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1

Low-Charge, Hard X-Ray Free Electron Laser Driven with an X-Band Injector and Accelerator  

Science Conference Proceedings (OSTI)

After the successful operation of the Free Electron Laser in Hamburg (FLASH) and the Linac Coherent Light Source (LCLS), soft and hard x-ray free electron lasers (FELs) are being built, designed, or proposed at many accelerator laboratories. Acceleration employing lower frequency rf cavities, ranging from L-band to C-band, is usually adopted in these designs. In the first stage bunch compression, higher-frequency harmonic rf system is employed to linearize the beam's longitudinal phase space, which is nonlinearly chirped during the lower frequency rf acceleration process. In this paper, a hard x-ray FEL design using an all X-band accelerator at 11.424 GHz (from photocathode rf gun to linac end) is presented, without the assistance of any harmonic rf linearization. It achieves LCLS-like performance at low charge using X-band linac drivers, which is more versatile, efficient, and compact than ones using S-band or C-band rf technology. It employs initially 42 microns long (rms), low-charge (10 pC) electron bunches from an X-band photoinjector. An overall bunch compression ratio of roughly 100 times is proposed in a two stage bunch compressor system. The start-to-end macroparticle 3D simulation employing several computer codes is presented in this paper, where space charge, wakefields, and incoherent and coherent synchrotron radiation effects are included. Employing an undulator with a short period of 1.5 cm, a Genesis FEL simulation shows successful lasing at a wavelength of 0.15 nm with a pulse length of 2 fs and a power saturation length as short as 20 meters, which is equivalent to LCLS low-charge mode. Its overall length of both accelerators and undulators is 180 meters (much shorter than the effective LCLS overall length of 1230 meters, including an accelerator length of 1100 meters and an undulator length of 130 meters), which makes it possible to be built in places where only limited space is available.

Sun, Yipeng; Adolphsen, Chris; Limborg-Deprey, Cecile; Raubenheimer, Tor; Wu, Juhao; /SLAC

2012-04-17T23:59:59.000Z

2

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

NLE Websites -- All DOE Office Websites (Extended Search)

diffractive imaging with a soft-X-ray free-electron laser We have demonstrated flash diffractive imaging of nanostructures using pulses from the first soft-X-ray free-electron...

3

The History of X-ray Free-Electron Lasers  

Science Conference Proceedings (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

4

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

5

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

6

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

NLE Websites -- All DOE Office Websites (Extended Search)

The European X-ray Free-Electron Laser: A Progress Report Friday, December 2, 2011 - 2:00pm SLAC, Redtail Conference Room (901-108) M. Altarelli, European XFEL GmbH, Hamburg,...

7

The First Angstrom X-Ray Free-Electron Laser  

SciTech Connect

The Linac Coherent Light Source produced its first x-ray laser beam on 10 April 2009. Today it is routinely producing x-ray pulses with energy >2 mJ across the operating range from 820-8,200 eV. The facility has begun operating for atomic/molecular/optical science experiments. Performance of the facility in its first user run (1 October - 21 December) and current machine development activities will be presented. Early results from the preparations for the start of the second user run is also reported.

Galayda, John; /SLAC

2012-08-24T23:59:59.000Z

8

X-ray Free-Electron Lasers - Present and Future Capabilities [Invited  

SciTech Connect

The Linac Coherent Light Source is now in operation as an X-ray free-electron laser (FEL) user facility. It produces coherent pulses of 550-10,000 eV X-rays of duration adjustable from <10 fsto500 fs. Typical peak power is in excess of 20 GW. The facility will soon be joined by several X-ray FELs under construction around the world. This article will provide an abridged history of free-electron lasers, a description of some basic physics regarding free-electron laser light amplification, and an overview of the rapidly growing list of examples in which lasers will be used in the control and operation of X-ray FELs.

Galayda, John; Ratner, John Arthur:a Daniel F.; White, William E.; /SLAC

2011-11-16T23:59:59.000Z

9

Towards hard x-ray imaging at GHz frame rate  

SciTech Connect

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

10

Towards hard X-ray imaging at GHz frame rate  

Science Conference Proceedings (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

11

Sharper Focusing of Hard X-rays  

NLE Websites -- All DOE Office Websites (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.

12

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

Science Conference Proceedings (OSTI)

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

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

2012-04-15T23:59:59.000Z

13

Phase Contrast Microscopy with Soft and Hard X-rays  

E-Print Network (OSTI)

Calibration ­ Uses up part of dynamic range · Solution: ­ Soft x-rays: Back side Illumination ­ Hard xPhase Contrast Microscopy with Soft and Hard X-rays Using a Segmented Detector Benjamin Hornberger ­ Phase Contrast 101 · A Segmented Detector for Hard X-ray Microprobes ­ Segmented Silicon Chip ­ Charge

Homes, Christopher C.

14

Aerosol Imaging with a Soft X-ray Free Electron Laser  

SciTech Connect

Lasers have long played a critical role in the advancement of aerosol science. A new regime of ultrafast laser technology has recently be realized, the world's first soft xray free electron laser. The Free electron LASer in Hamburg, FLASH, user facility produces a steady source of 10 femtosecond pulses of 7-32 nm x-rays with 10{sub 12} photons per pulse. The high brightness, short wavelength, and high repetition rate (>500 pulses per second) of this laser offers unique capabilities for aerosol characterization. Here we use FLASH to perform the highest resolution imaging of single PM2.5 aerosol particles in flight to date. We resolve to 35 nm the morphology of fibrous and aggregated spherical carbonaceous nanoparticles that existed for less than two milliseconds in vacuum. Our result opens the possibility for high spatialand time-resolved single particle aerosol dynamics studies, filling a critical technological need in aerosol science.

Bogan, Michael J.; /SLAC /LLNL, Livermore; Boutet, Sebastien; /SLAC; Chapman, Henry N.; /DESY /Hamburg U.; Marchesini, Stefano; /LBL, Berkeley; Barty, Anton; Benner, W.Henry /LLNL, Livermore; Rohner, Urs; /LLNL, Livermore /TOFWERK AG; Frank, Matthias; Hau-Riege, Stefan P.; /LLNL, Livermore; Bajt, Sasa; /DESY; Woods, Bruce; /LLNL, Livermore; Seibert, M.M.; Iwan, Bianca; Timneanu, Nicusor; Hajdu, Janos; /Uppsala U.; Schulz, Joachim; /DESY

2011-08-22T23:59:59.000Z

15

Simulation Studies of the X-Ray Free-Electron Laser Oscillator  

SciTech Connect

Simulations of the x-ray free-electron laser (FEL) oscillator are presented that include transverse effects and realistic Bragg crystal properties with the two-dimensional code GINGER. In the present cases considered the radiation divergence is much narrower than the crystal acceptance, and the numerical algorithm can be simplified by ignoring the finite angular bandwidth of the crystal. In this regime GINGER shows that the saturated x-ray pulses have 109 photons and are nearly Fourier-limited with peak powers in excess of 1 MW. Wealso include preliminary results for a four-mirror cavity that can be tuned in wavelength over a few percent, with future plans to incorporate the full transverse response of the Bragg crystals into GINGER to more accurately model this tunable source.

Lindberg, R. R.; Shyd'ko, Y.; Kim, K.-J; Fawley, W. M.

2009-08-14T23:59:59.000Z

16

MaRIE X-Ray Free-Electron Laser Pre-Conceptual Design  

SciTech Connect

The proposed Matter-Radiation Interactions in Extremes (MaRIE) facility at the Los Alamos National Laboratory will include a 50-keV X-Ray Free-Electron Laser (XFEL), a significant extension from planned and existing XFEL facilities. To prevent an unacceptably large energy spread arsing from energy diffusion, the electron beam energy should not exceed 20 GeV, which puts a significant constraint on the beam emittance. A 100-pC baseline design is presented along with advanced technology options to increase the photon flux and to decrease the spectral bandwidth through pre-bunching the electron beam.

Carlsten, Bruce E. [Los Alamos National Laboratory; Barnes, Cris W. [Los Alamos National Laboratory; Bishofberger, Kip A. [Los Alamos National Laboratory; Duffy, Leanne D. [Los Alamos National Laboratory; Heath, Cynthia E. [Los Alamos National Laboratory; Marksteiner, Quinn R. [Los Alamos National Laboratory; Nguyen, Dinh Cong [Los Alamos National Laboratory; Russell, Steven J. [Los Alamos National Laboratory; Ryne, Robert D. [Los Alamos National Laboratory; Sheffield, Richard L. [Los Alamos National Laboratory; Simakov, Evgenya I. [Los Alamos National Laboratory; Yampolsky, Nikolai A. [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

17

Femtosecond X-Ray Free Electron Laser Pulse Duration Measurement from Spectral Correlation Function  

SciTech Connect

We present a novel method for measuring the duration of femtosecond x-ray pulses from self-amplified spontaneous emission free electron lasers by performing statistical analysis in the spectral domain. Analytical expressions of the spectral correlation function were derived in the linear regime to extract both the pulse duration and the spectrometer resolution. Numerical simulations confirmed that the method can be also used in the nonlinear regime. The method was demonstrated experimentally at the Linac Coherent Light Source by measuring pulse durations down to 13 fs FWHM.

Lutman, A. A

2012-04-17T23:59:59.000Z

18

Hard X-ray Variability of AGN  

E-Print Network (OSTI)

Aims: Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods: The first 9 months of the Swift/BAT all-sky survey are used to study the 14 - 195 keV variability of the 44 brightest AGN. The sources have been selected due to their detection significance of >10 sigma. We tested the variability using a maximum likelihood estimator and by analysing the structure function. Results: Probing different time scales, it appears that the absorbed AGN are more variable than the unabsorbed ones. The same applies for the comparison of Seyfert 2 and Seyfert 1 objects. As expected the blazars show stronger variability. 15% of the non-blazar AGN show variability of >20% compared to the average flux on time scales of 20 days, and 30% show at least 10% flux variation. All the non-blazar AGN which show strong variability are low-luminosity objects with L(14-195 keV) < 1E44 erg/sec. Conclusions: Concerning the variability pattern, there is a tendency of unabsorbed or type 1 galaxies being less variable than the absorbed or type 2 objects at hardest X-rays. A more solid anti-correlation is found between variability and luminosity, which has been previously observed in soft X-rays, in the UV, and in the optical domain.

V. Beckmann; S. D. Barthelmy; T. J. -L. Courvoisier; N. Gehrels; S. Soldi; J. Tueller; G. Wendt

2007-09-14T23:59:59.000Z

19

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

NLE Websites -- All DOE Office Websites (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

20

Influence of diffraction in crystals on the coherence properties of X-ray free-electron laser pulses  

SciTech Connect

The spatial and temporal evolution of the field of random X-ray femtosecond pulses and their coherent properties upon pulse propagation in free space and under dynamical diffraction in perfect crystals in the Bragg and Laue geometries has been analyzed on the basis of the formalism developed in statistical optics. Particular attention is paid to the influence of large pulse propagation distances, which are characteristic of lengthy channels of X-ray free-electron lasers.

Bushuev, V. A., E-mail: vabushuev@yandex.ru [Moscow State University (Russian Federation); Samoylova, L. [European XFEL GmbH (Germany)

2011-09-15T23:59:59.000Z

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

Hard X-Ray Quad Collimator  

Technology Development and Commercialization Division One of the best ways to obtain small?size x?ray beams for structural biology research is to ...

22

Hard X-ray Phase Contrast -Techniques and Applications -  

E-Print Network (OSTI)

Hard X-ray Phase Contrast Microscopy - Techniques and Applications - A Dissertation Presented of the Graduate School ii #12;Abstract of the Dissertation Hard X-ray Phase Contrast Microscopy - Techniques . . . . . . . . . . . . . . . . . . 58 3.2.4 Reconstruction Example for Integration Method . . . . 59 3.2.5 The Imaginary Part

23

World's First Hard X-ray Laser  

NLE Websites -- All DOE Office Websites (Extended Search)

LCLS is the world's most powerful X-ray laser. Its highly focused beam, which arrives in staccato bursts a few quadrillionths of a second long, allows researchers to probe complex,...

24

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

SciTech Connect

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

Xiang, Dao; Ding, Yuantao; Raubenheimer, Tor; Wu, Juhao; /SLAC

2012-05-10T23:59:59.000Z

25

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

Science Conference Proceedings (OSTI)

Several recent reports have identified the scientific requirements for a future soft x-ray light source, and a high-repetition-rate free-electron laser (FEL) facility that is responsive to these requirements is now on the horizon. R&D in some critical areas is needed, however, to demonstrate technical performance, thus reducing technical risks and construction costs. Such a facility most likely will be based on a CW superconducting linear accelerator with beam supplied by a high-brightness, high-repetition-rate photocathode electron gun operating in CW mode, and on an array of FELs to which the accelerated beam is distributed, each operating at high repetition rate and with even pulse spacing. Dependent on experimental requirements, the individual FELs can be configured for either self-amplified spontaneous emission (SASE), seeded, or oscillator mode of operation, including the use of high-gain harmonic generation (HGHG), echo-enhanced harmonic generation (EEHG), harmonic cascade, or other configurations. In this White Paper we identify the overall accelerator R&D needs, and highlight the most important pre-construction R&D tasks required to value-engineer the design configuration and deliverables for such a facility. In Section 1.4 we identify the comprehensive R&D ultimately needed. We identify below the highest-priority requirements for understanding machine performance and reduce risk and costs at this pre-conceptual design stage. Details of implementing the required tasks will be the subject of future evaluation. Our highest-priority R&D program is the injector, which must be capable of delivering a beam with bunches up to a nanocoulomb at MHz repetition rate and with normalized emittance {le} 1 mm {center_dot} mrad. This will require integrated accelerating structure, cathode, and laser systems development. Cathode materials will impact the choice of laser technology in wavelength and energy per pulse, as well as vacuum requirements in the accelerating structure. Demonstration experiments in advanced seeding techniques, such as EEHG, and other optical manipulations to enhance the FEL process are required to reduce technical risk in producing temporally coherent and ultrashort x-ray output using optical seed lasers. Success of EEHG in particular would result in reduced development and cost of laser systems and accelerator hardware for seeded FELs. With a 1.5-2.5 GeV linac, FELs could operate in the VUV-soft x-ray range, where the actual beam energy will be determined by undulator technology; for example, to use the lower energy would require the use of advanced designs for which undulator R&D is needed. Significant reductions in both unit costs and accelerator costs resulting from the lower electron beam energy required to achieve lasing at a particular wavelength could be obtained with undulator development. Characterization of the wakefields of the vacuum chambers in narrow-gap undulators will be needed to minimize risk in ability to deliver close to transform limited pulses. CW superconducting RF technology for an FEL facility with short bunches at MHz rate and up to mA average current will require selection of design choices in cavity frequency and geometry, higher order mode suppression and power dissipation, RF power supply and distribution, accelerating gradient, and cryogenics systems. R&D is needed to define a cost and performance optimum. Developments in laser technology are proceeding at rapid pace, and progress in high-power lasers, harmonic generation, and tunable sources will need to be tracked.

Corlett, John; Attwood, David; Byrd, John; Denes, Peter; Falcone, Roger; Heimann, Phil; Leemans, Wim; Padmore, Howard; Prestemon, Soren; Sannibale, Fernando; Schlueter, Ross; Schroeder, Carl; Staples, John; Venturini, Marco; Warwick, Tony; Wells, Russell; Wilcox, Russell; Zholent, Alexander; Adolphsen, Chris; Arthur, John; Bergmann, Uwe; Cai, Yunhai; Colby, Eric; Dowell, David; Emma, Paul; Fox, John; Frisch, Josef; Galayda, John; Hettel, Robert; Huang, Zhirong; Phinney, Nan; Rabedeau, Tom; Raubenheimer, Tor; Reis, David; Schmerge, John; Sthr, Joachim; Stupakov, Gennady; White, Bill; Xiang, Dao

2009-06-08T23:59:59.000Z

26

A setup for resonant inelastic soft x-ray scattering on liquids at free electron laser light sources  

SciTech Connect

We present a flexible and compact experimental setup that combines an in vacuum liquid jet with an x-ray emission spectrometer to enable static and femtosecond time-resolved resonant inelastic soft x-ray scattering (RIXS) measurements from liquids at free electron laser (FEL) light sources. We demonstrate the feasibility of this type of experiments with the measurements performed at the Linac Coherent Light Source FEL facility. At the FEL we observed changes in the RIXS spectra at high peak fluences which currently sets a limit to maximum attainable count rate at FELs. The setup presented here opens up new possibilities to study the structure and dynamics in liquids.

Kunnus, Kristjan; Schreck, Simon; Foehlisch, Alexander [Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Strasse 24/25, 14476 Potsdam (Germany); Rajkovic, Ivan; Quevedo, Wilson; Gruebel, Sebastian; Scholz, Mirko [IFG Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37070 Goettingen (Germany); Eckert, Sebastian; Beye, Martin; Suljoti, Edlira; Weniger, Christian; Wernet, Philippe [Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Kalus, Christian [Abteilung Betrieb Beschleuniger BESSYII, Helmholtz-Zentrum Berlin GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Zhang, Wenkai; Hartsock, Robert W.; Gaffney, Kelly J. [PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Schlotter, William F.; Turner, Joshua J. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Kennedy, Brian [MAX-lab, PO Box 118, 221 00 Lund (Sweden); and others

2012-12-15T23:59:59.000Z

27

Refractive Optics for Hard X-ray Transmission Microscopy  

Science Conference Proceedings (OSTI)

For hard x-ray transmission microscopy at photon energies higher than 15 keV we design refractive condenser and imaging elements to be used with synchrotron light sources as well as with x-ray tube sources. The condenser lenses are optimized for low x-ray attenuation--resulting in apertures greater than 1 mm--and homogeneous intensity distribution on the detector plane, whereas the imaging enables high-resolution (condenser and imaging lenses are being developed. The imaging lenses (compound refractive lenses, CRLs) are made of SU-8 negative resist by deep x-ray lithography. SU-8 shows high radiation stability. The fabrication technique enables high-quality lens structures regarding surface roughness and arrangement precision with arbitrary 2D geometry. To provide point foci, crossed pairs of lenses are used. Condenser lenses have been made utilizing deep x-ray lithographic patterning of thick SU-8 layers, too, whereas in this case, the aperture is limited due to process restrictions. Thus, in terms of large apertures, condenser lenses made of structured and rolled polyimide film are more attractive. Both condenser types, x-ray mosaic lenses and rolled x-ray prism lenses (RXPLs), are considered to be implemented into a microscope setup. The x-ray optical elements mentioned above are characterized with synchrotron radiation and x-ray laboratory sources, respectively.

Simon, M.; Last, A.; Mohr, J.; Nazmov, V.; Reznikova, E. [Institute for Microstructure Technology, Karlsruhe Institute of Technology Kaiserstrasse 12, 76131 Karlsruhe (Germany); Ahrens, G.; Voigt, A. [Microresist Technology, Koepenikerstrasse 325, 12555 Berlin (Germany)

2011-09-09T23:59:59.000Z

28

YOHKOH remnants: partially occulted flares in hard X-rays  

E-Print Network (OSTI)

Flares being partially occulted by the solar limb, are the best reservoir of our knowledge about hard X-ray loop-top sources. Recently, the survey of partially occulted flares observed by the RHESSI has been published (Krucker & Lin 2008). The extensive YOHKOH database still awaits such activities. This work is an attempt to fill this gap. Among from 1286 flares in the YOHKOH Hard X-ray Telescope Flare Catalogue, for which the hard X-ray images had been enclosed, we identified 98 events that occurred behind the solar limb. We investigated their hard X-ray spectra and spatial structure. We found that in most cases the hard X-ray spectrum of partially occulted flares consists of two components, non-thermal and thermal, which are co-spatial. The photon energy spectra of the partially occulted flares are systematically steeper than spectra of the non-occulted flares. Such a difference we explain as a consequence of intrinsically dissimilar conditions ruling in coronal parts of flares, in comparison with the f...

Tomczak, M

2009-01-01T23:59:59.000Z

29

Design Optimization for an X-Ray Free Electron Laser Driven by SLAC Linac  

E-Print Network (OSTI)

FREE ELECTRON LASER DRIVEN BY SLAC LINAC Ming Xie, LawrenceLaser (FEL) driven by the SLAC linac. The study assumes theis carried out for the SLAC FEL over all independent system

Xie, Ming

1994-01-01T23:59:59.000Z

30

Microscopic linear liquid streams in vacuum: Injection of solvated biological samples into X-ray free electron lasers  

SciTech Connect

Microscopic linear liquid free-streams offer a means of gently delivering biological samples into a probe beam in vacuum while maintaining the sample species in a fully solvated state. By employing gas dynamic forces to form the microscopic liquid stream (as opposed to a conventional solid-walled convergent nozzle), liquid free-streams down to 300 nm diameter have been generated. Such 'Gas Dynamic Virtual Nozzles' (GDVN) are ideally suited to injecting complex biological species into an X-ray Free Electron Laser (XFEL) to determine the structure of the biological species via Serial Femtosecond Crystallography (SFX). GDVN injector technology developed for this purpose is described.

Doak, R. B.; DePonte, D. P.; Nelson, G.; Camacho-Alanis, F.; Ros, A.; Spence, J. C. H.; Weierstall, U. [Arizona State University, Tempe, AZ 85287-1504 (United States); Centre for Free-Electron Laser Science, DESY, D-22607 Hamburg (Germany); Arizona State University, Tempe, AZ 85287-1504 (United States)

2012-11-27T23:59:59.000Z

31

Bonded multilayer Laue Lens for focusing hard x-rays.  

SciTech Connect

We have fabricated partial Multilayer Laue Lens (MLL) linear zone plate structures with thousands of alternating WSi{sub 2} and Si layers and various outermost zone widths according to the Fresnel zone plate formula. Using partial MLL structures, we were able to focus hard X-rays to line foci with a width of 30 nm and below. Here, we describe challenges and approaches used to bond these multilayers to achieve line and point focusing. Bonding was done by coating two multilayers with AuSn and heating in a vacuum oven at 280-300 C. X-ray reflectivity measurements confirmed that there was no change in the multilayers after heating to 350 C. A bonded MLL was polished to a 5-25 {micro}m wedge without cracking. SEM image analyses found well-positioned multilayers after bonding. These results demonstrate the feasibility of a bonded full MLL for focusing hard X-rays.

Liu, C.; Conley, R.; Qian, J.; Kewish, C.M.; Macrander, A.T.; Maser, J.; Kang, H.C.; Yan, H.; Stephenson, G.B.; Advanced Photonics Research Institute; Gwangju Institute of Science and Technology

2007-11-11T23:59:59.000Z

32

X-RAY NONLINEAR OPTICAL PROCESSES IN ATOMS USING A SELF-AMPLIFIED SPONTANEOUS EMISSION FREE-ELECTRON LASER  

SciTech Connect

X-ray free electron lasers (xFEL) will open new avenues to the virtually unexplored territory of non-linear interactions of x rays with matter. Initially xFELs will be based on the principle of self-amplified spontaneous emission (SASE). Each SASE pulse consists of a number of coherent intensity spikes of random amplitude, i.e. the process is chaotic and pulses are irreproducible. The coherence time of SASE xFELs will be a few femtoseconds for a photon energy near 1 keV. The importance of coherence properties of light in non-linear optical processes was theoretically discovered in the early 1960s. In this contribution we will illustrate the impact of field chaoticity on x-ray non-linear optical processes on neon for photon energies around 1 keV and intensities up to 10{sup 18} W/cm{sup 2}. Resonant and non-resonant processes are discussed. The first process to be addressed is the formation of a double-core hole in neon by photoionization with x rays above 1.25 keV energy. In contrast to the long-wavelength regime, non-linear optical processes in the x-ray regime are characterized in general by sequential single-photon single-electron interactions. Despite this fact, the sequential absorption of multiple x-ray photons depends on the statistical properties of the radiation field. Treating the x rays generated by a SASE FEL as fully chaotic, a quantum-mechanical analysis of inner-shell two-photon absorption is performed. By solving a system of time-dependent rate equations, we demonstrate that double-core hole formation in neon via x-ray two-photon absorption is enhanced by chaotic photon statistics. At an intensity of 10{sup 16} W/cm{sup 2}, the statistical enhancement is about 30%, much smaller than typical values in the optical regime. The second part of this presentation discusses the resonant Auger effect of atomic neon at the 1s-3p transition (at 867.1 eV). For low X-ray intensity, the excitation process 1s {yields} 3p in Neon can be treated perturbatively. The core-hole excited 1s{sup -1} 3p state is embedded in the continuum and decays via Auger-process on the timescale of approximately 5 fs. Increasing the x-ray intensity above 1.5 x 10{sup 18} W/cm{sup 2}, a peak intensity accessible with xFEL sources in the near future, x-ray induced emission from 3p back to 1s becomes possible, i.e. Rabi oscillations between these two levels can be induced. For the numerical analysis of this process, an effective two-level model, including a description of the resonant Auger decay process, is employed. The observation of x-ray-driven atomic populations dynamics in the time domain is challenging for chaotic xFEL pulses. In addition to requiring single-shot measurements, sub-femtosecond temporal resolution would be needed. The Rabi oscillations will, however, be imprinted on the kinetic energy distribution of the resonant Auger electron (see Fig. 1). Measuring the resonant Auger-electron line profile will provide information on both atomic population dynamics and x-ray pulse properties.

Rohringer, N

2008-08-08T23:59:59.000Z

33

Phase Contrast Microscopy with Soft and Hard X-rays Using a Segmented  

E-Print Network (OSTI)

Phase Contrast Microscopy with Soft and Hard X-rays Using a Segmented Detector A Dissertation Contrast Microscopy with Soft and Hard X-rays Using a Segmented Detector by Benjamin Hornberger Doctor. In the hard x-ray range (multi-keV), the main focus lies on trace ele- ment mapping by x-ray fluorescence

34

HARD X-RAY AND MICROWAVE OBSERVATIONS OF MICROFLARES Jiong Qiu,1, 2  

E-Print Network (OSTI)

HARD X-RAY AND MICROWAVE OBSERVATIONS OF MICROFLARES Jiong Qiu,1, 2 Chang Liu,2 Dale E. Gary,2 Gelu, we study solar microflares using the coordinated hard X-ray and microwave observations obtained the time derivative of soft X-rays and 14­20 keV hard X-rays, i.e., the Neupert effect, in about one

35

Argonne CNM Highlight: World?s Most Precise ?Hard X-Ray?  

NLE Websites -- All DOE Office Websites (Extended Search)

World's Most Precise "Hard X-Ray" Nanoprobe Activated X-rays from an APS undulator exiting the front end window of the nanoprobe beamline. X-rays from an APS undulator exiting the...

36

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

37

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

38

The Turn-on of LCLS: the X-Ray Free Electron Laser at SLAC ( Keynote - 2011 JGI User Meeting)  

Science Conference Proceedings (OSTI)

The U.S. Department of Energy Joint Genome Institute (JGI) invited scientists interested in the application of genomics to bioenergy and environmental issues, as well as all current and prospective users and collaborators, to attend the annual DOE JGI Genomics of Energy & Environment Meeting held March 22-24, 2011 in Walnut Creek, Calif. The emphasis of this meeting was on the genomics of renewable energy strategies, carbon cycling, environmental gene discovery, and engineering of fuel-producing organisms. The meeting features presentations by leading scientists advancing these topics. SLAC National Laboratory Director Persis Drell gives a keynote talk on "The Turn-on of LCLS: the X-Ray Free-Electron Laser at SLAC" at the 6th Genomics of Energy & Environment Meeting on March 22, 2011

Drell, Persis [SLAC Director

2011-03-22T23:59:59.000Z

39

Imaging of micro-and nano-structures with hard X-rays  

E-Print Network (OSTI)

object with the hard X-ray microscope A horizontal line profile is inserted in the upper right partImaging of micro- and nano-structures with hard X-rays C. Rau, V. Crecea, C.-P. Richter, K Abstract: Imaging of micro- and nano-structures of opaque samples is demonstrated using hard X-rays. Two

Braun, Paul

40

Combined use of hard X-ray phase contrast imaging and X-ray fluorescence microscopy for sub-cellular metal quantification  

E-Print Network (OSTI)

Combined use of hard X-ray phase contrast imaging and X-ray fluorescence microscopy for subSurface Science Laboratory at the European Synchrotron Radiation Facility, Grenoble, France Abstract Hard X of the details of cells are undetectable in hard X-ray microscopy due to the weak absorption contrast between

Paris-Sud XI, Université de

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

X-ray-optical cross-correlator for gas-phase experiments at the Linac Coherent Light Source free-electron laser  

Science Conference Proceedings (OSTI)

X-ray-optical pump-probe experiments at the Linac Coherent Light Source (LCLS) have so far been limited to a time resolution of 280 fs fwhm due to timing jitter between the accelerator-based free-electron laser (FEL) and optical lasers. We have implemented a single-shot cross-correlator for femtosecond x-ray and infrared pulses. A reference experiment relying only on the pulse arrival time information from the cross-correlator shows a time resolution better than 50 fs fwhm (22 fs rms) and also yields a direct measurement of the maximal x-ray pulse length. The improved time resolution enables ultrafast pump-probe experiments with x-ray pulses from LCLS and other FEL sources.

Schorb, S.; Cryan, J. P.; Glownia, J. M.; Bionta, M. R.; Coffee, R. N.; Swiggers, M.; Carron, S.; Castagna, J.-C.; Bozek, J. D.; Messerschmidt, M.; Schlotter, W. F.; Bostedt, C. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, P.O. Box 20450, Stanford, California 94309 (United States); Gorkhover, T. [Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Erk, B.; Boll, R.; Schmidt, C.; Rudenko, A. [Max-Planck Advanced-Study-Group at CFEL, Notkestr. 85, 22607 Hamburg (Germany); Max-Planck-Institut f. Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Rolles, D. [Max-Planck Advanced-Study-Group at CFEL, Notkestr. 85, 22607 Hamburg (Germany); Max-Planck-Institut f. med. Forschung, Jahnstr. 29, 69120 Heidelberg (Germany); Rouzee, A. [Max-Born-Institut, Max-Born-Str. 2, 12489 Berlin (Germany)

2012-03-19T23:59:59.000Z

42

Low dose hard x-ray contact microscopy assisted by a photoelectric conversion layer  

SciTech Connect

Hard x-ray contact microscopy provides images of dense samples at resolutions of tens of nanometers. However, the required beam intensity can only be delivered by synchrotron sources. We report on the use of a gold photoelectric conversion layer to lower the exposure dose by a factor of 40 to 50, allowing hard x-ray contact microscopy to be performed with a compact x-ray tube. We demonstrate the method in imaging the transmission pattern of a type of hard x-ray grating that cannot be fitted into conventional x-ray microscopes due to its size and shape. Generally the method is easy to implement and can record images of samples in the hard x-ray region over a large area in a single exposure, without some of the geometric constraints associated with x-ray microscopes based on zone-plate or other magnifying optics.

Gomella, Andrew; Martin, Eric W.; Lynch, Susanna K.; Wen, Han [Imaging Physics Laboratory, Biophysics and Biochemistry Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892 (United States); Morgan, Nicole Y. [Intramural Research Programs, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892 (United States)

2013-04-15T23:59:59.000Z

43

Hard-X-Ray Optics Development at Marshall Space Flight Center  

E-Print Network (OSTI)

This paper summarizes the current status of the development of hard-X-ray optics using nickel replication at NASA's Marshall Space Flight Center.

Brian D. Ramsey; Martin C. Weisskopf

2004-03-18T23:59:59.000Z

44

Toward TW-Level, Hard X-Ray Pulses at LCLS  

Science Conference Proceedings (OSTI)

Coherent diffraction imaging of complex molecules such as proteins requires a large number (e.g., {approx} 10{sup 13}/pulse) of hard X-ray photons within a time scale of {approx} 10 fs or less. This corresponds to a peak power of {approx} 1 TW, much larger than that currently generated by LCLS or other proposed X-ray free electron lasers (FELs). We study the feasibility of producing such pulses using a LCLS-like, low charge electron beam, as will be possible in the LCLS-II upgrade project, employing a configuration beginning with a SASE amplifier, followed by a 'self-seeding' crystal monochromator, and finishing with a long tapered undulator. Our results suggest that TW-level output power at 8.3 keV is possible from a total undulator system length around 200 m. In addition power levels larger than 100 GW are generated at the third harmonic. We present a tapering strategy that extends the original 'resonant particle' formalism by optimizing the transport lattice to maximize optical guiding and enhance net energy extraction. We discuss the transverse and longitudinal coherence properties of the output radiation pulse and the expected output pulse energy sensitivity, both to taper errors and to power fluctuations on the monochromatized SASE seed.

Fawley, W.M.; Frisch, J.; Huang, Z.; Jiao, Y.; Nuhn, H.-D.; /SLAC; Pellegrini, C.; /SLAC /UCLA; Reiche, S.; /PSI, Villigen; Wu, J,; /SLAC

2011-12-13T23:59:59.000Z

45

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

SciTech Connect

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

46

Exploring electronic structure through high-resolution hard x-ray  

NLE Websites -- All DOE Office Websites (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

47

The Ulysses Catalog of Solar Hard X-Ray Flares  

E-Print Network (OSTI)

rupted full-Sun coverage of major solar X-ray ?are activity.of Ulysses from the Sun in AU, and its solar longitude andof the solar disk shows the view of the Sun from Earth,

Tranquille, C.; Hurley, K.; Hudson, H. S.

2009-01-01T23:59:59.000Z

48

The Ulysses Catalog of Solar Hard X-Ray Flares  

E-Print Network (OSTI)

its Solar X-ray/Cosmic Gamma-Ray Burst Experiment (GRB) hasInstrument The Ulysses Gamma-Ray Burst (GRB) instrument, hasrate due to a cosmic gamma-ray burst or a solar ?are, but we

Tranquille, C.; Hurley, K.; Hudson, H. S.

2009-01-01T23:59:59.000Z

49

The emerging population of pulsar wind nebulae in hard X-rays  

E-Print Network (OSTI)

The hard X-ray synchrotron emission from pulsar wind nebulae (PWNe) probes energetic particles, closely related to the pulsar injection power at the present time. INTEGRAL has disclosed the yet poorly known population of hard X-ray pulsar/PWN systems. We summarize the properties of the class, with emphasys on the first hard X-ray bow-shock (CTB 80 powered by PSR B1951+32), and highlight some prospects for the study of Pulsar Wind Nebulae with the Simbol-X mission.

Mattana, Fabio; Terrier, Rgis; Renaud, Matthieu; Falanga, Maurizio

2009-01-01T23:59:59.000Z

50

Real Time in situ hard X-ray texture evolution during the annealing of rolled CuNi tapes  

E-Print Network (OSTI)

1 Real Time in situ hard X-ray texture evolution during the annealing of rolled CuNi tapes Antoine monochromators. It uses a white hard X ray beam and works in transmission geometry. The 2D detector allows, used as substrate for high temperature superconductor, is presented. hard X-rays; diffraction; in

Paris-Sud XI, Université de

51

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

Science Conference Proceedings (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

52

Hard X-ray Phase-Contrast Tomographic Nanoimaging  

Science Conference Proceedings (OSTI)

Synchrotron-based full-field tomographic microscopy established itself as a tool for noninvasive investigations. Many beamlines worldwide routinely achieve micrometer spatial resolution while the isotropic 100-nm barrier is reached and trespassed only by few instruments, mainly in the soft x-ray regime. We present an x-ray, full-field microscope with tomographic capabilities operating at 10 keV and with a 3D isotropic resolution of 144 nm recently installed at the TOMCAT beamline of the Swiss Light Source. Custom optical components, including a beam-shaping condenser and phase-shifting dot arrays, were used to obtain an ideal, aperture-matched sample illumination and very sensitive phase-contrast imaging. The instrument has been successfully used for the nondestructive, volumetric investigation of single, unstained cells.

Stampanoni, M. [Paul Scherrer Institut, 5232 Villigen (Switzerland); Institute for Biomedical Engineering, University and ETH Zuerich, 8092 Zuerich (Switzerland); Marone, F.; Vila-Comamala, J.; Gorelick, S.; David, C.; Mokso, R. [Paul Scherrer Institut, 5232 Villigen (Switzerland); Trtik, P.; Jefimovs, K. [EMPA, Swiss Federal Laboratories for Materials Science and Technology, 8600 Duebendorf (Switzerland)

2011-09-09T23:59:59.000Z

53

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

SciTech Connect

A dense electron beam propagating through a laser undulator can radiate a coherent x-ray or gamma ray. This lasing scheme is studied with the Landau damping theory. The analysis suggests that, with currently available physical parameters, coherent gamma rays of up to 50 keV can be generated. The electron quantum diffraction suppresses the free electron laser action, which limits the maximum radiation.

Son, S. [18 Caleb Lane, Princeton, New Jersey 08540 (United States); Joon Moon, Sung [8 Benjamin Rush Ln., Princeton, New Jersey 08540 (United States)

2012-06-15T23:59:59.000Z

54

Compact X-ray Free Electron Laser from a Laser-plasma Accelerator using a Transverse Gradient Undulator  

SciTech Connect

Compact laser-plasma accelerators can produce high energy electron beams with low emittance, high peak current but a rather large energy spread. The large energy spread hinders the potential applications for coherent FEL radiation generation. In this paper, we discuss a method to compensate the effects of beam energy spread by introducing a transverse field variation into the FEL undulator. Such a transverse gradient undulator together with a properly dispersed beam can greatly reduce the effects of electron energy spread and jitter on FEL performance. We present theoretical analysis and numerical simulations for SASE and seeded extreme ultraviolet and soft x-ray FELs based on laser plasma accelerators.

Huang, Zhirong; Ding, Yuantao; /SLAC; Schroeder, Carl B.; /LBL, Berkeley

2012-09-13T23:59:59.000Z

55

Analysis of hard X-ray eclipse in SS433 from INTEGRAL observations  

E-Print Network (OSTI)

The analysis of hard X-ray INTEGRAL observations (2003-2008) of superaccreting galactic microquasar SS433 at precessional phases of the source with the maximum disk opening angle is carried out. It is found that the shape and width of the primary X-ray eclipse is strongly variable suggesting additional absorption in dense stellar wind and gas outflows from the optical A7I-component and the wind-wind collision region. The independence of the observed hard X-ray spectrum on the accretion disk precessional phase suggests that hard X-ray emission (20-100 keV) is formed in an extended, hot, quasi-isothermal corona, probably heated by interaction of relativistic jet with inhomogeneous wind outflow from the precessing supercritical accretion disk. A joint modeling of X-ray eclipsing and precessional hard X-ray variability of SS433 revealed by INTEGRAL by a geometrical model suggests the binary mass ratio $q=m_x/m_v\\simeq 0.25\\div 0.5$. The absolute minimum of joint orbital and precessional $\\chi^2$ residuals is reac...

Cherepashchuk, A M; Postnov, K A; Antokhina, E A; Molkov, S V

2009-01-01T23:59:59.000Z

56

Optimal focusing for a linac-based hard x-ray source  

Science Conference Proceedings (OSTI)

In spite of having a small average beam current limit, a linac can have features that make it attractive as an x-ray source: high energy, ultralow emittance and energy spread, and flexible beamline optics. Unlike a storage ring, in which an (undulator) radiation source is necessarily short and positioned at an electron beam waist, in a linac the undulator can be long and the electron beam can be adjusted to have a (virtual) waist far downstream toward the x-ray target. Using a planned CEBAF beamline as an example, this paper shows that a factor of 2000 in beam current can be overcome to produce a monochromatic hard x-ray source comparable with, or even exceeding, the performance of an x-ray line at a third generation storage ring. Optimal electron beam focusing conditions for x-ray flux density and brilliance are derived, and are verified by simulations using the SRW code.

Liu, C.; Krafft, G.; Talman, R.

2011-03-28T23:59:59.000Z

57

Shielding Calculations for the Hard X-Rays Generated by LCLS Mec Laser System  

Science Conference Proceedings (OSTI)

Linac Coherent Light Source (LCLS) Matter in Extreme Conditions (MEC) Instrument is an X-ray instrument that will be able to create and diagnose High Energy Density (HED) matter. The MEC laser system can generate hard X-ray due to the interaction of the laser and the plasma. This paper summarizes results of the shielding calculations performed to evaluate the radiation hazards induced by this hard X-ray source with Monte Carlo code FLUKA. The dose rates and photon spectra due to this X-ray source are calculated at different locations with different shielding. The influence of the electron temperature on the source terms and the shielding effectiveness was also investigated.

Not Available

2011-06-02T23:59:59.000Z

58

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

NLE Websites -- All DOE Office Websites (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

59

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

SciTech Connect

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

60

Measurement of Hard X-ray Lens Wavefront Aberrations using Phase Retrieval  

Science Conference Proceedings (OSTI)

Measuring the deviation of a wavefront from a sphere provides valuable feedback on lens alignment and manufacturing errors. We demonstrate that these aberrations can be accurately measured at hard x-ray wavelengths, from far-field intensity measurements, using phase retrieval with a moveable structure in the beam path. We induce aberrations on a hard x-ray kinoform lens through deliberate misalignment and show that the reconstructed wavefronts are in good agreement with numerical simulations. Reconstructions from independent data, with the structure at different longitudinal positions and significantly separated from the beam focus, agreed with a root mean squared error of 0.006 waves.

M Guizer-Sicairos; S Narayanan; A Stein; M Metzler; A Sandy; J Fienup; K Evans-Lutterodt

2011-12-31T23:59:59.000Z

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

Measurement of hard x-ray lens wavefront aberrations using phase retrieval  

Science Conference Proceedings (OSTI)

Measuring the deviation of a wavefront from a sphere provides valuable feedback on lens alignment and manufacturing errors. We demonstrate that these aberrations can be accurately measured at hard x-ray wavelengths, from far-field intensity measurements, using phase retrieval with a moveable structure in the beam path. We induce aberrations on a hard x-ray kinoform lens through deliberate misalignment and show that the reconstructed wavefronts are in good agreement with numerical simulations. Reconstructions from independent data, with the structure at different longitudinal positions and significantly separated from the beam focus, agreed with a root mean squared error of 0.006 waves.

Guizar-Sicairos, M.; Evans-Lutterodt, K.; Narayanan, S.; Stein, A.; Metzler, M.; Sandy, A.R.; Fienup, J.R.

2011-03-15T23:59:59.000Z

62

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

NLE Websites -- All DOE Office Websites (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

63

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

NLE Websites -- All DOE Office Websites (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,

64

A bright point source of ultrashort hard x-rays from laser bioplasmas  

E-Print Network (OSTI)

Micro and nano structures scatter light and amplify local electric fields very effectively. Energy incident as intense ultrashort laser pulses can be converted to x-rays and hot electrons more efficiently with a substrate that suitably modifies the local fields. Here we demonstrate that coating a plain glass surface with a few micron thick layer of an ubiquitous microbe, {\\it Escherichia coli}, catapults the brightness of hard x-ray bremsstrahlung emission (up to 300 keV) by more than two orders of magnitude at an incident laser intensity of 10$^{16}$ W cm$^{-2}$. This increased yield is attributed to the local enhancement of electric fields around individual {\\it E. coli} cells and is reproduced by detailed particle-in-cell (PIC) simulations. This combination of laser plasmas and biological targets can lead to turnkey, multi-kilohertz and environmentally safe sources of hard x-rays.

Krishnamurthy, M; Lad, Amit D; Ahmad, Saima; Narayanan, V; Rajeev, R; Kundu, M; Kumar, G Ravindra; Ray, Krishanu

2010-01-01T23:59:59.000Z

65

Coherent hard x-ray diffractive imaging of nonisolated objects confined by an aperture  

Science Conference Proceedings (OSTI)

Coherent hard x-ray imaging of nonisolated weak phase objects is demonstrated by confining x-ray beam in a region of a few micrometers in cross section using a micrometer-sized aperture. Two major obstacles in the hard x-ray coherent diffraction imaging, isolating samples and obtaining central speckles, are addressed by using the aperture. The usefulness of the proposed method is illustrated by reconstructing the exit wave field of a nanoscale trench structure fabricated on silicon which serves as a weak phase object. The quantitative phase information of the exit wave field was used to reconstruct the depth profile of the trench structure. The scanning capability of this method was also briefly discussed.

Kim, Sunam; Kim, Chan; Lee, Suyong; Marathe, Shashidhara; Noh, D. Y.; Kang, H. C.; Kim, S. S.; Sandy, A.; Narayanan, S. [Department of Materials Science and Engineering and Nanobio Materials and Electronics, Graduate Program of Photonics and Applied Physics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Department of Advanced Materials Engineering and BK21 Education Center of Mould Technology for Advanced Materials and Parts, Chosun University, Gwangju 501-759 (Korea, Republic of); Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2010-04-15T23:59:59.000Z

66

Atomic physics with hard X-rays from high brilliance synchrotron light sources  

Science Conference Proceedings (OSTI)

A century after the discovery of x rays, the experimental capability for studying atomic structure and dynamics with hard, bright synchrotron radiation is increasing remarkably. Tempting opportunities arise for experiments on many-body effects, aspects of fundamental photon-atom interaction processes, and relativistic and quantum-electrodynamic phenomena. Some of these possibilities are surveyed in general terms.

Southworth, S.; Gemmell, D.

1996-08-01T23:59:59.000Z

67

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

Science Conference Proceedings (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

68

HARD X-RAY AND MICROWAVE EMISSIONS FROM SOLAR FLARES WITH HARD SPECTRAL INDICES  

SciTech Connect

We analyze 10 flare events that radiate intense hard X-ray (HXR) emission with significant photons over 300 keV to verify that the electrons that have a common origin of acceleration mechanism and energy power-law distribution with solar flares emit HXRs and microwaves. Most of these events have the following characteristics. HXRs emanate from the footpoints of flare loops, while microwaves emanate from the tops of flare loops. The time profiles of the microwave emission show delays of peak with respect to those of the corresponding HXR emission. The spectral indices of microwave emissions show gradual hardening in all events, while the spectral indices of the corresponding HXR emissions are roughly constant in most of the events, though rather rapid hardening is simultaneously observed in some for both indices during the onset time and the peak time. These characteristics suggest that the microwave emission emanates from the trapped electrons. Then, taking into account the role of the trapping of electrons for the microwave emission, we compare the observed microwave spectra with the model spectra calculated by a gyrosynchrotron code. As a result, we successfully reproduce the eight microwave spectra. From this result, we conclude that the electrons that have a common acceleration and a common energy distribution with solar flares emit both HXR and microwave emissions in the eight events, though microwave emission is contributed to by electrons with much higher energy than HXR emission.

Kawate, T. [Kwasan and Hida Observatory, Kitashirakawa-oiwakecho, Sakyo, Kyoto 606-8502 (Japan); Nishizuka, N. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 229-8510 (Japan); Oi, A. [College of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Ohyama, M. [Faculty of Education, Shiga University, 2-5-1 Hiratsu, Otsu, Shiga 1-1, Baba Hikone city, Siga 522-8522 (Japan); Nakajima, H., E-mail: kawate@kusastro.kyoto-u.ac.jp [Nobeyama Solar Radio Observatory, NAOJ, Nobeyama, Minamisaku, Nagano 384-1305 (Japan)

2012-03-10T23:59:59.000Z

69

One-dimensional hard x-ray field retrieval using a moveable structure  

Science Conference Proceedings (OSTI)

We present a technique that allows measuring the field of an x-ray line focus using far-field intensity measurements only. One-dimensional phase retrieval with transverse translation diversity is used to recover a hard x-ray beam focused by a compound kinoform lens. The reconstruction is found to be in good agreement with independent knife-edge scan measurements taken at separated planes. The approach avoids the need for measuring the beam profile at focus and allows narrower beams to be measured than the traditional knife-edge scan.

Guizar-Sicairos, M.; Evans-Lutterodt, K.; Isakovic, A.F.; Stein, A.; Warren, J.B.; Sandy, A.R.; Narayanan, S.; Fienup, J.R.

2010-08-16T23:59:59.000Z

70

Interferometric hard x-ray phase contrast imaging at 204 nm grating period  

SciTech Connect

We report on hard x-ray phase contrast imaging experiments using a grating interferometer of approximately 1/10th the grating period achieved in previous studies. We designed the gratings as a staircase array of multilayer stacks which are fabricated in a single thin film deposition process. We performed the experiments at 19 keV x-ray energy and 0.8 {mu}m pixel resolution. The small grating period resulted in clear separation of different diffraction orders and multiple images on the detector. A slitted beam was used to remove overlap of the images from the different diffraction orders. The phase contrast images showed detailed features as small as 10 {mu}m, and demonstrated the feasibility of high resolution x-ray phase contrast imaging with nanometer scale gratings.

Wen Han; Gomella, Andrew A.; Miao, Houxun; Lynch, Susanna K. [Imaging Physic Laboratory, Biophysics and Biochemistry Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892 (United States); Wolfe, Douglas E. [Applied Research Laboratory, Penn State University, State College, Pennsylvania 16804 (United States); Xiao Xianghui; Liu Chian [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Morgan, Nicole [National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892 (United States)

2013-01-15T23:59:59.000Z

71

A Low-Charge, Hard X-Ray FEL Driven with an X-band Injector and Accelerator  

Science Conference Proceedings (OSTI)

After the successful operation of FLASH (Free-Electron Laser in Hamburg) and LCLS (Linac Coherent Light Source), soft and hard X-ray Free Electron Lasers (FELs) are being built, designed or proposed at many accelerator laboratories. Acceleration employing lower frequency RF cavities, ranging from L-band to C-band, is usually adopted in these designs. In the first stage bunch compression, higher-frequency harmonic RF system is employed to linearize the beam's longitudinal phase space, which is nonlinearly chirped during the lower frequency RF acceleration process. In this paper, a hard X-ray FEL design using an all X-band accelerator at 11.424 GHz (from photo-cathode RF gun to linac end) is presented, without the assistance of any harmonic RF linearization. It achieves LCLS-like performance at low charge using X-band linac drivers, which is more versatile, efficient and compact than ones using S-band or C-band rf technology. It employs initially 42 microns long (RMS), low charge (10 pC) electron bunches from an X-band photoinjector. An overall bunch compression ratio of roughly 100 times is proposed in a two stage bunch compressor system. The start-to-end macro-particle 3-D simulation employing several computer codes is presented in this paper, where space charge, wakefields, incoherent and coherent synchrotron radiation (ISR and CSR) effects are included. Employing an undulator with a short period of 1.5 cm, a Genesis FEL simulation shows successful lasing at a wavelength of 0.15 nm with a pulse length of 2 fs and a power saturation length as short as 20 meters, which is equivalent to LCLS low charge mode. Its overall length of both accelerators and undulators is 180 meters (much shorter than the effective LCLS overall length of 1230 meters, including an accelerator length of 1100 meters and an undulator length of 130 meters), which makes it possible to be built in places where only limited space is available.

Sun, Yipeng; Adolphsen, Chris; Limborg-Deprey, Cecile; Raubenheimer, Tor; Wu, Juhao; /SLAC

2012-02-17T23:59:59.000Z

72

Wiggler-base Hard X-ray Spectroscopy Beamline at CLS  

Science Conference Proceedings (OSTI)

The CLS 06ID-1 Hard X-ray Micro-Analysis Beamline (HXMA) is a general purpose hard X-ray spectroscopy beamline (5 to 40 keV) designed to serve users in XAFS, diffraction and microprobe communities. The beamline uses the synchrotron radiation from a superconducting wiggler. The primary beamline optics include a 1.2 m water-cooled silicon collimating mirror (separate Rh and Pt coating stripes), a liquid nitrogen cooled double crystal monochromator (Kohzu CMJ-1) housing two crystal pairs (Si 111 and 220), and a 1.15 m long water-cooled silicon toroidal focusing mirror (separate Rh and Pt coating stripes). All mirrors are equipped with dynamical meridian benders. The experimental hutch hosts three experimental setups for XAFS, diffraction and microprobe, respectively. Primary design considerations and some commissioning results are discussed.

Jiang, D. T. [Canadian Light Source, University of Saskatchewan, Saskatoon, SK (Canada); Department of Physics, University of Guelph, Guelph ON N1G 2W1 (Canada); Chen, N. [Canadian Light Source, University of Saskatchewan, Saskatoon, SK (Canada); Geological Sciences Department, University of Saskachewan, Saskatoon, SK (Canada); Sheng, W. [Canadian Light Source, University of Saskatchewan, Saskatoon, SK (Canada)

2007-01-19T23:59:59.000Z

73

Extending synchrotron-based atomic physics experiments into the hard X-ray region  

Science Conference Proceedings (OSTI)

The high-brightness, hard x-ray beams available from third-generation synchrotron sources are opening new opportunities to study the deepest inner shells of atoms, an area where little work has been done and phenomena not observed in less tightly bound inner-shells are manifested. In addition scattering processes which are weak at lower energies become important, providing another tool to investigate atomic structure as well as an opportunity to study photon/atom interactions beyond photoabsorption. In this contribution the authors discuss some of the issues related to extending synchrotron-based atomic physics experiments into the hard x-ray region from the physical and the experimental point of view. They close with a discussion of a technique, resonant Raman scattering, that may prove invaluable in determining the spectra of the very highly-excited states resulting from the excitation of deep inner shells.

LeBrun, T. [Argonne National Lab., IL (United States). Physics Div.

1996-12-31T23:59:59.000Z

74

WEAK HARD X-RAY EMISSION FROM TWO BROAD ABSORPTION LINE QUASARS OBSERVED WITH NuSTAR: COMPTON-THICK ABSORPTION OR INTRINSIC X-RAY WEAKNESS?  

SciTech Connect

We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain Almost-Equal-To 400-600 hard X-ray ({approx}> 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (N{sub H} {approx}< 10{sup 24} cm{sup -2}). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N{sub H} Almost-Equal-To 7 Multiplication-Sign 10{sup 24} cm{sup -2} if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe K{alpha} line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

Luo, B.; Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Alexander, D. M.; Hickox, R. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Harrison, F. A.; Fuerst, F.; Grefenstette, B. W.; Madsen, K. K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Bauer, F. E. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Comastri, A. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Fiore, F. [Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone (Italy); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Matt, G. [Dipartimento di Matematica e Fisica, Universita degli Studi Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Ogle, P. [IPAC, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125 (United States); and others

2013-08-01T23:59:59.000Z

75

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

SciTech Connect

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

76

Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals  

SciTech Connect

We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub X}{approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

Stoupin, Stanislav; Shvyd'ko, Yuri; Shu Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey [Advanced Photon Source, Argonne National Laboratory, Illinois 60439 (United States)

2012-02-15T23:59:59.000Z

77

Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals.  

Science Conference Proceedings (OSTI)

We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub x} {approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

Stoupin, S.; Shvydko, Y.; Shu, D.; Khachatryan, R.; Xiao, X. (X-Ray Science Division)

2012-01-01T23:59:59.000Z

78

IMAGE SEGMENTATION FOR PHASE-CONTRAST HARD X-RAY CMT OF C/C Gerard L. Vignoles  

E-Print Network (OSTI)

1 IMAGE SEGMENTATION FOR PHASE-CONTRAST HARD X-RAY CMT OF C/C COMPOSITES Gerard L. Vignoles/C composites, computerized microtomographs have been acquired with synchrotron radiation X-rays. Due ranging between 0° and 180°, were acquired each time using a Gd2O3S:Tb scintillator, a light amplification

Paris-Sud XI, Université de

79

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

E-Print Network (OSTI)

with gas-phase targets, x-ray sources derived from solid tar- gets have superior x-ray yields in the hard x. Hulin, P. Mono, J. Abdallah, Jr., A. Y. Faenov, I. Y. Skobelev, A. I. Magunov, and T. A. Pikuz, JETP

Strathclyde, University of

80

Review on Active Galactic Nuclei at hard X-ray energies  

E-Print Network (OSTI)

Hard X-ray surveys are an important tool for the study of active galactic nuclei (AGN): they provide almost an unbiased view of absorption in the extragalactic population, allow the study of spectral features such as reflection and high energy cut-off which would otherwise be unexplored and favour the discovery of some blazars at high redshift. Here, we present the absorption properties of a large sample of INTEGRAL detected AGN, including an update on the fraction of Compton thick objects. For a sub-sample of 87 sources, which represent a complete set of bright AGN, we will discuss the hard X-ray (20-100 keV) spectral properties, also in conjunction with Swift/BAT 58 month data, providing information on BAT/IBIS cross-calibration constant, average spectral shape and spectral complexity. For this complete sample, we will also present broad-band data using soft X-ray observations, in order to explore the complexity of AGN spectra both at low and high energies and to highlight the variety of shapes. Future pros...

Bassani, Loredana; Malizia, A; Panessa, F; Landi, R; Bazzano, A; Ubertini, P; Bird, A J; Stephen, J B

2013-01-01T23:59:59.000Z

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

DIFFUSE HARD X-RAY EMISSION IN STARBURST GALAXIES AS SYNCHROTRON FROM VERY HIGH ENERGY ELECTRONS  

SciTech Connect

The origin of the diffuse hard X-ray (2-10 keV) emission from starburst galaxies is a long-standing problem. We suggest that synchrotron emission of 10-100 TeV electrons and positrons (e {sup {+-}}) can contribute to this emission, because starbursts have strong magnetic fields. We consider three sources of e {sup {+-}} at these energies: (1) primary electrons directly accelerated by supernova remnants, (2) pionic secondary e {sup {+-}} created by inelastic collisions between cosmic ray (CR) protons and gas nuclei in the dense interstellar medium of starbursts, and (3) pair e {sup {+-}} produced between the interactions between 10 and 100 TeV {gamma}-rays and the intense far-infrared (FIR) radiation fields of starbursts. We create one-zone steady-state models of the CR population in the Galactic center (R {<=} 112 pc), NGC 253, M82, and Arp 220's nuclei, assuming a power-law injection spectrum for electrons and protons. We consider different injection spectral slopes, magnetic field strengths, CR acceleration efficiencies, and diffusive escape times, and include advective escape, radiative cooling processes, and secondary and pair e {sup {+-}}. We compare these models to extant radio and GeV and TeV {gamma}-ray data for these starbursts, and calculate the diffuse synchrotron X-ray and inverse Compton (IC) luminosities of these starbursts in the models which satisfy multiwavelength constraints. If the primary electron spectrum extends to {approx}PeV energies and has a proton/electron injection ratio similar to the Galactic value, we find that synchrotron emission contributes 2%-20% of their unresolved, diffuse hard X-ray emission. However, there is great uncertainty in this conclusion because of the limited information on the CR electron spectrum at these high energies. IC emission is likewise a minority of the unresolved X-ray emission in these starbursts, from 0.1% in the Galactic center to 10% in Arp 220's nuclei, with the main uncertainty being the starbursts' magnetic field. We also model generic starbursts, including submillimeter galaxies, in the context of the FIR-X-ray relation, finding that anywhere between 0% and 16% of the total hard X-ray emission is synchrotron for different parameters, and up to 2% in the densest starbursts assuming an E {sup -2.2} injection spectrum and a diffusive escape time of 10 Myr (E/3 GeV){sup -1/2} (h/100 pc). Neutrino observations by IceCube and TeV {gamma}-ray data from HESS, VERITAS, and CTA can further constrain the synchrotron X-ray emission of starbursts. Our models do not constrain the possibility of hard, second components of primary e {sup {+-}} from sources like pulsars in starbursts, which could enhance the synchrotron X-ray emission further.

Lacki, Brian C. [Institute for Advanced Study, Princeton, NJ 08540 (United States)] [Institute for Advanced Study, Princeton, NJ 08540 (United States); Thompson, Todd A. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)] [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)

2013-01-01T23:59:59.000Z

82

Note: Experiments in hard x-ray chemistry: In situ production of molecular hydrogen and x-ray induced combustion  

Science Conference Proceedings (OSTI)

We have successfully loaded H{sub 2} into a diamond anvil cell at high pressure using the synchrotron x-ray induced decomposition of NH{sub 3}BH{sub 3}. In a second set of studies, radiation-assisted release of O{sub 2} from KCLO{sub 3}, H{sub 2} release from NH{sub 3}BH{sub 3}, and reaction of these gases in a mixture of the reactants to form liquid water using x-rays at ambient conditions was observed. Similar observations were made using a KCLO{sub 3} and NaBH{sub 4} mixture. Depending on reaction conditions, an explosive or far slower reaction producing water was observed.

Pravica, Michael; Bai Ligang; Liu Yu; Galley, Martin; Robinson, John [High Pressure Science and Engineering Center (HiPSEC) and Department of Physics, University of Nevada Las Vegas (UNLV), Las Vegas, Nevada 89154-4002 (United States); Park, Changyong [HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, 9700 South Cass Ave., Argonne, Illinois 60437 (United States); Hatchett, David [Department of Chemistry, University of Nevada Las Vegas (UNLV), Las Vegas, Nevada 89154-4003 (United States)

2012-03-15T23:59:59.000Z

83

Note: Experiments in hard x-ray chemistry: In situ production of molecular hydrogen and x-ray induced combustion  

DOE Green Energy (OSTI)

We have successfully loaded H{sub 2} into a diamond anvil cell at high pressure using the synchrotron x-ray induced decomposition of NH{sub 3}BH{sub 3}. In a second set of studies, radiation-assisted release of O{sub 2} from KCLO{sub 3}, H{sub 2} release from NH{sub 3}BH{sub 3}, and reaction of these gases in a mixture of the reactants to form liquid water using x-rays at ambient conditions was observed. Similar observations were made using a KCLO{sub 3} and NaBH{sub 4} mixture. Depending on reaction conditions, an explosive or far slower reaction producing water was observed.

Pravica, Michael; Bai, Ligang; Park, Changyong; Liu, Yu; Galley, Martin; Robinson, John; Hatchett, David (UNLV); (CIW)

2012-03-13T23:59:59.000Z

84

Phase-matched generation of coherent soft and hard X-rays using IR lasers  

DOE Patents (OSTI)

Phase-matched high-order harmonic generation of soft and hard X-rays is accomplished using infrared driving lasers in a high-pressure non-linear medium. The pressure of the non-linear medium is increased to multi-atmospheres and a mid-IR (or higher) laser device provides the driving pulse. Based on this scaling, also a general method for global optimization of the flux of phase-matched high-order harmonic generation at a desired wavelength is designed.

Popmintchev, Tenio V.; Chen, Ming-Chang; Bahabad, Alon; Murnane, Margaret M.; Kapteyn, Henry C.

2013-06-11T23:59:59.000Z

85

Hard x-ray response of a CdZnTe ring-drift detector  

Science Conference Proceedings (OSTI)

We present the results of an experimental study of a special type of CdZnTedetector of hard x and ? raysa ring-drift detector. The device consists of a double ring electrode structure surrounding a central point anode with a guard plane surrounding the outer anode ring. The detector can be operated in two distinctively different modes of charge collectionpseudohemispherical and pseudodrift. We study the detector response profiles obtained by scanning the focused x-ray beam over the whole detector area

A. Owens; R. den Hartog; F. Quarati; V. Gostilo; V. Kondratjev; A. Loupilov; A. G. Kozorezov; J. K. Wigmore; A. Webb; E. Welter

2007-01-01T23:59:59.000Z

86

A bi-prism interferometer for hard x-ray photons  

Science Conference Proceedings (OSTI)

Micro-fabricated bi-prisms have been used to create an interference pattern from an incident hard X-ray beam, and the intensity of the pattern probed with fluorescence from a 30 nm-thick metal film. Maximum fringe visibility exceeded 0.9 owing to the nano-sized probe and the choice of single-crystal prism material. A full near-field analysis is necessary to describe the fringe field intensities, and the transverse coherence lengths were extracted at APS beamline 8-ID-I. It is also shown that the maximum number of fringes is dependent only on the complex refractive index of the prism material.

Isakovic, A.F.; Siddons, D.; Stein, A.; Warren, J.B.; Sandy, A.R.; Narayanan, M.S.; Ablett, J.M.; Metzler, M. and Evans-Lutterodt, K.

2010-04-06T23:59:59.000Z

87

Transient pulsar dynamics in hard x-rays: Prognoz 9 and GRIF "Mir" space experiments data  

E-Print Network (OSTI)

The long-term observations of the Galactic Centre as well as the Galactic anti-Centre regions in hard X-rays (10-300 keV) were made in experiments on board Prognoz-9 satellite and "Mir" orbital station (GRIF experiment). Some transient pulsars including A0535+262, GS1722-36, 4U1145-619, A1118-615, EXO2030+37, Sct X-1, SAX J2103.5+4545, IGR 16320-4751, IGR 16465-4507 were observed. The pulsation flux components of A0535+26 and GS1722-36 X-ray emission were revealed at significant level. For other observed pulsars the upper limits of pulsation intensity were obtained. The mean pulsation profiles of A0535+26 in different energy ranges as well as the energy spectra were obtained at different stages of outburst decreasing. The pulsation intensity-period behavior does not contradict the well-known correlation between spin-up rate and X-ray flux, while the stable character of the energy spectrum power index indicates on the absence of thermal component. The energy spectrum and mean pulsation profiles were also obtained for one time interval of GS1722-36 observations. The upper limits of pulsation fluxes obtained for other observed transient pulsars at the orbital phases more than 0.14 correspond the quiescent state or final stage of the first type outburst.

M. I. Kudryavtsev; S. I. Svertilov; V. V. Bogomolov

2006-10-30T23:59:59.000Z

88

Application of an EMCCD Camera for Calibration of Hard X-Ray Telescopes  

SciTech Connect

Recent technological innovations now make it feasible to construct hard x-ray telescopes for space-based astronomical missions. Focusing optics are capable of improving the sensitivity in the energy range above 10 keV by orders of magnitude compared to previously used instruments. The last decade has seen focusing optics developed for balloon experiments and they will soon be implemented in approved space missions such as the Nuclear Spectroscopic Telescope Array (NuSTAR) and ASTRO-H. The full characterization of x-ray optics for astrophysical and solar imaging missions, including measurement of the point spread function (PSF) as well as scattering and reflectivity properties of substrate coatings, requires a very high spatial resolution, high sensitivity, photon counting and energy discriminating, large area detector. Novel back-thinned Electron Multiplying Charge-Coupled Devices (EMCCDs) are highly suitable detectors for ground-based calibrations. Their chip can be optically coupled to a microcolumnar CsI(Tl) scintillator via a fiberoptic taper. Not only does this device exhibit low noise and high spatial resolution inherent to CCDs, but the EMCCD is also able to handle high frame rates due to its controllable internal gain. Additionally, thick CsI(Tl) yields high detection efficiency for x-rays. This type of detector has already proven to be a unique device very suitable for calibrations in astrophysics: such a camera was used to support the characterization of the performance for all NuSTAR optics. Further optimization will enable similar cameras to be improved and used to calibrate x-ray telescopes for future space missions. In this paper, we discuss the advantages of using an EMCCD to calibrate hard x-ray optics. We will illustrate the promising features of this detector solution using examples of data obtained during the ground calibration of the NuSTAR telescopes performed at Columbia University during 2010/2011. Finally, we give an outlook on ongoing development and optimizations, such as the use of single photon counting mode to enhance spectral resolution.

Vogel, J K; Pivovaroff, M J; Nagarkar, V V; Kudrolli, H; Madsen, K K; Koglin, J E; Christensen, F E; Brejnholt, N F

2011-11-08T23:59:59.000Z

89

CO-ANALYSIS OF SOLAR MICROWAVE AND HARD X-RAY SPECTRAL EVOLUTIONS. I. IN TWO FREQUENCY OR ENERGY RANGES  

SciTech Connect

Solar microwave and hard X-ray spectral evolutions are co-analyzed in the 2000 June 10 and 2002 April 10 flares, and are simultaneously observed by the Owens-Valley Solar Array in the microwave band and by Yohkoh/Hard X-ray Telescope or RHESSI in the hard X-ray band, with multiple subpeaks in their light curves. The microwave and hard X-ray spectra are fitted by a power law in two frequency ranges of the optical thin part and two photon energy ranges, respectively. Similar to an earlier event in Shao and Huang, the well-known soft-hard-soft pattern of the lower energy range changed to the hard-soft-hard (HSH) pattern of the higher energy range during the spectral evolution of each subpeak in both hard X-ray flares. This energy dependence is actually supported by a positive correlation between the overall light curves and spectral evolution in the lower energy range, while it becomes an anti-correlation in the higher energy range. Regarding microwave data, the HSH pattern appears in the spectral evolution of each subpeak in the lower frequency range, which is somewhat similar to Huang and Nakajima. However, it returns back to the well-known pattern of soft-hard-harder for the overall spectral evolution in the higher frequency range of both events. This frequency dependence is confirmed by an anti-correlation between the overall light curves and spectral evolution in the lower frequency range, but it becomes a positive correlation in the higher frequency range. The possible mechanisms are discussed, respectively, for reasons why hard X-ray and microwave spectral evolutions have different patterns in different energy and frequency intervals.

Song Qiwu; Huang Guangli [Purple Mountain Observatory, Nanjing 210008 (China); Nakajima, Hiroshi, E-mail: songqw@pmo.ac.cng, E-mail: lhuang@pmo.ac.cn, E-mail: nakaji15@dia.janis.or.jp [Nobeyama Solar Radio Observatory, Nobeyama, Minamisaku, Nagano 384-1305 (Japan)

2011-06-20T23:59:59.000Z

90

Diagnostics of underwater electrical wire explosion through a time- and space-resolved hard x-ray source  

SciTech Connect

A time- and space-resolved hard x-ray source was developed as a diagnostic tool for imaging underwater exploding wires. A {approx}4 ns width pulse of hard x-rays with energies of up to 100 keV was obtained from the discharge in a vacuum diode consisting of point-shaped tungsten electrodes. To improve contrast and image quality, an external pulsed magnetic field produced by Helmholtz coils was used. High resolution x-ray images of an underwater exploding wire were obtained using a sensitive x-ray CCD detector, and were compared to optical fast framing images. Future developments and application of this diagnostic technique are discussed.

Sheftman, D.; Shafer, D.; Efimov, S.; Gruzinsky, K.; Gleizer, S.; Krasik, Ya. E. [Physics Department, Technion, Haifa 32000 (Israel)

2012-10-15T23:59:59.000Z

91

Compton polarimeters for the study of hard X-rays arising from energetic collisions of electrons and ions with matter  

Science Conference Proceedings (OSTI)

Novel position-sensitive x-ray detectors are presented that, when applied as Compton polarimeters, enable precise and efficient linear polarization studies of hard x-rays up to several 100 keV. We give an analytical formula which yields a rough estimate of the polarimeter efficiencies of such detector systems. Moreover, we briefly summarize a recent linear polarization measurement of the Lyman-{alpha}{sub 1} radiation in a H-like high-Z system, namely U91+.

Weber, G.; Braeuning, H.; Fritzsche, S.; Gumberidze, A.; Maertin, R.; Reuschl, R.; Schwemlein, M.; Spillmann, U.; Surzhykov, A.; Winters, D. F. A.; Stoehlker, Th. [Helmholtz-Institut Jena, Jena (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Jena, Jena (Germany)

2012-05-25T23:59:59.000Z

92

Neutron and hard x-ray measurements during pellet deposition in TFTR  

SciTech Connect

Measurements of neutrons and hard x rays are made with a pair of plastic scintillators during injection of deuterium pellets into deuterium TFTR plasmas. Three cases are investigated. During ohmic heating in plasmas with few runaway electrons, the neutron emission does not increase when a pellet is injected, indicating that strong acceleration of the pellet ions does not occur. In ohmic plasmas with low but detectable levels of runaway electrons, an x-ray burst is observed on a detector near the pellet injector as the pellet ablates, while a detector displaced 126/sup 0/ toroidally from the injector does not measure a synchronous burst. Reduced pellet penetration correlates with the presence of x-ray emission, suggesting that the origin of the burst is bremsstrahlung from runaway electrons that strike the solid pellet. In deuterium beam-heated discharges, an increase in the d-d neutron emission is observed when the pellet ablates. In this case, the increase is due to fusion reactions between beam ions and the high density neutral and plasma cloud produced by ablation of the pellet; this localized density perturbation equilibrates in about 700 ..mu..sec. Analysis of the data indicates that the density propagates without forming a sharp shock front with a rapid initial propagation velocity (greater than or equal to 2 x 10/sup 7/ cm/sec) that subsequently decreases to around 3 x 10/sup 6/ cm/sec. Modelling suggests that the electron heat flux into the pellet cloud is much less than the classical Spitzer value.

Heidbrink, W.W.; Milora, S.L.; Schmidt, G.L.; Schneider, W.; Ramsey, A.

1986-06-01T23:59:59.000Z

93

Fluctuation X-Ray Scattering  

SciTech Connect

The work supported by the grant was aimed at developing novel methods of finding the structures of biomolecules using x-rays from novel sources such as the x-ray free electron laser and modern synchrotrons

Saldin, PI: D. K.; Co-I's: J. C. H. Spence and P. Fromme

2013-01-25T23:59:59.000Z

94

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 crystal units (DCUs) to a full detector module (DM). We have built the first units of each component for the detector plane and have completed a few Rev2 DCUs (2x2 cm2), which are under a series of tests. Bare DCUs (pre-crystal bonding) show high, uniform ASIC yield (~70%) and ~30% reduction in electronics noise compared to the Rev1 equivalent. A Rev1 DCU already achieved ~1.2% FWHM at 662 keV, and preliminary analysis of the initial radiation tests on a Rev2 DCU shows ~ 4 keV FWHM at 60 keV (vs. 4.7 keV for Rev1). We therefore expect about <~1% FWHM at 662 keV with the Rev2 detectors.

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

2007-09-17T23:59:59.000Z

95

SUPERMODEL ANALYSIS OF THE HARD X-RAY EXCESS IN THE COMA CLUSTER  

SciTech Connect

The Supermodel (SM) provides an accurate description of the thermal contribution by the hot intracluster plasma which is crucial for the analysis of the hard excess. In this paper, the thermal emissivity in the Coma cluster is derived starting from the intracluster gas temperature and density profiles obtained by the SM analysis of X-ray observables: the XMM-Newton temperature profile and the ROSAT brightness distribution. The SM analysis of the BeppoSAX/Phoswich Detector System (PDS) hard X-ray (HXR) spectrum confirms our previous results, namely, an excess at the confidence level (c.l.) of {approx}4.8{sigma} and a nonthermal (NT) flux of (1.30 {+-} 0.40) x 10{sup -11} erg cm{sup -2} erg cm{sup -1} in the energy range 20-80 keV. A recent joint XMM-Newton/Suzaku analysis reports an upper limit of {approx}6 x 10{sup -12} erg cm{sup -2} erg cm{sup -1} in the energy range 20-80 keV for the NT flux with an average gas temperature of 8.45 {+-} 0.06 keV and an excess of NT radiation at a c.l. above 4{sigma}, without including systematic effects, for an average XMM-Newton temperature of 8.2 keV in the Suzaku/HXD-PIN FOV, in agreement with our earlier PDS analysis. Here we present a further evidence of the compatibility between the Suzaku and BeppoSAX spectra, obtained by our SM analysis of the PDS data, when the smaller size of the HXD-PIN FOV and the two different average temperatures derived by XMM-Newton and by the joint XMM-Newton/Suzaku analysis are taken into account. The consistency of the PDS and HXD-PIN spectra reaffirms the presence of an NT component in the HXR spectrum of the Coma cluster. The SM analysis of the PDS data reports an excess at c.l. above 4{sigma} also for the higher average temperature of 8.45 keV thanks to the PDS FOV being considerably greater than the HXD-PIN FOV.

Fusco-Femiano, R. [INAF/IASF-Roma, Via del Fosso del Cavaliere, I-00133 Roma (Italy); Orlandini, M. [INAF/IASF-BO, Via Gobetti 101, I-40129 Bologna (Italy); Bonamente, M. [Department of Physics, University of Alabama, Huntsville, AL 35899 (United States); Lapi, A. [Dipartimento di Fisica, Universita 'Tor Vergata', Via Ricerca Scientifica 1, I-00133 Roma (Italy)

2011-05-10T23:59:59.000Z

96

Multipixel characterization of imaging CZT detectors for hard X-ray imaging and spectroscopy  

E-Print Network (OSTI)

We report our in-depth study of Cd-Zn-Te (CZT) crystals to determine an optimum pixel and guard band configuration for Hard X-ray imaging and spectroscopy. We tested 20x20x5mm crystals with 8x8 pixels on a 2.46mm pitch. We have studied different types of cathode / anode contacts and different pixel pad sizes. We present the measurements of leakage current as well as spectral response for each pixel. Our I-V measurement setup is custom designed to allow automated measurements of the I-V curves sequentially for all 64 pixels, whereas the radiation properties measurement setup allows for interchangeable crystals with the same XAIM3.2 ASIC readout from IDEAS. We have tested multiple crystals of each type, and each crystal in different positions to measure the variation between individual crystals and variation among the ASIC channels. We also compare the same crystals with and without a grounded guard band deposited on the crystal side walls vs. a floating guard band and compare results to simulations. This study was carried out to find the optimum CZT crystal configuration for prototype detectors for the proposed Black-Hole Finder mission, EXIST.

S. V. Vadawale; J. Hong; J. Grindlay; P. Williams; M. Zhang; E. Bellm; T. Narita; W. Craig; B. Parker; C. Stahle; Feng Yan

2004-09-03T23:59:59.000Z

97

The potential for extending the spectral range accessible to the european X-ray free electron laser in the direction of longer wavelengths  

E-Print Network (OSTI)

The baseline specifications of European XFEL give a range of wavelengths between 0.1 nm and 2 nm. This wavelength range at fixed electron beam energy 17.5 GeV can be covered by operating the SASE FEL with three undulators which have different period and tunable gap. A study of the potential for the extending the spectral range accessible to the XFEL in the direction of longer wavelengths is presented. The extension of the wavelength range to 6 nm would be cover the water window in the VUV region, opening the facility to a new class of experiments. There are at least two possible sources of VUV radiation associated with the X-ray FEL; the "low (2.5 GeV) energy electron beam dedicated" and the " 17.5 GeV spent beam parasitic" (or "after-burner") source modes. The second alternative, "after-burner undulator" is the one we regard as most favorable. It is possible to place an undulator as long as 80 meters after 2 nm undulator. Ultimately, VUV undulator would be able to deliver output power approaching 100 GW. A b...

Saldin, E L; Yurkov, M V

2004-01-01T23:59:59.000Z

98

SSRL School 2008 on Hard X-ray Scattering Techniques in MES  

NLE Websites -- All DOE Office Websites (Extended Search)

May 20-22, 2008 SSRL School on Synchrotron X-ray Absorption Spectroscopy Techniques in Environmental and Materials Sciences: Theory and Application Group photo from the 2008 SSRL...

99

Development of mirror manipulator for hard-x-ray nanofocusing at sub-50-nm level  

Science Conference Proceedings (OSTI)

X-ray focusing using Kirkpatrick-Baez (KB) mirrors is promising owing to their capability of highly efficient and energy-tunable focusing. We report the development of a mirror manipulator which enables KB mirror alignment with a high degree of accuracy. Mirror alignment tolerances were estimated using two types of simulators. On the basis of the simulation results, the mirror manipulator was developed to achieve an optimum KB mirror setup. As a result of focusing tests at BL29XUL of SPring-8, the beam size of 48x36 nm{sup 2} (VxH) was achieved in the full width at half maximum at an x-ray energy of 15 keV. Spatial resolution tests showed that a scanning x-ray microscope equipped with the KB focusing system could resolve line-and-space patterns of 80 nm linewidth in a high visibility of 60%.

Matsuyama, S.; Mimura, H.; Yumoto, H.; Hara, H.; Yamamura, K.; Sano, Y.; Endo, K.; Mori, Y.; Yabashi, M.; Nishino, Y.; Tamasaku, K.; Ishikawa, T.; Yamauchi, K. [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Research Center for Ultra-Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Research Center for Ultra-Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); SPring-8/Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Mikazuki, Hyogo 679-5148 (Japan); SPring-8/RIKEN, 1-1-1 Kouto, Mikazuki, Hyogo 679-5148 (Japan); Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2006-09-15T23:59:59.000Z

100

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

SciTech Connect

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

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101

NUMERICAL SIMULATIONS OF CHROMOSPHERIC HARD X-RAY SOURCE SIZES IN SOLAR FLARES  

Science Conference Proceedings (OSTI)

X-ray observations are a powerful diagnostic tool for transport, acceleration, and heating of electrons in solar flares. Height and size measurements of X-ray footpoint sources can be used to determine the chromospheric density and constrain the parameters of magnetic field convergence and electron pitch-angle evolution. We investigate the influence of the chromospheric density, magnetic mirroring, and collisional pitch-angle scattering on the size of X-ray sources. The time-independent Fokker-Planck equation for electron transport is solved numerically and analytically to find the electron distribution as a function of height above the photosphere. From this distribution, the expected X-ray flux as a function of height, its peak height, and full width at half-maximum are calculated and compared with RHESSI observations. A purely instrumental explanation for the observed source size was ruled out by using simulated RHESSI images. We find that magnetic mirroring and collisional pitch-angle scattering tend to change the electron flux such that electrons are stopped higher in the atmosphere compared with the simple case with collisional energy loss only. However, the resulting X-ray flux is dominated by the density structure in the chromosphere and only marginal increases in source width are found. Very high loop densities (>10{sup 11} cm{sup -3}) could explain the observed sizes at higher energies, but are unrealistic and would result in no footpoint emission below about 40 keV, contrary to observations. We conclude that within a monolithic density model the vertical sizes are given mostly by the density scale height and are predicted smaller than the RHESSI results show.

Battaglia, M.; Kontar, E. P.; Fletcher, L.; MacKinnon, A. L., E-mail: marina.battaglia@fhnw.ch [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2012-06-10T23:59:59.000Z

102

INTEGRAL spectral variability study of the atoll 4U 1820-30: first detection of hard X-ray emission  

E-Print Network (OSTI)

We study the 4-200 keV spectral and temporal behaviour of the low mass X-ray binary 4U 1820-30 with INTEGRAL during 2003-2005. This source as been observed in both the soft (banana) and hard (island) spectral states. A high energy tail, above 50 keV, in the hard state has been observed for the first time. This places the source in the category of X-ray bursters showing high-energy emission. The tail can be modeled as a soft power law component, with the photon index of ~2.4, on top of thermal Comptonization emission from a plasma with the electron temperature of kT_e~6 keV and optical depth of \\tau~4. Alternatively, but at a lower goodness of the fit, the hard-state broad band spectrum can be accounted for by emission from a hybrid, thermal-nonthermal, plasma. During this monitoring the source spent most of the time in the soft state, usual for this source, and the >~4 keV spectra are represented by thermal Comptonization with kT_e~3 keV and \\tau~6-7.

Antonella Tarana; Angela Bazzano; Pietro Ubertini; Andrzej A. Zdziarski

2006-08-28T23:59:59.000Z

103

THE RELATIONSHIP BETWEEN HARD X-RAY PULSE TIMINGS AND THE LOCATIONS OF FOOTPOINT SOURCES DURING SOLAR FLARES  

SciTech Connect

The cause of quasi-periodic pulsations in solar flares remains the subject of debate. Recently, Nakariakov and Zimovets proposed a new model suggesting that, in two-ribbon flares, such pulsations could be explained by propagating slow waves. These waves may travel obliquely to the magnetic field, reflect in the chromosphere, and constructively interfere at a spatially separate site in the corona, leading to quasi-periodic reconnection events progressing along the flaring arcade. Such a slow wave regime would have certain observational characteristics. We search for evidence of this phenomenon during a selection of two-ribbon flares observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager, Solar and Heliospheric Observatory, and Transition Region and Coronal Explorer; the flares of 2002 November 9, 2005 January 19, and 2005 August 22. We were not able to observe a clear correlation between hard X-ray footpoint separations and pulse timings during these events. Also, the motion of hard X-ray footpoints is shown to be continuous within the observational error, whereas a discontinuous motion might be anticipated in the slow wave model. Finally, we find that for a preferential slow wave propagation angle of 25 Degree-Sign -28 Degree-Sign that is expected for the fastest waves, the velocities of the hard X-ray footpoints lead to estimated pulse periods and ribbon lengths significantly larger than the measured values. Hence, for the three events studied, we conclude that the observational characteristics cannot be easily explained via the Nakariakov and Zimovets propagating slow wave model when only angles of 25 Degree-Sign -28 Degree-Sign are considered. We provide suggested flare parameters to optimize future studies of this kind.

Inglis, A. R.; Dennis, B. R. [Solar Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-04-01T23:59:59.000Z

104

Analysis and Interpretation of Hard X-ray Emission fromthe Bullet Cluster (1E0657-56), the Most Distant Cluster of Galaxies Observed by the RXTE  

Science Conference Proceedings (OSTI)

Evidence for non-thermal activity in clusters of galaxies is well established from radio observations of synchrotron emission by relativistic electrons. New windows in the Extreme Ultraviolet and Hard X-ray ranges have provided for more powerful tools for the investigation of this phenomenon. Detection of hard X-rays in the 20 to 100 keV range have been reported from several clusters of galaxies, notably from Coma and others. Based on these earlier observations we identified the relatively high redshift cluster 1E0657-56 (also known as RX J0658-5557) as a good candidate for hard X-ray observations. This cluster, also known as the bullet cluster, has many other interesting and unusual features, most notably that it is undergoing a merger, clearly visible in the X-ray images. Here we present results from a successful RXTE observations of this cluster. We summarize past observations and their theoretical interpretation which guided us in the selection process. We describe the new observations and present the constraints we can set on the flux and spectrum of the hard X-rays. Finally we discuss the constraints one can set on the characteristics of accelerated electrons which produce the hard X-rays and the radio radiation.

Petrosian, Vahe; /Stanford U., Phys. Dept. /SLAC /Stanford U., Appl. Phys. Dept.; Madejski, Greg; /SLAC; Luli, Kevin; /Stanford U., Phys. Dept.

2006-08-16T23:59:59.000Z

105

Frontiers in X-Ray Science  

Science Conference Proceedings (OSTI)

The year 2010 marked the fiftieth anniversary of the optical laser and the first anniversary of the world's first hard x-ray free-electron laser, the Linac Coherent Light Source (LCLS) at SLAC. This exciting, new accelerator-based source of x-rays provides peak brilliances roughly a billion times greater than currently available from synchrotron sources such as the Advanced Photon Source at Argonne, and thus explores a qualitatively different parameter space. This talk will describe the first experiments at the LCLS aimed at understanding the nature of high intensity x-ray interactions, related applications in ultrafast imaging on the atomic scale and sketch nascent plans for the extension of both linac and storage-ring based photon sources.

Linda Young

2011-02-23T23:59:59.000Z

106

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

107

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

Science Conference Proceedings (OSTI)

Commonly, SOFCs are operated at high temperatures (above 800C). 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

108

Harmonic Generation at Lower Electron Energies for a Hard X-ray FEL  

SciTech Connect

There are several schemes currently being investigated to pre-bunch the electron beam and step the coherent bunching up to higher harmonics, all which require modulator sections which introduce additional energy modulation. X-ray FELs operate in a regime where the FEL parameter, {rho} is equal to or less than the effective energy spread introduced from the emittance in the electron beam. Because of this large effective energy spread, the energy modulation introduced from harmonic generation schemes would seriously degrade FEL performance. This problem can be mitigated by incorporating the harmonic generation scheme at a lower electron kinetic energy than the energy at the final undulator. This will help because the effective energy spread from emittance is reduced at lower energies, and can be further reduced by making the beam transversely large. Then the beam can be squeezed down slowly enough in the subsequent accelerator sections so that geometric debunching is mitigated. The beam size inside the dispersive chicanes and in the accelerator sections must be carefully optimized to avoid debunching, and each subharmonic modulator section must generate enough energy modulation to overcome the SASE noise without significantly increasing the gain length in the final undulator. Here we show analytical results that demonstrate the feasibility of this harmonic pre-bunching scheme.

Marksteiner, Quinn R. [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

109

Annealing dependence of diamond-metal Schottky barrier heights probed by hard x-ray photoelectron spectroscopy  

SciTech Connect

Hard x-ray photoelectron spectroscopy was applied to investigate the diamond-metal Schottky barrier heights for several metals and diamond surface terminations. The position of the diamond valence-band maximum was determined by theoretically calculating the diamond density of states and applying cross section corrections. The diamond-platinum Schottky barrier height was lowered by 0.2 eV after thermal annealing, indicating annealing may increase carrier injection in diamond devices leading to photoconductive gain. The platinum contacts on oxygen-terminated diamond was found to provide a higher Schottky barrier and therefore a better blocking contact than that of the silver contact in diamond-based electronic devices.

Gaowei, M.; Muller, E. M. [Department of Materials Science and Engineering, SUNY Stony Brook, Stony Brook, New York 11794 (United States); Rumaiz, A. K. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States); Weiland, C.; Cockayne, E.; Woicik, J. C. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Jordan-Sweet, J. [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Smedley, J. [Instrumentation Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2012-05-14T23:59:59.000Z

110

THE ROLE OF INVERSE COMPTON SCATTERING IN SOLAR CORONAL HARD X-RAY AND {gamma}-RAY SOURCES  

SciTech Connect

Coronal hard X-ray (HXR) and continuum {gamma}-ray sources associated with the impulsive phase of solar flares have been the subject of renewed interest in recent years. They have been interpreted in terms of thin-target, non-thermal bremsstrahlung emission. This interpretation has led to rather extreme physical requirements in some cases. For example, in one case, essentially all of the electrons in the source must be accelerated to non-thermal energies to account for the coronal HXR source. In other cases, the extremely hard photon spectra of the coronal continuum {gamma}-ray emission suggest that the low-energy cutoff of the electron energy distribution lies in the MeV energy range. Here, we consider the role of inverse Compton scattering (ICS) as an alternate emission mechanism in both the ultra- and mildly relativistic regimes. It is known that relativistic electrons are produced during powerful flares; these are capable of upscattering soft photospheric photons to HXR and {gamma}-ray energies. Previously overlooked is the fact that mildly relativistic electrons, generally produced in much greater numbers in flares of all sizes, can upscatter extreme-ultraviolet/soft X-ray photons to HXR energies. We also explore ICS on anisotropic electron distributions and show that the resulting emission can be significantly enhanced over an isotropic electron distribution for favorable viewing geometries. We briefly review results from bremsstrahlung emission and reconsider circumstances under which non-thermal bremsstrahlung or ICS would be favored. Finally, we consider a selection of coronal HXR and {gamma}-ray events and find that in some cases the ICS is a viable alternative emission mechanism.

Chen Bin [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Bastian, T. S. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)

2012-05-01T23:59:59.000Z

111

Hard Extended X-ray Source in the IC 443 SNR Resolved by Chandra: A Fast Ejecta Fragment or a New Pulsar Wind Nebula?  

E-Print Network (OSTI)

A Chandra observation of the isolated hard X-ray source XMMU J061804.3+222732, located in the region of apparent interaction of the supernova remnant IC 443 with a molecular cloud, resolved the complex structure of the source in a few bright clumps embedded in an extended emission of a ~ 30 arcsec size. The X-ray spectra of the clumps and the extended emission are dominated by a hard power-law component with a photon index of 1.2--1.4. In addition, we see some indications of an optically thin thermal plasma of a ~ 0.3 keV temperature. The observed X-ray morphology and spectra are consistent with those expected for an isolated supernova ejecta fragment interacting with a dense ambient medium. A possible alternative interpretation is a pulsar wind nebula associated with either IC 443 or another SNR, G189.6+3.3.

A. M. Bykov; F. Bocchino; G. G. Pavlov

2005-03-31T23:59:59.000Z

112

Hard Extended X-ray Source in the IC 443 SNR Resolved by Chandra: A Fast Ejecta Fragment or a New Pulsar Wind Nebula?  

E-Print Network (OSTI)

A Chandra observation of the isolated hard X-ray source XMMU J061804.3+222732, located in the region of apparent interaction of the supernova remnant IC 443 with a molecular cloud, resolved the complex structure of the source in a few bright clumps embedded in an extended emission of a ~ 30 arcsec size. The X-ray spectra of the clumps and the extended emission are dominated by a hard power-law component with a photon index of 1.2--1.4. In addition, we see some indications of an optically thin thermal plasma of a ~ 0.3 keV temperature. The observed X-ray morphology and spectra are consistent with those expected for an isolated supernova ejecta fragment interacting with a dense ambient medium. A possible alternative interpretation is a pulsar wind nebula associated with either IC 443 or another SNR, G189.6+3.3.

Bykov, A M; Pavlov, G G

2005-01-01T23:59:59.000Z

113

Rapid optical and X-ray timing observations of GX 339-4: flux correlations at the onset of a low/hard state  

E-Print Network (OSTI)

We present the discovery of optical/X-ray flux correlations on rapid timescales in the low/hard state of the Galactic black hole GX 339-4. The source had recently emerged from outburst and was associated with a relatively-faint counterpart with mag V~17. The optical (VLT/ULTRACAM) and X-ray (RXTE/PCA) data show a clear positive cross-correlation function (CCF) signal, with the optical peak lagging X-rays by ~ 150 ms, preceded by a shallow rise and followed by a steep decline along with broad anti-correlation dips. Examination of the light curves shows that the main CCF features are reproduced in superpositions of flares and dips. The CCF peak is narrow and the X-ray auto-correlation function (ACF) is broader than the optical ACF, arguing against reprocessing as the origin for the rapid optical emission. X-ray flaring is associated with spectral hardening, but no corresponding changes are detected around optical peaks and dips. The variability may be explained in the context of synchrotron emission with interaction between a jet and a corona. The complex CCF structure in GX 339-4 has similarities to that of another remarkable X-ray binary XTE J1118+480, in spite of showing a weaker maximum strength. Such simultaneous multi-wavelength, rapid timing studies provide key constraints for modeling the inner regions of accreting stellar sources.

P. Gandhi; K. Makishima; M. Durant; A. C. Fabian; V. S. Dhillon; T. R. Marsh; J. M. Miller; T. Shahbaz; H. C. Spruit

2008-07-09T23:59:59.000Z

114

Fermi acceleration at fast shock in a solar flare and impulsive loop-top hard X-ray source  

E-Print Network (OSTI)

We propose that non-thermal electrons are efficiently accelerated by first-order Fermi process at the fast shock, as a natural consequence of the new magnetohydrodynamic picture of the flaring region revealed with Yohkoh. An oblique fast shock is naturally formed below the reconnection site, and boosts the acceleration to significantly decrease the injection energy. The slow shocks attached to the reconnection X-point heat the plasma up to 10--20 MK, exceeding the injection energy. The combination of the oblique shock configuration and the pre-heating by the slow shock allows bulk electron acceleration from the thermal pool. The accelerated electrons are trapped between the two slow shocks due to the magnetic mirror downstream of the fast shock, thus explaining the impulsive loop-top hard X-ray source discovered with Yohkoh. Acceleration time scale is ~ 0.3--0.6 s, which is consistent with the time scale of impulsive bursts. When these electrons stream away from the region enclosed by the fast shock and the s...

Tsuneta, S; Tsuneta, Saku; Naito, Tsuguya

1998-01-01T23:59:59.000Z

115

The Role of Inverse Compton Scattering in Solar Coronal Hard X-ray and Gamma-ray Sources  

E-Print Network (OSTI)

We consider the role of inverse Compton scattering (ICS) as a means of producing coronal hard X-ray (HXR) and continuum gamma-ray sources during solar flares. Coronal HXR and continuum gamma-ray emission observed during solar flares has been interpreted in terms of thin-target bremsstrahlung emission. In one case, this interpretation leads to the conclusion that the number of energetic electrons required to account for the coronal HXR source must be large, implying that essentially all electrons in the source must be accelerated to energies >~ 16 keV. In other cases, the spectral index of the photon spectrum of gamma-ray sources approaches the theoretical limit for bremsstrahlung emission (alpha ~ 1.5 - 2). Here we investigate ICS in both the fully relativistic and mildly relativistic regimes as an alternative to non-thermal bremsstrahlung. It is known that relativistic electrons are produced during powerful flares; these are capable of up-scattering soft photospheric photons to HXR energies. Previously overl...

Chen, Bin

2011-01-01T23:59:59.000Z

116

BAYESIAN CONFIDENCE LIMITS OF ELECTRON SPECTRA OBTAINED THROUGH REGULARIZED INVERSION OF SOLAR HARD X-RAY SPECTRA  

SciTech Connect

Many astrophysical observations are characterized by a single, non-repeatable measurement of a source brightness or intensity, from which we are to construct estimates for the true intensity and its uncertainty. For example, the hard X-ray count spectrum from transient events such as solar flares can be observed only once, and from this single spectrum one must determine the best estimate of the underlying source spectrum I({epsilon}), and hence the form of the responsible electron spectrum F(E). Including statistical uncertainties on the measured count spectrum yields a 'confidence strip' that delineates the boundaries of electron spectra that are consistent with the observed photon spectrum. In this short article, we point out that the expectation values of the source brightness and its variance in a given photon energy bin are in general not (as has been assumed in prior works) equal to n, the number of counts observed in that energy bin. Rather, they depend both on n and on prior knowledge of the overall photon spectrum. Using Bayesian statistics, we provide an explicit procedure and formulas for determining the 'confidence strip' (Bayesian credible region) for F(E), thus providing rigorous bounds on the intensity and shape of the accelerated electron spectrum.

Emslie, A. Gordon [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY 42101 (United States); Massone, Anna Maria, E-mail: emslieg@wku.edu, E-mail: annamaria.massone@cnr.it [CNR-SPIN, Via Dodecaneso 33, I-16146 Genova (Italy)

2012-11-10T23:59:59.000Z

117

IMPULSIVE PHASE CORONAL HARD X-RAY SOURCES IN AN X3.9 CLASS SOLAR FLARE  

SciTech Connect

We present the analysis of a pair of unusually energetic coronal hard X-ray (HXR) sources detected by the Reuven Ramaty High Energy Solar Spectroscopic Imager during the impulsive phase of an X3.9 class solar flare on 2003 November 3, which simultaneously shows two intense footpoint (FP) sources. A distinct loop top (LT) coronal source is detected up to {approx}150 keV and a second (upper) coronal source up to {approx}80 keV. These photon energies, which were not fully investigated in earlier analysis of this flare, are much higher than commonly observed in coronal sources and pose grave modeling challenges. The LT source in general appears higher in altitude with increasing energy and exhibits a more limited motion compared to the expansion of the thermal loop. The high-energy LT source shows an impulsive time profile and its nonthermal power-law spectrum exhibits soft-hard-soft evolution during the impulsive phase, similar to the FP sources. The upper coronal source exhibits an opposite spatial gradient and a similar spectral slope compared to the LT source. These properties are consistent with the model of stochastic acceleration of electrons by plasma waves or turbulence. However, the LT and FP spectral index difference (varying from {approx}0 to 1) is much smaller than commonly measured and than that expected from a simple stochastic acceleration model. Additional confinement or trapping mechanisms of high-energy electrons in the corona are required. Comprehensive modeling including both kinetic effects and the macroscopic flare structure may shed light on this behavior. These results highlight the importance of imaging spectroscopic observations of the LT and FP sources up to high energies in understanding electron acceleration in solar flares. Finally, we show that the electrons producing the upper coronal HXR source may very likely be responsible for the type III radio bursts at the decimetric/metric wavelength observed during the impulsive phase of this flare.

Chen Qingrong; Petrosian, Vahe, E-mail: qrchen@gmail.com, E-mail: vahep@stanford.edu [Department of Physics and KIPAC, Stanford University, Stanford, CA 94305 (United States)

2012-03-20T23:59:59.000Z

118

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

Science Conference Proceedings (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

119

Band alignment of InGaZnO{sub 4}/Si interface by hard x-ray photoelectron spectroscopy  

SciTech Connect

Although amorphous InGaZnO{sub 4} has intensively been studied for a semiconductor channel material of thin-film transistors in next-generation flat-panel displays, its electronic structure parameters have not been reported. In this work, the electron affinities ({chi}) and the ionization potentials (I{sub p}) of crystalline and amorphous InGaZnO{sub 4} (c-IGZO and a-IGZO) were measured using bulk-sensitive hard x-ray photoelectron spectroscopy. First, the {chi} and I{sub p} values of c-IGZO and a-IGZO thin films were estimated by aligning the Zn 2p{sub 3/2} core level energies to a literature value for ZnO, which provided {chi} = 3.90 eV and I{sub p} = 7.58 eV for c-IGZO and 4.31 eV and 7.41 eV for a-IGZO. It was also confirmed that the escape depth of the photoelectrons excited by the photon energy of 5950.2 eV is 3.3 nm for a-IGZO and large enough for directly measuring the interface electronic structure using a-IGZO/c-Si heterojunctions. It provided the valence band offset of {approx}2.3 eV, which agrees well with the above data. The present results substantiate that the a-IGZO/c-Si interface follows well the Schottky-Mott rule.

Lee, Kyeongmi; Kamiya, Toshio [Materials and Structures Laboratory, Tokyo Institute of Technology, Mailbox R3-1, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Nomura, Kenji [Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Yanagi, Hiroshi [Interdisciplinary Graduate School of Medical and Engineering Material Science and Technology, University of Yamanashi, 4-4-37 Takeda, Kofu, Yamanashi 400-8510 (Japan); Ikenaga, Eiji; Sugiyama, Takeharu [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan); Kobayashi, Keisuke [National Institute for Materials Science, SPring-8, Hyogo 679-5148 (Japan); Hosono, Hideo [Materials and Structures Laboratory, Tokyo Institute of Technology, Mailbox R3-1, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

2012-08-01T23:59:59.000Z

120

Earth Occultation Imaging Applied to BATSE -- Application to a Combined BATSE-GBM Survey of the Hard X-Ray Sky  

E-Print Network (OSTI)

A combined BATSE-GBM hard X-ray catalog is presented based on Earth Occultation Imaging applied to a reanalysis of BATSE data. An imaging approach has been developed for the reanalysis of Earth Occultation analysis of BATSE data. The standard occultation analysis depends on a predetermined catalog of potential sources, so that a real source not present in the catalog may induce systematic errors when source counts associated with an uncatalogued source are incorrectly attributed to catalog sources. The goal of the imaging analysis is to find a complete set of hard X-ray sources, including sources not in the original BATSE occultation catalog. Using the imaging technique, we have identified 15 known sources and 17 unidentified sources and added them to the BATSE occultation catalog. The resulting expanded BATSE catalog of sources observed during 1991-2000 is compared to the ongoing GBM survey.

Zhang, Yuan; Case, Gary; Ling, James; Wheaton, William

2013-01-01T23:59:59.000Z

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121

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

Science Conference Proceedings (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

122

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

Science Conference Proceedings (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

123

Fifth-Generation Free-Electron Laser Light Sources  

SciTech Connect

During the past few years, the Linac Coherent Light Source (LCLS) and the Free-Electron Laser in Hamburg (FLASH) have demonstrated the outstanding capability of free-electron lasers (FELs) as sources of coherent radiation in the soft and hard x-ray region. The high intensity, tens of GW, short pulses (few to less than 100 femtoseconds, and the unique transverse coherence properties are opening a new window to study the structure and dynamics of atomic and molecular systems. The LCLS, FLASH, and the other FELs now under construction are only the beginning of the development of these light sources. The next generations will reach new levels of performance: terawatt, atto-second, ultra-small line-width, high repetition rate, full longitudinal and transverse coherence. These future developments and the R&D needed to successfully build and operate the next generation of FEL light sources will be discussed.

Pellegrini, Claudio [UCLA

2011-03-02T23:59:59.000Z

124

Flight Performance of an advanced CZT Imaging Detector in a Balloon-borne Wide-Field Hard X-ray Telescope - ProtoEXIST1  

E-Print Network (OSTI)

We successfully carried out the first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1, which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009. ProtoEXIST1 is the first implementation of an advanced CdZnTe (CZT) imaging detector in our ongoing program to establish the technology required for next generation wide-field hard X-ray telescopes. The CZT detector plane in ProtoEXIST1 consists of an 8 x 8 array of closely tiled 2 cm x 2 cm x 0.5 cm thick pixellated CZT crystals, each with 8 x 8 pixels, covering a 256 cm^2 active area with 2.5 mm pixels. A tungsten mask, mounted at 90 cm above the detector provides shadowgrams of X-ray sources in the 30 - 600 keV band for imaging, allowing a fully coded field of view of 9 Deg x 9 Deg with an angular resolution of 20 arcmin. To reduce the background radiation, the detector is surrounded by semi-graded (Pb/Sn/Cu) passive shields on the four sides all the way to the mask. ...

Hong, J; Grindlay, J; Barthelemy, S; Baker, R; Garson, A; Krawczynski, H; Apple, J; Cleveland, W H

2011-01-01T23:59:59.000Z

125

A uniformly redundant imaging array of penumbral apertures coupled with a heuristic reconstruction for hard x-ray and neutron imaging  

SciTech Connect

A coded imaging and decoding (image reconstruction) scheme was developed for diagnosing a hot and dense region emitting hard x-rays and neutrons in laser-fusion plasmas. Because the imager was a uniformly redundant array of penumbral aperture (URPA) arranged in an M-matrix, URPA leads to N times (N: the total number of apertures) enhancement of signal intensity in comparison with a single penumbral aperture. A recorded penumbral image was reconstructed by a computer-based heuristic method to reduce artifacts caused by noises contained in a penumbral image. Applicability of this technique was investigated by imaging x-rays emitted from laser-produced plasmas, demonstrating a spatial resolution of 16 {mu}m. Under the present conditions, the spatial resolution was determined dominantly by a detector resolution (10.5 {mu}m) and a signal-to-noise ratio of the obtained penumbral image.

Ueda, Tatsuki; Fujioka, Shinsuke; Nishimura, Hiroaki [Institute of Laser Engineering, Osaka University, 2-6, Yamada-oka, Suita, Osaka, 565-0871 (Japan); Nozaki, Shinya; Azuma, Rumiko [Transdisplinary Research Organization for Subtropics Island Studies, University of the Ryukyus, 1 Senbaru Nishihara, Okinawa, 903-0213 (Japan); Chen, Yen-Wei [College of Information Science and Engineering, Ritsumeikan University, 1-1-1 Nojihigasi Kusatsu, Shiga, 525-8577 (Japan)

2010-07-15T23:59:59.000Z

126

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

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

127

FREE ELECTRON LASERS  

E-Print Network (OSTI)

1984). Colson, W. B. , "Free electron laser theory," Ph.D.M. 0. , Spitzer, R. , editors, Free Electron Generators ofM.D. , Spitzer, R. , editors, Free Electron Generators of

Colson, W.B.

2008-01-01T23:59:59.000Z

128

Free Electron Laser  

NLE Websites -- All DOE Office Websites (Extended Search)

Free Electron Laser Building Exterior Top Floor Control Room RF Gallery User Lab Beam Enclosure Injector Linear Accelerator Wiggler Magnet Return Line Free Electron Laser Most...

129

A multi-crystal wavelength dispersive x-ray spectrometer  

Science Conference Proceedings (OSTI)

A multi-crystal wavelength dispersive hard x-ray spectrometer with high-energy resolution and large solid angle collection is described. The instrument is specifically designed for time-resolved applications of x-ray emission spectroscopy (XES) and x-ray Raman scattering (XRS) at X-ray Free Electron Lasers (XFEL) and synchrotron radiation facilities. It also simplifies resonant inelastic x-ray scattering (RIXS) studies of the whole 2d RIXS plane. The spectrometer is based on the Von Hamos geometry. This dispersive setup enables an XES or XRS spectrum to be measured in a single-shot mode, overcoming the scanning needs of the Rowland circle spectrometers. In conjunction with the XFEL temporal profile and high-flux, it is a powerful tool for studying the dynamics of time-dependent systems. Photo-induced processes and fast catalytic reaction kinetics, ranging from femtoseconds to milliseconds, will be resolvable in a wide array of systems circumventing radiation damage.

Alonso-Mori, Roberto; Montanez, Paul; Delor, James; Bergmann, Uwe [LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Kern, Jan [LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-8099 (United States); Sokaras, Dimosthenis; Weng, Tsu-Chien; Nordlund, Dennis [SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Tran, Rosalie; Yachandra, Vittal K.; Yano, Junko [Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-8099 (United States)

2012-07-15T23:59:59.000Z

130

FREE-ELECTRON LASERS  

SciTech Connect

We can now produce intense, coherent light at wavelengths where no conventional lasers exist. The recent successes of devices known as free-electron lasers mark a striking confluence of two conceptual developments that themselves are only a few decades old. The first of these, the laser, is a product of the fifties and sixties whose essential characteristics have made it a staple resource in almost every field of science and technology. In a practical sense, what defines a laser is its emission of monochromatic, coherent light (that is, light of a single wavelength, with its waves locked in step) at a wavelength in the infrared, visible, or ultraviolet region of the electromagnetic spectrum. A second kind of light, called synchrotron radiation, is a by-product of the age of particle accelerators and was first observed in the laboratory in 1947. As the energies of accelerators grew in the 1960s and 70s, intense, incoherent beams of ultraviolet radiation and x--rays became available at machines built for high-energy physics research. Today, several facilities operate solely as sources of synchrotron light. Unlike the well-collimated monochromatic light emitted by lasers, however, this incoherent radiation is like a sweeping searchlight--more accurately, like the headlight of a train on a circular track--whose wavelengths encompass a wide spectral band. Now, in several laboratories around the world, researchers have exploited the physics of these two light sources and have combined the virtues of both in a single contrivance, the free-electron laser, or FEL (1). The emitted light is laserlike in its narrow, sharply peaked spectral distribution and in its phase coherence, yet it can be of a wavelength unavailable with ordinary lasers. Furthermore, like synchrotron radiation, but unlike the output of most conventional lasers, the radiation emitted by free-electron lasers can be tuned, that is, its wavelength can be easily varied across a wide range. The promise of this new technology extends from the fields of solid-state physics, gas- and liquid-phase photochemistry, and surface catalysis to futuristic schemes for ultrahigh-energy linear accelerators.

Sessler, A.M.; Vaughan, D.

1986-04-01T23:59:59.000Z

131

High-resolution spectroscopic diagnostics of very high-temperature plasmas in the hard x-ray regime  

SciTech Connect

Motivated by the need for establishing a reliable database useful for the application of x-ray spectroscopic tools for the diagnostic of very high temperature plasmas, high-resolution crystal spectrometer measurements have been performed investigating the characteristic K-shell radiation of highly charged krypton and xenon. The measurements, which have been performed at the Electron-Beam-Ion-Trap (EBIT) facility of the Lawrence Livermore National Laboratory, include the investigation of the n = 2 {yields} 1 transitions in heliumlike krypton (Kr{sup 34+}) and innershell excited lithiumlike krypton (Kr{sup 33+}) utilizing a conventional reflection-type crystal spectrometer of von Hamos geometry. The electron-excitation-energy selective measurements map the contribution of the dielectronic recombination lines providing the means of accurate interpretation of the line profiles of the characteristic K{alpha} x-ray emission of plasmas. The high-resolution measurements of the n = 2 {yields} 1 transitions in heliumlike xenon (Xe{sup 52+}) and hydrogenlike xenon (Xe{sup 53+}) were based on a new transmission-type crystal spectrometer of DuMond geometry. The resolving power of the developed spectrometer was sufficient for charge state specific observation allowing the determination of the electron-impact excitation cross section for the hydrogen- and heliumlike K{alpha} transitions. The disagreement with theoretically predicted values is a measure of the magnitude of the Breit interaction for the highly charged high-Z ions.

Widmann, K

1999-12-06T23:59:59.000Z

132

LCLS - The X-ray Laser Has Turned On  

SciTech Connect

On April 10, 2009 the Linac Coherent Light Source (LCLS), the world's first hard x-ray free electron laser, was brought to lasing. Producing an x-ray beam with over a billion times higher peak brightness that then most powerful existing syncrotron sources, it marked the beginning of a new era of science. The LCLS pulses arrive at a rate of 60 - 120 Hz in an energy range from 480 eV to 10 keV, with pulse lengths as short as a few fs to about 300 fs. Since October 2009, users have been performing experiments at the LCLS, and currently three of the six planned instruments are available. Although we stand only at the beginning of LCLS science, there is no doubt about the strong sense of early excitement.

Bergmann, Uwe [Linac Coherent Light Source

2010-11-03T23:59:59.000Z

133

X-ray irradiation in XTE J1817-330 and the inner radius of the truncated disc in the hard state  

E-Print Network (OSTI)

The key aspect of the very successful truncated disc model for the low/hard X-ray spectral state in black hole binaries is that the geometrically thin disc recedes back from the last stable orbit at the transition to this state. This has recently been challenged by direct observations of the low/hard state disc from CCD data. We reanalyze the Swift and RXTE campaign covering the 2006 outburst of XTE J1817-330 and show that these data actually strongly support the truncated disc model as the transition spectra unambiguously show that the disc begins to recede as the source leaves the disc dominated soft state. The disc radius inferred for the proper low/hard state is less clear-cut, but we show that the effect of irradiation from the energetically dominant hot plasma leads to an underestimate of the disc radius by a factor of 2-3 in this state. This may also produce the soft excess reported in some hard-state spectra. The inferred radius becomes still larger when the potential difference in stress at the inner boundary, increased colour temperature correction from incomplete thermalization of the irradiation, and loss of observable disc photons from Comptonization in the hot plasma are taken into account. We conclude that the inner disc radius in XTE J1817-330 in the low/hard spectral state is at least 6-8 times that seen in the disc dominated high/soft state, and that recession of the inner disc is the trigger for the soft--hard state transition, as predicted by the truncated disc models.

Marek Gierlinski; Chris Done; Kim Page

2008-03-04T23:59:59.000Z

134

Electronic structure of delta-doped La:SrTiO{sub 3} layers by hard x-ray photoelectron spectroscopy  

Science Conference Proceedings (OSTI)

We have employed hard x-ray photoemission (HAXPES) to study a delta-doped SrTiO{sub 3} layer that consisted of a 3-nm thickness of La-doped SrTiO{sub 3} with 6% La embedded in a SrTiO{sub 3} film. Results are compared to a thick, uniformily doped La:SrTiO{sub 3} layer. We find no indication of a band offset for the delta-doped layer, but evidence of the presence of Ti{sup 3+} in both the thick sample and the delta-layer, and indications of a density of states increase near the Fermi energy in the delta-doped layer. These results further demonstrate that HAXPES is a powerful tool for the non-destructive investigation of deeply buried doped layers.

Kaiser, A. M. [Department of Physics, University of California, Davis, California 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Peter-Gruenberg-Institut PGI-6, Forschungszentrum Juelich, 52425 Juelich (Germany); Gray, A. X. [Department of Physics, University of California, Davis, California 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Conti, G.; Fadley, C. S. [Department of Physics, University of California, Davis, California 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Jalan, B. [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States); Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minnesota 55455 (United States); Kajdos, A. P.; Stemmer, S. [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States); Gloskovskii, A. [Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Ueda, S.; Yamashita, Y.; Kobayashi, K. [NIMS Beamline Station at SPring-8, National Institute for Materials Science, Hyogo 679-5148 (Japan); Drube, W. [Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg (Germany)

2012-06-25T23:59:59.000Z

135

FREE-ELECTRON LASERS  

E-Print Network (OSTI)

1977. First Operation of a Free-Electron Laser. Phys . __Radiation from a High-Gain Free-Electeon Lasee Amplifier. ~1984. Variable-Wiggler Free-Electron-Laser Oscillat.ion.

Sessler, A.M.

2008-01-01T23:59:59.000Z

136

Low energy cut-offs and hard X-ray spectra in high-z radio-loud quasars: the Suzaku view of RBS315  

E-Print Network (OSTI)

We present the results from the Suzaku observation of the powerful radio-loud quasar RBS315 (z=2.69), for which a previous XMM-Newton observation showed an extremely flat X-ray continuum up to 10 keV (photon index Gamma=1.26) and indications of strong intrinsic absorption (N_H~10^22 cm^{-2} assuming neutral gas). The instrument for hard X-rays HXD/PIN allows us a detection of the source up to 50 keV. The broad-band continuum (0.5-50 keV) can be well modeled with a power-law with slope Gamma=1.5 (definitively softer than the continuum measured by XMM-Newton) above 1 keV with strong deficit of soft photons. The low-energy cut-off can be well fitted either with intrinsic absorption (with column density N_H~10^22 cm^{-2} in the quasar rest frame) or with a break in the continuum, with an extremely hard (Gamma =0.7) power-law below 1 keV. We construct the Spectral Energy Distribution of the source, using also optical-UV measurements obtained through a quasi-simultaneous UVOT/SWIFT observation. The shape of the SED is similar to that of other Flat Spectrum Radio Quasars (FSRQs) with similar power, making this source an excellent candidate for the detection in gamma-rays by GLAST. We model the SED with the synchrotron-Inverse Compton model usually applied to FSRQs, showing that the deficit of soft photons can be naturally interpreted as due to an intrinsic curvature of the spectrum near the low energy end of the IC component rather than to intrinsic absorption, although the latter possibility cannot be ruled out. We propose that in at least a fraction of the radio-loud QSOs at high redshift the cut-off in the soft X-ray band can be explained in a similar way. Further studies are required to distinguish between the two alternatives.

F. Tavecchio; L. Maraschi; G. Ghisellini; J. Kataoka; L. Foschini; R. M. Sambruna; G. Tagliaferri

2007-05-02T23:59:59.000Z

137

Multilayers for next generation x-ray sources  

Science Conference Proceedings (OSTI)

Multilayers are artificially layered structures that can be used to create optics and optical elements for a broad range of x-ray wavelengths, or can be optimized for other applications. The development of next generation x-ray sources (synchrotrons and x-ray free electron lasers) requires advances in x-ray optics. Newly developed multilayer-based mirrors and optical elements enabled efficient band-pass filtering, focusing and time resolved measurements in recent FLASH (Free Electron LASer in Hamburg) experiments. These experiments are providing invaluable feedback on the response of the multilayer structures to high intensity, short pulsed x-ray sources. This information is crucial to design optics for future x-ray free electron lasers and to benchmark computer codes that simulate damage processes.

Bajt, S; Chapman, H N; Spiller, E; Hau-Riege, S; Alameda, J; Nelson, A J; Walton, C C; Kjornrattanawanich, B; Aquila, A; Dollar, F; Gullikson, E; Tarrio, C

2007-05-04T23:59:59.000Z

138

THE EFFECT OF CORONAL RADIATION ON A RESIDUAL INNER DISK IN THE LOW/HARD SPECTRAL STATE OF BLACK HOLE X-RAY BINARY SYSTEMS  

Science Conference Proceedings (OSTI)

Thermal conduction between a cool accretion disk and a hot inner corona can result in either evaporation of the disk or condensation of the hot corona. At low mass accretion rates, evaporation dominates and can completely remove the inner disk. At higher mass accretion rates, condensation becomes more efficient in the very inner regions, so that part of the mass accretes via a weak (initially formed) inner disk which is separated from the outer disk by a fully evaporated region at mid radii. At still higher mass accretion rates, condensation dominates everywhere, so there is a continuous cool disk extending to the innermost stable circular orbit. We extend these calculations by including the effect of irradiation by the hot corona on the disk structure. The flux which is not reflected is reprocessed in the disk, adding to the intrinsic thermal emission from gravitational energy release. This increases the seed photons for Compton cooling of the hot corona, enhancing condensation of the hot flow, and reinforcing the residual inner disk rather than evaporating it. Our calculations confirm that a residual inner disk can coexist with a hard, coronally dominated spectrum over the range of 0.006< m-dot <0.016 (for {alpha} = 0.2). This provides an explanation for the weak thermal component seen recently in the low/hard state of black hole X-ray binary systems.

Liu, B. F. [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China); Done, C. [Department of Physics, University of Durham, South Road, Durham, DH1 3LE (United Kingdom); Taam, Ronald E., E-mail: bfliu@ynao.ac.cn, E-mail: r-taam@northwestern.edu, E-mail: bfliu@nao.cas.cn [Department of Physics and Astronomy, Northwestern University, 2131 Tech Drive, Evanston, IL 60208 (United States)

2011-01-01T23:59:59.000Z

139

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

NLE Websites -- All DOE Office Websites (Extended Search)

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...

140

Reliable before-fabrication forecasting of expected surface slope distributions for x-ray optics  

E-Print Network (OSTI)

of x-ray optics for the LCLS free-electron laser, Proc.beamlines and diagnostics at LCLS, Nucl. Instrum. Methods A

Yashchuk, Yekaterina V.

2013-01-01T23:59:59.000Z

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.


141

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

NLE Websites -- All DOE Office Websites (Extended Search)

10:00am SLAC, Bldg. 137, Room 226 Keoki Seu Seminar: With the advent of free electron lasers there has been interest in using coherent x-rays to probe condensed matter systems....

142

Lensless Imaging of Magnetic Nanostructures by X-ray Spectro...  

NLE Websites -- All DOE Office Websites (Extended Search)

F. Schlotter and J. Sthr (SSRL) The unprecedented properties of X-ray free electron lasers (X-FELs) under development world wide will open the door for entirely new classes of...

143

SLAC National Accelerator Laboratory - X-ray Laser Brings Cellular...  

NLE Websites -- All DOE Office Websites (Extended Search)

a March experiment indicates it has, for the first time, used an X-ray free-electron laser - SLAC's Linac Coherent Light Source - to reconstitute the structure of a G...

144

Science Challenges & Opportunities for an Advanced X-ray Free...  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Challenges & Opportunities for an Advanced X-ray Free-electron Laser Wednesday, October 2, 2013 - 3:00pm SLAC, Kavli 3rd Floor Conference Room Robert Schoenlein, Lawrence...

145

A Large-Area Cross-Correlation Study of High Galactic Latutude Soft and Hard X-ray Skies  

E-Print Network (OSTI)

We have made cross-correlation analyses of (2 -- 15 keV) HEAO A2 and 1 keV ROSAT PSPC All-Sky Survey maps over a selected area ($\\sim$ 4000 deg$^2$) with high galactic latitude (b>40 deg). We have calculated the correlations for the bright ROSAT sources and residual background separately with the \\HEAO A2 TOT (2 -- 10 keV) and HRD (5 -- 15 keV) maps. The amplitude of the bright \\ROSAT source -- A2 CCFs are consistent with expectations from model populations of AGNs and clusters of galaxies, which emit in both bands. However, the residual ROSAT background -- A2 CCFs amplitude at zero degree are about a factor of three larger than that expected from the model populations. Our soft-hard zero-lag and angular CCF results have been compared with the 1 keV auto-correlation function (ACF) found by Soltan et al. (1995) for the same ROSAT data. Their significant angular CCF at a scale of ACF has a hot plasma spectrum with kT\\sim 2 keV, contribution of this component is consistent with both our zero-lag CCF in excess of the population synthesis model prediction and the upper-limit to the angular CCF at \\theta \\sim 2.5 deg. On the other hand, if this component has a lower temperature or a steeper spectrum, a major modification to the population synthesis model and/or an introduction of new classes would be needed.

Takamitsu Miyaji; Guenther Hasinger; Roland Egger; Joachim Truemper; Michael J. Freyberg

1996-01-30T23:59:59.000Z

146

Free electron lasers  

SciTech Connect

A review of experimental and theoretical concepts of a free electron laser is given. The possibilities of scaling these lasers to high powers are discussed. (MOW)

Brau, C.A.

1980-01-01T23:59:59.000Z

147

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

148

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

149

A recirculating linac-based facility for ultrafast X-ray science  

SciTech Connect

We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac, in particular the incorporation of EUV and soft x-ray production. The project has been named LUX - Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10 s fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short-pulse photon production in the 1-10 keV range. High-brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free-electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by four passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility.

Corlett, J.N; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wolski, A.; Zholents, A.; Placidi, M.; Pirkl, W.; Parmigiani, F.

2003-05-06T23:59:59.000Z

150

Catalac free electron laser  

DOE Patents (OSTI)

A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac is described. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator, or as an amplifier in conjunction with a master oscillator laser.

Brau, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

1979-12-12T23:59:59.000Z

151

Catalac free electron laser  

DOE Patents (OSTI)

A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator or as an amplifier in conjunction with a master oscillator laser.

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

1982-01-01T23:59:59.000Z

152

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (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.

153

2011 X-Ray Science Gordon Research Conference (August 7-12, 2011, Colby, College. Waterville, ME)  

SciTech Connect

The 2011 Gordon Research Conference on X-ray Science will feature forefront x-ray-based science enabled by the rapid improvements in synchrotron and x-ray laser sources. Across the world, x-ray sources are playing an increasingly important role in physics, materials, chemistry, and biology, expanding into ever broadening areas of science and engineering. With the first hard x-ray free electron laser source beginning operation and with other advanced x-ray sources operational and planned, it is a very exciting and pivotal time for exchange ideas about the future of x-ray science and applications. The Conference will provide the forum for this interaction. An international cast of speakers will illuminate sessions on ultrafast science, coherence, imaging, in situ studies, extreme conditions, new developments in optics, sources, and detectors, inelastic scattering, nanoscience, life science, and energy sciences. The Conference will bring together investigators at the forefront of these areas, and will provide a venue for young scientists entering a career in x-ray research to present their research in poster format, hold discussions in a friendly setting, and exchange ideas with leaders in the field. Some poster presenters will be selected for short talks. The collegial atmosphere of this Conference, with ample time for discussion as well as opportunities for informal gatherings in the afternoons and evenings, will provide an avenue for scientists from different disciplines to exchange ideas about forefront x-ray techniques and will promote cross-fertilization between the various research areas represented.

Gregory Stephenson

2011-08-12T23:59:59.000Z

154

Progress Toward the Wisconsin Free Electron Laser  

SciTech Connect

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, J; 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

155

Progress toward the Wisconsin Free Electron Laser  

SciTech Connect

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

156

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

157

Optimization for Single-Spike X-Ray FELs at LCLS with a Low Charge Beam  

Science Conference Proceedings (OSTI)

The Linac Coherent Light Source is an x-ray free-electron laser at the SLAC National Accelerator Laboratory, which is operating at x-ray wavelengths of 20-1.2 Angstrom with peak brightness nearly ten orders of magnitude beyond conventional synchrotron radiation sources. At the low charge operation mode (20 pC), the x-ray pulse length can be LCLS), the world's first hard x-ray Free electron laser (FEL), has started operation since 2009. With nominal operation charge of 250 pC, the generated x-ray pulse length is from 70 fs to a few hundred fs. This marks the beginning of a new era of ultrashort x-ray sciences. In addition, a low charge (20pC) operation mode has also been established. Since the collective effects are reduced at the low charge mode, we can increase the compression factor and still achieve a few kA peak current. The expected electron beam and x-ray pulses are less than 10 fs. There are growing interests in even shorter x-ray pulses, such as fs to sub-fs regime. One of the simple solutions is going to even lower charge. As discussed, single-spike x-ray pulses can be generated using 1 pC charge. However, this charge level is out of the present LCLS diagnostic range. 20 pC is a reasonable operation charge at LCLS, based on the present diagnostic system. At 20 pC in the soft x-ray wavelength regime, we have experimentally demonstrated that FEL can work at undercompression or over-compression mode, such as 1 degree off the full-compression; at full-compression, however, there is almost no lasing. In hard x-ray wavelength regime, we observed that there are reasonable photons generated even at full-compression mode, although the photon number is less than that from under-compression or over-compression mode. Since we cannot measure the x-ray pulse length at this time scale, the machine is typically optimized for generating maximum photons, not minimum pulse length. In this paper, we study the methods of producing femtosecond (or single-spike) x-ray pulses at LCLS with 20 pC charge, based on start-to-end simulations. Figure 1 shows a layout of LCLS. The compression in the second bunch compressor (BC2) determines the final e-beam bunch length. However, the laser heater, dog-leg after the main linac (DL2) and collective effects also affect the final bunch length. To adjust BC2 compression, we can either change the L2 phase or BC2 R{sub 56}. In this paper we only tune L2 phase while keep BC2 R{sub 56} fixed. For the start-to-end simulations, we used IMPACT-T and ELEGANT tracking from the photocathode to the entrance of the undulator, after that the FEL radiation was simulated with GENESIS. IMPACT-T tracks about 10{sup 6} particles in the injector part until 135 MeV, including 3D space charge force. The output particles from IMPACT-T are smoothed and increased to 12 x 10{sup 6} to reduce high-frequency numerical noise for subsequent ELEGANT simulations, which include linear and nonlinear transport effects, a 1D transient model of CSR, and longitudinal space charge effects, as well as geometric and resistive wake fields in the accelerator. In GENESIS part, the longitudinal wake field from undulator chamber and longitudinal space field are also included.

Wang, L.; Ding, Y.; Huang, Z.; /SLAC

2011-12-14T23:59:59.000Z

158

Neutron and X-ray Scattering Investigations of Microscopic Energy ...  

Science Conference Proceedings (OSTI)

A Case Study in Future Energy Challenges: Towards In Situ Hard X-ray Microscopy of ... of Crystal Structure and Domain Character in Lead Free Piezoceramics.

159

Particle Accelerator & X-Ray Optics | Argonne National Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

Hard X-Ray Quad Collimator Facilitates Microcrystallography Experiments Isotopic Abundance in Atom Trap Trace Analysis Nanomaterials Analysis using a Scanning Electron Microscope...

160

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (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.

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  

NLE Websites -- All DOE Office Websites (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.

162

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (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.

163

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (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.

164

X-Ray Topography  

Science Conference Proceedings (OSTI)

Sep 17, 2009 ... Stress Mapping Analysis by Ray Tracing (SMART): A New Technique ... technique of synchrotron X-ray topography, where a grid made out of...

165

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

166

X-ray generator  

DOE Patents (OSTI)

Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

Dawson, John M. (Los Angeles, CA)

1976-01-01T23:59:59.000Z

167

Resonant Auger Effect at High X-Ray Intensity  

SciTech Connect

The resonant Auger effect of atomic neon exposed to high-intensity x-ray radiation in resonance with the 1s {yields} 3p transition is discussed. High intensity here means that the x-ray peak intensity is sufficient ({approx} 10{sup 18} W/cm{sup 2}) to induce Rabi oscillations between the neon ground state and the 1s{sup -1}3p ({sup 1}P) state within the relaxation lifetime of the inner-shell vacancy. For the numerical analysis presented, an effective two-level model, including a description of the resonant Auger decay process, is employed. Both coherent and chaotic x-ray pulses are treated. The latter are used to simulate radiation from x-ray free-electron lasers based on the principle of self-amplified spontaneous emission. Observing x-ray-driven atomic population dynamics in the time domain is challenging for chaotic pulse ensembles. A more practical option for experiments using x-ray free-electron lasers is to measure the line profiles in the kinetic energy distribution of the resonant Auger electron. This provides information on both atomic population dynamics and x-ray pulse properties.

Rohringer, N; Santra, R

2008-03-27T23:59:59.000Z

168

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

169

Gamma Radiation & X-Rays  

NLE Websites -- All DOE Office Websites (Extended Search)

Gamma Radiation and X-Rays 1. Gamma radiation and X-rays are electromagnetic radiation like visible light, radio waves, and ultraviolet light. These electromagnetic radiations...

170

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

Science Conference Proceedings (OSTI)

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

Boutet, Sebastien

2011-08-16T23:59:59.000Z

171

Argonne CNM: X-Ray Microscopy Capabilities  

NLE Websites -- All DOE Office Websites (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.

172

X-ray microtomography  

SciTech Connect

In this tutorial, we describe X-ray microtomography as a technique to nondestructively characterize material microstructure in three dimensions at a micron level spatial resolution. While commercially available laboratory scale instrumentation is available, we focus our attention on synchrotron-based systems, where we can exploit a high flux, monochromatic X-ray beam to produce high fidelity three-dimensional images. A brief description of the physics and the mathematical analysis behind the technique is followed by example applications to specific materials characterization problems, with a particular focus on the utilization of three-dimensional image processing that can be used to extract a wide range of useful information.

Landis, Eric N., E-mail: landis@maine.edu [Department of Civil and Environmental Engineering, University of Maine, 5711 Boardman Hall, Orono, Maine 04469 (United States); Keane, Denis T., E-mail: dtkeane@northwestern.edu [Department of Materials Science and Engineering, Northwestern University (United States); DND-CAT, Advanced Photon Source, Argonne National Laboratory, Bldg. 432/A002, 9700 S. Cass Ave, Argonne, Illinois 60439 (United States)

2010-12-15T23:59:59.000Z

173

Circular free-electron laser  

DOE Patents (OSTI)

A high efficiency, free electron laser is described 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, C.A.; Kurnit, N.A.; Cooper, R.K.

1982-01-26T23:59:59.000Z

174

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

175

Refractive optical elements and optical system for high energy x-ray microscopy  

Science Conference Proceedings (OSTI)

In material science, X-ray radiation with photon energies above 25 keV is used because of its penetration into high density materials. Research of the inner structure of novel materials, such as electrodes in high power batteries for engines, require X-ray microscopes operating in the hard X-ray energy range. A flexible X-ray microscope for hard X-rays with photon energies higher than 25 keV will be realized at the synchrotron source ANKA in Karlsruhe, Germany. The device will use refractive X-ray lenses as condenser as well as objective lenses.

Simon, M.; Altapova, V.; Baumbach, T.; Kluge, M.; Last, A.; Marschall, F.; Mohr, J.; Nazmov, V.; Vogt, H. [Karlsruhe Institute of Technology, Institute of Microstructure Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Karlsruhe Institute of Technology, Laboratory for Applications of Synchrotron Radiation, Engesser Strasse 15, 76131 Karlsruhe (Germany); Karlsruhe Institute of Technology, Institute of Microstructure Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

2012-05-17T23:59:59.000Z

176

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

177

Rf feedback free electron laser  

DOE Patents (OSTI)

A free electron laser system and electron beam system for a free electron laser are provided 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, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

1979-11-02T23:59:59.000Z

178

X-ray chemistry in envelopes around young stellar objects  

E-Print Network (OSTI)

We present chemical models of the envelope of a young stellar object (YSO) exposed to a central X-ray source. The models are applied to the massive star-forming region AFGL 2591 for different X-ray fluxes. The total X-ray ionization rate is dominated by the `secondary' ionization rate of H2 resulting from fast electrons. The carbon, sulphur and nitrogen chemistries are discussed. It is found that He+ and H3+ are enhanced and trigger a peculiar chemistry. Several molecular X-ray tracers are found and compared to tracers of the far ultraviolet (FUV) field. Like ultraviolet radiation fields, X-rays enhance simple hydrides, ions and radicals. In contrast to ultraviolet photons, X-rays can penetrate deep into the envelope and affect the chemistry even at large distances from the source. Whereas the FUV enhanced species cover a region of 200-300 AU, the region enhanced by X-rays is >1000 AU. Best-fit models for AFGL 2591 predict an X-ray luminosity LX > 1e+31 ergs/s with a hard X-ray spectrum TX > 3e+07 K. Furthermore, we find LX/Lbol ~ 1e-6. The chemistry of the bulk of the envelope mass is dominated by cosmic-ray induced reactions rather than by X-ray induced ionization for X-ray luminosities LX < 1e+33 ergs/s. The calculated line intensities of HCO+ and HCS+ show that high-J lines are more affected than lower J lines by the presence of X-rays due to their higher critical densities, and that such differences are detectable even with large aperture single-dish telescopes. Future instruments such as Herschel-HIFI or SOFIA will be able to observe X-ray enhanced hydrides whereas the sensitivity and spatial resolution of ALMA is well-suited to measure the size and geometry of the region affected by X-rays.

P. Staeuber; S. D. Doty; E. F. van Dishoeck; A. O. Benz

2005-06-14T23:59:59.000Z

179

Linda Young Named to Head X-ray Science Division  

NLE Websites -- All DOE Office Websites (Extended Search)

to the APS Hard X-ray Nanoprobe Earns an R&D 100 Award Winans of XSD Elected to ACS Fellowship Gluskin of Photon Sciences named Argonne Distinguished Fellow UChicago...

180

Bendable Focusing X-Ray Optics for the ALS and the LCLS/FEL: Design, Metrology, and Performance  

E-Print Network (OSTI)

Optics for the ALS and the LCLS/FEL: Design, Metrology, andwas performed in support of the AMO/LCLS project at SLAC. *Coherent Light Source (LCLS) x-ray free electron laser (FEL)

Yashchuk, V. V.

2010-01-01T23:59:59.000Z

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

Femtosecond Time-Delay X-ray Holography  

NLE Websites -- All DOE Office Websites (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.

182

X-ray Security Screening  

Science Conference Proceedings (OSTI)

National and International Standards for X-ray Security Screening Applications. Summary: The primary objective of this ...

2013-03-13T23:59:59.000Z

183

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

184

Scanning x-ray microscope  

Science Conference Proceedings (OSTI)

A scanning x-ray microscope is described including: an x-ray source capable of emitting a beam of x-rays; a collimator positioned to receive the beam of x-rays and to collimate this beam, a focusing cone means to focus the beam of x-rays, directed by the collimator, onto a focal plane, a specimen mount for supporting a specimen in the focal plane to receive the focused beam of x-rays, and x-ray beam scanning means to relatively move the specimen and the focusing cone means and collimator to scan the focused x-ray beam across the specimen. A detector is disposed adjacent the specimen to detect flourescent photons emitted by the specimen upon exposure to the focused beam of x-rays to provide an electrical output representative of this detection. Means are included for displaying and/or recording the information provided by the output from the detector, as are means for providing information to the recording and/or display means representative of the scan rate and position of the focused x-ray beam relative to the specimen whereby the recording and/or display means can correlate the information received to record and/or display quantitive and distributive information as to the quantity and distribution of elements detected in the specimen. Preferably there is provided an x-ray beam modulation means upstream, relative to the direction of emission of the xray beam, of the focusing cone means.

Wang, C.

1982-02-23T23:59:59.000Z

185

X-ray lithography source  

SciTech Connect

A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

Piestrup, Melvin A. (Woodside, CA); Boyers, David G. (Mountain View, CA); Pincus, Cary (Sunnyvale, CA)

1991-01-01T23:59:59.000Z

186

X-ray lithography source  

DOE Patents (OSTI)

A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits is disclosed. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and eliminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an excellent moderate-priced X-ray source for lithography. 26 figures.

Piestrup, M.A.; Boyers, D.G.; Pincus, C.

1991-12-31T23:59:59.000Z

187

Hybrid free electron laser devices  

Science Conference Proceedings (OSTI)

We consider hybrid free electron laser devices consisting of Cerenkov and undulator sections. We will show that they can in principle be used as segmented devices and also show the possibility of exploiting Cerenkov devices for the generation of nonlinear harmonic coherent power. We discuss both oscillator and amplifier schemes.

Asgekar, Vivek; Dattoli, G. [Department of Physics, University of Pune, Pune 411007 (India); ENEA, Unita Tecnico Scientifica Technologie Fisiche, Avanzate, Centro Ricerche Frascati, C.P. 65-00044 Frascati, Rome (Italy)

2007-03-15T23:59:59.000Z

188

Laser Phase Errors in Seeded Free Electron Lasers  

SciTech Connect

Harmonic seeding of free electron lasers has attracted significant attention as a method for producing transform-limited pulses in the soft x-ray region. Harmonic multiplication schemes extend seeding to shorter wavelengths, but also amplify the spectral phase errors of the initial seed laser, and may degrade the pulse quality and impede production of transform-limited pulses. In this paper we consider the effect of seed laser phase errors in high gain harmonic generation and echo-enabled harmonic generation. We use simulations to confirm analytical results for the case of linearly chirped seed lasers, and extend the results for arbitrary seed laser envelope and phase.

Ratner, D.; Fry, A.; Stupakov, G.; White, W.; /SLAC

2012-04-17T23:59:59.000Z

189

Design Alternatives for a Free Electron Laser Facility  

Science Conference Proceedings (OSTI)

The University of Wisconsin-Madison is continuing design efforts for a vacuum ultraviolet/X-ray Free Electron Laser facility. The design incorporates seeding the FEL to provide fully coherent photon output at energies up to {approx}1 keV. The focus of the present work is to minimize the cost of the facility while preserving its performance. To achieve this we are exploring variations in the electron beam driver for the FEL, in undulator design, and in the seeding mechanism. Design optimizations and trade-offs between the various technologies and how they affect the FEL scientific program will be presented.

Jacobs, K; Bosch, R A; Eisert, D; Fisher, M V; Green, M A; Keil, R G; Kleman, K J; Kulpin, J G; Rogers, G C; Wehlitz, R; Chiang, T; Miller, T J; Lawler, J E; Yavuz, D; Legg, R A

2012-07-01T23:59:59.000Z

190

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

NLE Websites -- All DOE Office Websites (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

191

Miniature x-ray source  

DOE Patents (OSTI)

A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an 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 highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

Trebes, James E. (Livermore, CA); Stone, Gary F. (Livermore, CA); Bell, Perry M. (Tracy, CA); Robinson, Ronald B. (Modesto, CA); Chornenky, Victor I. (Minnetonka, MN)

2002-01-01T23:59:59.000Z

192

Synchrotron X-ray Measurements  

Science Conference Proceedings (OSTI)

... fine structure (EXAFS) spectroscopy; (3) variable kinetic energy X-ray ... advanced materials is critical to the development and optimization of products ...

2012-10-04T23:59:59.000Z

193

X-ray Absorption Spectroscopy  

SciTech Connect

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

Yano, Junko; Yachandra, Vittal K.

2009-07-09T23:59:59.000Z

194

Computational Simulations of High Intensity X-Ray Matter Interaction  

SciTech Connect

Free electron lasers have the promise of producing extremely high-intensity short pulses of coherent, monochromatic radiation in the 1-10 keV energy range. For example, the Linac Coherent Light Source at Stanford is being designed to produce an output intensity of 2 x 10{sup 14} W/cm{sup 2} in a 230 fs pulse. These sources will open the door to many novel research studies. However, the intense x-ray pulses may damage the optical components necessary for studying and controlling the output. At the full output intensity, the dose to optical components at normal incidence ranges from 1-10 eV/atom for low-Z materials (Z < 14) at photon energies of 1 keV. It is important to have an understanding of the effects of such high doses in order to specify the composition, placement, and orientation of optical components, such as mirrors and monochromators. Doses of 10 eV/atom are certainly unacceptable since they will lead to ablation of the surface of the optical components. However, it is not precisely known what the damage thresholds are for the materials being considered for optical components for x-ray free electron lasers. In this paper, we present analytic estimates and computational simulations of the effects of high-intensity x-ray pulses on materials. We outline guidelines for the maximum dose to various materials and discuss implications for the design of optical components.

London, R A; Rionta, R; Tatchyn, R; Roessler, S

2001-08-02T23:59:59.000Z

195

Femtosecond dark-field imaging with an X-ray free electron laser  

DOE Data Explorer (OSTI)

This data was collected as part of the same experiment as the data deposited in [ID16](id-16.html). Experiment details are given in [Loh, N.D. et al.](http://dx.doi.org/10.1038/nature11222)

Martin, A. V.

196

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

E-Print Network (OSTI)

Radiation from the Brookhaven Vacuum-Ultraviolet ElectronArgonne National Laboratory, Brookhaven National Laboratory,Physicist Physics Department Brookhaven National Laboratory

Staples, John

2009-01-01T23:59:59.000Z

197

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

E-Print Network (OSTI)

Physical Society, 1996 R&D 100 Award for global feedbackLaboratory, Berkeley, CA R&D Engineer, Lawrence LivermoreLaboratory, Livermore, CA R&D Engineer, Weyerhaeuser

Staples, John

2009-01-01T23:59:59.000Z

198

Obtaining attosecond X-ray pulses using a self-amplified spontaneous emission free electron laser  

E-Print Network (OSTI)

1369 (2004). [10] W. B. Colson, in Laser Handbook, Volume 6:Free Elec- tron Lasers (North-Holland, Amsterdam, 1990),B. Murphy and C. Pellegrini, in Laser Handbook, Vol- ume 6:

Zholents, A.A.; Penn, G.

2005-01-01T23:59:59.000Z

199

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

E-Print Network (OSTI)

S.H. Kim, D. Mangra, ORNL-SNS; D. Barni, C. Pagani, P.for the Spallation Neutron Source (SNS) project, 50. StuartSpallation Neutron Source (SNS) cavities operate. This may

Staples, John

2009-01-01T23:59:59.000Z

200

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

E-Print Network (OSTI)

Radiation Lightsource (SSRL), Photon Science (PS), andRadiation Laboratory (SSRL) Member of the editorial board ofradiation user facilities SSRL (based on SPEAR3, a third-

Staples, John

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.


201

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

E-Print Network (OSTI)

P. Innocenzi, IKNO, a user facility for coherent terahertzAn ultimate experimental user facility will bring additionalgun has to operate in a user facility . Table 2.1 summarizes

Staples, John

2009-01-01T23:59:59.000Z

202

Obtaining attosecond X-ray pulses using a self-amplified spontaneous emission free electron laser  

E-Print Network (OSTI)

A 429, 243 (1999). [18] LCLS Design Study Group, ReportLinac Coherent Light Source (LCLS) [18], except the electron

Zholents, A.A.; Penn, G.

2005-01-01T23:59:59.000Z

203

Design Studies for a VUV--Soft X-ray Free-Electron Laser Array  

E-Print Network (OSTI)

bunch arrival time in the LCLS, and another system that willFERMI@Elettra and 100 fs for LCLS, both requiring about 200-

Corlett, J.

2010-01-01T23:59:59.000Z

204

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

E-Print Network (OSTI)

2007). 41. P. Emma for the LCLS commissioning team, PAC2009Test Facility for the LCLS, SLAC-TN-07-005, (2007). John N.Professional/Academic Director, LCLS Strategic Projects

Staples, John

2009-01-01T23:59:59.000Z

205

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

DOE Data Explorer (OSTI)

The diffraction pattern of this entry corresponds to the one shown in **figure 2a** of the corresponding citation.

Chapman, H. N.

206

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

E-Print Network (OSTI)

elements, Jan 2000 Invention Disclosure Compact, tunable,field multipole, May 1997 Invention Disclosure Tunable pure

Staples, John

2009-01-01T23:59:59.000Z

207

X-ray Imaging Workshop  

NLE Websites -- All DOE Office Websites (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.

208

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

209

Tokamak x ray diagnostic instrumentation  

SciTech Connect

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

210

RECENT X-RAY VARIABILITY OF {eta} CARINAE: THE QUICK ROAD TO RECOVERY  

Science Conference Proceedings (OSTI)

We report continued monitoring of the superluminous binary system {eta} Car by the Proportional Counter Array on the Rossi X-ray Timing Observatory (RXTE) through the 2009 X-ray minimum. The RXTE campaign shows that the minimum began on 2009 January 16, consistent with the phasings of the two previous minima, and overall, the temporal behavior of the X-ray emission was similar to that observed by RXTE in the previous two cycles. However, important differences did occur. The 2-10 keV X-ray flux and X-ray hardness decreased in the 2.5 year interval leading up to the 2009 minimum compared to the previous cycle. Most intriguingly, the 2009 X-ray minimum was about 1 month shorter than either of the previous two minima. During the egress from the 2009 minimum the X-ray hardness increased markedly as it had during egress from the previous two minima, although the maximum X-ray hardness achieved was less than the maximum observed after the two previous recoveries. We suggest that the cycle-to-cycle variations, especially the unexpectedly early recovery from the 2009 X-ray minimum, might have been the result of a decline in {eta} Car's wind momentum flux produced by a drop in {eta} Car's mass loss rate or wind terminal velocity (or some combination), though if so the change in wind momentum flux required to match the X-ray variation is surprisingly large.

Corcoran, M. F.; Hamaguchi, K. [CRESST and X-ray Astrophysics Laboratory, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Pittard, J. M. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Russell, C. M. P.; Owocki, S. P. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Parkin, E. R. [Institut d'Astrophysique et de Geophysique, Universite de Liege, 17, Allee du 6 Aout, B5c, B-4000 Sart Tilman (Belgium); Okazaki, A. [Faculty of Engineering, Hokkai-Gakuen University, Toyohira-ku, Sapporo 062-8605 (Japan)

2010-12-20T23:59:59.000Z

211

Sub-Picosecond X-Ray Pulses Workshop  

NLE Websites -- All DOE Office Websites (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

212

X-ray Transition Energies Search Form  

Science Conference Proceedings (OSTI)

[skip navigation] X-ray Transition Energies Database Main Page Search for X-ray transition energies by element(s), transition ...

213

Beam Conditioning for Free Electron Lasers:Consequences and Methods  

Science Conference Proceedings (OSTI)

The consequences of beam conditioning in four example cases [VISA, a soft x-ray free-electron laser (FEL), LCLS, and a 'Greenfield' FEL] are examined. It is shown that in emittance limited cases, proper conditioning reduces sensitivity to the transverse emittance and, furthermore, allows for stronger focusing in the undulator. Simulations show higher saturation power, with gain lengths reduced by a factor of 2 or more. The beam dynamics in a general conditioning system are studied, with 'matching conditions' derived for achieving conditioning without growth in the effective emittance. Various conditioning lattices are considered, and expressions derived for the amount of conditioning provided in each case when the matching conditions are satisfied. These results show that there is no fundamental obstacle to producing beam conditioning, and that the problem can be reduced to one of proper lattice design. Nevertheless, beam conditioning will not be easy to implement in practice.

Wolski, A.; Penn, G.; Sessler, A.; Wurtele, J.; /LBL, Berkeley /UC, Berkeley, Astron. Dept.

2010-12-14T23:59:59.000Z

214

Soft x-ray scattering using FEL radiation for probing near-solid density plasmas at few electronvolt temperatures  

DOE Green Energy (OSTI)

We report on soft x-ray scattering experiments on cryogenic hydrogen and simple metal targets. As a source of intense and ultrashort soft x-ray pulses we have used free-electron laser radiation at 92 eV photon energy from FLASH at DESY, Hamburg. X-ray pulses with energies up to 100 {micro}J and durations below 50 fs provide interaction with the target leading simultaneously to plasma formation and scattering. Experiments exploiting both of these interactions have been carried out, using the same experimental setup. Firstly, recording of soft x-ray inelastic scattering from near-solid density hydrogen plasmas at few electronvolt temperatures confirms the feasibility of this diagnostics technique. Secondly, the soft x-ray excitation of few electronvolt solid-density plasmas in simple metals could be studied by recording soft x-ray line and continuum emission integrated over emission times from fs to ns.

Toleikis, S; Faustlin, R R; Cao, L; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gode, S; Gregori, G; Irsig, R; Laarmann, T; Lee, H J; Li, B; Meiwes-Broer, K; Przystawik, A; Radcliffe, P; Redmer, R; Tavella, F; Thiele, R; Tiggesbaumker, J; Truong, N X; Uschmann, I; Zastrau, U; Tschentscher, T

2009-03-03T23:59:59.000Z

215

Beam Dynamics Study of X-Band Linac Driven X-Ray FELS  

Science Conference Proceedings (OSTI)

Several linac driven X-ray Free Electron Lasers (XFELs) are being developed to provide high brightness photon beams with very short, tunable wavelengths. In this paper, three XFEL configurations are proposed that achieve LCLS-like performance using X-band linac drivers. These linacs are more versatile, efficient and compact than ones using S-band or C-band rf technology. For each of the designs, the overall accelerator layout and the shaping of the bunch longitudinal phase space are described briefly. During the last 40 years, the photon wavelengths from linac driven FELs have been pushed shorter by increasing the electron beam energy and adopting shorter period undulators. Recently, the wavelengths have reached the X-ray range, with FLASH (Free-Electron Laser in Hamburg) and LCLS (Linac Coherent Light Source) successfully providing users with soft and hard X-rays, respectively. FLASH uses a 1.2 GeV L-band (1.3 GHz) superconducting linac driver and can deliver 10-70 fs FWHM long photon pulses in a wavelength range of 44 nm to 4.1 nm. LCLS uses the last third of the SLAC 3 km S-band (2.856 GHz) normal-conducting linac to produce 3.5 GeV to 15 GeV bunches to generate soft and hard X-rays with good spatial coherence at wavelengths from 2.2 nm to 0.12 nm. Newer XFELs (at Spring8 and PSI) use C-band (5.7 GHz) normal-conducting linac drivers, which can sustain higher acceleration gradients, and hence shorten the linac length, and are more efficient at converting rf energy to bunch energy. The X-band (11.4 GHz) rf technology developed for NLC/GLC offers even higher gradients and efficiencies, and the shorter rf wavelength allows more versatility in longitudinal bunch phase space compression and manipulation. In the following sections, three different configurations of X-band linac driven XFELs are described that operate from 6 to 14 GeV. The first (LOW CHARGE DESIGN) has an electron bunch charge of only 10 pC; the second (OPTICS LINEARIZATION DESIGN) is based on optics linearization of the longitudinal phase space in the first stage bunch compressor and can operate with either a high (250 pC) or low (20 pC) bunch charge; and the third (LCLS INJECTOR DESIGN) is similar to LCLS but uses an X-band linac after the first stage bunch compressor at 250 MeV to achieve a final beam energy up to 14 GeV. Compared with LCLS, these X-band linacs are at least a factor of three shorter.

Adolphsen, C.; Limborg-Deprey, C.; Raubenheimer, T.O.; Wu, J.; /SLAC; Sun, Y.; /SLAC

2011-12-13T23:59:59.000Z

216

Quiet Sun X-rays as Signature for New Particles  

E-Print Network (OSTI)

We have studied published data from the Yohkoh solar X-ray mission, with the purpose of searching for signals from radiative decays of new, as yet undiscovered massive neutral particles. This search is based on the prediction that solar axions of the Kaluza-Klein type should result in the emission of X-rays from the Sun direction beyond the limb with a characteristic radial distribution. These X-rays should be observed more easily during periods of quiet Sun. An additional signature is the observed emission of hard X-rays by SMM, NEAR and RHESSI. The recent observation made by RHESSI of a continuous emission from the non-flaring Sun of X-rays in the 3 to ~15 keV range fits the generic axion scenario. This work also suggests new analyses of existing data, in order to exclude instrumental effects; it provides the rationale for targeted observations with present and upcoming (solar) X-ray telescopes, which can provide the final answer on the nature of the signals considered here. Such measurements become more promising during the forthcoming solar cycle minimum with an increased number of quiet Sun periods.

K. Zioutas; K. Dennerl; L. DiLella; D. H. H. Hoffmann; J. Jacoby; Th. Papaevangelou

2004-03-08T23:59:59.000Z

217

Formation and destruction of jets in X-ray binaries  

E-Print Network (OSTI)

Neutron-star and black-hole X-ray binaries (XRBs) exhibit radio jets, whose properties depend on the X-ray spectral state and history of the source. In particular, black-hole XRBs emit compact, steady radio jets when they are in the so-called hard state, the jets become eruptive as the sources move toward the soft state, disappear in the soft state, and re-appear when the sources return to the hard state. On the other hand, jets from neutron-star X-ray binaries are typically weaker radio emitters than the black-hole ones at the same X-ray luminosity and in some cases radio emission is detected in the soft state. Significant phenomenology has been accumulated so far regarding the spectral states of neutron-star and black-hole XRBs, and there is general agreement about the type of the accretion disk around the compact object in the various spectral states. Our aim is to investigate whether the phenomenology regarding the X-ray emission on one hand and the jet appearance and disappearance on the other can be put...

Kylafis, N D; Kazanas, D; Christodoulou, D M

2011-01-01T23:59:59.000Z

218

Compact x-ray source and panel  

SciTech Connect

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

219

An X-ray Reprocessing Model of Disk Thermal Emission in Type 1 Seyfert Galaxies  

E-Print Network (OSTI)

Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, & Ryde for the X-ray binary Cygnus X-1 and later applied to Seyfert galaxies by Zdziarski, Lubi\\'nski, & Smith, feedback between the radiation reprocessed by the disk and the thermal Comptonization emission from the hot central plasma plays a pivotal role in determining the X-ray spectrum, and as we show, the optical and ultraviolet spectra as well. Seemingly uncorrelated optical/UV and X-ray light curves, similar to those which have been observed from these objects can be explained by variations in the size, shape, and temperature of the Comptonizing plasma. Furthermore, by positing a disk mass accretion rate which satisfies a condition for global energy balance between the thermal Comptonization luminosity and the power available from accretion, one can predict the spectral properties of the hard X-ray continuum above $\\sim 50$ keV in type 1 Seyfert galaxies. Forthcoming measurements of the hard X-ray continuum by more sensitive hard X-ray and soft $\\gamma$-ray telescopes, in conjunction with simultaneous optical, UV, and soft X-ray monitoring, will allow the mass accretion rates to be directly constrained for these sources in the context of this model.

James Chiang

2002-02-12T23:59:59.000Z

220

X-ray Time Lags in TeV Blazars  

E-Print Network (OSTI)

We use Monte Carlo/Fokker-Planck simulations to study the X-ray time lags. Our results show that soft lags will be observed as long as the decay of the flare is dominated by radiative cooling, even when acceleration and cooling timescales are similar. Hard lags can be produced in presence of a competitive achromatic particle energy loss mechanism if the acceleration process operates on a timescale such that particles are slowly moved towards higher energy while the flare evolves. In this type of scenario, the {\\gamma} -ray/X-ray quadratic relation is also reproduced.

Chen, Xuhui; Liang, Edison; Bttcher, Markus

2011-01-01T23:59:59.000Z

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

Angular Correlations of the X-Ray Background and Clustering of Extragalactic X-Ray Sources  

E-Print Network (OSTI)

The information content of the autocorrelation function (ACF) of intensity fluctuations of the X-ray background (XRB) is analyzed. The tight upper limits set by ROSAT deep survey data on the ACF at arcmin scales imply strong constraints on clustering properties of X-ray sources at cosmological distances and on their contribution to the soft XRB. If quasars have a clustering radius r_0=12-20 Mpc (H_0=50), and their two point correlation function, is constant in comoving coordinates as indicated by optical data, they cannot make up more 40-50% of the soft XRB (the maximum contribution may reach 80% in the case of stable clustering, epsilon=0). Active Star-forming (ASF) galaxies clustered like normal galaxies, with r_0=10-12 Mpc can yield up to 20% or up to 40% of the soft XRB for epsilon=-1.2 or epsilon=0, respectively. The ACF on degree scales essentially reflects the clustering properties of local sources and is proportional to their volume emissivity. The upper limits on scales of a few degrees imply that hard X-ray selected AGNs have r_06 deg, if real, may be due to AGNs with r_0=20 Mpc; the contribution from clusters of galaxies with r_0~50 Mpc is a factor 2 lower.

L. Danese; L. Toffolatti; A. Franceschini; J. M. Martin-Mirones; G. De Zotti

1993-02-24T23:59:59.000Z

222

X-ray Synchrotron Radiation in a Plasma Wiggler  

SciTech Connect

A relativistic electron beam can radiate due to its betatron motion inside an ion channel. The ion channel is induced by the electron bunch as it propagates through an underdense plasma. In the theory section of this thesis the formation of the ion channel, the trajectories of beam electrons inside the ion channel, the radiation power and the radiation spectrum of the spontaneous emission are studied. The comparison between different plasma wiggler schemes is made. The difficulties in realizing stimulated emission as the beam traverses the ion channel are investigated, with particular emphasis on the bunching mechanism, which is important for the ion channel free electron laser. This thesis reports an experiment conducted at the Stanford Linear Accelerator Center (SLAC) to measure the betatron X-ray radiations for the first time. They first describe the construction and characterization of the lithium plasma source. In the experiment, the transverse oscillations of the SLAC 28.5 GeV electron beam traversing through a 1.4 meter long lithium plasma source are clearly seen. These oscillations lead to a quadratic density dependence of the spontaneously emitted betatron X-ray radiation. The divergence angle of the X-ray radiation is measured. The absolute photon yield and the spectral brightness at 14.2 KeV photon energy are estimated and seen to be in reasonable agreement with theory.

Wang, Shuoquin; /UCLA /SLAC, SSRL

2005-09-27T23:59:59.000Z

223

An X-ray photometry system I: Chandra ACIS  

E-Print Network (OSTI)

We present a system of X-ray photometry for the Chandra satellite. X-ray photometry can be a powerful tool to obtain flux estimates, hardness ratios, and colors unbiased by assumptions about spectral shape and independent of temporal and spatial changes in instrument characteristics. The system we have developed relies on our knowledge of effective area and the energy-to-channel conversion to construct filters similar to photometric filters in the optical bandpass. We show that the filters are well behaved functions of energy and that this X-ray photometric system is able to reconstruct fluxes to within about 20%, without color corrections, for non-pathological spectra. Even in the worst cases it is better than 50%. Our method also treats errors in a consistent manner, both statistical as well as systematic.

Grimm, H -J; Fabbiano, G; Elvis, M

2008-01-01T23:59:59.000Z

224

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

225

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

DOE Green Energy (OSTI)

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

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

2003-01-27T23:59:59.000Z

226

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

227

Tokamak physics studies using x-ray diagnostic methods  

SciTech Connect

X-ray diagnostic measurements have been used in a number of experiments to improve our understanding of important tokamak physics issues. The impurity content in TFTR plasmas, its sources and control have been clarified through soft x-ray pulse-height analysis (PHA) measurements. The dependence of intrinsic impurity concentrations and Z/sub eff/ on electron density, plasma current, limiter material and conditioning, and neutral-beam power have shown that the limiter is an important source of metal impurities. Neoclassical-like impurity peaking following hydrogen pellet injection into Alcator C and a strong effect of impurities on sawtooth behavior were demonstrated by x-ray imaging (XIS) measurements. Rapid inward motion of impurities and continuation of m = 1 activity following an internal disruption were demonstrated with XIS measurements on PLT using injected aluminum to enhance the signals. Ion temperatures up to 12 keV and a toroidal plasma rotation velocity up to 6 x 10/sup 5/ m/s have been measured by an x-ray crystal spectrometer (XCS) with up to 13 MW of 85-keV neutral-beam injection in TFTR. Precise wavelengths and relative intensities of x-ray lines in several helium-like ions and neon-like ions of silver have been measured in TFTR and PLT by the XCS. The data help to identify the important excitation processes predicted in atomic physics. Wavelengths of n = 3 to 2 silver lines of interest for x-ray lasers were measured, and precise instrument calibration techniques were developed. Electron thermal conductivity and sawtooth dynamics have been studied through XIS measurements on TFTR of heat-pulse propagation and compound sawteeth. A non-Maxwellian electron distribution function has been measured, and evidence of the Parail-Pogutse instability identified by hard x-ray PHA measurements on PLT during lower-hybrid current-drive experiments.

Hill, K.W.; Bitter, M.; von Goeler, S.; Beiersdorfer, P.; Fredrickson, E.; Hsuan, H.; McGuire, K.; Sauthoff, N.R.; Sesnic, S.; Stevens, J.E.

1987-03-01T23:59:59.000Z

228

Chest x-Rays | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

229

Spectral analysis of X-ray binaries  

E-Print Network (OSTI)

In this thesis, I present work from three separate research projects associated with observations of X-ray binaries. Two of those revolve around spectral characteristics of neutron star low-mass X-ray binaries (NS-LMXBs), ...

Fridriksson, Joel Karl

2011-01-01T23:59:59.000Z

230

Free-Electron Lasers: Present Status and Future Prospects  

E-Print Network (OSTI)

38,892 (1977). C. Brau, "Free-Electron Lasers", Science 239,115 (1988). T. Marshall, "Free-Electron Lasers", MacMillan (1985); C Brau, "Free- Electron Lasers", Academic Press (

Kim, K.-J.

2008-01-01T23:59:59.000Z

231

Cryotomography x-ray microscopy state  

Science Conference Proceedings (OSTI)

An x-ray microscope stage enables alignment of a sample about a rotation axis to enable three dimensional tomographic imaging of the sample using an x-ray microscope. A heat exchanger assembly provides cooled gas to a sample during x-ray microscopic imaging.

Le Gros, Mark (Berkeley, CA); Larabell, Carolyn A. (Berkeley, CA)

2010-10-26T23:59:59.000Z

232

Kinematics of Compton backscattering x-ray source for angiography  

SciTech Connect

Calculations of X-Ray production rates, energy spread, and spectrum of Compton-backscattered photons from a Free Electron Laser on an electron beam in a low energy (136-MeV) compact (8.5-m circumference) storage ring indicate that an X-Ray intensity of 34.6 10{sup 7} X-Ray photons per 0.5-mm {times} 0.5-mm pixel for Coronary Angiography near the 33.169-keV iodine K-absorption edge can be achieved in a 4-msec pulse within a scattering cone of 1-mrad half angle. This intensity, at 10-m from the photon-electron interaction point to the patient is about a factor of 10 larger than presently achieved from a 4.5-T superconducting wiggler source in the NSLS 2.5-GeV storage ring and over an area about 5 times larger. The 2.2-keV energy spread of the Compton-backscattered beam is, however, much larger than the 70-eV spread presently attained form the wiggler source and use of a monochromator. The beam spot at the 10-m interaction point-to-patient distance is 20-mm diameter; larger spots are attainable at larger distances but with a corresponding reduction in X-Ray flux. Such a facility could be an inexpensive clinical alternative to present methods of non-invasive Digital Subtraction Angiography (DSA), small enough to be deployed in an urban medical center, and could have other medical, industrial and aerospace applications. Problems with the Compton backscattering source include laser beam heating of the mirror in the FEL oscillator optical cavity, achieving a large enough X-Ray beam spot at the patient, and obtaining radiation damping of the transverse oscillations and longitudinal emittance dilution of the storage ring electron beam resulting from photon-electron collisions without going to higher electron energy where the X-Ray energy spread becomes excessive for DSA. 38 refs.

Blumberg, L.N.

1992-05-01T23:59:59.000Z

233

X-ray spectral states of microquasars  

E-Print Network (OSTI)

We discuss the origin of the dramatically different X-ray spectral shapes observed in the Low Hard State (LHS: dominated by thermal comptonisation) and the High Soft State (HSS: dominated by the accretion disc thermal emission and non-thermal comptonisation in the corona). We present numerical simulations using a new code accounting for the so-called synchrotron boiler effect. These numerical simulations when compared to the data allow us to constrain the magnetic field and temperature of the hot protons in the corona. For the hard state of Cygnus X-1 we find a magnetic field below equipartition with radiation, suggesting that the corona is not powered through magnetic field dissipation (as assumed in most accretion disc corona models). On the other hand, our results also point toward proton temperatures that are substantially lower than typical temperatures of the ADAF models. Finally, we show that in both spectral states Comptonising plasma could be powered essentially through power-law acceleration of non-thermal electrons, which are then partly thermalised by the synchrotron and Coulomb boiler. This suggests that, contrary to current beliefs, the corona of the HSS and that of the LHS could be of very similar nature. The differences between the LHS and HSS coronal spectra would then be predominantly caused by the strong disc soft cooling emission which is present in the HSS and absent in the LHS.

Julien Malzac; Renaud Belmont

2008-10-25T23:59:59.000Z

234

Soft X-Ray Thomson Scattering in Warm Dense Hydrogen at FLASH  

DOE Green Energy (OSTI)

We present collective Thomson scattering with soft x-ray free electron laser radiation as a method to track the evolution of warm dense matter plasmas with {approx}200 fs time resolution. In a pump-probe scheme an 800 nm laser heats a 20 {micro}m hydrogen droplet to the plasma state. After a variable time delay in the order of ps the plasma is probed by an x-ray ultra violet (XUV) pulse which scatters from the target and is recorded spectrally. Alternatively, in a self-Thomson scattering experiment, a single XUV pulse heats the target while a portion of its photons are being scattered probing the target. From such inelastic x-ray scattering spectra free electron temperature and density can be inferred giving insight on relaxation time scales in plasmas as well as the equation of state. We prove the feasibility of this method in the XUV range utilizing the free electron laser facility in Hamburg, FLASH. We recorded Thomson scattering spectra for hydrogen plasma, both in the self-scattering and in the pump-probe mode using optical laser heating.

Faustlin, R R; Toleikis, S; Bornath, T; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gode, S; Gregori, G; Irsig, R; Laarmann, T; Lee, H J; Li, B; Meiwes-Broer, K; Mithen, J; Przystawik, A; Redlin, H; Redmer, R; Reinholz, H; Ropke, G; Tavella, F; Thiele, R; Tiggesbaumker, J; Uschmann, I; Zastrau, U; Tschentscher, T

2009-07-15T23:59:59.000Z

235

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

236

Correlated Optical/X-ray Long-term Variability in LMXB 4U1636-536  

E-Print Network (OSTI)

We have conducted a 3-month program of simultaneous optical, soft and hard X-ray monitoring of the LMXB 4U1636-536/V801 Ara using the SMARTS 1.3m telescope and archival RXTE/ASM and Swift/XRT data. 4U1636-536 has been exhibiting a large amplitude, quasi-periodic variability since 2002 when its X-ray flux dramatically declined by roughly an order of magnitude. We confirmed that the anti-correlation between soft (2-12 keV) and hard (> 20 keV) X-rays, first investigated by Shih et al. (2005), is not an isolated event but a fundamental characteristic of this source's variability properties. However, the variability itself is neither strictly stable nor changing on an even longer characteristic timescale. We also demonstrate that the optical counterpart varies on the same timescale, and is correlated with the soft, and not the hard, X-rays. This clearly shows that X-ray reprocessing in LMXB discs is mainly driven by soft X-rays. The X-ray spectra in different epochs of the variability revealed a change of spectral...

Shih, I C; Cornelisse, R

2010-01-01T23:59:59.000Z

237

Transverse Coherence of the LCLS X-Ray Beam  

Science Conference Proceedings (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

238

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

NLE Websites -- All DOE Office Websites (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

239

Theme Article - Time-Resolved X-Ray Scattering from Coherent Excitations in Solids  

SciTech Connect

Recent advances in pulsed x-ray sources have opened up new opportunities to study the dynamics of matter directly in the time domain with picosecond to femtosecond resolution. In this article, we present recent results from a variety of ultrafast sources on time-resolved x-ray scattering from elementary excitations in periodic solids. A few representative examples are given on folded acoustic phonons, coherent optical phonons, squeezed phonons, and polaritons excited by femtosecond lasers. Next-generation light sources, such as the x-ray-free electron laser, will lead to improvements in coherence, flux, and pulse duration. These experiments demonstrate potential opportunities for studying matter far from equilibrium on the fastest time scales and shortest distances that will be available in the coming years.

Trigo, Mariano; Reis, David (SLAC)

2010-10-22T23:59:59.000Z

240

Ultrafast time dynamics studies of periodic lattices with free electron laser radiation  

Science Conference Proceedings (OSTI)

It has been proposed that radiation from free electron laser (FEL) at Hamburg (FLASH) can be used for ultrafast time-resolved x-ray diffraction experiments based on the near-infrared (NIR) pump/FEL probe scheme. Here, investigation probing the ultrafast structural dynamics of periodic nano-crystalline organic matter (silver behenate) with such a scheme is reported. Excitation with a femtosecond NIR laser leads to an ultrafast lattice modification which time evolution has been studied through the scattering of vacuum ultraviolet FEL pulses. The found effect last for 6 ps and underpins the possibility for studying nanoperiodic dynamics down to the FEL source time resolution. Furthermore, the possibility of extending the use of silver behenate (AgBh) as a wavelength and temporal calibration tool for experiments with soft x-ray/FEL sources is suggested.

Quevedo, W.; Busse, G.; Hallmann, J.; More, R.; Petri, M.; Rajkovic, I. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany); Krasniqi, F.; Rudenko, A. [Max Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg (Germany); Tschentscher, T. [European XFEL GmbH, Albert-Einstein-Ring 19, 22671 Hamburg (Germany); Stojanovic, N.; Duesterer, S.; Treusch, R.; Tolkiehn, M. [HASYLAB at DESY, Notkestrasse 85, 22607 Hamburg (Germany); Techert, S. [Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen (Germany); Max Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg (Germany)

2012-11-01T23:59:59.000Z

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

Unifying disc-jet behaviour in X-ray binaries: an optical/IR approach  

E-Print Network (OSTI)

Synchrotron emission from jets produced by X-ray binaries can be detected at optical and infrared (IR) frequencies. I show that optical/IR colour-magnitude diagrams of the outbursts of nine X-ray binaries successfully separate thermal disc emission from non-thermal jet emission, in both black hole and neutron star sources. A heated single-temperature blackbody is able to reproduce the observed relations between colour and magnitude, except when excursions are made to a redder colour than expected, which is due to jet emission. The general picture that is developed is then incorporated into the unified picture of disc-jet behaviour in black hole X-ray binaries. At a given position of a source in the X-ray hardness-intensity diagram, the radio, IR and optical properties can be inferred. Similarly, it is possible to predict the X-ray and radio luminosities and spectral states from optical/IR monitoring.

David M. Russell; Dipankar Maitra; Rob P. Fender; Fraser Lewis

2008-11-18T23:59:59.000Z

242

X-ray data booklet. Revision  

SciTech Connect

A compilation of data is presented. Included are properties of the elements, electron binding energies, characteristic x-ray energies, fluorescence yields for K and L shells, Auger energies, energy levels for hydrogen-, helium-, and neonlike ions, scattering factors and mass absorption coefficients, and transmission bands of selected filters. Also included are selected reprints on scattering processes, x-ray sources, optics, x-ray detectors, and synchrotron radiation facilities. (WRF)

Vaughan, D. (ed.)

1986-04-01T23:59:59.000Z

243

X-ray transmissive debris shield  

DOE Patents (OSTI)

A composite window structure is described for transmitting x-ray radiation and for shielding radiation generated debris. In particular, separate layers of different x-ray transmissive materials are laminated together to form a high strength, x-ray transmissive debris shield which is particularly suited for use in high energy fluences. In one embodiment, the composite window comprises alternating layers of beryllium and a thermoset polymer.

Spielman, Rick B. (Albuquerque, NM)

1994-01-01T23:59:59.000Z

244

NIST X-Ray Transition Energies  

Science Conference Proceedings (OSTI)

... with the International System of measurement ... titled "X-ray transition energies: new approach ... and by NIST's Systems Integration for Manufacturing ...

2011-12-09T23:59:59.000Z

245

X-ray Line Profile Analysis  

Science Conference Proceedings (OSTI)

... Magnetic Composite Materials X-Ray Studies of Structural Effects Induced by Pulsed (30 Tesla), High Magnetic Fields at the Advanced Photon Source...

246

NIST: X-Ray Mass Attenuation Coefficients  

Science Conference Proceedings (OSTI)

... NIST reserves the right to charge for these data in the ... ?/? and the mass energy-absorption coefficient ... The tables cover energies of the photon (x-ray ...

2011-12-09T23:59:59.000Z

247

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (Extended Search)

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...

248

X-ray pulse preserving single-shot optical cross-correlation method for improved experimental temporal resolution  

Science Conference Proceedings (OSTI)

We measured the relative arrival time between an optical pulse and a soft x-ray pulse from a free-electron laser. This femtosecond cross-correlation measurement was achieved by observing the change in optical reflectivity induced through the absorption of a fraction of the x-ray pulse. The main x-ray pulse energy remained available for an independent pump-probe experiment where the sample may be opaque to soft x-rays. The method was employed to correct the two-pulse delay data from a canonical pump-probe experiment and demonstrate 130 {+-} 20 fs (FWHM) temporal resolution. We further analyze possible timing jitter sources and point to future improvements.

Beye, M. [SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, 12489 Berlin (Germany); Krupin, O. [LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); European XFEL GmbH, 22607 Hamburg (Germany); Hays, G.; Jong, S. de; Lee, S.; Coffee, R.; Holmes, M. R.; Fry, A. R.; White, W. E.; Bostedt, C.; Schlotter, W. F. [LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Reid, A. H. [SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Radboud University Nijmegen, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands); Rupp, D. [Technische Universitaet Berlin, 10623 Berlin (Germany); LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Lee, W.-S.; Scherz, A. O. [SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Chuang, Y.-D. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Cryan, J. P.; Glownia, J. M. [PULSE, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Foehlisch, A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, 12489 Berlin (Germany); Durr, H. A. [SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

2012-03-19T23:59:59.000Z

249

X?ray Fluorescence (XRF) Assay Using Laser Compton Scattered (LCS) X?rays  

Science Conference Proceedings (OSTI)

Laser Compton Scattered (LCS) X?rays are produced as a result of the interaction between accelerated electrons and a laser beam. The yield of LCS X?rays is dependent on the laser power

Syed F. Naeem; Khalid Chouffani; Douglas P. Wells

2009-01-01T23:59:59.000Z

250

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

251

X-Ray Multilayer Database from the LBL Center for X-Ray Optics (CXRO)  

DOE Data Explorer (OSTI)

An important activity of the Center for X-ray Optics (CXRO) is research on x-ray mirrors and their use in optical devices to focus and deflect x-ray beams. The two kinds of mirrors most widely used are glancing incidence reflectors and multilayer coatings. The X-Ray Multilayer Database is based on the results of surveys taken at the biennial Physics of X-Ray Multilayer Structures conferences. It contains measured x-ray reflectances reported for various multilayers. The database is provided as a service to the x-ray and multilayer research communities and is intended to reflect the state-of-the-art in multilayer x-ray mirrors. (Specialized Interface)

252

Materials Analysis by Soft x-ray Scanning Transmission X-ray ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Optical and X-ray Imaging Techniques for Material Characterization.

253

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

NLE Websites -- All DOE Office Websites (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.

254

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

NLE Websites -- All DOE Office Websites (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.

255

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

NLE Websites -- All DOE Office Websites (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.

256

Free electron laser designs for laser amplification  

DOE Patents (OSTI)

Method for laser beam amplification by means of free electron laser techniques. With wiggler magnetic field strength B.sub.w and wavelength .lambda..sub.w =2.pi./k.sub.w regarded as variable parameters, the method(s) impose conditions such as substantial constancy of B.sub.w /k.sub.w or k.sub.w or B.sub.w and k.sub.w (alternating), coupled with a choice of either constant resonant phase angle or programmed phase space "bucket" area.

Prosnitz, Donald (Walnut Creek, CA); Szoke, Abraham (Fremont, CA)

1985-01-01T23:59:59.000Z

257

Free electron laser with masked chicane  

DOE Patents (OSTI)

A free electron laser (FEL) is provided with an accelerator for outputting electron beam pulses; a buncher for modulating each one of the electron beam pulses to form each pulse into longitudinally dispersed bunches of electrons; and a wiggler for generating coherent light from the longitudinally dispersed bunches of electrons. The electron beam buncher is a chicane having a mask for physically modulating the electron beam pulses to form a series of electron beam bunches for input to the wiggler. In a preferred embodiment, the mask is located in the chicane at a position where each electron beam pulse has a maximum dispersion.

Nguyen, Dinh C. (Los Alamos, NM); Carlsten, Bruce E. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

258

X-RAY VARIABILITY AND EVIDENCE FOR PULSATIONS FROM THE UNIQUE RADIO PULSAR/X-RAY BINARY TRANSITION OBJECT FIRST J102347.6+003841  

Science Conference Proceedings (OSTI)

We report on observations of the unusual neutron-star binary system FIRST J102347.6+003841 carried out using the XMM-Newton satellite. This system consists of a radio millisecond pulsar (PSR J1023+0038) in a 0.198 day orbit with a {approx}0.2 M{sub sun} Roche-lobe-filling companion and appears to have had an accretion disk in 2001. We observe a hard power-law spectrum ({Gamma} = 1.26(4)) with a possible thermal component, and orbital variability in X-ray flux and possibly hardness of the X-rays. We also detect probable pulsations at the pulsar period (single-trial significance {approx}4.5{sigma} from an 11(2)% modulation), which would make this the first system in which both orbital and rotational X-ray pulsations are detected. We interpret the emission as a combination of X-rays from the pulsar itself and from a shock where material overflowing the companion meets the pulsar wind. The similarity of this X-ray emission to that seen from other millisecond pulsar binary systems, in particular 47 Tuc W (PSR J0024 - 7204W) and PSR J1740 - 5340, suggests that they may also undergo disk episodes similar to that seen in J1023 in 2001.

Archibald, Anne M.; Kaspi, Victoria M.; Bogdanov, Slavko [Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Hessels, Jason W. T. [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands); Stairs, Ingrid H. [Department of Physics and Astronomy, 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); McLaughlin, Maura A., E-mail: aarchiba@physics.mcgill.c [Department of Physics, West Virginia University, Morgantown, WV 26505 (United States)

2010-10-10T23:59:59.000Z

259

BROADBAND SPECTRAL ANALYSIS OF THE GALACTIC RIDGE X-RAY EMISSION  

SciTech Connect

Detailed spectral analysis of the Galactic X-ray background emission, or the Galactic Ridge X-ray Emission (GRXE), is presented. To study the origin of the emission, broadband and high-quality GRXE spectra were produced from 18 pointing observations with Suzaku in the Galactic bulge region, with a total exposure of 1 Ms. The spectra were successfully fitted by a sum of two major spectral components: a spectral model of magnetic accreting white dwarfs with a mass of 0.66{sup +0.09}{sub -0.07} M{sub Sun} and a softer optically thin thermal emission with a plasma temperature of 1.2-1.5 keV that is attributable to coronal X-ray sources. When combined with previous studies that employed high spatial resolution of the Chandra satellite, the present spectroscopic result gives stronger support to the scenario that the GRXE is essentially an assembly of numerous discrete faint X-ray stars. The detected GRXE flux in the hard X-ray band was used to estimate the number density of the unresolved hard X-ray sources. When integrated over a luminosity range of {approx}10{sup 30}-10{sup 34} erg s{sup -1}, the result is consistent with a value that was reported previously by directly resolving faint point sources.

Yuasa, Takayuki; Makishima, Kazuo; Nakazawa, Kazuhiro, E-mail: yuasa@astro.isas.jaxa.jp [Department of Physics, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan)

2012-07-10T23:59:59.000Z

260

Airborne Tactical Free-Electron Laser  

Science Conference Proceedings (OSTI)

The goal of 100 kilowatts (kW) of directed energy from an airborne tactical platform has proved challenging due to the size and weight of most of the options that have been considered. However, recent advances in Free-Electron Lasers appear to offer a solution along with significant tactical advantages: a nearly unlimited magazine, time structures for periods from milliseconds to hours, radar like functionality, and the choice of the wavelength of light that best meets mission requirements. For an Airborne Tactical Free-Electron Laser (ATFEL) on a platforms such as a Lockheed C-130J-30 and airships, the two most challenging requirements, weight and size, can be met by generating the light at a higher harmonic, aggressively managing magnet weights, managing cryogenic heat loads using recent SRF R&D results, and using FEL super compact design concepts that greatly reduce the number of components. The initial R&D roadmap for achieving an ATFEL is provided in this paper. Performing this R&D is expected to further reduce the weight, size and power requirements for the FELs the Navy is currently developing for shipboard applications, as well as providing performance enhancements for the strategic airborne MW class FELs. The 100 kW ATFEL with its tactical advantages may prove sufficiently attractive for early advancement in the queue of deployed FELs.

Roy Whitney; George Neil

2007-02-01T23:59:59.000Z

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

APS Bending Magnet X-rays and  

NLE Websites -- All DOE Office Websites (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

262

High-Resolution X-ray Spectroscopy  

Science Conference Proceedings (OSTI)

... In support of these efforts, we also maintain laboratory x-ray sources from 1 keV to 300 keV, energy and intensity calibration facilities, and a vacuum ...

2013-02-26T23:59:59.000Z

263

X-ray image intensifier phosphor  

DOE Patents (OSTI)

Y/sub 1-x/Gd/sub x/.PO$sub 4$:Tb$sup 3+$ is an effective phosphor for use in X-ray intensifier screens and in nuclear radiation detection systems.

D' Silva, A.P.; Fassel, V.A.

1975-12-01T23:59:59.000Z

264

Kaonic Atom X?ray Spectra  

Science Conference Proceedings (OSTI)

In kaonic atoms energy displacement and broadening of states result from the strong interaction. The most simple kaonic atoms like kaonic hydrogen and deuterium open the possibility to measure this strong interaction induced shift and width by x?ray spectroscopy. In the SIDDHARTA experiment al LNF (Frascati) the DA?NE electron?positron collider delivers nearly mono?energetic negatively charged kaons from ? meson decay. This unique kaon source is used to form kaonic atoms. New high performance x?ray detectors (silicon drift detectors) arranged in an array allow x?ray spectroscopy with high energy resolution combined with timing capability. High precision x?ray measurements like SIDDHARTA at LNF will open the way to study the low energy regime of the strong force in the antikaon?nucleon interaction. The experiment and its current status is presented in this talk.

J. Marton; on behalf of the SIDDHARTA Collaboration

2009-01-01T23:59:59.000Z

265

X-ray grid-detector apparatus  

DOE Patents (OSTI)

A hybrid grid-detector apparatus for x-ray systems wherein a microchannel plate structure has an air-interspaced grid portion and a phosphor/optical fluid-filled grid portion. The grids are defined by multiple adjacent channels separated by lead-glass septa. X-rays entering the air-interspaced grid portion at an angle of impingement upon the septa are attenuated, while non-impinging x-rays pass through to the phosphor/fluid filled portion. X-ray energy is converted to luminescent energy in the phosphor/fluid filled portion and the resultant beams of light are directed out of the phosphor/optical fluid filled portion to an imaging device.

Boone, John M. (Folsom, CA); Lane, Stephen M. (Oakland, CA)

1998-01-27T23:59:59.000Z

266

X-Ray Nanoimaging: Instruments and Methods  

NLE Websites -- All DOE Office Websites (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...

267

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

- Brookhaven National Laboratory, Upton, NY Beamline X1A2 - Soft x-ray diffraction and nano-imaging Beamline X17 - X-ray powder diffraction Beamline X22C - Resonant x-ray...

268

Accelerator Design Study for a Soft X-Ray Free Electron Laser at the Lawrence Berkeley National Laboratory  

E-Print Network (OSTI)

and Phase Diagnostics, SLAC Report LCLS-TN-00-12. Emma P.al. 2009, First Results of the LCLS Laser-Heater System, PACLinac Coherent Light Source (LCLS) Conceptual Design Report,

Kur, E.

2010-01-01T23:59:59.000Z

269

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

NLE Websites -- All DOE Office Websites (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.

270

X-Ray Emission from Compact Sources  

SciTech Connect

This paper presents a review of the physical parameters of neutron stars and black holes that have been derived from X-ray observations. I then explain how these physical parameters can be used to learn about the extreme conditions occurring in regions of strong gravity, and present some recent evidence for relativistic effects seen in these systems. A glossary of commonly used terms and a short tutorial on the names of X-ray sources are also included.

Cominsky, L

2004-03-23T23:59:59.000Z

271

Compton backscattered collimated x-ray source  

SciTech Connect

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

272

Compton backscattered collmated X-ray source  

SciTech Connect

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

273

Argonne TDC: Hard X-Ray Scanning Microprobe  

2000 R&D 100 Award Winner! With suboptical spatial resolution, the microprobe offers unprecedented benefits via quantitative elemental, chemical, structural, and ...

274

Towards In Situ Hard X-ray Microscopy of Photovoltaic  

Science Conference Proceedings (OSTI)

Photovoltaic systems for energy generation are at the core of efforts to ... solar cells and models that represent the evolution of impurities during cell processing.

275

Materials Characterization Using the Hard X-Ray Nanoprobe ...  

Science Conference Proceedings (OSTI)

In full-field transmission mode, the sample is illuminated using a capillary condenser system; a magnified image of the sample with a spatial resolution of 30 nm...

276

Argonne TDC: Advanced Photon Source's Hard X-Ray Scanning ...  

... zinc proteins or enzymes, copper in chromatin, iron in macrophages) or from an external source (e.g., in anticancer drugs such as cisplatin, ...

277

Photon Sciences | Beamlines | CHX: Coherent Hard X-ray Scattering...  

NLE Websites -- All DOE Office Websites (Extended Search)

exceeding, for a photon energy near E8 keV, 1021 phsmrad2mm20.1 % bw (more than one order of magnitude higher than that of the Advanced Photon Source), the CHX beamline will...

278

Copper Ridges Nearly Double X-ray Sensor Performance  

Science Conference Proceedings (OSTI)

... Physics Letters,* can measure X-ray energies with an ... X-rays and measure the energy based on ... by NASA and the NIST Office of Microelectronics ...

2011-10-03T23:59:59.000Z

279

Sandia National Laboratories X-ray Tube with Magnetic Electron ...  

... for the U.S. Department of Energys National ... high average power large area X-ray tube provides increased X-ray generation efficiency through ...

280

Inelastic X-ray and Nuclear Resonant Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Beamlines Divisions Argonne Home > Advanced Photon Source > Inelastic X-ray and Nuclear Resonant Scattering The Inelastic X-ray and Nuclear Resonant Scattering group...

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

Electron beam-based sources of ultrashort x-ray pulses.  

Science Conference Proceedings (OSTI)

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. The importance of the time-resolved studies of matter at picosecond (ps), femtosecond (fs), and atttosecond (as) time scales using x-rays has been widely recognized including by award of a Nobel Prize in 1999 [Zewa]. Extensive reviews of scientific drivers can be found in [BES1, BES2, BES3, Lawr, Whit]. Several laser-based techniques have been used to generate ultrashort x-ray pulses including laser-driven plasmas [Murn, Alte, Risc, Rose, Zamp], high-order harmonic generation [Schn, Rund, Wang, Arpi], and laser-driven anode sources [Ande]. In addition, ultrafast streak-camera detectors have been applied at synchrotron sources to achieve temporal resolution on the picosecond time scale [Wulf, Lind1]. In this paper, we focus on a different group of techniques that are based on the use of the relativistic electron beam produced in conventional accelerators. In the first part we review several techniques that utilize spontaneous emission of electrons and show how solitary sub-ps x-ray pulses can be obtained at existing storage ring based synchrotron light sources and linacs. In the second part we consider coherent emission of electrons in the free-electron lasers (FELs) and review several techniques for a generation of solitary sub-fs x-ray pulses. Remarkably, the x-ray pulses that can be obtained with the FELs are not only significantly shorter than the ones considered in Part 1, but also carry more photons per pulse by many orders of magnitude.

Zholents, A.; Accelerator Systems Division (APS)

2010-09-30T23:59:59.000Z

282

Transient x-ray diffraction and its application to materials science and x-ray optics  

SciTech Connect

Time resolved x-ray diffraction and scattering have been applied to the measurement of a wide variety of physical phenomena from chemical reactions to shock wave physics. Interest in this method has heightened in recent years with the advent of versatile, high power, pulsed x-ray sources utilizing laser plasmas, electron beams and other methods. In this article, we will describe some of the fundamentals involved in time resolved x-ray diffraction, review some of the history of its development, and describe some recent progress in the field. In this article we will emphasize the use of laser-plasmas as the x-ray source for transient diffraction.

Hauer, A.A.; Kopp, R.; Cobble, J.; Kyrala, G.; Springer, R. [and others

1997-12-01T23:59:59.000Z

283

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

284

Short pulse free electron laser amplifier  

DOE Patents (OSTI)

Method and apparatus for amplification of a laser pulse in a free electron laser amplifier where the laser pulse duration may be a small fraction of the electron beam pulse duration used for amplification. An electron beam pulse is passed through a first wiggler magnet and a short laser pulse to be amplified is passed through the same wiggler so that only the energy of the last fraction, f, (f<1) of the electron beam pulse is consumed in amplifying the laser pulse. After suitable delay of the electron beam, the process is repeated in a second wiggler magnet, a third, . . . , where substantially the same fraction f of the remainder of the electron beam pulse is consumed in amplification of the given short laser pulse in each wiggler magnet region until the useful electron beam energy is substantially completely consumed by amplification of the laser pulse.

Schlitt, Leland G. (Livermore, CA); Szoke, Abraham (Fremont, CA)

1985-01-01T23:59:59.000Z

285

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 T{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.

1998-04-21T23:59:59.000Z

286

X-ray Thomson scattering for partially ionized plasmas including the effect of bound levels  

E-Print Network (OSTI)

X-ray Thomson scattering is being developed as a method to measure the temperature, electron density, and ionization state of high energy density plasmas such as those used in inertial confinement fusion. Most experiments are currently done at large laser facilities that can create bright X-ray sources, however the advent of the X-ray free electron laser (X-FEL) provides a new bright source to use in these experiments. One challenge with X-ray Thomson scattering experiments is understanding how to model the scattering for partially ionized plasmas in order to include the contributions of the bound electrons in the scattered intensity. In this work we take the existing models of Thomson scattering that include elastic ion-ion scattering and the electron-electron plasmon scattering and add the contribution of the bound electrons in the partially ionized plasmas. We validated our model by analyzing existing beryllium experimental data. We then consider several higher Z materials such as Cr and predict the existe...

Nilsen, J; Cheng, K T

2013-01-01T23:59:59.000Z

287

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

Science Conference Proceedings (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.

2011-08-16T23:59:59.000Z

288

Real-Space x-ray tomographic reconstruction of randomly oriented objects with sparse data frames  

E-Print Network (OSTI)

Schemes for X-ray imaging single protein molecules using new x-ray sources, like x-ray free electron lasers (XFELs), require processing many frames of data that are obtained by taking temporally short snapshots of identical molecules, each with a random and unknown orientation. Due to the small size of the molecules and short exposure times, average signal levels of much less than 1 photon/pixel/frame are expected, much too low to be processed using standard methods. One approach to process the data is to use statistical methods developed in the EMC algorithm (Loh & Elser, Phys. Rev. E, 2009) which processes the data set as a whole. In this paper we apply this method to a real-space tomographic reconstruction using sparse frames of data (below $10^{-2}$ photons/pixel/frame) obtained by performing x-ray transmission measurements of a low-contrast, randomly-oriented object. This extends the work by Philipp et al. (Optics Express, 2012) to three dimensions and is one step closer to the single molecule recons...

Ayyer, Kartik; Tate, Mark W; Elser, Veit; Gruner, Sol M

2013-01-01T23:59:59.000Z

289

Radiographic X-Ray Pulse Jitter  

Science Conference Proceedings (OSTI)

The Dual Beam Radiographic Facility consists of two identical radiographic sources. Major components of the machines are: Marx generator, water-filled pulse-forming line (PFL), water-filled coaxial transmission line, three-cell inductive voltage adder, and rod-pinch diode. The diode pulse has the following electrical specifications: 2.25-MV, 60-kA, 60-ns. Each source has the following x-ray parameters: 1-mm-diameter spot size, 4-rad at 1 m, 50-ns full width half max. The x-ray pulse is measured with PIN diode detectors. The sources were developed to produce high resolution images on single-shot, high-value experiments. For this application it is desirable to maintain a high level of reproducibility in source output. X-ray pulse jitter is a key metric for analysis of reproducibility. We will give measurements of x-ray jitter for each machine. It is expected that x-ray pulse jitter is predominantly due to PFL switch jitter, and therefore a correlation of the two will be discussed.

Mitton, C. V., Good, D. E., Henderson, D. J., Hogge, K. W.

2011-01-15T23:59:59.000Z

290

X-Ray Data from the X-Ray Data Booklet Online  

DOE Data Explorer (OSTI)

The original X-Ray Data Booklet, published in 1985, became a classic reference source. The online version has been significantly revised and updated to reflect today's science. Hundreds of pages of authoritative data provide the x-ray properties of elements, information on synchrotron radiation, scattering processes, optics and detectors, and other related calculations, formulas, and data tables.

Thompson, Albert C.; Attwood, David T.; Gullikson, Eric M.; Howells, Malcolm R.; Kortright, Jeffrey B.; Robinson, Arthur L.; Underwood, James H.; Kim, Kwang-Je; Kirz, Janos; Lindau, Ingolf; Pianetta, Piero; Winick, Herman; Williams, Gwyn P.; Scofield, James H.

291

Technical Report on DOE project: X-ray physics of materials (proposal No.Z817)  

SciTech Connect

The SRI-CAT was able to order the construction of the First Optics Enclosure, the second enclosure housing the monochromator and the first user station, and various motors, controllers, and electronics for the control of the hard x-ray beamline components.

Colella, Roberto; Durbin, Stephen

2001-01-01T23:59:59.000Z

292

Radiobiological studies using gamma and x rays.  

Science Conference Proceedings (OSTI)

There are approximately 500 self-shielded research irradiators used in various facilities throughout the U.S. These facilities use radioactive sources containing either 137Cs or 60Co for a variety of biological investigations. A report from the National Academy of Sciences[1] described the issues with security of particular radiation sources and the desire for their replacement. The participants in this effort prepared two peer-reviewed publications to document the results of radiobiological studies performed using photons from 320-kV x rays and 137Cs on cell cultures and mice. The effectiveness of X rays was shown to vary with cell type.

Potter, Charles Augustus; Longley, Susan W.; Scott, Bobby R. [Lovelace Respiratory Research Institute, Albuquerque, NM; Lin, Yong [Lovelace Respiratory Research Institute, Albuquerque, NM; Wilder, Julie [Lovelace Respiratory Research Institute, Albuquerque, NM; Hutt, Julie A. [Lovelace Respiratory Research Institute, Albuquerque, NM; Padilla, Mabel T. [Lovelace Respiratory Research Institute, Albuquerque, NM; Gott, Katherine M. [Lovelace Respiratory Research Institute, Albuquerque, NM

2013-02-01T23:59:59.000Z

293

X-ray Science Division: Groups  

NLE Websites -- All DOE Office Websites (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

294

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

295

FURTHER EVIDENCE THAT QUASAR X-RAY EMITTING REGIONS ARE COMPACT: X-RAY AND OPTICAL MICROLENSING IN THE LENSED QUASAR Q J0158-4325  

Science Conference Proceedings (OSTI)

We present four new seasons of optical monitoring data and six epochs of X-ray photometry for the doubly imaged lensed quasar Q J0158-4325. The high-amplitude, short-period microlensing variability for which this system is known has historically precluded a time delay measurement by conventional methods. We attempt to circumvent this limitation by the application of a Monte Carlo microlensing analysis technique, but we are only able to prove that the delay must have the expected sign (image A leads image B). Despite our failure to robustly measure the time delay, we successfully model the microlensing at optical and X-ray wavelengths to find a half-light radius for soft X-ray emission log (r{sub 1/2,X,soft}/cm) = 14.3{sup +0.4}{sub -0.5}, an upper limit on the half-light radius for hard X-ray emission log (r{sub 1/2,X,hard}/cm) {<=} 14.6, and a refined estimate of the inclination-corrected scale radius of the optical R-band (rest frame 3100 A) continuum emission region of log (r{sub s} /cm) = 15.6 {+-} 0.3.

Morgan, Christopher W.; Hainline, Laura J. [Department of Physics, United States Naval Academy, 572C Holloway Road, Annapolis, MD 21402 (United States); Chen Bin; Dai Xinyu [Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States); Tewes, Malte; Courbin, F.; Meylan, G. [Laboratoire d'Astrophysique, Ecole Polytechnique Federale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Kochanek, Christopher S.; Kozlowski, Szymon; Blackburne, Jeffrey A.; Mosquera, Ana M. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210-1173 (United States); Chartas, G. [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States)

2012-09-01T23:59:59.000Z

296

Analysis of Coherence Properties of 3-rd Generation Synchrotron Sources and Free-Electron Lasers  

E-Print Network (OSTI)

A general theoretical approach based on the results of statistical optics is used for the analysis of the transverse coherence properties of 3-rd generation synchrotron sources and x-ray free-electron lasers (XFEL). Correlation properties of the wavefields are calculated at different distances from an equivalent Gaussian Schell-model source. This model is used to describe coherence properties of the five meter undulator source at the synchrotron storage ring PETRA III. In the case of XFEL sources the decomposition of the statistical fields into a sum of independently propagating transverse modes is used for the analysis of the coherence properties of these new sources. A detailed calculation is performed for the parameters of the SASE1 undulator at the European XFEL. It is demonstrated that only a few modes contribute significantly to the total radiation field of that source.

Vartanyants, I A

2009-01-01T23:59:59.000Z

297

OPTICAL TO X-RAY SUPERNOVA LIGHT CURVES FOLLOWING SHOCK BREAKOUT THROUGH A THICK WIND  

Science Conference Proceedings (OSTI)

Recent supernova (SN) observations have motivated renewed interest in SN shock breakouts from stars surrounded by thick winds. In such events the interaction with the wind powers the observed luminosity, and predictions include observable hard X-rays. Wind breakouts on timescales of a day or longer are currently the most probable for detection. Here, we study the signal that follows such events. We start from the breakout of the radiation-mediated shock, finding that the breakout temperature can vary significantly from one event to another (10{sup 4} to 5 Multiplication-Sign 10{sup 6} K) due to possible deviation from thermal equilibrium. In general, events with longer breakout pulse duration, t {sub bo}, are softer. We follow the observed radiation through the evolution of the collisionless shock that forms after the breakout of the radiation-mediated shock. We restrict the study of the collisionless shock evolution to cases where the breakout itself is in thermal equilibrium, peaking in optical/UV. In these cases the post-breakout emission contains two spectral components-soft (optical/UV) and hard (X-rays and possibly soft {gamma}-rays). Right after the breakout pulse X-rays are strongly suppressed, and they carry only a small fraction of the total luminosity. The hard component becomes harder, and its luminosity rises quickly afterward, gaining dominance at {approx}10-50 t {sub bo}. The ratio of the peak optical/UV to the peak X-ray luminosity depends mostly on the breakout time. In early breakouts (t {sub bo} {approx} 80 days for typical parameters) the X-rays become dominant only after the total luminosity has dropped significantly. In terms of prospects for X-ray and soft gamma-ray detections, it is best to observe 100-500 days after explosions with breakout timescales between a week and a month.

Svirski, Gilad; Nakar, Ehud [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Sari, Re'em [Racah Institute for Physics, Hebrew University, Jerusalem 91904 (Israel)

2012-11-10T23:59:59.000Z

298

The Soft-X-Ray Spectral Shape of X-Ray-Weak Seyferts  

E-Print Network (OSTI)

(I) We observed eight Seyfert~2s and two X--ray--weak Seyfert~1/QSOs with the ROSAT PSPC, and one Seyfert~2 with the ROSAT HRI. These targets were selected from the Extended 12\\um\\ Galaxy Sample. (II) Both Seyfert~1/QSOs vary by factors of 1.5---2. The photon indices steepen in the more luminous state, consistent with the variability being mainly due to the softest X--rays, which are confined to a size of less than a parsec. (III) Both the Seyfert~2s and Seyfert~1/QSOs are best fit with a photon index of $\\Gamma\\sim3$, which is steeper than the canonical value of $\\Gamma\\sim1.7$ measured for X--ray--strong Seyferts by ROSAT and at higher energies. Several physical explanations are suggested for the steeper slopes of X--ray--weak objects. (IV) We observed one Seyfert~2, NGC~5005, with the ROSAT HRI, finding about 13\\% of the soft X--rays to come from an extended component. This and other observations suggest that different components to the soft X--ray spectrum of some, if not all, X--ray--weak Seyferts may come from spatially distinct regions.

Brian Rush; Matthew A. Malkan

1995-07-27T23:59:59.000Z

299

Multiple wavelength x-ray monochromators  

DOE Patents (OSTI)

An 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 second 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 focussing the separate first and second output x-ray radiation wavelengths into separate focal points.

Steinmeyer, P.A.

1991-01-01T23:59:59.000Z

300

Multiple wavelength x-ray monochromators  

DOE Patents (OSTI)

An 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 second 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 focussing the separate first and second output x-ray radiation wavelengths into separate focal points.

Steinmeyer, P.A.

1991-12-31T23:59:59.000Z

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

Massively parallel X-ray scattering simulations  

Science Conference Proceedings (OSTI)

Although present X-ray scattering techniques can provide tremendous information on the nano-structural properties of materials that are valuable in the design and fabrication of energy-relevant nano-devices, a primary challenge remains in the analyses ...

Abhinav Sarje; Xiaoye S. Li; Slim Chourou; Elaine R. Chan; Alexander Hexemer

2012-11-01T23:59:59.000Z

302

X-Ray and Neutron Diffraction  

Science Conference Proceedings (OSTI)

Oct 20, 2010 ... Advanced X-Ray Scattering Techniques for Multi-Length Scale ... ?-Ti using the 3DXRD station 34-ID-E at the Advanced Photon Source, Argonne National Laboratory. ... Research at APS 34-ID-E, partly funded by BES/DOE.

303

Soft x-ray laser microscope  

Science Conference Proceedings (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

304

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

305

Deducing the Orientation of the Semimajor Axis of the Eta Carinae Binary System from X-ray Observations  

E-Print Network (OSTI)

We study the usage of the X-ray light curve, column density toward the hard X-ray source, and emission measure (density square times volume), of the massive binary system Eta Carinae to determine the orientation of its semi-major axis. The source of the hard X-ray emission is the shocked secondary wind. We argue that, by itself, the observed X-ray flux cannot teach us much about the orientation of the semi-major axis. Minor adjustment of some unknown parameters of the binary system allows to fit theX-ray light curve with almost any inclination angle and orientation. The column density and X-ray emission measure, on the other hand, impose strong constrains on the orientation. We improve our previous calculations and show that the column density is more compatible with an orientation where for most of the time the secondary - the hotter, less massive star - is behind the primary star. The secondary comes closer to the observer only for a short time near periastron passage. The ten-week X-ray deep minimum, which...

Soker, Amit Kashi Noam

2009-01-01T23:59:59.000Z

306

Evaluation of the sensitivity and fading characteristics of an image plate system for x-ray diagnostics  

SciTech Connect

Image plates (IPs) are a reusable recording media capable of detecting ionizing radiation, used to diagnose x-ray emission from laser-plasma experiments. Due to their superior performance characteristics in x-ray applications [C. C. Bradford, W. W. Peppler, and J. T. Dobbins III, Med. Phys. 26, 27 (1999) and J. Digit. Imaging. 12, 54 (1999)], the Fuji Biological Analysis System (BAS) IPs are fielded on x-ray diagnostics for the HELEN laser by the Plasma Physics Department at AWE. The sensitivities of the Fuji BAS IPs have been absolutely calibrated for absolute measurements of x-ray intensity in the energy range of 0-100 keV. In addition, the Fuji BAS IP fading as a function of time was investigated. We report on the characterization of three Fuji BAS IP responses to x-rays using a radioactive source, and discrete x-ray line energies generated by the Excalibur soft x-ray facility and the Defense Radiological Standards Centre filter-fluorescer hard x-ray system at AWE.

Meadowcroft, A. L.; Bentley, C. D.; Stott, E. N. [Plasma Physics Department, AWE Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom)

2008-11-15T23:59:59.000Z

307

X-Ray Interactions with Matter  

DOE Data Explorer (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. (Taken from the abstract in OSTI Record 6131765) (Specialized Interface)

Henke, B.L.; Gullikson, E.M.; Davis, J.C.

308

Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser  

SciTech Connect

An amplitude and phase compensation system has been developed and tested at the University of Hawai'i for the optimization of the RF drive system to the Mark V free-electron laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with the results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.

Hadmack, M. R.; Kowalczyk, J. M. D.; Lienert, B. R.; Madey, J. M. J.; Szarmes, E. B. [Department of Physics and Astronomy, University of Hawai'i at Manoa, Honolulu, Hawaii 96822 (United States); Jacobson, B. T. [RadiaBeam Technologies, Santa Monica, California 90404 (United States)

2013-06-15T23:59:59.000Z

309

Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser  

E-Print Network (OSTI)

An amplitude and phase compensation system has been developed and tested at the University of Hawai`i for the optimization of the RF drive system to the Mark V Free-Electron Laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with the results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.

Hadmack, M R; Kowalczyk, J M D; Lienert, B R; Madey, J M J; Szarmes, E B

2013-01-01T23:59:59.000Z

310

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

Science Conference Proceedings (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

311

Bruker Workshop on Single Crystal X-Ray Diffraction  

NLE Websites -- All DOE Office Websites (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

312

Rise time measurement for ultrafast X-ray pulses  

Science Conference Proceedings (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. (Berkeley, CA); Weber, Franz A. (Oakland, CA); Moon, Stephen J. (Tracy, CA)

2005-04-05T23:59:59.000Z

313

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

314

X-ray Thomson scattering measurements from shock-compressed deuterium  

Science Conference Proceedings (OSTI)

X-ray Thomson scattering has recently been shown to be an effective method of diagnosing a variety of high energy density plasma conditions. We apply this powerful technique to the widely studied problem of shock-compressed liquid deuterium. The behavior of deuterium under extreme conditions has received considerable attention due to its central role in models of giant planets and the importance of the high-pressure insulator-metal transition. We have used spectrally resolved x-ray scattering from electron-plasma waves to perform microscopic observations of ionization during compression. In these experiments, a single shock was launched in cryogenic deuterium reaching compressions of 3x. The 2 keV Ly-{alpha} line in silicon was used as an x-ray source in a forward scattering geometry. In addition to elastic scattering from tightly bound electrons, this low probe energy accessed the collective plasmon oscillations of delocalized electrons. Inelastic scattering from the plasmons allowed accurate measurements of the free electron density through the spectral position of the resonance and provided an estimate of the temperature through its ratio with the elastic feature. Combined with velocity interferometry from the reflective shock front, this lead to a direct determination of the ionization state. We compare the measured ionization conditions with computational models. Additionally, we discuss the possibility of using this technique to determine electrical conductivity and to directly observe pressure-induced molecular dissociation along the Hugoniot.

Davis, P.; Doeppner, T.; Rygg, J. R.; Fortmann, C.; Unites, W.; Salmonson, J.; Collins, G. W.; Landen, O. L.; Falcone, R. W.; Glenzer, S. H. [University of California, Berkeley. Berkeley, CA, 94720 (United States); Lawrence Livermore National Laboratory. Livermore, CA 94551 (United States); University of California, Berkeley. Berkeley, CA, 94720 (United States)

2012-05-25T23:59:59.000Z

315

Dynamics and rheology under continuous shear flow studied by X-ray photon correlation spectroscopy  

E-Print Network (OSTI)

X-ray Photon Correlation Spectroscopy (XPCS) has emerged as a unique technique allowing the measurement of dynamics in materials on mesoscopic lengthscales. In particular, applications in soft matter physics cover a broad range of topics which include, but are not limited to, nanostructured materials such as colloidal suspensions or polymers, dynamics at liquid surfaces, membranes and interfaces, and the glass or gel transition. One of the most common problems associated with the use of bright X-ray beams with soft materials is beam induced radiation damage, and this is likely to become an even more limiting factor at future synchrotron and free electron laser sources. Flowing the sample during data acquisition is one of the simplest method allowing to limit the radiation damage. In addition to distributing the dose over many different scatterers, the method also enables new functionalities such as time-resolved studies in mixing cells. Here, we further develop an experimental technique that was recently proposed combining XPCS and continuously flowing samples. More specifically, we use a model system to show how the macroscopic advective response to flow and the microscopic dissipative dynamics (diffusion) can be quantified from the X-ray data. The method has many potential applications, e.g. dynamics of glasses and gels under continuous shear/flow, protein aggregations processes, the interplay between dynamics and rheology in complex fluids.

Andrei Fluerasu; Pawel Kwasniewski; Chiara Caronna; Fanny Destremaut; Jean-Baptiste Salmon; Anders Madsen

2010-01-10T23:59:59.000Z

316

Design of a triaxial residual stress measurement system using high energy x-ray diffraction  

Science Conference Proceedings (OSTI)

Previous design studies in developing concepts for residual stress measurement in engineering materials have been extended. A pre-prototype energy dispersive x-ray diffraction (EDXRD) system has been fabricated. A 300 kV radiography source is used in conjunction with an intrinsic germanium detector and a MacII/LabVIEW data acquisition system. Specimens up to 25mm equivalent steel thickness (and one meter gross dimensions) can now be evaluated. The pre-prototype system serves as the hard x-ray, bulk stress measurement component of the previously reported hybrid stress measuring system (which would include a traditional multi-angle surface measurement system using soft x-rays). In addition, a detailed study of residual stress analytical equations has been completed and applied to various metallic and ceramic materials. During the grant period, related studies were completed on stress measurement using synchrotron radiation and on a critical review of the residual stress literature. 6 refs., 3 figs.

Shackelford, J.F.; Brown, B.D.; Park, J.S.

1989-01-01T23:59:59.000Z

317

In Situ X-Ray Probing Reveals Fingerprints of Surface Platinum Oxide  

DOE Green Energy (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

318

Microscale X-ray Absorption Spectroscopy on the GSECARS Sector 13 at the APS  

E-Print Network (OSTI)

GeoSoilEnviroCARS (GSECARS) is a national user facility for frontier research in the earth sciences using synchrotrons radiation at the Advanced Photon Source, Argonne National Laboratory. GSECARS provides earth scientists with access to the high-brilliance hard x-rays from this third-generation synchrotrons light source. The research conducted at this facility will advance our knowledge of the composition, structure and properties of earth materials, the processes they control and the processes that produce them. All principal synchrotron-based analytical techniques in demand by earth scientists are being brought to bear on earth science problems: (1) high-pressure/high-temperature crystallography and spectroscopy using the diamond anvil cell; (2) high-pressure/high-temperature crystallography using the large-volume press; (3) powder, single crystal and interface diffraction; (4) x-ray absorption fine structure (XAFS) spectroscopy; (5) x-ray fluorescence microprobe analysis and microspectroscopy; and (6) mic...

Stephen-Sutto

2000-01-01T23:59:59.000Z

319

In situ X-ray Characterization of Energy Storage Materials | Stanford  

NLE Websites -- All DOE Office Websites (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

320

X-ray flashes and X-ray rich gamma ray bursts. Memorie della Societa Astronomica Italiana  

E-Print Network (OSTI)

Abstract. X-ray flashes are detected in the Wide Field Cameras on BeppoSAX in the energy range 2-25 keV as bright X-ray sources lasting of the order of minutes, but remaining undetected in the Gamma Ray Bursts Monitor on BeppoSAX. They have properties very similar to the x-ray counterparts of GRBs and account for some of the Fast X-ray Transient events seen in almost every x-ray satellite. We review their X-ray properties and show that x-ray flashes are in fact very soft, x-ray rich, untriggered gamma ray bursts, in which the peak energy in 2-10 keV x-rays could be up to a factor of 100 larger than the peak energy in the 50-300 keV gamma ray range. The frequency is ? 100 yr ?1. 1 Fast X-ray Transients/High-latitude X-ray Transients Fast X-ray Transients have been observed with many x-ray satellites. In particular they are seen with x-ray instruments that scan the entire sky on a regular basis. Such events are detected in one sky scan and disappeared in the next, typically limiting the duration to be longer than a minute and shorter than a few hours. For this reason they are called Fast Transients. The first transients

John Heise; Jean In t Z; Peter M. Woods

2001-01-01T23:59:59.000Z

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.


321

SLAC National Accelerator Laboratory - X-ray Laser Helps Fight...  

NLE Websites -- All DOE Office Websites (Extended Search)

human health. "This is the first new biological structure solved with a free-electron laser," said Henry Chapman of the Center for Free-Electron Laser Science in Hamburg,...

322

X-rays Illuminate Ancient Archimedes Text  

NLE Websites -- All DOE Office Websites (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,

323

HIGH BRILLIANCE X-RAY SCATTERING FOR  

NLE Websites -- All DOE Office Websites (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-

324

High resolution x-ray microscope  

Science Conference Proceedings (OSTI)

The authors present x-ray images of grid meshes and biological material obtained using a microspot x-ray tube with a multilayer optic and a 92-element parabolic compound refractive lens (CRL) made of a plastic containing only hydrogen and carbon. Images obtained using this apparatus are compared with those using an area source with a spherical lens and a spherical lens with multilayer condenser. The authors found the best image quality using the multilayer condenser with a parabolic lens, compared to images with a spherical lens and without the multilayer optics. The resolution was measured using a 155-element parabolic CRL and a multilayer condenser with the microspot tube. The experiment demonstrates about 1.1 {mu}m resolution.

Gary, C. K.; Park, H.; Lombardo, L. W.; Piestrup, M. A.; Cremer, J. T.; Pantell, R. H.; Dudchik, Y. I. [Adelphi Technology, Inc. 981-B Industrial Road, San Carlos, California 94070 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Institute of Applied Physics Problems, Kurchatova 7, Minsk 220064 (Belarus)

2007-04-30T23:59:59.000Z

325

IDENTIFICATION OF GALACTIC BULGE SURVEY X-RAY SOURCES WITH TYCHO-2 STARS  

Science Conference Proceedings (OSTI)

We identify 69 X-ray sources discovered by the Galactic Bulge Survey (GBS) that are coincident with or very close to bright stars in the Tycho-2 catalog. Additionally, two other GBS sources are resolved binary companions to Tycho-2 stars where both components are separately detected in X-rays. Most of these are likely to be real matches, but we identify nine objects with large and significant X-ray-to-optical offsets as either detections of resolved binary companions or chance alignments. We collate known spectral types for these objects, and also examine Two Micron All Sky Survey colors, variability information from the All-Sky Automated Survey, and X-ray hardness ratios for the brightest objects. Nearly a third of the stars are found to be optically variable, divided roughly evenly between irregular variations and periodic modulations. All fall among the softest objects identified by the GBS. The sample forms a very mixed selection, ranging in spectral class from O9 to M3. In some cases, the X-ray emission appears consistent with normal coronal emission from late-type stars, or wind emission from early-types, but the sample also includes one known Algol, one W UMa system, two Be stars, and several X-ray bright objects likely to be coronally active stars or binaries. Surprisingly, a substantial fraction of the spectroscopically classified, non-coincidental sample (12 out of 38 objects) have late B or A type counterparts. Many of these exhibit redder near-IR colors than expected for their spectral type and/or variability, and it is likely that the X-rays originate from a late-type companion star in most or all of these objects.

Hynes, Robert I.; Britt, C. T. [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Tower Drive, Baton Rouge, LA 70803 (United States); Wright, N. J.; Jonker, P. G.; Steeghs, D.; Torres, M. A. P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Maccarone, T. J. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Greiss, S. [Astronomy and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Nelemans, G., E-mail: rih@phys.lsu.edu [Department of Astrophysics, IMAPP, Radboud University Nijmegen, Heyendaalseweg 135, 6525-AJ Nijmegen (Netherlands)

2012-12-20T23:59:59.000Z

326

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, V.L.

1991-12-31T23:59:59.000Z

327

TENDER ENERGY X-RAY ABSORPTION  

NLE Websites -- All DOE Office Websites (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

328

A kpc-scale X-ray jet in the BL Lac source S5 2007+777  

E-Print Network (OSTI)

X-ray jets in AGN are commonly observed in FRII and FRI radio-galaxies, but rarely in BL Lacs, most probably due to their orientation close to the line of sight and the ensuing foreshortening effects. Only three BL Lacs are known so far to contain a kpc-scale X-ray jet. In this paper, we present the evidence for the existence of a fourth extended X-ray jet in the classical radio-selected source S5 2007+777, which for its hybrid FRI/II radio morphology has been classified as a HYMOR (HYbrid MOrphology Radio source). Our Chandra ACIS-S observations of this source revealed an X-ray counterpart to the 19"-long radio jet. Interestingly, the X-ray properties of the kpc-scale jet in S5 2007+777 are very similar to those observed in FRII jets. First, the X-ray morphology closely mirrors the radio one, with the X-rays being concentrated in the discrete radio knots. Second, the X-ray continuum of the jet/brightest knot is described by a very hard power law, with photon index Gamma_x~1, although the uncertainties are large. Third, the optical upper limit from archival HST data implies a concave radio-to-X-ray SED. If the X-ray emission is attributed to IC/CMB with equipartition, strong beaming (delta=13) is required, implying a very large scale (Mpc) jet. The beaming requirement can be somewhat relaxed assuming a magnetic field lower than equipartition. Alternatively, synchrotron emission from a second population of very high-energy electrons is viable. Comparison to other HYMOR jets detected with Chandra is discussed, as well as general implications for the origin of the FRI/II division.

Rita M. Sambruna; Davide Donato; C. C. Cheung; F. Tavecchio; L. Maraschi

2008-05-07T23:59:59.000Z

329

Ignition feedback regenerative free electron laser (FEL) amplifier  

Science Conference Proceedings (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

330

THE CHANDRA X-RAY SURVEY OF PLANETARY NEBULAE (CHANPLANS): PROBING BINARITY, MAGNETIC FIELDS, AND WIND COLLISIONS  

Science Conference Proceedings (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

331

Energy Determination of X-Ray Transition Energies Using the ...  

Science Conference Proceedings (OSTI)

... We chose to measure x-ray transition energies from NIST ... This resulted in the production of x-ray emission ... would yield not only an energy scale for ...

2012-10-02T23:59:59.000Z

332

SLAC National Accelerator Laboratory - SLAC's X-ray Laser Explores...  

NLE Websites -- All DOE Office Websites (Extended Search)

X-ray Laser Explores Big Data Frontier By Glenn Roberts Jr. June 12, 2013 It's no surprise that the data systems for SLAC's Linac Coherent Light Source X-ray laser have drawn...

333

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (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...

334

SLAC National Accelerator Laboratory - SLAC X-rays Help Discover...  

NLE Websites -- All DOE Office Websites (Extended Search)

which pulses 120 times a second. In the instant before the intense X-rays destroy a nanocrystal, detectors record a flash of X-ray diffraction information. Finally, scientists use...

335

Using Light to Control How X Rays Interact with Matter  

NLE Websites -- All DOE Office Websites (Extended Search)

Using Light to Control How X Rays Interact with Matter Using Light to Control How X Rays Interact with Matter Print Wednesday, 27 January 2010 00:00 Schemes that use one light...

336

Microstructural Mapping Using High-Energy X-Ray Scattering  

Science Conference Proceedings (OSTI)

Abstract Scope, Advanced characterization methods at the APS permit unique in- situ ... The combination of an undulator source, brilliance preserving optics and focusing .... Ultra-Small-Angle X-Ray ScatteringX-Ray Photon Correlation...

337

Strengthened lithium for x-ray blast windows  

Science Conference Proceedings (OSTI)

Lithium's high x-ray transparency makes it an attractive material for windows intended to protect soft x-ray diagnostics in high energy density experiments. Pure lithium is soft and weak, but lithium mixed with lithium hydride powder becomes harder and stronger, in principle without any additional x-ray absorption. A comparison with the standard material for x-ray windows, beryllium, suggests that lithium or lithium strengthened by lithium hydride may well be an excellent option for such windows.

Pereira, N. R. [Ecopulse Inc., P.O. Box 528, Springfield, Virginia 22150 (United States); Imam, M. A. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2008-05-15T23:59:59.000Z

338

Electron and X-Ray Microscopy: Structural Characterization of ...  

Science Conference Proceedings (OSTI)

Oct 28, 2009 ... Recent Advances in Structural Characterization of Materials: Electron and X-Ray Microscopy: Structural Characterization of Nanoscale...

339

X-ray Microscopy and Imaging: 2-BM  

NLE Websites -- All DOE Office Websites (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.

340

Wiggler plane focusing in a linear free electron laser  

DOE Patents (OSTI)

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, Ernst T. (Livermore, CA)

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.


341

Free electron laser using Rf coupled accelerating and decelerating structures  

DOE Patents (OSTI)

A free electron laser and free electron laser amplifier using beam transport devices for guiding an electron beam to a wiggler of a free electron laser and returning the electron beam to decelerating cavities disposed adjacent to the accelerating cavities of the free electron laser. Rf energy is generated from the energy depleted electron beam after it emerges from the wiggler by means of the decelerating cavities which are closely coupled to the accelerating cavities, or by means of a second bore within a single set of cavities. Rf energy generated from the decelerated electron beam is used to supplement energy provided by an external source, such as a klystron, to thereby enhance overall efficiency of the system.

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

1984-01-01T23:59:59.000Z

342

Quantitative Analysis of Mt. St. Helens Ash by X-Ray Diffraction and X-Ray Fluorescence Spectrometry  

Science Conference Proceedings (OSTI)

A quantitative study by x-ray diffraction, optical polarizing microscopy, and x-ray fluorescence spectrometry of fallout and ambient ash from three Mt. St. Helens eruptions has revealed a consistent picture of the mineralogical and elemental ...

Briant L. Davis; L. Ronald Johnson; Dana T. Griffen; William Revell Phillips; Robert K. Stevens; David Maughan

1981-08-01T23:59:59.000Z

343

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

344

GRB 070724B: the first Gamma Ray Burst localized by SuperAGILE and its Swift X-ray Afterglow  

E-Print Network (OSTI)

GRB 070724B is the first Gamma Ray Burst localized by SuperAGILE, the hard X-ray monitor aboard the AGILE satellite. The coordinates of the event were published $\\sim 19$ hours after the trigger. The Swift X-Ray Telescope pointed at the SuperAGILE location and detected the X-ray afterglow inside the SuperAGILE error circle. The AGILE gamma-ray Tracker and Minicalorimeter did not detect any significant gamma ray emission associated with GRB 070724B in the MeV and GeV range, neither prompt nor delayed. Searches of the optical afterglow were performed by the Swift UVOT and the Palomar automated 60-inch telescopes without any significant detection. Similarly the Very Large Array did not detect a radio afterglow. This is the first GRB event with a firm upper limit in the 100 MeV -- 30 GeV energy range, associated with an X-ray afterglow.

E. Del Monte; M. Feroci; L. Pacciani; Y. Evangelista; I. Donnarumma; P. Soffitta; E. Costa; I. Lapshov; F. Lazzarotto; M. Rapisarda; A. Argan; G. Barbiellini; M. Basset; A. Bulgarelli; P. Caraveo; A. Chen; G. Di Cocco; L. Foggetta; F. Fuschino; M. Galli; F. Gianotti; A. Giuliani; C. Labanti; P. Lipari; F. Longo; M. Marisaldi; F. Mauri; S. Mereghetti; A. Morselli; A. Pellizzoni; F. Perotti; P. Picozza; M. Prest; G. Pucella; M. Tavani; M. Trifoglio; A. Trois; E. Vallazza; S. Vercellone; V. Vittorini; A. Zambra; P. Romano; D. N. Burrows; G. Chincarini; N. Gehrels; V. La Parola; P. T. O'Brien; J. P. Osborne; B. Preger; C. Pittori; L. A. Antonelli; F. Verrecchia; P. Giommi; L. Salotti

2007-12-04T23:59:59.000Z

345

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 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

346

Ultra-Short Electron Bunch and X-Ray Temporal Diagnostics with an X-Band Transverse Deflector  

Science Conference Proceedings (OSTI)

The measurement of ultra-short electron bunches on the femtosecond time scale constitutes a very challenging problem. In X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS), generation of sub-ten femtosecond X-ray pulses is possible, and some efforts have been put into both ultra-short electron and X-ray beam diagnostics. Here we propose a single-shot method using a transverse rf deflector (X-band) after the undulator to reconstruct both the electron bunch and X-ray temporal profiles. Simulation studies show that about 1 fs (rms) time resolution may be achievable in the LCLS and is applicable to a wide range of FEL wavelengths and pulse lengths. The jitter, resolution and other related issues will be discussed. The successful operation of the Linac Coherent Light Source (LCLS), with its capability of generating free-electron laser (FEL) X-ray pulses from a few femtoseconds (fs) up to a few hundred fs, opens up vast opportunities for studying atoms and molecules on this unprecedented ultrashort time scale. However, tremendous challenges remain in the measurement and control of these ultrashort pulses with femtosecond precision, for both the electron beam (e-beam) and the X-ray pulses. For ultrashort e-beam bunch length measurements, a standard method has been established at LCLS using an S-band radio-frequency (rf) deflector, which works like a streak camera for electrons and is capable of resolving bunch lengths as short as {approx} 10 fs rms. However, the e-beam with low charges of 20 pC at LCLS, which is expected to be less than 10 fs in duration, is too short to be measured using this transverse deflector. The measurement of the electron bunch length is helpful in estimating the FEL X-ray pulse duration. However, for a realistic beam, such as that with a Gaussian shape or even a spiky profile, the FEL amplification varies along the bunch due to peak current or emittance variation. This will cause differences between the temporal shape or duration of the electron bunch and the X-ray pulse. Initial experiments at LCLS have revealed that characterization of the X-ray pulse duration on a shot-by-shot basis is critical for the interpretation of the data. However, a reliable x-ray pulse temporal diagnostic tool is not available so far at the LCLS. We propose a novel method in this paper to characterize the FEL X-ray pulse duration and shape. A transverse rf deflector is used in conjunction with an e-beam energy spectrometer, located after the FEL undulator. By measuring the difference in the e-beam longitudinal phase space between FEL-on and FEL-off, we can obtain the time-resolved energy loss and energy spread induced from the FEL radiation, allowing the FEL X-ray temporal shape to be reconstructed.

Ding, Y.; Emma, P.; Frisch, J.; Huang, Z.; Loos, H.; Krejcik, P.; Wang, M-H.; /SLAC; Behrens, C.; /DESY

2011-12-13T23:59:59.000Z

347

Calibrating X-ray Imaging Devices for Accurate Intensity Measurement  

SciTech Connect

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

348

THE NUCLEAR SPECTROSCOPIC TELESCOPE ARRAY (NuSTAR) HIGH-ENERGY X-RAY MISSION  

SciTech Connect

The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3 to 79 keV, extending the sensitivity of focusing far beyond the {approx}10 keV high-energy cutoff achieved by all previous X-ray satellites. The inherently low background associated with concentrating the X-ray light enables NuSTAR to probe the hard X-ray sky with a more than 100-fold improvement in sensitivity over the collimated or coded mask instruments that have operated in this bandpass. Using its unprecedented combination of sensitivity and spatial and spectral resolution, NuSTAR will pursue five primary scientific objectives: (1) probe obscured active galactic nucleus (AGN) activity out to the peak epoch of galaxy assembly in the universe (at z {approx}< 2) by surveying selected regions of the sky; (2) study the population of hard X-ray-emitting compact objects in the Galaxy by mapping the central regions of the Milky Way; (3) study the non-thermal radiation in young supernova remnants, both the hard X-ray continuum and the emission from the radioactive element {sup 44}Ti; (4) observe blazars contemporaneously with ground-based radio, optical, and TeV telescopes, as well as with Fermi and Swift, to constrain the structure of AGN jets; and (5) observe line and continuum emission from core-collapse supernovae in the Local Group, and from nearby Type Ia events, to constrain explosion models. During its baseline two-year mission, NuSTAR will also undertake a broad program of targeted observations. The observatory consists of two co-aligned grazing-incidence X-ray telescopes pointed at celestial targets by a three-axis stabilized spacecraft. Deployed into a 600 km, near-circular, 6 Degree-Sign inclination orbit, the observatory has now completed commissioning, and is performing consistent with pre-launch expectations. NuSTAR is now executing its primary science mission, and with an expected orbit lifetime of 10 yr, we anticipate proposing a guest investigator program, to begin in late 2014.

Harrison, Fiona A.; Cook, W. Rick; Forster, Karl; Grefenstette, Brian W.; Madsen, Kristin K.; Mao, Peter H.; Miyasaka, Hiromasa [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Craig, William W.; Pivovaroff, Michael J. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, Charles J.; Koglin, Jason E.; Mori, Kaya [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Zhang, William W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Boggs, Steven E. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Stern, Daniel; Kim, Yunjin [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Giommi, Paolo; Perri, Matteo [ASI Science Data Center, c/o ESRIN, via G. Galilei, I-00044 Frascati (Italy); Kitaguchi, Takao, E-mail: fiona@srl.caltech.edu [INAF-Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio (Italy); and others

2013-06-20T23:59:59.000Z

349

Apparatus for monitoring x-ray beam alignment  

DOE Patents (OSTI)

A self-contained, hand-held apparatus is provided for monitoring 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, P.A.

1989-09-12T23:59:59.000Z

350

Direct detection of x-rays for protein crystallography  

DOE Patents (OSTI)

An apparatus and method for directly determining the crystalline structure of a protein crystal. The crystal is irradiated by a finely collimated x-ray beam. The interaction o f the x-ray beam with the crystal produces scattered x-rays. These scattered x-rays are detected by means of a large area, thick CCD which is capable of measuring a significant number of scattered x-rays which impact its surface. The CCD is capable of detecting the position of impact of the scattered x-ray on the surface of the CCD and the quantity of scattered x-rays which impact the same cell or pixel. This data is then processed in real-time and the processed data is outputted to produce an image of the structure of the crystal. If this crystal is a protein the molecular structure of the protein can be determined from the data received.

Atac, Muzaffer; McKay, Timothy

1997-12-01T23:59:59.000Z

351

Introduction to Neutron and X-Ray Scattering  

NLE Websites -- All DOE Office Websites (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.

352

FREE ELECTRON LASERS FOR THE PRODUCTION OF INFRARED AND MILLIMETER WAVES  

E-Print Network (OSTI)

S.M. Gold, et. al. , in Free Electron Generators of CoherentThe Hughes Low-Voltage Free-Electron Laser Program," inProc. of the 1985 Free Electron Laser Conference, Lake

Sessler, A.M.

2008-01-01T23:59:59.000Z

353

Free-electron laser driven by the LBNL laser-plasma accelerator  

E-Print Network (OSTI)

Free-electron laser driven by the LBNL laser-plasmaA design of a compact free-electron laser (FEL), generatingare considered. Keywords: Free-electron laser, laser-plasma

Schroeder, C. B.

2010-01-01T23:59:59.000Z

354

Absolute x-ray energy calibration over a wide energy range using a diffraction-based iterative method  

SciTech Connect

In this paper, we report a method of precise and fast absolute x-ray energy calibration over a wide energy range using an iterative x-ray diffraction based method. Although accurate x-ray energy calibration is indispensable for x-ray energy-sensitive scattering and diffraction experiments, there is still a lack of effective methods to precisely calibrate energy over a wide range, especially when normal transmission monitoring is not an option and complicated micro-focusing optics are fixed in place. It is found that by using an iterative algorithm the x-ray energy is only tied to the relative offset of sample-to-detector distance, which can be readily varied with high precision of the order of 10{sup -5}-10{sup -6} spatial resolution using gauge blocks. Even starting with arbitrary initial values of 0.1 A, 0.3 A, and 0.4 A, the iteration process converges to a value within 3.5 eV for 31.122 keV x-rays after three iterations. Different common diffraction standards CeO{sub 2}, Au, and Si show an energy deviation of 14 eV. As an application, the proposed method has been applied to determine the energy-sensitive first sharp diffraction peak of network forming GeO{sub 2} glass at high pressure, exhibiting a distinct behavior in the pressure range of 2-4 GPa. Another application presented is pair distribution function measurement using calibrated high-energy x-rays at 82.273 keV. Unlike the traditional x-ray absorption-based calibration method, the proposed approach does not rely on any edges of specific elements, and is applicable to the hard x-ray region where no appropriate absorption edge is available.

Hong Xinguo; Chen Zhiqiang [Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794 (United States); Duffy, Thomas S. [Department of Geosciences, Princeton University, Princeton, New Jersey 08544 (United States)

2012-06-15T23:59:59.000Z

355

X-Ray Diffraction on NIF  

SciTech Connect

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

356

COMPARISON OF MILLIMETER-WAVE AND X-RAY EMISSION IN SEYFERT GALAXIES  

SciTech Connect

We compare the emission at multiple wavelengths of an extended Seyfert galaxy sample, including both types of Seyfert nuclei. We use the Caltech Submillimeter Observatory to observe the CO J = 2-1 transition line in a sample of 45 Seyfert galaxies and detect 35 of them. The galaxies are selected by their joint soft X-ray (0.1-2.4 keV) and far-infrared ({lambda} = 60-100 {mu}m) emission from the ROSAT/IRAS sample. Since the CO line widths (W{sub CO}) reflect the orbital motion in the gravitational potential of the host galaxy, we study how the kinematics are affected by the central massive black hole (BH), using the X-ray luminosity. A significant correlation is found between the CO line width and hard (0.3-8 keV from Chandra and XMM-Newton) X-ray luminosity for both types of Seyfert nuclei. Assuming an Eddington accretion to estimate the BH mass (M{sub BH}) from the X-ray luminosity, the W{sub CO}-L{sub X} relation establishes a direct connection between the kinematics of the molecular gas of the host galaxy and the nuclear activity, and corroborates the previous studies that show that the CO is a good surrogate for the bulge mass. We also find a tight correlation between the (soft and hard) X-ray and the CO luminosities for both Seyfert types. These results indicate a direct relation between the molecular gas (i.e., star formation activity) of the host galaxy and the nuclear activity. To establish a clear causal connection between molecular gas and the fueling of nuclear activity, high-resolution maps (<100 pc) of the CO emission of our sample will be required and provided in a forthcoming Atacama Large Millimeter Array observation.

Monje, R. R.; Blain, A. W.; Phillips, T. G. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125-4700 (United States)

2011-08-01T23:59:59.000Z

357

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

358

Absorbed XFEL Dose in the Components of the LCLS X-Ray Optics  

Science Conference Proceedings (OSTI)

There is great concern that the short, intense XFEL pulse of the LCLS will damage the optics that will be placed into the beam. We have analyzed the extent of the problem by considering the anticipated materials and position of the optical components in the beam path, calculated the absorbed dose as a function of photon energy, and compared these doses with the expected doses required (i) to observe rapid degradation due to thermal fatigue, (ii) to reach the melting temperature, or (iii) to actually melt the material. We list the materials that are anticipated to be placed into the Linac Coherent Light Source (LCLS) x-ray free electron laser (XFEL) beam line, their positions, and the absorbed dose, and compare this dose with anticipated damage thresholds.

Hau-Riege, Stefan

2010-12-03T23:59:59.000Z

359

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

Science Conference Proceedings (OSTI)

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

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

2012-12-15T23:59:59.000Z

360

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 pattern in the surface of a silicon wafer by exposing and developing the resist and then etching the silicon substrate. Importantly, the photoresist is variably exposed so that when developed some of the resist layer remains. The remaining undeveloped resist acts as an etchant barrier to the reactive plasma used to etch the silicon substrate and therefore provides the ability etch structures of variable depths.

Morales, Alfredo M. (Livermore, CA); Gonzales, Marcela (Seattle, WA)

2006-03-07T23:59:59.000Z

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.


361

ASCA Observation of an X-Ray-Luminous Active Nucleus in Markarian 231  

E-Print Network (OSTI)

We have obtained a moderately long (100 kilosecond) ASCA observation of the Seyfert 1 galaxy Markarian 231, the most luminous of the local ultraluminous infrared galaxy (ULIRG) population. In the best-fitting model we do not see the X-ray source directly; the spectrum consists of a scattered power-law component and a reflection component, both of which have been absorbed by a column N_H \\approx 3 X 10^(22)/cm^2. About 3/4 of the observed hard X-rays arise from the scattered component, reducing the equivalent width of the iron K alpha line. The implied ratio of 1-10 keV X-ray luminosity to bolometric luminosity, L_x/L_bol \\sim 2%, is typical of Sy 1 galaxies and radio-quiet QSOs of comparable bolometric luminosities, and indicates that the bolometric luminosity is dominated by the AGN. Our estimate of the X-ray luminosity also moves Mrk 231 in line with the correlations found for AGN with extremely strong Fe II emission. A second source separated by about 2 arcminutes is also clearly detected, and contributes ...

Maloney, P R; Maloney, Philip R.; Reynolds, Christopher S

2000-01-01T23:59:59.000Z

362

Survey on solar X-ray flares and associated coherent radio emissions  

E-Print Network (OSTI)

The radio emission during 201 X-ray selected solar flares was surveyed from 100 MHz to 4 GHz with the Phoenix-2 spectrometer of ETH Zurich. The selection includes all RHESSI flares larger than C5.0 jointly observed from launch until June 30, 2003. Detailed association rates of radio emission during X-ray flares are reported. In the decimeter wavelength range, type III bursts and the genuinely decimetric emissions (pulsations, continua, and narrowband spikes) were found equally frequently. Both occur predominantly in the peak phase of hard X-ray (HXR) emission, but are less in tune with HXRs than the high-frequency continuum exceeding 4 GHz, attributed to gyrosynchrotron radiation. In 10% of the HXR flares, an intense radiation of the above genuine decimetric types followed in the decay phase or later. Classic meter-wave type III bursts are associated in 33% of all HXR flares, but only in 4% they are the exclusive radio emission. Noise storms were the only radio emission in 5% of the HXR flares, some of them with extended duration. Despite the spatial association (same active region), the noise storm variations are found to be only loosely correlated in time with the X-ray flux. In a surprising 17% of the HXR flares, no coherent radio emission was found in the extremely broad band surveyed. The association but loose correlation between HXR and coherent radio emission is interpreted by multiple reconnection sites connected by common field lines.

Arnold O. Benz; Paolo Grigis; Andre Csillagy; Pascal Saint-Hilaire

2004-10-19T23:59:59.000Z

363

Workshops on Science Enabled by a Coherent, CW, Synchrotron X-ray Source, June 2011  

Science Conference Proceedings (OSTI)

In June of 2011 we held six two-day workshops called "XDL-2011: Science at the Hard X-ray Diffraction Limit". The six workshops covered (1) Diffraction-based imaging techniques, (2) Biomolecular structure from non-crystalline materials, (3) Ultra-fast science, (4) High-pressure science, (5) Materials research with nano-beams and (6) X-ray photon correlation spectroscopy (XPCS), In each workshop, invited speaker from around the world presented examples of novel experiments that require a CW, diffraction-limited source. During the workshop, each invited speaker provided a one-page description of the experiment and an illustrative graphic. The experiments identified by the workshops demonstrate the broad and deep scientific case for a CW coherent synchrotron x-ray source. The next step is to perform detailed simulations of the best of these ideas to test them quantitatively and to guide detailed x-ray beam-line designs. These designs are the first step toward developing detailed facility designs and cost estimates.

Brock, Joel

2012-01-03T23:59:59.000Z

364

An X-ray Reprocessing Model of Disk Thermal Emission in Type 1 Seyfert Galaxies  

E-Print Network (OSTI)

Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, & Ryde for the X-ray binary Cygnus X-1 and later applied to Seyfert galaxies by Zdziarski, Lubi\\'nski, & Smith, feedback between the radiation reprocessed by the disk and the thermal Comptonization emission from the hot central plasma plays a pivotal role in determining the X-ray spectrum, and as we show, the optical and ultraviolet spectra as well. Seemingly uncorrelated optical/UV and X-ray light curves, similar to those which have been observed from these objects can be explained by variations in the size, shape, and temperature of the Comptonizing plasma. Furthermore, by positing a disk mass accretion rate which satisfies a condition for global energy balance between the thermal Comptonization luminosity and the power available fr...

Chiang, J

2002-01-01T23:59:59.000Z

365

Discovery of Two Types of X-ray Dips in Cyg X-1  

E-Print Network (OSTI)

We observed Cyg X-1 with {\\em RXTE} contiguously over its 5.6-day binary orbit. The source was found to be in the hard state throughout the observation. Many intensity dips were detected in the X-ray light curves. We found that the dips fell into two distinct categories based on their spectral properties. One type exhibits strong energy-dependent attenuation of X-ray emission at low energies during a dip, which is characteristic of photoelectric absorption, but the other type shows nearly energy-independent attenuation. While the first type of dips are likely caused by density enhancement in an inhomogeneous wind of the companion star, as previous studies have indicated, the second type might be due to partial obscuration of an extended X-ray emitting region by optically thick ``clumps'' in the accretion flow. It is also possible that the latter are caused by a momentary decrease in the X-ray luminosity of the source, due, for instance, to a decrease in the mass accretion rate, or by Thomson scattering in highly ionized ``clumps''. We discuss the implications of these scenarios.

Y. X. Feng; Wei Cui

2001-12-06T23:59:59.000Z

366

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (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.

367

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

368

X-Ray Diffraction Microscopy of Magnetic Structures  

NLE Websites -- All DOE Office Websites (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.

369

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

370

Photon Sciences | Beamlines | IXS: Inelastic X-ray Scattering  

NLE Websites -- All DOE Office Websites (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

371

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

372

X-Ray Diffraction Microscopy of Magnetic Structures  

NLE Websites -- All DOE Office Websites (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.

373

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (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.

374

APS 7-BM Beamline: X-Ray Resources  

NLE Websites -- All DOE Office Websites (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.

375

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (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.

376

X-Ray Diffraction Microscopy of Magnetic Structures  

NLE Websites -- All DOE Office Websites (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.

377

Fabrication process for a gradient index x-ray lens  

DOE Patents (OSTI)

A process for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments m the soft x-ray region.

Bionta, Richard M. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA); Skulina, Kenneth M. (Livermore, CA)

1995-01-01T23:59:59.000Z

378

Fabrication process for a gradient index x-ray lens  

DOE Patents (OSTI)

A process is disclosed for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments in the soft x-ray region. 13 figures.

Bionta, R.M.; Makowiecki, D.M.; Skulina, K.M.

1995-01-17T23:59:59.000Z

379

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,

380

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (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.

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

Part 2: Coherent emission from Free Electron Lasers  

NLE Websites -- All DOE Office Websites (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),

382

Ultra-short wavelength x-ray system  

DOE Patents (OSTI)

A method and apparatus to generate a beam of coherent light including x-rays or XUV by colliding a high-intensity laser pulse with an electron beam that is accelerated by a synchronized laser pulse. Applications include x-ray and EUV lithography, protein structural analysis, plasma diagnostics, x-ray diffraction, crack analysis, non-destructive testing, surface science and ultrafast science.

Umstadter, Donald (Ann Arbor, MI); He, Fei (Ann Arbor, MI); Lau, Yue-Ying (Potomac, MD)

2008-01-22T23:59:59.000Z

383

Measurements of the LCLS Laser Heater and its impact on the x-ray FEL Performance  

Science Conference Proceedings (OSTI)

The very bright electron beam required for an x-ray free-electron laser (FEL), such as the Linac Coherent Light Source (LCLS), is susceptible to a microbunching instability in the magnetic bunch compressors, prior to the FEL undulator. The uncorrelated electron energy spread in the LCLS can be increased by an order of magnitude to provide strong Landau damping against the instability without degrading the FEL performance. To this end, a 'laser-heater' system has been installed in the LCLS injector, which modulates the energy of a 135-MeV electron bunch with an IR laser beam in a short undulator, enclosed within a four-dipole chicane. In this paper, we report detailed measurements of laser heater-induced energy spread, including the unexpected self-heating phenomenon when the laser energy is very low. We discuss the suppression of the microbunching instability with the laser heater and its impact on the x-ray FEL performance. We also present the analysis of these experimental results and develop a three-dimensional longitudinal space charge model to explain the self-heating effect.

Huang, Zhirong; Brachmann, A.; Decker, F.-J.; Ding, Y.; Dowell, D.; Emma, P.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, Ph.; Iverson, R.; Loos, H.; Miahnahri, A.; Nuhn, H.-D.; Ratner, D.; Stupakov, G.; Turner, J.; Welch, J.; White, W.; Wu, J.; Xiang, D.

2009-12-17T23:59:59.000Z

384

Optical and x-ray imaging of electron beams using synchrotron emission  

SciTech Connect

In the case of very low eniittance electron and positron storage ring beams, it is impossible to make intrusive measurements of beam properties without increasing the emittance and possibly disrupting the beam. In cases where electron or positron beams have high average power densities (such as free electron laser linacs), intrusive probes such as wires and optical transition radiation screens or Cherenkov emitting screens can be easily damaged or destroyed. The optical and x-ray emissions from the bends in the storage rings and often from linac bending magnets can be used to image the beam profile to obtain emittance information about the beam. The techniques, advantages and limitations of using both optical and x-ray synchrotron emission to measure beam properties are discussed and the possibility of single bunch imaging is considered. The properties of suitable imagers and converters such as phosphors are described. Examples of previous, existing and planned applications are given where available, including a pinhole imaging system currently being designed for the Advanced Photon Source at Argonne National Laboratory.

Wilke, M.D.

1994-12-01T23:59:59.000Z

385

NIST X-Ray Mass Attenuation Coefficients - Version History  

Science Conference Proceedings (OSTI)

... year, month day with database access date.) Hubbell, JH and Seltzer, SM (2004), Tables of X-Ray Mass Attenuation Coefficients and Mass Energy- ...

2010-10-05T23:59:59.000Z

386

4D Functional Materials Science with X-ray Microscopy  

Science Conference Proceedings (OSTI)

Ultrafast Electron Diffraction Studies of Lattice Dynamics in Thin Bismuth Films Understanding Fatigue and Corrosion-Fatigue Behavior by In Situ 3D X-ray...

387

Optical and X-ray Imaging Techniques for Material Characterization ...  

Science Conference Proceedings (OSTI)

Ultrafast X-ray and 2-dimensional UV Spectroscopy of TiO2 Nanoparticles: Majed Chergui1; 1Ecole Polytechnique Fdrale de Lausanne Mesoporous titanium...

388

X-Ray and Neutron Diffraction - Programmaster.org  

Science Conference Proceedings (OSTI)

Oct 20, 2010 ... Strain Determination in Nanoscale Microelectronic Materials Using X-Ray Diffraction: Conal Murray1; 1IBM T.J. Watson Research Center

389

High Temperature X-ray Diffraction Characterization of Thermal ...  

Science Conference Proceedings (OSTI)

Application of Conical Beam X-Ray Tomography to Multi-Phase Materials ... Digital Construction and Characterization of Reticulated Porous Microstructures...

390

dosimetry of x-rays, gamma rays and electrons  

Science Conference Proceedings (OSTI)

... NIST and BIPM Standards for Air Kerma in Medium-Energy X-rays ... of the codes are available from the Government Printing Office, Washington, DC ...

2013-06-28T23:59:59.000Z

391

APS X-ray Optics Fabrication and Characterization Facility  

SciTech Connect

The APS is in the process of assembling an X-ray Optics Fabrication and characterization Facility. This report will describe its current (as of February 1993) design.

Davey, S.

1993-02-01T23:59:59.000Z

392

X-ray compass for determining device orientation  

DOE Patents (OSTI)

An apparatus and method for determining the orientation of a device with respect to an x-ray source are disclosed. In one embodiment, the present invention is coupled to a medical device in order to determine the rotational orientation of the medical device with respect to the x-ray source. In such an embodiment, the present invention is comprised of a scintillator portion which is adapted to emit photons upon the absorption of x-rays emitted from the x-ray source. An x-ray blocking portion is coupled to the scintillator portion. The x-ray blocking portion is disposed so as to vary the quantity of x-rays which penetrate the scintillator portion based upon the particular rotational orientation of the medical device with respect to the x-ray source. A photon transport mechanism is also coupled to the scintillator portion. The photon transport mechanism is adapted to pass the photons emitted from the scintillator portion to an electronics portion. By analyzing the quantity of the photons, the electronics portion determines the rotational orientation of the medical device with respect to the x-ray source. 25 figs.

Da Silva, L.B.; Matthews, D.L.; Fitch, J.P.; Everett, M.J.; Colston, B.W.; Stone, G.F.

1999-06-15T23:59:59.000Z

393

Synchrotron X-ray Studies of Supercritical Carbon Dioxide/ Reservoir...  

Open Energy Info (EERE)

Edit with form History Facebook icon Twitter icon Synchrotron X-ray Studies of Supercritical Carbon Dioxide Reservoir Rock Interfaces Geothermal Lab Call Project Jump to:...

394

Phase Sensitive X-ray Imager for More Accurate Digital ...  

Livermore Lab Report. News Archive. News ... use of higher energy X-rays which would result in a lower amount of absorbed radiation to the ... testing ...

395

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

Proceedings of the 12th International Clay Conference, Bahia Blanca, Argentina, July 22-28, 2001. Gibbs, D. X-ray magnetic scattering. Synchrotron Radiation News...

396

Neutron and X-Ray Studies of Advanced Materials IV  

Science Conference Proceedings (OSTI)

We propose to organize a seven-session Symposium on Neutron and X-Ray ... the advent of new powerful neutron sources such as the Spallation Neutron...

397

Available Technologies: High Temperature Strain Cell for X-ray ...  

High Temperature Strain Cell for X-ray ... Six hexapole infrared lamps focus inside the sample chamber onto a ceramic material sample with a spherical ...

398

X-ray compass for determining device orientation  

DOE Patents (OSTI)

An apparatus and method for determining the orientation of a device with respect to an x-ray source. In one embodiment, the present invention is coupled to a medical device in order to determine the rotational orientation of the medical device with respect to the x-ray source. In such an embodiment, the present invention is comprised of a scintillator portion which is adapted to emit photons upon the absorption of x-rays emitted from the x-ray source. An x-ray blocking portion is coupled to the scintillator portion. The x-ray blocking portion is disposed so as to vary the quantity of x-rays which penetrate the scintillator portion based upon the particular rotational orientation of the medical device with respect to the x-ray source. A photon transport mechanism is also coupled to the scintillator portion. The photon transport mechanism is adapted to pass the photons emitted from the scintillator portion to an electronics portion. By analyzing the quantity of the photons, the electronics portion determines the rotational orientation of the medical device with respect to the x-ray source.

Da Silva, Luiz B. (Danville, CA); Matthews, Dennis L. (Moss Beach, CA); Fitch, Joseph P. (Livermore, CA); Everett, Matthew J. (Pleasanton, CA); Colston, Billy W. (Livermore, CA); Stone, Gary F. (Livermore, CA)

1999-01-01T23:59:59.000Z

399

Inelastic X-ray Scattering Reveals Microscopic Transport Properties...  

NLE Websites -- All DOE Office Websites (Extended Search)

Inelastic X-ray Scattering Reveals Microscopic Transport Properties of Molten Aluminum Oxide The transport properties of high-temperature oxide melts are of considerable interest...

400

SLAC National Accelerator Laboratory - X-ray Laser Pulses in...  

NLE Websites -- All DOE Office Websites (Extended Search)

SLAC researchers have demonstrated for the first time how to produce pairs of X-ray laser pulses in slightly different wavelengths, or colors, with finely adjustable intervals...

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

NIST X-Ray Transition Energies Version History  

Science Conference Proceedings (OSTI)

... Jr., P. Indelicato, L. de Billy, E. Lindroth, and J. Anton, "X-ray transition energies: new approach to a ... [Type of medium] Available: URL [Access date]. ...

2010-10-05T23:59:59.000Z

402

Optical and X-ray Imaging Techniques for Material Characterization  

Science Conference Proceedings (OSTI)

Hyperspectral CARS Microscopy in the Fingerprint Region In Situ X-ray ... Opportunities for Multimodal CARS Microscopy in Materials Science Photoemission...

403

X RAY TU E WITH MAGNETI ELE TRON STEERING  

Sandia National Laboratories has created an improved efficiency compact X-ray source to address a wide range ... escape the anode and cause electron h ...

404

Temporal multiplexing radiography for dynamic x-ray imaging  

Science Conference Proceedings (OSTI)

All current x-ray imaging devices acquire images sequentially, one at a time. Using a spatially distributed multibeam x-ray source we recently demonstrated the feasibility for multiplexing x-ray imaging, which can significantly increase the data collection speed. Here we present a general methodology for dynamic x-ray imaging of an object in cyclic motion with temporal multiplexing. Compared to the conventional sequential imaging technique, where 2N-1 phase images are required and N exposures are needed for a single phase image, a temporal multiplexing of dimension 2N-1 can reduce the imaging time by a factor of N while maintaining the temporal resolution.

Cao Guohua [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Zhang Jian [Department of Radiation Oncology and Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Zhou, Otto; Lu Jianping [Department of Physics and Astronomy and Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina, 27599 (United States)

2009-09-15T23:59:59.000Z

405

SLAC National Accelerator Laboratory - X-ray Science  

NLE Websites -- All DOE Office Websites (Extended Search)

energy technologies. SLAC's unique X-ray facilities - the Linac Coherent Light Source (LCLS) and the Stanford Synchrotron Radiation Lightsource (SSRL) - attract thousands of...

406

New Directions in X-ray Scattering - SSRL  

NLE Websites -- All DOE Office Websites (Extended Search)

associated with chemically and radioactively contaminated ground-water. Ability to probe weak scattering from single crystals as function of energy (resonance) and x-ray...

407

Bibliography of NRL Works on X-Ray Fluorescence Authored ...  

Science Conference Proceedings (OSTI)

... LS Birks, and EJ Brooks, "Grain-Boundary Diffusion of Zinc in Copper ... 111 J. Gilfrich, "X-Ray Diffraction Studies on the Titanium-Nickel System," in ...

2012-10-05T23:59:59.000Z

408

In situ X-ray Characterization of Energy Storage Materials |...  

NLE Websites -- All DOE Office Websites (Extended Search)

to accurately characterize the dynamic electrochemical processes at the nanometer and atomic level, we have employed a set of complementary, in situ X-ray characterization...

409

For Prospective Users: Learn about x-ray research  

NLE Websites -- All DOE Office Websites (Extended Search)

research in the fields of materials science; biological science; physics; chemistry; environmental, geophysical, and planetary science; and innovative x-ray instrumentation....

410

Staff at sector 30, inelastic x-ray scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Status and Schedule Safety and Training Divisions APS Engineering Support Division AES Groups Accelerator Systems Division ASD Groups X-ray Science Division XSD Groups...

411

Improved Treatment of X-ray Resistant & Inoperable Cancers ...  

If the electron beam can be transported to the internal cancer without exposure to tissue, ... This figure shows a comparison of X-ray radiation ...

412

Spatially-Resolved X-Ray Microdiffraction Studies Inside Individual ...  

Science Conference Proceedings (OSTI)

This talk will describe recent advances including increased scanning speed, and will describe the use of this x-ray microscope to study mesoscale structural...

413

Development of Coherent X-Ray Diffraction Microscopy and Its ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2010 TMS Annual Meeting & Exhibition. Symposium , Neutron and X-Ray Studies of Advanced Materials III. Presentation Title, 2010...

414

Background X-ray Spectrum of Radioactive Samples  

Science Conference Proceedings (OSTI)

An energy-dispersive X-ray spectrometer (EDS) is commonly used with a scanning electron microscope (SEM) to analyze the elemental compositions and microstructures of a variety of samples. For example, the microstructures of nuclear fuels are commonly investigated with this technique. However, the radioactivity of some materials introduces additional X-rays that contribute to the EDS background spectrum. These X-rays are generally not accounted for in spectral analysis software, and can cause misleading results. X-rays from internal conversion [1], Bremsstrahlung [2] radiation associated with alpha ionizations and beta particle interactions [3], and gamma rays from radioactive decay can all elevate the background of radioactive materials.

Shannon Yee; Dawn E. Janney

2008-02-01T23:59:59.000Z

415

Grain Boundary Deformation Analyzed Via X-Ray Diffraction ...  

Science Conference Proceedings (OSTI)

Modeling the Influence of the Second Phase Particle Spatial Distribution on Recrystallization of AA 7050 Near-Field High Energy X-ray Diffraction Microscopy...

416

Applications of High Resolution X-ray Computed Tomography in ...  

Science Conference Proceedings (OSTI)

... data, including concentration profiles from x-ray absorption measurements during ... Dynamic Evolution of Liquid-liquid Phase Separation While Cooling in a

417

Determining the Uncertainty of X-Ray Absorption ...  

Science Conference Proceedings (OSTI)

... The apparatus uses a tungsten filament and a tungsten target to generate x rays and the detector contains a CZT crystal. ...

2005-01-28T23:59:59.000Z

418

X-ray Detection with Large Area Avalanche Photodiodes for ...  

Science Conference Proceedings (OSTI)

... The primary photon detector was a 12-element ... The overall energy range for the experiment was ... to directly detect X-rays with energies between 0.3 ...

2013-07-23T23:59:59.000Z

419

Spectrometry of X-Ray Beams Used for Calibrations  

Science Conference Proceedings (OSTI)

... and used to calibrate a wavelength-dispersive crystal x-ray spectrograph used by Lawrence Livermore National Laboratory (LLNL) to diagnose ...

2012-06-26T23:59:59.000Z

420

X-ray Tube with Magnetic Electron Steering - Energy ...  

The high average power large area X-ray tube provides ... Solar Photovoltaic; Solar ... Description This invention consists of a cathode and anode ...

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

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

422

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

423

X-ray Methods in High-Intensity Discharges and Metal-Halide Lamps: X-ray Induced Fluorescence  

SciTech Connect

We describe the use of x-ray induced fluorescence to study metal-halide high-intensity discharge lamps and to measure equilibrium vapor pressures of metal-halide salts. The physical principles of metal-halide lamps, relevant aspects of x-ray-atom interactions, the experimental method using synchrotron radiation, and x-ray induced fluorescence measurements relevant to metal-halide lamps are covered.

Curry, John J.; Lapatovich, Walter P.; Henins, Albert (NIST)

2011-12-09T23:59:59.000Z

424

Reversible Electron Beam Heating for Suppression of Microbunching Instabilities at Free-Electron Lasers  

SciTech Connect

The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) upstream and downstream of a magnetic bunch compressor chicane. The additional energy spread is introduced in the first TDS, which suppresses the microbunching instability, and then is eliminated in the second TDS. We show the feasibility of the microbunching gain suppression based on calculations and simulations including the effects of coherent synchrotron radiation. Acceptable electron beam and radio-frequency jitter are identified, and inherent options for diagnostics and on-line monitoring of the electron beam's longitudinal phase space are discussed.

Behrens, Christopher; /DESY; Huang, Zhirong; Xiang, Dao; /SLAC

2012-05-30T23:59:59.000Z

425

The Supergiant Fast X-ray Transient with the shortest orbital period: Suzaku observes one orbit in IGRJ16479-4514  

E-Print Network (OSTI)

The eclipsing hard X-ray source IGR J16479-4514 is the Supergiant Fast X-ray Transient (SFXT) with the shortest orbital period (3.32 days). This allowed us to perform a 250 ks long X-ray observation with Suzaku in 2012 February, covering most of its orbit, including the eclipse egress. Outside the eclipse, the source luminosity is around a few 1E34erg/s. The X-ray spectrum can be fit with an absorbed power law together with a neutral iron emission line at 6.4 keV. The column density is constant at 1E23 cm-2 outside the X-ray eclipse. During the eclipse it is lower, consistent with a scattering origin for the low X-ray emission during the eclipse by the supergiant companion wind. The scattered X-ray emission during the X-ray eclipse is used to directly probe the density of the companion wind at the orbital separation, resulting in 7E-14 g/cm3, which translates into a ratio Mdot_w/v_terminal = 7E-17 solar masses/km of the wind mass loss rate to the wind terminal velocity. This ratio, assuming reasonable termina...

Sidoli, L; Sguera, V; Bodaghee, A; Tomsick, J A; Pottschmidt, K; Rodriguez, J; Romano, P; Wilms, J

2013-01-01T23:59:59.000Z

426

High-brightness beamline for X-ray spectroscopy at the Advanced Light Source  

SciTech Connect

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goals of high energy resolution, high flux, and high brightness at the sample. When completed later this year, it will be the first ALS monochromatic hard-x-ray beamline, and its brightness will be an order-of-magnitude higher than presently available in this energy range. In addition, it will provide flux and resolution comparable to any other beamline now in operation. To achieve these goals, two technical improvements, relative to existing x-ray beamlines, were incorporated. First, a somewhat novel optical design for x-rays, in which matched toroidal mirrors are positioned before and after the double-crystal monochromator, was adopted. This configuration allows for high resolution by passing a collimated beam through the monochromator, and for high brightness by focusing the ALS source on the sample with unit magnification. Second, a new ''Cowan type'' double-crystal monochromator based on the design used at NSLS beamline X-24A was developed. The measured mechanical precision of this new monochromator shows significant improvement over existing designs, without using positional feedback available with piezoelectric devices. Such precision is essential because of the high brightness of the radiation and the long distance (12m) from the source (sample) to the collimating (focusing) mirror. This combination of features will provide a bright, high resolution, and stable x-ray beam for use in the x-ray spectroscopy program at the ALS.

Perera, R.C.C.; Jones, G. [Lawrence Berkeley Lab., CA (US); Lindle, D.W. [Univ. of Nevada, Las Vegas, NV (US). Dept. of Chemistry

1994-08-01T23:59:59.000Z

427

Optical and X-ray Variability in The Least Luminous AGN, NGC4395  

E-Print Network (OSTI)

We report the detection of optical and X-ray variability in the least luminous known Seyfert galaxy, NGC4395. The featureless continuum changed by a factor of 2 in 6 months, which is typical of more luminous AGN. The largest variation was seen at shorter wavelengths, so that the spectrum becomes `harder' during higher activity states. In a one week optical broad band monitoring program, a 20% change was seen between successive nights. In a 1 month period the spectral shape changed from a power law with spectral index alpha ~0 (characteristic of quasars) to a spectral index alpha ~2 (as observed in other dwarf AGN). ROSAT HRI and PSPC archive data show a variable X-ray source coincident with the galactic nucleus. A change in X-ray flux by a factor \\~2 in 15 days has been observed. When compared with more luminous AGN, NGC4395 appears to be very X-ray quiet. The hardness ratio obtained from the PSPC data suggests that the spectrum could be absorbed. We also report the discovery of weak CaIIK absorption, suggesting the presence of a young stellar cluster providing of the order of 10% of the blue light. Using HST UV archive data, together with the optical and X-ray observations, we examine the spectral energy distribution for NGC4395 and discuss the physical conditions implied by the nuclear activity under the standard AGN model. The observations can be explained by either an accreting massive black hole emitting at about 10^(-3) L_(Edd) or by a single old compact SNR with an age of 50 to 500 yr generated by a small nuclear starburst.

P. Lira; A. Lawrence; P. O'Brien; R. A. Johnson; R. Terlevich; N. Bannister

1999-01-25T23:59:59.000Z

428

At-wavelength characterization of refractive x-ray lenses using a two-dimensional grating interferometer  

SciTech Connect

We report on the application of a two-dimensional hard x-ray grating interferometer to x-ray optics metrology. The interferometer is sensitive to refraction angles in two perpendicular directions with a precision of 10 nrad. It is used to observe the wavefront changes induced by a single parabolic beryllium focusing lens of large radius of curvature. The lens shape is reconstructed and its residual aberrations are analyzed. Its profile differs from an ideal parabolic shape by less than 2 {mu}m or {lambda}/50 at {lambda} = 0.54 A wavelength.

Rutishauser, Simon; David, Christian [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Zanette, Irene [European Synchrotron Radiation Facility, 38043 Grenoble (France); Weitkamp, Timm [Synchrotron Soleil, 91192 Gif-sur-Yvette (France); Donath, Tilman [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Dectris Ltd., 5400 Baden (Switzerland)

2011-11-28T23:59:59.000Z

429

Optics Design for a Soft X-ray FEL at the SLAC A-Line  

SciTech Connect

LCLS capabilities can be significantly extended with a second undulator aiming at the soft x-ray spectrum (1-5 nm). To allow for simultaneous hard and soft x-ray operations, 14 GeV beams at the end of the LCLS accelerator can be intermittently switched into the SLAC A-line (the beam transport line to End Station A) where the second undulator may be located. In this paper, we discuss the A-line optics design for transporting the high-brightness LCLS beams using the existing tunnel. To preserve the high brightness of the LCLS beams, special attention is paid to effects of incoherent and coherent synchrotron radiation. Start-to-end simulations using realistic LCLS beam distributions are carried out.

Geng, H; Ding, Y.; Emma, P.; Huang, Z.; Nosochkov, Y.; Woodley, M.; /SLAC

2009-05-15T23:59:59.000Z

430

X-ray attenuation properties of stainless steel (u)  

SciTech Connect

Stainless steel vessels are used to enclose solid materials for studying x-ray radiolysis that involves gas release from the materials. Commercially available stainless steel components are easily adapted to form a static or a dynamic condition to monitor the gas evolved from the solid materials during and after the x-ray irradiation. Experimental data published on the x-ray attenuation properties of stainless steel, however, are very scarce, especially over a wide range of x-ray energies. The objective of this work was to obtain experimental data that will be used to determine how a poly-energetic x-ray beam is attenuated by the stainless steel container wall. The data will also be used in conjunction with MCNP (Monte Carlos Nuclear Particle) modeling to develop an accurate method for determining energy absorbed in known solid samples contained in stainless steel vessels. In this study, experiments to measure the attenuation properties of stainless steel were performed for a range of bremsstrahlung x-ray beams with a maximum energy ranging from 150 keV to 10 MeV. Bremsstrahlung x-ray beams of these energies are commonly used in radiography of engineering and weapon components. The weapon surveillance community has a great interest in understanding how the x-rays in radiography affect short-term and long-term properties of weapon materials.

Wang, Lily L [Los Alamos National Laboratory; Berry, Phillip C [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

431

High-energy x-ray production with pyroelectric crystals  

Science Conference Proceedings (OSTI)

The invention of pyroelectric x-ray generator technology has enabled researchers to develop ultraportable, low-power x-ray sources for use in imaging, materials analysis, and other applications. For many applications, the usefulness of an x-ray source is determined by its yield and endpoint energy. In x-ray fluorescence, for example, high-energy sources enable the excitation of the K-shell x-ray peaks for high-Z materials as well as the lower-energy L-shell peaks, allowing more positive sample identification. This report shows how a paired-crystal pyroelectric source can be used to approximately double the endpoint x-ray energy, in addition to doubling the x-ray yield, versus a single-crystal source. As an example of the advantage of a paired-crystal system, we present a spectrum showing the fluorescence of the K shell of thorium using a pyroelectric source, as well as a spectrum showing the fluorescence of the K shell of lead. Also shown is an x-ray spectrum with an endpoint energy of 215 keV.

Geuther, Jeffrey A.; Danon, Yaron [Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2005-05-15T23:59:59.000Z

432

ESRF HIGHLIGHTS 2005 X-RAY ABSORPTION AND MAGNETIC SCATTERING  

E-Print Network (OSTI)

96 ESRF HIGHLIGHTS 2005 X-RAY ABSORPTION AND MAGNETIC SCATTERING References [1] C. Antoniak, J to original phenomena. These effects are observed in charge-density wave (CDW) materials. Upon cooling of the screw like dislocation shown in Figure 121b. #12;97 HIGHLIGHTS 2005 ESRF X-RAY ABSORPTION AND MAGNETIC

Paris-Sud 11, Université de

433

X-ray imaging with grazing-incidence microscopes developed for the LIL program  

SciTech Connect

This article describes x-ray imaging with grazing-incidence microscopes, developed for the experimental program carried out on the Ligne d'Integration Laser (LIL) facility [J. P. Le Breton et al., Inertial Fusion Sciences and Applications 2001 (Elsevier, Paris, 2002), pp. 856-862] (24 kJ, UV--0.35 nm). The design includes a large target-to-microscope (400-700 mm) distance required by the x-ray ablation issues anticipated on the Laser MegaJoule facility [P. A. Holstein et al., Laser Part. Beams 17, 403 (1999)] (1.8 MJ) which is under construction. Two eight-image Kirkpatrick-Baez microscopes [P. Kirkpatrick and A. V. Baez J. Opt. Soc. Am. 38, 766 (1948)] with different spectral wavelength ranges and with a 400 mm source-to-mirror distance image the target on a custom-built framing camera (time resolution of {approx}80 ps). The soft x-ray version microscope is sensitive below 1 keV and its spatial resolution is better than 30 {mu}m over a 2-mm-diam region. The hard x-ray version microscope has a 10 {mu}m resolution over an 800-{mu}m-diam region and is sensitive in the 1-5 keV energy range. Two other x-ray microscopes based on an association of toroidal/spherical surfaces (T/S microscopes) produce an image on a streak camera with a spatial resolution better than 30 {mu}m over a 3 mm field of view in the direction of the camera slit. Both microscopes have been designed to have, respectively, a maximum sensitivity in the 0.1-1 and 1-5 keV energy range. We present the original design of these four microscopes and their test on a dc x-ray tube in the laboratory. The diagnostics were successfully used on LIL first experiments early in 2005. Results of soft x-ray imaging of a radiative jet during conical shaped laser interaction are shown.

Rosch, R.; Boutin, J. Y.; Le Breton, J. P.; Gontier, D.; Jadaud, J. P.; Reverdin, C.; Soullie, G.; Lidove, G.; Maroni, R. [CEA/DIF, BP 12, 91680 Bruyeres-Le-Chatel (France)

2007-03-15T23:59:59.000Z

434

Resonant Soft X-Ray Scattering - Combining Structural with Spectroscopic  

NLE Websites -- All DOE Office Websites (Extended Search)

Resonant Soft X-Ray Scattering - Combining Structural with Spectroscopic 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 absorption spectroscopy has become an important tool in understanding the electronic structure of materials. Resonant absorption edges in the soft x-ray regime are especially interesting as they allow the study of the lighter elements, such as in organic or organo-metallic substances, as well as important L-edges of the 3d transition metals important in magnetic and oxide systems. Measurements of soft x-ray absorption spectra are inherently surface sensitive, and are plagued by issues such as extinction (in electron yield measurements) or self absorption (in fluorescence yield

435

Broadband high resolution X-ray spectral analyzer  

DOE Patents (OSTI)

A broad bandwidth high resolution x-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces x-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available x-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for x-ray microanalysis or in research applications such as laboratory and astrophysical x-ray and particle spectroscopy.

Silver, Eric H. (Berkeley, CA); Legros, Mark (Berkeley, CA); Madden, Norm W. (Livermore, CA); Goulding, Fred (Lafayette, CA); Landis, Don (Pinole, CA)

1998-01-01T23:59:59.000Z

436

X-Ray Observations of Gamma-Ray Burst Afterglows  

E-Print Network (OSTI)

The discovery by the BeppoSAX satellite of X-ray afterglow emission from the gamma-ray burst which occurred on 28 February 1997 produced a revolution in our knowledge of the gamma-ray burst phenomenon. Along with the discovery of X-ray afterglows, the optical afterglows of gamma-ray bursts were discovered and the distance issue was settled, at least for long $\\gamma$-ray bursts. The 30 year mystery of the gamma-ray burst phenomenon is now on the way to solution. Here I rewiew the observational status of the X-ray afterglow emission, its mean properties (detection rate, continuum spectra, line features, and light curves), and the X-ray constraints on theoretical models of gamma-ray bursters and their progenitors. I also discuss the early onset afterglow emission, the remaining questions, and the role of future X-ray afterglow observations.

Filippo Frontera

2004-06-25T23:59:59.000Z

437

Broadband high resolution X-ray spectral analyzer  

DOE Patents (OSTI)

A broad bandwidth high resolution X-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces X-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available X-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for X-ray microanalysis or in research applications such as laboratory and astrophysical X-ray and particle spectroscopy. 6 figs.

Silver, E.H.; Legros, M.; Madden, N.W.; Goulding, F.; Landis, D.

1998-07-07T23:59:59.000Z

438

Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism  

NLE Websites -- All DOE Office Websites (Extended Search)

Unexpected Angular Dependence of Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Wednesday, 29 August 2007 00:00 Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and x-ray polarization, but their orientation relative to the crystallographic axes must be taken into account for accurate interpretation of XMLD data. Magnetism and X Rays

439

THE XMM-NEWTON X-RAY SPECTRA OF THE MOST X-RAY LUMINOUS RADIO-QUIET ROSAT BRIGHT SURVEY-QSOs: A REFERENCE SAMPLE FOR THE INTERPRETATION OF HIGH-REDSHIFT QSO SPECTRA  

SciTech Connect

We present the broadband X-ray properties of four of the most X-ray luminous (L{sub X} {>=} 10{sup 45} erg s{sup -1} in the 0.5-2 keV band) radio-quiet QSOs found in the ROSAT Bright Survey. This uniform sample class, which explores the extreme end of the QSO luminosity function, exhibits surprisingly homogenous X-ray spectral properties: a soft excess with an extremely smooth shape containing no obvious discrete features, a hard power law above 2 keV, and a weak narrow/barely resolved Fe K{alpha} fluorescence line for the three high signal-to-noise ratio (S/N) spectra. The soft excess can be well fitted with only a soft power law. No signatures of warm or cold intrinsic absorbers are found. The Fe K{alpha} centroids and the line widths indicate emission from neutral Fe (E = 6.4 keV) originating from cold material from distances of only a few light days or further out. The well-constrained equivalent widths (EW) of the neutral Fe lines are higher than expected from the X-ray Baldwin effect which has been only poorly constrained at very high luminosities. Taking into account our individual EW measurements, we show that the X-ray Baldwin effect flattens above L{sub X} {approx} 10{sup 44} erg s{sup -1} (2-10 keV band) where an almost constant (EW) of {approx}100 eV is found. We confirm the assumption of having very similar X-ray active galactic nucleus properties when interpreting stacked X-ray spectra. Our stacked spectrum serves as a superb reference for the interpretation of low S/N spectra of radio-quiet QSOs with similar luminosities at higher redshifts routinely detected by XMM-Newton and Chandra surveys.

Krumpe, M.; Markowitz, A. [University of California, San Diego, Center for Astrophysics and Space Sciences, 9500 Gilman Drive, La Jolla, CA 92093-0424 (United States); Lamer, G. [Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam (Germany); Corral, A., E-mail: mkrumpe@ucsd.ed [INAF-Osservatorio Astronomico di Brera, via Brera 28, 20121 Milan (Italy)

2010-12-20T23:59:59.000Z