The MIT high resolution X-ray spectroscopy instruments on AXAF

NASA Technical Reports Server (NTRS)

Canizares, C. R.; Dewey, D.; Galton, E. B.; Markert, T. H.; Smith, Henry I.; Schattenburg, M. L.; Woodgate, B. E.; Jordan, S.

1992-01-01

The general design and performance characteristics of MIT's two dispersive spectrometers, the Bragg Crystal Spectrometer (BCS) and the High Energy Transmission Grating Spectrometer (HETG), now being developed for the Advanced X-ray Astrophysics Facility (AXAF), are described. Particular attention is given to the development of the critical technologies incorporated into these instruments, including BCS diffractors, imaging gas flow proportional counters, and grating elements for the HETG. The principal stages and the current status of the developments are reviewed.

Ultrafast X-Ray Spectroscopy of Conical Intersections

NASA Astrophysics Data System (ADS)

Neville, Simon P.; Chergui, Majed; Stolow, Albert; Schuurman, Michael S.

2018-06-01

Ongoing developments in ultrafast x-ray sources offer powerful new means of probing the complex nonadiabatically coupled structural and electronic dynamics of photoexcited molecules. These non-Born-Oppenheimer effects are governed by general electronic degeneracies termed conical intersections, which play a key role, analogous to that of a transition state, in the electronic-nuclear dynamics of excited molecules. Using high-level ab initio quantum dynamics simulations, we studied time-resolved x-ray absorption (TRXAS) and photoelectron spectroscopy (TRXPS) of the prototypical unsaturated organic chromophore, ethylene, following excitation to its S2(π π*) state. The TRXAS, in particular, is highly sensitive to all aspects of the ensuing dynamics. These x-ray spectroscopies provide a clear signature of the wave packet dynamics near conical intersections, related to charge localization effects driven by the nuclear dynamics. Given the ubiquity of charge localization in excited state dynamics, we believe that ultrafast x-ray spectroscopies offer a unique and powerful route to the direct observation of dynamics around conical intersections.

Solar X-Ray and Gamma-Ray Imaging Spectroscopy

NASA Astrophysics Data System (ADS)

Dennis, B. R.; Christe, S. D.; Shih, A. Y.; Holman, G. D.; Emslie, A. G.; Caspi, A.

2018-02-01

X-ray and gamma-ray Sun observations from a lunar-based observatory would provide unique information on solar atmosphere thermal and nonthermal processes. EUV and energetic neutral atom imaging spectroscopy would augment the scientific value.

What can be Learned from X-ray Spectroscopy Concerning Hot Gas in Local Bubble and Charge Exchange Processes?

NASA Technical Reports Server (NTRS)

Snowden, Steve

2007-01-01

What can be learned from x-ray spectroscopy in observing hot gas in local bubble and charge exchange processes depends on spectral resolution, instrumental grasp, instrumental energy band, signal-to-nose, field of view, angular resolution and observatory location. Early attempts at x-ray spectroscopy include ROSAT; more recently, astronomers have used diffuse x-ray spectrometers, XMM Newton, sounding rocket calorimeters, and Suzaku. Future observations are expected with calorimeters on the Spectrum Roentgen Gamma mission, and the Solar Wind Charge Exchange (SWCX). The Geospheric SWCX may provide remote sensing of the solar wind and magnetosheath and remote observations of solar CMEs moving outward from the sun.

X-ray echo spectroscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Shvyd'ko, Yuri V.

2016-09-01

X-ray echo spectroscopy, a counterpart of neutron spin-echo, was recently introduced [1] to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a point-like x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x-rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-meV and 0.02-meV ultra-high-resolution IXS applications (resolving power > 10^8) with broadband 5-13 meV dispersing systems will be presented featuring more than 1000-fold signal enhancement. The technique is general, applicable in different photon frequency domains. [1.] Yu. Shvyd'ko, Phys. Rev. Lett. 116, accepted (2016), arXiv:1511.01526.

X-ray absorption spectroscopy using a self-seeded soft X-ray free-electron laser

DOE PAGES

Kroll, Thomas; Kern, Jan; Kubin, Markus; ...

2016-09-19

X-ray free electron lasers (XFELs) enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L-edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. But, the required x-ray bandwidth is an order of magnitude narrower than that of self-amplified spontaneous emission (SASE), and additional monochromatization is needed. We compare L-edge x-ray absorption spectroscopy (XAS) of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source (LCLS) with a new technique based onmore » self-seeding of LCLS. We demonstrate how L-edge XAS can be performed using the self-seeding scheme without the need of an additional beam line monochromator. Lastly, we show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x-ray spectroscopy measurements.« less

X-ray absorption spectroscopy using a self-seeded soft X-ray free-electron laser

PubMed Central

Kroll, Thomas; Kern, Jan; Kubin, Markus; Ratner, Daniel; Gul, Sheraz; Fuller, Franklin D.; Löchel, Heike; Krzywinski, Jacek; Lutman, Alberto; Ding, Yuantao; Dakovski, Georgi L.; Moeller, Stefan; Turner, Joshua J.; Alonso-Mori, Roberto; Nordlund, Dennis L.; Rehanek, Jens; Weniger, Christian; Firsov, Alexander; Brzhezinskaya, Maria; Chatterjee, Ruchira; Lassalle-Kaiser, Benedikt; Sierra, Raymond G.; Laksmono, Hartawan; Hill, Ethan; Borovik, Andrew; Erko, Alexei; Föhlisch, Alexander; Mitzner, Rolf; Yachandra, Vittal K.; Yano, Junko; Wernet, Philippe; Bergmann, Uwe

2016-01-01

X-ray free electron lasers (XFELs) enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L-edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. However, the required x-ray bandwidth is an order of magnitude narrower than that of self-amplified spontaneous emission (SASE), and additional monochromatization is needed. Here we compare L-edge x-ray absorption spectroscopy (XAS) of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source (LCLS) with a new technique based on self-seeding of LCLS. We demonstrate how L-edge XAS can be performed using the self-seeding scheme without the need of an additional beam line monochromator. We show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x-ray spectroscopy measurements. PMID:27828320

EUV spectroscopy of high-redshift x-ray objects

NASA Astrophysics Data System (ADS)

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

2010-07-01

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.

STROBE-X: X-ray Timing & Spectroscopy on Dynamical Timescales from Microseconds to Years

NASA Astrophysics Data System (ADS)

Wilson-Hodge, Colleen A.; Ray, Paul S.; Maccarone, Thomas J.; Chakrabarty, Deepto; Gendreau, Keith C.; Arzoumanian, Zaven; Jenke, Peter; Ballantyne, David; Bozzo, Enrico; Brandt, Soren; Brenneman, Laura; Christophersen, Marc; DeRosa, Alessandra; Feroci, Marco; Goldstein, Adam; Hartmann, Dieter; Hernanz, Margarita; McDonald, Michael; Phlips, Bernard; Remillard, Ronald; Stevens, Abigail; Tomsick, John; Watts, Anna; Wood, Kent S.; Zane, Silvia; STROBE-X Collaboration

2018-01-01

We describe a probe-class mission concept that provides an unprecedented view of the X-ray sky, performing timing and 0.2-30 keV spectroscopy over timescales from microseconds to years. The Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) comprises three primary instruments. The first uses an array of lightweight optics (3-m focal length) that concentrate incident photons onto solid state detectors with CCD-level (85-130 eV) energy resolution, 100 ns time resolution, and low background rates to cover the 0.2-12 keV band. This technology is scaled up from NICER, with enhanced optics to take advantage of the longer focal length of STROBE-X. The second uses large-area collimated silicon drift detectors, developed for ESA's LOFT, to cover the 2-30 keV band. These two instruments each provide an order of magnitude improvement in effective area compared with its predecessor (NICER and RXTE, respectively). Finally, a sensitive sky monitor triggers pointed observations, provides high duty cycle, high time resolution, high spectral resolution monitoring of the X-ray sky with ~20 times the sensitivity of the RXTE ASM, and enables multi-wavelength and multi-messenger studies on a continuous, rather than scanning basis. We include updated instrument designs resulting from the GSFC IDL run in November 2017.For the first time, the broad coverage provides simultaneous study of thermal components, non-thermal components, iron lines, and reflection features from a single platform for accreting black holes at all scales. The enormous collecting area allows detailed studies of the dense matter equation of state using both thermal emission from rotation-powered pulsars and harder emission from X-ray burst oscillations. The combination of the wide-field monitor and the sensitive pointed instruments enables observations of potential electromagnetic counterparts to LIGO/Virgo and neutrino events. Extragalactic science, such as constraining bulk metalicity

EUV Spectroscopy of High-redshift X-ray Objects

NASA Astrophysics Data System (ADS)

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

2010-03-01

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 be lost to X-ray instruments operating at traditional ( 0.5-10 keV) and higher X-ray energies. There are precedents in other wavebands. For example, HST evolutionary studies will become largely the province of JWST. Despite the successes of EUVE, the ROSAT WFC, and the Chandra LETG, the EUV continues to be unappreciated and under-utilized, partly because of a preconception that absorption by neutral galactic Hydrogen in the ISM prevents any useful extragalactic measurements at all EUV wavelengths and, until recently, by a lack of a suitable enabling technology. Thus, if future planned X-ray missions (e.g., IXO, Gen-X) are optimized again for traditional X-ray energies, their performance (effective area, resolving power) will be cut off at ultrasoft X-ray energies or at best be radically reduced in the EUV. This opens up a critical gap in performance located right at short EUV wavelengths, where the 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 nano-laminate fabrication 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

High resolution X- and gamma-ray spectroscopy of cosmic X-ray sources

NASA Technical Reports Server (NTRS)

Lin, R. P.

1983-01-01

A high resolution X-ray spectrometer and large area phoswich detector were designed and co-aligned in a common elevation mounting in order to measure solar and cosmic X-ray and gamma ray emission in the 13 to 600 KeV energy range from a balloon. The instrument is described and results obtained for the Crab Nebula, the supernova remnant Cas A, and the Sun are discussed and analyzed.

AXSIS: Exploring the frontiers in attosecond X-ray science, imaging and spectroscopy.

PubMed

Kärtner, F X; Ahr, F; Calendron, A-L; Çankaya, H; Carbajo, S; Chang, G; Cirmi, G; Dörner, K; Dorda, U; Fallahi, A; Hartin, A; Hemmer, M; Hobbs, R; Hua, Y; Huang, W R; Letrun, R; Matlis, N; Mazalova, V; Mücke, O D; Nanni, E; Putnam, W; Ravi, K; Reichert, F; Sarrou, I; Wu, X; Yahaghi, A; Ye, H; Zapata, L; Zhang, D; Zhou, C; Miller, R J D; Berggren, K K; Graafsma, H; Meents, A; Assmann, R W; Chapman, H N; Fromme, P

2016-09-01

X-ray crystallography is one of the main methods to determine atomic-resolution 3D images of the whole spectrum of molecules ranging from small inorganic clusters to large protein complexes consisting of hundred-thousands of atoms that constitute the macromolecular machinery of life. Life is not static, and unravelling the structure and dynamics of the most important reactions in chemistry and biology is essential to uncover their mechanism. Many of these reactions, including photosynthesis which drives our biosphere, are light induced and occur on ultrafast timescales. These have been studied with high time resolution primarily by optical spectroscopy, enabled by ultrafast laser technology, but they reduce the vast complexity of the process to a few reaction coordinates. In the AXSIS project at CFEL in Hamburg, funded by the European Research Council, we develop the new method of attosecond serial X-ray crystallography and spectroscopy, to give a full description of ultrafast processes atomically resolved in real space and on the electronic energy landscape, from co-measurement of X-ray and optical spectra, and X-ray diffraction. This technique will revolutionize our understanding of structure and function at the atomic and molecular level and thereby unravel fundamental processes in chemistry and biology like energy conversion processes. For that purpose, we develop a compact, fully coherent, THz-driven atto-second X-ray source based on coherent inverse Compton scattering off a free-electron crystal, to outrun radiation damage effects due to the necessary high X-ray irradiance required to acquire diffraction signals. This highly synergistic project starts from a completely clean slate rather than conforming to the specifications of a large free-electron laser (FEL) user facility, to optimize the entire instrumentation towards fundamental measurements of the mechanism of light absorption and excitation energy transfer. A multidisciplinary team formed by laser

STROBE-X: X-ray Timing & Spectroscopy on Dynamical Timescales from Microseconds to Years

NASA Astrophysics Data System (ADS)

Wilson-Hodge, Colleen A.; Ray, Paul S.; Gendreau, Keith; Chakrabarty, Deepto; Feroci, Marco; Maccarone, Tom; Arzoumanian, Zaven; Remillard, Ronald A.; Wood, Kent; Griffith, Christopher; STROBE-X Collaboration

2017-01-01

We describe a proposed probe-class mission concept that will provide an unprecedented view of the X-ray sky, performing timing and spectroscopy over a broad band (0.2-30 keV) probing timescales from microseconds to years. The Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) comprises two primary instruments. The soft band (0.2-12 keV) will be covered by an array of lightweight optics (3-m focal length) that concentrate incident photons onto small solid state detectors with CCD-level (85-130 eV) energy resolution, 100 ns time resolution, and low background rates. This technology, fully developed for NICER, would be scaled up with enhanced optics to take advantage of the longer focal length of STROBE-X. The harder band (2 to at least 30 keV) would be covered by large-area collimated silicon drift detectors,developed for the European LOFT mission concept. Each instrument would provide an order of magnitude improvement in effective area compared with its predecessor (NICER in the soft band and RXTE in the hard band). A sensitive sky monitor would act as a trigger for pointed observations, provide high duty cycle, high time resolution, high spectral resolution monitoring of the X-ray sky with ~20 times the sensitivity of the RXTE ASM, and enable multi-wavelength and multi-messenger studies on a continuous, rather than scanning basis.The broad coverage will enable thermal components, non-thermal components, iron lines, and reflection features to be studied simultaneously from a single platform for the first time in accreting black holes at all scales. The enormous collecting area will enable studies of the dense matter equation of state using both soft thermal emission from rotation-powered pulsars and harder emission from X-ray burst oscillations. Revolutionary science, such as high quality spectroscopy of clusters of galaxies and unprecedented timing investigations of active galactic nuclei, would also be obtained.We describe the mission

The Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO)

NASA Technical Reports Server (NTRS)

White, Nicholas E.; Bookbinder, Jay; Petre, Robert; Smith, Randall; Ptak, Andrew; Tananbaum, Harvey; Garcia, Michael

2012-01-01

Following recommendations from the 2010 "New Worlds, New Horizons" (NWNH) report, the Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO) concept streamlines the International X-ray Observatory (IXO) mission to concentrate on the science objectives that are enabled by high-resolution spectroscopic capabilities. AXSIO will trace orbits close to the event horizon of black holes, measure black hole spin for tens of supermassive black holes (SMBH), use spectroscopy to characterize outflows and the environment of AGN during their peak activity, observe 5MBH out to redshift z=6, map bulk motions and turbulence in galaxy clusters, find the missing baryons in the cosmic web using background quasars, and observe the process of cosmic feedback where black holes and supernovae inject energy on galactic and intergalactic scales. These measurements are enabled by a 0.9 sq m collecting area at 1.25 keV, a micro calorimeter array providing high-resolution spectroscopic imaging and a deployable high efficiency grating spectrometer. AXSIO delivers a 30-fold increase in effective area for high resolution spectroscopy. The key simplifications are guided by recommendations in the NWNH panel report include a reduction in focal length from 20m to 10m, eliminating the extendable optical bench, and a reduction in the instrument complement from six to two, avoiding a movable instrument platform. A focus on spectroscopic science allows the spatial resolution requirement to be relaxed to 10 arc sec (with a 5 arc sec goal). These simplifications decrease the total mission cost to under the $2B cost to NASA recommended by NWNH. AXSIO will be available to the entire astronomical community with observing allocations based on peer-review.

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides

DOE PAGES

Ju, Guangxu; Highland, Matthew J.; Yanguas-Gil, Angel; ...

2017-03-21

Here, we describe an instrument that exploits the ongoing revolution in synchrotron sources, optics, and detectors to enable in situ studies of metal-organic vapor phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray methods. The system includes high-resolution positioning of the sample and detector including full rotations, an x-ray transparent chamber wall for incident and diffracted beam access over a wide angular range, and minimal thermal sample motion, giving the sub-micron positional stability and reproducibility needed for coherent x-ray studies. The instrument enables surface x-ray photon correlation spectroscopy, microbeam diffraction, and coherent diffraction imaging of atomic-scale surface and filmmore » structure and dynamics during growth, to provide fundamental understanding of MOVPE processes.« less

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides.

PubMed

Ju, Guangxu; Highland, Matthew J; Yanguas-Gil, Angel; Thompson, Carol; Eastman, Jeffrey A; Zhou, Hua; Brennan, Sean M; Stephenson, G Brian; Fuoss, Paul H

2017-03-01

We describe an instrument that exploits the ongoing revolution in synchrotron sources, optics, and detectors to enable in situ studies of metal-organic vapor phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray methods. The system includes high-resolution positioning of the sample and detector including full rotations, an x-ray transparent chamber wall for incident and diffracted beam access over a wide angular range, and minimal thermal sample motion, giving the sub-micron positional stability and reproducibility needed for coherent x-ray studies. The instrument enables surface x-ray photon correlation spectroscopy, microbeam diffraction, and coherent diffraction imaging of atomic-scale surface and film structure and dynamics during growth, to provide fundamental understanding of MOVPE processes.

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides

NASA Astrophysics Data System (ADS)

Ju, Guangxu; Highland, Matthew J.; Yanguas-Gil, Angel; Thompson, Carol; Eastman, Jeffrey A.; Zhou, Hua; Brennan, Sean M.; Stephenson, G. Brian; Fuoss, Paul H.

2017-03-01

We describe an instrument that exploits the ongoing revolution in synchrotron sources, optics, and detectors to enable in situ studies of metal-organic vapor phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray methods. The system includes high-resolution positioning of the sample and detector including full rotations, an x-ray transparent chamber wall for incident and diffracted beam access over a wide angular range, and minimal thermal sample motion, giving the sub-micron positional stability and reproducibility needed for coherent x-ray studies. The instrument enables surface x-ray photon correlation spectroscopy, microbeam diffraction, and coherent diffraction imaging of atomic-scale surface and film structure and dynamics during growth, to provide fundamental understanding of MOVPE processes.

MARXS: A Modular Software to Ray-trace X-Ray Instrumentation

NASA Astrophysics Data System (ADS)

Günther, Hans Moritz; Frost, Jason; Theriault-Shay, Adam

2017-12-01

To obtain the best possible scientific result, astronomers must understand the properties of the available instrumentation well. This is important both when designing new instruments and when using existing instruments close to the limits of their specified capabilities or beyond. Ray-tracing is a technique for numerical simulations where the path of many light rays is followed through the system to understand how individual system components influence the observed properties, such as the shape of the point-spread-function. In instrument design, such simulations can be used to optimize the performance. For observations with existing instruments, this helps to discern instrumental artefacts from a true signal. Here, we describe MARXS, a new python package designed to simulate X-ray instruments on satellites and sounding rockets. MARXS uses probability tracking of photons and has polarimetric capabilities.

Recent applications of hard x-ray photoelectron spectroscopy

DOE PAGES

Weiland, Conan; Rumaiz, Abdul K.; Pianetta, Piero; ...

2016-05-05

Recent applications of hard x-ray photoelectron spectroscopy (HAXPES) demonstrate its many capabilities in addition to several of its limitations. Examples are given, including measurement of buried interfaces and materials under in-situ or in-operando conditions, as well as measurements under x-ray standing-wave and resonant excitation. We also present physical considerations that differentiate HAXPES from photoemission measurements utilizing soft and ultraviolet x rays.

Insights into electron and ion acceleration and transport from x-ray and gamma-ray imaging spectroscopy

NASA Astrophysics Data System (ADS)

Hurford, Gordon J.; Krucker, Samuel

The previous solar maximum has featured high resolution imaging/spectroscopy observations at hard x-ray and gamma-ray energies by the Reuven Ramaty High Energy Solar/Spectroscopic Imager (RHESSI). Highlights of these observations will be reviewed, along with their impli-cations for our understanding of ion and electron acceleration and transport processes. The results to date have included new insights into the location of the acceleration region and the thick target model, a new appreciation of the significance of x-ray albedo, observation of coronal gamma-ray sources and their implications for electron trapping, and indications of differences in the acceleration and transport between electrons and ions. The role of RHESSI's observational strengths and weaknesses in determining the character of its scientific results will also be discussed and used to identify what aspects of the acceleration and transport processes must await the next generation of instrumentation. The extent to which new instrumentation now under development, such as Solar Orbiter/STIX, GRIPS, and FOXSI, can address these open issues will be outlined.

The Focal Plane Assembly for the Athena X-Ray Integral Field Unit Instrument

NASA Technical Reports Server (NTRS)

Jackson, B. D.; Van Weers, H.; van der Kuur, J.; den Hartog, R.; Akamatsu, H.; Argan, A.; Bandler, S. R.; Barbera, M.; Barret, D.; Bruijn, M. P.;

Observational techniques for solar flare gamma-rays, hard X-rays, and neutrons

NASA Technical Reports Server (NTRS)

Lin, Robert P.

1989-01-01

The development of new instrumentation and techniques for solar hard X-ray, gamma ray and neutron observations from spacecraft and/or balloon-borne platforms is examined. The principal accomplishments are: (1) the development of a two segment germanium detector which is near ideal for solar hard X-ray and gamma ray spectroscopy; (2) the development of long duration balloon flight techniques and associated instrumentation; and (3) the development of innovative new position sensitive detectors for hard X-ray and gamma rays.

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

PubMed Central

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

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

PAL-XFEL soft X-ray scientific instruments and X-ray optics: First commissioning results

NASA Astrophysics Data System (ADS)

Park, Sang Han; Kim, Minseok; Min, Changi-Ki; Eom, Intae; Nam, Inhyuk; Lee, Heung-Soo; Kang, Heung-Sik; Kim, Hyeong-Do; Jang, Ho Young; Kim, Seonghan; Hwang, Sun-min; Park, Gi-Soo; Park, Jaehun; Koo, Tae-Yeong; Kwon, Soonnam

2018-05-01

We report an overview of soft X-ray scientific instruments and X-ray optics at the free electron laser (FEL) of the Pohang Accelerator Laboratory, with selected first-commissioning results. The FEL exhibited a pulse energy of 200 μJ/pulse, a pulse width of <50 fs full width at half maximum, and an energy bandwidth of 0.44% at a photon energy of 850 eV. Monochromator resolving power of 10 500 was achieved. The estimated total time resolution between optical laser and X-ray pulses was <270 fs. A resonant inelastic X-ray scattering spectrometer was set up; its commissioning results are also reported.

Time-resolved X-ray spectroscopies of chemical systems: New perspectives

PubMed Central

Chergui, Majed

2016-01-01

The past 3–5 years have witnessed a dramatic increase in the number of time-resolved X-ray spectroscopic studies, mainly driven by novel technical and methodological developments. The latter include (i) the high repetition rate optical pump/X-ray probe studies, which have greatly boosted the signal-to-noise ratio for picosecond (ps) X-ray absorption spectroscopy studies, while enabling ps X-ray emission spectroscopy (XES) at synchrotrons; (ii) the X-ray free electron lasers (XFELs) are a game changer and have allowed the first femtosecond (fs) XES and resonant inelastic X-ray scattering experiments to be carried out; (iii) XFELs are also opening the road to the development of non-linear X-ray methods. In this perspective, I will mainly focus on the most recent technical developments and briefly address some examples of scientific questions that have been addressed thanks to them. I will look at the novel opportunities in the horizon. PMID:27376102

A Broadband X-Ray Imaging Spectroscopy with High-Angular Resolution: the FORCE Mission

NASA Technical Reports Server (NTRS)

Mori, Koji; Tsuru, Takeshi Go; Nakazawac, Kazuhiro; Ueda, Yoshihiro; Okajima, Takashi; Murakami, Hiroshi; Awaki, Hisamitsu; Matsumoto, Hironori; Fukazawai, Yasushi; Tsunemi, Hiroshi;

SUT-NANOTEC-SLRI beamline for X-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klysubun, Wantana; Kidkhunthod, Pinit; Tarawarakarn, Pongjakr

2017-04-04

The SUT-NANOTEC-SLRI beamline was constructed in 2012 as the flagship of the SUT-NANOTEC-SLRI Joint Research Facility for Synchrotron Utilization, co-established by Suranaree University of Technology (SUT), National Nanotechnology Center (NANOTEC) and Synchrotron Light Research Institute (SLRI). It is an intermediate-energy X-ray absorption spectroscopy (XAS) beamline at SLRI. The beamline delivers an unfocused monochromatic X-ray beam of tunable photon energy (1.25–10 keV). The maximum normal incident beam size is 13 mm (width) × 1 mm (height) with a photon flux of 3 × 10 8to 2 × 10 10 photons s -1(100 mA) -1varying across photon energies. Details of the beamlinemore » and XAS instrumentation are described. To demonstrate the beamline performance,K-edge XANES spectra of MgO, Al 2O 3, S 8, FeS, FeSO 4, Cu, Cu 2O and CuO, and EXAFS spectra of Cu and CuO are presented.« less

An instrument for 3D x-ray nano-imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holler, M.; Raabe, J.; Diaz, A.

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 amore » test object of copper interconnects of a microprocessor, a resolution of 53 nm is achieved.« less

Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kojima, Sadaoki, E-mail: kojima-s@ile.osaka-u.ac.jp, E-mail: sfujioka@ile.osaka-u.ac.jp; Ikenouchi, Takahito; Arikawa, Yasunobu

Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>10{sup 13} photons/shot) hard X-rays. However, high energy resolution (Δhv/hv < 0.1) is not achievable with a differential energy threshold (DET) X-ray spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolutionmore » than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO{sub 2} converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV.« less

A broadband x-ray imaging spectroscopy with high-angular resolution: the FORCE mission

NASA Astrophysics Data System (ADS)

Mori, Koji; Tsuru, Takeshi Go; Nakazawa, Kazuhiro; Ueda, Yoshihiro; Okajima, Takashi; Murakami, Hiroshi; Awaki, Hisamitsu; Matsumoto, Hironori; Fukazawa, Yasushi; Tsunemi, Hiroshi; Takahashi, Tadayuki; Zhang, William W.

2016-07-01

We are proposing FORCE (Focusing On Relativistic universe and Cosmic Evolution) as a future Japan-lead Xray observatory to be launched in the mid 2020s. Hitomi (ASTRO-H) possesses a suite of sensitive instruments enabling the highest energy-resolution spectroscopy in soft X-ray band, a broadband X-ray imaging spectroscopy in soft and hard X-ray bands, and further high energy coverage up to soft gamma-ray band. FORCE is the direct successor to the broadband X-ray imaging spectroscopy aspect of Hitomi (ASTRO-H) with significantly higher angular resolution. The current design of FORCE defines energy band pass of 1-80 keV with angular resolution of < 15 in half-power diameter, achieving a 10 times higher sensitivity above 10 keV compared to any previous missions with simultaneous soft X-ray coverage. Our primary scientific objective is to trace the cosmic formation history by searching for "missing black holes" in various mass-scales: "buried supermassive black holes (SMBHs)" (> 104 M⊙) residing in the center of galaxies in a cosmological distance, "intermediate-mass black holes" (102-104 M⊙) acting as the possible seeds from which SMBHs grow, and "orphan stellar-mass black holes" (< 102 M⊙) without companion in our Galaxy. In addition to these missing BHs, hunting for the nature of relativistic particles at various astrophysical shocks is also in our scope, utilizing the broadband X-ray coverage with high angular-resolution. FORCE are going to open a new era in these fields. The satellite is proposed to be launched with the Epsilon vehicle that is a Japanese current solid-fuel rocket. FORCE carries three identical pairs of Super-mirror and wide-band X-ray detector. The focal length is currently planned to be 10 m. The silicon mirror with multi-layer coating is our primary choice to achieve lightweight, good angular optics. The detector is a descendant of hard X-ray imager onboard Hitomi (ASTRO-H) replacing its silicon strip detector with SOI-CMOS silicon pixel

Mode-Locked Multichromatic X-Rays in a Seeded Free-Electron Laser for Single-Shot X-Ray Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiang, Dao; Ding, Yuantao; Raubenheimer, Tor

2012-05-10

We present the promise of generating gigawatt mode-locked multichromatic x rays in a seeded free-electron laser (FEL). We show that, by using a laser to imprint periodic modulation in electron beam phase space, a single-frequency coherent seed can be amplified and further translated to a mode-locked multichromatic output in an FEL. With this configuration the FEL output consists of a train of mode-locked ultrashort pulses which span a wide frequency gap with a series of equally spaced sharp lines. These gigawatt multichromatic x rays may potentially allow one to explore the structure and dynamics of a large number of atomicmore » states simultaneously. The feasibility of generating mode-locked x rays ranging from carbon K edge ({approx}284 eV) to copper L{sub 3} edge ({approx}931 eV) is confirmed with numerical simulation using the realistic parameters of the linac coherent light source (LCLS) and LCLS-II. We anticipate that the mode-locked multichromatic x rays in FELs may open up new opportunities in x-ray spectroscopy (i.e. resonant inelastic x-ray scattering, time-resolved scattering and spectroscopy, etc.).« less

Stimulated x-ray emission spectroscopy in transition metal complexes

DOE PAGES

Kroll, Thomas; Weninger, Clemens; Alonso-Mori, Roberto; ...

2018-03-27

We report the observation and analysis of the gain curve of amplified Kα X-ray emission from solutions of Mn(II) and Mn(VII) complexes using an X-ray free electron laser to create the 1s core-hole population inversion. We find spectra at amplification levels extending over four orders of magnitude until saturation. We observe bandwidths below the Mn 1s core-hole lifetime broadening in the onset of the stimulated emission. In the exponential amplification regime the resolution corrected spectral width of ~1.7 eV FWHM is constant over three orders of magnitude, pointing to the build-up of transform limited pulses of ~1fs duration. Driving the amplification into saturation leads to broadening and shift of the line. Importantly, the chemical sensitivity of the stimulated X-ray emission to the Mn oxidation state is preserved at power densities ofmore » $$\\sim10 20$$~W/cm 2 for the incoming X-ray pulses. Differences in signal sensitivity and spectral information compared to conventional (spontaneous) X-ray emission spectroscopy are discussed. Our findings build a baseline for nonlinear X-ray spectroscopy for a wide range of transition metal complexes in inorganic chemistry, catalysis and materials science.« less

Stimulated x-ray emission spectroscopy in transition metal complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroll, Thomas; Weninger, Clemens; Alonso-Mori, Roberto

We report the observation and analysis of the gain curve of amplified Kα X-ray emission from solutions of Mn(II) and Mn(VII) complexes using an X-ray free electron laser to create the 1s core-hole population inversion. We find spectra at amplification levels extending over four orders of magnitude until saturation. We observe bandwidths below the Mn 1s core-hole lifetime broadening in the onset of the stimulated emission. In the exponential amplification regime the resolution corrected spectral width of ~1.7 eV FWHM is constant over three orders of magnitude, pointing to the build-up of transform limited pulses of ~1fs duration. Driving the amplification into saturation leads to broadening and shift of the line. Importantly, the chemical sensitivity of the stimulated X-ray emission to the Mn oxidation state is preserved at power densities ofmore » $$\\sim10 20$$~W/cm 2 for the incoming X-ray pulses. Differences in signal sensitivity and spectral information compared to conventional (spontaneous) X-ray emission spectroscopy are discussed. Our findings build a baseline for nonlinear X-ray spectroscopy for a wide range of transition metal complexes in inorganic chemistry, catalysis and materials science.« less

Stimulated X-Ray Emission Spectroscopy in Transition Metal Complexes

NASA Astrophysics Data System (ADS)

Kroll, Thomas; Weninger, Clemens; Alonso-Mori, Roberto; Sokaras, Dimosthenis; Zhu, Diling; Mercadier, Laurent; Majety, Vinay P.; Marinelli, Agostino; Lutman, Alberto; Guetg, Marc W.; Decker, Franz-Josef; Boutet, Sébastien; Aquila, Andy; Koglin, Jason; Koralek, Jake; DePonte, Daniel P.; Kern, Jan; Fuller, Franklin D.; Pastor, Ernest; Fransson, Thomas; Zhang, Yu; Yano, Junko; Yachandra, Vittal K.; Rohringer, Nina; Bergmann, Uwe

2018-03-01

We report the observation and analysis of the gain curve of amplified K α x-ray emission from solutions of Mn(II) and Mn(VII) complexes using an x-ray free electron laser to create the 1 s core-hole population inversion. We find spectra at amplification levels extending over 4 orders of magnitude until saturation. We observe bandwidths below the Mn 1 s core-hole lifetime broadening in the onset of the stimulated emission. In the exponential amplification regime the resolution corrected spectral width of ˜1.7 eV FWHM is constant over 3 orders of magnitude, pointing to the buildup of transform limited pulses of ˜1 fs duration. Driving the amplification into saturation leads to broadening and a shift of the line. Importantly, the chemical sensitivity of the stimulated x-ray emission to the Mn oxidation state is preserved at power densities of ˜1020 W /cm2 for the incoming x-ray pulses. Differences in signal sensitivity and spectral information compared to conventional (spontaneous) x-ray emission spectroscopy are discussed. Our findings build a baseline for nonlinear x-ray spectroscopy for a wide range of transition metal complexes in inorganic chemistry, catalysis, and materials science.

Research relative to high energy astrophysics. [large area modular array of reflectors, X-ray spectroscopy, and thermal control

NASA Technical Reports Server (NTRS)

Gorenstein, P.

1984-01-01

Various parameters which affect the design of the proposed large area modular array of reflectors (LAMAR) are considered, including thermal control, high resolution X-ray spectroscopy, pointing control, and mirror performance. The LAMAR instrument is to be a shuttle-launched X-ray observatory to carry out cosmic X-ray investigations. The capabilities of LAMAR are enumerated. Angular resolution performance of the mirror module prototype was measured to be 30 sec of ARC for 50% of the power. The LAMAR thermal pre-collimator design concepts and test configurations are discussed in detail.

Instrument report: Planetary X-ray experiment

NASA Technical Reports Server (NTRS)

Anderson, K. A.

1972-01-01

Design studies for an X-ray experiment to investigate planetary magnetospheres using solid state detectors, or proportional counters are reported. The detectors, background counting rate, and leakage fluxes are discussed. It is concluded that the best choice of instruments appears to be two separate multiproportional counters for redundancy.

Lab-based ambient pressure X-ray photoelectron spectroscopy from past to present

NASA Astrophysics Data System (ADS)

Arble, Chris; Jia, Meng; Newberg, John T.

2018-05-01

Chemical interactions which occur at a heterogeneous interface between a gas and substrate are critical in many technological and natural processes. Ambient pressure X-ray photoelectron spectroscopy (AP-XPS) is a powerful spectroscopy tool that is inherently surface sensitive, elemental and chemical specific, with the ability to probe sample surfaces in the presence of a gas phase. In this review, we discuss the evolution of lab-based AP-XPS instruments, from the first development by Siegbahn and coworkers up through modern day systems. A comprehensive overview is given of heterogeneous experiments investigated to date via lab-based AP-XPS along with the different instrumental metrics that affect the quality of sample probing. We conclude with a discussion of future directions for lab-based AP-XPS, highlighting the efficacy for this in-demand instrument to continue to expand in its ability to significantly advance our understanding of surface chemical processes under in situ conditions in a technologically multidisciplinary setting.

Optimizing soft X-ray NEXAFS spectroscopy in the laboratory

NASA Astrophysics Data System (ADS)

Mantouvalou, I.; Jonas, A.; Witte, K.; Jung, R.; Stiel, H.; Kanngießer, B.

2017-05-01

Near edge X-ray absorption fine structure (NEXAFS) spectroscopy in the soft X-ray range is feasible in the laboratory using laser-produced plasma sources. We present a study using seven different target materials for optimized data analysis. The emission spectra of the materials with atomic numbers ranging from Z = 6 to Z = 79 show distinct differences, rendering the adapted selection of a suitable target material for specialized experiments feasible. For NEXAFS spectroscopy a 112.5 nm thick polyimide film is investigated as a reference exemplifying the superiority of quasi-continuum like emission spectra.

Resonant Polarization Spectroscopy for Hot X-ray Plasmas

DOE PAGES

Chen, Guo -Xin

2016-04-28

X-ray line polarization spectroscopy is a method of choice for probing hot plasma conditions. The precise roles of resonant structures in this method have not been realized and fully understood. With a sophisticated relativistic close coupling Dirac R-matrix calculation of polarized radiation of the quadrupole magnetic M2 line at 2.717 Å in Ba 46+, we revealed the nature of resonant structures in x-ray line polarization spectroscopy. We found that signatures with a heavy resonance forest imprinting on polarization may be used for a sensitive new spectroscopic method. The resonant polarization spectrum was used to determine or constrain the directional beammore » electron distribution of the laboratory Ba plasma. Lastly, our results provide a start of resonant polarization spectroscopy as a method for diagnostics of laboratory, fusion and astrophysical plasma source conditions.« less

Soft X-ray spectroscopy of nanoparticles by velocity map imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostko, O.; Xu, B.; Jacobs, M. I.

Velocity map imaging (VMI), a technique traditionally used to study chemical dynamics in the gas phase, is applied to study X-ray photoemission from aerosol nanoparticles. Soft X-rays from the Advanced Light Source synchrotron, probe a beam of nanoparticles, and the resulting photoelectrons are velocity mapped to obtain their kinetic energy distributions. A new design of the VMI spectrometer is described. The spectrometer is benchmarked by measuring vacuum ultraviolet photoemission from gas phase xenon and squalene nanoparticles followed by measurements using soft X-rays. It is demonstrated that the photoelectron distribution from X-ray irradiated squalene nanoparticles is dominated by secondary electrons. Bymore » scanning the photon energies and measuring the intensities of these secondary electrons, a near edge X-ray absorption fine structure (NEXAFS) spectrum is obtained. The NEXAFS technique is used to obtain spectra of aqueous nanoparticles at the oxygen K edge. By varying the position of the aqueous nanoparticle beam relative to the incident X-ray beam, evidence is presented such that the VMI technique allows for NEXAFS spectroscopy of water in different physical states. Finally, we discuss the possibility of applying VMI methods to probe liquids and solids via X-ray spectroscopy.« less

Soft X-ray spectroscopy of nanoparticles by velocity map imaging

DOE PAGES

Kostko, O.; Xu, B.; Jacobs, M. I.; ...

2017-05-05

Velocity map imaging (VMI), a technique traditionally used to study chemical dynamics in the gas phase, is applied to study X-ray photoemission from aerosol nanoparticles. Soft X-rays from the Advanced Light Source synchrotron, probe a beam of nanoparticles, and the resulting photoelectrons are velocity mapped to obtain their kinetic energy distributions. A new design of the VMI spectrometer is described. The spectrometer is benchmarked by measuring vacuum ultraviolet photoemission from gas phase xenon and squalene nanoparticles followed by measurements using soft X-rays. It is demonstrated that the photoelectron distribution from X-ray irradiated squalene nanoparticles is dominated by secondary electrons. Bymore » scanning the photon energies and measuring the intensities of these secondary electrons, a near edge X-ray absorption fine structure (NEXAFS) spectrum is obtained. The NEXAFS technique is used to obtain spectra of aqueous nanoparticles at the oxygen K edge. By varying the position of the aqueous nanoparticle beam relative to the incident X-ray beam, evidence is presented such that the VMI technique allows for NEXAFS spectroscopy of water in different physical states. Finally, we discuss the possibility of applying VMI methods to probe liquids and solids via X-ray spectroscopy.« less

A cosmic and solar X-ray and gamma-ray instrument for a scout launch

NASA Technical Reports Server (NTRS)

Forrest, D. J.; Vestrand, W. T.; Chupp, E. L.

1988-01-01

An overview is presented for a set of simple and robust X-ray and gamma ray instruments which have both cosmic and solar objectives. The primary solar scientific objective is the study of the beaming of energetic electrons and ions in solar flares. The instrument will measure spectra and polarization of flare emissions up to 10 MeV. At X-ray energies both the directly emitted flux and the reflected albedo flux will be measured with a complement of six X-ray sensors. Each of these detectors will have a different high Z filter selected to optimize both the energy resolution and high rate capabilities in the energy band 10 to 300 keV. At energies greater than 100 keV seven 7.6 x 7.6 cm NaI and a set of 30 concentric plastic scattering detectors will record the spectra and polarization of electron bremsstrahlung and nuclear gamma rays. All of the components of the instrument are in existence and have passed flight tests for earlier space missions. The instrument will use a spinning solar oriented Scout spacecraft. The NaI detectors will act as a self-modulating gamma ray detector for cosmic sources in a broad angular band which lies at 90 degrees to the Sun-Earth vector and hence will scan the entire sky in 6 months.

Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy below 100 eV: probing first-row transition-metal M-edges in chemical complexes.

PubMed

Wang, Hongxin; Young, Anthony T; Guo, Jinghua; Cramer, Stephen P; Friedrich, Stephan; Braun, Artur; Gu, Weiwei

2013-07-01

X-ray absorption and scattering spectroscopies involving the 3d transition-metal K- and L-edges have a long history in studying inorganic and bioinorganic molecules. However, there have been very few studies using the M-edges, which are below 100 eV. Synchrotron-based X-ray sources can have higher energy resolution at M-edges. M-edge X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) could therefore provide complementary information to K- and L-edge spectroscopies. In this study, M2,3-edge XAS on several Co, Ni and Cu complexes are measured and their spectral information, such as chemical shifts and covalency effects, are analyzed and discussed. In addition, M2,3-edge RIXS on NiO, NiF2 and two other covalent complexes have been performed and different d-d transition patterns have been observed. Although still preliminary, this work on 3d metal complexes demonstrates the potential to use M-edge XAS and RIXS on more complicated 3d metal complexes in the future. The potential for using high-sensitivity and high-resolution superconducting tunnel junction X-ray detectors below 100 eV is also illustrated and discussed.

The X-ray Astronomy Recovery Mission

NASA Astrophysics Data System (ADS)

Tashiro, M.; Kelley, R.

2017-10-01

On 25 March 2016, the Japanese 6th X-ray astronomical satellite ASTRO-H (Hitomi), launched on February 17, lost communication after a series of mishap in its attitude control system. In response to the mishap the X-ray astronomy community and JAXA analyzed the direct and root cause of the mishap and investigated possibility of a recovery mission with the international collaborator NASA and ESA. Thanks to great effort of scientists, agencies, and governments, the X-ray Astronomy Recovery Mission (XARM) are proposed. The recovery mission is planned to resume high resolution X-ray spectroscopy with imaging realized by Hitomi under the international collaboration in the shortest time possible, simply by focusing one of the main science goals of Hitomi Resolving astrophysical problems by precise high-resolution X-ray spectroscopy'. XARM will carry a 6 x 6 pixelized X-ray micro-calorimeter on the focal plane of an X-ray mirror assembly, and an aligned X-ray CCD camera covering the same energy band and wider field of view, but no hard X-ray or soft gamma-ray instruments are onboard. In this paper, we introduce the science objectives, mission concept, and schedule of XARM.

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)

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

2013-04-01

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 π-electron subsystem of CNTs which is accompanied by changes of the atomic and electronic structure of the filler during the encapsulating it inside CNTs.

X-Ray Spectroscopy of Photoionized Plasmas

NASA Technical Reports Server (NTRS)

Kallman, Tim

2008-01-01

Spectroscopy allows study of sources on small spatial scales, and can provide detailed diagnostic information about elemental abundances, temperature, density and gas dynamics. For compact sources such as accreting black holes in active galactic nuclei (AGN) and X-ray binaries X-ray spectra provide truly unique insight. Observations using Chandra and XMM have revealed components of gas in these systems which were previously unknown or poorly studied. Interpretation of these data presents modeling and analysis challenges, and requires an understanding of atomic physics, ionization and spectrum formation in a radiation-dominated environment. In this talk I will discuss examples, and how they have contributed to our understanding of accreting sources and the nearby gas.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langeveld, Willem G. J.; Gozani, Tsahi; Ryge, Peter

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 techniquesmore » 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 and 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, BaF{sub 2} and PbWO{sub 4}, as well as suitable photo-detectors, read-out and digitization electronics. We discuss high

X-ray absorption fine structure (XAFS) spectroscopy using synchrotron radiation

NASA Astrophysics Data System (ADS)

Shrivastava, B. D.

2012-05-01

The X-ray absorption fine structure (XAFS) spectra are best recorded when a highly intense beam of X-rays from a synchrotron is used along with a good resolution double crystal or curved crystal spectrometer and detectors like ionization chambers, scintillation counters, solid state detectors etc. Several synchrotrons around the world have X-ray beamlines dedicated specifically to XAFS spectroscopy. Fortunately, the Indian synchrotron (Indus-2) at Raja Ramanna Centre for Advanced Technology (RRCAT) at Indore has started operation. A dispersive type EXAFS beamline called BL-8 has been commissioned at this synchrotron and another beamline having double crystal monochromator (DCM) is going to be commissioned shortly. In Indian context, in order that more research workers use these beamlines, the study of XAFS spectroscopy using synchrotron radiation becomes important. In the present work some of the works done by our group on XAFS spectroscopy using synchrotron radiation have been described.

Ultrafast Time-Resolved Hard X-Ray Emission Spectroscopy on a Tabletop

NASA Astrophysics Data System (ADS)

Miaja-Avila, Luis; O'Neil, Galen C.; Joe, Young I.; Alpert, Bradley K.; Damrauer, Niels H.; Doriese, William B.; Fatur, Steven M.; Fowler, Joseph W.; Hilton, Gene C.; Jimenez, Ralph; Reintsema, Carl D.; Schmidt, Daniel R.; Silverman, Kevin L.; Swetz, Daniel S.; Tatsuno, Hideyuki; Ullom, Joel N.

2016-07-01

Experimental tools capable of monitoring both atomic and electronic structure on ultrafast (femtosecond to picosecond) time scales are needed for investigating photophysical processes fundamental to light harvesting, photocatalysis, energy and data storage, and optical display technologies. Time-resolved hard x-ray (>3 keV ) spectroscopies have proven valuable for these measurements due to their elemental specificity and sensitivity to geometric and electronic structures. Here, we present the first tabletop apparatus capable of performing time-resolved x-ray emission spectroscopy. The time resolution of the apparatus is better than 6 ps. By combining a compact laser-driven plasma source with a highly efficient array of microcalorimeter x-ray detectors, we are able to observe photoinduced spin changes in an archetypal polypyridyl iron complex [Fe (2 ,2'-bipyridine)3]2 + and accurately measure the lifetime of the quintet spin state. Our results demonstrate that ultrafast hard x-ray emission spectroscopy is no longer confined to large facilities and now can be performed in conventional laboratories with 10 times better time resolution than at synchrotrons. Our results are enabled, in part, by a 100- to 1000-fold increase in x-ray collection efficiency compared to current techniques.

Analytical characterization of a new mobile X-ray fluorescence and X-ray diffraction instrument combined with a pigment identification case study

NASA Astrophysics Data System (ADS)

Van de Voorde, Lien; Vekemans, Bart; Verhaeven, Eddy; Tack, Pieter; De Wolf, Robin; Garrevoet, Jan; Vandenabeele, Peter; Vincze, Laszlo

2015-08-01

A new, commercially available, mobile system combining X-ray diffraction and X-ray fluorescence has been evaluated which enables both elemental analysis and phase identification simultaneously. The instrument makes use of a copper or molybdenum based miniature X-ray tube and a silicon-Pin diode energy-dispersive detector to count the photons originating from the samples. The X-ray tube and detector are both mounted on an X-ray diffraction protractor in a Bragg-Brentano θ:θ geometry. The mobile instrument is one of the lightest and most compact instruments of its kind (3.5 kg) and it is thus very useful for in situ purposes such as the direct (non-destructive) analysis of cultural heritage objects which need to be analyzed on site without any displacement. The supplied software allows both the operation of the instrument for data collection and in-depth data analysis using the International Centre for Diffraction Data database. This paper focuses on the characterization of the instrument, combined with a case study on pigment identification and an illustrative example for the analysis of lead alloyed printing letters. The results show that this commercially available light-weight instrument is able to identify the main crystalline phases non-destructively, present in a variety of samples, with a high degree of flexibility regarding sample size and position.

High-Resolution Detector For X-Ray Diffraction

NASA Technical Reports Server (NTRS)

Carter, Daniel C.; Withrow, William K.; Pusey, Marc L.; Yost, Vaughn H.

1988-01-01

Proposed x-ray-sensitive imaging detector offers superior spatial resolution, counting-rate capacity, and dynamic range. Instrument based on laser-stimulated luminescence and reusable x-ray-sensitive film. Detector scans x-ray film line by line. Extracts latent image in film and simultaneously erases film for reuse. Used primarily for protein crystallography. Principle adapted to imaging detectors for electron microscopy and fluorescence spectroscopy and general use in astronomy, engineering, and medicine.

X-ray spectroscopy studies of nonradiative energy transfer processes in luminescent lanthanide materials

NASA Astrophysics Data System (ADS)

Pacold, Joseph I.

having a strong charge-transfer character. A second primary result comes from an an x-ray excited optical luminescence (XEOL) study that demonstrates, for the first time, that the high flux of modern synchrotron light sources can induce high fractional populations of excited states in trivalent lanthanide phosphors. In this work we have identified the leading-order nonlinear-response mechanism by drawing on strong similarities between XEOL and cathodoluminescence. These results establish the groundwork for studies that would allow deeper inquiry into energy-transfer mechanisms through time-resolved x-ray pump/optical-probe spectroscopies, through time-resolved x-ray emission spectroscopy, or through quantifying of higher-order nonlinear effects at further-enhanced fractional excitation levels. The above scientific results are augmented by a supporting effort in instrumental methodology. This includes the development of high-efficiency x-ray emission spectrometers and their use in collaborations to study pressure-induced changes in f-electron physics and to characterize the intermediate states that occur after photoexcitation of the photosystem-II protein.

High resolution X- and gamma-ray spectroscopy of solar flares

NASA Technical Reports Server (NTRS)

Lin, R. P.

1984-01-01

A balloon-borne X- and gamma-ray instrument was developed, fabricated, and flown. This instrument has the highest energy resolution of any instrument flown to date for measurements of solar and cosmic X-ray and gamma-ray emission in the 13 to 600 keV energy range. The purpose of the solar measurements was to study electron acceleration and solar flare energy release processes. The cosmic observations were to search for cyclotron line features from neutron stars and for low energy gamma-ray lines from nucleosynthesis. The instrument consists of four 4 cm diameter, 1.3 cm thick, planar intrinsic germanium detectors cooled by liquid nitrogen and surrounded by CsI and NaI anti-coincidence scintillation crystals. A graded z collimator limited the field of view to 3 deg x 6 deg and a gondola pointing system provided 0.3 deg pointing accuracy. A total of four flights were made with this instrument. Additional funding was obtained from NSF for the last three flights, which had primarily solar objectives. A detailed instrument description is given. The main scientific results and the data analysis are discussed. Current work and indications for future work are summarized. A bibliography of publications resulting from this work is given.

An upgraded x-ray spectroscopy diagnostic on MST.

PubMed

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

2010-10-01

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).

Photon statistics and speckle visibility spectroscopy with partially coherent X-rays.

PubMed

Li, Luxi; Kwaśniewski, Paweł; Orsi, Davide; Wiegart, Lutz; Cristofolini, Luigi; Caronna, Chiara; Fluerasu, Andrei

2014-11-01

A new approach is proposed for measuring structural dynamics in materials from multi-speckle scattering patterns obtained with partially coherent X-rays. Coherent X-ray scattering is already widely used at high-brightness synchrotron lightsources to measure dynamics using X-ray photon correlation spectroscopy, but in many situations this experimental approach based on recording long series of images (i.e. movies) is either not adequate or not practical. Following the development of visible-light speckle visibility spectroscopy, the dynamic information is obtained instead by analyzing the photon statistics and calculating the speckle contrast in single scattering patterns. This quantity, also referred to as the speckle visibility, is determined by the properties of the partially coherent beam and other experimental parameters, as well as the internal motions in the sample (dynamics). As a case study, Brownian dynamics in a low-density colloidal suspension is measured and an excellent agreement is found between correlation functions measured by X-ray photon correlation spectroscopy and the decay in speckle visibility with integration time obtained from the analysis presented here.

Cosmic X-ray physics

NASA Technical Reports Server (NTRS)

Mccammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1985-01-01

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument are described. UXT consists of three mechanically-collimated X-ray gas proportional counters with window/filter combinations which allow measurements in three energy bands, Be (80-110 eV), B (90-187 eV), and O (e84-532 eV). The Be band measurements provide an important constraint on local absorption of X-rays from the hot component of the local interstellar medium. Work has also continued on the development of a calorimetric detector for high-resolution spectroscopy in the 0.1 keV - 8keV energy range.

X-ray absorption spectroscopy: EXAFS (Extended X-ray Absorption Fine Structure) and XANES (X-ray Absorption Near Edge Structure)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alp, E.E.; Mini, S.M.; Ramanathan, M.

1990-04-01

The x-ray absorption spectroscopy (XAS) had been an essential tool to gather spectroscopic information about atomic energy level structure in the early decades of this century. It has also played an important role in the discovery and systematization of rare-earth elements. The discovery of synchrotron radiation in 1952, and later the availability of broadly tunable synchrotron based x-ray sources have revitalized this technique since the 1970's. The correct interpretation of the oscillatory structure in the x-ray absorption cross-section above the absorption edge by Sayers et. al. has transformed XAS from a spectroscopic tool to a structural technique. EXAFS (Extended X-raymore » Absorption Fine Structure) yields information about the interatomic distances, near neighbor coordination numbers, and lattice dynamics. An excellent description of the principles and data analysis techniques of EXAFS is given by Teo. XANES (X-ray Absorption Near Edge Structure), on the other hand, gives information about the valence state, energy bandwidth and bond angles. Today, there are about 50 experimental stations in various synchrotrons around the world dedicated to collecting x-ray absorption data from the bulk and surfaces of solids and liquids. In this chapter, we will give the basic principles of XAS, explain the information content of essentially two different aspects of the absorption process leading to EXAFS and XANES, and discuss the source and samples limitations.« less

X-ray astronomical spectroscopy

NASA Technical Reports Server (NTRS)

Holt, Stephen S.

1987-01-01

The contributions of the Goddard group to the history of X-ray astronomy are numerous and varied. One role that the group has continued to play involves the pursuit of techniques for the measurement and interpretation of the X-ray spectra of cosmic sources. The latest development is the selection of the X-ray microcalorimeter for the Advanced X-ray Astrophysics Facility (AXAF) study payload. This technology is likely to revolutionize the study of cosmic X-ray spectra.

X-ray Diffraction Gratings for Astrophysics

NASA Astrophysics Data System (ADS)

Paerels, Frits

2010-12-01

Over the past year, we have celebrated the tenth anniversary of the Chandra and XMM-Newton X-ray observatories. Both carry powerful, novel diffraction grating spectrometers, which have opened true X-ray spectroscopy for astrophysics. I will describe the design and operation of these instruments, as the background to some of the beautiful results they have produced. But these designs do not exhaust the versatility and essential simplicity of diffraction grating spectrometers, and I will discuss applications for the International X-ray Observatory IXO.

Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy below 100 eV: probing first-row transition-metal M-edges in chemical complexes

PubMed Central

Wang, Hongxin; Young, Anthony T.; Guo, Jinghua; Cramer, Stephen P.; Friedrich, Stephan; Braun, Artur; Gu, Weiwei

2013-01-01

X-ray absorption and scattering spectroscopies involving the 3d transition-metal K- and L-edges have a long history in studying inorganic and bioinorganic molecules. However, there have been very few studies using the M-edges, which are below 100 eV. Synchrotron-based X-ray sources can have higher energy resolution at M-edges. M-edge X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) could therefore provide complementary information to K- and L-edge spectroscopies. In this study, M 2,3-edge XAS on several Co, Ni and Cu complexes are measured and their spectral information, such as chemical shifts and covalency effects, are analyzed and discussed. In addition, M 2,3-edge RIXS on NiO, NiF2 and two other covalent complexes have been performed and different d–d transition patterns have been observed. Although still preliminary, this work on 3d metal complexes demonstrates the potential to use M-edge XAS and RIXS on more complicated 3d metal complexes in the future. The potential for using high-sensitivity and high-resolution superconducting tunnel junction X-ray detectors below 100 eV is also illustrated and discussed. PMID:23765304

Set of instruments for solar EUV and soft X-ray monitoring onboard satellite Coronas-Photon

NASA Astrophysics Data System (ADS)

Kotov, Yury; Kochemasov, Alexey; Kuzin, Sergey; Kuznetsov, Vladimir; Sylwester, Janusz; Yurov, Vitaly

Coronas-Photon mission is the third satellite of the Russian Coronas program on solar activity observation. The main goal of the "Coronas-Photon" is the study of solar hard electromagnetic radiation in the wide energy range from UV up to high energy gamma-radiation (2000MeV). Scientific payload for solar radiation observation consists of three types of instruments: Monitors (Natalya-2M, Konus-RF, RT-2, Penguin-M, BRM, PHOKA, Sphin-X, SOKOL spectral and timing measurements of full solar disk radiation have timing in flare/burst mode up to one msec. Instruments Natalya-2M, Konus-RF, RT-2 will cover the wide energy range of hard X-rays and soft gamma-rays (15keV to 2000MeV) and will together constitute the largest area detectors ever used for solar observations. Detectors of gamma-ray monitors are based on structured inorganic scintillators. For X-ray and EUV monitors the scintillation phoswich detectors, gas proportional counter, CdZnTe assembly and filter-covered Si-diodes are used. Telescope-spectrometer TESIS for imaging solar spectroscopy in X-rays has angular resolution up to 1arcsec in three spectral lines. Satellite platform and scientific payload is under construction to be launched in autumn 2008. Satellite orbit is circular with initial height 550km and inclination 82.5degrees. Accuracy of the spacecraft orientation to the Sun is better 3arcmin. In the report the capability of PHOKA, SphinX, SOKOL and TESIS as well as the observation program are described and discussed.

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

NASA Astrophysics Data System (ADS)

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

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

Effect of X-ray flux on polytetrafluoroethylene in X-ray photoelectron spectroscopy

NASA Technical Reports Server (NTRS)

Wheeler, D. R.; Pepper, S. V.

1982-01-01

The effect of the X-ray flux in X-ray photoelectron spectroscopy (STAT) on the constitution of the polytetrafluoroethylene (PTFE) surface has been examined. The radiation dose rate for our specimen was about 10 to the 7th rad/s. The structure, magnitude and binding energy of the C(1s) and F(1s) features of the XPS spectrum and the mass spectrum of gaseous species evolved during irradiation are observed. The strong time dependence of these signals over a period of several hours indicated that the surface constitution of PTFE is greatly affected by this level of radiation dose. The results are consistent with the development of a heavily cross-linked or branched structure in the PTFE surface region and the evolution of short chain fragments into the gas phase.

Kinoform optics applied to X-ray photon correlation spectroscopy.

PubMed

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

2010-05-01

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

Soft x-ray spectroscopy of high pressure liquid.

PubMed

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; Macdougall, James; Pepper, John; Armitage, Kevin; Borsos, Jason; Knauss, Kevin G; Lee, Namhey; Allézy, Arnaud; Gilbert, Benjamin; MacDowell, Alastair A; Liu, Yi-Sheng; Glans, Per-Anders; Sun, Xuhui; Chao, Weilun; Guo, Jinghua

2018-01-01

We describe a new experimental technique that allows for soft x-ray spectroscopy studies (∼100-1000 eV) of high pressure liquid (∼100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3 N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3 N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3 N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length of the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3 N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3 N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (∼350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.

Soft x-ray spectroscopy of high pressure liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

Soft x-ray spectroscopy of high pressure liquid

DOE PAGES

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; ...

2018-01-01

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

VLF and X-ray Instruments for Stratospheric Balloons: ABOVE2 and EPEx

NASA Astrophysics Data System (ADS)

Cully, C. M.; Galts, D.; Patrick, M.; Duffin, C.; Jang, A. C.; Pitzel, J.; Trumpour, T.; McCarthy, M.; Milling, D. K.

2017-12-01

The ABOVE2 (2016) and EPEx (2018) stratospheric balloon missions are designed to study energetic electrons precipitating from the radiation belts into the atmosphere. The payloads include instruments that measure Very Low Frequency (VLF) magnetic and electric fields, and bremsstrahlung X-rays. The ABOVE2 VLF instrument is an FPGA-based design with >200 kHz sampling rates, sub-microsecond timing accuracy and onboard spectral processing, designed in a Cubesat-friendly format. The EPEx X-ray instrument is a hard X-ray imaging system, also in a Cubesat-friendly format, incorporating a commercially-available Cadmium-Zinc-Telluride module. The imager is sufficiently lightweight that we can launch it on-demand with low-volume latex balloons. I will discuss the design and performance of both instruments, and present data from the ABOVE2 flights.

Second International Workshop on Ambient Pressure X-ray Photoelectron Spectroscopy

DOE PAGES

Bluhm, Hendrik; Crumlin, Ethan J.

2016-05-03

The Second International Workshop on Ambient Pressure X-ray Photoelectron Spectroscopy (APXPS) was held at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, CA, from December 7-9, 2015. It brought together more than 100 participants from 17 countries. The workshop followed the inaugural meeting at the French synchrotron SOLEIL in December 2014, which was organized by François Rochet. The strong interest in these workshops reflects the growth of the APXPS community over the last decade, with instruments now operational at more than 12 synchrotrons around the world (see SRN, Vol. 27, No. 2, pp. 14–23 (2014)), and a steady increase in themore » number of laboratory instruments. Finally, APXPS has established itself as an important method for the investigation of surfaces and interfaces under in situ and operando conditions, including liquid/vapor and liquid/solid interfaces.« less

Soft X-ray spectroscopy of transition metal compounds: a theoretical perspective

NASA Astrophysics Data System (ADS)

Bokarev, S. I.; Hilal, R.; Aziz, S. G.; Kühn, O.

2017-01-01

To date, X-ray spectroscopy has become a routine tool that can reveal highly local and element-specific information on the electronic structure of atoms in complex environments. Here, we report on the development of an efficient and versatile theoretical methodology for the treatment of soft X-ray spectra of transition metal compounds based on the multi-configurational self-consistent field electronic structure theory. A special focus is put on the L-edge photon-in/photon-out and photon-in/electron-out processes, i.e. X-ray absorption, resonant inelastic scattering, partial fluorescence yield, and photoelectron spectroscopy, all treated on the same theoretical footing. The investigated systems range from small prototypical coordination compounds and catalysts to aggregates of biomolecules.

X-Ray spectroscopy of cooling flows

NASA Technical Reports Server (NTRS)

Prestwich, Andrea

1996-01-01

Cooling flows in clusters of galaxies occur when the cooling time of the gas is shorter than the age of the cluster; material cools and falls to the center of the cluster potential. Evidence for short X-ray cooling times comes from imaging studies of clusters and X-ray spectroscopy of a few bright clusters. Because the mass accretion rate can be high (a few 100 solar mass units/year) the mass of material accumulated over the lifetime of a cluster can be as high as 10(exp 12) solar mass units. However, there is little evidence for this material at other wavelengths, and the final fate of the accretion material is unknown. X-ray spectra obtained with the Einstein SSS show evidence for absorption; if confirmed this result would imply that the accretion material is in the form of cool dense clouds. However ice on the SSS make these data difficult to interpret. We obtained ASCA spectra of the cooling flow cluster Abell 85. Our primary goals were to search for multi-temperature components that may be indicative of cool gas; search for temperature gradients across the cluster; and look for excess absorption in the cooling region.

A reaction cell for ambient pressure soft x-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Castán-Guerrero, C.; Krizmancic, D.; Bonanni, V.; Edla, R.; Deluisa, A.; Salvador, F.; Rossi, G.; Panaccione, G.; Torelli, P.

2018-05-01

We present a new experimental setup for performing X-ray Absorption Spectroscopy (XAS) in the soft X-ray range at ambient pressure. The ambient pressure XAS setup is fully compatible with the ultra high vacuum environment of a synchrotron radiation spectroscopy beamline end station by means of ultrathin Si3N4 membranes acting as windows for the X-ray beam and seal of the atmospheric sample environment. The XAS detection is performed in total electron yield (TEY) mode by probing the drain current from the sample with a picoammeter. The high signal/noise ratio achievable in the TEY mode, combined with a continuous scanning of the X-ray energies, makes it possible recording XAS spectra in a few seconds. The first results show the performance of this setup to record fast XAS spectra from sample surfaces exposed at atmospheric pressure, even in the case of highly insulating samples. The use of a permanent magnet inside the reaction cell enables the measurement of X-ray magnetic circular dichroism at ambient pressure.

The Athena X-ray Integral Field Unit (X-IFU)

NASA Astrophysics Data System (ADS)

Pajot, F.; Barret, D.; Lam-Trong, T.; den Herder, J.-W.; Piro, L.; Cappi, M.; Huovelin, J.; Kelley, R.; Mas-Hesse, J. M.; Mitsuda, K.; Paltani, S.; Rauw, G.; Rozanska, A.; Wilms, J.; Barbera, M.; Douchin, F.; Geoffray, H.; den Hartog, R.; Kilbourne, C.; Le Du, M.; Macculi, C.; Mesnager, J.-M.; Peille, P.

2018-04-01

The X-ray Integral Field Unit (X-IFU) of the Advanced Telescope for High-ENergy Astrophysics (Athena) large-scale mission of ESA will provide spatially resolved high-resolution X-ray spectroscopy from 0.2 to 12 keV, with 5^' ' } pixels over a field of view of 5 arc minute equivalent diameter and a spectral resolution of 2.5 eV (FWHM) up to 7 keV. The core scientific objectives of Athena drive the main performance parameters of the X-IFU. We present the current reference configuration of the X-IFU, and the key issues driving the design of the instrument.

Novel applications of X-ray photoelectron spectroscopy on unsupported nanoparticles

NASA Astrophysics Data System (ADS)

Kostko, Oleg; Xu, Bo; Jacobs, Michael I.; Ahmed, Musahid

X-ray photoelectron spectroscopy (XPS) is a powerful technique for chemical analysis of surfaces. We will present novel results of XPS on unsupported, gas-phase nanoparticles using a velocity-map imaging (VMI) spectrometer. This technique allows for probes of both the surfaces of nanoparticles via XPS as well as their interiors via near edge X-ray absorption fine structure (NEXAFS) spectroscopy. A recent application of this technique has confirmed that arginine's guanidinium group exists in a protonated state even in strongly basic solution. Moreover, the core-level photoelectron spectroscopy can provide information on the effective attenuation length (EAL) of low kinetic energy electrons. This contradictory value is important for determining the probing depth of XPS and in photolithography. A new method for determining EALs will be presented.

Microreactor Cells for High-Throughput X-ray Absorption Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beesley, Angela; Tsapatsaris, Nikolaos; Weiher, Norbert

2007-01-19

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 fullymore » automated HT-XAS technology based on existing industry standards is feasible and useful for the rapid elucidation of geometric and electronic structure of materials.« less

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

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

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 α 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.

Feasibility of Valence-to-Core X-ray Emission Spectroscopy for Tracking Transient Species

DOE PAGES

March, Anne Marie; Assefa, Tadesse A.; Bressler, Christian; ...

2015-02-09

X-ray spectroscopies, when combined in laser-pump, X-ray-probe measurement schemes, can be powerful tools for tracking the electronic and geometric structural changes that occur during the course of a photoinitiated chemical reaction. X-ray absorption spectroscopy (XAS) is considered an established technique for such measurements, and X-ray emission spectroscopy (XES) of the strongest core-to-core emission lines (Kα and Kβ) is now being utilized. Flux demanding valence-to-core XES promises to be an important addition to the time-resolved spectroscopic toolkit. Here In this paper we present measurements and density functional theory calculations on laser-excited, solution-phase ferrocyanide that demonstrate the feasibility of valence-to-core XES formore » time-resolved experiments. Lastly, we discuss technical improvements that will make valence-to-core XES a practical pump–probe technique.« less

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

Code of Federal Regulations, 2010 CFR

2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false X-ray, major instrument, fluoroscope, or... INSTITUTIONAL MANAGEMENT CUSTODY Searches of Housing Units, Inmates, and Inmate Work Areas § 552.13 X-ray, major... reasons only, with the inmate's consent. (b) The institution physician may authorize use of an X-ray for...

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

Code of Federal Regulations, 2013 CFR

2013-07-01

... 28 Judicial Administration 2 2013-07-01 2013-07-01 false X-ray, major instrument, fluoroscope, or... INSTITUTIONAL MANAGEMENT CUSTODY Searches of Housing Units, Inmates, and Inmate Work Areas § 552.13 X-ray, major... reasons only, with the inmate's consent. (b) The institution physician may authorize use of an X-ray for...

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

Code of Federal Regulations, 2014 CFR

2014-07-01

... 28 Judicial Administration 2 2014-07-01 2014-07-01 false X-ray, major instrument, fluoroscope, or... INSTITUTIONAL MANAGEMENT CUSTODY Searches of Housing Units, Inmates, and Inmate Work Areas § 552.13 X-ray, major... reasons only, with the inmate's consent. (b) The institution physician may authorize use of an X-ray for...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

... 28 Judicial Administration 2 2011-07-01 2011-07-01 false X-ray, major instrument, fluoroscope, or... INSTITUTIONAL MANAGEMENT CUSTODY Searches of Housing Units, Inmates, and Inmate Work Areas § 552.13 X-ray, major... reasons only, with the inmate's consent. (b) The institution physician may authorize use of an X-ray for...

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

Code of Federal Regulations, 2012 CFR

2012-07-01

... 28 Judicial Administration 2 2012-07-01 2012-07-01 false X-ray, major instrument, fluoroscope, or... INSTITUTIONAL MANAGEMENT CUSTODY Searches of Housing Units, Inmates, and Inmate Work Areas § 552.13 X-ray, major... reasons only, with the inmate's consent. (b) The institution physician may authorize use of an X-ray for...

Ultrafast X-Ray Absorption Spectroscopy of Isochorically Heated Warm Dense Matter

NASA Astrophysics Data System (ADS)

Engelhorn, Kyle Craig

This dissertation will present a series of new tools, together with new techniques, focused on the understanding of warm and dense matter. We report on the development of a high time resolution and high detection efficiency x-ray camera. The camera is integrated with a short pulse laser and an x-ray beamline at the Advanced Light Source synchrotron. This provides an instrument for single shot, broadband x-ray absorption spectroscopy of warm and dense matter with 2 picosecond time resolution. Warm and dense matter is created by isochorically heating samples of known density with an ultrafast optical laser pulse, and X-ray absorption spectroscopy probes the unoccupied electronic density of states before the onset of hydrodynamic expansion and electron-ion equilibrium is reached. Measured spectra from a variety of materials are compared with first principle molecular dynamics and density functional theory calculations. In heated silicon dioxide spectra, two novel pre-edge features are observed, a peak below the band gap and absorption within the band gap, while a reduction was observed in the features above the edge. From consideration of the calculated spectra, the peak below the gap is attributed to valence electrons that have been promoted to the conduction band, the absorption within the gap is attributed to broken Si-O bonds, and the reduction above the edge is attributed to an elevated ionic temperature. In heated copper spectra, a time-dependent shift and broadening of the absorption edge are observed, consistent with and elevated electron temperature. The temporal evolution of the electronic temperature is accurately determined by fitting the measured spectra with calculated spectra. The electron-ion equilibration is studied with a two-temperature model. In heated nickel spectra, a shift of the absorption edge is observed. This shift is found to be inconsistent with calculated spectra and independent of incident laser fluence. A shift of the chemical potential

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

NASA Astrophysics Data System (ADS)

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

2013-03-01

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

Extracting chemical information from high-resolution Kβ X-ray emission spectroscopy

NASA Astrophysics Data System (ADS)

Limandri, S.; Robledo, J.; Tirao, G.

2018-06-01

High-resolution X-ray emission spectroscopy allows studying the chemical environment of a wide variety of materials. Chemical information can be obtained by fitting the X-ray spectra and observing the behavior of some spectral features. Spectral changes can also be quantified by means of statistical parameters calculated by considering the spectrum as a probability distribution. Another possibility is to perform statistical multivariate analysis, such as principal component analysis. In this work the performance of these procedures for extracting chemical information in X-ray emission spectroscopy spectra for mixtures of Mn2+ and Mn4+ oxides are studied. A detail analysis of the parameters obtained, as well as the associated uncertainties is shown. The methodologies are also applied for Mn oxidation state characterization of double perovskite oxides Ba1+xLa1-xMnSbO6 (with 0 ≤ x ≤ 0.7). The results show that statistical parameters and multivariate analysis are the most suitable for the analysis of this kind of spectra.

Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics

PubMed Central

Picón, A.; Lehmann, C. S.; Bostedt, C.; Rudenko, A.; Marinelli, A.; Osipov, T.; Rolles, D.; Berrah, N.; Bomme, C.; Bucher, M.; Doumy, G.; Erk, B.; Ferguson, K. R.; Gorkhover, T.; Ho, P. J.; Kanter, E. P.; Krässig, B.; Krzywinski, J.; Lutman, A. A.; March, A. M.; Moonshiram, D.; Ray, D.; Young, L.; Pratt, S. T.; Southworth, S. H.

2016-01-01

New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Particularly, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. Here we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ions during the fragmentation of XeF2 molecules following X-ray absorption at the Xe site. PMID:27212390

Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics

DOE PAGES

Picón, A.; Lehmann, C. S.; Bostedt, C.; ...

2016-05-23

New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Specifically, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. In this paper, we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ionsmore » during the fragmentation of XeF 2 molecules following X-ray absorption at the Xe site.« less

Hetero-site-specific X-ray pump-probe spectroscopy for femtosecond intramolecular dynamics.

PubMed

Picón, A; Lehmann, C S; Bostedt, C; Rudenko, A; Marinelli, A; Osipov, T; Rolles, D; Berrah, N; Bomme, C; Bucher, M; Doumy, G; Erk, B; Ferguson, K R; Gorkhover, T; Ho, P J; Kanter, E P; Krässig, B; Krzywinski, J; Lutman, A A; March, A M; Moonshiram, D; Ray, D; Young, L; Pratt, S T; Southworth, S H

2016-05-23

New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond X-ray pulses, opening the possibility of performing ultrafast studies of X-ray-induced phenomena. Particularly, the experimental realization of hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is of special interest, in which an X-ray pump pulse is absorbed at one site within a molecule and an X-ray probe pulse follows the X-ray-induced dynamics at another site within the same molecule. Here we show experimental evidence of a hetero-site pump-probe signal. By using two-colour 10-fs X-ray pulses, we are able to observe the femtosecond time dependence for the formation of F ions during the fragmentation of XeF2 molecules following X-ray absorption at the Xe site.

Coherent Multidimensional Core Spectroscopy of Molecules with Multiple X-ray pulses

NASA Astrophysics Data System (ADS)

Mukamel, Shaul

2017-04-01

Multidimensional spectroscopy uses sequences of optical pulses to study dynamical processes in complex molecules through correlation plots involving several time delay periods. Extensions of these techniques to the x-ray regime will be discussed. Ultrafast nonlinear x-ray spectroscopy is made possible by newly developed free electron laser and high harmonic generation sources. The attosecond duration of X-ray pulses and the atomic selectivity of core X-ray excitations offer a uniquely high spatial and temporal resolution. We demonstrate how stimulated Raman detection of an X-ray probe may be used to monitor the phase and dynamics of the nonequilibrium valence electronic state wavepacket created by e.g. photoexcitation, photoionization and Auger processes. Spectroscopy of multiplecore excitations provides a new window into electron correlations. Applications will be presented to long-range charge transfer in proteins and to excitation energy transfer in porphyrin arrays. Conical intersections (CoIn) dominate the pathways and outcomes of virtually all photophysical and photochemical molecular processes. Despite extensive experimental and theoretical effort CoIns have not been directly observed yet and the experimental evidence is being inferred from fast reaction rates and some vibrational signatures. Novel ultrafast X ray probes for these processes will be presented. Short X-ray pulses can directly detect the passage through a CoIn with the adequate temporal and spectral sensitivity. The technique is based on a coherent Raman process that employs a composite femtosecond/attosecond X-ray pulse to directly detect the electronic coherences (rather than populations) that are generated as the system passes through the CoIn. Streaking of time-resolved photoelectron spectroscopy (TRPES) signals offers another powerful window into the joint electronic/vibrational dynamics at concial intersections. Strong coupling of molecules to the vacuum field of micro cavities can modify

Elemental-sensitive Detection of the Chemistry in Batteries through Soft X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering.

PubMed

Wu, Jinpeng; Sallis, Shawn; Qiao, Ruimin; Li, Qinghao; Zhuo, Zengqing; Dai, Kehua; Guo, Zixuan; Yang, Wanli

2018-04-17

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid based on volatile solar and wind sources. The pressing demand of developing high-performance electrochemical energy storage solutions, i.e., batteries, relies on both fundamental understanding and practical developments from both the academy and industry. The formidable challenge of developing successful battery technology stems from the different requirements for different energy-storage applications. Energy density, power, stability, safety, and cost parameters all have to be balanced in batteries to meet the requirements of different applications. Therefore, multiple battery technologies based on different materials and mechanisms need to be developed and optimized. Incisive tools that could directly probe the chemical reactions in various battery materials are becoming critical to advance the field beyond its conventional trial-and-error approach. Here, we present detailed protocols for soft X-ray absorption spectroscopy (sXAS), soft X-ray emission spectroscopy (sXES), and resonant inelastic X-ray scattering (RIXS) experiments, which are inherently elemental-sensitive probes of the transition-metal 3d and anion 2p states in battery compounds. We provide the details on the experimental techniques and demonstrations revealing the key chemical states in battery materials through these soft X-ray spectroscopy techniques.

The X-ray Spectrometer - A cryogenic instrument on the Advanced X-ray Astrophysics Facility

NASA Technical Reports Server (NTRS)

Breon, Susan R.; Hopkins, Richard A.; Nieczkoski, Stephen J.

1991-01-01

The X-ray Spectrometer (XRS) is an instrument on the Advanced X-ray Astrophysics Facility (AXAF), the third of NASA's Great Observatories scheduled for launch in 1998. The XRS detectors have a resolution of approximately 10 eV over the range 0.3 - 10 keV. To achieve this resolution, the detectors are maintained at or below 0.1 Kelvin using an adiabatic demagnetization refrigerator inside a superfluid helium dewar. In addition, split-Stirling-cycle mechanical coolers are used to extend the anticipated on-orbit helium lifetime to a minimum of 4 years. This paper describes the challenges of developing this hybrid cryogenic system and presents an overview of the current design of the system.

Probing molecular dynamics in solution with x-ray valence-to-core spectroscopy

NASA Astrophysics Data System (ADS)

Doumy, Gilles; March, Anne Marie; Tu, Ming-Feng; Al Haddad, Andre; Southworth, Stephen; Young, Linda; Walko, Donald; Bostedt, Christoph

2017-04-01

Hard X-ray spectroscopies are powerful tools for probing the electronic and geometric structure of molecules in complex or disordered systems and have been particularly useful for studying molecules in the solution phase. They are element specific, sensitive to the electronic structure and the local arrangements of surrounding atoms of the element being selectively probed. When combined in a pump-probe scheme with ultrafast lasers, X-ray spectroscopies can be used to track the evolution of structural changes that occur after photoexcitation. Efficient use of hard x-ray radiation coming from high brilliance synchrotrons and upcoming high repetition rate X-ray Free Electron Lasers requires MHz repetition rate lasers and data acquisition systems. High information content Valence-to-Core x-ray emission is directly sensitive to the molecular orbitals involved in photochemistry. We report on recent progress towards fully enabling this photon-hungry technique for the study of time-resolved molecular dynamics, including efficient detection and use of polychromatic x-ray micro-probe at the Advanced Photon Source. Work was supported by the U.S. Department of Energy, Office of Science, Chemical Sciences, Geosciences, and Biosciences Division.

Future prospects for high resolution X-ray spectrometers

NASA Technical Reports Server (NTRS)

Canizares, C. R.

1981-01-01

Capabilities of the X-ray spectroscopy payloads were compared. Comparison of capabilities of AXAF in the context of the science to be achieved is reported. The Einstein demonstrated the tremendous scientific power of spectroscopy to probe deeply the astrophysics of all types of celestial X-ray source. However, it has limitations in sensitivity and resolution. Each of the straw man instruments has a sensitivity that is at least an order of magnitude better than that of the Einstein FPSC. The AXAF promises powerful spectral capability.

New developments in high pressure x-ray spectroscopy beamline at High Pressure Collaborative Access Team

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Y. M., E-mail: yxiao@carnegiescience.edu; Chow, P.; Boman, G.

The 16 ID-D (Insertion Device - D station) beamline of the High Pressure Collaborative Access Team at the Advanced Photon Source is dedicated to high pressure research using X-ray spectroscopy techniques typically integrated with diamond anvil cells. The beamline provides X-rays of 4.5-37 keV, and current available techniques include X-ray emission spectroscopy, inelastic X-ray scattering, and nuclear resonant scattering. The recent developments include a canted undulator upgrade, 17-element analyzer array for inelastic X-ray scattering, and an emission spectrometer using a polycapillary half-lens. Recent development projects and future prospects are also discussed.

REDSoX: Monte-Carlo ray-tracing for a soft x-ray spectroscopy polarimeter

NASA Astrophysics Data System (ADS)

Günther, Hans M.; Egan, Mark; Heilmann, Ralf K.; Heine, Sarah N. T.; Hellickson, Tim; Frost, Jason; Marshall, Herman L.; Schulz, Norbert S.; Theriault-Shay, Adam

2017-08-01

X-ray polarimetry offers a new window into the high-energy universe, yet there has been no instrument so far that could measure the polarization of soft X-rays (about 17-80 Å) from astrophysical sources. The Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX Polarimeter) is a proposed sounding rocket experiment that uses a focusing optic and splits the beam into three channels. Each channel has a set of criticalangle transmission (CAT) gratings that disperse the x-rays onto a laterally graded multilayer (LGML) mirror, which preferentially reflects photons with a specific polarization angle. The three channels are oriented at 120 deg to each other and thus measure the three Stokes parameters: I, Q, and U. The period of the LGML changes with position. The main design challenge is to arrange the gratings so that they disperse the spectrum in such a way that all rays are dispersed onto the position on the multi-layer mirror where they satisfy the local Bragg condition despite arriving on the mirror at different angles due to the converging beam from the focusing optics. We present a polarimeteric Monte-Carlo ray-trace of this design to assess non-ideal effects from e.g. mirror scattering or the finite size of the grating facets. With mirror properties both simulated and measured in the lab for LGML mirrors of 80-200 layers we show that the reflectivity and the width of the Bragg-peak are sufficient to make this design work when non-ideal effects are included in the simulation. Our simulations give us an effective area curve, the modulation factor and the figure of merit for the REDSoX polarimeter. As an example, we simulate an observation of Mk 421 and show that we could easily detect a 20% linear polarization.

Soft x-ray spectroscopy studies of novel electronic materials using synchrotron radiation

NASA Astrophysics Data System (ADS)

Newby, David, Jr.

Soft x-ray spectroscopy can provide a wealth of information on the electronic structure of solids. In this work, a suite of soft x-ray spectroscopies is applied to organic and inorganic materials with potential applications in electronic and energy generation devices. Using the techniques of x-ray absorption (XAS), x-ray emission spectroscopy (XES), and x-ray photoemission spectroscopy (XPS), the fundamental properties of these different materials are explored. Cycloparaphenylenes (CPPs) are a recently synthesized family of cyclic hydrocarbons with very interesting properties and many potential applications. Unusual UV/Visible fluorescence trends have spurred a number of theoretical investigations into the electronic properties of the CPP family, but thus far no comprehensive electronic structure measurements have been conducted. XPS, XAS, and XES data for two varieties, [8]- and [10]-CPP, are presented here, and compared with the results of relevant DFT calculations. Turning towards more application-centered investigations, similar measurements are applied to two materials commonly used in solid oxide fuel cell (SOFC) cathodes: La1-xSrxMnO 3 (LSMO) and La1-xSr1- xCo1-yFe yO3 (LSCF). Both materials are structurally perovskites, but they exhibit strikingly different electronic properties. SOFC systems very efficiently produce electricity by catalyzing reactions between oxygen and petroleum-based hydrocarbons at high temperatures (> 800 C). Such systems are already utilized to great effect in many industries, but more widespread adoption could be had if the cells could operate at lower temperatures. Understanding the electronic structure and operational evolution of the cathode materials is essential for the development of better low-temperature fuel cells. LSCF is a mixed ion-electron conductor which holds promise for low-temperature SOFC applications. XPS spectra of LSCF thin films are collected as the films are heated and gas-dosed in a controlled environment. The

Energy-dispersive X-ray emission spectroscopy using an X-ray free-electron laser in a shot-by-shot mode

DOE PAGES

Alonso-Mori, Roberto; Kern, Jan; Gildea, Richard J.; ...

2012-11-05

The ultrabright femtosecond X-ray pulses provided by X-ray free-electron lasers open capabilities for studying the structure and dynamics of a wide variety of systems beyond what is possible with synchrotron sources. Recently, this “probe-before-destroy” approach has been demonstrated for atomic structure determination by serial X-ray diffraction of microcrystals. There has been the question whether a similar approach can be extended to probe the local electronic structure by X-ray spectroscopy. To address this, we have carried out femtosecond X-ray emission spectroscopy (XES) at the Linac Coherent Light Source using redox-active Mn complexes. XES probes the charge and spin states as wellmore » as the ligand environment, critical for understanding the functional role of redox-active metal sites. Kβ 1,3 XES spectra of Mn II and Mn 2 III,IV complexes at room temperature were collected using a wavelength dispersive spectrometer and femtosecond X-ray pulses with an individual dose of up to >100 MGy. The spectra were found in agreement with undamaged spectra collected at low dose using synchrotron radiation. Our results demonstrate that the intact electronic structure of redox active transition metal compounds in different oxidation states can be characterized with this shot-by-shot method. This opens the door for studying the chemical dynamics of metal catalytic sites by following reactions under functional conditions. Furthermore, the technique can be combined with X-ray diffraction to simultaneously obtain the geometric structure of the overall protein and the local chemistry of active metal sites and is expected to prove valuable for understanding the mechanism of important metalloproteins, such as photosystem II.« less

Energy-dispersive X-ray emission spectroscopy using an X-ray free-electron laser in a shot-by-shot mode

PubMed Central

Alonso-Mori, Roberto; Kern, Jan; Gildea, Richard J.; Sokaras, Dimosthenis; Weng, Tsu-Chien; Lassalle-Kaiser, Benedikt; Tran, Rosalie; Hattne, Johan; Laksmono, Hartawan; Hellmich, Julia; Glöckner, Carina; Echols, Nathaniel; Sierra, Raymond G.; Schafer, Donald W.; Sellberg, Jonas; Kenney, Christopher; Herbst, Ryan; Pines, Jack; Hart, Philip; Herrmann, Sven; Grosse-Kunstleve, Ralf W.; Latimer, Matthew J.; Fry, Alan R.; Messerschmidt, Marc M.; Miahnahri, Alan; Seibert, M. Marvin; Zwart, Petrus H.; White, William E.; Adams, Paul D.; Bogan, Michael J.; Boutet, Sébastien; Williams, Garth J.; Zouni, Athina; Messinger, Johannes; Glatzel, Pieter; Sauter, Nicholas K.; Yachandra, Vittal K.; Yano, Junko; Bergmann, Uwe

2012-01-01

The ultrabright femtosecond X-ray pulses provided by X-ray free-electron lasers open capabilities for studying the structure and dynamics of a wide variety of systems beyond what is possible with synchrotron sources. Recently, this “probe-before-destroy” approach has been demonstrated for atomic structure determination by serial X-ray diffraction of microcrystals. There has been the question whether a similar approach can be extended to probe the local electronic structure by X-ray spectroscopy. To address this, we have carried out femtosecond X-ray emission spectroscopy (XES) at the Linac Coherent Light Source using redox-active Mn complexes. XES probes the charge and spin states as well as the ligand environment, critical for understanding the functional role of redox-active metal sites. Kβ1,3 XES spectra of MnII and Mn2III,IV complexes at room temperature were collected using a wavelength dispersive spectrometer and femtosecond X-ray pulses with an individual dose of up to >100 MGy. The spectra were found in agreement with undamaged spectra collected at low dose using synchrotron radiation. Our results demonstrate that the intact electronic structure of redox active transition metal compounds in different oxidation states can be characterized with this shot-by-shot method. This opens the door for studying the chemical dynamics of metal catalytic sites by following reactions under functional conditions. The technique can be combined with X-ray diffraction to simultaneously obtain the geometric structure of the overall protein and the local chemistry of active metal sites and is expected to prove valuable for understanding the mechanism of important metalloproteins, such as photosystem II. PMID:23129631

X-Ray Instrument for Mars 2020 Rover is PIXL

NASA Image and Video Library

2014-07-31

This diagram depicts the sensor head of the Planetary Instrument for X-RAY Lithochemistry, or PIXL, which has been selected as one of seven investigations for the payload of NASA Mars 2020 rover mission.

Electron cyclotron resonance ion source plasma characterization by X-ray spectroscopy and X-ray imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mascali, David, E-mail: davidmascali@lns.infn.it; Castro, Giuseppe; Celona, Luigi

2016-02-15

An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs—Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed “on-line” during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and themore » beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure.« less

X-Ray Calorimeter Arrays for Astrophysics

NASA Technical Reports Server (NTRS)

Kilbourne, Caroline A.

2009-01-01

High-resolution x-ray spectroscopy is a powerful tool for studying the evolving universe. The grating spectrometers on the XMM and Chandra satellites started a new era in x-ray astronomy, but there remains a need for instrumentation that can provide higher spectral resolution with high throughput in the Fe-K band (around 6 keV) and can enable imaging spectroscopy of extended sources, such as supernova remnants and galaxy clusters. The instrumentation needed is a broad-band imaging spectrometer - basically an x-ray camera that can distinguish tens of thousands of x-ray colors. The potential benefits to astrophysics of using a low-temperature calorimeter to determine the energy of an incident x-ray photon via measurement of a small change in temperature was first articulated by S. H. Moseley over two decades ago. In the time since, technological progress has been steady, though full realization in an orbiting x-ray telescope is still awaited. A low-temperature calorimeter can be characterized by the type of thermometer it uses, and three types presently dominate the field. The first two types are temperature-sensitive resistors - semiconductors in the metal-insulator transition and superconductors operated in the superconducting-normal transition. The third type uses a paramagnetic thermometer. These types can be considered the three generations of x-ray calorimeters; by now each has demonstrated a resolving power of 2000 at 6 keV, but only a semiconductor calorimeter system has been developed to spaceflight readiness. The Soft X-ray Spectrometer on Astro-H, expected to launch in 2013, will use an array of silicon thermistors with I-IgTe x-ray absorbers that will operate at 50 mK. Both the semiconductor and superconductor calorimeters have been implemented in small arrays, kilo-pixel arrays of the superconducting calorimeters are just now being produced, and it is anticipated that much larger arrays will require the non-dissipative advantage of magnetic thermometers.

Probing molecular orientations in thin films by x-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Li, Y.; Li, P.; Lu, Z.-H.

2018-03-01

A great number of functional organic molecules in active thin-film layers of optoelectronic devices have highly asymmetric structures, such as plate-like, rod-like, etc. This makes molecular orientation an important aspect in thin-films as it can significantly affect both the optical and electrical performance of optoelectronic devices. With a combination of in-situ ultra violet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS) investigations for organic molecules having a broad range of structural properties, we discovered a rigid connection of core levels and frontier highest occupied molecular orbital levels at organic interfaces. This finding opens up opportunities of using X-ray photoemission spectroscopy as an alternative tool to UPS for providing an easy and unambiguous data interpretation in probing molecular orientations.

Hard X-ray and gamma-ray imaging spectroscopy for the next solar maximum

NASA Technical Reports Server (NTRS)

Hudson, H. S.; Crannell, C. J.; Dennis, B. R.; Spicer, D. S.; Davis, J. M.; Hurford, G. J.; Lin, R. P.

1990-01-01

The objectives and principles are described of a single spectroscopic imaging package that can provide effective imaging in the hard X- and gamma-ray ranges. Called the High-Energy Solar Physics (HESP) mission instrument for solar investigation, the device is based on rotating modulation collimators with germanium semiconductor spectrometers. The instrument is planned to incorporate thick modulation plates, and the range of coverage is discussed. The optics permit the coverage of high-contrast hard X-ray images from small- and medium-sized flares with large signal-to-noise ratios. The detectors allow angular resolution of less than 1 arcsec, time resolution of less than 1 arcsec, and spectral resolution of about 1 keV. The HESP package is considered an effective and important instrument for investigating the high-energy solar events of the near-term future efficiently.

Note: application of a pixel-array area detector to simultaneous single crystal X-ray diffraction and X-ray absorption spectroscopy measurements.

PubMed

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

2014-04-01

X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr0.67Sr0.33MnO3 film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam.

X-ray Photoelectron Spectroscopy Database (Version 4.1)

National Institute of Standards and Technology Data Gateway

SRD 20 X-ray Photoelectron Spectroscopy Database (Version 4.1) (Web, free access)   The NIST XPS Database gives access to energies of many photoelectron and Auger-electron spectral lines. The database contains over 22,000 line positions, chemical shifts, doublet splittings, and energy separations of photoelectron and Auger-electron lines.

Chemical speciation using high energy resolution PIXE spectroscopy in the tender X-ray range

NASA Astrophysics Data System (ADS)

Kavčič, Matjaž; Petric, Marko; Vogel-Mikuš, Katarina

2018-02-01

High energy resolution X-ray emission spectroscopy employing wavelength dispersive (WDS) crystal spectrometers can provide energy resolution on the level of core-hole lifetime broadening of the characteristic emission lines. While crystal spectrometers have been traditionally used in combination with electron excitation for major and minor element analysis, they have been rarely considered in proton induced X-ray emission (PIXE) trace element analysis mainly due to low detection efficiency. Compared to the simplest flat crystal WDS spectrometer the efficiency can be improved by employing cylindrically or even spherically curved crystals in combination with position sensitive X-ray detectors. When such spectrometer is coupled to MeV proton excitation, chemical bonding effects are revealed in the high energy resolution spectra yielding opportunity to extend the analytical capabilities of PIXE technique also towards chemical state analysis. In this contribution we will focus on the high energy resolution PIXE (HR-PIXE) spectroscopy in the tender X-ray range performed in our laboratory with our home-built tender X-ray emission spectrometer. Some general properties of high energy resolution PIXE spectroscopy in the tender X-ray range are presented followed by an example of sulfur speciation in biological tissue illustrating the capabilities as well as limitations of HR-PIXE method used for chemical speciation in the tender X-ray range.

High-resolution X-ray emission spectroscopy with transition-edge sensors: present performance and future potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uhlig, J.; Doriese, W. B.; Fowler, J. W.

2015-04-21

X-ray emission spectroscopy (XES) is a powerful element-selective tool to analyze the oxidation states of atoms in complex compounds, determine their electronic configuration, and identify unknown compounds in challenging environments. Until now the low efficiency of wavelength-dispersive X-ray spectrometer technology has limited the use of XES, especially in combination with weaker laboratory X-ray sources. More efficient energy-dispersive detectors have either insufficient energy resolution because of the statistical limits described by Fano or too low counting rates to be of practical use. This paper updates an approach to high-resolution X-ray emission spectroscopy that uses a microcalorimeter detector array of superconducting transition-edgemore » sensors (TESs). TES arrays are discussed and compared with conventional methods, and shown under which circumstances they are superior. It is also shown that a TES array can be integrated into a table-top time-resolved X-ray source and a soft X-ray synchrotron beamline to perform emission spectroscopy with good chemical sensitivity over a very wide range of energies.« less

Development of picosecond time-resolved X-ray absorption spectroscopy by high-repetition-rate laser pump/X-ray probe at Beijing Synchrotron Radiation Facility.

PubMed

Wang, Hao; Yu, Can; Wei, Xu; Gao, Zhenhua; Xu, Guang Lei; Sun, Da Rui; Li, Zhenjie; Zhou, Yangfan; Li, Qiu Ju; Zhang, Bing Bing; Xu, Jin Qiang; Wang, Lin; Zhang, Yan; Tan, Ying Lei; Tao, Ye

2017-05-01

A new setup and commissioning of transient X-ray absorption spectroscopy are described, based on the high-repetition-rate laser pump/X-ray probe method, at the 1W2B wiggler beamline at the Beijing Synchrotron Radiation Facility. A high-repetition-rate and high-power laser is incorporated into the setup with in-house-built avalanche photodiodes as detectors. A simple acquisition scheme was applied to obtain laser-on and laser-off signals simultaneously. The capability of picosecond transient X-ray absorption spectroscopy measurement was demonstrated for a photo-induced spin-crossover iron complex in 6 mM solution with 155 kHz repetition rate.

[Development of Nanotechnology for X-Ray Astronomy Instrumentation

NASA Technical Reports Server (NTRS)

Schattenburg, Mark L.

2004-01-01

This Research Grant provides support for development of nanotechnology for x-ray astronomy instrumentation. MIT has made significant progress in several development areas. In the last year we have made considerable progress in demonstrating the high-fidelity patterning and replication of x-ray reflection gratings. We developed a process for fabricating blazed gratings in silicon with extremely smooth and sharp sawtooth profiles, and developed a nanoimprint process for replication. We also developed sophisticated new fixturing for holding thin optics during metrology without causing distortion. We developed a new image processing algorithm for our Shack-Hartmann tool that uses Zernike polynomials. This has resulted in much more accurate and repeatable measurements on thin optics.

X-ray magnetic circular dichroism and hard X-ray photoelectron spectroscopy of tetragonal Mn72Ge28 epitaxial thin film

NASA Astrophysics Data System (ADS)

Kim, Jinhyeok; Mizuguchi, Masaki; Inami, Nobuhito; Ueno, Tetsuro; Ueda, Shigenori; Takanashi, Koki

2018-04-01

An epitaxially grown Mn72Ge28 film with a tetragonal crystal structure was fabricated. It was clarified that the film had a perpendicular magnetization and a high perpendicular magnetic anisotropy energy of 14.3 Merg/cm3. The electronic structure was investigated by X-ray magnetic circular dichroism and hard X-ray photoelectron spectroscopy. The obtained X-ray magnetic circular dichroism spectrum revealed that the Mn orbital magnetic moment governed the magnetocrystalline anisotropy of the Mn72Ge28 film. A doublet structure was observed for the Mn 2p3/2 peak of hard X-ray photoelectron spectrum, indicating the spin exchange interaction between the 2p core-hole and 3d valence electrons.

Doing Solar Science With Extreme-ultraviolet and X-ray High Resolution Imaging Spectroscopy

NASA Astrophysics Data System (ADS)

Doschek, G. A.

2005-12-01

In this talk I will demonstrate how high resolution extreme-ultraviolet (EUV) and/or X-ray imaging spectroscopy can be used to provide unique information for solving several current key problems of the solar atmosphere, e.g., the morphology and reconnection site of solar flares, the structure of the transition region, and coronal heating. I will describe the spectra that already exist relevant to these problems and what the shortcomings of the data are, and how an instrument such as the Extreme-ultraviolet Imaging Spectrometer (EIS) on Solar-B as well as other proposed spectroscopy missions such as NEXUS and RAM will improve on the existing observations. I will discuss a few particularly interesting properties of the spectra and atomic data for highly ionized atoms that are important for the science problems.

X-ray Fluorescence Spectroscopy: the Potential of Astrophysics-developed Techniques

NASA Astrophysics Data System (ADS)

Elvis, M.; Allen, B.; Hong, J.; Grindlay, J.; Kraft, R.; Binzel, R. P.; Masterton, R.

2012-12-01

X-ray fluorescence from the surface of airless bodies has been studied since the Apollo X-ray fluorescence experiment mapped parts of the lunar surface in 1971-1972. That experiment used a collimated proportional counter with a resolving power of ~1 and a beam size of ~1degree. Filters separated only Mg, Al and SI lines. We review progress in X-ray detectors and imaging for astrophysics and show how these advances enable much more powerful use of X-ray fluorescence for the study of airless bodies. Astrophysics X-ray instrumentation has developed enormously since 1972. Low noise, high quantum efficiency, X-ray CCDs have flown on ASCA, XMM-Newton, the Chandra X-ray Observatory, Swift and Suzaku, and are the workhorses of X-ray astronomy. They normally span 0.5 to ~8 keV with an energy resolution of ~100 eV. New developments in silicon based detectors, especially individual pixel addressable devices, such as CMOS detectors, can withstand many orders of magnitude more radiation than conventional CCDs before degradation. The capability of high read rates provides dynamic range and temporal resolution. Additionally, the rapid read rates minimize shot noise from thermal dark current and optical light. CMOS detectors can therefore run at warmer temperatures and with ultra-thin optical blocking filters. Thin OBFs mean near unity quantum efficiency below 1 keV, thus maximizing response at the C and O lines.such as CMOS detectors, promise advances. X-ray imaging has advanced similarly far. Two types of imager are now available: specular reflection and coded apertures. X-ray mirrors have been flown on the Einstein Observatory, XMM-Newton, Chandra and others. However, as X-ray reflection only occurs at small (~1degree) incidence angles, which then requires long focal lengths (meters), mirrors are not usually practical for planetary missions. Moreover the field of view of X-ray mirrors is comparable to the incident angle, so can only image relatively small regions. More useful

Probing interfacial characteristics of rubrene/pentacene and pentacene/rubrene bilayers with soft X-ray spectroscopy.

PubMed

Seo, J H; Pedersen, T M; Chang, G S; Moewes, A; Yoo, K-H; Cho, S J; Whang, C N

2007-08-16

The electronic structure of rubrene/pentacene and pentacene/rubrene bilayers has been investigated using soft X-ray absorption spectroscopy, resonant X-ray emission spectroscopy, and density-functional theory calculations. X-ray absorption and emission measurements reveal that it has been possible to alter the lowest unoccupied and the highest occupied molecular orbital states of rubrene in rubrene/pentacene bilayer. In the reverse case, one gets p* molecular orbital states originating from the pentacene layer. Resonant X-ray emission spectra suggest a reduction in the hole-transition probabilities for the pentacene/rubrene bilayer in comparison to reference pentacene layer. For the rubrenepentacene structure, the hole-transition probability shows an increase in comparison to the rubrene reference. We also determined the energy level alignment of the pentacene-rubrene interface by using X-ray and ultraviolet photoelectron spectroscopy. From these comparisons, it is found that the electronic structure of the pentacene-rubrene interface has a strong dependence on interface characteristics which depends on the order of the layers used.

The Astro-H High Resolution Soft X-Ray Spectrometer

NASA Technical Reports Server (NTRS)

Kelley, Richard L.; Akamatsu, Hiroki; Azzarell, Phillip; Bialas, Tom; Boyce, Kevin R.; Brown, Gregory V.; Canavan, Edgar; Chiao, Meng P.; Costantini, Elisa; DiPirro, Michael J.;

The Astro-H high resolution soft x-ray spectrometer

NASA Astrophysics Data System (ADS)

Kelley, Richard L.; Akamatsu, Hiroki; Azzarello, Phillipp; Bialas, Tom; Boyce, Kevin R.; Brown, Gregory V.; Canavan, Edgar; Chiao, Meng P.; Costantini, Elisa; DiPirro, Michael J.; Eckart, Megan E.; Ezoe, Yuichiro; Fujimoto, Ryuichi; Haas, Daniel; den Herder, Jan-Willem; Hoshino, Akio; Ishikawa, Kumi; Ishisaki, Yoshitaka; Iyomoto, Naoko; Kilbourne, Caroline A.; Kimball, Mark O.; Kitamoto, Shunji; Konami, Saori; Koyama, Shu; Leutenegger, Maurice A.; McCammon, Dan; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Moseley, Harvey; Murakami, Hiroshi; Murakami, Masahide; Noda, Hirofumi; Ogawa, Mina; Ohashi, Takaya; Okamoto, Atsushi; Ota, Naomi; Paltani, Stéphane; Porter, F. S.; Sakai, Kazuhiro; Sato, Kosuke; Sato, Yohichi; Sawada, Makoto; Seta, Hiromi; Shinozaki, Keisuke; Shirron, Peter J.; Sneiderman, Gary A.; Sugita, Hiroyuki; Szymkowiak, Andrew E.; Takei, Yoh; Tamagawa, Toru; Tashiro, Makoto; Terada, Yukikatsu; Tsujimoto, Masahiro; de Vries, Cor P.; Yamada, Shinya; Yamasaki, Noriko Y.; Yatsu, Yoichi

2016-07-01

We present the overall design and performance of the Astro-H (Hitomi) Soft X-Ray Spectrometer (SXS). The instrument uses a 36-pixel array of x-ray microcalorimeters at the focus of a grazing-incidence x-ray mirror Soft X-Ray Telescope (SXT) for high-resolution spectroscopy of celestial x-ray sources. The instrument was designed to achieve an energy resolution better than 7 eV over the 0.3-12 keV energy range and operate for more than 3 years in orbit. The actual energy resolution of the instrument is 4-5 eV as demonstrated during extensive ground testing prior to launch and in orbit. The measured mass flow rate of the liquid helium cryogen and initial fill level at launch predict a lifetime of more than 4 years assuming steady mechanical cooler performance. Cryogen-free operation was successfully demonstrated prior to launch. The successful operation of the SXS in orbit, including the first observations of the velocity structure of the Perseus cluster of galaxies, demonstrates the viability and power of this technology as a tool for astrophysics.

Nanosecond X-ray Photon Correlation Spectroscopy on Magnetic Skyrmions

DOE PAGES

Seaberg, M. H.; Holladay, B.; Lee, J. C. T.; ...

2017-08-09

We report an X-ray photon correlation spectroscopy method that exploits the recent development of the two-pulse mode at the Linac Coherent Light Source. By using coherent resonant X-ray magnetic scattering, we studied spontaneous fluctuations on nanosecond timescales in thin films of multilayered Fe/Gd that exhibit ordered stripe and skyrmion lattice phases. The correlation time of the fluctuations was found to differ between the skyrmion phase and near the stripe-skyrmion boundary. As a result, this technique will enable a significant new area of research on the study of equilibrium fluctuations in condensed matter.

Nanosecond X-ray Photon Correlation Spectroscopy on Magnetic Skyrmions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seaberg, M. H.; Holladay, B.; Lee, J. C. T.

We report an X-ray photon correlation spectroscopy method that exploits the recent development of the two-pulse mode at the Linac Coherent Light Source. By using coherent resonant X-ray magnetic scattering, we studied spontaneous fluctuations on nanosecond timescales in thin films of multilayered Fe/Gd that exhibit ordered stripe and skyrmion lattice phases. The correlation time of the fluctuations was found to differ between the skyrmion phase and near the stripe-skyrmion boundary. As a result, this technique will enable a significant new area of research on the study of equilibrium fluctuations in condensed matter.

X-Ray Spectroscopies of Warm Dense Matter

NASA Astrophysics Data System (ADS)

Hoidn, Oliver

This dissertation provides a perspective on the role of x-ray spectroscopy and diffraction diagnostics in experimental studies of warm dense matter (WDM). The primary focus of the work I discuss is the development of techniques to measure the structure and state variables of laboratory-generated WDM with a view towards both phenomenlogy and placing contraints on theoretical models. I present techniques adapted to two experimental venues for WDM studies: large-scale laser plasma facilities and x-ray free electron lasers. My focus is on the latter, in the context of which I have studied a dose enhancement technique that exploits nonlocal heat transport in nanostructured targets and considered several aspects of optimizing x-ray diffraction measurements. This work came into play in beam runs at the Linac Coherent Light Source (LCLS) in which my group performed x-ray diffraction studies of several materials heated to eV-scale temperatures. The results from these experiments include confirmation of the persistence of long-range crystalline order upon heating of metal oxides to tens of eV temperarures on the 40 fs timescale. One material, MgO, additionally manifested a surprising anomalous early onset in delocalization of valence charge density, contradicting predictions of all models based on either ground state electronic structure or (high-energy density) plasma physics. This particular result outlines a future path for studies of ordered insulators heated to temperatures on the order of the band gap. Such experiments will offer strong tests of electronic strucure theory, implementing a scientific approach that sees measurement of real-space charge density via x-ray diffraction (XRD) as a particularly effectve means to constrain density functional theory (DFT)-based modeling of the solid state/plasma transitional regime.

Pushing x-ray photon correlation spectroscopy beyond the continuous frame rate limit

DOE PAGES

Dufresne, Eric M.; Narayanan, Suresh; Sandy, Alec R.; ...

2016-01-06

We demonstrate delayed-frame X-ray Photon Correlation Spectroscopy with 120 microsecond time resolution, limited only by sample scattering rates, with a prototype Pixel-array detector capable of taking two image frames separated by 153 ns or less. Although the overall frame rate is currently limited to about 4 frame pairs per second, we easily measured millisecond correlation functions. In conclusion, this technology, coupled to the use of brighter synchrotrons such as Petra III or the NSLS-II should enable X-ray Photon Correlation Spectroscopy on microsecond time scales on a wider variety of materials.

The X-ray Pump-Probe instrument at the Linac Coherent Light Source.

PubMed

Chollet, Matthieu; Alonso-Mori, Roberto; Cammarata, Marco; Damiani, Daniel; Defever, Jim; Delor, James T; Feng, Yiping; Glownia, James M; Langton, J Brian; Nelson, Silke; Ramsey, Kelley; Robert, Aymeric; Sikorski, Marcin; Song, Sanghoon; Stefanescu, Daniel; Srinivasan, Venkat; Zhu, Diling; Lemke, Henrik T; Fritz, David M

2015-05-01

The X-ray Pump-Probe instrument achieves femtosecond time-resolution with hard X-ray methods using a free-electron laser source. It covers a photon energy range of 4-24 keV. A femtosecond optical laser system is available across a broad spectrum of wavelengths for generating transient states of matter. The instrument is designed to emphasize versatility and the scientific goals encompass ultrafast physical, chemical and biological processes involved in the transformation of matter and transfer of energy at the atomic scale.

High-order multilayer coated blazed gratings for high resolution soft x-ray spectroscopy

DOE PAGES

Voronov, Dmitriy L.; Goray, Leonid I.; Warwick, Tony; ...

2015-02-17

A grand challenge in soft x-ray spectroscopy is to drive the resolving power of monochromators and spectrometers from the 10 4 achieved routinely today to well above 10 5. This need is driven mainly by the requirements of a new technique that is set to have enormous impact in condensed matter physics, Resonant Inelastic X-ray Scattering (RIXS). Unlike x-ray absorption spectroscopy, RIXS is not limited by an energy resolution dictated by the core-hole lifetime in the excitation process. Using much higher resolving power than used for normal x-ray absorption spectroscopy enables access to the energy scale of soft excitations inmore » matter. These excitations such as magnons and phonons drive the collective phenomena seen in correlated electronic materials such as high temperature superconductors. RIXS opens a new path to study these excitations at a level of detail not formerly possible. However, as the process involves resonant excitation at an energy of around 1 keV, and the energy scale of the excitations one would like to see are at the meV level, to fully utilize the technique requires the development of monochromators and spectrometers with one to two orders of magnitude higher energy resolution than has been conventionally possible. Here we investigate the detailed diffraction characteristics of multilayer blazed gratings. These elements offer potentially revolutionary performance as the dispersive element in ultra-high resolution x-ray spectroscopy. In doing so, we have established a roadmap for the complete optimization of the grating design. Traditionally 1st order gratings are used in the soft x-ray region, but we show that as in the optical domain, one can work in very high spectral orders and thus dramatically improve resolution without significant loss in efficiency.« less

Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

NASA Technical Reports Server (NTRS)

Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

2010-01-01

An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

X-Ray Diffraction and Fluorescence Measurements for In Situ Planetary Instruments

NASA Astrophysics Data System (ADS)

Hansford, G.; Hill, K. S.; Talboys, D.; Vernon, D.; Ambrosi, R.; Bridges, J.; Hutchinson, I.; Marinangeli, L.

2011-12-01

The ESA/NASA ExoMars mission, due for launch in 2018, has a combined X-ray fluorescence/diffraction instrument, Mars-XRD, as part of the onboard analytical laboratory. The results of some XRF (X-ray fluorescence) and XRD (X-ray diffraction) tests using a laboratory chamber with representative performance are reported. A range of standard geological reference materials and analogues were used in these tests. The XRD instruments are core components of the forthcoming NASA Mars Science Laboratory (MSL) and ESA/NASA ExoMars missions and will provide the first demonstrations of the capabilities of combined XRD/XRF instrumentation in situ on an extraterrestrial planetary surface. The University of Leicester team is part of the Italy-UK collaboration that is responsible for building the ExoMars X-ray diffraction instrument, Mars-XRD [1,2]. Mars-XRD incorporates an Fe-55 radioisotope source and three fixed-position charge-coupled devices (CCDs) to simultaneously acquire an X-ray fluorescence spectrum and a diffraction pattern providing a measurement of both elemental and mineralogical composition. The CCDs cover an angular range of 2θ = 6° to 73° enabling the analysis of a wide range of geologically important minerals including phyllosilicates, feldspars, oxides, carbonates and evaporites. The identification of hydrous minerals may help identify past Martian hydrothermal systems capable of preserving traces of life. Here we present some initial findings from XRF and XRD tests carried out at the University of Leicester using an Fe-55 source and X-ray sensitive CCD. The XRF/XRD test system consists of a single CCD on a motorised arm, an Fe-55 X-ray source, a collimator and a sample table which approximately replicate the reflection geometry of the Mars-XRD instrument. It was used to test geological reference standard materials and Martian analogues. This work was funded by the Science and Technology Facilities Council, UK. References [1] Marinangeli, L., Hutchinson, I

Calcium in the Oxygen-Evolving Complex: Structural and Mechanistic Role Determined by X-ray Spectroscopy

PubMed Central

Yachandra, Vittal K.; Yano, Junko

2011-01-01

This review describes the results from X-ray absorption spectroscopy studies that have contributed to an understanding of the role of Ca in the photosynthetic water oxidation reaction. The results include the first Mn, Ca and Sr X-ray spectroscopy studies using Ca or Sr-substituted PS II samples that established the presence of a MnCa heteronuclear structure and its orientation, and the most recent Sr X-ray spectroscopy study using biosynthetically prepared Sr-containing PS II in the various S-states that provide important insights into the requirement for Ca in the mechanism of the Mn4Ca catalytic center. PMID:21524917

Stochastic stimulated electronic x-ray Raman spectroscopy

PubMed Central

Kimberg, Victor; Rohringer, Nina

2016-01-01

Resonant inelastic x-ray scattering (RIXS) is a well-established tool for studying electronic, nuclear, and collective dynamics of excited atoms, molecules, and solids. An extension of this powerful method to a time-resolved probe technique at x-ray free electron lasers (XFELs) to ultimately unravel ultrafast chemical and structural changes on a femtosecond time scale is often challenging, due to the small signal rate in conventional implementations at XFELs that rely on the usage of a monochromator setup to select a small frequency band of the broadband, spectrally incoherent XFEL radiation. Here, we suggest an alternative approach, based on stochastic spectroscopy, which uses the full bandwidth of the incoming XFEL pulses. Our proposed method is relying on stimulated resonant inelastic x-ray scattering, where in addition to a pump pulse that resonantly excites the system a probe pulse on a specific electronic inelastic transition is provided, which serves as a seed in the stimulated scattering process. The limited spectral coherence of the XFEL radiation defines the energy resolution in this process and stimulated RIXS spectra of high resolution can be obtained by covariance analysis of the transmitted spectra. We present a detailed feasibility study and predict signal strengths for realistic XFEL parameters for the CO molecule resonantly pumped at the O1s→π* transition. Our theoretical model describes the evolution of the spectral and temporal characteristics of the transmitted x-ray radiation, by solving the equation of motion for the electronic and vibrational degrees of freedom of the system self consistently with the propagation by Maxwell equations. PMID:26958585

The Athena X-ray Integral Field Unit (X-IFU)

NASA Technical Reports Server (NTRS)

Barret, Didier; Trong, Thein Lam; Den Herder, Jan-Willem; Piro, Luigi; Barcons, Xavier; Huovelin, Juhani; Kelley, Richard; Mas-Hesse, J. Miquel; Mitsuda, Kazuhisa; Paltani, Stephane;

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

PubMed Central

Yachandra, Vittal K

2002-01-01

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. PMID:12437873

Excited state X-ray absorption spectroscopy: Probing both electronic and structural dynamics

NASA Astrophysics Data System (ADS)

Neville, Simon P.; Averbukh, Vitali; Ruberti, Marco; Yun, Renjie; Patchkovskii, Serguei; Chergui, Majed; Stolow, Albert; Schuurman, Michael S.

2016-10-01

We investigate the sensitivity of X-ray absorption spectra, simulated using a general method, to properties of molecular excited states. Recently, Averbukh and co-workers [M. Ruberti et al., J. Chem. Phys. 140, 184107 (2014)] introduced an efficient and accurate L 2 method for the calculation of excited state valence photoionization cross-sections based on the application of Stieltjes imaging to the Lanczos pseudo-spectrum of the algebraic diagrammatic construction (ADC) representation of the electronic Hamiltonian. In this paper, we report an extension of this method to the calculation of excited state core photoionization cross-sections. We demonstrate that, at the ADC(2)x level of theory, ground state X-ray absorption spectra may be accurately reproduced, validating the method. Significantly, the calculated X-ray absorption spectra of the excited states are found to be sensitive to both geometric distortions (structural dynamics) and the electronic character (electronic dynamics) of the initial state, suggesting that core excitation spectroscopies will be useful probes of excited state non-adiabatic dynamics. We anticipate that the method presented here can be combined with ab initio molecular dynamics calculations to simulate the time-resolved X-ray spectroscopy of excited state molecular wavepacket dynamics.

Rolf Mewe: a career devoted to X-ray spectroscopy

NASA Astrophysics Data System (ADS)

Kaastra, Jelle S.; Mewe, Rolf

2005-06-01

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.

Photochemically Generated Thiyl Free Radicals Observed by X-ray Absorption Spectroscopy

DOE PAGES

Sneeden, Eileen Y.; Hackett, Mark J.; Cotelesage, Julien J. H.; ...

2017-07-27

Sulfur-based thiyl radicals are known to be involved in a wide range of chemical and biological processes, but they are often highly reactive, which makes them difficult to observe directly. We report herein X-ray absorption spectra and analysis that support the direct observation of two different thiyl species generated photochemically by X-ray irradiation. The thiyl radical sulfur K-edge X-ray absorption spectra of both species are characterized by a uniquely low energy transition at about 2465 eV, which occurs at a lower energy than any previously observed feature at the sulfur K-edge and corresponds to a 1s → 3p transition tomore » the singly occupied molecular orbital of the free radical. In conclusion, our results constitute the first observation of substantial levels of thiyl radicals generated by X-ray irradiation and detected by sulfur K-edge X-ray absorption spectroscopy.« less

Science Instruments for the Advanced X-Ray Astrophysics Facility (AXAF)

NASA Technical Reports Server (NTRS)

Winkler, Carl E.; Cumings, Nesbitt P.; Randolph, Joseph L.; Talley, Drayton H.

1993-01-01

The AXAF program has undergone major changes since the Announcement of Opportunity was extended by NASA Headquarters in 1983. The Science Instruments (SI's) for AXAF have also experienced several design changes since they were competitively selected in 1985. Moreover, two separate complementary missions are now being baselined for AXAF; one is designated AXAF-I for imaging and will include the high precision Wolter type I optics, and the other is called AXAF-S for spectroscopy. The resulting less-costly AXAF will still be superior to any previous x-ray observatories. Both missions continue to be managed. AXAF-I contains two focal plane SI's, the High Resolution Camera (HRC), and the AXAF Charge-Coupled Device (CCD) imaging spectrometer (ACIS), as well as the High-Energy Transmission Grating Spectrometer (HETGS) and the Low-Energy Transmission Grating Spectrometer (LETGS). Optics/Cryogenics Division (BECD). AXAF-S features only one focal plane SI, the X-Ray Spectrometer (XRS). The grazing incidence mirrors for this mission are mainly to provide a large collecting area and to concentrate these x-ray photons onto the XRS detector. Precise focusing, although preferred, is of secondary importance. Nested conical foil mirrors are currently baselined; however, replicated imaging optics are being evaluated for collecting efficiency and cost. AXAF-S is scheduled to be launched in late 1999. It has been designated as an MSFC in-house project. In addition to overall management, MSFC is fully responsible for the design, development, integration, and test of the complete AXAF-S observatory, including the XRS which will be furnished by the Goddard Space Flight Center (GSFC). Together, AXAF-I and AXAF-S constitute the third of NASA's series of Great Observatories, joining the Hubble space telescope (HST) and the Gamma-Ray Observatory (GRO) which are already operational. The develop- ment, launch, and operation of the Space InfraRed Telescope Facility (SIRTF) will follow later to

Synchrotron-based ambient pressure X-ray photoelectron spectroscopy of hydrogen and helium

NASA Astrophysics Data System (ADS)

Zhong, Jian-Qiang; Wang, Mengen; Hoffmann, William H.; van Spronsen, Matthijs A.; Lu, Deyu; Boscoboinik, J. Anibal

2018-02-01

Contrary to popular belief, it is possible to obtain X-ray photoelectron spectra for elements lighter than lithium, namely hydrogen and helium. The literature is plagued with claims of this impossibility, which holds true for lab-based X-ray sources. However, this limitation is merely technical and is related mostly to the low X-ray photoionization cross-sections of the 1s orbitals of hydrogen and helium. In this letter, we show that, using ambient pressure X-ray photoelectron spectroscopy (XPS), a bright-enough X-ray source allows the study of these elusive elements. This has important implications in the understanding of the limitations of one of the most useful techniques in materials science, and moreover, it potentially opens the possibility of using XPS to directly study the most abundant element in the universe.

Calorimetric Low-Temperature Detectors for X-Ray Spectroscopy on Trapped Highly-Charged Heavy Ions

NASA Technical Reports Server (NTRS)

Kilbourne, Caroline; Kraft-Bermuth, S.; Andrianov, V.; Bleile, A.; Echler, A.; Egelhof, P.; Ilieva, S.; Kilbourne, C.; McCammon, D.

2012-01-01

The application of Calorimetric Low-Temperature Detectors (CLTDs) has been proposed at the Heavy-Ion TRAP facility HITRAP which is currently being installed at the Helmholtz Research Center for Heavy Ion Research GSI. This cold ion trap setup will allow the investigation of X-rays from ions practically at rest, for which the excellent energy resolution of CLTDs can be used to its full advantage. However, the relatively low intensities at HITRAP demand larger solid angles and an optimized cryogenic setup. The influence of external magnetic fields has to be taken into account. CLTDs will also be a substantial part of the instrumental equipment at the future Facility for Antiproton and Heavy Ion Research (FAIR), for which a wide variety of high-precision X-ray spectroscopy experiments has been proposed. This contribution will give an overview on the chances and challenges for the application of CLTDs at HITRAP as well as perspectives for future experiments at the FAIR facility.

An alignment method for mammographic X-ray spectroscopy under clinical conditions.

PubMed

Miyajima, S; Imagawa, K; Matsumoto, M

2002-09-01

This paper describes an alignment method for mammographic X-ray spectroscopy under clinical conditions. A pinhole, a fluorescent screen, a laser device and the case for a detector are used for alignment of the focal spot, a collimator and a detector. The method determines the line between the focal spot and the point of interest in an X-ray field radiographically. The method allows alignment for both central axis and off-axis directions.

In situ study of an oxidation reaction on a Pt/C electrode by ambient pressure hard X-ray photoelectron spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takagi, Yasumasa, E-mail: ytakagi@ims.ac.jp; Uemura, Yohei; Yokoyama, Toshihiko

2014-09-29

We have constructed an ambient pressure X-ray photoelectron spectroscopy instrument that uses hard X-ray radiation at the high-performance undulator beamline BL36XU of SPring-8. The dependence of the Au 4f peak intensity from Au foil on the ambient N{sub 2} pressure was measured. At a photon energy of 7.94 keV, the Au 4f peak intensity maintained 40% at 3000 Pa compared with that at high vacuum. We designed a polymer electrolyte fuel cell that allows us to perform X-ray photoelectron spectroscopy measurements of an electrode under working conditions. The oxidized Pt peaks were observed in the Pt 3d{sub 5/2} level of Pt nanoparticlesmore » in the cathode, and the peaks clearly depended on the applied voltage between the anode and cathode. Our apparatus can be applied as a valuable in situ tool for the investigation of the electronic states and adsorbed species of polymer electrolyte fuel cell electrode catalysts under the reaction conditions.« less

Pushing the Boundaries of Suborbital Soft X-ray Spectroscopy

NASA Astrophysics Data System (ADS)

McEntaffer, Randall

optics are planned for every future large X-ray mission and flight-proving the design is extremely important. The gratings will be radially grooved and blazed to reduce grating aberrations and to focus the spectrum to one side of zero-order. Gratings of this type have been well developed by the IXO Off- Plane X-ray Grating Spectrometer concept study, but have not been flight proven. The spectrum will be focused onto high spatial resolution CCD detectors. OGRE will draw heavily from the heritage gained from OGRESS. OGRE will observe Capella. Due to its high flux and spectral line density, Capella is an ideal target for showcasing the resolution capabilities of our instrument. As an important calibration target, our improved resolution measurements will be extremely helpful for many future X-ray observations. OGRESS has already provided three thesis projects for past graduate students. The upgrades and flights proposed here will produce at least two more PhD theses. This program in hands-on training of young scientists in the techniques of instrumental X-ray astronomy has proven very successful over nearly three decades, leading to high rates of launch, publication, graduation, and flight qualification of instrumental PI's. It will also provide full experiment cycle experience - design, fabrication, tolerancing, assembly, flight-qualification, calibration, integration, launch, and data analysis - with reflection gratings, GEM and CCD detectors, and other technologies suitable for adaptation to NASA's major missions. The University of Iowa and University of Colorado programs in suborbital X-ray astronomy represent an exciting mix of compelling science, cutting- edge technology development, and training of young scientists.

The UHURU X-ray instrument.

NASA Technical Reports Server (NTRS)

Jagoda, N.; Austin, G.; Mickiewicz, S.; Goddard, R.

1972-01-01

On Dec. 12, 1970, the UHURU X-ray observatory was launched into equatorial orbit with the prime mission of conducting an all-sky survey of astronomical X-ray sources with intensities of 0.00005 Sco-X1 or greater. The X-ray detection system contains 12 gas-filled proportional counters, 6 behind each collimator. The aspect system is discussed together with the structure, the pulse height analyzer, the command system, the calibration system, and the power distribution system. Pulse shape discrimination circuits used on UHURU use the same technique that was used on the system originally developed for large area proportional counters described by Gorenstein and Mickiewicz (1968).

Synchrotron-based ambient pressure X-ray photoelectron spectroscopy of hydrogen and helium

DOE PAGES

Zhong, Jian-Qiang; Wang, Mengen; Hoffmann, William H.; ...

2018-03-01

Contrary to popular belief, it is possible to obtain X-ray photoelectron spectra for elements lighter than lithium, namely hydrogen and helium. The literature is plagued with claims of this impossibility, which holds true for lab-based X-ray sources. However, this limitation is merely technical and is related mostly to the low X-ray photoionization cross-sections of the 1s orbitals of hydrogen and helium. Here, we show that, using ambient pressure X-ray photoelectron spectroscopy (XPS), a bright-enough X-ray source allows the study of these elusive elements. This has important implications in the understanding of the limitations of one of the most useful techniquesmore » in materials science, and moreover, it potentially opens the possibility of using XPS to directly study the most abundant element in the universe.« less

Synchrotron-based ambient pressure X-ray photoelectron spectroscopy of hydrogen and helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Jian-Qiang; Wang, Mengen; Hoffmann, William H.

Contrary to popular belief, it is possible to obtain X-ray photoelectron spectra for elements lighter than lithium, namely hydrogen and helium. The literature is plagued with claims of this impossibility, which holds true for lab-based X-ray sources. However, this limitation is merely technical and is related mostly to the low X-ray photoionization cross-sections of the 1s orbitals of hydrogen and helium. Here, we show that, using ambient pressure X-ray photoelectron spectroscopy (XPS), a bright-enough X-ray source allows the study of these elusive elements. This has important implications in the understanding of the limitations of one of the most useful techniquesmore » in materials science, and moreover, it potentially opens the possibility of using XPS to directly study the most abundant element in the universe.« less

The X-ray Pump–Probe instrument at the Linac Coherent Light Source

DOE PAGES

Chollet, Matthieu; Alonso-Mori, Roberto; Cammarata, Marco; ...

2015-04-21

The X-ray Pump–Probe instrument achieves femtosecond time-resolution with hard X-ray methods using a free-electron laser source. It covers a photon energy range of 4–24 keV. A femtosecond optical laser system is available across a broad spectrum of wavelengths for generating transient states of matter. The instrument is designed to emphasize versatility and the scientific goals encompass ultrafast physical, chemical and biological processes involved in the transformation of matter and transfer of energy at the atomic scale.

X-ray and optical spectroscopy of the massive young open cluster IC 1805

NASA Astrophysics Data System (ADS)

Rauw, G.; Nazé, Y.

2016-10-01

Context. Very young open clusters are ideal places to study the X-ray properties of a homogeneous population of early-type stars. In this respect, the IC 1805 open cluster is very interesting as it hosts the O4 If+ star HD 15570 thought to be in an evolutionary stage intermediate between a normal O-star and a Wolf-Rayet star. Aims: Such a star could provide a test for theoretical models aiming at explaining the empirical scaling relation between the X-ray and bolometric luminosities of O-type stars. Methods: We have observed IC 1805 with XMM-Newton and further collected optical spectroscopy of some of the O-star members of the cluster. Results: The optical spectra allow us to revisit the orbital solutions of BD+60° 497 and HD 15558, and provide the first evidence of binarity for BD+60° 498. X-ray emission from colliding winds does not appear to play an important role among the O-stars of IC 1805. Notably, the X-ray fluxes do not vary significantly between archival X-ray observations and our XMM-Newton pointing. The very fast rotator BD+60° 513, and to a lesser extent the O4 If+ star HD 15570 appear somewhat underluminous. Whilst the underluminosity of HD 15570 is only marginally significant, its amplitude is found to be compatible with theoretical expectations based on its stellar and wind properties. A number of other X-ray sources are detected in the field, and the brightest objects, many of which are likely low-mass pre-main sequence stars, are analyzed in detail. Based on observations collected with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA), and with the TIGRE telescope (La Luz, Mexico).Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/594/A82

Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butorin, S.M.; Guo, J.; Magnuson, M.

1997-04-01

Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of themore » exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state.« less

X-ray Spectroscopy and Magnetism in Mineralogy

NASA Astrophysics Data System (ADS)

Sainctavit, Philippe; Brice-Profeta, Sandrine; Gaudry, Emilie; Letard, Isabelle; Arrio, Marie-Anne

The objective of this paper is to present the kind of information that can be gained in the field of mineralogy from the use of x-ray magnetic spectroscopies. We review some of the questions that are unsettled and that could benefit from an interdisciplinary approach where magnetism, spectroscopy and mineralogy could be mixed. Most of the attention is focused on iron and some other 3d transition elements. The mineralogy of planetary cores and its relation with known meteorites are exemplified. The various oxide phases in the mantle and the nature of iron in these phases is also underlined. The presence of transition elements in insulating minerals and its relation with macroscopic properties such as the color of gemstones are reviewed. Finally an introduction to paleomagnetism is given with a special attention to nanomaghemites.

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

NASA Astrophysics Data System (ADS)

Guimarães, F. F.; Kimberg, V.; Felicíssimo, V. C.; Gel'Mukhanov, F.; Cesar, A.; Ågren, H.

2005-07-01

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.

Diamond sensors and polycapillary lenses for X-ray absorption spectroscopy.

PubMed

Ravel, B; Attenkofer, K; Bohon, J; Muller, E; Smedley, J

2013-10-01

Diamond sensors are evaluated as incident beam monitors for X-ray absorption spectroscopy experiments. These single crystal devices pose a challenge for an energy-scanning experiment using hard X-rays due to the effect of diffraction from the crystalline sensor at energies which meet the Bragg condition. This problem is eliminated by combination with polycapillary lenses. The convergence angle of the beam exiting the lens is large compared to rocking curve widths of the diamond. A ray exiting one capillary from the lens meets the Bragg condition for any reflection at a different energy from the rays exiting adjacent capillaries. This serves to broaden each diffraction peak over a wide energy range, allowing linear measurement of incident intensity over the range of the energy scan. Extended X-ray absorption fine structure data are measured with a combination of a polycapillary lens and a diamond incident beam monitor. These data are of comparable quality to data measured without a lens and with an ionization chamber monitoring the incident beam intensity.

Solid state structural investigations of the bis(chalcone) compound with single crystal X-ray crystallography, DFT, gamma-ray spectroscopy and chemical spectroscopy methods

NASA Astrophysics Data System (ADS)

Yakalı, Gül; Biçer, Abdullah; Eke, Canel; Cin, Günseli Turgut

2018-04-01

A bis(chalcone), (2E,6E)-2,6-bis((E)-3phenylallidene)cyclohexanone, was characterized by 1H NMR, 13C NMR, FTIR, UV-Vis spectroscopy, gamma-ray spectroscopy and single crystal X- ray structural analysis. The optimized molecular structure of the compound is calculated using DFT/B3LYP with 6-31G (d,p) level. The calculated geometrical parameters are in good agreement with the experimental data obtained from our reported X-ray structure. The powder and single crystal compounds were gama-irradiated using clinical electron linear accelerator and 60Co gamma-ray source, respectively. Spectral studies (1H NMR, 13C NMR, FTIR and UV-Vis) of powder chalcone compound were also investigated before and after irradiation. Depending on the irradiation notable changes were observed in spectral features powder sample. Single crystal X-ray diffraction investigation shows that both unirradiated and irradiated single crystal samples crystallizes in a orthorhombic crystal system in the centrosymmetric space group Pbcn and exhibits an C-H..O intramolecular and intermolecular hydrogen bonds. The crystal packing is stabilised by strong intermolecular bifurcate C-H..O hydrogen bonds and π…π stacking interactions. The asymmetric unit of the title compound contains one-half of a molecule. The other half of the molecule is generated with (1-x,y,-3/2-z) symmetry operator. The molecule is almost planar due to having π conjugated system of chalcones. However, irradiated single crystal compound showed significant changes lattice parameters, crystal volume and density. According to results of gamma-ray spectroscopy, radioactive elements of powder compound which are 123Sb(n,g),124Sb,57Fe(g,p),56Mn, 55Mn(g,n), and 54Mn were determined using photoactivation analysis. However, the most intensive gamma-ray energy signals are 124Sb.

Status of the Micro-X Sounding Rocket X-Ray Spectrometer

NASA Technical Reports Server (NTRS)

Goldfinger, D. C.; Adams, J. S.; Baker, R.; Bandler, S. R.; Danowski, M. E.; Doriese, W. B.; Eckart, M. E.; Figueroa-Feliciano, E.; Hilton, G. C.; Hubbard, A. J. F.;

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szlachetko, J.; Institute of Physics, Jan Kochanowski University, 25-406 Kielce; Nachtegaal, M.

2012-10-15

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.

Chemical Modification of Graphene Oxide by Nitrogenation: An X-ray Absorption and Emission Spectroscopy Study

DOE PAGES

Chuang, Cheng-Hao; Ray, Sekhar C.; Mazumder, Debarati; ...

2017-02-10

Nitrogen-doped graphene oxides (GO:N x) were synthesized by a partial reduction of graphene oxide (GO) using urea [CO(NH 2) 2 ]. Their electronic/bonding structures were investigated using X-ray absorption near-edge structure (XANES), valence-band photoemission spectroscopy (VB-PES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). During GO:N x synthesis, different nitrogen-bonding species, such as pyrrolic/graphitic-nitrogen, were formed by replacing of oxygen-containing functional groups. At lower N-content (2.7 at%), pyrrolic-N, owing to surface and subsurface diffusion of C, N and NH is deduced from various X-ray spectroscopies. In contrast, at higher N-content (5.0 at%) graphitic nitrogen was formed in whichmore » each N-atom trigonally bonds to three distinct sp 2 -hybridized carbons with substitution of the N-atoms for C atoms in the graphite layer. Upon nitrogen substitution, the total density of state close to Fermi level is increased to raise the valence-band maximum, as revealed by VB-PES spectra, indicating an electron donation from nitrogen, molecular bonding C/N/O coordination or/and lattice structure reorganization in GO:N x . The well-ordered chemical environments induced by nitrogen dopant are revealed by XANES and RIXS measurements.« less

Simulated 'On-Line' Wear Metal Analysis of Lubricating Oils by X-Ray Fluorescence Spectroscopy

NASA Technical Reports Server (NTRS)

Kelliher, Warren C.; Partos, Richard D.; Nelson, Irina

1996-01-01

The objective of this project was to assess the sensitivity of X-ray Fluorescence Spectroscopy (XFS) for quantitative evaluation of metal particle content in engine oil suspensions and the feasibility of real-time, dynamic wear metal analysis. The study was focused on iron as the majority wear metal component. Variable parameters were: particle size, particle concentration and oil velocity. A commercial XFS spectrometer equipped with interchangeable static/dynamic (flow cell) sample chambers was used. XFS spectra were recorded for solutions of Fe-organometallic standard and for a series of DTE oil suspensions of high purity spherical iron particles of 2g, 4g, and 8g diameter, at concentrations from 5 ppm to 5,000 ppm. Real contaminated oil samples from Langley Air Force Base aircraft engines and NASA Langley Research Center wind tunnels were also analyzed. The experimental data conform the reliability of XFS as the analytical method of choice for this project. Intrinsic inadequacies of the instrument for precise analytic work at low metal concentrations were identified as being related to the particular x-ray beam definition, system geometry, and flow-cell materials selection. This work supports a proposal for the design, construction and testing of a conceptually new, miniature XFS spectrometer with superior performance, dedicated to on-line, real-time monitoring of lubricating oils in operating engines. Innovative design solutions include focalization of the incident x-ray beam, non-metal sample chamber, and miniaturization of the overall assembly. The instrument would contribute to prevention of catastrophic engine failures. A proposal for two-year funding has been presented to NASA Langley Research Center Internal Operation Group (IOG) Management, to continue the effort begun by this summer's project.

The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

DOE PAGES

Liang, Mengning; Williams, Garth J.; Messerschmidt, Marc; ...

2015-04-15

The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100 nm focus and one a 1 µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter.

Development of a spectro-electrochemical cell for soft X-ray photon-in photon-out spectroscopy

NASA Astrophysics Data System (ADS)

Ishihara, Tomoko; Tokushima, Takashi; Horikawa, Yuka; Kato, Masaru; Yagi, Ichizo

2017-10-01

We developed a spectro-electrochemical cell for X-ray absorption and X-ray emission spectroscopy, which are element-specific methods to study local electronic structures in the soft X-ray region. In the usual electrochemical measurement setup, the electrode is placed in solution, and the surface/interface region of the electrode is not normally accessible by soft X-rays that have low penetration depth in liquids. To realize soft X-ray observation of electrochemical reactions, a 15-nm-thick Pt layer was deposited on a 150-nm-thick film window with an adhesive 3-nm-thick Ti layer for use as both the working electrode and the separator window between vacuum and a sample liquid under atmospheric pressure. The designed three-electrode electrochemical cell consists of a Pt film on a SiC window, a platinized Pt wire, and a commercial Ag|AgCl electrode as the working, counter, and reference electrodes, respectively. The functionality of the cell was tested by cyclic voltammetry and X-ray absorption and emission spectroscopy. As a demonstration, the electroplating of Pb on the Pt/SiC membrane window was measured by X-ray absorption and real-time monitoring of fluorescence intensity at the O 1s excitation.

Oxidant K edge x-ray emission spectroscopy of UF 4 and UO 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tobin, J. G.; Yu, S. -W.; Qiao, R.

The K-Edge (1s) x-ray emission spectroscopy of uranium tetrafluoride and uranium dioxide were compared to each other and to the results of a pair of earlier cluster calculations. Here, using a very simplified approach, it is possible to qualitatively reconstruct the main features of the x-ray emission spectra from the cluster calculation state energies and 2p percentages.

Oxidant K edge x-ray emission spectroscopy of UF 4 and UO 2

DOE PAGES

Tobin, J. G.; Yu, S. -W.; Qiao, R.; ...

2018-01-31

The K-Edge (1s) x-ray emission spectroscopy of uranium tetrafluoride and uranium dioxide were compared to each other and to the results of a pair of earlier cluster calculations. Here, using a very simplified approach, it is possible to qualitatively reconstruct the main features of the x-ray emission spectra from the cluster calculation state energies and 2p percentages.

X-ray Photoelectron Spectroscopy study of CaV1-xMoxO3-δ

NASA Astrophysics Data System (ADS)

Belyakov, S. A.; Kuznetsov, M. V.; Shkerin, S. N.

2018-06-01

An investigation was carried out on perovskite-based derivatives of CaV1-xMoxO3-δ using X-ray Photoelectron Spectroscopy (XPS). According to the XRD pattern, the area of homogeneity covers the region from x = 0 to x = 0.6. Wide XPS-peaks of Ca, V, Mo and O are observed, signalling that elements are presented in multiple states. A model for explaining the large chemical shifts of XPS peaks due to different charging effects on different parts of the sample surface is proposed.

What Can Be Learned from X-Ray Spectroscopy Concerning Hot Gas in the Local Bubble and Charge Exchange Processes?

NASA Technical Reports Server (NTRS)

Snowden, S. L.

2008-01-01

Both solar wind charge exchange emission and diffuse thermal emission from the Local Bubble are strongly dominated in the soft X-ray band by lines from highly ionized elements. While both processes share many of the same lines, the spectra should differ significantly due to the different production mechanisms, abundances, and ionization states. Despite their distinct spectral signatures, current and past observatories have lacked the spectral resolution to adequately distinguish between the two sources. High-resolution X-ray spectroscopy instrumentation proposed for future missions has the potential to answer fundamental questions such as whether there is any hot plasma in the Local Hot Bubble, and if so, what are the abundances of the emitting plasma and whether the plasma is in equilibrium. Such instrumentation will provide dynamic information about the solar wind including data on ion species which are currently difficult to track. It will also make possible remote sensing of the solar wind.

SphinX x-ray spectrophotometer

NASA Astrophysics Data System (ADS)

Kowaliński, Mirosław

2012-05-01

This paper presents assumptions to a PhD thesis. The thesis will be based on the construction of Solar Photometer in X-rays (SphinX). SphinX was an instrument developed to detect the soft X-rays from the Sun. It was flown on board the Russian CORONAS-Photon satellite from January 30, 2009 to the end of November, 2009. During 9 months in orbit SphinX provided an excellent and unique set of observations. It revealed about 750 flares and brightenings. The instrument observed in energy range 1.0 - 15.0 keV with resolution below ~0.5 keV. Here, the SphinX instrument objectives, design, performance and operation principle are described. Below results of mechanical and thermal - vacuum tests necessary to qualify the instrument to use in space environment are presented. Also the calibration results of the instrument are discussed. In particular detail it is described the Electrical Ground Support Equipment (EGSE) for SphinX. The EGSE was used for all tests of the instrument. At the end of the paper results obtained from the instrument during operation in orbit are discussed. These results are compared with the other similar measurements performed from the separate spacecraft instruments. It is suggested design changes in future versions of SphinX.

A high-temperature furnace for in situ synchrotron X-ray spectroscopy under controlled atmospheric conditions.

PubMed

Eeckhout, Sigrid Griet; Gorges, Bernard; Barthe, Laurent; Pelosi, Orietta; Safonova, Olga; Giuli, Gabriele

2008-09-01

A high-temperature furnace with an induction heater coil has been designed and constructed for in situ X-ray spectroscopic experiments under controlled atmospheric conditions and temperatures up to 3275 K. The multi-purpose chamber design allows working in backscattering and normal fluorescence mode for synchrotron X-ray absorption and emission spectroscopy. The use of the furnace is demonstrated in a study of the in situ formation of Cr oxide between 1823 K and 2023 K at logPO(2) values between -10.0 and -11.3 using X-ray absorption near-edge spectroscopy. The set-up is of particular interest for studying liquid metals, alloys and other electrically conductive materials under extreme conditions.

Low Dose X-Ray Speckle Visibility Spectroscopy Reveals Nanoscale Dynamics in Radiation Sensitive Ionic Liquids

NASA Astrophysics Data System (ADS)

Verwohlt, Jan; Reiser, Mario; Randolph, Lisa; Matic, Aleksandar; Medina, Luis Aguilera; Madsen, Anders; Sprung, Michael; Zozulya, Alexey; Gutt, Christian

2018-04-01

X-ray radiation damage provides a serious bottleneck for investigating microsecond to second dynamics on nanometer length scales employing x-ray photon correlation spectroscopy. This limitation hinders the investigation of real time dynamics in most soft matter and biological materials which can tolerate only x-ray doses of kGy and below. Here, we show that this bottleneck can be overcome by low dose x-ray speckle visibility spectroscopy. Employing x-ray doses of 22-438 kGy and analyzing the sparse speckle pattern of count rates as low as 6.7 ×10-3 per pixel, we follow the slow nanoscale dynamics of an ionic liquid (IL) at the glass transition. At the prepeak of nanoscale order in the IL, we observe complex dynamics upon approaching the glass transition temperature TG with a freezing in of the alpha relaxation and a multitude of millisecond local relaxations existing well below TG . We identify this fast relaxation as being responsible for the increasing development of nanoscale order observed in ILs at temperatures below TG .

Pushing the Boundaries of X-ray Grating Spectroscopy in a Suborbital Rocket

NASA Technical Reports Server (NTRS)

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

2013-01-01

Developments in grating spectroscopy are paramount for meeting the soft X-ray science goals of future NASA X-ray Observatories. While developments in the laboratory setting have verified the technical feasibility of using off-plane reflection gratings to reach this goal, flight heritage is a key step in the development process toward large missions. To this end we have developed a design for a suborbital rocket payload employing an Off-Plane X-ray Grating Spectrometer. This spectrometer utilizes slumped glass Wolter-1 optics, an array of gratings, and a CCD camera. We discuss the unique capabilities of this design, the expected performance, the science return, and the perceived impact to future missions.

X-ray Spectroscopy of a TDE

NASA Astrophysics Data System (ADS)

Kochanek, Christopher

2017-09-01

Tidal disruption events (TDE), where supermassive black holes destroy stars to produce accretion flares, are of great current observational and theoretical interest. Here we propose a four epoch HRC/LETG X-ray spectroscopic ``movie'' of a TDE spread over the first 40 days of an X-ray bright TDE, including any discovered by our ASAS-SN survey, supported and extended by higher cadence Swift XRT/UVOT observations over the first 100 days. For this next X-ray bright TDE, we will measure the evolution of the X-ray emission (luminosity/temperature) from the hot accretion disk, the emission reprocessed by the debris into UV/optical, and use X-ray absorption (or emission) features to look at the abundances and the evolution of the kinematics and ionization parameter.

Planetary and satellite x ray spectroscopy: A new window on solid-body composition by remote sensing

NASA Technical Reports Server (NTRS)

Chenette, D. L.; Wolcott, R. W.; Selesnick, R. S.

1993-01-01

The rings and most of the satellites of the outer planets orbit within the radiation belts of their parent bodies. This is an environment with intense fluxes of energetic electrons. As a result, these objects are strong emitters of X-rays. The characteristic X-ray lines from these bodies depend on atomic composition, but they are not sensitive to how the material is arranged in compounds or mixtures. X-ray fluorescence spectral analysis has demonstrated its unique value in the laboratory as a qualitative and quantitative analysis tool. This technique has yet to be fully exploited in a planetary instrument for remote sensing. The characteristic X-ray emissions provide atomic relative abundances. These results are complementary to the molecular composition information obtained from IR, visible, and UV emission spectra. The atomic relative abundances are crucial to understanding the formation and evolution of these bodies. They are also crucial to the proper interpretation of the molecular composition results from the other sensors. The intensities of the characteristic X-ray emissions are sufficiently strong to be measured with an instrument of modest size. Recent developments in X-ray detector technologies and electronic miniaturization have made possible space-flight X-ray imaging and nonimaging spectrometers of high sensitivity and excellent energy resolution that are rugged enough to survive long-duration space missions. Depending on the application, such instruments are capable of resolving elemental abundances of elements from carbon through iron. At the same time, by measuring the bremsstrahlung intensity and energy spectrum, the characteristics of the source electron flux can be determined. We will discuss these concepts, including estimated source strengths, and will describe a small instrument capable of providing this unique channel of information for future planetary missions. We propose to build this instrument using innovative electronics packaging

X-ray and gamma ray astronomy detectors

NASA Technical Reports Server (NTRS)

Decher, Rudolf; Ramsey, Brian D.; Austin, Robert

1994-01-01

X-ray and gamma ray astronomy was made possible by the advent of space flight. Discovery and early observations of celestial x-rays and gamma rays, dating back almost 40 years, were first done with high altitude rockets, followed by Earth-orbiting satellites> once it became possible to carry detectors above the Earth's atmosphere, a new view of the universe in the high-energy part of the electromagnetic spectrum evolved. Many of the detector concepts used for x-ray and gamma ray astronomy were derived from radiation measuring instruments used in atomic physics, nuclear physics, and other fields. However, these instruments, when used in x-ray and gamma ray astronomy, have to meet unique and demanding requirements related to their operation in space and the need to detect and measure extremely weak radiation fluxes from celestial x-ray and gamma ray sources. Their design for x-ray and gamma ray astronomy has, therefore, become a rather specialized and rapidly advancing field in which improved sensitivity, higher energy and spatial resolution, wider spectral coverage, and enhanced imaging capabilities are all sought. This text is intended as an introduction to x-ray and gamma ray astronomy instruments. It provides an overview of detector design and technology and is aimed at scientists, engineers, and technical personnel and managers associated with this field. The discussion is limited to basic principles and design concepts and provides examples of applications in past, present, and future space flight missions.

Development of polycapillary x-ray optics for x-ray spectroscopy

NASA Astrophysics Data System (ADS)

Adams, Bernhard W.; Attenkofer, Klaus; Bond, Justin L.; Craven, Christopher A.; Cremer, Till; O'Mahony, Aileen; Minot, Michael J.; Popecki, Mark A.

2016-09-01

Bundles of hollow glass capillaries can be tapered to produce quasi-focusing x-ray optics. These optics are known as Kumakhov lenses. These optics are interesting for lab-based sources because they can be used to collimate and concentrate x-rays originating from a point, such as a laser focus or an electron-beam focus in a microtube.

Distinct charge dynamics in battery electrodes revealed by in situ and operando soft X-ray spectroscopy

PubMed Central

Liu, Xiaosong; Wang, Dongdong; Liu, Gao; Srinivasan, Venkat; Liu, Zhi; Hussain, Zahid; Yang, Wanli

2013-01-01

Developing high-performance batteries relies on material breakthroughs. During the past few years, various in situ characterization tools have been developed and have become indispensible in studying and the eventual optimization of battery materials. However, soft X-ray spectroscopy, one of the most sensitive probes of electronic states, has been mainly limited to ex situ experiments for battery research. Here we achieve in situ and operando soft X-ray absorption spectroscopy of lithium-ion battery cathodes. Taking advantage of the elemental, chemical and surface sensitivities of soft X-rays, we discover distinct lithium-ion and electron dynamics in Li(Co1/3Ni1/3Mn1/3)O2 and LiFePO4 cathodes in polymer electrolytes. The contrast between the two systems and the relaxation effect in LiFePO4 is attributed to a phase transformation mechanism, and the mesoscale morphology and charge conductivity of the electrodes. These discoveries demonstrate feasibility and power of in situ soft X-ray spectroscopy for studying integrated and dynamic effects in batteries. PMID:24100759

Ab initio simulation of diffractometer instrumental function for high-resolution X-ray diffraction1

PubMed Central

Mikhalychev, Alexander; Benediktovitch, Andrei; Ulyanenkova, Tatjana; Ulyanenkov, Alex

2015-01-01

Modeling of the X-ray diffractometer instrumental function for a given optics configuration is important both for planning experiments and for the analysis of measured data. A fast and universal method for instrumental function simulation, suitable for fully automated computer realization and describing both coplanar and noncoplanar measurement geometries for any combination of X-ray optical elements, is proposed. The method can be identified as semi-analytical backward ray tracing and is based on the calculation of a detected signal as an integral of X-ray intensities for all the rays reaching the detector. The high speed of calculation is provided by the expressions for analytical integration over the spatial coordinates that describe the detection point. Consideration of the three-dimensional propagation of rays without restriction to the diffraction plane provides the applicability of the method for noncoplanar geometry and the accuracy for characterization of the signal from a two-dimensional detector. The correctness of the simulation algorithm is checked in the following two ways: by verifying the consistency of the calculated data with the patterns expected for certain simple limiting cases and by comparing measured reciprocal-space maps with the corresponding maps simulated by the proposed method for the same diffractometer configurations. Both kinds of tests demonstrate the agreement of the simulated instrumental function shape with the measured data. PMID:26089760

Electronic Structure of the Organic Semiconductor Alq3 (aluminum tris-8-hydroxyquinoline) from Soft X-ray Spectroscopies and Density Functional Theory Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeMasi, A.; Piper, L; Zhang, Y

2008-01-01

The element-specific electronic structure of the organic semiconductor aluminum tris-8-hydroxyquinoline (Alq3) has been studied using a combination of resonant x-ray emission spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and density functional theory (DFT) calculations. Resonant and nonresonant x-ray emission spectroscopy were used to measure directly the carbon, nitrogen and oxygen 2p partial densities of states in Alq3, and good agreement was found with the results of DFT calculations. Furthermore, resonant x-ray emission at the carbon K-edge is shown to be able to measure the partial density of states associated with individual C sites. Finally, comparison of previous x-ray emission studiesmore » and the present data reveal the presence of clear photon-induced damage in the former.« less

Electronic structure of the organic semiconductor Alq3 (aluminum tris-8-hydroxyquinoline) from soft x-ray spectroscopies and density functional theory calculations.

PubMed

DeMasi, A; Piper, L F J; Zhang, Y; Reid, I; Wang, S; Smith, K E; Downes, J E; Peltekis, N; McGuinness, C; Matsuura, A

2008-12-14

The element-specific electronic structure of the organic semiconductor aluminum tris-8-hydroxyquinoline (Alq(3)) has been studied using a combination of resonant x-ray emission spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and density functional theory (DFT) calculations. Resonant and nonresonant x-ray emission spectroscopy were used to measure directly the carbon, nitrogen and oxygen 2p partial densities of states in Alq(3), and good agreement was found with the results of DFT calculations. Furthermore, resonant x-ray emission at the carbon K-edge is shown to be able to measure the partial density of states associated with individual C sites. Finally, comparison of previous x-ray emission studies and the present data reveal the presence of clear photon-induced damage in the former.

In Situ Identification of Mineral Resources with an X-Ray-Optical "Hands-Lens" Instrument

NASA Technical Reports Server (NTRS)

Marshall, J.; Koppel, L.; Bratton, C.; Metzger, E.; Hecht, M.

1999-01-01

The recognition of material resources on a planetary surface requires exploration strategies not dissimilar to those employed by early field geologists who searched for ore deposits primarily from surface clues. In order to determine the location of mineral ores or other materials, it will be necessary to characterize host terranes at regional or subregional scales. This requires geographically broad surveys in which statistically significant numbers of samples are rapidly scanned from a roving platform. To enable broad-scale, yet power-conservative planetary-surface exploration, we are developing an instrument that combines x-ray diffractometry (XRD), x-ray fluorescence spectrometry (XRF), and optical capabilities; the instrument can be deployed at the end of a rover's robotic arm, without the need for sample capture or preparation. The instrument provides XRD data for identification of mineral species and lithological types; diffractometry of minerals is conducted by ascertaining the characteristic lattice parameters or "d-spacings" of mineral compounds. D-spacings of 1.4 to 25 angstroms can be determined to include the large molecular structures of hydrated minerals such as clays. The XRF data will identify elements ranging from carbon (Atomic Number = 6) to elements as heavy as barium (Atomic Number = 56). While a sample is being x-rayed, the instrument simultaneously acquires an optical image of the sample surface at magnifications from lx to at least 50x (200x being feasible, depending on the sample surface). We believe that imaging the sample is extremely important as corroborative sample-identification data (the need for this capability having been illustrated by the experience of the Pathfinder rover). Very few geologists would rely on instrument data for sample identification without having seen the sample. Visual inspection provides critical recognition data such as texture, crystallinity, granularity, porosity, vesicularity, color, lustre, opacity, and

In Situ Identification of Mineral Resources with an X-Ray-Optical "Hands-Lens" Instrument

NASA Astrophysics Data System (ADS)

Marshall, J.; Koppel, L.; Bratton, C.; Metzger, E.; Hecht, M.

1999-09-01

The recognition of material resources on a planetary surface requires exploration strategies not dissimilar to those employed by early field geologists who searched for ore deposits primarily from surface clues. In order to determine the location of mineral ores or other materials, it will be necessary to characterize host terranes at regional or subregional scales. This requires geographically broad surveys in which statistically significant numbers of samples are rapidly scanned from a roving platform. To enable broad-scale, yet power-conservative planetary-surface exploration, we are developing an instrument that combines x-ray diffractometry (XRD), x-ray fluorescence spectrometry (XRF), and optical capabilities; the instrument can be deployed at the end of a rover's robotic arm, without the need for sample capture or preparation. The instrument provides XRD data for identification of mineral species and lithological types; diffractometry of minerals is conducted by ascertaining the characteristic lattice parameters or "d-spacings" of mineral compounds. D-spacings of 1.4 to 25 angstroms can be determined to include the large molecular structures of hydrated minerals such as clays. The XRF data will identify elements ranging from carbon (Atomic Number = 6) to elements as heavy as barium (Atomic Number = 56). While a sample is being x-rayed, the instrument simultaneously acquires an optical image of the sample surface at magnifications from lx to at least 50x (200x being feasible, depending on the sample surface). We believe that imaging the sample is extremely important as corroborative sample-identification data (the need for this capability having been illustrated by the experience of the Pathfinder rover). Very few geologists would rely on instrument data for sample identification without having seen the sample. Visual inspection provides critical recognition data such as texture, crystallinity, granularity, porosity, vesicularity, color, lustre, opacity, and

Extended x-ray absorption fine structure spectroscopy and x-ray absorption near edge spectroscopy study of aliovalent doped ceria to correlate local structural changes with oxygen vacancies clustering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shirbhate, S. C.; Acharya, S. A., E-mail: saha275@yahoo.com; Yadav, A. K.

2016-04-04

This study provides atomic scale insight to understand the role of aliovalent dopants on oxygen vacancies clustering and dissociation mechanism in ceria system in order to enhance the performance of oxy-ion conductor. Dopants induced microscale changes in ceria are probed by extended X-ray absorption fine structure spectroscopy, X-ray absorption near edge spectra, and Raman spectroscopy. The results are explored to establish a correlation between atomic level structural changes (coordination number, interatomic spacing) → formation of dimer and trimer type cation-oxygen vacancies defect complex (intrinsic and extrinsic) → dissociation of oxygen vacancies from defect cluster → ionic conductivity temperature. It ismore » a strategic approach to understand key physics of ionic conductivity mechanism in order to reduce operating temperature of electrolytes for intermediate temperature (300–450 °C) electrochemical devices for the first time.« less

A time-correlation function approach to nuclear dynamical effects in X-ray spectroscopy.

PubMed

Karsten, Sven; Bokarev, Sergey I; Aziz, Saadullah G; Ivanov, Sergei D; Kühn, Oliver

2017-06-14

Modern X-ray spectroscopy has proven itself as a robust tool for probing the electronic structure of atoms in complex environments. Despite working on energy scales that are much larger than those corresponding to nuclear motions, taking nuclear dynamics and the associated nuclear correlations into account may be of importance for X-ray spectroscopy. Recently, we have developed an efficient protocol to account for nuclear dynamics in X-ray absorption and resonant inelastic X-ray scattering spectra [Karsten et al., J. Phys. Chem. Lett. 8, 992 (2017)], based on ground state molecular dynamics accompanied with state-of-the-art calculations of electronic excitation energies and transition dipoles. Here, we present an alternative derivation of the formalism and elaborate on the developed simulation protocol using gas phase and bulk water as examples. The specific spectroscopic features stemming from the nuclear motions are analyzed and traced down to the dynamics of electronic energy gaps and transition dipole correlation functions. The observed tendencies are explained on the basis of a simple harmonic model, and the involved approximations are discussed. The method represents a step forward over the conventional approaches that treat the system in full complexity and provides a reasonable starting point for further improvements.

A time-correlation function approach to nuclear dynamical effects in X-ray spectroscopy

NASA Astrophysics Data System (ADS)

Karsten, Sven; Bokarev, Sergey I.; Aziz, Saadullah G.; Ivanov, Sergei D.; Kühn, Oliver

2017-06-01

Modern X-ray spectroscopy has proven itself as a robust tool for probing the electronic structure of atoms in complex environments. Despite working on energy scales that are much larger than those corresponding to nuclear motions, taking nuclear dynamics and the associated nuclear correlations into account may be of importance for X-ray spectroscopy. Recently, we have developed an efficient protocol to account for nuclear dynamics in X-ray absorption and resonant inelastic X-ray scattering spectra [Karsten et al., J. Phys. Chem. Lett. 8, 992 (2017)], based on ground state molecular dynamics accompanied with state-of-the-art calculations of electronic excitation energies and transition dipoles. Here, we present an alternative derivation of the formalism and elaborate on the developed simulation protocol using gas phase and bulk water as examples. The specific spectroscopic features stemming from the nuclear motions are analyzed and traced down to the dynamics of electronic energy gaps and transition dipole correlation functions. The observed tendencies are explained on the basis of a simple harmonic model, and the involved approximations are discussed. The method represents a step forward over the conventional approaches that treat the system in full complexity and provides a reasonable starting point for further improvements.

The X-Ray Polarimeter Instrument on Board the Polarimeter for Relativistic Astrophysical X-Ray Sources (PRAXyS) Mission

NASA Technical Reports Server (NTRS)

Hill, J. E.; Black, J. K.; Jahoda, K.; Tamagawa, T.; Iwakiri, W.; Kitaguchi, T.; Kubota, M.; Kaaret, P.; Mccurdy, R.; Miles, D. M.;

Tracking reaction dynamics in solution by pump-probe X-ray absorption spectroscopy and X-ray liquidography (solution scattering).

PubMed

Kim, Jeongho; Kim, Kyung Hwan; Oang, Key Young; Lee, Jae Hyuk; Hong, Kiryong; Cho, Hana; Huse, Nils; Schoenlein, Robert W; Kim, Tae Kyu; Ihee, Hyotcherl

2016-03-07

Characterization of transient molecular structures formed during chemical and biological processes is essential for understanding their mechanisms and functions. Over the last decade, time-resolved X-ray liquidography (TRXL) and time-resolved X-ray absorption spectroscopy (TRXAS) have emerged as powerful techniques for molecular and electronic structural analysis of photoinduced reactions in the solution phase. Both techniques make use of a pump-probe scheme that consists of (1) an optical pump pulse to initiate a photoinduced process and (2) an X-ray probe pulse to monitor changes in the molecular structure as a function of time delay between pump and probe pulses. TRXL is sensitive to changes in the global molecular structure and therefore can be used to elucidate structural changes of reacting solute molecules as well as the collective response of solvent molecules. On the other hand, TRXAS can be used to probe changes in both local geometrical and electronic structures of specific X-ray-absorbing atoms due to the element-specific nature of core-level transitions. These techniques are complementary to each other and a combination of the two methods will enhance the capability of accurately obtaining structural changes induced by photoexcitation. Here we review the principles of TRXL and TRXAS and present recent application examples of the two methods for studying chemical and biological processes in solution. Furthermore, we briefly discuss the prospect of using X-ray free electron lasers for the two techniques, which will allow us to keep track of structural dynamics on femtosecond time scales in various solution-phase molecular reactions.

Spatially resolved high resolution x-ray spectroscopy for magnetically confined fusion plasmas (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ince-Cushman, A.; Rice, J. E.; Reinke, M. L.

2008-10-15

The use of high resolution x-ray crystal spectrometers to diagnose fusion plasmas has been limited by the poor spatial localization associated with chord integrated measurements. Taking advantage of a new x-ray imaging spectrometer concept [M. Bitter et al., Rev. Sci. Instrum. 75, 3660 (2004)], and improvements in x-ray detector technology [Ch. Broennimann et al., J. Synchrotron Radiat. 13, 120 (2006)], a spatially resolving high resolution x-ray spectrometer has been built and installed on the Alcator C-Mod tokamak. This instrument utilizes a spherically bent quartz crystal and a set of two dimensional x-ray detectors arranged in the Johann configuration [H. H.more » Johann, Z. Phys. 69, 185 (1931)] to image the entire plasma cross section with a spatial resolution of about 1 cm. The spectrometer was designed to measure line emission from H-like and He-like argon in the wavelength range 3.7 and 4.0 A with a resolving power of approximately 10 000 at frame rates up to 200 Hz. Using spectral tomographic techniques [I. Condrea, Phys. Plasmas 11, 2427 (2004)] the line integrated spectra can be inverted to infer profiles of impurity emissivity, velocity, and temperature. From these quantities it is then possible to calculate impurity density and electron temperature profiles. An overview of the instrument, analysis techniques, and example profiles are presented.« less

Chemical Modification of Graphene Oxide by Nitrogenation: An X-ray Absorption and Emission Spectroscopy Study

NASA Astrophysics Data System (ADS)

Chuang, Cheng-Hao; Ray, Sekhar C.; Mazumder, Debarati; Sharma, Surbhi; Ganguly, Abhijit; Papakonstantinou, Pagona; Chiou, Jau-Wern; Tsai, Huang-Ming; Shiu, Hung-Wei; Chen, Chia-Hao; Lin, Hong-Ji; Guo, Jinghua; Pong, Way-Faung

2017-02-01

Nitrogen-doped graphene oxides (GO:Nx) were synthesized by a partial reduction of graphene oxide (GO) using urea [CO(NH2)2]. Their electronic/bonding structures were investigated using X-ray absorption near-edge structure (XANES), valence-band photoemission spectroscopy (VB-PES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). During GO:Nx synthesis, different nitrogen-bonding species, such as pyrrolic/graphitic-nitrogen, were formed by replacing of oxygen-containing functional groups. At lower N-content (2.7 at%), pyrrolic-N, owing to surface and subsurface diffusion of C, N and NH is deduced from various X-ray spectroscopies. In contrast, at higher N-content (5.0 at%) graphitic nitrogen was formed in which each N-atom trigonally bonds to three distinct sp2-hybridized carbons with substitution of the N-atoms for C atoms in the graphite layer. Upon nitrogen substitution, the total density of state close to Fermi level is increased to raise the valence-band maximum, as revealed by VB-PES spectra, indicating an electron donation from nitrogen, molecular bonding C/N/O coordination or/and lattice structure reorganization in GO:Nx. The well-ordered chemical environments induced by nitrogen dopant are revealed by XANES and RIXS measurements.

Investigation of nanoparticulate silicon as printed layers using scanning electron microscopy, transmission electron microscopy, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy

DOE PAGES

Unuigbe, David M.; Harting, Margit; Jonah, Emmanuel O.; ...

2017-08-21

The presence of native oxide on the surface of silicon nanoparticles is known to inhibit charge transport on the surfaces. Scanning electron microscopy (SEM) studies reveal that the particles in the printed silicon network have a wide range of sizes and shapes. High-resolution transmission electron microscopy reveals that the particle surfaces have mainly the (111)- and (100)-oriented planes which stabilizes against further oxidation of the particles. X-ray absorption spectroscopy (XANES) and X-ray photoelectron spectroscopy (XPS) measurements at the O 1s-edge have been utilized to study the oxidation and local atomic structure of printed layers of silicon nanoparticles which were milledmore » for different times. XANES results reveal the presence of the +4 (SiO 2) oxidation state which tends towards the +2 (SiO) state for higher milling times. Si 2pXPS results indicate that the surfaces of the silicon nanoparticles in the printed layers are only partially oxidized and that all three sub-oxide, +1 (Si 2O), +2 (SiO) and +3 (Si 2O 3), states are present. The analysis of the change in the sub-oxide peaks of the silicon nanoparticles shows the dominance of the +4 state only for lower milling times.« less

A new generation of x-ray spectrometry UHV instruments at the SR facilities BESSY II, ELETTRA and SOLEIL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lubeck, J., E-mail: janin.lubeck@ptb.de; Fliegauf, R.; Holfelder, I.

A novel type of ultra-high vacuum instrument for X-ray reflectometry and spectrometry-related techniques for nanoanalytics by means of synchrotron radiation (SR) has been constructed and commissioned at BESSY II. This versa-tile instrument was developed by the PTB, Germany’s national metrology institute, and includes a 9-axis manipulator that allows for an independent alignment of the samples with respect to all degrees of freedom. In addition, it integrates a rotational and translational movement of several photodiodes as well as a translational movement of a beam-geometry-defining aperture system. Thus, the new instrument enables various analytical techniques based on energy dispersive X-ray detectors suchmore » as reference-free X-Ray Fluorescence (XRF) analysis, total-reflection XRF, grazing-incidence XRF, in addition to optional X-Ray Reflectometry (XRR) measurements or polarization-dependent X-ray absorption fine structure analyses (XAFS). Samples having a size of up to (100 × 100) mm{sup 2}; can be analyzed with respect to their mass deposition, elemental, spatial or species composition. Surface contamination, nanolayer composition and thickness, depth pro-file of matrix elements or implants, nanoparticles or buried interfaces as well as molecular orientation of bonds can be accessed. Three technology transfer projects of adapted instruments have enhanced X-Ray Spectrometry (XRS) research activities within Europe at the synchrotron radiation facilities ELETTRA (IAEA) and SOLEIL (CEA/LNE-LNHB) as well as at the X-ray innovation laboratory BLiX (TU Berlin) where different laboratory sources are used. Here, smaller chamber requirements led PTB in cooperation with TU Berlin to develop a modified instrument equipped with a 7-axis manipulator: reduced freedom in the choice of experimental geometry modifications (absence of out-of-SR-plane and reference-free XRS options) has been compensated by encoder-enhanced angular accuracy for GIXRF and XRR.« less

Near- and Extended-Edge X-Ray-Absorption Fine-Structure Spectroscopy Using Ultrafast Coherent High-Order Harmonic Supercontinua

NASA Astrophysics Data System (ADS)

Popmintchev, Dimitar; Galloway, Benjamin R.; Chen, Ming-Chang; Dollar, Franklin; Mancuso, Christopher A.; Hankla, Amelia; Miaja-Avila, Luis; O'Neil, Galen; Shaw, Justin M.; Fan, Guangyu; Ališauskas, Skirmantas; Andriukaitis, Giedrius; Balčiunas, Tadas; Mücke, Oliver D.; Pugzlys, Audrius; Baltuška, Andrius; Kapteyn, Henry C.; Popmintchev, Tenio; Murnane, Margaret M.

2018-03-01

Recent advances in high-order harmonic generation have made it possible to use a tabletop-scale setup to produce spatially and temporally coherent beams of light with bandwidth spanning 12 octaves, from the ultraviolet up to x-ray photon energies >1.6 keV . Here we demonstrate the use of this light for x-ray-absorption spectroscopy at the K - and L -absorption edges of solids at photon energies near 1 keV. We also report x-ray-absorption spectroscopy in the water window spectral region (284-543 eV) using a high flux high-order harmonic generation x-ray supercontinuum with 109 photons/s in 1% bandwidth, 3 orders of magnitude larger than has previously been possible using tabletop sources. Since this x-ray radiation emerges as a single attosecond-to-femtosecond pulse with peak brightness exceeding 1026 photons/s /mrad2/mm2/1 % bandwidth, these novel coherent x-ray sources are ideal for probing the fastest molecular and materials processes on femtosecond-to-attosecond time scales and picometer length scales.

Characterization of Colloidal Quantum Dot Ligand Exchange by X-ray Photoelectron Spectroscopy

NASA Astrophysics Data System (ADS)

Atewologun, Ayomide; Ge, Wangyao; Stiff-Roberts, Adrienne D.

2013-05-01

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.

UV-Visible Absorption Spectroscopy Enhanced X-ray Crystallography at Synchrotron and X-ray Free Electron Laser Sources.

PubMed

Cohen, Aina E; Doukov, Tzanko; Soltis, Michael S

2016-01-01

This review describes the use of single crystal UV-Visible Absorption micro-Spectrophotometry (UV-Vis AS) to enhance the design and execution of X-ray crystallography experiments for structural investigations of reaction intermediates of redox active and photosensitive proteins. Considerations for UV-Vis AS measurements at the synchrotron and associated instrumentation are described. UV-Vis AS is useful to verify the intermediate state of an enzyme and to monitor the progression of reactions within crystals. Radiation induced redox changes within protein crystals may be monitored to devise effective diffraction data collection strategies. An overview of the specific effects of radiation damage on macromolecular crystals is presented along with data collection strategies that minimize these effects by combining data from multiple crystals used at the synchrotron and with the X-ray free electron laser.

A novel von Hamos spectrometer for efficient X-ray emission spectroscopy in the laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anklamm, Lars, E-mail: anklamm@physik.tu-berlin.de; Schlesiger, Christopher; Malzer, Wolfgang

2014-05-15

We present a novel, highly efficient von Hamos spectrometer for X-ray emission spectroscopy (XES) in the laboratory using highly annealed pyrolitic graphite crystals as the dispersive element. The spectrometer covers an energy range from 2.5 keV to 15 keV giving access to chemical speciation and information about the electronic configuration of 3d transition metals by means of the Kβ multiplet. XES spectra of Ti compounds are presented to demonstrate the speciation capabilities of the instrument. A spectral resolving power of E/ΔE = 2000 at 8 keV was achieved. Typical acquisition times range from 10 min for bulk material to hours formore » thin samples below 1 μm.« less

A structural study of bone changes in knee osteoarthritis by synchrotron-based X-ray fluorescence and X-ray absorption spectroscopy techniques

NASA Astrophysics Data System (ADS)

Sindhupakorn, Bura; Thienpratharn, Suwittaya; Kidkhunthod, Pinit

2017-10-01

Osteoarthritis (OA) is characterized by degeneration of articular cartilage and thickening of subchondral bone. The present study investigated the changing of biochemical components of cartilage and bone compared between normal and OA people. Using Synchrotron-based X-ray fluorescence (SR-XRF) and X-ray absorption spectroscopy (XAS) techniquesincluding X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) were employed for the bone changes in kneeosteoarthritisstudies. The bone samples were collected from various osteoarthritis patients with both male and female in the ages range between 20 and 74 years old. SR-XRF results excited at 4240 eV for Ca elements show a majority three main groups, based on their XRF intensities, 20-36 years, 40-60 years and over 70 years, respectively. By employing XAS techniques, XANES features can be used to clearly explain in term of electronic transitions occurring in bone samples which are affected from osteoarthritis symptoms. Moreover, a structural change around Ca ions in bone samples is obviously obtained by EXAFS results indicating an increase of Ca-amorphous phase when the ages increase.

5.8 X-ray Calorimeters

NASA Technical Reports Server (NTRS)

Porter, F. Scott

2008-01-01

X-ray calorimeter instruments for astrophysics have seen rapid development since they were invented in 1984. The prime instrument on all currently planned X-ray spectroscopic observatories is based on calorimeter technology. This relatively simple detection concept that senses the energy of an incident photon by measuring the temperature rise of an absorber material at very low temperatures, can form the basis of a very high performance, non-dispersive spectrometer. State-of-the-art calorimeter instruments have resolving powers of over 3000, large simultaneous band-passes, and near unit efficiency. This coupled with the intrinsic imaging capability of a pixilated x-ray calorimeter array, allows true spectral-spatial instruments to be constructed. In this chapter I briefly review the detection scheme, the state-of-the-art in X-ray calorimeter instruments and the future outlook for this technology.

Impact of Oriented Clay Particles on X-Ray Spectroscopy Analysis

NASA Astrophysics Data System (ADS)

Lim, A. J. M. S.; Syazwani, R. N.; Wijeyesekera, D. C.

2016-07-01

Understanding the engineering properties of the mineralogy and microfabic of clayey soils is very complex and thus very difficult for soil characterization. Micromechanics of soils recognize that the micro structure and mineralogy of clay have a significant influence on its engineering behaviour. To achieve a more reliable quantitative evaluation of clay mineralogy, a proper sample preparation technique for quantitative clay mineral analysis is necessary. This paper presents the quantitative evaluation of elemental analysis and chemical characterization of oriented and random oriented clay particles using X-ray spectroscopy. Three different types of clays namely marine clay, bentonite and kaolin clay were studied. The oriented samples were prepared by placing the dispersed clay in water and left to settle on porous ceramic tiles by applying a relatively weak suction through a vacuum pump. Images form a Scanning Electron Microscope (SEM) was also used to show the comparison between the orientation patterns of both the sample preparation techniques. From the quantitative analysis of the X-ray spectroscopy, oriented sampling method showed more accuracy in identifying mineral deposits, because it produced better peak intensity on the spectrum and more mineral content can be identified compared to randomly oriented samples.

Very high resolution UV and X-ray spectroscopy and imagery of solar active regions

NASA Technical Reports Server (NTRS)

Bruner, M.; Brown, W. A.; Haisch, B. M.

1987-01-01

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.

The Advanced X-Ray Astrophysics Facility. Observing the Universe in X-Rays

NASA Technical Reports Server (NTRS)

Neal, V.

1984-01-01

An overview of the Advanced X ray Astronophysics Facility (AXAF) program is presented. Beginning with a brief introduction to X ray astrophysics, the AXAF observatory is described including the onboard instrumentation and system capabilities. Possible X ray sources suitable for AXAF observation are identified and defined.

Cryogen-free operation of the Soft X-ray Spectrometer instrument

NASA Astrophysics Data System (ADS)

Sneiderman, Gary A.; Shirron, Peter J.; Fujimoto, Ryuichi; Bialas, Thomas G.; Boyce, Kevin R.; Chiao, Meng P.; DiPirro, Michael J.; Eckart, Megan E.; Hartz, Leslie; Ishisaki, Yoshitaka; Kelley, Richard L.; Kilbourne, Caroline A.; Masters, Candace; McCammon, Dan; Mitsuda, Kazuhisa; Noda, Hirofumi; Porter, Frederick S.; Szymkowiak, Andrew E.; Takei, Yoh; Tsujimoto, Masahiro; Yoshida, Seiji

2016-07-01

The Soft X-ray Spectrometer (SXS) is the first space-based instrument to implement redundancy in the operation of a sub-Kelvin refrigerator. The SXS cryogenic system consists of a superfluid helium tank and a combination of Stirling and Joule-Thompson (JT) cryocoolers that support the operation of a 3-stage adiabatic demagnetization refrigerator (ADR). When liquid helium is present, the x-ray microcalorimeter detectors are cooled to their 50 mK operating temperature by two ADR stages, which reject their heat directly to the liquid at 1.1 K. When the helium is depleted, all three ADR stages are used to accomplish detector cooling while rejecting heat to the JT cooler operating at 4.5 K. Compared to the simpler helium mode operation, the cryogen-free mode achieves the same instrument performance by controlling the active cooling devices within the cooling system differently. These include the three ADR stages and four active heat switches, provided by NASA, and five cryocoolers, provided by JAXA. Development and verification details of this capability are presented within this paper and offer valuable insights into the challenges, successes, and lessons that can benefit other missions, particularly those employing cryogen-free cooling systems.

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

PubMed

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

2016-07-11

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

Feasibility of an integrated X-ray instrument for Mars exobiology and geology. [Abstract only

NASA Technical Reports Server (NTRS)

Fonda, M. L.; Schwartz, D. E.; Koppel, L. N.; Franco, E. D.; Kerner, J. A.

1994-01-01

By employing an integrated X-ray instrument on a future Mars mission, data obtained will greatly augment those returned by Viking; details relevant to the possibility of the origin and evolution of life on Mars will be acquired. An integrated combined X Ray Fluorescence/X Ray Detection (XRF/XRD) instrument has been breadboarded and demonstrated to accommodate important exobiology and geology experiment objectives outlined for Mars Environmental Survey (MESUR) and future Mars missions. Among others, primary objectives for the exploration of Mars include: the intense study of local areas on Mars to 'establish the chemical, mineralogical, and petrological character of different components of the surface material; to determine the distribution, abundance and sources and sinks of volatile materials, including an assessment of the biologic potential, now and during past epochs; and to establish the global chemical and physical characteristics of the Martian surface'. The XRF/XRD breadboard instrument identifies and quantifies soil surface elemental, mineralogical, and petrological characteristics and acquires data necessary to address questions on volatile abundance and distribution. Additionally, the breadboard is able to characterize the biogenic element constituents of soil samples providing information on the biologic potential of the Mars environment.

X-ray Fluorescence Spectroscopy of Pre-Federal American Currency

NASA Astrophysics Data System (ADS)

Raddell, Mark; Manukyan, Khachatur; Aprahamian, Ani; Wiescher, Michael; Jordan, Louis

2017-09-01

X-ray Fluorescence Spectroscopy (XRF) was used to study 17th and 18th century Mexican, Potosí, and Massachusetts silver colonial coins from the University of Notre Dame's Rare Books and Special Collections. Using different configurations and devices, we have learned more about the limitations and optimizations of the method. We have developed a moveable stand that may be used for XRF mapping of coin surfaces. We created standard silver alloy materials for quantification of the elemental composition of the coins. Inductively coupled plasma (ICP) spectroscopy was applied to determine the precise composition of the standards for accurate and non-destructive analyses of the colonial coins. XRF measurements were performed using two different XRF spectrometers, in both air and vacuum conditions, as well as an x-ray beam tube of varying diameters from 2 mm, 1 mm, and 0.03 mm. We quantified both the major elements and the bulk and surface impurities for 90 coins. We are using PCA to look at possible correlations between compositions of coinage from different geographical regions. Preliminary data analyses suggest that Massachusetts coins were minted using silver from Latin American sources. These results are of great interest to historians in tracing the origins of the currency. This work was made possible by the Notre Dame College of Science Summer Undergraduate Research Fellowships (COS-SURF).

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Said, A. H.; Sinn, H.; Divan, R.

2011-05-01

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.

The CAT-ACT Beamline at ANKA: A new high energy X-ray spectroscopy facility for CATalysis and ACTinide research

NASA Astrophysics Data System (ADS)

Zimina, A.; Dardenne, K.; Denecke, M. A.; Grunwaldt, J. D.; Huttel, E.; Lichtenberg, H.; Mangold, S.; Pruessmann, T.; Rothe, J.; Steininger, R.; Vitova, T.

2016-05-01

A new hard X-ray beamline for CATalysis and ACTinide research has been built at the synchrotron radiation facility ANKA. The beamline design is dedicated to X-ray spectroscopy, including ‘flux hungry’ photon-in/photon-out and correlative techniques with a special infrastructure for radionuclide and catalysis research. The CAT-ACT beamline will help serve the growing need for high flux/hard X-ray spectroscopy in these communities. The design, the first spectra and the current status of this project are reported.

Clocking Femtosecond Collisional Dynamics via Resonant X-Ray Spectroscopy

NASA Astrophysics Data System (ADS)

van den Berg, Q. Y.; Fernandez-Tello, E. V.; Burian, T.; Chalupský, J.; Chung, H.-K.; Ciricosta, O.; Dakovski, G. L.; Hájková, V.; Hollebon, P.; Juha, L.; Krzywinski, J.; Lee, R. W.; Minitti, M. P.; Preston, T. R.; de la Varga, A. G.; Vozda, V.; Zastrau, U.; Wark, J. S.; Velarde, P.; Vinko, S. M.

2018-02-01

Electron-ion collisional dynamics is of fundamental importance in determining plasma transport properties, nonequilibrium plasma evolution, and electron damage in diffraction imaging applications using bright x-ray free-electron lasers (FELs). Here we describe the first experimental measurements of ultrafast electron impact collisional ionization dynamics using resonant core-hole spectroscopy in a solid-density magnesium plasma, created and diagnosed with the Linac Coherent Light Source x-ray FEL. By resonantly pumping the 1 s →2 p transition in highly charged ions within an optically thin plasma, we have measured how off-resonance charge states are populated via collisional processes on femtosecond time scales. We present a collisional cross section model that matches our results and demonstrates how the cross sections are enhanced by dense-plasma effects including continuum lowering. Nonlocal thermodynamic equilibrium collisional radiative simulations show excellent agreement with the experimental results and provide new insight on collisional ionization and three-body-recombination processes in the dense-plasma regime.

Time-resolved x-ray absorption spectroscopy: Watching atoms dance

NASA Astrophysics Data System (ADS)

Milne, Chris J.; Pham, Van-Thai; Gawelda, Wojciech; van der Veen, Renske M.; El Nahhas, Amal; Johnson, Steven L.; Beaud, Paul; Ingold, Gerhard; Lima, Frederico; Vithanage, Dimali A.; Benfatto, Maurizio; Grolimund, Daniel; Borca, Camelia; Kaiser, Maik; Hauser, Andreas; Abela, Rafael; Bressler, Christian; Chergui, Majed

2009-11-01

The introduction of pump-probe techniques to the field of x-ray absorption spectroscopy (XAS) has allowed the monitoring of both structural and electronic dynamics of disordered systems in the condensed phase with unprecedented accuracy, both in time and in space. We present results on the electronically excited high-spin state structure of an Fe(II) molecular species, [FeII(bpy)3]2+, in aqueous solution, resolving the Fe-N bond distance elongation as 0.2 Å. In addition an analysis technique using the reduced χ2 goodness of fit between FEFF EXAFS simulations and the experimental transient absorption signal in energy space has been successfully tested as a function of excited state population and chemical shift, demonstrating its applicability in situations where the fractional excited state population cannot be determined through other measurements. Finally by using a novel ultrafast hard x-ray 'slicing' source the question of how the molecule relaxes after optical excitation has been successfully resolved using femtosecond XANES.

Structural studies of homoisoflavonoids: NMR spectroscopy, X-ray diffraction, and theoretical calculations

NASA Astrophysics Data System (ADS)

Sievänen, Elina; Toušek, Jaromír; Lunerová, Kamila; Marek, Jaromír; Jankovská, Dagmar; Dvorská, Margita; Marek, Radek

2010-08-01

In this article we present a detailed structural investigation for five homoisoflavonoids, molecules important from the pharmacological point of view. For studying the electron distribution as well as its influence on the physicochemical properties, NMR spectroscopy, X-ray diffraction, and theoretical calculations have been used. Nuclear magnetic shieldings obtained by using DFT calculations for optimized molecular geometries are correlated with the experimentally determined chemical shifts. The theoretical data are well in agreement with the experimental values. The single crystal X-ray structures of homoisoflavonoid derivatives 1, 3, and 4 have been solved. The molecular geometries and crystal packing determined by X-ray diffraction are used for characterizing the intermolecular interactions. Electron distribution is crucial for the stability of radicals and hence the antioxidant efficiency of flavonoid structures. The hydrogen bonding governs the formation of complexes of homoisoflavonoids with biological targets.

Centaurus X-3. [early x-ray binary star spectroscopy

NASA Technical Reports Server (NTRS)

Hutchings, J. B.; Cowley, A. P.; Crampton, D.; Van Paradus, J.; White, N. E.

1979-01-01

Spectroscopic observations of Krzeminski's star at dispersions 25-60 A/mm are described. The primary is an evolved star of type O6-O8(f) with peculiarities, some of which are attributable to X-ray heating. Broad emission lines at 4640A (N III), 4686 A(He II) and H-alpha show self-absorption and do not originate entirely from the region near the X-ray star. The primary is not highly luminous (bolometric magnitude about -9) and does not show signs of an abnormally strong stellar wind. The X-ray source was 'on' at the time of optical observations. Orbital parameters are presented for the primary, which yield masses of 17 + or - 2 and 1.0 + or - 3 solar masses for the stars. The optical star is undermassive for its luminosity, as are other OB-star X-ray primaries. The rotation is probably synchronized with the orbital motion. The distance to Cen X-3 is estimated to be 10 + or - 1 kpc. Basic data for 12 early-type X-ray primaries are discussed briefly

Inter-diffusion of copper and hafnium as studied by x-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Pearson, Justin; Chourasia, A. R.

The Cu/Hf interface has been characterized by x-ray photoelectron spectroscopy. Thin films (thicknesses ranging from 100 nm to 150 nm) of hafnium were deposited on a silicon substrate. About 80 nm of copper was then deposited on such samples. The e-beam method was used for the deposition. The samples were annealed for 30 min at temperatures of 100, 200, 300, 400, and 500°C. The inter-diffusion of copper and hafnium was investigated by sequential sputter depth profiling and x-ray photoelectron spectroscopy. The interdiffusion in each case was analyzed by the Matano-Boltzmann's procedure using the Fick's second law. The interdiffusion coefficients and the width of the interface as determined from the data have been correlated with the annealing temperature. Supported by Organized Research, TAMU-Commerce.

Nm-scale spatial resolution x-ray imaging with MLL nanofocusing optics: instrumentational requirements and challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazaretski, E.; Yan, H.; Lauer, K.

2016-08-30

The Hard X-ray Nanoprobe (HXN) beamline at NSLS-II has been designed and constructed to enable imaging experiments with unprecedented spatial resolution and detection sensitivity. The HXN X-ray Microscope is a key instrument for the beamline, providing a suite of experimental capabilities which includes scanning fluorescence, diffraction, differential phase contrast and ptychography utilizing Multilayer Laue Lenses (MLL) and zoneplate (ZP) as nanofocusing optics. In this paper, we present technical requirements for the MLL-based scanning microscope, outline the development concept and present first ~15 x 15 nm 2 spatial resolution x-ray fluorescence images.

Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light Source

DOE PAGES

Alonso-Mori, Roberto; Sokaras, Dimosthenis; Zhu, Diling; ...

2015-04-15

X-ray free-electron lasers (FELs) have opened unprecedented possibilities to study the structure and dynamics of matter at an atomic level and ultra-fast timescale. Many of the techniques routinely used at storage ring facilities are being adapted for experiments conducted at FELs. In order to take full advantage of these new sources several challenges have to be overcome. They are related to the very different source characteristics and its resulting impact on sample delivery, X-ray optics, X-ray detection and data acquisition. Here it is described how photon-in photon-out hard X-ray spectroscopy techniques can be applied to study the electronic structure andmore » its dynamics of transition metal systems with ultra-bright and ultra-short FEL X-ray pulses. In particular, some of the experimental details that are different compared with synchrotron-based setups are discussed and illustrated by recent measurements performed at the Linac Coherent Light Source.« less

Evaluation of the medical exposure doses regarding dental examinations with different X-ray instruments

NASA Astrophysics Data System (ADS)

Liu, Yi-Chi; Chuang, Keh-Shih; Yu, Cheng-Ching; Chao, Jiunn-Hsing; Hsu, Fang-Yuh

2015-11-01

Modern dental X-ray examination that consists of traditional form, panorama, and cone-beamed 3D technologies is one of the most frequent diagnostic applications nowadays. This study used the Rando Phantom and thermoluminescence dosimeters (TLD) to measure the absorbed doses of radiosensitive organs recommended by International Commission on Radiological Protection (ICRP), and whole body effective doses which were delivered due to dental X-ray examination performed with different types of X-ray instrument. Besides, enamel samples which performed reading with Electronic Paramagnetic Resonance (EPR) procedure were also used to estimate the tooth doses. EPR is a dose reconstruction method of measuring free radicals induced by radiation exposure to the calcified tissue (mainly in the tooth enamel or bone) to evaluate the accepted high dose. The tooth doses estimated by TLD and EPR methods were compared. Relationships between the tooth doses and effective doses by dental X-ray examinations with different types of X-ray equipment were investigated in this work.

Hydrothermal Diamond Anvil Cell (HDAC): From Visual Observation to X-ray Absorption Spectroscopy

NASA Astrophysics Data System (ADS)

Bassett, W. A.; Mibe, K.

2006-05-01

A fluid sample contained in a Re gasket between two diamond anvils can be subjected to pressures up to 2.5 GPa and temperatures up to 1200°C in a resistively heated hydrothermal diamond anvil cell (HDAC). Thermocouples are used to measure temperature. The constant-volume sample chamber permits isochoric measurements that can be used to determine pressure from the equation of state of H2O and to map phases and properties in P-T space. A movie of reactions between K-feldspar and water up to 2.5 GPa and 880°C illustrates the use of visual observations for mapping coexisting solution, melt, and solid phases. X-ray absorption spectroscopy of ZnBr2 in solution up to 500°C and 500 MPa shows hydrogen bond breaking in the hydration shells of the ZnBr42- and Br- ions with increasing temperature. In other studies the stability field of ikaite (CaCO3·6H2O) has been mapped by visual observation and Raman spectroscopy; the phases of montmorillonite have been mapped by X-ray diffraction; and the leaching of Pb from zircon has been measured by X-ray microprobe.

The nature of 50 Palermo Swift-BAT hard X-ray objects through optical spectroscopy

NASA Astrophysics Data System (ADS)

Rojas, A. F.; Masetti, N.; Minniti, D.; Jiménez-Bailón, E.; Chavushyan, V.; Hau, G.; McBride, V. A.; Bassani, L.; Bazzano, A.; Bird, A. J.; Galaz, G.; Gavignaud, I.; Landi, R.; Malizia, A.; Morelli, L.; Palazzi, E.; Patiño-Álvarez, V.; Stephen, J. B.; Ubertini, P.

2017-06-01

We present the nature of 50 hard X-ray emitting objects unveiled through an optical spectroscopy campaign performed at seven telescopes in the northern and southern hemispheres. These objects were detected with the Burst Alert Telescope (BAT) instrument onboard the Swift satellite and listed as of unidentified nature in the 54-month Palermo BAT catalogue. In detail, 45 sources in our sample are identified as active galactic nuclei of which, 27 are classified as type 1 (with broad and narrow emission lines) and 18 are classified as type 2 (with only narrow emission lines). Among the broad-line emission objects, one is a type 1 high-redshift quasi-stellar object, and among the narrow-line emission objects, one is a starburst galaxy, one is a X-ray bright optically normal galaxy, and one is a low ionization nuclear emission line region. We report 30 new redshift measurements, 13 confirmations and 2 more accurate redshift values. The remaining five objects are galactic sources: three are Cataclismic Variables, one is a X-ray Binary probably with a low mass secondary star, and one is an active star. Based on observations obtained from the following observatories: Cerro Tololo Interamerican Observatory (Chile); Astronomical Observatory of Bologna in Loiano (Italy); Observatorio Astronómico Nacional (San Pedro Mártir, Mexico); Radcliffe telescope of the South African Astronomical Observatory (Sutherland, South Africa); Sloan Digital Sky Survey; Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias (Canary Islands, Spain) and New Technology Telescope (NTT) of La Silla Observatory, Chile.

Characterization and Evolution of the Swift X-ray Telescope Instrumental Background

NASA Technical Reports Server (NTRS)

Hill, Joanne; Pagani, C.; Morris, D. C.; Racusin, J.; Grupe, D.; Vetere, L.; Stroh, M.; Falcone, A.; Kennea, J.; Burrows, D. N.;

Characterization of aluminum nitride based films with high resolution X-ray fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Anagnostopoulos, D. F.; Siozios, A.; Patsalas, P.

2018-02-01

X-ray fluorescence spectra of Al based films are measured, using a lab-scale wavelength dispersive flat crystal spectrometer. Various structures of AlN films were studied, like single layered, capped, stratified, nanostructured, crystalline, or amorphous. By optimizing the set-up for enhanced energy resolution and detection efficiency, the measured line shapes of Κα, Kβ, and KLL radiative Auger transitions are shown to be adequately detailed to allow chemical characterization. The chemistry identification is based on the pattern comparison of the emitted line shape from the chemically unknown film and the reference line shapes from standard materials, recorded under identical experimental conditions. The ultimate strength of lab-scale high resolution X-ray fluorescence spectroscopy on film analysis is verified, in cases that ordinary applied techniques like X-ray photoelectron and X-ray diffraction fail, while the characterization refers to the non-destructive determination of the bulk properties of the film and not to its surface, as the probed depth is in the micrometer range.

Dual crystal x-ray spectrometer at 1.8 keV for high repetition-rate single-photon counting spectroscopy experiments

DOE PAGES

Gamboa, E. J.; Bachmann, B.; Kraus, D.; ...

2016-08-01

The recent development of high-repetition rate x-ray free electron lasers (FEL), makes it possible to perform x-ray scattering and emission spectroscopy measurements from thin foils or gasses heated to high-energy density conditions by integrating over many experimental shots. Since the expected signal may be weaker than the typical CCD readout noise over the region-of-interest, it is critical to the success of this approach to use a detector with high-energy resolution so that single x-ray photons may be isolated. We describe a dual channel x-ray spectrometer developed for the Atomic and Molecular Optics endstation at the Linac Coherent Light Source (LCLS)more » for x-ray spectroscopy near the K-edge of aluminum. The spectrometer is based on a pair of curved PET (002) crystals coupled to a single pnCCD detector which simultaneously measures x-ray scattering and emission in the forward and backward directions. Furthermore, the signals from single x-ray photons are accumulated permitting continuous single-shot acquisition at 120 Hz.« less

The Instruments and Capabilities of the Miniature X-Ray Solar Spectrometer (MinXSS) CubeSats

NASA Astrophysics Data System (ADS)

Moore, Christopher S.; Caspi, Amir; Woods, Thomas N.; Chamberlin, Phillip C.; Dennis, Brian R.; Jones, Andrew R.; Mason, James P.; Schwartz, Richard A.; Tolbert, Anne K.

2018-02-01

The Miniature X-ray Solar Spectrometer (MinXSS) CubeSat is the first solar science oriented CubeSat mission flown for the NASA Science Mission Directorate, with the main objective of measuring the solar soft X-ray (SXR) flux and a science goal of determining its influence on Earth's ionosphere and thermosphere. These observations can also be used to investigate solar quiescent, active region, and flare properties. The MinXSS X-ray instruments consist of a spectrometer, called X123, with a nominal 0.15 keV full-width at half-maximum (FWHM) resolution at 5.9 keV and a broadband X-ray photometer, called XP. Both instruments are designed to obtain measurements from 0.5 - 30 keV at a nominal time cadence of 10 s. A description of the MinXSS instruments, performance capabilities, and relation to the Geostationary Operational Environmental Satellite (GOES) 0.1 - 0.8 nm flux is given in this article. Early MinXSS results demonstrate the capability of measuring variations of the solar spectral soft X-ray (SXR) flux between 0.8 - 12 keV from at least GOES A5-M5 (5 × 10^{-8} - 5 ×10^{-5} W m^{-2}) levels and of inferring physical properties (temperature and emission measure) from the MinXSS data alone. Moreover, coronal elemental abundances can be inferred, specifically for Fe, Ca, Si, Mg, S, Ar, and Ni, when the count rate is sufficiently high at each elemental spectral feature. Additionally, temperature response curves and emission measure loci demonstrate the MinXSS sensitivity to plasma emission at different temperatures. MinXSS observations coupled with those from other solar observatories can help address some of the most compelling questions in solar coronal physics. Finally, simultaneous observations by MinXSS and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) can provide the most spectrally complete soft X-ray solar flare photon flux measurements to date.

Ground Calibration of the Astro-H (Hitomi) Soft X-Ray Spectrometer

NASA Technical Reports Server (NTRS)

Eckart, M. E.; Adams, J. S.; Boyce, K. R.; Brown, G. V.; Chiao, Meng P.; Fujimoto, R. J.; Haas, D.; Den Herder, J. W.; Ishisaki, Y.; Kelley, R. L.;

Instrumentation '79.

ERIC Educational Resources Information Center

Chemical and Engineering News, 1979

1979-01-01

Surveys the state of commerical development of analytical instrumentation as reflected by the Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. Includes optical spectroscopy, liquid chromatography, magnetic spectrometers, and x-ray. (Author/MA)

History of Chandra X-Ray Observatory

NASA Image and Video Library

1997-04-15

This photograph captures the installation of the Chandra X-Ray Observatory, formerly Advanced X-Ray Astrophysics Facility (AXAF), Advanced Charged-Coupled Device (CCD) Imaging Spectrometer (ACIS) into the Vacuum Chamber at the X-Ray Calibration Facility (XRCF) at Marshall Space Flight Center (MSFC). The AXAF was renamed Chandra X-Ray Observatory (CXO) in 1999. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It observes x-rays from high-energy regions of the universe, such as hot gas in the remnants of exploded stars. The ACIS is one of two focal plane instruments. As the name suggests, this instrument is an array of CCDs similar to those used in a camcorder. This instrument will be especially useful because it can make x-ray images and measure the energies of incoming x-rays. It is the instrument of choice for studying the temperature variation across x-ray sources, such as vast clouds of hot-gas intergalactic space. MSFC's XRCF is the world's largest, most advanced laboratory for simulating x-ray emissions from distant celestial objects. It produces a space-like environment in which components related to x-ray telescope imaging are tested and the quality of their performances in space is predicted. TRW, Inc. was the prime contractor for the development of the CXO and NASA's MSFC was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The CXO was launched July 22, 1999 aboard the Space Shuttle Columbia (STS-93).

A compact dispersive refocusing Rowland circle X-ray emission spectrometer for laboratory, synchrotron, and XFEL applications

DOE PAGES

Holden, William M.; Hoidn, Oliver R.; Ditter, Alexander S.; ...

2017-07-27

X-ray emission spectroscopy is emerging as an important complement to x-ray absorption fine structure spectroscopy, providing a characterization of the occupied electronic density of states local to the species of interest. Here, we present details of the design and performance of a compact x-ray emission spectrometer that uses a dispersive refocusing Rowland (DRR) circle geometry to achieve excellent performance for the 2-2.5 keV range, i.e., especially for the K-edge emission from sulfur and phosphorous. The DRR approach allows high energy resolution even for unfocused x-ray sources. This property enables high count rates in laboratory studies, approaching those of insertion-device beamlinesmore » at third-generation synchrotrons, despite use of only a low-powered, conventional x-ray tube. The spectrometer, whose overall scale is set by use of a 10-cm diameter Rowland circle and a new small-pixel complementary metal-oxide-semiconductor x-ray camera, is easily portable to synchrotron or x-ray free electron laser beamlines. Photometrics from measurements at the Advanced Light Source show excellent overall instrumental efficiency. In addition, the compact size of this instrument lends itself to future multiplexing to gain large factors in net collection efficiency or its implementation in controlled gas gloveboxes either in the lab or in an endstation.« less

Near-edge x-ray absorption fine structure spectroscopy at atmospheric pressure with a table-top laser-induced soft x-ray source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kühl, Frank-Christian, E-mail: Frank-christian.kuehl@mail.de; Müller, Matthias, E-mail: matthias.mueller@llg-ev.de; Schellhorn, Meike

2016-07-15

The authors present a table-top soft x-ray absorption spectrometer, accomplishing investigations of the near-edge x-ray absorption fine structure (NEXAFS) in a laboratory environment. The system is based on a low debris plasma ignited by a picosecond laser in a pulsed krypton gas jet, emitting soft x-ray radiation in the range from 1 to 5 nm. For absorption spectroscopy in and around the “water window” (2.3–4.4 nm), a compact helium purged sample compartment for experiments at atmospheric pressure has been constructed and tested. NEXAFS measurements on CaCl{sub 2} and KMnO{sub 4} samples were conducted at the calcium and manganese L-edges, as well asmore » at the oxygen K-edge in air, atmospheric helium, and under vacuum, respectively. The results indicate the importance of atmospheric conditions for an investigation of sample hydration processes.« less

Confocal depth-resolved fluorescence micro-X-ray absorption spectroscopy for the study of cultural heritage materials: a new mobile endstation at the Beijing Synchrotron Radiation Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Guang; Chu, Shengqi; Sun, Tianxi

A confocal fluorescence endstation for depth-resolved micro-X-ray absorption spectroscopy is described. A polycapillary half-lens defines the incident beam path and a second polycapillary half-lens at 90° defines the probe sample volume. An automatic alignment program based on an evolutionary algorithm is employed to make the alignment procedure efficient. This depth-resolved system was examined on a general X-ray absorption spectroscopy (XAS) beamline at the Beijing Synchrotron Radiation Facility. Sacrificial red glaze (AD 1368–1644) china was studied to show the capability of the instrument. As a mobile endstation to be applied on multiple beamlines, the confocal system can improve the function andmore » flexibility of general XAS beamlines, and extend their capabilities to a wider user community.« less

An alpha particle instrument with alpha, proton, and X-ray modes for planetary chemical analyses

NASA Technical Reports Server (NTRS)

Economou, T. E.; Turkevich, A. L.

1976-01-01

The interaction of alpha particles with matter is employed in a compact instrument that could provide rather complete in-situ chemical analyses of surfaces and thin atmospheres of extraterrestrial bodies. The instrument is a miniaturized and improved version of the Surveyor lunar instrument. The backscattering of alpha particles and (alpha, p) reactions provide analytical data on the light elements (carbon-iron). An X-ray mode that detects the photons produced by the alpha sources provides sensitivity and resolution for the chemical elements heavier than about silicon. The X-rays are detected by semiconductor detectors having a resolution between 150 and 250 eV at 5.9 keV. Such an instrument can identify and determine with good accuracy 99 percent of the atoms (except hydrogen) in rocks. For many trace elements, the detecting sensitivity is a few ppm. Auxiliary sources could be used to enhance the sensitivities for elements of special interest. The instrument could probably withstand the acceleration involved in semi-hard landings.

Annealing induced atomic rearrangements on (Ga,In) (N,As) probed by hard X-ray photoelectron spectroscopy and X-ray absorption fine structure.

PubMed

Ishikawa, Fumitaro; Higashi, Kotaro; Fuyuno, Satoshi; Morifuji, Masato; Kondow, Masahiko; Trampert, Achim

2018-04-13

We study the effects of annealing on (Ga 0.64 ,In 0.36 ) (N 0.045 ,As 0.955 ) using hard X-ray photoelectron spectroscopy and X-ray absorption fine structure measurements. We observed surface oxidation and termination of the N-As bond defects caused by the annealing process. Specifically, we observed a characteristic chemical shift towards lower binding energies in the photoelectron spectra related to In. This phenomenon appears to be caused by the atomic arrangement, which produces increased In-N bond configurations within the matrix, as indicated by the X-ray absorption fine structure measurements. The reduction in the binding energies of group-III In, which occurs concomitantly with the atomic rearrangements of the matrix, causes the differences in the electronic properties of the system before and after annealing.

X-Ray Absorption near Edge Structure Spectroscopy of Nanodiamonds from the Allende Meteorite

NASA Technical Reports Server (NTRS)

Flynn, G. J.; Keller, L. P.; Hill, H.; Jacobsen, C.; Wirick, S.

2000-01-01

Carbon X-ray Absorption Near Edge Structure Spectroscopy shows Allende DM nanodiamonds have two pre-edge peaks, consistent with other small diamonds, but fail to show a diamond exciton which is seen in 3.6 nm diamond thin films.

Advanced X-ray Astrophysics Facility (AXAF) science instruments

NASA Technical Reports Server (NTRS)

Winkler, Carl E.; Dailey, Carroll C.; Cumings, Nesbitt P.

1991-01-01

The overall AXAF program is summarized, with particular emphasis given to its science instruments. The science objectives established for AXAF are to determine the nature of celestial objects, from normal stars to quasars, to elucidate the nature of the physical processes which take place in and between astronomical objects, and to shed light on the history and evolution of the universe. Attention is given to the AXAF CCD imaging spectrometer, which is to provide spectrally and temporally resolved imaging, or, in conjunction with transmission grating, high-resolution dispersed spectral images of celestial sources. A high-resolution camera, an X-ray spectrometer, and the Bragg Crystal Spectrometer are also discussed.

High-sensitivity ESCA instrument

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davies, R.D.; Herglotz, H.K.; Lee, J.D.

1973-01-01

A new electron spectroscopy for chemical analysis (ESCA) instrument has been developed to provide high sensitivity and efficient operation for laboratory analysis of composition and chemical bonding in very thin surface layers of solid samples. High sensitivity is achieved by means of the high-intensity, efficient x-ray source described by Davies and Herglotz at the 1968 Denver X-Ray Conference, in combination with the new electron energy analyzer described by Lee at the 1972 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. A sample chamber designed to provide for rapid introduction and replacement of samples has adequate facilities for various sample treatmentsmore » and conditiouing followed immediately by ESCA analysis of the sample. Examples of application are presented, demonstrating the sensitivity and resolution achievable with this instrument. Its usefulness in trace surface analysis is shown and some chemical shifts'' measured by the instrument are compared with those obtained by x-ray spectroscopy. (auth)« less

Optical Metrology for the Segmented Optics on the Constellation-X Spectroscopy X-Ray Telescope

NASA Technical Reports Server (NTRS)

Content, David; Colella, David; Fleetwood, Charles; Hadjimichael, Theo; Lehan, John; McMann, Joseph; Reid, Paul; Saha, Timo; Wright, Geraldine; Zhang, William

2004-01-01

We present the metrology requirements and metrology implementation necessary to prove out the reflector technology for the Constellation X(C-X) spectroscopy X-ray telescope (SXT). This segmented, 1.6m diameter highly nested Wolter-1 telescope presents many metrology and alignment challenges. In particular, these mirrors have a stringent imaging error budget as compared to their intrinsic stiffness; This is required for Constellation-X to have sufficient effective area with the weight requirement. This has implications for the metrology that can be used. A variety of contract and noncontact optical profiling and interferometric methods are combined to test the formed glass substrates before replication and the replicated reflector segments.The reflectors are tested both stand-alone and in-situ in an alignment tower.Some of these methods have not been used on prior X-ray telescopes and some are feasible only because of the segmented approach used on the SXT. Methods discussed include high precision coordinate measurement machines using very low force or optical probe axial interferometric profiling azimuthal circularity profiling and use of advanced null optics such as conical computer generated hologram (CGHs).

Thermal design and performance of the REgolith x-ray imaging spectrometer (REXIS) instrument

NASA Astrophysics Data System (ADS)

Stout, Kevin D.; Masterson, Rebecca A.

2014-08-01

The REgolith X-ray Imaging Spectrometer (REXIS) instrument is a student collaboration instrument on the OSIRIS-REx asteroid sample return mission scheduled for launch in September 2016. The REXIS science mission is to characterize the elemental abundances of the asteroid Bennu on a global scale and to search for regions of enhanced elemental abundance. The thermal design of the REXIS instrument is challenging due to both the science requirements and the thermal environment in which it will operate. The REXIS instrument consists of two assemblies: the spectrometer and the solar X-ray monitor (SXM). The spectrometer houses a 2x2 array of back illuminated CCDs that are protected from the radiation environment by a one-time deployable cover and a collimator assembly with coded aperture mask. Cooling the CCDs during operation is the driving thermal design challenge on the spectrometer. The CCDs operate in the vicinity of the electronics box, but a 130 °C thermal gradient is required between the two components to cool the CCDs to -60 °C in order to reduce noise and obtain science data. This large thermal gradient is achieved passively through the use of a copper thermal strap, a large radiator facing deep space, and a two-stage thermal isolation layer between the electronics box and the DAM. The SXM is mechanically mounted to the sun-facing side of the spacecraft separately from the spectrometer and characterizes the highly variable solar X-ray spectrum to properly interpret the data from the asteroid. The driving thermal design challenge on the SXM is cooling the silicon drift detector (SDD) to below -30 °C when operating. A two-stage thermoelectric cooler (TEC) is located directly beneath the detector to provide active cooling, and spacecraft MLI blankets cover all of the SXM except the detector aperture to radiatively decouple the SXM from the flight thermal environment. This paper describes the REXIS thermal system requirements, thermal design, and analyses, with

X-ray Spectrometry.

ERIC Educational Resources Information Center

Markowicz, Andrzej A.; Van Grieken, Rene E.

1984-01-01

Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

X-ray Emission Spectroscopy of Biomimetic Mn Coordination Complexes.

PubMed

Jensen, Scott C; Davis, Katherine M; Sullivan, Brendan; Hartzler, Daniel A; Seidler, Gerald T; Casa, Diego M; Kasman, Elina; Colmer, Hannah E; Massie, Allyssa A; Jackson, Timothy A; Pushkar, Yulia

2017-06-15

Understanding the function of Mn ions in biological and chemical redox catalysis requires precise knowledge of their electronic structure. X-ray emission spectroscopy (XES) is an emerging technique with a growing application to biological and biomimetic systems. Here, we report an improved, cost-effective spectrometer used to analyze two biomimetic coordination compounds, [Mn IV (OH) 2 (Me 2 EBC)] 2+ and [Mn IV (O)(OH)(Me 2 EBC)] + , the second of which contains a key Mn IV ═O structural fragment. Despite having the same formal oxidation state (Mn IV ) and tetradentate ligands, XES spectra from these two compounds demonstrate different electronic structures. Experimental measurements and DFT calculations yield different localized spin densities for the two complexes resulting from Mn IV -OH conversion to Mn IV ═O. The relevance of the observed spectroscopic changes is discussed for applications in analyzing complex biological systems such as photosystem II. A model of the S 3 intermediate state of photosystem II containing a Mn IV ═O fragment is compared to recent time-resolved X-ray diffraction data of the same state.

Clocking Femtosecond Collisional Dynamics via Resonant X-Ray Spectroscopy

DOE PAGES

van den Berg, Q. Y.; Fernandez-Tello, E. V.; Burian, T.; ...

2018-02-01

Electron-ion collisional dynamics is of fundamental importance in determining plasma transport properties, nonequilibrium plasma evolution, and electron damage in diffraction imaging applications using bright x-ray free-electron lasers (FELs). Here in this paper, we describe the first experimental measurements of ultrafast electron impact collisional ionization dynamics using resonant core-hole spectroscopy in a solid-density magnesium plasma, created and diagnosed with the Linac Coherent Light Source x-ray FEL. By resonantly pumping the 1s → 2p transition in highly charged ions within an optically thin plasma, we have measured how off-resonance charge states are populated via collisional processes on femtosecond time scales. We presentmore » a collisional cross section model that matches our results and demonstrates how the cross sections are enhanced by dense-plasma effects including continuum lowering. Nonlocal thermodynamic equilibrium collisional radiative simulations show excellent agreement with the experimental results and provide new insight on collisional ionization and three-body-recombination processes in the dense-plasma regime.« less

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

X-ray absorption spectroscopy investigations on oxidized Ni/Au contacts to p-GaN.

PubMed

Jan, J C; Asokan, K; Chiou, J W; Pong, W F; Tseng, P K; Chen, L C; Chen, F R; Lee, J F; Wu, J S; Lin, H J; Chen, C T

2001-03-01

X-ray absorption spectroscopy was used to investigate the electronic structure of as-deposited and oxidized Ni/Au contacts to p-GaN and to elucidate the mechanism responsible for low impedance. X-ray absorption near edge spectra of Ni K- and L3,2-edges clearly indicate formation of NiO on the sample surface after annealing. The reason for low impedance may be attributed to increase in hole concentration and existence of p-NiO layer on the surface.

CubeX: The CubeSAT X-ray Telescope for Elemental Abundance Mapping of Airless Bodies and X-ray Pulsar Navigation

NASA Astrophysics Data System (ADS)

Nittler, L. R.; Hong, J.; Kenter, A.; Romaine, S.; Allen, B.; Kraft, R.; Masterson, R.; Elvis, M.; Gendreau, K.; Crawford, I.; Binzel, R.; Boynton, W. V.; Grindlay, J.; Ramsey, B.

2017-12-01

The surface elemental composition of a planetary body provides crucial information about its origin, geological evolution, and surface processing, all of which can in turn provide information about solar system evolution as a whole. Remote sensing X-ray fluorescence (XRF) spectroscopy has been used successfully to probe the major-element compositions of airless bodies in the inner solar system, including the Moon, near-Earth asteroids, and Mercury. The CubeSAT X-ray Telescope (CubeX) is a concept for a 6U planetary X-ray telescope (36U with S/C), which utilizes Miniature Wolter-I X-ray optics (MiXO), monolithic CMOS and SDD X-ray sensors for the focal plane, and a Solar X-ray Monitor (heritage from the REXIS XRF instrument on NASA's OSIRIS-REx mission). CubeX will map the surface elemental composition of diverse airless bodies by spectral measurement of XRF excited by solar X-rays. The lightweight ( 1 kg) MiXO optics provide sub-arcminute resolution with low background, while the inherently rad-hard CMOS detectors provide improved spectral resolution ( 150 eV) at 0 °C. CubeX will also demonstrate X-ray pulsar timing based deep space navigation (XNAV). Successful XNAV will enable autonomous deep navigation with little to no support from the Deep Space Network, hence lowering the operation cost for many more planetary missions. Recently selected by NASA Planetary Science Deep Space SmallSat Studies, the first CubeX concept, designed to rideshare to the Moon as a secondary spacecraft on a primary mission, is under study in collaboration with the Mission Design Center at NASA Ames Research Center. From high altitude ( 6,000 km) frozen polar circular orbits, CubeX will study > 8 regions ( 110 km) of geological interest on the Moon over one year to produce a high resolution ( 2-3 km) elemental abundance map of each region. The novel focal plane design of CubeX also allows us to evaluate the performance of absolute navigation by sequential observations of several

Flares from small to large: X-ray spectroscopy of Proxima Centauri with XMM-Newton

NASA Astrophysics Data System (ADS)

Güdel, M.; Audard, M.; Reale, F.; Skinner, S. L.; Linsky, J. L.

2004-03-01

We report results from a comprehensive study of the nearby M dwarf Proxima Centauri with the XMM-Newton satellite, using simultaneously its X-ray detectors and the Optical Monitor with its U band filter. We find strongly variable coronal X-ray emission, with flares ranging over a factor of 100 in peak flux. The low-level emission is found to be continuously variable on at least three time scales (a slow decay of several hours, modulation on a time scale of 1 hr, and weak flares with time scales of a few minutes). Several weak flares are characteristically preceded by an optical burst, compatible with predictions from standard solar flare models. We propose that the U band bursts are proxies for the elusive stellar non-thermal hard X-ray bursts suggested from solar observations. In the course of the observation, a very large X-ray flare started and was observed essentially in its entirety. Its peak luminosity reached 3.9× 1028 erg s-1 [0.15-10 keV], and the total X-ray energy released in the same band is derived to be 1.5× 1032 ergs. This flare has for the first time allowed to measure significant density variations across several phases of the flare from X-ray spectroscopy of the O VII He-like triplet; we find peak densities reaching up to 4× 1011 cm-3 for plasma of about 1-5 MK. Abundance ratios show little variability in time, with a tendency of elements with a high first ionization potential to be overabundant relative to solar photospheric values. Using Fe XVII lines with different oscillator strengths, we do not find significant effects due to opacity during the flare, indicating that large opacity increases are not the rule even in extreme flares. We model the large flare in terms of an analytic 2-Ribbon flare model and find that the flaring loop system should have large characteristic sizes (≈ 1R*) within the framework of this simplistic model. These results are supported by full hydrodynamic simulations. Comparing the large flare to flares of similar

Diagnosis of a two wire X-pinch by X-ray absorption spectroscopy utilizing a doubly curved ellipsoidal crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cahill, A. D., E-mail: adc87@cornell.edu; Hoyt, C. L., E-mail: adc87@cornell.edu; Shelkovenko, T. A., E-mail: adc87@cornell.edu

2014-12-15

X-ray absorption spectroscopy is a powerful tool for the diagnosis of plasmas over a wide range of both temperature and density. However, such a measurement is often limited to probing plasmas with temperatures well below that of the x-ray source in order to avoid object plasma emission lines from obscuring important features of the absorption spectrum. This has excluded many plasmas from being investigated by this technique. We have developed an x-ray spectrometer that provides the ability to record absorption spectra from higher temperature plasmas than the usual approach allows without the risk of data contamination by line radiation emittedmore » by the plasma under study. This is accomplished using a doubly curved mica crystal which is bent both elliptically and cylindrically. We present here initial absorption spectra obtained from an aluminum x-pinch plasma.« less

Bulk sensitive hard x-ray photoemission electron microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patt, M., E-mail: m.patt@fz-juelich.de; Wiemann, C.; Weber, N.

Hard x-ray photoelectron spectroscopy (HAXPES) has now matured into a well-established technique as a bulk sensitive probe of the electronic structure due to the larger escape depth of the highly energetic electrons. In order to enable HAXPES studies with high lateral resolution, we have set up a dedicated energy-filtered hard x-ray photoemission electron microscope (HAXPEEM) working with electron kinetic energies up to 10 keV. It is based on the NanoESCA design and also preserves the performance of the instrument in the low and medium energy range. In this way, spectromicroscopy can be performed from threshold to hard x-ray photoemission. Themore » high potential of the HAXPEEM approach for the investigation of buried layers and structures has been shown already on a layered and structured SrTiO{sub 3} sample. Here, we present results of experiments with test structures to elaborate the imaging and spectroscopic performance of the instrument and show the capabilities of the method to image bulk properties. Additionally, we introduce a method to determine the effective attenuation length of photoelectrons in a direct photoemission experiment.« less

X-ray scattering and spectroscopy studies on diesel soot from oxygenated fuel under various engine load conditions

USGS Publications Warehouse

Braun, Andreas; Shah, N.; Huggins, Frank E.; Kelly, K.E.; Sarofim, A.; Jacobsen, C.; Wirick, S.; Francis, H.; Ilavsky, J.; Thomas, G.E.; Huffman, G.P.

2005-01-01

Diesel soot from reference diesel fuel and oxygenated fuel under idle and load engine conditions was investigated with X-ray scattering and X-ray carbon K-edge absorption spectroscopy. Up to five characteristic size ranges were found. Idle soot was generally found to have larger primary particles and aggregates but smaller crystallites, than load soot. Load soot has a higher degree of crystallinity than idle soot. Adding oxygenates to diesel fuel enhanced differences in the characteristics of diesel soot, or even reversed them. Aromaticity of idle soot from oxygenated diesel fuel was significantly larger than from the corresponding load soot. Carbon near-edge X-ray absorption fine structure (NEXAFS) spectroscopy was applied to gather information about the presence of relative amounts of carbon double bonds (CC, CO) and carbon single bonds (C-H, C-OH, COOH). Using scanning X-ray transmission microspectroscopy (STXM), the relative amounts of these carbon bond states were shown to vary spatially over distances approximately 50 to 100 nm. The results from the X-ray techniques are supported by thermo-gravimetry analysis and high-resolution transmission electron microscopy. ?? 2005 Elsevier Ltd. All rights reserved.

Revealing hole trapping in zinc oxide nanoparticles by time-resolved X-ray spectroscopy

DOE PAGES

Penfold, Thomas J.; Szlachetko, Jakub; Santomauro, Fabio G.; ...

2018-02-02

Nanostructures of transition metal oxides (TMO), such as ZnO, have attracted considerable interest for solar-energy conversion and photocatalysis. For the latter, trapping of charge carriers has an essential role. The probing of electron trapping in the conduction band of room temperature photoexcited TMOs has recently become possible owing to the emergence of time-resolved element-sensitive methods, such as X-ray spectroscopy. However, because the valence band of TMOs is dominated by the oxygen 2p orbitals,holes have so far escaped observation. Herein we use a novel dispersive X-ray emission spectrometer combined with X-ray absorption spectroscopy to directly probe the charge carrier relaxation andmore » trapping pro-cesses in ZnO nanoparticles after above band-gap photoexcitation. Here, our results, supported by simulations, demonstrate that within our temporal resolution of 80 ps, photo-excited holes are trapped at singly charged oxygen vacancies, turning them into doubly charged vacancies, which causes an outward displacement by approximately 15% of the four surrounding Zn atoms away from the central vacancy. These traps recombine radiatively with the delocalised electrons of the conduction band yielding the commonly observed green luminescence. This identification of the hole traps and their evolution provides new insight for future developments of TMO-based nanodevices.« less

Revealing hole trapping in zinc oxide nanoparticles by time-resolved X-ray spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penfold, Thomas J.; Szlachetko, Jakub; Santomauro, Fabio G.

Nanostructures of transition metal oxides (TMO), such as ZnO, have attracted considerable interest for solar-energy conversion and photocatalysis. For the latter, trapping of charge carriers has an essential role. The probing of electron trapping in the conduction band of room temperature photoexcited TMOs has recently become possible owing to the emergence of time-resolved element-sensitive methods, such as X-ray spectroscopy. However, because the valence band of TMOs is dominated by the oxygen 2p orbitals,holes have so far escaped observation. Herein we use a novel dispersive X-ray emission spectrometer combined with X-ray absorption spectroscopy to directly probe the charge carrier relaxation andmore » trapping pro-cesses in ZnO nanoparticles after above band-gap photoexcitation. Here, our results, supported by simulations, demonstrate that within our temporal resolution of 80 ps, photo-excited holes are trapped at singly charged oxygen vacancies, turning them into doubly charged vacancies, which causes an outward displacement by approximately 15% of the four surrounding Zn atoms away from the central vacancy. These traps recombine radiatively with the delocalised electrons of the conduction band yielding the commonly observed green luminescence. This identification of the hole traps and their evolution provides new insight for future developments of TMO-based nanodevices.« less

New Optimizations of Microcalorimeter Arrays for High-Resolution Imaging X-ray Spectroscopy

NASA Astrophysics Data System (ADS)

Kilbourne, Caroline

We propose to continue our successful research program in developing arrays of superconducting transition-edge sensors (TES) for x-ray astrophysics. Our standard 0.3 mm TES pixel achieves better than 2.5-eV resolution, and we now make 32x32 arrays of such pixels. We have also achieved better than 1-eV resolution in smaller pixels, and promising performance in a range of position-sensitive designs. We propose to continue to advance the designs of both the single-pixel and position-sensitive microcalorimeters so that we can produce arrays suitable for several x-ray spectroscopy observatories presently in formulation. We will also investigate various array and pixel optimizations such as would be needed for large arrays for surveys, large- pixel arrays for diffuse soft x-ray measurements, or sub-arrays of fast pixels optimized for neutron-star burst spectroscopy. In addition, we will develop fabrication processes for integrating sub-arrays with very different pixel designs into a monolithic focal-plane array to simplify the design of the focal-plane assembly and make feasible new detector configurations such as the one currently baselined for AXSIO. Through a series of measurements on test devices, we have improved our understanding of the weak-link physics governing the observed resistive transitions in TES detectors. We propose to build on that work and ultimately use the results to improve the immunity of the detector to environmental magnetic fields, as well as its fundamental performance, in each of the targeted optimizations we are developing.

Design of MiSolFA Hard X-Ray Imager

NASA Astrophysics Data System (ADS)

Lastufka, Erica; Casadei, Diego

2017-08-01

Advances in the study of coronal electron-accelerating regions have so far been limited by the dynamic range of X-ray instruments. A quick and economical alternative to desirable focusing optics technology is stereo observation. The micro-satellite MiSolFA (Micro Solar-Flare Apparatus) is designed both as a stand-alone X-ray imaging spectrometer and a complement to the Spectrometer/Telescope for Imaging X-rays (STIX) mission. These instruments will be the first pair of cross-calibrated X-ray imaging spectrometers to look at solar flares from very different points of view. MiSolFA will achieve indirect imaging between 10 and 60 keV and provide spectroscopy up to 100 keV, equipped with grids producing moiré patterns in a similar way to STIX. New manufacturing techniques produce gold gratings on a graphite or silicon substrate, with periods ranging from 15 to 225 micrometers, separated by a distance of 15.47 cm, to achieve a spatial resolutions from 10" to 60" (as compared to RHESSI's separation of 150 cm and 1" resolution). We present the progress of the imager design, the performance of the first prototypes, and reach out to the community for further scientific objectives to consider in optimizing the final design.

A high-resolving-power x-ray spectrometer for the OMEGA EP Laser (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nilson, P. M., E-mail: pnil@lle.rochester.edu; Ehrne, F.; Mileham, C.

A high-resolving-power x-ray spectrometer has been developed for the OMEGA EP Laser System based on a spherically bent Si [220] crystal with a radius of curvature of 330 mm and a Spectral Instruments (SI) 800 Series charge-coupled device. The instrument measures time-integrated x-ray emission spectra in the 7.97- to 8.11-keV range, centered on the Cu K{sub α1} line. To demonstrate the performance of the spectrometer under high-power conditions, K{sub α1,2} emission spectra were measured from Cu foils irradiated by the OMEGA EP laser with 100-J, 1-ps pulses at focused intensities above 10{sup 18} W/cm{sup 2}. The ultimate goal is tomore » couple the spectrometer to a picosecond x-ray streak camera and measure temperature-equilibration dynamics inside rapidly heated materials. The plan for these ultrafast streaked x-ray spectroscopy studies is discussed.« less

In situ/Operando studies of electrocatalysts using hard X-ray spectroscopy

DOE PAGES

Lassalle-Kaiser, Benedikt; Gul, Sheraz; Kern, Jan; ...

2017-05-02

This review focuses on the use of X-ray absorption and emission spectroscopy techniques using hard X-rays to study electrocatalysts under in situ/operando conditions. The importance and the versatility of methods in the study of electrodes in contact with the electrolytes are described, when they are being cycled through the catalytic potentials during the progress of the oxygen-evolution, oxygen reduction and hydrogen evolution reactions. The catalytic oxygen evolution reaction is illustrated with examples using three oxides, Co, Ni and Mn, and two sulfides, Mo and Co. These are used as examples for the hydrogen evolution reaction. A bimetallic, bifunctional oxygen evolvingmore » and oxygen reducing Ni/Mn oxide is also presented. The various advantages and constraints in the use of these techniques and the future outlook are discussed.« less

Deciphering the Complex Chemistry of Deep-Ocean Particles Using Complementary Synchrotron X-ray Microscope and Microprobe Instruments.

PubMed

Toner, Brandy M; German, Christopher R; Dick, Gregory J; Breier, John A

2016-01-19

The reactivity and mobility of natural particles in aquatic systems have wide ranging implications for the functioning of Earth surface systems. Particles in the ocean are biologically and chemically reactive, mobile, and complex in composition. The chemical composition of marine particles is thought to be central to understanding processes that convert globally relevant elements, such as C and Fe, among forms with varying bioavailability and mobility in the ocean. The analytical tools needed to measure the complex chemistry of natural particles are the subject of this Account. We describe how a suite of complementary synchrotron radiation instruments with nano- and micrometer focusing, and X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) capabilities are changing our understanding of deep-ocean chemistry and life. Submarine venting along mid-ocean ridges creates hydrothermal plumes where dynamic particle-forming reactions occur as vent fluids mix with deep-ocean waters. Whether plumes are net sources or sinks of elements in ocean budgets depends in large part on particle formation, reactivity, and transport properties. Hydrothermal plume particles have been shown to host microbial communities and exhibit complex size distributions, aggregation behavior, and composition. X-ray microscope and microprobe instruments can address particle size and aggregation, but their true strength is in measuring chemical composition. Plume particles comprise a stunning array of inorganic and organic phases, from single-crystal sulfides to poorly ordered nanophases and polymeric organic matrices to microbial cells. X-ray microscopes and X-ray microprobes with elemental imaging, XAS, and XRD capabilities are ideal for investigating these complex materials because they can (1) measure the chemistry of organic and inorganic constituents in complex matrices, usually within the same particle or aggregate, (2) provide strong signal-to-noise data with exceedingly small

Simultaneous Femtosecond X-ray Spectroscopy and Diffraction of Photosystem II at Room Temperature

PubMed Central

Kern, Jan; Alonso-Mori, Roberto; Tran, Rosalie; Hattne, Johan; Gildea, Richard J.; Echols, Nathaniel; Glöckner, Carina; Hellmich, Julia; Laksmono, Hartawan; Sierra, Raymond G.; Lassalle-Kaiser, Benedikt; Koroidov, Sergey; Lampe, Alyssa; Han, Guangye; Gul, Sheraz; DiFiore, Dörte; Milathianaki, Despina; Fry, Alan R.; Miahnahri, Alan; Schafer, Donald W.; Messerschmidt, Marc; Seibert, M. Marvin; Koglin, Jason E.; Sokaras, Dimosthenis; Weng, Tsu-Chien; Sellberg, Jonas; Latimer, Matthew J.; Grosse-Kunstleve, Ralf W.; Zwart, Petrus H.; White, William E.; Glatzel, Pieter; Adams, Paul D.; Bogan, Michael J.; Williams, Garth J.; Boutet, Sébastien; Messinger, Johannes; Zouni, Athina; Sauter, Nicholas K.; Yachandra, Vittal K.; Bergmann, Uwe; Yano, Junko

2013-01-01

Intense femtosecond X-ray pulses produced at the Linac Coherent Light Source (LCLS) were used for simultaneous X-ray diffraction (XRD) and X-ray emission spectroscopy (XES) of microcrystals of Photosystem II (PS II) at room temperature. This method probes the overall protein structure and the electronic structure of the Mn4CaO5 cluster in the oxygen-evolving complex of PS II. XRD data are presented from both the dark state (S1) and the first illuminated state (S2) of PS II. Our simultaneous XRD/XES study shows that the PS II crystals are intact during our measurements at the LCLS, not only with respect to the structure of PS II, but also with regard to the electronic structure of the highly radiation sensitive Mn4CaO5 cluster, opening new directions for future dynamics studies. PMID:23413188

Simultaneous femtosecond X-ray spectroscopy and diffraction of photosystem II at room temperature.

PubMed

Kern, Jan; Alonso-Mori, Roberto; Tran, Rosalie; Hattne, Johan; Gildea, Richard J; Echols, Nathaniel; Glöckner, Carina; Hellmich, Julia; Laksmono, Hartawan; Sierra, Raymond G; Lassalle-Kaiser, Benedikt; Koroidov, Sergey; Lampe, Alyssa; Han, Guangye; Gul, Sheraz; Difiore, Dörte; Milathianaki, Despina; Fry, Alan R; Miahnahri, Alan; Schafer, Donald W; Messerschmidt, Marc; Seibert, M Marvin; Koglin, Jason E; Sokaras, Dimosthenis; Weng, Tsu-Chien; Sellberg, Jonas; Latimer, Matthew J; Grosse-Kunstleve, Ralf W; Zwart, Petrus H; White, William E; Glatzel, Pieter; Adams, Paul D; Bogan, Michael J; Williams, Garth J; Boutet, Sébastien; Messinger, Johannes; Zouni, Athina; Sauter, Nicholas K; Yachandra, Vittal K; Bergmann, Uwe; Yano, Junko

2013-04-26

Intense femtosecond x-ray pulses produced at the Linac Coherent Light Source (LCLS) were used for simultaneous x-ray diffraction (XRD) and x-ray emission spectroscopy (XES) of microcrystals of photosystem II (PS II) at room temperature. This method probes the overall protein structure and the electronic structure of the Mn4CaO5 cluster in the oxygen-evolving complex of PS II. XRD data are presented from both the dark state (S1) and the first illuminated state (S2) of PS II. Our simultaneous XRD-XES study shows that the PS II crystals are intact during our measurements at the LCLS, not only with respect to the structure of PS II, but also with regard to the electronic structure of the highly radiation-sensitive Mn4CaO5 cluster, opening new directions for future dynamics studies.

Component analyses of urinary nanocrystallites of uric acid stone formers by combination of high-resolution transmission electron microscopy, fast Fourier transformation, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy.

PubMed

Sun, Xin-Yuan; Xue, Jun-Fa; Xia, Zhi-Yue; Ouyang, Jian-Ming

2015-06-01

This study aimed to analyse the components of nanocrystallites in urines of patients with uric acid (UA) stones. X-ray diffraction (XRD), Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy (HRTEM), fast Fourier transformation (FFT) of HRTEM, and energy dispersive X-ray spectroscopy (EDS) were performed to analyse the components of these nanocrystallites. XRD and FFT showed that the main component of urinary nanocrystallites was UA, which contains a small amount of calcium oxalate monohydrate and phosphates. EDS showed the characteristic absorption peaks of C, O, Ca and P. The formation of UA stones was closely related to a large number of UA nanocrystallites in urine. A combination of HRTEM, FFT, EDS and XRD analyses could be performed accurately to analyse the components of urinary nanocrystallites.

X-ray diagnostics of massive star winds

NASA Astrophysics Data System (ADS)

Oskinova, L. M.; Ignace, R.; Huenemoerder, D. P.

2017-11-01

Observations with powerful X-ray telescopes, such as XMM-Newton and Chandra, significantly advance our understanding of massive stars. Nearly all early-type stars are X-ray sources. Studies of their X-ray emission provide important diagnostics of stellar winds. High-resolution X-ray spectra of O-type stars are well explained when stellar wind clumping is taking into account, providing further support to a modern picture of stellar winds as non-stationary, inhomogeneous outflows. X-ray variability is detected from such winds, on time scales likely associated with stellar rotation. High-resolution X-ray spectroscopy indicates that the winds of late O-type stars are predominantly in a hot phase. Consequently, X-rays provide the best observational window to study these winds. X-ray spectroscopy of evolved, Wolf-Rayet type, stars allows to probe their powerful metal enhanced winds, while the mechanisms responsible for the X-ray emission of these stars are not yet understood.

Discovery of Spatial and Spectral Structure in the X-Ray Emission from the Crab Nebula

NASA Technical Reports Server (NTRS)

Weisskopf, Martin C.; Hester, J. Jeff; Tennant, Allyn F.; Elsner, Ronald F.; Schulz, Norbert S.; Marshall, Herman L.; Karovska, Margarita; Nichols, Joy S.; Swartz, Douglas A.; Kolodziejczak, Jeffery J.

2000-01-01

The Chandra X-Ray Observatory observed the Crab Nebula and pulsar during orbital calibration. Zeroth-order images with the High-Energy Transmission Grating (HETG) readout by the Advanced Charge Coupled Devices (CCD) Imaging Spectrometer spectroscopy array (ACIS-S) show a striking richness of X-ray structure at a resolution comparable to that of the best ground-based visible-light observations. The HETG-ACIS-S images reveal, for the first time, an X-ray inner ring within the X-ray torus, the suggestion of a hollow-tube structure for the torus, and X-ray knots along the inner ring and (perhaps) along the inward extension of the X-ray jet. Although complicated by instrumental effects and the brightness of the Crab Nebula, the spectrometric analysis shows systematic variations of the X-ray spectrum throughout the nebula.

Discovery of Spatial and Spectral Structure in the X-Ray Emission from the Crab Nebula.

PubMed

Weisskopf; Hester; Tennant; Elsner; Schulz; Marshall; Karovska; Nichols; Swartz; Kolodziejczak; O'Dell

2000-06-20

The Chandra X-Ray Observatory observed the Crab Nebula and pulsar during orbital calibration. Zeroth-order images with the High-Energy Transmission Grating (HETG) readout by the Advanced CCD Imaging Spectrometer spectroscopy array (ACIS-S) show a striking richness of X-ray structure at a resolution comparable to that of the best ground-based visible-light observations. The HETG-ACIS-S images reveal, for the first time, an X-ray inner ring within the X-ray torus, the suggestion of a hollow-tube structure for the torus, and X-ray knots along the inner ring and (perhaps) along the inward extension of the X-ray jet. Although complicated by instrumental effects and the brightness of the Crab Nebula, the spectrometric analysis shows systematic variations of the X-ray spectrum throughout the nebula.

Longterm lightcurves of X-ray binaries

NASA Astrophysics Data System (ADS)

Clarkson, William

The X-ray Binaries (XRB) consist of a compact object and a stellar companion, which undergoes large-scale mass-loss to the compact object by virtue of the tight ( P orb usually hours-days) orbit, producing an accretion disk surrounding the compact object. The liberation of gravitational potential energy powers exotic high-energy phenomena, indeed the resulting accretion/ outflow process is among the most efficient energy-conversion machines in the universe. The Burst And Transient Source Experiment (BATSE) and RXTE All Sky Monitor (ASM) have provided remarkable X-ray lightcurves above 1.3keV for the entire sky, at near-continuous coverage, for intervals of 9 and 7 years respectively (with ~3 years' overlap). With an order of magnitude increase in sensitivity compared to previous survey instruments, these instruments have provided new insight into the high-energy behaviour of XRBs on timescales of tens to thousands of binary orbits. This thesis describes detailed examination of the long-term X-ray lightcurves of the neutron star XRB X2127+119, SMC X-1, Her X- 1, LMC X-4, Cyg X-2 and the as yet unclassified Circinus X-1, and for Cir X-1, complementary observations in the IR band. Chapters 1 & 2 introduce X-ray Binaries in general and longterm periodicities in particular. Chapter 3 introduces the longterm datasets around which this work is based, and the chosen methods of analysis of these datasets. Chapter 4 examines the burst history of the XRB X2127+119, suggesting three possible interpretations of the apparently contradictory X-ray emission from this system, including a possible confusion of two spatially distinct sources (which was later vindicated by high-resolution imaging). Chapters 5 and 6 describe the characterisation of accretion disk warping, providing observational verification of the prevailing theoretical framework for such disk-warps. Chapters 7 & 8 examine the enigmatic XRB Circinus X-1 with high-resolution IR spectroscopy (chapter 7) and the RXTE

Discovery of Spatial and Spectral Structure in the X-Ray Emission from the Crab Nebula

NASA Technical Reports Server (NTRS)

Weisskopf, M.; Hester, J. J.; Tennant, A. F.; Elsner, R. F.; Schulz, N. S.; Marshall, H. L.; Karovska, M.; Nichols, J. S.; Swartz, D. A.; Kolodziejczak, J. J.

2000-01-01

The Chandra X-ray Observatory observed the Crab Nebula and Pulsar During orbital calibration. Zeroth-order images with the High-Energy Transmission Grating (HETG) read-out by the Advanced CCD Imaging Spectrometer spectroscopy array (ACIS-S) show a striking richness of X-ray structure, at a resolution comparable to that of the best ground-based visible-light observations. The HETG-ACIS-S images reveal, for the first time, an X-ray knots along the inner ring and (perhaps) along the inward extension of the X-ray jet. Although complicated by instrumental effects and the brightness of the Crab Nebula, the spectrometric analysis shows systematic variations of the X-ray spectrum throughout the Nebula.

Origin of Pressure-induced Superconducting Phase in K xFe 2-ySe 2 studied by Synchrotron X-ray Diffraction and Spectroscopy

DOE PAGES

Yamamoto, Yoshiya; Yamaoka, Hitoshi; Tanaka, Masashi; ...

2016-08-08

Pressure dependence of the electronic and crystal structures of K xFe 2–ySe 2, which has pressure-induced two superconducting domes of SC I and SC II, was investigated by x-ray emission spectroscopy and diffraction. X-ray diffraction data show that compressibility along the c-axis changes around 12 GPa, where a new superconducting phase of SC II appears. This suggests a possible tetragonal to collapsed tetragonal phase transition. X-ray emission spectroscopy data also shows the change in the electronic structure around 12 GPa. These results can be explained by the scenario that the two SC domes under pressure originate from the change ofmore » Fermi surface topology. Lastly, our results here show the pronounced increase of the density of states near the Fermi surface under pressure with a structural phase transition, which can help address our fundamental understanding for the appearance of the SC II phase.« less

High-rate x-ray spectroscopy in mammography with a CdTe detector: a digital pulse processing approach.

PubMed

Abbene, L; Gerardi, G; Principato, F; Del Sordo, S; Ienzi, R; Raso, G

2010-12-01

Direct measurement of mammographic x-ray spectra under clinical conditions is a difficult task due to the high fluence rate of the x-ray beams as well as the limits in the development of high resolution detection systems in a high counting rate environment. In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate x-ray spectroscopy in mammography. The DPP system performs a digital pile-up inspection and a digital pulse height analysis of the detector signals, digitized through a 14-bit, 100 MHz digitizer, for x-ray spectroscopy even at high photon counting rates. We investigated on the response of the digital detection system both at low (150 cps) and at high photon counting rates (up to 500 kcps) by using monoenergetic x-ray sources and a nonclinical molybdenum anode x-ray tube. Clinical molybdenum x-ray spectrum measurements were also performed by using a pinhole collimator and a custom alignment device. The detection system shows excellent performance up to 512 kcps with an energy resolution of 4.08% FWHM at 22.1 keV. Despite the high photon counting rate (up to 453 kcps), the molybdenum x-ray spectra, measured under clinical conditions, are characterized by a low number of pile-up events. The agreement between the attenuation curves and the half value layer values, obtained from the measured spectra, simulated spectra, and from the exposure values directly measured with an ionization chamber, also shows the accuracy of the measurements. These results make the proposed detection system a very attractive tool for both laboratory research and advanced quality controls in mammography.

X-ray photoelectron spectroscopy for characterization of wood surfaces in adhesion studies

Treesearch

James F. Beecher; Charles R. Frihart

2005-01-01

X-ray photoelectron spectroscopy (XPS) is one of a set of tools that have been used to characterize wood surfaces. Among the advantages of XPS are surface sensitivity, identification of nearly all elements, and frequently, discrimination of bonding states. For these reasons, XPS seemed to be an appropriate tool to help explain the differences in bond strength under wet...

Calibration sources and filters of the soft x-ray spectrometer instrument on the Hitomi spacecraft

NASA Astrophysics Data System (ADS)

de Vries, Cor P.; Haas, Daniel; Yamasaki, Noriko Y.; Herder, Jan-Willem den; Paltani, Stephane; Kilbourne, Caroline; Tsujimoto, Masahiro; Eckart, Megan E.; Leutenegger, Maurice A.; Costantini, Elisa; Dercksen, Johannes P. C.; Dubbeldam, Luc; Frericks, Martin; Laubert, Phillip P.; van Loon, Sander; Lowes, Paul; McCalden, Alec J.; Porter, Frederick S.; Ruijter, Jos; Wolfs, Rob

2018-01-01

The soft x-ray spectrometer was designed to operate onboard the Japanese Hitomi (ASTRO-H) satellite. In the beam of this instrument, there was a filter wheel containing x-ray filters and active calibration sources. This paper describes this filter wheel. We show the purpose of the filters and the preflight calibrations performed. In addition, we present the calibration source design and measured performance. Finally, we conclude with prospects for future missions.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butterworth, A.L.; Becker, N.; Gainsforth, Z.

2012-03-13

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 synchrotronmore » 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

Soft X-ray Focusing Telescope Aboard AstroSat: Design, Characteristics and Performance

NASA Astrophysics Data System (ADS)

Singh, K. P.; Stewart, G. C.; Westergaard, N. J.; Bhattacharayya, S.; Chandra, S.; Chitnis, V. R.; Dewangan, G. C.; Kothare, A. T.; Mirza, I. M.; Mukerjee, K.; Navalkar, V.; Shah, H.; Abbey, A. F.; Beardmore, A. P.; Kotak, S.; Kamble, N.; Vishwakarama, S.; Pathare, D. P.; Risbud, V. M.; Koyande, J. P.; Stevenson, T.; Bicknell, C.; Crawford, T.; Hansford, G.; Peters, G.; Sykes, J.; Agarwal, P.; Sebastian, M.; Rajarajan, A.; Nagesh, G.; Narendra, S.; Ramesh, M.; Rai, R.; Navalgund, K. H.; Sarma, K. S.; Pandiyan, R.; Subbarao, K.; Gupta, T.; Thakkar, N.; Singh, A. K.; Bajpai, A.

2017-06-01

The Soft X-ray focusing Telescope (SXT), India's first X-ray telescope based on the principle of grazing incidence, was launched aboard the AstroSat and made operational on October 26, 2015. X-rays in the energy band of 0.3-8.0 keV are focussed on to a cooled charge coupled device thus providing medium resolution X-ray spectroscopy of cosmic X-ray sources of various types. It is the most sensitive X-ray instrument aboard the AstroSat. In its first year of operation, SXT has been used to observe objects ranging from active stars, compact binaries, supernova remnants, active galactic nuclei and clusters of galaxies in order to study its performance and quantify its characteriztics. Here, we present an overview of its design, mechanical hardware, electronics, data modes, observational constraints, pipeline processing and its in-orbit performance based on preliminary results from its characterization during the performance verification phase.

Local Structure Determination of Carbon/Nickel Ferrite Composite Nanofibers Probed by X-ray Absorption Spectroscopy.

PubMed

Nilmoung, Sukunya; Kidkhunthod, Pinit; Maensiri, Santi

2015-11-01

Carbon/NiFe2O4 composite nanofibers have been successfully prepared by electrospinning method using a various concentration solution of Ni and Fe nitrates dispersed into polyacrylonitride (PAN) solution in N,N' dimethylformamide. The phase and mophology of PAN/NiFe2O4 composite samples were characterized and investigated by X-ray diffraction and scanning electron microscopy. The magnetic properties of the prepared samples were measured at ambient temperature by a vibrating sample magnetometer. It is found that all composite samples exhibit ferromagnetism. This could be local-structurally explained by the existed oxidation states of Ni2+ and Fe3+ in the samples. Moreover, local environments around Ni and Fe ions could be revealed by X-ray absorption spectroscopy (XAS) measurement including X-ray absorption near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS).

CONTIN XPCS: Software for Inverse Transform Analysis of X-Ray Photon Correlation Spectroscopy Dynamics

PubMed Central

Narayanan, Suresh; Zhang, Fan; Kuzmenko, Ivan; Ilavsky, Jan

2018-01-01

X-ray photon correlation spectroscopy (XPCS) and dynamic light scattering (DLS) both reveal dynamics using coherent scattering, but X-rays permit investigating of dynamics in a much more diverse array of materials. Heterogeneous dynamics occur in many such materials, and we showed how classic tools employed in analysis of heterogeneous DLS dynamics extend to XPCS, revealing additional information that conventional Kohlrausch exponential fitting obscures. This work presents the software implementation of inverse transform analysis of XPCS data called CONTIN XPCS, an extension of traditional CONTIN that accommodates dynamics encountered in equilibrium XPCS measurements. PMID:29875507

CONTIN XPCS: Software for Inverse Transform Analysis of X-Ray Photon Correlation Spectroscopy Dynamics.

PubMed

Andrews, Ross N; Narayanan, Suresh; Zhang, Fan; Kuzmenko, Ivan; Ilavsky, Jan

2018-02-01

X-ray photon correlation spectroscopy (XPCS) and dynamic light scattering (DLS) both reveal dynamics using coherent scattering, but X-rays permit investigating of dynamics in a much more diverse array of materials. Heterogeneous dynamics occur in many such materials, and we showed how classic tools employed in analysis of heterogeneous DLS dynamics extend to XPCS, revealing additional information that conventional Kohlrausch exponential fitting obscures. This work presents the software implementation of inverse transform analysis of XPCS data called CONTIN XPCS, an extension of traditional CONTIN that accommodates dynamics encountered in equilibrium XPCS measurements.

Differentiation of dental restorative materials combining energy-dispersive X-ray fluorescence spectroscopy and post-mortem CT.

PubMed

Merriam, Tim; Kaufmann, Rolf; Ebert, Lars; Figi, Renato; Erni, Rolf; Pauer, Robin; Sieberth, Till

2018-06-01

Today, post-mortem computed tomography (CT) is routinely used for forensic identification. Mobile energy-dispersive X-ray fluorescence (EDXRF) spectroscopy of a dentition is a method of identification that has the potential to be easier and cheaper than CT, although it cannot be used with every dentition. In challenging cases, combining both techniques could facilitate the process of identification and prove to be advantageous over chemical analyses. Nine dental restorative material brands were analyzed using EDXRF spectroscopy. Their differentiability was assessed by comparing each material's x-ray fluorescence spectrum and then comparing the spectra to previous research investigating differentiability in CT. To verify EDXRF's precision and accuracy, select dental specimens underwent comparative electron beam excited x-ray spectroscopy (EDS) scans, while the impact of the restorative surface area was studied by scanning a row of dental specimens with varying restorative surface areas (n = 10). EDXRF was able to differentiate all 36 possible pairs of dental filling materials; however, dual-energy CT was only able to differentiate 33 out of 36. The EDS scans showed correlating x-ray fluorescence peaks on the x-ray spectra compared to our EDXRF. In addition, the surface area showed no influence on the differentiability of the dental filling materials. EDXRF has the potential to facilitate corpse identification by differentiating and comparing restorative materials, providing more information compared to post-mortem CT alone. Despite not being able to explicitly identify a brand without a control sample or database, its fast and mobile use could accelerate daily routines or mass victim identification processes. To achieve this goal, further development of EDXRF scanners for this application and further studies evaluating the method within a specific routine need to be performed.

Charge and Spin-State Characterization of Cobalt Bis( o-dioxolene) Valence Tautomers Using Co Kβ X-ray Emission and L-Edge X-ray Absorption Spectroscopies

DOE PAGES

Liang, H. Winnie; Kroll, Thomas; Nordlund, Dennis; ...

2016-12-30

The valence tautomeric states of Co(phen)(3,5-DBQ) 2 and Co(tmeda)(3,5-DBQ) 2, where 3,5-DBQ is either the semiquinone (SQ –) or catecholate (Cat 2–) form of 3,5-di- tert-butyl-1,2-benzoquinone, have been examined by a series of cobalt-specific X-ray spectroscopies. In this work, we have utilized the sensitivity of 1s3p X-ray emission spectroscopy (Kβ XES) to the oxidation and spin states of 3d transition-metal ions to determine the cobalt-specific electronic structure of valence tautomers. A comparison of their Kβ XES spectra with the spectra of cobalt coordination complexes with known oxidation and spin states demonstrates that the low-temperature valence tautomer can be described asmore » a low-spin Co III configuration and the high-temperature valence tautomer as a high-spin Co II configuration. This conclusion is further supported by Co L-edge X-ray absorption spectroscopy (L-edge XAS) of the high-temperature valence tautomers and ligand-field atomic-multiplet calculations of the Kβ XES and L-edge XAS spectra. In conclusion, the nature and strength of the magnetic exchange interaction between the cobalt center and SQ – in cobalt valence tautomers is discussed in view of the effective spin at the Co site from Kβ XES and the molecular spin moment from magnetic susceptibility measurements.« less

Charge and Spin-State Characterization of Cobalt Bis( o-dioxolene) Valence Tautomers Using Co Kβ X-ray Emission and L-Edge X-ray Absorption Spectroscopies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, H. Winnie; Kroll, Thomas; Nordlund, Dennis

The valence tautomeric states of Co(phen)(3,5-DBQ) 2 and Co(tmeda)(3,5-DBQ) 2, where 3,5-DBQ is either the semiquinone (SQ –) or catecholate (Cat 2–) form of 3,5-di- tert-butyl-1,2-benzoquinone, have been examined by a series of cobalt-specific X-ray spectroscopies. In this work, we have utilized the sensitivity of 1s3p X-ray emission spectroscopy (Kβ XES) to the oxidation and spin states of 3d transition-metal ions to determine the cobalt-specific electronic structure of valence tautomers. A comparison of their Kβ XES spectra with the spectra of cobalt coordination complexes with known oxidation and spin states demonstrates that the low-temperature valence tautomer can be described asmore » a low-spin Co III configuration and the high-temperature valence tautomer as a high-spin Co II configuration. This conclusion is further supported by Co L-edge X-ray absorption spectroscopy (L-edge XAS) of the high-temperature valence tautomers and ligand-field atomic-multiplet calculations of the Kβ XES and L-edge XAS spectra. In conclusion, the nature and strength of the magnetic exchange interaction between the cobalt center and SQ – in cobalt valence tautomers is discussed in view of the effective spin at the Co site from Kβ XES and the molecular spin moment from magnetic susceptibility measurements.« less

Normal incidence x-ray mirror for chemical microanalysis

DOEpatents

Carr, M.J.; Romig, A.D. Jr.

1987-08-05

An x-ray mirror for both electron column instruments and micro x-ray fluorescence instruments for making chemical, microanalysis comprises a non-planar mirror having, for example, a spherical reflecting surface for x-rays comprised of a predetermined number of alternating layers of high atomic number material and low atomic number material contiguously formed on a substrate and whose layers have a thickness which is a multiple of the wavelength being reflected. For electron column instruments, the wavelengths of interest lie above 1.5nm, while for x-ray fluorescence instruments, the range of interest is below 0.2nm. 4 figs.

Development of observational and instrumental techniques in hard X-ray and medium energy gamma-ray astronomy

NASA Technical Reports Server (NTRS)

Pelling, M.

1985-01-01

The technical activities, scientific results, related space hardware projects and personnel of the high energy astrophysics program are reported. The development of observational and instrumental techniques in hard X-ray (0.001 to 100 keV) and medium energy gamma-ray (0.1 to 10 MeV) astronomy are examined. Many of these techniques were developed explicitly for use on high altitude balloons where most of the scientific results were obtained. The extensive observational activity using balloons are tabulated. Virtually every research activity will eventually result in a major space hardware development effort.

Role of the Chandra X-Ray Observatory Observations for the Study of Ionized Plasmas

NASA Technical Reports Server (NTRS)

Weisskopf, Martin C.

2010-01-01

The Chandra X-Ray Observatory, launched in 1999, is now beginning its 12-th year of operation. Chandra, the X-ray component of NASA s Great Observatory program, continues to operate efficiently, somewhat remarkable considering that the Observatory was designed for three years of operation with a goal of five. The Observatory features X-ray optics with sub-arcsecond angular resolution and a small suite of instruments, including transmission gratings, which allow for high-resolution spectroscopy of point sources. We will detail the capabilities of the Observatory for making such spectroscopic measurements and discuss a number of examples of what has been learned about the astrophysical plasmas capable of producing bright X-ray emission.

Counting-loss correction for X-ray spectroscopy using unit impulse pulse shaping.

PubMed

Hong, Xu; Zhou, Jianbin; Ni, Shijun; Ma, Yingjie; Yao, Jianfeng; Zhou, Wei; Liu, Yi; Wang, Min

2018-03-01

High-precision measurement of X-ray spectra is affected by the statistical fluctuation of the X-ray beam under low-counting-rate conditions. It is also limited by counting loss resulting from the dead-time of the system and pile-up pulse effects, especially in a high-counting-rate environment. In this paper a detection system based on a FAST-SDD detector and a new kind of unit impulse pulse-shaping method is presented, for counting-loss correction in X-ray spectroscopy. The unit impulse pulse-shaping method is evolved by inverse deviation of the pulse from a reset-type preamplifier and a C-R shaper. It is applied to obtain the true incoming rate of the system based on a general fast-slow channel processing model. The pulses in the fast channel are shaped to unit impulse pulse shape which possesses small width and no undershoot. The counting rate in the fast channel is corrected by evaluating the dead-time of the fast channel before it is used to correct the counting loss in the slow channel.

Reactor for tracking catalyst nanoparticles in liquid at high temperature under a high-pressure gas phase with X-ray absorption spectroscopy.

PubMed

Nguyen, Luan; Tao, Franklin Feng

2018-02-01

Structure of catalyst nanoparticles dispersed in liquid phase at high temperature under gas phase of reactant(s) at higher pressure (≥5 bars) is important for fundamental understanding of catalytic reactions performed on these catalyst nanoparticles. Most structural characterizations of a catalyst performing catalysis in liquid at high temperature under gas phase at high pressure were performed in an ex situ condition in terms of characterizations before or after catalysis since, from technical point of view, access to the catalyst nanoparticles during catalysis in liquid phase at high temperature under high pressure reactant gas is challenging. Here we designed a reactor which allows us to perform structural characterization using X-ray absorption spectroscopy including X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy to study catalyst nanoparticles under harsh catalysis conditions in terms of liquid up to 350 °C under gas phase with a pressure up to 50 bars. This reactor remains nanoparticles of a catalyst homogeneously dispersed in liquid during catalysis and X-ray absorption spectroscopy characterization.

X-ray emission spectroscopy of biomimetic Mn coordination complexes

DOE PAGES

Jensen, Scott C.; Davis, Katherine M.; Sullivan,

2017-05-19

Understanding the function of Mn ions in biological and chemical redox catalysis requires precise knowledge of their electronic structure. X-ray emission spectroscopy (XES) is an emerging technique with a growing application to biological and biomimetic systems. Here, we report an improved, cost-effective spectrometer used to analyze two biomimetic coordination compounds, [Mn IV(OH) 2(Me 2EBC)] 2+ and [Mn IV(O)(OH)(Me 2EBC)] +, the second of which contains a key Mn IV=O structural fragment. Despite having the same formal oxidation state (Mn IV) and tetradentate ligands, XES spectra from these two compounds demonstrate different electronic structures. Experimental measurements and DFT calculations yield differentmore » localized spin densities for the two complexes resulting from Mn IV–OH conversion to Mn IV=O. The relevance of the observed spectroscopic changes is discussed for applications in analyzing complex biological systems such as photosystem II. In conclusion, a model of the S 3 intermediate state of photosystem II containing a Mn IV=O fragment is compared to recent time-resolved X-ray diffraction data of the same state.« less

A Team Approach to the Development of Gamma Ray and x Ray Remote Sensing and in Situ Spectroscopy for Planetary Exploration Missions

NASA Technical Reports Server (NTRS)

Trombka, J. I.; Floyd, S.; Ruitberg, A.; Evans, L.; Starr, R.; Metzger, A.; Reedy, R.; Drake, D.; Moss, C.; Edwards, B.

1993-01-01

An important part of the investigation of planetary origin and evolution is the determination of the surface composition of planets, comets, and asteroids. Measurements of discrete line X-ray and gamma ray emissions from condensed bodies in space can be used to obtain both qualitative and quantitative elemental composition information. The Planetary Instrumentation Definition and Development Program (PIDDP) X-Ray/Gamma Ray Team has been established to develop remote sensing and in situ technologies for future planetary exploration missions.

Single- and double-core-hole ion emission spectroscopy of transient neon plasmas produced by ultraintense x-ray laser pulses

NASA Astrophysics Data System (ADS)

Gao, Cheng; Zeng, Jiaolong; Yuan, Jianmin

2016-02-01

Single-core-hole (SCH) and double-core-hole (DCH) spectroscopy is investigated systematically for neon gas in the interaction with ultraintense x-ray pulses with photon energy from 937 eV to 2000 eV. A time-dependent rate equation, implemented in detailed level accounting approximation, is utilized to study the dynamical evolution of the level population and emission properties of the laser-produced highly transient plasmas. The plasma-density effects on level populations and charge-state distribution are demonstrated with an x-ray photon energy of 2000 eV. It is shown that atomic number density of relevant experiment is about 1 × 1018 cm-3, which is comparable to a recent experiment. At this density, we systematically investigate the emissivity of the transient neon plasmas. For laser photon energy in the range 937-1360 eV, resonant absorptions (RA) of 1s\\to {np} (n≥slant 2) transitions play important roles in time evolution of the population and DCH emission spectroscopy. The RA effects are illustrated in detail for an x-ray pulse of 944 eV photon energy, which creates the 1s\\to 2p RA from the SCH states (1s2{s}22{p}4, 1s2s2p5, and 1s2p6) of Ne3+. After averaging over the space and time distribution of x-ray pulse, DCH emission spectroscopy is studied at x-ray photon energies of 937, 944, 955, 968, 980, and 990 eV, where there exist 1s\\to 2p resonances from SCH states of Ne2+-Ne7+. The processes with producing DCH states are discussed. For x-ray photon energy larger than 1360 eV, no RA exist and transient plasmas show different features in the DCH spectroscopy.

Monte Carlo simulation of X-ray imaging and spectroscopy experiments using quadric geometry and variance reduction techniques

NASA Astrophysics Data System (ADS)

Golosio, Bruno; Schoonjans, Tom; Brunetti, Antonio; Oliva, Piernicola; Masala, Giovanni Luca

2014-03-01

The simulation of X-ray imaging experiments is often performed using deterministic codes, which can be relatively fast and easy to use. However, such codes are generally not suitable for the simulation of even slightly more complex experimental conditions, involving, for instance, first-order or higher-order scattering, X-ray fluorescence emissions, or more complex geometries, particularly for experiments that combine spatial resolution with spectral information. In such cases, simulations are often performed using codes based on the Monte Carlo method. In a simple Monte Carlo approach, the interaction position of an X-ray photon and the state of the photon after an interaction are obtained simply according to the theoretical probability distributions. This approach may be quite inefficient because the final channels of interest may include only a limited region of space or photons produced by a rare interaction, e.g., fluorescent emission from elements with very low concentrations. In the field of X-ray fluorescence spectroscopy, this problem has been solved by combining the Monte Carlo method with variance reduction techniques, which can reduce the computation time by several orders of magnitude. In this work, we present a C++ code for the general simulation of X-ray imaging and spectroscopy experiments, based on the application of the Monte Carlo method in combination with variance reduction techniques, with a description of sample geometry based on quadric surfaces. We describe the benefits of the object-oriented approach in terms of code maintenance, the flexibility of the program for the simulation of different experimental conditions and the possibility of easily adding new modules. Sample applications in the fields of X-ray imaging and X-ray spectroscopy are discussed. Catalogue identifier: AERO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERO_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland

A new nondestructive instrument for bulk residual stress measurement using tungsten kα1 X-ray.

PubMed

Ma, Ce; Dou, Zuo-Yong; Chen, Li; Li, Yun; Tan, Xiao; Dong, Ping; Zhang, Jin; Zheng, Lin; Zhang, Peng-Cheng

2016-11-01

We describe an experimental instrument used for measuring nondestructively the residual stress using short wavelength X-ray, tungsten k α1 . By introducing a photon energy screening technology, the monochromatic X-ray diffraction of tungsten k α1 was realized using a CdTe detector. A high precision Huber goniometer is utilized in order to reduce the error in residual stress measurement. This paper summarizes the main performance of this instrument, measurement depth, stress error, as opposed to the neutron diffraction measurements of residual stress. Here, we demonstrate an application on the determination of residual stress in an aluminum alloy welded by the friction stir welding.

Picosecond sulfur K-edge X-ray absorption spectroscopy with applications to excited state proton transfer

DOE PAGES

Van Kuiken, Benjamin E.; Ross, Matthew R.; Strader, Matthew L.; ...

2017-05-08

Picosecond X-ray absorption (XA) spectroscopy at the S K-edge (~2.4 keV) is demonstrated and used to monitor excited state dynamics in a small organosulfur molecule (2-Thiopyridone, 2TP) following optical excitation. Multiple studies have reported that the thione (2TP) is converted into the thiol (2-Mercaptopyridine, 2MP) following photoexcitation. However, the timescale and photochemical pathway of this reaction remain uncertain. In this work, time-resolved XA spectroscopy at the S K-edge is used to monitor the formation and decay of two transient species following 400nm excitation of 2TP dissolved in acetonitrile. The first transient species forms within the instrument response time (70 ps)more » and decays within 6 ns. The second transient species forms on a timescale of ~400 ps and decays on a 15 ns timescale. Time-dependent density functional theory is used to identify the first and second transient species as the lowestlying triplet states of 2TP and 2MP, respectively. This study demonstrates transient S K-edge XA spectroscopy as a sensitive and viable probe of time-evolving charge dynamics near sulfur sites in small molecules with future applications towards studying complex biological and material systems.« less

X-ray fluorescence beamline at the LNLS: Current instrumentation and future developments (abstract)

NASA Astrophysics Data System (ADS)

Pérez, C. A.; Bueno, M. I. S.; Neuenshwander, R. T.; Sánchez, H. J.; Tolentino, H.

2002-03-01

The x-ray fluorescence (XRF) beamline, constructed at the Brazilian National Synchrotron Radiation Laboratory (LNLS-http://www.lnls.br), has been operating for the external users since August of 1998 (C. A. Pérez et al., Proc. of the European Conference on Energy Dispersive X-Ray Spectrometry, Bologna, Italy, 1998, pp. 125-129). The synchrotron source for this beamline is the D09B (15°) dipole magnet of the LNLS storage ring. Two main experimental setups are mounted at the XRF beamline. One consists of a high vacuum chamber adapted to carry out experiments in grazing excitation conditions. This allows chemical trace and ultratrace element determination on several samples, mainly coming from environmental and biological sciences. Another setup consists of an experimental station, operated in air, in which x-ray fluorescence analysis with spatial resolution can be done. This station is equipped with a fine conical capillary, capable of achieving 20 μm spatial resolution, and with an optical microscope in order to select the region of interest on the sample surface. In this work, the main characteristic of the beamline, experimental stations as well as the description of some new experimental facilities will be given. Future development in the instrumentation focuses on an appropriate x-ray optic to be able to carry out chemical trace analysis of light elements using the total x-ray fluorescence technique. Also, chemical mapping below 10 μm spatial resolution, while keeping high flux of photon on the sample, will be achieved by using the Kirkpatrick-Baez x-ray microfocusing optic.

X-Ray Astronomy Research at the Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Austin, Robert A.

1999-01-01

For at least twenty years, NASA's Marshall Space Flight Center (MSFC) has played a major role in the development of X-ray astronomy in the United States. MSFC scientists and engineers are currently involved in a wide range of programs which will contribute to the growth of X-ray astronomy well into the next century. Areas of activity include calibration of X-ray astronomy instrumentation using Marshall's world-class X-ray Calibration Facility (XRCF), development of high-throughput, replicated X-ray optics, X-ray detector development, balloon-based X-ray astronomy, and analysis of Active Galactic Nuclei (AGNs) and clusters of galaxies. Recent milestones include the successful calibration of NASA's premier X-ray Astronomy Satellite - AXAF (recently renamed Chandra), a balloon flight of a large area (1000 sq cm) micro-strip proportional counter, and work on a hard X-ray (30-100 keV) telescope called HERO, capable of high quality spectroscopy and imaging through the use of grazing incidence optics and an Imaging Gas Scintillation Proportional Counter (IGSPC). In my presentation, I will provide a general overview of our research and facilities. I will conclude with a more detailed discussion of our High Energy Replicated Optics (HERO) program and plans for long duration (>100 days) balloon flights which will take place in the near future.

The Mapping X-ray Fluorescence Spectrometer (MapX)

NASA Astrophysics Data System (ADS)

Sarrazin, P.; Blake, D. F.; Marchis, F.; Bristow, T.; Thompson, K.

2017-12-01

Many planetary surface processes leave traces of their actions as features in the size range 10s to 100s of microns. The Mapping X-ray Fluorescence Spectrometer (MapX) will provide elemental imaging at 100 micron spatial resolution, yielding elemental chemistry at a scale where many relict physical, chemical, or biological features can be imaged and interpreted in ancient rocks on planetary bodies and planetesimals. MapX is an arm-based instrument positioned on a rock or regolith with touch sensors. During an analysis, an X-ray source (tube or radioisotope) bombards the sample with X-rays or alpha-particles / gamma-rays, resulting in sample X-ray Fluorescence (XRF). X-rays emitted in the direction of an X-ray sensitive CCD imager pass through a 1:1 focusing lens (X-ray micro-pore Optic (MPO)) that projects a spatially resolved image of the X-rays onto the CCD. The CCD is operated in single photon counting mode so that the energies and positions of individual X-ray photons are recorded. In a single analysis, several thousand frames are both stored and processed in real-time. Higher level data products include single-element maps with a lateral spatial resolution of 100 microns and quantitative XRF spectra from ground- or instrument- selected Regions of Interest (ROI). XRF spectra from ROI are compared with known rock and mineral compositions to extrapolate the data to rock types and putative mineralogies. When applied to airless bodies and implemented with an appropriate radioisotope source for alpha-particle excitation, MapX will be able to analyze biogenic elements C, N, O, P, S, in addition to the cations of the rock-forming elements >Na, accessible with either X-ray or gamma-ray excitation. The MapX concept has been demonstrated with a series of lab-based prototypes and is currently under refinement and TRL maturation.

Investigating the local structure of B-site cations in (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 using X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Blanchard, Peter E. R.; Grosvenor, Andrew P.

2018-05-01

The structural properties of (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 were investigated using powder X-ray diffraction and X-ray absorption spectroscopy. Diffraction measurements confirmed that substituting small amounts of BiScO3 into BaTiO3 initially stabilizes a cubic phase at x = 0.2 before impurity phases begin to form at x = 0.5. BiScO3 substitution also resulted in noticeable changes in the local coordination environment of Ti4+. X-ray absorption near-edge spectroscopy (XANES) analysis showed that replacing Ti4+ with Sc3+ results in an increase in the off-centre displacement of Ti4+ cations. Surprisingly, BiScO3 substitution has no effect on the displacement of the Ti4+ cation in the (1-x)PbTiO3-xBiScO3 solid solution.

Metalloprotein structures at ambient conditions and in real-time: biological crystallography and spectroscopy using X-ray free electron lasers

DOE PAGES

Kern, Jan; Yachandra, Vittal K.; Yano, Junko

2015-09-02

We have studied the structure of enzymes and the chemistry at the catalytic sites, intensively and have acquired an understanding of the atomic-scale chemistry which requires a new approach beyond steady state X-ray crystallography and X-ray spectroscopy at cryogenic temperatures. Following the dynamic changes in the geometric and electronic structure of metallo-enzymes at ambient conditions, while overcoming the severe X-ray-induced changes to the redox active catalytic center, is key for deriving reaction mechanisms. Such studies become possible by the intense and ultra-short femtosecond (fs) X-ray pulses from an X-ray free electron laser (XFEL) by acquiring a signal before the samplemore » is destroyed. Our review describes the recent and pioneering uses of XFELs to study the protein structure and dynamics of metallo-enzymes using crystallography and scattering, as well as the chemical structure and dynamics of the catalytic complexes (charge, spin, and covalency) using spectroscopy during the reaction to understand the electron-transfer processes and elucidate the mechanism.« less

Metalloprotein structures at ambient conditions and in real-time: biological crystallography and spectroscopy using X-ray free electron lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kern, Jan; Yachandra, Vittal K.; Yano, Junko

We have studied the structure of enzymes and the chemistry at the catalytic sites, intensively and have acquired an understanding of the atomic-scale chemistry which requires a new approach beyond steady state X-ray crystallography and X-ray spectroscopy at cryogenic temperatures. Following the dynamic changes in the geometric and electronic structure of metallo-enzymes at ambient conditions, while overcoming the severe X-ray-induced changes to the redox active catalytic center, is key for deriving reaction mechanisms. Such studies become possible by the intense and ultra-short femtosecond (fs) X-ray pulses from an X-ray free electron laser (XFEL) by acquiring a signal before the samplemore » is destroyed. Our review describes the recent and pioneering uses of XFELs to study the protein structure and dynamics of metallo-enzymes using crystallography and scattering, as well as the chemical structure and dynamics of the catalytic complexes (charge, spin, and covalency) using spectroscopy during the reaction to understand the electron-transfer processes and elucidate the mechanism.« less

X ray spectra of X Per. [oso-8 observations

NASA Technical Reports Server (NTRS)

Becker, R. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Robinson-Saba, J.; Serlemitsos, P. J.; Swank, J. H.

1978-01-01

The cosmic X-ray spectroscopy experiment on OSO-8 observed X Per for twenty days during two observations in Feb. 1976 and Feb. 1977. The spectrum of X Per varies in phase with its 13.9 min period, hardening significantly at X-ray minimum. Unlike other X-ray binary pulsar spectra, X Per's spectra do not exhibit iron line emission or strong absorption features. The data show no evidence for a 22 hour periodicity in the X-ray intensity of X Per. These results indicate that the X-ray emission from X Per may be originating from a neutron star in a low density region far from the optically identified Be star.

Single and double core-hole ion emission spectroscopy of transient neon plasmas produced by ultraintense x-ray laser pulses

NASA Astrophysics Data System (ADS)

Gao, Cheng; Zeng, Jiaolong; Yuan, Jianmin

2016-05-01

Single core-hole (SCH) and double core-hole (DCH) spectroscopy is investigated systematically for neon gas in the interaction with ultraintense x-ray pulses with photon energy from 937 eV to 2000 eV. A time-dependent rate equation, implemented in the detailed level accounting approximation, is utilized to study the dynamical evolution of the level population and emission properties of the laser-produced highly transient plasmas. The plasma density effects on level populations are demonstrated with an x-ray photon energy of 2000 eV. For laser photon energy in the range of 937 - 1360 eV, resonant absorptions (RA) of 1s-np (n> = 2) transitions play important roles in time evolution of the population and DCH emission spectroscopy. For x-ray photon energy larger than 1360 eV, no RA exist and transient plasmas show different features in the DCH spectroscopy.

Black hole accretion rings revealed by future X-ray spectroscopy

NASA Astrophysics Data System (ADS)

Sochora, V.; Karas, V.; Svoboda, J.; Dovčiak, M.

2011-11-01

Spectral features can arise by reflection of coronal X-rays on a black hole accretion disc. The resulting profile bears various imprints of a strong gravitational field acting on the light-emitting gas. The observed shape of the reflection line is formed by integrating contributions over a range of radii across the accretion disc plane, where the individual photons experience a different level of energy shifts, boosting and amplification by relativistic effects. These have to be convolved with the intrinsic emissivity of the line, which is a function of radius and the emission angle in the local frame. We study if the currently discussed instruments on-board X-ray satellites will be able to reveal the departure of the line radial emissivity from a simple smooth power-law function, which is often assumed in data fitting and its interpretation. Such a departure can be a result of excess emission occurring at a certain distance. This could be used to study variations with a radius of the line production or to constrain the position of the inner edge of the accretion disc. By simulating artificial data from a bright active galactic nucleus of a type 1 Seyfert galaxy (inclination ≃30°, X-ray flux ≃1-2 mCrab in a keV energy band) we show that the required sensitivity and energy resolution could be reached with a large area detector of the proposed Large Observatory for X-ray Timing mission. Galactic black holes will provide another category of potentially suitable targets if the relativistic spectral features are indeed produced by reflection from their accretion discs.

Gamma ray spectroscopy in astrophysics. [conferences

NASA Technical Reports Server (NTRS)

Cline, T. L. (Editor); Ramaty, R. (Editor)

1978-01-01

Experimental and theoretical aspects of gamma ray spectroscopy in high energy astrophysics are discussed. Line spectra from solar, stellar, planetary, and cosmic gamma rays are examined as well as HEAO investigations, the prospects of a gamma ray observatory, and follow-on X-ray experiments in space.

High-Resolution Spectroscopy with the Chandra X-ray Observatory

ScienceCinema

Canizares, Claude R. [MIT, Cambridge, Massachusetts, United States

2017-12-09

The capabilities of the Chandra X-ray Observatory and XMM-Newton for high-resolution spectroscopy have brought tradition plasma diagnostic techniques to the study of cosmic plasma. Observations have probed nearly every class of astronomical object, from young proto-starts through massive O starts and black hole binaries, supernova remnants, active galactic nuclei, and the intergalactic medium. Many of these sources show remarkable rich spectra that reveal new physical information, such as emission measure distributions, elemental abundances, accretion disk and wind signatures, and time variability. This talk will present an overview of the Chandra instrumentaton and selected examples of spectral observations of astrophysical and cosmological importance.

The hard x-ray imager onboard IXO

NASA Astrophysics Data System (ADS)

Nakazawa, Kazuhiro; Takahashi, Tadayuki; Limousin, Olivier; Kokubun, Motohide; Watanabe, Shin; Laurent, Philippe; Arnaud, Monique; Tajima, Hiroyasu

2010-07-01

The Hard X-ray Imager (HXI) is one of the instruments onboard International X-ray Observatory (IXO), to be launched into orbit in 2020s. It covers the energy band of 10-40 keV, providing imaging-spectroscopy with a field of view of 8 x 8 arcmin2. The HXI is attached beneath the Wide Field Imager (WFI) covering 0.1-15 keV. Combined with the super-mirror coating on the mirror assembly, this configuration provides observation of X-ray source in wide energy band (0.1-40.0 keV) simultaneously, which is especially important for varying sources. The HXI sensor part consists of the semiconductor imaging spectrometer, using Si in the medium energy detector and CdTe in the high energy detector as its material, and an active shield covering its back to reduce background in orbit. The HXI technology is based on those of the Japanese-lead new generation X-ray observatory ASTRO-H, and partly from those developed for Simbol-X. Therefore, the technological development is in good progress. In the IXO mission, HXI will provide a major assets to identify the nature of the object by penetrating into thick absorbing materials and determined the inherent spectral shape in the energy band well above the structure around Fe-K lines and edges.

Non-conventional applications of a noninvasive portable X-ray diffraction/fluorescence instrument

NASA Astrophysics Data System (ADS)

Chiari, Giacomo; Sarrazin, Philippe; Heginbotham, Arlen

2016-11-01

Noninvasive techniques have become widespread in the cultural heritage analytical domain. The popular handheld X-ray fluorescence (XRF) devices give the elemental composition of all the layers that X-rays can penetrate, but no information on how atoms are bound together or at which depth they are located. A noninvasive portable X-ray powder diffraction/X-ray fluorescence (XRD/XRF) device may offer a solution to these limitations, since it can provide information on the composition of crystalline materials. This paper introduces applications of XRD beyond simple phase recognition. The two fundamental principles for XRD are: (1) the crystallites should be randomly oriented, to ensure proper intensity to all the diffraction peaks, and (2) the material should be positioned exactly in the focal plane of the instrument, respecting its geometry, as any displacement of the sample would results in 2 θ shifts of the diffraction peaks. In conventional XRD, the sample is ground and set on the properly positioned sample holder. Using a noninvasive portable instrument, these two requirements are seldom fulfilled. The position, size and orientation of a given crystallite within a layered structure depend on the object itself. Equation correlating the displacement (distance from the focal plane) versus peak shift (angular difference in 2 θ from the standard value) is derived and used to determine the depth at which a given substance is located. The quantitative composition of two binary Cu/Zn alloys, simultaneously present, was determined measuring the cell volume and using Vegard's law. The analysis of the whole object gives information on the texture and possible preferred orientations of the crystallites, which influences the peak intensity. This allows for the distinction between clad and electroplated daguerreotypes in the case of silver and between ancient and modern gilding for gold. Analyses of cross sections can be carried out successfully. Finally, beeswax, used in

X-ray spectroscopy of the mixed morphology supernova remnant W 28 with XMM-Newton

NASA Astrophysics Data System (ADS)

Nakamura, Ryoko; Bamba, Aya; Ishida, Manabu; Yamazaki, Ryo; Tatematsu, Ken'ichi; Kohri, Kazunori; Pühlhofer, Gerd; Wagner, Stefan J.; Sawada, Makoto

2014-06-01

We report on spatially resolved X-ray spectroscopy of the north-eastern part of the mixed morphology supernova remnant (SNR) W 28 with XMM-Newton. The observed field of view includes a prominent and twisted shell emission forming the edge of this SNR as well as part of the center-filled X-ray emission brightening toward the south-west edge of the field of view. The shell region spectra are in general represented by an optically thin thermal plasma emission in collisional ionization equilibrium with a temperature of ˜ 0.3 keV and a density of ˜ 10 cm-3, which is much higher than the density obtained for inner parts. In contrast, we detected no significant X-ray flux from one of the TeV γ-ray peaks with an upper-limit flux of 2.1 × 10-14 erg cm-2 s-1 in the 2-10 keV band. The large flux ratio of TeV to X-ray, larger than 16, and the spatial coincidence of the molecular cloud and the TeV γ-ray emission site indicate that the TeV γ-ray of W 28 is π0-decay emission originating from collisions between accelerated protons and molecular cloud protons. Comparing the spectrum in the TeV band and the X-ray upper limit, we obtained a weak upper limit on the magnetic field strength B ≲ 1500 μG.

Revealing the electronic structure of LiC 6 by soft X-ray spectroscopy

DOE PAGES

Zhang, L.; Li, X.; Augustsson, A.; ...

2017-03-09

The electronic structure of LiC 6 has been investigated in this paper by soft X-ray absorption and emission spectroscopies. The results reveal that upon full lithiation of graphite, the Li 2s electrons are transferred into the carbon π* states in a near rigid-band behavior, resulting in the increased density of states near E F and the shift of σ* states to lower energies. Finally, in addition, the resonant inelastic X-ray scattering spectra of LiC 6 do not show strong dispersive features as that of graphite, indicating that the crystal momentum is not conserved during the scattering process due to themore » delocalization of electrons in the intermediate state.« less

Methods development for diffraction and spectroscopy studies of metalloenzymes at X-ray free-electron lasers

PubMed Central

Kern, Jan; Hattne, Johan; Tran, Rosalie; Alonso-Mori, Roberto; Laksmono, Hartawan; Gul, Sheraz; Sierra, Raymond G.; Rehanek, Jens; Erko, Alexei; Mitzner, Rolf; Wernet, Phillip; Bergmann, Uwe; Sauter, Nicholas K.; Yachandra, Vittal; Yano, Junko

2014-01-01

X-ray free-electron lasers (XFELs) open up new possibilities for X-ray crystallographic and spectroscopic studies of radiation-sensitive biological samples under close to physiological conditions. To facilitate these new X-ray sources, tailored experimental methods and data-processing protocols have to be developed. The highly radiation-sensitive photosystem II (PSII) protein complex is a prime target for XFEL experiments aiming to study the mechanism of light-induced water oxidation taking place at a Mn cluster in this complex. We developed a set of tools for the study of PSII at XFELs, including a new liquid jet based on electrofocusing, an energy dispersive von Hamos X-ray emission spectrometer for the hard X-ray range and a high-throughput soft X-ray spectrometer based on a reflection zone plate. While our immediate focus is on PSII, the methods we describe here are applicable to a wide range of metalloenzymes. These experimental developments were complemented by a new software suite, cctbx.xfel. This software suite allows for near-real-time monitoring of the experimental parameters and detector signals and the detailed analysis of the diffraction and spectroscopy data collected by us at the Linac Coherent Light Source, taking into account the specific characteristics of data measured at an XFEL. PMID:24914169

The use of C-near edge X-ray absorption fine structure spectroscopy for the elaboration of chemistry in lignocellulosics

Treesearch

Lucian A. Lucia; Hiroki Nanko; Alan W. Rudie; Doug G. Mancosky; Sue Wirick

2006-01-01

The research presented elucidates the oxidation chemistry occurring in hydrogen peroxide bleached kraft pulp fibers by employing carbon near edge x-ray absorption fine structure spectroscopy (C-NEXAFS). C-NEXAFS is a soft x-ray technique that selectively interrogates atomic moieties using photoelectrons (Xrays) of variable energies. The X1A beam line at the National...

Novel visualization studies of lignocellulosic oxidation chemistry by application of C-near edge X-ray absorption fine structure spectroscopy

Treesearch

Douglas G. Mancosky; Lucian A. Lucia; Hiroki Nanko; Sue Wirick; Alan W. Rudie; Robert Braun

2005-01-01

The research presented herein is the first attempt to probe the chemical nature of lignocellulosic samples by the application of carbon near edge X-ray absorption fine structure spectroscopy (C-NEXAFS). C-NEXAFS is a soft X-ray technique that principally provides selective interrogation of discrete atomic moieties using photoelectrons of variable energies. The X1A beam...

Femtosecond time-resolved X-ray absorption spectroscopy of anatase TiO2 nanoparticles using XFEL

PubMed Central

Obara, Yuki; Ito, Hironori; Ito, Terumasa; Kurahashi, Naoya; Thürmer, Stephan; Tanaka, Hiroki; Katayama, Tetsuo; Togashi, Tadashi; Owada, Shigeki; Yamamoto, Yo-ichi; Karashima, Shutaro; Nishitani, Junichi; Yabashi, Makina; Suzuki, Toshinori; Misawa, Kazuhiko

2017-01-01

The charge-carrier dynamics of anatase TiO2 nanoparticles in an aqueous solution were studied by femtosecond time-resolved X-ray absorption spectroscopy using an X-ray free electron laser in combination with a synchronized ultraviolet femtosecond laser (268 nm). Using an arrival time monitor for the X-ray pulses, we obtained a temporal resolution of 170 fs. The transient X-ray absorption spectra revealed an ultrafast Ti K-edge shift and a subsequent growth of a pre-edge structure. The edge shift occurred in ca. 100 fs and is ascribed to reduction of Ti by localization of generated conduction band electrons into shallow traps of self-trapped polarons or deep traps at penta-coordinate Ti sites. Growth of the pre-edge feature and reduction of the above-edge peak intensity occur with similar time constants of 300–400 fs, which we assign to the structural distortion dynamics near the surface. PMID:28713842

Time Resolved Spectroscopy, High Sensitivity Power Spectrum & a Search for the X-Ray QPO in NGC 5548

NASA Astrophysics Data System (ADS)

Yaqoob, Tahir

1999-09-01

Controversy surrounds the EXOSAT discovery of a QPO (period ~500 s) in NGC 5548 due to the data being plagued by high background and instrumental systematics. If the NGC 5548 QPO is real, the implications for the physics of the X-ray emission mechanism and inner-most disk/black-hole system are enormous. AXAF provides the first opportunity to settle the issue, capable of yielding power spectra with unprecedented sensitivity, pushing the limit on finding new features. Using HETG/ACIS we will also perform time-resolved spectroscopy of the ionized absorption features and Fe-K emission line, search for energy-dependent time lags in the continuum, between the continuum and spectral features, and between the spectral features. These data will provide powerful constraints on models of AGN.

High resolution x-ray absorption and emission spectroscopy of Li x CoO2 single crystals as a function delithiation

NASA Astrophysics Data System (ADS)

Simonelli, L.; Paris, E.; Iwai, C.; Miyoshi, K.; Takeuchi, J.; Mizokawa, T.; Saini, N. L.

2017-03-01

The effect of delithiation in Li x CoO2 is studied by high resolution Co K-edge x-ray absorption and x-ray emission spectroscopy. Polarization dependence of the x-ray absorption spectra on single crystal samples is exploited to reveal information on the anisotropic electronic structure. We find that the electronic structure of Li x CoO2 is significantly affected by delithiation in which the Co ions oxidation state tending to change from 3+  to 4+. The Co intersite (intrasite) 4p-3d hybridization suffers a decrease (increase) by delithiation. The unoccupied 3d t 2g orbitals with a 1g symmetry, containing substantial O 2p character, hybridize isotropically with Co 4p orbitals and likely to have itinerant character unlike anisotropically hybridized 3d e g orbitals. Such a peculiar electronic structure could have significant effect on the mobility of Li in Li x CoO2 cathode and hence the battery characteristics.

Data reduction and analysis for the graphite crystal X-ray spectrometer and polarimeter experiment flown aboard OSO-8 spacecraft

NASA Technical Reports Server (NTRS)

Novick, R.

1980-01-01

The documentation and software programs developed for the reception, initial processing (quickbook), and production analysis of data obtained by solar X-ray spectroscopy, stellar spectroscopy, and X-ray polarimetry experiments on OSO-8 are listed. The effectiveness and sensitivity of the Bragg crystal scattering instruments used are assessed. The polarization data polarimetric data obtained shows that some X-ray sources are polarized and that a larger polarimeter of this type is required to perform the measurements necessary to fully understand the physics of X-ray sources. The scanning Bragg crystal spectrometer was ideally suited for studying rapidly changing solar conditions. Observations of the Crab Nebula and pulsar, Cyg X-1, Cyg X-2, Cyg X-3, Sco X-1, Cen X-3, and Her X-1 are discussed as well as of 4U1656-53 and 4U1820-30. Evidence was obtained for iron line emission from Cyg X-3.

Application of the gas-discharge surge arresters in X-ray devices and low voltage instrumentation

NASA Astrophysics Data System (ADS)

Simon, V. A.; Gerasimov, V. A.; Kostrin, D. K.; Lisenkov, A. A.; Selivanov, L. M.; Uhov, A. A.

2018-02-01

Usage of the gas discharge in science and engineering is discussed. Application examples of the compact gas-discharge tubes in the X-ray devices and low voltage instrumentation appliances for the surge protection are presented.

Confocal total reflection X-ray fluorescence technology based on an elliptical monocapillary and a parallel polycapillary X-ray optics.

PubMed

Zhu, Yu; Wang, Yabing; Sun, Tianxi; Sun, Xuepeng; Zhang, Xiaoyun; Liu, Zhiguo; Li, Yufei; Zhang, Fengshou

2018-07-01

A total reflection X-ray fluorescence (TXRF) spectrometer based on an elliptical monocapillary X-ray lens (MXRL) and a parallel polycapillary X-ray lens (PPXRL) was designed. This TXRF instrument has micro focal spot, low divergence and high intensity of incident X-ray beam. The diameter of the focal spot of MXRL was 16.5 µm, and the divergence of the incident X-ray beam was 3.4 mrad. We applied this TXRF instrument to the micro analysis of a single-layer film containing Ni deposited on a Si substrate by metal vapor vacuum arc ion source. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spectra of cosmic X-ray sources

NASA Technical Reports Server (NTRS)

Holt, S. S.; Mccray, R.

1982-01-01

X-ray measurements provide the most direct probes of astrophysical environments with temperatures exceeding one million K. Progress in experimental research utilizing dispersive techniques (e.g., Bragg and grating spectroscopy) is considerably slower than that in areas utilizing photometric techniques, because of the relative inefficiency of the former for the weak X-ray signals from celestial sources. As a result, the term "spectroscopy" as applied to X-ray astronomy has traditionally satisfied a much less restrictive definition (in terms of resolving power) than it has in other wavebands. Until quite recently, resolving powers of order unity were perfectly respectable, and still provide (in most cases) the most useful spectroscopic data. In the broadest sense, X-ray photometric measurements are spectroscopic, insofar as they represent samples of the overall electromagnetic continua of celestial objects.

Mineralogy by X-ray Diffraction on Mars: The Chemin Instrument on Mars Science Laboratory

NASA Technical Reports Server (NTRS)

Vaniman, D. T.; Bristow, T. F.; Bish, D. L.; Ming, D. W.; Blake, D. F.; Morris, R. V.; Rampe, E. B.; Chipera, S. J.; Treiman, A. H.; Morrison, S. M.;

A flexible gas flow reaction cell for in situ x-ray absorption spectroscopy studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroner, Anna B., E-mail: anna.kroner@diamond.ac.uk; Gilbert, Martin; Duller, Graham

2016-07-27

A capillary-based sample environment with hot air blower and integrated gas system was developed at Diamond to conduct X-ray absorption spectroscopy (XAS) studies of materials under time-resolved, in situ conditions. The use of a hot air blower, operating in the temperature range of 298-1173 K, allows introduction of other techniques e.g. X-ray diffraction (XRD), Raman spectroscopy for combined techniques studies. The flexibility to use either quartz or Kapton capillaries allows users to perform XAS measurement at energies as low as 5600 eV. To demonstrate performance, time-resolved, in situ XAS results of Rh catalysts during the process of activation (Rh K-edge,more » Ce L{sub 3}-edge and Cr K-edge) and the study of mixed oxide membrane (La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3−δ}) under various partial oxygen pressure conditions are described.« less

Combining X-ray and neutron crystallography with spectroscopy.

PubMed

Kwon, Hanna; Smith, Oliver; Raven, Emma Lloyd; Moody, Peter C E

2017-02-01

X-ray protein crystallography has, through the determination of the three-dimensional structures of enzymes and their complexes, been essential to the understanding of biological chemistry. However, as X-rays are scattered by electrons, the technique has difficulty locating the presence and position of H atoms (and cannot locate H + ions), knowledge of which is often crucially important for the understanding of enzyme mechanism. Furthermore, X-ray irradiation, through photoelectronic effects, will perturb the redox state in the crystal. By using single-crystal spectrophotometry, reactions taking place in the crystal can be monitored, either to trap intermediates or follow photoreduction during X-ray data collection. By using neutron crystallography, the positions of H atoms can be located, as it is the nuclei rather than the electrons that scatter neutrons, and the scattering length is not determined by the atomic number. Combining the two techniques allows much greater insight into both reaction mechanism and X-ray-induced photoreduction.

Prototyping a Global Soft X-ray Imaging Instrument for Heliophysics, Planetary Science, and Astrophysics Science

NASA Technical Reports Server (NTRS)

Collier, Michael R.; Porter, F. Scott; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chornay, Dennis J.; Cravens, Thomas; Galeazzi, Massimiliano; Keller, John W.; Koutroumpa, Dimitra;

Prototyping a Global Soft X-Ray Imaging Instrument for Heliophysics, Planetary Science, and Astrophysics Science

NASA Technical Reports Server (NTRS)

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.;

The Compton-thick AGN fraction from the deepest X-ray spectroscopy in the CDF-S

NASA Astrophysics Data System (ADS)

Corral, A.; Georgantopoulos, I.; Akylas, A.; Ranalli, P.

2017-10-01

Highly obscured AGN, especially Compton-thick (CT) AGN, likely play a key role in the galaxy-AGN co-evolution scenario. They would comprise the early stages of AGN activity, preceding the AGN-feedback/star-formation quenching phase, during which most of both the SMBH and galaxy growth take place. However, the actual CT fraction among the AGN population is still largely unconstrained. The most reliable way of confirming the obscured nature of an AGN by X-ray spectroscopy, but very deep observations are needed to extend local analyses to larger distances. We will present the X-ray spectral analysis of the deepest X-ray data obtained to date, the almost 7Ms observation of the Chandra Deep Field South. The unprecedented depth of this survey allow us to carry out reliable spectral analyses down to a flux limit of 10^{-16} erg cm^{-2} s^{-1} in the hard 2-8 keV band. Besides the new deeper X-ray data, our approach also includes the implementation of Bayesian inference in the determination of the CT fraction. Our results favor X-ray background synthesis models which postulate a moderate fraction (25%) of CT objects among the obscured AGN population.

Progress report on the Astro-H Soft X-Ray Spectrometer

NASA Astrophysics Data System (ADS)

Kelley, Richard L.; Mitsuda, Kazuhisa

2016-04-01

We describe the initial in-orbit operations and performance of the Astro-H Soft X-Ray Spectrometer (SXS). Astro-H, JAXA's sixth X-ray observatory, is scheduled for launch on February 12, 2016, from the Tanegashima Space Center in Japan abord an H-IIA rocket. The instrument is based on a 36-pixel array of microcalorimeters designed for high resolution over the 0.3-12 keV energy band at the focus of a high throughput, grazing-incidence x-ray mirror. The instrument is the result of a joint collaboration between the JAXA Institute of Space and Astronautical Science and many partners in Japan, and the NASA/Goddard Space Flight Center and collaborators in the US. The principal components of the spectrometer are the microcalorimeter detector system, a low-temperature anticoincidence detector, a 3-stage adiabatic demagnetization refrigerator (ADR) to maintain 50 mK operation under both cryogen and cryogen-free operation, a hybrid liquid helium/cryogen-free dewar with both Stirling and Joule-Thomson coolers, electronics for reading out the array, processing the x-ray data for spectroscopy, and operating the ADR and cryocoolers. The dewar is closed out by an aperture system with five thin-film filters designed to provide high x-ray transmission with low heat loads to the dewar and detector system, and prevent contamination from condensing on the filters. The instrument was designed to have better than 7 eV energy resolution, and was demonstrated to achieve 4-5 eV resolution across the array at the full spacecraft level of integration during extensive ground testing prior to launch. The overall cooling chain has been designed to provide a lifetime of at least 3 years in orbit, and continue to operate without liquid helium to provide redundancy and the longest operational lifetime for the instrument. In this presentation, we will describe the early phases of the SXS instrument in orbit and provide a sense of the astronomical results that can be expected. This presentation is

Sulfur Speciation in Biochars by Very High Resolution Benchtop Kα X-ray Emission Spectroscopy.

PubMed

Holden, William M; Seidler, Gerald T; Cheah, Singfoong

2018-05-30

The analytical chemistry of sulfur-containing materials poses substantial technical challenges, especially due to the limitations of 33 S NMR and the time-intensive preparations required for wet-chemistry analyses. A number of prior studies have found that synchrotron-based X-ray absorption near edge structure (XANES) measurements can give detailed speciation of sulfur chemistry in such cases. However, due to the obvious access limitations, synchrotron XANES of sulfur cannot be part of routine analytical practice across the chemical sciences community. Here, in a study of the sulfur chemistry in biochars, we compare and contrast the chemical inferences available from synchrotron XANES with that given by benchtop, extremely high resolution wavelength-dispersive X-ray fluorescence (WD-XRF) spectroscopy, also often called X-ray emission spectroscopy (XES). While the XANES spectra have higher total information content, often giving differentiation between different moieties having the same oxidation state, the lower sensitivity of the S Kα XES to coordination and local structure provides pragmatic benefit for the more limited goal of quantifying the S oxidation state distribution. Within that constrained metric, we find good agreement between the two methods. As the sulfur concentrations were as low as 150 ppm, these measurements provide proof-of-principle for characterization of the sulfur chemistry of biochars and potential applications to other areas such as soils, batteries, catalysts, and fossil fuels and their combustion products.

X-rays from the Solar System

NASA Astrophysics Data System (ADS)

Dennerl, K.

2017-10-01

While the beginning of X-ray astronomy was motivated by solar system studies (Sun and Moon), the main research interest soon shifted outwards to much more distant and exotic objects. However, the ROSAT discovery of X-rays from comets in 1996 and the insight that this `new' kind of X-ray emission, charge exchange, was underestimated for a long time, has demonstrated that solar system studies are still important for X-ray astrophysics in general. While comets provide the best case for studying the physics of charge exchange, the X-ray signatures of this process have now also been detected at Venus, Mars, and Jupiter, thanks to Chandra and XMM-Newton. An analysis of the X-ray data of solar system objects, however, is challenging in many respects. This is particularly true for comets, which appear as moving, extended X-ray sources, emitting a line-rich spectrum at low energies. Especially for XMM-Newton, which has the unparalleled capability to observe with five highly sensitive X-ray instruments plus an optical monitor simultaneously, it is a long way towards photometrically and spectroscopically calibrated results, which are consistent between all its instruments. I will show this in my talk, where I will also summarize the current state of solar system X-ray research.

Hard x-ray imager for the NeXT mission

NASA Astrophysics Data System (ADS)

Nakazawa, Kazuhiro; Fukazawa, Yasushi; Kamae, Tuneyoshi; Kataoka, Jun; Kokubun, Motohide; Makishima, Kazuo; Mizuno, Tsunefumi; Murakami, Toshio; Nomachi, Masaharu; Tajima, Hiroyasu; Takahashi, Tadayuki; Tashiro, Makoto; Tamagawa, Toru; Terada, Yukikatsu; Watanabe, Shin; Yamaoka, Kazutaka; Yonetoku, Daisuke

2006-06-01

The hard X-ray imager (HXI) is the primary detector of the NeXT mission, proposed to explore high-energy non-thermal phenomena in the universe. Combined with a novel hard X-ray mirror optics, the HXI is designed to provide better than arc-minutes imaging capability with 1 keV level spectroscopy, and more than 30 times higher sensitivity compared with any existing hard X-ray instruments. The base-line design of the HXI is improving to secure high sensitivity. The key is to reduce the detector background as far as possible. Based on the experience of the Suzaku satellite launched in July 2005, the current design has a well-type tight active shield and multi layered, multi material imaging detector made of Si and CdTe. Technology has been under development for a few years so that we have reached the level where a basic detector performance is satisfied. Design tuning to further improve the sensitivity and reliability is on-going.

Small Pixel Hybrid CMOS X-ray Detectors

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

Simulation and Laboratory results of the Hard X-ray Polarimeter: X-Calibur

NASA Astrophysics Data System (ADS)

Guo, Qingzhen; Beilicke, M.; Kislat, F.; Krawczynski, H.

2014-01-01

X-ray polarimetry promises to give qualitatively new information about high-energy sources, such as binary black hole (BH) systems, Microquasars, active galactic nuclei (AGN), GRBs, etc. We designed, built and tested a hard X-ray polarimeter 'X-Calibur' to be flown in the focal plane of the InFOCuS grazing incidence hard X-ray telescope in 2014. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 20- 80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the E field orientation. X-Calibur achieves a high detection efficiency of order unity. We optimized of the design of the instrument based on Monte Carlo simulations of polarized and unpolarized X-ray beams and of the most important background components. We have calibrated and tested X-Calibur extensively in the laboratory at Washington University and at the Cornell High-Energy Synchrotron Source (CHESS). Measurements using the highly polarized synchrotron beam at CHESS confirm the polarization sensitivity of the instrument. In this talk we report on the optimization of the design of the instrument based on Monte Carlo simulations, as well as results of laboratory calibration measurements characterizing the performance of the instrument.

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

NASA Astrophysics Data System (ADS)

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

2016-06-01

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

Extreme ultraviolet and X-ray spectroheliograph for OSO-H

NASA Technical Reports Server (NTRS)

Sterk, A. A.; Kieser, F.; Peck, S.; Knox, E.

1972-01-01

A complex scientific instrument was designed, fabricated, tested, and calibrated for launch onboard OSO-H. This instrument consisted of four spectroheliographs and an X-ray polarimeter. The instrument is designed to study solar radiation at selected wavelengths in the X-ray and the extreme ultraviolet ranges, make observations at the H-alpha wavelength, and measure the degree of polarization of X-ray emissions.

Characterization of Sb-doped Bi(2)UO(6) solid solutions by X-ray diffraction and X-ray absorption spectroscopy.

PubMed

Misra, N L; Yadav, A K; Dhara, Sangita; Mishra, S K; Phatak, Rohan; Poswal, A K; Jha, S N; Sinha, A K; Bhattacharyya, D

2013-01-01

The preparation and characterization of Sb-doped Bi(2)UO(6) solid solutions, in a limited composition range, is reported for the first time. The solid solutions were prepared by solid-state reactions of Bi(2)O(3), Sb(2)O(3) and U(3)O(8) in the required stoichiometry. The reaction products were characterized by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements at the Bi and U L(3) edges. The XRD patterns indicate the precipitation of additional phases in the samples when Sb doping exceeds 4 at%. The chemical shifts of the Bi absorption edges in the samples, determined from the XANES spectra, show a systematic variation only up to 4 at% of Sb doping and support the results of XRD measurements. These observations are further supported by the local structure parameters obtained by analysis of the EXAFS spectra. The local structure of U is found to remain unchanged upon Sb doping indicating that Sb(+3) ions replace Bi(+3) during the doping of Bi(2)UO(6) by Sb.

Development of soft x-ray time-resolved photoemission spectroscopy system with a two-dimensional angle-resolved time-of-flight analyzer at SPring-8 BL07LSU

NASA Astrophysics Data System (ADS)

Ogawa, Manami; Yamamoto, Susumu; Kousa, Yuka; Nakamura, Fumitaka; Yukawa, Ryu; Fukushima, Akiko; Harasawa, Ayumi; Kondoh, Hiroshi; Tanaka, Yoshihito; Kakizaki, Akito; Matsuda, Iwao

2012-02-01

We have developed a soft x-ray time-resolved photoemission spectroscopy system using synchrotron radiation (SR) at SPring-8 BL07LSU and an ultrashort pulse laser system. Two-dimensional angle-resolved measurements were performed with a time-of-flight-type analyzer. The photoemission spectroscopy system is synchronized to light pulses of SR and laser using a time control unit. The performance of the instrument is demonstrated by mapping the band structure of a Si(111) crystal over the surface Brillouin zones and observing relaxation of the surface photo-voltage effect using the pump (laser) and probe (SR) method.

Development of soft x-ray time-resolved photoemission spectroscopy system with a two-dimensional angle-resolved time-of-flight analyzer at SPring-8 BL07LSU.

PubMed

Ogawa, Manami; Yamamoto, Susumu; Kousa, Yuka; Nakamura, Fumitaka; Yukawa, Ryu; Fukushima, Akiko; Harasawa, Ayumi; Kondoh, Hiroshi; Tanaka, Yoshihito; Kakizaki, Akito; Matsuda, Iwao

2012-02-01

We have developed a soft x-ray time-resolved photoemission spectroscopy system using synchrotron radiation (SR) at SPring-8 BL07LSU and an ultrashort pulse laser system. Two-dimensional angle-resolved measurements were performed with a time-of-flight-type analyzer. The photoemission spectroscopy system is synchronized to light pulses of SR and laser using a time control unit. The performance of the instrument is demonstrated by mapping the band structure of a Si(111) crystal over the surface Brillouin zones and observing relaxation of the surface photo-voltage effect using the pump (laser) and probe (SR) method.

Crystals for astronomical X-ray spectroscopy

NASA Technical Reports Server (NTRS)

Burek, A.

1976-01-01

Crystal spectrometric properties and the factors that affect their measurement are discussed. Theoretical and experimental results on KAP are summarized and theoretical results based on the dynamical theory of X-ray diffraction are given for the acid phthalates as well as for the commonly used planes of ADP, PET and EDDT. Anomalous dispersion is found to be important for understanding the details of crystal Bragg reflection properties at long X-ray wavelengths and some important effects are pointed out. The theory of anomalous dispersion is applied to explain the anomalous reflectivity exhibited by KAP at 23.3 A.

UTEX: integrated ultraviolet and x-ray astronomy facility on spacelab, phase a study. Volume 1: executive summary. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1976-07-01

A multipurpose UV telescope coupled with an X-ray detector to be flown on Spacelab is described. The instrument is capable of operating in the following basic modes: imagery over a field of 1 deg 65 with a focal ratio of f/2, time resolved rapid photometry correlated with X-ray observations, spectroscopy of both point-like and extended sources, and objective grating spectroscopy. The optical layout is a 60 cm f/8 Ritchey-Chretien configuration with f/2.4 Schmidt class focal reducer. The X-ray detector is a four layer multiwire proportional counter. The engineering effort was oriented to identify possible system configurations satisfying both scientific requirementsmore » and Spacelab interfaces and constraints.« less

X-ray absorption spectroscopy study of Gd3+-loaded ultra-short carbon nanotubes

NASA Astrophysics Data System (ADS)

Ma, Q.; Jebb, M.; Tweedle, M. F.; Wilson, L. J.

2013-04-01

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-μM 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.

Monitoring Ultrafast Chemical Dynamics by Time-Domain X-ray Photo- and Auger-Electron Spectroscopy.

PubMed

Gessner, Oliver; Gühr, Markus

2016-01-19

The directed flow of charge and energy is at the heart of all chemical processes. Extraordinary efforts are underway to monitor and understand the concerted motion of electrons and nuclei with ever increasing spatial and temporal sensitivity. The element specificity, chemical sensitivity, and temporal resolution of ultrafast X-ray spectroscopy techniques hold great promise to provide new insight into the fundamental interactions underlying chemical dynamics in systems ranging from isolated molecules to application-like devices. Here, we focus on the potential of ultrafast X-ray spectroscopy techniques based on the detection of photo- and Auger electrons to provide new fundamental insight into photochemical processes of systems with various degrees of complexity. Isolated nucleobases provide an excellent testing ground for our most fundamental understanding of intramolecular coupling between electrons and nuclei beyond the traditionally applied Born-Oppenheimer approximation. Ultrafast electronic relaxation dynamics enabled by the breakdown of this approximation is the major component of the nucleobase photoprotection mechanisms. Transient X-ray induced Auger electron spectroscopy on photoexcited thymine molecules provides atomic-site specific details of the extremely efficient coupling that converts potentially bond changing ultraviolet photon energy into benign heat. In particular, the time-dependent spectral shift of a specific Auger band is sensitive to the length of a single bond within the molecule. The X-ray induced Auger transients show evidence for an electronic transition out of the initially excited state within only ∼200 fs in contrast to theoretically predicted picosecond population trapping behind a reaction barrier. Photoinduced charge transfer dynamics between transition metal complexes and semiconductor nanostructures are of central importance for many emerging energy and climate relevant technologies. Numerous demonstrations of photovoltaic and

Electron Spectroscopy: Ultraviolet and X-Ray Excitation.

ERIC Educational Resources Information Center

Baker, A. D.; And Others

1980-01-01

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);…

X-ray Emission Line Spectroscopy of Nearby Galaxies

NASA Astrophysics Data System (ADS)

Wang, Daniel

What are the origins of the diffuse soft X-ray emission from non-AGN galaxies? Preliminary analysis of XMM-Newton RGS spectra shows that a substantial fraction of the emission cannot arise from optically-thin thermal plasma, as commonly assumed, and may originate in charge exchange at the interface with neutral gas. We request the support for a comprehensive observing, data analysis, and modeling program to spectroscopically determine the origins of the emission. First, we will use our scheduled XMM-Newton AO-10 368 ks observations of the nearest compact elliptical galaxy M32 to obtain the first spectroscopic calibration of the cumulative soft X-ray emission from the old stellar population and will develop a spectral model for the charge exchange, as well as analysis tools to measure the spatial and kinematic properties of the X-ray line- emitting plasma. Second, we will characterize the truly diffuse emission from the hot plasma and/or its interplay with the neutral gas in a sample of galactic spheroids and active star forming/starburst regions in nearby galaxies observed by XMM-Newton. In particular, we will map out the spatial distributions of key emission lines and measure (or tightly constrain) the kinematics of hot plasma outflows for a few X-ray-emitting regions with high-quality RGS data. For galaxies with insufficient counting statistics in individual emission lines, we will conduct a spectral stacking analysis to constrain the average properties of the X-ray-emitting plasma. We will use the results of these X-ray spectroscopic analyses, together with complementary X-ray CCD imaging/spectral data and observations in other wavelength bands, to test the models of the emission. In addition to the charge exchange, alternative scenarios such as resonance scattering and relic AGN photo-ionization will also be examined for suitable regions. These studies are important to the understanding of the relationship between the diffuse soft X-ray emission and various

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xin

1996-12-01

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). Themore » 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.« less

High Resolution, Non-Dispersive X-Ray Calorimeter Spectrometers on EBITs and Orbiting Observatories

NASA Technical Reports Server (NTRS)

Porter, Frederick S.

2010-01-01

X-ray spectroscopy is the primary tool for performing atomic physics with Electron beam ion trap (EBITs). X-ray instruments have generally fallen into two general categories, 1) dispersive instruments with very high spectral resolving powers but limited spectral range, limited count rates, and require an entrance slit, generally, for EBITs, defined by the electron beam itself, and 2) non-dispersive solid-state detectors with much lower spectral resolving powers but that have a broad dynamic range, high count rate ability and do not require a slit. Both of these approaches have compromises that limit the type and efficiency of measurements that can be performed. In 1984 NASA initiated a program to produce a non-dispersive instrument with high spectral resolving power for x-ray astrophysics based on the cryogenic x-ray calorimeter. This program produced the XRS non-dispersive spectrometers on the Astro-E, Astro-E2 (Suzaku) orbiting observatories, the SXS instrument on the Astro-H observatory, and the planned XMS instrument on the International X-ray Observatory. Complimenting these spaceflight programs, a permanent high-resolution x-ray calorimeter spectrometer, the XRS/EBIT, was installed on the LLNL EBIT in 2000. This unique instrument was upgraded to a spectral resolving power of 1000 at 6 keV in 2003 and replaced by a nearly autonomous production-class spectrometer, the EBIT Calorimeter Spectrometer (ECS), in 2007. The ECS spectrometer has a simultaneous bandpass from 0.07 to over 100 keV with a spectral resolving power of 1300 at 6 keV with unit quantum efficiency, and 1900 at 60 keV with a quantum efficiency of 30%. X-ray calorimeters are event based, single photon spectrometers with event time tagging to better than 10 us. We are currently developing a follow-on instrument based on a newer generation of x-ray calorimeters with a spectral resolving power of 3000 at 6 keV, and improved timing and measurement cadence. The unique capabilities of the x-ray

Frontiers of X-Ray Astronomy

NASA Astrophysics Data System (ADS)

Fabian, Andrew C.; Pounds, Kenneth A.; Blandford, Roger D.

2004-07-01

Preface; 1. Forty years on from Aerobee 150: a personal perspective K. Pounds; 2. X-ray spectroscopy of astrophysical plasmas S. M. Kahn, E. Behar, A. Kinkhabwala and D. W. Savin; 3. X-rays from stars M. Gudel; 4. X-ray observations of accreting white-dwarf systems M. Cropper, G. Ramsay, C. Hellier, K. Mukai, C. Mauche and D. Pandel; 5. Accretion flows in X-ray binaries C. Done; 6. Recent X-ray observations of supernova remnants C. R. Canizares; 7. Luminous X-ray sources in spiral and star-forming galaxies M. Ward; 8. Cosmological constraints from Chandra observations of galaxy clusters S. W. Allen; 9. Clusters of galaxies: a cosmological probe R. Mushotzky; 10. Obscured active galactic nuclei: the hidden side of the X-ray Universe G. Matt; 11. The Chandra Deep Field-North Survey and the cosmic X-ray background W. N. Brandt, D. M. Alexander, F. E. Bauer and A. E. Hornschemeier; 12. Hunting the first black holes G. Hasinger; 13. X-ray astronomy in the new millennium: a summary R. D. Blandford.

The Cambridge-Cambridge X-ray Serendipity Survey: I X-ray luminous galaxies

NASA Technical Reports Server (NTRS)

Boyle, B. J.; Mcmahon, R. G.; Wilkes, B. J.; Elvis, M.

1994-01-01

We report on the first results obtained from a new optical identification program of 123 faint X-ray sources with S(0.5-2 keV) greater than 2 x 10(exp -14) erg/s/sq cm serendipitously detected in ROSAT PSPC pointed observations. We have spectroscopically identified the optical counterparts to more than 100 sources in this survey. Although the majority of the sample (68 objects) are QSO's, we have also identified 12 narrow emission line galaxies which have extreme X-ray luminosities (10(exp 42) less than L(sub X) less than 10(exp 43.5) erg/s). Subsequent spectroscopy reveals them to be a mixture of star-burst galaxies and Seyfert 2 galaxies in approximately equal numbers. Combined with potentially similar objects identified in the Einstein Extended Medium Sensitivity Survey, these X-ray luminous galaxies exhibit a rate of cosmological evolution, L(sub X) varies as (1 + z)(exp 2.5 +/- 1.0), consistent with that derived for X-ray QSO's. This evolution, coupled with the steep slope determined for the faint end of the X-ray luminosity function (Phi(L(sub X)) varies as L(sub X)(exp -1.9)), implies that such objects could comprise 15-35% of the soft (1-2 keV) X-ray background.

Lu.sub.1-xI.sub.3:Ce.sub.x-a scintillator for gamma-ray spectroscopy and time-of-flight pet

DOEpatents

Shah, Kanai S [Newton, MA

2008-02-12

The present invention includes very fast scintillator materials including lutetium iodide doped with Cerium (Lu.sub.1-xI.sub.3:Ce.sub.x; LuI.sub.3:Ce). The LuI.sub.3 scintillator material has surprisingly good characteristics including high light output, high gamma-ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow that the material is useful for gamma-ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration.

Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

DOE PAGES

Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; ...

2015-11-27

In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shotmore » based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.« less

Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech

In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shotmore » based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.« less

Ultrafast Absorption Spectroscopy of Aluminum Plasmas Created by LCLS using Betatron X-Ray Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albert, Felicie

2016-10-12

This document summarizes the goals and accomplishments of a six month-long LDRD project, awarded through the LLNL director Early and Mid Career Recognition (EMCR) program. This project allowed us to support beamtime awarded at the Matter under Extreme Conditions (MEC) end station of the Linac Coherent Light Source (LCLS). The goal of the experiment was to heat metallic samples with the bright x-rays from the LCLS free electron laser. Then, we studied how they relaxed back to equilibrium by probing them with ultrafast x-ray absorption spectroscopy using laser-based betatron radiation. Our work enabled large collaborations between LLNL, SLAC, LBNL, andmore » institutions in France and in the UK, while providing training to undergraduate and graduate students during the experiment. Following this LDRD project, the PI was awarded a 5-year DOE early career research grant to further develop applications of laser-driven x-ray sources for high energy density science experiments and warm dense matter states.« less

X-ray Raman spectroscopy of lithium-ion battery electrolyte solutions in a flow cell.

PubMed

Ketenoglu, Didem; Spiekermann, Georg; Harder, Manuel; Oz, Erdinc; Koz, Cevriye; Yagci, Mehmet C; Yilmaz, Eda; Yin, Zhong; Sahle, Christoph J; Detlefs, Blanka; Yavaş, Hasan

2018-03-01

The effects of varying LiPF 6 salt concentration and the presence of lithium bis(oxalate)borate additive on the electronic structure of commonly used lithium-ion battery electrolyte solvents (ethylene carbonate-dimethyl carbonate and propylene carbonate) have been investigated. X-ray Raman scattering spectroscopy (a non-resonant inelastic X-ray scattering method) was utilized together with a closed-circle flow cell. Carbon and oxygen K-edges provide characteristic information on the electronic structure of the electrolyte solutions, which are sensitive to local chemistry. Higher Li + ion concentration in the solvent manifests itself as a blue-shift of both the π* feature in the carbon edge and the carbonyl π* feature in the oxygen edge. While these oxygen K-edge results agree with previous soft X-ray absorption studies on LiBF 4 salt concentration in propylene carbonate, carbon K-edge spectra reveal a shift in energy, which can be explained with differing ionic conductivities of the electrolyte solutions.

Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

NASA Astrophysics Data System (ADS)

Gaudin, J.; Fourment, C.; Cho, B. I.; Engelhorn, K.; Galtier, E.; Harmand, M.; Leguay, P. M.; Lee, H. J.; Nagler, B.; Nakatsutsumi, M.; Ozkan, C.; Störmer, M.; Toleikis, S.; Tschentscher, Th; Heimann, P. A.; Dorchies, F.

2014-04-01

The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called ``molecular movie'' within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level of the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes.

The characterization of Cr secondary oxide phases in ZnO films studied by X-ray spectroscopy and photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Chiou, J. W.; Chang, S. Y.; Huang, W. H.; Chen, Y. T.; Hsu, C. W.; Hu, Y. M.; Chen, J. M.; Chen, C.-H.; Kumar, K.; Guo, J.-H.

2011-03-01

X-ray absorption near-edge structure (XANES), X-ray emission spectroscopy (XES), and X-ray photoemission spectroscopy (XPS) were used to characterize the Cr secondary oxide phases in ZnO films that had been prepared using a co-sputtering method. Analysis of the Cr L3,2-edge XANES spectra reveals that the intensity of white-line features decreases subtly as the sputtering power increases, indicating that the occupation of Cr 3 d orbitals increases with Cr concentration in (Zn, Cr)O films. The O K-edge spectra show that the intensity of XANES features of (Zn, Cr)O films is lower than those of ZnO film, suggesting enhanced occupation of O 2 p-derived states through O 2 p-Cr 3 d hybridization. The XES and XPS spectra indicate that the line shapes in the valence band of (Zn, Cr)O films are quite different from those of ZnO and that the Cr 2O 3 phase dominates the spinel structure of (Zn, Cr)O films increasingly as the Cr sputtering power is increased. Over all results suggest that the non-ferromagnetic behavior of (Zn, Cr)O films can be attributed to the dominant presence of Cr 2O 3, whereas the bulk comprise phase segregations of Cr 2O 3 and/or ZnCr 2O 4, which results them the most stable TM-doped ZnO material against etching.

Remote X-Ray Diffraction and X-Ray Fluorescence Analysis on Planetary Surfaces

NASA Technical Reports Server (NTRS)

Blake, David F.; DeVincenzi, D. (Technical Monitor)

1999-01-01

The legacy of planetary X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) began in 1960 when W. Parish proposed an XRD instrument for deployment on the moon. The instrument was built and flight qualified, but the Lunar XRD program was cancelled shortly before the first human landing in 1969. XRF chemical data have been collected in situ by surface landers on Mars (Viking 1 & 2, Pathfinder) and Venus (Venera 13 & 14). These highly successful experiments provide critical constraints on our current understanding of surface processes and planetary evolution. However, the mineralogy, which is more critical to planetary surface science than simple chemical analysis, will remain unknown or will at best be imprecisely constrained until X-ray diffraction (XRD) data are collected. Recent progress in X-ray detector technology allows the consideration of simultaneous XRD (mineralogic analysis) and high-precision XRF (elemental analysis) in systems miniaturized to the point where they can be mounted on fixed landers or small robotic rovers. There is a variety of potential targets for XRD/XRF equipped landers within the solar system, the most compelling of which are the poles of the moon, the southern highlands of Mars and Europa.

Preliminary designs for X-ray source modifications for the Marshall Space Flight Center's X-ray calibration facility

NASA Technical Reports Server (NTRS)

Croft, W. L.

1986-01-01

The objective of this investigation is to develop preliminary designs for modifications to the X-ray source of the MSFC X-Ray Calibration Facility. Recommendations are made regarding: (1) the production of an unpolarized X-ray beam, (2) modification of the source to provide characteristic X-rays with energies up to 40 keV, and (3) addition of the capability to calibrate instruments in the extreme ultraviolet wavelength region.

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

PubMed Central

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.

2010-01-01

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° 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/ΔE 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 × 1013 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 µm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/ΔE > 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

Characterization of the LCLS “nanosecond two-bunch” mode for x-ray speckle visibility spectroscopy experiments

DOE PAGES

Sun, Yanwen; Zhu, Diling; Song, Sanghoon; ...

2017-05-23

The generation of two X-ray pulses with tunable nanosecond scale time separations has recently been demonstrated at the Linac Coherent Light Source using an accelerator based technique. This approach offers the opportunity to extend X-ray Photon Correlation Spectroscopy techniques to the yet unexplored regime of nanosecond timescales by means of X-ray Speckle Visibility Spectroscopy. As the two pulses originate from two independent Spontaneous Amplified Stimulated Emission processes, the beam properties fluctuate from pulse pair to pulse pair, but as well between the individual pulses within a pair. However, two-pulse XSVS experiments require the intensity of the individual pulses to bemore » either identical in the ideal case, or with a accurately known intensity ratio. We present the design and performances of a non-destructive intensity diagnostic based on measurement of scattering from a transparent target using a high-speed photo-detector. Individual pulses within a pulse pair with time delays as short as 0.7 ns can be resolved. Moreover, using small angle coherent scattering, we characterize the averaged spatial overlap of the focused pulse pairs. Furthermore, the multi-shot average-speckle contrasts from individual pulses and pulse pairs are compared.« less

SphinX: The Solar Photometer in X-Rays

NASA Astrophysics Data System (ADS)

Gburek, Szymon; Sylwester, Janusz; Kowalinski, Miroslaw; Bakala, Jaroslaw; Kordylewski, Zbigniew; Podgorski, Piotr; Plocieniak, Stefan; Siarkowski, Marek; Sylwester, Barbara; Trzebinski, Witold; Kuzin, Sergey V.; Pertsov, Andrey A.; Kotov, Yurij D.; Farnik, Frantisek; Reale, Fabio; Phillips, Kenneth J. H.

2013-04-01

Solar Photometer in X-rays (SphinX) was a spectrophotometer developed to observe the Sun in soft X-rays. The instrument observed in the energy range ≈ 1 - 15 keV with resolution ≈ 0.4 keV. SphinX was flown on the Russian CORONAS-PHOTON satellite placed inside the TESIS EUV and X telescope assembly. The spacecraft launch took place on 30 January 2009 at 13:30 UT at the Plesetsk Cosmodrome in Russia. The SphinX experiment mission began a couple of weeks later on 20 February 2009 when the first telemetry dumps were received. The mission ended nine months later on 29 November 2009 when data transmission was terminated. SphinX provided an excellent set of observations during very low solar activity. This was indeed the period in which solar activity dropped to the lowest level observed in X-rays ever. The SphinX instrument design, construction, and operation principle are described. Information on SphinX data repositories, dissemination methods, format, and calibration is given together with general recommendations for data users. Scientific research areas in which SphinX data find application are reviewed.

X-ray photoelectron spectroscopy and atomic force microscopy characterization of the effects of etching Zn xCd 1- xTe surfaces

NASA Astrophysics Data System (ADS)

George, M. A.; Azoulay, M.; Jayatirtha, H. N.; Burger, A.; Collins, W. E.; Silberman, E.

1993-10-01

X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) was used for the first time to characterize the chemical composition of modified surfaces of Zn xCd 1- xTe single crystals. These surface treatments were selected for their relevance to device preparation procedures. The XPS peaks indicated an increase of the tellurium and a depletion of the cadmium concentrations upon etching in bromine methanol solution. AFM revealed the formation of pronounced Te inclusions. Higher x values correlated with a decrease in residual bromine left on the surface, while cut and polished samples had higher oxide concentrations and increased bromination of the surface than cleaved samples.

Broadband high resolution X-ray spectral analyzer

DOEpatents

Silver, Eric H.; Legros, Mark; Madden, Norm W.; Goulding, Fred; Landis, Don

1998-01-01

A broad bandwidth high resolution x-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces x-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available x-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for x-ray microanalysis or in research applications such as laboratory and astrophysical x-ray and particle spectroscopy.

Broadband high resolution X-ray spectral analyzer

DOEpatents

Silver, E.H.; Legros, M.; Madden, N.W.; Goulding, F.; Landis, D.

1998-07-07

A broad bandwidth high resolution X-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces X-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available X-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for X-ray microanalysis or in research applications such as laboratory and astrophysical X-ray and particle spectroscopy. 6 figs.

Simulations of ultrafast x-ray laser experiments

NASA Astrophysics Data System (ADS)

Fortmann-Grote, C.; Andreev, A. A.; Appel, K.; Branco, J.; Briggs, R.; Bussmann, M.; Buzmakov, A.; Garten, M.; Grund, A.; Huebl, A.; Jurek, Z.; Loh, N. D.; Nakatsutsumi, M.; Samoylova, L.; Santra, R.; Schneidmiller, E. A.; Sharma, A.; Steiniger, K.; Yakubov, S.; Yoon, C. H.; Yurkov, M. V.; Zastrau, U.; Ziaja-Motyka, B.; Mancuso, A. P.

2017-06-01

Simulations of experiments at modern light sources, such as optical laser laboratories, synchrotrons, and free electron lasers, become increasingly important for the successful preparation, execution, and analysis of these experiments investigating ever more complex physical systems, e.g. biomolecules, complex materials, and ultra-short lived states of matter at extreme conditions. We have implemented a platform for complete start-to-end simulations of various types of photon science experiments, tracking the radiation from the source through the beam transport optics to the sample or target under investigation, its interaction with and scattering from the sample, and registration in a photon detector. This tool allows researchers and facility operators to simulate their experiments and instruments under real life conditions, identify promising and unattainable regions of the parameter space and ultimately make better use of valuable beamtime. In this paper, we present an overview about status and future development of the simulation platform and discuss three applications: 1.) Single-particle imaging of biomolecules using x-ray free electron lasers and optimization of x-ray pulse properties, 2.) x-ray scattering diagnostics of hot dense plasmas in high power laser-matter interaction and identification of plasma instabilities, and 3.) x-ray absorption spectroscopy in warm dense matter created by high energy laser-matter interaction and pulse shape optimization for low-isentrope dynamic compression.

X-ray magnetic circular dichroism measured at the Fe K-edge with a reduced intrinsic broadening: x-ray absorption spectroscopy versus resonant inelastic x-ray scattering measurements

NASA Astrophysics Data System (ADS)

Juhin, Amélie; Sainctavit, Philippe; Ollefs, Katharina; Sikora, Marcin; Filipponi, Adriano; Glatzel, Pieter; Wilhelm, Fabrice; Rogalev, Andrei

2016-12-01

X-ray magnetic circular dichroism is measured at the Fe K pre-edge in yttrium iron garnet using two different procedures that allow reducing the intrinsic broadening due to the 1s corehole lifetime. First, deconvolution of XMCD data measured in total fluorescence yield (TFY) with an extremely high signal-to-noise ratio enables a factor of 2.4 to be gained in the XMCD intensity. Ligand field multiplet calculations performed with different values of intrinsic broadening show that deconvolving such high quality XMCD data is similar to reducing the lifetime broadening from a 1s corehole to a 2p corehole. Second, MCD is measured by resonant inelastic x-ray scattering spectroscopy as a function of incident energy and emission energy. Selection of a fixed emission energy, instead of using the TFY, allows enhancing the MCD intensity up to a factor of  ˜4.7. However, this significantly changes the spectral shape of the XMCD signal, which cannot be interpreted any more as an absorption spectrum.

A study of mercuric iodide near melting using differential scanning calorimetry, Raman spectroscopy and X-ray diffraction

NASA Astrophysics Data System (ADS)

Burger, A.; Morgan, S.; Jiang, H.; Silberman, E.; Schieber, M.; Van Den Berg, L.; Keller, L.; Wagner, C. N. J.

1989-11-01

High-temperature studies of mercuric iodide (HgI2) involving differential scanning calorimetry (DSC), Raman spectroscopy and X-ray powder diffraction have failed to confirm the existence of a red-colored tetragonal high-temperature phase called α'-HgI2 reported by S.N. Toubektsis et al. [J. Appl. Phys. 58 (1988) 2070] using DSC measurements. The multiple DSC peaks near melting reported by Toubektsis are found by the present authors only if the sample is heated in a stainless-steel container. Using a Pyrex container or inserting a platinum foil between the HgI2 and the stainless-steel container yields only one sharp, single DSC peak at the melting point. The nonexistence of the α' phase is confirmed by high-temperature X-ray diffraction and Raman spectroscopy performed in the vicinity of the melting point. These methods clearly, indicate the existence of only the yellow orthorhombic β-HgI2 phase. The experimental high-temperature DSC, Raman and X-ray diffraction data are presented and discussed.

Prospect of space-based interferometry at EUV and soft X-ray wavelengths

NASA Technical Reports Server (NTRS)

Welsh, Barry Y.; Chakrabarti, Supriya

1992-01-01

We review the current capabilities of high-resolution, spectroscopic, space-borne instrumentation available for both solar and stellar observations in the EUV and soft X-ray wavelength regimes, and describe the basic design of a compact, all-reflection interferometer based on the spatial heterodyne technique; this is capable of producing a resolving power (lambda/Delta-lambda) of about 20,000 in the 100-200 A region using presently available multilayer optical components. Such an instrument can be readily constructed with existing technology. Due to its small size and lack of moving parts, it is ideally suited to spaceborne applications. Based on best estimates of the efficiency of this instrument at soft X-ray wavelengths, we review the possible use of this high-resolution interferometer in obtaining high-resolution full-disk spectroscopy of the sun. We also discuss its possible use for observations of diffuse sources such as the EUV interstellar background radiation.

Analysis of small-angle X-ray scattering data in the presence of significant instrumental smearing

PubMed Central

Bergenholtz, Johan; Ulama, Jeanette; Zackrisson Oskolkova, Malin

2016-01-01

A laboratory-scale small-angle X-ray scattering instrument with pinhole collimation has been used to assess smearing effects due to instrumental resolution. A new, numerically efficient method to smear ideal model intensities is developed and presented. It allows for directly using measured profiles of isotropic but otherwise arbitrary beams in smearing calculations. Samples of low-polydispersity polymer spheres have been used to show that scattering data can in this way be quantitatively modeled even when there is substantial distortion due to instrumental resolution. PMID:26937235

Applications of phase-contrast x-ray imaging to medicine using an x-ray interferometer

NASA Astrophysics Data System (ADS)

Momose, Atsushi; Yoneyama, Akio; Takeda, Tohoru; Itai, Yuji; Tu, Jinhong; Hirano, Keiichi

1999-10-01

We are investigating possible medical applications of phase- contrast X-ray imaging using an X-ray interferometer. This paper introduces the strategy of the research project and the present status. The main subject is to broaden the observation area to enable in vivo observation. For this purpose, large X-ray interferometers were developed, and 2.5 cm X 1.5 cm interference patterns were generated using synchrotron X-rays. An improvement of the spatial resolution is also included in the project, and an X-ray interferometer designed for high-resolution phase-contrast X-ray imaging was fabricated and tested. In parallel with the instrumental developments, various soft tissues are observed by phase- contrast X-ray CT to find correspondence between the generated contrast and our histological knowledge. The observation done so far suggests that cancerous tissues are differentiated from normal tissues and that blood can produce phase contrast. Furthermore, this project includes exploring materials that modulate phase contrast for selective imaging.

Saccharose solid matrix embedded proteins: a new method for sample preparation for X-ray absorption spectroscopy.

PubMed

Ascone, I; Sabatucci, A; Bubacco, L; Di Muro, P; Salvato, B

2000-01-01

In this study, solid samples of hemoglobin and hemocyanin have been prepared by embedding the proteins into a saccharose-based matrix. These materials have been developed specifically for specimens for X-ray absorption spectroscopy (XAS). The preservation of protein conformation and active site organization was tested, making comparisons between the solid and the corresponding liquid samples, using resonance Raman, infra red, fluorescence and XAS. The XAS spectra of irradiated solid and liquid samples were then compared, and the preservation of biological activity of the proteins during both preparation procedure and X-ray irradiation was assessed. In all cases, the measurements clearly demonstrate that protein solid samples are both structurally and functionally quite well preserved, much better than those in the liquid state. The saccharose matrix provides an excellent protection against X-ray damages, allowing for longer exposure to the X-ray beam. Moreover, the demonstrated long-term stability of samples permits their preparation and storage in optimal conditions, allowing for the repetition of data collection with the same sample in several experimental sessions. The very high protein concentration that can be reached results in a significantly better signal-to-noise ratio, particularly useful for high molecular weight proteins with a low metal-to-protein ratio. On the bases of the above-mentioned results, we propose the new method as a standard procedure for the preparation of biological samples to be used for XAS spectroscopy.

Adaptive design of an X-ray magnetic circular dichroism spectroscopy experiment with Gaussian process modelling

NASA Astrophysics Data System (ADS)

Ueno, Tetsuro; Hino, Hideitsu; Hashimoto, Ai; Takeichi, Yasuo; Sawada, Masahiro; Ono, Kanta

2018-01-01

Spectroscopy is a widely used experimental technique, and enhancing its efficiency can have a strong impact on materials research. We propose an adaptive design for spectroscopy experiments that uses a machine learning technique to improve efficiency. We examined X-ray magnetic circular dichroism (XMCD) spectroscopy for the applicability of a machine learning technique to spectroscopy. An XMCD spectrum was predicted by Gaussian process modelling with learning of an experimental spectrum using a limited number of observed data points. Adaptive sampling of data points with maximum variance of the predicted spectrum successfully reduced the total data points for the evaluation of magnetic moments while providing the required accuracy. The present method reduces the time and cost for XMCD spectroscopy and has potential applicability to various spectroscopies.

Super DIOS: Future X-ray Spectroscopic Mission to Search for Dark Baryons

NASA Astrophysics Data System (ADS)

Yamada, S.; Ohashi, T.; Ishisaki, Y.; Ezoe, Y.; Ichinohe, Y.; Kitazawa, S.; Kosaka, K.; Hayakawa, R.; Nunomura, K.; Mitsuda, K.; Yamasaki, N. Y.; Kikuchi, T.; Hayashi, T.; Muramatsu, H.; Nakashima, Y.; Tawara, Y.; Mitsuishi, I.; Babazaki, Y.; Seki, D.; Otsuka, K.; Ishihara, M.; Osato, K.; Ota, N.; Tomariguchi, M.; Nagai, D.; Lau, E.; Sato, K.

2018-04-01

The updated program of the future Japanese X-ray satellite mission Diffuse Intergalactic Oxygen Surveyor (DIOS), called as Super DIOS, is planned to search for dark baryons in the form of warm-hot intergalactic medium (WHIM) with high-resolution X-ray spectroscopy. The mission will detect redshifted emission lines from OVII, OVIII and other ions, leading to an overall understanding of the physical nature and spatial distribution of dark baryons as a function of cosmological timescale. We have started the conceptual design of the satellite and onboard instruments, focusing on the era of 2030s. The major change will be an improved angular resolution of the X-ray telescope. Super DIOS will have a 10-arcsec resolution, which is an improvement by a factor of about 20 over DIOS. With this resolution, most of the contaminating X-ray sources will be separated, and the level of the diffuse X-ray background will be much reduced after subtraction of point sources. This will give us higher sensitivity to map out the WHIM in emission.

X-ray luminescence computed tomography using a focused x-ray beam.

PubMed

Zhang, Wei; Lun, Michael C; Nguyen, Alex Anh-Tu; Li, Changqing

2017-11-01

Due to the low x-ray photon utilization efficiency and low measurement sensitivity of the electron multiplying charge coupled device camera setup, the collimator-based narrow beam x-ray luminescence computed tomography (XLCT) usually requires a long measurement time. We, for the first time, report a focused x-ray beam-based XLCT imaging system with measurements by a single optical fiber bundle and a photomultiplier tube (PMT). An x-ray tube with a polycapillary lens was used to generate a focused x-ray beam whose x-ray photon density is 1200 times larger than a collimated x-ray beam. An optical fiber bundle was employed to collect and deliver the emitted photons on the phantom surface to the PMT. The total measurement time was reduced to 12.5 min. For numerical simulations of both single and six fiber bundle cases, we were able to reconstruct six targets successfully. For the phantom experiment, two targets with an edge-to-edge distance of 0.4 mm and a center-to-center distance of 0.8 mm were successfully reconstructed by the measurement setup with a single fiber bundle and a PMT. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

History of Chandra X-Ray Observatory

NASA Image and Video Library

1998-01-01

This is a computer rendering of the fully developed Chandra X-Ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF). In 1999, the AXAF was renamed the CXO in honor of the late Indian-American Novel Laureate Subrahmanyan Chandrasekhar. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It is designed to observe x-rays from high energy regions of the Universe, such as hot gas in the renmants of exploded stars. It produces picture-like images of x-ray emissions analogous to those made in visible light, as well as gathers data on the chemical composition of x-ray radiating objects. The CXO helps astronomers world-wide better understand the structure and evolution of the universe by studying powerful sources of x-ray such as exploding stars, matter falling into black holes, and other exotic celestial objects. The Observatory has three major parts: (1) the x-ray telescope, whose mirrors will focus x-rays from celestial objects; (2) the science instruments that record the x-rays so that x-ray images can be produced and analyzed; and (3) the spacecraft, which provides the environment necessary for the telescope and the instruments to work. TRW, Inc. was the prime contractor for the development of the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission. (Image courtesy of TRW).

Normal incidence X-ray mirror for chemical microanalysis

DOEpatents

Carr, Martin J.; Romig, Jr., Alton D.

1990-01-01

A non-planar, focusing mirror, to be utilized in both electron column instruments and micro-x-ray fluorescence instruments for performing chemical microanalysis on a sample, comprises a concave, generally spherical base substrate and a predetermined number of alternating layers of high atomic number material and low atomic number material contiguously formed on the base substrate. The thickness of each layer is an integral multiple of the wavelength being reflected and may vary non-uniformly according to a predetermined design. The chemical analytical instruments in which the mirror is used also include a predetermined energy source for directing energy onto the sample and a detector for receiving and detecting the x-rays emitted from the sample; the non-planar mirror is located between the sample and detector and collects the x-rays emitted from the sample at a large solid angle and focuses the collected x-rays to the sample. For electron column instruments, the wavelengths of interest lie above 1.5 nm, while for x-ray fluorescence instruments, the range of interest is below 0.2 nm. Also, x-ray fluorescence instruments include an additional non-planar focusing mirror, formed in the same manner as the previously described m The invention described herein was made in the performance of work under contract with the Department of Energy, Contract No. DE-AC04-76DP00789, and the United States Government has rights in the invention pursuant to this contract.

Summary: Update to ASTM Guide E 1523 to Charge Control and Charge Referencing Techniques in X-ray Photoelectron Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, Donald R.

2005-04-22

An updated version of the ASTM guide E1523 to the methods to charge control and charge referencing techniques in x-ray photoelectron spectroscopy has been released by ASTM. The guide is meant to acquaint x-ray photoelectron spectroscopy (XPS) users with the various charge control and charge referencing techniques that are and have been used in the acquisition and interpretation of XPS data from surfaces of insulating specimens. The current guide has been expanded to include new references as well as recommendations for reporting information on charge control and charge referencing. The previous version of the document had been published in 1997.

Sulfur Speciation in Biochars by Very High Resolution Benchtop Ka X-Ray Emission Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheah, Singfoong; Holden, William M.; Seidler, Gerald T.

The analytical chemistry of sulfur-containing materials poses substantial technical challenges, especially due to the limitations of 33S NMR and the time-intensive preparations required for wet-chemistry analyses. A number of prior studies have found that synchrotron-based X-ray absorption near edge structure (XANES) measurements can give detailed speciation of sulfur chemistry in such cases. However, due to the obvious access limitations, synchrotron XANES of sulfur cannot be part of routine analytical practice across the chemical sciences community. Here, in a study of the sulfur chemistry in biochars, we compare and contrast the chemical inferences available from synchrotron XANES with that given bymore » benchtop, extremely high resolution wavelength-dispersive X-ray fluorescence (WD-XRF) spectroscopy, also often called X-ray emission spectroscopy (XES). While the XANES spectra have higher total information content, often giving differentiation between different moieties having the same oxidation state, the lower sensitivity of the S Ka XES to coordination and local structure provides pragmatic benefit for the more limited goal of quantifying the S oxidation state distribution. Within that constrained metric, we find good agreement between the two methods. As the sulfur concentrations were as low as 150 ppm, these measurements provide proof-of-principle for characterization of the sulfur chemistry of biochars and potential applications to other areas such as soils, batteries, catalysts, and fossil fuels and their combustion products.« less

Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

PubMed Central

Gaudin, J.; Fourment, C.; Cho, B. I.; Engelhorn, K.; Galtier, E.; Harmand, M.; Leguay, P. M.; Lee, H. J.; Nagler, B.; Nakatsutsumi, M.; Ozkan, C.; Störmer, M.; Toleikis, S.; Tschentscher, Th; Heimann, P. A.; Dorchies, F.

2014-01-01

The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called “molecular movie” within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level of the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes. PMID:24740172

Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

DOE PAGES

Gaudin, J.; Fourment, C.; Cho, B. I.; ...

2014-04-17

The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called “molecular movie” within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level ofmore » the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes.« less

Effect of Pressure on Valence and Structural Properties of YbFe 2 Ge 2 Heavy Fermion Compound—A Combined Inelastic X-ray Spectroscopy, X-ray Diffraction, and Theoretical Investigation

DOE PAGES

Kumar, Ravhi S.; Svane, Axel; Vaitheeswaran, Ganapathy; ...

2015-10-19

We measured the crystal structure and the Yb valence of the YbFe 2Ge 2 heavy fermion compound at room temperature and under high pressures using high-pressure powder X-ray diffraction and X-ray absorption spectroscopy via both partial fluorescence yield and resonant inelastic X-ray emission techniques. Moreover, the measurements are complemented by first-principles density functional theoretical calculations using the self-interaction corrected local spin density approximation investigating in particular the magnetic structure and the Yb valence. Finally, while the ThCr 2Si 2-type tetragonal (I4/mmm) structure is stable up to 53 GPa, the X-ray emission results show an increase of the Yb valence frommore » v = 2.72(2) at ambient pressure to v = 2.93(3) at ~9 GPa, where at low temperature a pressure-induced quantum critical state was reported.« less

Composition of RF-sputtered refractory compounds determined by X-ray photoelectron spectroscopy

NASA Technical Reports Server (NTRS)

Wheeler, D. R.; Brainard, W. A.

1978-01-01

RF-sputtered coatings of CrB2, MoSi2, Mo2C, TiC, and MoS2 were examined by X-ray photoelectron spectroscopy (XPS). Data on stoichiometry, impurity content, and chemical bonding were obtained. The influences of sputtering target history, deposition time, RF power level, and substrate bias were studied. Significant deviations from stoichiometry and high oxide levels were related to target outgassing. The effect of substrate bias depended on the particular coating material studied.

Soft x-ray transmission grating spectrometer for X-ray Surveyor and smaller missions with high resolving power

NASA Astrophysics Data System (ADS)

Heilmann, Ralf K.; Bruccoleri, Alexander; Schattenburg, Mark; Kolodziejczak, jeffery; Gaskin, Jessica; O'Dell, Stephen L.

2017-01-01

with the most advanced grating spectrometer instrument designs for future soft x-ray spectroscopy missions. We will review the most recent CAT grating fabrication and x-ray test results.

Microcalorimeters for High Resolution X-Ray Spectroscopy of Laboratory and Astrophysical Plasmas

NASA Technical Reports Server (NTRS)

Silver, E.; Flowers, Bobby J. (Technical Monitor)

2003-01-01

The proposal has three major objectives. The first focuses on advanced neutron-transmutation-doped (NTD)-based microcalorimeter development. Our goal is to develop an array of microcalorimeters with sub- 5 eV energy resolution that can operate with pile-up-free throughput of at least 100 Hz per pixel. The second objective is to establish our microcalorimeter as an essential x-ray diagnostic for laboratory astrophysics studies. We propose to develop a dedicated microcalorimeter spectrometer for the EBIT (electron beam ion trap). This instrument will incorporate the latest detector and cryogenic technology that we have available. The third objective is to investigate innovative ideas related to possible flight opportunities. These include compact, long lived cryo-systems, ultra-low temperature cold stages, low mass and low power electronics, and novel assemblies of thin windows with high x-ray transmission.

The ASTRO-H X-ray Observatory

NASA Astrophysics Data System (ADS)

Takahashi, Tadayuki; Mitsuda, Kazuhisa; Kelley, Richard; Aarts, Henri; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steve; Anabuki, Naohisa; Angelini, Lorella; Arnaud, Keith; Asai, Makoto; Audard, Marc; Awaki, Hisamitsu; Azzarello, Philipp; Baluta, Chris; Bamba, Aya; Bando, Nobutaka; Bautz, Mark; Blandford, Roger; Boyce, Kevin; Brown, Greg; Cackett, Ed; Chernyakova, Mara; Coppi, Paolo; Costantini, Elisa; de Plaa, Jelle; den Herder, Jan-Willem; DiPirro, Michael; Done, Chris; Dotani, Tadayasu; Doty, John; Ebisawa, Ken; Eckart, Megan; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew; Ferrigno, Carlo; Foster, Adam; Fujimoto, Ryuichi; Fukazawa, Yasushi; Funk, Stefan; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi; Gandhi, Poshak; Gendreau, Keith; Gilmore, Kirk; Haas, Daniel; Haba, Yoshito; Hamaguchi, Kenji; Hatsukade, Isamu; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko; Hirose, Kazuyuki; Hornschemeier, Ann; Hoshino, Akio; Hughes, John; Hwang, Una; Iizuka, Ryo; Inoue, Yoshiyuki; Ishibashi, Kazunori; Ishida, Manabu; Ishimura, Kosei; Ishisaki, Yoshitaka; Ito, Masayuki; Iwata, Naoko; Iyomoto, Naoko; Kaastra, Jelle; Kallman, Timothy; Kamae, Tuneyoshi; Kataoka, Jun; Katsuda, Satoru; Kawahara, Hajime; Kawaharada, Madoka; Kawai, Nobuyuki; Kawasaki, Shigeo; Khangaluyan, Dmitry; Kilbourne, Caroline; Kimura, Masashi; Kinugasa, Kenzo; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Kosaka, Tatsuro; Koujelev, Alex; Koyama, Katsuji; Krimm, Hans; Kubota, Aya; Kunieda, Hideyo; LaMassa, Stephanie; Laurent, Philippe; Lebrun, Francois; Leutenegger, Maurice; Limousin, Olivier; Loewenstein, Michael; Long, Knox; Lumb, David; Madejski, Grzegorz; Maeda, Yoshitomo; Makishima, Kazuo; Marchand, Genevieve; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian; Miller, Jon; Miller, Eric; Mineshige, Shin; Minesugi, Kenji; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Mukai, Koji; Murakami, Toshio; Murakami, Hiroshi; Mushotzky, Richard; Nagano, Hosei; Nagino, Ryo; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakazawa, Kazuhiro; Namba, Yoshiharu; Natsukari, Chikara; Nishioka, Yusuke; Nobukawa, Masayoshi; Nomachi, Masaharu; O'Dell, Steve; Odaka, Hirokazu; Ogawa, Hiroyuki; Ogawa, Mina; Ogi, Keiji; Ohashi, Takaya; Ohno, Masanori; Ohta, Masayuki; Okajima, Takashi; Okamoto, Atsushi; Okazaki, Tsuyoshi; Ota, Naomi; Ozaki, Masanobu; Paerels, Fritzs; Paltani, Stéphane; Parmar, Arvind; Petre, Robert; Pohl, Martin; Porter, F. Scott; Ramsey, Brian; Reis, Rubens; Reynolds, Christopher; Russell, Helen; Safi-Harb, Samar; Sakai, Shin-ichiro; Sameshima, Hiroaki; Sanders, Jeremy; Sato, Goro; Sato, Rie; Sato, Yohichi; Sato, Kosuke; Sawada, Makoto; Serlemitsos, Peter; Seta, Hiromi; Shibano, Yasuko; Shida, Maki; Shimada, Takanobu; Shinozaki, Keisuke; Shirron, Peter; Simionescu, Aurora; Simmons, Cynthia; Smith, Randall; Sneiderman, Gary; Soong, Yang; Stawarz, Lukasz; Sugawara, Yasuharu; Sugita, Hiroyuki; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takeda, Shin-ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Takayuki; Tamura, Keisuke; Tanaka, Takaaki; Tanaka, Yasuo; Tashiro, Makoto; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi; Uchida, Hiroyuki; Uchiyama, Yasunobu; Uchiyama, Hideki; Ueda, Yoshihiro; Ueno, Shiro; Uno, Shinichiro; Urry, Meg; Ursino, Eugenio; de Vries, Cor; Wada, Atsushi; Watanabe, Shin; Werner, Norbert; White, Nicholas; Yamada, Takahiro; Yamada, Shinya; Yamaguchi, Hiroya; Yamasaki, Noriko; Yamauchi, Shigeo; Yamauchi, Makoto; Yatsu, Yoichi; Yonetoku, Daisuke; Yoshida, Atsumasa; Yuasa, Takayuki

2012-09-01

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the highenergy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-12 keV with high spectral resolution of ΔE ≦ 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.

High-pressure studies with x-rays using diamond anvil cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Guoyin; Mao, Ho Kwang

2016-11-22

Pressure profoundly alters all states of matter. The symbiotic development of ultrahigh-pressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. Thesemore » HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and

High-pressure studies with x-rays using diamond anvil cells

NASA Astrophysics Data System (ADS)

Shen, Guoyin; Mao, Ho Kwang

2017-01-01

Pressure profoundly alters all states of matter. The symbiotic development of ultrahigh-pressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials’ properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and

Unveiling the nature of INTEGRAL objects through optical spectroscopy. IX. Twenty two more identifications, and a glance into the far hard X-ray Universe

NASA Astrophysics Data System (ADS)

Masetti, N.; Parisi, P.; Jiménez-Bailón, E.; Palazzi, E.; Chavushyan, V.; Bassani, L.; Bazzano, A.; Bird, A. J.; Dean, A. J.; Galaz, G.; Landi, R.; Malizia, A.; Minniti, D.; Morelli, L.; Schiavone, F.; Stephen, J. B.; Ubertini, P.

2012-02-01

Since its launch in October 2002, the INTEGRAL satellite has revolutionized our knowledge of the hard X-ray sky thanks to its unprecedented imaging capabilities and source detection positional accuracy above 20 keV. Nevertheless, many of the newly-detected sources in the INTEGRAL sky surveys are of unknown nature. The combined use of available information at longer wavelengths (mainly soft X-rays and radio) and of optical spectroscopy on the putative counterparts of these new hard X-ray objects allows us to pinpoint their exact nature. Continuing our long-standing program that has been running since 2004, and using 6 different telescopes of various sizes together with data from an online spectroscopic survey, here we report the classification through optical spectroscopy of 22 more unidentified or poorly studied high-energy sources detected with the IBIS instrument onboard INTEGRAL. We found that 16 of them are active galactic nuclei (AGNs), while the remaining 6 objects are within our Galaxy. Among the identified extragalactic sources, the large majority (14) is made up of type 1 AGNs (i.e. with broad emission lines); of these, 6 lie at redshift larger than 0.5 and one (IGR J12319-0749) has z = 3.12, which makes it the second farthest object detected in the INTEGRAL surveys up to now. The remaining AGNs are of type 2 (that is, with narrow emission lines only), and one of the two cases is confirmed as a pair of interacting Seyfert 2 galaxies. The Galactic objects are identified as two cataclysmic variables, one high-mass X-ray binary, one symbiotic binary and two chromospherically active stars, possibly of RS CVn type. The main physical parameters of these hard X-ray sources were also determined using the multiwavelength information available in the literature. We thus still find that AGNs are the most abundant population among hard X-ray objects identified through optical spectroscopy. Moreover, we note that the higher sensitivity of the more recent INTEGRAL

Report on the 18th International Conference on X-ray and Inner-Shell Processes (X99).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gemmell, D. S.; Physics

2000-01-01

The 18th conference of the series served as a forum for discussing fundamental issues in the field of x-ray and inner-shell processes and their application in various disciplines of science and technology. Special emphasis was given to the opportunities offered by modern synchrotron x-ray sources. The program included plenary talks, progress reports and poster presentations relating to new developments in the field of x-ray and inner-shell processes. The range of topics included: X-ray interactions with atoms, molecules, clusters, surfaces and solids; Decay processes for inner-shell vacancies; X-ray absorption and emission spectroscopy - Photoionization processes; Phenomena associated with highly charged ionsmore » and collisions with energetic particles; Electron-spin and -momentum spectroscopy; X-ray scattering and spectroscopy in the study of magnetic systems; Applications in materials science, biology, geosciences, and other disciplines; Elastic and inelastic x-ray scattering processes in atoms and molecules; Threshold phenomena (post-collision interaction, resonant Raman processes, etc.); Nuclear absorption and scattering of x-rays; 'Fourth-generation' x-ray sources; Processes exploiting the polarization and coherence properties of x-ray beams; Developments in experimental techniques (x-ray optics, temporal techniques, detectors); Microscopy, spectromicroscopy, and various imaging techniques; Non-linear processes and x-ray lasers; Ionization and excitation induced by charged particles and by x-rays; and Exotic atoms (including 'hollow' atoms and atoms that contain 'exotic' particles).« less

The superconducting high-resolution soft X-ray spectrometer at the advanced biological and environmental X-ray facility

NASA Astrophysics Data System (ADS)

Friedrich, S.; Drury, O. B.; George, S. J.; Cramer, S. P.

2007-11-01

We have built a 36-pixel superconducting tunnel junction X-ray spectrometer for chemical analysis of dilute samples in the soft X-ray band. It offers an energy resolution of ˜10-20 eV FWHM below 1 keV, a solid angle coverage of ˜10 -3, and can be operated at total rates of up to ˜10 6 counts/s. Here, we describe the spectrometer performance in speciation measurements by fluorescence-detected X-ray absorption spectroscopy at the Advanced Biological and Environmental X-ray facility at the ALS synchrotron.

X-Ray Weak Broad-Line Quasars: Absorption or Intrinsic X-Ray Weakness

NASA Technical Reports Server (NTRS)

Risaliti, Guido; Mushotzky, Richard F. (Technical Monitor)

2004-01-01

XMM observations of X-ray weak quasars have been performed during 2003. The data for all but the last observation are now available (there has been a delay of several months on the initial schedule, due to high background flares which contaminated the observations: as a consequence, most of them had to be rescheduled). We have reduced and analyzed these data, and obtained interesting preliminary scientific results. Out of the eight sources, 4 are confirmed to be extrimely X-ray weak, in agreement with the results of previous Chandra observations. 3 sources are confirmed to be highly variable both in flux (by factors 20-50) and in spectral properties (dramatic changes in spectral index). For both these groups of objects, an article is in preparation. Preliminary results have been presented at an international workshop on AGN surveys in December 2003, in Cozumel (Mexico). In order to further understand the nature of these X-ray weak quasars, we submitted proposals for spectroscopy at optical and infrared telescopes. We obtained time at the TNG 4 meter telescope for near-IR observations, and at the Hobby-Eberly Telescope for optical high-resolution spectroscopy. These observations will be performed in early 2004, and will complement the XMM data, in order to understand whether the X-ray weakness of these sources is an intrinsic property or is due to absorption by circumnuclear material.

High average power, highly brilliant laser-produced plasma source for soft X-ray spectroscopy.

PubMed

Mantouvalou, Ioanna; Witte, Katharina; Grötzsch, Daniel; Neitzel, Michael; Günther, Sabrina; Baumann, Jonas; Jung, Robert; Stiel, Holger; Kanngiesser, Birgit; Sandner, Wolfgang

2015-03-01

In this work, a novel laser-produced plasma source is presented which delivers pulsed broadband soft X-radiation in the range between 100 and 1200 eV. The source was designed in view of long operating hours, high stability, and cost effectiveness. It relies on a rotating and translating metal target and achieves high stability through an on-line monitoring device using a four quadrant extreme ultraviolet diode in a pinhole camera arrangement. The source can be operated with three different laser pulse durations and various target materials and is equipped with two beamlines for simultaneous experiments. Characterization measurements are presented with special emphasis on the source position and emission stability of the source. As a first application, a near edge X-ray absorption fine structure measurement on a thin polyimide foil shows the potential of the source for soft X-ray spectroscopy.

GSFC Contributions to the NATO X-ray Astronomy Institute, Erice, July 1979. [X-ray spectra of supernova remants, galactic X-ray sources, active galactic nuclei, and clusters of galaxies

NASA Technical Reports Server (NTRS)

Holt, S. S.; Mushotzky, R. F.

1979-01-01

An overview of X-ray astronomical spectroscopy in general is presented and results obtained by HEAO 1 and 2 as well as earlier spacecraft are examined. Particular emphasis is given to the spectra of supernova remnants; galactic binary X-ray sources, cataclysmic variables, bulges, pulsars, and stars; the active nuclei of Seyfert 1 galaxy, BL Lac, and quasars; the diffuse X-ray background; and galactic clusters.

X-ray Weak Broad-line Qquasars: Absorption or Intrinsic X-ray Weakness

NASA Technical Reports Server (NTRS)

Mushotzky, Richard (Technical Monitor); Risaliti, Guida

2005-01-01

XMM observations of X-ray weak quasars have been performed during 2003 and 2004. The data for all the observations have become available in 2004 (there has been a delay of several months on the initial schedule, due to high background flares which contaminated the observations: as a consequence, most of them had to be rescheduled). We have reduced and analyzed all the data, and obtained interesting scientific results. Out of the eight sources, 4 are confirmed to be extremely X-ray weak, in agreement with the results of previous Chandra observations. 3 sources are confined to be highly variable both in flux (by factor 20-50) and in spectral properties (dramatic changes in spectral index). For both these groups of objects we are completing a publication: 1) For the X-ray weak sources, a paper is submitted with a complete analysis of the X-ray spectra both from Chandra and XMM-Newton, and a comparison with optical and near-IR photometry obtained from all-sky surveys. Possible models for the unusual spectral energy distribution of these sources are also presented. 2) For the variable sources, a paper is being finalized where the X-ray spectra obtained with XMM-Newton are compared with previous X-ray observations and with observations at other wavelengths. It is shown that these sources are high luminosity and extreme cases of the highly variable class of narrow-line Seyfert Is. In order to further understand the nature of these X-ray weak quasars, we submitted proposals for spectroscopy at optical and infrared telescopes. We obtained time at the TNG 4 meter telescope for near-IR observations and at the Hobby-Eberly Telescope for optical high-resolution spectroscopy. These observations have been performed in early 2004. They will complement the XMM data and will lead to understanding of whether the X-ray weakness of these sources is an intrinsic property or is due to absorption by circum-nuclear material. The infrared spectra of the variable sources have been already

Crystallography with online optical and X-ray absorption spectroscopies demonstrates an ordered mechanism in copper nitrite reductase.

PubMed

Hough, Michael A; Antonyuk, Svetlana V; Strange, Richard W; Eady, Robert R; Hasnain, S Samar

2008-04-25

Nitrite reductases are key enzymes that perform the first committed step in the denitrification process and reduce nitrite to nitric oxide. In copper nitrite reductases, an electron is delivered from the type 1 copper (T1Cu) centre to the type 2 copper (T2Cu) centre where catalysis occurs. Despite significant structural and mechanistic studies, it remains controversial whether the substrates, nitrite, electron and proton are utilised in an ordered or random manner. We have used crystallography, together with online X-ray absorption spectroscopy and optical spectroscopy, to show that X-rays rapidly and selectively photoreduce the T1Cu centre, but that the T2Cu centre does not photoreduce directly over a typical crystallographic data collection time. Furthermore, internal electron transfer between the T1Cu and T2Cu centres does not occur, and the T2Cu centre remains oxidised. These data unambiguously demonstrate an 'ordered' mechanism in which electron transfer is gated by binding of nitrite to the T2Cu. Furthermore, the use of online multiple spectroscopic techniques shows their value in assessing radiation-induced redox changes at different metal sites and demonstrates the importance of ensuring the correct status of redox centres in a crystal structure determination. Here, optical spectroscopy has shown a very high sensitivity for detecting the change in T1Cu redox state, while X-ray absorption spectroscopy has reported on the redox status of the T2Cu site, as this centre has no detectable optical absorption.

Identifying anthropogenic uranium compounds using soft X-ray near-edge absorption spectroscopy

NASA Astrophysics Data System (ADS)

Ward, Jesse D.; Bowden, Mark; Tom Resch, C.; Eiden, Gregory C.; Pemmaraju, C. D.; Prendergast, David; Duffin, Andrew M.

2017-01-01

Uranium ores mined for industrial use are typically acid-leached to produce yellowcake and then converted into uranium halides for enrichment and purification. These anthropogenic chemical forms of uranium are distinct from their mineral counterparts. The purpose of this study is to use soft X-ray absorption spectroscopy to characterize several common anthropogenic uranium compounds important to the nuclear fuel cycle. Chemical analyses of these compounds are important for process and environmental monitoring. X-ray absorption techniques have several advantages in this regard, including element-specificity, chemical sensitivity, and high spectral resolution. Oxygen K-edge spectra were collected for uranyl nitrate, uranyl fluoride, and uranyl chloride, and fluorine K-edge spectra were collected for uranyl fluoride and uranium tetrafluoride. Interpretation of the data is aided by comparisons to calculated spectra. The effect of hydration state on the sample, a potential complication in interpreting oxygen K-edge spectra, is discussed. These compounds have unique spectral signatures that can be used to identify unknown samples.

Identifying anthropogenic uranium compounds using soft X-ray near-edge absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Jesse D.; Bowden, Mark; Tom Resch, C.

2017-01-01

Uranium ores mined for industrial use are typically acid-leached to produce yellowcake and then converted into uranium halides for enrichment and purification. These anthropogenic chemical forms of uranium are distinct from their mineral counterparts. The purpose of this study is to use soft X-ray absorption spectroscopy to characterize several common anthropogenic uranium compounds important to the nuclear fuel cycle. Non-destructive chemical analyses of these compounds is important for process and environmental monitoring and X-ray absorption techniques have several advantages in this regard, including element-specificity, chemical sensitivity, and high spectral resolution. Oxygen K-edge spectra were collected for uranyl nitrate, uranyl fluoride,more » and uranyl chloride, and fluorine K-edge spectra were collected for uranyl fluoride and uranium tetrafluoride. Interpretation of the data is aided by comparisons to calculated spectra. These compounds have unique spectral signatures that can be used to identify unknown samples.« less

X-ray absorption spectroscopy and EPR studies of oriented spinach thylakoid preparations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, J.C.

In this study, oriented Photosystem II (PS II) particles from spinach chloroplasts are studied with electron paramagnetic resonance (EPR) and x-ray absorption spectroscopy (XAS) to determine more details of the structure of the oxygen evolving complex (OEC). The nature of halide binding to Mn is also studied with Cl K-edge and Mn EXAFS (extended x-ray absorption fine structure) of Mn-Cl model compounds, and with Mn EXAFS of oriented PS II in which Br has replaced Cl. Attention is focused on the following: photosynthesis and the oxygen evolving complex; determination of mosaic spread in oriented photosystem II particles from signal IImore » EPR measurement; oriented EXAFS--studies of PS II in the S{sub 2} state; structural changes in PS II as a result of treatment with ammonia: EPR and XAS studies; studies of halide binding to Mn: Cl K-edge and Mn EXAFS of Mn-Cl model compounds and Mn EXAFS of oriented Br-treated photosystem II.« less

Applications and results of X-ray spectroscopy in implosion experiments on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Epstein, R.; Regan, S. P.; Hammel, B. A.; Suter, L. J.; Scott, H. A.; Barrios, M. A.; Bradley, D. K.; Callahan, D. A.; Cerjan, C.; Collins, G. W.; Dixit, S. N.; Döppner, T.; Edwards, M. J.; Farley, D. R.; Fournier, K. B.; Glenn, S.; Glenzer, S. H.; Golovkin, I. E.; Hamza, A.; Hicks, D. G.; Izumi, N.; Jones, O. S.; Key, M. H.; Kilkenny, J. D.; Kline, J. L.; Kyrala, G. A.; Landen, O. L.; Ma, T.; MacFarlane, J. J.; Mackinnon, A. J.; Mancini, R. C.; McCrory, R. L.; Meyerhofer, D. D.; Meezan, N. B.; Nikroo, A.; Park, H.-S.; Patel, P. K.; Ralph, J. E.; Remington, B. A.; Sangster, T. C.; Smalyuk, V. A.; Springer, P. T.; Town, R. P. J.; Tucker, J. L.

2017-03-01

Current inertial confinement fusion experiments on the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 43, 2841 (2004)] are attempting to demonstrate thermonuclear ignition using x-ray drive by imploding spherical targets containing hydrogen-isotope fuel in the form of a thin cryogenic layer surrounding a central volume of fuel vapor [J. Lindl, Phys. Plasmas 2, 3933 (1995)]. The fuel is contained within a plastic ablator layer with small concentrations of one or more mid-Z elements, e.g., Ge or Cu. The capsule implodes, driven by intense x-ray emission from the inner surface of a hohlraum enclosure irradiated by the NIF laser, and fusion reactions occur in the central hot spot near the time of peak compression. Ignition will occur if the hot spot within the compressed fuel layer attains a high-enough areal density to retain enough of the reaction product energy to reach nuclear reaction temperatures within the inertial hydrodynamic disassembly time of the fuel mass [J. Lindl, Phys. Plasmas 2, 3933 (1995)]. The primary purpose of the ablator dopants is to shield the ablator surface adjacent to the DT ice from heating by the hohlraum x-ray drive [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. Simulations predicted that these dopants would produce characteristic K-shell emission if ablator material mixed into the hot spot [B. A. Hammel et al., High Energy Density Phys. 6, 171 (2010)]. In NIF ignition experiments, emission and absorption features from these dopants appear in x-ray spectra measured with the hot-spot x-ray spectrometer in Supersnout II [S. P. Regan et al., "Hot-Spot X-Ray Spectrometer for the National Ignition Facility," to be submitted to Review of Scientific Instruments]. These include K-shell emission lines from the hot spot (driven primarily by inner-shell collisional ionization and dielectronic recombination) and photoionization edges, fluorescence, and absorption lines caused by the absorption of the

GEMS X-ray Polarimeter Performance Simulations

NASA Technical Reports Server (NTRS)

Baumgartner, Wayne H.; Strohmayer, Tod; Kallman, Tim; Black, J. Kevin; Hill, Joanne; Swank, Jean

2012-01-01

The Gravity and Extreme Magnetism Small explorer (GEMS) is an X-ray polarization telescope selected as a NASA small explorer satellite mission. The X-ray Polarimeter on GEMS uses a Time Projection Chamber gas proportional counter to measure the polarization of astrophysical X-rays in the 2-10 keV band by sensing the direction of the track of the primary photoelectron excited by the incident X-ray. We have simulated the expected sensitivity of the polarimeter to polarized X-rays. We use the simulation package Penelope to model the physics of the interaction of the initial photoelectron with the detector gas and to determine the distribution of charge deposited in the detector volume. We then model the charge diffusion in the detector,and produce simulated track images. Within the track reconstruction algorithm we apply cuts on the track shape and focus on the initial photoelectron direction in order to maximize the overall sensitivity of the instrument, using this technique we have predicted instrument modulation factors nu(sub 100) for 100% polarized X-rays ranging from 10% to over 60% across the 2-10 keV X-ray band. We also discuss the simulation program used to develop and model some of the algorithms used for triggering, and energy measurement of events in the polarimeter.

Preliminary thermal architecture of the X-IFU instrument dewar

NASA Astrophysics Data System (ADS)

Charles, Ivan; Daniel, Christophe; André, Jérome; Duband, Lionel; Duval, Jean-Marc; den Hartog, Roland; Mitsuda, Kazuhisa; Shinozaki, Keisuke; van Weers, Henk; Yamasaki, Noriko Y.

2016-07-01

The ESA Athena mission will implement 2 instruments to study the hot and energetic universe. The X-ray Integral Field Unit (X-IFU) will provide spatially resolved high resolution spectroscopy. This high energy resolution of 2.5 eV at 7 keV could be achieved thanks to TES (Transition Edge Sensor) detectors that need to be cooled to very low temperature. To obtain the required 50 mK temperature level, a careful design of the cryostat and of the cooling chain including different technologies in cascade is needed. The preliminary cryogenic architecture of the X-IFU instrument that fulfils the TES detector thermal requirements is described. In particular, the thermal design of the detector focal plane assembly (FPA), that uses three temperature stages (from 2 K to 50 mK) to limit the thermal loads on the lowest temperature stage, is described. The baseline cooling chain is based on European and Japanese mechanical coolers (Stirling, Pulse tube and Joule Thomson coolers) that precool a sub Kelvin cooler made of a 3He sorption cooler coupled with a small ADR (Adiabatic Demagnetization Refrigerator). Preliminary thermal budgets of the X-IFU cryostat are presented and discussed regarding cooling chain performances.

Disentangling atomic-layer-specific x-ray absorption spectra by Auger electron diffraction spectroscopy

NASA Astrophysics Data System (ADS)

Matsui, Fumihiko; Matsushita, Tomohiro; Kato, Yukako; Hashimoto, Mie; Daimon, Hiroshi

2009-11-01

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.

History of Chandra X-Ray Observatory

NASA Image and Video Library

1995-01-14

This is an artist's concept of the Chandra X-Ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF), fully developed in orbit in a star field with Earth. In 1999, the AXAF was renamed the CXO in honor of the late Indian-American Novel Laureate Subrahmanyan Chandrasekhar. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It is designed to observe x-rays from high energy regions of the Universe, such as hot gas in the renmants of exploded stars. It produces picture-like images of x-ray emissions analogous to those made in visible light, as well as gathers data on the chemical composition of x-ray radiating objects. The CXO helps astronomers world-wide better understand the structure and evolution of the universe by studying powerful sources of x-ray such as exploding stars, matter falling into black holes, and other exotic celestial objects. The Observatory has three major parts: (1) the x-ray telescope, whose mirrors will focus x-rays from celestial objects; (2) the science instruments that record the x-rays so that x-ray images can be produced and analyzed; and (3) the spacecraft, which provides the environment necessary for the telescope and the instruments to work. TRW, Inc. was the prime contractor for the development the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission. (Image courtesy of TRW).

History of Chandra X-Ray Observatory

NASA Image and Video Library

1999-01-01

This is a computer rendering of the fully developed Chandra X-ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF), in orbit in a star field. In 1999, the AXAF was renamed the CXO in honor of the late Indian-American Novel Laureate Subrahmanyan Chandrasekhar. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It is designed to observe x-rays from high energy regions of the Universe, such as hot gas in the renmants of exploded stars. It produces picture-like images of x-ray emissions analogous to those made in visible light, as well as gathers data on the chemical composition of x-ray radiating objects. The CXO helps astronomers world-wide better understand the structure and evolution of the universe by studying powerful sources of x-rays such as exploding stars, matter falling into black holes, and other exotic celestial objects. The Observatory has three major parts: (1) the x-ray telescope, whose mirrors will focus x-rays from celestial objects; (2) the science instruments that record the x-rays so that x-ray images can be produced and analyzed; and (3) the spacecraft, which provides the environment necessary for the telescope and the instruments to work. TRW, Inc. was the prime contractor for the development of the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Smithsonian Astrophysical Observatory controls science and flight operations of the CXO for NASA from Cambridge, Massachusetts. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission. (Image courtesy of TRW).

High-temperature cuprate superconductors studied by x-ray Compton scattering and positron annihilation spectroscopies

NASA Astrophysics Data System (ADS)

Barbiellini, Bernardo

2013-06-01

The bulk Fermi surface in an overdoped (x = 0.3) single crystal of La2-xSrxCuO4 has been observed by using x-ray Compton scattering. This momentum density technique also provides a powerful tool for directly seeing what the dopant Sr atoms are doing to the electronic structure of La2CuO4. Because of wave function effects, positron annihilation spectroscopy does not yield a strong signature of the Fermi surface in extended momentum space, but it can be used to explore the role of oxygen defects in the reservoir layers for promoting high temperature superconductivity.

The Soft X-ray Spectrophotometer SphinX for the CORONAS-Photon Mission

NASA Astrophysics Data System (ADS)

Sylwester, Janusz; Kowalinski, Miroslaw; Szymon, Gburek; Bakala, Jaroslaw; Kuzin, Sergey; Kotov, Yury; Farnik, Frantisek; Reale, Fabio

The purpose, construction details and calibration results of the new design, Polish-led solar X-ray spectrophotometer SphinX will be presented. The instrument constitutes a part of the Russian TESIS X-ray and EUV complex aboard the forthcoming CORONAS-Photon solar mission to be launched later in 2008. SphinX uses Si-PIN detectors for high time resolution (down to 0.01 s) measurements of solar spectra in the energy range between 0.5 keV and 15 keV. The spectral resolution allows separating 256 individual energy channels in this range with particular groups of lines clearly distinguishable. Unprecedented accuracy of the instrument calibration at the XACT (Palermo) and BESSY (Berlin) synchrotron will allow for establishing the solar soft X-ray photometric reference system. The cross-comparison between SphinX and the other instruments presently in orbit like XRT on Hinode, RHESSI and GOES X-ray monitor, will allow for a precise determination of the coronal emission measure and temperature during both very low and very high activity periods. Examples of the detectors' ground calibration results as well as the calculated synthetic spectra will be presented. The operation of the instrument while in orbit will be discussed allowing for suggestions from other groups to be still included in mission planning.

The Generation-X X-ray Observatory Vision Mission and Technology Study

NASA Technical Reports Server (NTRS)

Figueroa-Feliciano, Enectali

2004-01-01

The new frontier in astrophysics is the study of the birth and evolution of the first stars, galaxies and black holes in the early Universe. X-ray astronomy opens a window into these objects by studying the emission from black holes, supernova explosions and the gamma-ray burst afterglows of massive stars. However, such objects are beyond the grasp of current or near-future observatories. X-ray imaging and spectroscopy of such distant objects will require an X-ray telescope with large collecting area and high angular resolution. Our team has conceived the Generation-X Vision Mission based on an X-ray observatory with 100 sq m collecting area at 1 keV (1000 times larger than Chandra) and 0.1 arcsecond angular resolution (several times better than Chandra and 50 times better than the Constellation-X resolution goal). Such an observatory would be capable of detecting the earliest black holes and galaxies in the Universe, and will also study extremes of density, gravity, magnetic fields, and kinetic energy which cannot be created in laboratories. NASA has selected the Generation-X mission for study under its Vision Mission Program. We describe the studies being performed to develop the mission concept and define candidate technologies and performance requirements for Generation-X. The baseline Generation-X mission involves four 8m diameter X-ray telescopes operating at Sun-Earth L2. We trade against an alternate concept of a single 26m diameter telescope with focal plane instruments on a separate spacecraft. A telescope of this size will require either robotic or human-assisted in-flight assembly. The required effective area implies that extremely lightweight grazing incidence X-ray optics must be developed. To achieve the required aerial density of at least 100 times lower than in Chandra, we will study 0.1mm thick mirrors which have active on-orbit figure control. We discuss the suite of required detectors, including a large FOV high angular resolution imager, a

Design of a normal incidence multilayer imaging X-ray microscope

NASA Astrophysics Data System (ADS)

Shealy, David L.; Gabardi, David R.; Hoover, Richard B.; Walker, Arthur B. C., Jr.; Lindblom, Joakim F.

Normal incidence multilayer Cassegrain X-ray telescopes were flown on the Stanford/MSFC Rocket X-ray Spectroheliograph. These instruments produced high spatial resolution images of the sun and conclusively demonstrated that doubly reflecting multilayer X-ray optical systems are feasible. The images indicated that aplanatic imaging soft X-ray/EUV microscopes should be achievable using multilayer optics technology. A doubly reflecting normal incidence multilayer imaging X-ray microscope based on the Schwarzschild configuration has been designed. The design of the microscope and the results of the optical system ray trace analysis are discussed. High resolution aplanatic imaging X-ray microscopes using normal incidence multilayer X-ray mirrors should have many important applications in advanced X-ray astronomical instrumentation, X-ray lithography, biological, biomedical, metallurgical, and laser fusion research.