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Note: This page contains sample records for the topic "theoretical methods x-ray" from the National Library of EnergyBeta (NLEBeta).
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1

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

Science Journals Connector (OSTI)

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

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

2003-06-01T23:59:59.000Z

2

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...

3

Theoretical X-ray Line Profiles from Colliding Wind Binaries  

E-Print Network (OSTI)

We present theoretical X-ray line profiles from a range of model colliding wind systems. In particular, we investigate the effects of varying the stellar mass-loss rates, the wind speeds, and the viewing orientation. We find that a wide range of theoretical line profile shapes is possible, varying with orbital inclination and phase. At or near conjunction, the lines have approximately Gaussian profiles, with small widths (HWHM ~ 0.1 v_infty) and definite blue- or redshifts (depending on whether the star with the weaker wind is in front or behind). When the system is viewed at quadrature, the lines are generally much broader (HWHM ~ v_infty), flat-topped and unshifted. Local absorption can have a major effect on the observed profiles - in systems with mass-loss rates of a few times 10^{-6} Msol/yr the lower energy lines (E wind of the primary. The orbital variation ...

Henley, D B; Pittard, J M

2003-01-01T23:59:59.000Z

4

Theoretical X-ray Line Profiles from Colliding Wind Binaries  

E-Print Network (OSTI)

We present theoretical X-ray line profiles from a range of model colliding wind systems. In particular, we investigate the effects of varying the stellar mass-loss rates, the wind speeds, and the viewing orientation. We find that a wide range of theoretical line profile shapes is possible, varying with orbital inclination and phase. At or near conjunction, the lines have approximately Gaussian profiles, with small widths (HWHM ~ 0.1 v_\\infty) and definite blue- or redshifts (depending on whether the star with the weaker wind is in front or behind). When the system is viewed at quadrature, the lines are generally much broader (HWHM ~ v_\\infty), flat-topped and unshifted. Local absorption can have a major effect on the observed profiles - in systems with mass-loss rates of a few times 10^{-6} Msol/yr the lower energy lines (E wind of the primary. The orbital variation of the line widths and shifts is reduced in a low inclination binary. The extreme case is a binary with i = 0 degrees, for which we would expect no line profile variation.

D. B. Henley; I. R. Stevens; J. M. Pittard

2003-06-23T23:59:59.000Z

5

X-ray laser system, x-ray laser and method  

DOE Patents (OSTI)

Disclosed is an x-ray laser system comprising a laser containing generating means for emitting short wave length radiation, and means external to said laser for energizing said generating means, wherein when the laser is in an operative mode emitting radiation, the radiation has a transverse coherence length to width ratio of from about 0.05 to 1. Also disclosed is a method of adjusting the parameters of the laser to achieve the desired coherence length to laser width ratio.

London, Richard A. (Oakland, CA); Rosen, Mordecai D. (Berkeley, CA); Strauss, Moshe (Omer, IL)

1992-01-01T23:59:59.000Z

6

PHYSICAL PROCESSES SHAPING GAMMA-RAY BURST X-RAY AFTERGLOW LIGHT CURVES: THEORETICAL IMPLICATIONS FROM THE SWIFT X-RAY TELESCOPE OBSERVATIONS  

E-Print Network (OSTI)

PHYSICAL PROCESSES SHAPING GAMMA-RAY BURST X-RAY AFTERGLOW LIGHT CURVES: THEORETICAL IMPLICATIONS August 15; accepted 2005 December 19 ABSTRACT With the successful launch of the Swift Gamma-Ray Burst component is consistent with the tail emission of the prompt gamma-ray bursts and/or the X-ray flares

Zhang, Bing

7

Dense Plasma X-ray Scattering: Methods and Applications  

SciTech Connect

We have developed accurate x-ray scattering techniques to measure the physical properties of dense plasmas. Temperature and density are inferred from inelastic x-ray scattering data whose interpretation is model-independent for low to moderately coupled systems. Specifically, the spectral shape of the non-collective Compton scattering spectrum directly reflects the electron velocity distribution. In partially Fermi degenerate systems that have been investigated experimentally in laser shock-compressed beryllium, the Compton scattering spectrum provides the Fermi energy and hence the electron density. We show that forward scattering spectra that observe collective plasmon oscillations yield densities in agreement with Compton scattering. In addition, electron temperatures inferred from the dispersion of the plasmon feature are consistent with the ion temperature sensitive elastic scattering feature. Hence, theoretical models of the static ion-ion structure factor and consequently the equation of state of dense matter can be directly tested.

Glenzer, S H; Lee, H J; Davis, P; Doppner, T; Falcone, R W; Fortmann, C; Hammel, B A; Kritcher, A L; Landen, O L; Lee, R W; Munro, D H; Redmer, R; Weber, S

2009-08-19T23:59:59.000Z

8

Reflection soft X-ray microscope and method  

DOE Patents (OSTI)

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

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

1993-01-01T23:59:59.000Z

9

X-ray focal spot locating apparatus and method  

DOE Patents (OSTI)

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

Gilbert, Hubert W. (Cedar Crest, NM)

1985-07-30T23:59:59.000Z

10

X-ray mask and method for providing same  

DOE Patents (OSTI)

The present invention describes a method for fabricating an x-ray mask tool which can achieve pattern features having lateral dimension of less than 1 micron. The process uses a thin photoresist and a standard lithographic mask to transfer an trace image pattern in the surface of a silicon wafer by exposing and developing the resist. The exposed portion of the silicon substrate is then anisotropically etched to provide an etched image of the trace image pattern consisting of a series of channels in the silicon having a high depth-to-width aspect ratio. These channels are then filled by depositing a metal such as gold to provide an inverse image of the trace image and thereby providing a robust x-ray mask tool.

Morales, Alfredo M. (Pleasanton, CA); Skala, Dawn M. (Fremont, CA)

2004-09-28T23:59:59.000Z

11

Detection limits of high temperature superconducting materials on various substrates by energy dispersive X-ray fluorescence and proton induced X-ray emission methods  

Science Journals Connector (OSTI)

Application of energy dispersive X-ray fluorescence (EDXRF) and proton induced X-ray emission (PIXE) methods has been demonstrated for determining the elemental composition of thin film superconducting materia...

M Lal; H N Bajpai; D Joseph; R K Choudhury

1990-04-01T23:59:59.000Z

12

Method and apparatus for producing sharp chromatic x-ray images of x-ray emitting objects  

SciTech Connect

Method and apparatus for producing sharp, chromatic, magnified images of X-ray emitting objects, are provided. The apparatus, which constitutes an X-ray microscope or telescope, comprises a connected collection of Bragg reflecting planes, comprised of either a bent crystal or a synthetic multilayer structure, disposed on and adjacent to a locus determined by a spherical surface. The individual Bragg planes are spatially oriented to Bragg reflect radiation from the object location toward the image location. This is accomplished by making the Bragg planes spatially coincident with the surfaces of either a nested series of prolate ellipsoids of revolution, or a nested series of spheres. The spacing between the Bragg reflecting planes can be tailored to control the wavelengths and the amount of the X-radiation that is Bragg reflected to form the X-ray image. 7 figs.

Thoe, R.S.

1990-01-09T23:59:59.000Z

13

Apparatus and method to enhance X-ray production in laser produced plasmas  

DOE Patents (OSTI)

Method and apparatus for generating x-rays for use in, for instance, x-ray photolithography is disclosed. The method of generating x-rays includes the steps of providing a target and irradiating the target with a laser system which produces a train of sub-pulses to generate an x-ray producing plasma. The sub-pulses are of both high intensity and short duration. The apparatus for generating x-rays from a plasma includes a vacuum chamber, a target supported within the chamber and a laser system, including a short storage time laser. 8 figs.

Augustoni, A.L.; Gerardo, J.B.; Raymond, T.D.

1992-12-29T23:59:59.000Z

14

Apparatus and method to enhance X-ray production in laser produced plasmas  

DOE Patents (OSTI)

Method and apparatus for generating x-rays for use in, for instance, x-ray photolithography. The method of generating x-rays includes the steps of providing a target and irradiating the target with a laser system which produces a train of sub-pulses to generate an x-ray producing plasma. The sub-pulses are of both high intensity and short duration. The apparatus for generating x-rays from a plasma includes a vacuum chamber, a target supported within the chamber and a laser system, including a short storage time laser.

Augustoni, Arnold L. (Albuquerque, NM); Gerardo, James B. (Albuquerque, NM); Raymond, Thomas D. (Albuquerque, NM)

1992-01-01T23:59:59.000Z

15

Theoretical study of the magnetic x-ray dichroism of Os, Ir, Pt, and Au impurities in Fe  

Science Journals Connector (OSTI)

The electronic structure of the 5d impurities Os, Ir, Pt, and Au in ferromagnetic Fe has been studied by the spin-polarized, relativistic version of the Korringa-Kohn-Rostoker Green’s-function method. This approach simultaneously treats spin polarization and spin-orbit coupling and naturally allows for a theoretical investigation of effects arising from an interplay of both. Here the polarization dependence of x-ray absorption (magnetic x-ray dichroism) is considered. For all the impurities studied, the agreement with recent experimental L2 and L3 absorption spectra is very satisfactory. For Pt in Fe, a decomposition of the spectra into various absorption channels is presented and the applicability of a simplified model is discussed that interprets the spectra in terms of a spin-polarized band structure alone.

H. Ebert and R. Zeller

1990-08-15T23:59:59.000Z

16

Flow method and apparatus for screening chemicals using micro x-ray fluorescence  

DOE Patents (OSTI)

Method and apparatus for screening chemicals using micro x-ray fluorescence. A method for screening a mixture of potential pharmaceutical chemicals for binding to at least one target binder involves flow-separating a solution of chemicals and target binders into separated components, exposing them to an x-ray excitation beam, detecting x-ray fluorescence signals from the components, and determining from the signals whether or not a binding event between a chemical and target binder has occurred.

Warner, Benjamin P. (Los Alamos, NM); Havrilla, George J. (Los Alamos, NM); Miller, Thomasin C. (Bartlesville, OK); Lewis, Cris (Los Alamos, NM); Mahan, Cynthia A. (Los Alamos, NM); Wells, Cyndi A. (Los Alamos, NM)

2009-04-14T23:59:59.000Z

17

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

18

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

19

Method and apparatus for producing durationally short ultraviolet or x-ray laser pulses  

DOE Patents (OSTI)

A method and apparatus is disclosed for producing ultraviolet or x- ray laser pulses of short duration. An ultraviolet or x-ray laser pulse of long duration is progressively refracted, across the surface of an opaque barrier, by a streaming plasma that is produced by illuminating a solid target with a pulse of conventional line focused high power laser radiation. The short pulse of ultraviolet or x-ray laser radiation, which may be amplified to high power, is separated out by passage through a slit aperture in the opaque barrier.

MacGowan, B.J.; Matthews, D.L.; Trebes, J.E.

1987-05-05T23:59:59.000Z

20

Method and apparatus for producing durationally short ultraviolet or X-ray laser pulses  

DOE Patents (OSTI)

A method and apparatus is disclosed for producing ultraviolet or X-ray laser pulses of short duration (32). An ultraviolet or X-ray laser pulse of long duration (12) is progressively refracted, across the surface of an opaque barrier (28), by a streaming plasma (22) that is produced by illuminating a solid target (16, 18) with a pulse of conventional line focused high power laser radiation (20). The short pulse of ultraviolet or X-ray laser radiation (32), which may be amplified to high power (40, 42), is separated out by passage through a slit aperture (30) in the opaque barrier (28).

MacGowan, Brian J. (Livermore, CA); Matthews, Dennis L. (El Granada, CA); Trebes, James E. (Livermore, CA)

1988-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

Method for detecting binding events using micro-X-ray fluorescence spectrometry  

DOE Patents (OSTI)

Method for detecting binding events using micro-X-ray fluorescence spectrometry. Receptors are exposed to at least one potential binder and arrayed on a substrate support. Each member of the array is exposed to X-ray radiation. The magnitude of a detectable X-ray fluorescence signal for at least one element can be used to determine whether a binding event between a binder and a receptor has occurred, and can provide information related to the extent of binding between the binder and receptor.

Warner, Benjamin P. (Los Alamos, NM); Havrilla, George J. (Los Alamos, NM); Mann, Grace (Hong Kong, HK)

2010-12-28T23:59:59.000Z

22

Probing Material Reactivity Using X-ray Pair Distribution Function Methods  

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

Material Reactivity Using X-ray Pair Distribution Material Reactivity Using X-ray Pair Distribution Function Methods Karena W. Chapman X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA Understanding how advanced functional materials react and transform, at an atomic scale, is a characterization challenge with many diverse phenomena possible; components with varying particle size, morphology, and microstructure can evolve from multi-atom clusters to multi-million atom crystals. The pair distribution function (PDF) method shows great promise for providing quantitative insight such reactions. Recent advances in experimental methods, have improved the efficiency of X-ray PDF measurements, to allow time-resolved experiments with sufficient resolution to study reactions in solid

23

Physical processes shaping GRB X-ray afterglow lightcurves: theoretical implications from the Swift XRT observations  

E-Print Network (OSTI)

(Abridged) The Swift X-Ray Telescope (XRT) reveals some interesting features of early X-ray afterglows, including a distinct rapidly decaying component preceding the conventional afterglow component in many sources, a shallow decay component before the more ``normal'' decay component observed in a good fraction of GRBs (e.g. GRB 050128, GRB 050315, GRB 050319, and GRB 050401), and X-ray flares in nearly half of the afterglows (e.g. GRB 050406, GRB 050502B, GRB 050607, and GRB 050724). In this paper, we systematically analyze the possible physical processes that shape the properties of the early X-ray afterglow lightcurves, and use the data to constrain various models. We suggest that the steep decay component is consistent with the tail emission of the prompt gamma-ray bursts and/or of the X-ray flares. This provides clear evidence that the prompt emission and afterglow emission are two distinct components, supporting the internal origin of the GRB prompt emission. The shallow decay segment observed in a group of GRBs suggests that the forward shock keeps being refreshed for some time. This might be caused either by a long-lived central engine, or by a power law distribution of the shell Lorentz factors, or else by the deceleration of a Poynting flux dominated flow. X-ray flares suggest that the GRB central engine is still active after the prompt gamma-ray emission is over, but with a reduced activity at later times. In some cases, the central engine activity even extends days after the burst trigger. Analyses of early X-ray afterglow data reveal that GRBs are indeed highly relativistic events. Early afterglow data of many bursts, starting from the beginning of the XRT observations, are consistent with the afterglow emission from an interstellar medium (ISM) environment.

Bing Zhang; Y. Z. Fan; Jaroslaw Dyks; Shiho Kobayashi; Peter Meszaros; David N. Burrows; John A. Nousek; Neil Gehrels

2005-12-20T23:59:59.000Z

24

X-RAY FLUORESCENCE ANALYSIS OF HANFORD LOW ACTIVITY WASTE SIMULANTS METHOD DEVELOPMENT  

SciTech Connect

The x-ray fluorescence laboratory (XRF) in the Analytical Development Directorate (ADD) of the Savannah River National Laboratory (SRNL) was requested to develop an x-ray fluorescence spectrometry method for elemental characterization of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) pretreated low activity waste (LAW) stream to the LAW Vitrification Plant. The WTP is evaluating the potential for using XRF as a rapid turnaround technique to support LAW product compliance and glass former batching. The overall objective of this task was to develop an XRF analytical method that provides rapid turnaround time (<8 hours), while providing sufficient accuracy and precision to determine variations in waste.

Jurgensen, A; David Missimer, D; Ronny Rutherford, R

2007-08-08T23:59:59.000Z

25

X-ray Method Shows How Frog Embryos Could Help Thwart Disease  

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

Nanocrystals Grow from Liquid Interface Nanocrystals Grow from Liquid Interface Eleventh Arthur H. Compton Award Announced Borland Awarded ACFA-IPAC'13 Prize for Accelerator Science President Obama at the Advanced Photon Source Von Dreele Receives Hanawalt Award APS News Archives: 2012 | 2011 | 2010 | 2009 2008 | 2007 | 2006 | 2005 2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed X-ray Method Shows How Frog Embryos Could Help Thwart Disease MAY 20, 2013 Bookmark and Share X-ray phase-contrast tomography: Early frog embryo in cellular resolution (left) and cell and tissue motion captured and visualized using flow analysis (right). Image: Alexey Ershov/KIT From R&D Magazine online: An international team of scientists using a new X-ray method recorded the internal structure and cell movement inside a living frog embryo in greater

26

Method for the construction of x-ray shielding masks  

SciTech Connect

A method is described for the production of a rigid model of a patient's face onto which lead shielding sheets may be contoured. The model is cast in Lipowitz's metal using a plaster mold.

Canup, D.; Ekstrand, K.E.

1982-03-01T23:59:59.000Z

27

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

Science Journals Connector (OSTI)

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

2014-01-01T23:59:59.000Z

28

Methods for deconvoluting and interpreting complex gamma- and x-ray spectral regions  

SciTech Connect

Germanium and silicon detectors are now widely used for the detection and measurement of x and gamma radiation. However, some analysis situations and spectral regions have heretofore been too complex to deconvolute and interpret by techniques in general use. One example is the L x-ray spectrum of an element taken with a Ge or Si detector. This paper describes some new tools and methods that were developed to analyze complex spectral regions; they are illustrated with examples.

Gunnink, R.

1983-06-01T23:59:59.000Z

29

Theoretical description of field-induced magnetic circular x-ray dichroism in nonmagnetic solids  

Science Journals Connector (OSTI)

It is demonstrated that the presence of an external magnetic field for a paramagnetic solid gives rise to a circular magnetic dichroism in x-ray dichroism (MCXD) in full analogy to the MCXD observed in ferromagnetic solids. It is shown that the conventional sum rules can be adopted for this situation to give access to the spin and orbital susceptibilities. Results of calculations for various transition metal systems demonstrate the applicability of the sum rules. In particular, for the alloy systems AgxPd1-x and AgxPt1-x use of the field induced MCXD should allow us to study in detail the Stoner enhancement of the spin susceptibility as well as the role of the orbital susceptibility of Pd and Pt, respectively.

S. Mankovsky and H. Ebert

2004-01-23T23:59:59.000Z

30

A new method for nondestructive evaluation of solid wood moisture content based on dual-energy X-ray absorptiometry  

Science Journals Connector (OSTI)

This paper presents a new method to determine the moisture content of solid wood based on the principle of dual-energy X-ray absorptiometry. The study investigates the ... obtained equation is proposed to calcula...

Takashi Tanaka; Yasuo Kawai

2013-11-01T23:59:59.000Z

31

A grating-based single-shot x-ray phase contrast and diffraction method for in vivo imaging  

SciTech Connect

Purpose: The purpose of this study is to develop a single-shot version of the grating-based phase contrast x-ray imaging method and demonstrate its capability of in vivo animal imaging. Here, the authors describe the principle and experimental results. They show the source of artifacts in the phase contrast signal and optimal designs that minimize them. They also discuss its current limitations and ways to overcome them. Methods: A single lead grid was inserted midway between an x-ray tube and an x-ray camera in the planar radiography setting. The grid acted as a transmission grating and cast periodic dark fringes on the camera. The camera had sufficient spatial resolution to resolve the fringes. Refraction and diffraction in the imaged object manifested as position shifts and amplitude attenuation of the fringes, respectively. In order to quantify these changes precisely without imposing a fixed geometric relationship between the camera pixel array and the fringes, a spatial harmonic method in the Fourier domain was developed. The level of the differential phase (refraction) contrast as a function of hardware specifications and device geometry was derived and used to guide the optimal placement of the grid and object. Both ex vivo and in vivo images of rodent extremities were collected to demonstrate the capability of the method. The exposure time using a 50 W tube was 28 s. Results: Differential phase contrast images of glass beads acquired at various grid and object positions confirmed theoretical predictions of how phase contrast and extraneous artifacts vary with the device geometry. In anesthetized rats, a single exposure yielded artifact-free images of absorption, differential phase contrast, and diffraction. Differential phase contrast was strongest at bone-soft tissue interfaces, while diffraction was strongest in bone. Conclusions: The spatial harmonic method allowed us to obtain absorption, differential phase contrast, and diffraction images, all from a single raw image and is feasible in live animals. Because the sensitivity of the method scales with the density of the gratings, custom microfabricated gratings should be superior to off-the-shelf lead grids.

Bennett, Eric E.; Kopace, Rael; Stein, Ashley F.; Wen Han [National Heart, Lung, and Blood Institute, National Institutes of Health, Imaging Physics Section, Translational Medicine Branch, 10 Center Drive, MSC 1061, Bethesda, Maryland 20892 (United States)

2010-11-15T23:59:59.000Z

32

Transverse coherence saturation: A method to enhance the coherence of x-ray beams  

Science Journals Connector (OSTI)

A method is proposed to generate improved coherence in x-ray beams. The method leaves the photon source unchanged, and improves transverse coherence by reordering the emitted radiation through dynamical optical means (i.e., with at least one moving optical component). Since the method increases the transverse coherence of beams, it thus reduces the time needed to perform certain types of observations, such as in microscopy, and interference experiments such as holography. It does not increase the longitudinal coherence of beams. However, it can be supplemented by other means to increase longitudinal coherence. It does not increase the brightness, but allows one to more efficiently utilize beams of a given brightness. The use of this method with photons generated by pulsed electron beams, including those in storage rings, seems particularly appropriate.

Paul L. Csonka

1990-06-01T23:59:59.000Z

33

A New Method for the Detection of Galaxy Clusters in X-Ray Surveys  

SciTech Connect

For many years the power of counting clusters of galaxies as a function of their mass has been recognized as a powerful cosmological probe; however, we are only now beginning to acquire data from dedicated surveys with sufcient sky coverage and sensitivity to measure the cluster population out to distances where the dark energy came to dominate the Universe’s evolution. One such survey uses the XMM X-ray telescope to scan a large area of sky, detecting the X-ray photons from the hot plasma that lies in the deep potential wells of massive clusters of galaxies. These clusters appear as extended (not point-like) objects, each providing just a few hundred photons in a typical observation. The detection of extended sources in such a low signal-to-noise situation is an important problem in astrophysics: we attempt to solve it by using as much prior information as possible, translating our experience with wellmeasured clusters to define a “template” cluster that can be varied and matched to the features seen in the XMM images. In this work we adapt an existing Monte Carlo analysis code for this problem. Two detection templates were dened and their suitability explored using simulated data; the method was then applied to a publically avalable XMM observation of a “blank” field. Presented are the encouraging results of this series of experiments, suggesting that this approach continue to be developed for future cluster-identication endeavours.

Piacentine, J.M.; Marshall, P.J.; Peterson, J.R.; Andersson, K.E.

2005-01-01T23:59:59.000Z

34

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

35

A theoretical model for the x-ray luminescence of granular phosphor G. E. Giakoumakis, M. C. Katsarioti, and I. E. Lagaris  

E-Print Network (OSTI)

A theoretical model for the x-ray luminescence of granular phosphor screens G. E. Giakoumakis, M. C-ray luminescence of a phosphor screen is presented. The model takes into account the granular structure of the screen and the random deposition of the phosphor grains on the screen substrate. Results based

Lagaris, Isaac

36

A New Method for Measuring X-ray Optics Aberrations | Advanced Photon  

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

New Clues for Asthma Treatment New Clues for Asthma Treatment Extending Resonant Diffraction to Very High Energies for Structural Studies of Complex Materials Tuning the Collective Properties of Artificial Nanoparticle Supercrystals The Workings of a Key Staph Enzyme and How to Block It Simple Lithium Is Good For Many Surprises Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed A New Method for Measuring X-ray Optics Aberrations MARCH 31, 2011 Bookmark and Share Top: Experimental setup. Bottom: Measured and simulated lens aberrations (left) and their corresponding through focus amplitude of reconstructions (right) for different lens angular misalignments. (From Manuel

37

Method for improving x-ray diffraction determinations of residual stress in nickel-base alloys  

DOE Patents (OSTI)

A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys is discussed. Part of a predetermined area of the surface of a nickel-base alloy is covered with a dispersion. This exposes the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose, since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample. 2 figs.

Berman, R.M.; Cohen, I.

1988-04-26T23:59:59.000Z

38

Robustness of phase retrieval methods in x-ray phase contrast imaging: A comparison  

SciTech Connect

Purpose: The robustness of the phase retrieval methods is of critical importance for limiting and reducing radiation doses involved in x-ray phase contrast imaging. This work is to compare the robustness of two phase retrieval methods by analyzing the phase maps retrieved from the experimental images of a phantom. Methods: Two phase retrieval methods were compared. One method is based on the transport of intensity equation (TIE) for phase contrast projections, and the TIE-based method is the most commonly used method for phase retrieval in the literature. The other is the recently developed attenuation-partition based (AP-based) phase retrieval method. The authors applied these two methods to experimental projection images of an air-bubble wrap phantom for retrieving the phase map of the bubble wrap. The retrieved phase maps obtained by using the two methods are compared. Results: In the wrap's phase map retrieved by using the TIE-based method, no bubble is recognizable, hence, this method failed completely for phase retrieval from these bubble wrap images. Even with the help of the Tikhonov regularization, the bubbles are still hardly visible and buried in the cluttered background in the retrieved phase map. The retrieved phase values with this method are grossly erroneous. In contrast, in the wrap's phase map retrieved by using the AP-based method, the bubbles are clearly recovered. The retrieved phase values with the AP-based method are reasonably close to the estimate based on the thickness-based measurement. The authors traced these stark performance differences of the two methods to their different techniques employed to deal with the singularity problem involved in the phase retrievals. Conclusions: This comparison shows that the conventional TIE-based phase retrieval method, regardless if Tikhonov regularization is used or not, is unstable against the noise in the wrap's projection images, while the AP-based phase retrieval method is shown in these experiments to be superior to the TIE-based method for the robustness in performing the phase retrieval.

Yan, Aimin; Wu, Xizeng; Liu, Hong [Department of Radiology, University of Alabama at Birmingham, Birmingham, Alabama 35233 (United States); Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States)

2011-09-15T23:59:59.000Z

39

Method and apparatus for analog signal conditioner for high speed, digital x-ray spectrometer  

DOE Patents (OSTI)

A signal processing system which accepts input from an x-ray detector-preamplifier and produces a signal of reduced dynamic range for subsequent analog-to-digital conversion is disclosed. The system conditions the input signal to reduce the number of bits required in the analog-to-digital converter by removing that part of the input signal which varies only slowly in time and retaining the amplitude of the pulses which carry information about the x-rays absorbed by the detector. The parameters controlling the signal conditioner`s operation can be readily supplied in digital form, allowing it to be integrated into a feedback loop as part of a larger digital x-ray spectroscopy system. 13 figs.

Warburton, W.K.; Hubbard, B.

1999-02-09T23:59:59.000Z

40

Method and apparatus for analog signal conditioner for high speed, digital x-ray spectrometer  

DOE Patents (OSTI)

A signal processing system which accepts input from an x-ray detector-preamplifier and produces a signal of reduced dynamic range for subsequent analog-to-digital conversion. The system conditions the input signal to reduce the number of bits required in the analog-to-digital converter by removing that part of the input signal which varies only slowly in time and retaining the amplitude of the pulses which carry information about the x-rays absorbed by the detector. The parameters controlling the signal conditioner's operation can be readily supplied in digital form, allowing it to be integrated into a feedback loop as part of a larger digital x-ray spectroscopy system.

Warburton, William K. (1300 Mills St., Menlo Park, CA 94025); Hubbard, Bradley (Santa Cruz, CA)

1999-01-01T23:59:59.000Z

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


41

Theoretical Fe L2,3- and K-edge x-ray magnetic circular dichroism spectra of free iron clusters  

Science Journals Connector (OSTI)

A fully relativistic ab initio theoretical scheme is employed for investigating L2,3- and K-edge x-ray absorption near-edge structure (XANES) and x-ray magnetic circular dichroism (XMCD) spectra of free Fe clusters of 9–89 atoms. The L2,3-edge spectra of clusters differ from spectra of bulk only quantitatively; a higher degree of localization of the d electrons in clusters is reflected through a higher intensity of the main XANES and XMCD peaks at the absorption edge. The K-edge XANES and XMCD spectra of clusters, on the other hand, differ from their bulk counterparts more significantly, even for the largest clusters investigated within our study. Several features, which could serve as spectroscopic markers of the difference between the clusters and bulk, were identified in both the L2,3- and K-edge spectra. Contracting the bond lengths in clusters changes XMCD spectra only quantitatively.

Ond?ej Šipr and Hubert Ebert

2005-10-05T23:59:59.000Z

42

A new method of observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager  

E-Print Network (OSTI)

A new method of observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar, for observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager RHESSI. INTRODUCTION The Reuven Ramaty High-Energy Solar Spectroscopic Imager, RHESSI,1 is a space-based solar x

California at Berkeley, University of

43

Method and apparatus for digitally based high speed x-ray spectrometer  

DOE Patents (OSTI)

A high speed, digitally based, signal processing system which accepts input data from a detector-preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system achieves high throughputs at low cost by dividing the required digital processing steps between a ``hardwired`` processor implemented in combinatorial digital logic, which detects the presence of the x-ray signals in the digitized data stream and extracts filtered estimates of their amplitudes, and a programmable digital signal processing computer, which refines the filtered amplitude estimates and bins them to produce the desired spectral analysis. One set of algorithms allow this hybrid system to match the resolution of analog systems while operating at much higher data rates. A second set of algorithms implemented in the processor allow the system to be self calibrating as well. The same processor also handles the interface to an external control computer. 19 figs.

Warburton, W.K.; Hubbard, B.

1997-11-04T23:59:59.000Z

44

Method and apparatus for digitally based high speed x-ray spectrometer  

DOE Patents (OSTI)

A high speed, digitally based, signal processing system which accepts input data from a detector-preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system achieves high throughputs at low cost by dividing the required digital processing steps between a "hardwired" processor implemented in combinatorial digital logic, which detects the presence of the x-ray signals in the digitized data stream and extracts filtered estimates of their amplitudes, and a programmable digital signal processing computer, which refines the filtered amplitude estimates and bins them to produce the desired spectral analysis. One set of algorithms allow this hybrid system to match the resolution of analog systems while operating at much higher data rates. A second set of algorithms implemented in the processor allow the system to be self calibrating as well. The same processor also handles the interface to an external control computer.

Warburton, William K. (1300 Mills St., Menlo Park, CA 94025); Hubbard, Bradley (Santa Cruz, CA)

1997-01-01T23:59:59.000Z

45

Theoretical treatments of the bound-free contribution and experimental best practice in X-ray Thomson scattering from warm dense matter  

SciTech Connect

By comparison with high-resolution synchrotron x-ray experimental results, we assess several theoretical treatments for the bound-free (core-electron) contribution to x-ray Thomson scattering (i.e., also known as nonresonant inelastic x-ray scattering). We identify an often overlooked source of systematic error in the plane-wave form factor approximation (PWFFA) used in the inference of temperature, ionization state, and free electron density in some laser-driven compression studies of warm dense matter. This error is due to a direct violation of energy conservation in the PWFFA. We propose an improved practice for the bound-free term that will be particularly relevant for XRTS experiments performed with somewhat improved energy resolution at the National Ignition Facility or the Linac Coherent Light Source. Our results raise important questions about the accuracy of state variable determination in XRTS studies, given that the limited information content in low-resolution XRTS spectra does not strongly constrain the models of electronic structure being used to fit the spectra.

Mattern, Brian A.; Seidler, Gerald T. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States)

2013-02-15T23:59:59.000Z

46

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

47

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

E-Print Network (OSTI)

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

Limburg, Karin E.

48

X-Ray Spectra for Bone Quality Assessment Using Energy Dispersive Counting and Imaging Detectors with Dual Energy Method  

Science Journals Connector (OSTI)

The aim of the present study was the optimization of dual energy x-ray spectra through the estimation of ... monoenergetic x-ray beams provides the optimum dual energy pairs minimizing the CV. Single and double ....

P. Sotiropoulou; G. Fountos; N. Martini…

2014-01-01T23:59:59.000Z

49

High-Resolution Soft X-Ray Spectral Analysis in the CK Region of Titanium Carbide (TiC) using the DV-X alpha Molecular Orbital Method  

SciTech Connect

We used the DV-X alpha method to analyze the high-resolution soft X-ray emission and absorption spectra in the CK region of titanium carbide (TiC). The spectral profiles of the X-ray emission and absorption can be ssuscfucelly reproduced by the occupied and unoccupied density of states (DOS ), respectively, in the C2p orbitals of the center carbon atoms in a Ti62C63 cluster model, suggesting that the center carbon atom in a large cluster model expanded to the cubic-structured 53 (= 125) atoms provides sufficient DOS for the X-ray spectral analysis of rock-salt structured metal carbides.

Shimomura, Kenta; Muramatsu, Yasuji; Denlinger, Jonathan D.; Gullikson, Eric M.

2008-10-31T23:59:59.000Z

50

Soft x-ray coherent scattering: Instrument and methods at ESRF ID08  

SciTech Connect

An experimental setup has been developed to perform soft x-ray coherent scattering at beamline ID08 of the European Synchrotron Radiation Facility. An intense coherent beam was obtained by filtering the primary beam with the monochromator and a circular pinhole. A pinhole holder with motorized translations was installed inside the UHV chamber of the diffractometer. The scattered intensity was recorded in reflection geometry with a back-illuminated charge coupled device camera. As a demonstration we report experimental results of resonant magnetic scattering using coherent beam. The degree of coherence is evaluated, and it is shown that, while the vertical coherence is much higher than the horizontal one at the source, the situation is reversed at the diffractometer. The intensity of the coherent beam is also discussed.

Beutier, Guillaume; Marty, Alain; Livet, Frederic; Laan, Gerrit van der; Stanescu, Stefan; Bencok, Peter [DRFMC, SP2M, CEA Grenoble, 17 avenue des Martyrs, 38054 Grenoble Cedex (France); LTPCM, INPG-UJF-CNRS, BP 75, 38402 St. Martin d'Heres (France); Magnetic Spectroscopy Group, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); ESRF, 6 rue Jules Horowitz, BP 220, 38043 Grenoble Cedex (France)

2007-09-15T23:59:59.000Z

51

Self-propagating high-temperature synthesis by the method of x-ray diffraction analysis using synchrotron radiation  

SciTech Connect

Investigations of the dynamics of phase transformations accompanying self-propagating high-temperature synthesis by the method of x-ray diffraction analysis on a synchroton-radiation diffractometer offers the possibility of obtaining data on the dynamics of phase transformations, of observing unstable or unknown phases, of discovering liquid phases, of refining the models of the wave structure, and of obtaining data on the kinetics of formation of each of the phases participating in the synthesis process. This paper reviews the actual results in all of these areas to date and anticipates advances likely under each possibility.

Aleksandrov, V.V.; Korchagin, M.A.; Sheromov, M.A.; Tolochko, B.P.

1984-01-01T23:59:59.000Z

52

Spectroscopic imaging, diffraction, and holography with x-ray photoemission  

SciTech Connect

X-ray probes are capable of determining the spatial structure of an atom in a specific chemical state, over length scales from about a micron all the way down to atomic resolution. Examples of these probes include photoemission microscopy, energy-dependent photoemission diffraction, photoelectron holography, and X-ray absorption microspectroscopy. Although the method of image formation, chemical-state sensitivity, and length scales can be very different, these X-ray techniques share a common goal of combining a capability for structure determination with chemical-state specificity. This workshop will address recent advances in holographic, diffraction, and direct imaging techniques using X-ray photoemission on both theoretical and experimental fronts. A particular emphasis will be on novel structure determinations with atomic resolution using photoelectrons.

Not Available

1992-02-01T23:59:59.000Z

53

X-ray Raman scattering study of aligned polyfluorene  

E-Print Network (OSTI)

We present a non-resonant inelastic x-ray scattering study at the carbon K-edge on aligned poly[9,9-bis(2-ethylhexyl)-fluorene-2,7-diyl] and show that the x-ray Raman scattering technique can be used as a practical alternative to x-ray absorption measurements. We demonstrate that this novel method can be applied to studies on aligned $\\pi$-conjugated polymers complementing diffraction and optical studies. Combining the experimental data and a very recently proposed theoretical scheme we demonstrate a unique property of x-ray Raman scattering by performing the symmetry decomposition on the density of unoccupied electronic states into $s$- and $p$-type symmetry contributions.

S. Galambosi; M. Knaapila; J. A. Soininen; K. Nyg\\aard; S. Huotari; F. Galbrecht; U. Scherf; A. P. Monkman; K. Hämäläinen

2006-08-29T23:59:59.000Z

54

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

55

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

56

Methods for assisting recovery of damaged brain and spinal cord using arrays of X-Ray microplanar beams  

DOE Patents (OSTI)

A method of assisting recovery of an injury site of brain or spinal cord injury includes providing a therapeutic dose of X-ray radiation to the injury site through an array of parallel microplanar beams. The dose at least temporarily removes regeneration inhibitors from the irradiated regions. Substantially unirradiated cells surviving between the microplanar beams migrate to the in-beam irradiated portion and assist in recovery. The dose may be administered in dose fractions over several sessions, separated in time, using angle-variable intersecting microbeam arrays (AVIMA). Additional doses may be administered by varying the orientation of the microplanar beams. The method may be enhanced by injecting stem cells into the injury site.

Dilmanian, F. Avraham (Yaphank, NY); McDonald, III, John W. (Baltimore, MD)

2007-12-04T23:59:59.000Z

57

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

E-Print Network (OSTI)

Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794, USA 2 DepartmentAbsolute x-ray energy calibration over a wide energy range using a diffraction-based iterative;REVIEW OF SCIENTIFIC INSTRUMENTS 83, 063901 (2012) Absolute x-ray energy calibration over a wide energy

Duffy, Thomas S.

58

Resonant Soft X-Ray Contrast Variation Methods as Composition-Specific Probes of Thin Polymer Film Structure  

SciTech Connect

We have developed complementary soft x-ray scattering and reflectometry techniques that allow for the morphological analysis of thin polymer films without resorting to chemical modification or isotopic 2 labeling. With these techniques, we achieve significant, x-ray energy-dependent contrast between carbon atoms in different chemical environments using soft x-ray resonance at the carbon edge. Because carbon-containing samples absorb strongly in this region, the scattering length density depends on both the real and imaginary parts of the atomic scattering factors. Using a model polymer film of poly(styrene-b-methyl methacrylate), we show that the soft x-ray reflectivity data is much more sensitive to these atomic scattering factors than the soft x-ray scattering data. Nevertheless, fits to both types of data yield useful morphological details on the polymer?slamellar structure that are consistent with each other and with literature values.

Welch, Cynthia; Welch, Cynthia F.; Hjelm, Rex P.; Mang, Joseph T.; Hawley, Marilyn E.; Wrobleski, Debra A.; Orler, E. Bruce; Kortright, Jeffrey B

2008-04-04T23:59:59.000Z

59

Synchrotron-Radiation Induced X-Ray Emission (SRIXE)  

SciTech Connect

Elemental analysis using emission of characteristic x rays is a well-established scientific method. The success of this analytical method is highly dependent on the properties of the source used to produce the x rays. X-ray tubes have long existed as a principal excitation source, but electron and proton beams have also been employed extensively. The development of the synchrotron radiation x-ray source that has taken place during the past 40 years has had a major impact on the general field of x-ray analysis. Even tier 40 years, science of x-ray analysis with synchrotron x-ray beams is by no means mature. Improvements being made to existing synchrotron facilities and the design and construction of new facilities promise to accelerate the development of the general scientific use of synchrotron x-ray sources for at least the next ten years. The effective use of the synchrotron source technology depends heavily on the use of high-performance computers for analysis and theoretical interpretation of the experimental data. Fortunately, computer technology has advanced at least as rapidly as the x-ray technology during the past 40 years and should continue to do so during the next decade. The combination of these technologies should bring about dramatic advances in many fields where synchrotron x-ray science is applied. It is interesting also to compare the growth and rate of acceptance of this particular research endeavor to the rates for other technological endeavors. Griibler [1997] cataloged the time required for introduction, diffusion,and acceptance of technological, economic, and social change and found mean values of 40 to 50 years. The introduction of the synchrotron source depends on both technical and non-technical factors, and the time scale at which this seems to be occurring is quite compatible with what is seen for other major innovations such as the railroad or the telegraph. It will be interesting to see how long the present rate of technological change and increase in scientific use can be maintained for the synchrotron x-ray source. A short summary of the present state of the synchrotron radiation-induced x-ray emission (SRIXE) method is presented here. Basically, SRIXE experiments can include any that depend on the detection. of characteristic x-rays produced by the incident x-ray beam born the synchrotron source as they interact with a sample. Thus, experiments done to measure elemental composition, chemical state, crystal, structure, and other sample parameters can be considered in a discussion of SRIXE. It is also clear that the experimentalist may well wish to use a variety of complementary techniques for study of a given sample. For this reason, discussion of computed microtomography (CMT) and x-ray diffraction is included here. It is hoped that this present discussion will serve as a succinct introduction to the basic ideas of SRIXE for those not working in the field and possibly help to stimulate new types of work by those starting in the field as well as by experienced practitioners of the art. The topics covered include short descriptions of (1) the properties of synchrotron radiation, (2) a description of facilities used for its production, (3) collimated microprobe, (4) focused microprobes, (5) continuum and monoenergetic excitation, (6) detection limits, (7) quantitation, (8) applications of SRIXE, (9) computed microtomography (CMT), and (10)chemical speciation using x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS). An effort has been made to cite a wide variety of work from different laboratories to show the vital nature of the field.

Jones, Keith W.

1999-09-01T23:59:59.000Z

60

Method and apparatus for enhanced sensitivity filmless medical x-ray imaging, including three-dimensional imaging  

DOE Patents (OSTI)

A filmless X-ray imaging system includes at least one X-ray source, upper and lower collimators, and a solid-state detector array, and can provide three-dimensional imaging capability. The X-ray source plane is distance z{sub 1} above upper collimator plane, distance z{sub 2} above the lower collimator plane, and distance z{sub 3} above the plane of the detector array. The object to be X-rayed is located between the upper and lower collimator planes. The upper and lower collimators and the detector array are moved horizontally with scanning velocities v{sub 1}, v{sub 2}, v{sub 3} proportional to z{sub 1}, z{sub 2} and z{sub 3}, respectively. The pattern and size of openings in the collimators, and between detector positions is proportional such that similar triangles are always defined relative to the location of the X-ray source. X-rays that pass through openings in the upper collimator will always pass through corresponding and similar openings in the lower collimator, and thence to a corresponding detector in the underlying detector array. Substantially 100% of the X-rays irradiating the object (and neither absorbed nor scattered) pass through the lower collimator openings and are detected, which promotes enhanced sensitivity. A computer system coordinates repositioning of the collimators and detector array, and X-ray source locations. The computer system can store detector array output, and can associate a known X-ray source location with detector array output data, to provide three-dimensional imaging. Detector output may be viewed instantly, stored digitally, and/or transmitted electronically for image viewing at a remote site. 5 figs.

Parker, S.

1995-10-24T23:59:59.000Z

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

X-ray lithography using holographic images  

DOE Patents (OSTI)

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

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

1995-01-01T23:59:59.000Z

62

Automation in X-Ray Crystallography  

Science Journals Connector (OSTI)

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

S.C. ABRAHAMS

1963-06-03T23:59:59.000Z

63

Chest x-Rays  

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

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

64

X-ray beamsplitter  

DOE Patents (OSTI)

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

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

1987-08-07T23:59:59.000Z

65

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

66

X-ray binaries  

E-Print Network (OSTI)

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

H. Schatz; K. E. Rehm

2006-08-01T23:59:59.000Z

67

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

Science Journals Connector (OSTI)

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

2014-01-01T23:59:59.000Z

68

Compound refractive X-ray lens  

DOE Patents (OSTI)

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

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

2000-01-01T23:59:59.000Z

69

X-ray laser  

DOE Patents (OSTI)

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

Nilsen, Joseph (Livermore, CA)

1991-01-01T23:59:59.000Z

70

Unorthodox theoretical methods  

SciTech Connect

The use of the ReaxFF force field to correlate with NMR mobilities of amine catalytic substituents on a mesoporous silica nanosphere surface is considered. The interfacing of the ReaxFF force field within the Surface Integrated Molecular Orbital/Molecular Mechanics (SIMOMM) method, in order to replicate earlier SIMOMM published data and to compare with the ReaxFF data, is discussed. The development of a new correlation consistent Composite Approach (ccCA) is presented, which incorporates the completely renormalized coupled cluster method with singles, doubles and non-iterative triples corrections towards the determination of heats of formations and reaction pathways which contain biradical species.

Nedd, Sean

2012-06-20T23:59:59.000Z

71

X-ray absorption spectroscopy  

E-Print Network (OSTI)

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

Yano, Junko; Yachandra, Vittal K.

2009-01-01T23:59:59.000Z

72

X-ray Absorption Spectroscopy  

E-Print Network (OSTI)

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

Yano, Junko

2010-01-01T23:59:59.000Z

73

X-Ray Generators  

Science Journals Connector (OSTI)

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

Reuben Rudman

1972-01-01T23:59:59.000Z

74

Location of Cu2+ in CHA zeolite investigated by X-ray diffraction using the Rietveld/maximum entropy method  

Science Journals Connector (OSTI)

Rietveld/MEM analysis applied to synchrotron powder X-ray diffraction data of dehydrated CHA zeolites with catalytically active Cu2+ reveals Cu2+ in both the six- and eight-membered rings in the CHA framework, providing the first complete structural model that accounts for all Cu2+. Density functional theory calculations are used to corroborate the experimental structure and to discuss the Cu2+ coordination in terms of the Al distribution in the framework.

Andersen, C.W.

2014-09-23T23:59:59.000Z

75

Quantitative Measurements of X-ray Intensity  

SciTech Connect

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

Haugh, M. J., Schneider, M.

2011-09-01T23:59:59.000Z

76

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

SciTech Connect

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

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

2011-07-15T23:59:59.000Z

77

X-ray beam finder  

DOE Patents (OSTI)

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

Gilbert, H.W.

1983-06-16T23:59:59.000Z

78

Method and apparatus for digitally based high speed x-ray spectrometer for direct coupled use with continuous discharge preamplifiers  

DOE Patents (OSTI)

A high speed, digitally based, signal processing system which accepts directly coupled input data from a detector with a continuous discharge type preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system's principal elements are an analog signal conditioning section, a combinatorial logic section which implements digital triangular filtering and pileup inspection, and a microprocessor which accepts values captured by the logic section and uses them to compute x-ray energy values. Operating without pole-zero correction, the system achieves high resolution by capturing, in conjunction with each peak value from the digital filter, an associated value of the unfiltered signal, and using this latter signal to correct the former for errors which arise from its local slope terms. This correction greatly reduces both energy resolution degradation and peak centroid shifting in the output spectrum as a function of input count rate. When the noise of this correction is excessive, a modification allows two filtered averages of the signal to be captured and a corrected peak amplitude computed therefrom.

Warburton, William K. (1300 Mills St., Menlo Park, CA 94025)

1998-01-01T23:59:59.000Z

79

Method and apparatus for digitally based high speed x-ray spectrometer for direct coupled use with continuous discharge preamplifiers  

DOE Patents (OSTI)

A high speed, digitally based, signal processing system is disclosed which accepts directly coupled input data from a detector with a continuous discharge type preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system`s principal elements are an analog signal conditioning section, a combinatorial logic section which implements digital triangular filtering and pileup inspection, and a microprocessor which accepts values captured by the logic section and uses them to compute x-ray energy values. Operating without pole-zero correction, the system achieves high resolution by capturing, in conjunction with each peak value from the digital filter, an associated value of the unfiltered signal, and using this latter signal to correct the former for errors which arise from its local slope terms. This correction greatly reduces both energy resolution degradation and peak centroid shifting in the output spectrum as a function of input count rate. When the noise of this correction is excessive, a modification allows two filtered averages of the signal to be captured and a corrected peak amplitude computed therefrom. 14 figs.

Warburton, W.K.

1998-06-30T23:59:59.000Z

80

A microfocus x-ray source based on a nonmetal liquid-jet anode  

SciTech Connect

We demonstrate stable operation of a nonmetallic anode in an electron-impact x-ray source. A high-brightness electron beam is focused on a {approx}70 m/s speed, {approx}10 {mu}m diameter methanol jet producing stable x-ray emission with peak spectral brightness at {approx}5.4x10{sup 5} photons/(sx{mu}m{sup 2}xsrx0.1%BW). The jet is fully evaporated in the interaction point. The shape of a simulated spectrum using Monte Carlo methods shows good agreement with experimental data, and the theoretical brightness values give an upper limit for the achievable x-ray emission from jets with very high velocities. Using this anode concept, all compounds and elements found in liquid form are potentially usable for x-ray generation.

Tuohimaa, T.; Ewald, J.; Schlie, M.; Hertz, H. M.; Vogt, U. [Biomedical and X-ray Physics, Department of Applied Physics, KTH Royal Institute of Technology/Albanova, SE-10691 Stockholm (Sweden); Fernandez-Varea, J. M. [Facultat de Fisica (ECM), Universitat de Barcelona, Diagonal 647, ES-08028 Barcelona (Spain)

2008-06-09T23:59:59.000Z

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

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

82

X-ray Spectrometry  

Science Journals Connector (OSTI)

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

Imre Szalóki; János Osán; René E. Van Grieken

2006-05-10T23:59:59.000Z

83

New Method of Assessing Absolute Permeability of Natural Methane Hydrate Sediments by Microfocus X-ray Computed Tomography  

Science Journals Connector (OSTI)

The structure of natural-gas hydrate sediments was studied using a microfocus X-ray computed-tomography (CT) system. The free-gas spaces, sand particles, and hydrates or ices were identified from the obtained three-dimensional (3-D) images. We used CT data to analyze a continuous pore, which allows gas and water flow. The absolute permeability of sediment samples correlated well with horizontal-channel density in terms of direction. The grain-size distribution in sediment samples depended on the spread of flow channels. The average area and length of a channel evidently have little effect on absolute permeability. We determined that absolute permeability increased with the ratio of horizontal- to vertical-channel numbers. It was clear that the number ratio of the horizontal to vertical channels is a predominant factor that determines absolute permeability in similar porosity ranges. These results indicate that the pore network in sediments can be useful for assessing permeability.

Yusuke Jin; Junko Hayashi; Jiro Nagao; Kiyofumi Suzuki; Hideki Minagawa; Takao Ebinuma; Hideo Narita

2007-01-01T23:59:59.000Z

84

Two dimensionally space-resolved electron temperature measurement of fusion plasma by x-ray monochromatic imaging method  

SciTech Connect

Electron temperature distributions of laser created fusion plasma were measured by using toroidally bent Bragg crystals. A tiny amount of argon was seeded in deuterium fuel gas and monochromatic images of Ar{sup +17} (1{ital s}{minus}3{ital p}) Ly{beta} and Ar{sup +16} (1{ital s}{sup 2}{minus}1{ital s}3{ital p}) He{beta} lines were taken to provide temperature distribution of the compressed core from their intensity ratios. A fusion core created by laser-generated x rays in a micro-cavity showed the temperature structure corresponding to the illumination asymmetry caused by the cavity irradiation geometry. The experimental distribution of the line-ratio of Ly{beta} to He{beta} was compared with the postprocessed outputs from one dimensional simulation, assuming perfect spherical implosion, to discuss degradation of pellet implosion. {copyright} {ital 1996 American Institute of Physics.}

Fujita, K.; Nishimura, H.; Uschmann, I.; Foerster, E.; Takabe, H.; Kato, Y.; Nakai, S. [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565 (Japan)

1996-05-01T23:59:59.000Z

85

3D printing in X-ray and gamma-ray imaging: A novel method for fabricating high-density imaging apertures  

Science Journals Connector (OSTI)

Advances in 3D rapid-prototyping printers, 3D modeling software, and casting techniques allow for cost-effective fabrication of custom components in gamma-ray and X-ray imaging systems. Applications extend to new fabrication methods for custom collimators, pinholes, calibration and resolution phantoms, mounting and shielding components, and imaging apertures. Details of the fabrication process for these components, specifically the 3D printing process, cold casting with a tungsten epoxy, and lost-wax casting in platinum are presented.

Brian W. Miller; Jared W. Moore; Harrison H. Barrett; Teresa Fryé; Steven Adler; Joe Sery; Lars R. Furenlid

2011-01-01T23:59:59.000Z

86

Oblique Soft X-Ray Tomography as a Non-Destructive Method for Morphology Diagnostics in Degradation of Proton-Exchange Membrane Fuel Cell  

Science Journals Connector (OSTI)

Abstract Diagnostics of performance degradation is important for improving the durability of proton-exchange membrane (PEM) fuel cells. X-ray computed tomography (CT) is a valuable non-destructive method to study the internal structure of PEM fuel cells. However, sample cutting is usually needed for high-resolution observations, which prevents the observer from obtaining information about morphology changes during fuel cell testing. In this study, oblique soft X-ray CT has been developed and its suitability as a non-destructive method for PEM fuel cell diagnostics without sample cutting is demonstrated. The CT images of a membrane-electrode assembly (MEA) were obtained at several stages of cell operation, including hot-pressing, load cycles, wet/dry cycles, and start-up/shutdown (SU/SD) experiments. After SU/SD operation, carbon corrosion with newly generated cracks was observed in the catalyst layer at the cathode outlet of the cell, while no corrosion was observed at the cathode inlet and center and at all anode-side positions. The size of cracks in the microporous layer, especially under the rib area, decreased after cell operation. This study validates that it is possible to observe the cause of fuel cell degradation, i.e., carbon corrosion, at a certain position of the MEA under several stages of operation, without cutting the MEA.

Phengxay Deevanhxay; Takashi Sasabe; Katsunori Minami; Shohji Tsushima; Shuichiro Hirai

2014-01-01T23:59:59.000Z

87

Cosmology with X-ray Cluster Baryons  

SciTech Connect

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

Linder, Eric V.

2007-04-10T23:59:59.000Z

88

Methods for assisting recovery of damaged brain and spinal cord and treating various diseases using arrays of x-ray microplanar beams  

DOE Patents (OSTI)

A method of assisting recovery of an injury site of the central nervous system (CNS) or treating a disease includes providing a therapeutic dose of X-ray radiation to a target volume through an array of parallel microplanar beams. The dose to treat CNS injury temporarily removes regeneration inhibitors from the irradiated site. Substantially unirradiated cells surviving between beams migrate to the in-beam portion and assist recovery. The dose may be staggered in fractions over sessions using angle-variable intersecting microbeam arrays (AVIMA). Additional doses are administered by varying the orientation of the beams. The method is enhanced by injecting stem cells into the injury site. One array or the AVIMA method is applied to ablate selected cells in a target volume associated with disease for palliative or curative effect. Atrial fibrillation is treated by irradiating the atrial wall to destroy myocardial cells while continuously rotating the subject.

Dilmanian, F. Avraham (Yaphank, NY); Anchel, David J. (Rocky Point, NY); Gaudette, Glenn (Holden, MA); Romanelli, Pantaleo (Monteroduni, IT); Hainfeld, James (Shoreham, NY)

2010-06-29T23:59:59.000Z

89

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.

90

X-ray Spectrometry  

Science Journals Connector (OSTI)

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

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

2002-05-18T23:59:59.000Z

91

A systematic periodicity and time-variable modulation search in RXTE ASM data : methods, findings, and implications for astrophysical X-ray sources  

E-Print Network (OSTI)

In this work, we present the results of a general search for periodicities and for time-variable modulation strength in X-ray sources using data from the All-Sky Monitor onboard the Rossi X-ray Timing Explorer. New findings, ...

Harris, Robert J., S.M. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

92

Speeding up the Raster Scanning Methods used in theX-Ray Fluorescence Imaging of the Ancient Greek Text of Archimedes  

SciTech Connect

Progress has been made at the Stanford Linear Accelerator Center (SLAC) toward deciphering the remaining 10-20% of ancient Greek text contained in the Archimedes palimpsest. The text is known to contain valuable works by the mathematician, including the ''Method of Mechanical Theorems, the Equilibrium of Planes, On Floating Bodies'', and several diagrams as well. The only surviving copy of the text was recycled into a prayer book in the Middle Ages. The ink used to write on the goat skin parchment is partly composed of iron, which is visible by x-ray radiation. To image the palimpsest pages, the parchment is framed and placed in a stage that moves according to the raster method. When an x-ray beam strikes the parchment, the iron in the ink is detected by a germanium detector. The resulting signal is converted to a gray-scale image on the imaging program, Rasplot. It is extremely important that each line of data is perfectly aligned with the line that came before it because the image is scanned in two directions. The objectives of this experiment were to determine the best parameters for producing well-aligned images and to reduce the scanning time. Imaging half a page of parchment during previous beam time for this project was achieved in thirty hours. Equations were produced to evaluate count time, shutter time, and the number of pixels in this experiment. On Beamline 6-2 at the Stanford Synchrotron Radiation Laboratory (SSRL), actual scanning time was reduced by one fourth. The remaining pages were successfully imaged and sent to ancient Greek experts for translation.

Turner, Manisha; /Norfolk State U.

2006-08-24T23:59:59.000Z

93

X-ray lithography using holographic images  

DOE Patents (OSTI)

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

Howells, M.S.; Jacobsen, C.

1997-03-18T23:59:59.000Z

94

X-ray lithography using holographic images  

DOE Patents (OSTI)

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

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

1997-01-01T23:59:59.000Z

95

X-ray fluorescence mapping  

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

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

96

Process and device for x-ray system quality assurance  

SciTech Connect

This invention relates to medical radiography test systems, and more particularly to a method and apparatus for providing evaluation of a medical or dental x-ray system consisting of x-ray generator, film and processor on a daily basis and to thereby assure the production of useful radiographs from the system with no need to repeat patient exposure because of problems with the x-ray system.

Van Pelt, W.F.; Peterson, R.W.

1982-11-10T23:59:59.000Z

97

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.

98

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.

99

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.

100

High-Resolution Soft X-Ray Spectral Analysis in the CK Region of Titanium Carbide (TiC) using the DV-X alpha Molecular Orbital Method  

E-Print Network (OSTI)

in the CK Region of Titanium Carbide (TiC) using the DV-X?USA Keyword titanium carbide, soft X-ray spectroscopy,C K region of titanium carbide (TiC). The spectral profiles

Shimomura, Kenta

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

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

Science Journals Connector (OSTI)

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

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

2002-05-01T23:59:59.000Z

102

Phase recovery for x-ray crystallography  

Science Journals Connector (OSTI)

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

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

1999-04-01T23:59:59.000Z

103

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

104

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

E-Print Network (OSTI)

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

Mauro Orlandini; Daniele Dal Fiume

2001-07-27T23:59:59.000Z

105

X-ray shearing interferometer  

DOE Patents (OSTI)

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

Koch, Jeffrey A. (Livermore, CA)

2003-07-08T23:59:59.000Z

106

Effects of {pi}-stacking interactions on the near carbon K-edge x-ray absorption fine structure: A theoretical study of the ethylene pentamer and the phthalocyanine dimer  

SciTech Connect

X-ray absorption spectra have been determined for ethylene and free base phthalocyanine at the carbon K-edge with use of the complex polarization propagator method combined with Kohn-Sham density functional theory and the Coulomb attenuated method B3LYP exchange-correlation functional. Apart from isolated molecules, the study includes {pi}-stacked systems of the phthalocyanine dimer and the ethylene dimer, trimer, tetramer, and pentamer. For ethylene, {pi}-stacking involves a reduction in transition energy of the valence {pi}*-band by some 70 meV and large spectral changes (regarding also shape and intensity) of the Rydberg bands. For phthalocyanine, there are large spectral changes in the entire valence {pi}*-part of the spectrum.

Linares, Mathieu; Stafstroem, Sven; Norman, Patrick [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden)

2009-03-14T23:59:59.000Z

107

The method of convergence to calculate particles fluxes in X rays spectrometry techniques. Application in nuclear compounds  

SciTech Connect

A method to calculate particle fluxes applicable in most of the spectroscopy techniques is described. Flux intensities of backscattered or absorbed electrons and emitted photons are calculated using a method of convergence to solve the invariant embedding equations that are used to describe the particle trajectories inside a solid sample. Our results are found to be helpful to carry out a procedure for quantitative characterization using instruments such as electron probe microanalyser or other probes. Examples of application to calculate the composition of ternary alloys are given and are compared with the same calculations using another procedure.

Figueroa, C.; Nieva, N.; Brizuela, H.; Heluani, S. P. [Laboratorio de Fisica del Solido, Dpto. de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman (Argentina)

2012-12-01T23:59:59.000Z

108

X-Ray Interactions with Matter from the Center for X-Ray Optics (CXRO)  

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.

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

109

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

SciTech Connect

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

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

2013-05-15T23:59:59.000Z

110

Analysis of the near-edge X-ray-absorption fine-structure of anthracene: A combined theoretical and experimental study  

SciTech Connect

The near-edge fine structure of the carbon K-edge absorption spectrum of anthracene was measured and theoretically analyzed by density functional theory calculations implemented in the StoBe code. It is demonstrated that the consideration of electronic relaxation of excited states around localized core holes yields a significant improvement of the calculated excitation energies and reproduces the experimentally observed fine structure well. The detailed analysis of excitation spectra calculated for each symmetry inequivalent excitation center allows in particular to examine the influence of chemical shifts and core hole effects on the excitation energies. Moreover, the visualization of final states explains the large variations in the oscillator strength of various transitions as well as the nature of Rydberg-states that exhibit a notable density of states below the ionization potentials.

Klues, Michael; Witte, Gregor, E-mail: gregor.witte@physik.uni-marburg.de [Molekulare Festkörperphysik, Philipps-Universität Marburg (Germany)] [Molekulare Festkörperphysik, Philipps-Universität Marburg (Germany); Hermann, Klaus, E-mail: hermann@FHI-Berlin.MPG.de [Inorganic Chemistry Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany)] [Inorganic Chemistry Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany)

2014-01-07T23:59:59.000Z

111

Spectral Formation in X-Ray Pulsars: Bulk Comptonization in the Accretion Shock  

Science Journals Connector (OSTI)

Accretion-powered X-ray pulsars are among the most luminous X-ray sources in the Galaxy. However, despite decades of theoretical and observational work since their discovery, no satisfactory model for the formation of the observed X-ray spectra has emerged. In particular, the previously available theories are unable to reproduce the power-law variation observed at high energies in many sources. In this paper we present the first self-consistent calculation of the spectrum emerging from a pulsar accretion column that includes an explicit treatment of the energization occurring in the shock. Using a rigorous eigenfunction expansion method based on the exact dynamical solution for the velocity profile in the column, we obtain a closed-form expression for the Green's function describing the upscattering of radiation injected into the column from a monochromatic source located at the top of the thermal mound, near the base of the flow. The Green's function is convolved with a Planck distribution to calculate the radiation spectrum resulting from the reprocessing of blackbody photons emitted by the thermal mound. We demonstrate that the energization of the photons in the shock naturally produces an X-ray spectrum with a power-law shape at high energies and a blackbody shape at low energies, in agreement with many observations of accreting X-ray pulsars.

Peter A. Becker; Michael T. Wolff

2005-01-01T23:59:59.000Z

112

Experimental investigation of the 100 keV X-ray dose response of the high-temperature thermoluminescence in LiF:Mg,Ti (TLD-100): theoretical interpretation using the unified interaction model  

Science Journals Connector (OSTI)

......measured from 1 to 50 000 Gy using 100 keV X rays at the European Synchroton Radiation Facility. Glow curves were deconvoluted into component...from 1 to 50,000 Gy using 100 keV X rays at the European Synchroton Radiation Facility. Glow curves were deconvoluted into component......

J. Livingstone; Y. S. Horowitz; L. Oster; H. Datz; M. Lerch; A. Rosenfeld; A. Horowitz

2010-03-01T23:59:59.000Z

113

Method and apparatus for combinatorial logic signal processor in a digitally based high speed x-ray spectrometer  

DOE Patents (OSTI)

A high speed, digitally based, signal processing system which accepts a digitized input signal and detects the presence of step-like pulses in the this data stream, extracts filtered estimates of their amplitudes, inspects for pulse pileup, and records input pulse rates and system livetime. The system has two parallel processing channels: a slow channel, which filters the data stream with a long time constant trapezoidal filter for good energy resolution; and a fast channel which filters the data stream with a short time constant trapezoidal filter, detects pulses, inspects for pileups, and captures peak values from the slow channel for good events. The presence of a simple digital interface allows the system to be easily integrated with a digital processor to produce accurate spectra at high count rates and allow all spectrometer functions to be fully automated. Because the method is digitally based, it allows pulses to be binned based on time related values, as well as on their amplitudes, if desired.

Warburton, William K. (1300 Mills St., Menlo Park, CA 94025); Zhou, Zhiquing (Carl) (Fremont, CA)

1999-01-01T23:59:59.000Z

114

Method and apparatus for combinatorial logic signal processor in a digitally based high speed x-ray spectrometer  

DOE Patents (OSTI)

A high speed, digitally based, signal processing system is disclosed which accepts a digitized input signal and detects the presence of step-like pulses in the this data stream, extracts filtered estimates of their amplitudes, inspects for pulse pileup, and records input pulse rates and system lifetime. The system has two parallel processing channels: a slow channel, which filters the data stream with a long time constant trapezoidal filter for good energy resolution; and a fast channel which filters the data stream with a short time constant trapezoidal filter, detects pulses, inspects for pileups, and captures peak values from the slow channel for good events. The presence of a simple digital interface allows the system to be easily integrated with a digital processor to produce accurate spectra at high count rates and allow all spectrometer functions to be fully automated. Because the method is digitally based, it allows pulses to be binned based on time related values, as well as on their amplitudes, if desired. 31 figs.

Warburton, W.K.

1999-02-16T23:59:59.000Z

115

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

Science Journals Connector (OSTI)

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

L. Pina; A. Inneman; R. Hudec

1996-01-01T23:59:59.000Z

116

Dynamic model of anisotropic x-ray refraction  

Science Journals Connector (OSTI)

General mechanisms of anisotropic x-ray refraction at the resonance energy are investigated on the basis of dynamic-scattering theory. The deductions show that x rays within the crystals that have anisotropic susceptibility are completely polarized and have two elliptical polarization states. Analytical expressions of the elliptical axes, refractive indices, and absorption coefficients for these two types of polarized waves are obtained in terms of the anisotropic components of the susceptibility tensor. Anisotropic birefringence and dichroism effects associated with the polarization properties of the x-ray waves are also illustrated theoretically.

X. R. Huang, Yong Li, W. J. Liu, and S. S. Jiang

1997-11-01T23:59:59.000Z

117

Opacity of iron, nickel, and copper plasmas in the x-ray wavelength range: Theoretical interpretation of 2p-3d absorption spectra  

SciTech Connect

This paper deals with theoretical studies on the 2p-3d absorption in iron, nickel, and copper plasmas related to LULI2000 (Laboratoire pour l'Utilisation des Lasers Intenses, 2000J facility) measurements in which target temperatures were of the order of 20 eV and plasma densities were in the range 0.004-0.01 g/cm{sup 3}. The radiatively heated targets were close to local thermodynamic equilibrium (LTE). The structure of 2p-3d transitions has been studied with the help of the statistical superconfiguration opacity code sco and with the fine-structure atomic physics codes hullac and fac. A new mixed version of the sco code allowing one to treat part of the configurations by detailed calculation based on the Cowan's code rcg has been also used in these comparisons. Special attention was paid to comparisons between theory and experiment concerning the term features which cannot be reproduced by sco. The differences in the spin-orbit splitting and the statistical (thermal) broadening of the 2p-3d transitions have been investigated as a function of the atomic number Z. It appears that at the conditions of the experiment the role of the term and configuration broadening was different in the three analyzed elements, this broadening being sensitive to the atomic number. Some effects of the temperature gradients and possible non-LTE effects have been studied with the help of the radiative-collisional code scric. The sensitivity of the 2p-3d structures with respect to temperature and density in medium-Z plasmas may be helpful for diagnostics of LTE plasmas especially in future experiments on the {Delta}n=0 absorption in medium-Z plasmas for astrophysical applications.

Blenski, T.; Loisel, G.; Poirier, M.; Thais, F.; Arnault, P.; Caillaud, T.; Fariaut, J.; Gilleron, F.; Pain, J.-C.; Porcherot, Q.; Reverdin, C.; Silvert, V.; Villette, B.; Bastiani-Ceccotti, S.; Turck-Chieze, S.; Foelsner, W.; Gaufridy de Dortan, F. de [CEA, IRAMIS, Service 'Photons, Atomes et Molecules', Centre d'Etudes de Saclay, F-91191 Gif-sur-Yvette Cedex (France); CEA, DAM, DIF, F-91297 Arpajon (France); LULI, UMR No. 7605 CNRS - Ecole Polytechnique, F-91128 Palaiseau Cedex (France); CEA, IRFU, Service d'Astrophysique, Centre d'Etudes de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Institute of Nuclear Fusion, Universidad Politecnica de Madrid, Spain and Laboratoire d'Optique Appliquee, ENSTA-Paritech-Polytechnique, Chemin de la Huniere, F-91671 Palaiseau (France)

2011-09-15T23:59:59.000Z

118

SMB, X-Ray Spectroscopy & Imaging  

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

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

119

Lensless X-Ray Imaging in Reflection  

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

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

120

X-ray lasers and methods utilizing two component driving illumination provided by optical laser means of relatively low energy and small physical size  

DOE Patents (OSTI)

An X-ray laser (10), and related methodology, are disclosed wherein an X-ray laser target (12) is illuminated with a first pulse of optical laser radiation (14) of relatively long duration having scarcely enough energy to produce a narrow and linear cool plasma of uniform composition (38). A second, relatively short pulse of optical laser radiation (18) is uniformly swept across the length, from end to end, of the plasma (38), at about the speed of light, to consecutively illuminate continuously succeeding portions of the plasma (38) with optical laser radiation having scarcely enough energy to heat, ionize, and invert them into the continuously succeeding portions of an X-ray gain medium. This inventive double pulse technique results in a saving of more than two orders of magnitude in driving optical laser energy, when compared to the conventional single pulse approach.

Rosen, Mordecai D. (Berkeley, CA); Matthews, Dennis L. (El Granada, CA)

1991-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "theoretical methods x-ray" 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 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.

122

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

123

Center for X-Ray Optics, 1992  

SciTech Connect

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

Not Available

1993-08-01T23:59:59.000Z

124

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

E-Print Network (OSTI)

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

Wolfe, Patrick J.

125

Multiple wavelength X-ray monochromators  

DOE Patents (OSTI)

An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focusing the separate first and second output x-ray radiation wavelengths into separate focal points. 3 figs.

Steinmeyer, P.A.

1992-11-17T23:59:59.000Z

126

Center for X-Ray Optics, 1991  

SciTech Connect

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

Not Available

1992-03-01T23:59:59.000Z

127

SMB, X-ray Absorption Spectroscopy  

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

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

128

Maximum Entropy Method and Charge Flipping, a Powerful Combination to Visualize the True Nature of Structural Disorder from in situ X-ray Powder Diffraction Data  

SciTech Connect

In a systematic approach, the ability of the Maximum Entropy Method (MEM) to reconstruct the most probable electron density of highly disordered crystal structures from X-ray powder diffraction data was evaluated. As a case study, the ambient temperature crystal structures of disordered {alpha}-Rb{sub 2}[C{sub 2}O{sub 4}] and {alpha}-Rb{sub 2}[CO{sub 3}] and ordered {delta}-K{sub 2}[C{sub 2}O{sub 4}] were investigated in detail with the aim of revealing the 'true' nature of the apparent disorder. Different combinations of F (based on phased structure factors) and G constraints (based on structure-factor amplitudes) from different sources were applied in MEM calculations. In particular, a new combination of the MEM with the recently developed charge-flipping algorithm with histogram matching for powder diffraction data (pCF) was successfully introduced to avoid the inevitable bias of the phases of the structure-factor amplitudes by the Rietveld model. Completely ab initio electron-density distributions have been obtained with the MEM applied to a combination of structure-factor amplitudes from Le Bail fits with phases derived from pCF. All features of the crystal structures, in particular the disorder of the oxalate and carbonate anions, and the displacements of the cations, are clearly obtained. This approach bears the potential of a fast method of electron-density determination, even for highly disordered materials. All the MEM maps obtained in this work were compared with the MEM map derived from the best Rietveld refined model. In general, the phased observed structure factors obtained from Rietveld refinement (applying F and G constraints) were found to give the closest description of the experimental data and thus lead to the most accurate image of the actual disorder.

Samy, A.; Dinnebier, R; van Smaalen, S; Jansen, M

2010-01-01T23:59:59.000Z

129

High-Resolution Soft X-Ray Spectral Analysis in the CK Region of Titanium Carbide (TiC) using the DV-X alpha Molecular Orbital Method  

E-Print Network (OSTI)

1 XRD pattern of the measured TiC powder sample. Figure 2XAS. Intensity (arb. units) TiC X-ray: Cu K? voltage: 40 kVintensity (arb. units) CK-XES TiC b a c HOPG e f CK-XAS TiC

Shimomura, Kenta

2010-01-01T23:59:59.000Z

130

Triple-Energy X-Ray Absorptiometry for Determination of the Bone Mineral Content in Vivo  

Science Journals Connector (OSTI)

Dual-energy X-ray absorptiometry (DXA) is a ... method for the determination of the bone mineral content in vivo. It has a high precision ... bone. The present work describes a triple-energy X-ray absorptiometry ...

Janos Szücs; Ragnar Jonson; Tommy Hansson

1993-01-01T23:59:59.000Z

131

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

132

Soft-X-Ray-Charged Vertical Electrets and Its Application to Electrostatic Transducers  

E-Print Network (OSTI)

Soft-X-Ray-Charged Vertical Electrets and Its Application to Electrostatic Transducers Makoto A novel charging method for vertical electrets in narrow gaps using soft X-rays has been developed is necessary after charging the electrets. Recently, we have developed a new charging method using soft X-ray

Kasagi, Nobuhide

133

X-ray Emission from Massive Stars  

E-Print Network (OSTI)

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

Cohen, David

134

X-ray Emission from Massive Stars  

E-Print Network (OSTI)

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

Cohen, David

135

Crystallization and shear modulus of a forming biopolymer film determined by in situ x-ray diffraction and ultrasound reflection methods  

Science Journals Connector (OSTI)

The structure and the rigidity of a forming biopolymer film were determined using concurrent x-ray diffraction and ultrasonic reflection measurements. Film formation of a xylan solution (de-ionized water 10 g ? l xylan 4 g ? l glycerol) was studied during water evaporation at 24 ( ± 2 ) ° C 37 ( ± 5 ) % RH . X-ray diffraction(XRD) data showed the crystallization and ultrasonic data the increase of the shear modulus ( G ) during water evaporation. Xylan crystallized into small xylan dihydrate crystallites the number of which increased as water evaporated. Crystallization began earlier than the increase in G during film formation. The increase in G also continued after the crystallites were fully formed indicating still ongoing structural changes in the amorphous parts. The maximum value of G was 0.1 – 0.5 GPa . XRD measurements performed ex situ showed a crystallinity of 16%–19% ( ± 5 % ) and a fairly isotropic crystallite orientation in the surface plane of the films.

Marko Peura; Timo Karppinen; Annemai Soovre; Ari Salmi; Maija Tenkanen; Edward Hæggström; Ritva Serimaa

2008-01-01T23:59:59.000Z

136

Compact x-ray source and panel  

DOE Patents (OSTI)

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

Sampayon, Stephen E. (Manteca, CA)

2008-02-12T23:59:59.000Z

137

Plasma X-ray Spectra Analysis Using Genetic Algorithms Igor E. Golovkin  

E-Print Network (OSTI)

Plasma X-ray Spectra Analysis Using Genetic Algorithms Igor E. Golovkin Department of Physics for plasma diagnostics. We use genetic algorithms to automatically analyze experi- mental X-ray line spectra-ray line spectra. 1 INTRODUCTION X-ray spectroscopic analysis is a widely used method for hot dense plasma

Louis, Sushil J.

138

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-Print Network (OSTI)

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPPOWGAD data collection on the Bruker GADDS Powder X-ray Diffractometer. POLICY: Data must be collected AND PRECAUTIONS 1. Powder X-ray diffraction is a method by which investigators can identify the materials

Meagher, Mary

139

X-ray Fluorescence Measurements of Manganese in Petroglyphs and Graffiti in the Bluff, Utah Area  

E-Print Network (OSTI)

X-ray Fluorescence Measurements of Manganese in Petroglyphs and Graffiti in the Bluff, Utah Area the age of rock art using Mn levels, Lytle (2008). In this work we use x-ray fluorescence (XRF) to measure of methods including atomic mass spectroscopy (AMS) measurements of 14 C, Particle-induced X-ray Excitation

140

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-Print Network (OSTI)

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPDATGAD to facilitate data collection on the Bruker GADDS Single-crystal X-ray Diffractometer. POLICY: Data must. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which investigators can

Meagher, Mary

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

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,

142

X-ray radiography for container inspection  

DOE Patents (OSTI)

Arrangements of X-ray inspection systems are described for inspecting high-z materials in voluminous objects such as containers. Inspection methods may involve generating a radiographic image based on detected attenuation corresponding to a pulsed beams of radiation transmitted through a voluminous object. The pulsed beams of radiation are generated by a high-energy source and transmitted substantially downward along an incident angle, of approximately 1.degree. to 30.degree., to a vertical axis extending through the voluminous object. The generated radiographic image may be analyzed to detect on localized high attenuation representative of high-z materials and to discriminate high-z materials from lower and intermediate-z materials on the basis of the high density and greater attenuation of high-z material for higher energy (3-10 MeV) X-rays, and the compact nature of threatening masses of fissionable materials.

Katz, Jonathan I. (Clayton, MO); Morris, Christopher L. (Los Alamos, NM)

2011-06-07T23:59:59.000Z

143

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

E-Print Network (OSTI)

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

Guo, Ting

144

Measurements of the hard-x-ray reflectivity of iridium  

SciTech Connect

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

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

2007-01-10T23:59:59.000Z

145

Characterization of X-ray generator beam profiles.  

SciTech Connect

T to compute the radiography properties of various materials, the flux profiles of X-ray sources must be characterized. This report describes the characterization of X-ray beam profiles from a Kimtron industrial 450 kVp radiography system with a Comet MXC-45 HP/11 bipolar oil-cooled X-ray tube. The empirical method described here uses a detector response function to derive photon flux profiles based on data collected with a small cadmium telluride detector. The flux profiles are then reduced to a simple parametric form that enables computation of beam profiles for arbitrary accelerator energies.

Mitchell, Dean J; Harding, Lee T.; Thoreson, Gregory G.; Theisen, Lisa Anne; Parmeter, John Ethan; Thompson, Kyle Richard

2013-07-01T23:59:59.000Z

146

Focused X-ray source  

DOE Patents (OSTI)

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

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

1990-08-21T23:59:59.000Z

147

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.

148

X-ray Phase Contrast analysis - Digital wavefront development  

SciTech Connect

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

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

2010-06-23T23:59:59.000Z

149

X-Ray Diffraction Studies of Copper Nanopowder  

E-Print Network (OSTI)

Copper nanopowder preparation and its X-Ray diffraction studies are reported in this paper. Electrolytic cathode deposition method is simple and cheapest process for its preparation. Copper nanopowder has been prepared from aqueous copper sulphate solution. Wide range of experimental conditions has been adopted in this process and its X-Ray diffraction characterizations have been studied. The results confirming copper nanopowder with size below 30 nm. Uniformed size Copper nanopowder preparation, in normal room temperature is importance of this study.

T. Theivasanthi; M. Alagar

2010-03-31T23:59:59.000Z

150

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

151

Lensless X-Ray Imaging in Reflection  

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

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

152

Lensless X-Ray Imaging in Reflection  

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

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

153

Producing X-rays at the APS  

ScienceCinema (OSTI)

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

None

2013-04-19T23:59:59.000Z

154

SMB, X-ray Fluorescence Imaging  

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

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

155

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

156

Magnetic fields of neutron stars in X-ray binaries  

E-Print Network (OSTI)

A substantial fraction of the known neutron stars resides in X-ray binaries -- systems in which one compact object accretes matter from a companion star. Neutron stars in X-ray binaries have magnetic fields among the highest found in the Universe, spanning at least the range from $\\sim10^8$ to several 10$^{13}$ G. The magnetospheres around these neutron stars have a strong influence on the accretion process, which powers most of their emission. The magnetic field intensity and geometry, are among the main factors responsible for the large variety of spectral and timing properties observed in the X-ray energy range, making these objects unique laboratories to study the matter behavior and the radiation processes in magnetic fields unaccessible on Earth. In this paper we review the main observational aspects related to the presence of magnetic fields in neutron star X-ray binaries and some methods that are used to estimate their strength.

Revnivtsev, Mikhail

2014-01-01T23:59:59.000Z

157

Gravitational and Relativistic Deflection of X-Ray Superradiance  

E-Print Network (OSTI)

Exploring Einstein's theories of relativity in quantum systems, for example by using atomic clocks at high speeds can deepen our knowledge in physics. However, many challenges still remain on finding novel methods for detecting effects of gravity and of special relativity and their roles in light-matter interaction. Here we introduce a scheme of x-ray quantum optics that allows for a millimeter scale investigation of the relativistic redshift by directly probing a fixed nuclear crystal in Earth's gravitational field with x-rays. Alternatively, a compact rotating crystal can be used to force interacting x-rays to experience inhomogeneous clock tick rates in a crystal. We find that an association of gravitational or special-relativistic time dilation with quantum interference will be manifested by deflections of x-ray photons. Our protocol suggests a new and feasible tabletop solution for probing effects of gravity and special relativity in the quantum world.

Wen-Te Liao; Sven Ahrens

2014-11-27T23:59:59.000Z

158

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

159

Chandra X-ray Observatory Center  

E-Print Network (OSTI)

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

160

X-Ray Absorption Spectroscopy of Metallobiomolecules  

E-Print Network (OSTI)

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

Scott, Robert A.

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

Chandra X-ray Observatory Center  

E-Print Network (OSTI)

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

162

X-ray Spectroscopy of Cool Stars  

E-Print Network (OSTI)

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

M. Guedel

2006-09-11T23:59:59.000Z

163

X-Ray Physics Evan Berkowitz  

E-Print Network (OSTI)

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

164

Chandra X-ray Observatory Center  

E-Print Network (OSTI)

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

165

X-Ray Absorption Spectroscopy of Metallobiomolecules  

E-Print Network (OSTI)

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

Scott, Robert A.

166

Chandra X-ray Observatory Center  

E-Print Network (OSTI)

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

167

Using Light to Control How X Rays Interact with Matter  

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

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

168

Time dependence of X-ray polarizability of a crystal induced by an intense femtosecond X-ray pulse  

Science Journals Connector (OSTI)

The time evolution of the electron density and the resulting time dependence of the X-ray polarizability of a crystal irradiated by highly intense XFEL femtosecond pulses is investigated theoretically. Rate equations for bound electrons and the Boltzmann equation for the unbound electron gas are used in calculations.

Leonov, A.

2014-10-23T23:59:59.000Z

169

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.

170

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.

171

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

E-Print Network (OSTI)

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

P. C. Schmidtke; A. P. Cowley

2005-09-28T23:59:59.000Z

172

Tunable sub-luminal propagation of narrowband x-ray pulses  

E-Print Network (OSTI)

Group velocity control is demonstrated for x-ray photons of 14.4 keV energy via a direct measurement of the temporal delay imposed on spectrally narrow x-ray pulses. Sub-luminal light propagation is achieved by inducing a steep positive linear dispersion in the optical response of ${}^{57}$Fe M\\"ossbauer nuclei embedded in a thin film planar x-ray cavity. The direct detection of the temporal pulse delay is enabled by generating frequency-tunable spectrally narrow x-ray pulses from broadband pulsed synchrotron radiation. Our theoretical model is in good agreement with the experimental data.

K. P. Heeg; J. Haber; D. Schumacher; L. Bocklage; H. -C. Wille; K. S. Schulze; R. Loetzsch; I. Uschmann; G. G. Paulus; R. Rüffer; R. Röhlsberger; J. Evers

2014-09-01T23:59:59.000Z

173

Intravenous coronary angiography utilizing K-emission and bremsstrahlung X-rays produced by electron bombardment  

SciTech Connect

The screening of the general population for coronary artery disease would be practical if a method existed for visualizing the extent of occlusion after an intravenous injection of contrast agent. Measurements performed with synchrotron radiation at SSRL and NSLS have shown that such an intravenous angiography procedure would be possible with an intense source of monochromatic X-rays. Because of the high cost of an electron synchrotron, theoretical analysis and experiments using inanimate phantoms has been undertaken to demonstrate the feasibility of using the spectrum produced by two appropriately chosen anode materials when bombarded with electrons in the 100--500 keV energy range for angiography. By using the X-rays emitted at 120{degree} to the incident electron direction, about 20--30% of the X-ray intensity would be due to K-emission lines. Calculations using the TIGERP Monte Carlo Code, have shown that high quality angiograms of human coronary arteries should be possible with a contrast agent containing ytterbium, if an electron beam pulses of 16 kJ were used for each anode target. The experimental program supported in part by the DOE has consisted of these theoretical calculations and experiments at the Dynamitron Electron Accelerator Facility at BNL.

NONE

1992-12-31T23:59:59.000Z

174

K?K? X-Ray Transition-Probability Ratios for Elements 18?Z?39  

Science Journals Connector (OSTI)

K?K? x-ray transition-probability ratios for 16 elements in the range 18?Z?39 were measured with a high-resolution Si(Li) detector. The K vacancies were produced by a heavily filtered bremsstrahlung beam from a commercial x-ray tube. Our results agree qualitatively with the theoretical calculations of Scofield but are consistently about 15% higher.

V. W. Slivinsky and P. J. Ebert

1972-04-01T23:59:59.000Z

175

X-ray Spectroscopy of Cooling Cluster  

SciTech Connect

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

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

2006-01-17T23:59:59.000Z

176

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

177

X-ray Spectroscopy of Cooling Clusters  

E-Print Network (OSTI)

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

J. R. Peterson; A. C. Fabian

2005-12-21T23:59:59.000Z

178

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

179

The History of X-ray Free-Electron Lasers  

SciTech Connect

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

180

13 - X-ray and Neutron Scattering  

Science Journals Connector (OSTI)

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

Gernot Kostorz

2014-01-01T23:59:59.000Z

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


181

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

SciTech Connect

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

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

2013-09-23T23:59:59.000Z

182

X-ray Observations of Mrk 231  

E-Print Network (OSTI)

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

T. J. Turner

1998-08-10T23:59:59.000Z

183

Measurement by x-ray diffraction methods of the layer compressional elastic constant B in the lyotropic smectic-A (L?) phase of the lecithin-water system  

Science Journals Connector (OSTI)

A high-resolution synchrotron x-ray study of oriented, supported, hydrated dilauryl phosphatidylcholine in the lyotropic L? (smectic-A or ‘‘fluid’’) phase shows that thermal fluctuations give rise to algebraic decay of positional order in stacking of the bimolecular lamellae, the so-called ‘‘Landau-Peierls’’ state. For planar monocrystalline samples of thickness 10–20 ?m, the exponents derived from intensity profiles are in accord with harmonic theory. When combined with previous measurements of the splay elastic constant K in this lyotropic system, the exponents indicate a bulk compressional elastic constant B=(1.9±1.0)×108 erg/cm3, consistent in magnitude with values measured in thermotropic liquid crystals. Samples of thickness ?1–2 ?m show anomalous behavior in the wings of the longitudinal intensity profiles, but are not in accord with harmonic theory, suggesting that surface effects partially quench the thermal fluctuations. Grandjean terraces on sample surfaces produce striking refractive effects at low Bragg angles.

Daniel C. Wack and Watt W. Webb

1989-08-01T23:59:59.000Z

184

Hard x-ray imaging from explorer  

SciTech Connect

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

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

1981-11-01T23:59:59.000Z

185

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

Science Journals Connector (OSTI)

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

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

2000-01-01T23:59:59.000Z

186

Applications of soft x-ray lasers  

SciTech Connect

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

Skinner, C.H.

1993-08-01T23:59:59.000Z

187

High speed x-ray beam chopper  

DOE Patents (OSTI)

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

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

2002-01-01T23:59:59.000Z

188

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

E-Print Network (OSTI)

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

Kaplan, Alexander

189

Colloid Coalescence with Focused X Rays  

SciTech Connect

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

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

2011-07-01T23:59:59.000Z

190

X-RAY MICROBEAM SPEECH PRODUCTION DATABASE  

E-Print Network (OSTI)

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

191

X-ray laser microscope apparatus  

DOE Patents (OSTI)

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

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

1990-01-01T23:59:59.000Z

192

X-Ray Laser Sources for Microscopy  

Science Journals Connector (OSTI)

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

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

1988-01-01T23:59:59.000Z

193

X-Ray Science Division (XSD)  

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

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

194

Development of a coincidence system for the measurement of X-ray emission atomic parameters  

SciTech Connect

Preliminary results obtained in experiments carried out with an x-ray spectrometer built at the Instituto de Fisica for Atomic Physics and environmental sciences studies are presented. The experiments are based on a coincidence method for signals produced by LEGe and Si(Li) detectors. The x-ray fluorescence yields ({omega}{sub Li}) and Coster-Kronig transition probabilities (f{sub ij}) for elements with 55 {<=} Z {<=} 60 are among the quantities of interest. The method is based on the simultaneous detection of K x-rays with the LEGe detector and the L x-rays with the Si(Li) detector. The primary radiation source is an x-ray tube with Rh anode. The system was tested with the coincidence of the L x-rays from Ce with its K line, demonstrating the feasibility of the experiments.

Martinez, Filiberto; Miranda, Javier [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000 Mexico, D.F (Mexico)

2013-07-03T23:59:59.000Z

195

High-Energy Diffraction-Enhanced X-ray Imaging  

SciTech Connect

In order to apply the diffraction-enhanced X-ray imaging (DEI) method for much wider variety of samples, we have developed the high-energy DEI system. The energy of X-ray was increased up to 70 keV to achieve high permeability for heavy elements. The diffraction of Si(440) was used to keep large field of view. Demonstrative observation of an electrical cable was performed using the X-ray emitted from the vertical wiggler. The obtained images visualized not only the core and ground wire made of copper but also the isolator and outer jacket made of polymer clearly. The comparison of images obtained by the DEI and the absorption-contrast imaging showed that the sensitivity of DEI is about 10 times higher than that of the absorption method for light elements, and 3 times for heavy elements.

Yoneyama, Akio; Ueda, Kazuhiro [Advanced Research Laboratory, Hitachi Ltd., 2520, Akanuma, Hatoyama, Saitama, 350-0395 (Japan); Takeda, Tohoru [Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa 228-8555 (Japan); Yamazaki, Takanori [Research and Development Laboratory, Hitachi Cable, Ltd., 5-1-1, Hidakacho, Hitachi, Ibaraki, 319-1414 (Japan); Hyodo, Kazuyuki [Institute of Materials Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan)

2010-06-23T23:59:59.000Z

196

Magnetic x-ray scattering at the M{sub 5} absorption edge of Ho  

SciTech Connect

Magnetic x-ray scattering from thin Ho-metal films at M{sub 5} resonance reveals atomic scattering lengths up to 200r{sub 0}--i.e., of the same order of magnitude as predicted theoretically by Hannon et al. [Phys. Rev. Lett. 61, 1245 (1988)]. The photon-energy dependence of first- and second-order magnetic satellites allows a straightforward identification of circular and linear dichroic contributions. A direct comparison to magnetic neutron scattering demonstrates the potential of the method for studies of complex magnetic structures in ultrathin films and highly diluted materials.

Ott, H.; Schierle, E.; Grigoriev, A. Yu.; Kaindl, G.; Weschke, E. [Institut fuer Experimentalphysik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin-Dahlem (Germany); Schuessler-Langeheine, C. [Institut fuer Experimentalphysik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin-Dahlem (Germany); II. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Leiner, V. [Institut fuer Experimentalphysik/Festkoerperphysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Institut fuer Werkstoffforschung, WFN, GKSS Forschungszentrum, D-21502 Geesthacht (Germany); Zabel, H. [Institut fuer Experimentalphysik/Festkoerperphysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2006-09-01T23:59:59.000Z

197

Workshop report on new directions in soft x-ray photoabsorption  

SciTech Connect

The Workshop Report integrates what was said at the Workshop on New Directions in Soft X-Ray Photoabsorption, which focused on the region from 100 eV to 10 keV. The report clarifies the current state of theory and experiment and identifies the opportunities which new theoretical methods and experimental facilities could be expected to provide. The understanding of photoabsorption (which requires experimental photoabsorption cross section data) is a key to understanding the properties and behavior of atoms, molecules and solids. The Workshop participants were forty-three physicists and quantum chemists, from twenty-four institutions in four countries, all interested in photoabsorption from different perspectives.

Bartlett, R.; Del Grande, N.K.; Lindau, I.; Manson, S.; Merts, A.L.; Pratt, R.

1984-09-17T23:59:59.000Z

198

Characterization of GaSb/GaAs interfacial misfit arrays using x-ray diffraction  

Science Journals Connector (OSTI)

We report a nondestructive large-area method to characterize dislocation formation at a highly lattice-mismatched interface. The analysis is based on x-ray diffraction and reciprocal space mapping using a standard lab-based diffractometer. We use this technique to identify and analyze a two-dimensional array of 90° misfit dislocations at a GaSb/GaAs interface. The full width at half maximum of the GaSb 004 reciprocal lattice point is shown to decrease with increasing GaSb epilayer thickness as expected from theoretical models. Based on these measurements the variation in the spatial dislocation frequency is calculated to be 1%.

Charles J. Reyner; Jin Wang; Kalyan Nunna; Andrew Lin; Baolai Liang; Mark S. Goorsky; D. L. Huffaker

2011-01-01T23:59:59.000Z

199

Standoff detection of hidden objects using backscattered ultra-intense laser-produced x-rays  

SciTech Connect

Ultra-intense laser-produced sub-ps X-ray pulses can detect backscattered signals from objects hidden in aluminium containers. Coincident measurements using primary X-rays enable differentiation among acrylic, copper, and lead blocks inside the container. Backscattering reveals the shapes of the objects, while their material composition can be identified from the modification methods of the energy spectra of backscattered X-ray beams. This achievement is an important step toward more effective homeland security.

Kuwabara, H. [IHI Corporation, 1, Shin-Nakahara-cho, Isogo-ku, Yokohama 235-8501 (Japan)] [IHI Corporation, 1, Shin-Nakahara-cho, Isogo-ku, Yokohama 235-8501 (Japan); Mori, Y.; Kitagawa, Y. [The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsucho, Nishiku, Hamamatsu, Shizuoka 431-1202 (Japan)] [The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsucho, Nishiku, Hamamatsu, Shizuoka 431-1202 (Japan)

2013-08-28T23:59:59.000Z

200

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

SciTech Connect

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

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

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "theoretical methods x-ray" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


201

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

202

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

E-Print Network (OSTI)

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

Â?umer, Slobodan

203

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

E-Print Network (OSTI)

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

Moeck, Peter

204

Quantum coherence in the dynamical excitation, ionization, and decaying of neon gas induced by X-ray laser  

E-Print Network (OSTI)

We develop a large scale quantum master equation approach to describe dynamical processes of practical open quantum systems driven by both coherent and stochastic interactions by including more than one thousand true states of the systems, motivated by the development of highly bright and fully coherent lasers in the X-ray wavelength regime. The method combines the processes of coherent dynamics induced by the X-ray laser and incoherent relaxations due to spontaneous emissions, Auger decays, and electronic collisions. As examples, theoretical investigation of {\\it real} coherent dynamics of inner-shell electrons of a neon gas, irradiated by a high-intensity X-ray laser with a full temporal coherence, is carried out with the approach. In contrast to the rate equation treatment, we find that coherence can suppress the multiphoton absorptions of a neon gas in the ultra-intense X-ray pulse, due to coherence-induced Rabi oscillations and power broadening effects. We study the influence of coherence on ionization p...

Li, Yongqiang; Dong, Wenpu; Zeng, Jiaolong; Yuan, Jianmin

2015-01-01T23:59:59.000Z

205

X-ray spectroscopy in mammography with a silicon PIN photodiode with application to the measurement of tube voltage  

SciTech Connect

In this work a silicon PIN photodiode was employed in mammographic x-ray spectroscopy under clinical and nonclinical conditions. Measurements have been performed at a constant potential tungsten anode tube, adapted in this work with molybdenum filters to produce a beam like that used in mammography, and at a clinical equipment with a molybdenum anode tube by using an additional aluminum filtration. The corrected x-ray spectra were in full agreement with those generated by theoretical models published in the literature and agree well with those measured with a CdZnTe detector for tube voltages less than 30 kV. The half value layer and the relative exposure values calculated from the corrected silicon PIN photodiode spectra were in agreement with those measured with an ionization chamber. These results indicate that a silicon PIN photodiode are very suitable for mammographic x-ray spectroscopy. As an application, the voltage (kV) applied to mammographic x-ray equipment has been measured through the evaluation of the spectra high energy cut off. Uncertainties evaluated for the voltage values calculated from the measured spectra are less than 0.13% for voltages in the range 20-35 kV. The low uncertainties associated with the obtained results in this work point out that the method employed can be accurately used for calibration of noninvasive mammographic kVp meters.

Kuenzel, Roseli; Herdade, Silvio Bruni; Terini, Ricardo Andrade; Costa, Paulo Roberto [Instituto de Fisica, Universidade de Sao Paulo, Rua do Matao, Travessa R, 187, Cidade Universitaria, CEP 05508-900, Sao Paulo, Sao Paulo (Brazil); Departamento de Fisica, Pontificia Universidade Catolica de Sao Paulo, R. Marques de Paranagua, 111, Consolacao, CEP 01303-050, Sao Paulo, Sao Paulo (Brazil); Secao Tecnica de Desenvolvimento Tecnologico em Saude, Instituto de Electrotecnica e Energia, Universidade de Sao Paulo, Avenida Professor Luciano Gualberto, 1289, Cidade Universitaria, CEP 05508-010, Sao Paulo (Brazil)

2004-11-01T23:59:59.000Z

206

Thermonuclear (Type I) X-Ray Bursts Observed by the Rossi X-Ray Timing Explorer  

Science Journals Connector (OSTI)

We have assembled a sample of 1187 thermonuclear (type I) X-ray bursts from observations of 48 accreting neutron stars by the Rossi X-ray Timing Explorer, spanning more than 10 years. The sample contains examples of two of the three theoretical ignition regimes (confirmed via comparisons with numerical models) and likely examples of the third. We present a detailed analysis of the variation of the burst profiles, energetics, recurrence times, presence of photospheric radius expansion, and presence of burst oscillations, as a function of accretion rate. We estimated the distance for 35 sources exhibiting radius-expansion bursts, and found that the peak flux of such bursts varies typically by 13%. We classified sources into two main groups based on the burst properties: (1) both long and short bursts (indicating mixed H/He accretion), and (2) consistently short bursts (primarily He accretion), and we calculated the mean burst rate as a function of accretion rate for the two groups. The decrease in burst rate observed at > 0.06Edd$0.06˙{M}Edd$ --> ( -->2 ? 1037 ergs s?1) is associated with a transition in the persistent spectral state and (as has been suggested previously) may be related to the increasing role of steady He burning. We found many examples of bursts with recurrence times

Duncan K. Galloway; Michael P. Muno; Jacob M. Hartman; Dimitrios Psaltis; Deepto Chakrabarty

2008-01-01T23:59:59.000Z

207

X-rays at Solid-Liquid Surfaces  

SciTech Connect

Solid-liquid interfaces play an important role in many areas of current and future technologies, and in our biosphere. They play a key role in the development of nanofluidics and nanotribology, which sensitively depend on our knowledge of the microscopic structures and phenomena at the solid-liquid interface. The detailed understanding of how a fluid meets a wall is also a theoretical challenge. In particular, the phenomena at repulsive walls are of interest, since they affect many different phenomena, such as water-repellent surfaces or the role of the hydrophobic interaction in protein folding. Recent x-ray reflectivity studies of various solid-liquid interfaces have disclosed rather intriguiing phenomena, which will be discussed in this lecture: premelting of ice in contact with silica; liquid Pb in contact with Si; water in contact with hydrophobic surfaces. These experiments, carried out with high-energy x-ray microbeams, reveal detailed insight into the liquid density profile closest to the wall. A detailed insight into atomistic phenomena at solid-liquid interfaces is also a prerequisite in the microscopic control of electrochemical reactions at interfaces. Recent x-ray studies show the enormous future potential of such non-destructive analytical tools for the in situ observation of (electro-)chemical surface reactions. This lecture will review recent x-ray experiments on solid-liquid interfaces.

Dosch, Helmut (Max Planck Institute for Metals Research) [Max Planck Institute for Metals Research

2007-05-02T23:59:59.000Z

208

Cooling for a rotating anode X-ray tube  

DOE Patents (OSTI)

A method and apparatus for cooling a rotating anode X-ray tube. An electromagnetic motor is provided to rotate an X-ray anode with cooling passages in the anode. These cooling passages are coupled to a cooling structure located adjacent the electromagnetic motor. A liquid metal fills the passages of the cooling structure and electrical power is provided to the motor to rotate the anode and generate a rotating magnetic field which moves the liquid metal through the cooling passages and cooling structure.

Smither, Robert K. (Hinsdale, IL)

1998-01-01T23:59:59.000Z

209

Aneta Siemiginowska Chandra X-ray Center  

E-Print Network (OSTI)

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

Wolfe, Patrick J.

210

Watershed in X-ray Astronomy  

Science Journals Connector (OSTI)

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

1971-01-08T23:59:59.000Z

211

X-Ray Identification of Element 104  

Science Journals Connector (OSTI)

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

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

1973-09-03T23:59:59.000Z

212

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

213

X-ray Practicals Series 1 Advanced Data Reduction  

E-Print Network (OSTI)

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

Meagher, Mary

214

X-ray absorption and resonant x-ray emission spectra by electric quadrupole excitation in light rare-earth systems  

Science Journals Connector (OSTI)

We have made precise theoretical calculations for both 2p3/2?4f x-ray absorption spectra and 3d?2p3/2 resonant x-ray emission spectra involving electric quadrupole excitations at the L3 edge of light rare-earth elements from La to Eu. It is shown that the energy separation of a double-peak structure observed by x-ray absorption spectroscopy (XAS) does not agree with that determined from resonant x-ray emission spectroscopy (RXES), in contrast to recent experimental results by Bartolomé et al. The reason for this difference is that the energy separation in XAS is determined by the 4f-4f interaction only, while that in RXES is determined by both 4f-4f and 3d-4f interactions.

M. Nakazawa; K. Fukui; H. Ogasawara; A. Kotani; C. F. Hague

2002-09-26T23:59:59.000Z

215

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.

216

Optimized Volumetric Scanning for X-Ray Array Sources  

SciTech Connect

Non-destructive evaluation (NDE) is the science and technology of determining non-invasively the internal structure of manufactured parts, objects, and materials. NDE application areas include medicine, industrial manufacturing, military, homeland security, and airport luggage screening. X-ray measurement systems are most widely used because of their ability to image through a wide range of material densities (from human tissue in medical applications to the dense materials of weapon components). Traditional x-ray systems involve a single source and detector system that rotate and/or translate about the object under evaluation. At each angular location, the source projects x-rays through the object. The rays undergo attenuation proportional to the density of the object's constitutive material. The detector records a measure of the attenuation. Mathematical algorithms are used to invert the forward attenuated ray projection process to form images of the object. This is known as computed tomography (CT). In recent years, the single-source x-ray NDE systems have been generalized to arrays of x-ray sources. Array sources permit multiple views of the object with fewer rotations and translations of the source/detector system. The spatially diverse nature of x-ray array sources has the potential of reducing data collection time, reducing imaging artifacts, and increasing the resolution of the resultant images. Most of the existing CT algorithms were not derived from array source models with a spatially diverse set of viewing perspectives. Single-source x-ray CT data collection, processing, and imaging methods and algorithms are not applicable when the source location is expanded from one dimension (a rotating and/or translating point source) to two (a rotating and/or translating array). They must be reformulated. The goal of this project is to determine the applicability of x-ray array sources to problems of interest to LLNL and its customers. It is believed array source data collection will be faster while yielding higher resolution reconstructions with fewer artifacts. There are three tasks in the research: (1) Develop forward array source analytic and computational models; (2) Research and develop array source reconstruction algorithms; and (3) Perform experiments.

Lehman, S K; Foudray, A M; Wang, A; Kallman, J S; Martz, H

2009-09-29T23:59:59.000Z

217

X-ray sources in globular clusters  

E-Print Network (OSTI)

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

Frank Verbunt

2001-11-22T23:59:59.000Z

218

Micellar structure from comparison of X-ray and neutron small-angle scattering  

E-Print Network (OSTI)

249 Micellar structure from comparison of X-ray and neutron small-angle scattering T. Zemb and P according to the method developed by Hayter and Penfold. Both X-ray and neutron scattering signals, or by a combination of both. It has been shown recent- ly [1, 2] that it is possible in neutron scattering studies

Boyer, Edmond

219

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

E-Print Network (OSTI)

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

Ã?stgaard, Nikolai

220

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

E-Print Network (OSTI)

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

Birmingham, University of

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

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

E-Print Network (OSTI)

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

Danon, Yaron

222

Modification of the TASMIP x-ray spectral model for the simulation of microfocus x-ray sources  

SciTech Connect

Purpose: The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammography. However, most of these models cannot be used directly for modeling microfocus x-ray sources due to differences in inherent filtration, energy range and/or anode material. For this reason the authors propose in this work a new model for the simulation of microfocus spectra based on existing models for mammography and radiology, modified to compensate for the effects of inherent filtration and energy range. Methods: The authors used the radiology and mammography versions of an existing empirical model [tungsten anode spectral model interpolating polynomials (TASMIP)] as the basis of the microfocus model. First, the authors estimated the inherent filtration included in the radiology model by comparing the shape of the spectra with spectra from the mammography model. Afterwards, the authors built a unified spectra dataset by combining both models and, finally, they estimated the parameters of the new version of TASMIP for microfocus sources by calibrating against experimental exposure data from a microfocus x-ray source. The model was validated by comparing estimated and experimental exposure and attenuation data for different attenuating materials and x-ray beam peak energy values, using two different x-ray tubes. Results: Inherent filtration for the radiology spectra from TASMIP was found to be equivalent to 1.68 mm Al, as compared to spectra obtained from the mammography model. To match the experimentally measured exposure data the combined dataset required to apply a negative filtration of about 0.21 mm Al and an anode roughness of 0.003 mm W. The validation of the model against real acquired data showed errors in exposure and attenuation in line with those reported for other models for radiology or mammography. Conclusions: A new version of the TASMIP model for the estimation of x-ray spectra in microfocus x-ray sources has been developed and validated experimentally. Similarly to other versions of TASMIP, the estimation of spectra is very simple, involving only the evaluation of polynomial expressions.

Sisniega, A.; Vaquero, J. J., E-mail: juanjose.vaquero@uc3m.es [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain); Instituto de Investigación Sanitaria Gregorio Marañón, Madrid ES28007 (Spain); Desco, M. [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain) [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid ES28911 (Spain); Instituto de Investigación Sanitaria Gregorio Marañón, Madrid ES28007 (Spain); Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid ES28029 (Spain)

2014-01-15T23:59:59.000Z

223

X-ray Absorption Spectroscopy of Biologically Relevant Systems  

E-Print Network (OSTI)

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

Uejio, Janel Sunayo

2010-01-01T23:59:59.000Z

224

Compact X-Ray Light Source Workshop | EMSL  

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

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

225

Biological Imaging by Soft X-Ray Diffraction Microscopy  

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

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

226

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

227

X-ray source for mammography  

DOE Patents (OSTI)

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

Logan, Clinton M. (Pleasanton, CA)

1994-01-01T23:59:59.000Z

228

Ultrafast X-Ray Sources and Science  

Science Journals Connector (OSTI)

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

Young, Linda

229

X-ray induced optical reflectivity  

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

Durbin, Stephen M.

2012-01-01T23:59:59.000Z

230

SMB, X-ray Emission Spectroscopy  

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

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

231

X-raying galaxies: A Chandra legacy  

Science Journals Connector (OSTI)

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

Q. Daniel Wang

2010-01-01T23:59:59.000Z

232

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

233

Femtosecond X-ray protein nanocrystallography  

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

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

234

X-ray source for mammography  

DOE Patents (OSTI)

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

Logan, C.M.

1994-12-20T23:59:59.000Z

235

Materials Small-angle X-ray Scattering (SAXS) | Stanford Synchrotron  

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

Materials Small-angle X-ray Scattering (SAXS) Materials Small-angle X-ray Scattering (SAXS) Small Angle X-ray Scattering for Materials Science Small-angle X-ray scattering (SAXS) is a well-established characterization method for microstructure investigations in various materials. It probes electron density differences to give information about structural inhomogeneities from the near atomic scale (1 nm) to the micron scale (1 000 nm). The method involves measuring the scattered X-ray intensity as a function of (typically small) scattering angles and is generally performed in transmission. SAXS is used to characterize the size scale of inhomogeneities (e.g. pores, inclusions, second phase regions) in polymer blends, micro-emulsions, geological materials, bones, cements and ceramics. Instrumentation

236

High power x-ray welding of metal-matrix composites  

DOE Patents (OSTI)

A method for joining metal-matrix composites (MMCs) by using high power x-rays as a volumetric heat source is provided. The method involves directing an x-ray to the weld line between two adjacent MMCs materials to create an irradiated region or melt zone. The x-rays have a power density greater than about 10.sup.4 watts/cm.sup.2 and provide the volumetric heat required to join the MMC materials. Importantly, the reinforcing material of the metal-matrix composites remains uniformly distributed in the melt zone, and the strength of the MMCs are not diminished. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys.

Rosenberg, Richard A. (Naperville, IL); Goeppner, George A. (Orland Park, IL); Noonan, John R. (Naperville, IL); Farrell, William J. (Flossmoor, IL); Ma, Qing (Westmont, IL)

1999-01-01T23:59:59.000Z

237

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

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

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

238

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.

239

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.

240

Lensless X-Ray Imaging in Reflection  

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

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

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


241

The Constellation X-ray mission  

Science Journals Connector (OSTI)

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

N.E White; H Tananbaum

1999-01-01T23:59:59.000Z

242

X-Ray Observations of Radio Galaxies  

E-Print Network (OSTI)

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

D. E. Harris

1998-04-20T23:59:59.000Z

243

Compton backscattered collimated x-ray source  

DOE Patents (OSTI)

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

Ruth, R.D.; Huang, Z.

1998-10-20T23:59:59.000Z

244

Compton backscattered collmated X-ray source  

DOE Patents (OSTI)

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

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

2000-01-01T23:59:59.000Z

245

Compton backscattered collimated x-ray source  

DOE Patents (OSTI)

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

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

1998-01-01T23:59:59.000Z

246

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.

247

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

E-Print Network (OSTI)

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

Sudip Bhattacharyya

2010-02-24T23:59:59.000Z

248

Region-of-interest reconstructions from truncated 3D x-ray projections  

E-Print Network (OSTI)

This paper introduces a method of region-of-interest (ROI) reconstruction from truncated 3D X-ray projections, consisting of a wavelet-based regularized iterative reconstruction procedure that, under appropriate conditions, converges within the ROI to an exact or highly accurate solution. ROI tomography is motivated by the goal to reduce the overall radiation exposure when primarily the reconstruction of a specified region rather than the entire object is required. Our approach assumes that only the 3D truncated X-ray projections, i.e., the projection data restricted to the image of the ROI, are known and does not assume any previous knowledge about the density function, except for standard assumptions about integrability and regularity needed to ensure that forward and backward transforms are well defined. We provide rigorous theoretical justification for the convergence of our regularized reconstruction algorithm in the continuous setting and prove the existence of a critical radius of a spherical ROI that ensures the convergence of the algorithm. Theoretical results are validated numerically using simulated acquisition and truncation of projection data for various acquisition geometries and ROI sizes and locations. We provide a numerical analysis of the ROI reconstruction stability as a function of the ROI size, showing that our algorithm converges also for ROI sizes which are rather small with respect to the support of the density function.

Robert Azencott; Bernhard G. Bodmann; Demetrio Labate; Anando Sen; Daniel Vera

2015-02-04T23:59:59.000Z

249

Standard test method for determination of bromine and chlorine in UF6 and uranyl nitrate by X-Ray fluorescence (XRF) spectroscopy  

E-Print Network (OSTI)

1.1 This method covers the determination of bromine (Br) and chlorine (Cl) in uranium hexafluoride (UF6) and uranyl nitrate solution. The method as written covers the determination of bromine in UF6 over the concentration range of 0.2 to 8 ?g/g, uranium basis. The chlorine in UF6 can be determined over the range of 4 to 160 ?g/g, uranium basis. Higher concentrations may be covered by appropriate dilutions. The detection limit for Br is 0.2 ?g/g uranium basis and for Cl is 4 ?g/g uranium basis. 1.2 This standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

American Society for Testing and Materials. Philadelphia

2001-01-01T23:59:59.000Z

250

An X-ray study of residual macrostresses in protective coatings for gas-turbine blades  

Science Journals Connector (OSTI)

The x-ray method is used to determine residual macrostresses in the surface layer of protective coatings on high-temperature alloys. Coatings deposited by the high-energy vacuum-plasma (HEVP) method were subje...

Yu. D. Yagodkin; K. M. Pastukhov; E. V. Milyaeva…

1997-11-01T23:59:59.000Z

251

X-ray Line Profile Analysis of Nanoparticles in Proton Exchange Membrane Fuel Cell Electrodes  

Science Journals Connector (OSTI)

We present a method to extract X-ray diffraction patterns from a multiphase system and analyze the particle size distribution of each phase. The method is demonstrated for crystalline nanoparticles in the electrodes of proton exchange membrane fuel cells (...

Matthias Loster; Davor Balzar; K. Andreas Friedrich; Jürgen Garche

2007-06-06T23:59:59.000Z

252

Analysis of Intrinsically Disordered Proteins by Small-Angle X-ray Scattering  

Science Journals Connector (OSTI)

Small-angle scattering of X-rays (SAXS) is a method for the low-resolution structural characterization of biological macromolecules in solution. The technique is highly complementary to the high-resolution method...

Pau Bernadó; Dmitri I. Svergun

2012-01-01T23:59:59.000Z

253

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.

254

X-ray photon correlation spectroscopy under flow  

E-Print Network (OSTI)

X-ray photon correlation spectroscopy was used to probe the diffusive dynamics of colloidal particles in a shear flow. Combining X-ray techniques with microfluidics is an experimental strategy that reduces the risk of x-ray induced beam damage and also allows time-resolved studies of processes taking place in flowcells. The experimental results and theoretical predictions presented here, show that in the low shear limit, for a ``transverse flow'' scattering geometry (scattering wave vector q perpendicular to the direction of flow) the measured relaxation times are independent of the flow rate and determined only by the diffusive motion of the particles. This is not generally valid and in particular, for a ``longitudinal flow'' (q || flow) scattering geometry, the relaxation times are strongly affected by the flow-induced motion of the particles. Our results show that the Brownian diffusion of colloidal particles can be measured in a flowing sample and that, up to flux limitations, the experimental conditions under which this is possible are easier to achieve at higher values of q.

Andrei Fluerasu; Abdellatif Moussaid; Henri Gleyzolle; Peter Falus; Anders Madsen

2008-03-10T23:59:59.000Z

255

X-ray Pinhole Camera Measurements  

SciTech Connect

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

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

2013-07-01T23:59:59.000Z

256

Nonlinear X-ray Compton Scattering  

E-Print Network (OSTI)

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

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

2015-01-01T23:59:59.000Z

257

Oscillations During Thermonuclear X-ray Bursts  

E-Print Network (OSTI)

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

Tod E. Strohmayer

2001-01-12T23:59:59.000Z

258

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.

259

Low Dose Radiation Research Program: A Variable Energy Soft X-ray  

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

Variable Energy Soft X-ray Microprobe to Investigate Mechanisms of Variable Energy Soft X-ray Microprobe to Investigate Mechanisms of the Radiation Induced Bystander Effect. Authors: Melvyn Folkard, Borivoj Vojnovic, Giuseppe Schettino, Kevin M Prise and Barry D Michael. Institutions: Gray Cancer Institute. We are currently engaged on two projects in the Low-dose Program: "Low dose studies with focused X-rays in cell and tissue models: mechanisms of bystander and genomic instability responses" (DE-FG07-99ER62877) and "Mechanistic modeling of bystander effects: An integrated theoretical and experimental approach" (DE-FG02-02ER63305). Central to both of these studies is a unique micro irradiation facility that uses ultrasoft X-rays focused to a sub micron beam for individual cell and sub cellular targeting. This facility allows us to selectively irradiate individual

260

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

E-Print Network (OSTI)

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

Bautz, Marshall W.

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

Differential phase contrast X-ray imaging system and components  

DOE Patents (OSTI)

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

Stutman, Daniel; Finkenthal, Michael

2014-07-01T23:59:59.000Z

262

Kaonic hydrogen X-ray measurement in SIDDHARTA  

E-Print Network (OSTI)

Kaonic hydrogen atoms provide a unique laboratory to probe the kaon-nucleon strong interaction at the energy threshold, allowing an investigation of the interplay between spontaneous and explicit chiral symmetry breaking in low-energy QCD. The SIDDHARTA Collaboration has measured the $K$-series X rays of kaonic hydrogen atoms at the DA$\\Phi$NE electron-positron collider of Laboratori Nazionali di Frascati, and has determined the most precise values of the strong-interaction induced shift and width of the $1s$ atomic energy level. This result provides vital constraints on the theoretical description of the low-energy $\\bar{K}N$ interaction.

M. Bazzi; G. Beer; L. Bombelli; A. M. Bragadireanu; M. Cargnelli; G. Corradi; C. Curceanu; A. d'Uffizi; C. Fiorini; T. Frizzi; F. Ghio; C. Guaraldo; R. S. Hayano; M. Iliescu; T. Ishiwatari; M. Iwasaki; P. Kienle; P. Levi Sandri; A. Longoni; V. Lucherini; J. Marton; S. Okada; D. Pietreanu; T. Ponta; A. Rizzo; A. Romero Vidal; A. Scordo; H. Shi; D. L. Sirghi; F. Sirghi; H. Tatsuno; A. Tudorache; V. Tudorache; O. Vazquez Doce; E. Widmann; J. Zmeskal

2012-01-23T23:59:59.000Z

263

Borman effect in resonant diffraction of X-rays  

SciTech Connect

A dynamic theory of resonant diffraction (occurring when the energy of incident radiation is close to the energy of the absorption edge of an element in the composition of a given substance) of synchronous X-rays is developed in the two-wave approximation in the coplanar Laue geometry for large grazing angles in perfect crystals. A sharp decrease in the absorption coefficient in the substance with simultaneously satisfied diffraction conditions (Borman effect) is demonstrated, and the theoretical and first experimental results are compared. The calculations reveal the possibility of applying this approach in analyzing the quadrupole-quadrupole contribution to the absorption coefficient.

Oreshko, A. P., E-mail: ap.oreshko@physics.msu.ru [Moscow State University (Russian Federation)

2013-08-15T23:59:59.000Z

264

X-ray variability in M87  

E-Print Network (OSTI)

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

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

1996-12-05T23:59:59.000Z

265

Displaced Vertices from X-ray Lines  

E-Print Network (OSTI)

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

Adam Falkowski; Yonit Hochberg; Joshua T. Ruderman

2014-09-09T23:59:59.000Z

266

Stratigraphic correlation with X-ray powder patterns  

E-Print Network (OSTI)

of certain metallic trace elements, notably magnesium, iron, aluminum, and strontium, and on this basis were able to pick out sones within a thick limestone section which could not be difi'erentiated by ord1nary methods. As an alternative or ad...STRATIGRAPHIC CORRELATION MITH X-RAY PONDER PATTERNS John B. Singletary A Thesis Submitted to the Graduate School Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE MA...

Singletary, John B

2012-06-07T23:59:59.000Z

267

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

268

Time-resolved x-ray diagnostics  

SciTech Connect

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

Lyons, P.B.

1981-01-01T23:59:59.000Z

269

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

E-Print Network (OSTI)

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

Piana, Michele

270

Water Window Ptychographic Imaging with Characterized Coherent X-rays  

E-Print Network (OSTI)

We report on a ptychographical coherent diffractive imaging experiment in the water window with focused soft X-rays at $500~\\mathrm{eV}$. An X-ray beam with high degree of coherence was selected for ptychography at the P04 beamline of the PETRA III synchrotron radiation source. We measured the beam coherence with the newly developed non-redundant array method. A pinhole $2.6~\\mathrm{\\mu m}$ in size selected the coherent part of the beam and was used for ptychographic measurements of a lithographically manufactured test sample and fossil diatom. The achieved resolution was $53~\\mathrm{nm}$ for the test sample and only limited by the size of the detector. The diatom was imaged at a resolution better than $90~\\mathrm{nm}$.

Rose, Max; Dzhigaev, Dmitry; Gorobtsov, Oleg; Senkbeil, Tobias; von Gundlach, Andreas; Gorniak, Thomas; Shabalin, Anatoly; Viefhaus, Jens; Rosenhahn, Axel; Vartanyants, Ivan

2015-01-01T23:59:59.000Z

271

Imaging Antifungal Drug Molecules in Action using Soft X-Ray...  

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

a cell. This use of soft x-ray tomography is now generating considerable interest in the pharmaceutical industry as a potential method for reducing the cost and time it takes to...

272

Thin optic surface analysis for high resolution X-ray telescopes  

E-Print Network (OSTI)

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

Akilian, Mireille

2004-01-01T23:59:59.000Z

273

X-Ray Astronomy to Resonant Theranostics for Cancer Treatment Sultana N. Nahar  

E-Print Network (OSTI)

1 X-Ray Astronomy to Resonant Theranostics for Cancer Treatment Sultana N. Nahar Abstract Atomic this connection, we have formulated a new method, Resonant Nano-Plasma Theranostics or RNPT, which gives

Nahar, Sultana Nurun

274

Characterization of nuclear physics targets using Rutherford backscattering and particle induced x-ray emission  

E-Print Network (OSTI)

Rutherford backscattering and particle induced x-ray emission have been utilized to precisely characterize targets used in nuclear fission experiments. The method allows for a fast and non destructive determination of target thickness, homogeneity and element composition.

Th. Rubehn; G. J. Wozniak; L. Phair; L. G. Moretto; Kin M. Yu

1996-09-23T23:59:59.000Z

275

Thermal and Bulk Comptonization in Accretion-powered X-Ray Pulsars  

Science Journals Connector (OSTI)

We develop a new theoretical model for the spectral formation process in accretion-powered X-ray pulsars based on a detailed treatment of the bulk and thermal Comptonization occurring in the accreting, shocked gas. A rigorous eigenfunction expansion method is employed to obtain the analytical solution for the Green's function describing the scattering of radiation injected into the column from a monochromatic source located at an arbitrary height above the stellar surface. The emergent spectrum is calculated by convolving the Green's function with source terms corresponding to bremsstrahlung, cyclotron, and blackbody emission. The energization of the photons in the shock, combined with cyclotron absorption, naturally produces an X-ray spectrum with a relatively flat continuum shape and a high-energy quasi-exponential cutoff. We demonstrate that the new theory successfully reproduces the phase-averaged spectra of the bright pulsars Her X-1, LMC X-4, and Cen X-3. In these luminous sources, it is shown that the emergent spectra are dominated by Comptonized bremsstrahlung emission.

Peter A. Becker; Michael T. Wolff

2007-01-01T23:59:59.000Z

276

Ultraviolet observations of the X-ray photoionized wind of Cygnus X-1 during X-ray soft/high state  

E-Print Network (OSTI)

(Shortened) Ultraviolet observations of the black hole X-ray binary Cygnus X-1 were obtained using the STIS on HSTubble. We detect P Cygni line features show strong, broad absorption components when the X-ray source is behind the companion star and noticeably weaker absorption when the X-ray source is between us and the companion star. We fit the P Cygni profiles using the SEI method applied to a spherically symmetric stellar wind subject to X-ray photoionization from the black hole. The Si IV doublet provides the most reliable estimates of the parameters of the wind and X-ray illumination. The velocity $v$ increases with radius $r$ according to $v=v_\\infty(1-r_\\star/r)^\\beta$, with$\\beta\\approx0.75$ and $v_\\infty\\approx1420$ km s$^{-1}$.The microturbulent velocity was $\\approx160$ km s$^{-1}$. Our fit implies a ratio of X-ray luminosity to wind mass-loss rate of L$_{X,38}/\\dot M_{-6} \\approx 0.33$, measured at $\\dot M_{-6}$ = 4.8. Our models determine parameters that may be used to estimate the accretion rat...

Vrtilek, S D; Hunacek, A; Gies, D; Bolton, C T

2007-01-01T23:59:59.000Z

277

Quantitative determination of mineral composition by powder x-ray diffraction  

DOE Patents (OSTI)

An external standard intensity ratio method is used for quantitatively determining mineralogic compositions of samples by x-ray diffraction. The method uses ratios of x-ray intensity peaks from a single run. Constants are previously determined for each mineral which is to be quantitatively measured. Ratios of the highest intensity peak of each mineral to be quantified in the sample and the highest intensity peak of a reference mineral contained in the sample are used to calculate sample composition.

Pawloski, G.A.

1984-08-10T23:59:59.000Z

278

The New X-Ray Lithography Beamline BL1 At DELTA  

SciTech Connect

Lithography using synchrotron radiation in the x-ray regime provides a powerful method to produce mechanical components of sub-millimeter size with a very good quality for microtechnological applications. In recent years the demand for x-ray lithography beamtime for industrial production of microparts increased rapidly resulting in the development of new experimental endstations at synchrotron radiation sources dedicated for the production of micromechanical devices. We present in this work the layout of the new x-ray lithography beamline BL1 at the synchrotron radiation source DELTA in Dortmund and discuss first results of exposure tests.

Lietz, D.; Paulus, M.; Sternemann, C.; Berges, U.; Hippert, B.; Tolan, M. [Fakultaet Physik / DELTA, TU Dortmund, Maria-Goeppert-Mayer-Str. 2, 44227 Dortmund (Germany)

2010-06-23T23:59:59.000Z

279

X-Ray Entangled Photon Production in Collisions of Laser Beams with Relativistic Ions  

E-Print Network (OSTI)

A method is suggested to produce, with the help of colliding laser photons with bunches of relativistic ions having two energy levels, both intense beams of monochromatic polarized X-ray fluorescence photons and significant number of X-ray entangled photons, via double Doppler transformation. Nonlinear susceptibility of the ions, the cross section and the rate of production of such photons at RHIC are estimated. Such beams of X-ray photons can be detected and applied to solve various problems, in a manner similar to the usage of optical photons.

K. A. Ispirian; M. K. Ispiryan

2010-04-02T23:59:59.000Z

280

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.

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

Radioactive Thulium for X-Rays  

Science Journals Connector (OSTI)

Radioactive power from thulium makes Argonne x-ray unit a potential for medical and industrial use ... Active component of the instrument is a tiny particle (one-fifth gram) of thulium-170 which has been made radioactive in a heavy water nuclear reactor at Arco, Idaho. ...

1954-05-03T23:59:59.000Z

282

X-ray spectroscopy of manganese clusters  

SciTech Connect

Much of this thesis represents the groundwork necessary in order to probe Mn clusters more productively than with conventional Mn K-edge XAS and is presented in Part 1. Part 2 contains the application of x-ray techniques to Mn metalloproteins and includes a prognosis at the end of each chapter. Individual Mn oxidation states are more readily distinguishable in Mn L-edge spectra. An empirical mixed valence simulation routine for determining the average Mn oxidation state has been developed. The first Mn L-edge spectra of a metalloprotein were measured and interpreted. The energy of Mn K{beta} emission is strongly correlated with average Mn oxidation state. K{beta} results support oxidation states of Mn(III){sub 2}(IV){sub 2} for the S{sub 1} state of Photosystem II chemical chemically reduced preparations contain predominantly Mn(II). A strength and limitation of XAS is that it probes all of the species of a particular element in a sample. It would often be advantageous to selectively probe different forms of the same element. The first demonstration that chemical shifts in x-ray fluorescence energies can be used to obtain oxidation state-selective x-ray absorption spectra is presented. Spin-dependent spectra can also be used to obtain a more simplified picture of local structure. The first spin-polarized extended x-ray absorption fine structure using Mn K{beta} fluorescence detection is shown.

Grush, M.M. [Univ. of California, Davis, CA (United States). Dept. of Applied Science; [Lawrence Berkeley National Lab., CA (United States). Energy and Environment Div.

1996-06-01T23:59:59.000Z

283

Soft x-ray laser microscope  

SciTech Connect

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

284

Small Angle X-Ray Scattering Detector  

DOE Patents (OSTI)

A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., q.sub.max /q.sub.min.congruent.100.

Hessler, Jan P. (Downers Grove, IL)

2004-06-15T23:59:59.000Z

285

SLAC All Access: X-ray Microscope  

ScienceCinema (OSTI)

SLAC physicists Johanna Nelson and Yijin Liu give a brief overview of the X-ray microscope at the Stanford Synchrotron Radiation Lightsource (SSRL) that is helping improve rechargeable-battery technology by letting researchers peek into the inner workings of batteries as they operate.

Nelson, Johanna; Liu, Yijin

2014-06-13T23:59:59.000Z

286

A Population of Ultraluminous X-ray Sources with An Accreting Neutron Star  

E-Print Network (OSTI)

Most ultraluminous X-ray sources (ULXs) are believed to be X-ray binary systems, but previous observational and theoretical studies tend to prefer a black hole rather than a neutron star accretor. The recent discovery of 1.37 s pulsations from the ULX M82 X-2 has established its nature as a magnetized neutron star. In this work we model the formation history of neutron star ULXs in an M82- or Milky Way-like galaxy, by use of both binary population synthesis and detailed binary evolution calculations. We find that the birthrate is around $10^{-4}\\, \\rm yr^{-1}$ for the incipient X-ray binaries in both cases. We demonstrate the distribution of the ULX population in the donor mass - orbital period plane. Our results suggest that, compared with black hole X-ray binaries, neutron star X-ray binaries may significantly contribute to the ULX population, and high-mass and intermediate-mass X-ray binaries dominate the neutron star ULX population in M82- and Milky Way-like galaxies, respectively.

Shao, Yong

2015-01-01T23:59:59.000Z

287

A Compact Pressure-Insulated Electrostatic X-Ray Generator  

Science Journals Connector (OSTI)

A compact, pressure-insulated, electrostatic x-ray generator has been developed for scientific and medical purposes. A major object of the work was the investigation, with a small and thus flexible machine, of the principles and design factors involved in pressure-insulated electrostatic generators with a view to the subsequent development of higher voltages in compact apparatus. The generator is housed in a steel tank 34 in. in diameter and 100 in. high. At air pressures of 11 atmospheres absolute, 1250-kv x-rays are obtained with target currents of over one milliampere supplied by the single 14-in. belt. With Freon gas the same voltages and currents can be obtained at one-third the pressure required with air. The problem of belt charge is analyzed and a method is described for controlling the electrostatic fields within the column in order to realize the high charge densities possible at high pressure. The construction of a supporting column of high breakdown strength, and other features of the design are described. At 1250 kv the x-ray intensity per milliampere of target current is about 340 roentgens per minute at 50 cm from the target in the direction of the electron beam with five mm of lead equivalent filtration.

John G. Trump and R. J. van de Graaff

1939-06-15T23:59:59.000Z

288

Synchrotron x-ray fluorescence and extended x-ray absorption fine structure analysis  

SciTech Connect

The advent of dedicated synchrotron radiation sources has led to a significant increase in activity in many areas of science dealing with the interaction of x-rays with matter. Synchrotron radiation provides intense, linearly polarized, naturally collimated, continuously tunable photon beams, which are used to determine not only the elemental composition of a complex, polyatomic, dilute material but also the chemical form of the elements with improved accuracy. Examples of the application of synchrotron radiation include experiments in synchrotron x-ray fluorescence (SXRF) analysis and extended x-ray absorption fine structure (EXAFS) analysis. New synchrotron radiation x-ray microprobes for elemental analysis in the parts per billion range are under construction at several laboratories. 76 references, 24 figures.

Chen, J.R.; Gordon, B.M.; Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Chao, E.C.T.; Minkin, J.A.

1984-01-01T23:59:59.000Z

289

X-ray imaging crystal spectrometer for extended X-ray sources  

DOE Patents (OSTI)

Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokomak fusion experiment to provide spatially and temporally resolved data on plasma parameters using the imaging properties for Bragg angles near 45. For a Bragg angle of 45.degree., the spherical crystal focuses a bundle of near parallel X-rays (the cross section of which is determined by the cross section of the crystal) from the plasma to a point on a detector, with parallel rays inclined to the main plain of diffraction focused to different points on the detector. Thus, it is possible to radially image the plasma X-ray emission in different wavelengths simultaneously with a single crystal.

Bitter, Manfred L. (Princeton, NJ); Fraenkel, Ben (Jerusalem, IL); Gorman, James L. (Bordentown, NJ); Hill, Kenneth W. (Lawrenceville, NJ); Roquemore, A. Lane (Cranbury, NJ); Stodiek, Wolfgang (Princeton, NJ); von Goeler, Schweickhard E. (Princeton, NJ)

2001-01-01T23:59:59.000Z

290

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

291

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

292

X-ray microscopy using grazing-incidence reflection optics  

SciTech Connect

The Kirkpatrick-Baez microscopes are described along with their role as the workhorse of the x-ray imaging devices. This role is being extended with the development of a 22X magnification Kirkpatrick-Baez x-ray microscope with multilayer x-ray mirrors. These mirrors can operate at large angles, high x-ray energies, and have a narrow, well defined x-ray energy bandpass. This will make them useful for numerous experiments. However, where a large solid angle is needed, the Woelter microscope will still be necessary and the technology needed to build them will be useful for many other types of x-ray optics.

Price, R.H.

1981-08-06T23:59:59.000Z

293

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

SciTech Connect

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

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

2013-03-20T23:59:59.000Z

294

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

SciTech Connect

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

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

2013-05-15T23:59:59.000Z

295

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-

296

Element 104 identified by characteristic x rays  

Science Journals Connector (OSTI)

A research team at the Oak Ridge National Laboratory has recently announced that they have conclusively identified the 257 isotope of element 104. This new work shows promise of shedding light on the controversy between Albert Ghiorso and Georgi N. Flerov the leaders respectively of the groups at Lawrence Berkeley Laboratory and the Joint Institute for Nuclear Research Dubna. The isotope 104 X 257 decays by alpha emission to 102 No 253 with a half?life of 4.3 seconds. The Oak Ridge group observed the K?series x rays from nobelium in coincidence with the alpha particles from 104 X 257 ; the observation of x?ray spectra has never been reported previously by the Berkeley or Dubna workers according to Curtis E. Bemis Jr spokesman for the group.

Ronald J. Cohn

1973-01-01T23:59:59.000Z

297

Sample holder for X-ray diffractometry  

DOE Patents (OSTI)

A sample holder for use with X-ray diffractometers with the capability to rotate the sample, as well as to adjust the position of the sample in the x, y, and z directions. Adjustment in the x direction is accomplished through loosening set screws, moving a platform, and retightening the set screws. Motion translators are used for adjustment in the y and z directions. An electric motor rotates the sample, and receives power from the diffractometer.

Hesch, Victor L. (Los Alamos, NM)

1992-01-01T23:59:59.000Z

298

Columbia University X-Ray Measurements  

E-Print Network (OSTI)

V-720 keV · NaI 2x2x2" detector views an energy range of 1 keV-3 MeV Store signal in the tree. computer configuration. Plasmas were created using multi-frequency ECRH, and we find that most of the plasma energy is stored in the fast electrons. The energy spectrum of the x-ray emission below 740 keV is measured

299

Silicon Absolute X-Ray Detectors  

SciTech Connect

The responsivity of silicon photodiodes having no loss in the entrance window, measured using synchrotron radiation in the 1.75 to 60 keV range, was compared to the responsivity calculated using the silicon thickness measured using near-infrared light. The measured and calculated responsivities agree with an average difference of 1.3%. This enables their use as absolute x-ray detectors.

Seely, John F. [Naval Research Laboratory, Washington, D.C. 20375 (United States); Korde, Raj; Sprunck, Jacob [International Radiation Detectors, Inc., Torrance, CA 90505-5243 (United States); Medjoubi, Kadda; Hustache, Stephanie [Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette CEDEX (France)

2010-06-23T23:59:59.000Z

300

Ultrashort x-ray backlighters and applications  

SciTech Connect

Previously, using ultrashort laser pulses focused onto solid targets, we have experimentally studied a controllable ultrafast broadband radiation source in the extreme ultraviolet for time-resolved dynamical studies in ultrafast science [J. Workman, A. Maksimchuk, X. Llu, U. Ellenberger, J. S. Coe, C.-Y. Chien, and D. Umstadter, ``Control of Bright Picosecond X-Ray Emission from Intense Sub- Picosecond Laser-Plasma Interactions,`` Phys. Rev. Lett. 75, 2324 (1995)]. Once armed with a bright ultrafast broadband continuum x-ray source and appropriate detectors, we used the source as a backlighter to study a remotely produced plasma. The application of the source to a problem relevant to high-density matter completes the triad: creating and controlling, efficiently detecting, and applying the source. This work represented the first use of an ultrafast laser- produced x-ray source as a time-resolving probe in an application relevant to atomic, plasma and high-energy-density matter physics. Using the x-ray source as a backlighter, we adopted a pump-probe geometry to investigate the dynamic changes in electronic structure of a thin metallic film as it is perturbed by an ultrashort laser pulse. Because the laser deposits its energy in a skin depth of about 100 {Angstrom} before expansion occurs, up to gigabar pressure shock waves lasting picosecond in duration have been predicted to form in these novel plasmas. This raises the possibility of studying high- energy-density matter relevant to inertial confinement fusion (ICF) and astrophysics in small-scale laboratory experiments. In the past, time-resolved measurements of K-edge shifts in plasmas driven by nanosecond pulses have been used to infer conditions in highly compressed materials. In this study, we used 100-fs laser pulses to impulsively drive shocks into a sample (an untamped 1000 {Angstrom} aluminum film on 2000 {Angstrom} of parylene-n), measuring L-edge shifts.

Umstadter, D., University of Michigan

1997-08-01T23:59:59.000Z

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301

X-ray holography at Lawrence Livermore National Laboratory  

SciTech Connect

The x-ray holography program at the Lawrence Livermore National Laboratory has two principal goals: (1) the development of x-ray diffraction techniques for DNA sequence analysis and (2) the development of x-ray laser holography for structural analysis of intact biological cells and organelles. DNA sequence analysis will be accomplished by applying x-ray diffraction techniques to determine the ensemble average of the sequence of labels along the individual elements of crystalline DNA. X-ray laser holographic imaging will be accomplished by applying three dimensional x-ray holography to elucidate the structure of few hundred angstrom objects such as 300 {Angstrom} chromatin fibers, nuclear pores and nucleic acid replication complexes in living cells. Existing laboratory x-ray lasers will be utilized to produce flash x-ray holograms of the biological structures.

Trebes, J.; Annese, C.; Birdsall, D.; Brase, J.; Gray, J.; Lane, S.; London, R.; Matthews, D.; Peters, D.; Pinkel, D.; Stone, G.; Rapp, D.; Rosen, M.; Weier, U.; Yorkey, T.

1990-10-11T23:59:59.000Z

302

X-Ray Diffraction Microscopy of Magnetic Structures  

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

X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing...

303

X-ray diffraction study of zirconia pillared clays  

Science Journals Connector (OSTI)

X-ray powder diffraction (XRPD) and X-ray radial electronic distribution density (RED) of initial and zirconia-pillared interlayered clays (Zr-PILC) were studied. After pillaring, the basal ... under air to 17.7 ...

D.A. Zyuzin; E.M. Moroz; T.G. Kuznetsova…

2004-01-01T23:59:59.000Z

304

Development of a Schwarzschild-type x-ray microscope  

Science Journals Connector (OSTI)

A Schwarzschild-type x-ray microscope has been designed, constructed, and tested. Ni/C multilayers were used as the x-ray mirrors, with a thickness (2d) of 7 nm and 30 layer pairs. The...

Kado, M; Yamashita, K; Ohtani, M; Tanaka, K A; Kodama, R; Kitamoto, S; Yamanaka, T; Nakai, S

1991-01-01T23:59:59.000Z

305

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...

306

A Record Run for the APS X-ray Source  

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

2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed A Record Run for the APS X-ray Source FEBRUARY 23, 2012 Bookmark and Share The APS storage ring. X-ray beams and...

307

Resonant Soft X-Ray Scattering - Combining Structural with Spectroscop...  

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

Resonant Soft X-Ray Scattering - Combining Structural with Spectroscopic Refinement Friday, September 28, 2012 - 10:00am SLAC, Bldg. 137, Room 322 SSRL Presents Kevin Stone X-ray...

308

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.

309

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

310

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.

311

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.

312

Full-field Transmission X-ray Microscopy | Stanford Synchrotron Radiation  

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

BL6-2c / Transmission X-ray Microscopy BL6-2c / Transmission X-ray Microscopy Home Researchers Publications Science Highlights Department of Energy Office of Science Search form Search Search TXM Search Full-field Transmission X-ray Microscopy Capabilities Full-field TXM is an excellent method to examine nanoscale heterogeneties in many materials, including complex hierarchical systems such as catalysts, fuel cells and battery electrodes, and biological and environmental samples, at 30 nm resolution.The transmission X-ray microscope (TXM) on beam line 6-2c at SSRL is capable of 2D imaging and tomography, as well as spectroscopic imaging for 2D and 3D elemental mapping and chemical mapping over tens of microns (up to mm in 2D). The field of view (FOV) is 30 microns, but mosaic images can be collected to

313

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

E-Print Network (OSTI)

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

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

2011-01-01T23:59:59.000Z

314

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

315

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

316

The X-ray Telescope of CAST  

E-Print Network (OSTI)

The Cern Axion Solar Telescope (CAST) is in operation and taking data since 2003. The main objective of the CAST experiment is to search for a hypothetical pseudoscalar boson, the axion, which might be produced in the core of the sun. The basic physics process CAST is based on is the time inverted Primakoff effect, by which an axion can be converted into a detectable photon in an external electromagnetic field. The resulting X-ray photons are expected to be thermally distributed between 1 and 7 keV. The most sensitive detector system of CAST is a pn-CCD detector combined with a Wolter I type X-ray mirror system. With the X-ray telescope of CAST a background reduction of more than 2 orders off magnitude is achieved, such that for the first time the axion photon coupling constant g_agg can be probed beyond the best astrophysical constraints g_agg < 1 x 10^-10 GeV^-1.

M. Kuster; H. Bräuninger; S. Cébrian; M. Davenport; C. Elefteriadis; J. Englhauser; H. Fischer; J. Franz; P. Friedrich; R. Hartmann; F. H. Heinsius; D. H. H. Hoffmann; G. Hoffmeister; J. N. Joux; D. Kang; K. Königsmann; R. Kotthaus; T. Papaevangelou; C. Lasseur; A. Lippitsch; G. Lutz; J. Morales; A. Rodríguez; L. Strüder; J. Vogel; K. Zioutas

2007-05-10T23:59:59.000Z

317

Applications of holography to x-ray imaging  

SciTech Connect

In this paper we consider various applications of holographic techniques to the problem of soft x-ray imaging. We give special attention to imaging biological material using x-rays in the wavelength range 24 to 45A. We describe some experiments on formation and reconstruction of x-ray holograms and propose some ways in which holographic techniques might contribute to the difficult problem of fabricating optical elements for use in the soft x-ray region.

Howells, M.; Iarocci, M.; Kenney, J.; Rarback, H.; Rosser, R.; Yun, W.

1985-03-01T23:59:59.000Z

318

Applications of holography to X-ray imaging  

SciTech Connect

In this paper the authors consider various applications of holographic techniques to the problem of soft x-ray imaging. Special attention is given to imaging biological material using x-rays in the wavelength range 24-45A. The authors describe some experiments on formation and reconstruction of x-ray holograms and propose some ways in which holographic techniques might contribute to the difficult problem of fabricating optical elements for use in the soft x-ray region.

Howells, M.; Iarocci, M.; Kenney, J.; Rarback, H.; Rosser, R.; Yun, W.

1985-01-01T23:59:59.000Z

319

X-ray MicroCT Training Presentation  

E-Print Network (OSTI)

X-ray MicroCT Training Presentation T. Fettah Kosar, PhD Center for Nanoscale Systems Harvard) Model: HMXST225 (max. 225 kV) #12;Overview 3 Introduction to X-ray imaging and Computed Tomography (CT) · What are X-rays and how do we generate and image them? · How do we magnify X-ray images and keep them

320

Optimizing and characterizing grating efficiency for a soft X-ray emission spectrometer  

Science Journals Connector (OSTI)

The efficiency of soft X-ray diffraction gratings is examined using theoretical calculations with new open-source software, and insights to design a high-performance emission spectrometer are applied. The calculated and measured efficiencies of real-world gratings are compared, and discrepancies are explained by incorporating real-world effects into the calculations.

Boots, M.

2013-02-06T23:59:59.000Z

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

Quantitative x-ray imager (abstract)  

SciTech Connect

We report on development of a quantitative x-ray imager (QXI) for the national Inertial Confinement Fusion Program. Included in this development is a study of photocathode response as a function of photon energy, 2--17.5 keV, which is related to diagnostic development on the National Ignition Facility (NIF). The QXI is defined as being a quantative imager due to the repeated characterization. This instrument is systematically checked out, electronically as well as its photocathode x-ray response, both on a direct current and pulsed x-ray sources, before and after its use on a shot campaign. The QXI is a gated x-ray imager1 used for a variety of experiments conducted in the Inertial Confinement Fusion and Radiation Physics Program. The camera was assembled in Los Alamos and has been under development since 1997 and has now become the workhorse framing camera by the program. The electronics were built by Grant Applied Physics of San Fransisco, CA.2 The QXI has been used at the LANL Trident, LLNL Nova, and University of Rochester Laboratory OMEGA laser facilities. The camera consists of a grated microchannel plate (MCP), a phosphor coated fiberoptic faceplate coupled to film for data readout, along with high speed electronic pulsers to drive the x-ray detector. The QXI has both a two-strip and a four-strip detection head and has the ability to individually bias the gain of each of the strips. The timing of the QXI was done at the Trident short pulse laboratory, using 211 nm light. Single strip jitter was looked at as well and determined to be <25 ps. Flatfielding of the photocathode across the MCP was done with the Trident main laser with 150 J on a gold disk with a 1 ns. Spatial resolution was determined to be <5 {mu}m by using the same laser conditions as before and a backlit 1000 lp/in. grid. The QXI has been used on cylindrical implosion work at the Nova Laser Facility, and on direct-drive cylinder mix and indirect-drive high convergence implosion experiments at OMEGA. Its two-strip module has provided the capability to look at point backlighters, as part of technique development for experiments on the NIF. Its next use will be in March 2000 with its off axis viewer nose at Omega, providing a perpendicular view of Rayleigh--Taylor spike dissipation.

Evans, Scott C.; Archuleta, Tom N.; Oertel, John A.; Walsh, Peter J.

2001-01-01T23:59:59.000Z

322

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.

323

Improvement of YOHKOH Hard X-Ray Imaging  

Science Journals Connector (OSTI)

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

Jun Sato; Takeo Kosugi; Kazuo Makishima

1999-02-01T23:59:59.000Z

324

Small Angle X-ray Scattering (SAXS) Laboratory Learning Experiences  

E-Print Network (OSTI)

.A. & Svergun D.I. (1987). Structure Analysis by Small-Angle X-Ray and Neutron Scattering. NY: Plenum PressSmall Angle X-ray Scattering (SAXS) Laboratory Learning Experiences o - Use of small angle X-ray scattering instrumentation o - Programs that you will use SAXS (BRUKER AXS) PRIMUS (Konarev, Volkov, Koch

Meagher, Mary

325

X-ray Diffraction Laboratory Department of Chemistry  

E-Print Network (OSTI)

X-ray Diffraction Laboratory Department of Chemistry Texas A & M University College Station, Texas Phone : 979-845-9125 www.chem.tamu.edu/xray xray@tamu.edu X-rayDiffractionLaboratory DepartmentofChemistry 3255TAMU CollegeStation,TX77843-3255 Mission The purpose of our laboratory is to provide X-ray

Meagher, Mary

326

X-ray Diffraction Practicals 1 Graphics Programs  

E-Print Network (OSTI)

X-ray Diffraction Practicals 1 Graphics Programs that will read SHELX or CIF files J. Reibenspies, N. Bhuvanesh ver 1.0.0 #12;X-ray Diffraction Practicals 2 Free software. Gretep : Reads SHELX files shelx files or output thermal ellipsoid plots. http://www.umass.edu/microbio/rasmol/ #12;X-ray

Meagher, Mary

327

X-ray Emission from Massive Stars David Cohen  

E-Print Network (OSTI)

X-ray Emission from Massive Stars David Cohen Department of Physics and Astronomy Swarthmore University, Oct. 13, 2005 astro.swarthmore.edu/~cohen/ #12;Outline 1. What you need to know: a. X-rays from the Sun - magnetic activity, x-ray spectra b. Hot stars c. Radiation-driven winds and the Doppler shift d

Cohen, David

328

X-Ray Photoelectron Spectroscopy XPS Mark Engelhard  

E-Print Network (OSTI)

X-Ray Photoelectron Spectroscopy XPS Mark Engelhard 1 #12;EMSL XPS Instrumentation 2 Physical Electronics Quantera XPS High Energy Resolution Focused X-ray Beam Capability Catalysis reaction and processing chamber with inert atmosphere glove box connected to a PHI Quantera Scanning X-ray Microprobe

329

Exact limiting relation between the structure factors in neutron and x-ray scattering  

E-Print Network (OSTI)

The ratio of the static matter structure factor measured in experiments on coherent X-ray scattering to the static structure factor measured in experiments on neutron scattering is considered. It is shown theoretically that this ratio in the long-wavelength limit is equal to the nucleus charge at arbitrary thermodynamic parameters of a pure substance (the system of nuclei and electrons, where interaction between particles is pure Coulomb) in a disordered equilibrium state. This result is the exact relation of the quantum statistical mechanics. The experimental verification of this relation can be done in the long wavelength X-ray and neutron experiments.

V. B. Bobrov; S. A. Trigger; S. N. Skovorod'ko

2010-07-11T23:59:59.000Z

330

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

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

331

Theoretical X-ray line profiles from colliding wind binaries  

Science Journals Connector (OSTI)

......106 Mo yr1 the lower energy lines (E 1 keV) are...Chandra Low- and High-Energy Transmission Grating...Skinner et al. 2001) and Car (Corcoran et al. 2001...it actually is. The alternative is to assume that all...noticeable for the lower energy lines (E 1 keV). These......

David B. Henley; Ian R. Stevens; Julian M. Pittard

2003-12-11T23:59:59.000Z

332

Geometry and X-ray diffraction characteristics of carbon nanotubes  

SciTech Connect

Algorithms for generating atomic coordinates in nanotubes with an arbitrary cell in the layer plane have been developed. The conditions for the seamless matching of a flat layer rolled up in any direction are formulated for cylindrical, conical, and faceted tubes. A method has been developed for generating different types of faceted nanotubes using a group transformation (obtained in this study) that leaves invariant an arbitrary polygon in the nanotube cross section. Equations are proposed for deriving the diameter and chirality of single-wall carbon cylindrical nanotubes from X-ray diffraction spectra.

Pleshakov, V. F., E-mail: victorpleshakov@list.ru [FGUP Scientific Research Institute of Electrical Carbon Products (Russian Federation)

2009-12-15T23:59:59.000Z

333

The Sun as an X-Ray Star. III. Flares  

Science Journals Connector (OSTI)

In previous works we have developed a method to convert solar X-ray data, collected with the Yohkoh/SXT, into templates of stellar coronal observations. Here we apply the method to several solar flares, for comparison with stellar X-ray flares. Eight flares, from weak (GOES class C5.8) to very intense ones (X9) are selected as representative of the flaring Sun. The emission measure distribution versus temperature, EM(T), of the flaring regions is derived from Yohkoh/SXT observations in the rise, peak, and decay of the flares. The EM(T) is rather peaked and centered around T ? 107 K for most of the time. Typically, it grows during the rise phase of the flare, and then it decreases and shifts toward lower temperatures during the decay, more slowly if there is sustained heating. The most intense flare we studied shows emission measure even at very high temperatures (T ? 108 K). Time-resolved X-ray spectra both unfiltered and filtered through the instrumental responses of the nonsolar instruments ASCA/SIS and ROSAT/PSPC are then derived. Synthesized ASCA/SIS and ROSAT/PSPC spectra are generally well fitted with single thermal components at temperatures close to that of the EM(T) maximum, albeit two thermal components are needed to fit some flare decays. ROSAT/PSPC spectra show that solar flares are in a 2 orders of magnitude flux range (106-108 ergs cm-2 s-1) and a narrow PSPC hardness ratio range, however, higher than that of typical nonflaring solar-like stars.

F. Reale; G. Peres; S. Orlando

2001-01-01T23:59:59.000Z

334

X-Ray Imaging Crystal Spectrometer for Extended X-Ray Sources  

SciTech Connect

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

335

X-Ray Source Based on the Parametric X-Rays  

E-Print Network (OSTI)

Prospects of parametric x-rays (PXR) application for the development of a tuneable quasi-monochromatic x-ray source for medical imaging are discussed. Analysis of basic requirements for electron accelerator shows that it must be relatively low-energy and high-current linac. In comparison with known ultra-relativistic cases, at low energies PXR properties will be modified to a great extent by multiple scattering of the electrons. PXR intensity dependence on target thickness and beam energy are calculated taking multiple scattering into account. It is concluded that PXR source based on real medical accelerators is feasible and can provide x-ray flux needful for obtaining high quality medical images.

Alexander Lobko; Olga Lugovskaya

2005-09-02T23:59:59.000Z

336

Apparatus for monitoring X-ray beam alignment  

DOE Patents (OSTI)

A self-contained, hand-held apparatus is provided for minitoring alignment of an X-ray beam in an instrument employing an X-ray source. The apparatus includes a transducer assembly containing a photoresistor for providing a range of electrical signals responsive to a range of X-ray beam intensities from the X-ray beam being aligned. A circuit, powered by a 7.5 VDC power supply and containing an audio frequency pulse generator whose frequency varies with the resistance of the photoresistor, is provided for generating a range of audible sounds. A portion of the audible range corresponds to low X-ray beam intensity. Another portion of the audible range corresponds to high X-ray beam intensity. The transducer assembly may include an a photoresistor, a thin layer of X-ray fluorescent material, and a filter layer transparent to X-rays but opaque to visible light. X-rays from the beam undergoing alignment penetrate the filter layer and excite the layer of fluorescent material. The light emitted from the fluorescent material alters the resistance of the photoresistor which is in the electrical circuit including the audio pulse generator and a speaker. In employing the apparatus, the X-ray beam is aligned to a complete alignment by adjusting the X-ray beam to produce an audible sound of the maximum frequency.

Steinmeyer, Peter A. (Arvada, CO)

1991-10-08T23:59:59.000Z

337

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

338

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.

339

Installation of soft X-ray array diagnostics and its application to tomography reconstruction using synthetic KSTAR X-ray images  

SciTech Connect

Four-array system of soft X-ray diagnostics was installed on KSTAR tokamak. Each array has 32 viewing chords of two photo-diode array detectors with spatial resolution of 2 cm. To estimate signals from the soft X-ray radiation power, typical n{sub e}, T{sub e}, and argon impurity line radiation profiles in KSTAR are chosen. The photo-diodes were absolutely calibrated as a function of the incident photon energy in 2–40 keV range with a portable X-ray tube. Two-dimensional T{sub e} image properties by multi-energy method were simulated and visualized with six combinations of beryllium filter sets within the dynamic range of signal ratio.

Lee, Seung Hun; Jang, Juhyeok; Hong, Joohwan; Jang, Siwon; Choe, Wonho, E-mail: wchoe@kaist.ac.kr [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Impurity and Edge Research Center, Daejeon 305-701 (Korea, Republic of); Pacella, D.; Romano, A.; Gabellieri, L. [Associazione Euratom-ENEA sulla Fusione, C.R. Frascati 00044 (Italy); Kim, Junghee [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Major of Nuclear Fusion and Plasma Science Department, Korea University of Science and Technology, Daejeon 305-350 (Korea, Republic of)

2014-11-15T23:59:59.000Z

340

The constellation X-ray mission  

Science Journals Connector (OSTI)

The Constellation-X mission is a large collecting area X-ray facility emphasizing observations at high spectral resolution (E/?E?300–3000) while covering a broad energy band (0.25–40 keV). This mission will achieve a factor of 100 increased sensitivity over current capabilities and is optimized to observe the effects of extreme gravity close to black holes and test models for the formation of large scale structure in the Universe. It is apart of NASA’s strategic plan for launch towards the end of the first decade of the 21st century.

N. E. White; H. Tananbaum

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

RYLLA. [X-ray transport code  

SciTech Connect

This paper describes a computer code, RYLLA, which models the deposition of x-rays into thin metal slabs, and transports the resulting photoelectrons, finding the distribution of electrons leaving the slab from both the front and back surfaces. The slab must be homogeneous, but can contain a mixture of up to 5 different elements. Due to the short electron mean free path at low electron energies, RYLLA should be used only for studying thin slabs, roughly < 100 mg/cm/sup 2/ for low Z metals, and < 10 mg/cm/sup 2/ for high Z metals. X-ray energies should be in the range of 1 to 150 keV, as they are deposited only via photoionization and Compton scattering processes. Following photoionization, a hole exists in the electron cloud of the absorbing atom. This fills either by Auger or fluoresence, resulting in lower energy holes which are also filled. Fluoresence photons are transported and absorbed in the same manner as the primary photons, except that they are isotropically produced. Once all photons have been transported and absorbed, and all holes have been filled, a space- and energy-dependent electron source spectrum has been obtained. This is used in a discrete ordinate expansion solution of the 1-D transport equation, which gives the output electron spectra at the two slab surfaces. This paper discusses both the physics and coding of RYLLA. Examples of user input are given, as are some comparisons with other codes.

Hyde, R.A.

1983-06-08T23:59:59.000Z

342

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

343

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers.  

SciTech Connect

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar{reg_sign} or Twaron{reg_sign}.

Parrot, I. M. [Institut Laue-Langevin (ILL); Urban, Volker S [ORNL; Gardner, K. H. [DuPont Experimental Station; Forsyth, V. T. [Institut Laue Langevin and Keele University

2005-04-01T23:59:59.000Z

344

Neutron and X-Ray Studies of Advanced Materials V: CENTENNIAL  

SciTech Connect

In 2012 the diffraction community will celebrate 100 years since the prediction of X-ray diffraction by M. Laue, and following his suggestion the first beautiful diffraction experiment by W. Friedrich and P. Knipping. The significance of techniques based on the analysis of the diffraction of X-rays, neutrons, electrons and Mossbauer photons discovered later, has continued to increase in the past 100 years. The aim of this symposium is to provide a forum for discussion of using state-of-the-art neutron and X-ray scattering techniques for probing advanced materials. These techniques have been widely used to characterize materials structures across all length scales, from atomic to nano, meso, and macroscopic scales. With the development of sample environments, in-situ experiments, e.g., at temperatures and applied mechanical load, are becoming routine. The development of ultra-brilliant third-generation synchrotron X-ray sources, together with advances in X-ray optics, has created intense X-ray microbeams, which provide the best opportunities for in-depth understanding of mechanical behavior in a broad spectrum of materials. Important applications include ultra-sensitive elemental detection by X-ray fluorescence/absorption and microdiffraction to identify phase and strain with submicrometer spatial resolution. X-ray microdiffraction is a particularly exciting application compared with alternative probes of crystalline structure, orientation and strain. X-ray microdiffraction is non-destructive with good strain resolution, competitive or superior spatial resolution in thick samples, and with the ability to probe below the sample surface. Advances in neutron sources and instrumentation also bring new opportunities in neutron scattering research. In addition to characterizing the structures, neutrons are also a great tool for elucidating the dynamics of materials. Because neutrons are highly penetrating, neutrons have been used to map stress in engineering systems. Neutrons have also played a vital role in our understanding of the magnetism and magnetic properties. Specialized instruments have been built to gain physical insights of the fundamental mechanisms governing phase transformation and mechanical behaviors of materials. The application of those techniques, in combination with theoretical simulations and numerical modeling, will lead to major breakthroughs in materials science in the foreseeable future that will contribute to the development of materials technology and industrial innovation.

Spanos, George

2012-05-01T23:59:59.000Z

345

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

SciTech Connect

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

Jianwei Miao

2011-04-18T23:59:59.000Z

346

Learning to Apply Metrology Principles to the Measurement of X-ray Intensities in the 500 eV to 110 keV Energy Range  

SciTech Connect

National Security Technologies, LLC (NSTec), Livermore Operations, has two optical radiation calibration laboratories accredited by “the National Voluntary Laboratories Accreditation Program (NVLAP) which is the accrediting body of” the National Institute of Standards and Technology (NIST), and is now working towards accreditation for its X-ray laboratories. NSTec operates several laboratories with X-ray sources that generate X-rays in the energy range from 50 eV to 115 keV. These X-ray sources are used to characterize and calibrate diagnostics and diagnostic components used by the various national laboratories, particularly for plasma analysis on the Lawrence Livermore National Laboratory (LLNL) National Ignition Facility (NIF). Because X-ray photon flux measurement methods that can be accredited, i.e., traceable to NIST, have not been developed for sources operating in these energy ranges, NSTec, NIST, and the National Voluntary Accreditation Program (NVLAP) together have defined a path toward the development and validation of accredited metrology methods for X-ray energies. The methodology developed for the high energy X-ray (HEX) Laboratory was NSTec’s starting point for X-ray metrology accreditation and will be the basis for the accredited processes in the other X-ray laboratories. This paper will serve as a teaching tool, by way of this example using the NSTec X-ray sources, for the process and methods used in developing an accredited traceable metrology.

Haugh, M. J.; Pond, T.; Silbernagel, C.; Torres, P.; Marlett, K.; Goldin, F.; Cyr, S.

2011-02-08T23:59:59.000Z

347

Development of procedures for refurbishing x-ray optics at the Advanced Light Source  

E-Print Network (OSTI)

Development of procedures for refurbishing x-ray optics atpractical and robust procedures for refurbishing x-ray

Yashchuk, Valeriy V.

2013-01-01T23:59:59.000Z

348

Improved backscatter x-ray detection for anti-terrorist applications  

SciTech Connect

Currently the most common method to determine the contents of a package suspected of containing an explosive device is to use transmission radiography. This technique requires that an x-ray source and film be placed on opposite sides of the package. This poses a problem if the package is placed so that only one side is accessible, such as against a wall. There is also a threat to personnel and property since explosive devices may be booby trapped. The authors have developed a method to x-ray a package using backscattered x-rays based on similar work for landmine detection. This procedure eliminates the use of film behind the target. All of the detection is done from the same side as the source. Backscatter experiments at Sandia National Laboratories have been conducted on mock bombs in packages. They are able to readily identify the bomb components. The images that are obtained in this procedure are done in real time and the image is displayed on a computer screen. Preliminary experiments have also imaged objects within or behind a wall. They are currently using a scanning x-ray source and scintillating plastic detectors. It can take several hours to image a briefcase size object. This time could be reduced if better x-ray detection methods could be used. They have looked at using pinhole photography and CCD cameras to reduce this time.

Shope, S.L.; Lockwood, G.J.; Selph, M.M.; Wehlburg, J.C.

1999-12-01T23:59:59.000Z

349

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

350

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

351

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.

352

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.

353

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.

354

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.

355

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

356

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

357

Density gradient free electron collisionally excited X-ray laser  

DOE Patents (OSTI)

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

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

1989-01-01T23:59:59.000Z

358

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

359

Formation of microbeam using tabletop soft X-ray laser  

Science Journals Connector (OSTI)

An X-ray microprobe with a sub-micron size beam and high intensity can provide X-ray analyses with a remarkable spatial resolution. We have performed focusing of an X-ray laser output into a sub-micron beam for the first time. In our experiment, an X-ray laser of Li-like Al 3d–4f transition at 15.47 nm was delivered from an unstable cavity consisting of a concave mirror and a flat mirror with a square orifice of 100×100 ?m in size. The beam from the orifice was then focused by using a Schwarzschild mirror coated with a Mo/Si multilayer. An X-ray beam size with a diameter of about 0.45 ?m and an estimated photon number of about 2×106 photons per shot was achieved. Such sources could be well suited for the realization of X-ray microprobes.

Tadayuki Ohchi; Naohiro Yamaguchi; Chiemi Fujikawa; Tamio Hara

1999-01-01T23:59:59.000Z

360

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,

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

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.

362

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

SciTech Connect

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

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

2007-08-01T23:59:59.000Z

363

Backscatter x-ray development for space vehicle thermal protection systems  

SciTech Connect

The Backscatter X-Ray (BSX) imaging technique is used for various single sided inspection purposes. Previously developed BSX techniques for spray-on-foam insulation (SOFI) have been used for detecting defects in Space Shuttle External Tank foam insulation. The developed BSX hardware and techniques are currently being enhanced to advance Non-Destructive Evaluation (NDE) methods for future space vehicle applications. Various Thermal Protection System (TPS) materials were inspected using the enhanced BSX imaging techniques, investigating the capability of the method to detect voids and other discontinuities at various locations within each material. Calibration standards were developed for the TPS materials in order to characterize and develop enhanced BSX inspection capabilities. The ability of the BSX technique to detect both manufactured and natural defects was also studied and compared to through-transmission x-ray techniques. The energy of the x-ray, source to object distance, angle of x-ray, focal spot size and x-ray detector configurations were parameters playing a significant role in the sensitivity of the BSX technique to image various materials and defects. The image processing of the results also showed significant increase in the sensitivity of the technique. The experimental results showed BSX to be a viable inspection technique for space vehicle TPS systems.

Bartha, Bence B.; Hope, Dale; Vona, Paul; Born, Martin; Corak, Tony [USA NDE, United Space Alliance, Cape Canaveral, FL 32920 (United States)

2011-06-23T23:59:59.000Z

364

X-ray Pinhole Camera Measurements  

SciTech Connect

The rod pinch diode is made up of a cathode plate and a small diameter anode rod that extends through the cathode hole. The anode is charged positively. The rod tip is made of a high-z material which is chosen for its bremsstrahlung efficiency. When the diode is pulsed it produces an intense x-ray source used for pulsed radiography. The baseline or reference diode consists of a 0.75 mm diameter Tungsten (W) tapered anode rod which extends 10 mm through a 9 mm diameter 3 mm thick aluminum (Al) aperture. The majority of the current in the electron beam is created on the edges of the cathode aperture and when properly configured, the electrons will self insulate, travel down the extension of the rod, and pinch onto the tip of the rod. In this presentation, performance of hybrid diodes will be compared with the baseline diode.

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

2013-06-20T23:59:59.000Z

365

Nonlinear optics with focused x-ray lasers  

SciTech Connect

We have investigated the possibility of focusing x-ray lasers with the use of multilayered mirrors or zone plates. The results indicate that x-ray intensities as high as 10{sup 14} W/cm{sup 2} can be achieved by focusing saturated Ne-like x-ray lasers. These intensities should be adequate for studying nonlinear optical phenomena. 9 refs., 2 figs.

DaSilva, L.B.; Muendel, M.H.; Falcone, R.W.; Fields, D.J.; Kortright, J.B.; MacGowan, B.J.; Matthews, D.L.; Mrowka, S.; Shimkaveg, G.M.; Trebes, J.E.

1990-12-12T23:59:59.000Z

366

The first X-ray diffraction measurements on Mars  

Science Journals Connector (OSTI)

The X-ray diffraction/X-ray fluorescence instrument CheMin on the Curiosity rover is a shoebox-sized device using transmission geometry and an energy-discriminating CCD detector. The instrument has returned the first X-ray diffraction data for soil and drilled samples from Mars outcrops, revealing a suite of primary basaltic minerals, amorphous components and varied hydrous alteration products including phyllosilicates.

Bish, D.

2014-10-21T23:59:59.000Z

367

On X-Ray Waveguiding in Nanochannels: Channeling Formalism  

E-Print Network (OSTI)

The question on X-ray extreme focusing (smallest reachable spot size) brings us to the idea for using the wave features of X-ray propagation in media. As known, wave features are revealed at propagation in ultra-narrow collimators as well as at glancing reflection from smooth flat and/or strongly curved surfaces. All these phenomena can be described within the general formalism of X-ray channeling.

S. B. Dabagov

2006-11-20T23:59:59.000Z

368

THE GEODESIC X-RAY TRANSFORM WITH FOLD CAUSTICS The ...  

E-Print Network (OSTI)

Aug 28, 2012 ... THE GEODESIC X-RAY TRANSFORM WITH FOLD CAUSTICS. PLAMEN STEFANOV AND GUNTHER UHLMANN. ABSTRACT. We give a ...

2012-08-28T23:59:59.000Z

369

Inelastic X-ray and Nuclear Resonant Scattering  

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

... Search About User Information News & Events Science & Education Beamlines Divisions Argonne Home > Advanced Photon Source > Inelastic X-ray and Nuclear Resonant Scattering...

370

Advances in X-Ray Diagnostics of Diesel Fuel Sprays  

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

Recent advances in high-speed X-ray imaging has shown several distinct behaviors of commercial fuel injectors that cannot be seen with more conventional techniques.

371

New intraoral x-ray fluorographic imaging for dentistry  

SciTech Connect

A new dental x-ray fluorographic unit has been developed. This unit is composed of small intraoral x-ray tube, a compact x-ray image intensifier, and a high-resolution TV system. The purposes for developing this equipment were to (1) directly observe the tooth during endodontic procedures and (2) reduce x-ray exposure to the patient and the dentist. The radiation exposure can be reduced to about 1/600 the exposure used with conventional dental film. In clinical trials, a satisfactory fluorographic dental image for endodontic treatment was obtained with this new device.

Higashi, T.; Osada, T.; Aoyama, W.; Iguchi, M.; Suzuki, S.; Kanno, M.; Moriya, K.; Yoshimura, M.; Tusuda, M.

1983-06-01T23:59:59.000Z

372

Normal incidence x-ray mirror for chemical microanalysis  

DOE Patents (OSTI)

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

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

1987-08-05T23:59:59.000Z

373

Self-terminating diffraction gates femtosecond X-ray nanocrystallograp...  

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

Self-terminating diffraction gates femtosecond X-ray nanocrystallography measurements Authors: Barty, A., Caleman, C., Aquila, A., Timneanu, N., Lomb, L., White, T. A., Andreasson,...

374

High intensity x-ray source using liquid gallium target  

DOE Patents (OSTI)

A high intensity x-ray source that uses a flowing stream of liquid gallium as a target with the electron beam impinging directly on the liquid metal.

Smither, Robert K. (Hinsdale, IL); Knapp, Gordon S. (Cupertino, CA); Westbrook, Edwin M. (Chicago, IL); Forster, George A. (Westmont, IL)

1990-01-01T23:59:59.000Z

375

X-ray Diffuse Scattering Measurements of Nucleation Dynamics...  

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

X-ray Diffuse Scattering Measurements of Nucleation Dynamics at Femtosecond Resolution Real-time measurement and control of the non-equilibrium properties of materials represents...

376

XRMS: X-Ray Spectroscopy of Magnetic Solids  

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

XRMS: X-Ray Spectroscopy of Magnetic Solids October 22-23, 2011 SLAC National Accelerator Laboratory, Menlo Park, CA More information...

377

X-ray absorption fine structure and magnetization characterization...  

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

characterization of the metallic Co component in Co-doped ZnO thin films . X-ray absorption fine structure and magnetization characterization of the metallic Co...

378

Energy Dispersive X-ray Fluorescence Analysis of Sulfur in Biomass  

Science Journals Connector (OSTI)

An energy dispersive X-ray fluorescence (ED-XRF) spectroscopy method was developed to analyze low ppm level sulfur (S) in biomass feedstocks and in subsequent residues from pretreatment reactions. ... Representative biomass feedstocks and pretreatment residues were analyzed for S. ... The goal of this project was to determine whether an energy dispersive X-ray fluorescence (ED-XRF) spectroscopy method is effective in conducting sulfur analysis of woody biomass feedstocks at an appropriately useful sensitivity, especially when used to effectively monitor the extent of sulfur removal after biomass pretreatment reactions. ...

J. Michael Robinson; Staci R. Barrett; Kevin Nhoy; Rajesh K. Pandey; Joseph Phillips; Oscar M. Ramirez; Richard I. Rodriguez

2009-03-06T23:59:59.000Z

379

Phase imaging of magnetic nanostructures using resonant soft x-ray holography  

Science Journals Connector (OSTI)

We demonstrate phase imaging by means of resonant soft x-ray holography. Our holographic phase-contrast method utilizes the strong energy-dependence of the refractive index at a characteristic x-ray absorption resonance. The general concept is shown by using a Co?Pd multilayer sample which exhibits random nanosized magnetic domains. By tuning below the Co L-edge resonance, our quantitative and spectroscopic phase method allows high-contrast imaging of nanoscale electronic and magnetic order while increasing the probing depth and decreasing the radiation dose by an order of magnitude. The complex refractive index is quantitatively obtained through the interference between resonant and nonresonant scattering.

A. Scherz; W. F. Schlotter; K. Chen; R. Rick; J. Stöhr; J. Lüning; I. McNulty; Ch. Günther; F. Radu; W. Eberhardt; O. Hellwig; S. Eisebitt

2007-12-17T23:59:59.000Z

380

Reconstructing the projected gravitational potential of Abell 1689 from X-ray measurements  

E-Print Network (OSTI)

Context. Galaxy clusters can be used as cosmological probes, but to this end, they need to be thoroughly understood. Combining all cluster observables in a consistent way will help us to understand their global properties and their internal structure. Aims. We provide proof of the concept that the projected gravitational potential of galaxy clusters can directly be reconstructed from X-ray observations. We also show that this joint analysis can be used to locally test the validity of the equilibrium assumptions in galaxy clusters. Methods. We used a newly developed reconstruction method, based on Richardson-Lucy deprojection, that allows reconstructing projected gravitational potentials of galaxy clusters directly from X-ray observations. We applied this algorithm to the well-studied cluster Abell 1689 and compared the gravitational potential reconstructed from X-ray observables to the potential obtained from gravitational lensing measurements. [...] Results. Assuming spherical symmetry and hydrostatic equili...

Tchernin, Celine; Meyer, Sven; Sarli, Eleonora; Eckert, Dominique; Bartelmann, Matthias

2015-01-01T23:59:59.000Z

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


381

The effect of accretion on the measurement of neutron star mass and radius in the low-mass X-ray binary 4U 1608-52  

E-Print Network (OSTI)

Spectral measurements of thermonuclear (type-I) X-ray bursts from low mass X-ray binaries have been used to measure neutron star (NS) masses and radii. A number of systematic issues affect such measurements and have raised concerns as to the robustness of the methods. We present analysis of the X-ray emission from bursts observed from 4U 1608-52 at various persistent fluxes. We find a strong dependence of the burst properties on the flux and spectral hardness of the persistent emission before burst. Bursts occurring during the low-accretion rate (hard) state exhibit evolution of the black body normalisation consistent with the theoretical predictions of NS atmosphere models. However, bursts occurring during the high-accretion rate (soft) state show roughly constant normalisation, which is inconsistent with the NS atmosphere models and therefore these bursts cannot be easily used to determine NS parameters. We analyse the hard-state burst to put the lower limit on the neutron star radius in 4U 1608-52 of 13 km...

Poutanen, Juri; Kajava, Jari J E; Latvala, Outi-Marja; Galloway, Duncan; Kuulkers, Erik; Suleimanov, Valery

2014-01-01T23:59:59.000Z

382

SOFT X-RAY EMISSION LINES OF S VII-S XIV IN PROCYON  

SciTech Connect

Observational data for cool star Procyon available from the Chandra Data Public Archive are co-added and analyzed with as high a signal-to-noise ratio as possible. The soft X-ray emission lines of highly charged sulfur ions (S VII-S XV) are investigated in the 30-80 A range. A collisional-radiative model is constructed to predict line emissivities of sulfur ions using updated excitation data from the R-matrix method. Theoretical line fluxes and line intensity ratios are calculated, and theoretical spectra are constructed with a Gaussian profile with a line width of 0.06 A. By comparing predicted emission lines with observed ones, several strong emission lines are identified for the first time. Some misassignments of lines in previous works are also corrected. By comparing our results with those from the Chianti (v6) model, this work provides insight into the completeness and accuracy of the atomic data of sulfur ions in the Chianti (v6) database.

Li, F.; Liang, G. Y.; Zhao, G., E-mail: gyliang@bao.ac.cn, E-mail: gzhao@bao.ac.cn [Also at National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China. (China)

2013-01-01T23:59:59.000Z

383

Practical X-ray Crystallography, BIOS535 Spring 2010, second half of the spring semester, starting March 9  

E-Print Network (OSTI)

16 Lecture: X-ray and radiation safety Lab: Preliminary crystal analysis; High throughput application of crystallographic methods and use of equipment and software. Very class will be started

Tao, Yizhi Jane

384

Structural defects and the electronic structure of zirconium hydrides: x-ray emission spectra and quantum chemical calculations  

Science Journals Connector (OSTI)

X-ray emission spectroscopy and the Green function LMTO band method was used to study the effect of structural defects in the hydrogen sublattice on the electronic structure and chemical bonding in ZrH2.

A. L. Ivanovskii; Yu. M. Yarmoshenko; A. Ya. Kupryazhkin…

385

Theoretical Backgrounds of the Statistical Methods. Basic Concepts of Probability and Statistics.  

Science Journals Connector (OSTI)

Theoretical Backgrounds of the Statistical Methods. ... Basic Concepts of Probability and Statistics. ...

Henry Scheffe

1951-01-01T23:59:59.000Z

386

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Lensless Imaging of Whole Biological Cells with Soft X-Rays Print A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

387

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Lensless Imaging of Whole Biological Cells with Soft X-Rays Print A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

388

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Lensless Imaging of Whole Biological Cells with Soft X-Rays Print A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

389

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Lensless Imaging of Whole Biological Cells with Soft X-Rays Print A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

390

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Lensless Imaging of Whole Biological Cells with Soft X-Rays Print A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

391

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Lensless Imaging of Whole Biological Cells with Soft X-Rays Print A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

392

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Lensless Imaging of Whole Biological Cells with Soft X-Rays Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Wednesday, 26 May 2010 00:00 A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

393

High Quality Image of Biomedical Object by X-ray Refraction Based Contrast Computed Tomography  

SciTech Connect

Recently we have developed a new Computed Tomography (CT) algorithm for refraction contrast that uses the optics of diffraction-enhanced imaging. We applied this new method to visualize soft tissue which is not visualized by the current absorption based contrast. The meaning of the contrast that appears in refraction-contrast X-ray CT images must be clarified from a biologic or anatomic point of view. It has been reported that the contrast is made with the specific gravity map with a range of approximately 10 {mu}arc sec. However, the relationship between the contrast and biologic or anatomic findings has not been investigated, to our knowledge. We compared refraction-contrast X-ray CT images with microscopic X-ray images, and we evaluated refractive indexes of pathologic lesions on phase-contrast X-ray CT images. We focused our attenuation of breast cancer and lung cancer as samples. X-ray refraction based Computed Tomography was appeared to be a pathological ability to depict the boundary between cancer nest and normal tissue, and inner structure of the disease.

Hashimoto, E. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Maksimenko, A.; Hirano, K.; Hyodo, K. [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Sugiyama, H. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Shimao, D. [Department of Health Sciences, Ibaraki prefectural University of Health Sciences, 4669-2Ami, Ami, Inashiki, Ibaraki, 300-0394 (Japan); Nishino, Y.; Ishikawa, T. [RIKEN Harima Institute, 1-1-1 Kouto, Mikazuki, Sayo, Hyogo, 679-5148 (Japan); Yuasa, T. [Department of Bio-system Engineering, Faculty of Engineering Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510 (Japan); Ichihara, S. [Dept. of Path., Nagoya Med. Center, Nat. Hospital Organization, Naka-ku, Nagoya 460-0001 (Japan); Arai, Y. [Matsumoto Dental University, 1980 Hirooka, Shiojiri, Nagano (Japan); Ando, M. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Inst. of Sci. and Tech., Tokyo Univ. of Science, Yamasaki 2641, Noda, Chiba 278-8510 (Japan)

2007-01-19T23:59:59.000Z

394

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

SciTech Connect

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

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

2014-05-15T23:59:59.000Z

395

Effect of anode shape on pinch structure and X-ray emission of plasma focus device  

Science Journals Connector (OSTI)

Abstract The effect of anode shapes on pinch structure and X-ray emission of plasma focus device operated with cylindrical, diverging, oval and converging anode tips is reported. The pinch structure in the radial compression phase has been investigated by employing a triple pinhole camera. It has been observed that pinch structure as well as the X-ray emission of PF device strongly depends upon anode tip designs. For the first time the studies were carried out in two new shapes of anode tips that is the oval and the divergent one. It has been observed that the oval and diverging anode tips are more conducive for the formation of instabilities and hotspot generation. The studies of X-ray emission were also carried out by employing three channels of a p-i-n diode X-ray spectrometer in entire anode designs to corroborate the results of a triple pinhole camera. Additionally, the effective hard X-ray photon energy was also estimated by the radiography method for all the anode tip designs, which indirectly provide a qualitative idea of the generation of induced accelerating field in the pinched column during compression.

N. Talukdar; N.K. Neog; T.K. Borthkur

2013-01-01T23:59:59.000Z

396

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Lensless Imaging of Whole Biological Cells with Soft X-Rays Print A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

397

Lensless Imaging of Whole Biological Cells with Soft X-Rays  

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

Lensless Imaging of Whole Biological Cells with Soft X-Rays Print Lensless Imaging of Whole Biological Cells with Soft X-Rays Print A team of scientists has used x-ray diffraction microscopy at ALS Beamline 9.0.1 to make images of whole yeast cells, achieving the highest resolution-11 to 13 nanometers (billionths of a meter)-ever obtained with this method for biological specimens. Their success indicates that full 3-D tomography of whole cells at equivalent resolution should soon be possible. The National Center for X-Ray Tomography at ALS Beamline 2.1 images whole, frozen hydrated cells in 3-D (see highlight "Imaging Antifungal Drug Molecules in Action using Soft X-Ray Tomography"). Large numbers of cells can currently be processed in a short time at resolutions of 40 to 60 nanometers, but the ability to increase resolution to the 10-nanometer range would enhance research capabilities in both biology and materials sciences.

398

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

E-Print Network (OSTI)

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

Thomas J. Maccarone

2005-03-31T23:59:59.000Z

399

Isotropic star in low-mass X-ray binaries and X-ray pulsars  

E-Print Network (OSTI)

We present a model for compact stars in the low mass X-ray binaries(LMXBs) and X-ray pulsars using a metric given by John J. Matese and Patrick G. Whitman \\citep{Matese and Whitman1980}. Here the field equations are reduced to a system of two algebraic equations considering the isotropic pressure. Compact star candidates 4U 1820-30(radius=10km) in LMXBs, and Her X-1(radius=7.7km), SAX J 1808.4-3658(SS1)(radius=7.07km) and SAX J 1808.4-3658(SS2)(radius=6.35km) in X-ray pulsars satisfy all the energy conditions, TOV-equation and stability condition. From our model, we have derived mass($M$), central density($\\rho_{0}$), suface density($\\rho_{b}$), central pressure($p_{0}$), surface pressure($p_{b}$) and surface red-shift($Z_{s}$) of the above mentioned stars, which are very much consistant with the observed/reported datas\\citep{N. K. Glendenning1997,Gondek2000}. We have also observe the adiabatic index($\\gamma$>4/3) of the above steller objects.

Mehedi Kalam; Sk. Monowar Hossein; Sajahan Molla

2014-10-01T23:59:59.000Z

400

In-situ stress analysis with X-Ray diffraction for yield locus characterization of sheet metals  

SciTech Connect

A main problem in the field of sheet metal characterization is the inhomogeneous plastic deformation in the gauge regions of specimens which causes the analytically calculated stresses to differ from the sought state of stress acting in the middle of the gauge region. To overcome this problem, application of X-Ray diffraction is analyzed. For that purpose a mobile X-ray diffractometer and an optical strain measurement system are mounted on a universal tensile testing machine. This enables the recording of the whole strain and stress history of a material point. The method is applied to uniaxial tension tests, plane strain tension tests and shear tests to characterize the interstitial free steel alloy DC06. The applicability of the concepts of stress factors is verified by uniaxial tension tests. The experimentally obtained values are compared with the theoretical values calculated with crystal elasticity models utilizing the orientation distribution functions (ODF). The relaxation problem is addressed which shows itself as drops in the stress values with the strain kept at a constant level. This drop is analyzed with elasto-viscoplastic material models to correct the measured stresses. Results show that the XRD is applicable to measure the stresses in sheet metals with preferred orientation. The obtained yield locus is expressed with the Yld2000–2D material model and an industry oriented workpiece is analyzed numerically. The comparison of the strain distribution on the workpiece verifies the identified material parameters.

Güner, A.; Tekkaya, A. E. [Institute of Forming Technology and Lightweight Construction, TU Dortmund University, Baroper Str. 301, 44227 Dortmund (Germany); Zillmann, B.; Lampke, T. [Institute of Materials Science and Engineering, Chemnitz University of Technology, Erfenschlager Strasse 73 D-09125 Chemnitz (Germany)

2013-12-16T23:59:59.000Z

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401

Burning plasmas with ultrashort soft-x-ray flashing  

SciTech Connect

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

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

2012-07-15T23:59:59.000Z

402

Core and Valence Excitations in Resonant X-ray Spectroscopy using Restricted Excitation Window Time-dependent Density Functional Theory  

SciTech Connect

We report simulations of X-ray absorption near edge structure (XANES), resonant inelastic X-ray scattering (RIXS) and 1D stimulated X-ray Raman spectroscopy (SXRS) signals of cysteine at the oxygen, nitrogen and sulfur K and L2,3 edges. The simulated XANES signals from the restricted window time-dependent density functional theory (REW-TDDFT) and the static exchange (STEX) method are compared with experiments, showing that REW-TDDFT is more accurate and computationally less expensive than STEX. Simulated RIXS and 1D SXRS signals from REW-TDDFT give some insights on the correlation of different excitations in the molecule.

Zhang, Yu; Biggs, Jason D.; Healion, Daniel; Govind, Niranjan; Mukamel, Shaul

2012-11-21T23:59:59.000Z

403

Investigating Biological Matter with Theoretical Nuclear Physics Methods  

E-Print Network (OSTI)

The internal dynamics of strongly interacting systems and that of biomolecules such as proteins display several important analogies, despite the huge difference in their characteristic energy and length scales. For example, in all such systems, collective excitations, cooperative transitions and phase transitions emerge as the result of the interplay of strong correlations with quantum or thermal fluctuations. In view of such an observation, some theoretical methods initially developed in the context of theoretical nuclear physics have been adapted to investigate the dynamics of biomolecules. In this talk, we review some of our recent studies performed along this direction. In particular, we discuss how the path integral formulation of the molecular dynamics allows to overcome some of the long-standing problems and limitations which emerge when simulating the protein folding dynamics at the atomistic level of detail.

Pietro Faccioli

2011-08-25T23:59:59.000Z

404

Response Time Measurements of the NIF DANTE XRD-31 X-Ray Diodes (Pre-print)  

SciTech Connect

The XRD-31 is a fast, windowless X-ray vacuum photodiode developed by EG&G. It is currently the primary fast X-ray detector used to diagnose the X-rays on NIF and OMEGA on the multichannel DANTE spectrometer. The XRD-31 has a dynamic range of less than 1e-12 amps to more than 10 amps. A technique is described to measure the impulse response of the diodes to a 150 fs pulse of 200 nm laser light and a method to calculate the “risetime” for a square pulse and compare it with the computed electron transit time from the photocathode to the anode. Measured response time for 5 XRD-31s assembled in early 2004 was 149.7 ps +-2.75 ps.

Don Pellinen and Michael Griffin

2009-01-23T23:59:59.000Z

405

X-ray driven channeling acceleration in crystals and carbon nanotubes  

SciTech Connect

Acceleration of particles channeling in a crystal by means of diffracted x-rays via Bormann anomalous transmission was conceived for heavy ions and muons by Tajima and Cavenago [Phys. Rev. Lett. 59, 1440 (1987)], which potentially offers an appreciably high field gradient on the order of GV/cm. The theoretical model of the high gradient acceleration has been studied in two kinds of atomic structure, crystals and carbon nanotubes (CNTs), with analytic calculations and electromagnetic eigenmode simulations. A range of acceleration gradients and cutoffs of the x-ray power (the lowest power limit to overcome the Bremsstrahlung radiation losses) are characterized in terms of the lattice constants, unit cell sizes, and photon energies. The parametric analysis indicates that the required x-ray power can be reduced to an order of megawatt by replacing crystals with CNTs. Eventually, the equivalent dielectric approximation of a multi-wall nanotube shows that 250–810 MeV muons can be synchronously coupled with x-rays of 0.65–1.32 keV in the accelerating structure.

Shin, Young-Min [Department of Physics, Northern Illinois Center for Accelerator and Detector Development (NICADD), Northern Illinois University, Dekalb, Illinois 60115 (United States) [Department of Physics, Northern Illinois Center for Accelerator and Detector Development (NICADD), Northern Illinois University, Dekalb, Illinois 60115 (United States); Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Still, Dean A.; Shiltsev, Vladimir [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)] [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)

2013-12-15T23:59:59.000Z

406

X-ray source assembly having enhanced output stability, and fluid stream analysis applications thereof  

DOE Patents (OSTI)

An x-ray source assembly and method of operation are provided having enhanced output stability. The assembly includes an anode having a source spot upon which electrons impinge and a control system for controlling position of the anode source spot relative to an output structure. The control system can maintain the anode source spot location relative to the output structure notwithstanding a change in one or more operating conditions of the x-ray source assembly. One aspect of the disclosed invention is most amenable to the analysis of sulfur in petroleum-based fuels.

Radley, Ian (Glenmont, NY); Bievenue, Thomas J. (Delmar, NY); Burdett, John H. (Charlton, NY); Gallagher, Brian W. (Guilderland, NY); Shakshober, Stuart M. (Hudson, NY); Chen, Zewu (Schenectady, NY); Moore, Michael D. (Alplaus, NY)

2008-06-08T23:59:59.000Z

407

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

SciTech Connect

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

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

2012-07-09T23:59:59.000Z

408

Digital real time radiography and X-ray computed tomography development at AWE plc  

SciTech Connect

Digital X-ray imaging promises many advantages over conventional film radiography. The technique collects images electronically thus eliminating X-ray film, chemicals and chemical waste. Many radiographs can be stored on an optical disk or CD ROM and can be retrieved quickly and repeatedly using modern data archiving methods. Data can be transmitted electronically over local networks or the Internet for remote consultations. This paper discusses the development of a lens coupled digital radiography system currently being developed at AWE plc to examine high-density weapon components and sub-assemblies.

Tatum, Paul J. [Metallic Materials Business Area AWE plc, Reading Berkshire England RG7 4PR (United Kingdom)

1999-12-02T23:59:59.000Z

409

X-ray Phase Imaging Microscopy using a Fresnel Zone Plate and a Transmission Grating  

SciTech Connect

We report on a hard X-ray phase imaging microscopy (a phase-difference microscopy) that consists of an objective and a transmission grating. The simple optical system provides a quantitative phase image, and does not need a wave field mostly coherent on the objective. Our method has a spatial resolution almost same as that of the absorption contrast microscope image obtained by removing the grating. We demonstrate how our approach provides a phase image from experimentally obtained images. Our approach is attractive for easily appending a quantitative phase-sensitive mode to normal X-ray microscopes, and has potentially broad applications in biology and material sciences.

Yashiro, Wataru; Momose, Atsushi [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8561 (Japan); Takeuchi, Akihisa; Suzuki, Yoshio [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198 (Japan)

2010-06-23T23:59:59.000Z

410

Soft-x-ray-emission spectra of solid Kr and Xe  

Science Journals Connector (OSTI)

We present the first soft x-ray-emission spectra for solid Kr (4p-3d) and Xe (5p-4d) that are free of complicating satellite spectra. Monochromatic synchrotron-radiation excitation is used to suppress the satellites. The data are analyzed to determine the P3/2 bandwidth for both elements; these results are compared with both photoemission data and available theoretical calculations. Bandwidths are found to be larger than those predicted by most electronic structure calculations.

J. J. Jia; W. L. O’Brien; T. A. Callcott; Q. Y. Dong; J-E. Rubensson; D. R. Mueller; D. L. Ederer

1991-08-05T23:59:59.000Z

411

Accurate measurement of K x-ray intensities of elements with Z=79–82  

Science Journals Connector (OSTI)

Using high-resolution and high-efficiency high-purity Ge Gamma-X detectors, relative intensities of K x rays of elements with Z=79–82 have been very accurately (uncertainty ?1%) determined. Comparison of the data with other experimental works and theoretical calculations have been done. It is seen that a theory with the exchange effect taken into consideration is quite adequate to explain the radiative transition rates for the elements measured in the present work.

Binay Dasmahapatra and Anjali Mukherjee

1995-05-01T23:59:59.000Z

412

On the characterisation of a Bragg spectrometer with X-rays from an ECR source  

E-Print Network (OSTI)

Narrow X-ray lines from helium-like argon emitted from a dedicated ECR source have been used to determine the response function of a Bragg crystal spectrometer equipped with large area spherically bent silicon (111) or quartz (10$\\bar{1}$) crystals. The measured spectra are compared with simulated ones created by a ray-tracing code based on the expected theoretical crystal's rocking curve and the geometry of the experimental set-up.

Anagnostopoulos, D F; Gotta, D; Gruber, A; Indelicato, P J; Leoni, B; Fuhrmann, H; Simons, L M; Stingelin, L; Wasser, A; Zmeskal, J; Indelicato, Paul

2004-01-01T23:59:59.000Z

413

Combined energy dispersive EXAFS and x?ray diffraction  

Science Journals Connector (OSTI)

An in situ experiment to measure both x?ray absorption spectroscopy and x?ray diffraction of aurichalcite is described. The experiment uses position sensitive detectors to enable both data sets to be collected while the sample is slowly decomposed in air and then reduced in hydrogen. ?

A. J. Dent; M. P. Wells; R. C. Farrow; C. A. Ramsdale; G. E. Derbyshire; G. N. Greaves; J. W. Couves; J. M. Thomas

1992-01-01T23:59:59.000Z

414

Fresnel and refractive lenses for X-rays  

Science Journals Connector (OSTI)

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

B.X. Yang

1993-01-01T23:59:59.000Z

415

Shining Soft X-rays on Magnetic Structures  

Science Journals Connector (OSTI)

...2) demonstrate the power of x-ray magneto-optics in a synchroton study of single crystalline FePd layers, which provides...2) demonstrate the power of x-ray magneto-optics in a synchroton study of single crystalline FePd layers, which provides detailed...

Ulrich Hillebrecht

1999-06-25T23:59:59.000Z

416

Human genome sequencing with direct x-ray holographic imaging  

SciTech Connect

Direct holographic imaging of biological materials is widely applicable to the study of the structure, properties and action of genetic material. This particular application involves the sequencing of the human genome where prospective genomic imaging technology is composed of three subtechnologies, name an x-ray holographic camera, suitable chemistry and enzymology for the preparation of tagged DNA samples, and the illuminator in the form of an x-ray laser. We report appropriate x-ray camera, embodied by the instrument developed by MCR, is available and that suitable chemical and enzymatic procedures exist for the preparation of the necessary tagged DNA strands. Concerning the future development of the x-ray illuminator. We find that a practical small scale x-ray light source is indeed feasible. This outcome requires the use of unconventional physical processes in order to achieve the necessary power-compression in the amplifying medium. The understanding of these new physical mechanisms is developing rapidly. Importantly, although the x-ray source does not currently exist, the understanding of these new physical mechanisms is developing rapidly and the research has established the basic scaling laws that will determine the properties of the x-ray illuminator. When this x-ray source becomes available, an extremely rapid and cost effective instrument for 3-D imaging of biological materials can be applied to a wide range of biological structural assays, including the base-pair sequencing of the human genome and many questions regarding its higher levels of organization.

Rhodes, C.K.

1993-06-08T23:59:59.000Z

417

Twelfth National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

Twelfth National School on Neutron and X-ray Scattering June 12 � June 26, 2010 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne

Pennycook, Steve

418

National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

National School on Neutron and X-ray Scattering May 30 � June 13, 2009 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne

Pennycook, Steve

419

National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

15th National School on Neutron and X-ray Scattering August 10 - 24, 2013 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major Ridge National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang

420

Fourteenth National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

Fourteenth National School on Neutron and X-ray Scattering August 12 - 25, 2012 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major Ridge National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang

Pennycook, Steve

Note: This page contains sample records for the topic "theoretical methods x-ray" 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

Thirteenth National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

Thirteenth National School on Neutron and X-ray Scattering June 11 ­ June 25, 2011 at Argonne of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne

422

Neutron and X-ray Scattering Study of Magnetic Manganites  

E-Print Network (OSTI)

Neutron and X-ray Scattering Study of Magnetic Manganites Graeme Eoin Johnstone A Thesis submitted are performed using a variety of neutron scattering and x-ray scattering techniques. The electronic ground for analysing the results of the polarised neutron scattering experiment. There are a large number of people who

Boothroyd, Andrew

423

Sixteenth National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

Sixteenth National School on Neutron and X-ray Scattering June 14-28, 2014 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major's Neutron Scattering Science Division. Scientific Directors: Suzanne G.E. te Velthuis, Esen Ercan Alp

Pennycook, Steve

424

Tenth National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

Tenth National School on Neutron and X-ray Scattering September 24 - October 11, 2008 at Argonne of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne

Pennycook, Steve

425

X-ray spectra transmitted through Compton-thick absorbers  

E-Print Network (OSTI)

X-ray spectra transmitted through matter which is optically thick to Compton scattering are computed by means of Monte Carlo simulations. Applications to the BeppoSAX data of the Seyfert 2 galaxy in Circinus, and to the spectral modeling of the Cosmic X-ray Background, are discussed.

Giorgio Matt; Fulvio Pompilio; Fabio La Franca

1999-04-24T23:59:59.000Z

426

Laser Copper Plasma X-ray Source Debris Characterization  

E-Print Network (OSTI)

Laser Copper Plasma X-ray Source Debris Characterization A Thesis Presented by David Hurley 3, 2007 Vice President for Research and Dean of Graduate studies #12;Abstract Laser copper plasma for x-ray lithography. Copper debris in the form of vapor, ions, dust, and high-speed particles

Huston, Dryver R.

427

Millisecond oscillations during thermonuclear X-ray bursts  

E-Print Network (OSTI)

I analyze 68 oscillation trains detected in a search of 159 thermonuclear bursts from eight neutron star X-ray binaries observed with the Rossi X-ray Timing Explorer. I use all data that were public as of September 2001. ...

Muno, Michael Patrick, 1975-

2002-01-01T23:59:59.000Z

428

X rays following the alpha decay of Pa231  

Science Journals Connector (OSTI)

More detailed information is presented concerning the L and K x-ray spectra due to internal conversion of the electromagnetic transitions following the ? decay of Pa231. Some of the difficulties discussed in Ref. 1 are clarified by the new results.[RADIOACTIVITY Pa231; measured L and K Ac x-ray components, ?? and ?XL coin Ac227 deduced levels, ICC.

A. G. de Pinho; L. T. Auler; A. G. da Silva

1974-05-01T23:59:59.000Z

429

Surface Slope Metrology on Deformable Soft X-ray Mirrors  

SciTech Connect

We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situ visible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.

Yuan Sheng; Yashchuk, Valeriy V.; Celestre, Rich; Church, Matthew; McKinney, Wayne R.; Morrison, Greg; Warwick, Tony [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Goldberg, Kenneth A. [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2010-06-23T23:59:59.000Z

430

Transverse Coherence of the LCLS X-Ray Beam  

SciTech Connect

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

Not Available

2010-12-01T23:59:59.000Z

431

Single x-ray transmission system for bone mineral density determination  

SciTech Connect

Bones are the support of the body. They are composed of many inorganic compounds and other organic materials that all together can be used to determine the mineral density of the bones. The bone mineral density is a measure index that is widely used as an indicator of the health of the bone. A typical manner to evaluate the quality of the bone is a densitometry study; a dual x-ray absorptiometry system based study that has been widely used to assess the mineral density of some animals' bones. However, despite the success stories of utilizing these systems in many different applications, it is a very expensive method that requires frequent calibration processes to work properly. Moreover, its usage in small species applications (e.g., rodents) has not been quite demonstrated yet. Following this argument, it is suggested that there is a need for an instrument that would perform such a task in a more reliable and economical manner. Therefore, in this paper we explore the possibility to develop a new, affordable, and reliable single x-ray absorptiometry system. The method consists of utilizing a single x-ray source, an x-ray image sensor, and a computer platform that all together, as a whole, will allow us to calculate the mineral density of the bone. Utilizing an x-ray transmission theory modified through a version of the Lambert-Beer law equation, a law that expresses the relationship among the energy absorbed, the thickness, and the absorption coefficient of the sample at the x-rays wavelength to calculate the mineral density of the bone can be advantageous. Having determined the parameter equation that defines the ratio of the pixels in radiographies and the bone mineral density [measured in mass per unit of area (g/cm{sup 2})], we demonstrated the utility of our novel methodology by calculating the mineral density of Wistar rats' femur bones.

Jimenez-Mendoza, Daniel; Vargas-Vazquez, Damian [Division de Investigacion y Posgrado, Facultad de Ingenieria, Universidad Autonoma de Queretaro, Cerro de las Campanas s/n., C.P. 76010, Queretaro, Qro. (Mexico); Espinosa-Arbelaez, Diego G. [Posgrado en Ciencia e Ingenieria en Materiales, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Av. Universidad 3000, C.P. 04510, Coyoacan, Mexico D.F. (Mexico); Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Boulevard Juriquilla 3001, C.P. 76230, A.P. 1-1010, Juriquilla, Qro. (Mexico); Giraldo-Betancur, Astrid L. [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, Libramiento Norponiente 2000, C.P. 76230, Fracc. Real de Juriquilla, Qro. (Mexico); Hernandez-Urbiola, Margarita I. [Posgrado en Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Boulevard Juriquilla 3001, C.P. 76230, A.P. 1-1010, Juriquilla, Qro. (Mexico); Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Boulevard Juriquilla 3001, C.P. 76230, A.P. 1-1010, Juriquilla, Qro. (Mexico); Rodriguez-Garcia, Mario E. [Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Boulevard Juriquilla 3001, C.P. 76230, A.P. 1-1010, Juriquilla, Qro. (Mexico)

2011-12-15T23:59:59.000Z

432

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

433

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

434

Incoherent x-ray scattering in single molecule imaging  

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

435

The Sun as an X-Ray Star. II. Using the Yohkoh/Soft X-Ray Telescope-derived Solar Emission Measure versus Temperature to Interpret Stellar X-Ray Observations  

Science Journals Connector (OSTI)

This paper is the second of a project dedicated to using solar Yohkoh/SXT data as a guide and a template to interpret data on stellar coronae. In the light of the large differences in scope and approach between solar and stellar studies, we have developed a method to translate Yohkoh/SXT data of the whole solar corona into stellar-like data, i.e., to put them in the same format and context as the stellar ones. First from the Yohkoh/SXT images we derive the whole-Sun X-ray emission measure versus temperature [EM(T)], in the range 105.5-108 K, during the specific observation. Then, we synthesize the solar X-ray spectrum; finally, we fold the spectrum through the instrumental response of nonsolar X-ray observatories, for instance, ROSAT/PSPC and ASCA/SIS. Finally, we analyze such solar coronal data in the same band and with the same methods used for stellar observations, allowing a direct and homogeneous comparison with them. In this paper we present in detail our method and, as an example of results, we show and discuss EM(T) and stellar-like spectra for three phases of the solar cycle: maximum, intermediate phase, and minimum. The total amount and the distribution of the emission measure change dramatically during the cycle, in particular at temperatures above 106 K. We also show the EM(T) of the whole solar corona during a large flare. The ROSAT/PSPC- and ASCA/SIS-like X-ray spectra of the Sun as a star that we obtain are discussed in the context of stellar coronal physics. The Sun's coronal total luminosity in the ROSAT/PSPC band ranges from ?2.7 ? 1026 ergs s-1 (at minimum) to ?4.7 ? 1027 ergs s-1 (at maximum). We discuss future developments and possible applications of our method.

G. Peres; S. Orlando; F. Reale; R. Rosner; H. Hudson

2000-01-01T23:59:59.000Z

436

X-ray Emission from Massive StarsX-ray Emission from Massive Stars David CohenDavid Cohen  

E-Print Network (OSTI)

X-ray Emission from Massive StarsX-ray Emission from Massive Stars David CohenDavid Cohen/s)Velocity (km/s) #12;absorption emission emission occulted emission emission UV telescope side side front back #12;absorption emission emission occulted emission emission UV telescope side side front back #12;The

Cohen, David

437

High spatial resolution X-ray and gamma ray imaging system using diffraction crystals  

DOE Patents (OSTI)

A method and a device for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation are provided. The device comprises a plurality of arrays, with each array comprising a plurality of elements comprising a first collimator, a diffracting crystal, a second collimator, and a detector.

Smither, Robert K. (Hinsdale, IL)

2011-05-17T23:59:59.000Z

438

Beam characterization of a lab bench cold cathode ultra-soft x-ray generator  

E-Print Network (OSTI)

-source. Keywords: Ultra-soft X-rays (USX), USX Cold cathode generator, Gafchromic dosimetry, Aluminium K line. 1 and cell transformation) [1]. USX, however,5 pose significant problems in dosimetry and experimental design References hal-00858423,version1-5Sep2013 Author manuscript, published in "Nuclear Instruments and Methods

Paris-Sud XI, Université de

439

A new procedure for static RAM evaluation under x-ray pulses  

SciTech Connect

An original method, to identify the initial patterns that are the most favorable to obtain upsets under X-ray pulses, has been developed on Static RAMs in the standby mode. The results obtained with these initial patterns are interesting in order to analyze the radiation induced failures.

Marec, R.; Gaillard, R. (Nucletudes S.A., Les Ulis (France)); Mary, P.; Fairbank, X. (LRBA, Vernon (France)); Ferrant, R. (Thomson-CSF Semiconducteurs Specifiques, Saint Egreve (France)); Palau, J.M.; Gasiot, J. (Univ. Montpellier (France). Centre Electronique de Montpellier)

1994-12-01T23:59:59.000Z

440

The Analysis and Interpretation of Neutron and X-ray Specular Reflection  

Science Journals Connector (OSTI)

The analysis of neutron and X-ray reflectivity in terms of partial structure factors is described in detail. The method is shown to be an effective means of overcoming problems associated with phase and composition ambiguity. It also offers a means of enhancing the resolution of the experiment.

Lu, J.R.

1996-01-01T23:59:59.000Z

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


441

X-ray Computed Tomography of coal: Final report  

SciTech Connect

X-ray Computed Tomography (CT) is a method of mapping with x-rays the internal structures of coal. The technique normally produces 2-D images of the internal structures of an object. These images can be recast to create pseudo 3-D representations. CT of coal has been explored for a variety of different applications to coal and coal processing technology. In a comparison of CT data with conventional coal analyses and petrography, CT was found to offer a good indication of the total ash content of the coal. The spatial distribution of the coal mineral matter as seen with CT has been suggested as an indicator of coal washability. Studies of gas flow through coal using xenon gas as a tracer have shown the extremely complicated nature of the modes of penetration of gas through coal, with significant differences in the rates at which the gas can pass along and across the bedding planes of coal. In a special furnace designed to allow CT images to be taken while the coal was being heated, the pyrolysis and gasification of coal have been studied. Gasification rates with steam and CO/sub 2/ for a range of coal ranks have been obtained, and the location of the gasification reactions within the piece of coal can be seen. Coal drying and the progress of the pyrolysis wave into coal have been examined when the coal was subjected to the kind of sudden temperature jump that it might experience in fixed bed gasifier applications. CT has also been used to examine stable flow structures within model fluidized beds and the accessibility of lump coal to microbial desulfurization. 53 refs., 242 figs., 26 tabs.

Maylotte, D.H.; Spiro, C.L.; Kosky, P.G.; Lamby, E.J.

1986-12-01T23:59:59.000Z

442

The X-Ray Microcalorimeter Spectrometer for the International X-Ray Observatory  

SciTech Connect

The International X-Ray Observatory (IXO) is under formulation by NASA, ESA and JAXA for deployment in 2022. IXO emerged over the last 18 months as the NASA Constellation-X and ESA/JAXA X-Ray Evolving Universe Spectrometer (XEUS) missions were combined. The driving performance requirements for the X-Ray Microcalorimeter Spectrometer (XMS) are a spectral resolution of 2.5 eV over the central 2'x2' in the 0.3-7.0 keV band, and 10 eV to the edge of the 5'x5' field of view (FOV). The XMS is now based on a microcalorimeter array of Transition-Edge Sensor (TES) thermometers with Au/Bi absorbers and a SQUID MUX readout. One of the concepts studied as part of the mission formulation has a core 40x40 array corresponding to a 2'x2' FOV with 3'' pixels surrounded by an outer, annular 52x52 array of 6'' pixels that extends the field of view to 5.4'x5.4' with better than 10 eV resolution. There are several options for implementing the readout and cooling system of the XMS under study in the US, Europe and Japan. The ADR system will have from two to five stages depending on the performance of the cryocooler. Mechanical coolers with sufficient cooling power at 4K are available now, and {approx}2K coolers are under development. In this paper we give an overview of the XMS instrument, and some of the tradeoffs to be addressed for this observatory instrument.

Kelley, R. L.; Bandler, S. R.; Kilbourne, C. A.; Porter, F. S.; Shirron, P.; Smith, S. J.; Whitehouse, P. [NASA/Goddard Space Flight Center, Greenbelt, MD (United States); Doriese, W. B.; Irwin, K. [National Institute of Standards and Technology, Boulder, CO (United States); Ezoe, Y.; Ishisaki, Y.; Ohashi, T. [Tokyo Metropolitan University, Hachioji, Tokyo (Japan); Fujimoto, R.; Sato, K. [Faculty of Mathematics and Physics, Kanazawa University, Kanazawa (Japan); Gottardi, L.; Hartog, R. den; Herder, J.-W. den; Hoevers, H.; Korte, P. de; Kuur, J. van der [SRON Netherlands Institute for Space Research, Utrecht (Netherlands)] (and others)

2009-12-16T23:59:59.000Z

443

Polarized x-ray-absorption spectroscopy of the uranyl ion: Comparison of experiment and theory  

SciTech Connect

The x-ray linear dichroism of the uranyl ion (UO{sub 2}{sup 2+}) in uranium {ital L}{sub 3}-edge extended x-ray-absorption fine structure (EXAFS), and {ital L}{sub 1}- and {ital L}{sub 3}-edge x-ray-absorption near-edge structure (XANES), has been investigated both by experiment and theory. A striking polarization dependence is observed in the experimental XANES and EXAFS for an oriented single crystal of uranyl acetate dihydrate [UO{sub 2}(CH{sub 3}CO{sub 2}){sub 2}{center_dot}2H{sub 2}O], with the x-ray polarization vector aligned either parallel or perpendicular to the bond axis of the linear uranyl cation (O-U-O). Single-crystal results are compared to experimental spectra for a polycrystalline uranyl acetate sample and to calculations using the {ital ab} {ital initio} multiple-scattering (MS) code FEFF 6. Theoretical XANES spectra for uranyl fluoride (UO{sub 2}F{sub 2}) reproduce all the features of the measured uranyl acetate spectra. By identifying scattering paths which contribute to individual features in the calculated spectrum, a detailed understanding of the {ital L}{sub 1}-edge XANES is obtained. MS paths within the uranyl cation have a notable influence upon the XANES. The measured {ital L}{sub 3}-edge EXAFS is also influenced by MS, especially when the x-ray polarization is parallel to the uranyl species. These MS contributions are extracted from the total EXAFS and compared to calculations. The best agreement with the isolated MS signal is obtained by using nonoverlapped muffin-tin spheres in the FEFF 6 calculation. This contrasts the {ital L}{sub 1}-edge XANES calculations, in which overlapping was required for the best agreement with experiment. {copyright} {ital 1996 The American Physical Society.}

Hudson, E.A.; Allen, P.G.; Terminello, L.J. [Glenn T. Seaborg Institute for Transactinium Science, Lawrence Livermore National Laboratory, University of California, Livermore, California 94551 (United States)] [Glenn T. Seaborg Institute for Transactinium Science, Lawrence Livermore National Laboratory, University of California, Livermore, California 94551 (United States); Denecke, M.A.; Reich, T. [Institut fuer Radiochemie, Forschungszentrum Rossendorf, Postfach 510119, D-01314 Dresden (Germany)] [Institut fuer Radiochemie, Forschungszentrum Rossendorf, Postfach 510119, D-01314 Dresden (Germany)

1996-07-01T23:59:59.000Z

444

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

E-Print Network (OSTI)

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

Johnson, Robert E.

445

X-ray-induced phase transformation in congruent and vapor-transport-equilibrated lithium tantalate  

E-Print Network (OSTI)

X-ray-induced phase transformation in congruent and vapor-transport-equilibrated lithium tantalate an effect of a partially reversible x-ray-induced increase of diffuse x-ray scattering in both congruent been attributed to x-ray-induced decay of the ferroelectric phase at room temperature. The x-ray

Byer, Robert L.

446

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

E-Print Network (OSTI)

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

Mauro Orlandini

2004-02-26T23:59:59.000Z

447

Apparatus for generating x-ray holograms  

DOE Patents (OSTI)

Apparatus for x-ray microholography of living biological materials. A Fourier transform holographic configuration is described as being most suitable for the 3-dimensional recording of the physical characteristics of biological specimens. The use of a spherical scatterer as a reference and a charge-coupled device two-dimensional detector array placed in the forward direction relative to the incident x-radiation for viewing electromagnetic radiation simultaneously scattered from both the specimen and the reference scatterer permits the ready reconstruction of the details of the specimen from the fringe pattern detected by the charge-coupled device. For example, by using a nickel reference scatter at 4.5 nm, sufficient reference illumination is provided over a wide enough angle to allow similar resolution in both transverse and longitudinal directions. Both laser and synchrotron radiation sources are feasible for generating microholographs. Operation in the water window (2.4 to 4.5 nm) should provide maximum contrast for features of the specimen and spatial resolution on the order of the wavelength of x-radiation should be possible in all three dimensions, which is sufficient for the visualization of many biological features. It is anticipated that the present apparatus will find utility in other areas as well where microscopic physical details of a specimen are important. A computational procedure which enables the holographic data collected by the detector to be used to correct for misalignments introduced by inexact knowledge of the relative positions of the spherical reference scatterer and the sample under investigation has been developed. If the correction is performed prior to reconstruction, full compensation can be achieved and a faithfully reconstructed image produced.

Rhodes, Charles K. (Chicago, IL); Boyer, Keith (Los Alamos, NM); Solem, Johndale C. (Los Alamos, NM); Haddad, Waleed S. (Chicago, IL)

1990-01-01T23:59:59.000Z

448

Apparatus for generating x-ray holograms  

DOE Patents (OSTI)

Apparatus for x-ray microholography of living biological materials. A Fourier transform holographic configuration is described as being most suitable for the 3-dimensional recording of the physical characteristics of biological specimens. The use of a spherical scatterer as a reference and a charge-coupled device two-dimensional detector array placed in the forward direction relative to the incident x-radiation for viewing electromagnetic radiation simultaneously scattered from both the specimen and the reference scatterer permits the ready reconstruction of the details of the specimen from the fringe pattern detected by the charge-coupled device. For example, by using a nickel reference scatter at 4.5 nm, sufficient reference illumination is provided over a wide enough angle to allow similar resolution in both transverse and longitudinal directions. Both laser and synchrotron radiation sources are feasible for generating microholographs. Operation in the water window (2.4 to 4.5 nm) should provide maximum contrast for features of the specimen and spatial resolution on the order of the wavelength of x-radiation should be possible in all three dimensions, which is sufficient for the visualization of many biological features. It is anticipated that the present apparatus will find utility in other areas as well where microscopic physical details of a specimen are important. A computational procedure which enables the holographic data collected by the detector to be used to correct for misalignments introduced by inexact knowledge of the relative positions of the spherical reference scatterer and the sample under investigation has been developed. If the correction is performed prior to reconstruction, full compensation can be achieved and a faithfully reconstructed image produced. 7 figs.

Rhodes, C.K.; Boyer, K.; Solem, J.C.; Haddad, W.S.

1990-09-11T23:59:59.000Z

449

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.

450

X-ray Crystallographic Center (XCC) User Registration Form Peter Y. Zavalij X-ray Crystallographi Center 091 Chemistry Bldg. / College Park, MD 20742  

E-Print Network (OSTI)

X-ray Crystallographic Center (XCC) User Registration Form Peter Y. Zavalij X-ray Crystallographi. or advisor confirmation e-mail X-ray Diffractometer that will be used: User Level and Status Smart Apex2X'Pert Pro MRD (Reflectivity & low angles) Xeuss (Small/Wide Angle X-ray Scattering) Submitting user ­ only

Thirumalai, Devarajan

451

Lunar X-ray fluorescence observations by the Chandrayaan-1 X-ray Spectrometer (C1XS): Results from the nearside southern highlands  

E-Print Network (OSTI)

Lunar X-ray fluorescence observations by the Chandrayaan-1 X-ray Spectrometer (C1XS): Results from Spectroscopy a b s t r a c t The Chandrayaan-1 X-ray Spectrometer (C1XS) flown on-board the first Indian lunar mission Chan- drayaan-1, measured X-ray fluorescence spectra during several episodes of solar flares

Wieczorek, Mark

452

Thermonuclear X-ray Bursts: Theory vs. Observations  

E-Print Network (OSTI)

I review our theoretical understanding of thermonuclear flashes on accreting neutron stars, concentrating on comparisons to observations. Sequences of regular Type I X-ray bursts from GS 1826-24 and 4U 1820-30 are very well described by the theory. I discuss recent work which attempts to use the observed burst properties in these sources to constrain the composition of the accreted material. For GS 1826-24, variations in the burst energetics with accretion rate indicate that the accreted material has solar metallicity; for 4U 1820-30, future observations should constrain the hydrogen fraction, testing evolutionary models. I briefly discuss the global bursting behavior of burst sources, which continues to be a major puzzle. Finally, I turn to superbursts, which naturally fit into the picture as unstable carbon ignition in a thick layer of heavy elements. I present new time-dependent models of the cooling tails of superbursts, and discuss the various interactions between superbursts and normal Type I bursts, and what can be learned from them.

Andrew Cumming

2003-11-18T23:59:59.000Z

453

Comparison of SOFC Cathode Microstructure Quantified using X-ray Nanotomography and Focused Ion Beam - Scanning Electron Microscopy  

SciTech Connect

X-ray nanotomography and focused ion beam scanning electron microscopy (FIB?SEM) have been applied to investigate the complex 3D microstructure of solid oxide fuel cell (SOFC) electrodes at spatial resolutions of 45 nm and below. The application of near edge differential absorption for x-ray nanotomography and energy selected backscatter detection for FIB–SEM enable elemental mapping within the microstructure. Using these methods, non?destructive 3D x-ray imaging and FIB–SEM serial sectioning have been applied to compare three?dimensional elemental mapping of the LSM, YSZ, and pore phases in the SOFC cathode microstructure. The microstructural characterization of an SOFC cathode is reported based on these measurements. The results presented demonstrate the viability of x-ray nanotomography as a quantitative characterization technique and provide key insights into the SOFC cathode microstructure.

Nelson, George J.; Harris, William H.; Lombardo, Jeffrey J.; Izzo, Jr., John R.; Chiu, W. K. S.; Tanasini, Pietro; cantoni, Marco; Van herle, Jan; Comninellis, Christos; Andrews, Joy C.; Liu, Yijin; Pianetta, Piero; Chu, Yong

2011-01-01T23:59:59.000Z

454

National Ignition Facility core x-ray streak camera  

SciTech Connect

The National Ignition Facility (NIF) core x-ray streak camera will be used for laser performance verification experiments as well as a wide range of physics experiments in the areas of high-energy-density science, inertial confinement fusion, and basic science. The x-ray streak camera system is being designed to record time-dependent x-ray emission from NIF targets using an interchangeable family of snouts for measurements such as one-dimensional (1D) spatial imaging or spectroscopy. the NIF core x-ray streak camera will consist of an x-ray-sensitive photocathode that detects x rays with 1D spatial resolution coupled to an electron streak tube to detect a continuous time history of the x rays incident on the photocathode over selected time periods. A charge-coupled-device (CCD) readout will record the signal from the streak tube. The streak tube, CCD, and associated electronics will reside in an electromagnetic interference, and electromagnetic pulse protected, hermetically sealed, temperature-controlled box whose internal pressure is approximately 1 atm. The streak tube itself will penetrate through the wall of the box into the target chamber vacuum. We are working with a goal of a spatial resolution of 15 lp/mm with 50% contrast transfer function at the photocathode and adjustment sweep intervals of 1--50 ns. The camera spectral sensitivity extends from soft x rays to 20 keV x rays, with varying quantum efficiency based on photocathode selection. The system will have remote control, monitoring, and Ethernet communications through an embedded controller. The core streak camera will be compatible with the instrument manipulators at the OMEGA (University of Rochester) and NIF facilities.

Kimbrough, J. R.; Bell, P. M.; Christianson, G. B.; Lee, F. D.; Kalantar, D. H.; Perry, T. S.; Sewall, N. R.; Wootton, A. J.

2001-01-01T23:59:59.000Z

455

The radiation-tolerant x-ray monitor  

SciTech Connect

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

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

2008-10-15T23:59:59.000Z

456

X-ray backscatter imaging of nuclear materials  

DOE Patents (OSTI)

The energy of an X-ray beam and critical depth are selected to detect structural discontinuities in a material having an atomic number Z of 57 or greater. The critical depth is selected by adjusting the geometry of a collimator that blocks backscattered radiation so that backscattered X-ray originating from a depth less than the critical depth is not detected. Structures of Lanthanides and Actinides, including nuclear fuel rod materials, can be inspected for structural discontinuities such as gaps, cracks, and chipping employing the backscattered X-ray.

Chapman, Jeffrey Allen; Gunning, John E; Hollenbach, Daniel F; Ott, Larry J; Shedlock, Daniel

2014-09-30T23:59:59.000Z

457

Cryogenic X-Ray Diffraction Microscopy for Biological Samples  

Science Journals Connector (OSTI)

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

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

2009-11-05T23:59:59.000Z

458

Cryogenic X-ray Diffraction Microscopy for Biological Samples  

SciTech Connect

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

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

2011-12-31T23:59:59.000Z

459

X-Ray Afterglows from Gamma-Ray Bursts  

Science Journals Connector (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 postburst reacceleration 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

1997-01-01T23:59:59.000Z

460

Current Problems for X-ray Emission from Radio Jets  

E-Print Network (OSTI)

A list is presented of known extragalactic radio jets which also have associated X-ray emission. The canonical emission processes for the production of X-rays are reviewed and the sources are categorized on the basis of our current understanding. Although it seems clear that the X-ray emission is non-thermal, the two competing processes, synchrotron and inverse Compton emissions, arise from extremely high energy (synchrotron) or extremely low energy (beaming models with IC emission), relativistic electrons. Only synchrotron self-Compton emission from a few hotspots provides information on the `normal' energy range of the electrons responsible for the observed radio emission.

D. E. Harris

2000-12-17T23:59:59.000Z

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461

X-Ray Directional Dichroism of a Polar Ferrimagnet  

Science Journals Connector (OSTI)

In a polar ferrimagnet GaFeO3, we have found a novel magneto-optical effect, termed x-ray nonreciprocal directional dichroism (XNDD), that the x-ray absorption at around the K edge of an Fe ion depends on whether the x-ray propagation vector is parallel or antiparallel to the outer product of the magnetization and electric-polarization vectors. The XNDD spectroscopy as demonstrated here can be a useful tool to probe the local magnetism in noncentrosymmetric systems such as magnetic interfaces and nanostructures.

M. Kubota, T. Arima, Y. Kaneko, J. P. He, X. Z. Yu, and Y. Tokura

2004-03-29T23:59:59.000Z

462

Spatiotemporal focusing dynamics in plasmas at X-ray wavelength  

SciTech Connect

Using a finite curvature beam, we investigate here the spatiotemporal focusing dynamics of a laser pulse in plasmas at X-ray wavelength. We trace the dependence of curvature parameter on the focusing of laser pulse and recognize that the self-focusing in plasma is more intense for the X-ray laser pulse with curved wavefront than with flat wavefront. The simulation results demonstrate that spatiotemporal focusing dynamics in plasmas can be controlled with the appropriate choice of beam-plasma parameters to explore the high intensity effects in X-ray regime.

Sharma, A., E-mail: a-physics2001@yahoo.com; Tibai, Z. [Institute of Physics, University of Pecs, Pecs–7624 (Hungary)] [Institute of Physics, University of Pecs, Pecs–7624 (Hungary); Hebling, J. [Institute of Physics, University of Pecs, Pecs–7624 (Hungary) [Institute of Physics, University of Pecs, Pecs–7624 (Hungary); Szentagothai Research Centre, University of Pecs, Pecs-7624 (Hungary); Mishra, S. K. [Institute for Plasma Research, Gandhinagar (India)] [Institute for Plasma Research, Gandhinagar (India)

2014-03-15T23:59:59.000Z

463

Soft x-ray resist characterization: Studies with a laser plasma x-ray source  

SciTech Connect

Little work has been performed to characterize the exposure sensitivity, contrast, and tone of candidate resists for photon energies between 100--300 eV, the range in which projection soft x-ray lithography will be developed. We report here the characterization of near-edge x-ray absorption fine structure (NEXAFS) spectra, exposure sensitivity, contrast, and post-exposure processing of selected polysilane resists at photon energies close to the Si L{sub 2,3} absorption edge (100 eV). We find absorption resonance features in the NEXAFS spectra which we assign to excitation into Si--Si and Si--C {sigma}* orbitals. Using monochromatized XUV exposures on the Si--Si {sigma}* resonance at 105 eV, followed by solvent dissolution development, we have measured the exposure sensitivity curves of these resists. We find sensitivities in the range of 600--3000 mJ/cm{sup 2} and contrasts in the range from 0.5--1.4, depending on the polysilane side chain. We have also performed exposure sensitivity measurements at 92 eV, below the edge. Sensitivity decreases slightly compared to 105 eV exposures and the saturation depth and contrast both increase, as expected. We find also that exposing resist films to oxygen after XUV exposure, but before development increases the sensitivity markedly. 7 figs.

Kubiak, G.D.; Outka, D.A. (Sandia National Labs., Livermore, CA (USA)); Zeigler, J.M. (Sandia National Labs., Albuquerque, NM (USA))

1990-01-01T23:59:59.000Z

464

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

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

465

Information-Theoretic Methods for Identifying Relationships among Climate Variables  

E-Print Network (OSTI)

Information-theoretic quantities, such as entropy, are used to quantify the amount of information a given variable provides. Entropies can be used together to compute the mutual information, which quantifies the amount of information two variables share. However, accurately estimating these quantities from data is extremely challenging. We have developed a set of computational techniques that allow one to accurately compute marginal and joint entropies. These algorithms are probabilistic in nature and thus provide information on the uncertainty in our estimates, which enable us to establish statistical significance of our findings. We demonstrate these methods by identifying relations between cloud data from the International Satellite Cloud Climatology Project (ISCCP) and data from other sources, such as equatorial pacific sea surface temperatures (SST).

Knuth, Kevin H; Rossow, William B

2014-01-01T23:59:59.000Z

466

X-ray absorption spectroscopic studies of mononuclear non-heme iron enzymes  

SciTech Connect

Fe-K-edge X-ray absorption spectroscopy (XAS) has been used to investigate the electronic and geometric structure of the iron active site in non-heme iron enzymes. A new theoretical extended X-ray absorption fine structure (EXAFS) analysis approach, called GNXAS, has been tested on data for iron model complexes to evaluate the utility and reliability of this new technique, especially with respect to the effects of multiple-scattering. In addition, a detailed analysis of the 1s{yields}3d pre-edge feature has been developed as a tool for investigating the oxidation state, spin state, and geometry of iron sites. Edge and EXAFS analyses have then been applied to the study of non-heme iron enzyme active sites.

Westre, T.E.

1996-01-01T23:59:59.000Z

467

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

E-Print Network (OSTI)

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

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

2014-02-27T23:59:59.000Z

468

Broad-band Spectral Properties of Accreting X-ray Binary Pulsars  

E-Print Network (OSTI)

Broad-band spectra of accreting X-ray binary pulsars can be fit by a phenomenological model composed by a power law with a high energy rollover above 10 keV, plus a blackbody component with a temperature of few hundred eV. While, at least qualitatively, the hard tail can be explained in terms of (inverse) Compton scattering, the origin of the soft component cannot find a unique explanation. Recently a qualitative picture able to explain the overall broad band-spectrum of luminous X-ray pulsars was carried out by taking into account the effect of bulk Comptonization in the accretion column. After a review on these recent theoretical developments, I will present a case study of how different modelization of the continuum affect broad features, in particular the cyclotron resonance features in Vela X-1.

Mauro Orlandini

2005-10-10T23:59:59.000Z

469

E-Print Network 3.0 - airborne lead x-ray Sample Search Results  

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

Pulsars... you'd . . . Active Galactic . . . X-ray binaries Pulsars and relatives Gamma-ray bursts Gravitational... 1 - Type 2 X-ray binaries - Low mass X-ray binaries (LMXBs)...

470

E-Print Network 3.0 - advanced x-ray timing Sample Search Results  

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

AND COMETS: RELATIONSHIP WITH SOLAR X-RAYS AND SOLAR WIND Summary: with the occurrence of solar X-ray flare, when light travel time delay is accounted, suggesting that X-rays...

471

X-RAY ABSORPTION STUDIES OF GRAPHITE INTERCALATES AND METAL-AMMONIA SOLUTION  

E-Print Network (OSTI)

I. INTRODUCTION A. X-Ray Absorption Spectroscopy B. Graphiteacknowledged. The X-Ray absorption data could not have beenI INTRODUCTION X-ray absorption, spectroscopy (XAS) has been

Robertson, A.S.

2010-01-01T23:59:59.000Z

472

AN X-RAY ABSORPTION SPECTROSCOPY STUDY OF MANGANESE CONTAINING COMPOUNDS AND PHOTOSYNTHETIC SPINACH CHLOROPLASTS  

E-Print Network (OSTI)

II. Extended X-ray Absorption Fine Structure (EXAFS) TheoryIII. X-ray Absorption Spectroscopy (XAS) ExperimentIII. EXTENDED X-RAY ABSORPTION FINE STRUCTURE (EXAFS) DATA

Kirby, Jon Allan

2012-01-01T23:59:59.000Z

473

X-ray Absorption Spectroscopy Study of Prototype Chemical Systems: Theory vs. Experiment  

E-Print Network (OSTI)

acids by Near Edge X-ray Absorption Fine Structure (NEXAFS)X-ray Absorption Spectroscopy Study of Prototype ChemicalGlaeser Spring 2010 X-ray Absorption Spectroscopy Study of

Schwartz, Craig Philip

2010-01-01T23:59:59.000Z

474

X-ray absorption spectroscopy at the Ni-K edge in Stackhousia tryonii Bailey hyperaccumulator  

E-Print Network (OSTI)

X-ray absorption spectroscopy at the Ni–K edge inin vivo by micro x-ray absorption spectroscopy (XAS) at theNi–K edge. Both x-ray absorption near edge structure and

Kachenko, A.

2009-01-01T23:59:59.000Z

475

Theoretical studies of potential energy surfaces and computational methods  

SciTech Connect

This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

Shepard, R. [Argonne National Laboratory, IL (United States)

1993-12-01T23:59:59.000Z

476

Plasma debris sputter resistant x-ray mirror  

Science Journals Connector (OSTI)

A diamond-like carbon (DLC) mirror, used as a grazing incident mirror in a plasma x-ray source, exhibits a high resistance to plasma debris sputtering. Good mirror reflectivity at a...

Amano, Sho; Inoue, Tomoaki; Harada, Tetsuo

2013-01-01T23:59:59.000Z

477

New Directions in X-ray Scattering - SSRL  

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

6, 2006 A summary of the workshop on New Directions in X-ray Scattering On Dec 6th, we held a day long workshop to solicit user input on the new directions that the SSRL...

478

Synchroton X-Ray Studies of Liquid-Vapor Interfaces  

Science Journals Connector (OSTI)

The variation of density across the liquid-vapor interface from essentially zero density far out in the vapor phase to a homogeneous density deep in the liquid phase can be determined by X-ray reflectivity mea...

J. Als-Nielsen

1988-01-01T23:59:59.000Z

479