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1

The High-Throughput X-Ray Spectroscopy Mission. Report of the Instrument Working Group  

Microsoft Academic Search

The High-Throughput X-Ray Spectroscopy Mission represents a cornerstone of the European Space Agency's science programme. A range of possible instruments for this mission are reviewed and a trade-off analysis is performed among them in order to establish which are most likely to satisfy the mission's scientific objectives. As a result of this analysis, a model payload is proposed.

U. Briel; A. C. Brinkman; J. M. Ellwood; G. W. Fraser; P. A. J. de Korte; J. Lemmon; D. H. Lumb; G. Manzo; A. Peacock; E. Pfeffermann; R. Rocchia; N. J. Westergaard

1987-01-01

2

The new ambient-pressure X-ray photoelectron spectroscopy instrument at MAX-lab.  

PubMed

The new instrument for near-ambient-pressure X-ray photoelectron spectroscopy which has been installed at the MAX II ring of the Swedish synchrotron radiation facility MAX IV Laboratory in Lund is presented. The new instrument, which is based on a SPECS PHOIBOS 150 NAP analyser, is the first to feature the use of retractable and exchangeable high-pressure cells. This implies that clean vacuum conditions are retained in the instrument's analysis chamber and that it is possible to swiftly change between near-ambient and ultrahigh-vacuum conditions. In this way the instrument implements a direct link between ultrahigh-vacuum and in situ studies, and the entire pressure range from ultrahigh-vacuum to near-ambient conditions is available to the user. Measurements at pressures up to 10(-5)?mbar are carried out in the ultrahigh-vacuum analysis chamber, while measurements at higher pressures are performed in the high-pressure cell. The installation of a mass spectrometer on the exhaust line of the reaction cell offers the users the additional dimension of simultaneous reaction data monitoring. Moreover, the chosen design approach allows the use of dedicated cells for different sample environments, rendering the Swedish ambient-pressure X-ray photoelectron spectroscopy instrument a highly versatile and flexible tool. PMID:22898948

Schnadt, Joachim; Knudsen, Jan; Andersen, Jesper N; Siegbahn, Hans; Pietzsch, Annette; Hennies, Franz; Johansson, Niclas; Mårtensson, Nils; Ohrwall, Gunnar; Bahr, Stephan; Mähl, Sven; Schaff, Oliver

2012-08-07

3

Photon excitation for satellite free x-ray spectroscopy: Instrumentation challenges  

SciTech Connect

First systematic study of satellites in x-ray emission spectra was performed by Deslattes using quasi-monochromatic photon excitation from a group of L{alpha} x-ray sources lying close to the K edge of Cl. He observed significant alterations in the Cl K{beta} spectrum of KCl depending on the character of the excitation radiation and identified the initial state of these satellites as a double vacancy state. Recently, the valence electronic structure of the chlorofluoromethanes were analyzed by chlorine K x-ray emission under satellite-free conditions. These studies were based on the use of synchrotron radiation to eliminate the multivacancy effects that are inherent in conventional x-ray spectroscopy. In this report, satellite free x-ray emission spectra from chlorofluoromethanes will be presented to demonstrate that the simplified spectra can be obtained using selective photon excitation. Results from various research groups world wide, utilizing the tunable photon excitation form synchrotron sources to eliminate the obscuring features in x-ray emission spectra of rare-gas solids (RGS) and metals will be discussed. Also, the technical challenges in utilizing the small phase-space attributes of high brightness from third generation SR sources producing x-ray and vacuum ultra-violet wavelengths to study weak features like satellites in x-ray emission spectra will be presented.

Perera, R.C.C.

1991-10-01

4

New Concepts for X-Ray, Soft X-Ray, and EUV Optical Instrumentation Including Applications in Spectroscopy, Plasma Diagnostics, and Biomedical Microscopy: A Status Report  

Microsoft Academic Search

In this article, we review current progress in the development of several techniques for extreme ultraviolet, soft x-ray, and x-ray optical instrumentation. Applications of these concepts include diagnostics of hot plasmas, spectroscopic studies of the interaction of multicharged ion beams with matter (atoms, ions, molecules, microstructures, surfaces, solids), and biomedical x-ray microscopy. Novel applications of components include the use of

V. L. Kantsyrev; R. Bruch; R. Phaneuf; N. G. Publicover

1997-01-01

5

X-ray evolving universe spectroscopy mission (XEUS): requirements of the x-ray focal plane instruments  

Microsoft Academic Search

The requirement set for the focal plane instruments on XEUS area addressed. The rationale for the selection of three focal plane instruments, a wide field imager with modest spectral resolution and tow narrow field imagers with high spectral resolution, is given. The principles and designs of all three instrument are shortly explained and their expected performances given. The cooling of

Piet A. de Korte; Markos Bavdaz; Lionel Duband; Andrew D. Holland; Anthony J. Peacock; Lothar Strueder

1999-01-01

6

X-ray Absorption Spectroscopy  

SciTech Connect

This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

Yano, Junko; Yachandra, Vittal K.

2009-07-09

7

X-ray spectroscopy of low-mass X-ray binaries  

Microsoft Academic Search

I present high-resolution X-ray grating spectroscopy of neutron stars in low-mass X-ray binaries (LMXBs) using instruments onboard the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission (XMM-Newton). The first part of this thesis concentrates on results from the subset of LMXBs with orbital periods less than an hour, known as ultracompact binaries. Previous low- resolution X-ray spectra of four systems

Adrienne Marie Juett

2004-01-01

8

New Concepts for X-Ray, Soft X-Ray, and EUV Optical Instrumentation Including Applications in Spectroscopy, Plasma Diagnostics, and Biomedical Microscopy: A Status Report.  

PubMed

In this article, we review current progress in the development of several techniques for extreme ultraviolet, soft x-ray, and x-ray optical instrumentation. Applications of these concepts include diagnostics of hot plasmas, spectroscopic studies of the interaction of multicharged ion beams with matter (atoms, ions, molecules, microstructures, surfaces, solids), and biomedical x-ray microscopy. Novel applications of components include the use of glass capillary converters (GCCs) and multilayer mirrors (MLMs) or crystals. GCC devices provide guiding, focusing, and polarization analysis of short wavelength radiation over a wide bandwidth. The MLM or crystal optical elements can be used for dispersing, focusing, and polarization-sensitive studies of radiation within a narrow bandwidth. In this report we focus on the development and testing of optical diagnostic devices for the short wavelength spectral region 0.1 nm < ? < 100 nm. PMID:21307546

Kantsyrev, V L; Bruch, R; Phaneuf, R; Publicover, N G

1997-01-01

9

Large Area X-Ray Spectroscopy Mission.  

National Technical Information Service (NTIS)

The Large Area X-ray Spectroscopy (LAXS) mission concept study continues to evolve strongly following the merging of the LAXS mission with the Next Generation X-ray Observatory (NGXO, PI: Nick White) into the re-named High Throughput X-ray Spectroscopy (H...

H. Tananbaum

1997-01-01

10

X-Ray Photoelectron Spectroscopy  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. Glasses of the systems Ge-Se-X (X = Ga, Sn, Bi, Sb), Ge-S-Y (Y = Ag, Ga, Sn, Bi) and Se-S have been examined using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), density and differential scanning calorimetry (DSC). Two of the compositions, GeSe_2 and (GeSe_2)_{92}Ga _8, have also been examined by extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES). The emphasis of the XPS measurements was on the changes in the binding energies with composition of the core peaks of the glasses, and on the plasmon energy losses from the L_3M_ {4,5}M_{4,5} Auger lines of Se and Ge. It was found that there were small shifts in the binding energies of the core peaks on substitution but the plasmon energy changed markedly with composition. For the XRD measurements, the focus was on two features: (a) to ensure that the samples prepared were truly amorphous and (b) to confirm the presence of the first sharp diffraction peak (FSDP) on the interference functions. The density measurements showed that the addition of the third element (X or Y) to the binary resulted in an increase in the relative density except for one system, Ge-Se-Sn, which showed the opposite behaviour. The DSC measurements showed that the addition of the third element to the binary resulted in a decrease in the glass transition temperatures. The EXAFS and XANES measurements of GeSe _2 and (GeSe_2)_ {92}Ga_8 glasses showed that there was very little change in the local order around the Ge atom in GeSe_2 glass with increase in temperature and that the local order around the Ge atom changes on alloying GeSe_2 with Ga. Correlations between parameters and measured properties of the ternary alloys have been investigated. It has been found that the parameter < m>, the average coordination number, correlates well with certain structural properties but badly with others. Suggestions are made for an alternative to .

Saffarini, Ghassan

11

Resonant x-ray emission spectroscopy of liquid water: novel instrumentation, high resolution, and the"map" approach  

SciTech Connect

Techniques to study the electronic structure of liquids are rare. Most recently, resonant x-ray emission spectroscopy (XES) has been shown to be an extremely versatile spectroscopy to study both occupied and unoccupied electronic states for liquids in thermodynamic equilibrium. However, XES requires high-brilliance soft x-ray synchrotron radiation and poses significant technical challenges to maintain a liquid sample in an ultra-high vacuum environment. Our group has therefore developed and constructed a novel experimental setup for the study of liquids, with the long-term goal of investigating the electronic structure of biological systems in aqueous environments. We have developed a flow-through liquid cell in which the liquid is separated from vacuum by a thin Si3N4 or SiC window and which allows a precise control of temperature. This approach has significant advantages compared to static liquids cells used in the past. Furthermore, we have designed a dedicated high-transmission, high-resolution soft x-ray spectrometer. The high transmission makes it possible to measure complete resonant XES"maps" in less than an hour, giving unprecedented detailed insight into the electronic structure of the investigated sample. Using this new equipment we have investigated the electronic structure of liquid water. Furthermore, our XES spectra and maps give information about ultra-fast dissociation on the timescale of the O 1s core hole lifetime, which is strongly affected by the initial state hydrogen bonding configuration.

Weinhardt, L.; Fuchs, O.; Blum, M.; Bär, M.; Weigand, M.; Denlinger, J.D.; Zubavichus, Y.; Zharnikov, M.; Grunze, M.; Heske, C.; Umbach, E.

2008-06-17

12

X-ray Fluorescence Spectroscopy of Novel Materials  

Microsoft Academic Search

This review focuses on the capabilities and potential of soft x-ray fluorescence spectroscopy for the study of the electronic\\u000a structure and chemical bonding of novel materials. The basic principle of x-ray fluorescence measurements using synchrotron\\u000a radiation and the corresponding instrumentation issues are outlined. Particular attention is given to x-ray spectroscopic\\u000a studies of the electronic structure and characterization of nanostructures, thin

E. Z. Kurmaev

2005-01-01

13

X-ray Spectroscopy of Cooling Cluster  

SciTech Connect

We review the X-ray spectra of the cores of clusters of galaxies. Recent high resolution X-ray spectroscopic observations have demonstrated a severe deficit of emission at the lowest X-ray temperatures as compared to that expected from simple radiative cooling models. The same observations have provided compelling evidence that the gas in the cores is cooling below half the maximum temperature. We review these results, discuss physical models of cooling clusters, and describe the X-ray instrumentation and analysis techniques used to make these observations. We discuss several viable mechanisms designed to cancel or distort the expected process of X-ray cluster cooling.

Peterson, J.R.; /SLAC; Fabian, A.C.; /Cambridge U., Inst. of Astron.

2006-01-17

14

The X-Ray Multi-Mirror Mission: A New Capability for High Throughput X-Ray Spectroscopy  

Microsoft Academic Search

The X-Ray Multi-Mirror Mission (XMM) is an observatory class facility under development by the European Space Agency for launch in January 2000. XMM will provide unprecedented capabilities for both high and moderate resolution X-ray spectroscopy of cosmic X-ray sources. The observatory incorporates three co-aligned, densely-nested, high throughput, grazing incidence X-ray telescopes. There are three scientific instruments on board: (1) the

S. M. Kahn

1999-01-01

15

X-ray photon spectroscopy calculations  

SciTech Connect

X-ray photons - as many other particles - interact with matter producing secondary radiation that carries useful information about the atoms comprising the target. The availability of intense sources of highly monochromatic X-rays and the great improvement in detector technology intensified research in X-ray spectrometry in the last twenty years. New techniques allowed the attenuation coefficients and the physics of the atom to be better known: Extended X-ray Absorption Fine Structure (EXAFS), X-ray Absorption Near Edge Structure (XANES), and Inelastic X-ray Scattering Spectroscopy (IXSS). Old techniques, like X-ray Fluorescence (XRF), gained in precision thus extending the horizon of applicability to new elements and energy ranges, and consequently Energy Dispersive X-ray Fluorescence (EDXRF) and Synchrotron Radiation X-ray Fluorescence (SRXRF) were evolved. Particle induced X-ray emission spectroscopy also benefited from this improvement. The field of application of X-ray spectrometry has grown from atomic, to nuclear, to plasma physics, to astrophysics. In this work the authors summarize the knowledge recently gained about how the intensity due to multiple scattering perturbs the first-order terms of the three processes of main interest in X-ray spectrometry between 1 keV and 100 keV: the photoelectric, the Rayleigh and the Compton effects. They show that the contribution of a few orders of scattering, calculated in the frame of transport theory, allows the construction of a theoretical X-ray spectrum that matches well experimental data from targets of homogeneous composition and infinite thickness. 99 refs., 15 figs.

Fernandez, J.E.; Molinari, V.G. [Univ. of Bologna (Italy)

1991-12-31

16

European XFEL: Soft X-Ray instrumentation  

SciTech Connect

The currently constructed European X-Ray Free Electron Laser (XFEL) will generate new knowledge in almost all the technical and scientific disciplines that are shaping our daily life-including nanotechnology, medicine, pharmaceutics, chemistry, materials science, power engineering and electronics. On 8 January 2009, civil engineering work (tunnels, shafts, halls) has been started at all three construction sites. In this presentation status and parameters of the European XFEL facility and instrumentation as well as planned research applications particularly in the range of soft X-rays are reviewed.

Molodtsov, S. L., E-mail: serguei.molodtsov@xfel.eu [European XFEL GmbH (Germany)

2011-12-15

17

X-Ray Interferometry and Space Instrumentation  

SciTech Connect

In x-ray astronomy the technique of interferometry has the potential to provide ultra-high angular resolution imaging of at least 100 {mu}as and possibly 1 {mu}as, which would be good enough to image the event horizon of a black hole. At the University of Leicester we are proposing a practical x-ray interferometer to give 100 {mu}as angular resolution, which can be built using current x-ray optics capabilities and existing detector technology. The complete instrument would be about 20 m long and about 2 m in diameter. The key to the design is the use of a slatted mirror to combine the two beams. Simulations and recent measurements of an optical demonstrator have been encouraging.

Butcher, Gillian [Space Research Centre, Department of Physics and Astronomy, University of Leicester (United Kingdom)

2005-10-17

18

X-ray microprobe for micro x-ray fluorescence and absorption spectroscopies at GSECARS  

Microsoft Academic Search

The hard x-ray microprobe for x-ray fluorescence and absorption spectroscopy at GeoSoilEnviroCARS is presented. Using focused synchrotron radiation from an undulator beamline at the Advanced Photon Source at Argonne National Lab, the x-ray microprobe provides bright, monochromatic x-rays with typical spot sizes down to 1x1 mum for x-ray fluorescence and absorption spectroscopies. Quantitative x-ray fluorescence (XRF) analysis gives precise elemental

M. Newville; S. Sutton; M. Rivers

2002-01-01

19

X-Ray Spectroscopy with PIN diodes  

SciTech Connect

A PIN diode and a low noise preamplifier are included in a nuclear spectroscopy chain for X-ray measurements. This is a laboratory session designed to review the main concepts needed to set up the detector-preamplifier array and to make measurements of X-ray energy spectra with a room temperature PIN diode. The results obtained are compared with those obtained from radioactive sources with a high resolution cooled Si-Li detector.

Ramirez-Jimenez, F. J. [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, La Marquesa, Ocoyoacac, 57150 (Mexico)

2006-09-25

20

X-ray spectroscopy of NGC 5548  

Microsoft Academic Search

We analyze the high-resolution X-ray spectrum of the Seyfert 1 galaxy NGC\\u000a5548, for the full 0.1-10 keV band, using improved calibration results of the\\u000aChandra-LETGS instrument. The warm absorber consists of at least three\\u000aionization components, namely one with a low, medium and high ionization\\u000aparameter. The X-ray absorbing material, from an outflowing wind, covers the\\u000afull range of

J. S. Kaastra; K. C. Steenbrugge; A. J. J. Raassen; Meer van der R. L. J; A. C. Brinkman; D. A. Liedahl; E. Behar; A. de Rosa

2002-01-01

21

Diamond detectors for x-ray spectroscopy  

NASA Astrophysics Data System (ADS)

Polycrystalline diamond detector prototypes suitable for x-ray spectroscopy were realized and tested. Thick diamond specimens, mechanically polished to reduce the surface roughness, were selected for prototypes development. Noble metal contacts were deposited on both faces, whereas multistrip structures were defined by photolithography on the growth face only with the aim of reducing the coupling capacitances and to allow characterization tests either in planar or sandwich configuration. Leakage currents as low as 20 pA at 500 V were measured on a 270?m thick device. The x-ray sensitivity was tested monitoring the photocurrent as a function of the applied voltage under continuous 8.05 keV Cu K? irradiation. Studies in pulsed mode were also performed by using a commercial miniature x-ray source. Pulse height distributions were carried out with a system composed of a charge-sensitive preamplifier and a digital pulse processor multi-channel analyzer. Analysis was carried out around Ta L? and Cu K? characteristic lines. Realized prototypes were able to resolve such two characteristic lines only 90 eV apart. Energy resolutions better than 3% have been evaluated for one of the prototype at 8.14 keV. Such features address very good energy resolving capabilities and the suitability of polished polycrystalline diamond in x-ray spectroscopy.

Allegrini, P.; Girolami, M.; Calvani, P.; Conte, G.; Salvatori, S.; Spiriti, E.; Ralchenko, V.

2008-08-01

22

High Resolution Astrophysical X-ray Spectroscopy  

NASA Astrophysics Data System (ADS)

High resolution X-ray spectroscopy of cosmic plasmas has undergone a revolution, since the launch of the Chandra and XMM-Newton observatories two years ago. Both carry diffraction grating spectrometers, which are now providing a stream of very high quality, completely novel data, on every kind of astrophysical object. I will discuss some of the more spectacular spectroscopic surprises, and show how both familiar and new diagnostics provide detailed information of a new order on the radiation sources.

Paerels, Frits

2002-10-01

23

Tomographic x-ray absorption spectroscopy.  

SciTech Connect

Hard x-ray absorption spectroscopy is combined with scanning microtomography to reconstruct full near edge spectra of an elemental species at each point on an arbitrary virtual section through a sample. These spectra reveal the local concentration of different chemical compounds of the absorbing element inside the sample and give insight into the oxidation state and the local projected free density of states. The method is implemented by combining a quick scanning monochromator and data acquisition system with a scanning microprobe setup based on refractive x-ray lenses. The full XANES spectra reconstructed at each point of the tomographic slice allow one to detect slight variations in concentration of the chemical compounds, such as Cu and Cu(I){sub 2}O.

Schroer, C. G.; Kuhlmann, M.; Gunzler, T. F.; Lengeler, B.; Richwin, M.; Griesebock, B.; Lutzenkirchen-Hecht, D.; Frahm, R.; Ziegler, E.; Mashayekhi, A.; Haeffner, D. R.; Grunwaldt, J. -D.; Baiker, A.; Experimental Facilities Division (APS); Aachen Univ.; HASYLAB at DESY; Bergische Univ. Wuppertal; ESRF; Inst. for Chemical and Bioengineering

2004-01-01

24

X-ray spectroscopy of low-mass X-ray binaries  

NASA Astrophysics Data System (ADS)

I present high-resolution X-ray grating spectroscopy of neutron stars in low-mass X-ray binaries (LMXBs) using instruments onboard the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission (XMM-Newton). The first part of this thesis concentrates on results from the subset of LMXBs with orbital periods less than an hour, known as ultracompact binaries. Previous low- resolution X-ray spectra of four systems (4U 0614+091, 2S 0918-549, 4U 1543-624, and 4U 1850-087) all contain a broad residual near 0.7 keV which had been attributed to unresolved line emission. I show that this residual is due to an incorrect model of the intervening photoelectric absorption and can be accounted for by allowing a non-standard Ne/O abundance ratio in the intervening material. I propose that there is neon-rich material local to each binary and that the mass donor is a low-mass, neon-rich degenerate dwarf in an ultracompact binary. Follow-up spectroscopy of 2S 0918-549 and 4U 1543-624 with the High Energy Transmission Grating Spectrometer (HETGS) onboard Chandra and the Reflection Grating Spectrometer onboard XMM confirms the excess neutral neon absorption. Interestingly, the Ne/O ratio of 4U 1543-624 varies by a factor of three between the Chandra and XMM observations, supporting the suggestion that some of the absorption originates local to the binaries. I also present X-ray spectroscopy of another ultracompact binary, the accretion-powered millisecond pulsar XTE J0929-314. No emission or absorption features are found in the high-resolution spectrum of this source, and the neutral absorption edge depths are consistent with the estimated interstellar absorption. The second part of this thesis uses LMXBs as probes of the interstellar medium (ISM). High-resolution X-ray studies of ISM absorption features can provide measurements of the relative abundances and ionization fractions of all the elements from carbon through iron. X-ray studies also probe the ISM on larger scales than is possible in the optical and ultraviolet wavebands. I present high-resolution spectroscopy of the oxygen K-shell ISM absorption edge in seven X- ray binaries using Chandra. The best-fit model consists of two absorption edges and five Gaussian absorption lines and can be explained by the recent theoretical calculations of K-shell absorption by neutral and ionized atomic oxygen. Significant oxygen features from dust or molecular components, suggested in previous studies, are not required by the Chandra spectra. These measurements also probe large-scale properties of the ISM, placing a limit on the velocity dispersion of the neutral lines of less than 200 km s-1 and constraining the interstellar ratio of O II/O I to approximately 0.1 and the ratio of O III/O I to less than 0.1. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Juett, Adrienne Marie

2004-10-01

25

Development and applications of grazing exit micro X-ray fluorescence instrument using a polycapillary X-ray lens  

Microsoft Academic Search

A polycapillary X-ray lens is an effective optics to obtain a ?m-size X-ray beam for micro-X-ray fluorescence spectrometry (?-XRF). We developed a ?-XRF instrument using a polycapillary X-ray lens, which also enabled us to perform Grazing Exit ?-XRF (GE-?-XRF). The evaluated diameter of the primary X-ray beam was 48 ?m at the focal distance of the X-ray lens. Use of

T. Emoto; Y. Sato; Y. Konishi; X. Ding; K. Tsuji

2004-01-01

26

Requirements for future solar-physics missions with X ray instrumentation  

NASA Astrophysics Data System (ADS)

Several overall requirements for solar x-ray missions are stated and an outline of the underlying coronal physics is presented. The available techniques for x-ray imaging of the Sun are discussed and compared with reference to previous and ongoing missions. Solar x-ray spectroscopy is assessed in the same manner. Possible choices for future instruments in these two areas are discussed. X-rays are taken to lie broadly in the photon energy range 0.1 to 100 keV. Solar studies at these energies will be mainly concerned with high temperature coronal plasma and nonthermal radiation from particle beams produced in flares.

Culhane, J. L.

1993-06-01

27

High resolution instruments based on X-ray multilayer gratings  

Microsoft Academic Search

New possibilities in the development of spectral instruments with high resolution and efficiency are opened up by the X-ray multilayer gratings. The main advantage of such gratings in the range of the soft X-ray radiation is their greater operating angles and high reflection coefficients. The high spectral resolution is provided by the large number of operating grooves with the same

V. I. Erofeev; N. V. Kovalenko; E. P. Kruglyakov; O. K. Myskinand; N. I. Chkhalo

1999-01-01

28

X-ray photon spectroscopy calculations  

Microsoft Academic Search

X-ray photons - as many other particles - interact with matter producing secondary radiation that carries useful information about the atoms comprising the target. The availability of intense sources of highly monochromatic X-rays and the great improvement in detector technology intensified research in X-ray spectrometry in the last twenty years. New techniques allowed the attenuation coefficients and the physics of

J. E. Fernandez; V. G. Molinari

1991-01-01

29

X-Ray Spectroscopy of Gold Nanoparticles  

Microsoft Academic Search

Inner shell transitions, such as 1s-2p, in heavy elements can absorb or produce hard X-rays, and hence are widely used in nanoparticles. Bio-medical research for cancer treatment has been using heavy element nanoparticles, embeded in malignant tumor, for efficient absorption of irradiated X-rays and leading emission of hard X-rays and energetic electrons to kill the surrounding cells. Ejection of a

Sultana N. Nahar; M. Montenegro; A. K. Pradhan; R. Pitzer

2009-01-01

30

X-ray Background Signals in Total Reflection X-ray Fluorescence Spectroscopy  

Microsoft Academic Search

Total Reflection X-ray Fluorescence Spectroscopy (TXRF) is widely used for wafer surface analysis. An important figure of merit is its sensitivity, defined as 3*signal\\/sqrt(background). Since the signals can be small compared to the background, it is essential to fully understand the background components when considering possible improvements. This talk describes recent experimental and theoretical progress in understanding the X-ray background

N. Takaura; A. Waldhauer; S. Brennan; P. Pianetta; S. S. Laderman; A. Fischer-Colbrie

1996-01-01

31

An X-ray diffraction and X-ray absorption spectroscopy joint study of neuroglobin  

Microsoft Academic Search

Neuroglobin (Ngb) is a member of the globin family expressed in the vertebrate brain, involved in neuroprotection. A combined approach of X-ray diffraction (XRD) on single crystal and X-ray absorption spectroscopy (XAS) in solution, allows to determine the oxidation state and the structure of the Fe–heme both in the bis-histidine and the CO-bound (NgbCO) states. The overall data demonstrate that

Alessandro Arcovito; Tommaso Moschetti; Paola D’Angelo; Giordano Mancini; Beatrice Vallone; Maurizio Brunori; Stefano Della Longa

2008-01-01

32

X-ray absorption spectroscopy in coordination chemistry  

Microsoft Academic Search

X-ray absorption spectroscopy (XAS) is one of the premier tools for investigating the local structural environment of metal ions. XAS can be divided into X-ray absorption near edge structure (XANES), which provides information primarily about geometry and oxidation state, and extended X-ray absorption fine structure (EXAFS) which provides information about metal site ligation. One of the key attractions of XAS

James E. Penner-Hahn

1999-01-01

33

Calorimeters for very high resolution x-ray spectroscopy  

Microsoft Academic Search

In our work following the invention of the x-ray calorimeter, we improved the resolution to 7.3 eV, at which point our emphasis changed from demonstration to application. Our recent calorimeter development effort has proceeded along two tracks, one for soft (<1 keV) x-rays and the other for broad band (0.5-12 keV) x-ray spectroscopy. We have achieved 10-15 eV resolution with

C. K. Stahle; R. L. Kelley; S. H. Moseley; D. B. Mott; A. E. Szymkowiak; F. M. Finkbeiner; K. C. Gendreau; F. S. Porter; D. McCammon; M. Juda; J. Zhang

1997-01-01

34

X-ray-induced photo-chemistry and X-ray absorption spectroscopy of biological samples.  

PubMed

As synchrotron light sources and optics deliver greater photon flux on samples, X-ray-induced photo-chemistry is increasingly encountered in X-ray absorption spectroscopy (XAS) experiments. The resulting problems are particularly pronounced for biological XAS experiments. This is because biological samples are very often quite dilute and therefore require signal averaging to achieve adequate signal-to-noise ratios, with correspondingly greater exposures to the X-ray beam. This paper reviews the origins of photo-reduction and photo-oxidation, the impact that they can have on active site structure, and the methods that can be used to provide relief from X-ray-induced photo-chemical artifacts. PMID:23093745

George, Graham N; Pickering, Ingrid J; Pushie, M Jake; Nienaber, Kurt; Hackett, Mark J; Ascone, Isabella; Hedman, Britt; Hodgson, Keith O; Aitken, Jade B; Levina, Aviva; Glover, Christopher; Lay, Peter A

2012-10-18

35

X-ray-induced photo-chemistry and X-ray absorption spectroscopy of biological samples  

PubMed Central

As synchrotron light sources and optics deliver greater photon flux on samples, X-ray-induced photo-chemistry is increasingly encountered in X-ray absorption spectroscopy (XAS) experiments. The resulting problems are particularly pronounced for biological XAS experiments. This is because biological samples are very often quite dilute and therefore require signal averaging to achieve adequate signal-to-noise ratios, with correspondingly greater exposures to the X-ray beam. This paper reviews the origins of photo-reduction and photo-oxidation, the impact that they can have on active site structure, and the methods that can be used to provide relief from X-ray-induced photo-chemical artifacts.

George, Graham N.; Pickering, Ingrid J.; Pushie, M. Jake; Nienaber, Kurt; Hackett, Mark J.; Ascone, Isabella; Hedman, Britt; Hodgson, Keith O.; Aitken, Jade B.; Levina, Aviva; Glover, Christopher; Lay, Peter A.

2012-01-01

36

The Scientific Impact of High Resolution X-ray Spectroscopy  

NASA Astrophysics Data System (ADS)

A new era of high resolution X-ray spectroscopy began with the launches of Chandra and XMM-Newton in 1999. In the same way Chandra represents a factor of 100 improvement in spatial resolution compared to ASCA, the High and Low Energy Transmission Grating Spectrometers (HETGS/LETGS) aboard Chandra and the Reflection Grating Spectrometer (RGS) aboard XMM-Netwon represent factors of 5-400 improvement in X-ray spectral resolution. This overview talk for a special session on high resolution X-ray spectroscopy will discuss the dramatic science impact made possible by this advancement in capability. We will briefly discuss the technical capabilities of these instruments, and specifically address how for certain science goals, gratings observations actually are "less expensive" than comparable signal-to-noise CCD observations. More importantly, we will discuss those kinds of measurements that are only achievable with high resolution spectroscopy. These include line-of-sight velocities (as small as 30 km s^{-1}!), velocity widths, detailed plasma diagnostics via line strengths and ratios, and detection of weak absorption lines. These have allowed sensitive studies of astrophysical plasmas in a wide variety of contexts: magnetically confined winds in stars, accretion flows and outflows in binaries and active galactic nuclei, and even studies of the inter-stellar and inter-galactic media. Doppler velocities have been used to make three-dimensional images of supernova remnants. More detailed discussions of the impact of gratings studies in these and other science areas will be the focus of the remainder of this special session.

Canizares, C. R.; Huenemoerder, D.; Marshall, H.; Nowak, M.; Schulz, N. S.

2006-09-01

37

Crystal optics for hard-X-ray spectroscopy of highly charged ions  

NASA Astrophysics Data System (ADS)

A twin crystal-spectrometer assembly, operated in the focusing compensated asymmetric Laue geometry has been developed for accurate spectroscopy of fast highly charged heavy ions in the hard-X-ray region. Coupled to the focusing crystal optics is a specially developed two-dimensional position-sensitive X-ray detector which is necessary for retaining spectral resolution also for fast moving sources. We summarize the crystal optics and demonstrate the usefulness of the instrument for spectroscopy of both stationary and fast moving X-ray sources. Results are reported from several tests employing a 169Yb gamma-ray source and the Lyman radiation of one-electron Pb 81+ ions traveling at a velocity corresponding to ? ? v/ c ? 0.59. The features of the instrument presented may be useful in many applications where it appears difficult to make the leap from conventional X-ray energy measurements to wavelength-dispersive spectroscopy based on crystal optics.

Beyer, H. F.; Attia, D.; Banas, D.; Le Bigot, E.-O.; Bosch, F.; Dousse, J.-Cl.; Förster, E.; Gumberidze, A.; Hagmann, S.; Heß, S.; Hoszowska, J.; Indelicato, P.; Jagodzinski, P.; Kozhuharov, Chr.; Krings, Th.; Liesen, D.; Ma, X.; Manil, B.; Mohos, I.; Pajek, M.; Proti?, D.; Reuschl, R.; Rzadkiewicz, J.; Simionovici, A.; Spillmann, U.; Stachura, Z.; Stöhlker, Th.; Trassinelli, M.; Trotsenko, S.; Warczak, A.; Wehrhan, O.; Ziegler, E.

2009-08-01

38

The advantages of soft X-rays and cryogenic spectrometers for measuring chemical speciation by X-ray spectroscopy  

Microsoft Academic Search

We have built a 36-pixel high-resolution superconducting tunnel junction (STJ) soft X-ray spectrometer for chemical analysis of dilute metals by fluorescence-detected X-ray absorption spectroscopy (XAS) at the Advanced Light Source synchrotron. Soft X-ray absorption edges are preferred over traditional hard X-ray spectroscopy at the K-edges, since they have narrower natural linewidths and exhibit stronger chemical shifts. STJ detectors are preferred

Owen B. Drury; Stephan Friedrich; Simon J. George; Stephen P. Cramer

2006-01-01

39

A high-resolution large-acceptance analyzer for X-ray fluorescence and Raman spectroscopy  

SciTech Connect

A newly designed multi-crystal X-ray spectrometer and its applications in the fields of X-ray fluorescence and X-ray Raman spectroscopy are described. The instrument is based on 8 spherically curved Si crystals, each with a 3.5 inch diameter form bent to a radius of 86 cm. The crystals are individually aligned in the Rowland geometry capturing a total solid angle of 0.07 sr. The array is arranged in a way that energy scans can be performed by moving the whole instrument, rather than scanning each crystal by itself. At angles close to back scattering the energy resolution is between 0.3 and 1 eV depending on the beam dimensions at the sample. The instrument is mainly designed for X-ray absorption and fluorescence spectroscopy of transition metals in dilute systems such as metalloproteins. First results of the Mn K{beta} (3p -> 1s) emission in photosystem II are shown. An independent application of the instrument is the technique of X-ray Raman spectroscopy which can address problems similar to those in traditional soft X-ray absorption spectroscopies, and initial results are presented.

Bergmann, Uwe; Cramer, Stephen P.

2001-08-02

40

Spectroscopy and X-Ray Astronomy  

NASA Astrophysics Data System (ADS)

The new x-ray astronomical observatories have sufficient spectroscopic capability to allow the determination of plasma conditions in the form of velocities, temperatures, densities, and turbulence parameters at levels that were previously unattainable. The utilization of these diagnostics are possible only if the atomic and plasma physics are well-enough understood to match the observational sensitivity.

Holt, Stephen S.

2000-10-01

41

Sliced multilayer grating x-ray spectroscopy  

Microsoft Academic Search

Low energy monochromatic x rays can be ]used to detect the attenuation differences between fibrous, fat, and cancerous tissues in mammography, evaluation of computer processor chips, as well as quality control for micro components. At 17 keV, carcinomas, fibrous and fatty tissues attenuate incident radiation to different degrees which permits non invasive detection of cancerous tissue. A sliced transmission multilayer

Michele M. Wilson; Muamer Zukic; Jongmin Kim; Douglas G. Torr; Alphonsus J. Fennelly; Edward L. Fry

1994-01-01

42

Method for X-ray fluorescence spectroscopy  

Microsoft Academic Search

A method and apparatus are described for performing X-ray fluorescence analysis where the physical relationship between the source\\/detector and the object being examined is not controlled. This technique and apparatus is particularly advantageous in performing an in situ analysis of the concentration of one or more elements present in a matrix of a material such as rock. In accordance with

W. C. Boyce; T. E. Hall; L. C. Howard; W. M. Lechelt; W. D. Wittekind

1985-01-01

43

Hard x-ray photoelectron spectroscopy and x-ray standing waves  

Microsoft Academic Search

Using the brilliant undulator radiation available from the third generation synchrotron sources, hard x-ray photoelectron spectroscopy (HAXPES) has become an emerging field in the recent years. With the excitation energy used in HAXPES one can benefits from the large mean free path of fast electrons (˜ 5 nm for electrons of 6 keV kinetic energy) in probing the bulk electronic

Tien-Lin Lee

2006-01-01

44

Developments in extreme ultraviolet and x ray instrumentation  

NASA Astrophysics Data System (ADS)

An overview of the symposium to review the future photon detector needs for ESA's long term science program 'Horizon 2000' and beyond is presented. Once future requirements for detector instrumentation are determined it will be possible to focus the agency's technological research program on the key areas requiring further development and support. In the region covering extreme ultraviolet (EUV) and x-ray wavelengths, a number of papers demonstrated the current limitations of various detector systems and highlighted possible future developments and trends. A resume of the principle issues, raised at the symposium specifically for EUV and x-ray photon detectors, is provided.

Peacock, A.; Bleeker, J. A. M.

1992-12-01

45

X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy studies of Cu-doped ZnO films  

Microsoft Academic Search

Cu-doped ZnO films have been prepared using direct current co-reactive magnetron sputtering technique at different oxygen partial pressures. The microstructure and the chemical state of oxygen, copper and zinc in ZnO films was investigated by X-ray diffraction spectroscopy (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The results indicate that ZnO films with moderate Cu doping can obtain wurtzite structure with

H. Xue; Y. Chen; X. L. Xu; G. H. Zhang; H. Zhang; S. Y. Ma

2009-01-01

46

The soft x-ray materials research (SXR) instrument at the Linac Coherent Light Source  

NASA Astrophysics Data System (ADS)

The soft x-ray materials science research (SXR) instrument completed commissioning in June 2010 and began experimental user operations shortly afterwards. This instrument delivers intense, ultra-short soft x-ray pulses from the Linac Coherent Light Source, the free-electron laser at the SLAC National Accelerator Laboratory. These are fully coherent and can contain up to 10^13 photons per pulse (or about 3 mJ per pulse) with bunch lengths from 300 femtoseconds down to sub-10 femtoseconds. The instrument includes a monochromator whose energy range spans energies from 480 eV - 2000 eV and a Kirkpatrick-Baez mirror system to create a focal spot of a few microns in diameter. The SXR instrument has a diverse set of end stations available to conduct a large variety of experimental techniques such as coherent imaging, resonant x-ray diffraction, photoelectron spectroscopy, and x-ray emission and/or absorption. First studies include fields spanning liquid femtosecond chemistry and time-resolved resonant inelastic x-ray scattering to ordering in solids and ultrafast magnetization. An overview of the instrument and its capabilities will be given.

Turner, Joshua J.; Krupin, Oleg; Schlotter, William

2011-03-01

47

Soft-x-ray spectroscopy study of nanoscale materials  

SciTech Connect

The ability to control the particle size and morphology of nanoparticles is of crucial importance nowadays both from a fundamental and industrial point of view considering the tremendous amount of high-tech applications. Controlling the crystallographic structure and the arrangement of atoms along the surface of nanostructured material will determine most of its physical properties. In general, electronic structure ultimately determines the properties of matter. Soft X-ray spectroscopy has some basic features that are important to consider. X-ray is originating from an electronic transition between a localized core state and a valence state. As a core state is involved, elemental selectivity is obtained because the core levels of different elements are well separated in energy, meaning that the involvement of the inner level makes this probe localized to one specific atomic site around which the electronic structure is reflected as a partial density-of-states contribution. The participation of valence electrons gives the method chemical state sensitivity and further, the dipole nature of the transitions gives particular symmetry information. The new generation synchrotron radiation sources producing intensive tunable monochromatized soft X-ray beams have opened up new possibilities for soft X-ray spectroscopy. The introduction of selectively excited soft X-ray emission has opened a new field of study by disclosing many new possibilities of soft X-ray resonant inelastic scattering. In this paper, some recent findings regarding soft X-ray absorption and emission studies of various nanostructured systems are presented.

Guo, J.-H.

2005-07-30

48

X-ray diffraction assisted spectroscopy of Rydberg states  

SciTech Connect

X-ray diffraction combined with conventional spectroscopy could provide a powerful means to characterize electronically excited atoms and molecules. We demonstrate theoretically how x-ray diffraction from laser excited atoms can be used to determine electronic structure, including angular momentum composition, principal quantum numbers, and channel populations. A theoretical formalism appropriate for highly excited atoms, and easily extended to molecules, is presented together with numerical results for Xe and H atoms.

Kirrander, Adam [ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)

2012-10-21

49

New focusing multilayer structures for X-ray plasma spectroscopy  

SciTech Connect

New focusing short-period multilayer structures are developed which opens up wide possibilities for X-ray and VUV spectroscopy. Multilayer structures are deposited on a flat surface of a mica crystal which is then bent to a small-radius cylinder. The use of this structure in a von Hamos spectrometer for X-ray laser plasma diagnostics is demonstrated. (interaction of laser radiation with matter. laser plasma)

Bibishkin, M S; Luchin, V I; Salashchenko, N N; Chernov, V V; Chkhalo, N I [Institute for Physics of Microstructures, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation); Kazakov, E D; Shevelko, A P [P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2008-02-28

50

Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides  

SciTech Connect

The subjects of discussion included: VUV photoelectron spectroscopy, X-ray photoelectron spectroscopy, Synchrotron-radiation-based photoelectron spectroscopy, Soft x-ray absorption spectroscopy, Soft x-ray emission spectroscopy, Inverse photoelectron spectroscopy, Bremstrahlung Isochromat Spectroscopy, Low energy IPES, Resonant inverse photoelectron spectroscopy.

Tobin, J G

2011-03-17

51

EUV spectroscopy of high-redshift x-ray objects  

NASA Astrophysics Data System (ADS)

As astronomical observations are pushed to cosmological distances (z>3) the spectral energy distributions of X-ray objects, AGN for example, will be redshifted into the EUV waveband. Consequently, a wealth of critical spectral diagnostics, provided by, for example, the Fe L-shell complex and the O VII/VIII lines, will be lost to future planned X-ray missions (e.g., IXO, Gen-X) if operated at traditional X-ray energies. This opens up a critical gap in performance located at short EUV wavelengths, where critical X-ray spectral transitions occur in high-z objects. However, normal-incidence multilayer-grating technology, which performs best precisely at such wavelengths, together with advanced nanolaminate replication techniques have been developed and are now mature to the point where advanced EUV instrument designs with performance complementary to IXO and Gen-X are practical. Such EUV instruments could be flown either independently or as secondary instruments on these X-ray missions. We present here a critical examination of the limits placed on extragalactic EUV measurements by ISM absorption, the range where high-z measurements are practical, and the requirements this imposes on next-generation instrument designs. We conclude with a discussion of a breakthrough technology, nanolaminate replication, which enables such instruments.

Kowalski, M. P.; Wolff, M. T.; Wood, K. S.; Barbee, T. W., Jr.; Barstow, M. A.

2010-07-01

52

Femtosecond x-ray absorption spectroscopy with hard x-ray free electron laser  

NASA Astrophysics Data System (ADS)

We have developed a method of dispersive x-ray absorption spectroscopy with a hard x-ray free electron laser (XFEL), generated by a self-amplified spontaneous emission (SASE) mechanism. A transmission grating was utilized for splitting SASE-XFEL light, which has a relatively large bandwidth (?E/E ~ 5 × 10-3), into several branches. Two primary split beams were introduced into a dispersive spectrometer for measuring signal and reference spectra simultaneously. After normalization, we obtained a Zn K-edge absorption spectrum with a photon-energy range of 210 eV, which is in excellent agreement with that measured by a conventional wavelength-scanning method. From the analysis of the difference spectra, the noise ratio was evaluated to be ~3 × 10-3, which is sufficiently small to trace minute changes in transient spectra induced by an ultrafast optical laser. This scheme enables us to perform single-shot, high-accuracy x-ray absorption spectroscopy with femtosecond time resolution.

Katayama, Tetsuo; Inubushi, Yuichi; Obara, Yuki; Sato, Takahiro; Togashi, Tadashi; Tono, Kensuke; Hatsui, Takaki; Kameshima, Takashi; Bhattacharya, Atanu; Ogi, Yoshihiro; Kurahashi, Naoya; Misawa, Kazuhiko; Suzuki, Toshinori; Yabashi, Makina

2013-09-01

53

X-ray induced damage in DNA monitored by X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

In this work, the chemical changes in calf thymus DNA samples were analyzed by X-ray photoelectron spectroscopy (XPS). The DNA samples were irradiated for over 5 h and spectra were taken repeatedly every 30 min. In this approach the X-ray beam both damages and probes the samples. In most cases, XPS spectra have complex shapes due to contributions of C, N, and O atoms bonded at several different sites. We show that from a comparative analysis of the modification in XPS line shapes of the C 1s, O 1s, N 1s, and P 2p peaks, one can gain insight into a number of reaction pathways leading to radiation damage to DNA.

Ptasi?ska, Sylwia; Stypczy?ska, Agnieszka; Nixon, Tony; Mason, Nigel J.; Klyachko, Dimitri V.; Sanche, Léon

2008-08-01

54

X-ray induced damage in DNA monitored by X-ray photoelectron spectroscopy  

SciTech Connect

In this work, the chemical changes in calf thymus DNA samples were analyzed by X-ray photoelectron spectroscopy (XPS). The DNA samples were irradiated for over 5 h and spectra were taken repeatedly every 30 min. In this approach the X-ray beam both damages and probes the samples. In most cases, XPS spectra have complex shapes due to contributions of C, N, and O atoms bonded at several different sites. We show that from a comparative analysis of the modification in XPS line shapes of the C 1s, O 1s, N 1s, and P 2p peaks, one can gain insight into a number of reaction pathways leading to radiation damage to DNA.

Ptasinska, Sylwia; Stypczynska, Agnieszka; Nixon, Tony; Mason, Nigel J. [Department of Physics and Astronomy, Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); Klyachko, Dimitri V.; Sanche, Leon [Groupe en Sciences des Radiations, Departement de Medecine Nucleaire et de Radiobiology, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, J1H 5N4 Quebec (Canada)

2008-08-14

55

Indirectly illuminated X-ray area detector for X-ray photon correlation spectroscopy.  

PubMed

An indirectly illuminated X-ray area detector is employed for X-ray photon correlation spectroscopy (XPCS). The detector consists of a phosphor screen, an image intensifier (microchannel plate), a coupling lens and either a CCD or CMOS image sensor. By changing the gain of the image intensifier, both photon-counting and integrating measurements can be performed. Speckle patterns with a high signal-to-noise ratio can be observed in a single shot in the integrating mode, while XPCS measurement can be performed with much fewer photons in the photon-counting mode. By switching the image sensor, various combinations of frame rate, dynamic range and active area can be obtained. By virtue of these characteristics, this detector can be used for XPCS measurements of various types of samples that show slow or fast dynamics, a high or low scattering intensity, and a wide or narrow range of scattering angles. PMID:20975218

Shinohara, Yuya; Imai, Ryo; Kishimoto, Hiroyuki; Yagi, Naoto; Amemiya, Yoshiyuki

2010-10-01

56

X-ray Spectroscopy with the SODART/XSPECT Telescope  

NASA Astrophysics Data System (ADS)

The SOviet-DAnish Röntgen Telescope (SODART) on board the Spectrum Röntgen Gamma (SRG) satellite will be equipped with three different instruments devoted to X-ray spectroscopy. Each of the two thin foil telescopes has an 8 m focal length, a 60 cm diameter, a 1 deg field-of-view (FOV), a <2 arcmin half-power width and ca. 1700 and 1200 cm2 collecting area at 2 and 8 keV, respectively. Broad band (0.25 - 25 keV) imaging spectroscopy over the full FOV will be obtained from low- and high-energy imaging proportional counters with energy resolution as good as 28 and 14 percent (FWHM) at 1.5 and 6 keV, respectively, and with an efficiency >70 percent (2 - 25 keV). The central 18 arcmin of the FOV of one telescope will be viewed by an array of 19 cooled silicon detectors with energy resolution of 140 and 160 eV at 2 and 6 keV, respectively, and efficiency >85 percent (2 - 20 keV). Each detector element will subtend a 3.4 arcmin FOV. A full FOV objective crystal spectrometer in front of the other telescope will obtain high resolution imaged spectra of point and extended sources with an energy resolution of 2, 1 and 2 eV at 0.7, 2.5 and 6.7 keV, respectively.

Schnopper, Herbert W.

57

The high-throughput X-ray spectroscopy mission E6889478 MN513835  

Microsoft Academic Search

Instrumentation to satisfy ESA's X-ray spectroscopy mission requirements of spatial resolution within 30 arc sec HEW; effective area: 10,000 sq cm at 2 keV; 5000 sq cm at 8 keV; broadband 0.1 to 10 keV spectroscopy with a resolving power of between 5 and 60; medium-resolution spectroscopy between 0.1 to 3 keV with a resolving power of over 250; and

U. Briel; A. C. Brinkman; J. M. Ellwood; G. W. Fraser; P. A. J. Dekorte; J. Lemmon; D. H. Lumb; G. Manzo; A. Peacock; E. Pfeffermann

1987-01-01

58

Hard x-ray spectroscopy for proton flare prediction  

NASA Astrophysics Data System (ADS)

High energy interplanetary proton events can jeopardize vital military and civilian spacecraft by disrupting logical circuits and by actually damaging spacecraft electronic components. Studies of solar hard x-rays indicate that high-energy proton events observed near Earth are highly associated with an uncommon type of solar flare exhibiting temporal progressively hardening hard x-ray spectra. A hard x-ray spectrometer is being developed by the Czech Astronomical Institute to provide a test bed for evaluating this phenomenon as a possible proton-storm prediction method. The instrument is designed to measure hard x-ray spectra in a high fluence, high-energy particle background environment such as that found at geosynchronous altitude. This experiment has been selected for space flight by the DoD Space Test Program and will fly aboard the Department of Energy satellite, Multi-spectral thermal Imager, scheduled for a three year mission, beginning in late 1999. The timing of this mission, fortuitously, coincides with the experiment are: 1) to evaluate the efficacy of this type of solar instrument in predicting interplanetary proton storms; 2) to study the high-energy physics of solar flares in concert with the premier flight of the NOAA soft x-ray imaging telescope, SXI, on the GOES 12 weather satellite and other solar mission. If the first goal is demonstrated by this mission, continuous monitoring of the Sun for proton events could become operational from geo-synchronous orbit during solar cycle 24.

Garcia, Howard A.; Farnik, Frantisek; Kiplinger, Alan L.

1998-11-01

59

Time-resolved x-ray absorption spectroscopy apparatus using laser plasma as an x-ray source  

Microsoft Academic Search

A time-resolved x-ray absorption spectroscopy apparatus on a laboratory scale is being prepared which utilizes a laser plasma as an x-ray source. One of the major aims imposed on this apparatus is to observe x-ray absorption or reflection spectra of various materials in an energy region from 100 eV up to 3 keV. For this purpose, two sets of optical

Osamu Yoda; Atsumi Miyashita; Kouichi Murakami; Sadao Aoki; Naohiro Yamaguchi

1991-01-01

60

High Resolution X-Ray Imaging and Spectroscopy of AGN and SS 433 with the Chandra X-Ray Observatory  

Microsoft Academic Search

We present some early results on AGN and jets with the Chandra X-ray Observatory, highlighting high resolution spectroscopy using the High Energy Transmission Grating Spectrometer (HETGS). The quasar PKS 0637--752 was found to have a very bright X-ray jet whose shape is remarkably similar to that of the radio jet on a size scale of 100 kpc but the X-ray

H. L. Marshall

2000-01-01

61

X-ray photoelectron spectroscopy and diffraction in the hard X-ray regime: Fundamental considerations and future possibilities  

Microsoft Academic Search

The prospects for extending X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD) measurements into the hard X-ray regime of 5–15keV excitation energies are discussed from a fundamental point of view, in some cases using prior results obtained in the 1–2keV range as starting points of discussion, together with theoretical estimates of behavior at higher energies. Subjects treated are: the

Charles S. Fadley

2005-01-01

62

X-ray photoelectron spectroscopy and diffraction in the hard X-ray regime: Fundamental considerations and future possibilities  

Microsoft Academic Search

The prospects for extending X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD) measurements into the hard X-ray regime of 5-15 keV excitation energies are discussed from a fundamental point of view, in some cases using prior results obtained in the 1-2 keV range as starting points of discussion, together with theoretical estimates of behavior at higher energies. Subjects treated

Charles S. Fadleya

63

X-ray photoelectron spectroscopy and diffraction in the hard X-ray regime: Fundamental considerations and future possibilities  

Microsoft Academic Search

The prospects for extending X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD) measurements into the hard X-ray regime of 5 15 keV excitation energies are discussed from a fundamental point of view, in some cases using prior results obtained in the 1 2 keV range as starting points of discussion, together with theoretical estimates of behavior at higher energies.

Charles S. Fadley

2005-01-01

64

Bulk-sensitive XAS characterization of light elements: from X-ray Raman scattering to X-ray Raman spectroscopy  

Microsoft Academic Search

X-Ray absorption spectroscopy (XAS) is a powerful tool for element-specific characterization of local structure and chemistry. Although application of XAS in the hard X-ray region is now routine, the soft X-ray region (containing light-element K-edges) presents a number of experimental problems. Most of the difficulties, including surface sensitivity, restricted sample environments, and radiation damage, stem from the submicron path lengths

Uwe Bergmann; Pieter Glatzel; Stephen P. Cramer

2002-01-01

65

X-ray standing waves and hard X-ray photoelectron spectroscopy at the insertion device beamline ID32  

Microsoft Academic Search

Investigations on the geometrical structure, chemical composition and electronic properties of surfaces and interfaces are performed on beamline ID32 at the ESRF. It is a high resolution beamline covering the photon energy range 1.4–30keV optimized for X-ray standing wave, surface X-ray diffraction, and hard X-ray photoelectron spectroscopy experiments. Fresnel zone plates and compound refractive lens systems are used to focus

Jörg Zegenhagen; Blanka Detlefs; Tien-Lin Lee; Sebastian Thiess; Helena Isern; Lucien Petit; Lionel André; Jérôme Roy; Yanyu Mi; Isabelle Joumard

2010-01-01

66

Single atom identification by energy dispersive x-ray spectroscopy  

SciTech Connect

Using aberration-corrected scanning transmission electron microscope and energy dispersive x-ray spectroscopy, single, isolated impurity atoms of silicon and platinum in monolayer and multilayer graphene are identified. Simultaneously acquired electron energy loss spectra confirm the elemental identification. Contamination difficulties are overcome by employing near-UHV sample conditions. Signal intensities agree within a factor of two with standardless estimates.

Lovejoy, T. C.; Dellby, N.; Krivanek, O. L. [Nion, 1102 8th St., Kirkland, Washington 98033 (United States); Ramasse, Q. M. [SuperSTEM Laboratory, STFC Daresbury, Keckwick Lane, Daresbury WA4 4AD (United Kingdom); Falke, M.; Kaeppel, A.; Terborg, R. [Bruker Nano GmbH, Schwarzschildstr. 12, 12489 Berlin (Germany); Zan, R. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

2012-04-09

67

Soft x-ray fluorescence spectroscopy using tunable synchrotron radiation  

Microsoft Academic Search

The introduction of high brightness synchrotron radiation sources has opened up new possibilities for using soft x-ray fluorescence spectroscopy in the study of electronic structure. Selective excitation allows site specific emission to be studied, satellite structure due to multiple excitation to be separated, resonant phenomena to be investigated, etc. In particular, it has been found that inelastic scattering becomes dominating

Joseph E. Nordgren; Nial Wassdahl

1995-01-01

68

X-ray Photoelectron Spectroscopy of Explosive Solids.  

National Technical Information Service (NTIS)

A wide-ranging program to apply the new technique of X-ray photoelectron spectroscopy to the study of explosive solids is described, along with major findings to date. Significant general contributions are summarized: (a) The potential importance of a new...

J. Sharma T. Gora S. Bulusu D. A. Wiegand

1974-01-01

69

Proton induced quasi-monochromatic x-ray beams for soft x-ray spectroscopy studies and selective x-ray fluorescence analysis.  

PubMed

We present the analytical features and performance of an x-ray spectroscopy end station of moderate energy resolution operating with proton-induced quasi-monochromatic x-ray beams. The apparatus was designed, installed and operated at the 5.5 MV Tandem VdG Accelerator Laboratory of the Institute of Nuclear Physics, N.C.S.R. "Demokritos," Athens. The setup includes a two-level ultrahigh vacuum chamber that hosts in the lower level up to six primary targets in a rotatable holder; there, the irradiation of pure element materials-used as primary targets-with few-MeV high current (~?A) proton beams produces intense quasi-monochromatic x-ray beams of selectable energy. In the chamber's upper level, a six-position rotatable sample holder hosts the targets considered for x-ray spectroscopy studies. The proton-induced x-ray beam, after proper collimation, is guided to the sample position whereas various filters can be also inserted along the beam's path to eliminate the backscattered protons or/and to absorb selectively components of the x-ray beam. The apparatus incorporates an ultrathin window Si(Li) spectrometer (FWHM 136 eV at 5.89 keV) coupled with low-noise electronics capable of efficiently detecting photons down to carbon K?. Exemplary soft x-ray spectroscopy studies and results of selective x-ray fluorescence analysis are presented. PMID:23277967

Sokaras, D; Zarkadas, Ch; Fliegauf, R; Beckhoff, B; Karydas, A G

2012-12-01

70

Proton induced quasi-monochromatic x-ray beams for soft x-ray spectroscopy studies and selective x-ray fluorescence analysis  

SciTech Connect

We present the analytical features and performance of an x-ray spectroscopy end station of moderate energy resolution operating with proton-induced quasi-monochromatic x-ray beams. The apparatus was designed, installed and operated at the 5.5 MV Tandem VdG Accelerator Laboratory of the Institute of Nuclear Physics, N.C.S.R. 'Demokritos,' Athens. The setup includes a two-level ultrahigh vacuum chamber that hosts in the lower level up to six primary targets in a rotatable holder; there, the irradiation of pure element materials-used as primary targets-with few-MeV high current ({approx}{mu}A) proton beams produces intense quasi-monochromatic x-ray beams of selectable energy. In the chamber's upper level, a six-position rotatable sample holder hosts the targets considered for x-ray spectroscopy studies. The proton-induced x-ray beam, after proper collimation, is guided to the sample position whereas various filters can be also inserted along the beam's path to eliminate the backscattered protons or/and to absorb selectively components of the x-ray beam. The apparatus incorporates an ultrathin window Si(Li) spectrometer (FWHM 136 eV at 5.89 keV) coupled with low-noise electronics capable of efficiently detecting photons down to carbon K{alpha}. Exemplary soft x-ray spectroscopy studies and results of selective x-ray fluorescence analysis are presented.

Sokaras, D. [Institute of Nuclear Physics, N.C.S.R. Demokritos, Aghia Paraskevi, 15310 Athens (Greece); Zarkadas, Ch. [PANalytical B.V., 7600 AA Almelo (Netherlands); Fliegauf, R.; Beckhoff, B. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Karydas, A. G. [Institute of Nuclear Physics, N.C.S.R. Demokritos, Aghia Paraskevi, 15310 Athens (Greece); Nuclear Spectrometry and Applications Laboratory, IAEA Laboratories, A-2444 Seibersdorf (Austria)

2012-12-15

71

Rolf Mewe: a career devoted to X-ray spectroscopy  

NASA Astrophysics Data System (ADS)

An overview of the life and work of Rolf Mewe (1935-2004) as an X-ray spectroscopist is given. He was one of the pioneers in the field of X-ray spectroscopy. His work illustrates nicely how this field developed from the early days up to the present high-resolution era. His plasma emission codes, developed by him and collaborators over several decades, is one of the most widely used. His thorough knowledge of the field, as well as his ability and enthousiasm to cooperate with many colleagues, made his career a succes. He will be missed by all of us for his work and personality.

Kaastra, Jelle S.; Mewe, Rolf

2005-06-01

72

AlGaAs diodes for X-ray spectroscopy  

NASA Astrophysics Data System (ADS)

Al0.8Ga0.2As p+ p- n+ diodes with low reverse leakage currents (<10 nA) were evaluated as room temperature (23 °C), soft X-ray photon-counting detectors. X-ray spectra from a 55Fe radioactive source show these diodes can be used for spectroscopy with promising energy resolution of 1.47 keV FWHM at 5.9 keV. At elevated reverse bias levels (>20 V), we observed avalanche multiplication which, while improving the signal-to-noise ratio, degraded the spectroscopic performance.

Lees, J. E.; Bassford, D. J.; Ng, J. S.; Tan, C. H.; David, J. P. R.

2008-09-01

73

Instrumentation for Microfabrication with Deep X-ray Lithography  

Microsoft Academic Search

Deep X-ray lithography for microfabrication is performed at least at ten synchrotron radiation centers worldwide. The characteristic energies of these sources range from 1.4 keV up to 8 keV, covering mask making capabilities, deep X-ray lithography up to ultra deep x-ray lithography of several millimeters resist thickness. Limitations in deep X-ray lithography arise from hard X-rays in the SR-spectrum leading

F. J. Pantenburg

2007-01-01

74

Biological X-ray absorption spectroscopy and metalloproteomics.  

PubMed

In the past seven years the size of the known protein sequence universe has been rapidly expanding. At present, more then five million entries are included in the UniProtKB/TrEMBL protein database. In this context, a retrospective evaluation of recent X-ray absorption studies is undertaken to assess its potential role in metalloproteomics. Metalloproteomics is the structural and functional characterization of metal-binding proteins. This is a new area of active research which has particular relevance to biology and for which X-ray absorption spectroscopy is ideally suited. In the last three years, biological X-ray absorption spectroscopy (BioXAS) has been included among the techniques used in post-genomics initiatives for metalloprotein characterization. The emphasis of this review is on the progress in BioXAS that has emerged from recent meetings in 2007-2008. Developments required to enable BioXAS studies to better contribute to metalloproteomics throughput are also discussed. Overall, this paper suggests that X-ray absorption spectroscopy could have a higher impact on metalloproteomics, contributing significantly to the understanding of metal site structures and of reaction mechanisms for metalloproteins. PMID:19395808

Ascone, Isabella; Strange, Richard

2009-04-01

75

Simultaneous surface plasmon resonance and x-ray absorption spectroscopy  

SciTech Connect

We present an experimental setup for the simultaneous measurement of surface plasmon resonance (SPR) and x-ray absorption spectroscopy (XAS) on metallic thin films at a synchrotron beamline. The system allows measuring in situ and in real time the effect of x-ray irradiation on the SPR curves to explore the interaction of x-rays with matter. It is also possible to record XAS spectra while exciting SPR in order to study changes in the films induced by the excitation of surface plasmons. Combined experiments recording simultaneously SPR and XAS curves while scanning different parameters can be also carried out. The relative variations in the SPR and XAS spectra that can be detected with this setup range from 10{sup -3} to 10{sup -5}, depending on the particular experiment.

Serrano, A. [Instituto de Ceramica y Vidrio (ICV-CSIC), Cantoblanco, 28049 Madrid (Spain); Departamento de Fisica de Materiales, Universidad Complutense de Madrid, 28040 Madrid (Spain); Rodriguez de la Fuente, O. [Departamento de Fisica de Materiales, Universidad Complutense de Madrid, 28040 Madrid (Spain); Collado, V.; Rubio-Zuazo, J.; Castro, G. R. [SpLine, Spanish CRG Beamline at the ESRF, F-38043 Grenoble, Cedex 09, France and Instituto de Ciencia de Materiales de Madrid, (ICMM-CSIC), Cantoblanco, 28049 Madrid (Spain); Monton, C. [Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093 (United States); Garcia, M. A. [Instituto de Ceramica y Vidrio (ICV-CSIC), Cantoblanco, 28049 Madrid (Spain); IMDEA Nanociencia, Cantoblanco, 28049 Madrid (Spain)

2012-08-15

76

Simultaneous surface plasmon resonance and x-ray absorption spectroscopy.  

PubMed

We present an experimental setup for the simultaneous measurement of surface plasmon resonance (SPR) and x-ray absorption spectroscopy (XAS) on metallic thin films at a synchrotron beamline. The system allows measuring in situ and in real time the effect of x-ray irradiation on the SPR curves to explore the interaction of x-rays with matter. It is also possible to record XAS spectra while exciting SPR in order to study changes in the films induced by the excitation of surface plasmons. Combined experiments recording simultaneously SPR and XAS curves while scanning different parameters can be also carried out. The relative variations in the SPR and XAS spectra that can be detected with this setup range from 10(-3) to 10(-5), depending on the particular experiment. PMID:22938268

Serrano, A; Rodríguez de la Fuente, O; Collado, V; Rubio-Zuazo, J; Monton, C; Castro, G R; García, M A

2012-08-01

77

Instrumentation of the hard x-ray telescope mission  

NASA Astrophysics Data System (ADS)

The hard x-ray telescope (HXT) was selected for study as a possible new intermediate size mission for the early 21st century. Its principal attributes are: (1) multiwavelength observing with a system of focusing telescopes that collectively observe from the UV to over 1 MeV, (2) much higher sensitivity and much better angular resolution in the 10 - 100 keV band, and (3) higher sensitivity for detecting gamma ray lines of known energy in the 100 keV to 1 MeV band. The institutions collaborating in the study are: Smithsonian Astrophysical Observatory, Marshall Space Flight Center, Naval Research Laboratory, Goddard Space Flight Center, Argonne National Laboratory, Danish Space Research Institute, Osservatorio Astronomica di Brera (Merate), and Centre d'Etudes Spatiale des Rayonnements (Toulouse). This paper emphasizes the instrumentation development aspects of the concept study which is also of interest to other possible missions observing hard x rays. The instrumentation includes several grazing incidence double conical telescopes with multilayer coatings that focus up to 100 keV and a single Laue crystal telescope that functions to 1 MeV. The detectors which are relatively small thanks to focusing include CCDs, and germanium, and/or CdZnTe position sensitive arrays.

Gorenstein, Paul

1996-10-01

78

An upgraded x-ray spectroscopy diagnostic on MST.  

PubMed

An upgraded x-ray spectroscopy diagnostic is used to measure the distribution of fast electrons in MST and to determine Z(eff) and the particle diffusion coefficient D(r). A radial array of 12 CdZnTe hard-x-ray detectors measures 10-150 keV Bremsstrahlung from fast electrons, a signature of reduced stochasticity and improved confinement in the plasma. A new Si soft-x-ray detector measures 2-10 keV Bremsstrahlung from thermal and fast electrons. The shaped output pulses from both detector types are digitized and the resulting waveforms are fit with Gaussians to resolve pileup and provide good time and energy resolution. Lead apertures prevent detector saturation and provide a well-known etendue, while lead shielding prevents pickup from stray x-rays. New Be vacuum windows transmit >2?keV x-rays, and additional Al and Be filters are sometimes used to reduce low energy flux for better resolution at higher energies. Measured spectra are compared to those predicted by the Fokker-Planck code CQL3D to deduce Z(eff) and D(r). PMID:21034007

Clayton, D J; Almagri, A F; Burke, D R; Forest, C B; Goetz, J A; Kaufman, M C; O'Connell, R

2010-10-01

79

Calorimeters for very high resolution x-ray spectroscopy  

NASA Astrophysics Data System (ADS)

In our work following the invention of the x-ray calorimeter, we improved the resolution to 7.3 eV, at which point our emphasis changed from demonstration to application. Our recent calorimeter development effort has proceeded along two tracks, one for soft (<1 keV) x-rays and the other for broad band (0.5-12 keV) x-ray spectroscopy. We have achieved 10-15 eV resolution with 0.25 mm2 pixels with HgTe absorbers providing high quantum efficiency through 12 keV, and we have achieved 7-10 eV resolution with 1 mm2 pixels with HgTe absorbers providing high quantum efficiency through 1 keV. Our future calorimeter development will continue to be guided by the different demands of soft x-ray and hard x-ray band experiments. In the soft band, improvements to the existing technology should improve the uniformity of performance across an array and improve the spectral resolution, to perhaps as good as 2 eV. Major improvement in the hard band will require the development of alternative thermometers to replace the ion-implanted silicon thermistors now used. We will summarize the status of the technology and will report the results of our latest development efforts.

Stahle, C. K.; Kelley, R. L.; Moseley, S. H.; Mott, D. B.; Szymkowiak, A. E.; Finkbeiner, F. M.; Gendreau, K. C.; Porter, F. S.; McCammon, D.; Juda, M.; Zhang, J.

1997-01-01

80

Ambient-Pressure X-ray Photoelectron Spectroscopy  

SciTech Connect

This workshop focused on the application of ambient pressure X-ray photoelectron spectroscopy (APXPS) to environmental science and catalysis. Pioneering work on APXPS was done in the early 1970's by Hans and Kai Siegbahn et al., who demonstrated that XPS can operate at pressures of up to 1 Torr. A new type of APXPS instrument that utilizes a differentially-pumped electrostatic lens system at the ALS in 2001 increased the pressure limit to above 5 Torr, which opened the door to XPS experiments on water and aqueous solutions at temperatures above the melting point, in equilibrium with the vapor pressure of water. The impact of APXPS on fields such as environmental and atmospheric science as well as heterogeneous catalysis is already visible in numerous high impact publications. Today several other synchrotron facilities around the world have already implemented beam lines for APXPS or planning to do so in the near future. The goal of this workshop (organized by Miquel Salmeron (Molecular Foundry, LBNL), B. Simon Mun (Advanced Light Source, LBNL) and Hendrik Bluhm (Chemical Sciences Division, LBNL)) was to bring together researchers interested in the technique, review its current progress, discuss scientific opportunities and desirable technical improvements as well as consider the consequences of the increased user demand on the existing beam lines and ways to expand the availability of time.

Bluhm, Hendrik; Bluhm, Hendrik; Mun, Bongjin Simon; Salmeron, Miquel

2008-04-01

81

X-ray and EUV diagnostics for the Nevada Terawatt Facility: plasma imaging, spectroscopy, and polarimetry  

Microsoft Academic Search

Summary form only given. A wide variety of advanced extreme ultraviolet (EUV) and X-ray diagnostics are being developed for the Nevada Terawatt Facility (NTF) at the University of Nevada, Reno. Time-resolved short-wavelength imaging, backlighting, imaging spectroscopy, and polarization spectroscopy will be employed to measure profiles of plasma temperature, density, flow, charge state, and magnetic field. The instruments are state-of-the-art applications

V. L. Kantsyrev; B. S. Bauer; R. C. Mancini; A. S. Shlyaptseva; D. A. Fdin; A. Golovkin; P. Hakel; I. Paraschiv; N. Ammons; S. Hansen

1999-01-01

82

Real-Time Data Processing for X-Ray Spectroscopy  

NASA Astrophysics Data System (ADS)

Over the last decade, the field of x-ray calorimeters has matured to the point where calorimeter instruments are becoming more common, requiring the development of turnkey systems that are easy to use for non-expert operators. In addition, the use of large arrays in spaceflight instruments requires a significant reduction in data density in order to remain compatible with highly restricted telemetry bandwidths. As calorimeter instruments mature and find wider use outside of the laboratory, the ability to perform signal analysis and data reduction on the raw data stream in real-time has gone from a convenience to a necessity. We will report on the adaptation of the Digital Signal Processor (DSP) based analysis electronics originally developed for the 32 channel Astro-E and Astro-E2 satellite missions to a full software version implemented with off-the-shelf hardware. This implementation requires a minimum of human intervention and is capable of real-time data analysis of x-ray events on many channels simultaneously, including triggering, optimal filtering and pulse height analysis. This suite has been successfully deployed in the XRS/EBIT and the EBIT/ECS experiments at Lawrence Livermore Laboratory and has been operational for over five years. We are currently scaling this system to much larger arrays as a test-bed for the XMS instrument on the International X-Ray Observatory (IXO) and for ground experiments such as the gamma-ray spectrometer at Los Alamos National Laboratory.

Adams, J. S.; Bandler, S. R.; Brown, L. E.; Boyce, K. R.; Chiao, M. P.; Doriese, W. B.; Eckart, M. E.; Hilton, G. C.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Rabin, M. W.; Smith, S. J.; Stewart, D. D.; Ullom, J. N.

2009-12-01

83

Effect of x-ray beamline optics on x-ray photon correlation spectroscopy experiments.  

SciTech Connect

We have evaluated the applicability of vertically-focusing kinoform lenses for tailoring the vertical coherence length of storage-ring undulator x-ray beams so that the entirety of the coherent flux can be used for small angle multi-speckle x-ray photon correlation spectroscopy (XPCS) experiments. We find that the focused beam produced by a kinoform lens preserves the coherence of the incident unfocused beam and that at an appropriate distance downstream of the focus, the diverging beam produces speckles nearly identical to those produced by an equivalently-sized unfocused beam. We have also investigated the effect of imperfect beamline optics on the observed coherence properties of the beam. Via phase contrast imaging and beam-divergence measurements, we find that a horizontally-deflecting mirror in our beamline precludes us from seeing the true radiation source point but instead acts as an apparent source of fixed size at the center of our insertion device straight section. Finally, we discuss how expected near-future optimization of these optics will greatly benefit XPCS measurements performed at beamline 8-ID-I at the Advanced Photon Source.

Sandy, A. R.; Evans-Lutterodt, K.; Fezzaa, K.; Kim, S.; Narayanan, S.; Sprung, M.; Stein, A.; X-Ray Science Division; BNL; Gwangiu Inst. of Science and Technology

2007-01-01

84

X-ray Spectroscopy of Neutron Star Low-Mass X-ray Binaries  

Microsoft Academic Search

In this thesis, I present work spanning a variety of topics relating to neutron star low-mass X-ray binaries (LMXBs) and utilize spectral information from X-ray observations to further our understanding of these sources. First, I give an overview of important X-ray astrophysics relevant to the work I present in subsequent chapters, as well as information about the X-ray observatories from

M. I. Krauss

2007-01-01

85

Ultrafast X-ray diffraction and X-ray absorption spectroscopy  

Microsoft Academic Search

Summary form only given. Recently developed ultrafast laser-driven X-ray sources enable the observation of atomic motions in crystals and in solutions on the timescale of chemical bond formation and breakage. Using such a laboratory-based X-ray source the propagation of coherent phonon wave packets through GaAs(111) crystals after photo excitation has been imaged by ultrafast X-ray difraction. While ultrafast x-ray diffraction

C. Rose-Petruck

2000-01-01

86

The Scientific Impact of High Resolution X-ray Spectroscopy  

Microsoft Academic Search

A new era of high resolution X-ray spectroscopy began with the launches of Chandra and XMM-Newton in 1999. In the same way Chandra represents a factor of 100 improvement in spatial resolution compared to ASCA, the High and Low Energy Transmission Grating Spectrometers (HETGS\\/LETGS) aboard Chandra and the Reflection Grating Spectrometer (RGS) aboard XMM-Netwon represent factors of 5-400 improvement in

C. R. Canizares; D. Huenemoerder; H. Marshall; M. Nowak; N. S. Schulz

2006-01-01

87

Instrumental aspects of x-ray microbeams in the range above 1 keV  

Microsoft Academic Search

X-ray microscopy has the capability of looking into normally opaque samples with high resolution. X rays are sensitive to elemental, structural, and chemical content and thus can provide microscopic maps of the composition and structure of a sample. X-ray microscopy has seen great growth in the last two decades in the number and types of operating instruments as well as

P. Dhez; P. Chevallier; T. B. Lucatorto; C. Tarrio

1999-01-01

88

Structure of reactively sputter deposited tin-nitride thin films: A combined X-ray photoelectron spectroscopy, in situ X-ray reflectivity and X-ray absorption spectroscopy study  

Microsoft Academic Search

Amorphous tin-nitride thin films were prepared by reactive sputter deposition on smooth float glass substrates in a vacuum chamber with an integrated small magnetron source. The films were investigated using in situ reflection mode X-ray absorption spectroscopy and ex situ X-ray photoelectron spectroscopy (XPS). Both the X-ray absorption near edge structure (XANES) and the extended X-ray absorption fine structure (EXAFS)

Dirk Lützenkirchen-Hecht; Ronald Frahm

2005-01-01

89

X-ray Intensity Fluctuation Spectroscopy Using Nanofocused Hard X-rays: Its Application to Study of Relaxor Ferroelectrics  

NASA Astrophysics Data System (ADS)

The use of a combination of coherent X-rays from a third-generation synchrotron light source and ultraprecise Kirkpatrick-Baez mirrors enables us to apply nanofocused hard X-rays in solid-state physics. We developed an apparatus for X-ray intensity fluctuation spectroscopy using the nanofocused hard X-rays and applied it to the study of relaxor ferroelectrics. We have successfully detected a large and slow intensity fluctuation of scattered X-rays above cubic-to-tetragonal phase transition temperature with a characteristic time scale on the order of 10 s. We speculated that the intensity fluctuation originates from domain number fluctuation, which is directly related to the dielectric response, particularly the frequency dispersion.

Kenji Ohwada,; Kazumichi Namikawa,; Susumu Shimomura,; Hironori Nakao,; Hidekazu Mimura,; Kazuto Yamauchi,; Mitsuyoshi Matsushita,; Jun'ichiro Mizuki,

2010-02-01

90

Energy dispersive X-ray spectroscopy with microcalorimeters  

NASA Astrophysics Data System (ADS)

Shrinking feature sizes in semiconductor device production as well as the use of new materials demand innovation in device technology and material analysis. X-ray spectrometers based on superconducting sensor technology are currently closing the gap between fast energy dispersive spectroscopy (EDS) and high-resolution wavelength dispersive spectroscopy (WDS). This work reports on the successful integration of iridium/gold transition edge sensors in the first industrially used microcalorimeter EDS. The POLARIS microcalorimeter system is installed at the failure analysis lab FA5 at Infineon Technologies AG in Neuperlach (Munich) and is used in routine analysis.

Hollerith, C.; Wernicke, D.; Bühler, M.; Feilitzsch, F. V.; Huber, M.; Höhne, J.; Hertrich, T.; Jochum, J.; Phelan, K.; Stark, M.; Simmnacher, B.; Weiland, W.; Westphal, W.

2004-03-01

91

High resolution near edge x-ray spectroscopy  

SciTech Connect

A technique to suppress the core-hole lifetime broadening in near- edge x-ray spectroscopy is presented. A simple theoretical explanation based on total energy conservation in the fluorescence process is given to explain the improved resolution. The experimental arrangement is shown together with an application to the L{sub III} edge of dysprosium. Furthermore, the application of high-resolution fluorescence spectroscopy in the study of magnetism is presented. The spin-resolved absorption spectra from MnF{sub 2} are shown as an example.

Haemaelaeinen, K.; Siddons, D.P.; Berman, L.E.; Kao, C.C.; Hastings, J.B.

1992-12-01

92

A versatile rapid-mixing and flow device for X-ray absorption spectroscopy.  

PubMed

A low-temperature rapid-mixing and flow system has been designed and implemented to monitor catalysis involving metal ions by X-ray absorption spectroscopy at the ID-18 beamline of the Advanced Photon Source, Argonne National Laboratory. The system will allow examination of biological metallo-intermediates at dilute metal ion concentrations by the detection of X-ray fluorescence. The instrument can be cooled to sub-zero temperatures, thus lengthening the life time of a reaction intermediate. A portable UV-visible spectrometer is integrated with the flow system to monitor the sample optically. The system can also be used as a continuous-flow device to minimize radiation-induced sample damage by reducing sample exposure to the X-ray beam. The integration of the stop-flow instrument with the synchrotron beamline and X-ray fluorescence detector systems makes it unique for time-resolved X-ray absorption studies of dilute biological reactions. The results of the initial testing of the system are presented. PMID:14960787

Zhang, Ke; Liu, Ruifeng; Irving, Tom; Auld, David S

2004-02-12

93

Soft X-Ray Spectroscopy of Semiconductor Nanocrystals  

NASA Astrophysics Data System (ADS)

Understanding the confinement and surface physics of doped and undoped nanocrystals is currently an important field of research. Quantum confinement effects as well as the impact of surface termination are critical to the design and future utilization of these novel materials in devices. We use soft x-ray probes such as x-ray absorption spectroscopy (XAS), photoelectron spectroscopy (PES), and soft x-ray fluorescence (SXF) experiments to determine the electronic structure of a variety of nanostructured materials. We report the changes in the band edge shifts and effect of surface termination of group IV nanocrystals as the particle shape is changed (i.e. from a sphere to a rod). Finally, we will show that synchrotron radiation techniques are an ideal tool to study the chemical environments of transition metal dopants in CdSe nanocrystals. This work was supported by the Division of Materials Sciences, Office of Basic Energy Science, and performed under the auspices of the U. S. DOE by LLNL under contract No. W-7405-ENG-48.

Meulenberg, Robert W.; van Buuren, Tony; Willey, Trevor M.; Terminello, Louis J.

2004-03-01

94

Operando X-ray absorption and infrared fuel cell spectroscopy  

SciTech Connect

A polymer electrolyte fuel cell enables operando X-ray absorption and infrared spectroscopy of the membrane electrode assembly catalytic layer with flowing fuel and air streams at controlled temperature. Time-dependent X-ray absorption near edge structure spectra of the Pt and Ni edge of Pt based catalysts of an air-breathing cathode show that catalyst restructuring, after a potential step, has time constants from minutes to hours. The infrared Stark tuning plots of CO adsorbed on Pt at 100, 200, 300 and 400 mV vs. hydrogen reference electrode were obtained. The Stark tuning plots of CO adsorbed at 400 mV exhibit a precipitous drop in frequency coincident with the adsorption potential. The turn-down potential decreases relative to the adsorption potential and is approximately constant after 300 mV. These Stark tuning characteristics are attributed to potential dependent adsorption site selection by CO and competitive adsorption processes.

Lewis, Emily A.; Kendrick, Ian; Jia, Qingying; Grice, Corey; Segre, Carlo U.; Smotkin, Eugene S. (NuVant); (IIT); (NEU)

2011-11-17

95

Simple X-ray cameras for beam-line instrumentation  

NASA Astrophysics Data System (ADS)

The design and performance characterization of simple X-ray cameras are shortly presented. These cameras are installed on each high-energy beam-lines of SOLEIL. Main topics, such as the choice of the scintillator, the effect of the thickness of the scintillator on the resolution, the relation between the X-ray flux and the signal, are addressed in this article.

Bordessoule, M.

2013-03-01

96

X-ray Imaging Spectroscopy for Planetary Science  

NASA Astrophysics Data System (ADS)

We are developing monolithic backside illuminated CMOS detectors as soft X-ray imaging spectrometers for high energy astrophysics missions. These devices represent a significant advance over CCD technology and have unique properties that would make them ideal sensors for various planetary mission concepts. The benefits of CMOS include higher levels of integration which provide maximum pixel gain and therefore very low noise, very fast parallel output signal chains for high frame rates. CMOS imaging detectors have zero or one charge transfer so that they can withstand many orders of magnitude more radiation than conventional CCDs before degradation. The capability of high read rates provides dynamic range and temporal resolution. Additionally, the rapid read rates minimize shot noise from thermal dark current and optical light. CMOS detectors can therefore run at warmer temperatures and with ultra-thin optical blocking filters. Thin OBFs provide near unity quantum efficiency below 1 keV, thus maximizing response at the C and O lines. Possible mission concepts for these sensors include X-ray fluorescence studies of rocky bodies, and investigation of the magnetospheres of the gas giants and their moons. In this presentation, we discuss the current state of our technology development and outline its scientific potential for planetary physics with particular emphasis on studies of the Jovian magnetosphere. We contrast the capabilities of our instrument with that which has been achieved by the current generation of Earth-orbiting X-ray observatories.

Kraft, Ralph P.; Kenter, A.; Murray, S.; Elvis, M.; Branduardi-Raymont, G.; Garcia, M.; Forman, W.; Geary, J.; McCoy, T.; Smith, R.

2012-10-01

97

Kinoform Optics Applied to X-ray Photon Correlation Spectroscopy  

NASA Astrophysics Data System (ADS)

Moderate de-magnification, higher order silicon kinoform focusing lenses have been fabricated via e-beam lithography and deep etching to facilitate small-angle hard-x-ray photon correlation spectroscopy (XPCS) experiments. Typical lenses have focal lengths of one meter, focus in the vertical direction to within 80% of the diffraction limit and have vertical acceptance apertures of 400 microns. The acceptance in the orthogonal (etch) direction is 50 microns. The measured efficiency of the lenses is 35% and the flux gain at the focal line is 50. We discuss the effect of focusing on the resulting x-ray speckles. We conclude that one-dimensional vertical x-ray focusing via present-generation silicon kinoform lenses increases the usable coherent flux from third-generation storage-ring light sources for small-angle XPCS experiments by a factor of 3. We also discuss the prospects for further improvements in efficiency via diamond or lower order silicon kinoform lenses.

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

2010-03-01

98

X-ray absorption spectroscopy of liquid surfaces  

NASA Astrophysics Data System (ADS)

By combining synchrotron-based x-ray spectroscopy with liquid microjets, we have developed new techniques for the investigation of the geometric and electronic structure of volatile liquid surfaces. An endstation has been constructed to allow windowless introduction of volatile liquids to the UHV environment of synchrotron soft x-ray beamlines (Advanced Light Source, LBL). The high vacuum (10-5 torr) obtained in the photon-microjet interaction volume, allows the use of standard surface science charged particle detection to analyze the ions and electrons produced via core-level excitation. The difference in escape depths of ions and electrons from condensed phase samples yields convenient surface-bulk contrast via the total ion (TIY) (˜5 A) versus the total electron (TEY) (˜20--50 A) yields. This contrast has been exploited in an effort to understand the surface hydrogen bond structure of liquid water and methanol. The temperature profile of these microjets has been characterized under the high vacuum conditions essential for measuring x-ray absorption "action" spectra. We find only moderate cooling of larger diameter (>10 microns) microjets, while smaller jets undergo rapid evaporation, yielding liquid water temperatures as low as -36°C. Extended x-ray absorption fine structure (EXAFS) is a common technique that is an ideal probe of local "liquid structure" (near neighbor distance, coordination numbers, etc.). Moreover, the EXAFS TIY and TEY "action" spectra allow the direct comparison of surface and bulk liquid properties. In both liquid water and methanol, a sizable surface relaxation of the intermolecular O-O distance is observed. On average water molecules at the liquid surface are ˜6% further apart than their bulk counterparts. Near edge x-ray absorption fine structure (NEXAFS) has been shown to be extremely sensitive to not only to the formation of hydrogen bonds, but more importantly to the detailed nature (acceptor vs. donor) of such bonds. TIY NEXAFS spectra combined with DFT analysis has yielded evidence for at least two different species at the liquid water surface. The sharp spectral structure in the TIY signal provides a clear fingerprint for "acceptor-only" H2O molecules at the liquid water interface. Analysis of mass-selected NEXAFS spectra provide corroborating evidence for surface single donor molecules that have been previously identified by SFG spectroscopy. (Abstract shortened by UMI.)

Wilson, Kevin Roger

99

Fluorescence X-ray micro-spectroscopy activities at ESRF  

NASA Astrophysics Data System (ADS)

The X-ray Microscopy and Micro-analysis beamlines at ESRF operate complementary state-of-the-art instruments at ID21, ID22, ID18F and more recently ID22NI. Within a multi-modal strategy, these beamlines develop micro-imaging techniques with various contrast mechanisms (?XRF, ?XANES, ?XRD and phase contrast) and host experiments with scientific topics ranging from Geochemistry to Archeology, Environmental sciences, Biology and Material sciences. Future challenges include pushing spatial resolution down to the nano-scale and the development of innovative 3D micro-analysis techniques.

Salomé, M.; Bleuet, P.; Bohic, S.; Cauzid, J.; Chalmin, E.; Cloetens, P.; Cotte, M.; De Andrade, V.; Martinez-Criado, G.; Petitgirard, S.; Rak, M.; Sans Tresserras, J. A.; Szlachetko, J.; Tucoulou, R.; Susini, J.

2009-09-01

100

Pushing the boundaries of x-ray grating spectroscopy in a suborbital rocket  

NASA Astrophysics Data System (ADS)

The Off-Plane Grating Rocket Experiment (OGRE) will greatly advance the current capabilities of soft X-ray grating spectroscopy and provide an important technological bridge towards future X-ray observatories. The OGRE sounding rocket will fly an innovative X-ray spectrograph operating at resolving powers of R ~ 2000 and effective areas < 100 cm2 in the 0.2-1.5 keV bandpass. This represents a factor of two improvement in spectral resolution over currently operating instruments. OGRE will observe the astrophysical X-ray calibration source Capella, which has a linedominated spectrum and will showcase the full capabilities of the OGRE spectrograph. We outline the mission design for OGRE and provide detailed overviews of relevant technologies to be integrated into the payload, including slumped glass mirrors, blazed reflection gratings customized for the off-plane mount, and electron-multiplying CCDs (EMCCDs). The OGRE mission will bring these components to a high technology readiness level, paving the way for the use of such a spectrograph on future X-ray observatories or Explorer-class missions.

DeRoo, Casey; McEntaffer, Randall L.; Schultz, Ted; Zhang, William W.; Murray, Neil J.; O'Dell, Stephen L.; Cash, Webster

2013-09-01

101

Electronic structure of LaSrMnO4: X-ray photoelectron spectroscopy and x-ray emission spectroscopy studies  

NASA Astrophysics Data System (ADS)

We present a comprehensive investigation of the valence band of the single-layered manganite LaSrMnO4. X-ray photoelectron spectroscopy and x-ray emission spectroscopy were used to reveal a detailed picture of the total and partial densities of states in this compound. The results are discussed in the light of available theory.

Kuepper, K.; Klingeler, R.; Reutler, P.; Büchner, B.; Neumann, M.

2006-04-01

102

Near Edge X-Ray Absorption Fine Structure Spectroscopy with X-Ray Free-Electron Lasers  

SciTech Connect

We demonstrate the feasibility of Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy on solids by means of femtosecond soft x-ray pulses from a free-electron laser (FEL). Our experiments, carried out at the Free-Electron Laser at Hamburg (FLASH), used a special sample geometry, spectrographic energy dispersion, single shot position-sensitive detection and a data normalization procedure that eliminates the severe fluctuations of the incident intensity in space and photon energy. As an example we recorded the {sup 3}D{sub 1} N{sub 4,5}-edge absorption resonance of La{sup 3+}-ions in LaMnO{sub 3}. Our study opens the door for x-ray absorption measurements on future x-ray FEL facilities.

Bernstein, D.P.; Acremann, Y.; Scherz, A.; Burkhardt, M.; Stohr, J.; /SLAC; Beye, M.; Schlotter, W.F.; Beeck, T.; Sorgenfrei, F.; Pietzsch, A.; Wurth, W.; Fohlisch, A.; /Hamburg U.

2009-12-11

103

The Future of X-ray Spectroscopy of Galactic Black Hole Binaries  

NASA Astrophysics Data System (ADS)

There are four major X-ray satellites currently in operation (RXTE, Chandra, XMM-Newton, INTEGRAL), with two more shortly to follow (Astro E II, Swift), and several very ambitious observatories in various stages of planning (Constellation-X, MAXIM, XEUS). This very rich period of X-ray observation is leading to great advances in our understanding of the accretion flow onto the black hole, although we are quickly learning (or perhaps better put, remembering) exactly how complicated this flow can be. This review was meant to assess future prospects for X-ray spectroscopy of black hole binaries; however, I first look backward to the observations and theories that helped us arrive at our current `paradigm'. I then discuss current and near-future spectroscopic studies, which increasingly (and very fruitfully) treat X-ray spectroscopy as part of a larger, intimately connected picture along with radio, optical, and gamma-ray spectroscopy. Equally importantly, and in large part thanks to the success of RXTE, there is now a strong realization that spectral-temporal correlations, even across wavelength bands, are crucial to our understanding of the physics of these systems. Going forward, we are well-poised to continue to advance our knowledge via X-ray spectroscopy, both with existing satellites that have a long lifetime ahead of them (Chandra, XMM-Newton, INTEGRAL), and with the next generation of instruments. If there is any `hole' in this bright future, it is the potential loss of RXTE, with no designated follow-up mission. Studies of multi-wavelength spectral-temporal correlations will become more difficult due to the loss of two important attributes of RXTE: its fast timing capabilities and its extremely flexible scheduling which has made many of these studies possible.

Nowak, Michael A.

2004-07-01

104

Instrument data processing unit for spectrometer/telescope for imaging x-rays (STIX)  

NASA Astrophysics Data System (ADS)

The Spectrometer/Telescope for Imaging X-rays (STIX) is one of 10 instruments on board Solar Orbiter, an M-class mission of the European Space Agency (ESA) scheduled to be launch in 2017. STIX applies a Fourier-imaging technique using a set of tungsten grids in front of 32 pixelized CdTe detectors to provide imaging spectroscopy of solar thermal and non-thermal hard X-ray emissions from 4 to 150 keV. These detectors are source of data collected and analyzed in real-time by Instrument Data Processing Unit (IDPU). Besides the data processing the IDPU controls and manages other STIX’s subsystems: ASICs and ADCs associated with detectors, Aspect System, Attenuator, PSU and HK. The instrument reviewed in this paper is based on the design that passed the Instrument Preliminary Design Review (IPDR) in early 2012 and Software Preliminary Design Review (SW PDR) in middle of 2012. Particular emphasis is given to the IDPU and low level software called Basic SW (BSW).

Skup, Konrad R.; Cichocki, A.; Graczyk, R.; Michalska, M.; Mosdorf, M.; Nowosielski, W.; Orlea?ski, P.; Przepiórka, A.; Seweryn, K.; Stolarski, M.; Winkler, M.; Sylwester, J.; Kowalinski, M.; Mrozek, T.; Podgorski, P.; Benz, A. O.; Krucker, S.; Hurford, G. J.; Arnold, N. G.; Önel, H.; Meuris, A.; Limousin, O.; Grimm, O.

2012-05-01

105

Instrumentation for Microfabrication with Deep X-ray Lithography  

NASA Astrophysics Data System (ADS)

Deep X-ray lithography for microfabrication is performed at least at ten synchrotron radiation centers worldwide. The characteristic energies of these sources range from 1.4 keV up to 8 keV, covering mask making capabilities, deep X-ray lithography up to ultra deep x-ray lithography of several millimeters resist thickness. Limitations in deep X-ray lithography arise from hard X-rays in the SR-spectrum leading to adhesion losses of resist lines after the developing process, as well as heat load due to very high fluxes leading to thermal expansion of mask and resist during exposure and therefore to microstructure distortion. Considering the installations at ANKA as an example, the advantages of mirrors and central beam stops for DXRL are presented. Future research work will concentrate on feature sizes much below 1 ?m, while the commercialization of DXRL goes in the direction of massive automation, including parallel exposures of several samples in a very wide SR-fan, developing and inspection.

Pantenburg, F. J.

2007-01-01

106

Instrumentation for Microfabrication with Deep X-ray Lithography  

SciTech Connect

Deep X-ray lithography for microfabrication is performed at least at ten synchrotron radiation centers worldwide. The characteristic energies of these sources range from 1.4 keV up to 8 keV, covering mask making capabilities, deep X-ray lithography up to ultra deep x-ray lithography of several millimeters resist thickness. Limitations in deep X-ray lithography arise from hard X-rays in the SR-spectrum leading to adhesion losses of resist lines after the developing process, as well as heat load due to very high fluxes leading to thermal expansion of mask and resist during exposure and therefore to microstructure distortion. Considering the installations at ANKA as an example, the advantages of mirrors and central beam stops for DXRL are presented. Future research work will concentrate on feature sizes much below 1 {mu}m, while the commercialization of DXRL goes in the direction of massive automation, including parallel exposures of several samples in a very wide SR-fan, developing and inspection.

Pantenburg, F. J. [Forschungszentrum Karlsruhe GmbH, Institut fuer Mikrostrukturtechnik, Postfach 3640, D- 76021 Karlsruhe (Germany)

2007-01-19

107

Hard x-ray Imaging and Spectroscopy of Long Pulse NIF Hohlraums.  

National Technical Information Service (NTIS)

Summary: Results from the hard x-ray Instruments fielded at NIF in recent shot campaign are discussed ( Filter Fluorescer Experiment (FFLEX), 10 keV x-ray Imager (HXRI)); Data in the form of Hard x-ray spectra and images were collected from these instrume...

E. Dewald J. Foster J. P. Holder J. R. Celeste J. W. McDonald L. J. Suter M. B. Schneider O. L. Landen R. L. Kauffman

2005-01-01

108

XEUS - the X-ray Evolving Universe Spectroscopy Mission  

NASA Astrophysics Data System (ADS)

XEUS is a potential follow-on to XMM-Newton, ESA's Cornerstone X-Ray Spectroscopy Mission currently in operation, and is under study as part of the Horizon 2000+ plan to utilize the International Space Station (ISS) for astronomical applications. XEUS will be a long-term X-ray observatory with an initial aperture of 6 m^2, an energy range of 0.05-30 keV and a spatial resolution of 2" to 5" at 1 keV. The focal plane detectors will consist of both narrow and wide-field imagers with fields of view of 1 and 5-10', respectively. The narrow field imagers are expected to have an energy resolution of <2 eV at 1 keV and the wide field imager 50 eV at 1 keV. Following refurbishment at the ISS the mirror area of 30 m^2 at 1 keV will allow sources as faint as 4 10^-18 erg cm^-2 s^-1 to be detected. The enormous low-energy collecting area and good spatial resolution of XEUS will allow the detection of massive black holes in the earliest AGN and estimates of their mass, spin and redshift through studies of relativistically broadened Fe-K lines and variability to be made. XEUS will allow the study of the formation of the first gravitationally bound, dark matter dominated, systems ie. small groups of galaxies and the tracing of their evolution into today's massive clusters. High resolution spectroscopy will allow the study of the evolution of metal synthesis down to the present epoch, using in particular, observations of the hot intra-cluster gas while the hot filamentary structure will be studied using absorption line spectroscopy to allow the mass, temperature and density of the intergalactic medium to be characterized.

Parmar, A.; Hasinger, G.; Turner, M.

109

(Diffraction gratings used in x-ray spectroscopy): Final report  

SciTech Connect

This subcontract was initiated in order to facilitate the development at MIT of technologies for fabricating the very fine diffraction grating required in x-ray spectroscopy at Lawrence Livermore Laboratory (LLL). These gratings are generally gold transmission gratings with spatial periods of 200 nm or less. The major focus of our efforts was to develop a means of fabricating gratings of 100 nm period. We explored two approaches: e-beam fabrication of x-ray lithography masks, and achromatic holographic lithography. This work was pursued by Erik Anderson as a major component of his Ph.D. thesis. Erik was successful in both the e-beam and holographic approaches. However, the e-beam method proved to be highly impractical: exposure times of about 115 days would be required to cover an area of 1 cm/sup 2/. The achromatic holography, on the other hand, should be capable of exposing areas well in excess of 1 cm/sup 2/ in times under 1 hour. Moreover, 100 nm-period gratings produced by achromatic holography are coherent over their entire area whereas gratings produced by e-beam lithography are coherent only over areas /approximately/100 ..mu..m. The remainder of this report consists of portions excerpted from Erik Anderson's thesis. These contain all the details of our work on 100 nm period gratings. 26 refs., 17 figs.

Smith, H.I.

1988-11-01

110

X-Ray Absorption Spectroscopy Imaging of Biological Tissues  

SciTech Connect

X-ray absorption spectroscopy (XAS) is proving invaluable in determining the average chemical form of metals or metalloids in intact biological tissues. As most tissues have spatial structure, there is great additional interest in visualizing the spatial location of the metal(loid) as well as its chemical forms. XAS imaging gives the opportunity of producing maps of specific chemical types of elements in vivo in dilute biological systems. X-ray fluorescence microprobe techniques are routinely used to study samples with spatial heterogeneity. Microprobe produces elemental maps, with chemical sensitivity obtained by recording micro-XAS spectra at selected point locations on the map. Unfortunately, using these procedures spatial detail may be lost as the number of point spectra recorded generally is limited. A powerful extension of microprobe is XAS imaging or chemically specific imaging. Here, the incident energy is tuned to features in the near-edge which are characteristic of the expected chemical forms of the element. With a few simple assumptions, these XAS images can then be converted to quantitative images of specific chemical form, yielding considerable clarity in the distributions.

Pickering, I.J.; George, G.N.

2009-06-05

111

X-Ray Absorption Spectroscopy Imaging of Biological Tissues  

SciTech Connect

X-ray absorption spectroscopy (XAS) is proving invaluable in determining the average chemical form of metals or metalloids in intact biological tissues. As most tissues have spatial structure, there is great additional interest in visualizing the spatial location of the metal(loid) as well as its chemical forms. XAS imaging gives the opportunity of producing maps of specific chemical types of elements in vivo in dilute biological systems. X-ray fluorescence microprobe techniques are routinely used to study samples with spatial heterogeneity. Microprobe produces elemental maps, with chemical sensitivity obtained by recording micro-XAS spectra at selected point locations on the map. Unfortunately, using these procedures spatial detail may be lost as the number of point spectra recorded generally is limited. A powerful extension of microprobe is XAS imaging or chemically specific imaging. Here, the incident energy is tuned to features in the near-edge which are characteristic of the expected chemical forms of the element. With a few simple assumptions, these XAS images can then be converted to quantitative images of specific chemical form, yielding considerable clarity in the distributions.

Pickering, Ingrid J.; George, Graham N. [Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK, S7N 4R5 (Canada)

2007-02-02

112

X-Ray Absorption Spectroscopy Imaging of Biological Tissues  

NASA Astrophysics Data System (ADS)

X-ray absorption spectroscopy (XAS) is proving invaluable in determining the average chemical form of metals or metalloids in intact biological tissues. As most tissues have spatial structure, there is great additional interest in visualizing the spatial location of the metal(loid) as well as its chemical forms. XAS imaging gives the opportunity of producing maps of specific chemical types of elements in vivo in dilute biological systems. X-ray fluorescence microprobe techniques are routinely used to study samples with spatial heterogeneity. Microprobe produces elemental maps, with chemical sensitivity obtained by recording micro-XAS spectra at selected point locations on the map. Unfortunately, using these procedures spatial detail may be lost as the number of point spectra recorded generally is limited. A powerful extension of microprobe is XAS imaging or chemically specific imaging. Here, the incident energy is tuned to features in the near-edge which are characteristic of the expected chemical forms of the element. With a few simple assumptions, these XAS images can then be converted to quantitative images of specific chemical form, yielding considerable clarity in the distributions.

Pickering, Ingrid J.; George, Graham N.

2007-02-01

113

Correlated Single-Crystal Electronic Absorption Spectroscopy and X-ray Crystallography at NSLS Beamline X26-C  

SciTech Connect

The research philosophy and new capabilities installed at NSLS beamline X26-C to support electronic absorption and Raman spectroscopies coupled with X-ray diffraction are reviewed. This beamline is dedicated full time to multidisciplinary studies with goals that include revealing the relationship between the electronic and atomic structures in macromolecules. The beamline instrumentation has been fully integrated such that optical absorption spectra and X-ray diffraction images are interlaced. Therefore, optical changes induced by X-ray exposure can be correlated with X-ray diffraction data collection. The installation of Raman spectroscopy into the beamline is also briefly reviewed. Data are now routinely generated almost simultaneously from three complementary types of experiments from the same sample. The beamline is available now to the NSLS general user population.

A Orville; R Buono; M Cowan; A Heroux; G Shea-McCarthy; D Schneider; J Skinner; M Skinner; D Stoner-Ma; R Sweet

2011-12-31

114

Correlated single-crystal electronic absorption spectroscopy and X-ray crystallography at NSLS beamline X26-C  

SciTech Connect

The research philosophy and new capabilities installed at NSLS beamline X26-C to support electronic absorption and Raman spectroscopies coupled with X-ray diffraction are reviewed. This beamline is dedicated full time to multidisciplinary studies with goals that include revealing the relationship between the electronic and atomic structures in macromolecules. The beamline instrumentation has been fully integrated such that optical absorption spectra and X-ray diffraction images are interlaced. Therefore, optical changes induced by X-ray exposure can be correlated with X-ray diffraction data collection. The installation of Raman spectroscopy into the beamline is also briefly reviewed. Data are now routinely generated almost simultaneously from three complementary types of experiments from the same sample. The beamline is available now to the NSLS general user population.

Orville, A.M.; Buono, R.; Cowan, M.; Heroux, A.; Shea-McCarthy, G.; Schneider, D. K.; Skinner, J. M.; Skinner, M. J.; Stoner-Ma, D.; Sweet, R. M.

2011-05-01

115

Correlated single-crystal electronic absorption spectroscopy and X-ray crystallography at NSLS beamline X26-C  

PubMed Central

The research philosophy and new capabilities installed at NSLS beamline X26-C to support electronic absorption and Raman spectroscopies coupled with X-ray diffraction are reviewed. This beamline is dedicated full time to multidisciplinary studies with goals that include revealing the relationship between the electronic and atomic structures in macromolecules. The beamline instrumentation has been fully integrated such that optical absorption spectra and X-ray diffraction images are interlaced. Therefore, optical changes induced by X-ray exposure can be correlated with X-ray diffraction data collection. The installation of Raman spectroscopy into the beamline is also briefly reviewed. Data are now routinely generated almost simultaneously from three complementary types of experiments from the same sample. The beamline is available now to the NSLS general user population.

Orville, Allen M.; Buono, Richard; Cowan, Matt; Heroux, Annie; Shea-McCarthy, Grace; Schneider, Dieter K.; Skinner, John M.; Skinner, Michael J.; Stoner-Ma, Deborah; Sweet, Robert M.

2011-01-01

116

X-Ray Spectroscopy of the Liquid Water Surface  

NASA Astrophysics Data System (ADS)

We have developed a new experiment for probing molecular details of liquid-vapor interfaces of volatile substances and their solutions under equilibrium conditions. Electronic and geometric structures of interfacial molecules are probed by EXAFS and NEXAFS methods in the soft X-ray region, using the Advanced Light Source, Berkeley, CA. Liquids are introduced into a high vacuum environment through the use of liquid microjets, which have been characterized independently by Raman spectroscopy. Detection of ions and electrons produced by the Auger avalanche probe the bulk and surface regions of the microjet, respectively, as a result of their different escape depths. Our first efforts involved a comparative study of the interfaces of water and methanol, wherein we detailed the first observation of surface relaxation for a liquid. Analysis of EXAFS data yielded a 6distance at the water interface, whereas a 5was found for methanol. NEXAFS measurements, interpreted in terms of density functional theory simulations, indicate a large population of interfacial water molecules having two free OH bonds ("acceptor only molecules"). This complements the "single donor" species identified in sum frequency generation experiments. These results are supported by recent theoretical calculations. For methanol and other simple alcohols, the data indicate that free alkyl groups extend into the vapor part of the interface. Preliminary results for aqueous solutions, as well as for other pure liquids, have been obtained and are presently under analysis. REFERENCES 1. K.R. Wilson, R.D. Schaller, B.S. Rude, T. Catalano, D.T. Co, J.D. Bozek, and R.J. Saykally, "Surface relaxation in liquid water and methanol studied by X-ray absorption spectroscopy," J. Chem. Phys 117,7738(2002). 2. K.R. Wilson, M. Cavalleri, B.S. Rude, R.D. Schaller, A. Nilsson, L.G.M. Pettersson, N. Goldman, T. Catalano, J.D. Bozek, and R.J. Saykally, "Characterization of hydrogen bond acceptor molecules at the water surface using near-edge x-ray absorption fine-structure spectroscopy and density functional theory," J. Phys.: Condens. Matter 14, L221-L226 (2002).

Saykally, Richard

2004-03-01

117

Synchrotron Radiation X-Ray Spectroscopy for Investigations of Intracellular Metallointercalators: X-Ray Fluorescence Imaging and X-Ray Absorption Spectroscopy  

NASA Astrophysics Data System (ADS)

In an effort to determine the therapeutic feasibility of DNA metallointercalators as potential anticancer drugs it is important to confirm that they are capable of targeting DNA in cancer cells or tumours - as is the intended purpose of their design. Microprobe synchrotron radiation X-ray fluorescence (micro-SRXRF) spectroscopy is an ideal technique for investigating the cellular uptake and distribution of metallointercalators. The technique is capable of submicron elemental imaging so that samples as small as individual cells (~10 ?m diameter), and the features within them, can be resolved. Consequently, the technique can ascertain whether intracellular metallointercalators colocalise with DNA; namely, in the nucleus during interphase or at the chromosomes during middle prophase to late anaphase. Metals, such as those commonly incorporated into metallointercalators (e.g., Cr, Ni, Co, Pd, Pt, Ru, Rh), are often naturally present in negligible quantities in cancer cells. This fact, together with their higher atomic number, Z, makes them ideal for direct probing using hard X-ray microprobes (as discussed in Sect. 11.2). There is no need for the incorporation of fluorescent tracker dyes or radioactive labels into their chemical structure. This is advantageous since it is unknown whether such chemical modifications alter the uptake kinetics of the metallointercalator [1, 2].

Dillon, Carolyn T.

118

28 CFR 552.13 - X-ray, major instrument, fluoroscope, or surgical intrusion.  

Code of Federal Regulations, 2010 CFR

...CUSTODY Searches of Housing Units, Inmates, and Inmate Work Areas § 552.13 X-ray, major instrument, fluoroscope...consent is not required. (c) The Warden may direct X-rays of inanimate objects where the inmate is not...

2010-07-01

119

28 CFR 552.13 - X-ray, major instrument, fluoroscope, or surgical intrusion.  

Code of Federal Regulations, 2010 CFR

...CUSTODY Searches of Housing Units, Inmates, and Inmate Work Areas § 552.13 X-ray, major instrument, fluoroscope...consent is not required. (c) The Warden may direct X-rays of inanimate objects where the inmate is not...

2009-07-01

120

High-Resolution X-ray Spectroscopy Close to Room Temperature  

NASA Astrophysics Data System (ADS)

: Originally designed as position-sensitive detectors for particle tracking, silicon drift detectors (SDDs) are now used for high-count rate X-ray spectroscopy, operating close to room temperature. Their low-capacitance read-node concept places them among the fastest high-resolution detector systems. They have been used in a new spectrum of experiments in the wide field of X-ray spectroscopy: fluorescent analysis, diffractometry, materials analysis, and synchrotron experiments such as X-ray holography and element imaging in scanning electron microscopes. The fact that the detector system can be used at room temperature with good spectroscopic performance and at [minus sign]10°C with excellent energy resolution, avoiding liquid nitrogen for cooling and high-quality vacuum, guarantees a large variety of new applications, independent of the laboratory environment. A brief description of the device principles is followed by basics on low noise amplification. The performance results of a complete detector system are presented as well as some dedicated applications already realized, including use in a surface mapping instrument and use of a ``mini-spectrometer'' for the analysis of works of art. Fully depleted pn-charge-coupled devices (pn-CCDs) have been fabricated for the European X-ray Multi-Mirror mission (XMM) and the German X-ray satellite ABRIXAS, enabling high-speed, low-noise, position-resolving X-ray spectroscopy. The detector was designed and fabricated with a homogeneously sensitive area of 36 cm2. At [minus sign]70°C it has a noise of 4 e- rms, with a readout time of the total focal plane array of 4 msec. The maximum count rate for single photon counting was 105 cps under flat field conditions. In the integration mode, more than 109 cps can be detected at 6 keV. Its position resolution is on the order of 100 [mu]m. The quantum efficiency is higher than 90%, ranging from carbon K X-rays (277 eV) up to 10 keV.

Strüder, L.; Meidinger, N.; Stotter, D.; Kemmer, J.; Lechner, P.; Leutenegger, P.; Soltau, H.; Eggert, F.; Rohde, M.; Schulein, T.

1998-11-01

121

High Resolution X-Ray Imaging and Spectroscopy of AGN and SS 433 with the Chandra X-Ray Observatory  

NASA Astrophysics Data System (ADS)

We present some early results on AGN and jets with the Chandra X-ray Observatory, highlighting high resolution spectroscopy using the High Energy Transmission Grating Spectrometer (HETGS). The quasar PKS 0637--752 was found to have a very bright X-ray jet whose shape is remarkably similar to that of the radio jet on a size scale of 100 kpc but the X-ray emission is still unexplainably bright. Two BL Lac objects, PKS 2155--304 and Mk 421, were observed with the spectrometer and found to have no strong absorption or emission features. Other radio loud AGN observed with the HETGS show simple power law spectra without obvious features. These AGN results stand in marked contrast to the line-rich spectrum of SS 433, a Galactic X-ray binary which has relativistic jets. Broadened X-ray emission lines of H- and He-like S and Si are used to show that the characteristic temperature of the jet is near 2.5 keV at its base.

Marshall, H. L.

2000-04-01

122

Powerful microfocus x-ray and hard x-ray 1 MA x-pinch plasma source for imaging, spectroscopy, and polarimetry  

Microsoft Academic Search

The x-ray emission of Ti, Fe, Mo, W and Pt x-pinches are currently bieng studied at the Nevada Terawatt Facility z- pinch machine (0.9-1.0 MA, 100 ns). New x-ray diagnostics for time-resolved spectroscopy and imaging has been developed and used in x-pinch experiments. The total x- ray\\/EUV yield was more than 10 kJ. The minimum x-ray pulse duration was 1.1

Victor L. Kantsyrev; Bruno S. Bauer; Alla S. Shlyaptseva; Dmitri A. Fedin; Stephanie Hansen; Radu Presura; Stephan Fuelling; Steve Batie; Andrew Oxner; Harold Faretto; Nick D. Ouart; Sean Keely; Hank LeBeau; David Chamberlain

2001-01-01

123

Software System for the Calibration of X-Ray Measuring Instruments  

SciTech Connect

A software system that facilities the calibration of X-ray measuring instruments used in medical applications is presented. The Secondary Standard Dosimetry Laboratory (SSDL) of the Nuclear Research National Institute in Mexico (ININ in Spanish), supports activities concerning with ionizing radiations in medical area. One of these activities is the calibration of X-ray measuring instruments, in terms of air kerma or exposure by substitution method in an X-ray beam at a point where the rate has been determined by means of a standard ionization chamber. To automatize this process, a software system has been developed, the calibration system is composed by an X-ray unit, a Dynalizer IIIU X-ray meter by RADCAL, a commercial data acquisition card, the software system and the units to be tested and calibrated. A quality control plan has been applied in the development of the software system, ensuring that quality assurance procedures and standards are being followed.

Gaytan-Gallardo, E.; Tovar-Munoz, V. M.; Cruz-Estrada, P.; Vergara-Martinez, F. J.; Rivero-Gutierrez, T. [Instituto National de Investigaciones Nucleares Carretera Mexico-Toluca s/n. La Marquesa, Ocoyoacac, 52750 (Mexico)

2006-09-08

124

Application of X-ray synchrotron microscopy instrumentation in biology  

SciTech Connect

X-ray micro-fluorescence imaging technique has been used as a significant tool in order to investigate minerals contents in some kinds of materials. The aim of this study was to evaluate the elemental distribution of calcium and zinc in bone substitute materials (nano-hydroxyapatite spheres) and cortical bones through X-Ray Micro-fluorescence analysis with the increment of Synchrotron Radiation in order to evaluate the characteristics of the newly formed bone and its interface, the preexisting bone and biomaterials by the arrangement of collagen fibers and its birefringence. The elemental mapping was carried out at Brazilian Synchrotron Light Laboratory, Campinas - Sao Paulo, Brazil working at D09-XRF beam line. Based on this study, the results suggest that hydroxyapatite-based biomaterials are biocompatible, promote osteo-conduction and favored bone repair. (authors)

Gasperini, F. M. [Medical Science Program, Fluminense Federal Univ., Niteroi (Brazil); Pereira, G. R. [Dept. of Metallurgical and Materials Engineering, Federal Univ. of Rio de Janeiro (Brazil); Granjeiro, J. M. [Molecular and Cell Biology Dept., Fluminense Federal Univ., Niteroi, Rio de Janeiro (Brazil); Calasans-Maia, M. D. [Oral Surgery Dept., Fluminense Federal Univ., Niteroi, Rio de Janeiro (Brazil); Rossi, A. M. [Biomaterials Laboratory, Brazilian Center of Physics Research, Rio de Janeiro (Brazil); Perez, C. A. [Brazilian Synchrotron Laboratory, Campinas, Sao Paulo (Brazil); Lopes, R. T.; Lima, I. [Nuclear Engineering Laboratory, Federal Univ. of Rio de Janeiro (Brazil)

2011-07-01

125

X-ray absorption spectroscopy of bacterial sulfur globules  

SciTech Connect

Sulfur K-edge X-ray absorption spectroscopy is a powerful in situ probe of sulfur biochemistry in intact cells and tissues. Under favorable circumstances the technique can provide quantitative information on the chemical identify of the sulfur species that are present in a sample. Prange et al. have recently reported an X-ray absorption spectroscopic study of bacterial sulfur storage globules. Unfortunately there are substantial problems with the experimental technique employed that, they contend, lead to completely erroneous conclusions. In the more recent of their two papers Prange et al. employed a curve-fitting method similar to that used by us (for more than 10 years). In essence, the method employs simply fitting a linear combination of the spectra of standard compounds to that of the unknown, in this case cultures of bacterial cells. This type of analysis can provide quantitative estimates of the individual sulfur types in the sample, but is critically dependent upon the choice of reference spectra. Prange et al. deduce substantial differences between the chemical forms of sulfur stored in the globules of different organisms; they conclude that the globules of Beggiatoa alba and Thiomargarita namibiensis contain cyclo-octasulfur (S{sub 8}), while those of other organisms contain polythionates (Acidithiobacillus ferrooxidans) and polymeric sulfur (e.g. Allochromatium vinosum). This is in contradiction with an earlier study, in which they found that sulfur in all globule species examined resembled that expected for various sized spherical particles of S{sub 8}. The discrepancy is due to an experimental artefact in the work of Prange et al. arising from their choice of transmittance detection, which is also discussed.

George, Graham N.

2002-08-01

126

New Developments in Data for Auger Electron Spectroscopy and X- ray Photoelectron Spectroscopy  

Microsoft Academic Search

A brief description is given of three recent developments concerning the generation and application of data for elastic and inelastic scattering of electrons relevant to Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy. First, an extensive analysis of calculated and measured differential cross sections for elastic scattering of electrons by atoms has been published. Second, new calculations have been made of

C. J. Powell; A. Jablonski; F. Salvat; S. Tanuma; D. R. Penn

127

High spatial resolution x-ray spectroscopy with the XM-1 X-ray microscope  

NASA Astrophysics Data System (ADS)

The XM-1 x-ray microscope was built to obtain high-resolution transmission images from a wide variety of thick (< 10 micron) samples. Modeled after a ``conventional'' full-field microscope, XM-1 makes use of zone plates (ZP) for the condenser and objective elements. The XM-1 x-ray microscope has been shown to have a spatial resolution of 36 nm by doing a 10%-90% edge scan across a knife edge. Moreover, the condenser ZP and pinhole combination yields good spectral resolution to ?/?? of 700. We have shown that with this energy resolution we can distinguish between different elements and some chemical states. We can see spectra with adequate signal to noise even for individual 36nm pixels. With these capabilities, we are beginning work on various experiments in which we will distinguish different chemical species of specific elements within a sample. .

Johnson, Lewis E.; Denbeaux, Greg; Meyer-Ilse, Werner

2000-06-01

128

Quantum wave packet revivals in IR + X-ray pump–probe spectroscopy  

Microsoft Academic Search

The wave packet revivals constitute a central concept of X-ray spectroscopy with ultra-high spectral resolution. The revival phenomenon allows to resolve the anharmonical shift or rotational structure by means of time dependent measurements and makes X-ray pump–probe spectroscopy a powerful technique to study long-term dynamics of molecules in different phases. We study the revivals referring to the X-ray absorption spectrum

F. F. Guimaraes; F. Gel’mukhanov; A. Cesar; H. Ågren

2005-01-01

129

Transition metal oxide perovskites by photoelectron and x-ray absorption spectroscopy  

Microsoft Academic Search

X-ray and ultraviolet photoelectron spectroscopy as well as x-ray absorption spectroscopy have been employed to investigate\\u000a transition metal oxide perovskites of the general formula ABO3 (A = La or rare-earth ion, B=trivalent transition metal ion). Systematics in the core levels and in the valence bands in\\u000a the series of LaBO3 compounds have been discussed. Lanthanum chemical shifts in the x-ray

W H Madhusudan; Sheelavathi Kollali; P R Sarode; M S Hegde; P Ganguly; C N R Rao

1979-01-01

130

Fast CCD camera for x-ray photon correlation spectroscopy and time-resolved x-ray scattering and imaging  

SciTech Connect

A new, fast x-ray detector system is presented for high-throughput, high-sensitivity, time-resolved, x-ray scattering and imaging experiments, most especially x-ray photon correlation spectroscopy (XPCS). After a review of the architectures of different CCD chips and a critical examination of their suitability for use in a fast x-ray detector, the new detector hardware is described. In brief, its principal component is an inexpensive, commercial camera - the SMD1M60 - originally designed for optical applications, and modified for use as a direct-illumination x-ray detector. The remainder of the system consists of two Coreco Imaging PC-DIG frame grabber boards, located inside a Dell Power-edge 6400 server. Each frame grabber sits on its own PCI bus and handles data from 2 of the CCD's 4 taps. The SMD1M60 is based on a fast, frame-transfer, 4-tap CCD chip, read out at12-bit resolution at frame rates of up to 62 Hz for full frame readout and up to 500 Hz for one-sixteenth frame readout. Experiments to characterize the camera's suitability for XPCS and small-angle x-ray scattering (SAXS) are presented. These experiments show that single photon events are readily identified, and localized to within a pixel index or so. This is a sufficiently fine spatial resolution to maintain the speckle contrast at an acceptable value for XPCS measurements. The detective quantum efficiency of the SMD1M60 is 49% for directly-detected 6.3 keV x rays. The effects of data acquisition strategies that permit near-real-time data compression are also determined and discussed. Overall, the SMD1M60 detector system represents a major improvement in the technology for time-resolved x-ray experiments, that require an area detector with time-resolutions in few-milliseconds-to-few-seconds range, and it should have wide applications, extending beyond XPCS.

Falus, P.; Borthwick, M.A.; Mochrie, S.G.J. [Department of Physics, Yale University, New Haven, Connecticut 06520 and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Departments of Physics and Applied Physics, Yale University, New Haven, Connecticut 06520 (United States)

2004-11-01

131

Electron Spectroscopy: Ultraviolet and X-Ray Excitation.  

ERIC Educational Resources Information Center

|Reviews recent growth in electron spectroscopy (54 papers cited). Emphasizes advances in instrumentation and interpretation (52); photoionization, cross-sections and angular distributions (22); studies of atoms and small molecules (35); transition, lanthanide and actinide metal complexes (50); organometallic (12) and inorganic compounds (2);…

Baker, A. D.; And Others

1980-01-01

132

Detection limits for actinides in a monochromatic, wavelength-dispersive x-ray fluorescence instrument  

SciTech Connect

Recent developments in x-ray optics have made it possible to examine the L x-rays of actinides using doubly-curved crystals in a bench-top device. A doubly-curved crystal (DCC) acts as a focusing monochromatic filter for polychromatic x-rays. A Monochromatic, Wavelength-Dispersive X-Ray Fluorescence (MWDXRF) instrument that uses DCCs to measure Cm and Pu in reprocessing plant liquors was proposed in 2007 by the authors at Los Alamos National Laboratory. A prototype design of this MWDXRF instrument was developed in collaboration with X-ray Optical Systems Inc. (XOS), of East Greenbush, New York. In the MWDXRF instrument, x-rays from a Rhodium-anode x-ray tube are passed through a primary DCC to produce a monochromatic beam of 20.2-keV photons. This beam is focused on a specimen that may contain actinides. The 20.2-keV interrogating beam is just above the L3 edge of Californium; each actinide (with Z = 90 to 98) present in the specimen emits characteristic L x-rays as the result of L3-shell vacancies. In the LANL-XOS prototype MWDXRf, these x-rays enter a secondary DCC optic that preferentially passes 14.961-keV photons, corresponding to the L-alpha-1 x-ray peak of Curium. In the present stage of experimentation, Curium-bearing specimens have not been analyzed with the prototype MWDXRF instrument. Surrogate materials for Curium include Rubidium, which has a K-beta-l x-ray at 14.961 keV, and Yttrium, which has a K-alpha-1 x-ray at 14.958 keV. In this paper, the lower limit of detection for Curium in the LANL-XOS prototype MWDXRF instrument is estimated. The basis for this estimate is described, including a description of computational models and benchmarking techniques used. Detection limits for other actinides are considered, as well as future safeguards applications for MWDXRF instrumentation.

Collins, Michael L [Los Alamos National Laboratory; Havrilla, George J [Los Alamos National Laboratory

2009-01-01

133

X-ray photon correlation spectroscopy during homogenous shear flow.  

PubMed

We report x-ray photon correlation spectroscopy measurements of advective and diffusive dynamics in a dispersion of colloidal particles subjected to homogeneous shear flow in a rotating-disk shear cell. Intensity autocorrelation functions from scattering data collected using homodyne detection respond to the variation in velocity across the scattering volume when the scattering vector has a component parallel to the flow direction. Theoretical expressions for the impact of homogenous shear flow on the correlation function provide a quantitative prediction of the dependence of correlation functions on the scattering vector and shear rate. Under most circumstances, the applied shear deformation dominates the decay of the intensity correlation function. When scattering data are collected perpendicular to the flow direction, it is possible to measure the diffusive dynamics of the particles free from effects of the superimposed shear flow; however, this approach only works below some upper shear rate limit, beyond which data are affected either by shear effects (caused by the finite width of the detector) or by particle transit through the scattering volume. PMID:22463207

Burghardt, Wesley R; Sikorski, Marcin; Sandy, Alec R; Narayanan, Suresh

2012-02-03

134

A new endstation at the Swiss Light Source for ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy measurements of liquid solutions.  

PubMed

A new liquid microjet endstation designed for ultraviolet (UPS) and X-ray (XPS) photoelectron, and partial electron yield X-ray absorption (XAS) spectroscopies at the Swiss Light Source is presented. The new endstation, which is based on a Scienta HiPP-2 R4000 electron spectrometer, is the first liquid microjet endstation capable of operating in vacuum and in ambient pressures up to the equilibrium vapor pressure of liquid water at room temperature. In addition, the Scienta HiPP-2 R4000 energy analyzer of this new endstation allows for XPS measurements up to 7000 eV electron kinetic energy that will enable electronic structure measurements of bulk solutions and buried interfaces from liquid microjet samples. The endstation is designed to operate at the soft X-ray SIM beamline and at the tender X-ray Phoenix beamline. The endstation can also be operated using a Scienta 5 K ultraviolet helium lamp for dedicated UPS measurements at the vapor-liquid interface using either He I or He II ? lines. The design concept, first results from UPS, soft X-ray XPS, and partial electron yield XAS measurements, and an outlook to the potential of this endstation are presented. PMID:23902081

Brown, Matthew A; Redondo, Amaia Beloqui; Jordan, Inga; Duyckaerts, Nicolas; Lee, Ming-Tao; Ammann, Markus; Nolting, Frithjof; Kleibert, Armin; Huthwelker, Thomas; Müächler, Jean-Pierre; Birrer, Mario; Honegger, Juri; Wetter, Reto; Wörner, Hans Jakob; van Bokhoven, Jeroen A

2013-07-01

135

Electrochemical discharge of nanocrystalline magnetite: structure analysis using X-ray diffraction and X-ray absorption spectroscopy.  

PubMed

Magnetite (Fe3O4) is an abundant, low cost, environmentally benign material with potential application in batteries. Recently, low temperature coprecipitation methods have enabled preparation of a series of nanocrystalline magnetite samples with a range of crystallite sizes. Electrochemical cells based on Li/Fe3O4 show a linear increase in capacity with decreasing crystallite size at voltages ?1.2 V where a 2× capacity improvement relative to commercial (26.2 nm) magnetite is observed. In this report, a combination of X-ray powder diffraction (XRD) and X-ray absorption spectroscopy (XAS) is used to measure magnetite structural changes occurring upon electrochemical reduction, with parent Fe3O4 crystallite size as a variable. Notably, XAS provides evidence of metallic iron formation at high levels of electrochemical reduction. PMID:24077019

Menard, Melissa C; Takeuchi, Kenneth J; Marschilok, Amy C; Takeuchi, Esther S

2013-10-01

136

CdZnTe detector in mammographic x-ray spectroscopy  

Microsoft Academic Search

A CdZnTe (CZT) detector was utilized in mammographic x-ray spectroscopy under clinical conditions. First, the detector response was investigated using gamma-rays from 241Am. The escape of secondary (Compton scattered and K fluorescent) x-rays and tailing due to carrier trapping were minor in the mammographic energy range. In addition, the transmission of primary x-rays was minimal from the results calculated using

Satoshi Miyajima; Kotaro Imagawa

2002-01-01

137

Sulfur Kedge X-ray absorption spectroscopy of petroleum asphaltenes and model compounds  

Microsoft Academic Search

The utility of sulfur K-edge X-ray absorption spectroscopy for the determination and quantification of sulfur forms in petroleum asphaltenes has been investigated. Both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra were obtained for a selected group of model compounds and for several petroleum asphaltene samples. For the model compounds the sulfur XANES was

Graham N. George; Martin L. Gorbaty

1989-01-01

138

X-ray spectroscopy in the EC nucleus  

NASA Astrophysics Data System (ADS)

The probabilities PKK of double K-shell vacancy production per K electron capture decay and per K internal conversion of 109Cd and 207Bi have been determined by means of the double- and triple-coincidence experiments using K? X-ray and K internal conversion. For 109Cd we find PKK(EC) = (4.2+/-0.5)x10-5 and PKK(IC) = (4.32+/-0.46)x10-5, and for 207Bi, PKK(EC) = (2.54+/-0.50)x10-5. The observed X-ray energy shifts of the hypersatellite Ag (K?1H) X-ray and the hypersatellite Pb (K?1H) X-ray lines are 545+/-15 eV and 1238+/-45 eV, respectively.

Ko, Seung Kook; Cho, Hyun Jae; Nha, Sang Kyun

1998-10-01

139

Spectroscopy of six X-ray-selected BL Lacertae candidates  

SciTech Connect

Results of a continuing program aimed at extending the small list of X-ray-selected BL Lac objects are reported. High-quality spectra have been obtained of six faint blue objects that lie within the positional error boxes of X-ray sources discovered serendipitously by the Einstein Observatory. Three of the objects are found to be previously uncataloged low-red-shift quasi-stellar objects, including one formerly suggested as BL Lac candidate. Two are faint galactic stars, while the final object has a featureless spectrum, and thus remains a candidate. Although X-ray selection may ultimately be an effective means of discovering faint BL Lac objects, such sources are evidently rare at the X-ray flux levels attainable by the Einstein Observatory. 15 references.

Margon, B.; Boroson, T.A.; Chanan, G.A.; Thompson, I.B.; Schneider, D.P.

1986-11-01

140

Linac Coherent Light Source soft x-ray materials science instrument optical design and monochromator commissioning  

NASA Astrophysics Data System (ADS)

We present the x-ray optical design of the soft x-ray materials science instrument at the Linac Coherent Light Source, consisting of a varied line-spaced grating monochromator and Kirkpatrick-Baez refocusing optics. Results from the commissioning of the monochromator are shown. A resolving power of 3000 was achieved, which is within a factor of two of the design goal.

Heimann, Philip; Krupin, Oleg; Schlotter, William F.; Turner, Joshua; Krzywinski, Jacek; Sorgenfrei, Florian; Messerschmidt, Marc; Bernstein, David; Chalupský, Jaromir; Hájková, Vera; Hau-Riege, Stefan; Holmes, Michael; Juha, Libor; Kelez, Nicholas; Lüning, Jan; Nordlund, Dennis; Fernandez Perea, Monica; Scherz, Andreas; Soufli, Regina; Wurth, Wilfried; Rowen, Michael

2011-09-01

141

The soft x-ray instrument for materials studies at the linac coherent light source x-ray free-electron laser  

SciTech Connect

The soft x-ray materials science instrument is the second operational beamline at the linac coherent light source x-ray free electron laser. The instrument operates with a photon energy range of 480-2000 eV and features a grating monochromator as well as bendable refocusing mirrors. A broad range of experimental stations may be installed to study diverse scientific topics such as: ultrafast chemistry, surface science, highly correlated electron systems, matter under extreme conditions, and laboratory astrophysics. Preliminary commissioning results are presented including the first soft x-ray single-shot energy spectrum from a free electron laser.

Schlotter, W. F.; Turner, J. J.; Rowen, M.; Holmes, M.; Messerschmidt, M.; Moeller, S.; Krzywinski, J.; Lee, S.; Coffee, R.; Hays, G. [LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025 (United States); Heimann, P. [LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025 (United States); Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Krupin, O. [LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025 (United States); European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); Soufli, R.; Fernandez-Perea, M.; Hau-Riege, S. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Kelez, N. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Beye, M.; Gerken, N.; Sorgenfrei, F.; Wurth, W. [Institute for Experimental Physics and CFEL, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); and others

2012-04-15

142

EUV spectroscopy of high-redshift x-ray objects  

Microsoft Academic Search

As astronomical observations are pushed to cosmological distances (z>3) the spectral energy distributions of X-ray objects, AGN for example, will be redshifted into the EUV waveband. Consequently, a wealth of critical spectral diagnostics, provided by, for example, the Fe L-shell complex and the O VII\\/VIII lines, will be lost to future planned X-ray missions (e.g., IXO, Gen-X) if operated at

M. P. Kowalski; M. T. Wolff; K. S. Wood; T. W. Barbee Jr.; M. A. Barstow

2010-01-01

143

Instrument for x-ray magnetic circular dichroism measurements at high pressures  

SciTech Connect

An instrument has been developed for x-ray magnetic circular dichroism (XMCD) measurements at high pressures and low temperatures. This instrument couples a nonmagnetic copper-beryllium diamond anvil cell featuring perforated diamonds with a helium flow cryostat and an electromagnet. The applied pressure can be controlled in situ using a gas membrane and calibrated using Cu K-edge x-ray absorption fine structure measurements. The performance of this instrument was tested by measuring the XMCD spectra of the Gd{sub 5}Si{sub 2}Ge{sub 2} giant magnetocaloric material.

Haskel, D.; Tseng, Y. C.; Lang, J. C.; Sinogeikin, S. [Magnetic Materials Group, Advanced Photon Source, Argonne National Laboratory, Argonne, lllinois 60439 (United States); HPCAT, Carnegie Institution of Washington, Advanced Photon Source, Argonne National Laboratory, Argonne, lllinois 60439 (United States)

2007-08-15

144

Instrument for x-ray magnetic circular dichroism measurements at high pressures.  

PubMed

An instrument has been developed for x-ray magnetic circular dichroism (XMCD) measurements at high pressures and low temperatures. This instrument couples a nonmagnetic copper-beryllium diamond anvil cell featuring perforated diamonds with a helium flow cryostat and an electromagnet. The applied pressure can be controlled in situ using a gas membrane and calibrated using Cu K-edge x-ray absorption fine structure measurements. The performance of this instrument was tested by measuring the XMCD spectra of the Gd(5)Si(2)Ge(2) giant magnetocaloric material. PMID:17764332

Haskel, D; Tseng, Y C; Lang, J C; Sinogeikin, S

2007-08-01

145

Novel Approaches to Soft X-ray Spectroscopy: Scanning TransmissionX-ray Microscopy and Ambient Pressure X-Ray PhotoelectronSpectroscopy  

SciTech Connect

This workshop focused on novel spectroscopies at Beamlines 11.0.2, 5.3.2 and 9.3.2 at the ALS. The workshop brought together users from a wide range of fields to highlight recent experimental and technical developments both in scanning transmission X-ray spectroscopy (STXM) and ambient pressure photoelectron spectroscopy (APPES). The morning session featured talks on experiments involving new developments at the STXM, while the afternoon session was devoted to those using APXPS. In the morning session, Tolek Tyliszczak discussed the improved detector developments at the STXM, such as an avalanche photodiode detector and fluorescence and electron detection, as well as the continued development of in situ cells for heating, gas flow, and electrochemical cells. Of these, only the avalanche photodiode in combination with a novel multichannel photon-counting system is in routine use in time-resolved studies. Bartel Van Waeyenberge (Ghent University) presented results of magnetic imaging with a time resolution of 70-100 ps combined with a lateral resolution of 20-40 nm performed with the STXM (Beamline 11.0.2). As a complement to the time-domain ''pump-and-probe'' measurements, they developed a frequency-domain ''sine-excitation'' technique in order to study specific eigenmodes of these ferromagnetic patterns with high spatial resolution. This new approach was used to study the gyrotropic vortex motions in micron-sized ferromagnetic patterns. Adam Hitchcock (McMaster University) presented the development, in collaboration with Daniel Guay (INRS, Varennes) and Sherry Zhang, of the apparatus and techniques for applying STXM to in-situ studies of electrochemistry, in particular electrochromism in polyaniline. In addition, substantial progress was reported on a joint project to develop substrates and methods for chemically selective lithography of multilayer polymer systems. Selective patterns, such as that displayed in the figure, can now be written efficiently with the bend magnet STXM on Beamline 5.3.2. Yves Acremann (SSRL) discussed time and spatially resolved X-ray magnetic circular dichroism (XMCD) experiments on spin transfer devices at the STXM (Beamline 11.0.2). These elegant experiments explore time resolved measurements of the magnetization dynamics within a 100 x 150 nm sample influenced by a spin-polarized current. This experiment shows that the magnetization in these magnetic nanostructures are not uniform, as they are influenced by the Oersted field of the charge current needed to generate the spin current. The implementation of a novel multichannel photon counting system in combination with an avalanche photon detector decreased the data-acquisition time by a factor of 10, owing to its ability to resolve the structure of multi bunch mode. Gordon E. Brown, Jr. (Stanford University and SSRL) described ''Applications of STXM to Microbial Bioweathering and Biomineralization''. In the interaction of bacteria with ferrihydrite nanoparticles, microenvironments that were very different than the bulk material were observed, showing that bulk thermodynamics may not be useful for predicting micro phases. Gordon also presented work showing that iron nanoparticles are attracted to the negatively charged bacteria and form a coating that reduces iron oxide minerals. The afternoon session started with presentations by Simon Mun and Hendrik Bluhm, who discussed the current status and the future plans for the two APPES end-stations at the ALS, which are located at Beamlines 9.3.2 and 11.0.2, respectively. In both end-stations, samples can be measured in gaseous environments at pressures of up to several Torr, which makes possible the investigation of numerous phenomena, in particular in the fields of atmospheric and environmental science as well as heterogeneous catalysis. Specific examples of the application of APPES were shown in the following presentations. John Hemminger (University of California, Irvine) reported on APPES investigations at Beamlines 9.3.2 and 11.0.2 of the interaction of alkali halide surfaces with water. The m

Bluhm, Hendrik; Gilles, Mary K.; Mun, Simon B.; Tyliszczak, Tolek

2006-02-01

146

The BioCAT undulator beamline 18ID: a facility for biological non-crystalline diffraction and X-ray absorption spectroscopy at the Advanced Photon Source.  

PubMed

The 18ID undulator beamline of the Biophysics Collaborative Access Team at the Advanced Photon Source, Argonne, IL, USA, is a high-performance instrument designed for, and dedicated to, the study of partially ordered and disordered biological materials using the techniques of small-angle X-ray scattering, fiber diffraction, and X-ray absorption spectroscopy. The beamline and associated instrumentation are described in detail and examples of the representative experimental results are presented. PMID:15310956

Fischetti, R; Stepanov, S; Rosenbaum, G; Barrea, R; Black, E; Gore, D; Heurich, R; Kondrashkina, E; Kropf, A J; Wang, S; Zhang, Ke; Irving, T C; Bunker, G B

2004-08-17

147

A characterization of Kapton polyimide by X-ray photoelectron spectroscopy and energy dispersive spectroscopy  

Microsoft Academic Search

Kapton polyimide films were characterized by X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS). The samples characterized include Kapton-H and Kapton-HN. The XPS data suggest that the Kapton films are mainly poly(4,4'-oxydiphenylene pyromellitimide). The Kapton-HN films were found to have imbedded particles which were identified by EDS to contain calcium and phosphorus. These films also give solid residues of

Pu Sen Wang; T. N. Wittberg; J. Douglas Wolf

1988-01-01

148

NIST data resources for surface analysis by X-ray photoelectron spectroscopy and Auger electron spectroscopy  

Microsoft Academic Search

A description is given of data resources that are available from the National Institute of Standards and Technology (NIST) for X-ray photoelectron spectroscopy (XPS) and Auger-electron spectroscopy. NIST currently has three databases available: an XPS Database, an Electron Elastic-Scattering Cross-Section Database, and an Electron Inelastic-Mean-Free-Path Database. NIST also offers Standard Test Data (STD) for XPS, a set of simulated XPS

C. J. Powell; A. Jablonski; A. Naumkin; A. Kraut-Vass; J. M. Conny; J. R. Rumble

2001-01-01

149

Algorithms for a hand-held miniature x-ray fluorescence analytical instrument  

Microsoft Academic Search

The purpose of this joint program was to provide technical assistance with the development of a Miniature X-ray Fluorescence (XRF) Analytical Instrument. This new XRF instrument is designed to overcome the weaknesses of spectrometers commercially available at the present time. Currently available XRF spectrometers (for a complete list see reference 1) convert spectral information to sample composition using the influence

W. T. Elam; D. Newman; F. Ziemba

1998-01-01

150

Applications of position sensitive germanium detectors for X-ray spectroscopy of highly charged heavy ions  

Microsoft Academic Search

The spectroscopy of atomic transitions in the hard X-ray regime above 15 keV utilizing position-sensitive solid state detectors is discussed. Special emphasis is given to the current detector developments for X-ray spectroscopy of heavy ions at the ESR storage ring where applications for precision spectroscopy as well as for polarization studies are of particular interest. For both cases, the advantages

Th. Stöhlker; D. Banas; H. F Beyer; A. Gumberidze; C. Kozhuharov; E. Kanter; T. Krings; W. Lewoczko; X. Ma; D. Protic; D. Sierpowski; U. Spillmann; S. Tachenov; A. Warczak

2003-01-01

151

EUV and x-ray instrumentation for spectrometry, polarimetry, and imaging in hot plasma diagnostics, atomic physics, and x-ray microscopy: a status report  

NASA Astrophysics Data System (ADS)

The Instrumentation Program at Physics Department of the University of Nevada, Reno, USA is based on results of the development and study of one of first glass capillary optics devices in period from 1974 to earlier 90s in USSR/Russia (by V. Kantsyrev, O. Ananyin, Yu. Bykovsky and collaborators). The main direction of our program is the development of several techniques for extreme ultraviolet, soft x-ray and x-ray optical instrumentation, for spectroscopic diagnostics of hot plasmas, spectroscopic studies of interaction of multicharged ion beams with matter, biomedical x-ray microscopy. Our currently-developed instruments include: EUV polarimeter/spectrometer with GCC polarizing and focusing elements; a high resolution, a high-sensitivity EUV and x-ray spectrometer with focusing GCC, that also serves as a high- transmission window for differential vacuum pumping; a prototype of new multiband, two dimensional EUV and x-ray imaging spectrometer for plasma diagnostics; a pinhole camera with GCC using as a hard x-ray filter; a soft x-ray spectrograph with MLM for plasma diagnostics.

Kantsyrev, Victor L.; Bauer, Bruno S.; Phaneuf, Ronald A.

1998-12-01

152

Ultrafast Conversions Between Hydrogen Bonded Structures in Liquid Water Observed by Femtosecond X-Ray Spectroscopy.  

National Technical Information Service (NTIS)

We present the first femtosecond soft x-ray spectroscopy in liquids, enabling the observation of changes in hydrogen bond structures in water via core-hole excitation. The oxygen K-edge of vibrationally excited water is probed with femtosecond soft x-ray ...

A. M. Lindenberg H. Wen N. Huse R. W. Schoenlein

2010-01-01

153

Examination of passive films on metals with X-ray reflection absorption spectroscopy  

NASA Astrophysics Data System (ADS)

Passive oxide layers on iron, nickel, copper and on their alloys were investigated with X-ray reflection absorption spectroscopy. As specimens, polished bulk metals and thin films on float glass substrates were used. The specimens were electrochemically passivated in alkaline electrolytes at some characteristic potentials and subsequently investigated with X-rays at glancing angles below as well as above the critical angle.

Borthen, P.; Hecht, D.; Abels, J.-M.; Strehblow, H.-H.

1995-02-01

154

Examination of the local structure in composite and lowdimensional semiconductor by X-ray Absorption Spectroscopy  

SciTech Connect

X-ray absorption methods have been successfully used to obtain quantitative information about local atomic composition of two different materials. X-ray Absorption Near Edge Structure analysis and X-Ray Photoelectron Spectroscopy allowed us to determine seven chemical compounds and their concentrations in c-BN composite. Use of Extended X-ray Absorption Fine Structure in combination with Transmission Electron Microscopy enabled us to determine the composition and size of buried Ge quantum dots. It was found that the quantum dots consisted out of pure Ge core covered by 1-2 monolayers of a layer rich in Si.

Lawniczak-Jablonska, K.; Demchenko, I.N.; Piskorska, E.; Wolska,A.; Talik, E.; Zakharov, D.N.; Liliental-Weber, Z.

2006-09-25

155

A whole-system approach to x-ray spectroscopy in cargo inspection systems  

NASA Astrophysics Data System (ADS)

The bremsstrahlung x-ray spectrum used in high-energy, high-intensity x-ray cargo inspection systems is attenuated and modified by the materials in the cargo in a Z-dependent way. Therefore, spectroscopy of the detected x rays yields information about the Z of the x-rayed cargo material. It has previously been shown that such ZSpectroscopy (Z-SPEC) is possible under certain circumstances. A statistical approach, Z-SCAN (Z-determination by Statistical Count-rate ANalysis), has also been shown to be effective, and it can be used either by itself or in conjunction with Z-SPEC when the x-ray count rate is too high for individual x-ray spectroscopy. Both techniques require fast x-ray detectors and fast digitization electronics. It is desirable (and possible) to combine all techniques, including x-ray imaging of the cargo, in a single detector array, to reduce costs, weight, and overall complexity. In this paper, we take a whole-system approach to x-ray spectroscopy in x-ray cargo inspection systems, and show how the various parts interact with one another. Faster detectors and read-out electronics are beneficial for both techniques. A higher duty-factor x-ray source allows lower instantaneous count rates at the same overall x-ray intensity, improving the range of applicability of Z-SPEC in particular. Using an intensity-modulated advanced x-ray source (IMAXS) allows reducing the x-ray count rate for cargoes with higher transmission, and a stacked-detector approach may help material discrimination for the lowest attenuations. Image processing and segmentation allow derivation of results for entire objects, and subtraction of backgrounds. We discuss R&D performed under a number of different programs, showing progress made in each of the interacting subsystems. We discuss results of studies into faster scintillation detectors, including ZnO, BaF2 and PbWO4, as well as suitable photo-detectors, read-out and digitization electronics. We discuss high-duty-factor linear-accelerator x-ray sources and their associated requirements, and how such sources improve spectroscopic techniques. We further discuss how image processing techniques help in correcting for backgrounds and overlapping materials. In sum, we present an integrated picture of how to optimize a cargo inspection system for x-ray spectroscopy.

Langeveld, Willem G. J.; Gozani, Tsahi; Ryge, Peter; Sinha, Shrabani; Shaw, Tim; Strellis, Dan

2013-04-01

156

X-ray chemical analysis of YBa2Cu3Ox thin film by total-reflection-angle X-ray spectroscopy  

Microsoft Academic Search

Scanning electron microscopy and total-reflection-angle X-ray spectroscopy (SEM-TRAXS) was applied to X-ray chemical analysis of a 800 Å thick YBa2Cu3Ox (YBCO) film on an MgO substrate. In this method, the emission efficiency of characeti X-rays, excited by the electron beam of a SEM, from elements composing a thin film is drastically enhanced, as compared to that in the conventional SEM-EDX

Toshio Usui; Masayuki Kamei; Yuji Aoki; Tadataka Morishita; Shoji Tanaka

1992-01-01

157

Structure elucidation of laser dye coumarin-540A by joint application of X-ray diffraction, X-ray fluorescence, prompt fluorescence, UV and visible spectroscopy  

Microsoft Academic Search

X-ray, ultraviolet, and visible light induced photophysical changes of coumarin-540A in ethanol have been studied by the joint applications of X-ray, ultraviolet, and visible spectroscopy. Some impurities were found by X-ray fluorescence measurements. During the high power optical pumping, coumarin showed photochemical changes. Photoproduct emission spectra characteristics showed that photoproduct molecules can also be used as a laser dye at

Sinan S. Keskin; Necdet Aslan; Fuat Bayrakçeken

2007-01-01

158

Structure elucidation of laser-dye coumarin-540A by joint application of X-ray diffraction, X-ray fluorescence, prompt fluorescence, UV and visible spectroscopy  

Microsoft Academic Search

X-ray, ultraviolet, and visible light induced photophysical changes of coumarin-540A in ethanol has been studied by the joint applications of X-ray, ultraviolet, and visible spectroscopy. Some impurities were found by X-ray fluorescence measurements. During the high power optical pumping, coumarin showed photochemical changes. Photoproduct emission spectra characteristics showed that photoproduct molecules could also be used as a laser-dye at a

Sinan S. Keskin; Necdet Aslan; Fuat Bayrakçeken

2007-01-01

159

An instrument for 3D x-ray nano-imaging  

SciTech Connect

We present an instrument dedicated to 3D scanning x-ray microscopy, allowing a sample to be precisely scanned through a beam while the angle of x-ray incidence can be changed. The position of the sample is controlled with respect to the beam-defining optics by laser interferometry. The instrument achieves a position stability better than 10 nm standard deviation. The instrument performance is assessed using scanning x-ray diffraction microscopy and we demonstrate a resolution of 18 nm in 2D imaging of a lithographic test pattern while the beam was defined by a pinhole of 3 {mu}m in diameter. In 3D on a test object of copper interconnects of a microprocessor, a resolution of 53 nm is achieved.

Holler, M.; Raabe, J.; Diaz, A.; Guizar-Sicairos, M.; Quitmann, C.; Menzel, A.; Bunk, O. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

2012-07-15

160

An instrument for 3D x-ray nano-imaging  

NASA Astrophysics Data System (ADS)

We present an instrument dedicated to 3D scanning x-ray microscopy, allowing a sample to be precisely scanned through a beam while the angle of x-ray incidence can be changed. The position of the sample is controlled with respect to the beam-defining optics by laser interferometry. The instrument achieves a position stability better than 10 nm standard deviation. The instrument performance is assessed using scanning x-ray diffraction microscopy and we demonstrate a resolution of 18 nm in 2D imaging of a lithographic test pattern while the beam was defined by a pinhole of 3 ?m in diameter. In 3D on a test object of copper interconnects of a microprocessor, a resolution of 53 nm is achieved.

Holler, M.; Raabe, J.; Diaz, A.; Guizar-Sicairos, M.; Quitmann, C.; Menzel, A.; Bunk, O.

2012-07-01

161

Soft X-ray emission spectroscopy of polycyclic aromatichydrocarbons  

SciTech Connect

High-resolution CK X-ray emission spectra of polycyclicaromatic hydrocarbons (PAH) were measured using synchrotron radiation.The main peak energies in the PAH X-ray spectra shifted to a higherenergy region as the ratio of hydrogenated outer carbon atoms tothenon-hydrogenated inner carbon atoms increased. Discrete variational(DV)-Xa molecular orbital calculations provided theoretical confirmationthat the spectral features depend on the ratio ofhydrogenated/non-hydrogenated carbon atoms, which suggests that thefeatures around the main peaks provide the information of the degree ofhydrogenation in PAH compounds.

Muramatsu, Yasuji; Tomizawa, Kana; Denlinger, Jonathan D.; Perera, Rupert C.C.

2004-04-02

162

New Homogeneous Standards by Atomic Layer Deposition for Synchrotron X-ray Fluorescence and Absorption Spectroscopies.  

SciTech Connect

Quantification of synchrotron XRF analyses is typically done through comparisons with measurements on the NIST SRM 1832/1833 thin film standards. Unfortunately, these standards are inhomogeneous on small scales at the tens of percent level. We are synthesizing new homogeneous multilayer standards using the Atomic Layer Deposition technique and characterizing them using multiple analytical methods, including ellipsometry, Rutherford Back Scattering at Evans Analytical, Synchrotron X-ray Fluorescence (SXRF) at Advanced Photon Source (APS) Beamline 13-ID, Synchrotron X-ray Absorption Spectroscopy (XAS) at Advanced Light Source (ALS) Beamlines 11.0.2 and 5.3.2.1 and by electron microscopy techniques. Our motivation for developing much-needed cross-calibration of synchrotron techniques is borne from coordinated analyses of particles captured in the aerogel of the NASA Stardust Interstellar Dust Collector (SIDC). The Stardust Interstellar Dust Preliminary Examination (ISPE) team have characterized three sub-nanogram, {approx}1{micro}m-sized fragments considered as candidates to be the first contemporary interstellar dust ever collected, based on their chemistries and trajectories. The candidates were analyzed in small wedges of aerogel in which they were extracted from the larger collector, using high sensitivity, high spatial resolution >3 keV synchrotron x-ray fluorescence spectroscopy (SXRF) and <2 keV synchrotron x-ray transmission microscopy (STXM) during Stardust ISPE. The ISPE synchrotron techniques have complementary capabilities. Hard X-ray SXRF is sensitive to sub-fg mass of elements Z {ge} 20 (calcium) and has a spatial resolution as low as 90nm. X-ray Diffraction data were collected simultaneously with SXRF data. Soft X-ray STXM at ALS beamline 11.0.2 can detect fg-mass of most elements, including cosmochemically important oxygen, magnesium, aluminum and silicon, which are invisible to SXRF in this application. ALS beamline 11.0.2 has spatial resolution better than 25 nm. Limiting factors for Stardust STXM analyses were self-imposed limits of photon dose due to radiation damage concerns, and significant attenuation of <1500 eV X-rays by {approx}80{micro}m thick, {approx}25 mg/cm{sup 3} density silica aerogel capture medium. In practice, the ISPE team characterized the major, light elements using STXM (O, Mg, Al, Si) and the heavier minor and trace elements using SXRF. The two data sets overlapped only with minor Fe and Ni ({approx}1% mass abundance), providing few quantitative cross-checks. New improved standards for cross calibration are essential for consortium-based analyses of Stardust interstellar and cometary particles, IDPs. Indeed, they have far reaching application across the whole synchrotron-based analytical community. We have synthesized three ALD multilayers simultaneously on silicon nitride membranes and silicon and characterized them using RBS (on Si), XRF (on Si{sub 3}N{sub 4}) and STXM/XAS (holey Si{sub 3}N{sub 4}). The systems we have started to work with are Al-Zn-Fe and Y-Mg-Er. We have found these ALD multi-layers to be uniform at {micro}m- to nm scales, and have found excellent consistency between four analytical techniques so far. The ALD films can also be used as a standard for e-beam instruments, eg., TEM EELS or EDX. After some early issues with the consistency of coatings to the back-side of the membrane windows, we are confident to be able to show multi-analytical agreement to within 10%. As the precision improves, we can use the new standards to verify or improve the tabulated cross-sections.

Butterworth, A.L.; Becker, N.; Gainsforth, Z.; Lanzirotti, A.; Newville, M.; Proslier, T.; Stodolna, J.; Sutton, S.; Tyliszczak, T.; Westphal, A.J.; Zasadzinski, J. (UCB)

2012-03-13

163

Corrosion and degradation studies utilizing X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

This dissertation involves studies of corrosion behavior at the surface of various metal samples, as well as the degradation of wool fibers obtained from the Star-Spangled Banner. Molybdenum metal and iron-zinc alloys were examined under corrosive conditions, and the degradation of the wool fibers was studied. The behavior of a polished molybdenum metal surface upon exposure to both aerated and deaerated water and 1.0 M NaCl solution was studied by X-ray Photoelectron Spectroscopy (XPS). Exposure to deaerated water and NaCl failed to produce oxidation of the metal surfaces, but exposing the polished metal surface to aerated water produced significant oxidation. Metal surfaces cleaned by argon-ion etching were found to be inert to oxidation by aerated water. The etching process also appears to passivate the metal surface. The behavior of molybdenum metal in 0.5 M Hsb2SOsb4 treated at various potentials has been studied using core and valence band XPS. The study indicates that Mosp{IV} and Mosp{VI} (including possibly Mosp{V} in some cases) were formed as the potential of the system was increased within the active range of molybdenum. The corrosive behavior of iron-zinc alloys that have been electroplated on plain steel in both aerated and deaerated quadruply-distilled water has been studied using XPS. Several different iron-zinc alloys were electroplated for comparative purposes: an iron-rich alloy, a zinc-rich alloy, and an alloy of similar iron and zinc composition. Treatment in aerated water produces oxidation for the iron-rich and similar composition alloys, but the oxide is reduced for the zinc-rich alloy. Degradation of the fibers in the original Star-Spangled Banner has been monitored using XPS and Scanning Electron Microscopy (SEM). Comparison of white and red wool fibers and linen fibers from the flag with new, mechanically-abraded, and chemically-treated white, red, and linen fibers, respectively, was performed in an attempt to determine the fibers' levels of physical and chemical degradation. Chemical treatment of the fibers gives results similar to those for the fibers from the flag, demonstrating that chemical changes to the fiber surface have occurred over time.

Hixson, Holly Gwyndolen

1997-08-01

164

Cosmic X-ray spectroscopy with multilayer optics  

Microsoft Academic Search

Multilayer optics operated at normal incidence offer a powerful new technology for the study of the solar spectrum in the XUV. The spectra of most cosmic X-ray sources are strongly extinguished at wavelengths above 40 A due to absorption and scattering by interstellar grains. We describe a number of configurations which allow multilayer optics to be used at nonnormal angles

Arthur B. C. Walker Jr.; Dennis S. Martinez; Elizabeth S. Paris; Richard B. Hoover; Troy W. Barbee Jr.

1992-01-01

165

Innovations in X-ray-induced electron emission spectroscopy (XIEES)  

SciTech Connect

Currently, a pressing need has arisen for controlling the local atomic and electron structure of materials irrespective of their aggregate state. Efficient approaches to the studies of short-range order are based on phenomena accompanied by interference of secondary electrons excited by primary X-ray radiation. The set of such approaches are commonly referred to as the X-ray absorption fine structure (XAFS) methods. In reality, the XAFS methods are based on the use of synchrotron radiation and applied to structural studies in two modes of measurements, transmission analysis and recording of secondary effects. Only two such effects-specifically, the X-ray fluorescence an d X-ray-induced electron emission effect-are commonly discussed. Access to synchrotron accelerators is problematic for most researchers, so a demand is created for designing laboratory systems that make direct access possible. Since the power of laboratory systems is much lower than that of synchrotrons, it is essential to use much more efficient detectors of secondary electrons. In addition, it is of interest to analyze energy characteristics with a high spatial resolution. Channel multipliers and multichannel boards are incapable of providing such a possibility. For this reason, an improved electron detector has been developed to analyze the photoemission effect in an accelerating field.

Pogrebitsky, K. Ju., E-mail: mischar@mail.ioffe.ru; Sharkov, M. D. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2010-06-15

166

Paraboloidal X-ray telescope mirror for solar coronal spectroscopy  

Microsoft Academic Search

The telescope mirror for the X-ray Spectrograph Spectrometer Telescope System is a sixty degree sector of an extreme off-axis paraboloid of revolution. It was designed to focus a coronal region 1 by 10 arc seconds in size on the entrance slit of the spectrometer after reflection from the gold surface. This paper discusses the design, manufacture, and metrology of the

W. A. Brown; E. C. Bruner Jr.; L. W. Acton; A. Franks; M. Stedman; R. J. Speer

1979-01-01

167

X-ray photoelectron spectroscopy of copper compounds  

Microsoft Academic Search

The X-ray photoelectron spectra of some forty-six copper compounds and complexes have been measured. The chemical shifts obtained from accurate determinations of the binding energies have been qualitatively explained on the basis of the Pauling electronegativity concept using the group electronegatives of Huheey for the polyatomic counter anions. The chemical shifts of the copper atoms as well as the atoms

D. C. Frost; A. Ishitani; C. A. McDowell

1972-01-01

168

Mapping chemical bonding of reaction intermediates with femtosecond X-ray laser spectroscopy  

NASA Astrophysics Data System (ADS)

We determine the pathways in the photo-dissociation reactions of Fe(CO)5 both in the gas phase and in solution by mapping the valence electronic structure of the reaction intermediates with femtosecond X-ray laser spectroscopy.

Wernet, Ph.; Beye, M.; de Groot, F.; Düsterer, S.; Gaffney, K.; Grübel, S.; Hartsock, R.; Hennies, F.; Josefsson, I.; Kennedy, B.; Kunnus, K.; Leitner, T.; Mazza, T.; Meyer, M.; Nordlund, D.; Odelius, M.; Quevedo, W.; Radcliffe, P.; Rajkovic, I.; Schlotter, B.; Scholz, M.; Schreck, S.; Suljoti, E.; Techert, S.; Turner, J.; Weniger, C.; Zhang, W.; Föhlisch, A.

2013-03-01

169

Quantification of Element Abundances of Stardust Interstellar Candidates by Synchrotron Radiation X-Ray Fluorescence Spectroscopy  

NASA Astrophysics Data System (ADS)

Orion and Sirius, two Interstellar Dust Candidates from the NASA Stardust mission were analyzed using hyperspectral fluorescence/diffraction nano-X-ray imaging. Correlation spectroscopy of associated elements helped propose an associated mineralogy.

Simionovici, A. S.; Lemelle, L.; Cloetens, P.; Solé, V. A.; Sans Tresseras, J.-A.; Butterworth, A. L.; Westphal, A. J.; Gainsforth, Z.; Stodolna, J.; Allen, C.; Anderson, D.; Ansari, A.; Bajt, S.; Bassim, N.; Bastien, R. S.; Bechtel, H. A.; Borg, J.; Brenker, F. E.; Bridges, J.; Brownlee, D. E.; Burchell, M.; Burghamme, M.; Changela, H.; Davis, A. M.; Doll, R.; Floss, Ch.; Flynn, G. J.; Frank, D. R.; Grün, E.; Heck, Ph. R.; Hillier, J. K.; Hoppe, P.; Hudson, B.; Huth, J.; Hvide, B.; Kearsley, A.; King, A. J.; Lai, B.; Leitner, J.; Leonard, A.; Leroux, H.; Lettieri, R.; Marchant, W.; Nittler, L. R.; Ogliore, R.; Ja Ong, W. J.; Postberg, F.; Price, M. C.; Sandford, S. A.; Schmitz, S.; Schoonjans, T.; Schreiber, K.; Silversmit, G.; Srama, R.; Stephan, Th.; Sterken, V. J.; Stroud, R. M.; Sutton, S.; Trieloff, M.; Tsou, P.; Tsuchiyama, A.; Tyliszczak, T.; Vekemans, B.; Vincze, L.; Von Korff, J.; Wordsworth, N.; Zevin, D.; Zolensky, M. E.

2013-09-01

170

Electrochemical in-situ reaction cell for X-ray scattering, diffraction and spectroscopy  

SciTech Connect

An electrochemical in-situ reaction cell for hard X-ray experiments with battery electrodes is described. Applications include the small angle scattering, diffraction, and near-edge spectroscopy of lithium manganese oxide electrodes.

Braun, Artur; Granlund, Eric; Cairns, Elton J.

2003-01-27

171

ROSAT PSPC detection of soft X-ray absorption in GB 1428+4217: the most distant matter yet probed with X-ray spectroscopy  

NASA Astrophysics Data System (ADS)

We report on a ROSAT PSPC observation of the highly luminous z=4.72 radio-loud quasar GB 1428+4217 obtained between 1998 December 11 and 17, the final days of the ROSAT satellite. The low-energy sensitivity of the PSPC detector was employed to constrain the intrinsic X-ray absorption of the currently most distant X-ray detected object. Here we present the detection of significant soft X-ray absorption towards GB 1428+4217, making the absorbing material the most distant matter yet probed with X-ray spectroscopy. X-ray variability by 25+/-8per cent is detected on a time-scale of 6500s in the rest frame. The X-ray variation requires an unusually high radiative efficiency ? of at least 4.2, further supporting the blazar nature of the source.

Boller, Th.; Fabian, A. C.; Brandt, W. N.; Freyberg, M. J.

2000-06-01

172

Characterization of arsenic in lake sediments by X-ray photoelectron spectroscopy  

SciTech Connect

Arsenic in the sediments of Lake Usori (Usori-ko or Osoresan-ko) and Lake Mashu (Mashu-ko) has been characterized by X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger electron spectroscopy and shown to exist as sulfide and arsenite, respectively. In the Lake Mashu sediment, surface concentration of As determined by XPS was significantly higher than the average concentration.

Soma, Mitsuyuki; Tanaka, Atsushi; Seyama, Haruhiko; Satake, Kenichi (National Institute for Environmental Studies, Ibaraki (Japan))

1994-06-01

173

The Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS)  

NASA Astrophysics Data System (ADS)

The Linac Coherent Light Source (LCLS) became the first ever operational hard x-ray free-electron laser in 2009. It will operate as a user facility capable of delivering unique research opportunities in multiple fields of science. The LCLS and the LCLS Ultrafast Science Instruments (LUSI) construction projects are developing instruments designed to make full use of the capabilities afforded by the LCLS beam. One such instrument is being designed to utilize the LCLS coherent beam to image with high resolution any sub-micron object. This instrument is called the Coherent X-ray Imaging (CXI) instrument. This instrument will provide a flexible optical system capable of tailoring key beam parameters for the users. A suite of shot-to-shot diagnostics will also be provided to characterize the beam on every pulse. The provided instrumentation will include multi-purpose sample environments, sample delivery and a custom detector capable of collecting two-dimensional (2D) data at 120 Hz. In this paper, the LCLS will be briefly introduced, as well as the technique of coherent x-ray diffractive imaging (CXDI). A few examples of scientific opportunities arising from use of the CXI instrument will be described. Finally, the conceptual layout of the instrument will be presented, together with a description of the key requirements for the overall system and of specific devices required.

Boutet, Sébastien; Williams, Garth J.

2010-03-01

174

The Coherent X-ray Imaging (CXI) Instrument at the Linac Coherent Light Source (LCLS)  

SciTech Connect

The Linac Coherent Light Source (LCLS) has become the first ever operational hard X-ray Free Electron Laser in 2009. It will operate as a user facility capable of delivering unique research opportunities in multiple fields of science. The LCLS and the LCLS Ultrafast Science Instruments (LUSI) construction projects are developing instruments designed to make full use of the capabilities afforded by the LCLS beam. One such instrument is being designed to utilize the LCLS coherent beam to image with high resolution any sub-micron object. This instrument is called the Coherent X-ray Imaging (CXI) instrument. This instrument will provide a flexible optical system capable of tailoring key beam parameters for the users. A suite of shot-to-shot diagnostics will also be provided to characterize the beam on every pulse. The provided instrumentation will include multi-purpose sample environments, sample delivery and a custom detector capable of collecting 2D data at 120 Hz. In this article, the LCLS will be briefly introduced along with the technique of Coherent X-ray Diffractive Imaging (CXDI). A few examples of scientific opportunities using the CXI instrument will be described. Finally, the conceptual layout of the instrument will be presented along with a description of the key requirements for the overall system and specific devices required.

Boutet, Sebastien

2011-08-16

175

AEGIS: An Astrophysics Experiment for Grating and Imaging Spectroscopy---a Soft X-ray, High-resolution Spectrometer  

NASA Astrophysics Data System (ADS)

AEGIS is a concept for a high-resolution soft X-ray spectroscopic observatory developed in response to NASA's request for definitions of the next X-ray astronomy mission. At a small fraction of the cost of the once-planned International X-ray Observatory (IXO), AEGIS has capabilities that surpass IXO grating spectrometer requirements, and which are far superior to those of existing soft X-ray spectrometers. AEGIS incorporates innovative technology in X-ray optics, diffraction gratings and detectors. The mirror uses high area-to-mass ratio segmented glass architecture developed for IXO, but with smaller aperture and larger graze angles optimized for high-throughput grating spectroscopy with low mass and cost. The unique Critical Angle Transmission gratings combine low mass and relaxed figure and alignment tolerances of Chandra transmission gratings but with high diffraction efficiency and resolving power of blazed reflection gratings. With more than an order of magnitude better performance over Chandra and XMM grating spectrometers, AEGIS can obtain high quality spectra of bright AGN in a few hours rather than 10 days. Such high resolving power allows detailed kinematic studies of galactic outflows, hot gas in galactic haloes, and stellar accretion flows. Absorption line spectroscopy will be used to study large scale structure, cosmic feedback, and growth of black holes in thousands of sources to great distances. AEGIS will enable powerful multi-wavelength investigations, for example with Hubble/COS in the UV to characterize the intergalactic medium. AEGIS will be the first observatory with sufficient resolution below 1 keV to resolve thermally-broadened lines in hot ( 10 MK) plasmas. Here we describe key science investigations enable by Aegis, its scientific payload and mission plan. Acknowledgements: Support was provided in part by: NASA SAO contract SV3-73016 to MIT for the Chandra X-ray Center and Science Instruments; NASA grant NNX08AI62G; and the MKI Instrumentation Development Fund.

Huenemoerder, David; Bautz, M. W.; Davis, J. E.; Heilmann, R. K.; Houck, J. C.; Marshall, H. L.; Neilsen, J.; Nicastro, F.; Nowak, M. A.; Schattenburg, M. L.; Schulz, N. S.; Smith, R. K.; Wolk, S.; AEGIS Team

2012-01-01

176

InFOCµS: A Balloon Instrument with <10 Arc Second Hard X-ray Imaging  

NASA Astrophysics Data System (ADS)

The International Focusing Optics Collaboration for µCrab Sensitivity (InFOCµS) is currently funded to develop a balloon payload with a multilayer hard X-ray telescope based on slumped glass technology similar to NuSTAR, but with spatial resolution 40 times smaller PSF area than NuSTAR). The key science goal for this technology is a deep hard X-ray survey to understand role of AGN/black holes in the formation of galaxies. Due to obscuration, this can only be achieved in the hard X-ray band, where absorption is insignificant, and that only hard X-ray measurements can unambiguously determine the luminosities of individual AGN. InFOCµS will demonstrate the technology necessary to resolve the cosmic hard X-ray background and bridge the gap between NuSTAR, which can only resolve 45-65% of the background due to source confusion, and Chandra, which can detect all of the absorbed sources only at z>2. A hard X-ray survey with high spatial resolution would be a direct measurement of the luminosity function of AGN near the peak of their activity at z=0.8. We will present our approach to achieve high spatial resolution hard X-ray imaging at a cost that can be demonstrated in a balloon instrument with a resolved image of the Crab Nebula, and can be scaled to a deep-survey Explorer mission. This requires extensive refinement of the glass mirror technology at small increase in cost, higher spatial resolution focal plane detectors, and the use of techniques to achieve the extremely low background necessary for very long integration times required for a deep survey. The balloon payload will require significant improvements in pointing stability and knowledge over previous high-energy instruments to utilize the imaging capability of this telescope. InFOCµS is being prepared for a flight in the fall of 2013.

Tueller, Jack; Zhang, W.; Barthelmy, S. D.; Furuzawa, A.; Haba, Y.; Krimm, H.; Kunieda, H.; Okajima, T.; Miyazawa, T.; Mushotzky, R. F.; Tamura, K.; Tawara, Y.

2012-01-01

177

High resolution X-ray spectroscopy with superconducting tunnel junctions  

NASA Astrophysics Data System (ADS)

We are developing detectors based on superconducting tunnel junctions which will provide position sensitive detectors with much better energy resolution than current state of the art CCD cameras. The amount of energy required to create a charge carrier in a superconductor is about three orders of magnitude smaller than in standard semiconductor detectors. The drawback of the necessarily small size of superconducting tunnel junctions has been compensated by a separation of X-ray absorber and detecting tunnel junction ('quasiparticle trapping'). We report on results with our detector which can resolve the 5.89 keV manganese line with an energy resolution of better than 60 eV. In addition, position resolution better than 5 microns has been demonstrated with an absorber 470 microns long. To match the detector to the spot size of the X-ray optics in use, a multielement detector is under development.

Kraus, H.; Jochum, J.; Kemmather, B.; Gutsche, M.

1992-10-01

178

Fundamental studies of X-ray and secondary electron spectroscopy  

Microsoft Academic Search

Microanalysis of submicron particles in the Scanning Electron Microscope (SEM) is only possible by using low incident electron beam energies due to smaller interaction volume and suppressed beam induced charging. Such low beam energies must use L- and M-lines rather than the familiar K-lines. The information about the fundamental parameters of X-ray emission and transport at low energies is limited,

Satya Prasad Mulapudi

2004-01-01

179

Measuring Black Hole Spin Using X-Ray Reflection Spectroscopy  

NASA Astrophysics Data System (ADS)

I review the current status of X-ray reflection (a.k.a. broad iron line) based black hole spin measurements. This is a powerful technique that allows us to measure robust black hole spins across the mass range, from the stellar-mass black holes in X-ray binaries to the supermassive black holes in active galactic nuclei. After describing the basic assumptions of this approach, I lay out the detailed methodology focusing on "best practices" that have been found necessary to obtain robust results. Reflecting my own biases, this review is slanted towards a discussion of supermassive black hole (SMBH) spin in active galactic nuclei (AGN). Pulling together all of the available XMM-Newton and Suzaku results from the literature that satisfy objective quality control criteria, it is clear that a large fraction of SMBHs are rapidly-spinning, although there are tentative hints of a more slowly spinning population at high (M>5×107 M ?) and low (M<2×106 M ?) mass. I also engage in a brief review of the spins of stellar-mass black holes in X-ray binaries. In general, reflection-based and continuum-fitting based spin measures are in agreement, although there remain two objects (GRO J1655-40 and 4U 1543-475) for which that is not true. I end this review by discussing the exciting frontier of relativistic reverberation, particularly the discovery of broad iron line reverberation in XMM-Newton data for the Seyfert galaxies NGC 4151, NGC 7314 and MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk reflection, this detection of reverberation demonstrates that future large-area X-ray observatories such as LOFT will make tremendous progress in studies of strong gravity using relativistic reverberation in AGN.

Reynolds, Christopher S.

2013-08-01

180

Measuring instrument for X-ray structure determinations of liquid or amorphous materials  

Microsoft Academic Search

The present invention relates to an instrument for measuring the variations in intensity of a beam of X-rays scattered by liquid or amorphous solid materials, which comprises: a goniometric head carrying said material and mounted rotationally movable, a position sensitive proportional detector mounted movable along a radial supporting arm, with a rotational motion which is coaxial to the motion of

J. Galy; P. Lecante; A. Mosset

1984-01-01

181

Broad-band soft x-ray diagnostic instruments at the LLNL Novette laser facility  

SciTech Connect

Complementary broad-band instruments have been developed to measure time dependent, absolute soft x-ray spectra at the Lawrence Livermore National Laboratory (LLNL) Nd glass laser irradiation facilities. Absolute flux measurements of x rays emitted from laser-produced plasmas are important for understanding laser absorption and energy transport. We will describe two new 10-channel XRD systems that have been installed at the LLNL Novette facility for use in the 0.15- to 1.5-keV range. Since XRD channel time response is limited by available oscilloscope performance to 120 ps, a soft x-ray streak camera has been developed for better time resolution (20 ps) and greater dynamic range (approx.10/sup 3/) in the same x-ray energy region. Using suitable filters, grazing incidence mirrors, and a gold or cesium-iodide transmission cathode, this streak camera instrument has been installed at Novette to provide one broad and four relatively narrow channels. It can also be used in a single channel, spatially discriminating mode by means of pinhole imaging. The complementary nature of these instruments has been enhanced by locating them in close proximity and matching their channel energy responses. As an example of the use of these instruments, we present results from Novette 2..omega..(0.53 ..mu..m) gold disk irradiations at 1 ns and 10/sup 14/ to 10/sup 15/ W/cm/sup 2/.

Tirsell, K.G.; Lee, P.H.Y.; Nilson, D.G.; Medecki, H.

1983-09-15

182

In Situ Small Angle X-ray Scattering, Wide Angle X-ray Scattering, and Raman Spectroscopy of Microwave Synthesis  

SciTech Connect

Recent studies in microwave chemistry have proven many enhancements in reaction rates and selectivities. Most dramatic are several zeolite syntheses where over an order of magnitude more rapid rates are often, but not always, found. The reasons for these enhancements are not understood in part because in situ spectroscopies under microwave exposure are problematic. Thus, techniques have been slow to develop. This study describes a novel system with which x-ray scattering and Raman studies can be performed in situ during exposure to microwave radiation. The mechanisms and rates for the syntheses of zeolites or other microwave syntheses can be studied dynamically in this manner. A 2.45 GHz waveguide system operating in single pass or as a tuned cavity was developed through which an x-ray beam and/or a Raman laser could probe a synthesis solution and the appropriate scattering are studied. The X10A beamline at Brookhaven National Synchrotron Light Source was used for these studies.

Tompsett,G.; Panzarella, B.; Conner, W.; Yngvesson, K.; Lu, F.; Suib, S.; Jones, K.; Bennett, S.

2006-01-01

183

Atomic physics studies of highly charged ions on tokamaks using x-ray spectroscopy  

SciTech Connect

An overview is given of atomic physics issues which have been studied on tokamaks with the help resolution x-ray spectroscopy. The issues include the testing of model calculations predicting the excitation of line radiation, the determination of rate coefficients, and accurate atomic structure measurements. Recent research has focussed primarily on highly charged heliumlike (22 less than or equal to Z less than or equal to 28) and neonlike (34 less than or equal to Z less than or equal to 63) ions, and results are presented from measurements on the PLT and TFTR tokamaks. Many of the measurements have been aided by improved instrumental design and new measuring techniques. Remarkable agreement has been found between measurements and theory in most cases. However, in this review those areas are stressed where agreement is worst and where further investigations are needed. 19 refs., 13 figs., 2 tabs.

Beiersdorfer, P.; von Goeler, S.; Bitter, M.; Hill, K.W.

1989-07-01

184

Microreactor Cells for High-Throughput X-ray Absorption Spectroscopy  

SciTech Connect

High-throughput experimentation has been applied to X-ray Absorption spectroscopy as a novel route for increasing research productivity in the catalysis community. Suitable instrumentation has been developed for the rapid determination of the local structure in the metal component of precursors for supported catalysts. An automated analytical workflow was implemented that is much faster than traditional individual spectrum analysis. It allows the generation of structural data in quasi-real time. We describe initial results obtained from the automated high throughput (HT) data reduction and analysis of a sample library implemented through the 96 well-plate industrial standard. The results show that a fully automated HT-XAS technology based on existing industry standards is feasible and useful for the rapid elucidation of geometric and electronic structure of materials.

Beesley, Angela; Tsapatsaris, Nikolaos; Weiher, Norbert [School of Chemical Engineering and Analytical Science, University of Manchester, Sackville Street, P.O. Box 88. Manchester, M60 1QD (United Kingdom); Tromp, Moniek; Evans, John [School of Chemistry, University of Southhampton, Highfield, Southampton, SO17 1BJ (United Kingdom); Dent, Andy [Diamond Light Source Ltd., Diamond House, Chilton, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Harvey, Ian [Synchrotron Radiation Source (SRS), Daresbury Laboratory, Warrington, Cheshire, WA4 4AD (United Kingdom); Schroeder, Sven L. M. [School of Chemical Engineering and Analytical Science, University of Manchester, Sackville Street, P.O. Box 88. Manchester, M60 1QD (United Kingdom); School of Chemistry, University of Manchester, Sackville Street, P.O. Box 88. Manchester, M60 1QD (United Kingdom)

2007-01-19

185

Issues concerning solid state detectors for EXAFS. [X-ray Absorption Fine Structure Spectroscopy  

SciTech Connect

Fluorescence extended x-ray absorption fine structure spectroscopy (EXAFS) is a commonly used technique in conjunction with x-ray synchrotron radiation for studying the local atomic structure of dilute elements in biological, geological and materials systems. Due to the nature of the EXAFS technique, and the difficulties associated with the detection of low energy x-rays, EXAFS has been used primarily in the energy range above 5 keV. However, there are a number of elements of interest with K- or L-absorption edges below 5 keV, which have not been easily accessible with existing EXAFS instrumentation. Several characteristics of solid state detectors must be optimized for use in low energy EXAFS measurements. The detector entrance window, or dead layer,'' must be as thin as possible to minimize the attenuation of the fluorescent signal. The detector spectral backgrounds must be minimized so that the tailing background on the low energy side of the scattered photopeak is as low as possible to maximize the S/N of the fluorescent photopeak. Based on our work, a thin Pd surface barrier contact on a Si(Li) detector offers the thinnest detector dead layer and also the lowest spectral background for the Si(Li) and Ge detectors studied to date. To maximize the S/N, the detectors must be operated at as high a count rate as possible, without compromising detector energy resolution. High count rates can be achieved using multiple detector arrays; close packing of the detector elements can further increase the S/N by utilizing the best'' portion of the scattered polarized synchrotron beam.

Rossington, C.S.; Giauque, R.D.; Jaklevic, J.M.

1991-10-01

186

High-Resolution Soft X-ray Spectroscopy of a Gamma-ray Burst X-ray Afterglow  

Microsoft Academic Search

We propose a deep TOO observation of a bright X-ray afterglow of a gamma-ray burst using the Chandra LETG\\/ACIS-S. The trigger will be based primarily on the amount of X-ray variability observed during it's early afterglow phases, which will be monitored with the X-ray Telescope onboard the Swift satellite. Additional constraints including X-ray flux and line-of-sight Galactic column density will

Masao Sako

2003-01-01

187

High-Resolution Soft X-ray Spectroscopy of a Gamma-ray Burst X-ray Afterglow  

Microsoft Academic Search

We propose a deep TOO observation of a bright X-ray afterglow of a gamma-ray burst using the Chandra LETG\\/ACIS-S. The trigger will be based primarily on the amount of X-ray variability observed during it's early afterglow phases, which will be monitored with the X-ray Telescope onboard the Swift satellite. Additional constraints including X-ray flux and line-of-sight Galactic column density will

Masao Sako

2004-01-01

188

X-ray imaging crystal spectroscopy for use in plasma transport research.  

PubMed

This research describes advancements in the spectral analysis and error propagation techniques associated with x-ray imaging crystal spectroscopy (XICS) that have enabled this diagnostic to be used to accurately constrain particle, momentum, and heat transport studies in a tokamak for the first time. Doppler tomography techniques have been extended to include propagation of statistical uncertainty due to photon noise, the effect of non-uniform instrumental broadening as well as flux surface variations in impurity density. These methods have been deployed as a suite of modeling and analysis tools, written in interactive data language (IDL) and designed for general use on tokamaks. Its application to the Alcator C-Mod XICS is discussed, along with novel spectral and spatial calibration techniques. Example ion temperature and radial electric field profiles from recent I-mode plasmas are shown, and the impact of poloidally asymmetric impurity density and natural line broadening is discussed in the context of the planned ITER x-ray crystal spectrometer. PMID:23206059

Reinke, M L; Podpaly, Y A; Bitter, M; Hutchinson, I H; Rice, J E; Delgado-Aparicio, L; Gao, C; Greenwald, M; Hill, K; Howard, N T; Hubbard, A; Hughes, J W; Pablant, N; White, A E; Wolfe, S M

2012-11-01

189

Chandra X-ray Observatory high-resolution x-ray spectroscopy of stars: Modeling and interpretation  

Microsoft Academic Search

The Chandra X-ray Observatory grating spectrometers allow study of stellar spectra at resolutions on the order of 1000. Prior x-ray observatories’ low resolution data have shown that nearly all classes of stars emit x rays. Chandra reveals details of line and continuum contributions to the spectra which can be interpreted through application of plasma models based on atomic databases. For

David P. Huenemoerder

2004-01-01

190

Chandra X-ray Observatory high-resolution x-ray spectroscopy of stars: Modeling and interpretation  

Microsoft Academic Search

The Chandra X-ray Observatory grating spectrometers allow study of stellar spectra at resolutions on the order of 1000. Prior x-ray observatories' low resolution data have shown that nearly all classes of stars emit x rays. Chandra reveals details of line and continuum contributions to the spectra which can be interpreted through application of plasma models based on atomic databases. For

David P. Huenemoerder

2004-01-01

191

Two-color phase-sensitive x-ray pump-probe spectroscopy  

SciTech Connect

X-ray pump-probe spectroscopy is studied theoretically. It is shown that two-color--optical+x-ray--excitation with constant phase of the pump radiation exhibits strong interference between the one- and two-photon excitation channels. This effect is found to be large for both long and short pump pulses, while the interference vanishes for x-ray pulses longer than one cycle of the pump field. It is predicted that the spectral shape of x-ray absorption is strongly influenced by the absolute phase of the pump light. A strong sensitivity of the x-ray absorption and/or photoionization profile to the phase and detuning of the pump field is predicted, as well as to the duration of the x-ray pulse. Our simulations display oscillations of x-ray absorption as a function of the delay time. This effect allows the synchronization of the x-ray pulse relative to the ''comb'' of the pump radiation. The interference pattern copies the temporal and space distribution of the pump field. We pay special attention to the role of molecular orientation for the interference effect.

Guimaraes, F.F. [Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden); Departamento de Quimica, Universidade Federal de Minas Gerais, Avenida Antonio Carlos, 6627, CEP-31270-901, Belo Horizonte, Minais Gerais (Brazil); Kimberg, V.; Gel'mukhanov, F.; Aagren, H. [Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden)

2004-12-01

192

Prototyping a global soft X-ray imaging instrument for heliophysics, planetary science, and astrophysics science  

NASA Astrophysics Data System (ADS)

We describe current progress in the development of a prototype wide field-of-view soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The prototype will provide proof-of-concept for a future flight instrument capable of imaging the entire dayside magnetosheath from outside the magnetosphere. Such an instrument was proposed for the ESA AXIOM mission.

Collier, M. R.; Porter, F. S.; Sibeck, D. G.; Carter, J. A.; Chiao, M. P.; Chornay, D. J.; Cravens, T.; Galeazzi, M.; Keller, J. W.; Koutroumpa, D.; Kuntz, K.; Read, A. M.; Robertson, I. P.; Sembay, S.; Snowden, S.; Thomas, N.

2012-04-01

193

Measuring redshifts using X-ray spectroscopy of galaxy clusters: results from Chandra data and future prospects  

NASA Astrophysics Data System (ADS)

Context. The ubiquitous presence of the Fe line complex in the X-ray spectra of galaxy clusters offers the possibility of measuring their redshift without resorting to spectroscopic follow-up observations. In practice, the blind search of the Fe line in X-ray spectra is a difficult task and is affected not only by limited S/N (particularly at high redshift), but also by several systematic errors, associated with varying Fe abundance values, ICM temperature gradients, and instrumental characteristics. Aims: We assess the accuracy with which the redshift of galaxy clusters can be recovered from an X-ray spectral analysis of Chandra archival data. We present a strategy to compile large surveys of clusters whose identification and redshift measurement are both based on X-ray data alone. Methods: We apply a blind search for K-shell and L-shell Fe line complexes in X-ray cluster spectra using Chandra archival observations of galaxy clusters. The Fe line can be detected in the ICM spectra by simply analyzing the C-statistics variation ?Cstat as a function of the redshift parameter, when all the other model parameters are frozen to the best-fit values. We repeat the measurement under different conditions, and compare the X-ray derived redshift zX with the one obtained by means of optical spectroscopy zo. We explore how a number of priors on metallicity and luminosity can be effectively used to reduce catastrophic errors. The ?Cstat provides the most effective means of discarding wrong redshift measurements and estimating the actual error in zX. Results: We identify a simple and efficient procedure for optimally measuring the redshifts from the X-ray spectral analysis of clusters of galaxies. When this procedure is applied to mock catalogs extracted from high sensitivity, wide-area cluster surveys, such as those proposed with Wide Field X-ray Telescope (WFXT) mission, it is possible to obtain complete samples of X-ray clusters with reliable redshift measurements, thus avoiding time-consuming optical spectroscopic observations. Our analysis shows that, in the case of WFXT, a blind Fe line search is 95% successful for spectra with more than 1000 net counts, whenever ?Cstat > 9, corresponding formally to a 3? confidence level. The average error in the redshift zX decreases rapidly for higher values of ?Cstat. Finally, we discuss how to estimate the completeness of a large cluster samples with measured zX. This methodology will make it possible to trace cosmic growth by studying the evolution of the cluster mass function directly using X-ray data.

Yu, H.; Tozzi, P.; Borgani, S.; Rosati, P.; Zhu, Z.-H.

2011-05-01

194

Superconductive tunnel junctions for X-ray spectroscopy  

NASA Astrophysics Data System (ADS)

Superconductive tunnel junctions are under development as detectors for X-ray astronomy in the 0.5 - 10 keV energy range, because of their potentially high energy resolution in combination with high detection efficiency. Absorber-junction combinations offer the prospect of high energy resolution detectors with a high detection efficiency and a reasonable (about 1/sq cm) size. The proximity effect between the Nb absorber and the Al trapping layer plays a dominant role. A study of the proximity effect in Nb/Al/Al2O3/Al/Nb junctions with different Al-layer, the trapping layer, thicknesses is presented.

de Korte, P. A. J.; van den Berg, M. L.; Bruijn, M. P.; Frericks, M.; Le Grand, J. B.; Gijsbertsen, J. G.; Houwman, E. P.; Flokstra, J.

1992-10-01

195

EUV Spectroscopy of High-redshift X-ray Objects  

Microsoft Academic Search

As astronomical observations are pushed to cosmological distances (z>3) the spectral energy distributions of X-ray objects, AGNs for example, will have their maxima redshifted into the EUV waveband ( 90-912 Å\\/0.1-0.01 keV). Consequently, a wealth of spectral diagnostics, provided by, for example, the Fe L-shell complex ( 60-6 Å\\/0.2-2.0 keV) and the O VII\\/VIII lines ( 20 Å\\/0.5 keV), will

Michael Paul Kowalski; M. T. Wolff; K. S. Wood; T. W. Barbee Jr.

2010-01-01

196

X-Ray Diffraction Instrument For In Situ Analysis of Martian Rocks  

NASA Astrophysics Data System (ADS)

The chemistry measured by XRF and APX during previous mission to Mars yielded rich information on certain aspects of Martian materials but cannot constrain the exact mineral assemblages and as a result, neither the genesis of the rocks or soils. For example, in some cases, a volcanic rock, a sedimentary rock, and a metamorphic rock can have the same chemical composition. Therefore in order to assess the Martian environment in which the rock or soil was produced, we need to perform analysis of the mineralogy of the material. For this purpose, we propose an X-Ray Instrument for Mineralogical Analysis of Planetary surface materials (XMAP) for Mars 2005 mission. Basically, XMAP will consist of an X-ray source, a sample holder and a CCD detector. The diffraction technique is based on the capability of atom lattices to diffract incident X-ray beams. The diffracted X-rays interfere each other and only the beams that interfere positively can reach the detector. The instrument may be also thought to be arranged for both a lander or a rover configuration with a few minor adaptive changes. XMAP will perform a no destructive analysis and a preparation of the sample is not required. We are planning to be able to discriminate a high range of minerals from clay or phyllosilicates, characterised by high interplanar lattice distance, to oxides and carbonates or evaporites. This rock spectrum is what we expect for exobiological exploration of Mars 2005 landing site. In addition, with XRD it is possible to identify the presence of water ice or dioxide ice; in fact, they give a different characteristic peak in the diffractometer spectrum. The same X-Ray source and detector for diffractometry analysis can be used for X-ray fluorescence combining the two methods and giving an accurate petrologic characterisation of rock sample.

Marinangeli, L.; Baliva, A.; Piluso, E.; Ori, G. G.; Casanova, I.; Lenti, A.; Ponzoni, C.; Cavazzutti, E.; Isabella, L.

1999-09-01

197

Atomic structure of nickel phthalocyanine probed by X-ray absorption spectroscopy and density functional simulations  

NASA Astrophysics Data System (ADS)

The local atomic structure of Ni in nickel phthalocyanine was studied by K-edge X-ray absorption fine structure spectroscopy. The obtained inter atomic nickel-nitrogen distance differs from the reference X-ray diffraction data so an additional study was performed within density functional theory framework. The justification of the used theoretical approach was provided by a comparison of theoretical free electron densities of states with experimental Ni K-edge X-ray absorption near edge spectra. The refined Ni local environment retain the reference structure of the molecule except for the length of Ni-N bond which increases to 1.90 Å.

Avakyan, L. A.; Manukyan, A. S.; Mirzakhanyan, A. A.; Sharoyan, E. G.; Zubavichus, Y. V.; Trigub, A. L.; Kolpacheva, N. A.; Bugaev, L. A.

2013-03-01

198

Characterization of CuHal-intercalated carbon nanotubes with x-ray absorption spectroscopy combined with x-ray photoelectron and resonant photoemission spectroscopies  

NASA Astrophysics Data System (ADS)

Encapsulated single-walled carbon nanotubes (SWCNTs) with inner channels filled by different compounds present the new class of composite materials. Such CNTs give opportunity to form 1D nanocrystals as well as quantum nanowires with new physical and chemical properties inside the tubes. The present study is aimed to characterize the possible chemical interaction between CuHal (Hal=I, Cl, Br) and SWCNTs in CuHal@SWCNTs and electronic structure of the latter using high-resolution near edge X-ray absorption fine structure (NEXAFS) spectroscopy combined with high-resolution X-ray photoelectron spectroscopy and resonant photoemission spectroscopy. The present study has shown that there is a chemical interaction between the filler and ?-electron subsystem of CNTs which is accompanied by changes of the atomic and electronic structure of the filler during the encapsulating it inside CNTs.

Brzhezinskaya, M.; Generalov, A.; Vinogdradov, A.; Eliseev, A.

2013-04-01

199

X-ray spectroscopy of GRO J1655-40  

NASA Astrophysics Data System (ADS)

After seven years in quiescence, GRO J1655-40 started a new outburst in February 2005, rising to a high/soft state in March 2005. We report here the results of four XMM-Newton observations performed on 27 February 2005 in the low/hard state, and on three consecutive days in March 2005 during the rise of the source to its high/soft state. The X-ray spectrum of GRO J1655-40 was dominated in the high/soft state by the thermal emission from the accretion disk, with a maximum temperature of 1.3 keV. We detected two absorption lines in the EPIC-pn spectra at 6.7-6.8 and 7.8-8.0 keV, which could be identified as the K? and K? lines of either blended Fe XXV and Fe XXVI or blueshifted Fe XXV. We found no orbital dependence on the X-ray properties, which provides an upper limit for the inclination of the system of 73 ° .

Sala, Gloria; Greiner, J.; Vink, J.; Haberl, F.

200

Watching energy transfer in metalloporphyrin heterodimers using stimulated X-ray Raman spectroscopy.  

PubMed

Understanding the excitation energy transfer mechanism in multiporphyrin arrays is key for designing artificial light-harvesting devices and other molecular electronics applications. Simulations of the stimulated X-ray Raman spectroscopy signals of a Zn/Ni porphyrin heterodimer induced by attosecond X-ray pulses show that these signals can directly reveal electron-hole pair motions. These dynamics are visualized by a natural orbital decomposition of the valence electron wavepackets. PMID:24019462

Biggs, Jason D; Zhang, Yu; Healion, Daniel; Mukamel, Shaul

2013-09-09

201

Probing surface states of Cu\\/Ni thin films using x-ray absorption spectroscopy  

Microsoft Academic Search

Surface and interface properties of Cu thin films (1-4 monolayers) deposited on Ni(100) have been extracted by means of x-ray absorption spectroscopy and analyzed in combination with ab initio density-functional calculations. An unoccupied Cu surface state is identified in an x-ray absorption spectra and studied as a function of film thickness. Experimental data is supported by calculations of the layer-resolved

O. Karis; M. Magnuson; T. Wiell; M. Weinelt; N. Wassdahl; A. Nilsson; N. Mårtensson; E. Holmström; A. M. Niklasson; O. Eriksson; B. Johansson

2001-01-01

202

X-ray Spectroscopy of Hot Dense Plasmas: Experimental Limits, Line Shifts and Field Effects  

SciTech Connect

High-resolution x-ray spectroscopy is capable of providing complex information on environmental conditions in hot dense plasmas. Benefiting from application of modern spectroscopic methods, we report experiments aiming at identification of different phenomena occurring in laser-produced plasma. Fine features observed in broadened profiles of the emitted x-ray lines and their satellites are interpreted using theoretical models predicting spectra modification under diverse experimental situations.

Renner, Oldrich [Institute of Physics, Academy of Sciences CR, Na Slovance 2, 18221 Prague (Czech Republic); Sauvan, Patrick [Dept. de Ingenieria Energetica-UNED, 28040 Madrid (Spain); Dalimier, Elisabeth; Riconda, Caterina; Rosmej, Frank B. [Physique Atomique dans les Plasmas Denses, LULI, UMR 7605, CNRS-CEA-Ecole Polytechnique- Universite Paris 6, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Weber, Stefan [Physique Atomique dans les Plasmas Denses, LULI, UMR 7605, CNRS-CEA-Ecole Polytechnique- Universite Paris 6, 4 Place Jussieu, 75252 Paris Cedex 05 (France); CELIA Universite Bordeaux-CEA, 33405 Talence (France); Nicolai, Philippe; Peyrusse, Olivier [CELIA Universite Bordeaux-CEA, 33405 Talence (France); Uschmann, Ingo; Hoefer, Sebastian; Kaempfer, Tino; Loetzsch, Robert; Zastrau, Ulf; Foerster, Eckhart [Institut fuer Optik und Quantenelektronik, Friedrich-Schiller-Universitaet, 07743 Jena (Germany); Oks, Eugene [Physics Department, 206 Allison Laboratory, Auburn University, Auburn, AL 36849 (United States)

2008-10-22

203

X-ray-absorption spectroscopy on strontium titanate under high pressure  

Microsoft Academic Search

The pressure dependence of the interatomic distances and their mean-square deviations (Debye-Waller factors) in SrTiO3 are studied by x-ray-absorption spectroscopy in a diamond anvil cell up to 15 GPa. The pressure dependence of Sr-O and Sr-Ti interatomic distances have been determined and compared with x-ray-diffraction data. The comparison confirms the occurrence of a structural phase transition induced by pressure. In

M. Fischer; B. Bonello; J. P. Itié; A. Polian; E. Dartyge; A. Fontaine; H. Tolentino

1990-01-01

204

X-ray absorption spectroscopy: A fluorescence detection system based on a plastic scintillator  

Microsoft Academic Search

A fluorescence detection system based on a plastic scintillator is presented that can be used for both X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Its counting rate is limited by the pulsation frequency of the synchrotron radiation (3.16×106 counts s-1), and can be theoretically extended to roughly 5×107 counts s-1 if used on a multibunch

G. Tourillon; D. Guay; M. Lemonnier; F. Bartol; M. Badeyan

1990-01-01

205

X-ray absorption spectroscopy studies of nickel oxide thin film electrodes for supercapacitors  

Microsoft Academic Search

Nickel oxide films were synthesized by electrochemical precipitation of Ni(OH)2 followed by heat-treatment in air at various temperatures (200–600°C). Their structure and electrochemical properties were studied by cyclic voltammetry, X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). XRD results showed that the nickel oxide obtained at 250°C or above has a crystalline NiO structure. The specific capacitance of the oxide

Kyung-Wan Nam; Won-Sub Yoon; Kwang-Bum Kim

2002-01-01

206

An X-ray absorption spectroscopy investigation of speciation and biotransformation of copper in Elsholtzia splendens  

Microsoft Academic Search

Elsholtzia splendens is a Cu-tolerant plant growing in copper mine areas in the south of China. In this study, X-ray absorption spectroscopy (XAS)\\u000a was used to investigate the Cu speciation and biotransformation in E. splendens with 300 ?M Cu treatment from 10 days to 60 days. The results showed that 300 ?M Cu was phytotoxic to E. spendens. The Cu K-edge X-ray absorption near

Jiyan Shi; Bei Wu; Xiaofeng Yuan; Cao YY; Xincai Chen; Yingxu Chen; Tiandou Hu

2008-01-01

207

Chemical shifts in X-ray and photo-electron spectroscopy: a historical review  

Microsoft Academic Search

A review with historical emphasis is given of the discovery and evaluation of chemical shifts in X-ray and photo-electron spectroscopy. The discovery and interpretation of the shifts in the X-ray spectra in the early 1920s are treated as an introduction and general background. The discovery of the shifts in photo-electron spectra, discovered in the late 1950s, and its interpretation, which

Ingvar Lindgren

2004-01-01

208

New developments in fabrication of high-energy-resolution analyzers for inelastic X-ray spectroscopy  

PubMed Central

In this work new improvements related to the fabrication of spherical bent analyzers for 1?meV energy-resolution inelastic X-ray scattering spectroscopy are presented. The new method includes the use of a two-dimensional bender to achieve the required radius of curvature for X-ray analyzers. The advantage of this method is the ability to monitor the focus during bending, which leads to higher-efficiency analyzers.

Said, Ayman H.; Sinn, Harald; Divan, Ralu

2011-01-01

209

New developments in fabrication of high-energy-resolution analyzers for inelastic x-ray spectroscopy.  

SciTech Connect

In this work new improvements related to the fabrication of spherical bent analyzers for 1 meV energy-resolution inelastic X-ray scattering spectroscopy are presented. The new method includes the use of a two-dimensional bender to achieve the required radius of curvature for X-ray analyzers. The advantage of this method is the ability to monitor the focus during bending, which leads to higher-efficiency analyzers.

Said, A. H.; Sinn, H.; Divan, R. (Center for Nanoscale Materials); ( XSD); (XFEL Hamburg)

2011-05-01

210

Charge Transfer Excitation in Resonant X-ray Emission Spectroscopy of NiO  

Microsoft Academic Search

We analyze Ni 2 p \\\\to 3d \\\\to 2 p resonant X-ray emission spectroscopy (RXES) of NiO with the impurity Anderson model. We pay attention to the inelastic X-ray scattering structures arising from the interatomic charge transfer (CT) from ligand state to 3d state. We take into account a finite width of the O 2 p valence band in order

Masahiko Matsubara; Takayuki Uozumi; Akio Kotani; Jean Claude Parlebas

2005-01-01

211

Design and Operation of a High Pressure Reaction Cell for in situ X-ray Absorption Spectroscopy  

SciTech Connect

X-ray absorption spectroscopy measurements of catalytic reactions have been instrumental in advancing the understanding of catalytic processes. These measurements require an in situ catalysis reaction cell with unique properties. Here we describe the design and initial operation of an in situ/operando catalysis reaction cell for transmission X-ray absorption spectroscopy measurements. The cell is designed: to be an ideal catalytic reactor with no mass transfer effects; to give the same conversion and selectivity under similar space velocities as standard laboratory micro-reactors; to be operational temperatures up to 600 {sup o}C and pressures up to 14 bar; to be X-ray transparent allowing XAS measurement to be collected in transmission for all elements with Z {>=} 23 (vanadium K-edge at 5.5 keV); to measure the actual catalyst bed temperature; to not use o-ring seals, or water cooling; to be robust, compact, easy to assemble, and use, and relatively low cost to produce. The heart of the cell is fabricated from an X-ray transparent beryllium tube that forms a plug flow reactor. XAFS data recorded during the reduction of a Re/{gamma}-A{sub 2}O{sub 3} catalyst as a function of hydrogen pressure from 0.05 to 8 bar, and from a Pt-Sn/{gamma}-A{sub 2}O{sub 3} catalyst during n-heptane reforming are given as initial examples of the versatility of the reactor.

Bare,S.; Yang, N.; Kelly, S.; Mickelson, G.; Modica, F.

2007-01-01

212

Multi waveband science with UVIT & X-ray instruments on Astrosat.  

NASA Astrophysics Data System (ADS)

The UVIT instrument on Astrosat is designed to cover the 130-550nm band, using 3 detectors (FUV, NUV, and VIS) on two optical assemblies. This talk will cover the scientific capabilities of UVIT, especially vis-a-vis earlier UV missions, and the other (X-ray) instruments on board Astrosat. The scientific potential of UVIT will be discussed in detail, specifically in the fields of supernovae and hot compact objects studies, but also for other UV and X-ray bright, galactic and extra-galactic objects. Some details of the planned in-orbit calibrations (e.g. timing etc.) will also be presented, for cases when the targets are common to all Astrosat instruments.

Sutaria, Firoza; Hutchings, John; Ghosh, Swarna

2012-07-01

213

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

SciTech Connect

Facilities for small angle x-ray and neutron scattering are described, with emphasis on the characterization of the primary beam of the neutron instrument and the spectrometer control logic of the synchrotron instrument. (LEW)

Schoenborn, B.P.; Wise, D.S.; Schneider, D.K.

1983-01-01

214

Enrichment study of hot intra-cluster gas through X-ray spectroscopy  

NASA Astrophysics Data System (ADS)

Enrichment study of hot intra-cluster gas through X-ray spectroscopy Clouds of hot X-ray emitting gas associated with clusters of galaxies are the biggest aggregates of baryons that we know, except for the cosmic web. A typical cloud contains the nuclear-fusion products of billions of supernovae. Therefore, they are representative objects to study the enrichment of the bulk of the matter in the universe. The elemental abundances in this hot Intra-Cluster Medium (ICM) are able to reveal the clusters enrichment history and they can also be used to constrain supernova models. Using the current state-of-the-art in high-resolution X-ray spectroscopy, XMM-Newton, Jelle de Plaa has analysed data of 23 clusters of galaxies in total. He finds that detailed knowledge about the X-ray background, spectral lines, and the response of the instruments is absolutely necessary to obtain accurate abundances with realistic uncertainties. To improve the accuracy on the abundances and their uncertainties, he has developed a method to correct for the soft X-ray background. Moreover, systematic differences between the instruments also need to be taken into account. Therefore, analysis of extended sources, like clusters, cannot be done using a black-box approach, but a large effort is needed to extract robust values. Only when robust values are obtained, one can attempt to derive the enrichment history. De Plaa shows that EPIC and RGS can be used to obtain information about the spatial abundance distribution in clusters. From the RGS spectrum of Sérsic 159-03, he derives that the iron abundance profile (a typical supernova type Ia product) is peaked around the central cluster galaxy, while the oxygen abundance distribution (a typical core-collapse supernova product) is more extended. This confirms the idea that iron is still being added to the ICM specifically in the core by the supernovae type Ia, and that oxygen is an old well-mixed product of the core-collapse supernovae that exploded soon after the first star bursts. The spatial oxygen distribution is not required to be entirely flat, but may exhibit a more shallowly peaked distribution due to ram-pressure stripping of gas from in-falling galaxies. Perhaps this is the case in 2A 0335+096, were he finds a similar spatial profile for oxygen and iron with RGS. The abundances that he measures also provide constraints on the supernovae themselves. He concludes that the currently favoured supernova models are not able to match our data. An empirically modified supernova type Ia model provides a better fit to the Ar/Ca ratio that he finds. The fitted abundances can provide information to constrain physical parameters of type Ia supernovae, like the density where the sound wave that is ahead of the explosion turns into a shock. In his final chapter, De Plaa argues that new deep observations of clusters with XMM-Newton or future observatories will provide much more insight into supernova explosions and the enrichment of the largest bound objects we know.

de Plaa, J.

2007-02-01

215

Applications of X-ray absorption spectroscopy to biologically relevant metal-based chemistry  

NASA Astrophysics Data System (ADS)

Recent developments in the understanding of the biosynthesis of the active site of the nitrogenase enzyme, the structure of the iron centre of [Fe]-hydrogenase and the structure and biomimetic chemistry of the [FeFe] hydrogenase H-cluster as deduced by application of X-ray spectroscopy are reviewed. The techniques central to this work include X-ray absorption spectroscopy either in the form of extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES) and nuclear resonant vibrational spectroscopy (NRVS). Examples of the advances in the understanding of the chemistry of the system through integration of a range of spectroscopic and computational techniques with X-ray spectroscopy are highlighted. The critical role played by ab initio calculation of structural and spectroscopic properties of transition-metal compounds using density functional theory (DFT) is illustrated both by the calculation of nuclear resonance vibrational spectroscopy (NRVS) spectra and the structures and spectra of intermediates through the catalytic reactions of hydrogenase model compounds.

Best, Stephen P.; Cheah, Mun Hon

2010-02-01

216

Structural characterization of SrLaMnRuO 6 by synchrotron X-ray powder diffraction and X-ray absorption spectroscopy  

Microsoft Academic Search

Single-phase polycrystalline powder samples of SrLaMnRuO6 were prepared by solid-state synthesis method and its crystal structure was studied using synchrotron X-ray diffraction and X-ray absorption spectroscopies. The Rietveld analysis of the room temperature synchrotron X-ray diffraction data shows that it has a double perovskite structure with disordered arrangements of Sr\\/La and Mn\\/Ru and adopts orthorhombic space group Pbnm [a=5.5004(3)Å, b=5.5445(3)Å,

Javaid Bashir; Rubina Shaheen; Muhammad Nasir Khan

2008-01-01

217

Chemical bonding on surfaces probed by X-ray emission spectroscopy and density functional theory  

Microsoft Academic Search

X-ray emission spectroscopy applied to surface adsorbates is an experimental technique that provides an atom-specific projection of the electronic structure. In combination with theoretical density functional spectrum simulations, it becomes an extremely powerful tool to analyze in detail the surface chemical bond. The present review discusses both the experimental and computational techniques related to the spectroscopy and summarizes all applications

Anders Nilsson; Lars Gunnar Moody Pettersson

2004-01-01

218

Near-Edge X-ray Absorption Fine-Structure, X-ray Photoemission, and Fourier Transform Infrared Spectroscopies of Ultrananocrystalline Diamond\\/Hydrogenated Amorphous Carbon Composite Films  

Microsoft Academic Search

The chemical bonding structure of ultrananocrystalline diamond (UNCD)\\/hydrogenated amorphous carbon (a-C:H) composite films prepared by pulsed laser deposition was examined by near-edge X-ray absorption fine-structure (NEXAFS), X-ray photoemission, and Fourier transform infrared (FTIR) spectroscopies. An intense sp3-CH peak was observed in the FTIR spectrum. This implies that the sp3-CH peak originates from the grain boundaries between UNCD crystallites, wherein dangling

Tsuyoshi Yoshitake; Akira Nagano; Shinya Ohmagari; Masaru Itakura; Noriyuki Kuwano; Ryota Ohtani; Hiroyuki Setoyama; Eiichi Kobayashi; Kunihito Nagayama

2009-01-01

219

Applications of Synchrotron-Based X-Ray Diffraction and X-Ray Absorption Spectroscopy to the Understanding of Poorly Crystalline and Metal-Substituted Iron Oxides  

Microsoft Academic Search

The octahedral site in iron oxides has been shown to undergo changes in its occupation when iron oxides form in the presence of single and multiple foreign metals in controlled laboratory settings as well as the natural environment. X-ray absorption spectroscopy coupled with the increased precision of synchrotron-based X-ray diffraction (SXRD) have shed new light on important basic mechanisms controlling

Balwant Singh; Markus Gräfe; Navdeep Kaur; Andrea Liese

2010-01-01

220

High-resolution soft-X-ray beamline ADRESS at Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies  

Microsoft Academic Search

We describe the concepts and technical realization of the high-resolution soft-X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for Resonant Inelastic X-ray Scattering (RIXS) and Angle-Resolved Photoelectron Spectroscopy (ARPES). The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including

V. N. Strocov; T. Schmitt; U. Flechsig; T. Schmidt; A. Imhof; Q. Chen; J. Raabe; R. Betemps; D. Zimoch; J. Krempasky; A. Piazzalunga; X. Wang; M. Grioni; L. Patthey

2009-01-01

221

Oxidation study of polycrystalline InN film using in situ X-ray scattering and X-ray photoemission spectroscopy  

Microsoft Academic Search

Oxidation process of polycrystalline InN films were investigated using in situ X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS). The films were grown by dc sputter on sapphire (0001) substrates and were oxidized in air at elevated temperatures. The XRD data showed that the structure of the films changed to the bixbyite In2O3 (a=10.11 Å) above 450 °C. Chemical configurations of the

Ik Jae Lee; Chungjong Yu; Hyun-Joon Shin; Jae-Yong Kim; Young Pak Lee; Tae-Bong Hur; Hyung-Kook Kim

2007-01-01

222

Electronic structure and optical properties of silicon nanowires: A study using x-ray excited optical luminescence and x-ray emission spectroscopy  

Microsoft Academic Search

We report a soft x-ray excited optical luminescence (XEOL) and x-ray emission spectroscopy (XES) study of silicon nanowires (SiNW) with excitations at the silicon K and L3,2 edge, respectively. It is found that the XEOL of SiNW exhibits several luminescence bands at ˜460 , ˜530 , and ˜630nm . These luminescence bands are broad and are sensitive to the Si1s

T. K. Sham; S. J. Naftel; P.-S. G. Kim; R. Sammynaiken; Y. H. Tang; I. Coulthard; A. Moewes; J. W. Freeland; Y.-F. Hu; S. T. Lee

2004-01-01

223

High-Resolution Soft X-ray Spectroscopy of a Gamma-ray Burst X-ray Afterglow  

Microsoft Academic Search

We propose a deep TOO observation of a bright X-ray afterglow of a gamma-ray burst using the Chandra LETG\\/ACIS-S. The trigger will be based primarily on the X-ray flux, which will be monitored with the X-ray Telescope on board the Swift observatory. An additional constraint on the line-of-sight Galactic column density will be imposed as well to provide the highest

Masao Sako

2005-01-01

224

Chandra X-ray Observatory High-Resolution X-ray Spectroscopy of Stars: Modeling and Interpretation  

Microsoft Academic Search

The Chandra X-Ray Observatory grating spectrometers allow us to study stellar spectra at resolutions on the order of 1000. Prior X-ray observatories' low resolution data have shown that nearly all classes of stars emit X-rays. With Chandra, we can study in detail the line and continuum contributions to the spectra and apply atomic databases in plasma models. For cool stars

David Huenemoerder

2003-01-01

225

High-Resolution Soft X-ray Spectroscopy of a Gamma-ray Burst X-ray Afterglow  

Microsoft Academic Search

We propose a deep TOO observation of a bright X-ray afterglow of a gamma-ray burst using the Chandra LETG\\/ACIS-S. The trigger will be based primarily on the X-ray flux, which will be monitored with the X-ray Telescope on board the Swift observatory. An additional constraint on the line-of-sight Galactic column density will be imposed as well to provide the highest

Masao Sako

2006-01-01

226

Ultrafast laser-driven x-ray spectrometer for x-ray absorption spectroscopy of transition metal complexes  

Microsoft Academic Search

We report what are to our knowledge the first measurements of an x-ray absorption near-edge structure (XANES) spectrum of solvated iron pentacarbonyl by use of an ultrafast laser-driven plasma x-ray source. This source is operating at a 2-kHz repetition rate. Hard x radiation that might falsify the XANES measurements is suppressed by an x-ray optical setup that consists of a

Frank Benesch; Taewoo Lee; Yan Jiang; Christoph G. Rose-Petruck

2004-01-01

227

Polychromatic X-ray Micro- and Nano-Beam Science and Instrumentation  

SciTech Connect

Polychromatic x-ray micro- and nano-beam diffraction is an emerging nondestructive tool for the study of local crystalline structure and defect distributions. Both long-standing fundamental materials science issues, and technologically important questions about specific materials systems can be uniquely addressed. Spatial resolution is determined by the beam size at the sample and by a knife-edge technique called differential aperture microscopy that decodes the origin of scattering from along the penetrating x-ray beam. First-generation instrumentation on station 34-ID-E at the Advanced Photon Source (APS) allows for nondestructive automated recovery of the three-dimensional (3D) local crystal phase and orientation. Also recovered are the local elastic-strain and the dislocation tensor distributions. New instrumentation now under development will further extend the applications of polychromatic microdiffraction and will revolutionize materials characterization.

Ice, Gene E [ORNL; Larson, Ben C [ORNL; Liu, Wenjun [ORNL; Barabash, Rozaliya [ORNL; Specht, Eliot D [ORNL; Pang, Judy [ORNL; Budai, John D [ORNL; Tischler, Jonathan Zachary [ORNL; Khounsary, Ali [Argonne National Laboratory (ANL); Liu, Chian [Argonne National Laboratory (ANL); Macrander, Albert T. [Argonne National Laboratory (ANL); Assoufid, Lahsen [Argonne National Laboratory (ANL)

2007-01-01

228

Ultrafast conversions between hydrogen bonded structures in liquid water observed by femtosecond x-ray spectroscopy  

SciTech Connect

We present the first femtosecond soft x-ray spectroscopy in liquids, enabling the observation of changes in hydrogen bond structures in water via core-hole excitation. The oxygen K-edge of vibrationally excited water is probed with femtosecond soft x-ray pulses, exploiting the relation between different water structures and distinct x-ray spectral features. After excitation of the intramolecular OH stretching vibration, characteristic x-ray absorption changes monitor the conversion of strongly hydrogen-bonded water structures to more disordered structures with weaker hydrogen-bonding described by a single subpicosecond time constant. The latter describes the thermalization time of vibrational excitations and defines the characteristic maximum rate with which nonequilibrium populations of more strongly hydrogen-bonded water structures convert to less-bonded ones. On short time scales, the relaxation of vibrational excitations leads to a transient high-pressure state and a transient absorption spectrum different from that of statically heated water.

Wen, Haidan; Huse, Nils; Schoenlein, Robert W.; Lindenberg, Aaron M.

2010-05-01

229

A stored-ion target for x-ray spectroscopy of multicharged ions  

SciTech Connect

With the evolution of the new third generation synchrotron radiation sources providing intense beams of hard x-rays, it is natural to consider exploiting these to investigate the 3-body Coulomb problem. The atomic physics community could advance this field considerably by developing general techniques to investigate the x-ray spectroscopy of heliumlike ions. To do so, however, requires the development of a target of such ions with sufficient density to permit photoexcitation studies in the hard x-ray regime. A possible scheme to achieve this is described. Such a target system would permit x-ray studies with exotic species such as highly charged atomic ions, size-selected cluster ions, and atomic and molecular negative ions which have hitherto been impractical to study with conventional techniques.

Kanter, E.P.

1996-08-01

230

Chandra high-resolution X-ray spectroscopy of Seyfert 1 galaxies  

NASA Astrophysics Data System (ADS)

We present the analysis of the X-ray spectra of the Seyfert 1 galaxies NGC 5548 and Mrk 279. The X-ray spectra were obtained with the LETGS and HETGS spectrometers of Chandra during two long campaigns involving HST-STIS for both sources as well as FUSE for Mrk 279. The combination of both the X-ray and UV spectroscopy allowed us to obtain unique spectral diagnostics of the AGN outflow. We found absorption lines spanning several orders of magnitude in ionization parameter. The derived column densities are in good agreement with models involving density-stratified streamer-like outflows. In addition to the narrow absorption lines, we found both narrow and broad X-ray emission lines, with physical parameters very similar to the optical/UV narrow and broad line regions. The Space Research Organization Netherlands is supported financially by NWO, the Netherlands Organization for Scientific Research.

Kaastra, J. S.

2004-05-01

231

Molecular structural dynamics probed by ultrafast X-ray absorption spectroscopy.  

PubMed

The ability to visualize molecular structure in the course of a chemical reaction or a biological function has been a dream of scientists for decades. X-ray absorption spectroscopy (XAS) is ideal in this respect because it is chemically selective and can be implemented in any type of medium. Furthermore, using X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) in laser pump/X-ray probe experiments allows the retrieval of not only the local geometric structure of the system under study, but also the underlying electronic structure changes that drive the structural dynamics. We review recent developments in picosecond and femtosecond XAS applied to molecular systems in solution. Examples on ultrafast photoinduced processes such as intramolecular electron transfer, low-to-high spin change, and bond formation are presented. PMID:20055677

Bressler, Christian; Chergui, Majed

2010-01-01

232

I20; the Versatile X-ray Absorption spectroscopy beamline at Diamond Light Source  

NASA Astrophysics Data System (ADS)

The Versatile Spectroscopy beamline at Diamond Light Source, I20, is currently under construction and aims to begin operation in late 2009 and early 2010. The beamline aims to cover applications from physics, chemistry and biology through materials, environmental and geological science. Three very distinctive modes of operation will be offered at the beamline: scanning X-ray Absorption spectroscopy (XAS), XAS in dispersive mode, and X-ray emission spectroscopy (XES). To achieve this, the beamline has been designed around two independent experimental end-stations operating from a pair of canted wigglers located in a 5m diamond straight section. One branch of the beamline will deliver monochromatic x-ray radiation of high spectral purity to one of the experimental hutches, whilst the other branch will constitute an energy dispersive spectrometer. The novel design of the beamline allows both branches to operate simultaneously.

Diaz-Moreno, S.; Hayama, S.; Amboage, M.; Freeman, A.; Sutter, J.; Duller, G.

2009-11-01

233

X-ray photoemission and energy dispersive spectroscopy of hydroxyapatite-coated titanium  

SciTech Connect

The purpose of this study was to determine the chemical composition changes of hydroxyapatite (HA) coated titanium using surface analysis (X-ray photoemission) and bulk analysis (energy dispersive spectroscopy). The specimens examined were controls and specimens aged 30 min and 3 h at room temperature in distilled water and 0.2M sodium phosphate buffer (pH 7.2). Each X-ray photoemission cycle consisted of three scans followed by argon sputtering for 10 min for usually 20 cycles, corresponding to a sampling depth of {approximately}1,500 {angstrom}. The energy dispersive spectroscopy analysis was on a 110 by 90 {micro}m area for 500 s. The X-ray photoemission results indicated the oxidation effect of water on the titanium (as TiO{sub 2}) and the effect of the buffer to increase the surface concentration of phosphorus. No differences in the chemical composition were observed by energy dispersive spectroscopy analysis.

Drummond, J.L.; Steinberg, A.D. [Univ. of Illinois, Chicago, IL (United States). Coll. of Dentistry; Krauss, A.R. [Argonne National Lab., IL (United States)

1997-07-01

234

Ultra-soft x-ray absorption spectroscopy: A bulk and surface probe of materials  

SciTech Connect

Direct comparisons between surface and bulk of diverse materials can be made by simultaneous electron yield (5 nm depth sensitivity) and fluorescence yield (200 nm) ultra soft x-ray absorption spectroscopy measurements utilizing a rapid sample interchange apparatus. For example the orientations of functional groups have been characterized at and near the surface of a series of model polymeric materials highlighting the chemical and molecular sensitivity of ultra soft x-ray absorption spectroscopy. In addition we discuss a bulk sensitive use of fluorescence yield to non destructively study a buried metal polymer interface. A second bulk sensitive example is the use of fluorescence yield oxygen K near edge x-ray spectroscopy as a method to determine the hole state density of high Tc materials.

Fischer, D.A. [National Institute of Standards and Technology, Gaithersburg, MD (United States); Mitchell, G.E.; Dekoven, B.M. [Dow Chemical Co., Midland, MI (United States); Yeh, A.T.; Gland, J.L. [Michigan Univ., Ann Arbor, MI (United States); Moodenbaugh, A.R. [Brookhaven National Lab., Upton, NY (United States)

1993-06-01

235

Ultra-soft x-ray absorption spectroscopy: A bulk and surface probe of materials  

SciTech Connect

Direct comparisons between surface and bulk of diverse materials can be made by simultaneous electron yield (5 nm depth sensitivity) and fluorescence yield (200 nm) ultra soft x-ray absorption spectroscopy measurements utilizing a rapid sample interchange apparatus. For example the orientations of functional groups have been characterized at and near the surface of a series of model polymeric materials highlighting the chemical and molecular sensitivity of ultra soft x-ray absorption spectroscopy. In addition we discuss a bulk sensitive use of fluorescence yield to non destructively study a buried metal polymer interface. A second bulk sensitive example is the use of fluorescence yield oxygen K near edge x-ray spectroscopy as a method to determine the hole state density of high Tc materials.

Fischer, D.A. (National Institute of Standards and Technology, Gaithersburg, MD (United States)); Mitchell, G.E.; Dekoven, B.M. (Dow Chemical Co., Midland, MI (United States)); Yeh, A.T.; Gland, J.L. (Michigan Univ., Ann Arbor, MI (United States)); Moodenbaugh, A.R. (Brookhaven National Lab., Upton, NY (United States))

1993-01-01

236

Potential of the PANTER x-ray test facility for calibration of instrumentation for XEUS  

NASA Astrophysics Data System (ADS)

The PANTER X-ray Test Facility was originally designed to support the development and construction of the ROSAT mirror system. A large instrument chamber (length 12 m, diameter 3.5m) accommodates the optics to be analysed. The X-ray sources covering an 0.2 - 50 keV energy range are located at a distance of 123m from the entrance to the chamber to provide an almost parallel X-ray beam. Both are connected by a vacuum tube of 1m diameter. In addition to ROSAT a large number of astronomical systems like telescopes for Exosat, BeppoSAX, JET-X, ABRIXAS, XMM-Newton and Swift - but also gratings (e.g., LETG on Chandra), filters, and focal plane detectors have been measured at the facility. As a "growing facility" we are currently planning to apply changes to the facility layout to support measurements of instrumentation for future missions like XEUS. Currently a parallel beam is set up using a spare CDS mirror ("Coronal Diagnostic Spectrometer", for the SOHO mission) as condensor. Moreover, extensions to vacuum tube and instrument chamber are under consideration, both to allow calibration of systems with focal lengths significantly longer than XMM-Newton. A new focal plane camera using a CCD developed for the eROSITA mission will improve spatial and spectral resolution. Finally, the energy coverage shall be extended to lower and to higher energies. Already with the present configuration important issues like performance under low temperatures could be investigated.

Freyberg, Michael; Budau, Bernd; Burkert, Wolfgang; Hartner, Gisela; Hasinger, Günther; Collon, Maximilien; Kraft, Stefan; Beijersbergen, Marco; Bavdaz, Marcos; Lumb, David; Wallace, Kotska; Kampf, Dirk

2006-07-01

237

X-ray Spectroscopy of Directly Driven Cylindrical Implosions  

NASA Astrophysics Data System (ADS)

X-ray spectra from a chlorinated polystyrene marker layer in a series of directly driven cylindrical implosions are presented and analyzed. The 4?m thick, 500?m long C_8H_6Cl2 (1.42g/cc) annular spectroscopic tracer layer is centrally located on the interior surface of the 20?m thick, 2250?m long polystyrene (1.044g/cc) 860? m inner diameter cylindrical shell. The shell is filled with polystyrene foam (60mg/cc).(Barnes, C. W., et al.) 1998, to be published in Rev. Sci. Instrum., Tubbs, D. L., et al. 1998, to be published in Lasers and Particle Beams The implosions are driven by 50 beams of the OMEGA Laser facility. The temperature and density sensitive K-shell Cl spectra are recorded by a time-resolved spectrograph, and compared to calculated spectra in order to infer the evolution of electron temperature and density in the marker layer.(This work was performed under the auspices of the U. S. Department of Energy by the Los Alamos National Laboratory under contract No. W-7405-Eng-36)

Haynes, D.; Hooper, C.; Delamater, N.; Barnes, C.; Oertel, J.; Pollak, G.; Tubbs, D.; Watt, R.; Boehly, T.; Bradley, D.; Jaanimagi, P.; Knauer, J.

1998-11-01

238

Aluminum impurities in silicon: Investigation of x-ray Raman scattering in total reflection x-ray fluorescence spectroscopy  

Microsoft Academic Search

Total reflection x-ray fluorescence using synchrotron radiation from the Stanford Synchrotron Radiation Laboratory has been used to study Al impurities on Si wafer surfaces. For primary excitation energies below the Si K absorption edge an inelastic resonance scattering due to resonant x-ray Raman scattering is observed. This scattering dominates the background behavior of the Al K fluorescence line, and consequently

K. Baur; J. Kerner; S. Brennan; A. Singh; P. Pianetta

2000-01-01

239

Portable X-ray fluorescence instruments for the analysis of lead in paints.  

PubMed Central

In a study in the laboratories of the Chicago Board of Health, the results from determination of lead in paint films by X-ray fluorescence were compared with results from determination by atomic absorption. Portable instruments of three suppliers were used for X-ray fluorescence measurements. An improved version of one of these instruments was also tested. The results of X-ray fluorescence readings on painted card stock panels with one of these instruments compared satisfactorily with the results as determined by the atomic absorption method at levels below 10 mg of lead per square centimeter. Readings on multiple layers of these panels were additive and independent of the order of these panels. All four instruments were tested in the laboratory on painted surfaces from the walls of condemned buildings. The most recent version of each instrument gave a correlation coefficient of 0.96 or better for the linear regression of lead values in milligrams per square centimeter by atomic absorption against instrument readings. It was calculated that a reading of 3.2 or greater on any of the instruments would indicate with greater than 95 percent confidence that 1 mg or more of lead per square centimeter would be found when a sample of the paint was analyzed by atomic absorption. When the readings of one of the instruments showed lead to be absent, that result would inidcate with better than 95 percent confidence that less than 1 mg of lead per square centimeter would be found by the atomic absorption method. Portable X-ray fluorescence instruments can be used in situ to determine whether the walls of a building give readings for lead above the range of 0 to 3.2. Walls with readings above this range can be considered to have 1 mg or more of lead per square centimeter and would not be in conformance with the code of the City of Chicago. Samples would need to be taken for analysis in the laboratory by atomic absorption only from those walls with readings within the range of 0 to 3.2. Images p224-a 1. 2. 3.

Kaplan, E H; Lilley, M D; Schaefer, R F; Cade, B; Desai, A; Padva, A; Orbach, H G

1975-01-01

240

X-Ray Absorption Spectroscopy Determination of Oxidation States  

NASA Astrophysics Data System (ADS)

Introduction: The oxidation state of minor and trace elements in minerals from planetary materials can be used to directly probe the oxygen fugacity of the environment from which the minerals formed. For example, on the basis of existing oxygen fugacity determinations it has been suggested that the parent bodies of chondrites were > 30 km in diameter [1]. Petrogenetic models generally assume oxygen fugacities based on indirect evidence. The x-ray microprobe offers the capability to determine oxidation states for a large suite of elements in individual coexisting phases in conventional rock thin sections using the microXANES (X-ray Absorption Near Edge Structure) technique. Recent Results: Initial research has concentrated on transition metals particularly Cr. The results on Cr oxidation state for olivine and pyroxene from mare basalts 15555 [2] showed that olivine contains predominately divalent Cr while pyroxene accommodates Cr mainly in trivalent state. Similar results for olivine from kimberlitic diamonds showed a mixture of the two states [3]. These results suggest that the terrestrial olivine crystallized in a more oxidizing environment than the lunar olivine and that divalent chromium is a ubiquitous component of olivine crystallized under reducing conditions. Calibration of the method in terms of oxygen fugacity requires the analysis of synthetic olivine crystallized from melts of appropriate composition at controlled fO(sub)2 [4]. MicroXANES analyses of Fe surprisingly suggested that Fe in plagioclase from lunar anorthosite 15415 is more oxidized than that in plagioclase from Stillwater anorthosites and shergottites [5]. Recently, iron oxide specimens were analyzed, specifically, magnetite (Fe3O4), hematite (Fe2O3) and altered magnetites (i.e., magnetites suspected of containing substantial alteration to hematite). The results showed that the altered magnetites are roughly equal mixtures of magnetite and hematite [6]. Future Research: The work on lunar olivines in lunar basalts is being extended to lunar olivines in highlands rocks. Oxygen fugacities of the early lunar magmas will be compared with those of the latter mare systems. Determinations of Cr oxidation state in olivine from carbonaceous meteorites are also being pursued but the Cr content of olivine from primitive meteorites is close to current detection limit with microXANES (about 10 ppm). MicroXANES will also provide valuable information on the oxidation states of transition elements in primitive interplanetary dust particles (IDPs). Preliminary results on one IDP indicated that Fe was in both the divalent and trivalent states and the shape of the spectrum is inconsistent with an oxide host. This technique will also be useful in estimating magnetite content in heated IDPs. Iron oxidation states of SNC meteorites and other achondrites will be valuable in constraining the oxygen fugacity of igneous planetary systems. Measurements of Ti^3+, Ti^4+, V^2+ and V^3+ in the constituent phases of CAIs will help to constrain the chemical history of materials that formed in the early solar nebula. The next generation synchrotron source, the Advanced Photon Source at Argonne National Laboratory, will be available for use by planetary scientists in 1996 and will extend these techniques to 1 ppm detection limits and 1 micrometer spatial resolution. References: [1] Rubin A. E. et al. (1988) In Meteorites and the Early Solar System, 488-511. [2] Sutton S. R. et al. (1993) GCA, 57-2, 461-468. [3] Sutton S. R. et al. (1993) LPS XXIV, 1383- 1384. [4] Hanson B. Z. and Delano J. W. (1992) LPS XXIII, 481- 482. [5] Delaney J. S. et al. (1992) LPS XXIII, 299-300. [6] Sutton S. R. et al. (1993) LPS XXIV, 1385-1386.

Bajt, S.; Sutton, S. R.; Smith, J. V.

1993-07-01

241

Advanced x-ray/EUV diagnostics for spectroscopy, imaging, and polarimetry at the Nevada Terawatt Facility z-pinch plasma source  

NASA Astrophysics Data System (ADS)

A wide variety of x-ray and extreme ultraviolet (EUV) diagnostics are being developed to study z-pinch plasmas at the Nevada Terawatt Facility (NTF) at the University of Nevada, Reno. Time-resolved x-ray/EUV imaging and spectroscopy, polarization spectroscopy, and backlighting will be employed to measure profiles of plasma temperature, density, flow, and charge state and to investigate electron distribution functions and magnetic fields. These diagnostics are used to study the NTF pinch as an x-ray/EUV source for plasma spectroscopy research and to examine the early-time evolution of a current-driven wire, the formation of a plasma sheet from the explosion and merging of wires, etc. The instruments are state-of-the-art applications of glass capillary converters (GCC), multilayer mirrors (MLM), and crystals. Devices include: a novel glass-capillary-based two- dimensional imaging spectrometer, a time-resolved x-ray spectrometer, a 5-channel crystal/MLM spectrometer ('Polychromator') with a transmission grating spectrometer, and two-channel x-ray/EUV polarimeters-spectrometers (to study simultaneously polarization of K- and L-shell radiation). An x-pinch backlighter, yielding point-projection microscopy with ns resolution is under development. X-ray convex-crystal survey spectrometers, and fast filtered x-ray diodes have observed single Ti-, Fe and W-wire z-pinches, and Ti and Fe x- pinches. The NTF x-ray yield and x-ray pulse duration depend sensitively on the wire load. There is evidence of a strong energetic electron beam with a complex spatial structure in x- pinch plasmas. This work is supported by DOE, DOD, SNL, and UNR.

Kantsyrev, Victor L.; Bauer, Bruno S.; Shlyaptseva, Alla S.; Fedin, Dmitry A.; Hansen, Stephanie; Presura, Radu; Chamberlain, David; Ouart, Nick; Jones, Alex; LeBeau, Hank

2000-11-01

242

Superconducting tunnel junction x-ray detectors for high resolution spectroscopy  

SciTech Connect

We are developing low-tcmpaature detectors for optical, ultraviolet, X-ray, and gamma-ray spectroscopy, and for biomolecular mass spectrometry. We present here a some of our recent work in developing these detectors and some of the first results in applying these detectors to X-ray fluorescence analysis. We have measured thin-film Nb/Al/Al{sub 2}O{sub 3}/Al/Nb superconducting tunnel junction (STJ) X-ray detectors in the 0 2 to 1 keV band with a range of different junction sizes and aluminum film thicknesses. In one case, we have achieved the statistical limit to the energy resolution in this band. We have measured the performance of these STJ detectors as a function of count rate. and demonstrated a resolution of 13 eV FWHM at 271 eV with an output count rate of 20,600 cts/s Using X rays from SSRL to study compos- ite materials, we have demonstrated that we can resolve the L lines of transition metals from the nearby K lines of light elements We describe the first use of a low-temperature X-ray detector to measure X-ray fluoresccncc from the dilute metal component in a protein.

Labov, S., LLNL

1998-06-01

243

Surface Dynamics of Block Copolymer Films by X-ray Photon Correlation Spectroscopy  

SciTech Connect

We investigated the structure and dynamics of supported block copolymer films of poly(styrene)-b-poly(dimethylsiloxane)(PS-b-PDMS) in the spherical phase by x-ray photon correlation spectroscopy (XPCS) in grazing angle geometry. The temperature range studied was between 160 deg. and 210 deg. C, much higher than glass transition temperature (Tg), with thickness from 40 nm to 600 nm. Using x-ray reflectivity and x-ray photoelectron spectroscopy (XPS), we found that the PDMS-rich layer near the surface appeared at a temperature higher than Tg. Universal scaling of the dynamics, even with the bilayer model, was observed. From the fitting with the bilayer model, viscosities from both layers were obtained. The results from the surface dynamics are compared with the theory of overdamped thermal capillary waves on thin films.

Song, Sanghoon; Cha, Wonsuk; Lee, Heeju; Li, Xiaolong; Kim, Hyunjung [Department of Physics and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul (Korea, Republic of); Jiang, Zhang [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois (United States); Department of Physics, University of California San Diego, La Jolla, California (United States); Narayanan, Suresh [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois (United States); Ruehm, Adrian [Max Planck Institute for Metal Research, Stuttgart (Germany); Sinha, S. K. [Department of Physics, University of California San Diego, La Jolla, California (United States)

2009-04-19

244

X-ray spectroscopy with the XSPECT/SODART telescopes on SRG.  

NASA Astrophysics Data System (ADS)

The XSPECT/SODART X-ray telescopes and their associated focal plane instrumentation will be launched on board the Russian X-ray mission Spectrum Röntgen-Gamma (SRG). The authors first present the main properties of the instruments and then present simulations of some of the scientific questions which can be addressed by the observing program. XSPECT/SODART consists of two, high-throughput telescopes. In the focal plane of each one, there are high- and low energy imaging proportional counters. One telescope also has an array of silicon detectors and the other a polarimeter. An imaging, objective spectrometer consisting of three different kinds of Bragg crystals and two different multilayers is mounted in front of one of the telescopes. The broad bands of the imaging X-ray detectors collectively cover the energy rangy from 0.2 to 25 keV. The objective spectrometer samples this range around the emission and absorption features from, among others, the cosmically important ions of Fe, S, Si and O. An optical/UV monitor, co-aligned with the X-ray telescopes and consisting of three separate telescopes, will support the X-ray observations and provide aspect information.

Schnopper, H. W.; Budtz-Jørgensen, C.; Christensen, F. E.; Mewe, R.; Nørgaard-Nielsen, H. U.; Westergaard, N. J.

245

High-Resolution Structure of the Photosynthetic Mn4Ca Catalyst from X-ray Spectroscopy  

SciTech Connect

The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn4Ca cluster, are described. Issues of X-ray damage especially at the metal sites in the Mn4Ca cluster are discussed. The structure of the Mn4Ca catalyst at high-resolution which has so far eluded attempts of determination by X-ray diffraction, EXAFS and other spectroscopic techniques has been addressed using polarized EXAFS techniques applied to oriented PS II membrane preparations and PS II single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and K? emission) have been used earlier to determine the oxidation states of the Mn4Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn4Ca cluster as it cycles through the intermediate S-states.

Yachandra, Vittal; Yano, Junko; Kern, Jan; Pushkar, Yulia; Sauer, Kenneth; Glatzel, Pieter; Bergmann, Uwe; Messinger, Johannes; Zouni, Athina; Yachandra, Vittal K.

2007-08-01

246

Multi-angular regolith effects on planetary soft X-ray fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

Fluorescent X-rays from the surfaces of airless planetary bodies in the inner solar system have been measured by instruments on several spacecraft. MESSENGER carries an X-ray spectrometer (XRS) on-board and has already attempted to obtain fluorescent X-rays from the Hermean surface. BepiColombo will later on carry an X-ray telescope (MIXS-T) along with a more conventional collimating detector (MIXS-C) to the Hermean orbit, supported by a next-generation X-ray solar monitor (SIXS). These instruments will provide unprecedented knowledge about the geochemical properties of the Hermean regolith. X-ray emission from planetary surfaces follows photoionisation by incident solar X-rays and charged particles and reveals information about the elemental composition of the surface. Analyses of X-ray spectra, obtained by orbiting spacecraft, use both the relative intensities of elemental emission lines (e.g., Ca/Si, Fe/Si) and absolute abundancies of the elements to determine the geochemistry of the target body. Historically, the analysis of X-ray spectra has largely assumed that surfaces can be considered as homogeneous plane-parallel media. It has been shown, however, that fluorescent line intensities are affected by the physical properties of the target surface (e.g., surface roughness of the regolith) as a function of the viewing and illumination geometry of observations in a way that cannot be explained by the traditional models. We describe experimental investigations where we simulated the effects of regolith properties on the fluorescent lines measured by an orbiting instrument, with a large variety of illumination and viewing angles. The planetary regolith analogue used in these experiments was a terrestrial, olivine rich basalt, which has been used by previous authors as an analogue to the lunar maria. The basalt samples were ground to powder and sieved to discriminate particles in the ranges, <75 micrometers, 75-250 micrometers, and 250-500 micrometers. These separate powders were then pressed into solid pellets. The separation of particles with different sizes allows some determination of the effects due to changes in, e.g., surface roughness. The pellets were imaged with a CT scanner to obtain the physical parameters of the samples. All measurements were made at near-vacuum pressures to prevent absorption of fluorescent X-rays in air. The relative fluorescent line ratios of several major rock-forming elements (e.g., Si, K, Ca, Ti, Fe) were measured. In addition to experimental studies we have simulated the X-ray emission from a regolith using a numerical Monte-Carlo ray-tracing model. This model simulates a regolith of spherical particles, with defined physical properties (particle size distribution, packing density, etc.) and with a realistic macro-scale surface roughness characteristics generated by constraining the surface with a fractional-Brownian-motion surface model. A comparison is made between the modelling and experimental results to validate the modelling. A good agreement between the results is found. We find that both the measured and the simulated spectra become increasingly hard as the phase angle increases (i.e., X-ray lines at higher energies are enhanced relative to those at lower energies). Some hardening of spectra is predicted by the fundamental parameters equation (FPE) of X-ray fluorescence, which assumes a smooth, flat, and homogeneous surface, but we observe further spectral hardening that is in excess to that predicted by the FPE and that this excess hardening is also a function of the surface roughness. We propose to use modelling similar to ours for the data analysis of soft X-ray fluorescence spectra to take the multi-angular effects related to the physical properties of the regolith into account.

Näränen, J.; Parviainen, H.; Carpenter, J.; Muinonen, K.

2009-04-01

247

X-ray and XUV imaging and spectroscopy of dense plasmas using multilayer optics  

NASA Astrophysics Data System (ADS)

High-reflectance multilayer mirrors and gratings have been developed and implemented in the x-ray and XUV regions. The imaging and spectroscopic instruments have high throughput and can be positioned at a large distance from the radiation source where damage from the plasma debris and the radiation flux does not occur.

Seely, John F.; Brown, C. M.; Kowalski, Michael P.; Cruddace, Raymond G.; Barbee, Troy W.; Hunter, William R.; Rife, Jack C.

1995-09-01

248

Passive Spectroscopy Bolometers, Grating- And X-Ray Imaging Crystal Spectrometers  

SciTech Connect

This tutorial gives a brief introduction into passive spectroscopy and describes the working principles of bolometers, a high-resolution grating spectrometer, and a novel X-ray imaging crystal spectrometer, which is of particular interest for profile measurements of the ion temperature and plasma rotation velocity on ITER and future burning plasma experiments.

Bitter, M; Hill, K W; Scott, S; Paul, S; Ince-Cushmann, A; Reinke, M; Rice, J; Beiersdorfer, P; Gu, M F; Lee, S G; Broennimann, C; Eikenberry, E F

2007-11-07

249

Time-resolved X-ray absorption spectroscopy using an energy dispersive optics: Strengths and limitations  

Microsoft Academic Search

X-ray Absorption Spectroscopy has undergone a great theoretical and experimental development in the last years. This technique has proved to be a powerful tool in elucidating huge number of questions in materials science. Great interest exists in time-resolved experiments achieved with extreme energy resolution and energy scale stability taking full advantage of the strong correlation between the stereochemical environment of

Alouin Fontaine; Elisabeth Dartyge; Jean Itie; Alain Jucha; Alain Polian; Helio Tolentino; Gerard Tourillon

250

Silicon drift detectors for high count rate X-ray spectroscopy at room temperature  

Microsoft Academic Search

Silicon Drift Detectors (SDDs) combine a large sensitive area with a small value of the output capacitance and are therefore well suited for high resolution, high count rate X-ray spectroscopy. The low leakage current level obtained by the elaborated processing technology makes it possible to operate them at room temperature or with moderate cooling. A brief description of the device

P. Lechner; C. Fiorini; R. Hartmann; J. Kemmer; N. Krause; P. Leutenegger; A. Longoni; H. Soltau; D. Stötter; R. Stötter; L. Strüder; U. Weber

2001-01-01

251

Evaluating Superconducting YBCO Film Properties Using X-Ray Photoelectron Spectroscopy (Postprint).  

National Technical Information Service (NTIS)

Initial results have been recently reported that suggest a potential correlation exists between the full-width-half-maximum (FWHM) of the Y(3d) peak obtained by x-ray photoelectron spectroscopy (XPS) and the critical current density a YBa2Cu3O7-x film can...

J. C. Tolliver J. T. Grant P. N. Barnes S. M. Mukhopadhyay T. J. Haugan

2012-01-01

252

Application of x-ray absorption spectroscopy to the study of corrosion and inhibition  

SciTech Connect

X-ray absorption spectroscopy is a powerful technique for determination of valency and coordination. Measurements can be made in air or in situ under electrochemical control. The technique will be described and its application to the analysis of passive oxide films, corrosion products, and inhibitors will be reviewed.

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

1991-01-01

253

Structure of the manganese complex in photosystem II: insights from X-ray spectroscopy.  

PubMed Central

We have used Mn K-edge absorption and Kbeta emission spectroscopy to determine the oxidation states of the Mn complex in the various S states. We have started exploring the new technique of resonant inelastic X-ray scattering spectroscopy; this technique can be characterized as a Raman process that uses K-edge energies (1s to 4p, ca. 6550 eV) to obtain L-edge-like spectra (2p to 3d, ca. 650 eV). The relevance of these data to the oxidation states and structure of the Mn complex is presented. We have obtained extended X-ray absorption fine structure data from the S(0) and S(3) states and observed heterogeneity in the Mn-Mn distances leading us to conclude that there may be three rather than two di-mu-oxo-bridged units present per tetranuclear Mn cluster. In addition, we have obtained data using Ca and Sr X-ray spectroscopy that provide evidence for a heteronuclear Mn-Ca cluster. The possibility of three di-mu-oxo-bridged Mn-Mn moieties and the proximity of Ca is incorporated into developing structural models for the Mn cluster. The involvement of bridging and terminal O ligands of Mn in the mechanism of oxygen evolution is discussed in the context of our X-ray spectroscopy results.

Yachandra, Vittal K

2002-01-01

254

Wettability of Oil-Producing Reservoir Rocks as Determined from X-ray Photoelectron Spectroscopy  

Microsoft Academic Search

Wettability has a dominant effect in oil recovery by waterflooding and in many other processes of industrial and environmental interest. Recently, the suggestion has been made that surface science analytical techniques (SSAT) could be used to rapidly determine the wettability of reservoir materials. Here, we bring the capability of X-ray photoelectron spectroscopy (XPS) to bear on the wettability evaluation of

Pedro G. Toledo; Y. Carolina Araujo; Vladimir Leon

1996-01-01

255

Probing chemical bonding in adsorbates using X-ray emission spectroscopy  

Microsoft Academic Search

When a molecule is adsorbed on a metal surface by chemical bonding new electronic states are formed. The direct observation and identification of these states has been an experimental challenge. Their signature is often obscured by bulk substrate states. In the following contribution we will show how X-ray emission spectroscopy (XES), in spite of its inherent bulk sensitivity, can be

A. Nilsson; J. Hasselström; A. Föhlisch; O. Karis; L. G. M. Pettersson; M. Nyberg; L. Triguero

2000-01-01

256

Combined in situ X-ray diffraction and Raman spectroscopy on majoritic garnet inclusions in diamonds  

Microsoft Academic Search

Mineral inclusions in Sao Luiz diamonds have been characterized using angle dispersive X-ray diffraction and Raman spectroscopy. We identified two different garnet phases coexisting with an omphacitic pyroxene. They represent disintegration products of a former homogeneous majorite-rich garnet phase. The two garnets have significantly different cell parameters but are tightly intergrown with their unit cells parallel to each other. The

Martin Kunz; Philippe Gillet; Guillaume Fiquet; Violaine Sautter; Heinz Graafsma; Pamela Conrad; Jeff Harris

2002-01-01

257

X-ray and Dielectric Spectroscopy Studies Of Chiral Ferroelectric Liquid Crystals With Keto Group  

SciTech Connect

Series of ferroelectric liquid crystals with the keto group attached to the molecule core and one lactate group as the chiral centre have been studied by X-ray and dielectric spectroscopy. The thickness of smectic layers and the average distance between the long axes of neighboring molecules increases with increase of both chains.

Stojanovic, Maja; Obadovic, Dusanka Z. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg D. Obradovica 4, 21000 Novi Sad (Serbia); Bubnov, Alexej; Hamplova, Vera; Kaspar, Miroslav [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic)

2007-04-23

258

Quantitative Characterization of DNA Films by X-ray Photoelectron Spectroscopy.  

National Technical Information Service (NTIS)

We describe the use of self-assembled films of thiolated (dT)25 single-stranded DNA (ssDNA) on gold as a model system for quantitative characterization of DNA films by X-ray photoelectron spectroscopy (XPS). We evaluate the applicability of a uniform and ...

D. Y. Petrovykh H. Kimura-Suda L. J. Whitman M. J. Tarlov

2003-01-01

259

Flat and Spherically Bent Muscovite (Mica) Crystals for X-ray Spectroscopy  

Microsoft Academic Search

Essential parameters for the application of crystals to quantitative X-ray spectroscopy are the upper wavelength limit and the quantitative reflection properties (intrinsic resolving power, luminosity) of the crystal. Due to the large lattice constant, muscovite, a mica group mineral, can be used in the wavelength range up to about 2nm. Muscovite crystals can be bent to small radii of curvature

G. Hölzer; O. Wehrhan; J. Heinisch; E. Förster; T. A. Pikuz; A. Ya Faenov; S. A. Pikuz; V. M. Romanova; T. A. Shelkovenko

1998-01-01

260

X-ray spectroscopy of highly-ionized atoms in an electron beam ion trap (EBIT)  

SciTech Connect

An Electron Beam Ion Trap at Lawrence Livermore National Laboratory is being used to produce and trap very-highly-charged-ions (q /le/ 70+) for x-ray spectroscopy measurements. Recent measurements of dielectronic recombination, electron impact excitation and transition energies are presented. 15 refs., 12 figs., 1 tab.

Marrs, R.E.; Bennett, C.; Chen, M.H.; Cowan, T.; Dietrich, D.; Henderson, J.R.; Knapp, D.A.; Levine, M.A.; Schneider, M.B.; Scofield, J.H.

1988-01-01

261

X-ray spectroscopy of highly-charged heavy ions at FAIR  

Microsoft Academic Search

In the current contribution, we give an overview of the envisioned X-ray spectroscopy program within the atomic physics research collaboration SPARC (Stored Particle Atomic Research Collaboration) at FAIR (Facility for Antiproton and Ion Research). These activities comprise, among others, the investigation of relativistic collision dynamics, electron correlation in the presence of strong fields, the test of Quantum Electrodynamics in extremely

A. Gumberidze; Th. Stöhlker; H. F. Beyer; F. Bosch; A. Bräuning-Demian; S. Hagmann; C. Kozhuharov; Th. Kühl; R. Mann; P. Indelicato; W. Quint; R. Schuch; A. Warczak

2009-01-01

262

X-Ray Photon Correlation Spectroscopy at the European X-Ray Free-Electron Laser (XFEL) facility  

Microsoft Academic Search

The proposed European X-ray Free-Electron Laser source (XFEL) will provide extremely brilliant (B>1033 ph\\/s\\/mm2\\/mrad2\\/0.1% bw) and highly coherent X-ray beams. Due to the pulse structure and the unprecedented brightness one will be able for the first time to study fast dynamics in the time domain, thus giving direct access to the dynamic response function S(Q,t), instead of S(Q,?), which is

Gerhard Grübel

2008-01-01

263

Use of portable X-ray fluorescence instrument for bulk alloy analysis on low corroded indoor bronzes  

NASA Astrophysics Data System (ADS)

One of the most often used non-destructive methods for elemental analysis when performing field measurements on bronze sculptures is X-ray fluorescence (XRF) analysis based on portable instrumentation. However, when performing routine in-situ XRF analysis on corroded objects obtained results are sometimes considerably influenced by the corrosion surface products. In this work the suitability of portable XRF for bulk analysis of low corroded bronzes, which were initially precisely characterized using sophisticated and reliable laboratory methods, was investigated and some improvements in measuring technique and data processing were given. Artificially corroded bronze samples were analyzed by a portable XRF instrument using the same methodology and procedures as when performing in-situ analysis on real objects. The samples were first investigated using sophisticated complementary laboratory techniques: Scanning Electron Microscopy, Proton-Induced X-ray Emission Spectroscopy and Rutherford Backscattering Spectrometry, in order to gain precise information on the formation of the corrosion product layers and in-depth elemental profile of corrosion layers for different aging parameters. It has been shown that for corrosion layers of up to ca. 25 ?m a portable XRF can yield very accurate quantification results.

Šatovi?, D.; Desnica, V.; Fazini?, S.

2013-11-01

264

Experiment investigation of La(1-x)SrxMnO3 by high-resolution X-ray emission and spin-polarized X-ray absorption spectroscopy.  

PubMed

Big changes in resistivity along with the changing of local structure in some oxide systems, such as high-temperature superconductors and colossal magnetoresistance system, strongly suggest the need of a systematic investigation of their local electronic and atomic structures. In this work we present the high-resolution X-ray emission spectra and the spin-polarized X-ray absorption near-edge spectroscopy (SPXANES) data at the Mn K-edge in the La(1-x)Sr(x)MnO(3). This experiment is based on a high-resolution large-acceptance crystal analyzer based on Si (111) and optimized for X-ray fluorescence spectroscopy. With a spherical bent crystal monochromator, a Mn Kbeta emission spectra with high resolution was obtained with a short collection time and SPXANES spectra of La(1-x)Sr(x)MnO(3) at room temperature were also measured at high temperature. PMID:18319193

Hua, Wei; Zhou, Kejin; Huang, Yuying; Qian, Q; He, Wei; Ma, Sixuan; Chu, Wangsheng; Hu, Tiandou; Wu, Ziyu

2008-01-17

265

High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies.  

PubMed

The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0-180 degrees rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/DeltaE is above 33000 at 1 keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 x 10(13) photons s(-1) (0.01% BW)(-1) at 1 keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4 microm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/DeltaE > 11000 at 1 keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given. PMID:20724785

Strocov, V N; Schmitt, T; Flechsig, U; Schmidt, T; Imhof, A; Chen, Q; Raabe, J; Betemps, R; Zimoch, D; Krempasky, J; Wang, X; Grioni, M; Piazzalunga, A; Patthey, L

2010-07-10

266

Resonant soft X-ray emission spectroscopy of liquids  

SciTech Connect

We present now a possible way to carry out soft-x-rayfluorescence spectroscopy of liquids. The liquid cell has a window toattain compatibility with UHV conditions of the spectrometer andbeamline, The synchrotron radiation enters the liquid cell through a 100nm-thick silicon nitride window and the emitted xrays exit through thesame window. This allows in particular liquid solid interfaces to bestudied. Such a liquid cell has been used to study the electronicstructure of a variety of systems ranging from water solutions ofinorganic salts and inertial drugs to nano materials and actinidecompounds in their wet conditions.

Guo, J.-H.; Augustsson, A.; Englund, C.-J.; Nordgren, J.

2004-10-27

267

X-ray spectroscopy of plasmas created by the Nike KrF laser  

SciTech Connect

The x-ray emission from plasmas created by the Naval Research Laboratory Nike KrF laser was characterized using spectroscopic instruments. The targets were thin foils of aluminum and titanium and were irradiated by laser energies in the range 100{endash}1500 J. Using a spherical-crystal imaging spectrometer operating in the 1{endash}2 keV x-ray region, the density, temperature, and opacity of aluminum plasmas were determined with a spatial resolution of 10 {mu}m in the direction perpendicular to the target surface. The spectral line ratios indicated that the aluminum plasmas were relatively dense, cool, and optically thick near the target surface.

Aglitskiy, Y.; Lehecka, T.; Deniz, A.; Hardgrove, J. [Science Applications International Corporation, McLean, Virginia 22102 (United States); Seely, J.; Brown, C.; Feldman, U. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Pawley, C.; Gerber, K.; Bodner, S.; Obenschain, S.; Lehmberg, R.; McLean, E.; Pronko, M.; Sethian, J.; Stamper, J.; Schmitt, A.; Sullivan, C. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Holland, G.; Laming, M. [SFA Inc., 1401 McCormick Drive, Landover, Maryland 20785 (United States)

1997-01-01

268

BeppoSAX spectroscopy of the luminous X-ray sources in M33  

Microsoft Academic Search

The nearby galaxy M33 was observed by the imaging X-ray instruments on-board\\u000aBeppoSAX. Two observations at different phases of the 105.9 day intensity cycle\\u000aof the luminous central source X-8 failed to reveal the expected modulation,\\u000asuggesting that it is probably transitory. Similar behavior has been observed\\u000afrom several X-ray binary sources. This strengthens somewhat the idea that M33\\u000aX-8

A. N. Parmar; L. Sidoli; T. Oosterbroek; P. A. Charles; G. M. B. Dubus; M. Guainazzi; P. Hakala; W. Pietsch; G. Trinchieri

2001-01-01

269

Energy-dispersive X-ray absorption spectroscopy at LNLS: investigation on strongly correlated metal oxides.  

PubMed

An energy-dispersive X-ray absorption spectroscopy beamline mainly dedicated to X-ray magnetic circular dichroism (XMCD) and material science under extreme conditions has been implemented in a bending-magnet port at the Brazilian Synchrotron Light Laboratory. Here the beamline technical characteristics are described, including the most important aspects of the mechanics, optical elements and detection set-up. The beamline performance is then illustrated through two case studies on strongly correlated transition metal oxides: an XMCD insight into the modifications of the magnetic properties of Cr-doped manganites and the structural deformation in nickel perovskites under high applied pressure. PMID:20029117

Cezar, Júlio C; Souza-Neto, Narcizo M; Piamonteze, Cínthia; Tamura, Edilson; Garcia, Flávio; Carvalho, Edson J; Neueschwander, Régis T; Ramos, Aline Y; Tolentino, Hélio C N; Caneiro, Alberto; Massa, Nestor E; Martinez-Lope, Maria Jesus; Alonso, Jose Antonio; Itié, Jean Paul

2009-11-17

270

Testing LaMgAl11O19 crystal for X-ray spectroscopy  

SciTech Connect

We investigated the properties of the rare earth crystal LaMgAl{sub 11}O{sub 19} and its application to soft X-ray spectroscopy. Its relative reflectivity and half width rocking curve were measured to up to the reflection order of 28. In addition, a comparative measurement of the iron L-shell soft X-ray line emission was made on the EBIT-I Livermore electron beam ion trap by fielding the LaMgAl{sub 11}O{sub 19} crystal side by side with a rubidium hydrogen phthalate crystal in a flat crystal spectrometer. From these measurements, reflectivity and spectral resolving power were determined.

Chen, H; Beiersdorfer, P; Baronova, E; Kalashnikova, I; Stepanenko, M

2004-03-31

271

Anodic behaviour and X-ray photoelectron spectroscopy of ternary tin oxides  

Microsoft Academic Search

The compounds SrSnO3, BaSnO3 and Ca2SnO4 have been synthesized by solid-state and\\/or sol–gel methods, characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) and their electrochemical properties studied as cathodes versus Li metal in the range 0.005–1.0V. ASnO3 (A = Sr, Ba), adopt the perovskite structure whereas Ca2SnO4 has the Sr2PbO4 structure. The discharge capacities

N. Sharma; K. M. Shaju; G. V. Subba Rao; B. V. R. Chowdari

2005-01-01

272

Two-dimensional stimulated resonance Raman spectroscopy of molecules with broadband x-ray pulses  

SciTech Connect

Expressions for the two-dimensional stimulated x-ray Raman spectroscopy (2D-SXRS) signal obtained using attosecond x-ray pulses are derived. The 1D- and 2D-SXRS signals are calculated for trans-N-methyl acetamide (NMA) with broad bandwidth (181 as, 14.2 eV FWHM) pulses tuned to the oxygen and nitrogen K-edges. Crosspeaks in 2D signals reveal electronic Franck-Condon overlaps between valence orbitals and relaxed orbitals in the presence of the core-hole.

Biggs, Jason D.; Zhang Yu; Healion, Daniel; Mukamel, Shaul [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States)

2012-05-07

273

High-resolution spectroscopy and high-density monitoring in X-rays of novae  

NASA Astrophysics Data System (ADS)

The 21st century X-ray observatories XMM-Newton, Chandra, and Swift gave us completely new insights into the X-ray behaviour of nova outbursts. These new-generation X-ray observatories provide particularly high spectral resolution and high density in monitoring campaigns, simultaneously in X-rays and UV/optical. The entire evolution of several nova outbursts has been observed with the Swift XRT and UVOT instruments, allowing studies of the gradual shift of the peak of the SED from UV to X-rays, time scales to the onset and duration of the X-ray brightest supersoft source (SSS) phase, and pre- and post-SSS X-ray emission. In addition, XMM-Newton and Chandra observations can efficiently be scheduled, allowing deeper studies of strategically chosen evolutionary stages. Before Swift joined in 2005, Chandra and XMM-Newton blind shots in search of SSS emission unavoidably led to some underexposed observations taken before and/or after the SSS phase. More systematic Swift studies reduced this number while increasing the number of novae. Pre- and post-SSS spectra at low and high spectral resolution were successfully modelled with collisional plasma models. Pre-SSS emission arises in shocks and post-SSS emission in radiatively cooling thin ejecta. In contrast, the grating spectra taken during the SSS phase are a lot more complex than expected and have not yet been successfully modeled. Available hot white dwarf (WD) radiation transport models give only approximate reproduction of the observations, and make some critical assumptions that are only valid in isolated WDs. More grating spectra would be important to search for systematic trends between SSS spectra and system parameters. Summary of well-established discoveries with Swift, XMM-Newton, and Chandra: - About 50% of novae display faint X-ray emission before the start of the SSS phase - The start of the SSS phase is not a smooth process. High-amplitude variations during the early SSS phase were seen that disappear close to the time when the optical plateau phase begins. - The end of the SSS phase is in most cases a smooth process. - The SSS grating spectra contain continuum spectra that roughly resemble a blackbody shape - The SSS X-ray grating spectra of systems with known high inclination angles contain emission lines on top of the continuum - The SSS X-ray spectra of systems with unknown or low inclination angles contain deep absorption lines from the interstellar medium and local, high-ionisation absorption lines that are blue shifted.

Ness, J. U.

2012-09-01

274

Use of Raman spectroscopy in characterizing soft x-ray multilayers: tools in understanding structure and interfaces  

Microsoft Academic Search

Our group is studying the structure and interfaces of soft x-ray multilayers by various techniques including x-ray diffraction and Raman spectroscopy. Raman spectroscopy is particularly useful since it is sensitive to the identity of individual bonds and thus can potentially characterize the abruptness of interfaces in multilayers. Blocking interfacial mixing is very important in achieving and maintaining high reflectivity. We

Ming Cai; Qi Wang; David D. Allred; Larry V. Knight; Dorian M. Hatch; Arturo Reyes-Mena; Guizhong Zhang

1993-01-01

275

Quantification of total element concentrations in soils using total X-ray fluorescence spectroscopy (TXRF).  

PubMed

Total X-ray fluorescence spectroscopy (TXRF) determines concentrations of major and trace elements in multiple media. We developed and tested a method for the use of TXRF for direct quantification of total element concentrations in soils using an S2 PICOFOX™ spectrometer (Bruker AXS Microanalysis GmbH, Germany). We selected 15 contrasting soil samples from across sub-Saharan Africa for element analysis to calibrate the instrument against concentrations determined using the inductively coupled plasma-mass spectroscopy (ICP-MS) standard method. A consistent underestimation of element concentrations using TXRF compared to ICP-MS reference analysis occurred, indicating that spectrometer recalibration was required. Single-element recalibration improved the TXRF spectrometer's sensitivity curve. Subsequent analysis revealed that TXRF determined total element concentrations of Al, K, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Ga accurately (model efficacy/slope close to 1:1 line, and R(2)>0.80) over a wide range of soil samples. Other elements that could be estimated with an acceptable precision (R(2)>0.60) compared with ICP-MS although generally somewhat under- or overestimated were P, Ca, As, Rb, Sr, Y, Pr, Ta and Pb. Even after recalibration, compared to ICP-MS the TXRF spectrometer produced underestimations for elements Na, Mg, Ba, Ce, Hf, La, Nd, W and Sm and overestimations for elements Bi, Tl and Zr. We validated the degree of accuracy of the TXRF analytical method after recalibration using an independent set of 20 soil samples. We also tested the accuracy of the analysis using 2 multi-element standards as well as the method repeatability on replicate samples. The resulting total element concentration repeatability for all elements analyzed were within 10% coefficient of variability after the instrument recalibration except for Cd and Tl. Our findings demonstrate that TXRF could be used as a rapid screening tool for total element concentrations in soils assuming that sufficient calibration measures are followed. PMID:23831788

Towett, Erick K; Shepherd, Keith D; Cadisch, Georg

2013-07-03

276

Two-dimensional microstrip germanium detector for X-ray spectroscopy of highly charged heavy ions  

Microsoft Academic Search

New possibilities are opened utilizing position-sensitive germanium detectors in the X-ray spectroscopy of highly charged heavy ions at GSI-Darmstadt. The recent experiments revealed the need for two-dimensional strip detectors with their inherent advantages concerning spectroscopy and imaging capabilities as well as polarization sensitivity. For the first prototype a germanium diode (70 mm × 41 mm, 11 mm thick) with a

D. Protic; T. Stohlker; T. Krings; I. Mohos; U. Spillmann

2004-01-01

277

Characterization of carbon adsorption to Si(100) surface by thermal desorption spectroscopy and x-ray photoelectron spectroscopy  

Microsoft Academic Search

Carbon adsorption to the Si(100) surface in the atmosphere with large or with small concentrations of organic carbons is examined by using thermal desorption spectroscopy or x-ray photoelectron spectroscopy. The number of carbon atoms on a Si(100) wafer stored in the pure water, in which the total organic carbon is 285 ppb, becomes larger until a certain time with increasing

N. Matsuo; K. Kagawa; T. Miyoshi

1996-01-01

278

Characterization of Delhi iron pillar rust by X-ray diffraction, Fourier transform infrared spectroscopy and Mössbauer spectroscopy  

Microsoft Academic Search

Rust samples obtained from the region just below the decorative bell capital of the Delhi iron pillar (DIP) have been analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mössbauer spectroscopy. The identification of iron hydrogen phosphate hydrate in the crystalline form by XRD was unambiguous. Very weak diffraction from the oxyhydroxides\\/oxides of iron was observed indicating that

R Balasubramaniam; A. V Ramesh Kumar

2000-01-01

279

X-RAY ABSORPTION SPECTROSCOPY OF YB3+-DOPED OPTICAL FIBERS  

SciTech Connect

Optical fibers doped with Ytterbium-3+ have become increasingly common in fiber lasers and amplifiers. Yb-doped fibers provide the capability to produce high power and short pulses at specific wavelengths, resulting in highly effective gain media. However, little is known about the local structure, distribution, and chemical coordination of Yb3+ in the fibers. This information is necessary to improve the manufacturing process and optical qualities of the fibers. Five fibers doped with Yb3+ were studied using Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy and X-ray Absorption Near Edge Spectroscopy (XANES), in addition to Yb3+ mapping. The Yb3+ distribution in each fiber core was mapped with 2D and 1D intensity scans, which measured X-ray fluorescence over the scan areas. Two of the five fibers examined showed highly irregular Yb3+ distributions in the core center. In four of the five fibers Yb3+ was detected outside of the given fiber core dimensions, suggesting possible Yb3+ diffusion from the core, manufacturing error, or both. X-ray absorption spectroscopy (XAS) analysis has so far proven inconclusive, but did show that the fibers had differing EXAFS spectra. The Yb3+ distribution mapping proved highly useful, but additional modeling and examination of fiber preforms must be conducted to improve XAS analysis, which has been shown to have great potential for the study of similar optical fi bers.

Citron, Robert; Kropf, A.J.

2008-01-01

280

X-ray magnetic spectroscopy at high pressure: performance of SPring-8 BL39XU.  

PubMed

An X-ray magnetic circular dichroism experiment under multiple extreme conditions, 2 X-ray beam and a helicity-controlled technique enabled the dichroic signal to be recorded with high accuracy. The performance is shown by the outcome of pressure-induced ferromagnetism in Mn(3)GaC and the pressure-suppressed Co moment in ErCo(2). Two technical developments, a tiny diamond anvil cell inserted into a superconducting magnet and in situ pressure calibration using 90 degrees Bragg diffraction from a NaCl marker, are also presented. X-ray magnetic spectroscopy under multiple extreme conditions is now opening a new approach to materials science. PMID:19844006

Kawamura, Naomi; Ishimatsu, Naoki; Maruyama, Hiroshi

2009-09-15

281

Photodissociation Structural Dynamics of TrirutheniumDodecacarbonyl Investigated by X-ray Transient Absorption Spectroscopy  

NASA Astrophysics Data System (ADS)

The molecular and electronic structures of the transient intermediates generated from the photolysis of trirutheniumdodecacarbonyl, Ru3(CO)12, by ultrafast UV (351 nm) laser excitation were investigated using X-ray transient absorption (XTA) spectroscopy. The electronic configuration change and nuclear rearrangement after the dissociation of carbonyls were observed at ruthenium K-edge X-ray absorption near edge structure and X-ray absorption fine structure spectra. Analysis of XTA data, acquired after 100, 200, and 400 ps and 300 ns time delay following the photoexcitation, identified the presence of three intermediate species with Ru3(CO)10 being the most dominating one. The results set an example of applying XTA in capturing both transient electronic and nuclear configurations in metal clusters simulating catalysts in chemical reactions.

Harpham, Michael R.; Stickrath, Andrew, B.; Zhang, Xiaoyi,; Huang, Jier; Mara, Michael W.; Chen, Lin X.; Liu, Di-Jia

2013-10-01

282

Characterization of surface carbon films on weathered Japaneseroof tiles by soft x-ray spectroscopy  

SciTech Connect

The effects of weathering on carbon films deposited onJapanese smoked roof tileswere investigated by soft x-ray absorption andemission spectroscopy using synchrotron radiation. X-ray absorptionmeasurements revealed that weathering oxidizes the carbon films and thatpartial carboxy chemical bonding occurs. Incident angle-dependent x-rayabsorption spectra in the C K region confirmed that the degree of theorientation at the surface of the oxidized carbon films decreases withweathering. However, the take-off angle-dependent C K x-ray emissionspectra showed that the orientation of the layered carbon structure ismaintained in the bulk portion when weathered. Therefore, it is confirmedthat oxidation proceeds from the surface of the carbon films. Weatheringdegrades and oxidizes the surface carbon films, which causes the metallicsilver color to change to darker gray.

Muramatsu, Y.; Yamashita, M.; Motoyama, M.; Hirose, M.; Denlinger, J.D.; Gullikson, E.M.; Perera, R.C.

2004-07-15

283

Instrumentation for a next-generation x-ray all-sky monitor  

SciTech Connect

We have proposed an x-ray all-sky monitor for a small satellite mission that will be ten times more sensitive than past monitors and that opens up a new band of the soft x-ray spectrum (0.1-3.0 keV) for study. We discuss three approaches to the construction of the optics. The first method, well within the reach of existing technology, is to approximate the lobster-eye geometry by building crossed arrays of planar reflectors, this gives great control over the reflecting surface but is limited in terms of resolution at the baseline 4 arc minute level. The second method is to use microchannel plates; this technology has the potential to greatly exceed the baseline resolution and sensitivity but is yet to be fully demonstrated. The third method, while still in its infancy, may yet prove to be the most powerful; this approach relies on photolithography to expose a substrate that can then be developed and replicated. The scientific case for this mission is almost too broad to state here. The instrument we describe will allow investigation of the long term light curves of thousands of AGN, it will detect thousands of transients, including GRBs and type II supernova, and the stellar coronae of hundreds of the brightest x-ray stars can be monitored. In addition the classical objectives of all-sky monitors--long-term all-sky archive and watchdog alert to new events--will be fulfilled at an unprecedented level. We also note that by opening up a little-explored band of the x-ray sky the opportunity for new discovery is presented. A satisfying example of entering new territory while still retaining the guarantee of expanding the domain of existing research.

Peele, A. G. [Code 662, Laboratory for High Energy Astrophysics, Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)

1999-12-15

284

Applications of Light Element X-ray Raman Spectroscopy and Hard X-ray Emission Spectroscopy to the Electronic Structure of Energy Storage Materials: Prospects and Initial Results from the Spectroscopy Program at SSRL  

NASA Astrophysics Data System (ADS)

We present the applicability of x-ray raman spectroscopy of light elements and hard x-ray emission to probe the electronic structure of energy storage materials under in-situ conditions. In particular, recent advances in resolution and throughput of x-ray raman spectroscopy (XRS) offer the capability to measure 1s x-ray absorption profiles of light elements such as lithium, boron, carbon, nitrogen and oxygen with less than 0.3eV resolution in the order of 10s of minutes. Initial results from the Spectroscopy program at SSRL and collaborations with groups in various energy storage fields will be presented, with an emphasis on Lithium Batteries and Hydrogen Storage applications.

Nordlund, Dennis; Tsu-Chien, Weng; Sokaras, Dimosthenis

2012-02-01

285

An x-ray absorption spectroscopy study of Mo oxidation in Pb at elevated temperatures  

SciTech Connect

The corrosion of fuel cladding and structural materials by lead and lead-bismuth eutectic in the liquid state at elevated temperatures is an issue that must be considered when designing advanced nuclear systems and high-power spallation neutron targets. In this work, lead corrosion studies of molybdenum were performed to investigate the interaction layer as a function of temperature by X-ray absorption spectroscopy. In situ X-ray absorption measurements on a Mo substrate with a 3-6 {micro}m layer of Pb deposited by thermal evaporation were performed at temperatures up to 900 C and at a 15{sup o} angle to the incident X-rays. The changes in the local atomic structure of the corrosion layer are visible in the difference extended X-ray absorption fine structure and the linear combination fitting of the X-ray absorption near-edge structure to as-deposited molybdenum sample and molybdenum oxide (MoO{sub 2} and MoO{sub 3}) standards. The data are consistent with the appearance of MoO{sub 3} in an intermediate temperature range (650-800 C) and the more stable MoO{sub 2} phase dominating at high and low temperatures.

Liu, Shanshan; Olive, Daniel; Terry, Jeff; Segre, Carlo U.; (IIT)

2009-06-30

286

Infrared-x-ray pump-probe spectroscopy of the NO molecule  

SciTech Connect

Two color infrared-x-ray pump-probe spectroscopy of the NO molecule is studied theoretically and numerically in order to obtain a deeper insight of the underlying physics and of the potential of this suggested technology. From the theoretical investigation a number of conclusions could be drawn: It is found that the phase of the infrared field strongly influences the trajectory of the nuclear wave packet, and hence, the x-ray spectrum. The trajectory experiences fast oscillations with the vibrational frequency with a modulation due to the anharmonicity of the potential. The dependences of the x-ray spectra on the delay time, the duration, and the shape of the pulses are studied in detail. It is shown that the x-ray spectrum keep memory about the infrared phase after the pump field left the system. This memory effect is sensitive to the time of switching-off the pump field and the Rabi frequency. The phase effect takes maximum value when the duration of the x-ray pulse is one-fourth of the infrared field period, and can be enhanced by a proper control of the duration and intensity of the pump pulse. The manifestation of the phase is different for oriented and disordered molecules and depends strongly on the intensity of the pump radiation.

Guimaraes, F.F.; Felicissimo, V.C. [Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden); Departamento de Quimica, Universidade Federal de Minas Gerais, Avenida Antonio Carlos, 6627, CEP-31270-901, Belo Horizonte, Minas Gerais (Brazil); Kimberg, V.; Gel'mukhanov, F.; Aagren, H. [Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden); Cesar, A. [Departamento de Quimica, Universidade Federal de Minas Gerais, Avenida Antonio Carlos, 6627, CEP-31270-901, Belo Horizonte, Minas Gerais (Brazil)

2005-07-15

287

Development of a multifunctional surface analysis system based on a nanometer scale scanning electron beam: Combination of ultrahigh vacuum-scanning electron microscopy, scanning reflection electron microscopy, Auger electron spectroscopy, and x-ray photoelectron spectroscopy  

Microsoft Academic Search

We have developed a multifunctional surface analysis system based on a scanning electron beam for nanofabrication and characterization of surface reactions for fabrication processes. The system performs scanning electron microscopy (SEM), scanning reflection electron microscopy (SREM), Auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy. Nanometer scale resolution is obtained for ultrahigh vacuum (UHV)-SEM while the mechanical pumping instruments are operated.

Heiji Watanabe; Masakazu Ichikawa

1996-01-01

288

SURFACE SEGREGATION STUDIES OF SOFC CATHODES: COMBINING SOFT X-RAYS AND ELECTROCHEMICAL IMPEDENCE SPECTROSCOPY  

SciTech Connect

A system to grow heteroepitaxial thin-films of solid oxide fuel cell (SOFC) cathodes on single crystal substrates was developed. The cathode composition investigated was 20% strontium-doped lanthanum manganite (LSM) grown by pulsed laser deposition (PLD) on single crystal (111) yttria-stabilized zirconia (YSZ) substrates. By combining electrochemical impedance spectroscopy (EIS) with x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy XAS measurements, we conclude that electrically driven cation migration away from the two-phase gas-cathode interface results in improved electrochemical performance. Our results provide support to the premise that the removal of surface passivating phases containing Sr2+ and Mn2+, which readily form at elevated temperatures even in O2 atmospheric pressures, is responsible for the improved cathodic performance upon application of a bias.

Miara, Lincoln J.; Piper, L.F.J.; Davis, Jacob N.; Saraf, Laxmikant V.; Kaspar, Tiffany C.; Basu, Soumendra; Smith, K. E.; Pal, Uday B.; Gopalan, Srikanth

2010-12-01

289

High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies  

Microsoft Academic Search

We describe the concepts and technical realization of the high-resolution\\u000asoft-X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV\\u000aand intended for Resonant Inelastic X-ray Scattering (RIXS) and Angle-Resolved\\u000aPhotoelectron Spectroscopy (ARPES). The photon source is an undulator of novel\\u000afixed-gap design where longitudinal movement of permanent magnetic arrays\\u000acontrols not only the light polarization (including

V. N. Strocov; T. Schmitt; U. Flechsig; T. Schmidt; A. Imhof; Q. Chen; J. Raabe; R. Betemps; D. Zimoch; J. Krempasky; X. Wang; M. Grioni; A. Piazzalunga; L. Patthey

2010-01-01

290

X-ray analysis and mapping by wavelength dispersive X-ray spectroscopy in an electron microscope  

Microsoft Academic Search

A compact and easy-to-use wavelength dispersive X-ray spectrometer using a multi-capillary X-ray lens attached to a scanning (transmission) electron microscope has been tested for thin-film analysis. B–K spectra from thin-film boron compounds (B4C, h-BN, and B2O3) samples showed prominent peak shifts and detailed structural differences. Mapping images of a thin W\\/Si double-layer sample resolved each element clearly. Additionally, a thin

Miyoko Tanaka; Masaki Takeguchi; Kazuo Furuya

2008-01-01

291

Soft X-ray synchrotron radiation investigations of actinidematerials systems utilizing X-ray emission spectroscopy and resonantinelastic X-ray scattering  

Microsoft Academic Search

Synchrotron radiation (SR) methods have been utilized with increasing frequency over the past several years to study topics in actinide science, ranging from those of a fundamental nature to those that address a specifically-targeted technical need. In particular, the emergence of microspectroscopic and fluorescence-based techniques have permitted investigations of actinide materials at sources of soft x-ray SR. Spectroscopic techniques with

D. K. Shuh; S. M. Butorin; J.-H. Guo; J. Nordgren

2004-01-01

292

Characterization of an Yb:LuVO 4 single crystal using X-ray topography, high-resolution X-ray diffraction, and X-ray photoelectron spectroscopy  

Microsoft Academic Search

Knowledge on the defect and electronic structure allows for improved modeling of material properties. A short literature review has shown that the information on defect structure of rare earth orthovanadate single crystals is limited. In this paper, defect and electronic structure of a needle-shaped Yb:LuVO4 single crystal grown by the slow cooling method have been studied by means of X-ray

W. Paszkowicz; P. Romanowski; J. Bak-Misiuk; W. Wierzchowski; K. Wieteska; W. Graeff; R. J. Iwanowski; M. H. Heinonen; O. Ermakova; H. Dabkowska

2011-01-01

293

X-Ray Chemical Analysis of Multilayered Thin Films by Scanning Electron Microscopy and Total-Reflection-Angle X-Ray Spectroscopy  

NASA Astrophysics Data System (ADS)

Scanning electron microscopy and total-reflection-angle X-ray spectroscopy (SEM-TRAXS) have been applied to X-ray chemical analysis of multilayered thin films on Si substrates. Clear differences were observed in the take-off angle (? t) dependence of the X-ray intensities between Pd(10 nm)/Au(10 nm)/Si and Au(10 nm)/Pd(10 nm)/Si structures. The ? t dependence varied with layer thickness increase from 10 to 13 nm. An AlN(30 nm)/Al2O3(30 nm)/Si structure was also successfully analyzed by measuring the ? t dependence of NK ?, OK ?, AlK ? and SiK ? lines.

Yonemitsu, Kyoko; Shibata, Noriyoshi

1994-06-01

294

Quick extended x-ray absorption fine structure instrument with millisecond time scale, optimized for in situ applications  

NASA Astrophysics Data System (ADS)

In order to learn about in situ structural changes in materials at subseconds time scale, we have further refined the techniques of quick extended x-ray absorption fine structure (QEXAFS) and quick x-ray absorption near edge structure (XANES) spectroscopies at beamline X18B at the National Synchrotron Light Source. The channel cut Si (111) monochromator oscillation is driven through a tangential arm at 5 Hz, using a cam, dc motor, pulley, and belt system. The rubber belt between the motor and the cam damps the mechanical noise. EXAFS scan taken in 100 ms is comparable to standard data. The angle and the angular range of the monochromator can be changed to collect a full EXAFS or XANES spectrum in the energy range 4.7-40.0 KeV. The data are recorded in ascending and descending order of energy, on the fly, without any loss of beam time. The QEXAFS mechanical system is outside the vacuum system, and therefore changing the mode of operation from conventional to QEXAFS takes only a few minutes. This instrument allows the acquisition of time resolved data in a variety of systems relevant to electrochemical, photochemical, catalytic, materials, and environmental sciences.

Khalid, S.; Caliebe, W.; Siddons, P.; So, I.; Clay, B.; Lenhard, T.; Hanson, J.; Wang, Q.; Frenkel, A. I.; Marinkovic, N.; Hould, N.; Ginder-Vogel, M.; Landrot, G. L.; Sparks, D. L.; Ganjoo, A.

2010-01-01

295

Quick extended x-ray absorption fine structure instrument with millisecond time scale, optimized for in situ applications  

SciTech Connect

In order to learn about in situ structural changes in materials at subseconds time scale, we have further refined the techniques of quick extended x-ray absorption fine structure (QEXAFS) and quick x-ray absorption near edge structure (XANES) spectroscopies at beamline X18B at the National Synchrotron Light Source. The channel cut Si (111) monochromator oscillation is driven through a tangential arm at 5 Hz, using a cam, dc motor, pulley, and belt system. The rubber belt between the motor and the cam damps the mechanical noise. EXAFS scan taken in 100 ms is comparable to standard data. The angle and the angular range of the monochromator can be changed to collect a full EXAFS or XANES spectrum in the energy range 4.7-40.0 KeV. The data are recorded in ascending and descending order of energy, on the fly, without any loss of beam time. The QEXAFS mechanical system is outside the vacuum system, and therefore changing the mode of operation from conventional to QEXAFS takes only a few minutes. This instrument allows the acquisition of time resolved data in a variety of systems relevant to electrochemical, photochemical, catalytic, materials, and environmental sciences.

Khalid, S.; Caliebe, W.; Siddons, P.; So, I.; Clay, b.; Hanson, J.; Wang, Q.; Frenkel, A.; Marinkovicl, N.; Hould, N.; ginder-Vogel, M.; Landrot, G.L.; Sparks, D.L.; Ganjoo, A.

2010-01-19

296

High resolution x-ray fluorescence spectroscopy - a new technique for site- and spin-selectivity  

SciTech Connect

X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has been developed. By high resolution fluorescence detection, the chemical sensitivity of K emission spectra can be used to identify oxidation and spin states; it can also be used to facilitate site-selective X-ray Absorption Near Edge Structure (XANES) and site-selective Extended X-ray Absorption Fine Structure (EXAFS). The spin polarization in K fluorescence could be used to generate spin selective XANES or spin-polarized EXAFS, which provides a new measure of the spin density, or the nature of magnetic neighboring atoms. Finally, dramatic line-sharpening effects by the combination of absorption and emission processes allow observation of structure that is normally unobservable. All these unique characters can enormously simplify a complex x-ray spectrum. Applications of this novel technique have generated information from various transition-metal model compounds to metalloproteins. The absorption and emission spectra by high resolution fluorescence detection are interdependent. The ligand field multiplet model has been used for the analysis of K{alpha} and K{beta} emission spectra. First demonstration on different chemical states of Fe compounds has shown the applicability of site selectivity and spin polarization. Different interatomic distances of the same element in different chemical forms have been detected using site-selective EXAFS.

Wang, Xin [Univ. of California, Davis, CA (United States). Dept. of Applied Science]|[Lawrence Berkeley National Lab., CA (United States)

1996-12-01

297

Structure of the Mn complex in photosystem II: Insights from x-ray spectroscopy  

SciTech Connect

We have used Mn K-edge absorption and Kb emission spectroscopies to determine the oxidation states of the Mn complex in the various S-states. We have started exploring the new technique of resonant inelastic X-ray scattering spectroscopy (RIXS); this technique can be characterized as a Raman process that uses K-edge energies (1s to 4p, {approx}6550 eV) to obtain L-edge-like spectra (2p to 3d, {approx}650 eV). The relevance of these data to the oxidation states and structure of the Mn complex is presented. We have obtained EXAFS data from the S0 and S3 states and observed heterogeneity in the Mn-Mn distances, leading us to conclude that there may be three rather than two di-(mu)-oxo bridged units present per tetranuclear Mn cluster. In addition, we have obtained data using Ca/Sr X-ray spectroscopy that provide evidence for a heteronuclear Mn/Ca cluster. The possibility of three di-(mu)-oxo-bridged Mn Mn moieties and the proximity of Ca is incorporated into developing structural models for the Mn cluster. The involvement of bridging and terminal O ligands of Mn in the mechanism of oxygen evolution is discussed in the context of our X-ray spectroscopy results.

Yachandra, Vittal K.

2002-04-02

298

X-ray photo-emission and energy dispersive spectroscopy of HA coated titanium  

SciTech Connect

The purpose of this study was to determine the chemical composition changes of hydroxyapatite (HA) coated titanium using surface analysis (x-ray photo-emission) and bulk analysis (energy dispersive spectroscopy). The specimens examined were controls, 30 minutes and 3 hours aged specimens in distilled water or 0.2M sodium phosphate buffer (pH 7.2) at room temperature. Each x-ray photo-emission cycle consisted of 3 scans followed by argon sputtering for 10 minutes for a total of usually 20 cycles, corresponding to a sampling depth of {approximately} 1500 {angstrom}. The energy dispersive spectroscopy analysis was on a 110 by 90 {mu}m area for 500 sec. Scanning electron microscopy examination showed crystal formation (3P{sub 2}O{sub 5}*2CAO*?H{sub 2}O by energy dispersive spectroscopy analysis) on the HA coating for the specimens aged in sodium phosphate buffer. The x-ray photo-emission results indicated the oxidation effect of water on the titanium (as TiO{sub 2}) and the effect of the buffer to increase the surface concentration of phosphorous. No differences in the chemical composition were observed by energy dispersive spectroscopy analysis. The crystal growth was only observed for the sodium phosphate buffer specimens and only on the HA surface.

Drummond, J.L.; Steinberg, A.D. [Univ. of Illinois, Chicago, IL (United States); Krauss, A.R. [Argonne National Lab., IL (United States)] [and others

1997-08-01

299

X-ray and photoelectron spectroscopy of the structure, reactivity, and electronic structure of semiconductor nanocrystals  

SciTech Connect

Semiconductor nanocrystals are a system which has been the focus of interest due to their size dependent properties and their possible use in technological applications. Many chemical and physical properties vary systematically with the size of the nanocrystal and thus their study enables the investigation of scaling laws. Due to the increasing surface to volume ratio as size is decreased, the surfaces of nanocrystals are expected to have a large influence on their electronic, thermodynamic, and chemical behavior. In spite of their importance, nanocrystal surfaces are still relatively uncharacterized in terms of their structure, electronic properties, bonding, and reactivity. Investigation of nanocrystal surfaces is currently limited by what techniques to use, and which methods are suitable for nanocrystals is still being determined. This work presents experiments using x-ray and electronic spectroscopies to explore the structure, reactivity, and electronic properties of semiconductor (CdSe, InAs) nanocrystals and how they vary with size. Specifically, x-ray absorption near edge spectroscopy (XANES) in conjunction with multiple scattering simulations affords information about the structural disorder present at the surface of the nanocrystal. X-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS) probe the electronic structure in terms of hole screening, and also give information about band lineups when the nanocrystal is placed in electric contact with a substrate. XPS of the core levels of the nanocrystal as a function of photo-oxidation time yields kinetic data on the oxidation reaction occurring at the surface of the nanocrystal.

Hamad, K.S.

2000-05-01

300

Pixellated Cd(Zn)Te high-energy X-ray instrument  

PubMed Central

We have developed a pixellated high energy X-ray detector instrument to be used in a variety of imaging applications. The instrument consists of either a Cadmium Zinc Telluride or Cadmium Telluride (Cd(Zn)Te) detector bump-bonded to a large area ASIC and packaged with a high performance data acquisition system. The 80 by 80 pixels each of 250 ?m by 250 ?m give better than 1 keV FWHM energy resolution at 59.5 keV and 1.5 keV FWHM at 141 keV, at the same time providing a high speed imaging performance. This system uses a relatively simple wire-bonded interconnection scheme but this is being upgraded to allow multiple modules to be used with very small dead space. The readout system and the novel interconnect technology is described and how the system is performing in several target applications.

Seller, P.; Bell, S.; Cernik, R.J.; Christodoulou, C.; Egan, C.K.; Gaskin, J.A.; Jacques, S.; Pani, S.; Ramsey, B.D.; Reid, C.; Sellin, P.J.; Scuffham, J.W.; Speller, R.D.; Wilson, M.D.; Veale, M.C.

2012-01-01

301

Algorithms for a hand-held miniature x-ray fluorescence analytical instrument  

SciTech Connect

The purpose of this joint program was to provide technical assistance with the development of a Miniature X-ray Fluorescence (XRF) Analytical Instrument. This new XRF instrument is designed to overcome the weaknesses of spectrometers commercially available at the present time. Currently available XRF spectrometers (for a complete list see reference 1) convert spectral information to sample composition using the influence coefficients technique or the fundamental parameters method. They require either a standard sample with composition relatively close to the unknown or a detailed knowledge of the sample matrix. They also require a highly-trained operator and the results often depend on the capabilities of the operator. In addition, almost all existing field-portable, hand-held instruments use radioactive sources for excitation. Regulatory limits on such sources restrict them such that they can only provide relatively weak excitation. This limits all current hand-held XRF instruments to poor detection limits and/or long data collection times, in addition to the licensing requirements and disposal problems for radioactive sources. The new XRF instrument was developed jointly by Quantrad Sensor, Inc., the Naval Research Laboratory (NRL), and the Department of Energy (DOE). This report describes the analysis algorithms developed by NRL for the new instrument and the software which embodies them.

Elam, W.T.; Newman, D.; Ziemba, F. [and others

1998-12-31

302

EUV, X-ray, and gamma-ray instrumentation for astronomy III; Proceedings of the Meeting, San Diego, CA, July 22-24, 1992  

NASA Astrophysics Data System (ADS)

The present conference discusses the optimization of Nb tunnel junctions as X-ray detectors, superconducting tunnel junctions for X-ray spectroscopy, diffuse X-ray spectrometer experiment, a microstrip proportional counter, the X-ray performance of an imaging gas-scintillation proportional counter, and X-ray imaging with the XSPECT/SODART microstrip proportional counters. Also discussed are radiation-entrance windows for CCD detectors, detection of X-rays with an optical imaging chamber, ultrahigh-resolution photon-counting system, an X-ray detector using superconducting Al tunnel junctions, the performance and limitations of thermal detectors for X-ray astronomy, imaging solar flares in hard X-rays using Fourier telescopes, and a modular rotating collimator imaging X-ray spectrometer. (For individual items see A93-29477 to A93-29527)

Siegmund, Oswald H. W.

1992-10-01

303

Toward Femtosecond X-ray Spectroscopy at the Advanced Light Source  

SciTech Connect

The realization of tunable, ultrashort pulse x-ray sources promises to open new venues of science and to shed new light on long-standing problems in condensed matter physics and chemistry. Fundamentally new information can now be accessed. Used in a pump-probe spectroscopy, ultrashort x-ray pulses provide a means to monitor atomic rearrangement and changes in electronic structure in condensed-matter and chemical systems on the physically-limiting time-scales of atomic motion. This opens the way for the study of fast structural dynamics and the role they play in phase transitions, chemical reactions and the emergence of exotic properties in materials with strongly interacting degrees of freedom. The ultrashort pulse x-ray source developed at the Advanced Light Source at the Lawrence Berkeley Laboratory is based on electron slicing in storage rings, and generates {approx}100 femtosecond pulses of synchrotron radiation spanning wavelengths from the far-infrared to the hard x-ray region of the electromagnetic spectrum. The tunability of the source allows for the adaptation of a broad range of static x-ray spectroscopies to useful pump-probe measurements. Initial experiments are attempted on transition metal complexes that exhibit relatively large structural changes upon photo-excitation and which have excited-state evolution determined by strongly interacting structural, electronic and magnetic degrees of freedom. Specifically, iron(II) complexes undergo a spin-crossover transition upon optical irradiation. The dynamics of the transition involve a metal-to-ligand charge transfer, a {Delta}S=2 change in magnetic moment and 10% bond dilation in the first coordination shell of the iron. Studies of the electronic dynamics are studied with time-resolved optical absorption measurements. The current progress of time-resolved structural studies to complete the picture of the spin-crossover transition is presented.

Chong, Henry Herng Wei

2004-04-16

304

Ultrafast X-ray spectroscopy as a probe of nonequilibrium dynamics in ruthenium complexes  

NASA Astrophysics Data System (ADS)

The ultrafast intersystem crossing in ruthenium complexes between the singlet and triplet metal-to-ligand charge-transfer states following photoexcitation is described. The absence of a clear decay mechanism between these states makes it difficult to explain this process within a conventional framework using rate equations based on Fermi's golden rule. We show that the decay can be mediated by metal-centered (MC) triplet states leading to decay times of the order of several tens of femtoseconds. The calculated stable excited state probability is dominated by the 3MLCT configuration. The detailed nature of this process is clearly reflected in the calculated spectral lineshapes of the time-dependent nonequilibrium X-ray absorption spectroscopy that show a transient crystal-field collapse, dynamic broadenings, and changes in the branching ratio. We demonstrate that ultrafast X-ray spectroscopy is a suitable probe to deliver detailed new insights or discriminate between competing physical scenarios.

Chang, Jun; Fedro, A. J.; van Veenendaal, Michel

2012-10-01

305

The hydrogen bond of water from the perspective of soft X-ray spectroscopy.  

PubMed

Its importance for life and its unusual properties keep water within the focus of ongoing research; this focus especially applies to water in the liquid phase. Scientists agree that the hydrogen-bond network, which is formed by interactions between the water molecules, is key for understanding the anomalies of water. However, a better understanding of the structure of this network, as well as its dynamics, must yet be established. Soft X-ray spectroscopy allows the investigation of the local electronic structure of water by probing the occupied and unoccupied valence molecular orbitals. In this Focus Review, we present soft-X-ray-based techniques, their development in terms of liquid spectroscopy, and recent studies on the hydrogen-bond network of liquid water. PMID:22945810

Lange, Kathrin M; Aziz, Emad F

2012-09-04

306

X-ray reflectivity and photoelectron spectroscopy study of interdiffusion at the Si/Fe interface  

NASA Astrophysics Data System (ADS)

We have investigated the nature of silicon on iron interface in electron beam deposited Fe/Si bilayers, with various iron and silicon thicknesses. The Fe and Si layer thicknesses are varied from 30 to 330 A? and 20 to 86 A?, respectively. Grazing incidence x-ray reflectivity and photoelectron spectroscopy measurements were carried out on these samples to determine interface characteristics. Si on Fe (Si_Fe) interlayer thickness, roughness, and composition do not depend on the thickness of Fe and Si. The thickness of the interlayer is around 13 A?. A systematic variation in silicide concentration across this interface is observed by x-ray photoelectron spectroscopy measurement. Change in the density of states in valence band across this interface is also observed by ultraviolet photoelectron measurement.

Naik, S. R.; Rai, S.; Lodha, G. S.; Brajpuriya, R.

2006-07-01

307

Spatial high resolution energy dispersive X-ray spectroscopy on thin lamellas.  

PubMed

For conventional samples and measurement geometries the spatial resolution of energy dispersive X-ray spectroscopy is limited by a tear drop shaped emission volume to about 1 ?m. This restriction can be substantially improved using thin samples and high acceleration voltage. In this contribution the spatial resolution of energy dispersive X-ray spectroscopy in a scanning electron microscope using thin lamella samples is investigated. At an acceleration voltage of 30 kV, an edge resolution down to ?dedge = 40 ± 10 nm is observed performing linescans across an interface, using an 80 nm thin sample prepared from a GaAs/AlAs-heterostructure. Furthermore, Monte-Carlo simulations of pure elements ranging from sodium to mercury are performed for different sample thicknesses. From the simulations we can derive a simple empirical formula to predict the spatial resolution as a function of sample thickness. PMID:23545434

Notthoff, Christian; Winterer, Markus; Beckel, Andreas; Geller, Martin; Heindl, Jürgen

2013-02-18

308

Energy Dispersive X-Ray Absorption Spectroscopy: Beamline Results and Opportunities  

NASA Astrophysics Data System (ADS)

ID24 is the energy dispersive beamline of the European Synchrotron Radiation Facility dedicated to X-ray Absorption Spectroscopy (XAS). Since 2000, a complete refurbishment program has started, including source upgrade, mirrors replacement, polychromator optimization and detection improvements. These have made possible the development of new applications in a variety of different fields, ranging from the measurement of tiny atom displacements to time resolved techniques, from measurements under extreme conditions to micro-XAS studies.

Mathon, O.; Aquilanti, G.; Guilera, G.; Muñoz, M.; Newton, M. A.; Trapananti, A.; Pascarelli, S.

2007-01-01

309

X-ray photoelectron spectroscopy analysis of bulk Pd-Ni-P metallic glasses  

Microsoft Academic Search

The core-level and valence-band spectra were obtained from high-resolution X-ray photoelectron spectroscopy of the bulk glassy and crystalline PdxNi80-xP20 (x = 20-70) alloys. Upon crystallization of glassy Pd40Ni40P20, which exhibits the highest glass stability, a small change in chemical bonding is observed. This appears as a charge transfer from P atoms to Ni and Pd atoms. The level of chemical

F. M. Alamgir; H. Jain; A. C. Miller; D. B. Williams; R. B. Schwarz

1999-01-01

310

X-ray photoelectron spectroscopy of fluorescein adsorbed on model solar-cell surfaces  

Microsoft Academic Search

We report on the X-ray photoelectron spectroscopy of fluorescein molecules adsorbed under UHV conditions on single crystal rutile TiO2(110) and Au\\/TiO2(110) surfaces. The molecule is thought to bond covalently to these model solar-cell surfaces primarily through the deprotonated carboxylic group, with an additional interaction arising between the triple ring structure of the molecule and the surface.

James N O’Shea; J Ben Taylor; Emily F Smith

2004-01-01

311

Calibration of paint and varnish properties: Potentialities using X-ray Spectroscopy and Partial Least Squares  

Microsoft Academic Search

This work presents a method for multivariate calibration of the properties of varnishes and paints, combining X-ray Spectroscopy (XRS) with Partial Least Squares (PLS) data treatment. The potential calibrated property for varnishes was density (calibrated values raging from 0.88 to 0.92 g cm?3 and absolute errors from 0.0014 to 0.055 g cm?3). For paints, the potential calibrated property was Stormer viscosity (calibrated

Fabíola Manhas Verbi Pereira; Maria Izabel Maretti Silveira Bueno

2008-01-01

312

Characterisation of the passive film on HIPed Stellite 6 alloy using X-ray photoelectron spectroscopy  

Microsoft Academic Search

In this paper results from the X-ray photoelectron spectroscopy (XPS) analysis of hot isostatically pressed (HIP) Stellite 6 in a 3.5% NaCl liquid medium are reported. The aim of the paper is to determine the composition of the passive film formed at different temperatures and link it to the corrosion properties. It has been shown that the alloy passivates spontaneously

U. Malayoglu; A. Neville; G. Beamson

2005-01-01

313

X-Ray photon correlation spectroscopy study of Brownian motion of gold colloids in glycerol  

SciTech Connect

We report x-ray photon correlation spectroscopy studies of the static structure factor and dynamic correlation function of a gold colloid dispersed in the viscous liquid glycerol. We find a diffusion coefficient for Brownian motion of the gold colloid which agrees well with that extrapolated from measurements made with visible light, but which was determined on an optically opaque sample and in a wave-vector range inaccessible to visible light.

Dierker, S.B.; Pindak, R.; Fleming, R.M.; Robinson, I.K.; Berman, L. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1120 (United States)]|[AT& T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974-0636 (United States)]|[Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3080 (United States)]|[National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

1995-07-17

314

Magnetism in FeO at Megabar Pressures from X-Ray Emission Spectroscopy  

Microsoft Academic Search

We report evidence for a preserved magnetic state in FeO up to 143 GPa at room temperature using high-resolution x-ray emission spectroscopy. This observation is based on the spectral line shape of the Fe Kbeta emission line. Up to the highest pressure, FeO remains a magnetic insulator. Combining our results with previous Mössbauer data, we present a new magnetic phase

James Badro; Viktor V. Struzhkin; Jinfu Shu; Russell J. Hemley; Ho-Kwang Mao; Chi-Chang Kao; Jean-Pascal Rueff; Guoyin Shen

1999-01-01

315

High-pressure phase transition in gallium phosphide: An x-ray-absorption spectroscopy study  

Microsoft Academic Search

High-pressure behavior of GaP has been studied by x-ray-absorption spectroscopy in a diamond-anvil cell up to 36 GPa. The room-temperature equation of state of phase I has been determined. The transition from a fourfold (zinc-blende) to a sixfold (beta-tin) coordination scheme is observed near 26 GPa. Analysis of the data obtained on a sample quickly depressurized from 36 GPa shows

J. P. Itie; A. Polian; C. Jauberthie-Carillon; E. Dartyge; A. Fontaine; H. Tolentino; G. Tourillon

1989-01-01

316

X-ray absorption spectroscopy beyond the core-hole lifetime  

SciTech Connect

A new technique to overcome the core-hole lifetime broadening in x-ray absorption spectroscopy is presented. It utilizes a high resolution fluorescence spectrometer which can be used to analyze the fluorescence photon energy with better resolution than the natural lifetime width. Furthermore, the high resolution spectrometer can also be used to select the final state in the fluorescence process which can offer spin selectivity even without long range magnetic order in the sample.

Haemaelaeinen, K.; Hastings, J.B.; Siddons, D.P.; Berman, L.

1992-10-01

317

X-ray absorption spectroscopy beyond the core-hole lifetime  

SciTech Connect

A new technique to overcome the core-hole lifetime broadening in x-ray absorption spectroscopy is presented. It utilizes a high resolution fluorescence spectrometer which can be used to analyze the fluorescence photon energy with better resolution than the natural lifetime width. Furthermore, the high resolution spectrometer can also be used to select the final state in the fluorescence process which can offer spin selectivity even without long range magnetic order in the sample.

Haemaelaeinen, K.; Hastings, J.B.; Siddons, D.P.; Berman, L.

1992-01-01

318

X-ray photoelectron spectroscopy of uv laser irradiated sapphire and alumina  

Microsoft Academic Search

X-ray photoelectron spectroscopy (XPS) was performed on as-received, annealed, and laser-irradiated sapphire and alumina in order to study effects of different treatments on surface chemistry and properties. Laser irradiations at 308 nm were performed in air and in a reducing atmosphere (Ar-4% hydrogen). Atomic percentages of carbon, aluminum, and oxygen were measured in all specimens;particular attention was paid to percentages

A. J. Pedraza; J. W. Park; H. M. Meyer; D. N. Braski

1994-01-01

319

Thermal stability and surface modifications of detonation diamond nanoparticles studied with X-ray photoelectron spectroscopy  

Microsoft Academic Search

Detonation nanodiamond (ND) particles were dispersed on silicon nitride (SiNx) coated sc-Si substrates by spin-coating technique. Their surface density was in the 1010–1011cm?2 range. Thermal stability and surface modifications of ND particles were studied by combined use of X-ray Photoelectron Spectroscopy (XPS) and Field Emission Gun Scanning Electron Microscopy (FEG SEM). Different oxygen-containing functional groups could be identified by XPS

S. Zeppilli; J. C. Arnault; C. Gesset; P. Bergonzo; R. Polini

2010-01-01

320

Development of multilayer coated gratings for high-energy x-ray spectroscopy  

Microsoft Academic Search

The multilayer coated grating for high energy x-ray spectroscopy above 6 keV was developed. We study the grating optics for high energy region using multilayer. We coated the laminar type grating, groove density\\/mm and depth of groove is 40 nm, with Pt\\/C multilayer, number of layer pairs is 10 and periodic length is 4.8 nm. We measured this gratings using

Keisuke Tamura; Koujun Yamashita; Hideyo Kunieda; Tsutomu Yoshioka; Manabu Watanabe; Kazutoshi Haga

1999-01-01

321

New results with semiconductor drift chambers for x-ray spectroscopy  

SciTech Connect

Silicon Drift Detectors have been tested for X-ray Spectroscopy applications. By optimizing the detector-FET connection and using a very low leakage current detector manufacturing process, it has been possible to achieve a very good energy resolution. The resolution and leakage current have been studies as a function of temperature, from room temperature down to [minus]30 C, and as a function of active area. Also the effects influencing the peak to background ratio have been outlined.

Jalas, P.; Niemelae, A. (Outokumpu Instruments Oy, Espoo (Finland)); Chen, W.; Rehak, P. (Brookhaven National Lab., Upton, NY (United States)); Castoldi, A.; Longoni, A. (Politecnico di Milano (Italy))

1994-08-01

322

The X-ray photoelectron spectroscopy of surface composition of aged mixed copper manganese oxide catalysts  

Microsoft Academic Search

A series of copper manganese oxide catalysts of approximate composition Cu1+xMn2?xO4 (x = 0.54 ± 0.04), which was aged at various times and at different pH values, has been studied by X-ray photoelectron spectroscopy (XPS). In all cases, copper (II) and manganese (IV) are the only oxidation states. The copper\\/manganese concentration ratio exceeds the bulk value (0.5) at short ageing

Ali Akbar Mirzaei; Hamid Reza Shaterian; Massoud Kaykhaii

2005-01-01

323

Repair of fractured framework: scanning electron microscopy and energy dispersive X-ray spectroscopy.  

PubMed

Fractured metal prostheses can be analyzed for possible causes of failure using scanning electron microscopy (SEM). In this study, fractography is used to determine the cause of the failure and whether repair is practical. Energy-dispersive x-ray spectroscopy (EDS) is used to determine composition of the fractured prosthesis so that a repair process can be recommended. The technique is presented for the repair of a titanium framework for an implant-supported overdenture based on the analysis data. PMID:15359153

Maalhagh-Fard, Ahmad; Wagner, Warren C

2004-09-01

324

X-ray photoemission spectroscopy study of fluorinated single-walled carbon nanotubes  

Microsoft Academic Search

We have investigated the change of atomic and electronic structures of fluorinated single-walled carbon nanotubes (SWCNTs) using x-ray photoemission spectroscopy (XPS), electrical resistivity measurements, and transmission electron microscopy (TEM). The fluorine content increases with increasing reaction temperature up to 300 °C. XPS indicated that the fluorinated SWCNT reveals an ionic-bonding character at low concentration and covalent-bonding character at high concentration.

Kay Hyeok An; Jeong Goo Heo; Kwan Goo Jeon; Dong Jae Bae; Chulsu Jo; Cheol Woong Yang; Chong-Yun Park; Young Hee Lee; Young Seak Lee; Young Su Chung

2002-01-01

325

Characterization of coprecipitated nickel on silica methanation catalysts by x-ray photoelectron spectroscopy  

Microsoft Academic Search

An x-ray photoemission spectroscopy study of a series of standard nickel compounds (Ni, NiO, Ni(OH)â, NiSiOâ) and silica-supported nickel methanation catalysts has been conducted. The binding energies and spectral shapes of the standard samples provide a data base which has been used to understand the catalyst spectra. The activity and thermal stability of coprecipitated nickel catalysts has been attributed to

R. B. Shalvoy; P. J. Reucroft; B. H. Davis

1979-01-01

326

XPS: a multi-channel preamplifier-shaper IC for X-ray spectroscopy  

Microsoft Academic Search

An integrated circuit featuring 48 channels of charge sensitive preamplifiers followed by variable-gain pulse shaping amplifiers is being developed as part of an X-ray spectrometer with a highly segmented detector to handle high fluxes in synchrotron experiments. Such detector systems can provide excellent energy resolution combined with one-dimensional spatial information. The IC combines many basic spectroscopy amplifier functions with a

B. Krieger; I. Kipnis; B. A. Ludewigt

1998-01-01

327

Characterisation of crystalline CSH phases by X-ray photoelectron spectroscopy  

Microsoft Academic Search

We have prepared a number of crystalline calcium-silicate-hydrate (C-S-H) phases hydrothermally, with calcium–silicon ratios varying from approximately 0.5 (K-phase) to 2.0 (hillebrandite and ?-dicalcium silicate hydrate). The phases were then analysed using X-ray photoelectron spectroscopy (XPS). Increasing calcium–silicon ratios resulted in decreased silicon binding energies. Additionally, changes in the O 1s spectra could be explained in terms of bridging (BO)

Leon Black; Krassimir Garbev; Peter Stemmermann; Keith R. Hallam; Geoffrey C. Allen

2003-01-01

328

X-ray and. gamma. -ray spectroscopy of solids under pressure  

SciTech Connect

This report briefly describes our studies of various materials at high pressures by means of x-ray and {gamma}-ray absorption spectroscopy. High pressure provides a very effective means of studying materials. Virtually every property is altered from the color and crystal structure to the electrical and magnetic properties. The fundamental reason, of course, is that the quantum levels depend upon the atomic spacing so that both the electronic and vibrational structure is affected.

Ingalls, R.L.

1990-04-20

329

Fluorine-intercalated carbon fibers: II: An X-ray photoelectron spectroscopy study  

Microsoft Academic Search

The X-ray photoelectron spectroscopy study of fluorine-intercalated carbon fibers has shown the formation of semi-ionic bonding between carbon and intercalated fluorine species, leading to an increase in the positive charge on the involved carbon atoms and a subsequent increase in C 1s binding energy. Covalent C?F bonding is present at the external surface of the fibers. The relative amounts of

A. Tressaud; C. Guimon; V. Gupta; F. Moguet

1995-01-01

330

A von Hamos x-ray spectrometer based on a segmented-type diffraction crystal for single-shot x-ray emission spectroscopy and time-resolved resonant inelastic x-ray scattering studies  

SciTech Connect

We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV-9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

Szlachetko, J. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Institute of Physics, Jan Kochanowski University, 25-406 Kielce (Poland); Nachtegaal, M.; Boni, E. de; Willimann, M.; Safonova, O.; Sa, J.; Smolentsev, G.; Szlachetko, M.; Bergamaschi, A.; Schmitt, B.; David, C.; Luecke, A. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Bokhoven, J. A. van [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zuerich (Switzerland); Dousse, J.-Cl.; Hoszowska, J.; Kayser, Y. [Department of Physics, University of Fribourg, 1700 Fribourg (Switzerland); Jagodzinski, P. [University of Technology, Kielce (Poland)

2012-10-15

331

High-resolution X-ray spectroscopy of the planetary nebula BD+303639  

NASA Astrophysics Data System (ADS)

We present the results of the first X-ray gratings spectroscopy observations of a planetary nebula (PN) - the X-ray-bright, young BD +30 3639. We observed BD +30 3639 for a total of ~300 ks with the Chandra X- ray Observatory's Low Energy Transmission Gratings in combination with its Advanced CCD Imaging Spectrometer (LETG/ACIS-S). The LETG/ACIS results indicate that the X-ray source originates essentially from the present-day stellar wind (Ne/O and C/O are greatly enhanced over solar, while Fe/O is subsolar) and suggest the presence of a range of plasma temperatures from Tx ~ 1.7 MK to 2.9 MK and an intervening absorbing column NH ~ 2.4 x 10^21 cm^-2. The range of temperatures implied by the plasma model fitting offers the first direct indication of the presence of a temperature gradient within the wind-collision-generated 'hot bubble' of a planetary nebula, providing much-needed constraints on wind collision models; while the results for plasma abundances are important in the context of theories of nucleosynthesis during advanced evolutionary stages of intermediate-mass stars.

Yu, Y.

2009-09-01

332

Synchrotron X-ray Powder Diffraction and Absorption Spectroscopy in Pulsed Magnetic Fields with Milliseconds Duration  

SciTech Connect

X-ray Powder Diffraction and X-ray Absorption Spectroscopy experiments (WAS) and X-ray magnetic circular dichroism (XMCD) experiments were carried out at the ESRF DUBBLE beam line (BM26) and at the energy dispersive beam line (ID24), respectively. A mobile pulse generator, developed at the LNCMP, delivered 110kJ to the load coil, which was sufficient to generate peak fields of 30T with a rise time of about 5 ms. A liquid He flow cryostat allowed us to vary the sample temperature accurately between 4.2K and 300K.Powder diffraction patterns of TbVO4 were recorded in a broad temperature range using 21 keV monochromatic X-rays and using an on-line image plate detector. We observed the suppression of the Jahn-Teller structural distortion in TbVO4 due to the high magnetic pulsed field.XAS spectra could be measured and finite XMCD signals, directly proportional to the magnetic moment on the Gd absorber atom, were measured in thin Gd foils. Thanks to its element and orbital selectivity, XMCD proofs to be very useful in probing the magnetic properties and due to the strong brilliance of the synchrotron beam, the signals can be measured even in the ms range.

Vanacken, J. [LNCMP, 143, avenue de Rangueil BP 14245, F31432 Toulouse (France); Pulsveldengroep, INPAC, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Detlefs, C.; Mathon, O.; Dominguez, M.-C. [ESRF, BP 220, F-38043 Grenoble (France); Frings, P.; Duc, F.; Nardone, M.; Billette, J.; Zitouni, A.; Rikken, G. [LNCMP, 143, avenue de Rangueil BP 14245, F31432 Toulouse (France); Lorenzo, J. E. [Laboratoire de Cristallographie, CNRS, B.P.166X, F-38043 Grenoble (France); Herczeg, J.; Moshchalkov, V. V. [Pulsveldengroep, INPAC, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Bras, W. [DUBBLE CRG at ESRF, BP 220, F-38043 Grenoble (France)

2007-03-30

333

An X-ray spectroscopy system and its application to the laser-Compton scattering experiments  

NASA Astrophysics Data System (ADS)

One of the main challenges for the laser-Compton scattering (LCS) experiments with the oblique configuration at the Linac of SINAP is the low signal to noise (S/N) ratio due to the low intensity of LCS signals. X-ray spectroscopy system mainly consisting of an X-ray Si(Li) detector, electronics, and LabVIEW-based data acquisition has been developed for the low S/N ratio experiments. Spectral characteristics of such a system (i.e., energy and time resolutions, data acquisition efficiency, and system instability) have been determined by the 55Fe, 241Am, and 238Pu radioactive sources. In order to extract the LCS X-ray spectrum, several methods for the enhancement of the S/N ratio have been achieved and data have been taken alternatively with laser pulse on and off. Thanks to these methods the S/N ratios have been optimized. Finally, the generated LCS X-ray spectrum has been achieved through the subtraction of the on/off laser accumulated spectra.

Luo, W.; Xu, W.; Pan, Q. Y.; Fan, G. T.; Fan, G. W.; Li, Y. J.; Xu, B. J.; Xu, Y.; Yan, Z.; Yang, L. F.

2010-12-01

334

Synchrotron X-ray Powder Diffraction and Absorption Spectroscopy in Pulsed Magnetic Fields with Milliseconds Duration  

NASA Astrophysics Data System (ADS)

X-ray Powder Diffraction and X-ray Absorption Spectroscopy experiments (WAS) and X-ray magnetic circular dichroism (XMCD) experiments were carried out at the ESRF DUBBLE beam line (BM26) and at the energy dispersive beam line (ID24), respectively. A mobile pulse generator, developed at the LNCMP, delivered 110kJ to the load coil, which was sufficient to generate peak fields of 30T with a rise time of about 5 ms. A liquid He flow cryostat allowed us to vary the sample temperature accurately between 4.2K and 300K. Powder diffraction patterns of TbVO4 were recorded in a broad temperature range using 21 keV monochromatic X-rays and using an on-line image plate detector. We observed the suppression of the Jahn-Teller structural distortion in TbVO4 due to the high magnetic pulsed field. XAS spectra could be measured and finite XMCD signals, directly proportional to the magnetic moment on the Gd absorber atom, were measured in thin Gd foils. Thanks to its element and orbital selectivity, XMCD proofs to be very useful in probing the magnetic properties and due to the strong brilliance of the synchrotron beam, the signals can be measured even in the ms range.

Vanacken, J.; Detlefs, C.; Mathon, O.; Frings, P.; Duc, F.; Lorenzo, J. E.; Nardone, M.; Billette, J.; Zitouni, A.; Dominguez, M.-C.; Herczeg, J.; Bras, W.; Moshchalkov, V. V.; Rikken, G.

2007-03-01

335

X-ray and electron spectroscopy investigation of the core–shell nanowires of ZnO:Mn  

Microsoft Academic Search

ZnO\\/ZnO:Mn core–shell nanowires were studied by means of X-ray absorption spectroscopy of the Mn K- and L2,3-edges and electron energy loss spectroscopy of the O K-edge. The combination of conventional X-ray and nanofocused electron spectroscopies together with advanced theoretical analysis turned out to be fruitful for the clear identification of the Mn phase in the volume of the core–shell structures.

A. A. Guda; N. Smolentsev; J. Verbeeck; E. M. Kaidashev; Y. Zubavichus; A. N. Kravtsova; O. E. Polozhentsev; A. V. Soldatov

2011-01-01

336

Origin-independent calculation of quadrupole intensities in X-ray spectroscopy  

SciTech Connect

For electronic excitations in the ultraviolet and visible range of the electromagnetic spectrum, the intensities are usually calculated within the dipole approximation, which assumes that the oscillating electric field is constant over the length scale of the transition. For the short wavelengths used in hard X-ray spectroscopy, the dipole approximation may not be adequate. In particular, for metal K-edge X-ray absorption spectroscopy (XAS), it becomes necessary to include higher-order contributions. In quantum-chemical approaches to X-ray spectroscopy, these so-called quadrupole intensities have so far been calculated by including contributions depending on the square of the electric-quadrupole and magnetic-dipole transition moments. However, the resulting quadrupole intensities depend on the choice of the origin of the coordinate system. Here, we show that for obtaining an origin-independent theory, one has to include all contributions that are of the same order in the wave vector consistently. This leads to two additional contributions depending on products of the electric-dipole and electric-octupole and of the electric-dipole and magnetic-quadrupole transition moments, respectively. We have implemented such an origin-independent calculation of quadrupole intensities in XAS within time-dependent density-functional theory, and demonstrate its usefulness for the calculation of metal and ligand K-edge XAS spectra of transition metal complexes.

Bernadotte, Stephan; Atkins, Andrew J.; Jacob, Christoph R. [Karlsruhe Institute of Technology (KIT), Center for Functional Nanostructures and Institute of Physical Chemistry, Wolfgang-Gaede-Str. 1a, 76131 Karlsruhe (Germany)

2012-11-28

337

Origin-independent calculation of quadrupole intensities in X-ray spectroscopy.  

PubMed

For electronic excitations in the ultraviolet and visible range of the electromagnetic spectrum, the intensities are usually calculated within the dipole approximation, which assumes that the oscillating electric field is constant over the length scale of the transition. For the short wavelengths used in hard X-ray spectroscopy, the dipole approximation may not be adequate. In particular, for metal K-edge X-ray absorption spectroscopy (XAS), it becomes necessary to include higher-order contributions. In quantum-chemical approaches to X-ray spectroscopy, these so-called quadrupole intensities have so far been calculated by including contributions depending on the square of the electric-quadrupole and magnetic-dipole transition moments. However, the resulting quadrupole intensities depend on the choice of the origin of the coordinate system. Here, we show that for obtaining an origin-independent theory, one has to include all contributions that are of the same order in the wave vector consistently. This leads to two additional contributions depending on products of the electric-dipole and electric-octupole and of the electric-dipole and magnetic-quadrupole transition moments, respectively. We have implemented such an origin-independent calculation of quadrupole intensities in XAS within time-dependent density-functional theory, and demonstrate its usefulness for the calculation of metal and ligand K-edge XAS spectra of transition metal complexes. PMID:23205980

Bernadotte, Stephan; Atkins, Andrew J; Jacob, Christoph R

2012-11-28

338

Design of the Optical System for a New Time-Resolved X-ray Absorption Spectroscopy Apparatus.  

National Technical Information Service (NTIS)

Calculations of total reflection mirror optics and analyzing crystal polychromator optics are done to design a new time-resolved soft X-ray absorption spectroscopy apparatus. This apparatus utilizes pulsed soft X-rays of pseudo-continuum energy which are ...

A. Miyashita O. Yoda

1988-01-01

339

Microelemental and mineral compositions of pathogenic biomineral concrements: SRXFA, X-ray powder diffraction and vibrational spectroscopy data  

NASA Astrophysics Data System (ADS)

X-ray fluorescence analysis using synchrotron radiation (SRXRF), X-ray powder diffraction, infrared and Raman spectroscopy had been applied for determination of microelemental and mineral composition of the kidney stones, gallstones and salivalities from natives of Novosibirsk and Novosibirsk region, Russia. The relationship between mineral, organic and microelemental composition of pathogenic calcilus was shown.

Moroz, T. N.; Palchik, N. A.; Dar'in, A. V.

2009-05-01

340

Wavelength dispersive soft X-ray emission spectroscopy attached to TEM using multi-capirary X-ray lens  

Microsoft Academic Search

There is now growing interest in localized chemical bonding states in complex metals and insulators such as those containing\\u000a light elements, rare earths or transition metals because their key spectral features appear in the soft X-ray or vacuum UV\\u000a regions, which is not easily accessible to by SOR light sources and often includes crucial information to understand their\\u000a electronic, optical,

S. Muto; K. Tatsumi; H. Takahashi

341

Resonant Inelastic X-Ray Scattering in Hexagonal Boron Nitride Observed by Soft-X-Ray Fluorescence Spectroscopy  

Microsoft Academic Search

Photon-excited B K fluorescence spectra were measured for hexagonal boron nitride using tunable synchrotron radiation below and above the B K edge. We report Raman-like resonant inelastic scattering of soft x rays involving excitation of delocalized valence-band electrons. The inelastic scattering features track with the excitation energy below threshold, go through a resonance as the excitation is tuned to the

J. J. Jia; T. A. Callcott; Eric L. Shirley; J. A. Carlisle; L. J. Terminello; A. Asfaw; D. L. Ederer; F. J. Himpsel; R. C. C. Perera

1996-01-01

342

Resonant inelastic x-ray scattering in hexagonal boron nitride observed by soft-x-ray fluorescence spectroscopy  

Microsoft Academic Search

Photon-excited B {ital K} fluorescence spectra were measured for hexagonal boron nitride using tunable synchrotron radiation below and above the B {ital K} edge. We report Raman-like resonant inelastic scattering of soft x rays involving excitation of delocalized valence-band electrons. The inelastic scattering features track with the excitation energy below threshold, go through a resonance as the excitation is tuned

J. J. Jia; T. A. Callcott; Eric Shirley; J. A. Carlisle; L. J. Terminello; A. Asfaw; D. L. Ederer; F. J. Himpsel; R. C. Perera

1996-01-01

343

The experiment with the fast X-ray monitor (BRM) instrument onboard the CORONAS-PHOTON satellite  

Microsoft Academic Search

The “Fast X-ray Monitor” (BRM) instrument operated in the complex of the scientific instruments onboard the CORONAS-PHOTON\\u000a satellite from February 19, 2009, until December 1, 2009. The instrument is intended for the registration of the hard X-ray\\u000a radiation of solar flares in the 20–600 keV energy range in six differential energy channels (20–30, 30–40, 40–50, 50–70,\\u000a 70–130, and 130–600 keV)

Yu. A. Trofimov; V. N. Yurov; Yu. D. Kotov; E. A. Zhuchkova

2011-01-01

344

Infrared Hunting for New Hidden Hard X-ray Sources: Observations and Instrumentation  

NASA Astrophysics Data System (ADS)

Recently many new hard X-ray (e.g., 15-60 keV) sources have been discovered by X-ray satellites, especially by the INTEGRAL satellite equipped with a hard X-ray/soft gamma-ray observing capability. These new hard X-ray sources sometimes reveal enormous extinction of NH ? 1024 cm-2 which is why they have been hidden. They are usually highly-obscured X-ray binaries or active galactic nuclei of which soft X-ray emission (and also most of the ultra-violet and optical) is obscured by the surrounding medium. I introduce on-going observational efforts to study these new sources, especially the X-ray binaries, as well as a new near-infrared spectrograph for the Keck I telescope optimized for deciphering the nature of these new, heavily-obscured, hard X-ray sources.

Moon, D.-S.

2007-06-01

345

Development of a portable instrument for automated measurements of the detective quantum efficiency of x-ray detectors  

Microsoft Academic Search

The scientific community has generally adopted use of the modulation transfer function (MTF) and detective quantum efficiency (DQE) as primary measures of performance of radiographic detectors. However, measurement of these parameters is generally restricted to experts in laboratory environments due to the required x-ray physics knowledge, specialized instrumentation and computational analyses. We have developed a prototype instrument that automates both

I. A. Cunningham; S. Lazarev; M. Sattarivand; N. D. Jankovic

2007-01-01

346

First combined total reflection X-ray fluorescence and grazing incidence X-ray absorption spectroscopy characterization of aeolian dust archived in Antarctica and Alpine deep ice cores  

NASA Astrophysics Data System (ADS)

Aeolian mineral dust archived in polar and mid latitude ice cores represents a precious proxy for assessing environmental and climatic variations at different timescales. In this respect, the identification of dust mineralogy plays a key role. In this work we performed the first preliminary X-ray absorption spectroscopy (XAS) experiments on mineral dust particles extracted from Antarctic and from Alpine firn cores using grazing incidence geometry at the Fe K-edge. A dedicated high vacuum experimental chamber was set up for normal-incidence and total-reflection X-Ray Fluorescence and Absorption Spectroscopy analyses on minor amounts of mineral materials at the Stanford Synchrotron Radiation Laboratory. Results show that this experimental technique and protocol allows recognizing iron inclusion mineral fraction on insoluble dust in the 1-10 µg range.

Cibin, G.; Marcelli, A.; Maggi, V.; Sala, M.; Marino, F.; Delmonte, B.; Albani, S.; Pignotti, S.

2008-12-01

347

Disentangling atomic-layer-specific x-ray absorption spectra by Auger electron diffraction spectroscopy  

NASA Astrophysics Data System (ADS)

In order to investigate the electronic and magnetic structures of each atomic layer at subsurface, we have proposed a new method, Auger electron diffraction spectroscopy, which is the combination of x-ray absorption spectroscopy (XAS) and Auger electron diffraction (AED) techniques. We have measured a series of Ni LMM AED patterns of the Ni film grown on Cu(001) surface for various thicknesses. Then we deduced a set of atomic-layer-specific AED patterns in a numerical way. Furthermore, we developed an algorithm to disentangle XANES spectra from different atomic layers using these atomic-layer-specific AED patterns. Surface and subsurface core level shift were determined for each atomic layer.

Matsui, Fumihiko; Matsushita, Tomohiro; Kato, Yukako; Hashimoto, Mie; Daimon, Hiroshi

2009-11-01

348

X-ray photoelectron spectroscopy and auger electron spectroscopy studies of Al-doped ZnO films  

Microsoft Academic Search

The chemical state of oxygen, aluminum and zinc in Al-doped ZnO (ZAO) films was investigated by X-ray photoelectron spectroscopy (XPS), as well as the transition zone of the film-to-substrate, by auger electron spectroscopy (AES). The results show that zinc remains mostly in the formal valence states of Zn2+. A distinct asymmetry in Al 2p3\\/2 photoelectron peaks has been resolved into

M. Chen; X Wang; Y. H Yu; Z. L Pei; X. D Bai; C Sun; R. F Huang; L. S Wen

2000-01-01

349

Characterization of thin films on the nanometer scale by Auger electron spectroscopy and X-ray photoelectron spectroscopy  

Microsoft Academic Search

We describe two NIST databases that can be used to characterize thin films from Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) measurements. First, the NIST Electron Effective-Attenuation-Length Database provides values of effective attenuation lengths (EALs) for user-specified materials and measurement conditions. The EALs differ from the corresponding inelastic mean free paths on account of elastic-scattering of the signal

C. J. Powell; A. Jablonski; W. S. M. Werner; W. Smekal

2005-01-01

350

Characterization of Delhi iron pillar rust by X-ray diÄraction, Fourier transform infrared spectroscopy and Mossbauer spectroscopy  

Microsoft Academic Search

Rust samples obtained from the region just below the decorative bell capital of the Delhi iron pillar (DIP) have been analyzed by X-ray diÄraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mossbauer spectroscopy. The identification of iron hydrogen phosphate hydrate in the crystalline form by XRD was unambiguous. Very weak diÄraction from the oxyhydroxides\\/oxides of iron was observed indicating that

R. Balasubramaniam; A. V. Ramesh Kumar

351

X-ray absorption spectroscopy study of prototype chemical systems: Theory vs. experiment  

NASA Astrophysics Data System (ADS)

Understanding the details of the intensities and spectral shapes of x-ray absorption spectra is a long-standing problem in chemistry and physics. Here, I present detailed studies of x-ray absorption for prototypical liquids, solids and gases with the goal of enhancing our general understanding of core-level spectroscopy via comparisons of modern theory and experiment. In Chapter 2, I investigate the importance of quantum motions in the x-ray absorption spectra of simple gases. It is found that rare fluctuations in atomic positions can be a cause of features in the spectra of gaseous molecules. In Chapter 3, I explore a novel quantization scheme for the excited and ground state potential surfaces for an isolated nitrogen molecule. This allows for the explicit calculation of the "correct" transition energies and peak widths (i.e. without any adjustable parameters). In Chapter 4, the importance of nuclear motion in molecular solids is investigated for glycine. We find that the inclusion of these motions permits the spectrum to be accurately calculated without any additional adjustable parameters. In Chapter 5, I provide a detailed study of the hydroxide ion solvated in water. There has been recent controversy as to how hydroxide is solvated, with two principal models invoked. I show that some of the computational evidence favoring one model of solvation over the other has been either previously obtained with inadequate precision or via a method that is systematically biased. In Chapter 6, the measured and computed x-ray absorption spectra of pyrrole in both the gas phase and when solvated by water are compared. We are able to accurately predict the spectra in both cases. In Chapter 7, the measured x-ray absorption of a series of highly charged cationic salts (YBr3, CrCl3, SnCl4 , LaCl3 and InCl3) solvated in water are presented and explained. In Chapter 8, the measured x-ray absorption spectrum at the nitrogen K-edge of aqueous triglycine is presented, including effects of various salts which can alter its solubility. This is used to show that while x-ray absorption is sensitive to salt interactions with small peptides, it is unlikely to be a sensitive probe for overall protein structures, i.e. to distinguish beta sheet from an alpha helix at the nitrogen K-edge. Finally, in Chapter 9 future directions are discussed.

Schwartz, Craig Philip

352

Development of an x-ray beam line at the NSLS for studies in materials science using x-ray absorption spectroscopy: Annual progress report  

Microsoft Academic Search

Although only in operation since May, 1985, the X-11 participation research team (PRT) at the NSLS has already demonstrated that it is one of the leading centers of x-ray absorption spectroscopy (XAS). During this time, results have been obtained and programs initiated in a number of areas, for example: interfaces, including deposited metal-metal and metal-semiconductor systems, multilayers and ion implanted

1986-01-01

353

A unique 30 Tesla single-solenoid pulsed magnet instrument for x-ray studies  

NASA Astrophysics Data System (ADS)

We present a dual-cryostat pulsed-magnet instrument at the Advanced Photon Source (APS) with unique capabilities. The dual-cryostat independently cools the solenoid (Tohoku design) using liquid nitrogen and the sample using a closed-cycle refrigerator, respectively. Liquid nitrogen (LN) cooling allows a repetition rate of seven minutes for peak fields of 30 Tesla. The system is unique in that the LN cryostat incorporates a double-funnel vacuum tube passing through the solenoid's bore preserving the entire angular range allowed by the magnet. This scheme is advantageous in that it allows the applied magnetic field to be parallel to the scattering plane complementing typical split-pair magnets with fields normal to the scattering plane. Performance of the coils along with preliminary x-ray diffraction and spectroscopic studies will be presented.

Islam, Zahirul; Capatina, Dana; Ruff, Jacob; Das, Ritesh; Nojiri, Hiroyuki; Narumi, Yasuo

2011-03-01

354

Evolutionary developments in x-ray and electron energy loss microanalysis instrumentation for the analytical electron microscope  

SciTech Connect

Developments in instrumentation for both X-ray Dispersive and Electron Energy Loss Spectroscopy (XEDS/EELS) over the last ten years have given the experimentalist a greatly enhanced set of analytical tools for characterization. Microanalysts have waited for nearly two decades now in the hope of getting a true analytical microscope and the development of 300--400 kV instruments should have allowed us to attain this goal. Unfortunately, this has not generally been the case. While there have been some major improvements in the techniques, there has also been some devolution in the modern AEM (Analytical Electron Microscope) In XEDS, the majority of today's instruments are still plagued by the hole count effect, which was first described in detail over a fifteen years ago. The magnitude of this problem can still reach the 20% level for medium atomic number species in a conventional off-the-shelf intermediate voltage AEM. This is an absurd situation and the manufacturers should be severely criticized. Part of the blame, however, also rests on the AEM community for not having come up with a universally agreed upon standard test procedure. Fortunately, such a test procedure is in the early stages of refinement. The proposed test specimen consists of an evaporated Cr film {approximately}500--1000 {angstrom} thick supported upon a 3mm diameter Molybdenum 200{mu}m aperture.

Zaluzec, N.J.

1990-01-01

355

Galactic morphology and evolution through X-ray spectroscopy of the interstellar medium  

NASA Astrophysics Data System (ADS)

The interstellar medium (ISM) plays a key role in the evolution of the Galaxy: it is enriched by heavy elements produced in stars and acts as reservoir for new generations of stars. The circumgalactic medium (CGM), i.e. the interface between the galaxies and the intergalactic medium (IGM), is another important reservoir of gas for star formation in the Galactic disk and the depository of Galactic feedback. It is thought to be highly ionized and to contain the bulk of the missing baryons. It is possible to study spatial extent, thermal state and metal content of ISM, CGM and IGM, and their interaction with the nearby galaxies and the Milky Way, through combined UV / X-ray spectroscopy of background sources. In this talk, I will provide a brief introduction on the ISM and the dedicated high-resolution UV / X-ray spectroscopy of compact objects like X-ray binaries and AGN. The structure, dynamics and chemistry of the ISM will be discussed as well as its interaction with the Galactic evolution.

Pinto, Ciro

2012-07-01

356

X-ray absorption spectroscopy of cuprous-thiolate clusters in proteins and model systems  

SciTech Connect

Cuprous-thiolate multimetallic clusters exist in a range of different biological molecules for which no structural information exists from X-ray crystallography. Spectroscopic tools such as X-ray absorption spectroscopy have provided the major structural insights into this family of biological molecules. Recent nuclear magnetic resonance data on silver-substituted metallothionein, thought to be analogous with the copper proteins, have suggested the presence of digonal coordination. In order to test this in the copper case, we have examined a series of structurally characterized cuprous-thiolate model compounds, containing different proportions of digonal and trigonal copper sites, using copper K-edge X-ray absorption spectroscopy. The edge spectra, which have been previously used as a probe for the average copper coordination environment in proteins, show little variation between the models, indicating that these are not useful as a probe of coordination environment in the case of cuprous-thiolate clusters (as opposed to isolated metal sites). We show that systematic trends in the average Cu-S bond length from EXAFS curve-fitting analysis can be used to obtain an estimate of the fraction of digonal and trigonal copper sites. This correlation is applied to a series of different proteins containing cuprous-thiolate clusters which are found to contain significant fractions of digonal copper. 41 refs., 7 figs., 3 tabs.

Pickering, I.J.; George, G.N. (Stanford Univ., CA (United States)); Dameron, C.T.; Kurz, B.; Winge, D.R. (Univ. of Utah, Salt Lake City, UT (United States)); Dance, I.G. (Univ. of New South Wales, Kensington (Australia))

1993-10-20

357

Nitrogen bonding structure in carbon nitride thin films studied by soft x-ray spectroscopy  

NASA Astrophysics Data System (ADS)

Soft x-ray absorption (SXAS) and emission (SXES) spectroscopies were applied to study the nitrogen bonding structure in magnetron sputtered CNx thin films. By comparing with calculated spectra of N in different model systems, N in three main bonding environments can be identified: (i) CtrpbndN bonds, with a sharp SXAS peak at 399.5 eV, (ii) pyridine-like N (i.e., N bonded to two C atoms), with an x-ray absorption resonance at ~398.5 eV, and (iii) N substituted in graphite, possibly with one sp3 carbon as a neighbor (SXAS energy ~401 eV). These bondings are present in all CNx films analyzed; however, as shown earlier, the relative intensities between the peaks may vary with the growth conditions. Differences in the coordination of the nearest or second nearest C neighbors only cause slight changes in the peak positions and spectrum shape.

Hellgren, Niklas; Guo, Jinghua; Sa?The, Conny; Agui, Akane; Nordgren, Joseph; Luo, Yi; A?Gren, Hans; Sundgren, Jan-Eric

2001-12-01

358

X-ray absorption spectroscopy study on oxygen-deficient hafnium oxide film  

NASA Astrophysics Data System (ADS)

We investigated the influence of oxygen vacancy on the electronic and atomic distributions in hafnium oxide, using hard and soft x-ray absorption spectroscopies. Analyses on the Hf L3-edge extended x-ray absorption fine structures revealed that the average Hf-O bond length reduces more than -0.1 Å in the presence of oxygen vacancy, consequently on the lattice relaxation. Furthermore, the O K-edge absorption spectrum shows additional band tail state beneath the genuine Hf 5d conduction band, which manifests a small occupation in Hf d shell in the oxygen-deficient oxide. However, the nonzero d occupation is found not to involve a ferromagnetic spin correlation by the absence of features in the Hf N3-edge magnetic circular dichroism.

Cho, D.-Y.; Min, C.-H.; Kim, J.-Y.; Park, J.-H.; Oh, S.-J.; Hwang, C. S.

2008-03-01

359

Multiple core-hole coherence in x-ray four-wave-mixing spectroscopies  

SciTech Connect

Correlation-function expressions are derived for the coherent nonlinear response of molecules to three resonant ultrafast pulses in the x-ray regime. The ability to create two-core-hole states with controlled attosecond timing in four-wave-mixing and pump probe techniques should open up new windows into the response of valence electrons, which are not available from incoherent x-ray Raman and fluorescence spectroscopy. Closed expressions for the necessary four-point correlation functions are derived for the electron-boson model by using the second order cumulant expansion to describe the fluctuating potentials. The information obtained from multidimensional nonlinear techniques could be used to test and refine this model, and establish an anharmonic oscillator picture for electronic excitations.

Mukamel, Shaul [Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025 (United States)

2005-12-15

360

Determining the Grain Composition of the Interstellar Medium with High-Resolution X-Ray Spectroscopy  

NASA Astrophysics Data System (ADS)

We investigate the ability of high-resolution X-ray spectroscopy to directly probe the grain composition of the interstellar medium. Using iron K-edge experimental data of likely ISM dust candidates taken at the National Synchrotron Light Source at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory, we explore the prospects for determining the chemical composition of astrophysical dust and discuss a technique for doing so. Focusing on the capabilities of the Astro-E2 XRS microcalorimeters, we assess the limiting effects of spectral resolution and noise for detecting significant X-ray absorption fine structure signal in astrophysical environments containing dust. We find that given sufficient signal, the resolution of the XRS will allow us to definitively distinguish gas-phase from dust-phase absorption and certain chemical compositions.

Lee, Julia C.; Ravel, B.

2005-04-01

361

Electronic Structure of Warm Dense Copper Studied by Ultrafast X-Ray Absorption Spectroscopy  

SciTech Connect

We use time-resolved x-ray absorption spectroscopy to investigate the unoccupied electronic density of states of warm dense copper that is produced isochorically through the absorption of an ultrafast optical pulse. The temperature of the superheated electron-hole plasma, which ranges from 4000 to 10 000 K, was determined by comparing the measured x-ray absorption spectrum with a simulation. The electronic structure of warm dense copper is adequately described with the high temperature electronic density of state calculated by the density functional theory. The dynamics of the electron temperature is consistent with a two-temperature model, while a temperature-dependent electron-phonon coupling parameter is necessary.

Cho, B. I.; Engelhorn, K.; Feng, J.; Heimann, P. A. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Correa, A. A.; Ogitsu, T.; Ping, Y.; Nelson, A. J.; Lee, R. W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Weber, C. P. [Department of Physics, Santa Clara University, Santa Clara, California 95053 (United States); Lee, H. J. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Ni, P. A. [Accelerator and Fusion Research, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Prendergast, D. [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Falcone, R. W. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics, University of California, Berkeley, California 94720 (United States)

2011-04-22

362

X-ray laser-induced photoelectron spectroscopy for single-state measurements  

NASA Astrophysics Data System (ADS)

We demonstrate single-shot x-ray laser-induced time-of-flight photoelectron spectroscopy on metal and semiconductor surfaces with picosecond time resolution. Our compact multipulse terawatt tabletop x-ray laser source provides the necessary high photon flux (>1012/pulse), monochromaticity, picosecond pulse duration, and coherence for probing ultrafast changes in the chemical and electronic structure of these materials. Static valence band and shallow core-level photoemission spectra are presented for ambient temperature polycrystalline Cu foils and Ge(100). Surface contamination was removed by UV ozone cleaning prior to analysis. The ultrafast nature of this technique lends itself to true single-state measurements of shocked and heated materials.

Nelson, A. J.; Dunn, J.; van Buuren, T.; Hunter, J.

2004-12-01

363

Detection, identification and mapping of iron anomalies in brain tissue using X-ray absorption spectroscopy  

SciTech Connect

This work describes a novel method for the detection, identification and mapping of anomalous iron compounds in mammalian brain tissue using X-ray absorption spectroscopy. We have located and identified individual iron anomalies in an avian tissue model associated with ferritin, biogenic magnetite and haemoglobin with a pixel resolution of less than 5 {micro}m. This technique represents a breakthrough in the study of both intra- and extra-cellular iron compounds in brain tissue. The potential for high-resolution iron mapping using microfocused X-ray beams has direct application to investigations of the location and structural form of iron compounds associated with human neurodegenerative disorders - a problem which has vexed researchers for 50 years.

Mikhaylova, A.; Davidson, M.; Toastmann, H.; Channell, J.E.T.; Guyodo, Y.; Batich, C.; Dobson, J. (Keele); (Florida); (IRM)

2008-06-16

364

An 8x8 pixel IC for X-ray spectroscopy  

SciTech Connect

An integrated circuit providing 64 channels of low-noise signal processing electronics in an 8x8 pixel arrangement has been developed as part of an integrated silicon detector array for high count-rate x-ray spectroscopy applications. Each pixel features low-noise charge integration, programmable peaking time and gain, and an output driver. The 8x8 pixel IC builds upon our previous development of the XPS chip, a 1-dimensional preamplifier-shaper IC for linear silicon detector arrays. The new pixel design features significant improvements to the shaper and output driver stages, including digital peaking time and gain selection, and a low-power charge driver/receiver design. When operated with a cooled, low-capacitance silicon detector, an energy resolution of {approx} 210 eV FWHM was obtained for 5.89 keV x-rays.

Krieger, Bradley; Ewell, Kathryn; Ludewigt, Bernhard A.; Maier, Michael R.; Markovic, Dejan; Milgrome, Oren; Wang, Y. June

2000-11-03

365

An 8x8 pixel IC for X-ray spectroscopy  

SciTech Connect

An integrated circuit providing 64 channels of low-noise signal processing electronics in an 8x8 pixel arrangement has been developed as part of an integrated silicon detector array for high count-rate x-ray spectroscopy applications. Each pixel features low-noise charge integration, programmable peaking time and gain, and an output driver. The 8x8 pixel IC builds upon our previous development of the XPS chip, a 1-dimensional preamplifier-shaper IC for linear silicon detector arrays. The new pixel design features significant improvements to the shaper and output driver stages, including digital peaking time and gain selection, and a low-power charge driver/receiver design. When operated with a cooled, low-capacitance silicon detector, an energy resolution of {approx}210 eV FWHM was obtained for 5.89 keV x-rays.

Krieger, Bradley; Ewell, Kathryn; Ludewigt, Bernhard A.; Maier, Michael R.; Markovic, Dejan; Milgrome, Oren; Wang, Y. June

2000-11-03

366

[Measurement and analysis of lead in soil using X-ray fluorescence spectroscopy].  

PubMed

The present paper analyzed the characteristics of X-ray fluorescence spectroscopy (XRF) of metal element lead in soil using the NITON XLt793 portable X-ray fluorescence spectra of heavy metal analyzer under laboratory conditions. The characteristic spectral lines of L(alpha) (energy: 10. 55 keV) and L(beta) (energy: 12. 61 keV) with different matrix elements were selected respectively for lead in the experiment. By measuring the intensities of the characteristic spectral line with different Pb concentration, the results demonstrate that the relation between concentration [mass fraction 10 x 10(-6) - 1 800 x 10(-6)] of Pb element and the intensity of the characteristic spectrum is well linear. The calibration curve of Pb was plotted based on the different concentration measurement results, and the limit of detection of 7.89 x 10(-6) was obtained for Pb in soil. PMID:23697153

Zhang, Rong; Zhang, Yu-Jun; Zhang, Wei; Chen, Dong; Yu, Xiao-Ya; Gao, Yan-Wei

2013-02-01

367

Xe nanocrystals in Si studied by x-ray absorption fine structure spectroscopy  

SciTech Connect

The structural configuration of Xe clusters, obtained by ion implantation in a Si matrix, has been investigated as a function of the temperature by x-ray absorption fine structure spectroscopy. In contrast with previous results, we demonstrate that an accurate analysis of the data, using high order cumulants, gives evidence of Xe fcc nanocrystals at low temperature, even in the as-implanted Si; expansion of the Xe lattice is always found as a function of the temperature, with no appreciable overpressure. We point out that a dramatic modification of these conclusions can be induced by an incorrect analysis using standard symmetrical pair distribution function G(r); for this reason, all the results were checked by x-ray diffraction measurements.

Faraci, Giuseppe; Pennisi, Agata R.; Zontone, Federico [Dipartimento di Fisica e Astronomia, MATIS-Istituto Nazionale di Fisica della Materia, Universita di Catania, Via Santa Sofia 64, 95123 Catania (Italy); European Synchrotron Research Facility (ESRF), BP 220, F-38043 Grenoble Cedex (France)

2007-07-15

368

Cryogenic detector development at LLNL: ultraviolet x-ray, gamma-ray and biomolecule spectroscopy  

SciTech Connect

We are developing low-temperature detectors for optical, ultraviolet, X-ray, and gamma-ray spectroscopy, and for biomolecular mass spectrometry. We present development work on these detectors and materials analysis and biomolecular mass spectrometry. We have measured thin-film Nb/Al/Al2O3/AlNb superconducting tunnel junction (STJ) X-ray detectors in the 0.2 to 1 keV band with a range of different junction sizes and aluminum film thicknesses. In one case, we have achieved the statistical limit to the energy resolution of 13 eV FWHM at 227 eV with an output count rate of 20,600 cts/s.

Labov, S.E.; Frank, M.; le Grand, J.B. [and others

1997-08-12

369

In situ x-ray photoelectron spectroscopy for electrochemical reactions in ordinary solvents  

NASA Astrophysics Data System (ADS)

In situ electrochemical X-ray photoelectron spectroscopy (XPS) apparatus, which allows XPS at solid/liquid interfaces under potential control, was constructed utilizing a microcell with an ultra-thin Si membrane, which separates vacuum and a solution. Hard X-rays from a synchrotron source penetrate into the Si membrane surface exposed to the solution. Electrons emitted at the Si/solution interface can pass through the membrane and be analyzed by an analyzer placed in vacuum. Its operation was demonstrated for potential-induced Si oxide growth in water. Effect of potential and time on the thickness of Si and Si oxide layers was quantitatively determined at sub-nanometer resolution.

Masuda, Takuya; Yoshikawa, Hideki; Noguchi, Hidenori; Kawasaki, Tadahiro; Kobata, Masaaki; Kobayashi, Keisuke; Uosaki, Kohei

2013-09-01

370

X-ray fluorescence/Auger-electron coincidence spectroscopy of vacancy cascades in atomic argon  

SciTech Connect

Argon L{sub 2.3}-M{sub 2.3}M{sub 2.3} Auger-electron spectra were measured in coincidence with K{alpha} fluorescent x-rays in studies of Ar K-shell vacancy decays at several photon energies above the K-threshold and on the 1s-4p resonance in atomic argon. The complex spectra recorded by conventional electron spectroscopy are greatly simplified when recorded in coincidence with fluorescent x-rays, allowing a more detailed analysis of the vacancy cascade process. The resulting coincidence spectra are compared with Hartree-Fock calculations which include shake-up transitions in the resonant case. Small energy shifts of the coincidence electron spectra are attributed to post-collision interaction with 1s photoelectrons.

Arp, U. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Electron and Optical Physics Div.; LeBrun, T.; Southworth, S.H.; Jung, M. [Argonne National Lab., IL (United States). Physics Div.; MacDonald, M.A. [E.P.S.R.C. Daresbury Lab., Warrington (United Kingdom)

1996-12-01

371

Stability and transformation mechanism of weddellite nanocrystals studied by X-ray diffraction and infrared spectroscopy.  

PubMed

This study is focused on the stability of weddellite, the dihydrate phase of calcium oxalate [CaC(2)O(4)·(2 + x)H(2)O], mainly detected in kidney stones and in oxalate films found on the surfaces of several ancient monuments. Its occurrence is a critical issue since, at environmental conditions, weddellite is unstable and quickly changes into whewellite, the monohydrate phase of calcium oxalate (CaC(2)O(4)·H(2)O). New single crystal X-ray diffraction experiments have been carried out, which confirm the structural model of weddellite previously published. Synthesised nanocrystals of weddellite have been kept under different hygrometric conditions in order to study, by X-ray powder diffraction, the influence of humidity on their stability. Moreover, the mechanism of transformation of weddellite nanocrystals has been investigated by infrared spectroscopy using D(2)O as a structural probe. PMID:20931117

Conti, Claudia; Brambilla, Luigi; Colombo, Chiara; Dellasega, David; Gatta, G Diego; Realini, Marco; Zerbi, Giuseppe

2010-10-07

372

In situ system for X-ray absorption spectroscopy experiments to investigate nanoparticle crystallization.  

PubMed

A new furnace, based on a halogen lamp, and a sample cell have been designed and constructed for in situ X-ray absorption spectroscopy experiments in conventional and dispersive mode (transmission and fluorescence geometries). The main application of the apparatus is thermal treatment studies under controlled conditions for dynamical processes. The sol-gel (gelatin) method has been utilized to synthesize NiO nanoparticles. During this heating process, in situ Ni K-edge X-ray absorption near-edge structural measurements provided evidence of the evolution of a Ni environment until complete NiO nanoparticle crystallization. This case is reported in order to show the furnace performance in dispersive mode. PMID:17057324

Meneses, C T; Flores, W H; Sotero, A P; Tamura, E; Garcia, F; Sasaki, J M

2006-10-18

373

The nature of arsenic in uranium mill tailings by X-ray absorption spectroscopy  

NASA Astrophysics Data System (ADS)

In order to understand the evolving world of environmental issues, the ability to characterize and predict the stability and bioavailability of heavy métal contaminants in mine waste is becoming increasingly more important. X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopies were used to characterize a series of synthetic and natural samples associated with mine tailings processing. XANES was shown to be excellent as a tool to rapidly differentiate oxidation states of arsenic within the samples. The EXAFS spectra provided information on the mineralogy of the precipitated raffinate and tailings and showed that these samples are composed of a mixture of amorphous ferric arsenates, adsorbed arsenates and a mixture of other poorly ordered arsenates.

Cutler, J. N.; Chen, N.; Jiang, D. T.; Demopoulos, G. P.; Jia, Y.; Rowson, J. W.

2003-05-01

374

X-ray absorption spectroscopy of the dimeric iron site in azidomethemerythrin from Phascolopsis gouldii.  

PubMed Central

X-ray absorption spectroscopy has been used to study the dimeric iron center in azidomethemerythrin from Phascolopsis gouldii. Absorption edge data confirm that the two iron atoms are present as Fe(III) and suggest a hexa-coordination site for each of the iron atoms. The extended x-ray absorption fine structure (EXAFS) analysis provides direct structural evidence of a mu-oxo bridge between the two iron atoms at an average Fe-O distance of 1.71-1.76 A. Analysis using a multiple-scattering formalism calculates upper limits of 165 degrees for the Fe-O-Fe bridging angle and 3.38 A for the Fe-Fe distance. This result agrees with current crystallographic models being determined by refinement of structures of two azidomethemerythrins.

Hendrickson, W A; Co, M S; Smith, J L; Hodgson, K O; Klippenstein, G L

1982-01-01

375

X-ray absorption spectroscopy measurements of thin foil heating by Z-pinch radiation.  

PubMed

Absorption spectroscopy measurements of the time-dependent heating of thin foils exposed to intense z-pinch radiation sources are presented. These measurements and their analysis provide valuable benchmarks for, and insights into, the radiative heating of matter by x-ray sources. Z-pinch radiation sources with peak powers of up to 160 TW radiatively heated thin plastic-tamped aluminum foils to temperatures approximately 60 eV. The foils were located in open slots at the boundary of z-pinch hohlraums surrounding the pinch. Time-resolved Kalpha satellite absorption spectroscopy was used to measure the evolution of the Al ionization distribution, using a geometry in which the pinch served as the backlighter. The time-dependent pinch radius and x-ray power were monitored using framing camera, x-ray diode array, and bolometer measurements. A three-dimensional view factor code, within which one-dimensional (1D) radiation-hydrodynamics calculations were performed for each surface element in the view factor grid, was used to compute the incident and reemitted radiation flux distribution throughout the hohlraum and across the foil surface. Simulated absorption spectra were then generated by postprocessing radiation-hydrodynamics results for the foil heating using a 1D collisional-radiative code. Our simulated results were found to be in good general agreement with experimental x-ray spectra, indicating that the spectral measurements are consistent with independent measurements of the pinch power. We also discuss the sensitivity of our results to the spectrum of the radiation field incident on the foil, and the role of nonlocal thermodynamic equilibrium atomic kinetics in affecting the spectra. PMID:12443339

MacFarlane, J J; Bailey, J E; Chandler, G A; Deeney, C; Douglas, M R; Jobe, D; Lake, P; Nash, T J; Nielsen, D S; Spielman, R B; Wang, P; Woodruff, P

2002-10-28

376

Electronic Properties of Hydrogen Storage Materials with Photon-in/Photon-out Soft-X-Ray Spectroscopy  

SciTech Connect

The applications of resonant soft X-ray emission spectroscopy on a variety of carbon systems have yielded characteristic fingerprints. With high-resolution monochromatized synchrotron radiation excitation, resonant inelastic X-ray scattering has emerged as a new source of information about electronic structure and excitation dynamics. Photon-in/photon-out soft-X-ray spectroscopy is used to study the electronic properties of fundamental materials, nanostructure, and complex hydrides and will offer potential in-depth understanding of chemisorption and/or physisorption mechanisms of hydrogen adsorption/desorption capacity and kinetics.

Guo, Jinghua

2008-09-22

377

Inner-shell photoionization spectroscopy on deposited metal clusters using soft x-ray synchrotron radiation: An experimental setup  

SciTech Connect

Exploration of mass-selected clusters by soft x-ray synchrotron radiation is well suited to receive element specific information on clusters in contact with a support and to systematically follow the evolution of size-dependent electronic and geometrical properties from the smallest clusters toward the bulk. Here we describe an experimental setup, which combines cluster synthesis, mass selection, soft landing, ultrahigh vacuum transfer, and photoionization experiments such as x-ray photoelectron spectroscopy, x-ray absorption, and Auger electron spectroscopy. First spectroscopic results and experimental conditions are briefly discussed for Cu{sub 19} deposited onto the natural oxide layer of a Si-wafer surface.

Peters, S.; Peredkov, S.; Balkaya, B.; Ferretti, N.; Savci, A.; Vollmer, A.; Neeb, M.; Eberhardt, W. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Wilhelm-Conrad-Roentgen-Campus Adlershof, Elektronenspeicherring BESSY II, Albert-Einstein Strasse 15, D-12489 Berlin (Germany)

2009-12-15

378

The Suzaku High Resolution X-Ray Spectrometer  

Microsoft Academic Search

The X-Ray Spectrometer (XRS) has been designed to provide the Suzaku Observatory with non-dispersive, high-resolution X-ray spectroscopy. As designed, the instrument covers the energy range 0.3 to 12keV, which encompasses the most diagnostically rich part of the X-ray band. The sensor consists of a 32-channel array of X-ray microcalorimeters, each with an energy resolution of about 6eV. The very low

Richard L. Kelley; Kazuhisa Mitsuda; Christine A. Allen; Petar Arsenovic; Michael D. Audley; Thomas G. Bialas; Kevin R. Boyce; Robert F. Boyle; Susan R. Breon; Gregory V. Brown; Jean Cottam; Michael J. Dipirro; Ryuichi Fujimoto; Tae Furusho; Keith C. Gendreau; Gene G. Gochar; Oscar Gonzalez; Masayuki Hirabayashi; Stephen S. Holt; Hajime Inoue; Manabu Ishida; Yoshitaka Ishisaki; Carol S. Jones; Ritva Keski-Kuha; Caroline A. Kilbourne; Dan McCammon; Umeyo Morita; S. Harvey Moseley; Brent Mott; Katsuhiro Narasaki; Yoshiaki Ogawara; Takaya Ohashi; Naomi Ota; John S. Panek; F. Scott Porter; Aristides Serlemitsos; Peter J. Shirron; Gary A. Sneiderman; Andrew E. Szymkowiak; Yoh Takei; June L. Tveekrem; Stephen M. Volz; Mikio Yamamoto; Noriko Y. Yamasaki

2007-01-01

379

The focusing optics x-ray solar imager (FOXSI): instrument and first flight  

NASA Astrophysics Data System (ADS)

Solar flares accelerate particles up to high energies (MeV and GeV scales for electrons and ions, respectively) through efficient acceleration processes that are not currently understood. Hard X-rays (HXRs) are the most direct diagnostic of flare-accelerated electrons. However, past and current solar HXR observers lack the necessary sensitivity and imaging dynamic range to make detailed studies of faint HXR sources in the solar corona (where particle acceleration is thought to occur); these limitations are mainly due to the indirect Fourier imaging techniques used by these observers. With greater sensitivity and dynamic range, electron acceleration sites could be systematically studied in detail. Both these capabilities can be advanced by the use of direct focusing optics. The recently own Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload demonstrates the unique diagnostic power of focusing optics for observations of solar HXRs. FOXSI features grazing-incidence replicated nickel optics with 5 arcsecond resolution and fine-pitch silicon strip detectors with a 7.7 arcsecond strip pitch. FOXSI flew successfully on 2012 November 2, producing images and spectra of a microflare and performing a search for non-thermal emission (4{15 keV) from nanoflares occurring outside active regions in the quiet Sun. A future spacecraft version of FOXSI, featuring similar optics and detectors, could make detailed observations of HXRs from flare-accelerated electrons, identifying and characterizing particle acceleration sites and mapping out paths of energetic electrons as they leave these sites and propagate throughout the solar corona. This paper will describe the FOXSI instrument and present images from the first flight.

Krucker, Säm.; Christe, Steven; Glesener, Lindsay; Ishikawa, Shinnosuke; Ramsey, Brian; Gubarev, Mikhail; Saito, Shinya; Takahashi, Tadayuki; Watanabe, Shin; Tajima, Hiroyasu; Tanaka, Takaaki; Turin, Paul; Glaser, David; Fermin, Jose; Lin, Robert P.

2013-09-01

380

Ultrafast soft X-ray photoelectron spectroscopy at liquid water microjets.  

PubMed

Since the pioneering work of Kai Siegbahn, electron spectroscopy for chemical analysis (ESCA) has been developed into an indispensable analytical technique for surface science. The value of this powerful method of photoelectron spectroscopy (PES, also termed photoemission spectroscopy) and Siegbahn's contributions were recognized in the 1981 Nobel Prize in Physics. The need for high vacuum, however, originally prohibited PES of volatile liquids, and only allowed for investigation of low-vapor-pressure molecules attached to a surface (or close to a surface) or liquid films of low volatility. Only with the invention of liquid beams of volatile liquids compatible with high-vacuum conditions was PES from liquid surfaces under vacuum made feasible. Because of the ubiquity of water interfaces in nature, the liquid water-vacuum interface became a most attractive research topic, particularly over the past 10 years. PES studies of these important aqueous interfaces remained significantly challenging because of the need to develop high-pressure PES methods. For decades, ESCA or PES (termed XPS, for X-ray photoelectron spectroscopy, in the case of soft X-ray photons) was restricted to conventional laboratory X-ray sources or beamlines in synchrotron facilities. This approach enabled frequency domain measurements, but with poor time resolution. Indirect access to time-resolved processes in the condensed phase was only achieved if line-widths could be analyzed or if processes could be related to a fast clock, that is, reference processes that are fast enough and are also well understood in the condensed phase. Just recently, the emergence of high harmonic light sources, providing short-wavelength radiation in ultrashort light pulses, added the dimension of time to the classical ESCA or XPS technique and opened the door to (soft) X-ray photoelectron spectroscopy with ultrahigh time resolution. The combination of high harmonic light sources (providing radiation with laserlike beam qualities) and liquid microjet technology recently enabled the first liquid interface PES experiments in the IR/UV-pump and extreme ultraviolet-probe (EUV-probe) configuration. In this Account, we highlight features of the technology and a number of recent applications, including extreme states of matter and the discovery and detection of short-lived transients of the solvated electron in water. Properties of the EUV radiation, such as its controllable polarization and features of the liquid microjet, will enable unique experiments in the near future. PES measures electron binding energies and angular distributions of photoelectrons, which comprise unique information about electron orbitals and their involvement in chemical bonding. One of the future goals is to use this information to trace molecular orbitals, over time, in chemical reactions or biological transformations. PMID:22075058

Faubel, M; Siefermann, K R; Liu, Y; Abel, B

2011-11-10

381

Characterization of the Carancas-Puno meteorite by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy  

NASA Astrophysics Data System (ADS)

We report the results of the study of a meteorite that impacted an inhabited zone on 15 September 2007 in the neighborhood of the town of Carancas, Puno Region, about 1,300 km south of Lima. The analysis carried out by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy (at room temperature and at 4.2 K), reveal the presence in the meteorite sample of magnetic sites assigned to taenite (Fe,Ni) and troilite (Fe,S) phases, and of two paramagnetic doublets assigned to Fe2 + , one associated with olivine and the other to pyroxene. In accord with these results, this meteorite is classified as a type IV chondrite meteorite.

Cerón Loayza, María L.; Bravo Cabrejos, Jorge A.

2011-08-01

382

Study of hard disk and slider surfaces using X-ray photoemission electron microscopy and near-edge X-ray absorption fine structure spectroscopy  

SciTech Connect

X-ray Photo Emission Electron Microscopy (X-PEEM) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy were applied to study the properties of amorphous hard carbon overcoats on disks and sliders, and the properties of the lubricant. The modification of lubricants after performing thermal desorption studies was measured by NEXAFS, and the results are compared to the thermal desorption data. The study of lubricant degradation in wear tracks is described. Sliders were investigated before and after wear test, and the modification of the slider coating as well as the transfer of lubricant to the slider was studied. The studies show that the lubricant is altered chemically during the wear. Fluorine is removed and carboxyl groups are formed.

Anders, S.; Stammler, T. [Lawrence Berkeley National lab., CA (United States). Advanced Light Source Div.; Bhatia, C.S. [SSD/IBM, San Jose, CA (United States); Stoehr, J. [IBM Research Div., San Jose, CA (United States). Almaden Research Center; Fong, W.; Chen, C.Y.; Bogy, D.B. [Univ. of California, Berkeley, CA (United States)

1998-04-01

383

Ultra-small-angle X-ray scattering-X-ray photon correlation spectroscopy studies of incipient structural changes in amorphous calcium phosphate-based dental composites.  

PubMed

The local structural changes in amorphous calcium phosphate (ACP)-based dental composites were studied under isothermal conditions using both static, bulk measurement techniques and a recently developed methodology based on combined ultra-small angle X-ray scattering-X-ray photon correlation spectroscopy (USAXS-XPCS), which permits a dynamic approach. While results from conventional bulk measurements do not show clear signs of structural change, USAXS-XPCS results reveal unambiguous evidence for local structural variations on a similar time scale to that of water loss in the ACP fillers. A thermal-expansion-based simulation indicates that thermal behavior alone does not account for the observed dynamics. Together, these results suggest that changes in the water content of ACP affect the composite morphology due to changes in ACP structure that occur without an amorphous-to-crystalline conversion. It is also noted that biomedical materials research could benefit greatly from USAXS-XPCS, a dynamic approach. PMID:22374649

Zhang, Fan; Allen, Andrew J; Levine, Lyle E; Espinal, Laura; Antonucci, Joseph M; Skrtic, Drago; O'Donnell, Justin N R; Ilavsky, Jan

2012-02-28

384

ATOMIC AND MOLECULAR PHYSICS: X-ray absorption near the edge structure and X-ray photoelectron spectroscopy studies on pyrite prepared by thermally sulfurizing iron films  

NASA Astrophysics Data System (ADS)

This paper reports how pyrite films were prepared by thermal sulfurization of magnetron sputtered iron films and characterized by x-ray absorption near edge structure spectra and x-ray photoelectron spectroscopy on a 4B9B beam line at the Beijing Synchrotron Radiation Facility. The band gap of the pyrite agrees well with the optical band gap obtained by a spectrophotometer. The octahedral symmetry of pyrite leads to the splitting of the d orbit into t2g and eg levels. The high spin and low spin states were analysed through the difference of electron exchange interaction and the orbital crystal field. Only when the crystal field splitting is higher than 1.5 eV, the two weak peaks above the white lines can appear, and this was approved by experiments in the present work.

Zhang, Hui; Liu, Ying-Shu; Wang, Bao-Yi; Wei, Long; Kui, Re-Xi; Qian, Hai-Jie

2009-07-01

385

Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav  

NASA Astrophysics Data System (ADS)

The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893-972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts.

Blagoev, K.; Grozeva, M.; Malcheva, G.; Neykova, S.

2013-01-01

386

Characterization of the Carancas-Puno meteorite by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy  

NASA Astrophysics Data System (ADS)

We report the results of the study of a meteorite that impacted an inhabited zone on 15 September 2007 in the neighborhood of the town of Carancas, Puno Region, about 1,300 km south of Lima. The analysis carried out by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy (at room temperature and at 4.2 K), reveal the presence in the meteorite sample of magnetic sites assigned to taenite (Fe,Ni) and troilite (Fe,S) phases, and of two paramagnetic doublets assigned to Fe2 + , one associated with olivine and the other to pyroxene. In accord with these results, this meteorite is classified as a type IV chondrite meteorite.

Cerón Loayza, María L.; Bravo Cabrejos, Jorge A.

2011-11-01

387

X-ray spectroscopy of MXB 1728-34 with XMM-Newton  

NASA Astrophysics Data System (ADS)

We analyzed an XMM-Newton observation of the low-mass X-ray binary and atoll source MXB 1728-34. The source was in a low-luminosity state during the XMM-Newton observation, corresponding to a bolometric X-ray luminosity of 5 × 1036 d5.1 kpc2 erg s-1. The 1-11 keV X-ray spectrum of the source, obtained combining data from all the five instruments on-board XMM-Newton, is well fitted by a Comptonized continuum. Evident residuals are present at 6-7 keV, which are ascribed to the presence of a broad iron emission line. This feature can be equally well fitted by a relativistically smeared line or by a self-consistent, relativistically smeared reflection model. Under the hypothesis that the iron line is produced by reflection from the inner accretion disk, we can infer important information on the physical parameters of the system, such as the inner disk radius, Rin = 25-100 km, and the inclination of the system, 44° < i < 60°.

Egron, E.; di Salvo, T.; Burderi, L.; Papitto, A.; Barragán, L.; Dauser, T.; Wilms, J.; D'Aì, A.; Riggio, A.; Iaria, R.; Robba, N. R.

2011-06-01

388

CHANDRA GRATING SPECTROSCOPY OF THE Be/X-RAY BINARY 1A 0535+262  

SciTech Connect

We present Chandra HETGS spectroscopy of the Be/X-ray binary 1A 0535+262 obtained during the 2009/2010 giant outburst. These are the first CCD grating spectra of this type of system during a giant outburst. Our spectra reveal a number of lines including a narrow Fe K{alpha} emission line with an FWHM of {approx}5000 km s{sup -1}. For the first time, we detect the presence of a highly ionized outflow in a Be/X-ray binary. Assuming that the line is He-like Fe XXV, fits with a simple Gaussian imply an outflow velocity of {approx}1500 km s{sup -1}. However, self-consistent photoionization modeling with XSTAR suggests that Fe XXIII-XXIV must also contribute. In this case, an outflow velocity of {approx}3000 km s{sup -1} is implied. These results are discussed in the context of accretion flow in Be-star, neutron star, and black hole X-ray binaries.

Reynolds, Mark T.; Miller, Jon M., E-mail: markrey@umich.ed [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)

2010-11-10

389

X-ray absorption spectroscopy study of Gd3+-loaded ultra-short carbon nanotubes  

NASA Astrophysics Data System (ADS)

We present an x-ray absorption spectroscopy study of the local structure around the Gd3+ion loaded in ultra short (20-100 nm) carbon nanotubes (GNTs). X-ray Gd L3 absorption near edge structure data shows that the 31.2-?M GNT suspension exhibits a clear characteristic of hydration at the [GdOn] cluster. Extended x-ray absorption fine structure data show that the Gd3+ ion is coordinated by about 9 oxygen ions and that this first coordination shell exhibits an asymmetry similar to that found in triclinic Gd-acetate or Gd[C2H3O2]3·4H2O or GdAc. After correction for the asymmetry using the cumulant of the third order, the Gd-O bond distance is found to be 2.345 Å, instead of 2.406 Å for a symmetrical (or Gaussian) distribution. It is shorter than that in the Gd-containing MRI contrast agents currently in clinical uses. This may account in part for high proton relaxivity observed for the GNT suspension.

Ma, Q.; Jebb, M.; Tweedle, M. F.; Wilson, L. J.

2013-04-01

390

Infrared and X-ray simultaneous spectroscopy: a novel conceptual beamline design for time resolved experiments.  

PubMed

Many physical/chemical processes such as metal-insulator transitions or self-assembly phenomena involve correlated changes of electronic and atomic structure in a wide time range from microseconds to minutes. To investigate these dynamic processes we not only need a highly brilliant photon source in order to achieve high spatial and time resolution but new experimental methods have to be implemented. Here we present a new optical layout for performing simultaneous or concurrent infrared and X-ray measurements. This approach may indeed return unique information for example the interplay between structural changes and chemical processes occurring in the investigated sample. A beamline combining two X-ray and IR beams may really take advantage of the unique synchrotron radiation properties: the high brilliance and the broad spectrum. In this contribution we will describe the conceptual layout and the expected performance of a complex system designed to collect IR and X-ray radiation from the same bending magnet on a third-generation synchrotron radiation ring. If realized, this beamline will enable time-resolved spectroscopy experiments offering new scientific opportunities at the frontiers of science. PMID:20461504

Marcelli, Augusto; Xu, Wei; Hampai, Dariush; Malfatti, Luca; Innocenzi, Plinio; Schade, Ulrich; Wu, Ziyu

2010-05-12

391

Electron-ion interaction cross sections determined by x-ray spectroscopy on EBIT  

SciTech Connect

The Livermore electron beam ion trap (EBIT) is used to measure electron-ion interactions with high-resolution x-ray spectroscopy. Measurements are presented of the K{alpha} x-ray emission of heliumlike Fe{sup 24+} that demonstrate the effect of various processes on the spectrum of highly charged heliumlike ions. In particular, we have studied how dielectronic recombination into high-n Rydberg levels and resonance excitation processes contribute to the x-ray emission near threshold for direct electron-impact excitation. From these and other measurements we infer the cross sections for impact excitation of heliumlike titanium, chromium, manganese, and iron. Comparing the results with theoretical cross sections from distorted-wave calculations we find excellent agreement for all transitions but the heliumlike resonance transition from 1s2p {sup 1}P{sub 1} to ground, whose excitation cross section is measured to be 10%--20% smaller than calculated. 36 refs., 6 figs., 1 tab.

Beiersdorfer, P.; Cauble, R.; Chantrenne, S.; Chen, M.; Knapp, D.; Marrs, R.; Phillips, T.; Reed, K.; Schneider, M.; Scofield, J.; Wong, K.; Vogel, D.; Zasadzinski, R. (Lawrence Livermore National Lab., CA (USA)); Wargelin, B. (California Univ., Berkeley, CA (USA). Space Sciences Lab.); Bitter, M.; von Goeler, S. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

1991-06-26

392

Dynamics and rheology under continuous shear flow studied by x-ray photon correlation spectroscopy  

NASA Astrophysics Data System (ADS)

X-ray photon correlation spectroscopy (XPCS) has emerged as a unique technique allowing the measurement of dynamics of materials on mesoscopic lengthscales. One of the most common problems associated with the use of bright x-ray beams is beam-induced radiation damage, and this is likely to become an even more limiting factor at future synchrotron and free-electron laser sources. Flowing the sample during data acquisition is one of the simplest methods allowing the radiation damage to be limited. In addition to distributing the dose over many different scatterers, the method also enables new functionalities such as time-resolved studies. Here, we further develop a recently proposed experimental technique that combines XPCS and continuously flowing samples. More specifically, we use a model colloidal suspension to show how the macroscopic advective response to flow and the microscopic dissipative dynamics (diffusion) can be quantified from the x-ray data. Our results show very good quantitative agreement with a Poisseuille-flow hydrodynamical model combined with Brownian mechanics. The method has many potential applications, e.g. in the study of dynamics of glasses and gels under continuous shear/flow, protein aggregation processes and the interplay between dynamics and rheology in complex fluids.

Fluerasu, Andrei; Kwasniewski, Pawel; Caronna, Chiara; Destremaut, Fanny; Salmon, Jean-Baptiste; Madsen, Anders

2010-03-01

393

Surface Change in Titanium Subhydride Between 25 and 700 exp 0 C Studied by Auger Electron Spectroscopy and X-Ray Photoelectron Spectroscopy.  

National Technical Information Service (NTIS)

The surface sensitive spectroscopic techniques of Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) have been applied to the study of the oxide dissolution of titanium and titanium subhydride. In an earlier study using AES, it w...

P. S. Wang R. S. Carlson T. N. Wittberg

1982-01-01

394

Soft-test\\/repair of ccd-based digital x-ray instrumentation  

Microsoft Academic Search

Absfrncl - Modern x-ray imaging systems evolve toward digifindim for re- duced eost, foster time-todiagnosis ondimproved diagnostic eonfurmer. For the digitalx-ray systems, CCD (Charge Coupled Device) technology is eom- manly used lo ddect and digitize optical x-ray imgr This pper presents n novel sofr-lesUrepoir approach to overcome the defective pirelproblem in CCD (Charge Coupled Device)-based digital x-ray system through theoret-

B. Jin; K. M. George; M. Choi; M. Yeary; Y. B. Kim

2003-01-01

395

X-ray Spectroscopy of K- and L-shell Z-pinch and Astrophysical Plasmas  

SciTech Connect

In recent years, there have been significant advances in instrumental capabilities for making X-ray spectroscopic measurements of astrophysical plasmas. There have been corresponding improvements in X-ray diagnostics for advanced multi-mega-ampere pulse power machines that produce increasingly large radiative yields from gas-puff and wire array Z pinch plasmas. Analysis used for Z pinches can be used to study ICF and also astrophysical plasmas where laboratory measurements and simulations are the only means to interpret observed data. The astrophysical data for Fe, the most cosmically abundant high Z element, can provide a wealth of information about cosmic plasmas. Fe is also the key element in stainless steel (SS) wire arrays that are investigated as an intense X-ray radiation source at the Z machine at Sandia National Laboratories. The implosion dynamics of an array of wires on the Z and/or refurbished Z accelerator produces an abundance of radiation from the K- and L-shell ionization stages. These dynamic plasmas are inherently non-LTE, with opacity and other factors influencing the X-ray output. As the plasma assembles on axis, a number of time resolved snapshots provide temperature and density profiles and map the emitting region. We will analyze the ionization dynamics and generate K- and L-shell spectra using the conditions generated in the Z and/or refurbished Z accelerator, described by a 1-D non-LTE radiation-hydrodynamics model. Diagnostics based on spectral shape of L-shell emissions are inherently more difficult than those based on K-shell emissions because of more complex multiplet structures and line overlaps. The non-LTE populations are obtained by using detailed atomic models that include all important excitation, ionization, and recombination processes. We will highlight the connection between laboratory Z-pinch plasma simulations and astrophysical plasmas.

Dasgupta, A.; Davis, J.; Giuliani, J. G. [Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States); Clark, R. W. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States)

2009-09-10

396

Study of a chemically amplified resist for X-ray lithography by Fourier transform infrared spectroscopy.  

PubMed

Future applications of microelectromechanical systems (MEMS) require lithographic performance of very high aspect ratio. Chemically amplified resists (CARs) such as the negative tone commercial SU-8 provide critical advantages in sensitivity, resolution, and process efficiency in deep ultraviolet, electron-beam, and X-ray lithographies (XRLs), which result in a very high aspect ratio. In this investigation, an SU-8 resist was characterized and optimized for X-ray lithographic applications by studying the cross-linking process of the resist under different conditions of resist thickness and X-ray exposure dose. The exposure dose of soft X-ray (SXR) irradiation at the average weighted wavelength of 1.20 nm from a plasma focus device ranges from 100 to 1600 mJ/cm(2) on the resist surface. Resist thickness varies from 3.5 to 15 mum. The cross-linking process of the resist during post-exposure bake (PEB) was accurately monitored using Fourier transform infrared (FT-IR) spectroscopy. The infrared absorption peaks at 862, 914, 972, and 1128 cm(-1) in the spectrum of the SU-8 resist were found to be useful indicators for the completion of cross-linking in the resist. Results of the experiments showed that the cross-linking of SU-8 was optimized at the exposure dose of 800 mJ/cm(2) for resist thicknesses of 3.5, 9.5, and 15 microm. PEB temperature was set at 95 degrees C and time at 3 min. The resist thickness was measured using interference patterns in the FT-IR spectra of the resist. Test structures with an aspect ratio 3:1 on 10 microm thick SU-8 resist film were obtained using scanning electron microscopy (SEM). PMID:18070406

Tan, T L; Wong, D; Lee, P; Rawat, R S; Patran, A

2004-11-01

397

Ultraprecision motion control technique for high-resolution x-ray instrumentation  

SciTech Connect

With the availability of third-generation hard x-ray synchrotron radiation sources, such as the Advanced Photon Source (APS) at Argonne National Laboratory, x-ray inelastic scattering and x-ray nuclear resonant scattering provide powerful means for investigating the vibrational dynamics of a variety of materials and condensed matter systems. Novel high-resolution hard x-ray optics with meV energy resolution requires a compact positioning mechanism with 20--50-nrad angular resolution and stability. In this paper, the authors technical approach to this design challenge is presented. Sensitivity and stability test results are also discussed.

Shu, D.; Toellner, T. S.; Alp, E. E.

2000-07-17

398

X-ray photoelectron spectroscopy study of polyimide thin films with Ar cluster ion depth profiling  

SciTech Connect

X-ray photoelectron spectroscopy depth profiling of polyimide thin films on silicon substrates using an Ar cluster ion beam results in an extremely low degradation of the polyimide chemistry. In the range from 2.5 to 20 kV, a lower cluster ion energy produces a lower sputter induced damage to the polymer and results in an improved polyimide to silicon interface width. The sputtering rates of the polyimide are found to increase exponentially with an increase in the Ar cluster ion energy.

Miyayama, T.; Sanada, N.; Suzuki, M.; Hammond, J. S.; Si, S.-Q. D.; Takahara, A. [ULVAC-PHI, Inc., 370 Enzo, Chigasaki, Kanagawa 253-8522 (Japan); Physical Electronics, Inc., 18725 Lake Drive East, Chanhassen, Minnesota 55317 (United States); Institute for Materials Chemistry and Engineering, Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

2010-03-15

399

X-ray photoelectron spectroscopy studies of alkoxide-derived lithium niobate  

SciTech Connect

X-ray photoelectron spectroscopy was used to study the thermal conversion of Li, Nb alkoxide derived thin layers on Si(100). Changes in the surface composition with temperature indicated a decomposition process involving lithium transport to the surface, lithium carbonate or oxycarbonate formation, and subsequent reaction to form lithium niobate. For comparison purposes, spectra were also obtained for a single crystal of lithium niobate and layers prepared from sol-gel derived lithium ethoxide and niobium ethoxide. Heat treatment of the individual precursors gave lithium carbonate (or oxycarbonate) and niobium oxide, respectively. {copyright} {ital 1996 American Vacuum Society}

Kaufherr, N.; Eichorst, D.J.; Payne, D.A. [Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory]|[Beckman Institute, University of Illinois at Urbana--Champaign, Urbana, Illinois 61801 (United States)

1996-03-01

400

X-Ray Absorption Spectroscopy as a Probe of Elemental Speciation  

SciTech Connect

An effective bioremediation strategy for metals and metalloids must take the chemical state of the contaminants into account. The oxidation state and local atomic environment of contaminants critically affect such factors as their mobility, reactivity and toxicity, and hence the remediation strategy which might be applied. Since contamination exists in diverse environments, it is very likely that the chemical state of the contaminant will be site specific. X-ray absorption spectroscopy provides a unique tool for determining the chemical form of contaminants in most matrices with minimal pretreatment of the sample.

Pickering, Ingrid

2003-09-25

401

Quantitative x-ray photoelectron spectroscopy study of Al/AlOx bilayers  

NASA Astrophysics Data System (ADS)

An x-ray photoelectron spectroscopy (XPS) analysis of Nb/Al wedge bilayers, oxidized by both plasma and natural oxidation, is reported. The main goal is to show that the oxidation state--i.e., O:(oxidize)Al ratio--, structure and thickness of the surface oxide layer, as well as the thickness of the metallic Al leftover, as functions of the oxidation procedure, can be quantitatively evaluated from the XPS spectra. This is relevant to the detailed characterization of the insulating barriers in (magnetic) tunnel junctions.

Batlle, Xavier; Hattink, Bart Jan; Labarta, Amilcar; Akerman, Johan J.; Escudero, Roberto; Schuller, Ivan K.

2002-06-01

402

Magnetism in FeO at Megabar Pressures from X-Ray Emission Spectroscopy  

SciTech Connect

We report evidence for a preserved magnetic state in FeO up to 143 GPa at room temperature using high-resolution x-ray emission spectroscopy. This observation is based on the spectral line shape of the Fe K{beta} emission line. Up to the highest pressure, FeO remains a magnetic insulator. Combining our results with previous Moessbauer data, we present a new magnetic phase diagram of FeO. Features like a closed-loop P-T antiferromagnetic domain confirm that high-pressure investigations can reveal new physical properties and unexpected phenomena. (c) 1999 The American Physical Society.

Badro, James; Struzhkin, Viktor V.; Shu, Jinfu; Hemley, Russell J.; Mao, Ho-kwang; Kao, Chi-chang; Rueff, Jean-Pascal; Shen, Guoyin

1999-11-15

403

X-Ray Absorption Spectroscopy of Cuprous-Thiolate Clusters in Saccharomyces Cerevisiae Metallothionein  

SciTech Connect

Copper (Cu) metallothioneins are cuprous-thiolate proteins that contain multimetallic clusters, and are thought to have dual functions of Cu storage and Cu detoxification. We have used a combination of X-ray absorption spectroscopy (XAS) and density-functional theory (DFT) to investigate the nature of Cu binding to Saccharomyces cerevisiae metallothionein. We found that the XAS of metallothionein prepared, containing a full complement of Cu, was quantitatively consistent with the crystal structure, and that reconstitution of the apo-metallothionein with stoichiometric Cu results in the formation of a tetracopper cluster, indicating cooperative binding of the Cu ions by the metallothionein.

Zhang, L.; Pickering, I.J.; Winge, D.R.; George, G.N.

2009-05-28

404

X-ray Spectroscopy of E2 and M3 Transitions in Ni-like W  

SciTech Connect

The electric quadrupole (E2) and magnetic octupole (M3) ground state transitions in Ni-like W{sup 46+} have been measured using high-resolution crystal spectroscopy at the Livermore electron beam ion trap facility. The lines fall in the soft x-ray region near 7.93 {angstrom} and were originally observed as an unresolved feature in tokamak plasmas. Using flat ADP and quartz crystals the wavelengths, intensities, and polarizations of the two lines have been measured for various electron beam energies and compared to intensity and polarization calculations performed using the Flexible Atomic Code (FAC).

Clementson, J; Beiersdorfer, P; Gu, M F

2009-11-09

405

Oxidation of stepped Pt(111) studied by x-ray photoelectron spectroscopy and density functional theory  

SciTech Connect

In this comparative density functional theory and x-ray photoelectron spectroscopy study on the interaction of oxygen with stepped Pt(111) surfaces, we show that both the initial adsorption and oxidation occur at the steps rather than terraces. An equivalent behavior was observed for the oxide formation at higher chemical potentials, where, after the formation of a one-dimensional PtO{sub 2}-type oxide at the steps, similar oxide chains form on the (111) terraces, indicating the initial stages of bulk oxide formation.

Bandlow, Jochen; Kaghazchi, Payam; Jacob, Timo [Institut fuer Elektrochemie, Universitaet Ulm, Albert-Einstein-Allee 47, D-89069 Ulm (Germany); Papp, C.; Traenkenschuh, B.; Streber, R.; Lorenz, M. P. A.; Fuhrmann, T.; Steinrueck, H.-P. [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, D-91058 Erlangen (Germany); Denecke, R. [Wilhelm-Ostwald-Institut fuer Physikalische und Theoretische Chemie, Universitaet Leipzig, Linnestr. 2, D-04103 Leipzig (Germany)

2011-05-01

406

X-ray spectroscopy of E2 and M3 transitions in Ni-like W  

SciTech Connect

The electric quadrupole (E2) and magnetic octupole (M3) ground-state transitions in Ni-like W{sup 46+} have been measured using high-resolution crystal spectroscopy at the LLNL electron-beam ion trap facility. The lines fall in the soft x-ray region near 7.93 A and were originally observed as an unresolved feature in tokamak plasmas. Using flat ammonium dihydrogen phosphate and quartz crystals, the wavelengths, intensities, and polarizations of the two lines have been measured for various electron-beam energies and compared to intensity and polarization calculations performed using the Flexible Atomic Code (FAC).

Clementson, J.; Beiersdorfer, P.; Gu, M. F. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2010-01-15

407

Contact-free pyroelectric measurements using x-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

Non-contact pyroelectricity measurements based on x-ray photoelectron spectroscopy (XPS) are presented. Applied to Lithium Tantalate crystals, we demonstrate how the XPS-derived surface potential provides a simple probe of the desired property, free of all top-contact related difficulties. In particular, the increase in Lithium Tantalate spontaneous polarization under cooling, an experimentally challenging feature, is evaluated. We further inspect the roll of surface contaminants and the control over trapped surface charge in the XPS vacuum environment. Our approach can be extended to other non-contact probes, as well as to measuring additional electrical properties, such as piezoelectricity and ferroelectricity.

Ehre, D.; Cohen, H.

2013-07-01

408

Meeting Report: International Workshop for New Opportunities in Hard X-ray Photoelectron Spectroscopy: HAXPES 2009  

SciTech Connect

The third international workshop on hard X-ray photoelectron spectroscopy (HAXPES 2009) was held at Brookhaven National Laboratory, Upton, New York, from May 20-22, 2009. This three-day workshop brought together approximately 100 scientists from 14 countries to discuss progress and future prospects for this rapidly developing field of research. The conference was sponsored by the National Synchrotron Light Source, the National Synchrotron Light Source-II Project, Brookhaven National Laboratory Condensed Matter Physics and Materials Science Department, and the National Institute of Standards and Technology.

Woicik, J.; Fischer, D; Vescovo, E; Arena, D; Starr, D; Wells, B; Fadley, C

2010-01-01

409

X-ray absorption spectroscopy studies of electrochemically deposited thin oxide films.  

SciTech Connect

We have utilized ''in situ'' X-ray Absorption Fine Structure Spectroscopy to investigate the structure and composition of thin oxide films of nickel and iron that have been prepared by electrodeposition on a graphite substrate from aqueous solutions. The films are generally disordered. Structural information has been obtained from the analysis of the data. We also present initial findings on the local structure of heavy metal ions, e.g. Sr and Ce, incorporated into the electrodeposited nickel oxide films. Our results are of importance in a number of technological applications, among them, batteries, fuel cells, electrochromic and ferroelectric materials, corrosion protection, as well as environmental speciation and remediation.

Balasubramanian, M.

1998-06-02

410

Analysis by X-ray photoelectron spectroscopy of ruthenium stabilised polynuclear hexacyanometallate film electrodes  

Microsoft Academic Search

The role and effects of ruthenium on the electrochemical stabilisation of some metal-hexacyanometallate film electrodes was investigated by X-ray photoelectron spectroscopy (XPS). The following inorganic films were studied, cobalt(II)-hexacyanoferrate(II\\/III) (CoHCFe), nickel(II)-hexacyanoferrate(II\\/III) (NiHCFe), and iron(II\\/III)-hexacyanorutenate(II\\/III) (FeHCRu), and their corresponding ruthenium stabilised ones, Ru-CoHCFe, Ru-NiHCFe and Ru-FeHCRu. A mass increase of CoHCFe, NiHCFe, and FeHCRu, during continuous redox cycles (75–90 times) in

Giuseppe E. De Benedetto; Maria R. Guascito; Rosanna Ciriello; Tommaso R. I. Cataldi

2000-01-01

411

Characterization of Colloidal Quantum Dot Ligand Exchange by X-ray Photoelectron Spectroscopy  

NASA Astrophysics Data System (ADS)

Colloidal quantum dots (CQDs) are chemically synthesized semiconductor nanoparticles with size-dependent wavelength tunability. Chemical synthesis of CQDs involves the attachment of long organic surface ligands to prevent aggregation; however, these ligands also impede charge transport. Therefore, it is beneficial to exchange longer surface ligands for shorter ones for optoelectronic devices. Typical characterization techniques used to analyze surface ligand exchange include Fourier-transform infrared spectroscopy, x-ray diffraction, transmission electron microscopy, and nuclear magnetic resonance spectroscopy, yet these techniques do not provide a simultaneously direct, quantitative, and sensitive method for evaluating surface ligands on CQDs. In contrast, x-ray photoelectron spectroscopy (XPS) can provide nanoscale sensitivity for quantitative analysis of CQD surface ligand exchange. A unique aspect of this work is that a fingerprint is identified for shorter surface ligands by resolving the regional XPS spectrum corresponding to different types of carbon bonds. In addition, a deposition technique known as resonant infrared matrix-assisted pulsed laser evaporation is used to improve the CQD film uniformity such that stronger XPS signals are obtained, enabling more accurate analysis of the ligand exchange process.

Atewologun, Ayomide; Ge, Wangyao; Stiff-Roberts, Adrienne D.

2013-05-01

412

Three-Dimensional Electron Realm in VSe2 by Soft-X-Ray Photoelectron Spectroscopy: Origin of Charge-Density Waves  

NASA Astrophysics Data System (ADS)

The resolution of angle-resolved photoelectron spectroscopy (ARPES) in three-dimensional (3D) momentum k is fundamentally limited by ill defined surface-perpendicular wave vector k? associated with the finite photoelectron mean free path. Pushing ARPES into the soft-x-ray energy region sharpens the k? definition, allowing accurate electronic structure investigations in 3D materials. We apply soft-x-ray ARPES to explore the 3D electron realm in a paradigm transition metal dichalcogenide VSe2. Essential to break through the dramatic loss of the valence band photoexcitation cross section at soft-x-ray energies is the advanced photon flux performance of our synchrotron instrumentation. By virtue of the sharp 3D momentum definition, the soft-x-ray ARPES experimental band structure and Fermi surface of VSe2 show a textbook clarity. We identify pronounced 3D warping of the Fermi surface and show that its concomitant nesting acts as the precursor for the exotic 3D charge-density waves in VSe2. Our results demonstrate the immense potential of soft-x-ray ARPES to explore details of 3D electronic structure.

Strocov, Vladimir N.; Shi, Ming; Kobayashi, Masaki; Monney, Claude; Wang, Xiaoqiang; Krempasky, Juraj; Schmitt, Thorsten; Patthey, Luc; Berger, Helmuth; Blaha, Peter

2012-08-01

413

Three-dimensional electron realm in VSe2 by soft-x-ray photoelectron spectroscopy: origin of charge-density waves.  

PubMed

The resolution of angle-resolved photoelectron spectroscopy (ARPES) in three-dimensional (3D) momentum k is fundamentally limited by ill defined surface-perpendicular wave vector k(perpendicular) associated with the finite photoelectron mean free path. Pushing ARPES into the soft-x-ray energy region sharpens the k(perpendicular) definition, allowing accurate electronic structure investigations in 3D materials. We apply soft-x-ray ARPES to explore the 3D electron realm in a paradigm transition metal dichalcogenide VSe2. Essential to break through the dramatic loss of the valence band photoexcitation cross section at soft-x-ray energies is the advanced photon flux performance of our synchrotron instrumentation. By virtue of the sharp 3D momentum definition, the soft-x-ray ARPES experimental band structure and Fermi surface of VSe2 show a textbook clarity. We identify pronounced 3D warping of the Fermi surface and show that its concomitant nesting acts as the precursor for the exotic 3D charge-density waves in VSe2. Our results demonstrate the immense potential of soft-x-ray ARPES to explore details of 3D electronic structure. PMID:23002761

Strocov, Vladimir N; Shi, Ming; Kobayashi, Masaki; Monney, Claude; Wang, Xiaoqiang; Krempasky, Juraj; Schmitt, Thorsten; Patthey, Luc; Berger, Helmuth; Blaha, Peter

2012-08-20

414

Optomechanical Design of a Hard X-ray Nanoprobe Instrument with Nanometer-Scale Active Vibration Control  

SciTech Connect

We are developing a new hard x-ray nanoprobe instrument that is one of the centerpieces of the characterization facilities of the Center for Nanoscale Materials being constructed at Argonne National Laboratory. This new probe will cover an energy range of 3-30 keV with 30-nm spacial resolution. The system is designed to accommodate x-ray optics with a resolution limit of 10 nm, therefore, it requires staging of x-ray optics and specimens with a mechanical repeatability of better than 5 nm. Fast feedback for differential vibration control between the zone-plate x-ray optics and the sample holder has been implemented in the design using a digital-signal-processor-based real-time closed-loop feedback technique. A specially designed, custom-built laser Doppler displacement meter system provides two-dimensional differential displacement measurements with subnanometer resolution between the zone-plate x-ray optics and the sample holder. The optomechanical design of the instrument positioning stage system with nanometer-scale active vibration control is presented in this paper.

Shu, D.; Preissner, C.; Smolyanitskiy, A. [APS Engineering Support Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Maser, J.; Winarski, R. [Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439 (United States); X-ray Sciences Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Holt, M.; Lai, B.; Vogt, S. [X-ray Sciences Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Stephenson, G. B. [Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439 (United States); Materials Sciences Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

2007-01-19

415

Optomechanical design of a hard x-ray nanoprobe instrument with active vibration control in nanometer scale.  

SciTech Connect

We are developing a new hard x-ray nanoprobe instrument that is one of the centerpieces of the characterization facilities of the Center for Nanoscale Materials being constructed at Argonne National Laboratory. This new probe will cover an energy range of 3-30 keV with 30-nm spatial resolution. The system is designed to accommodate x-ray optics with a resolution limit of 10 nm, therefore, it requires staging of x-ray optics and specimens with a mechanical repeatability of better than 5 nm. Fast feedback for differential vibration control between the zone-plate x-ray optics and the sample holder has been implemented in the design using a digital-signal-processor-based real-time closed-loop feedback technique. A specially designed, custom-built laser Doppler displacement meter system provides two-dimensional differential displacement measurements with subnanometer resolution between the zone-plate x-ray optics and the sample holder. The optomechanical design of the instrument positioning stage system with nanometer-scale active vibration control is presented in this paper.

Shu, D.; Maser, J.; Holt, M.; Winarski, R.; Preissner, C.; Smolyanitskiy, A.; Lai, B.; Vogt, S.; Stephenson, G.

2007-01-01

416

Measurement of c-axis angular orientation in calcite (CaCO3) nanocrystals using X-ray absorption spectroscopy  

PubMed Central

We demonstrate that the ability to manipulate the polarization of synchrotron radiation can be exploited to enhance the capabilities of X-ray absorption near-edge structure (XANES) spectroscopy, to include linear dichroism effects. By acquiring spectra at the same photon energies but different polarizations, and using a photoelectron emission spectromicroscope (PEEM), one can quantitatively determine the angular orientation of micro- and nanocrystals with a spatial resolution down to 10 nm. XANES-PEEM instruments are already present at most synchrotrons, hence these methods are readily available. The methods are demonstrated here on geologic calcite (CaCO3) and used to investigate the prismatic layer of a mollusk shell, Pinctada fucata. These XANES-PEEM data reveal multiply oriented nanocrystals within calcite prisms, previously thought to be monocrystalline. The subdivision into multiply oriented nanocrystals, spread by more than 50°, may explain the excellent mechanical properties of the prismatic layer, known for decades but never explained.

Gilbert, P. U. P. A.; Young, Anthony; Coppersmith, Susan N.

2011-01-01

417

The design and application of an in-laboratory diffraction-enhanced x-ray imaging instrument  

SciTech Connect

We describe the design and application of a new in-laboratory diffraction-enhanced x-ray imaging (DEXI) instrument that uses a nonsynchrotron, conventional x-ray source to image the internal structure of an object. In the work presented here, a human cadaveric thumb is used as a test-sample to demonstrate the imaging capability of our instrument. A 22 keV monochromatic x-ray beam is prepared using a mismatched, two-crystal monochromator; a silicon analyzer crystal is placed in a parallel crystal geometry with the monochromator allowing both diffraction-enhanced imaging and multiple-imaging radiography to be performed. The DEXI instrument was found to have an experimentally determined spatial resolution of 160{+-}7 {mu}m in the horizontal direction and 153{+-}7 {mu}m in the vertical direction. As applied to biomedical imaging, the DEXI instrument can detect soft tissues, such as tendons and other connective tissues, that are normally difficult or impossible to image via conventional x-ray techniques.

Nesch, Ivan; Fogarty, Daniel P.; Tzvetkov, Tochko; Reinhart, Benjamin; Walus, A. Charles [Nesch, LLC 9800 Connecticut Drive, Crown Point, Indiana 46307 (United States); Khelashvili, Gocha [Nesch, LLC 9800 Connecticut Drive, Crown Point, Indiana 46307 (United States); Department of Radiation Oncology, Rush University Medical Center, 500 S. Paulina St., Chicago, Illinois 60612 (United States); Muehleman, Carol [Department of Biochemistry, Rush Medical College, 1735 W. Harrison St., Chicago, Illinois 60612 (United States); Chapman, Dean [Department of Anatomy and Cell Biology, College of Medicine, B331 Life Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N5E5 (Canada)

2009-09-15

418

Phase-resolved optical and X-ray spectroscopy of low-mass X-ray binary X1822-371  

NASA Astrophysics Data System (ADS)

Context. X1822-371 is the prototypical accretion disc corona X-ray source, a low-mass X-ray binary viewed at very high inclination, thereby allowing the disc structure and extended disc coronal regions to be visible. As the brightest (closest) such source, X1822-371 is ideal for studying the shape and edge structure of an accretion disc, and comparing with detailed models. Aims: We study the structure of the accretion disc in X1822-371 by modelling the phase-resolved spectra both in optical and X-ray regime. Methods: We analyse high time resolution optical ESO/VLT spectra of X1822-371 to study the variability in the emission line profiles. In addition, we use data from XMM-Newton space observatory to study phase-resolved as well as high resolution X-ray spectra. We apply the Doppler tomography technique to reconstruct a map of the optical emission distribution in the system. We fit multi-component models to the X-ray spectra. Results: We find that our results from both the optical and X-ray analysis can be explained with a model where the accretion disc has a thick rim in the region where the accretion stream impacts the disc. The behaviour of the H? line complex implies that some of the accreting matter creates an outburst around the accretion stream impact location and that the resulting outflow of matter moves both away from the accretion disc and towards the centre of the disc. Such behaviour can be explained by an almost isotropic outflow of matter from the accretion stream impact region. The optical emission lines of He ii ?4686 and 5411 show double peaked profiles, typical for an accretion disc at high inclination. However, their velocities are slower than expected for an accretion disc in a system like X1822-371. This, combined with the fact that the He ii emission lines do not get eclipsed during the partial eclipse in the continuum, suggests that the line emission does not originate in the orbital plane and is more likely to come from above the accretion disc, for example the accretion disc wind. Based on observations obtained at the European Southern Observatory, Chile (Program-ID: 077.D-0603(A)) and with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

Somero, A.; Hakala, P.; Muhli, P.; Charles, P.; Vilhu, O.

2012-03-01

419

DNA-modified silicon nanocrystals studied by X-ray luminescence and X-ray absorption spectroscopies: Observation of a strong infra-red luminescence band  

NASA Astrophysics Data System (ADS)

Silicon nanocrystals (SiNCs) modified with 18-mer DNA oligonucleotides have been studied by X-ray excited optical luminescence (XEOL) and X-ray absorption spectroscopy (XAS) in photoluminescence yield (PLY) and total electron yield (TEY) modes. Luminescence spectra from the DNA-modified SiNCs under X-ray excitation display distinct differences from simple alkyl terminated SiNCs. The DNA-modified SiNCs show strong luminescence at 540 +/- 10 nm under vacuum ultraviolet excitation which is assigned to nitrogen 1s - ?* transitions within the DNA bases. Under excitation at 130 eV the PLY spectra from the same samples show the native nanocrystal ultraviolet emission band is suppressed, and the strongest emission peak is red shifted from 430 +/- 10 nm to 489 +/- 10 nm which we attribute to base nitrogen 1s transitions. In addition, a strong emission band in the infrared region at 815 +/- 10 nm is observed. This clearly resolved strong IR band from the DNA-modified SiNCs may provide a useful luminescence signature in cell-labeling techniques and open up a range of applications for invivo assays.

Coxon, P. R.; Newman, M.; Hunt, M. R. C.; O'Farrell, N.; Horrocks, B. R.; Poolton, N. R. J.; Šiller, L.

2012-03-01

420

A new flexible monochromator setup for quick scanning x-ray absorption spectroscopy  

SciTech Connect

A new monochromator setup for quick scanning x-ray absorption spectroscopy in the subsecond time regime is presented. Novel driving mechanics allow changing the energy range of the acquired spectra by remote control during data acquisition for the first time, thus dramatically increasing the flexibility and convenience of this method. Completely new experiments are feasible due to the fact that time resolution, edge energy, and energy range of the acquired spectra can be changed continuously within seconds without breaking the vacuum of the monochromator vessel and even without interrupting the measurements. The advanced mechanics are explained in detail and the performance is characterized with x-ray absorption spectra of pure metal foils. The energy scale was determined by a fast and accurate angular encoder system measuring the Bragg angle of the monochromator crystal with subarcsecond resolution. The Bragg angle range covered by the oscillating crystal can currently be changed from 0 deg. to 3.0 deg. within 20 s, while the mechanics are capable to move with frequencies of up to ca. 35 Hz, leading to ca. 14 ms/spectrum time resolution. A new software package allows performing programmed scan sequences, which enable the user to measure stepwise with alternating parameters in predefined time segments. Thus, e.g., switching between edges scanned with the same energy range is possible within one in situ experiment, while also the time resolution can be varied simultaneously. This progress makes the new system extremely user friendly and efficient to use for time resolved x-ray absorption spectroscopy at synchrotron radiation beamlines.

Stoetzel, J.; Luetzenkirchen-Hecht, D.; Frahm, R. [Fachbereich C, Physik, Bergische Universitaet Wuppertal, Gaussstr. 20, 42097 Wuppertal (Germany)

2010-07-15

421

A New Flexible Monochromator Setup for Quick Scanning X-ray Absorption Spectroscopy  

SciTech Connect

A new monochromator setup for quick scanning x-ray absorption spectroscopy in the subsecond time regime is presented. Novel driving mechanics allow changing the energy range of the acquired spectra by remote control during data acquisition for the first time, thus dramatically increasing the flexibility and convenience of this method. Completely new experiments are feasible due to the fact that time resolution, edge energy, and energy range of the acquired spectra can be changed continuously within seconds without breaking the vacuum of the monochromator vessel and even without interrupting the measurements. The advanced mechanics are explained in detail and the performance is characterized with x-ray absorption spectra of pure metal foils. The energy scale was determined by a fast and accurate angular encoder system measuring the Bragg angle of the monochromator crystal with subarcsecond resolution. The Bragg angle range covered by the oscillating crystal can currently be changed from 0{sup o} to 3.0{sup o} within 20 s, while the mechanics are capable to move with frequencies of up to ca. 35 Hz, leading to ca. 14 ms/spectrum time resolution. A new software package allows performing programmed scan sequences, which enable the user to measure stepwise with alternating parameters in predefined time segments. Thus, e.g., switching between edges scanned with the same energy range is possible within one in situ experiment, while also the time resolution can be varied simultaneously. This progress makes the new system extremely user friendly and efficient to use for time resolved x-ray absorption spectroscopy at synchrotron radiation beamlines.

Stotzel, J.; Lutzenkirchen-Hecht, D; Frahm, R

2010-01-01

422

First results from the high-brightness x-ray spectroscopy beamline 9. 3.1 at ALS  

SciTech Connect

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range. This beamline is designed to achieve the goal of high brightness at the sample for use in the X-ray Atomic and Molecular Spectroscopy (XAMS) science, surface and interface science, biology, and x-ray optical development programs at ALS. X-ray absorption and time of flight photoemission measurements in 2 - 5 keV photon energy along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented.

Ng, W.; Jones, G.; Perera, R.C.C.

1995-10-01

423

Very high resolution UV and x-ray spectroscopy and imagery of solar active regions. Final report  

SciTech Connect

A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft x-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the x-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical x-ray observations using this new technique.

Bruner, M.; Brown, W.A.; Haisch, B.M.

1987-01-01

424

Quantitative spectroscopy of x-ray lines and continua in Tokamaks  

SciTech Connect

Crystal and synthetic multilayer diffractors, deployed either as flat Bragg reflectors, or curved, as in the Johann configuration, are used to study the spectrum of COMPASS-D and other tokamaks in the wavelength region of 1{endash}100 {Angstrom}. In this article, we concentrate on the measurement of absolute photon fluxes and the derivation of volume emissivities of the lines and continua in the x-ray region. The sensitivities of these instruments to absolute photon flux have been constructed {ital ab initio} from the individual component efficiencies, including published values of the diffractor reflectivities, which have been checked or supplemented by measurements using a double-axis goniometer or from line branching ratios. For those tokamak plasmas, where the elemental abundances and effective ion charge are documented, the x-ray continuum intensity itself has been used as a calibration source to derive absolute instrument sensitivity, in reasonable agreement with the {ital ab initio} method. In the COMPASS-D Tokamak, changes in the effective ion charge state, {ital Z}{sub eff}, have been derived for different operating conditions, from the absolute intensity of the continuum at {approximately}4 {Angstrom}. From the radiances of the line emission, changes in the absolute level of impurities following {open_quotes}boronization{close_quotes} of the vacuum vessel have also been documented. {copyright} {ital 1997 American Institute of Physics.}

Peacock, N.J.; Barnsley, R.; Lawson, K.D.; Melnick, I.M.; OMullane, M.G.; Singleton, M.A.; Patel, A. [UKAEA-Fusion (Euratom/UKAEA Fusion Association), Culham Laboratory, Abingdon, Oxfordshire OX14 3DB (United Kingdom)

1997-04-01

425

Near-Edge X-Ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold  

SciTech Connect

Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 and 0.16 {+-} 0.04 eV, respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different degrees of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond nanoparticles.

Willey, T.M.; Fabbri, J.D.; Lee, J.R.I.; Schreiner, P.R.; Fokin, A.A.; Tkachenko, B.A.; Fokina, N.A.; Dahl, J.E.P.; Carlson, R.M.K.; Vance, A.L.; Yang, W.; Terminello, L.J.; Buuren, T.van; Melosh, N.A.

2009-05-26

426

Structural characterization of Ni-Al (111) interface by surface x-ray absorption spectroscopy  

NASA Astrophysics Data System (ADS)

The evolution of the Ni/Al(111) interface has been studied in situ by x-ray absorption spectroscopy at the Ni-K edge. Ni films were deposited on bulk Al(111) with thickness ranging from 2 monolayers (ML) up to 30 ML. The aim was to determine the diffusion length of Ni and the phases that have formed. Ni diffused spontaneously at room temperature to a depth that we estimated to be of the order of 11 ML. The structure of Ni/Al(111) mixed interface has been characterized by x-ray absorption spectroscopy. With respect to previous studies on Al(110) the first phase formed on Al(111) is Al3Ni2-like instead of AlNi-like. Accordingly to previous observations, an AlNi3 phase forms on top of Al3Ni2 after the deposition of the first few monolayers. We propose that the pure Ni growth observed after deposition of 11 ML is due to the presence of the AlNi3 aluminide that acts as a diffusion barrier preventing deeper Ni penetration into Al at room temperature.

Damoc, L.; Fonda, E.; Le Fevre, P.; Traverse, A.

2002-08-01

427

XPS: A multi-channel preamplifier shaper IC for X-ray spectroscopy  

SciTech Connect

An integrated circuit featuring 48 channels of charge-sensitive preamplifiers followed by variable-gain pulse shaping amplifiers is being developed as part of an x-ray spectrometer with a highly segmented detector to handle high fluxes in synchrotron experiments. Such detector systems can provide excellent energy resolution combined with one-dimensional spatial information. The IC combines many basic spectroscopy amplifier functions with a low-noise preamplifier section to produce a unique circuit capable of driving conventional ADC modules directly. An important feature of the design is the novel CR-RC{sup 2} pulse shaper. In this section, high-linearity transconductor circuits are required in order to provide a broad range of continuously variable peaking times while still maintaining the linearity and noise performance necessary for x-ray spectroscopy. Reported here are first measurements made on the performance of a 16-channel prototype integrated circuit. At present, the preamplifier-shaper circuit achieves an equivalent input noise of 26 electrons rms at 2 {micro}s peaking time with a 0.2 pF external capacitor, which is similar to the capacitance of a single detector element. The design was fabricated in standard 1.2 {micro}m CMOS technology.

Krieger, B.; Kipnis, I.; Ludewigt, B.A.

1997-11-01

428

XPS: A multi-channel preamplifier-shaper IC for X-ray spectroscopy  

SciTech Connect

An integrated circuit featuring 48 channels of charge-sensitive preamplifiers followed by variable-gain pulse shaping amplifiers is being developed as part of an x-ray spectrometer with a highly segmented detector to handle high fluxes in synchrotron experiments. Such detector systems can provide excellent energy resolution combined with one-dimensional spatial information. The IC combines many basic spectroscopy amplifier functions with a low-noise preamplifier section to produce a unique circuit capable of driving conventional ADC modules directly. An important feature of the design is the novel CR-RC{sup 2} pulse shaper. In this section, high-linearity transconductor circuits are required in order to provide a broad range of continuously variable peaking times while still maintaining the linearity and noise performance necessary for x-ray spectroscopy. Reported here are first measurements made on the performance of a 16-channel prototype integrated circuit. At present, the preamplifier-shaper circuit achieves an equivalent input noise of 26 electrons rms at 2 {micro}s peaking time with a 0.2 pF external capacitor, which is similar to the capacitance of a single detector element. The design was fabricated in standard 1.2 {micro}m CMOS technology.

Krieger, B.; Ludewigt, B.A. [Lawrence Berkeley National Lab., CA (United States); Kipnis, I. [Hewlett-Packard Co., Newark, CA (United States)

1998-06-01

429

Near-Edge X-ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold  

SciTech Connect

Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface-modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 eV and 0.16 {+-} 0.04 eV respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different amounts of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond clusters.

Willey, T M; Fabbri, J; Lee, J I; Schreiner, P; Fokin, A A; Tkachenko, B A; Fokina, N A; Dahl, J; Carlson, B; Vance, A L; Yang, W; Terminello, L J; van Buuren, T; Melosh, N

2007-11-27

430

Soft X-ray spectroscopy and quantum chemistry characterization of defects in onion-like carbon produced by nanodiamond annealing  

Microsoft Academic Search

The electronic structure of onion-like carbon (OLC) consisted of quasi-spherical and polyhedral nanoparticles and produced as a result of nanodiamond annealing at 1800 K and 2140 K has been probed by soft X-ray emission and X-ray absorption spectroscopy. The enhanced density of states in the vicinity of the Fermi level was revealed for OLC prepared at moderate temperature. Ab initio calculation on

L. G. Bulusheva; A. V. Okotrub; V. L. Kuznetsov; D. V. Vyalikh

2007-01-01

431

Study on effects of swift heavy ion irradiation in cerium dioxide using synchrotron radiation X-ray absorption spectroscopy  

Microsoft Academic Search

In order to simulate the effects of high energy fission products on high-burnup UO2 nuclear fuel pellets, CeO2 thin films and bulk specimens were irradiated with 200MeV Xe ions. Effects of the irradiation were studied by using Extended X-ray Absorption Fine Structure (EXAFS) measurement and X-ray photoelectron spectroscopy (XPS) at synchrotron radiation facilities. The EXAFS spectra for the irradiated thin

H. Ohno; A. Iwase; D. Matsumura; Y. Nishihata; J. Mizuki; N. Ishikawa; Y. Baba; N. Hirao; T. Sonoda; M. Kinoshita

2008-01-01

432

Direct speciation of chromium in coal combustion by-products by X-ray absorption fine-structure spectroscopy  

Microsoft Academic Search

Chromium X-ray absorption fine-structure (XAFS) spectroscopy has been used to determine the relative amounts of Cr(VI) and Cr(III) in coal combustion by-products, principally fly-ash and bottom ash. The method, which is based on the relative heights of the pre-edge peaks for the different Cr oxidation states in X-ray absorption near-edge structure (XANES) spectra, can be used to speciate as little

Frank E Huggins; Mohammad Najih; Gerald P Huffman

1999-01-01

433

The experiment with the fast X-ray monitor (BRM) instrument onboard the CORONAS-PHOTON satellite  

NASA Astrophysics Data System (ADS)

The "Fast X-ray Monitor" (BRM) instrument operated in the complex of the scientific instruments onboard the CORONAS-PHOTON satellite from February 19, 2009, until December 1, 2009. The instrument is intended for the registration of the hard X-ray radiation of solar flares in the 20-600 keV energy range in six differential energy channels (20-30, 30