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1

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

SciTech Connect (OSTI)

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

Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Kameshima, Takashi [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Inubushi, Yuichi; Sato, Takahiro; Hatsui, Takaki; Yabashi, Makina [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)] [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Obara, Yuki; Misawa, Kazuhiko [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan)] [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Bhattacharya, Atanu; Kurahashi, Naoya [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan)] [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Ogi, Yoshihiro [Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan)] [Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan); Suzuki, Toshinori [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan) [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan)

2013-09-23T23:59:59.000Z

2

Transverse pulse shaping and optimization of a tapered hard X-ray free electron laser  

E-Print Network [OSTI]

Multidimensional optimization schemes for TW hard X-Ray free electron lasers are applied to the cases of transversely uniform and parabolic electron beam distributions and compared to examples of transversely Gaussian beams. The optimizations are performed for a $200$m undulator and a resonant wavelength of $\\lambda_r=1.5\\AA $ using the fully 3-dimensional FEL particle code GENESIS. Time dependent simulations showed that the maximum radiation power is larger for flatter transverse distributions due to enhanced optical guiding in the tapered section of the undulator. For a transversely Gaussian beam the maximum output power was found to be $\\text{P}_{max}$=$1.56$ TW compared to $2.26$ TW for the parabolic case and $2.63$ TW for the uniform case. Spectral data also showed a 30-70$\\%$ reduction in energy deposited in the sidebands for the uniform and parabolic beams compared with a Gaussian. An analysis of the maximum power as a function of detuning from resonance shows that redshifting the central wavelength by...

Emma, Claudio; Wu, Juhao

2014-01-01T23:59:59.000Z

3

Fundamental physics at an X-ray free electron laser  

E-Print Network [OSTI]

X-ray free electron lasers (FELs) have been proposed to be constructed both at SLAC in the form of the so-called Linac Coherent Light Source as well as at DESY, where the so-called XFEL laboratory is part of the design of the electron-positron linear collider TESLA. In addition to the immediate applications in condensed matter physics, chemistry, material science, and structural biology, X-ray FELs may be employed also to study some physics issues of fundamental nature. In this context, one may mention the boiling of the vacuum (Schwinger pair creation in an external field), horizon physics (Unruh effect), and axion production. We review these X-ray FEL opportunities of fundamental physics and discuss the necessary technological improvements in order to achieve these goals.

A. Ringwald

2001-12-19T23:59:59.000Z

4

Femtosecond diffractive imaging with a soft-X-ray free-electron laser  

E-Print Network [OSTI]

LETTERS Femtosecond diffractive imaging with a soft-X-ray free-electron laser HENRY N. CHAPMAN1 of this principle using the FLASH soft-X-ray free-electron laser. An intense 25 fs, 4 Ã? 1013 W cm-2 pulse by one10 . X-ray free-electron lasers (FELs) are expected to permit diffractive imaging at high

Loss, Daniel

5

The History of X-ray Free-Electron Lasers  

SciTech Connect (OSTI)

The successful lasing at the SLAC National Accelerator Laboratory of the Linear Coherent Light Source (LCLS), the first X-ray free-electron laser (X-ray FEL), in the wavelength range 1.5 to 15 {angstrom}, pulse duration of 60 to few femtoseconds, number of coherent photons per pulse from 10{sup 13} to 10{sup 11}, is a landmark event in the development of coherent electromagnetic radiation sources. Until now electrons traversing an undulator magnet in a synchrotron radiation storage ring provided the best X-ray sources. The LCLS has set a new standard, with a peak X-ray brightness higher by ten orders of magnitudes and pulse duration shorter by three orders of magnitudes. LCLS opens a new window in the exploration of matter at the atomic and molecular scales of length and time. Taking a motion picture of chemical processes in a few femtoseconds or less, unraveling the structure and dynamics of complex molecular systems, like proteins, are some of the exciting experiments made possible by LCLS and the other X-ray FELs now being built in Europe and Asia. In this paper, we describe the history of the many theoretical, experimental and technological discoveries and innovations, starting from the 1960s and 1970s, leading to the development of LCLS.

Pellegrini, C.; /UCLA /SLAC; ,

2012-06-28T23:59:59.000Z

6

A compact x-ray free electron laser  

SciTech Connect (OSTI)

We present a design concept and simulation of the performance of a compact x-ray, free electron laser driven by ultra-high gradient rf-linacs. The accelerator design is based on recent advances in high gradient technology by a LLNL/SLAC/LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be converted to soft x-rays in the range from 2--10 nm by passage through short period, high field strength wigglers as are being designed at Rocketdyne Linear light sources of this type can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitablee for flash holography of biological specimens in vivo and for studies of fast chemical reactions. 12 refs., 8 figs., 4 tabs.

Barletta, W.A. (California Univ., Los Angeles, CA (USA). Center for Advanced Accelerators Physics Lawrence Livermore National Lab., CA (USA)); Atac, M.; Cline, D.B.; Kolonko, J. (California Univ., Los Angeles, CA (USA). Center for Advanced Accelerators Physics); Bhowmik, A.; Bobbs, B.; Cover, R.A.; Dixon, F.P.; Rakowsky, G. (Rockwell International Corp., Canoga Park, CA (USA). Rocketdyne Div.); Gallardo

1988-01-01T23:59:59.000Z

7

A compact x-ray free electron laser  

SciTech Connect (OSTI)

We present a design concept and simulation of the performance of a compact x-ray, free electron laser driven by ultra-high gradient rf-linacs. The accelerator design is based on recent advances in high gradient technology by a LLNL/SLAC/LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be concerted to soft x-rays in the range from 2--10 nm by passage through short period, high fields strength wigglers as are being designed at Rocketdyne. Linear light sources of this type can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitable for flash holography of biological specimens in vivo and for studies of fast chemical reactions. 12 refs., 8 figs., 4 tabs.

Barletta, W.; Attac, M.; Cline, D.B.; Kolonko, J.; Wang, X.; Bhowmik, A.; Bobbs, B.; Cover, R.A.; Dixon, F.P.; Rakowsky, G.; Gallardo, J.; Pellegrini, C.; Westenskow, G.

1988-09-09T23:59:59.000Z

8

The World's First Free-Electron X-ray Laser | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

First Free-Electron X-ray Laser First Free-Electron X-ray Laser The World's First Free-Electron X-ray Laser August 17, 2010 - 6:19pm Addthis The World's First Free-Electron X-ray Laser John Schueler John Schueler Former New Media Specialist, Office of Public Affairs Yesterday, Secretary Chu participated in the dedication of the world's first free-electron and most powerful X-ray laser, the Linac Coherent Light Source (LCLS). In light of this occasion (pun intended), we posted an in-depth look at the innovative nature of this new instrument and its potential to tackle some of life's biggest mysteries. The Secretary seemed just as geeked about the possibilities of the LCLS, stating that "this is a new instrument that will enable us to see the structure of materials that we could not determine by any other means ... Knowing those

9

Density gradient free electron collisionally excited X-ray laser  

DOE Patents [OSTI]

An operational X-ray laser (30) is provided that amplifies 3p-3s transition X-ray radiation along an approximately linear path. The X-ray laser (30) is driven by a high power optical laser. The driving line focused optical laser beam (32) illuminates a free-standing thin foil (34) that may be associated with a substrate (36) for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the X-ray laser gain medium. The X-ray laser (30) may be driven by more than one optical laser beam (32, 44). The X-ray laser (30) has been successfully demonstrated to function in a series of experimental tests.

Campbell, Edward M. (Pleasanton, CA); Rosen, Mordecai D. (Berkeley, CA)

1989-01-01T23:59:59.000Z

10

Density gradient free electron collisionally excited x-ray laser  

DOE Patents [OSTI]

An operational x-ray laser is provided that amplifies 3p-3s transition x-ray radiation along an approximately linear path. The x-ray laser is driven by a high power optical laser. The driving line focused optical laser beam illuminates a free-standing thin foil that may be associated with a substrate for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the x-ray laser gain medium. The x-ray laser may be driven by more than one optical laser beam. The x-ray laser has been successfully demonstrated to function in a series of experimental tests.

Campbell, E.M.; Rosen, M.D.

1984-11-29T23:59:59.000Z

11

The European X-ray Free-Electron Laser: A Progress Report | Stanford...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

SLAC, Redtail Conference Room (901-108) M. Altarelli, European XFEL GmbH, Hamburg, Germany The present status of the construction of the European X-ray Free-Electron Laser in...

12

Hard x-ray imaging from explorer  

SciTech Connect (OSTI)

Coded aperture X-ray detectors were applied to obtain large increases in sensitivity as well as angular resolution. A hard X-ray coded aperture detector concept is described which enables very high sensitivity studies persistent hard X-ray sources and gamma ray bursts. Coded aperture imaging is employed so that approx. 2 min source locations can be derived within a 3 deg field of view. Gamma bursts were located initially to within approx. 2 deg and X-ray/hard X-ray spectra and timing, as well as precise locations, derived for possible burst afterglow emission. It is suggested that hard X-ray imaging should be conducted from an Explorer mission where long exposure times are possible.

Grindlay, J.E.; Murray, S.S.

1981-11-01T23:59:59.000Z

13

Towards hard x-ray imaging at GHz frame rate  

SciTech Connect (OSTI)

Gigahertz (GHz) imaging using hard x-rays ( Greater-Than-Or-Equivalent-To 10 keV) can be useful to high-temperature plasma experiments, as well as research and applications using coherent photons from synchrotron radiation and x-ray free electron lasers. GHz framing rate can be achieved by using multiple cameras through multiplexing. The advantages and trade-offs of single-photon detection mode, when no more than one x-ray photon is detected per pixel, are given. Two possible paths towards x-ray imaging at GHz frame rates using a single camera are: (a) avalanche photodiode arrays of high-Z materials and (b) microchannel plate photomultipliers in conjunction with materials with large indices of refraction.

Wang Zhehui; Morris, C. L.; Kapustinsky, J. S.; Kwiatkowski, K.; Luo, S.-N. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-10-15T23:59:59.000Z

14

Towards hard X-ray imaging at GHz frame rate  

SciTech Connect (OSTI)

Gigahertz (GHz) imaging using hard X-rays ({approx}> 10 keV) can be useful to high-temperature plasma experiments, as well as research using coherent photons from synchrotron radiation and X-ray free electron lasers. GHz framing rate can be achieved by using multiple cameras through multiplexing. The advantages and trade-offs of single-photon detection mode, when no more than one X-ray photon is detected per pixel, are given. Two possible paths towards X-ray imaging at GHz frame rates using a single camera are (a) Avalanche photodiode arrays of high-Z materials and (b) Microchannel plate photomultipliers in conjunction with materials with large indices of refraction.

Wang, Zhehui [Los Alamos National Laboratory; Morris, Christopher [Los Alamos National Laboratory; Luo, Shengnian [Los Alamos National Laboratory; Kwiatkowski, Kris K. [Los Alamos National Laboratory; Kapustinsky, Jon S. [Los Alamos National Laboratory

2012-05-02T23:59:59.000Z

15

Feasibility considerations of a soft-x-ray distributed feedback laser pumped by an x-ray free electron laser  

E-Print Network [OSTI]

We discuss the feasibility of a soft-x-ray distributed feedback laser (DFL) pumped by an x-ray free electron laser (X-FEL). The DFL under consideration is a Mg/SiC bi-layered Bragg reflector pumped by a single X-FEL bunch at 57.4 eV, stimulating the Mg L2,3 emission at 49 eV corresponding to the 3s-3d â??2p1/2,3/2 transition. Based on a model developed by Yariv and Yeh and an extended coupled-wave theory, we show that it would be possible to obtain a threshold gain compatible with the pumping provided by available X-FEL facilities.

André, Jean-Michel; Jonnard, Philippe

2014-01-01T23:59:59.000Z

16

Toward atomic resolution diffractive imaging of isolated molecules with x-ray free-electron lasers  

E-Print Network [OSTI]

We give a detailed account of the theoretical analysis and the experimental results of an x-ray-diffraction experiment on quantum-state selected and strongly laser-aligned gas-phase ensembles of the prototypical large asymmetric rotor molecule 2,5-diiodobenzonitrile, performed at the Linac Coherent Light Source [Phys. Rev. Lett. 112, 083002 (2014)]. This experiment is the first step toward coherent diffractive imaging of structures and structural dynamics of isolated molecules at atomic resolution, i. e., picometers and femtoseconds, using x-ray free-electron lasers.

Stern, Stephan; Filsinger, Frank; Rouzée, Arnaud; Rudenko, Artem; Johnsson, Per; Martin, Andrew V; Barty, Anton; Bostedt, Christoph; Bozek, John D; Coffee, Ryan N; Epp, Sascha; Erk, Benjamin; Foucar, Lutz; Hartmann, Robert; Kimmel, Nils; Kühnel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Rudek, Benedikt; Starodub, Dmitri G; Thøgersen, Jan; Weidenspointner, Georg; White, Thomas A; Stapelfeldt, Henrik; Rolles, Daniel; Chapman, Henry N; Küpper, Jochen

2014-01-01T23:59:59.000Z

17

Dominant Secondary Nuclear Photoexcitation with the X-ray Free Electron Laser  

E-Print Network [OSTI]

The new regime of resonant nuclear photoexcitation rendered possible by x-ray free electron laser beams interacting with solid state targets is investigated theoretically. Our results unexpectedly show that secondary processes coupling nuclei to the atomic shell in the created cold high-density plasma can dominate direct photoexcitation. As an example we discuss the case of $^{93m}$Mo isomer depletion for which nuclear excitation by electron capture as secondary process is shown to be orders of magnitude more efficient than the direct laser-nucleus interaction. General arguments revisiting the role of the x-ray free electron laser in nuclear experiments involving solid-state targets are further deduced.

Jonas Gunst; Yuri A. Litvinov; Christoph H. Keitel; Adriana Pálffy

2014-02-27T23:59:59.000Z

18

Sharper Focusing of Hard X-rays  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sharper Focusing of Hard X-rays FROM: Physics News Update Number 773 #1, April 12, 2006, by Phil Schewe and Ben Stein Note: This text has been slightly modified from the original. Sharper focusing of hard x-rays has been achieved with a device developed at Argonne National Lab. Because of their high energy, x-rays are hard to focus: they can be reflected from a surface but only at a glancing angle (less than a tenth of a degree); they can be refracted but the index of refraction is very close to 1, so that making efficient lenses becomes a problem; and they can be diffracted, but the relatively thick, variable pitch grating required for focusing is tricky to achieve. The Argonne device is of the diffraction type, and it consists of a stack of alternating layers of metal and silicon, made by depositing progressively thicker layers. When the x-rays fall on such a structure, nearly edge-on, what they see is a grating (called a linear zone plate) consisting of a sort of bar-code pattern.

19

Pulse energy measurement at the hard x-ray laser in Japan  

SciTech Connect (OSTI)

The pulse energies of a free electron laser have accurately been measured in the hard x-ray spectral range. In the photon energy regime from 4.4 keV to 16.8 keV, pulse energies up to 100 {mu}J were obtained at the hard x-ray laser facility SACLA (SPring-8 Angstrom Compact free-electron LAser). Two independent methods, using a cryogenic radiometer and a gas monitor detector, were applied and agreement within 3.3% was achieved. Based on our validated pulse energy measurement, a SACLA online monitor detector could be calibrated for all future experiments.

Kato, M.; Tanaka, T.; Saito, N. [National Institute of Advanced Industrial Science and Technology (AIST), NMIJ, Tsukuba 305-8568 (Japan); RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kurosawa, T. [National Institute of Advanced Industrial Science and Technology (AIST), NMIJ, Tsukuba 305-8568 (Japan); Richter, M. [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, D-10587 Berlin (Germany); Sorokin, A. A. [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, D-22603 Hamburg (Germany); Ioffe Physico-Technical Institute, RAS, Polytekhnicheskaya 26, 194021 St. Petersburg (Russian Federation); Tiedtke, K. [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, D-22603 Hamburg (Germany); Kudo, T.; Yabashi, M. [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Tono, K. [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Ishikawa, T. [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2012-07-09T23:59:59.000Z

20

Spectrometer for X-ray emission experiments at FERMI free-electron-laser  

SciTech Connect (OSTI)

A portable and compact photon spectrometer to be used for photon in-photon out experiments, in particular x-ray emission spectroscopy, is presented. The instrument operates in the 25–800 eV energy range to cover the full emissions of the FEL1 and FEL2 stages of FERMI. The optical design consists of two interchangeable spherical varied-lined-spaced gratings and a CCD detector. Different input sections can be accommodated, with/without an entrance slit and with/without an additional relay mirror, that allow to mount the spectrometer in different end-stations and at variable distances from the target area both at synchrotron and at free-electron-laser beamlines. The characterization on the Gas Phase beamline at ELETTRA Synchrotron (Italy) is presented.

Poletto, L., E-mail: poletto@dei.unipd.it; Frassetto, F.; Miotti, P. [CNR - Institute of Photonics and Nanotechnologies (CNR-IFN), via Trasea 7, I-35131 Padova (Italy); Di Cicco, A.; Iesari, F. [Physics Division, School of Science and Technology, Università di Camerino, I-62032 Camerino (Italy); Finetti, P. [ELETTRA - Sincrotrone Trieste, Basovizza Area Science Park, S. S. 14 - km 163,5, I-34149, Basovizza (TS) (Italy); Grazioli, C. [Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy); CNR-Istituto Officina dei Materiali (CNR-IOM), Laboratorio TASC, I-34149 Trieste (Italy); Kivimäki, A. [CNR-Istituto Officina dei Materiali (CNR-IOM), Laboratorio TASC, I-34149 Trieste (Italy); Stagira, S. [Politecnico di Milano – Department of Physics, I-20133 Milano (Italy); Coreno, M. [ELETTRA - Sincrotrone Trieste, Basovizza Area Science Park, S. S. 14 - km 163,5, I-34149, Basovizza (TS) (Italy); CNR – Istituto di Struttura della Materia (CNR-ISM), UOS Basovizza, I-34149 Trieste (Italy)

2014-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Single-Molecule Imaging with X-Ray Free-Electron Lasers: Dream or Reality?  

SciTech Connect (OSTI)

X-ray free-electron lasers (XFEL) are revolutionary photon sources, whose ultrashort, brilliant pulses are expected to allow single-molecule diffraction experiments providing structural information on the atomic length scale of nonperiodic objects. This ultimate goal, however, is currently hampered by several challenging questions basically concerning sample damage, Coulomb explosion, and the role of nonlinearity. By employing an original ab initio approach, we address these issues showing that XFEL-based single-molecule imaging will be only possible with a few-hundred long attosecond pulses, due to significant radiation damage and the formation of preferred multisoliton clusters which reshape the overall electronic density of the molecular system at the femtosecond scale.

Fratalocchi, A. [PRIMALIGHT, Faculty of Electrical Engineering, Applied Mathematics and Computational Science, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)] [Department of Physics, Sapienza University of Rome, P.le A. Moro 2, 00185, Rome (Italy); Ruocco, G. [Department of Physics, Sapienza University of Rome, P.le A. Moro 2, 00185, Rome (Italy)] [IPCF-CNR, c/o Department of Physics, Sapienza University, P.le Aldo Moro 2, 00185, Rome (Italy)

2011-03-11T23:59:59.000Z

22

Photon Sciences | Beamlines | HXN: Hard X-ray Nanoprobe  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

HXN: Hard X-ray Nanoprobe HXN: Hard X-ray Nanoprobe Poster | Fact Sheet | Preliminary Design Report Scientific Scope The Hard X-ray Nanoprobe beamline and endstation instruments (HXN) will be designed and constructed to explore new frontiers of hard x-ray microscopy applications with the highest achievable spatial resolution. Currently the available spatial resolution for scientific applications, provided by scanning x-ray microscopes in the hard x-ray regime, is limited to ~50nm, which is still insufficient for probing the nanoscale interfacial structures critical in determining properties and functionalities of material and biological systems. The HXN beamline aims to enable x-ray experiments at spatial resolutions ranging from 10 to 30 nm with an ultimate goal of ~1 nm. Beamline Description

23

Three-dimensional manipulation of electron beam phase space for seeding soft x-ray free-electron lasers  

E-Print Network [OSTI]

In this letter, a simple technique is proposed to induce strong density modulation into the electron beam with small energy modulation. By using the combination of a transversely dispersed electron beam and a wave-front tilted seed laser, three-dimensional manipulation of the electron beam phase space can be utilized to significantly enhance the micro-bunching of seeded free-electron laser schemes, which will improve the performance and extend the short-wavelength range of a single-stage seeded free-electron laser. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in a soft x-ray free-electron laser.

Feng, Chao; Deng, Haixiao; Zhao, Zhentang

2014-01-01T23:59:59.000Z

24

R&D for a Soft X-Ray Free Electron Laser Facility  

E-Print Network [OSTI]

x-ray magnetic linear dichroism spectromicroscop,y” Scienceultrafast magnetic phenomena and materials science [44].Magnet Science & Technology, National High Magnetic Field

Staples, John

2009-01-01T23:59:59.000Z

25

The Hard X-ray Sky: Recent Observational Progress  

SciTech Connect (OSTI)

The last fifty years have witnessed the birth, development, and maturation to full potential of hard X-ray astrophysics. The primary force driving the history of the field has been the development of space-based instrumentation optimized for getting the maximum science out of observations of high-energy photons from astrophysical sources. Hard X-ray telescopes are leading research in areas such as galactic diffuse emission, galactic transients, and active galactic nuclei.

Gehrels, Neil [NASA/GSFC/ASD/Code 661, Greenbelt, Md 20071 (United States); Cannizzo, John K. [CRESST/UMBC/NASA/GSFC/ASD/Code 661, Greenbelt, Md 20071 (United States)

2009-05-11T23:59:59.000Z

26

Projected performance of rf-linac-driven free-electron lasers in the VUV and soft x-ray regions  

SciTech Connect (OSTI)

A multidisciplinary team of Los Alamos scientists, supported by the US Department of Energy, has been developing the requisite technologies to extend free-electron laser (FEL) operation from infrared and visible wavelengths into the extreme-ultraviolet below 100 nm using rf-linear accelerator technology. The goal is to establish an XUV Free-Electron Laser User Facility, the next-generation light source that will make available to researchers optical power more than one-million times greater than provided by synchroton light sources. Based primarily on a series of FEL oscillators driven by a single, rf-linac, the Los Alamos facility is designed to generate broadly tunable, picosecond-pulse, coherent radiation spanning the soft x-ray through the ultraviolet to the visible spectral ranges from 1 nm to 400 nm. The FEL facility design is discussed and performance predicted. 3 figs., 5 tabs.

Newnam, B.E.

1987-12-01T23:59:59.000Z

27

Generation of first hard X-ray pulse at Tsinghua Thomson Scattering X-ray Source  

SciTech Connect (OSTI)

Tsinghua Thomson Scattering X-ray Source (TTX) is the first-of-its-kind dedicated hard X-ray source in China based on the Thomson scattering between a terawatt ultrashort laser and relativistic electron beams. In this paper, we report the experimental generation and characterization of the first hard X-ray pulses (51.7 keV) via head-on collision of an 800 nm laser and 46.7 MeV electron beams. The measured yield is 1.0 Multiplication-Sign 10{sup 6} per pulse with an electron bunch charge of 200 pC and laser pulse energy of 300 mJ. The angular intensity distribution and energy spectra of the X-ray pulse are measured with an electron-multiplying charge-coupled device using a CsI scintillator and silicon attenuators. These measurements agree well with theoretical and simulation predictions. An imaging test using the X-ray pulse at the TTX is also presented.

Du Yingchao; Yan Lixin; Hua Jianfei; Du Qiang; Zhang Zhen; Li Renkai; Qian Houjun; Huang Wenhui; Chen Huaibi; Tang Chuanxiang [Accelerator Laboratory, Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle and Radiation Imaging, Tsinghua University, Ministry of Education, Beijing 100084 (China); Key Laboratory of High Energy Radiation Imaging Fundamental Science for National Defense, Tsinghua University, Beijing 100084 (China)

2013-05-15T23:59:59.000Z

28

Beyond hard x-ray photoelectron spectroscopy: Simultaneous combination with x-ray diffraction  

SciTech Connect (OSTI)

Hard x-ray photoelectron spectroscopy (HAXPES) is a powerful and novel emerging technique for the nondestructive determination of electronic properties and chemical composition of bulk, buried interfaces and surfaces. It benefits from the exceptionally large escape depth of high kinetic energy photoelectrons, increasing the information depth up to several tens of nanometers. Complementing HAXPES with an atomic structure sensitive technique (such as x-ray diffraction) opens a new research field with major applications for materials science. At SpLine, the Spanish CRG beamline at the European Synchrotron Radiation Facility, we have developed a novel experimental set-up that combines HAXPES and x-ray diffraction (x-ray reflectivity, surface x-ray diffraction, grazing incidence x-ray diffraction, and reciprocal space maps). Both techniques can be operated simultaneously on the same sample and using the same excitation source. The set-up includes a robust 2S + 3D diffractometer hosting a ultrahigh vacuum chamber equipped with a unique photoelectron spectrometer (few eV < electron kinetic energy < 15 keV), x-ray tube (Mg/Ti), 15 keV electron gun, and auxiliary standard surface facilities (molecular beam epitaxy evaporator, ion gun, low energy electron diffraction, sample heating/cooling system, leak valves, load-lock sample transfer, etc.). This end-station offers the unique possibility of performing simultaneous HAXPES + x-ray diffraction studies. In the present work, we describe the experimental set-up together with two experimental examples that emphasize its outstanding capabilities: (i) nondestructive characterization of the Si/Ge and HfO{sub 2}/SiO{sub 2} interfaces on Ge-based CMOS devices, and (ii) strain study on La{sub 0.7}Ca{sub 0.3}MnO{sub 3} ultrathin films grown on SrTiO{sub 3}(001) substrate.

Rubio-Zuazo, Juan; Castro, German R. [SpLine, Spanish CRG beamline at the European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble (France) and ICMM-CSIC Cantoblanco, E-28049 Madrid (Spain)

2013-05-15T23:59:59.000Z

29

Diffractive imaging at large Fresnel number: Challenge of dynamic mesoscale imaging with hard x rays  

Science Journals Connector (OSTI)

Real materials have structure at both the atomic or crystalline scale as well as at interfaces and defects at the larger scale of grains. There is a need for the study of materials at the “mesoscale,” the scale at which subgranular physical processes and intergranular organization couple to determine microstructure, crucially impacting constitutive response at the engineering macroscale. Diffractive imaging using photons that can penetrate multiple grains of material would be a transformative technique for the study of the performance of materials in dynamic extremes. Thicker samples imply higher energy photons of shorter wavelength, and imaging of multiple grains implies bigger spot sizes. Such imaging requires the use of future planned and proposed hard x-ray free electron lasers (such as the European XFEL) to provide both the spatial coherence transverse to the large spots and the peak brilliance to provide the short illumination times. The result is that the Fresnel number of the system becomes large and is no longer in the Fraunhofer far-field limit. The interrelated issues of diffractive imaging at large Fresnel number are analyzed, including proof that diffractive imaging is possible in this limit and estimates of the signal-to-noise possible. In addition, derivation of the heating rates for brilliant pulses of x rays are presented. The potential and limitations on multiple dynamic images are derived. This paper will present a study of x-ray interactions with materials in this new regime of spatially coherent but relatively large mesoscale spots at very hard energies. It should provide the theory and design background for the experiments and facilities required to control materials in extreme environments, in particular for the next generation of very-hard-x-ray free electron lasers.

John L. Barber; Cris W. Barnes; Richard L. Sandberg; Richard L. Sheffield

2014-05-12T23:59:59.000Z

30

The SIMBOL-X hard X-ray mission  

Science Journals Connector (OSTI)

SIMBOL-X is a hard X-ray mission ... jointly carried out by CNES and ASI. SIMBOL-X makes uses of a long (in ... non focusing techniques used so far. The SIMBOL-X revolutionary instrumental capabilities will allow...

Giovanni Pareschi; Philippe Ferrando

2005-12-01T23:59:59.000Z

31

The SIMBOL-X hard X-ray mission  

Science Journals Connector (OSTI)

SIMBOL-X is a hard X-ray mission ... jointly carried out by CNES and ASI. SIMBOL-X makes uses of a long (in ... non focusing techniques used so far. The SIMBOL-X revolutionary instrumental capabilities will allow...

Giovanni Pareschi; Philippe Ferrando

2006-01-01T23:59:59.000Z

32

Measurements of the hard-x-ray reflectivity of iridium  

SciTech Connect (OSTI)

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

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

2007-01-10T23:59:59.000Z

33

Theory of angular dispersive imaging hard x-ray spectrographs  

E-Print Network [OSTI]

A spectrograph is an optical instrument that disperses photons of different energies into distinct directions and space locations, and images photon spectra on a position-sensitive detector. Spectrographs consist of collimating, angular dispersive, and focusing optical elements. Bragg reflecting crystals arranged in an asymmetric scattering geometry are used as the dispersing elements. A ray-transfer matrix technique is applied to propagate x-rays through the optical elements. Several optical designs of hard x-ray spectrographs are proposed and their performance is analyzed. Spectrographs with an energy resolution of 0.1 meV and a spectral window of imaging up to a few tens of meVs are shown to be feasible for inelastic x-ray scattering (IXS) spectroscopy applications. In another example, a spectrograph with a 1-meV spectral resolution and 85-meV spectral window of imaging is considered for Cu K-edge resonant IXS (RIXS).

Shvyd'ko, Yuri

2015-01-01T23:59:59.000Z

34

Method and apparatus for micromachining using hard X-rays  

DOE Patents [OSTI]

An X-ray source such as a synchrotron which provides a significant spectral content of hard X-rays is used to expose relatively thick photoresist such that the portions of the photoresist at an exit surface receive at least a threshold dose sufficient to render the photoresist susceptible to a developer, while the entrance surface of the photoresist receives an exposure which does not exceed a power limit at which destructive disruption of the photoresist would occur. The X-ray beam is spectrally shaped to substantially eliminate lower energy photons while allowing a substantial flux of higher energy photons to pass through to the photoresist target. Filters and the substrate of the X-ray mask may be used to spectrally shape the X-ray beam. Machining of photoresists such as polymethylmethacrylate to micron tolerances may be obtained to depths of several centimeters, and multiple targets may be exposed simultaneously. The photoresist target may be rotated and/or translated in the beam to form solids of rotation and other complex three-dimensional structures. 21 figs.

Siddons, D.P.; Johnson, E.D.; Guckel, H.; Klein, J.L.

1997-10-21T23:59:59.000Z

35

Method and apparatus for micromachining using hard X-rays  

DOE Patents [OSTI]

An X-ray source such as a synchrotron which provides a significant spectral content of hard X-rays is used to expose relatively thick photoresist such that the portions of the photoresist at an exit surface receive at least a threshold dose sufficient to render the photoresist susceptible to a developer, while the entrance surface of the photoresist receives an exposure which does not exceed a power limit at which destructive disruption of the photoresist would occur. The X-ray beam is spectrally shaped to substantially eliminate lower energy photons while allowing a substantial flux of higher energy photons to pass through to the photoresist target. Filters and the substrate of the X-ray mask may be used to spectrally shape the X-ray beam. Machining of photoresists such as polymethylmethacrylate to micron tolerances may be obtained to depths of several centimeters, and multiple targets may be exposed simultaneously. The photoresist target may be rotated and/or translated in the beam to form solids of rotation and other complex three-dimensional structures.

Siddons, David Peter (Shoreham, NY); Johnson, Erik D. (Ridge, NY); Guckel, Henry (Madison, WI); Klein, Jonathan L. (Madison, WI)

1997-10-21T23:59:59.000Z

36

Constraints on jet X-ray emission in low/hard state X-ray binaries  

E-Print Network [OSTI]

We show that the combination of the similarities between the X-ray properties of low luminosity accreting black holes and accreting neutron stars, combined with the differences in their radio properties argues that the X-rays from these systems are unlikely to be formed in the relativistic jets. Specifically, the spectra of extreme island state neutron stars and low/hard state black holes are known to be indistinguishable, while the power spectra from these systems are known to show only minor differences beyond what would be expected from scaling the characteristic variability frequencies by the mass of the compact object. The spectral and temporal similarities thus imply a common emission mechanism that has only minor deviations from having all key parameters scaling linearly with the mass of the compact object, while we show that this is inconsistent with the observations that the radio powers of neutron stars are typically about 30 times lower than those of black holes at the same X-ray luminosity. We also show that an abrupt luminosity change would be expected when a system makes a spectral state transition from a radiatively inefficient jet dominated accretion flow to a thin disk dominated flow, but that such a change is not seen.

Thomas J. Maccarone

2005-03-31T23:59:59.000Z

37

A Hard X-ray View of Accreting X-ray Binary Pulsars  

E-Print Network [OSTI]

The study of the hard (E>10 keV) energy spectra of X-ray binary pulsars can give a wealth of information on the physical processes that occur close to the neutron star surface. Extreme matter regimes are probed, and precious information on how matter and radiation behave and interact in critical conditions can be obtained. We will give an overview on the most recent results obtained by RXTE and BeppoSAX on this class of objects, in order to pass the baton onto just launched experiments, like INTEGRAL, or soon to be launched, like AGILE and ASTRO-E2.

Mauro Orlandini

2004-02-26T23:59:59.000Z

38

Diffuse scattering of hard x rays from rough surfaces  

Science Journals Connector (OSTI)

The diffuse scattering of hard x rays from rough solid surfaces has been measured and described quantitatively in terms of an improved distorted-wave Born approximation. The rough surface is characterized by the rms roughness ?, the height-height correlation length ?, and the roughness exponent h. The value for ? is in excellent agreement with that deduced from reflectivity. The significance of the parameters ?, ?, and h is tested by comparison with the results obtained from scanning force mircoscopy.

Wolfgang Weber and Bruno Lengeler

1992-09-15T23:59:59.000Z

39

THE SWIFT/BAT HARD X-RAY TRANSIENT MONITOR  

SciTech Connect (OSTI)

The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations.

Krimm, H. A.; Holland, S. T.; Corbet, R. H. D.; Pearlman, A. B.; Baumgartner, W. H.; Cummings, J. R. [Center for Research and Exploration in Space Science and Technology (CRESST) and NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Romano, P. [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy); Kennea, J. A. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Bloom, J. S. [Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720-3411 (United States); Barthelmy, S. D.; Gehrels, N.; Lien, A. Y.; Markwardt, C. B.; Ukwatta, T. N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Palmer, D. M. [Los Alamos National Laboratory, B244, Los Alamos, NM 87545 (United States); Sakamoto, T. [Department of Physics and Mathematics, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258 (Japan); Stamatikos, M. [Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States)

2013-11-01T23:59:59.000Z

40

The Hard X-Ray Nanoprobe Beamline at Argonne National Laboratory  

Science Journals Connector (OSTI)

The hard X-ray nanoprobe at the Advanced Photon Source provides characterizing of composition and structure of nanoscale materials and devices with high spatial-resolution using x-ray...

Maser, Jörg; Holt, Martin V; Winarski, Robert P; Rose, Volker; Stephenson, Gregory Brian; Fuesz, Peter

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

E-Print Network 3.0 - astronomical hard x-ray Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

search results for: astronomical hard x-ray Page: << < 1 2 3 4 5 > >> 1 Reverse Drift Bursts in the 0.8-4.5 GHz Band and their Relation to X-Rays Summary: and causing radio...

42

Production of hard x rays in a plasma focus  

Science Journals Connector (OSTI)

A model of the plasma focus is considered in which large axial electric fields are induced by the imploding current sheet during the final few nanoseconds of the collapse phase. This field provides a mechanism for creation of a beam of electrons of highly suprathermal energies. For such a beam having a power?law energy spectrum the bremsstrahlung radiation above 100 keV to be expected from it both from electron?deuteron collisions in the focused plasma itself and when the beam reaches the walls of the device is calculated. The expected radiation from the walls is found to be several orders of magnitude higher than that from the plasma. Thus since experimental evidence indicates that little or no radiation above 100 keV originates in the walls the conclusion is drawn that the electrons in the beam must be decelerated after leaving the plasma and before reaching the walls. Upon comparison with experimental results qualitative agreement of the expected angular distribution of hard x rays with experiment is found. The total energy in accelerated electrons required to produce the observed total energy in hard x rays by this mechanism is also reasonable when compared with the total energy of the device.

C. E. Newman; Vahé Petrosian

1975-01-01T23:59:59.000Z

43

Long duration hard X-ray transatlantic payload  

SciTech Connect (OSTI)

The HXR80M large-area hard X-ray experiment, to be flown aboard a transatlantic balloon, is described. The detectors are two multiwire spectroscopic proportional counters (MWSPC) with a 2700-sq-cm sensitive area each. The two detectors are filled with an extremely pure xenon-isobutane mixture at high pressure (3-6 atm) in order to obtain good spectral resolution and high efficiency. The onboard data handling is performed by microprocessor-controlled electronics. The scientific aim of the experiment is the survey of the sky belt around the 38th parallel and in particular the observation of faint galactic objects and galactic binary systems in the 15-200 keV range.

La Padula, C.D.; Bazzano, A.; Boccaccini, L.; Mastropietro, M.; Patriarca, R.; Polcaro, V.F.; Ubertini, P.

1981-01-01T23:59:59.000Z

44

Dependence of Hard X-ray Emissions with the Charging Pressure in a Small Plasma Focus  

Science Journals Connector (OSTI)

The dependence with the filling pressure of the hard X-ray emission of a 250 J Plasma-Focus device is presented. The study was performed...

M. Barbaglia; L. Soto; A. Clausse

2012-04-01T23:59:59.000Z

45

Improvement of YOHKOH Hard X-Ray Imaging  

Science Journals Connector (OSTI)

......Figure la shows the X-ray penetration rate through a single, 0.5 mm...index Fig. 1. (a) X-ray penetration rate through a single tung- sten...the K-escape. (b) X-ray penetration rates averaged over the HXT M2 and......

Jun Sato; Takeo Kosugi; Kazuo Makishima

1999-02-01T23:59:59.000Z

46

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

Science Journals Connector (OSTI)

...on electrofocusing, an energy dispersive von Hamos X-ray...spectroscopy data collected by us at the Linac Coherent...deposition of radiation energy by the X-ray pulse was...we review the current status of methods developed in...packages developed by us to process both spectroscopic...

2014-01-01T23:59:59.000Z

47

Probing buried layers by photoelectron spectromicroscopy with hard x-ray excitation  

SciTech Connect (OSTI)

We report about a proof-of-principle experiment which explores the perspectives of performing hard x-ray photoemission spectromicroscopy with high lateral resolution. Our results obtained with an energy-filtered photoemission microscope at the PETRA III storage ring facility using hard x-ray excitation up to 6.5 keV photon energy demonstrate that it is possible to obtain selected-area x-ray photoemission spectra from regions less than 500 nm in diameter.

Wiemann, C.; Patt, M.; Cramm, S. [Peter Gruenberg Institute (PGI-6) and JARA-FIT, Research Centre Juelich, D-52425 Juelich (Germany); Escher, M.; Merkel, M. [FOCUS GmbH, D-65510 Huenstetten (Germany); Gloskovskii, A. [Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitaet Mainz, D-55128 Mainz (Germany); Thiess, S.; Drube, W. [DESY Photon Science, Deutsches Elektronen-Synchrotron, D-22603 Hamburg (Germany); Schneider, C. M. [Peter Gruenberg Institute (PGI-6) and JARA-FIT, Research Centre Juelich, D-52425 Juelich (Germany); Fakultaet f. Physik and Center for Nanointegration Duisburg-Essen (CENIDE), Universitaet Duisburg-Essen, D-47048 Duisburg (Germany)

2012-05-28T23:59:59.000Z

48

Regularized reconstruction of the differential emission measure from solar flare hard X-ray spectra  

E-Print Network [OSTI]

Regularized reconstruction of the differential emission measure from solar flare hard X-ray spectra for solar flare hard X-rays, it is currently unclear whether the electron distribution responsible between (T) and J( ). However, in the last years, two issues have made this inversion problem more

Piana, Michele

49

Exploring electronic structure through high-resolution hard x-ray  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Exploring electronic structure through high-resolution hard x-ray Exploring electronic structure through high-resolution hard x-ray spectroscopies Tuesday, July 23, 2013 - 11:00am SLAC, Conference Room 137-322 Presented by Dimosthenis Sokaras, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory Modern high brilliance beamlines coupled with recent advances in hard-x-ray optics are establishing high-resolution hard x-ray spectroscopies as a powerful analytical tool for routine electronic structure investigations. Their advantageous characteristics like the chemical sensitivity or the hard x-rays penetration depth, that permits the implementation of difficult sample environments, expand the applicability of the relevant studies to multidisciplinary scientific fields. Simultaneously, the experimental

50

Hard X-ray tails and cyclotron features in X-ray pulsars  

E-Print Network [OSTI]

We review the physical processes occurring in the magnetosphere of accreting X-ray pulsars, with emphasis on those processes that give rise to observable effects in their high (E>10 keV) energy spectra. In the second part we compare the empirical spectral laws used to fit the observed spectra with theoretical models, at the light of the BeppoSAX results on the broad-band characterization of the X-ray pulsar continuum, and the discovery of new (multiple) cyclotron resonance features.

Mauro Orlandini; Daniele Dal Fiume

2001-07-27T23:59:59.000Z

51

Hard X-ray Emission and Efficient Particle Acceleration by Supernova Remnants  

SciTech Connect (OSTI)

I discuss the non-thermal X-ray emission from young supernova remnants. Over the last decade it has become clear from both X-ray and {gamma}-ray observations that young supernovae accelerate particles up to 100 TeV. In soft X-rays the accelerated >10 TeV electrons produce synchrotron radiation, coming from narrow filaments located at the shock fronts. The width of these filaments shows that the magnetic fields are relatively high, thus providing evidence for magnetic field amplification.The synchrotron radiation of several remnants is known to extend into the hard X-ray regime. In particular Cas A, has a spectrum that appears as a power law up to almost 100 TeV. This is very surprising, as a steepening is expected going from the soft to the hard X-ray band. The spectrum is likely a result of many superimposed individual spectra, each steepening at different energies. This implies considerable spatial variation in hard X-rays, an obvious target for Simbol-X. The variations will be important to infer local shock acceleration properties, but also magnetic field fluctuations may cause spatial and temporal variations.Finally, I draw the attention to super bubbles and supernovae as sources of cosmic rays. As such they may be sources of hard X-ray emission. In particular, supernovae exploding inside the dense red supergiants winds of their progenitors ares promising candidates for hard X-ray emission.

Vink, Jacco [Astronomical Institute Utrecht, Utrecht University, P.O. Box 80000, 3508TA Utrecht (Netherlands)

2009-05-11T23:59:59.000Z

52

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

Science Journals Connector (OSTI)

...Coherent Light Source, taking...Coherent Light Source (LCLS...radiation energy by the X-ray...developed by us to process...large sample consumption is not sustainable...Coherent Light Source (LCLS...operated for the US Department of Energy Office of...

2014-01-01T23:59:59.000Z

53

Hard X-ray latitude effect measured during a transatlantic balloon flight  

SciTech Connect (OSTI)

The hard X-ray latitude effect is reported in the range of McIlwain shell parameter L from 1.4 to 2.6 (earth radius units). The data were obtained with two X-ray scintillator detectors flown on board a transatlantic balloon launched from Trapani, Sicily. The data analysis method for measuring the flux from weak X-ray sources is also described.

Frontera, F. (CNR, Istituto Plasma Spazio, Frascati, Italy); Fuligni, F. (CNR, Istituto di Tecnologie e Studio delle Radiazioni Extraterrestri, Bologna, Italy)

1981-01-01T23:59:59.000Z

54

PUBLISHED VERSION Study of runaway electrons with Hard X-ray spectrometry of tokamak plasmas  

E-Print Network [OSTI]

electrons using dosimetry of hard x-ray radiations in Damavand tokamak Rev. Sci. Instrum. 85, 053509 (2014 Kingdom c Instituto de Plasmas e Fusão Nuclear, Associação EURATOM-IST, Instituto Superior Tecnico

55

DEDUCING ELECTRON PROPERTIES FROM HARD X-RAY OBSERVATIONS  

E-Print Network [OSTI]

of the accelerated electron distribution. Keywords: Sun: flares; Sun: X-rays; Sun: acceleration; Sun: energetic distribution 31 4.5 Low-energy cutoffs in the electron distribution 32 4.6 Temperature distribution of thermal-ray emission process(es) in question with the electron distribution function, which is in turn a function

Piana, Michele

56

Tailoring a plasma focus as hard x-ray source for imaging  

Science Journals Connector (OSTI)

An investigation on temporal and spatial properties of hard x-rays (15–88 keV) emitted in a 5.3 kJ plasma focus using Si pin diodes and a pinhole camera is reported. The maximum yield of hard x-rays of 15–88 keV range is estimated about 4.7 J and corresponding efficiency for x-ray generation is 0.09%. The x-rays with energy > 15 ? keV have 15–20 ns pulse duration and ? 1 ? mm source size. This radiation is used for contact x-ray imaging of biological and compound objects and spatial resolution of ? 50 ? ? m is demonstrated.

S. Hussain; M. Shafiq; M. Zakaullah

2010-01-01T23:59:59.000Z

57

HARD X-RAY OBSERVATIONS OF A JET AND ACCELERATED ELECTRONS IN THE CORONA  

SciTech Connect (OSTI)

We report the first hard X-ray observation of a solar jet on the limb with flare footpoints occulted, so that faint emission from accelerated electrons in the corona can be studied in detail. In this event on 2003 August 21, RHESSI observed a double coronal hard X-ray source in the pre-impulsive phase at both thermal and nonthermal energies. In the impulsive phase, the first of two hard X-ray bursts consists of a single thermal/nonthermal source coinciding with the lower of the two earlier sources, and the second burst shows an additional nonthermal, elongated source, spatially and temporally coincident with the coronal jet. Analysis of the jet hard X-ray source shows that collisional losses by accelerated electrons can deposit enough energy to generate the jet. The hard X-ray time profile above 20 keV matches that of the accompanying Type III and broadband gyrosynchrotron radio emission, indicating both accelerated electrons escaping outward along the jet path and electrons trapped in the flare loop. The double coronal hard X-ray source, the open field lines indicated by Type III bursts, and the presence of a small post-flare loop are consistent with significant electron acceleration in an interchange reconnection geometry.

Glesener, Lindsay; Lin, R. P.; Krucker, Saem, E-mail: glesener@ssl.berkeley.edu [Space Science Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States)

2012-07-20T23:59:59.000Z

58

Study of the Feasibility of an X-Ray Free Electron Laser with a 15 GeV CLIC Beam  

E-Print Network [OSTI]

This note presents a study of the feasibility of a Free Electron Laser (FEL) using an electron beam from the Compact Linear Collider (CLIC). We first show that, with the nominal CLIC layout, the energy spread at 15 GeV would be too large to allow FEL saturation in an undulator of reasonable length. An alternative scheme was studied, with a dedicated source, with a by-pass of the damping rings and with magnetic compression between the various acceleration stages. With this scheme, the energy spread of the CLIC beam can be reduced from 1.5% to 0.1%, but the emittance is much larger and, although the power gain is better than in the nominal case, FEL saturation is still not reached. We show that the energy spread or the transverse emittance would have to be reduced by another order of magnitude in order to obtain FEL saturation.

Brandin, M; Ekelöf, T J C; Ferrari, A

2002-01-01T23:59:59.000Z

59

Using X-ray free-electron lasers for probing of complex interaction dynamics of ultra-intense lasers with solid matter  

SciTech Connect (OSTI)

We demonstrate the potential of X-ray free-electron lasers (XFEL) to advance the understanding of complex plasma dynamics by allowing for the first time nanometer and femtosecond resolution at the same time in plasma diagnostics. Plasma phenomena on such short timescales are of high relevance for many fields of physics, in particular in the ultra-intense ultra-short laser interaction with matter. Highly relevant yet only partially understood phenomena become directly accessible in experiment. These include relativistic laser absorption at solid targets, creation of energetic electrons and electron transport in warm dense matter, including the seeding and development of surface and beam instabilities, ambipolar expansion, shock formation, and dynamics at the surfaces or at buried layers. In this paper, we focus on XFEL plasma probing for high power laser matter interactions based on quantitative calculations using synthesized data and evaluate the feasibility of various imaging and scattering techniques with special focus on the small angle X-ray scattering technique.

Kluge, T., E-mail: t.kluge@hzdr.de; Huang, L. G.; Metzkes, J.; Bussmann, M. [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany)] [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany); Gutt, C. [Universität Siegen, D-57068 Siegen (Germany)] [Universität Siegen, D-57068 Siegen (Germany); Schramm, U.; Cowan, T. E. [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany) [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany); Technische Universität Dresden, D-01062 Dresden (Germany)

2014-03-15T23:59:59.000Z

60

Runaway electron energy measurement using hard x-ray spectroscopy in 'Damavand' tokamak  

SciTech Connect (OSTI)

Set of experiments has been developed to study existing runaway electrons in ''Damavand'' tokamak plasma upon characteristics of hard x-ray emissions produced by collision of the runaway electrons with the plasma particles and limiters. As a first step, spatial distribution of hard x-ray emissions on the equatorial plane of the torus was considered. Obtained spectra of hard x-ray emissions for different alignments of shielded detector indicate isotropic emissivity in the equatorial plane. This is in agreement with wide angle cone of bremsstrahlung radiations, deduced from the mean value of energy of the runaway electrons. The mean energy was calculated from the slope of the energy spectrum of hard x-ray photons. In the second stage in order to investigate time evolution of energy of the runaway electrons, similar technique were applied to obtain hard x-ray energy in every 3 ms intervals, from the beginning to the end of plasma. The mean energy of the runaway electrons increases during the ramp up phase and reaches its maximum between 3 and 9 ms after plasma formation. Also considering the time dependence of the counted photons in each energy range shows that energetic photons are emitted during the ramp up phase of the plasma current in Damavand tokamak.

Rasouli, C.; Farahbod, A. H.; Rasouli, H.; Lamehi, M. [School of Plasma Physics and Nuclear Fusion, Institute of Nuclear Science and Technology, AEOI, P.O. Box 14155-1339, Tehran (Iran, Islamic Republic of); Iraji, D. [Centre de Recherches en Physique des Plasmas, Association EURATOM-Confederation Suisse, Ecole Polytechnique Federale de Lausanne, CH-1015 (Switzerland); Akhtari, K. [Department of Physics, Sharif University of Technology, P.O. Box 11365-9161, Tehran (Iran, Islamic Republic of); Modarresi, H. [Department of Mechanical Engineering, Sharif University of Technology, P.O. Box 11365-9567, Tehran (Iran, Islamic Republic of)

2009-01-15T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Argonne CNM HighlightL Hard X-ray characterization of fly ash geopolymers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Hard X-ray characterization of fly ash geopolymers Hard X-ray characterization of fly ash geopolymers Calcium Map Calcium map of an activated fly ash geopolymer displays regions of high calcium concentration (circled). Their distribution suggests localization as a discrete calcium-rich phase within the lower-calcium aluminosilicate geopolymer gel. Use of the Hard X-Ray Nanoprobe (HXN) has provided the first access to the nature of heterogeneity in real fly ash-derived geopolymers at the nanoscale. Direct evidence of the formation of discrete high-calcium nanometer-sized particles within a hydroxide-activated geopolymer synthesized from a low-calcium fly ash has been obtained using HXN fluorescence characterization. Additionally, the team of CNM users from the University of Melbourne, the Universidad del Valle of Colombia, and the

62

THE HARD X-RAY SPECTRUM OF NGC 1365: SCATTERED LIGHT, NOT BLACK HOLE SPIN  

SciTech Connect (OSTI)

Active galactic nuclei (AGNs) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (1) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (2) neglect of the effect of Compton scattering on transmitted spectra, and (3) inadequate modeling of the spectrum of scattered X-rays. The scattered spectrum is geometry-dependent and, for high global covering factors, may dominate above 10 keV. We further show that, in models of circumnuclear gas, the suppression of the observed hard X-ray flux by reprocessing may be no larger than required by the ''light bending'' model invoked for inner disk reflection, and the expected emission line strengths lie within the observed range. We conclude that the time-invariant ''red wing'' in AGN X-ray spectra is probably caused by continuum transmitted through and scattered from circumnuclear gas, not by highly redshifted line emission, and that measurement of black hole spin is not possible.

Miller, L. [Department of Physics, Oxford University, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Turner, T. J. [Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250 (United States)

2013-08-10T23:59:59.000Z

63

Experimental Study of Hard X-ray Emission with Different Anode Tips in APF Plasma Focus Device  

Science Journals Connector (OSTI)

To investigate the effect of different anode tips on the hard X-ray (HXR) emission from APF plasma focus device (16 kV, 36 ?f, and...

M. Habibi; R. Amrollahi; G. R. Etaati

2010-02-01T23:59:59.000Z

64

Hard x-ray or gamma ray laser by a dense electron beam  

E-Print Network [OSTI]

A coherent x-ray or gamma ray can be created from a dense electron beam propagating through an intense laser undulator. It is analyzed by using the Landau damping theory which suits better than the conventional linear analysis for the free electron laser, as the electron beam energy spread is high. The analysis suggests that the currently available physical parameters would enable the generation of the coherent gamma ray of up to 100 keV. The electron quantum diffraction suppresses the FEL action, by which the maximum radiation energy to be generated is limited.

S. Son; S. J. Moon

2012-02-12T23:59:59.000Z

65

MODELING THE THERMAL DIFFUSE SOFT AND HARD X-RAY EMISSION IN M17  

SciTech Connect (OSTI)

We present numerical models of very young wind driven superbubbles. The parameters chosen for the simulations correspond to the particular case of the M17 nebula, but are appropriate for any young superbubble in which the wind sources have not completely dispersed their parental cloud. From the simulations, we computed the diffuse emission in the soft ([0.5-1.5] keV) and hard ([1.5-5] keV) X-ray bands. The total luminosity in our simulations agrees with the observations of Hyodo et al., about two orders of magnitude below the prediction of the standard model of Weaver et al.. The difference with respect to the standard (adiabatic) model is the inclusion of radiative cooling, which is still important in such young bubbles. We show that for this type of object the diffuse hard X-ray luminosity is significant compared to that of soft X-rays, contributing as much as 10% of the total luminosity, in contrast with more evolved bubbles where the hard X-ray emission is indeed negligible, being at least four orders of magnitude lower than the soft X-ray emission.

Velazquez, P. F.; Rodriguez-Gonzalez, A.; Esquivel, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico)] [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico); Rosado, M. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Ap. 70-248, 04510 D.F. (Mexico)] [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Ap. 70-248, 04510 D.F. (Mexico); Reyes-Iturbide, J., E-mail: pablo@nucleares.unam.mx, E-mail: ary@nucleares.unam.mx, E-mail: esquivel@nucleares.unam.mx, E-mail: margarit@astro.unam.mx [LATO-DCET/Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-000 Ilheus, BA (Brazil)

2013-04-10T23:59:59.000Z

66

Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak  

SciTech Connect (OSTI)

In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points – three TLDs per point – to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

Rasouli, C.; Pourshahab, B.; Rasouli, H. [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)] [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of); Hosseini Pooya, S. M.; Orouji, T. [Radiation Application Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)] [Radiation Application Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)

2014-05-15T23:59:59.000Z

67

SSRL School 2007 on Hard X-ray Scattering Techniques in MES  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

May 15-17, 2007 SSRL School on Hard X-ray Scattering Techniques in Materials and Environmental Sciences Group photo taken at the SSRL School on Hard X-ray Scattering Techniques in Materials and Environmental Sciences. A large, printable version of this group image is available via clicking on the image. Overview: Modern synchrotron-based X-ray scattering (SR-XRS) techniques offer the ability to probe nano- and atomic-scale structures and order/disorder relationships that critically govern the properties of advanced technological and environmental materials. The high collimation, intensity, and tunability of SR allow the investigation of a wide range of materials, including thin films and interfaces, nanoparticles, amorphous materials, solutions, hydrated and disordered bacteriogenic minerals,

68

A New Multilayer-Based Grating for Hard X-ray Grating Interferometry |  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The Most Detailed Picture Yet of a Key AIDS Protein The Most Detailed Picture Yet of a Key AIDS Protein Superconductivity with Stripes How HIV Infects Cells Simulating Deep Earthquakes in the Laboratory A "Sponge" Path to Better Catalysts and Energy Materials Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed A New Multilayer-Based Grating for Hard X-ray Grating Interferometry November 20, 2013 Bookmark and Share An image of the phase shift in the mouse kidney from a Bonse-Hart interferometer built utilizing the new micro-multilayer grating provides a projection view of the blood vessels. A new kind of x-ray multilayer grating that could open a pathway for high-sensitivity, hard x-ray phase contrast full-field imaging of large

69

A robot-based detector manipulator system for a hard x-ray nanoprobe instrument.  

SciTech Connect (OSTI)

This paper presents the design of a robot-based detector manipulator for microdiffraction applications with a hard X-ray nanoprobe instrument system being constructed at the Advanced Photon Source (APS) for the Center for Nanoscale Materials (CNM) being constructed at Argonne National Laboratory (ANL). Applications for detectors weighing from 1.5 to 100 kg were discussed in three configurations.

Shu, D., Maser, J., Holt, M. , Winarski, R., Preissner, C.,Lai, B., Vogt, S., Stephenson, G.B.

2007-11-11T23:59:59.000Z

70

Hard X-ray Sources from Miniature Plasma Focus Devices Vernica Raspa1  

E-Print Network [OSTI]

Hard X-ray Sources from Miniature Plasma Focus Devices Verónica Raspa1 , Patricio Silva, José been obtained. Introduction The plasma focus (PF) device is a known source of dense transient high temperature plasmas, and it has been studied since late 50`s [1] . A plasma focus is a particular pinch

Paris-Sud XI, Université de

71

ELECTRON FLUX SPECTRAL IMAGING OF SOLAR FLARES THROUGH REGULARIZED ANALYSIS OF HARD X-RAY SOURCE VISIBILITIES  

E-Print Network [OSTI]

ELECTRON FLUX SPECTRAL IMAGING OF SOLAR FLARES THROUGH REGULARIZED ANALYSIS OF HARD X-RAY SOURCE a new method for imaging spectroscopy analysis of hard X-ray emission during solar flares. The method.e., the two-dimensional spatial Fourier transforms of the spectral image) to obtain smoothed (regularized

Piana, Michele

72

Optical identification of hard X-ray source IGRJ18257-0707  

E-Print Network [OSTI]

We present the results of the optical identification of hard X-ray source IGRJ18257-0707 trough the spectroscopic observations of its optical counterpart with RTT150 telescope. Accurate position of the X-ray source, determined using Chandra observations, allowed us to associate this source with the faint optical object (m_R=~20.4), which shows broad H_\\alpha emission line in its optical spectrum. Therefore we conclude that the source IGRJ18257-0707 is a type 1 Seyfert galaxy at redshift z=0.037.

R. A. Burenin; I. F. Bikmaev; M. G. Revnivtsev; J. A. Tomsick; S. Yu. Sazonov; M. N. Pavlinskiy; R. A. Sunyaev

2008-10-14T23:59:59.000Z

73

Nonthermal hard X-ray excess in the cluster Abell 2256 from two epoch observations  

E-Print Network [OSTI]

After confirmation of the presence of a nonthermal hard X-ray excess with respect to the thermal emission in the Coma cluster from two independent observations, obtained using the Phoswich Detection System onboard BeppoSAX, we present in this Letter also for Abell 2256 the results of two observations performed with a time interval of about 2.5 yr. In both spectra a nonthermal excess is present at a confidence level of ~3.3sigma and ~3.7sigma, respectively. The combined spectrum obtained by adding up the two spectra allows to measure an excess at the level of ~4.8sigma in the 20-80 keV energy range. The nonthermal X-ray flux is in agreement with the published value of the first observation (Fusco-Femiano et al. 2000) and with that measured by a Rossi X-Ray Timing Explorer observation (Rephaeli & Gruber 2003).

Roberto Fusco-Femiano; Raffaella Landi; Mauro Orlandini

2005-04-06T23:59:59.000Z

74

EXIST A High Sensitivity Hard X-ray Imaging Sky Survey Mission for ISS  

E-Print Network [OSTI]

A deep all-sky imaging hard x-ray survey and wide-field monitor is needed to extend soft (ROSAT) and medium (ABRIXAS2) x-ray surveys into the 10-100 keV band (and beyond) at comparable sensitivity (~0.05 mCrab). This would enable discovery and study of >3000 obscured AGN, which probably dominate the hard x-ray background; detailed study of spectra and variability of accreting black holes and a census of BHs in the Galaxy; Gamma-ray bursts and associated massive star formation (PopIII) at very high redshift and Soft Gamma-ray Repeaters throughout the Local Group; and a full galactic survey for obscured supernova remnants. The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed array of 8 x 1m^2 coded aperture telescopes fixed on the International Space Station (ISS) with 160deg x 40deg field of view which images the full sky each 90 min orbit. EXIST has been included in the most recent NASA Strategic Plan as a candidate mission for the next decade. An overview of the science goals and mission concep...

Grindlay, J; Chakraborty, D; Elvis, M; Fabian, A C; Fiore, F; Gehrels, N; Hailey, C J; Harrison, F; Hartmann, D; Prince, T A; Ramsey, B; Rothschild, R; Skinner, G K; Woosley, S

1999-01-01T23:59:59.000Z

75

Sensitivity of Stacked Imaging Detectors to Hard X-Ray Polarization  

Science Journals Connector (OSTI)

The development of multi-layer optics which allow to focus photons up to 100 keV and more promises an enormous jump in sensitivity in the hard X-ray energy band. This technology is already planned to be exploited by future missions dedicated to spectroscopy and imaging at energies >10 keV, e.g., Astro-H and NuSTAR. Nevertheless, our understanding of the hard X-ray sky would greatly benefit from carrying out contemporaneous polarimetric measurements, because the study of hard spectral tails and of polarized emission are often two complementary diagnostics of the same non-thermal and acceleration processes. At energies above a few tens of keV, the preferred technique to detect polarization involves the determination of photon directions after a Compton scattering. Many authors have asserted that stacked detectors with imaging capabilities can be exploited for this purpose. If it is possible to discriminate those events which initially interact in the first detector by Compton scattering and are subsequently absorbed by the second layer, then the direction of scattering is singled out from the hit pixels in the two detectors. In this paper, we give the first detailed discussion of the sensitivity of such a generic design to the X-ray polarization. The efficiency and the modulation factor are calculated analytically from the geometry of the instruments and then compared with the performance as derived by means of Geant4 Monte Carlo simulations.

Fabio Muleri; Riccardo Campana

2012-01-01T23:59:59.000Z

76

THE 70 MONTH SWIFT-BAT ALL-SKY HARD X-RAY SURVEY  

SciTech Connect (OSTI)

We present the catalog of sources detected in 70 months of observations with the Burst Alert Telescope (BAT) hard X-ray detector on the Swift gamma-ray burst observatory. The Swift-BAT 70 month survey has detected 1171 hard X-ray sources (more than twice as many sources as the previous 22 month survey) in the 14-195 keV band down to a significance level of 4.8{sigma}, associated with 1210 counterparts. The 70 month Swift-BAT survey is the most sensitive and uniform hard X-ray all-sky survey and reaches a flux level of 1.03 Multiplication-Sign 10{sup -11} erg s{sup -1} cm{sup -2} over 50% of the sky and 1.34 Multiplication-Sign 10{sup -11} erg s{sup -1} cm{sup -2} over 90% of the sky. The majority of new sources in the 70 month survey continue to be active galactic nuclei, with over 700 in the catalog. As part of this new edition of the Swift-BAT catalog, we also make available eight-channel spectra and monthly sampled light curves for each object detected in the survey in the online journal and at the Swift-BAT 70 month Web site.

Baumgartner, W. H.; Tueller, J.; Markwardt, C. B.; Skinner, G. K.; Barthelmy, S.; Gehrels, N. [NASA/Goddard Space Flight Center, Astrophysics Science Division, Greenbelt, MD 20771 (United States); Mushotzky, R. F. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Evans, P. A., E-mail: whbaumga@alum.mit.edu [X-Ray and Observational Astronomy Group/Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom)

2013-08-15T23:59:59.000Z

77

Plasma focus based flash hard X-ray source in the 100 keV region with reproducible spectrum  

Science Journals Connector (OSTI)

A pulsed hard X-ray source with shot to shot reproducible spectrum, based on a 4.7 kJ small-chamber Mather-type plasma focus device, is presented. The hard X-ray output spectrum was measured in a single shot basis by differential absorption on metallic plates. The measured spectra have a single dominant peak around 75 keV and a spectral bandwidth covering the 40–150 keV range. A hard X-ray dose of ( 53 ± 3 ) ?Gy per shot was measured on axis at 53 cm from the source, and found to be uniform within a half aperture angle of 6°.

V. Raspa; P. Knoblauch; F. Di Lorenzo; C. Moreno

2010-01-01T23:59:59.000Z

78

A Laboratory-based Hard X-ray Monochromator for High-Resolution X-ray Emission Spectroscopy and X-ray Absorption Near Edge Structure Measurements  

E-Print Network [OSTI]

We report the development of a laboratory-based Rowland-circle monochromator that incorporates a low poer x-ray (bremsstrahlung) tube source, a spherically-bent crystal analyzer (SBCA), and an energy-resolving solid-state detector. This relatively inexpensive, introductory level instrument achieves 1-eV energy resolution for photon energies of 5 keV to 10 keV while also dmeonstrating a net efficiency previously seen only in laboratory monochromators having much coarser energy resolution. Despite the use of only a compact, air-cooled 10 W x-ray tube, we find count rates for nonresonant x-ray emission spectroscopy (XES) comparable to those achived at monochromatized spectroscopy beamlines at synchrotron light sources. For x-ray absorption near edge structure (XANES), the monochromatized flux is small (due to the use of a low-powered x-ray generator) but still useful for routine transmission-mode studies of concentrated samples. These results indicate that upgrading to a standard commercial high-powered line-foc...

Seidler, G T; Remesnik, A J; Pacold, J I; Ball, N A; Barry, N; Styczinski, M; Hoidn, O R

2014-01-01T23:59:59.000Z

79

Anisotropic Investigation of Hard X-ray Emission with Flat Anode Tips in APF Plasma Focus Device  

Science Journals Connector (OSTI)

In this paper behavior of hard X-ray (HXR) anisotropy and its intensity along the anode bar from APF plasma focus facility (16 kV, 36 ?f, and...

M. Habibi; R. Amrollahi

2010-04-01T23:59:59.000Z

80

A Suzaku Search for Nonthermal Emission at Hard X-Ray Energies in the Coma Cluster  

Science Journals Connector (OSTI)

The brightest cluster radio halo known resides in the Coma cluster of galaxies. The relativistic electrons producing this diffuse synchrotron emission should also produce inverse Compton emission that becomes competitive with thermal emission from the intracluster medium (ICM) at hard X-ray energies. Thus far, claimed detections of this emission in Coma are controversial. We present a Suzaku HXD-PIN observation of the Coma cluster in order to nail down its nonthermal hard X-ray content. The contribution of thermal emission to the HXD-PIN spectrum is constrained by simultaneously fitting thermal and nonthermal models to it and a spatially equivalent spectrum derived from an XMM-Newton mosaic of the Coma field. We fail to find statistically significant evidence for nonthermal emission in the spectra which are better described by only a single- or multitemperature model for the ICM. Including systematic uncertainties, we derive a 90% upper limit on the flux of nonthermal emission of 6.0 ? 10–12 erg s–1 cm–2 (20-80 keV, for ? = 2.0), which implies a lower limit on the cluster-averaged magnetic field of B>0.15 ?G. Our flux upper limit is 2.5 times lower than the detected nonthermal flux from RXTE and BeppoSAX. However, if the nonthermal hard X-ray emission in Coma is more spatially extended than the observed radio halo, the Suzaku HXD-PIN may miss some fraction of the emission. A detailed investigation indicates that ~50%-67% of the emission might go undetected, which could make our limit consistent with that of Rephaeli & Gruber and Fusco-Femiano et al. The thermal interpretation of the hard Coma spectrum is consistent with recent analyses of INTEGRAL and Swift data.

Daniel R. Wik; Craig L. Sarazin; Alexis Finoguenov; Kyoko Matsushita; Kazuhiro Nakazawa; Tracy E. Clarke

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Hard-x-ray microscopy with Fresnel zone plates reaches 40 nm Rayleigh resolution  

SciTech Connect (OSTI)

Substantial improvements in the nanofabrication and characteristics of gold Fresnel zone plates yielded unprecedented resolution levels in hard-x-ray microscopy. Tests performed on a variety of specimens with 8-10 keV photons demonstrated a first-order lateral resolution below 40 nm based on the Rayleigh criterion. Combined with the use of a phase contrast technique, this makes it possible to view features in the 30 nm range; good-quality images can be obtained at video rate, down to 50 ms/frame. The important repercussions on materials science, nanotechnology, and the life sciences are discussed.

Chu, Y. S.; Yi, J. M.; De Carlo, F.; Shen, Q.; Lee, Wah-Keat [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Wu, H. J.; Wang, C. L.; Wang, J. Y.; Liu, C. J.; Wang, C. H. [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Wu, S. R.; Chien, C. C. [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Department of Engineering Science and System, National Tsing Hua University, Hsinchu 300, Taiwan (China); Hwu, Y. [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Department of Engineering Science and System, National Tsing Hua University, Hsinchu 300, Taiwan (China); Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan (China); National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Tkachuk, A.; Yun, W.; Feser, M. [Xradia Inc., 5052 Commercial Circle, Concord, California 94520 (United States); Liang, K. S. [National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Yang, C. S. [Center for Nanomedicine, National Health Research Institutes, Miaoli 350, Taiwan (China); Je, J. H. [X-ray Imaging Center, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Margaritondo, G. [Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2008-03-10T23:59:59.000Z

82

Concepts and performance for a next-generation storage ring hard x-ray source  

SciTech Connect (OSTI)

Among the possibilities for a next-generation hard x-ray source is a so-called 'ultimate storage ring'. This refers to a large, high-energy storage ring with very low emittance and high current. Such a ring has the potential to deliver significantly higher spectral brightness and transverse coherence than present third-generation rings. At the same time, it promises the stability and reliability that users have come to expect in a light source. In this paper, we present a design for a 7-GeV, 40-sector storage ring with a circumference of 3.1 km and an emittance of 15 pm in both planes.

Borland, M. [Argonne National Laboratory, Argonne, IL, 60439 (United States)

2010-06-23T23:59:59.000Z

83

Spectral Characteristics of the Hard X Ray Emission from a Plasma Focus Device  

Science Journals Connector (OSTI)

An indirect method to infer the spectra based on the measurement of the beam intensity transmission through different metallic samples is described in this communication. A Plasma Focus device (5.67 kJ 30 kV) was studied as a pulsed hard x ray source operated with deuterium at a filling pressure in the range of 3 to 5 mbar. Relevant spectral components belonging to the 50 – 150 keV range with a single maximum located in the 75 – 85 keV region were obtained for the radiation coming out of the Plasma Focus chamber which is made of stainless steel.

V. Raspa; L. Sigaut; R. Vieytes; A. Clausse; C. Moreno

2006-01-01T23:59:59.000Z

84

Achieving Vibration Stability of the NSLS-II Hard X-ray Nanoprobe Beamline  

SciTech Connect (OSTI)

The hard x-ray nanoprobe (HXN) beamline of the National Synchrotron Light Source II (NSLS-II) requires high levels of stability in order to achieve the desired instrument resolution. To ensure that the design of the endstation helps meet the stringent criteria and that natural and cultural vibration is mitigated both passively and actively, a comprehensive study complimentary to the design process has been undertaken. Vibration sources that have the potential to disrupt sensitive experiments such as wind, traffic, and NSLS II operating systems have been studied using state-of-the-art simulations and an array of field data. Further, final stage vibration isolation principles have been explored.

Simos, N.; Chu, Y. S.; Broadbent, A.; Nazaretski, E.; Margulies, L.; Dyling, O.; Shen, Q.; Fallier, M. [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2011-09-09T23:59:59.000Z

85

An UHV apparatus for X-ray resonant magnetic reflectivity in the hard X-ray range  

SciTech Connect (OSTI)

We present the development of a novel UHV compact reflectometer designed and developed for the investigation of magnetic properties of thin films at the ID12-E.S.R.F. beamline. This new instrument is dedicated to x-ray resonant magnetic reflectivity experiment from thin film or multilayered sample. We present the principles of this versatile and simple instrument. We report also the results of resonant magnetic reflectivity experiments carried out for the Fe/Ir multilayers. This will demonstrate the capability to record either angle or energy dependent measurements at the L edges of Ir simultaneously to the XMCD spectra.

Jaouen, N.; Wilhelm, F.; Rogalev, A.; Goulon, J. [European Synchrotron Radiation Facility, BP220, F-38043 Grenoble (France); Tonnerre, J.M. [Laboratoire de Cristallographie, CNRS, BP166, F-38042 Grenoble (France)

2004-05-12T23:59:59.000Z

86

Analysis of the optical design of the NSLS-II Coherent Hard X-ray beamline  

SciTech Connect (OSTI)

Ultra-low emittance third-generation synchrotron radiation sources such as the NSLS-II offer excellent opportunities for the development of experimental techniques exploiting x-ray coherence. Coherent light scattered by a heterogeneous sample produces a speckle pattern characteristic for the specific arrangement of the scatterers. This may vary over time, and the resultant intensity fluctuations can be measured and analyzed to provide information about the sample dynamics. X-ray photon correlation spectroscopy (XPCS) extends the capability of dynamic light scattering to opaque and turbid samples and extends the measurements of time evolution to nanometer length scales. As a consequence XPCS became crucial in the study of dynamics in systems including, but not being limited to, colloids, polymers, complex fluids, surfaces and interfaces, phase ordering alloys, etc. In this paper we present the conceptual optical design and the theoretical performance of the Coherent Hard X-ray (CHX) beamline at NSLS-II, dedicated to XPCS and other coherent scattering techniques. For the optical design of this beamline, there is a tradeoff between the coherence needed to distinguish individual speckles and the phase acceptance (high intensity) required to measure fast dynamics with an adequate signal-to-noise level. As XPCS is a 'photon hungry' technique, the beamline optimization requires maximizing the signal-to-noise ratio of the measured intensity-intensity autocorrelation function. The degree of coherence, as measured by a two-slit (Young) experiment, is used to characterize the speckle pattern visibilities. The beamline optimization strategy consists of maximization of the on-sample intensity while keeping the degree of coherence within the 0.1-0.5 range. The resulted design deviates substantially from an ad-hoc modification of a hard x-ray beamline for XPCS measurements. The CHX beamline will permit studies of complex systems and measurements of bulk dynamics down to the microsecond time scales. In general, the 10-fold increase in brightness of the NSLS-II, compared to other sources, will allow for measurements of dynamics on time-scales that are two orders of magnitude faster than what is currently possible. We also conclude that the common approximations used in evaluating the transverse coherence length would not be sufficiently accurate for the calculation of the coherent properties of an undulator-based beamline, and a thorough beamline optimization at a low-emittance source such as the NSLS-II requires a realistic wave-front propagation analysis.

Fluerasu A.; Chubar, O.; Kaznatcheev, K.; Baltser, J.; Wiegart, Lutz; Evans-Lutterodt, K.; Carlucci-Dayton, M.; Berman, L.

2011-08-21T23:59:59.000Z

87

The hard X-ray spectrum of Compton-thick Seyfert 2 galaxies and the synthesis of the XRB  

E-Print Network [OSTI]

A synthesis model for the cosmic X-ray Background (XRB) is presented, which includes a proper treatment of Compton scattering in the absorbing matter for type 2 AGN. Evidence for a decrease of the relative importance of type 2 AGN at high redshift is found, which may be due either to a decrease of the relative number of obscured sources, or (more plausibly) to an increase of the fraction of Compton-thick absorbed sources. The XRB spectrum, soft X-rays and hard X-rays source counts can be simultaneously fitted only if the XRB normalization as derived from BeppoSAX/MECS measurements is adopted.

Giorgio Matt; Fulvio Pompilio; Fabio La Franca

1999-12-16T23:59:59.000Z

88

Study of hard disk and slider surfaces using X-ray photoemission electron microscopy and near-edge X-ray absorption fine structure spectroscopy  

SciTech Connect (OSTI)

X-ray Photo Emission Electron Microscopy (X-PEEM) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy were applied to study the properties of amorphous hard carbon overcoats on disks and sliders, and the properties of the lubricant. The modification of lubricants after performing thermal desorption studies was measured by NEXAFS, and the results are compared to the thermal desorption data. The study of lubricant degradation in wear tracks is described. Sliders were investigated before and after wear test, and the modification of the slider coating as well as the transfer of lubricant to the slider was studied. The studies show that the lubricant is altered chemically during the wear. Fluorine is removed and carboxyl groups are formed.

Anders, S.; Stammler, T. [Lawrence Berkeley National lab., CA (United States). Advanced Light Source Div.; Bhatia, C.S. [SSD/IBM, San Jose, CA (United States); Stoehr, J. [IBM Research Div., San Jose, CA (United States). Almaden Research Center; Fong, W.; Chen, C.Y.; Bogy, D.B. [Univ. of California, Berkeley, CA (United States)

1998-04-01T23:59:59.000Z

89

PUBLISHED ONLINE: 17 JANUARY 2010 | DOI: 10.1038/NPHYS1506 High-reflectivity high-resolution X-ray crystal  

E-Print Network [OSTI]

of X-ray free-electron laser oscillators (XFELOs), next-generation hard-X-ray sources of the highest-resolution X-ray crystal optics with diamonds Yuri V. Shvyd'ko1 *, Stanislav Stoupin1 , Alessandro Cunsolo1,2 , Ayman H. Said1 and Xianrong Huang2 Owing to the depth to which hard X-rays penetrate into most materials

Loss, Daniel

90

Lensless X-Ray Imaging in Reflection  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Lensless X-Ray Imaging in Reflection Lensless X-Ray Imaging in Reflection Print Wednesday, 26 October 2011 00:00 The advent of x-ray free-electron laser (XFEL) light sources has...

91

Wide Field Hard X-ray Survey Telescope: ProtoEXIST1  

E-Print Network [OSTI]

We report our progress on the development of pixellated imaging CZT detector arrays for our first-generation balloon-borne wide-field hard X-ray (20 - 600 keV) telescope, ProtoEXIST1. Our ProtoEXIST program is a pathfinder for the High Energy Telescope (HET) on the Energetic X-ray Imaging Survey telescope (EXIST), a proposed implementation of the Black Hole Finder Probe. ProtoEXIST1 consists of four independent coded-aperture telescopes with close-tiled (~0.4 mm gaps) CZT detectors that preserve their 2.5mm pixel pitch. Multiple shielding/field-of-view configurations are planned to identify optimal geometry for the HET in EXIST. The primary technical challenge in ProtoEXIST is the development of large area, close-tiled modules of imaging CZT detectors (1000 cm2 for ProtoEXIST1), with all readout and control systems for the ASIC readout vertically stacked. We describe the overall telescope configuration of ProtoEXIST1 and review the current development status of the CZT detectors, from individual detector crys...

Hong, J; Chammas, N; Allen, B; Copete, A; Said, B; Burke, M; Howell, J; Gauron, T; Baker, R G; Barthelmy, S D; Sheikh, S; Gehrels, N; Cook, W R; Burnham, J A; Harrison, F A; Collins, J; Labov, S; Garson, A; Krawczynski, H

2007-01-01T23:59:59.000Z

92

Hard X-ray emission from accretion shocks around galaxy clusters  

Science Journals Connector (OSTI)

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is consistent with a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the model, and the observed HXR luminosity is consistent with the fraction of shock thermal energy deposited in relativistic electrons being 0.1. Alternative models, where the HXR emission is predicted to be correlated with the cluster thermal emission, are disfavored by the data. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) ?-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed.

Doron Kushnir; Eli Waxman

2010-01-01T23:59:59.000Z

93

Hard X-ray emission from accretion shocks around galaxy clusters  

SciTech Connect (OSTI)

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is consistent with a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the model, and the observed HXR luminosity is consistent with the fraction of shock thermal energy deposited in relativistic electrons being ?<0.1. Alternative models, where the HXR emission is predicted to be correlated with the cluster thermal emission, are disfavored by the data. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) ?-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed.

Kushnir, Doron; Waxman, Eli, E-mail: doron.kushnir@weizmann.ac.il, E-mail: eli.waxman@weizmann.ac.il [Physics Faculty, Weizmann Institute of Science, PO Box 26, Rehovot (Israel)

2010-02-01T23:59:59.000Z

94

Solar Hard X-ray Source Sizes in a Beam-Heated and Ionised Chromosphere  

E-Print Network [OSTI]

Solar flare hard X-rays (HXRs) are produced as bremsstrahlung when an accelerated population of electrons interacts with the dense chromospheric plasma. HXR observations presented by using the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) have shown that HXR source sizes are 3-6 times more extended in height than those predicted by the standard collisional thick target model (CTTM). Several possible explanations have been put forward including the multi-threaded nature of flare loops, pitch-angle scattering, and magnetic mirroring. However, the nonuniform ionisation (NUI) structure along the path of the electron beam has not been fully explored as a solution to this problem. Ionised plasma is known to be less effective at producing nonthermal bremsstrahlung HXRs when compared to neutral plasma. If the peak HXR emission was produced in a locally ionised region within the chromosphere, the intensity of emission will be preferentially reduced around this peak, resulting in a more extended source. Due to...

O'Flannagain, A; Gallagher, P T

2014-01-01T23:59:59.000Z

95

Achieving Vibration Stability of the NSLS-II Hard X-ray Nanoprobe Beamline  

SciTech Connect (OSTI)

The Hard X-ray Nanoprobe (HXN) Beamline of National Synchrotron Light Source II (NSLS-lI) requires high levels of stability in order to achieve the desired instrument resolution. To ensure that the design of the endstation helps meet the stringent criteria and that natural and cultural vibration is mitigated both passively and actively, a comprehensive study complimentary to the design process has been undertaken. Vibration sources that have the potential to disrupt sensitive experiments such as wind, traffic and NSLS II operating systems have been studied using state of the art simulations and an array of field data. Further, final stage vibration isolation principles have been explored in order to be utilized in supporting endstation instruments. This paper presents results of the various study aspects and their influence on the HXN design optimization.

Simos, N.; Chu, Y. N.; Broadbent, A.; Nazaretski, E.; Margulies, L.; Dyling, O.; Shen, Q.; Fallier, M.

2010-08-30T23:59:59.000Z

96

Integral detection of hard X-ray emission from the Galactic nuclear region  

E-Print Network [OSTI]

This letter presents the first results of an observational campaign to study the Galactic Centre with INTEGRAL. The mosaicked images obtained with the IBIS/ISGRI coded aperture instrument in the energy ranges 20-40 and 40-100 keV, give a yet unseen view of the high-energy sources of this region in hard X- and gamma-rays with an angular resolution of 12 arcmin (FWHM). We report on the discovery of a source, IGR J17456-2901, coincident with the Galactic Nucleus SgrA* to within 0.9 arcmin. Located at R.A.(J2000.0) = 17h45m38.5s, Dec.(J2000.0) = -29:01:15, the source is visible up to about 100 keV with a 20-100 keV luminosity at 8 kpc of (2.89 +/- 0.41) x 10^35 ergs/s. Although the new INTEGRAL source cannot unequivocally be associated to the Galactic Nucleus, this is the first report of significant hard X-ray emission from within the inner 10 arcming of the Galaxy and a contribution from the galactic supermassive black hole itself cannot be excluded.

Bélanger, G; Goldoni, P; Paul, J; Terrier, R; Falanga, M; Ubertini, P; Bazano, A; Santo, M D; Winkler, C; Parmar, A N; Kuulkers, E; Ebisawa, K; Roques, J P; Lund, N; Melia, F

2004-01-01T23:59:59.000Z

97

Ultra hard x rays from krypton clusters heated by intense laser fields R. C. Issac,a)  

E-Print Network [OSTI]

drives a fast ignition wave.15 Prop- erties of the cluster media as well as the incident laser paUltra hard x rays from krypton clusters heated by intense laser fields R. C. Issac,a) G. Vieux, B of ultrashort laser pulses with krypton clusters at intensity up to 1.3 1018 Wcm 2 has been investigated

Strathclyde, University of

98

Contribution of synchrotron radiation to small-angle X-ray scattering studies in hard condensed matter  

Science Journals Connector (OSTI)

Synchrotron radiation, by virtue of its special beam characteristics, has revived interest in small-angle X-ray scattering for hard condensed matter and materials science. New techniques have been developed and new scientific themes tackled, ranging from metallurgy to nanotechnology.

Simon, J.-P.

2007-01-20T23:59:59.000Z

99

Experimental study on hard X-rays emitted from metre-scale negative discharges in air  

E-Print Network [OSTI]

We investigate the development of meter long negative discharges and focus on their X-ray emissions. We describe appearance, timing and spatial distribution of the X-rays. They appear in bursts of nanosecond duration mostly in the cathode area. The spectrum can be characterized by an exponential function with 200 keV characteristic photon energy. With nanosecond-fast photography we took detailed images of the pre-breakdown phenomena during the time when X-rays were registered. We found bipolar discharge structures, also called "pilot systems", in the vicinity of the cathode. As in our previous study of X-rays from positive discharges, we correlate the X-ray emission with encounters between positive and negative streamers. We suggest that a similar process is responsible for X-rays generated by lightning leaders.

Kochkin, P O; Ebert, Ute

2015-01-01T23:59:59.000Z

100

Galaxy Clusters in the Swift/Burst Alert Telescope Era: Hard X-rays in the Intracluster Medium  

Science Journals Connector (OSTI)

We report the detection of 10 clusters of galaxies in the ongoing Swift/Burst Alert Telescope (BAT) all-sky survey. This sample, which mostly comprises merging clusters, was serendipitously detected in the 15-55 keV band. We use the BAT sample to investigate the presence of excess hard X-rays above the thermal emission. The BAT clusters do not show significant (e.g., ?2?) nonthermal hard X-ray emission. The only exception is represented by Perseus whose high-energy emission is likely due to NGC 1275. Using XMM-Newton, Swift/XRT, Chandra and BAT data, we are able to produce upper limits of the inverse Compton (IC) emission mechanism which are in disagreement with most of the previously-claimed hard X-ray excesses. The coupling of the X-ray upper limits of the IC mechanism to radio data shows that, in some clusters, the magnetic field might be larger than 0.5 ?G. We also derive the first log N-log S and luminosity function distributions of galaxy clusters above 15 keV.

M. Ajello; P. Rebusco; N. Cappelluti; O. Reimer; H. Böhringer; J. Greiner; N. Gehrels; J. Tueller; A. Moretti

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
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101

Measurements of hard x-ray emission from runaway electrons in DIII-D  

SciTech Connect (OSTI)

The spatial distribution of runaway electron (RE) strikes to the wall during argon pellet-initiated rapid shutdown of diverted and limited plasma shapes in DIII-D is studied using a new array of hard x-ray (HXR) scintillators. Two plasma configurations were investigated: an elongated diverted H-mode and a low-elongation limited L-mode. HXR emission from MeV level REs generated during the argon pellet injection is observed during the thermal quench (TQ) in diverted discharges from REs lost into the divertor. In limiter discharges, this prompt TQ loss is reduced, suggesting improved TQ confinement of REs in this configuration. During the plateau phase when the plasma current is carried by REs, toroidally symmetric HXR emission from remaining confined REs is seen. Transient HXR bursts during this RE current plateau suggest the presence of a small level of wall losses due to the presence of an unidentified instability. Eventually, an abrupt final loss of the remaining RE current occurs. This final loss HXR emission shows a strong toroidal peaking and a consistent spatiotemporal evolution that suggests the development of a kink instability.

James, A. N. [University of California, San Diego; Austin, M. E. [University of Texas, Austin; Eidietis, N. W. [General Atomics, San Diego; Evans, T.E. [General Atomics, San Diego; Jernigan, T. C. [Oak Ridge National Laboratory (ORNL)

2012-01-01T23:59:59.000Z

102

KAPPA DISTRIBUTION MODEL FOR HARD X-RAY CORONAL SOURCES OF SOLAR FLARES  

SciTech Connect (OSTI)

Solar flares produce hard X-ray emission, the photon spectrum of which is often represented by a combination of thermal and power-law distributions. However, the estimates of the number and total energy of non-thermal electrons are sensitive to the determination of the power-law cutoff energy. Here, we revisit an 'above-the-loop' coronal source observed by RHESSI on 2007 December 31 and show that a kappa distribution model can also be used to fit its spectrum. Because the kappa distribution has a Maxwellian-like core in addition to a high-energy power-law tail, the emission measure and temperature of the instantaneous electrons can be derived without assuming the cutoff energy. Moreover, the non-thermal fractions of electron number/energy densities can be uniquely estimated because they are functions of only the power-law index. With the kappa distribution model, we estimated that the total electron density of the coronal source region was {approx}2.4 Multiplication-Sign 10{sup 10} cm{sup -3}. We also estimated without assuming the source volume that a moderate fraction ({approx}20%) of electrons in the source region was non-thermal and carried {approx}52% of the total electron energy. The temperature was 28 MK, and the power-law index {delta} of the electron density distribution was -4.3. These results are compared to the conventional power-law models with and without a thermal core component.

Oka, M.; Ishikawa, S.; Saint-Hilaire, P.; Krucker, S.; Lin, R. P. [Space Sciences Laboratory, University of California Berkeley (United States)] [Space Sciences Laboratory, University of California Berkeley (United States)

2013-02-10T23:59:59.000Z

103

Radiation Pressure Supported AGN Tori with Hard X-Ray and Stellar Heating  

E-Print Network [OSTI]

The dynamics and structure of toroidal obscuration around AGN remain uncertain and controversial. In this paper we extend earlier work on the dynamical role of infrared radiation pressure by adding the effects of two kinds of distributed heating: Compton-heating due to hard X-rays from the nucleus and local starlight heating. We find numerical solutions to the axisymmetric hydrostatic equilibrium, energy balance, and photon diffusion equations including these effects. Within the regime of typical parameters, the two different sources of additional heating have very similar effects: the density profile within the torus becomes shallower both radially and vertically, but for plausible heating rates, there is only minor change (relative to the source-free case) in the distribution of column density with solid angle. The most interesting consequence of distributed heating is that it selects out a relatively narrow range of parameters permitting an equilibrium, particularly $(L/L_E)/\\tau_T$. We discuss the implications of both the narrowness of the permitted range and its approximate coincidence with the range inferred from observations.

Jiming Shi; Julian H. Krolik

2008-02-13T23:59:59.000Z

104

Balloon-borne hard X-ray polarimetry with PoGOLite  

E-Print Network [OSTI]

PoGOLite is a hard X-ray polarimeter operating in the 25-100 keV energy band. The instrument design is optimised for the observation of compact astrophysical sources. Observations are conducted from a stabilised stratospheric balloon platform at an altitude of approximately 40 km. The primary targets for first balloon flights of a reduced effective area instrument are the Crab and Cygnus-X1. The polarisation of incoming photons is determined using coincident Compton scattering and photo-absorption events reconstructed in an array of plastic scintillator detector cells surrounded by a bismuth germanate oxide (BGO) side anticoincidence shield and a polyethylene neutron shield. A custom attitude control system keeps the polarimeter field-of-view aligned to targets of interest, compensating for sidereal motion and perturbations such as torsional forces in the balloon rigging. An overview of the PoGOLite project is presented and the outcome of the ill-fated maiden balloon flight is discussed.

,

2012-01-01T23:59:59.000Z

105

An in-vacuum wiggler for SOLEIL Hard X-rays spectral range  

SciTech Connect (OSTI)

The production of Hard X-rays has become a tricky problem on medium energy storage rings. It requires Insertion Devices (IDs) with high magnetic field and a large number of periods. To cover the 20-50 keV photon energy range at SOLEIL (2.75 GeV), an in-vacuum wiggler (WSV50) has been preferred to a superconducting ID. The wiggler is composed of 38 periods of 50 mm producing a 2.1 T field at a minimum magnetic gap of 5.5 mm. To minimize the magnetic forces acting between magnet arrays (8.5 tons), a compensation system composed of non magnetic springs has been mounted apart from the magnet system to reduce the mechanical deformations. The wiggler has been assembled step by step by means of a genetic algorithm which minimizes the magnetic errors measured with a flipping coil. This paper presents the mechanical and magnetic design of the wiggler as well as the construction and the magnetic measurements.

Marcouille, O.; Chapuis, L.; Brunelle, P.; Berteaud, P.; Couprie, M.-E.; Filhol, J.-M.; Herbeaux, C.; Marlats, J.-L.; Massal, M.; Mary, A.; Tavakoli, K.; Valleau, M.; Veteran, J. [Synchrotron SOLEIL, L'Orme des Merisiers, Bat. A, Saint-Aubin, Gif-sur-Yvette- 9119 (France)

2010-06-23T23:59:59.000Z

106

The variable hard X-ray emission of NGC4945 as observed by NuSTAR  

E-Print Network [OSTI]

We present a broadband (~0.5-79 keV) spectral and temporal analysis of multiple NuSTAR observations combined with archival Suzaku and Chandra data of NGC4945, the brightest extragalactic source at 100 keV. We observe hard X-ray (> 10 keV) flux and spectral variability, with flux variations of a factor 2 on timescales of 20 ksec. A variable primary continuum dominates the high energy spectrum (>10 keV) in all the states, while the reflected/scattered flux which dominates at Etransmission spectrum we derive a Compton depth along the line of sight of tau_Thomson ~ 2.9, and a global covering factor for the circumnuclear gas of ~ 0.15. This agrees with the constraints derived from the high energy variability, which implies that most of the high energy flux is transmitted, rather that Compton-scattered. This demonstrates the effectiveness of spectral analysis in constraining the geometric properties of the circumnuclear gas, and validat...

Puccetti, Simonetta; Fiore, Fabrizio; Arévalo, Patricia; Risaliti, Guido; Bauer, Franz E; Brandt, William N; Stern, Daniel; Harrison, Fiona A; Alexander, David M; Boggs, Steve E; Christensen, Finn E; Craig, William W; Gandhi, Poshak; Hailey, Charles J; Koss, Michael R; Lansbury, George B; Luo, Bin; Madejski, Greg M; Matt, Giorgio; Walton, Dominic J; Zhang, Will

2014-01-01T23:59:59.000Z

107

Simbol-X Hard X-ray Focusing Mirrors: Results Obtained During the Phase A Study  

SciTech Connect (OSTI)

Simbol-X will push grazing incidence imaging up to 80 keV, providing a strong improvement both in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. The superb hard X-ray imaging capability will be guaranteed by a mirror module of 100 electroformed Nickel shells with a multilayer reflecting coating. Here we will describe the technogical development and solutions adopted for the fabrication of the mirror module, that must guarantee an Half Energy Width (HEW) better than 20 arcsec from 0.5 up to 30 keV and a goal of 40 arcsec at 60 keV. During the phase A, terminated at the end of 2008, we have developed three engineering models with two, two and three shells, respectively. The most critical aspects in the development of the Simbol-X mirrors are i) the production of the 100 mandrels with very good surface quality within the timeline of the mission, ii) the replication of shells that must be very thin (a factor of 2 thinner than those of XMM-Newton) and still have very good image quality up to 80 keV, iii) the development of an integration process that allows us to integrate these very thin mirrors maintaining their intrinsic good image quality. The Phase A study has shown that we can fabricate the mandrels with the needed quality and that we have developed a valid integration process. The shells that we have produced so far have a quite good image quality, e.g. HEW < or approx. 30 arcsec at 30 keV, and effective area. However, we still need to make some improvements to reach the requirements. We will briefly present these results and discuss the possible improvements that we will investigate during phase B.

Tagliaferri, G.; Basso, S.; Civitani, M.; Conconi, P.; Cotroneo, V.; Pareschi, G.; Spiga, D. [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46, 23807 Merate (Italy); Borghi, G.; Garoli, D.; Mattarello, V.; Orlandi, A.; Valsecchi, G.; Vernani, D. [Media Lario Technologies S.r.l., Localita Pascolo, 23842 Bosisio Parini (Italy); Burkert, W.; Freyberg, M.; Hartner, G. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstr. 1, 85748 Garching (Germany); Citterio, O. [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46, 23807 Merate (Italy); Media Lario Technologies S.r.l., Localita Pascolo, 23842 Bosisio Parini (Italy); Gorenstein, P.; Romaine, S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2009-05-11T23:59:59.000Z

108

Accretion Properties of a Sample of Hard X-Ray (<60 keV) Selected Seyfert 1 Galaxies  

Science Journals Connector (OSTI)

We examine the accretion properties in a sample of 42 hard (3-60 keV) X-ray selected nearby broad-line active galactic nuclei (AGNs). The energy range in the sample is harder than that usually used in similar previous studies. These AGNs are mainly complied from the RXTE All Sky Survey, and complemented by the released INTEGRAL AGN catalog. The black hole masses, bolometric luminosities of AGN, and Eddington ratios are derived from their optical spectra in terms of the broad H? emission line. The tight correlation between the hard X-ray (3-20 keV) and bolometric/line luminosity is well identified in our sample. Also identified is a strong inverse Baldwin relationship of the H? emission line. In addition, all of these hard X-ray AGNs are biased toward luminous objects with a high Eddington ratio (mostly between 0.01 and 0.1) and a low column density (22 cm–2), which is most likely due to the selection effect of the surveys. The hard X-ray luminosity is consequently found to be strongly correlated with the black hole mass. We believe the sample completeness will be improved in the next few years by the ongoing Swift and the International Gamma-Ray Astrophysics Laboratory missions, and by the next advanced missions, such as NuSTAR, Simbol-X, and NeXT. Finally, the correlation between RFe (= optical Fe II/H?) and disk temperature as assessed by T ? (L/L Edd)M –1 BH leads us to suggest that the strength of the Fe II emission is mainly determined by the shape of the ionizing spectrum.

J. Wang; Y. F. Mao; J. Y. Wei

2009-01-01T23:59:59.000Z

109

Long-Working-Distance Kirkpatrick-Baez Mirrors for Hard X-ray Beamlines at SPring-8  

SciTech Connect (OSTI)

We designed and installed two types of long-working-distance Kirkpatrick-Baez (KB) mirrors and mirror manipulators, which were customized into each experiment for hard x-ray undulator beamlines at SPring-8. For the BL32XU RIKEN Targeted Proteins beamline, 400-mm-long KB focusing mirrors for a beam size of 1 {mu}m with a 730-mm-long working distance were designed for carrying out the structural analysis of protein microcrystals. We realized a focusing beam size of 0.9x0.9 {mu}m{sup 2}(FWHM) and a focusing intensity of 6x10{sup 10} (photons/s) at an x-ray energy of 12.4 keV. For the BL19LXU RIKEN SR Physics beamline, we developed KB mirrors for 100-nm focusing with a 100-mm-working distance for the purpose of nano-focus x-ray diffraction. A focusing beam size of 100x100 nm{sup 2}(FWHM) and a high focusing intensity of 3.7x10{sup 10} (photons/s) at an x-ray energy of 12.4 keV were realized.

Yumoto, H.; Koyama, T. [Japan Synchrotron Radiation Research Institute (JASRI)/SPring-8, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hirata, K.; Kawano, Y.; Ueno, G.; Nisawa, A.; Hikima, T.; Takeshita, S.; Ito, K.; Tanaka, Y.; Arima, T.; Yamamoto, M. [RIKEN/SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Ohsumi, H.; Ohashi, H.; Goto, S. [Japan Synchrotron Radiation Research Institute (JASRI)/SPring-8, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); RIKEN/SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2011-09-09T23:59:59.000Z

110

Lensless X-Ray Imaging in Reflection  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs...

111

Lensless X-Ray Imaging in Reflection  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Imaging in Reflection Print Wednesday, 26 October 2011 00:00 The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities...

112

Observation and simulation of hard x ray photoelectron diffraction to determine polarity of polycrystalline zinc oxide films with rotation domains  

SciTech Connect (OSTI)

X ray photoelectron diffraction (XPD) patterns of polar zinc oxide (ZnO) surfaces were investigated experimentally using hard x rays and monochromatized Cr K{alpha} radiation and theoretically using a cluster model approach and a dynamical Bloch wave approach. We focused on photoelectrons emitted from the Zn 2p{sub 3/2} and O 1s orbitals in the analysis. The obtained XPD patterns for the (0001) and (0001) surfaces of a ZnO single crystal were distinct for a given emitter and polarity. Polarity determination of c-axis-textured polycrystalline ZnO thin films was also achieved with the concept of XPD, even though the in-plane orientation of the columnar ZnO grains was random.

Williams, Jesse R.; Adachi, Yutaka; Ohashi, Naoki [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); NIMS Saint-Gobain Research Center of Excellence for Advanced Materials, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Pis, Igor [Synchrotron X-ray Station at SPring-8, NIMS, SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, Prague 8 18000 (Czech Republic); Kobata, Masaaki [Synchrotron X-ray Station at SPring-8, NIMS, SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Winkelmann, Aimo [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, D-06120 Halle (Saale) (Germany); Matsushita, Tomohiro [Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kobayashi, Keisuke [Synchrotron X-ray Station at SPring-8, NIMS, SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046 (Japan)

2012-02-01T23:59:59.000Z

113

An Improved Method to Derive the Lower Energy Cutoff of non-Thermal Electrons From Hard x-Rays of Solar Flares  

Science Journals Connector (OSTI)

By changing a dimensionless calculation to a dimensional one, introducing a more accurate bremsstrahlung cross section, and using a more reasonable fitting energy range, we have recalculated the hard X-ray bre...

W.Q. Gan; Y.P. Li; J. Chang; James M. Tiernan

2002-05-01T23:59:59.000Z

114

Portable chamber for the study of UHV prepared electrochemical interfaces by hard x-ray diffraction  

SciTech Connect (OSTI)

We report on a new electrochemical cell setup, combined with a portable UHV chamber, for in situ x-ray diffraction using synchrotron radiation. In contrast to more traditional electrochemical sample preparation schemes, atomically clean and well-ordered surfaces are routinely prepared by UHV methods, even in the case of reactive elements or alloys. Samples can be transferred from larger UHV systems into the portable chamber without exposure to ambient air. They can then be studied successively in UHV, in controlled gas atmospheres, and in contact with electrolyte solutions under applied electrochemical potential. The electrochemical setup employs a droplet geometry, which guarantees good electrochemical conditions during in situ x-ray measurements combined with voltammetry. We present first experimental results of Cu deposition on GaAs(001) and on freshly produced nanometric Pd(001) islands on Cu{sub 0.83}Pd{sub 0.17}(001), respectively.

Renner, Frank Uwe; Gruender, Yvonne; Zegenhagen, Joerg [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble (France)

2007-03-15T23:59:59.000Z

115

The Hard X-Ray to Gamma-ray Spectrum in the EGRET AGNs  

E-Print Network [OSTI]

EGRET (20 MeV to 30 GeV) on board the Compton GRO has observed high-energy emission from about 40-50 Active Galactic Nuclei. Theoretical models of this emission based on the upscattering of thermal disk photons by cooling, relativistic electrons can successfully account for the EGRET observations, but they predict a considerably greater X-ray flux than that actually observed in a majority of these sources. This inconsistency may be an indication that the particles are energized during the Compton scattering process, since the X-ray emission is produced by the lowest energy electrons, whose density may be relatively small due to the acceleration. Such a situation may arise as a result of resistive field generation in electromagnetic acceleration schemes, which we here explore. A key feature of this model is the assumed existence of a current associated with the azimuthal component B_phi of the underlying magnetic field by a slight imbalance in the energy distributions of outwardly moving, relativistic electrons and protons produced at the disk surface via shock acceleration. The generation of an electric field (via magnetic field line reconnection) is thus required to maintain the current in the presence of a resistivity induced by the radiative drag on the relativistic electrons. We show that the resulting spectrum can exhibit a significant deficit of X-rays compared with gamma-rays. In addition, due to the uni-directional flow of the current associated with B_phi, this model would predict that the electrons are energized relative to the protons in the outflow only on one side of the disk. They should be decelerated on the reverse side. As such, we would anticipate that any given blazar should have a ~50% probability of being gamma-bright, which appears to be consistent with the observed ratio.

Marco Fatuzzo; Fulvio Melia

1998-06-26T23:59:59.000Z

116

HARD X-RAY LAGS IN ACTIVE GALACTIC NUCLEI: TESTING THE DISTANT REVERBERATION HYPOTHESIS WITH NGC 6814  

SciTech Connect (OSTI)

We present an X-ray spectral and temporal analysis of the variable active galaxy NGC 6814, observed with Suzaku during 2011 November. Remarkably, the X-ray spectrum shows no evidence for the soft excess commonly observed amongst other active galaxies, despite its relatively low level of obscuration, and is dominated across the whole Suzaku bandpass by the intrinsic powerlaw-like continuum. Despite this, we clearly detect the presence of a low-frequency hard lag of ?1600 s between the 0.5-2.0 and 2.0-5.0 keV energy bands at greater than 6? significance, similar to those reported in the literature for a variety of other active galactic nuclei (AGNs). At these energies, any additional emission from, e.g., a very weak, undetected soft excess, or from distant reflection must contribute less than 3% of the observed countrates (at 90% confidence). Given the lack of any significant continuum emission component other than the powerlaw, we can rule out models that invoke distant reprocessing for the observed lag behavior, which must instead be associated with this continuum emission. These results are fully consistent with a propagating fluctuation origin for the low-frequency hard lags, and with the interpretation of the high-frequency soft lags—a common feature seen in the highest quality AGN data with strong soft excesses—as reverberation from the inner accretion disk.

Walton, D. J.; Harrison, F. A. [Cahill Centre for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)] [Cahill Centre for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Zoghbi, A.; Reynolds, C. S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)] [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Cackett, E. M. [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201 (United States)] [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201 (United States); Uttley, P. [Astronomical Institute Anton Pannekoek, University of Amsterdam, Postbus 94249, NL-1090 GE Amsterdam (Netherlands)] [Astronomical Institute Anton Pannekoek, University of Amsterdam, Postbus 94249, NL-1090 GE Amsterdam (Netherlands); Fabian, A. C.; Kara, E. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom)] [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Miller, J. M.; Reis, R. C. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)] [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)

2013-11-10T23:59:59.000Z

117

TEMPORAL AND SPATIAL ANALYSES OF SPECTRAL INDICES OF NONTHERMAL EMISSIONS DERIVED FROM HARD X-RAYS AND MICROWAVES  

SciTech Connect (OSTI)

We studied electron spectral indices of nonthermal emissions seen in hard X-rays (HXRs) and microwaves. We analyzed 12 flares observed by the Hard X-Ray Telescope aboard Yohkoh, Nobeyama Radio Polarimeters, and the Nobeyama Radioheliograph (NoRH), and compared the spectral indices derived from total fluxes of HXRs and microwaves. Except for four events, which have very soft HXR spectra suffering from the thermal component, these flares show a gap {Delta}{delta} between the electron spectral indices derived from HXRs {delta} {sub X} and those from microwaves {delta}{sub {mu}} ({Delta}{delta} = {delta} {sub X} - {delta}{sub {mu}}) of about 1.6. Furthermore, from the start to the peak times of the HXR bursts, the time profiles of the HXR spectral index {delta} {sub X} evolve synchronously with those of the microwave spectral index {delta}{sub {mu}}, keeping the constant gap. We also examined the spatially resolved distribution of the microwave spectral index by using NoRH data. The microwave spectral index {delta}{sub {mu}} tends to be larger, which means a softer spectrum, at HXR footpoint sources with stronger magnetic field than that at the loop tops. These results suggest that the electron spectra are bent at around several hundreds of keV, and become harder at the higher energy range that contributes the microwave gyrosynchrotron emission.

Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto, 607-8471 (Japan)] [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto, 607-8471 (Japan); Kiyohara, Junko; Takasaki, Hiroyuki [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto, 607-8471 (Japan)] [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto, 607-8471 (Japan); Narukage, Noriyuki [Institute of Space and Astronomical Science, Japan Aerospace Exploration Agency, Chuo, Sagamihara, Kanagawa, 229-8510 (Japan)] [Institute of Space and Astronomical Science, Japan Aerospace Exploration Agency, Chuo, Sagamihara, Kanagawa, 229-8510 (Japan); Yokoyama, Takaaki [Department of Earth and Planetary Science, University of Tokyo, Hongo, Bunkyo, Tokyo, 113-0033 (Japan)] [Department of Earth and Planetary Science, University of Tokyo, Hongo, Bunkyo, Tokyo, 113-0033 (Japan); Masuda, Satoshi [Solar-Terrestrial Environment Laboratory, Nagoya University, Chikusa, Nagoya, Aichi, 464-8601 (Japan)] [Solar-Terrestrial Environment Laboratory, Nagoya University, Chikusa, Nagoya, Aichi, 464-8601 (Japan); Shimojo, Masumi [National Astronomical Observatory of Japan, Mitaka, Tokyo, 181-8588 (Japan)] [National Astronomical Observatory of Japan, Mitaka, Tokyo, 181-8588 (Japan); Nakajima, Hiroshi, E-mail: asai@kwasan.kyoto-u.ac.jp [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano, 384-1305 (Japan)] [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano, 384-1305 (Japan)

2013-02-15T23:59:59.000Z

118

Regularized energy-dependent solar flare hard x-ray spectral index  

E-Print Network [OSTI]

The deduction from solar flare X-ray photon spectroscopic data of the energy dependent model-independent spectral index is considered as an inverse problem. Using the well developed regularization approach we analyze the energy dependency of spectral index for a high resolution energy spectrum provided by Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The regularization technique produces much smoother derivatives while avoiding additional errors typical of finite differences. It is shown that observations imply a spectral index varying significantly with energy, in a way that also varies with time as the flare progresses. The implications of these findings are discussed in the solar flare context.

Eduard P. Kontar; Alexander L. MacKinnon

2005-06-05T23:59:59.000Z

119

On the hard X-ray spectra of radio-loud active galaxies  

E-Print Network [OSTI]

Over the last few years X-ray observations of broad-line radio galaxies (BLRGs) by ASCA, RXTE and BeppoSAX have shown that these objects seem to exhibit weaker X-ray reflection features (such as the iron K\\alpha line) than radio-quiet Seyferts. This has lead to speculation that the optically-thick accretion disc in radio-loud active galactic nuclei (AGN) may be truncated to an optically-thin flow in the inner regions of the source. Here, we propose that the weak reflection features are a result of reprocessing in an ionized accretion disc. This would alleviate the need for a change in accretion geometry in these sources. Calculations of reflection spectra from an ionized disc for situations expected in radio-loud AGN (high accretion rate, moderate-to-high black hole mass) predict weak reprocessing features. This idea was tested by fitting the ASCA spectrum of the bright BLRG 3C 120 with the constant density ionized disc models of Ross & Fabian. A good fit was found with an ionization parameter of \\xi ~4000 erg cm s^{-1} and the reflection fraction fixed at unity. If observations of BLRGs by XMM-Newton show evidence for ionized reflection then this would support the idea that a high accretion rate is likely required to launch powerful radio jets.

D. R. Ballantyne; R. R. Ross; A. C. Fabian

2002-01-24T23:59:59.000Z

120

Plasma heating in solar flares and their soft and hard X-ray emissions  

E-Print Network [OSTI]

In this paper, the energy budgets of two single-loop like flares observed in X- ray are analysed under the assumption that non-thermal electrons (NTEs) are the only source of plasma heating during all phases of both events. The flares were observed by RHESSI and GOES on February 20th, 2002 and June 2nd, 2002, respectively. Using a 1D hydrodynamic code for both flares the energy deposited in the chromosphere was derived applying RHESSI observational data. The use of the Fokker-Planck formalism permits the calculation of distributions of the NTEs in flaring loops, thus spatial distributions of the X-ray non-thermal emissions and integral fluxes for the selected energy ranges which were compared with the observed ones. The best compatibility of the model with the observations was obtained for the June 2nd, 2002 event in both the 0.5-4 A GOES range and total fluxes in the 6-12 keV, 12-25 keV, 20-25 keV and 50- 100 keV energy bands. Results of photometry of the individual flaring structures in a high energy range ...

Falewicz, R

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
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121

Hard X-ray Fluorescence Measurements of Heteroepitaxial Solid Oxide Fuel Cell Cathode Materials  

SciTech Connect (OSTI)

Commonly, SOFCs are operated at high temperatures (above 800°C). At these temperatures expensive housing is needed to contain an operating stack as well as coatings to contain the oxidation of the metallic interconnects. Lowering the temperature of an operating device would allow for more conventional materials to be used, thus lowering overall cost. Understanding the surface chemical states of cations in the surface of the SOFC cathode is vital to designing a system that will perform well at lower temperatures. The samples studied were grown by pulsed laser deposition (PLD) at the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). 20% strontium doped lanthanum manganite (LSM-20) was grown on YSZ and NGO (neodymium gallate). The films on YSZ have a fiber texture. LSM-20 on NGO is heteroepitaxial. Lanthanum strontium cobalt ferrite (LSCF-6428) films were grown on LAO and YSZ with a GDC barrier layer. Total X-ray Reflection Fluorescence (TXRF) was used to depth profile the samples. In a typical experiment, the angle of the incident beam is varied though the critical angle. Below the critical angle, the x-ray decays as an evanescent wave and will only penetrate the top few nanometers. TXRF experiments done on LSM films have suggested strontium segregates to the surface and form strontium enriched nanoparticles (1). It should be pointed out that past studies have focused on 30% strontium A-site doping, but this project uses 20% strontium doped lanthanum manganite. XANES and EXAFS data were taken as a function of incoming angle to probe composition as a function of depth. XANES spectra can be difficult to analyze fully. For other materials density functional theory calculations compared to near edge measurements have been a good way to understand the 3d valence electrons (2).

Davis, Jacob N.; Miara, Lincoln J.; Saraf, Laxmikant V.; Kaspar, Tiffany C.; Gopalan, Srikanth; Pal, Uday B.; Woicik, Joseph C.; Basu, Soumendra N.; Ludwig, Karl F.

2012-12-01T23:59:59.000Z

122

Nonlinear X-ray Compton Scattering  

E-Print Network [OSTI]

X-ray scattering is a weak linear probe of matter. It is primarily sensitive to the position of electrons and their momentum distribution. Elastic X-ray scattering forms the basis of atomic structural determination while inelastic Compton scattering is often used as a spectroscopic probe of both single-particle excitations and collective modes. X-ray free-electron lasers (XFELs) are unique tools for studying matter on its natural time and length scales due to their bright and coherent ultrashort pulses. However, in the focus of an XFEL the assumption of a weak linear probe breaks down, and nonlinear light-matter interactions can become ubiquitous. The field can be sufficiently high that even non-resonant multiphoton interactions at hard X-rays wavelengths become relevant. Here we report the observation of one of the most fundamental nonlinear X-ray-matter interactions, the simultaneous Compton scattering of two identical photons producing a single photon at nearly twice the photon energy. We measure scattered...

Fuchs, Matthias; Chen, Jian; Ghimire, Shambhu; Shwartz, Sharon; Kozina, Michael; Jiang, Mason; Henighan, Thomas; Bray, Crystal; Ndabashimiye, Georges; Bucksbaum, P H; Feng, Yiping; Herrmann, Sven; Carini, Gabriella; Pines, Jack; Hart, Philip; Kenney, Christopher; Guillet, Serge; Boutet, Sebastien; Williams, Garth; Messerschmidt, Marc; Seibert, Marvin; Moeller, Stefan; Hastings, Jerome B; Reis, David A

2015-01-01T23:59:59.000Z

123

{sup 44}Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X  

SciTech Connect (OSTI)

Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: {sup 44}Ti{gamma}-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

Renaud, M.; Terrier, R.; Lebrun, F. [Laboratoire APC, CNRS-UMR 7164, Universite Paris 7, 10, rue A. Domon et Leonie Duquet, 75025 Paris Cedex 13 (France); Trap, G. [CEA/DSM/IRFU/SAp, L'Orme des Merisiers, 91191 Gif-sur-Yvette (France); Laboratoire APC, CNRS-UMR 7164, Universite Paris 7, 10, rue A. Domon et Leonie Duquet, 75025 Paris Cedex 13 (France); Decourchelle, A. [CEA/DSM/IRFU/SAp, L'Orme des Merisiers, 91191 Gif-sur-Yvette (France); Vink, J. [University Utrecht, P.O. Box 80000, NL-3508 TA, Utrecht (Netherlands)

2009-05-11T23:59:59.000Z

124

Electronic structure of Al- and Ga-doped ZnO films studied by hard X-ray photoelectron spectroscopy  

SciTech Connect (OSTI)

Al- and Ga-doped sputtered ZnO films (AZO, GZO) are semiconducting and metallic, respectively, despite the same electronic valence structure of the dopants. Using hard X-ray photoelectron spectroscopy we observe that both dopants induce a band in the electronic structure near the Fermi level, accompanied by a narrowing of the Zn 3d/O 2p gap in the valence band and, in the case of GZO, a substantial shift in the Zn 3d. Ga occupies substitutional sites, whereas Al dopants are in both substitutional and interstitial sites. The latter could induce O and Zn defects, which act as acceptors explaining the semiconducting character of AZO and the lack of variation in the optical gap. By contrast, mainly substitutional doping is consistent with the metallic-like behavior of GZO.

Gabás, M.; Ramos Barrado, José R. [Lab. de Materiales and Superficies, Dpto. de Física Aplicada I, Universidad de Málaga, 29071 Málaga (Spain); Torelli, P. [Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, I-34149 Trieste (Italy); Barrett, N. T. [CEA, DSM/IRAMIS/SPCSI, F-91191 Gif-sur-Yvette Cedex (France); Sacchi, M. [Synchrotron SOLEIL, BP 48, 91192 Gif-sur-Yvette, France and Institut des NanoSciences de Paris, UPMC Paris 06, CNRS UMR 7588, 4 Place Jussieu, 75005 Paris (France)

2014-01-01T23:59:59.000Z

125

EXTENDED HARD X-RAY EMISSION FROM THE VELA PULSAR WIND NEBULA  

SciTech Connect (OSTI)

The nebula powered by the Vela pulsar is one of the best examples of an evolved pulsar wind nebula, allowing access to the particle injection history and the interaction with the supernova ejecta. We report on the INTEGRAL discovery of extended emission above 18 keV from the Vela nebula. The northern side has no known counterparts and it appears larger and more significant than the southern one, which is in turn partially coincident with the cocoon, the soft X-ray, and TeV filament toward the center of the remnant. We also present the spectrum of the Vela nebula in the 18-400 keV energy range as measured by IBIS/ISGRI and SPI on board the INTEGRAL satellite. The apparent discrepancy between IBIS/ISGRI, SPI, and previous measurements is understood in terms of the point-spread function, supporting the hypothesis of a nebula more diffuse than previously thought. A break at {approx}25 keV is found in the spectrum within 6' from the pulsar after including the Suzaku XIS data. Interpreted as a cooling break, this points out that the inner nebula is composed of electrons injected in the last {approx}2000 years. Broadband modeling also implies a magnetic field higher than 10 {mu}G in this region. Finally, we discuss the nature of the northern emission, which might be due to fresh particles injected after the passage of the reverse shock.

Mattana, F.; Terrier, R.; Zurita Heras, J. A. [Francois Arago Centre, APC (UMR 7164 Universite Paris Diderot, CNRS/IN2P3, CEA/DSM, Observatoire de Paris), 13 rue Watt, F-75205 Paris Cedex 13 (France); Goetz, D.; Caballero, I.; Soldi, S.; Schanne, S. [AIM (UMR 7158 CEA/DSM-CNRS-Universite Paris Diderot) Irfu/Service d'Astrophysique, F-91191 Gif-sur-Yvette (France); Bouchet, L. [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Ponti, G. [Faculty of Physical and Applied Science, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Falanga, M. [International Space Science Institute (ISSI), Hallerstrasse 6, CH-3012 Bern (Switzerland); Renaud, M., E-mail: fabio.mattana@apc.univ-paris7.fr [Laboratoire Univers et Particules de Montpellier (LUPM), Universite Montpellier II, CNRS/IN2P3 UMR 5299, F-34095 Montpellier (France)

2011-12-10T23:59:59.000Z

126

High aspect ratio hard x-ray (> 100 keV) imager to measure hot electron preheat for indirectly driven capsule implosions on the National Ignition Facility  

SciTech Connect (OSTI)

We have fielded a multi-pinhole, hard x-ray (> 100 keV) imager to measure the spatially-resolved bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. These electrons are generated in laser plasma interactions, and are a source of preheat to the deuterium-tritium fuel that could limit the compressibility required for ignition and burn. Our hard x-ray imaging measurements allow to set an upper limit to the DT fuel preheat, which we find is acceptable in current capsule implosions on the NIF.

Doppner, T; Dewald, E; Divol, L; Burns, S; Izumi, N; Kline, J; LaCaille, G; McNaney, J; Prasad, R; Thomas, C A; Glenzer, S H; Landen, O; Author, A; Author, S G; Author, T

2012-05-01T23:59:59.000Z

127

SMB, X-Ray Spectroscopy & Imaging  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Home X-Ray Spectroscopy & Imaging X-Ray Spectroscopy & Imaging SSRL has five hard X-ray Spectroscopy beamlines and three Microfocus Imaging beamlines dedicated to Biological and...

128

Elimination of self-absorption in fluorescence hard-x-ray absorption spectra P. Pfalzer, J.-P. Urbach, M. Klemm, and S. Horn  

E-Print Network [OSTI]

Elimination of self-absorption in fluorescence hard-x-ray absorption spectra P. Pfalzer, J-ray absorption spectra in situations where samples cannot be made in the required configuration. However, self-absorption-ray absorption coefficients. This procedure is used to obtain the vanadium K-edge spectrum of single crystal V2O3

Frenkel, Anatoly

129

RHESSI HARD X-RAY IMAGING SPECTROSCOPY OF EXTENDED SOURCES AND THE PHYSICAL PROPERTIES OF ELECTRON ACCELERATION REGIONS IN SOLAR FLARES  

E-Print Network [OSTI]

RHESSI HARD X-RAY IMAGING SPECTROSCOPY OF EXTENDED SOURCES AND THE PHYSICAL PROPERTIES OF ELECTRON of the acceleration region but also allows an empirical study of the physics of electron tran- sport within the source acceleration and propagation of bremsstrahlung- producing electrons in solar flares. The method involves

California at Berkeley, University of

130

Caliste 64, a new CdTe micro-camera for hard X-ray spectro-imaging  

Science Journals Connector (OSTI)

In the frame of the Simbol-X mission of hard X-ray astrophysics, a prototype of micro-camera with 64 pixels called Caliste 64 has been designed and several samples have been tested. The device integrates ultra-low-noise IDeF-X V1.1 \\{ASICs\\} from CEA and a 1 cm2 Al Schottky CdTe detector from Acrorad because of its high uniformity and spectroscopic performance. The process of hybridization, mastered by the 3D Plus company, respects space applications standards. The camera is a spectro-imager with time-tagging capability. Each photon interacting in the semiconductor is tagged with a time, a position and an energy. Time resolution is better than 100 ns rms for energy deposits greater than 20 keV, taking into account electronic noise and technological dispersal of the front-end electronics. The spectrum summed across the 64 pixels results in an energy resolution of 664 eV fwhm at 13.94 keV and 842 eV fwhm at 59.54 keV, when the detector is cooled down to ?10 °C and biased at ?500 V.

A. Meuris; O. Limousin; F. Lugiez; O. Gevin; C. Blondel; F. Pinsard; M.C. Vassal; F. Soufflet; I. Le Mer

2009-01-01T23:59:59.000Z

131

High energy resolution hard X-ray and gamma-ray imagers using CdTe diode devices  

E-Print Network [OSTI]

We developed CdTe double-sided strip detectors (DSDs or cross strip detectors) and evaluated their spectral and imaging performance for hard X-rays and gamma-rays. Though the double-sided strip configuration is suitable for imagers with a fine position resolution and a large detection area, CdTe diode DSDs with indium (In) anodes have yet to be realized due to the difficulty posed by the segmented In anodes. CdTe diode devices with aluminum (Al) anodes were recently established, followed by a CdTe device in which the Al anodes could be segmented into strips. We developed CdTe double-sided strip devices having Pt cathode strips and Al anode strips, and assembled prototype CdTe DSDs. These prototypes have a strip pitch of 400 micrometer. Signals from the strips are processed with analog ASICs (application specific integrated circuits). We have successfully performed gamma-ray imaging spectroscopy with a position resolution of 400 micrometer. Energy resolution of 1.8 keV (FWHM: full width at half maximum) was ob...

Watanabe, Shin; Aono, Hiroyuki; Takeda, Shin'ichiro; Odaka, Hirokazu; Kokubun, Motohide; Takahashi, Tadayuki; Nakazawa, Kazuhiro; Tajima, Hiroyasu; Onishi, Mitsunobu; Kuroda, Yoshikatsu

2008-01-01T23:59:59.000Z

132

Single shot spatial and temporal coherence properties of the SLAC linac coherent light source in the hard x-ray regime  

SciTech Connect (OSTI)

We measured the transverse and longitudinal coherence properties of the Linac Coherent Light Source (LCLS) at SLAC in the hard x-ray regime at 9 keV photon energy on a single shot basis. Speckle patterns recorded in the forward direction from colloidal nanoparticles yielded the transverse coherence properties of the focused LCLS beam. Speckle patterns from a gold nanopowder recorded with atomic resolution allowed us to measure the shot-to-shot variations of the spectral properties of the x-ray beam. The focused beam is in the transverse direction fully coherent with a mode number close to 1. The average number of longitudinal modes behind the Si(111) monochromator is about 14.5 and the average coherence time {tau}{sub c} = (2.0 {+-} 1.0) fs. The data suggest a mean x-ray pulse duration of (29 {+-} 14) fs behind the monochromator for (100 {+-} 14) fs long electron pulses.

Gutt, C.; Wochner, P.; Fischer, B.; Conrad, H.; Castro-Colin, M.; Lee, S.; Lehmkuhler, F.; Steinke, I.; Sprung, M.; Roseker, W.; Zhu, D.; Lemke, H.; Bogle, S.; Fuoss, P. H.; Stephenson, G. B.; Cammarata, M.; Fritz, D. M.; Robert, A.; Grubel, G. (Materials Science Division); (Deutsches Elektronen-Synchrotron); (Max-Planck-Institut fur Intelligene Systeme); (LCLS, SLAC Nat. Accelerator Lab.)

2012-01-01T23:59:59.000Z

133

On the nature of the hard X-ray sources SWIFTJ1907.3-2050, IGRJ12123-5802 and IGRJ19552+0044  

E-Print Network [OSTI]

The INTEGRAL and Swift hard X-ray surveys have identified a large number of new sources, among which many are proposed as Cataclysmic Variables (CVs). Here we present the first detailed study of three X-ray selected CVs, Swift J1907.3-2050, IGRJ12123-5802, and IGRJ19552+0044 based on XMM-Newton, Suzaku, Swift observations and ground based optical and archival nIR/IR data. Swift J1907.3-2050 is highly variable from hours to months-years at all wavelengths. No coherent X-ray pulses are detected but rather transient features. The X-ray spectrum reveals a multi-temperature optically thin plasma absorbed by complex neutral material and a soft black body component arising from a small area. These characteristics are remarkably similar to those observed in magnetic CVs. A supra-solar abundance of nitrogen could arise from nuclear processed material from the donor star. Swift J1907.3-2050 could be a peculiar magnetic CV with the second longest (20.82 h) binary period. IGRJ12123-5802 is variable in the X-rays on a tim...

Bernardini, F; Mukai, K; Falanga, M; Andruchow, I; Bonnet-Bidaud, J -M; Masetti, N; Buitrago, D H Gonzalez; Mouchet, M; Tovmassian, G

2013-01-01T23:59:59.000Z

134

Center for X-Ray Optics, 1992  

SciTech Connect (OSTI)

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

Not Available

1993-08-01T23:59:59.000Z

135

Spatially Resolving a Starburst Galaxy at Hard X-ray Energies: NuSTAR, Chandra, AND VLBA Observations of NGC 253  

E-Print Network [OSTI]

Prior to the launch of NuSTAR, it was not feasible to spatially resolve the hard (E > 10 keV) emission from galaxies beyond the Local Group. The combined NuSTAR dataset, comprised of three ~165 ks observations, allows spatial characterization of the hard X-ray emission in the galaxy NGC 253 for the first time. As a follow up to our initial study of its nuclear region, we present the first results concerning the full galaxy from simultaneous NuSTAR, Chandra, and VLBA monitoring of the local starburst galaxy NGC 253. Above ~10 keV, nearly all the emission is concentrated within 100" of the galactic center, produced almost exclusively by three nuclear sources, an off-nuclear ultraluminous X-ray source (ULX), and a pulsar candidate that we identify for the first time in these observations. We detect 21 distinct sources in energy bands up to 25 keV, mostly consisting of intermediate state black hole X-ray binaries. The global X-ray emission of the galaxy - dominated by the off-nuclear ULX and nuclear sources, whic...

Wik, Daniel R; Hornschemeier, Ann E; Yukita, Mihoko; Ptak, Andrew; Zezas, Andreas; Antoniou, Vallia; Argo, Megan K; Bechtol, Keith; Boggs, Steven; Christensen, Finn; Craig, William; Hailey, Charles; Harrison, Fiona; Krivanos, Roman; Maccarone, Thomas J; Stern, Daniel; Venters, Tonia; Zhang, William W

2014-01-01T23:59:59.000Z

136

High energy resolution hard X-ray and gamma-ray imagers using CdTe diode devices  

E-Print Network [OSTI]

We developed CdTe double-sided strip detectors (DSDs or cross strip detectors) and evaluated their spectral and imaging performance for hard X-rays and gamma-rays. Though the double-sided strip configuration is suitable for imagers with a fine position resolution and a large detection area, CdTe diode DSDs with indium (In) anodes have yet to be realized due to the difficulty posed by the segmented In anodes. CdTe diode devices with aluminum (Al) anodes were recently established, followed by a CdTe device in which the Al anodes could be segmented into strips. We developed CdTe double-sided strip devices having Pt cathode strips and Al anode strips, and assembled prototype CdTe DSDs. These prototypes have a strip pitch of 400 micrometer. Signals from the strips are processed with analog ASICs (application specific integrated circuits). We have successfully performed gamma-ray imaging spectroscopy with a position resolution of 400 micrometer. Energy resolution of 1.8 keV (FWHM: full width at half maximum) was obtained at 59.54 keV. Moreover, the possibility of improved spectral performance by utilizing the energy information of both side strips was demonstrated. We designed and fabricated a new analog ASIC, VA32TA6, for the readout of semiconductor detectors, which is also suitable for DSDs. A new feature of the ASIC is its internal ADC function. We confirmed this function and good noise performance that reaches an equivalent noise charge of 110 e- under the condition of 3-4 pF input capacitance.

Shin Watanabe; Shin-nosuke Ishikawa; Hiroyuki Aono; Shin'ichiro Takeda; Hirokazu Odaka; Motohide Kokubun; Tadayuki Takahashi; Kazuhiro Nakazawa; Hiroyasu Tajima; Mitsunobu Onishi; Yoshikatsu Kuroda

2008-11-04T23:59:59.000Z

137

Design and Start-to-End Simulation of an X-Band RF Driven Hard X-Ray FEL with LCLS Injector  

SciTech Connect (OSTI)

In this note, it is briefly discussed the accelerator design and start-to-end 3D macro particles simulation (using ELEGANT and GENESIS) of an X-band RF driven hard X-ray FEL with LCLS injector. A preliminary design and LiTrack 1D simulation studies were presented before in an older publication [1]. In numerical simulations this X-band RF driven hard X-ray FEL achieves/exceeds LCLS-like performance in a much shorter overall length of 350 m, compared with 1200 m in the LCLS case. One key feature of this design is that it may achieve a higher final beam current of 5 kA plus a uniform energy profile, mainly due to the employment of stronger longitudinal wake fields in the last X-band RF linac [2].

Sun, Yipeng; /SLAC

2012-08-20T23:59:59.000Z

138

Hard x-ray (>100 keV) imager to measure hot electron preheat for indirectly driven capsule implosions on the NIF  

SciTech Connect (OSTI)

We have fielded a hard x-ray (>100 keV) imager with high aspect ratio pinholes to measure the spatially resolved bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. These electrons are generated in laser plasma interactions and are a source of preheat to the deuterium-tritium fuel. First measurements show that hot electron preheat does not limit obtaining the fuel areal densities required for ignition and burn.

Doeppner, T.; Dewald, E. L.; Divol, L.; Thomas, C. A.; Burns, S.; Celliers, P. M.; Izumi, N.; LaCaille, G.; McNaney, J. M.; Prasad, R. R.; Robey, H. F.; Glenzer, S. H.; Landen, O. L. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Kline, J. L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-10-15T23:59:59.000Z

139

Transition of an X-ray binary to the hard ultraluminous state in the blue compact dwarf galaxy VII Zw 403  

E-Print Network [OSTI]

We examine the X-ray spectra of VII Zw 403, a nearby low-metallicity blue compact dwarf (BCD) galaxy. The galaxy has been observed to contain an X-ray source, likely a high mass X-ray binary (HMXB), with a luminosity of 1.3-23x10^38 erg s^-1 in the 0.3-8 keV energy range. A new Suzaku observation shows a transition to a luminosity of 1.7x10^40 erg s^-1 [0.3-8 keV], higher by a factor of 7-130. The spectra from the high flux state are hard, best described by a disk plus Comptonization model, and exhibit curvature at energies above 5 keV. This is consistent with many high-quality ultraluminous X-ray source spectra which have been interpreted as stellar mass black holes (StMBH) accreting at super-Eddington rates. However, this lies in contrast to another HMXB in a low-metallicity BCD, I Zw 18, that exhibits a soft spectrum at high flux, similar to Galactic black hole binaries and has been interpreted as a possible intermediate mass black hole. Determining the spectral properties of HMXBs in BCDs has important im...

Brorby, Matthew; Feng, Hua

2015-01-01T23:59:59.000Z

140

Spectroscopic investigations of hard x-ray emission from 120 ps laser-produced plasmas at intensities near 10{sup 17} W cm{sup {minus}2}  

SciTech Connect (OSTI)

Spectroscopic investigations of the x-ray emission of plasmas heated by 120 ps, frequency doubled pulses from the JANUS Nd: glass laser are presented. High Z K-shell spectra emitted from slab targets heated to near 10{sup 17} W cm{sup {minus}2} intensity are investigated. High resolution ({gamma}/{Delta}{gamma}>5000) x-ray spectra of multicharged ions of H-like Ti, Co, Ni, Cu, and also H-like Sc in the spectral range 1.5--3.0 {angstrom} are obtained in single laser shots using a spherically bent Mica crystal spectrograph with a 186 mm radius of curvature. The spectra- have one dimensional spatial resolution of about 25{mu}m and indicate that the size of the emission zone of the resonance, transitions is <25{mu}m. Simultaneous x-ray images of the plasma from a charge-coupled device pinhole camera confirmed that the plasma x-ray emission is from a similar sized source. Survey spectra {gamma}/{Delta}{gamma}=500--1000) taken with a flat LiF (200) crystal spectrometer with a charge-coupled device detector complement the high resolution data. Two dimensional LASNEX modeling of the laser target conditions indicate that the high K-shell charge states are produced in the hot dense region of the plasma with electron temperature >2 keV and density{approximately}10{sup 22} cm{sup {minus}3}. These experiments demonstrate that with modest laser energy, plasmas heated by high-intensity 120 ps lasers provide a very bright source of hard {approximately}8 keV x-ray emission.

Dunn, J.; Young, B.K.F.; Osterheld, A.L.; Foord, M.E.; Walling, R.S.; Stewart, R.E. [Lawrence Livermore National Lab., CA (United States); Faenov, A.Y. [VINIFTRI, Mendeleevo, Moscow Region (Russian Federation)

1995-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
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141

HARD X-RAY EMISSION IN THE STAR-FORMING REGION ON 2: DISCOVERY WITH XMM-NEWTON  

SciTech Connect (OSTI)

We obtained X-ray XMM-Newton observations of the open cluster Berkeley 87 and the massive star-forming region (SFR) ON 2. In addition, archival infrared Spitzer Space Telescope observations were used to study the morphology of ON 2, to uncover young stellar objects, and to investigate their relationship with the X-ray sources. It is likely that the SFR ON 2 and Berkeley 87 are at the same distance, 1.23 kpc, and hence are associated. The XMM-Newton observations detected X-rays from massive stars in Berkeley 87 as well as diffuse emission from the SFR ON 2. The two patches of diffuse X-ray emission are encompassed in the shell-like H II region GAL 75.84+0.40 in the northern part of ON 2 and in the ON 2S region in the southern part of ON 2. The diffuse emission from GAL 75.84+0.40 suffers an absorption column equivalent to A{sub V} {approx} 28 mag. Its spectrum can be fitted either with a thermal plasma model at T {approx}> 30 MK or by an absorbed power-law model with gamma {approx} -2.6. The X-ray luminosity of GAL 75.84+0.40 is L{sub X} {approx} 6 x 10{sup 31} erg s{sup -1}. The diffuse emission from ON 2S is adjacent to the ultra-compact H II (UCH II) region Cygnus 2N, but does not coincide with it or with any other known UCH II region. It has a luminosity of L{sub X} {approx} 4 x 10{sup 31} erg s{sup -1}. The spectrum can be fitted with an absorbed power-law model with gamma {approx} -1.4. We adopt the view of Turner and Forbes that the SFR ON 2 is physically associated with the massive star cluster Berkeley 87 hosting the WO-type star WR 142. We discuss different explanations for the apparently diffuse X-ray emission in these SFRs. These include synchrotron radiation, invoked by the co-existence of strongly shocked stellar winds and turbulent magnetic fields in the star-forming complex, cluster wind emission, or an unresolved population of discrete sources.

Oskinova, L. M.; Hamann, W.-R.; Feldmeier, A. [Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam (Germany); Gruendl, R. A.; Chu, Y.-H. [Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States); Ignace, R., E-mail: lida@astro.physik.uni-potsdam.d [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614 (United States)

2010-04-01T23:59:59.000Z

142

Hard X-Ray Emission in the Star-Forming Region ON 2: Discovery with XMM-Newton  

Science Journals Connector (OSTI)

We obtained X-ray XMM-Newton observations of the open cluster Berkeley 87 and the massive star-forming region (SFR) ON 2. In addition, archival infrared Spitzer Space Telescope observations were used to study the morphology of ON 2, to uncover young stellar objects, and to investigate their relationship with the X-ray sources. It is likely that the SFR ON 2 and Berkeley 87 are at the same distance, 1.23 kpc, and hence are associated. The XMM-Newton observations detected X-rays from massive stars in Berkeley 87 as well as diffuse emission from the SFR ON 2. The two patches of diffuse X-ray emission are encompassed in the shell-like H II region GAL 75.84+0.40 in the northern part of ON 2 and in the ON 2S region in the southern part of ON 2. The diffuse emission from GAL 75.84+0.40 suffers an absorption column equivalent to A V ? 28 mag. Its spectrum can be fitted either with a thermal plasma model at T 30 MK  or by an absorbed power-law model with ? ? –2.6. The X-ray luminosity of GAL 75.84+0.40 is L X ? 6 ? 1031 erg s–1. The diffuse emission from ON 2S is adjacent to the ultra-compact H II (UCH II) region Cygnus 2N, but does not coincide with it or with any other known UCH II region. It has a luminosity of L X ? 4 ? 1031 erg s–1. The spectrum can be fitted with an absorbed power-law model with ? ? –1.4. We adopt the view of Turner & Forbes that the SFR ON 2 is physically associated with the massive star cluster Berkeley 87 hosting the WO-type star WR 142. We discuss different explanations for the apparently diffuse X-ray emission in these SFRs. These include synchrotron radiation, invoked by the co-existence of strongly shocked stellar winds and turbulent magnetic fields in the star-forming complex, cluster wind emission, or an unresolved population of discrete sources.

L. M. Oskinova; R. A. Gruendl; R. Ignace; Y.-H. Chu; W.-R. Hamann; A. Feldmeier

2010-01-01T23:59:59.000Z

143

VLBI OBSERVATION OF MICROQUASAR CYG X-3 DURING AN X-RAY STATE TRANSITION FROM SOFT TO HARD IN THE 2007 MAY-JUNE FLARE  

SciTech Connect (OSTI)

We present a radio observation of microquasar Cyg X-3 during an X-ray state transition from ultrasoft to hard state in the 2007 May-June flare using the VLBI Exploration of Radio Astrometry at 22 GHz. During the transition, a short-lived mini-flare of {approx}< 3 hr was detected prior to the major flare. In such a transition, a jet ejection is believed to occur, but there have been no direct observations to support it. An analysis of Gaussian fits to the observed visibility amplitudes shows a time variation of the source axis, or a structural change, during the mini-flare. Our model fits, together with other multiwavelength observations in the radio, soft, and hard X-rays, and the shock-in-jet models for other flaring activities at GHz wavebands, suggest a high possibility of synchrotron flares during the mini-flare, indicative of a predominant contribution from jet activity. Therefore, the mini-flare with an associated structural change is indicative of a jet ejection event in the state transition from ultrasoft to hard state.

Kim, Jeong-Sook; Kim, Sang Joon [School of Space Science, Kyunghee University, Seocheon-dong, Giheung-si, Gyeonggi-do 446-701 (Korea, Republic of); Kim, Soon-Wook [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Kurayama, Tomoharu [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890-0065 (Japan); Honma, Mareki [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Sasao, Tetsuo, E-mail: evony@kasi.re.kr, E-mail: skim@kasi.re.kr [Yaeyama Star Club, Ookawa, Ishigaki, Okinawa 904-0022 (Japan)

2013-07-20T23:59:59.000Z

144

A novel hohlraum with ultrathin depleted-uranium-nitride coating layer for low hard x-ray emission and high radiation temperature  

E-Print Network [OSTI]

An ultra-thin layer of uranium nitrides (UN) has been coated on the inner surface of the depleted uranium hohlraum (DUH), which has been proved by our experiment can prevent the oxidization of Uranium (U) effectively. Comparative experiments between the novel depleted uranium hohlraum and pure golden (Au) hohlraum are implemented on Shenguang III prototype laser facility. Under the laser intensity of 6*10^14 W/cm2, we observe that, the hard x-ray (> 1.8 keV) fraction of this uranium hohlraum decreases by 61% and the peak intensity of total x-ray flux (0.1 keV ~ 5 keV) increases by 5%. Two dimensional radiation hydrodynamic code LARED are exploited to interpret the above observations. Our result for the first time indicates the advantage of the UN-coated DUH in generating the uniform x-ray field with a quasi Planckian spectrum and thus has important implications in optimizing the ignition hohlraum design.

Guo, Liang; Xing, Peifeng; Li, Sanwei; Yi, Taimin; Kuang, Longyu; Li, Zhichao; Li, Renguo; Wu, Zheqing; Jing, Longfei; Zhang, Wenhai; Zhan, Xiayu; Yang, Dong; Jiang, Bobi; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen; Li, Yongsheng; Liu, Jie; Huo, Wenyi; Lan, Ke

2014-01-01T23:59:59.000Z

145

Gamma-Ray and Hard X-Ray Emission from Pulsar-Aided Supernovae as a Probe of Particle Acceleration in Embryonic Pulsar Wind Nebulae  

E-Print Network [OSTI]

It has been suggested that some classes of luminous supernovae (SNe) and gamma-ray bursts (GRBs) are driven by newborn magnetars. Fast-rotating proto-neutron stars have also been of interest as potential sources of gravitational waves (GWs). We show that for a range of rotation periods and magnetic fields, hard X rays and GeV gamma rays provide us with a promising probe of pulsar-aided SNe. It is observationally known that young pulsar wind nebulae (PWNe) in the Milky Way are very efficient lepton accelerators. We argue that, if embryonic PWNe satisfy similar conditions at early stages of SNe (in ~1-10 months after the explosion), external inverse-Compton emission via upscatterings of SN photons is naturally expected in the GeV range as well as broadband synchrotron emission. To fully take into account the Klein-Nishina effect and two-photon annihilation process that are important at early times, we perform detailed calculations including electromagnetic cascades. Our results suggest that hard X-ray telescope...

Murase, Kohta; Kiuchi, Kenta; Bartos, Imre

2014-01-01T23:59:59.000Z

146

Expectations for the Hard X-ray Continuum and Gamma-ray Line Fluxes from the Type Ia supernova SN 2014J in M82  

E-Print Network [OSTI]

The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the $^{56}$Ni yield and spatial distribution, its kinetic energy and expansion speed, and the mechanism of explosion. Such signatures and their time behavior "X-ray" the bulk debris field in direct fashion, and do not depend upon the oftimes problematic and elaborate UV, optical, and near-infrared spectroscopy and radiative transfer that have informed the study of these events for decades. However, to date no hard photons have ever been detected from a Type Ia supernova in explosion. With the advent of the supernova SN 2014J in M82, at a distance of $\\sim$3.5 Mpc, this situation may soon change. Both NuSTAR and INTEGRAL have the potential to detect SN 2014J, and, if spectra and light curves can be measured, would usefully constrain the various explosion models published during the last $\\sim$thirty years. In support of these observational ...

The, Lih-Sin

2014-01-01T23:59:59.000Z

147

Hard x-ray photoelectron spectroscopy study on band alignment at poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/ZnO interface  

SciTech Connect (OSTI)

We used hard x-ray photoelectron spectroscopy to investigate the interfacial electronic states of a poly(styrenesulfonate) doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) contact on a ZnO single crystal. An understanding of the interfacial band structure is useful for putting the organic contact to practical use. We observed upward band bending of the ZnO layer a few nanometers from the interface. The detected ZnO bulk region exhibited a flat band structure, meaning that the PEDOT:PSS does not greatly deplete the ZnO layer. The band bending caused the charge injection barrier formation with the result that the contact exhibited the Schottky property.

Nagata, T.; Hayakawa, R.; Chikyow, T. [International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Oh, S.; Wakayama, Y. [International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Department of Chemistry and Biochemistry, Faculty of Engineering, Kyushu University, 1-1 Namiki, Tsukuba 305-0044 (Japan); Yamashita, Y. [International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); NIMS Beamline Station at SPring-8, National Institute for Materials Science, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yoshikawa, H.; Kobayashi, K. [NIMS Beamline Station at SPring-8, National Institute for Materials Science, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2012-10-22T23:59:59.000Z

148

Investigation of the near-surface structures of polar InN films by chemical-state-discriminated hard X-ray photoelectron diffraction  

SciTech Connect (OSTI)

Near-surface structures of polar InN films were investigated by laboratory-based hard X-ray photoelectron diffraction (HXPD) with chemical-state-discrimination. HXPD patterns from In 3d{sub 5/2} and N 1s core levels of the In-polar and N-polar InN films were different from each other and compared with the simulation results using a multiple-scattering cluster model. It was found that the near-surface structure of the In-polar InN film was close to the ideal wurtzite structure. On the other hand, on the N-polar InN film, defects-rich surface was formed. In addition, the existence of the In-polar domains was observed in the HXPD patterns.

Yang, A. L.; Yamashita, Y.; Kobata, M.; Yoshikawa, H.; Sakata, O.; Kobayashi, K. [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Sayo-cho, Hyogo 679-5148 (Japan)] [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Sayo-cho, Hyogo 679-5148 (Japan); Matsushita, T. [Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5198 (Japan); Pis, I. [Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 18000 Prague 8 (Czech Republic)] [Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Imura, M. [Wide Bandgap Materials Group, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan)] [Wide Bandgap Materials Group, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Yamaguchi, T. [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan)] [Department of Photonics, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan); Nanishi, Y. [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea and Research Organization of Science and Engineering, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga 525-8577 (Japan)] [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea and Research Organization of Science and Engineering, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga 525-8577 (Japan)

2013-01-21T23:59:59.000Z

149

Impact of Mg concentration on energy-band-depth profile of Mg-doped InN epilayers analyzed by hard X-ray photoelectron spectroscopy  

SciTech Connect (OSTI)

The electronic structures of Mg-doped InN (Mg-InN) epilayers with the Mg concentration, [Mg], ranging from 1 × 10{sup 19} to 5 × 10{sup 19} cm{sup ?3} were systematically investigated by soft and hard X-ray photoelectron spectroscopies. The angle-resolved results on the core-level and valence band photoelectron spectra as a function of [Mg] revealed that the energy band of Mg-InN showed downward bending due to the n{sup +} surface electron accumulation and p type layers formed in the bulk. With an increase in [Mg], the energy-band changed from monotonic to two-step n{sup +}p homojunction structures. The oxygen concentration rapidly increased at the middle-bulk region (?4.5 to ?7.5 nm) from the surface, which was one of the reasons of the transformation of two-step energy band.

Imura, M.; Tsuda, S.; Nagata, T.; Takeda, H.; Liao, M. Y.; Koide, Y. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)] [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Yang, A. L.; Yamashita, Y.; Yoshikawa, H.; Kobayashi, K. [NIMS/SPring-8, NIMS, 1-1-1 Koto, Sayo-cho, Sayo, Hyogo 679-5148 (Japan)] [NIMS/SPring-8, NIMS, 1-1-1 Koto, Sayo-cho, Sayo, Hyogo 679-5148 (Japan); Yamaguchi, T. [Faculty of Engineering, Kogakuin University, 2665-1 Nakano-machi, Hachiouji, Tokyo 192-0015 (Japan) [Faculty of Engineering, Kogakuin University, 2665-1 Nakano-machi, Hachiouji, Tokyo 192-0015 (Japan); Faculty of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577 (Japan); Kaneko, M.; Uematsu, N.; Wang, K.; Araki, T. [Faculty of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577 (Japan)] [Faculty of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577 (Japan); Nanishi, Y. [Faculty of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577 (Japan) [Faculty of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577 (Japan); Faculty of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2013-10-14T23:59:59.000Z

150

Quantitative studies on inner interfaces in conical metal joints using hard x-ray inline phase contrast radiography  

SciTech Connect (OSTI)

Quantitative investigation of micrometer and submicrometer gaps between joining metal surfaces is applied to conical plug-socket connections in dental titanium implants. Microgaps of widths well beyond the resolving power of industrial x-ray systems are imaged by synchrotron phase contrast radiography. Furthermore, by using an analytical model for the relatively simple sample geometry and applying it to numerical forward simulations of the optical Fresnel propagation, we show that quantitative measurements of the microgap width down to 0.1 {mu}m are possible. Image data recorded at the BAMline (BESSY-II light source, Germany) are presented, with the resolving power of the imaging system being 4 {mu}m in absorption mode and {approx}14 {mu}m in phase contrast mode (z{sub 2}=0.74 m). Thus, phase contrast radiography, combined with numerical forward simulations, is capable of measuring the widths of gaps that are two orders of magnitude thinner than the conventional detection limit.

Zabler, S. [Institute for Materials Science, Technical University of Berlin, EB 13, Strasse des 17, Juni 135, D-10623 Berlin (Germany); Rack, T.; Nelson, K. [Clinic for Oral and Maxifacial Surgery, Charite University Medicine, Augustenburger Platz 1, D-13353 Berlin (Germany); Rack, A. [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, F-38043 Grenoble (France)

2010-10-15T23:59:59.000Z

151

Magnetism studies using resonant, coherent, x-ray scattering...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Magnetism studies using resonant, coherent, x-ray scattering Monday, September 10, 2012 - 10:00am SLAC, Bldg. 137, Room 226 Keoki Seu Seminar: With the advent of free electron...

152

PLASMA HEATING IN A POST ERUPTION CURRENT SHEET: A CASE STUDY BASED ON ULTRAVIOLET, SOFT, AND HARD X-RAY DATA  

SciTech Connect (OSTI)

Off-limb observations of the solar corona after coronal mass ejections (CMEs) often show strong, compact, and persistent UV sources behind the eruption. They are primarily observed by the SOHO/UVCS instrument in the 'hot' [Fe XVIII] ?974 line and are usually interpreted as a signature of plasma heating due to magnetic reconnection in the post-CME current sheet (CS). Nevertheless, the physical process itself and the altitude of the main energy release are currently not fully understood. In this work, we study the evolution of plasma heating after the CME of 2004 July 28 by comparing UV spectra acquired by UVCS with soft and hard X-ray (SXR, HXR) images of the post-flare loops taken by GOES/SXI and RHESSI. The X-ray data show a long-lasting extended source that is rising upward, toward the high-temperature source detected by UVCS. UVCS data show the presence of significant non-thermal broadening in the CS (a signature of turbulent motions) and a strong density gradient across the CS region. The thermal energy released in the HXR source is on the order of ?10{sup 32} erg, a factor ?2-5 larger than the energy required to explain the high-temperature plasma sampled by UVCS. Nevertheless, the very different time evolutions of SXR and HXR sources compared with the UV emission suggest that reconnection occurring above the post-eruption arcades is not directly responsible for the high-temperature plasma sampled higher up by UVCS. We conclude that an additional plasma heating mechanism (such as turbulent reconnection) in the CS is likely required.

Susino, R.; Bemporad, A. [INAF - Osservatorio Astrofisico di Torino, via Osservatorio 20, I-10025 Pino Torinese (Italy); Krucker, Säm, E-mail: sur@oact.inaf.it, E-mail: krucker@ssl.berkeley.edu [University of Applied Sciences and Arts Northwestern Switzerland, CH-5210 Windisch (Switzerland)

2013-11-10T23:59:59.000Z

153

X-ray transmissive debris shield  

DOE Patents [OSTI]

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, R.B.

1996-05-21T23:59:59.000Z

154

X-ray transmissive debris shield  

DOE Patents [OSTI]

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, Rick B. (Albuquerque, NM)

1996-01-01T23:59:59.000Z

155

Polarisation measurements with a CdTe pixel array detector for Laue hard X-ray focusing telescopes  

E-Print Network [OSTI]

Polarimetry is an area of high energy astrophysics which is still relatively unexplored, even though it is recognized that this type of measurement could drastically increase our knowledge of the physics and geometry of high energy sources. For this reason, in the context of the design of a Gamma-Ray Imager based on new hard-X and soft gamma ray focusing optics for the next ESA Cosmic Vision call for proposals (Cosmic Vision 2015-2025), it is important that this capability should be implemented in the principal on-board instrumentation. For the particular case of wide band-pass Laue optics we propose a focal plane based on a thick pixelated CdTe detector operating with high efficiency between 60-600 keV. The high segmentation of this type of detector (1-2 mm pixel size) and the good energy resolution (a few keV FWHM at 500 keV) will allow high sensitivity polarisation measurements (a few % for a 10 mCrab source in 106s) to be performed. We have evaluated the modulation Q factors and minimum detectable polaris...

Caroli, E; Pisa, A; Stephen, J B; Frontera, F; Castanheira, M T D; Sordo, S; Caroli, Ezio; Silva, Rui M. Curado da; Pisa, Alessandro; Stephen, John B.; Frontera, Filippo; Castanheira, Matilde T. D.; Sordo, Stefano del

2006-01-01T23:59:59.000Z

156

Polarisation measurements with a CdTe pixel array detector for Laue hard X-ray focusing telescopes  

E-Print Network [OSTI]

Polarimetry is an area of high energy astrophysics which is still relatively unexplored, even though it is recognized that this type of measurement could drastically increase our knowledge of the physics and geometry of high energy sources. For this reason, in the context of the design of a Gamma-Ray Imager based on new hard-X and soft gamma ray focusing optics for the next ESA Cosmic Vision call for proposals (Cosmic Vision 2015-2025), it is important that this capability should be implemented in the principal on-board instrumentation. For the particular case of wide band-pass Laue optics we propose a focal plane based on a thick pixelated CdTe detector operating with high efficiency between 60-600 keV. The high segmentation of this type of detector (1-2 mm pixel size) and the good energy resolution (a few keV FWHM at 500 keV) will allow high sensitivity polarisation measurements (a few % for a 10 mCrab source in 106s) to be performed. We have evaluated the modulation Q factors and minimum detectable polarisation through the use of Monte Carlo simulations (based on the GEANT 4 toolkit) for on and off-axis sources with power law emission spectra using the point spread function of a Laue lens in a feasible configuration.

Ezio Caroli; Rui M. Curado da Silva; Alessandro Pisa; John B. Stephen; Filippo Frontera; Matilde T. D. Castanheira; Stefano del Sordo

2006-05-25T23:59:59.000Z

157

X-ray Observations of Mrk 231  

E-Print Network [OSTI]

This paper presents new X-ray observations of Mrk 231, an active galaxy of particular interest due to its large infrared luminosity and the presence of several blueshifted broad absorption line (BAL) systems, a phenomenon observed in a small fraction of QSOs. A ROSAT HRI image of Mrk 231 is presented, this shows an extended region of soft X-ray emission, covering several tens of kpc, consistent with the extent of the host galaxy. An ASCA observation of Mrk 231 is also presented. Hard X-rays are detected but the data show no significant variability in X-ray flux. The hard X-ray continuum is heavily attenuated and X-ray column estimates range from ~ 2 x 10^{22} - 10^{23} cm^{-2} depending on whether the material is assumed to be neutral or ionized, and on the model assumed for the extended X-ray component. These ASCA data provide only the second hard X-ray spectrum of a BAL AGN presented to date. The broad-band spectral-energy-distribution of the source is discussed. While Mrk 231 is X-ray weak compared to Seyfert 1 galaxies, it has an optical-to-X-ray spectrum typical of a QSO.

T. J. Turner

1998-08-10T23:59:59.000Z

158

Direct observation of bias-dependence potential distribution in metal/HfO{sub 2} gate stack structures by hard x-ray photoelectron spectroscopy under device operation  

SciTech Connect (OSTI)

Although gate stack structures with high-k materials have been extensively investigated, there are some issues to be solved for the formation of high quality gate stack structures. In the present study, we employed hard x-ray photoelectron spectroscopy in operating devices. This method allows us to investigate bias dependent electronic states, while keeping device structures intact. Using this method, we have investigated electronic states and potential distribution in gate metal/HfO{sub 2} gate stack structures under device operation. Analysis of the core levels shifts as a function of the bias voltage indicated that a potential drop occurred at the Pt/HfO{sub 2} interface for a Pt/HfO{sub 2} gate structure, while a potential gradient was not observed at the Ru/HfO{sub 2} interface for a Ru/HfO{sub 2} gate structure. Angle resolved photoelectron spectroscopy revealed that a thicker SiO{sub 2} layer was formed at the Pt/HfO{sub 2} interface, indicating that the origin of potential drop at Pt/HfO{sub 2} interface is formation of the thick SiO{sub 2} layer at the interface. The formation of the thick SiO{sub 2} layer at the metal/high-k interface might concern the Fermi level pinning, which is observed in metal/high-k gate stack structures.

Yamashita, Y. [National Institute for Materials Science, Advanced Electric Materials Center, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); National Institute for Materials Science, NIMS Beamline Station at SPring-8, 1-1-1 Kôto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yoshikawa, H.; Kobayashi, K. [National Institute for Materials Science, NIMS Beamline Station at SPring-8, 1-1-1 Kôto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Chikyo, T. [National Institute for Materials Science, Advanced Electric Materials Center, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2014-01-28T23:59:59.000Z

159

Massively parallel X-ray holography STEFANO MARCHESINI1,2  

E-Print Network [OSTI]

, and a bacterial cell with a soft-X-ray free-electron laser, where illumination by a single 15-fs pulse was successfully used in producing the holographic image. As X-ray lasers move to shorter wavelengths we expectMassively parallel X-ray holography STEFANO MARCHESINI1,2 *, SE´BASTIEN BOUTET3,4 , ANNE E

Petta, Jason

160

Generation of very high-frequency waves by up-conversion in a plasma-loaded free-electron laser  

Science Journals Connector (OSTI)

A free-electron laser loaded with a plasma is able to resonate at two different frequencies. The two waves are copropagating, one with positive slippage while the other has negative slippage. We deduce the nonlinear partial differential equations describing the interaction between the two waves in the slowly-varying-envelope approximation. By injecting a signal at the low frequency, a strong signal is produced at the harmonically related high frequency, with a lethargy time much smaller than that of the spontaneous vacuum emission. This effect could be applied in the generation of very short wavelength radiation, up to the range of hard x rays.

V. Petrillo and C. Maroli

2000-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Lensless X-Ray Imaging in Reflection  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Lensless X-Ray Imaging in Lensless X-Ray Imaging in Reflection Lensless X-Ray Imaging in Reflection Print Wednesday, 26 October 2011 00:00 The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

162

Progress toward the Wisconsin Free Electron Laser  

SciTech Connect (OSTI)

The University of Wisconsin-Madison/Synchrotron Radiation Center is advancing its design for a seeded VUV/soft X-ray Free Electron Laser facility called WiFEL. To support this vision of an ultimate light source, we are pursuing a program of strategic R&D addressing several crucial elements. This includes development of a high repetition rate, VHF superconducting RF electron gun, R&D on photocathode materials by ARPES studies, and evaluation of FEL facility architectures (e.g., recirculation, compressor scenarios, CSR dechirping, undulator technologies) with the specific goal of cost containment. Studies of high harmonic generation for laser seeding are also planned.

Bisognano, Joseph; Eisert, D; Fisher, M V; Green, M A; Jacobs, K; Kleman, K J; Kulpin, J; Rogers, G C; Lawler, J E; Yavuz, D

2011-03-01T23:59:59.000Z

163

SOFT X-RAY EMISSIONS FROM PLANETS, MOONS, AND COMETS A. Bhardwaj(1)  

E-Print Network [OSTI]

SOFT X-RAY EMISSIONS FROM PLANETS, MOONS, AND COMETS A. Bhardwaj(1) , G. R. Gladstone(2) , R. F to radiate in the soft x-ray energy ( the generation of soft x-rays from these objects, whereas in the hard x-ray energy range (>10 keV) x-rays mainly

Johnson, Robert E.

164

Injection of harmonics generated in gas in a free-electron laser providing intense and  

E-Print Network [OSTI]

-ultraviolet to X-ray region. Recently, injection of a single-pass FEL by the third laser harmonic of a TiLETTERS Injection of harmonics generated in gas in a free-electron laser providing intense-electron lasers promise to extend this down to femtosecond timescales. The process by which free-electron lasers

Loss, Daniel

165

ROXA J081009.9+384757.0: a $10^{47}$ erg/s blazar with hard X-ray synchrotron peak or a new type of radio loud AGN?  

E-Print Network [OSTI]

We report the discovery of ROXA J081009.9+384757.0 = SDSS J081009.9+384757.0, a z=3.95 blazar with a highly unusual Spectral Energy Distribution (SED). This object was first noticed as a probable high $f_x/f_r$, high-luminosity blazar within the error region of a $\\approx 10^{-12}$ erg/s cm$^2$ ROSAT source which, however, also included a much brighter late-type star. We describe the results of a recent Swift observation that establishes beyond doubt that the correct counterpart of the X-ray source is the flat spectrum radio quasar. With a luminosity well in excess of $10^{47}$ erg/s, ROXA J081009.9+384757.0 is therefore one of the most luminous blazars known. We consider various possibilities for the nature of the electromagnetic emission from this source. In particular, we show that the SED is consistent with that of a blazar with synchrotron power peaking in the hard X-ray band. If this is indeed the case, the combination of high-luminosity and synchrotron peak in the hard-X-ray band contradicts the claime...

Giommi, P; Padovani, P; Perri, M; Cavazzuti, E; Turriziani, S; Tosti, G; Colafrancesco, S; Tagliaferri, G; Chincarini, G; Burrows, D N; Chester, M M M; Gehrels, N

2007-01-01T23:59:59.000Z

166

Lensless X-Ray Imaging in Reflection  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Imaging in Reflection Print X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

167

Lensless X-Ray Imaging in Reflection  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Imaging in Reflection Print X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

168

Lensless X-Ray Imaging in Reflection  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Lensless X-Ray Imaging in Reflection Print Lensless X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

169

Lensless X-Ray Imaging in Reflection  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Lensless X-Ray Imaging in Reflection Print Lensless X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

170

ROXA J081009.9+384757.0: a $10^{47}$ erg/s blazar with hard X-ray synchrotron peak or a new type of radio loud AGN?  

E-Print Network [OSTI]

We report the discovery of ROXA J081009.9+384757.0 = SDSS J081009.9+384757.0, a z=3.95 blazar with a highly unusual Spectral Energy Distribution (SED). This object was first noticed as a probable high $f_x/f_r$, high-luminosity blazar within the error region of a $\\approx 10^{-12}$ erg/s cm$^2$ ROSAT source which, however, also included a much brighter late-type star. We describe the results of a recent Swift observation that establishes beyond doubt that the correct counterpart of the X-ray source is the flat spectrum radio quasar. With a luminosity well in excess of $10^{47}$ erg/s, ROXA J081009.9+384757.0 is therefore one of the most luminous blazars known. We consider various possibilities for the nature of the electromagnetic emission from this source. In particular, we show that the SED is consistent with that of a blazar with synchrotron power peaking in the hard X-ray band. If this is indeed the case, the combination of high-luminosity and synchrotron peak in the hard-X-ray band contradicts the claimed anti-correlation between luminosity and position of the synchrotron peak usually referred to as the "blazar sequence". An alternative possibility is that the X-rays are not due to synchrotron emission, in this case the very peculiar SED of ROXA J081009.9+384757.0 would make it the first example of a new class of radio loud AGN.

P. Giommi; E. Massaro; P. Padovani; M. Perri; E. Cavazzuti; S. Turriziani; G. Tosti; S. Colafrancesco; G. Tagliaferri; G. Chincarini; D. N. Burrows; M. McMath Chester; N. Gehrels

2007-03-19T23:59:59.000Z

171

Time-resolved protein nanocrystallography using an X-ray free...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Time-resolved protein nanocrystallography using an X-ray free-electron laser Authors: Aquila, A., Hunter, M. S., Doak, R. B., Kirian, R. A., Fromme, P., White, T. A., Andreasson,...

172

Chest x-Rays  

Broader source: Energy.gov [DOE]

The B-reading is a special reading of a standard chest x-ray film performed by a physician certified by the National Institute for Occupational Safety and Health (NIOSH). The reading looks for changes on the chest x-ray that may indicate exposure and disease caused by agents such as asbestos or silica.

173

X-ray beamsplitter  

DOE Patents [OSTI]

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

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

1987-08-07T23:59:59.000Z

174

X-ray beamsplitter  

DOE Patents [OSTI]

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

Ceglio, Natale M. (Livermore, CA); Stearns, Daniel S. (Mountain View, CA); Hawryluk, Andrew M. (Modesto, CA); Barbee, Jr., Troy W. (Palo Alto, CA)

1989-01-01T23:59:59.000Z

175

X-ray binaries  

E-Print Network [OSTI]

We review the nuclear astrophysics aspects of accreting neutron stars in X-ray binaries. We summarize open astrophysical questions in light of recent observations and their relation to the underlying nuclear physics. Recent progress in the understanding of the nuclear physics, especially of X-ray bursts, is also discussed.

H. Schatz; K. E. Rehm

2006-08-01T23:59:59.000Z

176

Incoherent x-ray scattering in single molecule imaging  

E-Print Network [OSTI]

Imaging of the structure of single proteins or other biomolecules with atomic resolution would be enormously beneficial to structural biology. X-ray free-electron lasers generate highly intense and ultrashort x-ray pulses, providing a route towards imaging of single molecules with atomic resolution. The information on molecular structure is encoded in the coherent x-ray scattering signal. In contrast to crystallography there are no Bragg reflections in single molecule imaging, which means the coherent scattering is not enhanced. Consequently, a background signal from incoherent scattering deteriorates the quality of the coherent scattering signal. This background signal cannot be easily eliminated because the spectrum of incoherently scattered photons cannot be resolved by usual scattering detectors. We present an ab initio study of incoherent x-ray scattering from individual carbon atoms, including the electronic radiation damage caused by a highly intense x-ray pulse. We find that the coherent scattering pa...

Slowik, Jan Malte; Dixit, Gopal; Jurek, Zoltan; Santra, Robin

2014-01-01T23:59:59.000Z

177

Free electron laser  

DOE Patents [OSTI]

A high gain, single-pass free electron laser formed of a high brilliance electron injector source, a linear accelerator which imparts high energy to the electron beam, and an undulator capable of extremely high magnetic fields, yet with a very short period. The electron injector source is the first stage (gap) of the linear accelerator or a radial line transformer driven by fast circular switch. The linear accelerator is formed of a plurality of accelerating gaps arranged in series. These gaps are energized in sequence by releasing a single pulse of energy which propagates simultaneously along a plurality of transmission lines, each of which feeds the gaps. The transmission lines are graduated in length so that pulse power is present at each gap as the accelerated electrons pass therethrough. The transmission lines for each gap are open circuited at their ends. The undualtor has a structure similar to the accelerator, except that the transmission lines for each gap are substantially short circuited at their ends, thus converting the electric field into magnetic field. A small amount of resistance is retained in order to generate a small electric field for replenishing the electron bunch with the energy lost as it traverses through the undulator structure.

Villa, Francesco (Alameda, CA)

1990-01-01T23:59:59.000Z

178

Evolution of Cygnus X-3 through its Radio and X-ray States  

SciTech Connect (OSTI)

Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

Szostek, A. [Laboratoire d'Astrophysique de Grenoble, CNRS, Universite Joseph Fourier, Grenoble (France); Astronomical Observatory, Jagiellonian University, Krakow (Poland); Zdziarski, A. A. [Centrum Astronomiczne im. M. Kopernika, Warszawa (Poland); McCollough, M. L. [Smithsonian Astrophysical Observatory, Cambridge (United States)

2009-05-11T23:59:59.000Z

179

The Constellation X-ray mission  

Science Journals Connector (OSTI)

The Constellation-X mission is a large collecting area X-ray facility, emphasizing observations at high spectral resolution (E/?E?300–3000) while covering a broad energy band (0.25–40 keV). By increasing the telescope aperture and utilizing efficient spectrometers the mission will achieve a factor of 100 increased sensitivity over current high-resolution X-ray spectroscopy missions. The use of focussing optics across the 10–40 keV band will provide a similar factor of 100 increased sensitivity in this band. Key technologies under development for the mission include lightweight high throughput X-ray optics, multilayer coatings to enhance the hard X-ray performance of X-ray optics, micro-calorimeter spectrometer arrays with 2 eV resolution, low-power and low-weight CCD arrays, lightweight gratings and hard X-ray detectors. When observations commence towards the end of the next decade, Constellation-X will address many pressing questions concerning the extremes of gravity and the evolution of the Universe.

N.E White; H Tananbaum

1999-01-01T23:59:59.000Z

180

X-ray laser  

DOE Patents [OSTI]

An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

Nilsen, Joseph (Livermore, CA)

1991-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

X-ray absorption spectroscopy  

E-Print Network [OSTI]

009-9473-8 REVIEW X-ray absorption spectroscopy Junko Yano Æand application of X-ray absorption spectroscopy, bothX-ray absorption near-edge structure (XANES) and extended X-

Yano, Junko; Yachandra, Vittal K.

2009-01-01T23:59:59.000Z

182

X-ray Absorption Spectroscopy  

E-Print Network [OSTI]

type: Review X-ray Absorption Spectroscopy Junko Yano andPhotosystem II; XAS, X-ray absorption spectroscopy; EXAFS,X-ray absorption fine structure; EPR, electron paramagnetic

Yano, Junko

2010-01-01T23:59:59.000Z

183

X-Ray Generators  

Science Journals Connector (OSTI)

There are many types of X-ray generators sold commercially. The following are some of ... that should be considered when selecting a particular generator for a particular purpose. All the companies listed below s...

Reuben Rudman

1972-01-01T23:59:59.000Z

184

Circular free-electron laser  

DOE Patents [OSTI]

A high efficiency, free electron laser utilizing a circular relativistic electron beam accelerator and a circular whispering mode optical waveguide for guiding optical energy in a circular path in the circular relativistic electron beam accelerator such that the circular relativistic electron beam and the optical energy are spatially contiguous in a resonant condition for free electron laser operation. Both a betatron and synchrotron are disclosed for use in the present invention. A free electron laser wiggler is disposed around the circular relativistic electron beam accelerator for generating a periodic magnetic field to transform energy from the circular relativistic electron beam to optical energy.

Brau, Charles A. (Los Alamos, NM); Kurnit, Norman A. (Santa Fe, NM); Cooper, Richard K. (Los Alamos, NM)

1984-01-01T23:59:59.000Z

185

Argonne CNM: X-Ray Microscopy Capabilities  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Microscopy Facilities X-Ray Microscopy Facilities The Hard X-Ray Nanoprobe (HXN) facility provides scanning fluorescence, scanning diffraction, and full-field transmission and tomographic imaging capabilities with a spatial resolution of 30 nm over a spectral range of 6-12 keV. Modes of Operation Full-Field Transmission Imaging and Nanotomography X-ray transmission imaging uses both the absorption and phase shift of the X-ray beam by the sample as contrast mechanisms. Absorption contrast is used to map the sample density. Elemental constituents can be located by using differential edge contrast in this mode. Phase contrast can be highly sensitive to edges and interfaces even when the X-ray absorption is weak. These contrast mechanisms are exploited to image samples rapidly in full-field transmission mode under various environmental conditions, or combined with nanotomography methods to study the three-dimensional structure of complex and amorphous nanomaterials with the HXN.

186

Rf Feedback free electron laser  

DOE Patents [OSTI]

A free electron laser system and electron beam system for a free electron laser which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

Brau, Charles A. (Los Alamos, NM); Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

187

E-Print Network 3.0 - adc x-ray binary Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

-Planck code and its applications . . . 63 3.6.7 Observation of X-ray binaries with Simbol... for the hard X-ray emission of accreting black holes sources (both in Seyfert...

188

X-ray beam finder  

DOE Patents [OSTI]

An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

Gilbert, H.W.

1983-06-16T23:59:59.000Z

189

X-ray Spectrometry  

Science Journals Connector (OSTI)

These provide excellent energy resolution for a wide range of X-ray energies, from the optical range up to several kiloelectronvolts. ... The Astro-E2 launched in 2005 was the first mission that contained a low-temperature microcalorimeter-based observatory, and three more low-temperature detector-based observatories are being developed (NeXT, Constellation-X, ZEUS). ...

Imre Szalóki; János Osán; René E. Van Grieken

2006-05-10T23:59:59.000Z

190

Femtosecond Time-Delay X-ray Holography  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Time-Delay X-ray Holography Time-Delay X-ray Holography X-ray free-electron lasers (XFELs) will produce photon pulses with a unique and desirable combination of properties. Their short X-ray wavelengths allow penetration into materials and the ability to probe structure at and below the nanometer scale. Their ultra-short duration gives information about this structure at the fundamental time-scales of atoms and molecules. The extreme intensity of the pulses will allow this information to be acquired in a single shot, so that these studies can be carried out on non-repeatable processes or on weakly-scattering objects that will be modified by the pulse. A fourth property of XFEL pulses is their high transverse coherence, which brings the promise of decades of innovation in visible optics to the X-ray regime, such as holography, interferometry, and laser-based imaging. Making an effective use of XFEL pulses, however, will benefit from innovations that are new to both X-ray science and coherent optics. One such innovation is the new method of time-delay X-ray holography [i], recently demonstrated at the FLASH FEL at DESY in Hamburg, to measure the evolution of objects irradiated by intense pulses.

191

X-RAY POINT-SOURCE POPULATIONS CONSTITUTING THE GALACTIC RIDGE X-RAY EMISSION  

SciTech Connect (OSTI)

Apparently diffuse X-ray emission has been known to exist along the central quarter of the Galactic Plane since the beginning of X-ray astronomy; this is referred to as the Galactic Ridge X-ray emission (GRXE). Recent deep X-ray observations have shown that numerous X-ray point sources account for a large fraction of the GRXE in the hard band (2-8 keV). However, the nature of these sources is poorly understood. Using the deepest X-ray observations made in the Chandra bulge field, we present the result of a coherent photometric and spectroscopic analysis of individual X-ray point sources for the purpose of constraining their nature and deriving their fractional contributions to the hard-band continuum and Fe K line emission of the GRXE. Based on the X-ray color-color diagram, we divided the point sources into three groups: A (hard), B (soft and broad spectrum), and C (soft and peaked spectrum). The group A sources are further decomposed spectrally into thermal and non-thermal sources with different fractions in different flux ranges. From their X-ray properties, we speculate that the group A non-thermal sources are mostly active galactic nuclei and the thermal sources are mostly white dwarf (WD) binaries such as magnetic and non-magnetic cataclysmic variables (CVs), pre-CVs, and symbiotic stars, whereas the group B and C sources are X-ray active stars in flares and quiescence, respectively. In the log N-log S curve of the 2-8 keV band, the group A non-thermal sources are dominant above Almost-Equal-To 10{sup -14} erg cm{sup -2} s{sup -1}, which is gradually taken over by Galactic sources in the fainter flux ranges. The Fe K{alpha} emission is mostly from the group A thermal (WD binaries) and the group B (X-ray active stars) sources.

Morihana, Kumiko [Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)] [Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tsujimoto, Masahiro; Ebisawa, Ken [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)] [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Yoshida, Tessei, E-mail: morihana@crab.riken.jp [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)

2013-03-20T23:59:59.000Z

192

Inverse free electron laser accelerator for advanced light sources  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

We discuss the inverse free electron laser (IFEL) scheme as a compact high gradient accelerator solution for driving advanced light sources such as a soft x-ray free electron laser amplifier or an inverse Compton scattering based gamma-ray source. In particular, we present a series of new developments aimed at improving the design of future IFEL accelerators. These include a new procedure to optimize the choice of the undulator tapering, a new concept for prebunching which greatly improves the fraction of trapped particles and the final energy spread, and a self-consistent study of beam loading effects which leads to an energy-efficient high laser-to-beam power conversion.

Duris, J. P.; Musumeci, P.; Li, R. K.

2012-06-01T23:59:59.000Z

193

Nonthermal hard X-ray excess in the Coma cluster: resolving the discrepancy between the results of different PDS data analyses  

E-Print Network [OSTI]

The detection of a nonthermal excess in the Coma cluster spectrum by two BeppoSAX observations analyzed with the XAS package (Fusco-Femiano et al.) has been disavowed by an analysis (Rossetti & Molendi) performed with a different software package (SAXDAS) for the extraction of the spectrum. To resolve this discrepancy we reanalyze the PDS data considering the same software used by Rossetti & Molendi. A correct selection of the data and the exclusion of contaminating sources in the background determination show that also the SAXDAS analysis reports a nonthermal excess with respect to the thermal emission at about the same confidence level of that obtained with the XAS package (~4.8sigma). Besides, we report the lack of the systematic errors investigated by Rossetti & Molendi and Nevalainen et al. taking into account the whole sample of the PDS observations off the Galactic plane, as already shown in our data analysis of Abell 2256 (Fusco-Femiano, Landi & Orlandini). All this eliminates any ambiguity and confirms the presence of a hard tail in the spectrum of the Coma cluster.

Roberto Fusco-Femiano; Raffaella Landi; Mauro Orlandini

2006-11-10T23:59:59.000Z

194

Tunable X-ray source  

DOE Patents [OSTI]

A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

Boyce, James R. (Williamsburg, VA)

2011-02-08T23:59:59.000Z

195

In-operando hard X-ray photoelectron spectroscopy study on the impact of current compliance and switching cycles on oxygen and carbon defects in resistive switching Ti/HfO{sub 2}/TiN cells  

SciTech Connect (OSTI)

In this study, direct experimental materials science evidence of the important theoretical prediction for resistive random access memory (RRAM) technologies that a critical amount of oxygen vacancies is needed to establish stable resistive switching in metal-oxide-metal samples is presented. In detail, a novel in-operando hard X-ray photoelectron spectroscopy technique is applied to non-destructively investigates the influence of the current compliance and direct current voltage sweep cycles on the Ti/HfO{sub 2} interface chemistry and physics of resistive switching Ti/HfO{sub 2}/TiN cells. These studies indeed confirm that current compliance is a critical parameter to control the amount of oxygen vacancies in the conducting filaments in the oxide layer during the RRAM cell operation to achieve stable switching. Furthermore, clear carbon segregation towards the Ti/HfO{sub 2} interface under electrical stress is visible. Since carbon impurities impact the oxygen vacancy defect population under resistive switching, this dynamic carbon segregation to the Ti/HfO{sub 2} interface is suspected to negatively influence RRAM device endurance. Therefore, these results indicate that the RRAM materials engineering needs to include all impurities in the dielectric layer in order to achieve reliable device performance.

Sowinska, Malgorzata, E-mail: sowinska@ihp-microelectronics.com; Bertaud, Thomas; Walczyk, Damian; Calka, Pauline; Walczyk, Christian [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Thiess, Sebastian [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Alff, Lambert [Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Schroeder, Thomas [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

2014-05-28T23:59:59.000Z

196

Fresnel and refractive lenses for X-rays  

Science Journals Connector (OSTI)

We present a Gaussian beam analysis of X-ray refractive and Fresnel lenses. The X-ray refractive lens is featured by an intrinsic soft (Gaussian) aperture due to strong absorption of X-rays by materials. We defined a parameter N0, the critical Fresnel number (CFN), to describe this optical property. The values of N0 for all practical materials are below 1000 for photon energies exceeding 30 eV, still lower for high-Z materials. The maximum effective Fresnel number of a lens is determined by its material to be 2N0 and its maximum enhancement of X-ray intensity is limited to (2?N0)2, independent of its shape. We found that the refractive lens is likely to be useful for manipulating nearly diffraction limited beam in the hard X-ray region and its application is severely restricted by available fabrication capabilities today. X-ray Fresnel lenses, both in cylindrical and linear forms, are proposed as superior focusing elements for hard X-rays. Their high efficiency, up to 100% in optimal construction, will enable us to manipulate beams with multiple lenses and obtain higher performance optics. Their design and fabrication are discussed in reference to those of X-ray Fresnel zone plates and micro Fresnel lenses for optoelectronics.

B.X. Yang

1993-01-01T23:59:59.000Z

197

X-ray Spectrometry  

Science Journals Connector (OSTI)

The segmented STJ operated at total count rates of above 105 counts/s, and the best-achieved energy resolution of their single STJ was found to be 10 eV for X-ray energies below 1 keV. ... The Mo?Au TES, with an operating temperature of 230 mK, was developed for the Constellation-X mission and the energy resolution of the spectrometer is ?28 eV at 3.3 keV. ...

Imre Szalóki; Szabina B. Török; Jasna Injuk; René E. Van Grieken

2002-05-18T23:59:59.000Z

198

High-Gain Harmonic-Generation Free-Electron Laser  

Science Journals Connector (OSTI)

...originally built by STI Optronics for use in a visible FEL at Boeing. 35 Recent theoretical work on generating...originally built by STI Optronics for use in a visible FEL at Boeing. Recent theoretical work on generating hard x-rays by cascading...

L.-H. Yu; M. Babzien; I. Ben-Zvi; L. F. DiMauro; A. Doyuran; W. Graves; E. Johnson; S. Krinsky; R. Malone; I. Pogorelsky; J. Skaritka; G. Rakowsky; L. Solomon; X. J. Wang; M. Woodle; V. Yakimenko; S. G. Biedron; J. N. Galayda; E. Gluskin; J. Jagger; V. Sajaev; I. Vasserman

2000-08-11T23:59:59.000Z

199

Probing Spatial, Electronic Structures with X-ray Scattering, Spectroscopic  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Probing Spatial, Electronic Structures with X-ray Scattering, Spectroscopic Probing Spatial, Electronic Structures with X-ray Scattering, Spectroscopic Techniques Wednesday, September 5, 2012 - 10:45am SLAC, Bldg. 137, Room 226 Gang Chen Seminar: Structures at atomic scales are traditionally determined through X-ray crystallography that amplifies scattering intensities by introducing spatial periodicity. For amorphous materials and many macromolecules, such as viruses, proteins and biofilms, it is hard to determine structures due to their incapability to crystallize or change of configuration during crystallization. In this talk, I will present the application of X-ray reflectivity and a newly developed fluctuation X-ray scattering technique to study the structures of lipid membranes and randomly oriented nanoparticles. Three different types of domain registrations occurring with

200

Burning plasmas with ultrashort soft-x-ray flashing  

SciTech Connect (OSTI)

Fast ignition with narrow-band coherent x-ray pulses has been revisited for cryogenic deuterium-tritium (DT) plasma conditions achieved on the OMEGA Laser System. In contrast to using hard-x-rays (hv = 3-6 keV) proposed in the original x-ray fast-ignition proposal, we find that soft-x-ray sources with hv Almost-Equal-To 500 eV photons can be suitable for igniting the dense DT-plasmas achieved on OMEGA. Two-dimensional radiation-hydrodynamics simulations have identified the break-even conditions for realizing such a 'hybrid' ignition scheme (direct-drive compression with soft-x-ray heating) with 50-{mu}m-offset targets: {approx}10 ps soft-x-ray pulse (hv Almost-Equal-To 500 eV) with a total energy of 500-1000 J to be focused into a 10 {mu}m spot-size. A variety of x-ray pulse parameters have also been investigated for optimization. It is noted that an order of magnitude increase in neutron yield has been predicted even with x-ray energy as low as {approx}50 J. Scaling this idea to a 1 MJ large-scale target, a gain above {approx}30 can be reached with the same soft-x-ray pulse at 1.65 kJ energy. Even though such energetic x-ray sources do not currently exist, we hope that the proposed ignition scheme may stimulate efforts on generating powerful soft-x-ray sources in the near future.

Hu, S. X.; Goncharov, V. N.; Skupsky, S. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

2012-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

X-ray Absorption Spectroscopy  

SciTech Connect (OSTI)

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

Yano, Junko; Yachandra, Vittal K.

2009-07-09T23:59:59.000Z

202

X-ray fluorescence mapping  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

biololgical cells, over the measurement of impurities in solar cells, to the rare earth content of geological materials. A somewhat 'typical' layout for a X-ray fluorescence...

203

The radiation-tolerant x-ray monitor  

SciTech Connect (OSTI)

A vacuum photoelectric detector (monitor) (VPD) designed for plasma tomography, megnetohydrodynamics monitoring, and imaging with the help of thermal x-ray radiation on the ITER facility is described. Laboratory experiments demonstrate that VPD has high sensitivity to thermal x rays and low sensitivity to hard gamma rays and neutrons. The results of tests of a prototype of this monitor on a {sup 60}Co source of gamma rays, on nuclear reactor and its calibration using radiation from an x-ray tube, and tests of its serviceability on the T-10 facility are presented.

Gott, Yu. V.; Stepanenko, M. M. [Nuclear Fusion Institute, Russian Research Center 'Kurchatov Institute', Kurchatov Sq. 1, Moscow 123182 (Russian Federation)

2008-10-15T23:59:59.000Z

204

Cryogenic X-Ray Diffraction Microscopy for Biological Samples  

Science Journals Connector (OSTI)

X-ray diffraction microscopy (XDM) is well suited for nondestructive, high-resolution biological imaging, especially for thick samples, with the high penetration power of x rays and without limitations imposed by a lens. We developed nonvacuum, cryogenic (cryo-) XDM with hard x rays at 8 keV and report the first frozen-hydrated imaging by XDM. By preserving samples in amorphous ice, the risk of artifacts associated with dehydration or chemical fixation is avoided, ensuring the imaging condition closest to their natural state. The reconstruction shows internal structures of intact D. radiodurans bacteria in their natural contrast.

Enju Lima; Lutz Wiegart; Petra Pernot; Malcolm Howells; Joanna Timmins; Federico Zontone; Anders Madsen

2009-11-05T23:59:59.000Z

205

Cryogenic X-ray Diffraction Microscopy for Biological Samples  

SciTech Connect (OSTI)

X-ray diffraction microscopy (XDM) is well suited for nondestructive, high-resolution biological imaging, especially for thick samples, with the high penetration power of x rays and without limitations imposed by a lens. We developed nonvacuum, cryogenic (cryo-) XDM with hard x rays at 8 keV and report the first frozen-hydrated imaging by XDM. By preserving samples in amorphous ice, the risk of artifacts associated with dehydration or chemical fixation is avoided, ensuring the imaging condition closest to their natural state. The reconstruction shows internal structures of intact D. radiodurans bacteria in their natural contrast.

E Lima; L Wiegart; P Pernot; M Howells; J Timmins; F Zontone; A Madsen

2011-12-31T23:59:59.000Z

206

Optics-free x-ray FEL oscillator  

SciTech Connect (OSTI)

There is a need for an Optics-Free FEL Oscillators (OFFELO) to further the advantages of free-electron lasers and turning them in fully coherent light sources. While SASE (Self-Amplified Spontaneous Emission) FELs demonstrated the capability of providing very high gain and short pulses of radiation and scalability to the X-ray range, the spectra of SASE FELs remains rather wide ({approx}0.5%-1%) compared with typical short wavelengths FEL-oscillators (0.01%-0.0003% in OK-4 FEL). Absence of good optics in VUV and X-ray ranges makes traditional oscillator schemes with very high average and peak spectral brightness either very complex or, strictly speaking, impossible. In this paper, we discuss lattice of the X-ray optics-free FEL oscillator and present results of initial computer simulations of the feedback process and the evolution of FEL spectrum in X-ray OFFELO. We also discuss main limiting factors and feasibility of X-ray OFFELO.

Litvinenko, V.N.; Hao, Y.; Kayran, D.; Trbojevic, D.

2011-03-28T23:59:59.000Z

207

Search for Photon-Photon Elastic Scattering in the X-ray Region  

E-Print Network [OSTI]

We report the first results of a search for real photon-photon scattering using X rays. A novel system is developed to split and collide X-ray pulses by applying interferometric techniques. A total of $6.5\\times10^{5}$ pulses (each containing about $10^{11}$ photons) from an X-ray Free-Electron Laser are injected into the system. No scattered events are observed, and an upper limit of $1.7\\times 10^{-24}$ ${\\rm m^{2}}$ (95% C.L.) is obtained on the photon-photon elastic scattering cross section at 6.5 keV.

T. Inada; T. Yamaji; S. Adachi; T. Namba; S. Asai; T. Kobayashi; K. Tamasaku; Y. Tanaka; Y. Inubushi; K. Sawada; M. Yabashi; T. Ishikawa

2014-04-18T23:59:59.000Z

208

X-ray shearing interferometer  

DOE Patents [OSTI]

An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

Koch, Jeffrey A. (Livermore, CA)

2003-07-08T23:59:59.000Z

209

Femtosecond diffractive imaging with a soft-X-ray free-electron...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Synchrotron Radiation Laboratory, Uppsala University, the Deutsches Elektronen-Synchroton (DESY), and Technische Universitt Berlin. The FLASH FEL began operations at DESY...

210

Science Driven Requirements for Seeded Soft X-ray Free Electron...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Wednesday, October 1, 2014 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Fulvio Parmigiani (Elettra Sincrotrone Trieste) Program Description Starting from the...

211

Accurate macromolecular structures using minimal measurements from X-ray free-electron lasers  

SciTech Connect (OSTI)

Diffraction patterns from thermolysin microcrystals and one dark run, collected in December 2011. This data was used for metrology calibration and general cctbx.xfel development.

Hattne, Hattne

2014-03-04T23:59:59.000Z

212

De novo protein crystal structure determination from X-ray free-electron laser data  

SciTech Connect (OSTI)

Serial femtosecond crystallography (SFX) data of microcrystals of a lysozyme gadolinium derivative. The data was used to demonstrate de-novo phasing by single anomalous dispersion.

Barends, Thomas, R.M.

2013-11-25T23:59:59.000Z

213

Accurate macromolecular structures using minimal measurements from X-ray free-electron lasers  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

Diffraction patterns from thermolysin microcrystals and one dark run, collected in December 2011. This data was used for metrology calibration and general cctbx.xfel development.

Hattne, Hattne

214

De novo protein crystal structure determination from X-ray free-electron laser data  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

Serial femtosecond crystallography (SFX) data of microcrystals of a lysozyme gadolinium derivative. The data was used to demonstrate de-novo phasing by single anomalous dispersion.

Barends, Thomas, R.M.

215

SciTech Connect: Compact X-ray Free Electron Laser from a Laser...  

Office of Scientific and Technical Information (OSTI)

Gradient Undulator Compact laser-plasma accelerators can produce high energy electron beams with low emittance, high peak current but a rather large energy spread. The large...

216

R&D for a Soft X-Ray Free Electron Laser Facility  

E-Print Network [OSTI]

Quantum-degenerate Electron Source, Physical Review LettersHigh brightness electron source, beam instrumentation andFEL Requires high rep-rate electron source Beam switchyard

Staples, John

2009-01-01T23:59:59.000Z

217

Optics for X-Ray Laser and Laser Plasma Soft X-Ray Radiation  

Science Journals Connector (OSTI)

Focusing X-ray grazing incidence optics for X-ray laser and laser plasma soft X-ray radiation has been studied. ... computer code. Parabolic axisymmetric mirror for focusing Princeton X-ray laser beam and ellipso...

L. Pina; A. Inneman; R. Hudec

1996-01-01T23:59:59.000Z

218

Sub-Picosecond X-Ray Pulses Workshop  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

International Workshop on the Interactions of Intense Sub-Picosecond X-Ray International Workshop on the Interactions of Intense Sub-Picosecond X-Ray Pulses with Matter (SLAC, January 23-24, 1997) During the last five years studies have been conducted at the Stanford Linear Accelerator Center (SLAC) and the Deutsches Elektronen-Synchrotron (DESY) in Hamburg concerning the feasibility of driving an Angstrom-wavelength Free-Electron Laser (FEL) with a high energy rf linac. Recent promising advances in linac, rf gun, and insertion device technologies make it seem likely that such a device can be constructed. The output radiation predicted for this type of source will be characterized by full transverse coherence, extreme pulse brevity (~50-100 fs), high peak power (10-100 GW), and very high unfocused peak power density (0.4-4.1013

219

Searching for plasmas with anomalous dispersion in the soft X-ray regime  

SciTech Connect (OSTI)

Over the last decade the electron density of plasmas has been measured using X-ray laser interferometers in the 14 to 47 nm wavelength regime. With the same formula used in decades of experiments with optical interferometers, the data analysis assumes the index of refraction is due only to the free electrons, which makes the index less than one. Over the last several years, interferometer experiments in C, Al, Ag, and Sn plasmas have observed plasmas with index of refraction greater than one at 14 or 47 nm and demonstrated unequivocally that the usual formula for calculating the index of refraction is not always valid as the contribution from bound electrons can dominate the free electrons in certain cases. In this paper we search for other materials with strong anomalous dispersion that could be used in X-ray laser interferometer experiments to help understand this phenomena. An average atom code is used to calculate the plasma properties. This paper discusses the calculations of anomalous dispersion in Ne and Na plasmas near 47 nm and Xe plasmas near 14 nm. With the advent of the FLASH X-ray free electron laser in Germany and the LCLS X-FEL coming online at Stanford in 2 years the average atom code will be an invaluable tool to explore plasmas at higher X-ray energy to identify potential experiments for the future. During the next decade X-ray free electron lasers and other X-ray sources will be used to probe a wider variety of plasmas at higher densities and shorter wavelengths so understanding the index of refraction in plasmas will be even more essential.

Nilsen, J; Johnson, W R; Cheng, K T

2007-08-24T23:59:59.000Z

220

following an electron bunch for free electron laser  

SciTech Connect (OSTI)

A video artist's ultra-slow-motion impression of an APEX-style electron gun firing a continuous train of electron bunches into a superconducting linear accelerator (in reality this would happen a million times a second). As they approach the speed of light the bunches contract, maintaining beam quality. After acceleration, the electron bunches are diverted into one or more undulators, the key components of free electron lasers. Oscillating back and forth in the changing magnetic field, they create beams of structured x-ray pulses. Before entering the experimental areas the electron bunches are diverted to a beam dump. (Animation created by Illumina Visual, http://www.illuminavisual.com/, for Lawrence Berkeley National Laboratory. Music for this excerpt, "Feeling Dark (Behind The Mask)" is by 7OOP3D http://ccmixter.org/files/7OOP3D/29126 and is licensed under a Creative Commons license: http://creativecommons.org/licenses/by-nc/3.0/)

None

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

X-ray Imaging Workshop  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Imaging and Spectro-microscopy: Imaging and Spectro-microscopy: the Present and the Future Stanford Synchrotron Radiation Laboratory October 8-9, 2002 Organizers: John Miao & Keith Hodgson A workshop on "X-ray Imaging and Spectro-microscopy: the Present and the Future" was held on October 8-9, 2002. This workshop, organized by John Miao (SSRL) and Keith Hodgson (SSRL) provided a forum to discuss the scientific applications of a variety of imaging and spectro-microscopic techniques, including photoemission electron microscopy (PEEM), angle resolved photoemission spectroscopy (ARPES), coherent diffraction imaging, x-ray microscopy, micro-tomography, holographic imaging, and x-ray micro-probe. Twelve invited speakers discussed the important scientific applications of these techniques, and also predicted the future scientific directions with the advance of instrumentation and x-ray sources. The workshop was well attended with over fifty registered attendees.

222

Miniature x-ray source  

DOE Patents [OSTI]

A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

Trebes, James E. (Livermore, CA); Bell, Perry M. (Tracy, CA); Robinson, Ronald B. (Modesto, CA)

2000-01-01T23:59:59.000Z

223

X-ray Stacking 2008-Apr-22 Astrostats X-ray Stacking  

E-Print Network [OSTI]

X-ray Stacking 2008-Apr-22 Astrostats X-ray Stacking Tom Aldcroft SAO/CXC #12;X-ray Stacking 2008 analysis for a sample Stacking ­ mean properties of sample Chandra X-ray data (faint point sources) are photon-limited with low background => stacking in X-rays is very effective #12;X-ray Stacking 2008-Apr-22

Wolfe, Patrick J.

224

STATE-DEPENDENT ORBITAL MODULATION OF X-RAYS IN CYG X-3  

SciTech Connect (OSTI)

We analyze all of the available RXTE observations of Cyg X-3 in order to investigate the connection between the central X-ray source and its surrounding environment. The hardness-intensity diagram of Cyg X-3 displays a 'shoe' shape rather than the Q-type shape commonly seen in other black hole X-ray binary, and exhibits no apparent hysteresis effect. During the {gamma}-ray outbursts, no existing data are located in the hard and intermediate states, which suggest the absence of a significant population of non-thermal electrons when the source is in these states. For the first time, we present the orbital modulation of the X-ray light curve (LC) of all five states. The different energy band LCs are in phase with each other in all five states, and the modulation amplitude of both soft and hard X-ray LCs monotonously increases with decreasing hardness from hard to soft non-thermal states. We confirm that the modulation depth decreases with increasing energy in the hard, intermediate, and very high states, as originally reported by Zdziarski et al. However, in the soft non-thermal state, the hard X-ray modulation strength significantly increases and is even larger than the soft X-ray one. Our results rule out both wind absorption and jet origins of the hard X-ray LC modulation in the soft non-thermal state, and challenge our understanding of the states of Cyg X-3.

Weng, Shan-Shan; Zhang, Shuang-Nan; Ge, Ming-Yu; Li, Jian; Zhang, Shu, E-mail: zhangsn@ihep.ac.cn, E-mail: wengss@ihep.ac.cn [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2013-01-20T23:59:59.000Z

225

High Redshift X-Ray Selected Quasars: CXOCY J125304.0-090737 joins the club  

E-Print Network [OSTI]

We present a new X-ray selected high redshift quasar CXOCY J125304.0-090737 at z=4.179, discovered by the Calan-Yale Deep Extragalactic Research (CYDER) Survey. This quasar is the fifth X-ray selected high redshift radio quiet quasar ($z>4$) found so far. Here, we present its observed properties which are characterized by its relative optical and X-ray faintness, its X-ray hardness and its X-ray strength compared to optically selected quasars at high redshift. We also compare the X-ray selected high redshift radio quiet quasars to their optically selected counterparts. We find that the optical to X-ray spectral slope, $\\alpha_{ox}$, is statistically harder (more X-ray luminous) for the X-ray selected radio quiet quasars than for the optically selected ones. This result, given the different range of rest frame ultraviolet luminosities studied and the selection of the samples, is consistent with the previously found correlation between X-ray and rest frame ultraviolet luminosities and would extend that result to a much wider luminosity range at high redshift. Finally, we discuss the prospects of unveiling the quasar luminosity function at high redshifts using X-ray surveys. The discovery of a high redshift object in the first field of our survey program provides suggestive evidence that X-ray selected surveys may identify more such objects than would be expected from an extrapolation of the optical luminosity function.

F. J. Castander; E. Treister; T. J. Maccarone; P. S. Coppi; J. Maza; S. E. Zepf; R. Guzman

2003-01-29T23:59:59.000Z

226

Center for X-Ray Optics, 1991  

SciTech Connect (OSTI)

This report discusses: Soft-X-Ray imaging with zone-plate lenses; multilayer reflective optics; and spectroscopy with x-rays.

Not Available

1992-03-01T23:59:59.000Z

227

SMB, X-ray Absorption Spectroscopy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Absorption Spectroscopy X-ray Absorption Spectroscopy X-ray absorption spectroscopy (XAS) is a well-established technique for simultaneous local geometric and electronic structure...

228

Tokamak x ray diagnostic instrumentation  

SciTech Connect (OSTI)

Three classes of x-ray diagnostic instruments enable measurement of a variety of tokamak physics parameters from different features of the x-ray emission spectrum. (1) The soft x-ray (1 to 50 keV) pulse-height-analysis (PHA) diagnostic measures impurity concentrations from characteristic line intensities and the continuum enhancement, and measures the electron temperature from the continuum slope. (2) The Bragg x-ray crystal spectrometer (XCS) measures the ion temperature and neutral-beam-induced toroidal rotation velocity from the Doppler broadening and wavelength shift, respectively, of spectral lines of medium-Z impurity ions. Impurity charge state distributions, precise wavelengths, and inner-shell excitation and recombination rates can also be studied. X rays are diffracted and focused by a bent crystal onto a position-sensitive detector. The spectral resolving power E/..delta..E is greater than 10/sup 4/ and time resolution is 10 ms. (3) The x-ray imaging system (XIS) measures the spatial structure of rapid fluctuations (0.1 to 100 kHZ) providing information on MHD phenomena, impurity transport rates, toroidal rotation velocity, plasma position, and the electron temperature profile. It uses an array of silicon surface-barrier diodes which view different chords of the plasma through a common slot aperture and operate in current (as opposed to counting) mode. The effectiveness of shields to protect detectors from fusion-neutron radiation effects has been studied both theoretically and experimentally.

Hill, K.W.; Beiersdorfer, P.; Bitter, M.; Fredrickson, E.; Von Goeler, S.; Hsuan, H.; Johnson, L.C.; Liew, S.L.; McGuire, K.; Pare, V.

1987-01-01T23:59:59.000Z

229

Demonstration of Successful X-ray Thomson Scattering Using Picosecond K-(alpha) X-ray Sources for the Characterization of Dense Heated Matter  

SciTech Connect (OSTI)

We discuss the first successful K-{alpha} x-ray Thomson scattering experiment from solid density plasmas for use as a diagnostic in determining the temperature, density, and ionization state of warm dense matter with picosecond resolution. The development of this source as a diagnostic and stringent requirements for successful K-{alpha} x-ray Thomson scattering are addressed. Data for the experimental techniques described in this paper [1] suggest the capability of single shot characterization of warm dense matter and the ability to use this scattering source at future Free Electron Lasers (FEL) where comparable scattering signal levels are predicted.

Kritcher, A; Neumayer, P; Lee, H J; Doeppner, T; Falcone, R; Glenzer, S; Morse, E C

2008-05-05T23:59:59.000Z

230

Vacuum photodiode detectors for soft x-ray ITER plasma tomography  

SciTech Connect (OSTI)

A special type of vacuum photodiode detector (VPD) for x-ray tomography of (ITER) plasma is described. Laboratory experiments demonstrate that VPD has high sensitivity to thermal x-rays and low sensitivity to hard gamma rays and neutrons. It was shown that in ITER environment the signal due to thermal x-rays will surpass the background signal by more than a factor of 100.

Gott, Yu.V.; Stepanenko, M.M. [RRC, Nuclear Fusion Institute, Kurchatov sq.1, Moscow, 123182 (Russian Federation)

2005-07-15T23:59:59.000Z

231

X-ray Emission from Massive Stars  

E-Print Network [OSTI]

X-ray Emission from Massive Stars David Cohen Department of Physics and Astronomy Swarthmore be related to the production of X-rays on massive stars. If so, massive stars' X-rays are much different than those found our own Sun and other cooler stars like the Sun that produce X-rays via magnetic activity

Cohen, David

232

X-ray Emission from Massive Stars  

E-Print Network [OSTI]

X-ray Emission from Massive Stars David Cohen Department of Physics and Astronomy Swarthmore #12;What is the mechanism by which massive stars produce x-rays? New results from the Chandra X-ray Observatory ­ high-resolution x-ray spectroscopy: measuring Doppler broadening in emission lines Testing

Cohen, David

233

Compact x-ray source and panel  

DOE Patents [OSTI]

A compact, self-contained x-ray source, and a compact x-ray source panel having a plurality of such x-ray sources arranged in a preferably broad-area pixelized array. Each x-ray source includes an electron source for producing an electron beam, an x-ray conversion target, and a multilayer insulator separating the electron source and the x-ray conversion target from each other. The multi-layer insulator preferably has a cylindrical configuration with a plurality of alternating insulator and conductor layers surrounding an acceleration channel leading from the electron source to the x-ray conversion target. A power source is connected to each x-ray source of the array to produce an accelerating gradient between the electron source and x-ray conversion target in any one or more of the x-ray sources independent of other x-ray sources in the array, so as to accelerate an electron beam towards the x-ray conversion target. The multilayer insulator enables relatively short separation distances between the electron source and the x-ray conversion target so that a thin panel is possible for compactness. This is due to the ability of the plurality of alternating insulator and conductor layers of the multilayer insulators to resist surface flashover when sufficiently high acceleration energies necessary for x-ray generation are supplied by the power source to the x-ray sources.

Sampayon, Stephen E. (Manteca, CA)

2008-02-12T23:59:59.000Z

234

Ultrafast X-ray Absorption Spectroscopy using Laser-Driven Electron X-ray Sources (LEXS)  

E-Print Network [OSTI]

: ultrafast x-rays, x-ray absorption spectroscopy, terawatt lasers, ultrafast reaction dynamics, atomic motion atomic motion by scrutinizing the changes in x- ray absorption spectra during reactions. FirstUltrafast X-ray Absorption Spectroscopy using Laser-Driven Electron X-ray Sources (LEXS) Guangjun

Guo, Ting

235

Free-Electron Laser | Jefferson Lab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Research Inspecting an injector assembly at Jefferson Lab's Free-Electron Laser. A D D I T I O N A L L I N K S: FEL Users FEL Description JLAMP Proposal Applications FEL News...

236

X-ray instrumentation for the photon factory  

SciTech Connect (OSTI)

The Photon Factory is one of the world's largest synchroton radiation light sources, the beam lines of which supply intense sources of vacuum UV, soft and hard X-rays. About 30 measuring instruments have been purpose-built, and this book describes the development and construction of the X-ray instrumentation. Given the multifunctional nature of the Photon Factory, it may be expected that the instrumentation serving it fulfills a variety of purposes including: reflection imaging systems; diffraction grating fabrication; monochromators; polarizers; analyzers; detectors; data collection systems; cameras; and goniometers.

Hosoya, S.; Iitaka, Y.; Hashizume, H.

1987-01-01T23:59:59.000Z

237

Focused X-ray source  

DOE Patents [OSTI]

Disclosed is an intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator. 8 figs.

Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Maccagno, P.

1990-08-21T23:59:59.000Z

238

Measurements of Ionic Structure in Shock Compressed Lithium Hydride from Ultrafast X-Ray Thomson Scattering  

SciTech Connect (OSTI)

We present the first ultrafast temporally, spectrally, and angularly resolved x-ray scattering measurements from shock-compressed matter. The experimental spectra yield the absolute elastic and inelastic scattering intensities from the measured density of free electrons. Laser-compressed lithium-hydride samples are well characterized by inelastic Compton and plasmon scattering of a K-alpha x-ray probe providing independent measurements of temperature and density. The data show excellent agreement with the total intensity and structure when using the two-species form factor and accounting for the screening of ion-ion interactions.

Kritcher, A. L. [L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Department of Nuclear Engineering, University of California Berkeley, Berkeley, California 94709 (United States); Neumayer, P.; Doeppner, T.; Landen, O. L.; Glenzer, S. H. [L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Brown, C. R. D. [Department of Physics, Imperial College, London SW7 2AZ (United Kingdom); AWE plc., Aldermaston, Reading, RG7 4PR (United Kingdom); Davis, P. [L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Department of Physics, University of California Berkeley, Berkeley, California 94709 (United States); Falcone, R. W.; Lee, H. J. [Department of Physics, University of California Berkeley, Berkeley, California 94709 (United States); Gericke, D. O.; Vorberger, J.; Wuensch, K. [CFSA, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Gregori, G. [Department of Physics, Oxford University, Oxford OX1 3PU (United Kingdom); Holst, B.; Redmer, R. [Universitaet Rostock, Institut fuer Physik, D-18051 Rostock (Germany); Morse, E. C. [Department of Nuclear Engineering, University of California Berkeley, Berkeley, California 94709 (United States); Pelka, A.; Roth, M. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Darmstadt (Germany)

2009-12-11T23:59:59.000Z

239

Free-Electron Laser Targets Fat | Jefferson Lab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Free-Electron Laser Targets Fat April 10, 2006 Free-Electron Laser Scientists Rox Anderson, right, and Free-Electron Laser Scientist Steve Benson, left, discuss laser beam...

240

E-Print Network 3.0 - aspect ratio x-ray Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

London Collection: Physics 100 Single-element elliptical hard x-ray micro-optics Kenneth Evans-Lutterodt, James M. Ablett, Aaron Stein and Chi-Chang Kao Summary: . Dhez, P....

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Thin optic surface analysis for high resolution X-ray telescopes  

E-Print Network [OSTI]

The art of glass developed throughout the years has covered artifacts ranging from crude ornaments to high precision optics used in flat panel displays, hard disk drives, and x-ray telescopes. Methods for manufacturing ...

Akilian, Mireille

2004-01-01T23:59:59.000Z

242

13 - X-ray and Neutron Scattering  

Science Journals Connector (OSTI)

Abstract This chapter describes the use of neutrons and X-rays as probes in the study of structural and dynamic properties of metallic materials. Crystalline materials are characterized by their diffraction peaks related to their average crystallographic structure. In real crystals, locally displaced atoms and chemically (or isotopically for neutrons) different species may lead not only to changes of peak shapes and positions, but also to additional (diffuse) scattering between Bragg peak, including scattering around the primary beam (small-angle scattering). All these features can be used to extract information about the state of a sample, its compositional and structural variations on a scale depending on the scattering, in static and time-resolved kinetic studies. Energy-resolved scattering also offers an insight into solid-state dynamics on a microscopic scale. Some of the most important methods will be described and illustrated by instructive examples. The presentation offers a combined view of neutron and X-ray scattering, with the necessary simplifications dictated by space limitations. The special properties of thermal neutrons and of hard X-rays (now widely available at synchrotron radiation sources), their mutual combination, and combinations with other methods, in particular electron microscopy, offer ample opportunity to better understand and control materials properties. After a brief introduction to scattering from real crystals and some general ideas about long-range strains and Bragg peaks, the vicinity of Bragg peaks (displacement scattering at large scattering angles), the scattering far away from Bragg peaks (chemical heterogeneities, short-range order), and, in greater detail, small-angle scattering (which is not sensitive to the extent of crystallinity, but to nanoscale variations of chemical composition and of magnetization, precipitation) will be described, along with classical and more recent applications related to short-range ordering and precipitation in bulk and nanostructured alloys. Some other fields are only briefly addressed (grazing-incidence studies of surfaces, radiography, absorption spectroscopies, coherent X-rays). The final section offers some information on the influence of defects on lattice dynamics and on (slow) diffusive motion in materials.

Gernot Kostorz

2014-01-01T23:59:59.000Z

243

Interferometric phase detection at x-ray energies via Fano resonance control  

E-Print Network [OSTI]

Modern x-ray light sources promise access to structure and dynamics of matter in largely unexplored spectral regions. However, the desired information is encoded in the light intensity and phase, whereas detectors register only the intensity. This phase problem is ubiquitous in crystallography and imaging, and impedes the exploration of quantum effects at x-ray energies. Here, we demonstrate phase-sensitive measurements characterizing the quantum state of a nuclear two-level system at hard x-ray energies. The nuclei are initially prepared in a superposition state. Subsequently, the relative phase of this superposition is interferometrically reconstructed from the emitted x-rays. Our results form a first step towards x-ray quantum state tomography, and provide new avenues for structure determination and precision metrology via x-ray Fano interference.

K. P. Heeg; C. Ott; D. Schumacher; H. -C. Wille; R. Röhlsberger; T. Pfeifer; J. Evers

2014-11-06T23:59:59.000Z

244

Physical origin of X-ray flares following GRBs  

E-Print Network [OSTI]

One of the major achievements of Swift is the discovery of the erratic X-ray flares harboring nearly half of gamma-ray bursts (GRBs), both for long-duration and short-duration categories, and both for traditional hard GRBs and soft X-ray flashes (XRFs). Here I review the arguments in support of the suggestion that they are powered by reactivation of the GRB central engine, and that the emission site is typically ``internal'', i.e. at a distance within the forward shock front. The curvature effect that characterizes the decaying lightcurve slope during the fading phase of the flares provides an important clue. I will then discuss several suggestions to re-start the GRB central engine and comment on how future observations may help to unveil the physical origin of X-ray flares.

Bing Zhang

2006-02-25T23:59:59.000Z

245

X-ray Phase Contrast analysis - Digital wavefront development  

SciTech Connect (OSTI)

Optical schemes that enable imaging of the phase shift produced by an object have become popular in the x-ray region, where phase can be the dominant contrast mechanism. The propagation-based technique consists of recording the interference pattern produced by choosing one or several sample-to-detector distances. Pioneering studies, carried out making use of synchrotron radiation, demonstrated that this technique results in a dramatic increase of image contrast and detail visibility, allowing the detection of structures invisible with conventional techniques. An experimental and theoretical study of in-line hard x-ray phase-contrast imaging had been performed. The theoretical description of the technique is based on Fresnel diffraction. As an illustration of the potential of this quantitative imaging technique, high-resolution x-ray phase contrast images of simple objects will be presented.

Idir, Mourad [Metrology Beamline, Synchrotron SOLEIL, Gif-sur-Yvette (France); Potier, Jonathan [Phaseview, Palaiseau (France); Universite Paul Sabatier-Toulouse III, Metrology Beamline, Synchrotron SOLEIL, Gif-sur-Yvette (France); Fricker, Sebastien [Phaseview, Palaiseau (France); Snigirev, Anatoly; Snigireva, Irina [ESRF, Grenoble (France); Modi, M. H. [X-ray Optics Section, Raja Ramanna Centre for Advanced Technology, Indore (India)

2010-06-23T23:59:59.000Z

246

NuSTAR Observations of X-Ray Binaries  

E-Print Network [OSTI]

As of 2014 August, the Nuclear Spectroscopic Telescope Array (NuSTAR) had observed ~30 X-ray binaries either as part of the planned program, as targets of opportunity, or for instrument calibration. The main science goals for the observations include probing the inner part of the accretion disk and constraining black hole spins via reflection components, providing the first observations of hard X-ray emission from quiescent Low Mass X-ray Binaries (LMXBs), measuring cyclotron lines from accreting pulsars, and studying type I X-ray bursts from neutron stars. Here, we describe the science objectives in more depth and give an overview of the NuSTAR observations that have been carried out to achieve the objectives. These include observation of four "IGR" High Mass X-ray Binaries (HMXBs) discovered by INTEGRAL. We also summarize the results that have been obtained and their implications. Among the IGR HMXBs, we focus on the discovery of a cyclotron line in the spectrum of IGR J17544-2619.

Tomsick, John A; Fuerst, Felix; Harrison, Fiona; Miyasaka, Hiromasa; Tendulkar, Shriharsh; Bhalerao, Varun; Chakrabarty, Deepto; King, Ashley; Miller, Jon M; Natalucci, Lorenzo; Stern, Daniel

2015-01-01T23:59:59.000Z

247

Microgap x-ray detector  

DOE Patents [OSTI]

An x-ray detector which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope.

Wuest, Craig R. (Danville, CA); Bionta, Richard M. (Livermore, CA); Ables, Elden (Livermore, CA)

1994-01-01T23:59:59.000Z

248

Chest x-Rays | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Chest x-Rays Chest x-Rays Chest x-Rays Chest X-ray B-Reading The B-reading is a special reading of a standard chest x-ray film performed by a physician certified by the National Institute for Occupational Safety and Health (NIOSH). The reading looks for changes on the chest x-ray that may indicate exposure and disease caused by agents such as asbestos or silica. The B-reading is considered a special reading because doctors who are certified by NIOSH to perform B-readings use a specific protocol to read and record the findings as developed by the International Labour Organization (ILO). The ILO's protocol provides rules for systematically examining the x-ray in a step-by-step method and recording certain abnormalities or changes on the chest x-ray that can be attributable to

249

Producing X-rays at the APS  

ScienceCinema (OSTI)

An introduction and overview of the Advanced Photon Source at Argonne National Laboratory, the technology that produces the brightest X-ray beams in the Western Hemisphere, and the research carried out by scientists using those X-rays.

None

2013-04-19T23:59:59.000Z

250

SMB, X-ray Fluorescence Imaging  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Fluorescence Imaging X-ray Fluorescence Imaging X-ray fluorescence imaging utilizes the high brightness of SPEAR3 and focused beam generated by the uses of K-B optics, capillaries...

251

EVIDENCE OF NON-THERMAL X-RAY EMISSION FROM HH 80  

SciTech Connect (OSTI)

Protostellar jets appear at all stages of star formation when the accretion process is still at work. Jets travel at velocities of hundreds of km s{sup –1}, creating strong shocks when interacting with the interstellar medium. Several cases of jets have been detected in X-rays, typically showing soft emission. For the first time, we report evidence of hard X-ray emission possibly related to non-thermal processes not explained by previous models of the post-shock emission predicted in the jet/ambient interaction scenario. HH 80 is located at the south head of the jet associated with the massive protostar IRAS 18162-2048. It shows soft and hard X-ray emission in regions that are spatially separated, with the soft X-ray emission region situated behind the region of hard X-ray emission. We propose a scenario for HH 80 where soft X-ray emission is associated with thermal processes from the interaction of the jet with denser ambient matter and hard X-ray emission is produced by synchrotron radiation at the front shock.

López-Santiago, J. [Instituto de Matemática Interdisciplinar, S. D. Astronomía y Geodesia, Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)] [Instituto de Matemática Interdisciplinar, S. D. Astronomía y Geodesia, Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Peri, C. S.; Benaglia, P. [Instituto Argentino de Radioastronomía (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina)] [Instituto Argentino de Radioastronomía (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina); Bonito, R. [Dipartimento di Fisica e Chimica, Università di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy)] [Dipartimento di Fisica e Chimica, Università di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy); Miceli, M. [INAF-Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy)] [INAF-Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy); Albacete-Colombo, J. F. [Universidad Nacional del COMAHUE, Monseñor Esandi y Ayacucho, 8500 Viedma, Río Negro (Argentina)] [Universidad Nacional del COMAHUE, Monseñor Esandi y Ayacucho, 8500 Viedma, Río Negro (Argentina); De Castro, E. [Dpto. de Astrofísica y CC. de la Atmósfera, Universidad Complutense de Madrid, E-28040 Madrid (Spain)] [Dpto. de Astrofísica y CC. de la Atmósfera, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

2013-10-20T23:59:59.000Z

252

Chandra X-ray Observatory Center  

E-Print Network [OSTI]

Chandra X-ray Observatory Center Harvard-Smithsonian Center for Astrophysics 60 Garden St in hot gas about 250 million light years from Earth. (Credit: X-ray: NASA/CXC/SAO/E.Bulbul, et al-Newton has revealed a mysterious X-ray signal in the data. This signal is represented in the circled data

253

X-Ray Absorption Spectroscopy of Metallobiomolecules  

E-Print Network [OSTI]

2/9/07 1 X-Ray Absorption Spectroscopy of Metallobiomolecules The Outskirts of Structural Biology 9, 07] This is a tutorial about the use of X-ray Absorption Spectroscopy (XAS) in biology, RG; Eisenberger, P; Kincaid, BM "X-ray Absorption Spectroscopy of Biological Molecules" Annu. Rev

Scott, Robert A.

254

Chandra X-ray Observatory Center  

E-Print Network [OSTI]

Chandra X-ray Observatory Center Harvard-Smithsonian Center for Astrophysics 60 Garden St million light years from Earth. (Credit: X-ray: NASA/CXC/Wesleyan Univ./R.Kilgard, et al; Optical: NASA with optical data from the Hubble Space Telescope (red, green, and blue). The X-ray data reveal hundreds

255

X-ray Spectroscopy of Cool Stars  

E-Print Network [OSTI]

High-resolution X-ray spectroscopy has addressed not only various topics in coronal physics of stars, but has also uncovered important features relevant for our understanding of stellar evolution and the stellar environment. I summarize recent progress in coronal X-ray spectroscopy and in particular also discuss new results from studies of X-rays from pre-main sequence stars.

M. Guedel

2006-09-11T23:59:59.000Z

256

X-Ray Physics Evan Berkowitz  

E-Print Network [OSTI]

X-Ray Physics Evan Berkowitz Junior, MIT Department of Physics (Dated: October 25, 2006) We measure a variety of phenomena related to X-Ray absorption and production. We present data which conforms within, as are 22 Na electron-positron annhilation lines. The importance of understanding x-rays is demonstrated

257

Chandra X-ray Observatory Center  

E-Print Network [OSTI]

Chandra X-ray Observatory Center Harvard-Smithsonian Center for Astrophysics 60 Garden St 200 million light years from Earth. (Credit: X-ray: NASA/CXC/UAH/M.Sun et al; Optical: NASA, ESA, & the Hubble Heritage Team (STScI/AURA) Caption: This composite image from the Chandra X-ray Observatory (blue

258

X-Ray Absorption Spectroscopy of Metallobiomolecules  

E-Print Network [OSTI]

9/6/09 1 X-Ray Absorption Spectroscopy of Metallobiomolecules The Outskirts of Structural Biology 6, 09] This is a tutorial about the use of X-ray Absorption Spectroscopy (XAS) in biology, RG; Eisenberger, P; Kincaid, BM "X-ray Absorption Spectroscopy of Biological Molecules" Annu. Rev

Scott, Robert A.

259

Chandra X-ray Observatory Center  

E-Print Network [OSTI]

Chandra X-ray Observatory Center Harvard-Smithsonian Center for Astrophysics 60 Garden St. Cambridge, MA 02138 USA http://chandra.harvard.edu Four Supernova Remnants: NASA's Chandra X-ray Observatory's Chandra X-ray Observatory, four newly processed images of supernova remnants dramatically illustrate

260

Combination free electron and gaseous laser  

DOE Patents [OSTI]

A multiple laser having one or more gaseous laser stages and one or more free electron stages. Each of the free electron laser stages is sequentially pumped by a microwave linear accelerator. Subsequently, the electron beam is directed through a gaseous laser, in the preferred embodiment, and in an alternative embodiment, through a microwave accelerator to lower the energy level of the electron beam to pump one or more gaseous lasers. The combination laser provides high pulse repetition frequencies, on the order of 1 kHz or greater, high power capability, high efficiency, and tunability in the synchronous production of multiple beams of coherent optical radiation.

Brau, Charles A. (Los Alamos, NM); Rockwood, Stephen D. (Los Alamos, NM); Stein, William E. (Los Alamos, NM)

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Using Light to Control How X Rays Interact with Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ultrafast x-ray spectroscopy. ALS femtosecond spectroscopy beamline layout. Femtosecond x-ray and laser pulses derive from a single 800-nm laser oscillator. Femtosecond x rays...

262

X-RAY SPECTROMETRY X-Ray Spectrom. 2007; 36: 336342  

E-Print Network [OSTI]

X-RAY SPECTROMETRY X-Ray Spectrom. 2007; 36: 336­342 Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/xrs.980 Fish otolith trace element maps: new approaches with synchrotron microbeam x-ray of elements as they accrete through a fish's life. We apply synchrotron microbeam x-ray fluorescence methods

Limburg, Karin E.

263

X-ray Pulsations in the Supersoft X-ray Binary CAL 83  

E-Print Network [OSTI]

X-ray data reveal that the supersoft X-ray binary CAL 83 exhibits 38.4 minute pulsations at some epochs. These X-ray variations are similar to those found in some novae and are likely to be caused by nonradial pulsations the white dwarf. This is the first detection of pulsations in a classical supersoft X-ray binary.

P. C. Schmidtke; A. P. Cowley

2005-09-28T23:59:59.000Z

264

X-ray Spectroscopy of Cooling Cluster  

SciTech Connect (OSTI)

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

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

2006-01-17T23:59:59.000Z

265

X-ray Spectroscopy of Cooling Clusters  

E-Print Network [OSTI]

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

J. R. Peterson; A. C. Fabian

2005-12-21T23:59:59.000Z

266

The Next Challenge in X-Ray Science: Control of Resonant Electronic  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The Next Challenge in X-Ray Science: Control of Resonant Electronic The Next Challenge in X-Ray Science: Control of Resonant Electronic Processes Wednesday, September 11, 2013 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Joachim Stöhr, LCLS My talk will give a historic perspective of the revolutionary science that was enabled by the advent of high power sources of coherent electromagnetic radiation and the implications for future scientific opportunities with x-ray free electron lasers (X-FELs). The historical journey starts with the development of radar microwave sources in the 1940s that fueled the development of nuclear magnetic resonance (NMR) techniques which by now have led to 6 Nobel Prizes. The theoretical description of NMR as coherent processes between nuclear states by Rabi and Bloch also provided the theoretical basis for the optical laser and its applications. Over the last

267

X-ray lithography using holographic images  

DOE Patents [OSTI]

A non-contact X-ray projection lithography method for producing a desired X-ray image on a selected surface of an X-ray-sensitive material, such as photoresist material on a wafer, the desired X-ray image having image minimum linewidths as small as 0.063 .mu.m, or even smaller. A hologram and its position are determined that will produce the desired image on the selected surface when the hologram is irradiated with X-rays from a suitably monochromatic X-ray source of a selected wavelength .lambda.. On-axis X-ray transmission through, or off-axis X-ray reflection from, a hologram may be used here, with very different requirements for monochromaticity, flux and brightness of the X-ray source. For reasonable penetration of photoresist materials by X-rays produced by the X-ray source, the wavelength X, is preferably chosen to be no more than 13.5 nm in one embodiment and more preferably is chosen in the range 1-5 nm in the other embodiment. A lower limit on linewidth is set by the linewidth of available microstructure writing devices, such as an electron beam.

Howells, Malcolm R. (Berkeley, CA); Jacobsen, Chris (Sound Beach, NY)

1995-01-01T23:59:59.000Z

268

Transverse Coherence of the LCLS X-Ray Beam  

SciTech Connect (OSTI)

Self-amplifying spontaneous radiation free-electron lasers, such as the LCLS or the European X-FEL, rely on the incoherent, spontaneous radiation as the seed for the amplifying process. Though this method overcomes the need for an external seed source one drawback is the incoherence of the effective seed signal. The FEL process allows for a natural growth of the coherence because the radiation phase information is spread out within the bunch due to slippage and diffraction of the radiation field. However, at short wavelengths this spreading is not sufficient to achieve complete coherence. In this presentation we report on the results of numerical simulations of the LCLS X-ray FEL. From the obtained radiation field distribution the coherence properties are extracted to help to characterize the FEL as a light source.

Not Available

2010-12-01T23:59:59.000Z

269

Optical wavelength modulation in free electron lasers  

SciTech Connect (OSTI)

An attribute of the free electron laser (FEL) is the continuous tunability of the optical wavelength by modulation of the electron beam energy. The variation of the wavelength and power of the optical beam is studied as a function of FEL operating parameters. These results will be applied to the Stanford SCA FEL and Boeing FEL.

Mabe, R.M.; Wong, R.K.; Colson, W.B. [Naval Postgraduate School, Monterey, CA (United States)

1995-12-31T23:59:59.000Z

270

Advances in understanding the anomalous dispersion of plasmas in the X-ray regime  

SciTech Connect (OSTI)

Over the last several years we have predicted and observed plasmas with an index of refraction greater than one in the soft X-ray regime. These plasmas are usually a few times ionized and have ranged from low-Z carbon plasmas to mid-Z tin plasmas. Our main computational tool has been the average atom code AVATOMKG that enables us to calculate the index of refraction for any plasma at any wavelength. In the last year we have improved this code to take into account many-atomic collisions. This allows the code to converge better at low frequencies. In this paper we present our search for plasmas with strong anomalous dispersion that could be used in X-ray laser interferometer experiments to help understand this phenomena. We discuss the calculations of anomalous dispersion in Na vapor and Ne plasmas near 47 nm where we predict large effects. We also discuss higher Z plasmas such as Ce and Yb plasmas that look very interesting near 47 nm. With the advent of the FLASH X-ray free electron laser in Germany and the LCLS X-FEL coming online at Stanford in another year we use the average atom code to explore plasmas at higher X-ray energy to identify potential experiments for the future. In particular we look near the K shell lines of near solid carbon plasmas and predict strong effects. During the next decade X-ray free electron lasers and other X-ray sources will be available to probe a wider variety of plasmas at higher densities and shorter wavelengths so understanding the index of refraction in plasmas will be even more essential.

Nilsen, J; Cheng, K T; Johnson, W R

2008-09-24T23:59:59.000Z

271

Development of x-ray photoelectron microscope with an x-ray laser source  

Science Journals Connector (OSTI)

We have constructed an x-ray photoelectron microscopic system with an x-ray laser as an x-ray source. The lasing line is the Li-like Al 3d-4f transition at 15.47 nm where the recombining Al plasma is used as the x-ray laser medium. The beam from the x-ray laser cavity was then focused by using a Schwarzschild mirror coated with Mo/Si multilayers. The x-ray beam size with a diameter less than 0.5 ?m and the estimated photon number of about 2×10 6 ? photons/shot into the spot were achieved.

Tadayuki Ohchi; Naohiro Yamaguchi; Chiemi Fujikawa; Tamio Hara; Katsumi Watanabe; Ibuki Tanaka; Masami Taguchi

2000-01-01T23:59:59.000Z

272

Applications of soft x-ray lasers  

SciTech Connect (OSTI)

The high brightness and short pulse duration of soft x-ray lasers provide unique advantages for novel applications. Imaging of biological specimens using x-ray lasers has been demonstrated by several groups. Other applications to fields such as chemistry, material science, plasma diagnostics, and lithography are beginning to emerge. We review the current status of soft x-ray lasers from the perspective of applications, and present an overview of the applications currently being developed.

Skinner, C.H.

1993-08-01T23:59:59.000Z

273

High speed x-ray beam chopper  

DOE Patents [OSTI]

A fast, economical, and compact x-ray beam chopper with a small mass and a small moment of inertia whose rotation can be synchronized and phase locked to an electronic signal from an x-ray source and be monitored by a light beam is disclosed. X-ray bursts shorter than 2.5 microseconds have been produced with a jitter time of less than 3 ns.

McPherson, Armon (Oswego, IL); Mills, Dennis M. (Naperville, IL)

2002-01-01T23:59:59.000Z

274

Simultaneous Planck, Swift, and Fermi observations of X-ray and gamma-ray selected blazars  

E-Print Network [OSTI]

We present simultaneous Planck, Swift, Fermi, and ground-based data for 105 blazars belonging to three samples with flux limits in the soft X-ray, hard X-ray, and gamma-ray bands. Our unique data set has allowed us to demonstrate that the selection method strongly influences the results, producing biases that cannot be ignored. Almost all the BL Lac objects have been detected by Fermi-LAT, whereas ~40% of the flat-spectrum radio quasars (FSRQs) in the radio, soft X-ray, and hard X-ray selected samples are still below the gamma-ray detection limit even after integrating 27 months of Fermi-LAT data. The radio to sub-mm spectral slope of blazars is quite flat up to ~70GHz, above which it steepens to ~-0.65. BL Lacs have significantly flatter spectra than FSRQs at higher frequencies. The distribution of the rest-frame synchrotron peak frequency (\

Giommi, P; Lahteenmaki, A; Thompson, D J; Capalbi, M; Cutini, S; Gasparrini, D; Gonzalez-Nuevo, J; Leon-Tavares, J; Lopez-Caniego, M; Mazziotta, M N; Monte, C; Perri, M; Raino, S; Tosti, G; Tramacere, A; Verrecchia, F; Aller, H D; Aller, M F; Angelakis, E; Bastieri, D; Berdyugin, A; Bonaldi, A; Bonavera, L; Burigana, C; Burrows, D N; Buson, S; Cavazzuti, E; Chincarini, G; Colafrancesco, S; Costamante, L; Cuttaia, F; D'Ammando, F; de Zotti, G; Frailis, M; Fuhrmann, L; Galeotta, S; Gargano, F; Gehrels, N; Giglietto, N; Giordano, F; Giroletti, M; Keihanen, E; King, O; Krichbaum, T P; Lasenby, A; Lavonen, N; Lawrence, C R; Leto, C; Lindfors, E; Mandolesi, N; Massardi, M; Max-Moerbeck, W; Michelson, P F; Mingaliev, M; Natoli, P; Nestoras, I; Nieppola, E; Nilsson, K; Partridge, B; Pavlidou, V; Pearson, T J; Procopio, P; Rachen, J P; Readhead, A; Reeves, R; Reimer, A; Reinthal, R; Ricciardi, S; Richards, J; Riquelme, D; Saarinen, J; Sajina, A; Sandri, M; Savolainen, P; Sievers, A; Sillanpaa, A; Sotnikova, Y; Stevenson, M; Tagliaferri, G; Takalo, L; Tammi, J; Tavagnacco, D; Terenzi, L; Toffolatti, L; Tornikoski, M; Trigilio, C; Turunen, M; Umana, G; Ungerechts, H; Villa, F; Wu, J; Zacchei, A; Zensus, J A; Zhou, X

2011-01-01T23:59:59.000Z

275

X-ray laser frequency near-doubling and generation of tunable coherent x rays in plasma  

E-Print Network [OSTI]

X-ray laser frequency near-doubling and generation of tunable coherent x rays in plasma P. L plasmas in which efficient x-ray laser frequency near-doubling is expected for a number of available x-ray of coherent x rays and tunable optical radiation may result in tunable coherent x-ray radiation powerful

Kaplan, Alexander

276

Colloid Coalescence with Focused X Rays  

SciTech Connect (OSTI)

We show direct evidence that focused x rays enable us to merge polymer colloidal particles at room temperature. This phenomenon is ascribed to the photochemical scission of colloids with x rays, reducing the molecular weight, glass transition temperature, surface tension, and viscosity of colloids. The observation of the neck bridge growth with time shows that the x-ray-induced colloid coalescence is analogous to viscoelastic coalescence. This finding suggests a feasible protocol of photonic nanofabrication by sintering or welding of polymers, without thermal damage, using x-ray photonics.

Weon, B. M.; Kim, J. T.; Je, J. H. [X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Yi, J. M. [Samsung Advanced Institute of Technology, Yongin, Gyeonggi, 446-712 (Korea, Republic of); Wang, S.; Lee, W.-K. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2011-07-01T23:59:59.000Z

277

X-RAY MICROBEAM SPEECH PRODUCTION DATABASE  

E-Print Network [OSTI]

X-RAY MICROBEAM SPEECH PRODUCTION DATABASE USER'S HANDBOOK Version 1.0 (June 1994) prepared by John . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Chapter Two: XRMB History

278

X-ray laser microscope apparatus  

DOE Patents [OSTI]

A microscope consisting of an x-ray contact microscope and an optical microscope. The optical, phase contrast, microscope is used to align a target with respect to a source of soft x-rays. The source of soft x-rays preferably comprises an x-ray laser but could comprise a synchrotron or other pulse source of x-rays. Transparent resist material is used to support the target. The optical microscope is located on the opposite side of the transparent resist material from the target and is employed to align the target with respect to the anticipated soft x-ray laser beam. After alignment with the use of the optical microscope, the target is exposed to the soft x-ray laser beam. The x-ray sensitive transparent resist material whose chemical bonds are altered by the x-ray beam passing through the target mater GOVERNMENT LICENSE RIGHTS This invention was made with government support under Contract No. De-FG02-86ER13609 awarded by the Department of Energy. The Government has certain rights in this invention.

Suckewer, Szymon (Princeton, NJ); DiCicco, Darrell S. (Plainsboro, NJ); Hirschberg, Joseph G. (Coral Gables, FL); Meixler, Lewis D. (East Windsor, NJ); Sathre, Robert (Princeton, NJ); Skinner, Charles H. (Lawrenceville, NJ)

1990-01-01T23:59:59.000Z

279

Automation in X-Ray Crystallography  

Science Journals Connector (OSTI)

Automation in X-Ray Crystallography ... But in the past few years, automation procedures have been applied to intrinsically superior experimental methods. ...

S.C. ABRAHAMS

1963-06-03T23:59:59.000Z

280

X-Ray Laser Sources for Microscopy  

Science Journals Connector (OSTI)

Progress and prospects in soft X-ray laser development at Princeton are presented. A comparison to plasma and synchrotron sources is made with a...

C. H. Skinner; D. E. Kim; A. Wouters; D. Voorhees; S. Suckewer

1988-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Compound refractive X-ray lens  

DOE Patents [OSTI]

An apparatus and method for focusing X-rays. In one embodiment, his invention is a commercial-grade compound refractive X-ray lens. The commercial-grade compound refractive X-ray lens includes a volume of low-Z material. The volume of low-Z material has a first surface which is adapted to receive X-rays of commercially-applicable power emitted from a commercial-grade X-ray source. The volume of low-Z material also has a second surface from which emerge the X-rays of commercially-applicable power which were received at the first surface. Additionally, the commercial-grade compound refractive X-ray lens includes a plurality of openings which are disposed between the first surface and the second surface. The plurality of openings are oriented such that the X-rays of commercially-applicable power which are received at the first surface, pass through the volume of low-Z material and through the plurality openings. In so doing, the X-rays which emerge from the second surface are refracted to a focal point.

Nygren, David R. (Berkeley, CA); Cahn, Robert (Walnut Creek, CA); Cederstrom, Bjorn (Traellborg, SE); Danielsson, Mats (Stocksund, SE); Vestlund, Jonas (Stockholm, SE)

2000-01-01T23:59:59.000Z

282

X-Ray Science Division (XSD)  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Science Division (XSD) Search Button About Welcome Overview Visiting the APS Mission & Goals Find People Organization Charts Committees Job Openings User Information...

283

2-D X-Ray Focusing by Circular Phase Bragg-Fresnel Lenses at a Bragg Angle Close to ?/2  

Science Journals Connector (OSTI)

Two-dimensional focusing of hard X-rays has been accomplished for the first time by means of a phase Bragg-Fresnel lens with efficiency close to 40%. Images of the radiation region of a conventional X-ray tube...

V. V. Aristov; Yu. A. Basov; A. A. Snigirev; M. Belakhovsky…

1992-01-01T23:59:59.000Z

284

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print Studying the world of the ultrasmall and the ultrafast is at the frontier of scientific research. Two x-ray approaches can be used for ultrafast examinations. The first entails developing sources that have short x-ray pulses such as free-electron lasers and slicing sources, which will provide the ultrafast temporal information. The other approach is to develop a detector that is fast enough to resolve the ultrafast details of the dynamical processes. ALS researchers are taking the second path but adding a spatial resolution capability; that is, they are developing a high-speed x-ray streak camera with high spatial resolution to watch, in real time, the motion of the atoms in materials. So far, a temporal resolution of 233 fs and a spatial resolution of 10 mm have been demonstrated. This is the first time that such a high temporal resolution has been combined with high spatial resolution in a streak camera.

285

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print Studying the world of the ultrasmall and the ultrafast is at the frontier of scientific research. Two x-ray approaches can be used for ultrafast examinations. The first entails developing sources that have short x-ray pulses such as free-electron lasers and slicing sources, which will provide the ultrafast temporal information. The other approach is to develop a detector that is fast enough to resolve the ultrafast details of the dynamical processes. ALS researchers are taking the second path but adding a spatial resolution capability; that is, they are developing a high-speed x-ray streak camera with high spatial resolution to watch, in real time, the motion of the atoms in materials. So far, a temporal resolution of 233 fs and a spatial resolution of 10 mm have been demonstrated. This is the first time that such a high temporal resolution has been combined with high spatial resolution in a streak camera.

286

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print The ALS X-Ray Streak Camera: Bringing the Ultrafast and Ultrasmall into Focus Print Studying the world of the ultrasmall and the ultrafast is at the frontier of scientific research. Two x-ray approaches can be used for ultrafast examinations. The first entails developing sources that have short x-ray pulses such as free-electron lasers and slicing sources, which will provide the ultrafast temporal information. The other approach is to develop a detector that is fast enough to resolve the ultrafast details of the dynamical processes. ALS researchers are taking the second path but adding a spatial resolution capability; that is, they are developing a high-speed x-ray streak camera with high spatial resolution to watch, in real time, the motion of the atoms in materials. So far, a temporal resolution of 233 fs and a spatial resolution of 10 mm have been demonstrated. This is the first time that such a high temporal resolution has been combined with high spatial resolution in a streak camera.

287

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

E-Print Network [OSTI]

In this thesis, I present work spanning a variety of topics relating to neutron star lowmass X-ray binaries (LMXBs) and utilize spectral information from X-ray observations to further our understanding of these sources. ...

Krauss, Miriam Ilana

2007-01-01T23:59:59.000Z

288

Ultraluminous X-ray Sources: The most extreme X-ray binaries  

E-Print Network [OSTI]

1 Ultraluminous X-ray Sources: The most extreme X-ray binaries Luca Zampieri INAF ULXs ­ Lubiana ­ May 11, 2012- LZ #12;6 · X-ray observations of nearby galaxies show a population of pointlike, off-nuclear sources with L >> Ledd for 1 Msun (L>1.0e39 erg/s) UltraLuminous X-ray Sources (e

Â?umer, Slobodan

289

X-ray Diffraction (XRD) 1.0 What is X-ray Diffraction  

E-Print Network [OSTI]

X-ray Diffraction (XRD) · 1.0 What is X-ray Diffraction · 2.0 Basics of Crystallography · 3.0 Production of X-rays · 4.0 Applications of XRD · 5.0 Instrumental Sources of Error · 6.0 Conclusions #12 why the cleavage faces of crystals appear to reflect X-ray beams at certain angles of incidence (theta

Moeck, Peter

290

Aneta Siemiginowska Chandra X-ray Center  

E-Print Network [OSTI]

-ray and gamma-ray · High Energy Sky · Chandra X-ray Observatory · examples of typical X-ray data, · an example of a data analysis process · statistical challenges · what do we learn from the data? #12;What is Astronomy and phenomena do we study and how? Solar System: Sun and sollar wind, planets, moons, asteroids, comets Our

Wolfe, Patrick J.

291

Watershed in X-ray Astronomy  

Science Journals Connector (OSTI)

... extent the article on page 96 of this issue of Nature from the X-ray astronomy group at the Massachusetts Institute of Technology is a record of disappointments. That is ... near the galactic centre. Now that the first satellite to be devoted to X-ray astronomy has been launched, and is apparently working successfully, the MIT article and another from ...

1971-01-08T23:59:59.000Z

292

X-Ray Identification of Element 104  

Science Journals Connector (OSTI)

The daughter x-ray identification technique has been applied to the identification of element 104. The characteristic K-series x rays from the ?-decay daughter isotope, nobelium (Z=102), have been observed in coincidence with ? particles from the decay of 4.5-sec 104257, thus providing an unequivocal determination of the parent atomic number, Z=104.

C. E. Bemis; Jr.; R. J. Silva; D. C. Hensley; O. L. Keller; Jr.; J. R. Tarrant; L. D. Hunt; P. F. Dittner; R. L. Hahn; C. D. Goodman

1973-09-03T23:59:59.000Z

293

Quantitative Measurements of X-ray Intensity  

SciTech Connect (OSTI)

This chapter describes the characterization of several X-ray sources and their use in calibrating different types of X-ray cameras at National Security Technologies, LLC (NSTec). The cameras are employed in experimental plasma studies at Lawrence Livermore National Laboratory (LLNL), including the National Ignition Facility (NIF). The sources provide X-rays in the energy range from several hundred eV to 110 keV. The key to this effort is measuring the X-ray beam intensity accurately and traceable to international standards. This is accomplished using photodiodes of several types that are calibrated using radioactive sources and a synchrotron source using methods and materials that are traceable to the U.S. National Institute of Standards and Technology (NIST). The accreditation procedures are described. The chapter begins with an introduction to the fundamental concepts of X-ray physics. The types of X-ray sources that are used for device calibration are described. The next section describes the photodiode types that are used for measuring X-ray intensity: power measuring photodiodes, energy dispersive photodiodes, and cameras comprising photodiodes as pixel elements. Following their description, the methods used to calibrate the primary detectors, the power measuring photodiodes and the energy dispersive photodiodes, as well as the method used to get traceability to international standards are described. The X-ray source beams can then be measured using the primary detectors. The final section then describes the use of the calibrated X-ray beams to calibrate X-ray cameras. Many of the references are web sites that provide databases, explanations of the data and how it was generated, and data calculations for specific cases. Several general reference books related to the major topics are included. Papers expanding some subjects are cited.

Haugh, M. J., Schneider, M.

2011-09-01T23:59:59.000Z

294

X-ray Practicals Series 1 Advanced Data Reduction  

E-Print Network [OSTI]

X-ray Practicals Series 1 Advanced Data Reduction Instructor J. Reibenspies, Ph. D. Nattamai Bhuvanesh, Ph.D. Version 1.0.0 #12;X-ray Practicals Series 2 #12;X-ray Practicals Series 3 #12;X-ray is good. The y direction is shifting the most, but the shift is ok #12;X-ray Practicals Series 5 Other

Meagher, Mary

295

Do X-ray Binary Spectral State Transition Luminosities Vary?  

E-Print Network [OSTI]

We tabulate the luminosities of the soft-to-hard state transitions of all X-ray binaries for which there exist good X-ray flux measurements at the time of the transition, good distance estimates, and good mass estimates for the compact star. We show that the state transition luminosities are at about 1-4% of the Eddington rate, markedly smaller than those typically quoted in the literature, with a mean value of 2%. Only the black hole candidate GRO J~1655-40 and the neutron star systems Aql X-1 and 4U 1728-34 have measured state transition luminosities inconsistent with this value at the 1$\\sigma$ level. GRO J~1655-40, in particular, shows a state transition luminosity below the mean value for the other sources at the $4\\sigma$ level. This result, combined with the known inner disk inclination angle (the disk is nearly parallel to the line of sight) from GRO J~1655-40's relativistic jets suggest that the hard X-ray emitting region in GRO J~1655-40 can have a velocity of no more than about $\\beta=0.68$, with a most likely value of about $\\beta=0.52$, and a minimum speed of $\\beta=0.45$, assuming that the variations in state transition luminosities are solely due to relativistic beaming effects. The variance in the state transition luminosities suggests an emission region with a velocity of $\\sim0.2c$. The results are discussed in terms of different emission models for the low/hard state. We also discuss the implications for measuring the dimensionless viscosity parameter $\\alpha$. We also find that if its state transitions occur at typical luminosities, then GX 339-4 is likely to be at a distance of at least 7.6 kpc, much further than typically quoted estimates.

Thomas J. Maccarone

2003-08-02T23:59:59.000Z

296

X-ray sources in globular clusters  

E-Print Network [OSTI]

The twelve bright (Lx>10(36) erg/s) X-ray sources in the globular clusters have lower luminosities than the brightest sources in the bulge of our galaxy. The dim (Lx<10(35) erg/s) X-ray sources in globular clusters reach higher luminosities than the cataclysmic variables in the disk of our galaxy. The first difference is a statistical fluke, as comparison with M31 indicates. The second difference is explained because the brightest of the dim sources are not cataclysmic variables, but soft X-ray transients in quiescence. This article describes the BeppoSAX, ROSAT and first Chandra observations leading to these conclusions.

Frank Verbunt

2001-11-22T23:59:59.000Z

297

X-RAY EMISSION FROM PLANETS AND COMETS: RELATIONSHIP WITH SOLAR X-RAYS AND SOLAR WIND  

E-Print Network [OSTI]

with the occurrence of solar X-ray flare, when light travel time delay is accounted, suggesting that X-rays fromX-RAY EMISSION FROM PLANETS AND COMETS: RELATIONSHIP WITH SOLAR X-RAYS AND SOLAR WIND ANIL BHARDWAJ Flight center, Greenbelt, MD 20771, USA Scattering of solar X-ray radiation mainly produces the non

Ã?stgaard, Nikolai

298

X-Ray Diffraction The X-Ray Diffraction facility is equipped with state-of-the-art  

E-Print Network [OSTI]

X-Ray Diffraction The X-Ray Diffraction facility is equipped with state-of-the-art diffractometers offering both single crystal and powder X-Ray diffraction. Powder X-Ray Diffraction High resolution data For more details on powder X-Ray analysis contact Dr J Hriljac on 0121 414 4458 or email: j

Birmingham, University of

299

Novel X-Ray Imaging Opportunities for the RPI Linear Accelerator's Tunable, Quasi-monochromatic X-ray Source  

E-Print Network [OSTI]

Novel X-Ray Imaging Opportunities for the RPI Linear Accelerator's Tunable, Quasi-monochromatic X-ray of an intense, tunable, polarized, and quasi-monochromatic X-ray source has been ongoing at Rensselaer Polytechnic Institute since 2001 [1, 2, 3, 4, 5, 6]. This X-ray source, known as Parametric X-rays (PXR

Danon, Yaron

300

X-ray Dip Monitoring of XB 1916-053  

E-Print Network [OSTI]

We report on the long term monitoring of X-ray dips from the ultracompact low-mass X-ray binary (LMXB) XB 1916-053. Roughly one-month interval observations were carried out with the Rossi X-ray Timing Explorer (RXTE) during 1996, during which the source varied between dim, hard states and more luminous, soft states. The dip spectra and dip lightcurves were compared against both the broadband luminosity and the derived mass accretion rate Mdot. The dips spectra could be fitted by an absorbed blackbody plus cut-off power law non-dip spectral model, with additional absorption ranging from 0 to >100 x 10^22 cm^-2. The amount of additional blackbody absorption was found to vary with the source luminosity. Our results are consistent with an obscuration of the inner disk region by a partially ionized outer disk. The size of the corona, derived from the dip ingress times, was found to be ~10^9 cm. The corona size did not correlate with the coronal temperature, but seemed to increase when \\Mdot also increased. We discuss our findings in the context of an evaporated accretion disk corona model and an ADAF-type model.

T. Narita; J. E. Grindlay; P. F. Bloser; Y. Chou

2003-05-06T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Size dependence of solar X-ray flare properties  

E-Print Network [OSTI]

Non-thermal and thermal parameters of 85 solar flares of GOES class B1 to M6 (background subtracted classes A1 to M6) have been compared to each other. The hard X-ray flux has been measured by RHESSI and a spectral fitting provided flux and spectral index of the non-thermal emission, as well as temperature and emission measure of the thermal emission. The soft X-ray flux was taken from GOES measurements. We find a linear correlation in a double logarithmic plot between the non-thermal flux and the spectral index. The higher the acceleration rate of a flare, the harder the non-thermal electron distribution. The relation is similar to the one found by a comparison of the same parameters from several sub-peaks of a single flare. Thus small flares behave like small subpeaks of large flares. Thermal flare properties such as temperature, emission measure and the soft X-ray flux also correlate with peak non-thermal flux. A large non-thermal peak flux entails an enhancement in both thermal parameters. The relation between spectral index and the non-thermal flux is an intrinsic feature of the particle acceleration process, depending on flare size. This property affects the reported frequency distribution of flare energies.

Marina Battaglia; Paolo C. Grigis; Arnold O. Benz

2005-05-09T23:59:59.000Z

302

3D View Inside the Skeleton with X-ray Microscopy: Imaging Bone at the  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

3D View Inside the Skeleton with X-ray Microscopy: Imaging Bone 3D View Inside the Skeleton with X-ray Microscopy: Imaging Bone at the Nanoscale Scientists studying osteoporosis and other skeletal diseases are interested in the 3D structure of bone and its responses to conditions such as weightlessness, radiation (of particular interest to astronauts) and vitamin D deficiency. The current gold standard, micro-computed tomography (micro-CT), provides 3D images of trabeculae, the small interior struts of bone tissue, and electron microscopy can provide nanometer resolution of thin tissue slices. Hard X-ray transmission microscopy has provided the first 3D view of bone structure within individual trabeculae on the nanoscale. figure 1 Figure 1 Micro-CT (left) shows trabecular structure inside of bone. Transmission X-ray microscopy (TXM; center and right) can reveal localized details of osteocyte lacunae and their processes.

303

X-ray Absorption Spectroscopy of Biologically Relevant Systems  

E-Print Network [OSTI]

308, Messer, B. M. X-ray Absorption Spectroscopy of AqueousSarcosine via X-ray Absorption Spectroscopy 5.1 Introductionwith Carboxylate by X-Ray Absorption Spectroscopy of Liquid

Uejio, Janel Sunayo

2010-01-01T23:59:59.000Z

304

Compact X-Ray Light Source Workshop | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Compact X-Ray Light Source Workshop Compact X-Ray Light Source Workshop Teller R, Terminello L, Thevuthasan T, Moncton D. 2012. "Compact X-Ray Light Source Workshop Report."...

305

Biological Imaging by Soft X-Ray Diffraction Microscopy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Biological Imaging by Soft X-Ray Diffraction Microscopy Print Wednesday, 30 November 2005 00:00 Electron and x-ray...

306

Rippled beam free electron laser amplifier  

DOE Patents [OSTI]

A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a TM.sub.0n mode. A waveguide defines an axial centerline and, a solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.

Carlsten, Bruce E. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

307

A SOURCE OF COHERENT SOFT X-RAY RADIATION BASED ON HIGH-ORDER HARMONIC GENERATION AND FREE ELECTRON  

E-Print Network [OSTI]

at shorter wavelengths down to 4 nm is obtained by bunching the energy modulated electrons and passing ultraviolet (EUV) (see [1] and references therein). The repetition rate of these pulses depends been demon- strated with a repetition rate of the order of 1 kHz. Higher pulse energies have also been

Wurtele, Jonathan

308

In vivo crystallography at X-ray free-electron lasers: the next generation of structural biology?  

Science Journals Connector (OSTI)

...2-1 Yamadaoka, Suita, Osaka 565-0871, Japan 9 Japan Synchrotron Radiation Research Institute, , Kouto 1-1-1, Sayo...hutch 3 of SACLA with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No...

2014-01-01T23:59:59.000Z

309

Opportunities and challenges for time-resolved studies of protein structural dynamics at X-ray free-electron lasers  

Science Journals Connector (OSTI)

...functional transitions in proteins. Proc. Natl Acad...Woodbury, NW. 2007 Protein dynamics control the...2011 New light on disordered ensembles: ab initio structure...vibrational dynamics of a protein in liquid water by terahertz...

2014-01-01T23:59:59.000Z

310

Multiphoton above-threshold ionization in superintense free-electron x-ray laser fields: Beyond the dipole approximation  

E-Print Network [OSTI]

(k,k?,t)Yl?m?(? ?,??)d#12;d#12;? (17) and Blm,l?m? (k,k?,t) = kk? ? ? Y ?lm(?,?)B(k,k?,t)Yl?m?(? ?,??)d#12;d#12;?, (18) respectively. For the laser pulse given by Eq. (2), Dlm,l?m?(k,k?,t) and Blm,l?m? (k,k?,t) are calculated using Eqs. (B1) and (B2) in Appendix B...†(k?,k,t) = D(k,k?,t) and B†(k?,k,t) = B(k,k?,t). Thus the P-space Hamiltonian given by Eq. (7), H (k,k?,t), is Hermitian. APPENDIX B: P-SPACE PARTIAL-WAVE LASER-ELECTRON INTERACTIONS Substituting Eqs. (A1) and (A2) into Eqs. (17) and (18), respectively, we...

Zhou, Zhongyuan; Chu, Shih-I

2013-02-13T23:59:59.000Z

311

APS Bending Magnet X-rays and  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Irradiation of Nd-Fe-B Permanent Magnets with Irradiation of Nd-Fe-B Permanent Magnets with APS Bending Magnet X-rays and 60 Co γ-rays J. Alderman and P.K. Job APS Operations Division Advanced Photon Source J. Puhl Ionizing Radiation Division National Institute of Standards and Technology June 2000 Table of Contents Introduction Radiation-Induced Demagnetization of Permanent Magnets Resources Required γ-ray Irradiation Results and Analysis of γ-ray Irradiation X-ray Irradiation Results and Analysis of X-ray Irradiation Summary and Conclusions Acknowledgements References Tables and Figures Introduction The Advanced Photon Source (APS), as well as other third-generation synchrotron light sources, uses permanent magnets in the insertion devices to produce x-rays for scientific

312

X-ray source for mammography  

DOE Patents [OSTI]

An x-ray source utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms.

Logan, Clinton M. (Pleasanton, CA)

1994-01-01T23:59:59.000Z

313

Ultrafast X-Ray Sources and Science  

Science Journals Connector (OSTI)

X-ray science is entering the ultrafast and ultraintense era - spurred by developments in coherent, short-wavelength sources that range from tabletop to accelerator-based. These...

Young, Linda

314

X-ray induced optical reflectivity  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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

Durbin, Stephen M.

2012-01-01T23:59:59.000Z

315

SMB, X-ray Emission Spectroscopy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Emission Spectroscopy Beam Line 6-2b X-ray Emission Spectroscopy Beam Line 6-2b is an advanced spectroscopy experimental station on the multidisciplinary general user wiggler Beam...

316

X-raying galaxies: A Chandra legacy  

Science Journals Connector (OSTI)

...Astronomy, University of Massachusetts, Amherst, MA 01003 This presentation...stellar x-ray sources in the solar neighborhood (8). The...elements—Meteoritic and solar . Geochim Cosmochim Acta 53...Astronomy, University of Massachusetts, Amherst, MA 01003, USA...

Q. Daniel Wang

2010-01-01T23:59:59.000Z

317

Small Angle X-Ray Scattering Detector  

DOE Patents [OSTI]

A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.

Hessler, Jan P.

2004-06-15T23:59:59.000Z

318

X-Ray Nanoimaging: Instruments and Methods  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Nanoimaging: Instruments and Methods To be held as part of SPIE. http:spie.orgOP318 August 28-29, 2013; San Diego, California, USA...

319

Femtosecond X-ray protein nanocrystallography  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Femtosecond X-ray protein nanocrystallography Authors: Chapman, H.N., Fromme, P., Barty, A., White, T.A., Kirian, R.A., Aquila, A., Hunter, M.S., Schulz, J., DePonte, D.P.,...

320

X-ray source for mammography  

DOE Patents [OSTI]

An x-ray source is described utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms. 6 figures.

Logan, C.M.

1994-12-20T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Availability Performance and Considerations for LCLS X-Ray FEL at SLAC  

SciTech Connect (OSTI)

The Linac Coherent Light Source (LCLS) is an X-ray Free Electron Laser (FEL) facility located at the SLAC National Accelerator Laboratory. LCLS has been in operation since spring 2009, and it has completed its 3rd user run. LCLS is the first in its class of X-ray FEL user facilities, and presents different availability challenges compared to storage ring light sources. This paper presents recent availability performance of the FEL as well as factors to consider when defining the operational availability figure of merit for user runs. During LCLS [1] user runs, an availability of 95% has been set as a goal. In run III, LCLS photon and electron beam systems achieved availabilities of 94.8% and 96.7%, respectively. The total availability goal can be distributed among subsystems to track performance and identify areas that need attention in order to maintain and improve hardware reliability and operational availability. Careful beam time accounting is needed to understand the distribution of down time. The LCLS complex includes multiple experimental hutches for X-ray science, and each user program has different requirements of a set of parameters that the FEL can be configured to deliver. Since each user may have different criteria for what is considered 'acceptable beam', the quality of the beam must be considered to determine the X-ray beam availability.

Allen, W.B.; Brachmann, A.; Colocho, W.; Stanek, M.; Warren, J.; /SLAC; ,

2011-08-16T23:59:59.000Z

322

THE CORRELATION BETWEEN DISPERSION MEASURE AND X-RAY COLUMN DENSITY FROM RADIO PULSARS  

SciTech Connect (OSTI)

Pulsars are remarkable objects that emit across the entire electromagnetic spectrum, providing a powerful probe of the interstellar medium. In this study, we investigate the relation between dispersion measure (DM) and X-ray absorption column density N{sub H} using 68 radio pulsars detected at X-ray energies with the Chandra X-Ray Observatory or XMM-Newton. We find a best-fit empirical linear relation of N{sub H} (10{sup 20} cm{sup -2})= 0.30{sup +0.13}{sub -0.09} DM (pc cm{sup -3}), which corresponds to an average ionization of 10{sup +4}{sub -3}%, confirming the ratio of one free electron per 10 neutral hydrogen atoms commonly assumed in the literature. We also compare different N{sub H} estimates and note that some N{sub H} values obtained from X-ray observations are higher than the total Galactic H I column density along the same line of sight, while the optical extinction generally gives the best N{sub H} predictions.

He, C.; Ng, C.-Y.; Kaspi, V. M., E-mail: ncy@bohr.physics.hku.hk [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada)

2013-05-01T23:59:59.000Z

323

THREE-DIMENSIONAL IMAGING OF NANOSCALE MATERIALS BY UISNG COHERENT X-RAYS  

SciTech Connect (OSTI)

X-ray crystallography is currently the primary methodology used to determine the 3D structure of materials and macromolecules. However, many nanostructures, disordered materials, biomaterials, hybrid materials and biological specimens are noncrystalline and, hence, their structures are not accessible by X-ray crystallography. Probing these structures therefore requires the employment of different approaches. A very promising technique currently under rapid development is X-ray diffraction microscopy (or lensless imaging), in which the coherent X-ray diffraction pattern of a noncrystalline specimen is measured and then directly phased to obtain a high-resolution image. Through the DOE support over the past three years, we have applied X-ray diffraction microscopy to quantitative imaging of GaN quantum dot particles, and revealed the internal GaN-Ga2O3 core shell structure in three dimensions. By exploiting the abrupt change in the scattering cross-section near electronic resonances, we carried out the first experimental demonstration of resonant X-ray diffraction microscopy for element specific imaging. We performed nondestructive and quantitative imaging of buried Bi structures inside a Si crystal by directly phasing coherent X-ray diffraction patterns acquired below and above the Bi M5 edge. We have also applied X-ray diffraction microscopy to nondestructive imaging of mineral crystals inside biological composite materials - intramuscular fish bone - at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization and proposed a dynamic mechanism to account for the nucleation and growth of mineral crystals in the collagen matrix. In addition, we have also discovered a novel 3D imaging modality, denoted ankylography, which allows for complete 3D structure determination without the necessity of sample titling or scanning. We showed that when the diffraction pattern of a finite object is sampled at a sufficiently fine scale on the Ewald sphere, the 3D structure of the object is determined by the 2D spherical pattern. We confirmed the theoretical analysis by performing 3D numerical reconstructions of a sodium silicate glass structure at 2 Ã? resolution from a 2D spherical diffraction pattern alone. As X-ray free electron lasers are under rapid development worldwide, ankylography may open up a new horizon to obtain the 3D structure of a non-crystalline specimen from a single pulse and allow time-resolved 3D structure determination of disordered materials.

Jianwei Miao

2011-04-18T23:59:59.000Z

324

Using X-Ray Computed Tomography in Pore Structure Characterization...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Using X-Ray Computed Tomography in Pore Structure Characterization for a Berea Sandstone: Resolution Effect. Using X-Ray Computed Tomography in Pore Structure Characterization for...

325

X-Ray Observations of Radio Galaxies  

E-Print Network [OSTI]

We review some of the ways that X-ray observations provide unique information on radio galaxies. Thermal bremsstrahlung X-ray emission provides detailed data on ambient densities and temperatures. These parameters in turn can be used for pressure balance calculations and can demonstrate how the ambient gas affects radio source structure. Additionally, many signatures of the interaction of radio jets and lobes with the hot gas are found in high resolution X-ray maps. Non-thermal X-ray emission from knots and hotspots of radio jets can give us constraints on the relativistic electron population for energies greater that that normally sampled in the radio (in the case of synchrotron emission) or can give us an independent estimate of the average magnetic field strength (if inverse Compton emission is the origin of the X-rays). From recent ROSAT HRI observations of 3C 390.3 and 3C 120, we show evidence that X-ray emission from knots and hotspots appears to be associated with regions of large gradients in the radio surface brightness; i.e. at the location of powerful shocks.

D. E. Harris

1998-04-20T23:59:59.000Z

326

Compton backscattered collimated x-ray source  

DOE Patents [OSTI]

A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

Ruth, R.D.; Huang, Z.

1998-10-20T23:59:59.000Z

327

Compton backscattered collmated X-ray source  

DOE Patents [OSTI]

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Ruth, Ronald D. (Woodside, CA); Huang, Zhirong (Stanford, CA)

2000-01-01T23:59:59.000Z

328

Compton backscattered collimated x-ray source  

DOE Patents [OSTI]

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Ruth, Ronald D. (Woodside, CA); Huang, Zhirong (Stanford, CA)

1998-01-01T23:59:59.000Z

329

Monte Carlo study for optimal conditions in single-shot imaging with femtosecond x-ray laser pulses  

SciTech Connect (OSTI)

Intense x-ray pulses from x-ray free electron lasers (XFELs) enable the unveiling of atomic structure in material and biological specimens via ultrafast single-shot exposures. As the radiation is intense enough to destroy the sample, a new sample must be provided for each x-ray pulse. These single-particle delivery schemes require careful optimization, though systematic study to find such optimal conditions is still lacking. We have investigated two major single-particle delivery methods: particle injection as flying objects and membrane-mount as fixed targets. The optimal experimental parameters were searched for via Monte Carlo simulations to discover that the maximum single-particle hit rate achievable is close to 40%.

Park, Jaehyun; Ishikawa, Tetsuya; Song, Changyong [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan)] [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Joti, Yasumasa [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

2013-12-23T23:59:59.000Z

330

Development of x-ray laminography under an x-ray microscopic condition  

SciTech Connect (OSTI)

An x-ray laminography system under an x-ray microscopic condition was developed to obtain a three-dimensional structure of laterally-extended planar objects which were difficult to observe by x-ray tomography. An x-ray laminography technique was introduced to an x-ray transmission microscope with zone plate optics. Three prototype sample holders were evaluated for x-ray imaging laminography. Layered copper grid sheets were imaged as a laminated sample. Diatomite powder on a silicon nitride membrane was measured to confirm the applicability of this method to non-planar micro-specimens placed on the membrane. The three-dimensional information of diatom shells on the membrane was obtained at a spatial resolution of sub-micron. Images of biological cells on the membrane were also obtained by using a Zernike phase contrast technique.

Hoshino, Masato; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio; Yagi, Naoto [Japan Synchrotron Radiation Research Institute JASRI/SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

2011-07-15T23:59:59.000Z

331

X-ray views of neutron star low-mass X-ray binaries  

E-Print Network [OSTI]

A neutron star low-mass X-ray binary is a binary stellar system with a neutron star and a low-mass companion star rotating around each other. In this system the neutron star accretes mass from the companion, and as this matter falls into the deep potential well of the neutron star, the gravitational potential energy is released primarily in the X-ray wavelengths. Such a source was first discovered in X-rays in 1962, and this discovery formally gave birth to the "X-ray astronomy". In the subsequent decades, our knowledge of these sources has increased enormously by the observations with several X-ray space missions. Here we give a brief overview of our current understanding of the X-ray observational aspects of these systems.

Sudip Bhattacharyya

2010-02-24T23:59:59.000Z

332

Time resolved studies on X-rays and charged particles emission from a low energy plasma focus device  

Science Journals Connector (OSTI)

The time resolved studies on soft X-ray, hard X-ray, electron beam and ion beam emissions from a low energy plasma focus device are carried out simultaneously by employing a photodiode X-ray spectrometer, a scintillator photomultiplier tube, a combination of Faraday cup and Rogowski coil assembly and a biased Faraday cup, respectively. The soft X-ray is seen to be emitted in short multiple pulses corresponding to different pinch stages where as it is a single for hard X-ray, which corresponds to only maximum pinch stage. Similarly, multiple pulses of electron beam is found, which also corresponds to different pinch stages and these pulses are analogous with the soft X-ray pulses. The effective hard X-ray photon energy is estimated by foil absorption technique and found to be around 110 keV, which is consistent with the observed electron beam energy distribution. The simultaneous investigation of the electron and ion beam shows that both are accelerated by the same local field generated during the pinching process. The detailed results of time resolved studies on various radiations are incorporated in this Letter.

N.K. Neog; S.R. Mohanty; T.K. Borthakur

2008-01-01T23:59:59.000Z

333

Is linear response to x-rays suitable for digital dental x-ray imaging systems? —Theoretical and experimental considerations  

Science Journals Connector (OSTI)

The purpose of this study was to consider theoretically and experimentally the suitability of linear response to x-rays for digital dental x-ray imaging systems.

Keiichi Nishikawa PhD; Mamoru Wakoh DDS; PhD; Kinya Kuroyanagi DDS; PhD

2003-06-01T23:59:59.000Z

334

Jefferson Lab's Free-Electron Laser explores promise of carbon...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Webs of nanotubes on collector plates Webs of nanotubes form on collector plates during the collaboration's FEL experiment (image not actual size). Jefferson Lab's Free-Electron...

335

Jefferson Lab's upgraded Free-Electron Laser produces first ligh...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

upgraded Free-Electron Laser produces first light June 18, 2003 Researchers at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility have produced first...

336

Free-Electron Lasers: Present Status and Future Prospects  

E-Print Network [OSTI]

US Department of Energy under contract DE-AC03-76SF00098. LBL-29124 Free-Electron Lasers: Present Status

Kim, K.-J.

2008-01-01T23:59:59.000Z

337

Repeated X-ray Flaring Activity in Sagittarius A*  

E-Print Network [OSTI]

Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms in this supermassive black hole located at the center of our Galaxy. Several X-ray flares with varying durations and spectral features have already been observed from this object. Here we present the results of two long XMM-Newton observations of the Galactic nucleus carried out in 2004, for a total exposure time of nearly 500 ks. During these observations we detected two flares from Sgr A* with peak 2-10 keV luminosities about 40 times (L ~ 9x10^34 erg s?1) above the quiescent luminosity: one on 2004 March 31 and another on 2004 August 31. The first flare lasted about 2.5 ks and the second about 5 ks. The combined fit on the Epic spectra yield photon indeces of about 1.5 and 1.9 for the first and second flare respectively. This hard photon index strongly suggests the presence of an important population of non-thermal electrons during the event and supports the view that the majority of flaring events tend to be hard and not very luminous.

Guillaume Belanger; Andrea Goldwurm; Fulvio Melia; Farah Yusef-Zadeh; Philippe Ferrando; Delphine Porquet; Nicolas Grosso; Robert Warwick

2005-08-19T23:59:59.000Z

338

Hard x-ray nanotomography of amorphous aluminosilicate cements.  

SciTech Connect (OSTI)

Nanotomographic reconstruction of a sample of low-CO{sub 2} 'geopolymer' cement provides the first three-dimensional view of the pore structure of the aluminosilicate geopolymer gel, as well as evidence for direct binding of geopolymer gel onto unreacted fly ash precursor particles. This is central to understanding and optimizing the durability of concretes made using this new class of binder, and demonstrates the value of nanotomography in providing a three-dimensional view of nanoporous inorganic materials.

Provis, J. L.; Rose, V.; Winarski, R. P.; van Deventer, J. S. J. (Advanced Photon Source); ( CNM)

2011-08-01T23:59:59.000Z

339

Improvement of YOHKOH Hard X-Ray Imaging  

Science Journals Connector (OSTI)

......90 step) 1-2 126 840 210 0.5 mm thick tungsten electric discharge 48 (8 el. x 6 PAs*) 0 , 30 , 60 , 90 , 120 , 150...2 -2 2500 cts cm 10000 cts cm Model Source FWHM 24 arc sec Fig. 8. Numerical simulation of MEM imaging with......

Jun Sato; Takeo Kosugi; Kazuo Makishima

1999-02-01T23:59:59.000Z

340

Hard X-ray Fluorescence Measurements of Heteroepitaxial Solid...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). 20% strontium doped lanthanum manganite (LSM-20) was grown on YSZ and NGO (neodymium gallate). The...

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

X-ray Pinhole Camera Measurements  

SciTech Connect (OSTI)

The development of the rod pinch diode [1] has led to high-resolution radiography for dynamic events such as explosive tests. Rod pinch diodes use a small diameter anode rod, which extends through the aperture of a cathode plate. Electrons borne off the aperture surface can self-insulate and pinch onto the tip of the rod, creating an intense, small x-ray source (Primary Pinch). This source has been utilized as the main diagnostic on numerous experiments that include high-value, single-shot events. In such applications there is an emphasis on machine reliability, x-ray reproducibility, and x-ray quality [2]. In tests with the baseline rod pinch diode, we have observed that an additional pinch (Secondary Pinch) occurs at the interface near the anode rod and the rod holder. This suggests that stray electrons exist that are not associated with the Primary Pinch. In this paper we present measurements on both pinches using an x-ray pinhole camera. The camera is placed downstream of the Primary Pinch at an angle of 60° with respect to the diode centerline. This diagnostic will be employed to diagnose x-ray reproducibility and quality. In addition, we will investigate the performance of hybrid diodes relating to the formation of the Primary and Secondary Pinches.

Nelson, D. S. [NSTec; Berninger, M. J. [NSTec; Flores, P. A. [NSTec; Good, D. E. [NSTec; Henderson, D. J. [NSTec; Hogge, K. W. [NSTec; Huber, S. R. [NSTec; Lutz, S. S. [NSTec; Mitchell, S. E. [NSTec; Howe, R. A. [NSTec; Mitton, C. V. [NSTec; Molina, I. [NSTec; Bozman, D. R. [SNL; Cordova, S. R. [SNL; Mitchell, D. R. [SNL; Oliver, B. V. [SNL; Ormond, E. C. [SNL

2013-07-01T23:59:59.000Z

342

X-ray lithography using holographic images  

DOE Patents [OSTI]

Methods for forming X-ray images having 0.25 {micro}m minimum line widths on X-ray sensitive material are presented. A holographic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required. 15 figs.

Howells, M.S.; Jacobsen, C.

1997-03-18T23:59:59.000Z

343

Oscillations During Thermonuclear X-ray Bursts  

E-Print Network [OSTI]

High amplitude, nearly coherent X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries, a long sought goal of X-ray astronomy. Studies carried out over the past year have led to the discovery of burst oscillations in four new sources, bringing to ten the number with confirmed burst oscillations. I review the status of our knowledge of these oscillations and indicate how they can be used to probe the physics of neutron stars. For a few burst oscillation sources it has been proposed that the strongest and most ubiquitous frequency is actually the first overtone of the spin frequency and hence that two nearly antipodal hot spots are present on the neutron star. This inference has important implications for both the physics of thermonuclear burning as well as the mass - radius relation for neutron stars, so its confirmation is crucial. I discuss recent attempts to confirm this hypothesis for 4U 1636-53, the source for which a signal at the putative fundamental (290 Hz) has been claimed.

Tod E. Strohmayer

2001-01-12T23:59:59.000Z

344

X-ray lithography using holographic images  

DOE Patents [OSTI]

Methods for forming X-ray images having 0.25 .mu.m minimum line widths on X-ray sensitive material are presented. A holgraphic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required.

Howells, Malcolm S. (Berkeley, CA); Jacobsen, Chris (Sound Beach, NY)

1997-01-01T23:59:59.000Z

345

Searching for the orbital period of the ultraluminous X-ray source NGC 1313 X-2  

Science Journals Connector (OSTI)

......F. , Pakull M. W., Soria R., Motch C., 2009, in Rodriguez J., Ferrando P., eds, AIP Conf. Ser. Vol. 1126, Simbol-X: Focusing on the Hard X-Ray Universe. Am. Inst. Phys., Melville, p. 201. King A. R. , 2008, MNRAS, 385......

L. Zampieri; D. Impiombato; R. Falomo; F. Grisé; R. Soria

2012-01-11T23:59:59.000Z

346

Generalized regularization techniques with constraints for the analysis of solar bremsstrahlung X-ray spectra  

E-Print Network [OSTI]

Generalized regularization techniques with constraints for the analysis of solar bremsstrahlung X of Physics & Astronomy, The University of Glasgow, G12 8QQ, UK Abstract. Hard X-ray spectra in solar flares provide knowledge of the electron spectrum that results from acceleration and propagation in the solar

Piana, Michele

347

Relativistic distortions in the X-ray spectrum of Cyg X-1  

Science Journals Connector (OSTI)

......thick disc truncates at a few tens of Schwarzschild radii, with the inner region occupied...least 6R g, the last stable orbit in a Schwarzschild metric (Tanaka et al. 1995; Iwasawa...associated with harder X-ray spectra. This mirrors the results from the hard spectra of......

C. Done; P. T. Zycki

1999-05-11T23:59:59.000Z

348

INTEGRAL discovery of unusually long broad-band X-ray activity from the Supergiant Fast X-ray Transient IGR J18483-0311  

E-Print Network [OSTI]

We report on a broad-band X-ray study (0.5-250 keV) of the Supergiant Fast X-ray Transient IGR J18483-0311 using archival INTEGRAL data and a new targeted XMM-Newton observation. Our INTEGRAL investigation discovered for the first time an unusually long X-ray activity (3-60 keV) which continuously lasted for at least 11 days, i.e. a significant fraction (about 60%) of the entire orbital period, and spanned orbital phases corresponding to both periastron and apastron passages. This prolongated X-ray activity is at odds with the much shorter durations marking outbursts from classical SFXTs especially above 20 keV, as such it represents a departure from their nominal behavior and it adds a further extreme characteristic to the already extreme SFXT IGR J18483-0311. Our IBIS/ISGRI high energy investigation (100-250 keV) of archival outbursts activity from the source showed that the recently reported hint of a possible hard X-ray tail is not real and it is likely due to noisy background. The new XMM-Newton targeted...

Sguera, V; Bird, A J; Bazzano, A

2015-01-01T23:59:59.000Z

349

MULTI-WAVELENGTH STUDY OF THE Be/X-RAY BINARY MXB 0656-072  

SciTech Connect (OSTI)

We present and analyze the optical photometric and spectroscopic data of the Be/X-ray binary MXB 0656-072 from 2006 to 2009. A 101.2 day orbital period is found, for the first time, from the present public X-ray data (Swift/BAT and RXTE/ASM). The anti-correlation between the H{alpha} emission and the UBV brightness of MXB 0656-072 during our 2007 observations indicates that a mass ejection event took place in the system. After the mass ejection, a low-density region might develop around the Oe star. With the outward motion of the circumstellar disk, the outer part of the disk interacted with the neutron star around its periastron passage and a series of X-ray outbursts were triggered between MJD 54350 and MJD 54850. The Proportional Counter Array-HEXTE spectra during the 2007-2008 X-ray outbursts could be well fitted by a cutoff power law with low-energy absorption, together with an iron line around 6.4 keV, and a broad cyclotron resonance feature around 30 keV. The same variability of the soft and hard X-ray colors in 2.3-21 keV indicated that there were no overall changes in the spectral shape during the X-ray outbursts, which might only be connected with the changes of the mass accretion rate onto the neutron star.

Yan Jingzhi; Li Hui; Liu Qingzhong [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zurita Heras, Juan Antonio; Chaty, Sylvain, E-mail: jzyan@pmo.ac.cn, E-mail: hli@pmo.ac.cn, E-mail: qzliu@pmo.ac.cn, E-mail: juan-antonio.zurita-heras@cea.fr, E-mail: sylvain.chaty@cea.fr [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, FR-91191 Gif-sur-Yvette (France)

2012-07-01T23:59:59.000Z

350

Predicted X-ray backgrounds for the International X-ray Observatory  

E-Print Network [OSTI]

The background that will be observed by IXO's X-ray detectors naturally separates into two components: (1) a Cosmic X-ray Background (CXB), primarily due to unresolved point sources at high energies (E>2 keV), along with ...

Bautz, Marshall W.

351

Reflection soft X-ray microscope and method  

DOE Patents [OSTI]

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

Suckewer, Szymon (Princeton, NJ); Skinner, Charles H. (Lawrenceville, NJ); Rosser, Roy (Princeton, NJ)

1993-01-01T23:59:59.000Z

352

Differential phase contrast X-ray imaging system and components  

DOE Patents [OSTI]

A differential phase contrast X-ray imaging system includes an X-ray illumination system, a beam splitter arranged in an optical path of the X-ray illumination system, and a detection system arranged in an optical path to detect X-rays after passing through the beam splitter.

Stutman, Daniel; Finkenthal, Michael

2014-07-01T23:59:59.000Z

353

X-ray Studies of Unidentified Galactic TeV Gamma-ray Sources  

SciTech Connect (OSTI)

Many of the recently discovered Galactic TeV sources remain unidentified to date. A large fraction of the sources is possibly associated with relic pulsar wind nebula (PWN) systems. One key question here is the maximum energy (beyond TeV) attained in the compact PWNe. Hard X-ray emission can trace those particles, but current non-focussing X-ray instruments above 10 keV have difficulties to deconvolve the hard pulsar spectrum from its surrounding nebula.Some of the new TeV sources are also expected to originate from middle-aged and possibly even from old supernova remnants (SNR). But no compelling case for such an identification has been found yet. In established young TeV-emitting SNRs, X-ray imaging above 10 keV could help to disentangle the leptonic from the hadronic emission component in the TeV shells, if secondary electrons produced in hadronic collisions can be effectively detected. As SNRs get older, the high energy electron component is expected to fade away. This may allow to verify the picture through X-ray spectral evolution of the source population.Starting from the lessons we have learned so far from X-ray follow-up observations of unidentified TeV sources, prospects for Simbol-X to resolve open questions in this field will be discussed.

Puehlhofer, Gerd [Institut fuer Astronomie und Astrophysik, Sand 1, 72076 Tuebingen (Germany)

2009-05-11T23:59:59.000Z

354

The puzzle of the soft X-ray excess in AGN: absorption or reflection?  

E-Print Network [OSTI]

The 2-10 keV continuum of AGN is generally well represented by a single power law. However, at smaller energies the continuum displays an excess with respect to the extrapolation of this power law, called the ''soft X-ray excess''. Until now this soft X-ray excess was attributed, either to reflection of the hard X-ray source by the accretion disk, or to the presence of an additional comptonizing medium, giving a steep spectrum. An alternative solution proposed by Gierlinski and Done (2004) is that a single power law well represents both the soft and the hard X-ray emission and the impression of the soft X-ray excess is due to absorption of a primary power law by a relativistic wind. We examine the advantages and drawbacks of reflection versus absorption models, and we conclude that the observed spectra can be well modeled, either by absorption (for a strong excess), or by reflection (for a weak excess). However the physical conditions required by the absorption models do not seem very realistic: we would pref...

Chevallier, Loïc; Dumont, A M; Czerny, B; Mouchet, M; Gonçalves, A C; Goosmann, R W

2006-01-01T23:59:59.000Z

355

The puzzle of the soft X-ray excess in AGN: absorption or reflection?  

E-Print Network [OSTI]

The 2-10 keV continuum of AGN is generally well represented by a single power law. However, at smaller energies the continuum displays an excess with respect to the extrapolation of this power law, called the ''soft X-ray excess''. Until now this soft X-ray excess was attributed, either to reflection of the hard X-ray source by the accretion disk, or to the presence of an additional comptonizing medium, giving a steep spectrum. An alternative solution proposed by Gierlinski and Done (2004) is that a single power law well represents both the soft and the hard X-ray emission and the impression of the soft X-ray excess is due to absorption of a primary power law by a relativistic wind. We examine the advantages and drawbacks of reflection versus absorption models, and we conclude that the observed spectra can be well modeled, either by absorption (for a strong excess), or by reflection (for a weak excess). However the physical conditions required by the absorption models do not seem very realistic: we would prefer an ''hybrid model''.

L. Chevallier; S. Collin; A. -M. Dumont; B. Czerny; M. Mouchet; A. C. Goncalves; R. W. Goosmann

2006-01-19T23:59:59.000Z

356

X-ray variability in M87  

E-Print Network [OSTI]

We present the evidence for X-ray variability from the core and from knot A in the M87 jet based on data from two observations with the Einstein Observatory High Resolution Imager (HRI) and three observations with the ROSAT HRI. The core intensity showed a 16% increase in 17 months ('79-'80); a 12% increase in the 3 years '92 to '95; and a 17% drop in the last half of 1995. The intensity of knot A appears to have decreased by 16% between 92Jun and 95Dec. Although the core variability is consistent with general expectations for AGN nuclei, the changes in knot A provide constraints on the x-ray emission process and geometry. Thus we predict that the x-ray morphology of knot A will differ significantly from the radio and optical structure.

D. E. Harris; J. A. Biretta; W. Junor

1996-12-05T23:59:59.000Z

357

Displaced Vertices from X-ray Lines  

E-Print Network [OSTI]

We present a simple model of weak-scale thermal dark matter that gives rise to X-ray lines. Dark matter consists of two nearly degenerate states near the weak scale, which are populated thermally in the early universe via co-annihilation with slightly heavier states that are charged under the Standard Model. The X-ray line arises from the decay of the heavier dark matter component into the lighter one via a radiative dipole transition, at a rate that is slow compared to the age of the universe. The model predicts observable signatures at the LHC in the form of exotic events with missing energy and displaced leptons and jets. As an application, we show how this model can explain the recently observed 3.55 keV X-ray line.

Adam Falkowski; Yonit Hochberg; Joshua T. Ruderman

2014-09-09T23:59:59.000Z

358

A Proof-of-Principle Echo-enabled Harmonic Generation Free Electron Laser Experiment at SLAC  

SciTech Connect (OSTI)

With the advent of X-ray Free Electron Lasers (FELs), new methods have been developed to extend capabilities at short wavelengths beyond Self-Amplified Spontaneous Emission (SASE). In particular, seeding of a FEL allows for temporal control of the radiation pulse and increases the peak brightness by orders of magnitude. Most recently, Gennady Stupakov and colleagues at SLAC proposed a new technique: Echo-Enabled Harmonic Generation (EEHG). Here a laser microbunches the beam in an undulator and the beam is sheared in a chicane. This process is repeated with a second laser, undulator and chicane. The interplay between these allows a seeding of the X-ray laser up to the 100th harmonic of the first laser. After introducing the physics of FELs and the EEHG seeding technique, we describe contributions to the experimental effort. We will present detailed studies of the experiment including the choice of parameters and their optimization, the emittance effect, spontaneous emission in the undulators, the second laser phase effect, and measurements of the jitter between RF stations. Finally, the status and preliminary results of the Echo-7 experiment will be outlined.

Pernet, Pierre-Louis; /Ecole Polytechnique, Lausanne /SLAC

2012-01-06T23:59:59.000Z

359

X-ray focal spot locating apparatus and method  

DOE Patents [OSTI]

An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

Gilbert, Hubert W. (Cedar Crest, NM)

1985-07-30T23:59:59.000Z

360

X-ray Science Division: Groups  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Division: Groups Division: Groups Atomic, Molecular and Optical Physics (AMO) Primary Contact: Stephen Southworth Work focuses on understanding how strong optical and x-ray fields interact with matter, with an emphasis on photonic control of electronic, atomic and molecular motion. Chemical and Materials Science (CMS) Primary Contact: Randy Winans Research Disciplines: Chemistry, Materials Science Detectors (DET) Primary Contact: Antonino Miceli GMCA Structural Biology Facility (MX) Primary Contact: Robert Fischetti Research Disciplines: Biology, Life Sciences Imaging (IMG) Primary Contact: Francesco DeCarlo Research Disciplines: Materials Science, Biology, Physics, Life Sciences Inelastic X-ray & Nuclear Resonant Scattering (IXN) Primary Contact: Thomas Gog Research Disciplines: Condensed Matter Physics, Geophysics, Materials

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Cosmology with X-ray Cluster Baryons  

SciTech Connect (OSTI)

X-ray cluster measurements interpreted with a universal baryon/gas mass fraction can theoretically serve as a cosmological distance probe. We examine issues of cosmological sensitivity for current (e.g., Chandra X-ray Observatory, XMM-Newton) and next generation (e.g., Con-X, XEUS) observations, along with systematic uncertainties and biases. To give competitive next generation constraints on dark energy, we find that systematics will need to be controlled to better than 1percent and any evolution in f_gas (and other cluster gas properties) must be calibrated so the residual uncertainty is weaker than (1+z)0.03.

Linder, Eric V.

2007-04-10T23:59:59.000Z

362

Phase recovery for x-ray crystallography  

Science Journals Connector (OSTI)

For many years people have believed that in conventional x-ray crystallography one can only record the diffraction intensities but not the phases. In order to obtain the atomic arrangements, one usually has to guess a structure and then fit the intensity data by refining its parameters. Here, we show that the phases are in fact hidden in the intensity data, and can be directly recovered from the peak profiles. This method is demonstrated by the normal two-beam x-ray diffraction of a noncentrosymmetric crystal, and nontrivial phases are recovered from the intensity data alone.

G. Xu, G. E. Zhou, and X. Y. Zhang

1999-04-01T23:59:59.000Z

363

Time-resolved x-ray diagnostics  

SciTech Connect (OSTI)

Techniques for time-resolved x-ray diagnostics will be reviewed with emphasis on systems utilizing x-ray diodes or scintillators. System design concerns for high-bandwidth (> 1 GHz) diagnostics will be emphasized. The limitations of a coaxial cable system and a technique for equalizing to improve bandwidth of such a system will be reviewed. Characteristics of new multi-GHz amplifiers will be presented. An example of a complete operational system on the Los Alamos Helios laser will be presented which has a bandwidth near 3 GHz over 38 m of coax. The system includes the cable, an amplifier, an oscilloscope, and a digital camera readout.

Lyons, P.B.

1981-01-01T23:59:59.000Z

364

Optimization of <= 200 um pitch CZT detectors for future high-resolution X-ray instrumentation in astrophysics  

E-Print Network [OSTI]

Cadmium Zinc Telluride and Cadmium Telluride are the detector materials of choice for the detection of X-rays in the X-ray energy band E >= 5keV with excellent spatial and spectral resolution and without cryogenic cooling. Owing to recent breakthroughs in grazing incidence mirror technology, next-generation hard X-ray telescopes will achieve angular resolution between 5 and 10 arc seconds - about an order of magnitude better than that of the NuSTAR hard X-ray telescope. As a consequence, the next generation of X-ray telescopes will require pixelated X-ray detectors with pixels on a grid with a lattice constant of energy threshold of less than 5keV and an energy resolution of less than one keV. The science drivers for a high angular-resolution X-ray mission include studies and measurements of black hole spins, the cosmic evolution of super-massive black holes, active galactic nuclei feedback, and the behaviour of matter at very high densities. In this...

Zajczyk, Anna; Dowkontt, Paul; Guo, Qingzhen; Kislat, Fabian; Krawczynski, Henric; De Geronimo, Gianluigi; Li, Shaorui; Beilicke, Matthias

2015-01-01T23:59:59.000Z

365

Low-Mass X-Ray Binary MAXI J1421-613 Observed by MAXI GSC and Swift XRT  

E-Print Network [OSTI]

Monitor of All sky X-ray Image (MAXI) discovered a new outburst of an X-ray transient source named MAXI J1421-613. Because of the detection of three X-ray bursts from the source, it was identified as a neutron star low-mass X-ray binary. The results of data analyses of the MAXI GSC and the Swift XRT follow-up observations suggest that the spectral hardness remained unchanged during the first two weeks of the outburst. All the XRT spectra in the 0.5-10 keV band can be well explained by thermal Comptonization of multi-color disk blackbody emission. The photon index of the Comptonized component is $\\approx$ 2, which is typical of low-mass X-ray binaries in the low/hard state. Since X-ray bursts have a maximum peak luminosity, it is possible to estimate the (maximum) distance from its observed peak flux. The peak flux of the second X-ray burst, which was observed by the GSC, is about 5 photons cm$^{-2}$ s$^{-1}$. By assuming a blackbody spectrum of 2.5 keV, the maximum distance to the source is estimated as 7 kpc...

Serino, Motoko; Ueda, Yoshihiro; Matsuoka, Masaru; Negoro, Hitoshi; Yamaoka, Kazutaka; Kennea, Jamie A; Fukushima, Kosuke; Nagayama, Takahiro

2015-01-01T23:59:59.000Z

366

The Sun as an X-Ray Star. III. Flares  

Science Journals Connector (OSTI)

In previous works we have developed a method to convert solar X-ray data, collected with the Yohkoh/SXT, into templates of stellar coronal observations. Here we apply the method to several solar flares, for comparison with stellar X-ray flares. Eight flares, from weak (GOES class C5.8) to very intense ones (X9) are selected as representative of the flaring Sun. The emission measure distribution versus temperature, EM(T), of the flaring regions is derived from Yohkoh/SXT observations in the rise, peak, and decay of the flares. The EM(T) is rather peaked and centered around T ? 107 K for most of the time. Typically, it grows during the rise phase of the flare, and then it decreases and shifts toward lower temperatures during the decay, more slowly if there is sustained heating. The most intense flare we studied shows emission measure even at very high temperatures (T ? 108 K). Time-resolved X-ray spectra both unfiltered and filtered through the instrumental responses of the nonsolar instruments ASCA/SIS and ROSAT/PSPC are then derived. Synthesized ASCA/SIS and ROSAT/PSPC spectra are generally well fitted with single thermal components at temperatures close to that of the EM(T) maximum, albeit two thermal components are needed to fit some flare decays. ROSAT/PSPC spectra show that solar flares are in a 2 orders of magnitude flux range (106-108 ergs cm-2 s-1) and a narrow PSPC hardness ratio range, however, higher than that of typical nonflaring solar-like stars.

F. Reale; G. Peres; S. Orlando

2001-01-01T23:59:59.000Z

367

X-ray Phase Imaging Microscopy using a Fresnel Zone Plate and a Transmission Grating  

SciTech Connect (OSTI)

We report on a hard X-ray phase imaging microscopy (a phase-difference microscopy) that consists of an objective and a transmission grating. The simple optical system provides a quantitative phase image, and does not need a wave field mostly coherent on the objective. Our method has a spatial resolution almost same as that of the absorption contrast microscope image obtained by removing the grating. We demonstrate how our approach provides a phase image from experimentally obtained images. Our approach is attractive for easily appending a quantitative phase-sensitive mode to normal X-ray microscopes, and has potentially broad applications in biology and material sciences.

Yashiro, Wataru; Momose, Atsushi [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8561 (Japan); Takeuchi, Akihisa; Suzuki, Yoshio [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198 (Japan)

2010-06-23T23:59:59.000Z

368

Radioactive Thulium for X-Rays  

Science Journals Connector (OSTI)

Radioactive power from thulium makes Argonne x-ray unit a potential for medical and industrial use ... Active component of the instrument is a tiny particle (one-fifth gram) of thulium-170 which has been made radioactive in a heavy water nuclear reactor at Arco, Idaho. ...

1954-05-03T23:59:59.000Z

369

X-ray spectroscopy of manganese clusters  

SciTech Connect (OSTI)

Much of this thesis represents the groundwork necessary in order to probe Mn clusters more productively than with conventional Mn K-edge XAS and is presented in Part 1. Part 2 contains the application of x-ray techniques to Mn metalloproteins and includes a prognosis at the end of each chapter. Individual Mn oxidation states are more readily distinguishable in Mn L-edge spectra. An empirical mixed valence simulation routine for determining the average Mn oxidation state has been developed. The first Mn L-edge spectra of a metalloprotein were measured and interpreted. The energy of Mn K{beta} emission is strongly correlated with average Mn oxidation state. K{beta} results support oxidation states of Mn(III){sub 2}(IV){sub 2} for the S{sub 1} state of Photosystem II chemical chemically reduced preparations contain predominantly Mn(II). A strength and limitation of XAS is that it probes all of the species of a particular element in a sample. It would often be advantageous to selectively probe different forms of the same element. The first demonstration that chemical shifts in x-ray fluorescence energies can be used to obtain oxidation state-selective x-ray absorption spectra is presented. Spin-dependent spectra can also be used to obtain a more simplified picture of local structure. The first spin-polarized extended x-ray absorption fine structure using Mn K{beta} fluorescence detection is shown.

Grush, M.M. [Univ. of California, Davis, CA (United States). Dept. of Applied Science; [Lawrence Berkeley National Lab., CA (United States). Energy and Environment Div.

1996-06-01T23:59:59.000Z

370

Multiple wavelength X-ray monochromators  

DOE Patents [OSTI]

An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focusing the separate first and second output x-ray radiation wavelengths into separate focal points. 3 figs.

Steinmeyer, P.A.

1992-11-17T23:59:59.000Z

371

Soft x-ray laser microscope  

SciTech Connect (OSTI)

The program consisted of two phases (Phase I and Phase II). The goal of the Phase I (first year program) was to design and construct the Soft X-ray Laser Contact Microscope. Such microscope was constructed and adapted to PPL's 18.2nm soft X-ray Laser (SXL), which in turn was modified and prepared for microscopy experiments. Investigation of the photoresist response to 18.2nm laser radiation and transmissivity of 0.1m thick silicion-nitride (Si[sub 3]N[sub 4]) windows were important initial works. The goal of the first year of Phase II was to construct X-ray contact microscope in combination with existing optical phase microscope, already used by biologists. In the second year of Phase II study of dehydrated Horeseshoe Crab and Hela cancer cells were performed with COXRALM. Also during Phase II, the Imaging X-Ray Laser Microscope (IXRALM) was designed and constructed. This paper describes the development of each of the microscopes and their application for research.

Suckewer, P.I.

1990-10-01T23:59:59.000Z

372

Small Angle X-Ray Scattering Detector  

DOE Patents [OSTI]

A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., q.sub.max /q.sub.min.congruent.100.

Hessler, Jan P. (Downers Grove, IL)

2004-06-15T23:59:59.000Z

373

SLAC All Access: X-ray Microscope  

ScienceCinema (OSTI)

SLAC physicists Johanna Nelson and Yijin Liu give a brief overview of the X-ray microscope at the Stanford Synchrotron Radiation Lightsource (SSRL) that is helping improve rechargeable-battery technology by letting researchers peek into the inner workings of batteries as they operate.

Nelson, Johanna; Liu, Yijin

2014-06-13T23:59:59.000Z

374

Laser wakefield generated X-ray probe for femtosecond time-resolved measurements of ionization states of warm dense aluminum  

SciTech Connect (OSTI)

We have developed a laser wakefield generated X-ray probe to directly measure the temporal evolution of the ionization states in warm dense aluminum by means of absorption spectroscopy. As a promising alternative to the free electron excited X-ray sources, Betatron X-ray radiation, with femtosecond pulse duration, provides a new technique to diagnose femtosecond to picosecond transitions in the atomic structure. The X-ray probe system consists of an adjustable Kirkpatrick-Baez (KB) microscope for focusing the Betatron emission to a small probe spot on the sample being measured, and a flat Potassium Acid Phthalate Bragg crystal spectrometer to measure the transmitted X-ray spectrum in the region of the aluminum K-edge absorption lines. An X-ray focal spot size of around 50 ?m was achieved after reflection from the platinum-coated 10-cm-long KB microscope mirrors. Shot to shot positioning stability of the Betatron radiation was measured resulting in an rms shot to shot variation in spatial pointing on the sample of 16 ?m. The entire probe setup had a spectral resolution of ?1.5 eV, a detection bandwidth of ?24 eV, and an overall photon throughput efficiency of the order of 10{sup ?5}. Approximately 10 photons were detected by the X-ray CCD per laser shot within the spectrally resolved detection band. Thus, it is expected that hundreds of shots will be required per absorption spectrum to clearly observe the K-shell absorption features expected from the ionization states of the warm dense aluminum.

Mo, M. Z.; Chen, Z.; Tsui, Y. Y.; Fedosejevs, R. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)] [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada); Fourmaux, S.; Saraf, A.; Otani, K.; Kieffer, J. C. [INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Québec J3X 1S2 (Canada)] [INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Québec J3X 1S2 (Canada); Ng, A. [Department of Physics and Astronomy, University of British Columbia, British Columbia V6T 1Z1 (Canada)] [Department of Physics and Astronomy, University of British Columbia, British Columbia V6T 1Z1 (Canada)

2013-12-15T23:59:59.000Z

375

Two solar flares that became X-ray plasma ejections  

E-Print Network [OSTI]

Solar flares and X-ray plasma ejections (XPEs) occur simultaneously but usually are separated spatially. We present two exceptional events observed by {\\sl Yohkoh} in 2001 October 2 (event 1) and 2000 October 16 (event 2), in which features of flares and XPEs are mixed. Namely, the soft and hard X-ray images show intense sources of emission that move dynamically. Both events occurred inside broad active regions showing complicated multi-level structure reaching up to 200 Mm high. Both events show also similar four-stages evolution: (1) a fast rise of a system of loops, (2) sudden changes in their emission distribution, (3) a reconfiguration leading to liberation of large amounts of plasma, (4) a small, static loop as the final remnant. Nevertheless, the events are probably caused by different physical processes: emerging magnetic flux plus reconnection (event 1) and reconnection plus ballooning instability (event 2). Different is also the final destination of the ejected plasma: in the event 1 overlying magne...

Tomczak, Michal

2013-01-01T23:59:59.000Z

376

Ignition feedback regenerative free electron laser (FEL) amplifier  

DOE Patents [OSTI]

An ignition feedback regenerative amplifier consists of an injector, a linear accelerator with energy recovery, and a high-gain free electron laser amplifier. A fraction of the free electron laser output is coupled to the input to operate the free electron laser in the regenerative mode. A mode filter in this loop prevents run away instability. Another fraction of the output, after suitable frequency up conversion, is used to drive the photocathode. An external laser is provided to start up both the amplifier and the injector, thus igniting the system.

Kim, Kwang-Je (Burr Ridge, IL); Zholents, Alexander (Walnut Creek, CA); Zolotorev, Max (Oakland, CA)

2001-01-01T23:59:59.000Z

377

Synchrotron x-ray fluorescence and extended x-ray absorption fine structure analysis  

SciTech Connect (OSTI)

The advent of dedicated synchrotron radiation sources has led to a significant increase in activity in many areas of science dealing with the interaction of x-rays with matter. Synchrotron radiation provides intense, linearly polarized, naturally collimated, continuously tunable photon beams, which are used to determine not only the elemental composition of a complex, polyatomic, dilute material but also the chemical form of the elements with improved accuracy. Examples of the application of synchrotron radiation include experiments in synchrotron x-ray fluorescence (SXRF) analysis and extended x-ray absorption fine structure (EXAFS) analysis. New synchrotron radiation x-ray microprobes for elemental analysis in the parts per billion range are under construction at several laboratories. 76 references, 24 figures.

Chen, J.R.; Gordon, B.M.; Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Chao, E.C.T.; Minkin, J.A.

1984-01-01T23:59:59.000Z

378

X-ray imaging crystal spectrometer for extended X-ray sources  

DOE Patents [OSTI]

Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokomak fusion experiment to provide spatially and temporally resolved data on plasma parameters using the imaging properties for Bragg angles near 45. For a Bragg angle of 45.degree., the spherical crystal focuses a bundle of near parallel X-rays (the cross section of which is determined by the cross section of the crystal) from the plasma to a point on a detector, with parallel rays inclined to the main plain of diffraction focused to different points on the detector. Thus, it is possible to radially image the plasma X-ray emission in different wavelengths simultaneously with a single crystal.

Bitter, Manfred L. (Princeton, NJ); Fraenkel, Ben (Jerusalem, IL); Gorman, James L. (Bordentown, NJ); Hill, Kenneth W. (Lawrenceville, NJ); Roquemore, A. Lane (Cranbury, NJ); Stodiek, Wolfgang (Princeton, NJ); von Goeler, Schweickhard E. (Princeton, NJ)

2001-01-01T23:59:59.000Z

379

Rise Time Measurement for Ultrafast X-Ray Pulses  

DOE Patents [OSTI]

A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

Celliers, Peter M.; Weber, Franz A.; Moon, Stephen J.

2005-04-05T23:59:59.000Z

380

X-ray microscopy using grazing-incidence reflection optics  

SciTech Connect (OSTI)

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

Price, R.H.

1981-08-06T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

SWIFT J1753.5-0127: a surprising optical/X-ray cross-correlation function  

E-Print Network [OSTI]

We have conducted optical and X-ray simultaneous observations of SWIFT J1753.5-0127 with RXTE and ULTRACAM, while the system persisted in its relatively bright low/hard state. In the cross-correlation function (CCF), we find that the optical leads the X-rays by a few seconds with a broad negative peak, and has a smaller positive peak at positive lags. This is markedly different from what was seen for the similarly interesting system XTE J1118+480, and the first time such a correlation function has been so clearly measured. Furthermore, there appears to be a significant variation of the correlation with X-ray energy. We suggest a physical scenario for its origin.

Martin Durant; Poshak Gandhi; Tariq Shahbaz; Andy Fabian; Jon Miller; V. S. Dhillon; Tom R. Marsh

2008-06-16T23:59:59.000Z

382

Cryogenic x-ray diffraction microscopy utilizing high-pressure cryopreservation  

Science Journals Connector (OSTI)

We present cryo x-ray diffraction microscopy of high-pressure-cryofixed bacteria and report high-convergence imaging with multiple image reconstructions. Hydrated D. radiodurans cells were cryofixed at 200 MPa pressure into ?10??m-thick water layers and their unstained, hydrated cellular environments were imaged by phasing diffraction patterns, reaching sub-30-nm resolutions with hard x-rays. Comparisons were made with conventional ambient-pressure-cryofixed samples, with respect to both coherent small-angle x-ray scattering and the image reconstruction. The results show a correlation between the level of background ice signal and phasing convergence, suggesting that phasing difficulties with frozen-hydrated specimens may be caused by high-background ice scattering.

Enju Lima; Yuriy Chushkin; Peter van der Linden; Chae Un Kim; Federico Zontone; Philippe Carpentier; Sol M. Gruner; Petra Pernot

2014-10-15T23:59:59.000Z

383

In Situ X-Ray Probing Reveals Fingerprints of Surface Platinum Oxide  

SciTech Connect (OSTI)

In situ x-ray absorption spectroscopy (XAS) at the Pt L{sub 3} edge is a useful probe for Pt-O interactions at polymer electrolyte membrane fuel cell (PEMFC) cathodes. We show that XAS using the high energy resolution fluorescence detection (HERFD) mode, applied to a well-defined monolayer Pt/Rh(111) sample where the bulk penetrating hard x-rays probe only surface Pt atoms, provides a unique sensitivity to structure and chemical bonding at the Pt-electrolyte interface. Ab initio multiple-scattering calculations using the FEFF8 code and complementary extended x-ray absorption fine structure (EXAFS) results indicate that the commonly observed large increase of the white-line at high electrochemical potentials on PEMFC cathodes originates from platinum oxide formation, whereas previously proposed chemisorbed oxygen-containing species merely give rise to subtle spectral changes.

Friebel, Daniel

2011-08-24T23:59:59.000Z

384

In situ X-ray Characterization of Energy Storage Materials | Stanford  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-ray Characterization of Energy Storage Materials X-ray Characterization of Energy Storage Materials Tuesday, July 9, 2013 - 11:00am SLAC, Conference Room 137-322 Presented by Johanna Nelson, Stanford Postdoctoral Scholar, SSRL MSD Hard X-ray Department A key factor in the global move towards clean, renewable energy is the electrification of the automobile. Current battery technology limits EV (electric vehicles) to a short travel range, slow recharge, and costly price tag. Li-ion batteries promise the high specific capacity required for EVs to travel 300+ miles on a single charge with a number of possible earth abundant anode and cathode materials; however, set backs such as capacity fading hinder the full capability of these rechargeable batteries. In order to accurately characterize the dynamic electrochemical processes at the

385

RESULTS FROM LONG-TERM OPTICAL MONITORING OF THE SOFT X-RAY TRANSIENT SAX J1810.8-2609  

SciTech Connect (OSTI)

In this paper, we report the long-term optical observation of the faint soft X-ray transient SAX J1810.8-2609 from the Optical Gravitational Lensing Experiment (OGLE) and Microlensing Observations in Astrophysics (MOA). We have focused on the 2007 outburst, and also cross-correlated its optical light curves and quasi-simultaneous X-ray observations from RXTE/Swift. Both the optical and X-ray light curves of the 2007 outburst show multi-peak features. Quasi-simultaneous optical/X-ray luminosity shows that both the X-ray reprocessing and viscously thermal emission can explain the observed optical flux. There is a slight X-ray delay of 0.6 {+-} 0.3 days during the first peak, while the X-ray emission lags the optical emission by {approx}2 days during the rebrightening stage, which suggests that X-ray reprocessing emission contributes significantly to the optical flux in the first peak, but the viscously heated disk origin dominates it during rebrightening. This implies variation of the physical environment of the outer disk, with even the source remaining in a low/hard state during the entire outburst. The {approx}2 day X-ray lag indicates a small accretion disk in the system, and its optical counterpart was not detected by OGLE and MOA during quiescence, which constrained it to be fainter than M{sub I} = 7.5 mag. There is a suspected short-time optical flare detected at MJD = 52583.5 with no detected X-ray counterpart; this single flux increase implies a magnetic loop reconnection in the outer disk, as proposed by Zurita et al. The observations cover all stages of the outburst; however, due to the low sensitivity of RXTE/ASM, we cannot conclude whether it is an optical precursor at the initial rise of the outburst.

Zhu Ling; Di Stefano, Rosanne [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States); Wyrzykowski, Lukasz, E-mail: zhul04@mails.tsinghua.edu.cn [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2012-12-20T23:59:59.000Z

386

Bruker Workshop on Single Crystal X-Ray Diffraction  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Diagnosis and Treatment of Problem Structures: Diagnosis and Treatment of Problem Structures: A Bruker Workshop on Single Crystal X-Ray Diffraction May 30, 2008 Chemistry Department University of Tennessee Knoxville, TN This meeting focuses on the scientific resources of four ORNL user facilities funded by the DOE Office of Basic Energy Sciences. Who Should Attend Synopsis Goals Scheduled Agenda Workshop Materials Confirmed Speakers Important Dates Registration - now open Location - Directions and Map Sponsors Organizing and Local Committee Contacts Relevant Literature, References, Websites Local Information Bruker - UT Workshop Who Should Attend? The Workshop is directed to the newcomer as well as the experienced user of a Bruker Apex / Apex-II system and SHELX software. It will concentrate on hard to solve and/or refine problem structures. We envision it to be

387

Casimir self-energy of a free electron  

E-Print Network [OSTI]

We derive the electromagnetic self-energy and the radiative correction to the gyromagnetic ratio of a free electron using a Casimir energy approach. This method provides an attractive and straightforward physical basis for the renormalization process.

Allan Rosencwaig

2006-06-23T23:59:59.000Z

388

Simulations of the rocketdyne free-electron laser  

SciTech Connect (OSTI)

Rocketdyne is assembling a high-brightness 78 MeV free-electron laser (FEL). In this paper performance calculations using the Rocketdyne FELOPT code are presented for a 1.06 {mu}m system.

Cover, R.A.; Bennett, G.T.; Burke, R.J.; Curtin, M.S.; Lampel, M.C.; Rakowsky, G. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.)

1991-12-01T23:59:59.000Z

389

Tunable, Nanoscale Free-Electron Source of Photons and Plasmons  

Science Journals Connector (OSTI)

The passage of a free-electron beam through a nano-hole in a periodically layered metal/dielectric structure creates a new type of tuneable, nanoscale radiation source, analogous to...

Adamo, G; MacDonald, K F; Zheludev, N I; Fu, Y H; Wang, C -m; Tsai, D P; García de Abajo, F J

390

THE CHANDRA X-RAY SURVEY OF PLANETARY NEBULAE (CHANPLANS): PROBING BINARITY, MAGNETIC FIELDS, AND WIND COLLISIONS  

SciTech Connect (OSTI)

We present an overview of the initial results from the Chandra Planetary Nebula Survey (CHANPLANS), the first systematic (volume-limited) Chandra X-Ray Observatory survey of planetary nebulae (PNe) in the solar neighborhood. The first phase of CHANPLANS targeted 21 mostly high-excitation PNe within {approx}1.5 kpc of Earth, yielding four detections of diffuse X-ray emission and nine detections of X-ray-luminous point sources at the central stars (CSPNe) of these objects. Combining these results with those obtained from Chandra archival data for all (14) other PNe within {approx}1.5 kpc that have been observed to date, we find an overall X-ray detection rate of {approx}70% for the 35 sample objects. Roughly 50% of the PNe observed by Chandra harbor X-ray-luminous CSPNe, while soft, diffuse X-ray emission tracing shocks-in most cases, 'hot bubbles'-formed by energetic wind collisions is detected in {approx}30%; five objects display both diffuse and point-like emission components. The presence (or absence) of X-ray sources appears correlated with PN density structure, in that molecule-poor, elliptical nebulae are more likely to display X-ray emission (either point-like or diffuse) than molecule-rich, bipolar, or Ring-like nebulae. All but one of the point-like CSPNe X-ray sources display X-ray spectra that are harder than expected from hot ({approx}100 kK) central stars emitting as simple blackbodies; the lone apparent exception is the central star of the Dumbbell nebula, NGC 6853. These hard X-ray excesses may suggest a high frequency of binary companions to CSPNe. Other potential explanations include self-shocking winds or PN mass fallback. Most PNe detected as diffuse X-ray sources are elliptical nebulae that display a nested shell/halo structure and bright ansae; the diffuse X-ray emission regions are confined within inner, sharp-rimmed shells. All sample PNe that display diffuse X-ray emission have inner shell dynamical ages {approx}< 5 Multiplication-Sign 10{sup 3} yr, placing firm constraints on the timescale for strong shocks due to wind interactions in PNe. The high-energy emission arising in such wind shocks may contribute to the high excitation states of certain archetypical 'hot bubble' nebulae (e.g., NGC 2392, 3242, 6826, and 7009).

Kastner, J. H.; Montez, R. Jr.; Rapson, V. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA (United States); Frew, D. J.; De Marco, O.; Parker, Q. A. [Department of Physics and Astronomy and Macquarie Research Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia); Miszalski, B. [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Sahai, R. [Jet Propulsion Laboratory, California Institute of Technology, MS 183-900, Pasadena, CA 91109 (United States); Blackman, E.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Chu, Y.-H. [Department of Astronomy, University of Illinois, Champagne-Urbana, IL (United States); Guerrero, M. A. [Instituto de Astrofisica de Astronomia, Glorieta de la Astronomia s/n, Granada 18008 (Spain); Lopez, J. A. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Campus Ensenada, Apdo. Postal 22860, Ensenada, B. C. (Mexico); Zijlstra, A. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Behar, E. [Department of Physics, Technion (Israel); Bujarrabal, V. [Observatorio Astronomico Nacional, Apartado 112, E-28803, Alcala de Henares (Spain); Corradi, R. L. M. [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Nordhaus, J. [Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); Sandin, C., E-mail: jhk@cis.rit.edu, E-mail: soker@physics.technion.ac.il, E-mail: eva.villaver@uam.es [Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); and others

2012-08-15T23:59:59.000Z

391

Effect of anode shape on pinch structure and X-ray emission of plasma focus device  

Science Journals Connector (OSTI)

Abstract The effect of anode shapes on pinch structure and X-ray emission of plasma focus device operated with cylindrical, diverging, oval and converging anode tips is reported. The pinch structure in the radial compression phase has been investigated by employing a triple pinhole camera. It has been observed that pinch structure as well as the X-ray emission of PF device strongly depends upon anode tip designs. For the first time the studies were carried out in two new shapes of anode tips that is the oval and the divergent one. It has been observed that the oval and diverging anode tips are more conducive for the formation of instabilities and hotspot generation. The studies of X-ray emission were also carried out by employing three channels of a p-i-n diode X-ray spectrometer in entire anode designs to corroborate the results of a triple pinhole camera. Additionally, the effective hard X-ray photon energy was also estimated by the radiography method for all the anode tip designs, which indirectly provide a qualitative idea of the generation of induced accelerating field in the pinched column during compression.

N. Talukdar; N.K. Neog; T.K. Borthkur

2013-01-01T23:59:59.000Z

392

Single electron beam rf feedback free electron laser  

DOE Patents [OSTI]

A free electron laser system and electron beam system for a free electron laser which uses rf feedback to enhance efficiency are described. Rf energy is extracted from a single electron beam by decelerating cavities and energy is returned to accelerating cavities using rf returns, such as rf waveguides, rf feedthroughs, resonant feedthroughs, etc. This rf energy is added to rf klystron energy to reduce the required input energy and thereby enhance energy efficiency of the system.

Brau, C.A.; Stein, W.E.; Rockwood, S.D.

1981-02-11T23:59:59.000Z

393

X-rays Illuminate Ancient Archimedes Text  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Related Links: Related Links: May 2005 Headlines TIP Article Press Release Walters Art Museum SSRL Home Page SLAC Home Page Stanford Home Page Tuesday, 31 May 2005 X-rays Illuminate Ancient Archimedes Text (contact: Uwe Bergmann, bergmann@slac.stanford.edu) Archimedes Figure Image provided by Will Noel, The Walters Art Museum An early transcription of Archimedes' mathematical theories has been brought to light through the probing of high-intensity x-rays at SSRL's BL6-2. The text contains part of the Method of Mechanical Theorems, one of Archimedes' most important works, which was probably copied out by a scribe in the tenth century. The parchment on which it was written was later scraped down and reused as pages in a twelfth century prayer book, producing a document known as a palimpsest (which comes from the Greek,

394

HIGH BRILLIANCE X-RAY SCATTERING FOR  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

BRILLIANCE X-RAY SCATTERING FOR BRILLIANCE X-RAY SCATTERING FOR LIFE SCIENCES (LIX) Group Leader: Lin Yang Proposal Team: O. Bilsel 1 , B. Hsiao 2 , H. Huang 3 , T. Irving 4 , A. Menzel 5 , L. Pollack 6 , C. Riekel 7 , J. Rubert 8 , H. Tsuruta 9 , L. Yang 10 1 University of Massachusetts, 2 Stony Brook University, 3 Rice University, 4 IIT, 5SLS, 6 Cornell University, 7 European Synchrotron Radiation Facility, 8 NEU, 9 Stanford Synchrotron Radiation Lightsource, 10 Brookhaven National Laboratory TECHNIQUES AND CAPABILITIES APPLICATIONS ADDITIONAL INFORMATION * Energy range 2-20keV using undulator source. Simultaneous SAXS/WAXS to cover 0.003-3Å -1 at 12keV with 1 micron spot size * Time-resolved solution scattering with resolution of (1) microseconds to milliseconds using continuous-flow mixing (5µm x 10µm spot size) and (2) milliseconds using stopped-

395

Element 104 identified by characteristic x rays  

Science Journals Connector (OSTI)

A research team at the Oak Ridge National Laboratory has recently announced that they have conclusively identified the 257 isotope of element 104. This new work shows promise of shedding light on the controversy between Albert Ghiorso and Georgi N. Flerov the leaders respectively of the groups at Lawrence Berkeley Laboratory and the Joint Institute for Nuclear Research Dubna. The isotope 104 X 257 decays by alpha emission to 102 No 253 with a half?life of 4.3 seconds. The Oak Ridge group observed the K?series x rays from nobelium in coincidence with the alpha particles from 104 X 257 ; the observation of x?ray spectra has never been reported previously by the Berkeley or Dubna workers according to Curtis E. Bemis Jr spokesman for the group.

Ronald J. Cohn

1973-01-01T23:59:59.000Z

396

X-ray radiography for container inspection  

DOE Patents [OSTI]

Arrangements of X-ray inspection systems are described for inspecting high-z materials in voluminous objects such as containers. Inspection methods may involve generating a radiographic image based on detected attenuation corresponding to a pulsed beams of radiation transmitted through a voluminous object. The pulsed beams of radiation are generated by a high-energy source and transmitted substantially downward along an incident angle, of approximately 1.degree. to 30.degree., to a vertical axis extending through the voluminous object. The generated radiographic image may be analyzed to detect on localized high attenuation representative of high-z materials and to discriminate high-z materials from lower and intermediate-z materials on the basis of the high density and greater attenuation of high-z material for higher energy (3-10 MeV) X-rays, and the compact nature of threatening masses of fissionable materials.

Katz, Jonathan I. (Clayton, MO); Morris, Christopher L. (Los Alamos, NM)

2011-06-07T23:59:59.000Z

397

Sample holder for X-ray diffractometry  

DOE Patents [OSTI]

A sample holder for use with X-ray diffractometers with the capability to rotate the sample, as well as to adjust the position of the sample in the x, y, and z directions. Adjustment in the x direction is accomplished through loosening set screws, moving a platform, and retightening the set screws. Motion translators are used for adjustment in the y and z directions. An electric motor rotates the sample, and receives power from the diffractometer.

Hesch, Victor L. (Los Alamos, NM)

1992-01-01T23:59:59.000Z

398

Columbia University X-Ray Measurements  

E-Print Network [OSTI]

V-720 keV · NaI 2x2x2" detector views an energy range of 1 keV-3 MeV Store signal in the tree. computer configuration. Plasmas were created using multi-frequency ECRH, and we find that most of the plasma energy is stored in the fast electrons. The energy spectrum of the x-ray emission below 740 keV is measured

399

Silicon Absolute X-Ray Detectors  

SciTech Connect (OSTI)

The responsivity of silicon photodiodes having no loss in the entrance window, measured using synchrotron radiation in the 1.75 to 60 keV range, was compared to the responsivity calculated using the silicon thickness measured using near-infrared light. The measured and calculated responsivities agree with an average difference of 1.3%. This enables their use as absolute x-ray detectors.

Seely, John F. [Naval Research Laboratory, Washington, D.C. 20375 (United States); Korde, Raj; Sprunck, Jacob [International Radiation Detectors, Inc., Torrance, CA 90505-5243 (United States); Medjoubi, Kadda; Hustache, Stephanie [Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette CEDEX (France)

2010-06-23T23:59:59.000Z

400

Ultrashort x-ray backlighters and applications  

SciTech Connect (OSTI)

Previously, using ultrashort laser pulses focused onto solid targets, we have experimentally studied a controllable ultrafast broadband radiation source in the extreme ultraviolet for time-resolved dynamical studies in ultrafast science [J. Workman, A. Maksimchuk, X. Llu, U. Ellenberger, J. S. Coe, C.-Y. Chien, and D. Umstadter, ``Control of Bright Picosecond X-Ray Emission from Intense Sub- Picosecond Laser-Plasma Interactions,`` Phys. Rev. Lett. 75, 2324 (1995)]. Once armed with a bright ultrafast broadband continuum x-ray source and appropriate detectors, we used the source as a backlighter to study a remotely produced plasma. The application of the source to a problem relevant to high-density matter completes the triad: creating and controlling, efficiently detecting, and applying the source. This work represented the first use of an ultrafast laser- produced x-ray source as a time-resolving probe in an application relevant to atomic, plasma and high-energy-density matter physics. Using the x-ray source as a backlighter, we adopted a pump-probe geometry to investigate the dynamic changes in electronic structure of a thin metallic film as it is perturbed by an ultrashort laser pulse. Because the laser deposits its energy in a skin depth of about 100 {Angstrom} before expansion occurs, up to gigabar pressure shock waves lasting picosecond in duration have been predicted to form in these novel plasmas. This raises the possibility of studying high- energy-density matter relevant to inertial confinement fusion (ICF) and astrophysics in small-scale laboratory experiments. In the past, time-resolved measurements of K-edge shifts in plasmas driven by nanosecond pulses have been used to infer conditions in highly compressed materials. In this study, we used 100-fs laser pulses to impulsively drive shocks into a sample (an untamped 1000 {Angstrom} aluminum film on 2000 {Angstrom} of parylene-n), measuring L-edge shifts.

Umstadter, D., University of Michigan

1997-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

X-ray holography at Lawrence Livermore National Laboratory  

SciTech Connect (OSTI)

The x-ray holography program at the Lawrence Livermore National Laboratory has two principal goals: (1) the development of x-ray diffraction techniques for DNA sequence analysis and (2) the development of x-ray laser holography for structural analysis of intact biological cells and organelles. DNA sequence analysis will be accomplished by applying x-ray diffraction techniques to determine the ensemble average of the sequence of labels along the individual elements of crystalline DNA. X-ray laser holographic imaging will be accomplished by applying three dimensional x-ray holography to elucidate the structure of few hundred angstrom objects such as 300 {Angstrom} chromatin fibers, nuclear pores and nucleic acid replication complexes in living cells. Existing laboratory x-ray lasers will be utilized to produce flash x-ray holograms of the biological structures.

Trebes, J.; Annese, C.; Birdsall, D.; Brase, J.; Gray, J.; Lane, S.; London, R.; Matthews, D.; Peters, D.; Pinkel, D.; Stone, G.; Rapp, D.; Rosen, M.; Weier, U.; Yorkey, T.

1990-10-11T23:59:59.000Z

402

X-Ray Diffraction Microscopy of Magnetic Structures  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing...

403

X-ray diffraction study of zirconia pillared clays  

Science Journals Connector (OSTI)

X-ray powder diffraction (XRPD) and X-ray radial electronic distribution density (RED) of initial and zirconia-pillared interlayered clays (Zr-PILC) were studied. After pillaring, the basal ... under air to 17.7 ...

D.A. Zyuzin; E.M. Moroz; T.G. Kuznetsova…

2004-01-01T23:59:59.000Z

404

Development of a Schwarzschild-type x-ray microscope  

Science Journals Connector (OSTI)

A Schwarzschild-type x-ray microscope has been designed, constructed, and tested. Ni/C multilayers were used as the x-ray mirrors, with a thickness (2d) of 7 nm and 30 layer pairs. The...

Kado, M; Yamashita, K; Ohtani, M; Tanaka, K A; Kodama, R; Kitamoto, S; Yamanaka, T; Nakai, S

1991-01-01T23:59:59.000Z

405

Biological Imaging by Soft X-Ray Diffraction Microscopy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in...

406

A Record Run for the APS X-ray Source  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed A Record Run for the APS X-ray Source FEBRUARY 23, 2012 Bookmark and Share The APS storage ring. X-ray beams and...

407

Resonant Soft X-Ray Scattering - Combining Structural with Spectroscop...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Resonant Soft X-Ray Scattering - Combining Structural with Spectroscopic Refinement Friday, September 28, 2012 - 10:00am SLAC, Bldg. 137, Room 322 SSRL Presents Kevin Stone X-ray...

408

TENDER ENERGY X-RAY ABSORPTION  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

TENDER ENERGY X-RAY ABSORPTION TENDER ENERGY X-RAY ABSORPTION SPECTROSCOPY (TES) Project Team: S. Bare 1,2 , J. Brandes 3 , T. Buonassisi 4 , J. Chen 5,2 , M. Croft 6 , E. DiMasi 7 , A. Frenkel 8,2 , D. Hesterberg 9 , S. Hulbert 7,2 , S. Khalid 7 , S. Myneni 10 , P. Northrup 7,11 , E.T. Rasbury 11 , B. Ravel 12 , R. Reeder 11 , J. Rodriguez 7,2 , D. Sparks 5,13 , V. Stojanoff 7 , G. Waychunas 14 1 UOP LLC, 2 Synchrotron Catalysis Consortium, 3 Skidaway Inst. of Oceanography, 4 MIT Laboratory for Photovoltaics Research, 5 Univ. of Delaware, 6 Rutgers Univ., 7 Brookhaven National Lab, 8 Yeshiva Univ., 9 North Carolina State Univ., 10 Princeton Univ., 11 Stony Brook Univ., 12 NIST, 13 Delaware Environmental Inst., 14 Lawrence Berkeley National Lab TECHNIQUES: High performance and in-situ X-ray absorption spectroscopy and spatially-resolved XAS of

409

The X-ray Telescope of CAST  

E-Print Network [OSTI]

The Cern Axion Solar Telescope (CAST) is in operation and taking data since 2003. The main objective of the CAST experiment is to search for a hypothetical pseudoscalar boson, the axion, which might be produced in the core of the sun. The basic physics process CAST is based on is the time inverted Primakoff effect, by which an axion can be converted into a detectable photon in an external electromagnetic field. The resulting X-ray photons are expected to be thermally distributed between 1 and 7 keV. The most sensitive detector system of CAST is a pn-CCD detector combined with a Wolter I type X-ray mirror system. With the X-ray telescope of CAST a background reduction of more than 2 orders off magnitude is achieved, such that for the first time the axion photon coupling constant g_agg can be probed beyond the best astrophysical constraints g_agg < 1 x 10^-10 GeV^-1.

M. Kuster; H. Bräuninger; S. Cébrian; M. Davenport; C. Elefteriadis; J. Englhauser; H. Fischer; J. Franz; P. Friedrich; R. Hartmann; F. H. Heinsius; D. H. H. Hoffmann; G. Hoffmeister; J. N. Joux; D. Kang; K. Königsmann; R. Kotthaus; T. Papaevangelou; C. Lasseur; A. Lippitsch; G. Lutz; J. Morales; A. Rodríguez; L. Strüder; J. Vogel; K. Zioutas

2007-05-10T23:59:59.000Z

410

Radio-Frequency Beam Conditioner for Fast-Wave Free-Electron Generators of Coherent Radiation  

E-Print Network [OSTI]

for Fast-Wave Free-Electron Generators of Coherent RadiationFAST-WAVE FREE-ELECTRON GENERATORS OF COHERENT RADIATION'OFOR FAST-WAVE FREE-ELECTRON GENERATORS OF COHERENT RADIATION

Sessler, Andrew M.

2008-01-01T23:59:59.000Z

411

Applications of holography to x-ray imaging  

SciTech Connect (OSTI)

In this paper we consider various applications of holographic techniques to the problem of soft x-ray imaging. We give special attention to imaging biological material using x-rays in the wavelength range 24 to 45A. We describe some experiments on formation and reconstruction of x-ray holograms and propose some ways in which holographic techniques might contribute to the difficult problem of fabricating optical elements for use in the soft x-ray region.

Howells, M.; Iarocci, M.; Kenney, J.; Rarback, H.; Rosser, R.; Yun, W.

1985-03-01T23:59:59.000Z

412

Applications of holography to X-ray imaging  

SciTech Connect (OSTI)

In this paper the authors consider various applications of holographic techniques to the problem of soft x-ray imaging. Special attention is given to imaging biological material using x-rays in the wavelength range 24-45A. The authors describe some experiments on formation and reconstruction of x-ray holograms and propose some ways in which holographic techniques might contribute to the difficult problem of fabricating optical elements for use in the soft x-ray region.

Howells, M.; Iarocci, M.; Kenney, J.; Rarback, H.; Rosser, R.; Yun, W.

1985-01-01T23:59:59.000Z

413

X-ray MicroCT Training Presentation  

E-Print Network [OSTI]

X-ray MicroCT Training Presentation T. Fettah Kosar, PhD Center for Nanoscale Systems Harvard) Model: HMXST225 (max. 225 kV) #12;Overview 3 Introduction to X-ray imaging and Computed Tomography (CT) · What are X-rays and how do we generate and image them? · How do we magnify X-ray images and keep them

414

Quantitative x-ray imager (abstract)  

SciTech Connect (OSTI)

We report on development of a quantitative x-ray imager (QXI) for the national Inertial Confinement Fusion Program. Included in this development is a study of photocathode response as a function of photon energy, 2--17.5 keV, which is related to diagnostic development on the National Ignition Facility (NIF). The QXI is defined as being a quantative imager due to the repeated characterization. This instrument is systematically checked out, electronically as well as its photocathode x-ray response, both on a direct current and pulsed x-ray sources, before and after its use on a shot campaign. The QXI is a gated x-ray imager1 used for a variety of experiments conducted in the Inertial Confinement Fusion and Radiation Physics Program. The camera was assembled in Los Alamos and has been under development since 1997 and has now become the workhorse framing camera by the program. The electronics were built by Grant Applied Physics of San Fransisco, CA.2 The QXI has been used at the LANL Trident, LLNL Nova, and University of Rochester Laboratory OMEGA laser facilities. The camera consists of a grated microchannel plate (MCP), a phosphor coated fiberoptic faceplate coupled to film for data readout, along with high speed electronic pulsers to drive the x-ray detector. The QXI has both a two-strip and a four-strip detection head and has the ability to individually bias the gain of each of the strips. The timing of the QXI was done at the Trident short pulse laboratory, using 211 nm light. Single strip jitter was looked at as well and determined to be <25 ps. Flatfielding of the photocathode across the MCP was done with the Trident main laser with 150 J on a gold disk with a 1 ns. Spatial resolution was determined to be <5 {mu}m by using the same laser conditions as before and a backlit 1000 lp/in. grid. The QXI has been used on cylindrical implosion work at the Nova Laser Facility, and on direct-drive cylinder mix and indirect-drive high convergence implosion experiments at OMEGA. Its two-strip module has provided the capability to look at point backlighters, as part of technique development for experiments on the NIF. Its next use will be in March 2000 with its off axis viewer nose at Omega, providing a perpendicular view of Rayleigh--Taylor spike dissipation.

Evans, Scott C.; Archuleta, Tom N.; Oertel, John A.; Walsh, Peter J.

2001-01-01T23:59:59.000Z

415

X-ray Microscopy and Imaging: 2-BM  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

BM BM Introduction The 2-BM beamline offers measurement capabilities for x-ray microtomography, x-ray topography and x-ray microdiffraction. X-ray microtomography and x-ray diffraction instruments are installed on separate optical tables for independent operation with fast switch over time. Optically-coupled high-resolution CCD system is used for microtomography and topography with up to 1 micron spatial resolution. X-ray microdiffraction setup consists of KB microfocussing mirrors (~3 micron minimum spot), four-circle Huber diffractometer, high-precision translation sample stage, two orthogonally-mounted video cameras for viewing sample, fluorescence detector (Si-drift diode) and diffraction detector (a scintillation detector or a CCD). Three different levels of monochromaticity are available. Conventional monochromatic x-rays from a double-bounced Si (111) crystal monochromator (DCM, D E/E=1E-4), wide band-pass monochromatic x-rays from a double multilayer monochromator (DMM, D E/E=1~4E-2) and pink beam. The available x-ray range is from 5 keV to 30 keV. The lower limit is due to the x-ray windows and the upper limit is due to the critical angle of the x-ray mirror. Two different coatings (Cr and Pt) for the x-ray mirror allow either 20 keV or 30 keV energy cutoff.

416

Small Angle X-ray Scattering (SAXS) Laboratory Learning Experiences  

E-Print Network [OSTI]

.A. & Svergun D.I. (1987). Structure Analysis by Small-Angle X-Ray and Neutron Scattering. NY: Plenum PressSmall Angle X-ray Scattering (SAXS) Laboratory Learning Experiences o - Use of small angle X-ray scattering instrumentation o - Programs that you will use SAXS (BRUKER AXS) PRIMUS (Konarev, Volkov, Koch

Meagher, Mary

417

X-ray Diffraction Laboratory Department of Chemistry  

E-Print Network [OSTI]

X-ray Diffraction Laboratory Department of Chemistry Texas A & M University College Station, Texas Phone : 979-845-9125 www.chem.tamu.edu/xray xray@tamu.edu X-rayDiffractionLaboratory DepartmentofChemistry 3255TAMU CollegeStation,TX77843-3255 Mission The purpose of our laboratory is to provide X-ray

Meagher, Mary

418

X-ray Diffraction Practicals 1 Graphics Programs  

E-Print Network [OSTI]

X-ray Diffraction Practicals 1 Graphics Programs that will read SHELX or CIF files J. Reibenspies, N. Bhuvanesh ver 1.0.0 #12;X-ray Diffraction Practicals 2 Free software. Gretep : Reads SHELX files shelx files or output thermal ellipsoid plots. http://www.umass.edu/microbio/rasmol/ #12;X-ray

Meagher, Mary

419

X-ray Emission from Massive Stars David Cohen  

E-Print Network [OSTI]

X-ray Emission from Massive Stars David Cohen Department of Physics and Astronomy Swarthmore University, Oct. 13, 2005 astro.swarthmore.edu/~cohen/ #12;Outline 1. What you need to know: a. X-rays from the Sun - magnetic activity, x-ray spectra b. Hot stars c. Radiation-driven winds and the Doppler shift d

Cohen, David

420

X-Ray Photoelectron Spectroscopy XPS Mark Engelhard  

E-Print Network [OSTI]

X-Ray Photoelectron Spectroscopy XPS Mark Engelhard 1 #12;EMSL XPS Instrumentation 2 Physical Electronics Quantera XPS High Energy Resolution Focused X-ray Beam Capability Catalysis reaction and processing chamber with inert atmosphere glove box connected to a PHI Quantera Scanning X-ray Microprobe

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

X-Ray Interactions with Matter from the Center for X-Ray Optics (CXRO)  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

The primary interactions of low-energy x-rays within condensed matter, viz. photoabsorption and coherent scattering, are described for photon energies outside the absorption threshold regions by using atomic scattering factors. The atomic scattering factors may be accurately determined from the atomic photoabsorption cross sections using modified Kramers-Kronig dispersion relations. From a synthesis of the currently available experimental data and recent theoretical calculations for photoabsorption, the angle-independent, forward-scattering components of the atomic scattering factors have been thus semiempirically determined and tabulated here for 92 elements and for the region 50-30,000 eV. Atomic scattering factors for all angles of coherent scattering and at the higher photon energies are obtained from these tabulated forward-scattering values by adding a simple angle-dependent form-factor correction. The incoherent scattering contributions that become significant for the light elements at the higher photon energies are similarly determined. The basic x-ray interaction relations that are used in applied x-ray physics are presented here in terms of the atomic scattering factors. The bulk optical constants are also related to the atomic scattering factors. These atomic and optical relations are applied to the detailed calculation of the reflectivity characteristics of a series of practical x-ray mirror, multilayer, and crystal monochromators. Comparisons of the results of this semiempirical,"atom-like", description of x-ray interactions for the low-energy region with those of experiment and ab initio theory are presented.

Henke, B.L.; Gullikson, E.M.; Davis, J.C.

422

Calibrating X-ray Imaging Devices for Accurate Intensity Measurement  

SciTech Connect (OSTI)

The purpose of the project presented is to develop methods to accurately calibrate X-ray imaging devices. The approach was to develop X-ray source systems suitable for this endeavor and to develop methods to calibrate solid state detectors to measure source intensity. NSTec X-ray sources used for the absolute calibration of cameras are described, as well as the method of calibrating the source by calibrating the detectors. The work resulted in calibration measurements for several types of X-ray cameras. X-ray camera calibration measured efficiency and efficiency variation over the CCD. Camera types calibrated include: CCD, CID, back thinned (back illuminated), front illuminated.

Haugh, M. J.

2011-07-28T23:59:59.000Z

423

Nonthermal X-ray emission from 3C 273 - The core of a knotty problem  

SciTech Connect (OSTI)

The quasar 3C 273 was observed in the hard X-ray region of the spectrum (15-300 keV) during a stratospheric balloon flight on July 15, 1987. The emitted photon spectrum is well described by a single power law of photon index -1.61 which corresponds to a hard (20-200 keV) X-ray luminosity of 0.8 x 10 to the 47th ergs/s. This flux is consistent with the 1978/1979 HEAO 1 and AIT/MPI measurements and about a factor of three below the high state measured in 1981 (AIT/MPI). The implications of these results with respect to the location of the production site and mechanism are discussed. 26 refs.

Dean, A.J.; Court, A.J.; Dipper, N.A.; Lewis, R.A.; Bazzano, A. (Southampton Univ. (England) CNR, Istituto di Astrofisica Spaziale, Frascati (Italy))

1990-01-01T23:59:59.000Z

424

X-Ray Imaging Crystal Spectrometer for Extended X-Ray Sources  

SciTech Connect (OSTI)

Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokamak fusion experiment to provide spatially and temporally resolved data on plasma parameters such as ion temperature, toroidal and poloidal rotation, electron temperature, impurity ion charge-state distributions, and impurity transport. The imaging properties of these spherically or toroidally curved crystals provide both spectrally and spatially resolved X-ray data from the plasma using only one small spherically or toroidally curved crystal, thus eliminating the requirement for a large array of crystal spectrometers and the need to cross-calibrate the various crystals.

Bitter, Manfred L.; Fraekel, Benjamin; Gorman, James L.; Hill, Kenneth W.; Roquemore, Lane A.; Stodiek, Wolfgang; Goeler, Schweickhard von

1999-05-01T23:59:59.000Z

425

X-Ray Source Based on the Parametric X-Rays  

E-Print Network [OSTI]

Prospects of parametric x-rays (PXR) application for the development of a tuneable quasi-monochromatic x-ray source for medical imaging are discussed. Analysis of basic requirements for electron accelerator shows that it must be relatively low-energy and high-current linac. In comparison with known ultra-relativistic cases, at low energies PXR properties will be modified to a great extent by multiple scattering of the electrons. PXR intensity dependence on target thickness and beam energy are calculated taking multiple scattering into account. It is concluded that PXR source based on real medical accelerators is feasible and can provide x-ray flux needful for obtaining high quality medical images.

Alexander Lobko; Olga Lugovskaya

2005-09-02T23:59:59.000Z

426

Apparatus for monitoring X-ray beam alignment  

DOE Patents [OSTI]

A self-contained, hand-held apparatus is provided for minitoring alignment of an X-ray beam in an instrument employing an X-ray source. The apparatus includes a transducer assembly containing a photoresistor for providing a range of electrical signals responsive to a range of X-ray beam intensities from the X-ray beam being aligned. A circuit, powered by a 7.5 VDC power supply and containing an audio frequency pulse generator whose frequency varies with the resistance of the photoresistor, is provided for generating a range of audible sounds. A portion of the audible range corresponds to low X-ray beam intensity. Another portion of the audible range corresponds to high X-ray beam intensity. The transducer assembly may include an a photoresistor, a thin layer of X-ray fluorescent material, and a filter layer transparent to X-rays but opaque to visible light. X-rays from the beam undergoing alignment penetrate the filter layer and excite the layer of fluorescent material. The light emitted from the fluorescent material alters the resistance of the photoresistor which is in the electrical circuit including the audio pulse generator and a speaker. In employing the apparatus, the X-ray beam is aligned to a complete alignment by adjusting the X-ray beam to produce an audible sound of the maximum frequency.

Steinmeyer, Peter A. (Arvada, CO)

1991-10-08T23:59:59.000Z

427

Introduction to Neutron and X-Ray Scattering  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Scattering Studies of Thin Scattering Studies of Thin Polymer Films Introduction to Neutron and X-Ray Scattering Sunil K. Sinha UCSD/LANL Acknowledgements: Prof. R.Pynn( Indiana U.) Prof. M.Tolan (U. Dortmund) Wilhelm Conrad Röntgen 1845-1923 1895: Discovery of X-Rays 1901 W. C. Röntgen in Physics for the discovery of x-rays. 1914 M. von Laue in Physics for x-ray diffraction from crystals. 1915 W. H. Bragg and W. L. Bragg in Physics for crystal structure determination. 1917 C. G. Barkla in Physics for characteristic radiation of elements. 1924 K. M. G. Siegbahn in Physics for x-ray spectroscopy. 1927 A. H. Compton in Physics for scattering of x-rays by electrons. 1936 P. Debye in Chemistry for diffraction of x-rays and electrons in gases.

428

The constellation X-ray mission  

Science Journals Connector (OSTI)

The Constellation-X mission is a large collecting area X-ray facility emphasizing observations at high spectral resolution (E/?E?300–3000) while covering a broad energy band (0.25–40 keV). This mission will achieve a factor of 100 increased sensitivity over current capabilities and is optimized to observe the effects of extreme gravity close to black holes and test models for the formation of large scale structure in the Universe. It is apart of NASA’s strategic plan for launch towards the end of the first decade of the 21st century.

N. E. White; H. Tananbaum

2001-01-01T23:59:59.000Z

429

X-RAY AND OPTICAL OBSERVATIONS OF A 0535+26  

SciTech Connect (OSTI)

We present recent contemporaneous X-ray and optical observations of the Be/X-ray binary system A 0535+26 with the Fermi/Gamma-ray Burst Monitor (GBM) and several ground-based observatories. These new observations are put into the context of the rich historical data (since {approx}1978) and discussed in terms of the neutron-star-Be-disk interaction. The Be circumstellar disk was exceptionally large just before the 2009 December giant outburst, which may explain the origin of the unusual recent X-ray activity of this source. We found a peculiar evolution of the pulse profile during this giant outburst, with the two main components evolving in opposite ways with energy. A hard 30-70 mHz X-ray quasi-periodic oscillation was detected with GBM during this 2009 December giant outburst. It becomes stronger with increasing energy and disappears at energies below 25 keV. In the long term a strong optical/X-ray correlation was found for this system, however in the medium term the H{alpha} equivalent width and the V-band brightness showed an anti-correlation after {approx}2002 August. Each giant X-ray outburst occurred during a decline phase of the optical brightness, while the H{alpha} showed a strong emission. In late 2010 and before the 2011 February outburst, rapid V/R variations are observed in the strength of the two peaks of the H{alpha} line. These had a period of {approx}25 days and we suggest the presence of a global one-armed oscillation to explain this scenario. A general pattern might be inferred, where the disk becomes weaker and shows V/R variability beginning {approx}6 months following a giant outburst.

Camero-Arranz, A.; Finger, M. H. [Universities Space Research Association, Huntsville, AL 35806 (United States); Wilson-Hodge, C. A.; Jenke, P. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Steele, I. [Liverpool J. Moore's University, Kingsway House, Hatton Garden, Liverpool L3 2AJ (United Kingdom); Coe, M. J.; McBride, V. A. [University of Southampton, University Road, Southampton SO17 1BJ (United Kingdom); Gutierrez-Soto, J. [Instituto de Astrofisica de Andalucia, Glorieta de la Astronomia, s/n, E-18008, Granada (Spain); Kretschmar, P. [ESA/ESAC, Madrid (Spain); Caballero, I.; Rodriguez, J. [AIM-CEA Saclay, Paris (France); Yan, J. [Purple Mountain Observatory, Chinese Academy of Sciences, Beijing (China); Suso, J. [University of Valencia, Poligono de la Coma, s/n, 46980 Paterna (Spain); Case, G.; Cherry, M. L. [Louisiana State University, Boton Rouge, LA 70803 (United States); Guiriec, S. [NASA GSFC, Greenbelt, MD 20771 (United States)

2012-07-20T23:59:59.000Z

430

Renewed activity from the X-ray transient SAXJ 1810.8-2609 with INTEGRAL  

E-Print Network [OSTI]

We report on the results of INTEGRAL observations of the neutron star low mass X-ray binary SAX J1810.8-2609 during its latest active phase in August 2007. The current outburst is the first one since 1998 and the derived luminosity is 1.1-2.6x10^36 erg s-1 in the 20-100 keV energy range. This low outburst luminosity and the long-term time-average accretion rate of ~5x10^-12Msolar/yr suggest that SAXJ 1810.8-2609 is a faint soft X-ray transient. During the flux increase, spectra are consistent with a thermal Comptonization model with a temperature plasma of ~23-30 keV and an optical depth of ~1.2-1.5, independent from luminosity of the system. This is a typical low hard spectral state for which the X-ray emission is attributed to the upscattering of soft seed photons by a hot, optically thin electron plasma. During the decay, spectra have a different shape, the high energy tail being compatible with a single power law. This confirm similar behavior observed by BeppoSAX during the previous outburst, with absence of visible cutoff in the hard X-ray spectrum. INTEGRAL/JEM-X instrument observed four X-ray bursts in Fall 2007. The first one has the highest peak flux (~3.5Crab in 3--25 keV) giving an upper limit to the distance of the source of about 5.7 kpc, for a LEdd~3.8x10^38 erg s^-1. The observed recurrence time of ~1.2 days and the ratio of the total energy emitted in the persistent flux to that emitted in the bursts (~73) allow us to conclude that the burst fuel was composed by mixed hydrogen and helium with X>0.4.

M. Fiocchi; L. Natalucci; J. Chenevez; A. Bazzano; A. Tarana; P. Ubertini; S. Brandt; V. Beckmann; M. Federici; R. Galis; R. Hudec

2008-11-07T23:59:59.000Z

431

RYLLA. [X-ray transport code  

SciTech Connect (OSTI)

This paper describes a computer code, RYLLA, which models the deposition of x-rays into thin metal slabs, and transports the resulting photoelectrons, finding the distribution of electrons leaving the slab from both the front and back surfaces. The slab must be homogeneous, but can contain a mixture of up to 5 different elements. Due to the short electron mean free path at low electron energies, RYLLA should be used only for studying thin slabs, roughly < 100 mg/cm/sup 2/ for low Z metals, and < 10 mg/cm/sup 2/ for high Z metals. X-ray energies should be in the range of 1 to 150 keV, as they are deposited only via photoionization and Compton scattering processes. Following photoionization, a hole exists in the electron cloud of the absorbing atom. This fills either by Auger or fluoresence, resulting in lower energy holes which are also filled. Fluoresence photons are transported and absorbed in the same manner as the primary photons, except that they are isotropically produced. Once all photons have been transported and absorbed, and all holes have been filled, a space- and energy-dependent electron source spectrum has been obtained. This is used in a discrete ordinate expansion solution of the 1-D transport equation, which gives the output electron spectra at the two slab surfaces. This paper discusses both the physics and coding of RYLLA. Examples of user input are given, as are some comparisons with other codes.

Hyde, R.A.

1983-06-08T23:59:59.000Z

432

X-Ray Diffraction on NIF  

SciTech Connect (OSTI)

The National Ignition Facility (NIF) is currently a 192 beam, 1.6 MJ laser. NIF Ramp-Compression Experiments have already made the relevant exo-planet pressure range from 1 to 50 Mbar accessible. We Proposed to Study Carbon Phases by X-Ray Diffraction on NIF. Just a few years ago, ultra-high pressure phase diagrams for materials were very 'simple'. New experiments and theories point out surprising and decidedly complex behavior at the highest pressures considered. High pressures phases of aluminum are also predicted to be complex. Recent metadynamics survey of carbon proposed a dynamic pathway among multiple phases. We need to develop diagnostics and techniques to explore this new regime of highly compressed matter science. X-Ray Diffraction - Understand the phase diagram/EOS/strength/texture of materials to 10's of Mbar. Strategy and physics goals: (1) Powder diffraction; (2) Begin with diamond; (3) Continue with metals etc.; (4) Explore phase diagrams; (5) Develop liquid diffraction; and (6) Reduce background/improve resolution.

Eggert, J H; Wark, J

2012-02-15T23:59:59.000Z

433

Part 2: Coherent emission from Free Electron Lasers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

0 0 Electron beam-based sources of ultrashort x-ray pulses Alexander Zholents Advanced Photon Source, Argonne National Laborator , Argonne, IL 60439 (September 7, 2010) To be published by World Scientific Publishing Co. in Reviews of Accelerator Science and Technology. y 2 Electron beam-based sources of ultrashort x-ray pulses * Alexander Zholents Argonne National Laboratory, Advanced Photon Source, 9700 South Cass Ave., Argonne, IL 60439 Abstract A review of various methods for generation of ultrashort x-ray pulses using relativistic electron beam from conventional accelerators is presented. Both spontaneous and coherent emission of electrons is considered. Introduction The importance of the time-resolved studies of matter at picosecond (ps),

434

Development of procedures for refurbishing x-ray optics at the Advanced Light Source  

E-Print Network [OSTI]

Development of procedures for refurbishing x-ray optics atpractical and robust procedures for refurbishing x-ray

Yashchuk, Valeriy V.

2013-01-01T23:59:59.000Z

435

CHANDRA X-RAY OBSERVATIONS OF 12 MILLISECOND PULSARS IN THE GLOBULAR CLUSTER M28  

SciTech Connect (OSTI)

We present a Chandra X-ray Observatory investigation of the millisecond pulsars in the globular cluster M28 (NGC 6626). In what is one of the deepest X-ray observations of a globular cluster, we firmly detect seven and possibly detect two of the 12 known M28 pulsars. With the exception of PSRs B1821-24 and J1824-2452H, the detected pulsars have relatively soft spectra, with X-ray luminosities 10{sup 30}-10{sup 31} erg s{sup -1} (0.3-8 keV), similar to most 'recycled' pulsars in 47 Tucanae and the field of the Galaxy, implying thermal emission from the pulsar magnetic polar caps. We present the most detailed X-ray spectrum to date of the energetic PSR B1821-24. It is well described by a purely non-thermal spectrum with spectral photon index {Gamma} = 1.23 and luminosity 1.4 x 10{sup 33}{Theta}(D/5.5 kpc){sup 2} erg s{sup -1} (0.3-8 keV), where {Theta} is the fraction of the sky covered by the X-ray emission beam(s). We find no evidence for the previously reported line emission feature around 3.3 keV, most likely as a consequence of improvements in instrument calibration. The X-ray spectrum and pulse profile of PSR B1821-24 suggest that the bulk of unpulsed emission from this pulsar is not of thermal origin, and is likely due to low-level non-thermal magnetospheric radiation, an unresolved pulsar wind nebula, and/or small-angle scattering of the pulsed X-rays by interstellar dust grains. The peculiar binary PSR J1824-2452H shows a relatively hard X-ray spectrum and possible variability at the binary period, indicative of an intrabinary shock formed by interaction between the relativistic pulsar wind and matter from its non-degenerate companion star.

Bogdanov, Slavko [Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Van den Berg, Maureen; Servillat, Mathieu; Grindlay, Jonathan E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Heinke, Craig O. [Department of Physics, University of Alberta, 11322 89 Avenue, Edmonton, AB T6G 2G7 (Canada); Stairs, Ingrid H.; Begin, Steve [Department of Physics, University of British Columbia, 6224 Agricultural Road Vancouver, BC V6T 1Z1 (Canada); Ransom, Scott M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22901 (United States); Freire, Paulo C. C. [Max-Planck-Institut fuer Radio Astronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Becker, Werner, E-mail: bogdanov@physics.mcgill.ca [Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching bei Muenchen (Germany)

2011-04-01T23:59:59.000Z

436

X-ray observations of the Large Magellanic Cloud pulsar PSR B0540-69 and its pulsar wind nebula  

Science Journals Connector (OSTI)

......INTEGRAL pointings will increase the statistics of the total emission, while the advent of hard X-ray focusing telescopes, like Simbol-X (Ferrando et al. 2005), will help to disentangle the pulsed emission from the nebular one also in the HEXTE and IBIS......

R. Campana; T. Mineo; A. De Rosa; E. Massaro; A. J. Dean; L. Bassani

2008-09-11T23:59:59.000Z

437

Soft X-ray properties of "narrow-line" Seyfert 1 galaxies  

E-Print Network [OSTI]

We report on AGN with extremely soft X-ray spectra observed with ROSAT. From their optical emission lines these objects are classified as narrow-line Seyfert 1 galaxies (NLS1), almost all with extremely large Fe II/H-beta ratios and relatively narrow optical lines of hydrogen. Our results are based on a systematic study of 46 NLS1. We find that NLS1 have generally steeper soft X-ray continuum slopes than normal Seyfert 1s, and there may exist an anticorrelation between 0.1-2.4 keV continuum slope and the FWHM of the H-beta line. Objects with steep 0.1-2.4 keV continuum slopes and H-beta FWHM > 3000 km s^{-1} are clearly discriminated against by nature. When simple power-law models are fit to the data, photon indices reach values up to about 5, much higher than is usually seen in Seyfert 1s. We discuss steep ROSAT spectra in light of soft X-ray excess and hard X-ray tail models. We consider models for NLS1 where they are Seyfert 1s with extremal values of pole-on orientation, black hole mass and/or accretion rate, warm absorption and BLR thickness and confront these models with the known properties of NLS1. All simple models appear to have drawbacks, but models with smaller mass black holes and thicker BLRs show some promise. We suggest specific further tests of the models.

Th. Boller; W. N. Brandt; H. Fink

1995-04-26T23:59:59.000Z

438

KOTOBUKI-1 apparatus for cryogenic coherent X-ray diffraction imaging  

SciTech Connect (OSTI)

We have developed an experimental apparatus named KOTOBUKI-1 for use in coherent X-ray diffraction imaging experiments of frozen-hydrated non-crystalline particles at cryogenic temperature. For cryogenic specimen stage with small positional fluctuation for a long exposure time of more than several minutes, we here use a cryogenic pot cooled by the evaporation cooling effect for liquid nitrogen. In addition, a loading device is developed to bring specimens stored in liquid nitrogen to the specimen stage in vacuum. The apparatus allows diffraction data collection for frozen-hydrated specimens at 66 K with a positional fluctuation of less than 0.4 ?m and provides an experimental environment to easily exchange specimens from liquid nitrogen storage to the specimen stage. The apparatus was developed and utilized in diffraction data collection of non-crystalline particles with dimensions of ?m from material and biological sciences, such as metal colloid particles and chloroplast, at BL29XU of SPring-8. Recently, it has been applied for single-shot diffraction data collection of non-crystalline particles with dimensions of sub-?m using X-ray free electron laser at BL3 of SACLA.

Nakasako, Masayoshi; Takayama, Yuki; Oroguchi, Tomotaka; Sekiguchi, Yuki; Kobayashi, Amane [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan) [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Shirahama, Keiya [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)] [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Yamamoto, Masaki; Hikima, Takaaki; Yonekura, Koji; Maki-Yonekura, Saori; Kohmura, Yoshiki; Inubushi, Yuichi [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan)] [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Takahashi, Yukio; Suzuki, Akihiro [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan) [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Matsunaga, Sachihiro; Inui, Yayoi [Department of Applied Biological Science Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan)] [Department of Applied Biological Science Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Tono, Kensuke; Kameshima, Takashi; Joti, Yasumasa [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Hoshi, Takahiko [Kohzu Precision Co., Ltd., 2-6-15 Kurigi, Aso-ku, Kawasaki, Kanagawa 215-8521 (Japan)] [Kohzu Precision Co., Ltd., 2-6-15 Kurigi, Aso-ku, Kawasaki, Kanagawa 215-8521 (Japan)

2013-09-15T23:59:59.000Z

439

Beam energy distribution influences on density modulation efficiency in seeded free-electron lasers  

E-Print Network [OSTI]

The beam energy spread at the entrance of undulator system is of paramount importance for efficient density modulation in high-gain seeded free-electron lasers (FELs). In this paper, the dependences of high harmonic micro-bunching in the high-gain harmonic generation (HGHG), echo-enabled harmonic generation (EEHG) and phase-merging enhanced harmonic generation (PEHG) schemes on the electron energy spread distribution are studied. Theoretical investigations and multi-dimensional numerical simulations are applied to the cases of uniform and saddle beam energy distributions and compared to a traditional Gaussian distribution. It shows that the uniform and saddle electron energy distributions significantly enhance the performance of HGHG-FELs, while they almost have no influence on EEHG and PEHG schemes. A numerical example demonstrates that, with about 84keV RMS uniform and/or saddle slice energy spread, the 30th harmonic radiation can be directly generated by a single-stage seeding scheme for a soft x-ray FEL f...

Wang, Guanglei; Deng, Haixiao; Zhang, Weiqing; Wu, Guorong; Dai, Dongxu; Wang, Dong; Zhao, Zhentang; Yang, Xueming

2015-01-01T23:59:59.000Z

440

XTREME OPTICS: the behavior of cavity optics for the Jefferson Lab free-electron laser  

SciTech Connect (OSTI)

The cavity optics within high power free-electron lasers based on energy-recovering accelerators are subjected to extreme conditions associated with illumination from a broad spectrum of radiation, often at high irradiances. This is especially true for the output coupler, where absorption of radiation by both the mirror substrate and coating places significant design restrictions to properly manage heat load and prevent mirror distortion. Besides the fundamental lasing wavelength, the mirrors are irradiated with light at harmonics of the fundamental, THz radiation generated by the bending magnets downstream of the wiggler, and x-rays produced when the electron beam strikes accelerator diagnostic components (e.g., wire scanners and view screens) or from inadvertent beam loss. The optics must reside within high vacuum at ~ 10-8 Torr and this requirement introduces its own set of complications. This talk discusses the performance of numerous high reflector and output coupler optics assemblies and provides a detailed list of lessons learned gleaned from years of experience operating the Upgrade IR FEL, a 10 kW-class, sub-ps laser with output wavelength from 1 to 6 microns.

Michelle D. Shinn; Christopher Behre; Stephen Benson; David Douglas; Fred Dylla; Christopher Gould; Joseph Gubeli; David Hardy; Kevin Jordan; George Neil; and Shukui Zhanga

2006-09-25T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Free electron laser amplifier driven by an induction linac  

SciTech Connect (OSTI)

This paper discusses the use of a free-electron laser amplifier as a means of converting the kinetic energy of an electron beam into coherent radiation. In particular, the use of an induction linear accelerator is discussed. The motion of the elections in the tapered and untapered wiggler magnets is discussed as well as the beam emittance, and the radiation fields involved. (LSP)

Neil, V.K.

1986-06-03T23:59:59.000Z

442

Wiggler plane focusing in a linear free electron laser  

DOE Patents [OSTI]

This disclosure describes a free electron laser apparatus that provides a magnetic centering force to turn or focus a non-axial electron toward the longitudinal axis as desired. The focusing effect is provided by wiggler magnet pole faces that are approximately parabolically shaped.

Scharlemann, E.T.

1985-11-21T23:59:59.000Z

443

Free-electron induced chemistry Theoretical Chemistry Section, BARC, Mumbai  

E-Print Network [OSTI]

initiated after the resonant capture low energy free-electrons into considerable interest for various fields reactions is the electronic potential energy surface of the electron compound. In the first half of the talk, I shall present the quantum chemical methodologies for computing the potential energy surfaces

Shyamasundar, R.K.

444

Two-dimensional optimization of free-electron-laser designs  

DOE Patents [OSTI]

Off-axis, two-dimensional designs for free electron lasers are described that maintain correspondence of a light beam with a synchronous electron at an optimal transverse radius r > 0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

Prosnitz, D.; Haas, R.A.

1982-05-04T23:59:59.000Z

445

Two-dimensional optimization of free electron laser designs  

DOE Patents [OSTI]

Off-axis, two-dimensional designs for free electron lasers that maintain correspondence of a light beam with a "synchronous electron" at an optimal transverse radius r>0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

Prosnitz, Donald (Walnut Creek, CA); Haas, Roger A. (Pleasanton, CA)

1985-01-01T23:59:59.000Z

446

Photon Sciences | Beamlines | IXS: Inelastic X-ray Scattering  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

IXS: Inelastic X-ray Scattering IXS: Inelastic X-ray Scattering Poster | Fact Sheet | Preliminary Design Report Scientific Scope Many hot topics related to the high frequency dynamics of condensed matter require both a narrower and steeper resolution function and access to a broader dynamic range than what are currently available. This represents a sort of "no man's land" that falls right in the dynamic gap lying between the high frequency spectroscopies, such as inelastic x-ray scattering (IXS), and the low frequency ones. New IXS spectrometers with improved energy and momentum resolutions would be required to fill this gap. To achieve this goal, a new x-ray optics concept for both the monochromatization and energy analysis of x-rays will be implemented at the NSLS-II Inelastic X-ray Scattering beamline. This solution exploits the

447

X-Ray Fluorescence (XRF) | Open Energy Information  

Open Energy Info (EERE)

X-Ray Fluorescence (XRF) X-Ray Fluorescence (XRF) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: X-Ray Fluorescence (XRF) Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Bulk and trace element analysis of rocks, minerals, and sediments. Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png X-Ray Fluorescence (XRF): X-Ray Fluorescence is a lab-based technique used for bulk chemical analysis of rock, mineral, sediment, and fluid samples. The technique depends on the fundamental principles of x-ray interactions with solid materials, similar

448

X-Ray Diffraction Microscopy of Magnetic Structures  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

449

Biological Imaging by Soft X-Ray Diffraction Microscopy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

450

APS 7-BM Beamline: X-Ray Resources  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Useful Websites Useful Websites X-Ray Interactions with Matter from CRXO at LBNL. Intuitive interface for x-ray transmission and reflectivity for a wide range of materials. X-Ray Data Booklet from LBNL. Slightly outdated in places, but many useful tables of edge energies, fluorescence lines, and crystal lattice spacings. NIST XCOM Database. Powerful database of photoelectric absorption, elastic scattering, and Compton scattering cross-sections for a wide range of materials. X-Ray Server. Maintained by Sergey Stepanov at GMCA at the APS, this website has several powerful calculators for simulating x-ray reflection and diffraction. Software X-Ray Oriented Programs (XOP). This program, written by scientists at the ESRF and APS, is widely used in the synchrotron research community.

451

Biological Imaging by Soft X-Ray Diffraction Microscopy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

452

X-Ray Diffraction Microscopy of Magnetic Structures  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

453

Biological Imaging by Soft X-Ray Diffraction Microscopy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

454

Definition: X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) Jump to: navigation, search Dictionary.png X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) is a laboratory-based technique commonly used for identification of crystalline materials and analysis of unit cell dimensions. One of two primary types of XRD analysis (X-ray powder diffraction and single-crystal XRD) is commonly applied to samples to obtain specific information about the crystalline material under investigation. X-ray powder diffraction is widely used in geology, environmental science, material science, and engineering to rapidly identify unknown crystalline substances (typically in less than 20 minutes). A pure, finely ground, and homogenized sample is required for determination of the bulk composition. Additional uses include detailed

455

X-Ray Diffraction Microscopy of Magnetic Structures  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

456

X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: X-Ray Diffraction (XRD) Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Rapid and unambiguous identification of unknown minerals.[1] Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png X-Ray Diffraction (XRD): X-Ray Diffraction (XRD) is a laboratory-based technique commonly used for identification of crystalline materials and analysis of unit cell dimensions. One of two primary types of XRD analysis (X-ray powder diffraction and single-crystal XRD) is commonly applied to samples to

457

Formation of microbeam using tabletop soft X-ray laser  

Science Journals Connector (OSTI)

An X-ray microprobe with a sub-micron size beam and high intensity can provide X-ray analyses with a remarkable spatial resolution. We have performed focusing of an X-ray laser output into a sub-micron beam for the first time. In our experiment, an X-ray laser of Li-like Al 3d–4f transition at 15.47 nm was delivered from an unstable cavity consisting of a concave mirror and a flat mirror with a square orifice of 100×100 ?m in size. The beam from the orifice was then focused by using a Schwarzschild mirror coated with a Mo/Si multilayer. An X-ray beam size with a diameter of about 0.45 ?m and an estimated photon number of about 2×106 photons per shot was achieved. Such sources could be well suited for the realization of X-ray microprobes.

Tadayuki Ohchi; Naohiro Yamaguchi; Chiemi Fujikawa; Tamio Hara

1999-01-01T23:59:59.000Z

458

Portable X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

Portable X-Ray Diffraction (XRD) Portable X-Ray Diffraction (XRD) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Portable X-Ray Diffraction (XRD) Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Data Collection and Mapping Parent Exploration Technique: Data Collection and Mapping Information Provided by Technique Lithology: Rapid and unambiguous identification of unknown minerals.[1] Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Portable X-Ray Diffraction (XRD): Portable X-Ray Diffraction (XRD) is a field-based technique that can be used for identification of crystalline materials and analysis of unit cell dimensions. Portable XRD analysis is similar to X-ray powder diffraction,

459

Biological Imaging by Soft X-Ray Diffraction Microscopy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

460

X-ray Pinhole Camera Measurements  

SciTech Connect (OSTI)

The rod pinch diode is made up of a cathode plate and a small diameter anode rod that extends through the cathode hole. The anode is charged positively. The rod tip is made of a high-z material which is chosen for its bremsstrahlung efficiency. When the diode is pulsed it produces an intense x-ray source used for pulsed radiography. The baseline or reference diode consists of a 0.75 mm diameter Tungsten (W) tapered anode rod which extends 10 mm through a 9 mm diameter 3 mm thick aluminum (Al) aperture. The majority of the current in the electron beam is created on the edges of the cathode aperture and when properly configured, the electrons will self insulate, travel down the extension of the rod, and pinch onto the tip of the rod. In this presentation, performance of hybrid diodes will be compared with the baseline diode.

Nelson, D. S. [NSTec; Berninger, M. J. [NSTec; Flores, P. A. [NSTec; Good, D. E. [NSTec; Henderson, D. J. [NSTec; Hogge, K. W. [NSTec; Huber, S. R. [NSTec; Lutz, S. S. [NSTec; Mitchell, S. E. [NSTec; Howe, R. A. [NSTec; Mitton, C. V. [NSTec; Molina, I. [NSTec; Bozman, D. R. [SNL; Cordova, S. R. [SNL; Mitchell, D. R. [SNL; Oliver, B. V. [SNL; Ormond, E. C. [SNL

2013-06-20T23:59:59.000Z

Note: This page contains sample records for the topic "hard x-ray free-electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Gray scale x-ray mask  

DOE Patents [OSTI]

The present invention describes a method for fabricating an embossing tool or an x-ray mask tool, providing microstructures that smoothly vary in height from point-to-point in etched substrates, i.e., structure which can vary in all three dimensions. The process uses a lithographic technique to transfer an image pa