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1

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

2

Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism  

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

Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print 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 The ancient Greeks and also the Chinese knew about strange and rare stones with the power to attract iron. Moreover, when freely suspended these objects pointed north-south. Throughout the past, we have used this phenomenon-magnetism-for navigation and more recently for power production and digital information storage, all while trying to explore and understand its origins. In 1986 researchers at a facility similar to the ALS observed for the first time that the absorption of x rays depends not only on the composition of a material-that is, if it contains iron, nickel, or other elements-but also on its magnetism. The effect is unique in that it allows us to distinguish which atomic species magnetism originates from and provides information about their local atomic environment-for example, whether a magnetic species is surrounded by 4 or 6 oxygen atoms. A research team at the ALS has now shown that the relationship between magnetic order and absorption of x rays is even more complex and exciting than has been assumed for the past 20 years, leading to a reassessment of previous results.

3

Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism  

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

Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print 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 The ancient Greeks and also the Chinese knew about strange and rare stones with the power to attract iron. Moreover, when freely suspended these objects pointed north-south. Throughout the past, we have used this phenomenon-magnetism-for navigation and more recently for power production and digital information storage, all while trying to explore and understand its origins. In 1986 researchers at a facility similar to the ALS observed for the first time that the absorption of x rays depends not only on the composition of a material-that is, if it contains iron, nickel, or other elements-but also on its magnetism. The effect is unique in that it allows us to distinguish which atomic species magnetism originates from and provides information about their local atomic environment-for example, whether a magnetic species is surrounded by 4 or 6 oxygen atoms. A research team at the ALS has now shown that the relationship between magnetic order and absorption of x rays is even more complex and exciting than has been assumed for the past 20 years, leading to a reassessment of previous results.

4

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

5

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.

6

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.

7

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.

8

Surface-Sensitive, Element-Specific Magnetometry with X-Ray Linear Dichroism  

SciTech Connect

Here it is shown that the magnetic linear dichroism in x-ray photoemission (XMLD) signal can be used to measure the element specific magnetic moments in ultra thin alloy films. Comparison with recent SQUID data provides a quantitative check that demonstrates that the total magnetization derived from summing the constituent elemental moments is correct.

Schumann, F.O.; Willis, R.F.; Tobin, J.G.

1999-10-06T23:59:59.000Z

9

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

10

X-ray Holograms Expose Secret Magnetism | Advanced Photon Source  

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

How Dissolved Metal Ions Interact in Solution How Dissolved Metal Ions Interact in Solution One Giant Leap for Radiation Biology? What's in the Cage Matters in Iron Antimonide Thermoelectric Materials Novel Experiments on Cement Yield Concrete Results Watching a Glycine Riboswitch "Switch" 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 X-ray Holograms Expose Secret Magnetism MAY 11, 2007 Bookmark and Share By observing changes in coherent x-ray speckle pattern, such as the one shown above, researchers are able for the first time to investigate nanoscale dynamics of antiferromagnetic domain walls, and observe a cross over from classical to quantum behavior. (Credit: O. Shpyrko)

11

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 ...

12

Magnetic soft x-ray microscopy-imaging fast spin dynamics inmagnetic nanostructures  

SciTech Connect

Magnetic soft X-ray microscopy combines 15nm spatial resolution with 70ps time resolution and elemental sensitivity. Fresnel zone plates are used as X-ray optics and X-ray magnetic circular dichroism serves as magnetic contrast mechanism. Thus scientifically interesting and technologically relevant low dimensional nanomagnetic systems can be imaged at fundamental length and ultrafast time scales in a unique way. Studies include magnetization reversal in magnetic multilayers, nanopatterned systems, vortex dynamics in nanoelements and spin current induced phenomena.

Fischer, Peter; Kim, Dong-Hyun; Mesler, Brooke L.; Chao, Weilun; Sakdinawat, Anne E.; Anderson, Erik H.

2007-06-01T23:59:59.000Z

13

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 ...

14

Imaging nanoscale magnetic structures with polarized soft x-ray photons  

SciTech Connect

Imaging nanoscale magnetic structures and their fast dynamics is scientifically interesting and technologically of highest relevance. The combination of circularly polarized soft X-ray photons which provide a strong X-ray magnetic circular dichroism effect at characteristic X-ray absorption edges, with a high resolution soft X-ray microscope utilizing Fresnel zone plate optics allows to study in a unique way the stochastical behavior in the magnetization reversal process of thin films and the ultrafast dynamics of magnetic vortices and domain walls in confined ferromagnetic structures. Future sources of fsec short and high intense soft X-ray photon pulses hold the promise of magnetic imaging down to fundamental magnetic length and time scales.

Fischer, P.; Im, M.-Y.

2010-01-18T23:59:59.000Z

15

A semiempirical linear model of indirect, flat-panel x-ray detectors  

Science Conference Proceedings (OSTI)

Purpose: It is important to understand signal and noise transfer in the indirect, flat-panel x-ray detector when developing and optimizing imaging systems. For optimization where simulating images is necessary, this study introduces a semiempirical model to simulate projection images with user-defined x-ray fluence interaction. Methods: The signal and noise transfer in the indirect, flat-panel x-ray detectors is characterized by statistics consistent with energy-integration of x-ray photons. For an incident x-ray spectrum, x-ray photons are attenuated and absorbed in the x-ray scintillator to produce light photons, which are coupled to photodiodes for signal readout. The signal mean and variance are linearly related to the energy-integrated x-ray spectrum by empirically determined factors. With the known first- and second-order statistics, images can be simulated by incorporating multipixel signal statistics and the modulation transfer function of the imaging system. To estimate the semiempirical input to this model, 500 projection images (using an indirect, flat-panel x-ray detector in the breast CT system) were acquired with 50-100 kilovolt (kV) x-ray spectra filtered with 0.1-mm tin (Sn), 0.2-mm copper (Cu), 1.5-mm aluminum (Al), or 0.05-mm silver (Ag). The signal mean and variance of each detector element and the noise power spectra (NPS) were calculated and incorporated into this model for accuracy. Additionally, the modulation transfer function of the detector system was physically measured and incorporated in the image simulation steps. For validation purposes, simulated and measured projection images of air scans were compared using 40 kV/0.1-mm Sn, 65 kV/0.2-mm Cu, 85 kV/1.5-mm Al, and 95 kV/0.05-mm Ag. Results: The linear relationship between the measured signal statistics and the energy-integrated x-ray spectrum was confirmed and incorporated into the model. The signal mean and variance factors were linearly related to kV for each filter material (r{sup 2} of signal mean to kV: 0.91, 0.93, 0.86, and 0.99 for 0.1-mm Sn, 0.2-mm Cu, 1.5-mm Al, and 0.05-mm Ag, respectively; r{sup 2} of signal variance to kV: 0.99 for all four filters). The comparison of the signal and noise (mean, variance, and NPS) between the simulated and measured air scan images suggested that this model was reasonable in predicting accurate signal statistics of air scan images using absolute percent error. Overall, the model was found to be accurate in estimating signal statistics and spatial correlation between the detector elements of the images acquired with indirect, flat-panel x-ray detectors. Conclusions: The semiempirical linear model of the indirect, flat-panel x-ray detectors was described and validated with images of air scans. The model was found to be a useful tool in understanding the signal and noise transfer within indirect, flat-panel x-ray detector systems.

Huang, Shih-Ying; Yang Kai; Abbey, Craig K.; Boone, John M. [Department of Biomedical Engineering, University of California, Davis, California, One Shields Avenue, Davis, California 95616 (United States) and Department of Radiology, University of California, Davis, Medical Center, 4860 Y Street, Ambulatory Care Center Suite 0505, Sacramento, California 95817 (United States); Department of Radiology, University of California, Davis, Medical Center, 4860 Y Street, Ambulatory Care Center Suite 0505, Sacramento, California 95817 (United States); Department of Psychological and Brain Sciences, University of California, Santa Barbara, California 92106 (United States); Department of Biomedical Engineering, University of California, Davis, California, One Shields Avenue, Davis, California 95616 (United States) and Department of Radiology, University of California, Davis, Medical Center, 4860 Y Street, Ambulatory Care Center Suite 3100, Sacramento, California 95817 (United States)

2012-04-15T23:59:59.000Z

16

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....

17

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...

18

Design of a 7-MV Linear Transformer Driver (LTD) for down-hole flash x-ray radiography.  

Science Conference Proceedings (OSTI)

Pulsed power driven flash x-ray radiography is a valuable diagnostic for subcritical experiments at the Nevada Test Site. The existing dual-axis Cygnus system produces images using a 2.25 MV electron beam diode to produce intense x-rays from a small source. Future hydrodynamic experiments will likely use objects with higher areal mass, requiring increased x-ray dose and higher voltages while maintaining small source spot size. A linear transformer driver (LTD) is a compact pulsed power technology with applications ranging from pulsed power flash x-ray radiography to high current Z-pinch accelerators. This report describes the design of a 7-MV dual-axis system that occupies the same lab space as the Cygnus accelerators. The work builds on a design proposed in a previous report [1]. This new design provides increased diode voltage from a lower impedance accelerator to improve coupling to low impedance diodes such as the self magnetic pinch (SMP) diode. The design also improves the predicted reliability by operating at a lower charge voltage and removing components that have proven vulnerable to failure. Simulations of the new design and experimental results of the 1-MV prototype are presented.

Cordova, Steve Ray; Welch, Dale Robert (Voss Scientific, Albuquerque, NM); Oliver, Bryan Velten; Rose, David Vincent (Voss Scientific, Albuquerque, NM); Johnson, David Lee (L-3 Communications - Pulse Sciences, San Leandro, CA); Bruner, Nichelle Lee (Voss Scientific, Albuquerque, NM); Leckbee, Joshua J.

2008-09-01T23:59:59.000Z

19

Studying Nanoscale Magnetism and its Dynamics with Soft X-ray Microscopy  

Science Conference Proceedings (OSTI)

Magnetic soft X-ray microscopy allows for imaging magnetic structures at a spatial resolution down to 15nm and a time resolution in the sub-100ps regime. Inherent elemental specificity can be used to image the magnetic response of individual components such as layers in multilayered systems. This review highlights current achievements and discusses the future potential of magnetic soft X-ray microscopy at fsec X-ray sources where snapshot images of ultrafast spin dynamics with a spatial resolution below 10nm will become feasible.

Mccall, Monnikue M; Fischer, Peter

2008-05-01T23:59:59.000Z

20

Magnetostatic focal spot correction for x-ray tubes operating in strong magnetic fields using iterative optimization  

Science Conference Proceedings (OSTI)

Purpose: Combining x-ray fluoroscopy and MR imaging systems for guidance of interventional procedures has become more commonplace. By designing an x-ray tube that is immune to the magnetic fields outside of the MR bore, the two systems can be placed in close proximity to each other. A major obstacle to robust x-ray tube design is correcting for the effects of the magnetic fields on the x-ray tube focal spot. A potential solution is to design active shielding that locally cancels the magnetic fields near the focal spot. Methods: An iterative optimization algorithm is implemented to design resistive active shielding coils that will be placed outside the x-ray tube insert. The optimization procedure attempts to minimize the power consumption of the shielding coils while satisfying magnetic field homogeneity constraints. The algorithm is composed of a linear programming step and a nonlinear programming step that are interleaved with each other. The coil results are verified using a finite element space charge simulation of the electron beam inside the x-ray tube. To alleviate heating concerns an optimized coil solution is derived that includes a neodymium permanent magnet. Any demagnetization of the permanent magnet is calculated prior to solving for the optimized coils. The temperature dynamics of the coil solutions are calculated using a lumped parameter model, which is used to estimate operation times of the coils before temperature failure. Results: For a magnetic field strength of 88 mT, the algorithm solves for coils that consume 588 A/cm{sup 2}. This specific coil geometry can operate for 15 min continuously before reaching temperature failure. By including a neodymium magnet in the design the current density drops to 337 A/cm{sup 2}, which increases the operation time to 59 min. Space charge simulations verify that the coil designs are effective, but for oblique x-ray tube geometries there is still distortion of the focal spot shape along with deflections of approximately 3 mm in the radial and circumferential directions on the anode. Conclusions: Active shielding is an attractive solution for correcting the effects of magnetic fields on the x-ray focal spot. If extremely long fluoroscopic exposure times are required, longer operation times can be achieved by including a permanent magnet with the active shielding design.

Lillaney, Prasheel; Shin, Mihye; Conolly, Steven M.; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States) and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States) and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Bioengineering, University of California Berkeley, Berkeley, California 94720 (United States) and Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California 94720 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States)

2012-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires  

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

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be moved at high speed by injecting nanosecond pulses of spin-polarized currents into the wires, but the motion is largely stochastic. This result will have an impact on the current development of magnetic storage devices in which data is moved electronically rather than mechanically as in computer disk drives.

22

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires  

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

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be moved at high speed by injecting nanosecond pulses of spin-polarized currents into the wires, but the motion is largely stochastic. This result will have an impact on the current development of magnetic storage devices in which data is moved electronically rather than mechanically as in computer disk drives.

23

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires  

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

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be moved at high speed by injecting nanosecond pulses of spin-polarized currents into the wires, but the motion is largely stochastic. This result will have an impact on the current development of magnetic storage devices in which data is moved electronically rather than mechanically as in computer disk drives.

24

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires  

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

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be moved at high speed by injecting nanosecond pulses of spin-polarized currents into the wires, but the motion is largely stochastic. This result will have an impact on the current development of magnetic storage devices in which data is moved electronically rather than mechanically as in computer disk drives.

25

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires  

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

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be moved at high speed by injecting nanosecond pulses of spin-polarized currents into the wires, but the motion is largely stochastic. This result will have an impact on the current development of magnetic storage devices in which data is moved electronically rather than mechanically as in computer disk drives.

26

Large Scale Soft X-ray Loops And Their Magnetic Chirality In Both Hemispheres  

E-Print Network (OSTI)

The magnetic chirality in solar atmosphere has been studied based on the soft X-ray and magnetic field observations. It is found that some of large-scale twisted soft X-ray loop systems occur for several months in the solar atmosphere, before the disappearance of the corresponding background large-scale magnetic field. It provides the observational evidence of the helicity of the large-scale magnetic field in the solar atmosphere and the reverse one relative to the helicity rule in both hemispheres with solar cycles. The transfer of the magnetic helicity from the subatmosphere is consistent with the formation of large-scale twisted soft X-ray loops in the both solar hemispheres.

Zhang, Hongqi; Gao, Yu; Su, Jiangtao; Sokoloff, D D; Kuzanyan, K

2010-01-01T23:59:59.000Z

27

An analysis of the x-ray linear dichroism spectrum for NiO thin films grown on vicinal Ag(001)  

SciTech Connect

Antiferromagnetic (AFM) NiO thin films are grown epitaxially on vicinal Ag(118) substrate and investigated by x-ray linear dichroism (XLD). We find that the NiO AFM spin exhibits an in-plane spin reorientation transition from parallel to perpendicular to the step edges with increasing the NiO film thickness. In addition to the conventional L{sub 2} adsorption edge, x-ray linear dichroism (XLD) effect at the Ni L{sub 3} adsorption edge is also measured and analyzed. The result identifies a small energy shift of the L{sub 3} peak. Temperature-dependent measurement confirms that the observed XLD effect in this system at the normal incidence of the x-rays originates entirely from the NiO magnetic ordering.

Wu, Y.Z.; Zhao, Y.; Arenholz, E.; Young, A.T.; Sinkovic, B.; Qiu, Z.Q.

2008-05-10T23:59:59.000Z

28

High Spectral Resolution X-ray Observation of Magnetic CVs: EX Hya  

SciTech Connect

In magnetic cataclysmic variables (CVs) the primary is a highly magnetized white dwarf (WD) whose field controls the accretion flow close to the WD, leading to a shock and accretion column that radiate chiefly in X-rays. We present preliminary results from a 500 ks Chandra HETG observation of the brightest magnetic CV EX Hya. From the observational dataset we are able to measure the temperature and density at different points of the cooling accretion column using sensitive line ratios. We also construct line-based light curves to search for rotational modulation of the X-ray emission.

Luna, G; Brickhouse, N S; Mauche, C W

2008-04-07T23:59:59.000Z

29

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Wednesday, 25 November 2009 00:00 Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

30

Magnetic order and interfacial coupling in oxide thin films and heterostructures probed with soft x-ray dichroism  

SciTech Connect

The combination of novel magnetic properties induced by reduced dimensionality and strong magnetic interactions across interfaces leads to intriguing new properties in magnetic hetero- and nanostructures not observed in the constituent materials in bulk form. It is the careful optimization of the characteristics of the individual layers as well as the magnetic coupling across the interface that allows us to control the magnetic properties and tailor them for devices, e.g., in information storage and processing technology. Soft x-ray magnetic spectroscopies can make unique contributions to improving our understanding of complex magnetic nanostructures since these techniques provide elemental, valence- and site-symmetry specific information with high sensitivity and tunable probing depth. X-ray magnetic circular dichroism (XMCD) is sensitive to (unidirectional) ferromagnetic order, while x-ray magnetic linear dichroism (XMLD) can also detect (uniaxial) antiferromagnetic order. A crystalline electric field with cubic symmetry induces only a weak angular dependence in XMCD spectra [1] but can cause a very pronounced anisotropy in XMLD spectra [2]. Furthermore, non-magnetic sites with a distorted local cubic symmetry can give rise to an x-ray linear dichroism (XLD). In this presentation, we discuss how to distinguish between the individual contributions to soft x-ray dichroism spectra in order to extract the wealth of information about magnetic thin films, interfaces and hetero- and nanostructures contained in the data [3, 4, 5] We determined the magnetic structure of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO)/La{sub 0.7}Sr{sub 0.3}FeO{sub 3} (LSFO) superlattices with 6 unit cell thick sublayers using soft x-ray magnetic dichroism [5]. Circular dichroism was employed to study the characteristics of the ferromagnetic LSMO layer indicating a reduced magnetic ordering temperature of 200 K compared to the bulk value of 360 K. Linear dichroism is used to analyze the antiferromagnetic order in the LSFO layers which persists up to the bulk Neel temperature near 400 K. Our experiments clearly show that when the magnetization of the LSMO layer is aligned with a magnetic field, a torque is created on the Fe moments in the LSFO layer through exchange coupling at the interface realigning the Fe moments as well. Through comparison with theoretical calculations we are able to show that independent of the LSMO magnetization direction in the sample surface plane, the Fe moments are always oriented perpendicular to the Mn moments. This perpendicular alignment is due to the frustrated exchange coupling at the interface and the weak anisotropy in the thin LSFO layer. Revisiting previous XMLD studies of the Co/NiO(001) interface taking the impact of the crystal electric field on the XMLD into account for the first time, we show that NiO(001) exhibits a crystallographic and magnetic domain structure near the surface that is identical to that of the bulk. Upon Co deposition perpendicular coupling of Co and Ni moments is observed [2, 3] that persists even in the presence of uncompensated interface moments. We also measured the asphericity and the energy splitting of the 4f states in EuO thin films [4] - a material with fascinating properties and of technological importance for spintronics applications - using XMLD. Our measurements, which are confirmed by multiplet calculations, show that there is significant 4f anisotropy. This suggests that pinning of the f states by the local environment becomes feasible and can be tuned by external conditions, chemical doping, and strain for use in device applications. Moreover, we will discuss the impact of epitaxial strain on the magnetic properties and XMLD spectra of complex oxide thin films.

Arenholz, Elke; van der Laan, G.

2009-02-01T23:59:59.000Z

31

X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires  

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

X-Ray Imaging Current-Driven X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires X-Ray Imaging Current-Driven Magnetic Domain-Wall Motion in Nanowires Print Wednesday, 26 September 2007 00:00 The quest to increase both computer data-storage density and the speed at which one can read and write the information remains unconsummated. One novel concept is based on the use of a local electric current to push magnetic domain walls along a thin nanowire. A German, Korean, Berkeley Lab team has used the x-ray microscope XM-1 at the ALS to demonstrate that magnetic domain walls in curved permalloy nanowires can be moved at high speed by injecting nanosecond pulses of spin-polarized currents into the wires, but the motion is largely stochastic. This result will have an impact on the current development of magnetic storage devices in which data is moved electronically rather than mechanically as in computer disk drives.

32

Magnet Design of a Prototype Structure for the X-ray FELs at TESLA  

E-Print Network (OSTI)

Magnet Design of a Prototype Structure for the X-ray FELs at TESLA M. Tischer, J. Pflüger Hamburger Synchrotronstrahlungslabor HASYLAB, DESY, Notkestr. 85, D-22603 Hamburg, Germany Abstract XFEL undulators for the TESLA device is suggested so that both field integrals are trimmed close to zero for all gaps. TESLA­FEL 2000

33

Standing-wave excited soft x-ray photoemission microscopy: application to Co microdot magnetic arrays  

SciTech Connect

We demonstrate the addition of depth resolution to the usual two-dimensional images in photoelectron emission microscopy (PEEM), with application to a square array of circular magnetic Co microdots. The method is based on excitation with soft x-ray standing-waves generated by Bragg reflection from a multilayer mirror substrate. Standing wave is moved vertically through sample simply by varying the photon energy around the Bragg condition. Depth-resolved PEEM images were obtained for all of the observed elements. Photoemission intensities as functions of photon energy were compared to x-ray optical calculations in order to quantitatively derive the depth-resolved film structure of the sample.

Gray, Alexander; Kronast, Florian; Papp, Christian; Yang, See-Hun; Cramm, Stefan; Krug, Ingo P.; Salmassi, Farhad; Gullikson, Eric M.; Hilken, Dawn L.; Anderson, Erik H.; Fischer, Peter; Durr, Hermann A.; Schneider, Claus M.; Fadley, Charles S.

2010-10-29T23:59:59.000Z

34

The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars  

E-Print Network (OSTI)

Two classes of X-ray pulsars, the Anomalous X-ray Pulsars and the Soft Gamma-ray Repeaters, have been recognized in the last decade as the most promising candidates for being magnetars: isolated neutron stars powered by magnetic energy. I review the observational properties of these objects, focussing on the most recent results, and their interpretation in the magnetar model. Alternative explanations, in particular those based on accretion from residual disks, are also considered. The possible relations between these sources and other classes of neutron stars and astrophysical objects are also discussed.

Mereghetti, Sandro

2008-01-01T23:59:59.000Z

35

The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars  

E-Print Network (OSTI)

Two classes of X-ray pulsars, the Anomalous X-ray Pulsars and the Soft Gamma-ray Repeaters, have been recognized in the last decade as the most promising candidates for being magnetars: isolated neutron stars powered by magnetic energy. I review the observational properties of these objects, focussing on the most recent results, and their interpretation in the magnetar model. Alternative explanations, in particular those based on accretion from residual disks, are also considered. The possible relations between these sources and other classes of neutron stars and astrophysical objects are also discussed.

Sandro Mereghetti

2008-04-01T23:59:59.000Z

36

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

37

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

38

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

39

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

40

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

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41

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in the film plane and curl around in a closed loop. At the very center of the vortex, a small, stable core exists where the magnetization points either up or down out of the plane. Three years ago, the discovery of an easy core reversal mechanism at the ALS not only made the possibility of using such systems as magnetic memories much more realistic, it also initiated investigation of the core switching mechanism itself. Now, a Belgian-German-ALS collaboration has used high-resolution, time-resolved, magnetic x-ray microscopy to experimentally reveal the first step of the reversal process: the dynamic deformation of the vortex core. The group also measured a critical vortex velocity above which reversal occurs. Both these observations provide the first experimental support for the postulated reversal mechanism.

42

Fe K-edge X-ray resonant magnetic scattering from Ba(Fe1?xCox)2As2 superconductors  

SciTech Connect

We present an X-ray resonant magnetic scattering study at the Fe-K absorption edge of the BaFe2As2 compound. The energy spectrum of the resonant scattering, together with our calculation using the full-potential linear-augmented plane wave method with a local density functional suggests that the observed resonant scattering arises from electric dipole (E1) transitions. We discuss the role of Fe K-edge X-ray resonant magnetic scattering in understanding the relationship between the structure and the antiferromagnetic transition in the doped Ba(Fe1?xCox)2As2 superconductors.

Kim, Min Gyu; Kreyssig, Andreas; Lee, Yongbin; McQueeney, Robert J.; Harmon, Bruce N.; Goldman, Alan I.

2012-06-15T23:59:59.000Z

43

Elemental and magnetic sensitive imaging using x-ray excited luminescence microscopy  

Science Conference Proceedings (OSTI)

We demonstrate the potential of x-ray excited luminescence microscopy for full-field elemental and magnetic sensitive imaging using a commercially available optical microscope, mounted on preexisting synchrotron radiation (SR) beamline end stations. The principal components of the instrument will be described. Bench top measurements indicate that a resolution of 1 {mu}m or better is possible; this value was degraded in practice due to vibrations and/or drift in the end station and associated manipulator. X-ray energy dependent measurements performed on model solar cell materials and lithographically patterned magnetic thin film structures reveal clear elemental and magnetic signatures. The merits of the apparatus will be discussed in terms of conventional SR imaging techniques.

Rosenberg, R. A.; Zohar, S.; Keavney, D. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Divan, R.; Rosenmann, D. [Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Mascarenhas, A.; Steiner, M. A. [National Renewable Energy Lab, Golden, Colorado 80401 (United States)

2012-07-15T23:59:59.000Z

44

Remediation of Cr(VI) by biogenic magnetic nanoparticles: An x-ray magnetic circular dichroism study  

SciTech Connect

Biologically synthesized magnetite (Fe{sub 3}O{sub 4}) nanoparticles are studied using x-ray absorption and x-ray magnetic circular dichroism following exposure to hexavalent Cr solution. By examining their magnetic state, Cr cations are shown to exist in trivalent form on octahedral sites within the magnetite spinel surface. The possibility of reducing toxic Cr(VI) into a stable, non-toxic form, such as a Cr{sup 3+}-spinel layer, makes biogenic magnetite nanoparticles an attractive candidate for Cr remediation.

Telling, N. D.; Coker, V. S.; Cutting, R. S.; van der Laan, G.; Pearce, C. I.; Pattrick, R. A. D.; Arenholz, E.; Lloyd, J. R.

2009-09-04T23:59:59.000Z

45

Mechanical design and analysis of an eight-pole superconducting vector magnet for soft x-ray magnetic dichroism measurements  

Science Conference Proceedings (OSTI)

An eight-pole superconducting magnet is being developed for soft x-ray magnetic dichroism (XMD) experiments at the Advanced Light Source, Lawrence Berkley National Laboratory (LBNL). Eight conical Nb{sub 3}Sn coils with Holmium poles are arranged in octahedral symmetry to form four dipole pairs that provide magnetic fields of up to 5 T in any direction relative to the incoming x-ray beam. The dimensions of the magnet yoke as well as pole taper, diameter, and length were optimized for maximum peak field in the magnet center using the software package TOSCA. The structural analysis of the magnet is performed using ANSYS with the coil properties derived using a numerical homogenization scheme. It is found that the use of orthotropic material properties for the coil has an important influence in the design of the magnet.

Arbelaez, D.; Black, A.; Prestemon, S.O.; Wang, S.; Chen, J.; Arenholz, E.

2010-01-13T23:59:59.000Z

46

X-ray absorption and magnetic circular dichroism studies of Co2FeAl in magnetic tunnel junctions  

SciTech Connect

The bulk magnetic moment and the element specific magnetic moment of Co{sub 2}FeAl thin films were examined as a function of annealing temperature by alternating gradient magnetometer (AGM) and X-ray absorption spectroscopy (XAS)/X-ray magnetic circular dichroism (XMCD), respectively. A high magnetic moment can be achieved for all annealing temperatures and the predicted bulk and interface magnetic moment of about 5 {tilde A}{sub B} are reached via heating. We will also present tunnel magnetoresistance (TMR) values of up to 153% at room temperature and 260% at 13 K for MgO based magnetic tunnel junctions (MTJs) with Co{sub 2}FeAl and Co-Fe electrodes.

Ebke, D.; Kugler, Z.; Thomas, P.; Schebaum, O.; Schafers, M.; Nissen, D.; Schmalhorst, J.; Hutten, A.; Arenholz, E.; Thomas, A.

2010-01-11T23:59:59.000Z

47

'Optical' soft x-ray arrays for fluctuation diagnostics in magnetic fusion energy experiments  

Science Conference Proceedings (OSTI)

We are developing large pixel count, fast ({>=}100 kHz) and continuously sampling soft x-ray (SXR) array for the diagnosis of magnetohydrodynamics (MHD) and turbulent fluctuations in magnetic fusion energy plasmas. The arrays are based on efficient scintillators, high thoughput multiclad fiber optics, and multichannel light amplification and integration. Compared to conventional x-ray diode arrays, such systems can provide vastly increased spatial coverage, and access to difficult locations with small neutron noise and damage. An eight-channel array has been built using columnar CsI:Tl as an SXR converter and a multianode photomultiplier tube as photoamplifier. The overall system efficiency is measured using laboratory SXR sources, while the time response and signal-to-noise performance have been evaluated by recording MHD activity from the spherical tori (ST) Current Drive Experiment-Upgrade and National Spherical Torus Experiment, both at Princeton Plasma Physics Laboratory.

Delgado-Aparicio, L.F.; Stutman, D.; Tritz, K.; Finkenthal, M.; Kaita, R.; Roquemore, L.; Johnson, D.; Majeski, R. [Johns Hopkins University, Department of Physics and Astronomy, Plasma Spectroscopy Group, Bloomberg Center 3400 N. Charles Street, Baltimore, Maryland 21218 (United States); Princeton University Plasma Physics Laboratory, P. O. Box 451, Princeton, New Jersey 08543 (United States)

2004-10-01T23:59:59.000Z

48

X-ray resonant magnetic scattering study of magnetic stripe domains in a-GdFe thin films  

SciTech Connect

X-ray resonant magnetic scattering (XRMS) has been used to investigate the structure of magnetic stripe domain patterns in thin amorphous GdFe films. Under the influence of a perpendicular magnetic field, the scattered intensity displays a smooth transition from a structure factor of correlated stripes to the form factor of isolated domains. We derive a quite general expression that relates the total scattered intensity of XRMS to the absolute value of the magnetization. Furthermore, we compare our results for the domain period with domain theory. We obtain good agreement for prealigned stripes, but disorder tends to lead to an overestimation of the period measured with XRMS.

Miguel, J.; Peters, J. F.; Toulemonde, O. M.; Goedkoop, J. B. [Van der Waals-Zeeman Institute, University of Amsterdam, Valckenierstraat 65, 1018 XE, Amsterdam (Netherlands); Dhesi, S. S.; Brookes, N. B. [European Synchrotron Radiation Facility, ESRF, Boite Postale 220, F-38043 Grenoble Cedex (France)

2006-09-01T23:59:59.000Z

49

Observation of Laser Induced Magnetization Dynamics in Co/Pd Multilayers with Coherent X-ray Scattering  

SciTech Connect

We report on time-resolved coherent x-ray scattering experiments of laser induced magnetization dynamics in Co/Pd multilayers with a high repetition rate optical pump x-ray probe setup. Starting from a multi-domain ground state, the magnetization is uniformly reduced after excitation by an intense 50 fs laser pulse. Using the normalized time correlation, we study the magnetization recovery on a picosecond timescale. The dynamic scattering intensity is separated into an elastic portion at length scales above 65 nm which retains memory of the initial domain magnetization, and a fluctuating portion at smaller length scales corresponding to domain boundary motion during recovery.

Wu, Benny

2012-04-05T23:59:59.000Z

50

Alignment and Magnet Error Tolerances for the LCLS X-Ray FEL  

E-Print Network (OSTI)

We have examined the influence of misalignments and magnet errors on the predicted performance of the Linac Coherent Light Source (LCLS). Due to the extremely large number of wiggler periods (# 10 3 ) and the small optical mode size ( 20 #m), alignment and magnet tolerances will be quite demanding. These demands may increase if the wiggler is split into separate sections by the possible inclusion of diagnostic stations, dispersive sections, etc. We have attempted to quantify such tolerances using the numerical simulation code FRED-3D. 1 INTRODUCTION The LCLS is a multi-institutional proposal for a singlepass x-ray FEL operating in the 1-2 A wavelength region, using electron beams from the SLAC linac at # 15 GeV energy [1]. The effect of field and steering errors on the performance of an X-Ray FEL operating at an optical wavelength of 4 nm based on a 7 GeV electron beam from the SLAC linac has been studied before by Kim et. al. [2]. Since then the proposed target wavelength for t...

H. -d. Nuhn; E. T. Scharlemann; R. Schlter

1995-01-01T23:59:59.000Z

51

Design, Total Chemical Synthesis, and X-Ray Structure of a Protein Having a Novel Linear-Loop Polypeptide Chain Topology  

Science Conference Proceedings (OSTI)

Original synthetic and structure determination methods were used to make a protein molecule with an unprecedented linear-loop polypeptide chain topology, and to characterize its X-ray structure.

Mandal, Kalyaneswar; Pentelute, Brad L.; Bang, Duhee; Gates, Zachary P.; Torbeev, Vladimir Yu.; Kent, Stephen B.H. (UC)

2012-02-10T23:59:59.000Z

52

A gamma- and X-ray detector for cryogenic, high magnetic field applications  

E-Print Network (OSTI)

As part of an experiment to measure the spectrum of photons emitted in beta-decay of the free neutron, we developed and operated a detector consisting of 12 bismuth germanate (BGO) crystals coupled to avalanche photodiodes (APDs). The detector was operated near liquid nitrogen temperature in the bore of a superconducting magnet and registered photons with energies from 5 keV to 1000 keV. To enlarge the detection range, we also directly detected soft X-rays with energies between 0.2 keV and 20 keV with three large area APDs. The construction and operation of the detector is presented, as well as information on operation of APDs at cryogenic temperatures.

Cooper, R L; Bales, M J; Bass, C D; Beise, E J; Breuer, H; Byrne, J; Chupp, T E; Coakley, K J; Dewey, M S; Fu, C; Gentile, T R; Mumm, H P; Nico, J S; O'Neill, B; Pulliam, K; Thompson, A K; Wietfeldt, F E

2012-01-01T23:59:59.000Z

53

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

54

A new bend magnet beam line for scanning transmission x-ray microscopy at the Advanced Light Source  

Science Conference Proceedings (OSTI)

The high brightness of the bend magnets at the Advanced Light Source has been exploited to illuminate a Scanning Transmission X-ray Microscope (STXM). This is the first diffraction-limited scanning x-ray microscope to operate with useful count rate on a synchrotron bend magnet source. A simple, dedicated beam line has been built covering the range of photon energy from 250 eV to 600 eV. Ease of use and operational availability are radically improved compared to previous installations using undulator beams. This facility provides radiation for C 1s, N 1s and O 1s near edge x-ray absorption spectro-microscopy with a spectral resolution up to about 1:5000 and with STXM count rates in excess of 1 MHz.

Warwick, Tony; Ade, Harald; Kilcoyne, A.L. David; Kritscher, Michael; Tylisczcak, Tolek; Fakra, Sirine; Hitchcock, Adam P.; Hitchcock, Peter; Padmore, Howard A.

2001-12-12T23:59:59.000Z

55

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

56

Soft x-ray microscopy - a powerful analytical tool to image magnetism down to fundamental length and times scales  

Science Conference Proceedings (OSTI)

The magnetic properties of low dimensional solid state matter is of the utmost interest both scientifically as well as technologically. In addition to the charge of the electron which is the base for current electronics, by taking into account the spin degree of freedom in future spintronics applications open a new avenue. Progress towards a better physical understanding of the mechanism and principles involved as well as potential applications of nanomagnetic devices can only be achieved with advanced analytical tools. Soft X-ray microscopy providing a spatial resolution towards 10nm, a time resolution currently in the sub-ns regime and inherent elemental sensitivity is a very promising technique for that. This article reviews the recent achievements of magnetic soft X-ray microscopy by selected examples of spin torque phenomena, stochastical behavior on the nanoscale and spin dynamics in magnetic nanopatterns. The future potential with regard to addressing fundamental magnetic length and time scales, e.g. imaging fsec spin dynamics at upcoming X-ray sources is pointed out.

Fischer, Peter

2008-08-01T23:59:59.000Z

57

End station for nanoscale magnetic materials study: Combination of scanning tunneling microscopy and soft X-ray magnetic circular dichroism spectroscopy  

SciTech Connect

We have constructed an end station for nanoscale magnetic materials study at the soft X-ray beamline HiSOR BL-14 at Hiroshima Synchrotron Radiation Center. An ultrahigh-vacuum scanning tunneling microscope (STM) was installed for an in situ characterization of nanoscale magnetic materials in combination with soft X-ray magnetic circular dichroism (XMCD) spectroscopy experiment. The STM was connected to the XMCD experimental station via damper bellows to isolate it from environmental vibrations, thus achieving efficient spatial resolution for observing Si(111) surface at atomic resolution. We performed an in situ experiment with STM and XMCD spectroscopy on Co nanoclusters on an Au(111) surface and explored its practical application to investigate magnetic properties for well-characterized nanoscale magnetic materials.

Ueno, Tetsuro; Sawada, Masahiro; Namatame, Hirofumi [Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046 (Japan); Kishimizu, Yusuke; Kimura, Akio [Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526 (Japan); Taniguchi, Masaki [Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046 (Japan); Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526 (Japan)

2012-12-15T23:59:59.000Z

58

Probing the spin polarization of current by soft x-ray imaging of current-induced magnetic vortex dynamics  

SciTech Connect

Time-resolved soft X-ray transmission microscopy is applied to image the current-induced resonant dynamics of the magnetic vortex core realized in a micron-sized Permalloy disk. The high spatial resolution better than 25 nm enables us to observe the resonant motion of the vortex core. The result also provides the spin polarization of the current to be 0.67 {+-} 0.16 for Permalloy by fitting the experimental results with an analytical model in the framework of the spin-transfer torque.

Kasai, Shinya; Fischer, Peter; Im, Mi-Young; Yamada, Keisuke; Nakatani, Yoshinobu; Kobayashi, Kensuke; Kohno, Hiroshi; Ono, Teruo

2008-12-09T23:59:59.000Z

59

Low-energy x-ray emission from magnetic-fusion plasmas  

SciTech Connect

Complex, transient, spatially inhomogeneous tokamak plasmas require careful diagnosis. As the reactor regime is approached, soft x rays become more important as a versatile diagnostic tool and an energy-loss mechanism. Continuum emission provides a measure of electron temperature and light impurity content. Impurity lines serve as a probe for ion and electron temperature, impurity behavior, and radiative cooling. The entire spectrum yields vital information on instabilities and disruptions. The importance of impurities is illustrated by the extensive efforts toward understanding impurity production, effects, and control. Minute heavy impurity concentrations can prevent reactor ignition. Si(Li) - detector arrays give a broad overview of continuum and line x-ray emission (.3 to 50 keV) with moderate energy (200 eV) and time (50 ms) resolution. Bragg crystal and grating spectrometers provide detailed information on impurity lines with moderate to excellent (E/..delta..E = 100 to 23,000) resolving power and 1 to 50 ms time resolution. Imaging detector arrays measure rapid (approx. 10 ..mu..s) fluctuations due to MHD instabilities and probe impurity behavior and radiative cooling. Future tokamaks require more diagnostic channels to avoid spatial scanning, higher throughput for fast, single-shot diagnosis, increased spectral information per sample period via fast scanning or use of multi-element detectors with dispersive elements, and radiation shielding and hardening of detectors.

Hill, K.W.; Bitter, M.; Eames, D.; von Goeler, S.; Goldman, M.; Sauthoff, N.R.; Silver, E.

1982-04-01T23:59:59.000Z

60

X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation  

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

new materials with new switching mechanisms. Uncovered by basic research into the fundamentals of magnetism, one such candidate consists of miniscule magnetic vortices like...

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

Soft x-ray microscopy - a powerful analytical tool to image magnetism down to fundamental length and times scales  

E-Print Network (OSTI)

of current third generation sources where due to themagnet source at a third generation X-ray synchrotron such

Fischer, Peter

2008-01-01T23:59:59.000Z

62

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...

63

MAGNETIC NON-POTENTIALITY OF SOLAR ACTIVE REGIONS AND PEAK X-RAY FLUX OF THE ASSOCIATED FLARES  

SciTech Connect

Predicting the severity of solar eruptive phenomena such as flares and coronal mass ejections remains a great challenge despite concerted efforts to do so over the past several decades. However, the advent of high-quality vector magnetograms obtained from Hinode (SOT/SP) has increased the possibility of meeting this challenge. In particular, the spatially averaged signed shear angle (SASSA) seems to be a unique parameter for quantifying the non-potentiality of active regions. We demonstrate the usefulness of the SASSA for predicting flare severity. For this purpose, we present case studies of the evolution of magnetic non-potentiality using 115 vector magnetograms of four active regions, namely, ARs NOAA 10930, 10960, 10961, and 10963 during 2006 December 8-15, 2007 June 3-10, 2007 June 28-July 5, and 2007 July 10-17, respectively. The NOAA ARs 10930 and 10960 were very active and produced X and M class flares, respectively, along with many smaller X-ray flares. On the other hand, the NOAA ARs 10961 and 10963 were relatively less active and produced only very small (mostly A- and B-class) flares. For this study, we have used a large number of high-resolution vector magnetograms obtained from Hinode (SOT/SP). Our analysis shows that the peak X-ray flux of the most intense solar flare emanating from the active regions depends on the magnitude of the SASSA at the time of the flare. This finding of the existence of a lower limit of the SASSA for a given class of X-ray flares will be very useful for space weather forecasting. We have also studied another non-potentiality parameter called the mean weighted shear angle (MWSA) of the vector magnetograms along with the SASSA. We find that the MWSA does not show such distinction as the SASSA for upper limits of the GOES X-ray flux of solar flares; however, both the quantities show similar trends during the evolution of all active regions studied.

Tiwari, Sanjiv Kumar; Venkatakrishnan, P.; Gosain, Sanjay, E-mail: pvk@prl.res.i, E-mail: sgosain@prl.res.i [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Bari Road, Udaipur 313 001 (India)

2010-09-20T23:59:59.000Z

64

NEUTRINO-COOLED ACCRETION MODEL WITH MAGNETIC COUPLING FOR X-RAY FLARES IN GAMMA-RAY BURSTS  

Science Conference Proceedings (OSTI)

The neutrino-cooled accretion disk, which was proposed to work as the central engine of gamma-ray bursts, encounters difficulty in interpreting the X-ray flares after the prompt gamma-ray emission. In this paper, the magnetic coupling (MC) between the inner disk and the central black hole (BH) is taken into consideration. For mass accretion rates around 0.001 {approx} 0.1 M{sub Sun} s{sup -1}, our results show that the luminosity of neutrino annihilation can be significantly enhanced due to the coupling effects. As a consequence, after the gamma-ray emission, a remnant disk with mass M{sub disk} {approx}ray flares with the rest frame duration less than 100 s. In addition, a comparison between the MC process and the Blandford-Znajek mechanism is shown on the extraction of BH rotational energy.

Luo Yang; Gu Weimin; Liu Tong; Lu Jufu, E-mail: guwm@xmu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)

2013-08-20T23:59:59.000Z

65

Direct Characterization of Kerogen by X-ray and Solid-State [superscript 13]C Nuclear Magnetic Resonance Methods  

Science Conference Proceedings (OSTI)

A combination of solid-state {sup 13}C NMR, X-ray photoelectron spectroscopy (XPS) and sulfur X-ray absorption near edge structure (S-XANES) techniques are used to characterize organic oxygen, nitrogen, and sulfur species and carbon chemical/structural features in kerogens. The kerogens studied represent a wide range of organic matter types and maturities. A van Krevelen plot based on elemental H/C data and XPS derived O/C data shows the well established pattern for type I, type II, and type III kerogens. The anticipated relationship between the Rock-Eval hydrogen index and H/C is independent of organic matter type. Carbon structural and lattice parameters are derived from solid-state {sup 13}C NMR analysis. As expected, the amount of aromatic carbon, measured by both {sup 13}C NMR and XPS, increases with decreasing H/C. The correlation between aromatic carbon and Rock-Eval T{sub max}, an indicator of maturity, is linear for types II and IIIC kerogens, but each organic matter type follows a different relationship. The average aliphatic carbon chain length (Cn) decreases with an increasing amount of aromatic carbon in a similar manner across all organic matter types. The fraction of aromatic carbons with attachments (FAA) decreases, while the average number of aromatic carbons per cluster (C) increases with an increasing amount of aromatic carbon. FAA values range from 0.2 to 0.4, and C values range from 12 to 20 indicating that kerogens possess on average 2- to 5-ring aromatic carbon units that are highly substituted. There is basic agreement between XPS and {sup 13}C NMR results for the amount and speciation of organic oxygen. XPS results show that the amount of carbon oxygen single bonded species increases and carbonyl-carboxyl species decrease with an increasing amount of aromatic carbon. Patterns for the relative abundances of nitrogen and sulfur species exist regardless of the large differences in the total amount of organic nitrogen and sulfur seen in the kerogens. XPS and S-XANES results indicate that the relative level of aromatic sulfur increases with an increasing amount of aromatic carbon for all kerogens. XPS show that the majority of nitrogen exists as pyrrolic forms in comparable relative abundances in all kerogens studied. The direct characterization results using X-ray and NMR methods for nitrogen, sulfur, oxygen, and carbon chemical structures provide a basis for developing both specific and general average chemical structural models for different organic matter type kerogens.

Kelemen, S. R.; Afeworki, M.; Gorbaty, M.L.; Sansone, M.; Kwiatek, P.J.; Walters, C.C.; Freund, H.; Siskin, M.; Bence, A.E.; Curry, D.J.; Solum, M.; Pugmire, R.J.; Vandenbroucke, M.; Leblond, M.; Behar, F. (ExxonMobil); (ExxonMobil); (IFP); (Utah)

2008-06-12T23:59:59.000Z

66

Direct Characterization of Kerogen By X-Ray And Solid-State **13C Nuclear Magnetic Resonance Methods  

DOE Green Energy (OSTI)

A combination of solid-state {sup 13}C NMR, X-ray photoelectron spectroscopy (XPS) and sulfur X-ray absorption near edge structure (S-XANES) techniques are used to characterize organic oxygen, nitrogen, and sulfur species and carbon chemical/structural features in kerogens. The kerogens studied represent a wide range of organic matter types and maturities. A van Krevelen plot based on elemental H/C data and XPS derived O/C data shows the well established pattern for type I, type II, and type III kerogens. The anticipated relationship between the Rock-Eval hydrogen index and H/C is independent of organic matter type. Carbon structural and lattice parameters are derived from solid-state 13C NMR analysis. As expected, the amount of aromatic carbon, measured by both {sup 13}C NMR and XPS, increases with decreasing H/C. The correlation between aromatic carbon and Rock-Eval Tmax, an indicator of maturity, is linear for types II and IIIC kerogens, but each organic matter type follows a different relationship. The average aliphatic carbon chain length (Cn') decreases with an increasing amount of aromatic carbon in a similar manner across all organic matter types. The fraction of aromatic carbons with attachments (FAA) decreases, while the average number of aromatic carbons per cluster (C) increases with an increasing amount of aromatic carbon. FAA values range from 0.2 to 0.4, and C values range from 12 to 20 indicating that kerogens possess on average 2- to 5-ring aromatic carbon units that are highly substituted. There is basic agreement between XPS and 13C NMR results for the amount and speciation of organic oxygen. XPS results show that the amount of carbon oxygen single bonded species increases and carbonyl-carboxyl species decrease with an increasing amount of aromatic carbon. Patterns for the relative abundances of nitrogen and sulfur species exist regardless of the large differences in the total amount of organic nitrogen and sulfur seen in the kerogens. XPS and S-XANES results indicate that the relative level of aromatic sulfur increases with an increasing amount of aromatic carbon for all kerogens. XPS show that the majority of nitrogen exists as pyrrolic forms in comparable relative abundances in all kerogens studied. The direct characterization results using X-ray and NMR methods for nitrogen, sulfur, oxygen, and carbon chemical structures provide a basis for developing both specific and general average chemical structural models for different organic matter type kerogens.

Keleman, S.R.; Afeworki, M.; Gorbaty, M.L.; Sansone, M.; Kwiatek, P.J.; Walters, C.C.; Freund, H.; Siskin, M.; Bence, A.E.; Curry, D.J.; Solum, M.; Pugmire, R.J.; Vandenbroucke, M.; Leblond, M.; Behar, F.

2007-07-09T23:59:59.000Z

67

How to Turn Carbon into A Magnet? X-rays and Protons Give the...  

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

of the sample using computer software. figure 2 Figure 2: A carbon film is hit by a high-energy proton beam, causing the magnetic moments of the atoms to align around the beam...

68

Advanced characterization of physical properties of coals with different coal structures by nuclear magnetic resonance and X-ray computed tomography  

Science Conference Proceedings (OSTI)

In order to understand the correlation between coal structure and physical property of coal, samples with different coal structures were collected from the Late Permian period coal seams in the Laochang area, Yunnan Province, China. A set of experiments ... Keywords: Adsorption capacities, Coal structure, Nuclear magnetic resonance (NMR), Seepage capacities, X-ray computed tomography (X-CT)

Song Li; Dazhen Tang; Hao Xu; Zi Yang

2012-11-01T23:59:59.000Z

69

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

70

Suppressing Thermal Energy Drift In The LLNL Flash X-Ray Accelerator Using Linear Disk Resistor Stacks  

SciTech Connect

This paper addresses thermal drift in sodium thiosulfate liquid resistors and their replacement with linear disk resistors from HVR Advanced Power Components. Sodium thiosulfate resistors in the FXR induction linear accelerator application have a temperature coefficient of {approx}1.8%/C. The FXR Marx banks send an 8kJ pulse through eight 524 cm{sup 3} liquid resistors at a repetition rate of up to 1 every 45 seconds. Every pulse increases the temperature of the solution by {approx}0.4 C which produces a 0.7% change in resistance. The typical cooling rate is {approx}0.4 C per minute which results in {approx}0.1% energy drop per pulse during continuous pulsed operations. A radiographic accelerator is extraordinarily sensitive to energy variations. Changes in beam energy produce movement in beam transport, changes in spot size, and large dose variations. If self-heating were the only problem, we could predict the increase in input voltage required to compensate for the energy loss. However, there are other variables that influence the temperature of the resistors such as focus magnet heating, changes in room temperature, changes in cooling water, where the cell is located, etc. Additionally not all of the resistors have equivalent cooling rates and as many as 32 resistors are driven from a single power source. The FXR accelerator group elected to replace the sodium thiosulfate resistors with HVR Linear Disk Resistors in a stack type configuration. With data limited for these resistors when used in oil and at low resistance values, a full characterization needed to be performed. High currents (up to 15kA), high voltages (up to 400kV), and Fast Rise times (<10ns) made a resistor choice difficult. Other solid resistors have been tried and had problems at the connection points and with the fact that the resistivity changed as they absorbed oil. The selected HVR resistors have the advantage of being manufactured with the oil impregnated in to them so this characteristic is minimized while still offering the desired low temperature coefficient of resistance compared to sodium thiosulfate. The characterization experiments and comparison with the sodium thiosulfate liquid resistors will be fully discussed and the final design described.

Kreitzer, B R; Houck, T L; Luchterhand, O C

2011-07-19T23:59:59.000Z

71

Structural and magnetic properties of transition metal substituted BaFe{sub 2}As{sub 2} compounds studied by x-ray and neutron scattering  

Science Conference Proceedings (OSTI)

The purpose of my dissertation is to understand the structural and magnetic properties of the newly discovered FeAs-based superconductors and the interconnection between superconductivity, antiferromagnetism, and structure. X-ray and neutron scattering techniques are powerful tools to directly observe the structure and magnetism in this system. I used both xray and neutron scattering techniques on di#11;erent transition substituted BaFe2As2 compounds in order to investigate the substitution dependence of structural and magnetic transitions and try to understand the connections between them.

Kim, Min Gyu [Ames Laboratory

2012-08-28T23:59:59.000Z

72

Magnetocrystalline Anisotropy of Magnetic Grains in Co80Pt20:Oxide Thin Films Probed by X-ray Magnetic Circular Dichroism  

SciTech Connect

Using angle-dependent x-ray magnetic circular dichroism, we have measured magnetic hysteresis loops at the Co L2,3 edges of oxide-doped Co80Pt20 thin films. The magnetocrystalline anisotropy energy (MAE) of the Co atoms, which is the main source of the magnetocrystalline anisotropy of the CoPt magnetic grains, has been determined directly from these element-specific hysteresis loops. When the oxide volume fraction (OVF) is increased from 16.6% to 20.7%, the Co MAE has been found to decrease from 0.117 meV/atom to 0.076 meV/atom. While a larger OVF helps one to achieve a smaller grain size, it reduces the magnetocrystalline anisotropy, as demonstrated unambiguously from the direct Co MAE measurements. Our results suggest that those Co80Pt20:oxide films with an OVF between 19.1% and 20.7% are suitable candidates for high-density magnetic recording.

Zhang, W.; Morton, S. A.; Wong, P. K. J.; Arenholz, E.; Lu, B.; Cheng, T. Y.; Xu, Y. B.; Laan, G. van der; Hu, X.F

2011-01-12T23:59:59.000Z

73

Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system  

SciTech Connect

Purpose: Using hybrid x-ray/MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. Methods: The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also evaluated to determine its stability during acceleration, and a pulse width modulation algorithm was implemented to control the rotation speed of the motor. Results: At a magnetic flux density of 41 mT orthogonal to the axis of rotation (on the lower end of the expected flux density in the MR suite) the maximum speed of the motor was found to be 5150 revolutions per minute (rpm). The acceleration time necessary to reach 3000 rpm was found to be approximately 10 s at 59 mT. The resonance frequency of the assembly with the anode attached was 1310 rpm (21.8 Hz) which is far below the desired operating speeds. Pulse width modulation provides an effective method to control the speed of the motor with a resolution of 100 rpm. Conclusions: The proposed design can serve as a direct replacement to the conventional induction motor used in rotating anode x-ray tubes. It does not suffer from a reduced rotation speed when operating in a MR environment. The presence of chromic steel bearings in the prototype prevented testing at the higher field strengths, and future iterations of the design could eliminate this shortcoming. The prototype assembly demonstrates proof of concept of the authors' design and overcomes one of the major obstacles for a MR compatible rotating anode x-ray tube.

Lillaney, Prasheel; Pelc, Norbert [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States); Shin Mihye [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Hinshaw, Waldo; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Bennett, N. Robert [Department of Radiology, Stanford University, Stanford, California 94305 and Qualcomm MEMS Technologies, San Jose, California 95134 (United States)

2013-02-15T23:59:59.000Z

74

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...

75

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

76

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

77

Observation of coupled vortex gyrations by 70-ps-time and 20-nm-space- resolved full-field magnetic transmission soft x-ray microscopy  

SciTech Connect

We employed time-and space-resolved full-field magnetic transmission soft x-ray microscopy to observe vortex-core gyrations in a pair of dipolar-coupled vortex-state Permalloy (Ni{sub 80}Fe{sub 20}) disks. The 70 ps temporal and 20 nm spatial resolution of the microscope enabled us to simultaneously measure vortex gyrations in both disks and to resolve the phases and amplitudes of both vortex-core positions. We observed their correlation for a specific vortex-state configuration. This work provides a robust and direct method of studying vortex gyrations in dipolar-coupled vortex oscillators.

Jung, Hyunsung; Yu, Young-Sang; Lee, Ki-Suk; Im, Mi-Young; Fischer, Peter; Bocklage, Lars; Vogel, Andreas; Bolte, Markus; Meier, Guido; Kim, Sang-Koog

2010-09-01T23:59:59.000Z

78

Two-temperature accretion flows in magnetic cataclysmic variables: Structures of post-shock emission regions and X-ray spectroscopy  

E-Print Network (OSTI)

We use a two-temperature hydrodynamical formulation to determine the temperature and density structures of the post-shock accretion flows in magnetic cataclysmic variables (mCVs) and calculate the corresponding X-ray spectra. The effects of two-temperature flows are significant for systems with a massive white dwarf and a strong white-dwarf magnetic field. Our calculations show that two-temperature flows predict harder keV spectra than one-temperature flows for the same white-dwarf mass and magnetic field. This result is insensitive to whether the electrons and ions have equal temperature at the shock but depends on the electron-ion exchange rate, relative to the rate of radiative loss along the flow. White-dwarf masses obtained by fitting the X-ray spectra of mCVs using hydrodynamic models including the two-temperature effects will be lower than those obtained using single-temperature models. The bias is more severe for systems with a massive white dwarf.

Saxton, C; Cropper, M; Ramsay, G; Saxton, Curtis; Wu, Kinwah; Cropper, Mark; Ramsay, Gavin

2005-01-01T23:59:59.000Z

79

Soft x-ray microscopy - a powerful analytical tool to image magnetism down to fundamental length and times scales  

E-Print Network (OSTI)

image magnetism down to fundamental length and time scalesmicroscopies have to tackle fundamental magnetic length andregard to addressing fundamental magnetic length and time

Fischer, Peter

2008-01-01T23:59:59.000Z

80

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...

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

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...

82

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

83

Investigations of the R5(SixGe1-x)4 Intermetallic Compounds by X-Ray Resonant Magnetic Scattering  

SciTech Connect

The XRMS experiment on the Gd{sub 5}Ge{sub 4} system has shown that, below the Neel temperature, T{sub N} = 127 K, the magnetic unit cells is the same as the chemical unit cell. From azimuth scans and the Q dependence of the magnetic scattering, all three Gd sites in the structure were determined to be in the same magnetic space group Pnma. The magnetic moments are aligned along the c-axis and the c-components of the magnetic moments at the three different sites are equal. The ferromagnetic slabs are stacked antiferromagnetically along the b-direction. They found an unusual order parameter curve in Gd{sub 5}Ge{sub 4}. A spin-reorientation transition is a possibility in Gd{sub 5}Ge{sub 4}, which is similar to the Tb{sub 5}Ge{sub 4} case. Tb{sub 5}Ge{sub 4} possesses the same Sm{sub 5}Ge{sub 4}-type crystallographic structure and the same magnetic space group as Gd{sub 5}Ge{sub 4} does. The difference in magnetic structure is that Tb{sub 5}Ge{sub 4} has a canted one but Gd{sub 5}Ge{sub 4} has nearly a collinear one in the low temperature antiferromagnetic phase. The competition between the magneto-crystalline anisotropy and the nearest-neighbor magnetic exchange interactions may allow a 3-dimensional canted antiferromagnetic structure in Tb{sub 5}Ge{sub 4}. The spin-reorientation transition in both Gd{sub 5}Ge{sub 4} and Tb{sub 5}Ge{sub 4} may arise from the competition between the magnetic anisotropy from the spin-orbit coupling of the conduction electrons and the dipolar interactions anisotropy.

Lizhi Tan

2008-08-18T23:59:59.000Z

84

DEEP X-RAY OBSERVATIONS OF THE YOUNG HIGH-MAGNETIC-FIELD RADIO PULSAR J1119-6127 AND SUPERNOVA REMNANT G292.2-0.5  

SciTech Connect

High-magnetic-field radio pulsars are important transition objects for understanding the connection between magnetars and conventional radio pulsars. We present a detailed study of the young radio pulsar J1119-6127, which has a characteristic age of 1900 yr and a spin-down-inferred magnetic field of 4.1 Multiplication-Sign 10{sup 13} G, and its associated supernova remnant G292.2-0.5, using deep XMM-Newton and Chandra X-ray Observatory exposures of over 120 ks from each telescope. The pulsar emission shows strong modulation below 2.5 keV with a single-peaked profile and a large pulsed fraction of 0.48 {+-} 0.12. Employing a magnetic, partially ionized hydrogen atmosphere model, we find that the observed pulse profile can be produced by a single hot spot of temperature 0.13 keV covering about one-third of the stellar surface, and we place an upper limit of 0.08 keV for an antipodal hot spot with the same area. The non-uniform surface temperature distribution could be the result of anisotropic heat conduction under a strong magnetic field, and a single-peaked profile seems common among high-B radio pulsars. For the associated remnant G292.2-0.5, its large diameter could be attributed to fast expansion in a low-density wind cavity, likely formed by a Wolf-Rayet progenitor, similar to two other high-B radio pulsars.

Ng, C.-Y.; Kaspi, V. M. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Ho, W. C. G. [School of Mathematics, University of Southampton, Southampton SO17 1BJ (United Kingdom); Weltevrede, P. [Jodrell Bank Centre for Astrophysics, University of Manchester, Alan Turing Building, Manchester M13 9PL (United Kingdom); Bogdanov, S. [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Shannon, R. [CSIRO Astronomy and Space Sciences, Australia Telescope National Facility, Marsfield, NSW 2210 (Australia); Gonzalez, M. E., E-mail: ncy@physics.mcgill.ca [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)

2012-12-10T23:59:59.000Z

85

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

86

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

87

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

88

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

89

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

90

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

91

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

92

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

93

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

94

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

95

Linear Collider Final Focus Magnet Construction | Superconducting Magnet  

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

Linear Collider Final Focus Magnet Construction Linear Collider Final Focus Magnet Construction The final focus magnets for the International Linear Collider require very small quadrupoles be placed within the detector background field for both the entrance and exit beams. The use of superconducting magnets for this function provide solutions to several problems confronting the machine designers. One constraint is the operation within the 3 tesla detector field. The direct wind magnets are capable of operation without the use of magnetic materials in their construction, making them ideal for compact focussing solutions within detectors. The second constraint is the small physical size dictated by the crossing angle of the beams and proximity to the IR within the detector solenoid. The Direct Wind design does not require a collar to withstand Lorentz

96

XTE J1701-462 AND ITS IMPLICATIONS FOR THE NATURE OF SUBCLASSES IN LOW-MAGNETIC-FIELD NEUTRON STAR LOW-MASS X-RAY BINARIES  

SciTech Connect

We report on an analysis of Rossi X-Ray Timing Explorer data of the transient neutron star low-mass X-ray binary (NS-LMXB) XTE J1701-462, obtained during its 2006-2007 outburst. The X-ray properties of the source changed between those of various types of NS-LMXB subclasses. At high luminosities, the source switched between two types of Z source behavior and at low luminosities we observed a transition from Z source to atoll source behavior. These transitions between subclasses primarily manifest themselves as changes in the shapes of the tracks in X-ray color-color (CD) and hardness-intensity diagrams (HID), but they are accompanied by changes in the kHz quasi-periodic oscillations, broadband variability, burst behavior, and/or X-ray spectra. We find that for most of the outburst the low-energy X-ray flux is a good parameter to track the gradual evolution of the tracks in CD and HID, allowing us to resolve the evolution of the source in greater detail than before and relate the observed properties to other NS-LMXBs. We further find that during the transition from Z to atoll, characteristic behavior known as the atoll upper banana can equivalently be described as the final stage of a weakening Z source flaring branch, thereby blurring the line between the two subclasses. Our findings strongly suggest that the wide variety in behavior observed in NS-LXMBs with different luminosities can be linked through changes in a single variable parameter, namely the mass accretion rate, without the need for additional differences in the neutron star parameters or viewing angle. We briefly discuss the implications of our findings for the spectral changes observed in NS-LMXBs and suggest that, contrary to what is often assumed, the position along the color-color tracks of Z sources is not determined by the instantaneous mass accretion rate.

Homan, Jeroen; Fridriksson, Joel K.; Remillard, Ronald A.; Lewin, Walter H. G. [MIT Kavli Institute for Astrophysics and Space Research, 70 Vassar Street, Cambridge, MA 02139 (United States); Van der Klis, Michiel; Wijnands, Rudy; Altamirano, Diego [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Science Park 904, 1098 XH, Amsterdam (Netherlands); Mendez, Mariano [Kapteyn Astronomical Institute, Groningen University, 9700 AV, Groningen (Netherlands); Lin Dacheng [Centre d'Etude Spatiale des Rayonnements, UMR 5187, 9 Av. du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4 (France); Casella, Piergiorgio [School of Physics and Astronomy, University of Southampton, Southampton, Hampshire, SO17 1BJ (United Kingdom); Belloni, Tomaso M., E-mail: jeroen@space.mit.ed [INAF-Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (Italy)

2010-08-10T23:59:59.000Z

97

Three Dimensional X-Ray Scanning Micro/Nano-Diffraction Probe ...  

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...

98

Using High Energy X-ray Experiments and Crystal-Based ...  

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...

99

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.

100

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

Note: This page contains sample records for the topic "x-ray magnetic linear" 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.


101

Heat conduction in X-ray clusters: Spitzer over 3  

E-Print Network (OSTI)

Effective heat conduction in a random variable magnetic field should be equal to one third of the Spitzer's value. Recent observations indicate that this heat conduction is sufficient to account for the bremsstrahlung in cooling X-ray clusters.

Andrei Gruzinov

2002-03-04T23:59:59.000Z

102

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

103

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.

104

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

105

Viewing spin structures with soft x-ray microscopy  

SciTech Connect

The spin of the electron and its associated magnetic moment marks the basic unit for magnetic properties of matter. Magnetism, in particular ferromagnetism and antiferromagnetism is described by a collective order of these spins, where the interaction between individual spins reflects a competition between exchange, anisotropy and dipolar energy terms. As a result the energetically favored ground state of a ferromagnetic system is a rather complex spin configuration, the magnetic domain structure. Magnetism is one of the eldest scientific phenomena, yet it is one of the most powerful and versatile utilized physical effects in modern technologies, such as in magnetic storage and sensor devices. To achieve highest storage density, the relevant length scales, such as the bit size in disk drives is now approaching the nanoscale and as such further developments have to deal with nanoscience phenomena. Advanced characterization tools are required to fully understand the underlying physical principles. Magnetic microscopes using polarized soft X-rays offer a close-up view into magnetism with unique features, these include elemental sensitivity due to X-ray magnetic dichroism effects as contrast mechanism, high spatial resolution provided by state-of-the-art X-ray optics and fast time resolution limited by the inherent time structure of current X-ray sources, which will be overcome with the introduction of ultrafast and high brilliant X-ray sources.

Fischer, Peter

2010-06-01T23:59:59.000Z

106

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

107

Linear-response and real-time time-dependent density functional theory studies of core-level near-edge x-ray absorption  

Science Conference Proceedings (OSTI)

We discuss our implementation and application of time-dependent density functional theory (TDDFT) to core-level near-edge absorption spectroscopy, using both linear-response (LR) and real-time (RT) approaches. We briefly describe our restricted window TDDFT (REWTDDFT) approach for core excitations which has also been reported by others groups. This is followed by a detailed discussion of real-time TDDFT techniques tailored to core excitations, including obtaining spectral information through delta-function excitation, post-processing time-dependent signals, and resonant excitation through quasi-monochromatic excitation. We present results for the oxygen K-edge of water and carbon dioxide; the carbon K-edge of carbon dioxide; the ruthenium L3-edge for the hexaamminerutheium(III) ion, including scalar relativistic corrections via the zeroth order regular approximation (ZORA); and the carbon and fluorine K-edges for a series of fluorobenzenes. In all cases, the calculated spectra are found to be in good agreement with experiment, requiring only a uniform shift on the order of a few percent. Real-time TDDFT visualization of excited state charge densities are used to visually examine the nature of each excitation, which gives insight into the effects of atoms bound to the absorbing center.

Lopata, Kenneth A.; Van Kuiken, Benjamin E.; Khalil, Munira; Govind, Niranjan

2012-09-03T23:59:59.000Z

108

X-ray magnetic circular dichroism of ferromagnetic Co{sub 4}N epitaxial films on SrTiO{sub 3}(001) substrates grown by molecular beam epitaxy  

Science Conference Proceedings (OSTI)

5-nm thick Co{sub 4}N layers capped with 3-nm thick Au layers were grown epitaxially on SrTiO{sub 3}(001) substrates by molecular beam epitaxy using solid Co and a radio-frequency NH{sub 3} plasma. Spin and orbital magnetic moments of the Co{sub 4}N layers were estimated using x-ray magnetic circular dichroism (XMCD) measurements at 300 K. The site-averaged Co 3d spin magnetic moment is evaluated to be about 1.4 {mu}{sub B}, which is smaller than that predicted theoretically (1.58 {mu}{sub B}). The element-specific XMCD intensities for the Co L{sub 3} edge and N K edge show that the magnetic moment is induced at the N atoms.

Ito, Keita; Harada, Kazunori; Toko, Kaoru; Suemasu, Takashi [Institute of Applied Physics, University of Tsukuba, Ibaraki 305-8573 (Japan); Ye, Mao; Kimura, Akio [Graduate School of Science, Hiroshima University, Hiroshima 739-8526 (Japan); Takeda, Yukiharu; Saitoh, Yuji [Japan Atomic Energy Agency (JAEA), SPring-8, Hyogo 679-5198 (Japan); Akinaga, Hiro [National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki 305-8569 (Japan)

2011-12-19T23:59:59.000Z

109

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 ...

110

Fast-switching elliptically polarized soft X-ray beam X13A at NSLS  

SciTech Connect

The X13A beamline at NSLS is dedicated to the generation and uses of fast-switching elliptically polarized soft X-ray radiation in the energy range from 250 to {approx}1600 eV. The source for this beamline is an elliptically polarized wiggler (EPW) that delivers linearly elliptically polarized soft X-rays at a switching rate, between right- and left-handed polarization, up to 100 Hz. The optical design is a spherical grating monochromator (SGM) that focuses and diffracts in plane orthogonal to the polarization switching direction. The X13A beamline scientific program is dedicated to spectroscopy and scattering studies of magnetism and magnetic materials. The fast-switching capability of the EPW enables the use of lock-in techniques, thereby greatly enhancing the detection sensitivity for small polarization-dependent signals.

Sanchez-Hanke, C.; Kao, C.; Hulbert, S.

2009-07-21T23:59:59.000Z

111

Exploring nanomagnetism with soft x-ray microscopy  

SciTech Connect

Magnetic soft X-ray microscopy images magnetism in nanoscale systems with a spatial resolution down to 15nm provided by state-of-the-art Fresnel zone plate optics. X-ray magnetic circular dichroism (X-MCD) is used as element-specific magnetic contrast mechanism similar to photoemission electron microscopy (PEEM), however, with volume sensitivity and the ability to record the images in varying applied magnetic fields which allows to study magnetization reversal processes at fundamental length scales. Utilizing a stroboscopic pump-probe scheme one can investigate fast spin dynamics with a time resolution down to 70 ps which gives access to precessional and relaxation phenomena as well as spin torque driven domain wall dynamics in nanoscale systems. Current developments in zone plate optics aim for a spatial resolution towards 10nm and at next generation X-ray sources a time resolution in the fsec regime can be envisioned.

Fischer, P.; Kim, D.-H.; Mesler, B.L.; Chao, W.; Sakdinawat,A.E.; Anderson, E.H.

2006-10-30T23:59:59.000Z

112

Chandra X-ray Observatory Detection of Extended X-ray Emission from the Planetary Nebula BD+303639  

E-Print Network (OSTI)

We report the detection of well resolved, extended X-ray emission from the young planetary nebula BD+303639 using the Advanced CCD Imaging Spectrometer (ACIS) aboard the Chandra X-ray Observatory. The X-ray emission from BD+303639 appears to lie within, but is concentrated to one side of, the interior of the shell of ionized gas seen in high-resolution optical and IR images. The relatively low X-ray temperature (Tx ~ 3x10^6 K) and asymmetric morphology of the X-ray emission suggests that conduction fronts are present and/or mixing of shock-heated and photoionized gas has occurred and, furthermore, hints at the presence of magnetic fields. The ACIS spectrum suggests that the X-ray emitting region is enriched in the products of helium burning. Our detection of extended X-ray emission from BD+303639 demonstrates the power and utility of Chandra imaging as applied to the study of planetary nebulae.

Kstner, J H; Vrtilek, S D; Dgani, R; Kastner, Joel H.; Soker, Noam; Vrtilek, Saeqa; Dgani, Ruth

2000-01-01T23:59:59.000Z

113

Chandra X-ray Observatory Detection of Extended X-ray Emission from the Planetary Nebula BD+303639  

E-Print Network (OSTI)

We report the detection of well resolved, extended X-ray emission from the young planetary nebula BD+303639 using the Advanced CCD Imaging Spectrometer (ACIS) aboard the Chandra X-ray Observatory. The X-ray emission from BD+303639 appears to lie within, but is concentrated to one side of, the interior of the shell of ionized gas seen in high-resolution optical and IR images. The relatively low X-ray temperature (Tx ~ 3x10^6 K) and asymmetric morphology of the X-ray emission suggests that conduction fronts are present and/or mixing of shock-heated and photoionized gas has occurred and, furthermore, hints at the presence of magnetic fields. The ACIS spectrum suggests that the X-ray emitting region is enriched in the products of helium burning. Our detection of extended X-ray emission from BD+303639 demonstrates the power and utility of Chandra imaging as applied to the study of planetary nebulae.

Joel H. Kastner; Noam Soker; Saeqa Vrtilek; Ruth Dgani

2000-10-09T23:59:59.000Z

114

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

115

X-ray diffuse scattering measurements of chemical short-range order and lattice strains in a highly magnetostrictive Fe0.813Ga0.187 alloy in an applied magnetic field  

SciTech Connect

The rapid growth of the magnetostriction coefficient of ferromagnetic Fe1?xGax alloys that occurs at a composition range from 0magnetic field, thereby resulting in a large magnetoelastic response. X-ray diffuse scattering measurements sensitive to the atomic short-range ordering and lattice strain were performed on a quenched 18.7 at. % Ga alloy and show no dependence on the application of a magnetic field. This negative result sets limits on the role of nanoscale precipitates in magnetostriction.

Du, Yingzhou; Lograsso, Thomas A.; McQueeney, Robert J.

2012-06-28T23:59:59.000Z

116

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

117

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

118

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

119

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

120

Design Concept and Performance of the Soft X-ray Beamline HiSOR-BL14  

SciTech Connect

The soft X-ray beamline HiSOR-BL14 has been constructed at Hiroshima Synchrotron Radiation Center, aimed at absorption spectroscopy and photoelectron spectroscopy with linearly and circularly polarized light. The beamline layout is based on a Dragon-type design with a spherical grating monochromator. The beamline is able to accept synchrotron radiation from the bending magnet part of the HiSOR ring with a wide solid angle. The large horizontal angular acceptance and vertical one contribute to high photon flux and controllability of light polarization, respectively. Our performance test indicates that high resolving power has been achieved with sufficient photon flux to carry out spectroscopic experiments.

Sawada, M.; Namatame, H. [Hiroshima Synchrotron Radiation Center, Hiroshima University, Kagamiyama 2-313, Higashi-Hiroshima, Hiroshima 739-0046 (Japan); Yaji, K. [Institute for Solid State Physics, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8581 (Japan); Nagira, M.; Kimura, A.; Taniguchi, M. [Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-0046 (Japan)

2007-01-19T23:59:59.000Z

Note: This page contains sample records for the topic "x-ray magnetic linear" 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.


121

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

122

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

123

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

124

Imaging X-ray Thomson Scattering Spectrometer Design and Demonstration  

SciTech Connect

In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering is a powerful technique for measuring these plasma parameters. However, the scattered signal has previously been measured with little or no spatial resolution, which limits the ability to diagnose inhomogeneous plasmas. We report on the development of a new imaging x-ray Thomson spectrometer (IXTS) for the Omega laser facility. The diffraction of x-rays from a toroidally-curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile while spectrally dispersing the radiation. This focusing geometry allows for high brightness while localizing noise sources and improving the linearity of the dispersion. Preliminary results are presented from a scattering experiment that used the IXTS to measure the temperature profile of a shocked carbon foam.

Gamboa, E.J. [University of Michigan; Huntington, C.M. [University of Michigan; Trantham, M.R. [University of Michigan; Keiter, P.A [University of Michigan; Drake, R.P. [University of Michigan; Montgomery, David [Los Alamos National Laboratory; Benage, John F. [Los Alamos National Laboratory; Letzring, Samuel A. [Los Alamos National Laboratory

2012-05-04T23:59:59.000Z

125

Laser assisted Compton scattering of X-ray photons  

E-Print Network (OSTI)

The Compton scattering of X-ray photons, assisted by a short intense optical laser pulse is discussed. The differential scattering cross section reveals the interesting feature that the main Klein-Nishina line is accompanied by a series of side-lines forming a broad plateau where up to ${\\cal O} (10^3)$ laser photons participate simultaneously in a single scattering event. Due to the non-linear mixing of X-ray and laser photons a frequency dependent rotation of the polarization of the final state photons relative to the scattering plane emerges. A consistent description of the scattering process with short laser pulses requires to work with X-ray pulses. An experimental investigation can be accomplished, e.g., at LCLS or the European XFEL in the near future.

D. Seipt; B. Kampfer

2013-09-09T23:59:59.000Z

126

Linear Collider Final Focus Magnet Construction | Superconducting Magnet  

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

Six Layer Quadrupole Six Layer Quadrupole The incoming beam final quad for the linear collider 20 mr option requires a gradient of 140 T/m within a solenoid of 3 Tesla. To meet this goal, a design using 6 around 1 cable bonded to a one inch diameter tube was used. The magnet design required 6 layers of this cable. Two layers were bonded at a time, with S-glass compression wrap every two layers. Final cold testing results were very good, with only two training quenches before reaching short sample. Initial test results at a glance: Background Field Tesla Temp Kelvin Gradient T/m 3 4.3 158 4 4.22 139 5 4.22 134 6 3 137 This data scales to 232 Tesla/meter at 1.9 Kelvin in a 3 Tesla background field. Present field requirements for the 20 mr IR represents 60% of the magnet capability, a comfortable margin. Indeed, even at 4.3 Kelvin in a 3

127

Photon Sciences | Beamlines | XPD: X-ray Powder Diffraction  

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

XPD: X-ray Powder Diffraction XPD: X-ray Powder Diffraction Poster | Fact Sheet | Preliminary Design Report Scientific Scope XPD is a tunable facility with the ability to collect diffraction data at high x-ray energies (40keV-80keV), offering rapid acquisition (millisecond) and high angular resolution capabilities on the same instrument. XPD addresses future scientific challenges in, for example, hydrogen storage, CO2 sequestration, advanced structural ceramics, catalysis, and materials processing. Such materials of high technological value often are complex, nanostructured and heterogeneous. The scientific grand challenge is to obtain robust and quantitative (micro)structural information, not only in the ground state at ambient conditions, but also in situ or in operando with varying temperature, pressure, magnetic/electric/stress

128

Neutron and X-Ray Scattering - Argonne National Laboratories, Materials  

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

Home Home Neutron and X-Ray Scattering Neutron and X-ray Scattering Science Recent advances in neutron and x-ray scattering instrumentation at major DOE facilities such as the Spallation Neutron Source and Advanced Photon Source provide unprecedented insights into complex phenomena in bulk and interfacial materials. The vision of our group is to harness the complementarity of neutrons and x-rays to study how materials respond on a range of length and time scales to phase competition, so that we can learn to control emergent behavior and generate functional properties in energy-related materials. We use neutrons and x-rays to investigate the structure and dynamics of bulk and interfacial materials with properties that are useful for energy applications, such as superconductivity, magnetism and thermoelectricity. Phase competition can generate or enhance such properties, but it is extremely challenging to characterize fluctuations in the competing order, whether in bulk disordered materials, or artificial heterostructures. Our goal is to utilize efficient techniques that we have been developing for measuring nanoscale phase fluctuations, both static and dynamic, to enable the rational design of new materials for energy within MSD.

129

Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor  

DOE Patents (OSTI)

A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle leviation.

Coffey, Howard T. (Darien, IL)

1993-01-01T23:59:59.000Z

130

Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor  

DOE Patents (OSTI)

A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle levitation. 3 figures.

Coffey, H.T.

1993-10-19T23:59:59.000Z

131

Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor  

DOE Patents (OSTI)

A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle leviation.

Coffey, H.T.

1992-12-31T23:59:59.000Z

132

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

133

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

134

X-ray diffraction study, magnetic susceptibility, and electric properties of Cu{sub 3}Fe{sub 0.5}Se{sub 2} crystal  

Science Conference Proceedings (OSTI)

Single crystals of the Cu{sub 3}Fe{sub 0.5}Se{sub 2} composition have been grown. The orthorhombic lattice parameters are found to be a = 8.169 A, b = 8.238 A, c = 12.052 A, V = 811.15 A{sup 3}, D{sub x} = 6.23 g/cm{sup 3}, sp. gr. Pnma, Z = 8. The magnetic susceptibility is measured in the range 100 < T < 400 K at H = 2 T. It is established that a crystal transforms into the antiferromagnetic state below T{sub N} = 350 K. The temperature dependences of the electrical conduction ({sigma}), thermal electromotive force ({alpha}), and thermal conduction (k) are measured in the range 80 < T < 400 K; the n value was calculated to be 5 x 10{sup 19} cm{sup -1}.

Guseinov, G. G., E-mail: g.guseinov@rambler.ru; Ragimov, S. S.; Hasani Barbaran, J.; Agamirzoeva, G. M. [National Academy of Sciences, Institute of Physics (Azerbaijan)

2010-07-15T23:59:59.000Z

135

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

136

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

137

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...

138

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 ...

139

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

140

Imaging of lateral spin valves with soft x-ray microscopy  

SciTech Connect

We investigated Co/Cu lateral spin valves by means of high-resolution transmission soft x-ray microscopy with magnetic contrast that utilizes x-ray magnetic circular dichroism (XMCD). No magnetic XMCD contrast was observed at the Cu L{sub 3} absorption edge, which should directly image the spin accumulation in Cu. Although electrical transport measurements in a non-local geometry clearly detected the spin accumulation in Cu, which remained unchanged during illumination with circular polarized x-rays at the Co and Cu L{sub 3} absorption edges.

Mosendz, O.; Mihajlovic, G.; Pearson, J. E.; Fischer, P.; Im, M.-Y.; Bader, S. D.; Hoffmann, A.

2009-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

Novel Approach to Linear Accelerator Superconducting Magnet System  

SciTech Connect

Superconducting Linear Accelerators include a superconducting magnet system for particle beam transportation that provides the beam focusing and steering. This system consists of a large number of quadrupole magnets and dipole correctors mounted inside or between cryomodules with SCRF cavities. Each magnet has current leads and powered from its own power supply. The paper proposes a novel approach to magnet powering based on using superconducting persistent current switches. A group of magnets is powered from the same power supply through the common, for the group of cryomodules, electrical bus and pair of current leads. Superconducting switches direct the current to the chosen magnet and close the circuit providing the magnet operation in a persistent current mode. Two persistent current switches were fabricated and tested. In the paper also presented the results of magnetic field simulations, decay time constants analysis, and a way of improving quadrupole magnetic center stability. Such approach substantially reduces the magnet system cost and increases the reliability.

Kashikhin, Vladimir; /Fermilab

2011-11-28T23:59:59.000Z

142

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

143

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

144

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)

145

A low-power-extended-linear-range magnetic levitator  

E-Print Network (OSTI)

In this thesis, I designed and built analog circuits to extend the linear range of a magnetic levitator. Analog Devices AD633 multipliers are used to implement nonlinear terms which compensate for the electromagnet and ...

Johnson, Rayal St. Patrick

2007-01-01T23:59:59.000Z

146

Cryogen free superconducting splittable quadrupole magnet for linear accelerators  

SciTech Connect

A new superconducting quadrupole magnet for linear accelerators was fabricated at Fermilab. The magnet is designed to work inside a cryomodule in the space between SCRF cavities. SCRF cavities must be installed inside a very clean room adding issues to the magnet design, and fabrication. The designed magnet has a splittable along the vertical plane configuration and could be installed outside of the clean room around the beam pipe previously connected to neighboring cavities. For more convenient assembly and replacement a 'superferric' magnet configuration with four racetrack type coils was chosen. The magnet does not have a helium vessel and is conductively cooled from the cryomodule LHe supply pipe and a helium gas return pipe. The quadrupole generates 36 T integrated magnetic field gradient, has 600 mm effective length, and the peak gradient is 54 T/m. In this paper the quadrupole magnetic, mechanical, and thermal designs are presented, along with the magnet fabrication overview and first test results.

Kashikhin, V.S.; Andreev, N.; Kerby, J.; Orlov, Y.; Solyak, N.; Tartaglia, M.; Velev, G.; /Fermilab

2011-09-01T23:59:59.000Z

147

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.

148

Using X-ray mammograms to assist in microwave breast image interpretation  

Science Conference Proceedings (OSTI)

Current clinical breast imaging modalities include ultrasound, magnetic resonance (MR) imaging, and the ubiquitous X-ray mammography. Microwave imaging, which takes advantage of differing electromagnetic properties to obtain image contrast, shows potential ...

Charlotte Curtis; Richard Frayne; Elise Fear

2012-01-01T23:59:59.000Z

149

Soft x-ray diagnostics for pulsed power machines  

SciTech Connect

A variety of soft x-ray diagnostics are being fielded on the Los Alamos National Laboratory Pegasus and Procyon pulsed power systems and also being fielded on joint US/Russian magnetized target fusion experiments known as MAGO (Magnitoye Obzhatiye). The authors have designed a low-cost modular photoemissive detector designated the XRD-96 that uses commercial 1100 series aluminum for the photocathode. In addition to photocathode detectors a number of designs using solid state silicon photodiodes have been designed and fielded. They also present a soft x-ray time-integrated pinhole camera system that uses standard type TMAX-400 photographic film that obviates the need for expensive and no longer produced zero-overcoat soft x-ray emulsion film. In a typical experiment the desired spectral energy cuts, signal intensity levels, and desired field of view will determine diagnostic geometry and x-ray filters selected. The authors have developed several computer codes to assist in the diagnostic design process and data deconvolution. Examples of the diagnostic design process and data analysis for a typical pulsed power experiment are presented.

Idzorek, G.C.; Coulter, W.L.; Walsh, P.J.; Montoya, R.R.

1995-08-01T23:59:59.000Z

150

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.

151

XIPE: the X-ray Imaging Polarimetry Explorer  

E-Print Network (OSTI)

X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and temporal variability measurements and to imaging, allows a wealth of physical phenomena in astrophysics to be studied. X-ray polarimetry investigates the acceleration process, for example, including those typical of magnetic reconnection in solar flares, but also emission in the strong magnetic fields of neutron stars and white dwarfs. It detects scattering in asymmetric structures such as accretion disks and columns, and in the so-called molecular torus and ionization cones. In addition, it allows fundamental physics in regimes of gravity and of magnetic field intensity not accessible to experiments on the Earth to be probed. Finally, models that describe fundamental interactions (e.g. quantum gravity and the extension of the Standard Model) can be tested. We describe in this paper the X-ray Imaging Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a small mission with a launch in 2017 but not selected. XIPE ...

Soffitta, Paolo; Bellazzini, Ronaldo; Braga, Joo; Costa, Enrico; Fraser, George W; Gburek, Szymon; Huovelin, Juhani; Matt, Giorgio; Pearce, Mark; Poutanen, Juri; Reglero, Victor; Santangelo, Andrea; Sunyaev, Rashid A; Tagliaferri, Gianpiero; Weisskopf, Martin; Aloisio, Roberto; Amato, Elena; Attin, Primo; Axelsson, Magnus; Baldini, Luca; Basso, Stefano; Bianchi, Stefano; Blasi, Pasquale; Bregeon, Johan; Brez, Alessandro; Bucciantini, Niccol; Burderi, Luciano; Burwitz, Vadim; Casella, Piergiorgio; Churazov, Eugene; Civitani, Marta; Covino, Stefano; da Silva, Rui Miguel Curado; Cusumano, Giancarlo; Dadina, Mauro; D'Amico, Flavio; De Rosa, Alessandra; Di Cosimo, Sergio; Di Persio, Giuseppe; Di Salvo, Tiziana; Dovciak, Michal; Elsner, Ronald; Eyles, Chris J; Fabian, Andrew C; Fabiani, Sergio; Feng, Hua; Giarrusso, Salvatore; Goosmann, Ren W; Grandi, Paola; Grosso, Nicolas; Israel, Gianluca; Jackson, Miranda; Kaaret, Philip; Karas, Vladimir; Kuss, Michael; Lai, Dong; La Rosa, Giovanni; Larsson, Josefin; Larsson, Stefan; Latronico, Luca; Maggio, Antonio; Maia, Jorge; Marin, Frdric; Massai, Marco Maria; Mineo, Teresa; Minuti, Massimo; Moretti, Elena; Muleri, Fabio; O'Dell, Stephen L; Pareschi, Giovanni; Peres, Giovanni; Pesce, Melissa; Petrucci, Pierre-Olivier; Pinchera, Michele; Porquet, Delphine; Ramsey, Brian; Rea, Nanda; Reale, Fabio; Rodrigo, Juana Maria; R?a?ska, Agata; Rubini, Alda; Rudawy, Pawel; Ryde, Felix; Salvati, Marco; Jnior, Valdivino Alexandre de Santiago; Sazonov, Sergey; Sgr, Carmelo; Silver, Eric; Spandre, Gloria; Spiga, Daniele; Stella, Luigi; Tamagawa, Toru; Tamborra, Francesco; Tavecchio, Fabrizio; Dias, Teresa Teixeira; van Adelsberg, Matthew; Wu, Kinwah; Zane, Silvia

2013-01-01T23:59:59.000Z

152

New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution  

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

New Zone Plate for Soft X-Ray New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Wednesday, 31 August 2005 00:00 Analytical tools that combine spatial resolution with elemental and chemical identification at the nanometer scale along with large penetration depth are indispensable for the life and physical sciences. The XM-1 soft x-ray microscope at the ALS produces images that not only reveal structures but can identify their chemical elements and measure magnetic and other properties as well. Now a new method for creating optical devices with nanoscale accuracy has allowed researchers in Berkeley Lab's Center for X-Ray Optics (CXRO), which built and operates the XM-1, to achieve an extraordinary resolution of better than 15 nm, with the promise of even higher resolution in the near future.

153

A fine-focusing x-ray source using carbon-nanofiber field emitter  

Science Conference Proceedings (OSTI)

A fine-focusing x-ray source has been constructed employing a field electron emitter prepared by growing carbon-nanofibers (CNFs) on a metal tip. The x-ray source is composed of a CNF field electron emitter, an electrostatic lens, two magnetic lenses, and a W-target for generating x-rays by electron impact. The CNFs provided field electrons with a current density of J{approx}5x10{sup 9} A/m{sup 2}, which was evaluated with the aid of Fowler-Nordheim theory. The electron beam extracted from the CNF emitter was accelerated to the energies of E=10-25 keV, and then focused by the lenses. By recording the x-ray images of test charts, the optimum resolution of the x-ray source was estimated to be approximately D{sub x}=0.5 {mu}m.

Sugimoto, W.; Sugita, S.; Sakai, Y.; Goto, H.; Watanabe, Y.; Ohga, Y.; Kita, S. [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Ohara, T. [Topcon Corporation, 75-1 Hasunuma-cho, Itabashi-ku, Tokyo 174-8580 (Japan)

2010-08-15T23:59:59.000Z

154

Soft x-ray undulator for the Siam Photon Source  

SciTech Connect

An undulator for production of intense soft x-rays has been designed for the Siam Photon Source. The construction of the undulator has been completed. It is now being characterized and prepared for installation. The device, named U60, is a pure permanent magnet planar undulator, consisting of 41 magnetic periods, with 60 mm period length. Utilization of the undulator radiation in the photon energy range of 30 - 900 eV is expected. The design studies of the magnetic structure, including investigation of perturbations arising from the magnetic field of the device, their effects on the SPS storage ring and compensation schemes are described. A magnetic measurement system has been constructed for magnetic characterization of the device. Partial results of magnetic measurements are presented.

Rugmai, S. [National Synchrotron Research Center, P.O. Box 93, Nakhon Ratchasima, 30000 (Thailand); School of Physics, Suranaree University of Technology, 111 University Avenue, Muang Distrct, Nakhon Ratchasima, 30000 (Thailand); Dasri, T. [School of Physics, Suranaree University of Technology, 111 University Avenue, Muang Distrct, Nakhon Ratchasima, 30000 (Thailand); Prawanta, S.; Siriwattanapaitoon, S.; Kwankasem, A.; Sooksrimuang, V.; Chachai, W.; Suradet, N.; Juthong, N.; Tancharakorn, S. [National Synchrotron Research Center, P.O. Box 93, Nakhon Ratchasima, 30000 (Thailand)

2007-01-19T23:59:59.000Z

155

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

156

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

157

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

158

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,...

159

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

160

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...

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

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...

162

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

163

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.

164

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.

165

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.

166

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.

167

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

168

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

169

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.

170

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

171

Linear Collider Final Focus Magnet Construction | Superconducting Magnet  

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

Two Layer Quadrupole Shielding Coil Two Layer Quadrupole Shielding Coil Near the interaction region if the ILC, the exit beam by design, is very close to the final focus quads, and is sensitive to the external field of the quads. To eliminate this effect and prevent disruption of the exiting beams, a two layer shielding quadrupole has been designed and wound. For simplicity as well as efficiency, the transfer function of this coilset has been designed to allow series connection of the focus quad with this outer shield coilset. The completed magnet will be finished with G-10 fillers, voltage taps and heaters will be added, blue epoxy filling for all interstitial spaces, and then the magnet will be wrapped with glass cloth and fiberglass roving, then cured. Once cured, this magnet will be capable of full power operation

172

An X-ray Polarimeter for Constellation-X  

E-Print Network (OSTI)

Polarimetry remains a largely unexploited technique in observational X-ray astronomy which could provide insight in the study of the strong gravity and magnetic fields at the core of the Constellation-X observational program. Adding a polarization capability to the Constellation-X instrumentation would be immensely powerful. It would make Constellation the first space observatory to simultaneously measure all astrophysically relevant parameters of source X-ray photons; their position (imaging), energy (spectroscopy), arrival time (timing), and polarization. Astrophysical polarimetry requires sensitive well-calibrated instruments. Many exciting objects are extra-galactic (i.e. faint) and may have small polarization. Recent advances in efficiency and bandpass make it attractive to consider a polarimetry Science Enhancement Package for the Constellation-X mission.

K. Jahoda; K. Black; P. Deines-Jones; J. E. Hill; T. Kallman; T. Strohmayer; J. H. Swank

2007-01-04T23:59:59.000Z

173

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

174

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...

175

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

176

Dopant Site Determination in Iron Oxide Nanoparticles Utilizing X-ray  

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

Dopant Site Determination in Iron Oxide Nanoparticles Utilizing X-ray Dopant Site Determination in Iron Oxide Nanoparticles Utilizing X-ray Absorption Techniques Monday, September 9, 2013 - 11:00am SLAC, Conference Room 137-322 Presented by Dr. Vanessa Pool The dopant behavior of spinels has been investigated for over half a century and yet new insight into this class of materials is still being made today. In this work, the question of dopant site preference is explored for the nanoparticle regime. Iron oxide nanoparticles have numerous exciting applications. To realize these applications, controlling the preferred dopant site and valence within the host material is important. X-ray Absorption Spectroscopy (XAS) and X-ray Magnetic Circular Dichroism (XMCD) are element specific techniques with magnetic contrast that give insights into the material composition. Using both

177

Adaptive friction compensation for permanent magnet linear synchronous motor  

Science Conference Proceedings (OSTI)

The paper discussed an adaptive friction compensation scheme based on Coulomb friction and a parameter identifier. The model reference adaptive system based on Coulomb friction was designed to compensate the friction on-line. The designed model reference ... Keywords: friction compensation, model reference adaptive control, parameter identification, permanent magnet linear synchronous motor (PMLSM)

Wang Li-Mei; Wu Lin

2009-06-01T23:59:59.000Z

178

Linear Collider Final Focus Magnet Construction | Superconducting Magnet  

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

Single Strand Superconductor Windings Single Strand Superconductor Windings Initial direct wind quad coils were constructed using 13 mil diameter single strand wire. This wire provides the smallest coil patterns possible, with quad coils wound easily onto .75 inch (19mm) diameter support tubes. The 13mil diameter superconductor gives the smallest coils possible, the penalty being higher inductance and smaller transfer function, but allowing lower operational currents. long model magnet Figure 1 shows the first one foot long model magnet constructed using the 11 axis ultrasonic wiring machine with 13 mil superconducting wire, the same wire previously used for the 472 RHIC Corrector packages. Existing stock materials were used in the construction, and the coil pattern was not optimized for harmonics, but to put as many coil turns onto the tube as

179

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

180

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

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

THz Pump and X-Ray Probe Development at LCLS  

Science Conference Proceedings (OSTI)

We report on measurements of broadband, intense, coherent transition radiation at terahertz frequencies, generated as the highly compressed electron bunches in Linear Coherent Light Source (LCLS) pass through a thin metal foil. The foil is inserted at 45{sup o} to the electron beam, 31 m downstream of the undulator. The THz emission passes downward through a diamond window to an optical table below the beamline. A fully compressed 350-pC bunch produces up to 0.5 mJ in a nearly half-cycle pulse of 50 fs FWHM with a spectrum peaking at 10 THz. We estimate a peak field at the focus of over 2.5 GV/m. A 20-fs Ti:sapphire laser oscillator has recently been installed for electro-optic measurements. We are developing plans to add an x-ray probe to this THz pump, by diffracting FEL x rays onto the table with a thin silicon crystal. The x rays would arrive with an adjustable time delay after the THz. This will provide a rapid start to user studies of materials excited by intense single-cycle pulses and will serve as a step toward a THz transport line for LCLS-II.

Fisher, Alan S; /SLAC, LCLS; Durr, Hermann; /SIMES, Stanford /SLAC, PULSE; Lindenberg, Aaron; Stanford U., Materials Sci.Dept.; /SIMES, Stanford /SLAC, PULSE; Reis, David; /SIMES, Stanford /SLAC, PULSE /Stanford U., Dept. Appl. Phys.; Frisch, Josef; Loos, Henrik; Petree, Mark; /SLAC, LCLS; Daranciang, Dan; /Stanford U., Chem. Dept.; Fuchs, Matthias; /SLAC, PULSE; Ghimire, Shambhu; /SLAC, PULSE; Goodfellow, John; /Stanford U., Materials Sci. Dept.

2011-11-08T23:59:59.000Z

182

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.

183

X-RAY OBSERVATIONS OF HIGH-B RADIO PULSARS  

SciTech Connect

The study of high-magnetic-field pulsars is important for examining the relationships between radio pulsars, magnetars, and X-ray-isolated neutron stars (XINSs). Here, we report on X-ray observations of three such high-magnetic-field radio pulsars. We first present the results of a deep XMM-Newton observation of PSR J1734-3333, taken to follow up on its initial detection in 2009. The pulsar's spectrum is well fit by a blackbody with a temperature of 300 {+-} 60 eV, with bolometric luminosity L{sub bb}=2.0{sub -0.7}{sup +2.2} Multiplication-Sign 10{sup 32} erg s{sup -1}{approx}0.0036 E-dot for a distance of 6.1 kpc. We detect no X-ray pulsations from the source, setting a 1{sigma} upper limit on the pulsed fraction of 60% in the 0.5-3 keV band. We compare PSR J1734-3333 to other rotation-powered pulsars of similar age and find that it is significantly hotter, supporting the hypothesis that the magnetic field affects the observed thermal properties of pulsars. We also report on XMM-Newton and Chandra observations of PSRs B1845-19 and J1001-5939. We do not detect either pulsar, setting 3{sigma} upper limits on their blackbody temperatures of 48 and 56 eV, respectively. Despite the similarities in rotational properties, these sources are significantly cooler than all but one of the XINSs, which we attribute to the two groups having been born with different magnetic fields and hence evolving differently.

Olausen, S. A.; Kaspi, V. M. [Department of Physics, Rutherford Physics Building, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8 (Canada)] [Department of Physics, Rutherford Physics Building, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8 (Canada); Zhu, W. W. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada)] [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada); Vogel, J. K. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States)] [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Lyne, A. G.; Espinoza, C. M.; Stappers, B. W. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)] [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Manchester, R. N. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Epping, NSW 1710 (Australia)] [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Epping, NSW 1710 (Australia); McLaughlin, M. A. [Department of Physics, West Virginia University, White Hall, Morgantown, WV 26506 (United States)] [Department of Physics, West Virginia University, White Hall, Morgantown, WV 26506 (United States)

2013-02-10T23:59:59.000Z

184

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

185

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

186

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

187

Absolute, soft x-ray calorimetry on the Z facility at Sandia National Laboratories  

SciTech Connect

Simple and reliable x-ray fluence measurements, in addition to time-resolved diagnostics, are needed to understand the physics of hot Z-pinch plasmas. A commercially available laser calorimeter has been modified for measuring soft x-ray fluence from the Z facility at Sandia National Laboratories. The x-ray absorber of this calorimeter is an aluminum disk, attached to a two-dimensional thermopile and surrounded by an isoperibol shroud. The time-integral and the maximum of the thermopile voltage signal are both proportional to the x-ray energy deposited. Data are collected for 90 seconds, and the instrument has, thus far, been used in the 1--25 mJ range. A wider dynamic measuring range for x-ray fluence (energy/area) can be achieved by varying the area of the defining aperture. The calorimeter is calibrated by an electrical substitution method. Calibrations are performed before and after each x-ray experiment on the Z facility. The calibration of the time-integral of the thermopile voltage vs. energy deposited (or the peak of thermopile voltage vs. energy deposited) is linear with zero offset at the 95% confidence level. The irreproducibility of the calibration is <2%, and the imprecision in the measurement of the incident x-ray energy (inferred from signal noise and the calibration) is estimated to be {approximately}0.9 mJ (95% confidence level). The inaccuracy is estimated at {+-}10%, due to correctable systematic errors (e.g., baseline shifts). Comparisons have been made of the calorimeter to time-resolved x-ray diagnostics, e.g., bolometers and XRD (x-ray diode) arrays, by integrating the flux measured by these instruments over time.

Fehl, D.L.; Muron, D.J.; Leeper, R.J.; Chandler, G.A.; Deeney, C.; Spielman, R.B.

1998-05-01T23:59:59.000Z

188

Direct x-ray response of self-scanning photodiode arrays  

SciTech Connect

Self-scanning photodiode arrays were tested for their ability to measure the spatial distribution of low-energy x rays in a wavelength-dispersive spectrometer. X-ray spectral sensitivity was measured with a calibrated dc source of nearly-monochromatic characteristic-x rays with photon energies in the range of 1.5 to 8 keV. Photodiode response was found to be linear with x-ray flux. Exposure to large doses of copper radiation did not affect sensitivity. A mathematical model that describes the experimental data is presented. It was found that spatial resolving power was lowered by the dispersal of photogenerated charges. This effect was investigated with collimated beams and is described with a formula that predicts the loss of diode signals. (auth)

Koppel, L.N.

1975-08-13T23:59:59.000Z

189

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

SciTech Connect

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

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

2011-01-12T23:59:59.000Z

190

New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution  

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

New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Analytical tools that combine spatial resolution with elemental and chemical identification at the nanometer scale along with large penetration depth are indispensable for the life and physical sciences. The XM-1 soft x-ray microscope at the ALS produces images that not only reveal structures but can identify their chemical elements and measure magnetic and other properties as well. Now a new method for creating optical devices with nanoscale accuracy has allowed researchers in Berkeley Lab's Center for X-Ray Optics (CXRO), which built and operates the XM-1, to achieve an extraordinary resolution of better than 15 nm, with the promise of even higher resolution in the near future.

191

X Ray Scattering | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

X Ray Scattering X Ray Scattering Materials Sciences and Engineering (MSE) Division MSE Home About Research Areas Energy Frontier Research Centers (EFRCs) DOE Energy Innovation Hubs BES Funding Opportunities The Computational Materials and Chemical Sciences Network (CMCSN) Theoretical Condensed Matter Physics Scientific Highlights Reports and Activities Principal Investigators' Meetings BES Home Research Areas X Ray Scattering Print Text Size: A A A RSS Feeds FeedbackShare Page This activity supports basic research on the fundamental interactions of photons with matter to achieve an understanding of atomic, electronic, and magnetic structures and excitations and their relationships to materials properties. The main emphasis is on x-ray scattering, spectroscopy, and imaging research, primarily at major BES-supported user facilities.

192

New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution  

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

New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Analytical tools that combine spatial resolution with elemental and chemical identification at the nanometer scale along with large penetration depth are indispensable for the life and physical sciences. The XM-1 soft x-ray microscope at the ALS produces images that not only reveal structures but can identify their chemical elements and measure magnetic and other properties as well. Now a new method for creating optical devices with nanoscale accuracy has allowed researchers in Berkeley Lab's Center for X-Ray Optics (CXRO), which built and operates the XM-1, to achieve an extraordinary resolution of better than 15 nm, with the promise of even higher resolution in the near future.

193

Schmahl, Kirz Receive Compton Award for Contributions to X-ray Microscopy  

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

Schmahl, Kirz Received Compton Award for Contributions to X-ray Microscopy Schmahl, Kirz Received Compton Award for Contributions to X-ray Microscopy Image of Compton Award The Advanced Photon Source (APS) and APS Users Organization (APSUO) are very pleased to announce that the 2005 Arthur H. Compton Award was given to Günter Schmahl and Janos Kirz for pioneering and developing the field of x-ray microscopy using Fresnel zone plates. Because of their leadership over the last 30 years, x-ray microscopy has evolved into a powerful method for the study of nanoscale structures and phenomena in many areas of science. Their achievements have opened up productive research avenues in biology, polymers, electronic nanostructures, magnetic materials, meteoritics, and environmental sciences. " Günter Schmahl and Janos Kirz have created a

194

New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution  

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

New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Analytical tools that combine spatial resolution with elemental and chemical identification at the nanometer scale along with large penetration depth are indispensable for the life and physical sciences. The XM-1 soft x-ray microscope at the ALS produces images that not only reveal structures but can identify their chemical elements and measure magnetic and other properties as well. Now a new method for creating optical devices with nanoscale accuracy has allowed researchers in Berkeley Lab's Center for X-Ray Optics (CXRO), which built and operates the XM-1, to achieve an extraordinary resolution of better than 15 nm, with the promise of even higher resolution in the near future.

195

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

196

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

197

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

198

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

199

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.

200

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

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


201

X-Ray 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.

202

Soft X-Ray Imaging of spin dynamics at high spatial and temporalresolution  

Science Conference Proceedings (OSTI)

Soft X-ray microscopy provides element specific magnetic imaging with a spatial resolution down to 15nm. At XM-1, the full-field soft X-ray microscope at the Advanced Light Source in Berkeley, a stroboscopic pump and probe setup has been developed to study fast magnetization dynamics in ferromagnetic elements with a time resolution of 70ps which is set by the width of the X-ray pulses from the synchrotron. Results obtained with a 2 {micro}m x 4 {micro}m x 45nm rectangular permalloy sample exhibiting a seven domain Landau pattern reveal dynamics up to several nsec after the exciting magnetic field pulse. Domain wall motion, a gyrotropic vortex motion, and a coupling between vortices in the rectangular geometry are observed.

Mesler, Brooke L.; Fischer, Peter; Chao, Weilun; Anderson, Erik H.

2007-06-01T23:59:59.000Z

203

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

204

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

205

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

206

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

207

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

208

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,

209

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-

210

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

211

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

212

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

213

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

214

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

215

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...

216

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...

217

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...

218

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...

219

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...

220

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

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

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...

222

SOLAR POLAR X-RAY JETS AND MULTIPLE BRIGHT POINTS: EVIDENCE FOR SYMPATHETIC ACTIVITY  

SciTech Connect

We present an analysis of X-ray bright points (BPs) and X-ray jets observed by Hinode/X-Ray Telescope on 2007 November 2-4, within the solar northern polar coronal hole. After selecting small subregions that include several BPs, we followed their brightness evolution over a time interval of a few hours, when several jets were observed. We find that most of the jets occurred in close temporal association with brightness maxima in multiple BPs: more precisely, most jets are closely correlated with the brightening of at least two BPs. We suggest that the jets result from magnetic connectivity changes that also induce the BP variability. We surmise that the jets and implied magnetic connectivity we describe are small-scale versions of the active-region-scale phenomenon, whereby flares and eruptions are triggered by interacting bipoles.

Pucci, Stefano; Romoli, Marco [Department of Physics and Astronomy, University of Firenze, Firenze (Italy); Poletto, Giannina [INAF-Arcetri Astrophysical Observatory, Firenze (Italy); Sterling, Alphonse C., E-mail: stpucci@arcetri.astro.it [Space Science Office, VP 62, Marshall Space Flight Center, Huntsville, AL 35812 (United States)

2012-02-15T23:59:59.000Z

223

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.

224

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.

225

Image plates as x-ray detectors in plasma physics experiments  

SciTech Connect

The performance of image plates based on the photostimulable phosphor BaF(Br,l):Eu{sup 2+} has been investigated and compared with x-ray film. Evaluation of detective quantum efficiency (DQE), sensitivity, dynamic range, and linearity was carried out for several types of commercially available image plate, using the Excalibur soft x-ray calibration facility at AWE. Image plate response was found to be linear over a dynamic range of 5 orders of magnitude. One type of image plate was found to have a number of advantages for soft x-ray detection, with a measured sensitivity 1 order of magnitude greater than that of Kodak Industrex CX and DEF-5 x-ray film. The DQE of this plate was found to be superior to that of film at low [less than 10{sup 3} photons/(50 {mu}m){sup 2}] and high fluxes [greater than 10{sup 4} photons/(50 {mu}m){sup 2}]. The spatial resolution of image plates, scanned with several models of commercial image plate readers, has been evaluated using a USAF resolution test target. The highest spatial resolution measured is 35 {mu}m. Though this is significantly lower than the resolution possible with film, it is sufficient for many applications. Image plates were fielded in a refractive x-ray lens imaging diagnostic on the 1 TW Helen laser and these results are discussed.

Gales, S.G.; Bentley, C.D. [AWE Aldermaston, Reading RG7 4PR (United Kingdom)

2004-10-01T23:59:59.000Z

226

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

227

Anomalous X-ray Diffraction Studies for Photovoltaic Applications  

DOE Green Energy (OSTI)

Anomalous X-ray Diffraction (AXRD) has become a useful technique in characterizing bulk and nanomaterials as it provides specific information about the crystal structure of materials. In this project we present the results of AXRD applied to materials for photovoltaic applications: ZnO loaded with Ga and ZnCo{sub 2}O{sub 4} spinel. The X-ray diffraction data collected for various energies were plotted in Origin software. The peaks were fitted using different functions including Pseudo Voigt, Gaussian, and Lorentzian. This fitting provided the integrated intensity data (peaks area values), which when plotted as a function of X-ray energies determined the material structure. For the first analyzed sample, Ga was not incorporated into the ZnO crystal structure. For the ZnCo{sub 2}O{sub 4} spinel Co was found in one or both tetrahedral and octahedral sites. The use of anomalous X-ray diffraction (AXRD) provides element and site specific information for the crystal structure of a material. This technique lets us correlate the structure to the electronic properties of the materials as it allows us to probe precise locations of cations in the spinel structure. What makes it possible is that in AXRD the diffraction pattern is measured at a number of energies near an X-ray absorption edge of an element of interest. The atomic scattering strength of an element varies near its absorption edge and hence the total intensity of the diffraction peak changes by changing the X-ray energy. Thus AXRD provides element specific structural information. This method can be applied to both crystalline and liquid materials. One of the advantages of AXRD in crystallography experiments is its sensitivity to neighboring elements in the periodic tables. This method is also sensitive to specific crystallographic phases and to a specific site in a phase. The main use of AXRD in this study is for transparent conductors (TCs) analysis. TCs are considered to be important materials because of their efficiency and low risk of environmental pollution. These materials are important to solar cells as a result of their remarkable combination of optical and electrical properties, including high electrical conductivity and high optical transparency in the spectrum of visible light. TCs provide a transparent window, which allows sunlight to pass through while also allowing electricity to conduct out of the cell. Spinel materials have the chemical form AB{sub 2}O{sub 4}, and are made of a face-centered cubic (FCC) lattice of oxygen anions and cations in specific interstitial sites. A normal spinel has all A cations on tetrahedral sites and B cations on octahedral sites. In contrast; an inverse spinel has the A and half of the B cations on octahedral sites and the other half of the B cations on tetrahedral sites; a mixed spinel lies between. In the spinel structure, 8 of 64 possible tetrahedral sites and 16 of 32 possible octahedral sites are filled. Normal spinels have particularly high conduction as the linear octahedral chains of B cations likely serve as conduction paths. In this paper we present how the data obtained with AXRD is used to analyze TCs properties as they apply to photovoltaic applications. One of the materials used for this analysis is zinc oxide. It has been loaded with 5% and 10% of Ga, which has an absorption edge of 10367 eV. The peak (100) was measured for the zinc oxide loaded with 10% Ga. In the case of 5% Ga, we measured peaks (100) and (101). With the information provided by the AXRD we can identify if Ga is being incorporated in the ZnO crystal structure. The analysis of 311 plane in the ZnCo{sub 2}O{sub 4} spinel shows if Co is in tetrahedral or octahedral site.

Not Available

2011-06-22T23:59:59.000Z

228

Simulated X-Ray Absorption Spectroscopy on the Water Dimer  

DOE Green Energy (OSTI)

The ability of an individual H{sub 2}O molecule to form multiple hydrogen bonds with neighboring molecules makes it an ideal substance for the study of hydrogen bonding. X-ray absorption spectroscopy (XAS) can be used to study what intermolecular structures the hydrogen-bonded water molecules form. XAS excites core electrons from the oxygen 1 s atomic orbital to an unoccupied orbital. The resulting absorption spectrum shows the energy levels of the unoccupied orbitals, which in turn is dependent on the intermolecular structure of the H{sub 2}O system. Previous studies using molecular dynamics computer simulations have concluded that the intermolecular structure of liquid water is a distorted tetrahedron. Yet x-ray absorption spectra show discrepancies between liquid water and ice Ih, which is already known to have a rigid tetrahedral structure. The research group, which is based in the University of Sweden in Stockholm and the Stanford Synchrotron Radiation Laboratory at the Stanford Linear Accelerator Center, has studied the possible presence of broken hydrogen bonds in the liquid water intermolecular structure to explain these deviations. Computer simulations are used to construct theoretical absorption spectra for models of liquid water including broken hydrogen bonds. Creating such models requires controlling variables. The simplest method of isolating individual variables, such as hydrogen bond length and angles, is to study the water dimer. Here, the water dimer is used to study how the absorption spectra change with the way the water molecules are positioned and oriented relative to each other.

Wung, A

2004-02-05T23:59:59.000Z

229

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

230

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

231

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

232

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

233

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

234

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.

235

Alcator C-Mod soft X-ray pulse height analysis system  

E-Print Network (OSTI)

A pulse height analysis (PHA) system has been installed on the Alcator C-Mod magnetic confinement fusion experiment. The PHA utilizes a Si(Li) detector to measure soft X-rays in the 1-30 keV range with an energy resolution ...

Gamboa, Eliseo (Eliseo J.)

2007-01-01T23:59:59.000Z

236

An Observer-Based Design for Cogging Forces Cancellation in Permanent Magnet Linear Motors  

E-Print Network (OSTI)

An Observer-Based Design for Cogging Forces Cancellation in Permanent Magnet Linear Motors Jérémy magnet (PM) linear motors, in presence of spatially periodic forces, also known as cogging. Using cleanliness of operation and better resistance to wear and tear. Ironless motors feature two magnetic tracks

Paris-Sud XI, Université de

237

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

238

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

239

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

240

Are X-ray Clusters Cooled by Heat Conduction to the Surrounding Intergalactic Medium?  

E-Print Network (OSTI)

We show that X-ray clusters would have cooled substantially over a Hubble time by transport of heat from their hot interior to the their envelope, if the heat conductivity had not been heavily suppressed relative to the Spitzer value due to magnetic fields. The suppression is required in order for the observed abundance of hot X-ray clusters to be consistent with predictions from popular cosmological models. If a similar or stronger suppression factor applies to cluster cores, then thermal conduction can not be the mechanism that prevents cooling flows there.

Abraham Loeb

2002-03-26T23:59:59.000Z

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241

Non-Invasive Early Detection and Molecular Analysis of Low X-ray Dose  

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

Invasive Early Detection & Molecular Analysis of Low X-ray Dose Effects Invasive Early Detection & Molecular Analysis of Low X-ray Dose Effects in the Lens Lee Goldstein Boston University School of Medicine Abstract Purpose: The lens is a highly-ordered tissue with unique optical properties and exquisite radiosensitivity. The focus of this project is to evaluate radiation cataract dose response and mechanisms associated with low-linear energy transfer (LET) X-rays. We aim to investigate the natural history of Rayleigh light scattering changes in pre-cataractous lenses of mice exposed to radiations using a fully-validated, performance-tested quasi-elastic light scattering (QLS) instrument developed by Dr. Goldstein and colleagues at Boston University. This innovative laser-based technology quantitatively assays pre-cataractous molecular pathology in the lenses of living mice

242

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

243

Scanning Transmission X-ray Microscopy: Applications in Atmospheric Aerosol Research  

Science Conference Proceedings (OSTI)

Scanning transmission x-ray microscopy (STXM) combines x-ray microscopy and near edge x-ray absorption fine structure spectroscopy (NEXAFS). This combination provides spatially resolved bonding and oxidation state information. While there are reviews relevant to STXM/NEXAFS applications in other environmental fields (and magnetic materials) this chapter focuses on atmospheric aerosols. It provides an introduction to this technique in a manner approachable to non-experts. It begins with relevant background information on synchrotron radiation sources and a description of NEXAFS spectroscopy. The bulk of the chapter provides a survey of STXM/NEXAFS aerosol studies and is organized according to the type of aerosol investigated. The purpose is to illustrate the current range and recent growth of scientific investigations employing STXM-NEXAFS to probe atmospheric aerosol morphology, surface coatings, mixing states, and atmospheric processing.

Moffet, Ryan C.; Tivanski, Alexei V.; Gilles, Mary K.

2011-01-20T23:59:59.000Z

244

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

245

Performance evaluation of a permanent magnet brushless DC linear drive for high-speed machining using finite element analysis  

Science Conference Proceedings (OSTI)

Keywords: FEA, coupled magneto-thermal, electric field, electromagnetic, linear motor drives, magnetic field, static

George Abdou; William Tereshkovich

2000-05-01T23:59:59.000Z

246

Total x-ray power measurements in the Sandia LIGA program.  

SciTech Connect

Total X-ray power measurements using aluminum block calorimetry and other techniques were made at LIGA X-ray scanner synchrotron beamlines located at both the Advanced Light Source (ALS) and the Advanced Photon Source (APS). This block calorimetry work was initially performed on the LIGA beamline 3.3.1 of the ALS to provide experimental checks of predictions of the LEX-D (LIGA Exposure- Development) code for LIGA X-ray exposures, version 7.56, the version of the code in use at the time calorimetry was done. These experiments showed that it was necessary to use bend magnet field strengths and electron storage ring energies different from the default values originally in the code in order to obtain good agreement between experiment and theory. The results indicated that agreement between LEX-D predictions and experiment could be as good as 5% only if (1) more accurate values of the ring energies, (2) local values of the magnet field at the beamline source point, and (3) the NIST database for X-ray/materials interactions were used as code inputs. These local magnetic field value and accurate ring energies, together with NIST database, are now defaults in the newest release of LEX-D, version 7.61. Three dimensional simulations of the temperature distributions in the aluminum calorimeter block for a typical ALS power measurement were made with the ABAQUS code and found to be in good agreement with the experimental temperature data. As an application of the block calorimetry technique, the X-ray power exiting the mirror in place at a LIGA scanner located at the APS beamline 10 BM was measured with a calorimeter similar to the one used at the ALS. The overall results at the APS demonstrated the utility of calorimetry in helping to characterize the total X-ray power in LIGA beamlines. In addition to the block calorimetry work at the ALS and APS, a preliminary comparison of the use of heat flux sensors, photodiodes and modified beam calorimeters as total X-ray power monitors was made at the ALS, beamline 3.3.1. This work showed that a modification of a commercially available, heat flux sensor could result in a simple, direct reading beam power meter that could be a useful for monitoring total X-ray power in Sandia's LIGA exposure stations at the ALS, APS and Stanford Synchrotron Radiation Laboratory (SSRL).

Malinowski, Michael E. (Sandia National Laboratories, Livermore, CA); Ting, Aili (Sandia National Laboratories, Livermore, CA)

2005-08-01T23:59:59.000Z

247

13th International Conference on Magnetically Levitated Systems and Linear Drives  

Science Conference Proceedings (OSTI)

This report contains short papers on research being conducted throughout the world on magnetically levitated systems, mainly consisting of trains, and magnetic linear drives. These papers have been index separately elsewhere on the data base.

Not Available

1993-09-01T23:59:59.000Z

248

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

249

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.

250

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

251

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

252

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

253

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

254

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.

255

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.

256

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.

257

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

258

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

259

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,

260

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 "x-ray magnetic linear" 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

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

262

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

263

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

264

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

Science Conference Proceedings (OSTI)

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

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

2006-02-01T23:59:59.000Z

265

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

266

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...

267

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...

268

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

269

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...

270

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

271

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.

272

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

273

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

274

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:...

275

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 ...

276

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...

277

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 ...

278

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

279

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...

280

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 "x-ray magnetic linear" 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

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

282

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...

283

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...

284

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 ...

285

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

286

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

287

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...

288

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...

289

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

290

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...

291

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....

292

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...

293

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 ...

294

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...

295

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...

296

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

297

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...

298

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

299

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

300

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

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

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

302

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

303

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

304

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

305

X-rays from T Tau: A test case for accreting T Tauri stars  

E-Print Network (OSTI)

We test models for the generation of X-rays in accreting T Tauri stars (TTS), using X-ray data from the classical TTS T Tau. High-resolution spectroscopy from the Reflection Grating Spectrometers on XMM-Newton is used to infer electron densities, element abundances and the thermal structure of the X-ray source. We also discuss the ultraviolet light curve obtained by the Optical Monitor, and complementary ground-based photometry. A high-resolution image from Chandra constrains contributions from the two companions of T Tau N. The X-ray grating spectrum is rich in emission lines, but shows an unusual mixture of features from very hot (~30 MK) and very cool (1-3 MK) plasma, both emitted by similar amounts of emission measure. The cool plasma confirms the picture of a soft excess in the form of an enhanced OVII/OVIII Lya flux ratio, similar to that previously reported for other accreting TTS. Diagnostics from lines formed by this plasma indicate low electron densities (cool ``soft-excess'' plasma is orders of magnitude below that predicted for an accretion shock, assuming previously determined accretion rates of (3-6)E-8 M_sun/y. We argue that loading of magnetic field lines with infalling material suppresses the heating process in a part of the corona. We thus suggest that the X-ray production of T Tau is influenced by the accretion process although the X-rays may not form in the bulk of the accretion footpoints.

M. Guedel; S. L. Skinner; S. Yu. Mel'nikov; M. Audard; A. Telleschi; K. R. Briggs

2006-12-20T23:59:59.000Z

306

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

307

Optimization of a dual acting, magnetically driven, linear actuator  

E-Print Network (OSTI)

In this study the geometry of a dual acting, magnetically driven, linear motion actuator will be optimized. This will be accomplished by modeling the system through a set of differential equations to be solved in Matlab. An ANSYS finite element program will be used to model the thermal response of the electrical coils so a maximum temperature can be found. These simulations will be part of a Matlab optimization routine. This routine will optimize the actuator's geometry by minimizing a cost function comprised of the floater displacement, the actuator weight, and the maximum coil temperature. Different simulations will be run, each with a unique set of operating parameters. These tests will be analyzed and an optimal configuration will be found. Once complete, a different approach in meeting the design objectives of a stroke length of at least 10 mils, a low maximum coil temperature and a low actuator weight, will be taken. Instead of optimizing the geometry, the rubber pads that are found between the ECOREs and the floater will be replaced by a classical PID type controller. The effects that this PID controller has on the actuator response in reference to the design objectives will be noted and discussed. During the geometrical optimization, an optimal configuration was found that increases the stroke length of the actuator from approximately 1.01 mils to 2.24 mils. However, by implementing a PID control scheme and keeping the rubber pads, with a stiffness of 2854 lb/in, in the system, this stroke length can be increased to 30 mils. It is recommended that the geometry be changed to geometry found in iteration 53 of optimization trial 4 in conjunction with a PID control scheme. This best satisfies the design objectives.

Willerton, Justin Ryan

2002-01-01T23:59:59.000Z

308

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

309

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

310

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

311

The Neutron Stars of Soft X-Ray Transients  

E-Print Network (OSTI)

Soft X-ray Transients (SXRTs) have long been suspected to contain old, weakly magnetic neutron stars that have been spun up by accretion torques. After reviewing their observational properties, we analyse the different regimes that likely characterise the neutron stars in these systems across the very large range of mass inflow rates, from the peak of the outbursts to the quiescent emission. While it is clear that close to the outburst maxima accretion onto the neutron star surface takes place, as the mass inflow rate decreases, accretion might stop at the magnetospheric boundary because of the centrifugal barrier provided by the neutron star. For low enough mass inflow rates (and sufficiently short rotation periods), the radio pulsar mechanism might turn on and sweep the inflowing matter away. The origin of the quiescent emission, observed in a number of SXRTs at a level of ~10^(32)-10^(33) erg/s, plays a crucial role in constraining the neutron star magnetic field and spin period. Accretion onto the neutron...

Campana, S; Mereghetti, S; Stella, L; Tavani, M

1998-01-01T23:59:59.000Z

312

Focused ion beam patterned Fe thin films A study by selective area Stokes polarimetry and soft x-Ray microscopy  

Science Conference Proceedings (OSTI)

We demonstrate the potential to modify the magnetic behavior and structural properties of ferromagnetic thin films using focused ion beam 'direct-write' lithography. Patterns inspired by the split-ring resonators often used as components in meta-materials were defined upon 15 nm Fe films using a 30 keV Ga{sup +} focused ion beam at a dose of 2 x 10{sup 16} ions cm{sup -2}. Structural, chemical and magnetic changes to the Fe were studied using transmission soft X-ray microscopy at the ALS, Berkeley CA. X-ray absorption spectra showed a 23% reduction in the thickness of the film in the Ga irradiated areas, but no chemical change to the Fe was evident. X-ray images of the magnetic reversal process show domain wall pinning around the implanted areas, resulting in an overall increase in the coercivity of the film. Transmission electron microscopy showed significant grain growth in the implanted regions.

Cook, P. J.; Shen, T. H.; Grundy, P. J.; Im, M.-Y.; Fischer, P.; Morton, S. A.; Kilcoyne, A. L. D.

2010-11-14T23:59:59.000Z

313

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

314

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

315

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

316

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

317

Magnet-only loudspeaker motors: linear behavior theory vs. Nonlinear measurements  

E-Print Network (OSTI)

Magnet-only loudspeaker motors: linear behavior theory vs. Nonlinear measurements A. Novaka and B, the exclusive use of permanent magnets and the absence of iron can lead to uniform motor parameters (force [6] presented loudspeaker distortion reduction us- ing bonded magnet-only motors. Advantages

Paris-Sud XI, Université de

318

Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams  

SciTech Connect

The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present preliminary results at the LCLS from a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (boron carbide in this system) intercepts the beam. The pulse heating of the target material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy. The thermal acoustic detector is designed to provide first- and second-order calorimetric measurement of X-ray FEL pulse energy. The first-order calorimetry is a direct temperature measurement of a target designed to absorb all or most of the FEL pulse power with minimal heat leak. The second-order measurement detects the vibration caused by the rapid thermoelastic expansion of the target material each time it absorbs a photon pulse. Both the temperature change and the amplitude of the acoustic signal are directly related to the photon pulse energy.

Smith, T.J.; Frisch, J.C.; Kraft, E.M.; Loos, J.; /SLAC; Bentsen, G.S.; /Rochester U.

2011-12-13T23:59:59.000Z

319

NSLS X-Ray Storage Ring  

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

magnetic fields on the lattice are minimized, the brightness is optimized for short high- field wigglers, and the low vertical beta function allows the development of very small...

320

Radio emission in clusters and connection to X-ray emission  

E-Print Network (OSTI)

The most spectacular aspect of cluster radio emission is represented by the large-scale diffuse radio sources, which cannot be obviously associated with any individual galaxy. These sources demonstrate the existence of relativistic particles and magnetic fields in the cluster volume, thus indicating the presence of non-thermal processes in the hot intracluster medium. The knowledge of the properties of these sources has increased significantly in recent years, owing to sensitive radio images and to the development of theoretical models. An important piece of information on the origin and evolution of these sources can be obtained by the cluster X-ray emission of thermal origin, and by its relation to the radio emission. Moreover, non-thermal X-ray emission of inverse Compton origin gives direct information on the energy density of radio emitting particles and the intensity of magnetic field.

Luigina Feretti

2007-12-13T23:59:59.000Z

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

X-ray source safety shutter  

DOE Patents (OSTI)

An apparatus is provided for controlling the activation of a high energy radiation source having a shutter. The apparatus includes magnets and magnetically responsive switches appropriately placed and interconnected so that only with the shutter and other parts of the source in proper position can safe emission of radiation out an open shutter occur.

Robinet, McLouis (Oak Park, IL)

1977-05-31T23:59:59.000Z

322

Biological Imaging by Soft X-Ray Diffraction Microscopy  

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

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

323

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.

324

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

325

X-ray emission from laser-produced plasmas  

SciTech Connect

The intensity and spectral characteristics of x-ray emitted from laser-produced plasmas have been investigated computatinoally and experimentally. a two-dimensional implosi code was used successfully to calculate laser-plasma radiation characteristics and to aid in the design of laser targets for high-yield x-ray production. Other computer codes, in use or under development predict lime strengths and energies for laser-plasma x-ray emission. An experimental effort is aimed at reliable measurements of x-ray yields and spectra. a wide variety of x-ray detection methods have been evaluated, and x-ray yields have been measured from plasmas produced with two dissimilar laser systems. The high energy x-ray spectrum, from about 10 to 140 keV, has been studied using high-gain scintillatino detectors and thick K-edge filters. Various supplementary measurements have provided information concerning characteristics of the target-reflected laser light, the ion energies, and the laser intensity patterns.

Violet, C.E. [ed.

1974-07-01T23:59:59.000Z

326

Direct three-dimensional coherently scattered x-ray microtomography  

Science Conference Proceedings (OSTI)

Purpose: It has been shown that coherently scattered x rays can be used to discriminate and identify specific components in a mixture of low atomic weight materials. The authors demonstrated a new method of doing coherently scattered x-ray tomography with a thin sheet of x ray. Methods: A collimated x-ray fan-beam, a parallel polycapillary collimator, and a phantom consisting of several biocompatible materials of low attenuation-based contrast were used to investigate the feasibility of the method. Because of the particular experimental setup, only the phantom translation perpendicular to the x-ray beam is needed and, thus, there is no need of Radon-type tomographic reconstruction, except for the correction of the attenuation to the primary and scattered x rays, which was performed by using a conventional attenuation-based tomographic image data set. The coherent scatter image contrast changes with momentum transfer among component materials in the specimen were investigated with multiple x-ray sources with narrow bandwidth spectra generated with anode and filter combinations of Cu/Ni (8 keV), Mo/Zr (18 keV), and Ag/Pd (22 keV) and at multiple scatter angles by orienting the detector and polycapillary collimator at different angles to the illuminating x ray. Results: The contrast among different materials changes with the x-ray source energy and the angle at which the image was measured. The coherent scatter profiles obtained from the coherent scatter images are consistent with the published results. Conclusions: This method can be used to directly generate the three-dimensional coherent scatter images of small animal, biopsies, or other small objects with low atomic weight biological or similar synthetic materials with low attenuation contrast. With equipment optimized, submillimeter spatial resolution may be achieved.

Cui Congwu; Jorgensen, Steven M.; Eaker, Diane R.; Ritman, Erik L. [Department of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street Southwest, Alfred Building 2-409, Rochester, Minnesota 55905 (United States)

2010-12-15T23:59:59.000Z

327

Optical systems for synchrotron radiation: lecture 4. Soft x-ray imaging systems  

Science Conference Proceedings (OSTI)

The history and present techniques of soft x-ray imaging are reviewed briefly. The physics of x-ray imaging is described, including the temporal and spatial coherence of x-ray sources. Particular technologies described are: contact x-ray microscopy, zone plate imaging, scanned image zone plate microscopy, scanned image reflection microscopy, and soft x-ray holography and diffraction. (LEW)

Howells, M.R.

1986-04-01T23:59:59.000Z

328

Astrophysics of the Soft Gamma Repeaters and Anomalous X-Ray Pulsars  

E-Print Network (OSTI)

I summarize the recent advances in our understanding of the Soft Gamma Repeaters: in particular their spin behavior, persistent emission and hyper-Eddington outbursts. The giant flares on 5 March 1979 and 27 August 1998 provide compelling physical evidence for magnetic fields stronger than 10 B_{QED} = 4.4 x 10^{14} G, consistent with the rapid spindown detected in two of these sources. The persistent X-ray emission and variable spindown of the 6-12 s Anomalous X-ray Pulsars are compared and contrasted with those of the SGRs, and the case made for a close connection between the two types of sources. Their collective properties point to the existence of {\\it magnetars}: neutron stars in which a decaying magnetic field (rather than accretion or rotation) is the dominant source of energy for radiative and particle emissions. Observational tests of the magnetar model are outlined, along with current ideas about the trigger of SGR outbursts, new evidence for the trapped fireball model, and the influence of QED processes on X-ray spectra and lightcurves. A critical examination is made of coherent radio emission from bursting strong-field neutron stars. I conclude with an overview of the genetic connection between neutron star magnetism and the violent fluid motions in a collapsing supernova core.

Christopher Thompson

2000-10-02T23:59:59.000Z

329

X-ray afterglows from gamma-ray bursts  

E-Print Network (OSTI)

We consider possible interpretations of the recently detected X- ray afterglow from the gamma-ray burst source GRB 970228. Cosmological and Galactic models of gamma-ray bursts predict different flux and spectral evolution of X-ray afterglows. We show that models based on adiabatic expansion of relativistic forward shocks require very efficient particle energization or post-burst re-acceleration during the expansion. Cooling neutron star models predict a very distinctive spectral and flux evolution that can be tested in current X-ray data.

M. Tavani

1997-03-24T23:59:59.000Z

330

Ten years of Vela x-ray observations  

SciTech Connect

The Vela spacecraft, particularly Vela 5B, produced all-sky X-ray data of unprecedented length and completeness. The data led to the discovery of X-ray bursts and numerous transient outbursts. Recent re-analysis has put the data in the form of 10-day skymaps covering a 7-year period, which have led to the discovery or confirmation of a number of long-term periodicities, and have made possible a time-lapse movie of the X-ray sky.

Terrell, J.; Priedhorsky, W.C.

1983-01-01T23:59:59.000Z

331

Sixth International Conference on X-ray Microscopy  

SciTech Connect

More than 180 participants from around the world crowded the Clark Kerr Campus of the University of California, Berkeley, from August 1-6, 1999 for the Sixth International Conference on X-Ray Microscopy (XRM99). Held every three years since 1983, the XRM conferences have become the primary international forum for the presentation and discussion of advances in high-spatial-resolution x-ray imaging and applications (including the use of x-ray spectroscopic and analytical techniques) in biological and medical sciences, environmental and soil sciences, and materials and surface sciences.

Robinson, Arthur L.

1999-08-23T23:59:59.000Z

332

USING THE X-RAY EMISSION LINES OF SEYFERT 2 AGN TO MEASURE ABUNDANCE RATIOS  

E-Print Network (OSTI)

We measure the metal abundance ratios in the X-ray photoionized gas located near the narrow line region of a sample of Seyfert 2 AGN. The high-resolution X-ray spectra observed with the Chandra high- and low-energy transmission grating spectrometers are compared with models of the resonant scattering and recombination emission from a plasma in thermal balance, and with multiple temperature zones. The abundance ratios in the sample are close to the Solar values, with slight over-abundances of N in NGC 1068, and of Ne in NGC 4151. Our X-ray spectral models use fewer degrees of freedom than previous works. Motivation. Our goal is to use X-ray abundance measurements to cross-calibrate with the optical spectra of quasars. These optical spectra are used to measure the star formation history of the early Universe. 1 To Determine the Abundance Ratios, we fit the Seyfert 2 spectra with models of photoionized plasmas, and then search for deviations in the data from Solar abundances, as shown in Fig. 1. The fluxes of radiative recombination continuum (RRC) features and the radiative recombination (RR) forbidden lines depend little on radiation transfer effects, so they are the most reliable abundance indicators. At low continuum optical depths, the recombination emission flux scales linearly with abundances. Our model allows us to fit the RRC and RR fluxes by accounting for the broad ionization distribution in the plasma. X-ray Emission Line Model. We model a photoionized plasma in ionization equilibrium and thermal balance with a grid of zones, each with ionization parameter log ? = 1.0, 1.5,...4.5 (in c.g.s. units). The XSTAR plasma code yields the charge state distribution of each zone. 2 In order to calculate the recombination emission, we use the photoelectric cross sections

Mario A. Jimenez-garate; Toan Khu

2004-01-01T23:59:59.000Z

333

Non-Thermal X-ray Properties of Rotation Powered Pulsars and Their Wind Nebulae  

E-Print Network (OSTI)

We present a statistical study of the non-thermal X-ray emission of 27 young rotation powered pulsars (RPPs) and 24 pulsar wind nebulae (PWNe) by using the Chandra and the XMM-Newton observations, which with the high spatial resolutions enable us to spatially resolve pulsars from their surrounding PWNe. We obtain the X-ray luminosities and spectra separately for RPPs and PWNe, and then investigate their distribution and relation to each other as well as the relation with the pulsar rotational parameters. In the pair-correlation analysis we find that: (1) the X-ray (2-10 keV) luminosities of both pulsar and PWN (L_{psr} and L_{pwn}) display a strong correlation with pulsar spin down power Edot and characteristic age, and the scalings resulting from a simple linear fit to the data are L_{psr} \\propto Edot^{0.92 \\pm 0.04} and L_{pwn} \\propto Edot^{1.45 \\pm 0.08} (68% confidence level), respectively, however, both the fits are not statistically acceptable; (2) L_{psr} also shows a possible weak correlation with pulsar period P and period derivative Pdot, whereas L_{pwn} manifests a similar weak correlation with Pdot only; (3) The PWN photon index Gamma_{pwn} is positively correlated with L_{pwn} and L_{pwn}/Edot. We also found that the PWN X-ray luminosity is typically 1 to 10 times larger than that from the underlying pulsar, and the PWN photon indices span a range of ~1.5 to ~2. The statistic study of PWN spectral properties supports the particle wind model in which the X-ray emitting electrons are accelerated by the termination shock of the wind.

Xiang-Hua Li; Fang-Jun Lu; Zhuo Li

2007-07-29T23:59:59.000Z

334

X-RAY STRIPES IN TYCHO'S SUPERNOVA REMNANT: SYNCHROTRON FOOTPRINTS OF A NONLINEAR COSMIC-RAY-DRIVEN INSTABILITY  

Science Conference Proceedings (OSTI)

High-resolution Chandra observations of Tycho's supernova remnant (SNR) have revealed several sets of quasi-steady, high-emissivity, nearly parallel X-ray stripes in some localized regions of the SNR. These stripes are most likely the result of cosmic-ray (CR) generated magnetic turbulence at the SNR blast wave. However, for the amazingly regular pattern of these stripes to appear, simultaneous action of a number of shock-plasma phenomena is required, which is not predicted by most models of magnetic field amplification. A consistent explanation of these stripes yields information on the complex nonlinear plasma processes connecting efficient CR acceleration and magnetic field fluctuations in strong collisionless shocks. The nonlinear diffusive shock acceleration (NL-DSA) model described here, which includes magnetic field amplification from a CR-current-driven instability, does predict stripes consistent with the synchrotron observations of Tycho's SNR. We argue that the local ambient mean magnetic field geometry determines the orientation of the stripes and therefore it can be reconstructed with the high-resolution X-ray imaging. The estimated maximum energy of the CR protons responsible for the stripes is {approx}10{sup 15} eV. Furthermore, the model predicts that a specific X-ray polarization pattern, with a polarized fraction {approx}50%, accompanies the stripes, which can be tested with future X-ray polarimeter missions.

Bykov, Andrei M.; Osipov, Sergei M.; Uvarov, Yury A. [Ioffe Physical-Technical Institute, St. Petersburg (Russian Federation); Ellison, Donald C. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Pavlov, George G., E-mail: byk@astro.ioffe.ru, E-mail: osm@astro.ioffe.ru, E-mail: uv@astro.ioffe.ru, E-mail: don_ellison@ncsu.edu, E-mail: pavlov@astro.psu.edu [525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States)

2011-07-10T23:59:59.000Z

335

Active pixel sensors for X-ray astronomy  

E-Print Network (OSTI)

An active pixel sensor array, APS-1, has been fabricated for the purpose of scientific x-ray detection. This thesis presents the results of testing the device. Alternate design architectures are explored. Recommendations ...

Cohen, Matthew (Matthew L.)

2005-01-01T23:59:59.000Z

336

Definition: Portable X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Portable X-Ray Diffraction (XRD) Jump to: navigation, search 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, which has traditionally been used in geology, environmental science, material science, and engineering to rapidly identify unknown crystalline substances. Portable XRD analysis allows for simpler sample preparation, faster analytical times than traditional methods (less than 2 minutes), and can be performed at the sampling site in the field. A pure, finely ground

337

SLAC National Accelerator Laboratory - Fifth X-ray Instrument...  

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

and more.) The technique has been used for years to probe materials with visible-light lasers, and more recently with X-ray light from synchrotrons. But the LCLS is the first...

338

SLAC National Accelerator Laboratory - X-ray Vision Exposes Aerosol...  

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

up exciting possibilities in the study of aerosol dynamics using highly focused X-ray lasers, such as SLAC's Linac Coherent Light Source (LCLS). "Our study shows that LCLS can...

339

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

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

Ocko, B.M., Wen, K., Maoz, R., Cohen, H., and Sagiv, J. Non-destructive chemical modification of a preassembled silane multilayer: structural study by combined FTIR, x-ray...

340

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

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

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...

342

Radiological Safety Training for Radiation-Producing (X-Ray)...  

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

for General Radiation Safety Installations Using Non-Medical X-Ray and Sealed Gamma-Ray Sources, Energies up to 10 MEV, ANSI Standard N43.3, American National Standards...

343

Low Dose Radiation Research Program: Comparison of Soft X Rays...  

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

Comparison of Soft X-Rays and Ions Irradiation in a Model of V79 Mammalian Cell Authors: B. Ginovska, J.H. Miller, D. J. Lynch and W. E. Wilson Institutions: School of Electrical...

344

SLAC National Accelerator Laboratory - X-rays Reveal How Soil...  

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

2012 Menlo Park, Calif. - Researchers working at the U.S. Department of Energy's (DOE) SLAC National Accelerator Laboratory have used powerful X-rays to help decipher how certain...

345

Argonne TDC: Large Area CCD X-Ray Detector  

Large-Area CCD X-Ray Detector Opening Up New Horizons in the Study of Cellular and Metabolic Processes, Genetics, and Drug Development 2000 R&D 100 Award Winner!

346

Vitreous carbon mask substrate for X-ray lithography  

DOE Patents (OSTI)

The present invention is directed to the use of vitreous carbon as a substrate material for providing masks for X-ray lithography. The new substrate also enables a small thickness of the mask absorber used to pattern the resist, and this enables improved mask accuracy. An alternative embodiment comprised the use of vitreous carbon as a LIGA substrate wherein the VC wafer blank is etched in a reactive ion plasma after which an X-ray resist is bonded. This surface treatment provides a surface enabling good adhesion of the X-ray photoresist and subsequent nucleation and adhesion of the electrodeposited metal for LIGA mold-making while the VC substrate practically eliminates secondary radiation effects that lead to delamination of the X-ray resist form the substrate, the loss of isolated resist features, and the formation of a resist layer adjacent to the substrate that is insoluble in the developer.

Aigeldinger, Georg (Livermore, CA); Skala, Dawn M. (Fremont, CA); Griffiths, Stewart K. (Livermore, CA); Talin, Albert Alec (Livermore, CA); Losey, Matthew W. (Livermore, CA); Yang, Chu-Yeu Peter (Dublin, CA)

2009-10-27T23:59:59.000Z

347

SLAC National Accelerator Laboratory - X-ray Laser Takes Aim...  

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

Laser Takes Aim at Cosmic Mystery December 12, 2012 Menlo Park, Calif. - Scientists have used powerful X-rays from the Linac Coherent Light Source (LCLS) at the U.S. Department of...

348

SLAC National Accelerator Laboratory - X-ray Laser Sees Photosynthesis...  

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

new window on the way plants generate the oxygen we breathe, researchers used an X-ray laser at the Department of Energy's (DOE) SLAC National Accelerator Laboratory to...

349

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...

350

Material Characterization with X-ray and Optical Techniques I  

Science Conference Proceedings (OSTI)

In Situ X-ray Nanocharacterization of Defects in Solar Cells: Mariana Bertoni1; ... a strong modeling tool for predicting and optimizing solar cell efficiency. ... levels (11 steps up to 55%) in order to understand the sequential damage process.

351

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

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

D.F. Inelastic x-ray scattering investigations of lattice dynamics in SmFeAsO1-xFy superconductors. Proceedings of The 9th International Conference on Spectroscopies in Novel...

352

SLAC National Accelerator Laboratory - X-rays Capture Electron...  

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

X-rays Capture Electron 'Dance' By Glenn Roberts Jr. January 30, 2013 The way electrons move within and between molecules, transferring energy as they go, plays an important role...

353

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 Print Schemes that use one light pulse to manipulate interactions of another with matter are well developed in the...

354

High performance x-ray anti-scatter grid  

DOE Patents (OSTI)

Disclosed are an x-ray anti-scatter grid for x-ray imaging, particularly for screening mammography, and method for fabricating same, x-rays incident along a direct path pass through a grid composed of a plurality of parallel or crossed openings, microchannels, grooves, or slots etched in a substrate, such as silicon, having the walls of the microchannels or slots coated with a high opacity material, such as gold, while x-rays incident at angels with respect to the slots of the grid, arising from scatter, are blocked. The thickness of the substrate is dependent on the specific application of the grid, whereby a substrate of the grid for mammography would be thinner than one for chest radiology. Instead of coating the walls of the slots, such could be filed with an appropriate liquid, such as mercury. 4 Figs.

Logan, C.M.

1995-05-23T23:59:59.000Z

355

High performance x-ray anti-scatter grid  

DOE Patents (OSTI)

An x-ray anti-scatter grid for x-ray imaging, particularly for screening mammography, and method for fabricating same, x-rays incident along a direct path pass through a grid composed of a plurality of parallel or crossed openings, microchannels, grooves, or slots etched in a substrate, such as silicon, having the walls of the microchannels or slots coated with a high opacity material, such as gold, while x-rays incident at angels with respect to the slots of the grid, arising from scatter, are blocked. The thickness of the substrate is dependent on the specific application of the grid, whereby a substrate of the grid for mammography would be thinner than one for chest radiology. Instead of coating the walls of the slots, such could be filed with an appropriate liquid, such as mercury.

Logan, Clinton M. (Pleasanton, CA)

1995-01-01T23:59:59.000Z

356

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

357

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

358

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

359

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...

360

SLAC National Accelerator Laboratory - X-ray Laser Research Ranks...  

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

selected science "Breakthrough of the Year": the discovery of what appears to be the Higgs boson. Scientists aimed the Linac Coherent Light Source X-ray laser at thousands of tiny...

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

Calibration of High-Resolution X-Ray Tomography With ...  

Science Conference Proceedings (OSTI)

... The x-ray attenuation of the sample at this energy was close to the ... J. Coal Geol. ... G. Xu, DE Eastman, I. McNulty, SP Frigo, Y. Wang, CC Retsch, IC ...

2001-04-11T23:59:59.000Z

362

Photon Sciences | Beamlines | SRX: Submicron Resolution X-ray Spectroscopy  

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

SRX: Submicron Resolution X-ray Spectroscopy SRX: Submicron Resolution X-ray Spectroscopy Poster | Fact Sheet | Preliminary Design Report Scientific Scope Scientific communities such as environmental sciences, life sciences, and material sciences have identified the need to develop analytical resources to advance the understanding of complex natural and engineered systems that are heterogeneous on the micron to nanometer scale. These needs for high intensity x-ray nanoprobes resulted in the commitment of the NSLS-II Project to build the Submicron Resolution X-ray (SRX) Spectroscopy beamline showing a unique combination of high spectral resolution over a very broad energy range and very high beam intensity in a sub-micrometer spot. NSLS-II will provide one of the best sources in the world for such an instrument.

363

Correspondence between Electro-Magnetic Field and other Dark Energies in Non-linear Electrodynamics  

E-Print Network (OSTI)

In this work, we have considered the flat FRW model of the universe filled with electro-magnetic field. First, the Maxwell's electro-magnetic field in linear form has been discussed and after that the modified Lagrangian in non-linear form for accelerated universe has been considered. The corresponding energy density and pressure for non-linear electro-magnetic field have been calculated. We have found the condition such that the electro-magnetic field generates dark energy. The correspondence between the electro-magnetic field and the other dark energy candidates namely tachyonic field, DBI-essence, Chaplygin gas, hessence dark energy, k-essenece and dilaton dark energy have been investigated. We have also reconstructed the potential functions and the scalar fields in this scenario.

Maity, Sayani; Debnath, Ujjal

2011-01-01T23:59:59.000Z

364

Correspondence between Electro-Magnetic Field and other Dark Energies in Non-linear Electrodynamics  

E-Print Network (OSTI)

In this work, we have considered the flat FRW model of the universe filled with electro-magnetic field. First, the Maxwell's electro-magnetic field in linear form has been discussed and after that the modified Lagrangian in non-linear form for accelerated universe has been considered. The corresponding energy density and pressure for non-linear electro-magnetic field have been calculated. We have found the condition such that the electro-magnetic field generates dark energy. The correspondence between the electro-magnetic field and the other dark energy candidates namely tachyonic field, DBI-essence, Chaplygin gas, hessence dark energy, k-essenece and dilaton dark energy have been investigated. We have also reconstructed the potential functions and the scalar fields in this scenario.

Sayani Maity; Shuvendu Chakraborty; Ujjal Debnath

2011-04-12T23:59:59.000Z

365

Three-dimensional MHD simulations of X-ray emitting subcluster plasmas in cluster of galaxies  

E-Print Network (OSTI)

Recent high resolution observations by the {\\it Chandra} X-ray satellite revealed various substructures in hot X-ray emitting plasmas in cluster of galaxies. For example, {\\it Chandra} revealed the existence of sharp discontinuities in the surface brightness at the leading edge of subclusters in merging clusters (e.g., Abell 3667), where the temperature drops sharply across the fronts. These sharp edges are called cold fronts. We present results of three-dimensional (3D) magnetohydrodynamic simulations of the interaction between a dense subcluster plasma and ambient magnetized intracluster medium. Anisotropic heat conduction along magnetic field lines is included. At the initial state, magnetic fields are assumed to be uniform and transverse to the motion of the dense subcluster. Since magnetic fields ahead of the subcluster slip toward the third direction in the 3D case, the strength of magnetic fields in this region can be reduced compared to that in the 2D case. Nevertheless, a cold front can be maintained because the magnetic field lines wrapping around the forehead of the subcluster suppress the heat conduction across them. On the other hand, when the magnetic field is absent, a cold front cannot be maintained because isotropic heat conduction from the hot ambient plasma rapidly heats the cold subcluster plasma.

Naoki Asai; Naoya Fukuda; Ryoji Matsumoto

2005-04-09T23:59:59.000Z

366

Scanning Transmission X-ray Microscopy: Applications in Atmospheric Aerosol Research  

E-Print Network (OSTI)

G. R. et al. Scanning transmission X-ray microscopy: A newwith the scanning transmission X-ray microscope at BESSY II.T. et al. Scanning transmission X-ray microscopy imaging of

Moffet, Ryan C.

2011-01-01T23:59:59.000Z

367

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...

368

X-ray Science Division: Mission and Goals | Advanced Photon Source  

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

X-ray Science Division: Mission and Goals The mission of the X-ray Science Division (XSD) is to enable and perform world class research using x-rays. This mission is accomplished...

369

X-ray streak and framing camera techniques  

SciTech Connect

This paper reviews recent developments and applications of ultrafast diagnostic techniques for x-ray measurements. These techniques, based on applications of image converter devices, are already capable of significantly important resolution capabilities. Techniques capable of time resolution in the sub-nanosecond regime are being considered. Mechanical cameras are excluded from considerations as are devices using phosphors or fluors as x-ray converters.

Coleman, L.W.; Attwood, D.T.

1975-12-23T23:59:59.000Z

370

The complex soft X-ray spectrum of NGC 4151  

E-Print Network (OSTI)

We present a detailed analysis of the complex soft X-ray spectrum of NGC 4151 measured by the RGS instruments aboard XMM-Newton. The XMM-Newton RGS spectra demonstrate that the soft X-ray emission is extremely rich in X-ray emission lines and radiative recombination continua (RRC), with no clear evidence for any underlying continuum emission. Line emission, and the associated RRC, are clearly detected from hydrogen-like and helium-like ionization states of neon, oxygen, nitrogen and carbon. The measured lines are blueshifted with a velocity of between ~100-1000 km/s, with respect to the systemic velocity of NGC 4151, approximately consistent with the outflow velocities of the absorption lines observed in the UV, suggestive of an origin for the UV and soft X-ray emission in the same material. Plasma diagnostics imply a range of electron temperatures of ~1-5x10^4 K and electron densities of between 10^8-10^10 cm^-3. The soft X-ray spectrum of NGC 4151 is extremely similar to that of NGC 1068, suggesting that the soft X-ray excesses observed in many Seyfert galaxies may be composed of similar emission features. Modelling the RGS spectra in terms of emission from photoionized and photoexcited gas in an ionization cone reproduces all of the hydrogen-like and helium-like emission features observed in the soft X-ray spectrum of NGC 4151 in detail and confirms the correspondence between the soft X-ray emission in NGC 4151 and NGC 1068.

N. J. Schurch; R. S. Warwick; R. E. Griffiths; S. M. Kahn

2004-01-26T23:59:59.000Z

371

Apparatus for obtaining an X-ray image  

DOE Patents (OSTI)

A computed tomography apparatus in which a fan-shaped X-ray beam is caused to pass through a section of an object, enabling absorption detection on the opposite side of the object by a detector comprising a plurality of discrete detector elements. An electron beam generating the X-ray beam by impacting upon a target is caused to rotate over the target.

Watanabe, Eiji (Tokyo, JP)

1979-01-01T23:59:59.000Z

372

Kinoform optics applied to X-ray photon correlation specroscopy  

Science Conference Proceedings (OSTI)

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

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

2010-03-01T23:59:59.000Z

373

Flat Quartz-Crystal X-ray Spectrometer for Nuclear Forensics Applications  

E-Print Network (OSTI)

The ability to quickly and accurately quantify the plutonium (Pu) content in pressurized water reactor (PWR) spent nuclear fuel (SNF) is critical for nuclear forensics purposes. One non-destructive assay (NDA) technique being investigated to detect bulk Pu in SNF is measuring the self-induced x-ray fluorescence (XRF). Previous XRF measurements of Three Mile Island (TMI) PWR SNF taken in July 2008 and January 2009 at Oak Ridge National Laboratory (ORNL) successfully illustrated the ability to detect the 103.7 keV x ray from Pu using a planar high-purity germanium (HPGe) detector. This allows for a direct measurement of Pu in SNF. Additional gamma ray and XRF measurements were performed on TMI SNF at ORNL in October 2011 to measure the signal-to-noise ratio for the 103.7 keV peak. Previous work had shown that the Pu/U peak ratio was directly proportional to the Pu/U content and increased linearly with burnup. However, the underlying Compton background significantly reduced the signal-to-noise ratio for the x-ray peaks of interest thereby requiring a prolonged count time. Comprehensive SNF simulations by Stafford et al showed the contributions to the Compton continuum were due to high-energy gamma rays scattering in the fuel, shipping tube, cladding, collimator and detector1. The background radiation was primarily due to the incoherent scattering of the 137Cs 661.7 keV gamma. In this work methods to reduce the Compton background and thereby increase the signal-to-noise ratio were investigated. To reduce the debilitating effects of the Compton background, a crystal x-ray spectrometer system was designed. This wavelength-dispersive spectroscopy technique isolated the Pu and U x rays according to Bragg's law by x-ray diffraction through a crystal structure. The higher energy background radiation was blocked from reaching the detector using a customized collimator and shielding system. A flat quartz-crystal x-ray spectrometer system was designed specifically to fit the constraints and requirements of detecting XRF from SNF. Simulations were performed to design and optimize the collimator design and to quantify the improved signal-to-noise ratio of the Pu and U x-ray peaks. The proposed crystal spectrometer system successfully diffracted the photon energies of interest while blocking the high-energy radiation from reaching the detector and contributing to background counts. The spectrometer system provided a higher signal-to-noise ratio and lower percent error for the XRF peaks of interest from Pu and U. Using the flat quartz-crystal x-ray spectrometer and customized collimation system, the Monte Carlo N-Particle (MCNP) simulations showed the 103.7 keV Pu x-ray peak signal-to-noise ratio improved by a factor of 13 and decreased the percent error by a factor of 3.3.

Goodsell, Alison

2012-08-01T23:59:59.000Z

374

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

375

Involvement of recombination in x-ray mutagenesis of human cells  

SciTech Connect

Closely related human lymphoblastoid cell lines derived from WI-L2 differ greatly in their responses to X-irradiation. Compared with TK6 (ATCC CRL 8015), WI-L2-NS (ATCC CRL 8155) has an enhanced X-ray survival. The induction of mutation by X-rays is also markedly different. The hemizygous hprt locus is slightly more mutable in WI-L2-NS than in TK6, and the dose response fits best to a linear-quadratic curve rather than the linear fit of TK6X-ray induced mutation at the autosomal tk locus in heterozygotes derived from WI-L2-NS is 20-50 fold higher than in heterozygotes derived from TK6. A larger proportion of WI-L2-NS mutants had lost heterozygosity compared with mutants of TK6. , Fluorescence in situ hybridization indicated that loss of heterozygosity was due almost uniformly to deletion of an allele in mutants of TK6, and to recombination or gene conversion in mutants of WI-L2-NS. These results indicate that recombinational repair contributes to both cell survival and mutation following exposure to ionizing radiation.

Amundson, S.A. (Los Alamos National Lab., NM (United States)); Xia, F.; Liber, H.L. (Harvard School of Public Health, Boston, MA (United States))

1993-01-01T23:59:59.000Z

376

Involvement of recombination in x-ray mutagenesis of human cells  

SciTech Connect

Closely related human lymphoblastoid cell lines derived from WI-L2 differ greatly in their responses to X-irradiation. Compared with TK6 (ATCC CRL 8015), WI-L2-NS (ATCC CRL 8155) has an enhanced X-ray survival. The induction of mutation by X-rays is also markedly different. The hemizygous hprt locus is slightly more mutable in WI-L2-NS than in TK6, and the dose response fits best to a linear-quadratic curve rather than the linear fit of TK6X-ray induced mutation at the autosomal tk locus in heterozygotes derived from WI-L2-NS is 20-50 fold higher than in heterozygotes derived from TK6. A larger proportion of WI-L2-NS mutants had lost heterozygosity compared with mutants of TK6. , Fluorescence in situ hybridization indicated that loss of heterozygosity was due almost uniformly to deletion of an allele in mutants of TK6, and to recombination or gene conversion in mutants of WI-L2-NS. These results indicate that recombinational repair contributes to both cell survival and mutation following exposure to ionizing radiation.

Amundson, S.A. [Los Alamos National Lab., NM (United States); Xia, F.; Liber, H.L. [Harvard School of Public Health, Boston, MA (United States)

1993-06-01T23:59:59.000Z

377

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 Print Using Light to Control How X Rays Interact with Matter Print Schemes that use one light pulse to manipulate interactions of another with matter are well developed in the visible-light regime where an optical control pulse influences how an optical probe pulse interacts with a medium. This approach has opened new research directions in fields like quantum computing and nonlinear optics, while also spawning entirely new research areas, such as electromagnetically induced transparency and slow light. However, it has been unclear whether similar optical control schemes could be used to modify how x rays interact with matter. In a dramatic breakthrough demonstration at the ALS, a Berkeley Lab-Argonne National Laboratory group has now used powerful visible-light lasers to render a nominally opaque material transparent to x rays. While x-ray transparency will have immediate applications at x-ray light sources, the important result is that the findings lay a foundation for a broader spectrum of applications.

378

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 Print Using Light to Control How X Rays Interact with Matter Print Schemes that use one light pulse to manipulate interactions of another with matter are well developed in the visible-light regime where an optical control pulse influences how an optical probe pulse interacts with a medium. This approach has opened new research directions in fields like quantum computing and nonlinear optics, while also spawning entirely new research areas, such as electromagnetically induced transparency and slow light. However, it has been unclear whether similar optical control schemes could be used to modify how x rays interact with matter. In a dramatic breakthrough demonstration at the ALS, a Berkeley Lab-Argonne National Laboratory group has now used powerful visible-light lasers to render a nominally opaque material transparent to x rays. While x-ray transparency will have immediate applications at x-ray light sources, the important result is that the findings lay a foundation for a broader spectrum of applications.

379

Using Light to Control How X Rays Interact with Matter  

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

Using Light to Control How X 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 pulse to manipulate interactions of another with matter are well developed in the visible-light regime where an optical control pulse influences how an optical probe pulse interacts with a medium. This approach has opened new research directions in fields like quantum computing and nonlinear optics, while also spawning entirely new research areas, such as electromagnetically induced transparency and slow light. However, it has been unclear whether similar optical control schemes could be used to modify how x rays interact with matter. In a dramatic breakthrough demonstration at the ALS, a Berkeley Lab-Argonne National Laboratory group has now used powerful visible-light lasers to render a nominally opaque material transparent to x rays. While x-ray transparency will have immediate applications at x-ray light sources, the important result is that the findings lay a foundation for a broader spectrum of applications.

380

X-ray emission from colliding laser plasmas  

SciTech Connect

Colliding Au, CD and Ti-Cr plasmas have been generated by illuminating two opposing foils each with a {approximately} 100J, 0.5 nsec, 2{omega} Nd-glass laser beam from the Trident laser facility at Los Alamos. The plasmas are being used to study plasma interactions which span the parameter regime from interpenetrating to collisional stagnation. X-ray emission during the laser target interaction and the subsequent collision is used to diagnose the initial plasma conditions and the colliding plasma properties. X-ray instrumentation consists of a 100 ps gated x-ray pinhole imager, a time-integratcd bremsstrahlung x-ray spectrograph and a gated x-ray spectrograph used to record isoelectronic spectra from the Ti-Cr plasmas. The imager has obtained multi-frame images of the collision and therefore, a measure of the stagnation length which is a function of the ion charge state and density and a strong function of the electron temperature. Other instrumentation includes a Thomson scattering spectrometer with probe beam, neutron detectors used to monitor the CD coated foil collisions and an ion spectrometer. We will describe the current status of the experiments and current results with emphasis on the x-ray emission diagnostics. We will also briefly describe the modeling using Lasnex and ISIS, a particle-in-cell code with massless fluid electrons and inter particle (classical) collisions.

Wilke, M.; Obst, A.W.; Winske, D. [and others

1995-09-01T23:59:59.000Z

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381

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

382

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

383

Dilation x-ray imager a new/faster gated x-ray imager for the NIF  

SciTech Connect

As the yield on implosion shots increases it is expected that the peak x-ray emission reduces to a duration with a FWHM as short as 20 ps for {approx}7 Multiplication-Sign 10{sup 18} neutron yield. However, the temporal resolution of currently used gated x-ray imagers on the NIF is 40-100 ps. We discuss the benefits of the higher temporal resolution for the NIF and present performance measurements for dilation x-ray imager, which utilizes pulse-dilation technology [T. J. Hilsabeck et al., Rev. Sci. Instrum. 81, 10E317 (2010)] to achieve x-ray imaging with temporal gate times below 10 ps. The measurements were conducted using the COMET laser, which is part of the Jupiter Laser Facility at the Lawrence Livermore National Laboratory.

Nagel, S. R.; Bell, P. M.; Bradley, D. K.; Ayers, M. J.; Barrios, M. A.; Felker, B.; Smith, R. F.; Collins, G. W.; Jones, O. S.; Piston, K.; Raman, K. S. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Hilsabeck, T. J.; Kilkenny, J. D.; Chung, T.; Sammuli, B. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Hares, J. D.; Dymoke-Bradshaw, A. K. L. [Kentech Instruments Ltd., Wallingford, Oxfordshire OX10 (United Kingdom)

2012-10-15T23:59:59.000Z

384

EVIDENCE FOR POLAR X-RAY JETS AS SOURCES OF MICROSTREAM PEAKS IN THE SOLAR WIND  

Science Conference Proceedings (OSTI)

It is proposed that the interplanetary manifestations of X-ray jets observed in solar polar coronal holes during periods of low solar activity are the peaks of the so-called microstreams observed in the fast polar solar wind. These microstreams exhibit velocity fluctuations of {+-}35 km s{sup -1}, higher kinetic temperatures, slightly higher proton fluxes, and slightly higher abundances of the low-first-ionization-potential element iron relative to oxygen ions than the average polar wind. Those properties can all be explained if the fast microstreams result from the magnetic reconnection of bright-point loops, which leads to X-ray jets which, in turn, result in solar polar plumes. Because most of the microstream peaks are bounded by discontinuities of solar origin, jets are favored over plumes for the majority of the microstream peaks.

Neugebauer, Marcia, E-mail: mneugeb@lpl.arizona.edu [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

2012-05-01T23:59:59.000Z

385

A linear helicon plasma device with controllable magnetic field gradient  

Science Conference Proceedings (OSTI)

Current free double layers (CFDLs) are localized potential structures having spatial dimensions - Debye lengths and potential drops of more than local electron temperature across them. CFDLs do not need a current for them to be sustained and hence they differ from the current driven double layers. Helicon antenna produced plasmas in an expanded chamber along with an expanding magnetic field have shown the existence of CFDL near the expansion region. A helicon plasma device has been designed, fabricated, and installed in the Institute for Plasma Research, India to study the role of maximum magnetic field gradient as well as its location with respect to the geometrical expansion region of the chamber in CFDL formation. The special feature of this machine consisting of two chambers of different radii is its capability of producing different magnetic field gradients near the physical boundary between the two chambers either by changing current in one particular coil in the direction opposite to that in other coils and/or by varying the position of this particular coil. Although, the machine is primarily designed for CFDL experiments, it is also capable of carrying out many basic plasma physics experiments such as wave propagation, wave coupling, and plasma instabilities in a varying magnetic field topology. In this paper, we will present the details of the machine construction, its specialties, and some preliminary results about the production and characterization of helicon plasma in this machine.

Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

2012-06-15T23:59:59.000Z

386

Understanding Water Uptake and Transport in Nafion Using X-ray...  

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

Understanding Water Uptake and Transport in Nafion Using X-ray Microtomography Title Understanding Water Uptake and Transport in Nafion Using X-ray Microtomography Publication Type...

387

Commissioning of a Soft X-ray Beamline PF-BL-16A with a Variable-Included-Angle Varied-Line-Spacing Grating Monochromator  

Science Conference Proceedings (OSTI)

The design and commissioning of a new soft X-ray beamline, BL-16A, at the Photon Factory is presented. The beamline consists of a pre-focusing mirror, an entrance slit, a variable-included-angle varied-line-spacing plane grating monochromator, and a post-focusing system as usual, and provides circularly and linearly polarized soft X rays in the energy range 200-1500 eV with an APPLE-II type undulator. The commissioning procedure for the beamline optics is described in detail, especially the check of the focal position for the zero-th order and diffracted X rays.

Amemiya, Kenta; Toyoshima, Akio; Kikuchi, Takashi; Kosuge, Takashi; Nigorikawa, Kazuyuki; Sumii, Ryohei; Ito, Kenji [Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

2010-06-23T23:59:59.000Z

388

The X-ray afterglow flat segment in short GRB 051221A: Energy injection from a millisecond magnetar?  

E-Print Network (OSTI)

The flat segment lasting $\\sim 10^4$ seconds in the X-ray afterglow of GRB051221A represents the first clear case of strong energy injection in the external shock of a short GRB afterglow. In this work, we show that a millisecond pulsar with dipole magnetic field $\\sim 10^{14}$ Gauss could well account for that energy injection. The good quality X-ray flat segment thus suggests that the central engine of this short burst may be a millisecond magnetar.

Yizhong Fan; Dong Xu

2006-05-18T23:59:59.000Z

389

Enhanced inner-shell x-ray emission by femtosecond-laser irradiation of solid cone targets  

Science Conference Proceedings (OSTI)

The possibility of enhancing inner-shell x-ray emission, especially K{alpha} emission, by femtosecond-laser irradiation of solid cones instead of foils was investigated theoretically. In a model for hot electron (HE) transport and K{alpha} x-ray generation, K{alpha} emission from laser-irradiated solid cones and foils is investigated. As a complementarity to the model, the contributions from electric and magnetic fields generated by the HE current in solid cones and foils are discussed. The results indicate that the efficiency of HE energy conversion to K{alpha} photons is improved and the optimum HE temperature is increased.

Li Xiaoya; Zhu Wenjun; Ye Yan; Li Jun; Yu Yong [National Key Laboratory of Shock Wave and Detonation Physics, Mianyang, 621900 Sichuan (China); Wang Jiaxiang [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China)

2011-04-15T23:59:59.000Z

390

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

391

Water destruction by X-rays in young stellar objects  

E-Print Network (OSTI)

We study the H2O chemistry in star-forming environments under the influence of a central X-ray source and a central far ultraviolet (FUV) radiation field. The gas-phase water chemistry is modeled as a function of time, hydrogen density and X-ray flux. To cover a wide range of physical environments, densities between n_H = 10^4-10^9 cm^-3 and temperatures between T = 10-1000 K are studied. Three different regimes are found: For T water abundance is of order 10^-7-10^-6 and can be somewhat enhanced or reduced due to X-rays, depending on time and density. For 100 K 10^-3 ergs s-1 cm^-2 (t = 10^4 yrs) and for F_X > 10^-4 ergs s^-1 cm^-2 (t = 10^5 yrs). At higher temperatures (T > 250 K) and hydrogen densities, water can persist with x(H2O) ~ 10^-4 even for high X-ray fluxes. The X-ray and FUV models are applied to envelopes around low-mass Class 0 and I young stellar objects (YSOs). Water is destroyed in both Class 0 and I envelopes on relatively short timescales (t ~ 5000 yrs) for realistic X-ray fluxes, although the effect is less prominent in Class 0 envelopes due to the higher X-ray absorbing densities there. FUV photons from the central source are not effective in destroying water. The average water abundance in Class I sources for L_X > 10^27 ergs s^-1 is predicted to be x(H2O) < 10^-6.

P. Stauber; J. K. Jorgensen; E. F. van Dishoeck; S. D. Doty; A. O. Benz

2006-02-06T23:59:59.000Z

392

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

393

Proposed Laser-driven, Dielectric Microstructure Few-cm Long Undulator for Attosecond Coherent X-rays  

SciTech Connect

This article presents the concept of an all-dielectric laser-driven undulator for the generation of coherent X-rays. The proposed laser-driven undulator is expected to produce internal deflection forces equivalent to a several-Tesla magnetic field acting on a speed-of-light particle. The key idea for this laser-driven undulator is its ability to provide phase synchronicity between the deflection force and the electron beam for a distance that is much greater than the laser wavelength. The potential advantage of this undulator is illustrated with a possible design example that assumes a small laser accelerator which delivers a 2 GeV, 1 pC, 1 kHz electron bunch train to a 10 cm long, 1/2 mm period laser-driven undulator. Such an undulator could produce coherent X-ray pulses with {approx}10{sup 9} photons of 64 keV energy. The numerical modeling for the expected X-ray pulse shape was performed with GENESIS, which predicts X-ray pulse durations in the few-attosecond range. Possible applications for nonlinear electromagnetic effects from these X-ray pulses are briefly discussed.

Plettner, T; Byer, R.L.; /Stanford U., Ginzton Lab.

2011-09-16T23:59:59.000Z

394

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

395

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

396

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

397

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

398

Ultrafast x-ray diagnostics for laser fusion experiments  

SciTech Connect

Temporally, spectrally, and spatially resolved x-ray emission diagnostics are important tools in the study of the heating and compression of laser fusion targets by sub-nanosecond laser pulses. The use of the Livermore 15 psec resolution x-ray streak camera to make such measurements is reviewed. Temporal histories of spectrally resolved x-ray emission in the 1 to 10 keV range have been obtained. These data have served to further define the x-ray streak camera as a quantative diagnostic tool and have also provided data relating to the absorption and compression phases of laser heating. The x-ray streak camera has been used in conjunction with a specially designed pinhole imaging system to temporally record images of laser compressed targets with a spatial resolution of approximately 6 ..mu..m. Implosion characteristics are presented for experiments with glass microshell targets. The concept, development, and testing of an ultrafast framing camera for full two-dimensional time resolved imaging is discussed. A prototype camera, based on the image dissection-restoration concept, has achieved an approximately 200 psec frame period with a resolution of 50 ..mu..m.

Coleman, L.W.

1976-08-16T23:59:59.000Z

399

The complex soft X-ray spectrum of NGC 4151  

E-Print Network (OSTI)

We present a detailed analysis of the complex soft X-ray spectrum of NGC 4151 measured by the RGS instruments aboard XMM-Newton. The XMM-Newton RGS spectra demonstrate that the soft X-ray emission is extremely rich in X-ray emission lines and radiative recombination continua (RRC), with no clear evidence for any underlying continuum emission. Line emission, and the associated RRC, are clearly detected from hydrogen-like and helium-like ionization states of neon, oxygen, nitrogen and carbon. The measured lines are blueshifted with a velocity of between ?100-1000 km s ?1, with respect to the systemic velocity of NGC 4151, approximately consistent with the outflow velocities of the absorption lines observed in the UV spectrum of NGC 4151 (Kriss et al. 1995), suggestive of an origin for the UV and soft X-ray emission in the same material. Plasma diagnostics from the observed helium-like triplets, imply a range of electron temperatures of ?1-510 4 K and electron densities of between 10 8-10 10 cm ?3. The soft X-ray spectrum of NGC 4151 is extremely similar to that of NGC 1068, both in terms of the atomic species present and in terms of the relative strengths

N. J. Schurch; R. S. Warwick; R. E. Griffiths; S. M. Kahn

2004-01-01T23:59:59.000Z

400

The complex soft X-ray spectrum of NGC 4151  

E-Print Network (OSTI)

We present a detailed analysis of the complex soft X-ray spectrum of NGC 4151 measured by the RGS instruments aboard XMM-Newton. The XMM-Newton RGS spectra demonstrate that the soft X-ray emission is extremely rich in X-ray emission lines and radiative recombination continua (RRC), with no clear evidence for any underlying continuum emission. Line emission, and the associated RRC, are clearly detected from hydrogen-like and helium-like ionization states of neon, oxygen, nitrogen and carbon. The measured lines are blueshifted with a velocity of between ~100-1000 km/s, with respect to the systemic velocity of NGC 4151, approximately consistent with the outflow velocities of the absorption lines observed in the UV, suggestive of an origin for the UV and soft X-ray emission in the same material. Plasma diagnostics imply a range of electron temperatures of ~1-5x10^4 K and electron densities of between 10^8-10^10 cm^-3. The soft X-ray spectrum of NGC 4151 is extremely similar to that of NGC 1068, suggesting that th...

Schurch, N J; Griffiths, R E; Kahn, S M

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

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

402

Flat Field Anomalies in an X-ray CCD Camera Measured Using a Manson X-ray Source  

SciTech Connect

The Static X-ray Imager (SXI) is a diagnostic used at the National Ignition Facility (NIF) to measure the position of the X-rays produced by lasers hitting a gold foil target. The intensity distribution taken by the SXI camera during a NIF shot is used to determine how accurately NIF can aim laser beams. This is critical to proper NIF operation. Imagers are located at the top and the bottom of the NIF target chamber. The CCD chip is an X-ray sensitive silicon sensor, with a large format array (2k x 2k), 24 ?m square pixels, and 15 ?m thick. A multi-anode Manson X-ray source, operating up to 10kV and 10W, was used to characterize and calibrate the imagers. The output beam is heavily filtered to narrow the spectral beam width, giving a typical resolution E/?E?10. The X-ray beam intensity was measured using an absolute photodiode that has accuracy better than 1% up to the Si K edge and better than 5% at higher energies. The X-ray beam provides full CCD illumination and is flat, within 1% maximum to minimum. The spectral efficiency was measured at 10 energy bands ranging from 930 eV to 8470 eV. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation occurred at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was not observable below 4 keV. We were also able to observe debris, damage, and surface defects on the CCD chip. The Manson source is a powerful tool for characterizing the imaging errors of an X-ray CCD imager. These errors are quite different from those found in a visible CCD imager.

M. J. Haugh and M. B. Schneider

2008-10-31T23:59:59.000Z

403

ON THE X-RAY OUTBURSTS OF TRANSIENT ANOMALOUS X-RAY PULSARS AND SOFT GAMMA-RAY REPEATERS  

SciTech Connect

We show that the X-ray outburst light curves of four transient anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs), namely, XTE J1810-197, SGR 0501+4516, SGR 1627-41, and CXOU J164710.2-455216, can be produced by the fallback disk model that was also applied to the outburst light curves of persistent AXPs and SGRs in our earlier work. The model solves the diffusion equation for the relaxation of a disk that has been pushed back by a soft gamma-ray burst. The sets of main disk parameters used for these transient sources are very similar to each other and to those employed in our earlier models of persistent AXPs and SGRs. There is a characteristic difference between the X-ray outburst light curves of transient and persistent sources. This can be explained by the differences in the disk surface density profiles of the transient and persistent sources in quiescence indicated by their quiescent X-ray luminosities. Our results imply that a viscous disk instability operating at a critical temperature in the range of {approx}1300-2800 K is a common property of all fallback disks around AXPs and SGRs. The effect of the instability is more pronounced and starts earlier for the sources with lower quiescent luminosities, which leads to the observable differences in the X-ray enhancement light curves of transient and persistent sources. A single active disk model with the same basic disk parameters can account for the enhancement phases of both transient and persistent AXPs and SGRs. We also present a detailed parameter study to show the effects of disk parameters on the evolution of the X-ray luminosity of AXPs and SGRs in the X-ray enhancement phases.

Cal Latin-Small-Letter-Dotless-I skan, Sirin; Ertan, Uenal [Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul, 34956 (Turkey)

2012-10-20T23:59:59.000Z

404

SLAC | 2011 X-Ray Spectroscopy of Magnetic Solids workshop -...  

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

Abstracts Agenda Location Visitor Information Transportation About XRMS BaBar detector, SLAC LCLS experimental stations, SLAC Panofsky auditorium, SLAC SLAC National Accelerator...

405

Bunch by Bunch Profiling with a Rotating X-ray Mask  

SciTech Connect

It is desirable to monitor the cross sections of each positron bunch in the Low Energy Ring (LER) storage rings of the Positron Electron Project II (PEP-II) located at the Stanford Linear Accelerator Center. One method is to pass the x-rays given off by each bunch through a scintillator, thereby studying a visible image. A rotating x-ray mask with three slots scans the beam image in three different orientations, allowing us to mechanically collect data to characterize and profile each image. Progress was made in designing the x-ray mask, researching and procuring parts, as well as advancing project plans. However, due to time constraints and difficulties in procuring special parts, the full system was not completed. A simpler setup was built to test the hardware as well as the feasibility of characterizing a circular image with a rotating mask. A blinking green light emitting diode (LED) simulated a single positron bunch stored in the LER ring. The selected hardware handled this simulation setup well and produced data that led to a reasonable estimation of the LED image diameter.

Lee, Christopher J.; /UC, San Diego

2007-11-07T23:59:59.000Z

406

Detection sensitivity of x-ray CT imaging for NDE of green-state ceramics  

DOE Green Energy (OSTI)

Improved ceramic-processing methods that use pressure slip-casting and injection molding are being developed at Norton Advanced Ceramics, with a goal of producing reliable structural ceramics for advanced heat engines. Nondestructive evaluation (NDE) of ceramic parts at different stages of processing can provide useful diagnostic information to help improve processing techniques. For example, an evaluation of density gradients in as-cast green-body samples can be used to judge mold performance and make changes in mold design. Also, the ability to detect minute flaws (20 to 50 {mu}m), such as agglomerates, inclusions, and voids, in green-body, presintered, and densified parts is important in ensuring structural reliability of the final parts, because these flaws, above certain critical sizes, can lead to catastrophic failure. Three-dimensional microfocus X-ray computed tomography (CT) and nuclear magnetic resonance imaging (MRI) systems have been developed at Argonne National Laboratory (ANL) for application to quantitative NDE evaluation of ceramics. This paper evaluates the detection sensitivity of the ANL X-ray CT system when used to determine density gradients, inclusions, and voids in green-state Si{sub 3}N{sub 4} ceramics. A theoretical account of key system- and sample-related parameters affecting X-ray CT detection sensitivity is given, and results of experimental evaluation are presented. Density calibration phantoms and net-shape-formed tensile rods with seeded defects were used in the experimental evaluation of detection limits. 6 refs., 6 figs., 1 tab.

Gopalsami, N.; Rizo, P.; Ellingson, W.A. (Argonne National Lab., IL (United States)); Tracey, D.M. (Norton Co., Northboro, MA (United States). Advanced Ceramics Div.)

1991-01-01T23:59:59.000Z

407

Large-scale Nanostructure Simulations from X-ray Scattering Data On Graphics Processor Clusters  

Science Conference Proceedings (OSTI)

X-ray scattering is a valuable tool for measuring the structural properties of materialsused in the design and fabrication of energy-relevant nanodevices (e.g., photovoltaic, energy storage, battery, fuel, and carbon capture andsequestration devices) that are key to the reduction of carbon emissions. Although today's ultra-fast X-ray scattering detectors can provide tremendousinformation on the structural properties of materials, a primary challenge remains in the analyses of the resulting data. We are developing novelhigh-performance computing algorithms, codes, and software tools for the analyses of X-ray scattering data. In this paper we describe two such HPCalgorithm advances. Firstly, we have implemented a flexible and highly efficient Grazing Incidence Small Angle Scattering (GISAXS) simulation code based on theDistorted Wave Born Approximation (DWBA) theory with C++/CUDA/MPI on a cluster of GPUs. Our code can compute the scattered light intensity from any givensample in all directions of space; thus allowing full construction of the GISAXS pattern. Preliminary tests on a single GPU show speedups over 125x compared tothe sequential code, and almost linear speedup when executing across a GPU cluster with 42 nodes, resulting in an additional 40x speedup compared to usingone GPU node. Secondly, for the structural fitting problems in inverse modeling, we have implemented a Reverse Monte Carlo simulation algorithm with C++/CUDAusing one GPU. Since there are large numbers of parameters for fitting in the in X-ray scattering simulation model, the earlier single CPU code required weeks ofruntime. Deploying the AccelerEyes Jacket/Matlab wrapper to use GPU gave around 100x speedup over the pure CPU code. Our further C++/CUDA optimization deliveredan additional 9x speedup.

Sarje, Abhinav; Pien, Jack; Li, Xiaoye; Chan, Elaine; Chourou, Slim; Hexemer, Alexander; Scholz, Arthur; Kramer, Edward

2012-01-15T23:59:59.000Z

408

Analysis and Design of a High Power Density Axial Flux Permanent Magnet Linear Synchronous Machine Used for Stirling System  

Science Conference Proceedings (OSTI)

a high power density axial flux permanent magnet linear synchronous machine and the stirling system will be introduced. This machine is a tubular axial flux permanent magnet machine. It comprises two parts: stator and mover. With the 2D finite-element ... Keywords: permanent magnet, stirling engine, linear motor

Ping Zheng; Xuhui Gan; Lin Li

2010-09-01T23:59:59.000Z

409

X-ray movies reveal insect flight, muscle motion  

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

BioCAT BioCAT X-ray movies reveal insect flight, muscle motion Photo credit: Michael Dickinson Watching flies fly may not seem like high-tech science, but for researchers using the Western Hemisphere's most brilliant X-rays, from the Advanced Photon Source located at the U.S. Department of Energy's Argonne National Laboratory, it not only helps explain how insects fly but also may someday aid in understanding human heart function. The researchers, from the Illinois Institute of Technology (IIT), Caltech and the University of Vermont, merged two distinct technologies, intense X-ray beams and electronic flight simulators, to study how insect muscles can generate such extraordinary levels of power. The results are published in the the January 20,. 2005, issue of the journal Nature.

410

X-ray Microscopy and Imaging (XSD-XMI)  

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

Imaging (XMI) Imaging (XMI) About XMI Science and Research Beamlines Highlights Software and Tools Intranet Search APS... Argonne Home > Advanced Photon Source > Contacts FAQs Beamlines News Publications APS Email Portal APS Intranet APS Phonebook APS Quick Links for Users APS Safety and Training Welcome to the X-ray Microscopy and Imaging group (XMI)! X-ray Microscopy and Imaging is part of the X-ray Science Division at the Advanced Photon Source. We develop and support a diverse and multidisciplinary user research program at Sectors 2 and 32 of the APS, with the overall goal to image and study materials structures at spatial and temporal resolutions that are most scientifically relevant to the cutting-edge advances in materials, biological, environmental, and biomedical sciences. To achieve this goal, we actively engage in various research activities including

411

Workshop on Time Domain Science Using X-ray Techniques  

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

Time-Resolved Beamlines Time-Resolved Beamlines Advisory Committee Workshop Home Workshop Chairs: Lin Chen (Argonne National Laboratory) Steve Milton (Advanced Photon Source) David Reis (University of Michigan) Linda Young (Argonne National Laboratory) Workshop on Time Domain Science Using X-ray Techniques August 29 September 1, 2004, The Abbey, Fontana, Lake Geneva Area, Wisconsin A workshop on "Time Domain Science Using X-ray Techniques" was held from August 29 September 1, 2004 , welcoming both experts and beginners in the field. This is one of the concurrently held workshops in the series on "Future Scientific Directions for the Advanced Photon Source." The goal of the workshop was to identify future directions in scientific research using time resolved x-ray techniques and to address possiblities to produce ps

412

X-RAY FLUORESCENCE MICROPROBE (XFM) TECHNIQUES AND CAPABILITIES  

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

RAY FLUORESCENCE MICROPROBE (XFM) RAY FLUORESCENCE MICROPROBE (XFM) TECHNIQUES AND CAPABILITIES APPLICATIONS WORLD-LEADING MICROFOCUSED EXAFS SPECTROSCOPY * XFM is an optimized three-pole wiggler beamline for the characterization of materials in an "as-is" state that are chemically heterogeneous at the micrometer scale via synchrotron induced X-ray fluorescence. * XFM includes instrumentation for microbeam X-ray fluorescence (µXRF), diffraction (µXRD) and fluorescence computed microtomography (FCMT) . However, it is optimized to provide users state-of-the-art microfocused Extended X-ray Absorption Fine Structure (µEXAFS) spectroscopy between 4 to 20 keV. * XFM will trade-off beam size and flux for sample configuration flexibility. This includes more readily achievable stability

413

X-ray and Optical Filaments in M87  

E-Print Network (OSTI)

We compare a very deep X-ray image of M87, at the center of the Virgo Cluster, to high-quality optical images of the low excitation emission-line gas in the same region. There are striking coincidences of detail between the two. We explore the possiblity that this represents a thermal interaction between hot gas at 10^7 K and warm gas at 10^4 K. We find two temperatures are present in the X-ray gas, with the lower more prevelant in the vicinity of the optical filaments. Electron conduction from the hot phase to the cooler one provides a quantitatively acceptable energy source for the optical filaments, and we show additionally that it can do so for the brightest X-ray cluster, Perseus. If operative, conduction in the presence of gas-rich galaxy mergers, may explain the presence of "cool cores" in clusters of galaxies.

William B. Sparks; Megan Donahue; Andres Jordan; Laura Ferrarese; Patrick Cote

2004-02-09T23:59:59.000Z

414

Composite structure development decisions using X-ray CT measurements  

Science Conference Proceedings (OSTI)

X-ray computed tomography (CT) provides measurement data useful for making composite manufacturing development decisions. X-ray CT measurements of material characteristics are quantitative in terms of the dimensions, density, and composition. The CT data on internal conditions, such as consolidation, gaps, delaminations, cracks, porosity and detail placement can be applied to the refinement of production techniques for composite manufacture. The key item of interest is the effect of variations in pressure loading, temperature, mold shape, material surface preparation, and bond layer thickness on the resulting consolidation or bondline quality in new composite manufacturing processes. X-ray CT measurements of densification and defect presence as a function of technique parameters are of critical importance to processes such as resin transfer molding, injection molding, composite welding, composite layup and advanced bonding methods.

Bossi, R.H.; Georgeson, G.E. [Boeing Defense and Space Group, Seattle, WA (United States)

1995-10-01T23:59:59.000Z

415

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

416

X-ray Detection of a Rotating Radio Transient  

E-Print Network (OSTI)

Abstract Rotating RAdio Transients (RRATs) are a newly discovered astronomical phenomenon, characterised by occasional brief radio bursts, with average intervals between bursts ranging from minutes to hours. The burst spacings allow identification of periodicities, which fall in the range 0.4 to 7 seconds. The RRATs thus seem to be rotating neutron stars, albeit with properties very different from the rest of the population. We here present the serendipitous detection with the Chandra X-ray Observatory of a bright point-like X-ray source coincident with one of the RRATs. We discuss the temporal and spectral properties of this X-ray emission, consider counterparts in other wavebands, and interpret these results in the context of possible explanations for the RRAT population.

Bryan M. Gaensler; Maura Mclaughlin; Stephen Reynolds Kazik; Borkowski N; Burgay Fern; Andrew Lyne; Ingrid Stairs; B. M. Gaensler; S. Chatterjee; M. Mclaughlin; S. Reynolds; K. Borkowski; N. Rea; A. Possenti; M. Burgay; Osservatorio Astronomico Di Roma; F. Camilo; M. Kramer; A. Lyne

2006-01-01T23:59:59.000Z

417

The Use of X-Ray Microbeams in Materials Science  

SciTech Connect

Most materials are heterogeneous on mesoscopic length scales (tenths-to-tens of microns), and materials properties depend critically on mesoscopic structures such as grain sizes, texture, and impurities. The recent availability of intense, focused x-ray microbeams at synchrotron facilities has enabled new techniques for mesoscale materials characterization. We describe instrumentation and experiments on the MHATT-CAT and UNICAT undulator beamlines at the Advanced Photon Source which use micron and submicron-size x-ray beams to investigate the grain orientation, local strain and defect content in a variety of materials of technological interest. Results from a combinatorial study on epitaxial growth of oxide films on textured metal substrates will be described to illustrate x-ray microbeam capabilities.

Budai, J.D.; Chung, J.-S.; Ice, G.E.; Larson, B.C.; Lowe, W.P.; Norton, D.P.; Tamura, N.; Tischler, J.Z.; Williams, E.L.; Yoon, M.; Zschack, P.

1998-10-13T23:59:59.000Z

418

Explosive hydrogen burning during type I X-ray bursts  

E-Print Network (OSTI)

Explosive hydrogen burning in type I X-ray bursts (XRBs) comprise charged particle reactions creating isotopes with masses up to A~100. Since charged particle reactions in a stellar environment are very temperature sensitive, we use a realistic time-dependent general relativistic and self-consistent model of type I x-ray bursts to provide accurate values of the burst temperatures and densities. This allows a detailed and accurate time-dependent identification of the reaction flow from the surface layers through the convective region and the ignition region to the neutron star ocean. Using this, we determine the relative importance of specific nuclear reactions in the X-ray burst.

Jacob Lund Fisker; Hendrik Schatz; Friedrich-Karl Thielemann

2007-03-13T23:59:59.000Z

419

On burning regimes and long duration X-ray bursts  

E-Print Network (OSTI)

Hydrogen and helium accreted onto a neutron star undergo thermonuclear burning. Explosive burning is observed as a type I X-ray burst. We describe the different burning regimes and focus on some of the current inconsistencies between theory and observations. Of special interest are the rare kinds of X-ray bursts such as carbon-fueled superbursts and helium-fueled intermediately long X-ray bursts. These bursts are thought to originate deeper in the neutron star envelope, such that they are probes of the thermal properties of the crust. We investigate the possibility of observing superbursts with the wide-field instruments INTEGRAL-ISGRI and Swift-BAT. We find that only the brightest bursts are detectable.

L. Keek; J. J. M. in 't Zand

2008-11-27T23:59:59.000Z

420

Fast microtomography using bright monochromatic x-rays  

Science Conference Proceedings (OSTI)

A fast microtomography system for high-resolution high-speed imaging has been developed using bright monochromatic x-rays at the BL29XU beamline of SPring-8. The shortest scan time for microtomography we attained was 0.25 s in 1.25 {mu}m effective pixel size by combining the bright monochromatic x-rays, a fast rotating sample stage, and a high performance x-ray imaging detector. The feasibility of the tomography system was successfully demonstrated by visualization of rising bubbles in a viscous liquid, an interesting issue in multiphase flow physics. This system also provides a high spatial (a measurable feature size of 300 nm) or a very high temporal (9.8 {mu}s) resolution in radiographs.

Jung, J. W.; Lee, J. S.; Park, S. J.; Chang, S.; Pyo, J. [X-ray Imaging Center, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); Kwon, N.; Kim, J. [X-ray Imaging Center, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Kohmura, Y.; Nishino, Y.; Yamamoto, M.; Ishikawa, T. [RIKEN/SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148 (Japan); Je, J. H. [X-ray Imaging Center, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784 (Korea, Republic of); School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); RIKEN/SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2012-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "x-ray magnetic linear" 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

Experiment Hazard Class 8.3 - X-Ray Generators  

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

3 - X-Ray Generators 3 - X-Ray Generators Applicability This hazard classification applies to all experiments involving the use of X-Ray Generators (other than the APS storage ring). As specified in LMS-PROC-109 a Radiation Generating Device (RGD) must be registered with the Argonne RGD Safety Officer using the ANL-847 form. The RGD will be assigned an inventory number, hazard class, RWP requirement, and inspection and survey frequencies. Experiment Category Experiments the Experiment Hazard Class are always categorized as High Risk. Experiment Hazard Control Verification Statements Engineered Controls - As determined in LMS-PROC-109. Samples chambers and all beam paths are fully enclosed by barriers. Class 2 and higher RGDs require an interlock to fail-safe beam shutter/beam stop or radiation

422

X-Ray Diffraction Project Final Report, Fiscal Year 2006  

SciTech Connect

An x-ray diffraction diagnostic system was developed for determining real-time shock-driven lattice parameter shifts in single crystals at the gas gun at TA-IV at Sandia National Laboratories (SNL). The signal-to-noise ratio and resolution of the system were measured using imaging plates as the detector and by varying the slit width. This report includes tests of the x-ray diffraction system using a phosphor coupled to a charge-coupled device (CCD) camera by a coherent fiber-optic bundle. The system timing delay was measured with a newly installed transistor-transistor logic (TTL) bypass designed to reduce the x-ray delay time. The axial misalignment of the Bragg planes was determined with respect to the optical axis for a set of eight LiF [lithium fluoride] crystals provided by SNL to determine their suitability for gas gun experiments.

Dane V. Morgan

2006-10-01T23:59:59.000Z

423

A CHANDRA X-RAY OBSERVATION OF THE BINARY MILLISECOND PULSAR PSR J1023+0038  

SciTech Connect

We present a Chandra X-Ray Observatory ACIS-S variability, spectroscopy, and imaging study of the peculiar binary containing the millisecond pulsar J1023+0038. The X-ray emission from the system exhibits highly significant (12.5{sigma}) large-amplitude (factor of two to three) orbital variability over the five consecutive orbits covered by the observation, with a pronounced decline in the flux at all energies at superior conjunction. This can be naturally explained by a partial geometric occultation by the secondary star of an X-ray-emitting intrabinary shock, produced by the interaction of outflows from the two stars. The depth and duration of the eclipse imply that the intrabinary shock is localized near or at the surface of the companion star and close to the inner Lagrangian point. The energetics of the shock favor a magnetically dominated pulsar wind that is focused into the orbital plane, requiring close alignment of the pulsar spin and orbital angular momentum axes. The X-ray spectrum consists of a dominant non-thermal component and at least one thermal component, likely originating from the heated pulsar polar caps, although a portion of this emission may be from an optically thin 'corona'. We find no evidence for extended emission due to a pulsar wind nebula or bow shock down to a limiting luminosity of L{sub X} {approx}< 3.6 Multiplication-Sign 10{sup 29} erg s{sup -1} (0.3-8 keV), {approx}< 7 Multiplication-Sign 10{sup -6} of the pulsar spin-down luminosity, for a distance of 1.3 kpc and an assumed power-law spectrum with photon index {Gamma} = 1.5.

Bogdanov, Slavko; Archibald, Anne M.; Kaspi, Victoria M. [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); Lorimer, Duncan; McLaughlin, Maura A. [Department of Physics, West Virginia University, 210E Hodges Hall, Morgantown, WV 26506 (United States); Ransom, Scott M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22901 (United States); Stairs, Ingrid H. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada)

2011-12-01T23:59:59.000Z

424

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

425

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

426

Concave Accretion Discs and X-ray Reprocessing  

E-Print Network (OSTI)

Spectra of Seyfert Is are commonly modelled as emission from an X-ray illuminated flat accretion disc orbiting a central black hole. This provides both a reprocessed and direct component of the X-ray emission as required by observations of individual objects and possibly a fraction of the cosmological X-ray background. There is some observational motivation to at least consider the role that an effectively concave disc surface might play: (1) a reprocessed fraction $\\gsim 1/2$ in some Seyferts and possibly in the X-ray background, and (2) the commonality of a sharp iron line peak for Seyferts at 6.4KeV despite a dependence of peak location on inclination angle for flat disc models. Here it is shown that a concave disc may not only provide a larger total fraction of reprocessed photons, but can also reprocess a much larger fraction of photons in its outer regions when compared to a flat disc. This reduces the sensitivity of the 6.4KeV peak location to the inner disc inclination angle because the outer regions are less affected by Doppler and gravitational effects. If the X-ray source is isotropic, the reprocessed fraction is directly determined by the concavity. If the X-ray source is anisotropic, the location of iron line peak can still be determined by concavity but the total reflected fraction need not be as large as for the isotropic emitter case. The geometric calculations herein are applicable to general accretion disc systems illuminated from the center.

Eric G. Blackman

1999-01-16T23:59:59.000Z

427

X-ray Diagnostics of Broad Absorption Line Quasar Geometry  

E-Print Network (OSTI)

A new generation of sensitive X-ray measurements are indicating that the existence of X-ray attenuation column densities, $N_{H}>10^{24}\\mathrm{cm}^{-2}$ is quite common amongst broad absorption line quasars (BALQSOs). This is significant to the geometry of the broad absorption line (BAL) outflow. In particular, such an X-ray shield also shields equatorial accretion disk winds from the UV, thereby preventing high velocity equatorial outflows from being launched. By contrast, bipolar winds initiated by continuum radiation pressure from the funnel of a slim accretion disk flare outward (like a trumpet) and offer vastly different absorbing columns to the X-ray and UV emission which are emitted from distinct regions of the disk, $\\sim 6M$ and $\\sim 10M-40M$, respectively (where $M$ is the radius of the black hole). Recent numerical work indicates that it is also possible to launch bipolar outflows from the inner regions of a thin disk. The recent discovery with VLBI that the Galactic analog of a BALQSO, the X-ray binary Circinus X-1 (with high velocity P Cygni X-ray absorption lines) is viewed virtually along the radio jet axis (and therefore along the spin axis of the black hole and the normal to the accretion disk) has rekindled interest in the bipolar models of BALQSOs. We explore this possibility by studying the nearest BAL QSO, MRK 231. High resolution 2-D optical spectroscopy and VLBI mappings of the radio jet axis indicates that the BAL outflow is parallel to the parsec scale radio jet.

Brian Punsly; Sebastian Lipari

2005-03-09T23:59:59.000Z

428

Electronic Structure of Dense Plasmas by X-Ray Scattering  

DOE Green Energy (OSTI)

We present an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes the effects of weakly bound electrons. This result can be applied to describe scattering from low to moderate Z plasmas, and it covers the entire range of plasma conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon plasma and to extract accurate measurements of electron temperature, electron density and charge state. We use our experimental results to validate various equation-of-state models for carbon plasmas.

Gregori, G; Glenzer, S H; Rogers, F J; Pollaine, S M; Froula, D H; Blancard, C; Faussurier, G; Renaudin, P; Kuhlbrodt, S; Redmer, R; Landen, O L

2003-10-07T23:59:59.000Z

429

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

430

Bragg x-ray survey spectrometer for ITER  

Science Conference Proceedings (OSTI)

Several potential impurity ions in the ITER plasmas will lead to loss of confined energy through line and continuum emission. For real time monitoring of impurities, a seven channel Bragg x-ray spectrometer (XRCS survey) is considered. This paper presents design and analysis of the spectrometer, including x-ray tracing by the Shadow-XOP code, sensitivity calculations for reference H-mode plasma and neutronics assessment. The XRCS survey performance analysis shows that the ITER measurement requirements of impurity monitoring in 10 ms integration time at the minimum levels for low-Z to high-Z impurity ions can largely be met.

Varshney, S. K.; Jakhar, S. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India); Barnsley, R. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); O'Mullane, M. G. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2012-10-15T23:59:59.000Z

431

Opportunities for X-ray Science in Future Computing Architectures  

Science Conference Proceedings (OSTI)

The world of computing continues to evolve rapidly. In just the past 10 years, we have seen the emergence of petascale supercomputing, cloud computing that provides on-demand computing and storage with considerable economies of scale, software-as-a-service methods that permit outsourcing of complex processes, and grid computing that enables federation of resources across institutional boundaries. These trends show no sign of slowing down. The next 10 years will surely see exascale, new cloud offerings, and other terabit networks. This talk reviews various of these developments and discusses their potential implications for x-ray science and x-ray facilities.

Foster, Ian [Argonne National Laboratory

2011-02-09T23:59:59.000Z

432

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

433

Cooled window for X-rays or charged particles  

DOE Patents (OSTI)

A window is disclosed that provides good structural integrity and a very high capacity for removal of the heat deposited by x-rays, electrons, or ions, with minimum attenuation of the desired beam. The window is cooled by providing microchannels therein through which a coolant is pumped. For example, the window may be made of silicon with etched microchannels therein and covered by a silicon member. A window made of silicon with a total thickness of 520 {micro}m transmits 96% of the x-rays at an energy of 60 keV, and the transmission is higher than 90% for higher energy photons. 1 fig.

Logan, C.M.

1996-04-16T23:59:59.000Z

434

Cooled window for X-rays or charged particles  

DOE Patents (OSTI)

A window that provides good structural integrity and a very high capacity for removal of the heat deposited by x-rays, electrons, or ions, with minimum attenuation of the desired beam. The window is cooled by providing microchannels therein through which a coolant is pumped. For example, the window may be made of silicon with etched microchannels therein and covered by a silicon member. A window made of silicon with a total thickness of 520 .mu.m transmits 96% of the x-rays at an energy of 60 keV, and the transmission is higher than 90% for higher energy photons.

Logan, Clinton M. (Pleasanton, CA)

1996-01-01T23:59:59.000Z

435

Einstein x-ray observations of cataclysmic variables  

SciTech Connect

Observations with the imaging x-ray detectors on the Einstein Observatory have led to a large increase in the number of low luminosity x-ray sources known to be associated with cataclysmic variable stars (CVs). The high sensitivity of the Einstein instrumentation has permitted study of their short timescale variability and spectra. The data are adding significantly to our knowledge of the accretion process in cataclysmic variables and forcing some revision in our ideas concerning the origin of the optical variability in these stars.

Mason, K.O.; Cordova, F.A.

1982-01-01T23:59:59.000Z

436

SYNCHROTRON X-RAY BASED CHARACTERIZATION OF CDZNTE CRYSTALS  

Science Conference Proceedings (OSTI)

Synthetic CdZnTe or 'CZT' crystals can be used for the room temperature-based detection of {gamma}-radiation. Structural/morphological heterogeneities within CZT, such as twinning, inclusions, and polycrystallinity can affect detector performance. We used a synchrotron-based X-ray technique, specifically extended X-ray absorption fine-structure (EXAFS) spectroscopy, to determine whether there are differences on a local structural level between intact CZT of high and low radiation detector performance. These studies were complemented by data on radiation detector performance and transmission IR imaging. The EXAFS studies revealed no detectable local structural differences between the two types of CZT materials.

Duff, M

2006-09-28T23:59:59.000Z

437

GIANT LOBES OF CENTAURUS A RADIO GALAXY OBSERVED WITH THE SUZAKU X-RAY SATELLITE  

SciTech Connect

We report on Suzaku observations of selected regions within the southern giant lobe of the radio galaxy Centaurus A. In our analysis we focus on distinct X-ray features detected with the X-ray Imaging Spectrometer within the range 0.5-10 keV, some of which are likely associated with fine structure of the lobe revealed by recent high-quality radio intensity and polarization maps. With the available photon statistics, we find that the spectral properties of the detected X-ray features are equally consistent with thermal emission from hot gas with temperatures kT > 1 keV, or with a power-law radiation continuum characterized by photon indices {Gamma} {approx} 2.0 {+-} 0.5. However, the plasma parameters implied by these different models favor a synchrotron origin for the analyzed X-ray spots, indicating that a very efficient acceleration of electrons up to {approx}> 10 TeV energies is taking place within the giant structure of Centaurus A, albeit only in isolated and compact regions associated with extended and highly polarized radio filaments. We also present a detailed analysis of the diffuse X-ray emission filling the whole field of view of the instrument, resulting in a tentative detection of a soft excess component best fitted by a thermal model with a temperature of kT {approx} 0.5 keV. The exact origin of the observed excess remains uncertain, although energetic considerations point to thermal gas filling the bulk of the volume of the lobe and mixed with the non-thermal plasma, rather than to the alternative scenario involving a condensation of the hot intergalactic medium around the edges of the expanding radio structure. If correct, this would be the first detection of the thermal content of the extended lobes of a radio galaxy in X-rays. The corresponding number density of the thermal gas in such a case is n{sub g} {approx} 10{sup -4} cm{sup -3}, while its pressure appears to be in almost exact equipartition with the volume-averaged non-thermal pressure provided by the radio-emitting electrons and the lobes' magnetic field. A prominent large-scale fluctuation of the Galactic foreground emission, resulting in excess foreground X-ray emission aligned with the lobe, cannot be ruled out. Although tentative, our findings potentially imply that the structure of the extended lobes in active galaxies is likely to be highly inhomogeneous and non-uniform, with magnetic reconnection and turbulent acceleration processes continuously converting magnetic energy to internal energy of the plasma particles, leading to possibly significant spatial and temporal variations in the plasma {beta} parameter around the volume-averaged equilibrium condition {beta} {approx} 1.

Stawarz, L.; Gandhi, P.; Takahashi, T.; Takei, Y. [Institute of Space and Astronautical Science JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)] [Institute of Space and Astronautical Science JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Tanaka, Y. T.; Fukazawa, Y. [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)] [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Madejski, G. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)] [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); O'Sullivan, S. P. [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, Sydney, NSW 2006 (Australia)] [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, Sydney, NSW 2006 (Australia); Cheung, C. C. [National Academy of Sciences, Washington, DC 20001 (United States)] [National Academy of Sciences, Washington, DC 20001 (United States); Feain, I. J. [CSIRO Astronomy and Space Science, ATNF, P.O. Box 76, Epping, NSW 1710 (Australia)] [CSIRO Astronomy and Space Science, ATNF, P.O. Box 76, Epping, NSW 1710 (Australia); Hardcastle, M. J. [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom)] [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Kataoka, J.; Takeuchi, Y. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan)] [Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Ostrowski, M. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland)] [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Reville, B. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)] [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Siemiginowska, A. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Simionescu, A.; Werner, N., E-mail: stawarz@astro.isas.jaxa.jp [KIPAC, Stanford University, 452 Lomita Mall, Stanford, CA 94305 (United States)

2013-03-20T23:59:59.000Z

438

Developing small vacuum spark as an x-ray source for calibration of an x-ray focusing crystal spectrometer  

SciTech Connect

A new technique of x-ray focusing crystal spectrometers' calibration is the desired result. For this purpose the spectrometer is designed to register radiated copper K{alpha} and K{beta} lines by using a flat {alpha}-quartz crystal. This experiment uses pre-breakdown x-ray emissions in low vacuum of about 2.5-3 mbar. At this pressure the pinch will not form so the plasma will not radiate. The anode material is copper and the capacity of the capacitor bank is 22.6 nF. This experiment designed and mounted a repetitive triggering system to save the operator time making hundreds of shots. This emission amount is good for calibration and geometrical adjustment of an optical crystal x-ray focusing spectrometer.

Ghomeishi, Mostafa; Adikan, Faisal Rafiq Mahamd [Photonic Research Group, Department of Electrical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Karami, Mohammad [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2012-10-15T23:59:59.000Z

439

Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber  

Science Conference Proceedings (OSTI)

Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton{sup Registered-Sign} windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup.

Manova, D.; Bergmann, A.; Maendl, S.; Neumann, H.; Rauschenbach, B. [Leibniz-Institut fuer Oberflaechenmodifizierung e. V., Permoserstr. 15, 04318 Leipzig (Germany)

2012-11-15T23:59:59.000Z

440

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

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