spectrometer

    NASA Technical Reports Server (NTRS)

    Kahn, S. M.; Leutenegger, M. A.; Cottam, J.; Rauw, G.; Vreux, J.-M.; denBoggende, A. J. F.; Mewe, R.; Guedel, M.

    2000-01-01

    We present the first high resolution X-ray spectrum of the bright O4Ief supergiant star Puppis, obtained with the Reflection Grating Spectrometer on- board XMM-Newton. The spectrum exhibits bright emission lines of hydrogen-like and helium-like ions of nitrogen, oxygen, neon, magnesium, and silicon, as well as neon-like ions of iron. The lines are all significantly resolved, with characteristic velocity widths of order 1000 - 1500 km/ s. The nitrogen lines are especially strong, and indicate that the shocked gas in the wind is mixed with CNO-burned material, as has been previously inferred for the atmosphere of this star from ultraviolet spectra. We find that the forbidden to intercombination line ratios within the helium-like triplets are anomalously low for N VI, O VII, and Ne IX. While this is sometimes indicative of high electron density, we show that in this case, it is instead caused by the intense ultraviolet radiation field of the star. We use this interpretation to derive constraints on the location of the X-ray emitting shocks within the wind that agree remarkably well with current theoretical models for this system.

  7. Interfacial Width Measurements of Dielectric/P(NDI2OD-T2) Using Resonant Soft X-ray Reflectivity

    NASA Astrophysics Data System (ADS)

    Yan, Hongping; Gu, Ziran; Gann, Eliot; Collins, Brian; Swaraj, Sufal; Wang, Cheng; Schuettfort, Torben; McNeill, Chris; Ade, Harald

    2011-03-01

    Interfaces between a conjugated polymer and a dielectric play a critical role in organic thin-film transistors, yet it's difficult to measure. Resonant Soft X-ray Reflectivity (R-SoXR) is a unique and relatively simple method to investigate such interfaces. By tuning the soft X-ray energies, we are able to selectively and quantitatively characterize the interfacial width and thicknesses of the films. In an effort to relate performance to interface structure, we have used R-SoXR to investigate polystyrene (PS) or poly(methyl methacrylate) (PMMA) as the top layer and poly{[N,N9-bis(2-octyldodecyl)-naphtha-lene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5, 59-(2,29-bithiophene)} (P(NDI2OD-T2)) as bottom layer supported on a Si substrate. We found that the device with PS as dielectric has a higher threshold voltage, which correlates to the increased interfacial trapping due to increased interfacial roughness. The extension of R-SoXR to the energy of fluorine K absorption edge is also demonstrated. NSF DMR-0906457, DOE DE-FG02-98ER45737.

  8. Anisotropic illumination in AGNs. The reflected component. Comparison to hard X-ray spectra from Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Malzac, J.; Jourdain, E.; Petrucci, P. O.; Henri, G.

    1998-08-01

    We calculate the reflection component predicted by the anisotropic illumination model of Henri & Petrucci \\cite{henri}. This component appears to be more important than for isotropic models. The overall X/gamma spectrum is found to be strongly angle-dependent. When the accretion disc is seen with a nearly edge-on orientation the reflection hump is weak, while a face-on viewing angle leads to a proeminent reflection hump with an equivalent reflection coefficient R ~ 50. Such reflection dominated Seyfert 1s galaxies are not observed. By fitting observed X/gamma spectra, we derive inclination angle theta ~ 70degr for MCG 8-11-11 and theta ~ 80degr for IC 4329a and NGC 4151. Although the model succeed in reproducing individual observed spectra, it requires all the Seyfert 1s observed in the X-ray band to be seen with large inclination angles. Such a situation is highly improbable. On the other hand, we show that the ionisation of a fair part of the reflecting disk could represent an interesting improvement of the model, consistent with the data and relaxing the constraints on the high energy cut-off in Seyfert galaxies.

  9. X-RAYING AN ACCRETION DISK IN REALTIME: THE EVOLUTION OF IONIZED REFLECTION DURING A SUPERBURST FROM 4U 1636-536

    SciTech Connect

    Keek, L.; Ballantyne, D. R.; Kuulkers, E.; Strohmayer, T. E.

    2014-12-20

    When a thermonuclear X-ray burst ignites on an accreting neutron star, the accretion disk undergoes sudden strong X-ray illumination, which can drive a range of processes in the disk. Observations of superbursts, with durations of several hours, provide the best opportunity to study these processes and to probe accretion physics. Using detailed models of X-ray reflection, we perform time resolved spectroscopy of the superburst observed from 4U 1636-536 in 2001 with the Rossi X-Ray Timing Explorer. The spectra are consistent with a blackbody reflecting off a photoionized accretion disk, with the ionization state dropping with time. The evolution of the reflection fraction indicates that the initial reflection occurs from a part of the disk at larger radius, subsequently transitioning to reflection from an inner region of the disk. Even though this superburst did not reach the Eddington limit, we find that a strong local absorber develops during the superburst. Including this event, only two superbursts have been observed by an instrument with sufficient collecting area to allow for this analysis. It highlights the exciting opportunity for future X-ray observatories to investigate the processes in accretion disks when illuminated by superbursts.

  10. α-Synuclein insertion into supported lipid bilayers as seen by in situ X-ray reflectivity.

    PubMed

    Hähl, Hendrik; Möller, Isabelle; Kiesel, Irena; Campioni, Silvia; Riek, Roland; Verdes, Dorinel; Seeger, Stefan

    2015-03-18

    Large aggregates of misfolded α-synuclein inside neuronal cells are the hallmarks of Parkinson's disease. The protein's natural function and its supposed toxicity, however, are believed to be closely related to its interaction with cell and vesicle membranes. Upon this interaction, the protein folds into an α-helical structure and intercalates into the membrane. In this study, we focus on the changes in the lipid bilayer caused by this intrusion. In situ X-ray reflectivity was applied to determine the vertical density structure of the bilayer before and after exposure to α-synuclein. It was found that the α-synuclein insertion, wild type and E57K variant, caused a reduction in bilayer thickness. This effect may be one factor in the membrane pore formation ability of α-synuclein.

  11. Determination of copper, iron and zinc in spirituous beverages by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Capote, T.; Marcó, L. M.; Alvarado, J.; Greaves, E. D.

    1999-10-01

    The concentration of copper in traditional homemade alcoholic distillates produced in Venezuela (Cocuy de Penca) were determined by total reflection X-ray fluorescence (TXRF) using vanadium as internal standard. The results were compared to those obtained by flame atomic absorption spectrometry (FAAS). Three preparative methods of addition of vanadium were compared: classical internal standard addition, 'layer on layer' internal standard addition and in situ addition of internal standard. The TXRF procedures were accurate and the precision was comparable to that obtained by the FAAS technique. Copper levels were above the maximum allowed limits for similar beverages. Zinc and iron in commercial and homemade distilled beverages were also analyzed by TXRF with in situ addition of internal standard demonstrating the usefulness of this technique for trace metal determination in distillates.

  12. X-ray view of four high-luminosity Swift/BAT AGN: Unveiling obscuration and reflection with Suzaku

    NASA Astrophysics Data System (ADS)

    Fioretti, V.; Angelini, L.; Mushotzky, R. F.; Koss, M.; Malaguti, G.

    2013-07-01

    Aims: A complete census of obscured active galactic nuclei (AGN) is necessary to reveal the history of the super massive black hole (SMBH) growth and galaxy evolution in the Universe given the complex feedback processes and the fact that much of this growth occurs in an obscured phase. In this context, hard X-ray surveys and dedicated follow-up observations represent a unique tool for selecting highly absorbed AGN and for characterizing the obscuring matter surrounding the SMBH. Here we focus on the absorption and reflection occurring in highly luminous, quasar-like AGN, to study the relation between the geometry of the absorbing matter and the AGN nature (e.g. X-ray, optical, and radio properties), and to help to determine the column density dependency on the AGN luminosity. Methods: The Swift/BAT nine-month survey observed 153 AGN, all with ultra-hard X-ray BAT fluxes in excess of 10-11 erg cm-2 s-1 and an average redshift of 0.03. Among them, four of the most luminous BAT AGN (44.73 < Log LBAT < 45.31) were selected as targets of Suzaku follow-up observations: J2246.0+3941 (3C 452), J0407.4+0339 (3C 105), J0318.7+6828, and J0918.5+0425. The column density, scattered/reflected emission, the properties of the Fe K line, and a possible variability are fully analyzed. For the latter, the spectral properties from Chandra, XMM-Newton and Swift/XRT public observations were compared with the present Suzaku analysis, adding an original spectral analysis when none was available from the literature. Results: Of our sample, 3C 452 is the only certain Compton-thick AGN candidate because of i) the high absorption (NH ~ 4 × 1023 cm-2) and strong Compton reflection; ii) the lack of variability; iii) the "buried" nature, i.e. the low scattering fraction (<0.5%) and the extremely low relative [OIII] luminosity. In contrast 3C 105 is not reflection-dominated, despite the comparable column density, X-ray luminosity and radio morphology, but shows a strong long-term variability in

  13. X-ray View of Four High-Luminosity Swift-BAT AGN: Unveiling Obscuration and Reflection with Suzaku

    NASA Technical Reports Server (NTRS)

    Fiorettil, V.; Angelini, L.; Mushotzky, R. F.; Koss, M.; Malaguti, G.

    2013-01-01

    Aims. A complete census of obscured Active Galactic Nuclei (AGN) is necessary to reveal the history of the super massive black hole (SMBH) growth and galaxy evolution in the Universe given the complex feedback processes and the fact that much of this growth occurs in an obscured phase. In this context, hard X-ray surveys and dedicated follow-up observations represent a unique tool for selecting highly absorbed AGN and for characterizing the obscuring matter surrounding the SMBH. Here we focus on the absorption and reflection occurring in highly luminous, quasar-like AGN, to study the relation between the geometry of the absorbing matter and the AGN nature (e.g. X-ray, optical, and radio properties), and to help to determine the column density dependency on the AGN luminosity. Methods. The Swift/BAT nine-month survey observed 153 AGN, all with ultra-hard X-ray BAT fluxes in excess of 10(exp -11) erg per square centimeter and an average redshift of 0.03. Among them, four of the most luminous BAT AGN (44.73 less than LogLBAT less than 45.31) were selected as targets of Suzaku follow-up observations: J2246.0+3941 (3C 452), J0407.4+0339 (3C 105), J0318.7+6828, and J0918.5+0425. The column density, scattered/reflected emission, the properties of the Fe K line, and a possible variability are fully analyzed. For the latter, the spectral properties from Chandra, XMM-Newton and Swift/XRT public observations were compared with the present Suzaku analysis, adding an original spectral analysis when non was available from the literature. Results. Of our sample, 3C 452 is the only certain Compton-thick AGN candidate because of i) the high absorption (N(sub H) approximately 4 × 10(exp 23) per square centimeter) and strong Compton reflection; ii) the lack of variability; iii) the "buried" nature, i.e. the low scattering fraction (less than 0.5%) and the extremely low relative [OIII] luminosity. In contrast 3C 105 is not reflection-dominated, despite the comparable column density

  14. Practical guidelines for best practice on Total Reflection X-ray Fluorescence spectroscopy: Analysis of aqueous solutions

    NASA Astrophysics Data System (ADS)

    Riaño, Sofía; Regadío, Mercedes; Binnemans, Koen; Vander Hoogerstraete, Tom

    2016-10-01

    Despite the fact that Total Reflection X-ray Fluorescence (TXRF) is becoming more and more popular as a quantification technique in analytical chemistry due to its simplicity and robustness, there are still some key aspects related to the sample preparation that need to be improved. In this work, the effect of different parameters is investigated: measurement time, carrier position, sample volume and sample drying time. The measurement time and the sample volume on the carriers mainly affect the recovery rate and relative standard deviation of the quantified metal from aqueous solutions. The most important parameters that play a fundamental role in the calibration of a TXRF machine such as choice of the standard element and concentration ratio between the analyte and the standard are discussed. Practical and easy guidelines for the correct preparation of aqueous samples are presented. These can be used by both less and more experienced TXRF users, interested in measuring metal ion concentrations in aqueous samples.

  15. X-ray and neutron reflectivity study of solid-supported lipid membranes prepared by spin coating

    SciTech Connect

    Generosi, Johanna; Castellano, Carlo; Pozzi, Daniela; Castellano, Agostina Congiu; Felici, Roberto; Natali, Francesca; Fragneto, Giovanna

    2004-12-01

    We present a study of x-ray synchrotron radiation and neutron reflectivity on solid-supported lipid membranes prepared by spin coating. This technique has the advantage of allowing the control of the number of lipid layers by varying the deposition parameters. The experiments were performed on the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane chloride salt (DOTAP), the neutral lipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), the lipid mixture (DOTAP-DOPC), and the complex (DOTAP-DOPC/DNA) deposited on wafers. Only single neutral lipids or lipid-peptide mixtures were deposited on solid substrate using the spin coating technique and characterized. Results on the structure of the deposited lipid layers indicate that DNA contributes to the order in the lipoplexes.

  16. Barrier performance optimization of atomic layer deposited diffusion barriers for organic light emitting diodes using x-ray reflectivity investigations

    SciTech Connect

    Singh, Aarti Schröder, Uwe; Klumbies, Hannes; Müller-Meskamp, Lars; Leo, Karl; Geidel, Marion; Knaut, Martin; Hoßbach, Christoph; Albert, Matthias; Mikolajick, Thomas

    2013-12-02

    The importance of O{sub 3} pulse duration for encapsulation of organic light emitting diodes (OLEDs) with ultra thin inorganic atomic layer deposited Al{sub 2}O{sub 3} layers is demonstrated for deposition temperatures of 50 °C. X-ray reflectivity (XRR) measurements show that O{sub 3} pulse durations longer than 15 s produce dense and thin Al{sub 2}O{sub 3} layers. Correspondingly, black spot growth is not observed in OLEDs encapsulated with such layers during 91 days of aging under ambient conditions. This implies that XRR can be used as a tool for process optimization of OLED encapsulation layers leading to devices with long lifetimes.

  17. Diffusion of Ag into organic semiconducting materials: a combined analytical study using transmission electron microscopy and X-ray reflectivity.

    PubMed

    Fladischer, Stefanie; Neuhold, Alfred; Kraker, Elke; Haber, Thomas; Lamprecht, Bernhard; Salzmann, Ingo; Resel, Roland; Grogger, Werner

    2012-10-24

    This study shows that the morphology of organic/metal interfaces strongly depends on process parameters and the involved materials. The interface between organic n-type blocking layer materials and the top Ag cathode within an organic photodiode was investigated. Ag was deposited on either amorphous tris-8-hydroxyquinolinato-aluminum (Alq(3)) or crystalline 4,7-diphenyl-1,10-phenanthroline (Bphen) using different deposition techniques such as electron beam deposition, ion beam sputtering, and vacuum thermal evaporation at various deposition rates. The interfaces were studied by transmission electron microscopy and X-ray reflectivity. It was found that Bphen does not show any Ag diffusion no matter which deposition technique was used, whereas the Ag diffusion into Alq(3) depends on the deposition technique and the deposition rate. The highest amount of Ag diffusion into Alq(3) occurred by using thermal vacuum deposition at low deposition rates.

  18. Use of total-reflection X-ray fluorescence in search of a biomonitor for environmental pollution in Vietnam

    NASA Astrophysics Data System (ADS)

    Brauer, Hans; Wagner, Annemarie; Boman, Johan; Viet Binh, Doan

    2001-11-01

    The concentration of trace elements in tissues of several animals collected in the Ha Nam province, approximately 40 km south of Hanoi, Vietnam, has been investigated using total-reflection X-ray fluorescence analysis. We find that the freshwater mussel is probably the optimal choice of biomonitor for the pollution situation in Vietnam, but the freshwater crab, the toad and the catfish are also good candidates. The krait is probably also well suited for this purpose. It is shown that since several elements show a more or less pronounced accumulation tendency in a particular tissue it can be of great use to determine the levels in different tissues. When selecting an organism to be used as a biomonitor, other factors besides the mere concentration of trace elements must be considered, for instance the abundance and feeding habits.

  19. Diffraction efficiency of a replicated, flight-like off-plane reflection grating baselined for future X-ray missions

    NASA Astrophysics Data System (ADS)

    Miles, Drew; McEntaffer, Randall; McCoy, Jake; Tutt, James; DeRoo, Casey

    2017-01-01

    Future soft X-ray spectroscopy missions have science requirements that demand higher instrument throughput and higher resolution than currently available technology. A key element in such spectrometers are dispersive elements such as diffraction gratings. Our group at Penn State University develops and fabricates off-plane reflection gratings in an effort to achieve the level of performance required by future missions. We present here efficiency measurements made in the 0.3 - 1.5 keV energy band at the Advanced Light Source (ALS) synchrotron at Lawrence Berkley National Laboratory for one such grating, which was replicated using UV-nanoimprint techniques from a grating master fabricated using electron-beam lithography, plasma etching, and potassium hydroxide etching. These results represent the first successful demonstration of off-plane grating replicas produced via these fabrication techniques and provide baseline efficiency measurements for flight-like replicated gratings.

  20. Total reflection x-ray fluorescence spectroscopy as a tool for evaluation of iron concentration in ferrofluids and yeast samples

    NASA Astrophysics Data System (ADS)

    Kulesh, N. A.; Novoselova, I. P.; Safronov, A. P.; Beketov, I. V.; Samatov, O. M.; Kurlyandskaya, G. V.; Morozova, M.; Denisova, T. P.

    2016-10-01

    In this study, total reflection x-ray fluorescent (TXRF) spectrometry was applied for the evaluation of iron concentration in ferrofluids and biological samples containing iron oxide magnetic nanoparticles obtained by the laser target evaporation technique. Suspensions of maghemite nanoparticles of different concentrations were used to estimate the limitation of the method for the evaluation of nanoparticle concentration in the range of 1-5000 ppm in absence of organic matrix. Samples of single-cell yeasts grown in the nutrient media containing maghemite nanoparticles were used to study the nanoparticle absorption mechanism. The obtained results were analyzed in terms of applicability of TXRF for quantitative analysis in a wide range of iron oxide nanoparticle concentrations for biological samples and ferrofluids with a simple established protocol of specimen preparation.

  1. X-ray reflection efficiency of nickel-coated quartz optical flats

    NASA Technical Reports Server (NTRS)

    Reynolds, J. M.; Fields, S. A.; Wilson, R. M.

    1973-01-01

    The reflection efficiency of quartz optical flats vacuum coated with 1000-A nickel was evaluated. Of the three vacuum coated samples tested, two had been contaminated during the firing of the Lunar Module Reaction Control System in the vacuum chamber. Measurements were made for 1.54-, 1.79-, and 2.29-A incident radiation. The reflection efficiency of the contaminated samples was reduced by as much as 50 percent for some angles of incidence.

  2. JGIXA - A software package for the calculation and fitting of grazing incidence X-ray fluorescence and X-ray reflectivity data for the characterization of nanometer-layers and ultra-shallow-implants

    NASA Astrophysics Data System (ADS)

    Ingerle, D.; Pepponi, G.; Meirer, F.; Wobrauschek, P.; Streli, C.

    2016-04-01

    Grazing incidence XRF (GIXRF) is a very surface sensitive, nondestructive analytical tool making use of the phenomenon of total external reflection of X-rays on smooth polished surfaces. In recent years the method experienced a revival, being a powerful tool for process analysis and control in the fabrication of semiconductor based devices. Due to the downscaling of the process size for semiconductor devices, junction depths as well as layer thicknesses are reduced to a few nanometers, i.e. the length scale where GIXRF is highly sensitive. GIXRF measures the X-ray fluorescence induced by an X-ray beam incident under varying grazing angles and results in angle dependent intensity curves. These curves are correlated to the layer thickness, depth distribution and mass density of the elements in the sample. But the evaluation of these measurements is ambiguous with regard to the exact distribution function for the implants as well as for the thickness and density of nanometer-thin layers. In order to overcome this ambiguity, GIXRF can be combined with X-ray reflectometry (XRR). This is straightforward, as both techniques use similar measurement procedures and the same fundamental physical principles can be used for a combined data evaluation strategy. Such a combined analysis removes ambiguities in the determined physical properties of the studied sample and, being a correlative spectroscopic method, also significantly reduces experimental uncertainties of the individual techniques. In this paper we report our approach to a correlative data analysis, based on a concurrent calculation and fitting of simultaneously recorded GIXRF and XRR data. Based on this approach we developed JGIXA (Java Grazing Incidence X-ray Analysis), a multi-platform software package equipped with a user-friendly graphic user interface (GUI) and offering various optimization algorithms. Software and data evaluation approach were benchmarked by characterizing metal and metal oxide layers on

  3. An examination of black hole binaries using X-ray observations and the development of the Bragg reflection polarimeter

    NASA Astrophysics Data System (ADS)

    Allured, Ryan

    Black hole binaries (BHBs) consist of a black hole which accretes matter from a companion star and emits radiation primarily in the X-ray band. They are known to evolve through various states of emission, which are believed to signify changes in the accretion geometry. MAXI J1659--152 is a recently discovered galactic BHB, and we used Rossi X-ray Timing Explorer (RXTE) observations to investigate its state evolution during its 2010 outburst. This evolution was found to be similar to that of other known BHBs, although its thermal spectral component was relatively weak. The data was also used to estimate the black hole mass to be 3.6--8.0 solar masses. Archival RXTE and Swift data were used to examine another BHB known as GX 339--4 in its faint, hard emission state. This source has a persistent iron line in its spectrum throughout its various emission states, and it is frequently used to estimate the inner radius of its accretion disk. The data were unable to constrain the inner radius through the modeling of the iron line, but estimates based on modeling of the thermal spectral component proved to be consistent with an increase in inner radius at low luminosities. Theoretical predictions of the soft X-ray polarization of BHBs indicate a change in both angle and magnitude with energy. The details of this change depend on both the spin and mass of the black hole. The NASA Gravity and Extreme Magnetism Small Explorer (GEMS) mission sought to use this effect to measure the spin of BHBs, which is necessary to develop tests of the Kerr metric in general relativity. The Bragg Reflection Polarimeter (BRP) was the student experiment on this mission, and was in the beginning stages of flight fabrication at the time of the mission's cancellation in May 2012. A prototype multilayer reflector meeting nearly all requirements was developed and its performance measured at a synchrotron beamline. Monte-Carlo simulations were carried out to estimate the ultimate polarization

  4. Analysis of low Z elements in various environmental samples with total reflection X-ray fluorescence (TXRF) spectrometry

    NASA Astrophysics Data System (ADS)

    Hoefler, H.; Streli, C.; Wobrauschek, P.; Óvári, M.; Záray, Gy.

    2006-11-01

    Recently there is a growing interest in low Z elements such as carbon, oxygen up to sulphur and phosphorus in biological specimen. Total reflection X-ray fluorescence (TXRF) spectrometry is a suitable technique demanding only very small amounts of sample. On the other side, the detection of low Z elements is a critical point of this analytical technique. Besides other effects, self absorption may occur in the samples, because of the low energy of the fluorescence radiation. The calibration curves might be not linear any longer. To investigate this issue water samples and samples from human cerebrospinal fluid were used to examine absorption effects. The linearity of calibration curves in dependence of sample mass was investigated to verify the validity of the thin film approximation. The special requirements to the experimental setup for low Z energy dispersive fluorescence analysis were met by using the Atominstitute's TXRF vacuum chamber. This spectrometer is equipped with a Cr-anode X-ray tube, a multilayer monochromator and a SiLi detector with 30 mm 2 active area and with an ultrathin entrance window. Other object on this study are biofilms, living on all subaqueous surfaces, consisting of bacteria, algae and fungi embedded in their extracellular polymeric substances (EPS). Many trace elements from the water are bound in the biofilm. Thus, the biofilm is a useful indicator for polluting elements. For biomonitoring purposes not only the polluting elements but also the formation and growth rate of the biofilm are important. Biofilms were directly grown on TXRF reflectors. Their major elements and C-masses correlated to the cultivation time were investigated. These measured masses were related to the area seen by the detector, which was experimentally determined. Homogeneity of the biofilms was checked by measuring various sample positions on the reflectors.

  5. X-ray diffraction and reflectivity validation of the depletion attraction in the competitive adsorption of lung surfactant and albumin.

    PubMed

    Stenger, Patrick C; Wu, Guohui; Miller, Chad E; Chi, Eva Y; Frey, Shelli L; Lee, Ka Yee C; Majewski, Jaroslaw; Kjaer, Kristian; Zasadzinski, Joseph A

    2009-08-05

    Lung surfactant (LS) and albumin compete for the air-water interface when both are present in solution. Equilibrium favors LS because it has a lower equilibrium surface pressure, but the smaller albumin is kinetically favored by faster diffusion. Albumin at the interface creates an energy barrier to subsequent LS adsorption that can be overcome by the depletion attraction induced by polyethylene glycol (PEG) in solution. A combination of grazing incidence x-ray diffraction (GIXD), x-ray reflectivity (XR), and pressure-area isotherms provides molecular-resolution information on the location and configuration of LS, albumin, and polymer. XR shows an average electron density similar to that of albumin at low surface pressures, whereas GIXD shows a heterogeneous interface with coexisting LS and albumin domains at higher surface pressures. Albumin induces a slightly larger lattice spacing and greater molecular tilt, similar in effect to a small decrease in the surface pressure. XR shows that adding PEG to the LS-albumin subphase restores the characteristic LS electron density profile at the interface, and confirms that PEG is depleted near the interface. GIXD shows the same LS Bragg peaks and Bragg rods as on a pristine interface, but with a more compact lattice corresponding to a small increase in the surface pressure. These results confirm that albumin adsorption creates a physical barrier that inhibits LS adsorption, and that PEG in the subphase generates a depletion attraction between the LS aggregates and the interface that enhances LS adsorption without substantially altering the structure or properties of the LS monolayer.

  6. X-Ray Diffraction and Reflectivity Validation of the Depletion Attraction in the Competitive Adsorption of Lung Surfactant and Albumin

    PubMed Central

    Stenger, Patrick C.; Wu, Guohui; Miller, Chad E.; Chi, Eva Y.; Frey, Shelli L.; Lee, Ka Yee C.; Majewski, Jaroslaw; Kjaer, Kristian; Zasadzinski, Joseph A.

    2009-01-01

    Abstract Lung surfactant (LS) and albumin compete for the air-water interface when both are present in solution. Equilibrium favors LS because it has a lower equilibrium surface pressure, but the smaller albumin is kinetically favored by faster diffusion. Albumin at the interface creates an energy barrier to subsequent LS adsorption that can be overcome by the depletion attraction induced by polyethylene glycol (PEG) in solution. A combination of grazing incidence x-ray diffraction (GIXD), x-ray reflectivity (XR), and pressure-area isotherms provides molecular-resolution information on the location and configuration of LS, albumin, and polymer. XR shows an average electron density similar to that of albumin at low surface pressures, whereas GIXD shows a heterogeneous interface with coexisting LS and albumin domains at higher surface pressures. Albumin induces a slightly larger lattice spacing and greater molecular tilt, similar in effect to a small decrease in the surface pressure. XR shows that adding PEG to the LS-albumin subphase restores the characteristic LS electron density profile at the interface, and confirms that PEG is depleted near the interface. GIXD shows the same LS Bragg peaks and Bragg rods as on a pristine interface, but with a more compact lattice corresponding to a small increase in the surface pressure. These results confirm that albumin adsorption creates a physical barrier that inhibits LS adsorption, and that PEG in the subphase generates a depletion attraction between the LS aggregates and the interface that enhances LS adsorption without substantially altering the structure or properties of the LS monolayer. PMID:19651036

  7. The effects of high density on the X-ray spectrum reflected from accretion discs around black holes

    NASA Astrophysics Data System (ADS)

    García, Javier A.; Fabian, Andrew C.; Kallman, Timothy R.; Dauser, Thomas; Parker, Michael L.; McClintock, Jeffrey E.; Steiner, James F.; Wilms, Jörn

    2016-10-01

    Current models of the spectrum of X-rays reflected from accretion discs around black holes and other compact objects are commonly calculated assuming that the density of the disc atmosphere is constant within several Thomson depths from the irradiated surface. An important simplifying assumption of these models is that the ionization structure of the gas is completely specified by a single, fixed value of the ionization parameter ξ, which is the ratio of the incident flux to the gas density. The density is typically fixed at ne = 1015 cm-3. Motivated by observations, we consider higher densities in the calculation of the reflected spectrum. We show by computing model spectra for ne ≳ 1017 cm-3 that high-density effects significantly modify reflection spectra. The main effect is to boost the thermal continuum at energies ≲ 2 keV. We discuss the implications of these results for interpreting observations of both active galactic nuclei and black hole binaries. We also discuss the limitations of our models imposed by the quality of the atomic data currently available.

  8. ON ESTIMATING THE HIGH-ENERGY CUTOFF IN THE X-RAY SPECTRA OF BLACK HOLES VIA REFLECTION SPECTROSCOPY

    SciTech Connect

    García, Javier A.; Steiner, James F.; McClintock, Jeffrey E.; Keck, Mason L.; Dauser, Thomas; Wilms, Jörn E-mail: jem@cfa.harvard.edu E-mail: keckm@bu.edu

    2015-08-01

    The fundamental parameters describing the coronal spectrum of an accreting black hole are the slope Γ of the power-law continuum and the energy E{sub cut} at which it rolls over. Remarkably, this latter parameter can be accurately measured for values as high as 1 MeV by modeling the spectrum of X-rays reflected from a black hole accretion disk at energies below 100 keV. This is possible because the details in the reflection spectrum, rich in fluorescent lines and other atomic features, are very sensitive to the spectral shape of the hardest coronal radiation illuminating the disk. We show that by fitting simultaneous NuSTAR (3–79 keV) and low-energy (e.g., Suzaku) data with the most recent version of our reflection model relxill one can obtain reasonable constraints on E{sub cut} at energies from tens of keV up to 1 MeV, for a source as faint as 1 mCrab in a 100 ks observation.

  9. The Effects of High Density on the X-ray Spectrum Reflected from Accretion Discs Around Black Holes

    NASA Technical Reports Server (NTRS)

    Garcia, Javier A.; Fabian, Andrew C.; Kallman, Timothy R.; Dauser, Thomas; Parker, Micahel L.; McClintock, Jeffrey E.; Steiner, James F.; Wilms, Jorn

    2016-01-01

    Current models of the spectrum of X-rays reflected from accretion discs around black holes and other compact objects are commonly calculated assuming that the density of the disc atmosphere is constant within several Thomson depths from the irradiated surface. An important simplifying assumption of these models is that the ionization structure of the gas is completely specified by a single, fixed value of the ionization parameter (xi), which is the ratio of the incident flux to the gas density. The density is typically fixed at n(sub e) = 10(exp 15) per cu cm. Motivated by observations, we consider higher densities in the calculation of the reflected spectrum. We show by computing model spectra for n(sub e) approximately greater than 10(exp 17) per cu cm that high-density effects significantly modify reflection spectra. The main effect is to boost the thermal continuum at energies 2 approximately less than keV. We discuss the implications of these results for interpreting observations of both active galactic nuclei and black hole binaries. We also discuss the limitations of our models imposed by the quality of the atomic data currently available.

  10. High-reflectance magnetron-sputtered scandium-based x-ray multilayer mirrors for the water window.

    PubMed

    Burcklen, C; de Rossi, S; Meltchakov, E; Dennetière, D; Capitanio, B; Polack, F; Delmotte, F

    2017-05-15

    We present an experimental comparison of several Sc-based short period multilayer mirrors including Cr/Sc with B4C barrier layers and CrNx/Sc, and we propose a new material combination that provides high reflectance in the water window domain. Multilayer samples with period thickness in the range 1.5-1.7 nm have been deposited by magnetron sputtering and characterized by x-ray reflectometry with a Cu-Kα source and with synchrotron radiation near the Sc-L2,3 edge. Best results are achieved by combining the nitridation of Cr layers and the addition of B4C barrier layers. Near normal incidence reflectance as high as 23% has been measured at photon energy of 397 eV. A simulation model of the multilayer structure is proposed and it predicts that reflectance higher than 32% is achievable with CrNx/B4C/Sc mirrors.

  11. A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence

    SciTech Connect

    Wobrauschek, P. Prost, J.; Ingerle, D.; Kregsamer, P.; Streli, C.; Misra, N. L.

    2015-08-15

    The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm{sup 2} active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-ray sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.

  12. A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence

    NASA Astrophysics Data System (ADS)

    Wobrauschek, P.; Prost, J.; Ingerle, D.; Kregsamer, P.; Misra, N. L.; Streli, C.

    2015-08-01

    The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm2 active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-ray sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.

  13. Orthoclase dissolution kinetics probed by in situ X-ray reflectivity: effects of temperature, pH, and crystal orientation

    NASA Astrophysics Data System (ADS)

    Fenter, P.; Park, C.; Cheng, L.; Zhang, Z.; Krekeler, M. P. S.; Sturchio, N. C.

    2003-01-01

    Initial dissolution kinetics at orthoclase (001) and (010) cleavage surfaces were measured for ˜2 to 7 monolayers as a function of temperature using in situ X-ray reflectivity. The sensitivity of X-ray reflectivity to probe mineral dissolution is discussed, including the applicability of this approach for different dissolution processes and the range of dissolution rates (˜10 -12 to 10 -6 mol/m 2/sec) that can be measured. Measurements were performed at pH 12.9 for the (001) surface and at pH 1.1 for the (001) and (010) surfaces at temperatures between 46 and 83°C. Dissolution at pH 12.9 showed a temperature-invariant process with an apparent activation energy of 65 ± 7 kJ/mol for the (001) cleavage surface consistent with previous powder dissolution results. Dissolution at pH 1.1 of the (001) and (010) surfaces revealed a similar process for both surfaces, with apparent activation energies of 87 ± 7 and 41 ± 7 kJ/mol, respectively, but with systematic differences in the dissolution process as a function of temperature. Longer-term measurements (five monolayers) show that the initial rates reported here at acidic pH are greater than steady-state rates by a factor of 2. Apparent activation energies at acidic pH differ substantially from powder dissolution results for K-feldspar; the present results bracket the value derived from powder dissolution measurements. The difference in apparent activation energies for the (001) and (010) faces at pH 1.1 reveals an anisotropy in dissolution kinetics that depends strongly on temperature. Our results imply a projected ˜25-fold change in the ratio of dissolution rates for the (001) and (010) surfaces between 25 and 90°C. The dissolution rate of the (001) surface is higher than that of the (010) surface above 51°C and is projected to be lower below this temperature. These results indicate clearly that the kinetics and energetics of orthoclase dissolution at acidic pH depend on crystal orientation. This dependence may

  14. Resonant soft X-ray reflectivity of ultrathin polymer films at the C-edge: A direct approach

    NASA Astrophysics Data System (ADS)

    Gibaud, Alain; Bal, Jayanta Kumar; Gullikson, Eric M.; Wang, Cheng; Vignaud, Guillaume

    2016-09-01

    The use of resonant soft X-ray reflectivity (RSXRR) in s-polarization is presented with the aim to show how far it is possible to go in the understanding the evolution of the refractive index n (E ) =1 -δ (E ) -i β (E ) of a ultrathin polystyrene film when the RSXRR is measured through the C-edge. We evidence that a direct fit to the data provides a very good estimation of δ (E ) and β (E ) in a large range of energies. Nevertheless, at some specific energy close to C-edge we observe that it is not possible to obtain a satisfactory fit to the data though the same formalism is applied to calculate the reflectivity. We show that even though we take into account the energy resolution of the incident beam, we still end up with a poor fit at these energies. Incorporating the strong contribution of 2nd order photons appeared near C-edge we could not eliminate the discrepancy. Probably the data normalisations have some impacts on such discrepancies at some specific energies.

  15. X-ray photonics: Bending X-rays with nanochannels

    NASA Astrophysics Data System (ADS)

    Pelliccia, Daniele

    2016-02-01

    X-ray counterparts of visible light optical elements are notoriously difficult to realize because the refractive index of all materials is close to unity. It has now been demonstrated that curved waveguides fabricated on a silicon chip can channel and deflect X-ray beams by consecutive grazing reflections.

  16. Hard X-Ray Emission of X-Ray Bursters

    NASA Technical Reports Server (NTRS)

    Kaaret, P.

    1999-01-01

    The primary goal of this proposal was to perform an accurate measurement of the broadband x-ray spectrum of a neutron-star low-mass x-ray binary found in a hard x-ray state. This goal was accomplished using data obtained under another proposal, which has provided exciting new information on the hard x-ray emission of neutron-star low-mass x-ray binaries. In "BeppoSAX Observations of the Atoll X-Ray Binary 4U0614+091", we present our analysis of the spectrum of 4U0614+091 over the energy band from 0.3-150 keV. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220 keV, or as a non-thermal powerlaw. Such a very hard x-ray spectrum has not been previously seen from neutron-star low-mass x-ray binaries. We also detected a spectral feature that can be interpreted as reprocessing, via Compton reflection, of the direct emission by an optically-thick disk and found a correlation between the photon index of the power-law tail and the fraction of radiation reflected which is similar to the correlation found for black hole candidate x-ray binaries and Seyfert galaxies. A secondary goal was to measure the timing properties of the x-ray emission from neutronstar low-mass x-ray binaries in their low/hard states.

  17. X-ray high-resolution diffraction and reflectivity studies of defects related to the mechanical treatment of ? single crystals

    NASA Astrophysics Data System (ADS)

    Mazur, K.; Sass, J.; Eichhorn, F.

    1998-07-01

    Triple-crystal x-ray diffractometry and x-ray reflectometry have been used to determine defects in 0953-8984/10/27/007/img7 epi-ready wafers caused by mechanical treatment. Reciprocal space maps around the 400 lattice point were separately made for mechanically polished wafers before and after etching treatment. The lattice imperfections have been studied by measuring the diffusion scattering. The surface morphology has been controlled by means of x-ray reflectometry. It was shown that measurements of diffuse scattering could be made with good sensitivity in a reasonable time when there was a moderate difference between the d spacing of the sample and the monochromator.

  18. Normalizing a relativistic model of X-ray reflection. Definition of the reflection fraction and its implementation in relxill

    NASA Astrophysics Data System (ADS)

    Dauser, T.; García, J.; Walton, , D. J.; Eikmann, W.; Kallman, T.; McClintock, J.; Wilms, J.

    2016-05-01

    Aims: The only relativistic reflection model that implements a parameter relating the intensity incident on an accretion disk to the observed intensity is relxill. The parameter used in earlier versions of this model, referred to as the reflection strength, is unsatisfactory; it has been superseded by a parameter that provides insight into the accretion geometry, namely the reflection fraction. The reflection fraction is defined as the ratio of the coronal intensity illuminating the disk to the coronal intensity that reaches the observer. Methods: The relxill model combines a general relativistic ray-tracing code and a photoionization code to compute the component of radiation reflected from an accretion that is illuminated by an external source. The reflection fraction is a particularly important parameter for relativistic models with well-defined geometry, such as the lamp post model, which is a focus of this paper. Results: Relativistic spectra are compared for three inclinations and for four values of the key parameter of the lamp post model, namely the height above the black hole of the illuminating, on-axis point source. In all cases, the strongest reflection is produced for low source heights and high spin. A low-spin black hole is shown to be incapable of producing enhanced relativistic reflection. Results for the relxill model are compared to those obtained with other models and a Monte Carlo simulation. Conclusions: Fitting data by using the relxill model and the recently implemented reflection fraction, the geometry of a system can be constrained. The reflection fraction is independent of system parameters such as inclination and black hole spin. The reflection-fraction parameter was implemented with the name refl_frac in all flavours of the relxill model, and the non-relativistic reflection model xillver, in v0.4a (18 January 2016).

  19. Normalizing a Relativistic Model of X-Ray Reflection Definition of the Reflection Fraction and Its Implementation in relxill

    NASA Technical Reports Server (NTRS)

    Dauser, T.; Garcia, J.; Walton, D. J.; Eikmann, W.; Kallman, T.; McClintock, J.; Wilms, J.

    2016-01-01

    Aims. The only relativistic reflection model that implements a parameter relating the intensity incident on an accretion disk to the observed intensity is relxill. The parameter used in earlier versions of this model, referred to as the reflection strength, is unsatisfactory; it has been superseded by a parameter that provides insight into the accretion geometry, namely the reflection fraction. The reflection fraction is defined as the ratio of the coronal intensity illuminating the disk to the coronal intensity that reaches the observer. Methods. The relxill model combines a general relativistic ray-tracing code and a photoionization code to compute the component of radiation reflected from an accretion that is illuminated by an external source. The reflection fraction is a particularly important parameter for relativistic models with well-defined geometry, such as the lamp post model, which is a focus of this paper. Results. Relativistic spectra are compared for three inclinations and for four values of the key parameter of the lamp post model,namely the height above the black hole of the illuminating, on-axis point source. In all cases, the strongest reflection is produced for low source heights and high spin. A low-spin black hole is shown to be incapable of producing enhanced relativistic reflection. Results for the relxill model are compared to those obtained with other models and a Monte Carlo simulation. Conclusions. Fitting data by using the relxill model and the recently implemented reflection fraction, the geometry of a system can be constrained. The reflection-fraction is independent of system parameters such as inclination and black hole spin. The reflection-fraction parameter was implemented with the name reflec_frac all flavours of the relxill model, and the non-relativistic reflection model xillver, in v0.4a (18 January 2016).

  20. Normalizing a Relativistic Model of X-Ray Reflection Definition of the Reflection Fraction and Its Implementation in relxill

    NASA Technical Reports Server (NTRS)

    Dauser, T.; Garcia, J.; Walton, D. J.; Eikmann, W.; Kallman, T.; McClintock, J.; Wilms, J.

    2016-01-01

    Aims. The only relativistic reflection model that implements a parameter relating the intensity incident on an accretion disk to the observed intensity is relxill. The parameter used in earlier versions of this model, referred to as the reflection strength, is unsatisfactory; it has been superseded by a parameter that provides insight into the accretion geometry, namely the reflection fraction. The reflection fraction is defined as the ratio of the coronal intensity illuminating the disk to the coronal intensity that reaches the observer. Methods. The relxill model combines a general relativistic ray-tracing code and a photoionization code to compute the component of radiation reflected from an accretion that is illuminated by an external source. The reflection fraction is a particularly important parameter for relativistic models with well-defined geometry, such as the lamp post model, which is a focus of this paper. Results. Relativistic spectra are compared for three inclinations and for four values of the key parameter of the lamp post model,namely the height above the black hole of the illuminating, on-axis point source. In all cases, the strongest reflection is produced for low source heights and high spin. A low-spin black hole is shown to be incapable of producing enhanced relativistic reflection. Results for the relxill model are compared to those obtained with other models and a Monte Carlo simulation. Conclusions. Fitting data by using the relxill model and the recently implemented reflection fraction, the geometry of a system can be constrained. The reflection-fraction is independent of system parameters such as inclination and black hole spin. The reflection-fraction parameter was implemented with the name reflec_frac all flavours of the relxill model, and the non-relativistic reflection model xillver, in v0.4a (18 January 2016).

  1. Asymmetric Structural Features in Single Supported Lipid Bilayers Containing Cholesterol and GM1 Resolved with Synchrotron X-Ray Reflectivity

    PubMed Central

    Reich, Christian; Horton, Margaret R.; Krause, Bärbel; Gast, Alice P.; Rädler, Joachim O.; Nickel, Bert

    2008-01-01

    The cell membrane comprises numerous protein and lipid molecules capable of asymmetric organization between leaflets and liquid-liquid phase separation. We use single supported lipid bilayers (SLBs) to model cell membranes, and study how cholesterol and asymmetrically oriented ganglioside receptor GM1 affect membrane structure using synchrotron x-ray reflectivity. Using mixtures of cholesterol, sphingomyelin, and 1,2-dioleoyl-sn-glycero-3-phosphocholine, we characterize the structure of liquid-ordered and liquid-disordered SLBs in terms of acyl-chain density, headgroup size, and leaflet thickness. SLBs modeling the liquid-ordered phase are 10 Å thicker and have a higher acyl-chain electron density (〈ρchain〉 = 0.33 e−/Å3) compared to SLBs modeling the liquid-disordered phase, or pure phosphatidylcholine SLBs (〈ρchain〉 = 0.28 e−/Å3). Incorporating GM1 into the distal bilayer leaflet results in membrane asymmetry and thickening of the leaflet of 4–9 Å. The structural effect of GM1 is more complex in SLBs of cholesterol/sphingomyelin/1,2-dioleoyl-sn-glycero-3-phosphocholine, where the distal chains show a high electron density (〈ρchain〉 = 0.33 e−/Å3) and the lipid diffusion constant is reduced by ∼50%, as measured by fluorescence microscopy. These results give quantitative information about the leaflet asymmetry and electron density changes induced by receptor molecules that penetrate a single lipid bilayer. PMID:18375517

  2. Is the Calcite-Water Interface Understood? Direct Comparisons of Molecular Dynamics Simulations with Specular X-ray Reflectivity Data

    SciTech Connect

    Fenter, Paul; Kerisit, Sebastien N.; Raiteri, Paolo; Gale, Julian D.

    2013-04-01

    New insights into the structure of the calcite-water interface are obtained through direct model-independent comparison of multiple classical molecular dynamics (MD) simulations with high-resolution specular X-ray reflectivity (XR) data. This set of comparisons, with four different state-of-the-art force fields (including two non-polarizable, one polarizable, and one reactive force field), reveal new insights into the absolute accuracy of the simulated structures and the uniqueness of the XR-derived structural results. These four simulations, while qualitatively similar, have visibly distinct interfacial structure, and are distinguished through a quantitative comparison of the XR signals calculated from these simulations with experimental XR data. The results demonstrate that the simulated calcite-water interface structures, as a whole, are not consistent with the XR data (i.e., within their precision and accuracy). This disagreement is largely due to the simulation of the calcite lattice. The simulated interfacial water profiles show substantially different levels of agreement with the XR data. Of these, the rigid-ion model (RIM) simulations show the best consistency with the experimental XR data. Further model-dependent comparisons of the structural parameters that describe the interfacial structure (derived from both the MD simulations and the XR data) provide further insight into the sources of differences between these two approaches. Using the new insights from the RIM simulations, new structures of the calcite-water interface consistent with both the experimental data and the simulation are identified and compared to recent results.

  3. Determination of some heavy metals (Fe, Cu, Zn and Pb) in blood by total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Bounakhla, M.; Doukkali, A.; Lalaoui, K.; Aguenaou, H.; Mokhtar, N.; Attrassi, B.

    2003-05-01

    The main purpose of this study is the interaction between nutrition (micronutrients heavy metals: Fe, Zn, Cu) and toxic heavy metals such as Pb in blood of children living in Gharb region of Morocco. This region receives all pollution carried by the Sebou river coming mainly from industrial activities. A rapid and simple analytical procedure was used for the determination of Fe, Cu and Zn trace amounts in blood by total-reflection X-ray fluorescence technique. This method is an energy dispersive XRF technique in a special geometry of primary beam, sample and detector. The sample is deposited on a plane polished surface of a suitable reflector material. It is presented as a few drops (25 μl) from a solution of blood digested in a mixture of HNO3 and H2O2 using a microwaves accelerated reaction system. The accuracy of measurements has been investigated by using certified materials. The concentration of Cu was found to be normal in all samples (\\cong1 ppm) which ruled out any interaction between this element and the others. On the other hand, amounts of Fe and Zn are very variables, suggesting an interaction between Fe and Zn. However, amounts of Pb in blood are inferior to 50 ppb, suggesting that no interaction exist with this metal and micronutrients.

  4. Intelligent Simultaneous Quantitative Online Analysis of Environmental Trace Heavy Metals with Total-Reflection X-Ray Fluorescence

    PubMed Central

    Ma, Junjie; Wang, Yeyao; Yang, Qi; Liu, Yubing; Shi, Ping

    2015-01-01

    Total-reflection X-ray fluorescence (TXRF) has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis. Simultaneous quantitative online analysis of trace heavy metals is urgently required by dynamic environmental monitoring and management, and TXRF has potential in this application domain. However, it calls for an online analysis scheme based on TXRF as well as a robust and rapid quantification method, which have not been well explored yet. Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis. This paper proposes an intelligent, multi-element quantification method according to the established online TXRF analysis platform. In the intelligent quantification method, collected characteristic curves of all existing elements and a pre-estimated background curve in the whole spectrum scope are used to approximate the measured spectrum. A novel hybrid algorithm, PSO-RBFN-SA, is designed to solve the curve-fitting problem, with offline global optimization and fast online computing. Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained. PMID:25954949

  5. Determination of arsenic in water samples by Total Reflection X-Ray Fluorescence using pre-concentration with alumina

    NASA Astrophysics Data System (ADS)

    Barros, Haydn; Marcó Parra, Lué-Merú; Bennun, Leonardo; Greaves, Eduardo D.

    2010-06-01

    The determination of arsenic in water samples requires techniques of high sensitivity. Total Reflection X-Ray Fluorescence (TXRF) allows the determination but a prior separation and pre-concentration procedure is necessary. Alumina is a suitable substrate for the selective separation of the analytes. A method for separation and pre-concentration in alumina, followed by direct analysis of the alumina is evaluated. Quantification was performed using the Al-Kα and Co-Kα lines as internal standard in samples prepared on an alumina matrix, and compared to a calibration with aqueous standards. Artificial water samples of As (III) and As (V) were analyzed after the treatment. Fifty milliliters of the sample at ppb concentration levels were mixed with 10 mg of alumina. The pH, time and temperature were controlled. The alumina was separated from the slurry by centrifugation, washed with de-ionized water and analyzed directly on the sample holder. A pre-concentration factor of 100 was found, with detection limit of 0.7 μgL -1. The percentage of recovery was 98% for As (III) and 95% for As (V) demonstrating the suitability of the procedure.

  6. Assessment of serum selenium levels in 2-month-old sucking calves using total reflection X-ray fluorescence technique

    NASA Astrophysics Data System (ADS)

    Buoso, M. C.; Ceccato, D.; Moschini, G.; Bernardini, D.; Testoni, S.; Torboli, A.; Valdes, M.

    2001-11-01

    The assessment of selenium status of livestock plays an important role in the production of medicine since low serum Se levels influence disease resistance in ruminants. It has been proved that Se deficiency may cause muscular dystrophy, cardiomyopathy and even death. Serum level has been widely used to evaluate the Se short-term status in animals since there is a good association between serum Se level and the dietary intake of the element over a wide range. The purpose of this work was to determine the Se serum concentration in a population of 78 sucking 2-month-old calves, in order to corroborate a clinical diagnosis of severe deficiency status. The samples were analyzed by total reflection X-ray fluorescence (TXRF) at the ITAL STRUCTURES Research Laboratory. The results obtained from the serum samples presented Se concentrations varying from 10 to 66 ng/ml. The comparison between the obtained values and the expected serum selenium values (60-80 ng/ml), confirmed a mild to severe deficiency status in the investigated population.

  7. Elemental analysis of tree leaves by total reflection X-ray fluorescence: New approaches for air quality monitoring.

    PubMed

    Bilo, Fabjola; Borgese, Laura; Dalipi, Rogerta; Zacco, Annalisa; Federici, Stefania; Masperi, Matteo; Leonesio, Paolo; Bontempi, Elza; Depero, Laura E

    2017-07-01

    This work shows that total reflection X-ray fluorescence (TXRF) is a fast, easy and successful tool to determine the presence of potentially toxic elements in atmospheric aerosols precipitations on tree leaves. Leaves are collected in eleven parks of different geographical areas of the Brescia city, Northern Italy, for environmental monitoring purposes. Two sample preparation procedures are considered: microwave acid digestion and the novel SMART STORE method for direct analysis. The latter consists in sandwiching a portion of the leaf between two organic foils, metals free, to save it from contamination and material loss. Mass composition of macro, micro and trace elements is calculated for digested samples, while relative elemental amount are obtained from direct analysis. Washed and unwashed leaves have a different composition in terms of trace elements. Differentiation occurs according to Fe, Pb and Cu contributions, considered as most representative of air depositions, and probably related to anthropogenic sources. Direct analysis is more representative of the composition of air precipitations. Advantages and drawbacks of the presented methods of sample preparation and TXRF analysis are discussed. Results demonstrate that TXRF allows to perform accurate and precise quantitative analysis of digested samples. In addition, direct analysis of leaves may be used as a fast and simple method for screening in the nanograms range.

  8. Analysis of inlet and outlet industrial wastewater effluents by means of benchtop total reflection X-ray fluorescence spectrometry.

    PubMed

    Marguí, E; Tapias, J C; Casas, A; Hidalgo, M; Queralt, I

    2010-06-01

    The monitoring of heavy metals in industrial waste water effluents is an important activity in many laboratories. Of special interest is the screening of elemental composition of inlet effluents and quantitative analysis of outlet effluents to study the efficiency of chemical treatment process to eliminate metals and to comply with current established concentration limits, respectively. In this sense, fast analytical methodologies which entail simple sample preparation are desired. In the present work, the possibilities and drawbacks of a benchtop total reflection X-ray fluorescence spectrometer (TXRF) for the rapid and simple determination of some inorganic impurities (As, Ba, Cd, Cu, Cr, Sn, Fe, Mn, Ni, Pb, Se and Zn) in inlet and outlet industrial waste water effluents from metallurgical and tanning leather factories have been tested. An evaluation of different simple sample treatments is presented and it is followed by a discussion of spectral and chemical matrix effects when dealing with this type of samples. Analytical figures of merit such as accuracy, precision and limits of detection have also been carefully studied. Finally, the data obtained by direct TXRF analysis has been compared to that obtained by ICP-OES/ICP-MS after a microwave digestion. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  9. On the Determination of the Spin of the Black Hole in Cyg X-1 from X-Ray Reflection Spectra

    NASA Technical Reports Server (NTRS)

    Fabian, A. C.; Wilkins, D.; Miller, J. M.; Reis, R. C.; Reynolds, C. S.; Cackett, E. M.; Nowak, M. A.; Pooley, G.; Pottschmidt, K.; Sanders, J. S.; Ross, R. R.; Wilms, J.

    2012-01-01

    The spin of Cygnus X-I is measured by fitting reflection models to Suzaku data covering the energy band 0.9-400 keY. The inner radius of the accretion disc is found to lie within 2 gravitational radii (rg = GM/c(exp 2)) and a value for the dimensionless black hole spin is obtained of 0.97(sup .0.14) (sup -0.02). This agrees with recent measurements using the continuum fitting method by Gou et al. and of the broad iron line by Duro et al. The disc inclination is measured at 23.7(sup +6.7) (sup -5.4) deg. which is consistent with the recent optical measurement of the binary system inclination by Orosz et al of 27+/- 0.8 deg. We pay special attention to the emissivity profile caused by irradiation of the inner disc by the hard power-law source. 1be X-ray observations and simulations show that the index q of that profile deviates from the commonly used, Newtonian, value of 3 within 3r(sub g), steepening considerably within 2r(sub g). as expected in the strong gravity regime.

  10. Analytical capabilities of total reflection X-ray fluorescence spectrometry for silver nanoparticles determination in soil adsorption studies

    NASA Astrophysics Data System (ADS)

    Torrent, Laura; Iglesias, Mònica; Hidalgo, Manuela; Marguí, Eva

    2016-12-01

    In recent years, the production of silver nanoparticles (AgNPs) has grown due to their antibacterial properties. This fact enhances the release of these particles into the environment, especially in soils that are the major sink. To better understand adsorption processes in soils, usually batch kinetic studies are carried out. In this context, we tested the possibilities of using total reflection X-ray fluorescence spectrometry (TXRF) to monitor the silver content in soil adsorption kinetic studies. It was found that the lower limit of detection for Ag (through Ag-Kα detection) in aqueous solutions was around 37 μg·L- 1, which was suitable to carry out this kind of studies. Moreover, the direct analysis of Ag adsorbed onto soil after the kinetic studies was investigated. In this case, the limit of detection for Ag was around 1.7 mg·kg- 1. All TXRF results were compared with those obtained by inductively coupled plasma optic emission spectrometry and good agreement was found. The batch adsorption tests performed showed that 98% of polyvinylpyrrolidone coated AgNPs were retained on the tested soils in < 6 h.

  11. Determination of trace element distribution in cancerous and normal human tissues by total reflection X-ray fluorescence analysis

    NASA Astrophysics Data System (ADS)

    von Czarnowski, D.; Denkhaus, E.; Lemke, K.

    1997-07-01

    The intention of this study was to establish a method for cancer diagnosis. For this purpose, different trace element distributions in carcinomas of the digestive tract and in normal tissues of human stomach, colon and rectum in correlation to the type of cancer were determined by total reflection X-ray fluorescence analysis (TXRF). The tissue samples were frozen and cut by a microtome into 10 μm sections, and a modified sample excision technique was introduced according to the aim of this research. After drying and spiking of the tissue sections, more than 20 elements, especially biologically relevant ones, were determined. The repeatabilities of measurements of element concentrations in malignant and normal tissues were calculated to be 10-30% (RSD) depending on the specific element. The concentration of Ca was found to be virtually constant (0.250±0.025 μg per 0.1 mm 3) in normal tissue and in carcinoma of the digestive organs. A significant diminution of Cr, Fe and Ni in carcinoma of the stomach, of Cr and Co in carcinoma of the colon and a significant accumulation of K in cancerous tissue of the colon and of Fe and K in neoplastic tissue of the rectum were discovered for a very limited population of patients.

  12. Inorganic pigment study of the San Pedro Gonzalez Telmo Sibyls using total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Vázquez, Cristina; Custo, Graciela; Barrio, Néstor; Burucúa, José; Boeykens, Susana; Marte, Fernando

    2010-09-01

    This article describes the study carried out on a series of oil paintings on canvas from the eighteenth century that were restored at Centro de Producción e Investigación en Restauración y Conservación Artística y Bibliográfica - Tarea (CEIRCAB-Tarea), Buenos Aires, Argentina: the San Pedro González Telmo Sibyls. Experimental study was undertaken to identify inorganic pigments and the technique used in their confection; and, in this way, try to add information about their local origin. Therefore special emphasis was put to infer technologies used in the manufacturing of these paintings. Elemental analysis was performed by total reflection X-ray fluorescence spectrometry (TXRF) and complemented by optical and polarized light microscopy. Microsampling was carefully done over areas of the paintings which were damaged and where a small additional loss will not be noticed. This investigation has shown that a variety of pigments were used, namely earth pigments (red and yellow ochres), white lead, vermilion, etc., and they were used either pure or in mixtures. This characterization helped conservators in their decisions regarding a better understanding of the deterioration processes. In addition, this research about the material composition allowed the art historians and restorers the possibility to obtain information about where, when or by whom The San Pedro González Telmo Sibyls may have been painted.

  13. Determination of platinum group metal catalyst residues in active pharmaceutical ingredients by means of total reflection X-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Marguí, Eva; Queralt, Ignasi; Hidalgo, Manuela

    2013-08-01

    The control of metal catalyst residues (i.e., platinum group metals (PGMs)) in different stages of the manufacturing processes of the active pharmaceutical ingredients (APIs) and, especially, in the final product is crucial. For API specimens, there are strict guidelines to limit the levels of metal residues based on their individual levels of safety concern. For PGMs the concentration limit has been established at 10 mg/kg in the API. Therefore great effort is currently being devoted to the development of new and simple procedures to control metals in pharmaceuticals. In the present work, an analytical methodology based on benchtop total reflection X-ray fluorescence spectrometry (TXRF) has been developed for the rapid and simple determination of some PGM catalyst impurities (Rh, Pd, Ir and Pt) in different types of API samples. An evaluation of different sample treatments (dissolution and digestion of the solid pharmaceutical samples) has been carried out and the developed methodologies have been validated according to the analytical parameters to be considered and acceptance criteria for PGM determination according to the United States Pharmacopeia (USP). Limits of quantification obtained for PGM metals were in the range of 2-4 mg/kg which are satisfactory according to current legislation. From the obtained results it is shown that the developed TXRF method can be implemented in the pharmaceutical industries to increase productivity of the laboratory; offering an interesting and complementary analytical tool to other atomic spectroscopic methods.

  14. Element determination in natural biofilms of mine drainage water by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Mages, Margarete; von Tümpling, Wolf; van der Veen, Andrea; Baborowski, Martina

    2006-11-01

    Human impacts like mining activities lead to higher element concentration in surface waters. For different pollution levels, the consequences for aquatic organisms are not yet investigated in detail. Therefore, the aim of this investigation is to determine the influence of mining affected surface waters on biofilms. Elements like heavy metals can be absorbed on cell walls and on polymeric substances or enter the cytoplasm of the cells. Thus, they are important for the optimization of industrial biotechnological processes and the environmental biotechnology. Beyond this, biofilms can also play an important role in wastewater treatment processes and serve as bioindicators in the aquatic environment. The presented total reflection X-ray fluorescence spectroscopic investigation was performed to compare the element accumulation behavior of biofilms grown on natural or on artificial materials of drainage water affected by former copper mining activities. A high salt and heavy metal pollution is characteristic for the drainage water. For an assessment of these results, samples from stream Schlenze upstream the confluence with the drainage water, a small tributary of the Saale River in central Germany, were analyzed, too.

  15. Interfacial Properties and Iron Binding to Bacterial Proteins That Promote the Growth of Magnetite Nanocrystals: X-ray Reflectivity and Surface Spectroscopy Studies

    SciTech Connect

    Wang, Wenjie; Bu, Wei; Wang, Lijun; Palo, Pierre E.; Mallapragada, Surya; Nilsen-Hamilton, Marit; Vaknin, David

    2012-04-30

    Surface sensitive X-ray scattering and spectroscopic studies have been conducted to determine structural properties of Mms6, the protein in Magnetospirillum magneticum AMB-1 that is implicated as promoter of magnetite nanocrystals growth. Surface pressure versus molecular area isotherms indicate Mms6 forms stable monolayers at the aqueous/vapor interface that are strongly affected by ionic conditions of the subphase. Analysis of X-ray reflectivity from the monolayers shows that the protein conformation at the interface depends on surface pressure and on the presence of ions in the solutions, in particular of iron ions and its complexes. X-ray fluorescence at grazing angles of incidence from the same monolayers allows quantitative determination of surface bound ions to the protein showing that ferric iron binds to Mms6 at higher densities compared to other ions such as Fe{sup 2+} or La{sup 3+} under similar buffer conditions.

  16. X-ray reflectivities, at low and high order of reflection, of flat highly oriented pyrolytic graphite crystals

    NASA Astrophysics Data System (ADS)

    Chabot, M.; Nicolai, P.; Wohrer, K.; Rozet, J. P.; Touati, A.; Chetioui, A.; Vernhet, D.; Politis, M. F.

    1991-10-01

    Integrated reflectivities of flat highly oriented pyrolytic graphite crystals have been measured at various energies (5.9 ≤ E ≤ 15.10 keV) and for various orders of reflection n (1 ≤ n ≤ 5). For low n values, the reflectivity is severely affected by secondary extinction; our results show that the theory of Zachariasen represents the experiment reasonably well, a conclusion reached by other authors for the case of n = 1 reflections. For high n values, the reflectivity is more sensitive to the structure factor's temperature correction, a quantity not precisely known. Our measurements are in favour of the larger temperature correction within the range reported in the literature.

  17. Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

    NASA Technical Reports Server (NTRS)

    Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B.; Allen, Maxwell J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C., Jr.

    1991-01-01

    The Multispectral Solar Telescope Array is a rocket-borne observatory which encompasses seven compact soft X-ray/EUV, multilayer-coated, and two compact far-UV, interference film-coated, Cassegrain and Ritchey-Chretien telescopes. Extensive measurements are presented on the efficiency and spectral bandpass of the X-ray/EUV telescopes. Attention is given to systematic errors and measurement errors.

  18. Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

    NASA Technical Reports Server (NTRS)

    Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B.; Allen, Maxwell J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C., Jr.

    1991-01-01

    The Multispectral Solar Telescope Array is a rocket-borne observatory which encompasses seven compact soft X-ray/EUV, multilayer-coated, and two compact far-UV, interference film-coated, Cassegrain and Ritchey-Chretien telescopes. Extensive measurements are presented on the efficiency and spectral bandpass of the X-ray/EUV telescopes. Attention is given to systematic errors and measurement errors.

  19. X-Ray Reflection and an Exceptionally Long Thermonuclear Helium Burst from IGR J17062-6143

    NASA Technical Reports Server (NTRS)

    Keek, L.; Iwakiri, W.; Serino, M.; Ballantyne, D. R.; in’t Zand, J. J. M.; Strohmayer, T. E.

    2017-01-01

    Thermonuclear X-ray bursts from accreting neutron stars power brief but strong irradiation of their surroundings, providing a unique way to study accretion physics. We analyze MAXI/Gas Slit Camera and Swift/XRT spectra of a day-long flash observed from IGR J17062-6143 in 2015. It is a rare case of recurring bursts at a low accretion luminosity of 0.15% Eddington. Spectra from MAXI, Chandra, and NuSTAR observations taken between the 2015 burst and the previous one in 2012 are used to determine the accretion column. We find it to be consistent with the burst ignition column of 5x10(exp 10) g cm (exp -2), which indicates that it is likely powered by burning in a deep helium layer. The burst flux is observed for over a day, and decays as a straight power law: F gamma t (exp -1.15). The burst and persistent spectra are well described by thermal emission from the neutron star, Comptonization of this emission in a hot optically thin medium surrounding the star, and reflection off the photoionized accretion disk. At the burst peak, the Comptonized component disappears, when the burst may dissipate the Comptonizing gas, and it returns in the burst tail. The reflection signal suggests that the inner disk is truncated at approximately 102 gravitational radii before the burst, but may move closer to the star during the burst. At the end of the burst, the flux drops below the burst cooling trend for 2 days, before returning to the pre-burst level.

  20. X-Ray Reflection and an Exceptionally Long Thermonuclear Helium Burst from IGR J17062-6143

    NASA Technical Reports Server (NTRS)

    Keek, L.; Iwakiri, W.; Serino, M.; Ballantyne, D. R.; in’t Zand, J. J. M.; Strohmayer, T. E.

    2017-01-01

    Thermonuclear X-ray bursts from accreting neutron stars power brief but strong irradiation of their surroundings, providing a unique way to study accretion physics. We analyze MAXI/Gas Slit Camera and Swift/XRT spectra of a day-long flash observed from IGR J17062-6143 in 2015. It is a rare case of recurring bursts at a low accretion luminosity of 0.15% Eddington. Spectra from MAXI, Chandra, and NuSTAR observations taken between the 2015 burst and the previous one in 2012 are used to determine the accretion column. We find it to be consistent with the burst ignition column of 5x10(exp 10) g cm (exp -2), which indicates that it is likely powered by burning in a deep helium layer. The burst flux is observed for over a day, and decays as a straight power law: F gamma t (exp -1.15). The burst and persistent spectra are well described by thermal emission from the neutron star, Comptonization of this emission in a hot optically thin medium surrounding the star, and reflection off the photoionized accretion disk. At the burst peak, the Comptonized component disappears, when the burst may dissipate the Comptonizing gas, and it returns in the burst tail. The reflection signal suggests that the inner disk is truncated at approximately 102 gravitational radii before the burst, but may move closer to the star during the burst. At the end of the burst, the flux drops below the burst cooling trend for 2 days, before returning to the pre-burst level.

  1. X-Ray Reflection and an Exceptionally Long Thermonuclear Helium Burst from IGR J17062-6143

    NASA Astrophysics Data System (ADS)

    Keek, L.; Iwakiri, W.; Serino, M.; Ballantyne, D. R.; in’t Zand, J. J. M.; Strohmayer, T. E.

    2017-02-01

    Thermonuclear X-ray bursts from accreting neutron stars power brief but strong irradiation of their surroundings, providing a unique way to study accretion physics. We analyze MAXI/Gas Slit Camera and Swift/XRT spectra of a day-long flash observed from IGR J17062-6143 in 2015. It is a rare case of recurring bursts at a low accretion luminosity of 0.15% Eddington. Spectra from MAXI, Chandra, and NuSTAR observations taken between the 2015 burst and the previous one in 2012 are used to determine the accretion column. We find it to be consistent with the burst ignition column of 5 × 1010 g cm‑2, which indicates that it is likely powered by burning in a deep helium layer. The burst flux is observed for over a day, and decays as a straight power law: F ∝ t ‑1.15. The burst and persistent spectra are well described by thermal emission from the neutron star, Comptonization of this emission in a hot optically thin medium surrounding the star, and reflection off the photoionized accretion disk. At the burst peak, the Comptonized component disappears, when the burst may dissipate the Comptonizing gas, and it returns in the burst tail. The reflection signal suggests that the inner disk is truncated at ∼102 gravitational radii before the burst, but may move closer to the star during the burst. At the end of the burst, the flux drops below the burst cooling trend for 2 days, before returning to the pre-burst level.

  2. Performance of a reflection-type polarizer by use of muscovite mica crystal in the soft x-ray region of 1 keV

    SciTech Connect

    Imazono, Takashi; Ishino, Masahiko; Koike, Masato; Kimura, Hiroaki; Hirono, Toko; Sano, Kazuo

    2005-02-01

    To develop the polarizer functioning in the soft x-ray region of 1 keV, the polarization performance of muscovite mica has been investigated theoretically with a simulation code based on dynamical theory. As the result of calculation, muscovite mica is found to be a promising candidate as a reflection-type polarizer with the reflectivity for s polarization of 0.03 at approximately 0.9 keV at the angle of incidence of 45 deg. In order to verify the polarization performance of muscovite mica experimentally, a symmetric Bragg reflection measurement of muscovite mica(002) was carried out using a linearly polarized undulator radiation. As a result, the maximum reflectivity for s polarization and the extinction ratio of muscovite mica were approximately 0.018 and 200 at 878 eV, respectively. This result indicates that muscovite mica works as a practical polarizer in the soft x-ray region.

  3. On symmetric X-ray beam splitting with high efficiency by use of reflection gratings with rectangular profile in the extreme off-plane configuration.

    PubMed

    Jark, Werner; Eichert, Diane

    2015-08-24

    In order to be reflected or diffracted off a surface structure soft X-rays and hard X-rays need to impinge at grazing angles of incidence onto the surface. In case of a reflection grating of highly symmetric structure with rectangular groove profile these grooves can be oriented parallel to the beam trajectory. In such a symmetric situation the distribution of the diffracted intensity with respect to the plane of incidence is then expected to be symmetric. This is indeed observed with symmetrically oriented diffraction peaks. It can be predicted that for appropriate structure parameters the intensity can be contained mostly in two symmetrically oriented diffraction peaks. This will also be the case for hard X-rays. The diffraction efficiency will be particularly high, when the angle of grazing incidence is chosen in the total reflection regime below the critical angle of the grating coating. These predictions were experimentally verified in this work for hard X-rays with photon energies between 4 keV and 12.4 keV. In the experiment of the order of 30% of the incident intensity was diffracted into the two first orders. This is to be compared to reflectivities of the order of 50% measured at the same coating in an unruled area of the substrate. Consequently the relative structural diffraction efficiency for each first order was about 30%, while ideally it could have been 40%. The presented grating structure will thus be a rather efficient amplitude beam splitter for hard X-rays, e.g. in the coherent beam from a free electron laser. In addition such object could then be used as the first component in Michelson interferometers for the beam characterisation or for introducing a time delay between two coherent beams.

  4. X-ray optics: Diamond brilliance

    NASA Astrophysics Data System (ADS)

    Durbin, Stephen M.; Colella, Roberto

    2010-03-01

    Most materials either absorb or transmit X-rays. This is useful for imaging but makes it notoriously difficult to build mirrors for reflective X-ray optics. A demonstration of the high X-ray reflectivity of diamond could provide a timely solution to make the most of the next generation of free-electron lasers.

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

    DOEpatents

    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.

  6. Physical interactions of fish protamine and antisepsis peptide drugs with bacterial membranes revealed by combination of specular x-ray reflectivity and grazing-incidence x-ray fluorescence.

    PubMed

    Abuillan, Wasim; Schneck, Emanuel; Körner, Alexander; Brandenburg, Klaus; Gutsmann, Thomas; Gill, Tom; Vorobiev, Alexei; Konovalov, Oleg; Tanaka, Motomu

    2013-07-01

    As a defined model of outer membranes of gram negative bacteria, we investigated the interaction of monolayers of lipopolysacchrides from Salmonella enterica rough strains R90 (LPS Ra) with natural and synthetic peptides. The fine structures perpendicular to the membrane plane and the ion distribution near the interface were determined by specular x-ray reflectivity (XRR) and grazing-incidence x-ray fluorescence (GIXF) in the presence and absence of divalent cations. The unique combination of XRR and GIXF allows for the quantitative identification of different modes of interactions in a high spatial resolution, which cannot be assessed by other experimental methods. Natural fish protamine disrupts the stratified membrane structures in the absence of Ca(2+) ions, while staying away from the membrane surface in the presence of Ca(2+) ions. In contrast, synthetic antisepsis peptide Pep 19-2.5 weakly adsorbs to the membrane and stays near the uncharged sugar units even in the absence of Ca(2+). In the presence of Ca(2+), Pep 19-2.5 can reach the negatively charged inner core without destroying the barrier capability against ions.

  7. Physical interactions of fish protamine and antisepsis peptide drugs with bacterial membranes revealed by combination of specular x-ray reflectivity and grazing-incidence x-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Abuillan, Wasim; Schneck, Emanuel; Körner, Alexander; Brandenburg, Klaus; Gutsmann, Thomas; Gill, Tom; Vorobiev, Alexei; Konovalov, Oleg; Tanaka, Motomu

    2013-07-01

    As a defined model of outer membranes of gram negative bacteria, we investigated the interaction of monolayers of lipopolysacchrides from Salmonella enterica rough strains R90 (LPS Ra) with natural and synthetic peptides. The fine structures perpendicular to the membrane plane and the ion distribution near the interface were determined by specular x-ray reflectivity (XRR) and grazing-incidence x-ray fluorescence (GIXF) in the presence and absence of divalent cations. The unique combination of XRR and GIXF allows for the quantitative identification of different modes of interactions in a high spatial resolution, which cannot be assessed by other experimental methods. Natural fish protamine disrupts the stratified membrane structures in the absence of Ca2+ ions, while staying away from the membrane surface in the presence of Ca2+ ions. In contrast, synthetic antisepsis peptide Pep 19-2.5 weakly adsorbs to the membrane and stays near the uncharged sugar units even in the absence of Ca2+. In the presence of Ca2+, Pep 19-2.5 can reach the negatively charged inner core without destroying the barrier capability against ions.

  8. Quantitative determination on heavy metals in different stages of wine production by Total Reflection X-ray Fluorescence and Energy Dispersive X-ray Fluorescence: Comparison on two vineyards

    NASA Astrophysics Data System (ADS)

    Pessanha, Sofia; Carvalho, Maria Luisa; Becker, Maria; von Bohlen, Alex

    2010-06-01

    The purpose of this study is to determine the elemental content, namely heavy metals, of samples of vine-leaves, grapes must and wine. In order to assess the influence of the vineyard age on the elemental content throughout the several stages of wine production, elemental determinations of trace elements were made on products obtained from two vineyards aged 6 and 14 years from Douro region. The elemental content of vine-leaves and grapes was determined by Energy Dispersive X-Ray Fluorescence (EDXRF), while analysis of the must and wine was performed by Total Reflection X-ray Fluorescence (TXRF). Almost all elements present in wine and must samples did not exceed the recommended values found in literature for wine. Bromine was present in the 6 years old wine in a concentration 1 order of magnitude greater than what is usually detected. The Cu content in vine-leaves from the older vineyard was found to be extremely high probably due to excessive use of Cu-based fungicides to control vine downy mildew. Higher Cu content was also detected in grapes although not so pronounced. Concerning the wine a slightly higher level was detected on the older vineyard, even so not exceeding the recommended value.

  9. Impact of Lipid Oxidization on Vertical Structures and Electrostatics of Phospholipid Monolayers Revealed by Combination of Specular X-ray Reflectivity and Grazing-Incidence X-ray Fluorescence.

    PubMed

    Korytowski, Agatha; Abuillan, Wasim; Makky, Ali; Konovalov, Oleg; Tanaka, Motomu

    2015-07-30

    The influence of phospholipid oxidization of floating monolayers on the structure perpendicular to the global plane and on the density profiles of ions near the lipid monolayer has been investigated by a combination of grazing incidence X-ray fluorescence (GIXF) and specular X-ray reflectivity (XRR). Systematic variation of the composition of the floating monolayers unravels changes in the thickness, roughness and electron density of the lipid monolayers as a function of molar fraction of oxidized phospholipids. Simultaneous GIXF measurements enable one to qualitatively determine the element-specific density profiles of monovalent (K(+) or Cs(+)) and divalent ions (Ca(2+)) in the vicinity of the interface in the presence and absence of two types of oxidized phospholipids (PazePC and PoxnoPC) with high spatial accuracy (±5 Å). We found the condensation of Ca(2+) near carboxylated PazePC was more pronounced compared to PoxnoPC with an aldehyde group. In contrast, the condensation of monovalent ions could hardly be detected even for pure oxidized phospholipid monolayers. Moreover, pure phospholipid monolayers exhibited almost no ion specific condensation near the interface. The quantitative studies with well-defined floating monolayers revealed how the elevation of lipid oxidization level alters the structures and functions of cell membranes.

  10. Determination of metal-cofactors in enzyme complexes by total-reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Wittershagen, A.; Rostam-Khani, P.; Klimmek, O.; Groß, R.; Zickermann, V.; Zickermann, I.; Gemeinhardt, S.; Kröger, A.; Ludwig, B.; Kolbesen, B. O.

    1997-07-01

    The determination of metal-cofactors and their molar concentrations is an important requirement for the characterisation of metalloproteins and a challenge regarding the capabilities of trace analytical methods. In this respect, total-reflection X-ray fluorescence spectrometry offers many advantages for the determination of trace elements in enzymes, as compared to other well known analytical techniques such as flame atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry (ICP-AES), because of the significantly smaller amounts of sample required. Without any decomposition, elements like P, S, Fe, Ni, Cu, Zn, Mn and Mo could be determined with high accuracy, in spite of the large bio-organic matrix. The enzymes (polysulphide reductase and hydrogenase of the rumen bacterium Wolinella succinogenes, and the cytochrome c oxidase and quinol oxidase of the soil bacterium Paracoccus denitrificans) were transferred from their usual salt-buffer into a solution of 100 mmol l -1 tris(hydroxymethyl)aminomethane (tris)-acetate containing an appropriate detergent. By this procedure, an improved signal-to-noise ratio is obtained. The polysulphide reductase was found to contain copper as a hitherto existing unknown cofactor. The enzyme contains a stretch of amino acids that are typical of copper proteins and thus confirm the presence of this element. Furthermore, the data concerning cytochrome c oxidase from Paracoccus denitrificans are in good agreement with published values obtained by ICP-AES. Also, results from measurements with the quinol oxidase from the same bacterium agree with the expected values. The investigations lead to the conclusion that the method is well suited to the quantitative determination of metals in enzymes, in particular their molar fractions, and requires only small amounts of the biological sample without any extensive pretreatment.

  11. Determination of As concentration in earthworm coelomic fluid extracts by total-reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Allegretta, Ignazio; Porfido, Carlo; Panzarino, Onofrio; Fontanella, Maria Chiara; Beone, Gian Maria; Spagnuolo, Matteo; Terzano, Roberto

    2017-04-01

    Earthworms are often used as sentinel organisms to study As bioavailability in polluted soils. Arsenic in earthworms is mainly sequestrated in the coelomic fluids whose As content can therefore be used to asses As bioavalability. In this work, a method for determining As concentration in coelomic fluid extracts using total-reflection X-ray fluorescence spectrometry (TXRF) is presented. For this purpose coelomic fluid extracts from earthworms living in three polluted soils and one non-polluted (control) soil have been collected and analysed. A very simple sample preparation was implemented, consisting of a dilution of the extracts with polyvinyl alcohol (PVA) using a 1:8 ratio and dropwise deposition of the sample on the reflector. A detection limit of 0.2 μg/l and quantification limit of 0.6 μg/l was obtained in the diluted samples, corresponding to 2 μg/l and 6 μg/l in the coelomic fluid extracts, respectively. This allowed to quantify As concentration in coelomic fluids extracted from earthworms living in soils polluted with As at concentrations higher than 20 mg/kg (considered as a pollution threshold for agricultural soils). The TXRF method has been validated by comparison with As concentrations in standards and by analysing the same samples by ICP-MS, after acid digestion of the sample. The low limit of detection, the proven reliability of the method and the little sample preparation make TXRF a suitable, cost-efficient and "green" technique for the analysis of As in earthworm coelomic fluid extracts for bioavailability studies.

  12. Quantitative analysis of total reflection X-ray fluorescence from finely layered structures using XeRay

    NASA Astrophysics Data System (ADS)

    Gong, Zhiliang; Kerr, Daniel; Hwang, Hyeondo Luke; Henderson, J. Michael; Suwatthee, Tiffany; Slaw, Benjamin R.; Cao, Kathleen D.; Lin, Binhua; Bu, Wei; Lee, Ka Yee C.

    2017-03-01

    Total reflection x-ray fluorescence (TXRF) is a widely applicable experimental technique for studying chemical element distributions across finely layered structures at extremely high sensitivity. To promote and facilitate scientific discovery using TXRF, we developed a MATLAB-based software package with a graphical user interface, named XeRay, for quick, accurate, and intuitive data analysis. XeRay lets the user model any layered system, each layer with its independent chemical composition and thickness, and enables fine-tuned data fitting. The accuracy of XeRay has been tested in the analysis of TXRF data from both air/liquid interface and liquid/liquid interfacial studies and has been compared to literature results. In an air/liquid interface study, Ca2+ sequestration was measured at a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidic acid (SOPA) on a buffer solution of 1 mM CaCl2 at pH 7.5. Data analysis with XeRay reveals that each 1 nm2 of interfacial area contains 2.38 ± 0.06 Ca2+ ions, which corresponds to a 1:1 ratio between SOPA headgroups and Ca2+ ions, consistent with several earlier reports. For the liquid/liquid interface study of Sr2+ enrichment at the dodecane/surfactant/water interface, analysis using XeRay gives a surface enrichment of Sr2+ at 68-5+6 Å2 per ion, consistent with the result published for the same dataset.

  13. Zinc and cadmium accumulation in single zebrafish ( Danio rerio) embryos — A total reflection X-ray fluorescence spectrometry application

    NASA Astrophysics Data System (ADS)

    Mages, Margarete; Bandow, Nicole; Küster, Eberhard; Brack, Werner; von Tümpling, Wolf

    2008-12-01

    Trace metals such as Cadmium (Cd) and Zinc (Zn) are known to exhibit adverse effects on many aquatic organisms including early life stages of fish. In contact with contaminated sediment, fish eggs and embryos may be exposed to metals via the water phase as well as via direct contact with contaminated particles. This may result in body burdens that are difficult to predict and may vary according to individual micro scale exposure conditions. The highly sensitive total reflection X-ray fluorescence spectrometry (TXRF) may provide a tool to analyse individual embryos for internal contaminant concentrations and thus helps to develop a better understanding of dose-response relationships. To test this hypothesis, embryos of Danio rerio were exposed to Cd and Zn spiked sediment in different treatments applying an ion exchange resin for modification of bioavailable concentrations. The TXRF analysis indicated individual embryos with dramatically enhanced exposure compared to other individuals despite uniform exposure conditions on a macro scale. Ion exchanger reduced embryo Zn concentrations to values close to control value with a comparably low standard deviation. Cadmium concentrations in embryos were in the range of 4000 to 7000 µg/g with a median of 5740 µg/g. A commercial ion exchanger reduced individual body burdens by a factor 50 to 100. Individual peak body burdens of up to 3160 µg/g were accompanied by reduced weight of the fish eggs due to early death i.e. coagulation. The investigation of exposure and effects on an individual-based scale may significantly help to reduce uncertainty and inconsistencies occurring in conventional analysis of pooled fish embryo samples.

  14. Determination of trace elements in freshwater rotifers and ciliates by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Woelfl, S.; Óvári, M.; Nimptsch, J.; Neu, T. R.; Mages, M.

    2016-02-01

    Element determination in plankton is important for the assessment of metal contamination of aquatic environments. Until recently, it has been difficult to determine elemental content in rotifers or ciliates derived from natural plankton samples because of the difficulty in handling and separation of these fragile organisms. The aim of this study was to evaluate methods for separation of rotifers and large ciliates from natural plankton samples (μg range dry weight) and subsequent analysis of their elemental content using total-reflection X-ray fluorescence spectrometry (TXRF). Plankton samples were collected from different aquatic environments (three lakes, one river) in Chile, Argentina and Hungary. From one to eighty specimens of five rotifer species (Brachionus calyciflorus, Brachionus falcatus, Asplanchna sieboldii, Asplanchna sp., Philodina sp.) and four to twelve specimens of one large ciliate (Stentor amethystinus) were prepared according to the dry method originally developed for microcrustaceans, and analysed by TRXF following in situ microdigestion. Our results demonstrated that it possible to process these small and fragile organisms (individual dry mass: 0.17-9.39 μg ind- 1) via careful washing and preparation procedures. We found species-dependent differences of the element mass fractions for some of the elements studied (Cr, Mn, Fe, Ni, Cu, Zn, As, Pb), especially for Cu, Fe and Mn. One large rotifer species (A. sieboldii) also showed a negative correlation between individual dry weight and the element content for Pb, Ni and Cr. We conclude that our application of the in situ microdigestion-TRXF method is suitable even for rotifers and ciliates, greatly expanding the possibilities for use of plankton in biomonitoring of metal contamination in aquatic environments.

  15. Total reflection X-ray fluorescence analysis of oral fluids of women affected by osteoporosis and osteopenia

    NASA Astrophysics Data System (ADS)

    Sánchez, Héctor Jorge; Valentinuzzi, María Cecilia; Grenón, Miram; Abraham, José

    2008-12-01

    Osteoporosis is a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures; the early stage of decreased bone density is called osteopenia. More than 200 million people are affected and about 50% of post-menopausic women are expected to develop the disease. Osteoporosis, osteopenia and periodontal disease have in common several risk factors, being hyperthyroidism and smoking habits the most important ones. There is scarce information in the literature about the association between periodontal disease and osteoporosis and/or osteopenia. Some works suggest that osteoporotic women are susceptible to a higher loss of periodontal insertion, alveolar bones, and teeth. Thirty adult post-menopausic women were studied; some of them were healthy (control group) and the rest of them were undergoing some stage of osteoporosis or osteopenia. All the subjects were healthy, non-smokers, not having dental implants, and with communitarian periodontal index higher than 1(CPI > 1). Samples of saliva and gingival crevice fluid were extracted with calibrated micro-capillaries and deposited on Si reflectors. Known amounts of Ga were added to the samples in order to act as internal standard for quantification by the total reflection x-ray fluorescence technique. Experimental concentrations of several elements (P, S, Cl, K, Ca, Cr, Fe, NI, Cu, and Zn) were determined. The concentration of some elements in saliva showed different behavior as compared to gingival crevice fluid. Some critical elements of bone composition, such as Ca and Zn, present very distinguishable behavior. Improvements in the statistics are required for a better assessment of a routine method and to establish some correlation with periodontal disease. TXRF seems to be a promising method to evaluate the evolution of osteoporosis.

  16. Application of CO2 Snow Jet Cleaning in Conjunction with Laboratory Based Total Reflection X-Ray Fluorescence

    NASA Technical Reports Server (NTRS)

    Schmeling, M.; Burnett, D. S.; Allton, J. H.; Rodriquez, M.; Tripa, C. E.; Veryovkin, I. V.

    2013-01-01

    The Genesis mission was the first mission returning solar material to Earth since the Apollo program [1,2]. Unfortunately the return of the space craft on September 8, 2004 resulted in a crash landing, which shattered the samples into small fragments and exposed them to desert soil and other debris. Thus only small fragments of the original collectors are available, each having different degrees of surface contamination. Thorough surface cleaning is required to allow for subsequent analysis of solar wind material embedded within. An initial cleaning procedure was developed in coordination with Johnson Space Center which focused on removing larger sized particulates and a thin film organic contamination acquired during collection in space [3]. However, many of the samples have additional residues and more rigorous and/or innovative cleaning steps might be necessary. These cleaning steps must affect only the surface to avoid leaching and re-distribution of solar wind material from the bulk of the collectors. To aid in development and identification of the most appropriate cleaning procedures each sample has to be thoroughly inspected before and after each cleaning step. Laboratory based total reflection X-ray fluorescence (TXRF) spectrometry lends itself to this task as it is a non-destructive and surface sensitive analytical method permitting analysis of elements from aluminum onward present at and near the surface of a flat substrate [4]. The suitability of TXRF has been demonstrated for several Genesis solar wind samples before and after various cleaning methods including acid treatment, gas cluster ion beam, and CO2 snow jet [5 - 7]. The latter one is non-invasive and did show some promise on one sample [5]. To investigate the feasibility of CO2 snow jet cleaning further, several flown Genesis samples were selected to be characterized before and after CO2 snow application with sample 61052 being discussed below.

  17. Ultra-short-period W/B4C multilayers for x-ray optics-microstructure limits on reflectivity

    SciTech Connect

    Walton, Christopher Charles

    1997-12-01

    Multilayer thin films are used as Bragg reflectors for soft x-rays in the energy range 50eV < E < 1000eV in many x-ray optics applications such as x-ray microscopes and telescopes, reducing optics for extreme ultraviolet (EUV) lithography, and x-ray polarizers and phase retarders. Applications often depend critically on reflectivity, which has not been systematically characterized for multilayer periods below 20Å. For this study, W/B4C multilayers were fabricated by magnetron sputtering on Si(111), with periods from 48Å to as little as 4.7Å. The x-ray reflectivity measured at λ = 1.54Å and at 45° incidence (289 eV < E < 860 eV) was found to decrease sharply for multilayer periods less than 15-20Å. Examination by high-resolution transmission electron microscopy (HRTEM) showed an expansion of the thickness of the W-rich layers of 30-40% from the nominal values, consistent with intermixture of the two materials during sputter growth, and discontinuous W-rich layers for multilayer periods below about 15Å. The experimental data for the specular reflectivity in the hard and soft x-ray regimes and the diffuse scattering fit well to a model of multilayer roughness. The model is expressed as a power-law dependence of roughness on spatial frequency. Analysis of small-angle scattering in transmission from multilayers grown on freestanding Si3N4 membranes confirms the onset of discontinuity at periods between 14Å and 22Å. Spectroscopy studies by x-ray absorption (NEXAFS) and electron energy loss (EELS) at the boron K-edge (188eV) are consistent with changes in the average boron bonding environment, as the multilayer period decreases and the W-rich layers are increasingly thin and dispersed. A discrete W-rich phase is present for periods at least as small as 6.3Å.

  18. X-ray shearing interferometer

    DOEpatents

    Koch, Jeffrey A [Livermore, CA

    2003-07-08

    An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

  19. The Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

    NASA Technical Reports Server (NTRS)

    Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B. C., Jr.; Allen, Max J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C.

    1992-01-01

    We have developed seven compact soft X-ray/EUV (XUV) multilayer coated and two compact FUV interference film coated Cassegrain and Ritchey-Chretien telescopes for a rocket borne observatory, the Multi-Spectral Solar Telescope Array. We report here on extensive measurements of the efficiency and spectral bandpass of the XUV telescopes carried out at the Stanford Synchrotron Radiation Laboratory.

  20. The Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

    NASA Technical Reports Server (NTRS)

    Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B. C., Jr.; Allen, Max J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C.

    1992-01-01

    We have developed seven compact soft X-ray/EUV (XUV) multilayer coated and two compact FUV interference film coated Cassegrain and Ritchey-Chretien telescopes for a rocket borne observatory, the Multi-Spectral Solar Telescope Array. We report here on extensive measurements of the efficiency and spectral bandpass of the XUV telescopes carried out at the Stanford Synchrotron Radiation Laboratory.

  1. Joint x-ray

    MedlinePlus

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  2. Chest X Ray?

    MedlinePlus

    ... this page from the NHLBI on Twitter. Chest X Ray A chest x ray is a fast and painless imaging test that ... tissue scarring, called fibrosis. Doctors may use chest x rays to see how well certain treatments are working ...

  3. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1990-01-01

    The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

  4. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  5. Skull x-ray

    MedlinePlus

    X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... Chernecky CC, Berger BJ. Radiography of skull, chest, and cervical spine - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. ...

  6. Chest X-Ray

    MedlinePlus

    ... by Image/Video Gallery Your radiologist explains chest x-ray. Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

  7. Direct analysis of blood serum by total reflection X-ray fluorescence spectrometry and application of an artificial neural network approach for cancer diagnosis*1

    NASA Astrophysics Data System (ADS)

    Hernández-Caraballo, Edwin A.; Marcó-Parra, Lué M.

    2003-12-01

    Iron, copper, zinc and selenium were determined directly in serum samples from healthy individuals ( n=33) and cancer patients ( n=27) by total reflection X-ray fluorescence spectrometry using the Compton peak as internal standard [L.M. Marcó P. et al., Spectrochim. Acta Part B 54 (1999) 1469-1480]. The standardized concentrations of these elements were used as input data for two-layer artificial neural networks trained with the generalized delta rule in order to classify such individuals according to their health status. Various artificial neural networks, comprising a linear function in the input layer, a hyperbolic tangent function in the hidden layer and a sigmoid function in the output layer, were evaluated for such a purpose. Of the networks studied, the (4:4:1) gave the highest estimation (98%) and prediction rates (94%). The latter demonstrates the potential of the total reflection X-ray fluorescence spectrometry/artificial neural network approach in clinical chemistry.

  8. Simple method of determination of copper, mercury and lead in potable water with preliminary pre-concentration by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Hołyńska, B.; Ostachowicz, B.; Wȩgrzynek, D.

    1996-06-01

    Total reflection X-ray fluorescence spectrometry and chemical pre-concentration procedures have been applied for the analysis of trace concentrations of copper, mercury, and lead in drinking water samples. A simple total reflection module has been used in X-ray measurements. The elements under investigation were pre-concentrated by complexation using a mixture of carbamates followed by solvent extraction with methyl isobutyl ketone. The preconcentration procedure was tested with the use of twice-distilled water samples and samples of mineral and tap water spiked with known additions of copper, mercury, and lead. The obtained recovery and precision values are presented. The minimum detection limits for the determination of these elements in mineral and tap water samples were found to be 40 ng l -1, 60 ng l -1, and 60 ng l -1, respectively.

  9. A rapid total reflection X-ray fluorescence protocol for micro analyses of ion profiles in Arabidopsis thaliana

    NASA Astrophysics Data System (ADS)

    Höhner, Ricarda; Tabatabaei, Samaneh; Kunz, Hans-Henning; Fittschen, Ursula

    2016-11-01

    The ion homeostasis of macro and micronutrients in plant cells and tissues is a fundamental requirement for vital biochemical pathways including photosynthesis. In nature, ion homeostasis is affected mainly by three processes: 1. Environmental stress factors, 2. Developmental effects, and 3. Loss or gain-of-function mutations in the plant genome. Here we present a rapid total reflection X-ray fluorescence (TXRF) protocol that allows for simultaneous quantification of several elements such as potassium (K), calcium (Ca), sulfur (S), manganese (Mn) and strontium (Sr) in Arabidopsis thaliana leaf specimens. Our procedure is cost-efficient and enables precise, robust and highly reproducible measurements on tissue samples as small as 0.3 mg dry weight. As shown here, we apply the TXRF procedure to detect accurately the early replacement of K by Na ions in leaves of plants exposed to soil salinity, a globally increasing abiotic stress factor. Furthermore, we were able to prove the existence of a leaf development-dependent ion gradient for K, Ca, and other divalent ions in A. thaliana; i.e. old leaves contain significantly lower K but higher Ca than young leaves. Lastly, we show that our procedure can be readily applied to reveal subtle differences in tissue-specific ion contents of plant mutants. We employed independent A. thaliana kea1kea2 loss-of-function mutants that lack KEA1 and KEA2, two highly active chloroplast K exchange proteins. We found significantly increased K levels specifically in kea1kea2 mutants, i.e. 55 mg ∗ g- 1 dry weight, compared to 40 mg ∗ g- 1 dry weight in wild type plants. The TXRF procedure can be supplemented with Flame atomic absorption (FAAS) and emission spectrometry (FAES) to expand the detection range to sodium (Na) and magnesium (Mg). Because of the small sample amounts required, this method is especially suited to probe individual leaves in single plants or even specific leaf areas. Therefore, TXRF represents a powerful method to

  10. Exploring the interfacial structure of protein adsorbates and the kinetics of protein adsorption: an in situ high-energy X-ray reflectivity study.

    PubMed

    Evers, Florian; Shokuie, Kaveh; Paulus, Michael; Sternemann, Christian; Czeslik, Claus; Tolan, Metin

    2008-09-16

    The high energy X-ray reflectivity technique has been applied to study the interfacial structure of protein adsorbates and protein adsorption kinetics in situ. For this purpose, the adsorption of lysozyme at the hydrophilic silica-water interface has been chosen as a model system. The structure of adsorbed lysozyme layers was probed for various aqueous solution conditions. The effect of solution pH and lysozyme concentration on the interfacial structure was measured. Monolayer formation was observed for all cases except for the highest concentration. The adsorbed protein layers consist of adsorbed lysozyme molecules with side-on or end-on orientation. By means of time-dependent X-ray reflectivity scans, the time-evolution of adsorbed proteins was monitored as well. The results of this study demonstrate the capabilities of in situ X-ray reflectivity experiments on protein adsorbates. The great advantages of this method are the broad wave vector range available and the high time resolution.

  11. Kramers-Kronig analysis of soft x-ray reflectivity data of platinum thin film in 40-200 Å wavelength region

    SciTech Connect

    Sharma, Saurabh; Gupta, R. K.; Sinha, Mangalika; Singh, Amol; Yadav, P.; Modi, Mohammed H.

    2016-05-23

    Reflectivity beamline at Indus-1 synchrotron source is used to determine optical constants of a platinum thin film in the soft x-ray wavelength region of 40-200Å by applying Kramers-Kronig (KK) technique on R vs wavelength data. Upto 150Å wavelength region the results of KK analysis are found in good agreement with the Henke’s optical constants and also with those obtained by the angle dependent reflectivity technique. A significant mismatch is observed above 150Å wavelength region which could be due to the presence of higher harmonics in the toroidal grating spectra of the reflectivity beamline.

  12. Kramers-Kronig analysis of soft x-ray reflectivity data of platinum thin film in 40-200 Å wavelength region

    NASA Astrophysics Data System (ADS)

    Sharma, Saurabh; Gupta, R. K.; Sinha, Mangalika; Yadav, P.; Singh, Amol; Modi, Mohammed H.

    2016-05-01

    Reflectivity beamline at Indus-1 synchrotron source is used to determine optical constants of a platinum thin film in the soft x-ray wavelength region of 40-200Å by applying Kramers-Kronig (KK) technique on R vs wavelength data. Upto 150Å wavelength region the results of KK analysis are found in good agreement with the Henke's optical constants and also with those obtained by the angle dependent reflectivity technique. A significant mismatch is observed above 150Å wavelength region which could be due to the presence of higher harmonics in the toroidal grating spectra of the reflectivity beamline.

  13. Center for X-ray Optics, 1988

    SciTech Connect

    Not Available

    1989-04-01

    This report briefly reviews the following topics: soft-x-ray imaging; reflective optics for hard x-rays; coherent XUV sources; spectroscopy with x-rays; detectors for coronary artery imaging; synchrotron-radiation optics; and support for the advanced light source.

  14. Fluorescence-based knife-edge beam diameter measurement to characterize X-ray beam profiles in reflection geometry

    NASA Astrophysics Data System (ADS)

    Bassel, Léna; Tauzin, Xavier; Queffelec, Alain; Ferrier, Catherine; Lacanette, Delphine; Chapoulie, Rémy; Bousquet, Bruno

    2016-04-01

    The diameter of an X-ray beam was determined, using the knife-edge technique, widely applied for beam profiling, by taking advantage of the fluorescence emission generated by the X-ray beam. The knife-edge has to be appropriate to the configuration of the device, in our case a double-material target made of plastic and cardboard was scanned in a transversal plane compared to the beam propagation direction. Along the scanning axis, for each position, the intensity of the Kα line of chlorine was recorded. The first derivative of the intensity evolution as a function of the edge position, fitted by a Gaussian function, makes it possible to obtain the beam diameter along the scan direction. We measured a slightly elliptic diameter close to 3 mm. In this note we underline the significance of the knife-edge technique which represents a useful tool, easy to be set up, to control X-ray beam dimensions in portable devices often routinely used by non-specialists.

  15. The condensation of the corona for the correlation between the hard X-ray photon index Γ and the reflection scaling factor ℜ in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin; Liu, B. F.

    2017-05-01

    Observationally, it is found that there is a strong correlation between the hard X-ray photon index Γ and the Compton reflection scaling factor ℜ in active galactic nuclei. In this paper, we propose that the Γ - ℜ correlation can be explained within the framework of the condensation of the hot corona on to the cold accretion disc around a supermassive black hole. In the model, it is presumed that, initially, a vertically extended hot gas (corona) is supplied to the central supermassive black hole by capturing the interstellar medium and stellar wind. In this scenario, when the initial mass accretion rate \\dot{M}/ \\dot{M}_Edd ≳ 0.01, at a critical radius rd, part of the hot gas begins to condense on to the equatorial disc plane of the black hole, forming an inner cold accretion disc. Then, the matter is accreted in the form of a disc-corona structure extending down to the innermost stable circular orbits of the black hole. The size of the inner disc is determined by the initial mass accretion rate. With the increase of the initial mass accretion rate, the size of the inner disc increases, which results in both the increase of the Compton reflection scaling factor ℜ and the increase of the hard X-ray photon index Γ. By comparing with a sample of Seyfert galaxies with well-fitted X-ray spectra, it is found that our model can roughly explain the observations. Finally, we discuss the possibility of applying our model to high-mass X-ray binaries, which are believed to be fuelled by hot winds from the companion stars.

  16. The condensation of the corona for the correlation between the hard X-ray photon index Γ and the reflection scaling factor ℜ in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin; Liu, B. F.

    2017-01-01

    Observationally, it is found that there is a strong correlation between the hard X-ray photon index Γ and the Compton reflection scaling factor ℜ in active galactic nuclei. In this paper, we propose that the Γ - ℜ correlation can be explained within the framework of the condensation of the hot corona onto the cold accretion disc around a supermassive black hole. In the model, it is presumed that, initially, a vertically extended hot gas (corona) is supplied to the central supermassive black hole by capturing the interstellar medium and stellar wind. In this scenario, when the initial mass accretion rate dot{M}/ dot{M}_Edd gtrsim 0.01, at a critical radius rd, part of the hot gas begins to condense onto the equatorial disc plane of the black hole, forming an inner cold accretion disc. Then the matter is accreted in the form of the disc-corona structure extending down to the innermost stable circular orbits of the black hole. The size of the inner disc is determined by the initial mass accretion rate. With the increase of the initial mass accretion rate, the size of the inner disc increases, which results in both the increase of the Compton reflection scaling factor ℜ and the increase of the hard X-ray photon index Γ. By comparing with a sample of Seyfert galaxies with well-fitted X-ray spectra, it is found that our model can roughly explain the observations. Finally, we discuss the possibility to apply our model to high mass X-ray binaries, which are believed to be fueled by the hot wind from the companion star.

  17. Chest x-ray

    MedlinePlus

    Chest radiography; Serial chest x-ray; X-ray - chest ... You stand in front of the x-ray machine. You will be told to hold your breath when the x-ray is taken. Two images are usually taken. You will ...

  18. Reflection Grating Array Associated with the Reflection Grating Spectrometer Developed by the Space Research Organization of the Netherlands for the X-ray Multi-Mirror Mission (XMM)

    NASA Technical Reports Server (NTRS)

    Kahn, Steven M.

    2001-01-01

    The University of California, Berkeley (UCB) served as the Principal Investigator institution for the United States participation in the development of the Reflection Grating Spectrometer (RGS) which included the design, development, fabrication, and testing of the Reflection Grating Assembly (RGA). UCB was assisted in this role by the Lawrence Livermore National Laboratory and Columbia University who provided the primary facilities, materials, services and personnel necessary to complete the development. UC Berkeley's Dr. Steven Kahn provided the technical and scientific oversight for the design. development and testing of the RGA units by monitoring the performance of the units at various stages in their development. Dr. Kahn was also the primary contact with the Space Research Organization of the Netherlands (SRON) and represented the RGA development at all SRON and European Space Agency (ESA) reviews of the RGA status. In accordance with the contract, the team designed and developed novel optical technology to meet the unique requirements of the RGS. The ESA XMM-Newton Mission carries two identical Reflection Grating Spectrometers (RGS) behind two of its three nested sets of Wolter I type mirrors. The instrument allows high-resolution measurements in the soft X-ray range (6 to 38 angstroms or 2.1 to 0.3 keV) with a maximum effective area of about 140 sq cm at 15 angstroms. Its design is optimized for the detection of the K-shell transitions of carbon, nitrogen, oxygen, neon, magnesium, and silicon. as well as the L shell transitions of iron. The RGA itself consists of two units. A structure for each unit was designed to hold up to 220 gratings. In its final configuration, one unit holds 182 gratings and the second hold 181 gratings.

  19. NUSTAR and SUZAKU X-ray spectroscopy of NGC 4151: Evidence for reflection from the inner accretion disk

    SciTech Connect

    Keck, M. L.; Brenneman, L. W.; Ballantyne, D. R.; Bauer, F.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Dauser, T.; Elvis, M.; Fabian, A. C.; Fuerst, F.; García, J.; Grefenstette, B. W.; Hailey, C. J.; Harrison, F. A.; Madejski, G.; Marinucci, A.; Matt, G.; Reynolds, C. S.; Stern, D.; Walton, D. J.; Zoghbi, A.

    2015-06-15

    We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spin $a\\gt 0.9$ accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection (IDR) flux variation drives the spectral variability during the observations. As a result, we discuss various physical scenarios for the IDR model and we find that a compact corona is consistent with the observed features.

  20. X ray imaging microscope for cancer research

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

    1991-01-01

    The NASA technology employed during the Stanford MSFC LLNL Rocket X Ray Spectroheliograph flight established that doubly reflecting, normal incidence multilayer optics can be designed, fabricated, and used for high resolution x ray imaging of the Sun. Technology developed as part of the MSFC X Ray Microscope program, showed that high quality, high resolution multilayer x ray imaging microscopes are feasible. Using technology developed at Stanford University and at the DOE Lawrence Livermore National Laboratory (LLNL), Troy W. Barbee, Jr. has fabricated multilayer coatings with near theoretical reflectivities and perfect bandpass matching for a new rocket borne solar observatory, the Multi-Spectral Solar Telescope Array (MSSTA). Advanced Flow Polishing has provided multilayer mirror substrates with sub-angstrom (rms) smoothnesss for the astronomical x ray telescopes and x ray microscopes. The combination of these important technological advancements has paved the way for the development of a Water Window Imaging X Ray Microscope for cancer research.

  1. Elemental analysis of human amniotic fluid and placenta by total-reflection X-ray fluorescence and energy-dispersive X-ray fluorescence: child weight and maternal age dependence

    NASA Astrophysics Data System (ADS)

    Carvalho, M. L.; Custódio, P. J.; Reus, U.; Prange, A.

    2001-11-01

    This work is an attempt to evaluate the possible influence of the mother's age in trace element concentrations in human amniotic fluid and placenta and whether these concentrations are correlated to the weight of the newborn infants. Total-reflection X-ray fluorescence (TXRF) was used to analyze 16 amniotic fluid samples, and the placenta samples were analyzed by energy dispersive X-ray fluorescence (EDXRF). The whole samples were collected during delivery from healthy mothers and healthy infants and full-term pregnancies. According to the age of the mother, three different groups were considered: 20-25, 25-30 and 30-40 years old. Only two mothers were aged more than 35 years. The weight of the infants ranged from 2.56 to 4.05 kg and three groups were also considered: 2.5-3, 3-3.5 and 3.5-4 kg. The organic matrix of the amniotic fluid samples was removed by treatment with HNO 3 followed by oxygen plasma ashing. Yttrium was used as the internal standard for TXRF analysis. Placenta samples were lyophilized and analyzed by EDXRF without any chemical treatment. Very low levels of Ni and Sr were found in the amniotic fluid samples, and were independent of the age of the mother and weight of the child. Cr, Mn, Se and Pb were at the level of the detection limit. Zn, considered one of the key elements in neonatal health, was not significantly different in the samples analyzed; however, it was weakly related to birth weigh. The concentrations obtained ranged from 0.11 to 0.92 mg/l and 30 to 65 μg/g in amniotic fluid and placenta, respectively. The only two elements which seemed to be significantly correlated with mother's age and newborn weight were Ca and Fe for both types of sample: Ca levels were increased in heavier children and older mothers; however, Fe increased with increasing maternal age, but decreased for heavier babies. The same conclusions were obtained for placenta and amniotic fluid samples. Cu is closely associated with Fe in its function in the organism

  2. Observation of surface reduction of NiO to Ni by surface-sensitive total reflection X-ray spectroscopy using Kramers-Kronig relations

    NASA Astrophysics Data System (ADS)

    Abe, Hitoshi; Nakayama, Takeshi; Niwa, Yasuhiro; Nitani, Hiroaki; Kondoh, Hiroshi; Nomura, Masaharu

    2016-06-01

    We have developed a promising surface-sensitive X-ray absorption fine structure (XAFS) measurement method. This method is based on total reflection detection and Kramers-Kronig relations, and has been named the KK-XAFS method. Total reflection spectra are transformed via Kramers-Kronig relations to obtain XAFS spectra. KK-XAFS experiments give us surface-sensitive structural parameters, while usual EXAFS analyses yield bulk structural parameters. The total reflection spectra themselves are useful for observing and discussing time evolutions of chemical reactions at surfaces by quick scanning measurements. Chemical species are analyzed to estimate their fractions during reactions. The whole method would be named total reflection X-ray spectroscopy (TREXS). A reduction of the NiO layer at the surface of Ni (30 nm)/Si was observed in a laboratory-built TREXS in situ cell. The method would be applicable to observe chemical reactions starting at surfaces and to study their kinetics and mechanisms.

  3. Thoracic spine x-ray

    MedlinePlus

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

  4. NuSTAR and Swift joint view of neutron star X-ray binary 4U 1728-34: disc reflection in the island and lower banana states

    NASA Astrophysics Data System (ADS)

    Mondal, Aditya S.; Pahari, Mayukh; Dewangan, G. C.; Misra, R.; Raychaudhuri, B.

    2017-04-01

    We analyse two simultaneous NuSTAR and Swift data of the Atoll-type neutron star (NS) X-ray binary 4U 1728-34 observed on 2013 October 1 and 3. We infer that the first and the second observations belong to the island state and the lower banana state, respectively. During island state, four type-I X-ray bursts are observed within 60 ks exposure. From the time-resolved spectral analysis of each burst with NuSTAR, the blackbody temperature kTbb are found to vary between 1.3 and 3.0 keV, while the blackbody normalizations (km/10 kpc)2 vary in the range 20-200, which translates to blackbody radii of 3.5-7.4 km for an assumed distance of 5 kpc. The persistent, joint energy spectra from Swift and NuSTAR for both observations in the energy band 1-79 keV are well described with thermal emission from the NS surface (kTbb ≃ 1-2.5 keV), Comptonized emission of thermal seed photons from the hot boundary layer/corona and the strong reflection component from the accretion disc. We detect a broad iron line in the 5-8 keV band and reflection hump in the 15-30 keV band modelled by the relxill reflection model. Joint spectral fitting constrains the inclination angle of the binary system and inner disc radius to be 22°-40° and (2.0-4.3) × RISCO, respectively. We estimate the magnetic field to be (1.8-6.5) × 108 G. The X-ray luminosity of the source during the island and lower banana states are found to be LX = 1.1 and 1.6 × 1037 erg s-1, respectively, which correspond to ˜6 per cent and ˜9 per cent of the Eddington luminosity.

  5. NuSTAR and SWIFT joint view of neutron star X-ray binary 4U 1728-34 : Disc reflection in the island and lower banana states

    NASA Astrophysics Data System (ADS)

    Mondal, Aditya S.; Pahari, Mayukh; Dewangan, G. C.; Misra, R.; Raychaudhuri, B.

    2017-01-01

    We analyze two simultaneous NuSTAR and SWIFT data of the Atoll type neutron star (NS) X-ray binary 4U 1728-34 observed on 1 and 3 October, 2013. We infer that the first and the second observations belong to the island state and the lower banana state respectively. During island state, four type-I X-ray bursts are observed within 60 ks exposure. From the time-resolved spectral analysis of each burst with NuSTAR, the blackbody temperature kTbb are found to vary between 1.3 to 3.0 keV while the blackbody normalizations (km/10 kpc)2 vary in the range 20 to 200, which translates to blackbody radii of 3.5 - 7.4 km for an assumed distance of 5 kpc. The persistent, joint energy spectra from SWIFT and NuSTAR for both observations in the energy band 1 - 79 keV are well described with thermal emission from the NS surface (kTbb ≃ 1 - 2.5 keV), Comptonized emission of thermal seed photons from the hot boundary layer/corona and the strong reflection component from the accretion disc. We detect a broad Iron line in the 5 - 8 keV band and reflection hump in the 15 - 30 keV band modelled by the relxill reflection model. Joint spectral fitting constrains the inclination angle of the binary system and inner disc radius to be 22 - 40 and (2.0 - 4.3) × RISCO, respectively. We estimate the magnetic field to be (1.8 - 6.5) × 108 Gauss. The X-ray luminosity of the source during the island and lower banana states are found to be LX = 1.1 and 1.6 × 1037 erg s-1 respectively which correspond to ˜6% and ˜9% of the Eddington luminosity.

  6. Carbon contamination of soft X-ray beamlines: dramatic anti-reflection coating effects observed in the 1 keV photon energy region.

    PubMed

    Chauvet, C; Polack, F; Silly, M G; Lagarde, B; Thomasset, M; Kubsky, S; Duval, J P; Risterucci, P; Pilette, B; Yao, I; Bergeard, N; Sirotti, F

    2011-09-01

    Carbon contamination is a general problem of under-vacuum optics submitted to high fluence. In soft X-ray beamlines carbon deposit on optics is known to absorb and scatter radiation close to the C K-edge (280 eV), forbidding effective measurements in this spectral region. Here the observation of strong reflectivity losses is reported related to carbon deposition at much higher energies around 1000 eV, where carbon absorptivity is small. It is shown that the observed effect can be modelled as a destructive interference from a homogeneous carbon thin film.

  7. Application of the total reflection X-ray fluorescence method to the elemental analysis of brain tumors of different types and grades of malignancy

    NASA Astrophysics Data System (ADS)

    Lankosz, M. W.; Grzelak, M.; Ostachowicz, B.; Wandzilak, A.; Szczerbowska-Boruchowska, M.; Wrobel, P.; Radwanska, E.; Adamek, D.

    2014-11-01

    The process of carcinogenesis may influence normal biochemical reactions leading to alterations in the elemental composition of the tissue. Total reflection X-ray fluorescence analysis (TXRF) was applied to the elemental analysis of different brain tumors. The following elements were present in all the neoplastic tissues analyzed: K, Ca, Fe, Cu, Zn and Rb. The results of the analysis showed that the elemental composition of a relatively small fragment of tissue represents satisfactorily the biochemical “signature” of a cancer. On the basis of the element concentrations determined, it was possible to differentiate between some types of brain tumors.

  8. Determination of ultra trace contaminants on silicon wafer surfaces using total-reflection X-ray fluorescence TXRF 'state-of-the-art'

    NASA Astrophysics Data System (ADS)

    Pahlke, S.; Fabry, L.; Kotz, L.; Mantler, C.; Ehmann, T.

    2001-11-01

    In a well balanced system of highly motivated, well trained personnel and automated equipment, pure reagents and bulk media, cleanrooms and integrated data management, total-reflection X-ray fluorescence (TXRF) can and must contribute to quality assurance and process stability, support and canalize creative engineering by continuous learning about materials and processes. TXRF has the advantage of controlled one-point calibration, a linear dynamic range of three orders of magnitude, high grade of automation in operation and data management, high up-time, and a simple control of data plausibility.

  9. Ionic multilayers at the free surface of an ionic liquid, trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide, probed by x-ray reflectivity measurements

    NASA Astrophysics Data System (ADS)

    Nishi, Naoya; Yasui, Yukinori; Uruga, Tomoya; Tanida, Hajime; Yamada, Tasuku; Nakayama, Shun-ichi; Matsuoka, Hideki; Kakiuchi, Takashi

    2010-04-01

    The presence of ionic multilayers at the free surface of an ionic liquid, trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide ([TOMA+][C4C4N-]), extending into the bulk from the surface to the depth of ˜60 Å has been probed by x-ray reflectivity measurements. The reflectivity versus momentum transfer (Q) plot shows a broad peak at Q ˜0.4 Å-1, implying the presence of ionic layers at the [TOMA+][C4C4N-] surface. The analysis using model fittings revealed that at least four layers are formed with the interlayer distance of 16 Å. TOMA+ and C4C4N- are suggested not to be segregated as alternating cationic and anionic layers at the [TOMA+][C4C4N-] surface. It is likely that the detection of the ionic multilayers with x-ray reflectivity has been realized by virtue of the greater size of TOMA+ and C4C4N- and the high critical temperature of [TOMA+][C4C4N-].

  10. Microstructure and composition analysis of low-Z/low-Z multilayers by combining hard and resonant soft X-ray reflectivity

    SciTech Connect

    Rao, P. N. Rai, S. K.; Srivastava, A. K.; Ganguli, T.; Naik, P. A.; Dhawan, R.

    2016-06-28

    Microstructure and composition analysis of periodic multilayer structure consisting of a low electron density contrast (EDC) material combination by grazing incidence hard X-ray reflectivity (GIXR), resonant soft X-ray reflectivity (RSXR), and transmission electron microscopy (TEM) are presented. Measurements of reflectivity at different energies allow combining the sensitivity of GIXR data to microstructural parameters like layer thicknesses and interfacing roughness, with the layer composition sensitivity of RSXR. These aspects are shown with an example of 10-period C/B{sub 4}C multilayer. TEM observation reveals that interfaces C on B{sub 4}C and B{sub 4}C on C are symmetric. Although GIXR provides limited structural information when EDC between layers is low, measurements using a scattering technique like GIXR with a microscopic technique like TEM improve the microstructural information of low EDC combination. The optical constants of buried layers have been derived by RSXR. The derived optical constants from the measured RSXR data suggested the presence of excess carbon into the boron carbide layer.

  11. Hygrothermal degradation of (3-glycidoxypropyl)trimethoxysilane films studied by neutron and X-ray reflectivity and attenuated total reflection infrared spectroscopy.

    PubMed

    Yim, H; Kent, M S; Tallant, D R; Garcia, M J; Majewski, J

    2005-05-10

    Thin films of organosilanes have great technological importance in the areas of adhesion promotion, durability, and corrosion resistance. However, it is well-known that water can degrade organosilane films, particularly at elevated temperatures. In this work, X-ray and neutron reflectivity (XR and NR) were combined with attenuated total reflection infrared (ATR-IR) spectroscopy to study the chemical and structural changes within thin films of (3-glycidoxypropyl)trimethoxysilane (GPS) after exposure for various periods of time to air saturated with either D2O or H2O at 80 degrees C. For NR and XR, ultrathin (approximately 100 A) films were prepared by spin-coating. Both D2O and H2O provide neutron scattering contrast with GPS. Variations in the neutron scattering length density (SLD) profiles (a function of mass density and atomic composition) with conditioning time were measured after drying the samples out and also swelled with H2O or D2O vapor at room temperature. For samples that were dried out prior to measurement, little or no change was observed for H2O conditioning up to 3.5 days, but large changes were observed after 30 days of conditioning. The range of conditioning time for this structural change was narrowed to between 4 and 10 days with XR. The SLD profiles indicated that the top portion of the GPS film was transformed into a thick low-density layer after conditioning, but the bottom portion showed little structural change. A previous NR study of as-prepared GPS films involving swelling with deuterated nitrobenzene showed that the central portion of the film has much lower cross-link density than the region nearest the substrate. The present data show that the central portion also swells to a much greater extent with water and hydrolyzes more rapidly. The chemical degradation mechanism was identified by IR as hydrolysis of siloxane bonds. For ATR-IR, GPS films were prepared by dip-coating, which resulted in a greater and more variable thickness than for

  12. Rb+ adsorption at the quartz(101)-aqueous interface: comparison of resonant anomalous x-ray reflectivity with ab initio calculations

    SciTech Connect

    Bellucci, Francesco; Lee, Sang Soo; Kubicki, James D.; Bandura, Andrei V.; Zhang, Zhan; Wesolowski, David J.; Fenter, Paul

    2015-01-29

    We study adsorption of Rb+ to the quartz(101)–aqueous interface at room temperature with specular X-ray reflectivity, resonant anomalous X-ray reflectivity, and density functional theory. The interfacial water structures observed in deionized water and 10 mM RbCl solution at pH 9.8 were similar, having a first water layer at height of 1.7 ± 0.1 Å above the quartz surface and a second layer at 4.8 ± 0.1 Å and 3.9 ± 0.8 Å for the water and RbCl solutions, respectively. The adsorbed Rb+ distribution is broad and consists of presumed inner-sphere (IS) and outer-sphere (OS) complexes at heights of 1.8 ± 0.1 and 6.4 ± 1.0 Å, respectively. Projector-augmented planewave density functional theory (DFT) calculations of potential configurations for neutral and negatively charged quartz(101) surfaces at pH 7 and 12, respectively, reveal a water structure in agreement with experimental results. These DFT calculations also show differences in adsorbed speciation of Rb+ between these two conditions. At pH 7, the lowest energy structure shows that Rb+ adsorbs dominantly as an IS complex, whereas at pH 12 IS and OS complexes have equivalent energies. The DFT results at pH 12 are generally consistent with the two site Rb distribution observed from the X-ray data at pH 9.8, albeit with some differences that are discussed. In conclusion, surface charge estimated on the basis of the measured total Rb+ coverage was -0.11 C/m2, in good agreement with the range of the surface charge magnitudes reported in the literature.

  13. Bone x-ray

    MedlinePlus

    ... not being scanned. Alternative Names X-ray - bone Images Skeleton Skeletal spine Osteogenic sarcoma - x-ray References ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  14. Dental x-rays

    MedlinePlus

    X-ray - teeth; Radiograph - dental; Bitewings; Periapical film; Panoramic film; Digital image ... dentist's office. There are many types of dental x-rays. Some of them are: Bitewing. Shows the crown ...

  15. X-ray (image)

    MedlinePlus

    X-rays are a form of ionizing radiation that can penetrate the body to form an image on ... will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other ...

  16. X-Ray Lasers

    ERIC Educational Resources Information Center

    Chapline, George; Wood, Lowell

    1975-01-01

    Outlines the prospects of generating coherent x rays using high-power lasers and indentifies problem areas in their development. Indicates possible applications for coherent x rays in the fields of chemistry, biology, and crystallography. (GS)

  17. X-ray

    MedlinePlus

    ... image. For most x-rays, the risk of cancer or defects is very low. Most experts feel that the benefits of appropriate x-ray ... Geleijns J, Tack D. Medical physics: radiation risks. In: Adam A, Dixon AK, Gillard ...

  18. X-Ray Toolkit

    SciTech Connect

    2015-10-20

    Radiographic Image Acquisition & Processing Software for Security Markets. Used in operation of commercial x-ray scanners and manipulation of x-ray images for emergency responders including State, Local, Federal, and US Military bomb technicians and analysts.

  19. Sinus x-ray

    MedlinePlus

    Paranasal sinus radiography; X-ray - sinuses ... sinus x-ray is taken in a hospital radiology department. Or the x-ray may be taken ... Brown J, Rout J. ENT, neck, and dental radiology. In: Adam A, Dixon AK, Gillard JH Schaefer- ...

  20. Hand x-ray

    MedlinePlus

    X-ray - hand ... A hand x-ray is taken in a hospital radiology department or your health care provider's office by an ... technician. You will be asked to place your hand on the x-ray table, and keep it ...

  1. Chain-length dependent growth dynamics of n-alkanes on silica investigated by energy-dispersive x-ray reflectivity in situ and in real-time

    NASA Astrophysics Data System (ADS)

    Weber, C.; Frank, C.; Bommel, S.; Rukat, T.; Leitenberger, W.; Schäfer, P.; Schreiber, F.; Kowarik, S.

    2012-05-01

    We compare the growth dynamics of the three n-alkanes C36H74, C40H82, and C44H90 on SiO2 using real-time and in situ energy-dispersive x-ray reflectivity. All molecules investigated align in an upright-standing orientation on the substrate and exhibit a transition from layer-by-layer growth to island growth after about 4 monolayers under the conditions employed. Simultaneous fits of the reflected intensity at five distinct points in reciprocal space show that films formed by longer n-alkanes roughen faster during growth. This behavior can be explained by a chain-length dependent height of the Ehrlich-Schwoebel barrier. Further x-ray diffraction measurements after growth indicate that films consisting of longer n-alkanes also incorporate more lying-down molecules in the top region. While the results reveal behavior typical for chain-like molecules, the findings can also be useful for the optimization of organic field effect transistors where smooth interlayers of n-alkanes without coexistence of two or more molecular orientations are required.

  2. Simultaneous study of mechanical property development and early hydration chemistry in Portland cement slurries using X-ray diffraction and ultrasound reflection

    SciTech Connect

    Jupe, Andrew C.; Wilkinson, Angus P.; Funkhouser, Gary P.

    2012-10-25

    A sample cell for the simultaneous measurement of synchrotron X-ray powder diffraction and ultrasound shear-wave reflection data from cement slurries is described. White cement slurries at 25 and 50 C with 0-3% bwoc CaCl{sub 2} were studied to illustrate the potential of the apparatus. The decrease in reflected S-wave amplitude, in dB, showed a linear correlation with C{sub 3}S hydration. CaCl{sub 2} retarded the development of G{prime} and G{double_prime} relative to the extent of C{sub 3}S hydration. At short times, there was a correlation between the time evolution of both G{prime} and G{double_prime}, and the amount of precipitated CH seen by diffraction, which was almost independent of CaCl{sub 2} concentration and temperature. CaCl{sub 2} addition resulted in a decrease in the amount of CH visible to X-rays, relative the degree of C{sub 3}S hydration. This may indicate a change in C-S-H gel C:S ratio or the presence of nanoscale CH that could not be seen by diffraction.

  3. Nearly Anastigmatic X-Ray Telescope

    NASA Technical Reports Server (NTRS)

    Korsch, D.

    1985-01-01

    Proposed X-ray telescope made of many concentric reflecting rings, each of which consists of two portions of cone. Proposed design is variation on conventional grazing incidence X-ray telescope, which has just one twosegment reflecting element but suffers from excessive astigmatism and field curvature. Using many short elements instead of single long element, new design gives nearly anastigmatic image.

  4. X-ray lithography using holographic images

    DOEpatents

    Howells, Malcolm R.; Jacobsen, Chris

    1995-01-01

    A non-contact X-ray projection lithography method for producing a desired X-ray image on a selected surface of an X-ray-sensitive material, such as photoresist material on a wafer, the desired X-ray image having image minimum linewidths as small as 0.063 .mu.m, or even smaller. A hologram and its position are determined that will produce the desired image on the selected surface when the hologram is irradiated with X-rays from a suitably monochromatic X-ray source of a selected wavelength .lambda.. On-axis X-ray transmission through, or off-axis X-ray reflection from, a hologram may be used here, with very different requirements for monochromaticity, flux and brightness of the X-ray source. For reasonable penetration of photoresist materials by X-rays produced by the X-ray source, the wavelength X, is preferably chosen to be no more than 13.5 nm in one embodiment and more preferably is chosen in the range 1-5 nm in the other embodiment. A lower limit on linewidth is set by the linewidth of available microstructure writing devices, such as an electron beam.

  5. Wide field x-ray telescopes: Detecting x-ray transients/afterglows related to GRBs

    SciTech Connect

    Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul

    1998-05-16

    The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited fields of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70's but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster-eye type are presented and discussed. The optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed.

  6. Characterization of a chiral phase in an achiral bent-core liquid crystal by polarization studies of resonant x-ray forbidden reflections

    NASA Astrophysics Data System (ADS)

    Ponsinet, V.; Barois, P.; Pan, Lidong; Wang, Shun; Huang, C. C.; Wang, S. T.; Pindak, R.; Baumeister, U.; Weissflog, W.

    2011-07-01

    The chiral antiferroelectric structure of an achiral bent-core liquid crystal is characterized by resonant x-ray scattering at chlorine K edge. The “forbidden” reflections resulting from the glide or screw symmetry elements are restored by the anisotropy of the tensor structure factor, which we calculate for two possible structural models. A careful analysis of the polarization states of the restored “forbidden” reflections enables an unambiguous identification of a chiral structure (i.e., the so-called anticlinic, antiferroelectric smectic-C or Sm-CAPA) coexisting with the achiral synclinic antiferroelectric smectic-C or Sm-CSPA. The method proves to be quite powerful as it identifies the chiral structure within coexisting phases despite an imperfect orientation of the sample. The volume fraction of the chiral phase and the distribution of alignment are extracted from the data.

  7. Chemical state analysis of trace-level alkali metals sorbed in micaceous oxide by total reflection X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Baba, Y.; Shimoyama, I.; Hirao, N.

    2016-10-01

    In order to determine the chemical states of radioactive cesium (137Cs or 134Cs) sorbed in clay minerals, chemical states of cesium as well as the other alkali metals (sodium and rubidium) sorbed in micaceous oxides have been investigated by X-ray photoelectron spectroscopy (XPS). Since the number of atoms in radioactive cesium is extremely small, we specially focused on chemical states of trace-level alkali metals. For this purpose, we have measured XPS under X-ray total reflection (TR) condition. For cesium, it was shown that ultra-trace amount of cesium down to about 100 pg cm-2 can be detected by TR-XPS. This amount corresponds to about 200 Bq of 137Cs (t1/2 = 30.2 y). It was demonstrated that ultra-trace amount of cesium corresponding to radioactive cesium level can be measured by TR-XPS. As to the chemical states, it was found that core-level binding energy in TR-XPS for trace-level cesium shifted to lower-energy side compared with that for thicker layer. A reverse tendency is observed in sodium. Based on charge transfer within a simple point-charge model, it is concluded that chemical bond between alkali metal and micaceous oxide for ultra-thin layer is more polarized that for thick layer.

  8. Can the cosmic x ray and gamma ray background be due to reflection of a steep power law spectrum and Compton scattering by relativistic electrons?

    NASA Technical Reports Server (NTRS)

    Zycki, Piotr T.; Zdziarski, Andrzej A.; Svensson, Roland

    1991-01-01

    We reconsider the recent model for the origin in the cosmic X-ray and gamma-ray background by Rogers and Field. The background in the model is due to an unresolved population of AGNs. An individual AGN spectrum contains three components: a power law with the energy index of alpha = 1.1, an enhanced reflection component, and a component from Compton scattering by relativistic electrons with a low energy cutoff at some minimum Lorentz factor, gamma(sub min) much greater than 1. The MeV bump seen in the gamma-ray background is then explained by inverse Compton emission by the electrons. We show that the model does not reproduce the shape of the observed X-ray and gamma-ray background below 10 MeV and that it overproduces the background at larger energies. Furthermore, we find the assumptions made for the Compton component to be physically inconsistent. Relaxing the inconsistent assumptions leads to model spectra even more different from that of the observed cosmic background. Thus, we can reject the hypothesis that the high-energy cosmic background is due to the described model.

  9. Elemental changes in hemolymph and urine of Rhodnius prolixus induced by in-vivo exposure to mercury: A study using synchrotron radiation total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Mantuano, Andrea; Pickler, Arissa; Barroso, Regina C.; de Almeida, André P.; Braz, Delson; Cardoso, Simone C.; Gonzalez, Marcelo S.; Figueiredo, Marcela B.; Garcia, Eloi S.; Azambuja, Patricia

    2012-05-01

    In recent years, the effects of pollution on the health of humans and other vertebrates were extensively studied. However, the effects on some invertebrates are comparatively unknown. Recent studies have demonstrated that toxic metals interfere with the reproduction, development and immune defenses of some terrestrial and marine invertebrates. Some environmental conditions including pollution produce chronic and acute effects on different animal's organs and systems. In this work, we investigated changes in the concentrations of Cl, K, Ca, Fe and Zn in Rhodnius prolixus as insect model. The elements were quantified using urine and hemolymph samples collected on different days after feeding the insects with blood containing HgCl2. The synchrotron radiation total reflection X-ray fluorescence measurements were carried at the X-ray fluorescence beamline facility in Brazilian Synchrotron Light Laboratory. The observation reveals that the calcium level was higher in the hemolymph than in urine. On the other hand, the urine collected from insects treated with HgCl2 showed higher level of Cl than hemolymph samples. Ca, Fe and Zn concentrations decrease drastically in urine samples collected after 2 days of HgCl2 treatment. The regulation of triatomines excretion was discussed pointing out the importance of trace elements.

  10. A NuSTAR Observation of the Reflection Spectrum of the Low-Mass X-Ray Binary 4U 1728-34

    NASA Technical Reports Server (NTRS)

    Sleator, Clio C.; Tomsick, John A.; King, Ashley L.; Miller, Jon M.; Boggs, Steven E.; Bachetti, Matteo; Barret, Didier; Chenevez, Jerome; Christensen, Finn E.; Craig, William W.; hide

    2016-01-01

    We report on a simultaneous NuSTAR and Swift observation of the neutron star low-mass X-ray binary 4U 1728-34. We identified and removed four Type I X-ray bursts during the observation in order to study the persistent emission. The continuum spectrum is hard and described well by a blackbody with kT=1.5 keV and a cutoff power law with Lambda = 1.5, and a cutoff temperature of 25 keV. Residuals between 6 and 8 keV provide strong evidence of a broad Fe K(alpha) line. By modeling the spectrum with a relativistically blurred reflection model, we find an upper limit for the inner disk radius of R(sub in) < or = 2R(sub ISCO). Consequently, we find that R(sub NS) < or = 23 km, assuming M = 1.4 Stellar Mass and a = 0.15. We also find an upper limit on the magnetic field of B < or =2 x 10(exp 8) G.

  11. Innovative analytical methodology combining micro-x-ray diffraction, scanning electron microscopy-based mineral maps, and diffuse reflectance infrared fourier transform spectroscopy to characterize archeological artifacts.

    PubMed

    Cardell, Carolina; Guerra, Isabel; Romero-Pastor, Julia; Cultrone, Giuseppe; Rodriguez-Navarro, Alejandro

    2009-01-15

    Excavations at the 14th century Moorish rampart (Granada, Spain) unearthed a brick oven alongside black ash and bone stratigraphic layers. In situ evidence suggests the oven served to fabricate a wall coating including powdered burnt bones. Original ad hoc analyses improved on conventional methods were used to confirm this hypothesis. These methods enable (i) nondestructive micro-X-ray diffraction (mu-XRD) for fast mineralogical data acquisition (approximately 10 s) and moderately high spatial (approximately 500 microm) resolution and (ii) identification and imaging of crystalline components in sample cross-sections via mineral maps, yielding outstanding visualization of grain distribution and morphology in composite samples based on scanning electron microscopy-energy dispersion X-ray spectrometry (SEM-EDX) elemental maps. Benefits are shown for applying diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) vs transmittance-FT-IR (T-FT-IR) to analyze organic and inorganic components in single samples. Complementary techniques to fully characterize artifacts were gas chromatography/mass spectroscopy (GC/MS), optical microscopy (OM), conventional powder XRD, and (14)C dating. Bone-hydroxyapatite was detected in the coating. Mineralogical transformations in the bricks indicate oven temperatures well above 1000 degrees C, supporting the hypothesis.

  12. Monitoring of the environmental pollution by trace element analysis in tree-rings using synchrotron radiation total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    de Vives, Ana Elisa Sirito; Moreira, Silvana; Brienza, Sandra Maria Boscolo; Medeiros, Jean Gabriel Silva; Filho, Mário Tomazello; Zucchi, Orghêda Luíza Araújo Domingues; Filho, Virgílio Franco do Nascimento

    2006-11-01

    This paper aims to study the environmental pollution in the tree development, in order to evaluate its use as bioindicator in urban and country sides. The sample collection was carried out in Piracicaba city, São Paulo State, which presents high level of environmental contamination in water, soil and air, due to industrial activities, vehicles combustion, sugar-cane leaves burning in the harvesting, etc. The species Caesalpinia peltophoroides ("Sibipiruna") was selected because it is widely used in urban forestation. Synchrotron Radiation Total Reflection X-ray Fluorescence technique (SR-TXRF) was employed to identify and quantify the elements and metals of nutritional and toxicological importance in the wood samples. The analysis was performed in the Brazilian Synchrotron Light Source Laboratory, using a white beam for excitation and a Si(Li) detector for X-ray detection. In several samples, P, K, Ca, Ti, Fe, Sr, Ba and Pb were quantified. The K/Ca, K/P and Pb/Ca ratios were found to decrease towards the bark.

  13. Cosmic X-ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1986-01-01

    The analysis of the beryllium-filtered data from Flight 17.020 was completed. The data base provided by the Wisconsin diffuse X-ray sky survey is being analyzed by correlating the B and C band emission with individual velocity components of neutral hydrogen. Work on a solid state detector to be used in high resolution spectroscopy of diffuse or extend X-ray sources is continuing. A series of 21 cm observations was completed. A paper on the effects of process parameter variation on the reflectivity of sputter-deposited tungsten-carvon multilayers was published.

  14. Polarization-modulated infrared spectroscopy and x-ray reflectivity of photosystem II core complex at the gas-water interface.

    PubMed Central

    Gallant, J; Desbat, B; Vaknin, D; Salesse, C

    1998-01-01

    The state of photosystem II core complex (PS II CC) in monolayer at the gas-water interface was investigated using in situ polarization-modulated infrared reflection absorption spectroscopy and x-ray reflectivity techniques. Two approaches for preparing and manipulating the monolayers were examined and compared. In the first, PS II CC was compressed immediately after spreading at an initial surface pressure of 5.7 mN/m, whereas in the second, the monolayer was incubated for 30 min at an initial surface pressure of 0.6 mN/m before compression. In the first approach, the protein complex maintained its native alpha-helical conformation upon compression, and the secondary structure of PS II CC was found to be stable for 2 h. The second approach resulted in films showing stable surface pressure below 30 mN/m and the presence of large amounts of beta-sheets, which indicated denaturation of PS II CC. Above 30 mN/m, those films suffered surface pressure instability, which had to be compensated by continuous compression. This instability was correlated with the formation of new alpha-helices in the film. Measurements at 4 degreesC strongly reduced denaturation of PS II CC. The x-ray reflectivity studies indicated that the spread film consists of a single protein layer at the gas-water interface. Altogether, this study provides direct structural and molecular information on membrane proteins when spread in monolayers at the gas-water interface. PMID:9826610

  15. Grazing-incidence small-angle X-ray scattering in a twofold rough-interface medium: a new theoretical approach using the q-eigenwave formalism.

    PubMed

    Chukhovskii, F N; Roshchin, B S

    2015-11-01

    Based on the rigorous Green function formalism to describe the grazing-incidence small-angle X-ray scattering (GISAXS) problem, a system of two linked integral equations is derived with respect to amplitudes of the reflected and transmitted plane q-eigenwaves (eigenstate functions) propagating through two homogeneous media separated from each other by a rough surface interface. To build up the coupled solutions of these basic equations beyond the perturbation theory constraint 2kσθ0 < 1, a simple iteration procedure is proposed as opposed to the self-consistent wave approach [Chukhovskii (2011). Acta Cryst. A67, 200-209; Chukhovski (2012). Acta Cryst. A68, 505-512]. Using the first-order iteration, analytical expressions for the averaged specular and non-specular scattering intensity distributions have been obtained. These expressions are further analysed in terms of the GISAXS parameters {k, θ, θ0} and surface finish ones {σ, l, h}, where θ and θ0 are the scattering and incidence angles of the X-rays, respectively, σ is the root-mean-square roughness, l is the correlation length, h is the fractal surface model index, k = 2π/λ, and λ is the X-ray wavelength. A direct way to determine the surface finish parameters from the experimental specular and diffuse scattering indicatrix scan data is discussed for an example of GISAXS measurements from rough surfaces of α-quartz and CdTe samples.

  16. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  17. Reflectivity (visible and near IR), Moessbauer, static magnetic, and X ray diffraction properties of aluminum-substituted hematites

    NASA Technical Reports Server (NTRS)

    Morris, Richard V.; Schulze, Darrell G.; Lauer, Howard V., Jr.; Agresti, David G.; Shelfer, Tad D.

    1992-01-01

    The effect of substituting iron by aluminum in polymorphs of Fe2O3 and FeOOH on their reflectivity characteristics was investigated by comparing data on visible and NIR reflectivities and on static magnetic, XRD, and Moessbauer properties for a family of aluminum-substituted hematites alpha-(Fe,Al)2O3, with compositions where the values of the Al/(Al+Fe) ratio were up to 0.61. Samples were prepared by oxidation of magnetite, dehydroxylation of goethite, and direct precipitation. The analytical methods used for obtaining diffuse reflectivity spectra (350-2200 nm), Moessbauer spectra, and static magnetic data are those described by Morris et al. (1989).

  18. Quadrupole lamp furnace for high temperature (up to 2050 K) synchrotron powder x-ray diffraction studies in air in reflection geometry

    SciTech Connect

    Sarin, P.; Yoon, W.; Jurkschat, K.; Zschack, P.; Kriven, W. M.

    2006-09-15

    A four-lamp thermal image furnace has been developed to conduct high temperature x-ray diffraction in reflection geometry on oxide ceramic powder samples in air at temperatures {<=}2050 K using synchrotron radiation. A refractory crucible made of Pt20%Rh alloy was used as a specimen holder. A material with well characterized lattice expansion properties was used as an internal crystallographic thermometer to determine the specimen temperature and displacement. The performance of the apparatus was verified by measurement of the thermal expansion properties of CeO{sub 2}, MgO, and Pt which were found to be within {+-}3% of the acceptable values. The advantages, limitations, and important considerations of the instrument developed are discussed.

  19. Fast method for multielemental analysis of plants and discrimination according to the anatomical part by total reflection X-ray fluorescence spectrometry.

    PubMed

    De la Calle, Inmaculada; Costas, Marta; Cabaleiro, Noelia; Lavilla, Isela; Bendicho, Carlos

    2013-05-01

    Fast and reliable analytical methodologies are required for quality control of plants in order to assure human health. Ultrasound-assisted extraction in combination with total reflection X-ray fluorescence is proposed as a fast and simple method for multielemental analysis of plants on a routine basis. For this purpose, five certified reference materials have been analysed for the determination of P, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn and Pb. Different extractant media (acids and oxidants) were tried. A mixture of diluted HNO(3)+HCl+HF, was selected as the best option for the achievement of complete extractions. Accurate and precise results can be reached in most cases along with a high sample throughput. Different plants (i.e., herbs, spices and medicinal plants) were analysed. Linear discriminant analysis together with the elemental concentrations allowed the differentiation of commercial preparations corresponding to flower, fruit and leaf.

  20. Portable ultrahigh-vacuum sample storage system for polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy

    SciTech Connect

    Watanabe, Yoshihide Nishimura, Yusaku F.; Suzuki, Ryo; Beniya, Atsushi; Isomura, Noritake; Uehara, Hiromitsu; Asakura, Kiyotaka; Takakusagi, Satoru; Nimura, Tomoyuki

    2016-03-15

    A portable ultrahigh-vacuum sample storage system was designed and built to investigate the detailed geometric structures of mass-selected metal clusters on oxide substrates by polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy (PTRF-XAFS). This ultrahigh-vacuum (UHV) sample storage system provides the handover of samples between two different sample manipulating systems. The sample storage system is adaptable for public transportation, facilitating experiments using air-sensitive samples in synchrotron radiation or other quantum beam facilities. The samples were transferred by the developed portable UHV transfer system via a public transportation at a distance over 400 km. The performance of the transfer system was demonstrated by a successful PTRF-XAFS study of Pt{sub 4} clusters deposited on a TiO{sub 2}(110) surface.

  1. Use of total reflection X-ray fluorescence (TXRF) for the evaluation of heavy metal poisoning due to the improper use of a traditional ayurvedic drug.

    PubMed

    Borgese, L; Zacco, A; Bontempi, E; Pellegatta, M; Vigna, L; Patrini, L; Riboldi, L; Rubino, F M; Depero, L E

    2010-09-05

    An Indian patient referred to Clinica del Lavoro 'L.Devoto' of Milano showed clinical signs of heavy metal poisoning, possibly related to a sustained 6-month use of approx. 3 g/day of a traditional preparation (a whitish powder with a 'mineral' appearance) to treat urological problems. To confirm the causal relationship between the disease and the use of such product, metal testing was performed on the patient's hair and the ayurvedic remedy samples by total reflection X-ray fluorescence (TXRF). For TXRF analysis 1-cm cut of the patient's hair was directly deposited onto the quartz glass sample carrier, then 10 microl of nitric acid 65% were added and dried in air. TXRF showed high versatility, rapid and simultaneous element detection, and short analysis time, thus supporting a wider use in emergency medicine and in forensic analyses. 2010 Elsevier B.V. All rights reserved.

  2. Analysis of human blood serum and human brain samples by total reflection X-ray fluorescence spectrometry applying Compton peak standardization

    NASA Astrophysics Data System (ADS)

    Marcó, L. M.; Greaves, E. D.; Alvarado, J.

    1999-10-01

    The method of using the Compton peak as internal standard in total reflection X-ray fluorescence (TXRF) determination is established for trace element determination of Fe, Cu, Zn, Se and Pt in human serum and of Cu and Zn in homogenized brain samples. A new method of spectrometer sensitivity calibration using spiked matrices with known amounts of trace elements is tested against established methods of matrix matching as well as internal element addition. The analytical results with the proposed procedure are compared to a certified international standard and to values with Atomic Absorption Spectrometry (AAS) obtaining analytical results of comparable accuracy and precision. The method is adequate for routine clinical analysis as it has the advantages of requiring very small amounts of material and simple preparations, which avoids the chemical digestion stage.

  3. Determination of Zn/Cu ratio and oligoelements in serum samples by total reflection X-ray fluorescence spectrometry for cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Marcó P., L. M.; Jiménez, E.; Hernández C., E. A.; Rojas, A.; Greaves, E. D.

    2001-11-01

    The method of quantification using the Compton peak as an internal standard, developed in a previous work, was applied to the routine determination of Fe, Cu, Zn and Se in serum samples from normal individuals and cancer patients by total reflection X-ray fluorescence spectrometry. Samples were classified according to age and sex of the donor, in order to determine reference values for normal individuals. Results indicate that the Zn/Cu ratio and the Cu concentration could prove to be useful tools for cancer diagnosis. Significant differences in these parameters between the normal and cancer group were found for all age ranges. The multielemental character of the technique, coupled with the small amounts of sample required and the short analysis time make it a valuable tool in clinical analysis.

  4. Reference materials for quality assurance in sea-water analysis: performance of total-reflection X-ray fluorescence in the intercomparison and certification stages

    NASA Astrophysics Data System (ADS)

    Freimann, Peter; Schmidt, Diether; Neubauer-Ziebarth, Astrid

    1993-02-01

    The certification of a sea-water reference material (CRM 403) was completed by the Community Bureau of Reference (BCR) of the Commission of the European Communities during an intercomparison exercise in which we were participants along with other highly experienced laboratories, who, beforehand, had given evidence of outstanding performance. Further, we participated in a feasibility study on estuarine water. In both studies we used total-reflection X-ray fluorescence analysis (TXRF) for the determination of V, Mn, Fe, Co, Ni, Cu, Zn, Pb and U on the nmol/kg level. The enrichment of the trace metals and the separation from the salt matrix were performed by complexation with sodium dibenzyldithiocarbamate and reverse-phase chromatography. In this paper, the high performance of our TXRF results is compared to other analytical techniques like voltammetric and atomic absorption methods.

  5. Wave-optical evaluation of interference fringes and wavefront phase in a hard-x-ray beam totally reflected by mirror optics

    SciTech Connect

    Yamauchi, Kazuto; Yamamura, Kazuya; Mimura, Hidekazu; Sano, Yasuhisa; Saito, Akira; Endo, Katsuyoshi; Souvorov, Alexei; Yabashi, Makina; Tamasaku, Kenji; Ishikawa, Tetsuya; Mori, Yuzo

    2005-11-10

    The intensity flatness and wavefront shape in a coherent hard-x-ray beam totally reflected by flat mirrors that have surface bumps modeled by Gaussian functions were investigated by use of a wave-optical simulation code. Simulated results revealed the necessity for peak-to-valley height accuracy of better than 1 nm at a lateral resolution near 0.1 mm to remove high-contrast interference fringes and appreciable wavefront phase errors. Three mirrors that had different surface qualities were tested at the 1 km-long beam line at the SPring-8/Japan Synchrotron Radiation Research Institute. Interference fringes faded when the surface figure was corrected below the subnanometer level to a spatial resolution close to 0.1 mm, as indicated by the simulated results.

  6. Thermal stability of hydrogenated diamond films in nitrogen ambience studied by reflection electron energy spectroscopy and X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Ren, Bing; Huang, Jian; Yu, Hongze; Yang, Weichuan; Wang, Lin; Pan, Zhangmin; Wang, Linjun

    2016-12-01

    (1 1 0)-oriented diamond films were grown by microwave plasma chemical vapor deposition technique, followed by an optimized hydrogen-plasma treatment process. Thermal stability of hydrogenated diamond films were studied by annealing in nitrogen atmosphere at temperature varied from 400 to 950 °C. Reflection electron energy spectroscopy associated with X-ray photoelectron spectroscopy indicates that approximate at. 50% hydrogen was present at the surface of hydrogenated diamond films, which is close to the theoretical value. Pinning effect in surface Fermi level in hydrogenated diamond films could not be eliminated by annealing in nitrogen until the temperature was exceeded 950 °C. The films underwent hydrogen desorption and subsequent graphitization mainly on the very surface region without significant bulk modification. Besides, hydrogenated diamond films annealed in N2 at 950 °C showed similar hydrophilicity and resistance to that of the oxidized one, indicating rupture of C-H bond on the surface of hydrogenated diamond films.

  7. Identification of an incommensurate FeAl{sub 2} overlayer on FeAl(110) using x-ray diffraction and reflectivity

    SciTech Connect

    Baddorf, A.P.; Chandavarkar, S.S.

    1995-06-30

    FeAl, like NiAl, crystallizes in the CsCl structure. Consequently the (110) planes contain equal amounts of Fe and Al distributed as interlocking rectangles. Unlike the NiAI(110) surface, which retains the (1{times}l) in-plane symmetry of the bulk, FeAl(l10) reconstructs to form an ordered, incommensurate overlayer. The reconstructed layer introduces x-ray diffraction rods at half-order positions along the [1{bar 1}0] direction, and displaced {plus_minus}0.2905 from integer positions along the [001] direction. Peak widths reveal excellent long range order. Specular reflectivity measurements above and below the Fe K{alpha} edge can be reproduced using a model containing a single reconstructed overlayer with an Fe:Al ratio of 1:2, consistent with FeA{sub I}2.

  8. Driving force behind adsorption-induced protein unfolding: a time-resolved X-ray reflectivity study on lysozyme adsorbed at an air/water interface.

    PubMed

    Yano, Yohko F; Uruga, Tomoya; Tanida, Hajime; Toyokawa, Hidenori; Terada, Yasuko; Takagaki, Masafumi; Yamada, Hironari

    2009-01-06

    Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence of the density profile at the air/water interface revealed that the molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose that the LSZ molecules initially adsorbed on the air/water interface have a flat unfolded structure, forming antiparallel beta-sheets as a result of hydrophobic interactions with the gas phase. In contrast, as adsorption continues, a second layer forms in which the molecules have a very loose structure having random coils as a result of hydrophilic interactions with the hydrophilic groups that protrude from the first layer.

  9. Quadrupole lamp furnace for high temperature (up to 2050 K) synchrotron powder x-ray diffraction studies in air in reflection geometry.

    SciTech Connect

    Sarin, P.; Yoon, W.; Jurkschat, K.; Zschack, P.; Kriven, W. M.; Univ. of Illinois; Frederick-Seitz Materials Research Lab.

    2006-09-01

    A four-lamp thermal image furnace has been developed to conduct high temperature x-ray diffraction in reflection geometry on oxide ceramic powder samples in air at temperatures {le} 2050 K using synchrotron radiation. A refractory crucible made of Pt20%Rh alloy was used as a specimen holder. A material with well characterized lattice expansion properties was used as an internal crystallographic thermometer to determine the specimen temperature and displacement. The performance of the apparatus was verified by measurement of the thermal expansion properties of CeO{sub 2}, MgO, and Pt which were found to be within {+-} 3% of the acceptable values. The advantages, limitations, and important considerations of the instrument developed are discussed.

  10. Relativistic Disk Reflection in the Neutron Star X-Ray BinaryXTE J1709-267 with NuSTAR

    NASA Astrophysics Data System (ADS)

    Ludlam, R. M.; Miller, J. M.; Cackett, E. M.; Degenaar, N.; Bostrom, A. C.

    2017-04-01

    We perform the first reflection study of the soft X-ray transient and Type 1 burst source XTE J1709-267 using NuSTAR observations during its 2016 June outburst. There was an increase in flux near the end of the observations, which corresponds to an increase from ∼0.04 L Edd to ∼0.06 L Edd assuming a distance of 8.5 kpc. We have separately examined spectra from the low- and high-flux intervals, which are soft and show evidence of a broad Fe K line. Fits to these intervals with relativistic disk reflection models have revealed an inner-disk radius of {13.8}-1.8+3.0 {R}g (where {R}g={GM}/{c}2) for the low-flux spectrum and {23.4}-5.4+15.6 {R}g for the high-flux spectrum at the 90% confidence level. The disk is likely truncated by a boundary layer surrounding the neutron star (NS) or the magnetosphere. Based on the measured luminosity and the accretion efficiency for a disk around an NS, we estimate that the theoretically expected size for the boundary layer would be ∼ 0.9{--}1.1 {R}g from the NS’s surface, which can be increased by spin or viscosity effects. Another plausible scenario is that the disk could be truncated by the magnetosphere. We place a conservative upper limit on the strength of the magnetic field at the poles (assuming {a}* =0 and {M}{NS}=1.4{M}ȯ ) of B≤slant 0.75-3.70× {10}9 G, though X-ray pulsations have not been detected from this source.

  11. Analysis of nutrition-relevant trace elements in human blood and serum by means of total reflection X-ray fluorescence (TXRF) spectroscopy

    NASA Astrophysics Data System (ADS)

    Stosnach, Hagen; Mages, Margarete

    2009-04-01

    In clinical service laboratories, one of the most common analytical tasks with regard to inorganic traces is the determination of the nutrition-relevant elements Fe, Cu, Zn, and Se. Because of the high numbers of samples and the commercial character of these analyses, a time-consuming sample preparation must be avoided. In this presentation, the results of total reflection X-ray fluorescence measurements with a low-power system and different sample preparation procedures are compared with those derived from analysis with common methods like Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The results of these investigations indicate that the optimal total reflection X-ray fluorescence analysis of the nutrition-relevant elements Fe, Cu, Zn, and Se can be performed by preparing whole blood and serum samples after dilution with ultrapure water and transferring 10 μl of internally standardized sample to an unsiliconized quartz glass sample carrier with subsequent drying in a laboratory oven. Suitable measurement time was found to be 600 s. The enhanced sample preparation by means of microwave or open digestion, in parts combined with cold plasma ashing, led to an improvement of detection limits by a factor of 2 for serum samples while for whole blood samples an improvement was only observed for samples prepared by means of microwave digestion. As the matrix elements P, S, Cl, and for whole blood Fe have a major influence on the detection limits, most probably a further enhancement of analytical quality requires the removal of the organic matrix. However, for the routine analysis of the nutrition-relevant elements, the dilution preparation was found to be sufficient.

  12. X-ray spectroscopy of magnetic CVs

    NASA Astrophysics Data System (ADS)

    Matt, Giorgio

    I discuss two topics in X-ray spectroscopy of magnetic CVs: reflection from the white dwarf surface, and opacity effects in the post shock plasma. I also briefly mention future observational perspectives, with particular emphasis on the Constellation X-ray mission.

  13. Resonant soft x-ray reflectivity of Me/B4C multilayers near the boron K edge

    SciTech Connect

    Ksenzov, Dmitriy; Schlemper, Christoph; Pietsch, Ullrich

    2010-09-01

    Energy dependence of the optical constants of boron carbide in the short period Ru/B4C and Mo/B4C multilayers (MLs) are evaluated from complete reflectivity scans across the boron K edge using the energy-resolved photon-in-photon-out method. Differences between the refractive indices of the B4Cmaterial inside and close to the surface are obtained from the peak profile of the first order ML Bragg peak and the reflection profile near the critical angle of total external reflection close to the surface. Where a Mo/B4C ML with narrow barrier layers appears as a homogeneous ML at all energies, a Ru/B4C ML exhibits another chemical nature of boron at the surface compared to the bulk. From evaluation of the critical angle of total external reflection in the energy range between 184 and 186 eV, we found an enriched concentration of metallic boron inside the Ru-rich layer at the surface, which is not visible in other energy ranges.

  14. On amplitude beam splitting of tender X-rays (2-8 keV photon energy) using conical diffraction from reflection gratings with laminar profile.

    PubMed

    Jark, Werner; Eichert, Diane

    2016-01-01

    Conical diffraction is obtained when a radiation beam impinges onto a periodically ruled surface structure parallel or almost parallel to the ruling. In this condition the incident intensity is diffracted through an arc, away from the plane of incidence. The diffracted intensity thus lies on a cone, which leads to the name `conical diffraction'. In this configuration almost no part of the ruled structure will produce any shadowing effect for the incident or the diffracted beam. Then, compared with a grating in the classical orientation, relatively higher diffraction efficiencies will be observed for fewer diffraction orders. When the incident beam is perfectly parallel to the grooves of a rectangular grating profile, the symmetry of the setup causes diffraction of the intensity symmetrically around the plane of incidence. This situation was previously tested experimentally in the VUV spectral range for the amplitude beam splitting of a radiation beam with a photon energy of 25 eV. In this case the ideally expected beam splitting efficiency of about 80% for the diffraction into the two first orders was confirmed for the optimum combination of groove depth and angle of grazing incidence. The feasibility of the amplitude beam splitting for hard X-rays with 12 keV photon energy by use of the same concept was theoretically confirmed. However, no related experimental data are presented yet, not even for lower energy soft X-rays. The present study reports the first experimental data for the conical diffraction from a rectangular grating profile in the tender X-ray range for photon energies of 4 keV and 6 keV. The expected symmetries are observed. The maximum absolute efficiency for beam splitting was measured to be only about 30%. As the reflectivity of the grating coating at the corresponding angle of grazing incidence was found to be only of the order of 50%, the relative beam splitting efficiency was thus 60%. This is to be compared also here with an ideally

  15. Chest X-Ray

    MedlinePlus Videos and Cool Tools

    ... Site Index A-Z Spotlight Recently posted: Anal Cancer Facet Joint Block Video: Lung Cancer Screening Video: Upper GI Tract X-ray Video: ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  16. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  17. X-Ray

    MedlinePlus

    ... of gray. For some types of X-ray tests, a contrast medium — such as iodine or barium — is introduced into your body to provide greater detail on the images. X-ray technology is used to examine many parts of the ...

  18. Abdominal x-ray

    MedlinePlus

    An abdominal x-ray is an imaging test to look at organs and structures in the abdomen. Organs include the spleen, stomach, and intestines. When the test is done to look at the bladder and kidney structures, it is called a KUB (kidneys, ureters, bladder) x-ray.

  19. X-ray lasers

    SciTech Connect

    Elton, R.C.

    1990-01-01

    This paper provides a source that surveys the fundamentals of x-ray lasers and summarizes recent advances. The author emphasizes x-ray lasers created using high temperature plasmas as the medium. Specific topics discussed included electron-collisional excitation pumping, plasma laser pumping, and gamma-ray lasers. Numerous literature references provided.

  20. X-ray lasers

    SciTech Connect

    Elton, R.C.

    1990-01-01

    This book is both an introduction to x-ray lasers and a how-to-guide for specialists. It provides comprehensive overview and describes useful examples of analysis and experiments as background and guidance for researchers undertaking new laser designs. The book collects the knowledge and experience gained in two decades of x-ray laser development.

  1. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  2. X-ray Polarimetry

    NASA Astrophysics Data System (ADS)

    Kallman, T.

    In spite of the recent advances in X-ray instrumentation, polarimetry remains an area which has been virtually unexplored in the last 20 years. The scientific motivation to study polarization has increased during this time: emission models designed to repro- duce X-ray spectra can be tested using polarization, and polarization detected in other wavelength bands makes clear predictions as to the X-ray polarization. Polarization remains the only way to infer geometrical properties of sources which are too small to be spatially resolved. At the same time, there has been recent progress in instrumen- tation which is likely to allow searches for X-ray polarization at levels significantly below what was possible for early detectors. In this talk I will review the history of X-ray polarimetry, discuss some experimental techniques and the scientific problems which can be addressed by future experiments.

  3. X-ray generator

    DOEpatents

    Dawson, John M.

    1976-01-01

    Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

  4. History of Chandra X-Ray Observatory

    NASA Image and Video Library

    2000-04-01

    This Chandra X-Ray Observatory (CXO) image is a spectrum of a black hole, which is similar to the colorful spectrum of sunlight produced by a prism. The x-rays of interest are shown here recorded in bright stripes that run rightward and leftward from the center of the image. These x-rays are sorted precisely according to their energy with the highest-energy x-rays near the center of the image and the lower-energy x-rays farther out. The spectrum was obtained by using the Low Energy Transmission Grating (LETG), which intercepts x-rays and changes their direction by the amounts that depend sensitively on the x-ray energy. The assembly holds 540 gold transmission gratings. When in place behind the mirrors, the gratings intercept the x-rays reflected from the telescope. The bright spot at the center is due to a fraction of the x-ray radiation that is not deflected by the LETG. The spokes that intersect the central spot and the faint diagonal rays that flank the spectrum itself are artifacts due to the structure that supports the LETG grating elements. (Photo credit: NASA Cfa/J. McClintock et al)

  5. Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

    NASA Technical Reports Server (NTRS)

    Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

    2010-01-01

    An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

  6. Characterization of surface functionality of coals by photoacoustic FTIR (PAIFT) spectroscopy, reflectance infrared microspectrometry, and X-ray photoelectron spectroscopy

    SciTech Connect

    Lynch, B.M.; Lancaster, L.; Mac Phee, J.A.

    1987-04-01

    This paper illustrates detection by the technique of PhotoAcoustic Infrared Fourier Transform (PAIFT) spectroscopy of new carbonyl-type functionality at the surfaces of powdered bituminous coals, generated by both base-promoted and by thermal decomposition of precursor peroxide species, postulated as ubiquitous constituents at the surfaces of all except the most freshly prepared samples. In artificially oxidized coals, there are quantitative associations between the level of carbonyl content revealed by PAIFT spectra and plastic properties of the coals. Maceral components and mineral inclusions have been identified and characterized in sectioned, polished surfaces of Canadian bituminous coals using reflection FTIR microspectrometry; this direct examination shows promise for real-time monitoring of various reactions at surfaces.

  7. Comparative study of the X-ray reflectivity and in-depth profile of a-C, B₄C and Ni coatings at 0.1-2 keV.

    PubMed

    Kozhevnikov, I V; Filatova, E O; Sokolov, A A; Konashuk, A S; Siewert, F; Störmer, M; Gaudin, J; Keitel, B; Samoylova, L; Sinn, H

    2015-03-01

    The use of soft X-rays near the carbon edge of absorption (270-300 eV) greatly enhances studies in various branches of science. However, the choice of reflecting coatings for mirrors operating in free-electron and X-ray free-electron laser (FEL and XFEL) beamlines in this spectral range is not so evident and experimental justifications of the mirror efficiency are rather limited. In the present paper it is demonstrated experimentally that the reflectivity of B4C- and Ni-coated grazing-incidence mirrors is high enough for their operation in FEL or XFEL beamlines near the carbon K-edge of absorption. The minimal reflectivity of both mirrors proves to exceed 80% near the carbon absorption edge at a grazing angle of 0.6°. An in-depth profile of the chemical elements composing the reflecting coatings is reconstructed based on analysis of a set of reflectivity curves measured versus the grazing angle at different photon energies in the soft X-ray spectral region. This allows us to predict correctly the mirror reflectivity at any X-ray energy and any grazing angle.

  8. Stellar X-Ray Polarimetry

    NASA Technical Reports Server (NTRS)

    Swank, J.

    2011-01-01

    Most of the stellar end-state black holes, pulsars, and white dwarfs that are X-ray sources should have polarized X-ray fluxes. The degree will depend on the relative contributions of the unresolved structures. Fluxes from accretion disks and accretion disk corona may be polarized by scattering. Beams and jets may have contributions of polarized emission in strong magnetic fields. The Gravity and Extreme Magnetism Small Explorer (GEMS) will study the effects on polarization of strong gravity of black holes and strong magnetism of neutron stars. Some part of the flux from compact stars accreting from companion stars has been reflected from the companion, its wind, or accretion streams. Polarization of this component is a potential tool for studying the structure of the gas in these binary systems. Polarization due to scattering can also be present in X-ray emission from white dwarf binaries and binary normal stars such as RS CVn stars and colliding wind sources like Eta Car. Normal late type stars may have polarized flux from coronal flares. But X-ray polarization sensitivity is not at the level needed for single early type stars.

  9. X-ray crystallography

    NASA Technical Reports Server (NTRS)

    2001-01-01

    X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

  10. X-ray crystallography

    NASA Technical Reports Server (NTRS)

    2001-01-01

    X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

  11. Observation of femtosecond X-ray interactions with matter using an X-ray-X-ray pump-probe scheme.

    PubMed

    Inoue, Ichiro; Inubushi, Yuichi; Sato, Takahiro; Tono, Kensuke; Katayama, Tetsuo; Kameshima, Takashi; Ogawa, Kanade; Togashi, Tadashi; Owada, Shigeki; Amemiya, Yoshiyuki; Tanaka, Takashi; Hara, Toru; Yabashi, Makina

    2016-02-09

    Resolution in the X-ray structure determination of noncrystalline samples has been limited to several tens of nanometers, because deep X-ray irradiation required for enhanced resolution causes radiation damage to samples. However, theoretical studies predict that the femtosecond (fs) durations of X-ray free-electron laser (XFEL) pulses make it possible to record scattering signals before the initiation of X-ray damage processes; thus, an ultraintense X-ray beam can be used beyond the conventional limit of radiation dose. Here, we verify this scenario by directly observing femtosecond X-ray damage processes in diamond irradiated with extraordinarily intense (∼10(19) W/cm(2)) XFEL pulses. An X-ray pump-probe diffraction scheme was developed in this study; tightly focused double-5-fs XFEL pulses with time separations ranging from sub-fs to 80 fs were used to excite (i.e., pump) the diamond and characterize (i.e., probe) the temporal changes of the crystalline structures through Bragg reflection. It was found that the pump and probe diffraction intensities remain almost constant for shorter time separations of the double pulse, whereas the probe diffraction intensities decreased after 20 fs following pump pulse irradiation due to the X-ray-induced atomic displacement. This result indicates that sub-10-fs XFEL pulses enable conductions of damageless structural determinations and supports the validity of the theoretical predictions of ultraintense X-ray-matter interactions. The X-ray pump-probe scheme demonstrated here would be effective for understanding ultraintense X-ray-matter interactions, which will greatly stimulate advanced XFEL applications, such as atomic structure determination of a single molecule and generation of exotic matters with high energy densities.

  12. pH-dependent conformational changes of diphtheria toxin adsorbed to lipid monolayers by neutron and X-ray reflection

    NASA Astrophysics Data System (ADS)

    Kent, Michael; Yim, Hyun; Satija, Sushil; Kuzmenko, Ivan

    2006-03-01

    Several important bacterial toxins, such as diphtheria, tetanus, and botulinum, invade cells through a process of high affinity binding, internalization via endosome formation, and subsequent membrane penetration of the catalytic domain activated by a pH drop in the endosome. These toxins are composed of three domains: a binding domain, a translocation domain, and an enzyme. The translocation process is not well understood with regard to the detailed conformational changes that occur at each step, To address this, we performed neutron reflectivity measurements for diphtheria toxin bound to lipid monolayers as a function of pH. While the final membrane inserted conformation will not be reproduced with the present monolayer system, important insights can still be gained into several intermediate stages. In particular, we show that no adsorption occurs at pH = 7.6, but strong adsorption occurs over at a pH range from 6.5 to 6.0. Following binding, at least two stages of conformational change occur, as the thickness increases from pH 6.3 to 5.3 and then decreases from pH 5.3 to 4.5. In addition, the dimension of the adsorbed layer substantially exceeds that of the largest dimension in the crystal structure of monomeric diphtheria, suggesting that the toxin may be present as multimers.

  13. Biomonitoring of environmental pollution using growth tree rings of Tipuana tipu: Quantification by synchrotron radiation total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Geraldo, S. M.; Canteras, F. B.; Moreira, S.

    2014-02-01

    Currently, many studies use the bioindicators to qualitatively and/or quantitatively measure pollution. The analyses of tree growth rings represent one such bioindicator as changes in the environment are often recorded as impressions in the wood. The main objective of the present study is to examine the growth rings of Tipuana tipu - a member of the Leguminosae family that is native to Argentina and Bolivia and was introduced in Brazil as an ornamental plant - for potentially toxic elements. T. tipu is one of the most common trees in the urban landscape of Sao Paulo city and would provide an accurate reflection of environment changes. Tree ring samples previously dated using Synchrotron Radiation Total Reflection X-ray Fluorescence were collected from strategic locations in Sao Paulo. These locations include Piracicaba (SP) that has little access and small flow traffic and the campus of the University of São Paulo. Some trace elements present concentrations higher than considered as normal in some periods. In São Paulo city, samples collected from the campus of University of São Paulo (Butantã), showed the highest toxicity, with concentrations above the tolerable limit for the elements: Cr, Cu, and Pb. For the samples collected in Piracicaba city, one sample presented highest concentrations for the majority of the elements when compared to the other four samples collected at the same place, exceeding the toxicity limits for: Cr, Ni, Cu, and Pb.

  14. Neutron and X-Ray Reflectivity Studies of the Adsorption of Aerosol-OT at the Air-Water Interface: The Structure of the Calcium Salt

    PubMed

    Li; Lee; Thomas; Penfold

    1997-03-15

    We have used neutron and X-ray reflection to determine the structure of a layer of calcium bis-(2-ethyl 1-hexyl) sulphosuccinate (Aerosol-OT or AOT) adsorbed at the air/solution interface. The widths of the distributions of the chains and head groups of the molecule, and their positions in relation to the underlying water, have been measured at four concentrations varying from the solubility limit (CMC) at 4 x 10(-4) M to 1 x 10(-6) M. Over this concentration range the coverage changes from 68 ± 3 to 142 ± 8 Å2 per AOT unit. The structure of the layer both is quite different from that of NaAOT and varies quite differently with surface concentration. The Ca(AOT)2 layer is slightly (1 Å) further out from the water, but the chain region is thinner for the calcium surfactant. This is reflected most in the greatly reduced chain to head separation, which drops from about 6 Å in NaAOT to about 4 Å in Ca(AOT)2.

  15. Composition determination of quaternary GaAsPN layers from single X-ray diffraction measurement of quasi-forbidden (002) reflection

    SciTech Connect

    Tilli, J.-M. Jussila, H.; Huhtio, T.; Sopanen, M.; Yu, K. M.

    2014-05-28

    GaAsPN layers with a thickness of 30 nm were grown on GaP substrates with metalorganic vapor phase epitaxy to study the feasibility of a single X-ray diffraction (XRD) measurement for full composition determination of quaternary layer material. The method is based on the peak intensity of a quasi-forbidden (002) reflection, which is shown to vary with changing arsenic content for GaAsPN. The method works for thin films with a wide range of arsenic contents and shows a clear variation in the reflection intensity as a function of changing layer composition. The obtained thicknesses and compositions of the grown layers are compared with accurate reference values obtained by Rutherford backscattering spectroscopy combined with nuclear reaction analysis measurements. Based on the comparison, the error in the XRD defined material composition becomes larger with increasing nitrogen content and layer thickness. This suggests that the dominating error source is the deteriorated crystal quality due to the nonsubstitutional incorporation of nitrogen into the crystal lattice and strain relaxation. The results reveal that the method overestimates the arsenic and nitrogen content within error margins of about 0.12 and about 0.025, respectively.

  16. Provenance of Holocene sediment on the Chukchi-Alaskan margin based on combined diffuse spectral reflectance and quantitative X-Ray Diffraction analysis

    USGS Publications Warehouse

    Ortiz, J.D.; Polyak, L.; Grebmeier, J.M.; Darby, D.; Eberl, D.D.; Naidu, S.; Nof, D.

    2009-01-01

    Sediment clay and silt mineral assemblages provide an excellent means of assessing the provenance of fine-grained Arctic sediment especially when a unique mineral assemblage can be tied to specific source areas. The diffuse spectral reflectance (DSR) first derivative measurements and quantitative X-Ray Diffraction (qXRD) on a high-resolution sediment core from the continental slope north of Alaska constrain the sediment mineralogy. DSR results are augmented by measurements on several adjacent cores and compared to surface sediment samples from the northern Alaskan shelf and slope. Using Principal Component Analysis (PCA), we infer that the three leading DSR modes relate to mixtures of smectite + dolomite, illite + goethite, and chlorite + muscovite. This interpretation is consistent with the down core qXRD results. While the smectite + dolomite, and illite + goethite factors show increased variability down core, the chlorite + muscovite factor had highest positive loadings in the middle Holocene, between ca. 6.0 and 3.6??ka. Because the most likely source of the chlorite + muscovite suite in this vicinity lies in the North Pacific, we argue that the oscillations in chlorite + muscovite values likely reflect an increase in the inflow of Pacific water to the Arctic through the Bering Strait. The time interval of this event is associated in other parts of the globe with a non-linear response of the climate system to the decrease in insolation, which may be related to changes in water exchange between the Pacific and Arctic Ocean. ?? 2009 Elsevier B.V.

  17. X-ray laser

    DOEpatents

    Nilsen, Joseph

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  18. X-ray superbubbles

    NASA Technical Reports Server (NTRS)

    Cash, W.

    1983-01-01

    Four regions of the galaxy, the Cygnus Superbubble, the Eta Carina complex, the Orion/Eridanus complex, and the Gum Nebula, are discussed as examples of collective effects in the interstellar medium. All four regions share certain features, indicating a common structure. The selection effects which determine the observable X-ray properties of the superbubbles are discussed, and it is demonstrated that only a very few more in our Galaxy can be detected in X rays. X-ray observation of extragalactic superbubbles is shown to be possible but requires the capabilities of a large, high quality, AXAF class observatory.

  19. Abdomen X-Ray (Radiography)

    MedlinePlus

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

  20. Total reflection X-ray fluorescence spectrometric determination of elements in water hyacinth from the Lerma River

    NASA Astrophysics Data System (ADS)

    Tejeda, S.; Zarazúa, G.; Ávila-Pérez, P.; Carapia-Morales, L.; Martínez, T.

    2010-06-01

    The Lerma River is one of the most polluted body water in Mexico. For this reason, only the highly resistant organisms such as water hyacinth are able to reproduce in this river. The aim of this work was to evaluate the concentration of K, S, Fe, Ca, Mn, Ti, Zn, Sr, Rb, Cu, Cr, Ni, Pb and Br in roots of water hyacinth ( Eichhornia crassipes) from the Lerma River. The samples were collected from five sites in the river and analyzed in triplicate using a TXRF Spectrometer 'TX-2000 Ital Structures' with a Si(Li) detector and a resolution of 140 eV (FWHM) at Mn Kα. A Mo tube (40 kV, 30 mA) with 17.4 KeV excitation energy was used for a counting time of 500 s. Results show that the average metal concentration in the water hyacinth roots decrease in the following order: K (9698.2 µg/g) > S (7593.3 µg/g) > Fe (4406.6 µg/g) > Ca (2601.8 µg/g) > Mn (604.2 µg/g) > Ti (230.7 µg/g) > Zn (51.65 µg/g) > Sr (43.55 µg/g) > Rb (18.61 µg/g) > Cu (12.78 µg/g) > Cr (6.45 µg/g) > Ni (4.68 µg/g) > Pb (4.32 µg/g) > Br (4.31 µg/g) and the bioconcentration factors in the water hyacinth decrease in the sequence: Ti > Fe > Mn > Cu > Ni > Zn > S > Pb > Rb > K > Cr > Sr > Br > Ca. The concentrations in roots of water hyacinth reflect the high pollution level of the river.

  1. X-rays from Saturn Pose Puzzles

    NASA Astrophysics Data System (ADS)

    2004-03-01

    The first clear detection of X-rays from the giant, gaseous planet Saturn has been made with NASA's Chandra X-ray Observatory. Chandra's image shows that the X-rays are concentrated near Saturn's equator, a surprising result since Jupiter's X-ray emission is mainly concentrated near the poles. Existing theories cannot easily explain the intensity or distribution of Saturn's X-rays. Chandra observed Saturn for about 20 hours in April of 2003. The spectrum, or distribution with energy of the X-rays, was found to be very similar to that of X-rays from the Sun. "This indicates that Saturn's X-ray emission is due to the scattering of solar X-rays by Saturn's atmosphere," said Jan-Uwe Ness, of the University of Hamburg in Germany and lead author of a paper discussing the Saturn results in an upcoming issue of Astronomy & Astrophysics. "It's a puzzle, since the intensity of Saturn's X-rays requires that Saturn reflects X-rays fifty times more efficiently than the Moon." The observed 90 megawatts of X-ray power from Saturn's equatorial region is roughly consistent with previous observations of the X-radiation from Jupiter's equatorial region. This suggests that both giant, gaseous planets reflect solar X-rays at unexpectedly high rates. Further observations of Jupiter will be needed to test this possibility. The weak X-radiation from Saturn's south-polar region presents another puzzle (the north pole was blocked by Saturn's rings during this observation). Saturn's magnetic field, like that of Jupiter, is strongest near the poles. X-radiation from Jupiter is brightest at the poles because of auroral activity due to the enhanced interaction of high-energy particles from the Sun with its magnetic field. Since spectacular ultraviolet polar auroras have been observed to occur on Saturn, Ness and colleagues expected that Saturn's south pole might be bright in X-rays. It is not clear whether the auroral mechanism does not produce X-rays on Saturn, or for some reason concentrates

  2. X-ray scattering techniques for coherent imaging in reflection geometry, measurement of mutual intensity, and symmetry determination in disordered materials

    NASA Astrophysics Data System (ADS)

    Parks, Daniel H.

    The advent of highly-coherent x-ray light sources, such as those now available world-wide in modern third-generation synchrotrons and increasingly available in free-electron lasers, is driving the need for improved analytical and experimental techniques which exploit the coherency of the generated light. As the light illuminating a sample approaches full coherence, a simple Fourier transform describes the diffraction pattern generated by the scattered light in the far field; because the Fourier transform of an object is unique, coherent scattering can directly probe local structure in the scattering object instead of bulk properties. In this dissertation, we exploit the coherence of Advanced Light Source beamline 12.0.2 to build three types of novel coherent scattering microscopes. First, we extend the techniques of coherent diffractive imaging and Fourier transform holography, which uses iterative computational methods to invert oversampled coherent speckle patterns, into reflection geometry. This proof-of-principle experiment demonstrates a method by which reflection Bragg peaks, such as those from the orbitally-ordered phase of complex metal oxides, might eventually be imaged. Second, we apply a similar imaging method to the x-ray beam itself to directly image the mutual coherence function with only a single diffraction pattern. This technique supersedes the double-slit experiments commonly seen in the scattering literature to measure the mutual intensity function by using a set of apertures which effectively contains all possible double slit geometries. Third, we show how to evaluate the speckle patterns taken from a labyrinthine domain pattern for "hidden" rotational symmetries. For this measurement, we modify the iterative algorithms used to invert speckle patterns to generate a large number of domain configurations with the same incoherent scattering profile as the candidate pattern and then use these simulations as the basis for a statistical inference of

  3. X-ray calorimeters

    NASA Astrophysics Data System (ADS)

    Porter, F. Scott

    X-ray calorimeter instruments for astrophysics have seen rapid development since they were invented in 1984. The prime instrument on all currently planned X-ray spectroscopic observatories is based on calorimeter technology. This relatively simple detection concept that senses the energy of an incident photon by measuring the temperature rise of an absorber material at very low temperatures can form the basis of a very high-performance, non-dispersive spectrometer. State-of-theart calorimeter instruments have resolving powers of over 3000, large simultaneous bandpasses, and near unit efficiency. This coupled with the intrinsic imaging capability of a pixilated X-ray calorimeter array, allows true spectral-spatial instruments to be constructed. This chapter briefly reviews the detection scheme, the state of the art in X-ray calorimeter instruments and the future outlook for this technology.

  4. X-ray - skeleton

    MedlinePlus

    ... medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this page, ... ray views may be uncomfortable. If the whole skeleton is being imaged, the test usually takes 1 ...

  5. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  6. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1992-01-01

    This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

  7. Optical systems for synchrotron radiation: lecture 4. Soft x-ray imaging systems

    SciTech Connect

    Howells, M.R.

    1986-04-01

    The history and present techniques of soft x-ray imaging are reviewed briefly. The physics of x-ray imaging is described, including the temporal and spatial coherence of x-ray sources. Particular technologies described are: contact x-ray microscopy, zone plate imaging, scanned image zone plate microscopy, scanned image reflection microscopy, and soft x-ray holography and diffraction. (LEW)

  8. X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van Paradijs, Jan; van den Heuvel, Edward Peter Jacobus

    1997-01-01

    Preface; 1. The properties of X-ray binaries, N. E. White, F. Nagase and A. N. Parmar; 2. Optical and ultraviolet observations of X-ray binaries J. van Paradijs and J. E. McClintock; 3. Black-hole binaries Y. Tanaka and W. H. G. Lewin; 4. X-ray bursts Walter H. G. Lewin, Jan Van Paradijs and Ronald E. Taam; 5. Millisecond pulsars D. Bhattacharya; 6. Rapid aperiodic variability in binaries M. van der Klis; 7. Radio properties of X-ray binaries R. M. Hjellming and X. Han; 8. Cataclysmic variable stars France Anne-Dominic Córdova; 9. Normal galaxies and their X-ray binary populations G. Fabbiano; 10. Accretion in close binaries Andrew King; 11. Formation and evolution of neutron stars and black holes in binaries F. Verbunt and E. P. J. van den Heuvel; 12. The magnetic fields of neutron stars and their evolution D. Bhattacharya and G. Srinivasan; 13. Cosmic gamma-ray bursts K. Hurley; 14. A catalogue of X-ray binaries Jan van Paradijs; 15. A compilation of cataclysmic binaries with known or suspected orbital periods Hans Ritter and Ulrich Kolb; References; Index.

  9. Structural analysis of PTCDA monolayers on epitaxial graphene with ultra-high vacuum scanning tunneling microscopy and high-resolution X-ray reflectivity

    NASA Astrophysics Data System (ADS)

    Emery, Jonathan D.; Wang, Qing Hua; Zarrouati, Marie; Fenter, Paul; Hersam, Mark C.; Bedzyk, Michael J.

    2011-09-01

    Epitaxial graphene, grown by thermal decomposition of the SiC (0001) surface, is a promising material for future applications due to its unique and superlative electronic properties. However, the innate chemical passivity of graphene presents challenges for integration with other materials for device applications. Here, we present structural characterization of epitaxial graphene functionalized by the organic semiconductor perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA). A combination of ultra-high vacuum scanning tunneling microscopy (STM) and high-resolution X-ray reflectivity (XRR) is used to extract lateral and vertical structures of 0, 1, and 2 monolayer (ML) PTCDA on epitaxial graphene. Both Fienup-based phase-retrieval algorithms and model-based least-squares analyses of the XRR data are used to extract an electron density profile that is interpreted in terms of a stacking sequence of molecular layers with specific interlayer spacings. Features in the STM and XRR analysis indicate long-range molecular ordering and weak π-π* interactions binding PTCDA molecules to the graphene surface. The high degree of both lateral and vertical ordering of the self-assembled film demonstrates PTCDA functionalization as a viable route for templating graphene for the growth and deposition of additional materials required for next-generation electronics and sensors.

  10. Reflectivity measurements in the vacuum ultraviolet wavelength range on technical surfaces for the Wolter I telescope on board the X-ray astronomy satellite ROSAT

    NASA Astrophysics Data System (ADS)

    Stephan, K. H.; Braeuninger, H.; Kaase, H.; Metzdorf, J.

    1986-08-01

    The results of reflectivity measurements in the vacuum ultraviolet wavelength region (VUV) on technical surfaces are described which are used in the Wolter I-telescope on board the German X-ray astronomy satellite ROSAT. The materials investigated are the special iron-nickel alloy Invar and a carbon fibre compound (CFK). The centre connecting flange for the parabolic and hyperbolic mirror sections of the telescope is made of Invar. CFK is used for the thermal baffle in front of the telescope. It had to be checked whether the structure of the centre flange and the thermal baffle sufficiently suppress scattered ultraviolet radiation in order to avoid a substantial background level in the detectors which are located in the focal plane of the telescope. The detectors consist of two positional sensitive proportional counters (PSPC) with a spatial resolution of 0.5 arc mm and an image converter with a resolution of a few arc sec. The detectors are mounted on a carrousel platform and are intended to be positioned alternatively in the focal plane

  11. Near-surface density of ion-implanted Si studied by Rutherford backscattering and total-reflection x-ray fluorescence

    SciTech Connect

    Klockenkaemper, R.; Becker, M.; Bohlen, A. von; Becker, H.W.; Krzyzanowska, H.; Palmetshofer, L.

    2005-08-01

    The implantation of ions in solids is of high technical relevance. The different effects within the solid target caused by the ion bombardment can be investigated by depth profiling of near-surface layers. As and Co ions were implanted in Si wafers: As ions with a fluence of 1x10{sup 17}/cm{sup 2} and an energy of 100 keV and Co ions with 1x10{sup 16}/cm{sup 2} at 25 keV. Subsequently depth profiling was carried out by Rutherford backscattering spectrometry as well as by total-reflection x-ray fluorescence analysis which was combined with differential weighing and interferometry after repeated large-surface sputter etching. Over and above the amorphization of the Si crystal, two other essential effects were observed: (i) a swelling or expansion of the original Si crystal in the near-surface region, in particular in the case of the As implantation, and (ii) a shrinking or compression of the Si crystal for deeper sublayers especially distinct for the Co implantation. On the other hand, a high surface enrichment of implanted ions was found for the As implantation while only a low surface concentration was detected for the Co implantation.

  12. X-ray Reflectivity Study of the Interaction of an Imidazolium-Based Ionic Liquid with a Soft Supported Lipid Membrane.

    PubMed

    Bhattacharya, G; Giri, R P; Saxena, H; Agrawal, V V; Gupta, A; Mukhopadhyay, M K; Ghosh, S K

    2017-02-07

    Ionic liquids (ILs) are important for their antimicrobial activity and are found to be toxic to some microorganisms. To shed light on the mechanism of their activities, the interaction of an imidazolium-based IL 1-butyl-3-methylimidazolium tetrfluoroborate ([BMIM][BF4]) with E. coli bacteria and cell-membrane-mimicking lipid mono- and bilayers has been studied. The survival of the bacteria and corresponding growth inhibition are observed to be functions of the concentration of the IL. The IL alters the pressure-area isotherm of the monolayer formed at an air-water interface by the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid. The in-plane elasticity of the lipid layer is reduced as a consequence of the insertion of this IL. The X-ray reflectivity study from a polymer-supported lipid bilayer shows strong perturbation in the self-assembled structure of the bilayer due to the interaction. As a consequence, there is a considerable decrease in bilayer thickness and a corresponding increase in electron density. These results, however, depend on the chain configurations of the lipid molecules.

  13. Determination of calcium, potassium, manganese, iron, copper and zinc levels in representative samples of two onion cultivars using total reflection X-ray fluorescence and ultrasound extraction procedure

    NASA Astrophysics Data System (ADS)

    Alvarez, J.; Marcó, L. M.; Arroyo, J.; Greaves, E. D.; Rivas, R.

    2003-12-01

    The chemical characterization of onion cultivar samples is an important tool for the enhancement of their productivity due to the fact that chemical composition is closed related to the quality of the products. A new sample preparation procedure for elemental characterization is proposed, involving the acid extraction of the analytes from crude samples by means of an ultrasonic bath, avoiding the required digestion of samples in vegetable tissue analysis. The technique of total reflection X-ray fluorescence (TXRF) was successfully applied for the simultaneous determination of the elements Ca, K, Mn, Fe, Cu and Zn. The procedure was compared with the wet ashing and dry ashing procedures for all the elements using multivariate analysis and the Scheffé test. The technique of flame atomic absorption spectrometry (FAAS) was employed for comparison purposes and accuracy evaluation of the proposed analysis method. A good agreement between the two techniques was found when using the dry ashing and ultrasound leaching procedures. The levels of each element found for representative samples of two onion cultivars (Yellow Granex PRR 502 and 438 Granex) were also compared by the same method. Levels of K, Mn and Zn were significantly higher in the 438 Granex cultivar, while levels of Ca, Fe and Cu were significantly higher in the Yellow Granex PRR 502 cultivar.

  14. Comparative study of trace element contents in human full-term placenta and fetal membranes by total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Kubala-Kukuś, A.; Banaś, D.; Braziewicz, J.; Majewska, U.; Pajek, M.

    2003-04-01

    The total reflection X-ray fluorescence (TXRF) method was applied to study the influence of environmental pollution on the contents of trace elements in human full-term placenta and fetal membranes. The samples were collected from the donors living in two regions characterised by different levels of environmental pollution. In this comparative study, based on relatively large (˜100) populations, the concentrations of approximately 20 trace elements (P-Pb) were determined in the samples. In particular, the paper discusses the role of 'truncation' of measured concentration distribution by the detection limit of the TXRF method in context of comparative studies. First, the importance of the developed method of reconstruction of original concentration distribution, to derive the correct concentrations of trace elements, is described and demonstrated and, second, the statistical tests, which can be used to compare the truncated, or reconstructed, concentration distributions are discussed. Finally, the statistically significant differences of trace element concentrations found in both populations are presented and summarised.

  15. Evaluation of bioaccumulation kinetics of gold nanorods in vital mammalian organs by means of total reflection X-ray fluorescence spectrometry.

    PubMed

    Fernández-Ruiz, Ramón; Redrejo, María Jesús; Friedrich, Eberhardt Josué; Ramos, Milagros; Fernández, Tamara

    2014-08-05

    This work presents the first application of total-reflection X-ray fluorescence (TXRF) spectrometry, a new and powerful alternative analytical method, to evaluation of the bioaccumulation kinetics of gold nanorods (GNRs) in various tissues upon intravenous administration in mice. The analytical parameters for developed methodology by TXRF were evaluated by means of the parallel analysis of bovine liver certified reference material samples (BCR-185R) doped with 10 μg/g gold. The average values (n = 5) achieved for gold measurements in lyophilized tissue weight were as follows: recovery 99.7%, expanded uncertainty (k = 2) 7%, repeatability 1.7%, detection limit 112 ng/g, and quantification limit 370 ng/g. The GNR bioaccumulation kinetics was analyzed in several vital mammalian organs such as liver, spleen, brain, and lung at different times. Additionally, urine samples were analyzed to study the kinetics of elimination of the GNRs by this excretion route. The main achievement was clearly differentiating two kinds of behaviors. GNRs were quickly bioaccumulated by highly vascular filtration organs such as liver and spleen, while GNRs do not show a bioaccumulation rates in brain and lung for the period of time investigated. In parallel, urine also shows a lack of GNR accumulation. TXRF has proven to be a powerful, versatile, and precise analytical technique for the evaluation of GNRs content in biological systems and, in a more general way, for any kind of metallic nanoparticles.

  16. A simple method for the multi-elemental analysis of organic fertilizer by slurry sampling and total reflection X-ray fluorescence.

    PubMed

    Resende, Luciene V; Nascentes, Clésia C

    2016-01-15

    A simple and fast method for the multi-elemental determination of 18 inorganic constituents (P, S, Cl, K, Ca, Ti, Cr, V, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Ba and Pb) in organic fertilizers employing slurry sampling and total reflection X-ray fluorescence (TXRF) is presented. A 2(3) factorial design with a central point was employed to optimize the slurry sampling procedure. The internal standard and instrumental conditions were optimized by univariate studies. The selectivity of the method to determining Se, As, Pb, Cr, Ni and Cd was assessed. The accuracy was evaluated by the analysis of four standard reference materials (SRM). The recoveries varied from 72% to 114%. For most of the elements, good agreement was achieved between the certified value and the value measured in the SRM. The relative standard deviation (RSD %) ranged from 0.5% to 14%. The evaluated method was applied to the determination of analytes in the press cake of palm, castor, curcas, sunflower, fodder turnip, white lupin, rapeseed and pequi, and their potential to be used as organic fertilizer was evaluated in accordance with Brazilian legislation. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Simulations of the quart (101-bar1)/water interface: A comparison of classical force fields, ab initi molecular dynamics, and x-ray reflectivity experiments.

    SciTech Connect

    Skelton, Adam; Fenter, Paul; Kubicki, James D.; Wesolowski, David J; Cummings, Peter T

    2011-01-01

    Classical molecular dynamics (CMD) simulations of the (1011) surface of quartz interacting with bulk liquid water are performed using three different classical force fields, Lopes et al., ClayFF, and CHARMM water contact angle (CWCA), and compared to ab initio molecular dynamics (AIMD) and X-ray reflectivity (XR) results. The axial densities of the water and surface atoms normal to the surface are calculated and compared to previous XR experiments. Favorable agreement is shown for all the force fields with respect to the position of the water atoms. Analyses such as the radial distribution functions between water and hydroxyl atoms and the average cosine of the angle between the water dipole vector and the normal of the surface are also calculated for each force field. Significant differences are found between the different force fields from such analyses, indicating differing descriptions of the structured water in the near vicinity of the surface. AIMD simulations are also performed to obtain the water and hydroxyl structure for comparison among the predictions of the three classical force fields to better understand which force field is most accurate. It is shown that ClayFF exhibits the best agreement with the AIMD simulations for water hydroxyl radial distribution functions, suggesting that ClayFF treats the hydrogen bonding more accurately.

  18. Room temperature trapping of stibine and bismuthine onto quartz substrates coated with nanostructured palladium for total reflection X-ray fluorescence analysis

    NASA Astrophysics Data System (ADS)

    Romero, Vanesa; Costas-Mora, Isabel; Lavilla, Isela; Bendicho, Carlos

    2015-05-01

    In this work, a novel method for determining Sb and Bi based on the trapping of their covalent hydrides onto quartz reflectors coated with immobilized palladium nanoparticles (Pd NPs) followed by total reflection X-ray fluorescence (TXRF) analysis is proposed. Pd NPs were synthesized by chemical reduction of the metal precursor using a mixture of water:ethanol as mild reducing agent. Silanization using 3-mercaptopropyltrimethoxysilane (MPTMS) was performed for the immobilization of Pd NPs onto the quartz substrates. Volatile hydrides (stibine and bismuthine) generated by means of a continuous flow system were flushed onto the immobilized Pd NPs and retained by catalytic decomposition. As a result of the high catalytic activity of the nanostructured film, trapping can be performed at ambient temperature with good efficiency. Limits of detection (LODs) were 2.3 and 0.70 μg L- 1 for Sb and Bi, respectively. Enrichment factors of 534 and 192 were obtained for Sb and Bi, respectively. The new method was applied for the analysis of several matrices (milk, soil, sediment, cutaneous powder). Recoveries were in the range of 98.4-101% for both elements with a relative standard deviation of 2.5% (N = 5).

  19. Study on trace elements behaviour in cancerous and healthy tissues of colon, breast and stomach: Total reflection X-ray fluorescence applications

    NASA Astrophysics Data System (ADS)

    Magalhães, T.; Carvalho, M. L.; Von Bohlen, A.; Becker, M.

    2010-06-01

    In this work Total-reflection X-ray fluorescence (TXRF) was used to analyse healthy and cancerous tissues of the same individual along several contiguous thin sections of each tissue. Thirty two samples (16 pairs) of breast tissue, 30 samples (15 pairs) of intestine tissue and 10 samples (5 pairs) of stomach tissue were analysed. The samples were obtained in Civil Hospitals of Germany (Dortmund) and Portugal (Lisbon). The elemental distribution of P, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr and Pb in these samples was studied. Descriptive statistics based on bar graphics and hypotheses tests and also an automatic classification based on hierarchical grouping analysis was used for the several analysed tissues. It was shown that the behaviour of the elements is tissue dependent. Some elements, like P and K exhibit the same behaviour in all the analysed tissue types. They have increased concentrations in all cancerous tissues. Unlike, other elements like Br show completely different behaviour depending on the tissue: similar concentration in healthy and cancerous stomach, decreased levels in colon cancerous tissues and enhanced concentrations in breast was observed. Moreover cancer tissues present decreased Se concentrations on colon and increased on breast.

  20. Method and mechanism of vapor phase treatment-total reflection X-ray fluorescence for trace element analysis on silicon wafer surface

    NASA Astrophysics Data System (ADS)

    Takahara, Hikari; Mori, Yoshihiro; Shimazaki, Ayako; Gohshi, Yohichi

    2010-12-01

    Vapor phase treatment (VPT) is a pretreatment with hydrofluoric acid vapor to raise the sensitivity of total reflection X-ray fluorescence spectroscopy (TXRF) for trace metal analysis on silicon wafers. The International Organization for Standardization/Technical Committee 201/Working Group 2 (ISO/TC201/WG2) has been investigating the method to analyze 10 9 atoms/cm 2 level of metallic contamination on the silicon wafer surface. Though VPT can enhance the TXRF signal intensity from the metallic contamination, it has turned out that the magnitude of the enhancement varies with the type of methods and the process conditions. In this study, approaches to increase TXRF intensity by VPT are investigated using a fuming chamber in an automated VPD instrument. Higher signal intensity can be obtained when condensation is formed on the sample surface in a humidifying atmosphere and with a decreasing stage temperature. Surface observations with SEM and AFM show that particles with ~ 4 μm in diameter are formed and unexpectedly they are dented from the top surface level.

  1. Headspace thin-film microextraction onto graphene membranes for specific detection of methyl(cyclopentadienyl)-tricarbonyl manganese in water samples by total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Romero, V.; Costas-Mora, I.; Lavilla, I.; Bendicho, C.

    2016-12-01

    In this work, a novel analytical approach for determining methyl(cyclopentadienyl)-tricarbonyl (MMT) by total reflection X-ray fluorescence (TXRF) based on its trapping onto unmodified graphene membranes is described. Graphene membranes were synthesized by mild-thermal reduction of graphene oxide following drop-casting onto a glass substrate. High flexible and easy-to-handle graphene membranes with 10 mm diameter were obtained. In order to use the as-prepared membranes as extraction phases for headspace thin-solid film microextraction of MMT, they were fitted to quartz reflectors and placed onto the top of the glass vial containing the sample. Reflectors containing graphene membranes were directly used as sample carriers for TXRF analysis. Different parameters involved in the microextraction step were optimized in order to obtain the best performance. Detection and quantification limits were 18 and 60 ng L- 1 MMT, respectively. An enrichment factor of 265 was obtained. The method was successfully applied for the specific detection of MMT in different water samples and a certified reference material e.g., NWTM-27.2 fortified lake water. A recovery study was carried out on spiked water samples showing recoveries in the range 98-104% with a relative standard deviation of 4% (N = 5). In addition, speciation of manganese, i.e. MMT and Mn(II),in water samples can be accomplished since only volatile MMT is transferred to the headspace and retained onto graphene membranes.

  2. Surface Charge of the Calcite (104) Terrace Measured by Rb+ Adsorption in Aqueous Solutions Using Resonant Anomalous X-ray Reflectivity

    SciTech Connect

    Lee, Sang Soo; Heberling, Frank; Sturchio, Neil C.; Eng, Peter J.; Fenter, Paul

    2016-07-21

    Adsorption of Rb+ on the (104) plane of single crystal calcite was investigated to estimate the charge of the ionic crystal calcite – water interface. The adsorbed Rb+ coverage was quantified as a function of Rb concentration (1 – 100 mM) in calcite-saturated solutions at pH 8.3 by using in-situ resonant anomalous X-ray reflectivity in transmission cell geometry. The Rb+ coverages for all solution conditions were small with the maximum ion coverage (Γmax) of 0.12(4) Rb+/nm2 estimated by the best-fit Langmuir isotherm model. This result provides an estimate of the upper limit to the effective surface charge density of about –0.02 C/m2 considering that any Rb+ adsorption to the terrace plane is likely induced by electrostatic attraction. This charge density is significantly lower (by a factor of ≥10) than those estimated from macroscopic measurements, implying that any excess charge likely originates from surface defects.

  3. Seasonal determination of trace and ultra-trace content in Macrocystis pyrifera from San Jorge Gulf (Patagonia) by Total Reflection X-ray Fluorescence

    NASA Astrophysics Data System (ADS)

    Salomone, Vanesa N.; Riera, Marina; Cerchietti, Luciana; Custo, Graciela; Muniain, Claudia

    2017-05-01

    Seaweed have a great capacity to accumulate heavy metals in their tissues. The chemical characterization of seaweed is important due to their use in environmental monitoring and human or animal food. The aim of the present study was to evaluate the multi-elemental composition of seaweed from San Jorge Gulf (Patagonia, Argentina) by Total Reflection X-ray Fluorescence (TXRF). The elements As, Br, Cu, Cr, Fe, Mn, Ni, Pb, Rb, Sr, V and Zn were seasonally analyzed and quantified in blades of Macrocystis pyrifera. TXRF showed to be a suitable technique for simultaneous multi-element analysis in this kind of samples. The results revealed seasonal variations in the chemical content for some elements; arsenic content was maximum in summer and autumn, iron concentration increased to the winter and zinc concentration was maximum in autumn. The sum of principal micronutrients (Fe + Zn + Mn + Cu) varied between 114 and 171 mg k- 1 g dw. The total As concentration ranged between 36 and 66 mg kg- 1. Lead, nickel and copper were not detected.

  4. Whole-surface analysis of semiconductor wafers by accumulating short-time mapping data of total-reflection X-ray fluorescence spectrometry.

    PubMed

    Mori, Yoshihiro; Uemura, Kenichi; Lizuka, Yoshinori

    2002-03-01

    Total-reflection X-ray fluorescence (TXRF) spectrometry with no chemical preconcentration, often called "straight-TXRF", is now widely used in the semiconductor industry. The small detection area of TXRF enablesmapping measurement of contamination of the semiconductor surface, which is very useful in process characterization. However, the small detection area had been believed to limit rapid whole-surface analysis. Contrary to this general understanding, in this study we demonstrated that a new method, called "sweeping-TXRF", which is essentially short-time multipoint mapping by straight-TXRF, can rapidly provide an average concentration. A considerable problem of this method is the contribution of errors in glancing angle and areal element distribution to the fluorescence. Using statistics, we examined the errors and demonstrated that most of them are canceled and are not significant in actual semiconductor applications. The results of an experiment that measured localized 6 x 10(10) atoms cm(-2) nickel contamination supported the above conclusion. Applying sweeping-TXRF to existing TXRF instruments is easy-the only requirement is a small software modification. We believe that sweeping-TXRF will be utilized for rapid whole-surface analysis in many fields, especially in the semiconductor industry.

  5. Determination of nickel, copper, zinc and lead in human scalp hair in Syrian occupationally exposed workers by total reflection X-ray fluorescence.

    PubMed

    Khuder, A; Bakir, M A; Hasan, R; Mohammad, A

    2008-08-01

    The concentrations of Ni, Cu, Zn, and Pb in human scalp hair of 281 individuals working in 10 Syrian industrial plants were determined using co-precipitation by ammoniumpyrolidinedithiocarbamate (APDC) method for total reflection X-ray fluorescence (TXRF) analysis. The results were compared to data obtained for a control group consisted of individuals working at the Syrian Atomic Energy Commission and also to data reported in the literature. The results given by the group of workers in battery plant showed that Pb concentration in human scalp hair samples were higher than those for control group, while some abnormal concentrations were obtained for Cu, Zn and Ni in cables, printing and battery plants, respectively. Normal concentrations of these elements were obtained for hair workers in olive oil, power stations, textile, and iron industrial plants. The relationships of Pb-Pb/Ni and Cu-Cu/Ni were plotted with correlation coefficients of 0.9937 and 0.9014, respectively. In general, the results showed that, the workers who were occupationally exposed to battery industrial pollution are at risk, followed by individuals in printing and cables industries, while the rest of workers in other industries are considered occupationally unexposed.

  6. Analysis of some chosen elements of cerebrospinal fluid and serum in amyotrophic lateral sclerosis patients by total reflection X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Ostachowicz, B.; Lankosz, M.; Tomik, B.; Adamek, D.; Wobrauschek, P.; Streli, C.; Kregsamer, P.

    2006-11-01

    Trace elements play an important role in the human central nervous system. Significant variations of the concentration of trace elements in body fluids may occur in neurodegenerative diseases. In the present work an investigation of the elemental composition of the serum, and the cerebrospinal fluid in amyotrophic lateral sclerosis patients and a control group was performed. For the analysis of the body fluids Total reflection X-ray Fluorescence (TXRF) spectrometry was used. The samples were taken during routine diagnostic procedures. Na, Mg, Cl, K, Ca, Cu, Zn, and Br were determined in both fluids. In order to validate the results of analysis a serum standard reference material was measured. A t-test was applied to check if the mean concentrations of the elements are different for ALS and the control group. For the serum samples higher values for Br were found in the ALS group, for the cerebrospinal fluid lower values of Na, Mg and Zn as well as higher Ca values were found in the ALS group compared to the control group.

  7. Self-assembly mechanism of nanoparticles of Ni-based Prussian Blue analogues at the air/liquid interface: a synchrotron X-ray reflectivity study.

    PubMed

    Giner-Casares, Juan J; Clemente-León, Miguel; Coronado, Eugenio; Brezesinski, Gerald

    2015-08-24

    Prussian Blue analogue (PBA) nanoparticles can be self-assembled at air/liquid interfaces to build novel materials with interesting magnetic features. Herein, we study the influence of the size of PBA Cs0.4 Ni[Cr(CN)6 ]0.9 and K0.25 Ni[Fe(CN)6 ]0.75 nanoparticles on the self-assembly behavior by synchrotron X-ray reflectivity. Both nanoparticles show similar Z-potential values. The phospholipid dipalmitoylphosphatidylcholine and the amino surfactant dimethyldioctadecylammonium have been used as Langmuir monolayers to anchor the PBA nanoparticles and study the interplay of forces directing the self-assembly of the nanoparticles at the surfactant/liquid interface. Whereas Cs0.4 Ni[Cr(CN)6 ]0.9 nanoparticles with a diameter of 8 nm form an incomplete layer at the surfactant/water interface, the larger K0.25 Ni[Fe(CN)6 ]0.75 nanoparticles with a diameter of 20 nm generate complete layers that can be stacked to one another. The size of the PBA nanoparticles is the main parameter determining the final arrangement at the air/liquid interface, due to the different extent of interparticle interaction. This study aims at the rationale design of PBA nanoparticles for an effective interfacial self-assembly, ultimately leading to functional materials.

  8. Analysis of total and dissolved heavy metals in surface water of a Mexican polluted river by total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Zarazua, G.; Ávila-Pérez, P.; Tejeda, S.; Barcelo-Quintal, I.; Martínez, T.

    2006-11-01

    The present area of study is located in the Upper Course of the Lerma River (UCLR). The Lerma is one of the most important rivers of Mexico, where it drains highly populated and industrialized regions. The aim of the present study is to determine the heavy metal concentration of Cr, Mn, Fe, Cu and Pb in dissolved and total phases of the UCLR by means of Total Reflection X-ray Fluorescence Spectrometry (TXRF). The surface water samples were collected at 8 sites distributed following the stream flow direction of the river. Four sampling campaigns were carried out in each site in a 1-year period. A sample preparation method was applied in order to obtain the total and dissolved fraction and to destroy the organic matter. The total heavy metal average concentration decrease in the following order: Fe (2566 μg/L) > Mn (300 μg/L) > Cu (66 μg/L) > Cr (21 μg/L) > Pb (15 μg/L). In general, the heavy metal concentrations in water of the UCLR are below the maximum permissible limits.

  9. Annealing Behavior of Atomic Layer Deposited HfO2 Films Studied by Synchrotron X-ray Reflectivity and Grazing Incidence Small Angle Scattering

    SciTech Connect

    Green, M.; Allen, A; Jordan-Sweet, J; Ilavsky, J

    2009-01-01

    New results are presented for the annealing behavior of ultrathin complementary-metal-oxide-semiconductor (CMOS) gate dielectric HfO{sub 2} films grown by atomic layer deposition (ALD). A series of ALD HfO{sub 2} dielectric films has been studied by a combination of x-ray reflectivity (XRR) and grazing-incidence small-angle x-ray scattering (GISAXS) measurements. By using these techniques together, we have shown that the surface, interfaces, and internal structure of thin ALD films can be characterized with unprecedented sensitivity. Changes in film thickness, film roughness, or diffuseness of the film/substrate interface as measured by XRR are correlated with the corresponding changes in the internal film nanostructure, as measured by GISAXS. Although the films are dense, an internal film structure is shown to exist, attributed primarily to {approx} 2 nm 'missing island' porosity features close to the substrate; these are most likely associated with coalescence defects as a result of initial ALD growth, as they are not observed in the upper regions of the film. Some 8-9 nm heterogeneities are also present, which may indicate a widespread modulation in the film density pervading the entire film volume, and which likely also give rise to surface roughness. Comparison of the data between different scattering geometries and among a carefully designed sequence of samples has enabled important insights to be derived for the annealing behavior of the ALD HfO{sub 2} films. The main effects of single, brief, high temperature excursions to above 900C are to anneal out some of the fine voids and reduce the mean roughness and interfacial diffuseness of the film. These changes are indicative of densification. However, depending on the film thickness, the annealing behavior at temperatures between 650 and 800C is quite different for single excursion and cyclic anneals. Particularly for thin, just-coalesced films, XRR indicates marked increases in the film thickness and in the

  10. X-Ray Data from the X-Ray Data Booklet Online

    DOE Data Explorer

    Thompson, Albert C.; Attwood, David T.; Gullikson, Eric M.; Howells, Malcolm R.; Kortright, Jeffrey B.; Robinson, Arthur L.; Underwood, James H.; Kim, Kwang-Je; Kirz, Janos; Lindau, Ingolf; Pianetta, Piero; Winick, Herman; Williams, Gwyn P.; Scofield, James H.

    The original X-Ray Data Booklet, published in 1985, became a classic reference source. The online version has been significantly revised and updated to reflect today's science. Hundreds of pages of authoritative data provide the x-ray properties of elements, information on synchrotron radiation, scattering processes, optics and detectors, and other related calculations, formulas, and data tables.

  11. Clocking femtosecond X rays.

    PubMed

    Cavalieri, A L; Fritz, D M; Lee, S H; Bucksbaum, P H; Reis, D A; Rudati, J; Mills, D M; Fuoss, P H; Stephenson, G B; Kao, C C; Siddons, D P; Lowney, D P; Macphee, A G; Weinstein, D; Falcone, R W; Pahl, R; Als-Nielsen, J; Blome, C; Düsterer, S; Ischebeck, R; Schlarb, H; Schulte-Schrepping, H; Tschentscher, Th; Schneider, J; Hignette, O; Sette, F; Sokolowski-Tinten, K; Chapman, H N; Lee, R W; Hansen, T N; Synnergren, O; Larsson, J; Techert, S; Sheppard, J; Wark, J S; Bergh, M; Caleman, C; Huldt, G; van der Spoel, D; Timneanu, N; Hajdu, J; Akre, R A; Bong, E; Emma, P; Krejcik, P; Arthur, J; Brennan, S; Gaffney, K J; Lindenberg, A M; Luening, K; Hastings, J B

    2005-03-25

    Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms.

  12. Lacquer polishing of X-ray optics

    NASA Technical Reports Server (NTRS)

    Catura, R. C.; Joki, E. G.; Roethig, D. T.; Brookover, W. J.

    1987-01-01

    Techniques for polishing figured X-ray optics by a lacquer-coating process are described. This acrylic lacquer coating has been applied with an optical quality of an eighth-wave in red light and very effectively covers surface roughness with spatial wavelengths less than about 0.2 mm. Tungsten films have been deposited on the lacquer coatings to provide highly efficient X-ray reflectivity.

  13. History of Chandra X-Ray Observatory

    NASA Image and Video Library

    2001-01-10

    This Chandra image, the first x-ray image ever made of Venus, shows a half crescent due to the relative orientation of the Sun, Earth, and Venus. The x-rays are produced by fluorescent radiation from oxygen and other atoms in the atmosphere between 120 and 140 kilometers above the surface of the planet. In contrast, the optical light from Venus is caused by the reflection from clouds 50 to 70 kilometers above the surface.

  14. X-ray reflectivity investigations of two-dimensional assemblies of C-cadherins: First steps in structural and functional studies

    NASA Astrophysics Data System (ADS)

    Martel, L.; Johnson, C.; Boutet, S.; Al-Kurdi, R.; Konovalov, O.; Robinson, I.; Leckband, D.; Legrand, J.-F.

    2002-07-01

    Cadherins are transmembrane proteins involved in cell adhesion. They play a major role in recognition and adhesion between adjacent cells via calcium dependent interactions. Our studies aim at determining the laws of assembly of cadherins and locating the adhesive interactions along the proteins, starting from low-resolution structures obtained by X-rays grazing incidence reflectivity. We have realized monolayers of the extracellular fragment of C-cadherin of the frog Xenopus, anchored to nickel chelating lipids at the water surface. From X-ray reflectivity measurements carried out at ESRF, we have elaborated profiles of the electron density of the proteins along their axis with 0.9 nm resolution. We have studied their adhesive behaviour with high and low calcium concentrations and we show an ordering of the protein above I mM of calcium. We present an attempt to locate the binding of a short fragment of cadherin on the full-length protein. The complementarities of our results with those of biochemical studies should enable us to comprehend further cellular adhesion mechanisms. Les cadhérines sont des protéines transmembranaires impliquées dans l'adhésion cellulaire. Elles jouent un rôle majeur dans la reconnaissance et l'adhésion entre cellules contiguës via des interactions dépendantes du calcium. Nos études visent à déterminer les lois d'assemblage des cadhérines et à localiser les interactions adhésives le long des protéines, à partir de structures à basse résolution obtenues par réflectivité des rayons X en incidence rasante. Nous avons réalisé des monocouches de fragments extracellulaires de C-cadhérine de la grenouille Xenopus, ancrés à des lipides chélateurs d'un ion nickel déposés à la surface de l'eau. A partir de mesures de réflectivité des rayons X effectuées à l'ESRF, nous avons déterminé des profils de densité électronique des protéines le long de leur axe avec une résolution de 0.9 nm. Nous avons étudié leur

  15. X-ray fluorescence experiment

    NASA Technical Reports Server (NTRS)

    Adler, I.; Trombka, J. I.; Gerard, J.; Schmadebeck, R.; Lowman, P.; Blodgett, H.; Yin, L.; Eller, E.; Lamothe, R.; Gorenstein, P.

    1972-01-01

    The preliminary results from the Sco X-1 and Cyg X-1 obtained from the Apollo 15 X-ray detector data are presented along with preliminary results of the X-ray fluorescence spectrometric data of the lunar surface composition. The production of the characteristic X-rays following the interaction of solar X-rays with the lunar surface is described along with the X-ray spectrometer. Preliminary analyses of the astronomical X-ray observation and the X-ray fluorescence data are presented.

  16. Application of total-reflection X-ray fluorescence spectrometry and high-performance liquid chromatography for the chemical characterization of xylem saps of nickel contaminated cucumber plants

    NASA Astrophysics Data System (ADS)

    Mihucz, Victor G.; Tatár, Eniko; Varga, Anita; Záray, Gyula; Cseh, Edit

    2001-11-01

    Total-reflection X-ray fluorescence (TXRF) spectrometry, reversed-phase (RP) and size-exclusion (SE) high-performance liquid chromatography (HPLC) methods were applied for the characterization of low-volume xylem sap of control and nickel contaminated cucumber plants growing in hydroponics containing urea as the sole nitrogen source. In these saps collected for 1 h, Ca, K, Fe, Mn, Ni, Zn, as well as malic, citric and fumaric acids were determined. The SEC measurements showed that macromolecules were not detectable in the samples. Nickel contamination had minimum impact on the organic acid transport, however, the transport of Zn, K and Fe was reduced by 50, 22 and 11%, respectively. This observation supports the results of our earlier experiments when nitrate ions were used as the sole nitrogen form. At the same time, the fresh root weight and the volume of the collected xylem sap increased by 36 and 85%, respectively. Therefore, nickel addition seemed to decrease the urea toxicity of the plants. By pooling the eluting fractions of the SEC column, which were 10-fold concentrated by freeze-drying, the series of the resulted samples were analyzed by the TXRF spectrometry and RP-HPLC. The three organic acids could be identified in only one of the fractions, which contained Fe and, in the case of the contaminated plants, Ni in detectable concentration. However, considerable parts of these two elements and Mn, as well as practically the total amounts of Cu may be transported by unidentified organic compounds in the xylem.

  17. Evaluation of the protein concentration in enzymes via determination of sulfur by total reflection X-ray fluorescence spectrometry — limitations of the method

    NASA Astrophysics Data System (ADS)

    Mertens, M.; Rittmeyer, C.; Kolbesen, B. O.

    2001-11-01

    Total reflection X-ray fluorescence spectrometry (TXRF) offers many advantages for the identification of trace elements in biological samples like proteins, enzymes, tissues or plants. Because of difficult and time consuming isolations and cleaning procedures enzyme samples are often available in small amounts only. Using TXRF without any preliminary treatment, a 'screening' of such samples to determine the element composition is of interest and importance. Transition metals like Fe, Ni, Cu, Mo and the alkaline earth metal Ca may be determined with high accuracy. A further aspect of the investigation of enzymes is the simple and simultaneous determination of light elements. Sulfur, especially, is of interest. This element is a component of two amino acids, methionine and cysteine, and of iron-sulfur clusters and may be used for easy and simultaneous calculation of the protein concentration. Hence quantitative determination of sulfur by TXRF allows a cross-check regarding of conventional quantitative determination of protein concentration by, e.g. the Lowry method. On the basis of two selected enzymes of different origins and molecular weights this paper will demonstrate the influence of bio-organic matrix and different buffer media on sulfur determination by TXRF. The influence of layer thicknesses of the dry residues and absorption or scattering effects will be discussed. The results indicate that in enzymes with low molecular weights and minor amounts of buffer components a reliable determination of sulfur is possible. By contrast, for enzymes stored in higher buffer concentrations poorer results are given on account of the matrix effects described.

  18. Interaction of Isophorone with Pd(111): A Combination of Infrared Reflection-Absorption Spectroscopy, Near-Edge X-ray Absorption Fine Structure, and Density Functional Theory Studies.

    PubMed

    Dostert, Karl-Heinz; O'Brien, Casey P; Riedel, Wiebke; Savara, Aditya; Liu, Wei; Oehzelt, Martin; Tkatchenko, Alexandre; Schauermann, Swetlana

    2014-12-04

    Atomistic level understanding of interaction of α,β-unsaturated carbonyls with late transition metals is a key prerequisite for rational design of new catalytic materials with the desired selectivity toward C=C or C=O bond hydrogenation. The interaction of this class of compounds with transition metals was investigated on α,β-unsaturated ketone isophorone on Pd(111) as a prototypical system. In this study, infrared reflection-absorption spectroscopy (IRAS), near-edge X-ray absorption fine structure (NEXAFS) experiments, and density functional theory calculations including van der Waals interactions (DFT+vdW) were combined to obtain detailed information on the binding of isophorone to palladium at different coverages and on the effect of preadsorbed hydrogen on the binding and adsorption geometry. According to these experimental observations and the results of theoretical calculations, isophorone adsorbs on Pd(111) in a flat-lying geometry at low coverages. With increasing coverage, both C=C and C=O bonds of isophorone tilt with respect to the surface plane. The tilting is considerably more pronounced for the C=C bond on the pristine Pd(111) surface, indicating a prominent perturbation and structural distortion of the conjugated π system upon interaction with Pd. Preadsorbed hydrogen leads to higher tilting angles of both π bonds, which points to much weaker interaction of isophorone with hydrogen-precovered Pd and suggests the conservation of the in-plane geometry of the conjugated π system. The results of the DFT+vdW calculations provide further insights into the perturbation of the molecular structure of isophorone on Pd(111).

  19. DYNAMICS OF X-RAY-EMITTING EJECTA IN THE OXYGEN-RICH SUPERNOVA REMNANT PUPPIS A REVEALED BY THE XMM-NEWTON REFLECTION GRATING SPECTROMETER

    SciTech Connect

    Katsuda, Satoru; Tamagawa, Toru; Ohira, Yutaka; Mori, Koji; Tsunemi, Hiroshi; Koyama, Katsuji; Uchida, Hiroyuki

    2013-05-10

    Using the unprecedented spectral resolution of the reflection grating spectrometer (RGS) on board XMM-Newton, we reveal dynamics of X-ray-emitting ejecta in the oxygen-rich supernova remnant Puppis A. The RGS spectrum shows prominent K-shell lines, including O VII He{alpha} forbidden and resonance, O VIII Ly{alpha}, O VIII Ly{beta}, and Ne IX He{alpha} resonance, from an ejecta knot positionally coincident with an optical oxygen-rich filament (the so-called {Omega} filament) in the northeast of the remnant. We find that the line centroids are blueshifted by 1480 {+-} 140 {+-} 60 km s{sup -1} (the first and second term errors are measurement and calibration uncertainties, respectively), which is fully consistent with that of the optical {Omega} filament. Line broadening at 654 eV (corresponding to O VIII Ly{alpha}) is obtained to be {sigma} {approx}< 0.9 eV, indicating an oxygen temperature of {approx}< 30 keV. Analysis of XMM-Newton MOS spectra shows an electron temperature of {approx}0.8 keV and an ionization timescale of {approx}2 Multiplication-Sign 10{sup 10} cm{sup -3} s. We show that the oxygen and electron temperatures as well as the ionization timescale can be reconciled if the ejecta knot was heated by a collisionless shock whose velocity is {approx}600-1200 km s{sup -1} and was subsequently equilibrated due to Coulomb interactions. The RGS spectrum also shows relatively weak K-shell lines of another ejecta feature located near the northeastern edge of the remnant, from which we measure redward Doppler velocities of 650 {+-} 70 {+-} 60 km s{sup -1}.

  20. Determination of metallic contaminants on Ge wafers using direct- and droplet sandwich etch-total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Hellin, D.; Bearda, T.; Zhao, C.; Raskin, G.; Mertens, P. W.; De Gendt, S.; Heyns, M. M.; Vinckier, C.

    2003-12-01

    An analysis methodology for the metallic contamination control of Ge wafer substrates has been developed and evaluated for six elements (K, Ca, Cr, Fe, Ni and Zn). Detection limits (DL) of Direct-total reflection X-ray fluorescence spectrometry (D-TXRF) analysis on Ge wafers have been determined and found to be at the E10 at/cm 2 level. The values have been found to be a factor between 1 and 3 higher than on Si wafers, exclusively caused by differences in the background intensity. Additionally, a preconcentration procedure based on the Droplet sandwich etch (DSE) method has been developed. This method relies on the transfer of the surface and subsurface contaminants from the wafer to the liquid phase by wet chemical etching. Application of the DSE method on reference Ge wafers followed by analysis of the etch liquid by TXRF resulted in recovery rates (RR) of 40%. In an optimization study, it was found that the main DSE method parameters had limited influence on the RR. However, a detection efficiency study clearly demonstrated an underestimation by the TXRF analysis. An independent analysis for Ca, Cr, Fe and Zn by GF-AAS resulted in RR varying at approximately 100%. By internal standardization with the element La for the TXRF analysis, recovery rates could be increased to the 60% level. This underestimation by TXRF may find an origin in a matrix effect caused by the Ge etch products. By application of the developed DSE-TXRF method, DL at the E9 at/cm 2 level could be realized, with values, which are at least one order of magnitude lower compared to the DL of D-TXRF on Ge wafers.

  1. Mechanism of Interaction Between the General Anesthetic Halothane and a Model Ion Channel Protein, I: Structural Investigations via X-Ray Reflectivity from Langmuir Monolayers

    SciTech Connect

    Strzalka, J.; Liu, J; Tronin, A; Churbanova, I; Johansson, J; Blasie, J

    2009-01-01

    We previously reported the synthesis and structural characterization of a model membrane protein comprised of an amphiphilic 4-helix bundle peptide with a hydrophobic domain based on a synthetic ion channel and a hydrophilic domain with designed cavities for binding the general anesthetic halothane. In this work, we synthesized an improved version of this halothane-binding amphiphilic peptide with only a single cavity and an otherwise identical control peptide with no such cavity, and applied x-ray reflectivity to monolayers of these peptides to probe the distribution of halothane along the length of the core of the 4-helix bundle as a function of the concentration of halothane. At the moderate concentrations achieved in this study, approximately three molecules of halothane were found to be localized within a broad symmetric unimodal distribution centered about the designed cavity. At the lowest concentration achieved, of approximately one molecule per bundle, the halothane distribution became narrower and more peaked due to a component of {approx}19Angstroms width centered about the designed cavity. At higher concentrations, approximately six to seven molecules were found to be uniformly distributed along the length of the bundle, corresponding to approximately one molecule per heptad. Monolayers of the control peptide showed only the latter behavior, namely a uniform distribution along the length of the bundle irrespective of the halothane concentration over this range. The results provide insight into the nature of such weak binding when the dissociation constant is in the mM regime, relevant for clinical applications of anesthesia. They also demonstrate the suitability of both the model system and the experimental technique for additional work on the mechanism of general anesthesia, some of it presented in the companion parts II and III under this title.

  2. Reflective optics for effective collection of x-ray and EUV radiation: use for creation of photoionized plasmas and detection of weak signals

    NASA Astrophysics Data System (ADS)

    Bartnik, A.; Skrzeczanowski, W.; Wachulak, P.; Saber, I.; Fiedorowicz, H.; Fok, T.; Wegrzyński, Ł.

    2017-05-01

    In this work different kinds of reflective optical systems were used for creation and investigation of low temperature, photoionized plasmas. The plasmas were created in gases, irradiated with a focused beam of extreme ultraviolet (EUV) or soft X-ray (SXR) radiation, from laser-plasma sources employing 10 Hz Nd:YAG laser systems (0.8 J/ 4 ns and 10 J/ 1-10 ns). In both cases, the EUV radiation was focused using a gold-plated grazing incidence ellipsoidal collector in the wavelength range λ = 9÷70 nm or a gold-plated grazing incidence multifoil collector in the wavelength range λ = 5 ÷ 70 nm. Additionally, in case of the 10 J Nd:YAG laser with the pulse duration 1 ns, a paraboloidal collector optimized for the wavelength range λ >= 1 nm was employed. Different gases were injected into the vacuum chamber, perpendicularly to an optical axis of the irradiation system at the focal region, using an auxillary gas puff valve. Irradiation of the gases resulted in ionization and excitation of atoms/molecules. Spectra in SXR/EUV range were measured using a grazing incidence, flat-field spectrometer (McPherson Model 251), equipped with a 450 lines/mm toroidal grating or a home-made spectrograph based on the 5000 l/mm transmission grating. Optical spectra were recorded using the Echelle Spectra Analyzer ESA 4000. In all cases the most intense emission lines were assigned to singly charged ions, however, lines corresponding to ions with higher charge were also recorded. Based on spectral lines originating from ions electron temperature was estimated.

  3. Research of nested X-ray concentrator for future X-ray timing astronomy

    NASA Astrophysics Data System (ADS)

    Sheng, Lizhi; Zhao, Baosheng; Qiang, Pengfei; Liu, Duo

    2017-02-01

    X-ray grazing incidence optics are widely used in X-ray astronomy, especially for imaging payloads Wolter optics are the most workhorse. However, as there are two cascaded mirrors in Wolter type, the efficiency is quite low after two reflections. In this paper a kind of nested conical concentrator is developed with only one reflection to concentrate the X-ray photons and obtain the timing information. The mirror length is 200mm, the mirror foils cover from 38.8 to 100mm in diameter. D263T glass of 0.3mm thickness is used as mirror substrate with Iridium film deposited in order to improve the X-ray reflection. The D263T glass is slumped at 580°C with precisely machined and polished mold. 3D printed resin serves as upper mold for glass cutting. The quality of mirror substrate is mainly determined by the surface of forming mandrel. As the surface roughness is quite important for X-ray reflection, after deposition it is tested with interferometer and AFM, and the roughness is 0.6nm. Mirror integration based on visible light is built, and the conical mirrors are assembled and adjusted by real time monitoring for the focal point of visible light. With the monochromic X-ray source, the concentrator efficiency is tested as 38%@1.49keV, 20%@4.51keV. The focal point is Φ8.2mm in Xray, with 80% of its energy encircled in a 4mm width. This kind of X-ray concentrator could be used in X-ray navigation, X-ray communication and other X-ray timing astronomy.

  4. X-ray beam finder

    DOEpatents

    Gilbert, H.W.

    1983-06-16

    An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

  5. Neck x-ray

    MedlinePlus

    ... look at cervical vertebrae. These are the 7 bones of the spine in the neck. ... A neck x-ray can detect: Bone joint that is out of position (dislocation) Breathing in a foreign object Broken bone (fracture) Disk problems (disks ...

  6. Extremity x-ray

    MedlinePlus

    ... this test if you have signs of: A fracture Tumor Arthritis (inflammation of the joints) Normal Results The x-ray shows normal structures for the age of the person. What Abnormal Results Mean ... bone (fracture) Dislocated bone Osteomyelitis (infection) Arthritis Other conditions for ...

  7. Ion mobilities in diatomic gases: measurement versus prediction with non-specular scattering models.

    PubMed

    Larriba, Carlos; Hogan, Christopher J

    2013-05-16

    Ion/electrical mobility measurements of nanoparticles and polyatomic ions are typically linked to particle/ion physical properties through either application of the Stokes-Millikan relationship or comparison to mobilities predicted from polyatomic models, which assume that gas molecules scatter specularly and elastically from rigid structural models. However, there is a discrepancy between these approaches; when specular, elastic scattering models (i.e., elastic-hard-sphere scattering, EHSS) are applied to polyatomic models of nanometer-scale ions with finite-sized impinging gas molecules, predictions are in substantial disagreement with the Stokes-Millikan equation. To rectify this discrepancy, we developed and tested a new approach for mobility calculations using polyatomic models in which non-specular (diffuse) and inelastic gas-molecule scattering is considered. Two distinct semiempirical models of gas-molecule scattering from particle surfaces were considered. In the first, which has been traditionally invoked in the study of aerosol nanoparticles, 91% of collisions are diffuse and thermally accommodating, and 9% are specular and elastic. In the second, all collisions are considered to be diffuse and accommodating, but the average speed of the gas molecules reemitted from a particle surface is 8% lower than the mean thermal speed at the particle temperature. Both scattering models attempt to mimic exchange between translational, vibrational, and rotational modes of energy during collision, as would be expected during collision between a nonmonoatomic gas molecule and a nonfrozen particle surface. The mobility calculation procedure was applied considering both hard-sphere potentials between gas molecules and the atoms within a particle and the long-range ion-induced dipole (polarization) potential. Predictions were compared to previous measurements in air near room temperature of multiply charged poly(ethylene glycol) (PEG) ions, which range in morphology from

  8. Quasar x-ray spectra revisited

    NASA Technical Reports Server (NTRS)

    Shastri, P.; Wilkes, B. J.; Elvis, M.; Mcdowell, J.

    1992-01-01

    A sample of 45 quasars observed by the Imaging Proportional Counter (IPC) on the Einstein satellite is used to re-examine the relationship between the soft (0.2-3.5 keV) X-ray energy index and radio-loudness. We found the following: (1) the tendency for radio-loud quasars to have systematically flatter X-ray slopes than radio-quiet quasars (RQQ's) is confirmed with the soft X-ray excess having negligible effect; (2) there is a tendency for the flatness of the X-ray slope to correlate with radio core-dominance for radio-loud quasars, suggesting that a component of the X-ray emission is relativistically beamed; (3) for the RQQ's the soft X-ray slopes, with a mean of approximately 1.0, are consistent with the slopes found at higher energies (2-10 keV) although steeper than those observed for Seyfert 1 galaxies (also 2-10 keV) where the reflection model gives a good fit to the data; (4) the correlation of FeII emission line strength with X-ray energy index is confirmed for radio-quiet quasars using a subset of 18 quasars. The radio-loud quasars show no evidence for a correlation. This relation suggests a connection between the ionizing continuum and the line emission from the broad emission line region (BELR) of radio-quiet quasars, but in the opposite sense to that predicted by current photoionization models; and (5) the correlations of X-ray slope with radio core dominance and FeII equivalent width within the radio-loud and radio-quiet sub-classes respectively imply that the observed wide range of X-ray spectral slopes is real rather than due to the large measuring uncertainties for individual objects.

  9. Quasar X-ray spectra revisited

    NASA Technical Reports Server (NTRS)

    Shastri, P.; Wilkes, B. J.; Elvis, M.; Mcdowell, J.

    1993-01-01

    A sample of 45 quasars observed by the IPC on the Einstein satellite is used to reexamine the relationship of the soft X-ray energy index with radio properties and the optical Fe II emission. The tendency for radio-loud quasars to have systematically flatter X-ray energy indices than radio-quiet quasars is confirmed with the soft X-ray excess having negligible effect. There is a tendency for the flatness of the X-ray slope to correlate with radio core dominance for radio-loud quasars, suggesting that a component of the X-ray emission is relativistically beamed. For the radio-quiet quasars, the soft X-ray energy indices with a mean of about 1.0 are consistent with the indices found at higher energies, although steeper than those observed for Seyfert 1 galaxies where the reflection model gives a good fit to the data. The correlation of Fe II emission line strength with X-ray energy index is confirmed for radio-quiet quasars using a subset of 18 objects. The radio-loud quasars show no evidence for a correlation. This relation suggests a connection between the ionizing continuum and line emission from the broad emission-line region (BELR) of radio-quiet quasars, but in the opposite sense to that predicted by current photoionization models. The correlations of X-ray slope with radio core dominance and Fe II equivalent width within the radio-loud and radio-quiet subclasses, respectively, imply that the observed wide range of X-ray energy indices is real rather than due to the large measuring uncertainties for individual objects.

  10. Hard X-ray Laue monochromator

    NASA Astrophysics Data System (ADS)

    Kocharyan, V. R.; Gogolev, A. S.; Kiziridi, A. A.; Batranin, A. V.; Muradyan, T. R.

    2016-06-01

    Experimental studies of X-ray diffraction from reflecting atomic planes (10¯11) of X-cut quartz single crystal in Laue geometry influenced by the temperature gradient were carried out. It is shown that by using the temperature gradient it is possible to reflect a hard X- ray beam with photon energy near the 100 keV with high efficiency. It has been experimentally proved that the intensity of the reflected beam can be increased by more than order depending on the value of the temperature gradient.

  11. Determination of Fe(II) and Fe(III) in small samples by microbore ion chromatography and photometric, atomic absorption spectrometry and total-reflection X-ray fluorescence detection

    NASA Astrophysics Data System (ADS)

    Sinner, T.; Hoffmann, P.; Ortner, H. M.

    1993-02-01

    Iron(II) and iron(III) are determined after separation on an ion Chromatographie column by various detection systems. "On-line" detection was achieved by the use of a photometer with a flow cell of 0.8 μl; for "off-line" detection, graphite furnace atomic absorption spectrometry or total-reflection X-ray fluorescence were used. The applicability of the methods is shown for standard solutions and atmospheric samples. As a typical result, 50 μg/l of iron can be determined in a 10 μl sample with a nucrobore ion chromatograph-photometer and atomic absorption system and 40 μg/l of iron in a microbore ion chromatograph-total-reflection X-ray fluorescence combination.

  12. Planetary X ray experiment

    NASA Technical Reports Server (NTRS)

    Anderson, K. A.

    1972-01-01

    Design studies for an X-ray experiment using solid state detectors and for an experiment using a proportional counter for investigating Jovian and Saturnian magnetospheres are reported. Background counting rates through the forward aperture and leakage fluxes are discussed for each design. It is concluded that the best choice of instrument appears to have following the characteristics: (1) two separate multiwire proportional counters for redundancy; (2) passive collimation to restrict the field to about 5 deg, wiregrid modulation collimation to about 0.1 deg angular resolution; (3) no active shielding system around the counter body; and (4) light passive shielding around any portion of the counter body exposed to space to absorb most of the cosmic X-ray background.

  13. Size-fractionated sampling and chemical analysis by total-reflection X-ray fluorescence spectrometry of PMx in ambient air and emissions

    NASA Astrophysics Data System (ADS)

    John, A. C.; Kuhlbusch, T. A. J.; Fissan, H.; Schmidt, K.-G.

    2001-11-01

    PM 10 and PM 2.5 (PMx) have been recently introduced as new air quality standards in the EU (Council Directive 1999/30/EC) for particulate matter. Different estimates and measurements showed that the limit values for PM 10 will be exceeded at different locations in Europe, and thus measures will have to be taken to reduce PMx mass concentrations. Source apportionment has to be carried out, demanding comparable methods for ambient air and emission sampling and chemical analysis. Therefore, a special ambient-air sampler and a specially designed emission sampler have been developed. Total-reflection X-ray fluorescence analysis (TXRF) was used for multi-element analyses as a fast method with low detection limits. For ambient air measurements, a sampling unit was built, impacting particle size classes 10-2.5 μm and 2.5-1.0 μm directly onto TXRF sample carriers. An electrostatic precipitator (ESP) was used as back-up filter to also collect particles <1 μm directly onto the TXRF sample carriers. Air quality is affected by natural and anthropogenic sources, and the emissions of particles <10 μm and <2.5 μm, respectively, have to be determined to quantify their contributions to the so-called coarse (10-2.5 μm) and fine (<2.5 μm) particle modes in ambient air. For this, an in-stack particle sampling system was developed, according to the new ambient air quality standards and in view of subsequent analysis by TXRF. These newly developed samplers, in combination with TXRF analyses, were employed in field campaigns to prove the feasibility and capabilities of the approach. Ambient air data show the quantification of a wide spectrum of elements. From those concentrations, PMx ratios were calculated as an indicator for different sources of elements. Results useful for source apportionment are also the elemental day/night ratios calculated to determine local contributions to PMx mass concentrations. With regard to the emission measurements, results of mass and elemental

  14. Simultaneous measurement of X-ray specular reflection and off-specular diffuse scattering from liquid surfaces using a two-dimensional pixel array detector: the liquid-interface reflectometer of BL37XU at SPring-8.

    PubMed

    Yano, Yohko F; Uruga, Tomoya; Tanida, Hajime; Toyokawa, Hidenori; Terada, Yasuko; Yamada, Hironari

    2010-07-01

    An X-ray reflectometer for simultaneous measurement of specular and off-specular reflection of liquid surfaces is described. The reflectometer, equipped with a two-dimensional single X-ray photon-counting pixel array detector obtained the full range of X-ray specular and off-specular reflections in an extremely short time (1 s). Both the specular and off-specular reflection of water exhibited good agreement with the predicted capillary-wave theory within the appropriate instrumental resolution. The approach is also demonstrated on an aqueous solution of 1-dodecyl-3-methylimidazolium chloride. The monolayer in which the dodecyl chain faces upwards and the Cl(-) anion locates next to the imidazolium ring formed on the water surface was found to be laterally homogeneous. The use of a pixel array detector will be particularly powerful for in situ measurements to investigate both out-of-plane and in-plane structures simultaneously, not only for liquid surfaces but also for other thin films.

  15. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  16. X-Ray Vision

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Elsner, R. F.; Engelhaupt, D.; Kolodziejczak, J. J.; ODell, S. L.; Speegle, C. O.; Weisskopf, M. C.

    2004-01-01

    We are fabricating optics for the hard-x-ray region using electroless nickel replication. The attraction of this process, which has been widely used elsewhere, is that the resulting full shell optics are inherently stable and thus can have very good angular resolution. The challenge with this process is to develop lightweight optics (nickel has a relatively high density of 8.9 g/cu cm), and to keep down the costs of mandrel fabrication. We accomplished the former through the development of high-strength nickel alloys that permit very thin shells without fabrication- and handling-induced deformations. For the latter, we have utilized inexpensive grinding and diamond turning to figure the mandrels and then purpose-built polishing machines to finish the surface. In-house plating tanks and a simple water-bath separation system complete the process. To date we have built shells ranging in size from 5 cm diameter to 50 cm, and with thickness down to 100 micron. For our HERO balloon program, we are fabricating over 200 iridium-coated shells, 250 microns thick, for hard-x-ray imaging up to 75 keV. Early test results on these have indicated half-power-diameters of 15 arcsec. The status of these and other hard-x-ray optics will be reviewed.

  17. X-Ray Vision

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Elsner, R. F.; Engelhaupt, D.; Kolodziejczak, J. J.; ODell, S. L.; Speegle, C. O.; Weisskopf, M. C.

    2004-01-01

    We are fabricating optics for the hard-x-ray region using electroless nickel replication. The attraction of this process, which has been widely used elsewhere, is that the resulting full shell optics are inherently stable and thus can have very good angular resolution. The challenge with this process is to develop lightweight optics (nickel has a relatively high density of 8.9 g/cu cm), and to keep down the costs of mandrel fabrication. We accomplished the former through the development of high-strength nickel alloys that permit very thin shells without fabrication- and handling-induced deformations. For the latter, we have utilized inexpensive grinding and diamond turning to figure the mandrels and then purpose-built polishing machines to finish the surface. In-house plating tanks and a simple water-bath separation system complete the process. To date we have built shells ranging in size from 5 cm diameter to 50 cm, and with thickness down to 100 micron. For our HERO balloon program, we are fabricating over 200 iridium-coated shells, 250 microns thick, for hard-x-ray imaging up to 75 keV. Early test results on these have indicated half-power-diameters of 15 arcsec. The status of these and other hard-x-ray optics will be reviewed.

  18. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  19. X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    Dr. S. N. Zhang has lead a seven member group (Dr. Yuxin Feng, Mr. XuejunSun, Mr. Yongzhong Chen, Mr. Jun Lin, Mr. Yangsen Yao, and Ms. Xiaoling Zhang). This group has carried out the following activities: continued data analysis from space astrophysical missions CGRO, RXTE, ASCA and Chandra. Significant scientific results have been produced as results of their work. They discovered the three-layered accretion disk structure around black holes in X-ray binaries; their paper on this discovery is to appear in the prestigious Science magazine. They have also developed a new method for energy spectral analysis of black hole X-ray binaries; four papers on this topics were presented at the most recent Atlanta AAS meeting. They have also carried Monte-Carlo simulations of X-ray detectors, in support to the hardware development efforts at Marshall Space Flight Center (MSFC). These computation-intensive simulations have been carried out entirely on the computers at UAH. They have also carried out extensive simulations for astrophysical applications, taking advantage of the Monte-Carlo simulation codes developed previously at MSFC and further improved at UAH for detector simulations. One refereed paper and one contribution to conference proceedings have been resulted from this effort.

  20. Study of multilayer structures as soft x-ray mirrors

    NASA Astrophysics Data System (ADS)

    Kim, D.; Lee, H. W.; Cha, D.; Lee, J. J.; Je, J. H.

    1995-05-01

    Molybdenum-silicon multilayer as soft x-ray mirrors have been fabricated using a magnetron sputtering system. Their structures have been characterized by x-ray diffraction (XRD) and computer simulation. Reflectivities at normal incidence have been measured by using monochromatized synchrotron radiation in the 18-24 nm region. A normal incidence reflectivity as high as 40% at 20.8 nm was achieved. Multilayer structural parameters optimized for various soft x-ray laser wavelengths are also given.